JP2014127404A - Method for replacing battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for replacing a battery pack, capable of preventing non-uniformity of electric cells constituting a battery pack, with a simple method and furthermore without causing loss.SOLUTION: A method for replacing a battery pack that is constituted such that a plurality of secondary batteries as electric cells are connected in series includes: a determination step (steps S11-S13) of determining the degree of deterioration of each of the electric cells connected in series; a specification step (step S16) of specifying an electric cell in which deterioration has relatively taken place more than other electric cells, on the basis of results obtained in the determination step; and a replacing step (step 17) of replacing the electric cell which has been specified by the specification step and in which deterioration has relatively taken place.

Description

  The present invention relates to an assembled battery replacement method.

  In Patent Document 1, the degradation state of a plurality of battery modules constituting a used battery taken over at the time of battery replacement is measured, and a rank is assigned to each battery module based on the measurement result. A technique is disclosed in which a battery module having a rank that satisfies a replacement request is searched from a battery database according to the replacement request, and a replacement battery that satisfies the replacement request is configured by combining the searched battery modules. According to this technique, the replacement battery can be configured by combining a plurality of battery modules in consideration of the deterioration state, and therefore the potential of the battery can be effectively utilized.

  By the way, in the technique shown in Patent Document 1, replacement is performed in units of battery modules. As shown in Patent Document 1, the battery module is configured by connecting a plurality of single cells in series. However, aging does not occur uniformly for all the single cells, but occurs nonuniformly. For this reason, although the other single cells connected in series are less deteriorated, there is a case where it is necessary to replace the entire battery module because the deterioration of a specific single cell has progressed.

  In view of this, a technique disclosed in Patent Document 2 has been proposed in order to prevent the cells from being deteriorated unevenly. The technology disclosed in Patent Document 2 includes a plurality of protection units that are provided corresponding to the respective battery modules and configured to operate using the corresponding battery modules as power sources, and each of the protection units has its own current consumption. A measurement unit for measuring the discharge unit, a discharge unit SW for discharging the corresponding battery module, and a control unit for controlling the discharge unit so that the sum of the consumption current and the discharge current by the discharge unit becomes a constant value between the protection units. ing. With such a configuration, it is possible to extend the life of the assembled battery by suppressing variations in the state of charge between the single cells.

JP 2010-172122 A JP 2008-245481 A

  By the way, in the technique disclosed in Patent Document 2, since the voltage is measured and controlled in units of single cells, the configuration becomes complicated. In addition, since the battery module is discharged through the resistor, there is a problem that power loss occurs.

  The present invention has been made in view of the situation as described above, and is an assembled battery capable of eliminating the non-uniformity of the cells constituting the assembled battery by a simple method and without causing loss. It is to provide an exchange method.

In order to solve the above-described problems, the present invention provides a method for replacing an assembled battery in which secondary batteries as a plurality of unit cells are connected in series, and determines the degree of deterioration of each of the unit cells connected in series. Determining step, a specifying step for specifying a single cell whose deterioration is relatively advanced compared to other single cells by the determining step, and a single cell whose deterioration specified by the specifying step is relatively advanced An exchange step for exchanging.
It is possible to eliminate the non-uniformity of the cells constituting the assembled battery by a simple method and without causing loss.

Moreover, one aspect of the present invention is characterized in that, in the replacement step, a unit cell whose deterioration is relatively advanced is replaced with a new unit cell.
According to such a method, it is possible to reduce the cost for replacement by replacing a unit cell that has been relatively deteriorated with a new unit cell.

Further, according to one aspect of the present invention, in the replacement step, the deterioration is relatively advanced by replacing the unit cell that is relatively deteriorated with another unit cell that is not relatively deteriorated. The arrangement position of the cell is different.
According to such a method, it is possible to further reduce the cost for replacement by changing the arrangement position and uniformizing the deterioration that varies depending on the position.

Further, according to one aspect of the present invention, the determination step determines a plurality of types of deterioration of the unit cell, and the specifying step determines a unit cell to be replaced based on the plurality of types of deterioration by the determination step. It is characterized by specifying.
According to such a method, it is possible to determine deterioration in a multifaceted manner by specifying an exchange target based on a plurality of types of deterioration, and thus it is possible to reliably prevent a load from being concentrated on a specific unit cell. .

Further, according to one aspect of the present invention, the plurality of types of deterioration include at least deterioration due to a temperature of the unit cell, and the specifying step specifies a unit cell whose deterioration is relatively advanced by the temperature, and the replacement The step is characterized in that the unit cell whose deterioration has been relatively advanced by the temperature specified by the specifying means is replaced with a new unit cell or another unit cell whose deterioration has not progressed relatively.
According to such a method, the lifetime of the unit cell can be extended by making the deterioration due to temperature uniform.

Further, according to one aspect of the present invention, in the replacement step, the unit cell that has been deteriorated by the temperature specified by the specifying unit is replaced with another unit cell that has not progressed relatively. Thus, the progression of deterioration due to temperature is made uniform among cells.
According to such a method, the lifetime of the whole assembled battery can be extended by equalizing deterioration due to different temperatures depending on the installation position.

Moreover, one aspect of the present invention is characterized in that the assembled battery is configured by further connecting a plurality of the unit cells connected in series.
According to such a method, it is possible to further extend the life of the assembled battery constituted by a large number of single cells.

One aspect of the present invention is characterized in that the unit cell is a lead acid battery.
According to such a method, the life cycle cost of the assembled battery system using the lead storage battery can be improved by extending the life of the lead battery.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the replacement | exchange method of an assembled battery which eliminates the nonuniformity of the single battery which comprises an assembled battery by a simple method and without producing a loss.

It is a figure which shows the structural example of the storage battery system used as the object to which the assembled battery exchange method which concerns on embodiment of this invention is applied. It is a figure which shows an example of a structural example of the assembled battery shown in FIG. 1, and an example of the deterioration factor of each single cell. It is a figure which shows the aspect of deterioration of the cell which comprises an assembled battery. It is a figure which shows an example of the determination method of deterioration of a cell. It is a figure which shows the progress state of deterioration by the heat from a heat source and a heat source. It is a figure which shows the deterioration state and replacement | exchange method of the cell which comprises an assembled battery. It is an example of the flowchart for demonstrating this invention. It is a figure which shows the structural example of the other storage battery system used as the object to which the assembled battery exchange method which concerns on embodiment of this invention is applied. It is a figure which shows the other structural example of the assembled battery shown in FIG. It is a figure which shows the relationship between the single battery which comprises an assembled battery, and a heat source. It is a figure which shows the relationship between the single battery which comprises an assembled battery, and a heat source. It is a figure which shows the relationship between the single battery which comprises an assembled battery, and a heat source. It is a figure which shows the deterioration factor of the cell shown in FIG. It is a figure which shows the relationship between the single battery which comprises an assembled battery, and a heat source. It is a figure which shows the deterioration factor of the cell shown in FIG. It is a figure which shows the structure row | line | column of the assembled battery connected in parallel. It is a figure which shows the state of deterioration of the assembled battery shown in FIG. It is a figure which shows the state after replacing | exchanging the cell which comprises the assembled battery shown in FIG.

  Next, an embodiment of the present invention will be described.

(A) Description of Application Target of the Present Invention FIG. 1 is a diagram for explaining a configuration example of a power storage system to which a battery pack replacement method according to an embodiment of the present invention is applied. As shown in this figure, the power storage system 20 to which the embodiment of the present invention is applied has a power sensor 21, a power conversion unit 22, an assembled battery 23, a sensor unit 24, and a charge / discharge control device 30, For example, the power from the grid side 10 that is a commercial power supply is supplied to the load 15 arranged in the consumer, and the assembled battery 23 is charged. For example, the power stored in the assembled battery 23 at the peak of power consumption. Is converted into AC power and supplied to the load 15 to execute a peak cut operation.

  Here, the system side 10 indicates a commercial power system operated by an electric power company, and the system side 10 includes, for example, a transformer and a switch.

  The load 15 is, for example, a load of a high-voltage power consumer such as a factory or an office, and is various electric devices that consume power, such as an electric motor, an electric furnace, an air conditioning facility, and an electric lamp. The consumer may be a general household, for example. The load 15 is normally operated by supplying commercial power from the system side 10.

  The power sensor 21 supplies the power supplied from the grid side 10 to the load 15 and the power conversion unit 22, detects the amount of power received (purchased) from the grid side 10, and Supply. As the power sensor 21, not only an analog sensor (power meter) but also a digital sensor (power meter) may be used. In the case of a system that supports power sale, for example, another power sensor for selling power may be provided as the power sensor 21. Furthermore, a smart meter having the function of a gas meter may be used as the power sensor 21.

  The power conversion unit 22 is configured by, for example, a bidirectional inverter. The power conversion unit 22 converts the AC power supplied from the system side 10 through the power sensor 21 into DC power, supplies the battery pack 23 for charging, and supplies the DC power stored in the battery pack 23. It is converted into AC power and supplied to the load 15. In addition to the bidirectional inverter described above, for example, a power converter that combines a DC-DC converter and a DC-AC inverter, a power conditioner, or the like may be used as the power converter 22.

  For example, as shown in FIG. 2A, the assembled battery 23 is configured by connecting a plurality of unit cells 1 to 5 in series. In the example of FIG. 2A, five unit cells are connected in series. However, other than five unit cells (for example, four or less or six units or more) are connected in series. Also good. Further, as will be described later, the cells connected in series may be connected in parallel. In addition, each of the single cells 1 to 5 can store electric power by charging, for example, a lead storage battery, a nickel / cadmium battery, a nickel metal hydride battery, a lithium ion battery, a NAS (sodium / sulfur) battery, and repeatedly used. It is constituted by a battery that can.

  The sensor unit 24 detects, for example, the terminal voltage, charging / discharging current, and environmental temperature (or the temperature of the storage battery itself) of the cells constituting the assembled battery 23 and supplies them to the battery state detection unit 33.

  The charge / discharge control device 30 includes a power consumption detection unit 31, a control calculation unit 32, and a battery state detection unit 33, and the power conversion unit 22 according to the power usage of the load 15 detected by the power sensor 21. The battery pack 23 is charged, and, for example, at the time of peak power consumption, the DC power stored in the battery pack 23 is converted into AC power and supplied to the load 15 to perform peak cut.

  Here, the used power detector 31 detects the used (purchased) power from the system side 10 detected by the power sensor 21 and supplies the detected power to the control calculator 32. As an example, the used power detection unit 31 detects the used power every few minutes and supplies it to the control calculation unit 32. Of course, the unit may be several seconds.

  The battery state detection unit 33 detects the state of the unit cell (for example, SOC (State of State)) based on the terminal voltage, charge / discharge current, and environmental temperature of the unit cell constituting the assembled battery 23 detected by the sensor unit 24. Charge state represented by “Charge”), a state indicating battery characteristics such as charge capacity, chargeable capacity, deterioration degree, or absolute capacity) is detected and notified to the control calculation unit 32.

  The control calculation unit 32 controls the power conversion unit 22 based on the information supplied from the battery state detection unit 33. For example, the control calculation unit 32 charges the assembled battery 23 during the nighttime power period, converts the DC power stored in the assembled battery 23 into the alternating current power mainly during the daytime power peak time period, and supplies it to the load 15. Execute control to By such an operation, part of daytime power is covered by cheap late-night power, and further, the peak of power demand is cut, so that power consumers can reduce the power bill.

(B) Detailed Description of Embodiments of the Invention Next, embodiments of the present invention will be described in detail. In the following, first, the principle of the present invention will be described with reference to FIG. In FIG. 3, the left end is a diagram for explaining the state of the unit cell when the assembled battery 23 is new. In FIG. 3, the numerical values described under the character string “single cell” indicate the deterioration of each single cell in 6 levels from 0 to 5, “0” indicates a new product, and the numerical value is It shows that deterioration is progressing, so that it becomes large. The left end of FIG. 3 shows the case where the assembled battery 23 is new as described above, and the numerical values are all “0”. The center of FIG. 3 is a case where only the unit cell 3 has failed. The value of the unit cell 3 is “3”, and all other units are “0”. In such a case, only the unit cell 3 needs to be replaced. However, as shown in the right end of FIG. 3, when the single cells 1 to 10 are deteriorated due to aging, if only the single cell 6 that is most deteriorated is replaced with a new one, the deterioration of the entire battery is unbalanced. Therefore, the load is concentrated on the unit cell 9 that is being deteriorated next, leading to a failure of the unit cell 9. Therefore, conventionally, in order to avoid such a problem, all of the cells 1 to 10 have been replaced at once.

  On the other hand, in the present embodiment, the degree of deterioration is detected for each unit cell, and a unit cell whose deterioration is relatively more advanced than other unit cells (for example, a unit cell exceeding a predetermined threshold) is to be replaced. For example, replace with a new cell. As a result, as described above, it is possible to effectively use the undegraded unit cells as compared with the case where the entire unit cells connected in series are replaced. In the example at the right end of FIG. 3 described above, by replacing both the unit cell 6 and the unit cell 9 with another unit cell (for example, a new unit cell or a used unit cell) having a deterioration level of 2 or less. Since the deterioration degree of the single cells connected in series can be within the range of 1 to 2, it is possible to avoid the concentration of the load on the specific single cells.

  As a method for detecting the degree of deterioration, for example, as shown in FIG. 4, when the assembled battery 23 is discharged with a constant discharge current, the discharge voltage (terminal voltage) is a predetermined voltage (for example, FIG. 4). In the example, the time to reach 10.5V) is measured, and deterioration can be detected by the length of the time. In the example of FIG. 4, it can be determined that the deterioration progresses in the order of a solid line, a short broken line, a long broken line, and a one-dot chain line.

  Further, in the present embodiment, a plurality of deterioration factors can be detected as the deterioration factor of the unit cell, and the unit cell to be replaced can be specified based on the plurality of deterioration factors. FIG. 2B shows an example of the deterioration factor. In this example, the unit cell to be replaced is specified based on the three types of deterioration factors A to C. Here, the deterioration factor A is, for example, a factor that affects the storage life. For example, the cross-sectional area decreases due to corrosion of the positive electrode lattice and the internal resistance increases, or the bonding with the active material is impaired due to the elongation of the lattice. It is a deterioration factor. Such positive electrode lattice corrosion is caused by, for example, an increase in environmental temperature. Further, the degradation factor B is a factor that affects the cycle life, for example, and is caused by the sparseness of the active material. Further, the deterioration factor C is a factor generated by, for example, a short circuit of the electrode plate.

  Here, in the case of the degradation factor A, as described above, the progress of degradation changes depending on the storage temperature. For this reason, as shown in FIG. 5, when a heating element such as an engine is arranged near the assembled battery 23, the deterioration of the unit cell closer to the heating element is faster than the unit cell farther away. To do. Thereby, the deterioration of the unit cell is biased. Of course, factors other than the storage temperature (for example, vibration, etc.) are also affected, and the influences of each unit cell are not uniform. For example, in FIG. 2B, with regard to the deterioration factor A, the single cell 3 is most deteriorated at the deterioration degree 3, but the deterioration factors B are all the same at the deterioration degree 2, and the deterioration factor C is simply The batteries 2 and 4 are deteriorated at a deterioration degree of 4.

  For example, as in the example of FIG. 6A, when the degradation factor C is, the unit cell 2 and the unit cell 4 have a degradation level of 4, and the others have a degradation level of 0, only the unit cell 2 and the unit cell 4 are replaced. When they are exchanged, as shown in FIG. 6B, all the deterioration factors C have a degree of deterioration of 0, and there is no problem. However, with regard to the degradation factor A, the unit cell 3 has a degradation degree of 5, which is a problem. Therefore, in the present embodiment, the cells 2, 3, and 4 in which the deterioration factors A to C correspond to the deterioration degree 4 or higher are set as replacement targets. Thereby, the deterioration of the unit cell can be determined from multiple aspects by determining the plurality of deterioration factors. As a result, it is possible to prevent the load from being concentrated on a specific unit cell and immediately replacing it even though the unit cell is replaced.

  Next, a flow of a method according to the present embodiment will be described with reference to FIG. In the example shown in FIG. 7, the following steps are executed. Hereinafter, a case where the control calculation unit 32 executes the process will be described as an example.

In step S10, the control calculation unit 32 controls the battery state detection unit 33 to detect the state of the unit cell. For example, the control calculation unit 32 detects the state of each unit cell constituting the assembled battery 23 based on the output of the sensor unit 24. As a method for detecting the state, for example, the internal impedance of the cell constituting the assembled battery 23 is measured, and the SOC is calculated based on the corrected impedance value obtained by correcting the impedance value with temperature. Alternatively, it can be calculated based on OCV (Open Circuit Voltage). In addition, in a series of reaction processes called electrochemical reactions inside the battery, not only the ion formation and extinction reaction (fast reaction rate) occurring in the vicinity of the electrode plate, but also the ion diffusion rate (slow reaction rate) in the electrolyte solution is the reaction process. In such a reaction system, reaction processes having different velocities have a great influence on the state detection of SOC or the like as an error factor. Therefore, as described in Japanese Patent No. 4702859, the voltage Vmes, current Imes, and temperature Tmes of the storage battery are measured, and it is determined whether or not the absolute value of the measured current Imes is smaller than the current value threshold value Ithre, and stable OCV estimation is performed. ^SOC n-1 after the previous charging and discharging based on the formula to estimate the _{OCV 20 hr} from ^{SOH n-1,} and stored by calculating the difference between the voltage measurement value Vmes and _{OCV 20 hr,} relaxed depending on the time t By updating the function F ⁿ (t), calculating the SOH ⁿ using the updated F ⁿ (t), and calculating the SOC ⁿ , the SOC can be accurately calculated in consideration of deterioration due to the reaction process with different speeds. Can be detected. Of course, other methods may be used.

  In step S11, the control calculation unit 32 detects the deterioration factor A. For example, the deterioration factor A is obtained based on the deterioration factor that affects the storage life of the deterioration calculated in step S10.

  In step S12, the control calculation unit 32 detects the deterioration factor B. For example, the deterioration factor B is obtained based on the deterioration factor that affects the cycle life of the deterioration calculated in step S10.

  In step S13, the control calculation unit 32 detects the deterioration factor C. For example, the degradation factor C is obtained based on a failure factor such as a short circuit among the degradations calculated in step S10.

  In step S14, the control calculation part 32 performs deterioration determination about the deterioration factor C (deterioration factor with the highest priority) of each cell detected in step S13. As a method for determining deterioration, for example, when the degree of deterioration is a predetermined threshold or more (for example, 4 or more), it can be determined that the deterioration has occurred. In this process, when the deterioration is recognized, the determination result may be notified immediately.

  In step S15, the control calculation unit 32 performs the deterioration determination for the deterioration factor A (the deterioration factor having the second highest priority) of each single cell detected in step S11. As a method for determining deterioration, for example, when the degree of deterioration is a predetermined threshold or more (for example, 4 or more), it can be determined that the deterioration has occurred. In this process, when the deterioration is recognized, the determination result may be notified immediately.

  In step S16, the control calculation part 32 performs deterioration determination about the deterioration factor B (deterioration factor with the lowest priority) of each single cell detected in step S12. As a method for determining deterioration, for example, when the degree of deterioration is a predetermined threshold or more (for example, 4 or more), it can be determined that the deterioration has occurred.

  In step S17, the control calculation unit 32 notifies the determination result to an ECU (Electronic Control Unit) (not shown). And the replacement | exchange operation | work of the cell which comprises an assembled battery is implemented as needed.

  According to the above process, it is possible to individually detect the deterioration of the single cells connected in series, and to specify the single battery in which the deterioration is relatively advanced. Further, since the determination is made for a plurality of deterioration factors, it is possible to detect the deterioration of the single cell from various aspects. Furthermore, since priority is given to degradation factors, if degradation with high priority is found, notification is made immediately, or it is judged that degradation has occurred without making decisions regarding other degradation factors. By doing so, the processing can be shortened.

(G) Modified Embodiment Each of the above embodiments is an example, and there are various modified embodiments other than this. For example, in the embodiment shown in FIG. 1, the result of the deterioration determination is notified to the ECU. For example, as shown in FIG. 8, a display unit 34 connected to the control calculation unit 32 is provided, and the control calculation unit The result of the deterioration determination determined by 32 may be displayed to indicate the unit cell to be replaced. In addition, as information to be displayed, information (for example, a serial number registered in advance) that can identify a unit cell to be replaced can be displayed. Further, the battery state detection unit 33, the control calculation unit 32, and the display unit 34 may be incorporated into the assembled battery 23 itself, or may be incorporated into each single battery.

  Moreover, in the above embodiment, the case where one set of unit cells connected in series was used as the assembled battery 23 was described as an example. For example, as shown in FIG. 9, a group of unit cells connected in series May be connected in parallel. In the example of FIG. 9, the single cells 1 to 5 connected in series, the single cells 6 to 10 connected in series, and the single cells 11 to 15 connected in series are switches 50-1 to 50-3. Are connected in parallel. The on / off states of the switches 50-1 to 50-3 are controlled by the control arithmetic unit 32. In the case of such a configuration, the control arithmetic unit 32 turns on / off the switches 50-1 to 50-3, thereby selecting a unit cell group to be detected, and for the selected unit cell group. Thus, by executing the processing shown in FIG. 7, it is possible to determine whether or not the unit cell needs to be replaced.

  Further, in the above embodiment, the deterioration factor is detected, and the unit cell to be replaced is replaced based on the detection result. For example, as shown in FIG. When present in the vicinity of the battery, as the deterioration factor A related to the storage temperature is closer to the heat source as shown in FIG. In the example of FIG. 10, the unit cells 3 and 4 close to the heat source have a relatively large deterioration factor A as compared to other unit cells. Therefore, when an increase in the degradation factor A is detected, as shown in FIG. 11A, the single cells that have been disposed near the heat source and have increased the degradation factor A are disposed far from the heat source. The deterioration factor A can be made uniform by disposing the single cells, which have been disposed far away, near the heat source. Accordingly, as shown in FIG. 11B, the single cells 5 and 1 having a small value of the degradation factor A are arranged near the heat source, and the single cells 3 and 4 having a large value are arranged at a location far from the heat source. Thus, deterioration can be made uniform.

  Further, in the examples of FIGS. 10 and 11, the case where one set of unit cells connected in series is used has been described. However, for example, as shown in FIG. 12, when a plurality of sets of unit cells connected in series are used. The present invention can be applied. In the example of FIG. 12, the single cells 1 to 5, the single cells 6 to 10, and the single cells 11 to 15 connected in series are connected in parallel. Further, a heat source is disposed in the vicinity of the unit cell 10. FIG. 13 shows a deterioration state of each unit cell shown in FIG. In the example of FIG. 12, since the heat dissipated from the heat source rises by warming the surrounding air, the value of the deterioration factor A of the cells 6 to 10 existing immediately above the heat source increases and warm air is stored. The deterioration factor A of the upper cells 1 and 11 is increased. In such a case, as shown in FIG. 14 and FIG. 15, the cells 5 to 10 located immediately above the heat source are arranged at a position away from the heat source and arranged at the upper part where warm air is stored. The unit cells 1 and 11 are also rearranged at positions far from the heat source. In this way, by changing the arrangement with reference to the heat source, it is possible to extend the life of the entire assembled battery by making the deterioration due to heat uniform.

  Further, in the above embodiment, the rearrangement is performed on the basis of being away from the heat source. However, for example, the rearrangement is performed on the basis that the deterioration of the group of unit cells connected in series is almost the same. It may be. In the example of FIG. 16, ten unit cells 1 to 10, 11 to 20, 21 to 30, and 31 to 40 are connected in series, and a group of unit cells connected in series are connected in parallel. In FIG. 16, since all the cells are in a new state, the numerical values displayed under the character string “cell” are all “0”. FIG. 17 shows a state in which the deterioration has progressed. In this example, since the heat is not deteriorated by the heat source, the unit cell has no regularity and has been deteriorated. FIG. 18 is a diagram showing a state where the cells shown in FIG. 17 are rearranged according to the degree of deterioration. In FIG. 18, new unit cells 51 to 60 having a degradation degree of “0” are added to the leftmost column. Further, in the second column from the left, single cells having degradation levels of “1” and “2” are arranged. More specifically, the unit cell 19 having a deterioration degree “1” and the unit cells 1, 4, 7, 11, 14, 17, 21, 24 having a degree of deterioration “2” are arranged. Further, in the third column from the left, single cells having deterioration degrees “2” and “3” are arranged. Specifically, the single cells 27, 31, 34, and 37 having a degradation level of “2” and the single cells 2, 3, 5, 8, 10, and 12 having a degradation level of “3” are arranged. In addition, at the right end, a single cell having a degradation degree of “3” is arranged. Specifically, the single cells 13, 18, 20, 22, 25, 28, 29, 30, 32, and 33 having the deterioration degree “3” are arranged. Note that the cells 6, 23, and 26 with the deterioration degree “5” and the battery cells 9, 15, and 39 with the deterioration degree “4” are excluded. In addition, the single cells 35, 36, 38, and 40 having a degree of deterioration of “3” are redundant, and are also excluded. As described above, by combining the unit cells having substantially the same degree of deterioration and connecting them in series, it is possible to prevent the load from being concentrated on the unit cells that have deteriorated and the deterioration from proceeding.

  In the above embodiment, the battery state is detected by providing the sensor unit 24 and the battery state detection unit 33. However, for example, these may be equipped as necessary or possible. It may be configured as a portable inspection device to detect the state of the unit cell.

  Further, the deterioration factors A to C described above are examples, and other factors may be used, or at least one of these deterioration factors A to C may be used. Further, instead of evaluating the degree of deterioration in 6 stages of 0 to 5, it may be evaluated in 10 stages, evaluated by continuous values, or may be evaluated in different stages for each deterioration factor. Although the determination of deterioration is made by comparing with a threshold value, evaluation may be performed based on a value obtained by multiplying each deterioration factor by a weighting coefficient and adding the obtained values. .

  In the above embodiment, the type of the assembled battery 23 is not mentioned, but the progress of deterioration changes depending on the type of the assembled battery 23. For example, the determination control is changed depending on the type of the assembled battery 23. It may be. Such a setting may be set according to the type of the assembled battery 23, for example.

  Further, in the above embodiment, the case where the present invention is applied to the power storage system has been described as an example. However, in addition to this, for example, in an assembled battery mounted on a moving body such as a vehicle, a ship, and an aircraft The present invention can be applied.

  Further, the flowchart shown in FIG. 7 is an example, and the determination may be made based on other flowcharts.

DESCRIPTION OF SYMBOLS 10 System side 15 Load 20 Power storage system 21 Electric power sensor 22 Electric power conversion part 23 Battery assembly 24 Sensor part 30 Charging / discharging control apparatus 31 Used electric power detection part 32 Control calculating part (control means)
33 Battery state detector

Claims (8)

In the replacement method of the assembled battery configured by connecting secondary batteries as a plurality of unit cells in series,
A determination step of determining the degree of deterioration of each of the cells connected in series;
The determination step specifies a single cell whose deterioration is relatively advanced than other single cells, and
A replacement step of replacing the unit cell in which the deterioration specified in the specifying step is relatively advanced;
A method for replacing an assembled battery, comprising:   The method for replacing an assembled battery according to claim 1, wherein the replacing step replaces the unit cell that is relatively deteriorated with a new unit cell.   In the replacement step, the position of the unit cell that is relatively deteriorated is changed by replacing the unit cell that is relatively deteriorated with another unit cell that is not relatively advanced. The method for replacing an assembled battery according to claim 1, wherein: The determination step determines a plurality of types of deterioration of the unit cell,
The specifying step specifies a unit cell to be replaced based on a plurality of types of deterioration in the determination step.
The method for replacing an assembled battery according to any one of claims 1 to 3. The plurality of types of deterioration include at least deterioration due to the temperature of the unit cell,
In the identifying step, a cell that has been relatively deteriorated by temperature is identified,
The replacement step replaces the unit cell whose deterioration has been relatively advanced by the temperature specified by the specifying means with a new unit cell or another unit cell whose deterioration has not progressed relatively,
The method for replacing an assembled battery according to any one of claims 1 to 4, wherein:   In the replacement step, the progress of deterioration due to temperature is simply changed by replacing a unit cell whose deterioration has been assumed by the temperature specified by the specifying means with another unit cell whose deterioration has not progressed relatively. The method for replacing an assembled battery according to claim 5, wherein the batteries are made uniform among the batteries.   The assembled battery replacement method according to any one of claims 1 to 6, wherein the assembled battery is configured by further connecting a plurality of the single cells connected in series.   The method for replacing an assembled battery according to claim 1, wherein the unit cell is a lead storage battery.

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