Battery pack, electric equipment and energy storage system

Abstract

The embodiment of the utility model provides a battery pack, electric equipment and an energy storage system. The battery pack comprises a box body, a pressure release valve, a housing and a battery cell, an accommodating cavity is formed in the box body, and the battery cell is arranged in the accommodating cavity. The pressure release valve is mounted in the box body, and when the battery pack is subjected to thermal runaway, gas in the box body can be discharged out of the accommodating cavity of the box body through the pressure release valve, so that the pressure in the accommodating cavity is reduced. And oxygen outside the box body cannot enter the accommodating cavity of the box body through the pressure release valve. The housing is located in the containing cavity and fixed to the box body, the periphery of the pressure release valve is covered with the housing, the housing comprises a net cover, gas in the containing cavity can be transmitted to the pressure release valve through the net cover, foreign matter is not prone to being transmitted to the pressure release valve, and therefore the pressure release valve is not prone to being damaged. The orthographic projection of the mesh enclosure on the box plate provided with the pressure release valve does not coincide with the orthographic projection of the pressure release valve on the box plate. Therefore, the protectiveness of the housing to the pressure release valve is further improved, and the safety of the battery pack is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery pack, an electrical device and an energy storage system. Background Art

[0002] As a carrier of electric energy, battery packs are used in energy storage systems and electrical equipment. In energy storage systems, electric energy is stored and supplied to users through the charging and discharging of battery packs. In electrical equipment (such as new energy vehicles), battery packs are the main power source for new energy vehicles and can be used to drive the entire vehicle. Battery cells are the basic units in battery packs that realize the mutual conversion of chemical energy and electrical energy. With the further improvement of battery cell energy density, the safety issues of battery cells are becoming increasingly prominent. High-energy-density battery cells are prone to thermal runaway under conditions such as collision, overheating, extrusion or puncture, and the battery cells will release a large amount of heat and flammable gases at the moment of thermal runaway. After the battery cell thermal runaway, it is easy to cause a large number of battery cells to have a chain of thermal runaway, which may cause the battery pack to catch fire or even explode.

[0003] In order to improve the safety of battery packs, the industry has begun to apply various solutions, such as thermal and electrical isolation, immersion fire protection, or positive pressure oxygen barrier. Among them, the positive pressure oxygen barrier has gradually begun to be applied in the field of vehicle-mounted equipment and energy storage equipment. Specifically, positive pressure oxygen barrier is achieved by installing a pressure relief valve in the box of the battery pack. Therefore, improving the reliability of the pressure relief valve and reducing the risk of damage to the pressure relief valve are important development directions in this field. Utility Model Content

[0004] The present application provides a battery pack, electrical equipment and energy storage system, which improve the reliability and service life of the pressure relief valve, improve the safety of the battery pack, and facilitate the protection of the electrical equipment and energy storage system when thermal runaway occurs in the battery pack.

[0005] In the first aspect, the present application provides a battery pack, which specifically includes a box, a pressure relief valve, a cover and a battery cell. Among them, there is a accommodating chamber in the box, and the above-mentioned battery cell is arranged in the accommodating chamber. The above-mentioned pressure relief valve is installed in the box. When the pressure in the accommodating chamber increases to a certain extent, the pressure relief valve will be opened. The pressure relief valve is in an activated state, connecting the above-mentioned accommodating chamber and the outside of the box, so that when the battery pack has thermal runaway, the gas in the box can be discharged from the accommodating chamber of the box through the pressure relief valve, so that the pressure in the accommodating chamber is reduced. However, the external oxygen cannot enter the accommodating chamber of the box through the pressure relief valve. The above-mentioned cover is located in the accommodating chamber and fixed to the box. The cover is arranged on the surrounding side of the pressure relief valve to protect the pressure relief valve. The cover includes a mesh cover, so that the gas in the accommodating chamber can be transmitted to the pressure relief valve through the mesh cover, and then discharged from the accommodating chamber through the pressure relief valve. The orthographic projection of the mesh cover on the box board equipped with the pressure relief valve does not overlap with the orthographic projection of the pressure relief valve on the box board. The mesh cover and the pressure relief valve are staggered. Even if flying sparks, foreign matter, or molten plastic fluid passes through the mesh cover, they will not directly splash onto the pressure relief valve, thereby further improving the protection of the cover for the pressure relief valve and further improving the safety of the battery pack.

[0006] In one technical solution, the box body includes a top plate, a bottom plate and side plates, and the side plates connect the top plate and the bottom plate to form the accommodating chamber. The pressure relief valve is specifically installed on the side plate, and the distance between the edge of the mesh cover facing the bottom plate and the bottom plate is smaller than the distance between the edge of the pressure relief valve facing the bottom plate and the bottom plate. From a vertical perspective only, the mesh cover is located below the pressure relief valve. Sparks, foreign matter, or plastic melt fluid and other substances generated by thermal runaway of the battery cell will enter the mesh cover and fall toward the bottom plate under gravity without passing through the pressure relief valve, which is beneficial to further protect the pressure relief valve.

[0007] In one technical solution, the box body includes a top plate, a bottom plate and a side plate, and the side plate connects the top plate and the bottom plate to form the accommodating cavity. The pressure relief valve is specifically installed on the side plate, and the end shell of the cover shell facing the bottom plate has an opening. Sparks, foreign matter or plastic melt fluid and other substances that pass through the mesh cover can flow out of the protective cavity through the opening under the action of gravity, reducing the accumulation of debris in the protective cavity, so as to reduce the risk of the debris blocking the mesh cover or the pressure relief valve.

[0008] Specifically, the end of the end shell close to the side plate is the first end, the end away from the side plate is the second end, the distance between the first end of the end shell and the bottom plate is smaller than the distance between the second end of the end shell and the bottom plate, and the opening is located at the first end of the end shell. The end shell is an inclined end shell or an arc end shell, and the end shell is equivalent to a guide plate, so that the material entering the protective cavity can flow out from the opening more smoothly.

[0009] The opening is located at the edge of the end shell facing the side plate, and there is a gap between the end shell and the side plate of the cover shell. This solution can simplify the preparation process of the cover shell and is conducive to simplifying the assembly process of the cover shell and the box body.

[0010] The width of the above-mentioned gap is greater than or equal to 2 mm, so that general substances can flow out of the protection cavity through the gap.

[0011] In a specific technical solution, the width of the above-mentioned gap is greater than or equal to the mesh size of the mesh cover (such as the diameter of a round hole or the diagonal length of a square hole), so that the material passing through the mesh cover can flow out from the above-mentioned gap.

[0012] In one technical solution, the mesh cover includes two layers of cover surfaces, each of which includes mesh holes. A cooling core is arranged between the two layers of cover surfaces. The cooling core is used to absorb heat. The gas discharged from the pressure relief valve can reduce the temperature to a certain extent, so as to reduce the damage to people or devices outside the battery pack caused by the gas generated by the thermal failure of the battery pack.

[0013] In an optional technical solution, the cooling core includes a phase change material, which absorbs the heat of the high-temperature gas through the phase change of the phase change material, so as to achieve the purpose of cooling by a physical method. In an optional technical solution, the cooling core includes magnesium carbonate, which absorbs heat and undergoes a chemical reaction, so as to achieve the purpose of cooling by a chemical method.

[0014] The housing includes at least two mesh covers to meet the strength requirements of the mesh covers and the pressure relief capacity requirements of the pressure relief valve, and is specifically selected and designed according to factors such as the size of the box or the opening area of ​​the pressure relief valve.

[0015] In one technical solution, the cover shell and the mesh cover are separate structures, the cover shell includes a through hole, and the mesh cover is installed in the through hole of the cover shell, which is conducive to the maintenance of the mesh cover.

[0016] In one technical solution, the cover shell and the mesh cover are an integrated structure. Specifically, the plate shell of the cover shell itself includes a plurality of small holes, and the plurality of small holes form the mesh cover. This solution can improve the structural strength of the cover shell.

[0017] In a second aspect, the present application provides an electrical device, which includes a functional component and a battery pack provided in the first aspect. The battery pack is electrically connected to the functional component, and the battery pack is used to power the functional component. The reliability and service life of the pressure relief valve are improved, and the safety of the battery pack is improved, so as to protect the electrical device when the battery pack has thermal runaway.

[0018] In a third aspect, the present application provides an energy storage system, including a power converter and a battery pack provided in the first aspect above. The power converter is electrically connected to the battery pack; the power converter is used to convert the AC power output by an external AC power source into DC power and output it to the battery pack, and / or the power converter is used to convert the DC power output by the battery pack into AC power and output it to a load or a power grid. The reliability and service life of the pressure relief valve are improved, and the safety of the battery pack is improved, so as to protect the energy storage system when the battery pack has thermal runaway. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the structure of an electrical device in an embodiment of the present application;

[0020] Figure 2 A schematic diagram of the structure of the energy storage system in the embodiment of the present application;

[0021] Figure 3 A schematic diagram of the structure of a battery pack in an embodiment of the present application;

[0022] Figure 4 A schematic diagram of a cross-sectional structure of a battery pack in an embodiment of the present application;

[0023] Figure 5 A schematic diagram of a cross-sectional structure of a battery pack in an embodiment of the present application;

[0024] Figure 6 A schematic diagram of a lateral structure of a battery pack in an embodiment of the present application;

[0025] Figure 7 A schematic diagram of a lateral structure of a battery pack in an embodiment of the present application;

[0026] Figure 8 A schematic diagram of a lateral structure of a battery pack in an embodiment of the present application;

[0027] Fig. 9 A schematic diagram of a lateral structure of a battery pack in an embodiment of the present application;

[0028] Fig.10 A schematic diagram of the structure of a battery pack in an embodiment of the present application.

[0029] Reference numerals:

[0030] 100-energy storage system; 110-power converter;

[0031] 200-external AC power supply; 300-grid;

[0032] 1-Functional components; 2-Battery pack;

[0033] 21-box body; 211-side panel;

[0034] 212-top plate; 213-bottom plate;

[0035] 22-pressure relief valve; 23-cover;

[0036] 231-mesh cover; 2311-cover surface;

[0037] 2312-cooling core; 232-plate shell;

[0038] 233-end shell; 2331-first end;

[0039] 2332-second end; 234-top shell;

[0040] 235-side shell; 236-opening;

[0041] 24-cell; X-horizontal;

[0042] Y - vertical direction. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the present application clearer, the embodiments of the present application will be further described in detail below in conjunction with the accompanying drawings. However, the example implementation can be implemented in various forms and should not be construed as being limited to the implementations set forth herein. The same reference numerals in the figures represent the same or similar structures, and thus their repeated description will be omitted. The words expressing position and direction described in the embodiments of the present application are all illustrated by taking the accompanying drawings as examples, but changes may be made as needed, and the changes made are all included in the scope of protection of the present application. The drawings of the embodiments of the present application are only used to illustrate the relative position relationship and do not represent the true proportion.

[0044] It should be noted that specific details are described in the following description to facilitate understanding of the present application. However, the embodiments of the present application can be implemented in a variety of other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the embodiments of the present application. Therefore, the present application is not limited to the specific implementation methods disclosed below.

[0045] In order to facilitate the understanding of the battery pack, electrical equipment and energy storage system provided in the embodiments of the present application, the application scenarios are first introduced below. The battery cells of the battery pack in the embodiments of the present application can be battery cells formed by secondary batteries such as lithium-ion batteries, lead-acid batteries, sodium batteries, magnesium batteries, aluminum batteries and potassium batteries. Among them, in the embodiments of the present application, secondary batteries (rechargeable batteries) are also called rechargeable batteries, power batteries or storage batteries, and specifically refer to batteries that can continue to be used by activating active substances by charging after the battery is discharged. The battery pack may catch fire during use due to collisions or acupuncture and other reasons. The positive pressure oxygen barrier solution is currently a commonly used one that has gradually begun to be used in the field of vehicle-mounted equipment and energy storage equipment. Specifically, the positive pressure oxygen barrier solution is achieved by installing a pressure relief valve in the battery pack case. When the battery pack fails thermally, the pressure in the battery pack case increases accordingly. When the pressure in the battery pack case increases to the start threshold of the pressure relief valve, the pressure relief valve opens, and the pressure in the battery pack is released through the pressure relief valve. The specific manifestation is that the high-temperature gas in the case flows out of the battery pack case from the pressure relief valve to reduce the probability of explosion of the battery pack. In addition, it is difficult for external oxygen to enter the case through the pressure relief valve, so that the battery cells inside the battery pack are not prone to large-scale combustion. Therefore, the safety of the battery pack can be improved by equipping the battery pack with a pressure relief valve. Improving the reliable operation of the pressure relief valve has become an important means to improve the safety of the battery pack. For this reason, the present application provides a battery pack, electrical equipment and energy storage system. By improving the reliable operation of the pressure relief valve of the battery pack, the safety of the battery pack and the electrical equipment and energy storage system using the battery pack are improved.

[0046] At present, in people's lives and production, the operation of electrical equipment is inseparable from the supply of electricity. In one scenario, the electrical equipment is directly equipped with a battery pack, and the battery pack is used to power the electrical equipment. For example, the electrical equipment can be a means of transportation such as an electric vehicle, an electric bicycle, or an electric ship. Alternatively, in one scenario, an energy storage system is used to power the electrical equipment, and the energy storage system includes a battery pack, which stores electrical energy and is used to power the electrical equipment. In this scenario, the electrical equipment can be household appliances or industrial equipment.

[0047] Figure 1 A schematic diagram of the structure of an electrical device in an embodiment of the present application is shown in FIG. Figure 1 As shown, the electric device in the embodiment of the present application includes a battery pack 2 and a functional component 1, the battery pack 2 is electrically connected to the functional component 1, and the battery pack 2 is used to supply power to the functional component 1 so that the functional component 1 operates normally. The electric device in the embodiment of the present application refers to the electric device directly equipped with the battery pack 2, such as Figure 1In the illustrated embodiment, an electric vehicle is taken as an example. In other embodiments, the electrical equipment may also be a vehicle such as an electric vehicle, an electric bicycle or an electric ship, or a mechanical device that requires electric drive. Taking an electric vehicle as an example, the functional component 1 is a powertrain, and the battery pack 2 supplies power to the powertrain to drive the powertrain to operate. The powertrain is connected to the wheels of the electric vehicle in a driving manner, so that the powertrain drives the electric vehicle to operate.

[0048] Figure 2 is a schematic diagram of a structure of an energy storage system in an embodiment of the present application, such as Figure 2 As shown, the energy storage system 100 in the embodiment of the present application includes a battery pack 2 and a power converter 110, and the battery pack 2 and the power converter 110 are electrically connected. The power converter 110 is used to convert the AC power output by the external AC power source 200 into DC power and output it to the battery pack 2, and / or the power converter 110 is used to convert the DC power output by the battery pack 2 into AC power and output it to the load or the power grid 300.

[0049] Figure 3 This is a schematic diagram of the structure of a battery pack in an embodiment of the present application. Figure 4 is a schematic diagram of a cross-sectional structure of a battery pack in an embodiment of the present application, such as Figure 4 As shown, in one embodiment, the battery pack 2 of the present application includes a case 21, a pressure relief valve 22, a cover 23 and a battery cell 24. Among them, the case 21 has a containing cavity, and the battery cell 24 and the cover 23 are arranged in the containing cavity. In a specific embodiment, the battery pack 2 includes a plurality of battery cells 24, and the plurality of battery cells 24 are connected in series and / or in parallel to work together. The above-mentioned case 21 includes a plurality of box plates, and the plurality of box plates enclose the above-mentioned containing cavity. The pressure relief valve 22 is installed on the box plate of the case 21. When the pressure relief valve 22 is in an open state, the containing cavity inside the case 21 of the battery pack 2 is connected with the outside of the case 21. The above-mentioned cover 23 is located in the containing cavity and is fixed to the case 21, and the cover 23 is arranged on the surrounding side of the pressure relief valve 22. As shown Figure 4As shown, the cover shell 23 and the box body 21 are enclosed to form a protective cavity, and the pressure relief valve 22 is located in the protective cavity. The cover shell 23 includes a mesh cover 231, and the mesh cover 231 has a hole, so that the protective cavity and the part of the accommodating cavity that accommodates the battery cell 24 are connected. When the battery cell 24 in the box body 21 generates a large amount of gas, the gas can enter the protective cavity from the hole of the mesh cover 231, and then be discharged to the outside of the box body 21 through the pressure relief valve 22. In addition, when the battery cell 24 has thermal runaway, it is also easy to produce flying sparks, foreign matter or plastic melt fluid and other substances. The mesh cover 231 can block the flying sparks, foreign matter or plastic melt fluid to reduce the damage of the above substances to the pressure relief valve 22. For example, foreign matter can be intercepted to reduce the risk of foreign matter getting stuck in the pressure relief valve 22; flying sparks can be reduced, which, on the one hand, reduces the damage to the pressure relief valve 22 caused by sparks; on the other hand, makes it difficult for sparks to be discharged from the pressure relief valve 22 to the outside of the box 21, thereby reducing the risk of fire on the outside of the battery pack 2; in addition, the probability of the molten plastic fluid flowing to the pressure relief valve 22 can be reduced; on the one hand, it reduces the situation where the molten plastic fluid stays in the pressure relief valve 22 and gets stuck in the pressure relief valve 22 after hardening; on the other hand, it also makes it difficult for the molten plastic fluid to flow outside the box 21, thereby protecting the devices outside the battery pack 2.

[0050] In a specific embodiment, the orthographic projection of the mesh cover 231 on the box plate equipped with the pressure relief valve 22 does not overlap with the orthographic projection of the pressure relief valve 22 on the box plate. For example, when the pressure relief valve 22 is installed on the side plate 211 of the box body, the orthographic projection of the mesh cover 231 on the side plate 211 does not overlap with the orthographic projection of the pressure relief valve 22 on the side plate 211, so that the mesh cover 231 and the pressure relief valve 22 are staggered. In this embodiment, even if the above-mentioned flying sparks, foreign matter, or plastic melt fluid and other substances pass through the mesh cover 231, they will not directly splash onto the pressure relief valve 22, so as to further enhance the protection of the cover 23 for the pressure relief valve 22 and further enhance the safety of the battery pack 2.

[0051] The box body 21 includes a top plate 212, a bottom plate 213 and a side plate 211, and specifically may include a plurality of side plates 211, wherein the plurality of side plates 211 are connected in sequence, and the side plates 211 connect the top plate 212 and the bottom plate 213, so that the top plate 212, the bottom plate 213 and the side plates 211 enclose and form the above-mentioned accommodating cavity. In one embodiment, the box body 21 is a cubic structure, and the top plate 212, the bottom plate 213 and the plurality of side plates 211 correspond to the six faces of the cube respectively. In one embodiment, the top plate 212 is the upper horizontal plate of the box body 21, the bottom plate 213 is the lower horizontal plate of the box body 21, and the side plates 211 are the vertical plates on the sides of the box body 21. In one embodiment, the pressure relief valve 22 is installed on the top plate 212; in one embodiment, the pressure relief valve 22 is installed on the side plates 211, so as to protect the pressure relief valve 22.

[0052] like Figure 4As shown, in the embodiment of the present application, the cover 23 includes a plate shell 232 opposite to the pressure relief valve 22, and an end shell 233 opposite to the bottom plate 213 of the box body 21, the plate shell 232 is connected to the end plate, and the mesh cover 231 is arranged on the plate shell 232 of the cover 23. In this embodiment, the side plate 211 and the end plate are directly fixed to the side plate 211 of the box body 21 to form the above-mentioned protection cavity, so as to simplify the structure of the cover 23.

[0053] Figure 5 is a schematic diagram of a cross-sectional structure of a battery pack in an embodiment of the present application, such as Figure 5 As shown, in one embodiment, the cover shell 23 further includes a top shell 234 , which is connected to the plate shell 232 and is located at an end of the plate shell 232 away from the end plate, and the plate shell 232 is connected between the end shell 233 and the top shell 234 .

[0054] Figure 6 is a schematic diagram of a lateral structure of a battery pack in an embodiment of the present application, such as Figure 6 As shown, in one embodiment, the cover shell 23 further includes a side shell 235, and the side shell 235 is connected to both sides of the plate shell 232. Specifically, the side shell 235 is connected to the plate shell 232, the end shell 233 and the top shell 234 respectively, and the cover shell 23 is formed into a bowl-shaped structure. In a specific embodiment, the bowl mouth of the cover shell 23 with the bowl-shaped structure faces the box plate on which the pressure relief valve 22 is installed.

[0055] Figure 7 is a schematic diagram of a lateral structure of a battery pack in an embodiment of the present application, such as Figure 7 As shown, in one embodiment, the cover shell 23 does not include the side shell 235, and the two sides of the cover shell 23 are connected by the side plates 211 of the box body 21 to form a protective cavity.

[0056] In the embodiment of the present application, the mesh cover 231 and the pressure relief valve 22 are arranged in an alternating manner, and there are many options. Figures 4 to 7 As shown, in one embodiment, the distance between the edge of the mesh cover 231 facing the bottom plate 213 and the bottom plate 213 is smaller than the distance between the edge of the pressure relief valve 22 facing the bottom plate 213 and the bottom plate 213. From the vertical direction Y alone, the mesh cover 231 is located below the pressure relief valve 22. In this embodiment, sparks, foreign matter, or plastic melt fluid generated by thermal runaway of the battery cell 24 enter the mesh cover 231 and fall toward the bottom plate 213 under gravity without passing through the pressure relief valve 22, which is conducive to further protecting the pressure relief valve 22.

[0057] Figure 8 is a schematic diagram of a lateral structure of a battery pack in an embodiment of the present application, such as Figure 8As shown, in one embodiment, the mesh cover 231 and the pressure relief valve 22 can also be arranged substantially flush, that is, the mesh cover 231 and the pressure relief valve 22 are arranged staggered along the horizontal direction X. Please refer to Figure 3 In addition to the horizontal direction X and the vertical direction Y, the three-dimensional battery pack also includes a first direction Z. The horizontal direction X, the vertical direction Y and the first direction Z are perpendicular to each other. The plane defined by the horizontal direction X and the vertical direction Y is substantially parallel to the plane where the box plate with the pressure relief valve installed in the box body is located.

[0058] Fig. 9 is a schematic diagram of a lateral structure of a battery pack in an embodiment of the present application, such as Fig. 9 As shown, in some embodiments, in addition to being located below the pressure relief valve 22 in the vertical direction Y, the mesh cover 231 and the pressure relief valve 22 are also staggered in the horizontal direction X.

[0059] The vertical direction Y and the lateral direction X are determined when the battery pack 2 is in use. The vertical direction Y is perpendicular to the bottom plate 213 of the box body 21 , and the lateral direction X is in the plane where the side plate 211 of the box body 21 is located and perpendicular to the numerical direction.

[0060] In addition, in the embodiment of the present application, the number of mesh covers 231 included in a cover shell 23 can also have multiple options. In one embodiment, the sum of the hole areas of the cover shell 23 is greater than or equal to the area of ​​the opening 236 of the pressure relief valve 22, so that the gas in the accommodating chamber can be smoothly transmitted to the pressure relief valve 22 through the holes of the cover shell 23, so as to fully utilize the pressure relief capacity of the pressure relief valve 22 without reducing the pressure relief capacity of the pressure relief valve 22 due to the setting of the cover shell 23. The cover shell 23 includes two or more mesh covers, which can make the area of ​​a single mesh cover smaller, which is beneficial to improving the structural strength of the mesh cover. For example, Figure 5 and Figure 8 As shown, in one embodiment, a cover shell 23 specifically includes a mesh cover 231; Fig. 9 As shown, in one embodiment, the above-mentioned one cover shell 23 specifically includes two mesh covers 231. The above are only two specific embodiments. In other embodiments, one cover shell 23 may also include a larger number of mesh covers 231, which may be selected and designed according to factors such as the size of the box body 21 of the actual battery pack 2, the number of battery packs 2, and the position and size of the pressure relief valve 22.

[0061] In some embodiments, the battery pack 2 includes two or more pressure relief valves 22, and one cover 23 can protect one, two or more pressure relief valves 22. The battery pack 2 can also include one, two or more covers 23. For example, when the battery pack 2 includes at least two pressure relief valves 22, in one embodiment, one cover 23 is used to protect all the pressure relief valves 22 located on the same box board of the box body 21; in one embodiment, the battery pack 2 includes at least two covers 23 arranged in a one-to-one correspondence with the at least two pressure relief valves 22.

[0062] There are also many options for forming the mesh cover 231 on the cover shell 23. In one embodiment, a through hole is formed on the plate shell 232 of the cover shell 23, and the mesh cover 231 is installed at the position where the through hole is formed on the plate shell 232 of the cover shell 23. In this embodiment, the plate shell 232 and the mesh cover 231 are two independent structures, and the mesh cover 231 is installed through the through hole located in the plate shell 232.

[0063] In one embodiment, the cover shell 23 and the mesh cover 231 are an integrated structure. Specifically, the plate shell 232 of the cover shell 23 itself includes a plurality of small holes, and the plurality of small holes form the mesh cover 231. This solution can improve the structural strength of the cover shell 23.

[0064] In addition, the shape of the outer contour of the mesh cover 231 in the embodiment of the present application can have multiple options. For example, in the above embodiment, the outer contour of the mesh cover 231 is circular as an example. In other embodiments, the outer contour of the mesh cover 231 can also be square, trapezoidal or irregular.

[0065] Please refer to Figure 4 In one embodiment, the end shell 233 of the cover shell 23 facing the bottom plate 213 has an opening 236. In this embodiment, sparks, foreign matter, or plastic melt fluid passing through the mesh cover 231 can flow out of the protection cavity through the opening 236 under the action of gravity, reducing the accumulation of debris in the protection cavity, thereby reducing the risk of the debris blocking the mesh cover 231 or the pressure relief valve 22.

[0066] There are multiple options for forming the above-mentioned opening 236 in the present application. In one embodiment, the above-mentioned opening 236 is a through hole formed in the end shell 233 of the cover shell 23 facing the bottom plate 213, for example, it can be a circular hole, a strip hole or a bent hole, etc.

[0067] In one embodiment, the opening 236 is located at the edge of the end shell 233 facing the side plate 211, so that there is a gap between the end shell 233 of the cover shell 23 and the side plate 211. In other words, the gap between the end shell 233 of the cover shell 23 and the side plate 211 is directly used as the opening 236. This solution can simplify the preparation process of the cover shell 23 and is conducive to simplifying the assembly process of the cover shell 23 and the box body 21. In one embodiment, the gap can be made to pass through the area adjacent to the end shell 233 and the side plate 211.

[0068] The width of the above-mentioned gap is greater than or equal to 2 mm, for example, the width of the above-mentioned gap can be any size such as 2.5 mm, 2.8 mm, 3 mm, 3.5 mm, 4 mm or 5 mm, so that general substances can flow out of the protective cavity through the gap.

[0069] Please refer to Figure 4 In one embodiment, the end shell 233 is an inclined end shell or a curved end shell. Specifically, the end shell 233 and the side plate 211 have an acute angle on the inner side of the protective cavity. The end of the end shell 233 close to the side plate 211 is the first end 2331, and the end away from the end side plate 211 is the second end 2332. The distance between the first end 2331 of the end shell 233 and the bottom plate 213 is smaller than the distance between the second end 2332 of the end shell 233 and the bottom plate 213. The opening 236 is located at the first end 2331 of the end shell 233. In this embodiment, the end shell 233 is equivalent to a guide plate, and the material entering the protective cavity can flow out from the opening 236 more smoothly.

[0070] Fig.10 A schematic diagram of the structure of a battery pack in an embodiment of the present application is shown in FIG. Fig.10 As shown, in one embodiment, the mesh cover 231 includes two layers of cover surfaces 2311, and a cooling core 2312 is disposed between the two layers of cover surfaces 2311. The cooling core 2312 is used to absorb heat. The gas discharged from the pressure relief valve 22 can reduce the temperature to a certain extent, so as to reduce the damage to people or devices outside the battery pack 2 caused by the gas generated by the thermal failure of the battery pack 2.

[0071] There are multiple options for the structure and material selection of the cooling core 2312. In one embodiment, the cooling core 2312 includes a phase change material, which absorbs the heat of the high-temperature gas through the phase change of the phase change material, so as to achieve the cooling purpose in a physical way; in one embodiment, the cooling core 2312 includes magnesium carbonate, which absorbs heat and undergoes a chemical reaction, so as to achieve the cooling purpose in a chemical way.

[0072] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A battery pack, characterized in that: It comprises a box body, a pressure relief valve, a cover shell and a battery cell, wherein the box body has a containing cavity, and the battery cell is arranged in the containing cavity; The pressure relief valve is installed on the box body, the cover shell is located in the accommodating cavity and fixed to the box body, and the cover shell is arranged on the peripheral side of the pressure relief valve; the cover shell includes a mesh cover, and the orthographic projection of the mesh cover on the box plate equipped with the pressure relief valve does not overlap with the orthographic projection of the pressure relief valve on the box plate.

2. The battery pack according to claim 1, characterized in that: The box body includes a top plate, a bottom plate and a side plate, the side plate connects the top plate and the bottom plate, the pressure relief valve is installed on the side plate, and the distance between the edge of the mesh cover facing the bottom plate and the bottom plate is smaller than the distance between the edge of the pressure relief valve facing the bottom plate and the bottom plate.

3. The battery pack according to claim 1, wherein: The box body comprises a top plate, a bottom plate and a side plate, the side plate connects the top plate and the bottom plate, the pressure relief valve is mounted on the side plate, and the end shell of the cover shell facing the bottom plate has an opening.

4. The battery pack according to claim 3, characterized in that: The end of the end shell close to the side plate is the first end, and the end away from the side plate is the second end. The distance between the first end of the end shell and the bottom plate is smaller than the distance between the second end of the end shell and the bottom plate, and the opening is located at the first end of the end shell.

5. The battery pack according to claim 3 or 4, characterized in that: The opening is located at an edge of the end shell facing the side plate, and a gap is provided between the end shell of the cover shell and the side plate.

6. The battery pack according to claim 5, characterized in that: The width of the gap is greater than or equal to 2 mm.

7. The battery pack according to any one of claims 1 to 6, characterized in that: The mesh cover comprises two layers of cover surfaces, and a cooling core is arranged between the two layers of cover surfaces.

8. The battery pack according to claim 7, characterized in that: The cooling core includes phase change material or magnesium carbonate.

9. The battery pack according to any one of claims 1 to 8, characterized in that: The cover shell includes at least two mesh covers.

10. The battery pack according to any one of claims 1 to 9, characterized in that: The cover shell comprises a through hole, and the mesh cover is installed in the through hole of the cover shell.

11. An electrical device, characterized in that: The invention comprises a functional component and a battery pack according to any one of claims 1 to 10, wherein the battery pack is electrically connected to the functional component and is used to supply power to the functional component.

12. An energy storage system, characterized in that: comprising a power converter and a battery pack according to any one of claims 1 to 10, wherein the power converter and the battery pack are electrically connected; The power converter is used to convert the AC power output by the external AC power source into DC power and output it to the battery pack, and / or the power converter is used to convert the DC power output by the battery pack into AC power and output it to a load or a power grid.

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