Battery cell cover plate assembly, battery cell and battery pack

Abstract

The invention relates to the technical field of battery cells, 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 provided with an avoiding hole; the riveting block is arranged on one side of the cover plate, a riveting hole is formed in the riveting block, and an annular protrusion is arranged on the side, facing the cover plate, of the riveting block in the thickness direction of the cover plate; the pole comprises a riveting section and a limiting section, a first annular step surface is formed at the joint of the riveting section and the limiting section, the riveting section penetrates through the avoiding opening to be arranged in the riveting hole in a penetrating manner, part of the limiting section is arranged in the avoiding hole in a penetrating manner, and the first annular step surface abuts against the side, facing the cover plate, of the riveting block; the outer side of the limiting section is partially sleeved with an annular protrusion. The outer side of the limiting section is sleeved with the annular protrusion, the annular protrusion can provide lateral support for the limiting section, and therefore the situation that the limiting section excessively deforms towards the circumferential side in the riveting process, and consequently the first annular step face collapses can be avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a battery cell cover plate assembly, a battery cell and a battery pack. BACKGROUND

[0002] In the current design of the battery cell cover plate assembly, after the riveting block in the battery cell cover plate assembly is riveted with the pole column in the battery cell cover plate assembly, the stepped surface on the pole column will become the supporting surface of the bottom surface of the riveting block along the thickness direction of the battery cell cover plate assembly. However, since the pole column is usually made of copper, aluminum or copper-aluminum composite material, these materials have good electrical conductivity but relatively poor structural strength. Therefore, after the riveting part of the pole column is plastically deformed under external force, the stepped surface of the pole column is prone to deformation or collapse due to the softness of the pole column itself, which in turn causes the collapse of the riveting block connected to the pole column. SUMMARY

[0003] Therefore, the present application provides a battery cell cover plate assembly, a battery cell and a battery pack to solve the problem that the stepped surface on the pole column collapses during riveting due to stress.

[0004] In a first aspect, the present application provides a battery cell cover plate assembly, comprising: a cover plate provided with a clearance hole; a riveting block provided on one side of the cover plate, the riveting block being provided with a riveting hole, and the riveting block being provided with an annular protrusion on the side facing the cover plate along the thickness direction of the cover plate; a pole column comprising a riveting section and a limiting section, the connecting part of the riveting section and the limiting section forming a first annular stepped surface, the riveting section penetrating through the clearance hole and being provided in the riveting hole, part of the limiting section penetrating through the clearance hole, the first annular stepped surface abutting against the side of the riveting block facing the cover plate, and part of the limiting section being provided with the annular protrusion.

[0005] Advantages: Compared with the related scheme in which the side of the riveting block facing the cover plate directly abuts against the stepped surface on the pole column, the present application provides lateral support for the limiting section by providing the annular protrusion on the outside of the limiting section, which not only prevents the riveting area of the riveting block from sinking and ensures the flatness of the upper surface of the riveting block, but also prevents the structure on the side of the pole column, such as the upper plastic, from deforming or cracking due to excessive expansion of the limiting section.

[0006] In an optional embodiment, the limiting section 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 range 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 range of b is 0.3mm≤b≤2mm.

[0007] Beneficial Effects: The present invention rivets the limiting segment and the annular protrusion together, not only reducing the gap between them and making the overall structure of the cell cover assembly more compact, but also providing lateral support for the limiting segment, preventing the limiting segment from shifting or shaking due to uneven force during the riveting process, thereby enhancing the accuracy of the limiting segment's positioning. Furthermore, by setting a and b within the aforementioned ranges, the present invention ensures sufficient contact area between the annular protrusion and the limiting segment, fully utilizing the lateral support effect while preventing the annular protrusion from excessively occupying space.

[0008] In an optional embodiment, the rivet hole includes a first through hole and a second through hole that are connected to each other, the aperture of the first through hole is larger than the aperture of the second through hole, and a second annular step surface is formed at the connection between the first through hole and the second through hole; the rivet section includes a main rivet section and a secondary rivet section, the main rivet section is located in the first through hole and riveted with the first through hole, and the secondary rivet section is located in the second through hole and riveted with the second through hole.

[0009] Beneficial effects: The present invention enlarges the aperture of the first through hole and rivets the main riveted section with the first through hole, which not only increases the contact area between the two, but also increases the connection strength between the pole and the riveted block, reducing the possibility of the two being separated during the subsequent use of the battery cell. Secondly, the present invention rivets the secondary riveted section with the second through hole and the annular protrusion, which can also improve the connection strength between other positions of the pole and the riveted block, thereby improving the bearing capacity of the pole in the thickness direction of the battery cell cover assembly and preventing the pole from being separated from the riveted block when subjected to a force along the thickness direction of the battery cell cover assembly. In addition, since the pole will deform downward and circumferentially after being subjected to riveting pressure, part of the structure of the riveted section will abut against the second annular step surface during the riveting process, completing the limitation of the pole in the thickness direction of the battery cell cover assembly.

[0010] In an optional embodiment, along the thickness direction of the cover plate, the thickness of the main riveted section is c, and the value range of c is 0.5mm≤c≤2mm; the thickness of the secondary riveted section is d, and the value range of d is 0.8mm≤d≤2mm.

[0011] Beneficial effects: If the value of c is less than 0.5mm, problems such as breakage and deformation are likely to occur during riveting, and a firm connection cannot be formed; if the value of c is greater than 2mm, the material fluidity will deteriorate due to the excessive thickness, and it will be difficult for the pole to achieve the ideal material expansion effect during the riveting process, affecting the assembly accuracy and connection stability. If the value of d is less than 0.8mm, the rivet block will be unable to withstand the riveting pressure, and there is a hidden danger of insufficient structural strength; if the value of d is greater than 2mm, not only will it excessively occupy the space in the thickness direction of the battery cover assembly, but due to the limitations of the material mechanical properties, the strength improvement effect of the pole is limited, thereby increasing the cost and weight of the battery cover assembly. It can be seen that the present invention controls the value range of d to between 0.8mm and 2mm and the value range of c to between 0.5mm and 2mm, while ensuring reliable riveting of the pole and the rivet block, optimizing space utilization efficiency and keeping the overall structure of the battery cover assembly compact.

[0012] In an optional embodiment, a rivet groove is formed on the surface of the main riveted section away from the limiting section. Along the thickness direction of the cover plate, the distance between the bottom surface of the rivet groove and the first annular step surface is e, and the value range of e satisfies d / 2≤e≤c / 2+d, and the relationship between e and a satisfies: 1mm≤e+a≤4mm.

[0013] Beneficial Effects: If e is less than d / 2, the rivet groove is too shallow, and the main riveted section cannot fully expand toward its surroundings during riveting, resulting in a weak riveted connection between the pole and the riveted block. If e is greater than c / 2 + d, the remaining effective thickness of the main riveted section is insufficient, affecting structural strength and potentially damaging the internal spatial layout of the battery cell cover assembly. Limiting the relationship between e and a to 1mm ≤ e + a ≤ 4mm effectively prevents the second step from expanding toward its surroundings, ensuring the flatness of the riveted block. It also strengthens the bond between the pole and the riveted block, improving the overall stability and reliability of the battery cell cover assembly.

[0014] In an optional embodiment, along a direction perpendicular to the thickness of the cover plate, an outer side wall of the main riveting section away from one end of the limiting section is welded to an inner side wall of the riveting hole to form a weld mark.

[0015] Beneficial effects: The present invention welds the outer wall of the main riveted section to the inner wall of the riveted hole, which can improve the connection strength between the pole and the riveted block on the one hand, and reduce the contact resistance between the two on the other hand, thereby ensuring the reliability of current conduction.

[0016] In an optional embodiment, along a direction perpendicular to the thickness of the cover plate, a contact width between the first annular step surface and a side of the rivet block facing the cover plate is f, and a value range of f is 0.2 mm ≤ f ≤ 2 mm.

[0017] Beneficial effects: the present application sets the value range of f between 0.2mm and 2mm, on the one hand, it can ensure that the first annular stepped surface and the side of the riveting block facing the cover plate have sufficient contact area, and ensure that the first annular stepped surface can provide sufficient support force for the riveting block, on the other hand, it can reduce the processing difficulty of the first annular stepped surface.

[0018] In an alternative embodiment, the annular protrusion is integrally formed with the riveting block.

[0019] Beneficial effects: the annular protrusion is integrally formed with the riveting block, which can reduce the production difficulty and improve the connection strength of the two.

[0020] In a second aspect, the present application also provides an electric core, comprising: a pole group, provided with a tab at one end; The electric core cover plate assembly described above, the limiting section is provided with a pole base at one end away from the riveting section, the pole base is located outside the avoiding hole, and the pole base is welded with the tab.

[0021] Beneficial effects: the electric core of the present application comprises the electric core cover plate assembly as described above, which has all the beneficial technical effects of the electric core cover plate assembly, which will not be repeated here.

[0022] In a third aspect, the present application also provides a battery pack, comprising: a plurality of the electric core described above.

[0023] Beneficial effects: the electric core pack of the present application comprises the electric core as described above, which has all the beneficial technical effects of the electric core, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0025] Figure 1 It is a front view of an electric core cover plate assembly of an embodiment of the present application; Figure 2 It is Figure 1 It is an exploded view of the electric core cover plate assembly shown in the figure; Figure 3 It is Figure 1 It is a sectional view of the electric core cover plate assembly shown in the figure; Figure 4 It is Figure 3 It is a local enlarged schematic view of M in the figure; Figure 5 It is Figure 1 A sectional view of the riveting block shown in the middle.

[0026] Explanation of reference signs: 1, riveting block; 101, riveting hole; 1011, first through hole; 1012, second through hole; 1013, second annular stepped surface; 102, annular protrusion; 2, pole column; 201, riveting section; 2011, main riveting section; 2012, secondary riveting section; 2013, first annular stepped surface; 202, limiting section; 203, riveting groove; 204, pole column base; 3, welding mark; 4, cover plate; 401, avoiding hole. DETAILED DESCRIPTION

[0027] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0028] In view of the problem that the stepped surface on the pole column collapses in the riveting process due to stress, causing the riveting block to collapse, the present application provides an electric core cover plate assembly, an electric core and a battery pack.

[0029] The embodiments of the present application will be described below with reference to the drawings. Figures 1 to 5

[0030] According to the embodiments of the present application, on one hand, as shown in Figures 1 to 4 , an electric core cover plate assembly is provided, comprising: a cover plate 4, a riveting block 1 and a pole column 2.

[0031] Specifically, the cover plate 4 is provided with an avoiding hole 401; the riveting block 1 is arranged 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 riveting block 1 is provided with an annular protrusion 102 on the side facing the cover plate 4; the pole column 2 comprises a riveting section 201 and a limiting section 202, the connecting part of the riveting section 201 and the limiting section 202 forms a first annular stepped surface 2013, the riveting section 201 passes through the avoiding hole 401 so as to be arranged in the riveting hole 101, part of the limiting section 202 is arranged in the avoiding hole 401, the first annular stepped surface 2013 abuts against the side of the riveting block 1 facing the cover plate 4; part of the outer side of the limiting section 202 is sleeved with the annular protrusion 102.

[0032] ​Compared with the related solutions in which the side of the rivet block 1 facing the cover plate 4 is directly abutted against the step surface on the pole 2, the embodiment of the present invention provides an annular protrusion 102 on the outer side of the limiting section 202, so that the annular protrusion 102 can provide lateral support for the limiting section 202, thereby preventing the limiting section 202 from excessively deforming toward its circumferential side during the riveting process, causing the first annular step surface 2013 to collapse. In this way, not only can the riveted area of ​​the rivet block 1 be prevented from sinking and the flatness of the upper surface of the rivet block 1 be ensured; at the same time, it can also prevent the structure on the circumferential side of the pole 2, such as the upper plastic, from being deformed or cracked due to excessive expansion of the limiting section 202.

[0033] It is understandable that since the rivet block 1 and the annular protrusion 102 are both sleeved on the outside of the pole 2 , it means that an assembly hole is provided inside the annular protrusion 102 for the pole 2 to pass through and communicate with the rivet hole 101 .

[0034] According to one embodiment of the present invention, Figure 4 As shown, the limiting section 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 range 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 range of b is 0.3mm≤b≤2mm.

[0035] In this embodiment of the present invention, the riveted connection between the limiting segment 202 and the annular protrusion 102 not only reduces the gap between them, making the overall structure of the 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 the riveting process, thereby enhancing the positioning accuracy of the limiting segment 202. Furthermore, by setting a and b within the aforementioned ranges, this embodiment of the present invention ensures sufficient contact area between the annular protrusion 102 and the limiting segment 202, fully maximizing the lateral support effect while also preventing the annular protrusion 102 from excessively occupying space.

[0036] Specifically, if the values ​​of a and b are both less than 0.3mm, the annular protrusion 102 is relatively small, making it more difficult to form the annular protrusion 102. Furthermore, the strength of the formed annular protrusion 102 is also reduced, making it unable to effectively provide lateral support. If the value of a is greater than 1mm and the value of b is greater than 2mm, the annular protrusion 102 is relatively large. While the annular protrusion 102 has good structural strength, it will occupy excessive space in the thickness, length, and width of the cell cover assembly, making it prone to interference with other structures and affecting the energy density of the cell.

[0037] It should be noted that the value of a can be, but is not limited to, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, and 1 mm. The value of b can be, but is not limited to, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, and 2 mm.

[0038] According to one embodiment of the present invention, Figure 4 and Figure 5 As shown, the rivet hole 101 includes a first through hole 1011 and a second through hole 1012 that are connected. The aperture of the first through hole 1011 is larger than that of the second through hole 1012. A second annular step surface 1013 is formed at the connection between the first through hole 1011 and the second through hole 1012. The rivet section 201 includes a main rivet section 2011 and a secondary rivet section 2012. The main rivet section 2011 is located in the first through hole 1011 and is riveted to the first through hole 1011. The secondary rivet section 2012 is located in the second through hole 1012 and is riveted to the second through hole 1012. In the embodiment of the present invention, the aperture of the first through hole 1011 is enlarged, and the main rivet 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 2 and the rivet block 1, reducing the possibility of separation between the two during subsequent use of the battery cell. Secondly, the embodiment of the present invention rivets the secondary rivet section 2012 with the second through hole 1012, which can also improve the connection strength between the other positions of the pole 2 and the riveted block 1, thereby improving the load-bearing capacity of the pole 2 in the thickness direction of the battery cell cover assembly and preventing the pole 2 from separating from the riveted block 1 when subjected to forces along the thickness direction of the battery cell cover assembly. In addition, because the pole 2 deforms downward and lateral to the riveting pressure, part of the riveted section 201 will abut against the second annular step surface 1013 during the riveting process, thus limiting the position of the pole 2 in the thickness direction of the battery cell cover assembly.

[0039] According to one embodiment of the present invention, Figure 4As shown, along the thickness direction of the cover plate 4, the thickness of the primary riveted section 2011 is c, with a value range of c being 0.5mm≤c≤2mm; the thickness of the secondary riveted section 2012 is d, with a value range of d being 0.8mm≤d≤2mm. If the value of c is less than 0.5mm, problems such as breakage and deformation are likely to occur during riveting, and a secure connection cannot be formed. If the value of c is greater than 2mm, the excessive thickness will lead to poor material fluidity, making it difficult to achieve the ideal expansion effect of the pole 2 during the riveting process, affecting assembly accuracy and connection stability. If the value of d is less than 0.8mm, the riveted block 1 will be unable to withstand the riveting pressure, posing a risk of insufficient structural strength. If the value of d is greater than 2mm, not only will it occupy excessive space in the thickness direction of the battery cell cover plate assembly, but due to the limitations of the material's mechanical properties, the strength improvement effect of the pole 2 will be limited, thereby increasing the cost and weight of the battery cell cover plate assembly. It can be seen that the embodiment of the present invention controls the value range of d to between 0.8 mm and 2 mm, and controls the value range of c to between 0.5 mm and 2 mm, which can optimize space utilization efficiency while ensuring reliable riveting between the pole 2 and the rivet block 1, so that the overall structure of the battery cover assembly remains compact.

[0040] It should be noted that the value of c can be, but is not limited to, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, and 2 mm. The value of d can be, but is not limited to, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, and 2 mm.

[0041] According to one embodiment of the present invention, Figure 3 and Figure 4 As shown, a rivet groove 203 is formed on the surface of the main riveted section 2011 at the end away from the limiting section 202. Along the thickness direction of the cover plate 4, the distance between the bottom surface of the rivet groove 203 and the first annular step surface 2013 is e, and the value range of e satisfies d / 2≤e≤c / 2+d, and the relationship between e and a satisfies: 1mm≤e+a≤4mm. If e is less than d / 2, the rivet groove 203 is too shallow, and the main riveted section 2011 cannot fully expand around it during riveting, resulting in a loose riveting connection between the pole 2 and the riveted block 1. If e is greater than c / 2+d, the remaining effective thickness of the main riveted section 2011 is insufficient, affecting the structural strength and potentially damaging the internal spatial layout of the battery cell cover plate assembly. Limiting the relationship between e and a to 1mm≤e+a≤4mm can not only effectively prevent the second step from swelling around and ensure the flatness of the riveted block 1, but also strengthen the bonding strength between the pole 2 and the riveted block 1, thereby improving the overall stability and reliability of the battery cover assembly.

[0042] According to one embodiment of the present invention, Figure 3 and Figure 4 As shown, the outer wall of the main riveted section 2011 at the end away from the limiting section 202 is welded to the inner wall of the riveted hole 101 in a direction perpendicular to the thickness of the cover plate 4, forming a weld mark 3. In this embodiment of the present invention, welding the outer wall of the main riveted section 2011 to the inner wall of the riveted hole 101 can not only improve the connection strength between the terminal 2 and the riveted block 1, but also reduce the contact resistance between the two, thereby ensuring the reliability of current conduction.

[0043] According to one embodiment of the present invention, Figure 3 and Figure 4 As shown, along a direction perpendicular to the thickness of 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 range of f is 0.2mm≤f≤2mm. In this embodiment of the present invention, the value range 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, ensuring that the first annular step surface 2013 can provide sufficient support for the rivet block 1. It also reduces the difficulty of machining the first annular step surface 2013.

[0044] 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.

[0045] According to one embodiment of the present invention, the annular protrusion 102 is integrally formed with the riveting block 1. This can reduce production difficulty and improve the connection strength between the two.

[0046] According to an embodiment of the present invention, on the other hand, a battery cell is provided, comprising: an electrode group and the above-mentioned battery cell cover assembly.

[0047] Specifically, a pole ear is provided at one end of the pole group; a pole base 204 is provided at one end of the pole 2 limiting section 202 away from the riveted section 201 in the above-mentioned battery cover assembly. The pole base 204 is located outside the avoidance hole 401 and is welded to the pole ear.

[0048] The battery cell of the present invention includes the battery cell cover plate assembly as described above, and has all the beneficial technical effects of the battery cell cover plate assembly, which will not be described in detail here.

[0049] In one embodiment, the pole group in the present embodiment includes a plurality of positive electrode sheets and negative electrode sheets alternately arranged and separators arranged between the positive electrode sheets and the negative electrode sheets. Specifically, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material arranged on at least one surface of the positive electrode current collector. As an example, the positive electrode current collector has two surfaces opposite in the thickness direction thereof, and the positive electrode active material is arranged on either one or both of the two opposite surfaces of the positive electrode current collector. As an example, the positive electrode current collector can employ a metal foil, a foamed metal, or a composite current collector. For example, as the metal foil, silver surface-treated aluminum or stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, or the like can be employed. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, or the like. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, or the like) on a polymer material base material (such as a polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like). As an example, the positive electrode active material can include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and modified compounds of each of them. However, the present application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials of battery cells can also be used. These positive electrode active materials can be used alone only one kind, or two or more kinds can be used in combination. Among them, examples of the lithium-containing phosphates can include, but are not limited to, at least one of lithium iron phosphate (such as LiFeP04 (which can also be referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnP04), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon.

[0050] 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. For example, the negative electrode current collector has two opposing surfaces along its thickness, with the negative electrode active material disposed on either or both of the opposing surfaces. For example, the negative electrode current collector may be a metal foil, metal foam, or a composite current collector. For example, the metal foil may include silver-treated aluminum or stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium. The composite current collector may include a polymer base layer and a metal layer. The metal foam may include nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. The composite current collector may be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy) on a polymer substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.). For example, the negative electrode active material may be any negative electrode active material commonly used 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, lithium titanate, and the like.

[0051] In some embodiments, the separator is a separator membrane. The present invention does not particularly limit the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be used. For example, the separator membrane can be primarily made of at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic.

[0052] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0053] It should be noted that the tabs in this embodiment include positive and negative tabs. The positive tab is composed of the portion of the positive electrode sheet that does not contain active material, and the negative tab is composed of the portion of the negative electrode sheet that does not contain active material. The negative and positive tabs can be located together at one end of the electrode assembly or separately at both ends of the electrode assembly.

[0054] According to an embodiment of the present invention, on the other hand, a battery pack is provided, comprising: a plurality of the above-mentioned battery cells.

[0055] 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 described in detail here.

[0056] The effects of the embodiments of the present invention are described below in combination with some embodiments and comparative examples.

[0057] Table 1

[0058] 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: The cover plate is provided with an avoidance hole; A rivet block is provided on one side of the cover plate, the rivet block is provided with a rivet hole, and along the thickness direction of the cover plate, the rivet block is provided with an annular protrusion on the side facing the cover plate; The pole includes a riveted section and a limiting section, wherein a first annular step surface is formed at the connection between the riveted section and the limiting section, the riveted section passes through the avoidance hole so as to be inserted into the riveted hole, and a portion of the limiting section is inserted into the avoidance hole, and the first annular step surface abuts against the side of the riveted block facing the cover plate; the annular protrusion is partially sleeved on the outer side of the limiting section.

2. The battery cover assembly according to claim 1, characterized in that: The limiting section 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 range 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 range of b is 0.3mm≤b≤2mm.

3. The battery cover assembly according to claim 2, characterized in that: The rivet hole includes a first through hole and a second through hole that are connected to each other, the aperture of the first through hole is larger than the aperture of the second through hole, and a second annular step surface is formed at the connection between the first through hole and the second through hole; the rivet section includes a main rivet section and a secondary rivet section, the main rivet section is located in the first through hole and is riveted to the first through hole, and the secondary rivet section is located in the second through hole and is riveted to the second through hole.

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

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

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

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

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

9. A battery cell, characterized in that: include: The pole group has a pole ear at one end; The battery cell cover plate assembly according to any one of claims 1 to 8, wherein a pole base is provided at one end of the limiting section away from the riveted section, the pole base is located outside the avoidance hole, and the pole base is welded to the pole lug.

10. A battery pack, characterized in that: include: A plurality of battery cells according to claim 9.

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