Battery bottom cover, battery shell and single battery

Abstract

The utility model belongs to the field of a primary battery box of a single battery or a battery pack, and particularly relates to a battery bottom cover, a battery shell and a single battery. In order to solve the technical problem that the internal structure of a battery is damaged due to the fact that a negative electrode cover plate in the prior art is of a flat plate structure, the negative electrode cover plate is thicker and needs to be welded with larger power, the utility model provides a battery bottom cover which comprises a flat plate part and a welding part upwards protruding out of the flat plate part, the upper end face of each welding part is higher than the upper plate face of the flat plate part and forms a welding face used for being connected with a negative electrode lug in a welded mode, and the thickness of each welding part is smaller than that of the flat plate part. The utility model also provides a battery shell and a single battery using the battery bottom cover. And on the basis of not thinning the flat plate part, the welding part is thinned, so that the effect of ensuring the structural strength of the battery bottom cover while reducing the welding power is achieved.

Description

Technical Field

[0001] The utility model belongs to the field of primary battery boxes for single batteries or battery packs, and particularly relates to a battery bottom cover, a battery housing and a single battery. Background Art

[0002] Batteries are widely used in various products such as digital cameras, computers, mobile phones, etc. In the prior art, a battery generally includes a battery housing, a battery top cover, a battery cell, a negative current collector plate and a positive current collector plate. The battery housing includes a battery bottom cover and a housing body. The battery cell, the negative current collector plate and the positive current collector plate are arranged inside the battery housing. The negative electrode tab of the battery cell is welded to the negative current collector plate (or negative transfer piece), and the positive electrode tab of the battery cell is welded to the positive current collector plate (or positive transfer piece). When the materials of the battery housing are different, the battery bottom cover is welded to different current collector plates. For example, when the battery housing is an aluminum shell, the battery bottom cover is welded to the positive current collector plate (such as the cylindrical battery in the Chinese utility model patent with the authorization publication number CN220856711U and the authorization publication date of April 26, 2024); when the battery housing is a steel shell, the battery bottom cover is welded to the negative current collector plate.

[0003] The battery housing can be a cylindrical housing. For example, in the cylindrical battery in the above-mentioned Chinese utility model patent with the authorization publication number CN220856711U, the battery bottom cover is a circular cover; the battery housing can also be a regular prismatic housing. For example, in the regular prismatic battery disclosed in the Chinese utility model patent with the authorization publication number CN217134494U and the authorization publication date of August 5, 2022, in the regular prismatic battery, the battery bottom cover is a regular polygon cover, and the negative electrode tab of the battery cell is directly led out from the top of the battery cell and connected to the negative terminal, and the positive electrode tab of the battery cell is led out from the bottom of the battery cell and connected to the positive terminal through the battery housing. The positive terminal and the negative terminal are used to connect to the electrical equipment.

[0004] Since when electrically connecting the battery bottom cover and the corresponding electrode tabs, it is necessary to first weld the corresponding electrode tabs to the corresponding current collector plates and then weld the corresponding current collector plates to the battery bottom cover, a total of two weldings are required, resulting in a low welding yield of the battery.

[0005] To solve the above problems, the Chinese utility model patent with the authorization publication number CN218632366U and the authorization publication date of March 14, 2023 discloses a battery, in which the negative electrode tab of the battery is directly welded to the negative cover plate (i.e., the battery bottom cover) by resistance welding or torque welding.

[0006] However, in the above-mentioned Chinese utility model patent, since the negative electrode cover plate has a flat structure, when the strength of the negative electrode cover plate meets the strength requirements of the battery case, the negative electrode cover plate is usually relatively thick. To ensure the welding effect, a relatively large power must be used for welding. However, the relatively large welding power also increases the risk of the tab of the electrode assembly being welded through, resulting in a decrease in the welding yield. To solve this problem, if the thickness of the negative electrode cover plate is simply reduced, although welding can be performed with a relatively small power, the strength of the negative electrode cover plate will not meet the strength requirements of the battery case, and the negative electrode cover plate is prone to deformation during welding, affecting the welding yield and product quality.

[0007] According to the analysis in the first paragraph of the background art, in the above-mentioned utility model patent, the battery case is a steel case, and the negative electrode cover plate (i.e., the battery bottom cover) is welded to the negative current collector plate. Correspondingly, when the negative electrode cover plate (i.e., the battery bottom cover) in the above-mentioned battery is transferred to an aluminum case battery and the battery bottom cover is directly welded to the positive tab, the above-mentioned problems will also occur. Summary of the Invention

[0008] The purpose of the present invention is to provide a battery bottom cover to solve the technical problems that in the prior art, since the battery bottom cover has a flat structure, the battery bottom cover is usually relatively thick. To ensure the welding effect, a relatively large power must be used for welding. However, the relatively large welding power also increases the risk of the tab of the electrode assembly being welded through, resulting in a decrease in the welding yield. If the thickness of the battery bottom cover is simply reduced, although welding can be performed with a relatively small power, the strength of the battery bottom cover will not meet the strength requirements of the battery case, and the battery bottom cover is prone to deformation during welding, affecting the welding yield and product quality.

[0009] The purpose of the present invention is also to provide a battery case to solve the above-mentioned same technical problems.

[0010] The purpose of the present invention is also to provide a single cell battery to solve the above-mentioned same technical problems.

[0011] To achieve the above purpose, the technical solution of the battery bottom cover provided by the present invention is:

[0012] A battery bottom cover includes a flat plate portion and at least one welding portion protruding upward from the flat plate portion. The upper end surfaces of the welding portions are all higher than the upper plate surface of the flat plate portion and form welding surfaces for welding connection with the negative tab or the positive tab. The thickness of each welding portion is less than the thickness of the flat plate portion.

[0013] Further, the battery bottom cover is a circular cover.

[0014] Further, the battery bottom cover is a regular polygon cover.

[0015] Further, there are at least two welding parts, and the welding parts are evenly distributed at intervals on the same circumference with the center of the battery bottom cover as the center of the circle.

[0016] Further, each welding surface includes a straight line segment and an arc segment. The straight line segment extends radially, and the arc segment is located at one end of the straight line segment close to the center of the battery bottom cover to increase the area of each welding surface.

[0017] Further, there is one welding part, and the shape of the welding surface is a ring with the center of the battery bottom cover as the center of the circle.

[0018] Further, the battery bottom cover further includes a welding reference part provided beside the welding part for positioning the welding part. The welding reference part protrudes upward from the flat part, and the upper end surface of the welding reference part is lower than the upper end surface of the welding part.

[0019] Further, the battery bottom cover further includes a reinforcing part protruding upward from the flat part. The upper end surface of the reinforcing part is lower than or flush with the welding surface, and the lower end surface of the reinforcing part is higher than the lower plate surface of the flat part.

[0020] The technical solution of the battery housing provided by the present utility model is as follows:

[0021] A battery housing includes a battery bottom cover and a housing body adapted to the battery bottom cover. The structure of the battery bottom cover is the same as that of the battery bottom cover in the above battery bottom cover technical solution.

[0022] The technical solution of the single cell provided by the present utility model is as follows:

[0023] A single cell includes a battery housing and an electric core installed in the battery housing. The negative electrode tab or the positive electrode tab of the electric core is directly welded to the battery bottom cover of the battery housing. The structure of the battery housing is the same as that of the battery housing in the above battery housing technical solution.

[0024] The beneficial effects of the present utility model are as follows: Since the thickness of the welding part is less than that of the flat part, when welding the welding part and the negative electrode tab or the positive electrode tab from the bottom of the battery bottom cover, the welding power can be reduced, and the tab of the electrode assembly can be prevented from being welded through. At the same time, the flat part is thicker to ensure the structural strength of the battery bottom cover, and the welding part protruding upward from the flat part can also enhance the structural strength of the battery bottom cover, thereby preventing the battery bottom cover from deforming during welding and improving the welding yield and product quality of the single cell. Description of the Drawings

[0025] Figure 1 It is a schematic structural view of the battery bottom cover from an angle in the specific embodiment 1 of the single cell of the present utility model;

[0026] Figure 2This is a schematic structural diagram of the battery bottom cover of the first specific embodiment of the single battery of the present utility model from another angle;

[0027] Figure 3 This is a bottom view of the battery bottom cover of the first specific embodiment of the single battery of the present utility model;

[0028] Figure 4 For Figure 3 View taken along line B-B in

[0029] Figure 5 For Figure 4 Enlarged structural view at C in

[0030] Figure 6 This is an exploded structural view of the battery housing of the first specific embodiment of the single battery of the present utility model;

[0031] Figure 7 This is a top view of the battery housing of the first specific embodiment of the single battery of the present utility model;

[0032] Figure 8 For Figure 7 View taken along line A-A of

[0033] Figure 9 For Figure 8 Enlarged structural view at D in

[0034] Figure 10 This is a schematic structural diagram of a battery bottom cover in the second specific embodiment of the single battery of the present utility model;

[0035] Figure 11 This is another schematic structural diagram of a battery bottom cover in the second specific embodiment of the single battery of the present utility model;

[0036] Figure 12 This is yet another schematic structural diagram of a battery bottom cover in the second specific embodiment of the single battery of the present utility model;

[0037] Figure 13 This is a schematic structural diagram of the battery bottom cover in the third specific embodiment of the single battery of the present utility model.

[0038] Explanation of reference numerals:

[0039] 1. Battery bottom cover; 2. Welding part; 3. Reinforcing part; 4. Welding reference part; 5. Explosion-proof indentation; 6. Assembly step; 61. Support surface; 62. Limiting surface; 7. Housing body; 8. Weld seam; 9. Explosion-proof part. Detailed implementation manners

[0040] To solve the problems in the background art, the core inventive concept of the present utility model is as follows: The battery bottom cover is provided with a welding part that protrudes upward from the flat part, and the welding part is welded to the negative electrode tab or the positive electrode tab, so that the welding part can be thinned without thinning the flat part, that is, the structural strength of the battery bottom cover can be ensured while reducing the welding power.

[0041] The following further describes the present utility model in detail with reference to embodiments.

[0042] Specific embodiment 1 of the single cell provided by the present utility model:

[0043] Referring to Figure 1-9 As shown, the single cell includes a battery housing and an electric core installed in the battery housing. The battery housing includes a housing body 7 and a battery bottom cover 1 welded to the housing body 7. The upper end of the battery housing is open, so as to facilitate the placement of the electric core assembly into the battery housing. After that, the battery housing is hermetically connected to the battery top cover, so as to realize the sealing of the single cell; of course, in other specific embodiments, the housing body 7 and the battery bottom cover 1 can also be integrally formed.

[0044] As Figure 1-4 shown, the battery bottom cover 1 includes a flat part and at least one welding part 2 that protrudes upward from the flat part. The upper end surfaces of the welding parts 2 are all higher than the upper plate surface of the flat part and form a welding surface for welding connection with the negative electrode tab. The thickness H of each welding part 2 is less than the thickness h of the flat part. The negative electrode tab of the electric core is directly welded to the battery bottom cover 1 of the battery housing through the welding surface. Of course, according to the different materials of the battery housing, in other specific embodiments, the welding surface of the battery bottom cover 1 can be directly welded to the positive electrode tab of the electric core.

[0045] Specifically, in Figure 1-3 , there are four welding parts 2, but in other specific embodiments, referring to Figure 1-3 shown, the welding parts 2 can be 2, 3 or more in number.

[0046] In different specific embodiments, the positive terminal and the negative terminal for electrically connecting the single cell to the electrical device can both be provided on the battery top cover of the single cell; or, one of the positive terminal and the negative terminal for electrically connecting the single cell to the electrical device is provided on the battery top cover of the single cell, and the other is provided on the battery bottom cover of the single cell.

[0047] Since the thickness of the welding part 2 is less than that of the flat part, when welding and connecting the welding part 2 and the negative electrode tab from the bottom of the battery bottom cover 1, the welding power can be reduced to avoid the electrode tab of the electrode assembly being welded through. At the same time, the flat part is relatively thick to ensure the structural strength of the battery bottom cover 1, and the welding part 2 protruding upward from the flat part can also enhance the structural strength of the battery bottom cover 1, thereby avoiding deformation of the battery bottom cover 1 during welding and improving the welding yield and product quality.

[0048] To reduce costs, as a specific implementation, referring to Figure 1-3 As shown, the battery bottom cover 1 is formed by stamping a sheet metal, or the battery bottom cover 1 is formed by cold extrusion of a blank metal, or the battery bottom cover 1 is formed by cold extrusion of a blank metal followed by stamping, with relatively low costs. Of course, in other specific implementations, the battery bottom cover 1 can also be integrally injection molded.

[0049] To increase the total area of the welding surface as much as possible while ensuring the structural strength of the battery bottom cover 1 and reducing the resistance value at the connection between the negative electrode tab and the welding part 2, as a specific implementation, referring to Figure 1-3 As shown, the shape of the battery bottom cover 1 is a centrally symmetric figure. Specifically, the battery bottom cover 1 is a circular cover. There are at least two welding parts 2, and the welding parts 2 are evenly spaced on the same circumference with the center of the battery bottom cover as the center. That is, the welding parts 2 (the weak parts of the battery bottom cover 1) are evenly spaced on the same circumference, thereby ensuring the distance between adjacent welding parts 2 and avoiding the structural strength at a certain point on the battery bottom cover 1 not meeting the requirements due to the proximity of any two welding parts 2. Thus, the total area of the welding surface can be increased as much as possible while ensuring the structural strength of the battery bottom cover 1, that is, increasing the total contact area between the welding surface and the negative electrode tab, and further reducing the resistance value at the connection between the negative electrode tab and the welding part 2, improving the performance of the battery.

[0050] Specifically, referring to Figure 1-3 As shown, the welding parts 2 are arranged in pairs. The two welding parts 2 in each pair are centrally symmetrically arranged around the center of the battery bottom cover 1.

[0051] To further increase the total area of the welding surface, as a specific implementation, as Figure 1-3 shown, each welding surface includes a straight segment and an arc segment. The straight segment extends radially, and the arc segment is located at one end of the straight segment close to the center of the battery bottom cover (i.e., the center of the battery bottom cover), so as to increase the area of each welding surface, thereby increasing the total contact area between the welding surface and the negative electrode tab, and further reducing the resistance value at the connection between the negative electrode tab and the welding part 2, improving the performance of the battery.

[0052] However, in other specific implementations, referring to Figure 1-3As shown, each welding surface can also only include straight segments, and it is ensured that there is sufficient distance at the end of the welding surface close to the center of the battery bottom cover 1, so as to ensure the structural strength of the battery bottom cover 1. At this time, the total area of the welding surface is relatively small.

[0053] To improve production efficiency, as a specific implementation manner, the battery bottom cover 1 further includes a welding reference portion 4 for positioning the welding portion 2. The welding reference portion 4 protrudes upward from the flat portion, and the upper end surface of the welding reference portion 4 is lower than the upper end surface of the welding portion 2. Specifically, referring to Figure 1-2 , the number of the welding reference portions 4 is four, the number of the welding reference portions 4 is the same as the number of the welding portions 2, and the welding reference portions 4 are protrusions protruding upward from the flat portion.

[0054] On the one hand, both the welding reference portion 4 and the welding portion 2 protrude upward from the flat portion, which is convenient for processing and manufacturing the battery bottom cover 1. At the same time, the welding reference portion 4 can also play a role in strengthening the structural strength of the battery bottom cover 1; on the other hand, by photographing the position of the welding reference portion 4 with a camera, the controller can control the welding head of the laser welding device to quickly align with the welding surface, and start welding from the end of the welding surface close to the edge of the battery bottom cover 1 until the welding surface is completely welded to the negative pole tab.

[0055] Of course, in other specific implementation manners, the welding reference portion 4 may not be provided, and the welding head of the laser welding device can be quickly aligned with the welding surface manually; or, the position of the welding portion can be directly detected by a camera, and the controller can control the welding head of the laser welding device to align with the welding surface.

[0056] To avoid deformation of the battery bottom cover 1 during welding, as a specific implementation manner, as Figure 1-3 shown, the battery bottom cover 1 further includes a reinforcing portion 3 for strengthening the structural strength of the battery bottom cover 1. The reinforcing portion 3 protrudes upward from the flat portion, the upper end surface of the reinforcing portion 3 is lower than the welding surface, the lower end surface of the reinforcing portion 3 is higher than the lower plate surface of the flat portion, and the reinforcing portion 3 can further increase the structural strength of the battery bottom cover 1, avoid deformation of the battery bottom cover 1 during welding, and ensure the welding quality; at the same time, the upper end surface of the reinforcing portion 3 is lower than the welding surface, which can prevent the reinforcing portion 3 from contacting the negative pole tab, so as to better weld the negative pole tab and the welding portion 2. Of course, in other specific implementation manners, the upper end surface of the reinforcing portion 3 can also be flush with the welding surface.

[0057] At this time, the reinforcing portion 3, the welding portion 2 and the welding reference portion 4 all protrude upward from the flat portion, which is convenient for processing and manufacturing the battery bottom cover 1.

[0058] But in other specific implementation manners, referring to Figure 1-3As shown, ribs can also be provided on the upper plate surface of the flat plate portion, or ribs can be provided on the lower plate surface of the flat plate portion. Compared with the technical solution of providing ribs on the lower or upper plate surface of the flat plate portion, making the reinforcing portion 3 protrude upward from the flat plate portion can reduce the weight of the flat plate portion, thereby reducing the weight of the battery case and improving the weight energy density of the single battery.

[0059] In other specific embodiments, referring to Figure 1-3 As shown, when the battery bottom cover 1 is integrally injection molded or 3D printed, the lower end surface of the reinforcing portion 3 can also be lower than the lower plate surface of the flat plate portion. At this time, the reinforcing portion 3 protrudes downward from the flat plate portion.

[0060] To further improve the battery performance, as Figure 1-3 shown, the reinforcing portion 3 is at least two arc-shaped ribs, and the arc-shaped ribs are evenly spaced on the same circumference centered on the center of the battery bottom cover, and one end of each welding portion 2 and each arc-shaped rib are arranged alternately on the same circumference.

[0061] Specifically, as Figure 1-3 shown, the reinforcing portion 3 is at least a pair of arc-shaped ribs evenly spaced on the same circumference, and each pair of arc-shaped ribs is centrosymmetrically arranged with the center of the battery bottom cover 1 as the symmetry center. One end of the welding portion extends into the space between two adjacent arc-shaped ribs to utilize the space between adjacent welding portions to increase the total area of the welding surface and improve the battery performance.

[0062] However, in other embodiments, referring to Figure 1-3 shown, the reinforcing portion 3 can also be only one annular rib, or the reinforcing portion 3 is two, three or other numbers of arc-shaped, rectangular or other shaped ribs. In this embodiment, the setting form of the reinforcing portion 3 is not limited as long as the reinforcing portion 3 can strengthen the structural strength of the battery bottom cover 1.

[0063] However, in other specific embodiments, the reinforcing portion 3 can be not provided, but the structural strength of the battery bottom cover 1 can be improved by increasing the thickness of the flat plate portion to prevent the battery bottom cover 1 from deforming during welding.

[0064] To ensure safety, as a specific embodiment, as Figure 1-5 shown in FIGS. 7-9, explosion-proof indentations 5 are provided on the flat plate portion. The shape of the explosion-proof indentations 5 is at least 2 / 3 of a circle, and all welding surfaces are located inside the circle where the explosion-proof indentations 5 are located. When the internal pressure of the battery is too high, the explosion-proof indentations 5 are opened, thereby releasing the internal pressure of the battery to the outside. To ensure the total area of the welding surface, the diameter of the explosion-proof indentations 5 is greater than 2 / 3 of the diameter of the battery bottom cover 1.

[0065] Specifically, as Figure 1-5As shown, the explosion-proof indentation 5 is a complete circle. However, in other specific embodiments, the explosion-proof indentation 5 can also be 2 / 3 of a circle or 3 / 4 of a circle. In this embodiment, no specific shape of the explosion-proof indentation 5 is restricted, as long as the explosion-proof indentation 5 can function properly for explosion protection.

[0066] In other specific embodiments, the explosion-proof indentation 5 may not be provided on the battery bottom cover 1, but an explosion-proof valve may be provided on the battery top cover; or, an explosion-proof valve is provided on the battery top cover and an explosion-proof indentation 5 is provided on the battery bottom cover 1. At this time, the explosion-proof indentation 5 is used as a secondary explosion-proof device.

[0067] To further ensure safety, as a specific embodiment, as Figure 1-2 shown, an explosion-proof portion 9 is provided at the center of the battery bottom cover 1. When the battery bottom cover 1 is a circular cover, the explosion-proof portion 9 is provided at the center of the circle of the battery bottom cover. The explosion-proof portion 9 can specifically be a weak portion with a relatively thin thickness, or an explosion-proof indentation is provided in a circle at the edge of the explosion-proof portion 9. When the internal pressure of the single battery is relatively large, the explosion-proof portion 9 is damaged, so that the pressure inside the single battery leaks to the outside of the single battery. When the pressure inside the single battery is relatively large, the winding core (i.e., the wound battery core) will first deform from the outer periphery, and the middle part of the winding core deforms last. Since the explosion-proof portion 9 is provided at the center of the battery bottom cover 1, the explosion-proof portion 9 is opposite to the middle part of the winding core. When the winding core just starts to deform, the explosion-proof portion 9 will not be blocked by the deformed winding core, and the explosion-proof performance is good.

[0068] To improve the welding yield, as a specific embodiment, as Figure 5-9 shown, an assembly step 6 for limiting the position of the housing body 7 is provided on the battery bottom cover 1. The assembly step 6 includes a support surface 61 for supporting the housing body 7 and a limiting surface 62 for limiting and cooperating with the inner wall surface of the housing body 7. The position of the housing body 7 is restricted by using the limiting surface 62 and the support surface 61, and the relative position of the housing body 7 and the battery bottom cover 1 during welding is fixed, so that a weld seam 8 is formed between the housing body 7 and the area corresponding to the support surface 61 on the battery bottom cover 1, improving the welding yield.

[0069] However, in other specific embodiments, as shown in reference to Figure 5-9 shown, a stop step may also be provided on the housing body 7, so that the outer wall surface of the battery bottom cover 1 is in limiting cooperation with the inner surface of the housing body 7, and the stop step is in stop cooperation with the upper surface of the battery bottom cover 1, thereby restricting the relative movement between the housing body 7 and the battery bottom cover 1 during welding.

[0070] Specific embodiment 2 of the single battery provided by the present utility model:

[0071] The purpose of this embodiment is to provide a single cell with a different battery housing structure. The main difference between this embodiment and the specific embodiment 1 is that in specific embodiment 1, the single cell is a cylindrical battery, while in this embodiment, similar to the regular polygonal prism-shaped battery in the authorized publication number CN217134494U, the single cell in this embodiment is a regular polygonal prism-shaped battery.

[0072] The battery bottom cover 1 is a regular polygon cover, and there are at least two welding parts, and each welding part is evenly distributed at intervals on the same circumference centered on the center of the battery bottom cover, so as to ensure the distance between adjacent welding parts 2 and avoid the structural strength of a certain point on the battery bottom cover 1 not meeting the requirements due to the proximity of any two welding parts 2. Thus, while ensuring the structural strength of the battery bottom cover 1, the total area of the welding surface can be increased as much as possible, that is, the total contact area between the welding surface and the negative electrode tab is increased, and further the resistance value at the connection between the negative electrode tab and the welding part 2 is reduced, improving the performance of the battery. Specifically, the shape of the battery bottom cover can be an equilateral triangle, a square, a regular pentagon, a regular hexagon, etc.

[0073] Preferably, in some specific embodiments, the shape of the battery bottom cover is a centrally symmetric figure, and the center of the battery bottom cover is the symmetric center of the battery bottom cover. For example, the shape of the battery bottom cover is a regular hexagon, a regular octagon, etc.

[0074] Specific embodiment 3 of the single cell provided by the present utility model:

[0075] The purpose of this embodiment is to provide a single cell with only one welding part. The main difference between this embodiment and the specific embodiment 1 is that in specific embodiment 1, there are at least two welding parts, while in this embodiment, there is only one welding part.

[0076] There is only one welding part. In different specific embodiments, as Figure 10 shown, the shape of the welding surface of the welding part 2 can be a ring centered on the center of the battery bottom cover; or, as Figure 11 shown, the shape of the welding surface of the welding part 2 is a circle; or, as Figure 12 shown, the shape of the welding surface of the welding part 2 is an ellipse. In this embodiment, the shape of the welding surface is not restricted as long as there is only one welding surface.

[0077] Specific embodiment 4 of the single cell provided by the present utility model:

[0078] The purpose of this embodiment is to provide a single cell with a different welding part structure. The main difference between this embodiment and the specific embodiment 1 is that in specific embodiment 1, the welding parts are evenly distributed at intervals on the same circumference, while in this embodiment, the welding parts are arranged arbitrarily on the battery bottom cover 1.

[0079] The welding part 2 may not be arranged in central symmetry either. For example, as Figure 13 shown, the welding part 2 only includes a circular welding surface and a rectangular welding surface. In this case, it is necessary to ensure the distance between adjacent welding parts 2.

[0080] Specific embodiments of the battery bottom cover provided by the present utility model:

[0081] The specific structure of the battery bottom cover in this embodiment is the same as that of the battery bottom cover in the specific embodiment of the single battery of the present utility model, and will not be described in detail here.

[0082] Specific embodiments of the battery housing provided by the present utility model:

[0083] The battery housing includes a battery bottom cover and a housing body adapted to the battery bottom cover. The specific structure of the battery housing in this embodiment is the same as that of the battery housing in the specific embodiment of the single battery of the present utility model, and will not be described in detail here.

[0084] Finally, it should be noted that the above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make modifications to the technical solutions described in the foregoing embodiments without creative efforts, or make equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A battery bottom cover, characterized in that, It includes a flat plate portion and at least one welding portion protruding upward from the flat plate portion. The upper end surfaces of the welding portions are all higher than the upper plate surface of the flat plate portion and form welding surfaces for welding connection with a negative electrode tab or a positive electrode tab. The thickness of each welding portion is less than the thickness of the flat plate portion.

2. The battery bottom cover according to claim 1, characterized in that, The battery bottom cover is a circular cover.

3. The battery bottom cover according to claim 1, wherein, The battery bottom cover is a regular polygon cover.

4. The battery bottom cover according to claim 2, characterized in that, There are at least two welding portions, and the welding portions are evenly spaced on the same circumference centered on the center of the battery bottom cover.

5. The battery bottom cover according to claim 4, wherein Each welding surface includes a straight line segment and an arc segment. The straight line segment extends radially, and the arc segment is located at one end of the straight line segment close to the center of the battery bottom cover to increase the area of each welding surface.

6. The battery bottom cover according to claim 4, characterized in that, There is one welding portion, and the shape of the welding surface is a ring centered on the center of the battery bottom cover.

7. The battery bottom cover according to any one of claims 1-6, characterized in that, The battery bottom cover further includes a welding reference portion provided beside the welding portion for positioning the welding portion. The welding reference portion protrudes upward from the flat plate portion, and the upper end surface of the welding reference portion is lower than the upper end surface of the welding portion.

8. The battery bottom cover according to any one of claims 1-6, characterized in that, The battery bottom cover further includes a reinforcing portion protruding upward from the flat plate portion. The upper end surface of the reinforcing portion is lower than or flush with the welding surface, and the lower end surface of the reinforcing portion is higher than the lower plate surface of the flat plate portion.

9. A battery housing, comprising a battery bottom cover and a housing body adapted to the battery bottom cover, characterized in that, The battery bottom cover is the battery bottom cover described in any one of claims 1-8.

10. A single cell includes a battery housing and an electric core installed in the battery housing. The negative electrode tab or the positive electrode tab of the electric core is directly welded to the battery bottom cover of the battery housing. It is characterized in that, The battery housing is the battery housing described in claim 9.

Images