A battery case, a battery including the case, and an electric device using the battery

Abstract

The present application relates to the technical field of battery, more particularly, to a battery shell, a battery comprising the shell and an electric device using the battery. The material of the shell comprises steel, the components of the steel comprise Ti, Nb and Cr, wherein, based on the total mass of the steel, the mass percentage of Cr is greater than or equal to 16 wt.%; the shell comprises a side wall and an end wall integrally formed with the side wall; the shell satisfies the following relationship: 50 <= (h / d) / (b+c) <= 7000; wherein, h is the height of the shell, in mm; d is the thickness of the end wall, in mm; b is the mass percentage of Ti, based on the total mass of the steel, in wt.%; c is the mass percentage of Nb, based on the total mass of the steel, in wt.%. By controlling the relationship between the content of Ti and Nb and the height of the shell and the thickness of the end wall, the steel with the content of Ti and Nb can satisfy the deep drawing processing performance of the battery shell, and the formed shell has good pressure bearing capacity.

Description

[0001] This application is a divisional application of CN202411556207.7 (application date is November 4, 2024, application number is 202411556207.7; the name of the invention is a battery shell, a battery including the shell and its electrical device). Technical Field

[0002] The present invention relates to the technical field of batteries, and in particular to a battery housing, a battery comprising the housing, and an electrical device thereof. Background Art

[0003] With the increasing popularity of new energy vehicles, power batteries, as core components of new energy vehicles, directly determine the vehicle's range, performance, and overall safety. The battery housing, as a crucial component of the power battery, is crucial to various battery properties, including safety, energy density, and service life. Therefore, the battery housing must be lightweight while also possessing excellent mechanical properties.

[0004] Deep metal drawing involves deforming sheet metal into cylindrical or box-shaped parts using stamping, ring drawing, or die-cutting techniques. The process offers high productivity and material utilization, ensuring dimensional accuracy and low surface roughness. It can also produce thin-walled and complex parts that are difficult to form using other machining methods. With increasingly fierce price competition, battery casings are currently mostly made using deep metal drawing to reduce raw material and process costs. This requires the casing material to possess excellent tensile ductility.

[0005] Currently, stainless steel is widely used in products requiring deep drawing due to its high elongation, ability to form complex shapes with minimal defects, and excellent work-hardening properties. However, when stainless steel is used in deep drawing, its strength continues to increase due to work hardening, and stress concentration can lead to localized fractures. Summary of the Invention

[0006] The purpose of the present invention is to overcome the disadvantage of the prior art that steel used as the material of a battery housing is prone to fracture during deep drawing processing, and to provide a battery housing, a battery including the housing, and an electrical device thereof.

[0007] To achieve the above objectives, in a first aspect of the present invention, a battery housing is provided, wherein the housing material comprises steel, the components of the steel comprising Ti, Nb and Cr, wherein the mass percentage of Cr is ≥16 wt.% based on the total mass of the steel;

[0008] The housing includes an end wall;

[0009] The housing satisfies the following relationship: 50≤(h / d) / (b+c)≤7000;

[0010] Wherein, h is the height of the shell, in mm;

[0011] d is the thickness of the end wall, in mm;

[0012] b is the mass percentage of Ti based on the total mass of steel, in wt.%;

[0013] c is the mass percentage of Nb based on the total mass of the steel, in wt.%.

[0014] As a preferred embodiment of the present invention, the housing satisfies the following relationship: 142≤(h / d) / (b+c)≤2000.

[0015] As a preferred embodiment of the present invention, the range of h is 20-300 mm.

[0016] As a preferred embodiment of the present invention, the range of h is 50-270 mm.

[0017] As a preferred embodiment of the present invention, the range of d is 0.2-1.5 mm.

[0018] As a preferred embodiment of the present invention, the range of d is 0.5-1.0 mm.

[0019] As a preferred embodiment of the present invention, the range of b+c is 0.2-0.8 wt.%.

[0020] As a preferred embodiment of the present invention, the range of b+c is 0.25-0.5 wt.%.

[0021] As a preferred embodiment of the present invention, the range of b is 0.05-0.2 wt.%.

[0022] As a preferred embodiment of the present invention, the range of c is 0.17-0.5 wt.%.

[0023] As a preferred embodiment of the present invention, the shell further includes a side wall, and the shell further satisfies the following relationship: 0.5≤(f / d) / (b+c)≤5, wherein f is the thickness of the shell side wall, and its unit is mm.

[0024] As a preferred embodiment of the present invention, the range of f is 0.1-1.2 mm.

[0025] As a preferred embodiment of the present invention, the range of d is 0.3-1.2 mm.

[0026] As a preferred embodiment of the present invention, a pressure relief structure is provided on the end wall of one end of the shell.

[0027] As a preferred embodiment of the present invention, the pressure relief structure includes a weak portion, and the shell also satisfies the following relationship: 0.004≤m×(b+c)≤0.12, wherein m is the residual thickness of the weak portion, in mm.

[0028] As a preferred embodiment of the present invention, the range of m is 0.01-0.5 mm.

[0029] As a preferred embodiment of the present invention, an end cover is provided on the other end of the shell relative to the end wall, the end cover is fixedly connected to the side wall, and a through hole for arranging a pole assembly is provided on the end wall or the end cover.

[0030] As a preferred embodiment of the present invention, the through hole is provided on the end wall, and the shell further satisfies the following relationship: 0.005≤k / (b+c)≤0.5, wherein k is the ratio of the area of ​​the through hole to the area of ​​the end wall where the through hole is located.

[0031] As a preferred embodiment of the present invention, the range of k is 0.00125-0.1.

[0032] As a preferred embodiment of the present invention, a liquid injection hole is provided on the end wall, and the shell also satisfies the following relationship: 0.004≤z / (b+c)≤0.3, wherein z is the ratio of the area of ​​the liquid injection hole to that of the end wall.

[0033] As a preferred embodiment of the present invention, the range of z is 0.001-0.08.

[0034] As a preferred embodiment of the present invention, the steel further comprises C, Si, Mn, P, S and Fe.

[0035] In a second aspect of the present invention, the present invention provides a battery comprising the battery casing as described above.

[0036] In a third aspect of the present invention, the present invention provides an electrical device comprising the battery as described above.

[0037] The beneficial effects of the present invention are:

[0038] The present invention controls the relationship between the Ti and Nb contents and the shell height and end wall thickness, so that the steel with the Ti and Nb contents can meet the deep drawing processing performance of the battery shell, and the formed shell has good mechanical properties such as pressure bearing capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1This is a schematic diagram of the overall structure of the battery in Example 1;

[0040] Figure 2 This is a schematic diagram of the overall structure of the battery of Example 1 from another perspective;

[0041] Figure 3 This is a schematic structural diagram of the housing of Example 33;

[0042] Figure 4 for Figure 3 A local enlarged view of point A;

[0043] Figure 5 This is a schematic structural diagram of the housing of Example 38;

[0044] Figure 6 Schematic diagram of the overall structure of the battery of Example 45.

[0045] The icon marks are explained as follows:

[0046] 1-shell, 11-end wall, 12-end cover, 13-side wall, 2-weak part, 3-through hole, 4-liquid injection hole, 5-pole assembly. DETAILED DESCRIPTION

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0048] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0049] In the present invention, when referring to numerical ranges, unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Furthermore, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0050] An embodiment of the present invention provides a battery case, wherein the material of the case 1 includes steel, and the components of the steel include Ti, Nb and Cr, wherein the mass percentage of Cr is ≥16wt.% based on the total mass of the steel;

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

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

[0053] Wherein, h is the height of the housing 1, in mm;

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

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

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

[0057] The shape of the battery case 1 is mostly cylindrical, including cylindrical and prismatic. At the same time, the battery case 1 provided by the present invention is manufactured by a deep drawing process. During the deep drawing process, an opening surface is required for the punch to enter. The opening surface is generally one of the bottom surfaces of the cylindrical battery, and the other bottom surface is integrally formed with the side wall 13. In the present invention, the end wall 11 is defined as a surface integrally formed with the side wall 13, and the end cover 12 is provided at the opening surface. The end cover 12 is fixedly connected to the side wall 13, which can be welded, riveted, bonded, etc., without affecting the implementation of this solution.

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

[0059] During the deep drawing process, after the end wall 11 is formed and the side wall 13 is stretched, the end wall 11 serves as the stretching reference, and the end wall thickness d remains essentially unchanged. The initial thickness of the side wall 13 is the same as the end wall thickness d, and then decreases as the stretching proceeds. Therefore, as the height h of the shell 1 increases, the required deep drawing performance of the shell 1 must be correspondingly improved. This is especially true 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 side wall 13 is stretched more. This will result in the side wall 13 being formed thinner during the stretching process, and the strength requirements for preventing the shell 1 from breaking during the stretching process will be higher. This requires the shell 1 to have better deep drawing performance to prevent the shell 1 from hardening during the deep drawing process, localized force concentration, and fracture.

[0060] In the present invention, by controlling the titanium (Ti) and niobium (Nb) content, the deep-drawing properties of the steel can be regulated to a certain extent, thereby avoiding stress concentration during deep-drawing, which can lead to fracture and increased defective rates. This is particularly true when the end wall 11 is thin and the drawing height is high, i.e., when the shell 1 is tall, the steel needs to have excellent deep-drawing properties to avoid fracture of the shell 1 during the deep-drawing process.

[0061] However, high deep-drawing properties of steel mean that the steel is easily deformed, which may result in poor pressure-bearing capacity of the casing 1 after forming, leading to reduced battery safety. Furthermore, if the deep-drawing properties are poor, even if the casing 1 is barely formed, the mechanical properties of the formed casing 1 will be poor, and its safety performance will be difficult to guarantee. Therefore, it is necessary to balance the deep-drawing properties of the casing 1 during processing and the pressure-bearing performance after processing.

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

[0063] Therefore, the present invention ensures that the mass percentage b of Ti, the mass percentage c of Nb, the thickness d of the end wall 11, and the height h of the shell 1 satisfy 50≤(h / d) / (b+c)≤7000, so that the deep drawing properties of the steel can meet the size of the shell 1 to be processed, avoiding breakage during deep drawing processing and improving the processing yield. At the same time, the formed shell 1 also has better mechanical properties to ensure the safety of the battery.

[0064] In some embodiments of the present invention, 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 an interval 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 solution, the shell 1 that satisfies the above relationship can achieve a higher processing yield during the deep drawing process.

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

[0068] In some embodiments of the present invention, 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, 300mm, or it can be an interval range formed by any two of the above values, such as 50-270mm, 100-220mm, 80-300mm, etc.

[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 the present invention, the specific choice 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, 1.5mm, or it can be an interval 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 the present invention, 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 it can be an interval 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] Ti and Nb are both carbon and nitrogen stabilizing elements, combining with carbon and nitrogen to form NbC, NbN, TiC, and TiN, thereby increasing the strength of the steel. Furthermore, the precipitation of Ti carbides significantly enhances the steel's plasticity and impact toughness, ensuring excellent deep-drawing properties. It also inhibits the formation of chromium carbon and nitrogen oxides in the steel, thereby improving the stainless steel's resistance to intergranular corrosion. Trace amounts of Nb can enhance the steel's strength without affecting its plasticity or toughness. Nb carbides and oxides, by refining the grains, improve the steel's impact toughness and lower its brittle transition temperature.

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

[0078] Excessive Nb will lead to the formation of coarse Fe2Nb hard phase, reducing the elongation and deep drawing properties of the material, and too much NbN will also reduce the thermoplasticity of steel, so the Nb content is controlled within a certain range.

[0079] In some embodiments of the present invention, 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 an interval 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, the number of TiN inclusions is large and the size is large, 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 the present invention, 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 an interval 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] There is no limitation on the testing method for Ti, Nb, and Cr content, and those skilled in the art can test Ti, Nb, and Cr content using conventional methods, such as inductively coupled plasma method and X-ray fluorescence spectrometry.

[0084] Inductively coupled plasma method:

[0085] (1) Sample preparation: Stainless steel samples need to be properly pretreated, such as being dissolved in a specific acid solution to release the elements to be tested. 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 elements.

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

[0087] X-ray fluorescence spectrometry

[0088] (1) Sample preparation: First, the stainless steel sample needs to be properly processed to facilitate X-ray penetration and stimulate fluorescence. This may include cutting, grinding, polishing, etc. 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, stimulating the characteristic X-ray fluorescence of each element. The wavelength or energy characteristics of these fluorescence spectra correspond to the type of element, thus determining the elements contained in the sample.

[0090] (3) Spectral collection and analysis: The X-rays reflected from the sample surface and the emitted fluorescence spectrum are collected by a spectrometer. The type and content of the element can be determined by the position and intensity of the 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 then its performance and quality can be evaluated.

[0093] In one embodiment, the shell 1 further includes a side wall 13 , and the shell 1 also satisfies the following relationship: 0.5≤(f / d) / (b+c)≤5, wherein f is the thickness of the side wall 13 of the shell 1 , and the unit is mm.

[0094] Because the end wall 11 and side wall 13 are integrally formed through deep drawing, the greater the height of the housing 1, that is, the greater the stretch ratio of the side wall 13, the higher the deep drawing performance requirements for the steel. In particular, the change in the thickness of the end wall 11 during the deep drawing process is smaller than the change in the thickness of the side wall 13. That is, in the same housing 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 greater but the thickness of the side wall 13 is smaller, it means that the material stretch ratio of the side wall 13 is greater, making it difficult to form the housing as a whole.

[0095] In some embodiments of the present invention, the (f / d) / (b+c) can be selected from 0.5, 0.6, 0.8, 1, 2, 3, 4, 4.5, 5, or an interval 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 the present invention, 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, 1.15, 1.2mm, or it can be an interval 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 the present invention, the specific choice 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 an interval 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 vital role in its safety. For example, a short circuit or overcharge can cause thermal runaway within the battery cell, leading to a sudden increase in pressure or temperature. In this case, the pressure relief structure can release internal pressure and temperature to prevent explosion or fire in the battery cell. The specific form of the pressure relief structure is not limited; it is primarily used to provide timely pressure relief when thermal runaway occurs. The structure can include a separate explosion-proof disc, a hole in the housing 1, and the disc connected to the hole, or the explosion-proof structure can be formed directly by stamping or etching the housing 1.

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

[0103] When the pressure relief structure is releasing pressure, when the preset pressure is reached, the weak portion 2 on the explosion-proof plate explodes to achieve pressure relief, thereby ensuring the safety of the battery. The weak portion 2 can be a thinned portion formed by stamping or laser etching on the explosion-proof plate. The residual thickness of the thinned portion is the remaining thickness of the explosion-proof plate after thinning by stamping or laser etching. The residual thickness direction of the thinned portion is parallel to the thickness direction of the end wall 11, and the residual thickness of the thinned portion is less than the thickness of the end wall 11. The shape of the weak portion 2 can be set to imitate the explosion-proof plate, that is, a circle of punched-out annular thinned portions is set along the edge of the explosion-proof plate as the thinned portion. In this way, the weak portion 2 is set with a large area and is easier to explode. The thinned portion can also be an incomplete circle, but at least one unthinned area is retained on the annular thinned portion. In this way, after the pressure is released, the explosion-proof plate still has a connection to prevent the entire explosion-proof plate from flying out and causing safety hazards.

[0104] In this solution, the pressure relief structure is directly formed in the shell 1 by stamping or laser etching. Since the pressure relief structure is formed integrally with the shell 1, in order to ensure the processing rate, the strength of the shell 1, and the triggering pressure of the pressure relief structure, the size of the pressure relief structure needs to be compatible with the deep drawing ability of the shell 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. In order to avoid false triggering of the pressure relief structure, the residual thickness of the weak part 2 needs to be controlled. Since Ti and Nb are controlled within a specific range, the strength of the steel is improved, the size of m can be appropriately reduced, and the weak part 2 can be made thinner, so that the pressure relief structure can burst when the battery undergoes thermal runaway to protect the safety of the battery. At the same time, if m×(b+c) is too small, the Ti and Nb contents are too low, resulting in poor formability. The residual thickness m of the weak portion 2 is too small, resulting in low strength at the pressure relief structure and a tendency for accidental explosion. If m×(b+c) is too large, the Ti and Nb contents are too high, resulting in a low formability. The residual thickness m of the weak portion 2 is too large, which is not conducive to the pressure relief structure exploding and releasing heat when the battery experiences thermal runaway. Therefore, m×(b+c) needs to be controlled within an appropriate range.

[0105] When the end wall 11, side wall 13, and weak portion 2 and through hole 3 on the end wall 11 are integrally formed in the shell 1, it is necessary to consider the processing performance during the deep drawing process, the strength of the shell 1 after forming, and the bursting pressure of the pressure relief structure. The present invention defines the relationship and range between the residual thickness m of the weak portion 2 and the Ti and Nb contents, and the ratio z of the area of ​​the injection hole 4 to the area of ​​the end wall 11, and the Ti and Nb contents. While meeting the deep drawing processing requirements of the shell 1 height and end wall thickness, the Ti and Nb contents are further controlled so that when the end wall 11 is deep drawn to form the weak portion 2 and the through hole 3, the performance of the steel can meet the deep drawing process requirements and the shell 1 has sufficient strength after forming.

[0106] In some embodiments of the present invention, the m×(b+c) can be 0.004, 0.005, 0.006, 0.008, 0.01, 0.02, 0.04, 0.05, 0.08, 0.1, 0.11, 0.115, or 0.12, or it can be an interval range formed by any two of the above values, such as 0.004-0.08, 0.005-0.05, or 0.01-0.12.

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

[0108] In some embodiments of the present invention, the specific choice 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, 0.5mm, or it can be an interval 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 cover 12 on the other end relative to the end wall 11 , the end cover 12 is fixedly connected to the side wall 13 , and a through hole 3 for arranging the pole assembly 5 is provided on the end wall 11 or the end cover 12 .

[0110] In one embodiment, 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, wherein 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 provided on the end wall 11 of the housing 1 or on the end cover 12. In this embodiment, the through hole 3 is provided on the end wall 11. Since the end wall 11 is integrally formed with the housing 1 and the pressure relief structure is also provided on the end wall 11, in order to ensure the processing molding rate 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 capability of the housing 1. In this embodiment, the pole assembly 5 is electrically connected to the internal battery cell through the through hole 3. The cross-sectional area of ​​the pole affects the flow rate. Since the Ti and Nb contents are controlled within a certain range, the housing 1 is made stronger, thereby allowing for a larger through hole 3 to accommodate a larger pole assembly 5, thereby improving the flow rate. k / (b+c) needs to be within an appropriate range. If k / (b+c) is too small, the area of ​​through-hole 3 is small, resulting in a limited cross-sectional area of ​​the pole, insufficient current carrying capacity, and excessively high Ti and Nb contents, reducing the moldability of housing 1. If k / (b+c) is too large, the area of ​​through-hole 3 is relatively large while the Ti and Nb contents are relatively low. Due to the low Ti and Nb contents of end wall 11, housing 1 is inherently fragile. An excessively large area of ​​through-hole 3 further weakens end wall 11, further increasing the risk of deformation of housing 1. Therefore, k / (b+c) needs to be set within an appropriate range.

[0112] In some embodiments of the present invention, 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, 0.5, or it can be an interval 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 the present invention, 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, 0.1, or it can be an interval 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 further satisfies the following relationship: 0.004≤z / (b+c)≤0.3, wherein z is the ratio of the area of ​​the liquid injection hole 4 to that of the end wall 11 .

[0116] Because the Ti and Nb contents are controlled within a certain range, the strength of the shell 1 is increased, and an increase in the area of ​​the injection hole 4 will not weaken the overall strength of the end wall 11. Increased Ti and Nb contents improve corrosion resistance, and the strength of the end wall 11 is strengthened. The ratio z between the area of ​​the injection hole 4 and the end wall 11 can be increased, thereby improving injection efficiency. z / (b+c) needs to be within an appropriate range. If z / (b+c) is too small, the area of ​​the injection hole 4 is too small, affecting injection efficiency. Excessive Ti and Nb contents lead to a low forming rate for the shell 1. If z / (b+c) is too large, the area of ​​the injection hole 4 is too large, causing easy deformation of the end wall 11. Low Ti and Nb contents make the shell 1 susceptible to corrosion.

[0117] In some embodiments of the present invention, the specific selection of z / (b+c) can be 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 it can be an interval range formed by 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 the present invention, the specific selection of z can be 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 it can be an 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 follows Figure 3 As shown, the through hole 3 is provided on the end cover 12, and the injection hole 4 is provided on the end wall 11; it can also be as follows Figure 5 As shown, through-hole 3 is provided on end wall 11, and injection hole 4 is provided on end cap 12. Alternatively, through-hole 3 and injection hole 4 may be located at the same end of the housing. In this case, a hole is required in the terminal assembly to serve as the injection hole. Having through-hole 3 and injection hole 4 at each end of the housing facilitates battery assembly.

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

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

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

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

[0125] Inductively coupled plasma method:

[0126] (1) Sample preparation: Stainless steel samples need to be properly pretreated, such as being dissolved in a specific acid solution to release the elements to be tested. 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 elements.

[0127] (2) Analysis method: The analysis method of ICP-OES mainly includes the standard curve method and the internal standard method. The standard curve method draws a curve showing the relationship between the concentration of the standard solution and the emission intensity at the corresponding wavelength, and compares the emission intensity of the sample solution with the standard curve to obtain the content of each element in the sample. The internal standard method selects an element with similar chemical properties to the element to be measured and a constant content in the sample as the internal standard, and eliminates the influence of factors such as sample composition and experimental conditions by comparing the emission intensity ratio of the element to be measured and the internal standard element.

[0128] X-ray fluorescence spectrometry

[0129] (1) Sample preparation: First, the stainless steel sample needs to be properly processed to facilitate X-ray penetration and stimulate fluorescence. This may include cutting, grinding, polishing, etc. 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, stimulating the characteristic X-ray fluorescence of each element. The wavelength or energy characteristics of these fluorescence spectra correspond to the type of element, thus determining the elements contained in the sample.

[0131] (3) Spectral collection and analysis: The X-rays reflected from the sample surface and the emitted fluorescence spectrum are collected by a spectrometer. The type and content of the element can be determined by the position and intensity of the 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 then its performance and quality can be evaluated.

[0134] In the present invention, there is no particular limitation on the molding method of the housing 1 , and those skilled in the art can perform deep drawing molding on the housing 1 according to conventional technical means.

[0135] Exemplarily, in some embodiments, the battery preparation process is as follows:

[0136] 1. Preparation of the shell:

[0137] (1) Preparation of steel: smelting the molten steel to remove impurities, and fine-tuning the target chemical composition required by the shell 1 to obtain the molten steel with the above-mentioned composition, and then casting it to obtain a steel ingot;

[0138] (2) Preparation of blanks: rolling the steel ingots into coils, and then cutting the coils into plates of appropriate sizes;

[0139] (3) Deep drawing: The sheet is placed in a suitable die and fixed, and then the punch is pressed against the die with a certain force, and the drawing is repeated until the shell 1 is formed.

[0140] (4) Trimming: The excess material during the deep drawing process is removed and trimmed to ensure that the burrs and flatness of the cut meet the requirements.

[0141] 2. Preparation of positive electrode

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

[0143] 3. Preparation of negative electrode sheet

[0144] The negative electrode active material, conductive agent (SP), and binder are mixed in a specific mass ratio (97:1:1), deionized water is added as a solvent, and the mixture is stirred in a vacuum mixer until the mixture is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is evenly coated on both surfaces of the negative electrode current collector copper foil, dried at room temperature, and then transferred to an oven for further drying. The negative electrode sheets are then cold pressed and slit.

[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 diaphragm

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

[0149] 6. Preparation of lithium-ion batteries

[0150] The positive electrode sheet, separator, and negative electrode sheet are stacked in order, with the separator being placed between the positive electrode sheet and the negative electrode to serve as an isolation, and then wound to obtain a bare cell;

[0151] The battery cell is placed in the shell 1 (prepared as described above), and the end cover 12 and the shell 1 are connected together by laser welding; after drying, liquid is injected, chemical formation is carried out, and the volume is constant to obtain a prepared lithium-ion battery.

[0152] The present invention also provides a battery, comprising the above-mentioned battery casing.

[0153] The present invention also provides an electrical device comprising the battery as described above.

[0154] The present invention is further described below with specific embodiments:

[0155] Examples 1-17

[0156] Examples 1-17 respectively provide a shell 1, wherein the chemical composition of the shell 1 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: 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 rest is Fe.

[0160] like Figure 1-Figure 5 As shown in Table 1, 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 portion 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 liquid injection hole 4 to the end wall 11 where the liquid injection hole 4 is located are shown.

[0161] The battery is prepared as follows:

[0162] 1. Preparation of the shell

[0163] (1) Preparation of steel: smelting the molten steel to remove impurities, and fine-tuning the target chemical composition required by the shell 1 to obtain the molten steel with the above-mentioned composition, and then casting it to obtain a steel ingot;

[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 rolls to prepare shells 1 with different end wall thicknesses d. The coil is then cut into plates of appropriate sizes.

[0165] (3) Deep drawing: Place the sheet into a suitable die and fix it, then press the punch against the die 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 1661.06mm 2 .

[0166] (4) Trimming: The excess material during the deep drawing process is removed and trimmed to ensure that the burrs and flatness of the cut meet the requirements.

[0167] 2. Preparation of positive electrode

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

[0169] 3. Preparation of negative electrode sheet

[0170] The negative electrode active material, conductive agent (SP), and binder are mixed in a specific mass ratio (97:1:1), deionized water is added as a solvent, and the mixture is stirred in a vacuum mixer until the mixture is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is evenly coated on both surfaces of the negative electrode current collector copper foil, dried at room temperature, and then transferred to an oven for further drying. The negative electrode sheets are then cold pressed and slit.

[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 diaphragm

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

[0175] 6. Preparation of lithium-ion batteries

[0176] The positive electrode sheet, separator, and negative electrode sheet are stacked in order, with the separator being placed between the positive electrode sheet and the negative electrode to serve as an isolation, and then wound to obtain a bare cell;

[0177] The battery cell is placed in the shell 1 (prepared as described above), and the end cover 12 and the shell 1 are connected together by laser welding; after drying, liquid is injected, chemical formation is carried out, and the volume is constant to obtain a prepared lithium-ion battery.

[0178] X-ray fluorescence spectrometry

[0179] (1) Sample preparation: First, the stainless steel sample needs to be properly processed to facilitate X-ray penetration and stimulate fluorescence. This may include cutting, grinding, polishing, etc. 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, stimulating the characteristic X-ray fluorescence of each element. The wavelength or energy characteristics of these fluorescence spectra correspond to the type of element, thus determining the elements contained in the sample.

[0181] (3) Spectral collection and analysis: The X-rays reflected from the sample surface and the emitted fluorescence spectrum are collected by a spectrometer. The type and content of the element can be determined by the position and intensity of the 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 then its performance and quality can be evaluated.

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

[0185] The thickness of the end wall 11, the weak portion 2 and the side wall 13 are measured using an ultrasonic thickness gauge. During the measurement, three different positions of the test object are measured and an average value is obtained.

[0186] The measurement method of h is as follows:

[0187] The height of the housing 1 is measured using a laser height measuring instrument. During the measurement, three different positions of the test object are measured and the average value is taken.

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

[0189] Use a vernier caliper to measure the diameters of the through hole 3, the injection hole 4, and the end wall 11, and use the area formula of a circle to calculate the areas of the through hole 3, the injection hole 4, and the end wall 11, and finally calculate k and z.

[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 after deep drawing, the thickness d of the end wall 11, and the thickness f of the side wall 13 of the shell 1 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, 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 portion 2 after the explosion-proof valve is engraved and formed are shown in Table 3.

[0194] Examples 33-38

[0195] Examples 33-38 are similar to Example 1, except that Figure 5 As shown, the through hole 3 is provided on the end wall 11, and the injection hole 4 is provided on the end cover 12. The mass percentages of Ti and Nb are shown in Table 4. The height h of the housing 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 also shown in Table 4.

[0196] Examples 39-44

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

[0198] Example 45

[0199] Example 45 is similar to Example 1, except that Figure 6 As shown, 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 portion 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 liquid injection hole 4 to the end wall 11 where the liquid injection hole 4 is located are shown in Table 1.

[0200] The square shell is formed as follows:

[0201] (1) Preparation of steel: smelting the molten steel to remove impurities, and fine-tuning the target chemical composition required by the shell 1 to obtain the molten steel with the above-mentioned composition, and then casting it to obtain a steel ingot;

[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 rolls to prepare shells 1 with different end wall thicknesses d. The coil is then cut into plates of appropriate sizes.

[0203] (3) Deep drawing: Place the sheet into a suitable die and fix it, then press the punch against the die with a certain force, replace the square die and punch to perform a round-to-square operation, and repeat the drawing until the shell 1 is formed.

[0204] (4) Trimming: The excess material during the deep drawing process is removed and trimmed 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 shown in Table 1.

[0207] Table 1

[0208]

[0209] Table 2

[0210]

[0211] Table 3

[0212]

[0213] Table 4

[0214]

[0215] Table 5

[0216]

[0217] Performance testing:

[0218] The performance test methods of the above comparative examples and embodiments are as follows:

[0219] 1. Shell pressure bearing capacity test:

[0220] (1) Pressure holding test: First, seal the injection hole 4 with AB glue or structural glue; then install the shell 1 into the blasting / pressure test tooling, connect the inflation port to the blasting instrument, adjust to the pressure holding mode, and inflate the shell 1 from the mouth to the required pressure (such as 3Mpa, 4Mpa, 5Mpa), and maintain it for 30 seconds;

[0221] (2) Air tightness test: After the pressure test, the shell 1 is subjected to a helium test. If the leakage rate is ≤1×10-7Pa.m3 / s, the pressure resistance of the shell 1 is qualified under this air pressure.

[0222] 2. Deep drawing pass rate of shell

[0223] The shell 1 is deep drawn according to the above-mentioned preparation method of the shell 1 , and the deep drawing pass rate of 200 shells 1 is statistically prepared.

[0224] As can be seen from Table 1, in Examples 1-17 and 45, the shell 1 height h, end wall thickness d, Ti mass percentage b, and Nb mass percentage c all satisfying 50 ≤ (h / d) / (b + c) ≤ 7000. Compared with Comparative Examples 1-3, the shell 1 has a stronger pressure bearing capacity. Furthermore, local stress concentration during deep drawing is less likely to cause fracture, resulting in a higher deep drawing pass rate, making it more suitable for deep drawing processing. Furthermore, when the shell 1 satisfies 142 ≤ (h / d) / (b + c) ≤ 2000, the deep drawing pass rate is further improved. In particular, when the shell 1 also 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 pass rate of the shell 1 is even higher.

[0225] As can be seen from Table 2, Examples 18-26 all meet 142≤(h / d) / (b+c)≤2000. On this basis, considering that the thickness of the side wall 13 of the shell 1 needs to be less than that of the end wall 11 after deep drawing, when the thickness of the side wall 13 is significantly different from that of the end wall 11, that is, the side wall 13 is stretched relatively large, then the deep drawing performance requirements of the material are higher. From Examples 18-26, when 0.5≤f / (b+c)≤5 are met, the deep drawing pass rate of the shell 1 is higher. Furthermore, when the shell 1 also meets 0.1mm≤f≤1.2mm, the shell 1 is more suitable for deep drawing processing, its deep drawing pass rate is further improved, and the shell 1 after deep drawing processing has better pressure bearing capacity.

[0226] As can be seen from Table 3, Examples 27-32 all satisfy 142 ≤ (h / d) / (b + c) ≤ 2000. When the weak portion 2 of the battery pressure relief structure is formed integrally with the battery housing 1 through deep drawing, if 0.01 ≤ m × (b + c) ≤ 0.12 is satisfied, the weak portion 2 can be better deep-drawn, and the deep-drawing pass rate of the housing 1 is high. In particular, when the housing 1 also satisfies 0.05 mm ≤ m ≤ 0.12 mm, the housing 1 is more suitable for deep drawing, its deep-drawing pass rate is further improved, and the housing 1 after deep drawing has a stronger pressure-bearing capacity.

[0227] As can be seen from Table 4, Examples 33-38 all satisfy 142≤(h / d) / (b+c)≤2000. When it is necessary to provide a through hole 3 for the pole assembly 5 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 housing 1 after forming is safer.

[0228] As can be seen from Table 5, Examples 39-44 all satisfy 142≤(h / d) / (b+c)≤2000. When it is necessary to provide a liquid 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, and 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.

[0229] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A battery housing, wherein the housing (1) is made of steel and is characterized in that: The steel comprises Ti, Nb and Cr, wherein the mass percentage of Cr is ≥16wt.% based on the total mass of the steel; The housing (1) comprises a side wall (13) and an end wall (11) integrally formed with the side wall (13); The housing (1) satisfies the following relationship: 50≤(h / d) / (b+c)≤7000; The housing (1) further satisfies: the range of h is 40-270 mm, the range of d is 0.2-1.2 mm; the range of b+c is 0.2-0.8 wt.%; Wherein, h is the height of the housing (1), in mm; d is the thickness of the end wall (11), in mm; b is the mass percentage of Ti based on the total mass of steel, in wt.%; c is the mass percentage of Nb based on the total mass of the steel, in wt.%.

2. The battery case according to claim 1, wherein: The housing (1) satisfies the following relationship: 142≤(h / d) / (b+c)≤2000.

3. The battery case according to claim 1 or 2, characterized in that: The range of h is 50-200 mm.

4. The battery case according to claim 1 or 2, characterized in that: The range of d is 0.5-1.0 mm.

5. The battery case according to claim 1 or 2, characterized in that: The range of b+c is 0.25-0.5 wt.%.

6. The battery case according to claim 5, characterized in that The range of b is 0.05-0.2 wt.%.

7. The battery case according to claim 5, characterized in that The range of c is 0.17-0.5 wt.%.

8. The battery case according to claim 1 or 2, characterized in that: The shell (1) also satisfies the following relationship: 0.5≤(f / d) / (b+c)≤5, wherein f is the thickness of the side wall (13) of the shell (1), and its unit is mm.

9. The battery case according to claim 8, characterized in that The range of f is 0.1-1.2 mm.

10. The battery case according to claim 8, characterized in that The range of d is 0.3-1.2 mm.

11. The battery case according to claim 1, wherein: A pressure relief structure is provided on the end wall (11) of the housing (1).

12. The battery case according to claim 11, characterized in that: The pressure relief structure includes a weak portion (2), and the shell (1) also satisfies the following relationship: 0.004≤m×(b+c)≤0.12, wherein m is the residual thickness of the weak portion (2), in units of mm.

13. The battery case according to claim 12, characterized in that: The range of m is 0.01-0.5 mm.

14. The battery case according to claim 1 or 11, characterized in that: An end cover (12) is provided on the other end of the housing (1) relative to the end wall (11); the end cover (12) is fixedly connected to the side wall (13); and a through hole (3) for arranging a pole assembly (5) is provided on the end wall (11) or the end cover (12).

15. The battery case according to claim 14, characterized in that: 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, wherein 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.

16. The battery case according to claim 15, characterized in that The range of k is 0.00125-0.

1.

17. The battery case according to claim 1, wherein: 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, wherein z is the ratio of the area of ​​the liquid injection hole (4) to that of the end wall (11).

18. The battery case according to claim 17, characterized in that The range of z is 0.001-0.

08.

19. The battery case according to claim 1, wherein: The steel also includes C, Si, Mn, P, S and Fe.

20. A battery, characterized in that: Comprising the battery casing according to any one of claims 1-19.

21. An electrical device, characterized in that: Comprising the battery of claim 20.

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