Immersed liquid-cooled battery pack and energy storage cabinet

Abstract

The utility model discloses an immersed liquid-cooled battery pack, which comprises a box body, a cold plate and a battery module, the cold plate is arranged at the bottom of the box body and blocks the box body to form a closed cavity, the battery module is arranged in the closed cavity, the battery pack also comprises at least one transmission device, the transmission device is arranged in the closed cavity and is communicated with the closed cavity, and the transmission device is connected with the box body. The conveying device comprises a power device, a liquid inlet pipe with a first inlet and a liquid outlet pipe with a first outlet, the liquid inlet pipe is communicated with a liquid inlet of the power device, the liquid outlet pipe is communicated with a liquid outlet of the power device, the first inlet is located in the top of the box body, and the first outlet is located in the bottom of the box body. The distance between the first inlet and the cold plate is larger than the distance between the first outlet and the cold plate, and the power device is used for enabling liquid flowing in from the liquid inlet of the power device to flow out from the liquid outlet of the power device. The utility model also discloses an energy storage cabinet.

Description

Technical Field

[0001] The utility model relates to the technical field of cooling of electronic equipment, in particular to an immersion-type liquid-cooled battery pack and an energy storage cabinet. Background Art

[0002] A battery pack typically consists of several battery modules, connectors, a battery management system, a cooling system, electrical interfaces, and a housing. The cooling system of a battery pack is used to control battery temperature.

[0003] Batteries generate a large amount of heat during operation. Existing battery packs mainly use immersion liquid cooling technology to dissipate heat. However, existing battery packs have problems such as uneven temperature at different locations inside the battery and between batteries, and low heat dissipation efficiency of the cold plate.

[0004] Therefore, how to design and optimize the heat dissipation structure of the battery pack to improve the heat dissipation efficiency of the cold plate is an urgent problem to be solved in this field. Utility Model Content

[0005] The present invention aims to solve one of the technical problems in the related art to a certain extent. To this end, the present invention provides an immersion liquid-cooled battery pack and an energy storage cabinet.

[0006] As a first aspect of the present utility model, an immersion liquid-cooled battery pack is disclosed, which includes: a box body, a cold plate and a battery module, the cold plate is arranged at the bottom of the box body and seals the box body to form a closed cavity, the battery module is arranged in the closed cavity, the battery pack also includes at least one transmission device, the transmission device is arranged in the closed cavity and communicates with the closed cavity, the transmission device includes a power device, a liquid inlet pipe having a first inlet, and a liquid outlet pipe having a first outlet, the liquid inlet pipe is communicated with the liquid inlet of the power device, and the liquid outlet pipe is communicated with the liquid outlet of the power device, the first inlet is located at the top of the box body, the first outlet is located at the bottom of the box body, the distance between the first inlet and the cold plate is greater than the distance between the first outlet and the cold plate, and the power device is used to make the liquid flowing into the liquid inlet of the power device flow out from the liquid outlet of the power device.

[0007] Furthermore, the position of the first inlet is higher than the top position of the battery module, the position of the first inlet is lower than a set liquid level, and the set liquid level is higher than the height of the top position of the battery module.

[0008] Furthermore, the position of the first inlet is 20 mm to 50 mm lower than the set liquid level.

[0009] Furthermore, the first inlet faces the top of the box.

[0010] Furthermore, the battery pack also includes at least one liquid separation tube, which is arranged at the bottom of the box body, and the first outlet is connected to the liquid separation tube. A plurality of liquid separation ports are formed on the liquid separation tube for diverting and discharging the coolant discharged from the first outlet.

[0011] Furthermore, the liquid separation ports are distributed at intervals along the length direction of the liquid separation tube.

[0012] Furthermore, the battery module includes multiple rows of battery subgroups, the battery pack includes multiple transmission devices, there is a gap between any two adjacent battery subgroups, and the multiple transmission devices correspond to the multiple gaps.

[0013] Furthermore, the interval of at least one side of the battery subgroup corresponds to the transmission device, and the number of the transmission devices satisfies the following formula:

[0014] When M is an odd number, N = (M + 1) / 2;

[0015] When M is an even number, N = M / 2;

[0016] Wherein, N is the number of the transmission devices;

[0017] M is the number of rows of the battery subgroups.

[0018] Furthermore, a cooling pipe is formed inside the cold plate, and an external liquid inlet pipe and an external liquid outlet pipe communicating with the cooling pipe are provided on the outside of the cold plate.

[0019] As a second aspect of the present invention, an energy storage cabinet is disclosed, comprising a cabinet body and at least one battery pack, wherein the battery pack is arranged in the cabinet body, and the battery pack is the battery pack described above.

[0020] The immersion-type liquid-cooled battery pack provided by this invention utilizes a cold plate to cool the internal coolant, which in turn cools the battery modules. The cold plate forms the bottom plate of the battery pack and is connected to the battery housing to form a sealed battery pack structure. Although the coolant in this battery pack structure does not directly exchange heat with the outside world, the presence of the cold plate can promptly remove the heat of the coolant to the outside world, thereby lowering the temperature of the internal coolant and achieving the effect of heat exchange, heat dissipation and cooling. Furthermore, due to the sealing effect of the sealed cavity battery pack, there is no need to introduce complex external piping to connect the coolant for cooling, which reduces costs and isolates the coolant and batteries from external contamination.

[0021] More importantly, the sealed chamber of the battery pack also includes at least one transmission device. The transmission device allows the coolant in the sealed chamber to enter the liquid inlet pipe of the first inlet and flow out of the first outlet of the liquid outlet pipe. This forms a circulation channel for the coolant in the transmission device, allowing the coolant to circulate in the sealed chamber, facilitating rapid heat transfer and thus uniform temperature. The first inlet is at the top of the battery pack case, and the first outlet is at the bottom of the case. The distance between the first inlet and the cold plate is greater than the distance between the first outlet and the cold plate. During operation of the battery pack, hot coolant tends to concentrate at the top of the battery pack, while the coolant at the bottom is continuously cooled by the cold plate to a lower temperature than that at the top. In this way, the first inlet draws the coolant at the higher temperature at the top into the transmission device, where it flows through the circulation channel inside the transmission device and then flows out of the first inlet. The temperature difference between this higher temperature coolant and the cold plate near the first outlet is greater, forming a larger temperature gradient. This greatly increases the heat transfer rate of the cold plate to the coolant flowing out of the first outlet, allowing more heat to be quickly removed by the cold plate, improving the cooling rate and thus greatly improving heat exchange efficiency.

[0022] In addition, the higher temperature coolant flowing out of the first outlet can form forced heat convection with the lower temperature coolant near the first outlet, and the rate of convective heat transfer is proportional to the temperature difference. Heat is quickly carried away by convection, and the temperature is quickly diffused and evenly distributed. Together with the heat conduction method of the cold plate, the coolant at the first outlet is exchanged and cooled, achieving higher heat exchange efficiency, so that the overall coolant temperature is always maintained at a lower level, achieving excellent cooling and heat dissipation effects.

[0023] The power device accelerates and promotes the flow of the coolant in the transmission device, increases the flow speed, and increases the internal circulation frequency, thereby indirectly improving the heat exchange efficiency.

[0024] In the battery pack provided by the present invention, the above-mentioned transmission device structure is used to perform liquid heat dissipation cooling on the battery module, and the high-temperature coolant gathered on the top is directly extracted to the bottom cold plate. The temperature gradient is large, forming a larger heat transfer driving force to take away the heat, the heat transfer rate is faster, and the heat exchange efficiency between the cold plate and the coolant is higher, so that the coolant is effectively and significantly cooled, further improving the cooling and heat dissipation efficiency of the battery. At the same time, the transmission device forms an internal self-circulating coolant circulation path to avoid excessive temperature difference of the coolant at different positions. The transmission device accelerates the circulation flow to achieve coolant with uniform temperature at multiple positions, and the heat dissipation effect at different positions of the battery is consistent, which significantly improves the battery life.

[0025] These features and advantages of the present invention will be detailed in the following detailed description and accompanying drawings. The preferred embodiments or means of the present invention will be fully illustrated in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of the present invention. Furthermore, although multiple features, elements, and components may be present and are labeled with different symbols or numbers for convenience, they all represent components with the same or similar structure or function. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below with reference to the accompanying drawings:

[0027] Figure 1 A schematic diagram of an embodiment of an immersion liquid-cooled battery pack provided by the present invention;

[0028] Figure 2 This is a front schematic diagram of another embodiment of the immersion liquid-cooled battery pack provided by the present invention;

[0029] Figure 3 A schematic top view of an embodiment of an immersion liquid-cooled battery pack provided by the present invention;

[0030] Figure 4 This is a side schematic diagram of an embodiment of the immersion liquid-cooled battery pack provided by the present invention.

[0031] Description of Reference Numerals

[0032] 1: Battery pack 2: Box

[0033] 3: Cold plate 5: Battery module

[0034] 6: Transmission device 7: Dispensing tube

[0035] 8: Coolant 23: Sealed cavity

[0036] 3a: External liquid inlet pipe 3a': External liquid outlet pipe

[0037] 3b: Cooling pipe 5a: Battery sub-pack

[0038] 6a: First inlet 6b: First outlet

[0039] 7a: Liquid separation port 2a: Cooling liquid inlet and outlet DETAILED DESCRIPTION

[0040] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described in the embodiments are intended to explain the present invention and are not to be construed as limiting the present invention.

[0041] References in this specification to "one embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment itself can be included in at least one embodiment disclosed herein. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.

[0042] The applicant's research found that in the prior art, battery packs mostly use cold plates to cool the internal coolant. Cooling water is continuously circulated through the cold plate, and the cooling water cools the cold plate to a lower temperature. The coolant is in direct contact with the heat-generating battery, making its temperature higher than that of the cold plate. The cold plate exchanges heat with the coolant nearby, taking away the heat from the coolant and lowering the temperature of the coolant.

[0043] However, the coolant inside most battery packs is a dynamic coolant, which means it needs to be connected to the outside world and directly exchange heat with the outside world. However, this dynamic coolant requires a correspondingly designed pipeline connection and is not easy to transport. It also requires a more powerful circulation device, which greatly increases the cost.

[0044] However, if the battery pack uses static coolant, that is, a static heat conduction medium is maintained in the battery pack, relying solely on the natural flow of the liquid, this will cause the temperature distribution inside the coolant to be uneven. The coolant near the cold plate has more heat exchange and lower temperature, while the coolant far from the cold plate cannot effectively exchange heat and has a higher temperature. Excessive coolant temperature differences will change the battery's working environment, resulting in a shortened battery life and premature failure.

[0045] To further improve the coolant's heat dissipation efficiency, the mainstream solution is to design the structural position and number of cold plates. For example, cold plates can be placed on all four sides of the battery pack to cool and exchange heat with the coolant. Another example is to arrange multiple cold plates at intervals within the battery pack cavity, with separate cold plates dissipating heat from the coolant and batteries in each corresponding area. However, these structures are complex and require more cold plates, which take up space in the battery pack. The same size battery pack can accommodate fewer batteries and increases costs.

[0046] Based on the above-mentioned issues, the inventors of this application have researched and designed an internal heat circulation system to address the heat exchange issues of the battery pack coolant. Specifically, a transmission device is installed within the battery pack to circulate the coolant, promoting coolant flow, uniformizing the temperature, and improving heat exchange efficiency. The system also allows a cold plate to remove heat from the internally circulating coolant, reducing the overall coolant temperature. However, this internal circulation system still suffers from low coolant heat exchange efficiency. While internal coolant flow can promote temperature diffusion and uniformity, the coolant flow path significantly affects heat exchange efficiency.

[0047] Furthermore, the inventors of the present application optimized the battery pack structure and provided a battery pack with a special transmission device, which changes the cooling path of the coolant flow, thereby greatly improving the heat exchange efficiency of the coolant.

[0048] As the first aspect of the present invention, an immersion liquid-cooled battery pack is shown in FIG. Figure 1 As shown, the battery pack 1 includes: a box body 2, a cold plate 3 and a battery module 5. The cold plate 3 is arranged at the bottom of the box body 2 and blocks the box body 2 to form a closed cavity 23. The battery module 5 is arranged in the closed cavity 23. The battery pack 1 also includes at least one transmission device 6. The transmission device 6 is arranged in the closed cavity 23 and communicates with the closed cavity 23. The transmission device 6 includes a power device, a liquid inlet pipe having a first inlet 6a, and a liquid outlet pipe having a first outlet 6b. The liquid inlet pipe is communicated with the liquid inlet of the power device, and the liquid outlet pipe is communicated with the liquid outlet of the power device. The first inlet 6a is located at the top of the box body 2, and the first outlet 6b is located at the bottom of the box body 2. The distance between the first inlet 6a and the cold plate 3 is greater than the distance between the first outlet 6b and the cold plate 3. The power device is used to make the liquid flowing into the liquid inlet of the power device flow out from the liquid outlet of the power device.

[0049] The battery pack 1 provided by the present invention first uses a cold plate 3 to cool the internal coolant 8, and the coolant 8 then directly contacts and cools the battery module 5. The cold plate 3 constitutes the bottom plate of the battery pack and is connected to the box body 2 to form a closed cavity 23. Although the coolant 8 does not directly exchange heat with the outside world in such a battery pack structure, the presence of the cold plate 3 can promptly remove the heat of the coolant 8, allowing the coolant to indirectly exchange heat with the outside world through the cold plate, thereby reducing the temperature of the internal coolant and achieving the effect of heat dissipation and cooling. At the same time, due to the sealing effect, the battery pack with a closed cavity 23 does not need to introduce additional complex pipes from the outside world to connect the coolant for cooling, and isolates the coolant and battery from external pollution. At the same time, it does not require a more powerful circulation device, which greatly reduces costs.

[0050] The transmission device 6 allows the coolant 8 in the closed chamber 23 to enter from the liquid inlet pipe of the first inlet 6a and flow out from the first outlet 6b of the liquid outlet pipe, thereby forming a circulation channel for the coolant 8 in the transmission device 6, allowing the coolant 8 to circulate in the closed chamber 23, facilitating rapid heat transfer and thus uniforming the temperature.

[0051] Among them, the first inlet 6a is at the top of the battery pack box 2, and the first outlet 6b is at the bottom of the box 2, and the distance between the first inlet 6a and the cold plate 3 is greater than the distance between the first outlet 6b and the cold plate 3. The reason for this arrangement is that during the operation of the battery pack, the hot coolant tends to gather at the top of the battery pack, while the coolant at the bottom is continuously cooled by the cold plate to make its temperature lower than that of the top. In this way, the first inlet 6a draws the coolant with a higher temperature at the top into the transmission device 6, flows through the circulation channel inside the transmission device 6, and then flows out from the first outlet 6b. Figure 1 The middle dotted line shows the flow direction of the coolant in the transmission device. The temperature difference between this part of the coolant with higher temperature and the cold plate 3 near the first outlet 6b is greater, forming a larger temperature gradient, thereby greatly increasing the heat transfer speed, making the cold plate 3 increase the heat exchange amount of the coolant flowing out of the first outlet 6b and shortening the heat exchange time. More heat is quickly taken away by the cold plate, the cooling rate is increased, and the heat exchange efficiency is greatly increased, so that the battery module 5 can be effectively cooled to prevent overheating and maintain the battery module within a suitable operating temperature range.

[0052] In addition, when the higher temperature coolant flowing out of the first outlet 6b can form forced heat convection with the nearby lower temperature coolant, and the rate of convective heat transfer is proportional to the temperature difference, the heat can also be quickly taken away by the other part of the coolant through convection, and the temperature is quickly diffused and uniform. Together with the heat conduction method of the cold plate 3, the coolant at the first outlet 6b is exchanged and cooled, achieving higher heat exchange efficiency, so that the overall coolant temperature is always maintained at a lower level, achieving excellent cooling and heat dissipation effects.

[0053] The power device accelerates and promotes the flow of the coolant in the transmission device, increases the flow rate, and increases the frequency of the internal circulation, thereby indirectly improving the heat exchange efficiency. The present invention does not specifically limit the specific structure of the power device. It only needs to provide a driving force to extract, adsorb and discharge the coolant and be able to transport the liquid. For example, the power device uses a mechanical pump, and can further be a centrifugal pump. Its structural feature is that it is internally provided with a high-speed rotating impeller, which can enable the liquid to obtain centrifugal force and flow out; it can also be a spiral pump. When the motor drives the spiral shaft to rotate, the spiral blades will drive the liquid in the chamber to rise in an axial spiral to achieve liquid transportation; piston pumps, gear pumps, peristaltic pumps, etc. and a combination of multiple pumps can also be used. In order to reduce the volume of the battery pack occupied by the transmission device and increase the battery storage space, the power device is preferably a booster pump with rotating blades inside.

[0054] The present invention does not impose any special restrictions on the parameters of the pump. A mechanical pump is selected as the power device. When discharging the coolant, the coolant has a certain head, flow rate, and flow rate. The discharged coolant can be discharged a longer distance, thereby increasing its heat transfer area, cooling faster, and improving heat exchange efficiency. In some embodiments, the rotation speed of the blades is increased, so that the flow rate of the absorbed coolant is larger, and the discharge flow rate is also increased accordingly. A larger amount of coolant exchanges heat with the cold plate, and the heat exchange efficiency is higher. In some embodiments, the power of the pump is increased, thereby increasing the head of the coolant discharged from the first outlet. Although the flow rate will be adaptively reduced, the coolant is discharged farther, the heat transfer area is larger, the cooling rate is faster, and the heat exchange efficiency is also improved. It can be understood that the parameters of the pump are adjusted to allow the coolant to be discharged from the first outlet with a larger flow rate, faster flow rate, and greater head, so as to fully exchange heat with the cold plate and significantly improve the heat exchange efficiency.

[0055] The present invention does not impose any specific restrictions on the size of the coolant discharged from the first outlet 6b. The larger the size of the first outlet 6b, the greater the amount of liquid that can be discharged, and the cold plate 3 can exchange heat with a larger amount of coolant. However, if the outlet size is too large and exceeds the rated flow rate of the water pump, it may cause low pump efficiency and waste energy. In addition, as the outlet size decreases, the flow rate will increase, and the kinetic energy of the water will increase, which will help the liquid overcome the effects of external forces during the lift. Under the condition of a certain flow rate, a higher lift value can be achieved, the coolant can be discharged farther, and the heat exchange efficiency will also be improved.

[0056] To draw more hot coolant from the top into the transmission device, the first inlet 6a should be as large as possible. A larger inlet allows for a greater flow of coolant, allowing for a shorter period of time to draw in more hot coolant for cooling the cold plate 3. However, the first inlet 6a should not be too large, as the design should also consider the need to leave more room within the battery pack to accommodate the battery modules. Preferably, the first outlet 6b is smaller than or equal to the first inlet 6a, allowing the first inlet 6a to draw more coolant into the transmission device. The transmission device then allows the coolant to be discharged from the first outlet 6b at a greater flow rate, velocity, and lift, achieving sufficient heat exchange with the cold plate and improving heat exchange efficiency.

[0057] To ensure that the transfer device 6 can evenly and comprehensively absorb the hot coolant from the top of the battery module 5, the battery pack is operated so that the coolant 8 fills the sealed cavity and completely submerges the battery module 5. The first inlet 6a is positioned above the top of the battery module 5 and below a set liquid level. The set liquid level is higher than the height of the top of the battery module 5, which is the height of the coolant during operation. The first inlet 6a should not be positioned below the battery module 5. A first inlet 6a that is too low will absorb coolant not from the top portion of the coolant that is most heated, resulting in reduced heat exchange efficiency. However, the first inlet 6a should not be positioned too high. A too high position will bring it closer to the coolant level, making it more likely that the first inlet 6a will absorb gas above the liquid level, which will also reduce heat exchange efficiency. Preferably, the first inlet 6a is positioned 20 mm to 50 mm below the set liquid level and above the top of the battery module 5.

[0058] In order to further enable the transmission device 6 to evenly and comprehensively absorb the hot coolant from the top of the battery module 5 , the first inlet 6 a is arranged to face the top of the box body 2 .

[0059] In some other battery structure implementations, the coolant near the cold plate is also transported to the top for cooling. The temperature of the coolant near the cold plate is very low, and the positive and negative poles of the battery are often arranged on the top of the battery pack, which is more prone to heat. In addition, the liquid with high temperature tends to flow upward, while the liquid with low temperature tends to sink. Therefore, the temperature of the top of the battery pack is often higher than that of the bottom, and the temperature of the coolant around it is also high due to heat exchange. Although this approach can cool the coolant at the bottom to the top, it reduces the heat exchange efficiency of the cold plate to the coolant.

[0060] The battery pack also includes at least one liquid separation tube 7, which is arranged at the bottom of the box body 2. The first outlet 6b is connected to the liquid separation tube 7. A plurality of liquid separation ports 7a are formed on the liquid separation tube 7 for diverting and discharging the coolant discharged from the first outlet 6b. In order to evenly distribute the coolant from the first outlet 6b and discharge it to the bottom of the box body, it is preferred that the liquid separation ports 7a are spaced apart along the length direction of the liquid separation tube 7, so that the cold plate at the bottom can fully cool the coolant discharged from the plurality of liquid separation ports, thereby achieving a better temperature uniformity distribution effect.

[0061] As an optional implementation method, Figure 3 As shown, the battery module 5 includes multiple rows of battery subgroups 5a, and the battery pack 1 includes multiple transmission devices 6. There is a gap between any two adjacent battery subgroups 5a, and the multiple transmission devices 6 correspond to the multiple gaps.

[0062] Preferably, the spacing on at least one side of the battery subgroup corresponds to the transmission device, so that the hot coolant generated by the heat exchange of each battery subgroup can be absorbed and collected by the transmission device on one side and discharged to the bottom for cooling. This arrangement of the transmission device and the battery subgroup can achieve better uniform temperature distribution. The number of transmission devices satisfies the following formula:

[0063] When M is an odd number, N = (M + 1) / 2;

[0064] When M is an even number, N = M / 2;

[0065] Wherein, N is the number of transmission devices;

[0066] M is the number of rows of battery subgroups.

[0067] like Figure 2 、 Figure 3 and Figure 4 As shown, a cooling pipe 3b is formed inside the cold plate 3, and an external liquid inlet pipe 3a and an external liquid outlet pipe 3a' are provided on the outside of the cold plate 3, communicating with the cooling pipe 3b. In this application, only the cold plate 3 functions as a direct external heat exchanger. The internal detection device of the battery pack monitors the temperature of the coolant or battery in the battery pack, and then regulates the flow rate and flow rate of the external liquid inlet pipe 3a and the external liquid outlet pipe 3a', thereby achieving further temperature control and cooling of the cold plate, thereby indirectly cooling the battery pack coolant and batteries.

[0068] like Figure 2 and Figure 3 As shown, the battery pack of the present invention also includes a coolant inlet and outlet 2a. Specifically, the coolant inlet and outlet 2a is an adjustable valve device, but this device is always in a closed state during the operation of the battery pack. The coolant inlet and outlet 2a is only opened during the initial introduction of the coolant and is used for discharge when the coolant is replaced regularly.

[0069] As a second aspect of the present invention, an energy storage cabinet is disclosed, comprising a cabinet body and at least one battery pack, wherein the battery pack is arranged in the cabinet body, and the battery pack is the above-mentioned battery pack. In the energy storage cabinet provided by the present invention, the battery pack therein utilizes the above-mentioned transmission device structure to perform liquid heat dissipation cooling on the battery module, and directly extracts the high-temperature coolant gathered at the top to the bottom cold plate. The temperature gradient is large, forming a greater heat transfer driving force to take away the heat, the heat transfer rate is faster, and the heat exchange efficiency between the cold plate and the coolant is higher, so that the coolant is effectively and significantly cooled, further improving the cooling and heat dissipation efficiency of the battery. At the same time, the transmission device forms an internal self-circulating coolant circulation path to avoid excessive temperature differences of the coolant at different positions. The transmission device accelerates the circulation flow, achieving coolant with uniform temperature at multiple positions, and having consistent heat dissipation effect at different positions of the battery, significantly improving the battery life.

[0070] The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modifications that do not deviate from the functional and structural principles of the present invention are included within the scope of the claims.

Claims

1. An immersion liquid-cooled battery pack, the battery pack (1) comprising: A box (2), a cold plate (3) and a battery module (5), wherein the cold plate is arranged at the bottom of the box and blocks the box to form a closed cavity (23), and the battery module is arranged in the closed cavity, characterized in that the battery pack also includes at least one transmission device (6), the transmission device is arranged in the closed cavity and communicates with the closed cavity, the transmission device (6) includes a power device, a liquid inlet pipe with a first inlet (6a), and a liquid outlet pipe with a first outlet (6b), the liquid inlet pipe is communicated with the liquid inlet of the power device, and the liquid outlet pipe is communicated with the liquid outlet of the power device, the first inlet (6a) is located at the top of the box, and the first outlet (6b) is located at the bottom of the box, the distance between the first inlet (6a) and the cold plate is greater than the distance between the first outlet and the cold plate, and the power device is used to make the liquid flowing into the liquid inlet of the power device flow out from the liquid outlet of the power device.

2. The battery pack according to claim 1, wherein: The position of the first inlet is higher than the top position of the battery module, the position of the first inlet is lower than a set liquid level, and the set liquid level is higher than the height of the top position of the battery module.

3. The battery pack according to claim 2, wherein: The position of the first inlet is 20 mm to 50 mm lower than the set liquid level.

4. The battery pack according to claim 2, wherein: The first inlet is toward the top of the box.

5. The battery pack according to claim 1, wherein: The battery pack further comprises at least one liquid separation pipe, which is arranged at the bottom of the box body. The first outlet is communicated with the liquid separation pipe (7), and a plurality of liquid separation ports (7a) are formed on the liquid separation pipe for separating and discharging the coolant discharged from the first outlet.

6. The battery pack according to claim 5, characterized in that: The liquid separation ports are distributed at intervals along the length direction of the liquid separation tube.

7. The battery pack according to any one of claims 1 to 6, characterized in that: The battery module includes multiple rows of battery subgroups, and the battery pack includes multiple transmission devices. There is a gap between any two adjacent battery subgroups, and the multiple transmission devices correspond to the multiple gaps.

8. The battery pack according to claim 7, characterized in that: The interval on at least one side of the battery subgroup corresponds to the transmission device, and the number of the transmission devices satisfies the following formula: When M is an odd number, N = (M + 1) / 2; When M is an even number, N = M / 2; Wherein, N is the number of the transmission devices; M is the number of rows of the battery subgroups.

9. The battery pack according to any one of claims 1 to 6, characterized in that: A cooling pipe is formed inside the cold plate, and an external liquid inlet pipe and an external liquid outlet pipe communicating with the cooling pipe are provided on the outside of the cold plate.

10. An energy storage cabinet, comprising a cabinet body and at least one battery pack, wherein the battery pack is arranged in the cabinet body, characterized in that: The battery pack is the battery pack according to any one of claims 1 to 9.

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