A battery module and a manufacturing method thereof

Abstract

The present invention provides a battery module and a manufacturing method thereof. The manufacturing method of the battery module includes: providing a plurality of battery cells and obtaining an initial thickness of each of the plurality of battery cells; forming a first battery module, wherein the steps of forming the first battery module include: selecting a plurality of first battery cells from the plurality of battery cells and stacking them along a first direction to form a first initial battery module; using an extrusion plate to extrude the first initial battery module until the first initial battery module reaches a target length in the first direction; obtaining an extrusion force exerted by the extrusion plate on the first initial battery module when the first initial battery module reaches the target length; the extrusion force exerted by the extrusion plate on the first initial battery module is within a threshold range and the first initial battery module reaches the target length; and welding the first initial battery module to form the first battery module. Therefore, the manufacturing method of the battery module can improve the capacity and service life of the battery module.

Description

Technical Field

[0001] The present invention relates to the field of new energy technologies, and in particular to a battery module and a manufacturing method thereof. Background Art

[0002] Electric vehicles draw their energy from battery packs, which contain multiple modules, each of which is composed of multiple cells. However, in actual production, due to limitations in cell production technology, cell thickness tolerances are too wide, resulting in stacked modules that fail to meet required lengths. This impacts production, forcing the modules to be disassembled, leading to direct economic losses and capacity constraints.

[0003] The industry's solution to this problem is to measure the size of battery cells one by one, group the battery cells according to their thickness, and directly assemble them into battery modules after they are put into production. However, since there is no real-time test feedback on the extrusion pressure after the battery cells are stacked, the extrusion pressure of the battery module cannot be well controlled. The extrusion pressure between the battery cells will reduce the capacity and service life of the battery module. Therefore, it is necessary to provide a battery module manufacturing method to ensure that the length and extrusion pressure of the battery cells after stacking can meet the requirements. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that the extrusion pressure and length of the battery module formed after the battery cells are stacked do not have real-time test feedback, resulting in reduced capacity and service life of the battery module, thereby providing a battery module and a manufacturing method thereof.

[0005] In a first aspect, the present invention provides a method for manufacturing a battery module, comprising: step S1: providing a plurality of battery cells and obtaining an initial thickness of each of the plurality of battery cells; step S2: forming a first battery module, wherein the steps of forming the first battery module include: step S21: selecting a plurality of first battery cells from the plurality of battery cells and stacking them along a first direction to form a first initial battery module; step S22: using an extrusion plate to extrude the first initial battery module until the first initial battery module reaches a target length in the first direction; step S23: obtaining the extrusion force of the extrusion plate on the first initial battery module when the first initial battery module reaches the target length; step S24: when the extrusion force of the extrusion plate on the first initial battery module is not above a threshold value range, selecting several first replacement battery cells from several battery cells to replace part of the first battery cells in the first initial battery module; when the extrusion force of the extrusion plate on the first initial battery module is greater than the upper limit of the threshold range, the thickness of the first replacement battery cell is less than the thickness of the replaced first battery cell; when the extrusion force of the extrusion plate on the first initial battery module is less than the lower limit of the threshold range, the thickness of the first replacement battery cell is greater than the thickness of the replaced first battery cell; step S25: repeating steps S22 to S24 until the extrusion force of the extrusion plate on the first initial battery module is within the threshold range and the first initial battery module reaches the target length; step S26: after performing step S25, welding the first initial battery module to form a first battery module.

[0006] Optionally, step S1 further includes: dividing the plurality of battery cells into a plurality of battery cell groups, where different battery cell groups have different initial thickness ranges; in step S24, the battery cell group where the first replacement battery cell is located is different from the battery cell group where the replaced first battery cell is located.

[0007] Optionally, the step of dividing the plurality of battery cells into a plurality of battery cell groups includes: setting a code for each battery cell, corresponding the initial thickness of each battery cell to the code and recording it in a data processing system; dividing the battery cells into different battery cell groups according to the initial thicknesses of the plurality of battery cells and placing the battery cells on storage racks corresponding to each battery cell group.

[0008] Optionally, while obtaining the squeezing force of the squeezing plate on the first initial battery module, the initial thicknesses of the first battery cell and the first replacement battery cell in the first battery module are recorded and stored in a data processing system.

[0009] Optionally, it also includes: step S3: forming a second battery module; the steps of forming the second battery module include: step S31: selecting a plurality of second battery cells from the initial thickness range of the initial thickness of each of the first battery cell and the first replacement battery cell recorded in the data processing system; stacking the plurality of second battery cells to form a second initial battery module; step S32: using an extrusion plate to extrude the second initial battery module until the second initial battery module reaches a target length; step S33: obtaining the extrusion force of the extrusion plate on the second initial battery module when the second initial battery module reaches the target length; step S34: when the extrusion force of the extrusion plate on the second initial battery module is not within a threshold range, stacking the plurality of second battery cells from the plurality of battery cells. Selecting several second replacement battery cells from the cells to replace part of the second battery cells in the second initial battery module; when the extrusion force of the extrusion plate on the second initial battery module is greater than the upper limit of the threshold range, the thickness of the second replacement battery cell is less than the thickness of the replaced second battery cell; when the extrusion force of the extrusion plate on the second initial battery module is less than the lower limit of the threshold range, the thickness of the second replacement battery cell is greater than the thickness of the replaced second battery cell; step S35: repeating steps S32 to S34 until the extrusion force of the extrusion plate on the second initial battery module is within the threshold range and the second initial battery module reaches the target length; step S36: after performing step S35, welding the second initial battery module to form a second battery module.

[0010] Optionally, in step S31, the step of forming a second initial battery module also includes: selecting a plurality of second battery cells for stacking and setting a second buffer pad between adjacent second battery cells; and setting a second left clamping plate and a second right clamping plate on both sides of the stacking arrangement direction of the plurality of second battery cells.

[0011] Optionally, the extrusion force F2 of the extrusion plate on the second initial battery module is F 21 +F 22 +F 23 ; F 21 F is the sum of the extrusion forces exerted on the second replacement battery cell and the second battery cell in the second initial battery module; 22 is the sum of the extrusion forces on each second buffer pad; F 23 is the sum of the extrusion forces of the second left splint and the second right splint;

[0012] F 21 =(X 21 -X 21 ')ε 21 +(X 22 -X 22 ')ε 21 +……+(X 2N -X 2N ')ε 21 ;

[0013] F22 =(Y 21 -Y 21 ')ε 22 +(Y 22 -Y 22 ')ε 22 +……+(Y 2N -Y 2N ')ε 22 ;

[0014] F 23 =(Z 21 -Z 21 ')ε 23 +(Z 22 -Z 22 ')ε 23 ;

[0015] Among them, X 21 、X 22 ...X 2N is the initial thickness of the second replacement cell or the second cell, X 21 ', X 22 '..., X 2N ' is the thickness of the second replacement battery cell or the second battery cell after the extrusion plate extrudes the second initial battery module; Y 21 、Y 22 ...Y 2N is the initial thickness of each second cushion, Y 21 ', Y 22 '...Y 2N ' is the thickness of each second buffer pad after the extrusion plate extrudes the second initial battery module; Z 21 is the initial thickness of the second left splint, Z 22 is the initial thickness of the second right splint, Z 21 ' is the thickness of the second left clamping plate after the extrusion plate extrudes the second initial battery module, Z 22 ' is the thickness of the second right clamping plate after the extrusion plate extrudes the second initial battery module; ε 21 is the extrusion force coefficient of each cell in the second initial battery module; ε 22 is the extrusion force coefficient of the second buffer pad in the second initial battery module; 23is the extrusion pressure coefficient of the second left clamping plate or the second right clamping plate; after step S35, proceed to step S37: determine whether the absolute value of the first difference between the extrusion pressure F2 of the extrusion plate on the second initial battery module and the middle value of the threshold range is smaller than the absolute value of the second difference between the extrusion pressure F2 of the extrusion plate on the first initial battery module and the middle value of the threshold range; if the absolute value of the first difference is smaller than the absolute value of the second difference, execute step S36; if the absolute value of the first difference is greater than the absolute value of the second difference, reset the second replacement battery cell in the second initial battery module, and repeat steps S32 to S35 and S37 until the absolute value of the first difference is smaller than the absolute value of the second difference.

[0016] Optionally, after the extrusion plate extrudes the second initial battery module, the length L of the second initial battery module is L=X 21 '+X 22 '……X 2N '+Y 21 '+Y 22 '...Y 2N '+Z 21 '+Z 22 '.

[0017] Optionally, in step S21, the step of forming a first initial battery module also includes: selecting a plurality of first battery cells from the plurality of battery cells for stacking and setting a first buffer pad between adjacent first battery cells; and setting a first left clamping plate and a first right clamping plate on both sides of the stacking arrangement direction of the plurality of first battery cells.

[0018] Optionally, the step of using an extrusion plate to extrude the first initial battery module until the first initial battery module reaches a target length includes: using an extrusion plate to extrude the first left clamping plate and the first right clamping plate, a pressure sensor is provided on the extrusion plate, and the pressure sensor obtains the magnitude of the extrusion force of the extrusion plate on the clamping plate in real time.

[0019] In a second aspect, the present invention provides a battery module, which is manufactured by the above-mentioned battery module manufacturing method.

[0020] The technical solution of the present invention has the following advantages:

[0021] The present invention provides a method for manufacturing a battery module, which comprises selecting a plurality of first battery cells from the plurality of battery cells and stacking them along a first direction to form a first initial battery module; using an extrusion plate to extrude the first initial battery module until the first initial battery module reaches a target length in the first direction; obtaining the extrusion force of the extrusion plate on the first initial battery module when the first initial battery module reaches the target length; when the extrusion force of the extrusion plate on the first initial battery module is not within a threshold range, selecting a plurality of first replacement battery cells from the plurality of battery cells to replace part of the first battery cells in the first initial battery module until the extrusion force of the extrusion plate on the first initial battery module is within the threshold range and the first initial battery module reaches the target length; welding the first initial battery module to form a first battery module, wherein the first battery module not only meets the target length requirement, but also the extrusion force between the first battery cell and the first replacement battery cell in the first battery module is also within the specified extrusion force range, which can avoid the extrusion force in the first battery module from reducing the capacity and service life of the battery module. Therefore, the method for manufacturing a battery module can improve the capacity and service life of the battery module.

[0022] Furthermore, the plurality of battery cells are divided into a plurality of battery cell groups, and different battery cell groups have different initial thickness ranges. By measuring the thickness of a plurality of battery cells separately and then grouping the battery cells according to their initial thicknesses, it is beneficial to achieve the purpose of successfully stacking to form a battery module with the greatest probability when selecting battery cells, thereby improving the qualified rate and production efficiency of the battery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A flowchart of a method for manufacturing a battery module according to an embodiment of the present invention;

[0025] Figure 2 A schematic structural diagram of a method for manufacturing a battery module according to an embodiment of the present invention;

[0026] Figure 3 Schematic diagram of measuring the thickness of a battery cell at a testing station;

[0027] Figure 4 and Figure 5 A schematic diagram of performing appearance inspection on a battery cell according to an embodiment of the present invention;

[0028] Figure 6A schematic structural diagram of a gripping device provided in one embodiment of the present invention;

[0029] Figure 7 This is a statistical diagram of the lengths of several battery modules formed when the battery cells are not grouped;

[0030] Figure 8 The figure is a length statistical diagram of several battery modules formed by the battery module manufacturing method provided by the present invention. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0032] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0034] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] This embodiment provides a method for manufacturing a battery module. Figure 1 and Figure 2 , including the following steps:

[0036] Step S1: providing a plurality of battery cells 1 and obtaining the initial thickness of each of the battery cells;

[0037] Step S2: forming a first battery module 2. The steps of forming the first battery module 2 include:

[0038] Step S21: Selecting a plurality of first battery cells 11 from the plurality of battery cells 1 and stacking them along a first direction to form a first initial battery module;

[0039] Step S22: using an extrusion plate to extrude the first initial battery module until the first initial battery module reaches a target length in the first direction;

[0040] Step S23: obtaining the extrusion force of the extrusion plate on the first initial battery module when the first initial battery module reaches the target length;

[0041] Step S24: When the squeezing force of the squeezing plate on the first initial battery module is not within the threshold range, selecting a plurality of first replacement battery cells from the plurality of battery cells to replace some of the first battery cells in the first initial battery module; when the squeezing force of the squeezing plate on the first initial battery module is greater than the upper limit of the threshold range, the thickness of the first replacement battery cells is less than the thickness of the replaced first battery cells; when the squeezing force of the squeezing plate on the first initial battery module is less than the lower limit of the threshold range, the thickness of the first replacement battery cells is greater than the thickness of the replaced first battery cells;

[0042] Step S25: Repeat steps S22 to S24 until the extrusion force of the extrusion plate on the first initial battery module is within a threshold range and the first initial battery module reaches a target length;

[0043] Step S26: After step S25, the first initial battery module is welded to form a first battery module.

[0044] The present embodiment provides a method for manufacturing a battery module, which comprises selecting a plurality of first battery cells from the plurality of battery cells and stacking them along a first direction to form a first initial battery module; using an extrusion plate to extrude the first initial battery module until the first initial battery module reaches a target length in the first direction; obtaining the extrusion force of the extrusion plate on the first initial battery module when the first initial battery module reaches the target length; when the extrusion force of the extrusion plate on the first initial battery module is not within a threshold range, selecting a plurality of first replacement battery cells from the plurality of battery cells to replace some of the first battery cells in the first initial battery module until the extrusion force of the extrusion plate on the first initial battery module is within the threshold range and the first initial battery module reaches the target length; welding the first initial battery module to form a first battery module, wherein the first battery module not only meets the target length requirement, but also the extrusion force between the first battery cell and the first replacement battery cell in the first battery module is also within the specified extrusion force range, thereby preventing the extrusion force in the first battery module from reducing the capacity and service life of the battery module. Therefore, the method for manufacturing a battery module can improve the capacity and service life of the battery module.

[0045] In the present invention, the “first direction” refers to the thickness direction of the first battery cell.

[0046] In one embodiment, the threshold range is 1000N-3000N, for example, 1500N; if the threshold range is less than 1000N, the extrusion pressure in the first initial battery module is too small, and the degree of improvement in the stability of the first battery module structure is small; if the threshold range is greater than 3000N, the extrusion pressure in the first initial battery module is too large, and the degree of improvement in the capacity and service life of the first battery cell and the replacement battery cell in the first battery module is small.

[0047] In one embodiment, the threshold value range is 1400N-1500N. When the threshold value range is between 1400N-1500N, the capacity and service life of the battery cells in the battery module can reach optimal values.

[0048] In step S1, it also includes: referring to Figure 2 , the plurality of battery cells 1 are divided into a plurality of battery cell groups A, and different battery cell groups A have different initial thickness ranges.

[0049] refer to Figure 3 At the inspection station 3, by measuring the thickness of multiple battery cells 1 respectively, and then grouping the battery cells according to their initial thickness, it is beneficial to achieve the purpose of successfully stacking and forming a battery module with the greatest probability when selecting the battery cells, thereby improving the qualified rate of the battery module and the production efficiency.

[0050] In one embodiment, before dividing the plurality of battery cells into a plurality of battery cell groups, the process further includes: performing a visual inspection on the plurality of battery cells to select qualified battery cells. Specifically, a surface quality inspection is performed simultaneously on both sides of the battery cells in the thickness direction to detect whether the insulating film on the battery cell surface is damaged; and a visual inspection is performed on the two sides perpendicular to the thickness direction of the battery cells and the bottom surface of the battery cells. If the insulating film on the surface of the battery cell is damaged, the battery cell with the damaged insulating film is removed to an isolated area, which helps to improve the qualified rate of the battery module.

[0051] In one embodiment, in conjunction with reference Figure 4 and Figure 5 , performing appearance inspection on the plurality of battery cells includes performing appearance inspection using a 3D camera 4 .

[0052] In one embodiment, performing appearance inspection on the plurality of battery cells also includes obtaining the initial thickness of each of the plurality of battery cells, and feeding back the obtained battery cell thickness data to a data processing system.

[0053] In other embodiments, a contact-type displacement sensor may be used to obtain the initial thickness of each of the battery cells.

[0054] In one embodiment, the step of dividing the plurality of battery cells into a plurality of battery cell groups includes: setting a code for each battery cell, corresponding the initial thickness of each battery cell to the code and recording it in a data processing system; dividing the battery cells into different battery cell groups according to the initial thicknesses of the plurality of battery cells and placing the battery cells on storage racks corresponding to each battery cell group.

[0055] In one embodiment, the method further includes: obtaining position information of each first battery cell on the storage rack; selecting a plurality of first battery cells from the plurality of battery cells for stacking, referring to Figure 6 The data processing system controls the grabbing device to grab the first battery cell according to the position information of the first battery cell.

[0056] In step S21, the step of forming the first initial battery module also includes: selecting a plurality of first battery cells from the plurality of battery cells for stacking and setting a first buffer pad between adjacent first battery cells; and setting a first left clamping plate and a first right clamping plate on both sides of the stacking arrangement direction of the plurality of first battery cells.

[0057] In one embodiment, the step of using an extrusion plate to extrude the first initial battery module until the first initial battery module reaches a target length includes: using an extrusion plate to extrude the first left clamping plate and the first right clamping plate, wherein a pressure sensor is provided on the extrusion plate, and the pressure sensor obtains the magnitude of the extrusion force of the extrusion plate on the clamping plate in real time.

[0058] In step S24, the cell group in which the first replacement cell is located is different from the cell group in which the first cell being replaced is located. Specifically, when the squeezing force of the squeezing plate on the first initial battery module is greater than the upper limit of the threshold range, the thickness range of the cell group in which the first replacement cell is located is smaller than the thickness range of the cell group in which the first cell being replaced is located; and when the squeezing force of the squeezing plate on the first initial battery module is less than the lower limit of the threshold range, the thickness range of the cell group in which the first replacement cell is located is larger than the thickness range of the cell group in which the first cell being replaced is located.

[0059] In one embodiment, the compression force exerted by the compression plate on the first initial battery module is obtained, and at the same time, the initial thicknesses of the first battery cell and the first replacement battery cell in the first battery module are recorded and stored in a data processing system.

[0060] In one embodiment, the pressing force F1 of the pressing plate on the first initial battery module is F 11 +F 12 +F 13 ; F 11 F is the sum of the extrusion forces exerted on the first replacement battery cell and the first battery cell in the first initial battery module; 12 is the sum of the extrusion forces on each first buffer pad; F 13is the sum of the extrusion forces of the first left splint and the first right splint;

[0061] F 11 =(X 11 -X 11 ')ε 11 +(X 12 -X 12 ')ε 11 +……+(X 1N -X 1N ')ε 11 ;

[0062] F 12 =(Y 11 -Y 11 ')ε 12 +(Y 12 -Y 12 ')ε 12 +……+(Y 1N -Y 1N ')ε 12 ;

[0063] F 13 =(Z 11 -Z 11 ')ε 13 +(Z 12 -Z 12 ')ε 13 ;

[0064] Among them, X 11 、X 12 ...X 1N is the initial thickness of the first replacement cell or the first cell, X 11 ', X 12 '..., X 1N ' is the thickness of the first replacement battery cell or the first battery cell after the extrusion plate extrudes the first initial battery module; Y 11 、Y 12 ...Y 1N is the initial thickness of each first cushion, Y 11 ', Y 12 '...Y 1N ' is the thickness of each first buffer pad after the extrusion plate extrudes the first initial battery module; Z 11 is the initial thickness of the first left splint, Z 12 is the initial thickness of the first right splint, Z 11 ' is the thickness of the first left clamping plate after the extrusion plate extrudes the first initial battery module, Z 12 ' is the thickness of the first right clamping plate after the extrusion plate extrudes the first initial battery module; ε 11 is the extrusion force coefficient of each cell in the first initial battery module;12 is the extrusion force coefficient of the first buffer pad in the first initial battery module; 13 is the extrusion force coefficient of the first left clamping plate or the first right clamping plate; after step 25, proceed to step 27: determine whether the absolute value of a first difference between the extrusion force F1 of the extrusion plate on the first initial battery module and the middle value of the threshold range is less than the absolute value of a second difference between the extrusion force F1 of the extrusion plate on the first initial battery module and the middle value of the threshold range;

[0065] If the absolute value of the first difference is smaller than the absolute value of the second difference, step S26 is executed;

[0066] If the absolute value of the first difference is greater than the absolute value of the second difference, the first replacement cell in the first initial battery module is reset, and steps S22 to S25 and S27 are repeated until the absolute value of the first difference is less than the absolute value of the second difference.

[0067] In one embodiment, the length L of the first initial battery module after the first initial battery module is pressed by the pressing plate is L=X 11 '+X 12 '……X 1N '+Y 11 '+Y 12 '...Y 1N '+Z 11 '+Z 12 '.

[0068] In one embodiment, the method further includes: step S3: forming a second battery module; the steps of forming the second battery module include:

[0069] Step S31: selecting a plurality of second battery cells from the initial thickness ranges of the initial thicknesses of the first battery cell and the first replacement battery cell recorded in the data processing system; and stacking the plurality of second battery cells to form a second initial battery module.

[0070] Step S32: using an extrusion plate to extrude the second initial battery module until the second initial battery module reaches a target length;

[0071] Step S33: obtaining the extrusion force of the extrusion plate on the second initial battery module when the second initial battery module reaches the target length;

[0072] Step S34: when the squeezing force of the squeezing plate on the second initial battery module is not within the threshold range, selecting a plurality of second replacement battery cells from the plurality of battery cells to replace some of the second battery cells in the second initial battery module; when the squeezing force of the squeezing plate on the second initial battery module is greater than the upper limit of the threshold range, the thickness of the second replacement battery cells is less than the thickness of the replaced second battery cells; when the squeezing force of the squeezing plate on the second initial battery module is less than the lower limit of the threshold range, the thickness of the second replacement battery cells is greater than the thickness of the replaced second battery cells;

[0073] Step S35: Repeat steps S32 to S34 until the squeezing force of the squeezing plate on the second initial battery module is within a threshold range and the second initial battery module reaches a target length;

[0074] Step S36: After step S35, the second initial battery module is welded to form a second battery module.

[0075] In one embodiment, the step of forming the second initial battery module also includes: selecting a plurality of second battery cells for stacking and setting a second buffer pad between adjacent second battery cells; and setting a second left clamping plate and a second right clamping plate on both sides of the stacking arrangement direction of the plurality of second battery cells.

[0076] In one embodiment, the pressing force F2 of the pressing plate on the second initial battery module is F 21 +F 22 +F 23 ; F 21 F is the sum of the extrusion forces exerted on the second replacement battery cell and the second battery cell in the second initial battery module; 22 is the sum of the extrusion forces on each second buffer pad; F 23 is the sum of the extrusion forces of the second left splint and the second right splint;

[0077] F 21 =(X 21 -X 21 ')ε 21 +(X 22 -X 22 ')ε 21 +……+(X 2N -X 2N ')ε 21 ;

[0078] F 22 =(Y 21 -Y 21 ')ε 22 +(Y 22 -Y 22 ')ε 22 +……+(Y 2N -Y 2N ')ε22 ;

[0079] F 23 =(Z 21 -Z 21 ')ε 23 +(Z 22 -Z 22 ')ε 23 ;

[0080] Among them, X 21 、X 22 ...X 2N is the initial thickness of the second replacement cell or the second cell, X 21 ', X 22 '..., X 2N ' is the thickness of the second replacement battery cell or the second battery cell after the extrusion plate extrudes the second initial battery module; Y 21 、Y 22 ...Y 2N is the initial thickness of each second cushion, Y 21 ', Y 22 '...Y 2N ' is the thickness of each second buffer pad after the extrusion plate extrudes the second initial battery module; Z 21 is the initial thickness of the second left splint, Z 22 is the initial thickness of the second right splint, Z 21 ' is the thickness of the second left clamping plate after the extrusion plate extrudes the second initial battery module, Z 22 ' is the thickness of the second right clamping plate after the extrusion plate extrudes the second initial battery module; ε 21 is the extrusion force coefficient of each cell in the second initial battery module; ε 22 is the extrusion force coefficient of the second buffer pad in the second initial battery module; 23 is the extrusion pressure coefficient of the second left clamping plate or the second right clamping plate; after step S35, proceed to step S37: determine whether the absolute value of the first difference between the extrusion pressure F2 of the extrusion plate on the second initial battery module and the middle value of the threshold range is smaller than the absolute value of the second difference between the extrusion pressure F2 of the extrusion plate on the first initial battery module and the middle value of the threshold range; if the absolute value of the first difference is smaller than the absolute value of the second difference, execute step S36; if the absolute value of the first difference is greater than the absolute value of the second difference, reset the second replacement battery cell in the second initial battery module, and repeat steps S32 to S35 and S37 until the absolute value of the first difference is smaller than the absolute value of the second difference.

[0081] In one embodiment, F 21 =(X 21 -X 21 ')ε 21 +(X22 -X 22 ')ε 21 +……+(X 2N –X 2N ')ε 21 =(12.25mm-12.17mm)*1500N / mm+(12.26mm-12.17mm)*1500N / mm+(12.14mm-12.17mm)*1500N / mm+(12.25mm-12.17mm)*1500N / mm+(12.24mm-12.17mm)*1500N / mm+(12.23mm-12.17mm)*1500N / mm+(12.12mm-12.17mm)*1500N / mm+(12.19mm-12.17mm)*1500N / mm+(12.26mm-12.17mm)*1500N / mm+(12.18mm-12.17mm)*1500N / mm+(12.17mm-12.17mm)*1500N / mm+(12.25mm-12.17mm)*1500N / mm+(12.26mm-12.17mm)*1500N / mm+(12.18mm-12.17mm)*1500N / mm+(12.14mm-12.17mm)*1500N / mm+(12.24mm-12.17mm)*1500N / mm+(12.23mm-12.17mm)*1500N / mm+(12.12mm-12.17mm)*1500N / mm+(12.27mm-12.17mm)*1500N / mm+(12.19mm-12.17mm)*1500N / mm+(12.26mm-12.17mm)*1500N / mm+(12.17mm-12.17mm)*1500N / mm+(12.27mm-12.17mm)*1500N / mm+(12.25mm-12.17mm)*1500N / mm=1560N;

[0082] F 22 =(Y 21 -Y 21 ')ε 22 +(Y 22 -Y 22 ')ε 22 +……+(Y 2N -Y 2N ')ε 22=(1.1mm-1.02mm)*100N / mm+(1.1mm-0.99mm)*100N / mm+(1.1mm-0.99mm)*100N / mm+(1.1mm-1.0mm)*100N / mm+(1.1mm-1.01mm)*100N / mm+(1.1mm-1.02mm)*10 0N / mm+(1.1mm-0.99mm)*100N / mm+(1.1mm-1.01mm)*100N / mm+(1.1mm-0.99mm) *100N / mm+(1.1mm-1.0mm)*100N / mm+(1.1mm-1.02mm)*100N / mm+(1.1mm-0.99m m)*10N / mm+(1.1mm-0.99mm)*100N / mm+(1.1mm-1.0mm)*100N / mm+(1.1mm-1.0m m)*100N / mm+(1.1mm-1.01mm)*100N / mm+(1.1mm-1.02mm)*100N / mm+(1.1mm-1. 0mm)*100N / mm+(1.1mm-0.99mm)*100N / mm+(1.1mm-1.01mm)*100N / mm+(1.1mm- 0.99mm)*100N / mm+(1.1mm-1.0mm)*100N / mm+(1.1mm-0.99mm)*100N / mm=227N;

[0083] F 23 =(Z 21 -Z 21 ')ε 23 +(Z 22 -Z 22 ')ε 23 =(16mm-15.98mm)*2250N / mm+(16mm-15.99mm)*2250N / mm=67.5N;

[0084] F2=F 21 +F 22 +F 23 =1560N+227N+67.5N=1854.5N.

[0085] In one embodiment, the length L of the second initial battery module after the extrusion plate extrudes the second initial battery module is L=X 21 '+X 22 '……X 2N '+Y 21 '+Y 22 '...Y 2N '+Z 21 '+Z22 '.

[0086] In one embodiment, the method further includes: forming an Nth battery module, where N is an integer equal to or greater than 3, and the step of forming a kth battery module includes: selecting a plurality of kth battery cells from the first battery cell and the first replacement battery cell, or the second battery cell and the second replacement battery cell, or the jth battery cell and the jth replacement battery cell recorded in the data processing system; stacking the plurality of kth battery cells to form a kth initial battery module; and welding the kth initial battery module to form the kth battery module after the compression force exerted by the compression plate on the kth initial battery module is within a threshold range and the kth initial battery module reaches a target length. j is an integer equal to or greater than 3 and less than or equal to N-1, and k is an integer greater than j and less than or equal to N.

[0087] In one embodiment, the thickness combination of the cells in the kth battery module is better than the thickness combination of the cells in the k-1th battery module. The cells in the kth battery module are selected based on the thickness of the cells in the k-1th battery module recorded in the data processing system.

[0088] Combined with reference Figure 7 and Figure 8 , Figure 7 and Figure 8 The horizontal axis represents the length distribution interval of the battery module, the vertical axis represents the number of battery modules in the corresponding interval, the area between the two dotted lines is the qualified interval of the battery module length, and the solid line is the target length of the battery module. Figure 7 A battery module that does not include multiple battery cells grouped together; Figure 8 Several battery modules are stacked using the battery module manufacturing method provided by this embodiment. It can be seen that the lengths of the battery modules formed without grouping the battery cells are relatively scattered and there are unqualified battery modules. Several battery modules are stacked using the battery module manufacturing method provided by this embodiment have better length consistency, the length distribution of the battery modules is more concentrated, and the qualified rate of the battery modules is high.

[0089] The present invention also provides a battery module, which is manufactured by the above-mentioned battery module manufacturing method.

[0090] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for manufacturing a battery module, characterized in that: include: Step S1: providing a plurality of battery cells and obtaining the initial thickness of each of the plurality of battery cells; Step S2: forming a first battery module. The steps of forming the first battery module include: Step S21: selecting a plurality of first battery cells from the plurality of battery cells and stacking them along a first direction to form a first initial battery module; Step S22: using an extrusion plate to extrude the first initial battery module until the first initial battery module reaches a target length in the first direction; Step S23: obtaining the extrusion force of the extrusion plate on the first initial battery module when the first initial battery module reaches the target length; Step S24: When the squeezing force of the squeezing plate on the first initial battery module is not within the threshold range, selecting a plurality of first replacement battery cells from the plurality of battery cells to replace some of the first battery cells in the first initial battery module; when the squeezing force of the squeezing plate on the first initial battery module is greater than the upper limit of the threshold range, the thickness of the first replacement battery cells is less than the thickness of the replaced first battery cells; when the squeezing force of the squeezing plate on the first initial battery module is less than the lower limit of the threshold range, the thickness of the first replacement battery cells is greater than the thickness of the replaced first battery cells; Step S25: Repeat steps S22 to S24 until the squeezing force of the squeezing plate on the first initial battery module is within a threshold range and the first initial battery module reaches a target length; Step S26: After step S25, the first initial battery module is welded to form a first battery module.

2. The method for manufacturing a battery module according to claim 1, wherein: Step S1 further includes: dividing the plurality of battery cells into a plurality of battery cell groups, wherein different battery cell groups have different initial thickness ranges; In step S24 , the battery cell group in which the first replacement battery cell is located is different from the battery cell group in which the first battery cell to be replaced is located.

3. The method for manufacturing a battery module according to claim 2, wherein: The step of dividing the plurality of battery cells into a plurality of battery cell groups includes: setting a code for each battery cell, corresponding the initial thickness of each battery cell to the code and recording it in a data processing system; dividing the battery cells into different battery cell groups according to the initial thickness of the plurality of battery cells and placing the battery cells on storage racks corresponding to each battery cell group.

4. The method for manufacturing a battery module according to claim 1, wherein: The extrusion force exerted by the extrusion plate on the first initial battery module is obtained, and the initial thicknesses of the first battery cell and the first replacement battery cell in the first battery module are recorded and stored in a data processing system.

5. The method for manufacturing a battery module according to claim 4, wherein: The method further includes: step S3: forming a second battery module; The steps of forming the second battery module include: Step S31: selecting a plurality of second battery cells from the initial thickness ranges of the initial thicknesses of the first battery cell and the first replacement battery cell recorded in the data processing system; and stacking the plurality of second battery cells to form a second initial battery module. Step S32: using an extrusion plate to extrude the second initial battery module until the second initial battery module reaches a target length; Step S33: obtaining the extrusion force of the extrusion plate on the second initial battery module when the second initial battery module reaches the target length; Step S34: when the squeezing force of the squeezing plate on the second initial battery module is not within the threshold range, selecting a plurality of second replacement battery cells from the plurality of battery cells to replace some of the second battery cells in the second initial battery module; when the squeezing force of the squeezing plate on the second initial battery module is greater than the upper limit of the threshold range, the thickness of the second replacement battery cells is less than the thickness of the replaced second battery cells; when the squeezing force of the squeezing plate on the second initial battery module is less than the lower limit of the threshold range, the thickness of the second replacement battery cells is greater than the thickness of the replaced second battery cells; Step S35: Repeat steps S32 to S34 until the squeezing force of the squeezing plate on the second initial battery module is within a threshold range and the second initial battery module reaches a target length; Step S36: After step S35, the second initial battery module is welded to form a second battery module.

6. The method for manufacturing a battery module according to claim 5, wherein: In step S31, the step of forming the second initial battery module also includes: selecting a plurality of second battery cells for stacking and setting a second buffer pad between adjacent second battery cells; and setting a second left clamping plate and a second right clamping plate on both sides of the stacking arrangement direction of the plurality of second battery cells.

7. The method for manufacturing a battery module according to claim 6, wherein: The extrusion force F2 of the extrusion plate on the second initial battery module is F 21 +F 22 +F 23 ; F 21 F is the sum of the extrusion forces exerted on the second replacement battery cell and the second battery cell in the second initial battery module; 22 is the sum of the extrusion forces on each second buffer pad; F 23 is the sum of the extrusion forces of the second left splint and the second right splint; F 21 =(X 21 -X 21 ')ε 21 +(X 22 -X 22 ')ε 21 +……+(X 2N -X 2N ')ε 21 ; F 22 =(And 21 -AND 21 ')ε 22 +(And 22 -AND 22 ')ε 22 +……+(And 2N -AND 2N ')ε 22 ; F 23 =(Z 21 -WITH 21 ')ε 23 +(Z 22 -WITH 22 ')ε 23 ; Among them, X 21 、X 22 ...X 2N is the initial thickness of the second replacement cell or the second cell, X 21 ', X 22 '..., X 2N ' is the thickness of the second replacement battery cell or the second battery cell after the extrusion plate extrudes the second initial battery module; Y 21 、Y 22 ...Y 2N is the initial thickness of each second cushion, Y 21 ', Y 22 '...Y 2N ' is the thickness of each second buffer pad after the extrusion plate extrudes the second initial battery module; Z 21 is the initial thickness of the second left splint, Z 22 is the initial thickness of the second right splint, Z 21 ' is the thickness of the second left clamping plate after the extrusion plate extrudes the second initial battery module, Z 22 ' is the thickness of the second right clamping plate after the extrusion plate extrudes the second initial battery module; ε 21 is the extrusion force coefficient of each cell in the second initial battery module; ε 22 is the extrusion force coefficient of the second buffer pad in the second initial battery module; 23 is the extrusion force coefficient of the second left splint or the second right splint; After step S35, proceed to step S37: determine whether the absolute value of a first difference between the squeezing force F2 of the squeezing plate on the second initial battery module and the middle value of the threshold range is less than the absolute value of a second difference between the squeezing force F2 of the squeezing plate on the first initial battery module and the middle value of the threshold range; If the absolute value of the first difference is smaller than the absolute value of the second difference, step S36 is executed; If the absolute value of the first difference is greater than the absolute value of the second difference, the second replacement cell in the second initial battery module is reset, and steps S32 to S35 and S37 are repeated until the absolute value of the first difference is less than the absolute value of the second difference.

8. The method for manufacturing a battery module according to claim 7, wherein: The length L of the second initial battery module after the extrusion plate extrudes the second initial battery module is =X 21 '+X 22 '……X 2N '+Y 21 '+Y 22 '...Y 2N '+Z 21 '+Z 22 '.

9. The method for manufacturing a battery module according to claim 1, wherein: In step S21, the step of forming the first initial battery module also includes: selecting a plurality of first battery cells from the plurality of battery cells for stacking and setting a first buffer pad between adjacent first battery cells; and setting a first left clamping plate and a first right clamping plate on both sides of the stacking arrangement direction of the plurality of first battery cells.

10. A battery module, characterized in that: The battery module is manufactured by the battery module manufacturing method according to any one of claims 1 to 9.

Images