Cylindrical battery monomer and battery module

Abstract

The utility model relates to the technical field of batteries, and particularly provides a cylindrical battery monomer and a battery module. The utility model relates to a cylindrical battery monomer, which comprises a shell, a battery cell and a battery cell, the electrode assembly is arranged in the shell; the cover plate is arranged at the opening, the cover plate comprises a first weak part and a second weak part, the first weak part and the second weak part are arranged at an interval, a first welding part is arranged on the inner side of the first weak part, and the first welding part is electrically connected with the electrode assembly. Under the condition that the valve is opened, the cover plate of the cylindrical battery monomer can support the roll core after the weak part is exploded, so that the roll core is prevented from being ejected out to cause short circuit. Meanwhile, the welding part is arranged on the inner side of the weak part, so that the welding of the electrode assembly and the cover plate is more sufficient, the transmission path of electrons on the electrode assembly is shortened, the internal resistance of the single cylindrical battery is reduced, and the overcurrent capability of the single cylindrical battery is enhanced.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0003] In the development of battery technology, in addition to improving the energy density of batteries, battery safety is also an issue that cannot be ignored. Therefore, how to improve battery safety is a technical problem that needs to be solved urgently in battery technology. Utility Model Content

[0004] The purpose of this utility model is to provide a cylindrical battery cell and a battery module. The cylindrical battery cell has high safety. The utility model is specifically implemented through the following technical solutions:

[0005] In a first aspect, the present invention provides a cylindrical battery cell, comprising: a shell having an opening at one end; an electrode assembly disposed in the shell; a cover plate disposed at the opening, the cover plate comprising: a first weak portion and a second weak portion, the first weak portion and the second weak portion being spaced apart, a first welding portion being provided on the inner side of the first weak portion, and the first welding portion being electrically connected to the electrode assembly.

[0006] In the above technical solution, the cover plate is provided with a first weak portion and a second weak portion, and the first weak portion and the second weak portion are spaced apart. When the cover plate is opened, the first weak portion and the second weak portion will fall off or partially fall off due to the explosion. The space between the first weak portion and the second weak portion and other portions of the cover plate can support the electrode assembly inside the battery cell to prevent the electrode assembly from being ejected, causing the electrode piece to overlap with other components and short-circuit, thereby causing serious consequences; in addition, the first welding portion electrically connected to the electrode assembly is provided on the inner side of the first weak portion. Compared with the existing weak portion where no area electrically connected to the electrode assembly is provided, the welding between the cover plate and the electrode assembly is more sufficient, the transmission path of electrons on the electrode assembly is shortened, the internal resistance of the cylindrical battery cell is reduced, and the current capacity of the cylindrical battery cell is enhanced.

[0007] In some embodiments, a second welding portion is provided between the first weak portion and the second weak portion, and the second welding portion is electrically connected to the electrode assembly.

[0008] In the above technical solution, a second welding portion is provided between the first weak portion and the second weak portion, which can increase the welding area between the cover plate and the electrode assembly and improve the flow efficiency of the battery cell.

[0009] In some embodiments, the first weak portion includes a first straight segment, a second straight segment and a first arc segment. The first straight segment and the second straight segment are both arranged along the radial direction of the cover plate, and the two ends of the arc segment are respectively connected to the first straight segment and the second straight segment.

[0010] In some embodiments, the first weak portion includes a second arc segment disposed opposite to the first arc segment, and two ends of the second arc segment are respectively connected to the first straight segment and the second straight segment.

[0011] In some embodiments, the cover plate includes a third weak portion, and the first weak portion, the second weak portion, and the third weak portion are equidistantly distributed along the circumference of the cover plate.

[0012] In some embodiments, a ratio of a maximum distance from the first weak portion to the center of the cover plate to a radius length of the cover plate is greater than or equal to 0.8 and less than or equal to 0.89.

[0013] In some embodiments, a maximum distance between the first weak portion and the center of the cover plate is greater than or equal to 18.5 mm and less than or equal to 20 mm.

[0014] In some embodiments, the thickness of the cover plate is greater than or equal to 0.35 mm and less than or equal to 0.65 mm.

[0015] In some embodiments, the second welding portion is disposed along a radial direction of the cover plate.

[0016] In some embodiments, the first welding portion includes a first protrusion and a second protrusion connected to the first protrusion, the first protrusion is arranged along the circumferential direction of the cover plate, and the second protrusion is arranged along the radial direction of the cover plate.

[0017] In some embodiments, the ratio of the maximum distance from the first welding portion and / or the second welding portion to the center of the cover plate to the diameter of the cover plate is greater than or equal to 0.65 and less than or equal to 0.85; the ratio of the minimum distance from the first welding portion and / or the second welding portion to the center of the cover plate to the diameter of the cover plate is greater than or equal to 0.2 and less than or equal to 0.45.

[0018] In some embodiments, the maximum distance from the first welding portion and / or the second welding portion to the center of the cover plate is greater than or equal to 32 mm and less than or equal to 36 mm; the minimum distance from the first welding portion and / or the second welding portion to the center of the cover plate is greater than or equal to 13 mm and less than or equal to 18 mm.

[0019] In a second aspect, the present invention further provides a battery module, which includes a plurality of the above-mentioned cylindrical battery cells.

[0020] 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

[0021] 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 considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort.

[0022] Figure 1 This is a cross-sectional view of a cylindrical battery cell provided by an embodiment of the present utility model;

[0023] Figure 2 This is a partial cross-sectional view of a cylindrical battery cell provided by an embodiment of the present utility model;

[0024] Figure 3 This is a structural diagram of a cover plate provided by an embodiment of the present utility model;

[0025] Figure 4 It is a structural schematic diagram of a cover plate provided by another embodiment of the present utility model.

[0026] List of reference numerals:

[0027] 1. Shell; 2. Electrode assembly; 3. Cover plate; 4. First weak portion; 5. Second weak portion; 6. First welding portion; 7. Second welding portion; 8. First straight segment; 9. Second straight segment; 10. First arc segment; 11. Second arc segment; 12. Third weak portion; 13. First convex portion; 14. Second convex portion. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0029] It should be noted that in the description of this utility model, terms such as "inner," "outer," "top," and "bottom" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. These are merely for ease of description and do not indicate or imply that the device or component must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] Furthermore, it should be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "installed," "set," and "connected" should be understood in a broad sense, for example, to refer to fixed connections, detachable connections, or integral connections. Those skilled in the art will understand the specific meanings of these terms in this utility model based on the specific circumstances.

[0031] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0032] Please refer to Figures 1 to 4 , Figures 1 to 4 This is a schematic structural diagram of a cylindrical battery cell provided by an embodiment of the present utility model.

[0033] like Figures 1 to 4As shown, the cylindrical battery cell of the embodiment of the present application includes: a shell 1 with an opening at one end. 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 side walls and a top wall connected to the side walls (not shown in the figure). The top wall is used to be provided with 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. In this embodiment, the shell 1 is negatively charged and the electrode terminal is positively charged. A cover plate 3 is provided at the opening of the shell 1. The cover plate 3 is electrically connected to the shell 1 and the electrode assembly 2 respectively. The cover plate 3 has the same charging polarity as the shell 1, and the cover plate 3 is also negatively charged. The applicant discovered that when the cover plate of an existing cylindrical battery cell is opened, the explosion-proof valve can burst due to excessive internal pressure, causing the area of ​​the cover plate 3 where the explosion-proof valve is located to fall off. The electrode assembly 2 can then erupt under its own gravity and pressure. The erupted electrode piece can come into contact with other battery components, causing more serious consequences such as short circuits, fires, and explosions. A common approach to addressing this issue is to provide an additional support bracket on the cover plate 3 to support the electrode assembly 2. This approach increases component cost and assembly difficulty. To address this issue, the applicant proposed a cover plate 3 with multiple weak points spaced apart. Specifically, the cover plate 3 includes a first weak point 4 and a second weak point 5, spaced apart from each other. This allows the remaining area of ​​the cover plate 3 to effectively support the electrode assembly 2 after the weak points burst. Furthermore, the applicant discovered that the area where the explosion-proof valve is located on the existing cover plate 3 is independent of the area where the welding area is located. This results in the area where the explosion-proof valve is located not being effectively welded to the corresponding tab location, resulting in a longer electron transmission path for the electrode assembly 2. To address the above issues, the applicants provided a welding area inside the weak portion, namely, a first welding portion 6 inside the first weak portion 4. This allows for a more complete welding between the cover plate 3 and the electrode assembly 2, shortens the electron transmission path on the electrode assembly 2, reduces the internal resistance of the cylindrical battery cell, and enhances the current carrying capacity of the cylindrical battery cell.

[0034] Further reference Figure 2 To the attached Figure 4In this embodiment, a second welded portion 7 is provided between the first weak portion 4 and the second weak portion 5. The second welded portion 7 is electrically connected to the electrode assembly 2, fully utilizing the position of the cover plate 3 and increasing the welding area between the cover plate 3 and the electrode assembly 2. In this embodiment, to reduce manufacturing difficulty and save manufacturing costs, the first weak portion 4 and the second weak portion 5 are configured to have the same shape and are evenly distributed on the cover plate 3, which is not limited here. The following describes the shape of the first weak portion 4 as an example. The first weak portion 4 includes a first straight segment 8, a second straight segment 9, and a first curved segment 10. The ends of the first curved segment 10 are respectively connected to the first straight segment 8 and the second straight segment 9. The first straight segment 8 and the second straight segment 9 are both arranged along the radial direction of the cover plate 3, forming a semi-enclosed shape with an opening. In some embodiments, the first weak portion 4 also includes a second curved segment 11. The second curved segment 11 is arranged opposite the first curved segment 10. The ends of the second curved segment 11 are respectively connected to the first straight segment 8 and the second straight segment 9, making the shape of the first weak portion 4 closed. Furthermore, the cover plate 3 of the present invention includes a third weak portion 12. The first weak portion 4, the second weak portion 5, and the third weak portion 12 are equidistantly spaced along the circumference of the cover plate 3. That is, the distances between the first weak portion 4 and the second weak portion 5, the distances between the second weak portion 5 and the third weak portion 12, and the distances between the third weak portion 12 and the first weak portion 4 are equal, thereby enhancing the weld smoothness of the cover plate 3. In this embodiment, the ratio of the maximum distance of the first weak portion 4 from the center of the cover plate 3 to the radius of the cover plate 3 is greater than or equal to 0.8 and less than or equal to 0.89. Optionally, the ratio of the maximum distance of the first weak portion 4 from the center of the cover plate 3 to the radius of the cover plate 3 can be 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, or 0.89, as long as the valve opening area of ​​the weak portion is ensured. Preferably, the ratio of the maximum distance of the first weak portion 4 from the center of the cover plate 3 to the radius of the cover plate 3 is 0.84. In some embodiments, the maximum distance between the first weak portion 4 and the center of the cover plate 3 is greater than or equal to 18.5 mm and less than or equal to 20 mm. Optionally, the maximum distance between the first weak portion 4 and the center of the cover plate 3 can be 18.5 mm, 19 mm, 19.5 mm or 20 mm. Preferably, the maximum distance between the first weak portion 4 and the center of the cover plate 3 is 19 mm. Furthermore, the thickness of the cover plate 3 is greater than or equal to 0.35 mm and less than or equal to 0.65 mm. Optionally, the thickness of the cover plate 3 can be 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm or 0.65 mm, as long as the welding requirements of the cover plate 3, the shell 1 and the electrode assembly 2 are met. Preferably, the thickness of the cover plate 3 is 0.5 mm. In some embodiments, the second welding portion 7 is arranged along the radial direction of the cover plate 3 to ensure that each circle of electrode pieces can be effectively welded to the cover plate 3.Furthermore, the first weld portion 6 includes a first protrusion 13 and a second protrusion 14, which are connected to each other. The first protrusion 13 is arranged along the circumference of the cover plate 3, and the second protrusion 14 is arranged along the radial direction of the cover plate 3. This fully utilizes the area within the first weak portion 4, the second weak portion 5, or the third weak portion 12, thereby increasing the weld area. Furthermore, the ratio of the maximum distance from the first weld portion 6 to the center of the cover plate 3 to the diameter of the cover plate 3 is greater than or equal to 0.65 and less than or equal to 0.85, and / or the ratio of the maximum distance from the second weld portion 7 to the center of the cover plate 3 to the diameter of the cover plate 3 is greater than or equal to 0.65 and less than or equal to 0.85. Optionally, the ratio of the maximum distance from the first weld portion 6 to the center of the cover plate 3 to the diameter of the cover plate 3 may be 0.65, 0.7, 0.75, 0.8, or 0.85, and / or the ratio of the maximum distance from the second weld portion 7 to the center of the cover plate 3 to the diameter of the cover plate 3 may be 0.65, 0.7, 0.75, 0.8, or 0.85. Preferably, the ratio of the maximum distance from the first weld portion 6 to the center of the cover plate 3 to the diameter of the cover plate 3 is 0.75, and / or the ratio of the maximum distance from the second weld portion 7 to the center of the cover plate 3 to the diameter of the cover plate 3 is 0.8. Furthermore, the maximum distance from the first weld portion 6 to the center of the cover plate 3 is greater than or equal to 32 mm and less than or equal to 36 mm, and / or the maximum distance from the second weld portion 7 to the center of the cover plate 3 is greater than or equal to 32 mm and less than or equal to 36 mm. Optionally, the maximum distance from the first welding portion 6 to the center of the cover plate 3 may be 32 mm, 33 mm, 34 mm, 35 mm, or 36 mm, and / or the maximum distance from the second welding portion 7 to the center of the cover plate 3 may be 32 mm, 33 mm, 34 mm, 35 mm, or 36 mm. Preferably, the maximum distance from the first welding portion 6 to the center of the cover plate 3 is 34 mm, and / or the maximum distance from the second welding portion 7 to the center of the cover plate 3 is 35 mm.

[0035] The present invention 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, and are not described in detail here.

[0036] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection 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 cover plate is provided at the opening, and the cover plate comprises: A first weak portion and a second weak portion, wherein the first weak portion and the second weak portion are spaced apart from each other, a first welding portion is disposed inside the first weak portion, and the first welding portion is electrically connected to the electrode assembly.

2. The cylindrical battery cell according to claim 1, characterized in that: A second welding portion is provided between the first weak portion and the second weak portion, and the second welding portion is electrically connected to the electrode assembly.

3. The cylindrical battery cell according to claim 1, characterized in that: The first weak portion includes a first straight line segment, a second straight line segment and a first arc segment. The first straight line segment and the second straight line segment are both arranged along the radial direction of the cover plate. Two ends of the arc segment are respectively connected to the first straight line segment and the second straight line segment.

4. The cylindrical battery cell according to claim 3, characterized in that: The first weak portion includes a second arc segment, which is arranged opposite to the first arc segment, and two ends of the second arc segment are respectively connected to the first straight line segment and the second straight line segment.

5. The cylindrical battery cell according to claim 1, characterized in that: The cover plate includes a third weak portion, and the first weak portion, the second weak portion and the third weak portion are equidistantly distributed along the circumference of the cover plate.

6. The cylindrical battery cell according to claim 1, characterized in that: A ratio of a maximum distance from the first weak portion to the center of the cover plate to a radius length of the cover plate is greater than or equal to 0.8 and less than or equal to 0.

89.

7. The cylindrical battery cell according to claim 6, characterized in that: The maximum distance between the first weak portion and the center of the cover plate is greater than or equal to 18.5 mm and less than or equal to 20 mm.

8. The cylindrical battery cell according to claim 1, characterized in that: The thickness of the cover plate is greater than or equal to 0.35 mm and less than or equal to 0.65 mm.

9. The cylindrical battery cell according to claim 2, characterized in that: The second welding portion is arranged along the radial direction of the cover plate.

10. The cylindrical battery cell according to claim 2, characterized in that: The first welding portion includes a first convex portion and a second convex portion connected to the first convex portion, the first convex portion is arranged along the circumferential direction of the cover plate, and the second convex portion is arranged along the radial direction of the cover plate.

11. The cylindrical battery cell according to claim 10, characterized in that: The ratio of the maximum distance from the first welding part and / or the second welding part to the center of the cover plate to the diameter of the cover plate is greater than or equal to 0.65 and less than or equal to 0.85; the ratio of the minimum distance from the first welding part and / or the second welding part to the center of the cover plate to the diameter of the cover plate is greater than or equal to 0.2 and less than or equal to 0.

45.

12. The cylindrical battery cell according to claim 11, characterized in that: The maximum distance from the first welding part and / or the second welding part to the center of the cover plate is greater than or equal to 32 mm and less than or equal to 36 mm; the minimum distance from the first welding part and / or the second welding part to the center of the cover plate is greater than or equal to 13 mm and less than or equal to 18 mm.

13. A battery module, characterized in that: The invention comprises a plurality of cylindrical battery cells according to any one of claims 1 to 12.

Images