Battery cover plate and battery

Abstract

The invention belongs to the technical field of batteries, and discloses a battery cover plate and a battery, the battery cover plate comprises a connecting sheet and a copper-aluminum composite pole, the connecting sheet comprises a connecting body and a plugging boss, the copper-aluminum composite pole comprises a first pole body and a second pole body, a copper-aluminum interface is formed between the first pole body and the second pole body, and the plugging boss is arranged on the connecting body. The first pole body is provided with a first limiting structure, the length size of the first pole body along the first direction is L, the length size of the first limiting structure along the first direction is L1, and (L-L1) / 2 is greater than or equal to 2mm. On one hand, the accuracy of the relative position of the connecting piece and the copper-aluminum composite pole column is ensured through the insertion of the insertion bulge and the first limiting structure during welding, and the damage to a copper-aluminum interface caused by dislocation is avoided, and on the other hand, the length size L and the length size L1 are limited; and enough structural strength between the first limiting structure and the copper-aluminum interface is ensured, so that relatively high connection precision and welding yield are achieved after welding.

Description

Technical Field

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

[0002] As an important part of lithium batteries, the structural design of the battery cover not only affects the basic performance of the battery, such as capacity and charge and discharge efficiency, but is also directly related to the safety and long-term reliability of the battery. The main structural components of the battery cover include conductive electrode columns, connecting plates, bare aluminum plates, insulating parts and explosion-proof valves. The pole ears of the pole group are fixed by laser welding with the pole base of the cover through the connecting plates to achieve electrical connection, thereby leading the internal current of the battery cell to the outside of the shell. The positive pole column connected to the positive pole ear is generally made of pure aluminum, and the negative pole column connected to the negative pole ear is generally made of pure copper. However, since the cost and weight of copper are greater than that of aluminum, the use of pure copper as the pole column not only increases the production cost, but also increases the overall weight of the lithium-ion battery, which does not conform to the principle of lightweight structural design.

[0003] Therefore, a copper-aluminum composite material is used to prepare a negative electrode column connected to the negative electrode ear. However, when welding the connecting piece and the copper-aluminum composite electrode, there is a problem of deviation in the welding position due to relative displacement between the connecting piece and the copper-aluminum composite electrode. As a result, after the connecting piece and the copper-aluminum composite electrode are welded, there is a problem of cracking due to the welding position being too close to the interface of the copper-aluminum composite electrode. The connection stability is poor, and the connection accuracy and product yield after welding are low. Summary of the invention

[0004] The object of the present invention is to provide a battery cover plate and a battery, which have good connection stability, high connection accuracy and high product yield after welding.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In one aspect, a battery cover is provided, the battery cover comprising:

[0007] A connecting piece, the connecting piece comprising a connecting body and a plug-in boss, wherein a side of the connecting body facing away from the plug-in boss is connected to the pole ear;

[0008] A copper-aluminum composite pole, the copper-aluminum composite pole comprising a first pole body and a second pole body, one of the first pole body or the second pole body is made of aluminum, the other of the first pole body or the second pole body is made of copper, a mounting through hole is provided on the second pole body, the first pole body is connected to the mounting through hole, and a copper-aluminum interface is formed between the first pole body and the second pole body, a first limiting structure is provided on the first pole body, and the plug-in boss is inserted into the first limiting structure;

[0009] The length of the first pole along the first direction is L, the length of the first limiting structure along the first direction is L1, and (L-L1) / 2≥2 mm is satisfied.

[0010] Optionally, the first limiting structure is a blind groove, and is provided on a side of the first pole body facing the connecting piece;

[0011] The depth dimension of the first limiting structure along the second direction is H1, the thickness dimension of the first pole body along the second direction is H, and 0.5 mm ≤ (H-H1) < H is satisfied.

[0012] Optionally, a second limiting structure is further provided on a side of the first pole body away from the connecting piece, and a depth dimension of the second limiting structure along the second direction is H2, and satisfies 0.1 mm<H2<(H-H1).

[0013] Optionally, one of the first limiting structure or the plug-in boss which is a blind groove is provided with a positioning column, and the other of the first limiting structure or the plug-in boss is provided with a positioning hole, and the positioning column is inserted into the positioning hole.

[0014] Optionally, a height dimension of the positioning column along the second direction is T, and satisfies T≥0.3 mm.

[0015] Optionally, when the first pole body is made of copper, the first pole body is welded to the plug-in boss or the connecting body;

[0016] Alternatively, when the first pole body is made of aluminum, the connecting body and the second pole body are welded.

[0017] Optionally, when the first limiting structure is a through hole and the first pole body is made of copper, the plug-in boss is welded to the first pole body and 0.2≤L1 / L≤0.8 is satisfied.

[0018] Optionally, when the first limiting structure is a through hole and the first pole body is made of aluminum, the connecting body and the second pole body are welded and 0.2≤L1 / L≤0.84 is satisfied.

[0019] Optionally, the second pole body includes an extension portion, a main body portion and a connecting portion, the mounting through hole is provided on the main body portion, and the connecting portion is used to connect the extension portion and the main body portion to form the second pole body in an X-shape.

[0020] On the other hand, a battery is provided, comprising a battery casing, a pole group and a battery cover as described in any one of the above items, wherein the battery cover and the battery casing together form a closed chamber for accommodating the pole group.

[0021] Beneficial effects of the present invention:

[0022] The present invention provides a battery cover plate, which is provided with a plug-in boss on a connecting piece and a first limiting structure on a first pole body of a copper-aluminum composite pole, so that during welding, the plug-in boss is plugged into the first limiting structure, thereby limiting the relative position between the copper-aluminum composite pole and the connecting piece, avoiding relative displacement between the copper-aluminum composite pole and the connecting piece during welding, thereby causing a deviation in the welding position, and further causing the high temperature generated during welding to have a thermal impact on the copper-aluminum interface of the copper-aluminum composite pole, so that cracks are generated at the copper-aluminum interface, and fracture occurs. , and by limiting the relationship between the length dimension L of the first pole body along the first direction and the length dimension L1 of the first limiting structure along the first direction, the two satisfy (L-L1) / 2≥2mm, thereby ensuring that the first limiting structure is sufficiently far away from the copper-aluminum interface, ensuring the structural strength between the first limiting structure and the copper-aluminum interface, avoiding deformation of the first pole body during welding and damaging the copper-aluminum interface, so that when the copper-aluminum composite pole of the battery cover plate is welded to the connecting piece, it has better connection stability, higher connection accuracy and higher yield rate after welding.

[0023] The present invention also provides a battery, which, by applying the above-mentioned battery cover, has good connection stability and connection accuracy, thereby improving product quality and extending service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural cross-sectional view when the first limiting structure on the copper-aluminum composite pole provided by the present invention is a blind groove;

[0025] Figure 2 It is a structural cross-sectional view when the first limiting structure on the copper-aluminum composite pole provided by the present invention is a through hole;

[0026] Figure 3 It is a structural cross-sectional view of the first pole body and the plug-in boss of the connecting piece after welding when the first limiting structure on the copper-aluminum composite pole in the battery cover provided by the present invention is a blind groove;

[0027] Figure 4 It is a structural cross-sectional view of the first pole body and the connecting body of the connecting piece after welding when the first limiting structure on the copper-aluminum composite pole in the battery cover provided by the present invention is a blind groove;

[0028] Figure 5 It is a structural cross-sectional view of the second pole body of the copper-aluminum composite pole in the battery cover provided by the present invention and the connecting body of the connecting piece after welding;

[0029] Figure 6It is a structural cross-sectional view of the first pole body and the plug-in boss of the connecting piece after welding when the first limiting structure on the copper-aluminum composite pole in the battery cover provided by the present invention is a through hole;

[0030] Figure 7 It is a structural cross-sectional view of the second pole body and the connecting body of the connecting piece after welding when the first limiting structure on the copper-aluminum composite pole in the battery cover provided by the present invention is a through hole.

[0031] In the figure:

[0032] 1. Connecting piece; 11. Connecting body; 12. Inserting boss;

[0033] 2. Copper-aluminum composite pole; 21. First pole body; 211. First limiting structure; 212. Second limiting structure; 22. Second pole body; 221. Extension part; 222. Main body; 223. Connecting part; 23. Copper-aluminum interface; 24. Positioning column. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0035] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0037] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0038] When welding the copper-aluminum composite pole and the connecting piece, there is a relative displacement between the connecting piece and the copper-aluminum composite pole, which causes a deviation in the welding position. As a result, after the connecting piece and the copper-aluminum composite pole are welded, there is a problem of cracking due to the welding position being too close to the interface of the copper-aluminum composite pole. The connection stability is poor, and the connection accuracy and product yield after welding are low.

[0039] Therefore, in order to improve the stability of the connection, increase the connection accuracy and the product yield after welding, this embodiment provides a battery cover.

[0040] like Figures 1 to 7 As shown, the battery cover includes a connecting piece 1 and a copper-aluminum composite pole 2, the connecting piece 1 includes a connecting body 11 and a plug-in boss 12, the connecting body 11 is connected to the pole ear on one side away from the plug-in boss 12, the copper-aluminum composite pole 2 includes a first pole body 21 and a second pole body 22, one of the first pole body 21 or the second pole body 22 is made of aluminum, and the other of the first pole body 21 or the second pole body 22 is made of copper, and a mounting through hole is provided on the second pole body 22, the first pole body 21 is connected to the mounting through hole, and a copper-aluminum interface 23 is formed between the first pole body 21 and the second pole body 22, a first limiting structure 211 is provided on the first pole body 21, the plug-in boss 12 is inserted in the first limiting structure 211, the length dimension of the first pole body 21 along the first direction is L, the length dimension of the first limiting structure 211 along the first direction is L1, and (L-L1) / 2≥2mm is satisfied.

[0041] The battery cover plate is provided with a plug-in boss 12 on the connecting sheet 1, and a first limiting structure 211 is provided on the first pole body 21 of the copper-aluminum composite pole 2, so that during welding, the plug-in boss is plugged into the first limiting structure 211, thereby limiting the relative position between the copper-aluminum composite pole 2 and the connecting sheet 1, avoiding relative displacement between the copper-aluminum composite pole 2 and the connecting sheet 1 during welding, thereby causing deviation in the welding position, and further causing the high temperature generated during welding to have a thermal impact on the copper-aluminum interface 23 of the copper-aluminum composite pole 2, so that cracks are generated at the copper-aluminum interface 23, and fracture occurs, and by The relationship between the length dimension L of the first pole body 21 along the first direction and the length dimension L1 of the first limiting structure 211 along the first direction is limited so that the two satisfy (L-L1) / 2≥2mm, thereby ensuring that the first limiting structure 211 is sufficiently far away from the copper-aluminum interface 23, ensuring the structural strength between the first limiting structure 211 and the copper-aluminum interface 23, avoiding deformation of the first pole body 21 during welding and damaging the copper-aluminum interface 23, so that when the copper-aluminum composite pole 2 of the battery cover plate is welded to the connecting piece 1, it has better connection stability, higher connection accuracy and higher yield rate after welding.

[0042] Among them, the type of the battery cover can be freely selected, such as a welded cover, a riveted cover, etc. In addition to the connecting piece 1 and the copper-aluminum composite pole 2, the battery cover also includes a bare aluminum plate, a connecting piece, an external insulating piece, an internal insulating piece, etc. The connecting piece has different ways of connecting the copper-aluminum composite pole 2 to the bare aluminum plate according to the type of the cover. When a welded cover is used, the connecting piece is a welding block, and the connection between the copper-aluminum composite pole 2 and the bare aluminum plate is achieved by welding. When a riveted cover is used, the connecting piece is a riveted block, and the connection between the copper-aluminum composite pole 2 and the bare aluminum plate is achieved by riveting. The external insulating piece and the internal insulating piece are respectively arranged on both sides of the bare aluminum plate to achieve insulation protection and avoid short circuit.

[0043] Among them, in order to determine the relationship between the length dimension L of the first pole body 21 along the first direction and the length dimension L1 of the first limiting structure 211 along the first direction, for the influence after welding of the copper-aluminum composite pole 2 and the connecting piece 1, as shown in Table 1, four groups of embodiments and four groups of comparative examples are provided for verification, and it is observed whether cracks appear at the copper-aluminum interface 23 after welding, wherein the first pole body 21 is set to copper and the second pole body 22 is set to aluminum.

[0044] Table 1

[0045]

[0046] It can be seen from Table 1 that in Examples 1 to 4, the values ​​of the relationship (L-L1) / 2 are not less than 2 mm. At this time, the test result is that no cracks are found at the copper-aluminum interface 23. By comparing and observing Comparative Examples 1 to 4, the values ​​of the relationship (L-L1) / 2 are all less than 2 mm. At this time, the test result is that cracks occur at the copper-aluminum interface 23. It can be seen that when the values ​​of the relationship (L-L1) / 2 are all less than 2 mm, at this time, the copper-aluminum interface 23 is too close to the first limiting structure 211, resulting in poor structural strength. After the copper-aluminum composite pole 2 is welded to the connecting piece 1, the deformation of the first pole body 21 has a greater impact on the copper-aluminum interface 23, thereby causing cracks to appear at the copper-aluminum interface 23 after welding.

[0047] Alternatively, if Figure 1 As shown, the first limiting structure 211 is a blind groove and is provided on the side of the first pole body 21 facing the connecting piece 1. The depth dimension of the first limiting structure 211 along the second direction is H1, and the thickness dimension of the first pole body 21 along the second direction is H, and 0.5mm≤(H-H1)<H is satisfied.

[0048] It can be understood that when the first limiting structure 211 is a blind groove, when the plug-in boss 12 is inserted into the first limiting structure 211, the surface of the plug-in boss 12 facing away from the connecting body 11 abuts against the bottom of the first limiting structure 211 whose structure is a blind groove. At this time, the relationship between the depth dimension H1 of the first limiting structure 211 along the second direction and the thickness dimension H of the first pole body 21 along the second direction is limited, so as to avoid, on the one hand, the thickness of the remaining material after the first limiting structure 211 is opened on the first pole body 21, which is too thin, resulting in poor structural strength of the first pole body 21, easy deformation during welding, and affecting the copper-aluminum interface 23; on the other hand, it is avoided that after the first limiting structure 211 is opened on the first pole body 21, the thickness of the remaining material is too large, resulting in the groove depth of the first limiting structure 211 being too shallow, and the depth of the plug-in boss 12 and the first limiting structure 211 being inserted into each other is too short, and the copper-aluminum composite pole 2 and the connecting piece 1 cannot be effectively limited and fixed.

[0049] Among them, in order to determine the relationship between the depth dimension H1 of the first limiting structure 211 having a blind groove structure along the second direction and the thickness dimension H of the first pole body 21 along the second direction, and the influence on the welding of the copper-aluminum composite pole 2 and the connecting piece 1, as shown in Table 2, four groups of embodiments and four groups of comparative examples are provided for verification, and whether cracks appear at the copper-aluminum interface 23 after welding, wherein the first pole body 21 is set to copper and the second pole body 22 is set to aluminum.

[0050] Table 2

[0051]

[0052] It can be seen from Table 2 that in Examples 5 to 8, the values ​​of the relationship (H-H1) are all greater than 0.5 mm. At this time, the test results show that the first pole body 21 is deformed less, and no cracks are found at the copper-aluminum interface 23. By comparing and observing Comparative Examples 5 to 8, the values ​​of the relationship (H-H1) are all less than 0.5 mm. At this time, the test results show that the first pole body 21 is deformed more, and cracks are found at the copper-aluminum interface 23. It can be seen that when the values ​​of the relationship (H-H1) are all greater than 0.5 mm, the material remaining after the first limiting structure 211 is opened in the first pole body 21 has sufficient thickness, thereby ensuring the structural strength of the first pole body 21 itself, avoiding deformation of the first pole body 21 during welding, thereby causing cracks at the copper-aluminum interface 23.

[0053] Specifically, when the first pole body 21 is made of copper, the first pole body 21 is welded to the plug-in boss 12 or the connecting body 11;

[0054] Alternatively, when the first pole body 21 is made of aluminum, the connecting body 11 and the second pole body 22 are welded.

[0055] In this embodiment, since the first limiting structure 211 is a blind groove, when the first pole column 21 is made of copper, there are two different ways to weld the connecting piece 1 to the first pole column 21. The first way is as follows: Figure 3 As shown, the penetration welding method is adopted, and the copper-aluminum composite pole 2 is welded in the direction of the connecting piece 1, that is, the plug-in boss 12 is welded and fixed to the first pole body 21. The second method is as follows Figure 4 As shown, the penetration welding method is adopted, and the connection sheet 1 is welded toward the copper-aluminum composite pole 2, that is, the connection body 11 and the first pole body 21 are welded. At this time, the plug-in boss 12 and the first limiting structure 211 only have the function of limiting. Figure 5 As shown, when the first pole body 21 is made of aluminum, penetration welding is used to weld the connection body 11 to the second pole body 22. In addition, as the first limiting structure 211 of the blind groove structure, its shape can be freely set according to demand, such as rectangular, circular, etc., and the shape of the plug-in boss 12 is adapted to the shape of the first limiting structure 211, so that the two can be plugged in.

[0056] Furthermore, if Figure 1 As shown, a second limiting structure 212 is further provided on the side of the first pole column 21 away from the connecting piece 1, and the depth dimension of the second limiting structure 212 along the second direction is H2, and 0.1mm<H2<(H-H1). By providing the second limiting structure 212 on the side of the first pole column 21 away from the connecting piece 1, as shown Figure 3As shown, on the one hand, when the first pole body 21 is made of copper and penetration welding is adopted from the copper-aluminum composite pole 2 to the direction of the connecting piece 1, the thickness of the first pole body 21 is further reduced by providing a second limiting structure 212, thereby facilitating penetration welding. On the other hand, when the first pole body 21 is made of aluminum, the second limiting structure 212 can also be used as a positioning structure when the copper-aluminum composite pole 2 is welded to the busbar, and by limiting the depth dimension H2 of the second limiting structure 212 along the second direction, when the first pole body 21 is copper, the depth of the second limiting structure 212 is prevented from being too shallow, thereby increasing the difficulty of penetration welding. When the first pole body 21 is aluminum, the depth of the busbar and the copper-aluminum composite pole 2 is prevented from being too shallow, thereby preventing the two from being effectively limited.

[0057] Alternatively, if Figure 1 As shown, one of the first limiting structure 211 or the plug-in boss 12, which is a blind groove, is provided with a positioning column 24, and the other of the first limiting structure 211 or the plug-in boss 12 is provided with a positioning hole, and the positioning column 24 is inserted into the positioning hole. By providing the positioning column 24 in one of the first limiting structure 211 or the plug-in boss 12, which is a blind groove, and providing the positioning hole in the other of the first limiting structure 211 or the plug-in boss 12, a double positioning effect is achieved, thereby increasing the accuracy of positioning and ensuring the accuracy of the position during welding. In this embodiment, the positioning column 24 is arranged in the first limiting structure 211, and the positioning hole is arranged in the plug-in boss 12.

[0058] Furthermore, if Figure 1 As shown, the height dimension of the positioning column 24 along the second direction is T, and satisfies T≥0.3mm. By limiting the height dimension T of the positioning column 24 along the second direction, it is avoided that the height of the positioning column 24 is too small, resulting in weak structural strength and failure to effectively limit the copper-aluminum composite pole 2 and the connecting piece 1.

[0059] Alternatively, if Figure 2 As shown, when the first limiting structure 211 is a through hole and the first pole body 21 is made of copper, the plug-in boss 12 is welded to the first pole body 21 and 0.2≤L1 / L≤0.8 is satisfied.

[0060] It is understandable that if Figure 6As shown, when the first limiting structure 211 is a through hole, the plug-in boss 12 is inserted into the first limiting structure 211, and the surface of the plug-in boss 12 facing away from the connecting body 11 is flush with the surface of the first pole column 21 facing away from the connecting plate 1. Since the first pole column 21 is made of copper, the connecting plate 1 used as the connecting ear is required to be welded with the plug-in boss 12 of the connecting plate 1 and the first pole column 21. By limiting the relationship between the length dimension L of the first pole column 21 along the first direction and the length dimension L1 of the first limiting structure 211 along the first direction, on the one hand, it is avoided that the length dimension L1 is too small, resulting in too small spacing between welds during welding, resulting in mutual influence between welds, and on the other hand, it is avoided that the length dimension L1 is too large, resulting in too close to the copper-aluminum interface 23, resulting in thermal influence on the copper-aluminum interface 23.

[0061] In this embodiment, the shape of the first limiting structure 211 as a through-hole structure can be freely set according to needs, such as rectangular, circular, etc., and the shape of the plug-in boss 12 is adapted to the shape of the first limiting structure 211 so that the two can be plugged together.

[0062] Among them, in order to verify the influence of the ratio between the length dimension L of the first pole body 21 along the first direction and the length dimension L1 of the first limiting structure 211 along the first direction on the welding between the plug-in boss 12 and the first pole body 21 when the first pole body 21 is made of copper and the first limiting structure 211 is a through hole, as shown in Table 3, four groups of embodiments and four groups of comparative examples are provided for verification.

[0063] Table 3

[0064]

[0065] It can be seen from Table 3 that in Examples 9 to 12, the values ​​of the relationship (L1 / L) all meet the range requirement of 0.2≤L1 / L≤0.8. At this time, the test result is that the welding of the plug-in boss 12 and the first pole body 21 is normal, and no cracks are found at the copper-aluminum interface 23. By comparing and observing Comparative Examples 9 and 10, the values ​​of the relationship (L1 / L) are all less than 0.2 mm. At this time, the test result is that the welding of the plug-in boss 12 and the first pole body 21 is abnormal. At this time, it is proved that due to the small length dimension L1, the spacing between the welds is too small during welding, resulting in mutual influence between the welds, thereby causing abnormal welding. By comparing and observing Comparative Examples 11 and 12, the values ​​of the relationship (L1 / L) are all greater than 0.8. At this time, the test result is that cracks are found at the copper-aluminum interface 23. At this time, it is proved that due to the large length dimension L1, it is too close to the copper-aluminum interface 23, resulting in thermal influence at the copper-aluminum interface 23, causing cracks at the copper-aluminum interface 23.

[0066] Alternatively, if Figure 2As shown, when the first limiting structure 211 is a through hole and the first pole body 21 is made of aluminum, the connecting body 11 and the second pole body 22 are welded and 0.2≤L1 / L≤0.84 is satisfied.

[0067] It can be understood that when the first limiting structure 211 is a through hole, the plug-in boss 12 is inserted into the first limiting structure 211, and the surface of the plug-in boss 12 facing away from the connecting body 11 is flush with the surface of the first pole column 21 facing away from the connecting piece 1. However, since the first pole column 21 is made of aluminum, the second pole column 22 is made of copper at this time. Therefore, the connecting piece 1 used as the connecting ear is Figure 7 As shown, the connecting body 11 of the connecting piece 1 needs to be welded to the second pole body 22. At this time, the relationship between the length dimension L of the first pole body 21 along the first direction and the length dimension L1 of the first limiting structure 211 along the first direction is limited. On the one hand, the length dimension L1 is prevented from being too small, and the opening of the first limiting structure 211 of the through hole is too small, resulting in poor structural strength after the plug-in boss 12 and the first limiting structure 211 are plugged in, and it is impossible to effectively resist the movement trend of the connecting piece 1 and the copper-aluminum composite pole 2 during welding, resulting in misalignment between the two. On the other hand, it is necessary to ensure that there is sufficient structural strength between the first limiting structure 211 and the copper-aluminum interface 23, that is, under the premise of satisfying (L-L1) / 2≥2mm, if the opening of the first limiting structure 211 is too large, the overall structural size of the copper-aluminum composite pole 2 is increased, there is size redundancy, and material waste.

[0068] In this embodiment, the shape of the first limiting structure 211 as a through-hole structure can be freely set according to needs, such as rectangular, circular, etc., and the shape of the plug-in boss 12 is adapted to the shape of the first limiting structure 211 so that the two can be plugged together.

[0069] Among them, in order to verify the influence of the ratio between the length dimension L of the first pole body 21 along the first direction and the length dimension L1 of the first limiting structure 211 along the first direction on the welding between the connecting body 11 and the first pole body 21 when the first pole body 21 is made of aluminum and the first limiting structure 211 is a through hole, as shown in Table 4, four groups of embodiments and four groups of comparative examples are provided for verification.

[0070] Table 4

[0071]

[0072] As can be seen from Table 4, in Examples 13 to 16, the values ​​of the relationship (L1 / L) all meet the range requirement of 0.2≤L1 / L≤0.84. At this time, the test result shows that the copper-aluminum composite pole 2 and the connecting piece 1 do not shift during welding. By comparing Comparative Examples 13 and 14, the values ​​of the relationship (L1 / L) are all less than 0.2 mm. At this time, the test result shows that the copper-aluminum composite pole 2 and the connecting piece 1 shift during welding. At this time, it is proved that the length dimension L1 is too small, which is the first limit of the through hole. The opening of the structure 211 is too small, resulting in poor structural strength after the plug-in boss 12 is plugged into the first limiting structure 211, and cannot effectively resist the movement trend of the connecting piece 1 and the copper-aluminum composite pole 2 during welding, resulting in misalignment between the two. By comparing comparative examples 15 and 16, the values ​​of the relationship (L1 / L) are both greater than 0.84. At this time, although the copper-aluminum composite pole 2 and the connecting piece 1 do not move during welding, the manufacturing cost is significantly increased compared with Examples 13 to 16.

[0073] Alternatively, if Figure 1 As shown, the second pole body 22 includes an extension portion 221, a main body portion 222 and a connecting portion 223. The mounting through hole is provided on the main body portion 222. The connecting portion 223 is used to connect the extension portion 221 and the main body portion 222 to form an "X"-shaped second pole body 22. By providing the main body portion 222 on the second pole body 22, on the one hand, it is convenient to shorten the distance with the busbar and connect with the busbar, and on the other hand, the "X"-shaped second pole body 22 has a groove structure for accommodating the connecting piece 1, so that there is a spatial overlap between the second pole body 22 and the connecting piece 1, saving space.

[0074] In this embodiment, a battery is also provided, the battery comprising a battery housing, an electrode group and the above-mentioned battery cover, the battery cover and the battery housing together enclose a closed chamber for accommodating the electrode group. By applying the above-mentioned battery cover, the battery has better connection stability and connection accuracy, thereby improving product quality and extending service life.

[0075] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A battery cover, characterized in that: The battery cover comprises: A connecting piece, the connecting piece comprising a connecting body and a plug-in boss, wherein a side of the connecting body facing away from the plug-in boss is connected to the pole ear; A copper-aluminum composite pole, the copper-aluminum composite pole comprising a first pole body and a second pole body, one of the first pole body or the second pole body is made of aluminum, the other of the first pole body or the second pole body is made of copper, a mounting through hole is provided on the second pole body, the first pole body is connected to the mounting through hole, and a copper-aluminum interface is formed between the first pole body and the second pole body, a first limiting structure is provided on the first pole body, and the plug-in boss is inserted into the first limiting structure; The length of the first pole along the first direction is L, the length of the first limiting structure along the first direction is L1, and (L-L1) / 2≥2 mm is satisfied.

2. The battery cover according to claim 1, characterized in that: The first limiting structure is a blind groove and is arranged on a side of the first pole body facing the connecting piece; The depth dimension of the first limiting structure along the second direction is H1, the thickness dimension of the first pole body along the second direction is H, and 0.5 mm ≤ (H-H1) < H is satisfied.

3. The battery cover according to claim 2, characterized in that: A second limiting structure is further provided on a side of the first pole body away from the connecting piece. The depth dimension of the second limiting structure along the second direction is H2, and satisfies 0.1 mm<H2<(H-H1).

4. The battery cover according to claim 2, characterized in that: One of the first limiting structure or the plug-in boss which is a blind groove is provided with a positioning column, and the other of the first limiting structure or the plug-in boss is provided with a positioning hole, and the positioning column is inserted in the positioning hole.

5. The battery cover according to claim 4, characterized in that: The height dimension of the positioning column along the second direction is T, and satisfies T≥0.3 mm.

6. The battery cover according to claim 2, characterized in that: When the first pole body is made of copper, the first pole body is welded to the plug-in boss or the connecting body; Alternatively, when the first pole body is made of aluminum, the connecting body and the second pole body are welded.

7. The battery cover according to claim 1, characterized in that: When the first limiting structure is a through hole and the first pole body is made of copper, the plug-in boss is welded to the first pole body and 0.2≤L1 / L≤0.8 is satisfied.

8. The battery cover according to claim 1, characterized in that: When the first limiting structure is a through hole and the first pole body is made of aluminum, the connecting body and the second pole body are welded and 0.2≤L1 / L≤0.84 is satisfied.

9. The battery cover according to claim 1, characterized in that: The second pole body comprises an extension part, a main body part and a connecting part. The mounting through hole is provided on the main body part. The connecting part is used to connect the extension part and the main body part to form the second pole body in an X-shape.

10. A battery, characterized in that The battery comprises a battery casing, a pole group and a battery cover as claimed in any one of claims 1 to 9, wherein the battery cover and the battery casing together form a closed chamber for accommodating the pole group.

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