Battery pack and energy storage system

Abstract

The invention provides a battery pack, which comprises a plurality of battery cells and a box body, the outer wall of the box body is provided with an explosion-proof valve and a flow guide cover, the flow guide cover is fixedly connected with the outer wall, the flow guide cover covers the periphery of the explosion-proof valve, the flow guide cover is provided with one or more air vents, and the air vents are communicated with the explosion-proof valve. The included angle A between the opening direction of at least one of the one or more air vents and the outer wall is larger than or equal to 0 degree and smaller than 90 degrees. And the flow guide cover plays a role in reducing the speed and cooling high-temperature gas, dust and electrolyte released by the battery pack, so that the released high-temperature gas is prevented from impacting the surrounding environment.

Description

Battery pack and energy storage system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on August 18, 2023, with application number 202322239170.2 and application name “A Battery Pack and Energy Storage System”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of energy storage technology, and in particular to a battery pack and an energy storage system. Background Art

[0004] To address global climate change and other issues caused by the extensive use of fossil fuels, countries are actively seeking clean energy alternatives, leading to continued growth in wind and photovoltaic power generation. Due to the unstable and uneven nature of clean energy generation, electrochemical energy storage, with its advantages of high environmental adaptability, rapid response, high power, and high energy density, is expected to become the mainstream energy storage solution of the future. At the same time, this also places higher demands on the safety, cycle life, and other performance characteristics of energy storage products.

[0005] To accommodate large-capacity energy storage applications, multiple single cells are typically connected in series to form a cell, which is then assembled into a battery pack. To ensure the safety of the battery pack, an explosion-proof valve is typically installed on the outer wall. When thermal runaway occurs inside the battery pack, the valve opens, rapidly releasing a large amount of high-temperature, high-velocity gas, which can easily impact and injure nearby people and objects, potentially leading to safety accidents.

[0006] Summary of the Invention

[0007] The present application provides a battery pack, which provides a deflector on the explosion-proof valve to cool down and slow down the high-temperature gas, dust and electrolyte released during thermal runaway of the battery pack, thereby preventing the high-temperature gas, dust and electrolyte released during thermal runaway of the battery pack from impacting the surrounding environment and ensuring the safety of the surrounding environment during thermal runaway of the battery pack.

[0008] In a first aspect, the present application provides a battery pack, which includes a battery cell and a case, wherein the battery cell includes a plurality of battery cells, and an explosion-proof valve and a flow guide cover are provided on the outer wall of the case, wherein the flow guide cover is fixedly connected to the outer wall, and the flow guide cover is provided on the periphery of the explosion-proof valve, and the flow guide cover is provided with one or more vents, and the angle A between the opening direction of at least one of the one or more vents and the outer wall is in the range of 0°≤A<90°. That is, the opening direction of at least one vent on the flow guide cover is not perpendicular to the outer wall, or in other words, there is an inclination angle between the opening direction of at least one of the one or more vents and the outer wall. The opening direction of the vent is a direction perpendicular to the section where the center point of the vent is located. When the thermal runaway of the battery pack causes the explosion-proof valve to open, the high-temperature gas, dust and electrolyte in the battery pack are released from the explosion-proof valve into the air duct. The side wall of the air duct will block the high-temperature gas, causing the high-temperature gas to flow out from the vent of the air duct. The angle A between at least one vent on the air duct and the outer wall is not vertical. Therefore, at least part of the gas will not be directly ejected from the direction perpendicular to the outer wall, which extends the flow path of the gas and changes the injection direction of the gas, thereby cooling and slowing down the high-temperature gas, thereby preventing the high-temperature gas, dust and electrolyte from impacting the environment around the battery pack.

[0009] In one possible implementation, the area of ​​the single vent or the sum of the areas of the multiple vents is greater than or equal to the flow area after the explosion-proof valve is opened, where the flow area is the area through which gas or liquid can flow after the explosion-proof valve is opened. When there is a single vent, the area of ​​the vent is greater than or equal to the area through which gas can flow after the explosion-proof valve is opened. When there are multiple vents, the sum of the areas of the multiple vents is greater than or equal to the area through which gas can flow after the explosion-proof valve is opened. If the area of ​​the vent or the sum of the areas of the multiple vents is smaller than the flow area after the explosion-proof valve is opened, when the battery pack experiences thermal runaway, the high-temperature gas, dust, and electrolyte released through the explosion-proof valve cannot be discharged from the vent of the shroud in a timely manner and may become clogged inside the shroud, reducing the pressure relief effect of the explosion-proof valve. Therefore, to ensure the pressure relief effect of the explosion-proof valve, the area of ​​the single vent or the sum of the areas of the multiple vents should be greater than or equal to the flow area after the explosion-proof valve is opened.

[0010] In one possible implementation, the area of ​​the vent is 1 to 5 times the flow area after the explosion-proof valve is opened. If the area of ​​the vent on the shroud is smaller than the flow area after the explosion-proof valve is opened, the pressure relief effect of the explosion-proof valve will be reduced. If the area of ​​the vent on the shroud is infinitely larger than the flow area after the explosion-proof valve is opened, the cooling and deceleration effect of the shroud on high-temperature gas, dust, and electrolyte will be reduced. Therefore, the area of ​​the vent can be 1 to 5 times the flow area after the explosion-proof valve is opened, achieving a balance between explosion-proof effect and deceleration and cooling effect, which can ensure both the explosion-proof effect of the battery pack and the cooling and deceleration effect of the shroud.

[0011] In one possible implementation, the air duct includes multiple side walls, that is, the air duct is a polyhedron, and at least one of the multiple side walls is provided with at least one air vent. The air duct is a polyhedron, which can expand the internal space of the air duct and accommodate more high-temperature gas, dust and electrolyte. In addition, the design and selection of the number and position of the air vents are more flexible. The air vents can be set on one surface or on multiple surfaces. When there are multiple air vents, the high-temperature gas, dust and electrolyte released from the battery pack are released from multiple vents, dispersing the high-temperature gas, dust and electrolyte, thereby further enhancing the cooling and deceleration effect of the air duct on the high-temperature gas, dust and electrolyte.

[0012] In one possible implementation, the deflector is fixedly connected to the outer wall. Fixing the deflector directly to the outer wall of the battery pack simplifies the installation process, enhances the mechanical strength of the deflector fixed to the battery pack, prevents the deflector from being blown away by the high-speed gas ejected from the explosion-proof valve, and enhances the safety performance of the battery pack.

[0013] In one possible implementation, the deflector is fixedly connected to the explosion-proof valve. Directly fixing the deflector to the explosion-proof valve can enhance the mechanical strength of the deflector, prevent the high-speed gas ejected from the explosion-proof valve from knocking the deflector away, and enhance the mechanical strength of the deflector.

[0014] In one possible implementation, the deflector includes an opening, through which the explosion-proof valve is mounted. The opening of the deflector faces the outer wall of the battery pack, and the outer wall of the battery pack seals the opening of the deflector. When the deflector is assembled to the outer wall of the battery pack, the deflector is directly fastened to the outer wall of the battery pack through the opening and then secured by welding or screws. This simplifies the assembly process and improves assembly efficiency.

[0015] In one possible implementation, there is an inclination angle between the opening direction of the vent of the air deflector and the direction of the opening of the air deflector. Such a design allows the flow direction of the gas ejected from the explosion-proof valve to flow from the opening to the vent, which can change the direction of the high-temperature gas ejected when the battery pack thermally runs away, extend the gas flow path, and further enhance the cooling and deceleration effect on high-temperature gas, dust and electrolyte.

[0016] In one possible implementation, the air deflector includes a first side wall, a second side wall, and a third side wall, wherein the first side wall, the second side wall, and the third side wall are connected in sequence, the first side wall is arranged opposite to the explosion-proof valve and is spaced apart; the third side wall is parallel to the outer wall and is fixedly connected to the outer wall. The surface opposite to the second side wall is the vent of the air deflector, and the surface perpendicular to both the second side wall and the first side wall is the vent of the air deflector. Since the first side wall is arranged opposite to the explosion-proof valve, the first side wall blocks the gas released by the explosion-proof valve, allowing the high-temperature gas to be released from other surfaces (the vent of the air deflector), dispersing the high-temperature gas, preventing the gas from being ejected from the same direction, preventing the high-temperature gas from converging and causing the temperature to be too high in a certain place, and avoiding impact on the environment around the battery pack.

[0017] In one possible implementation, the air deflector includes a first side wall, two second side walls, and two third side walls. The first side wall is arranged opposite to the explosion-proof valve and has a gap therebetween. The two second side walls are arranged opposite to each other and are both connected to the first side wall. The two third side walls are parallel to the outer wall and are respectively connected to the two second side walls. The two third side walls are both fixedly connected to the outer wall. The first side wall and the two second side walls form a receiving cavity, and part of the explosion-proof valve can be located within the receiving cavity. The first side wall, the two second side walls, and the two third side walls are connected in sequence, wherein there is a gap between the two third side walls, which constitutes the opening of the air deflector. The air deflector is disposed on the outer periphery of the explosion-proof valve through the opening, and the two third side walls are located on the peripheral side of the explosion-proof valve. The two surfaces perpendicular to the two second side walls and the one first side wall constitute the vents of the air duct, that is, the air duct is provided with two vents, and the area of ​​the vents can be adjusted and selected according to the distance between the first side wall and the explosion-proof valve. The air duct has a simple structure and low cost, and can improve the safety performance of the battery pack at a lower cost.

[0018] In a possible implementation, a spacing direction between the two second side walls is perpendicular to a spacing direction between the first side wall and the explosion-proof valve.

[0019] In one possible implementation, the air duct includes a fourth side wall, which is connected to the first side wall, and is connected to any one of the two second side walls. The first side wall, the two second side walls, and the fourth side wall form a receiving cavity. The surface opposite to the fourth side wall constitutes the vent of the air duct, and the area of ​​the vent can be adjusted and selected according to the distance between the first side wall and the explosion-proof valve. The air duct has a simple structure and low cost, and can improve the safety performance of the battery pack at a low cost.

[0020] In one possible implementation, the length of the shroud in the direction of extension of the outer wall is greater than or equal to the length of the explosion-proof valve in the direction of extension of the outer wall. When the opening direction of the vent of the shroud is parallel to the outer wall (i.e., the angle A between the opening direction of the vent and the outer wall is 0°), the length of the shroud being greater than or equal to the length of the explosion-proof valve can extend the flow path of the high-temperature gas, effectively reducing the temperature of the high-temperature gas and preventing impact on the surrounding environment.

[0021] In one possible implementation, the projection of the first side wall of the shroud onto the outer wall covers the explosion-proof valve. This design ensures full contact between the first side wall and the gas ejected from the explosion-proof valve, increasing the blocking area and blocking effect of the first side wall, preventing gas from being ejected along the gap between the first side wall and the explosion-proof valve, and enhancing the cooling and deceleration effect of the shroud.

[0022] In one possible implementation, the air deflector includes two fourth sidewalls, which are disposed opposite each other and connected to the first sidewall, which in turn are connected to the second sidewalls. At least one of the sidewalls of the air deflector is provided with a vent. The sidewalls include the first sidewall, the second sidewalls, and the fourth sidewalls. The first sidewall, the second sidewalls, and the fourth sidewalls enclose the accommodating cavity. The air deflector is a hexahedral cavity, which can increase its accommodating space. One of its faces can be provided with an opening, which is positioned around the explosion-proof valve through the opening. Ventilations can be provided on any one or more of the other five faces. When thermal runaway occurs in the battery pack, the explosion-proof valve opens, releasing high-temperature gas, dust, and electrolyte from the battery pack through the vent, controlling the flow of the high-temperature gas, dust, and electrolyte, and further enhancing the cooling and deceleration effect of the air deflector.

[0023] In one possible implementation, the two fourth side walls are parallel and can be arranged opposite each other along the height of the battery pack to block the gas released by the explosion-proof valve, further enhancing the cooling and deceleration effect of the deflector and achieving directional pressure relief.

[0024] In one possible implementation, the two fourth side walls are inclined relative to the outer wall. The two fourth side walls are not perpendicular to the outer wall but are inclined, which helps to better control the flow direction of the high-temperature gas and enhance the cooling and deceleration effect of the deflector.

[0025] In one possible implementation, the two fourth side walls are perpendicular to the outer wall. This arrangement simplifies the design, allows for diverse implementation processes, and is relatively low cost. It improves the cooling and deceleration effects of the air deflector while reducing the structural complexity of the battery pack.

[0026] In one possible implementation, the fourth sidewall is perpendicular to the outer wall. Only one fourth sidewall is provided along the height of the battery pack. The surface opposite the fourth sidewall along the height of the battery pack serves as the vent for the air duct. This vent can face either the ground or the sky. The fourth sidewall, the first sidewall, and the second sidewall block high-temperature gases released from the battery pack, controlling their outflow through the vent to achieve directional pressure relief. Furthermore, the gases released from the air duct are cooled and decelerated, preventing them from impacting the surrounding environment.

[0027] In one possible implementation, the two second side walls are parallel and can be arranged opposite each other along the width of the battery pack to block the gas released by the explosion-proof valve, further enhancing the cooling and deceleration effect of the deflector and achieving directional pressure relief.

[0028] In one possible implementation, the two second side walls are inclined relative to the outer wall. The two second side walls are not perpendicular to the outer wall but are inclined, which helps to better control the flow direction of the high-temperature gas and enhance the cooling and deceleration effect of the deflector.

[0029] In one possible implementation, the first side wall is parallel to the outer wall. When the battery pack experiences thermal runaway, high-temperature gas released from the battery pack directly contacts the first side wall. The first side wall cools and slows down the high-temperature gas, preventing it from being ejected directly from the side of the battery pack and impacting the environment on the side of the battery pack.

[0030] In one possible implementation, there is an inclination angle between the first side wall and the second side wall, so that the gas released from the battery pack directly contacts the two second side walls. The second side wall is inclined relative to the first side wall, which helps to better control the flow direction of the high-temperature gas and enhance the cooling and deceleration effect of the air guide cover.

[0031] In one possible implementation, the two second side walls are perpendicular to the outer wall. This provides a simple structural design, diverse implementation processes, and low cost, while improving the cooling and deceleration effect of the air deflector and reducing the structural complexity of the battery pack.

[0032] In one possible implementation, the air shroud is a hemispherical body comprising a first sidewall and two second sidewalls, the first sidewall being connected to the two second sidewalls, the two second sidewalls being fixedly connected to the outer wall, the first sidewall having an arcuate surface, and one or more vents being provided on the arcuate surface. A hemispherical air shroud can increase its internal space, increasing its capacity to accommodate high-temperature gas, dust, and electrolyte, further enhancing its cooling and deceleration effects on the high-temperature gas, dust, and electrolyte, and improving the safety of the battery pack.

[0033] In one possible implementation, the area of ​​the at least one vent arranged from the center of the curved surface toward the edge of the curved surface gradually increases. That is, the vent located at the center of the first sidewall has the smallest area, allowing the least amount of high-temperature gas, dust, and electrolyte to pass through, thereby minimizing the impact on the environment directly opposite the sidewall of the battery pack casing. Furthermore, the dispersed arrangement of the vents can disperse high-speed gas, reducing the velocity of the high-temperature gas and further reducing its impact range, thereby avoiding impact on the environment surrounding the battery pack.

[0034] Secondly, embodiments of the present application further provide an energy storage system comprising a plurality of the aforementioned battery packs, which are stacked. Assembling multiple battery packs in a stacked manner allows for any number of battery packs to be stacked vertically as needed, facilitating the adjustment of battery capacity and easing installation.

[0035] In combination with a possible implementation of the second aspect, the explosion-proof valves and the air guide covers of the multiple battery packs are all located on the side of the energy storage device. When one of the battery packs experiences thermal runaway, the high-temperature gas, dust and electrolyte released from the battery pack are released to the side of the battery pack, and its thermal runaway will not spread to the battery packs adjacent to the battery pack above and below, thereby ensuring the safety performance of the entire energy storage device.

[0036] Thirdly, embodiments of the present application further provide a battery pack, comprising a housing and a plurality of battery cells within the housing. An explosion-proof valve and a shroud are provided on the outer wall of the housing. The shroud is disposed around the explosion-proof valve. The shroud includes a sidewall disposed opposite the outer wall of the housing, and one or more vents are provided on the sidewall. When thermal runaway occurs in the battery pack, the explosion-proof valve opens, ejecting gas from the battery pack into the shroud. The sidewalls of the shroud cool and decelerate the gas, which is then ejected from the one or more vents, changing its direction of ejection and thereby preventing the high-temperature gas from impacting the surrounding environment of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG1 is a schematic diagram of an application scenario of an energy storage system in an embodiment;

[0038] FIG2 is a schematic diagram of a first structure of a battery pack provided in an embodiment of the present application;

[0039] FIG3 is a schematic structural diagram of a flow guide cover of a battery pack provided in an embodiment of the present application;

[0040] FIG4 is a schematic diagram of the angle between the outer wall of the battery pack case and the opening direction of the vent of the air guide cover provided in an embodiment of the present application;

[0041] FIG5 is a schematic diagram of a second structure of a battery pack provided in an embodiment of the present application;

[0042] FIG6 is a left side view of a battery pack provided in an embodiment of the present application;

[0043] FIG7 is a first cross-sectional view of a battery pack provided in an embodiment of the present application in the z direction;

[0044] FIG8 is a schematic structural diagram of an explosion-proof valve of a battery pack provided in an embodiment of the present application;

[0045] FIG9 is a second cross-sectional view of the battery pack provided in the embodiment of the present application in the z direction;

[0046] FIG10 is a third cross-sectional view of the battery pack provided in the embodiment of the present application in the z direction;

[0047] FIG11 is a fourth cross-sectional view of the battery pack provided in the embodiment of the present application in the z direction;

[0048] FIG12 is a fifth cross-sectional view of the battery pack provided in the embodiment of the present application in the z direction;

[0049] FIG13 is a sixth cross-sectional view of the battery pack provided in the embodiment of the present application in the z direction;

[0050] FIG14 is a seventh cross-sectional view of the battery pack provided in the embodiment of the present application in the z direction;

[0051] FIG15 is an eighth cross-sectional view of the battery pack provided in the embodiment of the present application in the z direction

[0052] FIG16 is a schematic structural diagram of a hemispherical air guide cover of a battery pack provided in an embodiment of the present application;

[0053] FIG17 is a spherical schematic diagram of a hemispherical air guide cover of a battery pack provided in an embodiment of the present application;

[0054] FIG18 is a ninth cross-sectional view of the battery pack provided in the embodiment of the present application in the z direction;

[0055] FIG19 is a tenth cross-sectional view of a battery pack provided in an embodiment of the present application in the z direction;

[0056] FIG20 is a schematic diagram of a test of a battery pack provided in an embodiment of the present application;

[0057] FIG21 is a schematic diagram of a test of a battery pack provided in an embodiment of the present application;

[0058] FIG22 is a diagram showing test results of a battery pack under heating conditions provided in an embodiment of the present application;

[0059] FIG23 is a graph showing test results of a battery pack under overcharge conditions provided by an embodiment of the present application;

[0060] Figure 24 is a schematic diagram of the third clock structure of the battery pack provided in an embodiment of the present application.

[0061] Explanation of the accompanying drawings: 110 - photovoltaic array; 120 - power converter; 130 - power grid; 140 - external load; 150 - energy storage device; 200 (201, 202) - battery pack; 210 - battery cell; 220 - casing; 221 - casing outer wall; 230 - explosion-proof valve; 231 - top cover of explosion-proof valve; 240 - air guide cover; 241 - first side wall; 242 - second side wall; 243 - third side wall; 244 - fourth side wall; 245 - vent; 300 - temperature sensor. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. However, the embodiment embodiments can be implemented in various forms and should not be understood as being limited to the embodiments set forth herein. The same figure marks 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 explained with reference to the accompanying drawings as examples, but changes can be made as needed, and the changes made are all included in the scope of protection of the present application. The drawings in the embodiments of the present application are only used to illustrate the relative position relationship and do not represent the true proportion.

[0063] In the embodiments of this application, the terms "first," "second," etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features.

[0064] It should be noted that the following description sets forth specific details to facilitate understanding of the present application. However, the present application can be implemented in a variety of other ways than those described herein, and those skilled in the art may make similar generalizations without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0065] For ease of understanding, the terms involved in the embodiments of the present application are first explained.

[0066] And / or: It is just a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0067] Multiple: refers to two or more than two.

[0068] The term "connect" should be interpreted broadly. For example, "connect" can mean either a detachable or non-detachable connection, a direct connection, or an indirect connection through an intermediary. The term "fix" should also be interpreted broadly. For example, "fix" can mean either a direct fixation or an indirect fixation through an intermediary.

[0069] The directional terms mentioned in the embodiments of this application, such as "upper," "lower," "front," "back," "left," "right," "inner," "outer," "side," "top," and "bottom," are merely references to directions in the accompanying drawings. These directional terms are intended to better and more clearly illustrate and understand the embodiments of this application, and are not intended to explicitly or implicitly indicate that the devices or components referred to must have a specific orientation, be constructed or operate in a specific orientation, and are therefore not to be construed as limiting the embodiments of this application.

[0070] The battery pack provided in the embodiments of the present application is described below in conjunction with the drawings in the embodiments of the present application.

[0071] The following embodiments of the present application provide a battery pack that can be used in application scenarios such as energy storage systems.

[0072] For example, FIG1 illustrates a schematic diagram of the framework structure of a photovoltaic system. As shown in FIG1 , the photovoltaic system includes a photovoltaic array 110, a power converter 120, an energy storage device 150, and a power grid 130 / external load 140. Specifically, the power converter 120 may integrate a DC / DC conversion circuit and a DC / AC conversion circuit, and the energy storage device 150 may be located between the DC / DC conversion circuit and the DC / AC conversion circuit. The electrical energy generated by the photovoltaic array 110 can be converted into a step-up or step-down voltage by the DC / DC conversion circuit to charge the energy storage device 120. When the electrical energy generated by the photovoltaic array 110 is insufficient to power the power grid 130 / external load 140, the electrical energy stored in the energy storage device 150 can be transmitted to the power grid 130 / external load 140 via the DC / AC conversion circuit within the power converter 120. Furthermore, the energy storage device 150 can also receive power from the power grid 130. The AC power output by the power grid 130 is converted into DC power by the DC / AC conversion circuit and transmitted to the energy storage device 150, thereby charging the energy storage device 150. Typically, to increase the battery capacity of the energy storage device 150, multiple battery packs are stacked. During use, the repeated charging and discharging of the batteries causes electrochemical reactions, which accumulate and release gases into the battery pack. This causes the air pressure inside the battery pack to be higher than the external air pressure. When the pressure reaches a certain level, an explosion can occur, resulting in a safety accident.

[0073] To further enhance the safety of the battery pack, an explosion-proof valve can be installed on the outer wall of the battery pack casing. In household energy storage scenarios, the energy storage device 150 typically stacks multiple battery packs. To ensure the safety of the energy storage device 150, an explosion-proof valve is typically installed on the side of the battery pack. The energy storage device 150 may be placed indoors. When a battery pack experiences thermal runaway, the explosion-proof valve opens, rapidly releasing a large amount of high-temperature gas, dust, and electrolyte, posing a safety hazard to the environment surrounding the energy storage device 150. Experimental testing has shown that the temperature at a distance of 1 meter from the battery pack can reach 200°C. The released high-temperature gas, dust, and electrolyte could cause a high-temperature shock to people near the energy storage device 150, potentially leading to a safety accident. Furthermore, when multiple battery packs are stacked, if one battery pack experiences thermal runaway, the large amount of high-temperature gas, dust, and electrolyte released could impact the explosion-proof valves of adjacent battery packs, damaging those of other battery packs and spreading the heat to other battery packs.

[0074] In order to prevent the high-temperature gas, dust and electrolyte released when the explosion-proof valve 230 is opened from impacting the surrounding people or the environment, an embodiment of the present application provides a battery pack 200. The structure of the battery pack 200 can refer to the structural schematic diagram of the battery pack 200 shown in Figure 2, the structural explosion diagram shown in Figure 5, and the left view of the battery pack 200 shown in Figure 6. The battery pack 200 includes a plurality of battery cells 210 and a box 220. The plurality of battery cells are connected in series, in parallel, or in a mixed (series or parallel) manner to increase the capacity of the battery pack 200 and meet the large-capacity energy storage requirements. An explosion-proof valve 230 and a flow deflector 240 are provided on the outer wall 221 of the housing 220. The explosion-proof valve 230 is in communication with the interior of the housing 220. The flow deflector 240 is fixedly connected to the outer wall 221. The flow deflector 240 is provided around the outer periphery of the explosion-proof valve 230. The flow deflector 240 is provided with one or more vents. The angle A between the opening direction of at least one of the one or more vents and the outer wall facing the explosion-proof valve is in the range of 0°≤A<90°. In other words, the opening direction of at least one vent on the flow deflector is not perpendicular to the outer wall. The angle between the opening direction of the vent and the side wall is a relatively small angle, as shown in Figure 4.

[0075] The opening direction of the vent 245 is perpendicular to the tangent plane where the center point of the vent 245 is located. For example, when the air deflector 240 is a rectangular parallelepiped cavity, referring to the structural schematic diagram of the battery pack 200 shown in FIG2 and the structural schematic diagram of the air deflector 240 shown in FIG3 , in this example, the vent 245 of the air deflector 240 is provided on the surface opposite to the ground (not shown in the figure), and the opening direction of the vent 245 is downward, that is, in the direction of the dotted arrows in FIG2 and FIG3 . When the surface where the vent 245 is located is an arcuate surface, referring to the cross-sectional views of the battery pack 200 in the z direction shown in FIG14 and FIG15 and the structural schematic diagram of the hemispherical air deflector 240 shown in FIG16 , in this example, multiple vents 245 are provided on the spherical surface of the air deflector 240, and the opening direction of the arcuate vent 245 is perpendicular to the tangent plane where the center point of the vent 245 is located, that is, in the direction of the dotted arrows in FIG14 , FIG15 and FIG16 .

[0076] When the explosion-proof valve 230 opens due to thermal runaway of the battery pack 200, the high-temperature gas, dust and electrolyte in the battery pack 200 are released from the explosion-proof valve 230 into the shroud 240. The side walls of the shroud 240 block the high-temperature gas, causing it to flow out from the vents 245 of the shroud 240. The opening direction of at least one vent 245 on the shroud 240 is not perpendicular to the outer wall. Therefore, at least part of the gas will not be directly ejected from the direction perpendicular to the outer wall, extending the gas flow path and changing the gas ejection direction, thereby cooling and slowing down the high-temperature gas, thereby preventing the high-temperature gas, dust and electrolyte from impacting the environment around the battery pack 200.

[0077] In some examples, the area of ​​the vent 245 is greater than or equal to the flow area after the explosion-proof valve 230 is opened, where the flow area is the area through which gas or liquid can flow after the explosion-proof valve 230 is opened. The deflector 240 is provided around the explosion-proof valve 230 to reduce the speed and temperature of the high-temperature gas, dust, and electrolyte released from the battery pack 200. It can also control the outflow of the high-temperature gas, dust, and electrolyte from the vent 245 provided on the deflector 240, controlling the flow direction of the high-temperature gas, dust, electrolyte, and high-temperature dust to avoid impact on people or the environment around the battery pack 200. If the area of ​​the vent 245 on the deflector 240 is smaller than the flow area after the explosion-proof valve 230 is opened, the gas and dust released after the explosion-proof valve 230 is opened will collect inside the deflector 240 and cannot be discharged in time, thereby causing an explosion. Therefore, in order to ensure the explosion-proof effect of the explosion-proof valve 230, the area of ​​the vent 245 on the shroud 240 needs to be greater than or equal to the area through which gas can flow after the explosion-proof valve 230 is opened, so that the gas can be discharged from the battery pack 200 in time after the explosion-proof valve 230 is opened.

[0078] If the area of ​​the vent is infinitely greater than or equal to the area of ​​the explosion-proof valve 230, its cooling and deceleration effect will be reduced. Therefore, in order to ensure the deceleration and cooling effect of the deflector 240 on the gas released after the explosion-proof valve 230 is opened, the area of ​​the vent can be 1 to 5 times the flow area after the explosion-proof valve 230 is opened. For example, the area of ​​the vent on the deflector 240 can be 1 times, 1.5 times, 2 times, 3 times, 3.5 times, 4 times, 4.5 times, 5 times, etc. of the flow area after the explosion-proof valve 230 is opened.

[0079] The shape of the air guide cover 240 in the embodiment of the present application can be selected in many ways. For example, it can be a regular polyhedron, such as a cuboid, a cube, a pentahedron, a hexahedron, etc., or it can be an irregular polyhedron, or it can be a sphere, a cylinder, etc.

[0080] In one embodiment, the deflector 240 includes an opening, and the deflector 240 is provided with the explosion-proof valve 230 through the opening and then fixed by welding or screw connection, etc., the assembly process is simple and efficient, thereby improving assembly efficiency.

[0081] The shroud 240 can be directly fixedly connected to the outer wall of the housing to achieve mechanical fixation between the shroud 240 and the battery pack 200, or it can be directly fixedly connected to the explosion-proof valve 230 to achieve mechanical fixation between the shroud 240 and the battery pack 200. This can enhance the mechanical strength of the shroud 240, prevent the high-speed gas ejected from the explosion-proof valve 230 from knocking the shroud 240 away, and thus enhance the mechanical strength of the shroud 240. The shroud 240 can be connected to the outer wall 221 of the housing 220 or the explosion-proof valve using various methods, such as screw connection, welding, hinged connection, and clamping connection.

[0082] The air deflector 240 provided in the embodiment of the present application may be an integral piece formed by a sheet metal part through a bending process, or may be an assembly formed by welding a plurality of sheet metal parts.

[0083] The material of the air guide cover 240 provided in the embodiment of the present application can be high-strength metal with strong temperature resistance, such as aluminum, stainless steel, sheet metal, etc.

[0084] In one embodiment, the flow guide cover 240 can be a rectangular cavity. Referring to Figures 2, 5 and 6, the explosion-proof valve 230 and the flow guide cover 240 are arranged on the outer wall 221 of the battery pack 200 box 220, and the flow guide cover 240 is arranged on the outer periphery of the explosion-proof valve 230. Referring to the cross-sectional view along the z-direction in FIG. 2 shown in FIG. 7 , the air deflector 240 includes a first sidewall 241, two second sidewalls 242, two third sidewalls 243, and two fourth sidewalls 244. The first sidewall 241 is disposed opposite and spaced from the explosion-proof valve 230 along the length of the battery pack 200 (the y-direction in FIG. 2 ). The two second sidewalls 242 are disposed opposite and connected to the first sidewall 241 along the width of the battery pack 200 (the x-direction in FIG. 2 ). The two third sidewalls 243 are coplanar and connected to the second sidewalls 242. Both third sidewalls 243 are parallel to the first sidewall 241. The two fourth sidewalls 244 are disposed opposite each other along the height of the battery pack 200 (the z-direction in FIG. 2 ). The two fourth sidewalls 244 are connected to the two second sidewalls 242, the first sidewall 241, and the two third sidewalls 243. The two third sidewalls 243 are located around the explosion-proof valve 230. A first side wall 241, two second side walls 242, two fourth side walls 244, and the outer wall 221 of the battery pack 200 housing 220 form a receiving chamber. A portion of the explosion-proof valve 230 that leaks out of the outer wall 221 of the battery pack 200 housing 220 may be located within the receiving chamber, and the two third side walls 243 are fixedly connected to the outer wall 221 of the battery pack 200 housing 220. For example, multiple screw holes may be provided on the outer wall 221 and at positions corresponding to the third side walls 243, and the shroud 240 may be fixed to the outer wall 221 of the housing 220 using screws. Alternatively, the two third side walls 243 may be fixed to the outer wall 221 of the battery pack 200 housing 220 using welding. At least one air vent can be set on at least one of the first side wall 241, the two second side walls 242, the two third side walls 243 and the two fourth side walls 244. When there is one air vent, the area of ​​the air vent is greater than or equal to the area through which gas can flow after the explosion-proof valve 230 is opened. When there are multiple air vents, the sum of the areas of the multiple air vents is greater than or equal to the area through which gas can flow after the explosion-proof valve 230 is opened.

[0085] The embodiments of the present application do not specifically limit the type of explosion-proof valve 230. For example, the explosion-proof valve 230 can be a metal or plastic explosion-proof disc with notches as an explosion-proof element. When a certain pressure is reached, the explosion-proof disc ruptures to release pressure. The explosion-proof valve 230 can also be a waterproof and breathable explosion-proof valve 230. A waterproof and breathable membrane is set inside the explosion-proof valve 230. When the battery pack 200 is in a normal working state, the gas inside the box 220 of the battery pack 200 exchanges gas with the outside through the explosion-proof valve 230 to maintain the air pressure balance inside the battery pack 200. The waterproof and breathable membrane can prevent dust and water droplets from entering the battery pack 200. When thermal runaway occurs inside the battery pack 200, causing the air pressure inside the battery pack 200 to be too high, the explosion-proof valve 230 is in an open state, quickly discharging the gas inside the battery pack 200, thereby playing an explosion-proof role. The explosion-proof valve 230 can also be a spring-loaded explosion-proof valve 230, including a valve body, an elastic component and a protective cover. When the air pressure inside the battery pack 200 rises sharply, the elastic component pushes open the protective cover, and the explosion-proof valve 230 opens to achieve rapid pressure relief.

[0086] Figure 8 shows a simplified schematic diagram of a spring-loaded cylindrical explosion-proof valve 230 after it is opened. When thermal runaway occurs inside the battery pack 200, the top cover 231 of the explosion-proof valve 230 is lifted by the spring, creating a gap between the top cover 231 and the valve body of the explosion-proof valve 230. Gas inside the battery pack 200 is released through this gap. The flow area after the explosion-proof valve 230 is opened is the area of ​​the gap, i.e., S = 2π*R*H, (where S is the flow area after the explosion-proof valve 230 is opened, R is the radius of the bottom surface of the valve body of the explosion-proof valve 230, and H is the distance from the top cover 231 to the top surface of the valve body after the explosion-proof valve 230 is opened).

[0087] It should be understood that the two third side walls 243 can extend in the z-direction or in a direction opposite to the z-direction, as shown in FIG9 and FIG7 , respectively, showing cross-sectional views of the battery pack 200 in the z-direction. If the air guide cover 240 is formed by bending a sheet metal sheet, the two third side walls 243 can be bent either inside or outside the cavity of the air guide cover 240.

[0088] Furthermore, the wall surface of the first side wall 241 may be a plane or a curved surface. The structure thereof is shown in the cross-sectional view of the battery pack 200 in the z direction shown in FIG. 9 .

[0089] When the air deflector 240 is a rectangular parallelepiped cavity, the first sidewall 241 can be parallel to the outer wall 221 of the battery pack 200, or it can be inclined at an angle to the outer wall 221 of the battery pack 200 (i.e., inclined along the y-direction away from the battery pack 200). This can enhance the guiding effect and allow the gas or electrolyte ejected from the explosion-proof valve 230 to change its injection direction more smoothly. For example, the angle between the first sidewall 241 and the outer wall 221 of the battery pack 200 toward the explosion-proof valve 230 is an acute angle, i.e., an inclined angle. Referring to the cross-sectional view of the battery pack 200 along the z-direction shown in FIG10 , the present embodiment does not limit the inclination angle of the first sidewall 241.

[0090] Furthermore, the length of the air deflector 240 in the direction in which the outer wall extends is greater than or equal to the length of the explosion-proof valve 230 in the direction in which the outer wall extends. When the opening direction of the vent of the air deflector 240 is parallel to the outer wall (i.e., the angle A between the opening direction of the vent and the outer wall is 0°), and when the length of the air deflector 240 is greater than or equal to the length of the explosion-proof valve 230, the flow path of the high-temperature gas can be extended, effectively reducing the temperature of the high-temperature gas and preventing impact on the surrounding environment. The projection of the first side wall 241 of the air deflector 240 on the outer wall covers the explosion-proof valve 230. This design allows the first side wall 241 to fully contact the gas ejected from the explosion-proof valve 230, increasing the blocking area and blocking effect of the first side wall 241, preventing the gas from being ejected along the direction of the gap between the first side wall 241 and the explosion-proof valve 230, and enhancing the cooling and deceleration effect of the air deflector 240.

[0091] Similarly, the second sidewall 242 can be perpendicular to the outer wall 221 of the battery pack 200 housing 220, as shown in the cross-sectional views of the battery pack 200 along the z-direction shown in Figures 9-11. The second sidewall 242 can also be non-perpendicular to the outer wall 221 of the battery pack 200 housing 220. As shown in the schematic structural diagram of the battery pack 200 shown in Figure 12, the angle between the second sidewall 242 and the outer wall 221 of the battery pack 200 housing 220 is acute. Of course, the second sidewall 242 and the sidewall of the battery pack 200 housing 220 can be acute. Furthermore, the two second sidewalls 242 can be parallel to each other and perpendicular to the sidewall of the housing 220. Alternatively, the two second sidewalls 242 can be parallel to each other and have an inclination angle with the sidewall of the housing 220, for example, both second sidewalls 242 are inclined along the z-direction, or both second sidewalls 242 are inclined in a direction opposite to the z-direction. 12 is a cross-sectional view of the battery pack 200 in the z direction, in which both second side walls 242 are inclined toward the explosion-proof valve 230. Therefore, the cavity of the shroud 240 has various shapes, which are not limited in this application.

[0092] By controlling the inclination direction of the first side wall 241 and the two second side walls 242 , the injection direction of the high-temperature gas can be better controlled, the cooling and deceleration effect of the air guide cover 240 can be improved, and directional pressure relief can be achieved according to actual needs.

[0093] The number and shape of the vents on the air deflector 240 can be designed and selected in a variety of ways. The vents can be circular, polygonal, or other shapes to expand the ventilation area of ​​the air deflector 240. Any sidewall of the air deflector 240 can be used as a vent, or vents can be provided on the sidewalls of the air deflector 240.

[0094] For example, referring to the cross-sectional view of the battery pack 200 in the middle z direction shown in FIG7 , vents (not shown in the figure) can be provided on or separately from the two second side walls 242 . When the battery pack 200 experiences thermal runaway, the high-temperature gas, dust, and electrolyte inside are released to the outside of the battery pack 200 case 220 along the direction of the arrows in FIG7 . By providing the vents on the two second side walls 242 , the first side wall 241 and the two fourth side walls 244 can play a certain role in blocking the high-temperature gas, dust, and electrolyte or dust, thereby reducing the temperature and flow rate of the gas released from the battery pack 200 and controlling the high-temperature gas, dust, and electrolyte to flow out along the vents on the second side walls 242 , thereby controlling the flow direction of the high-temperature gas, dust, and electrolyte inside the battery pack 200 and preventing the flow direction of the gas released from the battery pack 200 from being too dispersed, thereby causing an impact on the environment or people around the battery pack 200.

[0095] It can be understood that in order to further enhance the cooling and deceleration effect of the air duct 240, a vent can be provided only on the second side wall 242. The remaining side walls of the air duct 240 can block the high-temperature gas, dust and electrolyte, and control the high-temperature gas, dust and electrolyte released by the thermal runaway of the battery pack 200 to flow out from the vent.

[0096] Similarly, vents may be provided on each of the two fourth side walls 244 , or a vent may be provided on only one of the second side walls 242 .

[0097] Similarly, the air deflector 240 may include only a first sidewall 241, a second sidewall 242, two third sidewalls 243, and no fourth sidewall 244. The first sidewall 241, the second sidewall 242, and the third sidewall 243 are sequentially connected, with the first sidewall 241 positioned opposite and spaced from the explosion-proof valve 230; the third sidewall 243 is parallel to the outer wall and fixedly connected to the outer wall. The surface opposite the second sidewall 242 serves as the vent for the air deflector 240, and the surface perpendicular to both the second sidewall 242 and the first sidewall 241 serves as the vent for the air deflector 240. Since the first side wall 241 is arranged opposite to the explosion-proof valve 230, the first side wall 241 blocks the gas released by the explosion-proof valve 230, so that the high-temperature gas is released from other surfaces (the vent of the guide cover 240), disperses the high-temperature gas, avoids the gas from being ejected from the same direction, prevents the high-temperature gas from gathering and causing the temperature to be too high in a certain place, and avoids impacting the environment around the battery pack 200.

[0098] Similarly, the air deflector 240 may include only the first side wall 241, two second side walls 242, and two third side walls 243, but not include the fourth side wall 244, or include only one fourth side wall 244. Referring to the structural schematic diagram of the battery pack 200 shown in FIG2 and the cross-sectional view of the battery pack 200 in the y direction shown in FIG13, the air deflector 240 on the battery pack 200 shown in the figure only includes the first side wall (not shown), two second side walls 242, two third side walls 243, and one fourth side wall 244. The fourth side wall 244 is located above the first side wall 241, the two second side walls 242, and the two third side walls 243 and is connected to the first side wall 241, the two second side walls 242, and the two third side walls 243. The two third side walls 243 are used to fix the air deflector 240 to the outer wall 221 of the box 220 of the battery pack 200. The surface opposite the fourth sidewall 244 is the vent of the shroud 240, which faces the ground. When the battery pack 200 experiences thermal runaway, the sidewalls of the shroud 240 block and cool the gas, allowing high-temperature gas, dust, and electrolyte to escape through the vent in the direction indicated by the arrows in Figure 13, toward the ground. This prevents the high-temperature gas, dust, and electrolyte from impacting the surrounding environment and personnel, providing directional pressure relief.

[0099] It should be understood that the two fourth side walls 244 can be arranged in parallel. There can also be an inclination angle between the two fourth side walls 244 and the outer wall 221, that is, the two fourth side walls 244 are not perpendicular to the outer wall 221, but are in the shape of an inclined plane, which helps to better control the flow direction of the high-temperature gas and enhance the cooling and deceleration effect of the air duct 240. The two fourth side walls 244 can also be arranged perpendicular to the outer wall 221. The two fourth side walls 244 and the outer wall 221 of the box body 220 of the battery pack 200 are perpendicular to each other. The structural design is simple, the implementation process is diverse, and the cost is low. While enhancing the cooling and deceleration effect of the air duct 240, the structural complexity of the battery pack 200 is reduced.

[0100] In one possible implementation, a fourth side wall 244 is perpendicular to the outer wall 221. Only one fourth side wall 244 is provided along the height direction of the battery pack 200. The surface opposite the fourth side wall 244 along the height direction of the battery pack 200 serves as the vent of the air duct 240. This vent can face either the ground or the sky. The fourth side wall 244, the first side wall 241, and the second side wall 242 block the high-temperature gas released from the battery pack 200, controlling the outflow of the high-temperature gas from the vent to achieve directional pressure relief. Furthermore, the gas released from the air duct 240 has been cooled and decelerated, and will not impact the surrounding environment.

[0101] In one embodiment, the flow guide cover 240 can be a hemispherical cavity. Referring to Figure 14, a cross-sectional view of the battery pack 200 in the z direction is shown. The explosion-proof valve 230 and the flow guide cover 240 are located on the side wall of the battery pack 200 box 220, and the flow guide cover 240 is arranged outside the explosion-proof valve 230. The air deflector 240 includes a first side wall 241 and two third side walls 243. The first side wall 241 has an arcuate surface, and the two third side walls 243 are both connected to the first side wall 241. The two third side walls 243 are fixedly connected to the outer wall 221 of the case 220 of the battery pack 200. The two third side walls 243 of the air deflector 240 can be welded to the outer wall 221 of the case 220 by a welding process. Alternatively, multiple screw holes can be provided at corresponding positions on the outer wall 221 of the case 220 and the two third side walls 243, and screws can be used to fix the air deflector 240 to the outer wall 221 of the case 220 of the battery pack 200. Multiple vents can be provided on the first side wall 241 to serve as ventilation for the air deflector 240. The sum of the areas of the multiple vents is greater than or equal to the flow area after the explosion-proof valve 230 is opened.

[0102] When the air deflector 240 is a hemispherical cavity, Figure 16 illustrates an arrangement of the vents on the first sidewall 241, and Figure 17 illustrates a schematic diagram of the spherical surface of the hemispherical air deflector 240. The vents are arranged from the center to the edge of the first sidewall 241, and the area of ​​the vents gradually increases. The vents located in the center of the first sidewall 241 have the smallest area, allowing the least amount of high-temperature gas, dust, and electrolyte to pass through, thereby minimizing the impact on the environment directly opposite the sidewall of the battery pack 200 housing 220. In addition, the dispersed arrangement of the vents can disperse high-speed gas, reduce its velocity, and further reduce its impact range, thereby avoiding impact on the environment surrounding the battery pack 200.

[0103] It should be understood that the two third side walls 243 can extend in a direction toward the explosion-proof valve 230 or in a direction away from the explosion-proof valve 230 , as shown in FIG18 , which is a cross-sectional view of the battery pack 200 in the z direction.

[0104] The air deflector 240 can also be a polyhedral cavity. Referring to the cross-sectional view of the battery pack 200 along the z-direction shown in FIG19 , the air deflector 240 includes four sequentially connected first side walls 241, two third side walls 243, and two fourth side walls 244 (not shown). The two fourth side walls 244 are arranged opposite each other along the z-direction, and the two third side walls 243 are used to be fixedly connected to the outer wall 221 of the box 220 of the battery pack 200. A vent can be provided on at least one of the four first side walls 241 or the two fourth side walls 244, or one of the side walls can be removed and used as the vent of the air deflector 240.

[0105] In order to further enhance the cooling effect of the air guide 240 on high-temperature gas, dust and electrolyte, the side wall of the air guide 240 can be designed as a hollow structure, that is, a flow channel is opened in the air guide 240, and coolant or cold air can flow through the flow channel to cool the high-temperature gas, dust and electrolyte released by the explosion-proof valve 230.

[0106] In order to further enhance the explosion-proof effect of the battery pack 200, each battery cell in the battery cell 210 is also provided with an explosion-proof valve 230. When thermal runaway occurs in the battery cell, the explosion-proof valve 230 of the battery cell and the explosion-proof valve 230 of the battery pack 200 are both opened, releasing the high-temperature gas inside the battery cell to the outside of the box 220 of the battery pack 200, preventing the spread and diffusion of thermal runaway.

[0107] Furthermore, the explosion-proof valve 230 of the battery cell can be oriented toward the explosion-proof valve 230 of the battery pack 200, so that when thermal runaway occurs in the battery cell, the gas released from the battery cell flows directly from the explosion-proof valve 230 of the battery cell to the explosion-proof valve 230 of the battery pack 200. The flow path is shorter, and the high-temperature gas is quickly discharged to prevent heat diffusion from spreading to other battery cells.

[0108] In order to verify the effect of the above-mentioned air deflector 240, a thermal runaway test was carried out on the battery pack 200 equipped with the air deflector 240 and the explosion-proof valve 230. The structure of the bottom surface of the air deflector 240 where the vent is set can be referred to the structural schematic diagram of the battery pack 200 shown in Figure 2 and the cross-sectional view of the battery pack 200 in the y direction shown in Figure 13.

[0109] 1. Arrange the battery pack to be tested and the test equipment

[0110] 20 and 21 , two battery packs 201 and 202 are stacked, with the explosion-proof valve 230 of the battery pack 201 as the center and temperature sensors 300 arranged at heights of 40 cm, 80 cm, and 120 cm at a radius of 1 m. The temperature sensors 300 are arranged on the ground on one side of the explosion-proof valve 230 of the battery pack 201. The temperature sensors 300 are arranged in a fan shape, and temperature sensors 300 are also arranged inside the battery pack 202 below.

[0111] 2. Test Method

[0112] Thermal runaway of the battery pack 201 is triggered by overcharging or heating, and the temperature of the surrounding environment of the battery pack 201 and the battery pack 202 below is collected.

[0113] 3. Test Results

[0114] FIG22 shows the temperature distribution of the surrounding environment of the battery pack 201 when heating triggers thermal runaway of the battery pack 201 , and FIG23 shows the temperature distribution of the surrounding environment of the battery pack 201 when overcharging triggers thermal runaway of the battery pack 201 .

[0115] According to the test results shown in Figure 22, in the heating scenario, when battery pack 201 experienced thermal runaway, the maximum temperature at a height of one meter from battery pack 201 reached 48.9°C, and the maximum ground temperature reached 60°C. According to the test results shown in Figure 23, in the overcharging scenario, when battery pack 201 experienced thermal runaway, the maximum temperature at a height of one meter from battery pack 201 reached 53°C, and the maximum ground temperature reached 72°C. Compared to the battery pack without the deflector 240, which achieved a maximum temperature of 200°C at a height of one meter from battery pack 201, installing the deflector 240 around the explosion-proof valve 230 of battery pack 201 significantly reduced the temperature of the gas released during thermal runaway, effectively reducing the impact on the surrounding environment and effectively preventing safety accidents. Furthermore, there was no blockage within the explosion-proof valve 230 of the battery pack 201 experiencing thermal runaway, indicating that installing the deflector 240 did not affect the pressure relief function of the explosion-proof valve 230. The explosion-proof valve 230 of the battery pack 202 located below the thermal runaway battery pack 201 is functioning normally, indicating that the high-temperature gas, dust, and electrolyte released by the thermal runaway battery pack 201 have not entered the deflector 240 below, and have no effect on the function of the explosion-proof valve 230 of the battery pack 202 below. No electrolyte has penetrated into the interior of the lower battery pack 202, and the maximum temperature of the lower battery pack 202 is 90°C, which has no effect on the function of the lower battery pack 202. Therefore, the installation of a deflector 240 around the explosion-proof valve 230 on the outer wall 221 of the battery pack 201 can effectively reduce the temperature of the gas released by the thermal runaway battery pack 201 and can effectively prevent the thermal runaway from spreading to other battery packs 200, thereby improving the safety performance of the entire energy storage device.

[0116] Based on the same inventive concept, an embodiment of the present application also provides an energy storage system, which includes a plurality of the above-mentioned battery packs 200, wherein the plurality of battery packs 200 are stacked from bottom to top, wherein the outer surface of the bottom wall of the case 220 of one battery pack 200 contacts the outer surface of the top wall of the case 220 of another battery pack 200, and the openings of the plurality of battery packs 200 are all facing the side of the energy storage device. When the battery needs to be replaced or repaired, the battery cell 210 can be directly removed from the side opening, which facilitates the replacement and repair of the battery cell 210. By assembling multiple battery packs 200 in a stacking manner, any number of battery packs 200 can be stacked up and down according to actual needs, which is convenient for increasing or decreasing battery capacity and convenient for installation and operation. The energy storage system provided in the embodiment of the present application stacks multiple battery packs 200, which can realize the upper and lower stacking of any number of battery packs 200 according to actual needs, which is convenient for increasing or decreasing battery capacity and convenient for installation and operation.

[0117] In one embodiment, the explosion-proof valves 230 and air deflectors 240 of multiple battery packs 200 are all facing the side of the energy storage device. When thermal runaway occurs in the battery pack 200, the explosion-proof valves 230 located on the side walls of the box 220 of the battery pack 200 open, and the high-temperature gas, dust and electrolyte inside the battery pack 200 are released from the explosion-proof valves 230 into the air deflector 240. The air deflector 240 cools down and slows down the high-temperature gas, dust and electrolyte released from the battery pack 200, preventing the high-temperature gas, dust and electrolyte from impacting the environment around the energy storage device and avoiding the occurrence of safety accidents.

[0118] Based on the same inventive concept, an embodiment of the present application also provides a battery pack 200. Referring to the schematic structural diagram of the battery pack 200 shown in FIG24 , the battery pack 200 includes a housing 220 and a plurality of battery cells located within the housing 220. An explosion-proof valve and a flow deflector 240 are provided on the outer wall of the housing 220. The flow deflector 240 is disposed around the explosion-proof valve. The flow deflector 240 includes a side wall disposed opposite the outer wall of the housing 220, and one or more vents 245 are provided on the side wall. When thermal runaway occurs in the battery pack 200, the explosion-proof valve opens, ejecting gas from the battery pack 200 into the interior of the flow deflector 240. The side walls of the flow deflector 240 cool and decelerate the gas. The gas is then ejected from the one or more vents 245, changing its direction of ejection and thereby preventing the high-temperature gas from impacting the surrounding environment of the battery pack 200.

[0119] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A battery pack, characterized in that: The battery pack comprises a box body and a plurality of battery cells located in the box body, an explosion-proof valve and a flow guide cover are arranged on the outer wall of the box body, and the flow guide cover is arranged on the outer periphery of the explosion-proof valve; The air guide cover is provided with one or more vents, and the range of the angle A between the opening direction of at least one of the one or more vents and the outer wall is 0°≤A<90°.

2. The battery pack according to claim 1, characterized in that: The area of ​​the one vent or the sum of the areas of the multiple vents is greater than or equal to the flow area after the explosion-proof valve is opened, wherein the flow area is the area through which gas can flow after the explosion-proof valve is opened.

3. The battery pack according to claim 2, characterized in that: The area of ​​the one vent or the sum of the areas of the multiple vents is 1 to 5 times the flow area after the explosion-proof valve is opened.

4. The battery pack according to claim 1, characterized in that: The air guide cover includes a plurality of side walls, and at least one of the plurality of side walls is provided with one or more vents.

5. The battery pack according to any one of claims 1 to 4, characterized in that: The air guide cover is fixedly connected to the outer wall.

6. The battery pack according to any one of claims 1 to 4, characterized in that: The flow guide cover is fixedly connected to the explosion-proof valve.

7. The battery pack according to claim 4, characterized in that: The deflector comprises a first side wall, a second side wall and a third side wall, the first side wall, the second side wall and the third side wall are connected in sequence, and the explosion-proof valve is arranged oppositely and has a gap; The third side wall is parallel to the outer wall, and the third side wall is fixedly connected to the outer wall.

8. The battery pack according to claim 4, characterized in that: The deflector comprises a first side wall, two second side walls and two third side walls, the first side wall is arranged opposite to the explosion-proof valve and has a gap, the two second side walls are arranged opposite to each other, and the two second side walls are both connected to the first side wall; The two third side walls are parallel to the outer wall, the two third side walls are connected to the two second side walls respectively, and the two third side walls are fixedly connected to the outer wall.

9. The battery pack according to claim 8, characterized in that: The spacing direction of the two second side walls is perpendicular to the spacing direction between the first side wall and the explosion-proof valve.

10. The battery pack according to claim 8 or 9, characterized in that: The air deflector includes a fourth side wall, the fourth side wall is connected to the first side wall, and the fourth side wall is connected to any one of the two second side walls.

11. The battery pack according to claim 10, characterized in that: The length of the air guide cover in the extending direction of the outer wall is greater than or equal to the length of the explosion-proof valve in the extending direction of the outer wall.

12. The battery pack according to claim 10, characterized in that: The projection of the one first side wall on the outer wall covers the explosion-proof valve.

13. The battery pack according to claim 8 or 9, characterized in that: The air guide cover comprises two fourth side walls, the two fourth side walls are arranged opposite to each other, the two fourth side walls are both connected to the one first side wall, and the two fourth side walls are both connected to the two second side walls; At least one of the side walls of the air deflector is provided with the one or more vents, and the side walls include the one first side wall, the two second side walls and the two fourth side walls.

14. The battery pack according to claim 13, characterized in that: The two fourth side walls are parallel.

15. The battery pack according to claim 13 or 14, characterized in that: The two fourth side walls are both perpendicular to the outer wall.

16. The battery pack according to claim 10, characterized in that: The fourth side wall is perpendicular to the outer wall.

17. The battery pack according to any one of claims 7 to 14, characterized in that: The one first side wall is parallel to the outer wall.

18. The battery pack according to any one of claims 1 to 6, characterized in that: The air deflector is a hemisphere, which includes a first side wall and two second side walls. The first side wall is connected to the two second side walls, and the two second side walls are fixedly connected to the outer wall. The wall surface of the first side wall is an arcuate surface, and the vent is at least one vent arranged on the arcuate surface.

19. The battery pack according to claim 18, characterized in that: The area of ​​the at least one vent arranged along the center of the arc-shaped surface toward the edge of the arc-shaped surface gradually increases.

20. An energy storage device, characterized in that: The energy storage system comprises a plurality of battery packs as described in any one of claims 1 to 19, wherein the plurality of battery packs are stacked.

21. The energy storage device according to claim 20, characterized in that: The explosion-proof valves of the plurality of battery packs and the flow guide cover are all located on the side of the energy storage device.

22. A battery pack, characterized in that: The battery pack includes a box body and a plurality of battery cells located in the box body. An explosion-proof valve and a flow guide cover are provided on the outer wall of the box body. The flow guide cover is provided around the explosion-proof valve. The flow guide cover includes a side wall arranged opposite to the outer wall of the box body, and one or more vents are provided on the side wall.

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