Laser welding cover plate structure and battery

Abstract

The laser welding cover plate structure comprises a substrate, a positive electrode assembly, a negative electrode assembly and lower plastic cement, the positive electrode assembly and the negative electrode assembly are the same in structure, and each of the positive electrode assembly and the negative electrode assembly comprises a pressing ring, upper plastic cement, a sealing ring and a pole; a bevel edge is arranged at the mounting hole of the lower plastic, and the bevel edge and the sealing ring are in compression joint to form a first seal; a turnup is arranged on the sealing ring, and the turnup of the sealing ring is extruded by the positive electrode pressing ring and the substrate to form second sealing; the pole adopts a hollow structure; according to the utility model, after the cover plate is assembled, the pole and the pressing plate are not riveted, but are directly welded, so that the working procedures are reduced. Meanwhile, the sealing ring and the positive pole inclined surface of the lower plastic are mutually compressed to form first sealing, the problem of electrolysis resistance of the cover plate can be solved, the compression ring, the substrate and the sealing ring interact to form second sealing, and meanwhile, the post terminal and the compression ring are welded to achieve candidate guarantee for preventing failure of the first sealing.

Description

Technical Field

[0001] The utility model belongs to the technical field of battery cover plate structures, and in particular relates to a laser welded cover plate structure and a battery. Background Art

[0002] The statements herein merely provide background art related to the present invention and do not necessarily constitute prior art.

[0003] With the rapid development of new energy, power batteries are increasingly widely used, and the requirements for battery cells are also constantly increasing. For square battery cells, riveted cover plates are extremely widely used. For example, Chinese utility model patent CN220439748U discloses a riveted battery cover plate, which is riveted to the pole and the pressure plate, and then the riveted edge is welded to enhance the mechanical properties and conductivity. However, the manufacturing process is complicated and the pole is relatively heavy, which is not conducive to cost control and the improvement of the energy density of the battery cell. Ordinary injection molded cover plates have many accessories, and often require injection molding and rubber coating for insulation in addition to the riveting process, resulting in a complex structure and many manufacturing processes, which is not conducive to cost control.

[0004] In addition, in order to ensure the sealing of the pole and the top cover in the prior art, multiple seals are usually provided to improve the sealing effect. For example, Chinese utility model patent CN218039481U discloses a lithium battery cover plate, which is provided with three seals to improve the sealing. However, these components require very high installation precision. When the pole and the top cover are subsequently assembled, there are problems such as complex assembly process and high cost due to too many components. Utility Model Content

[0005] The utility model aims to provide a laser-welded cover plate structure and a battery. The pole is hollowed out to ensure the mechanical and electrical properties while achieving the lightest weight and the least material use. After the cover plate is assembled, the pole and the pressure plate are no longer riveted, but are directly welded to reduce the number of steps. At the same time, in order to increase the torsion resistance of the pole, a wedge-shaped design is adopted on both sides of the welding width of the cover plate to be clamped on the base plate.

[0006] In order to achieve the above purpose, the utility model is implemented through the following technical solutions:

[0007] In the first aspect, an embodiment of the utility model provides a laser welding cover plate structure, including a substrate, a positive electrode assembly, a negative electrode assembly and a lower plastic, wherein the structures of the positive electrode assembly and the negative electrode assembly are the same, both including a pressure ring, an upper plastic, a sealing ring and a pole; a bevel is provided at the mounting hole of the lower plastic, and the bevel is crimped with the sealing ring to form a first seal; a flange is provided on the sealing ring, and the flange of the sealing ring is squeezed by the positive electrode pressure ring and the substrate to form a second seal; the pole adopts a hollow structure.

[0008] As a further technical solution, a lug is arranged on the outer circumference of the pressure ring, and a protruding groove is arranged on the inner circumference of the upper plastic, and the lug and the protruding groove cooperate with each other.

[0009] As a further technical solution, a sink is provided at the mounting hole of the positive electrode assembly or the negative electrode assembly on the substrate, and the sink cooperates with the protruding groove on the upper plastic.

[0010] As a further technical solution, the thickness of the upper plastic bottom edge is not less than 0.6 mm, and the reserved gap between the bottom edge and the sealing ring flange is not less than 0.2 mm.

[0011] As a further technical solution, the pole is provided with a bottom flange, a first step surface, a pole positioning groove and a hollow bottom of the pole.

[0012] As a further technical solution, the first step surface and the pressure ring are connected by welding.

[0013] As a further technical solution, the upper plastic is made of fully insulating material, and the insulation resistance is greater than or equal to 200MΩ; or, the upper plastic is made of insulation and conductive particles as a whole weak conductor, and the weak conductor resistance range is 50Ω-20000Ω.

[0014] As a further technical solution, the lower plastic is provided with a positive through hole and a negative through hole, the positive through hole is used to install the intermediate component, and the negative through hole is used to install the negative component.

[0015] As a further technical solution, the positive electrode through hole and the negative electrode through hole have the same structure, both including side holes and inclined sides, and the position where the sealing ring contacts the inclined side of the lower plastic forms a sealing ring compression zone.

[0016] In a second aspect, an embodiment of the utility model provides a battery, comprising the laser welded cover plate structure described in Example 1.

[0017] The beneficial effects of the above-mentioned embodiments of the utility model are as follows:

[0018] The laser welding cover plate structure provided by the utility model does not rivet the pole and the pressure plate after the cover plate is assembled, but directly welds them to reduce the number of processes. At the same time, in order to increase the torsion resistance of the pole, the pressure ring and the upper plastic welding width adopt a wedge design on both sides, which are clamped on the base plate; the sealing ring and the positive electrode slope of the lower plastic are compressed to form the first seal, which can solve the problem of electrolysis resistance of the cover plate, and the pressure ring, base plate and sealing ring interact to form the second seal. At the same time, the welding of the pole and the pressure ring can prevent the failure of the first seal as a backup guarantee.

[0019] The laser welding cover plate structure provided by the utility model has a hollow structure for the pole, and while ensuring the mechanical and electrical properties, the cover plate has the lightest weight, uses less material, and has a simpler manufacturing process; at the same time, considering that the hollow structure of the pole may affect the torsional resistance of the pole, by arranging a lug on the pressure ring, the lug on the pressure ring and the protruding groove on the upper plastic are matched and clamped on the sink on the base plate, the mechanical properties of the pole such as the torque resistance can be increased.

[0020] The laser welded cover structure provided by the utility model has a sealing ring compression zone formed at the second sealing point, which is located near the inner side of the battery cell. The sealing ring compression zone 115 is squeezed by the positive pole 114, the substrate 100 and the lower plastic 130. The compression zone formed around the pole 114 is complete, which can avoid the existence of wrinkles, compression gaps and other undesirable compression conditions. The complete sealing ring compression zone 115 can effectively block the problem of poor insulation and withstand voltage of the cover caused by the infiltration of electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0022] Figure 1 A schematic diagram of a laser welding cover plate structure provided in an embodiment of the utility model;

[0023] Figure 2 An exploded view of a laser welded cover plate structure provided in an embodiment of the utility model;

[0024] Figure 3 A schematic diagram of a positive electrode pressure ring provided in an embodiment of the utility model;

[0025] Figure 4 A schematic diagram of the plastic on the positive electrode provided in an embodiment of the utility model;

[0026] Figure 5 A schematic diagram of a substrate provided in an embodiment of the present utility model;

[0027] Figure 6 A cross-sectional view of a laser welded cover plate structure provided in an embodiment of the present utility model;

[0028] Figure 7 An enlarged view of the positive electrode assembly provided in an embodiment of the utility model;

[0029] Figure 8 A schematic diagram of the lower plastic provided in an embodiment of the utility model;

[0030] Fig. 9A schematic diagram of a positive electrode column provided in an embodiment of the utility model;

[0031] Fig.10 for Fig. 9 Cross-section view at AA in the middle.

[0032] The schematic diagram is for illustrative purposes only;

[0033] Among them, 100, substrate;

[0034] 110, positive electrode assembly; 111, positive electrode pressure ring; 112, positive electrode upper plastic; 113, sealing ring; 114, positive electrode column; 115, sealing ring compression area; 1111, left side lug; 1112, right side lug; 1121, left side protruding groove; 1122, right side protruding groove; 1001, positive electrode sinking platform; 10011, positive electrode left side sinking platform; 10013, positive electrode right side sinking platform; 1141, positive electrode bottom flange; 1142, positive electrode first step surface; 1143, positive electrode column positioning groove; 1144, positive electrode column bottom hollowing;

[0035] 120, negative electrode assembly; 121, negative electrode pressure ring; 122, negative electrode upper plastic; 123, negative electrode column;

[0036] 130, lower plastic; 1301, positive electrode through hole; 13012, positive electrode side hole; 13011, positive electrode side slope. DETAILED DESCRIPTION

[0037] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0038] Example 1

[0039] In a typical implementation of the present invention, Figure 1 As shown, a laser welding cover plate structure and a battery are provided, including a substrate 100, a positive electrode assembly 110, a negative electrode assembly 120 and a lower plastic 130. The structures of the positive electrode assembly 110 and the negative electrode assembly 120 are the same, both including a pressure ring, an upper plastic, a sealing ring 113 and a pole; a bevel is provided at the mounting hole of the lower plastic, and the bevel is crimped with the sealing ring to form a first seal; a flange is provided on the sealing ring, and the flange of the sealing ring is squeezed by the positive pressure ring and the substrate to form a second seal; the pole adopts a hollow structure.

[0040] The problem of electrolysis resistance of the cover plate can be solved by setting the first seal, and the backup guarantee after the failure of the first seal can be prevented by setting the second seal and welding the pole and the pressure ring; the weight of the cover plate and the use of materials can be reduced by adopting a hollow structure for the pole.

[0041] In this embodiment, a lug is provided on the outer circumference of the pressure ring, and a protruding groove is provided on the inner circumference of the upper plastic, the lug and the protruding groove cooperate with each other, and a sink is provided at the mounting hole of the positive electrode assembly or the negative electrode assembly on the substrate 100, and the sink cooperates with the protruding groove on the upper plastic.

[0042] In this embodiment, the thickness of the upper plastic bottom edge is not less than 0.6 mm, and the reserved gap between the bottom edge and the sealing ring flange is not less than 0.2 mm.

[0043] In this embodiment, the pole is provided with a bottom flange, a first step surface, a pole positioning groove and a hollow bottom of the pole.

[0044] In this embodiment, the first step surface and the pressure ring are connected by welding.

[0045] In this embodiment, the upper plastic is made of fully insulating material, and the insulation resistance is greater than or equal to 200MΩ; or, the upper plastic is made of insulation and conductive particles as a whole weak conductor, and the weak conductor resistance range is 50Ω-20000Ω.

[0046] In this embodiment, a positive through hole and a negative through hole are provided on the lower plastic, the positive through hole is used to install the intermediate component, and the negative through hole is used to install the negative component.

[0047] In this embodiment, the positive electrode through hole and the negative electrode through hole have the same structure, both including a side hole and an inclined side surface, and the position where the sealing ring contacts the inclined side surface of the lower plastic forms a sealing ring compression zone.

[0048] In this embodiment, the pole is made of copper-aluminum composite plate.

[0049] Since the structures of the positive electrode assembly and the negative electrode assembly are the same, the structure of the cover plate will be described in detail below by taking the positive electrode assembly as an example in conjunction with the accompanying drawings.

[0050] like Figure 2-5As shown, there are left lugs 1111 and right lugs 1112 on both sides of the positive pressure ring 111, and the plastic on the positive electrode 112 has left protruding grooves 1121 and right protruding grooves 1122 on both sides. When the positive pressure ring 111 and the plastic on the positive electrode 112 are assembled, the left lug 1111 is assembled in the left protruding groove 1121, and the right lug 1112 is assembled in the left protruding groove 1122. The left lug 1111 and the right lug 1112 can be symmetrically distributed on both sides of the positive pressure ring 111, or randomly distributed; the lug sizes can be different; the number of lugs can be greater than or equal to 1 according to needs; the lug shape can be wedge-shaped, polygonal, semicircular, etc.

[0051] The positive electrode pressure ring 111 is assembled on the positive electrode upper plastic 112, and together assembled on the positive electrode left side sink 1001 of the substrate, the left side protruding groove 1121 is assembled in the positive electrode sink 10011, and the right side protruding groove 1122 is assembled in the positive electrode right side sink 10013; the pressure ring, upper plastic and substrate can significantly increase the mechanical properties of the pole such as anti-torque through the above design.

[0052] The positive electrode plastic 112 can be made of fully insulating material with an insulation resistance greater than or equal to 200MΩ; it can also be made of insulation plus conductive particles as an overall weak conductor with a weak conductor resistance range of 50Ω to 20000Ω; generally, PPS or PI material is used to reduce the thickness change caused by the influence of welding heat on the upper plastic; the positive electrode plastic 112 and the negative electrode plastic 122 are made of different colors for easy distinction.

[0053] like Figure 6 As shown, the sealing ring 113 is encircled on the positive pole 114, and the flange of the sealing ring 113 is squeezed and deformed by the positive pressure ring 111 and the substrate 100, forming a surface compression, which constitutes the sealing structure of the positive electrode assembly 110. The thickness of the bottom edge of the plastic 112 on the positive electrode is not less than 0.6mm, and the gap between the bottom edge and the flange of the sealing ring is not less than 0.2mm, which can prevent the sealing ring from being over-compressed and causing poor sealing performance. For the full insulation requirement, the thickness of the bottom surface of the plastic on the positive electrode needs to consider the pressure breakdown, and the thickness is not less than 0.6mm.

[0054] Specifically, Figure 8 The lower plastic 130 includes a positive electrode through hole 1301, and the positive electrode through hole 1301 includes a positive electrode side hole 13012 and a positive electrode side slope 13011. Figure 7As shown, the seal ring 113 and the positive electrode slope 13011 of the lower plastic 130 are compressed to form a seal ring compression area 115. The seal ring compression area 115 is located near the inner side of the battery cell. The seal ring compression area 115 is squeezed by the positive electrode column 114, the substrate 100 and the lower plastic 130. The compression area formed around the column 114 is complete, which can avoid the existence of wrinkles, compression gaps and other undesirable compression conditions. The complete seal ring compression area 115 can effectively block the problem of poor insulation withstand voltage of the cover plate caused by the infiltration of electrolyte.

[0055] Furthermore, with the continuous development of battery cells, the models of blade batteries are constantly increasing. An important feature of blade batteries is the tabs at both ends. Inevitably, the cover plate will be immersed in the electrolyte. However, the rivet base of the currently developed riveted and minimalist cover plates cannot be completely isolated from the substrate, or small cavities or tiny creepage channels appear, which may cause a high probability of power failure in the battery cell. At present, the industry generally solves this problem by weakly conducting the positive electrode and insulating the negative electrode. This embodiment solves the above problem by extruding the positive electrode column 114, the substrate 100 and the lower plastic 130 together to form a complete sealing area 115.

[0056] like Fig. 9 and Fig.10 The positive pole 114 includes a positive bottom flange 1141, a positive first step surface 1142, a positive pole positioning groove 1143, and a positive pole bottom hollow 1144. The bottom flange width is not less than 1.5mm, and the overall shape of the bottom flange can be circular, rectangular, polygonal, etc.; the positive first step surface 1142 is welded with the pressure ring, and the step surface width is not less than 1mm; the positive pole positioning groove 1143 is convenient for processing positioning and CCD identification during use, with a size of φ0.5~φ5mm and a depth of not less than 1mm; the bottom hollow 1144 of the positive pole can be formed by stamping a plate or by machine opening. Considering the function of pole surface welding, the hollow height is affected by the residual thickness and the total height of the pole, and the residual thickness must be greater than or equal to 3mm;

[0057] Furthermore, the copper-aluminum composite plate material of the negative electrode post can reduce the use of pure copper, has cost and weight advantages, and the thickness of the copper layer is determined by the thickness of the flange.

[0058] During installation, the positive pole 113 passes through the lower plastic 130, the substrate 100, the sealing ring 113, the positive upper plastic 112, and the positive pressure ring 111 in the above-mentioned installation hole in sequence. After the installation and assembly are completed, it is necessary to use the sealing ring under the tooling to maintain a certain amount of compression, and at the same time, the positive first step surface 1142 of the positive pole 113 and the outer side of the positive pressure ring 111 are laser welded and fixed. The structure of the negative side is the same.

[0059] The above-mentioned cover plate cooperates with the opening part of the battery cell shell. The battery cell includes a cover plate, a winding core, a mylar film, a shell, etc. The winding core can be welded and fixed to the cover plate through a transition piece to achieve the purpose of current transmission; the winding core can also be directly welded and fixed to the cover plate through the pole ear to achieve current transmission; the winding core is placed in the shell, and after the cover plate and the shell are matched, a seal is formed by welding.

[0060] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A laser welded cover plate structure, characterized in that: It includes a substrate, a positive electrode assembly, a negative electrode assembly and a lower plastic. The structures of the positive electrode assembly and the negative electrode assembly are the same, both of which include a pressure ring, an upper plastic, a sealing ring and a pole. A bevel is arranged at the mounting hole of the lower plastic, and the bevel is crimped with the sealing ring to form a first seal. A flange is arranged on the sealing ring, and the flange of the sealing ring is squeezed by the positive electrode pressure ring and the substrate to form a second seal. The pole adopts a hollow structure.

2. The laser welding cover plate structure according to claim 1, characterized in that: The outer circumference of the pressure ring is provided with lugs, and the inner circumference of the upper plastic is provided with protruding grooves, and the lugs and the protruding grooves cooperate with each other.

3. The laser welded cover plate structure according to claim 2, characterized in that: A sinking platform is arranged at the mounting hole of the positive electrode assembly or the negative electrode assembly on the substrate, and the sinking platform cooperates with the protruding groove on the upper plastic.

4. The laser welded cover plate structure according to claim 1, characterized in that: The thickness of the upper plastic bottom edge is not less than 0.6 mm, and the reserved gap between the bottom edge and the sealing ring flange is not less than 0.2 mm.

5. The laser welded cover plate structure according to claim 1, characterized in that: The pole is provided with a bottom flange, a first step surface, a pole positioning groove and a hollow bottom of the pole.

6. The laser welded cover plate structure according to claim 5, characterized in that: The first step surface is connected to the pressure ring by welding.

7. The laser welded cover plate structure according to claim 1, characterized in that: The upper plastic is made of fully insulating material, and the insulation resistance is greater than or equal to 200MΩ; or, the upper plastic is made of insulation and conductive particles as a whole weak conductor, and the weak conductor resistance range is 50Ω-20000Ω.

8. The laser welded cover plate structure according to claim 1, characterized in that: The lower plastic is provided with a positive through hole and a negative through hole. The positive through hole is used to install the intermediate component, and the negative through hole is used to install the negative component.

9. The laser welded cover plate structure according to claim 8, characterized in that: The positive electrode through hole and the negative electrode through hole have the same structure, both including a side hole and an inclined side surface, and the position where the sealing ring contacts the inclined side surface of the lower plastic forms a sealing ring compression zone.

10. A battery, characterized in that: The invention comprises the laser welded cover plate structure as described in any one of claims 1 to 9.

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