Lithium battery liquid cooling fire fighting system and fire fighting method

Abstract

The invention relates to the technical field of lithium battery thermal management, in particular to a lithium battery liquid cooling fire fighting system and method.The lithium battery liquid cooling fire fighting system comprises a liquid cooling plate, a temperature sensor, a water inlet pipe, a water outlet pipe, a circulating pump, a cooling liquid box and a control device, and the liquid cooling plate comprises a liquid cooling plate body and two liquid cooling carriers; the two liquid cooling carriers and the two cover plates are connected to form two cavities, the water inlet end of the liquid cooling flow channel and the anti-explosion valve are located in one cavity, the water outlet end of the liquid cooling flow channel is located in the other cavity, the liquid cooling carriers are provided with water nozzle assemblies, the water inlet pipe is provided with a pressure sensor, and the pressure sensor is electrically connected with the control device; when thermal runaway occurs, the control device closes the water inlet pipe of the battery cell which works normally and pressurizes the cooling liquid, and the cooling liquid enters the battery cell through the position of the anti-explosion valve of the thermal runaway battery cell for fire fighting. The liquid cooling system and the fire extinguishing system are effectively combined, so that the production cost of the lithium battery is reduced, and the production and assembly of the lithium battery are simplified.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery thermal management, and in particular to a lithium battery liquid cooling fire fighting system and a fire fighting method. Background Art

[0002] Lithium batteries generate heat during use, causing the battery temperature to rise. When lithium batteries are used in a colder environment, the battery temperature will be lower. Too high or too low battery temperature will affect the electrochemical performance and safety of the battery. Therefore, a thermal management system is required to ensure that the battery operates within the optimal operating temperature range through reasonable cooling or heating measures. Battery thermal runaway is a major safety issue of common concern in the battery industry. Once thermal runaway occurs, it will not only cause fire and explosion, but also trigger a chain reaction, affecting the entire battery module and system. Therefore, existing batteries are also equipped with a fire protection system to play a fire protection role when thermal runaway occurs.

[0003] At present, the mainstream thermal management system is to set up a liquid cooling structure such as a liquid cooling plate at the bottom of the battery cell to cool the battery cell by heat transfer. However, the heat needs to pass through the bottom liquid cooling plate, structural glue, battery cell insulation layer, battery cell insulation film, battery cell shell and other media before being transferred to the inside of the battery cell, and the thermal conductivity rate is low. In order to increase the thermal conduction rate, the existing technology often fills the battery pack with thermal conductive silica gel and other materials, but while the thermal conductivity rate is increased, the heat dissipation rate is also increased. During the cooling process, the thermal management system also dissipates heat to the outside through the structural parts of the battery pack, resulting in the loss and waste of heat sources and low heat utilization. In addition, the thermal management method at the bottom of the battery cell will also cause a large temperature difference between the upper and lower positions of the battery cell, and the overall temperature consistency of the battery cell is poor.

[0004] At present, the common fire protection system is to wrap fireproof and heat-insulating materials between battery cells to prevent the spread of heat, or to set up an independent fire extinguishing structure. After thermal runaway occurs, the fire extinguishing structure will be activated and spray fire extinguishing agent to the battery cell with thermal runaway. However, the fire extinguishing structure will only be triggered when the battery has thermal runaway and is detected by the fire protection system. The existing fire protection system has the defect of delayed response, and cannot directly reach the inside of the battery cell, and cannot directly prevent chemical reactions. It is a passive fire protection mechanism. More importantly, the thermal management system and the fire protection system are designed independently, which is costly, space-intensive, and inconvenient to produce.

[0005] Therefore, it is urgently needed to be improved. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, the present invention provides a lithium battery liquid cooling fire fighting system and a fire fighting method.

[0007] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0008] On the one hand, the present invention proposes a lithium battery liquid cooling fire protection system, comprising a liquid cooling plate, a temperature sensor, a water inlet pipe, a water outlet pipe, a circulating pump, a coolant tank and a control device, wherein the liquid cooling plate comprises a liquid cooling plate body and two liquid cooling carriers, the liquid cooling plate body is located in each battery cell and is provided with a liquid cooling flow channel, the two liquid cooling carriers are respectively fixed on two cover plates and are respectively used to connect the water inlet pipe and the water outlet pipe, the coolant tank is connected to the water inlet pipe through the circulating pump, the temperature sensor is arranged on the surface of the battery cell, an explosion-proof valve is arranged on one cover plate of the battery cell, the control device is electrically connected to the temperature sensor and the circulating pump respectively, two liquid cooling carriers are fixedly connected to the two cover plates to form two cavities, the water inlet end of the liquid cooling flow channel and the explosion-proof valve are located in one of the cavities, and the water outlet end of the liquid cooling flow channel is located in the other cavity, a water nozzle assembly is arranged on the liquid cooling carrier, a pressure sensor with a function of disconnecting the water inlet pipe is arranged on the water inlet pipe, and the pressure sensor is electrically connected to the control device.

[0009] Preferably, the liquid-cooling carrier includes: an independently designed liquid-cooling carrier cover plate and a liquid-cooling carrier body, the liquid-cooling carrier body is a fully enclosed structure with openings at both ends, the liquid-cooling carrier cover plate is fixedly connected to an open end of the liquid-cooling carrier body, the other open end of the liquid-cooling carrier body has the water inlet end and the explosion-proof valve cover arranged inside and is fixedly connected to the cover plate, and the faucet assembly is arranged on the liquid-cooling carrier cover plate.

[0010] Preferably, the liquid-cooling carrier cover plate includes an integrally formed first cover plate and a second cover plate, the first cover plate is a strip-shaped structure and the length matches the water inlet end; the liquid-cooling carrier body comprises a first cavity and a second cavity that are connected, the first cover plate matches the top structure of the first cavity, and the second cover plate matches the top structure of the second cavity.

[0011] Preferably, a through groove and an explosion-proof valve installation groove are provided on the cover plate adjacent to the water inlet end, the water inlet end is exposed through the through groove, a connecting part is fixed on the cover plate, the connecting part is partially hollowed out to form a third cavity and a fourth cavity, the third cavity is located at the outer periphery of the notch of the through groove, and the fourth cavity is located at the outer periphery of the notch of the explosion-proof valve installation groove; a first boss and a second boss are sequentially provided on the inner side surface of the liquid-cooling carrier body from top to bottom, the first boss matches the liquid-cooling carrier cover plate structure, and the connecting part matches the second boss structure.

[0012] Preferably, the lower surface of the liquid-cooling carrier cover plate is fixedly connected to the upper surface of the first boss, and the inner side surface of the second boss is fixedly connected to the outer side surface of the connecting portion.

[0013] Preferably, the connecting portion and the cover plate are integrally formed, and the first boss, the second boss and the liquid-cooling carrier body are integrally formed.

[0014] Preferably, the faucet assembly is arranged in the middle of the first cover plate.

[0015] Preferably, the corners of the long strip structure are transitioned by arcs, and the second cover plate is a runway-type structure.

[0016] Preferably, the first cover plate and the second cover plate are in a T-shaped structure.

[0017] On the other hand, the present invention also proposes a lithium battery fire fighting method, which adopts the above-mentioned lithium battery liquid cooling fire fighting system. When thermal runaway occurs, the control device acts on the pressure sensor to close the water inlet pipe of the normally working battery cell, and at the same time acts on the circulating pump to pressurize the coolant. The coolant enters the thermal runaway battery cell through the explosion-proof valve position to play a fire fighting role.

[0018] Compared with the prior art, the present invention makes simple, scientific and reasonable improvements to the liquid cooling plate, connects the water inlet end of the liquid cooling channel with the explosion-proof valve. When thermal runaway occurs, the explosion-proof valve is opened actively or passively, and the coolant can be used as a fire extinguishing agent to directly enter the thermally runaway battery cell from the explosion-proof valve to cool it, thereby playing a fire-fighting role from the source; more importantly, the present invention effectively combines the liquid cooling system and the fire-fighting system, which not only reduces the production cost of lithium batteries, but also simplifies the production and assembly of lithium batteries, which helps to further improve the production efficiency of lithium batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 This is an implementation of the lithium battery liquid cooling fire protection system proposed by the present invention;

[0021] Figure 2 for Figure 1 The main view;

[0022] Figure 3 for Figure 1 Schematic diagram of the structure of the liquid cooling carrier;

[0023] Figure 4 for Figure 3 A schematic diagram of the enlarged structure at A in the middle;

[0024] Figure 5 for Figure 3 Schematic diagram of the three-dimensional structure of the liquid cooling carrier body;

[0025] Figure 6 for Figure 1 Schematic diagram of the structure of the middle cover;

[0026] Figure 7 for Figure 1 Schematic diagram of the connection between the middle cover plate and the liquid cooling carrier body.

[0027] In the figure: 1. battery cell; 2. liquid-cooling carrier; 21. liquid-cooling carrier cover; 211. first cover; 212. second cover; 213. nozzle assembly; 22. liquid-cooling carrier body; 221. upper end surface of liquid-cooling carrier body; 222. first boss; 223. second boss; 224. lower end surface of liquid-cooling carrier body; 225. first cavity; 226. second cavity; 3. water inlet pipe; 4. water outlet; 5. cover; 51. connecting part; 511. third cavity; 512. fourth cavity; 6. pressure sensor. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0029] It should be noted that the components or structures not described in detail below all adopt conventional technical means in the art, and those skilled in the art can use them in combination without creative work.

[0030] like Figure 1-Figure 7 Commonly shown: a lithium battery liquid cooling fire protection system, including a liquid cooling plate, a temperature sensor, a water inlet pipe 3, a water outlet pipe, a circulating pump, a coolant tank and a control device, the liquid cooling plate includes a liquid cooling plate body and two liquid cooling carriers 3, the liquid cooling plate body is located in each battery cell 1 and is provided with a liquid cooling flow channel, the two liquid cooling carriers 2 are respectively fixed on two cover plates 5 and are respectively used to connect the water inlet pipe 3 and the water outlet pipe, the coolant tank is connected to the water inlet pipe 3 through the circulating pump, the temperature sensor is arranged on the surface of the battery cell 1, and the battery cell 1 is provided with an explosion-proof valve, the control device is electrically connected to the temperature sensor and the circulating pump respectively, two liquid-cooling carriers 2 are fixedly connected to the two cover plates 5 to form two cavities, the water inlet end of the liquid-cooling flow channel and the explosion-proof valve are located in one of the cavities, and the water outlet end of the liquid-cooling flow channel is located in the other cavity, a nozzle assembly 213 is provided on the liquid-cooling carrier 2, and a pressure sensor 6 with a function of disconnecting the water inlet pipe 3 is provided on the water inlet pipe 3, and the pressure sensor 6 is electrically connected to the control device.

[0031] Liquid cooling principle: Generally speaking, the working pressure of the coolant pipeline does not exceed 350KPa, and the opening pressure of the explosion-proof valve is at least 600KPa, so the liquid cooling plate can play a normal liquid cooling function without accidentally triggering the explosion-proof valve. When the battery cell 1 works normally, the coolant in the coolant tank is delivered to the water inlet pipe 3 through the circulation pump, then enters the cavity and enters the body of the liquid cooling plate through the water inlet end of the liquid cooling channel, and finally flows out from the water outlet end of the liquid cooling channel and discharges the battery cell 1 from the water outlet pipe. In this process, the pressure sensor 6 can monitor the pressure of the coolant and transmit it to the control device. The control device can adjust the coolant pressure within an appropriate range by acting on the circulation pump according to the liquid cooling needs to improve the liquid cooling effect while ensuring that the explosion-proof valve will not be triggered; during the circulation of the coolant, the battery cell 1 is cooled or heated (the coolant temperature can be flexibly adjusted, and adjusting to a higher temperature can achieve heating of the battery cell 1 to meet the requirement of controlling the temperature of the battery cell 1 within a better working temperature range when the ambient temperature is low).

[0032] Firefighting principle: When a battery cell 1 experiences thermal runaway, the explosion-proof valve opens, and the coolant can flow into the battery cell 1 through the explosion-proof valve, preventing the chemical reaction from continuing, directly blocking the thermal runaway, and playing a firefighting role from the source.

[0033] Compared with the prior art, the lithium battery liquid cooling fire fighting system proposed in the present invention has at least the following beneficial effects:

[0034] (1) The liquid cooling system also has a fire-fighting function, which realizes the combination and unification of the liquid cooling system and the fire-fighting system, can effectively reduce the production cost of lithium batteries and simplify the assembly operation;

[0035] (2) The fire-fighting function is responsive, accurate and efficient, and can directly act on the inside of the battery cell, blocking the chemical reaction at the root, thus achieving active fire-fighting;

[0036] (3) Thermal management of the battery cell is performed from within to achieve uniform cooling or heating of the battery cell, which can effectively improve the consistency of the overall temperature of the battery cell.

[0037] As a preferred technical solution, in another embodiment of the present invention, the liquid-cooling carrier includes: a liquid-cooling carrier cover plate 21 and a liquid-cooling carrier body 22 which are independently designed and made of the same material, the liquid-cooling carrier body 22 being a fully enclosed structure with openings at both ends, the liquid-cooling carrier cover plate 21 being fixedly connected to an open end of the liquid-cooling carrier body 22, the other open end of the liquid-cooling carrier body 22 having the water inlet end and the explosion-proof valve cover arranged therein being fixedly connected to the cover plate 5, and the faucet assembly 213 being arranged on the liquid-cooling carrier cover plate 21.

[0038] In this embodiment, the liquid cooling carrier cover plate 21 and the liquid cooling carrier body 22 are independently designed structures. The liquid cooling carrier cover plate 21 is covered on the top of the liquid cooling carrier body 22, and the bottom of the liquid cooling carrier body 22 is connected to the cover plate 5. The independently designed structure facilitates the installation of the liquid cooling carrier and can ensure the accuracy of the installation position and the stability and firmness after installation. Of course, the liquid cooling carrier cover plate 21 and the liquid cooling carrier body 22 can also be designed as an integrated structure.

[0039] It should be noted that:

[0040] The water nozzle assembly 213 is a prior art, and any water nozzle assembly that can be installed on the liquid cooling carrier cover plate 21 and connected to the cooling liquid pipeline can be used in the present invention.

[0041] The faucet assembly 213 is disposed on the liquid-cooling carrier cover plate 21 , preferably away from the explosion-proof valve to prevent the explosion-proof valve from causing pressure shock to the faucet assembly 213 when the explosion-proof valve is opened, thereby preventing the faucet assembly 213 from being damaged.

[0042] The liquid cooling carrier cover plate 21 and the liquid cooling carrier body 22 are preferably made of the same metal material.

[0043] As a preferred technical solution, in another embodiment of the present invention, the liquid-cooled carrier cover plate 21 includes a first cover plate 211 and a second cover plate 212, the first cover plate 211 is a strip-shaped structure and the length matches the water inlet end; the liquid-cooled carrier body 22 comprises a first cavity 225 and a second cavity 226 that are connected, the first cover plate 211 matches the top structure of the first cavity 225, and the second cover plate 212 matches the top structure of the second cavity 226.

[0044] In this embodiment, the first cover plate 211 is designed as a long strip structure and its length matches the water inlet end, mainly to form a flat water inlet cavity, namely the first cavity 225, which matches the length of the water inlet end. The coolant enters the first cavity 225 through the nozzle assembly 213 and is buffered by the first cavity 225 and then distributed relatively evenly to each liquid cooling channel, thereby more effectively reducing the temperature of each part of the battery cell 1 and achieving the purpose of uniform heat dissipation of the battery cell 1.

[0045] In this embodiment, the second cavity 226 is an explosion-proof valve accommodating cavity. On the one hand, it can buffer the pressure shock when the explosion-proof valve opens at the moment of thermal runaway. On the other hand, it is connected with the first cavity 225, so that the coolant can flow into it immediately after thermal runaway and enter the battery cell 1 through the explosion-proof valve, quickly preventing the chemical reaction from occurring and achieving the purpose of fire fighting.

[0046] As a preferred technical solution, in another embodiment of the present invention, a through groove and an explosion-proof valve installation groove are provided on the cover plate 5 adjacent to the water inlet end, the water inlet end is exposed through the through groove, a connecting portion 51 is fixed on the cover plate 5, and the connecting portion 51 is partially hollowed out to form a third cavity 511 and a fourth cavity 512, the third cavity 511 is located at the outer periphery of the notch of the through groove, and the fourth cavity 512 is located at the outer periphery of the notch of the explosion-proof valve installation groove; the inner side surface of the liquid-cooled carrier body 22 is sequentially provided with a first boss 222 and a second boss 223 from top to bottom, the first boss 222 is structurally matched with the liquid-cooled carrier cover plate 21, and the connecting portion 51 is structurally matched with the second boss 223; the liquid-cooled carrier body 22 includes an upper end face 221 of the liquid-cooled carrier body and a lower end face 224 of the liquid-cooled carrier body.

[0047] In this embodiment, the first boss 222 is located on the inner side of the liquid-cooled carrier body 22 close to the upper end surface 221 of the liquid-cooled carrier body. The first boss 222 is designed to facilitate reliable connection between the liquid-cooled carrier body 22 and the liquid-cooled carrier cover plate 21 through a laser seam welding process.

[0048] In this embodiment, the second boss 223 is located on the inner side surface of the liquid-cooling carrier body 22 close to the lower end surface 224 of the liquid-cooling carrier body; a connecting portion 51 is fixed on the cover plate 5; the design of the second boss 223 and the connecting portion 51 is to facilitate the liquid-cooling carrier body 22 and the cover plate 5 to achieve reliable connection through a laser seam welding process.

[0049] In this embodiment, the third cavity 511 and the fourth cavity 512 are not connected to ensure that the connecting portion 51 has a good supporting effect, so that after the connecting portion 51 is welded with the second boss 223, it can play a good positioning and supporting role for the liquid-cooled carrier body 22, thereby avoiding deformation of the liquid-cooled carrier body 22 and causing adverse effects on liquid cooling, fire fighting, etc.

[0050] As a preferred technical solution, in another embodiment of the present invention, the lower surface of the liquid-cooled carrier cover plate 21 is fixedly connected to the upper surface of the first boss 222. After the connection, the outer surface of the liquid-cooled carrier cover plate 21 remains flush with the upper end surface 221 of the liquid-cooled carrier body; the inner side surface of the second boss 223 is fixedly connected to the outer side surface of the connecting portion 51.

[0051] As a preferred technical solution, in another embodiment of the present invention, the first boss 222, the second boss 223 and the liquid-cooling carrier body 22 are integrally formed and made of the same material, and the connecting portion 51 and the cover plate 5 are integrally formed and made of the same material.

[0052] The first boss 222, the second boss 223, and the liquid cooling carrier body 22 are an integrated structure, which is not only easy to process, but also helps to provide appropriate support pressure for related connection components to ensure the connection strength and sealing after welding. In addition, in order to further improve the connection strength, stability and sealing effect after welding, the height of the first boss 222 and the second boss 223 is preferably 1-1.5 mm, especially 3-8 mm. Within this height range, it can withstand the thermal stress and mechanical stress during the welding process without occupying too much liquid inlet space.

[0053] The connecting portion 51 and the cover plate 5 are an integrated structure, which is convenient for processing and for fixing the liquid cooling carrier 2 and the cover plate 5 , thereby ensuring the connection strength and sealing after welding.

[0054] As a preferred technical solution, in another embodiment of the present invention, the corners of the elongated structure are transitioned by arcs, the second cover plate 212 matches the explosion-proof valve structure, and is preferably designed as a runway-type structure, wherein the elongated structure and the runway-type structure are an integrated T-shaped structure.

[0055] In this embodiment, the corners of the long strip structure are arc-shaped, and even the edge of the long strip structure is a semicircular structure, which is convenient for welding operation and helps to increase the contact area with the liquid cooling carrier body 22, thereby increasing the welding area and further improving the strength and stability after welding. The second cover plate 212 is designed as a runway structure for the same consideration.

[0056] As a preferred technical solution, in another embodiment of the present invention, the faucet assembly 213 is disposed in the middle of the first cover plate 211 .

[0057] The faucet assembly 213 is disposed in the middle of the first cover plate 211, which has the following advantages:

[0058] (1) It helps to form a more uniform flow distribution of the coolant at the water inlet end of the liquid cooling plate, thereby more effectively absorbing and removing the heat generated by the battery cell 1, helping to reduce the temperature gradient of the battery cell 1 and improving the overall heat dissipation efficiency.

[0059] (2) It can reduce flow resistance. The coolant can enter from the middle of the first cover plate 211 and flow in two directions, i.e., both ends. Compared with the flow in a single direction, it can reduce flow resistance to a certain extent and reduce the pressure drop consumption of the coolant.

[0060] (3) Improve space utilization. The faucet assembly 213 is designed in the middle of the first cover plate 211, which can more flexibly adapt to the layout requirements of the battery pack and improve the space utilization when grouping.

[0061] (4) The position of the explosion-proof valve is staggered to avoid the pressure impact on the water inlet pipe 3 when the explosion-proof valve is opened after thermal runaway, which helps to protect the water inlet pipe 3 and prevent it from being damaged and leaking.

[0062] The fire fighting method of the above-mentioned lithium battery liquid cooling fire fighting system is specifically as follows: when thermal runaway occurs, the control device acts on the pressure sensor to close the water inlet pipe of the normally working battery cell, and at the same time acts on the circulating pump to pressurize the coolant, and the coolant enters the thermal runaway battery cell through the explosion-proof valve position to play a fire fighting role.

[0063] Generally speaking, lithium batteries are composed of several cells, and the liquid cooling pipes of each cell are connected in parallel. The above fire fighting methods are specifically divided into two types:

[0064] One is that when a battery cell has thermal runaway, the pressure inside the battery cell reaches the opening requirement of the explosion-proof valve, and the explosion-proof valve opens automatically. At this time, the pressure sensor installed on the water inlet pipe of the thermal runaway battery cell detects the pressure increase signal and feeds it back to the control device. The control device cuts off its water inlet pipe through the pressure sensors of other normally working batteries, and acts on the circulating pump to pressurize the coolant. The pressurized coolant quickly enters the explosion-proof valve of the thermal runaway battery cell, preventing the chemical reaction from proceeding and extinguishing the fire from the source.

[0065] The other is that the temperature sensor detects that a battery cell has thermal runaway, but the pressure inside the battery cell has not reached the requirement for opening the explosion-proof valve. At this time, the temperature sensor will feed back the thermal runaway signal to the control device. The control device cuts off the water inlet pipe through the pressure sensors of other normally working battery cells, and at the same time acts on the circulating pump to pressurize the coolant. The pressurized coolant quickly enters the thermal runaway battery cell and acts on the explosion-proof valve to open it. Then the coolant enters the thermal runaway battery cell through the explosion-proof valve position as a fire extinguishing agent to carry out fire fighting.

[0066] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. Those skilled in the art may change, modify, replace and deform the above embodiments within the scope of the present invention. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples without contradiction.

Claims

1. A lithium battery liquid cooling fire protection system, comprising a liquid cooling plate, a temperature sensor, a water inlet pipe (3), a water outlet pipe, a circulation pump, a coolant tank and a control device, wherein the liquid cooling plate comprises a liquid cooling plate body and two liquid cooling carriers (2), the liquid cooling plate body is located in each battery cell (1) and is provided with a liquid cooling flow channel, the two liquid cooling carriers (2) are respectively fixed on two cover plates (5) and are respectively used to connect the water inlet pipe (3) and the water outlet pipe, the coolant tank is connected to the water inlet pipe (3) through the circulation pump, the temperature sensor is arranged on the surface of the battery cell (1), an explosion-proof valve is arranged on a cover plate (5) of the battery cell (1), the control device is respectively electrically connected to the temperature sensor and the circulation pump, and is characterized in that: Two liquid cooling carriers (2) are fixedly connected to two cover plates (5) to form two cavities, the water inlet end of the liquid cooling channel and the explosion-proof valve are located in one of the cavities, and the water outlet end of the liquid cooling channel is located in the other of the cavities, a water nozzle assembly (213) is provided on the liquid cooling carrier (2), a pressure sensor (6) having the function of disconnecting the water inlet pipe (3) is provided on the water inlet pipe (3), and the pressure sensor (6) is electrically connected to the control device.

2. The lithium battery liquid cooling fire fighting system according to claim 1, characterized in that: The liquid cooling carrier comprises: an independently designed liquid cooling carrier cover plate (21) and a liquid cooling carrier body (22); the liquid cooling carrier body (22) is a fully enclosed structure with openings at both ends; the liquid cooling carrier cover plate (21) is fixedly connected to an open end of the liquid cooling carrier body (22); the other open end of the liquid cooling carrier body (22) is fixedly connected to the cover plate (5) after the water inlet end and the explosion-proof valve cover are arranged inside; and a water nozzle assembly (213) is arranged on the liquid cooling carrier cover plate (21).

3. The lithium battery liquid cooling fire fighting system according to claim 2, characterized in that: The liquid cooling carrier cover plate (21) comprises an integrally formed first cover plate (211) and a second cover plate (212); the first cover plate (211) is in a strip-shaped structure and its length matches the water inlet end; a first cavity (225) and a second cavity (226) are formed in the liquid cooling carrier body (22); the first cover plate (211) matches the top structure of the first cavity (225), and the second cover plate (212) matches the top structure of the second cavity (226).

4. The lithium battery liquid cooling fire fighting system according to claim 3, characterized in that: A through groove and an explosion-proof valve installation groove are arranged on the cover plate (5) adjacent to the water inlet end, the water inlet end is exposed through the through groove, a connecting portion (51) is fixed on the cover plate (5), the connecting portion (51) is partially hollowed out to form a third cavity (511) and a fourth cavity (512), the third cavity (511) is located at the outer periphery of the notch of the through groove, and the fourth cavity (512) is located at the outer periphery of the notch of the explosion-proof valve installation groove; a first boss (222) and a second boss (223) are arranged in sequence from top to bottom on the inner side surface of the liquid-cooling carrier body (22), the first boss (222) matches the structure of the liquid-cooling carrier cover plate (21), and the connecting portion (51) matches the structure of the second boss (223).

5. The lithium battery liquid cooling fire fighting system according to claim 4, characterized in that: The lower surface of the liquid cooling carrier cover plate (21) is fixedly connected to the upper surface of the first boss (222), and the inner side surface of the second boss (223) is fixedly connected to the outer side surface of the connecting portion (51).

6. The lithium battery liquid cooling fire fighting system according to claim 4, characterized in that: The connecting portion (51) and the cover plate (5) are integrally formed, and the first boss (222), the second boss (223) and the liquid cooling carrier body (22) are integrally formed.

7. The lithium battery liquid cooling fire fighting system according to claim 3, characterized in that: The faucet assembly (213) is arranged in the middle of the first cover plate (211).

8. The lithium battery liquid cooling fire fighting system according to claim 3, characterized in that: The corners of the long strip structure are transitioned by arcs, and the second cover plate (212) is a runway-shaped structure.

9. The lithium battery liquid cooling fire fighting system according to claim 8, characterized in that: The first cover plate (211) and the second cover plate (212) are in a T-shaped structure.

10. A lithium battery fire protection method, characterized in that: Using the lithium battery liquid cooling fire fighting system as described in any one of claims 1 to 9, when thermal runaway occurs, the control device acts on the pressure sensor to close the water inlet pipe of the normally working battery cell, and at the same time acts on the circulating pump to pressurize the coolant, and the coolant enters the thermal runaway battery cell through the explosion-proof valve position to play a fire fighting role.

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