Battery module and battery pack

Abstract

A battery module, comprising a busbar and a plurality of battery cells. Each battery cell comprises an electrode assembly, a cover plate module, and a housing body having a single-sided opening. The cover plate assembly is disposed at the opening of the housing body, and the cover plate module and the housing body together form an accommodating cavity for accommodating the electrode assembly. The cover plate module is provided with an electrode terminal welded to the busbar, and the effective area between the busbar and the electrode terminal during welding is determined according to the following formula (I).

Description

Battery modules and battery packs

[0001] This application claims priority to Chinese patent applications filed on March 14, 2025, with application numbers 202510304218.4 and 202510303810.2, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, such as a battery module and battery pack. Background Technology

[0003] Lithium-ion batteries are a new type of high-energy battery based on the movement of lithium ions between the positive and negative electrodes. During charging, lithium ions are extracted from the positive electrode and inserted into the negative electrode through the electrolyte; during discharging, the reverse occurs, with lithium ions being extracted from the negative electrode and returning to the positive electrode, forming current to power devices. Due to their advantages such as high energy density, high voltage, wide operating temperature range, and long shelf life, lithium-ion batteries have a wide range of applications, including electric vehicles, energy storage systems, and military equipment. With continuous development, lithium-ion batteries have evolved into various types, such as blade batteries, prismatic batteries, and large cylindrical batteries.

[0004] Among them, the battery strip is welded to the terminal blocks on multiple individual cells to form a battery module with higher capacity. The effective welding area of ​​the battery strip and the terminal blocks needs to meet the overcurrent requirements of the individual cells. Otherwise, overheating will occur at the solder joint, which will affect the cycle performance of the battery and require a higher cooling level within the module, which is not conducive to cost reduction.

[0005] When calculating the effective area of ​​the electrode plate and terminal block in the battery module, it is necessary to rely on the capacity of the individual battery cell. However, the capacity calculation of a conventional individual battery cell is very complicated and requires the calculation of multiple parameters, such as the specific capacity of the material, compaction density, areal density, active material ratio, and electrode coating area. As a result, the calculation of the effective area of ​​the electrode plate and terminal block in the battery module is difficult and the calculation cycle is long. Summary of the Invention

[0006] This application provides a battery module, which includes a battery plate and multiple individual cells. Each individual cell includes an electrode assembly, a cover plate module, and a housing body with an opening on one side. The cover plate module is disposed at the opening of the housing body, and the cover plate module and the housing body form a receiving cavity for accommodating the electrode assembly. The cover plate module is provided with terminal posts that are welded to the battery plate. The effective area of ​​the battery plate when welded to the terminal post is determined according to the following formula: ;

[0007] In the formula:

[0008] S represents the effective area when the electrode plate is welded to the terminal block, in mm. 2 ;

[0009] U is the spatial dimension of the receiving cavity along the first direction, in mm;

[0010] V is the spatial dimension of the receiving cavity along the second direction, in mm;

[0011] W represents the spatial dimension of the receiving cavity along a third direction, in mm;

[0012] x is the gap coefficient of the pole group along the second direction, in mm;

[0013] y is the gap coefficient of the pole group along the first direction, in mm;

[0014] δ represents the capacity coefficient of the individual battery cell, with units of Ah / mm². 3 ;

[0015] A represents the charge / discharge rate of the individual battery cell;

[0016] 7 represents the current coefficient for welding the electrode plate to the terminal block, in Ah / mm. 2 .

[0017] Optionally, the cover module includes a first surface facing away from the electrode assembly and a second surface abutting against the electrode assembly, the outer shell body includes a first wall surface opposite to the opening, and the spatial dimension U of the receiving cavity along the first direction is determined according to the following formula: ;

[0018] In the formula:

[0019] H is the dimension of the outer shell body along the first direction, in mm;

[0020] 'a' represents the distance between the first surface and the second surface along the first direction, in mm.

[0021] J represents the thickness of the first wall surface, in mm.

[0022] Optionally, the outer shell body includes two second walls disposed opposite each other along the second direction, and the spatial dimension V of the receiving cavity along the second direction is determined according to the following formula:

[0023] ;

[0024] In the formula:

[0025] L is the dimension of the outer shell body along the second direction, in mm;

[0026] I1 is the thickness dimension of one of the two second wall surfaces, in mm;

[0027] I2 is the thickness dimension of the other of the two second wall surfaces, in mm.

[0028] Optionally, the outer shell body includes two third walls disposed opposite each other along the third direction, and the spatial dimension W of the receiving cavity along the third direction is determined according to the following formula:

[0029] ;

[0030] In the formula:

[0031] T represents the dimension of the outer shell body along the third direction, in mm;

[0032] M1 is the thickness dimension of one of the two third wall surfaces, in mm;

[0033] M2 is the thickness dimension of the other of the two third wall surfaces, in mm.

[0034] Optionally, the gap coefficient x of the electrode group along the second direction satisfies 5mm≤x≤8mm.

[0035] Optionally, the gap coefficient y of the electrode group along the first direction satisfies 5mm≤y≤10mm.

[0036] Optionally, in the lithium iron phosphate system, the capacity coefficient δ of the single cell satisfies... .

[0037] Optionally, in a ternary system, the capacity coefficient δ of the single cell satisfies... .

[0038] Optionally, the second wall surface has a placement groove for accommodating the cover module on one side of the opening of the outer casing.

[0039] This application provides a battery pack, which includes an electrical connection structure and a plurality of battery modules as described above. The plurality of battery modules are arranged sequentially and connected to each other, and the electrical connection structure is electrically connected to the plurality of battery modules.

[0040] This application also provides a battery module, which includes a battery plate and multiple individual cells. Each individual cell includes an electrode assembly, a first cover plate module, a second cover plate module, and a housing body with openings on both sides. The first cover plate module and the second cover plate module are respectively disposed at the openings of the housing body to form a receiving cavity for accommodating the electrode assembly. Both the first cover plate module and the second cover plate module are provided with terminal posts welded to the battery plate. The effective area of ​​the battery plate when welded to each terminal post is determined according to the following formula: ;

[0041] In the formula:

[0042] S represents the effective area when the electrode plate is welded to the terminal block, in mm. 2 ;

[0043] U is the spatial dimension of the receiving cavity along the first direction, in mm;

[0044] V is the spatial dimension of the receiving cavity along the second direction, in mm;

[0045] W represents the spatial dimension of the receiving cavity along a third direction, in mm;

[0046] x is the gap coefficient of the pole group along the first direction, in mm;

[0047] y is the gap coefficient of the pole group along the second direction, in mm;

[0048] δ represents the capacity coefficient of the individual battery cell, with units of Ah / mm². 3 ;

[0049] A represents the charge / discharge rate of the individual battery cell;

[0050] 7 represents the current coefficient for welding the electrode plate to the terminal block, in Ah / mm. 2 .

[0051] Optionally, the first cover module includes a first surface facing away from the electrode group, a second surface abutting against the electrode group, and a third surface abutting against the outer shell body; the second cover module includes a fourth surface facing away from the electrode group, a fifth surface abutting against the electrode group, and a sixth surface abutting against the outer shell body; the spatial dimension U of the receiving cavity along the first direction is determined according to the following formula: ;

[0052] In the formula:

[0053] L is the dimension of the outer shell body along the first direction, in mm;

[0054] a1 is the distance between the first surface and the second surface along the first direction, in mm;

[0055] b1 is the distance between the first surface and the third surface along the first direction, in mm;

[0056] a2 is the distance between the fourth surface and the fifth surface along the first direction, in mm;

[0057] b2 is the distance between the fourth surface and the sixth surface along the first direction, in mm.

[0058] Optionally, the outer shell body includes a first wall and a fourth wall disposed opposite to each other along the second direction, and the spatial dimension V of the receiving cavity along the second direction is determined according to the following formula: ;

[0059] In the formula:

[0060] H is the dimension of the outer shell body along the second direction, in mm;

[0061] t1 is the thickness of the first wall surface, in mm;

[0062] t4 is the thickness of the fourth wall surface, in mm.

[0063] Optionally, the outer shell body includes a second wall and a third wall disposed opposite to each other along the third direction, and the spatial dimension W of the receiving cavity along the third direction is determined according to the following formula:

[0064] ;

[0065] In the formula:

[0066] T represents the dimension of the outer shell body along the third direction, in mm;

[0067] t2 is the thickness of the second wall surface, in mm;

[0068] t3 is the thickness of the third wall surface, in mm.

[0069] Optionally, the gap coefficient x of the electrode group along the first direction satisfies 8mm≤x≤12mm.

[0070] Optionally, the gap coefficient y of the pole group along the second direction satisfies 6mm≤y≤9mm.

[0071] Optionally, in the lithium iron phosphate system, the capacity coefficient δ of the single cell satisfies... .

[0072] Optionally, in a ternary system, the capacity coefficient δ of the single cell satisfies... .

[0073] Optionally, the distance b1 between the first surface and the third surface along the first direction satisfies b1≥0.5mm;

[0074] And / or, the distance b2 between the fourth surface and the sixth surface along the first direction satisfies b2≥0.5mm.

[0075] This application also provides a battery pack, which includes an electrical connection structure and a plurality of battery modules as described above, wherein the plurality of battery modules are arranged sequentially and connected to each other, and the electrical connection structure is electrically connected to the plurality of battery modules. Attached Figure Description

[0076] Figure 1 is a schematic diagram of the welding structure of the foil and the single cell provided in the embodiment of this application;

[0077] Figure 2 is an enlarged view of the structure of part I in Figure 1;

[0078] Figure 3 is an exploded view of the structure of a single battery provided in an embodiment of this application;

[0079] Figure 4 is a structural cross-sectional view of a single battery provided in an embodiment of this application;

[0080] Figure 5 is an enlarged view of the structure of part I in Figure 4;

[0081] Figure 6 is an isometric view of the outer casing of a single battery provided in an embodiment of this application;

[0082] Figure 7 is an enlarged view of the structure of part II in Figure 6;

[0083] Figure 8 is a front cross-sectional view of the outer casing of a single battery provided in an embodiment of this application;

[0084] Figure 9 is a side cross-sectional view of the outer casing of a single battery provided in an embodiment of this application;

[0085] Figure 10 is an exploded view of the structure of a single battery provided in an embodiment of this application;

[0086] Figure 11 is a structural cross-sectional view of a single battery provided in an embodiment of this application;

[0087] Figure 12 is an enlarged view of the structure of part II in Figure 11;

[0088] Figure 13 is an enlarged view of the structure of part III in Figure 11;

[0089] Figure 14 is a three-dimensional structural diagram of the outer casing of a single battery provided in an embodiment of this application;

[0090] Figure 15 is a planar projection view of the outer casing of a single battery provided in an embodiment of this application along a first direction. Detailed Implementation

[0091] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit its scope. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present application, not the entire structure.

[0092] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0093] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0094] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0095] Calculating the effective area of ​​the electrode plate and terminal block welding in the battery module requires calculation based on the capacity of the individual cells. However, the capacity calculation of a conventional individual cell is very complicated, requiring the calculation of multiple parameters, such as the specific capacity of the material, compaction density, areal density, active material ratio, and electrode coating area. This makes the calculation of the effective area of ​​the electrode plate and terminal block welding in the battery module difficult and time-consuming.

[0096] Example A

[0097] As shown in Figures 1 to 9, the battery module includes a battery pack 1 and multiple individual cells 2. Each individual cell 2 includes an electrode assembly 21, a cover module 22, and a housing body 23 with an opening on one side. The cover module 22 is located at the opening of the housing body 23 and forms a cavity 24 for accommodating the electrode assembly 21 together with the housing body 23. The cover module 22 is provided with terminal posts that are welded to the battery pack 1. The effective area of ​​the battery pack 1 when welded to the terminal post is determined according to the following formula: ;

[0098] In the formula:

[0099] S represents the effective area when the electrode plate 1 is welded to the terminal block, in mm. 2 ;

[0100] U is the spatial dimension of the receiving cavity 24 along the first direction, in mm;

[0101] V is the spatial dimension of the receiving cavity 24 along the second direction, in mm;

[0102] W represents the spatial dimension of the receiving cavity 24 along the third direction, in mm;

[0103] x is the gap coefficient of pole group 21 along the second direction, in mm;

[0104] y is the gap coefficient of pole group 21 along the first direction, in mm;

[0105] δ is the capacity coefficient of cell 2, in Ah / mm². 3 ;

[0106] A represents the charge / discharge rate of cell 2;

[0107] 7 represents the current coefficient for welding the electrode plate 1 to the terminal block, in Ah / mm. 2 .

[0108] Through formula When calculating the lower limit of the effective area when welding the battery module's battery plate to the terminal block, it is only necessary to use the spatial dimensions of the receiving cavity, namely the spatial dimensions U of the receiving cavity along the first direction, the spatial dimensions V of the receiving cavity along the second direction, and the spatial dimensions W of the receiving cavity along the third direction, combined with the charge / discharge rate A and the capacity coefficient δ of the individual battery. There is no need to calculate the capacity of the individual battery separately, thereby reducing the parameters that need to be calculated, reducing the difficulty of the calculation, improving the calculation speed, and shortening the calculation cycle.

[0109] In this embodiment, since batteries of different sizes have different charge / discharge rates A, when calculating the charge / discharge rate A of a single battery 2, the time Z required for the current single battery 2 to be fully charged is first determined, in minutes; then, the charge / discharge rate A of the current single battery 2 is obtained by calculating according to the formula A=60min / Z.

[0110] Since the material of the electrode plate 1 is aluminum, and the electrode plate 1 is welded to the terminal of the electrode plate outside the single cell 2, the overcurrent coefficient in the calculation formula is determined to be 7 according to the national standard. In addition, as shown in Figures 1 and 2, the welding trajectory of the electrode plate 1 and the terminal of the electrode plate can be set to form a strip weld mark 100, a circular weld mark 200 or a square weld mark 300, etc. It is only necessary to ensure that the effective area after welding meets the calculation requirements.

[0111] Optionally, as shown in Figures 5 and 8, the cover module 22 includes a first surface 221 facing away from the electrode group 21 and a second surface 222 abutting against the electrode group 21, the outer shell body 23 includes a first wall surface 231 opposite to the opening, and the spatial dimension U of the receiving cavity 24 along the first direction is determined according to the following formula: ;

[0112] In the formula:

[0113] H is the dimension of the outer shell 23 along the first direction, in mm;

[0114] a is the distance between the first surface 221 and the second surface 222 along the first direction, in mm;

[0115] The thickness of the first wall surface 231 is measured in mm.

[0116] By determining the dimension H of the outer shell body 23 along the first direction, the spacing a of the first surface 221 and the second surface 222 of the cover module 22 along the first direction, and the thickness J of the first wall surface 231, the spatial dimension U of the receiving cavity 24 along the first direction can be obtained more intuitively through the above structural parameters, reducing the difficulty of determining the spatial dimension U of the receiving cavity 24 along the first direction.

[0117] In this embodiment, the cover plate module 22 includes a cover plate body 223 and an inner insulating member 224. The inner insulating member 224 is connected to the side of the cover plate body 223 facing the opening of the outer shell body 23 and abuts against the pole group 21. The surface of the cover plate body 223 facing away from the pole group 21 is the first surface 221, and the surface of the inner insulating member 224 abutting against the pole group 21 is the second surface 222.

[0118] Optionally, as shown in FIG8, the outer shell body 23 includes two second walls 232 disposed opposite to each other along the second direction, and the spatial dimension V of the receiving cavity 24 along the second direction is determined according to the following formula: ;

[0119] In the formula:

[0120] L is the dimension of the outer shell 23 along the second direction, in mm;

[0121] I1 is the thickness dimension of one of the two second wall surfaces 232, in mm;

[0122] I2 is the thickness dimension of the other of the two second wall surfaces 232, in mm.

[0123] By determining the dimension L of the outer shell body 23 along the second direction and the thickness dimensions I1 and I2 of the two second walls 232 of the outer shell body 23 that are arranged opposite each other along the second direction, the dimension V of the receiving cavity 24 along the second direction can be obtained more intuitively by the above structural parameters, which reduces the difficulty of determining the spatial dimension V of the receiving cavity 24 along the second direction.

[0124] The thicknesses I1 and I2 of the two second walls 232 disposed opposite to each other along the second direction of the outer shell 23 can be the same or different. In this embodiment, I1=I2.

[0125] Optionally, as shown in Figures 6 and 7, the second wall surface 232 is provided with a placement groove 233 for accommodating the cover plate module 22 on one side of the open portion of the outer shell body 23. By providing placement grooves 233 on the two second wall surfaces 232 of the outer shell body 23 along the second direction, the cover plate module 22 can be smoothly installed into the outer shell body 23 after assembly. In this embodiment, the depth dimension of the placement groove 233 along the second direction is 0.05mm. Therefore, when the length dimension of the cover plate module 22 along the second direction is set to P, P=L-I1-I2+0.1 is satisfied.

[0126] Optionally, as shown in Figure 9, the outer shell body 23 includes two third walls 234 disposed opposite to each other along a third direction, and the spatial dimension W of the receiving cavity 24 along the third direction is determined according to the following formula: ;

[0127] In the formula:

[0128] T represents the dimension of the outer shell 23 along a third direction, in mm;

[0129] M1 is the thickness dimension of one of the two third wall surfaces 234, in mm;

[0130] M2 is the thickness dimension of the other of the two third wall surfaces 234, in mm.

[0131] By determining the dimension T of the outer shell body 23 along the third direction and the thicknesses M1 and M2 of the two third walls 234 that are arranged opposite each other along the third direction, the dimension W of the receiving cavity 24 along the third direction can be obtained more intuitively by the above structural parameters, which reduces the difficulty of determining the spatial dimension W of the receiving cavity 24 along the third direction.

[0132] The thicknesses M1 and M2 of the two third walls 234 disposed opposite to each other along a third direction of the outer shell 23 can be the same or different. In this embodiment, M1=M2.

[0133] For the outer shell 23, the first wall 231 opposite to the opening needs to support the pole assembly 21, and the second wall 232 needs to have a groove 233 for accommodating the cover plate module 22. Therefore, the thickness relationship between each wall of the outer shell 23 satisfies J>I1=I2>M1=M2.

[0134] Based on the above implementation method, the following implementation method can also be adopted: The effective area when the electrode plate 1 is welded to the pole terminal is determined according to the following formula: ;

[0135] In the formula:

[0136] S represents the effective area when the electrode plate 1 is welded to the terminal block, in mm. 2 ;

[0137] U is the spatial dimension of the receiving cavity 24 along the first direction, in mm;

[0138] V is the spatial dimension of the receiving cavity 24 along the second direction, in mm;

[0139] W represents the spatial dimension of the receiving cavity 24 along the third direction, in mm;

[0140] x is the gap coefficient of pole group 21 along the second direction, in mm;

[0141] y is the gap coefficient of pole group 21 along the first direction, in mm;

[0142] δ is the capacity coefficient of cell 2, in Ah / mm². 3 ;

[0143] A represents the charge / discharge rate of cell 2;

[0144] 7 represents the current coefficient for welding the electrode plate 1 to the terminal block, in Ah / mm. 2 In this embodiment, the calculation methods for parameters U, V, and W, as well as the structure of the battery module, are described above, and the corresponding content also applies to this embodiment.

[0145] Since the spatial dimensions U, V, and W of the receiving cavity 24 along the first direction, the receiving cavity 24 along the second direction, and the receiving cavity 24 along the third direction can be calculated using the structural dimensions of the components in the outer shell 23 and the cover plate module 22, the formula for calculating the effective area S when the electrode plate 1 is welded to the pole terminal can be transformed into:

[0146] ;

[0147] Compared to calculating using the spatial dimensions of the cavity 24 in each direction, this method is less computationally difficult and faster.

[0148] Optionally, the gap coefficient x of the electrode assembly 21 along the second direction satisfies 5mm≤x≤8mm. By limiting the gap coefficient x of the electrode assembly 21 along the second direction to satisfy 5mm≤x≤8mm, it avoids the following: on the one hand, if it is too small, the electrode assembly 21 will have difficulty fitting into the shell, resulting in scratches on the electrode assembly 21; on the other hand, it avoids the following: if it is too large, even after the electrode assembly 21 expands during charging, there will still be a gap between it and the inner wall of the shell body 23, causing the electrode assembly 21 to move and damage the electrode tabs.

[0149] The gap coefficient x of the electrode assembly 21 along the second direction is the gap between the electrode assembly 21 and the shell + the length of the overhang between the separator and the negative electrode + the length of the overhang between the negative electrode and the positive electrode. The gap between the electrode assembly 21 and the shell is the distance between the two sides of the electrode assembly 21 along the second direction and the inner surface of the adjacent second wall surface 232. The length of the overhang between the separator and the negative electrode refers to the distance of the two sides of the separator that extends beyond the two sides of the negative electrode along the second direction. The length of the overhang between the negative electrode and the positive electrode refers to the distance of the two sides of the negative electrode that extends beyond the two sides of the positive electrode along the second direction.

[0150] To verify the effect of the gap coefficient x of the electrode assembly 21 along the second direction on the insertion of the electrode assembly 21 into the housing, as shown in Table 1, three sets of embodiments and two sets of comparative examples are provided for verification.

[0151] Table 1

[0152]

[0153] As shown in the table above, when the gap coefficient x of the electrode assembly 21 along the second direction meets the requirement of 5mm≤x≤8mm, the insertion into the shell is smooth. When the gap coefficient x of the electrode assembly 21 along the second direction is less than 5mm, the gap of the electrode assembly 21 is too small when it is inserted into the shell, making it difficult to insert into the shell, which causes the electrode assembly 21 to be scratched. When the gap coefficient x of the electrode assembly 21 along the second direction is greater than ≤8mm, the electrode assembly 21 moves around, which causes the tab to be pulled.

[0154] Optionally, the gap coefficient y of the electrode assembly 21 along the first direction satisfies 5mm≤y≤10mm. By limiting the gap coefficient y of the electrode assembly 21 along the first direction to satisfy 5mm≤y≤10mm, it avoids being too small, which would not provide enough space for the bending of the electrode tab and cause it to be crushed. On the other hand, it avoids being too large, which would cause a gap between the electrode assembly 21 and the inner wall of the outer shell 23 even after charging and expansion, causing the electrode assembly 21 to move and damage the electrode tab.

[0155] In this embodiment, the gap coefficient y of the electrode group 21 along the first direction is the length of the overhang between the separator and the negative electrode + the length of the overhang between the negative electrode and the positive electrode. The length of the overhang between the separator and the negative electrode refers to the distance of the portion of the separator extending beyond the sides of the negative electrode along the first direction, and the length of the overhang between the negative electrode and the positive electrode refers to the distance of the portion of the negative electrode extending beyond the sides of the positive electrode along the first direction.

[0156] To verify the effect of the gap coefficient y of the electrode assembly 21 along the first direction on the insertion of the electrode assembly 21 into the housing, as shown in Table 2, three sets of embodiments and two sets of comparative examples are provided for verification.

[0157] Table 2

[0158]

[0159] As shown in the table above, when the gap coefficient y of the electrode assembly 21 along the first direction meets the requirement of 5mm≤y≤10mm, the insertion into the shell is smooth. When the gap coefficient y of the electrode assembly 21 along the first direction is less than 5mm, it cannot provide enough space for the bending of the electrode tab, resulting in the electrode tab being crushed. When the gap coefficient y of the electrode assembly 21 along the first direction is greater than 10mm, the electrode assembly 21 moves around, resulting in the electrode tab being pulled.

[0160] Optionally, in the lithium iron phosphate system, the capacity coefficient δ of cell 2 satisfies By limiting the capacity coefficient δ of cell 2 in the lithium iron phosphate system, the capacity coefficient δ is made to satisfy... This ensures that the effective area S obtained from the calculation of the electrode plate 1 and the electrode terminal is highly targeted and accurate.

[0161] Optionally, in the ternary system, the capacity coefficient δ of the single cell 2 satisfies By limiting the capacity coefficient δ of the single cell 2 in the ternary system, the capacity coefficient δ is made to satisfy... This ensures that the effective area S obtained from the calculation of the electrode plate 1 and the electrode terminal is highly targeted and accurate.

[0162] In this embodiment, the capacity coefficient of a single cell 2 is calculated based on its capacity. The capacity of a single cell 2 is defined as C, and the capacity C of a single cell 2 is calculated as: Length of the positive electrode sheet region × Height of the positive electrode sheet region × Areal density of the positive electrode × Active material content × 2 × Specific capacity of the positive electrode × Number of positive electrode layers. The units for the length and height of the positive electrode sheet region are mm, and the unit for areal density is mg / cm³. 2 The unit of capacity is mAh / g, and the active material content is %. Optionally, the length of the positive electrode sheet region = L - I1 - I2 - x, and the height of the positive electrode sheet region = HJay. The assembly ratio is 89%–91%, therefore we can obtain , in the formula Let δ be the value of the single cell 2, and then we can obtain the capacity coefficient δ. The units of each parameter in the formula are converted to mm. 2 Convert to cm 2 mg is converted to g, mAh is converted to Ah, and parameter "2" represents coating on both sides of the foil.

[0163] In the above formula, the positive electrode surface density is 20 mg / cm³. 2 ~25mg / cm 2 The active material content is 95%–98%, the specific capacity of the positive electrode in the lithium iron phosphate system is 135 mAh / g–155 mAh / g, the specific capacity of the positive electrode in the ternary system is 180 mAh / g–210 mAh / g, the thickness of the positive electrode sheet is 155 μm–215 μm, the thickness of the negative electrode sheet is 105 μm–167 μm, and the thickness of the separator is 10 μm–12 μm. Substituting the above data, the capacity coefficient δ of the single cell 2 in the lithium iron phosphate system is obtained, i.e. The capacity coefficient δ of cell 2 in the ternary system is obtained, i.e. .

[0164] Table 3

[0165]

[0166] By limiting the above parameters according to the values ​​in Table 3, the lower limit of the effective area S of the electrode terminal of the single cell 2 and the electrode plate 1 when welding is obtained in different systems under the current size specification. That is, in the ternary system, the effective area S of the electrode plate 1 and the electrode terminal when welding must satisfy S≮23.97mm. 2 In the lithium iron phosphate system, the effective area S of the electrode plate 1 and the terminal block during welding satisfies S ≮ 17.91 mm². 2 .

[0167] To verify the rationality of the effective area S of the electrode plate 1 and the pole terminal obtained by calculating the above parameters during welding, as shown in Table 4, three sets of examples and three sets of comparative examples were selected to verify the calculation results in the ternary system and to observe the temperature of the welding area between the pole terminal and the electrode plate 1 under different welding areas.

[0168] Table 4

[0169]

[0170] As shown in Table 4, in a ternary system, when the effective area S of the electrode 1 and the terminal post during welding is greater than the lower limit of the effective area S of the electrode 1 and the terminal post during welding calculated by the above parameters, the temperature of the solder area is less than 65°C, and the performance is good. When the effective area S of the electrode 1 and the terminal post during welding is less than the lower limit of the effective area S of the electrode 1 and the terminal post during welding calculated by the above parameters, the temperature of the solder area exceeds 65°C, the cell cycle performance decreases, and an external cooling device is required, resulting in high cost.

[0171] In this embodiment, a battery pack is also provided, comprising an electrical connection structure and a plurality of the aforementioned battery modules. The plurality of battery modules are arranged sequentially and connected to each other, and the electrical connection structure is electrically connected to the plurality of battery modules. By applying the aforementioned battery modules, the battery pack can reduce waiting time during the production process as computing speed increases, thereby improving overall production efficiency.

[0172] It should be noted that the above markings: 100, bar-shaped solder mark; 200, circular solder mark; 300, square solder mark; 1, plate; 2, single cell; 21, electrode assembly; 22, cover module; 221, first surface; 222, second surface; 223, cover body; 224, inner insulating component; 23, outer shell body; 231, first wall surface; 232, second wall surface; 233, placement groove; 234, third wall surface; 24, receiving cavity, are only applied in Embodiment A.

[0173] Example B

[0174] To reduce the difficulty of calculation and improve the speed of calculation, this embodiment provides a battery module.

[0175] As shown in Figures 1, 2, and 10 to 15, the battery module includes a battery pack 1 and multiple individual battery cells 2. Each individual battery cell 2 includes an electrode assembly 21, a first cover plate module 22, a second cover plate module 23, and a housing body 24 with openings on both sides. The first cover plate module 22 and the second cover plate module 23 are respectively located at the openings of the housing body 24 to form a receiving cavity 25 for accommodating the electrode assembly 21. Both the first cover plate module 22 and the second cover plate module 23 are provided with terminal posts that are welded to the battery pack 1. The effective area of ​​the battery pack 1 when welded to each terminal post is determined according to the following formula: ;

[0176] In the formula:

[0177] S represents the effective area when the electrode plate 1 is welded to the terminal block, in mm. 2 ;

[0178] U is the spatial dimension of the receiving cavity 25 along the first direction, in mm;

[0179] V is the spatial dimension of the receiving cavity 25 along the second direction, in mm;

[0180] W represents the spatial dimension of the cavity 25 along the third direction, in mm;

[0181] x is the gap coefficient of pole group 21 along the first direction, in mm;

[0182] y is the gap coefficient of pole group 21 along the second direction, in mm;

[0183] δ is the capacity coefficient of cell 2, in Ah / mm². 3 ;

[0184] A represents the charge / discharge rate of cell 2;

[0185] 7 represents the current coefficient for welding the electrode plate 1 to the terminal block, in Ah / mm. 2 .

[0186] Through formula When calculating the lower limit of the effective area of ​​the battery module when the plate 1 is welded to the terminal post, it is only necessary to use the spatial dimensions of the receiving cavity 25, namely the spatial dimension U of the receiving cavity 25 along the first direction, the spatial dimension V of the receiving cavity 25 along the second direction, and the spatial dimension W of the receiving cavity 25 along the third direction, combined with the charge / discharge rate A and the capacity coefficient δ of the single cell 2. There is no need to calculate the capacity of the single cell 2 separately, thereby reducing the parameters that need to be calculated, reducing the difficulty of calculation, improving the calculation speed, and shortening the calculation cycle.

[0187] In this embodiment, since batteries of different sizes have different charge / discharge rates A, when calculating the charge / discharge rate A of a single battery 2, the time Z required for the current single battery 2 to be fully charged is first determined, in minutes; then, the charge / discharge rate A of the current single battery 2 is obtained by calculating according to the formula A=60min / Z.

[0188] Since the material of the electrode plate 1 is aluminum, and the electrode plate 1 is welded to the terminal of the electrode plate outside the single cell 2, the overcurrent coefficient in the calculation formula is determined to be 7 according to the national standard. In addition, as shown in Figure 2, the welding trajectory of the electrode plate 1 and the terminal plate can be freely set to form a strip weld mark 100, a circular weld mark 200 or a square weld mark 300, etc., as long as the effective area after welding meets the calculation requirements.

[0189] Optionally, as shown in Figures 11 to 14, the first cover module 22 includes a first surface 221 facing away from the electrode group 21, a second surface 222 abutting against the electrode group 21, and a third surface 223 abutting against the outer shell body 24. The second cover module 23 includes a fourth surface 231 facing away from the electrode group 21, a fifth surface 232 abutting against the electrode group 21, and a sixth surface 233 abutting against the outer shell body 24. The spatial dimension U of the receiving cavity 25 along the first direction is determined according to the following formula: ;

[0190] In the formula:

[0191] L is the dimension of the outer shell 24 along the first direction, in mm;

[0192] a1 is the distance between the first surface 221 and the second surface 222 along the first direction, in mm;

[0193] b1 is the distance between the first surface 221 and the third surface 223 along the first direction, in mm;

[0194] a2 is the spacing between the fourth surface 231 and the fifth surface 232 along the first direction, in mm;

[0195] b2 is the distance between the fourth surface 231 and the sixth surface 233 along the first direction, in mm.

[0196] By determining the dimension L of the outer shell body 24 along the first direction, the spacing a1 of the first surface 221 and the second surface 222 of the first cover module 22 along the first direction, the spacing b1 of the first surface 221 and the third surface 223 of the first cover module 22 along the first direction, and the spacing a2 of the fourth surface 231 and the fifth surface 232 of the second cover module 23 along the first direction and the spacing b2 of the fourth surface 231 and the sixth surface 233 of the fourth cover module 23 along the first direction, the spatial dimension U of the receiving cavity 25 along the first direction can be obtained more intuitively by the above structural parameters, reducing the difficulty of determining the spatial dimension U of the receiving cavity 25 along the first direction.

[0197] In this embodiment, the first cover plate module 22 includes a first cover plate body 224, and the first cover plate body 224 includes a first sealing portion 2241 and a first insertion portion 2242. The first sealing portion 2241 protrudes from the surface of the electrode group 21 in the direction close to the electrode group 21 to form the first insertion portion 2242. The first insertion portion 2242 is inserted into the inside of the outer shell body 24. The first sealing portion 2241 is used to close the opening of the outer shell body 24. The first surface 221 is the surface of the first sealing portion 2241 that is away from the electrode group 21. The surface of the first sealing portion 2241 that abuts against the outer shell body 24 is the third surface 223. The first cover plate module 22 also has a first lower insulating member 225 located inside the outer shell body 24 and used to abut against the electrode group 21. The surface of the first lower insulating member 225 that abuts against the electrode group 21 is the second surface 222.

[0198] In this embodiment, the second cover plate module 23 includes a second cover plate body 234, and the second cover plate body 234 includes a second sealing portion 2341 and a second insertion portion 2342. The second sealing portion 2341 protrudes from the surface of the electrode group 21 in the direction close to the electrode group 21 to form the second insertion portion 2342. The second insertion portion 2342 is inserted into the inside of the outer shell body 24. The second sealing portion 2341 is used to close the opening of the outer shell body 24. The fourth surface 231 is the surface of the second sealing portion 2341 that is away from the electrode group 21. The surface of the second sealing portion 2341 that abuts against the outer shell body 24 is the sixth surface 233. The second cover plate module 23 also has a second lower insulating member 235 located inside the outer shell body 24 and used to abut against the electrode group 21. The surface of the second lower insulating member 235 that abuts against the electrode group 21 is the fifth surface 232.

[0199] Optionally, as shown in Figures 14 and 15, the outer casing 24 includes a first wall surface 241 and a fourth wall surface 244 disposed opposite to each other along the second direction, and the spatial dimension V of the receiving cavity 25 along the second direction is determined according to the following formula: ;

[0200] In the formula:

[0201] H is the dimension of the outer shell 24 along the second direction, in mm;

[0202] t1 is the thickness of the first wall surface 241, in mm;

[0203] t4 is the thickness dimension of the fourth wall surface 244, in mm.

[0204] By determining the dimension H of the outer shell 24 along the second direction, the thickness t1 of the first wall 241 of the outer shell 24, and the thickness t4 of the fourth wall 244 of the outer shell 24, the dimension V of the receiving cavity 25 along the second direction can be obtained more intuitively through the above structural parameters, reducing the difficulty of determining the spatial dimension V of the receiving cavity 25 along the second direction.

[0205] Optionally, as shown in Figures 14 and 15, the outer casing 24 includes a second wall surface 242 and a third wall surface 243 disposed opposite to each other along a third direction, and the spatial dimension W of the receiving cavity 25 along the third direction is determined according to the following formula: ;

[0206] In the formula:

[0207] T represents the dimension of the outer shell 24 along a third direction, in mm;

[0208] t2 is the thickness of the second wall surface 242, in mm;

[0209] t3 is the thickness of the third wall surface 243, in mm.

[0210] By determining the dimension T of the outer shell 24 along the third direction, the wall thickness t2 of the second wall 242 of the outer shell 24, and the wall thickness t3 of the third wall 243 of the outer shell 24, the dimension W of the receiving cavity 25 along the third direction can be calculated more intuitively using the above structural parameters, reducing the difficulty of determining the spatial dimension W of the receiving cavity 25 along the third direction.

[0211] The thicknesses of the first wall surface 241, the second wall surface 242, the third wall surface 243, and the fourth wall surface 244 constituting the outer shell body 24 can be the same or different. The forming of the outer shell body 24 generally includes two processes: aluminum plate bending and welding, and aluminum rod extrusion. The outer shell body 24 with equal wall thickness generally adopts the aluminum plate bending and laser welding process, while the outer shell body 24 with unequal wall thickness generally adopts the extrusion process. In this embodiment, the outer shell body 24 with equal wall thickness by bending and laser welding is preferred, that is, t1=t2=t3=t4.

[0212] Since the spatial dimensions U, V, and W of the receiving cavity 25 along the first direction, the second direction, and the third direction can be calculated using the structural dimensions of the components in the outer shell 24, the first cover module 22, and the second cover module 23, the formula for calculating the effective area S when the electrode plate 1 is welded to the pole terminal can be transformed into: Compared to calculating using the spatial dimensions of the cavity 25 in each direction, this method is less computationally difficult and faster.

[0213] Optionally, the gap coefficient x of the electrode assembly 21 along the first direction satisfies 8mm≤x≤12mm. By limiting the gap coefficient x of the electrode assembly 21 along the first direction to satisfy 8mm≤x≤12mm, it avoids being too small, which would not provide enough space for the bending of the electrode tab and cause it to be crushed. On the other hand, it avoids being too large, which would cause a gap between the electrode assembly 21 and the inner wall of the outer shell 24 even after charging and expansion, causing the electrode assembly 21 to move and damage the electrode tab.

[0214] In this embodiment, the gap coefficient x of the electrode group 21 along the first direction is the length of the overhang between the separator and the negative electrode + the length of the overhang between the negative electrode and the positive electrode. The length of the overhang between the separator and the negative electrode refers to the distance of the portion of the separator extending beyond the sides of the negative electrode along the first direction, and the length of the overhang between the negative electrode and the positive electrode refers to the distance of the portion of the negative electrode extending beyond the sides of the positive electrode along the first direction.

[0215] To verify the effect of the gap coefficient x of the electrode assembly 21 along the first direction on the insertion of the electrode assembly 21 into the housing, as shown in Table 5, three sets of embodiments and two sets of comparative examples are provided for verification.

[0216] Table 5

[0217]

[0218] As shown in the table above, when the gap coefficient x of the electrode assembly 21 along the first direction meets the requirement of 8mm≤x≤12mm, the insertion into the shell is smooth. When the gap coefficient x of the electrode assembly 21 along the first direction is less than the minimum value of the range of 8mm≤x≤12mm, it cannot provide enough space for the bending of the electrode tab, resulting in the electrode tab being crushed. When the gap coefficient x of the electrode assembly 21 along the first direction is greater than the maximum value of the range of 8mm≤x≤12mm, the electrode assembly 21 moves around, resulting in the electrode tab being pulled.

[0219] Optionally, the gap coefficient y of the electrode assembly 21 along the second direction satisfies 6mm≤y≤9mm. By limiting the gap coefficient y of the electrode assembly 21 along the second direction to satisfy 6mm≤y≤9mm, it avoids the following: on the one hand, if it is too small, it will be difficult for the electrode assembly 21 to fit into the shell, resulting in scratches on the electrode assembly 21; on the other hand, it avoids the following: if it is too large, even after the electrode assembly 21 expands during charging, there will still be a gap between it and the inner wall of the shell body 24, causing the electrode assembly 21 to move and damage the electrode tabs.

[0220] In this embodiment, the gap coefficient y of the electrode assembly 21 along the second direction is the gap between the electrode assembly 21 and the housing + the height of the separator and the negative electrode overhang + the height of the negative electrode and the positive electrode overhang. The gap between the electrode assembly 21 and the housing is the distance between the two sides of the electrode assembly 21 along the second direction and the inner surfaces of the opposing first wall surface 241 and fourth wall surface 244. The height of the separator and the negative electrode overhang refers to the distance of the two sides of the separator extending beyond the two sides of the negative electrode along the second direction. The height of the negative electrode and the positive electrode overhang refers to the distance of the two sides of the negative electrode extending beyond the two sides of the positive electrode along the second direction.

[0221] To verify the effect of the gap coefficient y of the electrode assembly 21 along the second direction on the insertion of the electrode assembly 21 into the housing, as shown in Table 6, three sets of embodiments and two sets of comparative examples are provided for verification.

[0222] Table 6

[0223]

[0224] As shown in the table above, when the gap coefficient y of the electrode assembly 21 along the second direction meets the requirement of 6mm≤y≤9mm, it is smoothly inserted into the shell. When the gap coefficient y of the electrode assembly 21 along the second direction is less than the minimum value of the range of 6mm≤y≤9mm, the gap of the electrode assembly 21 is too small when it is inserted into the shell, which causes the electrode assembly 21 to be scratched. When the gap coefficient y of the electrode assembly 21 along the second direction is greater than the maximum value of the range of 6mm≤y≤9mm, the electrode assembly 21 moves around, which causes the tab to be pulled.

[0225] Optionally, in the lithium iron phosphate system, the capacity coefficient δ of cell 2 satisfies By limiting the capacity coefficient δ of cell 2 in the lithium iron phosphate system, it is made to meet the requirements. This ensures that the effective area S obtained from the calculation of the electrode plate 1 and the electrode terminal is highly targeted and accurate.

[0226] Optionally, in the ternary system, the capacity coefficient δ of the single cell 2 satisfies By limiting the capacity coefficient δ of cell 2 in the ternary system, it is made to meet the requirements. This ensures that the effective area S obtained from the calculation of the electrode plate 1 and the electrode terminal is highly targeted and accurate.

[0227] In this embodiment, the capacity coefficient of a single cell 2 is derived from the capacity calculation of a single cell 2. The capacity of a single cell 2 is defined as C, and the capacity C of a single cell 2 is calculated as: Length of the positive electrode sheet region × Height of the positive electrode sheet region × Areal density of the positive electrode × Active material content × 2 × Positive electrode specific capacity × Number of positive electrode layers. The units for the length and height of the positive electrode sheet region are mm, and the unit for areal density is mg / cm³. 2 The unit of capacity is mAh / g, and the active material content is %. Optionally, the length of the positive electrode sheet region = L + b1 + b2 - a1 - a2 - x, and the height of the positive electrode sheet region = H - t1 - t4 - y. The assembly ratio is 89%–91%, therefore we can obtain , in the formula Let δ be the value of the single cell 2, and then we can obtain the capacity coefficient δ. The units of the parameters in the formula are converted to mm. 2 Convert to cm 2 mg is converted to g, mAh is converted to Ah, and parameter "2" represents coating on both sides of the foil.

[0228] In the above formula, the positive electrode surface density is 20 mg / cm³. 2 ~25mg / cm 2 The active material content is 95%–98%, the specific capacity of the positive electrode in the lithium iron phosphate system is 135 mAh / g–155 mAh / g, the specific capacity of the positive electrode in the ternary system is 180 mAh / g–210 mAh / g, the thickness of the positive electrode sheet is 155 μm–215 μm, the thickness of the negative electrode sheet is 105 μm–167 μm, and the thickness of the separator is 10 μm–12 μm. Substituting the above data, the capacity coefficient δ of the single cell 2 in the lithium iron phosphate system is obtained, i.e. The capacity coefficient δ of cell 2 in the ternary system is obtained, i.e. .

[0229] Optionally, the distance b1 between the first surface 221 and the third surface 223 along the first direction satisfies b1≥0.5mm, for example 0.75mm; by limiting the distance b1 between the first surface 221 and the third surface 223 along the first direction, the size is avoided from being too small, which would result in low structural strength and easy deformation.

[0230] The distance b2 between the fourth surface 231 and the sixth surface 233 along the first direction satisfies b2≥0.5mm, preferably 0.75mm. By limiting the distance b2 between the fourth surface 231 and the sixth surface 233 along the first direction, it is avoided that the size is too small, which would result in low structural strength and easy deformation.

[0231] Table 7

[0232]

[0233] The above parameters are limited according to the values ​​in Table 7 to obtain the lower limit of the effective area S of the electrode terminal of the single cell 2 and the electrode plate 1 when welding in different systems under the current size specification. That is, in the ternary system, the effective area S of the electrode plate 1 and the electrode terminal when welding is S≮23.4mm2, and in the lithium iron phosphate system, the effective area S of the electrode plate 1 and the electrode terminal when welding is S≮17.4mm2.

[0234] To verify the rationality of the effective area S of the electrode plate 1 and the pole terminal obtained by calculating the above parameters during welding, as shown in Table 8, three sets of examples and three sets of comparative examples were selected to verify the calculation results in the ternary system and to observe the temperature of the welding area between the pole terminal and the electrode plate 1 under different welding areas.

[0235] Table 8

[0236]

[0237] As shown in Table 8, in a ternary system, when the effective area S of the electrode 1 and the terminal post during welding is greater than the lower limit of the effective area S of the electrode 1 and the terminal post during welding, calculated using the above parameters, the temperature of the solder area is less than 65°C, and the performance is good. When the effective area S of the electrode 1 and the terminal post during welding is less than the lower limit of the effective area S of the electrode 1 and the terminal post during welding, calculated using the above parameters, the temperature of the solder area exceeds 65°C, the cell cycle performance decreases, and an external cooling device is required, resulting in high cost.

[0238] In this embodiment, a battery pack is also provided. The battery pack includes an electrical connection structure and multiple battery modules as described above. The multiple battery modules are arranged sequentially and connected to each other, and the electrical connection structure is electrically connected to the multiple battery modules. By applying the battery modules described above, the battery pack can reduce waiting time during the battery pack production process as computing speed increases, thereby improving overall production efficiency.

[0239] It should be noted that the above markings: 100, bar weld mark; 200, circular weld mark; 300, square weld mark; 1, plate; 2, single cell; 21, electrode group; 22, first cover module; 221, first surface; 222, second surface; 223, third surface; 224, first cover body; 2241, first sealing part; 2242, first plug-in part; 225, first lower insulating member; 23, second cover module; 231, fourth surface; 232, fifth surface; 233, sixth surface; 234, second cover body; 2341, second sealing part; 2342, second plug-in part; 235, second lower insulating member; 24, outer shell body; 241, first wall surface; 242, second wall surface; 243, third wall surface; 244, fourth wall surface; 25, receiving cavity, are only applied in Embodiment B.

Claims

1. A battery module, comprising a battery plate and multiple individual cells, each individual cell comprising an electrode assembly, a cover plate module, and a housing body with an opening on one side, the cover plate module being disposed at the opening of the housing body, the cover plate module and the housing body forming a receiving cavity for accommodating the electrode assembly, the cover plate module being provided with terminal posts welded to the battery plate, the effective area of ​​the battery plate when welded to the terminal post being determined according to the following formula: ; In the formula: S is the effective area of the pad when welded to the pole terminal, in mm 2 ; U is the spatial dimension of the receiving cavity along the first direction, in mm; V is the spatial dimension of the receiving cavity along the second direction, in mm; W represents the spatial dimension of the receiving cavity along a third direction, in mm; x is the gap coefficient of the pole group along the second direction, in mm; y is the gap coefficient of the pole group along the first direction, in mm; δ is the capacity coefficient of the monobloc battery, in Ah / mm 3 ; A represents the charge / discharge rate of the individual battery cell; 7 represents the current coefficient for welding the electrode plate to the terminal block, in Ah / mm. 2 .

2. The battery module according to claim 1, wherein, The cover module includes a first surface facing away from the electrode assembly and a second surface abutting against the electrode assembly. The outer shell body includes a first wall surface opposite to the opening. The spatial dimension U of the receiving cavity along the first direction is determined according to the following formula: ; In the formula: H is the dimension of the outer shell body along the first direction, in mm; 'a' represents the distance between the first surface and the second surface along the first direction, in mm. J represents the thickness of the first wall surface, in mm.

3. The battery module according to claim 1, wherein, The outer shell body includes two second walls disposed opposite each other along the second direction, and the spatial dimension V of the receiving cavity along the second direction is determined according to the following formula: ; In the formula: L is the dimension of the outer shell body along the second direction, in mm; I1 is the thickness dimension of one of the two second wall surfaces, in mm; I2 is the thickness dimension of the other of the two second wall surfaces, in mm.

4. The battery module according to claim 1, wherein, The outer shell body includes two third walls disposed opposite each other along the third direction, and the spatial dimension W of the receiving cavity along the third direction is determined according to the following formula: ; In the formula: T represents the dimension of the outer shell body along the third direction, in mm; M1 is the thickness dimension of one of the two third wall surfaces, in mm; M2 is the thickness dimension of the other of the two third wall surfaces, in mm.

5. The battery module according to claim 1, wherein, The gap coefficient x of the electrode group along the second direction satisfies 5mm≤x≤8mm.

6. The battery module of claim 1, wherein, The gap coefficient y of the electrode group along the first direction satisfies 5mm≤y≤10mm.

7. The battery module according to claim 1, wherein, In the lithium iron phosphate system, the capacity coefficient δ of the single cell satisfies... .

8. The battery module according to claim 1, wherein, In a ternary system, the capacity coefficient δ of the single cell satisfies .

9. The battery module according to claim 3, wherein, The second wall surface has a placement groove on one side of the opening of the outer shell body, which is configured to accommodate the cover plate module.

10. A battery module, the battery module comprising a battery pack and multiple individual cells, each individual cell comprising an electrode assembly, a first cover plate module, a second cover plate module, and a housing body with openings on both sides, the first cover plate module and the second cover plate module being respectively disposed at the openings of the housing body, the first cover plate module and the second cover plate module forming a receiving cavity with the housing body to accommodate the electrode assembly, and both the first cover plate module and the second cover plate module being provided with electrode terminals welded to the battery pack, the effective area of ​​the battery pack when welded to each electrode terminal being determined according to the following formula: ； In the formula: S represents the effective area when the electrode plate is welded to the terminal block, in mm. 2 ; U is the spatial dimension of the receiving cavity along the first direction, in mm; V is the spatial dimension of the receiving cavity along the second direction, in mm; W represents the spatial dimension of the receiving cavity along a third direction, in mm; x is the gap coefficient of the pole group along the first direction, in mm; y is the gap coefficient of the pole group along the second direction, in mm; δ represents the capacity coefficient of the individual battery cell, with units of Ah / mm². 3 ; A represents the charge / discharge rate of the individual battery cell; 7 represents the current coefficient for welding the electrode plate to the terminal block, in Ah / mm. 2 .

11. The battery module according to claim 10, wherein, The first cover module includes a first surface facing away from the electrode group, a second surface abutting against the electrode group, and a third surface abutting against the outer shell body. The second cover module includes a fourth surface facing away from the electrode group, a fifth surface abutting against the electrode group, and a sixth surface abutting against the outer shell body. The spatial dimension U of the receiving cavity along the first direction is determined according to the following formula: ; In the formula: L is the dimension of the outer shell body along the first direction, in mm; a1 is the distance between the first surface and the second surface along the first direction, in mm; b1 is the distance between the first surface and the third surface along the first direction, in mm; a2 is the distance between the fourth surface and the fifth surface along the first direction, in mm; b2 is the distance between the fourth surface and the sixth surface along the first direction, in mm.

12. The battery module according to claim 10, wherein, The outer shell body includes a first wall and a fourth wall disposed opposite to each other along the second direction, and the spatial dimension V of the receiving cavity along the second direction is determined according to the following formula: ; In the formula: H is the dimension of the outer shell body along the second direction, in mm; t1 is the thickness of the first wall surface, in mm; t4 is the thickness of the fourth wall surface, in mm.

13. The battery module according to claim 10, wherein, The outer shell body includes a second wall and a third wall disposed opposite to each other along the third direction, and the spatial dimension W of the receiving cavity along the third direction is determined according to the following formula: ; In the formula: T represents the dimension of the outer shell body along the third direction, in mm; t2 is the thickness of the second wall surface, in mm; t3 is the thickness of the third wall surface, in mm.

14. The battery module according to claim 10, wherein, The gap coefficient x of the electrode group along the first direction satisfies 8mm≤x≤12mm.

15. The battery module according to claim 10, wherein, The gap coefficient y of the pole group along the second direction satisfies 6mm≤y≤9mm.

16. The battery module according to claim 10, wherein, In the lithium iron phosphate system, the capacity coefficient δ of the single cell satisfies... .

17. The battery module of claim 10, wherein, In a ternary system, the capacity coefficient δ of the single cell satisfies .

18. The battery module according to claim 11, wherein, The distance b1 between the first surface and the third surface along the first direction satisfies b1≥0.5mm; And / or, the distance b2 between the fourth surface and the sixth surface along the first direction satisfies b2≥0.5mm.

19. A battery pack, the battery pack comprising an electrical connection structure and a plurality of battery modules as described in any one of claims 1-9 or as described in any one of claims 11-19, wherein the plurality of battery modules are arranged sequentially and connected to each other, and the electrical connection structure is electrically connected to the plurality of battery modules.

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