Cover plate and battery cell

Abstract

The invention relates to the technical field of batteries, and discloses a pole, a cover plate and a battery cell. According to the pole, the size of the riveting punch in the length direction of the pole body part is larger, materials corresponding to the arc-shaped areas at the two ends of the pole body part in the length direction can expand outwards farther, and the pole body part obtained after material expansion is tightly attached to the riveting block. A / b is larger than or equal to 0.5 and smaller than or equal to 0.8, so that the wall thickness difference of the arc-shaped area and the middle smooth area of the cylinder part can be prevented from being too large, uniform material expansion of the whole circle in the circumferential direction of the cylinder part can be guaranteed, the reliability of the arc-shaped area and the middle smooth area after welding can be effectively guaranteed, and pseudo soldering is avoided; the thickness difference between the arc-shaped areas and the wall thickness of the cylinder part of the middle smooth area can be prevented from being too small, the length of the pre-riveting groove can be obviously larger than the width of the pre-riveting groove, the size of the riveting punch in the length direction of the pre-riveting groove is correspondingly increased, and materials corresponding to the arc-shaped areas at the two ends of the cylinder part in the length direction can expand outwards farther.

Description

Technical Field

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

[0002] like Figure 1 and Figure 2 As shown, the cover plate using the pole riveting fixation method includes a riveting block 2', a first insulating member, a cover plate body 1', a second insulating member, a pole 3' and a sealing ring. The pole 3' includes a base plate and a column portion 32'. The pole base plate and the riveting block clamp the cover plate components therebetween. The top of the column portion 32' is riveted to the riveting block, and then the connection between the pole and the riveting block is reinforced by laser welding.

[0003] Existing columns are typically cylindrical. For cells with narrow, elongated covers and high current requirements, increasing the current capacity of the cells by increasing the diameter of the cylindrical column is not feasible due to the narrow width of the cover body. Instead, the column must be enlarged along the length of the cover body, resulting in a narrow, elongated column. This non-circular cross-section of the pole can easily lead to uneven material expansion during riveting, preventing the column from effectively fitting into the rivet block after riveting. Laser welding of the column and rivet block can easily result in cold welds and unstable internal resistance. Summary of the Invention

[0004] In view of this, the present invention provides a cover plate and a battery cell to solve the problem in the prior art that the pole column is narrow and long, and the material expands unevenly during riveting, resulting in easy cold welding and unstable internal resistance between the pole column and the riveted block.

[0005] In a first aspect, the present invention provides a pole suitable for use in a cover plate, the cover plate comprising a cover plate body and a rivet block, the cover plate body being provided with a mounting hole, the rivet block being provided with a rivet hole, and the rivet block being provided on the outer side of the cover plate body facing the outer side of the cover plate; the pole comprising:

[0006] The bottom plate and a column portion provided on the bottom plate, the column portion is suitable for passing through the mounting hole and the rivet hole, and the bottom plate is suitable for being provided on the inner side of the other side surface of the cover plate body facing the inner side of the cover plate; the column portion is suitable for extending in the same direction as the rivet block and the length of the column portion is greater than its width, and along the length direction of the cross section of the column portion, the column portion includes a middle smooth area and arc-shaped areas provided at both ends of the middle smooth area; a pre-rivet groove extending in the same direction as the column portion is provided on the side surface of the column portion facing the outer side of the cover plate, and the wall thickness of the column portion at the middle smooth area is greater than the wall thickness of the column portion at the arc-shaped area; the wall thickness of the column portion at the farthest position of the arc-shaped area from the middle smooth area is a, and the wall thickness of the column portion at the middle smooth area is b, 0.5≤a / b≤0.8, and the units of a and b are mm.

[0007] Beneficial effects: In the pole of this structure, a pre-rivet groove extending in the same direction as the column part is provided on the surface of one side of the column part facing the outer side of the cover plate. The wall thickness of the column part in the middle smooth area is greater than the wall thickness of the column part in the arc-shaped area, so that the length of the pre-rivet groove is greater than its width. The shape of the riveting punch corresponds to the pre-rivet groove. The size of the riveting punch in the length direction of the column part is greater than the size in the width direction of the column part, so that the size of the riveting punch in the length direction of the column part is larger. When the pole is riveted, the riveting punch presses the pre-rivet groove downward to apply force, which can make the materials corresponding to the arc-shaped areas at both ends of the length direction of the column part expand further outward, so that the expanded column part is tightly attached to the riveting block. And the wall thickness a of the column part at the farthest position of the arc-shaped area from the middle smooth area before riveting and the wall thickness b of the column part at the middle smooth area satisfy 0.5≤a / b≤0.8, so that the ratio of the wall thickness a of the column part at the farthest position of the arc-shaped area from the middle smooth area before riveting to the wall thickness b of the column part at the middle smooth area can be controlled within a suitable range, which can avoid a large difference in the wall thickness of the column part in the arc-shaped area and the middle smooth area, and can ensure that the whole circle of the column part is evenly expanded, so that after riveting, the expansion The column part fits tightly with the riveting block, which can effectively ensure the reliability of the two after welding and avoid cold welding; it can also prevent the wall thickness difference between the arc area and the middle smooth area of ​​the column part from being too small, so that the length of the pre-rivet groove can be significantly larger than its width, and the size of the rivet punch in the length direction of the pre-rivet groove is correspondingly increased, which can make the material corresponding to the arc area at both ends of the length direction of the column part expand farther outward, so that the column part after expansion is close to the riveting block, which can effectively ensure the reliability of the two after welding and avoid cold welding.

[0008] In an optional embodiment, the arc-shaped area is a semicircular arc, and the side wall of the column portion at a position corresponding to the semicircular arc smoothly transitions to the side wall of the column portion at a position corresponding to the middle smooth area.

[0009] In an optional embodiment, the central smooth area is rectangular, and the diameter of the semicircular arc is equal to the width of the central smooth area; along the circumference of the semicircular arc, from the central smooth area to the minimum wall thickness of the columnar part, the wall thickness of the columnar part gradually decreases.

[0010] In an optional embodiment, 0.5 mm ≤ a ≤ 3 mm, and 0.5 mm ≤ b ≤ 3 mm.

[0011] Beneficial effects: In this way, the wall thickness of the column part on the outer side of the pre-rivet groove can be guaranteed. After the pole column part is riveted, the strength of the pole to be retained on the riveting block can be guaranteed, and the pole can be prevented from falling off when the pole is subjected to a force acting toward the inner side of the cover plate body; at the same time, sufficient welding space can be guaranteed on the side of the column part, and the weld width and the reliability of the welding between the column part and the riveting block can be guaranteed. In addition, it can also prevent the wall thickness of the column part on the side of the pre-rivet groove from being too thick, which makes it difficult to rivet the column part outward.

[0012] In an optional embodiment, the width of the pre-rivet groove is W1, the width of the column portion on the circumferential outer side of the riveting groove is W2, 2mm≤W1<W2-b, and the units of W1 and W2 are mm.

[0013] Beneficial Effects: This ensures the lower limit of the pre-rivet groove width, thereby ensuring the width of the riveting punch, and further ensuring the strength of the riveting punch and the riveting effect. The length of the pre-rivet groove is greater than its width, and the lower limit of the pre-rivet groove width is ensured, thereby ensuring the lower limit of the pre-rivet groove length, thereby ensuring the width and length of the riveting punch, thereby ensuring the strength of the riveting punch and the riveting effect.

[0014] In an optional embodiment, a support step is provided on the circumference of the side wall of the column portion, and the side surface of the rivet block facing the inner side of the cover plate abuts against the support step; the bottom of the pre-rivet groove is flush with the support step or the bottom of the pre-rivet groove is arranged relative to the support step and close to the notch of the pre-rivet groove.

[0015] In a second aspect, the present invention further provides a cover plate, comprising:

[0016] The cover body is provided with a mounting hole;

[0017] a riveting block, provided with a riveting hole and arranged on the outer side of the cover plate body facing the outer side of the cover plate;

[0018] In any of the aforementioned poles, the mounting hole and the rivet hole are formed through the column, and the base plate is disposed on the inner side of the other surface of the cover body facing the inner side of the cover. The column extends in the same direction as the rivet block, and its length is greater than its width. Before the pole is riveted, the wall thickness of the column at the point farthest from the smooth middle section in the curved region is a, and the wall thickness of the column at the smooth middle section is b. The cover includes the pole and has the same technical effects as the pole, and will not be further described here.

[0019] In an optional embodiment, a first step and a second step located on the inner wall of the rivet hole and close to the side surface of the first step facing the outer side of the cover plate, and the deformation zone of the column part after riveting is abutted against the step surface of the first step on the side surface facing the inner side of the cover plate body; the height between the first step and the second step is h1, and h1 ≥ 0.8 mm.

[0020] Beneficial effect: This arrangement can ensure that there is sufficient height between the two steps, which can prevent the welding heat from melting the first step during laser welding, and at the same time ensure the supporting strength of the riveted block, so that the pole can be stably and firmly maintained on the riveted block after connection.

[0021] In an optional embodiment, in a plane parallel to the plane where the cover plate body is located, the width of the step surface of the first step is c, and c≤0.5 mm.

[0022] Beneficial effect: This setting can prevent the step surface of the first step from being too wide, and ensure that the circumferential side wall of the column part can fit on the vertical wall between the two steps of the riveted block after the material is expanded, thereby ensuring the reliability of the welding between the pole and the riveted block after welding, and ensuring the stability of the internal resistance of the battery cell and the battery performance.

[0023] 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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.

[0025] Figure 1 It is a schematic diagram of the three-dimensional structure of the cover plate described in the background technology of the present invention;

[0026] Figure 2 for Figure 1 A partial enlarged view of the middle A part

[0027] Figure 3 This is a schematic diagram of the three-dimensional structure of a cover plate according to an embodiment of the present invention;

[0028] Figure 4 for Figure 1 a top view of the cover plate shown;

[0029] Figure 5 for Figure 4 A partial enlarged view of middle B;

[0030] Figure 6 for Figure 4 AA sectional view;

[0031] Figure 7 for Figure 6 A partial enlarged diagram of C in the middle (after the pole is riveted);

[0032] Figure 8 for Figure 7 Schematic diagram of the pole before riveting (before the pole is riveted);

[0033] Figure 9 for Figure 4 BB cross-sectional view (before the pole is riveted);

[0034] Figure 10 for Figure 3 Schematic diagram of the three-dimensional structure of the middle pole;

[0035] Figure 11 for Figure 3 Top view of the center pole;

[0036] Figure 12 for Figure 3 Schematic diagram of the three-dimensional structure of the middle riveting block;

[0037] Figure 13 for Figure 1 Exploded view of the cover shown.

[0038] Description of reference numerals:

[0039] 1', cover plate body; 2', riveting block; 3', pole; 32', column body;

[0040] 1. Cover plate body; 2. Riveting block; 21. First step; 22. Second step; 3. Pole; 31. Bottom plate; 32. Column; 321. Middle smooth area; 322. Arc area; 323. Pre-rivet groove; 324. Support step; 4. First insulating member; 5. Second insulating member; 6. Sealing member. DETAILED DESCRIPTION

[0041] 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.

[0042] like Figure 1 and Figure 2 As shown, a cover plate using a pole riveting fixation method includes a riveted block 2', a first insulating member, a cover plate body 1', a second insulating member, a pole 3', and a sealing ring. The pole 3' includes a base plate and a column portion 32'. The column portion is generally cylindrical. For cells with narrow and long covers and high current requirements, the narrow width of the cover plate body prevents increasing the current capacity of the 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 plate body, resulting in a narrow and long column portion. This type of pole has a non-circular cross section. When riveting, the riveting punch applies pressure outward from the middle area of ​​the column to expand the material. Since the length of the column is greater than its width, the two ends of the column in the length direction do not expand outward enough, resulting in uneven expansion of the material in various parts of the column in the circumference. After the expansion of the two ends of the column in the length direction, there is a high probability of a gap between the column and the riveted block, and the column cannot be effectively fitted with the riveted block. After laser welding the column and the riveted block, cold welding and unstable internal resistance are likely to occur.

[0043] The following combination Figures 3 to 13 , describing embodiments of the present invention.

[0044] According to an embodiment of the present invention, on the one hand, a pole is provided, which is suitable for use in a cover plate, wherein the cover plate includes a cover plate body 1 and a rivet block 2, wherein the cover plate body 1 is provided with a mounting hole, and the rivet block 2 is provided with a rivet hole, and the rivet block 2 is provided on the outside of the surface of the cover plate body 1 facing the outside of the cover plate; the pole 3 includes a bottom plate 31 and a column portion 32 provided on the bottom plate 31, the column portion 32 is suitable for penetrating the mounting hole and the rivet hole, and the bottom plate 31 is suitable for being provided on the inner side of the other side surface of the cover plate body 1 facing the inside of the cover plate; the column portion 32 is suitable for extending in the same direction as the rivet block 2 and the length of the column portion 32 is greater than its width, and the column portion 32 is provided along the column portion 31. 2, the column portion 32 includes a middle smooth area 321 and curved areas 322 provided at both ends of the middle smooth area 321; a pre-rivet groove 323 extending in the same direction as the column portion 32 is provided on the surface of the column portion 32 facing the outer side of the cover plate; the wall thickness of the column portion 32 at the middle smooth area 321 is greater than the wall thickness of the column portion 32 at the curved areas 322; the wall thickness of the column portion 32 at the position farthest from the middle smooth area 321 of the curved area 322 is a, and the wall thickness of the column portion 32 at the middle smooth area 321 is b, 0.5≤a / b≤0.8, a≥0.5mm, b≥0.5mm.

[0045] In the pole of this structure, a pre-rivet groove 323 extending in the same direction as the pole 32 is provided on the surface of the column portion 32 facing the outer side of the cover plate. The wall thickness of the column portion 32 at the middle smooth area 321 is greater than the wall thickness of the column portion 32 at the arcuate area 322, so that the length of the pre-rivet groove 323 is greater than its width. The shape of the riveting punch corresponds to the pre-rivet groove 323. The dimension of the riveting punch in the length direction of the column portion 32 is greater than the dimension in the width direction of the column portion 32, so that the dimension of the riveting punch in the length direction of the column portion 32 is larger. When the pole 3 is riveted, the riveting punch presses the pre-rivet groove 323 downward to apply force, which can make the material corresponding to the arcuate areas 322 at both ends of the length direction of the column portion 32 expand further outward, so that the expanded column portion 32 is closely attached to the riveting block 2. And the wall thickness a of the column part 32 at the farthest position of the arc-shaped area 322 from the middle smooth area 321 before riveting and the wall thickness b of the column part 32 at the middle smooth area 321 satisfy 0.5≤a / b≤0.8, so that the ratio of the wall thickness a of the column part 32 at the farthest position of the arc-shaped area 322 from the middle smooth area 321 before riveting and the wall thickness b of the column part 32 at the middle smooth area 321 can be controlled within a suitable range, which can avoid a large difference in the wall thickness of the column part 32 in the arc-shaped area 322 and the middle smooth area 321, and ensure that the entire circumference of the column part 32 is evenly expanded. After riveting and swelling, the column portion 32 fits tightly with the riveted block 2, thereby effectively ensuring the reliability of the two after welding and avoiding cold welding; it can also prevent the wall thickness difference between the arc area 322 and the middle smooth area 321 of the column portion 32 from being too small, so that the length of the pre-rivet groove 323 can be significantly greater than its width, and the size of the riveting punch in the length direction of the pre-rivet groove 323 is correspondingly increased, which can make the material corresponding to the arc area 322 at both ends of the length direction of the column portion 32 expand further outward, so that the column portion 32 after swelling is tightly attached to the riveted block 2, thereby effectively ensuring the reliability of the two after welding and avoiding cold welding.

[0046] The arc-shaped areas 322 are provided at both ends of the middle smooth area 321. The side walls of the column portion 32 at the corresponding positions of the arc-shaped areas 322 are arc-shaped surfaces, which smoothly transition to the side walls of the column portion 32 at the middle smooth area 321, so that the side walls of the column portion 32 at the corresponding positions of the arc-shaped areas 322 smoothly transition to the side walls of the column portion 32 at the corresponding positions of the middle smooth area 321. During the riveting process of the pole 3, the column part 32 is punched by the riveting punch to rivet and expand the material. The riveting punch applies pressure to expand the material from the middle area of ​​the column part 32 outward. If there are sharp corners on the side of the column part 32, it is easy to cause uneven expansion at the corners of the column part 32. After the column part 32 is riveted, it cannot be effectively fitted with the riveted block 2. After laser welding the column part 32 and the riveted block 2, it is easy to cause cold welding and unstable internal resistance. The side wall of the column part 32 at the corresponding position of the arc area 322 and the side wall of the column part 32 at the corresponding position of the middle smooth area 321 have a smooth transition. This can ensure that the column part 32 expands evenly at various circumferential positions during riveting, and ensure that various positions of the column part 32 can effectively fit with the riveted block 2. After laser welding the column part 32 and the riveted block 2, the reliability of the welding between the two can be guaranteed, and the stability of the internal resistance and battery operation can be guaranteed.

[0047] like Figure 4 、 Figure 5 、 Figure 10 and Figure 11 As shown, in some embodiments, the arc-shaped area 322 is a semicircular arc, and the side wall of the column portion 32 at the corresponding position of the semicircular arc smoothly transitions to the side wall of the column portion 32 at the corresponding position of the middle smooth area 321. This can ensure that the column portion 32 is evenly expanded at various circumferential positions during riveting, and can ensure the reliability of the welding between the column portion 32 and the riveting block 2, thereby ensuring the internal resistance of the battery and the stability of the battery operation.

[0048] like Figure 4 、 Figure 5 、 Figure 10 and Figure 11As shown, in some embodiments, the middle smooth area 321 is rectangular, and the diameter of the semicircular arc is equal to the width of the middle smooth area 321, that is, the cross-section of the column portion 32 is runway-shaped, wherein the middle area is rectangular and the arc areas 322 at both ends of the middle area are semicircular. Along the circumference of the semicircular arc, from the middle smooth area 321 to the minimum wall thickness of the column part 32, the minimum wall thickness of the column part 32 is the wall thickness of the column part 32 at the farthest position of the arc area 322 from the middle smooth area 321, and the wall thickness of the column part 32 gradually decreases, so as to ensure a smooth transition between the side wall of the column part 32 at the middle smooth area 321 and the side wall of the column part 32 at the semicircular arc area. Correspondingly, the wall thickness of the column part 32 gradually decreases, which can ensure that the column part 32 is evenly expanded at various circumferential positions during riveting; at the same time, the wall thickness at both ends of the column part 32 in the longitudinal direction can be made thinnest, so that the riveting punch can fully expand the material outward at both ends of the column part 32 in the longitudinal direction, which can ensure that the column part 32 is evenly expanded at various circumferential positions during riveting.

[0049] After riveting, the column 32 is held on the riveted block 2 by its deformation zone due to material expansion. The wall thickness of the column 32 outside the pre-riveted groove 323 is related to the connection force when it is hung on the riveted block 2 after material expansion. When the wall thickness of the column 32 is too thin, the pole 3 is easily detached from the riveted block 2 when subjected to external force. In addition, after riveting, the pole 3 needs to be welded to the riveted block 2. The welding head acts on the column 32 outside the pre-riveted groove 323 and the riveted block 2 at the same time. The weld mark has a certain width. When the wall thickness of the column 32 on the side of the pre-riveted groove 323 is too thin, the solid part on the side of the column 32 is small, resulting in insufficient welding space. In order to avoid these problems, in some embodiments, 0.5mm≤a≤3mm, 0.5mm≤b≤3mm, so that the wall thickness of the column portion 32 on the outer side of the pre-rivet groove 323 can be guaranteed. After the column portion 32 of the pole 3 is riveted, the strength of the pole 3 to be retained on the riveting block 2 can be guaranteed, and the pole 3 can be prevented from falling off when the pole 3 is subjected to a force toward the inner side of the cover body 1; at the same time, sufficient welding space can be ensured on the side of the column portion 32, and the weld width and the reliability of the welding of the column portion 32 to the riveting block 2 can be guaranteed; in addition, it can also prevent the wall thickness of the column portion 32 on the side of the pre-rivet groove 323 from being too thick, which makes it difficult to rivet the column portion outward.

[0050] Pole 3 with different a / b, and a and b values ​​were designed. The pole 3 was assembled into a cover plate. The riveting and welding process of the pole 3 was observed and the internal resistance was measured. The test results are shown in Table 1.

[0051] Table 1

[0052]

[0053] It can be seen from Examples 1 to 7 that when a / b satisfies 0.5≤a / b≤0.8, after the column portion 32 is riveted, the column portion 32 in the middle smooth area 321 and the arc-shaped area 322 are riveted evenly, there is no gap between the column portion 32 and the riveting block 2, no cold welding occurs, and the internal resistance of the cover plate meets the requirements; when a≥0.5mm and b≥0.5mm, there is sufficient welding space. It can be seen from comparative example 1 that when a is less than 0.5 mm, due to the thin wall thickness of the column portion 32 at the arcuate area 322, after riveting and expanding the material, the welding space is insufficient, and the internal resistance of the cover plate does not meet the requirements; it can be seen from comparative examples 2 and 3 that when a / b is greater than 0.8, the difference in wall thickness between the column portion 32 in the arcuate area 322 and the middle smooth area 321 is too small. After the column portion 32 is riveted, a gap exists between the column portion 32 and the riveted block 2 at the arcuate area 322, resulting in a cold weld after welding, and the internal resistance does not meet the requirements; it can be seen from comparative example 4 that when a is less than 0.5 mm, b is less than 0.5 mm, and a / b is greater than 0.8, the wall thickness of the column portion 32 around the outer side of the pre-rivet groove 323 is relatively thin. After riveting and expanding the material, the welding There is insufficient space, and after the column part 32 is riveted, there is a gap between the column part 32 and the riveted block 2 at the arc area 322, there is a cold weld, and the internal resistance does not meet the requirements; it can be seen from comparative example 5 that when b is less than 0.5mm and a / b is greater than 0.8, the wall thickness of the column part 32 at the middle smooth area 321 is thinner, and after riveting and expanding the material, there is insufficient welding space, and there is a gap between the column part 32 and the riveted block 2 at the arc area 322 of the column part 32, there is a cold weld, and the internal resistance does not meet the requirements; it can be seen from comparative example 6 that when a / b is less than 0.5, the wall thickness of the column part 32 at the middle smooth area 321 and the arc area 322 is quite different, the riveting of the entire circle of the column part 32 is uneven, there is a cold weld, and the internal resistance does not meet the requirements.

[0054] During riveting, the riveting punch acts on the pre-riveting groove 323. The size of the pre-riveting groove 323 determines the size of the end of the riveting punch. If the width of the pre-riveting groove 323 is too small, the width of the riveting punch will be correspondingly small. At this time, it is difficult to ensure the strength of the riveting punch. The riveting punch itself is weak and it is difficult to squeeze the column part 32 to expand the material. In order to prevent this problem, Figure 11 As shown, in some embodiments, the width of the pre-rivet groove 323 is W1, and the width of the column portion 32 on the circumferential outer side of the rivet groove is W2, 2mm≤W1<W2-b, and the units of W1 and W2 are mm. W1≥2mm, which can ensure the lower limit of the width of the pre-rivet groove 323, thereby ensuring the width of the riveting punch, and further ensuring the strength of the riveting punch and the riveting effect. The length of the pre-rivet groove 323 is greater than its width, and the lower limit of the width of the pre-rivet groove 323 is ensured, thereby ensuring the lower limit of the length of the pre-rivet groove 323, thereby ensuring the width and length of the riveting punch, thereby ensuring the strength of the riveting punch and the riveting effect.

[0055] like Figures 7 to 9As shown, in some embodiments, the cross section of the pre-rivet groove 323 is rectangular, and its bottom is flat. A support step 324 is provided on the circumference of the side wall of the column portion 32, and the side surface of the rivet block 2 facing the inner side of the cover plate abuts on the support step 324; the bottom of the pre-rivet groove 323 is flush with the support step 324 or the bottom of the pre-rivet groove is arranged relative to the support step 324 and close to the notch of the pre-rivet groove 323. That is, Figure 8 In the illustrated state, the bottom of the pre-riveted groove 323 is no lower than the support step 324. This prevents the pre-riveted groove 323 from being too deep and affecting its strength. This ensures the connection strength between the column portion 32 and the riveted block 2 after riveting, and prevents the terminal 3 from falling off the riveted block 2 when subjected to external forces. When riveting the terminal 3, the riveted block 2 is susceptible to deformation due to the downward force of the riveting punch. The support step 324 supports the riveted block 2, alleviating the degree of collapse in the central area of ​​the riveted block 2 and thereby improving the flatness of the riveted block 2.

[0056] According to an embodiment of the present invention, on the other hand, a cover plate is provided. The cover plate includes a cover plate body 1 , a riveting block 2 and the pole 3 of the above embodiment.

[0057] The cover body 1 is provided with a mounting hole; the rivet block 2 is provided with a rivet hole and is arranged on the outside of the cover body's surface facing the outside of the cover; the column portion 32 is penetrated by the mounting hole and the rivet hole, and the bottom plate 31 is arranged on the inner side of the other side surface of the cover body 1 facing the inside of the cover; the column portion extends in the same direction as the rivet block and the length of the column portion is greater than its width; before the pole is riveted, the wall thickness of the column portion at the farthest position of the arc area from the middle smooth area is a, and the wall thickness of the column portion at the middle smooth area is b.

[0058] The cover plate of this structure has a pre-rivet groove 323 extending in the same direction as the column portion 32 on one side surface of the column portion 32 facing the outer side of the cover plate. The wall thickness of the column portion 32 at the middle smooth area 321 is greater than the wall thickness of the column portion 32 at the arc area 322, so that the length of the pre-rivet groove 323 is greater than its width. The shape of the riveting punch corresponds to the pre-rivet groove 323. The dimension of the riveting punch in the length direction of the column portion 32 is greater than the dimension in the width direction of the column portion 32, so that the dimension of the riveting punch in the length direction of the column portion 32 is larger. When the pole 3 is riveted, the riveting punch presses the pre-rivet groove 323 downward to apply force, which can make the material corresponding to the arc areas 322 at both ends of the length direction of the column portion 32 expand further outward, so that the expanded column portion 32 is tightly attached to the riveting block 2. And the wall thickness a of the column part 32 at the farthest position of the arc-shaped area 322 from the middle smooth area 321 before riveting and the wall thickness b of the column part 32 at the middle smooth area 321 satisfy 0.5≤a / b≤0.8, so that the ratio of the wall thickness a of the column part 32 at the farthest position of the arc-shaped area 322 from the middle smooth area 321 before riveting and the wall thickness b of the column part 32 at the middle smooth area 321 can be controlled within a suitable range, which can avoid a large difference in the wall thickness of the column part 32 in the arc-shaped area 322 and the middle smooth area 321, and ensure that the entire circumference of the column part 32 is evenly expanded. After riveting and swelling, the column portion 32 fits tightly with the riveted block 2, thereby effectively ensuring the reliability of the two after welding and avoiding cold welding; it can also prevent the wall thickness difference between the arc area 322 and the middle smooth area 321 of the column portion 32 from being too small, so that the length of the pre-rivet groove 323 can be significantly greater than its width, and the size of the riveting punch in the length direction of the pre-rivet groove 323 is correspondingly increased, which can make the material corresponding to the arc area 322 at both ends of the length direction of the column portion 32 expand further outward, so that the column portion 32 after swelling is tightly attached to the riveted block 2, thereby effectively ensuring the reliability of the two after welding and avoiding cold welding.

[0059] like Figure 8 and Figure 12As shown, the inner wall of the rivet hole is provided with a first step 21 and a second step 22 located on the side of the first step 21 near the rivet block 2 facing the outside of the cover plate. The deformed area of ​​the column portion 32 after riveting abuts the stepped surface of the first step 21 on the side facing the inside of the cover plate, and the circumferential sidewall of the column portion 32 abuts the vertical wall area between the two steps. The height between the first step 21 and the second step 22 is h1, and h1 is ≥ 0.8 mm. After riveting, the pole 3 is laser welded to the rivet block 2. During welding, heat acts on the stepped surface of the second step 22 and the side of the column portion 32 facing the outside of the cover plate. If the height h1 between the two steps is too small, the welding heat can easily penetrate the area between the two steps and melt the first step 21, which will affect the strength of the column portion 32 attached to the rivet block 2 after riveting. At the same time, if the height between the two steps is too small, the support force is insufficient, which will also affect the connection strength between the pole 3 and the rivet block 2. Therefore, in this embodiment, h1 is set to be ≥ 0.8 mm. This setting can ensure that there is a sufficient height between the two steps, which can prevent the welding heat from melting the first step 21 during laser welding. At the same time, it can ensure the supporting strength of the riveted block 2, so that the pole 3 is stably and firmly maintained on the riveted block 2 after connection.

[0060] In some embodiments, the first step 21 and the second step 22 have the same width at all locations along their respective circumferences.

[0061] After the column part 32 is riveted, its expanded deformation area needs to fill the step surface of the first step 21, so that the circumferential side wall of the column part 32 abuts the vertical wall area between the two step surfaces of the first step 21 and the second step 22, ensuring the fit between the column part 32 and the riveting block 2, thereby preventing the occurrence of cold welds after welding. If the step surface of the first step 21 is wider, the distance between the circumferential side wall of the column part 32 and the vertical wall of the riveting block 2 before riveting is farther, and it is difficult for the column part 32 to fill the first step 21 after the material is expanded, resulting in a gap between the circumferential side wall of the column part 32 and the vertical wall between the two steps of the riveting block 2, which results in cold welds between the column part 32 and the riveting block 2 after welding. In order to avoid this problem, as Figure 8 As shown, in some embodiments, in a plane parallel to the plane where the cover body is located, the width of the step surface of the first step 21 is c, c≤0.5mm. This setting can prevent the step surface of the first step 21 from being too wide, and ensure that the circumferential side wall of the column portion 32 can fit on the vertical wall between the two steps of the riveted block 2 after the material is expanded, thereby ensuring the reliability of the welding between the pole 3 and the riveted block 2 after welding, and ensuring the stability of the internal resistance of the battery cell and the battery performance.

[0062] like Figure 6 and Figure 7As shown, in some embodiments, after riveting, the side surface of the column portion 32 facing the outside of the cover plate is flush with the step surface of the second step 22; the width of the step surface of the second step 22 is d, and the height of the second step 22 is h2, d ≥ 0.5mm, h2 ≥ 0.2mm. After the column portion 32 is riveted and expanded, it is welded to the riveting block 2. The weld mark has a certain thickness and width, and the groove formed at the second step 22 is used to accommodate the weld mark. d ≥ 0.5mm, h2 ≥ 0.2mm, so that the height and width of the second step 22 can be guaranteed, so that it has enough space to accommodate the weld mark, which can effectively prevent the weld mark from leaking out, thereby ensuring the appearance of the battery cell, and at the same time, it can ensure the flatness of the side surface of the riveting block 2 facing the outside of the cover plate, without affecting the subsequent welding of the riveting block 2 and the busbar.

[0063] In some embodiments, as Figures 6 to 9 and Figure 13 As shown, the cover plate further includes a first insulating member 4, a second insulating member 5, and a sealing member 6. The first insulating member 4 is provided on a side surface of the cover plate body 1 facing the outside of the cover plate; the rivet block 2 is provided on a side surface of the first insulating member 4 facing the outside of the cover plate; the second insulating member 5 is provided on a side surface of the cover plate body 1 facing the inside of the cover plate; the bottom plate 31 is provided on the inner side of the side surface of the second insulating member 5 facing the inside of the cover plate; the sealing member 6 is provided between the cover plate body 1 and the pole 3, with the side surface of the bottom plate 31 facing the outside of the cover plate abutting against the sealing member 6. 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.

[0064] 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.

[0065] According to an embodiment of the present invention, on the other hand, a battery cell is provided, comprising a shell and a cover according to any one of the above embodiments, wherein the shell is provided with an opening, and the cover is provided on the opening.

[0066] In the battery cell of this structure, a pre-rivet groove 323 extending in the same direction as the column portion 32 is provided on the surface of the column portion 32 of the cover plate facing the outside of the cover plate. The wall thickness of the column portion 32 at the middle smooth area 321 is greater than the wall thickness of the column portion 32 at the arc area 322, so that the length of the pre-rivet groove 323 is greater than its width. The shape of the riveting punch corresponds to the pre-rivet groove 323. The dimension of the riveting punch in the length direction of the column portion 32 is greater than the dimension in the width direction of the column portion 32, so that the dimension of the riveting punch in the length direction of the column portion 32 is larger. When the pole 3 is riveted, the riveting punch presses the pre-rivet groove 323 downward to apply force, which can make the material corresponding to the arc areas 322 at both ends of the length direction of the column portion 32 expand further outward, so that the expanded column portion 32 is tightly attached to the riveting block 2. And the wall thickness a of the column part 32 at the farthest position of the arc-shaped area 322 from the middle smooth area 321 before riveting and the wall thickness b of the column part 32 at the middle smooth area 321 satisfy 0.5≤a / b≤0.8, so that the ratio of the wall thickness a of the column part 32 at the farthest position of the arc-shaped area 322 from the middle smooth area 321 before riveting and the wall thickness b of the column part 32 at the middle smooth area 321 can be controlled within a suitable range, which can avoid a large difference in the wall thickness of the column part 32 in the arc-shaped area 322 and the middle smooth area 321, and can ensure that the whole circle of the column circumference is evenly expanded, so that the riveting can be smooth. After the material is expanded, the column portion 32 fits tightly with the riveted block 2, thereby effectively ensuring the reliability of the welding between the two and avoiding cold welding; it can also prevent the wall thickness difference between the arc area 322 and the middle smooth area 321 of the column portion 32 from being too small, so that the length of the pre-rivet groove 323 can be significantly greater than its width, and the size of the rivet punch in the length direction of the pre-rivet groove 323 is correspondingly increased, which can make the material corresponding to the arc area 322 at both ends of the length direction of the column portion 32 expand further outward, so that the column portion 32 after the material is expanded is tightly attached to the riveted block 2, thereby effectively ensuring the reliability of the welding between the two and avoiding cold welding.

[0067] 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.

[0068] 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.

[0069] 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 pole, characterized in that: Suitable for use in a cover plate, the cover plate includes a cover plate body and a rivet block, the cover plate body is provided with a mounting hole, the rivet block is provided with a rivet hole, and the rivet block is provided on the outside of the side surface of the cover plate body facing the outside of the cover plate; the pole includes: The bottom plate and a column portion provided on the bottom plate, the column portion is suitable for passing through the mounting hole and the rivet hole, and the bottom plate is suitable for being provided on the inner side of the other side surface of the cover plate body facing the inner side of the cover plate; the column portion is suitable for extending in the same direction as the rivet block and the length of the column portion is greater than its width, and along the length direction of the cross section of the column portion, the column portion includes a middle smooth area and arc-shaped areas provided at both ends of the middle smooth area; a pre-rivet groove extending in the same direction as the column portion is provided on the side surface of the column portion facing the outer side of the cover plate, and the wall thickness of the column portion at the middle smooth area is greater than the wall thickness of the column portion at the arc-shaped area; the wall thickness of the column portion at the farthest position of the arc-shaped area from the middle smooth area is a, and the wall thickness of the column portion at the middle smooth area is b, 0.5≤a / b≤0.8, and the units of a and b are mm.

2. The pole according to claim 1, characterized in that The arc-shaped area is a semicircular arc, and the side wall of the column portion at a position corresponding to the semicircular arc smoothly transitions to the side wall of the column portion at a position corresponding to the middle smooth area.

3. The pole according to claim 2, characterized in that The central smooth area is rectangular, and the diameter of the semicircular arc is equal to the width of the central smooth area; along the circumference of the semicircular arc, from the central smooth area to the minimum wall thickness of the column part, the wall thickness of the column part gradually decreases.

4. The pole according to any one of claims 1 to 3, characterized in that 0.5mm≤a≤3mm, 0.5mm≤b≤3mm.

5. The pole according to claim 3, characterized in that: The width of the pre-rivet groove is W1, and the width of the column portion on the circumferential outer side of the riveting groove is W2, 2mm≤W1<W2-b, and the units of W1 and W2 are mm.

6. The pole according to any one of claims 1 to 4, characterized in that A support step is provided on the circumference of the side wall of the column portion, and the side surface of the rivet block facing the inner side of the cover plate is suitable for abutting against the support step; the bottom of the pre-rivet groove is flush with the support step or the bottom of the pre-rivet groove is arranged relative to the support step and close to the notch of the pre-rivet groove.

7. A cover plate, characterized in that: include: The cover body is provided with a mounting hole; a riveting block, provided with a riveting hole and arranged on the outer side of the cover plate body facing the outer side of the cover plate; The pole according to any one of claims 1 to 6, wherein the mounting hole and the rivet hole are passed through the column portion, and the bottom plate is arranged on the inner side of the other side surface of the cover body facing the inner side of the cover plate; the column portion extends in the same direction as the rivet block and the length of the column portion is greater than the width thereof; before the pole is riveted, the wall thickness of the column portion at the farthest position of the arc-shaped area from the middle smooth area is a, and the wall thickness of the column portion at the middle smooth area is b.

8. The cover plate according to claim 7, wherein: The inner wall of the rivet hole is provided with a first step and a second step located on a side surface of the first step close to the rivet block facing the outer side of the cover plate; the deformation zone of the column portion after riveting is abutted against the step surface of the first step on a side surface facing the inner side of the cover plate body; the height between the first step and the second step is h1, and h1 ≥ 0.8 mm.

9. The cover plate according to claim 8, characterized in that: In a plane parallel to the plane where the cover plate body is located, the width of the step surface of the first step is c, and c≤0.5 mm.

10. A battery cell, characterized in that: The invention comprises a shell and the cover plate according to any one of claims 7 to 9, wherein the shell is provided with an opening, and the cover plate is arranged on the opening.

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