Battery case, battery comprising case, and electric device comprising battery

Abstract

The present application relates to the technical field of batteries, and more specifically to a battery case, a battery comprising the case, and an electric device comprising the battery. The material of the case comprises steel, and the components of the steel include Ti, Nb and Cr. Based on the total mass of the steel, the mass percentage content of Cr is greater than or equal to 16 wt.%. The case comprises a side wall and an end wall integrally formed with the side wall. The case satisfies the following relational expression: 50≤(h / d) / (b+c)≤7000, wherein h is the height of the case, in mm; d is the thickness of the end wall, in mm; b is the mass percentage content of Ti based on the total mass of the steel, in wt.%; and c is the mass percentage content of Nb based on the total mass of the steel, in wt.%. In the present application, by controlling the relationship between the Ti and Nb contents and the height and end wall thickness of the case, the steel with such Ti and Nb contents can meet the deep‑drawing performance requirements of the battery case, and the formed case has good pressure-bearing capacity.

Description

A battery casing, a battery including the casing, and an electrical device thereof.

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411556207.7, filed on November 4, 2024, entitled "A Battery Housing, a Battery Including the Housing and an Electrical Device Thereof", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, specifically to a battery casing, a battery including the casing, and an electrical device thereof. Background Technology

[0004] With the increasing popularity of new energy vehicles, the power battery, as a core component of new energy vehicles, directly determines the vehicle's range, performance, and overall safety. Among these components, the battery casing, as an important part of the power battery, is related to various battery performance aspects such as safety, energy density, and lifespan. Therefore, the battery casing is required to be lightweight while possessing excellent mechanical properties.

[0005] Deep drawing of metals involves using stamping, ring forming, or metal die-cutting processes to deform sheet metal materials into cylindrical or box-shaped parts. Deep drawing offers high productivity and material utilization, provides dimensional accuracy and low surface roughness, and can manufacture thin-walled and complex parts that are difficult to form using other methods. With increasingly fierce price competition, deep drawing is now widely used for battery casings to reduce raw material and process costs, requiring the casing material to possess excellent tensile ductility.

[0006] Currently, stainless steel is widely used in products requiring deep drawing due to its high elongation, allowing for the forming of complex shapes with few defects, and its excellent work hardening ability. However, when stainless steel is used for deep drawing, its strength continuously increases due to work hardening, and stress concentration occurs locally, leading to fracture. Summary of the Invention

[0007] The purpose of this application is to overcome the shortcomings of the prior art in which steel is prone to fracture during deep drawing when used as the material for battery casing, and to provide a battery casing, a battery including the casing, and an electrical device thereof.

[0008] To achieve the above objectives, in a first aspect of this application, this application provides a battery casing, the casing being made of steel, the steel comprising Ti, Nb and Cr, wherein, based on the total mass of the steel, the mass percentage of Cr is ≥16 wt.%.

[0009] The housing includes end walls;

[0010] The shell satisfies the following relationship: 50≤(h / d) / (b+c)≤7000;

[0011] Where h is the height of the shell, in mm;

[0012] d represents the thickness of the end wall, in mm;

[0013] b represents the mass percentage of Ti based on the total mass of the steel, expressed in wt.%.

[0014] c represents the mass percentage of Nb based on the total mass of steel, expressed in wt.%.

[0015] As an optional implementation of this application, the shell satisfies the following relationship: 142≤(h / d) / (b+c)≤2000.

[0016] As an optional implementation of this application, the range of h is 20-300 mm.

[0017] As an optional embodiment of this application, the range of h is 50-270 mm.

[0018] As an optional implementation of this application, the range of d is 0.2-1.5 mm.

[0019] As an optional implementation of this application, the range of d is 0.5-1.0 mm.

[0020] As an optional embodiment of this application, the range of b+c is 0.2-0.8 wt.%.

[0021] As an optional embodiment of this application, the range of b+c is 0.25-0.5 wt.%.

[0022] As an optional embodiment of this application, the range of b is 0.05-0.2 wt.%.

[0023] As an optional embodiment of this application, the range of c is 0.17-0.5 wt.%.

[0024] As an optional embodiment of this application, the housing further includes a sidewall, and the housing also satisfies the following relationship: 0.5≤(f / d) / (b+c)≤5, where f is the thickness of the sidewall of the housing in mm.

[0025] As an optional implementation of this application, the range of f is 0.1-1.2 mm.

[0026] As an optional embodiment of this application, the range of d is 0.3-1.2 mm.

[0027] As an optional embodiment of this application, a pressure relief structure is provided on the end wall of one end of the housing.

[0028] As an optional implementation of this application, the pressure relief structure includes a weak part, and the shell also satisfies the following relationship: 0.004≤m×(b+c)≤0.12, where m is the residual thickness of the weak part in mm.

[0029] As an optional implementation of this application, the range of m is 0.01-0.5 mm.

[0030] As an optional embodiment of this application, the housing is provided with an end cap at the other end opposite to the end wall, the end cap is fixedly connected to the side wall, and the end wall or the end cap is provided with a through hole for setting the pole assembly.

[0031] As an optional implementation of this application, the through hole is provided on the end wall, and the housing also satisfies the following relationship: 0.005≤k / (b+c)≤0.5, where k is the ratio of the area of ​​the through hole to the area of ​​the end wall where the through hole is located.

[0032] As an optional implementation of this application, the range of k is 0.00125-0.1.

[0033] As an optional implementation of this application, the end wall is provided with a liquid injection hole, and the shell also satisfies the following relationship: 0.004≤z / (b+c)≤0.3, where z is the ratio of the area of ​​the liquid injection hole to the area of ​​the end wall.

[0034] As an optional implementation of this application, the range of z is 0.001-0.08.

[0035] As an optional embodiment of this application, the steel composition further includes C, Si, Mn, P, S and Fe.

[0036] In a second aspect of this application, a battery is provided, including a battery casing as described above.

[0037] In a third aspect, this application provides an electrical device including the battery described above.

[0038] The beneficial effects of this application are as follows:

[0039] This application controls the relationship between the content of Ti and Nb and the height and end wall thickness of the casing, so that the steel with the specified Ti and Nb content can meet the deep drawing processing performance of the battery casing, and the formed casing has good mechanical properties such as pressure resistance. Attached Figure Description

[0040] Figure 1 is a schematic diagram of the overall structure of the battery in Example 1;

[0041] Figure 2 is a schematic diagram of the overall structure of the battery in Example 1 from another perspective;

[0042] Figure 3 is a schematic diagram of the structure of the shell in Embodiment 33;

[0043] Figure 4 is a magnified view of part A in Figure 3;

[0044] Figure 5 is a schematic diagram of the structure of the shell in Embodiment 38;

[0045] Figure 6 is a schematic diagram of the overall structure of the battery in Example 45.

[0046] The markings in the diagram are explained as follows: 1-Shell, 11-End wall, 12-End cap, 13-Side wall, 2-Weak part, 3-Through hole, 4-Injection hole, 5-Electrode assembly. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0048] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0049] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0050] One embodiment of this application provides a battery casing. The casing 1 is made of steel, and the steel composition includes Ti, Nb and Cr, wherein, based on the total mass of the steel, the mass percentage of Cr is ≥16 wt.%.

[0051] The housing 1 includes an end wall 11;

[0052] The shell 1 satisfies the following relationship: 50≤(h / d) / (b+c)≤7000;

[0053] Where h is the height of shell 1, in mm;

[0054] d is the thickness of end wall 11, in mm;

[0055] b represents the mass percentage of Ti based on the total mass of the steel, expressed in wt.%.

[0056] c represents the mass percentage of Nb based on the total mass of steel, expressed in wt.%.

[0057] The battery casing 1 is mostly cylindrical, including cylindrical and prismatic shapes. The battery casing 1 provided in this application is manufactured using a deep drawing process. During deep drawing, an opening is required for the punch to enter. This opening is typically one of the bottom surfaces of the cylindrical battery, while the other bottom surface is integrally formed with the side wall 13. In this application, the end wall 11 is defined as the surface integrally formed with the side wall 13, and an end cap 12 is provided at the opening. The end cap 12 is fixedly connected to the side wall 13, and can be welded, riveted, or bonded, etc., without affecting the implementation of this solution.

[0058] Cr is the main element determining the corrosion resistance of stainless steel. It can increase the electrode potential of the matrix, thereby significantly improving the corrosion resistance of the steel. In addition, as a major component of the oxide film, Cr helps to form a more stable oxide film and improves the oxidation resistance at high temperatures.

[0059] During deep drawing, after the end wall 11 is formed, the side wall 13 is stretched. At this time, the end wall 11 serves as the stretching reference, and the end wall thickness d remains basically unchanged. The initial thickness of the side wall 13 is the same as the end wall thickness d, and then decreases with stretching. Therefore, as the height h of the shell 1 increases, the deep drawing performance required by the shell 1 needs to be correspondingly improved. Especially when the end wall thickness d of the shell 1 is relatively thin, but the height h of the shell 1 is relatively high, that is, when the initial thickness of the side wall 13 is small but the stretching of the side wall 13 is relatively high, the side wall 13 formed during the stretching process will be even thinner. This places higher demands on the strength of the shell 1 to prevent breakage during the stretching process, requiring better deep drawing performance of the shell 1 to avoid hardening of the shell 1 during deep drawing, local stress concentration, and fracture.

[0060] In this application, by controlling the content of titanium (Ti) and niobium (Nb), the deep drawing properties of the steel can be regulated to a certain extent, avoiding stress concentration during deep drawing that could lead to fracture and increased defect rate. Especially when the end wall 11 is thin and the drawing height is high (i.e., the shell 1 is high), better deep drawing properties of the steel are required to prevent fracture of the shell 1 during deep drawing.

[0061] However, good deep drawing properties of steel mean that the steel is prone to deformation, which may result in poor pressure resistance after the casing 1 is formed, leading to a decrease in battery safety performance. Furthermore, if the deep drawing properties are poor, even if the casing 1 is formed, its mechanical properties will be poor, and its safety performance cannot be guaranteed. Therefore, it is necessary to balance the deep drawing properties of the casing 1 during processing with its pressure resistance after forming.

[0062] If the value of (h / d) / (b+c) is too small, it indicates that h / d is too small, or that the content of at least one of Ti and Nb is too high. If h / d is too small, the stretching degree will be insufficient, while if the content of Ti is too high, it may cause changes in the recrystallization behavior of stainless steel, thereby affecting the mechanical properties and corrosion resistance of stainless steel, which will lead to a decrease in the forming rate of shell 1. If the content of Nb is too high, it indicates that h / d is too large, or that the content of at least one of Ti and Nb is too low. The larger the h / d, the greater the stretching degree required. However, if the content of Ti and Nb is too low, the intergranular corrosion during deep drawing will increase, and the formability of shell 1 will deteriorate. Therefore, (h / d) / (b+c) needs to be controlled within an appropriate range.

[0063] Therefore, this application ensures that the mass percentage of Ti (b), the mass percentage of Nb (c), the thickness of the end wall 11 (d), and the height of the shell 1 (h) satisfy 50 ≤ (h / d) / (b+c) ≤ 7000. This allows the steel to have sufficient deep drawing properties to meet the required dimensions of the shell 1, preventing breakage during deep drawing, improving the processing yield, and also giving the formed shell 1 good mechanical properties to ensure battery safety.

[0064] In some embodiments of this application, the specific selection of (h / d) / (b+c) can be 50, 60, 70, 80, 90, 100, 110, 120, 135, 150, 200, 300, 500, 800, 1000, 2000, 3000, 4000, 5000, 6000, 6500, 6800, 6900, 6950, 7000, or it can be any range formed by any two of the above values, such as 100-6000, 135-5000, 1000-7000, etc.

[0065] In one embodiment, the housing 1 satisfies the following relationship: 142≤(h / d) / (b+c)≤2000.

[0066] In this scheme, the shell 1 that satisfies the above relationship has a higher processing yield during deep drawing.

[0067] In one embodiment, the range of h is 20-300 mm.

[0068] In some embodiments of this application, the specific selection of h can be 20mm, 25mm, 30mm, 35mm, 40mm, 50mm, 60mm, 70mm, 80mm, 100mm, 120mm, 150mm, 180mm, 200mm, 220mm, 250mm, 270mm, 280mm, 290mm, 295mm, or 300mm, or it can be a range formed by any two of the above values, such as 50-270mm, 100-220mm, or 80-300mm.

[0069] In one embodiment, the range of h is 50-270 mm.

[0070] In one embodiment, the range of d is 0.2-1.5 mm.

[0071] In some embodiments of this application, the specific selection of d can be 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.15mm, 1.2mm, 1.3mm, 1.4mm, 1.45mm, or 1.5mm, or it can be a range formed by any two of the above values, such as 0.4-1.0mm, 0.5-1.2mm, 0.2-0.8mm, etc.

[0072] In one embodiment, the range of d is 0.5-1.0 mm.

[0073] In one embodiment, the range of b+c is 0.2-0.8 wt.%.

[0074] In some embodiments of this application, the specific selection of b+c can be 0.2wt.%, 0.25wt.%, 0.3wt.%, 0.35wt.%, 0.4wt.%, 0.45wt.%, 0.5wt.%, 0.55wt.%, 0.6wt.%, 0.65wt.%, 0.7wt.%, 0.75wt.%, 0.8wt.%, or a range formed by any two of the above values, such as 0.2-0.5wt.%, 0.3-0.8wt.%, 0.25-0.5wt.%, etc.

[0075] In one embodiment, the range of b+c is 0.25-0.5 wt.%.

[0076] Both Ti and Nb are carbon and nitrogen stabilizing elements, capable of combining with carbon and nitrogen to form NbC, NbN, TiC, and TiN, thus increasing the strength of steel. Simultaneously, the precipitation of Ti carbides significantly enhances the plasticity and impact toughness of steel, ensuring good deep-drawing performance and inhibiting the formation of chromium carbon and nitrogen oxides, thereby improving the intergranular corrosion resistance of stainless steel. Trace amounts of Nb can increase the strength of steel without affecting its plasticity or toughness. Nb carbides and oxides, due to their grain-refining effect, can improve the impact toughness of steel and lower its brittle transition temperature.

[0077] In one embodiment, the range of b is 0.05-0.2 wt.%.

[0078] Excessive Nb can lead to the formation of coarse Fe2Nb hard phases, reducing the elongation and deep drawing properties of the material. Furthermore, too much NbN can also reduce the hot plasticity of steel. Therefore, the Nb content should be controlled within a certain range.

[0079] In some embodiments of this application, the specific selection of b can be 0.05wt.%, 0.07wt.%, 0.1wt.%, 0.12wt.%, 0.15wt.%, 0.17wt.%, 0.2wt.%, or it can be a range formed by any two of the above values, such as 0.05-0.15wt.%, 0.07-0.17wt.%, 0.1-0.2wt.%, etc.

[0080] In one embodiment, the range of c is 0.17-0.5 wt.%.

[0081] When the Ti content is high, there are more TiN inclusions and they are larger in size, which affects the surface quality of the steel. Therefore, the Ti content needs to be controlled within a certain range.

[0082] In some embodiments of this application, the specific selection of c can be 0.17wt.%, 0.2wt.%, 0.22wt.%, 0.25wt.%, 0.27wt.%, 0.3wt.%, 0.35wt.%, 0.4wt.%, 0.45wt.%, 0.5wt.%, or it can be a range formed by any two of the above values, such as 0.25-0.5wt.%, 0.17-0.35wt.%, 0.2-0.4wt.%, etc.

[0083] The testing methods for Ti, Nb, and Cr content are not limited, and those skilled in the art can detect the Ti, Nb, and Cr content using conventional methods, such as inductively coupled plasma atomic absorption spectrometry (ICP-AES) and X-ray fluorescence spectrometry.

[0084] Inductively coupled plasma method:

[0085] (1) Sample preparation: Stainless steel samples need to undergo appropriate pretreatment, such as dissolving in a specific acid solution to release the analyte. For example, aqua regia can be used to dissolve the sample, or a specific mixed acid system can be used for digestion to ensure effective release of the analyte.

[0086] (2) Analytical methods: The main analytical methods of ICP-OES include the standard curve method and the internal standard method. The standard curve method calculates the content of each element in the sample by plotting the relationship between the concentration of the standard solution and the emission intensity at the corresponding wavelength and comparing the emission intensity of the sample solution with the standard curve. The internal standard method selects an element with similar chemical properties to the analyte and a constant content in the sample as an internal standard. By comparing the emission intensity ratio of the analyte and the internal standard element, the influence of factors such as sample composition and experimental conditions is eliminated.

[0087] X-ray fluorescence spectroscopy

[0088] (1) Sample preparation: First, the stainless steel sample needs to be properly treated to allow X-rays to penetrate and excite fluorescence. This may include steps such as cutting, grinding, and polishing to ensure that the sample surface is flat and free of contamination.

[0089] (2) X-ray excitation: High-energy X-rays are used to irradiate the sample surface, exciting the characteristic X-ray fluorescence of each element. The wavelength or energy characteristics of these fluorescence spectra correspond to the element types, thus allowing the determination of which elements are contained in the sample.

[0090] (3) Spectral collection and analysis: X-rays reflected from the sample surface and fluorescence spectra emitted are collected using a spectrometer. The type and content of elements can be determined by using the position and intensity of characteristic spectral lines.

[0091] (4) Matrix effect correction: Due to the interaction between various elements in stainless steel (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.

[0092] (5) Interpretation of results: Based on the corrected data, the content of each element in stainless steel can be calculated, and its performance and quality can be evaluated.

[0093] In one embodiment, the housing 1 further includes a sidewall 13, and the housing 1 also satisfies the following relationship: 0.5≤(f / d) / (b+c)≤5, where f is the thickness of the sidewall 13 of the housing 1 in mm.

[0094] Since the end wall 11 and the side wall 13 are integrally formed by deep drawing, the greater the height of the shell 1, the greater the drawing ratio of the side wall 13, and the higher the requirements for the deep drawing performance of the steel. In particular, the change in thickness of the end wall 11 during deep drawing should be less than the change in thickness of the side wall 13. That is, in the same shell 1, the thickness of the side wall 13 will not exceed the thickness of the end wall 11. If the thickness of the end wall 11 is large but the thickness of the side wall 13 is small, it indicates that the material drawing ratio of the side wall 13 part is large, making it difficult to integrally form.

[0095] In some embodiments of this application, the selection of (f / d) / (b+c) can be 0.5, 0.6, 0.8, 1, 2, 3, 4, 4.5, 5, or it can be a range formed by any two of the above values, such as 0.5-2, 0.5-4.5, 1-5, etc.

[0096] In one embodiment, the range of f is 0.1-1.2 mm.

[0097] In some embodiments of this application, the specific selection of f can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.15mm, 1.2mm, or any range formed by any two of the above values, such as 0.2-0.8mm, 0.5-1.0mm, 0.2-0.5mm, etc.

[0098] In one embodiment, the range of d is 0.3-1.2 mm.

[0099] In some embodiments of this application, the specific selection of d can be 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, or it can be a range formed by any two of the above values, such as 0.3-1.0mm, 0.5-1.0mm, 0.4-0.8mm, etc.

[0100] In one embodiment, a pressure relief structure is provided on the end wall 11 at one end of the housing 1.

[0101] The pressure relief structure on a battery cell plays a crucial role in its safety. For example, in the event of a short circuit or overcharging, thermal runaway may occur within the battery cell, causing a sudden increase in pressure or temperature. In such cases, the pressure relief structure releases the internal pressure and temperature to the outside, preventing the battery cell from exploding or catching fire. The specific form of the pressure relief structure is not limited; it is mainly used to release pressure in a timely manner when thermal runaway occurs. Its structure can be a separate explosion-proof plate, with a hole in the housing 1 and the explosion-proof plate connected to the hole, or the explosion-proof structure can be directly stamped onto the housing 1 or formed by etching.

[0102] In one embodiment, the pressure relief structure includes a weak part 2, and the shell 1 also satisfies the following relationship: 0.004≤m×(b+c)≤0.12, where m is the residual thickness of the weak part 2 in mm.

[0103] When the pressure relief structure releases pressure, it bursts open at the weak point 2 on the explosion-proof sheet when the preset pressure is reached, thus ensuring battery safety. The weak point 2 can be a thinned portion formed on the explosion-proof sheet by stamping or laser etching. The remaining thickness of the thinned portion is the thickness remaining after the explosion-proof sheet has been thinned by stamping or laser etching. The direction of the remaining thickness of the thinned portion is parallel to the thickness direction of the end wall 11, and the remaining thickness of the thinned portion is less than the thickness of the end wall 11. The shape of the weak point 2 can be similar to that of the explosion-proof sheet, i.e., a ring-shaped thinned portion is stamped out along the edge of the explosion-proof sheet. In this method, the weak point 2 has a large area and is easier to burst open. Alternatively, the thinned portion can be incomplete, retaining at least one un-thinned area on the ring-shaped thinned portion. This way, after pressure relief, the explosion-proof sheet still has a connection point to prevent the entire explosion-proof sheet from flying off and causing a safety hazard.

[0104] In this design, the pressure relief structure is integrally formed on the casing 1 through stamping or laser etching. Since the pressure relief structure is integrally formed with the casing 1, to ensure the processing yield, the strength of the casing 1, and the triggering pressure of the pressure relief structure, the dimensions of the pressure relief structure must be compatible with the deep drawing capacity of the casing 1. The bursting pressure of the pressure relief structure is related to the strength of the material and the hardness of the weak part 2. To avoid accidental triggering of the pressure relief structure, the residual thickness of the weak part 2 needs to be controlled. By controlling Ti and Nb within a specific range, the strength of the steel is improved, allowing for a suitable reduction in the size of m, making the weak part 2 thinner. This facilitates the bursting of the pressure relief structure in the event of thermal runaway, thus protecting battery safety. Meanwhile, if m×(b+c) is too small, the low content of Ti and Nb will result in poor formability, and the small residual thickness m of the weak part 2 will lead to low strength at the pressure relief structure location, making it prone to accidental explosion. If m×(b+c) is too large, the high content of Ti and Nb will result in a lower formability, and the large residual thickness m of the weak part 2 will be unfavorable for the pressure relief structure to explode and release heat when thermal runaway occurs in the battery. Therefore, m×(b+c) needs to be controlled within a suitable range.

[0105] When the end wall 11, side wall 13, weak part 2 and through hole 3 on the end wall 11 are integrally formed in the shell 1, the processing performance during deep drawing, the strength of the shell 1 after forming, and the burst pressure of the pressure relief structure need to be considered. This application limits the relationship and range between the residual thickness m of the weak part 2 and the content of Ti and Nb, the ratio z of the area of ​​the injection hole 4 and the area of ​​the end wall 11 and the content of Ti and Nb, and further controls the content of Ti and Nb to meet the deep drawing processing requirements of the height and end wall thickness of the shell 1. This ensures that when the weak part 2 and through hole 3 of the end wall 11 are deep drawn, the performance of the steel can meet the requirements of the deep drawing process and the shell 1 after forming has sufficient strength.

[0106] In some embodiments of this application, the m×(b+c) can be selected from 0.004, 0.005, 0.006, 0.008, 0.01, 0.02, 0.04, 0.05, 0.08, 0.1, 0.11, 0.115, 0.12, or from any two of the above values, such as 0.004-0.08, 0.005-0.05, 0.01-0.12, etc.

[0107] In one embodiment, the range of m is 0.01-0.5 mm.

[0108] In some embodiments of this application, the specific selection of m can be 0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.08mm, 0.1mm, 0.12mm, 0.15mm, 0.18mm, 0.20mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, or 0.5mm, or it can be any range formed by any two of the above values, such as 0.1-0.5mm, 0.01-0.1mm, 0.2-0.4mm, etc.

[0109] In one embodiment, the housing 1 is provided with an end cap 12 at the other end opposite to the end wall 11. The end cap 12 is fixedly connected to the side wall 13. The end wall 11 or the end cap 12 is provided with a through hole 3 for setting the pole post assembly 5.

[0110] In one embodiment, the through hole 3 is provided on the end wall 11, and the housing 1 also satisfies the following relationship: 0.005≤k / (b+c)≤0.5, where k is the ratio of the area of ​​the through hole 3 to the area of ​​the end wall 11 where the through hole 3 is located.

[0111] The through-hole 3 can be located on the end wall 11 of the housing 1 or on the end cap 12. In this design, the through-hole 3 is located on the end wall 11. Since the end wall 11 is integrally formed with the housing 1, and the pressure relief structure is also located on the end wall 11, in order to ensure the machining efficiency and the strength of the housing 1, the ratio of the area of ​​the through-hole 3 to the area of ​​the end wall 11 needs to be compatible with the deep drawing capacity of the housing 1. In this design, the electrode assembly 5 is electrically connected to the internal battery cell through the through-hole 3. The cross-sectional area of ​​the electrode affects the current flow. By controlling the content of Ti and Nb within a certain range, the strength of the housing 1 is increased, thereby allowing for a larger through-hole 3 to accommodate a larger electrode assembly 5 and improve the current flow. The ratio k / (b+c) needs to be within a suitable range. If k / (b+c) is too small, the small area of ​​the through-hole 3 will limit the cross-sectional area of ​​the pole, resulting in insufficient current flow capacity, excessively high Ti and Nb content, and reduced molding yield of the shell 1. If k / (b+c) is too large, the area of ​​the through-hole 3 will be relatively large while the Ti and Nb content will be relatively low. Since the Ti and Nb content of the end wall 11 is low, the shell 1 itself is relatively fragile. An excessively large through-hole 3 area will further weaken the strength of the end wall 11, increasing the risk of deformation of the shell 1. Therefore, k / (b+c) needs to be set within a suitable range.

[0112] In some embodiments of this application, the specific selection of k / (b+c) can be 0.005, 0.006, 0.008, 0.01, 0.02, 0.05, 0.08, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.42, 0.45, 0.47, or 0.5, or it can be any range formed by any two of the above values, such as 0.05-0.5, 0.005-0.4, 0.1-0.5, etc.

[0113] In one embodiment, the range of k is 0.00125-0.1.

[0114] In some embodiments of this application, the specific selection of k can be 0.00125, 0.0013, 0.0014, 0.0015, 0.0017, 0.002, 0.0025, 0.003, 0.004, 0.005, 0.008, 0.01, 0.02, 0.03, 0.05, 0.07, 0.08, 0.09, 0.095, or 0.1, or it can be any range formed by any two of the above values, such as 0.00125-0.05, 0.01-0.1, 0.0025-0.1, etc.

[0115] In one embodiment, the end wall 11 is provided with a liquid injection hole 4, and the housing 1 also satisfies the following relationship: 0.004≤z / (b+c)≤0.3, where z is the ratio of the area of ​​the liquid injection hole 4 to the area of ​​the end wall 11.

[0116] Because the content of Ti and Nb is controlled within a certain range, the strength of the shell 1 increases, and the increase in the area of ​​the injection hole 4 does not weaken the overall strength of the end wall 11. The increased content of Ti and Nb improves the corrosion resistance, strengthens the end wall 11, and thus increases the ratio z of the area of ​​the injection hole 4 to the area of ​​the end wall 11, thereby improving the injection efficiency. z / (b+c) needs to be within a suitable range. If z / (b+c) is too small, the area of ​​the injection hole 4 will be too small, which will affect the injection efficiency. If the content of Ti and Nb is too high, the forming rate of the shell 1 will be low. If z / (b+c) is too large, the area of ​​the injection hole 4 will be too large, which will make the end wall 11 easy to deform. If the content of Ti and Nb is low, the shell 1 will be easily corroded.

[0117] In some embodiments of this application, z / (b+c) can be specifically selected from 0.004, 0.0045, 0.005, 0.007, 0.01, 0.02, 0.04, 0.05, 0.06, 0.08, 0.1, 0.15, 0.2, 0.25, 0.27, 0.28, 0.29, 0.3, or from any two of the above values, such as 0.004-0.05, 0.005-0.1, 0.01-0.03, etc.

[0118] In one embodiment, the range of z is 0.001-0.08.

[0119] In some embodiments of this application, z can be specifically selected as 0.001, 0.00125, 0.002, 0.003, 0.0035, 0.004, 0.0045, 0.0047, 0.005, 0.006, 0.007, 0.0075, 0.008, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.075, 0.08, or any interval range formed by any two of the above values, such as 0.00125-0.05, 0.001-0.05, 0.008-0.08, etc.

[0120] The positions of the through hole 3 and the injection hole 4 can be as shown in Figure 3, with the through hole 3 located on the end cap 12 and the injection hole 4 located on the end wall 11; or as shown in Figure 5, with the through hole 3 located on the end wall 11 and the injection hole 4 located on the end cap 12; or both the through hole 3 and the injection hole 4 can be located at the same end of the housing, in which case a hole needs to be made in the terminal assembly as the injection hole. Having the through hole 3 and the injection hole 4 located at opposite ends of the housing facilitates battery assembly.

[0121] In one embodiment, the steel composition further includes C, Si, Mn, P, S and Fe.

[0122] In some embodiments, the steel comprises Fe and the following components in mass percentage: C: greater than 0 and less than or equal to 0.03%, Si: 0 to 0.75%, Mn: 0 to 1.0%, P: 0 to 0.04%, S: 0 to 0.03%, Cr: 16 to 30%, Ti: 0.05 to 0.2%, Nb: 0.17 to 0.5%, and 0.5% unavoidable impurities.

[0123] Methods for determining the content of each component:

[0124] The testing methods for Ti, Nb, and Cr content are not limited, and those skilled in the art can detect the Ti, Nb, and Cr content using conventional methods. For example, inductively coupled plasma method, X-ray fluorescence spectrometry, or other testing methods will not affect the implementation of this solution.

[0125] Inductively coupled plasma method:

[0126] (1) Sample preparation: Stainless steel samples need to undergo appropriate pretreatment, such as dissolving in a specific acid solution to release the analyte. For example, aqua regia can be used to dissolve the sample, or a specific mixed acid system can be used for digestion to ensure effective release of the analyte.

[0127] (2) Analytical Methods: The main analytical methods of ICP-OES include the standard curve method and the internal standard method. The standard curve method involves plotting the relationship between the concentration of a standard solution and the emission intensity at the corresponding wavelength, comparing the emission intensity of the sample solution with the standard curve to determine the content of each element in the sample. The internal standard method selects an element with similar chemical properties to the analyte and a constant content in the sample as an internal standard. By comparing the emission intensity ratio of the analyte and the internal standard element, the influence of factors such as sample composition and experimental conditions is eliminated.

[0128] X-ray fluorescence spectroscopy

[0129] (1) Sample preparation: First, the stainless steel sample needs to be properly treated to allow X-rays to penetrate and excite fluorescence. This may include steps such as cutting, grinding, and polishing to ensure that the sample surface is flat and free of contamination.

[0130] (2) X-ray excitation: High-energy X-rays are used to irradiate the sample surface, exciting the characteristic X-ray fluorescence of each element. The wavelength or energy characteristics of these fluorescence spectra correspond to the element types, thus allowing the determination of which elements are contained in the sample.

[0131] (3) Spectral collection and analysis: X-rays reflected from the sample surface and fluorescence spectra emitted are collected using a spectrometer. The type and content of elements can be determined by using the position and intensity of characteristic spectral lines.

[0132] (4) Matrix effect correction: Due to the interaction between various elements in stainless steel (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.

[0133] (5) Interpretation of results: Based on the corrected data, the content of each element in stainless steel can be calculated, and its performance and quality can be evaluated.

[0134] In this application, the forming method of the shell 1 is not specifically limited. Those skilled in the art can perform deep drawing processing on the shell 1 according to conventional technical means.

[0135] For example, in some embodiments, the battery manufacturing process is as follows:

[0136] 1. Preparation of the shell:

[0137] (1) Steel preparation: The molten steel is smelted to remove impurities and finely adjusted according to the target chemical composition required by shell 1. After obtaining the molten steel with the composition as described above, it is cast to obtain steel ingots.

[0138] (2) Preparation of blanks: The steel ingots are rolled into coils, and then the coils are cut into plates of appropriate size;

[0139] (3) Deep drawing: Place the sheet in a suitable mold and fix it, then press the punch on the mold with a certain force and repeat the drawing until the shell 1 is formed.

[0140] (4) Trimming: Remove and trim excess material during deep drawing to ensure that the burrs and flatness of the cut meet the requirements.

[0141] 2. Preparation of the positive electrode sheet

[0142] The positive electrode active material, conductive agent acetylene black, and binder PVDF were mixed at a mass ratio of 96:2:2. NMP solvent was added, and the mixture was stirred under vacuum until homogeneous to obtain the positive electrode slurry. The positive electrode slurry was uniformly coated onto both surfaces of the positive electrode current collector aluminum foil, air-dried at room temperature, and then transferred to an oven for further drying. Finally, it was cold-pressed and slit to obtain the positive electrode sheet.

[0143] 3. Preparation of negative electrode sheet

[0144] The negative electrode active material, conductive agent (SP), and binder are mixed in a certain mass ratio (97:1:1), and deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector copper foil, air-dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the negative electrode sheet is obtained.

[0145] 4. Preparation of electrolyte

[0146] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent. FEC was added according to the examples and comparative examples. Then, fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a lithium salt concentration of 1 mol / L.

[0147] 5. Preparation of the diaphragm

[0148] In this embodiment, polyethylene film is selected as the diaphragm, and the polyethylene film is cut to form the diaphragm.

[0149] 6. Preparation of lithium-ion batteries

[0150] The positive electrode, separator, and negative electrode are stacked in sequence, with the separator positioned between the positive and negative electrodes to act as an isolation layer. Then, the cells are wound up to obtain the bare battery cell.

[0151] The battery cell is placed in the housing 1 (prepared as described above), and the end cap 12 and the housing 1 are connected together by laser welding; after drying, liquid is injected, formation is performed, and the volume is adjusted to obtain the prepared lithium-ion battery.

[0152] This application also provides a battery, including the battery casing described above.

[0153] This application also provides an electrical device, including the battery described above.

[0154] The present application is further illustrated below with specific embodiments:

[0155] Examples 1-17

[0156] Examples 1-17 each provide a shell 1, the chemical composition of which includes: C, Si, Mn, P, S, Ti, Nb, Cr and Fe;

[0157] Based on the total mass of the steel, the mass percentages of C, Si, Mn, P, and S are as follows: C: 0.03%, Si: 0.7%, Mn: 0.95%, P: 0.04%, S: 0.03%, and Cr: 16%.

[0158] The mass percentages of Ti and Nb are shown in Table 1;

[0159] The remainder is Fe.

[0160] As shown in Figures 1-5, the height h of the shell 1 after deep drawing, the thickness d of the end wall 11, the thickness f of the side wall 13 of the shell 1, the residual thickness m of the weak part 2 after the explosion-proof valve is engraved, the ratio k of the area of ​​the through hole 3 after punching to the area of ​​the end wall 11 where the through hole 3 is located, and the ratio z of the injection hole 4 to the area of ​​the end wall 11 where the injection hole 4 is located are shown in Table 1.

[0161] The battery is manufactured as follows:

[0162] 1. Preparation of the shell

[0163] (1) Steel preparation: The molten steel is smelted to remove impurities and finely adjusted according to the target chemical composition required by shell 1. After obtaining the molten steel with the composition as described above, it is cast to obtain steel ingots.

[0164] (2) Preparation of blanks: The steel ingot is rolled into a coil. During the rolling process, the thickness of the coil is adjusted by adjusting the size, gap and speed of the rolling mill rollers to prepare shells with different end wall thicknesses d. Then the coil is cut into plates of appropriate size.

[0165] (3) Deep drawing: Place the sheet metal into a suitable mold and fix it. Then, press the punch onto the mold with a certain force and repeat the drawing until the shell 1 is formed. The area of ​​the end wall 11 of the formed shell 1 is 1661.06 mm2.

[0166] (4) Trimming: Remove and trim excess material during deep drawing to ensure that the burrs and flatness of the cut meet the requirements.

[0167] 2. Preparation of the positive electrode sheet

[0168] The positive electrode active material, conductive agent acetylene black, and binder PVDF were mixed at a mass ratio of 96:2:2. NMP solvent was added, and the mixture was stirred under vacuum until homogeneous to obtain the positive electrode slurry. The positive electrode slurry was uniformly coated onto both surfaces of the positive electrode current collector aluminum foil, air-dried at room temperature, and then transferred to an oven for further drying. Finally, it was cold-pressed and slit to obtain the positive electrode sheet.

[0169] 3. Preparation of negative electrode sheet

[0170] The negative electrode active material, conductive agent (SP), and binder are mixed in a certain mass ratio (97:1:1), and deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector copper foil, air-dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the negative electrode sheet is obtained.

[0171] 4. Preparation of electrolyte

[0172] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent. FEC was added according to the examples and comparative examples. Then, fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a lithium salt concentration of 1 mol / L.

[0173] 5. Preparation of the diaphragm

[0174] In this embodiment, polyethylene film is selected as the diaphragm, and the polyethylene film is cut to form the diaphragm.

[0175] 6. Preparation of lithium-ion batteries

[0176] The positive electrode, separator, and negative electrode are stacked in sequence, with the separator positioned between the positive and negative electrodes to act as an isolation layer. Then, the cells are wound up to obtain the bare battery cell.

[0177] The battery cell is placed in the housing 1 (prepared as described above), and the end cap 12 and the housing 1 are connected together by laser welding; after drying, liquid is injected, formation is performed, and the volume is adjusted to obtain the prepared lithium-ion battery.

[0178] X-ray fluorescence spectroscopy

[0179] (1) Sample preparation: First, the stainless steel sample needs to be properly treated to allow X-rays to penetrate and excite fluorescence. This may include steps such as cutting, grinding, and polishing to ensure that the sample surface is flat and free of contamination.

[0180] (2) X-ray excitation: High-energy X-rays are used to irradiate the sample surface, exciting the characteristic X-ray fluorescence of each element. The wavelength or energy characteristics of these fluorescence spectra correspond to the element types, thus allowing the determination of which elements are contained in the sample.

[0181] (3) Spectral collection and analysis: X-rays reflected from the sample surface and fluorescence spectra emitted are collected using a spectrometer. The type and content of elements can be determined by using the position and intensity of characteristic spectral lines.

[0182] (4) Matrix effect correction: Due to the interaction between various elements in stainless steel (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.

[0183] (5) Interpretation of results: Based on the corrected data, the content of each element in stainless steel can be calculated, and its performance and quality can be evaluated.

[0184] The measurement methods for d, m, and f are as follows:

[0185] The thickness of the end wall 11, the weak part 2, and the side wall 13 is measured using an ultrasonic thickness gauge. During the measurement, the thickness is measured at three different locations on the test object and the average value is taken.

[0186] The method for measuring h is as follows:

[0187] The height of housing 1 was measured using a laser height measuring instrument. During the measurement, measurements were taken at three different locations on the test object and the average value was taken.

[0188] Area of ​​through hole 3, injection hole 4, and end wall 11:

[0189] The diameters of through hole 3, injection hole 4, and end wall 11 were measured using vernier calipers, and the areas of through hole 3, injection hole 4, and end wall 11 were calculated using the formula for the area of ​​a circle. Finally, k and z were calculated.

[0190] Examples 18-26

[0191] Examples 18-26 are similar to Example 1, except that the mass percentages of Ti and Nb are shown in Table 2, and the height h of the shell 1, the thickness d of the end wall 11, and the thickness f of the side wall 13 of the shell 1 after deep drawing are shown in Table 2.

[0192] Examples 27-32

[0193] Examples 27-32 are similar to Example 1, except that the mass percentages of Ti and Nb are shown in Table 3, and the height h of the shell 1 after deep drawing, the thickness d of the end wall 11, and the residual thickness m of the weak part 2 after the explosion-proof valve is engraved are shown in Table 3.

[0194] Examples 33-38

[0195] Examples 33-38 are similar to Example 1, except that, as shown in Figure 5, the through hole 3 is located on the end wall 11, and the injection hole 4 is located on the end cap 12. The mass percentages of Ti and Nb are shown in Table 4. The height h of the shell 1 after deep drawing, the thickness d of the end wall 11, and the ratio k of the area of ​​the through hole 3 after punching to the area of ​​the end wall 11 where the through hole 3 is located are shown in Table 4.

[0196] Examples 39-44

[0197] Examples 39-44 are similar to Example 1, except that, as shown in Figures 3 and 4, the injection hole 4 is located on the end wall 11, and the through hole 3 is located on the end cap 12. The mass percentages of Ti and Nb are shown in Table 5. The height h of the shell 1 after deep drawing, the thickness d of the end wall 11, and the ratio z of the injection hole 4 and the area of ​​the end wall 11 where the injection hole 4 is located are shown in Table 5.

[0198] Example 45

[0199] Example 45 is similar to Example 1, except that, as shown in Figure 6, the shell 1 is a square shell. The height h of the shell 1 after deep drawing, the thickness d of the end wall 11, the thickness f of the side wall 13 of the shell 1, the residual thickness m of the weak part 2 after the explosion-proof valve is engraved, the ratio k of the area of ​​the through hole 3 after punching to the area of ​​the end wall 11 where the through hole 3 is located, and the ratio z of the area of ​​the injection hole 4 and the area of ​​the end wall 11 where the injection hole 4 is located are shown in Table 1.

[0200] The forming method of the square shell is as follows:

[0201] (1) Steel preparation: The molten steel is smelted to remove impurities and finely adjusted according to the target chemical composition required by shell 1. After obtaining the molten steel with the composition as described above, it is cast to obtain steel ingots.

[0202] (2) Preparation of blanks: The steel ingot is rolled into a coil. During the rolling process, the thickness of the coil is adjusted by adjusting the size, gap and speed of the rolling mill rollers to prepare shells with different end wall thicknesses d. Then the coil is cut into plates of appropriate size.

[0203] (3) Deep drawing: Place the sheet in a suitable mold and fix it. Then press the punch on the mold with a certain force. Change the square mold and punch to make the round to square. Repeat the drawing until the shell 1 is formed.

[0204] (4) Trimming: Remove and trim excess material during deep drawing to ensure that the burrs and flatness of the cut meet the requirements.

[0205] Comparative Examples 1-3

[0206] Comparative Examples 1-3 are similar to Example 1, except that the mass percentages of Ti and Nb, the height h of the shell 1 after deep drawing, and the thickness d of the end wall 11 are different, as detailed in Table 1.

[0207] Table 1

[0208] Table 2

[0209] Table 3

[0210] Table 4

[0211] Table 5

[0212] Performance testing:

[0213] The performance testing methods for the above comparative examples and embodiments are as follows:

[0214] 1. Shell pressure bearing capacity test:

[0215] (1) Pressure holding test: First, seal the injection hole 4 with AB glue or structural glue; then put the shell 1 into the explosion / pressure resistance test fixture, connect the air inlet to the explosion instrument, adjust to the pressure holding mode, and inflate the shell 1 with air to the required air pressure (such as 3Mpa, 4Mpa, 5Mpa) and hold for 30s.

[0216] (2) Air tightness test: After the pressure holding test, the shell 1 is subjected to a helium leak test. If the leakage rate is ≤1×10-7 Pa·m 3 If the pressure is / s, then the pressure resistance of shell 1 is qualified under this pressure.

[0217] 2. Deep drawing forming pass rate of the shell

[0218] The shell 1 was deep drawn according to the above-mentioned preparation method, and the deep drawing success rate of 200 shells 1 was statistically analyzed.

[0219] As can be seen from Table 1, in Examples 1-17 and 45, the shell 1 with a height h, end wall thickness d, Ti mass percentage b, and Nb mass percentage c all satisfying 50 ≤ (h / d) / (b+c) ≤ 7000 has a stronger pressure-bearing capacity compared to Comparative Examples 1-3. Furthermore, it is less prone to local stress concentration leading to fracture during deep drawing, resulting in a higher deep drawing forming pass rate, making it more suitable for deep drawing processing. Further, when the shell 1 satisfies 142 ≤ (h / d) / (b+c) ≤ 2000, its deep drawing forming pass rate is further improved. In particular, when the shell 1 also simultaneously satisfies 50 mm ≤ h ≤ 270 mm, 0.5 mm ≤ d ≤ 1.0 mm, and 0.25 wt.% ≤ (b+c) ≤ 0.35 wt.%, the deep drawing forming pass rate of the shell 1 is even higher.

[0220] As shown in Table 2, Examples 18-26 all satisfy 142≤(h / d) / (b+c)≤2000. Based on this, considering that the thickness of the sidewall 13 of the shell 1 after deep drawing must be less than that of the end wall 11, a large difference in thickness between the sidewall 13 and the end wall 11 indicates a large stretching ratio for the sidewall 13, thus requiring higher deep drawing performance of the material. Examples 18-26 show that when 0.5≤f / (b+c)≤5 is satisfied, the deep drawing success rate of the shell 1 is higher. Furthermore, when the shell 1 also satisfies 0.1mm≤f≤1.2mm, the shell 1 is more suitable for deep drawing, further improving its deep drawing success rate, and the shell 1 after deep drawing has better pressure-bearing capacity.

[0221] As can be seen from Table 3, Examples 27-32 all satisfy 142≤(h / d) / (b+c)≤2000. When the weak part 2 of the battery pressure relief structure is integrally formed with the battery casing 1 through deep drawing, if 0.01≤m×(b+c)≤0.12 is satisfied, the weak part 2 can be better deep drawn, and the deep drawing success rate of the casing 1 is higher. In particular, when the casing 1 also satisfies 0.05mm≤m≤0.12mm, the casing 1 is more suitable for deep drawing, its deep drawing success rate is further improved, and the pressure-bearing capacity of the casing 1 after deep drawing is stronger.

[0222] As can be seen from Table 4, Examples 33-38 all satisfy 142≤(h / d) / (b+c)≤2000. When a through hole 3 for the pole post assembly 5 needs to be provided on the end wall 11 of the housing 1, if the housing 1 also satisfies 0.005≤k / (b+c)≤0.5, the housing 1 can have a sufficient deep drawing forming pass rate, while the pressure bearing capacity is not reduced. In particular, when the housing 1 also satisfies 0.00125≤k≤0.1, the deep drawing forming pass rate is further improved, the pressure bearing capacity is stronger, and the safety of the formed housing 1 is higher.

[0223] As can be seen from Table 5, Examples 39-44 all satisfy 142≤(h / d) / (b+c)≤2000. When it is necessary to set the injection hole 4 on the end wall 11 of the shell 1, if the shell 1 also satisfies 0.000225≤z / (b+c)≤0.1, the shell 1 can have a sufficient deep drawing forming pass rate. At the same time, the pressure bearing capacity of the shell 1 after punching is not reduced. In particular, when the shell 1 also satisfies 0.000225≤k≤0.1, the deep drawing forming pass rate is further improved, the pressure bearing capacity is stronger, and the shell 1 after forming is safer.

[0224] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. A battery casing, wherein the material of the casing (1) comprises steel, characterized in that, The steel composition includes Ti, Nb and Cr, wherein, based on the total mass of the steel, the mass percentage of Cr is ≥16 wt.%. The housing (1) includes a side wall (13) and an end wall (11) integrally formed with the side wall (13); The shell (1) satisfies the following relationship: 50≤(h / d) / (b+c)≤7000; Where h is the height of shell (1), in mm; d is the thickness of the end wall (11), in mm; b represents the mass percentage of Ti based on the total mass of the steel, expressed in wt.%. c represents the mass percentage of Nb based on the total mass of steel, expressed in wt.%.

2. The battery casing according to claim 1, characterized in that, The shell (1) satisfies the following relationship: 142≤(h / d) / (b+c)≤2000.

3. The battery casing according to claim 1 or 2, characterized in that, The range of h is 20-300 mm.

4. The battery casing according to claim 3, characterized in that, The range of h is 50-270 mm.

5. The battery casing according to claim 1 or 2, characterized in that, The range of d is 0.2-1.5 mm.

6. The battery casing according to claim 5, characterized in that, The range of d is 0.5-1.0 mm.

7. The battery casing according to claim 1, characterized in that, The range of b+c is 0.2-0.8 wt.%.

8. The battery casing according to claim 7, characterized in that, The range of b+c is 0.25-0.5 wt.%.

9. The battery casing according to claim 7, characterized in that, The range of b is 0.05-0.2 wt.%.

10. The battery casing according to claim 7, characterized in that, The range of c is 0.17-0.5 wt.%.

11. The battery casing according to claim 1, characterized in that, The shell (1) also satisfies the following relationship: 0.5≤(f / d) / (b+c)≤5, where f is the thickness of the side wall (13) of the shell (1) in mm.

12. The battery casing according to claim 11, characterized in that, The range of f is 0.1-1.2 mm.

13. The battery casing according to claim 11, characterized in that, The range of d is 0.3-1.2 mm.

14. The battery casing according to claim 1, characterized in that, The end wall (11) of the housing (1) is provided with a pressure relief structure.

15. The battery casing according to claim 14, characterized in that, The pressure relief structure includes a weak part (2), and the shell (1) also satisfies the following relationship: 0.004≤m×(b+c)≤0.12, where m is the residual thickness of the weak part (2) in mm.

16. The battery casing according to claim 15, characterized in that, The range of m is 0.01-0.5 mm.

17. The battery casing according to claim 1 or 14, characterized in that, The housing (1) has an end cap (12) on the other end relative to the end wall (11). The end cap (12) is fixedly connected to the side wall (13). The end wall (11) or the end cap (12) has a through hole (3) for setting the pole assembly (5).

18. The battery casing according to claim 17, characterized in that, The through hole (3) is provided on the end wall (11), and the shell (1) also satisfies the following relationship: 0.005≤k / (b+c)≤0.5, where k is the ratio of the area of ​​the through hole (3) to the area of ​​the end wall (11) where the through hole (3) is located.

19. The battery casing according to claim 18, characterized in that, The range of k is 0.00125-0.

1.

20. The battery casing according to claim 1, characterized in that, The end wall (11) is provided with a liquid injection hole (4), and the shell (1) also satisfies the following relationship: 0.004≤z / (b+c)≤0.3, where z is the ratio of the area of ​​the liquid injection hole (4) to the area of ​​the end wall (11).

21. The battery casing according to claim 20, characterized in that, The range of z is 0.001-0.

08.

22. The battery casing according to claim 1, characterized in that, The steel also contains C, Si, Mn, P, S and Fe.

23. A battery, characterized in that, Includes the battery casing as described in any one of claims 1-22.

24. An electrical appliance, characterized in that, Includes the battery as described in claim 23.

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