Battery cell arrangement method

Abstract

To provide a battery cell arrangement method capable of suppressing deterioration of a battery cell.SOLUTION: A battery cell arrangement method estimates the deterioration gradient of each battery cell on the basis of the basis weight of negative electrodes of multiple battery cells, information on a negative electrode active material, and information on an electrolyte, and determines the arrangement of each battery cell within the case such that battery cells with a large deterioration gradient are arranged in positions within the case where the temperature is likely to be lower.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to a method for arranging battery cells. [Background technology]

[0002] Patent Document 1 discloses a method of ranking battery cells based on their power storage capacity, and arranging battery cells with larger power storage capacities in peripheral areas that are more likely to be cooled. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-231911 A Summary of the Invention [Problem to be solved by the invention]

[0004] The rate of deterioration varies depending on the battery cell, and the rate of deterioration also changes depending on the temperature difference between the battery cells. Therefore, the technology disclosed in Patent Document 1 does not take into consideration the deterioration of the battery cells, so there is a possibility that the battery cells may deteriorate easily.

[0005] The present disclosure has been made in consideration of the above, and has an object to provide a battery cell arrangement method that can suppress deterioration of the battery cells. [Means for solving the problem]

[0006] The battery cell arrangement method according to the present disclosure estimates the deterioration gradient of each battery cell based on the negative electrode basis weight of a plurality of battery cells, information on the negative electrode active material, and information on the electrolyte, and determines the arrangement of each battery cell within a case such that a battery cell with a large deterioration gradient is arranged in a position within the case where the temperature is likely to be low. Effect of the Invention

[0007] According to the present disclosure, battery cells with a large tendency to deteriorate are disposed in positions within the case where the temperature is likely to be low, thereby making it possible to suppress deterioration of the battery cells. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of an information processing device that executes a battery cell arrangement method according to an embodiment. [Diagram 2] FIG. 2 is a graph showing the relationship between the negative electrode area weight of a battery cell and capacity degradation. [Diagram 3] FIG. 3 is a schematic diagram showing the relationship between the negative electrode weight of a battery cell and capacity degradation. [Figure 4] FIG. 4 is a schematic diagram for explaining the temperature distribution inside the battery cell case. [Diagram 5] FIG. 5 is a schematic diagram for explaining a method of arranging the battery cells according to the embodiment. [Figure 6] FIG. 6 is a flowchart showing the flow of the battery cell arrangement method according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A battery cell arrangement method according to an embodiment of the present disclosure will be described with reference to the drawings. Note that components in the following embodiments include those that are easily replaceable by a person skilled in the art, or those that are substantially the same.

[0010] The battery cell arrangement method according to the embodiment is a method for arranging battery cells in a battery pack case to be mounted on, for example, a vehicle. Examples of the vehicle include a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a battery electric vehicle (BEV).

[0011] (Information processing device) An example of the configuration of an information processing device that executes a battery cell arrangement method according to an embodiment will be described with reference to Fig. 1. This information processing device is realized by a general-purpose computer such as a workstation or a personal computer.

[0012] 1, the information processing device 1 includes a deterioration gradient estimation unit 11 and an arrangement determination unit 12. The deterioration gradient estimation unit 11 and the arrangement determination unit 12 are realized, for example, by the functions of a calculation device (calculation unit) included in the information processing device 1. The calculation device includes a processor including, for example, a CPU (Central Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field-Programmable Gate Array), a GPU (Graphics Processing Unit), etc., and a memory (main storage unit) including a RAM (Random Access Memory), a ROM (Read Only Memory), etc.

[0013] The deterioration gradient estimation unit 11 estimates the deterioration gradient of a plurality of battery cells housed in a case. Specifically, the deterioration gradient estimation unit 11 estimates the deterioration gradient of each battery cell based on the negative electrode weight of the battery cell, information on the negative electrode active material of the battery cell, and information on the electrolyte of the battery cell.

[0014] Here, the "negative electrode coating weight" specifically refers to the mass per unit area of ​​the negative electrode active material layer applied to the substrate. Also, the "information about the negative electrode active material" specifically refers to the negative electrode active material BET, which indicates the specific surface area of ​​the negative electrode active material by the BET method. Also, the "information about the electrolyte of the battery cell" specifically refers to the amount of electrolyte LiBOB, which indicates the amount of LiBOB (lithium bis(oxalato)borate) in the electrolyte.

[0015] Also, for example, as shown in FIG. 2, there is a positive correlation between the negative electrode basis weight and the degradation slope (capacity degradation of the battery cell). Therefore, as shown in FIG. 3, a battery cell with a large negative electrode basis weight (battery cell A) exhibits a high rate of capacity degradation, and conversely, a battery cell with a small negative electrode basis weight (battery cell B) exhibits a low rate of capacity degradation. Similarly, there is a positive correlation between the negative electrode active material BET and the degradation slope, and there is a negative correlation with the degradation slope of the amount of electrolyte LiBOB. Therefore, it is possible to estimate the degradation slope of each battery cell based on the negative electrode basis weight, the negative electrode active material BET, and the amount of electrolyte LiBOB.

[0016] The negative electrode weight, the negative electrode active material BET, and the amount of electrolyte LiBOB each have a different degree of influence on the degradation slope. Therefore, the degradation slope estimation unit 11 multiplies the negative electrode weight, the negative electrode active material BET, and the amount of electrolyte LiBOB by the degradation slope influence degree obtained in advance by an experiment or the like. Then, the degradation slope estimation unit 11 ranks the multiple battery cells housed in the case based on the degradation slope corresponding to the negative electrode weight, the negative electrode active material BET, and the amount of electrolyte LiBOB that reflect the degradation slope influence degree. In other words, this "ranking" refers to identifying the magnitude of the degradation slope of each battery cell.

[0017] Specifically, the deterioration slope estimation unit 11 multiplies the deviation width of the negative electrode basis weight from the center value (reference value) by the deterioration slope influence degree X. Specifically, the deterioration slope estimation unit 11 multiplies the deviation width of the negative electrode active material BET from the center value (reference value) by the deterioration slope influence degree Y. Specifically, the deterioration slope estimation unit 11 multiplies the deviation width of the electrolyte LiBOB amount from the center value (reference value) by the deterioration slope influence degree Z. Then, the deterioration slope estimation unit 11 estimates the deterioration slope corresponding to the largest value among the negative electrode basis weight, the negative electrode active material BET, and the electrolyte LiBOB amount reflecting the deterioration slope influence degrees X, Y, and X as the deterioration slope of each battery cell.

[0018] The placement determination unit 12 determines the placement of each battery cell in the case based on the degradation gradient estimated by the degradation gradient estimation unit 11. That is, the placement determination unit 12 determines the placement of each battery cell in the case such that a battery cell with a large degradation gradient is placed in a position in the case where the temperature is likely to be low. The placement determination unit 12 also determines the placement of each battery cell in the case such that a battery cell with a small degradation gradient is placed in a position in the case where the temperature is likely to be high.

[0019] In a case that houses multiple battery cells, there are positions that tend to get cold and positions that tend to get warm, as shown in Fig. 4. Therefore, the placement determination unit 12 determines a position in the case where the temperature is likely to be low (e.g., the back side of the page) as a position for placing a battery cell with a large degradation gradient (battery cell A), as shown in Fig. 5. The placement determination unit 12 also determines a position in the case where the temperature is likely to be high (e.g., the front side of the page) as a position for placing a battery cell with a small degradation gradient (battery cell B).

[0020] As a result, the battery cell with a greater degradation gradient is arranged in a position where the temperature inside the case is lower (easier to become lower), and the battery cell with a smaller degradation gradient is arranged in a position where the temperature inside the case is higher (easier to become higher). As a result, degradation of the battery cells due to the temperature difference inside the case is suppressed.

[0021] (Battery cell arrangement) The flow of the battery cell arrangement method according to the embodiment will be described with reference to FIG.

[0022] First, the deterioration gradient estimation unit 11 estimates the deterioration gradient of each battery cell housed in the case (step S1). The deterioration gradient estimation unit 11 estimates the deterioration gradient of each battery cell using values ​​calculated as in the following (1) to (3).

[0023] (1) Deviation from the center value of negative electrode weight × Degree of influence of deterioration gradient X (2) Deviation from the center value of the negative electrode active material BET × Degradation slope influence degree Y (3) Deviation from the center value of the amount of electrolyte LiBOB × Degradation slope influence degree Z

[0024] Next, the placement determination unit 12 determines the placement of each battery cell based on the deterioration gradient of each battery cell (step S2). As a result, each battery cell is placed as shown in (1) or (2) below.

[0025] (1) Battery cells that are more susceptible to deterioration are placed in positions within the case that have lower temperatures (are more likely to become colder). (2) Battery cells with a small deterioration tendency are placed in positions within the case that are higher in temperature (or more likely to become hot).

[0026] According to the battery cell arrangement method of the embodiment described above, battery cells with a large degradation tendency are arranged in positions within the case where the temperature is likely to be low, thereby suppressing degradation of the battery cells.

[0027] Further advantages and modifications may readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0028] 1. Information processing device 11 Deterioration gradient estimation section 12 Placement determination section

Claims

[Claim 1] estimating a deterioration gradient for each of the battery cells based on the negative electrode area weight of the plurality of battery cells, information on the negative electrode active material, and information on the electrolyte; determining an arrangement of each of the battery cells within the case such that the battery cell having a large deterioration gradient is arranged at a position within the case where the temperature is likely to be low; How the battery cells are arranged.

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