Battery cell matching system for improving cycle life

Abstract

The application relates to the technical field of automobile batteries, in particular to an electric core matching system for improving cycle life, which comprises an electric core parameter acquisition module, which obtains the initial capacity, internal resistance value and voltage curve of the electric core to be matched for a new energy automobile; a dynamic attenuation modeling module, which establishes a dynamic attenuation model according to the capacity attenuation and internal resistance growth data in the cycle use process of the electric core; a matching optimization module, which combines the dynamic attenuation model output and the current matching strategy to adjust the electric core group in the matching scheme to obtain a battery group; a high-temperature correction module, which dynamically adjusts the matching correction value of the high-temperature cycle attenuation coefficient according to the attenuation performance of the electric core in the battery group under high-temperature cycle; and a control module, which is used to determine the screening threshold of the static parameters of the electric core according to the maximum difference of the initial capacities of the electric cores in the same battery group, or to determine the dynamic characteristic weight coefficient according to the internal resistance difference of the electric cores in the battery group. The application improves the stability of the electric core matching.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile battery, and particularly relates to a battery cell grouping system for improving cycle life. BACKGROUND

[0002] With the rapid development of the new energy automobile industry, the cycle life of the power battery as a core component directly affects the endurance, use cost and safety of the vehicle. At present, the power battery is mostly used in the form of multiple battery cells in series or parallel to constitute a battery pack, and the consistency of the battery cells is a key factor determining the cycle life of the battery pack.

[0003] Chinese Patent Publication No. CN109244524A discloses a battery cell grouping system, which comprises a grouping circulation area, a grouping mechanism, a battery cell feeding mechanism and a conveying device. One side of the grouping circulation area is provided with a grouping feeding position, and the other side of the grouping circulation area is provided with a grouping discharging position. The one side of the grouping circulation area is opposite to the other side. At least one first carrier is arranged in the grouping circulation area, and the first carrier moves circularly between the grouping feeding position and the grouping discharging position. The first carrier is used for placing battery cells. The grouping mechanism is arranged at one side of the grouping feeding position and is used for grouping the battery cells in the first carrier. The battery cell feeding mechanism is arranged between the grouping discharging position and the conveying device and is used for feeding the grouped battery cells in the first carrier to the conveying device. The conveying device is used for conveying the grouped battery cells. It can be seen that the battery cell grouping system only realizes the combination through physical feeding and mechanical grouping, which may cause the initial performance difference of the battery cells in the same battery pack to be too large, and the charging and discharging is not balanced in the early stage of the cycle, thereby causing the decrease of the grouping stability. SUMMARY

[0004] Therefore, the present application provides a battery cell grouping system for improving cycle life to overcome the problem that the initial performance difference of the battery cells in the same battery pack is too large due to only realizing the combination through physical feeding and mechanical grouping in the prior art, the charging and discharging is not balanced in the early stage of the cycle, thereby causing the decrease of the grouping stability.

[0005] To achieve the above-mentioned purpose, the present application provides a battery cell grouping system for improving cycle life, which comprises:

[0006] A battery cell parameter acquisition module is used to acquire the initial capacity, internal resistance value and voltage curve of the battery cells to be grouped for a new energy automobile.

[0007] A dynamic attenuation modeling module is connected with the battery cell parameter acquisition module and is used to establish a dynamic attenuation model according to the capacity attenuation and internal resistance growth data in the cycle use process of the battery cells.

[0008] a group optimization module connected with the dynamic attenuation modeling module, configured to combine the dynamic attenuation model output and the current group strategy to adjust the cell groups in the group scheme to obtain the battery pack;

[0009] a high-temperature correction module connected with the group optimization module, configured to dynamically adjust the group correction value of the high-temperature cycle attenuation coefficient according to the attenuation performance of the cells in the battery pack under high-temperature cycles;

[0010] a control module connected with the cell parameter acquisition module, the dynamic attenuation modeling module, the group optimization module and the high-temperature correction module, respectively, configured to determine the screening threshold of the cell static parameters according to the maximum difference of the initial capacities of the cells in the same battery pack, or to determine the dynamic characteristic weight coefficient according to the internal resistance difference of the cells in the battery pack, and to determine the group correction value of the high-temperature cycle attenuation coefficient according to the attenuation rate of the available capacity of the battery pack.

[0011] Further, the control module determines that the stability of the cell group meets the requirements in response to the maximum difference of the initial capacities of the cells being less than or equal to a preset first difference.

[0012] The control module determines that the stability of the cell group does not meet the requirements in response to the maximum difference of the initial capacities of the cells being greater than the preset first difference.

[0013] Further, the control module preliminarily determines that the dynamic consistency of the battery pack does not meet the requirements in response to the maximum difference of the initial capacities of the cells being greater than the preset first difference and less than or equal to a preset second difference.

[0014] Further, the control module decreases the screening threshold of the cell static parameters in response to the maximum difference of the initial capacities of the cells being greater than the preset second difference.

[0015] The decrease range of the screening threshold of the cell static parameters is determined by the difference between the maximum difference of the initial capacities of the cells and the preset second difference.

[0016] Further, the control module determines that the dynamic consistency of the battery pack meets the requirements in response to the internal resistance difference of the cells in the battery pack being less than or equal to a preset first internal resistance difference.

[0017] The control module determines that the dynamic consistency of the battery pack does not meet the requirements in response to the internal resistance difference of the cells in the battery pack being greater than the preset first internal resistance difference.

[0018] Further, the control module increases the dynamic characteristic weight coefficient in response to the internal resistance difference of the cells in the battery pack being greater than the preset first internal resistance difference and less than or equal to a preset second internal resistance difference.

[0019] Further, the control module preliminarily determines that the charge-discharge equalization of the battery pack does not meet the requirement in response to the internal resistance difference of the plurality of battery cells in the battery pack being greater than the preset second internal resistance difference.

[0020] Further, the increase range of the dynamic characteristic weight coefficient is determined by the difference between the internal resistance difference of the plurality of battery cells in the battery pack and the preset first internal resistance difference.

[0021] Further, the control module determines that the charge-discharge equalization of the battery pack meets the requirement in response to the attenuation rate of the available capacity of the battery pack being less than or equal to the preset attenuation rate.

[0022] The control module determines that the charge-discharge equalization of the battery pack does not meet the requirement and increases the group matching correction value of the high-temperature cycle attenuation coefficient in response to the attenuation rate of the available capacity of the battery pack being greater than the preset attenuation rate.

[0023] Further, the increase range of the group matching correction value of the high-temperature cycle attenuation coefficient is determined by the difference between the attenuation rate of the available capacity of the battery pack and the preset attenuation rate.

[0024] Compared with the prior art, the system has the beneficial effects that the system adjusts the screening threshold of the static parameters of the battery cells according to the maximum difference of the initial capacities of the plurality of battery cells in the same battery pack, reduces the screening threshold of the static parameters of the battery cells, improves the initial group consistency, lays a foundation for prolonging the cycle life, adjusts the dynamic characteristic weight coefficient according to the internal resistance difference of the plurality of battery cells in the battery pack, increases the dynamic characteristic weight coefficient, adapts the group matching scheme to the dynamic attenuation law in the whole life cycle of the automobile, delays the performance differentiation in the cycle, adjusts the group matching correction of the high-temperature cycle attenuation coefficient according to the attenuation rate of the available capacity of the battery pack, increases the group matching correction value of the high-temperature cycle attenuation coefficient, makes the thermal response characteristics of the battery cells in the same group consistent, cooperates with the dynamic equalization strategy of the BMS, and finally realizes the cycle life improvement of the battery pack, and improves the stability of the battery cell group matching.

[0025] Further, the system of the present application adjusts the screening threshold of the static parameters of the battery cell by setting the preset first difference and the preset second difference, due to the difference in material uniformity in the production process of the battery cell, the initial capacity of the same batch of battery cells has discreteness, and the performance differentiation in the cycle is accelerated after direct matching, by reducing the screening threshold of the static parameters of the battery cell, the initial matching consistency can be improved, which lays a foundation for prolonging the cycle life, and further improves the stability of the battery cell matching.

[0026] Further, the system of the present application adjusts the screening threshold of the static parameters of the battery cell by setting the preset first difference and the preset second difference, due to the difference in material uniformity in the production process of the battery cell, the initial capacity of the same batch of battery cells has discreteness, and the performance differentiation in the cycle is accelerated after direct matching, by reducing the screening threshold of the static parameters of the battery cell, the initial matching consistency can be improved, which lays a foundation for prolonging the cycle life, and further improves the stability of the battery cell matching.

[0027] Further, the system of the present application adjusts the screening threshold of the static parameters of the battery cell by setting the preset first difference and the preset second difference, due to the difference in material uniformity in the production process of the battery cell, the initial capacity of the same batch of battery cells has discreteness, and the performance differentiation in the cycle is accelerated after direct matching, by reducing the screening threshold of the static parameters of the battery cell, the initial matching consistency can be improved, which lays a foundation for prolonging the cycle life, and further improves the stability of the battery cell matching. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The overall structure block diagram of the battery cell matching system for improving the cycle life of the embodiment of the present application;

[0029] Figure 2 The logic flow chart of the process of determining the screening threshold of the static parameters of the battery cell matching system for improving the cycle life of the embodiment of the present application;

[0030] Figure 3 The logic flow chart of the process of determining the dynamic characteristic weight coefficient of the battery cell matching system for improving the cycle life of the embodiment of the present application;

[0031] Figure 4 The logic flow chart of the process of determining the matching correction value of the high-temperature cycle attenuation coefficient of the battery cell matching system for improving the cycle life of the embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the objects, technical schemes, and advantages of the application clearer, the following further describes the application with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the application and not to limit the application.

[0033] The preferred embodiments of the application are described below with reference to the drawings. Those skilled in the art should understand that the embodiments are only used to explain the technical principles of the application and not to limit the protection scope of the application.

[0034] It should be noted that, in the description of the application, the terms "upper", "lower", "left", "right", "inner", "outer", and the like indicating the direction or positional relationship are based on the direction or positional relationship shown in the drawings, which is only for the convenience of description and does not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0035] In addition, it should also be noted that, in the description of the application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", and "connection" should be understood broadly, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or can be connected inside two elements. Those skilled in the art can understand the specific meaning of the above terms in the application according to the specific circumstances.

[0036] Please refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 , which are respectively the overall structure block diagram of the battery cell grouping system for improving cycle life, the logic flowchart of the screening threshold value process for determining the static parameters of the battery cell, the logic flowchart of the process for determining the dynamic characteristic weight coefficient, and the logic flowchart of the process for determining the grouping correction value of the high-temperature cycle attenuation coefficient. The battery cell grouping system for improving cycle life comprises:

[0037] A battery cell parameter acquisition module is configured to obtain the initial capacity, internal resistance value, and voltage curve of the battery cell to be grouped for a new energy vehicle;

[0038] A dynamic attenuation modeling module is connected to the battery cell parameter acquisition module and is configured to establish a dynamic attenuation model according to the capacity attenuation and internal resistance growth data in the cycle use process of the battery cell;

[0039] A grouping optimization module is connected to the dynamic attenuation modeling module and is configured to combine the dynamic attenuation model output and the current grouping strategy to adjust the battery cell group in the grouping scheme to obtain a battery pack;

[0040] a high-temperature correction module connected with the group optimization module, configured to dynamically adjust the group correction value of the high-temperature cycle attenuation coefficient according to the attenuation performance of the cells in the battery pack under high-temperature cycles;

[0041] a control module connected with the cell parameter acquisition module, the dynamic attenuation modeling module, the group optimization module and the high-temperature correction module, respectively, configured to determine the screening threshold of the cell static parameters according to the maximum difference of the initial capacities of the cells in the same battery pack, or determine the dynamic characteristic weight coefficient according to the resistance difference of the cells in the battery pack, and determine the group correction value of the high-temperature cycle attenuation coefficient according to the attenuation rate of the available capacity of the battery pack.

[0042] Specifically, the dynamic attenuation model can be a double exponential decay model, an equivalent circuit decay model or a gradient boosting tree model.

[0043] Specifically, the screening threshold of the cell static parameters is the allowed difference range or critical value set for the static performance parameters (such as initial capacity, initial resistance, voltage, etc.) of the cells when they are shipped or before grouping.

[0044] Specifically, the dynamic characteristic weight coefficient is a quantitative influence factor given to the dynamic performance parameters (such as the change rate of the resistance with cycles, the voltage response characteristics during charging and discharging, etc.) of the cells in the group optimization process.

[0045] Specifically, the group correction value of the high-temperature cycle attenuation coefficient is an adjustment parameter for correcting the grouping strategy, which is obtained by quantitative calculation for the attenuation characteristics (such as the capacity attenuation rate, the resistance growth rate) of the cells under high-temperature cycles.

[0046] In the implementation, the system described in the application sets the cell parameter acquisition module, the dynamic attenuation modeling module, the group optimization module, the high-temperature correction module, and the control module, adjusts the screening threshold of the static parameters of the cells according to the maximum difference of the initial capacities of the cells in the same battery group, reduces the screening threshold of the static parameters of the cells, improves the initial consistency of the group, lays the foundation for prolonging the cycle life, adjusts the dynamic characteristic weight coefficient according to the internal resistance difference of the cells in the battery group, increases the dynamic characteristic weight coefficient, adapts the group scheme to the dynamic attenuation law of the whole life cycle of the automobile, delays the performance differentiation in the cycle, adjusts the group correction of the high-temperature cycle attenuation coefficient according to the attenuation rate of the available capacity of the battery group, increases the group correction value of the high-temperature cycle attenuation coefficient, makes the thermal response characteristics of the cells in the same group consistent, cooperates with the dynamic balancing strategy of the BMS, and finally realizes the cycle life improvement of the battery group, and improves the stability of the cell group.

[0047] Specifically, the control module determines that the stability of the cell group meets the requirements in response to the maximum difference of the initial capacities of the cells being less than or equal to a preset first difference;

[0048] The control module determines that the stability of the cell group does not meet the requirements in response to the maximum difference of the initial capacities of the cells being greater than the preset first difference.

[0049] Specifically, the control module preliminarily determines that the dynamic consistency of the battery group does not meet the requirements in response to the maximum difference of the initial capacities of the cells being greater than the preset first difference and less than or equal to a preset second difference, and determines whether the dynamic consistency of the battery group meets the requirements according to the internal resistance difference of the cells in the battery group.

[0050] It can be understood that the preset first difference is less than the preset second difference, and the three intervals divided by the preset first difference and the preset second difference correspond to three situations respectively.

[0051] The first interval is that the maximum difference of the initial capacities of the cells is less than or equal to the preset first difference, and the corresponding situation is that the stability of the cell group meets the requirements;

[0052] The second interval is that the maximum difference of the initial capacities of the plurality of battery cells is greater than the preset first difference and less than or equal to a preset second difference, and the corresponding case is that, due to complex automobile working conditions (such as low temperature-10 DEG C to high temperature 40 DEG C, and frequent switching of charge and discharge rates), the dynamic characteristics (capacity attenuation rate and internal resistance growth trend) of the battery cells with consistent static parameters are highlighted in the cycle, which may lead to collapse of consistency in the later stage;

[0053] The third interval is that the maximum difference of the initial capacities of the plurality of battery cells is greater than the preset second difference, and the corresponding case is that, due to differences in material uniformity in the production process of the battery cells, the initial capacities of the battery cells in the same batch exist discreteness, and the performance differentiation is accelerated in the cycle after direct grouping.

[0054] It can be understood that the preset first difference is generally selected in the range of [8 Ah, 12 Ah], and the preset second difference is generally selected in the range of [13 Ah, 17 Ah].

[0055] Preferably, the preferred embodiment of the preset first difference is 10 Ah, and the preferred embodiment of the preset second difference is 15 Ah.

[0056] Specifically, Ah is the unit of the maximum difference of the initial capacities of the plurality of battery cells, and means ampere-hour.

[0057] Specifically, the maximum difference of the initial capacities of the plurality of battery cells is the difference between the maximum initial capacity and the minimum initial capacity of the battery cells in the same battery pack.

[0058] In the implementation, the system determines the stability of the battery cell grouping by setting the preset first difference and the preset second difference, reduces the influence of the decrease in the accuracy of the battery cell grouping due to inaccurate determination of the stability of the battery cell grouping, and further improves the stability of the battery cell grouping.

[0059] Specifically, the control module reduces the screening threshold of the static parameters of the battery cells in response to the maximum difference of the initial capacities of the plurality of battery cells being greater than the preset second difference.

[0060] The reduction range of the screening threshold of the static parameters of the battery cells is determined by the difference between the maximum difference of the initial capacities of the plurality of battery cells and the preset second difference.

[0061] Specifically, if the difference between the maximum difference of the initial capacities of the plurality of battery cells and the preset second difference is within 5 Ah, the screening threshold of the static parameter of the battery cell is reduced to 0.9 times of the original value; when the difference between the maximum difference of the initial capacities of the plurality of battery cells and the preset second difference exceeds 5 Ah, the screening threshold of the static parameter of the battery cell is reduced to 0.9 times of the original value, and for every 2 Ah exceeding, the screening threshold of the static parameter of the battery cell is reduced by 0.5 Ah. For example, if the difference between the maximum difference of the initial capacities of the plurality of battery cells and the preset second difference is 9 Ah, and the screening threshold of the static parameter of the battery cell is 5 Ah, the screening threshold of the static parameter of the battery cell after reduction is 5*0.9-0.5*2=3.5 Ah.

[0062] In implementation, the system of the present application adjusts the screening threshold of the static parameter of the battery cell by setting the preset first difference and the preset second difference. Since the uniformity of the materials in the production process of the battery cell is different, the initial capacities of the battery cells in the same batch are discrete, the performance differentiation in the cycle is accelerated after direct grouping, and the initial grouping consistency can be improved by reducing the screening threshold of the static parameter of the battery cell, which lays a foundation for prolonging the cycle life and further improves the stability of the battery cell grouping.

[0063] Specifically, the control module determines that the dynamic consistency of the battery pack meets the requirements in response to the internal resistance difference of the plurality of battery cells in the battery pack being less than or equal to a preset first internal resistance difference.

[0064] The control module determines that the dynamic consistency of the battery pack does not meet the requirements in response to the internal resistance difference of the plurality of battery cells in the battery pack being greater than the preset first internal resistance difference.

[0065] Specifically, the control module increases the dynamic characteristic weight coefficient in response to the internal resistance difference of the plurality of battery cells in the battery pack being greater than the preset first internal resistance difference and less than or equal to a preset second internal resistance difference.

[0066] Specifically, the control module preliminarily determines that the charge-discharge balance of the battery pack does not meet the requirements in response to the internal resistance difference of the plurality of battery cells in the battery pack being greater than the preset second internal resistance difference, and determines whether the charge-discharge balance of the battery pack meets the requirements according to the attenuation rate of the available capacity of the battery pack.

[0067] It can be understood that the preset first internal resistance difference is less than the preset second internal resistance difference, and the three intervals divided by the preset first internal resistance difference and the preset second internal resistance difference correspond to three situations respectively.

[0068] The first interval is that the internal resistance difference of the plurality of battery cells in the battery pack is less than or equal to the preset first internal resistance difference, and the corresponding situation is that the dynamic consistency of the battery pack meets the requirements.

[0069] The second interval is that the internal resistance difference of the plurality of battery cells in the battery pack is greater than the preset first internal resistance difference and less than or equal to the preset second internal resistance difference, and the corresponding situation is that, due to complex automobile working conditions (such as low temperature-10 DEG C to high temperature 40 DEG C, and frequent switching of charge-discharge rate), the dynamic characteristics (capacity attenuation rate and internal resistance growth trend) of the battery cells with consistent static parameters are highlighted in the cycle, which may cause the consistency to collapse in the later period.

[0070] The third interval is that the internal resistance difference of the plurality of battery cells in the battery pack is greater than the preset second internal resistance difference, and the corresponding situation is that, due to insufficient charge-discharge balancing of the battery pack, the local battery cells are prematurely aged, and the overall cycle life is lowered.

[0071] It can be understood that the preset first internal resistance difference is generally selected in the range of [5mΩ, 7mΩ], and the preset second internal resistance difference is generally selected in the range of [8mΩ, 10mΩ].

[0072] Preferably, the preferred embodiment of the preset first internal resistance difference is 6mΩ, and the preferred embodiment of the preset second internal resistance difference is 9mΩ.

[0073] Specifically, the internal resistance difference of the plurality of battery cells in the battery pack is the difference between the maximum battery cell internal resistance and the minimum battery cell internal resistance in the same battery pack.

[0074] In the implementation, the system determines the dynamic consistency of the battery pack by setting the preset first internal resistance difference and the preset second internal resistance difference, reduces the influence of the decrease in the stability of the battery cell grouping due to the inaccurate determination of the dynamic consistency of the battery pack, and further improves the stability of the battery cell grouping.

[0075] Specifically, the increase range of the dynamic characteristic weight coefficient is determined by the difference between the internal resistance difference of the plurality of battery cells in the battery pack and the preset first internal resistance difference.

[0076] Specifically, when the difference between the internal resistance difference of the plurality of battery cells in the battery pack and the preset first internal resistance difference is within 3mΩ, the dynamic characteristic weight coefficient is increased to 1.1 times of the original value; when the difference between the internal resistance difference of the plurality of battery cells in the battery pack and the preset first internal resistance difference exceeds 3mΩ, the dynamic characteristic weight coefficient is increased by 0.05 for each 1mΩ on the basis of being increased to 1.1 times of the original value, for example, the difference between the internal resistance difference of the plurality of battery cells in the battery pack and the preset first internal resistance difference is 5mΩ, the current dynamic characteristic weight coefficient is 0.5, and the increased dynamic characteristic weight coefficient is 0.5*1.1+0.05*2=0.65.

[0077] In the implementation, the system adjusts the dynamic characteristic weight coefficient by setting a preset first internal resistance difference and a preset second internal resistance difference. Due to the complex working conditions of the automobile (such as low temperature-10℃ to high temperature 40℃ and frequent switching of the charge-discharge rate), the dynamic characteristics (capacity attenuation rate and internal resistance growth trend) of the battery cells with consistent static parameters differ significantly in the cycle, which may cause the consistency to collapse in the later stage. By increasing the dynamic characteristic weight coefficient, the matching scheme can adapt to the dynamic attenuation law of the whole life cycle of the automobile, delay the performance differentiation in the cycle, and further improve the stability of the battery cell matching.

[0078] Specifically, the control module determines that the charge-discharge balance of the battery pack meets the requirements in response to the attenuation rate of the available capacity of the battery pack being less than or equal to a preset attenuation rate.

[0079] The control module determines that the charge-discharge balance of the battery pack does not meet the requirements and increases the matching correction value of the high-temperature cycle attenuation coefficient in response to the attenuation rate of the available capacity of the battery pack being greater than the preset attenuation rate.

[0080] It can be understood that the two intervals divided by the preset attenuation rate correspond to two situations respectively.

[0081] The first interval is that the attenuation rate of the available capacity of the battery pack is less than or equal to the preset attenuation rate, and the corresponding situation is that the charge-discharge balance of the battery pack meets the requirements.

[0082] The second interval is that the attenuation rate of the available capacity of the battery pack is greater than the preset attenuation rate, and the corresponding situation is that the local battery cells are prematurely aged due to the insufficient charge-discharge balance of the battery pack, thereby reducing the overall cycle life.

[0083] It can be understood that the preset attenuation rate is generally selected in the range of [0.04% / cycle, 0.06% / cycle].

[0084] Preferably, the preferred embodiment of the preset attenuation rate is 0.05% / cycle.

[0085] Specifically, the attenuation rate of the available capacity of the battery pack is the decrease amplitude of the available capacity in the first 1000 charge-discharge cycles.

[0086] In the implementation, the system determines the charge-discharge balance of the battery pack by setting the preset attenuation rate, reduces the influence of the decrease in the stability of the battery cell matching due to the inaccurate determination of the charge-discharge balance of the battery pack, and further improves the stability of the battery cell matching.

[0087] Specifically, the increase range of the matching correction value of the high-temperature cycle attenuation coefficient is determined by the difference between the attenuation rate of the available capacity of the battery pack and the preset attenuation rate.

[0088] Specifically, when the difference between the attenuation rate of the available capacity of the battery pack and the preset attenuation rate is within 0.03% / cycle, the matching correction value of the high-temperature cycle attenuation coefficient is increased to 1.2 times of the original value; when the difference between the attenuation rate of the available capacity of the battery pack and the preset attenuation rate exceeds 0.03% / cycle, on the basis of being increased to 1.2 times of the original value, the matching correction value of the high-temperature cycle attenuation coefficient is increased by 0.05 for each 0.01% / cycle, for example, when the difference between the attenuation rate of the available capacity of the battery pack and the preset attenuation rate is 0.05% / cycle, and the matching correction value of the current high-temperature cycle attenuation coefficient is 0.8, the matching correction value of the high-temperature cycle attenuation coefficient after being increased is 0.8*1.2+0.05*2=1.06.

[0089] In implementation, the system described in the application adjusts the matching correction of the high-temperature cycle attenuation coefficient by setting the preset attenuation rate. Due to the imbalance of the charging and discharging of the battery pack, the local battery cells are prematurely aged, which reduces the overall cycle life. By increasing the matching correction value of the high-temperature cycle attenuation coefficient, the thermal response characteristics of the battery cells in the same group can be made consistent, and the BMS dynamic balancing strategy is used to ultimately improve the cycle life of the battery pack and further improve the stability of the battery cell matching.

[0090] So far, the technical solutions of the application have been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the application, and the technical solutions after the changes or replacements will fall within the protection scope of the application.

Claims

1. A cell matching system for improving cycle life, characterized by, The application relates to a battery pack parameter acquisition and optimization system for new energy vehicles. The system comprises an electric core parameter acquisition module, a dynamic attenuation modeling module, a pack optimization module, a high-temperature correction module and a control module. The electric core parameter acquisition module is used to acquire the initial capacity, internal resistance value and voltage curve of an electric core to be matched in a new energy vehicle. The dynamic attenuation modeling module is connected with the electric core parameter acquisition module and is used to establish a dynamic attenuation model according to the capacity attenuation and internal resistance growth data in the electric core cycle process. The pack optimization module is connected with the dynamic attenuation modeling module and is used to combine the dynamic attenuation model output and the current matching strategy to adjust the electric core group in the matching scheme to obtain a battery pack. The high-temperature correction module is connected with the pack optimization module and is used to dynamically adjust the matching correction value of the high-temperature cycle attenuation coefficient according to the attenuation performance of the electric cores in the battery pack under high-temperature cycle.

2. The improved cycle life cell pairing system of claim 1, wherein, The control module is connected with the electric core parameter acquisition module, the dynamic attenuation modeling module, the pack optimization module and the high-temperature correction module respectively. The control module determines the screening threshold of the electric core static parameter according to the maximum difference of the initial capacities of the electric cores in the same battery pack, or determines the dynamic characteristic weight coefficient according to the internal resistance difference of the electric cores in the battery pack, and determines the matching correction value of the high-temperature cycle attenuation coefficient according to the attenuation rate of the available capacity of the battery pack.

3. The system for pairing cells for improved cycle life of claim 2, wherein, The control module determines that the stability of the electric core matching meets the requirements when the maximum difference of the initial capacities of the electric cores is less than or equal to a preset first difference.

4. The system for pairing cells for improved cycle life of claim 3, wherein, The control module determines that the stability of the electric core matching does not meet the requirements when the maximum difference of the initial capacities of the electric cores is greater than the preset first difference. The control module preliminarily determines that the dynamic consistency of the battery pack does not meet the requirements when the maximum difference of the initial capacities of the electric cores is greater than the preset first difference and less than or equal to a preset second difference.

5. The system for pairing cells for improved cycle life of claim 3, wherein, The control module reduces the screening threshold of the electric core static parameter when the maximum difference of the initial capacities of the electric cores is greater than the preset second difference. The reduction range of the screening threshold of the electric core static parameter is determined by the difference between the maximum difference of the initial capacities of the electric cores and the preset second difference.

6. The system for pairing cells for improved cycle life of claim 5, wherein, The control module determines that the dynamic consistency of the battery pack meets the requirements when the internal resistance difference of the electric cores in the battery pack is less than or equal to a preset first internal resistance difference.

7. The system for pairing cells for improved cycle life of claim 6, wherein, The control module determines that the dynamic consistency of the battery pack does not meet the requirements when the internal resistance difference of the electric cores in the battery pack is greater than the preset first internal resistance difference.

8. The system for pairing cells for improved cycle life of claim 7, wherein, The control module increases the dynamic characteristic weight coefficient when the internal resistance difference of the electric cores in the battery pack is greater than the preset first internal resistance difference and less than or equal to a preset second internal resistance difference.

9. The system for pairing cells for improved cycle life of claim 8, wherein, The control module preliminarily determines that the charge-discharge balance of the battery pack does not meet the requirements when the internal resistance difference of the electric cores in the battery pack is greater than the preset second internal resistance difference. The increase range of the dynamic characteristic weight coefficient is determined by the difference between the internal resistance difference of the electric cores in the battery pack and the preset first internal resistance difference. The control module determines that the charge-discharge balance of the battery pack meets the requirements when the attenuation rate of the available capacity of the battery pack is less than or equal to a preset attenuation rate. The control module determines that the charge-discharge balance of the battery pack is not qualified and increases the group matching correction value of the high-temperature cycle attenuation coefficient in response to the attenuation rate of the available capacity of the battery pack being greater than the preset attenuation rate.

10. The system for pairing cells for improved cycle life of claim 9, wherein, The increase range of the group matching correction value of the high-temperature cycle attenuation coefficient is determined by the difference between the attenuation rate of the available capacity of the battery pack and the preset attenuation rate.

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