Battery shell, battery, battery pack and power utilization system

Abstract

The utility model relates to a battery shell, a battery, a battery pack and a power utilization system, the battery and the battery pack shell form the battery pack for supplying power to the power utilization system, and the battery shell of the battery comprises a shell body and a cover plate. Wherein the shell comprises an inner cavity, the inner cavity is provided with an opening, the cover plate is fixed on the shell, and the cover plate shields the opening of the inner cavity. At least one of the surface, facing the shell, of the cover plate and the surface, facing the cover plate, of the shell is provided with a first groove, a brazing seam is arranged between the cover plate and the shell, and the brazing seam is used for fixedly connecting the shell and the cover plate and sealing the inner cavity. The first groove is suitable for containing welding flux used for forming a brazing seam. The battery shell provided by the utility model adopts brazing, so that the welding difficulty is reduced, the manufacturing cost is reduced, and the residual stress and failure risk after welding are reduced.

Description

Technical Field

[0001] The present application relates to the field of battery casings, and in particular to a battery casing, a battery, a battery pack and a power system. Background Art

[0002] In the prior art, the battery shell of the battery is formed by welding the battery shell and the battery cover plate, so that the battery cavity is sealed. In order to meet the sealing requirements, the gap between the cover plate and the shell is required to be high during the assembly process, which makes the shell processing accuracy requirements and the manufacturing process more difficult, and increases the processing cost.

[0003] In the process of welding to eliminate the gap in the shell, the complex structure of the cover plate and the shell makes welding difficult, and the shell is thin. After the shell and the cover plate are melted, it is difficult to fill the gap, resulting in welding problems such as weld holes and failure to fuse the shell and the cover plate. The battery shell with poor welding cannot meet the sealing requirements. At the same time, the shell and the cover plate are easily caused by melting and then solidifying, which increases the risk of failure of the shell. Utility Model Content

[0004] In view of the above-mentioned technical problems, the present application provides a battery housing, a battery, a battery pack and a power system, which specifically include the following technical solutions:

[0005] In a first aspect, the present application provides a battery casing, comprising: a shell and a cover plate.

[0006] The shell comprises an inner cavity, the inner cavity has an opening, the cover plate is fixed on the shell, and the cover plate covers the opening of the inner cavity. At least one of the surface of the cover plate facing the shell and the surface of the shell facing the cover plate is provided with a first groove, a brazing seam is provided between the cover plate and the shell, the brazing seam is used to fix the shell and the cover plate, so that the cover plate seals the inner cavity, and the first groove is suitable for accommodating solder used to form the brazing seam.

[0007] The battery shell of the present application is provided with a first groove for accommodating solder. After the cover plate and the shell are assembled, they are heated to melt the solder, thereby forming a brazing seam structure and filling the gap between the cover plate and the shell, thereby fixing the cover plate and the shell and sealing the inner cavity.

[0008] The welding operation of the battery shell of the present application is simple, and the melting point of the solder is lower than that of the battery shell. During the welding process, the solder melts but the battery shell does not melt. The residual stress generated after welding is small, which can reduce the risk of failure of the battery shell.

[0009] In one embodiment, the first groove is located on a surface of the cover plate facing the housing.

[0010] In this embodiment, the first groove is located on the cover plate, and the solder is disposed in the first groove. After welding, the solder in the cover plate melts and forms a brazing seam.

[0011] In one embodiment, a protrusion is provided on the side of the cover plate facing the inner cavity, an outer side wall of the protrusion contacts the inner surface of the inner cavity, and the first groove is located on the outer side wall of the protrusion.

[0012] In this embodiment, the cover plate includes a protrusion, the protrusion extends into the inner cavity, and the outer wall of the protrusion contacts the inner surface of the inner cavity, the first groove is located on the outer wall of the protrusion, and after welding, the solder in the cover plate melts and forms a brazing seam, so that the protrusion is fixedly connected to the shell.

[0013] In one embodiment, the first groove includes a top surface facing the first surface, and along a vertical direction from the middle of the cover plate to the inner surface of the inner cavity, the distance between the top surface and the first surface decreases.

[0014] In this embodiment, during the welding process, the cover plate is located below the shell, and the top surface of the first groove is inclined, so that the molten solder can flow toward the cover plate under the action of gravity, thereby preventing the solder from flowing into the inner cavity.

[0015] In one embodiment, along the vertical direction from the middle of the cover plate to the inner surface of the inner cavity, the thickness of the edge portion of the cover plate increases.

[0016] In this embodiment, the edge of the cover plate is arranged to be inclined inwards, and the molten solder is retained on the raised edge, so that the soldering seam has a sufficient thickness on the side away from the inner cavity, thereby ensuring the quality of the welding.

[0017] In one embodiment, the first groove includes a bottom surface away from the first surface, and the brazing seam is higher than or flush with the bottom surface in the vertical direction.

[0018] In this embodiment, the cover plate is located below the shell during welding, and the molten solder flows from the first groove into the gap and flows toward the cover plate under the action of gravity. After cooling and solidification, the brazing seam is higher than or flush with the bottom surface of the first groove.

[0019] In one embodiment, the shell includes an isolation ring, which is arranged on the inner surface of the inner cavity and extends toward the center of the inner cavity, and the extension length of the isolation ring is greater than the spacing distance between the protrusion and the inner surface of the inner cavity.

[0020] In this embodiment, the cover plate is located above the shell during the welding process, and an isolation ring is provided on the inner surface of the inner cavity to prevent the molten solder from further flowing toward the inner cavity.

[0021] In one embodiment, the inner edge of the isolation ring is located above the outer edge of the isolation ring in the vertical direction; or

[0022] The isolation ring extends in a horizontal direction and is provided with a second groove, and the second groove is located on a surface of the isolation ring facing the cover plate.

[0023] In this embodiment, the isolation plate is tilted or a third groove is provided on the surface of the isolation ring facing the cover plate, both of which can retain the solder and prevent the molten solder from overflowing the isolation ring.

[0024] In one embodiment, the cover plate includes a third groove, the third groove is located on the first surface, and the third groove is circumferentially arranged on the outer side of the protrusion.

[0025] In this embodiment, the cover plate is provided with a third groove, which is circumferentially arranged on the outer side of the protrusion. The third groove accommodates solder, and after welding, the cover plate can also form a fixed connection with the shell.

[0026] In one embodiment, there is a gap between the contacting surfaces of the cover plate and the shell, and the brazing seam is located in the gap to seal and connect the cover plate and the shell.

[0027] In this embodiment, the cover plate and the shell are in contact with each other, and there is a gap between the contacting surfaces. After the solder melts, it fills the gap and forms a brazing seam, and the brazing seam seals and connects the cover plate and the shell.

[0028] In one embodiment, a brazing seam is provided in the first groove.

[0029] In this embodiment, after the solder in the first groove is melted, at least a portion of the solder remains in the first groove, and a soldering seam is formed after the solder is cooled.

[0030] In one embodiment, the thickness of the side wall of the housing is in the range of 0.05 mm to 0.2 mm.

[0031] In one embodiment, the material of the battery housing is aluminum or steel.

[0032] In this embodiment, a battery casing made of aluminum or steel is used to ensure the strength of the battery casing, and the melting point of the battery casing is higher than the melting point of the solder, thereby ensuring that the battery casing will not melt during the welding process.

[0033] In a second aspect, the present application also relates to a battery, comprising a battery cell and a battery casing provided in any one of the embodiments, wherein the battery cell is fixed in an inner cavity of the battery casing.

[0034] The battery provided in the second aspect of the present application adopts the battery casing provided in the first aspect of the present application, so the assembly process is simpler, the reliability of the battery casing can be improved, and the sealing and protective effect of the battery casing on the battery cell can be ensured.

[0035] In a third aspect, the present application also relates to a battery pack, comprising a battery pack housing and the above-mentioned battery, wherein the battery is disposed in the battery pack housing.

[0036] In a fourth aspect, the present application also relates to an electric power system, comprising the above-mentioned battery pack or the above-mentioned battery, wherein the battery pack or the battery is arranged inside the electric power system and is used to supply power to the electric power system.

[0037] The battery pack and power system of the present application can achieve higher safety and reliability and have a longer service life because of the use of the above-mentioned batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the battery housing structure provided in one embodiment of the present application;

[0039] Figure 2 This is a schematic diagram of the internal cross-sectional structure of a battery housing provided in one embodiment of the present application;

[0040] Figure 3 A partial schematic diagram of the internal cross-sectional structure of a battery housing provided in one embodiment of the present application;

[0041] Figure 4 A partial schematic diagram of the internal cross-sectional structure of a battery housing before welding provided in one embodiment of the present application;

[0042] Figure 5 A partial schematic diagram of the internal cross-sectional structure of a battery housing provided in another embodiment of the present application;

[0043] Figure 6 A partial schematic diagram of the internal cross-sectional structure of a battery housing provided in another embodiment of the present application;

[0044] Figure 7 This is a partial schematic diagram of the internal cross-sectional structure of a battery casing provided in another embodiment of the present application. DETAILED DESCRIPTION

[0045] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thoroughly and comprehensively understood.

[0046] The following descriptions of the embodiments are with reference to the attached diagrams to illustrate specific embodiments that the present application can be used to implement. The serial numbers for the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in the present application, unless otherwise specified, include direct and indirect connections (couplings). The directional terms mentioned in the present application, such as "upper", "lower", "front", "back", "left", "right", "inside", "outside", "side", etc., are only with reference to the directions of the attached drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application.

[0047] The present application relates to an electric power system, which includes a battery pack or a battery for power supply, wherein the battery pack includes a battery and a battery pack shell, and the battery includes a battery cell and a battery shell, wherein the battery cell is fixed in the inner cavity of the battery shell, and the battery shell is used to seal and protect the battery cell inside. The battery of the present application can be arranged in the electric power system, wherein the battery cell is used to power the electric power system, and the battery shell is used to seal the battery cell to prevent external liquid and gas from entering the inner cavity so as to maintain the stability of the working environment of the battery cell.

[0048] In order to meet the sealing requirements of the battery, the manufacturing assembly and welding precision required for the battery shell are high, and because the thickness of the battery shell is too thin, the welding difficulty of the battery shell is relatively large and it is difficult to ensure the welding quality. The battery shell of this application is welded by built-in solder to form a brazing seam to achieve the sealing protection of the battery shell. The welding difficulty is relatively low, the required welding steps are simple, and the manufacturing efficiency of the battery shell can be improved. At the same time, compared with ordinary welding, the residual stress of the battery shell after brazing is small, which can reduce the failure risk of the battery shell and improve its reliability.

[0049] See also Figure 1 and Figure 2 , Figure 1 The structure diagram of the battery housing 100 provided in one embodiment of the present application is shown. Figure 2 The schematic diagram of the internal cross-sectional structure of the battery housing 100 is shown.

[0050] The battery housing 100 provided in the present application includes a cover plate 10 and a shell 20. Among them, the shell 20 includes an inner cavity 21, and the inner cavity 21 has an opening. The cover plate 10 is fixed to the open side of the shell 20 and shields the opening of the inner cavity 21. The cover plate 10 is sealed and connected to the shell 20, and the inner cavity 21 is used to accommodate the battery cell. The battery housing 100 is also provided with two electrodes 40 spaced apart from each other. The two electrodes 40 are electrically connected to the battery cell respectively and pass through the housing 100 respectively, so that the battery cell in the housing 100 can be connected to the external circuit and provide or receive electrical energy.

[0051] exist Figure 1 and Figure 2 In the schematic diagram, the two electrodes 40 are spaced apart and arranged at the cover plate 10. In other embodiments, at least one of the two electrodes 40 may also be arranged on the housing 20, and the specific position of the electrode 40 may be arbitrarily set based on the working scenario of the battery of the present application.

[0052] See also Figure 3 A partial schematic diagram of the internal cross-sectional structure of the battery housing 100 is shown.

[0053] The cover plate 10 is generally plate-shaped. Specifically, in one embodiment, the cover plate 10 has a first surface 101 facing the inner cavity 21. A protrusion 11 is provided on the side of the cover plate 10 facing the inner cavity 21. The protrusion 11 extends from the cover plate 10 toward the inner cavity 21. Along the extending direction perpendicular to the protrusion 11, the protrusion 11 and the housing 20 are spaced apart from each other, that is, the outer side wall of the protrusion 11 and the inner surface of the inner cavity 21 are spaced apart from each other and a gap is left.

[0054] At least one of the surface of the cover plate 10 facing the shell 20 and the surface of the shell 20 facing the cover plate 10 is provided with a first groove 12, and a brazing seam 30 is provided between the cover plate 10 and the shell 20, the brazing seam 30 is fixedly connected to the cover plate 10 and the shell 20, and seals the inner cavity 21, and the first groove 12 is suitable for accommodating solder used to form the brazing seam 30. Specifically, in one embodiment, the cover plate 10 has a protrusion 11 facing the inner cavity 21, and the outer side wall of the protrusion 11 is provided with a first groove 12, and the first groove 12 extends toward the geometric center of the cover plate 10 along a direction perpendicular to the extension direction of the protrusion 11. A brazing seam 30 is provided between the outer side wall of the protrusion 11 and the inner surface of the inner cavity 21, and the brazing seam 30 is used to fix the cover plate 10 and the shell 20, so that the cover plate 10 seals the inner cavity 21.

[0055] Furthermore, in one embodiment, since the first groove 12 contains the solder 30a for forming the brazing seam 30, and there is a brazing seam 30 between the cover plate 10 and the shell 20, the surface of the cover plate 10 facing the shell 20 is the surface of the cover plate 10 in contact with the shell 20, and the surface of the shell 20 facing the cover plate 10 is the surface of the shell 20 in contact with the cover plate 10, thereby realizing that the solder 30a contained in the first groove 12 is melted at high temperature and filled between the cover plate 10 and the shell 20 to form the brazing seam 30, thereby realizing a closed connection between the cover plate 10 and the shell 20. In this embodiment, the contact between the cover plate 10 and the shell 20 can be direct contact, that is, the cover plate 10 and the shell 20 are attached and there is no other substance in between, and the contact can also be indirect contact, that is, the two are attached through other substances, such as the brazing seam 30, an insulating member, etc.

[0056] In addition, in other embodiments, since the purpose of setting the first groove 12 is to ensure that the solder 30a is set in the first groove 12, it is melted at high temperature and filled between the cover plate 10 and the shell 20 to form a brazing seam 30, thereby realizing a closed connection between the cover plate 10 and the shell 20. Therefore, the surface of the cover plate 10 facing the shell 20 can also be the surface of the cover plate 10 and the inner cavity 21, and the surface of the shell 20 facing the cover plate 10 can also be the surface of the inner cavity 21 of the shell 20. That is, after the first groove 12 is set on this surface, the solder 30a can flow between the cover plate 10 and the shell 20 through this surface to form a brazing seam 30.

[0057] Specifically, see Figure 4 A partial schematic diagram of the internal cross-sectional structure of the battery housing 100 before welding.

[0058] In some embodiments, Figure 4 As shown, the solder 30a is filled in the first groove 12, and the brazing seam 30 is formed by welding the solder 30a. In this embodiment, the solder 30a fills the first groove 12. In other embodiments, the solder 30a may not fill the first groove 12, and the volume of the solder 30a disposed in the first groove 12 may be adjusted based on the size of the gap between the cover plate 10 and the housing 20.

[0059] Specifically, in the manufacturing process of the battery housing 100 of the present application, taking the first groove 12 located on the cover plate 10 as an example, first, the solder 30a is placed in the first groove 12 of the cover plate 10. Then, the cover plate 10 and the shell 20 are assembled, and the protrusion 11 of the cover plate 10 first extends into the inner cavity 21 to guide the assembly of the cover plate 10 and the shell 20. There is a gap in the horizontal direction between the assembled cover plate 10 and the shell 20. Finally, the solder 30a set in advance at the first groove 12 is heated. Under the action of gravity, the molten solder 30a flows into the first groove 12 and fills the gap between the cover plate 10 and the shell 20, and the brazing seam 30 is formed after the solder 30a is cooled and solidified. The brazing seam 30 fixes the cover plate 10 and the shell 20, and can separate the inner cavity 21 from the outside to ensure the sealing of the battery housing 100.

[0060] It can be understood that in the welding process of the battery shell 100 of the present application, the solder 30a is set in the first groove 12 in advance, and it is only necessary to heat and melt the solder 30a so that the molten solder 30a flows into the gap between the cover plate 10 and the shell 20 under the action of gravity. After the solder 30a is cooled and solidified, a brazing seam 30 is formed to achieve a fixed connection between the cover plate 10 and the shell 20, and the inner cavity 21 is sealed. In the welding process of the battery shell 100 of the present application, the steps required for welding can be reduced, the difficulty of welding can be reduced, and the welding operation can be simplified. At the same time, the solder 30a is set in the first groove 12 in advance, which reduces the operating steps of the processing technology, reduces the process difficulty, and can improve the manufacturing efficiency of the battery shell 100.

[0061] At the same time, the battery shell 100 of the present application is brazed, and the melting point of the solder 30a is lower than the melting points of the cover plate 10 and the shell 20. During the welding process, only the solder 30a melts, and the cover plate 10 and the shell 20 do not melt, which can ensure the integrity of the appearance of the cover plate 10 and the shell 20. At the same time, during the welding process of the battery shell 100, only the solder 30a melts and then solidifies, which can reduce the residual stress generated after welding, reduce the deformation of the battery shell 100 caused by welding, and thus reduce the failure risk of the battery shell 100.

[0062] Therefore, the battery housing 100 in the battery of the present application can simplify the welding process and improve the production efficiency of the battery housing 100. The battery housing 100 can also reduce the residual stress after welding, reduce the risk of failure, and thus improve the reliability of the battery housing 100 to ensure a longer-term battery cell sealing protection effect.

[0063] In one embodiment, the cover plate 10 is provided with a protrusion 11, the outer side wall of the protrusion 11 contacts the inner surface of the inner cavity 21, the first groove 12 is located on the outer side wall of the protrusion 11, and the solder 30a is disposed in the first groove 12. After welding, the solder 30a forms a brazing seam 30, which can also fix the cover plate 10 and the housing 20 and seal the inner cavity 21.

[0064] In another embodiment, the cover plate 10 includes a third groove, the third groove is located on the first surface 101 of the cover plate 10, the third groove is circumferentially arranged outside the protrusion 11, and the solder 30a is arranged in the third groove. After welding, the solder 30a forms a brazing seam 30, and the brazing seam 30 can also fix the cover plate 10 and the shell 20 and seal the inner cavity 21.

[0065] In one embodiment, the side wall of the cover plate 10 contacts the shell 20, the first groove can be set on the side wall of the cover plate 10, the solder 30a is set in the first groove 12, and the solder 30a forms a brazing seam 30 after welding. The brazing seam 30 can also fix the cover plate 10 and the shell 20 and seal the inner cavity 21.

[0066] In another embodiment, the first groove 12 can also be arranged on the shell 20, the first groove 12 is located on the inner wall of the inner cavity 21, the solder 30a is arranged in the first groove 12, and after welding, the solder 30a forms a brazing seam 30, and the brazing seam 30 can also fix the cover plate 10 and the shell 20 and seal the inner cavity 21.

[0067] There are two ways to weld the cover plate 10 and the shell 20. In one way, the cover plate 10 can be located below the shell 20 in the vertical direction during welding; in another way, the cover plate 10 can be located above the shell 20 in the vertical direction during welding. Because the molten solder 30a has fluidity during welding, the solder 30a flows in different directions under the action of gravity, so that the shapes and positions of the brazing seams 30 formed by the two ways are also different.

[0068] See also Figure 5 The partial schematic diagram of the internal cross-sectional structure of the battery housing 100 provided in another embodiment of the present application is shown. In this embodiment, the battery housing 100 is welded and formed in the above-mentioned "cover plate 10 is located below the housing 20 in the vertical direction" during the welding process.

[0069] Specifically, Figure 5 As shown, the first groove 12 is located on the side wall of the protrusion 11, and the first groove 12 includes a bottom surface 122 away from the first surface 101, and the brazing seam 30 is higher than or flush with the bottom surface 122 in the vertical direction. In this embodiment, when the cover plate 10 and the shell 20 are welded, the cover plate 10 is located below the shell 20 in the vertical direction, and the molten solder 30a flows from the first groove 12 into the gap between the cover plate 10 and the shell 20 under the action of gravity, and flows toward the cover plate 10, thereby forming the brazing seam 30 that is higher than or flush with the bottom surface 122 in the vertical direction.

[0070] In one embodiment, if Figure 5 As shown, the first groove 12 includes a top surface 121 facing the first surface 101, and the distance between the top surface 121 and the first surface 101 decreases along the vertical direction from the middle of the cover plate 10 to the inner surface of the inner cavity 21. In this embodiment, when the cover plate 10 and the shell 20 are welded, the cover plate 10 is located below the shell 20 in the vertical direction, and the molten solder 30a flows toward the cover plate 10 under the action of gravity. The top surface 121 of the first groove 12 is set to be inclined, so that the molten solder 30a can flow into the gap between the cover plate 10 and the shell 20, thereby realizing the welding of the cover plate 10 and the shell 20.

[0071] In one embodiment, if Figure 5As shown, the cover plate 10 includes an edge portion along the outer side of the outer wall of the protrusion 11, and the thickness of the edge portion of the cover plate 10 increases along the vertical direction from the middle of the cover plate 10 to the inner surface of the inner cavity 21. In this embodiment, when the cover plate 10 is welded to the shell 20, the cover plate 10 is located below the shell 20 in the vertical direction, and the molten solder 30a flows toward the cover plate 10 under the action of gravity. The inclined edge portion of the cover plate 10 and the outer side of the protrusion 11 form a receiving area for the solder 30a. When the solder 30a flows to the edge portion of the cover plate 10, the inclined edge portion can retain the solder 30a, so that the brazing seam 30 formed by cooling and solidification has a sufficient thickness on the side away from the inner cavity 21, ensuring the sealing effect after welding.

[0072] In other embodiments, the first groove 12 may also be located on the side wall of the cover plate 10. Setting the surface of the first groove 12 away from the first surface 101 to be inclined can also facilitate the molten solder 30a to flow into the gap between the cover plate 10 and the shell 20, thereby achieving welding of the cover plate 10 and the shell 20.

[0073] See also Figure 6 The partial schematic diagram of the internal cross-sectional structure of the battery housing provided in another embodiment of the present application is shown. In this embodiment, the battery housing 100 is welded and formed in the above-mentioned way of "the cover plate 10 is located above the housing 20 in the vertical direction" during the welding process.

[0074] Specifically, Figure 6 As shown, the brazing seam 30 is lower than or flush with the top surface 121 of the first groove 12 in the vertical direction. In this embodiment, when the cover plate 10 is welded to the shell 20, the cover plate 10 is located above the shell 20 in the vertical direction. Under the action of gravity, the molten solder 30a flows from the first groove 12 into the gap between the cover plate 10 and the shell 20 and flows toward the inner cavity 21. Then, the brazing seam 30 is formed which is lower than or flush with the top surface 121 in the vertical direction.

[0075] In one embodiment, if Figure 6 As shown, the shell 20 includes an isolation ring 50, which is arranged on the inner surface of the inner cavity 21 and extends toward the center of the inner cavity 21. The extension length of the isolation ring 50 is greater than the distance between the protrusion 11 and the inner surface of the inner cavity 21. In this embodiment, when the cover plate 10 and the shell 20 are welded, the cover plate 10 is located above the shell 20 in the vertical direction, and the molten solder 30a flows from the first groove 12 toward the inner cavity 21 under the action of gravity. After the solder 30a flows out of the gap between the cover plate 10 and the shell 20, the isolation ring 50 can block the solder 30a, prevent the solder 30a from further flowing toward the inner cavity 21, and prevent the solder 30a with a higher temperature from approaching or contacting the battery cell in the inner cavity 21, thereby damaging the battery cell or affecting its working environment, affecting the normal operation of the battery cell.

[0076] See also Figure 7 A partial schematic diagram of the internal cross-sectional structure of a battery housing 100 provided in another embodiment of the present application is shown.

[0077] Specifically, Figure 7 As shown, the inner edge of the isolation ring 50 is located above the outer edge of the isolation ring 50 in the vertical direction. In this embodiment, when the cover plate 10 is welded to the shell 20, the cover plate 10 is located above the shell 20 in the vertical direction, and the molten solder 30a flows toward the inner cavity 21 under the action of gravity. The inclined isolation ring 50 and the inner surface of the inner cavity 21 form a receiving area for the solder 30a, which is conducive to the solder 30a remaining in the isolation ring 50. The retained solder 30a enables the brazing seam 30 formed by cooling and solidification to form a sufficient thickness on the side facing the inner cavity 21, thereby ensuring the sealing effect after welding.

[0078] In another embodiment, the isolating ring 50 extends in the horizontal direction and is provided with a second groove, and the second groove is located on the surface of the isolating ring 50 facing the cover plate 10. In this embodiment, when the cover plate 10 is welded to the shell 20, the cover plate 10 is located above the shell 20 in the vertical direction, and the solder 30a flows toward the inner cavity 21 under the action of gravity. The second groove provided on the surface of the isolating ring 50 facing the cover plate 10 can also retain the molten solder 30a, and can also enable the brazing seam 30 to form a sufficient thickness on the side facing the inner cavity 21, thereby ensuring the sealing effect after welding.

[0079] In one embodiment, if Figure 7 As shown, the distance between the bottom surface 122 and the first surface 101 increases along the vertical direction from the middle of the cover plate 10 to the inner surface of the inner cavity 21. In this embodiment, when the cover plate 10 and the housing 20 are welded, the cover plate 10 is located above the housing 20 in the vertical direction, and the molten solder 30a flows toward the inner cavity 21 under the action of gravity. The inclined bottom surface 122 of the first groove 12 is provided to facilitate the molten solder 30a to flow into the gap between the cover plate 10 and the housing 20 under the action of gravity.

[0080] In other embodiments, the first groove 12 may also be located on the side wall of the cover plate 10. Setting the surface of the first groove 12 inclined toward the first surface 101 can also facilitate the molten solder 30a to flow into the gap between the cover plate 10 and the shell 20, thereby achieving welding of the cover plate 10 and the shell 20.

[0081] In some embodiments, the thickness of the side wall of the housing 20 ranges from 0.05 mm to 0.20 mm. It is understandable that the battery housing 100 of the present application is relatively thin, and the thin-walled housing melts to fill the gap during ordinary welding, which easily produces weld holes, making the sealing of the battery housing 100 invalid. Therefore, the present application adopts brazing, and the battery housing 100 does not melt during welding, avoiding welding problems such as weld holes, thereby ensuring the integrity of the appearance of the battery housing 100.

[0082] In some embodiments, the material of the battery housing 100 is aluminum or steel. Aluminum or steel can ensure the strength of the battery housing 100. At the same time, the melting point of aluminum or steel is higher than the melting point of the solder 30a, and the temperature during the welding process is higher than the melting point of the solder 30a, and lower than the melting point of the material of the battery housing 100, so that only the solder 30a melts, and the battery housing 100 does not melt, thereby ensuring the integrity of the appearance of the battery housing 100.

[0083] In one embodiment, the distance from the protrusion 11 to the edge of the cover plate 10 increases along the vertical direction toward the inner cavity 21. During the assembly process of the cover plate 10 and the housing 20, the protrusion 11 of the cover plate 10 first extends into the inner cavity 21 of the housing 20 and moves toward the inner cavity 21, thereby guiding the assembly of the cover plate 10 and the housing 20.

[0084] In this embodiment, along the vertical direction toward the inner cavity 21, the distance between the protrusion 11 and the edge of the cover plate 10 increases. During the assembly process, the end of the protrusion 11 is smaller, which is convenient for extending into the inner cavity 21 and guiding the installation of the cover plate 10, thereby reducing the difficulty of assembling the cover plate 10 and the shell 20 and improving the assembly efficiency of the cover plate 10 and the shell 20.

[0085] In one embodiment, the cover plate 10 and the shell 20 are in contact with each other, and there is a gap between the surfaces where the cover plate 10 and the shell 20 are in contact with each other. After the solder 30a in the first groove 12 is melted, the solder 30a flows into and fills the gap to form a brazing seam 30, so that the cover plate 10 and the shell 20 are sealed and connected.

[0086] In one embodiment, the cover plate 10 and the shell 20 are in contact with each other, and there is a gap between the surfaces where the cover plate 10 and the shell 20 are in contact with each other. The solder 30a in the first groove 12 melts and flows into the gap between the cover plate 10 and the shell 20, so that the cover plate 10 and the shell 20 are sealed and connected. At the same time, part of the solder 30a remains in the first groove 12, and the solder 30a forms a brazing seam 30 after cooling. The first groove 12 is provided with a brazing seam 30.

[0087] In another embodiment, the cover plate 10 and the shell 20 are in contact with each other, and the solder 30 a in the first groove 12 melts and forms a brazing seam 30 , so that the cover plate 10 and the shell 20 are sealed and connected, and the formed brazing seam 30 is located in the first groove 12 .

[0088] In some preferred embodiments, Figure 3 As shown, the distance from the side of the first groove 12 of the cover plate 10 away from the outer wall of the protrusion 11 to the outer wall of the protrusion 11 is D, and the distance from the top surface 121 to the bottom surface 122 of the first groove 12 is W, the range of D is 0.2mm-1.0mm, and the range of W is 0.2mm-1.0mm.

[0089] It is understandable that too large W and D will result in too much solder 30a flowing into the gap between the cover plate 10 and the shell 20, and too much solder 30a will easily overflow the gap; too small W and D will result in insufficient solder 30a flowing into the gap between the cover plate 10 and the shell 20, resulting in insufficient thickness of the brazing seam 30 formed by cooling and solidification, and the sealing and protection effect of the inner cavity 21 cannot be guaranteed. Therefore, by limiting the range of W and D, the first groove 12 can accommodate an appropriate amount of solder 30a, which will not affect the battery cell of the battery of the present application, and can also ensure the quality of the brazing seam 30, thereby achieving the sealing of the battery shell 100.

[0090] In some preferred embodiments, Figure 4 As shown, the distance from the top surface 121 to the first surface 101 of the cover plate 10 is L1, and the range of L1 is 0.2mm-1.0mm. In this embodiment, when the cover plate 10 is welded to the shell 20, the cover plate 10 is located below the shell 20 in the vertical direction, and the solder 30a flows toward the cover plate 10 under the action of gravity. When L1 is too small, the thickness of the formed brazing seam 30 in the vertical direction is insufficient to meet the sealing requirements of the battery shell 100; when L1 is too large, the gap between the cover plate 10 and the shell 20 is too large, and more solder 30a is required to fill the gap. The thickness of the formed brazing seam 30 in the vertical direction is insufficient, and it is difficult to achieve the sealing protection of the battery shell 100. The appropriate L1 can form a brazing seam 30 of sufficient thickness to meet the sealing requirements of the battery shell 100.

[0091] In other preferred embodiments, Figure 4 As shown, the distance from the bottom surface 122 to the surface of the protrusion 11 facing the inner cavity 21 is L2, and the range of L2 is 0.2mm-1.0mm. In this embodiment, when the cover plate 10 is welded to the shell 20, the cover plate 10 is located above the shell 20 in the vertical direction, and the solder 30a flows toward the inner cavity 21 under the action of gravity. A suitable L2 can also form a soldering seam 30 of sufficient thickness to meet the sealing requirements of the battery shell 100.

[0092] In some preferred embodiments, Figure 5 As shown, the cover plate 10 includes a second surface 102 away from the inner cavity 21 , and the angle between the top surface 121 and the second surface 102 is α1 , and the range of α1 is 15°-45°.

[0093] In this embodiment, when the cover plate 10 and the shell 20 are welded, the cover plate 10 is located below the shell 20 in the vertical direction, and the solder 30a flows toward the cover plate 10 under the action of gravity. When α1 is too large, the speed at which the molten solder 30a flows into the gap between the cover plate 10 and the shell 20 is too fast, which easily causes the solder 30a to overflow from the side of the gap away from the inner cavity 21; when α1 is too small, the speed at which the molten solder 30a flows into the gap between the cover plate 10 and the shell 20 is too slow, resulting in extended welding time and reduced manufacturing efficiency. Therefore, an appropriate α1 is conducive to the molten solder 30a flowing from the first groove 12 into the gap between the cover plate 10 and the shell 20 at an appropriate speed.

[0094] In other preferred embodiments, Figure 7 As shown, the angle between the bottom surface 122 and the second surface 102 of the cover plate 10 is α2, and the range of α2 is 15°-45°. In this embodiment, when the cover plate 10 and the shell 20 are welded, the cover plate 10 is located above the shell 20 in the vertical direction, and the solder 30a flows toward the inner cavity 21 under the action of gravity. Setting a proper α2 can also make the solder 30a flow from the first groove 12 into the gap between the cover plate 10 and the shell 20 at a suitable speed.

[0095] In some preferred embodiments, Figure 5 As shown, the included angle between the first surface 101 and the second surface 102 of the edge portion of the cover plate 10 facing the inner cavity 21 is β1, and the range of β1 is 3°-15°.

[0096] In this embodiment, when the cover plate 10 is welded to the shell 20, the cover plate 10 is located below the shell 20 in the vertical direction, and the solder 30a flows toward the cover plate 10 under the action of gravity. When β1 is too large, the gap at the edge of the cover plate 10 is larger, and more solder 30a is required to fill the gap to seal the cover plate 10 and the shell 20; when β1 is too small, too little solder 30a is allowed to remain at the edge of the cover plate 10, which easily leads to insufficient thickness of the brazing seam 30 on the side away from the inner cavity 21, making it difficult to ensure the sealing of the battery shell 100. Therefore, an appropriate β1 is conducive to the molten solder 30a remaining at the edge of the cover plate 10.

[0097] In other preferred embodiments, the angle between the surface of the isolation ring 50 away from the inner cavity 21 and the second surface 102 of the cover plate 10 is β2, and the range of β2 is 3°-15°. In this embodiment, when the cover plate 10 is welded to the shell 20, the cover plate 10 is located above the shell 20 in the vertical direction, and the solder 30a flows toward the inner cavity 21 under the action of gravity. Setting an appropriate β2 is also conducive to the molten solder 30a remaining in the isolation ring 50, thereby preventing the solder 30a from further flowing toward the inner cavity 21.

[0098] In some preferred embodiments, the distance between the protrusion 11 and the inner surface of the inner cavity 21 along the horizontal direction ranges from 0.01 mm to 0.20 mm. The distance between the cover plate 10 and the shell 20 is set within a suitable range, which can limit the size of the gap. A too large gap space needs to be filled with more solder 30a to achieve the sealing of the battery shell 100, and a too small gap space will increase the difficulty of assembling the cover plate 10 and the shell 20.

[0099] The specific development of the above various embodiments can control the volume of the molten solder 30a flowing into the inner cavity 21, and control the volume occupied by the formed brazing seam 30 in the inner cavity 21. On the one hand, it can prevent the high-temperature solder 30a from contacting the battery cell, which may cause damage to the battery cell, and on the other hand, it is conducive to controlling the internal space size of the inner cavity 21 and ensuring the reliable sealing connection between the cover plate 10 and the shell 20.

[0100] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0101] It should be understood that the application of this application is not limited to the above examples. For ordinary technicians in this field, they can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the claims attached to this application. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments are implemented, and equivalent changes made according to the claims of this application still fall within the scope covered by this application.

Claims

1. A battery casing, characterized in that: comprising a shell and a cover plate; The shell comprises an inner cavity having an opening, and the cover is fixed to the shell and covers the opening; At least one of a surface of the cover plate facing the shell and a surface of the shell facing the cover plate is provided with a first groove, a brazing seam is provided between the cover plate and the shell, the brazing seam is used to seal and connect the shell and the cover plate so that the cover plate seals the inner cavity, and the first groove is suitable for accommodating solder used to form the brazing seam.

2. The battery casing according to claim 1, characterized in that: The first groove is located on a surface of the cover plate facing the housing.

3. The battery casing according to claim 1 or 2, characterized in that: A protrusion is provided on one side of the cover plate facing the inner cavity, an outer side wall of the protrusion contacts the inner surface of the inner cavity, and the first groove is located on the outer side wall of the protrusion.

4. The battery casing according to claim 3, characterized in that: The cover plate also has a first surface facing the inner cavity, the first surface is arranged around the protrusion, and the first groove includes a top surface facing the first surface. Along the vertical direction from the middle of the cover plate to the inner surface of the inner cavity, the distance between the top surface and the first surface decreases.

5. The battery housing according to claim 3, characterized in that: Along the vertical direction from the middle of the cover plate to the inner surface of the inner cavity, the thickness of the edge portion of the cover plate increases.

6. The battery housing according to claim 3, characterized in that: The cover plate also has a first surface facing the inner cavity, the first surface is arranged around the protrusion, the first groove includes a bottom surface away from the first surface, and the brazing seam is higher than or flush with the bottom surface in the vertical direction.

7. The battery housing according to claim 3, characterized in that: The cover plate also has a first surface facing the inner cavity, the first surface is arranged around the protrusion, the first groove includes a bottom surface away from the first surface, and the distance between the bottom surface and the first surface increases along the vertical direction from the middle of the cover plate to the inner surface of the inner cavity.

8. The battery casing according to claim 3, characterized in that: The shell includes an isolating ring, which is arranged on the inner surface of the inner cavity and extends toward the center of the inner cavity. The isolating ring is spaced apart from the protrusion along the vertical direction.

9. The battery casing according to claim 8, characterized in that: The inner edge of the isolation ring is located above the outer edge of the isolation ring in the vertical direction; and / or The isolation ring extends in a horizontal direction and is provided with a second groove, and the second groove is located on a surface of the isolation ring facing the cover plate.

10. The battery housing according to claim 3, characterized in that: The cover plate also has a first surface facing the inner cavity, the first surface is arranged around the protrusion, and the cover plate includes a third groove, the third groove is located on the first surface, and the third groove is circumferentially arranged on the outer side of the protrusion.

11. The battery housing according to claim 1, characterized in that: There is a gap between two surfaces of the cover plate and the shell that contact each other, and the brazing seam is located in the gap to seal and connect the cover plate and the shell.

12. The battery casing according to claim 1 or 11, characterized in that: The brazing seam is arranged in the first groove.

13. The battery housing according to claim 1, wherein: The shell wall thickness of the shell is in the range of 0.05mm-0.20mm.

14. A battery, characterized in that: It comprises a battery core and a battery casing according to any one of claims 1 to 13, wherein the battery core is fixed in an inner cavity of the battery casing.

15. A battery pack, characterized in that: It comprises the battery as claimed in claim 14 and a battery pack casing, wherein the battery is arranged in the battery pack casing.

16. An electricity system, characterized in that: Including the battery according to claim 14 or the battery pack according to claim 15.

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