Battery cell cover plate assembly, battery cell and battery pack

Abstract

The utility model relates to the technical field of batteries, and discloses a battery cell cover plate assembly, a battery cell and a battery pack. The battery cell cover plate assembly comprises a cover plate, a pole and a connecting sheet, the cover plate is provided with a mounting hole, the pole is arranged in the mounting hole of the cover plate, the pole comprises a pole body, the pole body is provided with a pole groove, and the bottom wall of the pole groove of the pole is provided with a first through hole; the connecting piece is arranged on the inner side of the pole column, the connecting piece comprises a pole column connecting part, a connecting boss arranged on the pole column connecting part in a protruding mode and a pole group connecting part connected to one side of the pole column connecting part, and the top wall of the connecting boss corresponds to the bottom wall of the pole column groove and is welded to the bottom wall of the pole column groove; a second through hole is formed in the connecting boss of the connecting piece, and the second through hole and the first through hole are correspondingly matched to form a liquid injection hole. Instantaneous impact force cannot be generated due to riveting, the axial occupied space is reduced, the liquid injection holes are formed in the pole columns and the connecting pieces, the assembling procedures are reduced, and the production efficiency can be improved.

Description

Technical Field

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

[0002] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in the field of electric vehicles.

[0003] The electrode structure of a battery is generally that a cover plate and a pole post are riveted and connected, and then welded to a connecting piece. At the same time, a liquid injection hole is formed in the cover plate.

[0004] This traditional riveting scheme has a complex structure and many assembly processes, resulting in low production efficiency of the cell. Summary of the Utility Model

[0005] In view of this, the utility model provides a cell cover plate assembly, a cell and a battery pack to solve the problems of complex structure, many assembly processes and low production efficiency of the cell existing in the traditional riveting scheme.

[0006] In a first aspect, the utility model provides a cell cover plate assembly, including a cover plate, a pole post and a connecting piece. The cover plate is provided with an installation hole, the pole post is arranged in the installation hole of the cover plate, the pole post includes a pole post body, the pole post body is provided with a pole post groove, the pole post includes a positive pole post and / or a negative pole post, and a first through hole is arranged on the bottom wall of the pole post groove of one of the pole posts; the connecting piece is arranged inside the pole post, the connecting piece includes a pole post connecting portion, a connecting boss protruding from the pole post connecting portion and a pole group connecting portion connected to one side of the pole post connecting portion, the top wall of the connecting boss corresponds to the bottom wall of the pole post groove and is welded; a second through hole is arranged on the connecting boss of one of the connecting pieces, and the second through hole and the first through hole cooperate correspondingly to form a liquid injection hole.

[0007] Beneficial effects: In the cell cover plate assembly provided by the utility model, the pole post is provided with a pole post groove, the connecting piece is provided with a connecting boss, the pole post groove and the connecting boss are abutted and welded through penetration. Compared with the traditional technical scheme of using a riveting block for riveting, the utility model provides a new structural combination method, reduces the riveting parts, and only needs to weld the bottom wall of the pole post groove of the pole post and the top wall of the connecting boss, improving the assembly efficiency and performance; the utility model does not require riveting, and when an explosion-proof valve is arranged on the cover plate, the stability of the explosion-proof valve will not be affected by the instantaneous impact force generated by riveting, improving the yield. At the same time, due to the cancellation of the riveting block, the axial occupied space is reduced and the space utilization rate is improved. Since a first through hole is arranged in the pole post groove of one of the pole posts and a second through hole is arranged on the connecting boss of one of the connecting pieces, the first through hole and the second through hole form a liquid injection hole, and liquid can be injected from the liquid injection hole, reducing the assembly process and being beneficial to improving the production efficiency.

[0008] In an alternative embodiment, the thickness of the bottom wall of the pole post groove is T1, the outer surface of the connecting boss is higher than the outer surface of the pole post connecting portion, the thickness of the top wall of the connecting boss is T2, 0.8 mm ≤ T2 ≤ 1.8 mm, T2 ≤ T1, and T1 + T2 ≥ 2.8 mm.

[0009] In an alternative embodiment, the thickness of the pole post body is T, T ≥ 2 mm; the depth of the pole post groove is D, 0.2T ≤ D ≤ 2T.

[0010] In an alternative embodiment, the distance between the outer surface of the pole post body and the inner surface of the pole post connecting portion is H, 4.5 mm ≤ H ≤ 5.2 mm.

[0011] In an alternative embodiment, the thickness of the pole post connecting portion is T3, the thickness of the pole group connecting portion is T4, T2 ≥ T3 ≥ T4, the pole group connecting portion is recessed in the inner surface of the pole post connecting portion, and 0.2 mm ≤ T4 ≤ 2 mm.

[0012] In an alternative embodiment, the inner diameter of the second through hole is greater than the inner diameter of the first through hole.

[0013] In an alternative embodiment, the pole post groove includes a first bottom and a second bottom in a stepped shape, the first bottom is recessed in the second bottom; the cell cover plate assembly further includes a sealant nail and a welding ring. The sealant nail includes a head and a rod portion, the head is disposed on the first bottom, the rod portion is disposed in the liquid injection hole to seal the liquid injection hole; the welding ring is disposed on the second bottom and is located outside the sealant nail, and the welding ring is welded to the pole post body.

[0014] In an alternative embodiment, the pole post body of the pole post is disposed on the outer end surface of the mounting hole, a combined outer columnar surface is formed between the pole post body and the pole post connecting portion, and the combined outer columnar surface is disposed in the mounting hole; the cell cover plate assembly further includes an upper plastic, a sealing ring and a lower plastic sleeved on the combined outer columnar surface. The upper plastic is located on the outer end surface of the mounting hole to insulatively connect the pole post and the cover plate; the sealing ring is disposed between the mounting hole and the combined outer columnar surface to sealingly connect the pole post and the cover plate; the lower plastic is located on the inner end surface of the mounting hole to insulatively connect the connecting piece and the cover plate.

[0015] In a second aspect, the present invention further provides a cell, including a housing, a pole group, and the cell cover plate assembly according to any one of the above technical solutions. The housing is provided with an open end; the pole group is disposed in the housing, and the pole group is provided with pole tabs; the cell cover plate assembly is disposed at the open end of the housing to encapsulate the pole group in the housing, and the connecting piece of the cell cover plate assembly is welded to the pole group.

[0016] Advantageous effects: Since the cell includes the cell cover plate assembly, it has the same effects as the cell cover plate assembly, which will not be elaborated herein.

[0017] In a third aspect, the present utility model further provides a battery pack, which includes the battery cells in the above-mentioned technical solutions.

[0018] Beneficial effects: Since the battery pack includes the battery cells, it has the same effects as the battery cells, which will not be elaborated here. Description of the Drawings

[0019] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0020] Figure 1 It is a schematic structural diagram of a pole column in an embodiment of the present utility model;

[0021] Figure 2 It is Figure 1 the top view of the pole column shown;

[0022] Figure 3 It is a cross-sectional view along Figure 2 A-A in ;

[0023] Figure 4 It is a schematic structural diagram of a connecting piece in an embodiment of the present utility model;

[0024] Figure 5 It is Figure 4 the top view of the connecting piece shown;

[0025] Figure 6 It is a cross-sectional view along Figure 5 B-B in ;

[0026] Figure 7 It is Figure 1 the structural schematic diagram after the pole column shown is connected to Figure 4 the connecting piece shown;

[0027] Figure 8 It is Figure 7 the top view of ;

[0028] Figure 9 It is a cross-sectional view along Figure 8 C-C in ;

[0029] Figure 10 It is Figure 4 the structural schematic diagram after the connecting piece shown is welded to the pole group;

[0030] Figure 11 It is Figure 10 the top view of ;

[0031] Figure 12 For along Figure 11 Sectional view at DD in the middle;

[0032] Figure 13 for Figure 12 A magnified view of the local structure in ;

[0033] Figure 14 This is a schematic diagram of the structure of a battery cell according to an embodiment of the utility model;

[0034] Figure 15 for Figure 14 A top view of the battery cell shown;

[0035] Figure 16 For along Figure 15 Sectional view at EE;

[0036] Figure 17 for Figure 16 A magnified view of the local structure.

[0037] Description of reference numerals:

[0038] 1. Cover plate; 2. Pole; 21. Pole body; 22. Pole groove; 221. First groove bottom; 222. Second groove bottom; 23. First through hole; 3. Connecting piece; 31. Pole connecting part; 32. Connecting boss; 33. Pole group connecting part; 34. Second through hole; 4. Upper plastic; 5. Sealing ring; 6. Lower plastic; 7. Shell; 8. Pole group; 81. Pole ear; 9. Combined outer cylindrical surface; 10. Sealing nail; 20. Welding ring. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0040] The structural parts of lithium-ion batteries are also an important part of lithium-ion power batteries. They not only provide protection for lithium-ion batteries in terms of safety and reliability, but also take into account the connection between the internal chemical system of lithium-ion batteries and external modules and even the Pack. Since there are various connection relationships inside the structural parts and the requirements of sealing performance and current flow performance need to be taken into account at the same time, the design of the structural parts is particularly important.

[0041] Combine the following Figures 1 to 17 , describing an embodiment of the utility model.

[0042] According to an embodiment of the present utility model, in a first aspect, a cell cover plate assembly is provided, which includes a cover plate 1, a pole column 2, and a connecting piece 3. The cover plate 1 is provided with a mounting hole, the pole column 2 is disposed in the mounting hole of the cover plate 1. The pole column 2 includes a pole column body 21, and the pole column body 21 is provided with a pole column groove 22. The pole column 2 includes a positive pole column and / or a negative pole column. A first through hole 23 is provided on the bottom wall of the pole column groove 22 of one of the pole columns 2; the connecting piece 3 is disposed inside the pole column 2. The connecting piece 3 includes a pole column connecting portion 31, a connecting boss 32 protruding from the pole column connecting portion 31, and a pole group connecting portion 33 connected to one side of the pole column connecting portion 31. The top wall of the connecting boss 32 and the bottom wall of the pole column groove 22 are corresponding and welded; a second through hole 34 is provided on the connecting boss 32 of one of the connecting pieces 3, and the second through hole 34 and the first through hole 23 are correspondingly matched to form a liquid injection hole.

[0043] In the cell cover plate assembly provided by the embodiment of the present utility model, the pole column 2 is provided with the pole column groove 22, the connecting piece 3 is provided with the connecting boss 32, the pole column groove 22 and the connecting boss 32 are abutted and welded through penetration. Compared with the traditional technical solution of riveting with a riveting block, the present utility model provides a new structural combination method, reduces the riveting parts, and only needs to weld the bottom wall of the pole column groove 22 of the pole column 2 and the top wall of the connecting boss 32, improving the assembly efficiency and performance; the present utility model does not require riveting. When an explosion-proof valve is provided on the cover plate 1, the stability of the explosion-proof valve will not be affected by the instantaneous impact force generated by riveting, improving the production yield. At the same time, since the riveting block is cancelled, the axial occupied space is reduced, and the space utilization rate is improved. Since the first through hole 23 is provided in the pole column groove 22 of one of the pole columns 2, and the second through hole 34 is provided on the connecting boss 32 of one of the connecting pieces 3, the first through hole 23 and the second through hole 34 form a liquid injection hole, and liquid can be injected from the liquid injection hole, reducing the assembly process and being beneficial to improving the production efficiency.

[0044] Specifically, in this embodiment, the number of the connecting pieces 3 is correspondingly set to the number of the pole columns 2. One pole column 2 is connected to one connecting piece 3, and the pole column body 21 is used for welding with a bus bar to achieve electrical connection.

[0045] In some embodiments, the thickness of the bottom wall of the pole column groove 22 is T1, the outer surface of the connecting boss 32 is higher than the outer surface of the pole column connecting portion 31, the thickness of the top wall of the connecting boss 32 is T2, 0.8 mm ≤ T2 ≤ 1.8 mm, T2 ≤ T1, and T1 + T2 ≥ 2.8 mm.

[0046] It should be noted that, in this article, the inner surface of a structural member refers to that, in the state of a complete cell, the surface or end face facing the pole group 8 is the inner surface or inner end face, and the surface or end face away from the pole group 8 is the outer surface or outer end face.

[0047] Specifically, if the thickness T2 of the top wall of the connecting boss 32 is greater than 1.8 mm, it will result in excessive welding power, and defects such as explosion points and pores are likely to occur. If the thickness T2 of the top wall of the connecting boss 32 is less than 0.8 mm, it will lead to insufficient strength of the connecting boss 32, and thermal deformation is likely to occur during welding, affecting the welding reliability. Therefore, controlling the thickness T2 of the top wall of the connecting boss 32 within the range of 0.8 mm to 1.8 mm, and the thickness T1 of the bottom wall of the pole column groove 22 being greater than the thickness T2 of the top wall of the connecting boss 32, and at the same time, T1 + T2 ≥ 2.8 mm, can ensure the welding strength and welding reliability of both, thereby improving the yield rate of the battery cells.

[0048] In some embodiments, the thickness of the pole column body 21 is T, T ≥ 2 mm; the depth of the pole column groove 22 is D, 0.2T ≤ D ≤ 2T.

[0049] Specifically, the thickness T of the pole column body 21 should be greater than or equal to 2 mm, which can ensure the strength of the pole column body 21, prevent the heat generated during the welding of the bus bar to the pole column 2 from radiating to the upper plastic 4 and causing deformation or melting of the upper plastic 4, and ensure the safety performance of the battery cells.

[0050] The minimum depth D of the pole column groove 22 does not exceed 0.2T, so that it can prevent the welding marks of the pole column groove 22 and the connecting boss 32 from protruding from the pole column body 21 and affecting the bus bar welding.

[0051] In some embodiments, the distance between the outer surface of the pole column body 21 and the inner surface of the pole column connecting portion 31 is H, 4.5 mm ≤ H ≤ 5.2 mm.

[0052] With such a setting, the strength of the pole column 2 and the connecting piece 3 can be ensured. At the same time, in the traditional riveting scheme, the distance between the outer surface of the pole column and the inner surface of the pole column connecting portion of the connecting piece is in the range of 6.2 mm to 7.4 mm. In contrast, in this embodiment, the maximum distance between the outer surface of the pole column body 21 and the inner surface of the pole column connecting portion 31 is 5.2 mm, which can significantly reduce the axially occupied space.

[0053] In some embodiments, the thickness of the pole column connecting portion 31 is T3, the thickness of the pole group connecting portion 33 is T4, T2 ≥ T3 ≥ T4, the pole group connecting portion 33 is recessed from the inner surface of the pole column connecting portion 31, and 0.2 mm ≤ T4 ≤ 2 mm.

[0054] With such a setting, the thickness T2 of the connecting boss 32, the thickness T3 of the pole column connecting portion 31, and the thickness T4 of the pole group connecting portion 33 decrease in sequence, which can reduce the overall axially occupied space of the pole column 2 and the connecting piece 3.

[0055] The pole group connecting portion 33 is used to weld with the pole group 8, thereby guiding the current inside the battery to the outside.

[0056] By controlling the thickness T4 of the pole group connection part 33 within the range of 0.2 mm to 2 mm, the welding strength between the pole group connection part 33 and the pole tab 81 can be ensured. At the same time, the space occupied by the connecting piece 3 and the pole column 2 as a whole along the axial direction is reduced.

[0057] In some embodiments, the inner diameter of the second through hole 34 is larger than the inner diameter of the first through hole 23.

[0058] With such a setting, the smooth assembly of the sealant nail 10 can be ensured.

[0059] In some embodiments, the pole column groove 22 includes a first groove bottom 221 and a second groove bottom 222 in a stepped shape, and the first groove bottom 221 is recessed from the second groove bottom 222; the battery cell cover plate assembly further includes a sealant nail 10 and a welding ring 20. The sealant nail 10 includes a head and a rod portion. The head is disposed on the first groove bottom 221, and the rod portion is disposed in the liquid injection hole to seal the liquid injection hole; the welding ring 20 is disposed on the second groove bottom 222 and is located outside the sealant nail 10, and the welding ring 20 is welded to the pole column body 21.

[0060] For the sealant nail 10, after the electrolyte is filled through the liquid injection hole, the liquid injection hole is sealed by using the sealant nail 10.

[0061] The welding ring 20 is welded to the pole column 2 provided with the first through hole 23 to achieve the sealing function. At the same time, the welding area with the Busbar is enlarged to achieve overcurrent with a greater function.

[0062] With such a setting, the pole column 2 and the connecting piece 3 are limited in the mounting hole of the cover plate 1, ensuring the stability of the connection among the cover plate 1, the pole column 2, and the connecting piece 3.

[0063] In some embodiments, the pole column body 21 of the pole column 2 is disposed on the outer end surface of the mounting hole. A combined outer column surface 9 is formed between the pole column body 21 and the pole column connection part 31, and the combined outer column surface 9 is disposed in the mounting hole; the battery cell cover plate assembly further includes an upper plastic 4, a sealing ring 5, and a lower plastic 6 sleeved on the combined outer column surface 9. The upper plastic 4 is located on the outer end surface of the mounting hole to insulatively connect the pole column 2 and the cover plate 1; the sealing ring 5 is disposed between the mounting hole and the combined outer column surface 9 to sealingly connect the pole column 2 and the cover plate 1; the lower plastic 6 is located on the inner end surface of the mounting hole to insulatively connect the connecting piece 3 and the cover plate 1.

[0064] In some embodiments, the pole column 2 includes a negative pole column and a positive pole column.

[0065] The positive pole column is made of aluminum. Correspondingly, the connecting piece 3 connected to the positive pole column is also made of aluminum.

[0066] The negative pole column is made of copper. Correspondingly, the connecting piece 3 connected to the negative pole column is also made of copper.

[0067] Furthermore, regardless of whether it is the positive electrode or the negative electrode, the structures of the pole post 2 and the connecting piece 3 can be formed in one piece by stamping, without secondary processing, with simple structures and low costs.

[0068] According to an embodiment of the present invention, in a second aspect, a battery cell is further provided, including a housing 7, a pole group 8, and the battery cell cover assembly of any one of the above technical solutions. The housing 7 is provided with an open end; the pole group 8 is disposed inside the housing 7, and the pole group 8 is provided with pole tabs 81; the battery cell cover assembly is disposed at the open end of the housing 7 to encapsulate the pole group 8 inside the housing 7, and the connecting piece 3 of the battery cell cover assembly is welded to the pole group 8.

[0069] Specifically, during assembly, the connecting piece 3 is first welded to the flattened pole tab 81 of the pole group 8, then the lower plastic 6 is assembled, then it is loaded into the housing 7, and then the sealing ring 5, the upper plastic 4, and the pole post 2 are sequentially loaded at the upper end of the housing assembly. After compressing the sealing ring 5 by about 35%, the pole post 2 and the connecting piece 3 are welded and fixed by laser welding to achieve electrical connection.

[0070] The pole group 8 is used to store electrical energy.

[0071] Since the battery cell includes the battery cell cover assembly and has the same effects as the battery cell cover assembly, it will not be elaborated here.

[0072] According to an embodiment of the present invention, in a third aspect, a battery pack is further provided, including a plurality of the battery cells in the above technical solutions.

[0073] Since the battery pack includes the battery cell and has the same effects as the battery cell, it will not be elaborated here.

[0074] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery cover assembly, characterized in that: include: A cover plate, wherein the cover plate is provided with a mounting hole; A pole, the pole is arranged in the mounting hole of the cover plate, the pole comprises a pole body, the pole body is provided with a pole groove, the pole comprises a positive pole and / or a negative pole, and a bottom wall of the pole groove of one of the poles is provided with a first through hole; A connecting piece, the connecting piece is arranged on the inner side of the pole, the connecting piece includes a pole connecting part, a connecting boss protruding from the pole connecting part and a pole group connecting part connected to one side of the pole connecting part, the top wall of the connecting boss corresponds to and is welded to the bottom wall of the pole groove; the connecting boss of one of the connecting pieces is provided with a second through hole, and the second through hole corresponds to and cooperates with the first through hole to form a liquid injection hole.

2. The battery cover assembly according to claim 1, characterized in that: The thickness of the bottom wall of the pole groove is T1, the outer surface of the connecting boss is higher than the outer surface of the pole connecting portion, and the thickness of the top wall of the connecting boss is T2, 0.8mm≤T2≤1.8mm, T2≤T1, T1+T2≥2.8mm.

3. The battery cover assembly according to claim 2, characterized in that: The thickness of the pole body is T, T≥2mm; the depth of the pole groove is D, 0.2T≤D≤2T.

4. The battery cover assembly according to claim 2 or 3, characterized in that: The distance between the outer surface of the pole body and the inner surface of the pole connecting portion is H, 4.5 mm≤H≤5.2 mm.

5. The battery cell cover plate assembly according to any one of claims 1 to 3, characterized in that: The thickness of the pole connecting portion is T3, the thickness of the pole group connecting portion is T4, T2≥T3≥T4, the pole group connecting portion is recessed in the inner surface of the pole connecting portion, and 0.2mm≤T4≤2mm.

6. The battery cell cover plate assembly according to any one of claims 1 to 3, characterized in that: An inner diameter of the second through hole is greater than an inner diameter of the first through hole.

7. The battery cell cover plate assembly according to any one of claims 1 to 3, characterized in that: The pole groove comprises a first groove bottom and a second groove bottom in a stepped shape, wherein the first groove bottom is recessed in the second groove bottom; The battery cover assembly also includes: A sealing nail, the sealing nail comprising a head and a stem, the head being arranged at the bottom of the first groove, the stem being arranged at the injection hole to seal the injection hole; A welding ring is provided at the bottom of the second groove and is located outside the sealing glue nail, and the welding ring is welded to the pole body.

8. The battery cover assembly according to claim 7, characterized in that: The pole body of the pole is arranged on the outer end surface of the mounting hole, and a combined outer cylindrical surface is formed between the pole body and the pole connecting portion, and the combined outer cylindrical surface is arranged on the mounting hole; The cell cover assembly also includes: An upper plastic, the upper plastic being located on the outer end surface of the mounting hole and insulating and connecting the pole and the cover plate; A sealing ring, which is arranged between the mounting hole and the combined outer cylindrical surface to seal the pole and the cover plate; The lower plastic is located on the inner end surface of the mounting hole and insulates and connects the connecting piece and the cover plate.

9. A battery cell, characterized in that: include: a housing having an open end; A pole group, the pole group is arranged in the shell, and the pole group is provided with pole ears; The battery cell cover plate assembly according to any one of claims 1 to 8, wherein the battery cell cover plate assembly is arranged at the open end of the shell, the electrode group is encapsulated in the shell, and the connecting piece of the battery cell cover plate assembly is welded to the electrode group.

10. A battery pack, characterized in that: The invention comprises a plurality of battery cells as claimed in claim 9.

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