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, and the assembling hole section and the riveting hole section are both circular holes; the terminal post before riveting comprises a first terminal post section, the top surface of the first terminal post section is higher than the top surface of a riveting hole section, a thrust bearing area is arranged between the first terminal post section and the riveting hole section, the first terminal post section after riveting forms an assembly post section and a riveting post section, the riveting post section fills the thrust bearing area, and the riveting hole section is arranged between the assembly post section and the riveting post section. A concave riveting punched hole 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 pole is riveted, no gap exists between the pole and the riveting block, and the integral riveting strength of the battery cell cover plate assembly is ensured, so that the thrust resistance meets the requirement, 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 assembly includes a cover, a pole and a rivet block. Among them, the pole is the key part for connecting to the external circuit, while the cover plays a role of sealing and protection. During the assembly process, the pole and the cover 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 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 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).

[0004] For circular poles, there are differences in the expansion of poles with different rod diameters, and the battery cover assembly in the related art adopts a method in which the top surface of the pole is flush with the top surface of the rivet hole section of the rivet hole, resulting in insufficient expansion of the pole. Insufficient expansion of the pole will cause a gap between the pole and the rivet block, resulting in insufficient riveting strength of the battery cover assembly and poor thrust resistance. Summary of the Invention

[0005] In view of this, the present invention provides a battery cover assembly, a battery cell and a battery pack to solve the problem of different material expansion of poles with different rod diameters.

[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 the assembly hole section and the rivet hole section are both circular holes; the pole before riveting includes a first pole section, the first pole section is sequentially passed through the assembly hole and the pole mounting hole, the top surface of the first pole section is higher than the top surface of the rivet hole section, the diameter of the first pole section matches the inner diameter of the assembly hole section, and there is an annular gap between the first pole section and the rivet hole section to form a thrust bearing area, the first pole section is riveted with the rivet block, and the first pole section after riveting includes an assembly column section matched with the assembly hole section and a rivet column section matched 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 punching by the riveting force; the pole and the rivet block meet the following requirements:

[0007]

[0008] in,

[0009] h1 is the height of the top surface of the first pole segment above the top surface of the riveting hole segment along the Z direction, in mm;

[0010] h2 is the depth of the riveting hole section along the Z direction, in mm;

[0011] D is the inner diameter of the riveted hole section, in mm;

[0012] d is the diameter of the first pole segment, in mm;

[0013] V0 is the volume of the riveting punching hole, in mm 3 .

[0014] Beneficial Effects: The battery cell cover assembly provided by the present invention, by increasing the volume of the expansion deformation section of the pole and adding the expansion compensation height h1, can compensate for the expansion of the pole during the riveting process, solving the problem of different expansions of poles with different rod diameters. It ensures that, regardless of the pole diameter, after riveting, the pole can be fully expanded, 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, 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.

[0015] 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. The preset expansion compensation volume is designed according to the pole rod diameter, so that a reasonable expansion compensation height can be designed for the pole. This can not only compensate for the expansion volume of the pole, but also prevent the expansion compensation height from being too large, causing the pole to over-expand and cause local deformation of the rivet block. This ensures that the rivet block and external insulation parts can be assembled normally, and realizes precise control of the pole expansion volume during the riveting process, which helps to ensure production consistency and reduce the defective product rate.

[0016] In an optional embodiment, the following conditions are also met:

[0017] 3.5mm≤d≤20mm,

[0018] 4.0mm≤D≤21.5mm,

[0019]

[0020] In an optional embodiment, the following conditions are also met:

[0021] 0.65mm≤h2≤1.85mm.

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

[0023] 0.5mm 3 ≤V0≤20mm 3 .

[0024] In an optional embodiment, the following conditions are also met:

[0025] 0.8mm≤h3≤2.0mm,

[0026] Wherein, h3 is the depth of the assembly hole segment along the Z direction, in mm.

[0027] In an optional embodiment, the following conditions are also met:

[0028]

[0029] In an optional embodiment, it is also satisfied that the error of h1 is between -0.08 mm and +0.08 mm.

[0030] 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.

[0031] 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.

[0032] Beneficial Effects: The cell cover assembly is applied to the battery cell to seal the opening of the cell housing, sealing and protecting the internal components of the battery, preventing chemical leakage and the impact of the external environment on the battery. The poles of the cell cover assembly provide a path for the flow of current in and out, ensuring the current conduction during the battery cell's charging and discharging process. The cell cover assembly not only serves as an electrical connection for the battery cell, but also enhances the overall structural stability of the battery cell. It is an important component of the battery cell, ensuring the durability and safety of the battery cell during use.

[0033] 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.

[0034] 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.

[0035] 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

[0036] 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.

[0037] 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;

[0038] Figure 2 for Figure 1 The cross-sectional view of the riveting block shown is along the axial direction of the pole mounting hole;

[0039] Figure 3 This is a schematic structural diagram of a pole in a battery cover assembly before riveting according to an embodiment of the present invention;

[0040] Figure 4 for Figure 3 A cross-sectional view of the pole shown along its axial direction;

[0041] Figure 5 for Figure 3 The schematic diagram of the structure of the pole after riveting is shown;

[0042] Figure 6 This is a structural schematic diagram of a battery cell cover assembly according to an embodiment of the present invention;

[0043] Figure 7 for Figure 6 A top view of the cell cover assembly shown;

[0044] Figure 8 for Figure 6 The cell cover assembly shown is at the front edge of the pole riveting Figure 7 Cross-sectional view at AA in the middle;

[0045] Figure 9 for Figure 8 A partial enlarged view of point C in the middle;

[0046] Figure 10 for Figure 6 The battery cover assembly shown is at the rear edge of the pole riveting Figure 7 Cross-sectional view at AA in the middle;

[0047] Figure 11 for Figure 10 A partial enlarged view of point D in the middle;

[0048] Figure 12 for Figure 6 The battery cover assembly shown is at the rear edge of the pole riveting Figure 7 Cross-sectional view at the middle BB;

[0049] Figure 13 for Figure 6 An exploded view of the cell cover assembly is shown.

[0050] Description of reference numerals:

[0051] 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 bearing area; 3. Pole; 301. First pole section; 3011. Assembly column section; 3012. Riveted column section; 3013. Riveted punching hole; 302. Pole bottom plate; 303. Second pole section; 4. First insulating member; 5. Second insulating member; 6. Sealing ring; 7. Explosion-proof valve; 8. Explosion-proof valve patch. DETAILED DESCRIPTION

[0052] 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.

[0053] The following combination Figures 1 to 13 , describing embodiments of the present invention.

[0054] 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 circular holes. The pole 3 before riveting comprises a first pole section 301, which is sequentially passed through the assembly hole 101 and the pole mounting hole 201. The top surface of the first pole section 301 is higher than the top surface of the rivet hole section 2012. The diameter of the first pole section 301 is the same as that of the assembly hole section 2011. 011, an annular gap is provided between the first pole segment 301 and the riveting hole segment 2012 to form a thrust support area 2014, the first pole segment 301 is riveted to the riveting block 2, and the riveted first pole segment 301 includes an assembly column segment 3011 that cooperates with the assembly hole segment 2011 and a riveted column segment 3012 that cooperates with the riveted hole segment 2012. The riveted column segment 3012 fills the thrust support area 2014, and a concave riveting punching 3013 is formed on the top of the riveted column segment 3012 by the riveting force; the following conditions are met between the pole 3 and the riveting block 2:

[0055]

[0056] in,

[0057] h1 is the height of the top surface of the first pole segment 301 above the top surface of the riveting hole segment 2012 along the Z direction, in mm;

[0058] h2 is the depth of the riveting hole section 2012 along the Z direction, in mm;

[0059] D is the inner diameter of the riveting hole section 2012, in mm;

[0060] d is the diameter of the first pole segment 301, in mm;

[0061] V0 is the volume of the riveted punch 3013, in mm 3 .

[0062] 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. The pole mounting hole 201 of the rivet block 2 is set as a circular 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.

[0063] Specifically, V0 is the volume of the riveted punching hole 3013, which is a blind hole. The volume V0 of the riveted punching hole 3013 is as follows: Figure 11 The volume of the area indicated by the black shaded block.

[0064] In this embodiment, both the assembly hole section 2011 and the rivet hole section 2012 are circular holes. That is, the sidewalls of the rivet hole section 2012 are parallel to the central axis of the pole mounting hole 201. The rivet hole section 2012 is a straight-walled hole, connected to the assembly hole section 2011 by an annular stepped surface. A straight rivet structure is employed between the rivet block 2 and the pole 3.

[0065] 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: Figure 3 and Figure 4 As shown, the diameter d of the first pole section 301 is commonly known as the rod diameter of the pole 3. The structure of the pole 3 after riveting is as follows Figure 5 As shown, the first pole segment 301 after riveting includes an assembly column segment 3011 that cooperates with the assembly hole segment 2011 and a riveted column segment 3012 that cooperates with the riveted hole segment 2012. The riveted column segment 3012 fills the thrust support area 2014, and the top of the riveted column segment 3012 is formed with a concave riveted punching hole 3013 due to the riveting force.

[0066] An annular gap exists between the first pole segment 301 and the rivet hole segment 2012, which constitutes a thrust support area 2014. During the riveting process between the pole 3 and the rivet block 2, the upper end of the first pole segment 301 expands and deforms toward the thrust support area 2014 under the action of the riveting force until the entire thrust support area 2014 is filled. The undeformed portion of the first pole segment 301 still mates with the assembly hole segment 2011 of the pole mounting hole 201 and the assembly hole 101 of the cover plate, forming the assembly column segment 3011. The expanded and deformed portion mates with the rivet hole segment 2012 of the pole mounting hole 201, forming the riveted column segment 3012. The thrust support area 2014 is used to accommodate the expanded portion of the pole 3 to form the riveted column segment 3012, thereby achieving a connection between the cover plate 1, the rivet 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 3012 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.

[0067] Reference Figure 9 The section from the top of the first pole segment 301 to the bottom of the thrust support area 2014 is the expansion and deformation section of the pole 3. This section 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 referred to as the expansion compensation height.

[0068] Based on the principle of equal volume flow in material expansion theory, in related art cell cover plate assemblies, the top surface of the first terminal segment is typically flush with the top surface of the rivet hole segment of the rivet block, without considering the differences in material expansion for terminals of different rod diameters. In particular, the larger the terminal diameter, the more difficult it is to rivet and expand the material, the more uneven the terminal material flow will be, and the greater the risk of insufficient material expansion.

[0069] In order to solve this technical problem, the present invention provides a cell cover plate assembly, wherein, by increasing the volume of the expansion deformation section of the pole 3 and adding a compensation height h1 for expansion, it is possible to compensate for the insufficient expansion of the pole 3 during the riveting process, solve the problem of insufficient expansion of poles 3 with different rod diameters, ensure that the pole 3 is fully expanded after riveting, 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.

[0070] At the same time, the present invention provides a calculation formula for the material expansion compensation height h1: The expansion compensation height h1 can be calculated by this formula. The preset expansion compensation volume is designed according to the rod diameter of the pole 3, so that a reasonable expansion compensation height can be designed for the pole 3, which can compensate for insufficient expansion of the pole 3 without causing excessive expansion 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.

[0071] In some embodiments, the following conditions are also met:

[0072] 3.5mm≤d≤20mm,

[0073] 4.0mm≤D≤21.5mm,

[0074]

[0075] By limiting the diameter d of the first pole segment 301 to be within the range of 3.5 mm to 20 mm, limiting the inner diameter D of the rivet hole segment 2012 to be within the range of 4.0 mm to 21.5 mm, and limiting the width of the thrust bearing area 2014 along the XY plane Between 0.4mm and 1.0mm, the expansion range of the pole 3 during the riveting process can be further optimized, ensuring that the volume of the expansion is within a reasonable range, avoiding the problem of insufficient or excessive expansion, and making the pole 3 and the rivet block 2 fit tightly and riveted firmly, thereby enhancing the stability and reliability of the overall structure of the battery cover assembly.

[0076] Furthermore, these parameters allow for adjustment of specific values ​​based on actual needs to accommodate different product specifications and usage environments. For example, a larger value may be chosen for high-load conditions, while a smaller value may be used for lightweight designs.

[0077] Specifically, the values ​​of d include: 3.5mm, 4mm, 5mm, 8mm, 10mm, 12mm, 15mm, 18mm, and 20mm.

[0078] The values ​​of D include: 4mm, 5mm, 8mm, 9mm, 10mm, 12mm, 15mm, 18mm, 20mm, 21mm, and 21.5mm.

[0079] In some embodiments, the following conditions are also met:

[0080] 0.65mm≤h2≤1.85mm.

[0081] By limiting the depth h2 of the riveted hole section 2012 along the Z direction to within the range of 0.65 mm to 1.85 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.

[0082] Specifically, the values ​​of h2 include: 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 1.0mm, 1.2mm, 1.5mm, 1.8mm, and 1.85mm.

[0083] In some embodiments, the following conditions are also met:

[0084] 0.5mm 3 ≤V0≤20mm 3 .

[0085] In this embodiment, by limiting the volume V0 of the riveting punching hole 3013 to 0.5mm 3 Up to 20mm 3 Within the range, it can be further ensured that the first pole segment 301 is fully expanded during the riveting process, thereby improving the riveting quality.

[0086] Specifically, the values ​​of V0 include: 0.5mm 3 , 1mm 3 , 2mm 3, 5mm 3 , 8mm 3 , 10mm 3 , 12mm 3 , 15mm 3 , 18mm 3 , 20mm 3 .

[0087] Preferably, the value of V0 varies with the value of d. The larger d is, the larger V0 is.

[0088] In some embodiments, the following conditions are also met:

[0089] 0.8mm≤h3≤2.0mm,

[0090] Wherein, h3 is the depth of the assembly hole segment along the Z direction, in mm.

[0091] In this embodiment, by limiting the depth h3 of the assembly hole section 2011 along the Z direction to within the range of 0.8 mm to 2.0 mm, the structural strength of the pole mounting hole 201 of the riveting block 2 can be ensured; at the same time, when the thickness of the riveting block 2 is determined, if h3 is too large, h2 will be too small, reducing the volume of the thrust support area 2014 and affecting the expansion volume of the pole 3; and if h3 is too small, h2 will be too large, 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 value range of h3, the expansion effect of the pole 3 can be further ensured, and the fit between the riveting block 2 and the pole 3 can be ensured to be closer, which helps the riveting block 2 and the pole 3 to form a stable riveted structure, thereby improving the reliability of the overall connection.

[0092] Specifically, the values ​​of h3 include: 0.8mm, 0.9mm, 0.95mm, 1.0mm, 1.2mm, 1.5mm, 1.8mm, and 2.0mm.

[0093] In some embodiments, the following conditions are also met:

[0094]

[0095] In this embodiment, by defining The range of the thrust support area 2014 and the ratio of the depth of the assembly hole section 2011 along the Z direction are standardized, which can ensure the structural strength of the rivet block 2 in the thrust support area 2014, prevent the rivet block 2 from being deformed under the action of the riveting force, ensure the riveting effect between the rivet block 2 and the pole 3, form a tightly matched, stable and reliable riveted structure, and improve the overall reliability of the battery cover assembly.

[0096] In some embodiments, the error of h1 is between -0.08 mm and +0.08 mm.

[0097] The material expansion compensation height h1 is within the allowable range of processing errors in this field.

[0098] Furthermore, this embodiment limits the allowable processing error of h1 to between -0.08mm and +0.08mm, 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±0.08mm. 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.

[0099] 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 3012 is lower than the welding sink 2013.

[0100] 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.

[0101] In some embodiments, the riveting punching hole 3013 is a tapered hole, and the diameter of the riveting punching hole 3013 decreases along the riveting direction.

[0102] In this embodiment, since the riveting punch 3013 is conical and its diameter decreases along the riveting direction, the corresponding riveting needle is also a conical column structure. In this way, there is a larger contact area between the riveting needle 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 pole 3, so that it can more fully fill the thrust support area 2014.

[0103] Specifically, the structure of the riveting punch 3013 is determined by the riveting punch pin. Therefore, after the structure and volume of the riveting punch 3013 are determined, the structure and size of the riveting punch pin are designed accordingly.

[0104] In order to verify the technical solution and technical effects of the present invention, specific experimental cases of battery cell cover plate assemblies are provided below, including embodiments and comparative examples. Thrust tests, welding quality inspections of the pole 3 and the rivet block 2, and appearance inspections of the pole 3 and the rivet block 2 after riveting are performed on each case.

[0105] First, the thrust test is performed using methods known to those skilled in the art. As an example, the thrust test is as follows:

[0106] The testing equipment is a universal material testing machine.

[0107] Test method:

[0108] 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.

[0109] Calibrate the force and displacement sensors of the testing machine to ensure data accuracy.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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:

[0114] 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).

[0115] 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.

[0116] 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.

[0117] Here, method 1 is used to test the welding quality of each case.

[0118] 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.

[0119] 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.

[0120] The test results are detailed in Tables 1 to 4.

[0121] Table 1

[0122]

[0123] Table 2

[0124]

[0125] By comparing Table 1 and Table 2, it can be seen that in Examples 1 to 5, the height of the first pole segment 301 is compensated, and the expansion compensation height h1 is designed, and the expansion compensation height h2 is calculated. 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.

[0126] In Comparative Examples 1 through 5, h1 is set to 0 mm. This means that the height of the first pole segment 301 is not compensated, and the first pole segment 301 is still riveted to the rivet block 2 using the related art. This means that the top surface of the first pole segment 301 is flush with the top surface of the rivet hole 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, resulting in cold welds during welding quality testing, which does not meet requirements.

[0127] Table 3

[0128]

[0129] By comparing Table 1 and Table 3, it can be seen that in Comparative Examples 6 to 10, the absolute value of the difference between the value of h1 and the standard value calculated by the formula is greater than 0.08mm, 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 first pole segment 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.

[0130] Table 4

[0131]

[0132] By comparing Table 1 and Table 4, it can be seen that in Comparative Examples 11 to 15, the difference between the value of h1 and the standard value calculated by the formula is greater than 0.08 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 first pole segment 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.

[0133] 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 .

[0134] 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.

[0135] The battery cover assembly also includes an explosion-proof valve 7 and an explosion-proof valve patch 8. The cover 1 has an explosion-proof valve mounting hole, in which the explosion-proof valve 7 is located. The explosion-proof valve patch 8 is attached 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 quickly explode and release pressure in the event of thermal runaway in the battery cell, thereby ensuring the safety of the battery.

[0136] In some embodiments, the electrode 3 further includes a second electrode segment 303, which is connected to the electrode base plate 302 and mates with the assembly hole 101 of the cover plate 1. The battery cell cover plate assembly further includes a sealing ring 6, which is sleeved on the second electrode segment 303. At least a portion of the sealing ring 6 is disposed between the second electrode segment 303 and the assembly hole 101 of the cover plate 1, and at least a portion of the sealing ring 6 is disposed between the electrode base plate 302 and the cover plate 1. In this way, the sealing ring 6 can form a seal between the electrode 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.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] Because the battery pack includes battery cells and has all the technical effects of battery cells, they will not be described here.

[0142] 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 circular holes; The pole, before riveting, comprises a first pole segment, the first pole segment being sequentially inserted into the assembly hole and the pole mounting hole, the top surface of the first pole segment being higher than the top surface of the riveted hole segment, the diameter of the first pole segment being matched with the inner diameter of the assembly hole segment, an annular gap being provided between the first pole segment and the riveted hole segment to form a thrust bearing area, the first pole segment being riveted to the riveted block, and the first pole segment after riveting comprising an assembly column segment matched with the assembly hole segment and a riveted column segment matched with the riveted hole segment, the riveted column segment filling the thrust bearing area, and a concave riveted punching hole being formed on the top of the riveted column segment 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 first pole segment above the top surface of the riveting hole segment along the Z direction, in mm; h2 is the depth of the riveting hole segment along the Z direction, in mm; D is the inner diameter of the riveting hole section, in mm; d is the diameter of the first pole segment, in mm; V0 is the volume of the riveting punching hole, in mm 3 .

2. The battery cover assembly according to claim 1, characterized in that: Also meets: 3.5mm≤d≤20mm, 4.0mm≤D≤21.5mm, 3. The battery cover assembly according to claim 1 or 2, characterized in that: Also meets: 0.65mm≤h2≤1.85mm.

4. The battery cover assembly according to claim 1 or 2, characterized in that: Also meets: 0.5mm 3 ≤V0≤20mm 3 。 5. The battery cover assembly according to claim 1 or 2, characterized in that: Also meets: 0.8mm≤h3≤2.0mm, Wherein, h3 is the depth of the assembly hole segment along the Z direction, in mm.

6. The battery cover assembly according to claim 5, characterized in that: Also meets:

7. The battery cover assembly according to claim 1 or 2, characterized in that: It also satisfies that the error of h1 is between -0.08mm and +0.08mm.

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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