Lower box, battery box and battery cabinet

Abstract

The present application provides a lower box, a battery box and a battery cabinet, which have high heat dissipation efficiency and grouping efficiency, and low cost. The battery cabinet includes the battery box, which includes the lower box and multiple battery modules, in which: the bottom plate includes an upper surface, a first inlet, a second inlet and an outlet, the upper surface includes multiple module installation areas, which are respectively used to install multiple battery modules, the first inlet and the second inlet are respectively located at opposite ends of the bottom plate, the multiple module installation areas are located between the two ends, the outlet is located between two of the module installation areas, and the bottom plate is formed with a first air duct and a second air duct extending from the first inlet and the second inlet to the outlet respectively; the hood is located above the bottom plate and is sealed with the bottom plate, and an air outlet duct is formed in the hood, the air outlet duct includes an air inlet connected to the outlet and at least one air outlet located on the side of the battery box, and the top of the air outlet duct is downward from the air outlet to the direction away from the air outlet.

Description

Technical Field

[0001] The present application relates to the technical field of thermal management of energy storage batteries, and in particular to a lower box, a battery box and a battery cabinet. Background Art

[0002] In recent years, lithium battery energy storage systems have developed rapidly and are still developing at a relatively high speed towards a larger market. As the market continues to expand, the requirements for energy storage systems are becoming clearer and higher. Among them, high reliability, long life, and high volume grouping efficiency are among the most core requirements.

[0003] Apart from standard designs and considerations such as electrical safety design and material life, the key factor that most affects the reliability and life of the battery cell is the thermal management design. Reasonable thermal management design can ensure that the battery cell is at a suitable operating temperature to achieve a long life. At the same time, it can also reduce the additional heat dissipation space set up during grouping, effectively improving the grouping efficiency, especially for the currently widely used container energy storage system. The internal dimensions of the standard 20-foot and 40-foot containers are fixed. Only a more compact volume design can accommodate more energy in a limited space, so as to reduce costs and improve competitiveness. Summary of the invention

[0004] One object of the present application is to provide a lower box for a battery box, which has high heat dissipation efficiency and grouping efficiency and low cost.

[0005] A lower box body for achieving the above purpose is used for a battery box, the battery box includes a plurality of battery modules, the lower box body includes a bottom plate and an air hood, the bottom plate includes an upper surface, a first inlet, a second inlet and an outlet, the upper surface includes a plurality of module mounting areas, respectively used to mount the plurality of battery modules, the first inlet and the second inlet are respectively located at opposite ends of the bottom plate, the plurality of module mounting areas are located between the two ends, the outlet is located between two of the module mounting areas, a first air duct and a second air duct are formed in the bottom plate, the first air duct and the second air duct extend from the first inlet and the second inlet to the outlet respectively; the air hood is located above the bottom plate and is sealed with the bottom plate, an air outlet duct is formed in the air hood, the air outlet duct includes an air inlet and at least one air outlet, the air inlet is connected to the outlet, the air outlet is located on the side of the battery box, and the top of the air outlet duct tends to descend from the air outlet to the direction away from the air outlet.

[0006] In one or more embodiments of the lower box, the bottom plate further includes a partition for separating the first air duct and the second air duct.

[0007] In one or more embodiments of the lower box, a first guide surface and a second guide surface are respectively provided on both sides of the partition, and the first guide surface and the second guide surface are respectively used to guide the airflow in the first air duct and the second air duct to the outlet.

[0008] In one or more embodiments of the lower box, the number of the module installation areas on both sides of the outlet is equal.

[0009] In one or more embodiments of the lower box, the top of the air outlet duct includes an inclined curved surface or a flat surface.

[0010] In one or more embodiments of the lower box body, the lower box body further includes a connecting beam, the connecting beam is arranged above the bottom plate, and the wind shield is connected to the bottom plate through the connecting beam.

[0011] In one or more embodiments of the lower box body, the bottom plate includes an upper plate, a lower plate and a plurality of connecting plates, the upper plate and the lower plate are opposite to each other, the connecting plate connects the upper plate and the lower plate, and a plurality of the first air ducts and a plurality of the second air ducts are formed between the upper plate, the lower plate and the plurality of connecting plates.

[0012] In one or more embodiments of the lower box, the upper plate, the lower plate and the plurality of connecting plates are formed by extrusion of aluminum alloy.

[0013] The lower box body exchanges heat at the bottom of the battery module, allowing cold air to flow in from both ends of the bottom plate and out from the middle, which can shorten the heat exchange path, improve the uniformity of air volume, improve heat exchange efficiency, and reduce the temperature difference between battery cells. There is no need to set gaps between battery cells, which can shorten the length of the battery module. Except for the two rows of battery modules adjacent to the wind cover, the gaps between other adjacent battery modules are small, and the gaps between the battery modules and the sides of the battery box are also small, so that a large number of battery modules can be arranged in the battery box, which greatly improves the volume grouping efficiency and the internal energy can reach liquid The level of the cold battery box; by forming a closed heat dissipation duct between the first inlet and the second inlet of the bottom plate and the exhaust port of the wind hood, the air volume loss can be reduced and the heat exchange efficiency can be further improved; by setting the outlet duct above the outlets of the first duct and the second duct, and setting the exhaust port at a higher position of the outlet duct, a cooling cycle can be formed through natural convection, so that there is no need to set up an additional fan to provide suction, which can reduce power loss, reduce noise, reduce failure rate, improve system reliability, simplify the structure of the battery box, reduce the complexity of the control system, and reduce manufacturing and maintenance costs. The lower box has a simple structure, reliable strength, and is easy to process, manufacture and assemble.

[0014] Another object of the present application is to provide a battery box with high heat dissipation efficiency and grouping efficiency and low cost.

[0015] A battery box for achieving the above purpose includes the aforementioned lower box body.

[0016] In one or more embodiments of the battery box, the battery box further includes a cover plate and a panel assembly, the cover plate is opposite to the bottom plate, the panel assembly is installed on one side surface of the battery box, and the remaining side surfaces of the battery box are open structures.

[0017] In one or more embodiments of the battery box, one of the exhaust vents is located on a side of the battery box where the panel assembly is installed, and the panel assembly includes a heat dissipation through hole, which is connected to the exhaust vent.

[0018] In one or more embodiments of the battery box, the battery box is used to be installed in a battery cabinet, the battery cabinet includes a guide structure, and the lower box body also includes a mounting beam, the mounting beam is arranged on the bottom plate, and the mounting beam is used to be movably connected to the guide structure, thereby providing guidance for the installation of the battery box and for improving the strength of the battery box.

[0019] Another object of the present application is to provide a battery cabinet having high heat dissipation efficiency and grouping efficiency and low cost.

[0020] A battery cabinet for achieving the above-mentioned purpose includes the aforementioned battery box.

[0021] By adopting the lower box body, the battery cabinet and battery box can achieve higher heat dissipation efficiency by utilizing less heat dissipation space, greatly improve the volume grouping efficiency, and do not need to set up an additional fan, thereby reducing power loss, reducing noise, reducing failure rate, improving system reliability, reducing the complexity of the control system, and reducing manufacturing and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other features, properties and advantages of the present application will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0023] Figure 1 is a perspective schematic diagram of a battery box according to one embodiment.

[0024] Figure 2 is an exploded schematic diagram of a battery box according to one embodiment.

[0025] Figure 3 It is a three-dimensional schematic diagram of a lower box according to one embodiment.

[0026] Figure 4 It is a schematic diagram of an exploded view of a lower box according to one embodiment.

[0027] Figure 5 yes Figure 4 Partial schematic diagram at point A in the middle.

[0028] Figure 6 yes Figure 4 A partial schematic diagram of point B in the middle.

[0029] Figure 7 and Figure 8 is a schematic diagram of gas flow in a battery box according to one embodiment. DETAILED DESCRIPTION

[0030] The following discloses a variety of different implementation methods or embodiments of the subject technical solution. To simplify the disclosure, specific examples of each element and arrangement are described below. Of course, these are only examples and are not intended to limit the scope of protection of the present application. It should be noted that the drawings are only examples, which are not drawn according to the conditions of equal proportions, and should not be used to limit the scope of protection actually required by the present application. In addition, certain features, structures or characteristics in one or more embodiments of the present application may be appropriately combined.

[0031] The battery cabinet of the energy storage system is provided with a battery box, and multiple battery modules are provided in the battery box. The temperature of the battery cells of the battery modules will rise during operation. In order to ensure that the battery cells are at a suitable operating temperature, the battery cells in the battery box need to be cooled. The inventor studied a variety of cooling solutions in the process of completing the present invention:

[0032] (1) One solution is to set heat dissipation holes in the battery box body, and the cold air is blown around the battery box. The fan in front of the battery box draws the cold air into the box body through the heat dissipation holes, and the cold air takes out the heat through the side of the battery cell. This solution is simple, but there is a large gap between the box body and the battery cell, resulting in a low volume grouping efficiency.

[0033] (2) Another solution is to set intervals between cells to form air ducts between cells to remove heat. However, this solution increases the length of the module, resulting in increased space in the length direction. This greatly affects the efficiency of cell grouping, especially when the internal width is given, such as in a container.

[0034] In addition, the above solutions (1) and (2) both have problems such as poor air duct sealing and serious waste of air volume, resulting in very little air intake in the middle of the battery box. Therefore, they are only applicable to two rows of modules and cannot further expand the number of modules to improve efficiency. Moreover, they all have front air outlet, and it is necessary to add a fan to drive the hot air at the rear to exit forward. The heat exchange path is long, and the cold air gradually heats up during the heat exchange process, resulting in a decrease in heat exchange capacity. The problem of excessive temperature difference between the front and rear is prone to occur. In addition, the operation noise of the fan is loud, the power loss is large, and the failure rate is high, which affects the reliability of the system, increases the complexity of the control system, and increases the manufacturing and maintenance costs.

[0035] (3) Another solution is to design a liquid cooling plate that fits tightly against the bottom of the battery cell. The heat of the battery cell can be removed by the coolant, which can greatly reduce the gap between modules or battery cells and improve the volume grouping efficiency. However, this solution has problems such as high cost of the liquid cooling system and risk of leakage in the pipeline.

[0036] To solve the above problems, a battery cabinet (not shown) according to one embodiment of the present application adopts the following Figures 1 to 8 The battery box 1 shown includes a cover plate 2, a lower box body 3, a panel assembly 4, a panel bracket 5 and a plurality of battery modules 6.

[0037] The lower box body 3 includes a bottom plate 7 and a wind shield 8. A plurality of battery modules 6 are mounted on the bottom plate 7 by bolts, bonding, or other means, and are arranged on the bottom plate along a first direction X. The panel bracket 5 is mounted on the bottom plate 7 and the battery module 6 by bolts or other means. The panel assembly 4 is mounted on the panel bracket 5 by bolts or other means. The panel assembly 4 is used to provide electrical components related to the operation of the battery module 6 and is electrically connected to the battery module 6. The cover plate 2 is opposite to the bottom plate 7, and the cover plate 2 is mounted on the battery module 6 and the panel assembly 4 by rivets, bonding, or other means.

[0038] The panel assembly 4 is installed on one of the side surfaces of the battery box 1, and the other three sides of the battery box 1 are open structures, that is, no side panels are set on the other three sides, thereby simplifying the structure of the battery box 1, facilitating manufacturing and installation, reducing costs, and facilitating heat dissipation of the battery module 6.

[0039] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or a fluid connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0040] Continue to refer to Figures 1 to 8The bottom plate 7 includes an upper plate 701 , a lower plate 702 , a plurality of connecting plates 703 , a first inlet 73 , a second inlet 74 and an outlet 75 .

[0041] The upper surface 704 of the upper plate 701 includes a plurality of module mounting areas 705, each for mounting a plurality of battery modules 6. The first inlet 74 and the second inlet 75 are respectively located at opposite ends of the bottom plate 7 in the first direction X, namely, the first end 76 and the second end 77. The outlet 75 is located between the first end 76 and the second end 77, and between two of the module mounting areas 705.

[0042] The outlet 75 is located in the middle of the bottom plate 7 in the first direction X, for example, Figures 1 to 8 In the illustrated embodiment, the battery box 1 includes four battery modules 6, and there are two battery modules 6 on each side of the first direction X of the outlet 75, that is, the number of module mounting areas 705 on both sides of the first direction X of the outlet 75 is equal; in other embodiments, the battery box 1 includes more than four or less than four battery modules 6, and when the battery box 1 includes an odd number of battery modules 6, the number of battery modules 6 on one side of the first direction X of the outlet 75 is one more than the number of battery modules 6 on the other side, that is, the number of module mounting areas 705 on one side of the first direction X of the outlet 75 is one more than the number of module mounting areas 705 on the other side.

[0043] In the description of the present application, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present application.

[0044] Continue to refer to Figures 1 to 8 The upper plate 701 and the lower plate 702 are opposite to each other, and the connecting plate 703 connects the upper plate 701 and the lower plate 702. The first air duct 71 and the second air duct 72 are formed between the upper plate 701, the lower plate 702 and the plurality of connecting plates 703. The first air duct 71 extends from the first inlet 73 to the outlet 75, and passes under the two battery modules 6 located between the first end 76 and the outlet 75. The second air duct 72 extends from the second inlet 74 to the outlet 75, and passes under the two battery modules 6 located between the second end 77 and the outlet 75.

[0045] The upper plate 701, the lower plate 702 and the plurality of connecting plates 703 form a plurality of parallel first air ducts 71 and a plurality of parallel second air ducts 72 in the bottom plate 7, i.e., a heat dissipation grille structure. At least one first air duct 71 or a second air duct 72 passes under each battery cell 61 of the plurality of battery modules 6, thereby increasing the strength and heat exchange area of ​​the bottom plate 7 and improving the heat exchange efficiency.

[0046] Optionally, the upper plate 701, the lower plate 702 and the plurality of connecting plates 703 are made of aluminum alloy and are integrally formed through an extrusion process, thereby having good thermal conductivity and high strength, and having no internal joints, thereby forming a straight and smooth first air duct 71 and a second air duct 72, reducing air flow resistance, avoiding wind speed attenuation, and having good sealing properties, thereby reducing air volume loss and improving heat dissipation efficiency.

[0047] In other embodiments, the upper plate 701, the lower plate 702 and the plurality of connecting plates 703 are assembled together by welding, snapping or other means, or the first air duct 71 and the second air duct 72 are formed by machining holes in the bottom plate 7, and so on.

[0048] Reference Figures 4 to 7 The bottom plate 7 also includes a partition 78, which is installed below the outlet 75 by snap-fitting or other means. The partition 78 is used to separate the first air duct 71 and the second air duct 72 to avoid airflow collision in the first air duct 71 and the second air duct 72.

[0049] The partition 78 is provided with a first guide surface 781 and a second guide surface 782 on both sides opposite to the first air duct 71 and the second air duct 72, respectively, for guiding the airflow in the first air duct 71 and the second air duct 72 from the horizontal direction to the vertical direction, so as to flow out to the upper outlet 75. The first guide surface 781 and the second guide surface 782 are smooth curved surfaces, such as arc surfaces, so that the direction of the airflow can be smoothly changed to reduce the impact on the airflow and avoid wind speed reduction or backflow.

[0050] Reference Figures 2 to 8 The hood 8 is located above the bottom plate 7 and is sealed with the bottom plate 7. An air outlet duct 80 is formed in the hood 8, and the air outlet duct 80 includes an air inlet 801 and an air outlet 802. The air inlet 801 is connected to the outlet 75 of the bottom plate 7, and the air outlet 802 is located on the side of the battery box 1. For example, the two air outlets 802 are respectively located on the first side 11 and the second side 12 of the battery box 1. The first side 11 and the second side 12 are opposite to each other and are respectively located on both sides of the second direction Y, and the second direction Y is perpendicular to the first direction X.

[0051] The top 803 of the air outlet duct 80 shows a downward trend from the exhaust port 802 to the direction away from the exhaust port 802, that is, the highest point of the top 803 is located at the exhaust port 802 or close to the exhaust port 802, and the lowest point of the top 803 is located far away from the exhaust port 802, so that the hot air at a lower position in the air outlet duct 80 can spontaneously flow along the top 803 of the air outlet duct 80 to the higher exhaust port 802 under the effect of its own buoyancy, and then be discharged from the side of the battery box 1.

[0052] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "sealed", "enclosed" and the like refer to being airtight or allowing only a small amount of gas leakage.

[0053] Reference Figures 3 to 8 The top 803 of the air outlet duct 80 includes two opposite slopes 804, and the two slopes 804 form an approximately V-shape in the second direction Y. The bottom end 805 of each slope 804 is located in the middle of the air outlet duct 80 in the second direction Y, and the top end 806 of each slope 804 is located at one of the exhaust ports 802 or close to the exhaust port 802, thereby simplifying the structure of the air outlet duct 80 to facilitate processing and manufacturing and reduce costs. The top 803 is relatively flat, which can reduce the air flow resistance in the air outlet duct 80, avoid wind speed attenuation, and improve heat dissipation efficiency.

[0054] In other embodiments, the air outlet duct 80 only includes one exhaust port 802, for example, located on the first side 11, and the top of the air outlet duct 80 includes a slope 804, the bottom end 805 of the slope is located at the second side 12 of the battery box 1 or close to the second side 12, and the top end 806 of the slope is located at the exhaust port 802 or close to the exhaust port 802, thereby simplifying the structure of the air outlet duct 80 to facilitate processing and manufacturing and reduce costs, and the top 803 is relatively flat, which can reduce the air flow resistance in the air outlet duct 80, avoid wind speed attenuation, and improve heat dissipation efficiency.

[0055] In some other embodiments, the top 803 of the air outlet duct 80 includes other inclined surfaces, such as an inclined curved surface, or multiple planes with different slopes, etc.

[0056] Reference Figure 1 , Figure 2 and Figure 8 The first side surface 11 is located on the side of the battery box 1 where the panel assembly 4 is installed, that is, on the front side of the battery cabinet. The panel assembly 4 is provided with a heat dissipation through hole 41 communicated with the exhaust port 802 to utilize the existing operation and maintenance space on the side of the panel assembly 4 for heat dissipation, thereby reducing the heat dissipation space on the left and right sides of the battery cabinet and shortening the distance between adjacent battery cabinets to arrange more energy in a limited space.

[0057] Optionally, the wind hood 8 is made of metal material and manufactured through sheet metal processing, or the wind hood 8 is made of plastic material and is integrally formed through injection molding, extrusion, or other processes to facilitate processing and manufacturing. The inner surface of the wind hood 8 is relatively flat, unobstructed, and has a natural transition, which can reduce the air flow resistance in the air outlet duct 80 and avoid wind speed attenuation. It also has good sealing properties, which can reduce air volume loss, thereby improving heat dissipation efficiency.

[0058] Reference Figures 3 to 7The lower box body 3 further includes a plurality of connecting beams 9, for example, the connecting beams 9 are elongated rectangular tubes, which are arranged above the bottom plate 7, and a connecting cavity 90 is enclosed between the plurality of connecting beams 9. The bottom of the hood 8 is sealedly connected to the bottom plate 7 through the connecting beams 9, for example, by bonding, or by bolting and setting a sealing gasket between the mounting mating surfaces, etc. The air inlet 801 of the hood 8 and the outlet 75 of the bottom plate 7 are connected through the connecting cavity 90, so that the area of ​​the mounting mating surface can be reduced, so as to facilitate installation and ensure sealing, so that a closed heat dissipation air duct is formed between the first inlet 73, the second inlet 74 of the bottom plate 7 and the air outlet 802 of the hood 8, so as to reduce the air volume loss and improve the heat dissipation efficiency, and the strength of the bottom plate 7 and the hood 8 can be strengthened by the connecting beams 9, and the structure is simple and reliable.

[0059] The heat dissipation process of the battery box 1 is described below in conjunction with an embodiment:

[0060] Reference Figure 7 and Figure 8 When the temperature of the battery cell 61 of the battery module 6 rises, the heat of the battery cell 61 is transferred to the bottom plate 7, the air cover 8 and the air inside thereof by heat conduction. The hot air floats up in the air outlet duct 80 and flows along the top 803 of the air outlet duct 80 to the air outlet 802 located at a high position, and then is discharged from the side of the battery box 1. The cooler air outside the battery box 1 flows from the two ends of the bottom plate 7 to the middle part of the bottom plate 7 along the first air duct 71 and the second air duct 72 under the action of convection, and is discharged from the plurality of battery boxes 1. The air flows under each battery cell 61 of the module 6, thereby taking away the heat conducted from the battery cell 61 to the base plate 7. The air is heated during the heat exchange process, and then, under the guidance of the first guide surface 781 and the second guide surface 782 and its own floating effect, it flows to the air outlet duct 80 through the outlet 75, and then flows to the exhaust port 802 along the top 803 of the air outlet duct 80, and is discharged from the side of the battery box 1, so that a cooling cycle can be formed through natural convection, thereby effectively dissipating the heat of the battery module 6.

[0061] The lower box body 3 performs heat exchange at the bottom of the battery module 6, so that cold air flows in from both ends of the bottom plate 7 and flows out from the middle, which can shorten the heat exchange path, improve the uniformity of air volume, improve the heat exchange efficiency, reduce the temperature difference between the battery cells 61, and do not need to set gaps between the battery cells 61, which can shorten the length of the battery module 6. Except for the two rows of battery modules 6 adjacent to the wind cover 8, the gaps between other adjacent battery modules 6 are small, and the gaps between the battery modules 6 and the sides of the battery box 1 are also small, so that a large number of battery modules 6 can be set in the battery box 1, which greatly improves the volume grouping efficiency, and the internal energy can reach the liquid-cooled battery box. level; by forming a closed heat dissipation duct between the first inlet 73, the second inlet 74 of the bottom plate 7 and the exhaust port 802 of the wind hood 8, the air volume loss can be reduced and the heat exchange efficiency can be further improved; by setting the outlet duct 80 above the outlet 75 of the first duct 71 and the second duct 72, and setting the exhaust port 802 at a higher position of the outlet duct 80, a cooling cycle can be formed by natural convection, so that there is no need to set up an additional fan to provide suction, which can reduce power loss, reduce noise, reduce failure rate, improve system reliability, simplify the structure of the battery box 1, reduce the complexity of the control system, and reduce manufacturing and maintenance costs. The lower box body 3 has a simple structure, reliable strength, and is easy to process, manufacture and assemble.

[0062] By adopting the lower box body 3, the battery cabinet and battery box 1 can achieve higher heat dissipation efficiency by utilizing less heat dissipation space, greatly improve the volume grouping efficiency, and do not need to set up an additional fan, thereby reducing power loss, reducing noise, reducing failure rate, improving system reliability, reducing the complexity of the control system, and reducing manufacturing and maintenance costs.

[0063] Reference Figures 1 to 7 The lower box body 3 also includes two mounting beams 10, which are respectively mounted on the first end 76 and the second end 77 of the bottom plate 7 and are perpendicular to the first side 11 where the panel assembly 4 is located. The mounting beam 10 includes a main body 101, a guide portion 102 and a hoisting portion 103. The main body 101 is in the shape of a rectangular tube, which is used to be mounted on the bottom plate 7 and support the guide portion 102. The guide portion 102 is in the shape of an elongated plate, which is used to be movably connected to a guide structure (not shown) in the battery cabinet, thereby providing a guide for the installation of the battery box 1. The hoisting portion 103 is used to connect a lifting tool, for example, the hoisting portion 103 is a lifting hole set on the guide portion 102. The mounting beam 10 can improve the installation efficiency of the battery box 1 and further improve the overall strength of the battery box 1, and has a simple structure, is easy to process and manufacture, and has a low cost.

[0064] Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application, and any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, any modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application shall fall within the scope of protection defined by the claims of the present application.

Claims

1. The lower box is used for a battery box, wherein the battery box includes a plurality of battery modules, characterized in that: The lower box body comprises: A bottom plate, comprising an upper surface, a first inlet, a second inlet and an outlet, wherein the upper surface comprises a plurality of module mounting areas, respectively used to mount the plurality of battery modules, the first inlet and the second inlet are respectively located at opposite ends of the bottom plate, the plurality of module mounting areas are located between the two ends, the outlet is located between two of the module mounting areas, a first air duct and a second air duct are formed in the bottom plate, the first air duct and the second air duct extend from the first inlet and the second inlet to the outlet respectively; and A hood is located above the bottom plate and is sealed with the bottom plate, an air outlet duct is formed in the hood, the air outlet duct includes an air inlet and at least one air outlet, the air inlet is connected to the outlet, the air outlet is located on the side of the battery box, and the top of the air outlet duct is downward from the air outlet to the direction away from the air outlet; The lower box body further comprises a connecting beam, which is arranged above the bottom plate, and the wind shield is connected to the bottom plate through the connecting beam; the connecting beams enclose a connecting cavity, and the air inlet of the wind shield and the outlet of the bottom plate are connected through the connecting cavity; The bottom plate includes an upper plate, a lower plate and a plurality of connecting plates, the upper plate and the lower plate are opposite to each other, the connecting plate connects the upper plate and the lower plate, and a plurality of the first air ducts and a plurality of the second air ducts are formed between the upper plate, the lower plate and the plurality of connecting plates; The first inlet and the second inlet are respectively located at two ends of the bottom plate in a first direction; the exhaust port is located on a side of the battery box in a second direction, and the second direction is perpendicular to the first direction.

2. The lower box body according to claim 1, characterized in that: The bottom plate further includes a partition for separating the first air duct and the second air duct.

3. The lower box body according to claim 2, characterized in that: A first guide surface and a second guide surface are respectively disposed on both sides of the partition, and the first guide surface and the second guide surface are respectively used to guide the airflow in the first air duct and the second air duct to the outlet.

4. The lower box according to any one of claims 1 to 3, characterized in that: The number of the module installation areas on both sides of the outlet is equal.

5. The lower box according to any one of claims 1 to 3, characterized in that: The top of the air outlet duct includes an inclined curved surface or a flat surface.

6. The lower box body according to claim 1, characterized in that: The upper plate, the lower plate and the plurality of connecting plates are formed by extrusion of aluminum alloy.

7. A battery box, characterized in that: It comprises the lower box body as claimed in any one of claims 1 to 6.

8. The battery box according to claim 7, characterized in that: The battery box also includes a cover plate and a panel assembly, wherein the cover plate is opposite to the bottom plate, and the panel assembly is installed on one side surface of the battery box, and the remaining side surfaces of the battery box are open structures.

9. The battery box according to claim 8, characterized in that: One of the exhaust ports is located on a side of the battery box where the panel assembly is installed, and the panel assembly includes a heat dissipation through hole, which is connected to the exhaust port.

10. The battery box according to claim 7, characterized in that: The battery box is used to be installed in a battery cabinet. The battery cabinet includes a guide structure. The lower box body also includes a mounting beam. The mounting beam is arranged on the bottom plate. The mounting beam is used to be movably connected to the guide structure, thereby providing a guide for the installation of the battery box and for improving the strength of the battery box.

11. Battery cabinet, characterized in that: Comprising a battery box as claimed in any one of claims 7 to 10.

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