An immersion liquid cooling energy storage system

Abstract

Embodiments of the present invention relate to the technical field of electrical energy storage, and disclose an immersion liquid-cooled energy storage system. In the present invention, a liquid storage tank with multiple liquid leakage holes is arranged above the battery cluster unit. The liquid outlet pipe outside the energy storage box transports the coolant to the liquid storage tank through a cooling pipe. The coolant in the liquid storage tank flows downward from the liquid leakage holes under the action of gravity and cools the battery cluster unit. In this way, the coolant can accurately cool the battery cluster unit, reduce the dead zone inside the energy storage box, cool the area with concentrated heat generation, and enhance the temperature equalization effect. Moreover, since the coolant flows and adheres to the surface of the battery cluster unit under the action of gravity, it is not necessary for the coolant to fill the energy storage box like in the traditional immersion liquid cooling, which can reduce the amount of coolant used.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of electrical energy storage, and particularly to an immersion liquid-cooled energy storage system. Background Art

[0002] New energy technologies such as wind energy and solar energy have developed rapidly, and the development of the supporting battery energy storage system has also advanced by leaps and bounds. Currently, to improve efficiency, the battery energy storage system shows a technical trend of high energy density development, which easily increases the heat generation of the battery energy storage system and leads to an increased risk of thermal runaway. Therefore, there is a need to provide a battery energy storage system with high cooling performance.

[0003] The immersion liquid-cooled technology is a cooling technology that directly immerses energy storage units such as battery packs or battery cells in an insulating coolant, and uses the coolant to absorb the heat generated by the energy storage units during operation to ensure that the battery operates within the optimal temperature range. Compared with the traditional air-cooled technology, the immersion liquid-cooled has higher cooling efficiency and safety performance.

[0004] The existing immersion liquid-cooled energy storage systems usually use an insulating coolant to fill the energy storage cabinet so that the battery units in the energy storage cabinet are in an immersed state. However, in the existing immersion liquid-cooled method, due to the existence of dead zones in the energy storage cabinet and the problem of insufficient heat exchange caused by different flow rates in different regions, the temperature equalization effect is poor. Summary of the Invention

[0005] The purpose of the embodiments of the present invention is to provide an immersion liquid-cooled energy storage system, which can reduce the dead zone inside the energy storage box, cool the area with concentrated heat generation, reduce the amount of coolant used, and enhance the temperature equalization effect.

[0006] To solve the above technical problems, the embodiments of the present invention provide an immersion liquid-cooled energy storage system, including:

[0007] An energy storage box; a battery cluster unit disposed in the energy storage box; an infusion pipe disposed outside the energy storage box, the infusion pipe being used to convey a coolant; a liquid storage tank disposed in the energy storage box, the liquid storage tank including a bottom plate and a plurality of side plates connecting the bottom plate, the bottom plate being fixed on the top of the battery cluster unit and provided with a plurality of liquid leakage holes; the plurality of side plates are sequentially connected end to end along the edge of the bottom plate and extend in a direction away from the battery cluster unit; a cooling pipe disposed on the side of the liquid storage tank facing away from the battery cluster unit, one end of the cooling pipe is connected to the infusion pipe, and the other end is disposed opposite to the liquid storage tank, the cooling pipe is used to convey the coolant to the liquid storage tank, and the coolant flows downward through the liquid leakage holes under the action of gravity and cools the battery cluster unit.

[0008] In the immersion liquid cooling energy storage system according to the embodiment of the present invention, a liquid storage tank with multiple liquid leakage holes is arranged above the battery cluster unit. The liquid outlet pipe outside the energy storage box transports the coolant to the liquid storage tank through the cooling pipe. The coolant in the liquid storage tank flows downward from the liquid leakage holes under the action of gravity and cools the battery cluster unit. In this way, the coolant can accurately cool the battery cluster unit, reduce the dead zone inside the energy storage box, cool the area with concentrated heat generation, and enhance the temperature equalization effect. Moreover, since the coolant flows and adheres to the surface of the battery cluster unit under the action of gravity, unlike the traditional immersion liquid cooling where the energy storage box is filled with coolant, the amount of coolant used can be reduced.

[0009] Optionally, it further includes a plurality of support members arranged at intervals in the vertical direction. The plurality of support members are fixed inside the energy storage box. The battery cluster units are multiple, and the multiple battery cluster units are respectively arranged on the support members in a one-to-one correspondence; the cooling pipes are multiple and are arranged at intervals in the vertical direction. One ends of the multiple cooling pipes are connected to the liquid infusion pipe, and the other ends of the multiple cooling pipes are respectively arranged opposite to the liquid storage tank.

[0010] Optionally, the battery cluster unit includes a plurality of battery cells, and there is a heat dissipation gap between adjacent two battery cells. The coolant in the liquid storage tank enters the heat dissipation gap through the liquid leakage holes to cool the battery cells.

[0011] Optionally, each cooling pipe has a plurality of branch pipes arranged at intervals in the horizontal direction. Each branch pipe has a liquid outlet, and the plurality of branch pipes transport the coolant to the corresponding liquid storage tank through the corresponding liquid outlets.

[0012] Optionally, the liquid outlet is set such that the inner dimension in the horizontal direction is greater than the inner dimension in the vertical direction.

[0013] Optionally, the multiple liquid leakage holes are arranged in an array, and some of the liquid leakage holes are arranged along the extending direction of the heat dissipation gap and are directly opposite to the heat dissipation gap.

[0014] Optionally, the liquid leakage holes directly opposite to the heat dissipation gap are arranged directly opposite to the liquid outlets.

[0015] Optionally, a drainage portion is arranged on the side of the edge of the liquid leakage hole directly opposite to the heat dissipation gap away from the side plate. One end of the drainage portion is connected to the edge of the liquid leakage hole, and the other end is connected to the side wall of the battery cell. The drainage portion is used to drain the coolant flowing out of the liquid leakage hole to the side wall of the battery cell.

[0016] Optionally, the edge of the liquid leakage hole directly opposite to the heat dissipation gap in the arrangement direction of the battery cells does not exceed the edge of the side wall of the battery cell.

[0017] Optionally, at least one of the side plates is provided with at least one overflow port. Description of the Drawings

[0018] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplary illustrations do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements, unless otherwise stated. The drawings in the figures do not constitute a scale limitation.

[0019] Figure 1 is a schematic structural diagram of the immersion liquid-cooled energy storage system according to the first embodiment of the present invention;

[0020] Figure 2 is a schematic structural diagram of the layer cell cluster of the immersion liquid-cooled energy storage system according to the first embodiment of the present invention;

[0021] Figure 3 is a schematic structural diagram of the liquid storage tank of the immersion liquid-cooled energy storage system according to the first embodiment of the present invention;

[0022] Figure 4 is Figure 2 a top view schematic diagram of the layer cell cluster of

[0023] Figure 5 is a schematic structural diagram of the cooling pipe and the branch pipe of the immersion liquid-cooled energy storage system according to the first embodiment of the present invention;

[0024] Figure 6 is Figure 5 a bottom view schematic diagram of the cooling pipe and the branch pipe of

[0025] Figure 7 is Figure 4 a cross-sectional schematic diagram of the layer cell cluster along the line AA' of

[0026] Figure 8 is a schematic structural diagram of a housing of the immersion liquid-cooled energy storage system according to the second embodiment of the present invention;

[0027] Figure 9 is Figure 8 a top view schematic diagram of the housing of

[0028] Figure 10 is an exploded schematic diagram of the structure of the housing and the layer cell cluster of the immersion liquid-cooled energy storage system according to the second embodiment of the present invention;

[0029] Figure 11 is a schematic structural diagram of another housing of the immersion liquid-cooled energy storage system according to the second embodiment of the present invention;

[0030] Figure 12 is Figure 11 a top view schematic diagram of the housing in Detailed Implementation Modes

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will elaborate on each implementation mode of the present invention with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that in each implementation mode of the present invention, many technical details are provided to help readers better understand the present invention. However, even without these technical details and various changes and modifications based on the following implementation modes, the technical solutions claimed by the present invention can still be achieved.

[0032] In the implementation modes of the present invention, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are mainly used to better describe the present invention and its implementation modes, rather than to limit that the indicated devices, elements, or components must have a specific orientation or be constructed and operated in a specific orientation.

[0033] Moreover, in addition to being used to represent the orientation or positional relationship, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the present invention can be understood according to the specific circumstances.

[0034] In addition, the terms "install", "set", "provide", "open", "connect", "link" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there can be internal communication between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0035] In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements, or components (the specific types and structures may be the same or different), rather than to indicate or imply the relative importance and quantity of the indicated devices, elements, or components. Unless otherwise specified, the meaning of "a plurality" is two or more.

[0036] In an existing immersion liquid-cooled energy storage system during actual operation, since the density of the liquid decreases after heating and it accumulates in the upper layer of the energy storage tank, the overall temperature stratification phenomenon of the upper layer being hot and the lower layer being cold appears inside the energy storage tank. The flow rates of the coolant at different positions are different, and the heat exchange rate between the battery unit and the coolant is also uneven. All these defects lead to the problems of dead zones in the energy storage tank and insufficient heat exchange caused by different flow rates in different regions, resulting in poor temperature equalization effect.

[0037] For the immersion liquid-cooled energy storage system according to an embodiment of the present invention, a liquid storage tank with multiple liquid leakage holes is arranged above the battery cluster unit. The liquid outlet pipe outside the energy storage tank transports the coolant to the liquid storage tank through a cooling pipe. The coolant in the liquid storage tank flows downward from the liquid leakage holes under the action of gravity and cools the battery cluster unit. In this way, the coolant can accurately cool the battery cluster unit, reduce the dead zones inside the energy storage tank, cool the regions with concentrated heat generation, and enhance the temperature equalization effect. Moreover, since the coolant flows and adheres to the surface of the battery cluster unit under the action of gravity, it is not necessary for the coolant to fill the energy storage tank like in the traditional immersion liquid cooling, which can reduce the consumption of the coolant.

[0038] It should be noted that the "immersion liquid-cooled energy storage system" mentioned in this embodiment can be either an industrial and commercial energy storage system (abbreviated as industrial and commercial storage) or a large-scale energy storage system (abbreviated as large storage). Industrial and commercial storage usually serves industrial and commercial users, with a relatively small scale and a capacity generally between several kilowatts and several megawatts, while large storage serves a wider power grid and energy market, with a larger scale and a capacity usually dozens of megawatts or even larger.

[0039] The implementation details of the immersion liquid-cooled energy storage system according to the first embodiment of the present invention will be specifically described below. The following content is only the implementation details provided for convenient understanding and is not necessary for implementing this solution.

[0040] See Figures 1 to 3 , the immersion energy storage system 100 of this embodiment includes: an energy storage tank 110, a battery cluster unit 120 arranged in the energy storage tank 110, an infusion pipe 130 arranged outside the energy storage tank 110 for transporting the coolant, a liquid storage tank 140 arranged in the energy storage tank 110, and a cooling pipe 150 arranged on the side of the liquid storage tank 140 facing away from the battery cluster unit 120.

[0041] Among them, the liquid storage tank 140 includes a bottom plate 141 and a plurality of side plates 142 connecting the bottom plate 141. The bottom plate 141 is fixed on the top of the battery cluster unit 120 and is provided with a plurality of liquid leakage holes 141a. The plurality of side plates 142 are sequentially connected end to end along the edge of the bottom plate 141 and extend in a direction away from the battery cluster unit 120.

[0042] One end of the cooling pipe 150 is connected to the liquid infusion pipe 130, and the other end is disposed opposite to the liquid storage tank 140. The cooling pipe 150 is used to convey the coolant to the liquid storage tank 140. The coolant flows downward through the liquid leakage hole 141a under the action of gravity and cools the battery cluster unit 120.

[0043] During the operation of the battery cluster unit 120, the liquid infusion pipe 130 conveys the coolant to the cooling pipe 150. The coolant flows into the liquid storage tank 140 through the cooling pipe 150, is dispersed by the liquid leakage hole 141a of the liquid storage tank 140, and then flows downward under the action of gravity to cool the battery cluster unit 120. In this way, the coolant can accurately cool the battery cluster unit 120, reduce the dead zone inside the energy storage box 110, cool the area with concentrated heat generation, enhance the temperature equalization effect, and at the same time reduce the consumption of the coolant.

[0044] It can be understood that the coolant flowing down from the liquid leakage hole 141a can flow down in the form of dripping or in the form of a continuous flowing "water stream". When flowing down in the form of dripping, the dripping speed can be controlled by controlling the flow rate per unit time of the cooling pipe 150. And because of the setting of the embodiment, the coolant can cover the surface of the battery cluster unit 120. For the battery cluster unit 120, it can also be regarded as immersion liquid cooling.

[0045] At least one side plate 142 of the liquid storage tank 140 can be provided with at least one overflow port 142a. The overflow port 142a can prevent the accumulation of the coolant in the liquid storage tank 140. In this embodiment, the overflow port 142a can also be used as the wire harness outlet of the battery cluster unit 120. In this way, the overall structure of the immersion liquid-cooled energy storage system 100 can be simplified.

[0046] The overflow port 142a can be a notch provided at the top edge of the side plate 142, or a through hole provided in the middle or lower part of the side plate 142. In some embodiments, the overflow port 142a can be set such that in the vertical direction, its caliber gradually decreases from top to bottom. For example, it can be set as an inverted triangle, an inverted trapezoid, a semi-circle, a semi-ellipse or other similar shapes. In this way, when the accumulation of the coolant in the liquid storage tank 140 is relatively serious and the liquid level is relatively high, the caliber of the overflow port 142a is relatively large, and the coolant can be discharged quickly to relieve the accumulation of the coolant. When the accumulation of the coolant is relieved and the liquid level decreases, at the position where the caliber of the corresponding overflow port 142a is relatively small, the flow rate of the coolant flowing out from the overflow port 142a can be reduced. While relieving the accumulation of the coolant, it ensures that more coolant can flow downward from the liquid leakage hole 141a to cool the battery cluster unit 120, making the coolant have a high utilization rate.

[0047] The edge of the side plate 142 surrounding the overflow port 142a can be provided with a flow guiding structure. In this way, the situation where the edge of the overflow port 142a hinders the flow of the coolant due to processing errors during the processing of the product can be solved. For example, a chamfer can be provided at the edge of the side plate 142 surrounding the overflow port 142a, so that the thickness of the side plate 142 in this area gradually decreases in the direction from the inner edge of the side plate 142 towards the outer edge of the side plate 142. Optionally, the chamfer can be an inclined chamfer or a rounded chamfer.

[0048] The immersion liquid-cooled energy storage system 100 further includes a liquid outlet pipe (not shown in the figure) provided at the bottom of the energy storage tank 110. One end of the liquid outlet pipe is connected to the energy storage tank 110 and communicates with the internal space of the energy storage tank 110, and the other end is located outside the energy storage tank 110. The liquid outlet pipe is used to discharge the coolant accumulated inside the energy storage tank 110 to realize the circulation of the coolant.

[0049] Outside the energy storage tank 110, the immersion liquid-cooled energy storage system 100 can be provided with a circulation device (not shown in the figure), such as a pump, and a cooling device, such as a condensation device. The pump can provide power to drive the coolant to flow out of the liquid outlet pipe and then enter the inside of the energy storage tank 110 again for cooling. It can be understood that before the coolant enters the energy storage tank 110 again for cooling, the coolant is cooled by the cooling device so that the coolant can efficiently cool the battery cluster unit 120.

[0050] It should be noted that the energy storage tank 110 is an immersion box body of the immersion liquid-cooled energy storage system 100 and is used to accommodate the battery cluster and the coolant. The immersion liquid-cooled energy storage system 100 also has a sealed box body (not shown in the figure) for accommodating the energy storage tank 110 and the above-mentioned circulation device and cooling device. Moreover, the circuit system including control devices such as a power control board and an inverter in the immersion liquid-cooled energy storage system 100 is also arranged in the sealed box body.

[0051] A valve can be provided at the liquid outlet pipe. By controlling the flow rate of the valve and the flow rate of the liquid delivery pipe 130, the circulation speed of the coolant can be controlled. In addition, if there is a situation of battery thermal runaway inside the immersion liquid-cooled energy storage system 100, the valve flow rate can also be reduced or the valve can be closed, and at the same time, the flow rate of the liquid delivery pipe 130 can be increased so that the internal space of the energy storage tank 110 is completely filled with the coolant to achieve full immersion, which can effectively control the thermal runaway.

[0052] Refer to again Figure 1 , the immersion liquid-cooled energy storage system 100 further includes a support member 160 fixed inside the energy storage tank 110. The support member 160 is at least one, and divides the internal space of the energy storage tank 110 into at least two vertically distributed spaces for accommodating the battery cluster unit 120.

[0053] In some embodiments, there are multiple support members 160, and the multiple support members 160 are arranged at intervals in the vertical direction, dividing the internal space of the energy storage box 110 into multiple spaces distributed in the vertical direction for accommodating the battery cluster units 120. Correspondingly, a corresponding liquid storage tank 140 is provided on the top of each battery cluster unit 120. At this time, the cooling pipe 150 is also arranged in multiple numbers and arranged at intervals in the vertical direction. Each cooling pipe 150 has one end connected to the infusion pipe 130, and the other end of each cooling pipe 150 is arranged above the corresponding liquid storage tank 140, for inputting coolant into the corresponding liquid storage tank 140. The support member 160 is used to support the battery cluster unit 120. It can be understood that the support member 160 can be a support plate, a bracket, etc., and the multiple support members 160 can be an integrated structure or an independent structure.

[0054] When the support member 160 is a support plate, it can be set as a liquid cooling plate, the plate is provided with a liquid cooling channel for conveying cooling liquid, the liquid cooling plate is provided with a liquid inlet and a first liquid outlet, the liquid inlet can be connected to the cooling pipe 150, the first liquid outlet can be kept open, or it can be connected to a pipeline, through which the cooling liquid flowing out of the liquid cooling plate is conveyed to the bottom of the energy storage box 110. In this way, the support member 160, as a liquid cooling plate, can cool down the bottom of the battery cluster unit 120, further improving the cooling effect of the battery cluster unit 120 and the overall temperature uniformity effect of the energy storage system.

[0055] When a liquid cooling channel is provided inside the support member 160 , the liquid cooling channel can be provided as a serpentine channel to improve the cooling effect. In addition, to facilitate the connection between the first liquid outlet and the cooling pipe 150 , the first liquid outlet can be provided on a side of the support member 160 close to the cooling pipe 150 .

[0056] When the support member 160 is a bracket, such as a grid-shaped bracket, it is convenient for the coolant flowing out of the liquid storage tank 140 to flow downward, which is beneficial to the circulation of the coolant.

[0057] In some other embodiments, a support member 160 may have multiple battery cluster units 120 arranged in a horizontal direction, and these battery cluster units 120 form a layer battery cluster. Each battery cluster unit 120 has a corresponding liquid storage tank 140, and each liquid storage tank 140 also has a corresponding cooling pipe 150. In this case, the liquid infusion tube 130 can be connected to multiple liquid distribution tubes (not shown) in the vertical direction, and each liquid distribution tube is connected to multiple cooling pipes 150 corresponding to the multiple battery cluster units 120 arranged on a support member 160.

[0058] Or, see Figures 2 to 4, each cooling pipe 150 can be connected with multiple branch pipes 151. The multiple branch pipes 151 are arranged in the horizontal direction, for example, they can be sequentially arranged along the arrangement direction of multiple battery cluster units 120. Each branch pipe 151 has a second liquid outlet 151a. The multiple branch pipes 151 on one cooling pipe 150 are all used to convey the coolant to the corresponding liquid storage tank 140 of this cooling pipe 150. In this way, the coolant can be conveyed to different liquid storage tanks 140 simultaneously, and the coolant can flow downward from multiple liquid leakage holes 141a to cool the battery cells 121, improving the cooling efficiency.

[0059] Participate Figure 5 And Figure 6 , in some embodiments, the second liquid outlet 151a is set such that the inner dimension in the horizontal direction is greater than the inner dimension in the vertical direction. Or, the branch pipe 151 can also be set to have a dimension in the horizontal direction greater than the dimension in the vertical direction. In other words, the branch pipe 151 is set to be flat-shaped, which can reduce the dimension of the branch pipe 151 in the vertical direction, thereby reducing the height of the immersion liquid-cooled energy storage system 100. Further, the cooling pipe 150 can also be set to be flat-shaped.

[0060] Correspondingly, the second liquid outlet 151a can be set to be triangular, rhombic, rectangular, waist-shaped, oval, wavy linear, etc., which can not only reduce the volume occupied by the flow channel in the vertical direction, but also increase the contact area between the coolant flowing out from the second liquid outlet 151a and the bottom plate 141, further accelerating the speed of the coolant covering the bottom plate 141 and improving the cooling efficiency.

[0061] The part of the side plate 142 close to the second liquid outlet 151a can be set to bend or incline towards the inside of the liquid storage tank 140; or, a plate-like structure extending towards the second liquid outlet 151a can be provided at the top of the part of the side plate 142 close to the second liquid outlet 151a; or, the distance between the second liquid outlet 151a and the bottom plate 141 can be reduced to reduce or avoid the impact of the coolant on the bottom plate 141. With such a setting, the situation of the coolant splashing when flowing out from the second liquid outlet 151a can be avoided.

[0062] It can be understood that, according to the actual specification size of the immersion liquid-cooled energy storage system 100, different sizes of the second liquid outlet 151a can be set, which can also reduce or avoid the splashing of the coolant. For example, the diameter of the liquid outlet 151a can be set to 10 mm - 50 mm.

[0063] Due to the large specifications of industrial and commercial energy storage or large-scale energy storage, the existing liquid cooling channel design cannot ensure the consistency of the cooling efficiency in different regions inside the energy storage system. For example, there are some regions inside the energy storage system where the coolant cannot reach or submerge, or the coolant flow rates in different regions inside the energy storage system are different, and the heat transfer efficiency varies significantly. The regions where the coolant cannot submerge and the regions with lower heat transfer efficiency are usually called dead zones. The gap between adjacent batteries in the energy storage system is a typical location for forming dead zones. Therefore, submerging the gap between batteries with coolant and improving the flow efficiency of the coolant in the gap between batteries are important means to reduce dead zones.

[0064] See Figure 7 , the battery cluster unit 120 generally includes a plurality of battery cells 121, and there is a heat dissipation gap 122 between two adjacent battery cells 121. Specifically, the coolant flowing out of the liquid leakage hole 141a of the liquid storage tank 140 enters the heat dissipation gap 122 and contacts the side wall of the battery cell 121 to achieve heat exchange.

[0065] Corresponding to the multiple heat dissipation gaps 122 formed by the plurality of battery cells 121, at least some of the multiple liquid leakage holes 141a arranged in an array are arranged along the extension direction of the heat dissipation gap 122 and are directly opposite to the heat dissipation gap 122. Specifically, if each heat dissipation gap 122 extends along a straight line, there are multiple liquid leakage holes 141a directly opposite to this heat dissipation gap 122 and arranged along the extension direction of this heat dissipation gap 122. Moreover, each heat dissipation gap 122 has a corresponding plurality of liquid leakage holes 141a. By setting like this, the coolant can accurately enter the heat dissipation gap 122 between adjacent battery cells 121. At the same time, the coolant at different positions flows downward under the action of gravity, and the fluidity tends to be consistent, which can reduce the cooling dead zones of the immersion liquid cooling energy storage system 100 and improve the overall temperature uniformity effect.

[0066] See again Figure 4 and Figure 7 , in some embodiments, the liquid leakage holes 141a can also be arranged in a staggered manner. Specifically, considering the series connection requirements of multiple adjacent battery cells 121, the electrodes of adjacent battery cells 121 need to be electrically connected through the staggered metal sheets 124. Since the metal sheets 124 need to occupy part of the space of the bottom plate 141, the liquid leakage holes 141a are arranged at the positions on the bottom plate 141 where there are no metal sheets 124, and the regions where there are metal sheets 124 can be without liquid leakage holes 141a. Therefore, the liquid leakage holes 141a are arranged in a staggered manner as a whole. At this time, a heat dissipation gap 122 may correspond to a larger liquid leakage hole 141a or a plurality of smaller liquid leakage holes 141a.

[0067] In still some embodiments, the middle part of the metal sheet 124 connecting two adjacent battery cells 121 in series can also be bent and protruded away from the battery cell 121, leaving a space below this part of the metal sheet 124. In the area of the bottom plate 141 facing this part of the metal sheet 124, linear liquid leakage holes 141a can be provided so that the coolant can enter the heat dissipation gap 122 between the corresponding adjacent battery cells 121 through these linear liquid leakage holes 141a.

[0068] Optionally, the specific shape of the liquid leakage hole 141a can be a round hole, an oval hole, a linear hole, an oblong hole, a curved hole, a broken line hole or a through hole of other shapes. When the shape of the liquid leakage hole 141a is a linear hole, its extending direction is generally the same as the extending direction of the heat dissipation gap 122. In this way, the contact area between the coolant flowing out of the liquid leakage hole 141a and the side wall of the battery cell 121 can be increased, and the cooling efficiency can be improved. It can be understood that a circular through hole usually has a higher flow efficiency than a square through hole. When the diameter of the round hole is the same as the short axis of the oval hole and the diameter of the semi-circular part of the oblong hole, due to the larger area of the oval hole and the oblong hole, their flow rates are also larger. When the liquid leakage hole 141a is set as a square hole, the flow efficiency of the coolant passing through the liquid leakage hole 141a can be improved by setting the hole as a square hole with rounded corners and / or chamfering the edge of the hole.

[0069] In still some embodiments, the length of the branch pipe 151 can be extended, and a plurality of second liquid outlet ports 151a can be arranged at intervals on the branch pipe 151 so that the branch pipe 151 can simultaneously transport the coolant to different positions of the liquid storage tank 140, quickly covering the liquid storage tank 140 with the coolant and improving the cooling efficiency.

[0070] The liquid leakage hole 141a facing the heat dissipation gap 122 is arranged opposite to the second liquid outlet port 151a. With such an arrangement, the coolant flowing out of the second liquid outlet port 151a can directly flow to the position where its corresponding liquid leakage hole 141a is located, and then enter the heat dissipation gap 122 from the liquid leakage hole 141a at that place, accurately and quickly achieving heat dissipation.

[0071] In some embodiments, a drainage part (not shown in the figure) is arranged on the side of the edge of the liquid leakage hole 141a facing away from the side plate 142 and facing the heat dissipation gap 122. One end of the drainage part is connected to the edge of the liquid leakage hole 141a, and the other end is connected to the side wall of the battery cell 121. The drainage part is used to drain the coolant flowing out of the liquid leakage hole 141a to the side wall of the battery cell 121. For example, an inclined wall can be arranged on the side of the bottom plate 141 facing away from the side plate 142 and corresponding to the edge of the liquid leakage hole 141a. One end of the inclined wall is connected to the edge of the liquid leakage hole 141a, and the other end is in contact with the side wall of the battery cell 121. When the coolant flows out of the liquid leakage hole 141a, the coolant is affected by the inclined wall, flows along the inclined wall, and then flows from the inclined wall to the side wall of the battery cell 121.

[0072] Optionally, at the position where the inclined wall meets the edge of the liquid leakage hole 141a, an inclined chamfer or a rounded chamfer can be provided, which can better achieve the drainage effect and drain the coolant to the side wall of the battery cell 121.

[0073] In some other embodiments, the edge of the liquid leakage hole 141a facing the heat dissipation gap 122 does not exceed the edge of the side wall of the battery cell 121 in the arrangement direction of the battery cells 121. For example, the edge of the liquid leakage hole 141a can just coincide with the edge of the side wall of the battery cell 121. In this way, the coolant flowing out of the liquid leakage hole 141a can directly flow to the side wall of the battery cell 121. Or, the edge of the liquid leakage hole 141a can expose a part of the edge of the side wall of the battery cell 121. In this way, the coolant can also directly flow onto the side wall of the battery cell 121.

[0074] It can be understood that the above-mentioned liquid leakage holes 141a can also be provided at the positions of the bottom plate 141 opposite to the two side walls of each battery cell 121 parallel to the arrangement direction of the multiple battery cells 121. In this way, the four side walls of the battery cell 121 perpendicular to the bottom plate 141 can all be cooled by the coolant.

[0075] A diversion structure can be provided in the area of the bottom plate 141 near the liquid leakage hole 141a, so as to avoid that in the manufacturing process of the product, due to errors, the part of the bottom plate 141 in the area near the liquid leakage hole 141a hinders the coolant from flowing downward through the liquid leakage hole 141a. For example, the thickness of a part of the area of the bottom plate 141 near the liquid leakage hole 141a can be gradually reduced. Specifically, an inclined chamfer or a rounded chamfer can be provided at the edge of the liquid leakage hole 141a; or, a diversion groove communicating with the liquid leakage hole 141a can also be provided in a part of the area of the bottom plate 141 near the liquid leakage hole 141a. After the coolant enters the diversion groove, it can flow to the liquid leakage hole 141a through the diversion groove.

[0076] The bottom plate 141 can be provided with a plurality of positioning grooves (not shown in the figure). The contour of the positioning grooves matches the contour of the electrodes of the battery cell 121. The positioning grooves are used to cooperate with and position the electrodes of the battery cell 121. When assembling the battery cluster unit 120, the electrodes of the battery cell 121 can be aligned with the positioning grooves and assembled into the positioning grooves. Using the pre-designed positioning grooves for positioning is beneficial to accelerating the assembly of the battery cluster unit 120 and maintaining the consistency of the heat dissipation gap 122.

[0077] Refer to again Figure 3 and Figure 4 . Further, the bottom plate 141 can also be provided with a plurality of pressure relief holes 141b. The pressure relief holes 141b are used to expose the explosion-proof valve 121a at the top of the battery cell 121. In this way, the safety performance of the immersion liquid-cooled energy storage system 100 can be guaranteed.

[0078] In this embodiment, the liquid storage tank 140 can be made of transparent structural plastic and then cured by UV (Ultraviolet), bonding and fixing multiple battery cells 121 to the liquid storage tank 140 to form an integral body. In this way, the liquid storage tank 140 can also fix multiple battery cells.

[0079] In some embodiments, a liquid collection tank (not shown in the figure) can be provided below each battery cluster unit 120, and the battery cluster unit 120 is placed in the liquid collection tank, and the depth of the liquid collection tank is less than the height of the battery cell 121. In this way, when the coolant flows downward from the heat dissipation gap 122, the liquid collection tank can temporarily concentrate the coolant and immerse-cool the bottom surface of the battery cell 121. When there is more coolant, the coolant can overflow from the liquid collection tank and flow to the bottom of the energy storage box 110.

[0080] The immersion liquid-cooled energy storage system of the second embodiment of the present invention is substantially the same as the immersion liquid-cooled energy storage system of the first embodiment. The main difference is that multiple battery cluster units 120 carried on the support member 160 are installed in the outer shell 210, that is, the battery clusters are installed in the outer shell 210, which can be regarded as constituting a battery pack. At this time, it is not necessary to provide a liquid collection tank below the battery cluster unit 120.

[0081] See Figures 8 to 10 , the outer shell 210 includes a second bottom plate 211 and a top plate 212 which are oppositely arranged, and a plurality of second side plates 213 which are sequentially connected end to end and enclose a cylindrical side wall. The second bottom plate 211 and the top plate 212 are respectively connected to the edges of the cylindrical side wall surrounded by the plurality of second side plates 213. With such a setting, when necessary, the coolant conveyed by the cooling pipe 150 can fill the entire internal space of the outer shell 210 to achieve full immersion cooling of multiple battery cluster units 120, which can not only improve the cooling efficiency, but also, when thermal runaway occurs in some battery cluster units 120, avoid the spread of the thermal runaway phenomenon through full immersion.

[0082] See Figure 8 and Figure 9 , in some embodiments, the second bottom plate 211 carrying multiple battery cluster units 120 can be set as a liquid cooling plate, and a cooling flow channel for the coolant to flow through is arranged inside it. An inlet 211a and a third outlet 211b can be arranged at the part where the second bottom plate 211 protrudes from the second side plate 213 to realize the circulation of the coolant on the second bottom plate 211. Setting the second bottom plate 211 as a liquid cooling plate can cool the bottom of the battery cluster unit 120. It can be understood that the cooling flow channel inside the second bottom plate 211 can be set as a serpentine flow channel to improve the cooling effect.

[0083] See Figure 9 、 Figure 11 and Figure 12It can be understood that, since the overall flow direction of the coolant is from top to bottom, the fourth liquid outlet 213a can be set at the lower position of the second side plate 213, and the fourth liquid outlet 213a can discharge the coolant inside the shell 210 to achieve the circulation of the coolant. Alternatively, the fourth liquid outlet 213a can also be set on the second bottom plate 211. Compared with setting the fourth liquid outlet 213a on the lower side of the second side plate 213, setting the fourth liquid outlet 213a on the second bottom plate 211 has a lower horizontal height, which is more conducive to discharging the coolant accumulated in the shell 210 to achieve circulation.

[0084] See again Figure 10 In this embodiment, a cover plate 220 can be provided on the side of the liquid storage tank 140 away from the battery cluster unit 120. The cover plate 220 can limit the position of the wiring harness of the battery cluster unit 120, making the wiring inside the immersion liquid-cooled energy storage system more regular. In addition, the positive and negative electrodes of the battery cluster unit 120 can be indicated on the cover plate 220, which is convenient for operators to accurately connect the circuit inside the system when assembling the immersion liquid-cooled energy storage system.

[0085] The above is a detailed introduction to the immersion liquid-cooled energy storage system provided by the embodiment of the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above implementation methods is only used to help understand the ideas of the present invention. There may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. An immersion liquid-cooled energy storage system, characterized in that: include: Energy storage box; A battery cluster unit is arranged in the energy storage box; A liquid infusion pipe, arranged outside the energy storage box, and used for conveying cooling liquid; A liquid storage tank is arranged in the energy storage box, the liquid storage tank comprises a bottom plate and a plurality of side plates connected to the bottom plate, the bottom plate is fixed to the top of the battery cluster unit and is provided with a plurality of leakage holes; the plurality of side plates are connected end to end in sequence along the edge of the bottom plate and extend in a direction away from the battery cluster unit; at least one of the side plates is provided with at least one overflow port; the overflow port is arranged in a vertical direction, and the diameter of the overflow port gradually decreases from top to bottom; the overflow port is also used as a wiring harness outlet of the battery cluster unit; A cooling pipe is arranged on a side of the liquid storage tank away from the battery cluster unit, one end of the cooling pipe is connected to the liquid delivery pipe, and the other end is arranged opposite to the liquid storage tank, and the cooling pipe is used to transport coolant to the liquid storage tank, and the coolant flows downward through the leakage hole under the action of gravity to cover the surface of the battery cluster unit and cool the battery cluster unit; The battery cluster unit comprises a plurality of battery cells, and a heat dissipation gap is provided between two adjacent battery cells, and the coolant in the liquid storage tank enters the heat dissipation gap through the liquid leakage hole to cool the battery cells; The immersion liquid-cooled energy storage system further includes a liquid outlet pipe disposed at the bottom of the energy storage box, one end of the liquid outlet pipe is connected to the energy storage box and communicates with the internal space of the energy storage box, and the other end is located outside the energy storage box; a valve is disposed at the liquid outlet pipe, and the circulation speed of the coolant is controlled by controlling the flow rate of the valve and the flow rate of the liquid infusion pipe; If there is a thermal runaway of the battery inside the immersion liquid-cooled energy storage system, reduce the valve flow or close the valve, and increase the flow of the liquid infusion tube at the same time, so that the internal space of the energy storage box is completely filled with coolant; The liquid storage tank is bonded and fixed to the multiple battery cells; the bottom plate is provided with multiple positioning grooves, the contours of the positioning grooves match the contours of the electrodes of the battery cells, and the positioning grooves are used to cooperate with the electrodes of the battery cells and perform positioning; the bottom plate is provided with multiple pressure relief holes, and the pressure relief holes are used to expose the explosion-proof valves on the tops of the battery cells.

2. The immersion liquid-cooled energy storage system according to claim 1, characterized in that: It also includes a plurality of support members arranged at intervals along the vertical direction, wherein the plurality of support members are fixed in the energy storage box, and the plurality of battery cluster units are arranged on the support members in a one-to-one correspondence; There are multiple cooling tubes, which are arranged at intervals in the vertical direction. One end of the multiple cooling tubes is connected to the infusion tube, and the other ends of the multiple cooling tubes are arranged opposite to the liquid storage tank in a one-to-one correspondence.

3. The immersion liquid-cooled energy storage system according to claim 1, characterized in that: Each of the cooling tubes has a plurality of branch tubes spaced apart in a horizontal direction, each of the branch tubes has a liquid outlet, and the plurality of branch tubes transport cooling liquid to the corresponding liquid storage tank through the corresponding liquid outlets.

4. The immersion liquid-cooled energy storage system according to claim 3, characterized in that: The liquid outlet is configured such that an inner dimension along a horizontal direction is larger than an inner dimension along a vertical direction.

5. The immersion liquid-cooled energy storage system according to claim 3, characterized in that: The plurality of leakage holes are arranged in an array, and some of the leakage holes are arranged along the extension direction of the heat dissipation gap and face the heat dissipation gap.

6. The immersion liquid-cooled energy storage system according to claim 5, characterized in that: The liquid leakage hole facing the heat dissipation gap is arranged facing the liquid outlet.

7. The immersion liquid-cooled energy storage system according to claim 5, characterized in that: A drainage portion is provided on the edge of the leakage hole facing the heat dissipation gap on the side away from the side plate, one end of the drainage portion is connected to the edge of the leakage hole, and the other end is connected to the side wall of the battery cell. The drainage portion is used to drain the coolant flowing out of the leakage hole to the side wall of the battery cell.

8. The immersion liquid-cooled energy storage system according to claim 5, characterized in that: The edge of the leakage hole facing the heat dissipation gap in the arrangement direction of the battery cells does not exceed the edge of the side wall of the battery cells.

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