Battery cell and application

Abstract

This invention provides a battery cell and its application, relating to the field of battery technology. Specifically, the battery cell includes a cell and a cover plate; the cover plate is provided with a pressure relief valve composite diaphragm, including a pressure relief metal sheet, and an adhesive transition layer and a reinforcing material layer sequentially disposed on the surface of the pressure relief metal sheet away from the cell, and several V-shaped grooves are provided on the edge of the pressure relief metal sheet; the cover plate is also provided with a raised detonation point, which is 2mm~10mm away from the pressure relief valve composite diaphragm, and the raised detonation point is located on the side of the pressure relief valve composite diaphragm away from the cell. This invention provides a novel pressure relief structure that can achieve high reliability in pressure relief under large gas flow, and can ensure accurate detonation of the battery in the event of thermal runaway or cover plate deformation, ensuring that the cell does not experience safety hazards such as explosion or fire.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically, to a battery cell and its application. Background Technology

[0002] With the application and promotion of new energy vehicles, the energy density and fast charging capability of battery cells have improved, and the cell material system has been rapidly upgraded, resulting in a year-on-year increase in the electrochemical activity inside the cell. When the cell experiences thermal runaway, the amount and rate of gas production inside the cell increase dramatically. Traditional cell pressure relief structures are unable to cope with this change and cannot effectively and timely discharge large amounts of gas, increasing the risk of cell safety runaway.

[0003] Traditional battery cell pressure relief structures employ a lower support and C-shaped notches for airflow guidance and explosion protection. Specifically, the lower support is a key component in the pressure relief structure, typically installed at a specific location on the bottom or side of the cell. It provides a supporting foundation for the entire pressure relief structure, ensuring its stability within the cell. C-shaped notches are usually located on the cell's cover plate, created by machining processes such as stamping and cutting to form weak areas. When the cell is operating normally, the C-shaped notches remain intact, sealing the interior and preventing leakage of electrolytes and other substances. When the cell experiences thermal runaway or other abnormal conditions, the internal pressure rises sharply. The C-shaped notches, acting as stress concentration areas, will rupture first, opening the pressure relief channel and releasing the high-pressure gas, thus providing explosion protection.

[0004] The aforementioned traditional pressure relief structure of battery cells has certain technical defects: when the C-shaped groove breaks, there are problems such as obstructed airflow, deformation of the cover plate under thermal runaway conditions, and deformation of the pressure relief valve along with the cover plate. This can lead to deviations in the pressure relief valve's burst pressure, or even the pressure relief valve failing to open, resulting in unsafe and uncontrolled battery cell operation. Therefore, it is necessary to further adjust and upgrade the battery cell's pressure relief structure to match the rapidly evolving battery cell structure and performance.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The primary objective of this invention is to provide a battery cell, mainly relating to the design of pressure relief or explosion-proof functional components in the battery cover, to address the shortcomings of current processes where pressure relief valves (such as conventional structures with brackets and C-shaped grooves) fail to meet the safety performance requirements of highly active batteries during thermal runaway, resulting in defects such as the inability to quickly expel hot air, deformation of the cover or pressure relief valve, deviation of the pressure relief valve's burst pressure, or even failure to open the valve.

[0007] A second objective of the present invention is to provide a battery or electrical device.

[0008] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: A battery cell, the battery cell comprising a battery cell and a cover plate; The cover plate is provided with a pressure relief valve composite diaphragm; the pressure relief valve composite diaphragm includes: a pressure relief metal sheet, and an adhesive transition layer and a reinforcing material layer sequentially disposed on the surface of the pressure relief metal sheet away from the battery cell, and a number of V-shaped grooves are provided on the edge of the pressure relief metal sheet; The cover plate is also provided with a raised detonation point; the distance between the raised detonation point and the pressure relief valve composite diaphragm is 2mm~10mm, and the raised detonation point is located on the side of the pressure relief valve composite diaphragm away from the battery cell.

[0009] Preferably, the cover plate is made of aluminum alloy; preferably, the thickness of the cover plate is 1.5mm to 3.5mm.

[0010] Preferably, the pressure relief metal sheet is made of aluminum alloy, more preferably one of Al 3003-H14, MFX2 O-state aluminum alloy, and Al 1060-H18; preferably, the thickness of the pressure relief metal sheet is 0.4mm~0.8mm.

[0011] Preferably, the material of the bonding transition layer includes at least one of PP, EVA, EEA, EAA, EVAL, APAO, PES, PU, ​​PA, styrene and its block copolymers, SBR, PVDF, and PAA; preferably, the thickness of the bonding transition layer is 10μm to 100μm.

[0012] Preferably, the material of the reinforcing layer includes fiber-based reinforcing materials, inorganic reinforcing materials, and organic reinforcing materials; the fiber-based reinforcing materials include at least one of glass fiber and carbon nanofiber; the inorganic reinforcing materials include at least one of alumina, silicon oxide, calcium oxide, zirconium oxide, and magnesium oxide; and the organic reinforcing materials include at least one of PET, PP, nylon, polyimide, and epoxy resin; preferably, the thickness of the reinforcing layer is 0.1 mm to 1.0 mm; more preferably, the mass ratio of the fiber-based reinforcing material, the inorganic reinforcing material, and the organic reinforcing material is (1 to 4):(6 to 10):(80 to 100).

[0013] Preferably, in the horizontal direction, the distance between the reinforcing material layer and the inner edge of the notch is 0~5mm.

[0014] Preferably, the number of V-shaped grooves is 2 to 10; preferably, the opening angle of the V-shaped grooves is 45° to 80°.

[0015] Preferably, a C-shaped groove is provided on the composite diaphragm of the pressure relief valve in the area near the terminal post of the battery cell, and the V-shaped groove is evenly distributed around the C-shaped groove; more preferably, the distance between any two adjacent V-shaped grooves and C-shaped grooves is 1.5mm to 3mm; even more preferably, the depth of the V-shaped groove is 30% to 95% of the depth of the C-shaped groove.

[0016] A battery or electrical device, comprising the aforementioned battery cell.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention provides a battery cell with a specific structure, mainly involving the optimization of the cover plate and the pressure relief valve in the cover plate. Specifically, this invention achieves a cumulative improvement of more than 100% in the accuracy of the pressure relief structure through the following three aspects: a) composite reinforcing material layer on the basis of traditional pressure relief sheet; b) forming multiple local explosion points through V-shaped grooves; and c) setting raised explosion points on the composite film. This invention can be matched with multiple models of battery cells or battery types for different application scenarios to ensure accurate pressure relief of the battery under thermal runaway and cover plate deformation conditions, and to ensure that the battery cell does not explode, catch fire or other safety accidents.

[0018] (2) The present invention proposes a C-type grooved pressure relief valve structure that works in conjunction with a V-type groove to form multiple local burst weak points, optimize pressure relief consistency, and improve pressure relief accuracy by more than 30%.

[0019] (3) The present invention forms a pull ring composite pressure relief valve by setting a raised detonation point above the pressure relief valve. Under the condition that the cover plate deformation is ≥4mm, the raised detonation point is used as a support point, and a shear force is formed between it and the composite diaphragm of the pressure relief valve, thereby increasing the pressure relief accuracy of the pressure relief valve and improving the pressure relief accuracy by more than 50%.

[0020] (4) Based on the traditional aluminum metal pressure relief sheet, the present invention thermally composites a layer of high-strength material as a reinforcing material layer, which effectively suppresses the deformation of the pressure relief valve, improves the pressure relief accuracy by 25%, and improves the pressure relief accuracy of the pressure relief valve to ±0.05MPa. Attached Figure Description

[0021] 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.

[0022] Figure 1 A schematic diagram of the structure of a feasible pressure relief valve composite diaphragm according to the present invention is provided; Figure 2 A cross-sectional structural schematic diagram of the cover plate according to an embodiment of the present invention is provided; Figure 3 A top view of a single battery cell according to an embodiment of the present invention is provided. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. 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. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0024] 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 the 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 the 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.

[0025] 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 based on the specific circumstances.

[0026] The first aspect of the present invention is to provide a battery cell, the battery cell including a cell and a cover plate; obviously, the battery cell also contains necessary components such as a housing, electrical connectors, and insulation components for maintaining the function or structure of the battery cell, which are not limited in any way in the present invention. The present invention mainly focuses on the cover plate and the pressure relief functional components disposed on the cover plate, and provides detailed limitations and descriptions.

[0027] Specifically, a pressure relief valve composite diaphragm is provided on the cover plate; the pressure relief valve composite diaphragm includes: a pressure relief metal sheet, and an adhesive transition layer and a reinforcing material layer sequentially disposed on the surface of the pressure relief metal sheet away from the battery cell, and several V-shaped grooves are provided on the edge of the pressure relief metal sheet; the cover plate is also provided with a raised detonation point; the distance between the raised detonation point and the pressure relief valve composite diaphragm is 2mm~10mm, and the raised detonation point is disposed on the side of the pressure relief valve composite diaphragm away from the battery cell.

[0028] In a preferred embodiment, the cover plate is made of aluminum alloy, more preferably Al 3003-H14.

[0029] In a preferred embodiment, the thickness of the cover plate is 1.5mm to 3.5mm, including but not limited to any one or any two of the following values: 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, and 3.5 (mm).

[0030] In a preferred embodiment, the pressure relief valve composite diaphragm is recessed on the surface of the cover plate, and the recess depth of the pressure relief valve composite diaphragm is 75% to 95% of the thickness of the cover plate. It is understood that, in the vertical direction, the pressure relief metal sheet in this invention is positioned closer to the battery cell than the cover plate, and since the total thickness of the pressure relief valve composite diaphragm is much lower than that of the cover plate, this recessed structure is formed.

[0031] In a preferred embodiment, the pressure relief metal sheet is made of aluminum alloy, more preferably one of Al3003-H14, MFX2 O-state aluminum alloy, and Al 1060-H18.

[0032] In a preferred embodiment, the thickness of the pressure relief metal sheet is 0.4mm to 0.8mm, including but not limited to any one or any two of 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, and 0.8 (mm), and more preferably 0.5mm.

[0033] In a preferred embodiment, the adhesive transition layer is made of at least one of the following materials: PP (polyethylene), EVA (ethylene-vinyl acetate copolymer), EEA (ethylene-ethyl acrylate copolymer), EAA (ethylene-acrylic acid copolymer), EVAL (ethylene-vinyl acetate-vinyl alcohol terpolymer), APAO (ethylene-propylene-1, butene polymer), PES (polyester), PU (polyurethane), PA (polyamide), styrene and its block copolymers, SBR (styrene-butadiene rubber), PVDF (polyvinylidene fluoride), and PAA (polyacrylic acid). More preferably, the adhesive transition layer is made of PP.

[0034] In a preferred embodiment, the thickness of the bonding transition layer is 10μm to 100μm, including but not limited to any one or any two of the following values: 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100 (μm), with 30μm being more preferred.

[0035] In a preferred embodiment, the reinforcing material layer is made of at least one of glass fiber, carbon nanofiber, PET, PP, nylon, polyimide, epoxy resin, alumina, silicon oxide, calcium oxide, zirconium oxide, and magnesium oxide.

[0036] In a more preferred embodiment, the material of the reinforcing layer includes fiber-based reinforcing materials, inorganic reinforcing materials, and organic reinforcing materials. The fiber-based reinforcing materials include at least one of glass fiber and carbon nanofiber. The inorganic reinforcing materials include at least one of alumina, silicon oxide, calcium oxide, zirconium oxide, and magnesium oxide. The organic reinforcing materials include at least one of PET, PP, nylon, polyimide, and epoxy resin.

[0037] In a more preferred embodiment, the mass ratio of the fiber-based reinforcing material, the inorganic reinforcing material, and the organic reinforcing material is (1~4):(6~10):(80~100).

[0038] In a more preferred embodiment, the reinforcing material layer comprises a combination of carbon nanofibers, PP, and alumina.

[0039] In a preferred embodiment, the thickness of the reinforcing material layer is 0.1 mm to 1.0 mm, including but not limited to any one or any two of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0 (mm), and more preferably 0.5 mm.

[0040] In a preferred embodiment, with the thickness direction as the vertical direction, the distance between the reinforcing material layer and the inner edge of the notch in the horizontal direction is 0-5 mm, including but not limited to any one or any two of the following values: 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5 (mm). More preferably, 2 mm is used. It is worth noting that the "notch" mentioned here includes, but is not limited to, the V-shaped notch defined in this invention. The aforementioned distance relationship exists for any notch, meaning the reinforcing material layer should not extend beyond the outside of the notch to avoid obstructing airflow release when the notch breaks.

[0041] In a more preferred embodiment, the reinforcing material layer is shaped like a cross, an ellipse, or a shape similar to both in the surface direction of the cover plate.

[0042] As an alternative implementation, the pressure relief valve composite diaphragm with a three-layer structure is obtained by coating the material containing the bonding transition layer onto the surface of the pressure relief metal sheet, then loading the reinforcing material layer, and then heat-treating and curing it.

[0043] like Figure 1 The diagram shows a feasible structural schematic of the aforementioned pressure relief valve composite diaphragm. Figure 1 As can be seen, in addition to the necessary pressure relief metal sheet, the bonding transition layer, and the reinforcing material layer, as an optional embodiment, a reinforced bonding layer is further included between the bonding transition layer and the reinforcing material layer to enhance the material adhesion between the two layers; the material of the reinforced bonding layer includes at least one of PP, nylon, polyimide, and epoxy resin polymer, and the thickness of the reinforced bonding layer is 20μm~40μm.

[0044] like Figure 2 The diagram shows a possible cross-sectional structure of the cover plate. Figure 2 As can be seen, in the present invention, the V-shaped groove has the tip of the V close to the battery cell, while the opening of the V is close to the bonding transition layer and the reinforcing material layer.

[0045] In a preferred embodiment, the number of V-shaped grooves is 2 to 10, preferably 4.

[0046] As a preferred embodiment, the opening angle of the V-shaped groove is 45°~80° (it can be understood that the opening angle refers to the angle formed by the two V-shaped sides of the V-shaped groove in cross-section), including but not limited to any one or any two of 45, 50, 55, 60, 65, 70, 75, 80 (°), and more preferably 60°.

[0047] In a preferred embodiment, C-shaped grooves are provided on the composite diaphragm of the pressure relief valve in the area near the terminal post of the battery cell; in some more preferred embodiments, the number of C-shaped grooves is 1 to 4, and the number and distribution of the C-shaped grooves are adaptively adjusted according to the type and specifications of the battery.

[0048] In a more preferred embodiment, the V-shaped grooves are evenly distributed around the C-shaped grooves, and the distance between any two adjacent V-shaped grooves and C-shaped grooves is 1.5mm to 3mm, preferably 2mm.

[0049] In a more preferred embodiment, the depth of the V-shaped groove is 30% to 95% of the depth of the C-shaped groove, including but not limited to any one or any two of the following values: 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, and 95%.

[0050] As a further preferred embodiment, the depth of the V-shaped groove is 50μm~100μm, including but not limited to any one or any two of the values ​​of 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 (μm), and more preferably 64μm; the depth of the C-shaped groove is 70μm~150μm, including but not limited to any one or any two of the values ​​of 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150 (μm), and more preferably 80μm.

[0051] like Figure 2 As shown, the distance between the raised detonation point and the composite diaphragm of the pressure relief valve is also schematically illustrated, that is... Figure 2 The distance between the raised detonation point and the pressure relief valve composite diaphragm is, but is not limited to, any one or any two of the following values: 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10 (mm), preferably 4mm.

[0052] like Figure 2 As shown, it can also be understood that in this invention, the raised detonation point and the cover plate are an integral structure. The raised detonation point has a convex structure, which can be regarded as a cube or cross-shaped structure, and the position of the raised detonation point corresponds to the edge of the pressure relief valve composite diaphragm.

[0053] In a preferred embodiment, the material of the raised detonation point is the same as that of the cover plate, both being aluminum alloy.

[0054] like Figure 3 The diagram shown provides a feasible top-view structural schematic for a single battery cell. Figure 3 As can be seen, the number of raised detonation points is one, and it is located at the center of the edge of the pressure relief valve composite diaphragm. In some preferred embodiments, the number of raised detonation points is one to two.

[0055] A second aspect of the present invention is to provide a battery or electrical device; it is understood that, provided that it includes a battery cell as described in the first aspect, any integrated battery or battery pack, or any electrical device, can be used as an embodiment of this aspect.

[0056] Example 1 like Figure 2 , Figure 3 As shown, the battery cell in this embodiment employs a novel pressure relief structure, including: a reinforcing material layer, a bonding transition layer, a pressure relief metal sheet, V-shaped grooves, a cover plate, and raised detonation points. The reinforcing material layer is made of carbon nanofiber, PP, and alumina (in a mass ratio of 2:90:8), with a thickness of 0.5 mm; the bonding transition layer is made of PP with a thickness of 30 μm; the pressure relief metal sheet is made of MFX2 O-state aluminum alloy with a thickness of 0.5 mm; there are a total of 8 V-shaped grooves, as shown... Figure 3 The pressure relief metal sheet is distributed along its edge, with a V-shaped bevel angle of 60° and a depth of 64μm; there is also a C-shaped groove with a depth of 80μm; the cover plate is made of Al3003-H14 with a thickness of 2.5mm; the raised detonation point is also made of Al3003-H14 with L1 controlled at 2mm; there is a 2mm gap between the reinforcing material layer and the inner edge of the groove.

[0057] Furthermore, the cell size is set to 47.2*208*102, and the positive electrode uses 30% monocrystalline LiNi. 0.90 Co 0.07 Mn 0.03 O2 and 70% polycrystalline LiNi 0.92 Co 0.05 Mn 0.03 The negative electrode uses 420mAh / g fast-charging graphite and nano-silicon carbon, and is assembled using a stacked structure. The number of positive electrode stacks is 126 and the number of negative electrode stacks is 127, resulting in the test battery of this embodiment.

[0058] According to the test results, the battery cell capacity of this embodiment is 185.5Ah, the specific energy of weight is 280Wh / kg, the specific energy of volume is 687Wh / L, the maximum charging rate is 2C, the charging time from 10% to 80% is 20min, and the maximum discharging rate is 5C.

[0059] Example 2 It is basically the same as Example 1, except that there are a total of 4 V-shaped grooves and L1 is controlled to be 4mm.

[0060] Comparative Example 1 It is basically the same as Example 2, except that there is no protruding detonation point, and its corresponding position is only the cover plate surface.

[0061] Comparative Example 2 It is basically the same as Example 2, except that there are no V-shaped grooves.

[0062] Comparative Example 3 It is basically the same as Comparative Example 1, except that there are no V-shaped grooves.

[0063] Comparative Example 4 It is basically the same as Example 2, except that there is no reinforcing material layer and bonding transition layer, and the thickness of the pressure relief metal sheet is 1 mm.

[0064] Comparative Example 5 It is basically the same as Comparative Example 3, except that there is no reinforcing material layer and bonding transition layer, and the thickness of the pressure relief metal sheet is 1 mm.

[0065] Test case (1) The burst pressure test was conducted as follows: Remove the plastic below the metal diaphragm of the pressure relief valve on the cover plate, take 3 empty cells (battery cover plate and battery casing), 1 dry cell (cell cover plate, battery casing and electrode core), pressurize from the side wall of the battery casing, hold the pressure at 0.1MPa for 30s every interval, and record whether the explosion-proof valve is open, the deformation of the battery cover plate and the bottom of the casing and other phenomena; detect and record the explosion relief pressure and pressure relief accuracy of the pressure relief valve by increasing the pressure.

[0066] (2) The hot chamber test was conducted as follows: First, the batteries prepared in each example and comparative example were left to stand for 30 minutes, charged to 3.8V at 1 / 3C (36.67A) constant current and constant voltage, then switched to constant voltage charging, and the current was cut off at 0.05C (5.5A). The batteries were left to stand for 1 hour. Then, they were transferred to a temperature chamber and heated to 80℃ at a rate of 2℃ / min and maintained for 120 minutes. Then, they were heated to 130℃ at a rate of 2℃ / min and maintained at this temperature for 30 minutes. After completing the above test steps, the batteries were observed at the test environment temperature for 1 hour. Then, the temperature chamber was increased by 5℃ at a rate of 2℃ / min and maintained for 30 minutes. This process was repeated until the battery thermal runaway was triggered, and the thermal runaway temperature was recorded.

[0067] (3) Short circuit test is adopted, and the method is as follows: First, let it stand for 30 minutes, charge it to 4.25V with constant current and constant voltage at 1 / 3C (36.67A), switch to constant voltage charging, cut off the current at 0.05C (5.5A), and let it stand for 1 hour; then, use an external circuit with a resistance of 1mΩ to short circuit the positive and negative terminals of each test battery externally until the voltage drops to 0V or the battery triggers thermal runaway, and record the corresponding phenomena.

[0068] Table 1 shows the performance of each embodiment and comparative example in the above test cases.

[0069] Table 1

[0070] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A battery cell, characterized in that, The battery cell includes a cell and a cover plate; The cover plate is equipped with a pressure relief valve composite diaphragm; The pressure relief valve composite diaphragm includes: a pressure relief metal sheet, and an adhesive transition layer and a reinforcing material layer sequentially disposed on the surface of the pressure relief metal sheet away from the battery cell, and a number of V-shaped grooves are provided on the edge of the pressure relief metal sheet; The cover plate is also provided with a raised detonation point; the raised detonation point and the cover plate are an integral structure, and the raised detonation point has a convex structure; the raised detonation point is located in the middle of the edge of the pressure relief valve composite diaphragm; The distance between the raised detonation point and the pressure relief valve composite diaphragm is 2mm to 10mm, and the raised detonation point is located on the side of the pressure relief valve composite diaphragm away from the battery cell.

2. The battery cell according to claim 1, characterized in that, The cover plate is made of aluminum alloy; And / or, the thickness of the cover plate is 1.5mm to 3.5mm.

3. The battery cell according to claim 1, characterized in that, The pressure relief metal sheet is made of aluminum alloy, which includes one of Al 3003-H14, MFX2 O-state aluminum alloy, and Al 1060-H18; And / or, the thickness of the pressure relief metal sheet is 0.4mm~0.8mm.

4. The battery cell according to claim 1, characterized in that, The adhesive transition layer is made of at least one of the following materials: PP, EVA, EEA, EAA, EVAL, APAO, PES, PU, ​​PA, styrene and its block copolymers, SBR, PVDF, and PAA. And / or, the thickness of the bonding transition layer is 10μm~100μm.

5. The battery cell according to claim 1, characterized in that, The material of the reinforcing layer includes fiber-based reinforcing materials, inorganic reinforcing materials, and organic reinforcing materials; The fiber-based reinforcing material includes at least one of glass fiber and carbon nanofiber; the inorganic reinforcing material includes at least one of alumina, silicon oxide, calcium oxide, zirconium oxide, and magnesium oxide; and the organic reinforcing material includes at least one of PET, PP, nylon, polyimide, and epoxy resin. And / or, the thickness of the reinforcing material layer is 0.1 mm to 1.0 mm.

6. The battery cell according to claim 5, characterized in that, The mass ratio of the fiber-based reinforcing material, the inorganic reinforcing material, and the organic reinforcing material is (1~4):(6~10):(80~100).

7. The battery cell according to claim 1, characterized in that, In the horizontal direction, the distance between the reinforcing material layer and the inner edge of the notch is 0~5mm.

8. The battery cell according to claim 1, characterized in that, The number of V-shaped grooves is 2 to 10; And / or, the opening angle of the V-shaped notch is 45°~80°.

9. The battery cell according to claim 1, characterized in that, A C-shaped groove is provided on the composite diaphragm of the pressure relief valve in the area near the electrode post of the battery cell, and the V-shaped groove is evenly distributed around the C-shaped groove; The distance between any two adjacent V-shaped and C-shaped markings is 1.5mm to 3mm; The depth of the V-shaped groove is 30% to 95% of the depth of the C-shaped groove.

10. A battery or electrical device, characterized in that, Includes the battery cell as described in any one of claims 1 to 9.

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