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 body, a riveting block and a pole, the cover plate body is provided with an assembly hole; the riveting block is provided with a pole mounting hole, and the pole mounting hole is a stepped hole and comprises a first hole section and a second hole section; the post terminal before riveting comprises a post terminal body, an annular gap between the post terminal body and the second hole section forms a riveting filling area, the volume of the riveting filling area is V2, the post terminal body is riveted with the riveting block, and the post terminal body after riveting comprises a first post section matched with the first hole section and a second post section expanding towards the riveting filling area, a sunken riveting hole is formed in the top of the second column section, the volume V1 of the riveting hole is larger than or equal to 90% and smaller than or equal to 150%, and V1 / V2 is larger than or equal to 90%. According to the invention, sufficient expansion of the pole can be ensured, a gap between the pole and the riveting block is avoided, and the thrust resistance of the battery cell cover plate assembly, the sealing performance of the battery cell and the welding quality between the riveting block and the pole are improved.

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 cell cover assembly consists of a cover, a terminal, and a rivet block. The terminal is a key component for connecting to the external circuit, while the cover provides a seal and protection. During assembly, the terminal and cover are secured together using the rivet block. When riveting the terminal to the rivet block, vertical pressure is applied to the terminal from its central axis, causing the top of the terminal to expand and deform, securing the connection to the rivet block.

[0004] In the existing battery cell cover structure, when the riveting force is applied to the pole, the pole and the rivet block do not expand sufficiently after riveting, resulting in a gap between the pole and the rivet block, which in turn leads to insufficient riveting strength of the cover, the mechanical strength cannot meet the design requirements, and the thrust resistance performance is poor. It also affects the sealing performance of the battery cell, resulting in low 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 problem of poor thrust resistance and poor sealing of the battery cover assembly due to insufficient material expansion after riveting the pole and the rivet block.

[0006] In a first aspect, the present invention provides a battery cell cover assembly, comprising a cover body, a rivet block, and a pole. The cover body is provided with an assembly hole; the rivet block is provided with a pole mounting hole, which is a stepped hole comprising a first hole segment and a second hole segment sequentially arranged in a direction away from the cover body; the pole before riveting comprises a pole body, which passes through the assembly hole and the pole mounting hole in sequence, and the annular gap between the pole body and the second hole segment constitutes a riveted filling area, the volume of which is V2, in mm. 3 The pole body and the rivet block are riveted. After riveting, the pole body includes a first column segment that matches the first hole segment and a second column segment that expands toward the rivet filling area. A concave rivet hole is formed on the top of the second column segment. The volume of the rivet hole is V1, in mm. 3 ;Satisfy 90%≤V1 / V2≤150%.

[0007] Beneficial Effects: The present invention limits the percentage ratio of the volume V1 of the rivet hole 302 to the volume V2 of the rivet filling area, controlling it within the range of 90% to 150%. This ensures that the pole 3 is fully expanded, avoids gaps between the pole and the rivet block, and improves the mechanical strength and thrust resistance of the battery cover assembly, as well as the sealing performance of the battery cell. Furthermore, the tight fit between the pole 3 and the rivet block 2, with no gap between them, significantly improves the welding quality between the pole 3 and the rivet block 2, and enhances the reliability and sealing of the battery.

[0008] In an optional embodiment, the following is also satisfied: 5.5 mm 3 ≤V1≤30mm 3 ; 5mm 3 ≤V2≤30mm 3 .

[0009] In an optional embodiment, along the axial direction of the pole mounting hole, the sum of the depths of the first hole segment and the second hole segment is A, in mm, and the depth of the second hole segment is B, in mm, satisfying: 40%≤B / A≤60%.

[0010] In an optional embodiment, the following conditions are also satisfied: 0.9 mm ≤ B ≤ 1.8 mm; 1.8 mm ≤ A ≤ 3.6 mm.

[0011] In an optional embodiment, a first insulating member is further included, which is arranged between the rivet block and the cover body. The first insulating member is provided with a receiving groove, and the rivet block is arranged in the receiving groove of the first insulating member. The top surface of the rivet block is higher than the top surface of the first insulating member, and the height difference is C, in mm, satisfying: 4%≤C / (A+C)≤20%.

[0012] In an optional embodiment, the following condition is also satisfied: 0.15 mm ≤ C ≤ 0.5 mm.

[0013] In an optional embodiment, after the pole body is riveted, it also includes a third column segment that cooperates with the assembly hole of the cover body, the diameter of the third column segment is larger than the diameter of the first column segment, and the diameter of the second column segment is larger than the diameter of the first column segment; along the length direction of the cover body, the single-sided contact surface width of the second column segment and the riveted block is D, in mm, and the single-sided contact surface width of the third column segment and the riveted block is E, in mm, satisfying: 1≤E / D≤10.

[0014] In an optional embodiment, the following conditions are also satisfied: 0.3 mm ≤ D ≤ 1.5 mm; 0.4 mm ≤ E ≤ 5 mm.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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

[0020] 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.

[0021] Figure 1 This is a structural schematic diagram of a battery cell cover assembly according to an embodiment of the present invention;

[0022] Figure 2 for Figure 1 A top view of the cell cover assembly shown;

[0023] Figure 3 For the Figure 2 Cross-sectional view at FF;

[0024] Figure 4 for Figure 3 A partial enlarged view of point G in the middle;

[0025] Figure 5 for Figure 4 The structure shown is a schematic diagram of the structure before riveting;

[0026] Figure 6 for Figure 3 Schematic diagram of the structure of the middle cover plate body;

[0027] Figure 7 for Figure 3 Schematic diagram of the structure of the middle riveting block;

[0028] Figure 8 for Figure 3 Schematic diagram of the center pole;

[0029] Figure 9 This is a structural schematic diagram of another battery cell cover assembly according to an embodiment of the present invention;

[0030] Figure 10 for Figure 9 A top view of the cell cover assembly shown;

[0031] Figure 11 For the Figure 10 Cross-sectional view at HH in the middle;

[0032] Figure 12 for Figure 11 A partial enlarged view of point I in the middle.

[0033] Description of reference numerals:

[0034] 1. Cover plate body; 101. Assembly hole; 2. Rivet block; 201. Pole mounting hole; 2011. First hole section; 2012. Second hole section; 2013. Welding sink; 3. Pole; 301. Pole body; 3011. First column section; 3012. Second column section; 3013. Third column section; 302. Rivet hole; 303. 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

[0035] 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.

[0036] In the battery cell cover assembly, the pole and the rivet block are riveted together before being welded. During the riveting process, under the action of the riveting force, the top of the pole expands and deforms toward the pole mounting hole of the rivet block, forming a structure that matches the pole mounting hole of the rivet block. The pole and the rivet block are then welded to achieve a fixed connection. However, during the riveting process, the pole often does not expand sufficiently and cannot fill the pole mounting hole of the rivet block, resulting in a gap between the pole and the rivet block, which in turn leads to insufficient riveting strength and poor thrust resistance of the overall battery cell cover assembly. In addition, the gap between the pole and the rivet block will also affect the welding quality of the pole and the rivet block, resulting in welding quality problems such as burn points. If the gap is too large, the pole and the rivet block cannot be welded.

[0037] To this end, the present invention solves the above-mentioned technical problems by limiting the matching structure and parameters of the pole and the riveting block to ensure that the pole expands sufficiently during the riveting process.

[0038] The following combination Figures 1 to 12 , describing embodiments of the present invention.

[0039] According to an embodiment of the present invention, in a first aspect, a cell cover assembly is provided, comprising a cover body 1, a rivet block 2, and a pole 3. The cover body 1 is provided with an assembly hole 101; the rivet block 2 is provided with a pole mounting hole 201, which is a stepped hole comprising a first hole section 2011 and a second hole section 2012 sequentially arranged in a direction away from the cover body 1; the pole 3 before riveting comprises a pole body 301, which passes through the assembly hole 101 and the pole mounting hole 201 in sequence, and the annular gap between the pole body 301 and the second hole section 2012 constitutes a riveted filling area, the volume of which is V2, in units of mm 3 The pole body 301 and the rivet block 2 are riveted together. After riveting, the pole body 301 includes a first column segment 3011 that cooperates with the first hole segment 2011 and a second column segment 3012 that expands toward the rivet filling area. A concave rivet hole 302 is formed at the top of the second column segment 3012. The volume of the rivet hole 302 is V1, in mm. 3 ;Satisfy 90%≤V1 / V2≤150%.

[0040] Specifically, the rivet hole 302 is a blind hole, and the volume V1 of the rivet hole 302 is as follows: Figure 4 The volume of the area shown by the black shaded block in the figure. The volume V2 of the riveted filling area is as follows: Figure 5 The volume of the area indicated by the black shaded block.

[0041] The present invention provides a battery cell cover plate assembly, wherein the structure of the pole 3 changes before and after riveting. There is an annular gap between the pole body 301 and the second hole segment 2012, and the gap constitutes a riveted filling area. During the riveting process of the pole 3 and the riveted block 2, the upper end of the pole body 301 will expand and deform toward the riveted filling area under the action of the riveting force until the entire riveted filling area is filled. At this time, the pole body 301 includes two parts, the undeformed part still cooperates with the first hole segment 2011 of the pole mounting hole 201 to form a first column segment 3011, and the expanded and deformed part is adapted to the second hole segment 2012 of the pole mounting hole 201 to form a second column segment 3012. The riveted filling area is used to support and accommodate the expanded part of the pole 3 so that it forms the second column segment 3012, thereby realizing the riveting of the cover body 1, the riveted block 2 and the pole 3. Specifically, after the pole 3 and the rivet block 2 are riveted together, the second pole section 3012 formed by the expansion of the pole 3 is used to withstand the thrust load on the cell cover assembly in the battery pack, and is a very important structure in the cell cover assembly.

[0042] To address the issue of insufficient material expansion in the terminal 3, the present invention limits the percentage ratio of the volume V1 of the rivet hole 302 to the volume V2 of the rivet filling area, controlling it within the range of 90% to 150%. This ensures that the terminal 3 is fully expanded, avoids gaps between the terminal 3 and the rivet block 2, and improves the mechanical strength and thrust resistance of the battery cover assembly, as well as the sealing performance of the battery cell. At the same time, the tight fit between the terminal 3 and the rivet block 2, with no gaps between them, can significantly improve the welding quality between the terminal 3 and the rivet block 2, and enhance the reliability and sealing of the battery.

[0043] In an embodiment of the present invention, the ratio of the volume V1 of the rivet hole 302 to the volume V2 of the rivet filling area must be greater than 90%, otherwise, the pole 3 will not expand sufficiently, and there will be a gap between the pole 3 and the rivet block 2, resulting in weak riveting strength and poor thrust resistance of the overall battery cover assembly. At the same time, the gap between the two is too large, making welding impossible; at the same time, the ratio of the volume V1 of the rivet hole 302 to the volume V2 of the rivet filling area must be less than 150%, otherwise, the pole 3 will expand excessively. At this time, the riveting strength between the pole 3 and the rivet block 2 is sufficient, and the thrust resistance of the battery cover assembly is good. However, due to excessive expansion of the pole 3, the rivet block 2 and its external insulating parts will be locally deformed, the size will be out of tolerance, and the external insulating parts will be at risk of cracking, affecting the insulation performance of the battery cell.

[0044] In addition, the pole 3 in the cell cover assembly includes an oblong pole and a circular pole. The oblong pole is also commonly known as an elliptical pole, such as Figures 1 to 8As shown, the rivet block 2 adapted therewith has the first hole section 2011 and the second hole section 2012 of the pole mounting hole 201 of the rivet block 2 projected in the axial direction, both of which are waist-shaped holes. Figures 9 to 12 As shown, the matching rivet block 2 has a first hole segment 2011 and a second hole segment 2012, both of which are circular holes, along the axial projection of the pole mounting hole 201 of the rivet block 2. The present invention is applicable to both types of pole 3 structures. That is, for both types of pole 3 structures, ensuring that 90% ≤ V1 / V2 ≤ 150% ensures excellent riveting and welding between the pole 3 and the rivet block 2.

[0045] In some embodiments, the following conditions are also met: 5.5 mm 3 ≤V1≤30mm 3 ; 5mm 3 ≤V2≤30mm 3 .

[0046] The volume V1 of the rivet hole 302 is 5.5 mm 3 Up to 30mm 3 , and the volume V2 of the riveted filling area is 5mm 3 Up to 30mm 3 The present invention is applicable to all pole 3 structures within the range of . That is, within this range, various specifications of cell cover plate assemblies can ensure good riveting and welding effects between the pole 3 and the riveting block 2, as long as they meet 90%≤V1 / V2≤150%.

[0047] In some embodiments, along the axial direction of the pole mounting hole 201 , the sum of the depths of the first hole segment 2011 and the second hole segment 2012 is A, in mm, and the depth of the second hole segment 2012 is B, in mm, satisfying: 40%≤B / A≤60%.

[0048] Specifically, refer to Figure 4 or Figure 12The depth B of the second hole segment 2012, i.e., the depth of the riveted filling area along the axial direction of the pole mounting hole 201, is B. The ratio of the depth B of the second hole segment 2012 to the sum of the depths A of the first and second hole segments 2011, 2012 is controlled within a range of 40% to 60%. The percentage of B / A cannot be lower than 40%, otherwise, the volume of the riveted filling area will be too small, and the riveted contact area between the pole 3 and the riveted block 2 will be small. After the pole 3 and the riveted block 2 are riveted, the thrust resistance of the battery cover assembly is poor, and the pole 3 is at risk of falling off; in addition, the step formed between the first hole segment 2011 and the second hole segment 2012 plays a supporting role in the riveting and material expansion process of the pole 3. Therefore, the percentage of B / A cannot be higher than 60%, otherwise, the depth of the first hole segment 2011 of the riveted block 2 is too small, the structural strength of the lower part of the riveted block 2 is insufficient, the supporting force of the step between the first hole segment 2011 and the second hole segment 2012 is insufficient, and deformation is prone to occur. After the pole 3 and the riveted block 2 are riveted, the thrust resistance of the battery cover assembly is poor, and the riveted block 2 is at risk of falling off.

[0049] Since the pole mounting hole 201 of the rivet block 2 and the assembly hole 101 of the cover body 1 are concentrically arranged, the direction along the axial direction of the pole mounting hole 201 is also the axial direction of the assembly hole 101 of the cover body 1, or the thickness direction of the cover body 1. Figure 2 In FIG, the direction indicated by X is the length direction of the cover body 1, and the direction indicated by Y is the width direction of the cover body 1. Figure 3 or Figure 6 In the figure, the direction indicated by Z is the thickness direction of the cover body 1, which is also the direction in which the riveting force is applied.

[0050] In some embodiments, the following conditions are also satisfied: 0.9 mm ≤ B ≤ 1.8 mm; 1.8 mm ≤ A ≤ 3.6 mm.

[0051] In this embodiment, the depth B of the second hole section 2012 is controlled within the range of 0.9 mm to 1.8 mm, and the sum of the depths A of the first hole section 2011 and the second hole section 2012 is controlled within the range of 1.8 mm to 3.6 mm, which can adapt to 5.5 mm. 3 ≤V1≤30mm 3 and 5mm 3 ≤V2≤30mm 3 Cell cover assemblies in various specifications within this range.

[0052] In some embodiments, a first insulating member 4 is further included. The first insulating member 4 is arranged between the rivet block 2 and the cover body 1. The first insulating member 4 is provided with a receiving groove. The rivet block 2 is arranged in the receiving groove of the first insulating member 4. The top surface of the rivet block 2 is higher than the top surface of the first insulating member 4, and the height difference is C, in mm, satisfying: 4%≤C / (A+C)≤20%.

[0053] In this embodiment, a first insulating member 4 is provided between the rivet block 2 and the cover body 1, providing an insulated connection between the rivet block 2 and the cover body 1. In this embodiment, the first insulating member 4 is the external insulating member described above. Excessive expansion of the straight edge of the pole 3 can cause localized expansion and deformation of the rivet block 2 and the first insulating member 4, resulting in dimensional deviations and the risk of cracking the first insulating member 4, compromising the insulation between the rivet block 2 and the cover body 1.

[0054] Specifically, refer to Figure 4 ,exist Figure 4 In this example, the top surface of the rivet block 2 is the upper surface of the rivet block 2, i.e., the surface of the rivet block 2 that is away from the cover body 1; the top surface of the first insulating member 4 is the upper surface of the first insulating member 4, i.e., the surface of the first insulating member 4 that is farthest from the cover body 1. By further defining the relationship between the height difference C between the top surface of the rivet block 2 and the top surface of the first insulating member 4 and the sum of the depths A of the first hole segment 2011 and the second hole segment 2012, the two satisfy the following relationship: 4% ≤ C / (A + C) ≤ 20%. Otherwise, if the ratio is too small, below 4%, the weld between the pole 3 and the rivet block 2 will protrude, affecting the busbar welding. Meanwhile, if the ratio is too large, above 20%, it will affect the thickness design of the rivet block 2 and is not recommended.

[0055] In some embodiments, the following is also satisfied: 0.15 mm ≤ C ≤ 0.5 mm.

[0056] The height difference C between the top surface of the riveting block 2 and the top surface of the first insulating member 4 is controlled within the range of 0.15 mm to 0.5 mm, which can adapt to various specifications of battery cover assemblies within the range of 1.8 mm ≤ A ≤ 3.6 mm.

[0057] In some embodiments, after the pole body 301 is riveted, it also includes a third column segment 3013 that cooperates with the assembly hole 101 of the cover body 1. The diameter of the third column segment 3013 is larger than the diameter of the first column segment 3011, and the diameter of the second column segment 3012 is larger than the diameter of the first column segment 3011; along the length direction of the cover body 1, the single-sided contact surface width of the second column segment 3012 and the riveted block 2 is D, in mm, and the single-sided contact surface width of the third column segment 3013 and the riveted block 2 is E, in mm, satisfying: 1≤E / D≤10.

[0058] Specifically, the structure of the pole 3 refers to Figure 8 .

[0059] Specifically, refer to Figure 4During the riveting process, the contact surface between the rivet block 2 and the second column segment 3012 supports the terminal 3 during expansion and deformation, while the contact surface between the third column segment 3013 and the rivet block 2 supports the rivet block 2. This embodiment further specifies that the ratio of the width E of the single-sided contact surface between the third column segment 3013 and the rivet block 2 to the width D of the single-sided contact surface between the second column segment 3012 and the rivet block 2 is controlled within a range of 1 to 10. Otherwise, if the ratio is too small, the terminal 3 will not provide sufficient support for the rivet block 2 during the riveting process, making assembly difficult; if the ratio is too large, the diameter of the terminal 3 will be designed to be larger, significantly increasing the weight and cost of the battery cell, which is not conducive to reducing the weight and cost of the battery cell.

[0060] In some embodiments, the following conditions are also satisfied: 0.3 mm ≤ D ≤ 1.5 mm; 0.4 mm ≤ E ≤ 5 mm.

[0061] The width D of the contact surface between the second column section 3012 and the riveting block 2 is controlled within the range of 0.3mm to 1.5mm, and the width E of the contact surface between the third column section 3013 and the riveting block 2 is controlled within the range of 0.4mm to 5mm, which can adapt to 5.5mm 3 ≤V1≤30mm 3 and 5mm 3 ≤V2≤30mm 3 This range includes various specifications of battery cell cover assemblies.

[0062] In order to verify the technical effects of the present invention, three groups of test cases are provided below, including embodiments and comparative examples, and thrust tests, torque tests and dimensional inspections are performed on each case. The above tests and inspections are all performed using methods known to those skilled in the art.

[0063] Thrust test: After the pole 3 is riveted to the rivet block 2, a thrust of 1000N is applied to the pole 3 along the Z direction 10 times. Then a helium test is performed using a special helium test tool and a helium mass spectrometer. The leak rate is less than 1×10-7Pa·m 3 / s is qualified.

[0064] Torque test: After the pole 3 is riveted to the rivet block 2, a torque of 6 N·m is applied 10 times around the Z axis. Then a helium test is performed using a special helium test tool and a helium mass spectrometer. The leak rate is less than 1×10-7 Pa·m. 3 / s is qualified.

[0065] The test results are shown in Tables 1 to 3.

[0066] In addition, it should be noted that, in the experimental cases in each table, except for the variables in the table, the rest of the designs are the same.

[0067] Table 1

[0068]

[0069] Table 1 shows that in Experimental Cases 2 to 13, the V1 / V2 ratio was within the range of 90% to 150%, indicating a good riveting connection between the terminal 3 and the rivet block 2, with neither under-expansion nor over-expansion. Therefore, the welding between the rivet block 2 and the terminal 3 was normal, and the helium inspection after the thrust test passed. The sealing of the cell cover assembly was good, the upper plastic dimensions were qualified, and no cracking occurred. In Experimental Case 1, V1 / V2 was less than 90%, indicating insufficient expansion of the terminal 3, resulting in a large gap between the terminal 3 and the rivet block 2. The rivet block 2 and the terminal 3 could not be welded together, and the helium inspection after the thrust test failed, indicating poor sealing performance. In Experimental Case 14, V1 / V2 was greater than 150%, and excessive expansion occurred in pole 3. At this point, the welding between rivet block 2 and pole 3 was normal, and the helium inspection after the thrust test was passed. The sealing of the battery cover assembly was sufficient, but the rivet position had severe expansion, the dimensions were out of tolerance, and there was a risk of cracking in the plastic, which affected the insulation performance of the battery cell. Therefore, use is not recommended.

[0070] Table 2

[0071]

[0072] Table 2 shows that in Experimental Cases 16 to 28, the B / A ratio ranged from 40% to 60%. After the pole 3 was riveted to the rivet block 2, the thrust test and helium inspection passed, as did the torque test and helium inspection. The cell cover assembly exhibited good thrust resistance and sealing performance. In Experimental Case 15, the B / A value was below 40%. After the pole 3 was riveted to the rivet block 2, the thrust test and helium inspection failed. The sealing performance of the cell cover assembly was poor. Furthermore, there was a high risk of the pole 3 falling off. The overall thrust resistance of the cell cover assembly was poor, and the structural strength was weak. In Experimental Case 29, the B / A value was above 60%. After the pole 3 was riveted to the rivet block 2, the torque test and helium inspection failed. The sealing performance of the cell was poor, and there was a high risk of the rivet block 2 falling off. The overall thrust resistance of the cell cover assembly was poor, and the structural strength was weak.

[0073] Table 3

[0074]

[0075] Table 3 shows that in Experimental Cases 31 to 43, the E / D values ​​range from 1 to 10. The pole 3 and rivet block 2 are riveted normally, passing the helium inspection after the thrust test and the torque test. The cell cover assembly has good thrust resistance and good sealing performance. In Experimental Case 30, the E / D value is lower than 1. During the riveting process, the pole 3 cannot support the riveting pressure of the rivet block 2, making assembly difficult. In Experimental Case 44, the E / D value is higher than 10. The pole 3 and rivet block 2 are riveted normally, passing the helium inspection after the thrust test and the torque test. The cell cover assembly has sufficient thrust resistance and good sealing performance. However, the pole 3 is designed with a large diameter, which significantly increases the weight and cost, and is not recommended.

[0076] In some embodiments, the pole mounting hole 201 further includes a welding sink 2013 disposed on the top of the second hole section 2012 .

[0077] Specifically, in this embodiment, the pole mounting hole 201 of the riveting block 2 is further provided with a welding sink 2013 , and the welding sink 2013 is used to accommodate the weld mark of the riveting block 2 and the pole 3 .

[0078] In some embodiments, the pole 3 further includes a pole bottom plate 303 , which is connected to the third pole section 3013 of the pole 3 . The pole bottom plate 303 and the riveting block 2 are respectively provided on both side surfaces of the cover body 1 .

[0079] In some embodiments, the battery cell cover assembly further includes a second insulating member 5, the rivet block 2 and the first surface of the cover body 1 are insulated and connected by the first insulating member 4, and the pole bottom plate 303 and the second surface of the cover body 1 are insulated and connected by the second insulating member 5.

[0080] Furthermore, 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 body 1 and the rivet block 2, and between the cover body 1 and the terminal 3, thereby preventing short circuits or leakage in the battery cell and improving the safety and reliability of the battery cell.

[0081] The battery cover assembly also includes an explosion-proof valve 7 and an explosion-proof valve patch 8. The cover body 1 is provided with a mounting hole for the explosion-proof valve 7, and the explosion-proof valve 7 is installed in the mounting hole. The explosion-proof valve patch 8 is attached to the upper surface of the mounting hole of the explosion-proof valve 7 to protect the explosion-proof valve 7. The explosion-proof valve 7 is used to quickly explode and release pressure in the event of thermal runaway of the battery cell, thereby ensuring the safety performance of the battery.

[0082] In some embodiments, the cell cover assembly further includes a sealing ring 6. The sealing ring 6 is sleeved on the third column segment 3013 of the pole 3, with at least a portion of the sealing ring 6 disposed between the third column segment 3013 and the assembly hole 101 of the cover body 1, and at least a portion of the sealing ring 6 disposed between the pole bottom plate 303 and the cover body 1. In this way, the sealing ring 6 can form a double seal between the pole 3 and the cover body 1 along the axial and radial directions of the pole 3, thereby improving the sealing, reliability, and safety of the battery cell.

[0083] 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.

[0084] The cell cover assembly is applied to the battery cell to seal the opening of the cell housing, sealing and protecting the internal components of the battery, preventing chemical leakage and the impact of the external environment on the battery. The pole 3 of the cell cover assembly provides a path for current to flow in and out, ensuring current conduction during the battery cell's charging and discharging process. The cell cover assembly not only serves as an electrical connection for the battery cell but also enhances the overall structural stability of the battery cell. It is an important component of the battery cell, ensuring the durability and safety of the battery cell during use.

[0085] 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.

[0086] 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.

[0087] Because the battery pack includes battery cells and has all the technical effects of battery cells, they will not be described here.

[0088] 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 body, wherein the cover plate body is provided with an assembly hole; A riveting block, wherein the riveting block is provided with a pole mounting hole, wherein the pole mounting hole is a stepped hole, comprising a first hole segment and a second hole segment sequentially arranged in a direction away from the cover plate body; The pole, before riveting, includes a pole body, which passes through the assembly hole and the pole mounting hole in sequence. The annular gap between the pole body and the second hole segment constitutes a riveted filling area. The volume of the riveted filling area is V2, in mm. 3 The pole body and the rivet block are riveted together. After riveting, the pole body comprises a first column segment that cooperates with the first hole segment and a second column segment that expands toward the rivet filling area. A concave rivet hole is formed on the top of the second column segment. The volume of the rivet hole is V1, in mm. 3 ; satisfy: 90%≤V1 / V2≤150%.

2. The battery cover assembly according to claim 1, characterized in that: Also meets: 5.5mm 3 ≤V1≤30mm 3 ; 5mm 3 ≤V2≤30mm 3 。 3. The battery cover assembly according to claim 1 or 2, characterized in that: Along the axial direction of the pole mounting hole, the sum of the depths of the first hole segment and the second hole segment is A, in mm, and the depth of the second hole segment is B, in mm, satisfying: 40%≤B / A≤60%.

4. The battery cover assembly according to claim 3, characterized in that: Also meets: 0.9mm≤B≤1.8mm; 1.8mm≤A≤3.6mm.

5. The battery cover assembly according to claim 3, characterized in that: The cover plate further includes a first insulating member, the first insulating member being disposed between the rivet block and the cover plate body, the first insulating member being provided with a receiving groove, the rivet block being disposed in the receiving groove of the first insulating member, the top surface of the rivet block being higher than the top surface of the first insulating member, and the height difference being C (in mm), satisfying: 4%≤C / (A+C)≤20%.

6. The battery cover assembly according to claim 5, characterized in that: Also meets: 0.15mm≤C≤0.5mm.

7. The battery cover assembly according to claim 1 or 2, characterized in that: After being riveted, the pole body further comprises a third column segment that cooperates with the assembly hole of the cover body, wherein the diameter of the third column segment is larger than the diameter of the first column segment, and the diameter of the second column segment is larger than the diameter of the first column segment; Along the length direction of the cover plate body, the width of the single-sided contact surface between the second column segment and the riveting block is D, in mm, and the width of the single-sided contact surface between the third column segment and the riveting block is E, in mm, satisfying: 1≤E / D≤10.

8. The battery cover assembly according to claim 7, characterized in that: Also meets: 0.3mm≤D≤1.5mm; 0.4mm≤E≤5mm.

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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