Battery cell grouping method, battery cell arrangement method and system, battery pack and vehicle

Abstract

The invention discloses a battery cell grouping method, a battery cell arrangement method and system, a battery pack and a vehicle. The battery aging capability can be remarkably improved under the condition of not increasing too much research and development cost. The battery cell grouping method comprises the following steps: acquiring a designed battery cell capacity range of the plurality of battery cells; calculating the designed battery cell capacity range based on a normal distribution rule, and dividing the designed battery cell capacity range into N continuous sub-ranges, namely a first sub-range with the largest battery cell capacity range, a second sub-range with the second largest battery cell capacity range, and an Nth sub-range with the smallest battery cell capacity range, N being an integer greater than 1; and acquiring the actual battery cell capacity of each battery cell, and grouping each battery cell into the corresponding sub-range based on the corresponding relationship between the actual battery cell capacity and the N sub-ranges.

Description

Technical Field

[0001] The present disclosure relates to a method for grouping battery cells, a method and system for arranging battery cells, a battery pack, and a vehicle, belonging to the technical fields of batteries and vehicles. Background Art

[0002] In fields such as new energy vehicles and energy storage systems, as a core component for energy storage, the performance of a battery module directly affects the endurance and service life of the device. The traditional assembly method of battery modules usually adopts random arrangement of battery cells, that is, battery cells with different characteristics such as capacity and internal resistance are assembled together without distinction. Although this method simplifies the production process and reduces the initial cost, the performance differences between battery cells bring many challenges to the long-term operation of the battery module. As the basic unit of the battery module, the individual performance of the battery cell directly affects the overall performance of the entire module. Especially during long-term charge and discharge cycles, the aging rate and capacity attenuation of the battery cell become key indicators for measuring the life of the battery module.

[0003] However, the method of randomly assembling battery cells exposes a series of technical problems, seriously restricting the aging ability and improvement of the overall performance of the battery module. First of all, the problem of capacity mismatch between battery cells is particularly prominent. Due to the inevitable capacity differences in the manufacturing process of battery cells, random assembly results in the battery cell with the smallest capacity in the module becoming the short board that limits the overall capacity of the module. During the cyclic charge and discharge process, this short-board battery cell will reach its performance limit faster, thus accelerating the aging process of the entire module. Secondly, thermal management becomes another major problem. Battery cells generate heat during operation, and random arrangement makes the thermal distribution inside the module extremely uneven. Some battery cells may age faster due to overheating, which not only affects the aging ability of the entire module, but also further expands the performance differences between battery cells, and even causes safety problems, affecting the driving experience. Summary of the Invention

[0004] To solve the above technical problems, the present disclosure proposes a method for grouping battery cells, a method and system for arranging battery cells, a battery pack, and a vehicle, which can significantly improve the battery aging ability without increasing too much R & D cost.

[0005] The first aspect of the present disclosure provides a method for grouping battery cells, which is used for grouping a plurality of battery cells with a predetermined number, and is characterized in that the method for grouping battery cells includes:

[0006] Obtaining the designed battery cell capacity range of the plurality of battery cells;

[0007] Calculate the designed cell capacity range based on the normal distribution rule, and divide the designed cell capacity range into N consecutive sub-ranges, that is, the first sub-range with the largest cell capacity range, the second sub-range with the second largest cell capacity range, until the Nth sub-range with the smallest cell capacity range, where N is an integer greater than 1; and

[0008] Obtain the actual cell capacity of each cell, and group each cell into the corresponding sub-range based on the correspondence between the actual cell capacity and the N sub-ranges.

[0009] Using the cell grouping method of the first aspect, by obtaining the designed cell capacity range of the cells and dividing it based on the normal distribution rule, the cell capacity characteristics within each sub-range can be made similar, thereby improving the accuracy of grouping. After cell grouping, the requirements of each module in the battery system can be more precisely matched. By combining cells with similar capacities together, the capacity difference within the battery system can be reduced, thereby enhancing the stability and consistency of the entire system, extending the battery life, improving the safety and reliability of the battery system, enhancing the overall performance of the battery system, and enhancing the battery aging ability. In addition, this grouping method provides a clear basis for the screening and assembly of cells, making the production process more standardized and efficient. On the production line, workers can quickly assign cells to the corresponding sub-ranges according to their actual capacities, reducing the time and workload of screening and classification. At the same time, when assembling the battery module, since the cells have been grouped according to capacity, the assembly process is more convenient, improving the production efficiency.

[0010] Preferably, in the cell grouping method of the first aspect above, it includes: configuring N cell placement parts such that the N cell placement parts are configured in a one-to-one correspondence with the N sub-ranges, and placing the cells grouped into each sub-range in the corresponding cell placement part.

[0011] Using the cell grouping method with the above configuration, by grouping cells according to a preset sub-range and placing them in corresponding cell placement parts such as shelves, the orderly storage of cells in the warehouse or on the production line can be ensured. This orderliness helps to quickly locate and retrieve cells, improving the efficiency of storage and management; the one-to-one correspondence between cell grouping and shelf positions simplifies the processes of cell warehousing, outbound, and inventory taking. Staff can quickly find the corresponding shelf positions just based on the parameter range of the cells, reducing the time for searching and handling, and enhancing the efficiency of cell storage and management. Additionally, before assembling the battery module, it is necessary to match the cells according to their parameters. By grouping the cells according to a preset sub-range and placing them on the shelves, it is convenient for staff to quickly select the cells that meet the requirements for matching, improving the assembly efficiency; the orderly storage and grouping help to reduce the error during the cell matching process. Staff can more easily check the parameters of the cells to ensure that the cell performance in each module is similar, thereby improving the overall performance of the battery pack.

[0012] Preferably, in the cell grouping method of the first aspect above, it includes: dividing the designed cell capacity range into multiple grades, and performing the calculation for the cell capacity range of each grade.

[0013] Using the cell grouping method with the above configuration can well adapt to the production capacity differences of different manufacturers. Even if there are differences in the production capacities of different manufacturers, resulting in different distribution ranges of cell capacities, however, by dividing the cell capacity range into multiple grades, it can better adapt to the production capacities of different manufacturers, making the cell grouping more flexible and reasonable.

[0014] The second aspect of the present disclosure provides a cell arrangement method for a battery module, including:

[0015] Based on the design information of the battery module, obtaining a first target arrangement position among the respective cell arrangement positions of the battery module, where, when the battery module is working, the cell arranged at the first target arrangement position has the highest cell temperature or the highest cell extrusion pressure; and

[0016] Taking the cells grouped into the first sub-range among the N sub-ranges according to the first aspect as the first cells, and arranging the first cells at the first target arrangement position.

[0017] According to the battery cell arrangement method with the above configuration, the battery cell capacity sub-ranges are divided according to the normal distribution rule, and the battery cells in the first sub-range with the largest battery cell capacity range are arranged at the first target arrangement position where the temperature or extrusion pressure is the highest when the battery module is working. Thus, by using large-capacity battery cells that can withstand higher energy conversion loads, their performance degradation is relatively small under high temperature or high extrusion pressure, which helps to balance the performance of the entire battery module and improve the stability and consistency of the battery module output. In addition, by matching the advantages of large-capacity battery cells with the most challenging working position in the battery module, i.e., the first target arrangement position, under high temperature or high extrusion pressure environment, large-capacity battery cells can better maintain their working state by virtue of their own characteristics, enabling the capacity advantages of the battery cells to be fully exerted, thereby improving the overall energy output capacity and working efficiency of the battery module. In the battery module, although the aging speeds of battery cells at different positions may vary due to different working conditions, concentrating large-capacity battery cells at the first target arrangement position with harsh working conditions makes the aging speed of the battery cells at this position relatively closer to that of the battery cells at other positions. Because the performance degradation of large-capacity battery cells is relatively slow under high temperature or high pressure, this helps to reduce the inconsistency of the aging degree of the battery cells inside the entire battery module, extend the overall service life of the battery module, delay the aging process of the battery module as a whole, reduce the situation where the performance of the entire battery module deteriorates or fails due to premature aging of local battery cells, and improve the service life, reliability, and aging resistance of the battery module.

[0018] Preferably, in the battery cell arrangement method of the second aspect, it includes:

[0019] Based on the design information, each battery cell arrangement position of the battery module is divided to include the first target arrangement position, the second target arrangement position, the third target arrangement position up to the Nth target arrangement position. Among them, when the battery module is working, the battery cells arranged at the second target arrangement position have the second-highest battery cell temperature or the second-highest battery cell extrusion pressure, the battery cells arranged at the third target arrangement position have the third-highest battery cell temperature or the third-highest battery cell extrusion pressure, and successively, the battery cells arranged at the Nth target arrangement position have the lowest battery cell temperature or the lowest battery cell extrusion pressure, and

[0020] The battery cells in the first sub-range are used as the first battery cells and arranged at the first target arrangement position, the battery cells in the second sub-range are used as the second battery cells and arranged at the second target arrangement position, and successively, the battery cells in the Nth sub-range are used as the Nth battery cells and arranged at the Nth target arrangement position.

[0021] Using the battery cell layout method with the above configuration, according to the temperature or extrusion pressure conditions at each position of the battery module, different-capacity-range battery cells are accurately arranged at corresponding positions. The battery cells with larger capacities (the first battery cells in the first sub-range) are arranged at the first target positions with the highest temperature or extrusion pressure, which can better cope with high-temperature and high-extrusion working conditions, give full play to their large-capacity advantages, and maintain high performance. While the battery cells with relatively smaller capacities are arranged at positions with lower temperature or extrusion pressure. Overall, the optimal matching between the battery cell performance and the working environment is achieved, and the comprehensive performance of the battery module under various working conditions is improved. Since the working conditions of the battery cells at different positions are different, by arranging the battery cells in a graded manner according to conditions, each battery cell works in its adapted environment, reducing the impact of the sudden performance drop of individual battery cells in an unsuitable environment on the overall performance, ensuring that the battery module outputs more stably and evenly, and improving the performance consistency of the entire battery module. Arranging battery cells with different characteristics at adapted working positions avoids the acceleration of battery cells in overly harsh environments. Placing the large-capacity battery cells that can better withstand high temperature and high pressure at the corresponding high-temperature and high-pressure positions, their aging speed is relatively slowed down, thereby extending the service life of the entire battery module and reducing the difference in the aging degree between the battery cells at different positions. This helps to maintain the consistency of the battery cell performance inside the battery module, reduces the situation where the life of the entire module is affected by the excessive aging of individual battery cells, and further extends the service life of the battery module.

[0022] Preferably, in the battery cell layout method of the second aspect, it includes,

[0023] Select the first battery cell from the battery cells placed in the first battery cell placement part corresponding to the first sub-range, and arrange the first battery cell at the first target layout position;

[0024] Select the second battery cell from the battery cells placed in the second battery cell placement part corresponding to the second sub-range, and arrange the second battery cell at the second target layout position; and

[0025] Sequentially,

[0026] Select the Nth battery cell from the battery cells placed in the Nth battery cell placement part corresponding to the Nth sub-range, and arrange the Nth battery cell at the Nth target layout position.

[0027] Using the battery cell arrangement method with the above configuration, the battery cells are placed in the corresponding battery cell placement parts according to sub-ranges. It is like building an orderly warehousing system. During production, the battery cells can be directly selected from specific placement parts and arranged at the corresponding target positions, making the warehousing picking process clear and definite, improving the utilization rate of warehousing space and the efficiency of finding and extracting battery cells. For example, during large-scale production of battery modules, the staff can quickly locate the required battery cells, reducing the time waste of searching for battery cells and enhancing the overall production rhythm. This corresponding relationship of the battery cell arrangement method with the above configuration ensures that battery cells with different capacities can be accurately obtained on the production line. Each battery cell placement part is specifically set for battery cells in a specific sub-range, supplying suitable battery cells for different target arrangement positions and ensuring the smooth progress of the production process. For example, on an automated production line, the robotic arm can accurately grab battery cells from the corresponding placement part according to the preset program and place them at the designated positions, reducing production stagnation caused by incorrect battery cell supply.

[0028] Preferably, in the battery cell arrangement method of the second aspect, the first target arrangement position is the central position among all the battery cell arrangement positions, or the first target arrangement position is the arrangement position closest to the outlet of the cooling water pipe among all the battery cell arrangement positions.

[0029] Using the battery cell arrangement method with the above configuration, when the first target arrangement position is the central position, it can effectively improve the anti-aging ability of the battery module. The central position inside the battery module usually has relatively difficult heat dissipation and the temperature is prone to be on the high side. Placing the battery cells in the first sub-range at the central position, since the capacity of this part of the battery cells is relatively large, they can usually withstand a certain high-temperature environment, which can balance the temperature field inside the battery module to a certain extent, making the temperature distribution of the entire module more uniform, reducing problems such as battery performance decline and shortened lifespan caused by local overheating, and improving the overall stability and reliability of the battery module. In addition, during the operation of the battery module, the central position may bear a relatively large extrusion force or stress. An increase in the pressure of the battery cells will cause more electrolyte to be extruded from the battery cells after charging, reducing the actual active lithium available for charge and discharge, making the battery cells more prone to black spots and lithium deposition, resulting in rapid capacity decay. By placing the large-capacity battery cells at the central position, due to their higher energy storage capacity, during the charge and discharge process, the large-capacity battery cells can provide a more stable and lasting energy output, helping to balance the charge and discharge states of each battery cell in the module and reducing performance imbalance caused by capacity differences.

[0030] On the other hand, by using the battery cell arrangement method with the above configuration, considering the actual situation, due to the design of the cooling circuit, the highest battery cell position is not necessarily at the central position. For example, the inlet of the cooling water pipe is close to one section of the module, while the outlet is close to the other section. Therefore, in this case, the first target arrangement position is the arrangement position closest to the outlet of the cooling water pipe. The coolant temperature at the outlet of the cooling water pipe is relatively high, and the cooling capacity is relatively weak. Arranging the battery cells in the first sub-range at the position closest to the outlet of the cooling water pipe, since these battery cells have a large capacity and good performance, and have relatively strong tolerance to temperature, they can still maintain a good working state under relatively poor cooling conditions, thereby making more reasonable use of the cooling resources and improving the overall efficiency of the cooling system. Moreover, in the battery module, the position close to the outlet of the cooling water pipe may be a key area for temperature control. If the battery cells at this position have poor performance, they are easily affected by high temperature and malfunction, which will in turn affect the performance of the entire battery module. Arranging the battery cells in the first sub-range here can use their good performance to resist the possible high temperature risk, play a role in protecting the battery cells at the key position, and enhance the reliability of the battery module. From the inlet to the outlet of the cooling water pipe, the coolant temperature gradually increases, and the temperature of the battery module will also show a certain gradient distribution. Arranging the battery cells in the first sub-range near the outlet can optimize the temperature distribution of the entire battery module according to the relationship between the battery cell performance and the temperature gradient, make the temperature difference between the battery cells more reasonable, reduce the problem of uneven battery performance caused by too large temperature difference, and improve the overall performance and life of the battery module.

[0031] The third aspect of the present disclosure provides a battery cell arrangement system, including:

[0032] N battery cell placement parts, the N battery cell placement parts corresponding one by one to the N sub-ranges described in claim 1, and

[0033] An automatic transportation part, which automatically transports the battery cells to the corresponding battery cell placement parts based on the actual battery cell capacity of the produced battery cells.

[0034] Using the battery cell arrangement system with the above configuration, the automatic transportation unit automatically transports the battery cells to the corresponding battery cell placement unit according to the actual capacity of the battery cells, realizing the automated process of battery cells from production offline to storage. This greatly reduces the workload of manual sorting and handling, improves the efficiency of battery cell storage, reduces the errors that may be caused by manual operations, and makes the entire battery cell storage link smoother and more efficient. During large-scale battery cell production, it can quickly respond to the production rhythm and timely classify and store the produced battery cells. For example, on a high-speed production line, the automatic transportation unit can process the produced battery cells in real time to ensure that the production progress is not affected by delays in the storage link, improving the operating efficiency of the entire production system. Automatically and accurately classifying the battery cells into the corresponding placement units according to the capacity range helps to ensure the capacity consistency of the battery cells in each placement unit. This is crucial for the selection of battery cells during subsequent battery module production, can reduce the problem of unstable battery module performance caused by individual differences in battery cells, and improves the overall quality of the battery module. The automated transportation and precise placement correspondence effectively avoid the mixing phenomenon of battery cells with different capacity ranges. As mentioned in the background art, the mixing of battery cells may cause a serious decline in the performance of the battery module. The system in the third aspect reduces this risk from the source through strict classified storage, ensuring the aging ability of the battery cells and subsequent battery products. Finally, when producing battery modules, the required battery cells within the corresponding capacity range can be directly obtained from the corresponding battery cell placement unit, realizing the efficient docking between the warehousing and production links. This orderly storage method makes it more convenient to retrieve battery cells on the production line, reduces the production waiting time, improves the production efficiency, and is also conducive to the formulation and implementation of production plans.

[0035] The fourth aspect of the present disclosure provides a battery pack, which has more than one battery module. Among them, the battery cells in the battery module are arranged according to the battery cell arrangement method described in the second aspect.

[0036] The fifth aspect of the present disclosure provides a vehicle, which is equipped with the battery pack described in the fourth aspect.

[0037] For the battery pack in the fourth aspect and the vehicle in the fifth aspect, due to the adoption of the battery cell arrangement method described in the second aspect, the same technical effects as mentioned above can be achieved. Description of the Drawings

[0038] The drawings are used to better understand the present invention and do not constitute an improper limitation to the present invention. Among them:

[0039] Figure 1 is a schematic block diagram of the battery cell grouping method according to the first embodiment of the present disclosure;

[0040] Figure 2 is a further schematic block diagram of the battery cell grouping method according to the first embodiment of the present disclosure;

[0041] Figure 3 is a schematic block diagram of a core arrangement method for a battery module according to the second embodiment of the present disclosure;

[0042] Figure 4 is the change of the capacity retention rate of a battery in the prior art with the number of cycles at different temperatures; and

[0043] Figure 5 is the change of the capacity retention rate of a battery with the number of cycles at different temperatures when the first embodiment and the second embodiment of the present disclosure are applied. Detailed implementation manners

[0044] Hereinafter, the technical solutions of the present invention will be more clearly described by describing the detailed implementation manners of the present invention with reference to the accompanying drawings.

[0045] If there is no special description, all the embodiments and optional embodiments of the present disclosure can be combined with each other to form a new technical solution. If there is no special description, all the technical features and optional technical features of the present invention can be combined with each other to form a new technical solution.

[0046] If there is no special description, all the steps of the present invention can be carried out in sequence or randomly, and preferably in sequence. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) carried out in sequence, or may include steps (b) and (a) carried out in sequence. For example, it is mentioned that the method may further include step (c), which means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0047] <First Embodiment>

[0048] Figure 1 shows a schematic block diagram of a core grouping method according to the first embodiment of the present disclosure, for grouping a plurality of cores with a predetermined number. As Figure 1 shown, the core grouping method of the embodiment includes steps S101 to S103.

[0049] In step S101, obtain the designed core capacity range of the plurality of cores.

[0050] During the large-scale production process of battery cells, due to the influence of factors such as production processes and raw materials, the actual capacity of the battery cells will fluctuate within a certain range. The designed battery cell capacity range is the theoretical capacity interval specified during product design, and battery cells within this capacity range are generally regarded as qualified products. Since the battery cell capacity regarded as a qualified product only needs to be within the designed battery cell capacity range, there are often differences between the actual battery cell capacities of the finished battery cells. The inventor of this disclosure noticed the impact of this difference on the performance of the battery module. Starting from the designed battery cell capacity range, the battery cells are grouped according to their capacities to minimize the performance differences between the battery cells inside the module, thereby improving the overall performance and aging ability of the module.

[0051] As Figure 1 shown, in step S102, based on the normal distribution rule, the designed battery cell capacity range is calculated, and the designed battery cell capacity range is divided into N consecutive sub-ranges, that is, the first sub-range with the largest battery cell capacity range, the second sub-range with the second largest battery cell capacity range, until the Nth sub-range with the smallest battery cell capacity range, where N is an integer greater than 1.

[0052] In actual production, the battery cell capacities usually show a pattern similar to the normal distribution. In step S102, dividing the capacity sub-ranges based on the normal distribution rule can more accurately classify battery cells with different capacities, making the battery cell capacities within the same sub-range closer to each other. Compared with simple average division and other methods, this grouping is more refined and more in line with the actual distribution of battery cell capacities. According to different application scenarios and product requirements, the number of sub-ranges N divided can be flexibly adjusted. For example, for high-end applications with extremely high requirements for battery performance consistency, the value of N can be increased to achieve more detailed grouping, providing the possibility for subsequent selection of the most matching battery cell combinations; while for some applications that are more sensitive to cost and have relatively lower performance requirements, the value of N can be appropriately reduced to reduce costs and production complexity while ensuring certain performance.

[0053] In step S102, through the division based on the normal distribution, the capacity distribution of each battery cell in the battery module can be made more reasonable, reducing the imbalance phenomenon during the charge and discharge process of the battery module caused by excessive differences in battery cell capacities. The performance of each battery cell during the charge and discharge process is more consistent, thereby improving the overall performance of the battery module, such as charge and discharge efficiency, cycle life, etc. Moreover, since the battery cell capacity characteristics within the same sub-range are similar, when the battery module is working, parameters such as their voltage changes and temperature rises will also be relatively close, which helps to reduce the stress and thermal non-uniformity inside the battery module, reduce the occurrence probability of problems such as local overheating, overcharging, and over-discharging, and thus enhance the stability and reliability of the battery module and improve its aging ability.

[0054] As Figure 1As shown, in step S103, the actual cell capacity of each cell is obtained, and based on the correspondence between the actual cell capacity and the N sub-ranges, each cell is grouped into the corresponding sub-range.

[0055] In step S103, by matching the actual cell capacity of the cell with a preset sub-range, it can be ensured that each cell is accurately assigned to a sub-range with similar performance. This precise matching helps to reduce the performance differences between the cells inside the module, making the cells that ultimately form the battery module more matched in capacity and improving the overall performance and stability of the module. During the charge and discharge process of the battery module, each cell can perform charge transfer and energy storage and release more evenly, reducing the problem of asynchronous charge and discharge progress caused by the difference in cell capacity, thereby improving the consistency of the overall performance of the battery module. Since the grouped cells are more similar in capacity characteristics, they work together better in the battery module. Throughout the service life cycle of the entire battery module, the performance of each cell can be more fully utilized, avoiding the situation where the overall efficiency is dragged down due to the mismatch of the capacity of individual cells, and optimizing key performance indicators such as the energy density and endurance of the battery module.

[0056] Figure 2 shows a further schematic block diagram of the cell grouping method according to an embodiment of the present disclosure. As Figure 2 shown, in addition to Figure 1 the steps S101 to S103 shown, the cell grouping method of this embodiment may further include step S104 and step S105.

[0057] In step S104, N cell placement parts are configured so that the N cell placement parts are configured in a one-to-one correspondence with the N sub-ranges. In step S105, the cells grouped into each sub-range are placed in the corresponding cell placement part.

[0058] The battery cells are grouped according to the further adopted steps S104 and S105. By grouping the battery cells according to a preset sub-range and placing them in corresponding battery cell placement parts such as shelves, the orderly storage of the battery cells in the warehouse or on the production line can be ensured. This orderliness helps to quickly locate and retrieve the battery cells, improving the efficiency of storage and management; the one-to-one correspondence between the battery cell grouping and the shelf positions simplifies the processes of warehousing, outbound and inventory taking of the battery cells. The staff can quickly find the corresponding shelf positions only according to the parameter range of the battery cells, reducing the time for searching and handling and enhancing the efficiency of battery cell storage and management. In addition, before assembling the battery modules, it is necessary to match the battery cells according to their parameters. By grouping the battery cells according to a preset sub-range and placing them on the shelves, it is convenient for the staff to quickly select the battery cells that meet the requirements for matching, improving the assembly efficiency; the orderly storage and grouping help to reduce the error in the process of matching the battery cells. The staff can more easily check the parameters of the battery cells to ensure that the performance of the battery cells in each module is similar, thereby improving the overall performance of the battery pack.

[0059] Next, the above-described battery cell grouping method will be specifically described by way of examples.

[0060] Assume that the designed battery cell capacity range of each battery cell required for a certain battery module is 79.1 Ah - 84.6 Ah; and the quality control range is 4σ.

[0061] If the battery cells are not grouped but randomly placed and grouped together and randomly assembled into the battery modules, at this time, when a battery cell with a smaller capacity is assembled near the middle position of the battery module (this is a high-probability event), the capacity of the battery after aging to 80% is 79.1 x 80% = 63.28 Ah; and the number of charge-discharge cycles of the battery is 3000 cycles (assuming that the temperature in the middle of the module is 10 degrees Celsius higher than the surrounding temperature). Specifically, please refer to the appendix Figure 4 。

[0062] In contrast, in this embodiment, by adopting the above-described battery cell grouping method, the number of charge-discharge cycles of the battery can be increased to approximately 3500 cycles, that is, the aging ability is increased by approximately 10%. This will be described in the subsequent second embodiment.

[0063] Specifically, take the example that there are a total of 4 battery modules in the battery pack body, and each battery module contains 25 battery cells.

[0064] First, obtain the designed cell capacity range, i.e., 79.1 Ah - 84.6 Ah. Then, calculate the designed cell capacity range based on the normal distribution rule. The cell capacity distribution follows a normal distribution. For the designed cell capacity range of 79.1 - 84.6 Ah, the cells follow the following normal distribution: mean = (84.6 + 79.1) / 2 = 81.85; and standard deviation = (84.6 - 79.1) / 4 = 1.375.

[0065] For this example, set the grouping target to be divided into 13 groups, i.e., 13 sub - ranges, such that the proportion of each of the first 12 groups is 8%; and the proportion of the 13th group is 4%.

[0066] At this time, according to the normal distribution table, the capacity range of each group is shown in Table 1 and the continuation of Table 1.

[0067] Table 1

[0068]

[0069] Continuation of Table 1

[0070]

[0071] It can be known from this that after the above calculation of the designed cell capacity range based on the normal distribution rule, the designed cell capacity range is divided into 13 sub - ranges. For these 13 sub - ranges, the group 13 (83.9263 - 84.6000 Ah) with the largest capacity range can be regarded as the first sub - range, the group 12 (83.3350 - 83.9263 Ah) with the second - largest capacity range can be regarded as the second sub - range, and so on until the group 1 (79.1 - 80.0763 Ah) with the smallest cell capacity range is regarded as the thirteenth sub - range.

[0072] At this time, obtain the actual cell capacity of each cell, and based on the corresponding relationship between the actual cell capacity and the 13 sub - ranges, group each cell into the corresponding sub - range. For example, when the actual cell capacity of the current cell is obtained as 80.3 Ah, it can be known that this actual cell capacity falls into group 2, i.e., the twelfth sub - range, so the cell is grouped into the second sub - range. For example, when the actual cell capacity of the current cell is obtained as 82.8 Ah, it can be known that this actual cell capacity falls into group 10, i.e., the fourth sub - range, so the cell is grouped into the fourth sub - range. And so on, the 100 cells in this example are grouped.

[0073] Of course, considering that for some manufacturers with relatively weak production capacity, the distribution of cell capacities will be relatively wide. In this case, the designed cell capacity range can be divided into multiple grades, and the above calculations can be performed separately for the cell capacity ranges of each grade. For example, if the designed cell capacity range in the example is from 79.1 Ah to 90.1 Ah, this designed cell capacity range can be divided into two grades: the first grade: from 79.1 Ah to 84.6 Ah; the second grade: from 84.6 to 90.1 Ah.

[0074] In addition, considering that if some manufacturers have strong design capabilities and there will be no significant differences in the temperatures at different positions in the battery module, the designed cell capacity range can also be divided into grades for further subdivision, that is, divided into small range grades, and then the above calculations can be performed separately for the cell capacity ranges of each grade. For example, if the cell capacity range is from 79.1 Ah to 84.6 Ah, the cells can be divided into two grades: the first grade: from 79.1 Ah to 81.85 Ah; the second grade: from 81.85 Ah to 84.6 Ah.

[0075] Of course, regarding the number of grade divisions, the above two grades are just examples and are not restrictive. It can be divided into the required number of grades according to actual needs.

[0076] Using the above cell grouping method of the first embodiment, by obtaining the designed cell capacity range of the cells and dividing based on the normal distribution rule, it can ensure that the cell grouping process is more scientific and reasonable, making the number of cells in each sub-range relatively balanced and the capacity characteristics similar, thereby improving the accuracy of grouping. After cell grouping, the requirements of each module in the battery system can be more precisely matched. By combining cells with similar capacities together, the capacity differences within the battery system can be reduced, thereby enhancing the stability and consistency of the entire system, extending the battery service life, improving the safety and reliability of the battery system, enhancing the overall performance of the battery system, and enhancing the battery aging ability. In addition, this grouping method provides a clear basis for the screening and assembly of cells, making the production process more standardized and efficient. On the production line, workers can quickly allocate the cells to the corresponding sub-ranges according to the actual capacity of the cells, reducing the time and workload of screening and classification. At the same time, when assembling the battery module, since the cells have been grouped according to capacity, the assembly process is more convenient, improving the production efficiency.

[0077] <Second Embodiment>

[0078] Figure 3 It is a schematic block diagram of a cell arrangement method for a battery module according to the second embodiment of the present disclosure.

[0079] The second embodiment is the practical application of the cell grouping method of the first embodiment. After the cells are grouped based on the first embodiment, the cells are arranged in the battery module to assemble the battery module. That is, the second embodiment provides a method for arranging cells in a battery module.

[0080] As Figure 3 shown, the method for arranging cells in a battery module according to the second embodiment includes step S201 and step S202.

[0081] In step S201, based on the design information of the battery module, the first target arrangement position among the respective cell arrangement positions of the battery module is obtained, wherein, when the battery pack is operating, the cell arranged at the first target arrangement position has the highest cell temperature or the highest cell extrusion pressure.

[0082] Regarding the first target arrangement position, generally speaking, heat dissipation is more difficult and the temperature rise is higher at the middle position of the battery module; and there is structural adhesive on the side plate of the battery module to restrain the cells, which will cause uneven extrusion pressure on the cells at different positions in the battery module, and the extrusion pressure on the cells at the middle position is greater. Therefore, it is considered to regard the middle position of the battery module as the first target arrangement position.

[0083] More specifically, this step S201 can be further subdivided into: based on the design information, dividing the respective cell arrangement positions of the battery module so that it includes the first target arrangement position, the second target arrangement position, the third target arrangement position up to the Nth target arrangement position, wherein, when the battery pack is operating, the cell arranged at the second target arrangement position has the second highest cell temperature or the second highest cell extrusion pressure, the cell arranged at the third target arrangement position has the third highest cell temperature or the third highest cell extrusion pressure, and successively, the cell arranged at the Nth target arrangement position has the lowest cell temperature or the lowest cell extrusion pressure.

[0084] According to this step S201, different from the random arrangement in the traditional cell arrangement method, in this embodiment, the cell arrangement positions are pre-divided, so that the cell arrangement can be carried out in a planned and sequential manner. The cell arrangement positions of the battery module are carefully divided from high to low according to temperature and extrusion pressure, which can accurately grasp the thermal and mechanical characteristics of each position in the module, and provide guidance for the subsequent specific cell arrangement, that is, step S202.

[0085] In step S202, the cells within the first sub-range grouped into the N sub-ranges described in the first embodiment are used as the first cells, and the first cells are arranged at the first target arrangement position.

[0086] More specifically, step S202 can be further broken down into: arranging the battery cells within the first sub-range as the first battery cells at the first target arrangement position, arranging the battery cells within the second sub-range as the second battery cells at the second target arrangement position, and successively arranging the battery cells within the Nth sub-range as the Nth battery cells at the Nth target arrangement position.

[0087] Through step S202, the battery cells in the first sub-range with larger capacity and relatively better performance are arranged at the first target arrangement position where the working conditions are the most severe (such as the highest temperature or extrusion pressure). Because they themselves have stronger tolerance, they can age relatively slowly in such an environment. Similarly, the battery cells in other sub-ranges are correspondingly arranged at the corresponding working condition positions, making the aging rates of the battery cells in the entire battery module more balanced. This avoids the problem that the overall performance of the battery module prematurely deteriorates due to some battery cells aging rapidly under severe working conditions while other battery cells age slowly, thereby effectively improving the aging ability of the battery module. When the aging rates of the battery cells tend to be the same, the overall aging process of the battery module is delayed. For example, if a certain battery cell ages too fast, during the charge and discharge process of the battery module, this battery cell may first experience problems such as a significant decrease in capacity and an increase in internal resistance, thereby affecting the performance of the entire battery module. Through the reasonable arrangement of battery cells in step S202, the performances of the battery cells remain relatively synchronized throughout the entire service life cycle, extending the time during which the battery module can maintain good performance and improving its aging performance.

[0088] In addition, the battery cell arrangement method of the second embodiment, which includes step S201 and step S202, also provides a standardized operation process for the production of the battery module with clear battery cell arrangement rules. Production personnel can accurately place the battery cells in different sub-ranges at the corresponding target arrangement positions according to the corresponding relationship, improving production efficiency, reducing human errors in the production process, and facilitating large-scale production and quality control.

[0089] More specifically, in the battery cell arrangement method of the second embodiment, for the execution of step S202, it can be to select the first battery cells from the battery cells placed in the first battery cell placement part corresponding to the first sub-range and arrange the first battery cells at the first target arrangement position; select the second battery cells from the battery cells placed in the second battery cell placement part corresponding to the second sub-range and arrange the second battery cells at the second target arrangement position; and successively select the Nth battery cells from the battery cells placed in the Nth battery cell placement part corresponding to the Nth sub-range and arrange the Nth battery cells at the Nth target arrangement position. The battery cell placement part mentioned here is a part for placing, storing, or storing battery cells, such as a battery cell shelf or tray.

[0090] Using the cell arrangement method with the above configuration, the cells are placed in the corresponding cell placement parts according to sub-ranges, just like constructing an orderly warehousing system. During production, cells can be directly selected from specific placement parts and arranged at corresponding target positions, making the warehousing picking process clear and definite, improving the utilization rate of warehousing space and the efficiency of cell searching and extraction. For example, during large-scale production of battery modules, workers can quickly locate the required cells, reducing the time waste of searching for cells and enhancing the overall production rhythm. This corresponding relationship of the cell arrangement method with the above configuration ensures that different characteristic cells can be accurately obtained on the production line. Each cell placement part is specifically set for cells in a specific sub-range, supplying suitable cells for different target arrangement positions and ensuring the smoothness of the production process. For example, on an automated production line, the robotic arm can accurately grab cells from the corresponding placement part according to a preset program and place them at the designated position, reducing production stagnation caused by incorrect cell supply. Finally, selecting cells from a specific cell placement part and arranging them at the corresponding position helps to maintain the consistency of the quality of the battery module. The characteristics of the cells in each placement part are similar. Each time a cell is selected and arranged at the corresponding position, the performance of the cells at that position can be guaranteed to be relatively stable. For example, the cells at the first target arrangement position always use the cells from the first cell placement part, making the performance of the cells at this position fluctuate less during the entire production batch, thereby enhancing the quality stability of the entire battery module.

[0091] Here, still taking the example mentioned in the first embodiment as an illustration. After the cell grouping is completed, that is, divided into 13 sub-ranges, 100 cells can be allocated to different shelves corresponding to each sub-range according to their actual cell capacities. At this time, select 1 cell from, for example, shelf 1 corresponding to the largest range and arrange it at the middle position among the 25 cell arrangement positions that make up the battery module, that is, the 13th position; then, select 2 cells from, for example, shelf 2 corresponding to the second largest range and arrange them at the 12th positions on both sides of the middle 13th position, and so on, to complete the arrangement of 25 cells. The specific order is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1.

[0092] According to the cell arrangement method for the battery module as above, at this time, the cell capacity at the middle position of this battery module is the largest, which is 83.9263 - 84.6000 Ah.

[0093] When the battery of the randomly grouped module ages to 80%, the battery capacity is 79.1 Ah x 80% = 63.28 Ah. For the module assembled in the current permutation and combination method, the corresponding aging state of the battery is 63.28 / 84.6 x 100% = 74.7%. It can be seen from this that the battery can continue to age to 74.7% before reaching the same effect as the original aging to 80%. See Figure 5, by extending the original 35°C trend line, it can be seen that when the battery ages to 74.7%, it will experience approximately 4200 cycles. Based on this, the improvement in the battery's aging performance can be roughly calculated as (4200 - 3000) / 3000 x 100% = 40%. Considering that the temperature difference between the middle and the edge of the module will not always be 10°C, this ratio will be lower than 40%. Assuming that the temperature difference between the middle and the edge of the battery module is 10 degrees Celsius for 25% of the time, the aging performance of the battery will be improved by 40% x 25% = 10%.

[0094] In the above example, the first target placement position takes the middle position as an example. However, considering the actual situation, due to the design of the cooling circuit, the highest cell position may not necessarily be at the center position. For example, the inlet of the cooling water pipe is close to one section of the module, while the outlet is close to another section. Therefore, in this case, the first target placement position is the placement position closest to the outlet of the cooling water pipe. The coolant temperature at the outlet of the cooling water pipe is relatively high, and the cooling capacity is relatively weak. Placing the cells in the first sub-range at the position closest to the outlet of the cooling water pipe, since these cells have a large capacity and good performance, they have relatively strong tolerance to temperature and can still maintain a good working state under relatively poor cooling conditions, thereby making more reasonable use of the cooling resources and improving the overall efficiency of the cooling system. Moreover, in the battery module, the position close to the outlet of the cooling water pipe may be a key area for temperature control. If the cells at this position have poor performance, they are easily affected by high temperature and may malfunction, thereby affecting the performance of the entire battery module. Placing the cells in the first sub-range here can utilize their good performance to resist the possible high-temperature risk, play a role in protecting the cells at the key position, and enhance the reliability of the battery module. From the inlet to the outlet of the cooling water pipe, the coolant temperature gradually increases, and the temperature of the battery module will also show a certain gradient distribution. Placing the cells in the first sub-range near the outlet can optimize the temperature distribution of the entire battery module according to the relationship between the cell performance and the temperature gradient, make the temperature difference between the cells more reasonable, reduce the problem of uneven battery performance caused by excessive temperature difference, and improve the overall performance and lifespan of the battery module.

[0095] <Third Embodiment>

[0096] The third embodiment of the present disclosure provides a cell placement system, including N cell placement parts, the N cell placement parts corresponding one-to-one to the N sub-ranges described in the first embodiment, and an automatic transportation part that automatically transports the cells into the corresponding cell placement parts based on the actual cell capacity of the produced cells.

[0097] Using the battery cell layout system with the above configuration, the automatic transportation unit (such as a robotic arm, conveyor mechanism, robot, etc.) automatically transports the battery cells to the corresponding battery cell placement unit according to the actual battery cell capacity, realizing the automated process of battery cells from production offline to storage. This greatly reduces the workload of manual sorting and handling, improves the efficiency of battery cell storage, reduces the errors that may be caused by manual operations, and makes the entire battery cell storage link smoother and more efficient. During large-scale battery cell production, it can quickly respond to the production rhythm and timely classify and store the produced battery cells. For example, on a high-speed production line, the automatic transportation unit can process the produced battery cells in real time to ensure that the production progress is not affected by delays in the storage link, improving the operating efficiency of the entire production system. Automatically classifying the battery cells into the corresponding placement units according to the capacity range helps to ensure the capacity consistency of the battery cells in each placement unit. This is crucial for the selection of battery cells during subsequent battery module production, can reduce the problem of unstable battery module performance caused by individual differences in battery cells, and improves the overall quality of the battery module. The automated transportation and accurate placement correspondence effectively avoid the mixing phenomenon of battery cells with different capacity ranges. As mentioned in the background art, the mixing of battery cells may lead to a serious decline in the performance of the battery module. The third-party system reduces this risk from the source through strict classified storage, ensuring the aging ability of the battery cells and subsequent battery products. Finally, when producing battery modules, the battery cells with the required capacity range can be directly obtained from the corresponding battery cell placement unit, realizing the efficient docking of the warehousing and production links. This orderly storage method makes it more convenient to retrieve battery cells on the production line, reduces the production waiting time, improves the production efficiency, and is also conducive to the formulation and implementation of production plans.

[0098] <Other embodiments>

[0099] The present disclosure also provides a battery pack, wherein the battery cells in the battery module of the battery pack are arranged according to the battery cell layout method described in the second embodiment. The present disclosure also provides a vehicle including the battery pack.

[0100] Since both the battery pack and the vehicle adopt the battery cell grouping method of the first embodiment and the battery cell layout method of the second embodiment, and the layout can be performed by the battery cell layout system of the third embodiment, various technical effects similar to those above can be achieved.

[0101] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions may occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for grouping a predetermined number of battery cells, characterized in that: The cell grouping method comprises: Obtaining a designed battery cell capacity range of the plurality of battery cells; Calculating the designed cell capacity range based on a normal distribution rule, dividing the designed cell capacity range into N consecutive sub-ranges, i.e., a first sub-range with the largest cell capacity range, a second sub-range with the second largest cell capacity range, and an Nth sub-range with the smallest cell capacity range, wherein N is an integer greater than 1; and The actual cell capacity of each of the cell is obtained, and based on the correspondence between the actual cell capacity and the N sub-ranges, each of the cell is grouped into a corresponding sub-range.

2. The method for grouping cells according to claim 1, characterized in that: include: Arrange N battery cell placement portions so that the N battery cell placement portions are arranged in a one-to-one correspondence with the N sub-ranges, and The battery cells grouped into each of the sub-ranges are placed in the corresponding battery cell placement portion.

3. The method for grouping cells according to claim 1 or 2, characterized in that: include: Divide the designed battery cell capacity range into multiple gears, and The calculation is performed for the battery cell capacity range of each gear.

4. A method for arranging cells for a battery module, characterized in that: include: Based on the design information of the battery module, a first target arrangement position among the battery cell arrangement positions of the battery module is obtained, wherein when the battery module is working, the battery cell arranged at the first target arrangement position has the highest battery cell temperature or the highest battery cell squeezing force; as well as The battery cells grouped into the first sub-range among the N sub-ranges according to any one of claims 1 to 3 are used as first battery cells, and the first battery cells are arranged at the first target arrangement positions.

5. The battery cell arrangement method according to claim 4, characterized in that: include: Based on the design information, the battery cell layout positions of the battery module are divided to include the first target layout position, the second target layout position, the third target layout position and up to the Nth target layout position, wherein, when the battery module is working, the battery cell arranged at the second target layout position has a second highest battery cell temperature or a second highest battery cell squeezing pressure, the battery cell arranged at the third target layout position has a third highest battery cell temperature or a third highest battery cell squeezing pressure, and sequentially, the battery cell arranged at the Nth target layout position has a lowest battery cell temperature or a lowest battery cell squeezing pressure, and The battery cells within the first sub-range are arranged as first battery cells at the first target arrangement position, and the battery cells within the second sub-range are arranged as second battery cells at the second target arrangement position. Sequentially, the battery cells within the Nth sub-range are arranged as Nth battery cells at the Nth target arrangement position.

6. The battery cell arrangement method according to claim 5, characterized in that: include, Selecting the first battery cell from the battery cells placed in the first battery cell placement portion corresponding to the first sub-range, and placing the first battery cell at the first target placement position; Selecting the second battery cell from the battery cells placed in the second battery cell placement portion corresponding to the second sub-range, and placing the second battery cell at the second target placement position; as well as In turn, The Nth battery cell is selected from the battery cells placed in the Nth battery cell placement portion corresponding to the Nth sub-range, and the Nth battery cell is arranged at the Nth target arrangement position.

7. The battery cell arrangement method according to any one of claims 4 to 6, characterized in that: The first target placement position is a central position among the placement positions of the battery cells, or The first target arrangement position is the arrangement position closest to the cooling water pipe outlet among the battery cell arrangement positions.

8. A battery cell arrangement system, characterized in that: include: N battery cell placement portions, the N battery cell placement portions corresponding one to one with the N sub-ranges described in claim 1, and The automatic transporting unit automatically transports the produced battery cells to corresponding battery cell placement units based on actual battery cell capacities.

9. A battery pack, characterized in that: Comprising more than one battery module, Wherein, the battery cells in the battery module are arranged according to the battery cell arrangement method according to any one of claims 4-7.

10. A vehicle, characterized in that: The vehicle includes the battery pack according to claim 9.

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