JP2011238526A - Charge/discharge control method and charge/discharge controller of power storage device - Google Patents

Abstract

A charge / discharge control method and a charge / discharge control apparatus capable of maintaining a power storage device in an appropriate partial charge state by estimating the degree of deterioration and performing charge / discharge control.
When a state detection request signal is input to a state detection unit 103 (step S1), it is determined in step S3 whether a selection condition for state detection mode 1 is satisfied. If the selection condition of the state detection mode 1 is satisfied, the battery 11 is charged before state detection in step S4, and the state of the storage battery 11 is detected in step S5. On the other hand, if it is determined that the selection condition for the state detection mode 1 is not satisfied, the state detection for the state detection mode 2 is performed in step S9. In step S11, a charge / discharge control command value necessary to shift the storage battery 11 to a predetermined partial charge state is created based on the result of the state detection.
[Selection] Figure 1

Description

  The present invention relates to a charge / discharge control method and a charge / discharge control device for an electricity storage device such as a liquid lead-acid battery, and more particularly to a charge / discharge control method and charge / discharge for performing control necessary to maintain the electricity storage device in a predetermined partial charge state. The present invention relates to a control device.

  In a conventional gasoline vehicle, a liquid lead storage battery, which is an electricity storage device, is used for an SLI battery, such as vehicle start, lighting, and ignition. When the storage battery is used for such an application, an operation is performed so that the state of charge is as fully charged as possible (SOC = 100%). In addition, power storage devices that are used as backup power sources such as servers during power outages are always operated in a fully charged state except during power outages. As described above, since it has been conventionally required that the power storage device has sufficient discharge capability when necessary, it is normally operated in a fully charged state and is controlled to a charged state other than a fully charged state. No charge / discharge control was required.

  On the other hand, in recent years, from the viewpoint of energy saving and CO2 emission reduction, demands such as power generation by natural energy and idling stop of gasoline cars are increasing. Accordingly, an operation method different from the conventional one is also demanded for power storage devices. As an example, power storage devices used for wind power generation control the amount of power in order to suppress frequency fluctuations in the generated power accompanying fluctuations in the rotational speed of the windmill, in addition to applications that supply power when there is no wind, where sufficient power generation is not possible. Also used for Both applications are important in connecting wind power generation to an electric power system and performing stable power supply, and it is required to always maintain an electric storage device in a state where it can be charged and discharged.

  In addition, power storage devices installed in power supply systems that use solar cells are subject to weather and user requirements, such as charging / discharging according to the time of day and weather, charging using nighttime power, and power supply during power outages. Therefore, it is necessary to always maintain a state where charging and discharging are possible. Alternatively, the power storage system is required to have a function of predicting how much late-night power should be charged according to the weather of the next day and performing night-time charging.

  Furthermore, in a storage battery used in a gasoline vehicle having an idling stop function, it is necessary to secure power necessary for restart after stopping at an intersection while maintaining power supply to various loads of the vehicle. For this reason, it is necessary to control the power load that is less important as necessary, or in some cases, to stop the idling stop and restart the charging of the storage battery with the generator (alternator).

  In order to realize the demand for the electricity storage device as described above, it is necessary that the electricity storage device is maintained not only in a dischargeable state but also in a state where it can be charged as necessary. That is, as a new operation method different from the conventional one for an electricity storage device, operation in a partially charged state (PSOC: Partial State of Charge) is required. A comparison between conventional operating conditions of the electricity storage device and operating conditions in the PSOC will be described with reference to FIG. FIG. 4A is an explanatory diagram showing conventional operating conditions of the electricity storage device, and FIG. 4B is an explanatory diagram showing operating conditions in the PSOC.

  In the conventional operating condition of the electricity storage device shown in FIG. 16 (a), a discharge range (SOC is 80 to 80%) from full charge (charge rate SOC is 100%) to at most about 10 to 20% of the total discharge capacity of the electricity storage device. The SOC is used in the operation region 11), and the SOC lower than that is used as a margin for deterioration of the power storage device (deterioration margin 12). The deterioration margin 12 is a dischargeable region. On the other hand, in the operation of the electricity storage device by PSOC shown in FIG. 16B, the SOC is used in a range of 20 to 80%, for example (referred to as the operation region 13), and the range of SOC from 80% to full charge is This is a chargeable range provided so that it can be charged when necessary (referred to as charging area 14). Further, the SOC range lower than the operation area 13 becomes the deterioration margin 15 and is a dischargeable area. By operating the electricity storage device with such a PSOC, charging and discharging can be performed when necessary.

  In order to appropriately perform the operation using the PSOC, it is important to be able to appropriately detect the charging capability, discharging capability, and deterioration of the electricity storage device. In the conventional operation, the power storage device is always kept fully charged, and it is important to detect the discharge capability. The discharge capability of the fully charged power storage device can be detected by subtracting the deterioration from the discharge capability when new. On the other hand, in the state detection of the electricity storage device when operating in PSOC, it is necessary to be able to detect both the charging ability and the discharging ability accompanying the deterioration of the electricity storage device.

  FIG. 17 shows a conceptual diagram of state detection required for the electricity storage device. FIG. 4A shows state detection in the conventional operation method, and FIG. 4B shows state detection in the PSOC operation method. In the state detection in the conventional operation method, as shown in FIG. 17A, it is required to detect the decrease 12a of the deterioration margin 12 due to deterioration and determine the remaining deterioration margin 12b. On the other hand, in the state detection in the PSOC operation method, as shown in FIG. 17B, the respective decrements 14a and 15a of the charging region 14 and the deterioration margin 15 due to deterioration are detected, and the necessary charging capacity and discharge are detected. In order to secure the capacity, it is necessary to perform control such as changing the operation area 13 to the area 13 ′ and newly providing the charging area 14b and the deterioration margin 15b. That is, in the operation of PSOC, it is necessary to accurately detect the chargeable capacity (COA), the dischargeable capacity (COD), and the degree of deterioration (SOH) of the power storage device.

  Regarding the state determination and charge control method of the electricity storage device operated by the PSOC as described above, there is a known technique as disclosed in Patent Document 1. In Patent Document 1, the voltage of the storage battery is measured before and after the end of charging or discharging, the apparent resistance value at the end of charging / discharging is calculated from this measured voltage, and this is compared with a reference value to deteriorate the storage battery. A method for estimating the degree is disclosed. Further, it is described that charge / discharge control is performed based on the estimated degree of deterioration so as to suppress the progress of deterioration.

  Another known technique for detecting the state of an electricity storage device is disclosed in Patent Document 2. Here, there is described a method for smoothing a charge capacity that detects a charge capacity of each cell and improves mutual imbalance in a storage battery composed of a plurality of cells.

JP 2008-192607 A Japanese translation of PCT publication No. 2008-520179

  However, the technique described in Patent Document 1 uses only the open circuit voltage (OCV) immediately after the end of charging / discharging, and does not mention any change with time of OCV. In Patent Document 1, only a deterioration mode related to a reaction having a very fast relaxation process is regarded as a deterioration parameter. For a storage battery having a time-consuming relaxation process such as diffusion of an electrolyte, the method described in Patent Document 1 is used. Therefore, the state detection cannot be performed with high accuracy.

  In addition, in the technique described in Patent Document 2, although there is a description related to a state of charge (SOC) estimation / detection method, there is no description about the SOC reflecting the deterioration (SOH) of the storage battery. Since the characteristics of storage batteries change under various deterioration conditions during long-term use, charging control that reflects these deteriorations is necessary. However, the technology described in Patent Document 2 charges charging that appropriately reflects deterioration. Can not do.

  The present invention has been made to solve these problems, and a charge / discharge control method capable of maintaining an electric storage device in an appropriate partial charge state by estimating the degree of deterioration and performing charge / discharge control, and An object is to provide a charge / discharge control device.

  1st aspect of the charging / discharging control method of the electrical storage device of this invention is the charging / discharging control method of the electrical storage device for maintaining in the partial charge state which can be charged and discharged, Comprising: Charging of the said electrical storage device was complete | finished Measure and store the voltage at the end of charging or the voltage at the end of discharging when the discharge ends, and when the state detection of the power storage device is requested, obtain a current measurement value of the power storage device and measure the current When the value is 0 or very small and it is determined that charging / discharging is substantially stopped, as the state detection mode 1, the power storage device is charged with a predetermined capacity (hereinafter referred to as pre-state detection charge), and the state detection is performed. The voltage measurement value of the electricity storage device when time t has elapsed since the end of pre-charging is acquired at a predetermined period, and a predetermined state quantity of the electricity storage device is estimated using the voltage measurement value to store the electricity storage Vice state detection is performed, a charge / discharge control command value of the power storage device is determined using the state detection result and the stored charge stop voltage and discharge stop voltage, and the power storage is determined from the current measurement value. When it is determined that the device is being charged / discharged, as the state detection mode 2, the state quantity last estimated in the state detection mode 1 and the stored charge stop voltage and discharge stop voltage are used. The charge / discharge control command value is determined, and charge / discharge control of the power storage device is performed according to the charge / discharge control command value.

  According to another aspect of the charge / discharge control method for an electricity storage device of the present invention, in the state detection mode 1, a relaxation function F (t (t) expressing a voltage change amount from a stable open circuit voltage (stable OCV) as a function of the state amount. ) Is optimally approximated by the measured voltage value, and the state quantity is estimated from the optimally approximated relaxation function F (t) to perform the state detection.

  In another aspect of the charge / discharge control method for an electricity storage device of the present invention, in the state detection in the state detection mode 1, the degree of deterioration for each reaction rate is estimated from the relaxation function F (t) as the state quantity, and the reaction Deterioration state due to deposition of lead sulfate on electrode plate, deterioration state due to concentration deviation of electrolyte on electrode plate, deterioration state due to liquid reduction Insufficient chargeable capacity and insufficient dischargeable capacity are estimated, and it is determined whether or not a preset threshold value is exceeded.

  According to another aspect of the charge / discharge control method for an electricity storage device of the present invention, in the state detection mode 1, when the deterioration state due to the liquid reduction is established, a liquid reduction alarm is output as the charge / discharge control command value, When the deterioration state due to the liquid is not established and the deterioration state due to the deposition of lead sulfate on the electrode plate or the deterioration state due to the concentration deviation of the electrolyte solution on the electrode plate surface is established, the charge / discharge control command value is charged at a high voltage. When the shortage of dischargeable capacity is satisfied and the shortage of chargeable capacity is not satisfied, a capacity adjustment charge is output as the charge / discharge control command value, and the shortage of chargeable capacity is satisfied and the dischargeable capacity is satisfied. When the shortage is not established, capacity adjustment discharge is output as the charge / discharge control command value.

  According to another aspect of the charge / discharge control method for an electricity storage device of the present invention, in the state detection in the state detection mode 2, a chargeable capacity shortage and a dischargeable capacity shortage are detected using the charge end voltage and the discharge end voltage. It is estimated and it is determined whether it exceeds the threshold value preset in each.

  According to another aspect of the charge / discharge control method for an electricity storage device of the present invention, in the state detection mode 2, when the shortage of dischargeable capacity is established and the shortage of chargeable capacity is not established, the charge / discharge control command value is a capacity. Adjusted charge is output, and when the shortage of chargeable capacity is satisfied and the shortage of dischargeable capacity is not satisfied, capacity adjustment discharge is output as the charge / discharge control command value.

  Another aspect of the charge / discharge control method for an electricity storage device of the present invention is characterized in that in the charge before state detection, the electricity storage device is charged at a 5% rated capacity.

  1st aspect of the charging / discharging control apparatus of the electrical storage device of this invention is a charging / discharging control apparatus of the electrical storage device for maintaining in the partial charge state which can be charged and discharged, Comprising: In order to input a state detection request signal The signal input means, the output display means for outputting predetermined information to the outside, and the charge end voltage when the charge of the power storage device is finished or the discharge end voltage when the discharge is finished are measured and stored. In addition, when the state detection request signal is input from the signal input means, the voltage measurement value and the current measurement value of the power storage device are input to detect the state of the power storage device, and the result of the state detection is stored. The charge / discharge control command value of the power storage device is determined using the voltage at the end of charge and the voltage at the end of discharge, and the result of the state detection and the charge / discharge control command value are displayed in the output A state detection unit for outputting a stage, characterized in that it comprises a charge and discharge control means for charging and discharging control the storage device by entering the charge and discharge control command value.

  The charge / discharge control apparatus for an electricity storage device according to another aspect of the present invention is characterized in that the state detection unit includes a state detection request switch for directly acquiring the state detection request signal. Storage device state detection device.

  ADVANTAGE OF THE INVENTION According to this invention, the charge / discharge control method and charge / discharge control apparatus which can maintain an electrical storage device in a suitable partial charge state by estimating deterioration and performing charge / discharge control can be provided.

It is a flowchart for demonstrating the outline of the charging / discharging control method of the electrical storage device which concerns on 1st Embodiment of this invention. It is a block diagram of the charging / discharging control apparatus of the electrical storage device of 1st Embodiment. It is a figure which shows typically the time change of the battery voltage when a voltage is applied to an accumulator from an external power supply. It is a figure which shows typically the time change of the battery voltage when connecting a load to a storage battery and discharging. It is a figure which shows typically the time change of an open circuit battery voltage. It is a schematic diagram for demonstrating the concentration deviation of the electrolyte solution of the electrode plate surface. It is a schematic diagram for demonstrating precipitation by the specific gravity difference of electrolyte solution. It is a schematic diagram for demonstrating the density | concentration change accompanying the reduction | decrease of electrolyte solution. It is a schematic diagram for demonstrating precipitation of lead sulfate to an electrode plate. It is explanatory drawing explaining the method of canceling the density | concentration unevenness of the electrolyte solution on the electrode plate surface. It is explanatory drawing explaining another method of canceling the density | concentration unevenness of the electrolyte solution of an electrode plate surface. It is explanatory drawing explaining the method to detect liquid reduction. It is explanatory drawing explaining the method to suppress precipitation of lead sulfate to an electrode plate. It is a flowchart which shows the method of calculating the determination value of a degradation state. It is a flowchart which shows the method of selecting charging / discharging control command value. It is explanatory drawing which shows the comparison with the conventional operating condition of an electrical storage device, and the operating condition in PSOC. It is a conceptual diagram for demonstrating the state detection required with respect to an electrical storage device.

  A charge / discharge control method and a charge / discharge control device for an electricity storage device according to a preferred embodiment of the present invention will be described in detail with reference to the drawings. In addition, about each structural part which has the same function, the same code | symbol is attached | subjected and shown for simplification of illustration and description. A charge / discharge control method and a charge / discharge control device for an electricity storage device according to the present invention include a liquid lead-acid battery mounted in an automobile, an electricity storage device used in combination with power generation by natural energy such as solar power generation or wind power generation, power failure It can be applied to a power storage device as a backup power source. Hereinafter, a liquid lead storage battery (hereinafter simply referred to as a storage battery) will be described as an example of the power storage device.

  First, the characteristics of the storage battery will be described below. The chargeable capacity (COA: Capability of Charge Acceptance), which is one of the important characteristics of a storage battery, is a charge capacity that can be stored in the storage battery as an increase in the energy level of charge or potential by external charging. Indicates. The change in battery voltage when charging the storage battery is shown in FIG. FIG. 3 schematically shows a time change of the battery voltage 23 when a power supply voltage 22 of 14.4 V is applied from an external power source to a storage battery having an initial battery voltage 21 of 12.8 V. When the battery voltage 23 reaches the power supply voltage 22, it cannot be charged any further.

  However, the voltage increase from the initial battery voltage 21 of the battery voltage 23 during charging is composed of an increase in the internal potential 24 of the storage battery (arrow A) and an increase due to the charging reaction resistance (arrow B). However, even when the voltage reaches almost the power supply voltage 22, the internal potential 24 is lower than the power supply voltage 22. Therefore, charging is possible until the internal potential 24 reaches the power supply voltage 22. However, since the difference between the battery voltage 23 and the power supply voltage 22 is small, the charging efficiency decreases. As described above, in a power storage device with an electrochemical reaction such as a lead storage battery, the chargeable capacity COA is determined by the power supply voltage 22, the internal potential 24 of the storage battery, and the charging reaction resistance.

  Next, the dischargeable capacity (COD: Capability of Discharge) which is another characteristic of the storage battery will be described below. The dischargeable capacity COD is a capacity that can be discharged to the outside while maintaining the battery voltage 23 at or above a predetermined voltage threshold. Here, the predetermined voltage threshold is a lower limit value of the voltage determined by the specifications of the system including the storage battery. FIG. 4 shows the change in battery voltage when the storage battery is discharged. FIG. 4 schematically shows a time change of the battery voltage 23 when the battery is discharged by connecting a load to a storage battery having an initial battery voltage 21 of 12.8V. The battery voltage 23 at the time of discharge decreases with time, but when it reaches the threshold voltage 25, it becomes a limit point where no further discharge is possible.

  Even in the change of the battery voltage 23 at the time of discharging the storage battery, the voltage drop from the initial battery voltage 21 is composed of a drop in the battery internal potential 24 (arrow C) and a drop due to the discharge reaction resistance (arrow D). Even if the internal potential 24 is higher than the threshold voltage 25, if the decrease due to the discharge reaction resistance is large, the limit point of the discharge capacity is reached. As described above, in an electricity storage device with an electrochemical reaction, the dischargeable capacity COD is determined by the internal potential 24 of the storage battery, the discharge reaction resistance, and the threshold voltage 25 defined by the system specifications.

  As shown in FIGS. 3 and 4, during charging / discharging of the storage battery, the battery voltage differs from the internal potential due to the charging reaction resistance or the discharge reaction resistance. The difference between the battery voltage and the internal potential decreases with time after stopping charging / discharging. FIG. 5 schematically shows the time change of the battery voltage in the open circuit state in which charging / discharging is stopped, that is, the open circuit battery voltage (OCV). As shown in the figure, the voltage increase 26 due to the charge reaction resistance and the voltage decrease 27 due to the discharge reaction resistance decrease after the charge / discharge stop, and the battery voltage converges to the internal potential 24.

  Since the internal potential of the storage battery is determined by the amount of relative ion concentration, when there is a bias in the electrolyte due to charging / discharging, there is a difference between the internal potential of the storage battery and the battery voltage obtained at the terminal of the storage battery. Arise. After charging / discharging is stopped, the battery voltage approaches the internal potential by a relaxation process in which the bias of the electrolyte accompanying charging / discharging shifts to a homogeneous state by diffusion. That is, in the relaxation process, a voltage change occurs due to the reaction resistance caused by the bias of the electrolyte accompanying charging / discharging, and this is added to the internal potential to become the battery voltage. Similarly, during charging / discharging, the voltage change due to the reaction resistance is added to the internal potential to obtain the battery voltage.

From the above, it is necessary to detect the chargeable capacity COA and the dischargeable capacity COD of the storage battery, including the charge reaction resistance and the discharge reaction resistance associated with the bias of the electrolyte inside the storage battery.
Next, Table 1 shows the factors that mainly affect the OCV, the chargeable capacity, and the dischargeable capacity among the state changes inside the storage battery that accompany charging and discharging of the liquid lead acid battery. Moreover, each factor is typically shown in FIGS. Table 1 conceptually shows the influence on each of the OCV, the voltage drop during discharging, and the voltage rise during charging, with respect to the four factors that affect the battery characteristics.

Table 1

  As shown in FIG. 6, the factor “(1)” shown in Table 1 “concentration unevenness of the electrolyte solution on the surface of the electrode plate” (hereinafter referred to as vertical stratification) is the concentration accumulated in the electrode plate 31. The sulfuric acid 32 oozes out from the electrode plate as it is charged, so that a concentration difference of the electrolytic solution 33 is formed along the surface of the electrode plate 31, which is a reversible change. When the electrolyte on the electrode plate has a high concentration, the OCV increases, the voltage drop during discharge increases, and the voltage increase during charging also increases. On the other hand, when the concentration of the electrolyte on the electrode plate surface is low, the OCV decreases, the voltage drop during discharge decreases, and the voltage increase during charging also decreases.

  The factor “2” in Table 1 “precipitation due to the difference in specific gravity of the electrolyte” (hereinafter referred to as lateral stratification) is shown in FIG. It is non-uniformly precipitated and is a reversible change. While sulfuric acid 34 is precipitated at the bottom of the storage battery, a water pool 35 is formed at the top of the storage battery. Since the reaction rate (ion transfer efficiency) decreases due to such non-uniformity of the electrolytic solution 33, when there is much precipitation, the OCV increases, the voltage drop during discharging increases, and the voltage increase during charging also increases. On the other hand, when there is little precipitation, OCV falls, the voltage drop at the time of discharge becomes small, and the voltage rise at the time of charge also becomes small.

  In addition, the factor “3) in Table 1 (concentration change accompanying the decrease in electrolyte solution” (hereinafter referred to as “liquid reduction”) is as shown in FIG. 8 from the normal state of FIG. The water in the electrolytic solution 33 is reduced and the electrolytic solution 33 is concentrated (FIG. 8B), and the cell unit becomes reversible when the solution is replenished. When the electrolytic solution 33 decreases (concentrates), the reaction rate (ion transfer efficiency) decreases. Therefore, when the electrolytic solution 33 is largely decreased, the OCV increases, the voltage drop during discharge increases, and the charge decreases. The voltage rise also increases. On the other hand, when the decrease in the electrolyte is small, it does not affect the OCV, the voltage drop during discharging, and the voltage increase during charging (normal).

  Further, the factor “precipitation of lead sulfate on the electrode plate” of (4) in Table 1 indicates that the discharge reaction product (lead sulfate PbSO 4) generated on the electrode plate surface by discharge as schematically shown in FIG. 36 remains on the surface of the electrode plate 31 without being extinguished by charging (FIG. 9B), and a part thereof is reversible. If the lead sulfate 36 remains on the surface of the electrode plate 31, the reaction surface area of the electrode plate 31 is reduced. Therefore, when the precipitation of the lead sulfate 36 is large, the OCV increases, the voltage drop during discharge increases, and the voltage rises during charging. Also grows. On the other hand, when there is little precipitation of lead sulfate 36 (FIG. 9A), it does not affect the OCV, the voltage drop during discharge, and the voltage rise during charge (normal).

  The relationship between the deterioration characteristics of the storage battery due to the factors shown in Table 1 and charge / discharge control will be described in detail below. First, when the vertical stratification of (1) in Table 1 is formed, the charging reaction resistance increases and the COA decreases during charging. A method for eliminating such vertical stratification will be described with reference to FIG. In FIG. 10, in the vertically stratified state shown in FIG. 10A, by applying a voltage equal to or higher than the water decomposition voltage between the terminals of the storage battery, the water of the electrolytic solution 33 is decomposed to generate gas 37 (gassing). (FIG. 10B). Such unevenness of the collar 33 can be eliminated (FIG. 10C).

  However, when liquid reduction, which is the cause of (3) in Table 1, has already occurred, performing high voltage charging that causes electrolysis of water generates gas 37 more than normal gassing, Problems such as hydrogen explosion and other problems such as shortening the life of the storage battery due to exposure of the electrode plate 31 from the electrolyte solution 33 occur. Therefore, in order to stably operate a storage battery and a system equipped with the storage battery, it is not preferable to frequently perform high voltage charging.

  Alternatively, as another method for eliminating vertical stratification, as shown in FIG. 11, by performing discharge in a storage battery in which vertical stratification is formed, the charge reaction resistance B caused by the bias of the electrolyte due to the charge reaction is reduced. A method of lowering the charging reaction resistance B by canceling with the discharging reaction resistance D caused by the bias of the electrolytic solution due to the discharging reaction is also conceivable. However, performing such discharge not only lowers the charging reaction resistance B but also lowers the internal potential 24 of the storage battery, and may not be able to maintain the necessary discharge capacity. Therefore, in order to stably operate the storage battery and the system on which the storage battery is mounted, it is not preferable to discharge frequently.

  Next, the relationship between the deterioration characteristics of the storage battery due to lateral stratification shown in Table 1 and charge / discharge control will be described. When the lateral stratification is formed, the change in the battery voltage accompanying the relaxation after charging as shown in FIG. 4 is detected by deviating from the original reference internal potential due to the influence of the bias of the electrolyte. This causes an increase in error factors when determining the internal characteristics of the battery. As a method of eliminating such lateral stratification, there is a method of eliminating the unevenness of the electrolyte by stirring the electrolyte by generating gas by gassing shown in FIG. However, as in the case of eliminating vertical stratification, the life of the storage battery is shortened by exposure to dangers such as hydrogen explosion due to the generation of gas more than usual due to the decrease in electrolyte, or exposure of the electrode plate from the electrolyte. Problems arise. Therefore, in order to stably operate a storage battery and a system equipped with the storage battery, it is not preferable to frequently perform high voltage charging.

  Next, the relationship between the deterioration characteristics of the storage battery due to liquid reduction and charge / discharge control shown in (1) of Table 1 will be described below. When the storage battery is depleted, the electrolyte concentration inside the storage battery is continuously maintained at a higher level than usual, which increases the internal potential of the storage battery and the battery voltage, reducing the efficiency of the charge and discharge reactions. End up. This becomes an error factor of various parameters of the storage battery calculated based on the battery voltage, and causes a decrease in characteristics of COA and COD. In addition, if high-voltage charging is performed in a liquid-reduced state, there are problems such as hydrogen explosion due to generation of more gas than usual, and shortening the life of the storage battery due to the electrode plate being exposed from the electrolyte. There is a problem that occurs. Therefore, it is desirable to output an alarm requesting replenishment work or replacement of the storage battery when the liquid reduction is detected.

  As a general method for detecting the reduced liquid state of the storage battery, as illustrated in FIG. 12, a sensor 38 for measuring the refractive index, specific gravity, or ion concentration of the electrolytic solution is provided in the electrolytic solution 33 of each cell 39 in the storage battery. There is a method of inserting and detecting liquid reduction based on the measurement result by the sensor 38. However, if a sensor 38 is provided for each cell 39 in the storage battery to detect liquid reduction, there is a problem that the state detection becomes complicated and the cost increases.

  Further, the relationship between the deterioration characteristics of the storage battery due to the deposition of lead sulfate and charge / discharge control shown in (1) of Table 1 will be described below. Ideally, the lead sulfate deposited on the surface of the electrode plate by discharge is reduced to lead or lead oxide by charging, so that the reaction is reversible. However, in actual storage batteries, all lead sulfate is not reduced due to various factors such as particle size distribution, conductive path, and electrolyte concentration unevenness. A part is accumulated without being reduced.

  As lead sulfate that is not reduced by discharge grows, the electrical conductivity inside the storage battery decreases and the reaction area on the electrode plate surface decreases, reducing the efficiency of the charge reaction and discharge reaction. This causes a decrease in COD characteristics.

  As means for suppressing such lead sulfate enlargement, there is a method of charging a storage battery at a high voltage as shown in FIG. The high voltage charging makes it possible to partially dissolve the lead sulfate 36 shown in FIG. 13B, which could not be dissolved by normal charging (FIG. 13C), and restore the COA and COD characteristics of the storage battery. Can be made. However, when high voltage charging is performed in a liquid-reduced state, there are problems such as hydrogen explosion due to generation of more gas than usual, and problems such as shortening the life of the storage battery due to the electrode plate 31 being exposed from the electrolytic solution 33. This is not a favorable operating condition.

  Therefore, in the storage battery charge / discharge control method and charge / discharge control apparatus of the present invention, a storage battery having a deterioration state that progresses at two or more different reaction rates can be evaluated by distinguishing and evaluating deterioration factors for each reaction rate. Stable charge / discharge control can be performed by accurately calculating COD and SOH and using this to maintain the storage battery in a preferable partially charged state.

Table 2 shows the respective relaxation rates and charge / discharge control methods for improving the characteristic deterioration due to each factor for the factors in Table 1 that affect the characteristics of the storage battery. In Table 2, the relaxation rate of a liquid lead-acid battery having a capacity of 50 [Ah] is shown as an example.
Table 2

  (1) Longitudinal stratification can be improved by performing high-voltage charging or capacity adjustment discharging when the relaxation rate is within a few minutes and the electrolyte concentration on the electrode plate surface is high. (2) The lateral stratification can be improved by performing high-voltage charging when the relaxation rate is about several hours and there is much precipitation due to the difference in specific gravity of the electrolyte. (3) The liquid reduction does not relax even if left untreated, and it is preferable to perform an alarm output or the like for notifying this. (4) The precipitation of lead sulfate can be improved by performing high-voltage charging when the relaxation rate is several seconds or less and the amount of precipitation is large.

  In order to suitably perform charge / discharge control in the partially charged state, it is not preferable to charge the storage battery at a high voltage in the liquid-reduced state or to discharge for capacity adjustment in a state where the discharge capacity is reduced. Therefore, in the storage battery charge / discharge control method and charge / discharge control apparatus of the present invention, the state of the storage battery is detected to estimate the deterioration due to each factor, and the stable OCV, the discharge end voltage, and the charge end voltage are stored. By using these to estimate the chargeable capacity COA and the dischargeable capacity COD of the storage battery, charge / discharge control can be performed so as to maintain the storage battery in a suitable partially charged state.

(First embodiment)
A charge / discharge control method and a charge / discharge control device for an electricity storage device according to a first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a flowchart for explaining an outline of a charge / discharge control method for an electricity storage device according to the present embodiment, and FIG. 2 is a block diagram of a charge / discharge control device for the electricity storage device according to the present embodiment.

  The charge / discharge control apparatus 100 of the present embodiment is provided in the power storage device mounting system 10 to detect the state of the storage battery 11 and controls the storage battery to a suitable partially charged state based on the result of the state detection. In addition to the charge / discharge control device 100 and the storage battery 11, the storage device mounting system 10 includes a charger 12 and a discharge load 13 connected to the storage battery 11, and a measurement unit 14 that measures the voltage, current, and the like of the storage battery 11. Yes.

  The charge / discharge control apparatus 100 includes a signal input unit 101, an output display unit 102, a state detection unit 103, and a charge / discharge control unit 104. The signal input means 101 is used to input a signal for requesting the state detection of the storage battery 11 (hereinafter referred to as a state detection request signal). For example, when the system administrator requests the state detection of the storage battery 11, a state detection request signal is input from the signal input unit 101. In the present embodiment, a state detection request switch 103a is provided in the state detection unit 103 as another means for inputting a state detection request signal. The state detection request switch 103a is provided so that a maintenance staff or the like can promptly request the state detection of the storage battery 11 during maintenance, separately from the state detection requested by the system administrator during normal times.

  The output display unit 102 is used to notify the system administrator of information on state detection and charge / discharge control performed by the state detection unit 103. Both the signal input means 101 and the output display means 102 are preferably provided in a place that is easily accessible by the system administrator. When the storage battery 11 is an in-vehicle storage battery, the driver's seat that can be easily accessed by the driver or in the vicinity thereof is desirable. It is good to provide.

  The state detection unit 103 inputs the measurement values such as the voltage and current of the storage battery 11 from the measuring unit 14 and performs state detection, and the voltage measurement value at the end of charging or at the end of discharging is used as the voltage at the end of discharging or at the end of discharging. Save as voltage. Furthermore, a voltage measurement value when a predetermined time has elapsed after the end of charge / discharge is stored as a stable OCV. When a state detection request signal is input from the signal input means 101 or the state detection request switch 103a, the state detection unit 103 inputs this to detect the state of the storage battery 11, and based on the result, a suitable partial charge The charge / discharge control for transitioning to the state is determined.

  When the state detection request signal is input, the state detection unit 103 performs state detection using the measured voltage value of the storage battery 11, the stored discharge end voltage, the discharge end voltage, and the stable OCV, and performs necessary charge / discharge control. Determine. The determination result of the state detection and the charge / discharge control is displayed on the output display unit 102, and the determination result of the charge / discharge control is output to the charge / discharge control unit 104. The charge / discharge control unit 104 causes the charger 12 or the discharge load 13 to perform predetermined charge / discharge control based on the determination result of the charge / discharge control input from the state detection unit 103.

  In addition, the communication means between the state detection unit 103 and the signal input means 101, the output display means 102, the charge / discharge control means 104, and the measurement means 14, and the charge / discharge control means 104, the charger 12 and the discharge load 13 Various digital or analog communication buses can be used as the communication means.

  In the charge / discharge control apparatus 100 of the present embodiment, the state detection unit 103 has two types of state detection mode processes. The first state detection mode is state detection (hereinafter referred to as state detection mode 1) performed when charging / discharging of the storage battery 11 is stopped or only a minute current is flowing, and the second state detection mode is This is state detection performed when the storage battery 11 is being charged / discharged (hereinafter referred to as state detection mode 2).

  The state detection unit 103 inputs the current measurement value of the storage battery 11 from the measurement unit 14 and uses this to determine whether the storage battery 11 is in charge / discharge stop or charge / discharge. When the measured current value is 0 or very small, it is determined that charging / discharging is substantially stopped, and otherwise, it is determined that charging / discharging is being performed. When the measured current value is very small, it is determined that the storage battery mounted system 10 is in a stopped state and only a small dark current is supplied from the storage battery 11 to the instrument or the like. When it is determined that charging / discharging is stopped, the state detection unit 103 performs state detection mode 1 processing, and when it is determined that charging / discharging is in progress, processing of state detection mode 2 is performed.

  In the state detection mode 1, the storage battery 11 is charged with a predetermined capacity (hereinafter referred to as pre-state detection charging) before the state detection, and then the voltage measurement value of the storage battery 11 is input at a predetermined cycle to detect the state. I do. In the pre-state detection charging, the state detection unit 103 requests the charging / discharging control unit 104 to charge a predetermined capacity, and the charging / discharging control unit 104 controls the charger 12 in accordance with this to perform charging. On the other hand, in the state detection mode 2, state detection is performed using limited data without performing pre-state detection charging.

  In the charge / discharge control device 100 shown in FIG. 2, it is also possible for a maintenance person or the like to perform the above-described pre-state detection charging. When maintenance personnel or the like use the state detection request switch 103a to detect the state of the storage battery 11 during maintenance, when the state detection request switch 103a is turned on, a message or the like requesting charging before state detection is sent to the output display means 102. Display. As a result, a maintenance worker or the like connects the external charger 21 to the storage battery 11 and performs charging with a predetermined capacity.

  After detecting the state of the storage battery 11 in the state detection mode 1 or the state detection mode 2, the state detection unit 103 determines charge / discharge control for shifting the storage battery 11 to a suitable partial charge state based on the result. To do. The determination result of the charge / discharge control is displayed on the output display unit 102 and is output to the charge / discharge control unit 104. The charge / discharge control unit 104 controls the charger 12 or the discharge load 13 based on the charge / discharge control command value input from the state detection unit 103 to charge or discharge the storage battery 11. Thereby, the storage battery 11 is transferred to a suitable partially charged state. At the time of maintenance, a maintenance staff or the like connects the external charger 21 or the external discharge load 22 to the storage battery 11 based on the determination result of the charge / discharge control displayed on the output display means 102 to charge or discharge a predetermined capacity. I do.

  In the charge / discharge control apparatus 100, the flow of processing performed according to the charge / discharge control method of the present embodiment will be described in more detail with reference to the flowchart shown in FIG. In the charge / discharge control method of this embodiment, first, a state detection request signal is input from the signal input means 101, and the state detection unit 103 inputs this (step S1). Thereby, the state detection part 103 inputs the electric current measurement value of the storage battery 11 from the measurement means 14 at step S2, and determines whether the selection conditions of the state detection mode 1 are satisfied using this electric current measurement value at step S3. To do. The selection condition of this state detection mode 1 includes at least a condition that the current measurement value of the storage battery 11 is 0 or very small and is substantially in a charge / discharge stop state.

  If it is determined in step S3 that the selection condition for the state detection mode 1 is satisfied, the state detection unit 103 performs the process for the state detection mode 1 (steps S4 to S6), while the selection condition for the state detection mode 1 is If it is determined that the condition is not established, the state detection unit 103 performs a state detection mode 2 process (steps S7 to S10). As a process in the state detection mode 1, in step S4, the storage battery 11 is charged before state detection. When the pre-state detection charging is completed, the state of the storage battery 11 is detected in step S5. Then, the result of the state detection is displayed on the output display means 102 in step S6.

  On the other hand, in the process of the state detection mode 2, the SOH calculated in the previous state detection mode 1 is read from a predetermined storage unit (not shown) in step S7, and is stored in the predetermined storage unit so far in step S8. Read the stored charge end voltage and discharge end voltage. Then, a limited state detection of the storage battery 11 is performed in step S9 from the previously calculated SOH, the charge end voltage, and the discharge end voltage. The result of the state detection is displayed on the output display means 102 in step S10.

  When the state detection of the storage battery 11 in the state detection mode 1 or the state detection mode 2 is performed, in step S11, charge / discharge control necessary to shift the storage battery 11 to a predetermined partial charge state based on the result of the state detection. A command value is created, and the charge / discharge control command value information is displayed on the output display means 102 in step S12, and the charge / discharge control command value is displayed on the charge / discharge control means 104. In step S13, the charge / discharge control means 104 controls the charger 12 or the discharge load 13 according to the charge / discharge control command value to charge or discharge a predetermined capacity. Thereby, the storage battery 11 is maintained in a desired partially charged state.

  The charge / discharge control command value created in step S11 is created based on the deterioration state of the storage battery 11 determined by the state detection in the state detection mode 1 or the state detection mode 2. The deterioration state of the storage battery 11 determined in the present embodiment includes the four types shown in Table 2, and includes other failures as other deterioration states.

  The state detection unit 103 estimates SOH corresponding to these deterioration states, and determines whether the COD and COA of the storage battery 11 are appropriate based on this. Furthermore, based on the results of SOH, COD, and COA of the storage battery 11, the charge amount by the charger 12 or the discharge amount to the discharge load 13 is calculated as a charge / discharge control command value.

  When the charge / discharge control means 104 receives the charge / discharge control command value from the state detection unit 103, the charge / discharge control means 104 performs the following processing according to the charge / discharge control command value. That is, when the charge / discharge control command value is charging, a command value for performing predetermined charging is output to the charger 12. When the charge / discharge control command value is discharge, a command value for causing predetermined discharge is output to the output discharge load 13.

  Next, the state detection method of the storage battery 11 performed in the state detection mode 1 in the state detection unit 103 will be described. In the state detection mode 1, after the operation of the power storage device mounted system 10 is stopped and charging / discharging from the storage battery 11 is stopped, charging before a state detection is performed in which charging of a predetermined capacity is performed before the state detection of the storage battery 11 is started. Is done. Thereby, in the state detection mode 1, the state detection in the transient change which shows the same tendency after charge will always be performed, and it becomes possible to determine the deterioration state of the storage battery 11 with high precision. Since the transient change after the completion of the charge before the state detection of the storage battery 11 includes processes with different reaction rates, in order to determine the charge / discharge capability of the storage battery 11 after the charge / discharge stop with high accuracy, the reaction It is preferable to use a method of detecting a state by evaluating a state change for each speed. An example of such a state detection method will be described below.

A battery voltage change amount ΔV (t) after stopping charging / discharging is expressed as a function (hereinafter referred to as a relaxation function) F (m is a polynomial function fi (t) (i = 1 to m) corresponding to different reaction rates. It can be expressed as follows using t).
ΔV (t) = F (t)
= F1 (t) + f2 (t) + ... fm (t) = Σfi (t) (1)

The voltage change amount ΔV (t) in the formula (1) is the voltage measurement value Vmes (t) when the time t has elapsed from the end of the pre-state detection charging, and a sufficient time (for example, 20 hours) after the charge / discharge stop. The difference from the stable voltage at the time of stoppage (hereinafter referred to as OCV20hr) when it becomes substantially constant. The initial value of the stable voltage OCV20hr at the time of stop can be used by reading the stable OCV stored in a predetermined storage unit. The voltage change amount ΔV (t) can be expressed as the following equation as a change amount from the stop-time stable voltage OCV20hr.
ΔV (t) = Vmes (t) −OCV20hr (2)

  In the relaxation function F (t), each term fi (t) represents the contribution to the voltage change in the relaxation process with different reaction rates of the storage battery 11, and hereinafter, the relaxation function fi (t) for each reaction rate and To do. The relaxation function fi (t) for each reaction rate is a function that depends on the deterioration degree SOH, which is the state quantity of the storage battery 11, the remaining capacity SOC (ion concentration), and the temperature T. A voltage change amount ΔV (t) is calculated from the voltage measurement value Vmes (t), and the equation (1) is optimized using the voltage change amount ΔV (t), whereby each reaction rate relaxation function fi (t ) Can be determined.

The state detection method used in the charge / discharge control method of this embodiment inputs a voltage measurement value of the storage battery 11 at a predetermined cycle after the completion of the pre-state detection charging, and every time the voltage measurement value is input, the relaxation function F (t). It has been updated with optimizations. When the relaxation function for each reaction rate when optimized using the voltage measurement value input at the n-th time is defined as fin (t), fin (t) can be expressed by the following equation.
fin (t) = firef (t) * {SOCn / SOCref}
* {SONi / SOHiref} * G (T) (3)

  In equation (3), firef (t), SOCref, and SOHiref represent the relaxation function for each reaction rate, the remaining capacity, and the degree of deterioration for each reaction rate in a predetermined reference state, respectively, and G (T) represents the storage battery voltage. The dependence on the temperature T is shown. The remaining capacity SOCn and the deterioration rate SOIn for each reaction rate can be calculated from Equation (3) using fin (t) as a relaxation function for each reaction rate estimated using the nth voltage measurement value.

In the state detection mode 1, the relaxation function fin (t) for each reaction rate is obtained, and the relaxation function for each reaction rate fin (t) corresponding to the relaxation rate of each deterioration factor shown in Table 2 is stored in a predetermined storage unit. From the stored stable OCV (referred to as OCVa), charge end voltage (referred to as Va), and discharge end voltage (referred to as Vb), determination values of the deterioration states SOHa to SOHF shown below can be calculated. it can.
(1) SOHa: State of deterioration due to precipitation of lead sulfate on the electrode plate (2) SOHb: State of deterioration due to vertical stratification (3) SOHc: State of deterioration due to liquid reduction (4) SOHd: Insufficient chargeable capacity (5) SOHe : Insufficient dischargeable capacity (6) SOHf: Other failure In the following, the calculation method of each judgment value of the deteriorated states SOHa to SOOHf will be described in detail with reference to FIG. FIG. 14 is a flowchart illustrating a method for calculating the determination values of the deterioration states SOHa to SOOHf.

  SOHa shows a deterioration state due to precipitation of lead sulfate on the electrode plate, and Table 2 responds to the charging reaction at a very fast relaxation rate of several seconds or less. From the relaxation function for each reaction rate (fa) corresponding to this relaxation rate and the voltage Va at the end of charging, as shown in FIG. 14A, a function ga (fa, Va) created in advance is used. SOHa is calculated (step S21). Alternatively, instead of the function ga (fa, Va), SOHa may be calculated in a table format using the reaction rate relaxation function fa and the charging end voltage Va as parameters. The calculated SOHa is compared with a predetermined threshold value THa (step S22), and when exceeding this, it is determined that the deterioration state due to the deposition of lead sulfate on the electrode plate is established (step S23), otherwise it is not established. Determination is made (step S24).

  SOHb shows a deterioration state due to vertical stratification, and responds to the charging reaction at a relaxation rate within several minutes from Table 2. As shown in FIG. 14B, SOHb is calculated from the relaxation function for each reaction rate corresponding to this relaxation rate (referred to as fb) using a function gb (fb) created in advance (step S25). Alternatively, SOHb may be calculated in a table format using the reaction rate relaxation function fb as a parameter instead of the function gb (fb). The calculated SOHb is compared with a predetermined threshold value THb (step S26). When the calculated SOHb is exceeded, it is determined that the deterioration state due to vertical stratification is established (step S27), and otherwise, it is determined that it is not established (step S28). ).

  SOHc indicates a deterioration state due to liquid reduction, and since the concentration of the entire electrolytic solution is changed, changes appear in the overall relaxation rate F (t), the stable OCV, and the charging end voltage. From the overall relaxation rate F (t), stable OCV (OCVa), and charging end voltage Va, as shown in FIG. 14C, using a function gc (F, OCVa, Va) created in advance. SOHc is calculated (step S29). Alternatively, instead of the function gc (F, OCVa, Va), the SOHc is calculated in a table format using the overall relaxation rate F (t), the stable OCV (OCVa), and the charging end voltage Va as parameters. Also good. The calculated SOHc is compared with a predetermined threshold THc (step S30), and if it exceeds this, it is determined that the deterioration state due to liquid reduction is established (step S31), and otherwise, it is determined that it is not established (step S32). .

  SOHd indicates a deterioration state due to a shortage of chargeable capacity, and its influence appears on the voltage at the end of charging. As shown in FIG. 14D, SOHd is calculated from the charging end voltage Va using a function gd (Va) created in advance (step S33). Or, instead of the function gd (Va), SOHd may be calculated in a table format using the voltage Va at the end of charging as a parameter. The calculated SOHd is compared with a predetermined threshold value THd (step S34), and if it exceeds this, it is determined that insufficient chargeable capacity is established (step S35), and otherwise, it is determined that it is not established (step S36).

  SOHe indicates a deteriorated state due to a lack of dischargeable capacity, and its influence appears on the voltage at the end of discharge. As shown in FIG. 14E, SOHe is calculated from the discharge end voltage Vb using a function ge (Vb) created in advance (step S37). Alternatively, SOHe may be calculated in a table format using the discharge end voltage Vb as a parameter instead of the function ge (Vb). The calculated SOHe is compared with a predetermined threshold value THe (step S38), and if it exceeds this, it is determined that chargeable capacity shortage is established (step S39), and otherwise, it is determined that it is not established (step S40).

  SOHf indicates a deterioration state due to a failure other than the above, a failure in which charging / discharging of the storage battery 11 cannot be performed normally, a state detection error in which a measured value or a calculated value is outside an allowable range, or a charge / discharge control device This is established when a failure of the device itself that makes it impossible for 100 to perform normal output, an abnormal output due to another deterioration mode unique to the storage battery 11, or the like is detected.

  In the determination of the deterioration states SOHa to SOHf, the threshold values THa to THf are provided and compared one by one. However, the present invention is not limited to this, and for example, two or more threshold values THa to THf are provided. You may make it perform determination of the above deterioration state.

In the state detection mode 1, when the determination values of the deterioration states SOHa to SOOHf are calculated, the following charge / discharge control command value is selected using the calculated determination values.
(1) Cha1: Normal (2) Cha2: Capacity adjustment charge (3) Cha3: Capacity adjustment discharge (4) Cha4: High voltage charge (5) Cha5: Low liquid alarm (6) Cha6: Other abnormal alarm

  A method for selecting the charge / discharge control command values Cha1 to Cha6 from the determination values of the deterioration states SOHa to SOHF will be described below with reference to FIG. FIG. 15 is a flowchart showing a method for selecting the charge / discharge control command values Cha1 to Cha6. First, in step S41, it is determined whether or not a deterioration state due to liquid reduction (SOHc) is established. If it is established, a charge / discharge control command value of a “liquid reduction alarm” (Cha5) is output in step S42. . If it is determined in step S41 that SOHc is not established, the process proceeds to step S43.

  In step S43, it is determined whether a deterioration state (SOHa) due to precipitation of lead sulfate on the electrode plate or a deterioration state (SOHb) due to vertical stratification is established, and when at least one of them is established. In step S44, a charge / discharge control command value of “high voltage charge” (Cha4) is output. If it is determined in step S43 that neither SOHa nor SOHb is established, the process proceeds to step S45.

  In step S45, it is determined whether or not the dischargeable capacity shortage (SOHe) is satisfied. If it is satisfied, it is determined in step S46 whether or not the chargeable capacity shortage (SOOHd) is satisfied. As a result, if it is determined that SOHd is not established, a charge / discharge control command value of “capacity adjustment charging” (Cha2) is output in step S47. If it is determined in step S45 that SOHe is not established, the process proceeds to step S48.

  In step S48, it is determined whether or not a chargeable capacity shortage (SOHd) is established, and if established, a charge / discharge control command value of “capacity adjustment discharge” (Cha3) is output in step S49. In this case, since it is confirmed in step S45 that the dischargeable capacity shortage (SOHe) is not established, the charge / discharge control command value of “capacity adjustment discharge” (Cha3) can be output. If it is determined in step S48 that SOHd is not established, the process proceeds to step S50.

  In step S50, it is determined whether or not another failure (SOHf) has been established. If it has been established, the charge / discharge control command value of “other abnormality alarm” (Cha6) is output in step S51. Further, if it is determined in step S50 that SOHf is not established, since no deterioration state is established, a “normal” (Cha1) charge / discharge control command value is output in step S52. When it is determined in step S47 that SOHd is established, since the dischargeable capacity shortage (SOHe) and the chargeable capacity shortage (SOHd) are both established, the “other abnormal alarm” in step S51 is used here. The charge / discharge control command value of (Cha6) is output. For example, a charge / discharge control command value of “insufficient discharge capacity and insufficient charge capacity” may be output.

  On the other hand, when the selection condition of the state detection mode 1 is not satisfied and the process of the state detection mode 2 is performed, the SOH, the charge end voltage, and the discharge end voltage calculated in the previous state detection mode 1 are used. The limited state detection of the storage battery 11 is performed. In this case, since the relaxation function of the equation (1) cannot be calculated with high accuracy, the deterioration determination using the reaction rate relaxation function fi (t) cannot be performed. Therefore, in the state detection mode 2, only the deterioration state of SOHd, SOHe, and SOOHf that does not use the relaxation function fi (t) for each reaction rate is detected.

  As explained using the above embodiment, according to the charge / discharge control method and charge / discharge control device for an electricity storage device of the present invention, the charge / discharge control is performed by accurately estimating the deterioration degree of the electricity storage device when charge / discharge is stopped. In addition, by performing limited charge / discharge control even during charge / discharge, it becomes possible to maintain the power storage device in an appropriate partial charge state.

  In addition, the description in this Embodiment shows an example of the charging / discharging control method and charging / discharging control apparatus of the electrical storage device which concerns on this invention, and is not limited to this. The detailed configuration and detailed operation of the charge / discharge control method and the charge / discharge control apparatus for the power storage device in the present embodiment can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Storage device mounting system 11 Storage battery 12 Charger 13 Discharge load 14 Measuring means 100 Charge / discharge control apparatus 101 Signal input means 102 Output display means 103 State detection part 103a State detection request switch 104 Charge / discharge control means

Claims (9)

A charge / discharge control method for an electricity storage device for maintaining a partially charged state capable of being charged and discharged,
Measuring and storing the voltage at the end of charging when the charging of the electricity storage device is completed or the voltage at the end of discharging when ending the discharge,
When the state detection of the electricity storage device is requested,
When the current measurement value of the electricity storage device is acquired and the current measurement value is 0 or minute and it is determined that charging / discharging is substantially stopped,
As state detection mode 1, charging of the electricity storage device with a predetermined capacity (hereinafter referred to as pre-state detection charge), and a voltage measurement value of the electricity storage device when time t has elapsed since completion of the pre-state detection charge Is obtained at a predetermined cycle, and the state measurement of the power storage device is performed by estimating a predetermined state quantity of the power storage device using the voltage measurement value, and the result of the state detection and the stored voltage at the time of charging stop And determining the charge / discharge control command value of the electricity storage device using the discharge stop voltage,
When it is determined that the electricity storage device is being charged / discharged from the current measurement value,
As the state detection mode 2, determine the charge / discharge control command value using the state quantity last estimated in the state detection mode 1 and the stored charge stop voltage and discharge stop voltage,
A charge / discharge control method for an electricity storage device, wherein charge / discharge control of the electricity storage device is performed according to the charge / discharge control command value. In the state detection mode 1, the relaxation function F (t) representing the amount of voltage change from the stable open circuit voltage (stable OCV) as a function of the state amount is optimally approximated by the voltage measurement value, and the optimal approximation is performed. The charge / discharge control method for an electricity storage device according to claim 1, wherein the state detection is performed by estimating the state quantity from a relaxation function F (t). In the state detection in the state detection mode 1, the degree of deterioration for each reaction speed is estimated from the relaxation function F (t) as the state quantity, the degree of deterioration for each reaction speed, the voltage at the end of charging, and the time at the end of discharging. Estimate the deterioration state due to the deposition of lead sulfate on the electrode plate, the deterioration state due to the concentration deviation of the electrolyte on the electrode plate, the deterioration state due to liquid reduction, the lack of chargeable capacity, and the lack of dischargeable capacity using voltage The charge / discharge control method for an electricity storage device according to claim 2, wherein it is determined whether or not a predetermined threshold value is exceeded. In the state detection mode 1,
When the deterioration state due to the liquid reduction is established, a liquid reduction alarm is output as the charge / discharge control command value,
When the deterioration state due to the liquid reduction does not hold and the deterioration state due to the deposition of lead sulfate on the electrode plate or the deterioration state due to the concentration deviation of the electrolyte solution on the electrode plate surface holds, the charge / discharge control command value is high. Output voltage charge,
When the dischargeable capacity shortage is satisfied and the chargeable capacity shortage is not satisfied, the capacity adjustment charge is output as the charge / discharge control command value,
4. The charge / discharge control method for an electricity storage device according to claim 3, wherein when the chargeable capacity shortage is satisfied and the dischargeable capacity shortage is not satisfied, capacity adjustment discharge is output as the charge / discharge control command value. . In the state detection in the state detection mode 2, whether the chargeable capacity shortage and the dischargeable capacity shortage are estimated using the voltage at the end of charge and the voltage at the end of discharge and whether or not a preset threshold value is exceeded. The charge / discharge control method for an electricity storage device according to claim 1, wherein: In the state detection mode 2,
When the dischargeable capacity shortage is satisfied and the chargeable capacity shortage is not satisfied, the capacity adjustment charge is output as the charge / discharge control command value,
6. The charge / discharge control method for an electricity storage device according to claim 5, wherein when the chargeable capacity shortage is established and the dischargeable capacity shortage is not established, capacity adjustment discharge is output as the charge / discharge control command value. . The charge / discharge control method for an electricity storage device according to claim 1, wherein in the charge before state detection, the electricity storage device is charged with a 5% rated capacity. A charge / discharge control device for an electricity storage device for maintaining a partially charged state capable of being charged and discharged,
A signal input means for inputting a state detection request signal;
Output display means for outputting predetermined information to the outside;
Measuring and storing the voltage at the end of charging when charging of the power storage device is completed or the voltage at the time of discharging completion when discharging is completed, and inputting the state detection request signal from the signal input means, the power storage device The voltage measurement value and the current measurement value are input to detect the state of the power storage device, and the charge / discharge of the power storage device is performed using the state detection result and the stored charge end voltage and discharge end voltage. A state detection unit for determining a control command value and outputting the result of the state detection and the charge / discharge control command value to the output display means;
Charge / discharge control apparatus for an electricity storage device, comprising: charge / discharge control means for inputting and supplying the charge / discharge control command value to control charge / discharge of the electricity storage device. The charge / discharge control apparatus for an electricity storage device according to claim 8, wherein the state detection unit includes a state detection request switch for directly acquiring the state detection request signal.

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