Battery bottom cover with pressure relief structure, battery shell and single battery

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a battery bottom cover with a pressure relief structure, a battery shell and a single battery, the battery bottom cover with the pressure relief structure comprises a flat plate part and an anti-explosion nick arranged on the flat plate part, and the flat plate part is locally thinned to form a welding part welded with a negative pole lug or a positive pole lug of a battery cell; according to the utility model, the welding part is formed by locally thinning the battery bottom cover, so that the battery bottom cover can be directly welded with the negative pole lug or the positive pole lug of the battery cell by the welding part in a penetration welding manner, the welding power can be reduced, the welding penetration phenomenon is prevented, the product yield is improved, and the pole lugs are directly connected with the welding part, so that the production cost is reduced. The explosion-proof and pressure-relief battery has the advantages that the battery manufacturing cost is reduced, the explosion-proof nick is arranged on the battery bottom cover, the production process is simplified, a pressure-relief passage can be formed in the battery shell, other substances in the battery shell can be quickly discharged, the phenomenon that the battery monomer explodes is prevented, and the explosion-proof and pressure-relief stability of the battery is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of batteries, and particularly relates to a battery bottom cover, a battery housing and a single battery with a pressure relief structure. 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 bottom structure 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 adapter plate), and the positive electrode tab of the battery cell is welded to the positive current collector plate (or positive adapter plate). When the materials of the battery housing are different, the bottom structure is welded to different current collector plates. For example, when the battery housing is an aluminum shell, the bottom structure is welded to the positive current collector plate (such as the cylindrical battery in the Chinese utility model patent with the authorization announcement number CN220856711U and the authorization announcement date of April 26, 2024); when the battery housing is a steel shell, the bottom structure is welded to the negative current collector plate; since when electrically connecting the bottom structure and the corresponding electrode tab, it is necessary to first weld the corresponding electrode tab to the corresponding current collector plate and then weld the corresponding current collector plate to the bottom structure, a total of two weldings are required, so the welding yield of the battery is relatively low.

[0003] In addition, since the battery has a high chemical energy, once a short circuit occurs inside the battery, the pressure of the gas inside the battery housing will rise sharply in a short time. If the explosion-proof valve is not opened or becomes blocked after opening, the gas will be accumulated inside the battery housing. When the pressure inside the battery housing is too high, there is a risk of battery explosion. When the battery explodes, the housing of the single battery will be broken through, and the corrosive electrolyte inside the battery will spray outwards, which will not only corrode other parts but also trigger a chain thermal runaway of the battery pack. Therefore, when the air pressure inside the battery housing is too high and needs to be discharged, an unblocked exhaust and pressure relief channel needs to be provided to prevent the explosion of the battery single body. Content of the Utility Model

[0004] The purpose of the present utility model is to provide a battery bottom cover, a battery housing and a single cell with a pressure relief structure. By thinning a part of the battery bottom cover to form a welding part, the welding part can directly weld the battery bottom cover to the negative or positive ear of the battery cell by penetration welding, which can reduce the welding power, prevent the phenomenon of welding through, improve the product yield, and the ear is directly connected to the welding part, saving the bottom bus bar and reducing the battery manufacturing cost. An explosion-proof notch is provided on the battery bottom cover, which can not only omit the production processes such as explosion-proof sheet welding and detection, simplify the production process, but also form a pressure relief path inside the battery housing to quickly discharge the gas inside the battery housing, prevent the explosion of the single cell, and improve the explosion-proof and pressure relief stability of the battery.

[0005] To achieve the above object, the technical solution of the battery bottom cover provided by the present utility model is:

[0006] A battery bottom cover with a pressure relief structure, including a flat plate part and an explosion-proof notch provided on the flat plate part, and a part of the flat plate part is thinned to form a welding part for welding with the negative or positive ear of the battery cell.

[0007] Further, there is at least one explosion-proof notch, and the area surrounded by at least one explosion-proof notch covers or partially covers the center hole position of the end face of the battery cell.

[0008] Further, the explosion-proof notch is circular, superior arc-shaped, regular or irregular polygon.

[0009] Further, the cross-sectional shape of the explosion-proof notch is at least one of trapezoidal, triangular, semi-circular or square.

[0010] Further, there is at least one explosion-proof notch, and the area surrounded by the explosion-proof notch has no intersection with the center hole position of the end face of the battery cell.

[0011] The technical solution of the battery housing provided by the present utility model is:

[0012] A battery housing, including a body and a battery bottom cover with a pressure relief structure located at the bottom of the body, and the battery bottom cover with a pressure relief structure is the battery bottom cover with a pressure relief structure in the above technical solution.

[0013] The technical solution of the single cell provided by the present utility model is:

[0014] A single cell, including a housing and a battery cell installed in the battery housing, the negative or positive ear of the battery cell is directly welded to the battery bottom cover of the battery housing, the housing is the housing in the above technical solution, and further includes a top cover, the top cover is hermetically connected to the top of the housing, and an explosion-proof valve is provided on the top cover.

[0015] The beneficial effects of the present utility model are as follows:

[0016] Since the thickness of the welded part after being thinned is less than that of the flat part, when welding and connecting the welded part with the negative electrode tab or the positive electrode tab from the bottom of the bottom structure, 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 part is relatively thick to ensure the structural strength of the bottom structure, and the fact that the welded part protrudes upward from the flat part can also enhance the structural strength of the bottom structure, thereby preventing the bottom structure from deforming during welding and improving the welding yield and product quality; the present utility model is provided with an explosion-proof notch on the battery bottom cover. When the internal pressure of the battery cell is relatively large, the explosion-proof notch is damaged, so that the pressure inside the battery cell leaks to the outside of the battery cell. When the pressure inside the battery cell is relatively large, the winding core will first deform from the outer periphery, and the middle part of the winding core will deform last. Since the explosion-proof notch is arranged at the center of the battery bottom cover, the explosion-proof notch is directly opposite to the middle part of the winding core. When the winding core just starts to deform, the explosion-proof notch will not be blocked by the deformed winding core, improving the stability of the explosion-proof pressure relief of the battery. Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of the single battery of the present utility model;

[0018] Figure 2 is a schematic structural diagram of the battery bottom cover in Specific Embodiment 1 of the present utility model;

[0019] Figure 3 of the present utility model Figure 2 is an enlarged view of Area A;

[0020] Figure 4 is a schematic structural diagram of the battery bottom cover in Specific Embodiment 2 of the present utility model;

[0021] Figure 5 is a top view structural diagram of the battery bottom cover in Specific Embodiment 2 of the present utility model;

[0022] Figure 6 is a top view structural diagram of the battery bottom cover in Specific Embodiment 3 of the present utility model;

[0023] Figure 7 is a schematic structural diagram of the battery bottom cover in Specific Embodiment 4 of the present utility model;

[0024] Figure 8 of the present utility model Figure 7 is an enlarged view of Area B;

[0025] Figure 9 is a bottom cover structural diagram in Specific Embodiment 5 of the present utility model;

[0026] Description of the Reference Numerals:

[0027] 1. Battery bottom cover; 2. Welding part; 3. Reinforcing part; 4. Welding reference part; 5. Explosion-proof notch; 6. Battery cell; 7. Housing body; 8. Top cover. Detailed implementation mode

[0028] To solve the problems in the background technology, the core inventive concept of the present utility model is as follows: By thinning a part of the battery bottom cover to form a welding part, the welding part can directly weld the battery bottom cover with the negative electrode tab or the positive electrode tab of the battery cell by means of penetration welding, which can reduce the welding power, prevent the phenomenon of welding through, improve the product yield, and the tab is directly connected to the welding part, saving the bottom bus bar and reducing the battery manufacturing cost. An explosion-proof notch is provided on the battery bottom cover, which can not only omit the production processes such as explosion-proof sheet welding and detection, simplify the production process, but also form a pressure relief path inside the battery housing to quickly discharge the gas inside the battery housing, prevent the phenomenon of explosion of a single battery cell, and improve the explosion-proof and pressure relief stability of the battery.

[0029] The following further describes the present utility model in detail with reference to embodiments.

[0030] Specific embodiment 1 of the battery cell provided by the present utility model:

[0031] As Figure 1 shown, the single battery includes a battery housing and a battery cell 6 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 battery cell 6 assembly into the battery housing. After that, the battery housing is hermetically connected to the battery top cover to achieve the sealing of the single battery; of course, in other specific implementation modes, the housing body 7 and the battery bottom cover 1 can also be integrally formed.

[0032] As Figures 2-3 shown, the battery bottom cover 1 includes a flat plate and an explosion-proof notch 5 and a welding part 2 provided on the flat plate part. The area surrounded by the explosion-proof notch 5 covers or partially covers the center hole position of the end face of the battery cell 6. Preferably, the explosion-proof notch 5 is located at the center of the battery bottom cover 1.

[0033] To improve the safety performance of the battery, the shape of the explosion-proof notch 5 is at least 2 / 3 of a circle, and all welding parts are located outside 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 to release the internal pressure of the battery to the outside.

[0034] Specifically, the explosion-proof notch 5 is a complete circle, but in other specific implementation modes, the explosion-proof notch 5 can also be 2 / 3 of a circle or 3 / 4 of a circle. The specific shape of the explosion-proof notch 5 is not limited in this embodiment, as long as the explosion-proof notch 5 can play the explosion-proof role normally.

[0035] To further ensure safety, as a specific implementation, when the battery bottom cover 1 is a circular cover, the center of the circle where the explosion-proof notch 5 is located is the center position of the battery bottom cover 1. The explosion-proof notch 5 can specifically be a thin and weak part. When the internal pressure of the battery cell is relatively high, the explosion-proof notch 5 is damaged, so that the pressure inside the battery cell leaks to the outside of the battery cell. When the pressure inside the battery cell is relatively high, the battery core 6 (i.e., the wound battery core) will first deform from the outer periphery, and the middle part of the battery core 6 deforms last. Since the explosion-proof notch 5 is arranged at the center of the battery bottom cover 1, the explosion-proof notch 5 is directly opposite to the middle part of the battery core 6. When the battery core 6 just starts to deform, the explosion-proof notch 5 will not be blocked by the deformed battery core 6, and the explosion-proof performance is relatively good.

[0036] In other specific implementations, an explosion-proof valve can also be added to the battery top cover, and an explosion-proof notch 5 is arranged on the battery bottom cover 1 to form a double explosion-proof structure.

[0037] To improve the welding performance of the welding part, the flat part is locally thinned to form a welding part 2 for welding with the negative electrode tab or the positive electrode tab of the battery core 6. After the flat part is thinned, when the welding part 2 at the bottom of the battery bottom cover 1 is welded to the negative electrode tab or the positive electrode tab, 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 part is relatively thick to ensure the structural strength of the battery bottom cover 1, so as to prevent the battery bottom cover 1 from deforming during welding and improve the welding yield and product quality.

[0038] Specific embodiment 2 of the battery cell provided by the present utility model:

[0039] 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 flat part is locally thinned to form a welding part 2 for welding with the negative electrode tab or the positive electrode tab of the battery core 6. In this embodiment, with reference to Figures 4-5 , the flat part of the battery bottom cover 1 bulges upward to form a welding part 2. 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 with the negative electrode tab. The welding parts 2 are welded to the negative electrode tab or the positive electrode tab of the battery core 6 through the welding surface. The thickness of the welding parts 2 is smaller than that of the flat part. The negative electrode tab or the positive electrode tab of the battery core 6 is directly welded to the battery bottom cover 1 of the battery housing through the welding surface.

[0040] To improve the strength, the welding surface includes a straight line segment, and a sufficient distance is ensured at one 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.

[0041] In order to improve production efficiency, as a specific implementation, 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 5 , the number of the welding reference portions 4 is four, the number of the welding reference portions 4 is the same as that of the welding portions 2, and the welding reference portions 4 are protrusions protruding upward from the flat portion.

[0042] 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 one 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 electrode tab.

[0043] Of course, in other specific implementations, 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.

[0044] Specific embodiment 3 of the battery cell provided by the present utility model:

[0045] The purpose of this embodiment is to provide a single battery with a different battery housing structure. The main difference between this embodiment and specific embodiment 2 is that: in specific embodiment 2, the welding surfaces only include straight line segments. In this embodiment, referring to 6, in order to further increase the welding area, 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 1 (i.e., the center of the circle of the battery bottom cover 1), 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 portion 2, and improving the performance of the battery.

[0046] In some other specific implementations, a reinforcing portion 3 can be provided on the upper plate surface of the flat portion, or the reinforcing portion 3 can be provided on the lower plate surface of the flat portion. Compared with the technical solution of providing the reinforcing portion 3 on the lower or upper plate surface of the flat portion, making the reinforcing portion 3 protrude upward from the flat portion can reduce the weight of the flat portion, thereby reducing the weight of the battery housing and improving the weight energy density of the battery cell.

[0047] In order to further improve the battery performance, the reinforcing portion 3 is at least two arc-shaped reinforcing ribs, and the arc-shaped reinforcing ribs are evenly spaced on the same circumference with the center of the battery bottom cover 1 as the center of the circle. One end of each welding portion 2 and each arc-shaped reinforcing rib are arranged alternately on the same circumference.

[0048] Specifically, the reinforcing 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 battery bottom cover 1 as the center of symmetry. One end of the welding part 2 extends between two adjacent arc-shaped reinforcing ribs, so as to utilize the space between adjacent welding parts 2 to increase the total area of the welding surface and improve the battery performance.

[0049] However, in other embodiments, the reinforcing part 3 can also be only one annular reinforcing rib, or the reinforcing 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 reinforcing part 3 is not limited as long as the reinforcing part 3 can enhance the structural strength of the battery bottom cover 1.

[0050] However, in other specific embodiments, the reinforcing part 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 part, so as to prevent the battery bottom cover 1 from deforming during welding.

[0051] Specific embodiment 4 of the battery cell provided by the present utility model:

[0052] The difference from the above embodiment is that, referring to Figures 7-8 as shown, in this embodiment, all the welding parts are located inside the circle where the explosion-proof notch 5 is located.

[0053] Specific embodiment 5 of the battery cell provided by the present utility model:

[0054] The difference from the above embodiment is that, referring to Figure 9 as shown, in this embodiment, the explosion-proof notch 5 is located at an eccentric position on the battery bottom cover 1, and the area surrounded by the explosion-proof notch 5 does not overlap with the position of the central hole of the battery cell 6.

[0055] 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 on 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 bottom cover with a pressure relief structure, characterized in that, It includes a flat plate portion and an explosion-proof notch provided on the flat plate portion. The flat plate portion is locally thinned to form a welding portion for welding with the negative electrode tab or the positive electrode tab of the battery cell.

2. The battery bottom cover with a pressure relief structure as described in claim 1, wherein There is at least one explosion-proof notch, and the area enclosed by at least one explosion-proof notch covers or partially covers the position of the central hole on the end face of the battery cell.

3. The battery bottom cover with a pressure relief structure according to claim 2, wherein, The explosion-proof notch is circular, preferably arc-shaped, regular or irregular polygon.

4. The battery bottom cover with a pressure relief structure according to claim 3, characterized in that, The cross-sectional shape of the explosion-proof notch is at least one of trapezoidal, triangular, semi-circular or square.

5. The battery bottom cover with a pressure relief structure according to claim 1, characterized in that, There is at least one explosion-proof notch, and the area enclosed by the explosion-proof notch has no intersection with the position of the central hole on the end face of the battery cell.

6. A battery housing, comprising a body and a battery bottom cover with a pressure relief structure located at the bottom of the body, characterized in that, The battery bottom cover with a pressure relief structure is the battery bottom cover with a pressure relief structure according to any one of claims 1 to 5.

7. A single cell, comprising a housing and an electrode core installed in the battery housing, wherein the negative electrode tab or the positive electrode tab of the electrode core is directly welded to the battery bottom cover of the battery housing, and is characterized in that, The housing is the housing described in claim 6.

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