A shell, a battery monomer and an electric device

Abstract

The present application relates to the technical field of new energy, and discloses a shell, a battery monomer and an electric device, the shell is suitable for accommodating the battery core, the shell comprises an end wall, the maximum wall thickness difference of the end wall is A mm, and the following condition is met: A mm <= 0.25 mm; the end wall comprises a first surface and a second surface, and a score groove is arranged on the end wall, the score groove comprises a groove bottom wall and a groove side wall, the groove side wall is arranged obliquely relative to the groove bottom wall, the included angle between the groove bottom wall and the groove side wall is alpha degree, the minimum distance between the groove bottom wall and the second surface is h mm, and the following conditions are met: 3.5 * 10 ‑4 <= h / alpha <= 1.05 * 10 ‑3 . By limiting the maximum wall thickness difference A of the end wall and the range of h / alpha, the structural strength of different regions of the score groove is ensured to be consistent, the blasting pressure deviation of different parts of the score groove is reduced, and the situation that part of the region cannot crack normally and the residual stress cannot be effectively released due to uneven local thickness distribution of the score groove is avoided.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, specifically to a casing, a battery cell, and an electrical device. Background Technology

[0002] During the battery manufacturing process, the structure and processing precision of the battery casing directly affect the safety performance of the battery. In particular, the processing quality of the casing has a significant impact on the opening performance of the explosion-proof valve.

[0003] During the manufacturing process of existing battery casings, the maximum wall thickness difference and inconsistent thickness distribution of the end walls with grooves on the casing result in significant deviations in the battery's burst pressure, which in turn affects the normal realization of the battery's burst function. Summary of the Invention

[0004] This invention provides a casing, a battery cell, and an electrical device to solve the problem in related technologies where the maximum wall thickness difference of the end walls with grooves on the battery casing is inconsistent, resulting in a large deviation in the burst pressure of the battery.

[0005] In a first aspect, the present invention provides a housing suitable for accommodating a battery cell, the housing including end walls, the maximum wall thickness difference of the end walls being A mm, satisfying: A mm ≤ 0.25 mm; The end wall includes a first surface and a second surface, which are arranged opposite to each other. A groove is formed on the first surface of the end wall, recessed towards the second surface. The groove includes a bottom wall and a side wall, with the bottom wall inclined relative to the side wall. The included angle between the bottom wall and the side wall is α°. The minimum distance between the bottom wall and the second surface is h mm, satisfying 3.5 × 10⁻⁶ mm. -4 ≤h / α≤1.05×10 -3 .

[0006] Beneficial effects: By limiting the maximum wall thickness difference A of the end walls, the structural strength of different areas of the groove is ensured to be consistent, making the burst pressure of different parts of the groove more consistent. This mitigates the problem of residual stress in some areas being difficult to release due to uneven local thickness distribution of the groove, which could prevent the groove from cracking normally. Based on limiting the maximum wall thickness difference A, the range of the ratio h to α is further limited to reduce the deviation of the casing's burst pressure. When the formula value of h / α is too small, the structural strength at the groove is weak, and the explosion-proof valve may prematurely and abnormally open before reaching the design burst pressure, damaging the battery's sealing structure. When the formula value of h / α is too large, the structural strength at the groove is strong, and the burst pressure required for the explosion-proof valve to open is large. After abnormal gas generation and pressure rise inside the battery, the explosion-proof valve may not be able to open in time to release pressure, and the pressure inside the casing may continue to accumulate, easily causing the casing to crack. The overflow of high-temperature and high-pressure contents can induce a chain reaction of thermal runaway in surrounding batteries. When the end wall is shaped so that the maximum wall thickness difference A and h / α are within the above range, the wall thickness of the end wall is relatively uniform. Since the residual stress formed by the machining of the groove is effectively released, the burst pressure of different parts of the groove is the same, and the groove can crack and release pressure smoothly under the rated burst pressure.

[0007] Secondly, the present invention also provides a battery cell, including a battery cell and a housing as described above, wherein the battery cell is disposed within the housing.

[0008] Since the battery includes a casing and has the same effect as the casing, it will not be elaborated further here.

[0009] Thirdly, the present invention also provides an electrical device, including an electrical device body and a battery as described above that is electrically connected to the electrical device body.

[0010] Since electrical equipment includes individual battery cells and has the same effect as individual battery cells, it will not be elaborated on here. Attached Figure Description

[0011] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the structure of a shell according to an embodiment of the present invention; Figure 2 for Figure 1 The front view of the casing is shown; Figure 3 for Figure 2 Schematic diagram of section AA; Figure 4 for Figure 3 A magnified view of part A in the image; Figure 5 for Figure 4 A magnified view of part B in the image; Figure 6 for Figure 4 A magnified view of part B in the image; Figure 7 This is an exploded view of a battery pack according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the structure of an electrical device according to an embodiment of the present invention.

[0013] Explanation of reference numerals in the attached figures: 1. End wall; 11. First surface; 12. Second surface; 13. Score groove; 131. Groove opening; 132. Groove bottom wall; 133. Groove side wall; 14. Reinforcing rib; 141. Recess; 15. Groove; 16. First protrusion; 2. Side wall; 3. Injection hole; 300. Battery pack; 310. Housing; 320. Cover plate; 330. Battery assembly; 400. Vehicle; 410. Controller; 500. Battery device. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] During the battery manufacturing process, the structure and processing precision of the battery casing directly affect the safety performance of the battery. In particular, the processing quality of the casing has a significant impact on the opening performance of the explosion-proof valve.

[0016] Battery explosion-proof valves come in various structural forms, including integrated and split types. Integrated explosion-proof valves have grooves machined directly into the bottom wall of the casing, creating a weak point. This weak point is typically formed by stamping, resulting in a raised structure on the reverse side of the stamped valve. This leads to a significant difference in the maximum wall thickness at the battery's bottom surface, necessitating an additional shaping process. However, uneven material feeding during shaping can easily occur, preventing the maximum wall thickness difference at the battery's bottom surface from meeting the ideal requirements. Uneven thickness distribution and ineffective release of residual stress result in a large deviation in the battery's burst pressure, ultimately affecting the normal operation of the battery's explosion function.

[0017] The following is combined Figures 1 to 8Embodiments of the present invention are described.

[0018] According to an embodiment of the present invention, in one aspect, a housing is provided, the housing being adapted to accommodate a battery cell, the housing including an end wall 1, the maximum wall thickness difference of the end wall 1 being A mm, satisfying: A mm ≤ 0.25 mm; The end wall 1 includes a first surface 11 and a second surface 12, which are arranged opposite to each other. A groove 13 recessed towards the second surface 12 is formed on the first surface 11 of the end wall 1. The groove 13 includes a bottom wall 132 and two side walls 133. The two side walls 133 are respectively inclined relative to the bottom wall 132. The included angle between the bottom wall 132 and either side wall 133 towards the groove 13 is α°. The minimum distance between the bottom wall 132 and the second surface 12 is h mm, satisfying 3.5 × 10⁻⁶ mm. -4 ≤h / α≤1.05×10 -3 .

[0019] A housing is a component used to provide a space to house electrode assemblies and other parts and isolate them from the outside environment. A housing generally includes a body with an opening at at least one end and a receiving cavity. The opening of the housing can be closed by a cover plate to seal and isolate the internal environment of the battery cell from the external environment.

[0020] The materials of the casing include, but are not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, and aluminum-plastic film.

[0021] It should be noted that after the groove 13 is processed by stamping in the direction of the first surface 11 toward the second surface 12, a raised structure will be formed on the second surface 12. Therefore, an additional shaping process is required to shape the raised structure and smooth the second surface 12. However, due to the uneven material feeding problem in the shaping process, the thickness of the end wall 1 will be different in various places. The maximum wall thickness difference A refers to the difference between the actual average wall thickness of the end wall 1 and the designed wall thickness, which is used to assess the degree of deviation from the design value.

[0022] For example, the value of the maximum wall thickness difference A can be measured and read by a coordinate measuring machine, and the end wall 1 can be pressed by a shaping fixture to adjust the maximum wall thickness difference A of the end wall 1.

[0023] It's important to note that a battery cell is the component within a battery where electrochemical reactions occur; it's the smallest unit in a battery capable of performing electrochemical reactions such as charging and discharging. A battery cell typically consists of a positive electrode, a negative electrode, and a separator. Taking a lithium-ion battery cell as an example, it primarily functions by the intercalation and deintercalation of lithium ions between the positive and negative electrodes.

[0024] During battery charging, active ions (such as Li) from the positive electrode are embedded in the negative electrode, while electrons from the positive electrode are transferred to the negative electrode through an external circuit to maintain charge balance. During discharge, active ions (such as lithium ions) previously embedded in the negative electrode can be released, while electrons from the negative electrode are transferred to the positive electrode through an external circuit to maintain charge balance, thus achieving energy storage and release.

[0025] Reference Figure 4 In this embodiment, a groove 13 is formed on the end wall 1 of the housing by stamping. The area enclosed by the groove 13 can serve as an explosion-proof valve for the housing, specifically an integrated explosion-proof valve. Since the end wall 1 at the groove 13 is thinner, when a large amount of gas is generated inside the cell due to abnormal conditions such as overcharging, short circuit, or high temperature, the explosion-proof valve will preferentially open along the groove 13 to quickly release the pressure inside the housing, preventing the housing from bulging severely, or even causing the battery to catch fire or explode, resulting in equipment damage and safety accidents.

[0026] It should be noted that the end wall 1 in this embodiment does not specifically refer to the sealing plate structure at both ends of the shell; it can be any flat wall surface on the shell. As long as the wall surface is continuous and complete, and can meet the stamping requirements of the groove 13, it can be used as the end wall 1 of this solution and an integrated explosion-proof valve can be installed. After the groove 13 is opened along the preset trajectory, the enclosed area formed by it is the integrated explosion-proof valve. Since the wall thickness of the groove 13 is less than that of other areas of the end wall 1, the groove 13 is the weak pressure relief part of the entire shell. When the internal pressure of the shell reaches the opening threshold of the explosion-proof valve, the explosion-proof valve tears along the trajectory of the groove 13. In actual production and assembly, the processing surface can be selected according to the overall shape of the battery, the internal cell arrangement, the installation space of the whole machine, and the requirements of the pressure relief direction, adapting to various battery products with different structures, thus broadening the scope of application.

[0027] When the groove 13 is formed by stamping, the stamping force will cause local bulging deformation at the corresponding position of the end wall 1 of the shell. However, during the forming process, the sheet metal is prone to uneven feeding, resulting in uneven wall thickness of the end wall 1. At the same time, the internal residual stress caused by stamping and forming cannot be fully released and remains in the area around the explosion-proof valve groove. When the battery cell is subjected to temperature changes and charging and discharging expansion stress in subsequent use, the residual internal stress will change the original preset fracture strength of the groove 13, causing the explosion-proof valve to open abnormally prematurely before reaching the set opening pressure, resulting in abnormal malfunctions such as battery leakage and failure.

[0028] The groove 13 includes a bottom wall 132 and a side wall 133. The bottom wall 132 refers to the wall surface perpendicular to the recessed direction of the groove 13. In this embodiment, the extension direction of the bottom wall 132 is parallel to the plane where the second surface 12 is located. The side wall 133 refers to the transition inclined wall surface connecting the first surface 11 and the bottom wall 132. h is the minimum distance between the bottom wall 132 and the plane where the second surface 12 is located.

[0029] By limiting the maximum wall thickness difference A of end wall 1, the wall thickness of end wall 1 is made more uniform, reducing the thickness difference at various points on end wall 1. This makes the structural strength of different areas of the groove 13 more consistent, reducing the explosion pressure deviation of different parts of the groove. It also prevents the residual stress in some areas from being difficult to release effectively due to uneven local thickness distribution of the groove 13, which could lead to the groove failing to crack normally. Based on limiting the maximum wall thickness difference A of end wall 1, the range of the ratio of h to α is further limited to reduce the explosion pressure deviation of the shell. When the formula value of h / α is too small, the structural strength at the groove 13 is weak, and the explosion-proof valve will prematurely and abnormally burst open before reaching the design explosion pressure, damaging the battery sealing structure. When the formula value of h / α is too large, the structural strength at the groove 13 is strong, and the explosion pressure required to open the explosion-proof valve is large. After abnormal gas generation and pressure rise inside the battery, the explosion-proof valve cannot open in time to release pressure. The pressure inside the shell continues to accumulate, which can easily cause the shell to crack. After the high-temperature and high-pressure contents overflow, it can induce a chain thermal runaway of surrounding batteries. When the end wall is shaped so that the maximum wall thickness difference A and h / α are within the above range, the wall thickness of end wall 1 is relatively uniform. As the residual stress formed by the machining groove is effectively released, the burst pressure of different parts of the groove tends to be the same, and the groove can crack and release pressure smoothly under the rated burst pressure.

[0030] For example, in this embodiment, the value of A can be 0.04 mm or 0.09 mm or 0.13 mm or 0.16 mm or 0.18 mm or 0.20 mm or 0.21 mm or 0.22 mm or 0.23 mm or 0.25 mm, or it can be any range formed by any two of the above values.

[0031] For example, in this embodiment, the value of h / α can be 3.7 × 10⁻⁶. -4 Or 4.2×10 -4 Or 4.9×10 -4 Or 5.6×10 -4 Or 1.01×10 -3 Or 1.04×10 -3 "etc." can also be the range formed by any two of the above values.

[0032] In one embodiment, the minimum distance h mm between the bottom wall 132 of the groove and the second surface 12 satisfies 0.05 mm ≤ h mm ≤ 0.1 mm.

[0033] Reference Figure 4 and Figure 6 The distance between the bottom wall 132 of the groove and the second surface 12 is the remaining wall thickness of the end wall 1 at the location of the groove 13. For example, the bottom wall 132 of the groove is a planar structure parallel to the second surface 12, or the bottom wall 132 of the groove is set as an arc-shaped structure.

[0034] If the value of h is too small, the remaining wall thickness of the end wall 1 at the groove 13 will be too thin, resulting in insufficient local structural strength of the explosion-proof valve. This can easily lead to premature valve opening before the rated working pressure is reached, thus damaging the sealing integrity of the shell. If the value of h is too large, the remaining wall thickness of the end wall 1 at the groove 13 will be too thick, which will increase the explosion threshold of the explosion-proof valve. This will cause the explosion-proof valve to fail to rupture and release pressure normally after the gas is generated and pressurized inside the battery, leading to the risk of high-temperature medium leakage and thermal runaway of surrounding cells.

[0035] For example, in this embodiment, the value of h mm can be 0.053 mm, 0.061 mm, 0.067 mm, 0.072 mm, 0.079 mm, or 0.083 mm, or it can be any range formed by any two of the above values.

[0036] In one embodiment, the second surface 12 is located on the side of the end wall 1 facing the interior of the housing.

[0037] By placing the second surface 12 on the side of the end wall 1 facing the inside of the housing, the scoring groove 13 formed on the first surface 11 is located outside the end wall 1, preventing the electrolyte inside the housing from directly contacting the inner wall of the scoring groove 13. This effectively blocks the electrolyte from wetting and corroding the bottom wall 132 and side wall 133 of the scoring groove 13, preventing abnormal thinning of the wall thickness of the scoring groove 13 after being corroded by the electrolyte. This avoids the hidden danger of the explosion-proof valve opening prematurely due to corrosion, maintains the original structural dimensions and preset burst pressure of the scoring groove for a long time, and ensures the long-term stable and reliable valve opening performance of the explosion-proof valve.

[0038] As an alternative implementation, the second surface 12 is located on the side of the end wall 1 facing the outside of the housing. At this time, the groove 13 is located on the inner side of the end wall 1 facing the inside of the housing and will be in direct contact with the electrolyte inside the housing. Therefore, the end wall 1 can be made of corrosion-resistant alloys such as titanium alloy, or an anti-corrosion coating can be applied to the side wall 133 and bottom wall 132 of the groove 13 on the first surface 11. This can form a dense protective film on the side wall 133 and bottom wall 132 of the groove 13, which can isolate the electrolyte from contact with the base material of the end wall 1, effectively block the penetration of corrosive media, avoid abnormal erosion and thinning of the groove 13 wall thickness, prevent the explosion-proof valve from opening prematurely or the explosion pressure from shifting due to corrosion, and ensure the long-term stable operation of the explosion-proof structure.

[0039] In one embodiment, in the extension direction parallel to the first surface 11 and perpendicular to the groove 13, the width of the projection of the groove bottom wall 132 onto the first surface 11 is B mm, satisfying 0.13 mm ≤ B mm ≤ 0.35 mm.

[0040] Reference Figure 6 The width B mm of the bottom wall 132 is specifically the distance between the connecting edge of the groove sidewall 133 and the bottom wall 132 of the groove 13 on the side of the groove 13 near the injection hole 3 and the connecting edge of the groove sidewall 133 and the bottom wall 132 of the groove 13 on the side of the groove 13 away from the injection hole 3, in the direction parallel to the first surface 11 and perpendicular to the extension direction of the groove 13.

[0041] When the value of B is too small, the width of the bottom wall 132 of the groove is too narrow, the weak area of ​​the groove 13 is insufficient, the overall tear resistance of the groove position is too high, the explosion pressure of the explosion-proof valve increases accordingly, and it is difficult to crack and release pressure normally when the internal pressure of the battery exceeds the standard, which can easily lead to problems such as high pressure medium in the shell and induction of heat runaway. When the value of B is too large, the bottom wall 132 of the groove is too wide, which will increase the stress area of ​​the weak area of ​​the groove and reduce the structural strength. The explosion-proof valve is very likely to open abnormally and prematurely before the set pressure is reached.

[0042] For example, in this embodiment, the value of B mm can be 0.136 mm or 0.152 mm or 0.171 mm or 0.195 mm or 0.208 mm or 0.223 mm or 0.247 mm or 0.261 mm or 0.279 mm, or it can be any range formed by any two of the above values.

[0043] In one embodiment, the groove 13 includes a notch 131, which is located at one end of the groove 13 away from the bottom wall 132. The width of the notch 131 is defined as C mm in the extension direction parallel to the first surface 11 and perpendicular to the groove 13, satisfying 0.25≤CB≤0.57.

[0044] If the CB value is too small, the difference between the width of the groove 131 and the width of the bottom wall 132 of the groove 13 will be small, resulting in a narrow discharge channel formed after the explosion-proof valve cracks, making it difficult for the high-temperature electrolyte and gas generated by the battery thermal runaway to be quickly ejected and depressurized. If the CB value is too large, the excessive widening of the groove 131 relative to the width of the bottom wall 132 will excessively weaken the strength of the peripheral end wall 1 of the groove 13, causing the explosion-proof valve to prematurely and abnormally burst open.

[0045] For example, in this embodiment, the value of CB can be 0.262mm or 0.287mm or 0.305mm or 0.331mm or 0.359mm or 0.384mm or 0.402mm or 0.426mm or 0.453mm or 0.481mm or 0.515mm, or it can be any range formed by any two of the above values.

[0046] In one embodiment, the end wall 1 is provided with a reinforcing rib 14, which protrudes into the housing relative to the second surface 12, and the reinforcing rib 14 is provided with a recess 141 on the side opposite to the second surface 12.

[0047] For example, in the cross section perpendicular to the extension direction of the reinforcing rib 14, the protrusion shape of the reinforcing rib 14 is trapezoidal, arc-shaped, or rectangular. The reinforcing rib 14 extends continuously along the groove 13, or it can be arranged in segments at intervals; the reinforcing rib 14 and the end wall 1 are manufactured by an integral stamping process.

[0048] As an extended implementation, the reinforcing rib 14 protrudes outward from the shell relative to the first surface 11, and is also manufactured using an integral stamping process, which simplifies the forming method. A rounded corner is provided at the root position where the reinforcing rib 14 connects to the end wall 1 to eliminate sharp edges at the joint and alleviate stress concentration problems caused by abrupt structural changes.

[0049] A reinforcing rib 14 is provided on the second surface 12 of the end wall 1 facing the inner side of the housing. This can improve the structural strength of the end wall 1 around the groove 13. When the internal pressure of the battery triggers the explosion-proof valve to burst, the bursting force is concentrated on the weak area of ​​the groove 13, causing the explosion-proof valve to burst open along the preset groove position. At the same time, due to the presence of the reinforcing rib 14, the end wall 1 around the groove 13 is less prone to deformation.

[0050] In one embodiment, the housing further includes a sidewall 2, which is adapted to enclose the end wall 1 to form an accommodating space. The scoring groove 13 is disposed on the side of the reinforcing rib 14 away from the sidewall 2. In the extension direction parallel to the first surface 11 and perpendicular to the scoring groove 13, the minimum distance between the reinforcing rib 14 and the scoring groove 13 is K mm, which satisfies that 2 mm ≤ K mm ≤ 7 mm.

[0051] For example, the side wall 2 and the end wall 1 can be manufactured by an integral stamping process without additional assembly; as an alternative implementation, the side wall 2 and the end wall 1 can also be assembled by welding or by using threaded connection, riveting and sealing to adapt to different processing technology and usage scenarios.

[0052] If the value of K is too large, the reinforcing rib 14 will be too far from the groove 13, and will not be able to effectively restrain the deformation of the surrounding end wall 1. When the internal pressure of the battery casing increases, the end wall 1 will easily bulge first to disperse the pressure, resulting in the explosion-proof valve opening pressure being too high and difficult to release pressure normally. If the value of K is too small, the distance between the reinforcing rib 14 and the groove 13 will be too close, which will easily cause local stress concentration. During normal use of the battery, the groove 13 may burst open abnormally, which poses a certain safety hazard.

[0053] For example, in this embodiment, the value of K mm can be 2.1 mm or 2.5 mm or 3.2 mm or 3.6 mm or 4.0 mm or 4.4 mm or 4.9 mm, or it can be a range formed by any two of the above values.

[0054] In one embodiment, the width of the reinforcing rib 14 is D mm in the direction parallel to the first surface 11 and perpendicular to the extension direction of the reinforcing rib 14, satisfying that 1 mm ≤ D mm ≤ 5 mm.

[0055] If the value of D is too small, the reinforcing rib 14 will not be able to effectively enhance the shell strength near the groove 13. Under the action of internal pressure, the shell around the groove 13 will easily deform in advance to disperse the stress, making it difficult for the pressure to concentrate at the weak position of the groove 13, causing the explosion-proof valve to be difficult to open and the opening pressure to exceed the standard. If the value of D is too large, the reinforcing rib 14 will occupy too much space on the end wall 1, squeezing the layout position of other structures such as the groove 15 and the injection hole 3, which is not conducive to the arrangement of various components on the end wall 1.

[0056] It should be noted that the width of the reinforcing rib 14 can be uniform or unequal, as long as the width of the reinforcing rib 14 is within the above-mentioned range in the direction parallel to the first surface 11 and perpendicular to the extension direction of the reinforcing rib 14.

[0057] For example, in this embodiment, the value of D mm can be 1.1 mm or 1.4 mm or 1.9 mm or 2.3 mm or 2.8 mm or 3.2 mm or 3.6 mm, or it can be a range formed by any two of the above values.

[0058] In one embodiment, the housing further includes a sidewall 2, and an endwall 1 forms a first protrusion 16 on the side facing the interior of the housing. The first protrusion 16 is provided with a groove 15 on the side facing away from the interior of the housing. In the extension direction parallel to the first surface 11 and perpendicular to the groove 13, the minimum distance between the groove 15 and the groove 13 is E mm, which satisfies 5 mm ≤ E mm ≤ 9 mm.

[0059] By setting the first protrusion 16, the end wall 1 becomes an uneven plate-like structure. Compared to a flat plate-like structure, the uneven structure can improve the structural rigidity of the end wall 1, making it less prone to deformation under the load of the battery cell and the internal gas load caused by abnormal gas production in the cell. This reduces the deformation of the end wall 1, which would cause the groove 13 to deform and affect the burst pressure of the explosion-proof valve. It should be noted that when E and K are selected, the minimum distance E between the groove 15 and the groove 13 is greater than the minimum distance K between the groove 13 and the reinforcing rib 14. The main function of the reinforcing rib 14 is to ensure that the force is concentrated at the groove 13 when the explosion-proof valve bursts, so that the explosion-proof valve can open along the preset trajectory. The main function of the first protrusion 16 is to improve the structural strength of the end wall 1 and prevent the end wall 1 from bulging and deforming.

[0060] For example, in a cross-section perpendicular to the extension direction of the groove 15, the groove 15 can be rectangular, arc-shaped, or trapezoidal. The bottom of the groove 15 is a plane or an arc surface, and the groove sidewall 133 and the end wall 1 have a vertical or inclined transition. The groove 15 is directly formed by an integral stamping process and is an integral structure with the end wall 1. To reduce stress concentration, a rounded corner transition structure is provided at the connection between the groove 15 and the end wall 1.

[0061] As an extended implementation, the first protrusion 16 is formed to protrude outward toward the outside of the housing.

[0062] For example, in this embodiment, the value of E mm can be 5.2 mm or 5.7 mm or 6.1 mm or 6.6 mm or 7.0 mm or 7.4 mm or 7.8 mm, or it can be a range formed by any two of the above values.

[0063] In one embodiment, the distance between the side of the first protrusion 16 facing the inside of the housing and the second surface 12 is F1mm; The end wall 1 is provided with a reinforcing rib 14, which protrudes into the housing relative to the second surface 12. The distance between the bottom wall of the reinforcing rib 14 away from the first surface 11 and the second surface 12 is F2 mm, which satisfies that F1 mm > F2 mm.

[0064] In this embodiment, the housing includes a support plate disposed between the battery cell and end wall 1 to support the battery cell. The support plate is made of insulating material to isolate the charged battery cell from the metal housing and prevent the battery cell from contacting the housing and causing a short circuit.

[0065] The limitation F1 mm > F2 mm means that the height of the first protrusion 16 protruding into the housing is greater than the height of the reinforcing rib 14. In addition to strengthening the structural strength of the end wall 1, the first protrusion 16 can also support the support plate, so that the load of the support plate is only borne by the first protrusion 16, and the load of the battery cell will not act on the area around the reinforcing rib 14 and the groove 13.

[0066] F1 mm satisfies 0.2 mm ≤ F1 mm ≤ 0.8 mm, and F2 mm satisfies 0.2 mm ≤ F2 mm ≤ 0.7 mm. For example, in this embodiment, the value of F1 mm can be 0.21 mm, 0.26 mm, 0.33 mm, 0.40 mm, 0.45 mm, 0.52 mm, 0.58 mm, 0.61 mm, 0.66 mm, 0.70 mm, 0.73 mm, 0.76 mm, or 0.79 mm, and the value of F2 mm can be 0.22 mm, 0.27 mm, 0.34 mm, 0.39 mm, 0.43 mm, 0.48 mm, 0.51 mm, 0.55 mm, 0.59 mm, 0.62 mm, 0.65 mm, or 0.68 mm, or it can be any range formed by any two of the above values. It should be noted that when taking the value, F1 mm must satisfy F2 mm.

[0067] In one embodiment, the width of the first protrusion 16 is 1 mm in the extension direction parallel to the first surface 11 and perpendicular to the groove 15, satisfying 3 mm ≤ 1 mm ≤ 10 mm.

[0068] It should be noted that, since the first protrusion 16 is used to strengthen the overall deformation resistance of the end wall 1, while the reinforcing rib 14 is only used to strengthen the strength of the end wall 1 around the groove 13 to ensure that the explosion-proof valve can open smoothly, the width of the first protrusion 16 is greater than the width of the reinforcing rib 14.

[0069] If the width I of the first protrusion 16 is too small, the end wall 1 is prone to bulging and deformation under internal pressure. The deformation of the end wall 1 will pull the area of ​​the groove 13, change the original stress distribution at the groove 13, and cause the original burst pressure of the explosion-proof valve to deviate from the design threshold. If the value of I is too large, the first protrusion 16 occupies too much area on the end wall 1, squeezing the remaining effective layout space of the end wall 1, which is not conducive to the layout of other structures such as the injection hole 3 and the reinforcing rib 14 on the end wall 1.

[0070] It should be noted that the width of the first protrusion 16 can be uniform or unequal, as long as the width of the first protrusion 16 is within the above-mentioned range in the direction parallel to the first surface 11 and perpendicular to the extension direction of the first protrusion 16.

[0071] For example, in this embodiment, the value of 1 mm can be 3.1 mm or 3.7 mm or 4.5 mm or 5.2 mm or 6.0 mm or 6.8 mm or 7.3 mm or 7.9 mm or 8.4 mm or 8.8 mm or 9.2 mm, or it can be a range formed by any two of the above values.

[0072] In one embodiment, an injection hole 3 is provided on the end wall 1. In the extension direction parallel to the first surface 11 and perpendicular to the scoring groove 13, the minimum distance between the injection hole 3 and the scoring groove 13 is G mm, which satisfies 24 mm ≤ G mm ≤ 29 mm.

[0073] Reference Figure 3 The minimum distance G between the injection hole 3 and the scoring groove 13 is specifically the distance between the connection edge of the scoring groove 131 and the first surface 11 and the hole wall of the injection hole 3.

[0074] It should be noted that the injection hole 3 is used to inject electrolyte into the casing. The electrolyte is the conductive medium for the migration of active ions in the battery cell and is a key raw material to ensure the electrochemical performance of the battery.

[0075] If the value of G is too large, the injection hole 3 will be biased towards the electrode arrangement area at the edge of the end wall 1, and the electrode tab will block the flow path of the electrolyte. This will not only reduce the electrolyte injection efficiency, but also easily cause local lack of electrolyte inside the cell. If the value of G is too small, the deformation and residual stress of the end wall 1 generated by the processing of the injection hole 3 will affect the scoring groove 13, which will affect the opening pressure of the explosion-proof valve.

[0076] For example, in this embodiment, the value of G mm can be 24.2 mm or 24.7 mm or 25.1 mm or 25.8 mm or 26.3 mm or 26.9 mm or 27.2 mm or 27.6 mm or 28.1 mm or 28.4 mm, or it can be any range formed by any two of the above values.

[0077] In one embodiment, α° satisfies 90°≤α°≤150°.

[0078] If the tilt angle α is too small, the angle between the side wall 133 and the bottom wall 132 of the tank is close to a right angle, and the stress is highly concentrated at the sharp corner. The local stress is large, and it is easy to crack locally from the sharp corner before the rated burst pressure is reached, causing the explosion-proof valve to open prematurely. If the tilt angle α is too large, although it can disperse the stress at the corner formed between the side wall 133 and the bottom wall 132 of the tank and reduce the stress concentration problem, it will lead to the overall tear resistance of the weak point being too high. After the set burst pressure is reached, the score is still difficult to tear smoothly, and the internal high pressure cannot be released in time, which poses a risk of shell pressure buildup and cracking.

[0079] For example, in this embodiment, the value of α° can be 106°, 112°, 118°, 125°, 131°, 136°, 140°, 143°, or 146°, or it can be any range formed by any two of the above values.

[0080] In one embodiment, the maximum distance between the bottom wall 132 of the groove and the first surface 11 in the direction perpendicular to the first surface 11 is H mm, satisfying 1.02≤H / h≤1.33.

[0081] If the H / h ratio is too small, it indicates that the groove depth is insufficient, the residual wall thickness is too large, the tear resistance of end wall 1 is too strong, and the groove is still difficult to break after the internal pressure rises to the rated burst value. The high pressure gas cannot be released normally, which can easily cause the casing to burst and the electrolyte to leak. If the H / h ratio is too large, the groove depth is too deep, the residual wall thickness is too thin, the rigidity of the weak part of end wall 1 is insufficient, and the normal internal pressure generated by the normal operation of the battery or the vibration or slight external force will cause the groove to break prematurely, and the explosion-proof valve will open abnormally and leak.

[0082] For example, in this embodiment, the value of H / h can be 1.02 or 1.08 or 1.11 or 1.15 or 1.19 or 1.22 or 1.24 or 1.26 or 1.28 or 1.33, or it can be a range formed by any two of the above values.

[0083] In one embodiment, the area of ​​the pattern formed by the grooves 13 projected onto the end wall 1 along a direction perpendicular to the first surface 11 is M mm. 2 The area of ​​end wall 1 is N mm. 2 The condition is satisfied that 0.32≤M / N≤0.52.

[0084] If the M / N value is too small, the weak area formed by the scribe line will be too small. When the internal pressure of the casing reaches the rated burst pressure, the explosion-proof valve will still be difficult to open smoothly and cannot release the high pressure inside the casing in time, which may cause the casing to burst and generate safety hazards such as electrolyte splashing. If the M / N value is too large, the weak area formed by the scribe line will account for too high a proportion, resulting in insufficient overall structural strength of the end wall 1. This may cause the explosion-proof valve to burst prematurely before the internal pressure of the casing reaches the burst value, resulting in battery leakage and failure.

[0085] For example, in this embodiment, the value of M / N can be 0.36, 0.39, 0.41, 0.43, 0.45, 0.46, 0.48, 0.49, or 0.50, or it can be any range formed by any two of the above values.

[0086] In one embodiment, the groove 13 is annular, or the groove 13 is one or more arc segments. When the groove 13 includes multiple arc segments, the multiple arc segments are sequentially arranged end to end and enclose to form a non-closed annular trajectory.

[0087] For example, the groove 13 is a complete annular groove connected end to end on the end wall 1. When the gas pressure inside the housing reaches the explosion pressure of the explosion-proof valve, the explosion-proof valve separates from the end wall 1 along the entire groove 13, or partially connects to form a flip-top structure. The explosion-proof area is opened outward as a whole to form a pressure relief channel. The high-pressure gas generated by thermal runaway can be ejected outward from the opening formed after the explosion-proof valve is opened.

[0088] Alternatively, the groove 13 can be an arc segment with remnants at both ends connected to the end wall 1. The arc length of the arc segment is greater than the length of the ungrooved remnant connection at both ends. When the internal gas pressure of the housing rises to the set burst pressure, the explosion-proof valve tears along the arc groove. The remnants are still connected to the end wall 1, and the entire explosion-proof valve tilts outward. The high-pressure gas generated by thermal runaway can be ejected outward from the opening formed after the explosion-proof valve tilts outward, preventing the explosion-proof valve from flying out during the explosion and causing damage to the surrounding batteries or parts.

[0089] Alternatively, the groove 13 can be composed of multiple arc segments arranged circumferentially along the explosion-proof area, with ungrooved remnants remaining between adjacent arc segments. The arc length of each arc segment is greater than the length of the remnant. When the internal gas pressure rises to the set burst pressure, each arc segment tears simultaneously, with only the connection between the arc segments maintaining the connection between the explosion-proof valve and the end wall 1. The explosion-proof valve as a whole is multi-lobed and tilted outward, forming multiple dispersed pressure relief openings. These multiple pressure relief openings can disperse the pressure relief airflow, preventing the high-pressure gas inside the casing from being concentrated and instead dividing it into multiple airflows, reducing the impact on surrounding batteries or components.

[0090] In one embodiment, the shell comprises titanium, and the mass content of titanium in the shell is 99% to 99.9%.

[0091] Titanium has higher strength than aluminum and lower density than steel. Under the same structural strength requirements, the wall thickness of the casing can be reduced, the self-weight of the casing can be reduced, and the weight of the casing can be reduced, effectively improving the energy density of the battery. At the same time, because the casing with added titanium has higher strength, it can reduce the bulging deformation caused by pressure on the casing, thus improving the overall safety performance of the battery.

[0092] In one embodiment, the housing is square or cylindrical.

[0093] For example, the square housing is generally rectangular in shape with flat rectangular end faces. The end wall 1 and bottom wall of the housing are integrally formed. The groove 13 is annular or an arc segment and is located on the end wall 1 at the bottom of the housing. The side walls 2 and end walls 1 of the square housing are flat, which enables the regular arrangement of multiple batteries during the integration and assembly of the battery module, improving the overall space utilization and system energy density of the battery pack.

[0094] Alternatively, the casing can be cylindrical, with the sidewalls 2 and bottom endwalls 1 integrally stamped, and grooves 13 provided on the circular endwalls 1 at the bottom of the casing. When gas is generated and pressurized inside the battery, the internal pressure inside the casing can be evenly distributed along the circumference, avoiding stress concentration at the corners.

[0095] In one embodiment, an injection hole 3 is provided on the end wall 1; The end wall 1 is provided with a reinforcing rib 14, which protrudes into the housing relative to the second surface 12. The end wall 1 has a first protrusion 16 on the side facing the interior of the housing; In a direction parallel to the first surface 11, the groove 13, the reinforcing rib 14 and the first protrusion 16 are arranged sequentially from the injection hole 3 toward the side wall 2.

[0096] According to an embodiment of the present invention, another aspect provides a battery cell, including a battery cell and a housing as described above, wherein the battery cell is disposed within the housing.

[0097] A battery cell is the basic unit that makes up a battery. It can store chemical energy and controllably convert chemical energy into electrical energy. In a recyclable battery cell, the active materials can be activated by charging after discharge, allowing it to continue to be used. Battery cells can be further combined into a battery pack 330. The number of battery cells contained in the battery pack 330 can be adjusted according to the actual application scenario and capacity requirements.

[0098] See Figure 8 , Figure 8A schematic diagram of the battery pack 300 in some embodiments of this application is shown. The battery pack 300 is disposed inside an electric vehicle and can be installed at the bottom, front, or rear of the electric vehicle. The battery pack 300 can provide power support to the electric vehicle, for example, acting as the operating power source for the electric vehicle. The electric vehicle may also be equipped with a controller and a motor. The controller is used to schedule the delivery of electrical energy from the battery pack to the motor to meet the power needs of the electric vehicle during starting, navigation, and driving.

[0099] The battery pack 300, as a rechargeable battery, is the power source for new energy vehicles. The battery pack 300 includes a housing 310 and multiple battery cells housed within the housing 310. The housing 310 provides space for the battery cells and other components, while also providing dustproof, waterproof, and protective functions to the internal components, thereby reducing the adverse effects of external liquids or foreign objects on the effectiveness and performance of the battery cells and other components, effectively extending the service life of the battery pack 300. The shape of the housing is not limited; for example, it can be a cuboid, cylinder, etc.

[0100] The material of the enclosure 310 can also be flexibly selected, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0101] The battery pack 300 in this embodiment includes multiple battery groups 330, with one battery group 330 disposed in each sub-accommodating space. Each battery group 330 includes multiple stacked battery cells, and the stacking direction of the battery cells can be parallel to the plane of the base plate. The battery pack 200 also includes a battery management system (BMS), a thermal management system, an electrical connection system (high-voltage / low-voltage connectors, wiring harnesses, etc.), structural components (shell, brackets, etc.), and protective components, etc., and the above components are placed in the housing 310 and sealed by the cover plate 320 to form a complete functional unit that can directly output electrical energy.

[0102] The Battery Management System (BMS) is used to detect the operating status of the battery pack and its individual cells, and to manage the battery module and its cells. The BMS includes a Battery Management Unit (BMU), a Cell Measurement Circuit (CMC), sensors, and various electronic control devices. The BMS includes at least one processor and a memory. The memory can be built into the BMS or externally located, and can also be remotely configured and connected to the BMS via a network.

[0103] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0104] Measurement of dimensions, thickness, distance, and area: Dimensions, thickness, distance, etc. can be measured using micrometers, calipers, or scanning electron microscopes, and the area can be calculated from the dimensions.

[0105] Battery manufacturing: (1) Preparation of the positive electrode: The prepared positive electrode active material, conductive agent acetylene black, and binder PVDF are mixed, and solvent NMP is added. The mixture is stirred under vacuum until the system is homogeneous to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, air-dried at room temperature, and then transferred to an oven for further drying. Finally, it is cold-pressed and slit to obtain the positive electrode sheet. Specifically, the mass ratio of positive electrode active material: conductive agent: binder satisfies (92~98):(4~1):(4~1).

[0106] (2) Preparation of negative electrode: The negative electrode active material, conductive agent acetylene black, thickener CMC, and binder SBR are mixed, and deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector copper foil, air-dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the negative electrode sheet is obtained. The ratio of negative electrode active material: conductive agent: thickener: binder satisfies (90~96):(4~2):(2~1):(4~1).

[0107] (3) Preparation of electrolyte: 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. Then, fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0108] (4) Preparation of the diaphragm: Polyethylene film is selected as the diaphragm.

[0109] (5) Preparation of the shell: Powder metallurgy is used to prepare titanium-containing blanks from titanium powder, carbon powder and other elemental components (such as iron, oxygen, nitrogen, carbon and sulfur), and then hot stamping is used to form the blanks.

[0110] (6) Preparation of lithium-ion batteries: The positive electrode, separator, and negative electrode are stacked in sequence and wound to form a bare battery cell. The bare cell is then placed in a cylindrical battery casing. The battery is dried, injected with electrolyte, and then packaged, allowed to stand, formed, and volume-adjusted to obtain a lithium-ion battery.

[0111] The positive electrode active material can be selected from one or more lithium-containing positive electrode active materials, including lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate; the negative electrode active material can be selected from one or more negative electrode active main materials, such as artificial graphite, natural graphite, silicon carbide, silicon oxide, and lithium titanate.

[0112] The adhesive includes, but is not limited to, one or more combinations of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, carboxymethyl chitosan, etc.

[0113] The solvent can be deionized water, NMP (N-methylpyrrolidone), alcohol, ether, ketone or other types of pyrrolidone, etc.

[0114] The positive electrode current collector foil can be a metal foil or a composite current collector. For example, as a metal foil, it can be made of stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium with a silver-plated surface. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0115] The negative electrode current collector foil can be made of stainless steel, copper, aluminum, nickel, carbon electrodes, or titanium, and can be surface-plated with silver. Composite current collectors may include a polymer base layer and a metal layer. Composite current collectors can be formed by forming metal materials (aluminum, aluminum alloys, copper, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on a polymer base material (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0116] Method for manufacturing battery pack 300: Take 80 batteries prepared by the above method, stack them in groups of 20 to form a battery pack 330, and make 4 battery packs 330. The battery packs 330 are glued and fixed to the first plate. The first plate has vent holes in the grooves corresponding to the end walls of the batteries. The glued position avoids the vent holes. A protective plate is set at the vent holes of the first plate to block the vent holes. The second plate is set on the side of the first plate away from the battery pack 330. The first plate and the second plate form an exhaust channel. The first plate and the second plate are sealed and fixed to the frame. The explosion-proof valve of the box is fixed to the frame. The explosion-proof valve of the box is connected to the explosion-proof valve of the battery through the exhaust channel. The box cover is sealed and fixed to the frame to obtain the battery pack 300.

[0117] The testing method is as follows: Performance 1: Adjacent Battery Thermal Runaway Test. This test measures how long it takes for adjacent batteries to experience thermal runaway when the explosion-proof valve of one battery bursts. The method is as follows: According to the above-described method for preparing the battery pack 300, one battery pack 300 was prepared for each embodiment and comparative example. The values ​​for each embodiment and comparative example are shown in Table 1 below. Except for the above, the structures are the same. In the battery packs 300 of each embodiment and comparative example, heating elements are provided on the two large surfaces opposite to the battery furthest from the explosion-proof valve of the enclosure. The heating elements are located between the heat insulation component and the large surface of the battery. Each battery in the battery pack 300 is charged to the upper limit voltage of 4.25V at a charging rate of 0.33C. The battery is heated at a heating rate of 5±2℃ / min until the battery with the heating element in the battery pack 300 of each embodiment and comparative example experiences thermal runaway. Timing starts from the time the battery experiences thermal runaway, and the time when other batteries in the battery pack 300 experience thermal runaway is observed and recorded. If the time when other batteries experience thermal runaway is greater than or equal to 120 minutes, the test result is qualified. If the time when other batteries experience thermal runaway is less than 120 minutes, the test result is unqualified.

[0118] The positive electrode active material used in this test was selected from LiNi. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, all other positive electrode materials meet the above test requirements. The mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2. The negative electrode active material is selected from artificial graphite, and all other negative electrode materials meet the above test requirements. The ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2. The cell style is selected as a wound cell, and all other cell types meet the above test requirements. The battery casing adopts a cylindrical casing, and all other casing types meet the above test requirements.

[0119] Performance 2, the burst pressure test when the battery valve is opened, the method is as follows: According to the above battery preparation method, corresponding lithium-ion batteries were prepared for each embodiment and comparative example. The number of lithium-ion batteries corresponding to each embodiment was 20. The parameters of the lithium-ion batteries obtained in each embodiment and comparative example are shown in Table 1. Apart from that, the other structures are the same.

[0120] The testing steps are as follows: (1) Pressure holding test: Install the battery into the explosion / pressure withstand test fixture, use AB glue to seal the air tube to the injection hole, connect the air inlet to the explosion instrument, adjust to the pressure holding mode, inflate to a certain pressure from the air tube, maintain for 30s, and then conduct an air tightness test under this pressure to determine the pressure bearing capacity of the casing. (2) Air tightness test: After the pressure holding test, the battery is subjected to a helium leak test. If the leakage rate is ≤1×10 -7 Pa.m 3 If / s, then the battery's pressure resistance is qualified under that pressure.

[0121] (3) The pressure-bearing capacity of the explosion-proof valve is required to be greater than or equal to a certain value (the pressure-bearing capacity of each embodiment and comparative example is 0.6 MPa), that is, under the corresponding value of the shell pressure-bearing capacity air pressure, the leakage rate is ≤1×10 -7 Pa.m 3 / s, the explosion-proof valve has qualified pressure resistance. When the battery is under the corresponding pressure resistance value of the casing, the leakage rate is greater than 1×10. -7 Pa.m 3 When the pressure is / s, it indicates that the pressure-bearing capacity of the explosion-proof valve is less than the corresponding value, and the pressure-bearing capacity of the explosion-proof valve is unqualified. If the pressure-bearing capacity pass rate of each embodiment or comparative example is greater than 90%, it is considered qualified; otherwise, it is considered unqualified.

[0122] The positive electrode active material used in this test was selected from LiNi. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, other positive electrode active materials all meet the above test requirements, and the mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2; the negative electrode active material is selected from artificial graphite, and other negative electrode active materials all meet the above test requirements, and the mass ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0123] The example table is as follows: Table 1

[0124] Regarding Table 1 above, the explanation is as follows: As can be seen from Examples 1-11, when the formula for h / α satisfies the range of 3.5 × 10 -4 ≤h / α≤1.05×10-3 When the battery was tested for thermal runaway between adjacent batteries, all test results were qualified and no failures were found; when the battery was tested for burst pressure when the valve was opened, all test results were qualified and no failures were found; the performance requirements are met.

[0125] In Comparative Example 1, the value of h / α in the formula is lower than the lower limit. The test result is qualified after the thermal runaway test of adjacent batteries. However, the test result is unqualified after the burst pressure test when the battery valve is opened, and the performance requirements cannot be met.

[0126] In Comparative Example 2, the value of h / α in the formula is lower than the lower limit. The test result is qualified after the thermal runaway test of adjacent batteries. However, the test result is unqualified after the burst pressure test when the battery valve is opened, and the performance requirements cannot be met.

[0127] In Comparative Example 3, the value of h / α exceeded the upper limit. The test result was unqualified after testing the thermal runaway of adjacent batteries, but qualified after testing the burst pressure when the battery valve was opened. However, the performance requirements could not be met.

[0128] In addition to titanium, the casing also contains carbon, with the carbon content ranging from 0.01% to 0.08% of the total mass of all elements in the casing. The carbon content is controlled by the amount of carbon powder incorporated. The casing may also contain other elements, the mass content of which is controlled by the amount of powder (such as iron, oxygen, nitrogen, carbon, and sulfur). For example, the Fe content ranges from 0.006% to 0.3% of the total mass of all elements in the casing; the O content ranges from 0.005% to 0.25%; the N content ranges from 0.001% to 0.05%; and the S content ranges from 0.0002% to 0.01%. The more other elements are incorporated in powder form, the lower the carbon content in the casing; conversely, the less other elements are incorporated in powder form, the higher the carbon content in the battery casing.

[0129] Test method for the mass content ratio of each element: The mass content of each element in the battery casing is tested according to GB / T 17359-2023 standard, and the element content ratio is calculated.

[0130] According to an embodiment of the present invention, in another aspect, an electrical device is also provided, including an electrical device body and a battery cell as described above that is electrically connected to the electrical device body.

[0131] In this embodiment, the electrical equipment includes a wide range of technical fields such as energy storage devices, electric ships, aircraft, laptops, power tools, electric bicycles, electric motorcycles, electric cars, military equipment, and aerospace.

[0132] In some embodiments, one or more battery packs 300 constitute a battery device 500. The battery packs 300 can be connected in series, parallel, or a hybrid configuration, where a hybrid configuration refers to the simultaneous presence of series and parallel connections in the connection of multiple battery packs 300. In other embodiments, the battery device 500 is a cluster-level battery architecture composed of multiple battery packs 300 connected in series, wherein the number of battery packs 300 in each cluster is strictly configured according to voltage and capacity requirements. More specifically, the battery unit of the battery device 500 includes multiple batteries, some of which are connected in series to form a cluster that meets a preset power supply voltage requirement, and at least one spare battery among the multiple batteries is bypassed.

[0133] The battery device 500 can be used as an operating power source for electrical equipment or as a driving power source for electrical equipment, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0134] The following uses vehicle 400 as a specific example of an electrical appliance for illustration. See also Figure 8 , Figure 8 A schematic diagram of the structure of a vehicle 400 in some embodiments of this application is shown. The vehicle 400 can be a new energy vehicle, encompassing various types such as pure electric vehicles, hybrid electric vehicles, and range-extended electric vehicles. The battery pack 300 can be located at the bottom, front, or rear of the vehicle 400, providing electrical support to the vehicle 400, for example, acting as the operating power source for the vehicle 400. Furthermore, the vehicle 400 typically also includes a controller 410, which manages the discharge process of the battery device 500 to cover various power needs during vehicle 400 startup, navigation, and driving.

[0135] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A housing, characterized in that, The housing is adapted to accommodate the battery cell. The housing includes an end wall (1) with a maximum wall thickness difference of A mm, satisfying: A mm ≤ 0.25 mm. The end wall (1) includes a first surface (11) and a second surface (12), which are arranged opposite to each other. The end wall (1) has a groove (13) recessed towards the second surface (12) on the first surface (11). The groove (13) includes a bottom wall (132) and two side walls (133), which are inclined relative to the bottom wall (132). The included angle between the bottom wall (132) and any one of the side walls (133) towards the groove (13) is α°. The minimum distance between the bottom wall (132) and the second surface (12) is h mm, satisfying 3.5 × 10⁻⁶ mm. -4 ≤h / α≤1.05×10 -3 .

2. The housing according to claim 1, characterized in that, The minimum distance h mm between the bottom wall (132) of the groove and the second surface (12) satisfies 0.05 mm ≤ h mm ≤ 0.1 mm.

3. The housing according to claim 1, characterized in that, The second surface (12) is located on the side of the end wall (1) facing the interior of the housing.

4. The housing according to claim 1, characterized in that, In the direction parallel to the first surface (11) and perpendicular to the extension of the groove (13), the width of the projection of the groove bottom wall (132) onto the first surface (11) is B mm, satisfying 0.13 mm ≤ B mm ≤ 0.35 mm.

5. The housing according to claim 4, characterized in that, The groove (13) includes a slot (131), which is located at one end of the groove (13) away from the bottom wall (132). The width of the slot (131) is defined as C mm in the extension direction parallel to the first surface (11) and perpendicular to the groove (13), satisfying 0.25≤CB≤0.

57.

6. The housing according to claim 3, characterized in that, The end wall (1) is provided with a reinforcing rib (14), which protrudes into the housing relative to the second surface (12), and the reinforcing rib (14) has a recess (141) on the side away from the second surface (12).

7. The housing according to claim 6, characterized in that, The housing also includes a sidewall (2) adapted to enclose the end wall (1) to form a receiving space, and the scoring groove (13) is disposed on the side of the reinforcing rib (14) away from the sidewall (2); in the extension direction parallel to the first surface (11) and perpendicular to the scoring groove (13), the minimum distance between the reinforcing rib (14) and the scoring groove (13) is K mm, satisfying that 2 mm ≤ K mm ≤ 7 mm.

8. The housing according to claim 6, characterized in that, In the direction parallel to the first surface (11) and perpendicular to the extension of the reinforcing rib (14), the width of the reinforcing rib (14) is D mm, satisfying that 1 mm ≤ D mm ≤ 5 mm.

9. The housing according to claim 1, characterized in that, The housing also includes a sidewall (2), and the endwall (1) forms a first protrusion (16) on the side facing the interior of the housing. The first protrusion (16) is provided with a groove (15) on the side facing away from the interior of the housing. In the extension direction parallel to the first surface (11) and perpendicular to the groove (13), the minimum distance between the groove (15) and the groove (13) is E mm, which satisfies 5 mm ≤ E mm ≤ 9 mm.

10. The housing according to claim 9, characterized in that, The distance between the side of the first protrusion (16) facing the inside of the housing and the second surface (12) is F1 mm; The end wall (1) is provided with reinforcing ribs (14), and the reinforcing ribs (14) protrude into the housing relative to the second surface (12); The distance between the surface of the reinforcing rib (14) facing the inside of the shell and the second surface (12) is F2 mm, which satisfies that F1 mm > F2 mm.

11. The housing according to claim 9, characterized in that, In the extension direction parallel to the first surface (11) and perpendicular to the first protrusion (16), the width of the first protrusion (16) is 1 mm, satisfying 3 mm ≤ 1 mm ≤ 10 mm.

12. The housing according to claim 1, characterized in that, The end wall (1) is provided with an injection hole (3). In the extension direction parallel to the first surface (11) and perpendicular to the groove (13), the minimum distance between the injection hole (3) and the groove (13) is G mm, which satisfies 24 mm ≤ G mm ≤ 29 mm.

13. The housing according to any one of claims 1 to 12, characterized in that, The α° satisfies 90°≤α°≤150°.

14. The housing according to any one of claims 1 to 12, characterized in that, In the direction perpendicular to the first surface (11), the maximum distance between the bottom wall (132) of the groove and the first surface (11) is H mm, which satisfies 1.02≤H / h≤1.

33.

15. The housing according to any one of claims 1 to 12, characterized in that, Along a direction perpendicular to the first surface (11), the area of ​​the pattern formed by the grooves (13) projected onto the end wall (1) is M mm. 2 The area of ​​the end wall (1) is N mm. 2 The condition is satisfied that 0.32≤M / N≤0.

52.

16. The housing according to any one of claims 1 to 12, characterized in that, The groove (13) is annular, or the groove (13) is one or more arc segments. When the groove (13) includes multiple arc segments, the multiple arc segments are arranged end to end in sequence and enclose to form a non-closed annular trajectory.

17. The housing according to any one of claims 1 to 12, characterized in that, The shell includes titanium, and the mass content of titanium in the shell is 99% to 99.9%.

18. The housing according to any one of claims 1 to 12, characterized in that, The shell is square or cylindrical.

19. The housing according to any one of claims 1 to 12, characterized in that, The end wall (1) is provided with a liquid injection hole (3); The end wall (1) is provided with reinforcing ribs (14), and the reinforcing ribs (14) protrude into the housing relative to the second surface (12); The end wall (1) has a first protrusion (16) on the side facing the interior of the housing. In a direction parallel to the first surface (11), the groove (13), the reinforcing rib (14) and the first protrusion (16) are arranged sequentially from the injection hole (3) toward the side wall (2).

20. A single battery cell, characterized in that, It includes a battery cell and a housing as described in any one of claims 1 to 19, wherein the battery cell is disposed within the housing.

21. An electrical appliance, characterized in that, It includes the main body of the electrical equipment and the battery cell as described in claim 20, which is electrically connected to the main body of the electrical equipment.

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