Battery cell cover plate assembly, battery cell and battery pack

Abstract

The invention relates to the technical field of batteries, and discloses a battery cell cover plate assembly, a battery cell and a battery pack. The battery cell cover plate assembly comprises a cover plate, a riveting block and a pole. The cover plate is provided with an assembly hole; the riveting block is provided with a pole mounting hole; the pole comprises a pole bottom plate and a pole body, the pole bottom plate and the riveting block are arranged on the two opposite sides of the cover plate respectively, and the pole body sequentially penetrates through the assembling hole and the pole mounting hole and is riveted with the riveting block; the area of the weldable area of the riveting block and the area of the pole bottom plate meet preset conditions. According to the invention, the ratio of the area S of the weldable area of the riveting block to the area S1 of the pole bottom plate is controlled within the range of 1.05-1.5. According to the invention, enough welding area between the riveting block and the busbar can be ensured, overhigh local overcurrent temperature is avoided, the safety risk of thermal runaway of the battery is reduced, meanwhile, the riveting block occupies a reasonable space on the cover plate, the arrangement of an explosion-proof valve is not influenced, and the safety of the battery is ensured.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a battery cover assembly, a battery cell and a battery pack. Background Art

[0002] In recent years, with the rapid development of the new energy vehicle market and increasing consumer demand for longer driving range and faster charging speeds, the demand for fast-charging and high-rate batteries has increased significantly. These high-performance batteries require the ability to support higher currents to meet the demands of fast charging and high power output. Blade batteries, with their high energy density, long life, and safety, have been widely used in electric vehicles.

[0003] The blade cell's cover plate adopts a slender structural design, which not only helps improve space utilization but also enhances the overall mechanical strength of the battery. However, to accommodate this cover plate structure, the rivet blocks and poles must also be designed to be narrow and long. In traditional square cells, the rivet blocks and busbars are usually welded using circular or runway-shaped welds to ensure sufficient welding area and good conductivity. However, on the narrow and long cover plate of the blade cell, due to space limitations, this large-scale weld shape cannot be achieved.

[0004] Due to the narrow and long design of the blade cell cover, the weld area between the rivet block and the busbar is significantly insufficient. This can lead to localized overcurrent bottlenecks, causing the rivet block to overheat when high current flows through it, posing a certain safety risk of thermal runaway. Furthermore, the insufficient weld area reduces connection reliability, affecting the overall performance and lifespan of the battery. Summary of the Invention

[0005] In view of this, the present invention provides a battery cover assembly, a battery cell and a battery pack to solve the problem of excessive temperature of the riveted block when a large current passes therethrough and reduced connection reliability caused by the obviously insufficient welding area between the riveted block and the busbar.

[0006] In a first aspect, the present invention provides a battery cell cover assembly, comprising a cover, a rivet block, and a terminal. The cover is provided with an assembly hole; the rivet block is provided with a terminal mounting hole; the terminal comprises a terminal base plate and a terminal body, the terminal base plate and the rivet block being respectively provided on opposite sides of the cover, the terminal body passing through the assembly hole and the terminal mounting hole in sequence and being riveted to the rivet block; the area of ​​the weldable area of ​​the rivet block and the area of ​​the terminal base plate satisfy the following requirements:

[0007]

[0008] in,

[0009] S is the area of ​​the weldable area of ​​the riveting block, in mm 2 ,

[0010] S1 is the area of ​​the pole bottom plate, in mm 2 ,

[0011] L1 is the length of the pole bottom plate along the X direction, in mm.

[0012] L2 is the distance from the edge of the riveted pole body to the first end of the riveted block along the X direction, in mm.

[0013] L3 is the distance from the edge of the riveted pole body to the second end of the riveted block along the X direction, in mm.

[0014] W1 is the width of the pole bottom plate along the Y direction, in mm.

[0015] W is the width of the riveting block along the Y direction, in mm.

[0016] Beneficial effect: The present invention controls the ratio of the area S of the weldable area of ​​the riveted block to the area S1 of the pole bottom plate within the range of 1.05 to 1.5. If the value is too small, lower than 1.05, the riveted block is too small, and the riveted block does not have enough weldable area, resulting in a smaller welding area between the riveted block and the busbar, which in turn causes the local temperature to rise, resulting in a safety risk of thermal runaway of the battery; if the ratio is too large, greater than 1.5, the riveted block is too large, causing the riveted block to occupy too much space on the cover plate, which in turn causes insufficient space for the explosion-proof valve of the battery cell, forcing the explosion-proof valve area to be reduced, causing a safety hazard. Therefore, The value is controlled within the range of 1.05 to 1.5, which can ensure that there is sufficient welding area between the riveted block and the busbar, avoid excessive local overcurrent temperature, and reduce the safety risk of battery thermal runaway. At the same time, the riveted block occupies a reasonable space on the cover plate, does not affect the layout of the explosion-proof valve, and ensures the safety of the battery.

[0017] In an optional embodiment, the size of the riveting block further satisfies:

[0018]

[0019] Wherein, L is the total length of the riveting block along the X direction, in mm.

[0020] In an optional embodiment, the size of the riveting block further satisfies:

[0021]

[0022] In an optional embodiment, the following conditions are also met:

[0023] L2≥2.5mm,

[0024] L3≥2.5mm.

[0025] In an optional embodiment, the dimension between the riveting block and the cover plate further satisfies:

[0026]

[0027] Wherein, L is the total length of the cover along the X direction, in mm.

[0028] In an optional embodiment, the dimension between the riveting block and the cover plate further satisfies:

[0029]

[0030] Wherein, W0 is the total width of the cover along the Y direction, in mm.

[0031] In an optional embodiment, a first insulating member is further included, and the riveting block and the cover plate are insulated and connected via the first insulating member;

[0032] Along the Y direction, the minimum margin between the edge of the riveting block and the cover plate satisfies:

[0033]

[0034] 0.6mm≤T≤1.0mm,

[0035] Wherein, T is the wall thickness of the first insulating member, in mm.

[0036] In an optional embodiment, along the X direction, the minimum margin from the edge of the first insulating member to the cover plate is L4, L4 ≥ 2.0 mm; the battery cell cover plate assembly also includes an explosion-proof valve, the cover plate is provided with an explosion-proof valve mounting hole, the explosion-proof valve is arranged in the explosion-proof valve mounting hole, and along the X direction, the minimum margin from the edge of the explosion-proof valve to the cover plate is L5, L5 ≥ 2.0 mm.

[0037] In the second aspect, the present invention also provides a battery cell, comprising a shell, a pole group and the battery cell cover assembly in the above technical solution, the shell having a accommodating cavity and an opening connected to the accommodating cavity; the pole group is arranged in the accommodating cavity of the shell; the battery cell cover assembly is arranged in the opening of the shell to encapsulate the pole group in the shell.

[0038] Beneficial Effects: The cell cover assembly is applied to the battery cell to seal the opening of the cell housing, sealing and protecting the internal components of the battery, preventing chemical leakage and the impact of the external environment on the battery. The poles of the cell cover assembly provide a path for the flow of current in and out, ensuring the current conduction during the battery cell's charging and discharging process. The cell cover assembly not only serves as an electrical connection for the battery cell, but also enhances the overall structural stability of the battery cell. It is an important component of the battery cell, ensuring the durability and safety of the battery cell during use.

[0039] Because the battery cell includes a battery cell cover plate assembly and has all the technical effects of the battery cell cover plate assembly, it will not be repeated here.

[0040] In a third aspect, the present invention further provides a battery pack comprising a plurality of battery cells according to the above technical solution, wherein the riveted blocks of adjacent battery cells are welded via a busbar.

[0041] Beneficial effects: Since the battery pack includes battery cells, it has all the technical effects of battery cells and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 An exploded view of a battery cell cover assembly according to an embodiment of the present invention;

[0044] Figure 2 for Figure 1 The front view of the cell cover assembly after assembly is shown;

[0045] Figure 3 for Figure 1 A top view of the cell cover assembly after assembly is shown;

[0046] Figure 4 for Figure 1 A bottom view of the cell cover assembly after assembly is shown;

[0047] Figure 5 For the Figure 3 Cross-sectional view at AA in the middle;

[0048] Figure 6 A schematic diagram of points for flatness measurement;

[0049] Figure 7 for the reason Figure 1 The overall structural diagram of the battery cell composed of the battery cell cover assembly shown;

[0050] Figure 8 for Figure 7 Exploded view of the external insulation film and insulation patch of the battery cell at the center cell cover assembly;

[0051] Figure 9 This is a top view of the battery cover assembly after assembly in the prior art;

[0052] Figure 10 for Figure 9 A partial enlarged view of point E in the middle;

[0053] Figure 11 For the Figure 9 Cross-sectional view at FF;

[0054] Figure 12 for Figure 11 A partial enlarged view of point D in the middle.

[0055] Description of reference numerals:

[0056] 1. Cover plate; 101. Assembly hole; 102. Explosion-proof valve mounting hole; 2. Rivet block; 201. Pole mounting hole; 3. Pole; 301. Pole base plate; 302. Pole body; 4. First insulating member; 5. Second insulating member; 6. Sealing ring; 7. Explosion-proof valve; 8. Explosion-proof valve patch; 9. External insulating film of the battery cell; 10. Insulation patch. DETAILED DESCRIPTION

[0057] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0058] In traditional square cells, circular or runway-shaped welds are usually used between the rivet block and the busbar to ensure sufficient welding area and good conductivity. However, for blade cells, due to the narrow and long design limitations of the blade cell cover 1, the welding area between the rivet block and the busbar is obviously insufficient, and this large-sized weld shape cannot be achieved. This will lead to the emergence of local overcurrent bottlenecks, causing the rivet block to overheat when large currents pass through, posing a certain thermal runaway safety risk. In addition, insufficient welding area will also reduce the reliability of the connection, affecting the overall performance and service life of the battery.

[0059] In order to solve the problem of insufficient welding area of ​​blade cells due to the structural limitations of the rivet block, the weld mark shape of the rivet block and the busbar can be designed as a long strip, which can increase the welding area of ​​the rivet block and the busbar. However, this solution requires increasing the length and width of the rivet block, which will bring the following technical problems:

[0060] 1. The riveted span is too large, which takes up too much space on the cover plate, resulting in no space for the explosion-proof valve to be arranged;

[0061] 2. The riveting block is long. After being riveted to the pole, the two ends of the riveting block are seriously warped. Figure 11 and Figure 12 , resulting in poor flatness, affecting the welding of battery cells and chips, and causing problems such as cold soldering.

[0062] Therefore, the present invention aims to solve the above-mentioned technical problems, so that the riveted block of the blade battery cell cover plate assembly has sufficient welding area to meet the demand for passing current, and provides reasonable size and size relationship settings for the riveted block, pole and cover plate, so as to simultaneously solve the problems of the flatness of the riveted block after riveting and the spatial arrangement of the explosion-proof valve.

[0063] The following combination Figures 1 to 8 , describing embodiments of the present invention.

[0064] According to an embodiment of the present invention, in a first aspect, a cell cover assembly is provided, comprising a cover 1, a rivet block 2, and a pole 3. The cover 1 is provided with an assembly hole 101; the rivet block 2 is provided with a pole mounting hole 201; the pole 3 comprises a pole base plate 301 and a pole body 302, the pole base plate 301 and the rivet block 2 being respectively provided on opposite sides of the cover 1, the pole body 302 passing through the assembly hole 101 and the pole mounting hole 201 in sequence and being riveted to the rivet block 2; the area of ​​the weldable area of ​​the rivet block 2 and the area of ​​the pole base plate 301 satisfy the following conditions:

[0065]

[0066] in,

[0067] S is the area of ​​the weldable area of ​​the riveting block 2, in mm 2 ,

[0068] S1 is the area of ​​the pole bottom plate 301, in mm 2 ,

[0069] L1 is the length of the pole bottom plate 301 along the X direction, in mm.

[0070] L2 is the distance from the edge of the riveted pole body 302 to the first end of the riveted block 2 along the X direction, in mm.

[0071] L3 is the distance from the edge of the riveted pole body 302 to the second end of the riveted block 2 along the X direction, in mm.

[0072] W1 is the width of the pole bottom plate 301 along the Y direction, in mm.

[0073] W is the width of the riveting block 2 along the Y direction, in mm.

[0074] Specifically, the pole bottom plate 301 is used to be welded to the tab of the battery cell to conduct the current inside the battery cell to the pole 3. The riveting block 2 is used to be welded to the busbar to conduct the current to the outside of the battery cell.

[0075] Reference Figure 3 , where the direction indicated by X represents the length direction of the cover plate 1, which is also the length direction of the riveting block 2 and the pole bottom plate 301; where the direction indicated by Y represents the width direction of the cover plate 1, which is also the width direction of the riveting block 2 and the pole bottom plate 301.

[0076] Since the rivet block 2 and the busbar are typically welded in the area on both sides of the pole 3, the total length of the weldable area of ​​the rivet block 2 is the sum of the distance L2 from the first end of the rivet block 2 to the first edge of the pole 3 adjacent thereto and the distance L3 from the second end of the rivet block 2 to the second edge of the pole 3 adjacent thereto. The total width of the weldable area of ​​the rivet block 2 is the width of the rivet block 2. Therefore, the value (L2 + L3) × W is the weldable area S of the rivet block 2 and the busbar.

[0077] The product of the length L1 and the width W1 of the pole bottom plate 301 is the area S1 of the pole bottom plate 301 , which is also the weldable area of ​​the pole bottom plate 301 .

[0078] During the entire use of the battery cell, the current passing through the inside of the cover plate 1 and the connections between the cover plate 1 and the inside and outside is the same. The rivet block 2 is connected to the external bus, and the pole bottom plate 301 is connected to the internal pole ear. Since the same current passes through the two places, theoretically the area required for the current to pass is also equal. Based on the fact that the thickness of the bus is usually larger than the thickness of the pole ear, the corresponding welded area on the upper surface of the rivet block 2 and the bus needs to be larger than the effective area. Compared with the welding of the pole bottom plate 301 and the pole ear, the rivet block 2 requires more weldable area. Therefore, the ratio of the area S of the weldable area of ​​the rivet block 2 to the area S1 of the pole bottom plate 301 is controlled within the above reasonable range to ensure that the rivet block 2 has sufficient weldable area.

[0079] The present invention controls the ratio of the area S of the weldable area of ​​the rivet block 2 to the area S1 of the terminal base plate 301 within a range of 1.05 to 1.5. If this ratio is too small, below 1.05, the rivet block 2 is too small and lacks sufficient weldable area, resulting in a smaller weld area between the rivet block 2 and the busbar, which in turn causes localized temperature increases and creates a safety risk of thermal runaway in the battery. If this ratio is too large, greater than 1.5, the rivet block 2 is too large, causing it to occupy too much space on the cover plate 1, resulting in insufficient space for the battery cell's explosion-proof valve 7, forcing the area of ​​the explosion-proof valve 7 to be reduced, creating a safety hazard.

[0080] Therefore, The value is controlled within the range of 1.05 to 1.5, which can ensure that there is sufficient welding area between the riveted block 2 and the busbar, avoid excessive local overcurrent temperature, and reduce the safety risk of thermal runaway of the battery. At the same time, the riveted block 2 occupies a reasonable space on the cover plate 1, does not affect the arrangement of the explosion-proof valve 7, and ensures the safety of the battery.

[0081] In some embodiments, the dimensions of the rivet block 2 also satisfy:

[0082]

[0083] Wherein, L is the total length of the riveting block 2 along the X direction, in mm.

[0084] In this embodiment, the size of the riveted block 2 is further optimized and limited, and the ratio of the total length L of the riveted block 2 to the width of the riveted block 2 is controlled within the range of 1.5 to 6.5. If the ratio is too small, less than 1.5, that is, the length of the riveted block 2 is relatively small, and the width of the riveted block 2 is affected by the size of the cover plate 1, under the limited size of the cover plate 1, the weldable area of ​​the riveted block 2 will be significantly reduced; if the ratio is too large, greater than 6.5, that is, the length of the riveted block 2 is relatively large, which will cause the riveted block 2 to warp and deform at both ends after being riveted to the pole 3 due to uneven riveting force, such as Figure 9 and Figure 10 As shown, the flatness of the riveting block 2 deteriorates, thereby affecting the welding quality between the riveting block 2 and the busbar.

[0085] Therefore, controlling the ratio of the total length L of the riveting block 2 to the width of the riveting block 2 within the range of 1.5 to 6.5 can ensure that the riveting block 2 has sufficient welding area and, at the same time, can ensure that the riveting block 2 has good flatness after riveting.

[0086] Specifically, flatness, as a geometric tolerance indicator, is used to assess the degree of deviation between an actual surface and an ideal plane. Simply put, it describes the flatness of a surface. A smaller flatness value indicates that the surface is closer to an ideal plane, meaning it is flatter. The embodiments provided by the present invention can ensure that the flatness of the riveted block 2 after riveting is less than or equal to 0.25 mm, meeting the flatness requirements of the battery cell for the riveted block 2.

[0087] In some embodiments, the dimensions of the rivet block 2 also satisfy:

[0088]

[0089] Taking into account the two situations of the pole 3 being arranged centrally or eccentrically relative to the riveted block 2, in order to further ensure that the riveted block 2 has sufficient weldable area, in this embodiment, the distance from the edge of the riveted pole body 302 to the end of the riveted block 2 is optimized and limited, and the ratio of the distance L2 from the edge of the riveted pole body 302 to the first end of the riveted block 2 to the width W of the riveted block 2 is controlled within the range of 0.5 to 3, and the ratio of the distance L3 from the edge of the riveted pole body 302 to the second end of the riveted block 2 to the width W of the riveted block 2 is controlled within the range of 0.5 to 3. If If the value is too small, less than 0.5, the edge of the riveted block 2 will be deformed outward after riveting. Figure 9 and Figure 10 As shown in the shaded part, it affects the appearance of the riveting block 2 and the visual positioning of the busbar during welding, thus causing the welding mark to deviate; if If the value is too large, the end of the rivet block 2 farther from the pole 3 will be easily warped and deformed, resulting in poor flatness of the rivet block 2 and problems such as cold welding after the rivet block 2 and the busbar are welded. The effect of a ratio that is too large or too small on the riveting block 2 is the same as above.

[0090] Therefore, through The value and The value of can be reasonably limited, which can not only ensure that the riveted block 2 has sufficient weldable area, but also ensure that the riveted block 2 after welding has a good appearance and good flatness, thereby ensuring the welding quality of the riveted block 2 and the busbar.

[0091] It can be understood that when the pole 3 is arranged centrally relative to the rivet block 2 , L2 = L3 .

[0092] In some embodiments, the following conditions are also met:

[0093] L2≥2.5mm,

[0094] L3≥2.5mm.

[0095] In this embodiment, the specific value ranges of the distance L2 from the edge of the riveted pole body 302 to the first end of the riveted block 2 and the distance L3 from the edge of the riveted pole body 302 to the second end of the riveted block 2 are further limited. It is required that the values ​​of L2 and L3 are both not less than 2.5 mm. Otherwise, it is easy to cause outward expansion deformation at both ends of the riveted block 2 after riveting, affecting the appearance.

[0096] In some embodiments, the dimensions between the riveting block 2 and the cover plate 1 also satisfy:

[0097]

[0098] Wherein, L is the total length of the cover plate 1 along the X direction, in mm.

[0099] In this embodiment, the dimensions of the rivet block 2 and the cover plate 1 are further limited, with the ratio of the length L of the rivet block 2 to the length L0 of the cover plate 1 being controlled within a range of 20% to 55%. If this ratio is too small, below 20%, the weldable area of ​​the rivet block 2 will be reduced. If it is too large, above 55%, the rivet block 2 will occupy a large portion of the cover plate 1. Since the battery cell cover plate assembly also includes an explosion-proof valve 7 and a liquid injection hole, this will affect the layout of the explosion-proof valve 7 and the liquid injection hole on the cover plate 1.

[0100] In some embodiments, the dimensions between the riveting block 2 and the cover plate 1 also satisfy:

[0101]

[0102] Wherein, W0 is the total width of the cover plate 1 along the Y direction, in mm.

[0103] In this embodiment, the dimensions of the rivet block 2 and the cover plate 1 are further limited, with the ratio of the width W of the rivet block 2 to the width W0 of the cover plate 1 being controlled within a range of 40% to 80%. If this ratio is too small, below 40%, the weldable area of ​​the rivet block 2 will be reduced. If it is too large, above 80%, the minimum margin between the edge of the rivet block 2 and the cover plate 1 along the Y direction will be too small. In other words, the rivet block 2 will occupy too much space in the width direction of the cover plate 1, thus affecting the flange wrapping of the outer insulating film 9 of the battery cell on the cover plate 1 and the application of the insulating patch 10.

[0104] In some embodiments, the dimensions between the riveting block 2 and the cover plate 1 further limit the range of the dimensions of the riveting block 2 and the cover plate 1 on the basis of satisfying the relationship in the above embodiments.

[0105] Specifically, the length L of the riveting block 2 satisfies: 15mm≤L≤75mm, and the width W of the riveting block 2 satisfies: 5mm≤W≤20mm; the length L0 of the cover plate 1 satisfies: 75mm≤L0≤230mm, and the width W0 of the cover plate 1 satisfies: 12mm≤W0≤28mm.

[0106] Specifically, the length L of the rivet block 2 is within the range of 15 mm to 75 mm, including 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm and 75 mm.

[0107] The width W of the rivet block 2 is within the range of 5 mm to 20 mm, including 5 mm, 8 mm, 10 mm, 12 mm, 15 mm, 18 mm and 20 mm.

[0108] The length L0 of the cover plate 1 is in the range of 75 mm to 230 mm, including 75 mm, 80 mm, 85 mm, 90 mm, 95 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm, 160 mm, 170 mm, 180 mm, 190 mm, 200 mm, 210 mm, 220 mm and 230 mm.

[0109] The width W0 of the cover plate 1 is within the range of 12 mm to 28 mm, including 12 mm, 15 mm, 18 mm, 20 mm, 22 mm, 25 mm and 28 mm.

[0110] In some embodiments, a first insulating member 4 is further included, and the riveting block 2 and the cover plate 1 are insulated and connected via the first insulating member 4;

[0111] Along the Y direction, the minimum margin between the edge of the riveting block 2 and the cover plate 1 satisfies:

[0112]

[0113] 0.6mm≤T≤1.0mm,

[0114] Wherein, T is the wall thickness of the first insulating member 4 , in mm.

[0115] Specifically, if Figure 8 As shown, the outside of the battery cell will be wrapped with an external insulating film 9 to ensure the insulation of the battery cell shell. When the external insulating film 9 is wrapped on the battery cell cover assembly, there will be a flange, which is attached to the battery cell cover assembly. The flange of the external insulating film 9 on the battery cell cover assembly can play an insulating protection role at the corner where the battery cell cover assembly and the battery cell shell are welded. Then the insulating patch 10 is attached to the outside of the cover 1, and the insulating patch 10 presses the flange of the external insulating film 9 of the battery cell to ensure the insulation of the outside of the cover 1.

[0116] In order to ensure the overall insulation performance of the battery cell, in this embodiment, the size of the riveted block 2 is further limited. In the above relationship, The value is the minimum margin from the edge of the rivet block 2 to the cover plate 1 along the Y direction, that is, the margin from the edge of one side of the rivet block 2 to the edge of the cover plate 1 on that side along the Y direction. The difference between this margin and the wall thickness of the first insulating member 4 should be no less than 2.5 mm. In this way, it can ensure that the external insulating film 9 of the battery cell has sufficient flange width when wrapping the battery cell to prevent the external insulating film 9 of the battery cell from warping. At the same time, it can ensure that the insulating patch 10 on the cover plate 1 has sufficient covering width to ensure the insulation safety performance of the battery cell.

[0117] The wall thickness T of the first insulating member 4 is in the range of 0.6 mm to 1.0 mm, including 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm and 1.0 mm.

[0118] In some embodiments, along the X direction, the minimum margin from the edge of the first insulating member 4 to the cover plate 1 is L4, L4 ≥ 2.0 mm; the battery cell cover plate assembly also includes an explosion-proof valve 7, the cover plate 1 is provided with an explosion-proof valve mounting hole 102, the explosion-proof valve 7 is arranged in the explosion-proof valve mounting hole 102, and along the X direction, the minimum margin from the edge of the explosion-proof valve 7 to the cover plate 1 is L5, L5 ≥ 2.0 mm.

[0119] Furthermore, the cell cover assembly also includes an explosion-proof valve patch 8, which is attached to the upper surface of the explosion-proof valve mounting hole 102 to protect the explosion-proof valve 7. The explosion-proof valve 7 is used to quickly explode and release pressure in the event of thermal runaway of the cell, thereby ensuring the safety of the battery.

[0120] In order to further ensure the overall insulation performance of the battery cell, in this embodiment, the minimum margin L4 from the edge of the first insulating member 4 to the cover plate 1 and the minimum margin L5 from the edge of the explosion-proof valve 7 to the cover plate 1 along the X direction are limited, both of which are not less than 2.0 mm. Otherwise, it is easy to cause the insulating patch 10 to partially warp due to insufficient coverage width, thereby posing certain safety hazards to the insulation performance of the battery cell.

[0121] In some embodiments, for the two layout modes of the pole 3 being a central arrangement and an eccentric arrangement relative to the riveted block 2 , it is further specified that the connection between the riveted block 2 and the pole 3 satisfies the following conditions:

[0122]

[0123] The above ratio is controlled within the range of 15% to 48%. If the ratio is too large, the riveted block 2 will be warped and deformed along the X direction after riveting, resulting in poor flatness of the riveted block 2. If the ratio is too small, that is, the distance from the edge of one side of the pole 3 to the end of the riveted block 2 on that side is small, the local strength of the riveted block 2 on that side will be insufficient, resulting in edge swelling and deformation of the riveted block 2 after riveting.

[0124] In some embodiments, the relationship between the dimensions of the pole base plate 301 and the dimensions of the cover plate 1 is further limited to satisfy:

[0125]

[0126] By controlling the ratio of the length L1 of the pole base plate 301 to the length L0 of the cover plate 1 within a range of 15% to 40%, and controlling the ratio of the width W1 of the pole base plate 301 to the width W0 of the cover plate 1 within a range of 50% to 90%, it is possible to make the spatial arrangement of the pole 3 on the cover plate 1 more reasonable while ensuring that the pole base plate 301 has a sufficient welding area, thereby facilitating the arrangement of structures such as the explosion-proof valve 7 and the liquid injection hole.

[0127] In order to verify the technical solutions and effects of the present invention, specific examples and comparative examples are provided below, and the following measurements are performed on each case:

[0128] 1. Flatness measurement requires that the flatness of the riveted block 2 after riveting is ≤0.25mm. That is, the flatness of the riveted block 2 after riveting is ≤0.25mm to be qualified. The flatness measurement method can adopt the test method known to those skilled in the art. As an example, after riveting, the present invention selects 8-12 points on the entire plane of the riveted block 2 within a range of 5mm inward along each edge of the riveted block 2, measures the height of each point, and calculates the maximum height difference from the highest point to the lowest point, which is the flatness. The measurement points are referenced to Figure 6 , where the shaded area indicated by G is the selected area of ​​the measurement points, and the points indicated by M are the measurement points, a total of 12.

[0129] 2. Temperature testing of the weld marks at the welds of riveted block 2 and busbar. The temperature rise test of a battery cell is an important experiment to evaluate the temperature changes of a battery during the charge and discharge process, primarily used to ensure battery safety and performance. The temperature rise test of a battery cell is conducted using test methods well known to those skilled in the art. As an example, the following is a detailed test method and steps:

[0130] (1) First, prepare the test environment. The test environment temperature is 25°C, and the ambient humidity is kept stable to prevent humidity changes from affecting the test results. Ensure that the test area is well ventilated to prevent heat accumulation or the accumulation of harmful gases. Use a constant current and constant voltage power supply to control the charge and discharge current and voltage, and use a thermocouple or temperature sensor as a tool for temperature measurement. Directly attach the thermocouple or temperature sensor to the measurement point to be tested. The measurement points of the present invention are selected on the surface of the busbar and the weld mark of the riveted block.

[0131] (2) The selected test cell should be charged and discharged to within 20% SOC and left to stand for about 1 hour to eliminate the residual heat during the pretreatment process.

[0132] (3) Set test parameters such as the charge and discharge current, temperature alarm threshold, etc. The charge and discharge current is usually based on the charge and discharge conditions used by the test cell, such as a step charge strategy, 2C, 3C, or higher. Set the cutoff voltage according to the system specifications of the cell (for example, lithium-ion batteries are usually 2.5-4.2V). It is also necessary to set a temperature alarm threshold, and automatically stop the test when it exceeds 70°C to prevent thermal runaway caused by overcharging, over-discharging, or overheating of the cell.

[0133] (4) Start the test, first charge the battery to 3.2V at a constant current, then let it stand for at least 30 minutes to stabilize the voltage, collect temperature data at this time, and then perform the discharge process to reduce the voltage to 2.0V. After the discharge is completed, let it stand for at least 30 minutes and collect temperature data again. The above charging and discharging process is considered a cycle, and usually at least 5 charge and discharge cycles are performed. Set the temperature data acquisition to record data every 10 to 30 seconds, and record the temperature change data over time in real time.

[0134] (5) Analyzing the test data, the temperature exceeds 65°C, which does not meet the requirements.

[0135] 3. Check the welding quality between the riveted block 2 and the busbar to see if there are any cold welds, i.e., loose welds, poor contact, or holes. Testing methods known to those skilled in the art can be used. For example, the following testing methods can be used:

[0136] Method 1: Visual inspection: Observe the solder joints with the naked eye or a magnifying glass to check for the following characteristics: surface roughness, cracks, or oxidation; shorts or bridges between solder joints; and insufficient contact area between the solder joint and the pad / pin. Advantages: Simple, low-cost, and quick to detect obvious defects. Disadvantages: Relying on operator experience, it cannot detect minor cold solder joints or internal defects (such as voids within BGA solder balls).

[0137] Method 2: Resistance Test: Use a multimeter or precision resistance tester to measure the resistance between solder joints. A normal solder joint should have very low resistance (microohms). If the resistance is significantly elevated (e.g., over 10 milliohms), it may indicate a poor solder joint. Advantages: Directly reflects conductivity and is suitable for single-point testing. Disadvantages: Requires contact with the test point, which may interfere with delicate solder joints.

[0138] Method 3: Destructive Testing—Tensile Testing—applies tension to the solder joint to test its mechanical strength. Weak solder joints tend to fall off easily. Advantages: Accurate results and quantifiable weld strength. Disadvantages: Destructive to the sample, suitable only for spot checks.

[0139] Here, method 1 is used to test the welding quality of each case.

[0140] 4. Quality inspection of the four sides of the riveted block 2. Specifically, check whether the four sides of the riveted block 2 are deformed outward.

[0141] The test results of the embodiment are shown in Table 1.

[0142] Table 1

[0143]

[0144] As can be seen from Table 1, in Examples 1 to 5, the values ​​of S / S1 are between 1.05 and 1.50, which meet the conditions defined in the present invention. The test results are as follows:

[0145] 1. Flatness measurement: the flatness of the riveted block 2 after riveting is ≤0.25mm, which meets the requirements;

[0146] 2. Temperature detection of the weld marks at riveted block 2 and busbars. The measured temperatures are all below 65°C, which meets the requirements.

[0147] 3. The welding quality between the riveting block 2 and the busbar is tested and there is no cold welding, which meets the requirements;

[0148] 4. Quality inspection of the four sides of the riveted block 2 shows that the riveted block 2 has no warping deformation or outward expansion deformation, which meets the requirements.

[0149] The comparative test results are shown in Table 2.

[0150] Table 2

[0151]

[0152] Table 2 shows that in Comparative Examples 1, 4, and 5, the S / S1 ratio is too small, all below 1.05. The weld temperatures at both the rivet block 2 and the busbar are above 65°C, which is too high and causes local overheating in the battery cell, failing to meet the required flatness. Furthermore, in Comparative Example 4, the end of the rivet block 2 along the X direction warped and deformed, and the flatness of the rivet block 2 exceeded 0.25 mm, failing to meet the flatness requirements of the battery cell.

[0153] In Comparative Examples 2 and 3, the S / S1 ratio was too high, both exceeding 1.5. The weld temperatures at the rivet block 2 and the busbar met the requirements, as did the flatness of the rivet block 2. However, the weldable area of ​​the rivet block 2 was too large, occupying a significant amount of space on the cover plate 1, making it impossible to install the explosion-proof valve 7. Furthermore, in Comparative Example 3, the edges of the rivet block 2 partially expanded and deformed, affecting its appearance, making the design unsuitable.

[0154] Combining Table 1 and Table 2, it can be clearly concluded that the present invention controls the ratio of the area S of the weldable area of ​​the rivet block 2 to the area S1 of the pole bottom plate 301 within the range of 1.05 to 1.50, which can ensure that the rivet block 2 has a sufficient weldable area, and the temperature of the weld mark at the rivet block 2 and the busbar is lower than 65°C, solving the problem of local overheating of the battery cell. At the same time, it ensures good welding quality between the rivet block 2 and the busbar, and the flatness of the rivet block 2 after riveting is good, less than or equal to 0.25 mm, and there is no warping or outward deformation on the four sides of the rivet block 2, and the appearance is good.

[0155] In some embodiments, a second insulating member 5 is further included. The first surface of the cover plate 1 and the riveted block 2 are insulated and connected via the first insulating member 4 , and the second surface of the cover plate 1 and the pole 3 are insulated and connected via the second insulating member 5 .

[0156] Specifically, in some embodiments, the first insulating member 4 and the second insulating member 5 are both plastic members. The first insulating member 4 and the second insulating member 5 are used to ensure insulation between the cover plate 1 and the rivet block 2, and between the cover plate 1 and the pole 3, thereby preventing short circuits or leakage in the battery cell and improving the safety and reliability of the battery cell.

[0157] In some embodiments, the battery cell cover plate assembly also includes a sealing ring 6, which is sleeved on the pole body 302, and at least part of the sealing ring 6 is arranged between the pole body 302 and the assembly hole 101 of the cover plate 1, and at least part of the sealing ring 6 is arranged between the pole base plate 301 and the cover plate 1. In this way, the sealing ring 6 can form a seal between the pole 3 and the cover plate 1 along the Z direction and the XY plane, thereby improving the sealing, reliability and safety of the battery cell.

[0158] According to an embodiment of the present invention, in a second aspect, a battery cell is further provided, comprising a shell, a pole group and the battery cell cover assembly of the above embodiment, wherein the shell has a accommodating cavity and an opening connected to the accommodating cavity; the pole group is arranged in the accommodating cavity of the shell; the battery cell cover assembly is arranged in the opening of the shell to encapsulate the pole group in the shell.

[0159] The cell cover assembly is applied to the battery cell to seal the opening of the cell housing, sealing and protecting the internal components of the battery, preventing chemical leakage and the impact of the external environment on the battery. The pole 3 of the cell cover assembly provides a path for current to flow in and out, ensuring current conduction during the battery cell's charging and discharging process. The cell cover assembly not only serves as an electrical connection for the battery cell but also enhances the overall structural stability of the battery cell. It is an important component of the battery cell, ensuring the durability and safety of the battery cell during use.

[0160] In some embodiments, the battery cell is a blade battery cell.

[0161] Because the battery cell includes a battery cell cover plate assembly and has all the technical effects of the battery cell cover plate assembly, it will not be repeated here.

[0162] According to an embodiment of the present invention, in a third aspect, a battery pack is further provided, comprising a plurality of battery cells according to the above embodiments, wherein the rivet blocks 2 of adjacent battery cells are welded via a busbar.

[0163] Because the battery pack includes battery cells and has all the technical effects of battery cells, they will not be described here.

[0164] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A battery cover assembly, characterized in that: include: A cover plate, wherein the cover plate is provided with an assembly hole; A riveting block, wherein the riveting block is provided with a pole mounting hole; A pole, comprising a pole bottom plate and a pole body, wherein the pole bottom plate and the rivet block are respectively arranged on opposite sides of the cover plate, and the pole body passes through the assembly hole and the pole mounting hole in sequence and is riveted to the rivet block; The area of ​​the weldable region of the riveting block and the area of ​​the pole bottom plate satisfy: in, S is the area of ​​the weldable area of ​​the riveting block, in mm 2 , S1 is the area of ​​the pole bottom plate, in mm 2 , L1 is the length of the pole bottom plate along the X direction, in mm. L2 is the distance from the edge of the riveted pole body to the first end of the riveted block along the X direction, in mm. L3 is the distance from the edge of the riveted pole body to the second end of the riveted block along the X direction, in mm. W1 is the width of the pole bottom plate along the Y direction, in mm. W is the width of the riveting block along the Y direction, in mm.

2. The battery cover assembly according to claim 1, characterized in that: The dimensions of the riveting block also meet the following requirements: Wherein, L is the total length of the riveting block along the X direction, in mm.

3. The battery cover assembly according to claim 1 or 2, characterized in that: The dimensions of the riveting block also meet the following requirements:

4. The battery cover assembly according to claim 1 or 2, characterized in that: Also meets: L2≥2.5mm, L3≥2.5mm.

5. The battery cover assembly according to claim 1 or 2, characterized in that: The dimensions between the riveting block and the cover plate also meet the following requirements: Wherein, L is the total length of the cover plate along the X direction, in mm.

6. The battery cover assembly according to claim 1 or 2, characterized in that: The dimensions between the riveting block and the cover plate also meet the following requirements: Wherein, W0 is the total width of the cover plate along the Y direction, in mm.

7. The battery cover assembly according to claim 1 or 2, characterized in that: It also includes a first insulating member, through which the riveting block and the cover plate are insulated and connected; Along the Y direction, the minimum margin between the edge of the riveting block and the cover plate satisfies: 0.6mm≤T≤1.0mm, Wherein, T is the wall thickness of the first insulating member, in mm.

8. The battery cover assembly according to claim 7, characterized in that: Along the X direction, the minimum margin between the edge of the first insulating member and the cover plate is L4, L4 ≥ 2.0 mm; The battery cover assembly also includes an explosion-proof valve. The cover is provided with an explosion-proof valve mounting hole. The explosion-proof valve is arranged in the explosion-proof valve mounting hole. Along the X direction, the minimum margin from the edge of the explosion-proof valve to the cover is L5, and L5 is ≥ 2.0 mm.

9. A battery cell, characterized in that: include: a housing, the housing comprising a receiving cavity and an opening communicating with the receiving cavity; a pole group, the pole group being arranged in the accommodating cavity of the shell; The battery cell cover plate assembly according to any one of claims 1 to 8, wherein the battery cell cover plate assembly is arranged at the opening of the shell, and the electrode group is encapsulated in the shell.

10. A battery pack, characterized in that: The invention comprises a plurality of battery cells according to claim 9, wherein the rivet blocks of adjacent battery cells are welded by a busbar.

Images