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 mounting hole comprises an assembling hole section and a riveting hole section which are runway-shaped holes, the pole before riveting comprises a pole main body, the pole main body comprises a first pole section and a second pole section, the pole main body penetrates through the assembling hole and the pole mounting hole, and the top surface of the second pole section is higher than the top surface of the riveting hole section; an annular gap is formed between the second pole section and the riveting hole section to form a thrust bearing area, the riveted second pole section forms an assembly column section and a riveting column section, and a concave riveting groove is formed in the top of the riveting column section under riveting force; and a preset condition is met between the pole and the riveting block. According to the invention, after the terminal post is riveted, the arc edge of the terminal post is fully expanded, the integral riveting strength of the battery cell cover plate assembly is ensured, and the reliability and safety of the battery cell are 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 continuous advancement of battery technology and the expansion of its application scope, people's requirements for overall battery performance and safety have gradually increased. As one of the key components of battery packaging, the assembly quality of the cell cover assembly affects the overall performance and safety of the battery.

[0003] The battery cell cover plate assembly includes a cover plate, a pole and a rivet block. Among them, the pole is a key part for connecting to the external circuit, while the cover plate plays a role of sealing and protection. During the assembly process, the pole and the cover plate are fixed by a rivet block. When the pole and the rivet block are riveted, vertical pressure is applied to the pole from the center axis position of the pole, causing the top of the pole to swell and deform, thereby achieving riveting with the rivet block. In commonly used battery cell cover plate assemblies, the pole is divided into two structures, one is a circular pole and the other is an oblong pole (also commonly known as an elliptical pole). The oblong pole includes a straight edge and an arc edge. In the existing oblong pole cover plate structure, when the riveting force is applied to the pole, there is a problem of difference in material expansion during the riveting process of the arc edge and the straight edge, that is, the arc edge of the pole has weaker material expansion ability than the straight edge of the pole, and the arc edge of the pole has insufficient material expansion.

[0004] This difference in material expansion will cause a gap between the pole and the rivet block, resulting in insufficient riveting strength of the cover plate, mechanical strength unable to meet design requirements, poor thrust resistance, and affecting the reliability and safety of the battery cell. 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 problems of insufficient riveting strength of the cover and poor thrust resistance caused by insufficient expansion of the arc edge of the elliptical pole.

[0006] In the first aspect, the present invention provides a battery cell cover plate assembly, including a cover plate, a rivet block and a pole. The cover plate is provided with an assembly hole; the rivet block is a rectangular structure, and the rivet block is provided with a pole mounting hole, and the pole mounting hole is a stepped hole, including an assembly hole section and a rivet hole section, and both the assembly hole section and the rivet hole section are runway-shaped holes; the pole before riveting includes a pole body, and the pole body includes a first pole section that cooperates with the assembly hole and a second pole section that cooperates with and is riveted to the pole mounting hole, and the pole body is sequentially passed through the assembly hole and the pole mounting hole, the top surface of the second pole section is higher than the top surface of the rivet hole section, and an annular gap is provided between the second pole section and the rivet hole section to form a thrust bearing area, the pole body is riveted to the rivet block, and the second pole section after riveting forms an assembly column section that cooperates with the assembly hole section and a rivet column section that cooperates with the rivet hole section, the rivet column section fills the thrust bearing area, and the top of the rivet column section is formed with a concave rivet groove by the riveting force;

[0007] The requirements between the pole and the riveted block are:

[0008]

[0009] in,

[0010] h1 is the height of the top surface of the second pole segment above the top surface of the riveting hole segment along the Z direction before riveting, in mm;

[0011] S1 is the cross-sectional area of ​​the second pole segment along the XY plane before riveting, in mm 2 ;

[0012] S2 is the projection area of ​​the thrust bearing area along the Z direction, in mm 2 ;

[0013] h2 is the depth of the riveting hole section along the Z direction, in mm;

[0014] V0 is the volume of the riveting groove, in mm3.

[0015] Beneficial Effects: The battery cell cover assembly provided by the present invention, by increasing the volume of the pole body and adding a material expansion compensation height h1, can compensate for the volume of the expanded material on the arc edge of the elliptical pole during the riveting process, solving the problem of insufficient material expansion on the arc edge of the elliptical pole, ensuring that the arc edge of the pole is fully expanded after riveting, the arc edge of the thrust support area is fully filled, and there is no gap between the pole and the riveted block, thereby ensuring the overall riveting strength of the battery cell cover assembly, so that its mechanical strength meets the design requirements, and its thrust resistance performance meets the requirements, thereby ensuring the reliability and safety of the battery cell. At the same time, there is no gap between the pole and the riveted block, which can ensure the welding quality between the pole and the riveted block, further improving the reliability and safety of the battery.

[0016] At the same time, the present invention provides a calculation formula for the expansion compensation height h1: h1 = (S2×h2-V0) / S1. The expansion compensation height h1 can be calculated through this formula, so that a reasonable expansion compensation height can be designed for the pole, which can not only compensate for the expansion volume of the arc edge of the pole, but also prevent the expansion compensation height from being too large, causing the straight edge of the pole to expand excessively and causing local deformation of the rivet block, thereby ensuring that the rivet block and the external insulating part can be assembled normally, and realizing precise control of the expansion volume of the pole during the riveting process, which helps to ensure production consistency and reduce the defective product rate.

[0017] In an optional embodiment, the following conditions are also met:

[0018] 20mm 2 ≤S1≤180mm 2 ,

[0019] 25mm 2 ≤S2≤250mm 2 ,

[0020] 0.55mm≤h2≤1.65mm.

[0021] In an optional embodiment, the following conditions are also met:

[0022] 5mm 3 ≤V0≤35mm 3 .

[0023] In an optional embodiment, the following conditions are also met:

[0024]

[0025] 0.85mm≤h3≤2.5mm,

[0026] 1.5mm≤T≤3.5mm,

[0027] in,

[0028] h3 is the depth of the assembly hole segment along the Z direction, in mm.

[0029] T is the total thickness of the riveted block along the Z direction, in mm.

[0030] In an optional embodiment, the following conditions are also met:

[0031]

[0032] Where W is the width of the thrust bearing area along the XY plane, in mm.

[0033] h3 is the depth of the assembly hole segment along the Z direction, in mm.

[0034] In an optional embodiment, it is also satisfied that the error of h1 is between -0.1 mm and +0.1 mm.

[0035] In an optional embodiment, the side wall of the riveting hole segment is parallel to the central axis of the pole mounting hole, and the riveting hole segment is connected to the assembly hole segment via an annular step surface.

[0036] In an optional embodiment, the pole mounting hole also includes a welding sinker provided on the top of the riveted hole section. The size of the welding sinker is larger than the size of the riveted hole section along the X direction and the Y direction, and the top surface of the riveted column section is lower than the welding sinker.

[0037] In a second aspect, the present invention further provides a battery cell comprising a housing, a pole group, and the cell cover assembly described in the above technical solution. The housing has a receiving cavity and an opening communicating with the receiving cavity; the pole group is disposed in the housing cavity; and the cell cover assembly is disposed in the opening of the housing, encapsulating the pole group within the housing.

[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 charging and discharging process of the battery cell. 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 a crucial component of the battery cell and ensures 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 This is a structural schematic diagram of a riveted block in a battery cell cover assembly according to an embodiment of the present invention;

[0044] Figure 2 for Figure 1 A top view of the riveted block is shown;

[0045] Figure 3 For the Figure 2 Cross-sectional view at CC;

[0046] Figure 4 For the Figure 2 Cross-sectional view at DD in the middle;

[0047] Figure 5 For Figure 1 The schematic diagram of the structure of the pole to which the riveting block is adapted before riveting is shown;

[0048] Figure 6 for Figure 5 A top view of

[0049] Figure 7 For the Figure 6 Cross-sectional view at FF;

[0050] Figure 8 For the Figure 6 Cross-sectional view at EE;

[0051] Figure 9 A top view of a battery cell cover assembly according to an embodiment of the present invention;

[0052] Figure 10 for Figure 9 The cell cover assembly shown is at the front edge of the pole riveting Figure 9 Cross-sectional view at AA in the middle;

[0053] Figure 11 for Figure 10 A partial enlarged view of point G in the middle;

[0054] Figure 12 for Figure 9 The cell cover assembly shown is at the front edge of the pole riveting Figure 9 Cross-sectional view at the middle BB;

[0055] Figure 13 for Figure 9 The battery cover assembly shown is at the rear edge of the pole riveting Figure 9 Cross-sectional view at AA in the middle;

[0056] Figure 14 for Figure 13 A partial enlarged view of the H in the middle;

[0057] Figure 15 This is a schematic structural diagram of a battery cell cover assembly before and after riveting according to an embodiment of the present invention;

[0058] Figure 16 for Figure 15 An exploded view of the cell cover assembly is shown;

[0059] Figure 17 Schematic diagram of the structure of the pole after riveting.

[0060] Description of reference numerals:

[0061] 1. Cover plate; 101. Assembly hole; 2. Riveted block; 201. Pole mounting hole; 2011. Assembly hole section; 2012. Riveted hole section; 2013. Welding sinker; 2014. Thrust support area; 3. Pole; 301. Pole body; 3011. First pole section; 3012. Second pole section; 30121. Assembly column section; 30122. Riveted column section; 30123. Riveted groove; 302. Pole base plate; 4. First insulating member; 5. Second insulating member; 6. Sealing ring; 7. Explosion-proof valve; 8. Explosion-proof valve patch. DETAILED DESCRIPTION

[0062] 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.

[0063] Since the volume of the space before and after the elliptical pole is expanded, and there is a difference in the expansion of the arc edge and the straight edge of the elliptical pole, the top surface of the pole before riveting in the related art is flush with the top surface of the riveting hole section of the riveting block. The expanded material of the pole will not be able to fill the endurance support area between the riveting block and the pole, resulting in insufficient riveting strength of the cover plate. At the same time, the gap between the pole and the riveting block will also affect the welding quality, further reducing the reliability and safety of the battery. Therefore, the problem of inconsistent expansion of the straight edge and the arc edge of the elliptical pole after riveting will pose a potential threat to the overall performance and safety of the battery.

[0064] To this end, the present invention proposes a solution, which presets a material expansion compensation height for the pole before riveting, so that the height of the elliptical pole before riveting exceeds the height of the rivet hole section 2012 of the riveting block 2. By utilizing the basic principle of volume change such as material expansion of the pole 3, the preset material expansion compensation height value h1 of the pole 3 is calculated through a relationship, so as to reasonably compensate for the volume of the elliptical pole during riveting, thereby ensuring the riveting strength of the cover plate 1.

[0065] The following combination Figures 1 to 17 , describing embodiments of the present invention.

[0066] 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 a rectangular structure, and the rivet block 2 is provided with a pole mounting hole 201. The pole mounting hole 201 is a stepped hole, comprising an assembly hole section 2011 and a rivet hole section 2012. Both the assembly hole section 2011 and the rivet hole section 2012 are runway-shaped holes. The pole 3 before riveting comprises a pole body 301, which comprises a first pole section 3011 that cooperates with the assembly hole 101 and a second pole section 3012 that cooperates with and is riveted to the pole mounting hole 201. The pole body 301 is sequentially passed through the assembly hole 101 and the pole mounting hole 201. The top surface of the second pole segment 3012 is higher than the top surface of the riveting hole segment 2012. An annular gap is formed between the second pole segment 3012 and the riveting hole segment 2012 to form a thrust bearing area 2014. The pole body 301 is riveted to the riveting block 2. After riveting, the second pole segment 3012 forms an assembly column segment 30121 that cooperates with the assembly hole segment 2011 and a riveted column segment 30122 that cooperates with the riveted hole segment 2012. The riveted column segment 30122 fills the thrust bearing area 2014. A concave rivet groove 30123 is formed on the top of the riveted column segment 30122 due to the riveting force.

[0067] The conditions between the pole 3 and the riveted block 2 are as follows:

[0068]

[0069] in,

[0070] h1 is the height of the top surface of the second pole segment 3012 above the top surface of the riveting hole segment 2012 along the Z direction before riveting, in mm;

[0071] S1 is the cross-sectional area of ​​the second pole segment 3012 before riveting along the XY plane, in mm 2 ;

[0072] S2 is the projection area of ​​the thrust bearing area 2014 along the Z direction, in mm 2 ;

[0073] h2 is the depth of the riveting hole section 2012 along the Z direction, in mm;

[0074] V0 is the volume of the rivet groove 30123, in mm3.

[0075] In the embodiment provided by the present invention, the battery cell cover plate assembly can be applied to blade battery cells. The cover plate 1 is a rectangular structure, and the rivet block 2 is also a rectangular structure to match it. At the same time, the pole mounting hole 201 of the rivet block 2 is correspondingly set to a runway-shaped hole, or an oblong hole. After the pole 3 is riveted, it expands and deforms, and the final structure is adapted to the shape of the pole mounting hole 201 of the rivet block 2.

[0076] Specifically,

[0077] S1 is the cross-sectional area of ​​the pole body 301 along the XY plane. Figure 6 In the figure, S1 is represented by the area of ​​the black shaded block.

[0078] S2 is the projection area of ​​the thrust support area 2014 along the Z direction. Figure 2 In , S2 is represented by the area of ​​the black annular shaded block. Figure 11 and Figure 12 , the thrust bearing area 2014 is indicated by a black shaded block.

[0079] V0 is the volume of the rivet groove 30123. The rivet groove 30123 is a blind hole. The volume V0 of the rivet groove 30123 is as follows: Figure 14 The volume of the area indicated by the black shaded block.

[0080] The present invention provides a cell cover assembly, wherein the structure of the pole 3 changes before and after riveting. In the embodiment provided by the present invention, the structure of the pole 3 before riveting is as follows: Figures 5 to 8 As shown, since the assembly hole section 2011 and the riveting hole section 2012 of the riveting block 2 are both racetrack-shaped holes, the cross-sectional shape of the pole body 301 adapted to the assembly hole section 2011 along the radial direction is a waist-shaped circle, that is, an oblong pole, also commonly known as an elliptical pole. The structure of the pole 3 after riveting is as follows Figure 17 As shown, after riveting, the pole body 301 forms an assembly column section 30121 that cooperates with the assembly hole section 2011 and a riveted column section 30122 that cooperates with the riveted hole section 2012. The riveted column section 30122 fills the thrust bearing area 2014, and the top of the riveted column section 30122 is formed with a concave rivet groove 30123 due to the riveting force.

[0081] There is an annular gap between the pole body 301 and the riveted hole section 2012, which constitutes the thrust support area 2014. During the riveting process between the pole 3 and the riveted block 2, the upper end of the pole body 301 will expand and deform toward the thrust support area 2014 under the action of the riveting force until the entire thrust support area 2014 is filled. At this time, the undeformed portion of the pole body 301 still cooperates with the assembly hole section 2011 of the pole mounting hole 201 and the assembly hole 101 of the cover plate to form the assembly column section 30121. The expanded and deformed portion adapts to the riveted hole section 2012 of the pole mounting hole 201 to form the riveted column section 30122. The thrust support area 2014 is used to support and accommodate the expanded portion of the pole 3 to form the riveted column section 30122, thereby achieving the connection between the cover plate 1, the riveted block 2, and the pole 3. Specifically, after the pole 3 and the rivet block 2 are riveted, the pole 3 expands to form a riveted column section 30122 that fills the thrust support area 2014. This structure is used to withstand the thrust load exerted on the cell cover assembly in the battery pack and is a very important structure in the cell cover assembly.

[0082] Reference Figure 11 The section from the top of the pole body 301 to the bottom of the thrust support area 2014 is the expansion and deformation section of the pole 3. It deforms under the riveting force, and its total height is the sum of h1 and h2. The section indicated by height h1 is the expansion compensation section. For ease of description, h1 is simply referred to as the expansion compensation height.

[0083] Based on the principle of equal volume flow in material expansion theory, in related art cell cover plate assemblies, the top surface of the terminal body 301 is typically flush with the top surface of the rivet hole section 2012 of the rivet block 2, without considering the differential material expansion between the arc and straight edges of the elliptical terminal. In particular, the longer or wider the elliptical terminal, the more difficult it is to rivet and expand the material, the more uneven the material flow of the terminal 3 will be, and the more obvious the differential material expansion between the arc and straight edges will be.

[0084] In order to solve this technical problem, the present invention provides a cell cover plate assembly, wherein, by increasing the volume of the expanded deformation section of the pole 3 and adding an expansion compensation height h1, the expansion of the arc edge of the elliptical pole during the riveting process can be compensated, solving the problem of insufficient expansion of the arc edge of the elliptical pole, ensuring that the arc edge of the pole 3 is fully expanded after riveting, the arc edge of the thrust support area 2014 is fully filled, and there is no gap between the pole 3 and the riveted block 2, thereby ensuring the overall riveting strength of the cell cover plate assembly, so that its mechanical strength meets the design requirements, and its thrust resistance performance meets the requirements, thereby ensuring the reliability and safety of the battery cell. At the same time, there is no gap between the pole 3 and the riveted block 2, which can ensure the welding quality between the pole 3 and the riveted block 2, further improving the reliability and safety of the battery.

[0085] At the same time, the present invention provides a calculation formula for the material expansion compensation height h1: This formula can be used to calculate the expansion compensation height h1, so that a reasonable expansion compensation height can be designed for the pole 3. This can not only compensate for the expansion volume of the arc edge of the pole 3, but also prevent the expansion compensation height from being too large, causing excessive expansion of the straight edge of the pole 3 and local deformation of the rivet block 2. It ensures that the rivet block 2 and the external insulating parts can be assembled normally, and realizes precise control of the expansion volume of the pole 3 during the riveting process, which helps to ensure production consistency and reduce the defective product rate.

[0086] In some embodiments, the following conditions are also met:

[0087] 20mm 2 ≤S1≤180mm 2 ,

[0088] 25mm 2 ≤S2≤250mm 2 ,

[0089] 0.55mm≤h2≤1.65mm.

[0090] In this embodiment, by limiting the cross-sectional area S1 of the pole body 301 to 20 mm 2 Up to 180mm 2 The projected area S2 of the thrust bearing area 2014 is limited to 25 mm 2 Up to 250mm 2 Within this range, it can ensure that the pressure generated during the riveting process is evenly distributed, which can effectively avoid weak riveting due to a small area, and prevent material waste or processing difficulties caused by an excessively large area.

[0091] By limiting the depth h2 of the riveted hole section 2012 along the Z direction to within the range of 0.55 mm to 1.65 mm, it helps to control the stress concentration phenomenon during the riveting process. The depth within the appropriate range can ensure the stability of the riveted structure and reduce the risk of fracture due to excessive stress.

[0092] By properly matching the parameter ranges of S1, S2, and h2, the overall reliability of the riveted structure can be significantly improved. Specifically, the coordination of S1 and S2 can form a good support and constraint relationship in the XY plane and Z direction, thereby improving the impact resistance and durability of the connection between the riveted block 2 and the pole 3.

[0093] Furthermore, specific values ​​can be adjusted based on actual needs to accommodate different product specifications and usage environments. For example, a larger value can be selected for high-load conditions, while a smaller value can be used for lightweight designs.

[0094] Specifically, the values ​​of S1 include: 20mm 2 , 40mm2 , 60mm 2 , 80mm 2 , 100mm 2 , 120mm 2 , 140mm 2 , 160mm 2 , 180mm 2 .

[0095] The values ​​of S2 include: 25mm 2 , 30mm 2 , 40mm 2 , 50mm 2 , 60mm 2 , 80mm 2 , 100mm 2 , 120mm 2 , 140mm 2 , 160mm 2 , 180mm 2 , 200mm 2 , 220mm 2 , 250mm 2 .

[0096] The values ​​of h include: 0.55mm, 0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.5mm, 1.6mm, and 1.65mm.

[0097] In some embodiments, the following conditions are also met:

[0098] 5mm 3 ≤V0≤35mm 3 .

[0099] In this embodiment, by limiting the volume V0 of the rivet groove 30123 to 5mm 3 to 35mm 3 Within the range, it can be ensured that the pole body 301 is fully expanded during the riveting process, thereby improving the riveting quality.

[0100] Specifically, the values ​​of V0 include: 5mm 3 , 7mm 3 , 10mm 3 , 13mm 3 , 15mm 3 , 18mm 3 , 20mm 3 , 23mm 3 , 25mm 3 , 28mm 3 , 30mm 3 , 32mm 3 , 35mm3 .

[0101] In some embodiments, the following conditions are also met:

[0102]

[0103] 0.85mm≤h3≤2.5mm,

[0104] 1.5mm≤T≤3.5mm,

[0105] in,

[0106] h3 is the depth of the assembly hole section 2011 along the Z direction, in mm.

[0107] T is the total thickness of the riveting block 2 along the Z direction, in mm.

[0108] In this embodiment, by limiting the depth h3 of the assembly hole section 2011 along the Z direction to within the range of 0.85 mm to 2.5 mm, and limiting the total thickness T of the rivet block 2 to within the range of 1.5 mm to 3.5 mm, and ensuring that the ratio of h3 to T is maintained between 0.45 and 0.75, the structural strength of the pole mounting hole 201 of the rivet block 2 can be ensured. At the same time, when T is determined, if h3 is too large, h2 will be too small, thereby reducing the volume of the thrust support area 2014 and affecting the expansion volume of the pole 3; if h3 is too small, h2 will be too large, thereby increasing the volume of the thrust support area 2014, which will also affect the expansion volume of the pole 3. Therefore, by reasonably limiting the range of h3, T and the ratio thereof, the expansion effect of the pole 3 can be ensured, the fit between the rivet block 2 and the pole 3 can be ensured to be tighter, which helps the rivet block 2 and the pole 3 to form a stable riveted structure, thereby improving the reliability of the overall connection.

[0109] Specifically, the values ​​of h3 include: 0.85mm, 0.9mm, 0.95mm, 1.0mm, 1.2mm, 1.5mm, 1.8mm, 2.0mm, 2.2mm, and 2.5mm.

[0110] The values ​​of T include: 1.5mm, 1.8mm, 2.0mm, 2.2mm, 2.5mm, 2.8mm, 3.0mm, 3.2mm, and 3.5mm.

[0111] In some embodiments, the following conditions are also met:

[0112]

[0113] Wherein, W is the width of the thrust bearing area 2014 along the XY plane, in mm.

[0114] h3 is the depth of the assembly hole section 2011 along the Z direction, in mm.

[0115] In this embodiment, by limiting the ratio of the width W of the thrust support area 2014 to the depth of the assembly hole section 2011 along the Z direction within the range of 0.35 to 1.65, the structural strength of the rivet block 2 in the thrust support area 2014 can be ensured, and the rivet block 2 can be prevented from being deformed under the action of the riveting force, thereby ensuring the riveting effect between the rivet block 2 and the pole 3, forming a tightly fitting, stable and reliable riveted structure, and improving the overall reliability of the battery cover assembly.

[0116] In some embodiments, the error of h1 is between -0.1 mm and +0.1 mm.

[0117] The material expansion compensation height h1 is within the allowable range of processing errors in this field.

[0118] Furthermore, this embodiment further limits the allowable processing error of h1 to between -0.1mm and +0.1mm, that is, after the expansion compensation height of the pole 3 is calculated by the above formula, the expansion compensation height of the pole 3 actually processed is h1±0.1mm. Within this range, it can be ensured that the expansion compensation height of the pole 3 is not too small, resulting in insufficient expansion of the pole 3 and affecting the thrust resistance performance of the pole 3, nor is it too large, resulting in excessive expansion of the pole 3 and causing local deformation of the rivet block 2.

[0119] In some embodiments, the side wall of the riveting hole section 2012 is parallel to the central axis of the pole mounting hole 201 , and the riveting hole section 2012 is connected to the assembly hole section 2011 via an annular step surface.

[0120] In this embodiment, the side wall of the riveting hole section 2012 is parallel to the central axis of the pole mounting hole 201, and the step surface is perpendicular to the central axis of the pole mounting hole 201, that is, the riveting hole section 2012 is a straight-walled hole, and a straight rivet structure is adopted between the riveting block 2 and the pole 3.

[0121] In some embodiments, the pole mounting hole 201 also includes a welding sink 2013 provided on the top of the riveted hole section 2012. Along the X direction and along the Y direction, the size of the welding sink 2013 is larger than the size of the riveted hole section 2012, and the top surface of the riveted column section 30122 is lower than the welding sink 2013.

[0122] In this embodiment, the welding sink 2013 is provided to accommodate the welding mark of the electrode 3 and the riveted block 2 after riveting, ensuring that the welding mark does not protrude from the surface of the riveted block 2, thereby ensuring the overall high dimensional accuracy of the battery cell.

[0123] In some embodiments, the rivet groove 30123 is a tapered hole, and the diameter of the rivet groove 30123 decreases along the riveting direction.

[0124] In this embodiment, since the rivet groove 30123 is conical and the diameter decreases along the riveting direction, the corresponding riveting punch is also a conical cylindrical structure. In this way, there is a larger contact area between the riveting punch and the pole 3, which can guide the volume flow of the pole 3 during the riveting process, further improving the expansion effect of the arc edge of the elliptical pole, so that it can more fully fill the thrust support area 2014.

[0125] Specifically, the structure of the rivet groove 30123 is determined by the rivet punch. Therefore, after the structure and volume of the rivet groove 30123 are determined, the structure and size of the rivet punch are designed accordingly.

[0126] In order to verify the technical solution and technical effects of the present invention, specific experimental cases of battery cover assemblies are provided below, which are specific embodiments and comparative examples respectively. Each case is subjected to thrust testing, welding quality inspection of the pole 3 and the rivet block 2, and appearance inspection of the pole 3 and the rivet block 2 after riveting.

[0127] First, the thrust test is performed using methods known to those skilled in the art. As an example, the thrust test is as follows:

[0128] The testing equipment is a universal material testing machine.

[0129] Test method:

[0130] Randomly select test samples of cell cover assemblies that meet the specifications to ensure that the sample surface is clean and free of scratches or pre-damage.

[0131] Calibrate the force and displacement sensors of the testing machine to ensure data accuracy.

[0132] Place the sampled cell cover assembly in the fixture of the testing machine to ensure that the force point is consistent with the designed position and that the cell cover assembly does not move or tilt during the test.

[0133] Confirm that the fixture is firmly installed, set the loading pressure, and apply thrust to the battery cover assembly along the Z direction, with the thrust directed towards pole 3, and load pole 3 vertically. Set the pressure loading speed.

[0134] Start the tester and apply a thrust to the terminal 3 until the cell cover assembly fails (e.g., the cell cover assembly deforms, or the terminal 3 falls off). The tester records the applied force in real time. The thrust before the cell cover assembly fails is the maximum thrust the cell cover assembly can withstand. Record the maximum thrust value, denoted as F, in Newtons.

[0135] Second, the welding quality of the pole 3 and the riveted block 2 is inspected. Specifically, the welding quality is inspected to see if there is any cold welding, i.e., the welding is not firm, the contact is poor, or there are holes. Inspection methods known to those skilled in the art can be used. For example, the following inspection 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] Third, the appearance inspection of riveting and welding includes checking whether there is obvious deformation or gap in the appearance of each component in the battery cover assembly, and whether the size is qualified.

[0141] The test result requires that the thrust F>1500N is qualified. After riveting, the riveted block 2 has no deformation or warping, there is no gap between the riveted block 2 and the terminal 3, and there is no hot spot or cold weld in the welding.

[0142] The test results are detailed in Tables 1 to 4.

[0143] Table 1

[0144]

[0145] Table 2

[0146]

[0147] By comparing Table 1 and Table 2, it can be seen that in Examples 1 to 6, the height of the pole body 301 is compensated, and the expansion compensation height h1 is designed, and This calculation formula yields h1. Actual measurements show that the thrust resistance of the cell cover assembly meets all requirements. After riveting, there is no gap between the pole 3 and the riveted block 2, indicating good weld quality. The riveted block 2 exhibits no appearance issues such as deformation or bulging.

[0148] In Comparative Examples 1 through 6, h1 is set to 0 mm. This means that no compensation is made for the height of the pole body 301. The pole body 301 and the rivet block 2 are still riveted together using the related art. This means that the top surface of the pole body 301 is flush with the top surface of the rivet hole section 2012 of the rivet block 2. Field measurements show that the pole 3 has insufficient material expansion, resulting in unsatisfactory thrust resistance. Furthermore, the gap between the pole 3 and the rivet block 2 is large, leading to cold welds during welding quality testing, which does not meet requirements.

[0149] Table 3

[0150]

[0151] By comparing Table 1 and Table 3, it can be seen that in Comparative Examples 7 to 12, the difference between the value of h1 and the standard value calculated by the formula is greater than 0.1mm, and the processing error of h1 is too large, exceeding the lower limit of the error of h1, resulting in the expansion compensation height of the pole body 301 being too small. Compared with the case of h1=0mm, the expansion of the pole 3 has improved, but there is still a gap between the pole 3 and the rivet block 2, and the expansion is insufficient, resulting in failure of the thrust test and failure of the welding quality test. There are welding quality problems such as cold welding and exploded points between the rivet block 2 and the pole 3, which do not meet the requirements.

[0152] Table 4

[0153]

[0154] By comparing Table 1 and Table 4, it can be seen that in Comparative Examples 13 to 18, the difference between the value of h1 and the standard value calculated by the formula is greater than 0.1 mm. The processing error of h1 is too large, exceeding the upper limit of the error of h1, resulting in the expansion compensation height of the pole body 301 being too large. After actual measurement, the thrust test is qualified, but the pole 3 expands too much, resulting in serious local deformation of the riveted block 2.

[0155] In some embodiments, a first insulating member 4 and a second insulating member 5 are further included. The first surface of the cover plate 1 and the rivet 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 assembly further includes an explosion-proof valve 7 and an explosion-proof valve patch 8. The cover 1 is provided with an explosion-proof valve mounting hole, within which the explosion-proof valve 7 is disposed. The explosion-proof valve patch 8 is affixed to the upper surface of the explosion-proof valve mounting hole to protect the explosion-proof valve 7. The explosion-proof valve 7 is designed to rapidly explode and release pressure in the event of thermal runaway in the battery cell, thereby ensuring battery safety.

[0158] In some embodiments, the battery cell cover plate assembly also includes a sealing ring 6, which is sleeved on the first pole segment 3011, and at least a portion of the sealing ring 6 is disposed between the first pole segment 3011 and the assembly hole 101 of the cover plate 1, and at least a portion of the sealing ring 6 is disposed between the pole base plate 302 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.

[0159] According to an embodiment of the present invention, in a second aspect, a battery cell is provided, comprising a housing, a pole group, and the cell cover assembly of the above embodiment. The housing has a receiving cavity and an opening communicating with the receiving cavity; the pole group is disposed in the receiving cavity of the housing; and the cell cover assembly is disposed in the opening of the housing, encapsulating the pole group within the housing.

[0160] 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 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 constitutes a vital component of the battery cell and ensures the durability and safety of the battery cell during use.

[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, the riveting block is a rectangular structure, the riveting block is provided with a pole mounting hole, the pole mounting hole is a stepped hole, including an assembly hole section and a riveting hole section, and the assembly hole section and the riveting hole section are both runway-shaped holes; The pole, before riveting, comprises a pole body, the pole body comprising a first pole segment cooperating with the assembly hole and a second pole segment cooperating with and riveted to the pole mounting hole, the pole body being sequentially passed through the assembly hole and the pole mounting hole, the top surface of the second pole segment being higher than the top surface of the riveted hole segment, an annular gap being provided between the second pole segment and the riveted hole segment to form a thrust bearing area, the pole body being riveted with the riveted block, the second pole segment after riveting forming an assembly column segment cooperating with the assembly hole segment and a riveted column segment cooperating with the riveted hole segment, the riveted column segment filling the thrust bearing area, and the top of the riveted column segment being formed with a concave rivet groove by the riveting force; The following conditions are met between the pole and the riveting block: in, h1 is the height of the top surface of the second pole segment above the top surface of the riveting hole segment along the Z direction before riveting, in mm; S1 is the cross-sectional area of ​​the second pole segment along the XY plane before riveting, in mm 2 ; S2 is the projected area of ​​the thrust bearing zone along the Z direction, in mm 2 ; h2 is the depth of the riveting hole segment along the Z direction, in mm; V0 is the volume of the riveting groove, in mm3.

2. The battery cover assembly according to claim 1, characterized in that: Also meets: 20mm 2 ≤S1≤180mm 2 , 25mm 2 ≤S2≤250mm 2 , 0.55mm≤h2≤1.65mm.

3. The battery cover assembly according to claim 1 or 2, characterized in that: Also meets: 5mm 3 ≤V0≤35mm 3 。 4. The battery cover assembly according to claim 1 or 2, characterized in that: Also meets: 0.85mm≤h3≤2.5mm, 1.5mm≤T≤3.5mm, in, h3 is the depth of the assembly hole section along the Z direction, in mm, T is the total thickness of the riveting block along the Z direction, in mm.

5. The battery cover assembly according to claim 1 or 2, characterized in that: Also meets: Wherein, W is the width of the thrust bearing area along the XY plane, in mm. h3 is the depth of the assembly hole segment along the Z direction, in mm.

6. The battery cover assembly according to claim 1 or 2, characterized in that: It also satisfies the following requirements: the error of h1 is between -0.1mm and +0.1mm.

7. The battery cover assembly according to claim 1 or 2, characterized in that: The side wall of the riveting hole section is parallel to the central axis of the pole mounting hole, and the riveting hole section is connected to the assembly hole section via an annular step surface.

8. The battery cover assembly according to claim 1 or 2, characterized in that: The pole mounting hole further includes a welding sinker provided on the top of the riveted hole section. The size of the welding sinker is larger than that of the riveted hole section along the X direction and the Y direction, and the top surface of the riveted column section is lower than the welding sinker.

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.

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