JP2002319388A - Batteries, assembled batteries and terminals - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery whose temperature rise is suppressed, an assembled battery constituted by using this battery, and a terminal which is used as a component of the battery and which can enhance the heat dissipation of the battery. To do. SOLUTION: A lithium ion secondary battery 1 to which the present invention is applied includes an electrode body 10 provided with a positive electrode sheet 13 and a negative electrode sheet 18, a container 40 for accommodating the electrode body 10, and connected to the electrode body 10 and outside the container. And protruding terminals 20 and 30. The terminals 20 and 30 are current collecting terminals 21 and 31 connected to the positive electrode sheet 13 and the negative electrode sheet 18, respectively.
And external terminals 22 and 32 connected to the current collecting terminals 21 and 31 and protruding outside the container. These external terminals 22, 32
Is provided with a heat dissipating fin structure by forming two grooves extending in the circumferential direction on its outer periphery. The assembled battery of the present invention is configured by electrically connecting a plurality of the batteries 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery and an assembled battery in which a plurality of the batteries are electrically connected, and more particularly, to a battery and an assembled battery capable of efficiently suppressing a rise in battery temperature. Furthermore, the present invention relates to terminals used for these batteries and assembled batteries.

[0002]

2. Description of the Related Art A battery (a lithium ion battery, a nickel hydrogen battery, or the like) in which an electrode body having a positive electrode and a negative electrode is housed in a container is known. FIG. 10 shows an example of the structure of such a conventional battery. The electrode body 110 accommodated in the container 140 includes a positive electrode sheet (positive electrode) 113 in which a positive electrode current collector holds a positive electrode active material, and a negative electrode sheet (negative electrode) 118 in which a negative electrode current collector holds a negative electrode active material. Is provided. The two sheets 113 and 118 are overlapped via a separator (not shown), and are wound to form the electrode body 110. At both ends of the electrode body 110, the positive electrode sheet 113
The positive electrode terminal 120 and the negative electrode terminal 130 are connected to the negative electrode sheet 118 by welding or the like, respectively. End portions 122 of these positive electrode terminal 120 and negative electrode terminal 130
a and 132a protrude outside the container 140. The electrode body 110 is impregnated with an electrolytic solution (not shown) that mediates a battery reaction.

[0003]

However, batteries generate heat as they are charged and discharged. In particular, when rapid charge / discharge or internal short-circuit occurs, a large amount of heat is generated in a short time. In a battery in which the electrode body is housed in a container as shown in FIG. 10, the temperature of the battery tends to rise because heat is easily stored in the container. In order to suppress the rise in the battery temperature, a battery provided with a radiation fin outside the container has been proposed. However, since an insulating film, an electrolytic solution, and the like are interposed between the electrode body and the container, the heat transfer between them cannot be said to be high. Therefore, in such a configuration in which heat is radiated through the container, the cooling efficiency of the electrode body is low. Also,
Regarding a battery using a wound type electrode body, a battery has been proposed in which the winding core is extended to the outside of the container and a radiation fin is attached. However, in the battery having such a configuration, the provision of the heat radiation fins increases the size and the weight of the battery.

[0004] Further, in an application such as a battery for an automobile, an assembled battery in which a plurality of batteries are electrically connected as shown in FIG. 10 is sometimes used. FIG. 11 shows an example of the structure of such a battery pack. The plurality of batteries 100 constituting the assembled battery 150 are connected to each other via a conductive member 151 attached to the terminals 120 and 130. The conductive member 151 is attached to each terminal by a fixing bolt 152. These batteries 100 are each battery 1
00 are arranged with a predetermined space S between them. The space S is for circulating cooling air between the batteries 100 to suppress a rise in battery temperature. However, the cooling space S has increased the physical size of the assembled battery as a whole. Japanese Patent Application Laid-Open No. 6-60914 discloses a battery cooling device in which a tubular member containing a magnetic fluid is externally fitted to a conductive member for battery connection. However, the use of such a cooling device complicates the structure of the assembled battery. In addition, the use of a magnetic fluid increases material costs.

An object of the present invention is to provide a battery capable of suppressing a rise in temperature with a simple configuration.
Another object of the present invention is to provide a battery that can suppress a rise in temperature without significantly increasing the physical size. Another object of the present invention is to provide an assembled battery configured using the battery in which the temperature rise is suppressed as described above. Still another object of the present invention is to provide a terminal that can be used as a component of a battery and can enhance the heat dissipation of the battery.

[0006]

Means for Solving the Problems, Functions and Effects The battery of the present invention includes an electrode body, a container for housing the electrode body, and a terminal connected to the electrode body and protruding outside the container. A fin structure is provided on a portion of the terminal protruding outside the container. In this battery, a terminal used for conduction between the electrode body and the outside (such as an external circuit or another battery) is provided with a fin structure for heat dissipation. As described above, since the conduction terminals are also used for heat dissipation, heat dissipation can be improved without significantly complicating the structure of the battery. Usually, this terminal is made of a highly conductive material such as aluminum or copper. And since these terminal materials, such as aluminum and copper, also have high thermal conductivity, the heat of the electrode body can be efficiently dissipated outside through these terminals.
The fin structure may be provided on only one of the positive terminal and the negative terminal. Even in the battery having such a configuration, an effect of suppressing a rise in battery temperature can be obtained. A battery provided with a fin structure on both the positive electrode side terminal and the negative electrode side terminal is preferable because it has a high effect of suppressing a rise in battery temperature.

[0007] The battery pack of the present invention is formed by electrically connecting a plurality of the batteries of the present invention. This connection is performed by, for example, a conductive member (a plate-shaped member made of a conductive material,
(A bar-shaped member, a lead wire, or the like). Since this battery pack is composed of the battery of the present invention, the heat dissipation of each battery is good. Therefore, the cooling space provided between the batteries in the conventional battery pack is reduced, or the battery is not provided with this space (that is, the batteries are closely arranged). Heat dissipation can be obtained. As a result, the physique of the entire battery pack can be reduced.

[0008] The terminal of the present invention is used for connection to an electrode body of a battery, and is characterized in that a fin structure is provided at a portion protruding outside the battery container. Since the battery has the fin structure for heat dissipation, a battery having good heat dissipation properties can be formed using the terminal of the present invention. That is, the heat of the electrode body to which this terminal is connected can be efficiently dissipated outside the battery.

[0009]

Embodiments of the present invention are characterized in that they are implemented in the following modes. (Mode 1) In the terminal constituting the battery of the present invention or the terminal of the present invention, a fin structure is realized by providing a groove on the surface of the terminal. This groove can be formed, for example, by removing a part of the terminal surface that protrudes outside by cutting or the like. In this way, instead of attaching a fin member separate from the terminal to this terminal, a fin structure is formed by depressing the surface of the terminal (by the terminal itself) without increasing the size of the battery. The heat dissipation of the battery can be improved. Further, since the material constituting the terminal is reduced by the volume corresponding to the groove, the weight of the terminal can be reduced, and the weight of the battery can be reduced.

(Embodiment 2) In the terminal constituting the battery of the present invention or the terminal of the present invention, a fin structure is realized by providing an annular or spiral groove in the outer diameter of the terminal. The groove having such a shape can be easily formed by cutting or polishing the surface of the terminal. Further, it is hard to hinder the flow of air in the vicinity of the terminal or promotes the flow, so that the terminal is easily cooled by air. Therefore, the effect of releasing heat from the electrode body to the outside is high.

(Embodiment 3) The battery of the present invention is a non-aqueous electrolyte secondary battery. Alternatively, the terminal of the present invention is used for a non-aqueous electrolyte secondary battery. In general, non-aqueous electrolyte secondary batteries are not restricted by the decomposition potential of water,
Higher voltage is possible as compared to a battery using an aqueous electrolyte. In such a secondary battery capable of generating a high voltage, the need to suppress the temperature rise of the battery increases. Therefore, the effect of improving heat dissipation by applying the present invention is remarkably exhibited. Note that a typical example of the nonaqueous electrolyte secondary battery is a lithium ion secondary battery.

(Mode 4) The terminals constituting the battery of the present invention are directly connected (directly connected) to the electrode body of the battery. By directly connecting the electrode body and the terminal in this way, it is possible to increase the thermal conductivity between the electrode body and the terminal as compared with a case where these are electrically connected via, for example, a current collecting lead. it can. As a result, the battery having such a configuration has particularly good heat dissipation. This electrode body may be of any type such as a wound type, a laminated type and a folded type. For example, each of the positive electrode sheet and the negative electrode sheet constituting these electrode bodies may be provided with a portion that does not hold an active material (active material uncoated portion), and a terminal may be connected to this portion by, for example, welding. it can.

(Embodiment 5) In the battery pack of the present invention, the batteries constituting the battery pack are closely arranged. That is, there is substantially no cooling space between these batteries. With such a configuration,
The size of the assembled battery can be reduced. As a result, the mountability on a vehicle or the like is improved.

[0014]

(First Embodiment) FIG. 1A is a sectional view showing the whole structure of a battery according to a first embodiment, and FIG. 1B is a right side view thereof (FIG. 1B). ) Does not show the container wall on the near side.) The lithium ion secondary battery 1 includes a wound electrode body 10 including a positive electrode sheet (positive electrode) 13 and a negative electrode sheet (negative electrode) 18, a container 40 for accommodating the electrode body 10, and an axial direction of the electrode body 10. A positive terminal 20 and a negative terminal 30 are connected to both ends, respectively. The positive electrode terminal 20 includes a positive electrode current collecting terminal 21 having one end connected to the positive electrode sheet 13, and a positive electrode external terminal 22 connected to the other end of the positive electrode current collecting terminal 21 and penetrating through the container 40 and protruding outside. Is done. Similarly, for the negative electrode terminal 30, the negative electrode sheet 1
8, a negative current collecting terminal 31 and a negative current collecting terminal 31
And a negative electrode external terminal 32 penetrating the container 40 and protruding to the outside thereof. Portions of the positive electrode external terminal 22 and the negative electrode external terminal 32 protruding outside the container 40
Is provided with a heat dissipating fin structure by forming two grooves extending in the circumferential direction on its outer periphery. Hereinafter, the lithium ion secondary battery 1 will be described in more detail.

First, the configuration and manufacturing method of the electrode body 10 will be described. FIG. 2 shows a positive electrode sheet 1 constituting the electrode body 10.
3 shows a state before winding. As the positive electrode current collector 11, a long aluminum foil having a thickness of 25 μm was used. A paste containing the positive electrode active material was prepared, and the positive electrode active material paste was applied to both surfaces of the positive electrode current collector 11. After the applied paste is dried, the paste is pressed so that the entire thickness becomes 85 μm, and the positive electrode active material layer 12 is formed on both surfaces of the positive electrode current collector 11.
Was formed. Thus, the positive electrode sheet 13 was produced. Here, on one long side of the positive electrode sheet 13, an active material uncoated portion 13a in which the positive electrode active material layer 15 is not formed on any surface is provided.

Since the structure of the negative electrode sheet 18 is the same as that of the positive electrode sheet 13, the negative electrode sheet 18 will be described with reference to FIG. In FIG. 2, reference numerals in parentheses correspond to the negative electrode sheet 18. Negative electrode current collector 16
Was used as a long copper foil having a thickness of 30 μm. A negative electrode active material paste was applied to both surfaces of the negative electrode current collector 16. After drying the applied paste, the total thickness is 80μ
m, to obtain a negative electrode sheet 18 in which a negative electrode active material layer 17 was formed on both surfaces of a negative electrode current collector 16. On one long side of the negative electrode sheet 18, an active material uncoated portion 18 a in which the negative electrode active material layer 17 is not formed on any surface is provided.

As the separator, a porous polypropylene resin sheet having a thickness of 25 μm was used. The planar shape of this separator is substantially the same as the positive electrode active material layer 12 and the negative electrode active material layer 17 shown in FIG. The two sheets and the two sheets of the separator are stacked in the order of the separator, the positive electrode sheet 13, the separator, and the negative electrode sheet 18. At this time,
Active material uncoated portion 13a of positive electrode sheet 13 and negative electrode sheet 1
The two sheets are arranged so that the active material uncoated portion 18a of 8 protrudes from one long side and the other long side of the separator. Next, as shown in FIG. 3, both the superposed sheets and the separator are wound in the long-side direction using a winding machine or the like, and are pressed to form a wound body having an oval cross section. Further, a part of the active material uncoated portions 13a and 18a is compressed at both ends of the wound body. Specifically, FIG.
As shown in (1), at both ends of the roll pressed into an oval cross section, a range from one end of the oval to almost the center is further pressed. Thereby, portions where the positive electrode current collector 11 and the negative electrode current collector 16 are respectively brought to both ends of the wound body are formed. Thus, the electrode body 10 is manufactured.

The cathode active material used for manufacturing the electrode body 10 is LiMn ₂ O ₄ , LiCoO ₂ , LiNi
One or more of the positive electrode active materials used in conventional lithium ion secondary batteries, such as O ₃ , can be used without particular limitation. As the negative electrode active material, one or two or more types of negative electrode active materials used for a conventional lithium ion secondary battery, such as amorphous carbon and graphite carbon, can be used without particular limitation. In preparing a paste containing such an active material, conventionally known binders, conductive agents, solvents, and the like can be appropriately used. The application of these pastes to the current collector can be performed using a comma coater, a die coater, or the like.

Next, the structure of the positive electrode terminal 20 will be described. 4 to 6 show the shape of the positive electrode current collecting terminal 21 constituting the positive electrode terminal 20. FIG. This positive current collector terminal is 1.5mm thick
The aluminum plate is press-formed, and its shape is determined so that the outer shape falls within a range of 15 mm in width × 8 mm in depth × 50 mm in height. At the lower end of the positive electrode current collecting terminal 21, a welded portion 21a which is a portion to be welded to the electrode body 10 is provided.
Are formed. As shown in FIG.
Through hole 21b for welding positive external terminal 22 shown in FIG.
Are formed. This positive electrode external terminal 22 is made of aluminum. As shown in FIGS. 1 and 7, the protruding portion (portion protruding outside the container 40) 22a of the positive electrode external terminal 22 has a columnar outer shape with a diameter of 14 mm and a height of 15 mm. The side of this cylinder is 1mm wide x 1mm deep by cutting or the like.
The two annular grooves 22b are formed. These annular grooves 22b provide a fin structure to the protruding portion 22a of the positive electrode external terminal 22. From the lower part of the protruding part 22a, a connecting part 22c for welding with the positive electrode current collecting terminal 21 is formed.
Extends like a bar. Further, a tap 22d opening at the upper end of the positive electrode external terminal 22 is formed inside the protruding portion 22a. The tap 22d has a size for an M6 bolt. Note that the negative electrode terminal 30 is configured in the same manner as the positive electrode terminal 20 except that copper is used instead of aluminum as a material, and thus description thereof is omitted. 4 to 7, the reference numerals in parentheses correspond to the negative terminal 30.

The outer shape of the container 40 is 120 mm wide × 20 mm deep.
× A rectangular parallelepiped with a height of 90 mm. The container 40 includes a bottomed rectangular cylindrical battery case 41 made of an aluminum plate having a thickness of 1 mm, and a lid 42 made of an aluminum plate having a thickness of 2 mm and attached to an upper surface of the battery case 41.

Hereinafter, an example of a method for manufacturing the battery 1 using these members will be described. The connection portion 22c of the positive external terminal 22 and the connection portion 32c of the negative external terminal 32 shown in FIG. 7 are respectively passed through two through holes (not shown) provided in the lid 42 shown in FIG. Here, a resin packing (not shown) is arranged between the lid 42 and the external terminals 22 and 32 to insulate them from each other and to ensure the sealing property inside the container 40. The lower ends of the connecting portions 22c and 32c are further connected to the through holes 2 provided in the current collecting terminals 21 and 31.
1b, 31b, and the external terminals 22, 32 and the current collecting terminals 21, 31 are fixed by welding (see FIGS. 4 to 7). Then, the welded portions 21a, 31a of the current collecting terminals 21, 31 are connected to both ends of the electrode body 10 shown in FIG.
8a is pressed into the uncompressed portion) to form a weld 21
a, 31a and the active material uncoated portions 13a, 18a are fixed by ultrasonic welding or the like. Thereby, the lid 42, the external terminals 22, 32, the current collecting terminals 21, 31, and the electrode body 10 are integrated.

The electrode body 10 is impregnated with an electrolytic solution (not shown) using, for example, a vacuum type liquid injection device. As the electrolytic solution, a solution obtained by dissolving 1 mol / liter of LiPF ₆ in a 7: 3 (weight ratio) mixed solvent of diethyl carbonate and ethylene carbonate was used. Then, as shown in FIG. 1, the lid 42, the external terminals 22, 32, the current collecting terminal 2
The battery unit 41 in which the electrodes 1, 31 and the electrode body 10 are integrated is housed in a battery case 41, and the battery case 41 and the lid 42 are welded to seal the container 40. Thus, the lithium ion secondary battery 1 is manufactured.

In the lithium ion secondary battery 1 having such a configuration, the heat generated at the time of charge / discharge or the like in the electrode body 10 is transferred to the current collectors 11 and 16 constituting the electrode body 10 directly. The heat can be radiated to the outside of the container 40 through the electrical terminals 21 and 31 and the external terminals 22 and 32 directly connected to these terminals. This heat release suppresses a temperature rise of the lithium ion secondary battery 1. Since the current collectors 11 and 16, the current collecting terminals 21 and 31, and the external terminals 22 and 32 are all made of a material having good thermal conductivity (aluminum or copper), the heat of the electrode body 10 is transferred to the tips of the external terminals 22 and 32. (Protrusions 22a, 32a) can be efficiently transmitted. And since the fin structure is provided at the tip of these external terminals 22 and 32, heat dissipation is good. This fin structure is formed by processing (providing a groove) the external terminals 22 and 32 themselves. Therefore, the provision of the fin structure does not increase the number of components of the battery. Since the fin structure is formed by removing a part of the material constituting the external terminals 22 and 32 by cutting or the like, the physique of the external terminals 22 and 32 does not increase due to the formation of the fin structure. Weight is reduced by the formation of grooves.

(Second Embodiment) FIG. 8 shows the overall structure of a battery pack according to a second embodiment. In the battery pack 50, a plurality of lithium ion secondary batteries 1 of the first embodiment are arranged in parallel without providing a space between the batteries 1. Adjacent batteries 1 are electrically connected by a conductive member 51. The conductive member 51 is made of a copper plate having a thickness of 1.5 mm and a width of 8 mm, and is provided with taps 22 provided on the external terminals 22 and 32.
The fixing bolts 52 are attached to the battery 1 by screwing the fixing bolts 52 to d and 32d (see FIG. 7). As the fixing bolt 52, an M6 bolt was used. The entirety is housed in a metal or resin case (not shown).

A current of 30 A was supplied to the battery pack 50 having the above-mentioned structure while sending a predetermined amount of cooling air. In this state, the container 4 when the internal temperature of the battery becomes substantially constant
The temperature within 0 (equilibrium temperature) was measured. As a control, as shown in FIG. 11, a lithium ion secondary battery 100 having the same configuration as that of the embodiment except that an external terminal having no annular groove was used. An assembled battery having a cooling space S of 2 to 3 mm was prepared. Using this control battery pack, the equilibrium temperature when a predetermined amount of cooling air was sent was measured as in the battery pack of the second embodiment. Fig. 9 shows the relationship between the volume of cooling air and the equilibrium temperature.
Shown in In FIG. 9, the interval between the characteristic curve corresponding to the battery pack of the second embodiment and the characteristic curve corresponding to the control battery pack is about 0.2 to 0.5 ° C.

As can be seen from FIG. 9, the assembled battery of the second embodiment has substantially the same cooling performance (a rise in temperature inside the battery) as that of the control assembled battery in which a cooling space is provided between each battery. Performance). That is, according to the battery pack of the present invention, the provision of the fin structure on the terminal allows the cooling space around each battery to be two to two even though no cooling space is provided between the batteries. The same cooling effect as in the case of opening every 3 mm was obtained. That is, according to the battery pack of the present invention, the physical size of the battery pack can be reduced as compared with the related art while maintaining the predetermined cooling performance. As a result, the mountability on a vehicle or the like is improved.

In the above embodiment, a lithium ion secondary battery and an assembled battery constituted by using the lithium ion secondary battery have been described. However, the present invention is not limited to nickel hydrogen batteries, nickel cadmium batteries, and other types of batteries. The present invention can also be applied to batteries and batteries assembled from these batteries. The materials of the active materials of the positive electrode and the negative electrode, the current collector and the terminal, the separator and the like, the composition of the electrolytic solution, and the like are appropriately selected according to the type of the battery. Furthermore, the present invention can be applied to a capacitor to efficiently suppress a temperature rise. That is, in the present invention, the battery is a concept including a “capacitor”. Specific examples of the capacitor to which the present invention is applied include an electric double layer capacitor having an electrode in which a layer containing activated carbon as an active material is formed on the surface of a current collector.

Further, in the above embodiment, the terminals used for both poles are composed of two members, that is, a current collecting terminal and an external terminal. However, one or both terminals may be composed of one member. You may comprise from more than one member. The shape of the terminal may be any shape as long as one end is connected to the electrode body and the other end is projected outside the container, and is not limited to the above embodiment. For example, in the above embodiment, the shape of the portion protruding to the outside of the container (external shape not including the groove) is cylindrical, but in addition, a polygonal prism (hexagonal prism, quadrangular prism, etc.),
The shape may be an elliptical column, a flat plate, or the like.

[Brief description of the drawings]

FIG. 1A is a sectional view showing a lithium ion secondary battery according to a first embodiment, and FIG. 1B is a side view thereof.

FIG. 2 is a plan view showing a positive electrode sheet constituting the lithium ion secondary battery according to the first embodiment.

FIG. 3 is a perspective view showing an electrode body constituting the lithium ion secondary battery according to the first embodiment.

FIG. 4 is a front view showing a current collecting terminal of the lithium ion secondary battery according to the first embodiment.

FIG. 5 is a view as seen in the direction of arrow V in FIG. 4;

FIG. 6 is a view taken in the direction of arrow VI in FIG. 4; .

FIG. 7 is a front view showing external terminals constituting the lithium ion secondary battery according to the first embodiment.

FIG. 8 is a front view showing an assembled battery according to a second embodiment.

FIG. 9 is a characteristic diagram showing heat dissipation of the battery pack and the control battery pack according to the second embodiment.

FIG. 10 is a sectional view showing a conventional battery.

FIG. 11 is a sectional view showing a conventional battery pack.

[Explanation of symbols]

 1: Lithium ion secondary battery 10: Electrode body 13: Positive electrode sheet 18: Negative electrode sheet 20: Positive electrode terminal (terminal) 21: Positive current collecting terminal 22: Positive external terminal 22a: Projecting portion 22b: Annular groove 30: Negative electrode terminal ( Terminal) 31: negative electrode current collecting terminal 32: negative electrode external terminal 40: container 50: assembled battery 51: conductive member

Claims (3)

[Claims] 1. A battery comprising an electrode body, a container for accommodating the electrode body, and a terminal connected to the electrode body and protruding outside the container, wherein a fin structure is provided on a portion of the terminal protruding outside the container. . 2. An assembled battery comprising a plurality of the batteries according to claim 1 electrically connected to each other. 3. A terminal connected to an electrode body of a battery and provided with a fin structure at a portion protruding outside a battery container.