Battery and electrical device with the battery

Abstract

A battery comprising a housing (1) and a cell (2) provided in the housing (1), the material of the housing (1) comprising steel, characterized in that the composition of the steel comprises Ti, Nb, and Cr, the mass fraction of Cr being ≥ 16 wt.% based on the total mass of the steel; the housing (1) comprises a side wall (13) and an end wall, the end wall having a first end wall (11) and a second end wall (12), each arranged at both ends of the side wall (13), and the two ends of the cell (2) having a first end surface near the first end wall (11) and a second end surface near the second end wall (12); the first end wall (11) and the side wall (13) being integrally formed; wherein the housing (1) satisfies the following relationship: 0.15 ≤ a / [d × (b + c)] ≤ 300; where “a” is the sum of the distance of the first end face to the first end wall (11) and the distance of the second end face to the second end wall (12) in mm; “d” is the thickness of the first end wall (11) in mm; “b” is the mass fraction of Ti relative to the total mass of the steel, in wt%; “c” is the mass fraction of Nb, based on the total mass of the steel, in wt.%.

Description

TECHNICAL FIELD

[0001] The present invention relates to the technical field of batteries, and more particularly to a battery and an electrical device containing this battery. BACKGROUND

[0002] A battery casing not only provides a physical protective barrier for a battery, preventing the battery's internal components from being affected by the external environment (such as moisture, dust, vibration, etc.), but also ensures the battery's safety during use. The battery casing is typically made of materials with specific strength, corrosion resistance, and insulation properties to meet the battery's operating requirements in various environments. Battery safety is especially important for power batteries used in new energy vehicles.

[0003] Currently, metal deep drawing is one of the most important forming processes for battery casings. This process utilizes the plasticity of metal materials to further stretch and deform or reshape the materials under specific pressure conditions until they assume the desired shape. Due to its advantages such as high processing efficiency, low cost, and stable quality, deep drawing is widely used in automotive, aerospace, electronics, and other fields.

[0004] To ensure metal processing performance during the deep drawing process, the material must have a certain degree of ductility and plastic formability. However, the casing becomes thinner after deep drawing, and the high plastic formability of the material increases the risk of casing deformation after forming, which compromises battery safety. Especially when the battery casing is manufactured using deep drawing processes, the cells inside the casing expand during the charging and discharging process, resulting in a higher risk of casing deformation.

[0005] Increasing the strength of the case by increasing the thickness of the battery case may increase the cost of the battery, and increasing the weight of the battery reduces the energy density of the battery. SUMMARY OF THE INVENTION

[0006] The present invention aims to provide a battery and an electrical device including this battery to overcome the drawbacks of the prior art that it is difficult to reconcile the three performances of case forming performance, the ability of the case to resist the risk of deformation due to cell expansion, and the energy density of the battery.

[0007] To achieve the above-mentioned object, according to the first aspect of the present invention, there is provided a battery comprising a casing and a cell provided in the casing, wherein the material of the casing comprises steel, the composition of the steel comprising Ti, Nb and Cr, wherein, based on the total mass of the steel, the mass fraction of Cr is ≥16 wt%; wherein the casing has a side wall and an end wall, the end wall has a first end wall and a second end wall, each disposed at both ends of the side wall, and the two ends of the cell have a first end surface near the first end wall and a second end surface near the second end wall; wherein the first end wall and the side wall are integrally formed; where the housing satisfies the following relationship: 0.15 ≤ a / [d ×(b + c)] ≤ 300; where “a” is the sum of the distance of the first end face to the first end wall and the distance of the second end face to the second end wall in mm; “d” is the thickness of the first end wall in mm; ‘b’ is the mass fraction of Ti relative to the total mass of the steel, in wt.%; “c” is the mass fraction of Nb, based on the total mass of the steel, in wt.%.

[0008] As a preferred embodiment of the present invention, the housing satisfies the following relationship: 1 ≤ a / [d × (b + c)] ≤ 200.

[0009] As a preferred embodiment of the present invention, the range of “b+c” is between 0.2 and 0.8 wt%.

[0010] As a preferred embodiment of the present invention, the range of “b+c” is between 0.25 and 0.5 wt%.

[0011] As a preferred embodiment of the present invention, the range of “b” is between 0.05 and 0.2 wt%.

[0012] As a preferred embodiment of the present invention, the range of “c” is between 0.17 and 0.5 wt%.

[0013] As a preferred embodiment of the present invention, the range of “d” is between 0.15 and 1.2 mm.

[0014] As a preferred embodiment of the present invention, the range of “a” is between 0.1 and 10 mm.

[0015] As a preferred embodiment of the present invention, the battery is a cylindrical battery.

[0016] As a preferred embodiment of the present invention, the range of “a” is between 0.5 and 10 mm.

[0017] As a preferred embodiment of the present invention, the cell is provided with a center hole of the cell winding or core hole, and the battery satisfies the following relationship: 0.4 < S × a ≤ 600; where “S” is the area of ​​the center hole of the cell winding in mm 2 is.

[0018] As a preferred embodiment of the present invention, the battery is a quadrangular prismatic battery.

[0019] As a preferred embodiment of the present invention, the range of “a” is 0.1 to 8 mm.

[0020] As a preferred embodiment of the present invention, the range of “b+c” is 0.2 to 0.7 wt% when the aspect ratio of the casing is not less than 2.

[0021] As a preferred embodiment of the present invention, the cell comprises a positive tab and a negative tab, wherein the positive tab or the negative tab is electrically connected to the housing and the mass fraction of Cr is 16 to 30 wt%.

[0022] As a preferred embodiment of the present invention, the positive tab and the negative tab are both provided on the first end face or the second end face of the cell, and the range of “a” is 0.5-10 mm.

[0023] As a preferred embodiment of the present invention, the positive tab and the negative tab are provided on the first end face and the second end face of the cell, respectively, and the range of “a” is 0.2 to 8 mm.

[0024] An electrical device containing a battery as described above. The advantageous effects of the present invention are:

[0025] According to the present invention, by controlling the sum "a" of the distances between the end faces at both ends of the case and the end walls at both ends of the cell, the thickness "d" of the first end wall, and the relationship between the contents "b" and "c" of Ti and Nb, it is possible to balance the processing performance of the case during the molding process and the ability of the case to resist the risk of deformation due to cell expansion. This allows the case to be easily processed by deep drawing and has a certain degree of deformation resistance after the case is molded, thereby preventing deformation of the case due to cell expansion during charging and discharging and ensuring battery safety.At the same time, the present invention can also ensure that the energy density of the battery is not too low and avoid a reduction in the energy density of the battery due to an excessively large “a” or “d” to reduce the risk of deformation of the battery case. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram showing the overall structure of the housing according to Example 1 of the present invention; Fig. 2 is a schematic diagram of the internal structure of the housing according to Example 1 of the present invention; Fig. 3 is a schematic diagram of the overall structure of the housing according to Example 29 of the present invention. In the figures:

[0026] 1 - housing, 11 - first end wall, 12 - second end wall, 13 - side wall, 2 - cell, 21 - center hole of the cell winding. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] In order to more clearly illustrate the objects, technical solutions, and advantages of the embodiments of the present invention, the technical solutions according to the embodiments of the present invention are described clearly and completely below. It should be understood that the described embodiments represent a part of the embodiments of the present invention, not all embodiments. Starting from the embodiments of the present invention, all other embodiments that a person skilled in the art can achieve without creative effort fall within the scope of the present invention.

[0028] In the present invention, the technical features defined in an open restriction include a closed technical solution consisting of the stated features and also an open technical solution including the stated features.

[0029] When a numerical interval is referred to in the present invention, unless otherwise stated, the above numerical interval is considered continuous and includes the minimum and maximum values ​​of the defined range, as well as any value between those minimum and maximum values. When a range refers to an integer, any integer between the minimum and maximum values ​​of the range is included. Furthermore, when multiple ranges are provided to describe features or properties, the ranges may be combined. In other words, unless otherwise stated, all ranges disclosed herein are to be understood as including all subranges contained therein.

[0030] The reagents or instruments used in the present invention, the manufacturers of which are not specified, are all commercially available products.

[0031] One embodiment of the present invention relates to a battery comprising a casing 1 and a cell 2 provided in the casing 1. The material of the casing 1 comprises steel, the composition of the steel 1 comprising Ti, Nb and Cr, the mass fraction of Cr being ≥ 16 wt.% based on the total mass of the steel. The casing 1 comprises a side wall 13 and an end wall, the end wall comprising a first end wall 11 and a second end wall 12, which are respectively arranged at both ends of the side wall. The two ends of the cell 2 comprise a first end surface near the first end wall 11 and a second end surface near the second end wall 12, and the first end wall 11 and the side wall 13 are integrally formed.

[0032] The housing satisfies the following relationship: 0.15 ≤ a / [d × (b + c)] ≤ 300; where “a” is the sum of the distance of the first end face to the first end wall 11 and the distance of the second end face to the second end wall 12 in mm; “d” is the thickness of the first end wall 11 in mm; ‘b’ is the mass fraction of Ti relative to the total mass of the steel, in wt.%; “c” is the mass fraction of Nb, based on the total mass of the steel, in wt.%.

[0033] The battery casing 1 must have a certain corrosion resistance. Therefore, the corrosion resistance of the steel casing 1 is improved by a Cr mass fraction of ≥ 16 wt%. However, as the Cr mass fraction increases, the hardness of the casing 1 increases, while the toughness and plasticity decrease, and the deep drawing performance deteriorates. This increases the risk of breakage of the casing 1 during deep drawing, leading to a reduction in the manufacturing yield and performance of the casing 1. Therefore, the deep drawing performance of steel is improved by adding Ti and Nb to ensure rapid forming and yield of the casing 1.

[0034] Since the housing 1 is made of steel and is formed by deep drawing, its Ti (titanium) b and Nb (niobium) c content affect the plastic formability of the housing 1. If the total content of Ti and Nb is too low, the plastic formability of the steel is poor, and the housing 1 is easily damaged during stamping, resulting in an increase in the defect rate. However, the Ti and Nb content cannot be too high. Although increasing the Ti and Nb content within a certain range improves the plastic formability, which is beneficial for the deep drawing forming of the housing 1, it also increases the risk of deformation of the housing 1 due to stress. In particular, the thinner the wall thickness "d" of the end wall of the housing 1 after forming, the greater the risk of deformation. In addition, if the Ti and Nb content is too high, they form coarse particles with the iron element, thereby reducing the forming performance of the steel.

[0035] The cell 2 expands during charging and discharging, increasing the risk of deformation of the case 1. In particular, the end wall of the case 1 usually integrates various components such as concentrated components, and the expansion of the end wall greatly increases the safety risk of the battery. In order to reduce or avoid deformation of the case 1 caused by the expansion of the cell 2, the sum "a" of the distance between the first end surface of the cell 2 and the first end wall 11 of the case 1 and the distance between the second end surface of the cell 2 and the second end wall 12 of the case 1, that is, the total distance between the two ends of the cell 2 and the inner side wall 13 of the case 1. If "a" is too small, the case 1 is easily deformed when the cell 2 expands. If "a" is too large, the internal space utilization of the case 1 is low, thereby reducing the energy density of the battery.The cell 2 comprises a cell body 2 and a tab. The first end surface and the second end surface refer to the end surface of the cell body 2. The tab is provided on the end surface of the cell body 2. Therefore, the distance between the first end surface and the first end wall 11 refers to the distance from the cell body 2 to the first end wall 11, not the distance from the tab to the first end wall 11. The distance from the second end surface to the second end wall 12 also refers to the distance from the cell body 2 to the second end wall 12.

[0036] Therefore, if "a" is relatively large, there will be a large space between the cell 2 and the end wall of the case 1. In this case, the case 1 is not easily deformed by the expansion of the cell 2, so "b+c" can also be relatively large to achieve better plastic formability and improve deep drawing performance. However, "a" cannot be too large to avoid deformation of the case 1 due to the expansion of the cell 2, because too large "a" will lead to a decrease in the volume energy density of the battery.

[0037] The first end wall 11 is formed integrally with the side wall 13. When the case 1 is formed by deep drawing, an opening is required for the punch to enter. The opening is usually one of the end walls of the battery, which is formed integrally with the side wall 13. The other end wall is formed separately and firmly connected to the side wall 13 by welding, riveting, gluing, etc. In the present invention, the first end wall 11 refers to the end wall formed integrally with the side wall 13, and the second end wall 12 refers to the end wall formed separately and firmly connected to the side wall 13. Since the first end wall 11 and the side wall 13 are integrally formed by deep drawing, the thickness that can be formed of the first end wall 11 relates to the deep drawing performance of steel.At the same time, the greater the thickness of the first end wall 11, the greater the resistance to deformation, and the lower the risk of breakage during the molding process of the housing 1. Therefore, the present invention limits the thickness of the first end wall 11 instead of the thickness of the second end wall 12.

[0038] If "d" is larger, i.e., the thickness of the first end wall 11 is greater, the risk of deformation of the casing 1 is lower, the stretch ratio of the casing 1 is smaller, and the risk of breakage during the forming process is reduced. In this case, "a" and "b+c" can be relatively reduced, but "d" cannot be too large. If "d" is too large, the mass energy density of the battery will be too high, and the cost will be too high.

[0039] If "d" is smaller, i.e., the wall thickness of the first end wall 11 is smaller, the stretch ratio of the housing 1 is larger, which increases the risk of breakage during the molding process. To improve the molding performance of the housing 1, "b+c" should be increased accordingly. However, this increases the risk of deformation of the housing 1. Therefore, to reduce the risk of deformation of the housing 1, "a" should also be increased accordingly.

[0040] In summary, by the sum "a" of the distance from the first end surface to the first end wall 11 and the distance from the second end surface to the second end wall 12, the thickness "d" of the first end wall 11, the mass fraction "b" of Ti, and the mass fraction "c" of Nb satisfying the following conditions: 0.15 ≤ a / [d × (b + c)] ≤ 300, the casing 1 can have the plastic deformation capacity required for deep drawing processing, while simultaneously reducing the risk of deformation of the casing 1 after forming. In this way, the risk of deformation of the casing 1 due to the expansion of the cell 2 can be avoided while ensuring that the energy density of the battery is not too low.

[0041] In one embodiment, the first end wall 11 is formed integrally with the housing 1, and the second end wall 12 may be a separate cover plate. The second end wall 12 may be connected to the circumferential side wall 13 of the housing 1 by welding, riveting, gluing, etc. The material of the cover plate may be the same as that of the side wall 13 and the first end wall 11.

[0042] In some embodiments of the present invention, a / [d × (b + c)] may be specifically selected from 0.15, 0.2, 0.3, 0.5, 1, 2, 5, 8, 10, 20, 30, 50, 75, 100, 120, 150, 180, 200, 220, 250, 270, 280, 300, or an interval range formed by any two of the above values, e.g., 1-200, 0.2-120, 2-220, etc.

[0043] The present invention does not limit the testing method for the Ti, Nb, and Cr content, and a person skilled in the art can test the Ti, Nb, and Cr content according to conventional methods such as the inductively coupled plasma method, X-ray fluorescence spectrometry, and the like. The method for measuring “a” is as follows:

[0044] It measures the height of cell 2, i.e., the maximum distance a1 from the first end face to the second end face. It measures the height within housing 1, i.e., the minimum distance a2 from the first end wall to the second end wall. Then, a=a2-a1. To reduce errors, it can measure a1 and a2 multiple times and determine their average values. The procedure for measuring “d” is as follows:

[0045] It measures the thickness of the first end wall 11 using an ultrasonic thickness gauge. To reduce errors, several different positions of the first end wall 11 of each housing 1 are measured during the measurement, and the average value is taken as the thickness "d" of the first end wall 11 of the housing 1. The present invention does not limit the testing methods for Ti, Nb, and Cr content. Those skilled in the art can test the Ti, Nb, and Cr content using conventional methods. For example, inductively coupled plasma spectrometry, X-ray fluorescence spectrometry, or other testing methods have no influence on the implementation of the present invention.

[0046] Inductively coupled plasma process: (1) Sample preparation: Stainless steel samples must be properly pretreated, e.g., by dissolving them in a special acid solution to release the elements to be measured. For example, aqua regia can be used to dissolve the sample, or a special acid mixture can be used for digestion to ensure effective element release. (2) Analysis method: ICP-OES analysis methods mainly include the standard curve method and the internal standard method. In the standard curve method, the relationship between the concentration of the standard solution and the emission intensity at the corresponding wavelength is recorded, and the emission intensity of the sample solution is compared with the standard curve to determine the content of each element in the sample. In the internal standard method, an element with similar chemical properties to the element to be measured and with a constant content in the sample is selected 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. X-ray fluorescence spectrometry (1) Sample preparation: First, the stainless steel sample must be appropriately prepared to facilitate X-ray penetration and stimulate fluorescence. This may require cutting, grinding, polishing, and other steps to ensure the sample surface is flat and free of contaminants. (2) X-ray excitation: The sample surface is irradiated with high-energy X-rays to excite the characteristic X-ray fluorescence of each element. The wavelength or energy characteristics of these fluorescence spectra correspond to the nature of the elements, allowing the elements contained in the sample to be determined. (3) Spectrum acquisition and analysis: The X-rays reflected from the sample surface and the emitted fluorescence spectra are recorded by a spectrometer. The type and content of elements can be determined based on the position and intensity of the characteristic spectral lines. (4) Matrix effect correction: Due to the interaction between different elements in stainless steel (matrix effect), the collected spectral data must be corrected to eliminate the influence of this interaction on the analysis results and improve the accuracy of the analysis. (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.

[0047] In one embodiment, the housing 1 satisfies the following relationship: 1 ≤ a / [d × (b + c)] ≤ 200.

[0048] In the present embodiment, the casing 1 satisfying the above relationship not only satisfies the plastic deformation capacity required for deep drawing processing, but also has a smaller degree of deformation of the casing 1 caused by the expansion of the cell 2.

[0049] In one embodiment, the range of “b+c” is between 0.2 and 0.8 wt%.

[0050] In some embodiments of the present invention, the specific selection of "b+c" may be 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, or it may be the interval range formed by any two of the above values, such as 0.25-0.5, 0.3-0.7, 0.2-0.6, etc.

[0051] In one embodiment, the range of “b” is 0.05 to 0.2 wt%.

[0052] In some embodiments of the present invention, the specific selection of "b" may be 0.05, 0.06, 0.07, 0.08, 0.1, 0.12, 0.15, 0.17, 0.18, 0.19, 0.2, or an interval range formed by any two of the above values, such as 0.05 to 0.15, 0.07 to 0.2, 0.1 to 0.2, etc.

[0053] In one embodiment, the range of “c” is 0.17 to 0.5 wt%.

[0054] In some embodiments of the present invention, the specific selection of "c" may be 0.17, 0.18, 0.19, 0.2, 0.22, 0.25, 0.28, 0.3, 0.35, 0.4, 0.45, 0.48, 0.5, or an interval range formed by any two of the above values, for example, 0.17 to 0.4, 0.2 to 0.4, 0.25 to 0.5, etc.

[0055] Ti and Nb are both stabilizing elements of carbon and nitrogen, and can combine with carbon and nitrogen to form TiC, TiN, or NbC, NbN. They can inhibit the formation of chromium carbon and nitride in steel and improve the intergranular corrosion resistance of stainless steel. At the same time, Ti and Nb are both forming elements of ferrite. An appropriate amount of Ti in steel can refine the ferrite weld structure and improve the plasticity and formability of the weld. However, excessive addition of Ti reduces the formability of the material. At the same time, Ti mainly exists in the form of precipitate phases such as TiN, and the solid solubility product of TiN is very low, so it begins to precipitate before solidification. This uneven nucleation point promotes the excessive proportion of equiaxed crystals in the solidification structure, thereby achieving good deep drawing properties.Solid Nb solution can promote the formation of a γ+α two-phase texture in steel, and a small amount of this texture contributes to improving deep drawing performance. However, too high a Nb content leads to the formation of a hard Fe2Nb phase in the steel, which reduces the material's ductility and deep drawing performance. Too much nitride (NbN), formed by Nb and nitrogen, also reduces the hot plasticity of steel.

[0056] The Ti mass fraction is the percentage of Ti mass relative to the total mass of the steel. The Nb mass fraction is the percentage of Nb mass relative to the total mass of the steel.

[0057] In one version, the range of “d” is between 0.15 and 1.2 mm.

[0058] In some embodiments of the present invention, the specific selection of "d" may be 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.05, 1.1, 1.15, 1.2, or an interval range formed by any two of the above values, such as 0.2-1.0, 0.15-0.8, 0.5-1.2, etc.

[0059] In one version, the range of “a” is 0.1-10 mm.

[0060] In some embodiments of the present invention, "a" may be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0 or any two of the above values, such as 0.2-0.8, 0.5-1.0, 0.35-0.85, etc.

[0061] In one version, the battery is a cylindrical battery.

[0062] In one version, the range of “a” is 0.5 to 10 mm.

[0063] The cell 2 expands during charging and discharging, thereby exerting force on the casing 1, causing the casing 1 to deform. When the casing 1 is a cylinder, the expansion force of the cell 2 on the circumference of the cylindrical casing 1 cancels each other out, so the impact force on the circumference of the casing 1 is relatively small, and the risk of lateral deformation of the cylindrical casing 1 is relatively low. The expansion of the end surface of the cell 2 has a greater impact on the end wall of the casing 1, and the risk of deformation of the end wall of the cylindrical casing 1 is greater. Therefore, in order to reduce the risk of deformation of the casing 1, for the cylindrical casing 1, the value of "a" can be appropriately increased so that a sufficient gap remains between the cell 2 and the casing 1 to reduce the deformation rate of the end wall of the casing 1 due to the expansion of the cell 2.Therefore, when the housing 1 is a cylinder, the lower limit of the preferable range of "a" is increased accordingly. The range of "a" in the present embodiment is 0.5 to 10 mm.

[0064] In one embodiment, the cell 2 is provided with a center hole of the cell winding 21, and the battery satisfies the following relationship: 0.4 ≤ S × a ≤ 600;

[0065] Where “S” is the area of ​​the center hole of the cell winding 21 in mm 2 is.

[0066] The cell 2 includes a positive electrode, a negative electrode, and a separator. The separator is provided between the positive electrode and the negative electrode. The positive electrode, the negative electrode, and the separator form the cell 2 by winding or stacking. The positive electrode includes a cathodic current collector and a cathodic active substance layer. The negative electrode includes an anodic current collector and an anodic active substance layer. The present invention does not limit the material of the cathodic current collector as long as it is conductive and does not cause adverse chemical changes in the battery. For example, stainless steel, aluminum, nickel, titanium, burnt carbon, or aluminum or stainless steel with a surface treatment of carbon, nickel, titanium, silver, etc. can be used.The current collector may also be a composite current collector comprising a polymer interlayer and a conductive layer provided on both sides of the interlayer. The active substance layer is provided on the surface of the conductive layer. Furthermore, the anodic current collector may be made of copper, stainless steel, nickel, titanium, etc. In a specific embodiment, the cathodic current collector may be made of aluminum, and the anodic current collector may be made of copper.

[0067] The active cathodic substance layer includes active cathodic materials, including ternary nickel-cobalt-manganese materials, lithium iron phosphate materials, lithium iron manganese phosphate materials, etc.; the active anodic substance layer includes active anodic materials, including artificial graphite, natural graphite, silicon-based materials, etc.

[0068] Cell 2 is wound using a winding needle as a support. After winding is completed, the winding needle is withdrawn from cell 2. By withdrawing the winding needle, a center hole of the cell winding 21, or core hole 21, is formed in the center of cell 2. The center hole of the cell winding 21 can be used as a gas storage space to reduce the expansion rate of cell 2 and thus reduce the deformation rate of the end wall of the case 1 caused by the expansion of cell 2. Therefore, the larger the center hole of the cell winding 21, the more gas storage space there is, and the lower the expansion rate of the case 1 caused by the expansion of cell 2. In this case, the value of "a" can be reduced accordingly, thereby improving the space utilization of the case 1 and increasing the energy density of the battery.

[0069] In one version, the battery is a square-prismatic battery.

[0070] If the battery is a quadrangular prismatic battery, the battery case 1 and the cell 2 both have the shape of a quadrangular prism.

[0071] In one version, the range of “a” is between 0.1 and 8 mm.

[0072] When the housing 1 has the shape of a quadrangular prism, the area of ​​the side wall 13 of the housing 1 is generally different from that of the end walls at both ends, especially when the end wall is rectangular. The side wall 13 comprises two opposite first side walls and two opposite second side walls, wherein the area of ​​the first side wall is larger than the area of ​​the second side wall. At the same time, the cell 2 also has the shape of a quadrangular prism. The cell 2 also comprises two opposite first side surfaces and two opposite second side surfaces. The position of the cell 2 in the housing 1 is the same. The first side wall is arranged opposite the first side surface, and the second side wall is arranged opposite the second side surface.During the charging and discharging process of cell 2, the first side surface of cell 2 with the largest area expands more and exerts a greater force on the first side wall of the housing 1. Therefore, the risk of deformation of the first side wall is higher.

[0073] Therefore, when the housing 1 is in the shape of a quadrangular prism, the expansion of the housing 1 is not uniform, and the side of the housing 1 with the largest area expands more. The above-mentioned side is typically the side wall 13 of the housing 1, which has little influence on the expansion of the end wall. Therefore, the preferred range of "a" can be reduced accordingly. The range of "a" in the present embodiment is 0.1 to 8 mm.

[0074] In one embodiment, the range of “b+c” is 0.2 to 0.7 wt% when the aspect ratio of the housing 1 is not less than 2.

[0075] When the shape of the case 1 is a quadrangular prism, the length and width of the case 1 correspond to the lengths of the long and short sides of the end wall of the case 1. When the case 1 is subjected to deep drawing, this involves a process of converting a circle into a square. In this process, the larger the aspect ratio of the case 1, the better the plastic formability required for its deep drawing. However, the risk of deformation of the case 1 due to the expansion of the cell 2 is higher, and the deformation resistance of the case 1 must be considered. Therefore, when the aspect ratio of the case 1 is not less than 2, the preferred range for "b+c" is 0.2 to 0.7 wt%.

[0076] In one embodiment, cell 2 comprises a positive tab and a negative tab. The positive tab or the negative tab is electrically connected to the housing 1. The mass fraction of Cr is 16 to 30 wt.%.

[0077] For the forming method of the positive tab and the negative tab, the positive electrode and the negative electrode specifically comprise a current collector and an active substance layer, wherein the active substance layer is applied to the current collector. The positive tab and the negative tab may be formed by cutting the current collector; they may also be separate conductive parts and electrically connected to the current collector; or they may be formed by other methods that do not affect the implementation of the embodiments.

[0078] The battery also includes a terminal post assembly provided on the housing 1. Two terminal post assemblies may be provided, each connected to the positive tab and the negative tab. However, in the present embodiment, one terminal post assembly is provided, located on the end wall of the housing 1. One of the positive tabs and the negative tab are connected to the housing 1. One of the positive tabs and the negative tab of the battery cell 2 are connected to the housing 1, and the other is connected to the terminal post assembly.For example, the positive tab is connected to the housing 1 so that the housing 1 is positively charged, and the terminal post assembly is connected to the negative tab of the battery so that the terminal post assembly is negatively charged; or the positive tab is connected to the terminal post assembly of the battery so that the terminal post assembly is positively charged, and the negative tab is connected to the housing 1 so that the housing 1 is negatively charged.

[0079] The housing 1 is connected to the positive tab or the negative tab, so that the housing 1 serves as the electrode output end. This, on the one hand, increases the area of ​​the housing 1 used for electrical connection, which can increase the overcurrent range. On the other hand, the space of an electrode assembly is saved, so that sufficient space is available for the installation of the remaining motor assembly, thereby simplifying the battery structure and providing space for the arrangement of other components such as the battery bus. The connection between the positive tab or the negative tab and the housing 1 is an electrical connection.It can be directly connected by welding or the like, or the positive tab or the negative tab can be connected in front of the current collecting plate, and the current collecting plate can be welded to the housing 1 to achieve an indirect connection, thereby improving the welding effect through the indirect connection. Other connection methods are also possible and do not affect the implementation of the present embodiment.

[0080] The positive or negative tab is connected to the casing 1, and the casing 1 serves as the electrical connection of the cathode or anode. In this case, the risk of electrochemical corrosion of the casing 1 increases. To improve the electrochemical corrosion resistance of the casing 1, the Cr content must be increased. Cr is the main element that determines the corrosion resistance of stainless steel. It can increase the matrix electrode potential and thereby significantly improve the corrosion resistance of steel. In addition, Cr, as the main component of the oxide layer, contributes to the formation of a more stable oxide layer and improves oxidation resistance at high temperatures. However, after increasing the Cr content, the hardness of the casing 1 increases, the plastic deformability of the casing 1 during forming deteriorates, and the processing performance decreases.If the processing performance of the housing 1 is to be improved, the content of Ti and Nb must be increased, which in turn increases the risk of deformation of the housing 1.

[0081] Therefore, the mass fraction of Cr is limited to 16 to 30 wt%, which not only ensures the corrosion resistance of the housing 1 and reduces the risk of deformation, but also avoids the increased risk of breakage during the forming process of the housing 1, which would lead to a reduction in the manufacturing yield of the housing 1.

[0082] In one embodiment, the positive tab and the negative tab are both provided on the first end face or the second end face of the cell 2, and the range of “a” is 0.5 to 10 mm.

[0083] Since the positive tab and the negative tab are provided at the same end of the cell 2, heat is concentrated, resulting in an increased risk of deformation of the end wall of the housing 1, and the range of a can be increased accordingly. Therefore, the preferred range of "a" in the present embodiment is 0.5 to 10 mm.

[0084] In one embodiment, the positive tab and the negative tab are provided on the first end face and the second end face of the cell 2, respectively, and the range of “a” is 0.2 to 8 mm.

[0085] The positive tab and the negative tab are provided on the first end surface and the second end surface of the cell 2, respectively, so that heat is dissipated, the risk of deformation of the end wall of the housing 1 is reduced, and the range of "a" can be reduced accordingly. Therefore, the preferable range of "a" in the present embodiment is 0.2 to 8 mm. In the present embodiment, the positive tab may be provided on the first end surface and the negative tab on the second end surface; or the positive tab may be provided on the second end surface and the negative tab on the first end surface. In some versions the steel includes:

[0086] Fe and the following composition in mass fractions (relative to the total mass of the steel): C: greater than 0 and less than 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 unavoidable impurities of 0.5%.

[0087] A further embodiment of the present invention also provides an electrical device comprising the battery described above. In some embodiments, for example, the process for manufacturing the battery is as follows: 1. Preparation or manufacture of the housing: (1) Steel preparation: Melt the steel to remove impurities and precisely adjust the chemical composition required for the shell 1. After obtaining the molten steel with the composition described above, pour it to obtain a steel ingot. (2) Preparation of the blank: Roll the steel block into a coil and then cut the coil into plates of suitable size. (3) Deep drawing: Place the plate in a suitable mold and fix it, then press the punch onto the mold with a certain force and repeat the drawing until the housing 1 is formed. (4) Trimming: Cut and trim the excess material during the deep drawing process to ensure that the burrs and flatness of the cut meet the requirements; obtain the housing 1. 2. Preparing the lithium-ion battery

[0088] The positive electrode, the separator and the negative electrode are stacked in this order so that the separator is sandwiched between the positive electrode and the negative electrode to play a separating role, and then wound to obtain a bare cell 2;

[0089] The cell 2 is inserted into the above-prepared casing 1, and the second end wall 12 and the casing 1 are joined by laser welding; after drying, the electrolyte is injected into the bare cell 2, subjected to molding, and volume-fixed to obtain a prepared lithium-ion battery.

[0090] In the above manufacturing process, the positive electrode, separator, negative electrode, and electrolyte may be conventional positive electrodes, separators, negative electrodes, and electrolytes in the prior art; conventional commercially available products may be used, and they may also be manufactured by the conventional manufacturing methods in the prior art. Specific examples further illustrate the present invention: Examples 1-17:

[0091] Examples 1-17 each show a battery as shown in the Fig. 1 and Fig. 2, wherein the shape of the housing 1 is cylindrical.

[0092] The chemical composition of the material of the housing 1 includes: C, Si, Mn, P, S, Ti, Nb, Cr and Fe; wherein, based on the total mass of the steel, the mass fractions 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%;

[0093] The mass fractions of Cr, Ti and Nb are given in Table 1;

[0094] The rest is iron. The procedure for manufacturing the battery is as follows:1. Preparation of the housing (1) Steel preparation: Melt the steel to remove impurities and precisely adjust the chemical composition required for the shell 1. After obtaining the steel with the composition described above, cast it to obtain a steel ingot. (2) Preparation of the blank: Roll the steel ingot into a coil. During the rolling process, adjust the thickness of the coil by adjusting the size, pitch, and speed of the rolling mill rolls to produce a casing 1 with different thicknesses d of the first end wall 11, and then cut the coil into plates of appropriate sizes. (3) Deep drawing: Place the plate in a suitable mold and fix it, then press the punch onto the mold with a certain force and repeat the drawing until the housing 1 is formed. The formed housing 1 is cylindrical with a volume of 10048 mm 3 . (4) Trimming: Cut and trim the excess material during the deep drawing process to ensure that the burrs and flatness of the cut meet the requirements 2. Preparation of the positive electrode

[0095] Mix the active cathodic material LiNi0,9 Co 0,05 Mn 0,05 O3, the conductive agent acetylene black, and the binder PVDF in a mass ratio of 96:2:2, the solvent NMP are added, and the mixture is stirred under the action of a vacuum mixer until uniform, resulting in the positive electrode suspension. The positive electrode suspension is evenly applied to both surfaces of the aluminum foil of the cathodic current collector, dried at room temperature, transferred to an oven for further drying, and then cold-pressed and cut to obtain the positive electrode. 3. Preparation of the negative electrode

[0096] The active anodic material, conductive agent (SP), and binder are mixed in a specific mass ratio (97:1:1), where the active anodic material contains artificial graphite and silicon-carbon material, and the ratio of artificial graphite to silicon-carbon is 92:5. Then, the solvent and deionized water are added, and the mixture is stirred under the action of a vacuum mixer until uniform, to obtain the negative electrode suspension. The negative electrode suspension is evenly coated on both surfaces of the copper foil of the anodic current collector, dried at room temperature, transferred to a furnace for further drying, and then cold-pressed and cut to obtain a negative electrode. 4. Preparation of the electrolyte

[0097] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain an organic solvent, and FEC is added according to the embodiment and comparative example, and then the completely dried lithium salt LiPF6 is dissolved in the mixed organic solvent to prepare an electrolyte with a lithium salt concentration of 1 mol / L. 5. Preparation of the separator

[0098] In the present embodiment, a polyethylene film is selected as the separator, and the polyethylene film is cut to form the separator. 6. Production of the lithium-ion battery

[0099] The above-mentioned positive electrode, separator, and negative electrode are cut into appropriate sizes and stacked in the order of positive electrode-separator-negative electrode so that the separator is sandwiched between the positive electrode and the negative electrode to play a separating role, and then wound to obtain a bare cell 2, the height of the wound cell 2 being a1. The cell 2 is inserted into the housing 1 (manufactured as described above), and the second end wall 12 and the housing 1 are joined by laser welding. After drying, the liquid is injected, subjected to molding, and the volume is fixed to obtain a manufactured lithium-ion battery. X-ray fluorescence spectrometry (1) Sample preparation: First, the stainless steel sample must be properly prepared to allow X-ray penetration and excitation of fluorescence. This may require cutting, grinding, polishing, and other steps to ensure the sample surface is flat and free of contaminants. (2) X-ray excitation: The sample surface is irradiated with high-energy X-rays to excite the characteristic X-ray fluorescence of each element. The wavelength or energy characteristics of these fluorescence spectra correspond to the nature of the elements, allowing the elements contained in the sample to be determined. (3) Spectral detection and analysis: The X-rays reflected from the sample surface and the emitted fluorescence spectra are recorded by a spectrometer. The type and content of the element can be determined based on the position and intensity of the characteristic spectral lines. (4) Matrix effect correction: Due to the interaction between different elements in stainless steel (matrix effect), the collected spectral data must be corrected to eliminate the influence of this interaction on the analysis results and improve the accuracy of the analysis. (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. The procedure for measuring “a” is as follows:

[0100] The height of cell 2 is measured, i.e., the maximum distance a1 from the first end face to the second end face, and the height within housing 1 is measured, i.e., the minimum distance a2 from the first end wall to the second end wall. Three groups of each housing 1 are measured, and the average value is determined. The value of "a" is calculated as a=a2-a1. The measurement of “d” is as follows:

[0101] The thickness of the first end wall 11 is measured using an ultrasonic thickness gauge. During the measurement, three different positions of the first end wall 11 of each housing 1 are measured, and the average value is taken as the thickness "d" of the first end wall 11 of the housing 1. Method for measuring the area of ​​the center hole of the cell winding 21:

[0102] The inner diameter of the center hole of the cell winding 21 is measured three times in different directions, and the average value is taken as the diameter k of the center hole of the cell winding 21. The area S of the center hole of the cell winding 21 is calculated using the following formula: S = π (k / 2) 2 . The values ​​for “a”, “d” and “S” of the manufactured battery are given in Table 1. Examples 18-24:

[0103] Examples 18-24 are similar to Example 1, except that cell 2 includes a positive tab and a negative tab. The positive tab or the negative tab is electrically connected to the case 1, and the positive tab and the negative tab are provided on the same end wall of cell 2. The Cr mass fraction and the values ​​of "a", "b", "c", "d", and "S" of the manufactured battery are given in Table 2. Examples 25-28:

[0104] Examples 25-28 are similar to Example 18, except that the positive tab and the negative tab are provided on the two end walls of cell 2, respectively. The mass fraction of Cr and the values ​​of "a", "b", "c", "d", and "S" of the manufactured battery are given in Table 2. Examples 29-38:

[0105] Examples 29-38 are similar to Example 1, except that, as in Fig. 3, the housing 1 has the shape of a four-sided prism. This version is similar to version 1, with the following differences: 1. The housing is manufactured as follows: (1) Steel preparation: Melt the steel to remove impurities and precisely adjust the chemical composition required for the shell 1. After obtaining the molten steel with the composition described above, pour it to obtain a steel ingot; (2) Preparation of the blank: Roll the steel block into a roll and adjust the thickness of the roll by adjusting the size, gap and speed of the rolling machine during the rolling process to produce a casing 1 with different thickness d of the first end wall 11, and then cut the roll into plates of appropriate size. (3) Deep drawing: Place the plate in a suitable mold and fix it, then press the punch onto the mold with a certain force, exchange the square mold and the punch to transform the circle into a square, and repeat the drawing until the housing 1 is formed. The formed housing 1 is a rectangular cuboid with a volume of 970,000 mm 3 . (4) Trimming: Cut and trim the excess material during the deep drawing process to ensure that the burrs and flatness of the cut meet the requirements. 2. Preparation of the positive electrode

[0106] Mix the active cathodic material LiNi 0,6 Co 0,2 Mn 0,2 O3, the conductive agent acetylene black, and the binder PVDF in a mass ratio of 96:2:2, the solvent NMP are added, and the mixture is stirred under the action of a vacuum mixer until uniform, resulting in the positive electrode suspension. The positive electrode suspension is evenly applied to both surfaces of the aluminum foil of the cathodic current collector, dried at room temperature, transferred to an oven for further drying, and then cold-pressed and cut to obtain the positive electrode. 3. Production of the negative electrode

[0107] Mix the active anodic material (artificial graphite), the conductive agent (SP), and the binder in a specific mass ratio (97:1:1), add the solvent (deionized water), and stir under the action of a vacuum mixer until the mixture is uniform to obtain the negative electrode suspension. The negative electrode suspension is evenly coated on both surfaces of the copper foil of the anodic current collector, dried at room temperature, transferred to a furnace for further drying, and then cold-pressed and cut to obtain the negative electrode.

[0108] The values ​​of “a”, “b”, “c”, “d” and “S” of the manufactured battery are given in Table 3. Comparison examples 1-3

[0109] Comparative Examples 1-3 are similar to Example 1, except that the values ​​of “a”, “b”, “c”, “d” and “S” of the manufactured battery are given in Table 1. Performance test: 1. Deformation degree of the housing 1 after the cycle test:

[0110] The lithium-ion batteries prepared in the examples and comparative examples are cycled at 25 °C according to the following procedure. When the active cathodic material is a nickel-cobalt-manganese ternary, the cycling strategy is as follows: (1) Charge to 4.35 V at a constant current rate of 1C and charge at constant voltage until the current drops to 0.05C; (2) Let stand for 10 minutes; (3) Discharge to 2.75 V at a rate of 1C; (4) Let stand for 10 minutes.

[0111] According to steps (1) to (4), 50 test cycles were carried out to observe the height of the projection at maximum deformation of the first end wall 11, where: No deformation means: The deformation height is between 0 and 0.1 mm; Slight deformation means: The deformation height is between 0.1 and 0.5 mm; Moderate deformation means: The deformation height is between 0.5 and 1 mm; Severe deformation means: more than 1 mm. 2. Procedure for testing the battery capacity:

[0112] Place the battery in a container with a constant temperature of 25 °C and perform the following operations on the test object: (1) Charge with a constant current from 0.33 C to 4.35 V, and charge with a constant voltage until the current drops to 0.05 C; (2) Let stand for 30 minutes; (3) Discharge at 0.33C to a lower limit voltage of 2.75V;Repeat the above steps three times and take the discharge capacity of the third cycle as the capacity of the battery. 3. Housing forming rate

[0113] According to the manufacturing method of the above-mentioned housing 1, the housing 1 is deep-drawn and formed, and the forming rates of 200 housings 1 are statistically prepared.

[0114] The comparative analysis of Examples 1-12, 29-38 and Comparative Examples 1-3 shows that the housing 1 has a higher forming rate when 0.15≤a[d×(b+c)]≤300 300 is met. At the same time, after 50 battery charge and discharge cycle tests, the degree of deformation of the casing 1 caused by the expansion of the cell 2 is small, and the energy density of the battery is not too low. Based on this, the deformation rate of the casing 1 is higher if it is also satisfactory.

[0115] If the housing 1 is cylindrical, if equation 1 ≤ a / [d × (b + c)] ≤ 200 is satisfied, 0.15 < d< 1.2mm, 0.5 <a< 10mm, 0,25<b+c<0,5 Gew.-% ebenfalls erfüllt, und die Formungsrate des Gehäuses 1 ist hoch und es tritt keine Verformung auf. Wenn das Gehäuse 1 die Form eines viereckigen Prismas hat, sind 0,15<d<1,2 mm, 0,1<a<8 mm, 0,25<b+c<0,5 Gew.-% ebenfalls erfüllt, und die Formungsrate des Gehäuses 1 ist hoch, und es tritt keine Verformung auf. Da sich das zylindrische Gehäuse 1 am ehesten aufgrund der Ausdehnung der Zelle 2 an der Endwand verformt, während sich das viereckig-prismatische Gehäuse 1 der Batterie am ehesten aufgrund der Ausdehnung der Zelle 2 an der Seitenwand 13 mit der größten Fläche verformt. Damit das Gehäuse 1 eine hohe Formungsrate und keine Verformung aufweist, beträgt das „a“ des zylindrischen Gehäuses 1 0,5<a< 10mm, während das „a“ des viereckigen Prismas 0,1 <a<8mm beträgt.

[0116] At the same time, if the housing 1 has the shape of a quadrangular prism with an aspect ratio of more than 2, that is, the degree of deformation of the side wall 13 during the deep drawing process is large, the better the plastic formability required for deep drawing, but the risk of deformation of the housing 1 due to the expansion of the cell 2 is higher. When b+c is 0.2 to 0.7 wt%, the degree of deformation of the housing 1 is lower, taking into account the forming rate of the housing 1.

[0117] As can be seen from Examples 13 to 17, the center hole of the cell coil 21 can be used as a gas storage space to reduce the expansion rate of the cell 2, so that when the condition is met, the possibility of deformation of the case 1 is reduced. When the area of ​​the center hole of the cell coil 21 is less than 0.4, the center hole of the cell coil 21 cannot store gas due to the small area of ​​the center hole of the cell coil, and the case 1 is prone to deformation.

[0118] As can be seen from Examples 18 to 28, the excessive Cr content reduces the forming rate of the housing 1. When the positive tab and the negative tab are provided at the same end of the cell 2, the heat is concentrated, resulting in an increased risk of deformation of the end wall of the housing 1. In order to keep the forming rate of the housing 1 high and avoid deformation, a 0.5 <a< 10 mm erfüllen, wenn die positive Lasche und die negative Lasche an derselben Seite der Zelle 2 vorgesehen sind, und a 0,1 <a<8 mm erfüllen, wenn die positive Lasche und die negative Lasche an beiden Seiten der Zelle 2 vorgesehen sind.

[0119] Finally, it should be noted that the above embodiments serve only to illustrate the technical solution of this article and not to limit the scope of this article. Although this application is described in detail with reference to the preferred embodiments, one skilled in the art should understand that the technical solution of this article may be modified or replaced with equivalents without departing from the spirit and scope of the technical solution of this article.

Claims

[1] Battery comprising a housing (1) and a cell (2) provided in the housing (1), wherein the material of the housing (1) comprises steel, characterized by in that the composition of the steel comprises Ti, Nb and Cr, wherein, based on the total mass of the steel, the mass fraction of Cr is ≥ 16 wt.%; the housing (1) comprises a side wall (13) and an end wall, the end wall has a first end wall (11) and a second end wall (12), which are each arranged at both ends of the side wall (13), and the two ends of the cell (2) have a first end surface near the first end wall (11) and a second end surface near the second end wall (12); wherein the first end wall (11) and the side wall (13) are integrally formed; wherein the housing (1) satisfies the following relationship: 0.15 ≤ a / [d × (b + c)] ≤ 300; where “a” is the sum of the distance of the first end face to the first end wall (11) and the distance of the second end face to the second end wall (12) in mm; “d” is the thickness of the first end wall (11) in mm; “b” is the mass fraction of Ti relative to the total mass of the steel, in wt%; “c” is the mass fraction of Nb, based on the total mass of the steel, in wt.%. [2] Battery according to claim 1, characterized by that the housing (1) satisfies the following relationship: 1≤a / [d×(b+c)]≤200. [3] Battery according to claim 1 or 2, characterized by that the range of “b+c” is 0.2 to 0.8 wt%. [4] Battery according to claim 3, characterized by that the range of “b+c” is 0.25 to 0.5 wt%. [5] Battery according to claim 4, characterized by that the range of “b” is 0.05 to 0.2 wt%. [6] Battery according to claim 1, characterized by that the range of “c” is 0.17 to 0.5 wt%. [7] Battery according to claim 1 or 2, characterized by that the range of “d” is 0.15 to 1.2 mm. [8] Battery according to claim 1 or 2, characterized by that the range of “a” is 0.1 to 10 mm. [9] Battery according to claim 1 or 2, characterized by that the battery is a cylindrical battery. [10] Battery according to claim 9, characterized by that the range of “a” is 0.5 to 10 mm. [11] Battery according to claim 9, characterized by that the cell is provided with a central hole of the cell winding and the battery satisfies the following relationship: 0.4 ≤ S × a ≤ 600; where “S” is the area of ​​the central hole of the cell winding (21) in mm 2 is. [12] Battery according to claim 1 or 2, characterized by that the battery is a square-prismatic battery. [13] Battery according to claim 12, characterized by that the range of “a” is 0.1 to 8 mm. [14] Battery according to claim 12, characterized by that when the aspect ratio of the housing (1) is not less than 2, the range of "b+c" is 0.2 to 0.7 wt%. [15] Battery according to claim 1, characterized by that the cell (2) comprises a positive tab and a negative tab, wherein the positive tab or the negative tab is electrically connected to the housing (1) and the mass fraction of Cr is 16 to 30 wt.%. [16] Battery according to claim 15, characterized by that the positive tab and the negative tab are both provided on the first end face or the second end face of the cell (2) and the range of "a" is 0.5 to 10 mm. [17] Battery according to claim 16, characterized by that the positive tab and the negative tab are provided on the first end face and the second end face of the cell (2) respectively and the range of "a" is 0.2 to 8 mm. [18] Battery pack, characterized by a battery according to any one of claims 1 to 17.

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