Battery cell and battery pack

Abstract

The application relates to the technical field of batteries, and discloses a battery cell and a battery pack. The battery cell comprises a shell structure, two shells adjacent in a Y direction, a protruding part and a recessed part on one side of the shell in the Y direction, the protruding part on each shell being arranged in the recessed part on the other shell, and a mounting groove on one side of each protruding part facing the other protruding part in an X direction; a pole group structure comprising two pole group monomers, the two pole group monomers being arranged in the two shells; and a first rotating shaft arranged between the two protruding parts, one end of the first rotating shaft being rotatably inserted into the mounting groove on one protruding part, the other end of the first rotating shaft being rotatably inserted into the mounting groove on the other protruding part, and the two shells being relatively rotatable around the axis of the first rotating shaft. The shell structure adopts a rotating structure design, the battery cell can flexibly adjust the angle of the battery cell according to the shape of the installation space, adapt to different scene requirements such as irregularly arranged spaces, and improve the space utilization rate.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to battery cells and battery packs. Background Technology

[0002] Lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage. Lithium-ion cells are the basic building blocks of battery packs, and their structural design is crucial to the performance of the entire battery pack. Utilizing the space on the vehicle chassis effectively improves the overall energy density and performance of the vehicle. However, the irregular shapes and protrusions on the vehicle chassis make traditional square battery cells less flexible and difficult to adapt to these irregular spaces or fully fit the chassis shape. This results in low space utilization on the vehicle chassis, hindering the improvement of the overall energy density. Summary of the Invention

[0003] This invention provides a battery cell and battery pack to solve the problem of poor flexibility of battery cells and difficulty in adapting to irregularly shaped spaces.

[0004] In a first aspect, the present invention provides a battery cell, comprising: a housing structure including two housings arranged adjacent to each other along the Y direction, each housing having a protrusion and a recess on one side along the Y direction, the protrusion on each housing being disposed in the recess on the other housing, and each protrusion having a mounting groove on one side along the X direction toward the other protrusion; an electrode assembly structure including two electrode assembly units, the two electrode assembly units being disposed separately in the two housings; and a first rotating shaft disposed between the two protrusions, one end of the first rotating shaft being rotatably inserted into the mounting groove on one of the protrusions, and the other end being rotatably inserted into the mounting groove on the other protrusion, the two housings being rotatable relative to each other about the axis of the first rotating shaft.

[0005] Beneficial effects: By setting the housing structure to consist of two housings, and the electrode assembly structure to consist of two electrode units located in the two housings, with the protrusion on one housing located in the recess on the other housing, the overall housing structure is compact. The protrusions of the two housings are rotatably connected by a first rotating shaft, allowing the two housings to rotate relative to each other around the axis of the first rotating shaft. The housing structure adopts a rotating structure design, which allows the cells to flexibly adjust their angle according to the shape of the installation space, adapting to different scenario requirements such as irregular installation spaces of the car chassis, which is conducive to improving space utilization and thus effectively improving the overall energy density of the battery pack. This solves the problems of poor flexibility and inability to adapt to irregular installation spaces of traditional square cells.

[0006] In one optional embodiment, the two protrusions are spaced apart along the X direction, and the distance between them is K, wherein 2 mm ≤ K ≤ 8 mm; And / or, the dimension of the housing along the Z direction is B, the mounting groove is a cylindrical groove, and the diameter of the mounting groove is D, wherein 7 mm ≤ BD ≤ 20 mm; And / or, the protrusion has a dimension of W1 along the Y direction, the mounting groove has a first center line parallel to the X direction, and the distance between the first center line and the edge of the protrusion along the Y direction is W2, where W2 / W1=0.5; And / or, in the YZ plane, the wall thickness of the shell is T, where 0.3 mm ≤ T ≤ 0.8 mm; And / or, the depth of the mounting groove along the X direction is H2, wherein 20 mm ≤ H2 ≤ 80 mm.

[0007] Beneficial effects: By limiting K to a value within the range of 2 mm to 8 mm, interference between the two protrusions can be avoided, ensuring the flexibility of relative rotation between the two housings. At the same time, space can be avoided, improving the overall space utilization of the battery cell and ensuring the energy density of the battery cell. And / or, by limiting BD to a value in the range of 7 mm to 20 mm, it is possible to ensure that the protrusion has sufficient structural strength, reduce the difficulty of processing and forming the shell, and avoid increasing costs due to excessive diameter of the first rotating shaft. At the same time, it is possible to ensure that the diameter of the first rotating shaft meets the strength requirements of the rotating connection, avoid jamming and damage during rotation, and ensure the reliability and economy of the cell structure. And / or, by limiting W2 to half of W1, the mounting groove is located in the middle of the protrusion along the Z direction, which is beneficial for the rotational fit between the two housings; And / or, limiting T to a value within the range of 0.3 mm to 0.8 mm can simultaneously take into account the structural strength of the casing and the energy density requirements of the battery cell; And / or, limiting H2 to a value within the range of 20 mm to 80 mm can ensure the stability of the fit between the first rotating shaft and the mounting slot, prevent the first rotating shaft from falling off during rotation, ensure the reliability of the cell structure, and prevent the mounting slot from occupying too much internal space of the cell, ensuring the arrangement space of the electrode group cells, which is conducive to improving the capacity of the cell.

[0008] In one optional embodiment, the housing further includes a housing body, the protrusion is connected to one side of the housing body along the Y direction, the protrusion is configured as an arc-shaped surface on the side of the housing body away from the housing body along the Y direction, the recess is disposed adjacent to the protrusion along the X direction, and the side of the housing body facing the recess along the Y direction is configured as a first plane.

[0009] Beneficial effects: The arc-shaped surface on one shell corresponds to the first plane on the other shell. The arc-shaped surface can avoid interference with the other shell during rotation, ensuring the smooth relative rotation process between the two shells. At the same time, the other side opposite the arc-shaped surface is a planar structure, which can simplify the processing and improve the production efficiency of the shell.

[0010] In one optional embodiment, the housing further includes a first extension and a second extension, which are respectively disposed at both ends of the housing body along the X direction. The first extension and the second extension each form a receiving space communicating with the inner cavity of the housing body. The electrode assembly includes an electrode assembly body and a first boss and a second boss. The electrode assembly body is disposed inside the housing body. The first boss is disposed in the receiving space formed by the first extension, and the second boss is disposed in the receiving space formed by the second extension.

[0011] Beneficial effects: By setting the first extension and the second extension at both ends of the shell, the total internal space of the shell is increased. At the same time, the shape of the electrode unit is adapted to the shape of the shell. The electrode unit has an electrode body located inside the shell body, and a first boss and a second boss located in the first extension and the second extension, respectively. This allows the electrode unit to make full use of the internal space of the shell, effectively increasing the volume of the electrode unit, thereby improving the overall capacity of the cell and meeting the design requirements of high capacity cells.

[0012] In one optional embodiment, the dimensions of the first extension and the second extension along the X direction are both H1, wherein 10 mm ≤ H1 ≤ 70 mm; And / or, the first extension is connected to one end of the shell body along the X direction near the recess, the first extension has a dimension L1 along the Y direction, and the shell body has a dimension A1 along the Y direction, wherein 0.25≤L1 / A1≤0.5; And / or, the dimension of the shell body along the Y direction is A1, and the total dimension of the shell body and the protrusion along the Y direction is A2, wherein 24 mm ≤ A2 - A1 ≤ 80 mm; And / or, the second extension is connected to one end of the shell body along the X direction near the protrusion, the second extension has a dimension of L2 along the Y direction, and the total dimension of the shell body and the first protrusion along the Y direction is A2, wherein 0.2≤L2 / A2≤0.45; And / or, along the X direction, the end of the protrusion away from the recess is flush with the end of the shell body away from the recess.

[0013] Beneficial effects: Limiting H1 to a value within the range of 10 mm to 70 mm can effectively improve the cell capacity, ensure the structural strength of the casing, and reduce the processing difficulty and production cost of the casing. And / or, limiting L1 / A1 to a value between 0.25 and 0.5 can effectively increase the cell capacity while ensuring the cell's overcurrent capability and meeting the overcurrent requirements for fast charging. And / or, limiting A2-A1 to a value within the range of 24 mm to 80 mm can ensure that the protrusion has sufficient size to provide ample space for the first rotating shaft, ensuring the structural strength of the first rotating shaft, while also ensuring the increase in cell capacity, reducing the difficulty of stamping the housing, ensuring the machining accuracy of the housing, avoiding jamming or damage when the two housings rotate relative to each other after assembly, and improving the reliability of the cell structure; And / or, limiting L2 / A2 to a value between 0.2 and 0.45 can effectively increase the cell capacity and ensure that the terminal structure has sufficient space to meet the overcurrent requirements of fast charging cells; And / or, improve the flatness of the housing ends, facilitate the processing of the housing structure, and facilitate the installation of the electrode assembly units into the housing.

[0014] In one optional embodiment, the electrode assembly unit further includes a third boss, which is connected to one side of the electrode assembly body along the Y direction and is disposed in the inner cavity of the protrusion; the third boss includes a first step portion and a second step portion, the first step portion is connected between the electrode assembly body and the second step portion, the dimension of the second step portion along the X direction is smaller than the dimension of the first step portion along the X direction, a clearance space is formed between the first step portion and the second step portion, and the mounting groove is located in the clearance space.

[0015] Beneficial effects: The electrode assembly can avoid the mounting slots on the housing by avoiding the clearance space, thus preventing structural interference between the electrode assembly and the mounting slots. This ensures that the electrode assembly can be smoothly installed into the inner cavity of the housing. At the same time, the internal space of the protrusion can be fully utilized to arrange the electrode assembly, further increasing the capacity of the cell.

[0016] In one optional implementation, the clearance space has a dimension of W along the X direction, where 20 mm ≤ W ≤ 80 mm; And / or, along the Y direction, the size of the pole group body is a1, the total size of the pole group body and the third boss is a2, and the size of the second step is F, wherein 0.7≤F / (a2-a1)≤0.9, and / or, 25 mm≤a2-a1≤82 mm; And / or, the dimension of the electrode assembly unit along the Z direction is b, where 20 mm ≤ b ≤ 100 mm; And / or, the dimension of the electrode assembly unit along the X direction is e, where 400 mm ≤ e ≤ 980 mm.

[0017] Beneficial effects: Limiting W to a value within the range of 20 mm to 80 mm can ensure that the clearance space can effectively avoid the mounting slot, avoid structural interference, and ensure smooth assembly of the electrode unit and the housing. It can also make full use of the internal space of the protrusion to arrange the electrode unit, ensure the overall capacity of the cell, and meet the high-capacity design requirements. And / or, limiting F / (a2-a1) to a value in the range of 0.7 to 0.9 can provide sufficient space for the mounting slot and the first rotating shaft, ensure the structural strength of the first rotating shaft, and ensure the structural strength of the third boss, thereby improving the structural reliability of the electrode group and the overall battery cell and extending the battery cell's service life. And / or, limiting a2-a1 to values ​​within the range of 25 mm to 82 mm can ensure that the third boss has sufficient size to provide ample space for the mounting slot and the first rotating shaft, ensuring the structural strength of the first rotating shaft, while also reducing the difficulty of stamping the housing, ensuring the housing processing accuracy, avoiding jamming and damage when the two housings rotate relative to each other, and further improving the reliability of the cell structure. And / or, limiting b to a value within the range of 20 mm to 100 mm can ensure that the cell meets the design requirements for large capacity, reduce the processing difficulty, ensure heat dissipation of the individual electrode group, and extend the cycle life of the cell. And / or, limiting e to a value within the range of 400 mm to 980 mm can ensure that the cell meets the design requirements for large capacity, while also ensuring the structural stability of the individual electrode assembly and improving the cell production qualification rate.

[0018] In one optional embodiment, the dimensions of the first boss and the second boss along the X direction are both H, wherein 10 mm ≤ H ≤ 70 mm; And / or, along the Y direction, the dimension of the first boss edge is L4, and the dimension of the pole group body is a1, wherein 0.2≤L4 / a1≤0.5; And / or, along the Y direction, the third protrusion has a first side away from the pole group body, the distance from the second protrusion to the first side is L3, and the total dimension of the pole group body and the third protrusion is a2, wherein 0.36≤L3 / a2≤0.6.

[0019] Beneficial effects: Limiting H to a value within the range of 10 mm to 70 mm can not only increase the overall capacity of the battery cell and meet the requirements of high capacity design, but also ensure the structural strength of the first extension and the second extension, and control the processing difficulty and production cost. And / or, limiting L4 / a1 to a value between 0.2 and 0.5 can effectively increase the cell capacity while ensuring sufficient space for the tabs, thus ensuring the overall overcurrent capacity of the cell and meeting the requirements of fast charging cells. And / or, limiting L3 / a2 to a value within the range of 0.36 to 0.6 can ensure the overcurrent capacity of the battery cell, ensure that the first rotating shaft has sufficient space and structural strength, avoid excessive difficulty in the processing of the casing, ensure the processing accuracy of the casing, avoid jamming and damage when the two casings rotate relative to each other, and further improve the overall reliability of the battery cell structure.

[0020] In one optional embodiment, the second boss has two sides disposed opposite to each other along the Y direction, and the dihedral angle between the two sides is N, wherein 20°≤N≤60°; And / or, along the Y direction, the first boss and the second boss are both located in the middle of the electrode assembly body, and the electrode assembly unit is provided with electrode tabs on both sides of the first boss along the Y direction and on both sides of the second boss along the Y direction.

[0021] Beneficial effects: Limiting N to a value within the range of 20° to 60° can ensure the effective volume of the second boss, effectively increase the cell capacity, and reduce assembly difficulty by utilizing the inclined side, thereby improving the cell assembly efficiency and pass rate. And / or, by providing tabs at the ends of the electrode assembly cells where the first and second protrusions are not provided, the electrode assembly cells can have multiple tabs, which can enhance the overcurrent capacity, facilitate heat dissipation of the tabs, avoid excessive temperature during fast charging, and improve the safety of the battery cell.

[0022] Secondly, the present invention also provides a battery pack, comprising the aforementioned battery cell. Since the battery pack includes the battery cell and has the same effects as the battery cell, it will not be described further here. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1This is a schematic diagram of the structure of a battery cell according to an embodiment of the present invention; Figure 2 for Figure 1 The bottom view of the battery cell shown; Figure 3 for Figure 2 A cross-sectional view along the CC direction; Figure 4 for Figure 1 The front view of the battery cell shown; Figure 5 for Figure 4 Cross-sectional view along the GG direction; Figure 6 This is a schematic diagram of a shell structure according to an embodiment of the present invention; Figure 7 for Figure 6 The exploded view of the shell structure shown; Figure 8 for Figure 6 The front view of the shell structure shown; Figure 9 for Figure 8 A cross-sectional view along the JJ direction; Figure 10 for Figure 9 A magnified view of part M in the diagram; Figure 11 This is a schematic diagram of the structure of a shell according to an embodiment of the present invention; Figure 12 for Figure 11 The cross-sectional view of the shell shown; Figure 13 for Figure 11 The side view of the casing shown; Figure 14 This is a schematic diagram of a pole group structure according to an embodiment of the present invention; Figure 15 This is a schematic diagram of the structure of a polar group monomer according to an embodiment of the present invention; Figure 16 for Figure 15 Side view of the electrode assembly unit shown; Figure 17 This is a top view of a single electrode assembly according to an embodiment of the present invention; Figure 18 for Figure 17 The front view of the electrode assembly unit shown; Figure 19 This is a schematic diagram of the structure of a cover plate assembly according to an embodiment of the present invention; Figure 20 for Figure 19 Top view of the cover plate assembly shown; Figure 21 for Figure 20A cross-sectional view along the PP direction.

[0025] Explanation of reference numerals in the attached figures: 1. Shell structure; 11. Shell; 101. First opening end; 102. Second opening end; 110. Shell body; 111. Protrusion; 112. Recess; 113. Mounting groove; 1131. First centerline; 114. Arc-shaped surface; 115. First plane; 116. First extension; 117. Second extension; 2. Pole assembly structure; 21. Pole assembly unit; 210. Clearance space; 211. Pole assembly body; 212. Third boss; 2121. First step; 2122. Second step; 2123. First side; 213. First boss; 214. Second boss; 2141. Side; 215. Electrode; 3. First pivot; 4. First cover plate; 41. First receiving cavity; 5. Second cover plate; 51. Second receiving cavity; 6. Second pivot; 7. Connector; 8. Electrode structure; 81. Electrode; 82. Riveting block. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage, leading to increasingly stringent requirements for their performance and safety. The battery cell is a core component for battery pack safety and assembly, and its structural design is crucial to cell safety. However, current battery cells in related technologies have the following drawbacks: 1) Currently, all battery cell covers are flat, and the electrode structures protrude from the cover body, occupying external space during module assembly. The rivet blocks and upper plastic parts in the electrode structures protrude beyond the cover body, offering poor protection and frequently resulting in damage during transportation and assembly. Since the electrode structure directly affects the battery cell's charging and discharging performance, this can lead to performance safety issues and poor appearance. 2) The ends of the battery cell electrode assemblies are all planar, which cannot be well adapted to the cell shape, affecting the cell capacity. 3) The gap between the electrode assembly and the cover assembly results in low space utilization, hindering the improvement of battery cell energy density and making it difficult for the cells to meet the demands of high-capacity, high-rate fast charging. The unbalanced support surfaces of the electrode assembly and cover assembly can easily cause damage to the electrode sheets and excessive movement during the insertion and fixing of the electrode assembly. 4) The demand for high-capacity, high-rate fast charging of battery cells is increasing, and the existing square battery cell structure is insufficient to meet this demand. 5) Due to structural space limitations, the car chassis cannot provide enough space for the battery pack. The conventional square cell structure cannot meet the usage requirements and is difficult to adapt to changes in the shape of the car chassis.

[0028] The following is combined with Figures 1 to 21 The following describes embodiments of the present invention.

[0029] According to an embodiment of the present invention, a battery cell is provided, comprising: a housing structure 1, an electrode assembly structure 2, and a first rotating shaft 3. The housing structure 1 includes two housings 11 arranged adjacent to each other along the Y direction. Each housing 11 has a protrusion 111 and a recess 112 on one side along the Y direction. The protrusion 111 on each housing 11 is disposed in the recess 112 on the other housing 11. Each protrusion 111 has a mounting groove 113 on one side along the X direction facing the other protrusion 111. The electrode assembly structure 2 includes two electrode assembly units 21, which are disposed in the two housings 11. The first rotating shaft 3 is disposed between the two protrusions 111. One end of the first rotating shaft 3 is rotatably inserted into the mounting groove 113 on one protrusion 111, and the other end is rotatably inserted into the mounting groove 113 on the other protrusion 111. The two housings 11 are rotatable relative to each other about the axis of the first rotating shaft 3.

[0030] It should be noted that the X, Y, and Z directions are the X-axis, Y-axis, and Z-axis of a spatial rectangular coordinate system. The two shells 11 of the shell structure 1 are not directly connected, but are indirectly connected only through the first rotating shaft 3, so that the shell structure 1 consists of two relatively rotatable shells 11. The shell structure 1 has a flattened state and a bent state. Specifically, when the shell structure 1 is in the flattened state, the two shells 11 do not rotate relative to each other. At this time, the overall appearance of the shell structure 1 is similar to that of a traditional square battery cell shell. Along the same side of the Z-direction, the large faces of the two shells 11 are in the same plane. After the two shells 11 rotate relative to each other around the axis of the first rotating shaft 3, the shell structure 1 switches to the bent state. At this time, the dihedral angle between the large faces of the two shells 11 is less than 180°, and the two shells 11 are not parallel. The two shells 11 can be rotated relative to each other to the bent state with the required included angle according to the needs of the installation space. For example, at locations with protruding structures on the vehicle chassis, the battery pack can be partially recessed into the battery pack housing to avoid the protruding structure. For the battery cells located at these locations, the angle between the two housings 11 of the cell can be adaptively adjusted according to the shape of the recess on the housing, meeting the requirements for adapting the cell to irregularly shaped spaces and improving the energy density of the battery pack and the entire vehicle. When the housing structure 1 is in a flattened state, the X direction is the length direction of the cell, the Y direction is the width direction of the cell, and the Z direction is the thickness direction of the cell.

[0031] The battery cell of this embodiment is designed with a housing structure 1 consisting of two housings 11 and an electrode assembly structure 2 consisting of two electrode assembly units 21 disposed in the two housings 11. The protrusion 111 on one housing 11 is located in the recess 112 on the other housing 11, making the overall structure of the housing structure 1 compact. The protrusions 111 of the two housings 11 are rotatably connected by a first rotating shaft 3, allowing the two housings 11 to rotate relative to each other around the axis of the first rotating shaft 3. The housing structure 1 adopts a rotating structure design, which allows the battery cell to flexibly adjust its angle according to the shape of the installation space, adapting to different scenario requirements such as the irregular installation space of the car chassis. This is beneficial to improving space utilization and thus effectively improving the overall energy density of the battery pack, solving the problem of poor flexibility and inability to adapt to irregular installation spaces of traditional square battery cells.

[0032] It should be noted that the recessed portion 112 and the protruding portion 111 on the housing 11 are arranged adjacent to each other along the X direction. That is, a protruding portion 111 is provided on one side of the housing 11 along the Y direction, and a recessed portion 112 is formed in the part on that side where no protruding portion 111 is provided. On the same housing 11, there is one protruding portion 111 and one recessed portion 112, making the housing 11 have an axe-shaped structure, which facilitates the mutual cooperation between the two housings 11. Compared with the traditional square battery cell, the protruding portion 111 in this embodiment also helps to increase the structural strength of the housing 11 and further improve the reliability of the battery cell. When the battery cell is in a flattened state, the two housings 11 are centrally symmetrical about the center point of the battery cell in the XY plane.

[0033] Specifically, the two housings 11 include a first housing and a second housing. The first housing has a first protrusion and a first recess on the side facing the second housing along the Y direction, and the second housing has a second protrusion and a second recess on the side facing the first housing along the Y direction. The first protrusion is disposed in the second recess, and the second protrusion is disposed in the first recess. The first protrusion has a first mounting groove on the side facing the second protrusion along the X direction, and the second protrusion has a second mounting groove on the side facing the first protrusion along the X direction. One end of the first rotating shaft 3 is rotatably inserted into the first mounting groove, and the other end is rotatably inserted into the second mounting groove. The two pole group units 21 of the pole group structure 2 include a first pole group and a second pole group. The first pole group is disposed in the first housing, and the second pole group is disposed in the second housing.

[0034] In one embodiment, the first rotating shaft 3 is made of wear-resistant plastic, which can reduce the wear between the first rotating shaft 3 and the inner wall of the mounting groove 113, avoid structural wear after the two housings 11 rotate relative to each other for a long time, and further improve the service life and reliability of the battery cell structure.

[0035] It should be noted that the parameters and their corresponding reference directions mentioned below are all described with the battery cell in a flattened state.

[0036] In one embodiment, further combination Figures 9 to 10 As shown, two protrusions 111 are spaced apart along the X direction, with a distance K between them, where 2 mm ≤ K ≤ 8 mm. If K is less than 2 mm, the distance between the two protrusions 111 is too close, which can easily cause interference when the two housings 11 rotate relative to each other, affecting the rotational flexibility. If K is greater than 8 mm, the space between the two protrusions 111 becomes too large, reducing the overall space utilization of the cell and hindering the improvement of the cell's energy density. Therefore, by limiting K to a value within the range of 2 mm to 8 mm, interference between the two protrusions 111 can be avoided, ensuring the flexibility of the relative rotation of the two housings 11, while also avoiding wasted space, improving the overall space utilization of the cell, and ensuring the cell's energy density.

[0037] Optionally, K can be any value among 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, and 8 mm, or a value between any two of these values.

[0038] In one embodiment, further combination Figure 13 As shown, the dimension of the housing 11 along the Z direction is B, the mounting groove 113 is a cylindrical groove, the first rotating shaft 3 is a cylinder, and the diameter of the mounting groove 113 is D, where 7 mm≤BD≤20 mm, and the units of B and D are both mm.

[0039] It should be noted that the mounting groove 113 is provided on the protrusion 111 and opens towards another protrusion 111 in the X direction. The mounting groove 113 is not in communication with the inner cavity of the housing 11 on which it is provided. The cross-sectional profile of the mounting groove 113 in the YZ plane is circular, where D is the diameter of the circle and B is the thickness of the housing 11 in the Z direction, which is also the thickness of the protrusion 111 in the Z direction.

[0040] If BD is less than 7 mm, the diameter of the mounting groove 113 is too large relative to the thickness of the protrusion 111. Along the Z direction, the edge of the mounting groove 113 is too close to the edge of the protrusion 111, resulting in insufficient edge distance. The solid parts on both sides of the mounting groove 113 on the protrusion 111 are too small, making it difficult to form the shell 11. Furthermore, when the diameter of the mounting groove 113 is large, the diameter of the first rotating shaft 3 located in the mounting groove 113 is correspondingly large, leading to excessive structural cost of the first rotating shaft 3. If BD is greater than 20 mm, the diameter of the mounting groove 113 is too small relative to the thickness of the protrusion 111. Along the Z direction, the edge distance between the mounting groove 113 and the edge of the protrusion 111 is too large, resulting in an excessively small diameter of the first rotating shaft 3 and poor strength, which cannot meet the requirements for cell rotation. During shell rotation, jamming and damage are likely to occur.

[0041] Therefore, by limiting BD to a value within the range of 7 mm to 20 mm, it is possible to ensure that the protrusion 111 has sufficient structural strength, reduce the processing and forming difficulty of the housing 11, and avoid increasing costs due to excessive diameter of the first rotating shaft 3. At the same time, it is possible to ensure that the diameter of the first rotating shaft 3 meets the strength requirements of the rotational connection, avoid jamming and damage during rotation, and ensure the reliability and economy of the battery cell structure.

[0042] Optionally, BD can be any value among 7 mm, 9 mm, 10 mm, 12 mm, 15 mm, 17 mm, and 20 mm, or a value between any two of these values.

[0043] In one embodiment, further combination Figure 12As shown, the protrusion 111 has a dimension of W1 along the Y direction, and the mounting groove 113 has a first center line 1131 parallel to the X direction. The distance between the first center line 1131 and the edge of the protrusion 111 along the Y direction is W2, where W2 / W1 = 0.5, and both W2 and W1 are in mm. W2 refers to the distance between the first center line 1131 and the edge of the protrusion 111 along the Y direction away from the shell body 110. By limiting W2 to half of W1, the mounting groove 113 is located in the middle of the protrusion 111 along the Z direction, which facilitates rotational engagement between the two shells 11.

[0044] In one embodiment, further combination Figure 12 As shown, in the YZ plane, the wall thickness of the casing 11 is T, where 0.3 mm ≤ T ≤ 0.8 mm. If T is less than 0.3 mm, the wall thickness of the casing 11 is too small, the structural strength of the casing 11 is insufficient, and it is prone to deformation under external force, failing to provide sufficient protection for the internal electrode group 21, etc., affecting the safety of the battery cell. If T is greater than 0.8 mm, the wall thickness of the casing 11 is too large, which will increase the weight of the casing 11 itself, reduce the overall energy density of the battery cell, and does not meet the design requirements for lightweight battery cells.

[0045] Therefore, limiting T to a value within the range of 0.3 mm to 0.8 mm can simultaneously take into account the structural strength of the casing 11 and the energy density requirements of the battery cell.

[0046] Optionally, T can be any value among 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, and 0.8 mm, or a value between any two of these values.

[0047] In one embodiment, further combination Figure 12 As shown, the depth of the mounting groove 113 along the X direction is H2, where 20mm ≤ H2 ≤ 80 mm. If H2 is less than 20 mm, the depth of the mounting groove 113 is insufficient, the length of the first rotating shaft 3 inserted into the mounting groove 113 is too short, the fit stability between the first rotating shaft 3 and the mounting groove 113 is poor, and the first rotating shaft 3 is prone to falling off during the relative rotation of the two housings 11, affecting the reliability of the cell structure. If H2 is greater than 80 mm, the mounting groove 113 extends too far along the X direction, occupying too much space inside the housing 11, squeezing the arrangement space of the electrode group 21, thereby reducing the overall capacity and energy density of the cell, making it difficult to meet the design requirements of high capacity cells.

[0048] Therefore, by limiting H2 to a value within the range of 20 mm to 80 mm, it is possible to ensure the stability of the fit between the first rotating shaft 3 and the mounting groove 113, prevent the first rotating shaft 3 from falling off during rotation, and ensure the reliability of the cell structure. At the same time, it is possible to prevent the mounting groove 113 from occupying too much internal space of the cell, ensuring the arrangement space of the electrode group cells 21, which is conducive to improving the capacity of the cell.

[0049] Optionally, H2 can be any value among 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, and 80 mm, or a value between any two of these values.

[0050] In one embodiment, further combination Figure 7 , Figure 13 As shown, the shell 11 also includes a shell body 110. A protrusion 111 is connected to one side of the shell body 110 along the Y direction. The side of the protrusion 111 facing away from the shell body 110 along the Y direction is constructed as an arc-shaped surface 114. A recess 112 is disposed adjacent to the protrusion 111 along the X direction. The side of the shell body 110 facing the recess 112 along the Y direction is constructed as a first plane 115. That is, for the side where the protrusion 111 is provided, the portion of the shell body 110 where the shell body 110 is not provided is constructed as the first plane 115.

[0051] It should be noted that the protrusion 111 on one shell 11 of the shell structure 1 is correspondingly provided with the recess 112 on the other shell 11. By constructing the side of the protrusion 111 away from the shell body 110 as an arc surface 114 and the bottom surface of the recess 112 as a first plane 115, the arc surface 114 on one shell 11 is correspondingly provided with the first plane 115 on the other shell 11. The arc surface 114 can avoid interference with the other shell 11 during rotation, ensuring the smooth relative rotation process between the two shells 11. At the same time, the other side opposite to the arc surface 114 is a planar structure, which can simplify the processing and improve the production efficiency of the shell 11.

[0052] Preferably, the arc surface 114 is a circular arc surface, which has a simple structure and is easy to process.

[0053] In one embodiment, further combination Figure 5 , Figure 8 , Figure 11As shown, the housing 11 also includes a first extension 116 and a second extension 117. The first extension 116 and the second extension 117 are respectively disposed at both ends of the housing body 110 along the X direction. The first extension 116 and the second extension 117 respectively form a receiving space communicating with the inner cavity of the housing body 110. The pole assembly unit 21 includes a pole assembly body 211 and a first boss 213 and a second boss 214. The pole assembly body 211 is disposed inside the housing body 110. The first boss 213 is disposed in the receiving space formed by the first extension 116 and the second boss 214 is disposed in the receiving space formed by the second extension 117. By providing a first extension 116 and a second extension 117 at both ends of the housing 11, the total internal space of the housing 11 is increased. At the same time, the shape of the electrode assembly 21 is adapted to the shape of the housing 11. The electrode assembly 21 has an electrode assembly body 211 disposed in the housing body 110, and a first boss 213 and a second boss 214 disposed in the first extension 116 and the second extension 117 respectively. This allows the electrode assembly 21 to make full use of the internal space of the housing 11, effectively increasing the volume of the electrode assembly 21, thereby improving the overall capacity of the battery cell and meeting the design requirements of high capacity battery cells.

[0054] Further integration Figure 8 As shown, taking the first extension 116 as an example, the shell body 110 has a first sidewall and a second sidewall arranged opposite to each other along the Z direction. The first extension 116 includes two extension portions respectively disposed on the first sidewall and the second sidewall. One extension portion extends out from a part of the first sidewall along the X direction, and the other extension portion extends out from a part of the second sidewall along the X direction. The two extensions are arranged opposite to each other along the Z direction and spaced apart, forming a space between them to accommodate the first protrusion 213. The first extension 116 provides a space for the first protrusion 213 and provides safety protection. The arrangement of the second extension 117 is similar and will not be described again here.

[0055] In one embodiment, further combination Figure 11 As shown, the dimensions of the first extension 116 and the second extension 117 along the X direction are both H1, where 10 mm ≤ H1 ≤ 70 mm. If H1 is less than 10 mm, the dimensions of the first extension 116 and the second extension 117 along the X direction are insufficient, failing to provide enough space for the first boss 213 and the second boss 214, thus limiting the improvement in cell capacity. If H1 is greater than 70 mm, the dimensions of the first extension 116 and the second extension 117 along the X direction are too large, resulting in insufficient structural strength and increasing the processing difficulty and cost of the housing 11. Therefore, limiting H1 to a value within the range of 10 mm to 70 mm can effectively improve the cell capacity while ensuring the structural strength of the housing 11, and simultaneously reducing the processing difficulty and production cost of the housing 11.

[0056] Optionally, H1 can be any value among 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, and 70 mm, or a value between any two of these values.

[0057] In one embodiment, further combination Figure 11 As shown, the first extension 116 is connected to one end of the shell body 110 along the X direction near the recess 112. The dimension of the first extension 116 along the Y direction is L1, and the dimension of the shell body 110 along the Y direction is A1. Wherein, 0.25≤L1 / A1≤0.5, and the units of L1 and A1 are both mm. It should be noted that the end of the housing 11 with the first extension 116 is provided, and the part of the housing 11 without the first extension 116 can be used to set the electrode structure 8. If L1 / A1 is less than 0.25, the size ratio of the first extension 116 on the housing body 110 along the Y direction is insufficient, and the space provided by the first extension 116 for the first boss 213 is limited, which will reduce the increase in cell capacity. In addition, the strength of the first extension 116 is weak and it is easy to be damaged and deformed. If L1 / A1 is greater than 0.5, the size ratio of the first extension 116 on the housing body 110 is too large, which occupies too much space for the electrode structure 8, resulting in insufficient size of the electrode structure 8. This is not conducive to improving the current carrying capacity of the electrode structure 8 and the cell, and cannot meet the current carrying capacity requirements of the fast charging cell.

[0058] Therefore, by limiting L1 / A1 to a value between 0.25 and 0.5, it is possible to effectively increase the cell capacity while ensuring the cell's overcurrent capability and meeting the overcurrent requirements for fast charging.

[0059] Optionally, L1 / A1 can take any value from 0.25, 0.3, 0.35, 0.4, 0.45, 0.5 or a value between any two values.

[0060] In one embodiment, further combination Figure 11 As shown, the dimension of the shell body 110 along the Y direction is A1, and the total dimension of the shell body 110 and the protrusion 111 along the Y direction is A2, where 24 mm ≤ A2 - A1 ≤ 80 mm. Here, A2 - A1 is the dimension of the protrusion 111 along the Y direction. If A2 - A1 is less than 24 mm, the protrusion dimension of the protrusion 111 along the Y direction relative to the shell body 110 is insufficient, which will reduce the increase in cell capacity. Simultaneously, the limited space on the shell 11 for the first rotating shaft 3 results in insufficient strength and easy damage to the first rotating shaft 3. If A2 - A1 is greater than 80 mm, the protrusion dimension of the protrusion 111 along the Y direction relative to the shell body 110 is too large, increasing the difficulty of stamping the shell 11, making it difficult to guarantee the precision of the shell 11, and leading to problems such as rotational jamming and damage after assembly.

[0061] Therefore, by limiting A2-A1 to a value within the range of 24 mm to 80 mm, it is possible to ensure that the protrusion 111 has sufficient size to provide ample space for the first rotating shaft 3, ensuring the structural strength of the first rotating shaft 3, while also ensuring the increase in cell capacity. At the same time, it is possible to reduce the stamping difficulty of the housing 11, ensure the machining accuracy of the housing 11, avoid the problem of jamming or damage when the two housings 11 rotate relative to each other after assembly, and improve the reliability of the cell structure.

[0062] Optionally, the values ​​of A2-A1 can be any one of 24 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, or a value between any two of them.

[0063] In one embodiment, further combination Figure 11 As shown, the second extension 117 is connected to one end of the shell body 110 along the X direction near the protrusion 111. The dimension of the second extension 117 along the Y direction is L2, and the total dimension of the shell body 110 and the first protrusion 111 along the Y direction is A2, where 0.2≤L2 / A2≤0.45, and the units of L2 and A2 are both mm. If L2 / A2 is less than 0.2, the dimension of the second extension 117 along the Y direction is insufficient, providing limited space for the second protrusion 214, which will reduce the increase in cell capacity, and the second extension 117 is weak and easily damaged and deformed; if L2 / A2 is greater than 0.45, the dimension of the second extension 117 along the Y direction is too large, occupying too much space in the electrode structure 8, affecting the overcurrent capacity, and failing to meet the overcurrent requirements of the fast charging cell.

[0064] Therefore, by limiting L2 / A2 to a value between 0.2 and 0.45, it is possible to effectively increase the cell capacity while ensuring that the terminal structure 8 has sufficient space to meet the overcurrent requirements of the fast charging cell.

[0065] Optionally, L2 / A2 can be any value from 0.2, 0.25, 0.3, 0.35, 0.4, 0.45 or a value between any two values.

[0066] In one embodiment, along the X direction, the end of the protrusion 111 away from the recess 112 is flush with the end of the shell body 110 away from the recess 112. This arrangement improves the flatness of the end of the shell 11, facilitates the processing of the shell structure 1, and facilitates the insertion of the electrode assembly 21 into the shell 11.

[0067] In one embodiment, further combination Figure 9 , Figures 14 to 17As shown, the electrode assembly unit 21 also includes a third protrusion 212. The third protrusion 212 is connected to one side of the electrode assembly body 211 along the Y direction, and the third protrusion 212 is disposed in the inner cavity of the protrusion 111, so that the shape of the electrode assembly unit 21 matches the shape of the housing 11, avoiding space waste, increasing the cell capacity, and ensuring the stability of the electrode assembly unit 21 in the housing 11.

[0068] The third protrusion 212 includes a first step portion 2121 and a second step portion 2122. The first step portion 2121 connects the electrode assembly body 211 and the second step portion 2122. The dimension of the second step portion 2122 along the X direction is smaller than the dimension of the first step portion 2121 along the X direction. A clearance space 210 is formed between the first step portion 2121 and the second step portion 2122, and the mounting groove 113 is located in the clearance space 210. With this configuration, the electrode assembly unit 21 can avoid the mounting groove 113 provided on the housing 11 through the clearance space 210, avoiding structural interference between the electrode assembly unit 21 and the mounting groove 113, ensuring that the electrode assembly unit 21 can be smoothly installed into the inner cavity of the housing 11. At the same time, the internal space of the protrusion 111 can be fully utilized to arrange the electrode assembly unit 21, further increasing the capacity of the cell.

[0069] Preferably, along the X direction, the ends of the first step portion 2121 and the second step portion 2122 that are away from the recessed portion 112 of the housing 11 are flush with the end of the pole group body 211, which helps to ensure the regularity of the overall structure of the pole group unit 21 and reduce the assembly difficulty of the pole group unit 21 and the housing 11.

[0070] In one embodiment, further combination Figure 17 As shown, the dimension of the clearance space 210 along the X direction is W, where 20mm≤W≤80mm. If W is less than 20mm, the dimension of the clearance space 210 along the X direction is too small, and the electrode assembly cell 21 is prone to interference with the mounting groove 113, affecting the assembly of the electrode assembly cell 21 with the housing 11; if W is greater than 80mm, the dimension of the clearance space 210 along the X direction is too large, resulting in a reduction in the volume of the third protrusion 212, thereby reducing the overall capacity of the cell.

[0071] Therefore, limiting W to a value within the range of 20 mm to 80 mm can ensure that the clearance space 210 can effectively avoid the mounting slot 113, avoid structural interference, and ensure smooth assembly of the electrode unit 21 and the housing 11. It can also make full use of the internal space of the protrusion 111 to arrange the electrode unit 21, ensure the overall capacity of the cell, and meet the high-capacity design requirements.

[0072] Optionally, W can be any value among 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, and 80 mm, or a value between any two of these values.

[0073] In one embodiment, further combination Figure 17 As shown, 25 mm ≤ a2-a1 ≤ 82 mm. Here, a2-a1 is the dimension of the third boss 212 protruding relative to the pole body 211 along the Y direction. If a2-a1 is less than 25 mm, the dimension of the third boss 212 along the Y direction is insufficient, resulting in insufficient clearance space 210 on the third boss 212 along the Y direction. This limits the space provided for the mounting groove 113 and the first rotating shaft 3, leading to insufficient strength and easy damage to the first rotating shaft 3. If a2-a1 is greater than 82 mm, the dimension of the third boss 212 along the Y direction is too large. Correspondingly, the dimension of the protrusion 111 on the housing 11 along the Y direction is too large, increasing the stamping difficulty of the housing 11, making it difficult to guarantee the precision of the housing 11, and causing rotational jamming and damage after assembly.

[0074] Therefore, by limiting the values ​​of a2-a1 to the range of 25 mm to 82 mm, it is possible to ensure that the third boss 212 has sufficient size to provide ample space for the mounting groove 113 and the first rotating shaft 3, thus ensuring the structural strength of the first rotating shaft 3. At the same time, it is possible to reduce the stamping difficulty of the housing 11, ensure the machining accuracy of the housing 11, avoid jamming and damage when the two housings 11 rotate relative to each other, and further improve the reliability of the battery cell structure.

[0075] Optionally, the values ​​of a2-a1 can be any one of 25 mm, 35 mm, 45 mm, 55 mm, 65 mm, 75 mm, 82 mm, or a value between any two of them.

[0076] In one embodiment, further combination Figure 17 As shown, along the Y direction, the dimension of the electrode assembly body 211 is a1, the total dimension of the electrode assembly body 211 and the third protrusion 212 is a2, and the dimension of the second step portion 2122 is F. Where 0.7 ≤ F / (a2-a1) ≤ 0.9, and the units of F, a2, and a1 are all mm. It should be noted that F is also the dimension of the clearance space 210 along the Y direction. If F / (a2-a1) is less than 0.7, the clearance space 210's proportion along the Y direction on the third protrusion 212 is insufficient, resulting in limited space for the mounting slot 113 and the first rotating shaft 3, leading to insufficient strength and easy damage to the first rotating shaft 3. If F / (a2-a1) is greater than 0.9, the clearance space 210's proportion along the Y direction on the third protrusion 212 is too large, resulting in insufficient overall structural strength of the third protrusion 212, making it prone to deformation and breakage, affecting the structural stability of the electrode assembly cell 21, and thus reducing the cell's service life.

[0077] Therefore, limiting F / (a2-a1) to a value within the range of 0.7 to 0.9 can provide sufficient space for the mounting groove 113 and the first rotating shaft 3, ensuring the structural strength of the first rotating shaft 3, and also ensuring the structural strength of the third boss 212, thereby improving the structural reliability of the electrode group unit 21 and the overall battery cell and extending the battery cell's service life.

[0078] Optionally, F / (a2-a1) can take any value from 0.7, 0.72, 0.75, 0.78, 0.8, 0.82, 0.85, 0.88, 0.9 or a value between any two values.

[0079] In one embodiment, further combination Figure 16 As shown, the dimension of the electrode assembly cell 21 along the Z direction is b, where 20mm ≤ b ≤ 100 mm. If b is less than 20 mm, the thickness of the electrode assembly cell 21 is insufficient, resulting in insufficient overall cell capacity. If b is greater than 100 mm, the thickness of the electrode assembly cell 21 is too large, increasing the overall volume of the cell, which is detrimental to manufacturing and increases the difficulty of heat transfer within the electrode assembly cell 21, causing the internal temperature to rise too quickly during charging and affecting the cell's cycle life. Therefore, limiting b to a value within the range of 20 mm to 100 mm ensures that the cell meets the design requirements for high capacity, reduces manufacturing difficulty, ensures heat dissipation of the electrode assembly cell 21, and extends the cell's cycle life.

[0080] Optionally, the value of b can be any one of 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, or a value between any two of these values.

[0081] In one embodiment, further combination Figure 18 As shown, the dimension of the electrode assembly cell 21 along the X direction is e, where 400mm ≤ e ≤ 980 mm. If e is less than 400 mm, the length of the electrode assembly cell 21 along the X direction is insufficient, resulting in insufficient overall cell capacity; if e is greater than 980 mm, the length of the electrode assembly cell 21 is too large, leading to decreased structural stability and reduced cell production yield. Therefore, limiting e to a value within the range of 400 mm to 980 mm ensures that the cell meets the design requirements for high capacity while maintaining the structural stability of the electrode assembly cell 21, thereby improving the cell production yield.

[0082] Optionally, the value of e can be any one of 400 mm, 450 mm, 500 mm, 550 mm, 600 mm, 650 mm, 700 mm, 750 mm, 800 mm, 850 mm, 900 mm, 950 mm, or 980 mm, or a value between any two of these values.

[0083] In one embodiment, further combination Figure 17 As shown, the dimensions of the first boss 213 and the second boss 214 along the X direction are both H, where 10 mm ≤ H ≤ 70 mm. If H is less than 10 mm, the dimensions of the first boss 213 and the second boss 214 along the X direction are insufficient, resulting in limited improvement in the overall capacity of the battery cell; if H is greater than 70 mm, the dimensions of the first boss 213 and the second boss 214 along the X direction are too large, which will lead to a decrease in the structural strength of the first extension 116 and the second extension 117, while increasing the overall volume of the battery cell, increasing the difficulty of casing processing and production costs.

[0084] Therefore, limiting H to a value within the range of 10 mm to 70 mm can not only increase the overall capacity of the battery cell and meet the high-capacity design requirements, but also ensure the structural strength of the first extension 116 and the second extension 117, and control the processing difficulty and production cost.

[0085] Optionally, H can be any value among 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, and 70 mm, or a value between any two of these values.

[0086] In one embodiment, further combination Figure 17 As shown, along the Y direction, the dimension of the first protrusion 213 is L4, and the dimension of the electrode assembly body 211 is a1, where 0.2≤L4 / a1≤0.5. If L4 / a1 is less than 0.2, the proportion of the first protrusion 213 along the Y direction on the electrode assembly body 211 is insufficient, limiting the increase in cell capacity. The strength of the first protrusion 213 is also weak, which is not conducive to ensuring the structural stability of the electrode assembly unit 21. If L4 / a1 is greater than 0.5, the proportion of the first protrusion 213 along the Y direction on the electrode assembly body 211 is too large, excessively encroaching on the space for the tabs 215 on both sides of the first protrusion 213 along the Y direction. This results in insufficient current carrying capacity of the tabs 215, which in turn affects the overall current carrying capacity of the cell and fails to meet the current carrying capacity requirements of the fast charging cell.

[0087] Therefore, by limiting L4 / a1 to a value within the range of 0.2 to 0.5, we can effectively increase the cell capacity while ensuring that the tab 215 has sufficient space to ensure the overall overcurrent capacity of the cell and meet the usage requirements of fast charging cells.

[0088] Optionally, L4 / a1 can be any value from 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, or a value between any two values.

[0089] In one embodiment, further combination Figure 17As shown, along the Y direction, the third boss 212 has a first side 2123 that is far away from the pole group body 211, the distance from the second boss 214 to the first side 2123 is L3, and the total dimension of the pole group body 211 and the third boss 212 is a2, where 0.36≤L3 / a2≤0.6. If L3 / a2 is less than 0.36, the distance between the edge of the second boss 214 and the edge of the third boss 212 along the Y direction is too close, and the step width difference on the side of the electrode assembly 21 with the second boss 214 is insufficient, which will reduce the installation space and current carrying capacity of the electrode lug 215 and the electrode post structure 8 on that side. At the same time, the dimension of the third boss 212 along the Y direction is insufficient, and the space for setting the first rotating shaft 3 is limited, resulting in insufficient structural strength of the first rotating shaft 3. If L3 / a2 is greater than 0.6, the distance between the edge of the second boss 214 and the edge of the third boss 212 along the Y direction is too far, and the step width difference on the side of the electrode assembly 21 with the second boss 214 is too large. Correspondingly, the dimension of the protrusion 111 on the housing 11 along the Y direction is too large, which increases the stamping difficulty of the housing 11, makes it difficult to guarantee the precision of the housing 11, and causes rotation jamming and damage after assembly.

[0090] Therefore, by limiting L3 / a2 to a value within the range of 0.36 to 0.6, it is possible to ensure the overcurrent capacity of the battery cell and that the first rotating shaft 3 has sufficient space and structural strength. At the same time, it is possible to avoid excessive processing difficulty of the housing 11, ensure the processing accuracy of the housing 11, avoid jamming and damage when the two housings 11 rotate relative to each other, and further improve the overall reliability of the battery cell structure.

[0091] Optionally, L3 / a2 can be any value from 0.36, 0.4, 0.45, 0.5, 0.55, 0.6 or a value between any two values.

[0092] In one embodiment, further combination Figure 17 As shown, the second protrusion 214 has two side surfaces 2141 arranged opposite each other along the Y direction, and the dihedral angle between the two side surfaces 2141 is N, where 20°≤N≤60°. It should be noted that the second protrusion 214 is located at the open end of the housing 11, and the open end of the housing 11 is also provided with a cover plate assembly. The cover plate assembly forms a receiving space corresponding to the second protrusion 214, so that the second protrusion 214 can extend into it. The side surface 2141 of the second protrusion 214 is inclined relative to the XZ plane, and the dimension of the end of the second protrusion 214 away from the electrode group body 211 along the X direction along the Y direction is smaller than the dimension of the end connected to the electrode group body 211 along the Y direction, so that the second protrusion 214 has an overall trapezoidal structure, which facilitates the second protrusion 214 to extend into the receiving space on the corresponding cover plate assembly, thereby facilitating the assembly of the battery cell.

[0093] If N is less than 20°, the included angle between the two sides 2141 of the second boss 214 is too small and the tilt angle of the side 2141 is too large. This will excessively reduce the size of the end of the second boss 214 away from the electrode group body 211, reduce the effective volume of the electrode group cell 21, and is not conducive to increasing the cell capacity. If N is greater than 60°, the included angle between the two sides 2141 of the second boss 214 is too large and the tilt angle of the side 2141 is insufficient. This will reduce the adaptability to the assembly space, make it difficult for the second boss 214 to extend into the accommodating space of the cover plate assembly, and increase the difficulty of cell assembly.

[0094] Therefore, by limiting N to a value within the range of 20° to 60°, the effective volume of the second protrusion 214 can be guaranteed, effectively increasing the cell capacity. At the same time, the assembly difficulty can be reduced by utilizing the inclined side, thereby improving the cell assembly efficiency and pass rate.

[0095] Optionally, N can take any value from 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60° or a value between any two values.

[0096] In one embodiment, along the Y direction, both the first protrusion 213 and the second protrusion 214 are located in the middle of the electrode assembly body 211. The electrode assembly unit 21 has tabs 215 located on both sides of the first protrusion 213 and on both sides of the second protrusion 214 along the Y direction. By providing tabs 215 at the ends of the electrode assembly unit 21 where the first protrusion 213 and the second protrusion 214 are not located along the Y direction, the electrode assembly unit 21 has multiple tabs 215, which enhances the current carrying capacity and facilitates heat dissipation of the tabs 215, preventing excessive temperature during fast charging and improving the safety of the battery cell.

[0097] In one embodiment, both ends of the housing 11 along the X direction are configured as open ends. Specifically, the housing 11 has a first open end 101 and a second open end 102 disposed opposite to each other along the X direction. The first open end 101 is disposed at the end of the housing 11 away from the protrusion 111 along the X direction, and the second open end 102 is disposed at the end of the housing 11 close to the protrusion 111 along the X direction. The first open end 101 of one housing 11 and the second open end 102 of the other housing 11 are located at the same end of the housing structure 1. The electrode assembly 21 is inserted into the housing 11 through the second open end 102. The battery cell also includes two sets of cover plate assemblies, which are respectively disposed at both ends of the battery cell along the X direction. Each set of cover plate assemblies includes a first cover plate 4 and a second cover plate 5. The first cover plate 4 is disposed on the first opening end 101 of one housing 11, and the second cover plate 5 is disposed on the second opening end 102 of the other housing 11. The first cover plate 4 and the second cover plate 5 can rotate relative to each other, and the axis around which the first cover plate 4 and the second cover plate 5 rotate relative to each other is collinear with the axis of the first rotating shaft 3, so as to ensure that the cover plate assemblies do not interfere with the relative rotation between the two housings 11.

[0098] In one embodiment, the first cover plate 4 includes a first cover plate body and a first protrusion. In the X direction, the first protrusion protrudes relative to the first cover plate body in a direction away from the shell body 110. A first receiving cavity 41 is formed on the side of the first protrusion facing the inner cavity of the shell 11 in the X direction. The first cover plate body mates with the shell body 110, and the first protrusion mates with the first extension 116. A first boss 213 of the pole assembly unit 21 is provided in the first receiving cavity 41. The second cover plate 5 includes a second cover plate body and a second protrusion. In the X direction, the second protrusion protrudes relative to the second cover plate body in a direction away from the shell body 110. A second receiving cavity 51 is formed on the side of the second protrusion facing the inner cavity of the shell 11 in the X direction. The second cover plate body mates with the shell body 110, and the second protrusion mates with the second extension 117. A second boss 214 of the pole assembly unit 21 is provided in the second receiving cavity 51.

[0099] In one embodiment, a pole post structure 8 is provided on the first cover plate body located on both sides of the first convex bulge along the Y direction of the first cover plate 4, and a pole post structure 8 is provided on the second cover plate body located on both sides of the second convex bulge along the Y direction of the second cover plate 5. Each pole post structure 8 is electrically connected to the tab 215 on its corresponding electrode group unit. The pole post structure 8 includes a pole post 81 and a riveting block 82. The riveting block 82 is disposed on the side of the cover plate body (first cover plate body / second cover plate body) away from the housing 11. The pole post 81 passes through the cover plate body and is riveted to the riveting block 82. The battery cell also includes a connector 7. A second rotating shaft 6 is fixed on one of the two adjacent riveting blocks 82 along the Y direction on the first cover plate 4 and the second cover plate 5. The second rotating shaft 6 protrudes from the riveting block 82 along the X direction, and the axis of the second rotating shaft 6 is collinear with the axis of the first rotating shaft 3. One end of the connector 7 is rotatably sleeved on the second rotating shaft 6, and the other end is welded to the other riveting block 82. Thus, when the two housings 11 rotate relative to each other around the axis of the first rotating shaft 3, the first cover plate 4 and the second cover plate 5 can rotate synchronously around the axis of the second rotating shaft 6, ensuring rotation reliability. In addition, the connecting piece 7 can also enhance the stability of the cover plate assembly and ensure the smooth progress of the rotation process.

[0100] It is understood that, as an alternative implementation, the connecting piece 7 and the second rotating shaft 6 may not be provided. The first cover plate 4 and the second cover plate 5 are separately provided and adapted to the shape of their respective shell opening ends. In this case, the first cover plate 4 and the second cover plate 5 are not actually connected. During the relative rotation of the two shells 11, the first cover plate 4 and the second cover plate 5 rotate accordingly without interfering with the rotation of the two shells 11.

[0101] Alternatively, the housing 11 can be manufactured by extrusion, stamping, or other methods, which can simplify the manufacturing process of the housing 11.

[0102] In this embodiment, the battery cell has an axe-shaped housing 11 with extensions at both ends. The electrode assembly 21 is adapted to the shape of the housing 11. The first protrusion 213 and the second protrusion 214 at both ends of the electrode assembly 21 can increase the total volume of the electrode assembly 21, thereby improving the battery cell capacity and assembly ratio. At the same time, it can better fix the electrode assembly 21 by cooperating with the receiving cavity on the cover plate assembly. The end of the electrode assembly 21 and the support surface of the cover plate structure have good support balance, avoiding damage and movement of the electrode sheets when pushing the electrode assembly into the housing and fixing it. This reduces the risk of movement and displacement, improves space utilization, and improves process yield and battery cell performance. The first protrusion 213 and the second protrusion 214 can make full use of the space between the electrode assembly 21 and the cover plate, reduce the gap between the electrode assembly and the cover plate, improve space utilization, and improve the battery cell energy density, so that the battery cell can meet the requirements of high capacity and high-rate fast charging.

[0103] Furthermore, the protrusion 111 of the housing 11 can protect the terminal structure 8, effectively preventing the terminal structure 8 from being damaged by impacts, improving the safety protection effect of the cover assembly itself, thereby avoiding problems such as poor charging and discharging performance and poor appearance of the battery cell; the protrusion 111 is provided with a mounting groove 113, which cooperates with the first rotating shaft 3. The two housings 11 are connected through the first rotating shaft 3, so that the housing structure 1 forms a rotating structure composed of two housings 11, which can realize the rotation angle of the two housings 11 to adapt to different scenario requirements, which is conducive to improving the space utilization of the battery pack; the cover assembly and the housing 11 adopt a stepped structure to improve structural strength and precision; standardize the design parameters of the housing 11, reduce design defects, and improve the battery cell capacity, safety, and fast charging performance.

[0104] In this embodiment, the third protrusion 212 on the electrode assembly 21 adopts a two-step design to avoid interference between the electrode assembly 21 and the mounting groove 113 on the housing 11 that accommodates the first rotating shaft 3. The cross-section of the second step 2122, which is away from the electrode assembly body 211, is an arc-shaped structure, while the first step 2121 is a planar structure. Two sets of tabs 215 are provided at both ends of the electrode assembly 21 along the X direction to increase the current carrying capacity of the electrode assembly 21 and facilitate heat dissipation of the tabs, thus avoiding excessive temperature during fast charging. The design parameters of the electrode assembly 21 are standardized, thereby improving the process yield.

[0105] In this embodiment, the battery cells are placed in the battery pack. The terminal structure 8 is welded with connecting pieces on the side facing the outside of the housing 11 to achieve electrical connection between the battery cells. The riveting block 82 of the terminal structure 8 is lower than the protrusions (first protrusion and second protrusion) of the cover plate, which effectively protects against the probability of bumps and knocks during the manufacturing process. After the battery cells are grouped and welded with connecting pieces, the height of the connecting pieces is lower than the position of the cover plate assembly farthest from the housing body, which can save assembly space, improve the module assembly rate, and thus improve the performance indicators of the battery pack (size, capacity, safety, etc.).

[0106] According to an embodiment of the present invention, another aspect provides a battery pack comprising the aforementioned battery cells.

[0107] The following examples and comparative examples verify the impact of different parameter values ​​on cell performance. The parameter settings for the examples and comparative examples are shown in Tables 1 and 3, and the corresponding test results are shown in Tables 2 and 4, respectively.

[0108] Table 1

[0109] Table 2

[0110] It should be noted that "meeting the shell strength requirement" means that the shell strength is greater than 1.2 MPa; "overcurrent capacity" is equal to the product of the cell capacity and the charging rate, with a maximum charging rate of 10C and a commonly used charging rate of 1C~6C; "meeting the cell temperature requirement" means that the cell temperature is ≤60℃ during use. The "qualified cell" mentioned in Table 2 refers to a cell being considered qualified when the shell strength meets the requirements and there are no abnormalities in its fit with the electrode structure and cover assembly, when the cell angle is adjusted, the rotating shaft and mating holes are undamaged, and the cell temperature and capacity meet the design requirements; the cell qualification rate refers to the proportion of qualified cells in a batch to the total number of cells.

[0111] As can be seen from Tables 1 to 2, for the battery cells of Examples 1-1 to 1-6, all parameters of the casing are within the range defined in this application, the strength of the battery cell casing meets the requirements, and there are no abnormalities in the fit with the electrode group cells and the cover plate; when the angle between the two casings of the battery cell is adjusted, the first rotating shaft and the mounting groove are not damaged; the battery cell temperature and capacity meet the design requirements, and the battery cell qualification rate is greater than 98%.

[0112] For the battery cell of Comparative Example 1-1, the value of L1 / A1 is 0.2, which is less than the lower limit of L1 / A1 of 0.25 defined in this application and is not within the range defined in this application. The proportion of the first extension at the end of the casing is insufficient, which reduces the increase in battery cell capacity. The strength of the extension is weak, and the battery cell qualification rate is less than 98%. For the battery cell of Comparative Example 1-2, the value of L1 / A1 is 0.6, which is greater than the upper limit of L1 / A1 of 0.5 defined in this application and is not within the range defined in this application. The proportion of the first extension at the end of the casing is too large, which reduces the overcurrent capacity of the tab and post structure and cannot meet the overcurrent requirements of fast charging cells. The battery cell qualification rate is less than 98%.

[0113] For the cells of Comparative Examples 1-3, the value of A2-A1 is 20 mm, which is less than the lower limit of 24 mm for A2-A1 as defined in this application and is not within the range defined in this application. The protrusion height of the side protrusion of the casing is insufficient, which reduces the increase in cell capacity. At the same time, the space for the first rotating shaft in the casing is limited, resulting in insufficient strength of the first rotating shaft and easy damage. The cell pass rate is less than 98%. For the cells of Comparative Examples 1-4, the value of A2-A1 is 90 mm, which is greater than the upper limit of 80 mm for A2-A1 as defined in this application and is not within the range defined in this application. The protrusion height of the side protrusion of the casing is too large, which increases the difficulty of casing stamping and makes it difficult to guarantee casing precision. This leads to rotation jamming and damage after assembly, and the cell pass rate is less than 98%.

[0114] For the cells of Comparative Examples 1-5, the BD value is 5 mm, which is less than the lower limit of BD of 7 mm defined in this application and is not within the range defined in this application. The edge distance of the casing stamping mounting groove is insufficient, which increases the difficulty of casing forming, increases the structural cost of the rotating part, and the cell qualification rate is less than 98%. For the cells of Comparative Examples 1-6, the BD value is 22 mm, which is greater than the upper limit of BD of 20 mm defined in this application and is not within the range defined in this application. The edge distance of the casing stamping mounting groove is too large, which causes the size and strength of the first rotating shaft to be mismatched with the cell, resulting in rotation jamming and damage after assembly. The cell qualification rate is less than 98%.

[0115] It is evident that when the parameters of the casing are within the range defined in this application, the casing performance is good and the cell qualification rate is high.

[0116] Table 3

[0117] Table 4

[0118] It should be noted that "the strength of the electrode assembly unit meets the requirements" means that the electrode assembly unit has a good appearance and no obvious deformation during hot pressing; and that the support position where the electrode assembly unit abuts against the cover plate assembly will not be squeezed, broken, or deformed during assembly. "Qualified cell" in Table 4 means that the strength of the electrode assembly unit meets the requirements and there are no abnormalities in its fit with the shell and cover plate; the end bosses and side bosses of the electrode assembly unit are undamaged, and the overcurrent of the electrode tabs and the cell capacity meet the design requirements.

[0119] As can be seen from Tables 3 and 4, for the cells of Examples 2-1 to 2-6, all parameters of the electrode group are within the range defined in this application, the strength of the electrode group is met, and there are no abnormalities in the fit with the shell and cover plate; there is no damage to the end boss and side boss of the electrode group, the overcurrent of the electrode tab and the cell capacity meet the design requirements, and the cell qualification rate is greater than 98%.

[0120] For the cell of Comparative Example 2-1, the value of L4 / a1 is 0.15, which is less than the lower limit of L4 / a1 of 0.2 defined in this application and is not within the range defined in this application. The proportion of the first protrusion at the end of the electrode assembly is insufficient, reducing the increase in cell capacity. The strength of the first protrusion position is weak, and the cell qualification rate is less than 98%. For the cell of Comparative Example 2-2, the value of L4 / a1 is 0.6, which is greater than the upper limit of L4 / a1 of 0.5 defined in this application and is not within the range defined in this application. The proportion of the first protrusion at the end of the electrode assembly is too large, reducing the current carrying capacity of the two side tabs and the cover plate, which cannot meet the current carrying capacity requirements of fast charging cells. The cell qualification rate is less than 98%.

[0121] For cells in Comparative Examples 2-3, the value of a2-a1 is 20 mm, which is less than the lower limit of a2-a1 of 25 mm as defined in this application and is not within the range defined in this application. The third protrusion height on the side of the electrode unit is insufficient, reducing the increase in cell capacity. At the same time, the space for the first rotating shaft in the housing is limited, resulting in insufficient strength and easy damage. The cell pass rate is less than 98%. For cells in 2-4, the value of a2-a1 is 90 mm, which is greater than the upper limit of a2-a1 of 82 mm as defined in this application and is not within the range defined in this application. The third protrusion height on the side of the electrode unit is too large, increasing the difficulty of housing stamping and making it difficult to guarantee housing precision. This leads to rotation jamming and damage after assembly, resulting in a cell pass rate of less than 98%.

[0122] For the cells of Comparative Examples 2-5, the value of L3 / a2 is 0.33, which is less than the lower limit of L3 / a2 of 0.36 defined in this application and is not within the range defined in this application. The width difference of the step on the protruding side of the electrode assembly is insufficient, which reduces the space and current carrying capacity of the electrode tab and the electrode post on the cover plate. At the same time, the space for the first rotating shaft in the housing is limited, and the cell pass rate is less than 98%. For the cells of Comparative Examples 2-6, the value of L3 / a2 is 0.64, which is greater than the upper limit of L3 / a2 of 0.6 defined in this application and is not within the range defined in this application. The width difference of the step on the protruding side of the electrode assembly is too large, which increases the difficulty of housing stamping, makes it difficult to guarantee housing precision, and leads to rotation jamming and damage after assembly. The cell pass rate is less than 98%.

[0123] It is evident that when the parameters of the individual cells in the electrode assembly are within the range defined in this application, the cell performance is good and the cell qualification rate is high.

[0124] Unless otherwise stated, the values ​​of all parameters mentioned in this application can be determined using testing methods commonly used in the art. Unless otherwise stated, the test temperature for all parameters is 25°C.

[0125] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that, include: The housing structure includes two housings arranged adjacent to each other along the Y direction. Each housing has a protrusion and a recess on one side along the Y direction. The protrusion on each housing is disposed in the recess on the other housing. Each protrusion has a mounting groove on one side along the X direction facing the other protrusion. The electrode assembly structure includes two electrode assembly units, which are respectively disposed in two housings; A first rotating shaft is disposed between the two protrusions. One end of the first rotating shaft is rotatably inserted into a mounting groove on one of the protrusions, and the other end is rotatably inserted into a mounting groove on the other protrusion. The two housings can rotate relative to each other about the axis of the first rotating shaft.

2. The battery cell according to claim 1, characterized in that, The two protrusions are spaced apart along the X direction, and the distance between them is K, where 2 mm ≤ K ≤ 8 mm; And / or, the dimension of the housing along the Z direction is B, the mounting groove is a cylindrical groove, and the diameter of the mounting groove is D, wherein 7 mm ≤ BD ≤ 20 mm; And / or, the protrusion has a dimension of W1 along the Y direction, the mounting groove has a first center line parallel to the X direction, and the distance between the first center line and the edge of the protrusion along the Y direction is W2, where W2 / W1=0.5; And / or, in the YZ plane, the wall thickness of the shell is T, where 0.3 mm ≤ T ≤ 0.8 mm; And / or, the depth of the mounting groove along the X direction is H2, wherein 20 mm ≤ H2 ≤ 80 mm.

3. The battery cell according to claim 1, characterized in that, The shell also includes a shell body, the protrusion is connected to one side of the shell body along the Y direction, the protrusion is constructed as an arc-shaped surface on the side of the shell body away from the shell body along the Y direction, the recess is disposed adjacent to the protrusion along the X direction, and the side of the shell body facing the recess along the Y direction is constructed as a first plane.

4. The battery cell according to claim 3, characterized in that, The housing further includes a first extension and a second extension, which are respectively disposed at both ends of the housing body along the X direction. The first extension and the second extension each form a receiving space communicating with the inner cavity of the housing body. The electrode assembly includes an electrode assembly body and a first protrusion and a second protrusion. The electrode assembly body is disposed inside the shell body. The first protrusion is disposed in the receiving space formed by the first extension, and the second protrusion is disposed in the receiving space formed by the second extension.

5. The battery cell according to claim 4, characterized in that, The dimensions of the first extension and the second extension along the X direction are both H1, wherein 10 mm ≤ H1 ≤ 70 mm; And / or, the first extension is connected to one end of the shell body along the X direction near the recess, the first extension has a dimension L1 along the Y direction, and the shell body has a dimension A1 along the Y direction, wherein 0.25≤L1 / A1≤0.5; And / or, the dimension of the shell body along the Y direction is A1, and the total dimension of the shell body and the protrusion along the Y direction is A2, wherein 24 mm ≤ A2 - A1 ≤ 80 mm; And / or, the second extension is connected to one end of the shell body along the X direction near the protrusion, the second extension has a dimension of L2 along the Y direction, and the total dimension of the shell body and the first protrusion along the Y direction is A2, wherein 0.2≤L2 / A2≤0.45; And / or, along the X direction, the end of the protrusion away from the recess is flush with the end of the shell body away from the recess.

6. The battery cell according to any one of claims 4 or 5, characterized in that, The electrode assembly unit also includes a third protrusion, which is connected to one side of the electrode assembly body along the Y direction and is disposed in the inner cavity of the protrusion. The third protrusion includes a first step portion and a second step portion. The first step portion is connected between the pole assembly body and the second step portion. The dimension of the second step portion along the X direction is smaller than the dimension of the first step portion along the X direction. A clearance space is formed between the first step portion and the second step portion, and the mounting groove is located in the clearance space.

7. The battery cell according to claim 6, characterized in that, The clearance space has a dimension of W along the X direction, where 20 mm ≤ W ≤ 80 mm; And / or, along the Y direction, the size of the pole group body is a1, the total size of the pole group body and the third boss is a2, and the size of the second step is F, wherein 0.7≤F / (a2-a1)≤0.9, and / or, 25 mm≤a2-a1≤82 mm; And / or, the dimension of the electrode assembly unit along the Z direction is b, where 20 mm ≤ b ≤ 100 mm; And / or, the dimension of the electrode assembly unit along the X direction is e, where 400 mm ≤ e ≤ 980 mm.

8. The battery cell according to claim 6, characterized in that, The dimensions of the first boss and the second boss along the X direction are both H, where 10 mm ≤ H ≤ 70 mm; And / or, along the Y direction, the dimension of the first boss edge is L4, and the dimension of the pole group body is a1, wherein 0.2≤L4 / a1≤0.5; And / or, along the Y direction, the third protrusion has a first side away from the pole group body, the distance from the second protrusion to the first side is L3, and the total dimension of the pole group body and the third protrusion is a2, wherein 0.36≤L3 / a2≤0.

6.

9. The battery cell according to claim 6, characterized in that, The second boss has two sides arranged opposite each other along the Y direction, and the dihedral angle between the two sides is N, wherein 20°≤N≤60°; And / or, along the Y direction, the first boss and the second boss are both located in the middle of the electrode assembly body, and the electrode assembly unit is provided with electrode tabs on both sides of the first boss along the Y direction and on both sides of the second boss along the Y direction.

10. A battery pack, characterized in that, include: The battery cell according to any one of claims 1 to 9.

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