Battery and shell and shell bottom cover thereof

Abstract

The utility model relates to a battery and a shell and a shell bottom cover thereof. The battery shell bottom cover comprises a flat plate part and a plurality of welding parts upwards protruding out of the flat plate part, the upper end face of each welding part is higher than the upper end face of the flat plate part to form a welding face used for being welded to the negative electrode lug or the positive electrode lug, and the welding parts are in a strip shape and extend from the edge position of the shell bottom cover to the center position. According to the utility model, the welding part is arranged on the bottom cover of the battery shell, and the positive pole lug or the negative pole lug of the battery cell is directly welded and fixed with the welding part, so that a confluence plate is omitted, and the cost is reduced. According to the technical scheme, only one-time welding is needed, two-time welding (the positive pole lug or the negative pole lug of the battery cell is welded with the confluence plate, and the confluence plate is welded with the bottom cover) is not needed, the welding process is simplified, the risk of low yield caused by two-time welding is reduced, and the product yield can be improved. And the welding part is arc-shaped, so that the welding area is increased, and the welding quality is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of batteries, and particularly relates to a battery and a shell and a bottom cover of the shell. Background Art

[0002] Batteries are widely used in various products such as digital cameras, computers, mobile phones, etc. In the prior art, batteries generally include a battery shell, a battery top cover, a battery cell, a negative electrode collector plate, and a positive electrode collector plate. The battery shell includes a bottom cover and a shell body. The battery cell, the negative electrode collector plate, and the positive electrode collector plate are arranged in the battery shell. The negative electrode tab of the battery cell is welded to the negative electrode collector plate (or negative electrode adapter), and the positive electrode tab of the battery cell is welded to the positive electrode collector plate (or positive electrode adapter). When the material of the battery shell is different, the bottom cover is welded to different collector plates. For example, when the battery shell is an aluminum shell, the bottom cover is welded to the positive electrode collector plate (for example, the battery in the Chinese utility model patent with the authorization announcement number CN220856711U and the authorization announcement date of 2024.04.26); when the battery shell is a steel shell, the bottom cover is welded to the negative electrode collector plate.

[0003] The battery shell can be a shell, such as the battery in the Chinese utility model patent with the authorization announcement number CN220856711U, in which the bottom cover is a circular cover; the battery shell can also be a regular polygonal shell, such as the regular polygonal battery disclosed in the Chinese utility model patent with the authorization announcement number CN217134494U and the authorization announcement date 2022.08.05. In the regular polygonal battery, the bottom cover is a regular polygonal cover, and the negative pole ear of the battery cell is directly drawn out from the top of the battery cell and connected to the negative terminal, and the positive pole ear of the battery cell is drawn out from the bottom of the battery cell and connected to the positive terminal through the battery shell, and the positive terminal and the negative terminal are used to connect to the electrical equipment. Because when the bottom cover and the corresponding pole ear are conductively connected, it is necessary to first weld the corresponding pole ear to the corresponding collector plate, and then weld the corresponding collector plate to the bottom cover, a total of two welding operations are required, the process is cumbersome, and the manufacturing cost is high. Utility Model Content

[0004] The utility model aims to provide a battery and its shell and shell bottom cover. The utility model provides a welding part on the shell bottom cover, and the pole ear is directly connected to the welding part, thereby saving the bottom busbar, simplifying the welding process, and reducing the manufacturing cost of the battery monomer.

[0005] In order to achieve the above-mentioned purpose, the technical solution of the housing bottom cover of the battery cell provided by the utility model is:

[0006] A battery case bottom cover includes a flat plate portion and a plurality of welding portions that protrude upward from the flat plate portion. The upper end surfaces of the welding portions are all higher than the upper end surface of the flat plate portion, forming welding surfaces for welding with the negative electrode tab or the positive electrode tab. The welding portions are strip-shaped and extend from the edge position of the case bottom cover towards the center position.

[0007] Furthermore, the welding portions are straight strip-shaped, extend along the radial direction of the case bottom cover, and the plurality of welding portions are evenly spaced along the circumferential direction of the case bottom cover.

[0008] Furthermore, the welding portions are curved strip-shaped. The welding portion includes a straight line segment and an arc segment. The straight line segment extends along the radial direction of the case bottom cover, and the arc segment is located at one end of the straight line segment close to the center of the case bottom cover. The plurality of welding portions are evenly spaced along the circumferential direction of the case bottom cover.

[0009] Furthermore, the arc segments of the plurality of welding portions all extend in the counterclockwise or clockwise direction.

[0010] Furthermore, the case bottom cover includes a reinforcing portion that protrudes upward from the flat plate portion. The upper end surface of the reinforcing portion is lower than or flush with the welding portion, and the lower end surface of the reinforcing portion is higher than the lower plate surface of the flat plate portion.

[0011] Furthermore, the reinforcing portion is arc-shaped. Each reinforcing rib is located on the same circumference with the center of the bottom of the case as the center of the circle. The number of the reinforcing portions is equal to the number of the welding portions, and the reinforcing portions and the welding portions are arranged alternately.

[0012] Furthermore, the case bottom cover 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.

[0013] The technical solution of the battery case provided by the present utility model is:

[0014] A battery case includes a main body and a case bottom cover located at the bottom of the main body. The case bottom cover is the case bottom cover in the technical solution of the above battery case bottom cover.

[0015] Furthermore, the main body and the case bottom cover are of an integral structure, and are formed by stamping from a sheet structure, or by cold extrusion processing of a blank metal, or by stamping after cold extrusion of a blank metal.

[0016] The technical solution of the battery provided by the present utility model is:

[0017] A battery cell includes a case and an electric core installed in the battery case. The case is the case in the technical solution of the above battery case, and the positive electrode tab or the negative electrode tab of the electric core is directly welded and fixed to the welding portion.

[0018] The present utility model provides a battery, its housing, and the bottom cover of the housing. Compared with the prior art, the beneficial effects are as follows:

[0019] By providing a welding portion on the bottom cover of the battery housing, the positive electrode tab or the negative electrode tab of the battery cell is directly welded and fixed to the welding portion, eliminating the need for a bus bar, thereby reducing costs. Only one welding is required, without the need for two weldings (welding the positive electrode tab or the negative electrode tab of the battery cell to the bus bar and then welding the bus bar to the bottom cover), simplifying the welding process and reducing the risk of low yield caused by two weldings, which helps to improve the product yield. The welding portion is arc-shaped, which helps to increase the welding area and improve the welding quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural view of the bottom cover of the battery according to the first specific embodiment of the present utility model from an angle;

[0021] Figure 2 It is a schematic structural view of the bottom cover of the battery according to the first specific embodiment of the present utility model from another angle;

[0022] Figure 3 It is a bottom view of the bottom cover of the battery according to the first specific embodiment of the present utility model;

[0023] Figure 4 It is Figure 3 the view taken along the line B-B in

[0024] Figure 5 It is Figure 4 the enlarged view of the structure at C in

[0025] Figure 6 It is an exploded view of the structure of the battery housing according to the first specific embodiment of the present utility model;

[0026] Figure 7 It is a top view of the battery housing according to the first specific embodiment of the present utility model;

[0027] Figure 8 It is Figure 7 the view taken along the line A-A in

[0028] Figure 9 It is Figure 8 the enlarged view of the structure at D in

[0029] Figure 10 It is a schematic structural view of a bottom cover in the second specific embodiment of the battery according to the present utility model;

[0030] Figure 11 It is a schematic structural view of a bottom cover in the third specific embodiment of the battery according to the present utility model;

[0031] Figure 12This is a schematic structural diagram of the battery housing of the present utility model;

[0032] Explanation of reference numerals:

[0033] 1. Bottom cover; 2. Welding part; 3. Reinforcing part; 4. Welding reference part; 5. Explosion-proof notch; 6. Assembly step; 61. Support surface; 62. Limiting surface; 7. Housing body; 8. Weld seam; 9. Explosion-proof part. Detailed implementation manners

[0034] Specific embodiment 1 of the battery provided by the present utility model:

[0035] Refer to Figure 1-9 As shown, the battery includes a battery housing and an electric core installed in the battery housing. The battery housing includes a housing body 7 and a bottom cover 1 welded to the housing body 7. The upper end of the battery housing is open, so as to facilitate putting the electric core assembly into the battery housing. Then, the battery housing is hermetically connected to the battery top cover, thereby realizing the sealing of the battery; of course, in other specific implementation manners, the housing body 7 and the bottom cover 1 can also be integrally formed.

[0036] As Figure 1-4 shown, the bottom cover 1 includes a flat plate portion and at least one welding part 2 protruding upward from the flat plate portion. The upper end surfaces of the welding parts 2 are all higher than the upper plate surface of the flat plate portion and form welding surfaces 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 plate portion. The negative electrode tab of the electric core is directly welded to the bottom cover 1 of the battery housing through the welding surface. Of course, according to different materials of the battery housing, in other specific implementation manners, the welding surface of the bottom cover 1 can be directly welded to the positive electrode tab of the electric core.

[0037] Specifically, in Figure 1-3 it, there are four welding parts 2, but in other specific implementation manners, refer to Figure 1-3 shown, the welding parts 2 can be 2, 3 or more in number.

[0038] In different specific implementation manners, the positive terminal and the negative terminal for electrically connecting the battery to the electrical equipment can both be provided on the battery top cover of the battery; or, one of the positive terminal and the negative terminal for electrically connecting the battery to the electrical equipment is provided on the battery top cover of the battery, and the other is provided on the bottom cover of the battery.

[0039] Since the thickness of the welding part 2 is less than the thickness of the flat plate portion, when welding the welding part 2 and the negative electrode tab from the bottom of the bottom cover 1, the welding power can be reduced, and the electrode tab of the electrode assembly can be prevented from being welded through; at the same time, the flat plate portion is thicker to ensure the structural strength of the bottom cover 1, and the welding part 2 protruding upward from the flat plate portion can also enhance the structural strength of the bottom cover 1, thereby preventing the bottom cover 1 from deforming during welding and improving the welding yield and product quality.

[0040] In order to reduce costs, as a specific implementation, referring to Figure 1-3 as shown, the bottom cover 1 is formed by stamping sheet metal, or the bottom cover 1 is formed by cold extrusion of blank metal, or the bottom cover 1 is formed by cold extrusion of blank metal followed by stamping, with relatively low costs. Of course, in other specific implementations, the bottom cover 1 can also be integrally injection molded.

[0041] In order to maximize the total area of the welding surface while ensuring the structural strength of the 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 bottom cover 1 is a centrally symmetric figure. Specifically, the 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 centered on the center of the bottom cover. That is, the welding parts 2 (the weak parts of the bottom cover 1) are evenly spaced on the same circumference, so as to ensure the distance between adjacent welding parts 2 and prevent the distance between any two welding parts 2 from being too close, resulting in the structural strength at a certain point on the bottom cover 1 not meeting the requirements. Thus, while ensuring the structural strength of the bottom cover 1, the total area of the welding surface can be maximized, that is, the total contact area between the welding surface and the negative electrode tab is increased, thereby reducing the resistance value at the connection between the negative electrode tab and the welding part 2 and improving the performance of the battery.

[0042] 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 bottom cover 1.

[0043] In order 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 bottom cover (i.e., the center of the 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 and improving the performance of the battery.

[0044] However, in other specific implementations, referring to Figure 1-3 as shown, each welding surface can also only include a straight segment, and ensure that there is enough distance at the end of the welding surface close to the center of the bottom cover 1, so as to ensure the structural strength of the bottom cover 1. At this time, the total area of the welding surface is relatively small.

[0045] In order to improve production efficiency, as a specific implementation, the bottom cover 1 further includes a welding reference part 4 for positioning the welding part 2. The welding reference part 4 protrudes upward from the flat part, and the upper end surface of the welding reference part 4 is lower than the upper end surface of the welding part 2. Specifically, referring to Figure 1-2, the number of the welding reference parts 4 is four, which is the same as the number of the welding parts 2, and the welding reference parts 4 are protrusions protruding upward from the flat plate part.

[0046] On the one hand, both the welding reference parts 4 and the welding parts 2 protrude upward from the flat plate part, which is convenient for processing and manufacturing the bottom cover 1. At the same time, the welding reference parts 4 can also play a role in strengthening the structural strength of the bottom cover 1. On the other hand, by photographing the positions of the welding reference parts 4 with a camera, the controller can control the welding head of the laser welding equipment to quickly align with the welding surface, and start welding from one end of the welding surface close to the edge of the bottom cover 1 until the welding surface is completely welded to the negative electrode tab.

[0047] Of course, in other specific embodiments, the welding reference parts 4 may not be provided, and the welding head of the laser welding equipment can be quickly aligned with the welding surface manually; or, the positions of the welding parts can be directly detected by a camera, and the controller can control the welding head of the laser welding equipment to align with the welding surface.

[0048] In order to avoid deformation of the bottom cover 1 during welding, as a specific embodiment, as Figure 1-3 shown, the bottom cover 1 further includes a reinforcing part 3 for strengthening the structural strength of the bottom cover 1. The reinforcing part 3 protrudes upward from the flat plate part. The upper end surface of the reinforcing part 3 is lower than the welding surface, and the lower end surface of the reinforcing part 3 is higher than the lower plate surface of the flat plate part. The reinforcing part 3 can further increase the structural strength of the bottom cover 1, avoid deformation of the bottom cover 1 during welding, and ensure the welding quality. At the same time, the upper end surface of the reinforcing part 3 is lower than the welding surface, which can prevent the reinforcing part 3 from contacting the negative electrode tab, so as to better weld the negative electrode tab and the welding part 2. Of course, in other specific embodiments, the upper end surface of the reinforcing part 3 can also be flush with the welding surface.

[0049] At this time, the reinforcing part 3, the welding part 2 and the welding reference part 4 all protrude upward from the flat plate part, which is convenient for processing and manufacturing the bottom cover 1.

[0050] But in other specific embodiments, referring to Figure 1-3 shown, reinforcing ribs can also be provided on the upper plate surface of the flat plate part, or on the lower plate surface of the flat plate part. Compared with the technical solutions of providing reinforcing ribs on the lower or upper plate surface of the flat plate part, making the reinforcing part 3 protrude upward from the flat plate part can reduce the weight of the flat plate part, thereby reducing the weight of the battery housing and improving the weight energy density of the battery.

[0051] In other specific embodiments, referring to Figure 1-3 shown, when the bottom cover 1 is integrally injection molded or 3D printed, the lower end surface of the reinforcing part 3 can also be lower than the lower plate surface of the flat plate part. At this time, the reinforcing part 3 protrudes downward from the flat plate part.

[0052] In order to further improve the battery performance, as Figure 1-3As shown, the strengthening part 3 is at least two arc-shaped reinforcing ribs, and each arc-shaped reinforcing rib is evenly distributed at intervals on the same circumference with the center of the bottom cover as the center of the circle. One end of each welding part 2 and each arc-shaped reinforcing rib are arranged alternately on the same circumference.

[0053] Specifically, as Figure 1-3 shown, the strengthening part 3 is at least a pair of arc-shaped reinforcing ribs evenly distributed at intervals on the same circumference. Each pair of arc-shaped reinforcing ribs is centrally symmetrically arranged with the center of the bottom cover 1 as the center of symmetry. One end of the welding part extends between two adjacent arc-shaped reinforcing ribs to utilize the space between adjacent welding parts to increase the total area of the welding surface and improve the battery performance.

[0054] However, in other embodiments, referring to Figure 1-3 shown, the strengthening part 3 can also be only one annular reinforcing rib, or the strengthening part 3 is two, three or other numbers of arc-shaped, rectangular or other shaped reinforcing ribs. In this embodiment, the setting form of the strengthening part 3 is not limited as long as the strengthening part 3 can strengthen the structural strength of the bottom cover 1.

[0055] However, in other specific embodiments, the strengthening part 3 can be not provided, but the structural strength of the bottom cover 1 can be improved by increasing the thickness of the flat part to prevent the bottom cover 1 from deforming during welding.

[0056] To ensure safety, as a specific embodiment, as Figure 1-5 shown in FIGS. 7-9, an explosion-proof notch 5 is provided on the flat part. The shape of the explosion-proof notch 5 is at least 2 / 3 of a circle, and all welding surfaces are located inside the circle where the explosion-proof notch 5 is located. When the internal pressure of the battery is too high, the explosion-proof notch 5 is opened, so as to release the internal pressure of the battery to the outside. To ensure the total area of the welding surface, the diameter of the explosion-proof notch 5 is greater than 2 / 3 of the diameter of the bottom cover 1.

[0057] Specifically, as Figure 1-5 shown, the explosion-proof notch 5 is a complete circle, but in other specific embodiments, the explosion-proof notch 5 can also be 2 / 3 of a circle or 3 / 4 of a circle. In this embodiment, the specific shape of the explosion-proof notch 5 is not limited as long as the explosion-proof notch 5 can play the explosion-proof role normally.

[0058] In other specific embodiments, the explosion-proof notch 5 can also not be provided on the bottom cover 1, but an explosion-proof valve can be provided on the battery top cover; or, an explosion-proof valve is provided on the battery top cover, and an explosion-proof notch 5 is provided on the bottom cover 1. At this time, the explosion-proof notch 5 is used as a secondary explosion-proof device.

[0059] To further ensure safety, as a specific embodiment, as Figure 1-2As shown in the figure, an explosion-proof part 9 is provided at the center of the bottom cover 1. When the bottom cover 1 is a circular cover, the explosion-proof part 9 is arranged at the center of the circle of the bottom cover. The explosion-proof part 9 can specifically be a thin and weak part, or a circle of explosion-proof notches is provided at the edge of the explosion-proof part 9. When the internal pressure of the battery is relatively high, the explosion-proof part 9 is damaged, so that the internal pressure of the battery leaks to the outside of the battery. When the pressure inside the battery is relatively high, the wound core (i.e., the wound type battery cell) will first deform from the outer periphery, and the middle part of the wound core will deform last. Since the explosion-proof part 9 is arranged at the center of the bottom cover 1, the explosion-proof part 9 is directly opposite to the middle part of the wound core. When the wound core just starts to deform, the explosion-proof part 9 will not be blocked by the deformed wound core, and the explosion-proof performance is relatively good.

[0060] In order to improve the welding yield, as a specific implementation manner, as Figure 5-9 shown in the figure, an assembly step 6 for limiting the housing body 7 is provided on the 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 limited by the limiting surface 62 and the support surface 61, and the relative position of the housing body 7 and the bottom cover 1 during welding is fixed, so that a weld 8 is formed between the areas corresponding to the support surface 61 on the housing body 7 and the bottom cover 1, and the welding yield is improved.

[0061] However, in other specific implementation manners, referring to Figure 5-9 shown in the figure, a stop step can also be provided on the housing body 7, so that the outer wall surface of the bottom cover 1 is limited and cooperated with the inner surface of the housing body 7, and the stop step is stop-cooperated with the upper surface of the bottom cover 1, so as to limit the relative movement between the housing body 7 and the bottom cover 1 during welding.

[0062] Specific embodiment 2 of the battery provided by the present utility model:

[0063] The purpose of this embodiment is to provide a battery with a different housing structure. The main difference between this embodiment and specific embodiment 1 is that: in specific embodiment 1, there are four welding parts. In this embodiment, there are three welding parts 2, and the four welding parts are evenly arranged circumferentially along the center of the housing structure.

[0064] Specific embodiment 3 of the battery provided by the present utility model:

[0065] The purpose of this embodiment is to provide a battery cell with a different battery housing structure. The main difference between this embodiment and specific embodiment 1 is that: in specific embodiment 1, the welding part is in a curved strip shape. In this embodiment, the welding part 2 is in a straight strip shape, there are four welding parts 2, the four welding parts are evenly arranged circumferentially along the center of the housing structure, and all four welding parts 2 extend radially along the bottom structure of the housing.

[0066] Specific embodiment of the battery housing provided by the present utility model:

[0067] As Figure 11 shown, the battery housing includes a bottom cover and a body adapted to the bottom cover. The specific structure of the bottom cover of the housing in this embodiment is the same as the specific structure of the housing in the specific embodiment of the present utility model, and will not be described in detail here.

[0068] Specific embodiments of the bottom cover of the battery housing provided by the present utility model:

[0069] The specific structure of the bottom cover of the battery housing in this embodiment is the same as the specific structure of the bottom cover in the specific embodiment of the battery of the present utility model, and will not be described in detail here.

[0070] 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, for those skilled in the art, they can still make modifications to the technical solutions recorded in the foregoing embodiments without creative efforts, or perform 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 within the protection scope of the present utility model.

Claims

1. A battery case bottom cover, characterized in that, It includes a flat plate portion and several welding portions protruding upward from the flat plate portion. The upper end surfaces of the welding portions are all higher than the upper end surface of the flat plate portion, forming welding surfaces for welding with the negative electrode tab or the positive electrode tab. The welding portions are strip-shaped and extend from the edge position of the bottom cover of the housing towards the central position.

2. The battery case bottom cover according to claim 1, characterized in that, The welding portions are straight strip-shaped, extend along the radial direction of the bottom cover of the housing, and several welding portions are arranged at equal intervals circumferentially along the bottom cover of the housing.

3. The battery case bottom cover according to claim 1, characterized in that, The welding portions are curved strip-shaped. The welding portions include a straight line segment and an arc segment. The straight line segment extends along the radial direction of the bottom cover of the housing, and the arc segment is located at one end of the straight line segment close to the center of the bottom cover of the housing. Several welding portions are arranged at equal intervals circumferentially along the bottom cover of the housing.

4. The battery case bottom cover according to claim 3, characterized in that, The arc segments of several welding portions all extend in the counterclockwise or clockwise direction.

5. The battery case bottom cover according to any one of claims 1 to 4, characterized in that The bottom cover of the housing 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 portion, and the lower end surface of the reinforcing portion is higher than the lower plate surface of the flat plate portion.

6. The battery case bottom cover according to claim 5, wherein, The reinforcing portion is arc-shaped, and each reinforcing rib is located on the same circumference with the center of the bottom of the housing as the center of the circle. The number of the reinforcing portions is equal to the number of the welding portions, and the reinforcing portions and the welding portions are arranged alternately.

7. The battery case bottom cover according to any one of claims 1 to 4, characterized in that The bottom cover of the housing 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. A battery housing, comprising a body and a housing bottom cover located at the bottom of the body, characterized in that, The bottom cover of the housing is the bottom cover of the housing according to any one of claims 1 to 7.

9. The battery housing according to claim 8, wherein, The body is an integral structure with the bottom cover of the housing, and is formed by stamping a sheet structure, or by cold extrusion processing of a blank metal, or by stamping after cold extrusion of a blank metal.

10. A battery, comprising a housing and an electric core installed in the battery housing, characterized in that, The housing is the housing according to claim 8 or 9, and the positive electrode tab or the negative electrode tab of the battery cell is directly welded and fixed to the welding portion.

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