JP2020181667A - Power storage system, battery sales method and battery counting system - Google Patents

Abstract

To determine distribution of the current to a plurality of batteries when a battery with a low price and short life and a battery with a high price and long life are mixed.SOLUTION: Disclosed is a power storage system in which a plurality of batteries and a control part are included. The control part acquires price information on each of the plurality of batteries and a value of the current or power required for the whole of the plurality of batteries and calculates a current lifetime ratio using the current deterioration sensitivity, then calculates the value of the current to be distributed to each of the plurality of batteries.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power storage system, a battery sales method, and a battery counting system.

Industrial power storage systems include, for example, a solar power generation system, a wind power generation system, and a peak cut system. Here, the peak cut system is a system that lowers the electricity rate by turning the electric power generated by photovoltaic power generation into self-consumption, reducing the amount of electric power, and lowering the contracted electric power.

In Patent Document 1, a plurality of storage batteries having different charge / discharge characteristics are used for the purpose of extending the life of the storage battery while further mitigating the fluctuation of the generated power of the power generation system, and the charge / discharge power command received by the receiving unit is used. Based on the history of values, an index value indicating the degree of spread of the distribution of charge / discharge power command values is calculated, and the storage battery to be charged / discharged is switched based on the calculated index value. Has been done.

Japanese Unexamined Patent Publication No. 2016-54607

The power assisting system described in Patent Document 1 is based on the premise that there is no price difference between a plurality of batteries used, and by switching the storage battery to be charged / discharged based on the charging / discharging situation. This is to extend the life of the battery.

However, when low-priced and short-life batteries such as used batteries are introduced to the market, it is more economical to intensively use cheap batteries to lower the average battery life cycle cost (LCC). Is.

An object of the present invention is to determine the distribution of current to a plurality of batteries when a battery having a low price and a short life and a battery having a high price and a long life are mixed.

The power storage system of the present invention includes a plurality of batteries and a control unit, and the control unit includes price information of each of the plurality of batteries and a value of current or electric power required for the entire plurality of batteries. And, the current life ratio is calculated using the current deterioration sensitivity, and the value of the current distributed to each of the plurality of batteries is calculated.

According to the present invention, when a battery having a low price and a short life and a battery having a high price and a long life are mixed, it is possible to determine the current distribution to a plurality of batteries.

It is a schematic block diagram which shows an example of the power storage system which concerns on 1st Embodiment. It is a graph which conceptually shows the acceleration of the deterioration of a battery. It is a graph for demonstrating the principle for estimating the current deterioration sensitivity. It is a graph which shows the estimation method of the current deterioration sensitivity of each of two batteries. It is a graph which shows the estimation method of the storage deterioration life. It is a graph which shows the example of the current distribution in this invention. It is a schematic block diagram which shows an example of the power storage system which concerns on 2nd Embodiment. It is a figure which shows the structure about the selling method of the battery of this invention. It is a graph which shows the current distribution when the power type battery and the capacity type battery are combined. It is a flow chart which shows the control method of the battery in the power storage system which concerns on 1st Embodiment.

First, the principle of the present invention will be described.

The life cycle cost (LCC) of the entire power storage system is Σ {C (C), where the initial cost of the battery k constituting the power storage system is C (k) and the battery life is Y _k (I (k), k). It is represented by k) ÷ Y _k (I (k), k)}. Here, I (k) is the current of the battery k.

It is an optimization problem whose purpose is to minimize LCC. Minimizing LCC is synonymous with minimizing running costs.

Battery life Y _k (I (k), k) is roughly a function of temperature and current.

In the case of an industrial power storage system, the temperature can be regarded as constant because it is installed in a container equipped with an air conditioner.

Therefore, if the above optimization problem is solved by Lagrange's undetermined multiplier method, the values of C (k) × f (k) ÷ Y _k (I (k), k) ² should be equal. Here, f is the current deterioration sensitivity [year / A] and is defined as ∂Y _k (I (k), k) / ∂I (k).

In the present invention, by means for obtaining the current deterioration sensitivity f (k) of each battery k, means for estimating g (k) = (C (k) × f (k)) ^0.5 , f and g. It has a means of determining the current distribution, determines the current distribution, and controls the battery current.

In the present invention, if the life of each battery is about the same, the operating cost is reduced by concentrating the current through the battery having a low initial cost (purchase price) and increasing the rotation of the cheap battery. If the initial cost is the same, the current is concentrated on the long-life battery to reduce the operating cost.

The initial cost of the battery is also referred to as "price information".

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and applications are included in the technical concept of the present invention. For example, the systems described below include not only solar and wind storage batteries and peak cut systems, but also HEMS (Home Energy Management System), BEMS (Billing Energy Management System), FEMS (Factority Energy), and FEMS (Factory Energy). Applicable. It can be said that this system is a system for planning the operation of different types of batteries.

One of the features of such a configuration is, for example, the following configuration.

Multiple types of batteries are prepared, and used battery packs and new battery packs are mixed in them, and a power adjustment subsystem (PCS: Power Conditioning Subsystem) that distributes current to each is also called a "power conditioner". The PCS can set the charge / discharge current by AC / DC conversion, and is equipped with a control controller that controls each PCS.

The general controller has a part that estimates the current deterioration sensitivity (the rate at which the life is shortened by increasing the charge / discharge current of the battery), the target life ratio calculation unit, and the current distribution based on the current deterioration sensitivity and the target life ratio. It has a desired current distributor. The initial cost of each battery pack and the current required for the battery system are input to the control controller.

According to the above configuration, the frequency of use of the battery can be determined according to the cost and the life, and the operating cost can be kept low by the time average (including battery replacement). The above configuration is an example, and the present invention is not limited to the above configuration.

In the following description, when the same type of elements are not distinguished, the common part (the part excluding the branch number) of the reference symbols including the branch number is used, and the same type of elements are distinguished and described. In some cases, a reference code containing the branch number may be used.

(1) First Embodiment This embodiment is an example having two types of batteries (battery packs).

FIG. 1 is a configuration diagram showing an example of a power storage system.

In this figure, the power storage system includes a control controller 10, power conditioners 12, 13 (PCS), and batteries 14, 15. The batteries 14 and 15 are connected to an external load 11 that supplies or consumes electric power. The load 11 is a solar cell system, a wind power generation system, an electric facility of a building, or the like. A power conditioner 12 is installed between the battery 14 and the load 11. A power conditioner 13 is installed between the battery 15 and the load 11. Here, the battery 14 is a new battery A (new battery), and the battery 15 is a used battery B (used battery). The power conditioners 12 and 13 are controlled by the control controller 10.

The integrated controller 10 has a program realized by any one of a PC (Personal Controller) or a business terminal, a PLC (Programmable Logical Controller) and an embedded microcomputer (Microcomputer), or a combination thereof.

The control controller 10 is composed of a current distribution unit 16, a target life ratio calculation unit 17, and a current deterioration sensitivity estimation unit 18. The current distribution unit 16 sends a command for each output to the power conditioners 12 and 13. The current deterioration sensitivity estimation unit 18 estimates the current deterioration sensitivity f of the batteries 14 and 15.

The control controller 10 receives the current or electric power requested by the load 11 side (referred to as "required current" and "required power", respectively). Further, the initial prices (initial values of costs) of the batteries 14 and 15 are input to the control controller 10. Then, the control controller 10 is sent an output value of the current or electric power distributed to each of the power conditioners 12 and 13.

The target life ratio calculation unit 17 records the initial values of the costs of the batteries 14 and 15, respectively. The target life ratio calculation unit 17 uses the initial value of the cost of each of the batteries 14 and 15 and the current deterioration sensitivity f of each of the batteries 14 and 15 estimated by the current deterioration sensitivity estimation unit 18, and the target life ratio λ. To calculate. The current distribution unit 16 calculates the output distribution (output current or output power ratio) of the batteries 14 and 15 using the current deterioration sensitivity f, the target life ratio λ, and the like, and issues a command to the power conditioners 12 and 13. send.

Hereinafter, the principle of the present invention will be described in detail.

First, the current deterioration sensitivity f is defined.

Battery deterioration is generally accelerated as the charge / discharge current to the battery increases.

FIG. 2 is a graph conceptually showing the acceleration of battery deterioration. The horizontal axis is the charge / discharge current, and the vertical axis is the battery life.

The charge / discharge current is a current value when a constant current is continuously applied. In the case of charging, charging is continued until the battery reaches full charge (the upper limit of the capacity in the battery specifications). On the other hand, in the case of discharge, discharge is continued until the lower limit of the capacity is reached. Since the direction of the current is different between charging and discharging, the horizontal axis is the absolute value of the current. Regarding the setting of the upper limit value and the lower limit value of charge / discharge, even if charging and discharging are repeated within the range of the standard deviation of the current, the same result as in this figure is obtained.

Battery life may be measured and estimated using the central SOC and DOD. Here, DOD is an abbreviation for Depth Of Discharge and means the depth of discharge. In other words, it is the capacity [Ah] when switching between discharging and charging.

In this figure, a graph is shown under the condition that the central SOC and DOD do not change, and only the current at the time of charging / discharging changes.

Similarly, the life of a battery changes depending on the temperature, but in the case of an industrial power storage system, the battery is generally stored in a container equipped with an air conditioner, so that the temperature can be considered to be constant. Further, since the upper limit value and the lower limit value of the SOC of the battery are set for the DOD, the central SOC and the DOD are substantially fixed.

In this figure, the larger the current, the shorter the life. That is, the slope of the curve is negative. In the region where the charge / discharge current is small, the slope of the curve is often almost constant. The value obtained by multiplying this slope (the slope in a portion where the slope is constant over a certain wide range) by (-1) is defined as the current deterioration sensitivity f.

This current deterioration sensitivity f is held as a constant if it is provided by the battery company and the value does not change (when the value does not change due to deterioration). However, if the battery company does not provide it, or if the value changes due to deterioration, it needs to be estimated by some method.

Hereinafter, this estimation method will be described.

In this method, a learning phase is provided at the beginning of system installation, immediately after replacing one battery, or regularly (every few years).

FIG. 3 is a graph for explaining the principle for estimating the current deterioration sensitivity f.

In this figure, the time course of SOH (capacity SOH) is shown when a load of current 0 and then current I (which is a standard deviation) is applied to one battery. The period of current 0 is represented by a broken line curve, and the period of current I is represented by a solid line curve. SOH can be measured or estimated by existing methods. SOH is an index indicating the deterioration state of the battery, and is an abbreviation for State Of Health.

As shown in this figure, the slope of SOH (rate of change over time) changes before and after changing the current from 0 to I (before and after switching the current). Regarding this slope, the value immediately before switching the current is m ₁ and the value immediately after switching is m ₂ .

Here, the SOH of the battery will be expressed by the following equation (1) as an approximate equation of the exponential function. In the formula, t is time, f is current deterioration sensitivity, I is current, and b is a constant.

In reality, SOH may deviate from the exponential function, but when the state of the battery is changed, a phenomenon of sudden discontinuity occurs, and the term expressed by the exponential function cannot be ignored. Therefore, it is approximated as an exponential function × a correction function. Since the term of the exponential function is large, the above equation (1) is obtained by approximating the coefficient of the exponential function with the current linear portion. Since the battery replacement is performed when the SOH reaches a certain value κ (for example, 0.7), the battery life T is approximated by the following formula (2) from the above formula (1). Κ is referred to as "exchange SOH".

On the other hand, from the above equation (1), m ₁ and m ₂ are approximated by the following equations (3) and (4).

Therefore, m ₁ ÷ m ₂ is approximated as (−fI + b) / b.

Therefore, f is given by the following equation (5).

Since b remains on the right side of the above equation (5), I = 0 is substituted into the above equation (2) and used as T = -log (κ) × b. In this case, T is the battery life (preservation deterioration life L) when the current is 0. That is, when the current is 0, T becomes equal to the storage deterioration life L. Therefore, in this case, b = −L / log (κ), and f is determined as the following equation (6).

Therefore, if L is known, f can be calculated.

Next, a method for measuring the current deterioration sensitivity when two batteries are used will be described.

FIG. 4 is a graph showing the time course of SOH of each of the two batteries. In the figure, the battery A is shown by a solid line curve, and the battery B is shown by a broken line curve.

As shown in this figure, in the first half, the current of the battery A is set to 0 and only the battery B is used for several months, and in the second half, the current of the battery B is set to 0 and only the battery A is used for several months. The slope of the curve is calculated using the measured value of this SOH. Assuming that the standard deviation of the current in each period in which only battery A or only battery B is used is I, in principle, the current deterioration sensitivity f of battery A and battery B can be obtained by using the above equation (6). Be done.

In the figure, the slope of the SOH before and after the switching of the cell using the value of switching immediately before a battery A and m _A1, the value immediately and m _A2, the value of the switching immediately before a battery B m _B1, immediately after the value _Let m _B2 . In this case, when the above equation (6) is applied, the current deterioration sensitivity f _{A of} the battery _A and the current deterioration sensitivity f _B of the battery B can be calculated by the following equations (7) and (8), respectively. The subscripts A and B mean that they correspond to the battery A and the battery B, respectively.

If the storage deterioration life L is provided by the manufacturer, it can be used. When the storage deterioration life L is unknown, it is estimated by the following method.

FIG. 5 is a graph showing changes over time in SOH when batteries A and B are used under the same conditions as in FIG. In the figure, the solid line curve is the SOH actually measured with the battery current set to 0, and the broken line curve is the SOH obtained by exponentially extrapolating when the state of the solid line curve continues thereafter. Is. In addition, you may simply extrapolate by a straight line having the slope of the curve at the right end of the curve in practice.

Each time the value indicated by the dashed curve of the battery A and the battery B has a value of exchange SOH _(κ), L A, and L _B.

Through the steps as described above, the current deterioration sensitivity estimation unit 18 in FIG. 1 estimates the current deterioration sensitivities f _A and f _B, and saves the results as data. That is, in the power storage system, when a new battery is connected or when the battery is replaced, the control controller 10 in FIG. 1 learns about the battery (learning phase). The estimated results are also accumulated for the storage deterioration life L.

The target life ratio calculation unit 17 of FIG. 1 stores the input battery cost data (initial value).

Here, the cost C _A battery _A, the cost of the battery B and C _B, current deterioration sensitivity f _A, with f _B, obtains the value of the target life ratio λ by the following equation (9).

Next, the current distribution unit 16 of FIG. 1 will be described.

FIG. 6 is a graph showing an example of current distribution. The horizontal axis represents the absolute value of the required current from the host system (for example, the load 11 side in FIG. 1), and the vertical axis represents the absolute value of the current distributed to each of the two batteries. Here, a negative value (this is defined as "discharge" and a positive value is defined as "charge"), for example, when -100A is the required current, the value on the horizontal axis 100A is specified. .. When the values of the battery A are 80A and the values of the battery B are 20A, the current of -80A is actually distributed to the battery A and the current of -20A is distributed to the battery B.

In FIG. 6, the battery A and the battery B are each divided into straight lines. In this example, current deterioration in the battery A and the battery B sensitivity f _A, f _B, and the cost C _A, C _B are equivalent, storage deterioration life L is a shorter direction of the battery A. Therefore, since the battery B has a longer life, the solution is to concentrate the current on the battery B. Then, in the range where the absolute value of the required current is equal to or less than the threshold value, the current of the battery A is set to 0 as shown in this figure.

Next, a method of obtaining the division straight line shown in FIG. 6 will be described.

By approximating the battery life to Lf × I and substituting the minimum cost condition “λ × battery B life (I _b ) = battery A life (I _a )”, the following equation (10) is obtained. .. The subscripts a and b mean that they correspond to the battery A and the battery B, respectively.

However, since a negative value is not allowed for the current I _b obtained by the above equation (10), if it becomes a negative value, the current is set to 0.

Then, in this example, since the total of the battery A and the battery B is equal to the required current in the system, the following equation (11) holds.

By solving the above equations (10) and (11) at the same time, the following equations (12) and (13) are obtained.

Here, in the above equations (12) and (13), since it is not allowed that the right side has a negative value, it is set to 0 when the calculation result becomes negative.

This is summarized in FIG.

In this case, since the instantaneous value of I is distributed as it is, it holds true regardless of whether the charge / discharge current on the horizontal axis is the standard deviation or the absolute value in FIG.

However, the power storage system may not have a battery charge / discharge period, and the above discussion may not hold. This case will be described below.

First, the capacity _{Q b} of the capacitor _{Q a} and the battery B of the battery A, is calculated using the following equation (14) and (15).

Next, the planned current distribution is determined by the following equations (16) and (17).

If the current is negative in this solution, the current is set to zero. Here, if Qa = Qb ÷ λ, the current distribution shown in FIG. 6 is obtained.

In addition, the combination of the power type battery (the current deterioration sensitivity is small and the cost is high) and the capacity type battery (the current deterioration sensitivity is large and the cost is low) gives the solution as shown in FIG. 9 instead of FIG. In FIG. 9, the battery A is a power type and the battery B is a capacity type. The vertical axis and the horizontal axis of this figure are the same as those of FIG.

It is assumed that the target life ratio λ is sufficiently larger than 1. Then, _{L a} is sufficiently less than the .lambda.L _b, and tend to .lambda.f _b is sufficiently larger than _{f a.}

In this case, in the above formula (12), the intercept of _Ia becomes negative and the slope approaches 1.

The meaning of FIG. 9 is that, for the current below the threshold value, if the value is below the threshold value, the capacity type battery bears the current, and the power type battery shares the current exceeding the threshold value to reduce the operating cost. The current distribution unit normally operates, receives the required current every cycle (for example, 0.1 s), and sends a command to the PCS.

Further, the current distribution unit does not specify the value, but the battery life may be "battery A life = λ x battery B life", so that the distribution ratio may be increased or decreased. .. Battery life can be estimated from the SOH history of the last few months. Then, if "battery A life <λ x battery B life", the current distribution ratio to battery B is increased, and if "battery A life> λ x battery B life", the current distribution to battery A is increased. , If "battery A life ≒ λ x battery B life", the current allocation is maintained. This proportional distribution is updated regularly (every few months).

FIG. 10 summarizes the above-mentioned contents of the battery control method in the power storage system according to the first embodiment.

As shown in this figure, in the power storage system, when the battery pack is replaced or added, the cost (purchase cost) of the battery pack is input (S110).

The current, SOH, etc. of each battery pack are measured (S120). The current deterioration sensitivity f is calculated using the slope of SOH shown in FIG. 3 and the like (S130). The target life ratio λ is calculated using the current deterioration sensitivity f and the like (S140).

Acquire the required current I (S150).

The value of the distributed current is calculated by the method shown in FIG. 6 and the like (S160).

A command is sent to each battery pack based on the result of step S160 (S170).

As a result, the effect of reducing the running cost of the battery can be obtained.

(2) Second Embodiment FIG. 7 shows an example of a power storage system according to the second embodiment.

This figure is an example when three or more battery packs are included.

Hereinafter, only the differences from FIG. 1 will be described.

In FIG. 7, the power storage system includes power conditioners 113a, 113b, 113n and batteries 115a, 115b, 115n. The batteries 115a, 115b, 115n are connected to an external load 11 that supplies or consumes electric power via the power conditioners 113a, 113b, 113n, respectively.

In the learning phase of the current deterioration sensitivity f, the currents of the batteries 115a, 115b, and 115n are sequentially set to 0, and the remaining batteries are used. In the same manner as in the above formula (9), the target life is based on the first battery 115a. Calculate the ratio λ.

The following formula (18) is a calculation formula when the current of the second battery 115b is sequentially set to 0 and the remaining batteries are used. Further, the following formula (19) is a general formula, which is a calculation formula when the current of the nth battery is sequentially set to 0 and the remaining batteries are used (n is an integer of 3 or more).

And, as the formula of current distribution, battery 1 life (battery 1 current) = λ ₂ × battery 2 life (battery 2 current) = ... = λ _n × battery n life (battery n current) and Σ battery k current = Solve the equation that makes I (required current) simultaneous. If a negative solution is obtained, the value is set to 0.

When the current distribution is calculated using the above equations (16) and (17), Q _k is calculated using the following equation (20) instead of the above equations (14) and (15).

Then, instead of the above equations (16) and (17), the simultaneous equations of the following equations (21) and (22) are solved.

As described above, even if there are n battery packs, it can be handled.

(3) Other Embodiments The present embodiment relates to a system or method for collecting and selling information in the secondary market of batteries including used batteries.

The first embodiment and the second embodiment are for the case where a battery is actually used. However, if there is information about the current deterioration sensitivity f when selling the battery, it will be added value to the battery. This system will be described.

This can be done by a battery pack dealer measuring the current deterioration sensitivity f using a device and adding information as added value when selling the battery, or by a dealer using an electric vehicle (EV) reselling a used battery. At that time, the current deterioration sensitivity f may be obtained based on the data in use and resold. Each will be described.

When a battery packer measures the current deterioration sensitivity f using a charging / discharging device, the current deterioration sensitivity f is obtained by the principle of FIG.

In the case of a company that uses an electric vehicle, a mechanism for collecting OBD data of the electric vehicle will be provided. Here, the OBD refers to an on-board diagnostic device (OBD: On-Board Diagnostics). It is assumed that the OBD includes the battery current, voltage, temperature, SOC, and SOH time series. Then, the OBD shall be collected in the upper center server via the communication device.

FIG. 8 schematically shows a configuration related to a method for selling a battery of the present invention, and shows an IoT system (battery counting system) of an EV supplier or the like.

In this figure, the center server is a component of the battery aggregation system, and has a database, an aggregation unit, an input unit, an output unit, and the like. The center server acquires the standard deviation of the current, the center SOC, the average temperature of the battery, the DOD, the history of SOH, etc. (history information) for each vehicle (EV, etc.) and stores them in the database.

Next, only the same battery model number of each vehicle is totaled, and the current deterioration sensitivity f is totaled. By taking the battery life on the vertical axis and the current standard deviation of each company on the horizontal axis (graph on the upper right of this figure), the current deterioration sensitivity f can be obtained from the slope of the curve (straight line) obtained from the aggregated data. The current deterioration sensitivity f is presented as product information when the battery is sold.

For the battery life, for example, the number of years until the SOH (EV pattern) 0.7 is used (this can be obtained from the SOH history). However, the temperature should be the same (for example, only 25 ° C.). Here, the number of years on the vertical axis is different from that for industrial use, but from the relationship of the above equation (2), the value is multiplied by a constant even for industrial use, and is established as a proportional relationship.

However, in the case of individual batteries, there is a possibility that they have deteriorated, and the values may deviate. In that case, the slope of a straight line connecting the point of storage deterioration (the EV that is rarely used is a representative point) and the point of the corresponding vehicle is used.

Hereinafter, the battery sales method and the battery counting system according to the present embodiment will be summarized.

The battery sales method is to acquire and accumulate historical information including (1) history of battery deterioration state and battery current standard deviation, and (2) estimate battery life from the history of deterioration state. (3) The current deterioration sensitivity of the battery is calculated from the battery life and the current standard deviation of the battery, and (4) the current deterioration sensitivity is presented as product information when the battery is sold.

This makes it possible to promote the supply of batteries that are easily adapted to the power storage system in the distribution process of batteries including used batteries.

The historical information includes the average temperature of the battery.

The current degradation sensitivity is calculated for batteries of the same type.

The battery aggregation system includes a database, an aggregation unit, and an output unit. (1) The database acquires and accumulates history information including the history of the deterioration state of the battery and the current standard deviation of the battery. , (2) The aggregation unit estimates the battery life from the history of deterioration status, calculates the battery current deterioration sensitivity from the battery life and the battery current standard deviation, and stores the current deterioration sensitivity in the database. (3) The output unit presents the current deterioration sensitivity as product information when the battery is sold.

This makes it possible to promote the provision of product information of batteries applied to the power storage system in the distribution process of batteries including used batteries.

Further, the above-mentioned configuration may be appropriately changed, rearranged, combined, or omitted as long as the gist of the present invention is not exceeded.

According to the present invention, the life of the battery can be extended.

10: Control controller, 11: Load, 12, 13: Power conditioner, 14, 15: Battery, 16: Current distribution unit, 17: Target life ratio calculation unit, 18: Current deterioration sensitivity estimation unit.

Claims (11)

With multiple batteries
With a control unit
The control unit acquires the price information of each of the plurality of batteries and the value of the current or electric power required for the entire plurality of batteries, and calculates the current life ratio using the current deterioration sensitivity. A power storage system that calculates the value of the current distributed to each of the plurality of batteries. The control unit provides a period in which the current of any one of the plurality of batteries is set to 0, and then energizes the control unit, and changes over time in the deteriorated state of the one battery immediately before and after the energization. The power storage system according to claim 1, wherein the current deterioration sensitivity is calculated from the rate. The power storage system according to claim 2, wherein the current deterioration sensitivity is calculated after replacing the one battery or periodically. In the magnitude relationship considering the current life ratio with respect to the life of any two batteries of the plurality of batteries, a large amount of current is distributed to the larger battery, and the two batteries are equal in the magnitude relationship. The power storage system according to claim 2, wherein the current distribution is maintained in the case of the case. The power storage system according to claim 4, wherein the current distribution is adjusted periodically. History information including the history of the deterioration state of the battery and the current standard deviation of the battery is acquired and accumulated.
The life of the battery is estimated from the history of the deteriorated state, and the life of the battery is estimated.
The current deterioration sensitivity of the battery is calculated from the life of the battery and the current standard deviation of the battery.
A battery sales method in which the current deterioration sensitivity is presented as product information when the battery is sold. The method for selling a battery according to claim 6, wherein the history information includes the average temperature of the battery. The method for selling a battery according to claim 6, wherein the current deterioration sensitivity is calculated for the same type of battery. It has a database, an aggregation unit, and an output unit.
The database acquires and accumulates history information including the history of the deterioration state of the battery and the current standard deviation of the battery.
The aggregation unit is
The life of the battery is estimated from the history of the deteriorated state, and the life of the battery is estimated.
The current deterioration sensitivity of the battery is calculated from the life of the battery and the current standard deviation of the battery.
The current deterioration sensitivity is transmitted to the database as product information,
The output unit is a battery counting system that presents the current deterioration sensitivity as the product information at the time of selling the battery. The battery counting system according to claim 9, wherein the history information includes the average temperature of the battery. The battery counting system according to claim 9, wherein the current deterioration sensitivity is calculated for the same type of battery.

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