Battery shell and single battery

Abstract

The utility model provides a battery shell and a single battery, the battery shell comprises a bottom shell with an opening end, and the bottom shell is provided with a welding reference surface along the opening end; the top cover is arranged on the bottom shell and used for blocking the opening end, the top cover is in lap joint with the welding datum plane, a sealing face annularly arranged along the opening end is arranged on the inner side of the top cover, and the sealing face abuts against or is attached to the inner wall of the bottom shell and / or the welding datum plane; a welding seam between the top cover and the bottom shell is positioned in a sealing surface area; an annular groove is annularly formed in the top cover along the opening end, and the area, corresponding to the annular groove, on the inner side face of the top cover belongs to a sealing face. According to the utility model, the welding seam of the top cover and the bottom shell can be arranged close to one side of the annular sealing groove as much as possible, and the upper preassembled flange and the lower preassembled flange can be cut as much as possible under the condition that the sealing performance is not changed, so that the volume of the battery shell is reduced to a certain extent; and the energy density of the single battery applied to the battery shell is favorably improved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery casing and a single battery cell. Background Technology

[0002] Existing lithium-ion battery structures typically include a bottom case and a top cover welded together to form a sealed cavity for housing the battery cells.

[0003] Chinese patent CN215644674U discloses a battery casing and a battery. The battery casing includes a bottom shell and a top cover. The bottom shell includes a connected bottom wall and an annular side wall. The side wall has an opening at one end away from the bottom wall. The top cover is placed on the end face of the opening, and a side cover is arranged around the outside of the opening. The annular side cover and the top cover are welded together. The top cover has a weld seam on the side away from the side cover. The weld seam includes multiple connected and partially overlapping welded segments.

[0004] In the aforementioned patent, in order to ensure that the top cover and bottom shell have a sufficiently large contact area for welding, the side cover is wider. This results in a larger radial dimension of the battery casing on the side wall, which in turn increases the volume of the individual battery cell. Under the same volume, the energy density of the individual battery cell formed by this battery casing is low. Utility Model Content

[0005] In view of the shortcomings of the prior art, the first objective of this utility model is to provide a battery casing in which the weld between the top cover and the bottom cover is closer to the center of the top cover in the radial direction of the bottom cover, which is beneficial to reducing the size of the battery casing.

[0006] The second objective of this invention is to provide a single-cell battery that is small in size and has a high energy density.

[0007] The embodiments of this utility model are achieved through the following technical solutions:

[0008] A battery casing includes: a bottom shell having an open end, wherein a welding reference surface is circumferentially provided on the bottom shell along the open end; a top cover disposed on the bottom shell for sealing the open end, the top cover overlapping the welding reference surface, and a sealing surface circumferentially provided on the inner side of the top cover along the open end, the sealing surface abutting or fitting against the inner wall of the bottom shell and / or the welding reference surface; the top cover is welded to the bottom shell, the weld between the two being located within the sealing surface area; the top cover has an annular groove circumferentially provided along the open end, and the area on the inner side of the top cover corresponding to the annular groove belongs to the sealing surface. Thus, the area of ​​the sealing surface corresponding to the annular groove allows the gap between the sealing surface and the inner wall of the bottom shell and / or the welding reference surface to be reduced or eliminated, the weld between the top cover and the bottom shell to be located as close as possible to the annular sealing groove side, and, without changing the sealing performance, as much of the upper and lower pre-installed flanges as possible can be cut, thereby reducing the volume of the battery casing to a certain extent and improving the energy density of the individual battery cells used in this battery casing.

[0009] According to a preferred embodiment, the annular groove is disposed on the outer side of the top cover, and the annular groove is recessed toward the bottom shell.

[0010] According to a preferred embodiment, the depth of the annular groove is H = 0.3mm-0.4mm, the maximum width of the annular groove is D, D = 0.9mm-1.0mm, and D / H = 2.25-3.33.

[0011] According to a preferred embodiment, the annular groove is a circular arc groove.

[0012] According to a preferred embodiment, an arc-shaped transition section is formed between the welding reference surface and the inner wall of the bottom shell, and the sealing surface is close to or attached to the arc-shaped transition section; the arc-shaped transition section is arc-shaped with a radius of R, R = 0.28mm-0.32mm, and R / H = 0.7-1.067.

[0013] According to a preferred embodiment, the weld is arranged around the annular groove, and the minimum distance between the weld and the center of the bottom of the annular groove is L, where L = 0.2 mm - 0.3 mm.

[0014] According to a preferred embodiment, the weld is arranged around the annular groove, and part or all of the weld is located on the inner wall of the annular groove.

[0015] According to a preferred embodiment, the open end of the bottom shell is provided with a lower pre-mounted flange extending outward in a horizontal direction, and the area on the top cover located outside the annular groove forms an upper pre-mounted flange corresponding to the lower pre-mounted flange. There is a venting gap between the upper pre-mounted flange and the lower pre-mounted flange, and the venting gap extends to the outer edge of the weld.

[0016] A single-cell battery includes a cell and a battery casing, wherein the cell is disposed within the battery casing. This single-cell battery exhibits high safety and a higher energy density compared to existing batteries of the same type and volume. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A three-dimensional structural schematic diagram of the battery casing provided in an embodiment of this utility model;

[0019] Figure 2 This is an exploded structural diagram of the battery casing provided in an embodiment of the present utility model;

[0020] Figure 3 A top view of the battery casing provided in an embodiment of this utility model;

[0021] Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure at section AA;

[0022] Figure 5 for Figure 4 A magnified view of the structure at point B in the middle;

[0023] Figure 6 This invention provides an alternative assembly structure for the top cover and bottom shell of a battery casing, as described in an embodiment of the present invention.

[0024] Icons: 1-Top cover, 10-Upper pre-installed flange, 11-Annular groove, 12-Sealing surface, 2-Bottom shell, 20-Lower pre-installed flange, 21-Arc-shaped transition section, 22-Welding reference surface, 3-Escape gap, 4-Welding area. Detailed Implementation

[0025] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0026] In the description of this utility model, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0028] Please refer to Figures 1 to 6 A battery casing includes a bottom shell 2 and a top cover 1. The bottom shell 2 has an open end, and a welding reference surface 22 is provided around the open end. The top cover 1 is disposed on the bottom shell 2 to seal the open end. The top cover 1 overlaps the welding reference surface 22, and a sealing surface 12 is disposed on the inner side of the top cover 1, which is arranged around the open end. The sealing surface 12 abuts against or adheres to the inner wall of the bottom shell 2 and / or the welding reference surface 22. The top cover 1 is welded to the bottom shell 2, and the weld between them is located within the area of ​​the sealing surface 12. The top cover 1 has an annular groove 11 around the open end, and the area on the inner side of the top cover 1 corresponding to the annular groove 11 belongs to the sealing surface 12. Figure 1 and Figure 2 The image shows the blank state of the battery casing provided in this embodiment. Specifically, for ease of assembly, the open end of the bottom shell 2 is provided with a lower pre-mounted flange 20 extending outward in the horizontal direction. The area on the top cover 1 outside the annular groove 11 forms an upper pre-mounted flange 10 corresponding to the lower pre-mounted flange 20. The weld path extends along the annular groove 11. After the bottom shell 2 and the top cover 1 are welded, the upper pre-mounted flange 10 and the lower pre-mounted flange 20 outside the weld are cut to form the battery casing. In this embodiment, the area of ​​the sealing surface 12 corresponding to the annular groove 11 can reduce or eliminate the gap between the sealing surface 12 and the inner wall of the bottom shell 2 and / or the welding reference surface 22. Thus, during the welding process of the top cover 1 and the bottom shell 2, the weld can be set as close as possible to the annular sealing groove. After welding, the upper pre-mounted flange 10 and the lower pre-mounted flange 20 can be cut as much as possible without changing the sealing performance, which reduces the volume of the battery casing to a certain extent and is beneficial to improving the energy density of the single battery cell used in this battery casing.

[0029] In this embodiment, both the bottom shell 2 and the top cover 1 are manufactured using a stamping process. The annular groove 11 here can improve the strength of the top cover 1. At the same time, the annular groove 11 is distributed close to the edge of the opening end of the bottom shell 2, so it has little impact on the volume of the inner cavity of the bottom shell 2 and does not affect the assembly of the battery cells inside the battery casing.

[0030] In this embodiment, an annular groove 11 is provided on the outer side of the top cover 1, and the annular groove 11 is recessed towards the bottom shell 2.

[0031] like Figure 5 As shown, the depth of the annular groove 11 is H, where H = 0.3mm-0.4mm, and the maximum width of the annular groove 11 is D, where D = 0.9mm-1.0mm, and D / H = 2.25-3.33, preferably D / H = 3. This design ensures a sufficiently large contact area between the sealing surface 12 and the bottom shell 2 while reducing the volume occupied by the annular groove 11 within the bottom shell 2's internal cavity. This ensures a tight weld between the top cover 1 and the bottom shell 2, reducing the battery casing volume without affecting cell assembly.

[0032] Optionally, the annular groove 11 can be a circular arc groove. This facilitates stamping, and at the same time, the stress concentration at the edge of the annular groove 11 is small, resulting in higher strength of the top cover 1.

[0033] like Figure 5 and Figure 6 As shown, an arc-shaped transition section 21 is formed between the welding reference surface 22 and the inner wall of the bottom shell 2, and the sealing surface 12 abuts or fits against the arc-shaped transition section 21. In this embodiment, it can be understood that the area of ​​the arc-shaped transition section 21 near the welding reference surface 22 belongs to the welding reference surface 22, and the area of ​​the arc-shaped transition section 21 near the inner wall of the bottom shell 2 belongs to the inner wall of the bottom shell 2. Here, the arc-shaped transition section 21 is convenient to be adapted to the aforementioned arc-shaped annular groove 11. Preferably, the sealing surface 12 fits against the arc-shaped transition section 21. It should be noted that the fitting of the sealing surface 12 and the arc-shaped transition section 21 here means that there are areas of mutual contact between the sealing surface 12 and the arc-shaped transition section 21, that is, there are areas belonging to the sealing surface 12 and areas belonging to the arc-shaped transition section 21 that fit against each other, and it is not required that the entire area of ​​the sealing surface 12 fits against the entire area of ​​the arc-shaped transition section 21.

[0034] Of course, in another embodiment, the sealing surface 12 and the arc-shaped transition section 21 are also allowed to be in a non-adherent state. In this case, the gap between the two is required to be small enough not to affect the laser welding.

[0035] In the above scenario, in order to further reduce the volume of the battery casing, preferably, the sealing surface 12 is fitted to the side of the arc transition section 21 near the inner wall of the casing, that is, the sealing surface 12 is fitted to the inner wall of the bottom casing 2, so that the weld can be closer to the center direction of the top cover 1, which means that more of the upper pre-mounted flange 10 and the lower pre-mounted flange 20 can be cut.

[0036] In this embodiment, as Figure 5 As shown, the arc-shaped transition section 21 is arc-shaped with a radius of R, where R = 0.28mm-0.32mm and R / H = 0.7-1.067, preferably R / H = 1. Thus, the annular groove 11 sinks the bottom shell 2 to a sufficient depth in the longitudinal direction to ensure a sufficiently large mating area between the sealing surface 12 and the arc-shaped transition section 21 (which can be used for the welding area 4 in welding operations) without affecting the assembly of the battery cells inside the bottom shell 2.

[0037] like Figure 6 As shown, in some embodiments, a venting gap 3 extends between the upper pre-mounted flange 10 and the lower pre-mounted flange 20 to the outer edge of the weld. During welding, especially during penetration welding, a large amount of heat is generated on the top cover 1 and the bottom shell 2. The air between the top cover 1 and the bottom shell 2 is heated and expands. The venting gap 3 helps this high-temperature air to escape to the outside of the battery casing, preventing it from carrying weld slag through the gap between the top cover 1 and the bottom shell 2 and entering the battery casing, causing a short circuit. At the same time, during laser welding, the venting gap 3 also provides more venting channels for hot air in the keyhole or molten pool, helping to reduce porosity and improve weld quality.

[0038] like Figure 5 and 6 As shown, the weld is arranged around the annular groove 11, and the minimum distance between the weld and the bottom center of the annular groove 11 is L, where L = 0.2mm-0.3mm, preferably L = 0.2mm.

[0039] Optionally, the weld is arranged circumferentially along the annular groove 11, with part or all of the weld located on the inner wall of the annular groove 11. Preferably, the entire weld is located on the inner wall of the annular groove 11. Figure 5 and Figure 6 As shown, welding is performed within welding area 4. Specifically, welding can be performed by projecting a laser beam onto the side of the annular groove 11 or onto the outer wall of the bottom shell 2. When welding from the side of the annular groove 11, the keyhole penetrates the side wall of the top cover 1, and may or may not penetrate the side wall of the bottom shell 2; when welding from the side of the bottom shell 2, the keyhole penetrates the side wall of the bottom shell 2, and may or may not penetrate the side wall of the top cover 1.

[0040] With the annular groove 11 provided, the weld seam on the top cover 1 side is located within the annular groove 11, and its overall height is lower than the highest height of the upper side of the top cover 1. Therefore, no further processing of this weld seam is required, such as rolling operations, simplifying the production process of the individual battery cells using this battery casing. Correspondingly, on the bottom shell 2 side, the weld seam is located at the transition between the lower pre-mounted flange 20 and the outer wall of the bottom shell 2, which is a concave arc structure. Therefore, the weld seam on the bottom shell 2 side also does not require further processing, further simplifying the production process.

[0041] It should be noted that, in some embodiments, preferably, the welding area 4 is located at the transition between the upper edge of the bottom shell 2 and the lower pre-installed flange 20. The aforementioned escaping gap 3 connects to the welding area 4.

[0042] This embodiment also provides a single battery cell, including a cell (not shown in the figure) and the aforementioned battery casing, with the cell disposed within the battery casing. Due to the high sealing performance and small size of the aforementioned battery casing, this single battery cell exhibits high safety and a greater energy density compared to similar batteries of the same type and volume in the prior art.

[0043] This embodiment also provides a method for producing a single-cell battery, applied to the aforementioned single-cell battery, comprising the following steps:

[0044] Step S1: Place the battery cell inside the bottom shell 2 and cover the top cover 1 at the opening end of the bottom shell 2;

[0045] Step S2: Bring the sealing surface 12 close to or adhere it to the inner wall of the bottom shell 2 and / or the welding reference surface 22;

[0046] Step S3: Weld the top cover 1 and the bottom shell 2, with the welding path close to or within the area of ​​the annular groove 11 to form a weld.

[0047] Step S4: Cut off the excess material on the outside of the weld of the top cover 1 and the bottom shell 2.

[0048] Thus, the area of ​​the sealing surface 12 corresponding to the annular groove 11 can reduce or eliminate the gap between the sealing surface 12 and the bottom shell 2. After the top cover 1 and the bottom shell 2 are welded, the weld can be set as close as possible to the side of the annular sealing groove, or set in the area of ​​the annular groove 11, so that as much of the area outside the weld on the battery casing can be cut off as much as possible without changing the sealing performance, thereby reducing the volume of the battery casing and improving the energy density of the single battery cell.

[0049] Preferably, the battery casing is welded using laser welding.

[0050] Preferably, the top cover 1 and the bottom shell 2 are welded together through the metal.

[0051] The technical means disclosed in this utility model are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications are also considered within the scope of protection of this utility model.

Claims

1. A battery case characterized by comprising: include: A bottom shell has an open end, and a welding reference surface is provided around the open end of the bottom shell; A top cover is disposed on the bottom shell and is used to seal the opening end. The top cover overlaps the welding reference surface. A sealing surface is disposed on the inner side of the top cover along the opening end. The sealing surface abuts against or fits against the inner wall of the bottom shell and / or the welding reference surface. The top cover is welded to the bottom shell, and the weld between the two is located within the sealing surface area; The top cover has an annular groove around the opening end, and the area on the inner side of the top cover corresponding to the annular groove belongs to the sealing surface.

2. The battery case according to claim 1, characterized by The annular groove is provided on the outer side of the top cover, and the annular groove is recessed towards the bottom shell.

3. The battery case according to claim 1 or 2, characterized by The depth of the annular groove is H = 0.3mm-0.4mm, and the maximum width of the annular groove is D, where D = 0.9mm-1.0mm and D / H = 2.25-3.

33.

4. The battery casing according to claim 1 or 2, characterized in that, The annular groove is a circular arc groove.

5. The battery casing according to claim 1 or 2, characterized in that, An arc-shaped transition section is formed between the welding reference surface and the inner wall of the bottom shell, and the sealing surface is close to or attached to the arc-shaped transition section; the arc-shaped transition section is arc-shaped with a radius of R, R = 0.28mm-0.32mm, R / H = 0.7-1.

067.

6. The battery casing according to claim 5, characterized in that, The weld is arranged around the annular groove, and the minimum distance between the weld and the center of the bottom of the annular groove is L, where L = 0.2mm - 0.3mm.

7. The battery case of claim 5, wherein, The weld is arranged around the annular groove, and part or all of the weld is located on the inner wall of the annular groove.

8. The battery casing according to claim 1, characterized in that, The bottom shell has an open end with a lower pre-mounted flange extending outward in a horizontal direction. The area on the top cover outside the annular groove forms an upper pre-mounted flange corresponding to the lower pre-mounted flange. There is a venting gap between the upper pre-mounted flange and the lower pre-mounted flange, and the venting gap extends to the outer edge of the weld.

9. A single cell characterized by It includes a battery cell and a battery housing as described in any one of claims 1-8, wherein the battery cell is disposed within the battery housing.

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