A two-phase cooling and heat dissipation energy storage box and refrigerant control method

Abstract

The present application relates to a two-phase cooling and heat dissipation energy storage box and a refrigerant control method, including a box body and a battery group, wherein a liquid accumulation cavity is provided at the bottom of the box body, and a refrigerant medium is contained in the liquid accumulation cavity; the battery group includes a plurality of sequentially arranged battery cells, and a receiving gap is provided between adjacent battery cells; a cooling layer and a gas channel are provided in the receiving gap; the refrigerant medium is sucked by the capillary action of the cooling layer between adjacent battery cells, so that the refrigerant medium covers the surface of the battery cell, and the refrigerant part of the cooling layer is used to evaporate and absorb heat, thereby avoiding excessive temperature increase, and effectively suppressing the heat spread after thermal runaway of the battery cell, so as to meet the safe and reliable operation of the battery cell. It not only improves the heat exchange efficiency of the immersion liquid, but also greatly reduces the amount of liquid used. On the premise of maintaining the ultimate heat dissipation performance of the semi-immersion cooling method, it greatly reduces the cost of the entire energy storage system.

Description

Technical Field

[0001] The present application relates to the field of battery energy storage technology, and in particular to a two-phase cooling and heat dissipation energy storage box and a refrigerant control method. Background Art

[0002] With the rapid development of new energy storage demand, energy storage safety has become a vital part of energy storage projects. In particular, thermal management technology is the top priority of energy storage safety prevention and control. At present, energy storage thermal management mostly adopts two methods: air cooling and liquid cooling. As the charging and discharging rates of energy storage products gradually increase, air cooling solutions can no longer meet the heat dissipation needs of battery cells. Immersion liquid cooling has become a key research direction for battery thermal management needs in the energy storage industry, also known as direct liquid cooling. Immersion liquid cooling refers to directly immersing the battery cell in an insulating, non-toxic, heat-dissipating refrigerant, and taking away the heat through the liquid to achieve a higher level of thermal management. It has the advantages of rapid cooling and good temperature uniformity. In addition to being a temperature control medium, the refrigerant can also be used as a fire-fighting fluid for energy storage systems, combining temperature control and fire protection into one, and achieving long-term safe operation of the energy storage system.

[0003] At present, there are two main types of immersion liquid cooling: TANK cylinder-type full immersion and PACK package full immersion. Among them, the TANK cylinder-type full immersion method has high requirements for the design of the sealing structure, is prone to leakage problems, and requires a large amount of liquid, and the system cost is extremely high. In addition, when the battery cell fails in the later stage, it is necessary to drain the entire liquid and open the cylinder for repair, which has high maintenance requirements and is complicated. The PACK package-level immersion method is relatively convenient to maintain and the difficulty of sealing design is reduced, but it is prone to local hot spots, and the PACK package needs to be pressurized, the manufacturing cost is high, and there is still a large demand for liquid. Summary of the invention

[0004] In order to overcome the above-mentioned deficiencies of the prior art, the present application provides a two-phase cooling and heat dissipation energy storage box and a refrigerant control method, which specifically adopts the following technical solutions:

[0005] A two-phase cooling and heat dissipation energy storage box, comprising a box body and a battery assembly located inside the box body,

[0006] A liquid outlet and a liquid inlet are provided on the side of the box body, a liquid accumulation cavity is provided at the bottom of the box body, and the liquid outlet and the liquid inlet are respectively connected to the liquid accumulation cavity;

[0007] The liquid accumulation cavity contains a cold medium, the battery assembly is partially immersed in the liquid accumulation cavity, and a guide channel for guiding the cold medium is provided between the bottom of the battery assembly and the bottom of the box body;

[0008] The battery assembly includes a plurality of sequentially arranged battery cells, and a receiving gap is provided between adjacent battery cells; a cooling layer and a gas channel are provided in the receiving gap;

[0009] The cooling layer has a capillary structure filled with a refrigerant, one end of the cooling layer is biased toward the bottom of the box and extends below the surface liquid level of the refrigerant in the liquid accumulation cavity, and the other end of the cooling layer is biased toward the top of the box and remains flush with the top surface of the battery cell, and the refrigerant in the liquid accumulation cavity is guided to the upper part of the battery cell through the capillary structure;

[0010] The gas channel is used to discharge the steam generated after the phase change of the cooling medium at the bottom and side of the battery core to the top of the box.

[0011] Optionally: the cooling layer is made of foam metal material, multi-layer metal wire mesh material or organic polymer porous material.

[0012] Optionally, the cooling layer is in the shape of a flat plate, the cooling layer as a whole fills the accommodation gap between adjacent battery cells, and both sides of the cooling layer are respectively in close contact with the side surfaces of the battery cells on the same side.

[0013] Optionally, the cooling layer is in the shape of an elongated strip, a plurality of cooling layers are provided in each accommodating gap, and the plurality of cooling layers are arranged at equal intervals, and the gas channel is provided between adjacent cooling layers.

[0014] Optionally: a support frame is provided in the accommodating gap, the support frame adopts two support bars which are arranged opposite to each other on the sides of the battery cell, and the gas channel is located between the two support bars.

[0015] Optionally, the gas channels and cooling layers are alternately arranged in the accommodation gaps between adjacent battery cells in the battery array.

[0016] Optionally: the liquid inlet is close to the top or bottom of the box, and the liquid inlet is connected to an external liquid inlet pipeline; the liquid outlet is close to the bottom of the box, and the lower edge height of the liquid outlet is higher than or equal to the maximum liquid level height of the liquid accumulation chamber, and the liquid outlet is connected to an external liquid outlet pipeline.

[0017] Optionally: the length of the cooling layer is equal to or greater than the height of the battery cell.

[0018] Optionally: a liquid level meter for monitoring the liquid level of the cold medium in the liquid accumulation chamber is provided inside the box body, and the flow of the cold medium at the liquid outlet and the liquid inlet is controlled by the monitoring signal of the liquid level meter to control the cold medium in the liquid accumulation chamber to maintain a fixed liquid level.

[0019] In addition, the present application also discloses a refrigerant control method for the above energy storage box, which comprises the following steps:

[0020] Obtaining a liquid level signal of the refrigerant medium in the liquid accumulation cavity based on a liquid level meter inside the box; and comparing the obtained liquid level signal with a preset liquid level threshold;

[0021] When the liquid level height signal is lower than the preset liquid level threshold, the flow rate of the refrigerant medium entering the box is increased or the flow rate of the refrigerant medium flowing out of the box is reduced;

[0022] When the liquid level height signal is higher than the preset liquid level threshold, the flow rate of the refrigerant medium entering the box is reduced or the flow rate of the refrigerant medium flowing out of the box is increased;

[0023] When the liquid level height signal is equal to the preset liquid level threshold, the inflow and outflow of the refrigerant medium in the box are kept unchanged.

[0024] Beneficial Effects

[0025] The technical solution of this application has the following beneficial effects:

[0026] (1) The energy storage box of the present application draws the refrigerant medium through the capillary action of the cooling layer between adjacent battery cells, causing the refrigerant medium to flow along the cooling layer and then cover the side surface of the battery cell. When the temperature of the battery cell rises, the refrigerant part of the cooling layer evaporates and absorbs heat, thereby avoiding excessive temperature rise, which can effectively suppress the heat spread after thermal runaway of the battery cell and ensure safe and reliable operation of the battery cell. In addition, only a small amount of refrigerant needs to be stored at the bottom of the box to achieve effective heat dissipation of the battery cell, which not only improves the heat exchange efficiency of the immersion liquid, but also greatly reduces the amount of liquid used. Under the premise of maintaining the ultimate heat dissipation performance of the semi-immersion cooling method, the cost of the entire energy storage system is greatly reduced.

[0027] (2) In the energy storage box of the present application, a gas flow channel is also provided between adjacent battery cells, through which the steam evaporated by the refrigerant medium absorbing heat can be promptly discharged from the battery array, thereby avoiding steam accumulation affecting the capillary action of the cooling layer and indirectly improving the cooling effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the installation structure of the battery group located inside the box in the embodiment of the present application.

[0029] Figure 2 This is a schematic diagram of the cooling layer and gas channel arrangement structure in Example 1 of the present application.

[0030] Figure 3 This is a top view of the cooling layer and gas channel arrangement structure in Example 1 of the present application.

[0031] Figure 4 This is a schematic diagram of the structure of the support frame in Example 1 of the present application.

[0032] Figure 5 This is a schematic diagram of the cooling layer and gas channel arrangement structure in Example 2 of the present application.

[0033] Figure 6 This is a top view of the cooling layer and gas channel arrangement structure in Example 2 of the present application.

[0034] Figure 7 This is a side structural diagram of the cooling layer and gas channel arrangement structure in Example 2 of the present application.

[0035] Figure 8 Schematic diagram of the structure of the energy storage cabinet group in the embodiment of the present application.

[0036] The specific meanings of the reference numerals in the accompanying drawings are:

[0037] 1-box; 101-top of the box; 102-bottom of the box; 103-liquid accumulation chamber; 1031-surface liquid level; 104-first liquid outlet; 105-first liquid inlet; 106-steam outlet; 107-flow guide channel; 2-battery cell; 201-top of the battery cell; 202-bottom of the battery cell; 3-cooling layer; 4-gas channel; 5-accommodating gap; 6-support frame.

[0038] 1-1, energy storage box; 1-2, liquid inlet pipeline; 1-3, liquid return pipeline; 1-4, liquid storage cooling assembly; 1-5, drain valve; 1-6, pressure relief valve; 1-7, energy storage cabinet. DETAILED DESCRIPTION

[0039] The present application is further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and cannot be used to limit the scope of protection of the present application. It should be noted that the following detailed descriptions are all exemplary and are intended to provide further explanation of the present application.

[0040] At present, the cooling method of energy storage boxes generally adopts immersion liquid cooling, that is, the inside of the box is filled with a refrigerant, and the battery cell is placed in a container as a whole or the battery cell package is immersed in the inside of the box, so that the refrigerant medium immerses the battery cell as a whole. This cooling method has high requirements on the sealing structure of the battery cell and a large amount of liquid, and the system cost is extremely high. In addition, when the battery cell fails in the later stage, the maintenance requirements are high and complicated.

[0041] Combination Figure 1 As shown, the embodiment of the present application specifically discloses a two-phase cooling and heat dissipation energy storage box, which includes a box body 1 and a battery group located inside the box body 1.

[0042] The side of the box body 1 is provided with a liquid inlet and a liquid outlet, and the bottom 102 of the box body is provided with a liquid accumulation cavity 103, and the liquid outlet and the liquid inlet are respectively connected to the liquid accumulation cavity 103. Figure 1As shown, in the present application, the side of the box body 1 is provided with a first liquid inlet 105 and a first liquid outlet 104. The external cold medium flows into the box body 1 through the first liquid inlet 105 and accumulates in the liquid accumulation chamber 103. When the cold medium in the liquid accumulation chamber 103 reaches a certain liquid level, the cold medium is discharged to the outside of the box body 1 through the first liquid outlet 104, and is cooled and re-cooled by the subsequent cooling cycle component. The liquid accumulation chamber 103 contains the cold medium, and the battery assembly is partially immersed in the cold medium in the liquid accumulation chamber 103. A guide flow channel 107 for guiding the cold medium is provided between the bottom of the battery assembly and the bottom of the box body. The guide flow channel 107 can ensure that the cold medium at the bottom of the battery assembly continues to flow from the liquid inlet to the liquid outlet, avoiding local temperature accumulation, so as to ensure the reliability of the heat dissipation of the cold medium.

[0043] The battery assembly includes a plurality of sequentially arranged battery cells 2, with a receiving gap 5 between adjacent battery cells 2; in the present application, a cooling layer 3 and a gas channel 4 are provided in the receiving gap 5, wherein the cooling layer 3 is mainly used to draw the cold medium at the bottom 102 of the box body to the upper position of the side of the battery cell 2 through capillary action and absorb heat, and the cold medium flows through the capillary structure of the cooling layer to the top of the battery assembly after boiling phase change, thereby dissipating heat on the side surface of the battery cell 2 to maintain the temperature uniformity of the battery cell 2. The gas channel 4 is used to flow the steam after boiling on the surface of the bottom 202 of the battery cell through the gas channel 4 to the top of the battery cell 2 for discharge.

[0044] Furthermore, the cooling layer 3 described in the present application has a capillary structure filled with a cold medium. It should be noted that the capillary structure of the present application is a structure with micro-sized pores, grooves or channels, which can produce a capillary effect, allowing the liquid to rise or flow therein. The capillary structure can adopt common structures such as porous medium type, groove type or fiber bundle type. The type of capillary structure is not specifically limited in the specific implementation stage and can be selected according to materials, heat dissipation requirements, etc. In the present application, in order to ensure the capillary effect of the cooling layer 3, the cooling layer 3 can adopt a foam metal material, a multilayer metal wire mesh material or an organic polymer porous material.

[0045] For example, a foam metal material is a porous medium-type capillary structure with high porosity, certain strength and rigidity. A porous medium-type capillary structure (such as a foam metal material) is composed of a large number of interconnected tiny pores, such as sponges, foam materials, etc. These pores can be irregularly shaped and distributed in size, and liquids can penetrate and flow in the pores. The rich pore structure greatly increases the specific surface area of ​​the material. At the same time, the foam metal material has good thermal conductivity, and its metal skeleton can quickly transfer heat, while the porous structure of the foam metal increases the heat dissipation area. Heat can be transferred from the metal skeleton to the fluid (such as air or coolant) in the pores. The fluid flows in the pores and takes away the heat, thereby achieving the effect of heat dissipation. For another example, the organic polymer porous material in the present application is also a porous medium-type capillary structure, which uses a material with a certain intrinsic thermal conductivity and can transfer heat through vibration and electron movement on the molecular chain. The porous structure of the material allows a cooling medium (such as air, liquid, etc.) to flow in the pores. When the cooling medium flows through the pores, heat exchange occurs with the surface of the material, taking away the heat, thereby achieving heat dissipation.

[0046] The multi-layer wire mesh material is woven from metal wires. It belongs to a fiber bundle type capillary structure. The fiber bundle type capillary structure is formed by many small fibers gathered together, and the gaps between the fibers constitute a capillary channel. Common ones such as absorbent paper and towels can quickly absorb and conduct moisture, which utilizes the capillary effect between the fiber bundles. In addition, since the metal itself has good thermal conductivity. When heat is transferred to the wire mesh, the heat can be conducted from one layer of wire to another adjacent layer of wire. Through layer-by-layer conduction, the heat can be further rapidly diffused inside the material. At the same time, since the wire mesh has a rich pore structure, when a fluid (such as air or coolant) flows through the wire mesh, the fluid can take away the heat of the wire mesh. The structure of the multi-layer wire mesh increases the contact time and contact area between the fluid and the wire mesh, thereby enhancing the effect of convection heat dissipation.

[0047] The grooved capillary structure is a series of tiny grooves machined on the solid surface. Based on the surface tension of the refrigerant in the grooves, the refrigerant flows along the grooves, thereby transferring heat from the battery cell to the fluid in the grooves, and the heat is taken away by evaporation of the refrigerant.

[0048] One end of the cooling layer is biased toward the bottom 202 of the battery cell and extends below the surface liquid level 1031 of the refrigerant in the liquid accumulation chamber 103, and the other end is biased toward the top 201 of the battery cell and extends to be flush with the surface of the top 201 of the battery cell. The refrigerant in the liquid accumulation chamber 103 can be sucked to the top 201 of the battery cell through the cooling layer; it should be noted that the top 201 of the battery cell in the present application generally refers to the surface of the battery cell 2 facing the top 101 of the box body when the battery cell 2 is located inside the energy storage box body 1; and the bottom 202 of the battery cell generally refers to the surface of the battery cell 2 facing the bottom 102 of the box body when the battery cell 2 is located inside the energy storage box body 1.

[0049] In addition, in the present application, the gas channel 4 is also provided in the accommodation gap 5 , and the gas channel 4 is mainly used to discharge the steam generated after the phase change of the coolant medium at the bottom 202 and the side of the battery cell to the top 101 of the box body.

[0050] Generally, the bottom part of the battery assembly described in this application is immersed below the surface liquid level 1031 of the coolant in the liquid accumulation chamber 103, and the coolant accumulated in the liquid accumulation chamber 103 can always keep the bottom 202 of the battery cell in the battery assembly cool. As for the side surface of the battery cell 2, the coolant in the liquid accumulation chamber 103 is sucked by the capillary action of the cooling layer 3 close to the side surface, so that part of the coolant flows along the cooling layer 3 toward the top 201 of the battery cell. When the temperature of the local position of the side surface of the battery cell 2 is too high, the heat will be transferred to the cooling layer 3 at the position of the side surface of the battery cell 2, heating the coolant in the cooling layer 3, and the coolant absorbs heat and boils to change into steam, and flows along the cooling layer or gas channel 4 to the top 201 of the battery cell and is discharged to the top 101 of the box body.

[0051] It should be noted that, since the bottom 202 of the battery cell in the present application is partially immersed in the cold medium of the liquid accumulation chamber 103, the length of the cooling layer can be kept consistent with the height of the battery cell 2. When the battery cell 2 is partially immersed in the cold medium, the cooling layer 3 located on the side surface of the battery cell 2 will also be partially immersed in the cold medium of the liquid accumulation chamber 103. The cooling layer 3 immersed in the cold medium draws the cold medium toward the unimmersed part, prompting the cold medium in the liquid accumulation chamber 103 to flow toward the top 201 of the battery cell, thereby cooling and dissipating the side surface of the battery cell 2. In addition, the length of the cooling layer 3 can also be longer than the height of the battery cell 2, that is, the bottom of the cooling layer 3 continues to extend downward (that is, in the direction of the bottom 102 of the box body) for a distance, and the capillary effect is enhanced by increasing the immersed area of ​​the cooling layer 3, prompting more cold medium to flow upward, thereby improving the heat dissipation effect.

[0052] Embodiment 1:

[0053] Combination Figure 2-4As shown, the cooling layer 3 in this embodiment 1 is in the shape of a flat plate, and the cooling layer 3 fills the accommodation gap 5 of the adjacent battery cells 2 as a whole, and the two sides of the cooling layer 3 are respectively in close contact with the side surfaces of the battery cells 2 on the same side. Figure 2 As shown, the side surface of each cooling layer 3 will cover the side surface of the battery cell 2 as a whole. When the refrigerant enters the capillary structure of the cooling layer 3 through capillary action, the refrigerant will cover the entire side surface of the battery cell 2 from bottom to top. When the refrigerant is heated and boils and evaporates, the steam will be discharged upward along the pores into the space 101 at the top of the box.

[0054] Since the bottom of the battery cell 2 also generates heat when it is working, after the bottom 202 of the battery cell transfers heat to the coolant medium, the coolant medium located at the bottom 202 of the battery cell is heated and boiled to generate steam. In order to prevent the steam at the bottom 202 of the battery cell from entering the capillary structure of the cooling layer 3 and affecting its capillary action, a support frame 6 is further provided in the accommodating gap 5 in this embodiment 1. Figure 4 As shown, the support frame 6 uses two support bars arranged opposite to each other on the sides of the battery cell 2, and the gas channel 4 is located between the two support bars. On the one hand, the support frame 6 can physically support the battery cell 2, and on the other hand, the gas channel 4 located in the middle of the support frame 6 can provide a flow path for the steam at the bottom 202 of the battery cell to avoid the accumulation of steam at the bottom 202 of the battery cell, which affects the flow of the coolant medium into the cooling layer 3.

[0055] Further, combined with Figure 2 and Figure 3 As shown, the gas channels 4 and cooling layers 3 in this embodiment 1 are alternately arranged in the accommodation gaps 5 of adjacent battery cells 2 in the battery assembly. That is, one side of the battery cell 2 is in close contact with the cooling layer 3, and the other side of the battery cell 2 is in close contact with the gas channels 4. Figure 2 As shown, when the cold medium is accumulated inside the liquid accumulation cavity 103, the cold medium will be distributed on the side surface of the battery cell 2 through the capillary action of the internal pores of the cooling layer 3. When the battery cell 2 is working or thermal runaway occurs, causing the internal temperature to rise, the heat inside the battery cell 2 is transferred to the surface of the battery cell 2 shell. The heat on the surface of the battery cell 2 shell heats the cold medium at the bottom 202 of the battery cell and the cooling layer 3, wherein the cold medium at the cooling layer 3 is heated and boiled into steam, and is discharged through the pores at the top of the cooling layer 3; and the cold medium at the bottom 202 of the battery cell is heated and boiled, and steam bubbles are generated and accumulated at the bottom 202 of the battery cell, and flow to the position of the gas channel 4, and discharged to the top 101 of the box through the gas channel 4. The arrangement of the gas channel 4 and the cooling layer 3 in this embodiment can keep one side of each battery cell 2 at a uniform temperature and discharge steam on the other side.

[0056] Embodiment 2:

[0057] Combination Figure 5-7As shown, the cooling layer 3 in this embodiment 2 is in the shape of an elongated strip, and a plurality of cooling layers 3 are arranged in each accommodating gap 5, and the plurality of cooling layers 3 are arranged at equal intervals, and the gas channel 4 is arranged between adjacent cooling layers 3, as shown in FIG. Figure 7 As shown. It should be noted that the number of cooling layers 3 and the width of the gas channel 4 in this embodiment 2 are not specifically limited. Generally, the more cooling layers 3 are arranged, the better the heat dissipation effect on the side surface of the battery cell 2; and the wider the gas channel 4, the better the steam exhaust effect. In the actual arrangement process, adaptive adjustments can be made according to the heat dissipation requirements and exhaust requirements of the battery cell 2.

[0058] Combination Figure 5 As shown, when the liquid accumulation cavity 103 is filled with cold medium, the cold medium will be distributed on the surfaces of both sides of the battery cell 2 through the capillary action of the internal pores of the cooling layer 3. When the battery cell 2 is working or thermal runaway occurs, causing the internal temperature to rise, the heat inside the battery cell 2 is transferred to the surface of the battery cell 2 shell. The heat on the surface of the battery cell 2 shell heats the cold medium at the bottom 202 of the battery cell and the cooling layer 3, wherein the cold medium at the cooling layer 3 is heated and boiled into steam, and is discharged through the pores on the upper part of the cooling layer 3 and the adjacent gas channel 4; and the cold medium at the bottom 202 of the battery cell is heated and boiled, generating steam bubbles and accumulating at the bottom 202 of the battery cell, and flowing to the gas channel 4 on both sides of the battery cell 2, and discharged to the top 101 of the box through the gas channel 4. The arrangement of the gas channel 4 and the cooling layer 3 in this embodiment 2 allows both sides of each battery cell 2 to be cooled by the cold medium to maintain a uniform temperature and to discharge steam.

[0059] It should be emphasized that the arrangement of the embodiment 1 and the embodiment 2 of the present application will generate a large amount of steam inside the box 1 and accumulate at the top 101 of the box, so a steam outlet 106 can be provided at the top 101 of the box. Figure 1 As shown, the steam outlet 106 is connected to an external condensing device, which is used to re-liquefy the steam of the refrigerant into a liquid refrigerant. When a large amount of steam accumulates on the top 101 of the box body, the external condensing device can be activated to extract the steam on the top 101 of the box body and re-liquefy it into a refrigerant, thereby preventing the large amount of steam from accumulating and affecting the capillary effect of the cooling layer 3.

[0060] It should be noted that the locations of the liquid inlet and the liquid outlet as well as the flow control described in the present application must ensure that a certain level of refrigerant is always stored in the liquid storage cavity 103 at the bottom 102 of the box body.

[0061] As a layout method of liquid inlet and liquid outlet in the present application, the top 101 of the box body is provided with a first liquid inlet 105, and the bottom 102 of the box body is provided with a first liquid outlet 104 connected to an external liquid return pipeline. The box body 1 in the present application can be provided with at least one first liquid outlet 104, and the first liquid outlet 104 is arranged on a side surface of the box body 1 near the bottom, and the lower edge height of the first liquid outlet 104 is higher than or equal to the maximum liquid level height of the liquid accumulation chamber 103. One end of the first liquid inlet 105 is connected to an external liquid inlet pipeline, and the other end of the first liquid inlet 105 extends into the box body 1 and is connected to the diversion liquid inlet device. The refrigerant located in the external liquid inlet pipeline is passed into the box body 1 of the energy storage box through the first liquid inlet 105. The diversion liquid inlet device is provided with a refrigerant outlet. The refrigerant is distributed above the battery cell 2 through the refrigerant outlet of the diversion liquid inlet device. The refrigerant distributed to the top 201 of the battery cell can dissipate heat from the top 201 of the battery cell. Then, the refrigerant flows downward from the side of the battery cell 2 due to gravitational potential energy, thereby cooling the side surface of the battery cell 2 and finally gathering in the liquid accumulation cavity 103 at the bottom 102 of the box body. Furthermore, the shunt liquid inlet device described in the present application includes a liquid inlet manifold and at least one shunt branch pipe, wherein the liquid inlet manifold mainly distributes the refrigerant medium from the outside to multiple shunt branches evenly. Preferably, in the present application, a shunt branch pipe is respectively provided at the upper position of each battery group corresponding to the top 101 of the box body, and the shunt branch pipe is provided with a refrigerant outlet at the position corresponding to each battery cell 2; multiple shunt branches are connected to the same liquid inlet manifold, and the liquid inlet manifold is connected to the liquid inlet pipeline outside the box body 1 through the first liquid inlet 105. It should be noted that the number of shunt branches in the present application is not limited, and each battery group can be provided with one shunt branch pipe or multiple shunt branches; or two battery groups can share one shunt branch pipe. The number and distribution position of the shunt branches in the present application can be adjusted based on the internal structure of the energy storage box and the refrigerant flow requirements.

[0062] It should be noted that the layout of the above-mentioned liquid inlet and outlet in the present application can efficiently dissipate heat when the battery group is working. When the energy storage box stops running, the cold medium in the liquid accumulation cavity 103 is sucked to the side surface of the battery cell 2 through the cooling layer 3. Once the battery cell 2 has thermal runaway and causes the surface temperature to rise, the cold medium in the cooling layer 3 can dissipate heat for the battery cell 2 in time.

[0063] Or as another layout of the liquid inlet and outlet in this application, such as Figure 1As shown, the bottom 102 of the box body is provided with a first liquid inlet 105 and a first liquid outlet 104, and the first liquid outlet 104 and the first liquid inlet 105 are both arranged at a side of the box body 1 near the bottom, and the lower edge height of the first liquid outlet 104 is higher than or equal to the maximum liquid level height of the liquid accumulation cavity 103; the first liquid inlet 105 is connected to the external liquid inlet pipeline, and the first liquid outlet 104 is connected to the external liquid return pipeline. With this layout, when the battery is assembled, it is only necessary to ensure that the cold medium in the liquid accumulation cavity 103 at the bottom 102 of the box body is at a certain liquid level, and the capillary action of the cooling layer 3 is used to automatically draw the cold medium to the side surface of the battery cell 2 to dissipate heat. To ensure that the refrigerant medium in the liquid accumulation chamber 103 at the bottom 102 of the box body is at a fixed liquid level, a liquid level gauge can be set in the liquid accumulation chamber 103 to control the amount of refrigerant entering the first liquid inlet 105 and the amount of refrigerant flowing out of the first liquid outlet 104 to ensure that the liquid level in the liquid accumulation chamber 103 is fixed.

[0064] Furthermore, the present application may also be provided with a second liquid inlet at the top 101 of the box, wherein one end of the second liquid inlet is connected to an external liquid inlet pipeline, and the other end of the second liquid inlet extends into the box 1 and is connected to a fire-fighting liquid inlet device; a first solenoid valve is provided between the second liquid inlet and the liquid inlet pipeline, and the opening and closing state of the first solenoid valve controls the flow of refrigerant to the fire-fighting liquid inlet device. It should be understood that in the present application, the refrigerant medium through the liquid accumulation cavity 103 and the cooling layer 3 can evenly cover the surface of the battery cell 2 to perform overflow heat exchange, realize cooling and heat dissipation of the battery cell 2, and also play a fire-fighting function. Once the thermal runaway intensifies and the internal temperature of the energy storage box increases sharply, the energy storage box of the present application will open the first solenoid valve, and at this time a large amount of refrigerant will enter the interior of the box 1 through the fire-fighting liquid inlet device, so that the interior of the box 1 changes from a semi-immersed mode to a fully immersed mode, thereby performing fire control on the out-of-control battery cell 2, further improving the safety of the energy storage box.

[0065] Furthermore, the present application may also provide a second solenoid valve at the first liquid outlet 104, and a level gauge for monitoring the liquid level of the refrigerant in the liquid accumulation chamber 103 is provided inside the housing 1, and the opening and closing state of the second solenoid valve is controlled by the monitoring signal of the level gauge. It should be understood that, since the bottom 202 of the battery cell needs to be kept immersed in the refrigerant medium of the liquid accumulation chamber 103 to ensure heat dissipation, and to avoid excessive accumulation of refrigerant inside the housing 1, the liquid level of the liquid accumulation chamber 103 can be monitored by a level gauge, and a liquid level threshold is set. Once the actual liquid level of the liquid accumulation chamber 103 exceeds the set liquid level threshold, the opening of the second solenoid valve is increased, and the flow rate of the first liquid outlet 104 is increased, so that the liquid level of the liquid accumulation chamber 103 drops below the liquid level threshold, thereby ensuring that only a small amount of refrigerant is accumulated in the housing 1, which greatly reduces the amount of liquid used and effectively controls the overall operating weight of the device to reduce deployment and installation requirements.

[0066] In addition, the present application also discloses an energy storage cabinet group, combined with Figure 8 As shown, it includes the energy storage box 1-1, the liquid inlet pipeline 1-2, the liquid return pipeline 1-3, the liquid storage cooling assembly 1-4 and the energy storage cabinet 1-7 as in the above-mentioned embodiment, wherein the energy storage box 1-1, the liquid inlet pipeline 1-2, the liquid return pipeline 1-3, the liquid storage cooling assembly 1-4 are all installed in the energy storage cabinet 1-7, wherein a plurality of the energy storage boxes 1-1 are stacked, and the energy storage box 1-1 and the liquid storage cooling assembly 1-4 are connected through the liquid inlet pipeline 1-2 and the liquid return pipeline 1-3 to form a cooling circulation loop. The liquid storage cooling assembly 1-4 in the present application generally includes a liquid storage tank, a refrigeration module, a circulating pump and an electric heater, wherein the refrigerant is stored in the liquid storage tank, and the cooling module cools the refrigerant in the liquid storage tank through a cooling medium. The liquid storage tank is provided with at least three liquid outlets, one of which is connected to the liquid inlet pipeline after being connected to the circulation pump and the electric heater in sequence. The circulation pump is used to provide driving force for the flow of the refrigerant, and the electric heater is used to control the refrigerant in the liquid inlet pipeline to maintain a constant temperature. Another liquid outlet of the liquid storage tank is connected to the return liquid pipeline, which is used to recycle the refrigerant in the return liquid pipeline. The liquid storage tank is also provided with a liquid outlet for discharging the refrigerant. Generally, the drain valve 1-5 corresponding to this position is closed. When the refrigerant is replaced, the drain valve 1-5 can be opened to empty the liquid inside the liquid storage tank and re-introduce new refrigerant. In order to avoid excessive internal pressure in the liquid storage cabinet group, a pressure relief valve can also be set on the return liquid pipeline 1-3, and the internal pressure can be reduced by the pressure relief valve to promote the smooth flow of the refrigerant.

[0067] Furthermore, the present application also discloses a refrigerant control method for the above energy storage box, which comprises the following steps:

[0068] Based on the liquid level meter inside the box body 1, a liquid level height signal of the refrigerant medium in the liquid accumulation chamber 103 is obtained; and the obtained liquid level height signal is compared with a preset liquid level threshold;

[0069] When the liquid level height signal is lower than the preset liquid level threshold, the flow rate of the refrigerant medium entering the box 1 is increased or the flow rate of the refrigerant medium flowing out of the box 1 is reduced;

[0070] When the liquid level height signal is higher than the preset liquid level threshold, the flow rate of the refrigerant medium entering the box 1 is reduced or the flow rate of the refrigerant medium flowing out of the box 1 is increased;

[0071] When the liquid level height signal is equal to the preset liquid level threshold, the inflow and outflow of the refrigerant in the box 1 are kept unchanged.

[0072] The above control method can ensure that the liquid level of the coolant in the liquid accumulation chamber 103 is kept within a fixed range, thereby preventing the liquid level fluctuation in the liquid accumulation chamber 103 from affecting the effect of the capillary action in the cooling layer.

[0073] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A two-phase cooling and heat dissipation energy storage box, characterized in that: It includes a box body and a battery assembly located inside the box body. A liquid outlet and a liquid inlet are provided on the side of the box body, a liquid accumulation cavity is provided at the bottom of the box body, and the liquid outlet and the liquid inlet are respectively connected to the liquid accumulation cavity; the liquid inlet is close to the top or the bottom of the box body, and the liquid inlet is connected to an external liquid inlet pipeline; the liquid outlet is close to the bottom of the box body, and the lower edge height of the liquid outlet is higher than or equal to the maximum liquid level height of the liquid accumulation cavity, and the liquid outlet is connected to an external liquid outlet pipeline; The liquid accumulation cavity contains a cold medium, the battery assembly is partially immersed in the liquid accumulation cavity, and a guide channel for guiding the cold medium is provided between the bottom of the battery assembly and the bottom of the box body; A steam outlet is provided on the top of the box body, and the steam outlet is connected to an external condensing device, through which the steam of the refrigerant medium is reliquefied into a liquid refrigerant; The battery assembly includes a plurality of sequentially arranged battery cells, and a receiving gap is provided between adjacent battery cells; a cooling layer and a gas channel are provided in the receiving gap; The cooling layer has a capillary structure filled with a refrigerant, one end of the cooling layer is biased toward the bottom of the box and extends below the surface liquid level of the refrigerant in the liquid accumulation cavity, and the other end of the cooling layer is biased toward the top of the box and remains flush with the top surface of the battery cell, and the refrigerant in the liquid accumulation cavity is guided to the upper part of the battery cell through the capillary structure; The gas channel is used to discharge the steam generated by the phase change of the refrigerant medium at the bottom and sides of the battery cell to the top of the box; A level gauge for monitoring the liquid level of the refrigerant medium in the liquid accumulation cavity is provided inside the box body. The flow of the refrigerant medium at the liquid outlet and the liquid inlet is controlled by the monitoring signal of the level gauge to control the refrigerant medium in the liquid accumulation cavity to maintain a fixed liquid level. Obtaining a liquid level signal of the refrigerant medium in the liquid accumulation cavity based on a liquid level meter inside the box; and comparing the obtained liquid level signal with a preset liquid level threshold; When the liquid level height signal is lower than the preset liquid level threshold, the flow rate of the refrigerant medium entering the box is increased or the flow rate of the refrigerant medium flowing out of the box is reduced; When the liquid level height signal is higher than the preset liquid level threshold, the flow rate of the refrigerant medium entering the box is reduced or the flow rate of the refrigerant medium flowing out of the box is increased; When the liquid level height signal is equal to the preset liquid level threshold, the inflow and outflow of the refrigerant medium in the box are kept unchanged.

2. The energy storage box according to claim 1, characterized in that: The cooling layer is made of foam metal material, multi-layer metal wire mesh material or organic polymer porous material.

3. The energy storage box according to claim 1, characterized in that: The cooling layer is in a flat plate shape, and the cooling layer as a whole fills the accommodation gap between adjacent battery cells, and two sides of the cooling layer are respectively in close contact with the side surfaces of the battery cells on the same side.

4. The energy storage box according to claim 1, characterized in that: The cooling layer is in the shape of an elongated strip. A plurality of cooling layers are arranged in each accommodating gap, and the plurality of cooling layers are arranged at equal intervals. The gas channels are arranged between adjacent cooling layers.

5. The energy storage box according to claim 3, characterized in that: A support frame is provided in the accommodating gap. The support frame adopts two support bars which are arranged opposite to each other on the sides of the battery core. The gas channel is located between the two support bars.

6. The energy storage box according to claim 5, characterized in that: The gas channels and cooling layers are alternately arranged in the accommodation gaps between adjacent battery cells in the battery assembly.

7. The energy storage box according to claim 1, characterized in that: The length of the cooling layer is equal to or greater than the height of the battery core.

8. A refrigerant control method for the energy storage box according to any one of claims 1 to 7, characterized in that: The steps include: Obtaining a liquid level signal of the refrigerant medium in the liquid accumulation cavity based on a liquid level meter inside the box; and comparing the obtained liquid level signal with a preset liquid level threshold; When the liquid level height signal is lower than the preset liquid level threshold, the flow rate of the refrigerant medium entering the box is increased or the flow rate of the refrigerant medium flowing out of the box is reduced; When the liquid level height signal is higher than the preset liquid level threshold, the flow rate of the refrigerant medium entering the box is reduced or the flow rate of the refrigerant medium flowing out of the box is increased; When the liquid level height signal is equal to the preset liquid level threshold, the inflow and outflow of the refrigerant medium in the box are kept unchanged.

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