Battery cell cover plate assembly, battery cell, and battery pack

Abstract

This invention relates to the field of battery cell technology, and discloses a battery cell cover assembly, a battery cell, and a battery pack. The battery cell cover assembly includes: a cover plate with clearance holes; a riveting block disposed on one side of the cover plate, the riveting block having riveting holes, and an annular protrusion on the side of the riveting block facing the cover plate along the thickness direction of the cover plate; and a terminal post including a riveting section and a limiting section, the connection between the riveting section and the limiting section forming a first annular stepped surface. The riveting section passes through the clearance holes to be inserted into the riveting holes, and a portion of the limiting section is inserted into the clearance holes. The first annular stepped surface abuts against the side of the riveting block facing the cover plate; and an annular protrusion is sleeved on the outer side of a portion of the limiting section. By sleeved with an annular protrusion on the outer side of the limiting section, this invention provides lateral support to the limiting section, thus preventing excessive deformation of the limiting section towards its periphery during riveting, which could lead to collapse of the first annular stepped surface.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a cell cover assembly, a cell, and a battery pack. Background Technology

[0002] In current cell cover assembly designs, after the riveting block in the cell cover assembly is riveted to the electrode post, the stepped surface on the electrode post becomes the supporting surface of the bottom of the riveting block along the thickness direction of the cell cover assembly. However, since the electrode post is usually made of copper, aluminum, or copper-aluminum composite materials, although these materials have good conductivity, their structural strength is relatively poor. Therefore, when the riveting part of the electrode post undergoes plastic deformation under external force, the electrode post itself is relatively soft and cannot withstand high pressure. As a result, the stepped surface of the electrode post is prone to deformation or collapse, which in turn leads to the collapse of the riveting block connected to the electrode post. Summary of the Invention

[0003] In view of this, the present invention provides a cell cover plate assembly, a cell, and a battery pack to solve the problem in the prior art where the stepped surface on the electrode post collapses due to stress during the riveting process, causing the riveting block to also collapse.

[0004] In a first aspect, the present invention provides a battery cell cover assembly, comprising:

[0005] The cover plate is equipped with clearance holes;

[0006] A rivet block is provided on one side of the cover plate. The rivet block has a rivet hole and an annular protrusion on the side of the rivet block facing the cover plate along the thickness direction of the cover plate.

[0007] The pole includes a riveting section and a limiting section. The connection between the riveting section and the limiting section forms a first annular stepped surface. The riveting section passes through the clearance opening and is inserted into the riveting hole. A portion of the limiting section is inserted into the clearance hole. The first annular stepped surface abuts against the side of the riveting block facing the cover plate. The annular protrusion is sleeved on the outer side of a portion of the limiting section.

[0008] Beneficial effects: Compared to related solutions where the rivet block faces the cover plate and directly abuts against the stepped surface on the pole post, this invention provides lateral support to the limiting section by sleeved with an annular protrusion on the outside of the limiting section. This not only prevents the rivet area of ​​the rivet block from sinking and ensures the flatness of the upper surface of the rivet block, but also avoids the deformation or cracking of the surrounding structure of the pole post, such as the upper plastic, due to excessive expansion of the limiting section.

[0009] In one optional embodiment, the limiting segment is riveted to the annular protrusion; the height of the annular protrusion is a along the thickness direction of the cover plate, and the value of a is in the range of 0.3mm≤a≤1mm; the width of the annular protrusion is b along the thickness direction perpendicular to the cover plate, and the value of b is in the range of 0.3mm≤b≤2mm.

[0010] Beneficial effects: This invention combines the positioning segment with the annular protrusion through riveting, which not only reduces the gap between them, making the overall structure of the battery cell cover assembly more compact, but also provides lateral support for the positioning segment, preventing it from shifting or wobbling due to uneven force during riveting, thus enhancing the positioning accuracy of the positioning segment. Furthermore, by setting a and b according to the aforementioned range, this invention ensures sufficient contact area between the annular protrusion and the positioning segment, fully utilizing the lateral support effect while preventing the annular protrusion from excessively occupying space.

[0011] In one optional embodiment, the riveting hole includes a first through hole and a second through hole that are connected to each other, the diameter of the first through hole is larger than the diameter of the second through hole, and a second annular stepped surface is formed at the connection between the first through hole and the second through hole; the riveting section includes a main riveting section and a secondary riveting section, the main riveting section is located in the first through hole and is riveted to the first through hole, and the secondary riveting section is located in the second through hole and is riveted to the second through hole.

[0012] Beneficial effects: This invention enlarges the diameter of the first through hole and rivets the main riveting section to the first through hole, which not only increases the contact area between them but also enhances the connection strength between the electrode and the riveting block, reducing the possibility of separation during subsequent use of the battery cell. Secondly, by rivet the secondary riveting section to the second through hole and the annular protrusion, this invention further enhances the connection strength between other parts of the electrode and the riveting block, thereby increasing the electrode's load-bearing capacity in the thickness direction of the battery cell cover assembly and preventing separation of the electrode from the riveting block when subjected to forces along the thickness direction of the battery cell cover assembly. Furthermore, because the electrode deforms downwards and laterally under riveting pressure, a portion of the riveting section abuts against the second annular step surface during riveting, thus limiting the electrode's position in the thickness direction of the battery cell cover assembly.

[0013] In one optional embodiment, along the thickness direction of the cover plate, the thickness of the main riveting section is c, and the value of c ranges from 0.5mm to 2mm; the thickness of the secondary riveting section is d, and the value of d ranges from 0.8mm to 2mm.

[0014] Beneficial effects: If the value of c is less than 0.5mm, breakage and deformation are likely to occur during riveting, making it impossible to form a firm connection. If the value of c is greater than 2mm, the material flowability will be reduced due to excessive thickness, making it difficult for the pole to achieve the ideal material expansion effect during riveting, affecting assembly accuracy and connection stability. If the value of d is less than 0.8mm, the riveting block cannot withstand the riveting pressure, posing a risk of insufficient structural strength. If the value of d is greater than 2mm, it will not only excessively occupy the space in the thickness direction of the cell cover assembly, but also, due to the limitations of material mechanical properties, the strength improvement effect of the pole is limited, thus increasing the cost and weight of the cell cover assembly. Therefore, this invention controls the value of d between 0.8mm and 2mm and the value of c between 0.5mm and 2mm, which can optimize space utilization efficiency while ensuring reliable riveting of the pole and the riveting block, keeping the overall structure of the cell cover assembly compact.

[0015] In one optional embodiment, a riveting groove is formed on the surface of the main riveting section away from the limiting section. Along the thickness direction of the cover plate, the distance between the bottom surface of the riveting groove and the first annular step surface is e. The value range of e satisfies d / 2≤e≤c / 2+d, and e and a satisfy: 1mm≤e+a≤4mm.

[0016] Beneficial effects: If e is less than d / 2, the riveting groove is too shallow, and the main riveting section cannot expand sufficiently to its surroundings during riveting, resulting in a weak riveting connection between the electrode post and the riveting block. If e is greater than c / 2+d, the remaining effective thickness of the main riveting section will be insufficient, affecting the structural strength and potentially disrupting the internal spatial layout of the cell cover assembly. Limiting the relationship between e and a to 1mm≤e+a≤4mm not only effectively prevents the second step from expanding to its surroundings, ensuring the flatness of the riveting block, but also strengthens the connection between the electrode post and the riveting block, improving the overall stability and reliability of the cell cover assembly.

[0017] In one alternative embodiment, along the thickness direction perpendicular to the cover plate, the outer wall of the main riveting section away from the limiting section is welded to the inner wall of the riveting hole to form a weld mark.

[0018] Beneficial effects: The present invention welds the outer wall of the main riveting section to the inner wall of the riveting hole, which on the one hand can improve the connection strength between the pole and the riveting block, and on the other hand can reduce the contact resistance between the two, ensuring the reliability of current conduction.

[0019] In one optional embodiment, along the thickness direction perpendicular to the cover plate, the abutment width between the first annular step surface and the side of the rivet block facing the cover plate is f, where f ranges from 0.2mm ≤ f ≤ 2mm.

[0020] Beneficial effects: The present invention sets the value of f in the range of 0.2mm to 2mm, which on the one hand ensures that there is sufficient contact area between the first annular step surface and the side of the rivet block facing the cover plate, and ensures that the first annular step surface can provide sufficient support for the rivet block. On the other hand, it can reduce the processing difficulty of the first annular step surface.

[0021] In one alternative embodiment, the annular protrusion is integrally formed with the rivet block.

[0022] Beneficial effects: The annular protrusion and the rivet block are integrally formed, which can reduce the production difficulty and improve the connection strength between the two.

[0023] Secondly, the present invention also provides a battery cell, comprising:

[0024] The pole assembly has a pole tab at one end;

[0025] In the aforementioned cell cover assembly, the end of the limiting section away from the riveting section is provided with a pole post base, the pole post base is located outside the clearance hole, and the pole post base is welded to the electrode tab.

[0026] Beneficial effects: The battery cell of the present invention includes the battery cell cover assembly as described above, and has all the beneficial technical effects of the battery cell cover assembly, which will not be repeated here.

[0027] Thirdly, the present invention also provides a battery pack comprising: a plurality of the above-described battery cells.

[0028] Beneficial effects: The battery cell package of the present invention includes the battery cell as described above and has all the beneficial technical effects of the battery cell, which will not be repeated here. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a front view of a battery cell cover assembly according to an embodiment of the present invention;

[0031] Figure 2 for Figure 1 An exploded view of the battery cell cover assembly shown in the figure;

[0032] Figure 3 for Figure 1 A cross-sectional view of the cell cover assembly shown;

[0033] Figure 4 for Figure 3 A magnified view of part M in the diagram;

[0034] Figure 5 for Figure 1 The cross-sectional view of the rivet block shown.

[0035] Explanation of reference numerals in the attached figures:

[0036] 1. Riveting block; 101. Riveting hole; 1011. First through hole; 1012. Second through hole; 1013. Second annular step surface; 102. Annular protrusion; 2. Pole post; 201. Riveting section; 2011. Main riveting section; 2012. Secondary riveting section; 2013. First annular step surface; 202. Limiting section; 203. Riveting groove; 204. Pole post base; 3. Weld mark; 4. Cover plate; 401. Clearance hole. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] In view of the problem that the stepped surface on the pole collapses due to stress during the riveting process in the prior art, causing the riveting block to also collapse, the present invention provides a cell cover plate assembly, a cell, and a battery pack.

[0039] The following is combined with Figures 1 to 5 The following describes embodiments of the present invention.

[0040] According to embodiments of the present invention, in one aspect, such as Figures 1 to 4 As shown, a battery cell cover assembly is provided, including: a cover plate 4, a riveting block 1, and an electrode post 2.

[0041] Specifically, the cover plate 4 is provided with a clearance hole 401; the riveting block 1 is provided on one side of the cover plate 4, the riveting block 1 is provided with a riveting hole 101, and along the thickness direction of the cover plate 4, the side of the riveting block 1 facing the cover plate 4 is provided with an annular protrusion 102; the pole post 2 includes a riveting section 201 and a limiting section 202, the connection between the riveting section 201 and the limiting section 202 forms a first annular stepped surface 2013, the riveting section 201 passes through the clearance hole 401 so that it is inserted into the riveting hole 101, a part of the limiting section 202 is inserted into the clearance hole 401, and the first annular stepped surface 2013 abuts against the side of the riveting block 1 facing the cover plate 4; a part of the limiting section 202 is fitted with an annular protrusion 102 on the outer side.

[0042] Compared to related solutions where the side of the riveting block 1 facing the cover plate 4 directly abuts against the stepped surface on the pole post 2, this embodiment of the invention provides lateral support for the limiting section 202 by sleeved with an annular protrusion 102 on the outside of the limiting section 202. This prevents the limiting section 202 from deforming excessively to its periphery during the riveting process, thus avoiding the collapse of the first annular stepped surface 2013. In this way, not only can the riveting area of ​​the riveting block 1 be prevented from sinking, ensuring the flatness of the upper surface of the riveting block 1, but it can also prevent the structure around the pole post 2, such as the upper plastic, from deforming or cracking due to the excessive expansion of the limiting section 202.

[0043] It is understandable that since both the rivet block 1 and the annular protrusion 102 are sleeved on the outside of the pole post 2, it means that the annular protrusion 102 has an assembly hole inside that allows the pole post 2 to pass through and communicate with the rivet hole 101.

[0044] According to one embodiment of the present invention, such as Figure 4 As shown, the limiting segment 202 is riveted to the annular protrusion 102; along the thickness direction of the cover plate 4, the height of the annular protrusion 102 is a, and the value of a is 0.3mm≤a≤1mm; along the thickness direction perpendicular to the cover plate 4, the width of the annular protrusion 102 is b, and the value of b is 0.3mm≤b≤2mm.

[0045] In this embodiment of the invention, the limiting segment 202 and the annular protrusion 102 are riveted together. This not only reduces the gap between them, making the overall structure of the battery cell cover assembly more compact, but also provides lateral support for the limiting segment 202, preventing it from shifting or shaking due to uneven force during riveting, thus enhancing the positioning accuracy of the limiting segment 202. Furthermore, by setting a and b according to the aforementioned range, this embodiment ensures that the annular protrusion 102 and the limiting segment 202 have sufficient contact area, fully utilizing the lateral support effect while preventing the annular protrusion 102 from excessively occupying space.

[0046] Specifically, if both a and b are less than 0.3 mm, it means that the size of the annular protrusion 102 is relatively small. Therefore, the molding difficulty of the annular protrusion 102 will increase, and the strength of the molded annular protrusion 102 will also decrease, thus failing to effectively provide lateral support. If the value of a is greater than 1 mm and the value of b is greater than 2 mm, it means that the size of the annular protrusion 102 is relatively large. In this case, although the annular protrusion 102 has good structural strength, it will excessively occupy the space in the thickness, length, and width directions of the cell cover assembly, making it prone to interference with other structures and affecting the energy density of the cell.

[0047] It should be noted that the value of 'a' can be, but is not limited to, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1mm. The value of 'b' can be, but is not limited to, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, and 2mm.

[0048] According to one embodiment of the present invention, such as Figure 4 and Figure 5 As shown, the riveting hole 101 includes a first through hole 1011 and a second through hole 1012 that are connected. The diameter of the first through hole 1011 is larger than the diameter of the second through hole 1012. The connection between the first through hole 1011 and the second through hole 1012 forms a second annular stepped surface 1013. The riveting section 201 includes a main riveting section 2011 and a secondary riveting section 2012. The main riveting section 2011 is located inside the first through hole 1011 and is riveted to the first through hole 1011. The secondary riveting section 2012 is located inside the second through hole 1012 and is riveted to the second through hole 1012. In this embodiment of the invention, the diameter of the first through hole 1011 is made larger, and the main riveting section 2011 is riveted to the first through hole 1011. This not only increases the contact area between the two, but also improves the connection strength between the electrode post 2 and the riveting block 1, reducing the possibility of separation between the two during subsequent use of the battery cell. Secondly, in this embodiment of the invention, the riveting of the secondary riveting section 2012 with the second through hole 1012 can also improve the connection strength between other positions of the electrode post 2 and the riveting block 1, thereby improving the load-bearing capacity of the electrode post 2 in the thickness direction of the cell cover assembly and preventing the electrode post 2 from separating from the riveting block 1 when subjected to a force along the thickness direction of the cell cover assembly. Furthermore, since the electrode post 2 deforms downwards and circumferentially after being subjected to riveting pressure, a portion of the structure of the riveting section 201 will abut against the second annular step surface 1013 during the riveting process, thus limiting the electrode post 2 in the thickness direction of the cell cover assembly.

[0049] According to one embodiment of the present invention, such as Figure 4As shown, along the thickness direction of the cover plate 4, the thickness of the main riveting section 2011 is c, and the value of c ranges from 0.5mm to 2mm; the thickness of the secondary riveting section 2012 is d, and the value of d ranges from 0.8mm to 2mm. If the value of c is less than 0.5mm, problems such as breakage and deformation are likely to occur during riveting, making it impossible to form a firm connection. If the value of c is greater than 2mm, the material flowability will be reduced due to excessive thickness, making it difficult for the pole post 2 to achieve the ideal material expansion effect during riveting, affecting assembly accuracy and connection stability. If the value of d is less than 0.8mm, the riveting block 1 will be unable to withstand the riveting pressure, posing a potential risk of insufficient structural strength. If the value of d is greater than 2mm, it will not only excessively occupy the space in the thickness direction of the cell cover plate assembly, but also, due to the limitations of material mechanical properties, the strength improvement effect of the pole post 2 will be limited, thus increasing the cost and weight of the cell cover plate assembly. As can be seen, by controlling the value range of d to between 0.8 mm and 2 mm and the value range of c to between 0.5 mm and 2 mm in the embodiments of the present invention, the space utilization efficiency can be optimized while ensuring reliable riveting of the pole post 2 and the riveting block 1, so that the overall structure of the battery cell cover assembly remains compact.

[0050] It should be noted that the value of 'c' can be, but is not limited to, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, and 2mm. The value of 'd' can be, but is not limited to, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, and 2mm.

[0051] According to one embodiment of the present invention, such as Figure 3 and Figure 4 As shown, a riveting groove 203 is formed on the surface of the main riveting section 2011 away from the limiting section 202. Along the thickness direction of the cover plate 4, the distance between the bottom surface of the riveting groove 203 and the first annular step surface 2013 is e. The value of e satisfies d / 2≤e≤c / 2+d, and e and a satisfy: 1mm≤e+a≤4mm. If e is less than d / 2, the riveting groove 203 is too shallow, and the main riveting section 2011 cannot fully expand to its surroundings during riveting, resulting in the pole post 2 and the riveting block 1 being not firmly riveted. If e is greater than c / 2+d, the remaining effective thickness of the main riveting section 2011 will be insufficient, affecting the structural strength and possibly damaging the internal spatial layout of the cell cover plate assembly. Limiting the relationship between e and a to 1mm≤e+a≤4mm not only effectively prevents the second step from expanding in all directions and ensures the flatness of the rivet block 1, but also strengthens the connection strength between the pole post 2 and the rivet block 1, thereby improving the overall stability and reliability of the cell cover assembly.

[0052] According to one embodiment of the present invention, such as Figure 3 and Figure 4 As shown, along the thickness direction perpendicular to the cover plate 4, the outer wall of the main riveting section 2011 away from the limiting section 202 is welded to the inner wall of the riveting hole 101 to form a weld mark 3. In this embodiment of the invention, welding the outer wall of the main riveting section 2011 to the inner wall of the riveting hole 101 can, on the one hand, improve the connection strength between the pole post 2 and the riveting block 1, and on the other hand, reduce the contact resistance between the two, ensuring the reliability of current conduction.

[0053] According to one embodiment of the present invention, such as Figure 3 and Figure 4 As shown, along the thickness direction perpendicular to the cover plate 4, the contact width between the first annular step surface 2013 and the side of the rivet block 1 facing the cover plate 4 is f, and the value of f ranges from 0.2mm ≤ f ≤ 2mm. In this embodiment of the invention, the value of f is set between 0.2mm and 2mm. This ensures sufficient contact area between the first annular step surface 2013 and the side of the rivet block 1 facing the cover plate 4, guaranteeing that the first annular step surface 2013 can provide sufficient support for the rivet block 1. Furthermore, it reduces the processing difficulty of the first annular step surface 2013.

[0054] It should be noted that the value of f can be, but is not limited to, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, and 2mm.

[0055] According to one embodiment of the present invention, the annular protrusion 102 and the riveting block 1 are integrally formed. In this way, the manufacturing difficulty can be reduced and the connection strength between the two can be improved.

[0056] According to an embodiment of the present invention, another aspect provides a battery cell, comprising: an electrode assembly and the aforementioned battery cell cover plate assembly.

[0057] Specifically, one end of the electrode assembly is provided with an electrode tab; the end of the electrode post 2 limiting section 202 in the above-mentioned cell cover plate assembly away from the riveting section 201 is provided with an electrode post base 204, the electrode post base 204 is located outside the clearance hole 401, and the electrode post base 204 is welded to the electrode tab.

[0058] The battery cell of the present invention includes the battery cell cover assembly as described above, and has all the beneficial technical effects of the battery cell cover assembly, which will not be repeated here.

[0059] In one embodiment, the electrode assembly includes a plurality of alternately arranged positive and negative electrode plates and a separator disposed between the positive and negative electrode plates. Specifically, the positive electrode plate includes a positive current collector and a positive active material disposed on at least one surface of the positive current collector. As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the opposite surfaces of the positive current collector. As an example, the positive current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, silver-surfaced aluminum or stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc., can be used. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. The composite current collector may include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming metallic materials (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.). As an example, the positive electrode active material may include at least one of the following: lithium phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present invention is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for battery cells may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphates include, but are not limited to, lithium iron phosphate (such as LiFePO4 (also abbreviated as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites, at least one of these.

[0060] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector. As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the opposite surfaces of the negative electrode current collector. As an example, the negative electrode current collector may be a metal foil, foamed metal, or a composite current collector. For example, as a metal foil, silver-treated aluminum or stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc., may be used. The composite current collector may include a polymeric material substrate and a metal layer. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymeric material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.). As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc.

[0061] In some embodiments, the separator is a separator membrane. The present invention does not impose particular limitations on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected. As an example, the main material of the separator membrane can be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics.

[0062] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0063] It should be further noted that the electrode tabs in this embodiment include positive electrode tabs and negative electrode tabs. The positive electrode tab is formed by the portion of the positive electrode plate that does not contain active material, and the negative electrode tab is formed by the portion of the negative electrode plate that does not contain active material. The negative electrode tab and the positive electrode tab can be located together at one end of the electrode assembly or separately at both ends of the electrode assembly.

[0064] According to an embodiment of the present invention, another aspect provides a battery pack comprising a plurality of the aforementioned battery cells.

[0065] The battery pack of the present invention includes the battery cell as described above, and has all the beneficial technical effects of the battery cell, which will not be repeated here.

[0066] The effects of the embodiments of the present invention will be explained below with reference to some examples and comparative examples.

[0067] Table 1

[0068]

[0069] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A cell cover assembly, characterized in that, include: The cover plate is equipped with clearance holes; A rivet block is provided on one side of the cover plate. The rivet block has a rivet hole and an annular protrusion on the side of the rivet block facing the cover plate along the thickness direction of the cover plate. The pole includes a riveting section and a limiting section. The connection between the riveting section and the limiting section forms a first annular stepped surface. The riveting section passes through the clearance hole so that it is inserted into the riveting hole. A portion of the limiting section is inserted into the clearance hole. The first annular stepped surface abuts against the side of the riveting block facing the cover plate. The annular protrusion is sleeved on the outer side of a portion of the limiting section.

2. The cell cover assembly according to claim 1, characterized in that, The limiting segment is riveted to the annular protrusion; along the thickness direction of the cover plate, the height of the annular protrusion is a, and the value of a is 0.3mm≤a≤1mm; along the thickness direction perpendicular to the cover plate, the width of the annular protrusion is b, and the value of b is 0.3mm≤b≤2mm.

3. The cell cover assembly according to claim 2, characterized in that, The riveting hole includes a first through hole and a second through hole that are connected. The diameter of the first through hole is larger than the diameter of the second through hole. The connection between the first through hole and the second through hole forms a second annular stepped surface. The riveting section includes a main riveting section and a secondary riveting section. The main riveting section is located in the first through hole and is riveted to the first through hole. The secondary riveting section is located in the second through hole and is riveted to the second through hole.

4. The cell cover assembly according to claim 3, characterized in that, Along the thickness direction of the cover plate, the thickness of the main riveting section is c, and the value of c is in the range of 0.5mm≤c≤2mm; the thickness of the secondary riveting section is d, and the value of d is in the range of 0.8mm≤d≤2mm.

5. The cell cover assembly according to claim 4, characterized in that, A riveting groove is formed on the surface of the main riveting section away from the limiting section. Along the thickness direction of the cover plate, the distance between the bottom surface of the riveting groove and the first annular step surface is e. The value range of e satisfies d / 2≤e≤c / 2+d, and e and a satisfy: 1mm≤e+a≤4mm.

6. The cell cover assembly according to claim 3, characterized in that, Along the thickness direction perpendicular to the cover plate, the outer wall of the main riveting section away from the limiting section is welded to the inner wall of the riveting hole to form a weld mark.

7. The cell cover assembly according to any one of claims 1 to 6, characterized in that, Along the thickness direction perpendicular to the cover plate, the abutment width between the first annular step surface and the side of the rivet block facing the cover plate is f, and the value of f is in the range of 0.2mm≤f≤2mm.

8. The cell cover assembly according to any one of claims 1 to 6, characterized in that, The annular protrusion is integrally formed with the rivet block.

9. A battery cell, characterized in that, include: The pole assembly has a pole tab at one end; According to any one of claims 1 to 8, the end of the limiting section away from the riveting section is provided with a pole post base, the pole post base is located outside the clearance hole, and the pole post base is welded to the pole tab.

10. A battery pack, characterized in that, include: The battery cell as described in several claims 9.

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