JP6365938B2 - DESIGN DEVICE, DESIGN METHOD, AND PROGRAM - Google Patents

Description

  The present invention relates to a design device, a design method, and a program for designing a power storage device.

  A power storage device that stores power in a storage battery and extracts the power from the storage battery as needed is drawing attention. For example, with the recent increase in power saving intentions, the increase in power consumption can be suppressed, or power can be charged at night and discharged during the day. Power storage devices are used for purposes such as suppressing purchases. In particular, in places where power consumption is large, such as commercial facilities and factories, power storage devices having a large capacity are becoming widespread in order to cope with the large power consumption. Such a power storage device realizes a large capacity by using an assembled battery in which tens to tens of thousands of storage battery cells are combined in series and parallel as a storage battery. For example, a power storage device having a capacity of 2 MWh is realized by combining 200,000 18650 type storage battery cells having a capacity of 10 Wh.

  Further, in the power storage device, the product life of the manufactured product is set in consideration of deterioration of the power storage location according to aging, the number of times of use, and the like. At this time, if the set product life is deviated from the appropriate value, product failure will occur before the life, or the storage battery will be replaced more quickly than necessary, increasing maintenance and replacement costs. Resulting in.

  On the other hand, Patent Document 1 describes a deterioration determination device that grasps a remaining life by accurately grasping a remaining capacity of a storage battery cell constituting an assembled battery used in a power storage device.

JP 2006-300561 A

  In a power storage device including an assembled battery having a large number of storage battery cells as described above, manufacturing variations and aging variations in the capacity of storage battery cells are likely to become obvious, so using a technique such as that described in Patent Document 1, Even if the life of the storage battery cells constituting the assembled battery is accurately grasped, it is difficult to predict the life of the assembled battery itself.

  For example, the life of an assembled battery is generally shorter than the life of a single storage battery cell due to the effect of variations in the storage battery cells. Therefore, it will be predicted longer than actual. In this case, a malfunction of the product occurs before the set product life, and the power storage device often cannot achieve the product life.

  The objective of this invention is providing the design apparatus, the design method, and program which can evaluate the lifetime of the assembled battery comprised with a some storage battery cell accurately.

The design device according to the present invention comprises:
Statistical cell degradation characteristics for deriving statistical cell degradation characteristics, which are statistical data related to the plurality of cell degradation characteristics, based on a plurality of cell degradation characteristics that are respective degradation characteristics of the plurality of storage battery cells used in the assembled battery A derivation unit;
An operation for deriving a statistical assembled battery deterioration characteristic that is evaluation data for evaluating the deterioration characteristic of the assembled battery from the statistical cell deterioration characteristic based on connection structure information indicating a connection structure between the plurality of storage battery cells A calculation procedure deriving unit for deriving the procedure;
A statistical assembled battery deterioration characteristic deriving unit for deriving the statistical assembled battery deterioration characteristic from the statistical cell deterioration characteristic according to the calculation procedure;
A life evaluation unit that evaluates the life of the assembled battery based on the statistical assembled battery deterioration characteristics.

The design method according to the present invention comprises:
Based on a plurality of cell deterioration characteristics that are respective deterioration characteristics of a plurality of storage battery cells used in the assembled battery, a statistical cell deterioration characteristic that is statistical data related to the plurality of cell deterioration characteristics is derived,
An operation for deriving a statistical assembled battery deterioration characteristic that is evaluation data for evaluating the deterioration characteristic of the assembled battery from the statistical cell deterioration characteristic based on connection structure information indicating a connection structure between the plurality of storage battery cells Deriving the procedure
Deriving the statistical battery pack deterioration characteristic from the statistical cell deterioration characteristic according to the calculation procedure,
The life of the assembled battery is evaluated based on the statistical assembled battery deterioration characteristics.

The program according to the present invention is:
A function of deriving statistical cell deterioration characteristics, which are statistical data related to the plurality of cell deterioration characteristics, based on a plurality of cell deterioration characteristics that are respective deterioration characteristics of the plurality of storage battery cells used in the assembled battery;
An operation for deriving a statistical assembled battery deterioration characteristic that is evaluation data for evaluating the deterioration characteristic of the assembled battery from the statistical cell deterioration characteristic based on connection structure information indicating a connection structure between the plurality of storage battery cells The ability to derive procedures;
A function of deriving the statistical assembled battery deterioration characteristic from the statistical cell deterioration characteristic according to the calculation procedure;
Based on the statistical assembled battery deterioration characteristic, a function of evaluating the life of the assembled battery is realized by a computer.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to evaluate the lifetime of the assembled battery comprised with a some storage battery cell accurately.

It is a figure which shows the structure of the design apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the flow of a process and the flow of information in the design apparatus which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating more specifically the function of the statistical cell degradation characteristic derivation | leading-out part which concerns on the 1st Embodiment of this invention. It is a figure explaining the calculation procedure corresponding to the assembled battery in which the some storage battery cell was connected in series. It is a figure explaining the calculation procedure corresponding to the assembled battery in which the some storage battery cell was connected in parallel. It is a figure explaining the calculation procedure corresponding to the assembled battery in which the some storage battery cell was connected in series-parallel. It is a flowchart for demonstrating more specifically the process which a statistical assembled battery deterioration characteristic derivation | leading-out part performs. It is a figure for demonstrating more specifically the process which a lifetime distribution derivation | leading-out part performs. It is a flowchart for demonstrating an example of operation | movement of the design apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the cell degradation characteristic which concerns on the 2nd Embodiment of this invention. It is a figure which shows an example of the lifetime distribution which concerns on the 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to what has the same function, and the description may be abbreviate | omitted. In addition, the components of the design apparatus according to the embodiment of the present invention described below indicate functional units, not hardware units. These functional unit components are realized by, for example, a combination of hardware and software. The hardware includes a computer such as a CPU (Central Processing Unit), a memory loaded with a program for defining the operation of the computer, a recording medium such as a hard disk for storing the program, and various interfaces such as a network connection interface. Interface. Examples of software include the above programs.

(First embodiment)
FIG. 1 is a diagram showing a configuration of a design apparatus according to the first embodiment of the present invention. FIG. 2 is a diagram showing a flow of processing and a flow of information in the design apparatus according to the first embodiment of the present invention.

  A design device 100 shown in FIGS. 1 and 2 is a device for designing a power storage device having, as a storage battery, an assembled battery in which a plurality of storage battery cells are combined. In addition, the design apparatus 100 includes a storage unit 101, a statistical cell deterioration characteristic deriving unit 102, a calculation procedure deriving unit 103, a statistical assembled battery deterioration characteristic deriving unit 104, and a life distribution deriving unit 105.

  The storage unit 101 stores various information necessary for designing the power storage device. Specifically, the storage unit 101 stores cell deterioration characteristics 201, connection structure information 202, and lifetime threshold information 203.

  The cell deterioration characteristic 201 is a deterioration characteristic of a storage battery cell used in the assembled battery included in the power storage device. In this embodiment, the memory | storage part 101 shall memorize | store the several cell deterioration characteristic 201 corresponding to each of several storage battery cells. In addition, the memory | storage part 101 may memorize | store the cell deterioration characteristic 201 corresponding to all the storage battery cells used with an assembled battery, or several storage battery cells sampled from all the storage battery cells used with an assembled battery May be stored.

  Specifically, the cell deterioration characteristic 201 indicates a correspondence relationship between a life factor scale that is a value related to a factor affecting the deterioration of the storage battery cell and a deterioration scale that is a value related to the degree of deterioration of the storage battery cell. The life factor scale includes, for example, the elapsed usage time of the storage battery cell, the number of charge / discharge cycles of the storage battery cell, the total amount of current charged or discharged by the storage battery cell, or a combination thereof. The degradation scale is, for example, a capacity scale that is a value related to the capacity of the storage battery cell. As a capacity | capacitance scale, charge capacity (CCAP: Charge CAPacity), discharge capacity (DCAP: Discharge CAPacity), capacity | capacitance maintenance factor (SOH; State Of Health), or these combination etc. are mentioned, for example.

  In the following, for simplicity of explanation, it is assumed that the life factor scale is the number of charge / discharge cycles, and the life scale is the charge capacity. In this case, assuming that the cell number that identifies the storage battery cell is No, the number of charge / discharge cycles is Cyc, and the charge capacity is CCAP, the cell deterioration characteristic 201 uses the function f to express the correspondence between the life factor scale and the deterioration scale. , CCAP = f (Cyc; No). The cell deterioration characteristic 201 indicates this correspondence using a mathematical expression or a table.

  The connection structure information 202 indicates a connection structure between storage battery cells constituting an assembled battery included in the power storage device. In addition, each of the storage battery cell is connected in series, parallel, or series-parallel.

  The life threshold information 203 indicates a life threshold CCAPth that is a threshold for evaluating the life of the assembled battery included in the power storage device.

  The statistical cell deterioration characteristic deriving unit 102 derives and outputs a statistical cell deterioration characteristic 204 that is statistical data related to the plurality of cell deterioration characteristics 201 based on the plurality of cell deterioration characteristics 201 stored in the storage unit 101. To do. Specifically, the statistical cell deterioration characteristic 204 is data indicating the frequency distribution of the charge capacity for each number of charge / discharge cycles. Note that the cell deterioration characteristics 201 used to derive the statistical cell deterioration characteristics 204 may be all the cell deterioration characteristics 201 stored in the storage unit 101 or all the cell deterioration characteristics stored in the storage unit 101. A plurality of cell deterioration characteristics 201 sampled from 201 may be used.

  Hereinafter, the probability Pr of having a certain charge capacity CCAP0 at a certain number of charge / discharge cycles Cyc0 is expressed as Pr = fsingle (Cyc0, CCAP0). Further, the frequency distribution of the charge capacity at a certain number of charge / discharge cycles Cyc0 is represented as fsingle (Cyc0, :), and the random variable x according to the frequency distribution is represented as x to fsingle (Cyc0, :). Further, the frequency distribution of the charge capacity for each number of charge / discharge cycles is collectively expressed as fsingle (:, :).

  FIG. 3 is a diagram for more specifically explaining the function of the statistical cell deterioration characteristic deriving unit 102. FIG. 3 shows cell deterioration characteristics CCAP = f (Cyc; 1) to CCAP = f (Cyc; 5) of five storage battery cells (cells 1 to 5) having cell numbers No. 1 to 5.

  The statistical cell deterioration characteristic deriving unit 102 is a deterioration scale corresponding to the charge / discharge cycle number Cyc for each charge / discharge cycle number Cyc, which is a life factor scale, based on the cell deterioration characteristics of the cells 1 to 5. The frequency distribution fsingle (Cyc, :) of the charge capacity CCAP is obtained. Then, the statistical cell deterioration characteristic deriving unit 102 derives data fsingle (:, :) indicating the frequency distribution of the charge capacity for each number of charge / discharge cycles as the statistical cell deterioration characteristic 204. Note that the statistical cell deterioration characteristic 204 can indicate these frequency distributions using mathematical expressions, tables, moments, various metrics, and the like.

  FIG. 3 shows the frequency distributions fsingle (10, :) and fsingle (100, :) of the charge capacity CCAP when the number of charge / discharge cycles Cyc is 10 cycles and 100 cycles. In the frequency distribution fsingle (10, :) of the charge capacity CCAP when the number of charge / discharge cycles Cyc is 10 cycles, the average is close to the design capacity of the power storage system, and the variance becomes small. This is because the storage battery cell capacity is almost equal to the design capacity because the influence of the storage battery cell manufacturing variation is small, but the effect is small at the start of use or shortly after the start of use of the power storage device. It is believed that there is. On the other hand, in the frequency distribution fsingle (100, :) of the charge capacity CCAP when the number of charge / discharge cycles Cyc is 100 cycles, the average is smaller and the variance is larger than when the charge / discharge cycle number Cyc is 10 cycles. ing. This is considered to be because the variation in capacity of each storage battery cell increases due to variation in the degree of deterioration due to an increase in the number of charge / discharge cycles Cyc and the elapsed time.

  Returning to the description of FIG. 1 and FIG. The calculation procedure deriving unit 103 derives a calculation procedure x_order for deriving the statistical assembled battery deterioration characteristic 206 from the statistical cell deterioration characteristic 204 based on the connection structure information 202 stored in the storage unit 101. Calculation procedure information 205 indicating x_order is output. The statistical assembled battery deterioration characteristic 206 is evaluation data for evaluating the deterioration characteristic of the assembled battery, and specifically, data indicating a frequency distribution (probability distribution) for estimating the charging capacity of the assembled battery for each number of charge / discharge cycles. It is.

  Specifically, the calculation procedure x_order is a procedure for correcting the frequency distribution of the charge capacity corresponding to the number of charge / discharge cycles for each number of charge / discharge cycles, and the corrected frequency distribution is the frequency with respect to the charge capacity of the assembled battery. It is determined to be a distribution.

  More specifically, the calculation procedure x_order includes an operator applied to a random variable that follows the frequency distribution of the charge capacity of the storage battery cell, and an operation order in which the operator is applied. The operator is determined according to individual connection relationships between the plurality of storage battery cells. Assuming that a random variable that follows the frequency distribution of the charge capacity is given as the charge capacity of the storage battery cell, the operator and the calculation order are applied in this calculation order to the random variable. The obtained value is determined to be the charge capacity of the assembled battery.

FIG. 4 is a diagram illustrating a calculation procedure corresponding to an assembled battery in which a plurality of storage battery cells are connected in series. In the example of FIG. 4, the assembled battery has a configuration in which three storage battery cells (cells A to C) are connected in series. Further, it is assumed that random variables xa to xc according to the frequency distribution of the charge capacity corresponding to a certain number of charge / discharge cycles Cyc0 are given as the charge capacities of the cells A to C as follows.
xa to fsingle (Cyc0, :), xb to fsingle (Cyc0, :), xc to fsingle (Cyc0, :).

  As shown in FIG. 4, when the cells A to C constituting the assembled battery are connected in series, the charge capacity x_all of the assembled battery is limited to the smallest charge capacity among the charge capacities of the cells A to C. Therefore, it is possible to calculate x_all = min (xa, xb, xc) using the minimum value operator min (). For this reason, the calculation procedure deriving unit 103 derives the minimum value operator min () as an operator when the connection relation of the storage battery cells is in series.

The minimum value operator min (xa, xb, xc) is an operator that calculates the smallest value among xa, xb, and xc. The polynomial operator in the minimum value operator min () can be expressed as a repetition of the binary operator as follows.
x_all = min (min (xa, xb), xc) = min (min (xb, xc), xa) = min (min (xc, xa), xb).

  FIG. 5 is a diagram illustrating a calculation procedure corresponding to an assembled battery in which a plurality of storage battery cells are connected in parallel. In the example of FIG. 5, the assembled battery has a configuration in which three storage battery cells (cells A to C) are connected in parallel. Assume that random variables xa, xb, and xc are given as the charge capacities of the cells A to C as in the example of FIG. In this case, since the charge capacity x_all of the assembled battery is the sum of the charge capacities of the cells A to C connected in parallel, x_all = add (xa, xb, xc) using the sum operator add () ) And can be calculated. For this reason, the calculation procedure deriving unit 103 derives the sum operator add () as an operator when the connection relation of the storage battery cells is in series.

  The sum operator add (xa, xb, xc) is an operator that calculates the sum of xa, xb, and xc. Further, a polynomial operation in the sum operator add () can be expressed as a repetition of a binary operation, similarly to the polynomial operation in the minimum value operator min ().

  In this example, the charge capacity that is not normalized as the degree of deterioration is used. However, when a normalized measure such as the capacity maintenance rate SOH is used instead of the charge capacity, the calculation procedure deriving unit 103 needs to derive an average value operator for calculating the average value of the random variable instead of the sum operator add () as an operator.

FIG. 6 is a diagram illustrating a calculation procedure corresponding to an assembled battery in which a plurality of storage battery cells are connected in series and parallel. In the example of FIG. 6, one storage battery cell (cell A), two storage battery cells (cells B and C) connected in parallel, and three storage battery cells (D, E, and F) connected in parallel Are connected in series. Further, it is assumed that random variables xa to xf according to the frequency distribution of the charge capacity corresponding to a certain number of charge / discharge cycles Cyc0 are given as the charge capacities of the cells A to F as follows.
xa to fsingle (Cyc0, :), xb to fsingle (Cyc0, :), xc to fsingle (Cyc0, :), xd to fsingle (Cyc0, :), xe to fsingle (Cyc0, :), xf to fsingle (Cyc0) , :).

In this case, the calculation procedure deriving unit 103 calculates the charge capacity x_all of the assembled battery by the sum operator add () corresponding to the storage battery cells connected in parallel and the minimum value operator corresponding to the battery cells connected in series. The following is calculated as a combination with min ().
x_all = min (xa, add (xb, xc), add (xd, xe, xf))

Note that the above polynomial operation can be expressed as a repetition of the following binary operation as in the case of only the minimum value operation min () or the sum operation add ().
x_all = min (min (xa, add (xb, xc)), add (add (xd, xe), xf)) = min (min (xa, add (xb, xc)), add (add (xd, xe ), Xf))

As described above, the operation order in which the operators are applied is not uniquely determined, and there may be a plurality of orders in which equivalent results are calculated. In the calculation procedure x_order, the operator and the calculation order may be expressed by a calculation tree as shown in the right diagram of FIG. 6, or by a topological ordering generated according to a certain rule. Also good. Note that the topology order corresponding to the example of FIG. 6 is expressed as follows.
1) x_bc = add (xb, xc)
2) x_def = add (xd, xe, xf)
3) x_all = min (xa, x_bc, x_def)

  Returning to the description of FIG. 1 and FIG. The statistical assembled battery deterioration characteristic deriving unit 104 calculates the calculation procedure x_order indicated by the calculation procedure information 205 output from the calculation procedure deriving unit 103 based on the statistical cell deterioration characteristic 204 output from the statistical cell deterioration characteristic deriving unit 102. The statistical battery deterioration characteristics 206 are derived according to Specifically, the statistical assembled battery deterioration characteristic deriving unit 104 recharges the assembled battery with a distribution obtained by correcting the frequency distribution of the charge capacity corresponding to the number of charge / discharge cycles according to the calculation procedure x_order for each number of charge / discharge cycles. Data shown as a probability distribution of capacity is derived as the statistical battery pack deterioration characteristic 206.

  FIG. 7 is a flowchart for more specifically explaining the process performed by the statistical assembled battery deterioration characteristic deriving unit 104.

  As shown in FIG. 7, the statistical assembled battery deterioration characteristic deriving unit 104 calculates a charge capacity frequency distribution fsingle (Cyc0, :) at a certain charge / discharge cycle number Cyc0 for a certain charge / discharge cycle number Cyc0 according to a calculation procedure x_order. Correction is performed to derive the frequency distribution fmodule (Cyc0, :) of the charge capacity of the assembled battery at the number of charge / discharge cycles Cyc0 (step S701). Specifically, the statistical assembled battery deterioration characteristic deriving unit 104 applies the operator indicated by the calculation procedure x_order to the random variable according to the frequency distribution fsingle (Cyc0, :) in the calculation order indicated by the calculation procedure x_order. The frequency distribution followed by the total random variable is derived as the frequency distribution fmodule (Cyc0, :) of the charge capacity of the assembled battery at the number of charge / discharge cycles Cyc0.

  The statistical assembled battery deterioration characteristic deriving unit 104 then repeats the process of step S701 for all the charge / discharge cycle times in the statistical cell deterioration characteristic 204 (step S702). The statistical assembled battery deterioration characteristic deriving unit 104 derives a set of frequency distributions fmodule (Cyc, :) of the charging capacity of the assembled battery for each charge / discharge cycle number Cyc as a statistical assembled battery deterioration characteristic 206 fmodule (:, :). To do.

  Returning to the description of FIG. 1 and FIG. The life distribution deriving unit 105 is also called a life evaluation unit. The life distribution deriving unit 105 calculates the life of the assembled battery based on the statistical assembled battery deterioration characteristic 206 output from the statistical assembled battery deterioration characteristic deriving unit 104 and the life threshold information 203 stored in the storage unit 101. evaluate. In the present embodiment, the life distribution deriving unit 105 is a frequency distribution of the number of charge / discharge cycles when the deterioration scale is the life threshold value CCAPth indicated by the life threshold value information 203 as an evaluation result of evaluating the life of the assembled battery. Derives and outputs the life distribution of the assembled battery.

  FIG. 8 is a diagram for more specifically explaining the process performed by the life distribution deriving unit 105. FIG. 8A shows the statistical assembled battery deterioration characteristic 206 output from the statistical assembled battery deterioration characteristic deriving unit 104. FIG. 8B shows a frequency distribution fmodule (Cyc0, :) of the charge capacity of the assembled battery at a certain number of charge / discharge cycles Cyc0. FIG. 8C shows the frequency distribution fmodule (:, CCAPth) of the number of charge / discharge cycles when the charge capacity CCAP of the assembled battery is the life threshold value CCAPth. 8A. The solid line in FIG. 8A is a line connecting the charging capacity CCAP of the most frequent value, and the dotted line is a line connecting the value of about 3σ from the mode value.

  Since the frequency is uniquely determined if the charge / discharge cycle number Cyc and the charge capacity CCAP are determined, the frequency at which the charge capacity becomes the life threshold value CCAPth at the charge / discharge cycle number Cyc0 in FIG. In c), when the charge capacity is the life threshold value CCPth, the frequency at which the charge / discharge cycle number becomes the charge / discharge cycle number Cyc0 is the same (the filled portion in the bar graph).

  The life distribution deriving unit 105 calculates the charge capacity as shown in FIG. 8B from the statistical assembled battery deterioration characteristic 206 as shown in FIG. 8A for each charge / discharge cycle number and the life threshold value CCAPth. The frequency f (Cyc, CCAPth) is taken out. Thereby, the lifetime distribution deriving unit 105 can derive the lifetime distribution life (:) of the assembled battery, which is a frequency distribution of the number of charge / discharge cycles when the charge capacity becomes the lifetime threshold value CCAPth. The life distribution life (:) is the same as the cross-section fmodule (:, CCAPth) when the charge capacity CCAP = lifetime threshold CCAPth in the charge capacity frequency distribution fmodule (:,:) as shown in FIG. It is. Therefore, the life distribution life (:) is life (:) = fmodule (:, CCAPth).

  Here, if the lifetime threshold value CCAPth is the lifetime capacity of the product, it is possible to grasp the distribution of the number of charge / discharge cycles in which the assembled battery reaches the lifetime, and the lifetime of the product can be estimated at the design stage. The life distribution life (:) may be normalized if necessary.

FIG. 9 is a flowchart for explaining the operation of the design apparatus of the present embodiment.
First, the statistical cell deterioration characteristic deriving unit 102 acquires a plurality of cell deterioration characteristics 201 from the storage unit 101, derives a statistical cell deterioration characteristic 204 based on the acquired plurality of cell deterioration characteristics 201, and performs statistical analysis. It outputs to the assembled battery deterioration characteristic deriving unit 104 (step S901).
In addition, the calculation procedure deriving unit 103 acquires the connection structure information 202 from the storage unit 101 and derives the calculation procedure x_order based on the acquired connection structure information 202. Then, the calculation procedure deriving unit 103 outputs calculation procedure information 205 indicating the derived calculation procedure x_order to the statistical assembled battery deterioration characteristic deriving unit 104 (step S902).
The statistical assembled battery deterioration characteristic deriving unit 104 receives the statistical cell deterioration characteristic 204 and the calculation procedure information 205 output in steps S901 and S902, respectively. The statistical assembled battery deterioration characteristic deriving unit 104 derives the statistical assembled battery deterioration characteristic 206 from the received statistical cell deterioration characteristic 204 according to the calculation procedure x_order indicated by the calculation procedure information 205 and outputs it to the life distribution deriving unit 105 ( Step S903).
The life distribution deriving unit 105 receives the statistical assembled battery deterioration characteristic 206 and acquires the life threshold information 203 from the storage unit 101. The life distribution deriving unit 105 is a frequency distribution of the number of charge / discharge cycles when the deterioration scale is the life threshold CCAPth indicated by the life threshold information 203 based on the statistical assembled battery deterioration characteristics 206 and the life threshold information 203. The life distribution life (:) of the assembled battery is derived. Then, the life distribution deriving unit 105 outputs the life distribution life (:) of the assembled battery (step S904).

As described above, according to the present embodiment, the statistical cell deterioration characteristic deriving unit 102 has a plurality of cell deterioration characteristics based on a plurality of cell deterioration characteristics that are respective deterioration characteristics of the plurality of storage battery cells used in the assembled battery. Statistical cell degradation characteristics, which are statistical data related to cell degradation characteristics, are derived. The calculation procedure deriving unit 103 derives a statistical assembled battery deterioration characteristic that is evaluation data for evaluating the deterioration characteristic of the assembled battery from the statistical cell deterioration characteristic based on the connection structure information indicating the connection structure between the plurality of storage battery cells. The calculation procedure for deriving is derived. The statistical assembled battery deterioration characteristic deriving unit 104 derives the statistical assembled battery deterioration characteristic from the statistical cell deterioration characteristic according to the calculation procedure. The life distribution deriving unit 105 evaluates the life of the assembled battery based on the statistical assembled battery deterioration characteristics.
Thus, from the deterioration characteristics of the assembled battery evaluated based on the plurality of cell deterioration characteristics that are the respective deterioration characteristics of the plurality of storage battery cells used in the assembled battery and the connection structure between the storage battery cells, Life is evaluated. Therefore, it is possible to accurately evaluate the life of the assembled battery including a plurality of storage battery cells.

(Second Embodiment)
In this embodiment, the reliability of the evaluation of the battery life by the method described in the first embodiment is verified.

  FIG. 10 is a diagram illustrating an example of cell deterioration characteristics according to the second embodiment of the present invention. In FIG. 10, the assembled battery is assumed to use ten 18650 type lithium ion battery cells as storage battery cells. The vertical axis represents the capacity maintenance rate SOH as a deterioration scale, and the horizontal axis represents the number of charge / discharge cycles as a life factor scale.

  In FIG. 10, the cell deterioration characteristic 11 shows the deterioration characteristic of the storage battery cell whose progress of deterioration is the slowest. The cell deterioration characteristic 12 indicates an average of deterioration characteristics of all the storage battery cells (specifically, a correspondence relationship between the average value of the capacity maintenance rates SOH of all the storage battery cells and the number of charge / discharge cycles). The cell deterioration characteristic 13 indicates the deterioration characteristic of the storage battery cell that progresses most rapidly. When the number of charge / discharge cycles is 300 cycles, the capacity maintenance rate SOH of the storage battery cell with the slowest progress of deterioration is about 0.7 of the best value, and the capacity maintenance rate SOH of the storage battery cell with the fastest progress of deterioration is the worst. The value is about 0.3. Further, the average value of the capacity retention rate SOH monotonously decreases as the number of charge / discharge cycles increases.

  FIG. 11 is a diagram for explaining the life of an assembled battery in which 200 storage battery cells having cell deterioration characteristics as shown in FIG. 10 are connected in series. In the example of FIG. 11, the life distribution 21 (solid line) of the assembled battery derived by using the method described in the first embodiment and the life distribution 22 (broken line) of the storage battery cells are shown. A life distribution 23 (dotted line) shown so as to overlap with the battery life distribution 21 of the battery pack is a battery life distribution obtained by the Monte Carlo method. Comparing the life distributions 21 and 23, the shapes of the distributions are almost equal, indicating that the method described in the first embodiment is highly reliable.

  The life distribution 22 of the storage battery cell is a cross section of the capacity retention rate SOH = 0.5 in FIG. The life distribution 22 of the storage battery cell is a wide distribution having a range in which the number of charge / discharge cycles ranges from 150 cycles to 600 cycles or more. On the other hand, the life distribution 21 of the assembled battery has a fairly narrow distribution in which the average value of the number of charge / discharge cycles is 140 cycles and does not exceed 200 cycles at most. This is because, in a configuration in which 200 battery cells are connected in series, the minimum value operator is repeatedly applied 199 times when deriving the life distribution, so the life distribution of the assembled battery is the life of the battery cell. This is because it tends to be biased to the minimum value of the distribution.

  As a result, for example, even if a storage battery cell with a probability that the life of the storage battery cell exceeds 400 cycles with a probability of 50% or more is used, in the assembled battery in which a large number of storage battery cells are connected in series, the life of the assembled battery is It shows less than 200 cycles. This shows a tendency for the life of the assembled battery to be shorter than the life of the storage battery cell, which is consistent with the actual result.

  Therefore, in the method described in the first embodiment, it is possible to evaluate the life of the assembled battery that could not be quantitatively evaluated so far, and it is possible to quantitatively predict the product life before designing. It becomes.

Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.
For example, in the above-described embodiment, various information necessary for the design of the power storage device is stored in the storage unit 101. However, part or all of the information is transmitted from another device via the network. It may be acquired or may be input from a user who uses the design apparatus.

DESCRIPTION OF SYMBOLS 100 Design apparatus 101 Memory | storage part 102 Statistical cell deterioration characteristic deriving part 103 Operation procedure deriving part 104 Statistical assembled battery deterioration characteristic deriving part 105 Life distribution deriving part

Claims (11)

Statistical cell degradation characteristics for deriving statistical cell degradation characteristics, which are statistical data related to the plurality of cell degradation characteristics, based on a plurality of cell degradation characteristics that are respective degradation characteristics of the plurality of storage battery cells used in the assembled battery A derivation unit;
An operation for deriving a statistical assembled battery deterioration characteristic that is evaluation data for evaluating the deterioration characteristic of the assembled battery from the statistical cell deterioration characteristic based on connection structure information indicating a connection structure between the plurality of storage battery cells A calculation procedure deriving unit for deriving the procedure;
A statistical assembled battery deterioration characteristic deriving unit for deriving the statistical assembled battery deterioration characteristic from the statistical cell deterioration characteristic according to the calculation procedure;
A design apparatus comprising: a life evaluation unit that evaluates a life of the assembled battery based on the statistical assembled battery deterioration characteristic. The cell deterioration characteristic indicates a correspondence relationship between a life factor scale that is a value related to a factor affecting the deterioration of the storage battery cell and a deterioration scale that is a value related to the degree of deterioration of the storage battery cell,
The statistical cell degradation characteristic deriving unit derives, as the statistical cell degradation characteristic, data indicating a frequency distribution of the degradation scale for each of the life factor scales in the plurality of cell degradation characteristics,
The statistical battery pack deterioration characteristic deriving unit obtains data indicating a distribution obtained by correcting the frequency distribution of the deterioration scale corresponding to the life factor scale according to the calculation procedure for each of the life factor scales. The design apparatus according to claim 1, derived as   The design apparatus according to claim 2, wherein the life evaluation unit outputs a frequency distribution of the life factor scale when the deterioration scale is a threshold value as an evaluation result of evaluating the life of the assembled battery. The calculation procedure derivation unit derives, as the calculation procedure, an operator corresponding to each connection relationship between the plurality of storage battery cells and an operation order to apply the operator.
The statistical assembled battery deterioration characteristic deriving unit is a total random variable obtained by applying the operators in the calculation order to random variables according to the frequency distribution of the deterioration scale corresponding to the life factor scale for each life factor scale. The design apparatus according to claim 2, wherein a distribution according to is derived as the statistical battery pack deterioration characteristic.   The calculation procedure deriving unit derives an average value operator as the operator when the connection relation indicates parallel, and derives an average value operator as the operator, and the deterioration measure is not normalized. The design apparatus according to claim 4, wherein a sum operator is derived.   The design device according to claim 4 or 5, wherein the calculation procedure deriving unit derives a minimum value operator as the operator when the storage battery cells are connected in series.   The design apparatus according to claim 4, wherein the calculation procedure deriving unit derives the operator as a binary operator.   The design apparatus according to claim 7, wherein the calculation procedure deriving unit represents the calculation order in a topological order.   The design apparatus according to claim 4, wherein the calculation procedure deriving unit represents the calculation order by an operation tree. Based on a plurality of cell deterioration characteristics that are respective deterioration characteristics of a plurality of storage battery cells used in the assembled battery, a statistical cell deterioration characteristic that is statistical data related to the plurality of cell deterioration characteristics is derived,
An operation for deriving a statistical assembled battery deterioration characteristic that is evaluation data for evaluating the deterioration characteristic of the assembled battery from the statistical cell deterioration characteristic based on connection structure information indicating a connection structure between the plurality of storage battery cells Deriving the procedure
Deriving the statistical battery pack deterioration characteristic from the statistical cell deterioration characteristic according to the calculation procedure,
The design method which evaluates the lifetime of the said assembled battery based on the said statistical assembled battery deterioration characteristic. A function of deriving statistical cell deterioration characteristics, which are statistical data related to the plurality of cell deterioration characteristics, based on a plurality of cell deterioration characteristics that are respective deterioration characteristics of the plurality of storage battery cells used in the assembled battery;
An operation for deriving a statistical assembled battery deterioration characteristic that is evaluation data for evaluating the deterioration characteristic of the assembled battery from the statistical cell deterioration characteristic based on connection structure information indicating a connection structure between the plurality of storage battery cells The ability to derive procedures;
A function of deriving the statistical assembled battery deterioration characteristic from the statistical cell deterioration characteristic according to the calculation procedure;
The program for making a computer implement | achieve the function which evaluates the lifetime of the said assembled battery based on the said statistical assembled battery deterioration characteristic.

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