Two-phase cooling battery group and energy storage box

Abstract

The utility model relates to a two-phase cooling battery group and an energy storage box, the battery group comprises a plurality of battery cells which are arranged in sequence, and a containing gap is arranged between every two adjacent battery cells; a cooling layer and a gas channel are arranged in the accommodating gap; the capillary action of the cooling layer between the adjacent battery cells sucks the refrigerant medium, so that the refrigerant medium covers the surfaces of the battery cells, and the refrigerant part of the cooling layer is evaporated to absorb heat, thereby avoiding excessive temperature rise, effectively inhibiting heat spread after thermal runaway of the battery cells, and satisfying safe and reliable operation of the battery cells. Meanwhile, the gas flow channels are also arranged between the adjacent battery cells, and steam evaporated by heat absorption of the refrigerant medium can be discharged into the battery group in time through the gas flow channels, so that the capillary action of the cooling layer can be prevented from being influenced by steam accumulation, and the cooling effect is indirectly improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of battery energy storage, in particular to a two-phase cooling and heat dissipation battery grouping and energy storage box. BACKGROUND

[0002] With the rapid development of new energy storage demand, energy storage safety has become a crucial part of energy storage projects. In particular, thermal management technology is the top priority in the prevention and control of energy storage safety. At present, energy storage thermal management mainly adopts air cooling and liquid cooling. With the gradual increase of the charging and discharging rate of energy storage products, the air cooling scheme cannot meet the heat dissipation needs of the battery. Immersion liquid cooling, also known as direct liquid cooling, has become the focus of research in the battery thermal management of the energy storage industry. Immersion liquid cooling refers to directly immersing the battery in an insulating, non-toxic and heat-dissipating coolant, which can take away heat through the liquid to achieve higher-level thermal management. It has the advantages of rapid cooling and good uniformity. In addition to being used as a temperature control medium, the coolant can also be used as a fire-fighting liquid for the energy storage system, combining temperature control and fire-fighting into one, and realizing long-term safe operation of the energy storage system.

[0003] At present, immersion liquid cooling mainly includes TANK cylinder full immersion and PACK package full immersion. The TANK cylinder full immersion method has high requirements for the design of the sealing structure and is prone to leakage. In addition, a large amount of liquid is required, and the system cost is extremely high. Moreover, when maintaining the battery in the later stage, the entire liquid needs to be drained before the cylinder is opened for maintenance, which is complicated and requires high maintenance. The PACK package immersion method is relatively convenient to maintain and has a lower sealing design difficulty, but it is prone to local hot spots. In addition, the PACK package needs to withstand pressure, which increases the manufacturing cost and still requires a large amount of liquid. CONTENT OF THE INVENTION

[0004] In order to overcome the shortcomings of the prior art, the application provides a two-phase cooling and heat dissipation battery grouping and energy storage box, which specifically adopts the following technical solutions:

[0005] A two-phase cooling and heat dissipation battery grouping, which comprises a plurality of sequentially arranged battery cells, and a containing gap is arranged between adjacent battery cells; a cooling layer and a gas channel are arranged in the containing gap;

[0006] The cooling layer has a capillary structure filled with coolant medium, one end of the cooling layer extends to the bottom surface of the battery cell in the direction of the bottom of the battery cell, and the other end of the cooling layer extends in the direction of the top of the battery cell and is flush with the top surface of the battery cell. The capillary structure guides the coolant medium at the bottom of the battery cell to the upper part of the battery cell; and the gas channel is used for discharging the steam generated after the phase change of the coolant medium at the bottom and sides of the battery cell.

[0007] Optionally, the cooling layer is flat, the cooling layer fills the accommodation gap of the adjacent battery cell, and the cooling layer is tightly attached to the side surface of the battery cell on the same side.

[0008] Optionally, the cooling layer is in the shape of an elongated strip, a plurality of cooling layers are arranged in each accommodation gap, and the plurality of cooling layers are arranged at equal intervals, and the gas channel is arranged between the adjacent cooling layers.

[0009] Optionally, a support frame is arranged in the accommodation gap, the support frame comprises two support strips arranged opposite to the side of the battery cell, and the gas channel is arranged between the two support strips.

[0010] Optionally, the gas channel and the cooling layer are alternately arranged in the accommodation gap of the adjacent battery cell in the battery group.

[0011] Optionally, the length of the cooling layer is equal to or greater than the height of the battery cell.

[0012] Optionally, the cooling layer is made of any one of a foamed metal material, a multi-layer metal wire mesh material, or an organic polymer porous material.

[0013] In addition, the application also discloses a two-phase cooling and heat dissipation energy storage box, which is characterized by comprising a box body and the battery group as described above; the bottom of the box body is provided with a liquid accumulation cavity, the liquid accumulation cavity contains refrigerant medium, and the battery group is partially immersed in the liquid accumulation cavity.

[0014] Optionally, the top or bottom of the side of the box body is provided with a liquid inlet, the bottom of the side of the box body is provided with a liquid outlet, the liquid outlet and the liquid inlet are in communication with the liquid accumulation cavity, the lower edge of the liquid outlet is higher than or equal to the maximum liquid level of the liquid accumulation cavity, and the top of the box body is provided with a steam outlet which is in communication with an external condensing device, so that the steam of the refrigerant medium is liquefied into liquid refrigerant medium by the condensing device.

[0015] Optionally, the inside of the box body is provided with a liquid level meter for monitoring the liquid level of the refrigerant medium in the liquid accumulation cavity, the flow of the refrigerant medium of the liquid inlet and the liquid outlet is controlled by the monitoring signal of the liquid level meter, and the liquid level of the refrigerant medium in the liquid accumulation cavity is kept constant.

[0016] Advantages

[0017] The technical scheme of the application has the following advantages:

[0018] (1) The battery group of the present application can suck the refrigerant medium through the capillary action of the cooling layer between adjacent battery cells, so that the refrigerant medium flows along the cooling layer, and then covers 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, effectively inhibiting the spread of heat after the thermal runaway of the battery cell, and meeting the safe and reliable operation of the battery cell.

[0019] (2) The battery group of the present application can effectively cool the battery cell by storing a small amount of refrigerant at the bottom of the energy storage box, which not only improves the efficiency of the immersed liquid heat exchange, but also greatly reduces the amount of liquid. Under the premise of maintaining the extreme heat dissipation performance of the semi-immersed cooling mode, the cost of the entire energy storage system is greatly reduced.

[0020] (3) The battery group of the present application is also provided with a gas flow channel between adjacent battery cells. The steam generated by the heat absorption and evaporation of the refrigerant medium can be discharged from the battery group in time through the gas flow channel, which can avoid the accumulation of steam affecting the capillary action of the cooling layer, and indirectly improve the cooling effect. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The figure is a schematic diagram of the installation structure of the battery group in the embodiment of the present application.

[0022] Figure 2 The figure is a schematic diagram of the cooling layer and gas channel arrangement structure in embodiment 1 of the present application.

[0023] Figure 3 The figure is a schematic diagram of the cooling layer and gas channel arrangement structure in embodiment 1 of the present application.

[0024] Figure 4 The figure is a schematic diagram of the support frame in embodiment 1 of the present application.

[0025] Figure 5 The figure is a schematic diagram of the cooling layer and gas channel arrangement structure in embodiment 2 of the present application.

[0026] Figure 6 The figure is a schematic diagram of the cooling layer and gas channel arrangement structure in embodiment 2 of the present application.

[0027] Figure 7 The figure is a schematic diagram of the cooling layer and gas channel arrangement structure in embodiment 2 of the present application.

[0028] The specific meaning of the reference signs in the drawings is as follows:

[0029] 1-Box body; 101-Box body top; 102-Box body bottom; 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-Battery cell top; 202-Battery cell bottom; 3-Cooling layer; 4-Gas channel; 5-Accommodation gap; 6-Support frame. Detailed Implementation

[0030] The present application will now be further described with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application and should not be construed as limiting the scope of protection of the present application. It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present application.

[0031] Currently, the cooling method for energy storage boxes is generally immersion liquid cooling, which involves filling the inside of the box with a cooling medium, placing the entire battery cell behind the container or immersing the battery cell pack inside the box so that the cooling medium completely submerges the battery cell. This cooling method has high requirements for the battery cell sealing structure, requires a large amount of liquid, and has an extremely high system cost. In addition, maintenance is required to be high and complicated when the battery cell fails.

[0032] Combination Figure 1 As shown in the embodiment, this application specifically discloses a two-phase cooling and heat dissipation battery pack, which is configured inside the housing 1 of the energy storage box.

[0033] The battery pack includes multiple sequentially arranged battery cells 2, with a receiving gap 5 between adjacent battery cells 2. In this application, a cooling layer 3 and a gas channel 4 are provided within the receiving gap 5. The cooling layer 3 is mainly used to draw the cold medium from the bottom 202 of the battery cell (i.e., the cold medium in the liquid accumulation chamber 103 of the housing 1) to the upper part of the side of the battery cell 2 through capillary action and absorb heat. After the cold medium boils and undergoes a phase change, it flows through the capillary structure of the cooling layer to the top of the battery pack and is discharged, thereby dissipating heat from 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 allow the vapor after boiling on the surface of the bottom 202 of the battery cell to flow through the gas channel 4 to the top of the battery cell 2 and be discharged.

[0034] Furthermore, the cooling layer 3 described in this application has a capillary structure filled with a cooling medium. It should be noted that the capillary structure described in this application is a structure with tiny pores, grooves, or channels, capable of generating capillary action, allowing the liquid to rise or flow within it. The capillary structure can employ common structures such as porous media type, groove type, or fiber bundle type. In specific implementation stages, the type of capillary structure is not specifically limited and can be selected based on materials, heat dissipation requirements, etc. In this application, to ensure the capillary action of the cooling layer 3, the cooling layer 3 can be made of one of the following: foamed metal material, multilayer metal mesh material, or organic polymer porous material.

[0035] For example, foamed metal materials are porous capillary structures with high porosity and certain strength and stiffness. Porous capillary structures (such as foamed metal materials) are composed of a large number of interconnected micropores, such as sponges and foam materials. These pores can be irregularly shaped and sized, allowing liquids to permeate and flow within them. The abundant pore structure greatly increases the specific surface area of ​​the material. Simultaneously, foamed metal materials have good thermal conductivity; their metal skeleton can rapidly transfer heat, while the porous structure increases the heat dissipation area. Heat can be transferred from the metal skeleton to the fluid (such as air or coolant) within the pores. The fluid flows through the pores, carrying away the heat, thus achieving heat dissipation. Another example is the organic polymer porous material in this application, which is also a porous capillary structure. It uses materials with a certain intrinsic thermal conductivity, capable of transferring heat through vibrations and electron movement in the molecular chains. The porous structure of the material allows cooling media (such as air or liquid) to flow within the pores. When the cooling medium flows through the pores, it exchanges heat with the material surface, carrying away the heat, thus achieving heat dissipation.

[0036] Multi-layered metal mesh materials are woven from metal wires, forming a fiber bundle capillary structure. This structure consists of numerous tiny fibers clustered together, with the gaps between the fibers creating capillary channels. Common examples include absorbent paper and towels, whose fibrous structures allow for rapid absorption and conduction of moisture, utilizing the capillary action between fiber bundles. Furthermore, metal itself has excellent thermal conductivity. When heat is transferred to the metal mesh, it can be conducted from one layer of wire to the next, achieving rapid heat diffusion within the material through layer-by-layer conduction. Simultaneously, the abundant porosity of the metal mesh allows fluids (such as air or coolant) to carry away heat from the mesh as they flow through it. The multi-layered structure increases the contact time and area between the fluid and the mesh, thus enhancing convective heat dissipation.

[0037] The grooved capillary structure is made by processing a series of tiny grooves on the solid surface. Based on the surface tension of the cold medium located in the groove, the cold medium flows along the direction of the groove, thereby transferring heat from the battery cell to the fluid in the groove. Heat is absorbed and removed through the evaporation of the cold medium.

[0038] Furthermore, the energy storage box described in this application has a liquid inlet and a liquid outlet on its side, and a liquid accumulation chamber 103 on its bottom 102. The liquid outlet and the liquid inlet are respectively connected to the liquid accumulation chamber 103. Figure 1As shown, in this application, the side of the housing 1 is provided with a first liquid inlet 105 and a first liquid outlet 104. The external cooling medium flows into the housing 1 through the first liquid inlet 105 and accumulates in the liquid accumulation chamber 103. When the cooling medium in the liquid accumulation chamber 103 reaches a certain level, the cooling medium is discharged to the outside of the housing 1 through the first liquid outlet 104 and then cooled and recooled by the subsequent cooling circulation components. The liquid accumulation chamber 103 contains the cooling medium, and the battery pack is immersed in the cooling medium in the liquid accumulation chamber 103. A guide channel 107 for guiding the cooling medium is provided between the bottom of the battery pack and the bottom 102 of the housing. The guide channel 107 can ensure that the cooling medium at the bottom of the battery pack continuously flows from the liquid inlet to the liquid outlet, avoiding local temperature accumulation and ensuring the reliability of cooling medium heat dissipation.

[0039] One end of the cooling layer 3 is biased towards the bottom 202 of the battery cell (equivalent to biased towards the bottom 102 of the housing) and extends below the surface liquid level 1031 of the cooling medium in the liquid accumulation chamber 103. The other end is biased towards the top 201 of the battery cell (equivalent to biased towards the top 101 of the housing) and extends flush with the surface of the top 201 of the battery cell. The cooling layer 3 can draw the cooling medium from the liquid accumulation chamber 103 to the top 201 of the battery cell. It should be noted that in this application, the top 201 of the battery cell generally refers to the surface of the battery cell 2 facing the top 101 of the housing when the battery cell 2 is located inside the energy storage housing 1; while the bottom 202 of the battery cell generally refers to the surface of the battery cell 2 facing the bottom 102 of the housing when the battery cell 2 is located inside the energy storage housing 1.

[0040] In addition, the gas channel 4 is provided in the accommodating gap 5 in this application. The gas channel 4 is mainly used to discharge the vapor generated after the phase change of the cold medium at the bottom 202 and the side of the battery cell to the top 101 of the housing.

[0041] Generally, the bottom portion of the battery pack described in this application is submerged below the surface liquid level 1031 of the cooling medium in the liquid accumulation chamber 103. The cooling medium accumulated in the liquid accumulation chamber 103 can always maintain heat dissipation for the bottom 202 of the battery cells in the battery pack. For the side surface of the battery cell 2, the cooling medium in the liquid accumulation chamber 103 is drawn in by the capillary action of the cooling layer 3 that is in close contact with the side surface, so that some of the cooling medium flows along the cooling layer 3 towards the top 201 of the battery cell. When the temperature of a local location on the side surface of the battery cell 2 is too high, the heat will be transferred to the cooling layer 3 at the side surface of the battery cell 2, heating the cooling medium in the cooling layer 3. After absorbing heat, the cooling medium boils and changes into vapor, which flows along the cooling layer or the gas channel 4 to the top 201 of the battery cell and is discharged to the top 101 of the casing.

[0042] It should be noted that, since the bottom 202 of the battery cell is partially immersed in the cooling medium of the liquid accumulation chamber 103 in this application, the length of the cooling layer can be consistent with the height of the battery cell 2. When the battery cell 2 is partially immersed in the cooling medium, the cooling layer 3 located on the side surface of the battery cell 2 will also be partially immersed in the cooling medium of the liquid accumulation chamber 103. The cooling layer 3 immersed in the cooling medium draws the cooling medium to the unimmersed part, causing the cooling medium in the liquid accumulation chamber 103 to flow towards the top 201 of the battery cell, thereby cooling and dissipating heat from 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 extends downward (i.e., towards the bottom 102 of the casing) for a certain distance. By increasing the immersion area of ​​the cooling layer 3, the capillary effect is enhanced, causing more cooling medium to flow upward, thereby improving the heat dissipation effect.

[0043] Example 1:

[0044] Combination Figures 2-4 As shown, in this embodiment 1, the cooling layer 3 is flat, and the cooling layer 3 completely fills the accommodating gap 5 between adjacent battery cells 2, with both sides of the cooling layer 3 tightly attached to the side surface of the battery cell 2 on the same side. Figure 2 As shown, the side surface of each cooling layer 3 will completely cover the side surface of the battery cell 2. When the cooling medium enters the capillary structure of the cooling layer 3 through capillary action, the cooling medium will cover the entire side surface of the battery cell 2 from bottom to top. When the cooling medium is heated and boils and evaporates, the steam will be discharged upward along the pores into the space at the top of the box 101.

[0045] Since the bottom of the battery cell 2 also generates heat during operation, after the bottom 202 of the battery cell transfers heat to the cooling medium, the cooling medium located at the bottom 202 of the battery cell is heated and boils to generate steam. 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, this embodiment 1 also provides a support frame 6 within the receiving gap 5. Figure 4 As shown, the support frame 6 uses two support bars arranged opposite to each other on the side 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 provide physical support for 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 vapor at the bottom of the battery cell 202, avoiding the accumulation of vapor at the bottom of the battery cell 202 and affecting the flow of the cold medium into the cooling layer 3.

[0046] Furthermore, in combination Figure 2 and Figure 3 As shown, in this embodiment 1, the gas channel 4 and the cooling layer 3 are alternately arranged within the accommodating gap 5 of adjacent cells 2 in the battery pack. That is, one side of the cell 2 is in close contact with the cooling layer 3, while the other side of the cell 2 is in close contact with the gas channel 4. Figure 2As shown, when a cooling medium accumulates inside the liquid accumulation chamber 103, the cooling medium is distributed to the side surface of the battery cell 2 through capillary action in the pores inside the cooling layer 3. When the battery cell 2 is working or experiences thermal runaway, causing its internal temperature to rise, the heat inside the battery cell 2 is conducted to the surface of the battery cell 2 shell. The heat on the surface of the battery cell 2 shell heats the cooling medium at the bottom 202 of the battery cell and in the cooling layer 3. The cooling medium in the cooling layer 3 is heated and boils into steam, which is discharged through the pores in the upper part of the cooling layer 3. The cooling medium at the bottom 202 of the battery cell, after being heated and boiling, generates steam bubbles that accumulate at the bottom 202 of the battery cell and flow towards the gas channel 4, and is discharged to the top 101 of the housing through the gas channel 4. In this embodiment, the arrangement of the gas channel 4 and the cooling layer 3 allows one side of each battery cell 2 to maintain a uniform temperature, while the other side discharges steam.

[0047] Example 2:

[0048] Combination Figures 5-7 As shown, in this embodiment 2, the cooling layer 3 is elongated and narrow, with multiple cooling layers 3 arranged at equal intervals within each accommodating gap 5. Gas channels 4 are provided between adjacent cooling layers 3. Figure 7 As shown. It should be noted that the number of cooling layers 3 and the width of the gas channels 4 in this embodiment 2 are not specifically limited. Generally, the more cooling layers 3 there are, the better the heat dissipation effect on the side surface of the battery cell 2; and the wider the gas channels 4, the better the steam exhaust effect. In actual arrangement, adjustments can be made according to the heat dissipation and exhaust requirements of the battery cell 2.

[0049] Combination Figure 5 As shown, when a cooling medium accumulates inside the liquid accumulation chamber 103, the cooling medium is distributed to both sides of the battery cell 2 through capillary action in the pores inside the cooling layer 3. When the battery cell 2 is working or experiences thermal runaway, causing its internal temperature to rise, the heat inside the battery cell 2 is conducted to the surface of the battery cell 2 shell. The heat on the surface of the battery cell 2 shell heats the cooling medium at the bottom 202 of the battery cell and in the cooling layer 3. The cooling medium in the cooling layer 3 is heated and boils into steam, which is discharged through the pores in the upper part of the cooling layer 3 and the adjacent gas channel 4. The cooling medium at the bottom 202 of the battery cell, after being heated and boiling, generates steam bubbles that accumulate at the bottom 202 of the battery cell and flow to the gas channels 4 on both sides of the battery cell 2, and is discharged to the top 101 of the housing through the gas channels 4. The arrangement of the gas channels 4 and the cooling layer 3 in this embodiment 2 allows each battery cell 2 to maintain a uniform temperature by being cooled by the cooling medium on both sides, while also allowing steam to be discharged.

[0050] It should be emphasized that the arrangement in both Embodiment 1 and Embodiment 2 of this application will generate a large amount of steam inside the box 1 and accumulate at the top 101 of the box. Therefore, a steam outlet 106 can be provided at the top 101 of the box, such as... Figure 1As shown, the steam outlet 106 is connected to an external condensing device, which is used to reliquefy the vapor of the cooling medium back into a liquid state. When a large amount of steam accumulates on the top 101 of the housing, the external condensing device can be activated to extract the steam from the top 101 of the housing and reliquefy it back into a cooling medium, thereby preventing the large accumulation of steam from affecting the capillary effect of the cooling layer 3.

[0051] It should be noted that the location of the liquid inlet and outlet and the flow control described in this application must ensure that the liquid accumulation chamber 103 at the bottom of the box 102 always has a certain level of cold medium.

[0052] As one arrangement of the inlet and outlet in this application, the top 101 of the box is provided with a first inlet 105, and the bottom 102 of the box is provided with a first outlet 104 connected to an external return pipeline. In this application, the box 1 may be provided with at least one first outlet 104. The first outlet 104 is located on one side of the box 1 near the bottom, and the lower edge of the first 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 pipe, and the other end of the first liquid inlet 105 extends into the housing 1 and is connected to the diversion liquid inlet device. The refrigerant located in the external liquid inlet pipe is introduced into the housing 1 of the energy storage tank 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. Subsequently, the refrigerant flows downward from the side of the battery cell 2 by gravity potential energy, thereby cooling the side surface of the battery cell 2, and finally collects in the liquid accumulation chamber 103 at the bottom 102 of the housing. Furthermore, the liquid inlet device described in this application includes an inlet manifold and at least one branch pipe. The inlet manifold primarily distributes the external refrigerant evenly into multiple branch pipes. Preferably, in this application, a branch pipe is provided above each battery pack on the top 101 of the housing, and each branch pipe has a refrigerant outlet corresponding to each cell 2. Multiple branch pipes are connected to the same inlet manifold, which is connected to the external liquid inlet pipeline of the housing 1 via a first inlet 105. It should be noted that the number of branch pipes is not limited in this application. Each battery pack can have one or more branch pipes; alternatively, two battery packs can share one branch pipe. The number and distribution of branch pipes in this application can be adjusted based on the internal structure of the energy storage tank and the refrigerant flow requirements.

[0053] It should be noted that the layout of the liquid inlet and outlet in this application can achieve efficient heat dissipation when the battery pack is working. When the energy storage box stops running, the cooling medium in the liquid accumulation chamber 103 is drawn to the side surface of the cell 2 through the cooling layer 3. Once the cell 2 experiences thermal runaway and the surface temperature rises, the cooling medium in the cooling layer 3 can dissipate heat from the cell 2 in a timely manner.

[0054] Alternatively, as another arrangement of the inlet and outlet in this application, such as Figure 1 As shown, the bottom 102 of the housing is provided with a first liquid inlet 105 and a first liquid outlet 104, and both the first liquid outlet 104 and the first liquid inlet 105 are located on one side of the housing 1 near the bottom. The lower edge of the first liquid outlet 104 is higher than or equal to the maximum liquid level of the liquid accumulation chamber 103. The first liquid inlet 105 is connected to an external liquid inlet pipe, and the first liquid outlet 104 is connected to an external liquid return pipe. With this layout, during battery assembly, it is only necessary to ensure that the cooling medium in the liquid accumulation chamber 103 at the bottom 102 of the housing is at a certain liquid level. The capillary action of the cooling layer 3 will automatically draw in the cooling medium to dissipate heat to the side surface of the battery cell 2. To ensure that the refrigerant in the liquid accumulation chamber 103 at the bottom of the box is at a fixed liquid level, a level gauge can be installed in the liquid accumulation chamber 103. The level gauge can be used to control the amount of refrigerant entering through the first inlet 105 and the amount of refrigerant flowing out through the first outlet 104, so as to ensure that the liquid level in the liquid accumulation chamber 103 is fixed.

[0055] Furthermore, this application may also provide a second liquid inlet at the top 101 of the housing, wherein one end of the second liquid inlet is connected to an external liquid inlet pipe, and the other end of the second liquid inlet extends into the housing 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 pipe, and the flow of refrigerant to the fire-fighting liquid inlet device is controlled by the opening and closing state of the first solenoid valve. It should be understood that in this application, the refrigerant medium through the liquid accumulation chamber 103 and the cooling layer 3 can uniformly cover the surface of the battery cell 2 to achieve overflow heat exchange, realize the cooling and heat dissipation of the battery cell 2, and also serve a fire-fighting function. Once thermal runaway intensifies and the internal temperature of the energy storage tank increases sharply, the energy storage tank of this application will open the first solenoid valve. At this time, a large amount of refrigerant will enter the interior of the housing 1 through the fire-fighting liquid inlet device, changing the interior of the housing 1 from a semi-immersed state to a fully immersed state, thereby providing fire-fighting control for the runaway battery cell 2 and further improving the safety of the energy storage tank.

[0056] Furthermore, this application may also provide a second solenoid valve at the first liquid outlet 104, and a level gauge is provided inside the housing 1 to monitor the liquid level of the refrigerant in the liquid accumulation chamber 103. 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 it is necessary to keep the bottom 202 of the battery cell submerged in the refrigerant in 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 the level gauge, and a liquid level threshold can be set. Once the actual liquid level in the liquid accumulation chamber 103 exceeds the set liquid level threshold, the opening of the second solenoid valve is increased, the flow rate of the first liquid outlet 104 is increased, and the liquid level in the liquid accumulation chamber 103 drops below the liquid level threshold, thereby ensuring that only a small amount of refrigerant accumulates in the housing 1, significantly reducing the amount of liquid used, effectively controlling the overall operating weight of the device, and reducing deployment and installation requirements.

[0057] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A battery pack with two-phase cooling and heat dissipation, characterized in that, The battery pack includes multiple cells arranged in sequence, with a receiving gap between adjacent cells; the receiving gap contains a cooling layer and a gas channel; The cooling layer has a capillary structure filled with a cooling medium. One end of the cooling layer extends towards the bottom of the cell to the bottom surface of the cell, and the other end extends towards the top of the cell and remains flush with the top surface of the cell. The capillary structure guides the cooling medium at the bottom of the cell to the upper part of the cell. The gas channel is used to discharge the vapor generated after the phase change of the cooling medium at the bottom and sides of the cell.

2. The battery pack according to claim 1, characterized in that, The cooling layer is flat and fills the gap between adjacent cells. Both sides of the cooling layer are in close contact with the side surface of the cells on the same side.

3. The battery pack according to claim 1, characterized in that, The cooling layer is elongated and narrow, with multiple cooling layers arranged at equal intervals in each accommodating gap, and gas channels provided between adjacent cooling layers.

4. The battery pack according to claim 2, characterized in that, A support frame is provided within the accommodating gap. The support frame consists of two support bars arranged opposite to each other on the side of the battery cell, and the gas channel is located between the two support bars.

5. The battery pack according to claim 4, characterized in that, The gas channels and cooling layers are alternately arranged within the accommodating gaps between adjacent cells in the battery pack.

6. The battery pack according to claim 1, characterized in that, The length of the cooling layer is equal to or greater than the height of the battery cell.

7. The battery pack according to claim 1, characterized in that, The cooling layer is made of any one of the following materials: foamed metal material, multilayer metal mesh material, or organic polymer porous material.

8. A two-phase cooling energy storage box, characterized in that, The device includes a housing and a battery pack as described in any one of claims 1-7; the bottom of the housing is provided with a liquid accumulation chamber, the liquid accumulation chamber contains a cooling medium, and the battery pack is partially immersed in the liquid accumulation chamber.

9. The energy storage box according to claim 8, characterized in that, The box body has a liquid inlet at the top or bottom of the side and a liquid outlet at the bottom of the side. The liquid inlet and the liquid outlet are connected to the liquid accumulation chamber, and the lower edge of the liquid outlet is higher than or equal to the maximum liquid level of the liquid accumulation chamber. The box body has a steam outlet at the top, which is connected to an external condensing device. The condensing device liquefies the vapor of the refrigerant back into a liquid form.

10. The energy storage box according to claim 9, characterized in that, The box is equipped with a level gauge for monitoring the liquid level of the cold medium in the liquid accumulation chamber. The flow of the cold medium at the outlet and inlet is controlled by the monitoring signal of the level gauge, so as to maintain a fixed liquid level of the cold medium in the liquid accumulation chamber.

Images