Cylindrical battery monomer and battery module

Abstract

The utility model relates to the technical field of batteries, particularly provides a cylindrical battery monomer, and aims to solve the technical problems that the welding efficiency of a cover plate and a shell of the cylindrical battery monomer is low, the cost is high, and the air leakage risk of penetration welding of a current collecting component and the cover plate is high. Therefore, the cylindrical single battery provided by the utility model comprises a shell with an opening at one end; the electrode assembly is arranged in the shell; the first plate body is arranged at the opening, and the first plate body is electrically connected with the shell and the electrode assembly respectively; the second plate body is arranged on the side, away from the electrode assembly, of the first plate body, and the second plate body is electrically connected with the first plate body. The first plate body is electrically connected with the shell and the electrode assembly, and the second plate body is electrically connected with the first plate body, so that the welding process of the first plate body and the second plate body with the shell is simplified, the part and assembly cost is reduced, and the production and manufacturing efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and specifically provides a cylindrical battery monomer 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] With the continuous upgrading of market demand, cylindrical batteries have developed from 18650 and 21700 to the larger and more energy-dense 4680 series cylindrical batteries. Compared with 18650 and 21700 cylindrical cells, the 4680 cylindrical battery adopts a full-ear design, which effectively shortens the current path, promotes smoother movement of electrons inside the battery, reduces the internal resistance of the cell itself, and significantly reduces Joule heat loss. In addition, cylindrical batteries are made of stainless steel, have higher mechanical strength, and can effectively absorb the pressure caused by the expansion of the negative electrode, so they are more suitable for high-silicon and high-nickel systems.

[0004] The negative electrode of the current mainstream large cylindrical battery structure has a current collecting component. Usually, after the cover plate and the shell are welded to close the opening, the cover plate and the current collecting component are laser penetrated and welded. However, the welding efficiency of the cover plate and the shell is low and the cost is high; at the same time, the risk of gas leakage in the penetration welding between the current collecting component and the cover plate is high. Therefore, the above problems need to be solved urgently. Utility Model Content

[0005] The utility model aims to solve the above technical problems, namely, to solve the technical problems of low efficiency and high cost of welding between the cover plate and the shell of a cylindrical battery cell and high risk of gas leakage in penetration welding between the current collecting component and the cover plate.

[0006] In a first aspect, the utility model provides a cylindrical battery cell, comprising: a shell having an opening at one end; an electrode assembly disposed in the shell; a first plate disposed at the opening, the first plate being electrically connected to the shell and the electrode assembly respectively; a second plate disposed on a side of the first plate away from the electrode assembly, the second plate being electrically connected to the first plate.

[0007] In the above technical solution, by electrically connecting the first plate to the shell and the electrode assembly respectively, and the second plate to the first plate, the welding process of the first plate and the second plate to the shell is simplified, the cost of parts and assembly is reduced, and the efficiency of production is improved.

[0008] In some embodiments, the first plate body includes a first connecting portion and a second connecting portion, the first connecting portion is electrically connected to the shell, and the second connecting portion is electrically connected to the second plate body and the electrode assembly, respectively.

[0009] In some embodiments, the second connecting part is a circular plate, the first connecting part includes a first vertical part and an extension part, the two ends of the first vertical part are respectively connected to the second connecting part and the extension part, the extension part surrounds the first outer peripheral surface of the first vertical part and is electrically connected to the shell.

[0010] In some embodiments, there is a gap between the first vertical portion and the side wall of the housing.

[0011] In the above technical solution, the first outer peripheral surface of the first vertical portion is clearance-matched with the inner wall surface of the side wall of the shell, so that there is a movable margin between the first vertical portion and the shell, thereby improving the assembly efficiency of the first plate body and the second plate body.

[0012] In some embodiments, the side wall of the shell includes an outer end surface surrounding the opening, and the inner surface of the extension portion is welded to the outer end surface.

[0013] In the above technical solution, the inner surface of the extension portion is welded to the outer end surface, which reduces the difficulty of welding the shell and the first plate.

[0014] In some embodiments, a maximum distance between the first end surface of the extension portion and the outer wall surface of the side wall is less than or equal to 0.15 mm.

[0015] In the above technical solution, the maximum distance between the first end surface of the extension portion and the outer wall surface of the side wall is less than or equal to 0.15 mm, thereby improving the welding yield of the extension portion and the side wall.

[0016] In some embodiments, the second plate body includes a second plate body and a protrusion surrounding the second plate body, and the protrusion protrudes from an inner surface of the second plate body facing the electrode assembly.

[0017] In the above technical solution, the convex portion is arranged to protrude from the inner surface of the second plate body, which can enhance the overall strength of the second plate body.

[0018] In some embodiments, the first plate body and the second plate body are interference fit, the convex portion includes a second vertical portion and a horizontal portion, the second outer peripheral surface of the second vertical portion abuts the inner peripheral surface of the first vertical portion, and the horizontal portion abuts the second connecting portion.

[0019] In the above technical solution, the first plate body and the second plate body are interference fit, and the welding yield is high. During laser welding, the second plate body can prevent the laser from passing through the gap and damaging the second plate body.

[0020] In some embodiments, a distance from the first outer surface of the horizontal portion to the electrode assembly is smaller than a distance from the second outer surface of the extending portion to the electrode assembly.

[0021] In some embodiments, a distance from the second end surface of the second vertical portion to the electrode assembly is smaller than a distance from the second outer surface of the extension portion to the electrode assembly.

[0022] In the above technical solution, the second end face of the second vertical portion is closer to the electrode assembly than the second outer surface of the extension portion, reserving expansion space for the second plate body. In this way, after assembly is completed, when the second plate body expands, its dimensional tolerance still meets the design requirements.

[0023] In some embodiments, the thickness of the first plate is greater than or equal to 0.3 mm and less than or equal to 0.65 mm; and / or the thickness of the second plate is greater than or equal to 0.2 mm and less than or equal to 0.65 mm.

[0024] In the above technical solution, if the thickness of the first plate is set too thin, it will be detrimental to the welding of the first plate and the shell, and if it is set too thick, it will lead to poor welding with the pole ear; if the thickness of the second plate is set too thin, it will affect the deformation and thus affect the valve opening area, and if it is set too thick, it will increase the cost.

[0025] In some embodiments, the material of the first plate is the same as that of the shell; and / or the material of the first plate is the same as that of the second plate.

[0026] In the above technical solution, the material of the first plate and the shell is set to be the same; and / or the material of the first plate and the second plate is set to be the same, which can reduce the difficulty of welding between the first plate, the second plate and the shell and enhance the overall strength.

[0027] In some embodiments, the shell, the first plate and the second plate are all made of low carbon steel.

[0028] In the above technical solution, the shell, the first plate and the second plate are made of low-carbon steel, which reduces the internal resistance of the battery cell structure.

[0029] In some embodiments, the first plate body and the second plate body are fixed by welding; and / or, the first plate body and the second plate body are fixed by bonding.

[0030] In the above technical solution, the first plate body and the second plate body are fixed by welding or bonding, which can simplify the process and reduce the difficulty of production.

[0031] In a second aspect, the utility model further provides a battery module, wherein the battery module comprises a plurality of the above-mentioned cylindrical battery cells.

[0032] The advantages of the battery module and the cylindrical battery cell described above over the prior art are the same, and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. 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 related drawings can be obtained based on these drawings without creative work:

[0034] Figure 1 is a cross-sectional view of a cylindrical battery cell provided by an embodiment of the utility model;

[0035] Figure 2 It is a partial cross-sectional view of a cylindrical battery cell provided by an embodiment of the utility model;

[0036] Figure 3 yes Figure 2 A schematic diagram of the structure with a partial enlargement at the center;

[0037] Figure 4 yes Figure 2 A partial exploded view of the .

[0038] List of reference numerals:

[0039] 1. Shell; 11. Side wall; 111. Inner wall surface; 112. Outer end surface; 113. Outer wall surface; 2. Electrode assembly; 3. First plate body; 31. First connecting portion; 311. First vertical portion; 3111. First peripheral surface; 312. Extension portion; 3121. Inner surface; 3122. First end surface; 3123. Second outer surface; 32. Second connecting portion; 4. Second plate body; 41. Second plate body; 42. Protrusion; 421. Second vertical portion; 4211. Second peripheral surface; 4212. Second end surface; 422. Horizontal portion; 4221. First outer surface. DETAILED DESCRIPTION

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] Please refer to Figures 1 to 4 , Figures 1 to 4 A schematic diagram of the structure of a cylindrical battery cell provided in an embodiment of the utility model.

[0045] like Figures 1 to 4 As shown, the cylindrical battery cell of the embodiment of the present application includes: a shell 1, one end of which has an opening. In this embodiment, the shell 1 is a hollow structure with an opening on one side, which is used to accommodate the electrode assembly 2 and the electrolyte. The electrode assembly 2 is arranged in the accommodating cavity of the shell 1. The shell 1 includes a side wall 11 and a top wall (not shown in the figure) connected to the side wall 11. The top wall is used to be arranged on components such as electrode terminals. The shape of the shell 1 can be determined according to the specific shape of the electrode assembly 2. In this embodiment, the electrode assembly 2 is a cylindrical structure, and the shell 1 is selected as a cylindrical shell 1. The shell 1 can be positively charged, negatively charged, or uncharged. The first plate 3 is arranged at the opening of the shell 1, and the first plate 3 is electrically connected to the shell 1 and the electrode assembly 2 respectively. In this embodiment, the shell 1 is directly connected to the electrode assembly 2, and the shell 1 is charged. Optionally, the first plate 3 and the shell 1 can be connected by welding, so that the first plate 3 and the shell 1 can have substantially the same potential. The second plate body 4 is arranged on a side of the first plate body 3 away from the electrode assembly 2, and the first plate body 3 and the second plate body 4 are electrically connected. In the present embodiment, the second plate body 4 is electrically connected to the first plate body 3 but not directly to the shell 1, which simplifies the welding process of the first plate body 3, the second plate body 4 and the shell 1, improves production efficiency and reduces manufacturing costs.

[0046] In the present embodiment, the first plate body 3 includes a first connection portion 31 and a second connection portion 32, the second connection portion 32 is a circular plate body, which forms inner and outer surfaces that are arranged oppositely and in parallel along the thickness direction, the inner surface of the second connection portion 32 is electrically connected to the electrode assembly 2, and the outer surface of the second connection portion 32 is electrically connected to the second plate body 4. Optionally, the second connection portion 32 is connected to the electrode assembly 2 and the second plate body 4 respectively by laser welding, or other connection methods can be used to ensure the effect of tight connection and good sealing performance, which is not limited in this embodiment. Further, the first connection portion 31 is arranged around the outer periphery of the second connection portion 32, and the first connection portion 31 is electrically connected to the shell 1. Optionally, the first connection portion 31 is connected to the shell 1 by laser welding, or other connection methods can be used to ensure the effect of tight connection and good sealing performance, which is not limited in this embodiment.

[0047] In this embodiment, the first connection portion 31 includes a first vertical portion 311 and an extension portion 312. The first vertical portion 311 is extended along the center line direction of the cylindrical battery. One end of the first vertical portion 311 is connected to the second connection portion 32, and the other end is connected to the extension portion 312. In some embodiments, the side of the first vertical portion 311 away from the center of the cylindrical battery is a first outer peripheral surface 3111, and there is a gap between the first outer peripheral surface 3111 of the first vertical portion 311 and the inner wall surface 111 of the side wall 11 of the shell 1. The extension portion 312 is arranged in a direction perpendicular to the first vertical portion 311 and surrounds the first outer peripheral surface 3111 of the first vertical portion 311. The extension portion 312 is electrically connected to the shell 1. Optionally, the second connection portion 32 is connected to the electrode assembly 2 and the second plate body 4 respectively by laser welding, and other connection methods can also be used to ensure a tight connection and good sealing performance. In some embodiments, the side of the side wall 11 of the shell 1 surrounding the opening is the outer end face 112, and the side of the extension 312 facing the side wall 11 is the inner surface 3121. The inner surface 3121 of the extension 312 is welded to the outer end face 112, so that the shell 1 and the first plate 3 are connected as a whole. Optionally, the first connecting portion 31 and the shell 1 are connected by laser welding, or other connection methods can be used to ensure a tight connection and good sealing performance. Specifically, the laser is irradiated along the inner surface 3121 of the extension 312 and the outer end face 112 of the side wall 11, and the laser radiation heats the surface to be processed. The surface heat diffuses to the inside through heat conduction, so that the surface of the workpiece melts and forms a specific molten pool, and then the extension 312 and the side wall 11 of the shell 1 are welded as a whole. In some embodiments, the side of the extension portion facing away from the center of the first plate body 3 is a first end face 3122, and the maximum distance between the first end face 3122 of the extension portion 312 and the outer wall surface 113 of the side wall 11 is less than or equal to 0.15 mm, and can be 0 mm, 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm or 0.15 mm.

[0048] In this embodiment, the second plate body 4 includes a second plate body 41 and a convex portion 42 surrounding the second plate body 41, and the convex portion 42 protrudes from the inner surface of the second plate body 41 facing the electrode assembly 2. The second plate body 41 is a circular plate-shaped structure, and the convex portion 42 is an annular structure surrounding the outside of the second plate body 41. The convex portion 42 is processed on the second plate body 4 and protrudes relative to the second plate body 4 facing the electrode assembly 2. In some embodiments, the first plate body 3 and the second plate body 4 are interference-fitted, that is, the convex portion 42 and the second plate body 4 are interference-fitted. The convex portion 42 includes a second vertical portion 421 and a horizontal portion 422, the second outer peripheral surface 4211 of the second vertical portion 421 abuts against the inner peripheral surface of the first vertical portion 311, and the horizontal portion 422 abuts against the second connecting portion 32. The interference fit can increase the connection strength between the first plate body 3 and the second plate body 4 and improve the sealing performance. At the same time, the first plate body 3 and the second plate body 4 are interference-fitted, and no external equipment is required to fix the first and second plate bodies 4, which simplifies the assembly process. Optionally, the second outer peripheral surface 4211 of the second vertical portion 421 and the inner peripheral surface of the first vertical portion 311 are connected by laser welding. During welding, the laser is irradiated on the connection, and the laser partially melts and connects them together to achieve sealing, thereby reducing the risk of electrolyte leakage from the connection. In some embodiments, the side of the horizontal portion 422 facing away from the electrode assembly 2 is the first outer surface 4221, and the side of the extension portion 312 facing away from the electrode assembly 2 is the second outer surface 3123. The distance from the first outer surface 4221 of the horizontal portion 422 to the electrode assembly 2 is less than the distance from the second outer surface 3123 of the extension portion 312 to the electrode assembly 2. In other embodiments, the side of the second vertical portion 421 facing away from the electrode assembly 2 is the second end surface 4212, and the distance from the second end surface 4212 of the second vertical portion 421 to the electrode assembly 2 is less than the distance from the second outer surface 3123 of the extension portion 312 to the electrode assembly 2.

[0049] In the present embodiment, the thickness of the first plate body 3 is greater than or equal to 0.3 mm and less than or equal to 0.65 mm. Optionally, the thickness of the first plate body 3 is 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm or 0.65 mm. The thickness of the first plate body 3 is selected to ensure the connection strength of the first plate body 3 and not affect the welding effect and the flow rate. This embodiment is not limited here. In some embodiments, the thickness of the second plate body 4 is greater than or equal to 0.2 mm and less than or equal to 0.65 mm. Optionally, the thickness of the second plate body 4 is 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm and 0.65 mm. The thickness of the second plate body 4 is selected to ensure the connection strength of the second plate body 4 and not affect the welding effect and the flow rate. This embodiment is not limited here.

[0050] In this embodiment, the first plate 3 is made of the same material as the shell 1, which can ensure the connection strength with the shell 1, and the first plate 3 can also provide good support for the electrode assembly 2. Optionally, the shell 1 is made of low-carbon steel, the first plate 3 is low-carbon steel, and the second plate 4 is stainless steel. In some embodiments, the second plate 4 is made of the same material as the first plate 3 to ensure the connection strength of the first plate 3 and the second plate 4. Optionally, the shell 1 is made of low-carbon steel, and the first plate 3 and the second plate 4 are made of stainless steel. Further, the shell 1, the first plate 3 and the second plate 4 are made of the same material. Preferably, the shell 1, the first plate 3 and the second plate 4 are made of low-carbon steel or stainless steel.

[0051] In this embodiment, the first plate body 3 and the second plate body 4 are fixed by welding. Optionally, the first plate body 3 and the second plate body 4 are fixed by laser welding, or other connection methods can be used to ensure a tight connection and good sealing performance. In some embodiments, the first plate body 3 and the second plate body 4 are fixed by bonding. Optionally, the first plate body 3 and the second plate body 4 are fixed by structural adhesive, or other connection methods can be used to ensure a tight connection and good sealing performance. This embodiment is not limited here.

[0052] The utility model also provides a battery module having a plurality of cylindrical battery cells. The beneficial effects of the battery module are the same as the advantages of the cylindrical battery cells in this embodiment over the prior art, which will not be described in detail here.

[0053] 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 cylindrical battery cell, characterized in that: include: A housing having an opening at one end; An electrode assembly is disposed in the housing; A first plate body, disposed at the opening, the first plate body being electrically connected to the housing and the electrode assembly respectively; The second plate body is arranged on a side of the first plate body away from the electrode assembly, and the second plate body is electrically connected to the first plate body.

2. The cylindrical battery cell according to claim 1, characterized in that: The first plate body includes a first connecting portion and a second connecting portion, the first connecting portion is electrically connected to the shell, and the second connecting portion is electrically connected to the second plate body and the electrode assembly, respectively.

3. The cylindrical battery cell according to claim 2, characterized in that: The second connecting part is a circular plate, the first connecting part includes a first vertical part and an extension part, two ends of the first vertical part are respectively connected to the second connecting part and the extension part, the extension part surrounds the first outer peripheral surface of the first vertical part and is electrically connected to the shell.

4. The cylindrical battery cell according to claim 3, characterized in that: A gap is defined between the first vertical portion and the side wall of the housing.

5. The cylindrical battery cell according to claim 3, characterized in that: The side wall of the shell includes an outer end surface surrounding the opening, and the inner surface of the extension portion is welded to the outer end surface.

6. The cylindrical battery cell according to claim 5, characterized in that: A maximum distance between the first end surface of the extension portion and the outer wall surface of the side wall is less than or equal to 0.15 mm.

7. The cylindrical battery cell according to claim 3, characterized in that: The second plate body includes a second plate body and a convex portion surrounding the second plate body, wherein the convex portion protrudes from an inner surface of the second plate body facing the electrode assembly.

8. The cylindrical battery cell according to claim 7, characterized in that: The first plate body is interference fit with the second plate body, the convex portion includes a second vertical portion and a horizontal portion, the second outer peripheral surface of the second vertical portion abuts against the inner peripheral surface of the first vertical portion, and the horizontal portion abuts against the second connecting portion.

9. The cylindrical battery cell according to claim 8, characterized in that: A distance from a first outer surface of the horizontal portion to the electrode assembly is smaller than a distance from a second outer surface of the extending portion to the electrode assembly.

10. The cylindrical battery cell according to claim 9, characterized in that: The distance from the second end surface of the second vertical portion to the electrode assembly is smaller than the distance from the second outer surface of the extension portion to the electrode assembly.

11. The cylindrical battery cell according to claim 1, characterized in that: The thickness of the first plate is greater than or equal to 0.3 mm and less than or equal to 0.65 mm; and / or the thickness of the second plate is greater than or equal to 0.2 mm and less than or equal to 0.65 mm.

12. The cylindrical battery cell according to claim 1, characterized in that: The material of the first plate is the same as that of the shell; and / or the material of the first plate is the same as that of the second plate.

13. The cylindrical battery cell according to claim 12, characterized in that: The shell, the first plate and the second plate are all made of low-carbon steel.

14. The cylindrical battery cell according to claim 1, characterized in that: The first plate body and the second plate body are fixed by welding; and / or the first plate body and the second plate body are fixed by bonding.

15. A battery module, characterized in that: A cylindrical battery cell comprising any one of claims 1 to 14.

Images