WO2018159777A1 - Assembled battery - Google Patents

Abstract

An assembled battery (16) has a plurality of lithium ion cells (161) that are electrically connected to each other. Each of the lithium ion cells (161) is a metal case-type cell that has a metal case for housing a positive electrode, a negative electrode, and an electrolyte. Each of the respective metal case-type cells (161) is connected in series to one of the metal case-type cells (161). The positive electrode has a positive electrode active material of an olivine structure. The negative electrode has a negative electrode active material which includes a plurality of carbon layers stacked on top of each other and in which the average interlayer distance among the carbon layers is equal to or more than the diameter of a lithium atom. The assembled battery (16) has a metal case-type cell fixing part (163) that fixes the metal case-type cells (161) to each other.

Description

Assembled battery

The present invention relates to an assembled battery having a plurality of lithium ion cells.

Vehicles and electronic devices are equipped with secondary batteries. Conventionally, lead-acid batteries have been used as secondary batteries. In recent years, lithium ion cell batteries have been used as secondary batteries instead of lead-acid batteries.

For example, Patent Document 1 proposes a lithium ion assembled battery having a plurality of lithium ion cells connected in series. The lithium ion cell described in Patent Document 1 includes a positive electrode having a positive electrode active material containing lithium iron phosphate and a negative electrode having a graphite-based negative electrode active material.

Japanese Patent No. 5549684

The inventor of the present application examined mounting a lithium ion assembled battery as described in Patent Document 1 on a straddle-type vehicle such as a motorcycle instead of a lead storage battery. As a result, it was found that the lithium ion cell deteriorates depending on the usage environment of the saddle riding type vehicle.

The present invention is to provide an assembled battery that can suppress deterioration of a lithium ion cell even in an environment where the assembled battery mounted in a saddle-ride type vehicle is used.

The inventor of the present application has compared the use environment of the lead storage battery mounted on the saddle riding type vehicle and the use environment of the lead storage battery mounted on the automobile (four-wheeled vehicle).

In a straddle-type vehicle using an engine as a drive source and an automobile using an engine as a drive source, the lead storage battery is discharged with a large current to drive the starter motor when the engine is started. In straddle-type vehicles that use a motor as a drive source and automobiles that use a motor as a drive source, the lead-acid battery discharges with a large current to drive the motor during driving. An automobile using an engine as a drive source includes an engine room for accommodating the engine. Moreover, the motor vehicle which uses a motor as a drive source is provided with the motor room for accommodating a motor. A lead storage battery mounted on an automobile is accommodated in an engine room or a motor room. For this reason, even in a low-temperature environment such as nighttime in winter, the temperature of the lead storage battery mounted on the automobile is unlikely to be extremely low. On the other hand, the saddle riding type vehicle does not include an engine room or a motor room. The lead storage battery mounted on the saddle-ride type vehicle is arranged in a state exposed to the outside or only covered with a vehicle body cover. Therefore, the temperature of the lead storage battery mounted on the saddle riding type vehicle is greatly lowered under a low temperature environment such as nighttime in winter. Therefore, a lead storage battery mounted on a saddle-ride type vehicle tends to discharge a large current at a lower temperature than a lead storage battery mounted on an automobile.

Further, straddle-type vehicles are required to be lighter and smaller than automobiles. A lead-acid battery of a saddle-ride type vehicle using an engine as a drive source has a smaller weight and volume than a lead-acid battery mounted on an automobile using the engine as a drive source. That is, a lead storage battery mounted on a saddle-ride type vehicle using an engine as a drive source has a smaller capacity than a lead storage battery mounted on an automobile using the engine as a drive source. Moreover, the lead acid battery mounted in the saddle-ride type vehicle using the motor as the drive source has a smaller weight and volume than the lead acid battery mounted in the automobile using the motor as the drive source. That is, a lead storage battery mounted on a saddle-ride type vehicle using a motor as a drive source has a smaller capacity than a lead storage battery mounted on an automobile using a motor as a drive source. Thus, since the lead storage battery mounted on the saddle-ride type vehicle has a smaller capacity than the lead storage battery mounted on the automobile, the lead storage battery mounted on the saddle riding type vehicle is charged more than the lead storage battery mounted on the automobile. Tend to be more frequent.
Therefore, the lead storage battery mounted on the saddle riding type vehicle tends to be charged more frequently than the lead storage battery mounted on the automobile at a lower temperature than the lead storage battery mounted on the automobile.

The inventor of the present application, as described above, has a tendency that a lead storage battery mounted on a saddle-ride type vehicle discharges a large current at a lower temperature than a lead storage battery mounted on an automobile, and It has been found that there is a tendency to be charged more frequently than a lead storage battery mounted in an automobile at a lower temperature than the lead storage battery mounted. The inventor of the present application studied to mount a lithium ion assembled battery as described in Patent Document 1 on a saddle riding type vehicle instead of a lead storage battery. However, since the usage environment of the lead storage battery mounted on the saddle-ride type vehicle is the above-described environment, when the lithium ion assembled battery as described in Patent Document 1 is mounted on the saddle-ride type vehicle, lithium I noticed that the ion cell tends to deteriorate.

The inventor of the present application studied charging and discharging a lithium ion cell having a positive electrode active material containing lithium iron phosphate and a graphite-based negative electrode active material described in Patent Document 1 in a low temperature state. As a result, the following was found.
It was found that the lithium ion cell can discharge a large current required for the saddle riding type vehicle even in a low temperature environment. Further, it was found that when the lithium ion cell is slowly charged over time, the lithium ion cell hardly deteriorates even if the discharge is repeated in a low temperature environment.
However, it was found that when the lithium ion cell is repeatedly charged in a low temperature environment, the lithium ion cell is likely to deteriorate.

A negative electrode having a graphite-based negative electrode active material has a crystal structure in which layers of carbon graphite (graphite) are stacked.
When the lithium ion cell is charged, the lithium ions move from the positive electrode to the negative electrode and enter between the layers of graphite laminated on the negative electrode. On the other hand, during discharge of the lithium ion cell, lithium ions exit from between the graphite layers in the negative electrode and move to the positive electrode.
In the negative electrode, the distance between the graphite layers is slightly smaller than the diameter of the lithium atoms. Therefore, when lithium ions enter between the graphite layers in the negative electrode during charging of the lithium ion cell, the space between the graphite layers is expanded. On the other hand, if lithium ions come out between the graphite layers during the discharge of the lithium ion cell, the space between the graphite layers is narrowed. When the charging and discharging of the lithium ion cell are repeated, the expansion and contraction of the gaps in the graphite layer are repeated as lithium ions repeatedly enter and exit between the graphite layers. As a result, the laminated state of the graphite layer changes. Thereby, it turned out that the crystal structure of a negative electrode changes a lot. This was found to be a factor in the deterioration of the negative electrode.

The inventor of the present application examined using a negative electrode active material having a plurality of laminated carbon layers instead of a negative electrode active material having a plurality of laminated graphite layers as a negative electrode of a lithium ion cell. The carbon here is non-graphite (non-graphite). More specifically, as the negative electrode active material, the use of a negative electrode active material having an average interlayer distance of a plurality of carbon layers equal to or greater than the diameter of lithium ions was examined. As a result, the following was found.
Since the average inter-layer distance of multiple carbon layers is equal to or greater than the diameter of lithium ions, even when lithium ions enter between adjacent carbon layers in the negative electrode when charging a lithium ion cell, Can hardly be spread. Further, even when lithium ions come out between adjacent carbon layers during discharge of the lithium ion cell, the distance between adjacent carbon layers does not change much. That is, even when lithium ions enter and exit between the carbon layers during charging and discharging of the lithium ion cell, the average interlayer distance between the plurality of carbon layers hardly changes. Therefore, the lamination state of the plurality of carbon layers hardly changes. Thereby, it turned out that the crystal structure of a negative electrode does not change so much. Therefore, it turned out that deterioration of a negative electrode can be suppressed. Therefore, it was found that deterioration of the lithium ion cell having this negative electrode can be suppressed. Further, it has been found that, when the negative electrode has the above configuration, deterioration of the lithium ion cell can be suppressed even when the frequency of charging and discharging of the lithium ion cell is increased. Furthermore, it has been found that when the negative electrode has the above-described configuration, the lithium ion cell having the negative electrode can suppress deterioration even when charged or discharged at a low temperature. Therefore, it was found that even when this lithium ion cell is mounted on a saddle-ride type vehicle and the frequency of charging and discharging of the lithium ion cell increases at a low temperature, deterioration of the lithium ion cell can be suppressed.

Based on the above findings, the inventors of the present application have completed the present invention. The present invention will be described below.

(1) The assembled battery of the present invention is an assembled battery having a plurality of lithium ion cells electrically connected to each other, and each of the plurality of lithium ion cells includes one positive electrode, one negative electrode, A metal case-type cell having an electrolyte solution or a solid electrolyte, the one positive electrode, the one negative electrode, and a metal case containing the electrolyte solution or the solid electrolyte, and the plurality of metal case-type cells. Each is connected in series to any of the plurality of metal case-type cells, the positive electrode has a positive electrode active material having an olivine structure, and the negative electrode includes a plurality of carbon layers stacked. And a negative electrode active material in which an average interlayer distance of the plurality of carbon layers is equal to or greater than a diameter of lithium atoms, and the assembled battery fixes the metal case type cells to each other. Having.

According to this configuration, each of the plurality of metal case type cells is connected in series to one of the plurality of metal case type cells. The larger the number of metal case cells connected in series with each other, the higher the output voltage of the assembled battery. By increasing the number of metal case type cells connected in series with each other, the assembled battery can be used in a usage environment that requires a high output voltage.

The metal case type cell is a lithium ion cell. Lithium ion cells have lower weight energy density and volumetric energy density than lead acid batteries. Therefore, when an assembled battery having a plurality of lithium ion cells is mounted on a saddle riding type vehicle instead of a lead storage battery, the saddle riding type vehicle can be reduced in weight and size while maintaining the capacity of the battery. Alternatively, the capacity of the battery can be increased without increasing the size and weight of the saddle riding type vehicle. By increasing the capacity of the assembled battery excessively, the burden on each of the plurality of metal case type cells included in the assembled battery is reduced, so that deterioration of the metal case type cell can be suppressed.

Each of the plurality of metal case-type cells (lithium ion cells) has one positive electrode, one negative electrode, and an electrolytic solution or a solid electrolyte. The negative electrode of the metal case type cell includes a negative electrode active material including a carbon layer instead of a graphite layer, and includes a negative electrode active material in which an average interlayer distance of a plurality of carbon layers is equal to or greater than a diameter of lithium atoms.
Since the average interlaminar distance of the plurality of carbon layers is equal to or greater than the diameter of lithium ions, even when lithium ions enter between adjacent carbon layers in the negative electrode, There is almost no gap between them. Further, even when lithium ions come out between adjacent carbon layers during discharge of the metal case type cell, the distance between adjacent carbon layers does not change much. That is, even when lithium ions enter and exit between the carbon layers during charging and discharging of the metal case type cell, the average interlayer distance between the plurality of carbon layers hardly changes. Therefore, the lamination state of the carbon layer hardly changes. Thereby, the crystal structure of a negative electrode does not change so much. Therefore, deterioration of the negative electrode can be suppressed. Therefore, deterioration of the metal case type cell having the negative electrode can be suppressed. Therefore, deterioration of the metal case type cell having the negative electrode can be suppressed. Moreover, even if the frequency of charge and discharge of a metal case type cell becomes high because a negative electrode has the said structure, deterioration of a metal case type cell can be suppressed. Furthermore, since the negative electrode has the above-described configuration, the metal case type cell having the negative electrode can suppress deterioration even at a low temperature. Therefore, even if this metal case type cell is mounted on a saddle riding type vehicle and the frequency of charging and charging of the metal case type cell is increased in a low temperature state, deterioration of the metal case type cell (lithium ion cell) can be suppressed.

In addition, since the positive electrode of the metal case type cell contains a positive electrode active material having an olivine structure, the metal case type cell (lithium ion cell) is unlikely to deteriorate even when charging and discharging are repeated. Therefore, even if charging and discharging of the metal case cell are repeated in a low temperature environment, the metal case cell (lithium ion cell) is not easily deteriorated. Therefore, even if an assembled battery having a plurality of metal case cells is mounted on a saddle-ride type vehicle and charging and discharging of the assembled battery are repeated relatively frequently, the metal case cell (lithium ion cell) is deteriorated. Can be suppressed. That is, it is possible to suppress the deterioration of the metal case type cell (lithium ion cell) even in the usage environment of the assembled battery mounted on the saddle riding type vehicle.
Furthermore, the olivine structure of the positive electrode active material is a hexagonal close-packed charge structure and a stable crystal structure. Therefore, the metal case type cell (lithium ion cell) having the above-described configuration can be used even in a high temperature environment.

In addition, the positive electrode active material has an olivine structure, and further includes a plurality of carbon layers in which the negative electrode active material is laminated, and the average interlayer distance of the plurality of carbon layers is equal to or greater than the diameter of the lithium atom. Therefore, deterioration can be suppressed even in a low temperature state. Therefore, even if this metal case type cell is mounted on a saddle riding type vehicle and the frequency of charging and discharging of the metal case type cell is increased at a low temperature, deterioration of the metal case type cell (lithium ion cell) can be suppressed. I understood.

Further, each of the plurality of metal case type cells is a metal case type cell having one positive electrode, one negative electrode, and a metal case containing an electrolytic solution or a solid electrolyte. The metal case has high heat dissipation. Therefore, when the plurality of metal case cells are charged and discharged, each of the plurality of metal case cells dissipates heat even if the plurality of metal case cells generate heat. Thereby, the temperature rise of the assembled battery which has a some metal case type | mold cell can be suppressed. Therefore, even if an assembled battery having a plurality of metal case type cells is mounted on a saddle riding type vehicle and the assembled battery is discharged with a large current, the temperature rise of the assembled battery can be suppressed. As a result, deterioration of the metal case type cell (lithium ion cell) can be suppressed. That is, even in an environment where a battery pack mounted on a saddle riding type vehicle is used, deterioration of the metal case type cell (lithium ion cell) due to heat generation during charging or discharging can be suppressed.

Furthermore, the plurality of metal case type cells are fixed to each other by the metal case type cell fixing portion. Therefore, the position of a plurality of metal case cells can be maintained with a layout that takes into consideration the heat dissipation of the metal case cells. For example, it can be maintained in a state where an appropriate gap is left between the metal case type cells. Thereby, even when a plurality of metal case type cells generate heat during charging and discharging of the plurality of metal case type cells, an increase in temperature of the assembled battery can be suppressed. Therefore, even when an assembled battery having a plurality of metal case-type cells is mounted on a saddle riding type vehicle and the assembled battery is discharged with a large current, the temperature rise of the assembled battery can be further suppressed. . As a result, the deterioration of the metal case type cell (lithium ion cell) can be further suppressed. That is, even in an environment where a battery pack mounted on a saddle riding type vehicle is used, deterioration of the metal case type cell (lithium ion cell) due to heat generation during charging or discharging can be further suppressed.

Also, since the electrolytic solution is accommodated in the metal case, the metal case does not expand even if the electrolytic solution volatilizes. Therefore, a highly volatile electrolyte can be used as the electrolyte. Highly volatile electrolytes are difficult to solidify or freeze at low temperatures. Therefore, when an electrolytic solution that is difficult to solidify or freeze at a low temperature is used, an assembled battery having a plurality of metal case-type cells can be used in a low-temperature environment. Therefore, even if an assembled battery having a plurality of metal case type cells is mounted on a saddle-ride type vehicle, charging of the assembled battery or discharging of a large current is performed at a lower temperature than the battery mounted on the automobile. In addition, the deterioration of the metal case type cell can be suppressed. That is, even in an environment where a battery pack mounted on a saddle riding type vehicle is used, deterioration of the metal case type cell (lithium ion cell) due to charging or discharging in a low temperature environment can be suppressed.

As described above, the assembled battery of the present invention can suppress deterioration of the metal case type cell (lithium ion cell) even in an environment where the assembled battery mounted on the saddle riding type vehicle is used.

(2) According to one aspect of the present invention, the assembled battery of the present invention preferably has the following configuration in addition to the configuration of the above (1).
In at least one metal case type cell of the plurality of metal case type cells, the one positive electrode, the one negative electrode, and the electrolytic solution are accommodated in the metal case type cell, and the electrolytic solution is at −20 ° C. It is an electrolyte that does not freeze.

By using an electrolytic solution that does not freeze at −20 ° C. as the electrolytic solution, an assembled battery having a plurality of metal case-type cells can be used in a low temperature environment of about −20 ° C. Therefore, even if an assembled battery having a plurality of metal case cells is mounted on a saddle-ride type vehicle and charged or discharged with a large current at a low temperature of about −20 ° C., the metal case cell ( Deterioration of the lithium ion cell) can be suppressed. Therefore, even if it is the use environment of the assembled battery mounted in the saddle-ride type vehicle, deterioration of a metal case type cell (lithium ion cell) can be suppressed more.

(3) According to one aspect of the present invention, the assembled battery of the present invention preferably has the following configuration in addition to the above configuration (1) or (2). An assembled battery has a housing part which accommodates both the said metal case type cell and the said metal case type cell fixing | fixed part.

According to this configuration, the housing part of the assembled battery accommodates a plurality of metal case type cells and metal case type cell fixing parts. Therefore, a plurality of metal case type cells can be protected from water and moisture. Therefore, deterioration of the metal case type cell (lithium ion cell) can be suppressed. Therefore, even when the assembled battery is mounted on a saddle-ride type vehicle that does not have an engine room or a motor room, deterioration of the metal case type cell (lithium ion cell) can be suppressed. That is, it is possible to further suppress the deterioration of the metal case type cell (lithium ion cell) even in the usage environment of the assembled battery mounted on the saddle riding type vehicle.

(4) According to one aspect of the present invention, the assembled battery of the present invention preferably has the following configuration in addition to the configuration of the above (3). An assembled battery is provided in the housing part in a state accessible from the outside of the housing part, and is electrically connected to at least one positive electrode of at least one metal case type cell of the plurality of metal case type cells. One external positive electrode terminal to be connected and at least one metal case cell provided in the housing portion in a state accessible from the outside of the housing portion and having at least one metal case cell of the plurality of metal case cells And an external negative electrode terminal electrically connected to the negative electrode.

The assembled battery has one external positive terminal and one external negative terminal. The external positive electrode terminal and the external negative electrode terminal are provided in the housing part in a state that can be accessed from the outside of the housing part. Therefore, the external positive terminal and the external negative terminal can be connected to a device that supplies power to the assembled battery or a device that supplies power to the assembled battery.

(5) According to one aspect of the present invention, the assembled battery of the present invention preferably has the following configuration in addition to the configuration of (4) above. The housing part is a box having a plurality of surfaces respectively arranged along a plurality of planes intersecting each other, and the one external positive terminal and the one external negative terminal are both of the plurality of surfaces. Are provided on one surface.

According to this configuration, since the external positive terminal and the external negative terminal are provided on one surface of the housing portion, it is easy to connect the external positive terminal and the external negative terminal to an external device.

(6) According to one aspect of the present invention, the assembled battery of the present invention preferably has the following configuration in addition to any of the above configurations (1) to (5). The plurality of metal case type cells are connected in series in one row. The metal case type cell fixing portion fixes the plurality of metal case type cells in a state of being connected in series in a row.

According to this configuration, the plurality of metal case type cells included in the assembled battery are connected in series in one row. Therefore, the output voltage of the assembled battery is higher than when a plurality of metal case type cells of the same number are connected in series and in parallel. Therefore, the number of metal case-type cells included in the assembled battery can be reduced while securing the output voltage necessary for the assembled battery. Therefore, the assembled battery can be made small and light. This assembled battery can be used in an environment where the output current and capacity required for the assembled battery are relatively small and the output voltage required for the assembled battery is relatively large.

(7) According to one aspect of the present invention, the assembled battery of the present invention preferably has the following configuration in addition to any of the above configurations (1) to (5). The plurality of metal case type cells constitute a plurality of series cell groups including at least two metal case type cells connected in series with each other. The plurality of series cell groups are connected in parallel to each other. The metal case type cell fixing portion fixes a plurality of series cell groups connected in parallel.

According to this configuration, the assembled battery has a plurality of series cell groups. Each of the plurality of series cell groups includes at least two metal case-type cells connected in series with each other. By increasing the number of metal case type cells constituting the series cell group, the output voltage of the assembled battery can be increased. The plurality of series cell groups are connected in parallel to each other. That is, the plurality of metal case type cells included in the assembled battery include metal case type cells connected in parallel to each other. Therefore, the output current of the assembled battery becomes larger than when a plurality of metal case-type cells included in the assembled battery are connected in series in one row. As the output current of the assembled battery increases, the capacity of the assembled battery also increases. As the number of metal case cells connected in parallel with each other increases, the output current and capacity of the assembled battery increase. Since the capacity of the assembled battery is large, the frequency of charging the assembled battery can be reduced. As a result, deterioration of the metal case type cell (lithium ion cell) can be suppressed. This assembled battery can be used in an environment where the output voltage, output current, and capacity required for the assembled battery are relatively large.

(8) According to one aspect of the present invention, the assembled battery of the present invention preferably has the following configuration in addition to any of the above configurations (1) to (5). The plurality of metal case type cells constitute a plurality of parallel cell groups including at least two metal case type cells connected in parallel to each other. The plurality of parallel cell groups are connected in series with each other. The metal case type cell fixing portion fixes a plurality of parallel cell groups connected in series.

According to this configuration, the assembled battery has a plurality of parallel cell groups. The plurality of parallel cell groups are connected in series with each other. By increasing the number of parallel cell groups, the output voltage of the assembled battery can be increased. Each of the plurality of parallel cell groups includes at least two metal case-type cells connected in parallel to each other. That is, the plurality of metal case type cells included in the assembled battery include metal case type cells connected in parallel to each other. Therefore, the output current of the assembled battery becomes larger than when a plurality of metal case-type cells included in the assembled battery are connected in series in one row. As the output current of the assembled battery increases, the capacity of the assembled battery also increases. As the number of metal case cells connected in parallel with each other increases, the output current and capacity of the assembled battery increase. Since the capacity of the assembled battery is large, the frequency of charging the assembled battery can be reduced. As a result, deterioration of the metal case type cell (lithium ion cell) can be suppressed. This assembled battery can be used in an environment where the output voltage, output current, and capacity required for the assembled battery are relatively large.

(9) According to one aspect of the present invention, the assembled battery of the present invention preferably has the following configuration in addition to any of the above configurations (1) to (8). The assembled battery can be charged with a DC charger for 12V to 15V.

Generally, the output voltage of a lead storage battery mounted on a vehicle (including an automobile and a saddle type vehicle) that uses an engine as a drive source is about 12V to 15V. Therefore, the assembled battery can be charged with a DC charger for 12V to 15V, so that the assembled battery can be used in place of a lead storage battery mounted on a vehicle using an engine as a drive source.

(10) According to one aspect of the present invention, the assembled battery of the present invention preferably has the following configuration in addition to any of the above configurations (1) to (9). The assembled battery can be mounted on a straddle-type vehicle including at least one front wheel, at least one rear wheel, and a drive source at least partially disposed behind the at least one front wheel in the vehicle front-rear direction. is there.

<Definition of terms>
In the present invention, "each of the plurality of metal case type cells is connected in series to one of the plurality of metal case type cells" means that each of the plurality of metal case type cells is the same metal case type cell. It is not intended to be connected in series. Each of the plurality of metal case type cells may or may not be connected in series to the same metal case type cell. For example, it is assumed that a plurality of metal case type cells include first to third metal case type cells. It is assumed that the first metal case type cell is connected in series to the second metal case type cell, and the third metal case type cell is connected in series to the fourth metal case type cell. In this case, the first metal case type cell may or may not be connected in series with the third metal case type cell and the fourth metal case type cell.
In the present invention, "each of the plurality of metal case type cells is connected in series to any of the plurality of metal case type cells" means that the metal case in which each of the plurality of metal case type cells is connected in series. It is not intended that the number of type cells be one. The number of metal case type cells to which each of the plurality of metal case type cells is connected in series may be one, or may be two or more.

In the present invention, an “electrolytic solution” is a solution in which an electrolyte is dissolved in a solvent and exists in a liquid form in the cell. The electrolyte that dissolves in the solvent does not include a solid electrolyte. A “solid electrolyte” is an electrolyte that exists in a gel or solid form in a cell.

In the present invention, “carbon” is a substance obtained in a process of generating a substance having a high carbon content by releasing an element other than carbon from a raw material containing carbon. This process is called so-called carbonization. By subjecting the material obtained by carbonization to heat treatment at a high temperature, a laminated structure of carbon layers develops to obtain graphite. Graphite has a laminated structure in which layers having two-dimensionally bonded carbon six-membered rings are laminated, and the interlayer distance in the laminated structure is 3.35 angstroms or less. “Carbon” in the present invention is a substance before reaching graphite. In the present invention, “carbon” does not include graphite.

In the present invention, the “interlayer distance” is a distance between adjacent layers. In the present invention, the “average interlayer distance” is an average value of distances between adjacent layers.

In the present invention, the “electrolyte solution that does not freeze at −20 ° C.” is an electrolyte solution that does not freeze at −20 ° C. under atmospheric pressure. Atmospheric pressure varies with altitude. The “electrolyte solution that does not freeze at −20 ° C.” may be frozen at an altitude of −20 ° C. at an altitude unless it is frozen at −20 ° C. at atmospheric pressure.

In the present invention, the “state in which the external positive terminal can be accessed from the outside of the housing portion” is a state in which the external positive terminal can be electrically connected to a device to which power is supplied from the assembled battery. The “state in which the external negative electrode terminal is accessible from the outside of the housing portion” is a state in which the external negative electrode terminal can be electrically connected to a device that supplies power to the assembled battery.

In the present invention, “one external positive electrode terminal electrically connected to at least one positive electrode included in each of at least one metal case type cell” means any metal included in the assembled battery in one external positive terminal. It refers to a state where it is connected to the at least one positive electrode without using a case cell. The definition of “one external negative electrode terminal electrically connected to at least one negative electrode respectively included in at least one metal case type cell” in the present invention is also the same.

In the present invention, “a plurality of surfaces arranged along a plurality of planes intersecting each other” refers to a state in which the plurality of surfaces are parallel or substantially parallel to the plurality of planes, respectively. Each of the plurality of surfaces may have a gently curved surface or unevenness as long as it is along any plane.

In the present invention, “a plurality of metal case-type cells are connected in series in one row” means that a plurality of metal case-type cells are electrically connected in series in one row. The case type cells may be arranged in a line or may not be arranged in a line.

In the present invention, the “parallel cell group composed of at least two metal case-type cells connected in parallel to each other” includes only at least two metal case-type cells connected in parallel to each other. That is, the metal case type cells constituting the parallel cell group are not connected in series. The metal case type cell which comprises a parallel cell group may be connected in series with the metal case type cell which is not contained in this parallel cell group.

In the present invention, the “series cell group composed of at least two metal case type cells connected in series with each other” includes only at least two metal case type cells connected in series with each other. That is, the metal case type cells constituting the series cell group are not connected in parallel. The metal case type cell which comprises a serial cell group may be connected in parallel with the metal case type cell which is not contained in this serial cell group.

“Saddle-riding vehicle” refers to any vehicle that rides in a state where the rider straddles the saddle. The saddle riding type vehicle in the present invention includes a motorcycle, a motorbike, a moped, a tricycle, and a four-wheel buggy (ATV: All Terrain Vehicle). Motorcycles included in saddle riding type vehicles include scooters, motorbikes, mopeds, and the like.

In the present invention, the “vehicle longitudinal direction” of the saddle riding type vehicle is the longitudinal direction as viewed from the driver when the driver gets on the vehicle standing upright on a horizontal road surface.

In the present invention / specification, at least one (one) of a plurality of options includes all combinations conceivable from the plurality of options. At least one (one) of the plurality of options may be any one of the plurality of options or all of the plurality of options. For example, at least one of A, B and C may be A alone, B alone, C alone, A and B, A and C It may be B, C, A, B, and C.

The assembled battery of the present invention does not specify the number in the scope of claims, and may have a plurality of elements that are displayed in a singular form when translated into English. The assembled battery of the present invention does not specify the number in the scope of claims, and may have only one element that is displayed as a single element when translated into English.

In this specification, for example, a numerical range may be expressed by using “to” or “from” such as “1 to 10” and “1 to 10”. In the present specification, “1 to 10” and “1 to 10” both mean 1 or more and 10 or less.

In the present invention, including, having, having, and their derivatives are used with the intention of including additional items in addition to the listed items and their equivalents. ing.
In the present invention, the terms mounted, connected, coupled, and supported are used in a broad sense. Specifically, it includes not only direct attachment, connection, coupling and support, but also indirect attachment, connection, coupling and support. Further, connected and coupled are not limited to physical or mechanical connections / couplings. They also include direct or indirect electrical connections / couplings.

Unless defined otherwise, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be construed as having a meaning consistent with the meaning in the context of the relevant technology and this disclosure, and are idealized or overly formal It is not interpreted in a sense.

In this specification, the term “preferred” is non-exclusive. “Preferred” means “preferably but not limited to”. In the present specification, the configuration described as “preferable” has at least the above-described effect obtained by the configuration (1). Further, in this specification, the term “may” is non-exclusive. “May” means “may be, but is not limited to”. In the present specification, the configuration described as “may” exhibits at least the above-described effect obtained by the configuration of (1) above.

In the present invention, it is not limited to combine the above-described preferable configurations. Before describing in detail embodiments of the present invention, it is to be understood that the present invention is not limited to the details of the arrangement and arrangement of components set forth in the following description or illustrated in the drawings. The present invention is also possible in embodiments other than those described below. The present invention is also possible in embodiments in which various modifications are made to the embodiments described later. Further, the present invention can be implemented by appropriately combining the modifications described later.

The assembled battery of the present invention can suppress the deterioration of the lithium ion cell even in the usage environment of the assembled battery mounted on the saddle riding type vehicle.

It is a schematic diagram which shows schematic structure of the assembled battery of embodiment of this invention. It is a schematic diagram which shows schematic structure of the assembled battery of the specific example of embodiment of this invention. It is a circuit diagram of the some lithium ion cell which the assembled battery of the specific example of embodiment of this invention has. It is a perspective view which shows the internal structure of a lithium ion cell. It is a model figure of a lithium ion cell. It is a disassembled perspective view of an assembled battery. It is a circuit diagram of the some lithium ion cell which the assembled battery of the example of a change of embodiment of this invention has. It is a graph which shows the discharge characteristic of the lithium ion cell in a 25 degreeC environment. It is a graph which shows the electric current of the lithium ion cell in one cycle deterioration test. It is a graph which shows the initial capacity ratio of a lithium ion cell when a lithium ion cell is preserve | saved under a predetermined temperature environment. It is a graph which shows the initial capacity ratio of the lithium ion cell when charging and discharging are repeated in an environment of 45 ° C., and the initial capacity ratio of the lithium ion cell according to the present invention example and the lithium ion cell according to the comparative example It is a graph which shows together and initial capacity ratio.

<Embodiment of the present invention>
Hereinafter, the assembled battery 16 of the embodiment of the present invention will be described with reference to FIG. The assembled battery 16 has a plurality of metal case-type cells 161 connected to each other. Each of the plurality of metal case type cells 161 is connected in series to one of the plurality of metal case type cells 161. Each of the plurality of metal case type cells 161 may be connected in series to any one of the plurality of metal case type cells 161. Each of the plurality of metal case type cells 161 may be connected in series to two or more metal case type cells 161 among the plurality of metal case type cells 161.

Each of the plurality of metal case type cells 161 includes a positive electrode, a negative electrode, an electrolytic solution or a solid electrolyte, a positive electrode, a negative electrode, and a metal case that houses the electrolytic solution. Type cell. The positive electrode has a positive electrode active material having an olivine structure. The negative electrode includes a negative electrode active material that includes a plurality of carbon layers 16121a, 16121b, and 16121c, and in which an average interlayer distance between the plurality of carbon layers is equal to or greater than a diameter of lithium atoms. FIG. 1 illustrates a case where lithium atoms are present between two adjacent carbon layers 16121a and 16121b. Further, the case where lithium atoms exist between two adjacent carbon layers 16121b and 16121c is illustrated. In FIG. 1, the diameter of the lithium atom is indicated as D. In addition, a distance between two adjacent carbon layers 16121a and 16121b is indicated as L. The distance between two adjacent carbon layers 16121a and 16121b may be referred to as an interlayer distance between the two adjacent carbon layers 16121a and 16121b. FIG. 1 illustrates a case where the distance L between two adjacent carbon layers 16121a and 16121b is larger than the diameter D of lithium atoms.

The assembled battery 16 includes a metal case type cell fixing unit that fixes the plurality of metal case type cells 161 to each other such that each of the plurality of metal case type cells 161 is fixed to the metal case type cells 161 connected in series. Have

According to this configuration, each of the plurality of metal case type cells 161 is connected in series to one of the plurality of metal case type cells 161. As the number of metal case type cells 161 connected in series with each other increases, the output voltage of the assembled battery 16 increases. By increasing the number of metal case type cells 161 connected in series with each other, the assembled battery 16 can be used in a usage environment that requires a high output voltage.

The metal case type cell 161 is a lithium ion cell. Lithium ion cells have lower weight energy density and volumetric energy density than lead acid batteries. Therefore, when the assembled battery 16 having a plurality of lithium ion cells 161 is mounted on the saddle riding type vehicle instead of the lead storage battery, the saddle riding type vehicle can be reduced in weight and size while maintaining the capacity of the battery. Alternatively, the capacity of the battery can be increased without increasing the size and weight of the saddle riding type vehicle. By increasing the capacity of the assembled battery excessively, the burden on each of the plurality of metal case type cells included in the assembled battery is reduced, so that deterioration of the metal case type cell can be suppressed.

Each of the plurality of metal case type cells (lithium ion cells) 161 has one positive electrode, one negative electrode, and an electrolytic solution or a solid electrolyte. The negative electrode of the metal case type cell is a negative electrode active material including a plurality of carbon layers 16121a, 16121b, and 16121c, not a graphite layer, and the average interlayer distance of the plurality of carbon layers is equal to or greater than the diameter of the lithium atom. Includes negative electrode active material.
Since the average interlaminar distance of the plurality of carbon layers is equal to or greater than the diameter of lithium ions, even when lithium ions enter between adjacent carbon layers in the negative electrode, There is almost no gap between them. Further, even when lithium ions come out between adjacent carbon layers during discharge of the metal case cell 161, the distance between adjacent carbon layers does not change much. That is, when the metal case cell 161 is charged and discharged, even if lithium ions enter and exit between the carbon layers, the average interlayer distance between the plurality of carbon layers hardly changes. Therefore, the lamination state of the carbon layer hardly changes. Thereby, the crystal structure of a negative electrode does not change so much. Therefore, deterioration of the negative electrode can be suppressed. Therefore, deterioration of the metal case type cell 161 having this negative electrode can be suppressed. Therefore, deterioration of the metal case cell 161 having this negative electrode can be suppressed. In addition, since the negative electrode has the above-described configuration, deterioration of the metal case cell 161 can be suppressed even when the frequency of charging and discharging of the metal case cell 161 is increased. Furthermore, since the negative electrode has the above-described configuration, the metal case cell 161 having the negative electrode can suppress deterioration even at a low temperature. Therefore, even when the metal case cell 161 is mounted on a saddle-ride type vehicle and the metal case cell 161 is charged and frequently in a low temperature state, the metal case cell (lithium ion cell) 161 is deteriorated. Can be suppressed.

In addition, since the positive electrode of the metal case type cell 161 includes a positive electrode active material having an olivine structure, the metal case type cell (lithium ion cell) is unlikely to deteriorate even when charging and discharging are repeated. Therefore, even if charging and discharging of the metal case cell are repeated in a low temperature environment, the metal case cell (lithium ion cell) 161 is unlikely to deteriorate. Therefore, even if an assembled battery 16 having a plurality of metal case cells 161 is mounted on a saddle-ride type vehicle and charging and discharging of the assembled battery 16 are repeated relatively frequently, a metal case cell (lithium ion cell) ) 161 degradation can be suppressed. That is, deterioration of the metal case type cell (lithium ion cell) 161 can be suppressed even in an environment where the assembled battery 16 mounted on the saddle riding type vehicle is used.
Furthermore, the olivine structure of the positive electrode active material is a hexagonal close-packed charge structure and a stable crystal structure. Therefore, the metal case type cell (lithium ion cell) having the above-described configuration can be used even in a high temperature environment.

In addition, the positive electrode active material has an olivine structure, and further includes a plurality of carbon layers 16121a, 16121b, and 16121c in which the negative electrode active material is laminated, and the average interlayer distance of the plurality of carbon layers is equal to or greater than the diameter of the lithium atom. is there. Therefore, deterioration can be suppressed even in a low temperature state. Therefore, even if this metal case cell 161 is mounted on a saddle-ride type vehicle and the frequency of charging and discharging of the metal case cell 161 is increased in a low temperature state, the metal case cell (lithium ion cell) 161 is deteriorated. It was found that can be suppressed.

Further, when the output current of the metal case type cell (lithium ion cell) 161 increases, the fluctuation range of the SOC of the metal case type cell (lithium ion cell) 161 increases.
It is necessary to increase the capacity of the assembled battery in order to improve the durability of the assembled battery or lengthen the discharge time of the assembled battery while using the assembled battery in a usage situation where the SOC fluctuation range is large. It becomes. One method for increasing the capacity of the assembled battery is to increase the number of metal case cells (lithium ion cells) included in the assembled battery.
However, since the metal case type cell (lithium ion cell) 161 includes the positive electrode and the negative electrode having the above-described configuration, the metal case type cell (lithium ion cell) 161 has a large fluctuation range of SOC. Deterioration of the case type cell (lithium ion cell) 161 can be suppressed. Therefore, even if the assembled battery 16 is used in a usage situation where the fluctuation range of the SOC is large while suppressing the increase in the number of metal case type cells (lithium ion cells) 161 included in the assembled battery 16, the durability of the assembled battery 16 is improved. The discharge time of the assembled battery 16 can be increased. Such an assembled battery 16 can suppress weight and volume. Therefore, handling of the assembled battery 16 becomes easier. Therefore, the assembled battery 16 is easy to be mounted on a saddle riding type vehicle. Moreover, the versatility of the assembled battery 16 is improved.

Furthermore, as described above, the metal case type cell (lithium ion cell) 161 is not easily deteriorated even if the frequency of charging and discharging increases. Therefore, an increase in the number of metal case type cells (lithium ion cells) 161 included in the assembled battery 16 can be suppressed. Thereby, the weight and volume of the assembled battery 16 can be suppressed. Therefore, handling of the assembled battery 16 becomes easier. Therefore, the assembled battery 16 is easy to be mounted on a saddle riding type vehicle. Moreover, the versatility of the assembled battery 16 is improved.

Each of the plurality of metal case type cells 161 is a metal case type cell having one positive electrode, one negative electrode, and a metal case that accommodates an electrolytic solution or a solid electrolyte. The metal case has high heat dissipation. Therefore, when the plurality of metal case cells 161 are charged and discharged, even if the plurality of metal case cells 161 generate heat, each of the plurality of metal case cells 161 dissipates heat. Thereby, the temperature rise of the assembled battery 16 which has the some metal case type cell 161 can be suppressed. Therefore, even if the assembled battery 16 having a plurality of metal case type cells is mounted on a saddle riding type vehicle and the assembled battery 16 is discharged with a large current, the temperature rise of the assembled battery 16 is suppressed. Can do. As a result, deterioration of the metal case type cell (lithium ion cell) 161 can be suppressed. That is, deterioration of the metal case type cell (lithium ion cell) 161 due to heat generation during charging or discharging can be suppressed even in the usage environment of the assembled battery 16 mounted on the saddle riding type vehicle.

Furthermore, the plurality of metal case type cells 161 are fixed to each other by the metal case type cell fixing portion 163. Therefore, the position of the plurality of metal case cells 161 can be maintained with a layout that takes into consideration the heat dissipation of the metal case cells 161. For example, it can be maintained in a state where an appropriate gap is left between the metal case type cells 161. Thereby, when the plurality of metal case cells 161 are charged and discharged, even if the plurality of metal case cells 161 generate heat, the temperature rise of the assembled battery 16 can be suppressed. Therefore, even if the assembled battery 16 having a plurality of metal case type cells 161 is mounted on a saddle riding type vehicle and the assembled battery 16 is discharged with a large current, the temperature rise of the assembled battery 16 is further suppressed. can do. As a result, deterioration of the metal case type cell (lithium ion cell) 161 can be further suppressed. That is, even in an environment where the assembled battery 16 mounted on the saddle riding type vehicle is used, deterioration of the metal case type cell (lithium ion cell) 161 due to heat generation during charging or discharging can be further suppressed.

Also, since the electrolytic solution is accommodated in the metal case, the metal case does not expand even if the electrolytic solution volatilizes. Therefore, a highly volatile electrolyte can be used as the electrolyte. Highly volatile electrolytes are difficult to solidify or freeze at low temperatures. Therefore, when an electrolytic solution that is difficult to solidify or freeze at a low temperature is used, the assembled battery 16 having a plurality of metal case type cells 161 can be used in a low temperature environment. Therefore, even if the assembled battery 16 having a plurality of metal case-type cells 161 is mounted on a saddle-ride type vehicle, charging of the assembled battery 16 or discharging of a large current is performed at a lower temperature than the battery mounted on the automobile. Even if performed, the deterioration of the metal case type cell 161 can be suppressed. That is, even in an environment where the assembled battery 16 mounted on the saddle riding type vehicle is used, deterioration of the metal case type cell (lithium ion cell) 161 due to charging or discharging in a low temperature environment can be suppressed.

<Specific Examples of Embodiments of the Present Invention>
Next, a specific example of the assembled battery 16 according to the embodiment of the present invention will be described with reference to FIGS. Basically, specific examples of embodiments of the present invention have all the features of the embodiments of the present invention described above. Elements that are the same as or correspond to those in the above-described embodiment are assigned the same reference numerals, and description of those elements will not be repeated.

As shown in FIG. 2, the assembled battery 16 is mounted on the saddle riding type vehicle 1. The assembled battery 16 is detachable from the saddle riding type vehicle 1. The assembled battery 16 may be mounted on the saddle riding type vehicle 1 on which a lead storage battery can be mounted instead of the lead storage battery. The saddle riding type vehicle 1 is, for example, a motorcycle. The saddle riding type vehicle 1 includes at least one front wheel 2 and at least one rear wheel 3. The saddle riding type vehicle 1 includes a seat on which a rider is seated. At least a part of the seat is disposed behind all the front wheels 2 in the vehicle longitudinal direction. The saddle riding type vehicle 1 includes an engine 10 as a vehicle drive source and a starter motor 11. At least a part of the engine may be arranged behind all the front wheels 2 in the vehicle longitudinal direction. The starter motor rotates the crankshaft of the engine when the engine is started. The straddle-type vehicle 1 using an engine as a drive source may have a generator with a motor function (ISG: Integrated Starter Generator) instead of having a starter motor. The starter motor and the ISG do not correspond to the drive source in the present invention.

The assembled battery 16 supplies power to electrical components (power consumption devices) of the saddle riding type vehicle 1. The electrical component includes a starter motor. The electrical component may include, for example, a control device, a meter, a horn, a light, various sensors, a seat heater, and the like.

The assembled battery 16 includes a plurality of metal case type cells 161, a housing part 162, a metal case type cell fixing part 163, one external positive terminal 166, and one external negative terminal 167. The number of metal case type cells 161 included in the assembled battery 16 is not particularly limited.

Each of the plurality of metal case type cells 161 is a lithium ion cell. The plurality of metal case type cells 161 are electrically connected to each other. The number of the metal case type cells 16 included in the assembled battery 16 is not particularly limited. Each of the plurality of metal case type cells 161 is connected in series to one of the plurality of metal case type cells 161. The number of metal case type cells 161 connected in series with each other is not particularly limited. In FIG. 2, at least four metal case type cells 16 are connected in series. The plurality of metal case type cells 161 may include a plurality of metal case type cells 161 connected in parallel. The number of metal case type cells 161 connected in parallel with each other is not particularly limited.

The metal case type cell fixing portion 163 fixes the plurality of metal case type cells 161 to each other. Thereby, the plurality of metal case type cells 161 are integrated. For example, the adjacent metal case type cells 161 may be fixed by the metal case type cell fixing portion 163. For example, the metal case type cells 161 that are not adjacent to each other may be fixed. The aspect in which the metal case type cell fixing portion 163 fixes the plurality of metal case type cells 161 to each other is not limited to this aspect.

In a state in which the plurality of metal case type cells 161 are fixed to the metal case type cell fixing portion 163, a space may be formed between adjacent metal case type cells 161, and no space is formed. Also good.

The external positive terminal 166 and the external negative terminal 167 are provided in the housing part 162 in a state where they can be accessed from the outside of the housing part 162. The external positive electrode terminal 166 is electrically connected to at least one positive electrode included in at least one metal case type cell 161 among the plurality of metal case type cells 161. The external negative electrode terminal 167 is electrically connected to at least one negative electrode included in at least one metal case cell 161 of the plurality of metal case cells 161.

The external positive terminal 166 and the external negative terminal 167 may be connected as follows.
The external positive terminal 166 and the external negative terminal 167 are connected to electrical components (such as the starter motor 11) of the saddle riding type vehicle 1. The external positive terminal 166 and the external negative terminal 167 may also be connected to the power circuit of the saddle riding type vehicle 1. In this case, the electrical component and the power supply circuit are connected in parallel. The power supply circuit of the saddle riding type vehicle 1 may be a power supply circuit for 12V to 15V, for example. The power supply circuit may include, for example, an AC generator and a regulated rectifier.

When charging the assembled battery 16, the external positive terminal 166 and the external negative terminal 167 are connected to a DC charger that supplies power to the assembled battery 16. The DC charger is a DC charger for 12V to 15V, for example. The assembled battery 16 may be charged while being mounted on the saddle riding type vehicle 1 or may be charged while being removed from the saddle riding type vehicle 1.

The assembled battery 16 may include a battery management device (BMS: Battery Management System) that manages a plurality of metal case type cells 161. The battery management device monitors the charging and discharging of the plurality of metal case cells 161 and monitors the charging and discharging of the plurality of metal case cells 161.

FIG. 3 shows an example of a connection mode of the plurality of metal case type cells 161. The plurality of metal case type cells 161 constitutes a plurality of parallel cell groups 171 including a plurality of metal case type cells 161 connected in parallel to each other. The plurality of parallel cell groups 171 are connected to each other in series.

The plurality of metal case type cells 161 have the same configuration. FIG. 4 is a perspective view showing an internal structure of an example of the metal case type cell 161. As shown in FIG. 4, the metal case type cell 161 has one positive electrode 1611, one negative electrode 1612, and a metal case 1613. In the following description, the metal case 1613 is referred to as a metal case 1613. The positive electrode 1611 and the negative electrode 1612 are accommodated in a metal case 1613. The metal case 1613 has a sealing property. The material of the metal case 1613 is not particularly limited as long as it is a metal. As the metal case 1613, for example, a steel plate with nickel plating may be used. In the example shown in FIG. 4, the metal case 1613 has a cylindrical shape.

In the example shown in FIG. 4, the positive electrode 1611 and the negative electrode 1612 are accommodated in the metal case 1613 in a state of being wound around a predetermined axis. In the example shown in FIG. 4, the predetermined axis is the central axis of the metal case 1613. A separator 1614 is disposed between the positive electrode 1611 and the negative electrode 1612. The separator 1614 is wound around a predetermined axis together with the positive electrode 1611 and the negative electrode 1612. In the metal case 1613, the positive electrode 1611, the negative electrode 1612, and the separator 1614 are immersed in an electrolytic solution 1615 (see FIG. 5). As described above, the metal case 1613 accommodates the positive electrode 1611, the negative electrode 1612, the electrolytic solution 1615, and the separator 1614.

The structure of the metal case type cell 161 will be further described with reference to FIG. FIG. 5 is a model diagram of the metal case type cell 161.

The positive electrode 1611 includes a positive electrode active material 16111 and a current collector 16112. The positive electrode active material 16111 has an olivine structure. The positive electrode active material is, for example, lithium iron phosphate or lithium manganese phosphate.

The negative electrode 1612 includes a negative electrode active material 16121 and a current collector 16122. The negative electrode active material 16121 includes a plurality of carbon layers 16121a and 16121b. The negative electrode active material 16121 may contain a substance other than carbon. The negative electrode active material may contain a silicon oxide, for example. A plurality of carbon layers 16121a and 16121b may contain substances other than carbon. The negative electrode active material 16121 may include at least one of hard carbon and soft carbon, for example. In the negative electrode active material 16121, the average distance between two adjacent carbon layers (eg, the layer 16121a and the layer 16121b) is equal to or greater than the diameter of the lithium atom. In FIG. 5, the diameter of the lithium atom is indicated as D. In addition, a distance between two adjacent carbon layers 16121a and 16121b is indicated as L. The distance between the two adjacent carbon layers 16121a and 16121b may be referred to as an interlayer distance between the two adjacent carbon layers 16121a and 16121b. FIG. 5 illustrates a case where the distance L between two adjacent carbon layers 16121a and 16121b is larger than the diameter D of the lithium atoms.

A carbon source is used for manufacturing the negative electrode active material 16121. The carbon source is not particularly limited, but considering the yield, a compound containing a large amount of carbon is preferable. Examples of the compound containing a large amount of carbon include petroleum-derived substances such as petroleum pitch and coke, and plant-derived substances such as coconut shells. Carbon is classified into non-graphitizable carbon (hard carbon) and graphitizable carbon (soft carbon) depending on the starting material. As the carbon source, non-graphitizable carbon may be used, graphitizable carbon may be used, and both non-graphitizable carbon and graphitizable carbon may be used. In an inert atmosphere, carbon is graphitized by baking the carbon at a high temperature. Graphite has a structure in which thin layers of carbon (carbon) are stacked. A thin layer in which six-membered rings of carbon are two-dimensionally bonded is sometimes referred to as graphene. The temperature at which carbon graphitizes is about 2500 ° C. or higher and 3000 ° C. or lower. The higher the baking temperature and the longer the baking time, the smaller the distance between adjacent carbons (interlayer distance) in the laminated carbon layer, and the size of the carbon layer, in other words, the crystal The size of the child increases. As a result, so-called crystallinity increases. Graphite refers to a structure in which layers having two-dimensionally bonded carbon six-membered rings are crystallized to have an interlayer distance of 3.35 angstroms or less.
In a structure in which layers in which carbon six-membered rings are two-dimensionally bonded are stacked, the average interlayer distance is less than the diameter of lithium atoms. Therefore, in the negative electrode active material having a plurality of carbon layers, when the average interlayer distance between the plurality of carbon layers is equal to or greater than the diameter of the lithium atom, the negative electrode active material is different from graphite.

The separator 1614 is a porous film. The separator 1614 is made of, for example, polyethylene.

The electrolytic solution 1615 may be, for example, an organic electrolytic solution in which a lithium salt is dissolved in an organic solvent. The organic solvent is, for example, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, or ethyl methyl carbonate. Examples of the lithium salt include lithium hexafluorophosphate, lithium borofluoride, and lithium perchlorate. The electrolytic solution may be gelled by adding a polymer to the organic electrolytic solution. Examples of the polymer include polyethylene oxide, polypropylene oxide, and polyvinylidene fluoride.

The electrolytic solution 1615 may be an electrolytic solution that is difficult to solidify or freeze at a low temperature. For example, the electrolytic solution 1615 may be an electrolytic solution that does not freeze at −20 ° C. Examples of the solvent of the electrolytic solution that does not freeze at −20 ° C. include ethyl acetate, methyl acetate, and acetonitrile.

A more specific structure of an example of the assembled battery 16 will be described with reference to FIG. FIG. 6 is an exploded perspective view of an example of the assembled battery 16. In addition, in order to make the internal structure of the assembled battery 16 easy to understand, FIG. 6 shows an example in which the assembled battery 16 includes 16 metal case type cells 161. Hereinafter, the structure of the assembled battery 16 will be described using the vertical direction of the drawing sheet of FIG. The assembled battery 16 mounted on the saddle riding type vehicle 1 may be installed so that the vertical direction of the paper surface of FIG. 6 is the vertical direction (vertical direction). The direction of the assembled battery 16 mounted on the saddle riding type vehicle 1 is not limited to this.

The housing part 162 includes a main body 1621 and a lid 1622. The main body 1621 and the lid 1622 are separable. The lid 1622 covers the opening formed in the main body 1621. The lid 1622 is provided with one external positive terminal 166 and one external negative terminal 167.

The housing part 162 is a box. In the example shown in FIG. 6, the housing part 162 is a substantially rectangular parallelepiped box. The housing part 162 has an upper surface 162a, a lower surface 162b, and four side surfaces 162c, 162d, 162e, 162f. Since the housing part 162 has a substantially rectangular parallelepiped shape, the housing part 162 has three surfaces respectively arranged along three planes intersecting each other. For example, the upper surface 162a, the side surface 162c, and the side surface 162f are arranged along three planes that intersect each other.

Both the external positive terminal 166 and the external negative terminal 167 are provided on the upper surface 162a. That is, both the external positive terminal 166 and the external negative terminal 167 are provided on one of the six surfaces of the housing portion 162. In other words, both the external positive electrode terminal 166 and the external negative electrode terminal 167 are provided on one surface among three surfaces respectively arranged along three planes intersecting each other. The external positive terminal 166 and the external negative terminal 167 may be provided on a surface other than the upper surface 162a. The external positive terminal 166 and the external negative terminal 167 may be provided on any one of the lower surface 162b and the four side surfaces 162c, 162d, 162e, and 162f. Since the external positive electrode terminal 166 and the external negative electrode terminal 167 are provided on one surface of the housing portion 162, the operation of connecting the external positive electrode terminal 166 and the external negative electrode terminal 167 to the power circuit of the saddle riding type vehicle 1 or the like Easy to connect to a DC charger.

The housing part 162 accommodates 16 metal case type cells 161, a metal case type cell fixing part 163, a connection part 164, and a balance circuit 165. The housing part 162 may accommodate the battery management device described above. For example, the battery management device may be attached to the lid 1622. Note that the battery management device may not be accommodated in the housing portion 162. Only a part of the battery management device may be accommodated in the housing portion 162. The battery management device may be disposed outside the housing portion 162.

The metal case type cell fixing part 163 has two metal case type cell fixing plates 1631 and 1632. The metal case type cell fixing plate 1631 is a plate-like member in which 16 holes 1631a are formed. The metal case type cell fixing plate 1632 is a plate-like member in which 16 holes 1632a are formed. The two metal case cell fixing plates 1631 and 1632 are arranged on both sides of the 16 metal case cells 161. One end portions of the 16 metal case type cells 161 are inserted into the 16 holes 1631a of the metal case type cell fixing plate 1631, respectively. The other end portions of the 16 metal case type cells 161 are inserted into the 16 holes 1632a of the metal case type cell fixing plate 1632, respectively. Thereby, the metal case type cell fixing | fixed part 163 fixes the 16 metal case type cells 161 to each other. In the state where the 16 metal case type cells 161 are fixed to the metal case type cell fixing portion 163, a space is formed between the adjacent metal case type cells 161. The metal case type cell fixing part 163 is not electrically connected to the plurality of lithium ion cells 161.

The 16 metal case type cells 161 are arranged in four rows. That is, each column is composed of four metal case type cells 161. Each of the four metal case type cells 161 constituting the first row has a positive electrode terminal at the lower end thereof. Each of the four metal case type cells 161 constituting the first row has a negative electrode terminal at the upper end thereof. Each of the four metal case type cells 161 constituting the second row has a positive electrode terminal at the upper end thereof. Each of the four metal case type cells 161 constituting the second row has a negative electrode terminal at the lower end thereof. Each of the four metal case type cells 161 constituting the third row has a positive electrode terminal at the lower end thereof. Each of the four metal case-type cells 161 constituting the third row has a negative electrode terminal at the upper end. Each of the four metal case type cells 161 constituting the fourth row has a positive electrode terminal at the upper end thereof. Each of the four metal case type cells 161 constituting the fourth row has a negative electrode terminal at the lower end thereof.

The connection unit 164 includes five connection plates 1641, 1642, 1643, 1644, 1645. The connection plates 1641, 1642, 1643, 1644, 1645 are formed of a conductive material. The connection plate 1641 is connected to the negative terminals of the four metal case-type cells 161 constituting the first row. The connection plate 1642 is connected to the positive terminals of the four metal case-type cells 161 constituting the first row. Furthermore, the connection plate 1642 is connected to the negative terminals of the four metal case type cells 161 constituting the second row. The connection plate 1643 is connected to the positive terminals of the four metal case type cells 161 constituting the second row. Further, the connection plate 1643 connects the negative terminals of the four metal case-type cells 161 constituting the third row. The connection plate 1644 is connected to the positive terminals of the four metal case type cells 161 constituting the third row. Further, the connection plate 1644 is connected to the negative terminals of the four metal case-type cells 161 constituting the fourth row. The connection plate 1645 is connected to the positive terminals of the four metal case type cells 161 constituting the fourth row.

The four metal case type cells 161 in the first row are connected to each other in parallel by a connection plate 1641 and a connection plate 1642. Thus, the four metal case type cells 161 in the first row constitute a parallel cell group 1711 connected in parallel to each other. The four metal case type cells 161 in the second row are connected to each other in parallel by a connection plate 1642 and a connection plate 1643. Thus, the four metal case type cells 161 in the second row constitute a parallel cell group 1712 connected in parallel to each other. The four metal case cells 161 in the third row are connected to each other in parallel by a connection plate 1643 and a connection plate 1644. Thereby, the four metal case type cells 161 in the third row constitute a parallel cell group 1713 connected in parallel to each other. The four metal case type cells 161 in the fourth row are connected to each other in parallel by a connection plate 1644 and a connection plate 1645. Thereby, the four metal case type cells 161 in the fourth row constitute a parallel cell group 1714 connected in parallel to each other.

The four metal case cells 161 in the first row and the four metal case cells 161 in the second row are connected in series by a connection plate 1642. In other words, the parallel cell group 1711 and the parallel cell group 1712 are connected in series by the connection plate 1642. The four metal case cells 161 in the second row and the four metal case cells 161 in the third row are connected in series by a connection plate 1643. In other words, the parallel cell group 1712 and the parallel cell group 1713 are connected in series by the connection plate 1643. The four metal case cells 161 in the third row and the four metal case cells 161 in the fourth row are connected in series by a connection plate 1644. In other words, the parallel cell group 1713 and the parallel cell group 1714 are connected in series by the connection plate 1644. Accordingly, the four parallel cell groups 1711, 1712, 1713, and 1714 are connected in series with each other. The metal case type cell fixing portion 163 fixes four parallel cell groups 1711, 1712, 1713, and 1714 connected in series.

The connection plate 1641 is connected to the external negative terminal 167 through a cable (not shown). As a result, the negative terminals of the four metal case cells 161 in the first row are electrically connected to the external negative terminal 167. Connection plate 1645 is connected to external positive electrode terminal 166 via a cable (not shown). As a result, the positive terminals of the four metal case type cells 161 in the fourth row are electrically connected to the external positive terminal 166.

The balance circuit 165 suppresses variations in the progress of charging of the 16 metal case type cells 161. Generally, when a plurality of cells connected in series are charged, the voltages of the plurality of cells may vary. Thereby, variation may occur in the progress of charging of a plurality of cells. For example, the balance circuit 165 reduces the voltage variation of the metal case type cell 161 by releasing the current of the metal case type cell 161 to the resistance for each metal case type cell 161. The assembled battery 16 may not have the balance circuit 165.

The specific example of the embodiment of the present invention has the following effect in addition to the effect of the embodiment of the present invention described above.

When the electrolytic solution 1615 is accommodated in the metal case 1613, the metal case 1613 does not expand even if the electrolytic solution 1615 volatilizes. Therefore, a highly volatile electrolyte solution can be used as the electrolyte solution 1615. Highly volatile electrolytes are difficult to solidify or freeze at low temperatures. Therefore, when an electrolytic solution that is difficult to solidify or freeze at a low temperature is used, the assembled battery 16 having a plurality of metal case type cells 161 can be used in a low temperature environment. Therefore, even if the assembled battery 16 having a plurality of metal case-type cells 161 is mounted on a saddle-ride type vehicle, charging of the assembled battery or discharging of a large current is performed at a temperature lower than that of the battery mounted on the automobile. However, the deterioration of the metal case type cell can be suppressed. That is, even in an environment where a battery pack mounted on a saddle riding type vehicle is used, deterioration of the metal case type cell (lithium ion cell) due to charging or discharging in a low temperature environment can be suppressed.

By using an electrolytic solution that does not freeze at −20 ° C. as the electrolytic solution, the assembled battery 16 having a plurality of metal case type cells 161 can be used in a low temperature environment of about −20 ° C. Therefore, even if the assembled battery 16 having a plurality of metal case type cells 161 is mounted on the saddle riding type vehicle 1 and charged or discharged with a large current at a low temperature of about −20 ° C., the metal case Deterioration of the type cell 161 can be suppressed. Therefore, even if it is the use environment of the assembled battery 16 mounted in the saddle riding type vehicle 1, the deterioration of the metal case type cell 161 can be further suppressed.

Both the plurality of metal case type cells 161 and the metal case type cell fixing part 163 are accommodated in the housing part 162. Thereby, the plurality of metal case type cells 161 can be protected from water and moisture. Therefore, deterioration of the metal case type cell 161 can be suppressed. Therefore, even when the assembled battery 16 is mounted on the saddle riding type vehicle 1 having no engine room or motor room, the deterioration of the metal case type cell 161 can be suppressed. That is, even in an environment where the assembled battery mounted on the saddle riding type vehicle 1 is used, deterioration of the metal case type cell 161 can be further suppressed.

Also, it is easy to move the plurality of metal case type cells 161 and the metal case type cell fixing part 163 together. Therefore, handling of the assembled battery 16 becomes easier. Therefore, the assembled battery 16 is easy to be mounted on the saddle riding type vehicle 1. Moreover, the versatility of the assembled battery 16 is improved.

The plurality of parallel cell groups 171 are connected in series with each other. By increasing the number of parallel cell groups 171, the output voltage of the assembled battery 16 can be increased. Each of the plurality of parallel cell groups 171 includes at least two metal case type cells 161 connected in parallel to each other. That is, the plurality of metal case type cells included in the assembled battery 16 include metal case type cells 161 connected in parallel to each other. Therefore, the output current of the assembled battery 16 becomes larger than when a plurality of metal case type cells 161 included in the assembled battery 16 are connected in series in one row. As the output current of the assembled battery 16 increases, the capacity of the assembled battery 16 also increases. As the number of metal case cells 161 connected in parallel with each other increases, the output current and capacity of the assembled battery 16 increase. Since the capacity of the assembled battery 16 is large, the frequency of charging the assembled battery 16 can be reduced. As a result, deterioration of the metal case type cell 161 can be suppressed. The assembled battery 16 can be used in an environment where the output voltage, output current, and capacity required for the assembled battery 16 are relatively large.

A plurality of metal case type cells 161 are fixed to each other by the metal case type cell fixing portion 163. Thereby, it is easy to move a plurality of metal case type cells 161 together. Therefore, handling of the assembled battery 16 becomes easy.
In addition, a space is formed between adjacent metal case type cells 161. As a result, heat generated during charging and discharging of the plurality of metal case cells 161 can be moved to this space. In addition, since the metal case 1613 of the metal case type cell 161 is made of metal, the metal case type cell 161 has high heat dissipation. Accordingly, the temperature rise of the plurality of metal case cells 161 can be suppressed when the plurality of metal case cells 161 are charged and discharged.

<Modification of Embodiment of the Present Invention>
The present invention is not limited to the above-described embodiment and specific examples of the embodiment, and various modifications are possible as long as they are described in the claims. Hereinafter, a modified example of the embodiment of the present invention will be described. In addition, about what has the same structure as the structure mentioned above, the description is abbreviate | omitted suitably using the same code | symbol. Specific examples of the above-described embodiment and modifications described later can be implemented in appropriate combination.

◆ Modification example of connection mode of a plurality of metal case type cells In the specific example of the above embodiment, the connection mode of the plurality of metal case type cells 161 is a parallel configuration including at least two metal case type cells 161 connected in parallel to each other. In this embodiment, a plurality of cell groups 171 are connected in series. However, the connection mode of the plurality of metal case type cells of the present invention is not limited to this mode. In the connection mode of the plurality of metal case type cells of the present invention, each of the plurality of metal case type cells may be connected in series to one of the plurality of metal case type cells. When a plurality of metal case type cells of the present invention constitute a plurality of parallel cell groups, the number of parallel cell groups is not particularly limited.

The connection mode of the plurality of metal case type cells of the present invention may be a mode in which a plurality of metal case type cells are connected in series in one row. When the plurality of metal case type cells are connected in series in one row, the output voltage of the assembled battery becomes higher than when the same number of metal case type cells are connected in series and in parallel. Therefore, the number of metal case-type cells included in the assembled battery can be reduced while securing the output voltage necessary for the assembled battery. Therefore, the assembled battery can be made small and light. This assembled battery can be used in an environment where the output current and capacity required for the assembled battery are relatively small and the output voltage required for the assembled battery is relatively large.

The connection mode of the plurality of metal case type cells of the present invention may be a mode in which a plurality of series cell groups composed of at least two metal case type cells connected in series with each other are connected in parallel. An example is shown in FIG. Reference numeral 172 in FIG. 7 indicates a series cell group. When a plurality of metal case type cells of the present invention constitute a plurality of series cell groups, the number of series cell groups is not particularly limited. By increasing the number of metal case type cells constituting the series cell group, the output voltage of the assembled battery can be increased. The plurality of series cell groups are connected in parallel to each other. That is, the plurality of metal case type cells included in the assembled battery include metal case type cells connected in parallel to each other. Therefore, the output current of the assembled battery becomes larger than when a plurality of metal case-type cells included in the assembled battery are connected in series in one row. As the output current of the assembled battery increases, the capacity of the assembled battery also increases. As the number of metal case cells connected in parallel with each other increases, the output current and capacity of the assembled battery increase. Since the capacity of the assembled battery is large, the frequency of charging the assembled battery can be reduced. As a result, deterioration of the metal case type cell (lithium ion cell) can be suppressed. This assembled battery can be used in an environment where the output voltage, output current, and capacity required for the assembled battery are relatively large.

The connection mode of the plurality of metal case-type cells of the present invention is a series connection of a plurality of series-parallel groups obtained by connecting a plurality of series cell groups composed of at least two metal case-type cells connected in series. The aspect connected to may be sufficient.
The connection mode of a plurality of metal case type cells according to the present invention is a plurality of parallel series groups obtained by connecting a plurality of parallel cell groups composed of at least two metal case type cells connected in parallel to each other in series. The aspect connected to may be sufficient.
The connection mode of the plurality of metal case type cells of the present invention is that a plurality of parallel parallel groups obtained by connecting in parallel a plurality of parallel cell groups composed of at least two metal case type cells connected in parallel to each other are connected in series. A connected aspect may be used.
The plurality of metal case type cells may include metal case type cells that are connected only in series to other metal case type cells included in the assembled battery. The plurality of metal case type cells may include metal case type cells that are connected only in parallel to other metal case type cells included in the assembled battery.

In the connection mode of a plurality of metal case cells of the present invention, the number of metal case cells connected in series is not limited. In the aspect of connecting the plurality of metal case type cells of the present invention in series, the number of metal case type cells connected in parallel to each other is not limited.
In the connection mode of a plurality of metal case cells of the present invention, the number of metal case cells connected in series may be the same or different. For example, when a plurality of metal case type cells have two series cell groups, the number of metal case type cells constituting the first series cell group is equal to the number of metal case type cells constituting the second series cell group. It may be the same as the number or different.
In the connection mode of a plurality of metal case cells of the present invention, the number of metal case cells connected in parallel may be the same or different. For example, when a plurality of metal case type cells have two parallel cell groups, the number of metal case type cells constituting the first parallel cell group is equal to the number of metal case type cells constituting the second parallel cell group. It may be the same as the number or different.

Modification Example Related to Metal Case Type Fixing Unit The metal case type cell fixing unit 163 of the specific example of the above embodiment has two metal case type cell fixing plates 1631 and 1632. However, the configuration of the metal case type cell fixing portion is not limited to this mode. For example, the metal case type cell fixing part may be constituted by one plate-like member. The metal case type cell fixing portion may be configured by only one of the metal case type cell fixing plates 1631 and 1632. Further, the metal case type cell fixing portion may be composed of two or more plate-like members. The metal case type cell fixing portion may not be a plate-like member.

In the specific example of the above embodiment, one end portions of the plurality of metal case type cells 161 are inserted into the 16 holes 1631a of the metal case type cell fixing plate 1631, respectively. The other end portions of the plurality of metal case type cells 161 are respectively inserted into the 16 holes 1632a of the metal case type cell fixing plate 1632. Thereby, the plurality of metal case type cells 161 are fixed to each other. However, the aspect which fixes a some metal case type cell mutually by a metal case type cell fixing | fixed part is not limited to this aspect. Further, for example, the plurality of metal case type cells may be fixed to each other by fitting the plurality of metal case type cells respectively into the plurality of grooves (concave portions) formed in the metal case type cell fixing portion.

In the specific example of the above embodiment, the metal case type cells 161 are fixed to each other in a state where a space is formed between the adjacent metal case type cells 161. However, in the present invention, the aspect in which the plurality of metal case type cells are fixed to each other by the metal case type cell fixing portion is not limited to this aspect. The plurality of metal case type cells may be fixed to each other in a state in which no space is formed between at least two of the plurality of metal case type cells.

In the specific example of the above embodiment, the metal case type cell fixing portion 163 is not electrically connected to the plurality of metal case type cells. However, in the present invention, the metal case type cell fixing part may also serve as a connection part for electrically connecting a plurality of metal case type cells to each other. Thereby, the number of parts can be reduced. As a result, the assembled battery can be reduced in weight and size. On the other hand, when the metal case type cell fixing part is provided separately from the connection part, a plurality of metal case type cells are fixed to each other by the metal case type cell fixing part, and then the connection part is electrically connected to the metal case type cell. Can connect. Therefore, it is easy to connect the metal case type cell and the connection portion.

Modification Example Related to Housing Part In the assembled battery 16 of the specific example of the above embodiment, a plurality of metal case type cells 161 and metal case type cell fixing parts 163 are accommodated in the housing part 162. However, in the present invention, the mode of the assembled battery is not limited to this mode. The plurality of metal case type cells and the metal case type cell fixing portion may not be accommodated in the housing portion. Of the plurality of metal case type cells, some of the metal case type cells may be accommodated in the housing portion, and the remaining metal case type cells may not be accommodated in the housing portion. A part of the metal case type cell fixing part may be accommodated in the housing part, and the other part of the metal case type cell fixing part may not be accommodated in the housing part. The plurality of metal case type cells and the metal case type cell fixing portion may be accommodated in the plurality of housing portions. For example, some of the metal case type cells may be accommodated in the first housing part, and the remaining metal case type cells may be accommodated in the second housing part.

The housing portion 162 of the specific example of the above embodiment includes a main body 1621 and a lid 1622. The main body 1621 and the lid 1622 are separable. However, the aspect of the housing part in the present invention is not limited to this aspect. The main body and the lid of the housing part may not be separable. The housing part may be composed of three or more parts.

In the specific example of the above embodiment, the housing portion 162 of the assembled battery 16 is a substantially rectangular parallelepiped box. However, in the present invention, the housing portion of the assembled battery may be a polyhedral box other than a rectangular parallelepiped. Also in that case, the housing part has a plurality of surfaces respectively arranged along a plurality of planes intersecting each other. When the box is a polyhedron other than a rectangular parallelepiped, the number of the faces is at least four.

Example of Modification of Configuration of Plural Metal Case Type Cells In the present invention, the shape of the metal case 1613 is a cylindrical shape. However, the shape of the metal case is not limited to a cylindrical shape. For example, the metal case may have a box shape (cuboid shape). For example, the positive electrode and the negative electrode may be accommodated in a box-shaped metal case in a state where the positive electrode and the negative electrode are wound around a predetermined axis. The metal case may be a flat board. For example, the positive electrode and the negative electrode may be accommodated in a flat board-like metal case in a flat state. For example, a positive and negative electrodes of a metal case type cell may be laminated on a flat board-shaped metal case. For example, a flat board-shaped metal case may be accommodated in a state where the positive electrode and the negative electrode of the metal case cell are wound around a predetermined axis.

In the specific example of the above embodiment, each of the plurality of metal case cells 161 includes a positive electrode 1611, a negative electrode 1612, and an electrolytic solution 1615. However, in the present invention, the metal case type cell may be a metal case type cell having a positive electrode, a negative electrode, and a solid electrolyte. In this case, the solid electrolyte is in contact with both the positive electrode and the negative electrode. The metal case type cell of the present invention may be a metal case type cell in which a positive electrode, a negative electrode, and a solid electrolyte are accommodated in a metal case.
Further, the plurality of lithium ion cells 161 may include a metal case type cell having a positive electrode, a negative electrode and an electrolyte, and a metal case type cell having a positive electrode, a negative electrode and a solid electrolyte.

In the specific example of the above embodiment, the plurality of metal case type cells 161 have the same configuration. However, in the present invention, the plurality of lithium ion cells may include at least two lithium ion cells having different configurations. That is, the plurality of lithium ion cells may include two or more types of lithium ion cells.

In the specific example of the above embodiment, the positive electrode active materials included in the plurality of metal case type cells 161 are the same type. However, in the present invention, the positive electrode active materials included in at least two of the plurality of metal case type cells may be different from each other. That is, two or more kinds of positive electrode active materials included in the plurality of metal case type cells may be used.

In the specific example of the above embodiment, the negative electrode active materials included in the plurality of metal case type cells 161 are the same type. However, in the present invention, the negative electrode active materials included in at least two of the plurality of metal case type cells may be different from each other. That is, two or more types of negative electrode active materials may be included in the plurality of metal case type cells. For example, in the negative electrodes of at least two of the plurality of metal case cells, the average interlayer distance between the plurality of carbon layers may be different from each other.

In the specific example of the above-described embodiment, the electrolyte solutions included in the plurality of metal case type cells 161 are of the same type. However, in the present invention, the electrolyte solutions included in at least two of the plurality of metal case type cells may be different from each other. That is, two or more types of electrolytes may be included in the plurality of metal case type cells. In addition, when the plurality of metal case type cells include the positive electrode, the negative electrode, and the solid electrolyte, the solid electrolytes included in the plurality of metal case type cells may be of the same type. Moreover, the solid electrolyte which at least 2 metal case type cell of several metal case type cells has may mutually differ. That is, two or more types of solid electrolytes may be included in the plurality of metal case type cells.
In addition, the plurality of lithium ion cells 161 may include one or more metal case-type cells having a positive electrode, a negative electrode, and an electrolyte, and one or more metal case-type cells having a positive electrode, a negative electrode, and a solid electrolyte. . In this case, the electrolyte solutions included in at least two metal case-type cells among the plurality of metal case-type cells having the positive electrode, the negative electrode, and the electrolyte solution may be the same type or different from each other. Moreover, the solid electrolyte which at least 2 metal case type cell has among the some metal case type cells which have a positive electrode, a negative electrode, and a solid electrolyte may be mutually the same kind, and may mutually differ.

<Temperature adjustment apparatus> In the specific example of the said embodiment, the temperature adjustment apparatus may be accommodated in the housing part. The temperature adjusting device adjusts the temperature of a space formed between adjacent lithium ion cells. The temperature adjusting device may be an air cooling fan, for example. The temperature adjusting device may be, for example, cold water or hot water. The temperature adjusting device may be a heater, for example.

Example of Modification of Device on which Assembly Battery is Mounted The assembly battery 16 of a specific example of the above embodiment is mounted on a saddle riding type vehicle 1 having an engine. However, the assembled battery of the present invention may be mounted on a straddle-type vehicle using a motor as a drive source, or may be mounted on a straddle-type vehicle using a motor and an engine as drive sources. The assembled battery of the present invention may be mounted on a power consuming device other than the saddle riding type vehicle. The electric power stored in the assembled battery is used to drive the power consuming device. The type of power consuming device on which the assembled battery is mounted is not particularly limited. The power consuming device may be a vehicle or may not be a vehicle. The vehicle may use an engine as a driving source, may use a motor as a driving source, or may use an engine and a motor as driving sources. When the assembled battery of the present invention is mounted on a vehicle including a motor as a drive source, the assembled battery supplies power to the motor (drive source). The vehicle may travel on land, may travel on water, travel in water, or travel in the air. Vehicles that travel on land are, for example, four-wheel vehicles, two-wheel vehicles, three-wheelers, snowmobiles, and the like. A vehicle traveling on land may have more than four wheels. The four-wheeled vehicle is, for example, a passenger car, an ATV (All Terrain Vehicle), a ROV (Recreational Off-highway Vehicle), a golf cart, a forklift, or the like. The two-wheeled vehicle may have two wheels lined up in the front-rear direction, or may have two wheels lined up in the left-right direction. Examples of the former include motorcycles (motorcycles), scooters, mopeds, bicycles, and the like. The tricycle may have two front wheels or two rear wheels. Vehicles that travel on the water are, for example, ships, water bikes, and the like. The vehicle that travels underwater is, for example, a submersible craft. Vehicles that travel in the air are, for example, airplanes, helicopters, drones, and the like.

The assembled battery of the present invention may be detachable from the power consuming device, or may not be detachable. The assembled battery may be charged while being removed from the power consuming device, or may be charged while being mounted on the power consuming device.

Modification Example Related to Charging of Battery Assembly The battery assembly of the present invention may be chargeable with a charger other than a DC charger for 12V to 15V. When the assembled battery can be charged with a DC charger having a voltage higher than 12V to 15V, the assembled battery can be used in place of a lead storage battery mounted on a vehicle using a motor as a drive source.

Hereinafter, characteristics of an example of a metal case type cell (hereinafter sometimes referred to as a lithium ion cell according to an example of the present invention) included in the assembled battery of the present invention will be described with reference to FIGS. The lithium ion cell according to the present invention is a so-called 18650 cell, which is a cylindrical lithium ion cell having a diameter of 18 mm and a length of 65.0 mm.

(1) Discharge characteristics at different current values The lithium ion cell according to the example of the present invention was charged by a constant current constant voltage method. The charging current in constant current charging was 1A. The charging voltage in constant voltage charging was 4.2V. The charge termination current was 0.05A. After the completion of charging, the lithium ion cell according to the example of the present invention was discharged at a constant current. Each discharge capacity when the discharge current in constant current discharge was set to 1A, 3A, 5A, and 10A was investigated. The final discharge voltage was 2.5V. The discharge current is also called output current.

FIG. 8 shows the discharge characteristics of the lithium ion cell when the discharge current is 1A, 3A, 5A, and 10A. The vertical axis in FIG. 8 indicates the voltage of the lithium ion cell, and the horizontal axis in FIG. 8 indicates the discharge capacity of the lithium ion cell. From FIG. 8, the discharge capacity exceeds 1 Ah when the discharge current is 1A, 3A, 5A, and 10A. From this, it was found that the lithium ion cell according to the example of the present invention can be used even at a high discharge rate.

(2) Cycle characteristics under different temperature environments The cycle characteristics of lithium ion cells under the following three temperature environments were examined. Under a temperature environment of 60 ° C., charging and discharging of the lithium ion cell according to the example of the present invention were repeated. In a temperature environment of −10 ° C., charging and discharging of the lithium ion cell according to the example of the present invention were repeated. Under the temperature environment assuming the four seasons of ASEAN, charging and discharging of the lithium ion cell according to the example of the present invention were repeated. Specifically, it was assumed that the temperature for one year changes in the order of 40 ° C., 25 ° C., 10 ° C., and 25 ° C. Charging and discharging were counted as one cycle, and the environmental temperature was repeatedly changed in order of 40 ° C., 25 ° C., 10 ° C., and 25 ° C. every 2500 cycles.

First, in order to fully charge the lithium ion cell, the lithium ion cell was charged by a constant current constant voltage method. The charging current in constant current charging was 1A. The charging voltage in constant voltage charging was 3.65V. The charge termination current was 0.05A. Thereafter, charging and discharging were repeated. Each time 2500 cycles were completed, the lithium ion cell was fully charged. When the lithium ion cell was fully charged, the lithium ion cell was charged with a constant current and constant voltage method. The charging current in constant current charging was 1A. The charging voltage in constant voltage charging was 3.65V. The charge termination current was 0.05A.

FIG. 9 shows a load current pattern of one cycle in the charge / discharge cycle. The vertical axis in FIG. 9 is the load current, and the horizontal axis in FIG. 9 is the time. In FIG. 9, when the load current is negative, the lithium ion cell is discharged. In FIG. 9, when the load current is positive, the lithium ion cell is charged. The load current pattern shown in FIG. 9 was generated based on the running conditions defined in ECE40 (ISO 6460). The traveling condition defined in ECE40 (ISO 6460) may be referred to as an ECE40 traveling pattern. The ECE40 running pattern is a running pattern in the ECE40 urban cycle mode that is a European practical fuel consumption measurement method.

The battery capacity of the lithium ion cell was measured every 2500 cycles. Specifically, the following method was used. First, the battery was charged by a constant current constant voltage method in a temperature environment of 25 ° C. The charging current in constant current charging was 1A. The charging voltage in constant voltage charging was 3.65V. The charge termination current was 0.05A. After completion of charging, constant current discharge was performed in a temperature environment of 25 ° C., and the discharge capacity of the lithium ion cell was measured. The discharge current in constant current discharge was 1A. The final discharge voltage was 2.5V.

By dividing the discharge capacity of the lithium ion cell at every 2500 cycles by the discharge capacity at the time of discharge in the first cycle, the discharge capacity at the time of discharge in the predetermined cycle relative to the discharge capacity at the time of discharge in the first cycle was obtained. . Here, the discharge capacity at the time of discharge in the predetermined cycle to the discharge capacity at the time of discharge in the first cycle is referred to as an initial capacity ratio. This initial capacity ratio may be referred to as a capacity maintenance ratio.

FIG. 10 shows the relationship between the initial capacity ratio and the number of cycles. The vertical axis in FIG. 10 is the initial capacity ratio, and the horizontal axis in FIG. 10 is the number of cycles. FIG. 10 shows the following. In a low temperature environment of −10 ° C. and a temperature environment assuming the four seasons of ASEAN, the initial capacity ratio at the 20000th cycle was 95%. Moreover, the initial capacity ratio in the low temperature environment of −10 ° C. and the initial capacity ratio in the temperature environment assuming the four seasons of ASEAN show similar trends. From this, it was found that the lithium ion cell according to the example of the present invention has the same durability as the temperature environment assuming the four seasons of ASEAN even when charging and discharging are repeated in a low temperature environment of −10 ° C. Further, the initial capacity ratio at the 20000th cycle was 80% even in a high temperature environment of 60 ° C. From this, it can be said that the lithium ion cell according to the example of the present invention has high durability even in a high temperature environment. From the above, the lithium ion cell according to the example of the present invention has high durability in both a low temperature environment and a high temperature environment. That is, the lithium ion cell according to the example of the present invention is hardly deteriorated even in a low temperature environment or a high temperature environment. Therefore, the lithium ion cell which concerns on the example of this invention has a high freedom degree of use environment.

(3) Comparison of cycle characteristics of inventive example and comparative example As a comparative example, a lithium ion cell in which the positive electrode active material was lithium iron phosphate and the negative electrode active material was graphite was used.
In an environment of 45 ° C., charging and discharging of the lithium ion cell according to the example of the present invention and the lithium ion cell of the comparative example were repeated. Specifically, the constant current discharge was repeated after the constant current and constant voltage charge. The standby time from the end of charging to the start of discharging was 30 minutes. The standby time from the end of discharging to the start of charging was 30 minutes. The charging current in constant current charging was 3A. The charging voltage in constant voltage charging was 3.6V. The charge termination current was 0.05A. The discharge current for constant current discharge was 3A. The final discharge voltage was 2.5V.

When charging and discharging of a predetermined cycle were completed, the discharge capacity of the lithium ion cell was measured by the following method.

First, the battery was charged by a constant current constant voltage method in an environment of 25 ° C. The charging current in constant current charging was 1A. The charging voltage in constant voltage charging was 3.65V. The charge termination current was 0.05A. Thereafter, constant current discharge was performed in an environment of 25 ° C., and the discharge capacity of the lithium ion cell was measured. The discharge current was 1A. The final discharge voltage was 2.5V.

The discharge capacity at the first cycle discharge and the discharge capacity at the end of the predetermined cycle were measured. By dividing the discharge capacity at the end of the predetermined cycle by the discharge capacity at the end of the first cycle, the discharge capacity at the end of the predetermined cycle relative to the discharge capacity at the end of the first cycle is obtained. Asked. Here, the discharge capacity at the time of discharge after completion of a predetermined cycle with respect to the discharge capacity at the time of discharge in the first cycle is referred to as an initial capacity ratio.

FIG. 11 shows the relationship between the initial capacity ratio and the number of cycles. The vertical axis in FIG. 11 is the initial capacity ratio, and the horizontal axis in FIG. 11 is the number of cycles. From FIG. 11, in each cycle, the initial capacity ratio of the lithium ion cell according to the example of the present invention was larger than the initial capacity ratio of the lithium ion cell of the comparative example. The initial capacity ratio of the lithium ion cell according to the example of the present invention was about 99% in 100 cycles. On the other hand, the initial capacity ratio of the lithium ion cell according to the comparative example was lower than about 96% in 100 cycles.
It was found that the deterioration of the lithium ion cell according to the example of the present invention was suppressed as compared with the lithium ion cell of the comparative example.

From the above, the lithium ion cell according to the example of the present invention is suppressed from being deteriorated even when it is repeatedly charged and discharged in a low temperature environment and a high temperature environment. Moreover, the lithium ion cell which concerns on the example of this invention has suppressed degradation, even if it repeats charge and discharge over a long period of time. Therefore, the assembled battery having a plurality of lithium ion cells according to the present invention can suppress deterioration of the lithium ion cell even in an environment where the assembled battery mounted on the saddle riding type vehicle is used.

The assembled battery of Japanese Patent Application No. 2017-038284, which is the basic application of the present application, is included in the assembled battery of the present specification. The lithium ion battery 161 in the basic application corresponds to the metal case type cell 161 or the lithium ion cell 161 of the present specification. The can 1613 in the basic application corresponds to the metal case 1613 or the metal case 1613 of the present specification. The case portion 162 in the basic application corresponds to the housing portion 162 in the present specification. The can battery fixing part 163 in the basic application corresponds to the metal case type cell fixing part 163 of the present specification.

1 Saddle-type vehicle 2 Engine (drive source)
3 starter motor 16 assembled battery 161 metal case type cell (lithium ion cell)
1611 Positive electrode 16111 Positive electrode active material 1612 Negative electrode 16121 Negative electrode active material 16121a Carbon layer 16121b Carbon layer 16121c Carbon layer 1613 Metal case (metal case)
1615 Electrolytic solution 162 Housing portion 162a Upper surface 162b Lower surface 162a Upper surface 162b Lower surface 162c Side surface 162d Side surface 162e Side surface 162f Side surface 163 Metal case type cell fixing plate 1631 Metal case type cell fixing plate 164 Connection portion 1641 Connection plate 1642 Connection plate 1643 Connection plate 1644 Connection plate 1645 Connection plate 171 Parallel cell group 1711 Parallel cell group 1712 Parallel cell group 1713 Parallel cell group 1714 Parallel cell group 172 Series cell group

Claims (10)

1. A battery pack having a plurality of lithium ion cells electrically connected to each other,
   Each of the plurality of lithium ion cells is
   One positive electrode,
   One negative electrode,
   An electrolyte or solid electrolyte;
   A metal case type cell having the one positive electrode, the one negative electrode, and a metal can case containing the electrolytic solution or solid electrolyte;
   Each of the plurality of metal case type cells is connected in series to any of the plurality of metal case type cells,
   The positive electrode has an olivine-structured positive electrode active material,
   The negative electrode is a negative electrode active material including a plurality of carbon layers stacked, and has a negative electrode active material in which an average interlayer distance of the plurality of carbon layers is not less than a diameter of lithium atoms,
   The assembled battery is
   An assembled battery having a metal case type cell fixing portion for fixing the plurality of metal case type cells to each other.
2. The assembled battery according to claim 1,
   In at least one metal case type cell of the plurality of metal case type cells,
   The one positive electrode, the one negative electrode, and the electrolyte are accommodated in the metal case type cell,
   An assembled battery, wherein the electrolytic solution is an electrolytic solution that does not freeze at −20 ° C.
3. The assembled battery according to claim 1 or 2,
   An assembled battery having a case portion housing portion that accommodates both the plurality of metal case type cells and the metal case type cell fixing portion.
4. The assembled battery according to claim 3,
   1 provided in the housing part in a state accessible from the outside of the housing part and electrically connected to at least one of the positive electrodes of at least one metal case type cell of the plurality of metal case type cells. Two external positive terminals,
   1 provided in the housing part in a state accessible from the outside of the housing part and electrically connected to at least one negative electrode of at least one metal case type cell of the plurality of metal case type cells. An assembled battery having two external negative terminals.
5. The assembled battery according to claim 4,
   The housing part is a box having a plurality of surfaces respectively arranged along a plurality of planes intersecting each other.
   The one external positive terminal and the one external negative terminal are both provided on one of the plurality of surfaces.
6. The assembled battery according to any one of claims 1 to 5,
   The plurality of metal case type cells are connected in series in one row,
   The metal case type cell fixing part is:
   An assembled battery that fixes the plurality of metal case-type cells in a state of being connected in series in a row.
7. The assembled battery according to any one of claims 1 to 5,
   The plurality of metal case-type cells comprise a plurality of series cell groups consisting of at least two metal case-type cells connected in series with each other,
   The plurality of series cell groups are connected in parallel to each other,
   The metal case type cell fixing part is:
   An assembled battery that fixes a plurality of series cell groups connected in parallel.
8. The assembled battery according to any one of claims 1 to 5,
   The plurality of metal case cells comprise a plurality of parallel cell groups composed of at least two metal case cells connected in parallel to each other,
   The plurality of parallel cell groups are connected in series with each other,
   The metal case-type cell fixing part is an assembled battery that fixes a plurality of parallel cell groups connected in series.
9. The assembled battery according to any one of claims 1 to 8,
   An assembled battery that can be charged with a DC charger for 12V to 15V.
10. The assembled battery according to any one of claims 1 to 9,
    At least one front wheel;
    At least one rear wheel;
    An assembled battery that can be mounted on a straddle-type vehicle including at least a part of the vehicle in the front-rear direction and a drive source disposed behind the at least one front wheel.

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