Battery degradation management system

Abstract

The purpose of the present invention is to provide a technology with which it is possible to appropriately select an economically highly effective measure and the implementation timing thereof as a measure to be implemented when a secondary battery has deteriorated. A battery deterioration degree management system according to the present invention calculates the costs required to implement measures for reducing the deterioration state of a battery, on the basis of cost data describing costs associated with the implementation of the measures, and determines an economically highly effective measure and the implementation timing thereof on the basis of the calculated costs (see Fig. 4).

Description

TECHNICAL FIELD

[0001] The present invention relates to a technique for managing the degree of battery deterioration. BACKGROUND ART

[0002] Secondary batteries gradually deteriorate with use, and when the deterioration reaches a certain level, some measure needs to be taken. Examples of the measures referred to herein include (a) rebalancing that equalizes the state of charge of each battery constituting a battery group, (b) rebuilding that regenerates a highly deteriorated battery (reconstructs it as a regenerated product), and (c) repurposing for other applications.

[0003] Patent Document 1 addresses the problem of "providing a system that can reduce the transportation cost of used secondary batteries and sell the used secondary batteries at low cost", and describes a technology of "the used secondary battery reuse system of the present invention supports the reuse of used secondary batteries that have been used as secondary batteries for driving vehicles. The system includes a purchase request information receiving unit that receives purchase request information for used secondary batteries, a trade-in request information receiving unit that receives trade-in request information including information indicating the deterioration state of the secondary batteries mounted on vehicles, an extraction unit that extracts purchase request information in which the use of the used secondary batteries matches the deterioration state included in the trade-in request information, a sales price determination unit that determines the sales price of the secondary batteries to be traded in, a transportation cost estimation unit that estimates the transportation cost from each trade-in facility of the secondary batteries to be traded in to the delivery location, and a trade-in price determination unit that determines the trade-in price at each trade-in facility based on the sales price and the transportation cost of the secondary batteries to be traded in." (see the abstract).

[0004] Patent Document 2 describes a method for calculating the battery capacity of a battery pack as a technology related to the present invention. The application describes a method for diagnosing a battery pack using a system that obtains detection data including the current and temperature of a battery pack having a configuration in which multiple cells are connected in series, and the voltage of each cell, comprising the steps of: calculating the charge capacity and SOC of each cell using the current and temperature, the voltage of each cell, the SOC function of the OCV and a resistance table, and calculating the unbalance amount and resistance, which are estimated values ​​of the SOC of each cell when the battery pack is fully charged; and calculating the energy capacity of the battery pack using the charge capacity, unbalance amount and resistance. This makes it possible to accurately calculate the energy capacity of the battery pack even in an unbalanced state. (See abstract) [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-124982 [Patent Document 2] WO2022 / 024885A1 [Overview of the project] [Problems that the invention aims to solve]

[0006] Conventional technologies, such as those described in Patent Document 1, aim to reduce the costs associated with reusing used batteries. However, the costs incurred when reusing degraded secondary batteries include costs that fluctuate over time, so it is desirable to consider such dynamically fluctuating costs. Furthermore, when deciding what measures to implement, it is desirable to consider the impact of costs that fluctuate over time and select measures that have a high economic effect and the timing of their implementation. The same applies when implementing measures other than reuse. Conventional technologies do not adequately consider such costs that fluctuate over time, so there is a possibility that measures that do not necessarily have a high economic effect may be implemented, or that measures may be implemented at a time that does not necessarily have a high economic effect.

[0007] This invention has been made in view of the above-mentioned problems, and aims to provide a technology that allows for the appropriate selection of economically effective measures and their timing as measures to be implemented when a secondary battery deteriorates. [Means for solving the problem]

[0008] The battery degradation management system according to the present invention calculates the costs necessary to implement measures to address the deterioration of a battery, based on cost data describing the costs associated with such measures, and determines the most economically effective measures and the timing of their implementation based on those costs. [Effects of the Invention]

[0009] According to the battery degradation management system of the present invention, when a secondary battery degrades, it is possible to appropriately select economically effective measures and the timing of their implementation. Other issues, configurations, and effects of the present invention will become clear from the following description of embodiments. [Brief explanation of the drawing]

[0010] [Figure 1] This is a diagram showing the configuration of the battery degradation management system 1 according to Embodiment 1. [Figure 2] This is a schematic diagram showing the processing flow performed by the arithmetic unit 11. [Figure 3] The results of predicting the time-dependent change in the State of Health (SOH) of battery cells are shown. [Figure 4] This is a schematic diagram showing the processing flow performed by the arithmetic unit 11. [Figure 5] This figure shows the results of measuring the State of Health (SOH) for each battery cell. [Modes for carrying out the invention]

[0011] <Embodiment 1> Figure 1 is a diagram showing the configuration of a battery degradation management system 1 according to Embodiment 1 of the present invention. The battery degradation management system 1 is a system for managing the state of health (SOH) of a secondary battery (hereinafter simply referred to as a battery). The battery degradation management system 1 comprises a calculation unit 11 and a storage unit 12.

[0012] The calculation unit 11 receives characteristic data and measurement data and uses them to estimate the State of Health (SOH) of the battery. Any known technique can be used for the estimation procedure. The calculation unit 11 further identifies batteries that are deteriorating based on the estimated SOH and determines measures to be taken for those batteries. When determining measures, efforts are made to optimize the economic effect of the measures. Specific examples of measures and the procedure for determining them will be described later. The storage unit 12 stores the data used by the calculation unit 11.

[0013] Characteristic data describes the physical characteristics of the battery and can be obtained in advance before estimating the State of Health (SOH). Characteristic data describes the SOC-OCV curve, SOC-charging resistance curve, SOC-discharge resistance curve, number of battery cells, rated capacity (Wh), etc. The SOC-OCV curve is calculated between the battery's SOC (State of Charge) and OCV (Open Circuit Voltage). The SOC-charging resistance curve is calculated between the battery's SOC and charging resistance. The SOC-discharge resistance curve is calculated between the battery's SOC and discharge resistance. The number of battery cells is the number of cells that make up the battery. The rated capacity (Wh) is the rated capacity of the battery.

[0014] Measurement data describes the results of measuring the physical state of a battery and can be obtained, for example, from a battery management unit (BMU). Measurement data includes a timestamp, battery current, battery voltage, battery temperature, etc. The timestamp is the date and time the measurement data was acquired (or the date and time the measurement was performed). Battery current, battery voltage, and battery temperature are the battery's output current, battery's output voltage, and battery temperature (or the temperature of the ambient environment around the battery), respectively.

[0015] Figure 2 is a schematic diagram showing the processing flow executed by the arithmetic unit 11. The arithmetic unit 11 estimates the SOH of the battery using the characteristic data and the measurement data. Specifically, the battery capacity can be calculated using the integrated value of the current value during charging, and the SOC of the battery at the start of charging and at the end of charging. Further, the SOH can be estimated based on the formula "SOH = 100 × battery capacity / rated capacity of the battery". Alternatively, any known technique such as that disclosed in Patent Document 2 can be used. As another method, for example, a temporal change in battery voltage during a rest period after a charging operation or a discharging operation is acquired, and the SOH can be estimated based on the correspondence between the temporal change and the SOH.

[0016] The arithmetic unit 11 predicts the temporal change of the SOH. Since the SOH gradually decreases with the passage of time, the future temporal change of the SOH can be predicted based on, for example, the time decrease rate thereof. The prediction may be performed using any other arbitrary method. The prediction of the future temporal change of the SOH may be performed by linear approximation, approximation by ARMA (AutoRegressive Moving Average) or Weibull distribution, or any other arbitrary method may be used for the prediction.

[0017] The arithmetic unit 11 identifies a battery with a lowered SOH, and further determines a measure to be implemented for that battery. Examples of the measure to be implemented include (a) rebalancing for equalizing the state of charge of each battery constituting the battery group, (b) rebuilding for regenerating (reconstructing as a regenerated product) a battery with significant degradation, and (c) repurposing for other applications.

[0018] A battery cell that has progressed in degradation has, for example, a larger decrease in SOC during discharge than other battery cells. Rebalancing is a process of equalizing the SOC between a battery cell that has progressed in degradation and a battery cell that has not progressed in degradation. As a result, the entire battery group can exhibit performance close to the rated capacity. In this respect, rebalancing is suitable as a measure to be implemented for a battery cell that has progressed in degradation.

[0019] When the deterioration of battery cells progresses beyond the extent where performance can be recovered by rebalancing, measures other than rebalancing are required. Rebuilding is selected as a measure for such battery cells. Specifically, deteriorated battery cells are removed from the battery group and reconstructed as regenerated products. More simply, the deteriorated battery cells may be replaced with new batteries. In the present embodiment, this is also regarded as rebuilding in a broad sense.

[0020] From a perspective different from the battery cells, measures can also be implemented for the entire battery group. For example, when the SOH of the entire battery group gradually deteriorates, the battery group may still be usable but fail to meet the performance requirements in the current usage environment. In such a case, it is conceivable to divert the battery group to another usage environment with more lenient performance requirement demands. Conversely, when the SOH of the entire battery group is sufficiently high, it is conceivable to divert the battery group to another usage environment with more stringent performance requirement demands. The battery group referred to herein may be a battery module composed of a plurality of battery cells, a battery pack composed of a plurality of battery modules, or any other arbitrary unit.

[0021] Diverting a battery also includes recycling by disassembling the battery to extract materials. Therefore, the application of the diversion destination shall include recycling applications, and these are collectively handled as "diversion" in a broad sense that encompasses them.

[0022] The calculation unit 11 aims to optimize the economic effect of the measure when selecting the measure to be implemented on the deteriorated battery. Thereby, the battery on which the measure is to be implemented is determined, and the content and implementation timing of the measure are optimized from the perspective of economic effect. The specific optimization method will be described later.

[0023] Figure 3 shows the results of predicting the change in the State of Health (SOH) of a battery cell over time. When the degradation of SOH is relatively small (SOH is above the first threshold), rebalancing can be selected as a countermeasure. When the degradation of SOH progresses further (SOH is below the first threshold but above the second threshold), rebuilding can be selected as a countermeasure. On the vertical axis of Figure 3, the intervals for selecting rebalancing and the intervals for selecting rebuilding may or may not be adjacent. If the two intervals are not adjacent, the countermeasure implemented in the gap between the two intervals may be either rebalancing or rebuilding.

[0024] The calculation unit 11 can choose whether to perform rebalancing or rebuilding according to Figure 3, or alternatively, it can choose a measure that optimizes economic effects. For example, if diversion is used as a measure option, the economic effects of diversion can be compared with the economic effects of other measures. Alternatively, for batteries with SOH near the boundary between rebalancing and rebuilding in Figure 3, either rebalancing or rebuilding may be adopted, so the economic effects can be taken into account to select which measure to adopt. Below, a method that considers economic effects instead of the method in Figure 3 will be described.

[0025] Figure 4 is a schematic diagram showing the processing flow performed by the calculation unit 11. Figure 4 shows a specific example of the optimization process in Figure 2. The calculation unit 11 receives cost data and price data and uses them to optimize (a) the target batteries for which measures will be implemented, and (b) the content of the measures and the timing of their implementation.

[0026] Cost data describes the costs incurred as a result of implementing a policy, as well as the predicted changes in those costs over time. Cost data includes personnel costs, equipment costs, etc. Personnel costs are those that fluctuate over time as a result of implementing a policy, and are defined for each policy. Equipment costs are those that fluctuate over time as a result of implementing a policy, and are defined for each policy. If the fluctuation of costs over time is small, fluctuation forecasting is not necessarily required. In this case, all costs are considered constant over time. The same applies to price data, which will be discussed later.

[0027] The price data describes the predicted results of battery prices and their fluctuations over time. The price data includes used battery prices, battery material prices, and new battery prices. Used battery prices are the market prices for used batteries. Battery material prices are the market selling prices of materials used when recycling batteries. New battery prices are the market prices for new batteries.

[0028] The calculation unit 11 uses cost data and price data to estimate the economic effects of the measures. For example, it calculates the economic effect of performing a rebalancing on a certain battery cell at that time, based on the cost data and price data. Furthermore, it calculates the economic effect of performing a rebuild on that battery at that time, based on the cost data and price data. Furthermore, it calculates the economic effect of repurposing that battery at that time, based on the cost data and price data.

[0029] The economic effect of rebalancing is determined by factors such as the costs incurred in performing the rebalancing and the increased economic value of the battery due to the extended battery life resulting from the rebalancing. The costs can be calculated from cost data. The increased economic value can be evaluated using an arbitrary evaluation function based on the increase in battery life and the temporal fluctuations in battery prices.

[0030] The economic effect of rebuilding is determined by factors such as the costs incurred in carrying out the rebuild and the increased economic value of the battery due to the extended battery life resulting from the rebuild. Costs can be calculated from cost data and price data. Specifically, the cost required to replace degraded cells with new or used ones is calculated by referring to the price of used or new batteries. The increased economic value can be evaluated using an arbitrary evaluation function based on the increase in battery life and the change in battery price over time.

[0031] The economic effect of repurposing is determined by factors such as the costs incurred in carrying out the repurposing and the profits obtained from it. Profits can be calculated based on price data, for example, when selling to another business. Costs (including labor and transportation costs required for the sale) can be calculated from cost data. When repurposing within the business itself, the economic effect is determined by the cost required to dispose of existing batteries at the repurposed location and the increased economic value of the batteries due to the extended battery life (the extended period of use due to the repurposed batteries) at the repurposed location.

[0032] The calculation unit 11 estimates the economic effects of each measure for each implementation period. Based on the results, the calculation unit 11 optimizes the measures to be implemented and their implementation timing. For example, for a certain battery, the calculation unit 11 compares (a) the economic effects of immediately repurposing it, (b) the economic effects of continuing to use it until the end of its lifespan through rebalancing or rebuilding, and (c) the economic effects of repurposing it after continuing to use it until a certain point through rebalancing or rebuilding, to determine the measures and implementation timing that will have the greatest economic effect.

[0033] <Embodiment 1: Summary> The battery degradation management system 1 according to this embodiment 1 optimizes the measures to be taken in response to the decrease in the battery's State of Health (SOH) and the timing of their implementation, based on costs that fluctuate over time. This makes it possible to optimize the economic effectiveness of the measures taken in response to battery degradation from a cost perspective.

[0034] The battery degradation management system 1 according to this embodiment 1 optimizes the measures to be taken and the timing of their implementation in response to the decrease in the battery's State of Health (SOH), based on the time-varying costs and battery market prices. This makes it possible to optimize the economic effects of the measures taken in response to battery degradation from the perspective of market price and cost. Although both market price and cost fluctuate over time, according to this embodiment 1, by considering the time-varying changes in both market price and cost for each of the multiple measures, it is possible to select the optimal measure while taking these fluctuating prices into account.

[0035] <Embodiment 2> In Embodiment 1, we described selecting whether to perform rebalancing or rebuilding according to Figure 3, or selecting measures to optimize economic effects. In Embodiment 2 of the present invention, we will describe an alternative method for selecting measures. The configuration of the battery degradation management system 1 is the same as in Embodiment 1.

[0036] The calculation unit 11 first calculates the amount of State of Health (SOH) that can be recovered by performing rebalancing for each battery cell. The calculation unit 11 calculates the economic effect of performing rebalancing for each battery cell using the method described in Embodiment 1. For battery cells where the economic effect is sufficient (an economic effect above the threshold is expected), rebalancing is selected as the measure. Otherwise, the procedure proceeds to the following step. The battery cells targeted in this step may be limited to those whose SOH will be significantly recovered by rebalancing (the amount of increase in SOH is above the threshold).

[0037] Figure 5 shows the results of measuring the State of Health (SOH) for each battery cell. The calculation unit 11 determines whether the SOH of the battery cells for which rebalancing was not selected is below a threshold. In Figure 5, there is one battery cell whose SOH is below the threshold. The calculation unit 11 calculates the economic effect of rebuilding this battery cell using the method described in Embodiment 1. If the economic effect is sufficient (an economic effect exceeding the threshold is expected), rebuilding is selected as the measure for this battery. Otherwise, repurposing is selected as the measure for this battery.

[0038] The method described in Embodiment 1 estimates the economic effects of all measures for each implementation period, allowing for the optimization of measures and their implementation timing, but it has a heavy computational load. The method in Embodiment 2 prioritizes measures in the order of rebalancing => rebuilding => repurposing, thus reducing the computational load compared to Embodiment 1.

[0039] The calculation unit 11 may consider environmental impact as a preliminary consideration when selecting a policy. For example, it is conceivable to acquire environmental impact data in advance, which describes indicators representing the environmental impact that will occur as a result of implementing the policy, and then adjust the economic effect of the policy according to the indicators described in that data. The calculation unit 11 then selects a policy according to the adjusted economic effect.

[0040] <Embodiment 3> Embodiment 3 of the present invention describes a method for estimating the SOH of a battery. The configuration of the battery degradation management system 1 is the same as in Embodiments 1 and 2.

[0041] Patent Document 2 describes a method for determining a function that indicates the degradation of a battery pack based on its battery capacity, and for estimating the rate of degradation and the replacement timing using this function. Since the rate of degradation corresponds to the State of Health (SOH), this method can be used to estimate the SOH of the battery. This method estimates the degradation state of the battery based on the change in SOC over time.

[0042] Specifically, first, the measured values ​​of battery voltage, battery current, and battery temperature are obtained. Furthermore, the SOC-OCV curve and the SOC-charging resistance curve are referenced. SOC can be calculated by integrating the battery current over time. Since charging resistance has a temperature characteristic, the charging resistance can be obtained by referencing the SOC-charging resistance curve using SOC and battery temperature. The relationship between OCV and SOC can be obtained from the SOC-OCV curve. The relationship between battery voltage and OCV can be calculated from charging resistance and battery current. Convergence calculations are performed until the difference between the calculated battery voltage and the measured value becomes sufficiently small. Furthermore, the discharge resistance is obtained by referencing the SOC-discharge resistance curve, and the SOC at the time discharge stops is determined using this discharge resistance. Based on the difference between the SOC after charging and the SOC after discharge, the battery capacity can be determined. Furthermore, an approximate function representing the degradation rate is obtained based on the time-series change in capacity. This is because the battery capacity gradually decreases as the battery degradation progresses. The calculation unit 11 can estimate SOH using this method.

[0043] The calculation unit 11 can also estimate the State of Health (SOH) based on the measurement results of the battery output, either as an alternative to or in combination with the method described in Patent Document 2. For example, the method described in WO2022 / 024235A1 can be used. In that document, the fluctuation in battery voltage during the rest period after a charging or discharging operation is obtained and used to estimate the SOH. For example, the relatively steep voltage fluctuation (first difference) in the period immediately after stopping charging and discharging correlates with the internal resistance of the battery, and the relatively gradual voltage fluctuation (second difference) in the subsequent period correlates with the SOH of the battery.

[0044] Therefore, in the same document, first data describing the relationship between the first difference and internal resistance, and second data describing the relationship between the second difference and SOH are acquired in advance, and the internal resistance and SOH are estimated by referring to these data using the measured values ​​of the first difference and the second difference, respectively. This method can estimate SOH in a relatively short time. The calculation unit 11 can estimate SOH using this method.

[0045] <Regarding variations of the present invention> The present invention is not limited to the embodiments described above, and includes various modifications. For example, the embodiments described above are described in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations.

[0046] In the embodiments described above, the arithmetic unit 11 can be configured by hardware such as a circuit device that implements its function, or by a computing device such as a CPU (Central Processing Unit) executing software that implements its function.

[0047] In the embodiments described above, an example of implementing measures for each battery cell was explained, but the target of implementing measures is not limited to individual cells. For example, measures may be implemented for each battery module composed of multiple battery cells, or for each battery pack composed of multiple battery modules. A combination of these is also acceptable.

[0048] In the embodiments described above, the following are possible, but are not limited to, the cost items or benefit items used when calculating the economic effects of the measures: • Reduced asset maintenance costs: The frequency of periodic repairs and replacements decreases, reducing maintenance costs. • Reduced investment: The time between purchasing similar assets is extended, reducing the amount of investment required. • Improved cash flow: By reducing investment and maintenance costs, cash flow improves, securing funds that can help stabilize the business and drive future growth. • Increased selling price: By implementing measures to reduce deterioration, the selling price will increase. [Explanation of Symbols]

[0049] 1: Battery degradation management system 11: Arithmetic section 12: Storage part

Claims

1. A calculation unit that estimates the degradation state of multiple batteries. A storage unit that stores the data used by the aforementioned calculation unit, Equipped with, The calculation unit identifies among the plurality of batteries that require measures to be taken to address the deterioration of the state, The calculation unit calculates the costs necessary to implement the measures based on cost data that describes at least one of the changes in costs over time or predictions of costs associated with implementing the measures, Based on the calculated costs, the calculation unit determines which of the multiple measures can maximize economic effect and the timing of its implementation. The aforementioned measures are, Rebalancing to equalize the charge state of the aforementioned multiple batteries, Rebuilding the aforementioned battery, The aforementioned battery can be repurposed for other applications with different performance requirements. At least one of the following: The calculation unit selects the rebalancing as the measure if the deterioration state is equal to or greater than the first threshold. The calculation unit selects the rebuild as the measure if the degradation state is greater than or equal to the second threshold and less than or equal to the first threshold. A battery degradation management system characterized by the following features.

2. A calculation unit that estimates the degradation state of multiple batteries. A storage unit that stores the data used by the aforementioned calculation unit, Equipped with, The calculation unit identifies among the plurality of batteries that require measures to be taken to address the deterioration of the state, The calculation unit calculates the costs necessary to implement the measures based on cost data that describes at least one of the changes in costs over time or predictions of costs associated with implementing the measures, Based on the calculated costs, the calculation unit determines which of the multiple measures can maximize economic effect and the timing of its implementation. The aforementioned measures are, Rebalancing to equalize the charge state of the aforementioned multiple batteries, Rebuilding the aforementioned battery, The aforementioned battery can be repurposed for other applications with different performance requirements. At least one of the following: If the degradation state of the entire group of batteries is above the third threshold, the calculation unit selects, as a measure, to repurpose the batteries for other applications that have higher performance requirements than the current operating environment of the batteries. If the overall degradation state of the multiple batteries is below the fourth threshold (which is less than the third threshold), the calculation unit selects, as a measure, to repurpose the multiple batteries for other uses where the performance requirements are lower than those of the current operating environment. A battery degradation management system characterized by the following features.

3. A calculation unit that estimates the degradation state of multiple batteries. A storage unit that stores the data used by the aforementioned calculation unit, Equipped with, The calculation unit identifies among the plurality of batteries that require measures to be taken to address the deterioration of the state, The calculation unit calculates the costs necessary to implement the measures based on cost data that describes at least one of the changes in costs over time or predictions of costs associated with implementing the measures, Based on the calculated costs, the calculation unit determines which of the multiple measures can maximize economic effect and the timing of its implementation. The aforementioned measures are, Rebalancing to equalize the charge state of the aforementioned multiple batteries, Rebuilding the aforementioned battery, The aforementioned battery can be repurposed for other applications with different performance requirements. At least one of the following: The aforementioned cost data describes, as the aforementioned costs, at least one of the following: time-varying personnel costs incurred as a result of implementing the aforementioned measures, or time-varying equipment costs incurred as a result of implementing the aforementioned measures. The calculation unit calculates the economic effect by using at least one of the time-varying personnel costs or time-varying equipment costs described in the cost data to calculate the costs necessary to carry out the rebalancing, rebuilding, or conversion. A battery degradation management system characterized by the following features.

4. A calculation unit that estimates the degradation state of multiple batteries. A storage unit that stores the data used by the aforementioned calculation unit, Equipped with, The calculation unit identifies among the plurality of batteries that require measures to be taken to address the deterioration of the state, The calculation unit calculates the costs necessary to implement the measures based on cost data that describes at least one of the changes in costs over time or predictions of costs associated with implementing the measures, Based on the calculated costs, the calculation unit determines which of the multiple measures can maximize economic effect and the timing of its implementation. The aforementioned measures are, Rebalancing to equalize the charge state of the aforementioned multiple batteries, Rebuilding the aforementioned battery, The aforementioned battery can be repurposed for other applications with different performance requirements. At least one of the following: The calculation unit calculates the economic effect based on price data that describes at least one of the changes in the price of the battery over time or a prediction thereof. The aforementioned price data describes at least one of the following: the market price of used batteries, the market price of battery materials, the market price of new batteries, and forecasts of their changes over time. The calculation unit calculates the economic effects of each of the rebalancing, rebuilding, and diversion based on the price data described in the price data or the forecast of its change over time, and then determines which of the rebalancing, rebuilding, and diversion should be implemented as the measure. A battery degradation management system characterized by the following features.

5. A calculation unit that estimates the degradation state of multiple batteries. A storage unit that stores the data used by the aforementioned calculation unit, Equipped with, The calculation unit identifies among the plurality of batteries that require measures to be taken to address the deterioration of the state, The calculation unit calculates the costs necessary to implement the measures based on cost data that describes at least one of the changes in costs over time or predictions of costs associated with implementing the measures, Based on the calculated costs, the calculation unit determines which of the multiple measures can maximize economic effect and the timing of its implementation. The aforementioned measures are, Rebalancing to equalize the charge state of the aforementioned multiple batteries, Rebuilding the aforementioned battery, The aforementioned battery can be repurposed for other applications with different performance requirements. At least one of the following: The calculation unit calculates the economic effect based on price data that describes at least one of the changes in the price of the battery over time or a prediction thereof. The calculation unit selects the rebalancing as the measure if the economic effect of the rebalancing is equal to or greater than the fifth threshold. The calculation unit selects either the rebuild or the repurposing as the measure if the economic effect of the rebalancing is less than the fifth threshold. A battery degradation management system characterized by the following features.

6. The aforementioned cost data describes, as the aforementioned costs, at least one of the following: time-varying personnel costs incurred as a result of implementing the aforementioned measures, or time-varying equipment costs incurred as a result of implementing the aforementioned measures. The calculation unit calculates the economic effect using at least one of the time-varying personnel costs or time-varying equipment costs described in the cost data. A battery degradation management system according to any one of claims 1 to 5.

7. The calculation unit calculates the economic effect based on price data that describes at least one of the changes in the price of the battery over time or a prediction thereof. A battery degradation management system according to any one of claims 1 to 5.

8. The calculation unit selects the rebuild as the measure if the economic effect of the rebuild is equal to or greater than the sixth threshold. The calculation unit selects the repurposing as the measure if the economic effect of the rebuild is less than the sixth threshold. The battery degradation management system according to claim 5, characterized in that it is a battery degradation management system.

9. The calculation unit determines the content of the measures to be implemented based on environmental load data that describes indicators representing the environmental burden that will result from implementing the measures. A battery degradation management system according to any one of claims 1 to 5.

10. The aforementioned arithmetic unit, SOC-OCV data describing the relationship between the charge state of the battery and the open-circuit voltage of the battery, SOC-charging resistance data describing the relationship between the charge state of the battery and the charging resistance of the battery, SOC-discharge resistance data describing the relationship between the charge state of the battery and the discharge resistance of the battery, Obtain, The calculation unit estimates the degradation state of the battery by referencing the SOC-OCV data, the SOC-charging resistance data, and the SOC-discharge resistance data to estimate the change in the battery capacity of the battery over time. A battery degradation management system according to any one of claims 1 to 5.

11. The calculation unit acquires the measured values ​​of the voltage output by the battery, the current output by the battery, and the temperature of the battery, The calculation unit calculates the charge state of the battery by integrating the current over time, The calculation unit obtains the open-circuit voltage and the charging resistance of the battery by referring to the SOC-OCV data and the SOC-charging resistance data using the charging state, and corrects the charging resistance using the temperature. The calculation unit estimates the voltage using the charging resistance and the open-circuit voltage. The calculation unit calculates the battery capacity by using the SOC-discharge resistance data to calculate the SOC at the time discharge stops. The battery degradation management system according to claim 10, characterized in that it is a battery degradation management system.

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