Battery pack and electric device

Abstract

The application discloses a battery pack and an electric equipment, and relates to the technical field of new energy batteries. The battery pack comprises a battery cell and a box structure, the battery cell is arranged in the box structure, and the box structure comprises: a first box; a second box which is welded with the first box and forms a welding area; a first protective film which is attached to one side of the first box away from the second box and covers the welding area; and a second protective film which is attached to one side of the second box away from the first box and covers the welding area. The battery pack provided by the application can improve the corrosion resistance of the welding area of the box structure.

Description

Technical Field

[0001] This application relates to the field of new energy battery technology, and in particular to a battery pack and electrical equipment. Background Technology

[0002] In power batteries, the requirement for corrosion resistance is mainly to ensure the long-term reliability of the power battery under the influence of the external environment, including requirements for mechanical reliability, airtightness, and appearance.

[0003] In related technologies, the welded areas of the power battery pack casing are prone to corrosion, which affects the safety of the power battery pack. Utility Model Content

[0004] This application provides a battery pack and electrical device to improve the corrosion resistance of the welded areas of the enclosure structure.

[0005] This application provides a battery pack, including battery cells and a housing structure, wherein the battery cells are disposed in the housing structure, and the housing structure includes: First box; The second housing is welded to the first housing, forming a welding area; The first protective film is attached to the side of the first housing opposite to the second housing and covers the welding area; The second protective film is attached to the side of the second housing opposite to the first housing and covers the welding area.

[0006] In some possible implementations, the first housing includes a first housing body and a first flange edge; The first box body is provided with a receiving cavity and an opening located at one end of the first box body. The first flange is connected to the end of the first box body near the opening and is located on the side of the first box body away from the receiving cavity. The first flange is welded to the second box body. The first protective film is attached to the side of the first flange that is away from the second box body.

[0007] In some possible implementations, the first flange edge is configured as an opening ring structure disposed around the opening, and the first flange edge has a first end and a second end along the circumferential direction of the first flange edge. Both the first protective film and the welding area are arranged circumferentially along the edge of the first flange, and both are configured as open ring structures; Along the circumferential direction of the first flange edge, the end of the first protective film facing the first end protrudes relative to the end of the welding area facing the first end, and the end of the first protective film facing the second end protrudes relative to the end of the welding area facing the second end.

[0008] In some possible implementations, a chamfered area is provided at the connection between the first box body and the first flange edge; The box structure also includes a third protective film, which is attached to the side of the first box body away from the accommodating cavity and covers the chamfered area.

[0009] In some possible implementations, the second enclosure includes a second enclosure body and a second flange edge, the second flange edge being disposed along the edge of the second enclosure body and connected to the second enclosure body; The second flange edge is welded to the first flange edge, and the second protective film is attached to the side of the second flange edge away from the first housing.

[0010] In some possible implementations, the second flange edge is configured as an open ring structure arranged around the periphery of the second box body, and the second flange edge has a third end and a fourth end along the circumferential direction of the second flange edge; Both the second protective membrane and the welding area are arranged circumferentially along the edge of the second flange; Along the circumferential direction of the second flange edge, one end of the second protective film facing the third end protrudes relative to the end of the welding area facing the third end, and one end of the second protective film facing the fourth end protrudes relative to the end of the welding area facing the fourth end.

[0011] In some possible implementations, the second flange edge is fitted against the first flange edge, forming a fitting gap; The enclosure structure also includes a fourth protective film, which is attached to the side surface of the first flange that is away from the first enclosure body and the side surface of the second flange that is away from the second enclosure body, and covers the joint.

[0012] In some possible implementations, the first flange edge is configured as an opening ring structure disposed around the opening, and the first flange edge has a first end and a second end along the circumferential direction of the first flange edge. The fourth protective membrane extends circumferentially along the edge of the first flange; Along the circumferential direction of the first flange edge, one end of the fourth protective film facing the first end protrudes relative to the end of the welding area facing the first end, and one end of the fourth protective film facing the second end protrudes relative to the end of the welding area facing the second end.

[0013] In some possible implementations, the thickness H1 of the first protective film is 90 μm ≤ H1 ≤ 130 μm; And / or, the thickness H2 of the second protective film is 90μm≤H2≤130μm.

[0014] In addition, this application also provides an electrical device including the battery pack described in the above embodiments.

[0015] The beneficial effects of this application are as follows: In the battery pack provided by this application, the first protective film and the second protective film cover the welding area of ​​the box structure. The first protective film and the second protective film can prevent corrosive substances from the external environment from contacting the welding area of ​​the box structure. The first protective film and the second protective film provide corrosion-resistant protection for the welding area, reducing the risk of corrosion of the welding area of ​​the battery pack during subsequent use, thereby extending the service life of the battery pack and improving the safety of battery pack use. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A three-dimensional structural schematic diagram of the battery pack is shown in some embodiments; Figure 2 Exploded structural diagrams of the battery pack in some embodiments are shown; Figure 3 A bottom view of the box structure is shown in some embodiments; Figure 4 Partial cross-sectional structural schematic diagrams of the box structure are shown in some embodiments; Figure 5 Explosion-proof structural diagrams of the first housing and the first protective membrane in some embodiments are shown; Figure 6 A schematic diagram of the structure of the first housing in some embodiments is shown; Figure 7 Schematic diagrams of the exploded structure of the second housing and the second protective membrane in some embodiments are shown; Figure 8 The diagram shows the state of the sample without protective film before the salt spray test. Figure 9 The diagram shows the state of the sample without protective film after the salt spray test. Figure 10The diagram shows the state of some samples covered with protective film before the salt spray test. Figure 11 This shows the state of another portion of the samples covered with a protective film before the salt spray test; Figure 12 This shows the state of another batch of samples covered with protective film before the salt spray test; Figure 13 The diagram shows the condition of some samples covered with protective film after the salt spray test. Figure 14 This shows the condition of another portion of the samples covered with a protective film after the salt spray test; Figure 15 The diagram shows the state of another batch of samples covered with a protective film after the salt spray test.

[0018] Explanation of key component symbols: 1000 - Box structure; 100 - First housing; 110 - First housing body; 1101 - Chamfered area; 120 - First flange edge; 121 - First end; 122 - Second end; 101 - Receiving cavity; 102 - Opening; 200 - Second box body; 210 - Second box main body; 220 - Second flange edge; 221 - Third end; 222 - Fourth end; 310 - Welding area; 320 - Fitting gap; 410 - First protective film; 420 - Second protective film; 430 - Third protective film; 440 - Fourth protective film; 2000-cell. Detailed Implementation

[0019] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0020] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0022] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0023] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0024] The inventors of this application have discovered that the casing structure 1000 of some current battery packs is made of materials that are not resistant to corrosion (such as carbon steel). During the assembly process, the casing is first treated with electrophoresis or a combination of electrophoresis and powder coating to achieve corrosion protection. Then, the casing is welded. However, the welding process damages the corrosion-resistant layer on the surface of the casing structure 1000, causing the welded areas to lose their original corrosion protection, thus leading to the failure of the anti-corrosion protection. Therefore, this application provides a battery pack that can achieve corrosion protection for the welded area 310.

[0025] like Figures 1 to 4 , Figure 6As shown, the embodiment provides a battery pack, which may include a battery cell 2000 and a housing structure 1000. The housing structure 1000 includes a first housing 100, a second housing 200, a first protective film 410, and a second protective film 420. The first housing 100 and the second housing 200 are disposed opposite to each other and cooperate to form a receiving cavity 101, in which the battery cell 2000 can be disposed. Furthermore, the first housing 100 and the second housing 200 are welded together, forming a welding area 310.

[0026] In this embodiment, the battery pack may also include a cooling structure (not shown in the figure), a battery management system (not shown in the figure), and other structures, all of which can be housed within the housing structure 1000. It is understood that the accompanying drawings only show a portion of the battery pack's structure and not the entire structure.

[0027] In some embodiments, the first protective film 410 may be adhered to the side of the first housing 100 opposite to the second housing 200 and cover the welding area 310. The second protective film 420 may be adhered to the side of the second housing 200 opposite to the first housing 100 and cover the welding area 310.

[0028] In this embodiment, the first protective film 410 and the second protective film 420 cover the welding area 310 of the housing structure 1000, preventing corrosive substances such as gases and / or liquids from the external environment from contacting the welding area 310 of the housing structure 1000. Therefore, the first protective film 410 and the second protective film 420 provide corrosion-resistant protection for the welding area 310, reducing the risk of corrosion of the welding area 310 during subsequent use of the battery pack, thereby extending the service life of the battery pack and improving its safety.

[0029] like Figures 4 to 7 As shown, in some embodiments, the first housing 100 may include an integral first housing body 110 and a first flange edge 120. The first housing body 110 may be in the shape of a cover. A receiving cavity 101 may be formed in the first housing body 110. Furthermore, the first housing body 110 is provided with an opening 102 at one end of the first housing body 110, and the opening 102 may communicate with the receiving cavity 101, allowing the battery cell 2000 to be transferred into the receiving cavity 101 through the opening 102. In some embodiments, the first flange edge 120 may be connected to the end of the first housing body 110 near the opening 102, and is located on the side of the first housing body 110 opposite to the receiving cavity 101. Additionally, the first flange edge 120 may be arranged around the periphery of the first housing body 110 facing the opening 102, and the first flange edge 120 is configured as an open ring structure arranged around the opening 102, i.e., the first flange edge 120 is a non-closed ring structure.

[0030] In some embodiments, the second housing 200 may include an integral second housing body 210 and a second flange edge 220. The second housing body 210 may be generally plate-shaped, and the second flange edge 220 may be disposed around the edge of the second housing body 210. Furthermore, the second flange edge 220 is configured as an open ring structure surrounding the periphery of the second housing body 210, meaning the second flange edge 220 is also a non-closed ring structure.

[0031] In this embodiment, the second box body 210 can cover the opening 102 of the first box body 110, and the second flange edge 220 can be fitted with the first flange edge 120. Accordingly, a fitting gap 320 can be formed between the first flange edge 120 and the second flange edge 220. In addition, the first flange edge 120 can be welded to the second flange edge 220 to form a welding area 310, thereby achieving closure of the opening 102 of the first box body 110.

[0032] In some embodiments, the first protective film 410 may be adhered to the side of the first flange edge 120 opposite to the second flange edge 220 and cover the welding area 310. The second protective film 420 may be adhered to the side of the second flange edge 220 opposite to the first flange edge 120 and cover the welding area 310.

[0033] In some embodiments, the first flange edge 120 has a first end 121 and a second end 122 along its circumference. In some embodiments, the second flange edge 220 has a third end 221 and a fourth end 222 along its circumference. Accordingly, the welding area 310 may extend along the circumference of the first flange edge 120 and the second flange edge 220, and presents an open ring structure. In addition, along the circumference of the first flange edge 120, there is a gap between both ends of the welding area 310 and the edges of the two ends of the first flange edge 120. And the gap distance between the end of the welding area 310 facing the first end 121 and the edge of the first end 121 may be equal to the gap distance between the end of the welding area 310 facing the second end 122 and the edge of the second end 122.

[0034] In some embodiments, the first protective film 410 may be disposed circumferentially along the first flange edge 120. Correspondingly, the first protective film 410 may also have an open ring structure and have two ends. Along the circumferential direction of the first flange edge 120, the end of the first protective film 410 facing the first end 121 may protrude relative to the end of the welding area 310 facing the first end 121, and the end of the first protective film 410 facing the second end 122 may protrude relative to the end of the welding area 310 facing the second end 122. That is, the extension length of the first protective film 410 along the circumferential direction of the first flange edge 120 may be greater than the extension length of the welding area 310 along the circumferential direction of the first flange edge 120. Therefore, in the extension length direction of the welding area 310, each part of the welding area 310 can be covered by the first protective film 410, so that each part of the welding area 310 can be protected against corrosion.

[0035] In some embodiments, the end of the first protective film 410 facing the first end 121 may have a gap with the edge of the first end 121, and the gap length may be set to 7±0.5mm. The end of the first protective film 410 facing the second end 122 may have a gap with the edge of the second end 122, and the gap length may be set to 7±0.5mm.

[0036] In some embodiments, the width of the first protective film 410 may be greater than the width of the welding area 310. Both the width of the first protective film 410 and the width of the welding area 310 refer to the radial dimension along the first flange edge 120. The width of the welding area 310 is typically set to 2.4 ± 0.1 mm. In one embodiment, the width of the first protective film 410 may be set to 10 mm. Furthermore, along the radial direction of the first flange edge 120, the first protective film 410 may protrude from the opposite sides of the welding area 310. Along the radial direction of the first flange edge 120, the first protective film 410 can completely cover the welding area 310.

[0037] In some embodiments, the second protective film 420 may extend circumferentially along the second flange edge 220 and has two ends. One end of the second protective film 420 facing the third end 221 protrudes relative to the end of the welding area 310 facing the third end 221, and the other end of the second protective film 420 facing the fourth end 222 may protrude relative to the end of the welding area 310 facing the fourth end 222. Thus, in the extending length direction of the welding area 310, each portion of the welding area 310 can be covered by the second protective film 420, so that each portion of the welding area 310 can receive corrosion-resistant protection.

[0038] In some embodiments, the arrangement and dimensions of the second protective film 420 on the second flange edge 220 may be similar to the arrangement and dimensions of the first protective film 410 on the first flange edge 120, and will not be described again here.

[0039] like Figure 4 and Figure 6 As shown, in some embodiments, a chamfered area 1101 is provided at the connection between the first box body 110 and the first flange edge 120. The box structure 1000 also includes a third protective film 430, which can cover the chamfered area 1101 and is located on the side of the first box body 110 opposite to the receiving cavity 101. In some embodiments, the width of the third protective film 430 can be set to 10±0.5mm, which can completely cover the chamfered area 1101.

[0040] like Figures 4 to 7 As shown, in some embodiments, the housing structure 1000 further includes a fourth protective film 440. The fourth protective film 440 can be adhered to the surface of the first flange edge 120 facing away from the first housing body 110, and the surface of the second flange edge 220 facing away from the second housing body 210. That is, the fourth protective film 440 can be simultaneously arranged around the periphery of the first flange edge 120 and the periphery of the second flange edge 220. Moreover, the fourth protective film 440 can cover the bonding gap 320 between the first flange edge 120 and the second flange edge 220. Thus, the fourth protective film 440 can prevent external environmental corrosive substances such as moisture from entering the bonding gap 320 and corroding the welding position, thereby achieving all-round corrosion resistance protection for the welding position.

[0041] In some embodiments, the fourth protective membrane 440 may also extend circumferentially along the first flange edge 120 and the second flange edge 220, i.e., the fourth protective membrane 440 may also have an open ring structure. The end of the fourth protective membrane 440 facing the first end 121 may protrude relative to the end of the welding area 310 facing the first end 121, and the end of the fourth protective membrane 440 facing the second end 122 may protrude relative to the end of the welding area 310 facing the second end 122. That is, the circumferential extension length of the fourth protective membrane 440 along the first flange edge 120 may be greater than the circumferential extension length of the welding area 310 along the first flange edge 120. Furthermore, there is a gap between the end of the fourth protective membrane 440 facing the first end 121 and the edge of the first end 121, and there is also a gap between the end of the fourth protective membrane 440 facing the second end 122 and the edge of the second end 122, and the distance between the two gaps is the same. In this embodiment, the extension length of the fourth protective membrane 440 along the circumference of the first flange edge 120 can be equal to the extension length of the first protective membrane 410 along the circumference of the first flange edge 120, and both ends of the fourth protective membrane 440 protrude relative to the two ends of the welding area 310, thereby ensuring all-round corrosion protection at the welding position. In some embodiments, the height of the fourth protective membrane 440 can be set to 2mm, and the height of the fourth protective membrane 440 can refer to the dimension of the fourth protective membrane 440 along the plane perpendicular to the first flange edge 120.

[0042] like Figures 1 to 7 As shown, during the battery pack assembly process, the internal structure of the battery pack, such as the battery cell 2000, can first be installed into the receiving cavity 101 of the first box body 110. Then, the second box body 200 can be placed over the end of the first box body 100 facing the opening 102, with the second box body 210 facing the opening 102 and the second flange edge 220 facing the first flange edge 120. Then, the first flange edge 120 and the second flange edge 220 can be welded together using a welding process. Afterwards, a first protective film 410, a second protective film 420, a third protective film 430, and a fourth protective film 440 can be applied to the box structure 1000 using a spraying process. The first and second protective films 410 and 420 both cover the welding area 310, the third protective film 430 covers the chamfered area 1101 of the first box body 100, and the fourth protective film 440 covers the seam 320 between the first flange edge 120 and the second flange edge 220. In some embodiments, each protective film may be made of ultraviolet-cured paint (UV paint). During the spraying process, appropriate tooling can be used to shield the areas on the surface of the housing structure 1000 where no protective film is required, thereby preventing the UV paint from adhering to the surface where no protective film is required.

[0043] In some embodiments, before spraying UV paint, the area where the protective film is attached can be polished using a laser cleaning process to remove dirt from the surface of the welding area 310 and the high-temperature oxide layer on the weld surface. This also increases the surface roughness at the location where the protective film adheres, increasing the adhesion between the protective film and the enclosure structure 1000 and reducing the risk of the protective film detaching from the enclosure structure 1000. Then, a pre-programmed robotic arm can spray paint onto the surface of the enclosure structure 1000 to obtain a protective film with good coverage and uniform thickness (including a first protective film 410, a second protective film 420, a third protective film 430, and a fourth protective film 440). After spraying, each protective film can be cured by UV lighting. Afterward, the protective film sprayed onto the surface of the enclosure structure 1000 can be inspected and confirmed to ensure that the spraying is qualified.

[0044] In some embodiments, the thickness H1 of the first protective film 410 can be set to 90μm≤H1≤130μm, and the thickness H2 of the second protective film 420 can be 90μm≤H2≤130μm. In other embodiments, the thicknesses of the first protective film 410, second protective film 420, third protective film 430, and fourth protective film 440 can all be set to 90μm to 130μm. This ensures effective and reliable corrosion protection for the welding area 310 while reducing the amount of protective film material used and lowering material costs. In some embodiments, the thicknesses of the first protective film 410, second protective film 420, third protective film 430, and fourth protective film 440 can be set to be the same. Exemplarily, the thickness of each protective film can be set to 90μm, 95μm, 100μm, 110μm, 120μm, 125μm, 130μm, or any other value from 90μm to 130μm.

[0045] The following are relevant tests on corrosion protection of the welding position achieved by the protective film in the battery pack provided in the embodiments of this application, wherein the sample is made of stainless steel.

[0046] Table 1

[0047] like Figure 8 As shown, this diagram illustrates the state of a workpiece without a protective film before a salt spray test. Figure 9 The diagram shows the condition of a workpiece without a protective film after a salt spray test. It can be seen that the workpiece without a protective film showed significant corrosion after 120 hours (h) of salt spray testing.

[0048] like Figures 10 to 12 The diagram shows the state of the workpieces with protective films before the salt spray test. The protective film thickness is 40 μm for group Fa, 110 μm for group Fb, and 150 μm for group Fc. Figures 13 to 15 The diagram shows the state of the workpieces with protective films after a salt spray test. It can be seen that the Fa group samples exhibited edge curling after 720 hours of salt spray testing, meaning the protective film separated from the workpiece; the Fb samples showed no significant corrosion or edge curling after 720 hours of salt spray testing; and the Fc samples also showed no significant corrosion or edge curling after 720 hours of salt spray testing. This demonstrates that a protective film thickness of approximately 110 μm is sufficient to achieve effective corrosion protection while reducing material usage and saving costs. Therefore, in this embodiment, the thickness of each protective film is set to 90 μm to 130 μm, providing effective and reliable corrosion protection while also reducing material costs.

[0049] The embodiment also provides an electrical device, which may include the battery pack provided in the embodiment.

[0050] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0051] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A battery pack, characterized in that, It includes a battery cell (2000) and a housing structure (1000), wherein the battery cell is disposed in the housing structure (1000), and the housing structure (1000) includes: First box (100); The second housing (200) is welded to the first housing (100) to form a welding area (310). The first protective film (410) is attached to the side of the first housing (100) away from the second housing (200) and covers the welding area (310). The second protective film (420) is attached to the side of the second housing (200) away from the first housing (100) and covers the welding area (310).

2. The battery pack according to claim 1, characterized in that, The first housing (100) includes a first housing body (110) and a first flange edge (120); The first box body (110) is provided with a receiving cavity (101) and an opening (102) located at one end of the first box body (110). The first flange edge (120) is connected to one end of the first box body (110) near the opening (102) and is located on the side of the first box body (110) away from the receiving cavity (101). The first flange edge (120) is welded to the second box body (200). The first protective film (410) is attached to the side of the first flange edge (120) away from the second box body (200).

3. The battery pack according to claim 2, characterized in that, The first flange edge (120) is configured as an opening ring structure arranged around the opening (102). Along the circumference of the first flange edge (120), the first flange edge (120) has a first end (121) and a second end (122). The first protective film (410) and the welding area (310) are both arranged circumferentially along the first flange edge (120) and are both configured as open ring structures; Along the circumference of the first flange edge (120), one end of the first protective film (410) facing the first end (121) protrudes relative to the end of the welding area (310) facing the first end (121), and one end of the first protective film (410) facing the second end (122) protrudes relative to the end of the welding area (310) facing the second end (122).

4. The battery pack according to claim 2, characterized in that, A chamfered area (1101) is provided at the connection between the first box body (110) and the first flange edge (120). The box structure (1000) also includes a third protective film (430), which is attached to the side of the first box body (110) away from the accommodating cavity (101) and covers the chamfered area (1101).

5. The battery pack according to any one of claims 2 to 4, characterized in that, The second housing (200) includes a second housing body (210) and a second flange edge (220), the second flange edge (220) being disposed along the edge of the second housing body (210) and connected to the second housing body (210); The second flange edge (220) is welded to the first flange edge (120), and the second protective film (420) is attached to the side of the second flange edge (220) away from the first housing (100).

6. The battery pack according to claim 5, characterized in that, The second flange edge (220) is configured as an open ring structure arranged around the second box body (210). Along the circumference of the second flange edge (220), the second flange edge (220) has a third end (221) and a fourth end (222). The second protective film (420) and the welding area (310) are both arranged circumferentially along the edge of the second flange (220); Along the circumference of the second flange edge (220), one end of the second protective film (420) facing the third end (221) protrudes relative to the end of the welding area facing the third end (221), and one end of the second protective film (420) facing the fourth end (222) protrudes relative to the end of the welding area facing the fourth end (222).

7. The battery pack according to claim 5, characterized in that, The second flange edge (220) is fitted to the first flange edge (120) and forms a fitting gap (320). The box structure (1000) also includes a fourth protective film (440), which is attached to the side surface of the first flange edge (120) facing away from the first box body (110) and the side surface of the second flange edge (220) facing away from the second box body (210), and covers the bonding gap (320).

8. The battery pack according to claim 7, characterized in that, The first flange edge (120) is configured as an opening ring structure arranged around the opening (102). Along the circumference of the first flange edge (120), the first flange edge (120) has a first end (121) and a second end (122). The fourth protective membrane (440) extends circumferentially along the first flange edge (120); Along the circumference of the first flange edge (120), the end of the fourth protective film (440) facing the first end (121) protrudes relative to the end of the welding area (310) facing the first end (121), and the end of the fourth protective film (440) facing the second end (122) protrudes relative to the end of the welding area (310) facing the second end (122).

9. The battery pack according to claim 1, characterized in that, The thickness H1 of the first protective film (410) is 90μm≤H1≤130μm; And / or, the thickness H2 of the second protective film (420) is 90μm≤H2≤130μm.

10. An electrical appliance, characterized in that, Includes the battery pack as described in any one of claims 1 to 9.

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