Battery, battery pack, and electric device

Abstract

The application relates to the technical field of batteries, and discloses a battery, a battery pack and a power utilization device, which comprise a shell assembly, a shell and a cover plate, at least one end of the shell is formed with an opening part, the cover plate and the shell are welded to form a first welding mark, the cover plate blocks the opening part and forms an accommodating space together with the shell, an explosion-proof valve, the shell assembly has a first shell wall, the explosion-proof valve is arranged on the first shell wall, the explosion-proof valve has a thinning area, and a battery cell is arranged in the accommodating space; wherein a gas hole is formed in the first welding mark, the average pore diameter of the gas hole is d, the thickness of the thinning area is h, the volume energy density of the battery is V, and 3.8 <= d * h * V <= 119.3 is satisfied. When the battery is in thermal runaway, the application can ensure that the explosion-proof valve is preferentially opened, realize timely and directional pressure relief of the battery, ensure the predetermined valve opening pressure of the explosion-proof valve, avoid the explosion-proof valve from being opened in advance or accidentally, and ensure the reliability of the explosion-proof valve.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to batteries, battery packs, and electrical devices. Background Technology

[0002] As battery technology continues to advance, the requirements for its safety performance are also increasing. Therefore, explosion-proof valves are typically installed on the battery casing. When a battery experiences thermal runaway due to abnormal conditions such as a short circuit or impact, the high-temperature, high-pressure gas generated inside will rupture the explosion-proof valve, thereby achieving timely and directional pressure relief and effectively preventing serious safety accidents such as battery explosions. However, in existing technologies, under the influence of high-temperature, high-pressure gas inside the battery, there is a risk that the weld lines on the casing may rupture along with or even before the explosion-proof valve, preventing the high-temperature, high-pressure gas from being discharged in a directional manner and potentially triggering a chain reaction of thermal runaway in adjacent batteries. Summary of the Invention

[0003] This invention provides a battery, a battery pack, and an electrical device to solve the safety risks in the prior art, such as the inability of high-temperature and high-pressure gases inside the battery to be discharged in a directional manner, which can lead to a chain reaction of thermal runaway in adjacent batteries.

[0004] In a first aspect, the present invention provides a battery comprising: A housing assembly includes a housing and a cover plate, wherein at least one end of the housing is formed with an opening, the cover plate is welded to the housing to form a first weld mark, and the cover plate seals the opening and encloses the housing to form an accommodating space; An explosion-proof valve, wherein the housing assembly has a first housing wall, the explosion-proof valve is disposed on the first housing wall, and the explosion-proof valve has a thinning region; The battery cell is disposed within the accommodating space; The first solder mark contains pores with an average pore diameter of d mm, the thinning region has a thickness of h mm, and the volumetric energy density of the battery is V Wh / L, satisfying 3.8≤d×h×V≤119.3.

[0005] Beneficial effects: By limiting the relationship between the average pore diameter d mm, the thickness h mm of the thinned zone, and the volumetric energy density V Wh / L of the battery, the explosion-proof valve can be guaranteed to open first when the battery experiences thermal runaway. This allows the high-temperature and high-pressure gas inside the battery to be discharged in a directional manner, achieving timely and directional pressure relief of the battery and avoiding chain thermal runaway of adjacent batteries. At the same time, the predetermined opening pressure of the explosion-proof valve is guaranteed, preventing premature or accidental opening of the explosion-proof valve and ensuring its reliability. Specifically, if the value of d×h×V is too large, the first weld mark may crack during battery thermal runaway, causing the high-temperature and high-pressure gas inside the battery to rush out from the crack. This prevents the directional discharge of the high-temperature and high-pressure gas, leading to thermal propagation. Consequently, adjacent batteries may also experience thermal runaway under the influence of the high-temperature and high-pressure gas, resulting in a more serious safety accident. If the value of d×h×V is too small, the structural strength of the explosion-proof valve may be insufficient, resulting in a decrease in the valve's opening pressure. This could cause the explosion-proof valve to open prematurely, and it could also cause the explosion-proof valve to open unexpectedly when the battery is subjected to collisions or impacts.

[0006] Secondly, the present invention also provides a battery pack comprising a plurality of the aforementioned batteries.

[0007] Thirdly, the present invention also provides an electrical device including the aforementioned battery pack. Attached Figure Description

[0008] 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.

[0009] Figure 1 This is a schematic cross-sectional view of a battery along its length and height directions according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the side welding structure of the shell and cover plate according to an embodiment of the present invention; Figure 3 This is a schematic cross-sectional view of the first solder mark in the direction perpendicular to the penetration depth according to an embodiment of the present invention; Figure 4 This is a cross-sectional view of the first solder mark along the penetration depth and penetration width directions according to an embodiment of the present invention. Figure 5 This is a schematic diagram of the structure of a battery according to an embodiment of the present invention; Figure 6 for Figure 5 A top view of the battery shown; Figure 7 for Figure 6 A cross-sectional view along the AA direction; Figure 8 This is a cross-sectional view of another battery along the length and height directions according to an embodiment of the present invention; Figure 9 for Figure 8 The diagram shows the battery from below. Figure 10 for Figure 8 The diagram shows a top view of the battery structure. Figure 11 This is a cross-sectional view of another battery according to an embodiment of the present invention, along its length and height. Figure 12 This is a schematic diagram of the structure of another battery according to an embodiment of the present invention; Figure 13 for Figure 12 A top view of the battery shown; Figure 14 for Figure 13 Cross-sectional view along the BB direction; Figure 15 This is a schematic diagram showing the dimensions of the first shell wall and the thinning region in an embodiment of the present invention; Figure 16 This is a schematic diagram of the structure of another battery according to an embodiment of the present invention; Figure 17 This is a schematic diagram of the structure of a battery pack according to an embodiment of the present invention; Figure 18 The curve showing the ultimate stress on the first weld and the explosion-proof valve as a function of temperature.

[0010] Explanation of reference numerals in the attached figures: 1. Housing assembly; 11. Housing; 12. Cover plate; 121. First side; 13. First weld mark; 131. Vent; 1311. First long shaft; 1312. First short shaft; 132. Long side weld mark; 133. Short side weld mark; 14. First housing wall; 141. Second side; 142. Third side; 143. Through hole; 144. Protrusion; 1441. Inner circumferential surface; 1442. Receiving groove; 145. Reinforcing part; 146. Second surface; 2. Explosion-proof valve; 21. Thinning area; 211. First end; 212. Second end; 213. Arc segment; 214. Straight segment; 22. Groove; 23. Connecting section; 24. Opening part; 241. First surface; 3. Battery cell; 4. Terminal post; 10. Battery; 100. Battery pack. Detailed Implementation

[0011] 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.

[0012] The following is combined with Figures 1 to 18 The following describes embodiments of the present invention.

[0013] According to an embodiment of the present invention, in one aspect, a battery 10 is provided, comprising: The housing assembly 1 includes a housing 11 and a cover plate 12. At least one end of the housing 11 has an opening. The cover plate 12 is welded to the housing 11 to form a first weld mark 13. The cover plate 12 seals the opening and encloses the housing 11 to form an accommodating space. The explosion-proof valve 2 has a housing assembly 1 with a first housing wall 14, the explosion-proof valve 2 is disposed on the first housing wall 14, and the explosion-proof valve 2 has a thinning region 21; Battery cell 3 is housed within the receiving space; Among them, the first solder mark 13 has pores 131 formed in it, the average pore diameter of the pores 131 is d mm, the thickness of the thinning region 21 is h mm, the volumetric energy density of the battery 10 is V Wh / L, which satisfies 3.8≤d×h×V≤119.3.

[0014] The battery 10 of this embodiment, by limiting the relationship between the average pore diameter d mm of the pores 131, the thickness h mm of the thinning region 21, and the volumetric energy density V Wh / L of the battery 10, ensures that the explosion-proof valve 2 opens preferentially when the battery 10 experiences thermal runaway. This allows the high-temperature and high-pressure gas inside the battery 10 to be discharged in a directional manner, achieving timely and directional pressure relief of the battery 10 and avoiding chain thermal runaway of adjacent batteries 10. At the same time, it ensures the predetermined opening pressure of the explosion-proof valve 2, preventing the explosion-proof valve 2 from opening prematurely or accidentally, and ensuring the reliability of the explosion-proof valve 2.

[0015] Specifically, if the values ​​of d×h×V are too large, i.e., the proportions of d, h, or V are too large, the increase in energy density will easily lead to a more severe thermal runaway of battery 10, generating more heat. The strength of the first weld 13 will decrease significantly, and it will be weaker than the thinned area of ​​the explosion-proof valve. The shell assembly 1 is more likely to crack at this point, causing the high-temperature and high-pressure gas inside battery 10 to rush out from the crack in the first weld 13. This prevents the directional discharge of the high-temperature and high-pressure gas, causing thermal propagation. Consequently, adjacent batteries 10 will also experience thermal runaway under the influence of the high-temperature and high-pressure gas, leading to a more serious safety accident. If the values ​​of d×h×V are too small, i.e., the proportions of d, h, or V are too small, although the problem of insufficient strength at the first weld 13 can be reduced, the structural strength of the explosion-proof valve 2 will be weaker. The opening pressure of the explosion-proof valve 2 will decrease, making it easy for the explosion-proof valve 2 to open prematurely before reaching the expected opening pressure. Furthermore, when battery 10 is subjected to collisions or impacts, the explosion-proof valve 2 is also prone to unexpected opening.

[0016] Optionally, d×h×V can be any value from 3.8, 9, 12, 15, 20, 30, 40, 50, 60, 70, 80, 90, 95, 100, 105, 110, 119.3 or a value between any two values.

[0017] It is worth noting that when the battery 10 experiences a short circuit, thermal runaway, or other safety issues, high-temperature and high-pressure gas will be generated inside the battery 10. By setting up the explosion-proof valve 2, when the pressure inside the battery 10 reaches a certain value (that is, the opening pressure of the explosion-proof valve 2), the high-temperature and high-pressure gas will break through the thinned area 21, causing the explosion-proof valve 2 to open and achieve directional pressure relief of the battery 10 at the explosion-proof valve 2.

[0018] However, research has found that, please see Figure 3 and Figure 4 During the welding of the casing 11 and the cover plate 12, pores will form at the weld (i.e., within the weld wire). The presence of pores will reduce the strength of the weld wire itself. Especially when the battery 10 experiences thermal runaway and generates high temperatures, the pores within the weld wire will increase in size and number under the influence of temperature. Under the influence of pores, the strength of the weld wire area will decrease sharply. Figure 18As shown, research has found that the strength of metallic materials decreases significantly at high temperatures. Due to air bubbles within the weld wire, the strength decreases more rapidly with rising temperatures than that of the explosion-proof valve. Therefore, the high temperatures during thermal runaway can cause a sharp drop in weld wire strength, even to the point where the weld wire strength approaches or falls below the strength of the thinned region 21 in the explosion-proof valve 2. Consequently, under the influence of high-temperature, high-pressure gas inside the battery 10, the weld between the casing 11 and the cover plate 12 is prone to rupture along with or even before the explosion-proof valve 2. This prevents the high-temperature, high-pressure gas from being directionally discharged through the explosion-proof valve 2, making it more likely to impact adjacent batteries and other components in the battery pack. The ruptured casing 11 and cover plate 12 can also easily lead to safety issues.

[0019] As mentioned above, the porosity in the weld line formed by the welding of the shell and the cover plate is a key factor affecting the weld line strength. Furthermore, research shows that the thickness of the thinning zone 21 on the explosion-proof valve 2 affects the opening pressure of the explosion-proof valve 2, and the volumetric energy density of the battery 10 affects the heat generation inside the battery 10. Specifically, when the average pore diameter d mm of the pores 131 in the first weld mark 13 is too large, the strength of the weld line formed by the welding of the shell and the cover plate is already difficult to guarantee. If the volumetric energy density V Wh / L of the battery 10 is also too large, it will lead to excessive heat generation during battery thermal runaway. The pores in the weld line will increase and enlarge under high temperature, causing a sharp decrease in the strength of the weld line area. Conversely, if the thickness h mm of the thinning zone 21 is also large, the structural strength of the thinning zone will be too high. During battery thermal runaway, the thinning zone will be less likely to be broken than the weld line, causing high-temperature, high-pressure gas to break through the weld line of the shell and the cover plate, failing to meet the directional pressure relief requirements. Therefore, in this embodiment, by comprehensively controlling the average pore diameter d mm of the pores 131 in the first weld 13, the thickness h mm of the thinning region 21, and the volumetric energy density V Wh / L of the battery 10, the strength of the first weld 13 can be made significantly better than that of the thinning region 21, ensuring that the explosion-proof valve 2 opens first in the event of thermal runaway of the battery 10 and timely directional pressure relief. It can also ensure the reliability of the explosion-proof valve 2 itself and avoid problems such as premature valve opening or accidental valve opening.

[0020] In one embodiment, such as Figure 3 As shown, in a cross-section perpendicular to the penetration direction of the first solder joint, the pore 131 has a first major axis 1311 and a first minor axis 1312. The length of the first major axis 1311 is a mm, and the length of the first minor axis 1312 is b mm, satisfying a mm > b mm. That is, the pore 131 is usually an ellipsoid, rather than a standard sphere.

[0021] It is worth noting that, such as Figure 3As shown, in the cross-section perpendicular to the penetration direction of the first weld 13, the cross-sectional shape of the pore 131 is not usually a standard circle. Therefore, a first major axis 1311 and a first minor axis 1312 are formed on the cross-section of the pore 131. The first major axis 1311 is the axis with the longest length on the cross-section of the pore 131, and the first minor axis 1312 is the axis with the shortest length on the cross-section of the pore 131.

[0022] Furthermore, in this embodiment, the length a mm of the first major axis 1311 and the length b mm of the first minor axis 1312 satisfy 0.33 ≤ b / a < 1. This setting avoids the first major axis 1311 being too long, which would result in it being too close to the adjacent vent 131. This prevents the vent 131 from increasing in volume under the high temperature of thermal runaway of the battery 10, thus avoiding the connection of adjacent vents 131 to form a larger vent 131. This ensures the welding strength of the first solder mark 13 and prevents the first solder mark 13 from being broken by the high temperature and high pressure gas inside the battery 10, ensuring directional pressure relief during thermal runaway of the battery 10.

[0023] Optionally, b / a can be any value from 0.33, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 0.99, or a value between any two values.

[0024] Furthermore, since a first major axis 1311 and a first minor axis 1312 are formed on the cross-section of the pore 131 perpendicular to the penetration direction of the first weld mark 13, the distance between adjacent pores 131 will be further reduced in the direction of the first major axis 1311, increasing the risk of large pores forming through connection under high temperature. Therefore, the average pore diameter d mm of the pores 131 is further limited to 0.2 mm ≤ d mm ≤ 0.9 mm, thereby increasing the distance between adjacent pores 131 by further limiting the average pore diameter of the pores 131, reducing the risk of large pores forming through connection between adjacent pores 131 under high temperature, and ensuring the welding strength of the first weld mark 13.

[0025] In one embodiment, such as Figure 4 As shown, along the penetration direction and / or the width direction of the first weld mark 13, the distance between adjacent pores 131 is c mm, satisfying 0.5 mm ≤ c mm ≤ 200 mm. This setting avoids the adjacent pores 131 being too close, thereby preventing the pores 131 from increasing in volume under the high temperature of thermal runaway of the battery 10, which would lead to the connection of adjacent pores 131 to form larger pores 131. This ensures the welding strength of the first weld mark 13, prevents the first weld mark 13 from being ruptured by the high temperature and high pressure gas inside the battery 10, and ensures directional pressure relief during thermal runaway of the battery 10.

[0026] It is worth noting that if the value of c mm is too small, the distance between adjacent pores 131 may be too close, increasing the risk of adjacent pores 131 connecting and forming large pores under high temperature, affecting the welding strength of the first weld mark 13, and increasing the risk of high-temperature and high-pressure gas breaking through the first weld mark 13 when the battery 10 experiences thermal runaway, thus affecting the directional pressure relief of the battery 10. If the value of c mm is too large, a large spacing is required between adjacent pores 131, which is difficult to achieve in the process, affecting processing efficiency and increasing production costs.

[0027] Optionally, c can take any value from 0.5, 10, 20, 50, 80, 100, 110, 120, 150, 180, 200, or a value between any two values.

[0028] It should be noted that pores will be randomly distributed in the fusion zone of the first weld mark formed by the weld depth and weld width. Therefore, pores will be formed along the weld depth direction and / or weld width direction.

[0029] In this embodiment, the test methods for the average pore diameter d of the first weld mark, the dimensions of the first major axis 1311 and the first minor axis 1312 of the pore 131, and the distance c between adjacent pores 131 refer to GB / T 26955-2011 (Destructive testing of welds in metallic materials: macroscopic and microscopic inspection of welds).

[0030] Furthermore, the average pore size *d* within the weld line can be controlled by adjusting the welding process, the materials of the shell and cover plate, and the thickness of the weld joint. For example, when using laser welding, the welding process can be controlled by adjusting the laser power (range: 1000W to 6000W), welding speed (range: 200–400mm / s), defocusing amount (positive defocusing range: +0.5mm to +4mm, negative defocusing range: -0.5mm to -3mm), pulse waveform (sharp wave or double peak wave), and laser oscillation mode (using a "figure-eight" or "elliptical" trajectory). When the shell is made of steel, aluminum, titanium, etc., the proportion of trace doping elements in the shell material, such as Mg, Cu, Cr, Fe, Mn, Zn, C, Si, and N, can be adjusted. For example, in a steel shell, the carbon content is 0.008%–0.02% (low-carbon design improves ductility and stamping performance, avoids embrittlement in the welded area, and reduces the risk of fracture), the manganese content is 0.1%–0.5%, the silicon content is ≤0.03%, the phosphorus content is 0.015%–0.03%, the sulfur content is 0.0020%–0.03%, and the aluminum content is 0.050%–0.10%; in an aluminum shell, the manganese content is 1.0%–1.5%, the iron content is ≤0.7%, the silicon content is ≤0.6%, the magnesium content is 2.2%–4.9%, the copper content is ≤0.10%, the zinc content is 0.10%, and the titanium content is ≤0.15%; in a titanium shell, the aluminum content is 5.5%–6.5%, and the vanadium content is 3.5%–4.5%. The above-mentioned control method can also be used to control the size and ratio of the first major axis 1311 and the first minor axis 1312 of the vent 131, as well as the distance c between adjacent vents 131.

[0031] Specifically, in one embodiment, such as Figure 1 and Figure 2 As shown, the penetration depth of the first weld 13 is e mm, satisfying 0.3 mm ≤ e mm ≤ 2 mm; the penetration width of the first weld 13 is f mm, satisfying 0.6 mm ≤ f mm ≤ 3 mm. This setting ensures the welding strength of the first weld 13 while guaranteeing the overall quality of the shell 11 and cover plate 12 after welding.

[0032] It is worth noting that if the values ​​of e mm and f mm are too small, the welding strength of the first weld mark 13 may be insufficient, increasing the risk that high-temperature and high-pressure gas will break through the first weld mark 13 during thermal runaway of the battery 10, thus affecting the directional pressure relief of the battery 10. If the values ​​of e mm and f mm are too large, the casing 11 or cover plate 12 may be welded through during welding, affecting the overall quality of the casing 11 and cover plate 12 after welding.

[0033] Optionally, e can take any value from 0.3, 0.4, 0.5, 0.8, 1, 1.2, 1.5, 1.8, 2, or a value between any two values.

[0034] Optionally, f can take any value from 0.6, 0.8, 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, or a value between any two values.

[0035] It should be noted that, as Figure 1 As shown, the housing 11 and the cover plate 12 can be welded together using top welding; as Figure 2 As shown, the housing 11 and the cover plate 12 can also be welded together by side welding.

[0036] In this embodiment, the penetration depth and width of the first weld mark are measured using metallographic analysis. A cross-sectional sample of the weld (first weld mark) is prepared, and the penetration depth and width are directly observed and quantified under an optical microscope. The measurement method and implementation process are as follows: (a) Sampling: From the welded battery casing, along the direction perpendicular to the weld, use a cutting machine (e.g., Beta-300Pro) with a silicon carbide (SiC) cutting disc to cut a sample containing the complete weld in a low-speed pulse mode (6A, 0.6mm / s, 2200rpm) to avoid deformation of the heat-affected zone.

[0037] (ii) Embedding: TJ2210 acrylic resin or TJ2568 epoxy resin are preferred. Apply 0.3MPa pressure for 15 minutes in a pressure cold embedding machine (e.g., Theta Mount pressure cold embedding machine) to avoid thermal stress damaging the microstructure of the weld.

[0038] (III) Grinding and polishing: Use a grinding and polishing machine (such as GP-2000A) to grind step by step in the order of gradient sandpaper (P400 grit → 800 grit → 1200 grit → 2500 grit), and finally use 0.05μm alumina polishing liquid to obtain a mirror surface, ensuring that the weld interface is clearly visible.

[0039] (iv) Corrosion: Soak in 0.01mol / L-0.5mol / L NaOH solution for 30 minutes, or chemically corrode with 10% ammonium persulfate aqueous solution to make the welded area and the heat-affected zone clearly contrast.

[0040] (v) Observation and measurement: Use a stereomicroscope or metallographic microscope to observe the cross-section, and use professional image analysis software to measure the melt depth and melt width.

[0041] It is worth noting that the penetration depth refers to the vertical distance from the surface of the base metal to the deepest melting point of the weld; the weld width refers to the horizontal width of the melting boundary of the base metal on both sides of the weld.

[0042] Furthermore, the weld depth and width can be controlled by adjusting the welding process, the materials of the shell and cover plate, and the thickness of the weld joint. For example, when using laser welding, the welding process can be controlled by adjusting the laser power (range: 1000W to 6000W), welding speed (range: 200–400mm / s), defocusing amount (positive defocusing range: +0.5mm to +4mm, negative defocusing range: -0.5mm to -3mm), pulse waveform (spiky wave or double-peak wave), and laser oscillation mode (using a "figure-eight" or "elliptical" trajectory). When the shell is made of steel, aluminum, titanium, etc., the proportion of trace doping elements in the shell material, such as Mg, Cu, Cr, Fe, Mn, Zn, C, Si, N, etc., can be adjusted.

[0043] Specifically, in one embodiment, the average pore diameter d mm of the pores 131 satisfies 0.2 mm ≤ d mm ≤ 1 mm. This setting increases the distance between adjacent pores 131, reduces the risk of adjacent pores 131 connecting to form large pores under high temperature, ensures the welding strength of the first weld mark 13, prevents the first weld mark 13 from being broken by the high temperature and high pressure gas inside the battery 10, and ensures directional pressure relief in the event of thermal runaway of the battery 10.

[0044] It is worth noting that if the value of d mm is too large, the distance between adjacent pores 131 may become too close, increasing the risk of adjacent pores 131 connecting and forming large pores under high temperature, affecting the welding strength of the first weld mark 13, and increasing the risk of high-temperature and high-pressure gas breaking through the first weld mark 13 during thermal runaway of the battery 10, thus affecting the directional pressure relief of the battery 10. If the value of d mm is too small, the pores 131 need to be smaller, which is difficult to achieve with existing welding processes. Moreover, excessive pursuit of controlling the size of d pores will also affect processing efficiency and increase production costs. Therefore, the lower limit of the value of d mm is selected based on the currently achievable pore size. In addition, it is necessary to add other metal elements that are conducive to welding to the shell 11, which may lead to a weakening of the processing performance and mechanical strength of the shell 11. For example, adding silicon or magnesium to the aluminum shell can significantly lower the melting point of the aluminum alloy, widen the solidification temperature range, and improve the fluidity of the molten pool, thereby effectively inhibiting the formation of pores. However, excessive content can also cause the alloy material to become brittle, potentially leading to cracks during processing. The preferred mass content of silicon in the aluminum alloy shell is 0.5wt%-1.5wt%, and the preferred mass content of magnesium is 0.7wt%-1.3wt%. Simultaneously, the content of elements such as iron and copper must be controlled (e.g., Fe≤0.5wt%, Cu≤0.1wt%) to ensure the purity of the weld pool and the sealing performance of the shell.

[0045] Optionally, d can take any value from 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, or a value between any two values.

[0046] Preferably, the average pore diameter d mm of the pores 131 satisfies 0.2 mm ≤ d mm ≤ 0.5 mm.

[0047] Specifically, in one embodiment, the thickness h mm of the thinning region 21 satisfies 0.04 mm ≤ h mm ≤ 0.3 mm. This configuration ensures that the explosion-proof valve 2 opens preferentially, allowing the high-temperature, high-pressure gas inside the battery 10 to be directionally discharged, achieving timely and directional pressure relief of the battery 10. Simultaneously, it guarantees the predetermined opening pressure of the explosion-proof valve 2, preventing premature or accidental opening and ensuring the reliability of the explosion-proof valve 2.

[0048] It is worth noting that if the value of h mm is too small, the structural strength of the explosion-proof valve 2 may be insufficient, resulting in a decrease in the opening pressure of the explosion-proof valve 2. This could cause the explosion-proof valve 2 to open prematurely, and the explosion-proof valve 2 may open unexpectedly when the battery 10 is subjected to collisions or impacts. If the value of h mm is too large, the opening pressure of the explosion-proof valve 2 may be too large. When the battery 10 experiences thermal runaway, the first weld mark 13 may be subjected to excessive pressure and rupture. This would cause the high-temperature and high-pressure gas inside the battery 10 to rush out from the rupture location of the first weld mark 13, making it impossible to achieve directional discharge of the high-temperature and high-pressure gas. This would trigger a thermal propagation phenomenon, causing adjacent batteries 10 to also experience thermal runaway under the influence of the high-temperature and high-pressure gas, leading to a more serious safety accident.

[0049] Optionally, h can take any value from 0.04, 0.05, 0.08, 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, or a value between any two values.

[0050] Preferably, the thickness h mm of the thinning region 21 satisfies 0.05 mm ≤ h mm ≤ 0.22 mm.

[0051] In this embodiment, measuring instruments such as micrometers or calipers are used to measure parameters such as length, width, distance, and thickness. The area is calculated from the measured parameters such as length, width, distance, and thickness.

[0052] Specifically, in one embodiment, the volumetric energy density V Wh / L of the battery 10 satisfies 300Wh / L ≤ V Wh / L ≤ 460Wh / L. This setting avoids excessive gas generation inside the battery 10, reduces the pressure on the first solder mark 13, thereby reducing the risk of the first solder mark 13 being ruptured and achieving directional pressure relief of the battery 10.

[0053] It is worth noting that if the value of V Wh / L is too high, it can easily lead to excessive gas production inside battery 10, causing the first solder joint 13 to be subjected to excessive pressure and prone to rupture. This allows the high-temperature, high-pressure gas inside battery 10 to escape through the rupture point of the first solder joint 13, preventing the directional discharge of the high-temperature, high-pressure gas and causing thermal propagation. Consequently, adjacent batteries 10 may also experience thermal runaway under the influence of the high-temperature, high-pressure gas, leading to a more serious safety accident. If the value of V Wh / L is too low, it can easily result in insufficient capacity of battery 10, failing to meet the design and usage requirements of battery 10.

[0054] Optionally, V can take any value from 300, 320, 350, 380, 400, 420, 450, 460, or a value between any two values.

[0055] It should be noted that the volumetric energy density of battery 10 is calculated by the ratio of the capacity of battery 10 to the volume of battery 10.

[0056] In this embodiment, the measurement method for the volumetric energy density of the battery refers to standard GB / T 31486-2024. The volumetric energy density V of the battery can be adjusted by increasing the proportion of active material within the battery. For example, this can be achieved by using double-sided coated electrodes, using electrodes with higher compaction density, or controlling the thickness ratio of the active material layer in the electrode thickness. Alternatively, the volumetric energy density can be increased by reducing the volume of other components within the battery.

[0057] Regarding the placement of the explosion-proof valve 2 on the housing assembly 1, the explosion-proof valve 2 can be placed on the cover plate 12, in which case the first housing wall 14 is formed on the cover plate 12; alternatively, the explosion-proof valve 2 can be placed on the housing 11, in which case the first housing wall 14 is formed on the housing 11. The specific implementation methods of placing the explosion-proof valve 2 on the cover plate 12 and on the housing 11 will be described below.

[0058] In the first implementation, such as Figure 1 , Figure 5 , Figure 12 As shown, the thickness of the cover plate 12 is greater than the wall thickness of the housing 11, and the explosion-proof valve 2 is disposed on the cover plate 12. The cover plate 12 is thicker than the housing 11, and placing the explosion-proof valve 2 on the cover plate 12 can make the explosion-proof valve 2 stronger and further ensure the reliability of the explosion-proof valve 2.

[0059] Furthermore, in the first embodiment, such as Figure 7As shown, the minimum distance between the thinning zone 21 and the first weld mark 13 is g mm, satisfying 2.5 mm ≤ g mm ≤ 52 mm. This setting ensures the gas flow area after the explosion-proof valve 2 is opened, while reducing the pulling effect of the explosion-proof valve 2 on the first weld mark 13 when it is opened, preventing the first weld mark 13 from tearing, and ensuring the directional pressure relief of the battery 10.

[0060] It is worth noting that if the value of g mm is too small, when the high-temperature and high-pressure gas inside the battery 10 breaks the explosion-proof valve 2 in the thinning zone 21, the force of the high-temperature and high-pressure gas on the explosion-proof valve 2 will be quickly transmitted to the first weld mark 13, increasing the risk of tearing the first weld mark 13. This would cause the high-temperature and high-pressure gas inside the battery 10 to rush out from the ruptured position of the first weld mark 13, making it impossible to achieve directional discharge of the high-temperature and high-pressure gas, causing thermal propagation. Consequently, adjacent batteries 10 may also experience thermal runaway under the influence of the high-temperature and high-pressure gas, leading to a more serious safety accident. If the value of g mm is too large, it may reduce the setting range of the thinning zone 21, resulting in a smaller gas flow area after the explosion-proof valve 2 is opened. This would not guarantee the rapid depressurization of the battery 10, increasing the risk of explosion of the battery 10.

[0061] Optionally, g can take any value from 2.5, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 52, or a value between any two values.

[0062] Furthermore, in the first embodiment, such as Figure 6 As shown, the length direction of the thinning zone 21 is parallel to the length direction of the cover plate 12. This arrangement increases the setting range of the thinning zone 21, increases the gas flow area after the explosion-proof valve 2 is opened, and achieves rapid pressure relief.

[0063] It is worth noting that, please refer to Figure 15 The area enclosed by the thinning region 21 is typically oblong. Specifically, the thinning region 21 includes two arc segments 213 and at least one straight segment 214. The two arc segments 213 are spaced apart relative to each other along the length of the cover plate 12, and the straight segment 214 extends along the length of the cover plate 12 and connects the two ends of the two arc segments 213 that are spaced apart relative to each other along the length of the cover plate 12. Therefore, the extending direction of the straight segment 214 is the length direction of the thinning region 21.

[0064] It needs to be further explained that, such as Figure 7 and Figure 11As shown, the first solder mark 13 includes a long side solder mark 132 extending along the length direction of the cover plate 12 and a short side solder mark 133 extending along the width direction of the cover plate 12. Therefore, the straight segment 214 and the long side solder mark 132 are arranged in parallel. The minimum distance g mm between the thinning area 21 and the first solder mark 13 is the distance between the straight segment 214 and the long side solder mark 132.

[0065] Of course, as alternative implementation methods, such as Figure 16 As shown, the length direction of the thinning region 21 can also be set parallel to the width direction of the cover plate 12, as long as there is enough layout space in the width direction of the cover plate 12.

[0066] Furthermore, in the first embodiment, such as Figure 6 As shown, the battery 10 also includes a terminal post 4, which is electrically connected to the cell 3. The terminal post 4 is disposed on the cover plate 12, and the minimum distance between the terminal post 4 and the thinning area 21 is i mm, satisfying 50 mm ≤ i mm ≤ 180 mm. This configuration can reduce the risk of premature opening of the explosion-proof valve 2 and improve the reliability of the explosion-proof valve 2.

[0067] It is worth noting that the terminal post 4 is the component in the battery 10 where heat is concentrated. Since both the terminal post 4 and the explosion-proof valve 2 are located on the cover plate 12, the explosion-proof valve 2 is easily affected by the heat from the terminal post 4, which can compromise its strength. If the value of i mm is too small, meaning the distance between the terminal post 4 and the thinning region 21 is too close, the thinning region 21 is more susceptible to the heat from the terminal post 4, leading to a decrease in its strength. This increases the risk of premature opening of the explosion-proof valve 2 and affects its reliability.

[0068] Optionally, the value of i can be any value from 50, 60, 70, 80, 100, 110, 120, 150, 160, 180 or a value between any two values.

[0069] Specifically, such as Figure 6 As shown, there are usually two pole posts 4, which are spaced apart along the length of the cover plate 12, and the explosion-proof valve 2 is located between the two pole posts 4.

[0070] In the second implementation, such as Figures 8 to 10 As shown, the first shell wall 14 is located on the shell 11, and the first shell wall 14 is disposed opposite to the cover plate 12. At this time, the explosion-proof valve 2 and the first solder mark 13 are respectively disposed at opposite ends in the height direction of the battery 10. When the explosion-proof valve 2 is opened, the first solder mark 13 is subjected to less pulling force, which reduces the risk of tearing of the first solder mark 13 and ensures the directional pressure relief of the battery 10.

[0071] Furthermore, in the second embodiment, such as Figure 8As shown, the battery 10 also includes a terminal post 4, which is electrically connected to the cell 3 and is disposed on the cover plate 12. At this time, the terminal post 4 and the explosion-proof valve 2 are located at opposite ends in the height direction of the battery 10, achieving thermoelectric separation of the battery 10. However, the high-temperature and high-pressure gas generated at the end where the terminal post 4 is located is difficult to reach the end where the explosion-proof valve 2 is located, easily causing untimely pressure relief and increasing the risk of the first weld mark 13 being ruptured under the action of high-temperature and high-pressure gas. Therefore, the thickness h mm of the thinning region 21 is made to satisfy 0.04 mm ≤ h mm ≤ 0.25 mm. By further limiting the thickness of the thinning region 21, the opening pressure of the explosion-proof valve 2 is reduced, enabling the explosion-proof valve 2 to open in time to relieve pressure, reducing the pressure on the first weld mark 13, preventing the first weld mark 13 from being ruptured, and ensuring directional pressure relief of the battery 10.

[0072] Furthermore, in the second embodiment, such as Figure 8 As shown, along the arrangement direction of the first shell wall 14 and the cover plate 12, the height of the battery 10 is j mm, satisfying j mm ≥ 120 mm and 3.8 ≤ d × h × V ≤ 10⁵. When the height of the battery 10 is large, the capacity of the battery 10 increases, and the amount of gas generated inside the battery 10 increases. Therefore, the pressure on the first weld mark 13 increases. In addition, the transmission path of high-temperature and high-pressure gas from the end where the electrode post 4 is located to the end where the explosion-proof valve 2 is located is longer, further causing untimely pressure relief and further increasing the risk of the first weld mark 13 being ruptured under the action of high-temperature and high-pressure gas. Therefore, by further limiting the value of d × h × V, the welding strength of the first weld mark 13 is further guaranteed, and the opening pressure of the explosion-proof valve 2 is further reduced, so that the explosion-proof valve 2 can open in time to relieve pressure, reduce the pressure on the first weld mark 13, avoid the first weld mark 13 being ruptured, and ensure the directional pressure relief of the battery 10.

[0073] It is worth noting that, such as Figure 8 As shown, the arrangement direction of the first shell wall 14 and the cover plate 12 is the height direction of the battery 10.

[0074] Furthermore, in the second embodiment, such as Figure 9 and Figure 10As shown, the battery 10 also includes terminals 4, which are electrically connected to the cell 3. Two terminals 4 are provided, spaced apart along the length of the cover plate 12. The cover plate 12 has two first sides 121 arranged opposite each other along its length, with a minimum distance p between the first side 121 and the terminal 4 along its length. The first shell wall 14 has two second sides 141 arranged opposite each other along its length, with a minimum distance q between the second side 141 and the thinning area 21 along its length, satisfying p < q. This arrangement avoids excessive differences in the gas transmission path lengths from the two terminals 4 to the explosion-proof valve 2, ensuring that the high-temperature, high-pressure gas generated at both terminals 4 can smoothly reach the explosion-proof valve 2. This prevents the first weld mark 13 from being broken due to excessive force caused by untimely discharge of high-temperature, high-pressure gas, thus ensuring directional pressure relief of the battery 10.

[0075] Alternatively, as an alternative implementation, the first shell wall 14 can also be the side of the shell 11 that is connected to the cover plate 12, that is, the explosion-proof valve 2 is disposed on the side of the shell 11.

[0076] In one embodiment, such as Figure 1 and Figure 11 As shown, a groove 22 is formed on the side of the thinning area 21 facing the battery cell 3 or on the side away from the battery cell 3. Specifically, the groove 22 is formed by etching (punching or corroding) on ​​the explosion-proof sheet substrate, so that the thickness of the explosion-proof sheet substrate is reduced at the groove 22 to form the thinning area 21.

[0077] It is worth noting that the cross-sectional shape of the groove 22 in the direction perpendicular to the extension path of the thinning zone 21 can be trapezoidal, triangular, U-shaped, or square.

[0078] In one embodiment, such as Figure 11 As shown, the groove 22 is formed on the side of the explosion-proof valve 2 facing the battery cell 3. At this time, the electrolyte in the containment space further corrodes the thinning region 21, and the high-temperature, high-pressure gas inside the battery 10 creates stress concentration at the thinning region 21, increasing the risk of the explosion-proof valve 2 opening. Therefore, the thickness h mm of the thinning region 21 is made to satisfy 0.04 mm ≤ h mm ≤ 0.22 mm. By further limiting the value of h mm, the structural strength of the explosion-proof valve 2 at the thinning region 21 is increased, reducing the risk of premature or accidental opening of the explosion-proof valve 2.

[0079] Additionally, in another embodiment, such as Figure 1As shown, the groove 22 is formed on the side of the explosion-proof valve 2 facing away from the battery cell 3. At this time, the side of the explosion-proof valve 2 facing the battery cell 3 is flat, reducing the impact of the electrolyte on the thinning area 21. Furthermore, the explosion-proof valve 2 is subjected to a more balanced force from the high-temperature, high-pressure gas inside the battery 10, reducing the risk of the explosion-proof valve 2 opening. Therefore, the depth of the groove 22 is set to k mm, satisfying k mm ≥ 0.2 mm. By limiting the depth of the groove 22, in the event of thermal runaway in the battery 10, the explosion-proof valve 2 can be guaranteed to open preferentially, allowing the high-temperature, high-pressure gas inside the battery 10 to be discharged in a directional manner. This achieves timely and directional pressure relief of the battery 10, preventing a chain reaction of thermal runaway to adjacent batteries 10.

[0080] In one embodiment, such as Figure 15 As shown, the thinning region 21 has a partially enclosed annular structure with a first end 211 and a second end 212 formed at both ends along its extension path. The first end 211 and the second end 212 are spaced apart, and a connecting section 23 is formed between the first end 211 and the second end 212. By providing the connecting section 23, when the explosion-proof valve 2 is opened through the thinning region 21, the area enclosed by the thinning region 21 is prevented from flying out, thereby improving the safety of the battery 10.

[0081] It is worth noting that the connecting section 23 is the area where the groove 22 is not formed. The groove 22 and the connecting section 23 together form a complete (i.e., completely closed) annular structure.

[0082] Furthermore, in one embodiment, such as Figure 15 As shown, the first shell wall 14 has two third sides 142 arranged opposite to each other along its width direction. The connecting section 23 and the third sides 142 are arranged opposite to each other and spaced apart along the width direction of the first shell wall 14. When the explosion-proof valve 2 is opened under the action of high-temperature and high-pressure gas, the connecting section 23 will not be torn. The arrangement of the connecting section 23 opposite to the third sides 142 reduces the pulling effect on the third sides 142 when the explosion-proof valve 2 is opened, reducing the risk of tearing of the first solder mark 13 at the third sides 142 and ensuring directional pressure relief of the battery 10.

[0083] In one embodiment, such as Figure 14As shown, the first shell wall 14 has a through hole 143 extending through it along its thickness direction. The first shell wall 14 protrudes in the direction away from the battery cell 3 to form a protrusion 144. The protrusion 144 surrounds the through hole 143 and has an inner circumferential surface 1441. The inner circumferential surface 1441 surrounds the through hole 143. The explosion-proof valve 2 covers the through hole 143 and is fixedly connected to the protrusion 144. The explosion-proof valve 2 is installed on the protrusion 144. When the explosion-proof valve 2 is opened under the action of high temperature and high pressure gas, the force of the high temperature and high pressure gas on the explosion-proof valve 2 is buffered by the protrusion 144 and reaches the position of the first weld mark 13. This reduces the pulling effect on the first weld mark 13 when the explosion-proof valve 2 is opened, avoids the first weld mark 13 from tearing, and ensures the directional pressure relief of the battery 10. In addition, the impact or vibration of the housing 11 is buffered by the protrusion 144 and reaches the explosion-proof valve 2, reducing the force on the explosion-proof valve 2 and preventing the explosion-proof valve 2 from opening accidentally.

[0084] Furthermore, in one embodiment, such as Figure 14 As shown, a receiving groove 1442 is formed around the through hole 143 on the side of the protrusion 144 facing the cell 3, and at least a portion of the explosion-proof valve 2 is disposed in the receiving groove 1442. This arrangement can reduce the space occupied by the explosion-proof valve 2 inside the battery 10, improve the space utilization of the battery 10, and increase the exhaust space between the end face of the cell 3 facing the first shell wall 14 and the first shell wall 14, preventing the explosion-proof valve 2 from being blocked by the end face of the cell 3, improving the gas transmission effect, and facilitating the smooth discharge of gas.

[0085] It is worth noting that the outer periphery of the explosion-proof valve 2 is located in the receiving groove 1442, and the thinning zone 21 is positioned opposite to the through hole 143, so that after the high-temperature and high-pressure gas breaks through the thinning zone 21, it can be discharged through the through hole 143.

[0086] It should be noted that the explosion-proof valve can be completely contained within the receiving groove along the thickness direction of the explosion-proof valve (that is, the thickness direction of the first shell wall). In other words, the thickness of the explosion-proof valve is not greater than the depth of the receiving groove. Of course, the explosion-proof valve can also be partially contained within the receiving groove. In this case, the thickness of the explosion-proof valve is greater than the depth of the receiving groove, and the part of the explosion-proof valve along the thickness direction will protrude from the receiving groove.

[0087] Furthermore, in one embodiment, such as Figure 14 As shown, in the direction perpendicular to the extension path of the thinning region 21, the distance between the thinning region 21 and the inner circumferential surface 1441 is n mm, satisfying 0.1 mm ≤ n mm ≤ 2 mm. This setting ensures effective protection of the explosion-proof valve 2 by the protrusion 144 while guaranteeing the gas flow area after the explosion-proof valve 2 is opened.

[0088] It is worth noting that if the value of n mm is too small, when the explosion-proof valve 2 opens under the action of high-temperature and high-pressure gas, the pulling force of the high-temperature and high-pressure gas on the explosion-proof valve 2 is still relatively large when it is transmitted to the first weld mark 13. This increases the risk of tearing of the first weld mark 13, causing the high-temperature and high-pressure gas inside the battery 10 to rush out from the crack position of the first weld mark 13. This prevents the directional discharge of the high-temperature and high-pressure gas, causing thermal propagation. Consequently, adjacent batteries 10 may also experience thermal runaway under the influence of high-temperature and high-pressure gas, leading to a more serious safety accident. If the value of n mm is too large, it may reduce the setting range of the thinning zone 21, resulting in a smaller gas flow area after the explosion-proof valve 2 opens. This makes it impossible to guarantee the rapid depressurization of the battery 10, increasing the risk of explosion of the battery 10.

[0089] Optionally, n can take any value from 0.1, 0.2, 0.4, 0.5, 0.8, 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2, or a value between any two values.

[0090] It should be noted that the direction perpendicular to the extension path of the thinning region 21 mentioned above refers to the direction perpendicular to the extension direction of the straight segment 214, and to the radial direction of the arc segment 213.

[0091] In one embodiment, such as Figures 12 to 14 As shown, a reinforcing portion 145 is formed on the outer periphery of the explosion-proof valve 2 in the first shell wall 14. The reinforcing portion 145 protrudes towards or away from the battery cell 3. With this configuration, when the explosion-proof valve 2 is opened under the action of high-temperature and high-pressure gas, the force of the high-temperature and high-pressure gas on the explosion-proof valve 2 is buffered by the reinforcing portion 145 and reaches the position of the first solder mark 13. This reduces the pulling effect on the first solder mark 13 when the explosion-proof valve 2 is opened, prevents the first solder mark 13 from tearing, and ensures the directional pressure relief of the battery 10. In addition, the impact or vibration received by the shell 11 is buffered by the reinforcing portion 145 and reaches the explosion-proof valve 2, reducing the force on the explosion-proof valve 2 and preventing the explosion-proof valve 2 from opening accidentally.

[0092] It is worth noting that the reinforcing part can be formed by stamping on the substrate of the first shell wall.

[0093] In one embodiment, such as Figure 14As shown, the explosion-proof valve 2 includes an opening portion 24 formed by a thinning region 21. The side of the opening portion 24 facing away from the battery cell 3 forms a first surface 241, and the side of the first shell wall 14 facing away from the battery cell 3 forms a second surface 146. The first surface 241 is positioned closer to the battery cell 3 than the second surface 146. Along the thickness direction of the first shell wall 14, the distance between the first surface and the second surface is t mm, satisfying 0.4 mm ≤ t mm ≤ 2.85 mm. This arrangement achieves the protective effect of the explosion-proof valve 2 while ensuring the space utilization rate of the battery 10.

[0094] It is worth noting that if the value of t mm is too small, the protective effect of the first shell wall 14 on the explosion-proof valve 2 will be insufficient, increasing the risk of accidental opening of the explosion-proof valve 2 and affecting its reliability. If the value of t mm is too large, the explosion-proof valve 2 may occupy too much space, affecting the space utilization rate of the battery 10.

[0095] Optionally, t can take any value from 0.4, 0.6, 0.8, 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2, 2.2, 2.5, 2.8, 2.85, or a value between any two values.

[0096] In one embodiment, such as Figure 15 As shown, the explosion-proof valve 2 includes an opening portion 24 formed by the thinning region 21. On the projection plane perpendicular to the thickness direction of the first shell wall 14, the orthographic projection area of ​​the first shell wall 14 is S1 mm. 2 The projected area of ​​the opening part 24 is S2 mm. 2 The condition 0.005≤S2 / S1≤0.3 is satisfied. This setting ensures the gas flow area after the explosion-proof valve 2 is opened, while reducing the pulling effect of the explosion-proof valve 2 on the first weld mark 13 when it is opened, avoiding tearing of the first weld mark 13, and ensuring the directional pressure relief of the battery 10.

[0097] It is worth noting that if the values ​​of S2 / S1 are too large, the distance between the thinning zone 21 and the edge of the first shell wall 14 may be too close. When the high-temperature and high-pressure gas inside the battery 10 breaks the explosion-proof valve 2 in the thinning zone 21, the force of the high-temperature and high-pressure gas on the explosion-proof valve 2 will be quickly transmitted to the first weld mark 13, increasing the risk of tearing the first weld mark 13. This would cause the high-temperature and high-pressure gas inside the battery 10 to rush out from the ruptured position of the first weld mark 13, making it impossible to achieve directional discharge of the high-temperature and high-pressure gas, causing thermal propagation. Consequently, adjacent batteries 10 may also experience thermal runaway under the influence of the high-temperature and high-pressure gas, leading to a more serious safety accident. If the values ​​of S2 / S1 are too small, the setting range of the thinning zone 21 may be reduced, resulting in a smaller gas flow area after the explosion-proof valve 2 is opened. This would not guarantee the rapid depressurization of the battery 10, increasing the risk of explosion of the battery 10.

[0098] Optionally, the value of S2 / S1 can be any one of 0.005, 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3 or a value between any two values.

[0099] In one embodiment, the battery cell 3 comprises ternary materials, and the battery 10 has a capacity of not less than 50Ah, satisfying 3.8≤d×h×V≤95.

[0100] It is worth noting that the ternary lithium battery 10 has a higher thermal runaway temperature. Furthermore, when the capacity of the battery 10 is larger, the amount of gas generated inside the battery 10 increases. Therefore, this has a greater impact on the welding strength of the first weld mark 13, and the pressure on the first weld mark 13 increases. By further limiting the values ​​of d×h×V, the welding strength of the first weld mark 13 is further guaranteed, and the opening pressure of the explosion-proof valve 2 is further reduced, enabling the explosion-proof valve 2 to open in a timely manner to release pressure, reducing the pressure on the first weld mark 13, preventing the first weld mark 13 from being ruptured, and ensuring the directional pressure relief of the battery 10.

[0101] For example, the inclusion of ternary materials in cell 3 means that the positive electrode material of cell 3 is lithium nickel cobalt manganese oxide, with the chemical formula LiNi. x Co y Mn z M w O2, where 0 < x < 1, 0 < y < 1, 0 ≤ z < 1, 0 ≤ w < 1, and x + y + z + w = ​​1.

[0102] According to an embodiment of the present invention, in another aspect, a battery pack 100 is also provided, comprising a plurality of the aforementioned batteries 10.

[0103] In one embodiment, such as Figure 17 As shown, the first shell wall 14 has two second sides 141 arranged opposite each other along its length direction, and two third sides 142 arranged opposite each other along its width direction. The length of the third side 142 is greater than the length of the second side 141. A plurality of batteries 10 are arranged sequentially along the width direction of the first shell wall 14, with adjacent batteries 10 bonded together, satisfying 9≤d×h×V≤119.3. This arrangement, by arranging the plurality of batteries 10 along the extension direction of the short side of the first shell wall 14, allows the large surfaces of adjacent batteries 10 to bond together, thereby restricting the large surfaces of the batteries 10 from deformation due to their interaction. This also constrains the weld lines along the long side of the first shell wall 14, reducing the risk of cracking of the weld lines along the long side of the first shell wall 14. Therefore, by further limiting the values ​​of d×h×V, the structural strength of the explosion-proof valve 2 is further improved, ensuring the predetermined opening pressure of the explosion-proof valve 2, preventing premature or accidental opening of the explosion-proof valve 2, and ensuring the reliability of the explosion-proof valve 2.

[0104] According to an embodiment of the present invention, in another aspect, an electrical device is also provided, including the battery pack 100 described above.

[0105] 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.

[0106] The preparation of the example battery and the comparative battery includes the following steps: (1) Preparation of the positive electrode: The prepared positive electrode active material, conductive agent (e.g., acetylene black), and binder (e.g., 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 foil, dried at room temperature, and then transferred to an oven for further drying. The positive electrode sheet is then obtained by rolling and slitting.

[0107] Specifically, the mass ratio of positive electrode active material: conductive agent: binder satisfies (92~98): (4~1): (4~1).

[0108] (2) Preparation of negative electrode: The negative electrode active material, conductive agent (e.g., acetylene black), thickener (e.g., carboxymethyl cellulose (CMC)), and binder (e.g., styrene-butadiene rubber (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 foil, air-dried at room temperature, and then transferred to an oven for further drying. Finally, the negative electrode sheet is obtained by rolling and slitting.

[0109] Specifically, the ratio of negative electrode active material: conductive agent: thickener: binder satisfies (90~96): (4~2): (2~1): (4~1).

[0110] (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.

[0111] (4) Preparation of the diaphragm: Polyethylene film is selected as the diaphragm.

[0112] (5) Preparation of lithium-ion batteries: The positive electrode, separator, and negative electrode are stacked in sequence and formed into a bare cell by winding or stacking. The bare cell is then placed in a battery casing, which is a prismatic casing. The battery is dried, injected with electrolyte, and then packaged, allowed to stand, formed, and calibrated to obtain a lithium-ion battery.

[0113] In the selection of materials for the battery, this application may also select other materials, not limited to the materials limited by the above preparation method. The positive electrode active material may 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 may be selected from one or more negative electrode active main materials, such as artificial graphite, natural graphite, silicon carbide, silicon oxide, and lithium titanate.

[0114] The conductive agent includes, but is not limited to, one or more combinations of graphite, superconducting carbon, carbon black (such as acetylene black, Ketjen black, Super P, etc.), carbon nanotubes, graphene, and carbon nanofibers.

[0115] 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.

[0116] The solvent can be deionized water, NMP (N-methylpyrrolidone), alcohol, ether, ketone or other types of pyrrolidone, etc.

[0117] 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.).

[0118] 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.).

[0119] The difference between the batteries in each embodiment and the comparative battery lies in the values ​​of d, h, and V. Apart from these, all other characteristics of the batteries are the same, as shown in Table 1.

[0120] The relevant performance of the batteries in the above embodiments and comparative examples was tested, and the test results are recorded in Table 1. The test methods are as follows: Performance 1: Proportion of explosion-proof valve opening in advance Following the battery fabrication method described above, 200 batteries were prepared for each embodiment and comparative example, and stacked with their large side surfaces facing each other. The large side surface is the surface with the largest area on the outer surface of the battery. The terminals of 20 batteries were electrically connected via conductive busbars to form a battery pack. A preload of 3000 N was applied to the large side of the battery pack on the side furthest from the other batteries. All other test conditions remained consistent.

[0121] The battery pack was subjected to 100 charge-discharge cycles at room temperature (20°C). The cycle conditions were as follows: constant current charging at a 4C rate until the battery voltage reached the upper limit voltage; then switching to constant voltage charging until the battery current dropped to 0.05C; allowing it to rest for 30 minutes; and finally discharging at a 1C rate until the lower limit voltage was reached. The upper and lower limit voltages for individual cells need to be adjusted accordingly for different systems: Lithium iron phosphate (LFP) - upper limit voltage 3.65V, lower limit voltage 2.5V; Nickel-cobalt-manganese ternary NCM - upper limit voltage 4.25V, lower limit voltage 2.5V; Lithium manganese iron phosphate (LFMP) - upper limit voltage 4.25V, lower limit voltage 2.5V; Lithium nickel manganese oxide - upper limit voltage 4.8V, lower limit voltage 3.5V.

[0122] Then, according to the requirements of GB / T2423.43, the test object is mounted on the vibration table. The test procedure is carried out according to the provisions of GB / T2423.56. Random and fixed-frequency vibration loads are applied in each direction respectively. The loading sequence should preferably be random z-axis, fixed-frequency z-axis, random y-axis, fixed-frequency y-axis, random x-axis, fixed-frequency x-axis (the direction of the line connecting the front and rear of the battery pack is the x-axis direction, and the other horizontal direction perpendicular to the x-axis direction is the y-axis direction). The vibration frequency, power spectral density (PSD), vibration time, etc. are shown in the table below.

[0123]

[0124] Observe whether the explosion-proof valves of the batteries in the battery pack open prematurely, which is manifested by cracking in the thinned area of ​​the explosion-proof valve or leakage of the battery in the explosion-proof valve area. The premature opening ratio of the explosion-proof valve = (number of batteries with prematurely opened explosion-proof valves / 200) × 100%. If the premature opening ratio of the explosion-proof valves is less than or equal to 2%, it is considered good; if the premature opening ratio of the explosion-proof valves is greater than 2% but less than or equal to 3%, it is considered acceptable; if it is greater than 3%, it is considered unacceptable.

[0125] 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 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 the ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0126] Performance 2: Cover plate weld line cracking ratio Following the battery fabrication method described above, 50 batteries were prepared for each embodiment and comparative example, with all other test conditions remaining consistent. The batteries were charged at a constant current rate of 1 / 3C to the upper limit voltage at room temperature (20°C), then switched to constant voltage charging until the current was less than 0.05C, and allowed to stand for 30 minutes. Heating wires were then evenly wrapped around the surface of each battery, and the batteries were placed in an adiabatic accelerated calorimeter (ARC) for adiabatic thermal stability testing until thermal runaway occurred.

[0127] After the battery thermal runaway ends, observe the weld lines of the battery casing and cover plate. If a break occurs at the weld line, exposing the inside of the casing, it is judged as a crack in the cover plate weld line. The cracking rate of the cover plate weld line is calculated as (number of batteries with cracked cover plate weld lines / 50) × 100%. If the cracking rate of the cover plate weld line is less than or equal to 4%, it is considered good; if the cracking rate is greater than 4% but less than or equal to 8%, it is considered acceptable; if the cracking rate is greater than 8%, it is considered unacceptable.

[0128] For different battery systems, the upper and lower voltage limits for a single cell need to be adjusted accordingly: Lithium iron phosphate (LFP) - upper limit 3.65V, lower limit 2.5V; Nickel-cobalt-manganese ternary NCM - upper limit 4.25V, lower limit 2.5V; Lithium manganese iron phosphate (LFMP) - upper limit 4.25V, lower limit 2.5V; Lithium nickel manganese oxide - upper limit 4.8V, lower limit 3.5V. In this test, the positive electrode active material was selected from LiNi... 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, other positive electrode 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 the ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0129] Table 1:

[0130] As can be seen from Table 1, in Examples 1 to 15, the values ​​of d×h×V are all within the range of 3.8 to 119.3. Therefore, in Examples 1 to 15, there are no unqualified cases in the test of the proportion of premature opening of the explosion-proof valve and the test of the proportion of cracked cover plate weld lines.

[0131] As can be seen from Table 1, in Comparative Example 1 and Comparative Example 3, the values ​​of d×h×V are not within the range of 3.8 to 119.3 and are greater than 119.3, which leads to the failure of the cover plate weld line cracking ratio test for the batteries in Comparative Example 1 and Comparative Example 3.

[0132] As can be seen from Table 1, in Comparative Example 2, the value of d×h×V is not within the range of 3.8 to 119.3 and is less than 3.8, which causes the proportion test of premature opening of the explosion-proof valve of the battery in Comparative Example 2 to fail.

[0133] Furthermore, as shown in Table 1, in Examples 2 and 11 to 15, the tests on the proportion of early opening of the explosion-proof valve and the proportion of cracking of the cover plate weld line all met the test requirements. However, the values ​​of some parameters had some impact on the relevant performance, including: In Example 2, the thickness h mm of the thinning zone is relatively small, which leads to a decrease in the opening pressure of the explosion-proof valve and an increase in the risk of premature opening of the explosion-proof valve.

[0134] In Example 11, the volumetric energy density V Wh / L of the battery is relatively large, which leads to an increase in the heat generated inside the battery during thermal runaway, increasing the risk of the weld lines of the casing and cover being broken, and the proportion of cracked weld lines on the cover is relatively large.

[0135] In Examples 12 and 15, the thickness h mm of the thinning zone is relatively large, resulting in a larger opening pressure of the explosion-proof valve, which increases the risk of the weld lines of the shell and cover being broken, and the proportion of cracked weld lines of the cover is relatively large.

[0136] In Examples 13 and 14, the average pore diameter d mm of the pores is relatively large. Under high temperature, the risk of adjacent pores connecting to form large pores increases, which increases the risk of the weld lines of the shell and cover being broken, and the proportion of cracked weld lines of the cover is relatively large.

[0137] The following is an explanation of the terms used in this application.

[0138] Battery packs can serve as the operating power source for electrical devices, or as the driving power source for electrical devices, replacing or partially replacing fuel or natural gas to provide driving power for vehicles. Electrical devices include: energy storage devices, electric ships, aircraft, laptops, power tools, electric bicycles, electric motorcycles, electric cars, military equipment, aerospace, and many other technological fields.

[0139] A battery pack consists of multiple batteries, which can be connected in series, parallel, or a combination thereof. A combination thereof means that multiple batteries are connected in both series and parallel.

[0140] The battery pack is a cluster-level battery structure formed by multiple batteries connected in series, where the number of batteries in each cluster is strictly configured according to voltage and capacity requirements. Specifically, the battery unit of the battery pack includes multiple batteries, some of which are connected in series to form a cluster that meets the preset power supply voltage requirements, and at least one spare battery among the multiple batteries is bypassed.

[0141] The battery pack may include battery cells and a switching control unit.

[0142] A battery can store chemical energy and controllably convert it into electrical energy. In recyclable batteries, the active materials can be reactivated by charging after discharge, allowing for continued use. A battery includes a casing assembly and battery cells housed within the casing assembly.

[0143] Terminals are used to electrically connect battery cells located inside the housing assembly to external devices (adjacent batteries or other electrical equipment) located outside the housing assembly. The battery can discharge to external devices through the cell output terminals (tabs) and the external device output terminals (terminals), and an external power source can charge the battery through the terminals and tabs. Terminals can be directly electrically connected to the cell tabs or electrically connected to the tabs through metal adapters.

[0144] The electrode post is made of metal materials including but not limited to copper, aluminum, aluminum alloy, and copper-aluminum alloy.

[0145] An explosion-proof valve is a component or part that can be actuated to release internal pressure or temperature when the internal pressure or temperature of a battery cell reaches a predetermined threshold.

[0146] During battery use, explosion-proof valves are mainly used to prevent excessive pressure buildup inside the battery, which could cause deformation or explosion, by allowing gas to escape and reducing the internal pressure of the battery in the event of thermal runaway or other situations.

[0147] The materials used for explosion-proof valves are not limited, including but not limited to aluminum, steel, and alloys. The shapes of explosion-proof valves are not limited, such as square, oblong, elliptical, racetrack-shaped, etc. The types of explosion-proof valves are not limited, such as scored explosion-proof valves, which can be formed by stamping or laser etching.

[0148] 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 battery, characterized in that, include: The housing assembly (1) includes a housing (11) and a cover plate (12), wherein at least one end of the housing (11) is formed with an opening, and the cover plate (12) and the housing (11) are welded to form a first weld mark (13), and the cover plate (12) seals the opening and encloses the housing (11) to form an accommodating space; An explosion-proof valve (2) is provided in the housing assembly (1), which has a first housing wall (14), and the explosion-proof valve (2) is disposed on the first housing wall (14). The explosion-proof valve (2) has a thinning area (21). The battery cell (3) is disposed within the accommodating space; The first solder mark (13) has pores (131) formed in it. The average pore diameter of the pores (131) is d mm. The thickness of the thinning region (21) is h mm. The volumetric energy density of the battery (10) is V Wh / L, which satisfies 3.8≤d×h×V≤119.

3.

2. The battery according to claim 1, characterized in that, On a cross section perpendicular to the penetration direction of the first weld mark, the cross section of the pore (131) has a first major axis (1311) and a first minor axis (1312). The first major axis is the axis with the longest length on the cross section of the pore, and the first minor axis is the axis with the shortest length on the cross section of the pore. The length of the first major axis (1311) is a mm, and the length of the first minor axis (1312) is b mm, satisfying a mm > b mm.

3. The battery according to claim 2, characterized in that, The length a mm of the first major axis (1311) and the length b mm of the first minor axis (1312) satisfy 0.33 ≤ b / a < 1.

4. The battery according to claim 2, characterized in that, The average pore diameter d mm of the pores (131) satisfies 0.2 mm ≤ d mm ≤ 0.9 mm.

5. The battery according to claim 1, characterized in that, Along the penetration direction of the first weld mark (13) and / or the penetration direction of the first weld mark (13), the distance between adjacent pores (131) is c mm, satisfying 0.5 mm ≤ c mm ≤ 200 mm.

6. The battery according to claim 1, characterized in that, The penetration depth of the first solder mark (13) is e mm, satisfying 0.3 mm ≤ e mm ≤ 2 mm; and / or, The weld width of the first solder mark (13) is f mm, which satisfies 0.6 mm ≤ f mm ≤ 3 mm.

7. The battery according to claim 1, characterized in that, The average pore diameter d mm of the pores (131) satisfies 0.2 mm ≤ d mm ≤ 1 mm; and / or, The thickness h mm of the thinning region (21) satisfies 0.04 mm ≤ h mm ≤ 0.3 mm; and / or, The volumetric energy density V Wh / L of the battery (10) satisfies 300Wh / L≤V Wh / L≤460Wh / L.

8. The battery according to any one of claims 1 to 7, characterized in that, The thickness of the cover plate (12) is greater than the wall thickness of the housing (11), and the explosion-proof valve (2) is disposed on the cover plate (12).

9. The battery according to claim 8, characterized in that, The minimum distance between the thinning area (21) and the first solder mark (13) is g mm, which satisfies 2.5 mm ≤ g mm ≤ 52 mm.

10. The battery according to claim 8, characterized in that, The length direction of the thinning zone (21) is parallel to the length direction of the cover plate (12).

11. The battery according to claim 8, characterized in that, The battery (10) also includes a terminal post (4), which is electrically connected to the cell (3). The terminal post (4) is disposed on the cover plate (12). The minimum distance between the terminal post (4) and the thinning area (21) is i mm, which satisfies 50 mm ≤ i mm ≤ 180 mm.

12. The battery according to any one of claims 1 to 7, characterized in that, The first shell wall (14) is located on the shell (11), and the first shell wall (14) is disposed opposite to the cover plate (12).

13. The battery according to claim 12, characterized in that, The battery (10) also includes a terminal post (4), which is electrically connected to the cell (3). The terminal post (4) is disposed on the cover plate (12), and the thickness hmm of the thinning area (21) satisfies 0.04mm≤hmm≤0.25mm.

14. The battery according to claim 12, characterized in that, Along the arrangement direction of the first shell wall (14) and the cover plate (12), the height of the battery (10) is j mm, which satisfies j mm≥120mm and 3.8≤d×h×V≤105.

15. The battery according to claim 12, characterized in that, The battery (10) further includes a terminal post (4), which is electrically connected to the cell (3). There are two terminals (4), which are spaced apart along the length of the cover plate (12). The cover plate (12) has two first sides (121) arranged opposite to each other along its length. The minimum distance between the first side (121) and the terminal post (4) along the length of the cover plate (12) is p. The first shell wall (14) has two second sides (141) arranged opposite to each other along its length. The minimum distance between the second side (141) and the thinning area (21) along the length of the first shell wall (14) is q. p < q.

16. The battery according to any one of claims 1 to 7, characterized in that, The thinning area (21) has a groove (22) formed on the side facing the battery cell (3) or on the side away from the battery cell (3).

17. The battery according to claim 16, characterized in that, The groove (22) is formed on the side of the explosion-proof valve (2) facing the battery cell (3), and the thickness h mm of the thinning area (21) satisfies 0.04 mm ≤ h mm ≤ 0.22 mm.

18. The battery according to claim 16, characterized in that, The groove (22) is formed on the side of the explosion-proof valve (2) away from the battery cell (3), and the depth of the groove (22) is k mm, which satisfies k mm ≥ 0.2 mm.

19. The battery according to any one of claims 1 to 7, characterized in that, The thinning zone (21) has an incompletely closed annular structure to form a first end (211) and a second end (212) at both ends along its extension path, the first end (211) and the second end (212) are spaced apart, and a connecting section (23) is formed between the first end (211) and the second end (212).

20. The battery according to claim 19, characterized in that, The first shell wall (14) has two third sides (142) arranged opposite to each other along its width direction. Along the width direction of the first shell wall (14), the connecting section (23) and the third sides (142) are arranged opposite to each other and spaced apart.

21. The battery according to any one of claims 1 to 7, characterized in that, The first shell wall (14) has a through hole (143) that extends through it along its thickness direction. The first shell wall (14) protrudes in a direction away from the battery cell (3) to form a protrusion (144). The protrusion (144) surrounds the through hole (143). The protrusion (144) has an inner circumferential surface (1441). The inner circumferential surface (1441) surrounds the through hole (143). The explosion-proof valve (2) covers the through hole (143) and is fixedly connected to the protrusion (144).

22. The battery according to claim 21, characterized in that, The protrusion (144) facing the battery cell (3) has a receiving groove (1442) formed around the through hole (143), and at least a portion of the explosion-proof valve (2) is disposed in the receiving groove (1442).

23. The battery according to claim 21, characterized in that, In the direction perpendicular to the extension path of the thinning region (21), the distance between the thinning region (21) and the inner circumferential surface (1441) is n mm, satisfying 0.1 mm ≤ n mm ≤ 2 mm.

24. The battery according to any one of claims 1 to 7, characterized in that, The first shell wall (14) has a reinforcing part (145) formed on the outer periphery of the explosion-proof valve (2), and the reinforcing part (145) protrudes toward or away from the battery cell (3).

25. The battery according to any one of claims 1 to 7, characterized in that, The explosion-proof valve (2) includes an opening portion (24) enclosed by the thinning area (21). The opening portion (24) forms a first surface (241) on the side away from the battery cell (3), and the first shell wall (14) forms a second surface (146) on the side away from the battery cell (3). The first surface (241) is closer to the battery cell (3) than the second surface (146). Along the thickness direction of the first shell wall (14), the distance between the first surface and the second surface is t mm, which satisfies 0.4 mm ≤ t mm ≤ 2.85 mm.

26. The battery according to any one of claims 1 to 7, characterized in that, The explosion-proof valve (2) includes an opening portion (24) formed by the thinning zone (21). On the projection plane perpendicular to the thickness direction of the first shell wall (14), the orthographic projection area of ​​the first shell wall (14) is S1 mm. 2 The projected area of ​​the opening portion (24) is S2 mm. 2 The condition 0.005≤S2 / S1≤0.3 is met.

27. The battery according to any one of claims 1 to 7, characterized in that, The cell (3) comprises ternary materials, and the battery (10) has a capacity of not less than 50Ah and satisfies 3.8≤d×h×V≤95.

28. A battery pack, characterized in that, The battery (10) includes any one of claims 1 to 27.

29. The battery pack according to claim 28, characterized in that, The first shell wall (14) has two second sides (141) arranged opposite each other along its length direction, and two third sides (142) arranged opposite each other along its width direction. The length of the third side (142) is greater than the length of the second side (141). A plurality of batteries (10) are arranged sequentially along the width direction of the first shell wall (14), and adjacent batteries (10) are attached together, satisfying 9≤d×h×V≤119.

3.

30. An electrical device, characterized in that, Includes the battery pack (100) as described in claim 28 or 29.

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