Cover plate assembly, battery and battery pack

Abstract

The embodiment of the application provides a cover plate assembly, a battery and a battery pack, and relates to the technical field of batteries. The cover plate assembly provided by the embodiment of the application comprises a cover plate and a pole, and an insulating piece is arranged between the pole and the cover plate. In a second direction, the ratio of the size of the first flange to the size of the pole is K1, the sum of the size of the first vertical section of the first flange of the cover plate in a third direction and the size of the first fastening section in the first direction is L1, the sum of the size of the second vertical section of the second flange of the cover plate in the third direction and the size of the second fastening section in the second direction is L2, and K1, L1 and L2 satisfy: 0.1<=K1x(L1 / L2)<=1.7. The cover plate assembly, the battery and the battery pack provided by the embodiment of the application improve the fixing strength of the first flange on the pole, so that the pole is not prone to displacement, thereby guaranteeing the insulation performance of the battery.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a cover plate assembly, a battery, and a battery pack. Background Technology

[0002] With the increasing need for fast charging in electric vehicles, high-voltage fast charging technology has become a key direction for industry development. To achieve high-voltage output, the battery pack uses multiple batteries connected in series.

[0003] In related technologies, the battery cover assembly includes a cover plate and terminals with different length and width dimensions. A sealing ring and insulating adhesive are provided between the cover plate and the terminals. The cover plate is fixed to the terminals by riveting.

[0004] However, the terminals are prone to displacement, leading to insulation failure and causing a short circuit in the battery. Summary of the Invention

[0005] This application provides a cover plate assembly, a battery, and a battery pack to solve the problem that the terminals are prone to displacement, leading to insulation failure and causing a short circuit in the battery.

[0006] In a first aspect, embodiments of this application provide a cover plate assembly, including:

[0007] A cover plate, wherein the cover plate is provided with mounting holes, two first flanges and two second flanges, the two first flanges are provided on opposite sides of the mounting holes in a first direction, and the two second flanges are provided on opposite sides of the mounting holes in a second direction, and the first flanges and the second flanges are located on the same side of the plane on which the top of the mounting holes are located;

[0008] The pole is fixed in the mounting hole by the first flange and the second flange. An insulating element is provided between the pole and the cover plate. The ratio of the size of the pole in the second direction to the size of the pole in the first direction is greater than or equal to 1.5 and less than or equal to 8.

[0009] The first flange includes a first vertical segment extending along a third direction and a first fastening segment extending along the first direction; the second flange includes a second vertical segment extending along the third direction and a second fastening segment extending along the second direction.

[0010] In the second direction, the ratio of the size of the first flange to the size of the pole post is K1;

[0011] The first direction, the second direction, and the third direction are perpendicular to each other;

[0012] The sum of the dimension of the first vertical segment in the third direction and the dimension of the first fastening segment in the first direction is L1, and the sum of the dimension of the second vertical segment in the third direction and the dimension of the second fastening segment in the second direction is L2;

[0013] K1, L1, and L2 satisfy the condition: 0.1 ≤ K1 × (L1 / L2) ≤ 1.7, where the units of L1 and L2 are both mm.

[0014] Secondly, embodiments of this application provide a battery, including a housing and the cover assembly described in the first aspect; the cover assembly is connected to the housing.

[0015] Thirdly, embodiments of this application provide a battery pack including a plurality of batteries as described in the second aspect.

[0016] This application provides a cover plate assembly, a battery, and a battery pack. If K1×(L1 / L2) is less than 0.1, the dimension of the first flange in the second direction may be too small, or the sum of the dimension of the first vertical segment of the first flange in the third direction and the dimension of the first fastening segment in the first direction may be too small. This reduces the fixing strength of the first flange to the terminal post, making the terminal post prone to displacement and easy to overlap with other metal parts, leading to insulation failure and causing a short circuit in the battery. If K1×(L1 / L2) is greater than 1.7, the dimension of the first flange in the second direction may be too large, and the sum of the dimension of the first vertical segment of the first flange in the third direction and the dimension of the first fastening segment in the first direction may be too large. This results in an excessively large area of ​​the first flange covering the surface of the terminal post, leading to poor heat dissipation and poor current carrying capacity of the terminal post. By setting K1×(L1 / L2) to be greater than or equal to 0.1 and less than or equal to 1.7, the fixing strength of the first flange to the terminal post can be improved, making the terminal post less prone to displacement, thereby ensuring the insulation performance of the battery. It can also reduce the area of ​​the first flange covering the surface of the terminal post, thereby improving the heat dissipation performance and current carrying capacity of the terminal post. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a battery provided in an embodiment of this application;

[0019] Figure 2 for Figure 1A cross-sectional view of the battery in the diagram;

[0020] Figure 3 for Figure 1 A schematic diagram of the cover plate assembly in the middle;

[0021] Figure 4 for Figure 3 A top view of the cover plate assembly;

[0022] Figure 5 for Figure 4 A cross-sectional view of section Y1-Y1 in the diagram;

[0023] Figure 6 for Figure 4 A cross-sectional view of section X1-X1 in the diagram;

[0024] Figure 7 for Figure 3 Enlarged diagram of point J in the diagram;

[0025] Figure 8 This is a partial schematic diagram of the cover plate assembly;

[0026] Figure 9 This is a schematic diagram of the pole structure provided in an embodiment of this application;

[0027] Figure 10 This is a cross-sectional schematic diagram of the pole provided in an embodiment of this application.

[0028] Explanation of reference numerals in the attached figures:

[0029] 100-Cover plate assembly; 10-Cover plate; 101-First flange; 1011-First vertical section; 1012-First fastening section; 1013-First rounded corner; 1014-First side; 1015-Second side; 102-Second flange; 1021-Second vertical section; 1022-Second fastening section; 1023-Second rounded corner; 103-Cover plate body; 104-Mounting hole; 105-Connecting section; 20-Pole post; 201-Pole post body; 202-First protrusion; 203-Second protrusion; 20a-First body; 20b-Second body; 30-Insulating component; 40-Sealing component; 200-Housing; 300-Battery cell. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0032] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "fixation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0033] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0034] In the above description, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0035] As mentioned in the background section, the terminals are prone to displacement, leading to insulation failure and causing a battery short circuit. Research has found that this problem occurs because the flange on the long side of the terminal is too small in the length direction of the battery, or the sum of the vertical segment of the flange in the height direction and the fastening segment in the width direction of the battery is too small. This results in insufficient fixing strength of the flange on the long side of the terminal to the terminal, making the terminal prone to displacement. The insulation component is prone to detachment or displacement, and the terminal is prone to overlapping with other metal components, leading to insulation failure and a battery short circuit.

[0036] To address the aforementioned issues, this application provides a cover plate assembly, a battery, and a battery pack. In the length direction of the battery, the ratio of the size of the flange on the long side of the terminal post to the size of the terminal post is K1. The sum of the vertical segment of the flange on the long side of the terminal post in the height direction and the size of the fastening segment in the width direction of the battery is L1. The sum of the vertical segment of the flange on the short side of the terminal post in the height direction and the size of the fastening segment in the length direction of the battery is L2. By limiting the relationship between K1, L1, and L2, the fixing strength of the first flange to the terminal post is improved, making it less prone to displacement of the terminal post, thereby ensuring the insulation performance of the battery.

[0037] The cover plate assembly, battery, and battery pack provided in this application will be described in detail below with reference to specific embodiments.

[0038] First, see Figure 1 Let the length direction of the battery be defined as the X direction, i.e., the second direction is the X direction; let the width direction of the battery be defined as the Y direction, i.e., the first direction is the Y direction; and let the thickness direction of the battery be defined as the Z direction, i.e., the third direction is the Z direction. The first, second, and third directions are perpendicular to each other.

[0039] Firstly, see [the following] Figure 1 and Figure 2 As shown, this application provides a cover plate assembly 100 applied to a battery. The battery includes a housing 200, a cell 300, and a cover plate assembly 100. The cover plate assembly 100 is connected to the housing 200, and the cover plate assembly 100 and the housing 200 form a cavity. The cell 300 is disposed in the cavity, which is filled with electrolyte.

[0040] Cell 300 is the component in the battery where electrochemical reactions occur; it is the smallest unit in the battery capable of charging or discharging.

[0041] Cell 300 is the basic unit in a battery, typically including a positive electrode, a negative electrode, and a separator. For example, a lithium-ion cell primarily operates by the intercalation and deintercalation of lithium ions between the positive and negative electrodes.

[0042] The battery cell 300 can be cylindrical or cuboid. In a cylindrical battery cell, the positive electrode, negative electrode, and separator are wound into a cylindrical shape. In a cuboid battery cell, the positive electrode, negative electrode, and separator are wound or stacked into a roughly cuboid shape.

[0043] The housing 200 is a component used to provide a receiving space to house the battery cell and other components and isolate them from the outside environment. The housing 200 includes a body with an opening at at least one end and a receiving cavity. The opening of the housing 200 can be closed by a cover plate 10 to seal and isolate the internal environment of the battery from the external environment.

[0044] The material of the casing 200 includes, but is not limited to, metal materials such as copper, iron, aluminum, stainless steel or aluminum alloy.

[0045] In one possible implementation, see Figure 3 and Figure 4 As shown, the cover assembly 100 includes a cover 10.

[0046] The length direction of the cover plate 10 is the same as the length direction of the battery, the width direction of the cover plate 10 is the same as the width direction of the battery, and the thickness direction of the cover plate 10 is the same as the thickness direction of the battery.

[0047] The cover plate 10 is a component that closes the opening of the housing 200 to isolate the internal environment of the battery from the external environment.

[0048] The material of the cover plate 10 includes, but is not limited to, metal materials such as copper, iron, aluminum, stainless steel or aluminum alloy.

[0049] The cover plate 10 has a dimension of L3 in the second direction. The cover plate 10 has a dimension of L4 in the first direction.

[0050] In some examples, L3 is greater than or equal to 120mm and less than or equal to 350mm. For example, the value of L3 can be 120mm, 150mm, 200mm, 250mm, 300mm, or 350mm, etc.

[0051] In some examples, L4 is greater than or equal to 20mm and less than or equal to 80mm. For example, the value of L4 can be 20mm, 30mm, 50mm, 55mm, 70mm, or 80mm, etc.

[0052] In some examples, the ratio of L3 to L4 is greater than or equal to 2.6 and less than or equal to 14. For example, the ratio of L3 to L4 can take values ​​of 2.6, 3, 6, 8, 9, 10, or 14. The units for both L3 and L4 are mm.

[0053] See Figure 4 , Figure 5 and Figure 6 As shown, the cover plate 10 is provided with mounting holes 104, two first flanges 101 and two second flanges 102.

[0054] The mounting hole 104 extends through the cover plate 10 in a third direction. The dimension of the mounting hole 104 in the second direction is larger than the dimension of the mounting hole 104 in the first direction.

[0055] The top of the mounting hole 104 is on the +Z side, and the bottom of the mounting hole 104 is on the -Z side.

[0056] In some examples, the cover plate 10 is provided with two mounting holes 104, which are spaced apart along the second direction.

[0057] Two first flanges 101 are provided on opposite sides of the mounting hole 104 in the first direction, and two second flanges 102 are provided on opposite sides of the mounting hole 104 in the second direction.

[0058] The first flange 101 and the second flange 102 are located on the same side of the plane containing the top of the mounting hole 104.

[0059] In some examples, the cover plate 10 includes a cover plate body 103, a first flange 101 and a second flange 102, and a mounting hole 104 penetrates the cover plate body 103 in a third direction. A first flange 101 is provided on each side of the mounting hole 104 in the first direction, and a second flange 102 is provided on each side of the mounting hole 104 in the second direction. The first flange 101 and the second flange 102 both protrude from the outer edge of the mounting hole 104 in the third direction, and both the first flange 101 and the second flange 102 are bent toward the center of the mounting hole 104.

[0060] Both the first flange 101 and the second flange 102 are bent.

[0061] In the third direction, both the first flange 101 and the second flange 102 are located on the side of the cover body 103 away from the battery cell 300. Both the first flange 101 and the second flange 102 are connected to the cover body 103.

[0062] In some examples, the first flange 101 includes a first vertical segment 1011 extending along a third direction and a first fastening segment 1012 extending along a first direction, the first vertical segment 1011 being connected to the first fastening segment 1012. The second flange 102 includes a second vertical segment 1021 extending along a third direction and a second fastening segment 1022 extending along a second direction, the second vertical segment 1021 being connected to the second fastening segment 1022.

[0063] The dimension of the first flange 101 in the second direction is m. m is greater than or equal to 15mm and less than or equal to 80mm. For example, the value of m can be 15mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm or 80mm, etc.

[0064] The dimension of the first vertical segment 1011 in the third direction is h1. h1 is greater than or equal to 1 mm and less than or equal to 3 mm. The value of h1 can be 1 mm, 1.1 mm, 1.5 mm, 2 mm or 3 mm, etc.

[0065] If h1 is less than 1 mm, the first flange 101 is too small in the third direction, causing the first fastening section 1012 to be unable to press against the pole post 20, and the first flange 101 to be unable to fix the pole post 20. If h1 is greater than 3 mm, the first flange 101 is too large in the third direction, causing the first flange 101 to easily interfere with the busbar. By ensuring that h1 is greater than or equal to 1 mm and less than or equal to 3 mm, the first fastening section 1012 can press against the pole post 20, the first flange 101 can fix the pole post 20, and interference with the busbar can be avoided.

[0066] The dimension of the first fastening section 1012 in the first direction is y1. y1 is greater than or equal to 1 mm and less than or equal to 3 mm. The value of y1 can be 1 mm, 1.1 mm, 1.5 mm, 2 mm or 3 mm, etc.

[0067] If y1 is less than 1 mm, the size of the portion of the first flange 101 covering the pole post 20 in the first direction is too small, resulting in insufficient fixing strength of the first flange 101 to the pole post 20. If y1 is greater than 3 mm, the size of the portion of the first flange 101 covering the pole post 20 in the first direction is too large, and the size of the pole post 20 in the first direction is too small, resulting in poor current-carrying capacity of the pole post 20. By ensuring that y1 is greater than or equal to 1 mm and less than or equal to 3 mm, the fixing strength of the first flange 101 to the pole post 20 can be improved, and the current-carrying capacity of the pole post 20 can also be improved.

[0068] The sum of h1 and y1 is L1.

[0069] The second vertical segment 1021 has a dimension h2 in the third direction. h2 is the same as h1.

[0070] The second fastening section 1022 has a dimension of y2 in the second direction. y2 is greater than or equal to 0.8 mm and less than or equal to 2 mm. The value of y2 can be 0.8 mm, 1 mm, 1.1 mm, 1.5 mm, or 2 mm, etc.

[0071] If y2 is less than 0.8 mm, the size of the portion of the second flange 102 covering the pole post 20 in the second direction is too small, resulting in insufficient fixing strength of the second flange 102 to the pole post 20. If y2 is greater than 2 mm, the size of the portion of the second flange 102 covering the pole post 20 in the second direction is too large, and the size of the pole post 20 in the second direction is too small, resulting in poor current-carrying capacity of the pole post 20. By ensuring that y2 is greater than or equal to 0.8 mm and less than or equal to 2 mm, the fixing strength of the second flange 102 to the pole post 20 can be improved, and the current-carrying capacity of the pole post 20 can also be improved.

[0072] The sum of h2 and y2 is L2.

[0073] The cover plate assembly 100 also includes a pole post 20. The length direction of the pole post 20 is the same as the length direction of the cover plate 10, that is, the length direction of both the pole post 20 and the cover plate 10 is the same as the second direction. The width direction of the pole post 20 is the same as the width direction of the cover plate 10, that is, the width direction of both the pole post 20 and the cover plate 10 is the same as the first direction.

[0074] The pole post 20 is larger in the second direction than in the first direction, and the pole post 20 is fixed in the mounting hole 104 by the first flange 101 and the second flange 102.

[0075] The terminal 20 is used to electrically connect the battery cell 300 located inside the housing 200 to external devices (adjacent batteries or other electrical equipment) located outside the housing 200.

[0076] The battery can discharge to external devices through the tabs of cell 300 and terminals 20. An external power source can charge the battery through terminals 20 and the tabs of cell 300.

[0077] The pole 20 can be directly electrically connected to the tab of the cell 300, or it can be electrically connected to the tab of the cell 300 through a metal adapter.

[0078] The materials of the pole 20 include, but are not limited to, copper, aluminum, aluminum alloy, or copper-aluminum alloy.

[0079] There are two pole posts 20. The two pole posts 20 are installed in two mounting holes 104.

[0080] In some examples, one of the two terminals 20 is the positive terminal and the other is the negative terminal. The positive terminal can be made of aluminum. The negative terminal can be made of a copper-aluminum alloy.

[0081] The shape of the pole post 20 is not specifically set, as long as the dimension of the pole post 20 in the second direction is greater than the dimension of the pole post 20 in the first direction.

[0082] In some examples, the pole post 20 is racetrack shaped, with the two long sides of the pole post 20 on both sides in the first direction being straight, and the two short sides of the pole post 20 on both sides in the second direction being arc-shaped.

[0083] The cover plate assembly 100 also includes an insulating element 30. The insulating element 30 is disposed in the gap between the pole post 20 and the cover plate 10. The insulating element 30 is used to prevent the pole post 20 from contacting the cover plate 10, thereby insulating the pole post 20 from the cover plate 10.

[0084] Specifically, insulating elements 30 are provided between the cover plate body 103 and the pole post 20, between the first flange 101 and the pole post 20, and between the second flange 102 and the pole post 20.

[0085] The insulating element 30 may be made of an insulating material. In some examples, the insulating element 30 may be made of plastic, rubber, or other insulating materials. The plastic may be polyethylene terephthalate (PET), polypropylene (PP), polycarbonate (PC), or polyvinyl chloride (PVC). The rubber may be fluororubber, nitrile rubber, or isobutylene rubber.

[0086] The dielectric strength of the insulating component 30 can be greater than or equal to 15kV / mm and less than or equal to 240kV / mm. This setting allows the insulating component 30 to achieve the insulation effect.

[0087] In some examples, the insulating element 30 may be made of a fluororubber sheet with a thickness of 1 mm.

[0088] In some examples, the first fastening section 1012 of the first flange 101 and the second fastening section 1022 of the second flange 102 both press against the insulating member 30.

[0089] The dimension of the pole post 20 in the second direction is p1. p1 is greater than or equal to 15mm and less than or equal to 80mm. For example, the value of p1 can be 15mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm or 80mm, etc.

[0090] The dimension of the pole post 20 in the first direction is p2. p2 is greater than or equal to 10 mm and less than or equal to 50 mm. For example, the value of p2 can be 10 mm, 15 mm, 20 mm, 30 mm, 40 mm or 50 mm, etc.

[0091] The ratio of p1 to p2 is greater than or equal to 1.5 and less than or equal to 8. For example, the ratio of p1 to p2 can take values ​​of 1.5, 1.6, 2, 3, 5, 6, or 8, etc. The units for both p1 and p2 are mm.

[0092] The ratio K1 is the ratio of m to p1. The units of m and p1 are both mm. K1 is greater than or equal to 0.2 and less than or equal to 1. For example, the value of K1 can be 0.2, 0.25, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.95 or 1, etc.

[0093] If K1 is less than 0.2, the first flange 101 will be too small in the second direction, reducing its fixing strength to the terminal 20. This makes the terminal 20 prone to displacement and overlap with other metal parts, preventing the insulating component 30 from providing insulation and causing insulation failure, resulting in a short circuit in the battery. If K1 is greater than 1, the first flange 101 will be too large in the second direction, leading to excessive material consumption of the cover plate 10 and increasing the battery cost. By limiting the value of K1, the fixing strength of the first flange 101 to the terminal 20 can be improved, making the terminal 20 less prone to displacement, thus ensuring the battery's insulation performance. It also reduces the material consumption of the cover plate 10, thereby lowering the battery cost.

[0094] K1, L1, and L2 satisfy:

[0095] 0.1 ≤ K1 × (L1 / L2) ≤ 1.7, where L1 and L2 are both in mm. For example, the value of K1 × (L1 / L2) can be 0.1, 0.15, 0.2, 0.5, 0.8, 1, 1.2, 1.5, 1.6 or 1.7, etc.

[0096] If K1×(L1 / L2) is less than 0.1, the dimension of the first flange 101 in the second direction will be too small, or the sum of the dimension of the first vertical segment 1011 of the first flange 101 in the third direction and the dimension of the first fastening segment 1012 in the first direction will be too small. This will reduce the fixing strength of the first flange 101 to the terminal 20, making the terminal 20 prone to displacement and easy to overlap with other metal parts. The insulating part 30 will not be able to perform its insulating function, resulting in insulation failure and causing a short circuit in the battery. If K1×(L1 / L2) is greater than 1.7, the dimension of the first flange 101 in the second direction will be too large, or the sum of the dimension of the first vertical segment 1011 of the first flange 101 in the third direction and the dimension of the first fastening segment 1012 in the first direction will be too large. This will result in the area of ​​the first flange 101 covering the surface of the terminal 20 being too large, leading to poor heat dissipation of the terminal 20 and poor current carrying capacity of the terminal 20. By setting K1×(L1 / L2) to be greater than or equal to 0.1 and less than or equal to 1.7, the fixing strength of the first flange 101 to the terminal post 20 can be improved, making the terminal post 20 less prone to displacement, thereby ensuring the insulation performance of the battery. It can also reduce the area of ​​the first flange 101 covering the surface of the terminal post 20, thereby improving the heat dissipation performance of the terminal post 20 and improving the current carrying capacity of the terminal post 20.

[0097] In one possible implementation, L1 and L2 satisfy: 0.35 ≤ L1 / L2 ≤ 1.9, where the units of L1 and L2 are both mm. For example, the value of L1 / L2 can be 0.35, 0.5, 0.6, 0.9, 1, 1.5, or 1.9, etc.

[0098] If L1 / L2 is less than 0.35, the sum of the dimensions of the first vertical segment 1011 of the first flange 101 in the third direction and the first fastening segment 1012 in the first direction will be too small. This will reduce the fixing strength of the first flange 101 to the terminal post 20, making the terminal post 20 prone to displacement and easy to overlap with other metal parts, resulting in insulation failure and a short circuit in the battery. If L1 / L2 is greater than 1.9, the sum of the dimensions of the first vertical segment 1011 of the first flange 101 in the third direction and the first fastening segment 1012 in the first direction will be too large. This will result in an excessively large area of ​​the first flange 101 covering the surface of the terminal post 20, leading to poor heat dissipation and poor current carrying capacity of the terminal post 20. By setting L1 / L2 to be greater than or equal to 0.35 and less than or equal to 1.9, the fixing strength of the first flange 101 to the terminal post 20 can be improved, making the terminal post 20 less prone to displacement, thereby ensuring the insulation performance of the battery. It can also reduce the area of ​​the first flange 101 covering the surface of the terminal post 20, thereby improving the heat dissipation performance of the terminal post 20 and improving the current carrying capacity of the terminal post 20.

[0099] In one possible implementation, L1 is greater than or equal to 2 mm and less than or equal to 5 mm. For example, the value of L1 can be 2 mm, 2.1 mm, 2.3 mm, 2.5 mm, 3 mm, 4 mm, 4.5 mm, or 5 mm, etc.

[0100] If L1 is less than 2mm, the sum of the dimensions of the first vertical segment 1011 of the first flange 101 in the third direction and the first fastening segment 1012 in the first direction will be too small. This will reduce the fixing strength of the first flange 101 to the terminal post 20, making the terminal post 20 prone to displacement and easy to overlap with other metal parts, resulting in insulation failure and a short circuit in the battery. If L1 is greater than 5mm, the sum of the dimensions of the first vertical segment 1011 of the first flange 101 in the third direction and the first fastening segment 1012 in the first direction will be too large. This will result in an excessively large area of ​​the first flange 101 covering the surface of the terminal post 20, leading to poor heat dissipation and poor current carrying capacity of the terminal post 20. By limiting the value of L1, the fixing strength of the first flange 101 to the terminal post 20 can be improved, making the terminal post 20 less prone to displacement, thereby ensuring the insulation performance of the battery. It can also reduce the area of ​​the first flange 101 covering the surface of the terminal post 20, thereby improving the heat dissipation performance of the terminal post 20 and improving the current carrying capacity of the terminal post 20.

[0101] In one possible implementation, L2 is greater than or equal to 2.5 mm and less than or equal to 7 mm. For example, the value of L2 can be 2.5 mm, 2.6 mm, 2.8 mm, 3 mm, 4 mm, 5 mm, 6 mm, 6.5 mm, or 7 mm, etc.

[0102] If L2 is less than 2.5mm, the sum of the dimensions of the second vertical segment 1021 of the second flange 102 in the third direction and the dimensions of the second fastening segment 1022 in the second direction will be too small. This will result in insufficient limiting effect of the second flange 102 on the insulating component 30, reduced fixing strength of the second flange 102 on the terminal post 20, and easy displacement of the terminal post 20. The terminal post 20 may also easily overlap with other metal components, leading to insulation failure and battery short circuit. If L2 is greater than 7mm, the sum of the dimensions of the second vertical segment 1021 of the second flange 102 in the third direction and the dimensions of the second fastening segment 1022 in the second direction will be too large. This will result in an excessively large area of ​​the second flange 102 covering the surface of the terminal post 20, leading to poor heat dissipation and poor current carrying capacity of the terminal post 20. By limiting the value of L2, the fixing strength of the second flange 102 to the terminal post 20 can be improved, making the terminal post 20 less prone to displacement, thereby ensuring the insulation performance of the battery. It can also reduce the area of ​​the second flange 102 covering the surface of the terminal post 20, thereby improving the heat dissipation performance of the terminal post 20 and improving the current carrying capacity of the terminal post 20.

[0103] In one possible implementation, the ratio of the dimension of the first vertical segment 1011 in the third direction to the dimension of the first fastening segment 1012 in the first direction is K2, where K2 satisfies: 0.5 ≤ K2 ≤ 2.5. For example, K2 can take values ​​such as 0.5, 0.55, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, or 2.5.

[0104] If K2 is less than 0.5, the dimension of the first vertical segment 1011 in the third direction will be too small, causing the first fastening segment 1012 of the first flange 101 to fail to press against the terminal post 20. This reduces the fixing strength of the first flange 101 to the terminal post 20, making the terminal post 20 prone to displacement and contact with other metal parts, leading to insulation failure and a short circuit in the battery. If K2 is greater than 2.5, the dimension of the first vertical segment 1011 in the third direction will be too large, resulting in a gap between the first fastening segment 1012 of the first flange 101 and the terminal post 20. This reduces the fixing strength of the first flange 101 to the terminal post 20, making the terminal post 20 prone to displacement and contact with other metal parts, leading to insulation failure and a short circuit in the battery. By limiting the ratio of the dimension of the first vertical section 1011 in the third direction to the dimension of the first fastening section 1012 in the first direction, the first fastening section 1012 of the first flange 101 presses against the pole post 20, thereby increasing the fixing strength of the first flange 101 to the pole post 20 and making the pole post 20 less prone to displacement, thus ensuring the insulation performance of the battery.

[0105] In one possible implementation, the connection between the first vertical segment 1011 and the first fastening segment 1012 is formed by cutting to create a first rounded corner 1013. The radius of the first rounded corner 1013 is r1, and r1 satisfies: 0.2mm ≤ r1 ≤ 10mm. For example, r1 can take values ​​of 0.2mm, 0.3mm, 0.5mm, 1mm, 2mm, 3mm, 5mm, 8mm, or 10mm, etc.

[0106] If r1 is less than 0.2mm, the first rounded corner 1013 will be too small, causing stress concentration and cracking at the connection between the first vertical section 1011 and the first fastening section 1012. If r1 is greater than 10mm, the first rounded corner 1013 will be too large, resulting in an insufficient area covered by the first fastening section 1012 on the pole post 20, thus reducing the fixing strength of the pole post 20. By limiting the radius of the first rounded corner 1013, stress concentration at the connection between the first vertical section 1011 and the first fastening section 1012 can be avoided, and the area covered by the first fastening section 1012 on the pole post 20 can be increased, thereby improving the fixing strength of the pole post 20.

[0107] In one possible implementation, see Figure 3 and Figure 7 As shown, the first flange 101 has a first side 1014 close to the cover body 103 and a second side 1015 away from the cover body 103 along a third direction.

[0108] In this design, the maximum dimension of the first side 1014 of the first flange 101 in the second direction is m, and the minimum dimension of the second side 1015 of the first flange 101 in the second direction is n, where m is greater than n. This setting, relative to m being equal to n, makes it easier for the first flange to be bent and shaped.

[0109] For example, n is greater than or equal to 5mm and less than or equal to 70mm. For example, the value of n can be 5mm, 10mm, 15mm, 20mm, 30mm, 40mm, 50mm, 60mm or 70mm, etc.

[0110] In some examples, m and n satisfy: 2mm ≤ mn ≤ 15mm. For example, the values ​​of mn can be 2mm, 3mm, 5mm, 8mm, 10mm, 12mm, or 15mm, etc.

[0111] If mn is less than 2mm, the difference between the maximum dimension of the first side 1014 and the minimum dimension of the second side 1015 in the second direction will be too small, causing stress concentration and cracking at the bend of the first flange 101. If mn is greater than 15mm, the difference between the maximum dimension of the first side 1014 and the minimum dimension of the second side 1015 in the second direction will be too large, resulting in the area covered by the first fastening section 1012 on the pole post 20 being too small, thus reducing the fixing strength of the first flange 101 to the pole post 20. By limiting the difference between the maximum dimension of the first side 1014 and the minimum dimension of the second side 1015 in the second direction, stress concentration at the bend of the first flange 101 can be avoided, and the fixing strength to the pole post 20 can be improved.

[0112] In one possible implementation, see Figure 5 As shown, the dimension of the first vertical segment 1011 in the first direction is A, that is, the thickness of the first vertical segment 1011 is A. A satisfies: 0.6mm ≤ A ≤ 1.5mm. For example, A can take values ​​of 0.6mm, 0.7mm, 0.75mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, or 1.5mm, etc.

[0113] If A is less than 0.6mm, the first vertical section 1011 will be too thin, resulting in insufficient connection strength between the first vertical section 1011 and the cover plate body 103, making the connection prone to cracking. If A is greater than 1.5mm, the first vertical section 1011 will be too thick, occupying too much space in the cover plate 10, resulting in insufficient space occupied by the pole post 20 and poor current carrying capacity of the pole post 20. By limiting the thickness of the first vertical section 1011, cracking at the connection between the first vertical section 1011 and the cover plate body 103 can be prevented, and the current carrying capacity of the pole post 20 can also be improved.

[0114] The dimension of the first fastening section 1012 in the third direction is B, that is, the thickness of the first fastening section 1012 is B. B satisfies: 0.6mm ≤ B ≤ 1.5mm. For example, B can take values ​​of 0.6mm, 0.7mm, 0.75mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, or 1.5mm, etc.

[0115] If B is less than 0.6mm, the first fastening section 1012 will be too thin, reducing the fixing strength of the first flange 101 to the terminal 20. This makes the terminal 20 prone to displacement and easy to overlap with other metal parts, leading to insulation failure and a short circuit in the battery. If B is greater than 1.5mm, the first fastening section 1012 will be too thick, making it easy for the busbar to overlap with the first fastening section 1012, resulting in a short circuit in the battery. By limiting the thickness of the first fastening section 1012, the fixing strength of the first fastening section 1012 to the terminal 20 is increased, making the terminal 20 less prone to displacement and preventing the busbar from overlapping with the first fastening section 1012, thereby ensuring the insulation performance of the battery.

[0116] In one possible implementation, the ratio of the dimension of the second vertical segment 1021 in the third direction to the dimension of the second fastening segment 1022 in the second direction is K3, where K3 satisfies: 0.5 ≤ K3 ≤ 2. For example, K3 can take values ​​such as 0.5, 0.55, 0.6, 0.7, 0.8, 0.9, 1, 1.5, or 2.

[0117] If K3 is less than 0.5, the dimension of the second vertical segment 1021 in the third direction will be too small, causing the second fastening segment 1022 of the second flange 102 to fail to press against the terminal post 20. This reduces the fixing strength of the second flange 102 to the terminal post 20, making the terminal post 20 prone to displacement and contact with other metal parts, leading to insulation failure and a short circuit in the battery. If K3 is greater than 2, the dimension of the second vertical segment 1021 in the third direction will be too large, resulting in a gap between the second fastening segment 1022 of the second flange 102 and the terminal post 20. This reduces the fixing strength of the second flange 102 to the terminal post 20, making the terminal post 20 prone to displacement and contact with other metal parts, leading to insulation failure and a short circuit in the battery. By limiting the ratio of the dimension of the second vertical segment 1021 in the third direction to the dimension of the second fastening segment 1022 in the second direction, the second fastening segment 1022 of the second flange 102 presses against the pole post 20, thereby increasing the fixing strength of the second flange 102 on the pole post 20 and making the pole post 20 less prone to displacement, thus ensuring the insulation performance of the battery.

[0118] In one possible implementation, see Figure 6 As shown, the dimension of the second vertical segment 1021 in the second direction is C, that is, the thickness of the second vertical segment 1021 is C. C satisfies: 0.6mm ≤ C ≤ 1.5mm. For example, C can take values ​​of 0.6mm, 0.7mm, 0.75mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, or 1.5mm, etc.

[0119] If C is less than 0.6mm, the second vertical section 1021 will be too thin, resulting in insufficient connection strength between the second vertical section 1021 and the cover plate body 103, making the connection prone to cracking. If C is greater than 1.5mm, the second vertical section 1021 will be too thick, occupying too much space in the cover plate 10, resulting in insufficient space occupied by the pole post 20 and poor current-carrying capacity of the pole post 20. By limiting the thickness of the second vertical section 1021, cracking at the connection between the second vertical section 1021 and the cover plate body 103 can be prevented, and the current-carrying capacity of the pole post 20 can be improved.

[0120] The dimension of the second fastening section 1022 in the third direction is D, that is, the thickness of the second fastening section 1022 is D. D satisfies: 0.6mm≤D≤1.5mm. For example, D can take values ​​of 0.6mm, 0.7mm, 0.75mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, or 1.5mm, etc.

[0121] If D is less than 0.6mm, the second fastening section 1022 will be too thin, reducing the fixing strength of the second flange 102 to the terminal 20. This makes the terminal 20 prone to displacement and easy to overlap with other metal parts, leading to insulation failure and a short circuit in the battery. If D is greater than 1.5mm, the second fastening section 1022 will be too thick, making it easy for the busbar to overlap with the second fastening section 1022, resulting in a short circuit in the battery. By limiting the thickness of the second fastening section 1022, the fixing strength of the second fastening section 1022 to the terminal 20 is increased, making the terminal 20 less prone to displacement and preventing the busbar from overlapping with the second fastening section 1022, thereby ensuring the insulation performance of the battery.

[0122] Wherein, the dimension of the second vertical segment 1021 in the second direction is equal to the dimension of the first vertical segment 1011 in the first direction, that is, C equals A. This setting allows the thickness of the second vertical segment 1021 to be the same as the thickness of the first vertical segment 1011, making it easier to form when the first flange 101 and the second flange 102 are stretched and bent from the cover plate 10, and at the same time improving the overall fixing strength of the flange to the pole post 20.

[0123] In one possible implementation, the connection between the second vertical segment 1021 and the second fastening segment 1022 is formed by cutting to create a second rounded corner 1023. The radius of the second rounded corner 1023 is r2, which satisfies the condition: 0.2mm ≤ r2 ≤ 10mm. For example, r2 can take values ​​of 0.2mm, 0.3mm, 0.5mm, 1mm, 2mm, 3mm, 5mm, 8mm, or 10mm, etc.

[0124] If r2 is less than 0.2mm, the second rounded corner 1023 will be too small, causing stress concentration and cracking at the connection between the second vertical section 1021 and the second fastening section 1022. If r2 is greater than 10mm, the second rounded corner 1023 will be too large, resulting in an insufficient area covered by the second fastening section 1022 on the pole post 20, thus reducing the fixing strength of the pole post 20. By limiting the radius of the second rounded corner 1023, stress concentration at the connection between the second vertical section 1021 and the second fastening section 1022 can be avoided, and the area covered by the second fastening section 1022 on the pole post 20 can be increased, thereby improving the fixing strength of the pole post 20.

[0125] In some examples, r2 > r1. It should be noted that when r2 equals r1, the first flange 101 is more prone to deformation under external force compared to the second flange 102, resulting in a lower fixing strength of the first flange 101 to the pole post 20. By making r1 less than r2, the contact area between the first flange 101 and the pole post 20 can be increased, thereby improving the fixing strength of the first flange 101 to the pole post 20, and thus balancing the fixing strength of the first flange 101 and the second flange 102 to the pole post 20.

[0126] In one possible implementation, see Figure 7 As shown, the first flange 101 and the second flange 102 are connected by a connecting segment 105.

[0127] In the third direction, the size of the connecting section 105 is less than or equal to the size of the first vertical section 1011 or the size of the second vertical section 1021. With this configuration, the first fastening section 1012 of the first flange 101 or the second fastening section 1022 of the second flange 102 protrudes from the connecting section 105, facilitating the fixation of the pole post 20 by the first fastening section 1012 or the second fastening section 1022.

[0128] The connecting section 105 is arc-shaped. In the third direction, the dimension of the connecting section 105 is F. F is greater than or equal to 0.2 mm and less than or equal to 1 mm. The value of F can be 0.2 mm, 0.25 mm, 0.3 mm, 0.5 mm, 0.7 mm, 0.9 mm, or 1 mm, etc. This design prevents foreign objects from entering between the pole post 20 and the cover plate 10.

[0129] It should be noted that if the connecting segment 105 extends beyond the first vertical segment 1011, material accumulation will occur at the connection between the connecting segment 105 and the first fastening segment 1012, leading to cracking. By ensuring that the dimension of the connecting segment 105 is less than or equal to the dimension of the first vertical segment 1011 in the third direction, and thus preventing the connecting segment 105 from extending beyond the first vertical segment 1011, cracking can be avoided.

[0130] If the connecting segment 105 extends beyond the second vertical segment 1021, material accumulation will occur at the connection between the connecting segment 105 and the second fastening segment 1022, leading to cracking. By ensuring that the dimension of the connecting segment 105 is less than or equal to the dimension of the second vertical segment 1021 in the third direction, and thus preventing the connecting segment 105 from extending beyond the second vertical segment 1021, cracking can be avoided.

[0131] In another possible implementation, see Figure 8 As shown, the first flange 101 and the second flange 102 are spaced apart, that is to say, there is no connecting segment between the first flange 101 and the second flange 102.

[0132] The distance E between the first flange 101 and the second flange 102 is greater than or equal to 1 mm and less than or equal to 5 mm. The value of E can be 1 mm, 1.25 mm, 1.5 mm, 2 mm, 3 mm, 4 mm or 5 mm, etc.

[0133] In one possible implementation, see Figure 6As shown, in the third direction, the size of the area where the pole post 20 overlaps with the first fastening section 1012 and / or the second fastening section 1022 is G1. Specifically, in the third direction, the size of the area where the pole post 20 overlaps with the first fastening section 1012 is G1. Or, in the third direction, the size of the area where the pole post 20 overlaps with the second fastening section 1022 is G1. Or, in the third direction, the size of the area where the pole post 20 overlaps with the first fastening section 1012 and the second fastening section 1022 is G1.

[0134] The dimension of pole 20 in the third direction is G2.

[0135] The ratio of G1 to G2 is greater than or equal to 0.6 and less than or equal to 1.5. The units for both G1 and G2 are mm. For example, the ratio of G1 to G2 can be 0.6, 0.7, 0.9, 1, 1.2, 1.4, or 1.5, etc.

[0136] If the ratio of G1 to G2 is less than 0.6, the area where the pole post 20 overlaps with the first fastening section 1012 and / or the second fastening section 1022 in the third direction is too small, resulting in insufficient fixing strength of the cover plate 10 to the pole post 20. If the ratio of G1 to G2 is less than 1.5, the area where the pole post 20 overlaps with the first fastening section 1012 and / or the second fastening section 1022 in the third direction is too large, resulting in at least one of the first flanges 101 and the second flange 102 having an excessively large size in the third direction, which will affect the installation of the busbar. By ensuring that the ratio of G1 to G2 is greater than or equal to 0.6 and less than or equal to 1.5, the fixing strength of the cover plate 10 to the pole post 20 can be improved without affecting the installation of the busbar.

[0137] In some examples, the first flange 101 and / or the second flange 102 are integrally formed with the cover body 103. Specifically, the first flange 101 may be integrally formed with the cover body 103. Alternatively, the second flange 102 may be integrally formed with the cover body 103. Or, the first flange 101 and the second flange 102 may be integrally formed with the cover body 103.

[0138] In some examples, the first flange 101 and / or the second flange 102 are separate structures from the cover plate body 103. Specifically, the first flange 101 and the cover plate body 103 are separate structures, and the first flange 101 and the cover plate body 103 are connected by welding. Alternatively, the second flange 102 and the cover plate body 103 are separate structures, and the second flange 102 and the cover plate body 103 are connected by welding. Or, the first flange 101 and the second flange 102 and the cover plate body 103 are separate structures, and the first flange 101 and the second flange 102 are connected to the cover plate body 103 by welding.

[0139] In one possible implementation, the cover plate assembly 100 further includes a seal 40. The seal 40 is at least partially located in the mounting hole 104 and is disposed between the electrode post 20 and the cover plate 10. The seal 40 is used to seal between the electrode post 20 and the cover plate 10 to prevent electrolyte leakage between the electrode post 20 and the cover plate 10.

[0140] In some examples, the seal 40 may be made of an insulating, elastic material. For example, the material of the seal 40 includes, but is not limited to, silicone, fluororubber, soluble polytetrafluoroethylene, or polytetrafluoroethylene.

[0141] In one possible implementation, the pole post 20 is provided with a step.

[0142] The first fastening section 1012 and / or the second fastening section 1022 are pressed against the step of the pole post 20 by the insulating member 30. Alternatively, the second fastening section 1022 is pressed against the step of the pole post 20 by the insulating member 30.

[0143] It should be noted that when the first fastening section 1012 and the second fastening section 1022 are pressed onto the step of the pole post 20 by the insulating member 30, in the third direction, the first fastening section 1012 and the second fastening section 1022 can be located on the top of the pole post 20 near the cell 300. That is, in the third direction, the first fastening section 1012 and the second fastening section 1022 are lower than the top of the pole post 20, which can prevent the flange from being too high in the third direction and avoid affecting the installation of the pole post 20 and the busbar.

[0144] See in some examples Figure 9 As shown, the pole post 20 includes a pole post body 201, a first protrusion 202, and a second protrusion 203. The second protrusion 203 is disposed on the outer ring of the pole post body 201, and the first protrusion 202 is disposed on the outer ring of the second protrusion 203. The first protrusion 202 and the second protrusion 203 form a first step, and the first flange 101 is fixed on the first step, that is, the first fastening section 1012 is pressed on the first step by the insulating member 30.

[0145] In some examples, the first fastening section 1012 is spaced apart from the pole post 20 on the side facing upwards in the third direction, and the second fastening section 1022 is also spaced apart from the pole post 20 on the side facing upwards in the third direction. The insulating member 30 is at least partially disposed in the gap between the first fastening section 1012 and the pole post 20 on the third direction, and at least partially disposed in the gap between the second fastening section 1022 and the pole post 20 on the third direction. This arrangement improves the insulation between the flange and the pole post 20.

[0146] In some examples, the insulating element 30 is at least partially located between the first fastening section 1012 and the second protrusion 203, with the second protrusion 203 forming a second step with the pole body 201. This arrangement can increase the creepage distance and improve the insulation safety between the pole 20 and the first flange 101.

[0147] In one possible implementation, see Figure 10 As shown, the pole post 20 includes a first body 20a and a second body 20b. The first body 20a is located on top of the second body 20b, that is, the first body 20a is located on the side of the second body 20b facing away from the cell 300 in the third direction.

[0148] The first main body 20a is an aluminum component, that is, the first main body 20a is made of aluminum.

[0149] The second body 20b is made of copper, that is, the second body 20b is made of copper.

[0150] The first body 20a and the second body 20b are integrally formed. In some examples, the contact surfaces of the first body 20a and the second body 20b are integrally formed under pressure in a plastic state.

[0151] Secondly, embodiments of this application provide a battery, including a housing 200 and a cover assembly 100 as described in the first aspect; the cover assembly 100 is connected to the housing 200.

[0152] The battery in this embodiment includes the cover plate assembly 100 in the aforementioned embodiments, which can ensure the insulation performance of the battery, improve the heat dissipation performance of the terminal 20, and improve the current carrying capacity of the terminal 20.

[0153] Thirdly, embodiments of this application provide a battery pack including a plurality of batteries as described in the second aspect.

[0154] The battery pack in this embodiment includes the battery described in the previous embodiment, which can ensure the insulation performance of the battery, improve the heat dissipation performance of the terminal 20, and improve the current carrying capacity of the terminal 20.

[0155] The battery provided in this application will be described in detail below through specific embodiments.

[0156] If K1×(L1 / L2) is too small, a short circuit will occur between the housing 200 and the terminal 20. The test method is as follows:

[0157] Batteries were manufactured using the parameters in Table 1 below. 100 batteries were taken for each embodiment and comparative example. For each battery, it was placed in a vibration table and subjected to random vibration in the Z / Y / X directions and sinusoidal fixed-frequency vibration for 12 hours and 2 hours respectively, in accordance with the national standard GB38031-2020.8.2.

[0158] At 25°C, the lithium-ion batteries of each embodiment and comparative example that have undergone vibration testing were subjected to cyclic testing according to the following procedure.

[0159] For lithium iron phosphate batteries: (1) Charge at a constant current of 1C to 3.65V, and charge at a constant voltage until the current drops to 0.05C; (2) Let stand for 30 minutes; (3) Discharge at a constant current of 1C to 2.5V; (4) Let stand for 30 minutes. Repeat steps (1) to (4) for 20 cycles. Set the alarm current value of the withstand voltage tester to 0.1mA and the voltage value between the two output terminals to 1kV. Connect the battery casing and the terminal to the two output terminals of the withstand voltage tester respectively, and apply the set voltage value. If the withstand voltage tester alarms, it is determined that there is a short circuit between the terminal and the casing, and the insulation performance is unqualified; if the withstand voltage tester does not alarm, it is determined that there is no short circuit between the terminal and the casing, and the insulation performance is qualified. Measure 100 batteries and calculate the pass rate. A pass rate ≥ 96% is qualified, otherwise it is unqualified.

[0160] For ternary lithium batteries: (1) Charge at a constant current rate of 1C to 4.35V, and charge at a constant voltage rate until the current drops to 0.05C; (2) Let stand for 20 minutes; (3) Discharge at a constant current rate of 1C to 2.75V; (4) Let stand for 20 minutes. Repeat steps (1) to (4) for 20 cycles. Set the alarm current value of the withstand voltage tester to 0.1mA and the voltage value between the two output terminals to 1kV. Connect the battery casing and terminals to the two output terminals of the withstand voltage tester respectively, and apply the set voltage value. If the withstand voltage tester alarms, it is determined that there is a short circuit between the terminals and the casing, and the insulation performance is unqualified; if the withstand voltage tester does not alarm, it is determined that there is no short circuit between the terminals and the casing, and the insulation performance is qualified. Measure 100 batteries and calculate the pass rate. A pass rate ≥ 96% is qualified, otherwise it is unqualified.

[0161] This test example uses a lithium iron phosphate battery.

[0162] If K1×(L1 / L2) is too large, the electrode 20 will be more prone to temperature rise. The test method is as follows:

[0163] Terminal temperature rise test: A battery is fabricated using the parameters in Table 1 below. At 25°C, connect the terminal 20 to a temperature sensor, charge the battery at a constant current at a rate of 4C until the voltage of the battery reaches the upper limit voltage, then switch to constant voltage charging until the current of the battery drops to 0.05C. Record the temperature change of the terminal 20 during the entire charging process. If the maximum temperature T of the terminal 20 is less than or equal to 45°C, the test result is considered qualified; if the maximum temperature T of the terminal is greater than 45°C, it is determined as unqualified.

[0164] It should be noted that for different battery systems, the upper and lower limit voltages need to be adjusted accordingly: the upper limit voltage of a lithium iron phosphate (LFP) battery is 3.65V and the lower limit voltage is 2.5V; the upper limit voltage of a nickel cobalt manganese lithium (NCM) battery is 4.25V and the lower limit voltage is 2.5V; the upper limit voltage of a lithium manganese iron phosphate (LFMP) battery is 4.25V and the lower limit voltage is 2.5V; the upper limit voltage of a lithium nickel manganese oxide battery is 4.8V and the lower limit voltage is 3.5V.

[0165] This test example takes a lithium iron phosphate battery as an example.

[0166] Table 1 Test parameters and results

[0167]

[0168] Compared with Comparative Example 1 and Comparative Example 3, when K1, L1 and L2 satisfy 0.1 ≤ K1 × (L1 / L2), the qualification rate of the battery is all greater than or equal to 96%. Limiting K1, L1 and L2 can ensure the insulation performance of the battery.

[0169] Compared with Comparative Example 2 and Comparative Example 4, when K1, L1 and L2 satisfy K1 × (L1 / L2) ≤ 1.7, the temperature of the terminal is all less than 45°C. Limiting K1, L1 and L2 can ensure the heat dissipation performance of the terminal and guarantee the overcurrent capability of the terminal.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or equivalently replace some or all of the technical features; and such modifications or substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A cover assembly, characterized by include: A cover plate, wherein the cover plate is provided with mounting holes, two first flanges and two second flanges, the two first flanges are provided on opposite sides of the mounting holes in a first direction, and the two second flanges are provided on opposite sides of the mounting holes in a second direction, and the first flanges and the second flanges are located on the same side of the plane on which the top of the mounting holes are located; The pole is fixed in the mounting hole by the first flange and the second flange. An insulating element is provided between the pole and the cover plate. The ratio of the size of the pole in the second direction to the size of the pole in the first direction is greater than or equal to 1.5 and less than or equal to 8. The first flange includes a first vertical segment extending along a third direction and a first fastening segment extending along the first direction; the second flange includes a second vertical segment extending along the third direction and a second fastening segment extending along the second direction. In the second direction, the ratio of the size of the first flange to the size of the pole post is K1; The first direction, the second direction, and the third direction are perpendicular to each other; The sum of the dimension of the first vertical segment in the third direction and the dimension of the first fastening segment in the first direction is L1, and the sum of the dimension of the second vertical segment in the third direction and the dimension of the second fastening segment in the second direction is L2; K1, L1, and L2 satisfy the condition: 0.1 ≤ K1 × (L1 / L2) ≤ 1.7, where the units of L1 and L2 are both mm.

2. The cover plate assembly of claim 1, wherein, The L1 and L2 satisfy the condition: 0.35≤L1 / L2≤1.9, where the units of L1 and L2 are both mm.

3. The cover plate assembly of claim 1, wherein, The condition K1 satisfies: 0.2≤K1≤1.

4. The cover plate assembly of claim 1, wherein, The ratio of the dimension of the first vertical segment in the third direction to the dimension of the first fastening segment in the first direction is K2, wherein K2 satisfies: 0.5≤K2≤2.

5.

5. The cover plate assembly of claim 1, wherein, A first rounded corner is provided at the connection between the first vertical section and the first fastening section. The radius of the first rounded corner is r1, and r1 satisfies: 0.2mm≤r1≤10mm.

6. The cover plate assembly of claim 1, wherein, The cover plate is provided with a cover plate body connected to the first flange and the second flange. The first flange has a first side close to the cover plate body and a second side away from the cover plate body along the third direction. The maximum dimension of the first side in the second direction is m, and the minimum dimension of the second side in the second direction is n, where m is greater than n.

7. The cover plate assembly according to claim 6, characterized in that, The m and n satisfy the condition: 2mm≤mn≤15mm.

8. The cover plate assembly according to claim 1, characterized in that, The dimension of the first vertical segment in the first direction is A, and A satisfies: 0.6mm ≤ A ≤ 1.5mm; The dimension of the first fastening segment in the third direction is B, and B satisfies: 0.6mm≤B≤1.5mm.

9. The cover plate assembly according to claim 1, characterized in that, The ratio of the dimension of the second vertical segment in the third direction to the dimension of the second fastening segment in the second direction is K3, wherein K3 satisfies: 0.5≤K3≤2.

10. The cover plate assembly according to claim 1, characterized in that, The dimension of the second vertical segment in the second direction is C, wherein C satisfies: 0.6mm ≤ C ≤ 1.5mm; The dimension of the second fastening section in the third direction is D, and D satisfies: 0.6mm≤D≤1.5mm.

11. The cover plate assembly according to claim 1, characterized in that, A second rounded corner is provided at the connection between the second vertical section and the second fastening section. The radius of the second rounded corner is r2, and r2 satisfies: 0.2mm≤r2≤10mm.

12. The cover plate assembly according to claim 1, characterized in that, A first rounded corner is provided at the connection between the first vertical segment and the first fastening segment, and a second rounded corner is provided at the connection between the second vertical segment and the second fastening segment. The radius of the first rounded corner is r1, and the radius of the second rounded corner is r2. The r2 and the r1 satisfy: r2 > r1.

13. The cover plate assembly according to claim 1, characterized in that, The ratio of the dimension of the cover plate in the second direction to the dimension of the cover plate in the first direction is greater than or equal to 2.6 and less than or equal to 14.

14. The cover plate assembly according to any one of claims 1-13, characterized in that, The electrode post includes an electrode post body, a first protrusion and a second protrusion, the second protrusion being disposed on the outer ring of the electrode post body, and the first protrusion being disposed on the outer ring of the second protrusion; The first protrusion and the second protrusion form a first step, and the first flange is fixed on the first step.

15. The cover plate assembly according to claim 14, characterized in that, The insulating element is at least partially located between the first fastening section and the second protrusion, and the second protrusion forms a second step with the pole body.

16. The cover plate assembly according to any one of claims 1-13, characterized in that, The pole post includes a first body and a second body. The first body is made of aluminum and the second body is made of copper. The first body is located on top of the second body and the first body and the second body are integrally formed.

17. The cover plate assembly according to any one of claims 1-13, characterized in that, In the three directions, the dimensions of the first vertical segment are the same as those of the second vertical segment, and the dimensions of the first vertical segment are greater than or equal to 1 mm and less than or equal to 3 mm.

18. The cover plate assembly according to any one of claims 1-13, characterized in that, In the first direction, the size of the first fastening segment is greater than or equal to 1 mm and less than or equal to 3 mm; and / or, in the second direction, the size of the second fastening segment is greater than or equal to 0.8 mm and less than or equal to 2 mm.

19. A battery, characterized in that, It includes a housing and a cover assembly as described in any one of claims 1-18; the cover assembly is connected to the housing.

20. A battery pack, characterized in that, Includes multiple batteries as described in claim 19.

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