Battery case, battery cell, battery pack, and electric device

Abstract

This application discloses a battery casing, a battery cell, a battery pack, and an electrical device, comprising: a casing body, wherein the titanium content of the casing body is 'a', and the casing body is provided with a stepped portion recessed towards the casing cavity of the casing body, the stepped portion being provided with an injection hole; a sealing member, the sealing member being disposed on the stepped portion to block the channel of the injection hole, the thickness of the sealing member being b1 (mm), the casing wall thickness of the casing body on the side where the injection hole is located being b2 (mm), b1 / b2 being b, and the area of ​​the sealing member being s (mm²). 2 Therefore, the value range of a×b×s is 1.5~45. This application can balance the welding quality between the seal and the housing body, as well as the flatness of the housing body. That is, while ensuring the welding quality between the seal and the housing body to obtain a better sealing effect, the flatness of the housing body is also guaranteed.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a battery casing, a battery cell, a battery pack, and an electrical device. Background Technology

[0002] To meet lightweight requirements, some batteries now use titanium casings, which provide sufficient strength to protect the internal cells while reducing the overall weight of the battery. To allow for electrolyte filling, injection holes need to be created in the battery casing. These holes are sealed after electrolyte filling is completed during battery production.

[0003] Currently, the common practice is to weld the seal to the injection hole to seal it. However, welding the seal to the housing body can lead to problems such as poor sealing and uneven flatness of the housing.

[0004] Therefore, how to ensure the flatness of the shell while guaranteeing the welding quality is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a battery casing that ensures both welding quality and flatness of the casing;

[0006] Another objective of this application is to provide a battery cell, battery pack, and electrical device having the aforementioned battery casing.

[0007] To achieve the above objectives, this application provides the following technical solution:

[0008] The first aspect of this application provides a battery housing, comprising:

[0009] The shell body has a titanium content of a and is provided with a stepped portion that is recessed into the shell cavity of the shell body, and the stepped portion is provided with a liquid injection hole.

[0010] A sealing element, wherein the sealing element is welded to the stepped portion using through welding to seal the channel of the injection hole, has a thickness of b1 in mm, and the wall thickness of the housing body on the side where the injection hole is located is b2 in mm, where b1 / b2 is b, and the area of ​​the sealing element is s in mm². 2 Then the value range of a×b×s is 1.5~45, and the material of the sealing element is aluminum or aluminum alloy;

[0011] The value range of 'a' is 70% to 99.7%.

[0012] The value of b ranges from 0.6 to 1.33;

[0013] The value range of s is 12.5mm. 2 ~65.4mm 2 .

[0014] The battery casing provided in this application has a stepped portion recessed into the casing cavity, and a seal is disposed on the stepped portion to block the liquid injection hole. Simultaneously, controlling the value range of a×b×s within the range of 1.5~45 balances the welding quality between the seal and the casing body, as well as the flatness of the casing body's opening side (the surface where the liquid injection hole is located). That is, while ensuring the welding quality between the seal and the casing body, the flatness of the casing body's opening side is also guaranteed. This prevents the seal from being too thick or too large, causing it to protrude from the casing surface and resulting in poor surface flatness, or the seal from being too thin or too small, leading to poor welding quality and a poor sealing effect.

[0015] A second aspect of this application provides a battery cell including a battery casing as described in any of the preceding claims.

[0016] The battery cell provided in this application has all the technical effects of the aforementioned battery casing, which will not be elaborated further here.

[0017] A third aspect of this application provides a battery pack comprising battery cells as described in any of the preceding claims.

[0018] The battery pack provided in this application has all the technical effects of the aforementioned battery cells, and will not be described in detail here.

[0019] A fourth aspect of this application provides an electrical device including a battery pack as described above.

[0020] The electrical equipment provided in this application has the aforementioned battery pack, and therefore possesses all the technical effects of the aforementioned battery pack, which will not be elaborated upon here. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is an exploded view of a single battery cell disclosed in an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of the structure of the housing body on the opening side of the housing body as disclosed in the embodiments of this application;

[0024] Figure 3 This is a cross-sectional view of a battery cell disclosed in an embodiment of this application;

[0025] Figure 4 This is a cross-sectional view of a battery cell disclosed in an embodiment of this application on the side with the opening in the casing;

[0026] Figure 5 This is a partial enlarged view of the battery cell at the location of the seal in the embodiments of this application;

[0027] Figure 6 This is a partial enlarged view of the housing body at the injection hole disclosed in the embodiments of this application.

[0028] The meanings of the various reference numerals in the figure are as follows:

[0029] 100 - Housing body; 101 - Injection hole; 1011 - Stepped portion; 1012 - Insertion portion;

[0030] 200 - Seals;

[0031] 300 - Sealing body;

[0032] 400 - Battery cell; 401 - Core hole. Detailed Implementation

[0033] This application discloses a battery casing that ensures both welding quality and flatness of the casing.

[0034] This application also discloses a battery cell, a battery pack, and an electrical device having the above-described battery casing.

[0035] Hereinafter, embodiments will be described with reference to the accompanying drawings. Furthermore, the embodiments shown below do not limit the scope of the application as described in the claims. Additionally, the complete content of the structures represented in the embodiments below is not limited to those necessary for the solution of the application as described in the claims. It should be noted that, for ease of description, only the parts relevant to the application are shown in the drawings. Unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0036] As vehicles age, the demands for extended driving range increase, leading to greater requirements for lightweight batteries. Therefore, titanium casings are currently being used for battery design. Titanium forms a dense oxide film in many environments, effectively preventing further oxidation and corrosion. This allows titanium-cased batteries to withstand harsh chemical environments, such as those containing acids or alkalis, exhibiting significantly higher stability than batteries with casings made of other materials, reducing performance degradation and safety hazards caused by casing corrosion.

[0037] Titanium has a high strength-to-weight ratio, meaning that while ensuring the battery casing has sufficient strength to protect the internal cells, the overall weight of the battery can be reduced. For weight-sensitive applications such as aerospace and electric vehicles, reducing battery weight helps improve energy efficiency and increase driving range.

[0038] The injection port needs to be sealed with a seal. If the seal is welded directly to the outer surface of the battery casing, it will protrude beyond the outer surface of the battery casing, affecting the flatness of the battery casing. Therefore, in the prior art, a recessed step is usually provided at the location of the injection port, pointing inwards towards the cavity of the battery casing. The seal is fixed on the step to prevent it from protruding beyond the outer surface of the battery casing and to ensure the flatness of the battery casing.

[0039] However, the higher the titanium content, the greater the hardness of the battery casing. Excessive hardness will affect the processing of the stepped part, and the depth of the stepped part will affect the welding quality of the seal. In order to ensure the welding quality, the seal may protrude from the outer surface of the battery casing.

[0040] Based on this, embodiments of this application disclose a battery casing that ensures both welding quality and flatness of the casing. For example... Figure 1 and Figure 2 As shown in the embodiments of this application, the battery casing disclosed includes a casing body 100 and a sealing element 200.

[0041] The housing body 100 includes a main housing portion and a cover plate. The housing body 100 is used to encapsulate components such as the battery cell and electrolyte. The main housing portion can have various shapes and sizes, such as cuboid, cylindrical, and hexagonal prism. The shape of the main housing portion can be determined according to the specific shape and size of the battery cell. The material of the main housing portion can be various, including but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0042] A cover is a component that closes onto an opening in the main body of a housing to isolate the accommodating space from the external environment. The shape of the cover can be adapted to fit the shape of the main body of the housing. The cover can be made of a material with a certain degree of hardness and strength (such as aluminum alloy).

[0043] The casing 100 is the outer protective structure of the battery cell, serving to house and protect internal components (such as the battery cell 400). Figure 4 (As shown). The main function of the housing 100 is to prevent harmful substances such as moisture and oxygen from entering the interior, avoid damage to the battery cell 400, protect the battery cell 400 and other components from external physical impacts and chemical corrosion, and ensure the safety and stability of the battery cell.

[0044] Cell 400 is the smallest charge / discharge unit. Cell 400 is formed by winding or stacking a positive electrode sheet, a negative electrode sheet, and a separator between them. The positive electrode sheet includes a positive current collector and a positive active material. The positive current collector can be made of metals such as aluminum foil, nickel foil, or stainless steel, or a composite foil formed by combining metals and insulating materials. The positive active material includes the main positive active material, conductive agent, and binder. The main positive active material includes one or more lithium-containing positive active materials such as lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate.

[0045] Similarly, the negative electrode sheet includes a negative current collector and a negative active material. The negative current collector can be made of metal materials such as copper foil, aluminum foil, and stainless steel, or it can be a composite foil formed by combining metals and insulating materials. The negative active material includes a negative active material, a conductive agent, and a binder. The negative active material includes one or more of the following: artificial graphite, natural graphite, silicon carbide, silicon oxide, and lithium titanate. The battery cell 400 has a battery cell output terminal, which is generally a tab assembly. Depending on the polarity, the tab assembly generally includes a positive tab assembly and a negative tab assembly. The positive tab assembly is electrically connected to the positive output terminal on the housing body 100, and the negative tab assembly is electrically connected to the negative output terminal on the housing body 100. The positive tab assembly and the positive electrode sheet are either integrally connected or separately connected, and the negative tab assembly and the negative electrode sheet are either integrally connected or separately connected. The separator, as an insulating layer, is used to prevent short circuits inside the battery cell caused by contact between the positive and negative electrodes. As a semi-permeable layer, the separator prevents larger molecules from passing through while allowing smaller charged ions to pass through.

[0046] The titanium content in the shell body 100 is 'a', and the shell body 100 is provided with a stepped portion 1011 that is recessed towards the shell cavity of the shell body 100. The stepped portion 1011 is provided with an injection hole 101, which connects to the shell cavity of the shell body 100. For ease of understanding, the side of the shell body 100 with the injection hole 101 is defined as the shell opening side. The shape of the stepped portion 1011 can be any shape, such as polygonal, circular, or elliptical, and the channel of the injection hole 101 can also be polygonal, circular, or elliptical. The covering area of ​​the stepped portion 1011 is larger than the cross-sectional area of ​​the channel, so that after the sealing member 200 is fixed inside the stepped portion 1011, it can completely cover the channel of the injection hole 101, thereby achieving a sealing effect on the channel of the injection hole 101. The shape of the channel of the injection hole 101 and the stepped portion 1011 can be designed as similar shapes for ease of processing.

[0047] like Figure 5 As shown, the sealing element 200 is disposed on the stepped portion 1011 to block the channel of the injection hole 101. The thickness of the sealing element 200 is b1, and the thickness of the housing opening side (i.e., the housing wall thickness on the side of the housing body 100 where the injection hole 101 is disposed) is b2. It should be noted that b1 and b2 need to use the same unit, for example, both units are mm.

[0048] Let b1 / b2 be b, that is, b1 / b2 = b. Since b1 and b2 have the same unit, their units cancel each other out when divided, so b is a constant. The area of ​​seal 200 is s, in mm. 2 Therefore, the range of values ​​for a×b×s is 1.5 to 45. It should be noted that a×b×s is a unitless value.

[0049] For example, the specific values ​​of a×b×s can be 1.5, 3, 4.5, 6, 7.5, 9, 10.5, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, etc. This embodiment does not limit the specific values ​​of a×b×s, and those skilled in the art can choose according to their needs.

[0050] The battery cell disclosed in this application has a liquid injection hole 101 including a stepped portion 1011 recessed into the cavity of the housing body 100, and a sealing member 200 is disposed within the stepped portion 1011 to seal the liquid injection hole 101. Simultaneously, by controlling the values ​​of a×b×s within the range of 1.5 to 45, a balance can be struck between the welding quality of the sealing member 200 and the housing body 100, and the flatness of the housing opening side of the housing body 100. That is, while ensuring the welding quality of the sealing member 200 and the housing body 100, the flatness of the housing opening side of the housing body 100 is improved.

[0051] The battery casing disclosed in this application has a stepped portion 1011 recessed into the casing cavity of the casing body 100, and a sealing member 200 is disposed on the stepped portion 1011 to seal the liquid injection hole. Simultaneously, by controlling the value range of a×b×s within the range of 1.5~45, a balance can be struck between the welding quality of the sealing member 200 and the casing body 100, and the flatness of the casing opening side (the side surface where the liquid injection hole is located) of the casing body 100. That is, while ensuring the welding quality of the sealing member 200 and the casing body 100, the flatness of the casing opening side of the casing body 100 is also guaranteed. This prevents the sealing member 200 from being too thick or having too large an area, causing it to protrude from the casing surface and resulting in poor surface flatness. This can also prevent the value of a×b×s from being too small, the thickness of the seal 200 from being too thin, and the area from being too small, which would result in poor welding quality between the seal 200 and the housing body 100 and thus poor sealing effect.

[0052] Those skilled in the art will understand that the higher the titanium content of the shell body 100, the greater the shell hardness. Materials with higher hardness also have higher melting points, requiring higher energy input for melting during welding. Therefore, a higher titanium content in the shell body 100 increases the welding difficulty. Conversely, a lower titanium content in the shell body 100 prevents it from meeting lightweight requirements.

[0053] Based on this, in a specific embodiment of this application, the value of 'a' ranges from 70% to 99.7%. That is, the titanium content of the shell body 100 can be in the range of 70% to 99.7%, which can take into account both the requirements of lightweighting and welding difficulty. This can prevent the welding difficulty caused by an excessively large value of 'a', and also prevent the lightweighting problem caused by an excessively small value of 'a'.

[0054] For example, 'a' can be 70%, 75%, 80%, 85%, 90%, 95%, 98.5%, 98.8%, 99%, 99.2%, 99.4%, 99.5%, 99.6%, 99.7%, etc. In this embodiment, the specific value of 'a', that is, the titanium content of the shell body 100, is not limited. Those skilled in the art can select it according to their needs.

[0055] In a specific embodiment of this application, the value of b ranges from 0.13 to 1.33. That is, the ratio of the thickness b1 of the seal 200 to the thickness b2 of the housing opening side is controlled within the range of 0.13 to 1.33. When b is within the range of 0.13 to 1.33, the requirements for the flatness of the housing opening side of the housing body 100 and the welding quality can be balanced, ensuring both the flatness of the housing opening side and the welding quality.

[0056] For example, b can be 0.13, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.33, etc. In this embodiment, the specific value of b, that is, the ratio of the thickness b1 of the seal 200 to the thickness b2 of the opening side of the housing, is not limited. Those skilled in the art can select according to their needs.

[0057] In a specific embodiment of this application, the value range of s is 12.5mm. 2 ~65.4mm 2 The area of ​​the sealing element 200 is controlled to be 12.5mm². 2 ~65.4mm 2 Within the range. s is within 12.5mm. 2 ~65.4mm 2 Within the specified range, the requirements for the flatness of the shell opening side and the welding quality of the shell body 100 can be taken into account, ensuring both the flatness of the shell opening side and the welding quality.

[0058] For example, s can be 12.5mm 2 15mm 2 17.5mm 2 20mm 2 22.5mm 2 25mm 2 27.5mm 2 30mm 2 32.5mm 2 35mm 2 37.5mm 2 40mm 2 42.5mm 2 45mm 2 47.5mm 2 50mm 2 52.5mm 2 55mm 2 57.5mm 2 60mm 2 62.5mm 2 65mm 2 65.4mm 2 In this embodiment, the specific value of s, that is, the area of ​​the sealing element 200, is not limited. Those skilled in the art can choose according to their needs.

[0059] For ease of understanding, the surface of the seal 200 facing the outside of the housing body 100 (i.e., the surface away from the housing cavity) is defined as the outer surface of the nail head. The outside of the housing body 100 is the side of the housing body 100 facing away from the battery cell 400 (i.e., the side away from the housing cavity). In this embodiment, the outer surface of the nail head can be designed to be flush with the outer surface of the housing opening side. It should be noted that the outer surface of the nail head of the seal 200 can be on the same plane, or it can be designed so that different areas are on different planes, making the outer surface of the nail head stepped. When the outer surfaces of the nail heads are not on the same plane, the outer surface of the nail head being flush with the outer surface of the housing opening side means that the minimum distance between the outer surface of the nail head and the outer surface of the housing opening side is 0, that is, the surface of the nail head farthest from the battery cell 400 is flush with the outer surface of the housing opening side.

[0060] This configuration allows for maximizing the thickness b1 of the seal 200, ensuring that the seal 200 does not protrude beyond the outer surface of the housing opening. This means that the seal 200 has a certain thickness, resulting in better welding quality between the seal 200 and the housing body 100. Based on this, the area of ​​the seal 200 can be designed to be smaller.

[0061] In this embodiment, when the outer surface of the nail head is designed to be flush with the outer surface of the housing opening side, the value range of s can be designed as: 12.5mm. 2 ~48.9mm 2 For example, s can be 12.5 mm. 2 14 mm 2 16.5 mm 2 19 mm 2 21.5 mm 2 24 mm 2 26.5 mm 2 29 mm 2 31.5 mm 2 34 mm 2 36.5 mm 2 39 mm 2 41.5 mm 2 44 mm 2 46.5 mm 2 48.9 mm 2 In this embodiment, the upper limit of s can be reduced so that the area of ​​the seal 200 can be within a smaller range, which can still meet the usage requirements.

[0062] In another embodiment of this application, the outer surface of the nail head can be designed to be closer to the battery cell 400 inside the housing body 100 (i.e. closer to the housing cavity) than the outer surface of the housing opening side. Taking the liquid injection hole 101 being located at the bottom of the housing body 100 as an example, when the outer surface of the nail head is closer to the battery cell 400 inside the housing body 100 than the outer surface of the housing opening side, it means that the outer surface of the nail head is located above the bottom plane of the housing body 100 (i.e. the outer surface of the housing opening side).

[0063] That is, along the height direction of the housing body 100 (when the housing body 100 is a cylindrical structure, the height direction of the housing body 100 is the axial direction of the housing body 100), the surface of the sealing element 200 away from the housing cavity is higher than the surface of the housing opening side of the housing body 100 away from the housing cavity, and the housing opening side is the side of the housing body 100 where the injection hole 101 is provided.

[0064] With this configuration, while ensuring that the seal 200 does not protrude from the outer surface of the opening side of the housing, the thickness b1 of the seal 200 is not maximized. That is, when the depth of the step portion 1011 is constant, the thickness of the seal 200 is thinner than in the previous embodiment, resulting in a lower welding quality between the seal 200 and the housing body 100 compared to the previous embodiment. Based on this, the area of ​​the seal 200 can be designed to be larger to compensate for the poor sealing effect caused by the insufficient thickness of the seal 200.

[0065] In this embodiment, when the outer surface of the nail head is designed to be closer to the outer surface of the housing opening than the outer surface of the cell 400, the value range of s can be designed as: 45.6 mm. 2 ~65.4 mm 2 In this embodiment, the lower limit of s can be increased so that the area of ​​the seal 200 can be within a larger range to compensate for the poor sealing effect caused by insufficient thickness.

[0066] For example, s can be 45.6 mm 2 47.6 mm 2 50.6 mm 2 53.6 mm 2 56.6 mm 2 58.6 mm 2 60.6 mm 2 62.6 mm 2 64 mm 2 65.4 mm 2 In this embodiment, the specific value of s, that is, the area of ​​the sealing element 200, is not limited. Those skilled in the art can choose according to their needs.

[0067] like Figure 5As shown, specifically, the distance between the outer surface of the nail head and the outer surface of the housing opening side is L. That is, in the height direction of the housing body 100, the distance between the surface of the sealing member 200 away from the housing cavity and the surface of the housing opening side away from the housing cavity is L, then L≤0.15mm. For example, the distance L between the outer surface of the nail head and the outer surface of the housing opening side can be 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.10mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, etc. This embodiment does not limit the specific value of L, and those skilled in the art can select it according to their needs.

[0068] like Figure 5 As shown in a specific embodiment of this application, the battery cell may further include a sealing body 300 inserted into the channel of the electrolyte injection hole 101, and the sealing member 200 is located further away from the housing cavity of the housing body 100 than the sealing body 300. The sealing body 300 is the first seal for the electrolyte injection hole 101, while the sealing member 200 is the second seal for the electrolyte injection hole 101. By providing two seals, the sealing effect of the electrolyte injection hole 101 can be further improved, preventing electrolyte leakage.

[0069] The sealing body 300 can be made of rubber (such as nitrile rubber, fluororubber, etc.), plastic (polypropylene, polytetrafluoroethylene, etc.), silicone, etc. Nitrile rubber has excellent oil resistance and good resistance to electrolytes, and is not easily corroded or swollen. It also possesses good elasticity and sealing performance, allowing it to tightly fit the injection hole 101 and prevent electrolyte leakage. Fluororubber has excellent high-temperature resistance and chemical corrosion resistance, able to withstand high temperatures and highly corrosive electrolytes, maintaining good sealing performance and physical properties even at high temperatures. Polypropylene is lightweight and low-cost, with good chemical stability and some resistance to common electrolytes. Its good molding and processing performance allows it to be made into seals of various shapes and sizes to meet the sealing requirements of different injection holes. Polytetrafluoroethylene has extremely excellent chemical stability and excellent corrosion resistance to electrolytes. It also has a low coefficient of friction, a smooth surface, is easy to install, and has outstanding high-temperature resistance. Silicone rubber has good high and low temperature resistance, maintaining elasticity and sealing performance over a wide temperature range. Those skilled in the art can select the material of the sealing body 300 according to their needs.

[0070] In this embodiment, the addition of the sealing body 300 gives the injection hole 101 two seals, improving the sealing effect of the injection hole 101. Therefore, the value of b can be designed to be smaller, while still meeting the sealing requirements.

[0071] In a specific embodiment of this application, the value of b ranges from 0.13 to 0.56, meaning the ratio of the thickness b1 of the seal 200 to the thickness b2 of the opening side of the housing is controlled within the range of 0.13 to 0.56. For example, b can be 0.13, 0.18, 0.23, 0.35, 0.38, 0.4, 0.43, 0.47, 0.5, 0.52, 0.54, 0.56, etc. That is, in this embodiment, the upper limit of b can be reduced, allowing the thickness of the seal 200 to be within a smaller range while still meeting usage requirements. While meeting sealing requirements, reducing the thickness of the seal 200 can lower processing costs and reduce the probability of the seal 200 protruding beyond the outer surface of the opening side of the housing.

[0072] A battery cell 400 is disposed within the housing body 100. The battery cell 400 has a winding hole 401, which is located at the center of the battery cell winding structure. In a cylindrical battery cell, the winding hole 401 is located at the axis of the entire battery cell 400; in a square battery cell, the winding hole is also located in the central area of ​​the winding section. The shape can vary depending on design requirements, commonly including a racetrack shape or a near-square through-structure. The battery cell 400 generates heat during charging and discharging, and good heat dissipation is crucial for maintaining the performance and safety of the battery cell 400. The winding hole 401 can assist in heat dissipation to some extent; air or other media can flow within the winding hole 401, carrying away some heat and reducing the temperature gradient inside the battery cell 400.

[0073] In one specific embodiment of this application, the injection hole 101 includes an insertion portion 1012 extending into the core hole 401. It should be noted that the cavity of the insertion portion 1012 can be understood as the channel of the injection hole 101. When a sealing body 300 is provided, the sealing body 300 can be inserted into the cavity of the insertion portion 1012 to seal the cavity of the insertion portion 1012. The sealing member 200 is farther from the battery cell 400 than the sealing body 300.

[0074] Since the insertion part 1012 extends into the core hole 401, it can guide the electrolyte into the core hole 401 when electrolyte is injected into the injection hole 101, making leakage during the electrolyte injection process less likely. Therefore, the value of b can be smaller. In this embodiment, the upper limit of b can be further reduced based on the previous embodiment. Specifically, the value range of b can be 0.13~0.45, so that the thickness of the seal 200 can be within a smaller range, which can also meet the usage requirements.

[0075] like Figure 6 As shown, the stepped portion 1011 and the insertion portion 1012 are formed by a stamping process from the housing opening side of the housing body 100, and the axial overlap dimension of the insertion portion 1012 and the core hole 401 is h.

[0076] In this embodiment, the height h of the insertion part 1012 can be in the range of 0.4mm to 2mm. When h is in the range of 0.4mm to 2mm, it can take into account both the requirements of the flatness of the shell opening side and the risk of electrolyte leakage. It can facilitate the injection of electrolyte into the core hole 401 and prevent leakage during the injection of electrolyte, while ensuring the flatness of the shell opening side without increasing the stamping difficulty.

[0077] For example, h can be 0.4mm, 0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, etc. In this embodiment, the specific value of h, that is, the overlap dimension of the insertion part 1012 and the core hole 401 in the axial direction, is not limited. Those skilled in the art can select according to their needs.

[0078] The stepped portion 1011 and the insertion portion 1012 can be arranged coaxially. The stepped portion 1011 and the insertion portion 1012 can be stamped simultaneously or sequentially using a mold.

[0079] like Figure 4 As shown, along the radial direction of the seal 200, the edge of the seal 200 extends beyond the edge of the orifice of the injection hole 101. The orifice of the injection hole 101 is the opening of the orifice of the injection hole 101 located on the stepped portion 1011. The edge of the seal 200 needs to extend beyond the orifice of the injection hole 101 to achieve a seal on the orifice of the injection hole 101.

[0080] In this embodiment, the dimension by which the edge of the sealing element 200 extends beyond the edge of the injection hole 101 is within the range of 1mm to 4mm, ensuring that the sealing element 200 completely covers the opening of the injection hole 101. The dimension by which the edge of the sealing element 200 extends beyond the edge of the injection hole 101 can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, etc. This embodiment does not limit the specific dimension by which the edge of the sealing element 200 extends beyond the edge of the injection hole 101; those skilled in the art can select according to their needs.

[0081] The seal 200 includes a welding area welded to the housing body 100, meaning the seal 200 is welded to the housing body 100, and the area where the seal 200 is welded to the housing body 100 is the welding area. The stepped portion 1011 includes a bottom wall portion and a side wall portion surrounding the bottom wall portion. The bottom wall portion of the stepped portion 1011 may be parallel to the surface of the housing body 100 on the side of the housing opening. The injection hole 101 is used to inject electrolyte into the cavity of the housing body 100. The injection hole 101 may be a channel directly formed on the bottom wall portion of the stepped portion 1011, or it may be an insertion portion 1012 extending from the bottom wall portion of the stepped portion 1011 into the core hole 401.

[0082] In this embodiment, the welding area is located on the contact surface between the seal 200 and the bottom wall of the step portion 1011, that is, the plate surface of the seal 200 facing the bottom wall of the step portion 1011 is welded to the bottom wall. Therefore, the seal 200 and the step portion 1011 need to be welded using penetration welding. Penetration welding mainly relies on a high-energy-density welding heat source, such as a laser beam or electron beam, to rapidly heat the seal 200 to a molten state, allowing the weld metal to penetrate the thickness of the seal 200. Taking laser penetration welding as an example, a high-energy laser beam is focused on the surface of the seal 200, instantly generating extremely high temperatures, causing the surface material of the seal 200 to rapidly melt and form a molten pool. As the laser beam moves, the molten pool continuously advances and penetrates the seal 200. After the molten pool cools and solidifies, a weld that penetrates the thickness of the seal 200 is formed.

[0083] When the seal 200 and the step portion 1011 are connected by through-weld, in order to ensure welding quality, the value of b needs to be larger, that is, the thickness of the seal 200 needs to be larger to ensure the sealing effect of the seal 200 on the injection hole 101. In this embodiment, the value of b can be in the range of 0.6 to 1.33. For example, b can be 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.33, etc. That is, in this embodiment, the lower limit of b can be increased so that the thickness of the seal 200 can be within a larger range to ensure welding quality.

[0084] In another embodiment of this application, the welding area is at least partially located on the outer edge of the seal 200 facing the sidewall portion, that is, the outer surface of the seal 200 is welded to the sidewall portion of the step portion 1011. Therefore, the seal 200 and the step portion 1011 need to be butt-welded. Butt-welding utilizes the resistance heat generated when current passes through the seal 200 and the step portion 1011 as a heat source, causing the surfaces of the mating seal 200 and the step portion 1011 to heat up rapidly. During the welding process, the resistance on the contact surface of the seal 200 and the step portion 1011 converts electrical energy into heat energy, causing the metal in that area to reach a plastic or molten state. As heating progresses, the metal at the mating surfaces gradually fuses together, firmly bonding the two metal parts together to form a dense weld.

[0085] When the seal 200 and the step portion 1011 are butt-welded, the area of ​​the seal 200 needs to be larger to ensure welding quality. In this embodiment, the value of s can be 45 mm. 2 ~65.4 mm 2In this embodiment, the lower limit of s can be increased so that the area of ​​the seal 200 can be within a larger range, so that the seal 200 can fit or approach the side wall of the step portion 1011, ensuring that welding can be completed.

[0086] For example, s can be 45 mm 2 46.5 mm 2 47.6 mm 2 48.9 mm 2 50.6 mm 2 51.7 mm 2 53.6 mm 2 55.3 mm 2 56.6 mm 2 58.6 mm 2 60.6 mm 2 61.4 mm 2 62.6 mm 2 63.4 mm 2 64 mm 2 64.8 mm 2 65.4 mm 2 In this embodiment, the specific value of s, that is, the area of ​​the sealing element 200, is not limited. Those skilled in the art can choose according to their needs.

[0087] In a specific embodiment of this application, the minimum distance from the edge of the stepped portion 1011 to the edge of the housing opening side along the radial direction of the stepped portion 1011 can range from 3mm to 21.5mm. The edge of the stepped portion 1011 is the location of the sidewall portion of the stepped portion 1011. Taking a cylindrical battery cell as an example, the housing opening side can be one of the end faces of the housing body 100, which is also a circular structure. The liquid injection hole 101 can also be circular. In this way, the edge of the stepped portion 1011 is the outermost ring of the liquid injection hole 101, and the edge of the housing opening side is the outer ring of the end face of the housing body 100.

[0088] In this embodiment, the minimum distance from the edge of the stepped portion 1011 to the edge of the shell opening side is designed to be 3mm~21.5mm. Given a fixed size for the shell opening side, a balance can be achieved between electrolyte injection and the strength of the shell opening side. This facilitates electrolyte injection while ensuring the strength of the shell opening side.

[0089] The minimum distance from the edge of the stepped portion 1011 to the edge of the housing opening side can be: 3mm, 5mm, 7mm, 9mm, 11mm, 13mm, 15mm, 17mm, 19mm, 20mm, 21mm, 21.5mm, etc. This embodiment does not limit the minimum distance from the edge of the stepped portion 1011 to the edge of the housing opening side; those skilled in the art can select according to their needs.

[0090] In a specific embodiment of this application, the housing body 100 includes a housing body portion and a cover plate. At least one end of the housing body portion has an opening for assembling a battery cell 400. The battery cell 400 is inserted into the cavity of the housing body portion through the opening. After the battery cell 400 and other components are assembled, the cover plate is fixed to the housing body portion to seal the opening of the housing body portion.

[0091] The thickness of the cover plate is usually greater than the thickness of the main body of the housing. When the injection hole 101 is located in the main body of the housing, since the main body of the housing is thinner, the injection hole 101 is easier to stamp and form on the main body of the housing. Therefore, the depth of the step portion 1011 is easier to ensure. In order to ensure better welding quality, the value of b can be larger, that is, the thickness of the seal 200 can be increased to ensure the sealing effect of the seal 200 on the injection hole 101.

[0092] In this embodiment, the value of b can range from 0.65 to 1.33. For example, b can be 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.33, etc. That is, in this embodiment, the lower limit of b can be increased so that the thickness of the sealing element 200 can be within a larger range to ensure the sealing effect of the sealing element 200 on the injection hole 101.

[0093] When the injection hole 101 is located on the cover plate, the injection hole 101 is difficult to be stamped on the cover plate due to the thickness of the cover plate. Therefore, the depth of the step 1011 is not easy to guarantee, resulting in insufficient depth of the step 1011. In order to ensure that the seal 200 does not protrude from the outer surface of the opening side of the housing, the value of b needs to be smaller, that is, the thickness of the seal 200 needs to be reduced to avoid the seal 200 protruding from the outer surface of the opening side of the housing and to ensure the flatness of the opening side of the housing.

[0094] In this embodiment, the value of b can range from 0.13 to 0.62, meaning the ratio of the thickness b1 of the seal 200 to the thickness b2 of the opening side of the housing is controlled within the range of 0.13 to 0.62. For example, b can be 0.13, 0.18, 0.23, 0.35, 0.38, 0.4, 0.43, 0.47, 0.5, 0.52, 0.54, 0.56, 0.6, 0.62, etc. In other words, in this embodiment, the upper limit of b can be reduced, allowing the thickness of the seal 200 to be within a smaller range. While meeting the sealing requirements, reducing the thickness of the seal 200 can lower processing costs, prevent the seal 200 from protruding beyond the outer surface of the opening side of the housing, and ensure the flatness of the opening side of the housing.

[0095] In a specific embodiment of this application, when the housing body 100 is a cylindrical structure, the injection hole 101 is located at the center of the opening side of the housing. If the cross-section of the injection hole 101 is circular, that is, the injection hole 101 is coaxially arranged with the housing body 100. Since the injection hole 101 is located at the center of the opening side of the housing, the force is more uniform during the stamping process, making the injection hole 101 easier to form and ensuring the depth of the step portion 1011. To ensure better welding quality, the value of b can be larger, that is, the thickness of the sealing element 200 can be increased to ensure the sealing effect of the sealing element 200 on the injection hole 101.

[0096] In this embodiment, the value of b can range from 0.5 to 1.33. For example, b can be 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.33, etc. That is, in this embodiment, the lower limit of b can be increased so that the thickness of the seal 200 can be within a larger range to ensure welding quality.

[0097] In another specific embodiment of this application, the housing body 100 has a cuboid structure, and the injection hole 101 is offset at the center of the housing opening side (i.e., one side surface of the housing body 100). The housing opening side has a rectangular structure, and the injection hole 101 is usually not located at the center of the housing opening side, but rather on one side. When stamping the injection hole 101, due to the offset setting of the injection hole 101, if the step portion 1011 has sufficient depth and cross-sectional area during stamping, a sufficiently large stamping force is required, which can easily cause deformation of the housing opening side, affecting the flatness of the housing opening side. To prevent deformation of the housing opening side during stamping, it is usually necessary to reduce the depth and cross-sectional area of ​​the step portion 1011.

[0098] Based on this, in this embodiment, the value of b can be smaller, that is, the thickness of the seal 200 is reduced, so as to ensure that the seal 200 does not protrude from the outer surface of the opening side of the housing, and to ensure the flatness of the opening side of the housing.

[0099] In this embodiment, the value of b can be in the range of 0.13-0.5, that is, the ratio of the thickness b1 of the seal 200 to the thickness b2 of the opening side of the housing is controlled within the range of 0.13 to 0.5. For example, b can be 0.13, 0.15, 0.18, 0.2, 0.23, 0.30, 0.35, 0.38, 0.4, 0.43, 0.47, 0.5, etc. That is, in this embodiment, the upper limit of b can be reduced so that the thickness of the seal 200 can be taken within a smaller range. Under the premise of meeting the sealing requirements, reducing the thickness of the seal 200 can reduce the processing cost, prevent the seal 200 from protruding from the outer surface of the opening side of the housing, and ensure the flatness of the opening side of the housing.

[0100] In addition to titanium, the material of the housing body 100 may also include at least one of aluminum, vanadium, tin, and molybdenum. That is, in this embodiment, the material of the housing body 100 is a titanium alloy. Using titanium alloy as the material of the housing body 100 can reduce costs and improve welding strength.

[0101] In a specific embodiment of this application, the material of the seal 200 can be titanium or a titanium alloy. Titanium alloys are mainly divided into three categories: 1. α-type titanium alloys (such as TA2), containing α-stabilizing elements such as aluminum, suitable for extreme temperature environments; 2. β-type titanium alloys (such as Ti-15-3), containing β-stabilizing elements such as molybdenum, with excellent high-temperature strength; 3. α+β type titanium alloys (such as Ti-6Al-4V), with balanced comprehensive performance, accounting for more than 70% of the titanium used in aerospace.

[0102] When the material of the seal 200 is titanium or titanium alloy, the seal 200 has high hardness and high welding melting point. In order to facilitate welding, the value of b can be smaller, that is, the thickness of the seal 200 needs to be reduced to prevent the thickness of the seal 200 from being too large, which would be not conducive to welding.

[0103] In this embodiment, the value of b can be in the range of 0.13-0.45, that is, the ratio of the thickness b1 of the seal 200 to the thickness b2 of the opening side of the housing is controlled within the range of 0.13 to 0.45. For example, b can be 0.13, 0.15, 0.18, 0.2, 0.23, 0.30, 0.35, 0.38, 0.4, 0.43, 0.45, etc. In other words, in this embodiment, the upper limit of b can be reduced so that the thickness of the seal 200 can be taken within a smaller range. This reduces the thickness of the seal 200, thus balancing the welding difficulties caused by the high hardness and high welding melting point of the seal 200.

[0104] In one specific embodiment of this application, the material of the seal 200 can be aluminum or an aluminum alloy. Aluminum alloys include, but are not limited to, cast aluminum alloys, wrought aluminum alloys, and aluminum-based composite materials. When the material of the seal 200 is aluminum or an aluminum alloy, the seal 200 has relatively low hardness and a relatively low welding melting point, making it easier to weld the seal 200 onto the housing body 100. Therefore, to ensure the sealing effect, the value of b can be larger, i.e., the thickness of the seal 200 can be increased to ensure the sealing effect of the seal 200 on the injection hole 101.

[0105] In this embodiment, the value of b can range from 0.5 to 1.33. For example, b can be 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.33, etc. That is, in this embodiment, the lower limit of b can be increased so that the thickness of the sealing element 200 can be within a larger range to ensure the sealing effect of the sealing element 200 on the injection hole 101.

[0106] Based on this, in a specific embodiment of this application, the thickness b1 of the sealing element 200 can be in the range of 0.1mm to 0.4mm. In this embodiment, controlling the thickness b1 within the range of 0.1mm to 0.4mm can balance the welding strength and the forming difficulty, ensuring welding strength while reducing forming difficulty.

[0107] For example, the thickness b1 of the seal 200 can be 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, etc. This embodiment does not limit the specific value of the thickness b1 of the seal 200, and those skilled in the art can select it according to their needs.

[0108] Those skilled in the art will understand that the shell opening side of the shell body 100 may be integrally stamped with the shell body 100, or the shell opening side of the shell body 100 may be stamped separately from the main body of the shell body 100. When the shell opening side of the shell body 100 is integrally stamped with the shell body 100, the forming difficulty is relatively high, especially when the thickness b2 of the shell opening side (since the shell opening side and other parts of the shell body 100 are integral structures, the thickness is basically the same) is too large, it will further increase the forming difficulty of the shell body 100.

[0109] When the shell opening side of the shell body 100 and the main body of the shell body 100 are stamped and formed respectively, the shell opening side is the cover plate of the shell body 100. The structure of the cover plate is relatively complex. If the thickness b2 of the shell opening side is too large, it will also increase the forming difficulty of the shell opening side.

[0110] If the thickness b2 on the opening side of the housing is too small, although it is easier to form, it will affect the welding of the seal 200 on the opening side of the housing, and there is a risk of welding through the opening side of the housing during welding.

[0111] Based on this, in a specific embodiment of this application, the thickness b2 of the shell body 100 on the shell opening side can be in the range of 0.3mm to 0.8mm. In this embodiment, controlling the thickness b2 within the range of 0.3mm to 0.8mm can balance the welding strength and the forming difficulty.

[0112] For example, the thickness b2 on the opening side of the housing can be 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, etc. This embodiment does not limit the specific value of the thickness b2 on the opening side of the housing, and those skilled in the art can select it according to their needs.

[0113] This application also discloses a battery cell, including the battery casing disclosed in the above embodiments. The battery cell disclosed in this application, having the aforementioned battery casing, possesses all the technical effects of the aforementioned battery casing, which will not be elaborated upon here.

[0114] This application also discloses a battery pack, including the battery cells disclosed in the above embodiments. The battery pack disclosed in this application, having the aforementioned battery cells, possesses all the technical effects of those cells, which will not be repeated here. It should be noted that this battery pack can be used as a start-stop power supply and can also be used in other fields.

[0115] This application also discloses an electrical device that includes the battery pack disclosed in the above embodiments. This electrical device can be an electric vehicle, an electric ship, an aircraft, an energy storage device, etc. The electrical device disclosed in this application, having the aforementioned battery pack, possesses all the technical effects of the battery pack, which will not be elaborated upon further here.

[0116] The method for testing the titanium content in the battery casing is as follows:

[0117] (1) Sample preparation: First, the battery casing sample to be tested needs to be properly treated to facilitate X-ray penetration and excitation of fluorescence. The treatment methods may include cutting, grinding, polishing and other steps to ensure that the surface of the battery casing sample is flat and free of contamination.

[0118] (2) X-ray excitation: High-energy X-rays are used to irradiate the surface of the battery casing sample to excite the characteristic X-ray fluorescence of each element. The wavelength or energy characteristics of these fluorescence spectra correspond to the types of elements, thereby determining which elements are contained in the battery casing sample.

[0119] (3) Spectral collection and analysis: X-rays reflected from the surface of the battery casing sample and fluorescence spectra are collected using a spectrometer. The type and content of elements can be determined by the position and intensity of characteristic spectral lines.

[0120] (4) Matrix effect correction: Due to the interaction between various elements in the battery casing sample (matrix effect), the collected spectral data needs to be corrected to eliminate the influence of this interaction on the analysis results and improve the accuracy of the analysis.

[0121] (5) Interpretation of results: Based on the corrected data, the content of each element in the battery casing sample can be calculated, and then the proportion of the mass of Ti element in the battery casing sample to the total mass of the battery casing sample can be obtained, that is, the content of Ti element a.

[0122] To verify the technical effect of the battery casing disclosed in the embodiments of this application, flatness test and sealing effect test (such as melting depth and melting width test) were performed on the battery casing. The specific test methods are as follows, and the specific test results are detailed in Table 1.

[0123] Flatness test method: Place the side of the battery casing with the liquid injection hole (i.e. the casing opening side) on a marble surface, and then use a height gauge probe to measure the flatness of the casing opening side. Randomly select six points and record the height difference. The maximum value is the flatness. Flatness ≤ 0.15mm is qualified.

[0124] Sealing effect - Test method for weld depth and weld width: After welding the sealing parts, the battery casing is sealed with crystal glue, and then the weld lines to be measured are cut and polished. The weld depth and weld width are measured using a two-dimensional measuring instrument. The weld depth > 0.3mm and weld width > 0.5mm are considered qualified.

[0125] Table 1 Comparison of Battery Casing Flatness and Sealing Effect Tests

[0126]

[0127] In Examples 1-6, the titanium content *a*, the area *s* of the seal, and the ratio *b* of the seal thickness *b1* to the shell wall thickness *b2* on the side of the shell body where the injection hole is located all meet the specified ranges (*a* ranges from 70% to 99.7%; *s* ranges from 12.5 mm). 2 ~65.4 mm 2 When the value of b is in the range of 0.13 to 1.33, and a×b×s also meets the specified range (the range of a×b×s is 1.5 to 45), the flatness of the battery casing and the sealing effect reflected by the melting depth and melting width are both better.

[0128] In Examples 7-11, at least one of the following three parameters—the titanium content *a*, the area *s* of the seal, and the ratio *b* of the seal thickness *b1* to the shell wall thickness *b2* on the side of the shell body where the injection hole is located—is outside the specified range (*a* ranges from 70% to 99.7%; *s* ranges from 12.5 mm). 2 ~65.4 mm 2 The value of b ranges from 0.13 to 1.33, but a×b×s meets the specified range (the range of a×b×s is 1.5 to 45). The flatness of the battery casing and the sealing effect reflected by the melting depth and melting width also meet the requirements, but the overall ability of flatness and sealing effect is slightly worse than that of parameters and a×b×s, which both meet the specified range.

[0129] In Comparative Examples 1 and 2, at least one of the following three parameters—the titanium content *a*, the area *s* of the seal, and the ratio *b* of the seal thickness *b1* to the shell wall thickness *b2* on the side of the shell body where the injection hole is located—is outside the specified range (*a* ranges from 70% to 99.7%; *s* ranges from 12.5 mm). 2 ~65.4 mm 2 The value of b is in the range of 0.13 to 1.33, and a×b×s does not meet the range (the range of a×b×s is 1.5 to 45).

[0130] In Comparative Example 1, a exceeds the upper limit, b is below the lower limit, and a×b×s is below the lower limit. Therefore, the melting depth and melting width do not meet the requirements, resulting in poor sealing performance.

[0131] In Comparative Example 2, b exceeds the upper limit value, s exceeds the upper limit value, and a×b×s exceeds the upper limit value, so its flatness does not meet the requirements and its flatness is poor.

[0132] Comparative Examples 3 and 4 all satisfy the specified ranges for the following parameters: titanium content (a), sealing area (s), and the ratio of sealing thickness (b1) to the shell wall thickness (b2) on the side of the shell body with the injection hole. (a ranges from 70% to 99.7%; s ranges from 12.5 mm.)2 ~65.4 mm 2 The value of b is in the range of 0.13 to 1.33, and a×b×s does not meet the range (the range of a×b×s is 1.5 to 45).

[0133] In Comparative Example 3, a×b×s exceeded the upper limit, and its melt depth and melt width did not meet the requirements, and its flatness did not meet the requirements, resulting in poor flatness.

[0134] In Comparative Example 4, a×b×s is below the lower limit, and its melting depth and melting width do not meet the requirements, resulting in poor sealing performance.

[0135] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "a," and / or "the" are not specifically singular and may include the plural. Generally, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. An element defined by the phrase "comprising an..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes the element.

[0136] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0137] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0138] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A battery casing, characterized in that, include: The shell body (100) contains titanium with a content of a, and the shell body (100) is provided with a stepped portion (1011) that is recessed into the shell cavity of the shell body (100), and the stepped portion (1011) is provided with a liquid injection hole (101). A sealing element (200) is welded to the stepped portion (1011) using through-welding to seal the channel of the injection hole (101). The thickness of the sealing element (200) is b1 (mm). The wall thickness of the housing body (100) on the side where the injection hole (101) is located is b2 (mm). b1 / b2 is b. The area of ​​the sealing element (200) is s (mm²). 2 Then the value range of a×b×s is 1.5~45, and the material of the sealing element (200) is aluminum or aluminum alloy; The value range of 'a' is 70% to 99.7%. The value of b ranges from 0.6 to 1.33; The value range of s is 12.5mm. 2 ~65.4mm 2 .

2. The battery casing as described in claim 1, characterized in that, The surface of the seal (200) away from the housing cavity is flush with the surface of the housing body (100) on the side with the housing opening away from the housing cavity. The side with the housing opening is the side of the housing body (100) where the injection hole (101) is located. Therefore, the value range of s is 12.5 mm. 2 ~48.9mm 2 .

3. The battery casing as described in claim 1, characterized in that, Along the height direction of the housing body (100), the surface of the sealing element (200) away from the housing cavity is higher than the surface of the housing body (100) away from the housing cavity on the housing opening side, where the housing opening side is the side of the housing body (100) where the injection hole (101) is located. Therefore, the value range of s is 45.6 mm. 2 ~65.4 mm 2 .

4. The battery casing as described in claim 3, characterized in that, In the height direction of the housing body (100), the distance between the surface of the seal (200) away from the housing cavity and the surface of the housing opening away from the housing cavity is L, then L≤0.15mm.

5. The battery casing as described in claim 1, characterized in that, It also includes a sealing body (300) inserted into the channel of the injection hole (101), and the sealing element (200) is further away from the housing cavity than the sealing body (300).

6. The battery casing as described in claim 1, characterized in that, The housing body (100) is used to install the battery cell (400), the battery cell (400) having a core hole (401); the liquid injection hole (101) includes an insertion portion (1012) for extending into the core hole (401).

7. The battery casing as described in claim 6, characterized in that, The overlap dimension of the insertion part (1012) and the core hole (401) in the axial direction is h, and the value range of h is 0.4mm~2mm.

8. The battery casing as described in claim 6, characterized in that, The stepped portion (1011) and the insertion portion (1012) are arranged coaxially.

9. The battery casing as described in claim 8, characterized in that, It also includes a sealing body (300) inserted into the insertion part (1012), and the sealing member (200) is further away from the housing cavity than the sealing body (300).

10. The battery casing as claimed in claim 1, characterized in that, Along the radial direction of the seal (200), the dimension of the edge of the seal (200) extending beyond the edge of the injection hole (101) is in the range of 1mm to 4mm.

11. The battery casing as claimed in claim 10, characterized in that, The seal (200) includes a welded area welded to the housing body (100).

12. The battery casing as described in claim 11, characterized in that, The stepped portion (1011) includes a bottom wall portion and a side wall portion surrounding the bottom wall portion, and the injection hole (101) is disposed on the bottom wall portion; the welding area is located on the contact surface between the seal (200) and the bottom wall portion.

13. The battery casing as described in any one of claims 1-12, characterized in that, In the radial direction, the minimum distance between the edge of the stepped portion (1011) and the edge of the housing body (100) ranges from 3mm to 21.5mm.

14. The battery casing as described in any one of claims 1-12, characterized in that, The housing body (100) includes a housing main body and a cover plate. At least one end of the housing main body has an opening for assembling a battery cell (400), and the cover plate is disposed at the opening of the housing main body. The injection hole (101) is located in the main body of the shell, and the value of b is in the range of 0.65~1.

33.

15. The battery casing as described in any one of claims 1-12, characterized in that, The housing body (100) is a cylindrical structure, and the injection hole (101) is coaxially arranged with the housing body (100).

16. The battery casing as described in any one of claims 1-12, characterized in that, The housing body (100) has a cuboid structure, and the injection hole (101) is offset at the center of one side surface of the housing body (100).

17. The battery casing as described in any one of claims 1-12, characterized in that, The material of the housing body (100) also includes at least one of aluminum, vanadium, tin and molybdenum.

18. The battery casing as described in any one of claims 1-12, characterized in that, The thickness b1 of the sealing element (200) ranges from 0.1mm to 0.4mm. And / or, The wall thickness b2 of the housing body (100) on the side where the injection hole (101) is located ranges from 0.3mm to 0.8mm.

19. A single battery cell, characterized in that, Includes the battery casing as described in any one of claims 1-18.

20. A battery pack, characterized in that, Includes the battery cell as described in claim 19.

21. An electrical appliance, characterized in that, Includes the battery pack as described in claim 20.

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