Shell structure, battery and battery pack

Abstract

The invention relates to the technical field of new energy, and discloses a shell structure, a battery and a battery pack. A pressure release valve is arranged on the first wall surface of the shell structure, and the bursting pressure of the pressure release valve is a; the pressure release valve comprises a weak part, and the residual thickness ratio of the weak part is b; the ratio of the mass of the Ti element of the shell structure to the total mass of all the elements of the shell structure is c; wherein c is greater than or equal to 60%; and c * b * a is greater than or equal to 1.5 and less than or equal to 24. According to the shell structure provided by the invention, the light weight of the shell structure is realized by comprehensively controlling the relationship among a, b and c, so that the energy density of the battery is improved; and meanwhile, when the battery is in thermal runaway, the pressure release valve can be opened in time, internal heat is effectively discharged, and detonation of the shell is avoided, so that light weight and safety are both considered. When the formula value of c.b.a is lower than the lower limit, light weight of the shell structure is not facilitated, and when the formula value of c.b.a is higher than the upper limit, the opening pressure of the pressure release valve is too large, and heat cannot be discharged in time.

Description

[0001] This application is a divisional application of the invention entitled "Housing Structure and Battery and Battery Pack", the original application was filed on June 9, 2025, and the application number is 2025107613404. Technical Field

[0002] This invention relates to the field of new energy technology, specifically to a housing structure, a battery, and a battery pack. Background Technology

[0003] In related technologies, battery casings are often made of steel to meet the requirements of high strength and high safety performance. However, steel casings have a high density, which can easily increase the overall weight of the battery pack, thus affecting the vehicle's range and performance. In addition, in the event of battery thermal runaway, the high-strength casing cannot effectively dissipate heat, which can easily lead to explosions or other safety accidents. Summary of the Invention

[0004] In view of this, the present invention provides a housing structure, a battery, and a battery pack to solve the problem of how to balance lightweight design with the need for smooth venting in the event of thermal runaway.

[0005] In a first aspect, the present invention provides a shell structure comprising Ti element; A pressure relief valve is provided on the first wall of the shell structure, and the burst pressure of the pressure relief valve is a MPa; the shell structure is cylindrical. The pressure relief valve includes a weak section with a residual thickness of b1 and a thickness of b2 on the first wall surface. The ratio of the residual thickness of the weak section to the thickness of b is b, where b = b1 / b2. The mass percentage of Ti in the shell structure relative to the total mass of all elements in the shell structure is c%; where 92.36% ≤ c% ≤ 99.99%; And it satisfies: 3.05≤c·b·a≤24.

[0006] Beneficial Effects: The casing structure provided by the embodiments of the present invention achieves lightweighting of the casing structure by comprehensively controlling the relationship between a, b, and c, thereby improving the energy density of the battery. Simultaneously, it ensures that the pressure relief valve can open promptly in the event of battery thermal runaway, effectively dissipating internal heat and preventing casing explosion, thus balancing lightweighting and safety. When the formula value of c·b·a is below the lower limit, the battery is prone to abnormal explosion during normal charging and discharging; this also hinders the lightweighting of the casing structure and easily affects the battery's energy density. Conversely, when the formula value is above the upper limit, the pressure relief valve opening pressure is too high, hindering its opening and preventing timely heat dissipation, resulting in severe heat accumulation inside the battery and causing casing explosion, posing a safety hazard.

[0007] Secondly, the present invention also provides a battery comprising: The battery cell; and a housing structure as described above, wherein a cavity is formed inside the housing structure, the cavity being adapted to accommodate the battery cell.

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

[0009] Thirdly, the present invention also provides a battery pack, comprising: a housing and a plurality of batteries as described above, the housing comprising a bottom plate and a plurality of side plates, the batteries being fixed to the bottom plate of the housing.

[0010] Since the battery pack includes a housing structure and has the same effect as the housing structure, it will not be described in detail 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 shell structure of the present invention; Figure 2 This is a top view of the shell structure of the present invention; Figure 3 This is a top view of another shell structure of the present invention; Figure 4 for Figure 2 A partial schematic diagram of section AA; Figure 5 for Figure 4 Enlarged view of point B in the middle; Figure 6 for Figure 4 Another magnified view of point B in the middle; Figure 7 for Figure 4 Another magnified view of point B in the middle; Figure 8 for Figure 4 Another magnified view of point B in the middle; Figure 9 This is a partial enlarged view of the first wall surface of the present invention; Figure 10 This is another enlarged view of the first wall surface of the present invention; Figure 11 This is another enlarged view of a portion of the first wall surface of the present invention; Figure 12 This is another partially enlarged view of the first wall surface of the present invention; Figure 13 This is a top view of yet another shell structure of the present invention; Figure 14 This is an exploded view of the battery of the present invention; Figure 15 This is a schematic diagram of the groove of the present invention.

[0013] Explanation of reference numerals in the attached figures: 1. Shell structure; 10. Shell body; 11. First wall surface; 12. Compacted part; 13. Recessed part; 14. Cover plate; 15. Second wall surface; 2. Pressure relief valve; 21. Weak part; 22. Valve plate part; 23. First groove part; 24. Second groove part; 241. Second inner groove part; 242. Second outer groove part; 3. Terminal post; 4. Battery cell; 41. Battery cell body; 42. Positive electrode tab; 43. Negative electrode tab; 51. Opening; 52. Bottom wall; 53. Side wall; 54. Arc-shaped transition section. 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] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0016] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0017] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0018] In related technologies, battery casings are often made of steel to meet the requirements of high strength and high safety performance. However, steel casings have a high density, which can easily increase the overall weight of the battery pack, thus affecting the vehicle's range and performance.

[0019] Ti (TiO2) has a significantly lower density than steel, allowing Ti components to be lighter than steel components while maintaining the same strength requirements. Therefore, adding a certain proportion of Ti to the casing can reduce its weight, achieving lightweighting and thus increasing the battery's energy density. However, due to Ti's high strength, in the event of battery thermal runaway, the heat and gas inside the casing need to break through weak points to release the heat. If the weak points are too strong, the heat and gas inside the casing may not be sufficient to break them open, and as heat continues to accumulate, a sudden explosion could easily occur, causing a safety hazard. Therefore, how to reduce casing weight, achieve lightweighting, and increase battery energy density while ensuring smooth venting of the high-strength casing during battery thermal runaway has become a pressing issue.

[0020] To better understand the technical solution of this application, the following explanation is provided first: The battery in this application is a secondary battery, also known as a rechargeable battery or storage battery, which refers to a battery that can be used again after being discharged by recharging to activate the active materials.

[0021] Typically, a secondary battery consists of a battery cell, an electrolyte, and a casing. The battery cell includes a positive electrode, a negative electrode, and a separator. The battery cell and electrolyte are assembled inside the casing. During charging and discharging, active ions (such as lithium ions) move back and forth between the positive and negative electrodes, inserting and releasing. The separator, located between the positive and negative electrodes, primarily prevents short circuits while allowing active ions to pass through. The electrolyte, situated between the positive and negative electrodes, mainly serves to conduct active ions.

[0022] As an example, the preparation process of a secondary battery is as follows: the positive electrode, separator, and negative electrode are stacked in sequence, with the separator acting as a separator between the positive and negative electrodes. Then, the electrodes are wound or stacked to obtain a cell. The cell is placed in a casing, dried, and then injected with electrolyte. After vacuum sealing, settling, formation, and shaping, a secondary battery is obtained.

[0023] The positive electrode, negative electrode, electrolyte, and separator are described in turn below: [Positive electrode tablets] A positive electrode typically includes a positive current collector and a positive electrode film layer disposed on at least one side of the positive current collector. The positive electrode film layer includes a positive electrode active material, which can be any existing publicly disclosed positive electrode active material or a positive electrode active material optimized based on existing materials.

[0024] This application does not impose any particular restrictions on the type of positive electrode active material for the positive electrode sheet. As an example, the positive electrode active material in this application includes lithium-containing transition metal oxides (e.g., LiCoO2), phosphides (e.g., LiFePO4), or lithium intercalation compounds (e.g., positive electrode materials for binary lithium batteries such as lithium cobalt oxide and lithium nickel oxide, or positive electrode materials for ternary lithium batteries such as lithium nickel cobalt manganese oxide and lithium nickel cobalt aluminum oxide).

[0025] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive electrode active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, rolling, cutting and other processes.

[0026] In this application, the binder is used to improve the adhesion between positive electrode active material particles and the adhesion between the positive electrode active material and the current collector. This application does not impose any particular limitation on the type of binder for the positive electrode sheet; the binder can be any conventional choice in the battery industry. Specifically, the binder can be at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl alcohol (PVA), styrene-butadiene rubber (SBR), polyacrylonitrile (PAN), polyimide (PI), polyacrylic acid (PAA), polyacrylate, polyolefin, sodium carboxymethyl cellulose (CMC), or sodium alginate.

[0027] This application does not impose any particular restrictions on the positive electrode current collector, as long as it is conductive and will not cause adverse chemical changes in the battery, and can be made of, for example: stainless steel, aluminum, nickel, titanium, sintered carbon; or aluminum or stainless steel that has been surface treated with one of carbon, nickel, titanium, silver, etc.

[0028] [Negative electrode plate] The negative electrode includes a negative electrode current collector and a negative electrode active material layer disposed on at least one side of the negative electrode current collector. The negative electrode active material layer comprises a silicon-based material. This application does not specifically limit the type of silicon-based material; the silicon-based material can be a silicon-carbon material and / or a silicon-oxygen material. As an example, the silicon-based material can be one or more of silicon-carbon composite negative electrode materials, silicon suboxide negative electrode materials, modified silicon suboxide negative electrode materials, and nano-silicon materials. The negative electrode active material in the negative electrode active material layer may also optionally include one or more of artificial graphite, natural graphite, and hard carbon.

[0029] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, rolling, cutting and other processes.

[0030] This application does not specifically limit the type of negative electrode conductive agent. In some embodiments, as an example, the negative electrode conductive agent can be one or more of conventional negative electrode conductive agents such as acetylene black and carbon nanotubes. This application does not specifically limit the type of negative electrode binder. In some embodiments, as an example, the binder can be one or more of conventional negative electrode binders such as styrene-butadiene rubber latex (SBR), polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), and sodium carboxymethyl cellulose (CMC). In this application, the binder is preferably PAA, SBR, and CMC, and the mass ratio of PAA, SBR, and CMC can be (34.38-74.29):(20-59.38):(5-7.14).

[0031] This application does not impose specific limitations on the type of negative electrode current collector. In some embodiments, as an example, the negative electrode current collector can be one of the conventional negative electrode current collectors such as copper foil.

[0032] Electrolyte The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. As an example, the electrolyte in this application can be any electrolyte suitable for electrochemical energy storage devices in the art. The electrolyte includes an electrolyte and a solvent; the electrolyte typically includes a lithium salt, and additives may also be added to the electrolyte.

[0033] Specifically, the lithium salt includes at least one selected from lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP). The concentration of the electrolyte in the electrolyte solution can be 0.5–5 mol / L.

[0034] Specifically, the solvent includes at least one of ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butyl carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0035] In some implementations, as an example, the additive may be a conventional electrolyte additive such as fluoroethylene carbonate (FEC), chloroethylene carbonate (CEC), or vinylene carbonate (VC).

[0036] [Septum] In some embodiments, the secondary battery also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.

[0037] In some embodiments, as an example, the diaphragm can be one of PP, PE, or PP / PF; the diaphragm can also be a structure in which a coating is formed on the surface of the base film, wherein the base film coating can be one of PP, PE, or PP / PF, and the coating can be an inorganic coating and / or an organic coating. The inorganic coating can be selected from alumina ceramic layers, osmium silicate, etc., and the organic coating can be selected from PVDF, etc.

[0038] The following is combined Figures 1 to 14 The following describes embodiments of the present invention.

[0039] According to an embodiment of the present invention, in one aspect, a shell structure 1 is provided, the shell structure 1 comprising Ti element; A pressure relief valve 2 is provided on the first wall surface 11 of the shell structure 1, and the burst pressure of the pressure relief valve 2 is a MPa; The pressure relief valve 2 includes a weak part 21, the remaining thickness of the weak part 21 is b1, the thickness of the first wall surface 11 is b2, and the ratio of the remaining thickness of the weak part 21 is b, where b = b1 / b2. The mass of Ti in the shell structure accounts for c% of the total mass of all elements in the shell structure; where c% ≥ 60%; And it satisfies: 1.5≤c·b·a≤24.

[0040] In this embodiment, the housing structure 1 is applied to a battery. Optionally, the battery can be a cylindrical battery or a prism battery (not shown in the figure). The battery can be manufactured in a wound form or a stacked form.

[0041] The pressure relief valve 2 is used to release the gas and heat inside the battery when thermal runaway occurs.

[0042] The housing structure 1 in this embodiment contains Ti, which helps to achieve a lightweight design and thus improve the energy density of the battery. However, due to the high strength of Ti, the larger the c, the higher the overall strength of the housing structure 1, which increases the difficulty of heat dissipation during thermal runaway. This leads to an increase in the burst pressure 'a' of the pressure relief valve 2, preventing the heat accumulated inside the battery from being smoothly discharged through the pressure relief valve 2, which can easily cause battery explosion.

[0043] In this embodiment, the content of c% is greater than or equal to 60%. As a further optional option, the shell structure can be made of pure titanium or Ti alloy, such as titanium-aluminum alloy, titanium-aluminum-zirconium alloy, titanium-molybdenum alloy, etc.

[0044] When the shell structure is made of pure titanium, it means that the c% content of the shell structure is greater than or equal to 99.95%.

[0045] The housing structure 1 provided in the embodiments of the present invention achieves lightweighting by comprehensively controlling the relationship between a, b, and c, thereby improving the energy density of the battery. Simultaneously, it ensures that the pressure relief valve 2 can open promptly in the event of battery thermal runaway, effectively dissipating internal heat and preventing casing explosion, thus balancing lightweighting and safety. When the formula value of c·b·a is below the lower limit, the battery is prone to abnormal explosion during normal charging and discharging; this also hinders the lightweighting of the housing structure and easily affects the battery's energy density. Conversely, when the formula value is above the upper limit, the pressure relief valve opening pressure is too high, hindering its opening and preventing timely heat dissipation. This leads to severe heat accumulation inside the battery, causing casing explosion and posing a safety hazard.

[0046] By controlling the relationship between the three components, the housing structure 1 effectively reduces the overall weight while maintaining high strength, achieving lightweighting of the housing structure and improving the energy density of the battery. At the same time, it ensures that the pressure relief valve 2 responds quickly and smoothly dissipates heat in the event of thermal runaway, significantly improving the safety performance of the battery and the driving range of the vehicle.

[0047] For example, in this embodiment, the value of c·b·a can be 1.5 or 2.17 or 2.26 or 2.36 or 2.42 or 2.67 or 2.85 or 3 or 3.12 or 3.54 or 4.18 or 4.35 or 5.3 or 6.4 or 8.8 or 9.5 or 10 or 12.3 or 13.8 or 15.2 or 16.9 or 18.7 or 20 or 21.2 or 23.7 or 24, etc., or it can be a range formed by any two of the above values.

[0048] In some embodiments, aMPa satisfies: 1.3MPa≤aMPa≤2.6MPa; And / or, b satisfies: 0.01 ≤ b ≤ 0.1; And / or, c% satisfies: 60%≤c%≤99.99%.

[0049] This embodiment further controls the c% content within the range of 60% ≤ c% ≤ 99.99%, thereby avoiding excessively high shell strength due to an excessively high Ti content. This ensures that the pressure relief valve 2 can open promptly in the event of thermal runaway, effectively dissipating heat and preventing battery explosion, achieving a balance between lightweight design and safety. Simultaneously, it ensures that the shell structure 1 has sufficient strength to prevent safety hazards caused by insufficient strength during normal use, while maintaining the lightweight design of the shell structure 1, increasing the battery's energy density, and preserving the battery's lightweight advantage.

[0050] To ensure timely pressure relief under high-temperature conditions, b is further controlled within the range of 0.01 ≤ b ≤ 0.1. This allows gas to quickly open the weak point 21 of the pressure relief valve 2 in the event of battery thermal runaway, enabling the timely release of hot gas. Simultaneously, it prevents the weak point 21 from abnormally opening under normal battery operating conditions. By precisely controlling the residual thickness ratio b of the weak point 21, it ensures rapid response at high temperatures and stability under normal conditions.

[0051] Additionally, to ensure timely pressure relief under high-temperature conditions, the burst pressure a of the pressure relief valve 2 is appropriately reduced to enable it to respond promptly in high-temperature environments, ensuring rapid heat dissipation and preventing casing deflagration. At the same time, the burst pressure a of the pressure relief valve 2 should not be too low to avoid accidental triggering under normal operating conditions, which could affect battery safety and ensure the integrity of the weak point 21 under normal operating conditions.

[0052] For example, in this embodiment, aMPa can be 1.3MPa, 1.5MPa, 1.8MPa, 1.92MPa, 2MPa, 2.15MPa, 2.23MPa, 2.4MPa, or 2.6MPa, or it can be any range formed by any two of the above values.

[0053] For example, in this embodiment, the value of b can be 0.01, 0.03, 0.04, 0.05, 0.07, or 0.1, or it can be any range formed by any two of the above values.

[0054] For example, in this embodiment, the value of c% can be 60% or 70% or 75% or 80% or 85% or 88% or 92% or 99.99%, or it can be a range formed by any two of the above values.

[0055] Referring to Table 1 below, the provided battery was subjected to weight loss rate and cycle performance tests through several embodiments and comparative tests to verify its qualification.

[0056] Table 1

[0057] Regarding the table above, the following explanation is provided: Performance 1: Weight Loss Rate Test. Test Method: Use a planar or rod-shaped heating device, with its surface covered by ceramic, metal, or insulating layers. Place the heating surface of the device in direct contact with the surface of the battery cell. Start the heating device within 24 hours, heating the triggering object at its maximum power. A temperature sensor is placed at the battery pressure relief valve port / large side of the battery. Calculate the mass before and after thermal runaway, where the mass of the battery cell before thermal runaway is m1, and the mass of the battery cell after thermal runaway is m2. Obtain the value of (m1-m2) / m1. If this value is less than 40%, it is unacceptable, indicating that the material inside the casing has not been ejected, and the internal temperature of the casing is too high. If this value is greater than or equal to 40%, it is acceptable, and heat can be smoothly discharged through the pressure relief valve, preventing excessive heat inside the battery. The thermal runaway triggering conditions are: a) The triggering object experiences a voltage drop, and the drop exceeds 25% of the initial voltage; b) The temperature at the monitoring point reaches the manufacturer's specified maximum operating temperature; c) The temperature rise rate at the monitoring point, dT / dt, is ≥1℃ / s and lasts for more than 3 seconds. Thermal runaway is determined to have occurred when either a) and c) or b) and c) occur.

[0058] The conclusions of the weight loss rate test in the table above include the following: whether the pressure relief valve can open normally during thermal runaway; and the specific numerical range of the weight loss rate.

[0059] Performance 2: Cyclic Performance Test. Test Method: The lithium-ion batteries prepared in the examples and comparative examples were subjected to a cycle test at 25°C according to the following procedure: 1) Charge at a constant current rate of 1C to the upper limit voltage, and then charge at a constant voltage until the current drops to 0.05C; 2) Let it stand for 20 minutes; 3) Discharge at a 1C rate to the lower limit voltage; 4) Let it stand for 20 minutes. Perform a cyclic test following steps 1)-4), cycling 50 times. Observe whether the pressure relief valve flies out during the cycle. If the pressure relief valve flies out, it indicates that the battery is abnormally opened under working conditions and is unqualified.

[0060] Among them, LiNi 0.9 Co 0.05 Mn 0.05 02 Upper limit voltage 4.25V, lower limit voltage 2.5V; Lithium iron phosphate upper limit voltage 3.65V, lower limit voltage 2.5V.

[0061] The conclusions of the cycle performance test in the table above include the following: whether the battery is abnormally activated while in operation.

[0062] It should be noted that the battery cell is formed by stacking a positive electrode plate, a negative electrode plate, and a separator placed between the two to form the battery cell body 41.

[0063] Positive electrode sheet: includes positive electrode current collector and positive electrode active material. The positive electrode current collector can be made of metal materials such as aluminum foil, nickel foil, and stainless steel, or a composite foil formed by combining metal and insulating materials. The positive electrode active material includes positive electrode active material, conductive agent, binder, etc. The positive electrode active material includes one or more of lithium-containing positive electrode active materials such as lithium iron phosphate, ternary materials containing nickel, cobalt and manganese, and lithium manganese iron phosphate. Negative electrode sheet: includes negative electrode current collector and negative electrode active material. The negative electrode current collector can be made of metal materials such as copper foil, aluminum foil, and stainless steel, or it can be a composite foil material formed by combining metal and insulating materials. The negative electrode active material includes negative electrode active main material, conductive agent, binder, etc. The negative electrode active main material includes one or more of the following: artificial graphite, natural graphite, silicon carbide, silicon oxide, lithium titanate, etc.

[0064] The battery manufacturing process includes the following steps: (1) Preparation of the positive electrode: The prepared positive electrode active material, conductive agent acetylene black, and binder PVDF were mixed, and solvent NMP was added. The mixture was stirred under vacuum until the system was homogeneous to obtain a positive electrode slurry. The positive electrode slurry was 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 was cold-pressed and slit to obtain the positive electrode sheet. Specifically, the mass ratio of positive electrode material: conductive agent: binder satisfies 96:2:2. The cathode materials in Examples 1-12 and Comparative Examples 1-3 were selected from LiNi. 0.9 Co 0.05 Mn 0.05 02; Examples 14 and 15 and Comparative Examples 4-5, the cathode material was selected from lithium iron phosphate.

[0065] (2) Preparation of negative electrode: The negative electrode active material graphite, 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 homogeneous to obtain a negative electrode slurry. This slurry is then uniformly coated onto both surfaces of the negative electrode current collector copper foil. After air-drying at room temperature, it is transferred to an oven for further drying. Finally, it is cold-pressed and slit to obtain the negative electrode sheet. The ratio of negative electrode graphite: conductive agent: thickener: binder is 96:1.5:1.5:1. (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.

[0066] (4) Preparation of the diaphragm: Polyethylene film is selected as the diaphragm.

[0067] (5) Preparation of lithium-ion batteries: The positive electrode, separator, and negative electrode are prepared in sequence through a stacking process, with the separator positioned between the positive and negative electrodes to act as a separator. After the battery cell is prepared, it is installed in the casing, the battery cover is welded, and the battery undergoes processes such as electrolyte injection, formation, and capacity setting.

[0068] It should be noted that the embodiments listed above are only some possible implementations in the battery manufacturing process, and are not an exhaustive list of all implementations. Those skilled in the art will understand that battery manufacturing is not limited to the selection of positive and negative electrode materials, electrolyte formulation, separator selection, etc. listed above.

[0069] Regarding the test results, referring to Table 1 above, the explanation is as follows: In Examples 1-12, the value of c·b·a satisfies: 1.5 ≤ c·b·a ≤ 24. Performance Test 1 shows that during thermal runaway, the pressure relief valve can open normally, the weight loss rate is greater than or equal to 40%, and surface heat can be smoothly discharged through the pressure relief valve, preventing excessive internal heat in the battery and meeting the performance requirements. Performance Test 2 shows that there is no abnormal opening during battery operation, meeting the performance requirements.

[0070] In Comparative Example 1, the value of c·b·a is greater than the upper limit of the formula value. According to Performance Test 1, during thermal runaway, the pressure relief valve cannot open normally, and the weight loss rate is less than 40%, indicating that the material inside the shell has not been ejected and the temperature inside the shell is too high, which cannot meet the performance requirements.

[0071] In Comparative Example 2, the value of c·b·a is less than the lower limit of the formula value. According to Performance Test 2, there is abnormal opening under battery operation, which cannot meet the performance requirements.

[0072] In Comparative Example 3, the value of c·b·a is greater than the upper limit of the formula. According to Performance Test 1, during thermal runaway, the pressure relief valve cannot open normally, and the weight loss rate is less than 40%, indicating that the material inside the shell has not been ejected and the temperature inside the shell is too high, which cannot meet the performance requirements.

[0073] The comparison between Comparative Examples 1-3 and Examples 1-12 above shows that when the formula value does not meet the range, there is a risk of unqualified weight loss rate or abnormal explosion under normal working conditions. Consequently, when the formula value does not meet the range, the performance requirements cannot be met.

[0074] In Examples 13-15, the value of c·b·a satisfies: 1.5 ≤ c·b·a ≤ 24. Performance Test 1 shows that during thermal runaway, the pressure relief valve can open normally, the weight loss rate is greater than or equal to 40%, and surface heat can be smoothly discharged through the pressure relief valve, preventing excessive internal heat in the battery and meeting the performance requirements. Performance Test 2 shows that there is no abnormal opening during battery operation, meeting the performance requirements.

[0075] In Comparative Example 3, the value of c·b·a is greater than the upper limit of the formula. According to Performance Test 1, during thermal runaway, the pressure relief valve cannot open normally, and the weight loss rate is less than 40%, indicating that the material inside the shell has not been ejected and the temperature inside the shell is too high, which cannot meet the performance requirements.

[0076] In Comparative Example 4, the value of c·b·a is less than the lower limit of the formula value. According to Performance Test 1, during thermal runaway, the pressure relief valve can open normally, the weight loss rate is greater than or equal to 40%, and the surface heat can be smoothly discharged through the pressure relief valve to avoid excessive heat inside the battery and meet the performance requirements.

[0077] Based on the comparison of Comparative Examples 3-4 and Examples 13-15 above, it can be seen that when the formula value does not meet the range, there is a risk of unqualified weight loss rate or abnormal explosion under normal working conditions. Consequently, when the formula value does not meet the range, the performance requirements cannot be met.

[0078] In some embodiments, a groove is partially formed on the first wall surface 11, and the groove forms a weak part 21, where b satisfies: 0.02≤b≤0.08.

[0079] In this embodiment, the groove on the first wall surface 11 can be achieved by laser etching or stamping. Since the groove is integrally formed on the first wall surface 11 of the shell structure, compared with the case of setting an independent pressure relief valve, the integrally formed groove is more difficult to burst open as a pressure relief valve. In order to ensure timely pressure relief under high temperature conditions, the residual thickness ratio b of the weak part 21 is controlled to be smaller, so that when the battery thermal runaway occurs, the gas can quickly open the weak part 21 of the pressure relief valve 2 so that the hot gas can be discharged in time; at the same time, the residual thickness ratio b of the weak part 21 cannot be controlled too small to avoid the weak part 21 from opening abnormally under normal battery operating conditions. By precisely controlling the residual thickness ratio b of the weak part 21, it is ensured that it responds quickly at high temperatures and remains stable under normal conditions.

[0080] The internal structure of the casing forms a cavity suitable for accommodating the battery cell; as an optional implementation, it is combined with... Figure 7 As shown, the opening of the groove partially formed on the first wall surface 11 faces the cavity. Alternatively, in combination with... Figure 6 As shown, the groove opening partially formed on the first wall surface 11 is positioned away from the cavity. Alternatively, in combination with... Figure 8 As shown, the first wall surface 11 has grooves on both sides facing the cavity and away from the cavity.

[0081] In some embodiments, combined with Figure 15 As shown, the groove has an opening 51 and a bottom wall 52, and the width of the opening 51 is greater than the width of the bottom wall 52.

[0082] The width of the opening 51 is greater than the width of the bottom wall 52, which allows heat to be concentrated more on the bottom wall 52, that is, in a smaller area. This makes it easier for the pressure relief valve to open and release the heat. It also makes it easier for the pressure relief valve to be formed.

[0083] In some embodiments, combined with Figure 15 As shown, the width of the groove gradually decreases along the direction from the opening 51 toward the bottom wall 52; the ratio of the width of the groove to the size of the first wall 11 along the width direction of the groove ranges from 0.2 to 0.55.

[0084] Along the direction from the opening 51 toward the bottom wall 52, the width of the groove gradually decreases, thereby forming a guiding effect, which is more conducive to the bursting of the pressure relief valve.

[0085] In some embodiments, combined with Figure 15 As shown, the groove also includes a sidewall 53, which is located between the opening 51 and the bottom wall 52, and the sidewall 53 and the bottom wall 52 form an arc-shaped transition portion 54.

[0086] By forming an arc-shaped transition section 54 between the side wall 53 and the bottom wall 52, stress concentration at the connection point between the side wall 53 and the bottom wall 52 can be avoided, preventing deformation of the groove and thus avoiding affecting the blasting.

[0087] In some embodiments, combined with Figure 2 As shown, the pressure relief valve 2 includes a valve plate portion 22, and a weak portion 21 surrounds the valve plate portion 22 to form a closed ring, where b satisfies: 0.025≤b≤0.08; Or, combine Figure 3 As shown, the pressure relief valve 2 also includes a compaction part 12, and a weak part 21 is arranged around the outer periphery of the valve plate part 22 to form a non-closed annulus. The compaction part 12 is formed in the annulus and in the area where the weak part 21 is not provided; b satisfies: 0.02≤b≤0.07.

[0088] When the weak part 21 forms a closed ring around the valve plate part 22, the valve plate part 22 is subjected to uniform force, ensuring rapid opening during pressure relief. By reasonably selecting the range of the residual thickness ratio b of the weak part 21, both pressure relief efficiency and false triggering are ensured, thereby improving the overall safety performance of the battery.

[0089] When a non-closed ring is formed, the compacted portion 12 can serve as a connecting structure when the pressure relief valve 2 bursts, keeping the valve plate portion 22 connected to other parts of the first wall surface 11, preventing fragments from scattering during pressure relief, and further ensuring battery safety. By reasonably selecting the range of the residual thickness ratio b of the weak portion 21, efficient pressure relief is achieved while preventing the compacted portion 12 from being torn during pressure relief, thus improving the overall safety performance of the battery.

[0090] In some embodiments, combined with Figure 9 or Figure 10 or Figure 11 or Figure 12 As shown, the shell structure is formed with a first groove 23, and a second groove 24 is formed inside the first groove 23, where b satisfies: 0.015≤b≤0.08.

[0091] By forming a first groove 23 in the shell structure and further forming a second groove 24 within the first groove 23, the first groove 23 is used to enhance the local strength of the shell structure, reduce stress concentration, and prevent the deformation of the shell structure from affecting the second groove 24. This makes the second groove 24 more stable, ensures that the second groove 24 can respond accurately at high temperatures, further optimizes the pressure relief effect, and improves the safety and reliability of the overall structure.

[0092] In this embodiment, the second groove 24 is the specific location of the weak part 21. Since the second groove 24 has higher stability, the residual thickness ratio b of the weak part 21 is more precise, and the mass ratio c of Ti in the shell structure can be appropriately increased.

[0093] In some embodiments, combined with Figure 10 As shown, a cavity suitable for accommodating the battery cell is formed inside the housing structure; the second groove portion 24 includes a second inner groove portion 241 with an opening facing the cavity.

[0094] In some embodiments, combined with Figure 9 As shown, a cavity suitable for accommodating the battery cell is formed inside the housing structure; the second groove portion 24 includes a second outer groove portion 242 with an opening opposite to the cavity.

[0095] In some embodiments, combined with Figure 11 or Figure 12 As shown, a cavity suitable for accommodating the battery cell is formed inside the housing structure; the second groove portion 24 includes a second inner groove portion 241 with an opening facing the cavity and a second outer groove portion 242 with an opening away from the cavity; the second inner groove portion 241 and the second outer groove portion 242 are disposed opposite to each other; b satisfies: 0.025≤b≤0.075.

[0096] When the second groove portion 24 includes a second inner groove portion 241 with its opening facing the cavity and a second outer groove portion 242 with its opening facing away from the cavity, the two are arranged opposite to each other. This makes it easier for the pressure relief valve 2 to open in the event of battery thermal runaway, allowing for timely discharge of internal heat and effectively preventing excessive internal pressure in the battery, thus avoiding the risk of explosion. Therefore, it is necessary to strictly control the residual thickness ratio b of the weak part 21 to prevent it from rupturing prematurely under high temperature and pressure, ensuring that the pressure relief valve 2 can reliably start at critical moments.

[0097] In some embodiments, the area enclosed by the pressure relief valve 2 is S1, and the area of ​​the first wall 11 is S2, satisfying: 0.03≤S1 / S2≤0.06.

[0098] By increasing the ratio of S1 / S2, the opening area of ​​the pressure relief valve 2 can be effectively adjusted, increasing the opening space during battery thermal runaway. This allows for more complete release of heat and gas from the casing during thermal runaway, thereby improving pressure relief efficiency. However, increasing the opening area of ​​the pressure relief valve 2 makes it more difficult to open. Therefore, it is necessary to further control the value range of the formula c·b·a to ensure that the pressure relief valve 2 can still open smoothly under high temperature and high pressure conditions, balancing pressure relief efficiency and opening difficulty, and further improving the safety and reliability of the casing structure.

[0099] For example, in this embodiment, the value of S1 / S2 can be 0.03, 0.04, 0.05, or 0.06, or it can be any range formed by the two values ​​mentioned above.

[0100] The housing structure of this embodiment also includes a terminal post 3, which serves as the current output terminal of the battery. The terminal post can be made of aluminum, copper-aluminum composite material, etc. The housing structure 1 includes a housing body 10, and the terminal post 3 is disposed on one of the walls of the housing body 10. As a variation, the housing structure 1 includes a housing body 10 and a cover plate 14. An opening is formed on the housing body 10, and the cover plate 14 is placed over the opening of the housing body 10 and fixed by a sealing structure to ensure the stability and safety of the internal environment of the battery. The terminal post 3 can also be disposed on the cover plate 14 and insulated from the housing body 10.

[0101] In some embodiments, combined with Figure 1 As shown, the shell structure also includes a pole post 3. The pressure relief valve 2 and the pole post 3 are both located on the first wall surface 11, and b satisfies: 0.018≤b≤0.075.

[0102] Since the electrode 3 acts as a flow-through component, it generates significant heat during operation. If both the pressure relief valve 2 and the electrode 3 are located on the first wall surface 11, the local temperature of the first wall surface 11 may become excessively high, affecting the normal operation of the pressure relief valve 2 and increasing the risk of abnormal bursting. Therefore, it is necessary to strictly control the residual thickness ratio b of the weak point 21 to ensure that the first wall surface 11 maintains structural stability under high-temperature conditions, avoiding malfunction of the pressure relief valve 2 due to localized overheating, thereby effectively reducing safety risks.

[0103] In some other embodiments, the housing structure further includes a pole post 3, which is disposed on the second wall surface 15. The second wall surface 15 and the first wall surface 11 are disposed opposite each other on both sides of the housing structure, and b satisfies: 0.025≤b≤0.08.

[0104] The pressure relief valve 2 is located on the first wall surface 11, and the terminal post 3 is located on the second wall surface 15. The second wall surface 15 and the first wall surface 11 are located opposite each other on both sides of the casing structure, achieving thermoelectric separation and improving the battery's safety performance. At this time, by controlling the residual thickness ratio b of the weak part 21, it is possible to ensure that the pressure relief valve 2 opens in a timely manner under high temperature and high pressure, while avoiding the possibility of the terminal post 3 being accidentally pushed out due to excessive opening pressure.

[0105] In some embodiments, when c% satisfies: c%≥99.5%, b satisfies: 0.01≤b≤0.075; In some embodiments, when c% satisfies: 60%≤c%<99.5%, b satisfies: 0.02≤b≤0.09.

[0106] When the content of c is high, the overall strength of the shell structure 1 is also higher, making it more difficult for the pressure relief valve 2 to open, which increases the difficulty of heat dissipation during thermal runaway. When c% satisfies: c% ≥ 99.5%, by further controlling b within the range of 0.01 ≤ b ≤ 0.075, the gas can quickly open the weak part 21 of the pressure relief valve 2 during battery thermal runaway, so that the hot gas can be discharged in time. When c% satisfies: 60% ≤ c% ≤ 99.5%, by further controlling b within the range of 0.01 ≤ b ≤ 0.075, it is ensured that it responds quickly at high temperatures and remains stable under normal conditions.

[0107] In some embodiments, the housing structure includes an Al element, where b satisfies: 0.2 ≤ b ≤ 0.8. The inclusion of the Al element in the housing structure facilitates the opening of the pressure relief valve, allowing for a larger adjustment of the residual thickness of the weak section 21 to prevent abnormal opening of the pressure relief valve under normal conditions.

[0108] In some embodiments, the shell structure is cylindrical, satisfying: 5≤c·b·a≤24.

[0109] Because the cylindrical shell structure experiences symmetrical stress under thermal expansion and mechanical stress, its deformation is minimal during long-term cycling, thereby improving the stability and reliability of the pressure relief valve 2 and reducing the risk of pressure relief failure due to shell deformation. Furthermore, the cylindrical shell structure allows for better stress dispersion when the battery is subjected to external impacts, enhancing the overall structure's impact resistance and effectively preventing shell breakage. By appropriately selecting the range of values ​​for c·b·a, the shell structure maintains excellent performance under both high temperature and impact environments, ensuring timely response of the pressure relief valve while preventing false triggering.

[0110] In some embodiments, the shell structure is a quadrangular prism that satisfies: 1.5≤c·b·a≤20.

[0111] When the casing structure is a rectangular prism, the rectangular prism shape has a greater advantage in space utilization. However, due to the uneven stress distribution on each side of the rectangular prism structure, local stress concentration is prone to occur, increasing the risk of casing deformation. Under thermal expansion and mechanical stress, local stress concentration is more likely to occur, and edges or corners are more susceptible to damage. It is necessary to precisely control the values ​​of c·b·a to balance the forces on each side, prevent local deformation, and thus ensure that the casing structure remains stable under high temperature and impact environments. This allows for timely pressure relief, avoids false triggering, and improves the overall safety of the battery.

[0112] In some embodiments, the thickness b2mm of the first wall 11 satisfies: 0.2mm≤b2mm≤2.0mm.

[0113] By limiting the thickness b2mm of the first wall 11 to within the range of 0.2mm≤b2mm≤2.0mm, sufficient strength is ensured to resist external impact and internal pressure; the wall thickness is prevented from increasing the weight, and good thermal conductivity is guaranteed. Thus, while ensuring strength, the lightweight requirement is met, avoiding the increase in weight and reduced heat dissipation efficiency caused by excessive thickness b2 of the first wall 11, and reducing the processing difficulty of the residual thickness of the weak part 21.

[0114] For example, in this embodiment, the value of b2mm can be 0.2mm or 0.3mm or 0.4mm or 0.5mm or 0.8mm or 1mm or 1.3mm or 1.5mm or 1.8mm or 1.92mm or 2mm, or it can be a range formed by any two of the above values.

[0115] In some embodiments, the residual thickness b1mm of the weak portion 21 is within the range of: 0.02mm≤b1mm≤0.25mm.

[0116] By precisely controlling the value of b1, the weak part 21 is ensured to have sufficient structural strength under extreme conditions to prevent the casing from cracking. At the same time, the opening sensitivity of the pressure relief valve 2 is optimized to further improve the overall safety and reliability of the battery system.

[0117] For example, in this embodiment, the value of b1mm can be 0.02mm or 0.03mm or 0.05mm or 0.08mm or 0.1mm or 0.12mm or 0.15mm or 0.18mm or 0.23mm or 0.25mm, or it can be any range formed by any two of the above values.

[0118] In some embodiments, the housing structure includes a housing body 10 and a cover plate 14, the wall thickness of the housing body 10 is less than the wall thickness of the cover plate 14, and the pressure relief valve 2 is disposed on the housing body 10, satisfying: 0.01≤b≤0.08.

[0119] Since the wall thickness of the shell body 10 is less than that of the cover plate 14, the pressure relief valve 2 is located on the shell body 10, which makes the opening sensitivity of the pressure relief valve 2 on the shell body 10 higher and can be started under lower pressure. It is necessary to control the value range of the formula c·b·a, not only to ensure that the pressure relief valve 2 can be opened smoothly under high temperature and high pressure environment, but also to avoid premature opening of the pressure relief valve 2 due to its thin wall thickness.

[0120] In some other embodiments, the housing structure includes a housing body 10 and a cover plate 14, the wall thickness of the housing body 10 is less than the wall thickness of the cover plate 14, and the pressure relief valve 2 is disposed on the cover plate 14, satisfying: 0.02≤b≤0.09.

[0121] Since the wall thickness of the shell body 10 is less than the wall thickness of the cover plate 14, and the pressure relief valve 2 is set on the cover plate 14, the opening stability of the pressure relief valve 2 on the cover plate 14 is higher. It is necessary to precisely control the value range of the formula c·b·a to ensure that the pressure relief valve 2 can be reliably opened in the event of thermal runaway, while avoiding opening delay caused by the difference in wall thickness, and further improving the overall safety performance.

[0122] In some embodiments, the following condition is satisfied: 4 ≤ c·b·a ≤ 18.

[0123] The housing structure 1 provided in the embodiments of the present invention achieves lightweighting by comprehensively controlling the relationship between a, b, and c, thereby preventing abnormal explosion of the battery during normal charging and discharging, improving the energy density of the battery, and ensuring that the pressure relief valve 2 can open in time during battery thermal runaway to effectively dissipate internal heat and prevent the housing from exploding, thus achieving both lightweighting and safety.

[0124] According to an embodiment of the present invention, in another aspect, a battery is also provided, comprising: The battery cell 4; and the housing structure as described above, wherein a cavity is formed inside the housing structure, the cavity being adapted to accommodate the battery cell 4.

[0125] In this embodiment, the battery can specifically be a cylindrical battery made in a wound form. The battery cell 4 includes a cell body 41 and tabs, wherein the tabs can include a positive tab 42 and a negative tab 43.

[0126] As a key component of the battery, the tab is used to transmit and extract the internal current of the cell. The tab can be made of the same material as the current collector. For example, the tab can be made of at least one of the following: silver-plated aluminum, silver-plated stainless steel, stainless steel, copper, aluminum, nickel, carbon, or titanium. Furthermore, the tab can be cut from the current collector or be a separately formed metal part. It is understood that the positive tab 42 is electrically connected to the positive electrode plate in the cell body 41, and the negative tab 43 is electrically connected to the negative electrode plate in the cell body 41.

[0127] In some embodiments, the battery cell 4 includes a battery cell body 41 and a positive electrode tab 42 and a negative electrode tab 43; The positive electrode tab 42 and the negative electrode tab 43 are located on the same side of the cell body 41 and are set on the same side as the pressure relief valve 2; b satisfies: 0.02≤b≤0.08.

[0128] The positive electrode tab 42 and the negative electrode tab 43 are located on the same side of the cell body 41. The positive electrode tab 42 and the negative electrode tab 43 can be electrically connected to the terminal post respectively; or one of them can be electrically connected to the terminal post and the other can be electrically connected to the battery casing structure 1.

[0129] When the positive electrode tab 42 and the negative electrode tab 43 are located on the same side of the cell body 41, the current path can be effectively shortened and the internal resistance reduced. Furthermore, when the positive electrode tab 42, the negative electrode tab 43, and the pressure relief valve 2 are located on the same side, the tabs generate significant heat during operation due to their overcurrent function. This can easily lead to excessively high local temperatures on the first wall surface 11, affecting the normal operation of the pressure relief valve 2 and increasing the risk of abnormal bursting. Therefore, it is necessary to strictly control the residual thickness ratio b of the weak point 21 to ensure that the first wall surface 11 maintains structural stability under high-temperature conditions, avoiding malfunction of the pressure relief valve 2 due to local overheating, thereby effectively reducing safety risks.

[0130] In some embodiments, the battery cell 4 includes a battery cell body 41 and a positive electrode tab 42 and a negative electrode tab 43; The positive electrode tab 42 and the negative electrode tab 43 are located on the same side of the cell body 41 and are located on the opposite side of the pressure relief valve 2; b satisfies: 0.01≤b≤0.07.

[0131] When the positive electrode tab 42 and the negative electrode tab 43 are located on the same side of the cell body 41, the current path can be effectively shortened and the internal resistance reduced. Furthermore, when the tabs and the pressure relief valve 2 are located on opposite sides, thermoelectric separation is achieved, improving battery safety. However, due to the limited internal space of the casing structure, if the pressure relief valve 2 cannot release the heat inside the casing structure in time, the heat inside the casing structure will also impact the side where the electrode post is located, causing the connection between the electrode post 3 and the casing to fail, and the electrode post 3 to be pushed out, leading to electrical connection failure. At this point, by controlling the residual thickness ratio b of the weak part 21, it is possible to ensure the timely opening of the pressure relief valve 2 under high temperature and high pressure, while also preventing the electrode post 3 from being accidentally pushed out due to excessive opening pressure.

[0132] In some embodiments, the battery cell 4 includes a battery cell body 41 and a positive electrode tab 42 and a negative electrode tab 43; The positive electrode tab 42 and the negative electrode tab 43 are located on opposite sides of the cell body 41; b satisfies: 0.02≤b≤0.075.

[0133] The positive electrode tab 42 and the negative electrode tab 43 are located on opposite sides of the cell body 41. The positive electrode tab 42 and the negative electrode tab 43 can be electrically connected to the terminal post respectively; or one of them can be electrically connected to the terminal post and the other can be electrically connected to the battery casing structure 1.

[0134] The positive electrode tab 42 and the negative electrode tab 43 are located on opposite sides of the cell body 41, which will cause the current path of one of the tabs to become longer, the current path to increase, and the internal resistance to rise, which will easily lead to large heat generation inside the battery. By controlling the residual thickness ratio b of the weak part 21, the pressure relief valve 2 can be guaranteed to open smoothly, while reducing the risk of abnormal opening, and ensuring the stability and safety of the battery under high temperature and high pressure environment.

[0135] In some embodiments, the battery cell 4 includes a positive electrode and a negative electrode, wherein the thickness of the positive electrode is fμm, satisfying: 80μm≤fμm≤150μm.

[0136] As the thickness f of the positive electrode increases, the internal resistance of the cell also increases, leading to an increase in heat generation. It is necessary to further control the range of values ​​of the formula c·b·a to ensure that the pressure relief valve 2 can respond in a timely manner under high temperature and high pressure conditions, reasonably control the opening difficulty, and further improve the safety and reliability of the shell structure.

[0137] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Although embodiments of the present 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 present invention, and all such modifications and variations fall within the scope defined by the present invention.

Claims

1. A shell structure, characterized in that, The shell structure includes Ti element; A pressure relief valve (2) is provided on the first wall surface (11) of the shell structure, and the burst pressure of the pressure relief valve (2) is a MPa; the shell structure is cylindrical; The pressure relief valve (2) includes a weak part (21), the remaining thickness of the weak part (21) is b1, the thickness of the first wall surface (11) is b2, and the ratio of the remaining thickness of the weak part (21) is b, where b = b1 / b2; The mass percentage of Ti in the shell structure relative to the total mass of all elements in the shell structure is c%; where 92.36% ≤ c% ≤ 99.99%; And it satisfies: 3.05≤c·b·a≤24.

2. The shell structure according to claim 1, characterized in that, The aMPa value satisfies: 1.3MPa≤aMPa≤2.6MPa; And / or, the b satisfies: 0.01≤b≤0.

1.

3. The shell structure according to claim 1, characterized in that, The first wall surface (11) is partially formed with a groove, which forms the weak part (21), and b satisfies: 0.02≤b≤0.

08.

4. The shell structure according to claim 3, characterized in that, The groove has an opening (51) and a bottom wall (52), the width of which is greater than the width of the bottom wall (52).

5. The shell structure according to claim 4, characterized in that, The width of the groove gradually decreases along the direction from the opening (51) toward the bottom wall (52).

6. The shell structure according to claim 3, characterized in that, Along the width direction of the groove, the ratio of the width direction of the groove to the size of the first wall surface (11) ranges from 0.2 to 0.

55.

7. The shell structure according to claim 4, characterized in that, The groove also includes a sidewall (53) located between the opening (51) and the bottom wall (52), and the sidewall (53) and the bottom wall (52) form an arc-shaped transition portion (54).

8. The shell structure according to claim 1, characterized in that, The pressure relief valve (2) includes a valve plate portion (22), and the weak portion (21) surrounds the valve plate portion (22) to form a closed ring, wherein b satisfies: 0.025≤b≤0.08; Alternatively, the pressure relief valve (2) may further include a compaction part (12), the weak part (21) is disposed around the outer periphery of the valve plate part (22) and forms a non-closed ring, the compaction part (12) is formed in the area of ​​the ring where the weak part (21) is not disposed; the b satisfies: 0.02≤b≤0.

07.

9. The shell structure according to claim 3, characterized in that, The shell structure is formed with a first groove (23), and a second groove (24) is formed in the first groove (23), wherein b satisfies: 0.015≤b≤0.08; The housing structure has an internal cavity suitable for accommodating the battery cell; The second groove portion (24) includes a second inner groove portion (241) with an opening facing the cavity and / or the second groove portion (24) includes a second outer groove portion (242) with an opening facing away from the cavity.

10. The shell structure according to claim 9, characterized in that, The housing structure forms a cavity suitable for accommodating the battery cell; the second groove portion (24) includes a second inner groove portion (241) with an opening facing the cavity and a second outer groove portion (242) with an opening away from the cavity. The second inner groove portion (241) is disposed opposite to the second outer groove portion (242); the b satisfies: 0.025≤b≤0.

075.

11. The shell structure according to claim 1, characterized in that, The area enclosed by the pressure relief valve (2) is S1mm. 2 The area of ​​the first wall surface (11) is S2mm. 2 Satisfying: 0.03≤S1mm 2 / S2mm 2 ≤0.

06.

12. The shell structure according to claim 1, characterized in that, The housing structure also includes a pole (3), and the pressure relief valve (2) and the pole (3) are both disposed on the first wall surface (11), and b satisfies: 0.018≤b≤0.

075.

13. The shell structure according to claim 1, characterized in that, The shell structure further includes a pole post (3), which is disposed on the second wall surface (15). The second wall surface (15) and the first wall surface (11) are disposed opposite to each other on both sides of the shell structure, and b satisfies: 0.025≤b≤0.

08.

14. The shell structure according to claim 1, characterized in that, When c% satisfies c%≥99.5%, b satisfies 0.01≤b≤0.

075.

15. The shell structure according to claim 1, characterized in that, The shell structure includes Al element, and b satisfies: 0.2≤b≤0.

8.

16. The shell structure according to claim 1, characterized in that, It satisfies: 5≤c·b·a≤24.

17. The shell structure according to claim 1, characterized in that, The thickness b2mm of the first wall (11) satisfies: 0.2mm≤b2mm≤2.0mm.

18. The shell structure according to claim 1, characterized in that, The remaining thickness b1mm of the weak part (21) is within the range of 0.02mm≤b1mm≤0.25mm.

19. The shell structure according to claim 1, characterized in that, The shell structure includes a shell body (10) and a cover plate (14). The wall thickness of the shell body (10) is less than the wall thickness of the cover plate (14). The pressure relief valve (2) is disposed on the shell body (10) and satisfies: 0.01≤b≤0.

08.

20. The shell structure according to claim 1, characterized in that, The shell structure includes a shell body (10) and a cover plate (14). The wall thickness of the shell body (10) is less than the wall thickness of the cover plate (14). The pressure relief valve (2) is disposed on the cover plate (14) and satisfies: 0.02≤b≤0.

09.

21. The shell structure according to claim 1, characterized in that, It satisfies: 4≤c·b·a≤18.

22. A battery, characterized in that, include: Battery cell (4); as well as The housing structure as described in any one of claims 1 to 21 above, wherein a cavity is formed inside the housing structure, the cavity being adapted to accommodate the battery cell (4).

23. The battery according to claim 22, characterized in that, The battery cell (4) includes a battery cell body (41), a positive electrode tab (42), and a negative electrode tab (43). The positive electrode tab (42) and the negative electrode tab (43) are located on the same side of the cell body (41) and are set on the same side as the pressure relief valve (2); the value of b satisfies: 0.02≤b≤0.

08.

24. The battery according to claim 22, characterized in that, The battery cell (4) includes a battery cell body (41), a positive electrode tab (42), and a negative electrode tab (43). The positive electrode tab (42) and the negative electrode tab (43) are located on the same side of the cell body (41) and are located on the opposite side of the pressure relief valve (2); the value of b satisfies: 0.01≤b≤0.

07.

25. A battery pack, characterized in that, include: The enclosure includes a housing and a plurality of batteries as described in any one of claims 22 to 24, the housing comprising a bottom plate and a plurality of side plates, the batteries being fixed to the bottom plate of the housing.

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