Cover plate, battery cell and battery pack

Abstract

The invention relates to the technical field of batteries, and discloses a cover plate, a battery cell and a battery pack, and the cover plate comprises a cover plate body, a riveting block, a pole and a first insulating part. The length and the width of the weak area of the cover plate and the riveting block with the structure meet 0.5 < = L / M < = 10, M > = 1.5 mm, and the length-width ratio of the weak area is less than or equal to 10, so that the lower limit value of the width of the weak area and the upper limit value of the length-width ratio of the weak area can be ensured, the weak area is prevented from forming a long and thin strip shape with longer length and narrower width, the strength of the weak area can be ensured, and the service life of the cover plate and the riveting block is prolonged. The riveting block is stressed when the pole is riveted, the strength of the riveting block in the weak area is high, the riveting block cannot be extruded and deformed by force towards the outer side of the width direction of the riveting hole, the riveting block in the weak area can be effectively prevented from expanding outwards, the size of the riveting block in the width direction is stable, and the width size error of the riveting block can be controlled within a required range; and it can be guaranteed that the width size of the riveting block and the overall size of the riveting block meet the design requirement.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a cover plate, a battery cell and a battery pack. Background Art

[0002] The cover plate that adopts the pole riveting fixation method includes a riveting block, a first insulating member, a cover plate body, a second insulating member, a pole and a sealing ring. The pole includes a base plate and a column portion. The cover plate body is provided with a mounting hole, and the riveting block is provided with a riveting hole. The column portion passes through the mounting hole and the riveting hole and is riveted to the riveting block. The connection between the pole and the riveted block is then reinforced by laser welding.

[0003] Existing columns are generally cylindrical. For cells with narrow, long covers and high current requirements, the narrow width of the cover body prevents increasing the current capacity of the cell by increasing the diameter of the cylindrical column. Instead, the column can only be enlarged along the length of the cover body, resulting in a narrow, long column. Accordingly, the rivet hole also becomes narrow and long. The inventors have discovered that compared to circular rivet holes, narrow, long rivet holes have weaker rivet blocks along the width of the rivet hole. This can easily cause the rivet blocks on both sides of the rivet hole to expand outward during pole riveting, resulting in an out-of-tolerance rivet block width and a failure to meet design requirements. Summary of the Invention

[0004] In view of this, the present invention provides a cover plate, a battery cell and a battery pack to solve the problem in the prior art that the narrow and long cover plate has a pole and a rivet block with a narrow and long rivet hole, which easily leads to out-of-tolerance dimensional errors after the pole is riveted.

[0005] In a first aspect, the present invention provides a cover plate, comprising:

[0006] The cover body is provided with a mounting hole;

[0007] A rivet block is provided on one side of the outer surface of the cover plate body; the length of the rivet block is greater than the width of the rivet block, and the rivet block is provided with a rivet hole extending along the length direction of the rivet block; the length of the rivet hole is greater than the width of the rivet hole; the rivet hole is provided with at least one middle smooth region in the length direction, and the hole wall of the long side of the rivet hole located in the middle smooth region is parallel to the long side of the rivet block; within the middle smooth region, along the width direction of the cover plate, the width of the rivet block on one side of the rivet hole is M, the length of the middle smooth region is L, and the width of the cover plate body is K, 0.5≤L / M≤10; 1.5mm≤M≤(K-6.5mm) / 2, and the units of M, L, and K are all mm;

[0008] The pole comprises a base plate and a column portion provided on the base plate, the column portion passing through the mounting hole and the rivet hole and being riveted to the rivet block; the base plate is located on one side of the inner surface of the cover plate body; the column portion and the rivet block extend in the same direction, the length of the column portion is greater than the width of the column portion, and the cross-sectional shape of the column portion is adapted to the shape of the rivet hole;

[0009] The first insulating member is arranged on the outer surface of the cover body. The outer surface of the first insulating member is provided with a mounting groove, and the rivet block is arranged in the mounting groove.

[0010] Beneficial effect: In the cover plate of this structure, the hole wall of the long side of the rivet hole in the middle smooth area is parallel to the long side of the rivet block, the thickness of the rivet block in the area between one end of the width direction of the rivet block and the hole wall of the long side of the corresponding side rivet hole is thinner, and the strength of the rivet block in this area is relatively weak. This area is the weak area of ​​the rivet block, and the width M between one end of the width direction of the rivet block and the corresponding side hole wall of the rivet hole is the width of the weak area. The length L of the middle smooth area is the length of the weak area. 0.5≤L / M≤10, M≥1.5mm, and the aspect ratio of the weak area is less than or equal to 10. In this way, the lower limit of the width of the weak area and the upper limit of the aspect ratio of the weak area can be guaranteed, and the weak area can be prevented from forming a long and narrow slender strip, thereby ensuring the strength of the weak area. When riveting the pole, the riveted block is subjected to force, and the riveted block in the weak area has high strength and will not be squeezed and deformed by the force toward the outside of the width direction of the riveted hole. It can effectively prevent the riveted block in the weak area from expanding outward, and the width direction dimension of the riveted block is stable. The width dimension error of the riveted block can be controlled within the required range, which can ensure that the width dimension of the riveted block and the overall dimension of the riveted block meet the design requirements.

[0011] In an optional embodiment, along the length direction of the rivet hole, the rivet hole also includes arc-shaped areas provided at both ends of the middle smooth area, the hole wall of the rivet hole at the arc-shaped area is an arc surface, and the hole wall of the rivet hole at the middle smooth area smoothly transitions to the hole wall of the rivet hole at the arc-shaped area.

[0012] In an optional embodiment, the arc-shaped area is a semicircular arc, the middle smooth area is a rectangle, the diameter of the semicircular arc is equal to the width of the middle smooth area; and the cross section of the column portion is a racetrack shape.

[0013] In an optional embodiment, the width of the rivet hole is W, the total length of the rivet hole is L1, 2.5 mm ≤ L ≤ 20 mm, 2.5 mm ≤ W ≤ 0.9 L1.

[0014] In an optional embodiment, the cover body further includes a first insulating member disposed on an outer surface thereof, wherein a mounting groove is disposed on the outer surface of the first insulating member, and the rivet block is disposed within the mounting groove; a distance between one end of the cover body in the width direction and an outer side wall of the first insulating member on the corresponding side is K1, and a width of the first insulating member located on one side of the mounting groove in the width direction is K2, where K1 is ≥ 1.5 mm;

[0015] and / or, 0.5mm≤K2≤1mm.

[0016] In an optional embodiment, the outer surface of the rivet block protrudes from the outer surface of the first insulating member, and the height between the outer surface of the rivet block and the outer surface of the first insulating member is h, 0.1 mm≤h≤0.5 mm.

[0017] In an optional embodiment, a first step is provided on the inner wall of the rivet hole, and the width of the step surface of the first step at all circumferential locations is the same, and the width of the step surface of the first step is b, 0.2mm≤b≤0.5mm.

[0018] In an optional embodiment, a second step is provided on the inner wall of the rivet hole between the first step and the outer surface of the rivet block along the thickness direction of the cover plate, the width of the step surface of the second step at all circumferential locations is the same, and the step surface width of the second step is a, 0.5mm≤a≤1.5mm.

[0019] In a second aspect, the present invention further provides a battery cell comprising a housing and a cover plate as described above, wherein the housing has an opening and the cover plate is disposed over the opening. The battery cell including the cover plate has the same technical effects as the cover plate and will not be further described here.

[0020] In a third aspect, the present invention further provides a battery pack comprising the aforementioned battery cell. The battery pack includes a cover plate, which has the same technical effects as the cover plate and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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.

[0022] Figure 1 This is a schematic diagram of the three-dimensional structure of a cover plate according to an embodiment of the present invention;

[0023] Figure 2 for Figure 1a top view of the cover plate shown;

[0024] Figure 3 for Figure 2 AA section view;

[0025] Figure 4 for Figure 3 A partial enlarged schematic diagram;

[0026] Figure 5 for Figure 2 BB section view (excluding dimension marks);

[0027] Figure 6 for Figure 2 BB section view (including dimension markings);

[0028] Figure 7 for Figure 1 Top view of the middle riveting block;

[0029] Figure 8 for Figure 1 Schematic diagram of the three-dimensional structure of the middle riveting block;

[0030] Figure 9 for Figure 1 Schematic diagram of the three-dimensional structure of the middle pole (before the pole is riveted);

[0031] Figure 10 for Figure 1 Exploded view of the cover shown.

[0032] Description of reference numerals:

[0033] 1. Cover plate body; 2. Riveted block; 21. Riveted hole; 211. Middle smooth area; 212. Arc area; 213. First step; 214. Second step; 3. Pole; 31. Bottom plate; 32. Column; 4. First insulating member; 41. Mounting groove; 5. Second insulating member; 6. Sealing member. DETAILED DESCRIPTION

[0034] 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.

[0035] In the related art, for battery cells with narrow and long covers and large overcurrent requirements, due to the narrow width of the cover body, it is impossible to increase the overcurrent capacity of the battery cell by increasing the diameter of the cylindrical column portion. Instead, the column portion can only be increased in the length direction of the cover body, thereby forming a narrow and long column portion. Correspondingly, the rivet hole is also narrow and long. The inventors have found that compared with circular rivet holes, the width of the rivet blocks on both sides of the rivet hole width direction is thinner, and the strength of the rivet blocks in this area is weaker. The riveting of the pole on the rivet block can easily cause the rivet blocks on both sides of the rivet hole width to expand outward, resulting in the rivet block width size being out of tolerance and the rivet block size failing to meet the requirements; the circumferential side wall of the rivet block is wrapped with the first insulating member. When the rivet block expands outward severely, it may even crack the first insulating member, causing the first insulating member to lose its insulation protection function for the rivet block.

[0036] The following combination Figures 1 to 10 , describing embodiments of the present invention.

[0037] When the cover is mounted on the opening of the cell casing, the side of the cover with components facing the outside of the casing is called the outer surface, and the side of the cover with components facing the inside of the casing is called the inner surface.

[0038] According to an embodiment of the present invention, in one aspect, a cover plate is provided, including a cover plate body 1 , a riveting block 2 , a pole 3 and a first insulating member 4 .

[0039] The cover body 1 is provided with a mounting hole; the rivet block 2 is provided on one side of the outer surface of the cover body 1; the length of the rivet block 2 is greater than the width of the rivet block 2, and the rivet block 2 is provided with a rivet hole 21 extending along the length direction of the rivet block 2; the length of the rivet hole 21 is greater than the width of the rivet hole 21; the rivet hole 21 is provided with at least one middle smooth area 211 along the length direction, and the hole wall of the long side of the rivet hole 21 located in the middle smooth area 211 is parallel to the long side of the rivet block 2; within the middle smooth area 211, along the width direction of the cover, the width of the rivet block 2 on one side of the rivet hole 21 is M, the length of the middle smooth area 211 is L, and the width of the cover body 1 is K. 5≤L / M≤10; 1.5mm≤M≤(K-6.5mm) / 2, where the units of M, L, and K are all mm; the pole 3 includes a base plate 31 and a column portion 32 provided on the base plate 31, the column portion 32 passing through the mounting hole and the rivet hole 21 and riveted to the rivet block 2; the base plate 31 is located on one side of the inner surface of the cover body 1; the column portion 32 extends in the same direction as the rivet block 2 and the length of the column portion 32 is greater than the width of the column portion 32, and the cross-sectional shape of the column portion 32 is adapted to the shape of the rivet hole 21; the first insulating member 4 is provided on the outer surface of the cover body 1, and a mounting groove 41 is provided on the outer surface of the first insulating member 4, and the rivet block 2 is provided in the mounting groove 41.

[0040] In the cover plate of this structure, the long side wall of the rivet hole 21 located in the middle smooth area 211 is parallel to the long side of the rivet block 2. Along the width direction of the cover plate, the thickness of the rivet block 2 on one side of the rivet hole 21 is thinner, and the strength of the rivet block 2 in this area is relatively weak. This area is the weak area of ​​the rivet block 2. The width M between one end of the rivet block 2 in the width direction and the corresponding side hole wall of the rivet hole 21 is the width of the weak area. The length L of the middle smooth area 211 is the length of the weak area. 0.5≤L / M≤10, M≥1.5mm, and the aspect ratio of the weak area is less than or equal to 10, which can ensure the thin area. The lower limit of the width of the weak zone and the upper limit of the aspect ratio of the weak zone prevent the weak zone from forming a long and narrow slender strip, thereby ensuring the strength of the weak zone. When riveting the pole 3, the riveted block 2 is subjected to force. The riveted block 2 at the weak zone has high strength and will not be squeezed and deformed by the force toward the outside of the width direction of the riveted hole 21. It can effectively prevent the riveted block 2 in the weak zone from expanding outward. The width direction dimension of the riveted block 2 is stable, and the width dimension error of the riveted block 2 can be controlled within the required range, which can ensure that the width dimension of the riveted block 2 and the overall dimension of the riveted block 2 meet the design requirements.

[0041] Along the width direction of the cover body 1, the area between the outer wall of the first insulating part 4 and the edge of the cover body 1 needs to be wrapped with a blue film and a top cover patch is affixed on the cover body 1. If the width of the area between the outer wall of the first insulating part 4 and the edge of the cover body 1 is too small, the blue film and the top cover patch will warp; at the same time, a certain width of space is required in the width direction of the cover body 1 to accommodate the first insulating part 4 on the side of the mounting groove 41. Therefore, M≤(K-6.5mm) / 2. This setting can ensure the width of the area between the outer wall of the first insulating part 4 and the edge of the cover body 1, ensure the flatness of the blue film and the top cover patch, and prevent the blue film and the top cover patch from warping; at the same time, sufficient space is reserved in the width direction of the cover body 1 to accommodate the first insulating part 4, which can effectively ensure the thickness of the first insulating part 4 located on one side of the mounting groove 41 in the width direction, thereby ensuring the insulation protection effect of the first insulating part 4 on the rivet block 2; the thickness of the first insulating part 4 is not too small, which is also convenient for injection molding the first insulating part 4.

[0042] The cross-sectional shape of the column portion 32 is adapted to the shape of the rivet hole 21, which means that the cross-sectional shape of the column portion 32 is the same as the shape of the rivet hole 21. For example, when the rivet hole 21 is elliptical, the cross-sectional shape of the column portion 32 is elliptical; when the rivet hole 21 is rectangular, the cross-sectional shape of the column portion 32 is correspondingly rectangular. The column portion 32 passes through the rivet hole 21, and the circumferential sidewalls of the column portion 32 are attached to the sidewalls of the rivet hole 21.

[0043] In some optional embodiments, such as Figure 7 and Figure 8As shown, along the length of the rivet hole 21, the rivet hole 21 further includes curved areas 212 located at both ends of the central smooth area 211. The wall of the rivet hole 21 at the curved areas 212 is a curved surface, and the wall of the rivet hole 21 at the central smooth area 211 smoothly transitions to the wall of the rivet hole 21 at the curved areas 212. The cross-sectional shape of the column portion 32 matches the shape of the rivet hole 21, i.e., a smooth area is provided in the middle of the column portion 32 along its length, and curved areas are provided at both ends of the smooth area. The sidewalls of the smooth area and the curved areas of the column portion 32 smoothly transition to each other. The rivet block 2 of the first part is fixed with the rivet 32 ​​at the bottom, and the rivet 32 ​​at the bottom is fixed with the rivet 32 ​​at the bottom.

[0044] In some embodiments, the arc-shaped area 212 is a semicircular arc, the middle smooth area 211 is a rectangle, and the diameter of the semicircular arc is equal to the width of the middle smooth area 211; the cross-section of the column portion 32 is runway-shaped. The runway shape refers to the middle area of ​​the column portion 32 being rectangular and the two ends of the middle area being semicircular. This arrangement can further improve the uniformity of the material expansion at various circumferential positions of the column portion 32 during riveting, ensure that the circumferential positions of the column portion 32 can effectively fit with the riveted block 2, further improve the reliability of the welding between the column portion 32 and the riveted block 2, ensure the conductive effect of the pole 3 and the riveted block 2, ensure the stability of the internal resistance and battery operation, and ensure the strength of the cover plate.

[0045] The column portion 32 passes through the rivet hole 21, and the length and width of the rivet hole 21 limit the length and width of the column portion 32. When the pole 3 is riveted, the rivet punch acts on the outer surface of the column portion 32. If the length and width of the rivet hole 21 are too small, the length and width of the column portion 32 will also be small accordingly. At this time, the outer surface area of ​​the column portion 32 is small, making it difficult to ensure the force application space of the rivet punch. If a smaller rivet punch is selected, the strength of the rivet punch cannot be guaranteed, and thus it is difficult to ensure the riveting expansion effect of the rivet punch. If the length L of the middle smooth area 211 of the rivet hole 21 is too long, the length of the column portion 32 will be longer accordingly, which will result in poor expansion effect at both ends of the length direction of the column portion 32 during riveting, resulting in uneven expansion of the column portion 32 around the circumference, which will affect the welding of the column portion 32 and the rivet block 2, resulting in reduced strength of the cover plate, and also resulting in poor welding appearance at the welding position of the column portion 32 and the rivet block 2.

[0046] To avoid these problems, in some embodiments, Figure 7 As shown, the width of the rivet hole 21 is W, and the total length of the rivet hole 21 is L1, 2.5mm≤L≤20mm, 2.5mm≤W≤0.9L1. W≥2.5mm, L≥2.5mm, thus ensuring the lower limit of the length and width of the rivet hole 21, thereby ensuring the lower limit of the length and width of the column portion 32, and further ensuring that there is sufficient space on the outer surface of the column portion 32. Then, a rivet punch of appropriate size can be selected to rivet the pole 3, which can ensure the strength of the rivet punch and its riveting and material expansion effect on the column portion 32. L≤20mm, which can prevent the length of the middle smooth area 211 of the rivet hole 21 from being too long, thereby preventing the length of the column part 32 from being too long, and can ensure the expansion effect at both ends of the length direction of the column part 32, so as to ensure that the column part 32 is expanded evenly at all places in the circumference, and can ensure that the column part 32 and the riveted block 2 are effectively fitted, and can ensure the reliability of the welding between the column part 32 and the riveted block 2, and can ensure the strength of the cover plate, and at the same time, can also ensure that the welding position between the column part 32 and the riveted block 2 is flat, and can ensure the beauty of the welding appearance.

[0047] Riveted blocks 2 with different M, L, and L / M values ​​were designed and assembled into a cover plate. The width of the riveted blocks 2 was observed and compared with the theoretical design value of the riveted blocks 2. The shape of the first insulating member 4 was also observed. The test results are shown in Table 1.

[0048] Table 1

[0049]

[0050] As can be seen from Examples 1 to 8, when M, L, and L / M satisfy 0.5≤L / M≤10; 1.5mm≤M≤(K-6.5mm) / 2, the strength of the weak area of ​​the riveted block 2 can be guaranteed. When the riveted block 2 is subjected to force when riveted to the pole 3, the riveted block 2 in the weak area can be effectively prevented from expanding outward. The width direction of the riveted block 2 is stable, and the width dimension error of the riveted block 2 can be controlled within the required range. As can be seen from Comparative Example 1, when L / M>10, due to the large aspect ratio of the weak area of ​​the riveted block 2, the weak area is in the shape of a slender strip, and the strength of the weak area is low. After the pole 3 is riveted, the riveted block 2 in the weak area expands outward, and the width direction dimension of the riveted block 2 does not meet the requirements. At this time, the first insulating member 4 does not crack. It can be seen from Comparative Example 2 that when L>20mm, the length of the middle smooth area 211 of the rivet hole 21 is too long, which causes the length of the column part 32 to be too long, the expansion effect at both ends of the length direction of the column part 32 is not good, the riveting expansion of the column part 32 is uneven, and the welding appearance of the column part 32 and the rivet block 2 is not good; it can be seen from Comparative Example 3 that when M<1.5mm, the width of the weak area is too small, the strength of the weak area is low, and after the pole 3 is riveted, the rivet block 2 in the weak area expands outward, and the width direction dimension of the rivet block 2 does not meet the requirements. It can be seen from Comparative Example 4 that when M is less than 1.5 mm, L is greater than 20 mm, and L / M is greater than 10, the width of the weak zone is too small, the length of the weak zone is long, and the aspect ratio of the weak zone is large, resulting in low strength of the weak zone, which causes the width dimension of the rivet block 2 to not meet the requirements and the first insulating member 4 to crack; since the length of the middle smooth area 211 of the rivet hole 21 is too long, the length of the column portion 32 is too long, the expansion effect at both ends of the length direction of the column portion 32 is not good, the riveting expansion of the column portion 32 is uneven, and the welding appearance of the column portion 32 and the rivet block 2 is poor.

[0051] In other embodiments, the rivet hole 21 may also be a rectangular hole. In this case, the rivet hole 21 only includes a middle smooth area 211 in the length direction.

[0052] like Figure 5 and Figure 6 As shown, the distance between one end of the cover body 1 in the width direction and the outer side wall of the first insulating member 4 on the corresponding side is K1, and the width of the first insulating member 4 on one side of the width direction of the mounting groove 41 is K2, K1 ≥ 1.5 mm. This setting can ensure the distance between one end of the cover body 1 in the width direction and the outer side wall of the first insulating member 4 on the corresponding side, and can ensure that the cover body 1 has a sufficient width on the outside of the first insulating member 4 in the width direction, which is convenient for covering the cover body 1 in this area with a blue film and attaching a top cover patch, and can ensure the flatness of the blue film and the top cover patch.

[0053] In some embodiments, 0.5mm≤K2≤1mm. This setting can ensure the minimum wall thickness of the side wall of the first insulating member 4 on one side of the mounting groove 41, and can ensure the insulation protection effect of the first insulating member 4 on the riveted block 2, while avoiding K2 being too large and occupying too much space; the first insulating member 4 is a plastic member, and the first insulating member 4 is generally manufactured by injection molding. The wall thickness of the side wall of the first insulating member 4 is moderate, and its thickness is not too small, which is convenient for injection molding of the first insulating member 4.

[0054] like Figure 6 As shown, in some embodiments, the outer surface of the rivet block 2 protrudes from the outer surface of the first insulating member 4, and the height between the outer surface of the rivet block 2 and the outer surface of the first insulating member 4 is h, 0.1mm≤h≤0.5mm. This arrangement can ensure that there is a sufficient height difference between the outer surface of the rivet block 2 and the outer surface of the first insulating member 4, and when the bar is subsequently welded to the rivet block 2, the welding heat can be prevented from melting and damaging the first insulating member 4; at the same time, it can also prevent the height difference between the outer surface of the rivet block 2 and the outer surface of the first insulating member 4 from being too large, and can ensure the covering height of the side wall of the first insulating member 4 to the circumferential side wall of the rivet block 2, and can ensure the insulation protection effect of the first insulating member 4 on the rivet block 2, and can effectively prevent the tools from knocking and damaging the rivet block 2 during the assembly of the cover plate and the battery cell, and can avoid damaging the rivet block 2 and generating metal debris, and can ensure the safety performance of the battery cell.

[0055] like Figure 5 、 Figure 7 and Figure 8As shown, a first step 213 is provided on the inner wall of the rivet hole 21. The width of the step surface of the first step 213 is the same at all circumferential locations. The width of the step surface of the first step 213 is b. After the column portion 32 is riveted, its expanded deformation zone is supported on the step surface of the first step 213 of the rivet block 2. If the width of the first step 213 is too small, it will be inconvenient to form the first step 213 during the manufacture of the rivet block 2. At the same time, it will also cause the rivet block 2 to be unable to effectively support the pole 3, which will affect the connection strength between the column portion 32 and the rivet block 2 after riveting. In addition, after the column portion 32 is riveted, its expanded deformation zone needs to fill the step surface of the first step 213, so that the circumferential side wall of the column portion 32 abuts the hole wall of the rivet hole 21, ensuring the fit between the column portion 32 and the rivet block 2. If the step surface of the first step 213 is wide, the distance between the circumferential side wall of the column portion 32 and the wall of the riveting hole 21 before riveting is large, and it is difficult for the column portion 32 to fill the first step 213 after the material is expanded, resulting in a gap between the circumferential side wall of the column portion 32 and the wall of the riveting block 2, which can easily lead to a cold weld between the column portion 32 and the riveting block 2 after welding. In order to avoid these problems, in some embodiments, 0.2mm≤b≤0.5mm, which can ensure that the first step 213 has a sufficient width to facilitate the formation of the first step 213 and at the same time ensure the supporting effect of the first step 213 on the pole 3; in addition, it can also prevent the step surface of the first step 213 from being too wide, ensuring that the circumferential side wall of the column portion 32 can fit on the wall of the riveting hole 21 after the material is expanded, thereby ensuring the reliability of the welding between the pole 3 and the riveting block 2 after welding, and ensuring the stability of the internal resistance of the battery cell and the battery performance.

[0056] A second step 214 is provided on the inner wall of the rivet hole 21 between the first step 213 and the outer surface of the rivet block 2 along the thickness direction of the cover plate. The width of the step surface of the second step 214 is uniform at all locations along the circumference. After the column portion 32 is riveted and expanded, it is welded to the rivet block 2. The weld mark has a certain thickness and width, and the groove formed in the second step 214 is used to accommodate the weld mark. The step surface width of the second step 214 is a, 0.5mm≤a≤1.5mm. This ensures that the step surface of the second step 214 is wide enough to accommodate the weld mark, while also preventing a value of a from being too large and occupying too much space.

[0057] In some embodiments, the height of the second step 214 is c, c ≥ 0.2 mm. This setting can effectively prevent the end face in the thickness direction of the weld from leaking out, thereby ensuring the appearance of the battery cell, while ensuring the flatness of the outer surface of the riveted block 2, and will not affect the subsequent welding of the riveted block 2 and the bar.

[0058] In some embodiments, as Figures 3 to 6As shown, the cover plate further includes a second insulating member 5 and a sealing member 6. The second insulating member 5 is provided on the inner surface of the cover plate body 1, the bottom plate 31 is provided inside the inner surface of the second insulating member 5, the sealing member 6 is provided between the cover plate body 1 and the pole 3, the outer surface of the bottom plate 31 abuts against the sealing member 6, and the column portion 32 passes through the second insulating member 5, the cover plate body 1, the first insulating member 4 and the rivet block 2 and is riveted to the rivet block 2.

[0059] In some embodiments, the bottom plate 31 has a rectangular cross-section, and its cross-sectional area is larger than that of the column portion 32. The outer surface of the bottom plate 31 abuts against the sealing member 6, and the bottom plate 31 and the rivet block 2 clamp the first insulating member 4, the second insulating member 5 of the cover body 1, and the sealing member 6.

[0060] The cover plate can be used for any battery cell with a narrow and long cover plate, such as blade battery cells and square shell battery cells.

[0061] According to an embodiment of the present invention, on the other hand, a battery cell is provided, comprising a housing and the cover plate of the above embodiment, wherein the housing is provided with an opening, and the cover plate is provided on the opening.

[0062] For a battery cell of this structure, the size of its upper cover plate satisfies L / M≤10, M≥1.5mm, that is, the aspect ratio of the weak zone is less than or equal to 10. This ensures the lower limit of the width of the weak zone and the upper limit of the aspect ratio of the weak zone, preventing the weak zone from forming a slender strip with a long length and a narrow width, thereby ensuring the strength of the weak zone. When the riveted block 2 of the riveted pole 3 is subjected to force, the riveted block 2 at the weak zone has high strength and will not be squeezed and deformed by the force toward the outside in the width direction of the riveted hole 21, which can effectively prevent the riveted block 2 in the weak zone from expanding outward. The width direction dimension of the riveted block 2 is stable, and the width dimension error of the riveted block 2 can be controlled within the required range, ensuring that the width dimension and overall dimension of the riveted block 2 meet the design requirements. At the same time, M≤(K-6.5mm) / 2 is satisfied. This setting can ensure the width of the area between the outer wall of the first insulating part 4 and the edge of the cover body 1, and can ensure the flatness of the blue film and the top cover patch; at the same time, sufficient space can be reserved in the width direction of the cover body 1 to accommodate the first insulating part 4, which can effectively ensure the thickness of the first insulating part 4 located on one side of the width direction of the mounting groove 41, and can ensure the insulation protection effect of the first insulating part 4 on the riveted block 2, and also facilitate the injection molding of the first insulating part 4.

[0063] In some optional embodiments, the battery cell includes a blade battery cell, the blade battery cell includes a shell, and the two ends of the shell are open in the length direction. The cover plate includes a positive cover plate and a negative cover plate, a positive electrode column 3 is provided on the positive cover plate, and a negative electrode column 3 is provided on the negative cover plate. The positive cover plate and the negative cover plate are respectively provided on the openings at both ends of the shell.

[0064] In other embodiments, the battery cell includes a prismatic battery cell, and the length of the cover body 1 of the prismatic battery cell is greater than its width.

[0065] According to another aspect of an embodiment of the present invention, a battery pack is provided, comprising the battery cell of the above embodiment.

[0066] For a battery pack of this structure, the dimensions of the upper cover satisfy L / M≤10, M≥1.5mm, that is, the aspect ratio of the weak zone is less than or equal to 10. This ensures the lower limit of the width of the weak zone and the upper limit of the aspect ratio of the weak zone. When riveting the pole 3, it can effectively prevent the rivet block 2 in the weak zone from expanding outward, and the width dimensional error of the rivet block 2 can be controlled within the required range, ensuring that the width dimension and overall dimension of the rivet block 2 meet the design requirements. At the same time, M≤(K-6.5mm) / 2 is satisfied. This setting ensures the width of the area between the outer wall of the first insulating part 4 and the edge of the cover body 1, prevents the blue film and the top cover patch from rising during assembly, and ensures the flatness of the blue film and the top cover patch; at the same time, it ensures the insulation protection effect of the first insulating part 4 on the rivet block 2, and also facilitates the injection molding of the first insulating part 4.

[0067] 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 cover plate, characterized in that: include: The cover body is provided with a mounting hole; A rivet block is provided on one side of the outer surface of the cover plate body; the length of the rivet block is greater than the width of the rivet block, and the rivet block is provided with a rivet hole extending along the length direction of the rivet block; the length of the rivet hole is greater than the width of the rivet hole; the rivet hole is provided with at least one middle smooth region in the length direction, and the hole wall of the long side of the rivet hole located in the middle smooth region is parallel to the long side of the rivet block; within the middle smooth region, along the width direction of the cover plate, the width of the rivet block on one side of the rivet hole is M, the length of the middle smooth region is L, and the width of the cover plate body is K, 0.5≤L / M≤10; 1.5mm≤M≤(K-6.5mm) / 2, and the units of M, L, and K are all mm; The pole comprises a base plate and a column portion provided on the base plate, the column portion passing through the mounting hole and the rivet hole and being riveted to the rivet block; the base plate is located on one side of the inner surface of the cover plate body; the column portion and the rivet block extend in the same direction, the length of the column portion is greater than the width of the column portion, and the cross-sectional shape of the column portion is adapted to the shape of the rivet hole; The first insulating member is arranged on the outer surface of the cover body. The outer surface of the first insulating member is provided with a mounting groove, and the rivet block is arranged in the mounting groove.

2. The cover plate according to claim 1, wherein: Along the length direction of the rivet hole, the rivet hole also includes arc-shaped areas arranged at both ends of the middle smooth area. The hole wall of the rivet hole in the arc-shaped area is an arc surface, and the hole wall of the rivet hole in the middle smooth area transitions smoothly to the hole wall of the rivet hole in the arc-shaped area.

3. The cover plate according to claim 2, wherein: The arc-shaped area is in the shape of a semicircle, the middle smooth area is in the shape of a rectangle, the diameter of the semicircle is equal to the width of the middle smooth area; and the cross section of the column part is in the shape of a racetrack.

4. The cover plate according to any one of claims 1 to 3, characterized in that: The width of the rivet hole is W, the total length of the rivet hole is L1, 2.5mm≤L≤20mm, 2.5mm≤W≤0.9L1.

5. The cover plate according to any one of claims 1 to 3, characterized in that: The distance between one end of the cover body in the width direction and the outer side wall of the first insulating member on the corresponding side is K1, and the width of the first insulating member on one side of the mounting slot in the width direction is K2, where K1 is ≥ 1.5 mm; and / or, 0.5mm≤K2≤1mm.

6. The cover plate according to claim 5, characterized in that: The outer surface of the rivet block protrudes from the outer surface of the first insulating member, and the height between the outer surface of the rivet block and the outer surface of the first insulating member is h, where 0.1 mm≤h≤0.5 mm.

7. The cover plate according to any one of claims 1 to 3, characterized in that: A first step is provided on the inner wall of the rivet hole. The width of the step surface of the first step at each circumference is the same. The width of the step surface of the first step is b, and 0.2mm≤b≤0.5mm.

8. The cover plate according to claim 7, wherein: A second step is provided on the inner wall of the rivet hole between the first step and the outer surface of the rivet block along the thickness direction of the cover plate. The width of the step surface of the second step is the same at all circumferential locations. The step surface width of the second step is a, 0.5mm≤a≤1.5mm.

9. A battery cell, characterized in that: The invention comprises a shell and the cover plate according to any one of claims 1 to 8, wherein the shell is provided with an opening, and the cover plate is arranged on the opening.

10. A battery pack, characterized in that: Including the battery cell according to claim 9.

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