Cover plate assembly, battery monomer and battery module

Abstract

The utility model relates to the technical field of batteries, particularly provides a cover plate assembly for a single battery, the single battery and a battery module, and aims to solve the technical problems that a cover plate liquid injection hole sealing assembly of the single battery is difficult to assemble, and a liquid injection channel interferes with an electrode assembly in the assembly process to scratch a diaphragm. Therefore, the cover plate assembly for the battery monomer comprises a cover plate, a plurality of liquid injection holes and a plurality of liquid injection holes, the first end of the flanging part is connected with the cover plate along the edge of the liquid injection hole, and the second end of the flanging part is provided with a first fillet. Compared with the flanging part of which the second end is a right-angle side, in the process of assembling the cover plate to the single battery, the flanging part can be prevented from interfering with a roll core hole in the electrode assembly to scratch a diaphragm of the electrode assembly, so that short circuit or electric leakage of a positive electrode and a negative electrode is avoided, and safety accidents such as overheat, fire, explosion and the like of the battery are avoided; and meanwhile, the damage of the diaphragm can cause mixing and reaction of materials in the battery, so that the capacitance is reduced, the bearing capacity is reduced and the performance is reduced.

Description

Technical Field

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

[0002] Lithium-ion batteries have outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide adaptability, and small self-discharge coefficient. They are one of the most widely used batteries in the world today and an important part of the development of new energy.

[0003] In the prior art, when injecting electrolyte into a lithium-ion battery, the top cover of the battery is opened and then the electrolyte is injected. After the injection is completed, a sealing nail is used to seal the injection hole, and then the sealing nail is welded to the cover plate by laser welding to achieve the sealing of the cover plate. Alternatively, an aluminum sheet is directly covered on the injection hole, and the aluminum sheet and the injection hole on the cover plate are sealed and welded. However, the above-mentioned injection hole sealing structure is complex in form, process and cost. The sealing nail is welded to the injection hole. Since electrolyte is easily residual around the injection hole, it is easy to cause poor welding problems such as cold welding of the sealing nail, pores and cracks, and the sealing nail welding is easy to deform. Therefore, the sealing reliability of the injection hole sealing structure is relatively low. In addition, the sealing plastic nail does not cooperate well with the injection hole due to aging, resulting in the risk of it falling into the interior of the secondary battery.

[0004] In order to solve the above problems, a hard seal is usually used to seal the injection hole without the need for sealing pin welding. However, it is difficult to assemble the hard seal seal and the injection hole. At the same time, in the process of installing the cover plate to the battery cell, avoiding interference between the injection channel and the electrode assembly is also a technical problem that needs to be solved urgently. Utility Model Content

[0005] The utility model aims to solve the above technical problems, namely, to solve the technical problems that the sealing assembly of the liquid injection hole of the cover plate of the battery cell is difficult to assemble, and the liquid injection channel interferes with the electrode assembly and scratches the diaphragm during the assembly process.

[0006] In a first aspect, the utility model provides a cover plate assembly for a battery cell, comprising: a cover plate provided with a liquid injection hole; a flange portion, a first end of which is connected to the cover plate along an edge of the liquid injection hole, and a second end of the flange portion has a first rounded corner.

[0007] In the above technical solution, the second end of the flange portion has a first rounded corner. Compared with the flange portion with a right-angled side at the second end, during the process of assembling the cover plate to the battery cell, the flange portion can be prevented from interfering with the winding core hole in the electrode assembly, thereby scratching the diaphragm of the electrode assembly, causing the positive and negative electrodes to short-circuit or leak, causing safety accidents such as battery overheating, fire, and explosion; at the same time, damage to the diaphragm will also cause mixing and reaction of materials inside the battery, resulting in reduced capacity, reduced carrying capacity, or reduced performance.

[0008] In some embodiments, the radius of the first rounded corner is greater than or equal to 0.1 mm and less than or equal to 0.6 mm.

[0009] In the above technical solution, if the radius of the first fillet is set too small or too large, the production difficulty of the first fillet will be increased, thereby increasing the manufacturing cost and reducing the production efficiency.

[0010] In some embodiments, a connection between the flange portion and the cover plate has a second rounded corner.

[0011] In the above technical solution, a second fillet is provided at the connection between the flange portion and the cover plate. When the seal is installed at the injection hole, the second fillet can play a guiding role, facilitating the assembly of the seal.

[0012] In some embodiments, the radius of the second rounded corner is greater than or equal to 0.6 mm and less than or equal to 2.5 mm.

[0013] In the above technical solution, if the radius of the second fillet is set too small, the production difficulty of the second fillet will increase, thereby increasing manufacturing costs and reducing production efficiency; if the radius of the second fillet is set too large, the size of the flange portion will become shorter, affecting the sealing effect.

[0014] In some embodiments, the length of the flange portion is greater than or equal to 3 mm and less than or equal to 6 mm, and / or the thickness of the flange portion is greater than or equal to 0.1 mm and less than or equal to 0.6 mm.

[0015] In the above technical solution, if the length of the flange is set too short, it will affect the sealing effect, and if it is set too long, it will increase the cost of raw materials; if the thickness of the flange is set too thin, the seal and the flange may break when there is an interference fit between them.

[0016] In some embodiments, the diameter of the injection hole is greater than or equal to 2.5 mm and less than or equal to 5 mm.

[0017] In the above technical solution, if the diameter of the injection hole is set too small, the injection efficiency of the electrolyte will be affected. At the same time, when welding the positive electrode, the welding needle needs to be inserted into the electrode assembly through the injection hole. If the diameter of the injection hole is set too small, the insertion of the welding needle will be difficult. If the diameter of the injection hole is set too large, the corresponding battery cell hole of the electrode assembly will also increase, which will affect the overall energy density of the electrode assembly.

[0018] In some embodiments, the cover plate assembly includes a seal, which is disposed at the injection hole, and an interference fit between the seal and the injection hole is greater than or equal to 0.05 mm and less than or equal to 0.4 mm.

[0019] In the above technical solution, the interference fit between the seal and the injection hole is set too large, resulting in poor sealing; the interference fit between the seal and the injection hole is set too small, resulting in poor manufacturing reliability.

[0020] In some embodiments, the sealing member is spherical, and the ratio of the diameter of the sealing member to the diameter of the injection hole is greater than or equal to 1.01 and less than or equal to 1.2.

[0021] In the above technical solution, the seal is set to be spherical, which can enhance the sealing effect with the injection hole; if the ratio of the diameter of the seal to the diameter of the injection hole is set too large or too small, it will affect the sealing effect of the seal and the injection hole.

[0022] In some embodiments, the sealing component is made of metal material or polymer material.

[0023] In a second aspect, the utility model also provides a battery cell, including the above-mentioned cover plate assembly, the battery cell has an electrode assembly, the electrode assembly has a winding core hole, and the distance difference between the hole wall and the flange portion of the winding core hole is greater than or equal to 0.1 mm and less than or equal to 2 mm.

[0024] In the above technical solution, the difference in distance between the hole wall of the core hole and the flange portion is too small, and the core hole will interfere with the extension of the flange portion and further injection of liquid. The difference between the hole wall of the core hole and the flange portion is too large. When the size of the electrode assembly is certain, it will affect the aperture of the injection hole, and then affect the injection efficiency of the electrolyte. At the same time, when welding the positive electrode, the welding needle needs to be inserted into the electrode assembly through the injection hole. The diameter of the injection hole is set too small, and the insertion of the welding needle is difficult.

[0025] The advantages of the battery cell and the above-mentioned cover plate assembly over the prior art are the same and will not be described in detail here.

[0026] In a third aspect, the utility model further provides a battery module, which includes a plurality of the above-mentioned battery cells.

[0027] The advantages of the battery module and the cylindrical battery cell mentioned above over the prior art are the same and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only illustrate certain embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 It is a schematic diagram of the structure of a battery cell provided by an embodiment of the utility model;

[0030] Figure 2 It is a structural schematic diagram of a cover plate assembly provided by an embodiment of the utility model;

[0031] Figure 3 It is a partial cross-sectional view of a battery cell provided by an embodiment of the utility model;

[0032] Figure 4 It is a structural schematic diagram of a cover plate provided by an embodiment of the utility model;

[0033] List of reference numerals:

[0034] 1. Cover plate assembly; 2. Cover plate; 3. Liquid injection hole; 4. Flanged edge; 5. First fillet; 6. Second fillet; 7. Seal; 8. Electrode assembly; 9. Winding core hole; 10. Shell; 11. Top wall; 12. Side wall; 13. Pole. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0036] It should be noted that in the description of the present invention, the terms "inside", "outside", "top", "bottom" and other terms indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third", and "fourth" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0037] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation", "setting" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0039] Please refer to Figures 1 to 4 , Figures 1 to 4 A schematic structural diagram of a cover plate assembly 1 for a battery cell and a battery cell provided in an embodiment of the utility model.

[0040] like Figures 1 to 4As shown, the cover plate assembly 1 includes a cover plate 2. In this embodiment, the shape of the cover plate 2 is adapted to the shape of the battery cell. For example, the battery cell is a cylindrical battery cell, and the shape of the cover plate 2 is circular. The cover plate 2 is provided with an injection hole 3. In this embodiment, the injection hole 3 is arranged at the center of the cover plate 2. The cover plate assembly 1 includes a flange portion 4, and the first end of the flange portion 4 is connected to the cover plate 2 along the edge of the injection hole 3. In some embodiments, the flange portion 4 can be welded to the cover plate 2 or formed integrally with the cover plate 2. The second end of the flange portion 4 has a first fillet 5, that is, the metal material at the second end of the flange portion 4 is processed into the first fillet 5 using a cutting tool. Compared with the flange portion 4 with a right-angled edge at the second end, the flange portion 4 can be prevented from interfering with the winding core hole 9 in the electrode assembly 8 during the assembly of the cover plate 2 to the battery cell, thereby scratching the diaphragm of the electrode assembly 8, causing the positive and negative electrodes to short-circuit or leak electricity, causing safety accidents such as battery overheating, fire, and explosion; at the same time, the damage of the diaphragm will also cause the mixing and reaction of the internal materials of the battery, resulting in reduced capacitance, reduced carrying capacity, and reduced performance. Further, the radius of the first fillet 5 is set to be greater than or equal to 0.1 mm and less than or equal to 0.6 mm; optionally, the radius of the first fillet 5 can be set to 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm and 0.6 mm; preferably, the radius of the first fillet 5 is set to 0.3 mm. In this embodiment, the connection between the flange portion 4 and the cover plate 2 has a second fillet 6, and when the seal 7 is installed at the injection hole 3, the second fillet 6 can play a guiding role to facilitate the assembly of the seal 7. Further, the radius of the second fillet 6 is greater than or equal to 0.6 mm and less than or equal to 2.5 mm; optionally, the radius of the second fillet 6 can be set to 0.6 mm, 0.7 mm, 0.8 mm...2.4 mm or 2.6 mm; preferably, the radius of the second fillet 6 can be set to 0.8 mm. In some embodiments, the length of the flange portion 4 is greater than or equal to 3 mm and less than or equal to 6 mm; optionally, the length of the flange portion 4 can be set to 3 mm, 4 mm, 5 mm or 6 mm; preferably, the length of the flange portion 4 can be set to 5 mm. Further, the diameter of the injection hole 3 is greater than or equal to 2.5 mm and less than or equal to 5 mm; optionally, the diameter of the injection hole 3 can be set to 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm; preferably, the diameter of the injection hole 3 can be set to 3.5 mm. In this embodiment, the cover plate assembly 1 further includes a sealing member 7, which is disposed at the injection hole 3. After the battery cell is injected with liquid, the sealing member 7 is disposed at the injection hole 3 to prevent leakage of liquid or gas. The interference between the sealing member 7 and the injection hole 3 is greater than or equal to 0.05 mm and less than or equal to 0.4 mm. The interference refers to the dimensional tolerance between the sealing member 7 and the injection hole 3, and the interference determines the tightness of the sealing member 7 installed to the injection hole 3.Optionally, the interference between the seal 7 and the injection hole 3 can be set to 0.05 mm, 0.1 mm, 0.2 mm...0.4 mm. In some embodiments, the seal 7 is spherical, and the hard seal between the sphere and the flange portion 4 can enhance the sealing effect; the ratio of the diameter of the seal 7 to the diameter of the injection hole 3 is greater than or equal to 1.01 and less than or equal to 1.2, and the seal 7 and the injection hole 3 have an interference fit, which is easy to assemble. Optionally, the diameter ratio of the seal 7 and the injection hole 3 can be set to 1.01, 1.02, 1.03...1.1, 1.2. Furthermore, the material of the seal 7 is a metal material or a polymer material. Optionally, the material of the seal 7 can be carbon steel, other metal materials or composite polymer materials.

[0041] like Figures 1 to 4 As shown, the cylindrical battery cell of the embodiment of the present application includes: a shell 10, one end of which has an opening. In the present embodiment, the shell 10 is a hollow structure with an opening on one side, which is used to accommodate the electrode assembly 8 and the electrolyte cavity, and the electrode assembly 8 is arranged in the accommodating cavity of the shell 10. The shape of the shell 10 can be determined according to the specific shape of the electrode assembly 8. In the present embodiment, the electrode assembly 8 is a cylindrical structure, and the shell 10 is selected as a cylindrical shell 10. The shell 10 can be positively charged, negatively charged, or uncharged. The cover plate assembly 1 is arranged at the opening of the shell 10, and the cover plate assembly 1 is electrically connected to the shell 10 and the electrode assembly 8 respectively. In the present embodiment, the shell 10 is directly connected to the electrode assembly 8, and the shell 10 is charged. Optionally, the cover plate assembly 1 and the shell 10 can be connected by welding, so that the cover plate assembly 1 and the shell 10 can have substantially the same potential.

[0042] In this embodiment, if Figures 1 to 4As shown, in this embodiment, the shell 10 includes a side wall 12 and a top wall 11, and the top wall 11 is arranged opposite to the opening and connected to the side wall 12. The side wall 12 and the top wall 11 can be an integrally formed structure, that is, the shell 10 is an integrally formed component. In addition, the side wall 12 and the top wall 11 can also be two components arranged separately, and then connected together by welding or the like, which is not limited here. The side wall 12 is a cylindrical structure, and the top wall 11 is a plate-like structure, and its shape corresponds to the shape of the side wall 12. An opening is formed at one end of the side wall 12, and the top wall 11 is connected to the other end of the side wall 12 away from the opening. In some embodiments, the top wall 11 has an electrode lead-out hole, and the pole 13 is insulated and arranged on the top wall 11. The pole 13 can be fixed as a whole on the outside of the top wall 11, or it can extend into the interior of the shell 10 through the electrode lead-out hole. In this embodiment, an electrode lead-out hole for installing the pole 13 is formed on the top wall 11 by a hole-opening process. The top wall 11 is formed by processing the shell 10. The setting of the electrode lead-out hole will not affect the flatness of the top wall 11, and enhance the connection strength between the top wall 11 and the busbar. The top wall 11 and the pole 13 can be used as two output poles of the cylindrical battery cell, simplifying the structure of the cylindrical battery cell and ensuring the current capacity of the cylindrical battery cell. The top wall 11 and the pole 13 are arranged at the same end of the cylindrical battery terminal, so that the busbar can be assembled to the same side, simplifying the assembly process and improving the efficiency of assembling multiple cylindrical battery cells into groups. In some embodiments, the electrode assembly 8 has a positive pole ear and a negative pole ear, the positive pole ear is connected to the pole 13, and the negative pole ear is connected to the cover plate assembly 1; it is also possible that the positive pole ear is connected to the cover plate assembly 1, and the negative pole ear is connected to the pole 13. When the positive pole tab is connected to the pole 13 and the negative pole tab is connected to the cover assembly 1, the pole 13 is the positive output pole of the cylindrical battery cell and the cover assembly 1 is the negative output pole of the cylindrical battery cell; when the positive pole tab is connected to the cover assembly 1 and the negative pole tab is connected to the pole 13, the pole 13 is the negative output pole of the cylindrical battery cell and the cover assembly 1 is the positive output pole of the cylindrical battery cell. The positive pole tab and the negative pole tab are arranged at both ends of the electrode assembly 8, which can reduce the risk of conduction between the positive and negative pole tabs and increase the flow area of ​​the positive pole tab and the flow area of ​​the negative pole tab.

[0043] The utility model also provides a battery module having a plurality of battery cells. The beneficial effects of the battery module are the same as the advantages of the battery cells in this embodiment over the prior art, and will not be described in detail here.

[0044] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A cover plate assembly for a battery cell, characterized in that: include: A cover plate, wherein the cover plate is provided with a liquid injection hole; A flange portion, wherein a first end of the flange portion is connected to the cover plate along an edge of the liquid injection hole, and a second end of the flange portion has a first rounded corner.

2. The cover plate assembly for a battery cell according to claim 1, characterized in that: The radius of the first fillet is greater than or equal to 0.1 mm and less than or equal to 0.6 mm.

3. The cover plate assembly for a battery cell according to claim 1, characterized in that: A connection between the flange portion and the cover plate has a second rounded corner.

4. The cover plate assembly for a battery cell according to claim 3, characterized in that: The radius of the second fillet is greater than or equal to 0.6 mm and less than or equal to 2.5 mm.

5. The cover plate assembly for a battery cell according to claim 3, characterized in that: The length of the flange portion is greater than or equal to 3 mm and less than or equal to 6 mm, and / or the thickness of the flange portion is greater than or equal to 0.1 mm and less than or equal to 0.6 mm.

6. The cover plate assembly for a battery cell according to claim 1, characterized in that: The diameter of the injection hole is greater than or equal to 2.5 mm and less than or equal to 5 mm.

7. The cover plate assembly for a battery cell according to claim 5, characterized in that: The cover plate assembly includes a sealing member, which is disposed at the liquid injection hole, and an interference fit between the sealing member and the liquid injection hole is greater than or equal to 0.05 mm and less than or equal to 0.4 mm.

8. The cover plate assembly for a battery cell according to claim 7, characterized in that: The sealing member is spherical, and the ratio of the diameter of the sealing member to the diameter of the injection hole is greater than or equal to 1.01 and less than or equal to 1.

2.

9. The cover plate assembly for a battery cell according to claim 7, characterized in that: The sealing element is made of metal material or polymer material.

10. A battery cell, characterized in that: Comprising the cover plate assembly according to any one of claims 1 to 9, the battery cell has an electrode assembly, the electrode assembly has a winding core hole, and the distance difference between the hole wall of the winding core hole and the flange portion is greater than or equal to 0.1 mm and less than or equal to 2 mm.

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

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