Battery

Abstract

The invention belongs to the technical field of batteries, and discloses a battery which comprises a pole group and a cover plate assembly, and the pole group is connected with a tab; the cover plate assembly comprises a pole, a cover plate body and first plastic, the pole is electrically connected with the tab, and the first plastic is arranged on the side, facing the pole group, of the cover plate body; the width of the pole group is W1, the width of the first plastic cement is W2, the width of the cover plate body is W3, W1 > = W2, and W3 > = W2. Therefore, the width W1 of the pole group and the width W3 of the cover plate body are both greater than the width W2 of the first plastic cement 22, so that the pole group, the first plastic cement and the cover plate can be more reasonably matched in size, the assembly quality is improved, the assembly interference is avoided, and the battery cell assembly yield and the safety performance are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a battery. Background Art

[0002] Lithium batteries occupy an important position in the field of modern high-performance batteries due to their advantages such as high working voltage, high specific energy, large capacity, low self-discharge, good cycle performance, long service life, light weight, and small size.

[0003] The long-core lithium-ion battery includes a cover plate, a housing, a bare-core insulating film, a pole group, an electrolyte, etc. The cover plate includes structures such as pole columns, light aluminum sheets, plastics, explosion-proof valves, etc. After the light aluminum sheet is welded to the housing, it forms a sealed space with certain mechanical strength to protect the pole group and realizes the assembly of the housing and the cover. The pole group is welded to the pole columns on the cover plate through pole ears to achieve electrical connection, so that the pole columns lead out the current inside the battery cell. The plastic is arranged between the pole group and the light aluminum sheet. On the one hand, it plays an insulating role and provides an insulating space to protect the pole ears. On the other hand, it can abut against the pole group and realize the press-fitting and fixing of the pole group to prevent the pole group from shaking inside the housing.

[0004] The long-core lithium-ion battery usually adopts a design with the positive and negative pole ears leading out from both sides. Due to the long battery cell, when the pole group is assembled into the housing, if the dimensions of the pole group, plastic, and cover plate do not match reasonably, it may cause difficulties in assembling into the housing, resulting in the bare-core insulating film being scratched by the housing or the cover plate, and may also cause problems such as the housing being damaged by the cover plate and the plastic not being assembled in place. After the battery cell is filled with electrolyte, the expansion of the pole group may cause the thermally melted connection part between the bare-core insulating film and the plastic to be pulled and fall off and break, resulting in a decrease or even failure of the insulating performance of the bare-core insulating film and the plastic, affecting the assembly yield and safety performance of the battery cell. Summary of the Invention

[0005] The purpose of the present invention is to provide a battery to solve the problems of poor effect of assembling the pole group into the housing, low assembly yield of the battery cell, and low safety performance.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] A battery includes a pole group and a cover plate assembly. The pole group is connected with a pole ear; the cover plate assembly includes a pole column, a cover plate body, and a first plastic. The pole column is electrically connected with the pole ear, and the first plastic is arranged on the side of the cover plate body facing the pole group; the width of the pole group is W1, the width of the first plastic is W2, and the width of the cover plate body is W3, and W1≥W2, W3≥W2 are satisfied.

[0008] Preferably, 12.5mm≤W1≤49mm; and / or, the height of the pole group is L1, and 70mm≤L1≤210mm is satisfied.

[0009] Preferably, the height of the electrode group is L1, and 4.2 ≤ L1 / W1 ≤ 5.6 is satisfied.

[0010] Preferably, 0 mm ≤ W1 - W2 ≤ 3 mm, the height of the electrode group is L1, the length of the first plastic is L2, and -1 mm ≤ L1 - L2 ≤ 5 mm is satisfied.

[0011] Preferably, the length of the first plastic is L2, the length of the cover plate body is L3, and L3 > L2 is satisfied.

[0012] Preferably, 3.5 mm ≤ L3 - L2 ≤ 7 mm.

[0013] Preferably, 3 mm ≤ W3 - W2 ≤ 7 mm.

[0014] Preferably, the length direction of the cover plate body is parallel to the height direction of the electrode group, and the cover plate body is arranged at the end of the electrode group.

[0015] Preferably, along the height direction of the cover plate body, the projection of the first plastic is located inside the projection of the cover plate body; and / or, the first plastic is provided with a boss, and along the height direction of the first plastic, the projection of the boss is located inside the projection of the first plastic.

[0016] Preferably, the battery further includes an insulating film and a housing, the insulating film is coated on the electrode group and arranged between the housing and the electrode group, and the position of the insulating film corresponding to the end of the electrode group is connected to the first plastic.

[0017] Advantages of the present invention:

[0018] A battery includes an electrode group and a cover plate assembly. The electrode group is connected with an electrode tab; the cover plate assembly includes a pole column, a cover plate body and a first plastic. The pole column is electrically connected with the electrode tab, and the first plastic is arranged on the side of the cover plate body facing the electrode group; the width of the electrode group is W1, the width of the first plastic is W2, and the width of the cover plate body is W3, and W1 ≥ W2, W3 ≥ W2 are satisfied.

[0019] In this way, by making the width W1 of the electrode group and the width W3 of the cover plate body both greater than the width W2 of the first plastic, the cooperation of the sizes of the electrode group, the first plastic and the cover plate can be made more reasonable during the assembly process, the difficulty of entering the housing can be reduced, the interference between the first plastic and the electrode group and the cover plate body can be avoided, the stability of the electrode group inside the housing can be improved, and the insulating performance of the first plastic can be maintained, so as to improve the assembly yield and safety performance of the battery cell. Brief Description of the Drawings

[0020] Figure 1 is an exploded view of the battery in an embodiment of the present invention;

[0021] Figure 2 It is a partial decomposition diagram of the battery in an embodiment of the present invention.

[0022] In the figure:

[0023] 1. Pole group; 11. Insulating film; 2. Cover plate assembly; 21. Cover plate body; 211. Pole post; 22. First plastic; 221. Boss; 3. Housing. Detailed implementation manners

[0024] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. In addition, it should be noted that for the convenience of description, only parts related to the present invention rather than all structures are shown in the drawings.

[0025] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0026] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "above", and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or only means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "below", and "under" the second feature includes that the first feature is directly below and obliquely below the second feature, or only means that the horizontal height of the first feature is lower than that of the second feature.

[0027] In the description of this embodiment, the orientation or positional relationship terms such as "above", "below", "right", etc. are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0028] Refer to Figure 1 and Figure 2, the present invention provides a battery, comprising a pole group 1 and a cover plate assembly 2. The pole group 1 is connected with pole tabs (not shown in the figure); the cover plate assembly 2 includes a pole post 211, a cover plate body 21 and a first plastic 22. The pole post 211 is electrically connected with the pole tabs, and the first plastic 22 is disposed on a side of the cover plate body 21 facing the pole group 1; the width of the pole group 1 is W1, the width of the first plastic 22 is W2, and the width of the cover plate body 21 is W3, and W1≥W2, W3≥W2 are satisfied.

[0029] In this embodiment, pole tabs are disposed at both ends of the pole group 1. The length direction of the first plastic 22 is parallel to the length direction of the cover plate body 21, and the pole post 211 is fixedly connected with the cover plate body 21.

[0030] Thus, by making the width W1 of the pole group 1 and the width W3 of the cover plate body 21 both greater than the width W2 of the first plastic 22, the assembly quality of the pole group 1, the first plastic 22 and the cover plate body 21 can be improved during the assembly process, so that the first plastic 22 is not easily interfered with the pole group 1 and the cover plate body 21, and the misalignment of the first plastic 22 during the assembly process and the resulting shaking of the pole group 1 or damage to the insulating film 11 are avoided, enabling the first plastic 22 to achieve the insulating connection between the cover plate body 21 and the pole group 1, and improving the assembly yield and safety performance of the battery cell.

[0031] It can be understood that the width W3 of the cover plate body 21 can be greater than or less than the width W1 of the pole group 1, or can be equal to the width W1 of the pole group 1, which will not be listed in detail here.

[0032] Refer to Figure 2 , in some embodiments, 12.5mm≤W1≤49mm, the height of the pole group 1 is L1, and 70mm≤L1≤210mm is satisfied.

[0033] In this embodiment, the width W1 of the pole group 1 can be any value between 12.5mm and 49mm or the range between any two values, such as 12.5mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 49mm, etc.; the height L1 of the pole group 1 can be any value between 70mm and 210mm or the range between any two values, such as 70mm, 80mm, 90mm, 100mm, 120mm, 150mm, 170mm, 200mm, 210mm, etc.

[0034] Thus, the electrode group 1 has a suitable width, enabling it to smoothly enter the housing and be stably disposed inside the housing 3, preventing interference between the electrode group 1 covered with the insulating film 11 and the housing 3 and rupture of the insulating film 11. After entering the housing, it can be stably supported by the first plastic 22, enhancing the structural strength at the connection between the first plastic 22 and the electrode group 1. Also, it can prevent the connection between the insulating film 11 and the first plastic 22 from being pulled when the electrode group 1 expands after the battery cell is filled with liquid, improving the assembly yield and safety performance of the battery cell.

[0035] It can be understood that the width W1 of the electrode group 1 cannot be too small. If it is too small, the connection stability between the first plastic 22 and the electrode group 1 will deteriorate, leading to looseness between the first plastic 22 and the electrode group 1, affecting the stability of the battery, and increasing the gap between the electrode group 1 and the housing 3, raising the risk of damage to the electrode group 1. Nor can the width W1 of the electrode group 1 be too large. If it is too large, the resistance to entering the housing will increase, making it impossible to smoothly enter the housing 3 during the assembly process due to deformation or inclination, causing the insulating film 11 to rupture, reducing the assembly efficiency, increasing the risk of battery deformation, and resulting in insufficient structural strength at the connection with the first plastic 22, reducing the structural strength at the connection between the first plastic 22 and the electrode group 1.

[0036] Furthermore, the height L1 of the electrode group 1 cannot be too small. If it is too small, it will be difficult for the electrode group 1 to be supported by the housing 3, causing the electrode group 1 to easily shake inside the housing 3, and affecting the battery capacity, resulting in insufficient welding area between the tab and the terminal 211, reducing the electrical conductivity and stability of the battery. Nor can the height L1 of the electrode group 1 be too large. If it is too large, it will increase the risk of assembly interference between the electrode group 1 and the first plastic 22 and the housing 3.

[0037] It can be understood that the width W1 and the height L1 of the electrode group 1 can be adjusted according to actual needs, and will not be elaborated here.

[0038] Refer to Figure 2 , in some embodiments, 4.2 ≤ L1 / W1 ≤ 5.6.

[0039] In this embodiment, the ratio of the height L1 to the width W1 of the electrode group 1 can be any value between 4.2 and 5.6 or the range between any two values, such as 4.2, 4.5, 4.7, 5, 5.3, 5.6, etc.

[0040] Thus, by setting the ratio of the height L1 to the width W1 of the electrode group 1, the electrode group 1 can have strong stability, improving the assembly yield of the electrode group 1 entering the housing, preventing the electrode group 1 from being scratched by the housing 3 or the cover plate, reducing the impact on the first plastic 22 when the electrode group 1 expands, further reducing the deformation of the first plastic 22, maintaining the insulating performance of the first plastic 22, and improving the assembly yield and safety performance of the battery cell.

[0041] It can be understood that the ratio of the height L1 of the electrode group 1 to the width W1 of the electrode group 1 cannot be too small. If it is too small, it will affect the overall energy density of the battery, affect the battery capacity, and make it difficult for the first plastic 22 to cover the insulating area, resulting in a decrease in insulation performance and an increase in the risk of short circuit. The ratio of the height L1 of the electrode group 1 to the width W1 of the electrode group 1 cannot be too large. If it is too large, it will affect the structural stability of the electrode group 1, reduce the structural strength of the electrode group 1, increase the difficulty of inserting into the case, and affect the reliability and safety performance of the battery.

[0042] Refer to Figure 2 , in some embodiments, 0mm ≤ W1 - W2 ≤ 3mm, the length of the first plastic 22 is L2, and -1mm ≤ L1 - L2 ≤ 5mm is satisfied.

[0043] In this embodiment, the difference between the width W1 of the electrode group 1 and the width W2 of the first plastic 22 can be any value between 0 - 3mm or the range between any two values, such as 0mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, etc.; the difference between the height L1 of the electrode group 1 and the length L2 of the first plastic 22 can be any value between -1mm - 5mm or the range between any two values, such as -1mm, 0mm, 1mm, 2mm, 3mm, 4mm, 5mm, etc.

[0044] In this way, while the first plastic 22 can provide insulation protection for the electrode group 1, it will not exceed the edge of the electrode group 1, enabling the first plastic 22 to be in close contact with the electrode group 1 and providing stable support for the electrode group 1, avoiding the exposure of the electrode group 1 due to the too narrow first plastic 22, improving the insulation performance of the first plastic 22, and not being too wide to cause damage to the electrode group 1 during the process of inserting into the case. After the battery core is injected with liquid, the electrode group 1 expands. Due to the small size difference between the electrode group 1 and the first plastic 22, the force at the connection between the electrode group 1 and the first plastic 22 is uniform and has sufficient connection strength. The connection between the electrode group 1 and the first plastic 22 is not easily pulled due to the expansion of the electrode group 1, improving the assembly yield rate and safety performance of the battery.

[0045] It can be understood that the difference between the width W1 of the electrode group 1 and the width W2 of the first plastic 22 cannot be too small. If it is too small, the width of the first plastic 22 will be too large, increasing the overall size of the cover assembly 2. During shell insertion, there will be assembly interference with the housing 3 and the cover body 21, and extrusion deformation will occur, increasing the assembly difficulty. The difference between the width W1 of the electrode group 1 and the width W2 of the first plastic 22 cannot be too large either. If it is too large, the first plastic 22 will not be able to cover the end of the electrode group 1, resulting in a decrease in insulation performance, increasing the risk of short circuit. Moreover, the structural strength of the first plastic 22 is relatively small, making it difficult to provide sufficient support for the electrode group 1, which may cause the electrode group 1 to slide inside the housing 3, affecting the stability of the battery. And during the process of inserting the electrode group 1 into the shell, it increases the risk of direct contact between the electrode group 1 and the housing 3 or the cover body 21, increasing the probability of damage to the electrode group 1 and the insulating film 11 coated on the electrode group 1, affecting the safety of the battery.

[0046] Refer to Figure 2 , in some embodiments, the length of the cover body 21 is L3, and L3 > L2 is satisfied.

[0047] In this embodiment, the center of the first plastic 22 coincides with the center of the cover body 21, that is, the distance between the edge of the first plastic 22 and the edge of the cover body 21 remains constant.

[0048] In this way, the cover body 21 can cover the first plastic 22 and provide sufficient support for the first plastic 22, thereby increasing the overall structural strength of the cover assembly 2, avoiding bending or offset of the first plastic 22 during the assembly and shell insertion process and pulling and cracking at the connection between the first plastic 22 and the electrode group 1 when the electrode group 1 expands, improving the assembly quality, and facilitating the centering of the first plastic 22 on the end face of the electrode group 1, reducing the shell insertion difficulty. After the first plastic 22 and the electrode group 1 are successfully inserted into the shell, the cover body 21 can protect the first plastic 22 and the electrode group 1 in the housing 3, avoiding the influence of external impact, and improving the yield rate and safety performance of the battery cell assembly.

[0049] It can be understood that the length L3 of the cover body 21 cannot be less than or equal to the length L2 of the first plastic 22, otherwise the edge of the first plastic 22 will be flush with or protrude from the edge of the cover body 21, making the first plastic 22 prone to being extruded by external forces and deformed during the assembly process, affecting the insulation performance, and will crush the electrode group 1, reducing the connection stability and connection strength at the connection between the electrode group 1 and the first plastic 22, and affecting the yield rate of the battery cell assembly.

[0050] Refer to Figure 2 , in some embodiments, 3.5mm ≤ L3 - L2 ≤ 7mm.

[0051] In this embodiment, the difference between the length L3 of the cover body 21 and the length L2 of the first plastic 22 can be any value between 3.5mm-7mm or a range between any two values, such as 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, etc.

[0052] In this way, by limiting the range of the difference between the length L3 of the cover body 21 and the length L2 of the first plastic 22, the cover body 21 can fully cover and support the first plastic 22, thereby increasing the longitudinal stability during the assembly process, and preventing the first plastic 22 from bending, warping or deflecting during the assembly process, thereby ensuring that the first plastic 22 has sufficient insulation performance, reducing the difficulty of entering the shell, and preventing the electrode group 1 from being scratched or crushed due to assembly interference. After the battery cell is filled with liquid, the electrode group 1 expands. Since the cover assembly 2 has sufficient structural strength, the connection between the first plastic 22 and the electrode group 1 is not easily pulled due to the pressure generated by the expansion, thereby improving the assembly yield and safety performance of the battery cell.

[0053] It can be understood that the difference between the length L3 of the cover body 21 and the length L2 of the first plastic 22 cannot be too small. If it is too small, the supporting effect of the cover body 21 on the first plastic 22 will be weakened, causing the first plastic 22 to be deformed due to uneven force during assembly, affecting the insulation performance of the first plastic 22, increasing the difficulty of assembly, and increasing the assembly defect rate. The difference between the length L3 of the cover body 21 and the length L2 of the first plastic 22 cannot be too large. If it is too large, the protruding area of the cover body 21 relative to the first plastic 22 will be too large, reducing the compactness of the overall structure of the battery, increasing the manufacturing cost, and causing uneven force on the cover body 21, affecting the press-fitting stability of the electrode group 1, and reducing the safety performance of the battery cell.

[0054] See also Figure 2 , in some embodiments, 3mm≤W3-W2≤7mm.

[0055] In this embodiment, the difference between the width W3 of the cover body 21 and the width W2 of the first plastic 22 can be any value between 3 mm and 7 mm or a range between any two values, such as 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, etc.

[0056] In this way, by limiting the range of the difference between the width W3 of the cover body 21 and the width W2 of the first plastic 22, the cover body 21 and the first plastic 22 can have sufficient structural strength in the width direction of the electrode group 1, thereby increasing the lateral stability during assembly, avoiding lateral shaking of the electrode group 1, and keeping the electrode group 1 stable inside the shell 3. It is not easy to cause assembly interference with the electrode group 1, reducing the difficulty of entering the shell, and improving the assembly yield and safety performance of the battery cell.

[0057] It can be understood that the difference between the width W3 of the cover plate body 21 and the width W2 of the first plastic 22 should not be too small. If it is too small, the lateral stability of the cover plate assembly 2 will decrease, which is not conducive to assembling to the electrode group 1, increasing the risk of assembly interference when the first plastic 22 is inserted into the shell and causing damage to the electrode group 1. Nor should the difference between the width W3 of the cover plate body 21 and the width W2 of the first plastic 22 be too large. If it is too large, the overall size of the battery will increase, increasing the manufacturing cost, and stress concentration will occur in the cover plate body 21 during the assembly process, causing the electrode group 1 to be subjected to uneven pressure when fixed by the first plastic 22, increasing the risk of deformation of the first plastic 22 and the electrode group 1, reducing the insulation performance and the yield of the cell assembly.

[0058] To verify the rationality of the ranges of the height L1 of the electrode group 1, the width W1 of the electrode group 1, the length L2 of the first plastic 22, the width W2 of the first plastic 22, the length L3 of the cover plate body 21, and the width W3 of the cover plate body 21, as shown in Table 1 and Table 2, this embodiment provides fifteen sets of examples and eight sets of comparative examples for illustration. By designing the electrode group 1, the first plastic 22, and the cover plate body 21 with different sizes, the cell assembly effect is verified.

[0059] Table 1

[0060] Serial number L1 / mm W1 / mm L2 / mm W2 / mm L3 / mm W3 / mm Test result Example 1 76 13 77 13 82 17 There is no problem of scratching the insulating film of the bare cell during cell assembly. After the finished cell is filled with liquid and disassembled, no phenomenon of thermal melting point detachment of the insulating film of the bare cell is found, and the insulation of the cell is normal Example 2 76 13 76 12 80 17 There is no problem of scratching the insulating film of the bare cell during cell assembly. After the finished cell is filled with liquid and disassembled, no phenomenon of thermal melting point detachment of the insulating film of the bare cell is found, and the insulation of the cell is normal Example 3 76 13 75 12 82 17 There is no problem of scratching the insulating film of the bare cell during cell assembly. After the finished cell is filled with liquid and disassembled, no phenomenon of thermal melting point detachment of the insulating film of the bare cell is found, and the insulation of the cell is normal Example 4 76 13 74 11 80 17 There is no problem of scratching the insulating film of the bare cell during cell assembly. After the finished cell is filled with liquid and disassembled, no phenomenon of thermal melting point detachment of the insulating film of the bare cell is found, and the insulation of the cell is normal Example 5 76 13 73 12 80 17 There is no problem of scratching the insulating film of the bare cell during cell assembly. After the finished cell is filled with liquid and disassembled, no phenomenon of thermal melting point detachment of the insulating film of the bare cell is found, and the insulation of the cell is normal Example 6 76 13 72 10 78 17 There is no problem of scratching the insulating film of the bare cell during cell assembly. After the finished cell is filled with liquid and disassembled, no phenomenon of thermal melting point detachment of the insulating film of the bare cell is found, and the insulation of the cell is normal Example 7 78 13 73 10 80 17 There is no problem of scratching the insulating film of the bare cell during cell assembly. After the finished cell is filled with liquid and disassembled, no phenomenon of thermal melting point detachment of the insulating film of the bare cell is found, and the insulation of the cell is normal Example 8 200 40 200 40 204 43 There is no problem of scratching the insulating film of the bare cell during cell assembly. After the finished cell is filled with liquid and disassembled, no phenomenon of thermal melting point detachment of the insulating film of the bare cell is found, and the insulation of the cell is normal Example 9 200 40 199 39 204 43 There is no problem of scratching the insulating film of the bare cell during cell assembly. After the finished cell is filled with liquid and disassembled, no phenomenon of thermal melting point detachment of the insulating film of the bare cell is found, and the insulation of the cell is normal Example 10 200 40 199 40 204 43 There is no problem of scratching the insulating film of the bare cell during cell assembly. After the finished cell is filled with liquid and disassembled, no phenomenon of thermal melting point detachment of the insulating film of the bare cell is found, and the insulation of the cell is normal Example 11 200 40 198 40 204 43 There is no problem of scratching the insulating film of the bare cell during cell assembly. After the finished cell is filled with liquid and disassembled, no phenomenon of thermal melting point detachment of the insulating film of the bare cell is found, and the insulation of the cell is normal Example 12 200 40 197 38 204 43 There is no problem of scratching the insulating film of the bare cell during cell assembly. After the finished cell is filled with liquid and disassembled, no phenomenon of thermal melting point detachment of the insulating film of the bare cell is found, and the insulation of the cell is normal Example 13 200 40 196 38 200 43 There is no problem of scratching the insulating film of the bare cell during cell assembly. After the finished cell is filled with liquid and disassembled, no phenomenon of thermal melting point detachment of the insulating film of the bare cell is found, and the insulation of the cell is normal Example 14 200 39 195 37 202 43 There is no problem of scratching the insulating film of the bare cell during cell assembly. After the finished cell is filled with liquid and disassembled, no phenomenon of thermal melting point detachment of the insulating film of the bare cell is found, and the insulation of the cell is normal Example 15 198 40 195 37 200 43 There is no problem of scratching the insulating film of the bare cell during cell assembly. After the finished cell is filled with liquid and disassembled, no phenomenon of thermal melting point detachment of the insulating film of the bare cell is found, and the insulation of the cell is normal

[0061] It can be seen from Examples 1 to 15 in Table 1 that when 0mm ≤ W1 - W2 ≤ 3mm and -1mm ≤ L1 - L2 ≤ 5mm are satisfied, the problem of the insulating film 11 being scratched during cell assembly can be solved. After the cell is filled with liquid, the heat-sealed connection between the insulating film 11 and the first plastic 22 will not be pulled off due to the expansion of the electrode group 1, and the insulation performance of the finished cell is normal, with good assembly yield and safety performance.

[0062] Table 2

[0063] Serial number L1 / mm W1 / mm L2 / mm W2 / mm L3 / mm W3 / mm Test result Comparative example 1 76 13 77 14 82 17 The size of the first plastic is not appropriate, and the scratching ratio of the insulating film of the bare cell when the electrode group enters the shell is about 0.452%, and the shell pressing ratio is 0.10% Comparative example 2 76 13 78 13 82 17 The size of the first plastic is not appropriate, and the scratching ratio of the insulating film of the bare cell when the electrode group enters the shell is about 0.385%, and the shell pressing ratio is 0.11% Comparative example 3 76 13 72 9 78 16 There is no abnormality in the insertion of the electrode assembly into the case, but after electrolyte injection, when the battery cell is disassembled, it is found that the heat melting point of the insulation film of the bare battery cell has fallen off. Comparative Example 4 78 13 72 10 78 17 There is no abnormality in the insertion of the electrode assembly into the case, but after electrolyte injection, when the battery cell is disassembled, it is found that the heat melting point of the insulation film of the bare battery cell has fallen off. Comparative Example 5 200 40 202 38 204 43 The size of the first plastic is inappropriate. The scratching ratio of the insulation film of the bare battery cell during the insertion of the electrode assembly into the case is about 0.375%, and at the same time, the crushing ratio of the case is 0.098%. Comparative Example 6 200 40 196 41 200 43 The size of the first plastic is inappropriate. The scratching ratio of the insulation film of the bare battery cell during the insertion of the electrode assembly into the case is about 0.293%, and at the same time, the crushing ratio of the case is 0.121%. Comparative Example 7 201 39 195 37 202 43 There is no abnormality in the insertion of the electrode assembly into the case, but after electrolyte injection, when the battery cell is disassembled, it is found that the heat melting point of the insulation film of the bare battery cell has fallen off. Comparative Example 8 198 41 195 37 200 43 There is no abnormality in the insertion of the electrode assembly into the case, but in the finished battery cell, it is found that the insulation of the cover plate assembly is poor.

[0064] It can be seen from Comparative Examples 1 to 8 in Table 2 that when the height L1 of the electrode group 1, the width W1 of the electrode group 1, the length L2 of the first plastic 22, and the width W2 of the first plastic 22 do not satisfy 4.2 ≤ L1 / W1 ≤ 5.6, 0mm ≤ W1 - W2 ≤ 3mm, and -1mm ≤ L1 - L2 ≤ 5mm, the dimensional fit between the first plastic 22 and the electrode group 1 is unreasonable. When the electrode group 1 is inserted into the shell, the insulating film 11 will be scratched and the shell 3 will be damaged, and the heat-sealed connection between the insulating film 11 and the first plastic 22 will fall off after liquid injection, affecting the insulation performance of the cell.

[0065] Refer to Figure 2, in some embodiments, the length direction of the cover body 21 is parallel to the height direction of the electrode group 1, and the cover body 21 is disposed at the end of the electrode group 1. That is to say, the battery is designed with positive and negative electrode tabs on both sides.

[0066] In this embodiment, there are two cover bodies 21, and the two cover bodies 21 are respectively disposed at both ends of the electrode group 1, and the sizes of the two cover bodies 21 are equal.

[0067] In this way, the cover bodies 21 are symmetrically disposed at the ends of the electrode group 1, which can facilitate the assembly of the cover assembly 2 to the electrode group 1, improve the structural strength at both ends of the electrode group 1, and improve the dimensional fit of the electrode group 1, the first plastic 22, and the cover body 21, reduce the difficulty of inserting the electrode group 1 into the case, avoid assembly interference between the electrode group 1 and the case 3 or the first plastic 22 during the process of inserting the electrode group 1 into the case, improve the structural integrity of the electrode group 1. After the electrolyte is injected into the battery cell, the electrode group 1 expands and generates pressure on the first plastic 22 and the cover body 21 disposed at both ends of the electrode group 1. Since the first plastic 22 and the cover body 21 have certain structural strength, they can disperse the pressure generated by the electrode group 1 and avoid being pulled at the connection between the electrode group 1 and the first plastic 22, ensure the insulation performance of the first plastic 22, and improve the assembly yield and safety performance of the battery cell.

[0068] It can be understood that the setting position of the cover body 21 can be adjusted according to actual needs. In this embodiment, the design of positive and negative electrode tabs on both sides is adopted to adapt to the structure of the long battery cell and effectively utilize the space at both ends of the electrode group 1, which will not be elaborated here.

[0069] Refer to Figure 2 , in some embodiments, along the height direction of the cover body 21, the projection of the first plastic 22 is located inside the projection of the cover body 21, and the first plastic 22 is provided with a boss 221. Along the height direction of the first plastic 22, the projection of the boss 221 is located inside the projection of the first plastic 22.

[0070] In this embodiment, there are two bosses 221, and the two bosses 221 are respectively disposed at both ends of the first plastic 22. The cover body 21 is provided with a terminal post 211, and one end of the terminal post 211 facing the electrode group 1 is located between the two bosses 221, so as to facilitate the fixed connection between the terminal post 211 and the electrode tab by welding.

[0071] In this way, the cover plate body 21 can completely cover the first plastic 22. During the assembly process, the cover plate body 21 can provide lateral and longitudinal support for the first plastic 22, preventing the first plastic 22 from deforming during the process of being inserted into the housing, facilitating the proper assembly of the first plastic 22, improving the assembly yield. The boss 221 can enhance the structural strength of the region at the end of the electrode group 1 where no tab is provided, and press and support the end of the electrode group 1, preventing the electrode group 1 from shifting inside the housing 3. Moreover, the boss 221 does not extend beyond the edge of the first plastic 22 and is not likely to interfere with other structures during assembly, making the dimensional fit of the electrode group 1, the first plastic 22, and the cover plate body 21 more reasonable during the insertion of the electrode group 1 into the housing and reducing the difficulty of housing insertion.

[0072] It can be understood that the setting position and quantity of the boss 221 can be adjusted according to the design requirements of the battery, and will not be listed in detail here.

[0073] Refer to Figure 1 , in some embodiments, the battery further includes an insulating film 11 and a housing 3. The insulating film 11 is wrapped around the electrode group 1 and is disposed between the housing 3 and the electrode group 1. The position of the insulating film 11 corresponding to the end of the electrode group 1 is connected to the first plastic 22.

[0074] In this embodiment, the position of the insulating film 11 corresponding to the end of the electrode group 1 is fixedly connected to the boss 221 of the first plastic 22 by hot melting, and the cover plate body 21 and the housing 3 are hermetically fixedly connected by welding, so that the electrode group 1 is located in the closed space formed by the housing 3 and the cover plate body 21.

[0075] In this way, by restricting the difference between the height L1 of the electrode group 1 and the length L2 of the first plastic 22, and the difference between the width W1 of the electrode group 1 and the width W2 of the first plastic 22, the dimensions of the electrode group 1 and the first plastic 22 are adapted to each other, preventing stress concentration or affecting housing insertion due to an excessive dimensional difference between the electrode group 1 and the first plastic 22. When the electrode group 1 expands due to electrolyte injection into the battery cell, the connection between the electrode group 1 and the first plastic 22 has sufficient structural strength, and the cover plate body 21 can provide stable support for the first plastic 22, making it difficult for the hot-melt connection between the position of the insulating film 11 corresponding to the end of the electrode group 1 and the first plastic 22 to be pulled, reducing the risk of the insulating film 11 falling off and breaking, ensuring the insulation performance of the first plastic 22 and the insulating film 11, and improving the assembly yield and safety performance of the battery cell.

[0076] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A battery, characterized in that, Comprising: A pole group (1), the pole group (1) being connected with pole tabs; A cover plate assembly (2), the cover plate assembly (2) including a pole post (211), a cover plate body (21) and a first plastic (22), the pole post (211) being electrically connected to the pole tab, the first plastic (22) being disposed on a side of the cover plate body (21) facing the pole group (1); The width of the pole group (1) is W1, the width of the first plastic (22) is W2, the width of the cover plate body (21) is W3, and W1≥W2, W3≥W2 are satisfied.

2. The battery according to claim 1, characterized in that, 12.5mm≤W1≤49mm; and / or, the height of the pole group (1) is L1, and 70mm≤L1≤210mm is satisfied.

3. The battery according to claim 1, characterized in that, The height of the pole group (1) is L1, and 4.2≤L1 / W1≤5.6 is satisfied.

4. The battery according to claim 1, characterized in that, 0mm≤W1 - W2≤3mm, the height of the pole group (1) is L1, the length of the first plastic (22) is L2, and -1mm≤L1 - L2≤5mm is satisfied.

5. The battery according to claim 1, characterized in that, The length of the first plastic (22) is L2, the length of the cover plate body (21) is L3, and L3>L2 is satisfied.

6. The battery according to claim 5, characterized in that 3.5mm≤L3 - L2≤7mm.

7. The battery according to claim 6, characterized in that, 3mm≤W3 - W2≤7mm.

8. The battery according to any one of claims 1-7, characterized in that, The length direction of the cover plate body (21) is parallel to the height direction of the pole group (1), and the cover plate body (21) is disposed at an end of the pole group (1).

9. The battery according to any one of claims 1-7, characterized in that, Along the height direction of the cover plate body (21), the projection of the first plastic (22) is located inside the projection of the cover plate body (21); and / or, the first plastic (22) is provided with a boss (221), and along the height direction of the first plastic (22), the projection of the boss (221) is located inside the projection of the first plastic (22).

10. The battery according to any one of claims 1-7, characterized in that, The battery further includes an insulating film (11) and a housing (3), the insulating film (11) being coated on the pole group (1) and disposed between the housing (3) and the pole group (1), and a position of the insulating film (11) corresponding to the end of the pole group (1) being connected to the first plastic (22).

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