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 is provided with a supporting step on the peripheral side wall of a post body part of a post. The length between one end of the riveting block and the corresponding inner side wall of the riveting hole is M, the lengths of the cylinder portions, facing the inner side of the cover plate and the outer side of the cover plate, of the supporting step are L1 and L2 respectively, M, L1 and L2 meet the requirement that M / ((L2-L1) / 2) is smaller than or equal to 150, and the ratio of the length of the single-side riveting block to the average width of the supporting step is controlled within a proper range according to the formula. The riveting block can prevent the single side length of the riveting block from being too long or the width of the supporting step from being narrow, can guarantee the supporting effect of the supporting step on the middle area of the riveting block, can prevent the middle area of the riveting block from collapsing and the two ends of the riveting block in the length direction from tilting when the pole is riveted, and can effectively guarantee the flatness of the riveting block. The flatness of the riveting block can be controlled within a required range, and the cover plate is assembled on the battery cell, so that the sealing performance and the safety performance of the battery cell can be effectively ensured.

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 consists of a rivet block, a first insulating member, a cover plate body, a second insulating member, a pole, and a sealing ring. The pole base and the rivet block hold the cover plate components in place. The top of the pole is riveted to the rivet block, and the connection between the pole and the rivet block is reinforced by laser welding. For narrow, long cover plates, the rivet force applied during pole riveting causes the rivet block to warp at both ends, resulting in unsatisfactory flatness. Summary of the Invention

[0003] 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 cover plate warps at both ends of the riveting block in the length direction during riveting, thereby affecting its flatness.

[0004] In a first aspect, the present invention provides a cover plate, comprising:

[0005] Cover plate body;

[0006] A first insulating member is provided on a surface of the cover body facing the outer side of the cover;

[0007] a rivet block having a rivet hole and disposed on the first insulating member, the rivet block extending in the same direction as the cover plate body and having a length greater than a width; along the length direction of the rivet block, a length M between one end of the rivet block and a corresponding inner side wall of the rivet hole;

[0008] a second insulating member, provided on the other side surface of the cover body facing the inner side of the cover;

[0009] A pole comprises a base plate and a column portion provided on the base plate, wherein the base plate is provided on the inner side of a surface of the second insulating member facing the inner side of the cover plate; the column portion extends in the same direction as the rivet block and its length is greater than its width, and a supporting step is provided on the peripheral side wall of the column portion; the column portion passes through the second insulating member, the cover plate body, the first insulating member and the rivet block, and a surface of the rivet block facing the inner side of the cover plate abuts against the supporting step; the length of the column portion located on the side of the support step facing the outer side of the cover plate is L1, and the length of the column portion located on the side of the support step facing the inner side of the cover plate is L2, 1.5≤M / ((L2-L1) / 2)≤150, and the units of M, L1 and L2 are mm.

[0010] Beneficial effect: The cover plate of this structure is provided with a support step on the peripheral side wall of the column part of the pole, and the surface of the rivet block facing the inner side of the cover plate abuts against the support step. When the pole is riveted, the rivet block is subjected to the downward force of the riveting punch, and the support step supports the rivet block, which alleviates the degree of collapse of the middle area of ​​the rivet block to a certain extent. The length of the solid part of the rivet block on the side of the riveted hole is M, and the lengths of the column part located on the inside and outside of the support step are L1 and L2 respectively. L2-L1 is the total width of the support steps on both sides of the length direction of the column part, (L2-L1) / 2 is the average width of the support steps on one side of the length direction of the column part, and M, L1 and L2 satisfy 1.5≤M / ((L2-L1) / 2)≤150. By using this formula, the ratio of the length of the unilateral rivet block to the average width of the support step is controlled within an appropriate range, which can avoid the rivet block from being too long on one side or the support step from being too narrow, and can ensure the support effect of the support step on the middle area of ​​the rivet block, thereby avoiding When the rivet-free block is riveted to the pole, the middle area sags and the two ends in the length direction warp, thereby effectively ensuring the flatness of the rivet block and controlling the flatness of the rivet block within the required range. The cover plate is assembled on the battery cell, which can effectively ensure the sealing and safety performance of the battery cell; the column part passes through the pole hole on the cover plate body, 1.5≤M / ((L2-L1) / 2), which can prevent the single side length of the rivet block from being less than the width of the support step, and can ensure that the end of the rivet block away from the pole hole is located on the cover plate body on the circumferential outside of the pole hole, so that the rivet block can be stably maintained on the cover plate body, and can prevent the rivet block from falling off from the pole hole.

[0011] In an optional embodiment, the widths of the support steps on both sides of the column portion in the length direction are the same.

[0012] Beneficial Effect: The widths of the support steps on both sides of the column lengthwise are the same, allowing them to evenly and stably support the rivet block from both sides along the lengthwise direction of the column, ensuring the flatness of the rivet block along both sides of the lengthwise direction of the rivet hole. In this case, (L2-L1) / 2 is the width of the support step on one side of the column lengthwise direction, and M, L1, and L2 satisfy 1.5≤M / ((L2-L1) / 2)≤150. This formula controls the ratio of the length of the unilateral rivet block to the width of the unilateral support step within an appropriate range, ensuring the support effect of the support step on the central area of ​​the rivet block.

[0013] In an optional embodiment, 0.2 mm ≤ (L2-L1) / 2 ≤ 10 mm.

[0014] Beneficial effect: 0.2mm≤(L2-L1) / 2. This setting can ensure that the support steps on the side of the length direction of the column part have sufficient width, which can ensure the supporting effect of the support steps on the riveting block; at the same time, it can avoid the support step size being too small, resulting in unclear step features, and the step width being too small to be convenient for forming the column part. Ensuring the minimum width of the support step is conducive to forming the column part.

[0015] The width of the support step on the side of the column in the longitudinal direction satisfies (L2-L1) / 2≤10mm, which can prevent the width of the support step on the side of the column in the longitudinal direction from being too large, making it convenient to form the pole through a relatively low-cost stamping or pier pressing process.

[0016] In an optional embodiment, along the width direction of the cover plate, the width of the column portion located on the side of the support step facing the outer side of the cover plate is W1, and the width of the column portion located on the side of the support step facing the inner side of the cover plate is W2. The widths of the support steps on both sides of the width direction of the column portion are the same, 0.2mm≤(W2-W1) / 2≤10mm, and the units of W1 and W2 are mm.

[0017] Beneficial Effects: 0.2mm≤(W2-W1) / 2≤10mm. This configuration ensures that the support steps on the width side of the column body are sufficiently wide, ensuring the support effect of the support steps on the riveted block. It also prevents the support steps from being too small, resulting in unclear step features, which facilitates the molding of the column body. It also prevents the support steps on the width side of the column body from being too wide, facilitating the relatively low-cost stamping or piercing process for forming the pole.

[0018] In an optional embodiment, (W2-W1) / 2≤(L2-L1) / 2.

[0019] Beneficial effect: In this way, the support effect on the length direction of the rivet block can be improved by lengthening the width of the support step in the length direction of the column part, thereby effectively preventing the two ends of the rivet block from warping in the length direction.

[0020] In an optional embodiment, 5mm≤M≤50mm.

[0021] Beneficial Effect: This allows the upper limit of the unilateral length of the riveted block to be controlled within an appropriate range, preventing deformation of the riveted block due to its own excessive length. It also ensures a minimum unilateral length of the riveted block, thereby ensuring a lower limit of the overall length of the riveted block, and thus ensuring the area of ​​the riveted block. This, in turn, ensures the welding area between the riveted block and the battery pack tab, thereby increasing the welding area between the riveted block and the tab, and ensuring connection reliability and current capacity.

[0022] In an optional embodiment, the cross-section of the column portion is in the shape of an athletic track or an ellipse.

[0023] Beneficial effects: This can avoid the appearance of sharp corners on the side walls of the column, ensure that the pole is evenly expanded at all positions during riveting, and ensure that all positions of the column can effectively fit with the riveting block. After laser welding the column and the riveting block, the reliability of the welding between the two can be guaranteed, which can ensure the internal resistance of the battery and the stability of the battery operation.

[0024] In an optional embodiment, before riveting, a pre-rivet groove is provided on a surface of the column portion facing the outer side of the cover plate, and the long side of the pre-rivet groove extends in the same direction as the long side of the column portion.

[0025] 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.

[0026] 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 is not further described here. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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.

[0028] Figure 1 This is a schematic diagram of the three-dimensional structure of a cover plate according to an embodiment of the present invention;

[0029] Figure 2 for Figure 1 a top view of the cover plate shown;

[0030] Figure 3 for Figure 2 AA sectional view;

[0031] Figure 4 for Figure 3 A partial enlarged view of part A in the middle;

[0032] Figure 5 for Figure 2 BB cross-sectional view;

[0033] Figure 6 for Figure 1 An exploded view of the cover plate is shown;

[0034] Figure 7 for Figure 1 Schematic diagram of the three-dimensional structure of the middle pole;

[0035] Figure 8 for Figure 1 Top view of the center pole.

[0036] Description of reference numerals:

[0037] 1. Cover plate body; 2. First insulating member; 3. Riveted block; 4. Second insulating member; 5. Pole; 51. Bottom plate; 52. Column body; 521. Support step; 522. Pre-rivet groove; 6. Sealing member. DETAILED DESCRIPTION

[0038] 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.

[0039] The cover plate in the related art includes a riveted block, a first insulating member, a cover plate body, a second insulating member, a pole and a sealing ring and other structures. The pole includes a base plate and a column portion. The column portion is generally cylindrical. For a battery cell with a narrow and long cover plate and a large overcurrent requirement, since the width of the cover plate body is narrow, it is impossible to increase the overcurrent capacity of the battery cell by increasing the diameter of the cylindrical column portion. It can only be formed by increasing the size of the column portion in the length direction of the cover plate body. A narrow and long column portion is formed. For the narrow and long cover plate and column portion, the riveted block is also narrow and long. When the cover plate is assembled, the column portion passes through the second insulating member, the cover plate body, the first insulating member and the riveted block. The pole base plate and the riveted block clamp the cover plate components between the two. The top of the pole is riveted to the riveted block, and then the connection between the pole and the riveted block is reinforced by laser welding. The inventors have found that during the riveting process of the pole, under the action of the downward riveting force, the two ends of the riveted block in the length direction will warp, resulting in unqualified flatness of the riveted block.

[0040] The following combination Figures 1 to 8 , describing embodiments of the present invention.

[0041] According to an embodiment of the present invention, in one aspect, a cover plate is provided, including a cover plate body 1 , a first insulating member 2 , a rivet block 3 , a second insulating member 4 and a pole 5 .

[0042] Among them, the first insulating member 2 is provided on the side surface of the cover body 1 facing the outside of the cover; the rivet block 3 is provided with a rivet hole and is provided on the first insulating member 2, the rivet block 3 extends in the same direction as the cover body 1 and the length of the rivet block 3 is greater than its width; along the length direction of the rivet block 3, the length between one end of the rivet block 3 and the corresponding inner side wall of the rivet hole is M; the second insulating member 4 is provided on the other side surface of the cover body 1 facing the inside of the cover; the pole 5 includes a bottom plate 51 and a column portion 52 provided on the bottom plate 51, the bottom plate 51 is provided on the inner side of the side surface of the second insulating member 4 facing the inside of the cover, and the column portion 52 is connected to the rivet hole. The connecting block 3 extends in the same direction and its length is greater than its width. A support step 521 is provided on the peripheral side wall of the column portion 52 in the length direction; the column portion 52 passes through the second insulating member 4, the cover body 1, the first insulating member 2 and the rivet block 3, and the side surface of the rivet block 3 facing the inner side of the cover is abutted on the support step 521; the length of the column portion 52 located on the side of the support step 521 facing the outer side of the cover is L1, and the length of the column portion 52 located on the side of the support step 521 facing the inner side of the cover is L2, 1.5≤M / ((L2-L1) / 2)≤150, and the units of M, L1 and L2 are mm.

[0043] The cover plate of this structure is provided with a support step 521 on the peripheral side wall of the column portion 52 of the pole 5. The side surface of the rivet block 3 facing the inner side of the cover plate abuts against the support step 521. When riveting the pole 5, the rivet block 3 is subjected to the downward force of the riveting punch. The support step 521 supports the rivet block 3, which to a certain extent alleviates the degree of collapse of the middle area of ​​the rivet block 3. The length of the solid part of the rivet block 3 on the side of the rivet hole is M, the lengths of the column portion 52 located on the inner and outer sides of the support step 521 are L1 and L2 respectively, L2-L1 is the total width of the support steps 521 on both sides of the length direction of the column portion 52, (L2-L1) / 2 is the average width of the support step 521 on one side of the length direction of the column portion 52, M, L1 and L2 satisfy 1.5≤M / ((L2-L1) / 2)≤150, and this formula is used to control the ratio of the length of the unilateral rivet block 3 to the average width of the support step 521 within an appropriate range, which can avoid the unilateral length of the rivet block 3 being too long or the width of the support step 521 being too narrow, and can ensure the supporting effect of the support step 521 on the middle area of ​​the rivet block 3. The result is that the middle area of ​​the rivet block 3 can be prevented from sagging and the two ends in the length direction from warping when the rivet block 3 is riveted on the pole 5, thereby effectively ensuring the flatness of the rivet block 3 and controlling the flatness of the rivet block 3 within the required range. The cover plate is assembled on the battery cell, which can effectively ensure the sealing and safety performance of the battery cell; the column portion 52 passes through the pole hole on the cover plate body 1, 1.5≤M / ((L2-L1) / 2), which can prevent the single side length of the rivet block 3 from being less than the width of the support step 521, and can ensure that the end of the rivet block 3 away from the pole hole is located on the cover plate body on the circumferential outside of the pole hole, so that the rivet block 3 can be stably maintained on the cover plate body 1, and can prevent the rivet block 3 from falling off from the pole hole.

[0044] like Figure 4 、 Figure 7 and Figure 8 As shown, in some embodiments, the widths of the support steps 521 on both sides of the lengthwise direction of the column portion 52 are the same, so that the support steps 521 on both sides can evenly and stably support the rivet block 3 from both sides of the lengthwise direction of the column portion 52, thereby ensuring the flatness of the rivet block 3 on both sides of the lengthwise direction of the rivet hole. In this case, (L2-L1) / 2 is the width of the support step 521 on one side of the column portion 52 in the lengthwise direction, and M, L1, and L2 satisfy 1.5≤M / ((L2-L1) / 2)≤150. By using this formula, the ratio of the length of the unilateral rivet block 3 to the width of the unilateral support step 521 is controlled within an appropriate range, thereby ensuring the support effect of the support step 521 on the central area of ​​the rivet block 3.

[0045] Riveted blocks 3 with different M and poles 5 with different (L2-L1) / 2 were designed. The riveted blocks 3 and poles 5 were assembled into a cover plate. After the poles 5 were riveted, the flatness of the riveted blocks 3 was measured. The test results are shown in Table 1.

[0046] Table 1

[0047] Example (L2-L1) / 2 / mm M / mm M / ((L2-L1) / 2) result Example 1 8 16 2 Flatness 0.077mm, meets the requirements Example 2 7 21 3 Flatness 0.082mm, meets the requirements Example 3 6 30 5 Flatness 0.087mm, meets the requirements Example 4 5 30 6 Flatness 0.093mm, meeting the requirements Example 5 4 36 9 Flatness 0.101mm, meets the requirements Example 6 3 39 13 Flatness 0.117mm, meets the requirements Example 7 2 48 24 Flatness 0.128mm, meets the requirements 8 1 50 50 Flatness 0.167mm, meets the requirements Example 9 0.5 30 60 Flatness 0.175mm, meets the requirements Example 10 0.3 33 110 Flatness 0.189mm, meets the requirements Example 11 0.2 5 25 Flatness 0.131mm, meets the requirements Example 12 0.2 20 100 Flatness 0.183mm, meets the requirements Example 13 0.2 30 150 Flatness 0.196mm, meets the requirements Comparative Example 1 0.2 32 160 Flatness 0.213mm, NG Comparative Example 2 0.2 34 170 Flatness 0.289mm, NG

[0048] The flatness of the cell riveted block 3 is required to be less than 0.2 mm. As shown in Examples 1 to 13 in Table 1, when M, L1, and L2 satisfy 1.5 ≤ M / ((L2-L1) / 2) ≤ 150, the flatness of the riveted block 3 after the pole 5 is riveted is less than 0.2 mm, and the flatness of the riveted block 3 meets the requirement. As shown in Comparative Examples 1 and 2 in Table 1, when M / ((L2-L1) / 2) > 150, the flatness of the riveted block 3 is greater than 0.2 mm, exceeding the required value and resulting in unqualified products.

[0049] The first insulating member 2, the cover body 1, and the second insulating member 4 are each provided with a pole hole. The column portion 52 sequentially passes through the pole holes in the second insulating member 4, the cover body 1, and the first insulating member 2, as well as the riveted hole in the riveted block 3. The length M of the solid portion of the riveted block 3 on the side of the riveted hole must be greater than the width of the support steps 521 on both sides of the length of the column portion 52. The value of M ensures that the ends of the riveted block 3 in the length direction are located circumferentially outside the pole hole and that the orthographic projection area of ​​the riveted block 3 on the cover body 1 is sufficient. This ensures that the cover body 1 supports the riveted block 3 effectively and prevents the central area of ​​the riveted block 3 from collapsing toward the pole hole or leaking out of the pole hole.

[0050] In some optional embodiments, such as Figure 4 and Figure 8 As shown, the width of the support step 521 on the side of the length direction of the column portion 52 satisfies 0.2mm≤(L2-L1) / 2≤10mm. 0.2mm≤(L2-L1) / 2 ensures that the support step 521 on the side of the length direction of the column portion 52 has sufficient width to ensure the support effect of the support step 521 on the riveting block 3. At the same time, it avoids the support step 521 being too small, resulting in an unclear step feature, and the step width being too small to facilitate the formation of the column portion 52. Ensuring the minimum width of the support step 521 is conducive to the formation of the column portion 52.

[0051] The body 52 of the pole 5 is typically formed by stamping or pressing. If the width of the support step 521 is too large, the body 52 will be difficult to form by stamping or pressing. If turning is used, the production cost of the pole 5 will increase. To avoid these problems, the width of the support step 521 on the longitudinal side of the body 52 satisfies (L2-L1) / 2≤10mm. This prevents the width of the support step 521 on the longitudinal side of the body 52 from being too large, facilitating the relatively low-cost stamping or pressing process for forming the pole 5.

[0052] The poles 5 with different (L2-L1) / 2 are designed and formed by stamping or pier pressing. The difficulty of the manufacturing process of the poles 5 is shown in Table 2.

[0053] Table 2

[0054]

[0055] It can be seen from Examples 1 to 4 in Table 2 that when the size of the support step 521 satisfies 0.2 mm ≤ (L2 - L1) / 2 ≤ 10 mm, it is convenient to form the pole 5 by a stamping or pier pressing process; it can be seen from Comparative Example 1 in Table 2 that when (L2 - L1) / 2 is less than 0.2 mm, the width of the support step 521 in the length direction of the column portion 52 is too small, resulting in difficulty in forming the pole 5; it can be seen from Comparative Example 2 in Table 2 that when (L2 - L1) / 2 is greater than 10 mm, the width of the support step 521 in the length direction of the column portion 52 is too large, making it difficult to form the pole 5 by a stamping or pier pressing process.

[0056] like Figure 7 and Figure 8 As shown, in some embodiments, along the width direction of the cover plate, the width of the column portion 52 located on the side of the support step 521 facing the outer side of the cover plate is W1, and the width of the column portion 52 located on the side of the support step 521 facing the inner side 1 of the cover plate is W2. The widths of the support steps 521 on both sides of the width direction of the column portion 52 are the same, 0.2mm≤(W2-W1) / 2≤10mm, and the units of W1 and W2 are mm. The support steps 521 are arranged around the side walls of the column portion 52, so that the column portion 52 has support steps 521 of a certain width in both the length and width directions. The support steps 521 can support the rivet block 3 in both the length and width directions, thereby effectively preventing the central area of ​​the rivet block 3 from collapsing. W2-W1 is the total width of the support steps 521 on both sides of the column portion 52 in the width direction, (W2-W1) / 2 is the width of the support step 521 on one side of the column portion 52 in the width direction, and 0.2mm≤(W2-W1) / 2≤10mm. This configuration ensures that the support steps 521 on the sides of the column portion 52 in the width direction have sufficient width to ensure the support effect of the support steps 521 on the rivet block 3; at the same time, it prevents the support steps 521 from being too small, resulting in unclear step features, which is conducive to forming the column portion 52. At the same time, it prevents the width of the support steps 521 on the sides of the column portion 52 in the width direction from being too large, facilitating the forming of the pole 5 through a relatively low-cost stamping or piercing process.

[0057] In some embodiments, (W2-W1) / 2≤(L2-L1) / 2, that is, the width of the support step 521 in the length direction of the column portion 52 is greater than or equal to the width of the support step 521 in the width direction of the column portion 52. Because the length of the rivet block 3 is greater than its width, the ends of the rivet block 3 in the length direction are more likely to warp than the ends of the width direction. Therefore, (W2-W1) / 2≤(L2-L1) / 2 is set. In this way, the support effect of the rivet block 3 in the length direction can be improved by lengthening the width of the support step 521 in the length direction of the column portion 52, thereby effectively preventing the ends of the rivet block 3 in the length direction from warping.

[0058] The rivet block 3 needs to go through cleaning, polishing and drying processes after production. The rivet block 3 is narrow and long. When the length M of its single side is long, the rivet block 3 itself is prone to warping, deformation or twisting during the processing of each process and the flow of each process. The cover plate is assembled into a battery cell, and multiple battery cells are assembled into a battery pack. Adjacent battery cells are connected by tabs, and the tabs are welded to the rivet blocks 3 of adjacent battery cells. For the narrow and long cover plate, the rivet block 3 is narrow. If the length of the rivet block 3 is also relatively small, the surface area of ​​the rivet block 3 is small, and it is difficult to ensure the welding area between it and the tab, and it is difficult to ensure the connection strength between the rivet block 3 and the tab, which will also affect the current flow capacity. In order to avoid these problems, such as Figure 4 As shown, in some embodiments, the length M of the rivet block 3 on one side of the rivet hole satisfies 5mm≤M≤50mm. M≤50mm can control the upper limit of the single-side length of the rivet block 3 within an appropriate range, preventing the rivet block 3 from being easily deformed due to its own length being too long. M≥5mm. This setting can ensure the minimum value of the single-side length of the rivet block 3, thereby ensuring the lower limit of the overall length of the rivet block 3, and further ensuring the area of ​​the rivet block 3. In this way, the welding area between the rivet block 3 and the battery pack tab can be guaranteed, which can increase the welding area between the rivet block 3 and the tab, and ensure the reliability and current capacity of the connection.

[0059] Riveted blocks 3 with different single-side lengths M were designed, and the states of the riveted blocks 3 were observed during production and assembly. The test results are shown in Table 3.

[0060] Table 3

[0061] M / mm result Example 1 5 OK Example 2 10 OK Example 3 50 OK Comparative Example 1 4 Insufficient welding area between the rivet block surface and the bar Comparative Example 2 55 The riveting block itself is easily deformed

[0062] It can be seen from Examples 1 to 3 in Table 3 that when the single-side length of the rivet block 3 satisfies 5mm≤M≤50mm, the length of the rivet block 3 itself is appropriate, the rivet block 3 is in good condition and does not deform during the production and assembly process, and the welding area between the rivet block 3 and the bar can also be guaranteed; it can be seen from Comparative Example 1 in Table 3 that when M is less than 5mm, the surface area of ​​the rivet block 3 is too small, resulting in insufficient welding area between it and the bar; it can be seen from Comparative Example 2 in Table 3 that when M is greater than 50mm, the rivet block 3 is easily deformed due to its own excessive length.

[0063] The cover body 1 is long and narrow, and its width is relatively narrow. For battery cells with large current flow capacity requirements, the current flow capacity of the battery cells cannot be increased by increasing the diameter of the column part 52. The size of the column part 52 can only be increased in the length direction of the cover body 1, thereby forming a long and narrow column part 52. When assembling the cover, the end of the column part 52 facing the rivet block 3 needs to be riveted to the rivet block 3. During the riveting process, the column part 52 is punched by a riveting punch to rivet and expand the material. The riveting punch applies pressure to the outside from the middle area of ​​the column part 52. If there are sharp corners on the side of the column part 52, it will cause uneven expansion at the corners of the column part 52. After riveting, the column part 52 cannot be effectively fitted with the rivet block 3. After laser welding the column part 52 and the rivet block 3, cold welding and unstable internal resistance are likely to occur. In order to solve this problem, Figure 7 and Figure 8 As shown, in some optional embodiments, the cross-section of the column portion 52 is in the shape of an athletic track or an ellipse, that is, the side wall of the column portion 52 in the length direction and the side wall in the width direction thereof are smoothly transitioned, so that the side wall of the column portion 52 can be prevented from having sharp corners, and the pole 5 can be ensured to expand uniformly at various circumferential positions during riveting, and each position of the column portion 52 can be effectively fitted with the riveting block 3. After the column portion 52 and the riveting block 3 are laser welded, the reliability of the welding between the two can be guaranteed, and the internal resistance of the battery and the stability of the battery operation can be guaranteed.

[0064] The columnar portion 52 in the shape of a track and field track means that the middle region of the cross section of the columnar portion 52 is rectangular, and the regions at both ends of the middle region are semicircular, and the diameter of the semicircle is equal to the width of the rectangular region.

[0065] Optionally, the column portion 52 is in the shape of an athletic track, and the support steps 521 on the column portion 52 facing the riveting block 3 and the column portion 52 facing the bottom plate 51 of the pole 5 are both in the shape of an athletic track. The support step 521 on the column portion 52 facing the riveting block 3 is located in the middle area of ​​the outer surface of the column portion 52 facing the bottom plate 51 of the pole 5, so as to form support steps 521 of the same width at both ends of the column portion 52 in the length direction, and support steps 521 of the same width are formed at both ends of the column portion 52 in the width direction.

[0066] In other embodiments, the shape of the column portion 52 can also be other shapes, for example, the middle area of ​​the cross section of the column portion 52 is rectangular, and the areas at both ends of the middle area are arc-shaped. In other embodiments, the cross section of the column portion 52 can also be rectangular.

[0067] like Figure 7 and Figure 8 As shown, the cross-section of the bottom plate 51 of the pole 5 is rectangular, and the cross-sectional area of ​​the bottom plate 51 is larger than that of the column portion 52. The cover plate also includes a seal 6, which is disposed between the cover plate body 1 and the pole 5. The side surface of the bottom plate 51 facing the outside of the cover plate abuts against the seal 6. The bottom plate 51 and the rivet block 3 clamp the first insulating member 2, the second insulating member 4 of the cover plate body 1, and the seal 6.

[0068] In some embodiments, a pre-riveted groove 522 is provided on the surface of the column portion 52 facing the outer side of the cover before riveting. The long side of the pre-riveted groove 522 extends in the same direction as the long side of the column portion 52. When riveting the terminal 5, the riveting punch presses downward on the pre-riveted groove 522 to apply force, facilitating the expansion of the column portion 52 and riveting it to the riveting block 3.

[0069] 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.

[0070] 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.

[0071] In a battery cell of this structure, a support step 521 is provided on the peripheral side wall of the column portion 52 of the pole 5 on the cover plate. The surface of the rivet block 3 facing the inner side of the cover plate abuts against the support step 521. When riveting the pole 5, the rivet block 3 is subjected to the downward force of the rivet punch. The support step 521 supports the rivet block 3, which to a certain extent alleviates the degree of collapse of the middle area of ​​the rivet block 3. The length of the solid part of the rivet block 3 on the side of the rivet hole is M, the lengths of the column part 52 located on the inner and outer sides of the support step 521 are L1 and L2 respectively, (L2-L1) / 2 is the average width of the support step 521 on one side of the length direction of the column part 52, M, L1 and L2 satisfy 1.5≤M / ((L2-L1) / 2)≤150, and the ratio of the length of the unilateral rivet block 3 to the average width of the support step 521 is controlled within an appropriate range through this formula, which can avoid the rivet block 3 being too long on one side or the support step 521 being too narrow, and can ensure the support effect of the support step 521 on the middle area of ​​the rivet block 3, thereby avoiding the rivet block 3 from sagging in the middle area and warping at both ends in the length direction when the rivet block 3 is riveted to the pole 5. Therefore, the flatness of the rivet block 3 can be effectively guaranteed, and the flatness of the rivet block 3 can be controlled within the required range, which can effectively ensure the sealing and safety performance of the battery cell.

[0072] 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 5 is provided on the positive cover plate, and a negative electrode column 5 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.

[0073] 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.

[0074] According to another aspect of an embodiment of the present invention, a battery pack is provided, comprising the battery cell of the above embodiment.

[0075] In a battery pack of this structure, a cover plate thereon is provided with a support step 521 on the peripheral side wall of the column portion 52 of the pole 5, and the dimensions M, L1 and L2 of the rivet block 3 and the support step 521 satisfy 1.5≤M / ((L2-L1) / 2)≤150. By using this formula, the ratio of the length of the single-sided rivet block 3 to the average width of the support step 521 is controlled within a suitable range, thereby ensuring the supporting effect of the support step 521 on the middle area of ​​the rivet block 3, thereby preventing the rivet block 3 from sagging in the middle area and warping at both ends in the length direction when riveted to the pole 5. Therefore, the flatness of the rivet block 3 can be effectively guaranteed, and the flatness of the rivet block 3 can be controlled within the required range, which can effectively ensure the sealing and safety performance of the battery cell, thereby ensuring the safety performance of the battery pack.

[0076] 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: Cover plate body; A first insulating member is provided on a surface of the cover body facing the outer side of the cover; a rivet block having a rivet hole and disposed on the first insulating member, wherein the rivet block and the cover body extend in the same direction and the length of the rivet block is greater than the width; Along the length direction of the rivet block, the length between one end of the rivet block and the corresponding inner side wall of the rivet hole is M; a second insulating member, provided on the other side surface of the cover body facing the inner side of the cover; A pole, comprising a base plate and a column portion provided on the base plate; the base plate is provided on the inner side of a surface of the second insulating member facing the inner side of the cover plate; the column portion extends in the same direction as the rivet block and its length is greater than its width, and a supporting step is provided on the peripheral side wall of the column portion; the column portion passes through the second insulating member, the cover plate body, the first insulating member and the rivet block, and a surface of the rivet block facing the inner side of the cover plate abuts on the supporting step; the length of the column portion located on the side of the support step facing the outer side of the cover plate is L1, and the length of the column portion located on the side of the support step facing the inner side of the cover plate is L2, 1.5≤M / ((L2-L1) / 2)≤150, and the units of M, L1 and L2 are mm.

2. The cover plate according to claim 1, wherein: The widths of the support steps on both sides of the column portion in the length direction are the same.

3. The cover plate according to claim 2, wherein: 0.2mm≤(L2-L1) / 2≤10mm.

4. The cover plate according to claim 3, wherein: Along the width direction of the cover plate, the width of the column portion located on the side of the support step facing the outer side of the cover plate is W1, and the width of the column portion located on the side of the support step facing the inner side of the cover plate is W2. The widths of the support steps on both sides of the width direction of the column portion are the same, 0.2mm≤(W2-W1) / 2≤10mm, and the units of W1 and W2 are mm.

5. The cover plate according to claim 4, characterized in that: (W2-W1) / 2≤(L2-L1) / 2.

6. The cover plate according to any one of claims 1 to 5, characterized in that: 5mm≤M≤50mm.

7. The cover plate according to any one of claims 1 to 5, characterized in that: The cross section of the column portion is in the shape of a track or an ellipse.

8. The cover plate according to any one of claims 1 to 5, characterized in that: Before riveting, a pre-rivet groove is provided on the surface of the column portion facing the outer side of the cover plate, and the long side of the pre-rivet groove extends in the same direction as the long side of the column portion.

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.

Images