Rapid automatic fire extinguishing system for liquid-cooled battery box based on thermal response fusing

Abstract

The invention discloses a liquid-cooled battery box rapid automatic fire extinguishing system based on thermal response fusing, which is composed of a liquid-cooled plate and an upper ladle cover, the liquid-cooled plate is provided with a cooling liquid interface, the liquid-cooled plate is paved with a continuous flow channel, a cooling liquid is connected into the flow channel through the interface, the liquid-cooled plate is provided with an integrated cooling unit, the cooling unit is provided with arrayed battery cavities, and the battery cavities are communicated with the upper ladle cover. A battery cell is arranged in the battery cavity, the battery cavity is aligned with the flow channel, and the cooling unit is communicated with the flow channel. By optimizing and improving the structure of the liquid cooling plate, the three-dimensional surrounding and cooling effects on the battery cell are better, the battery cavity is made of a material with a proper melting point, once battery cell level thermal runaway occurs, the battery cavity partition plate between the cooling liquid and the battery cell is melted at a high temperature, and the battery cell subjected to thermal runaway is rapidly immersed in the cooling liquid; and meanwhile, the control system timely introduces cooling liquid through an external cooling liquid pipeline for supplementing, the fire extinguishing effect is ensured, the whole process is automatically triggered, and external signals are not needed.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery thermal management, and more specifically, it relates to a rapid automatic fire extinguishing system for a liquid-cooled battery box based on thermally responsive fusing. Background Art

[0002] With the increasing demand for lithium-ion batteries in fields such as electric vehicles and energy storage, cooling the battery through liquid cooling technology has become an important means. Existing liquid-cooled batteries usually use metal materials such as aluminum foil membranes to form water channels for the coolant, that is, special liquid-cooled plates for batteries (specifically, refer to the patent content of "Liquid-Cooled Battery Box" with the application number CN201811250751.3), and are placed at the bottom of the liquid-cooled battery. The coolant only exchanges heat with the battery cells through heat transfer of the liquid-cooled plate and generally does not come into contact with the battery cells. In addition, the outer shell of the liquid-cooled battery generally has a high protection level, such as IP66 or higher, which can effectively prevent external liquids from entering the battery pack. However, when a liquid-cooled battery undergoes thermal runaway, especially when a very small number of lithium-ion battery cells in the battery pack undergo thermal runaway, due to the relatively tight protection of the outer shell, it is instead very difficult for the fire-fighting liquid medium to enter the runaway battery cells in time at the initial stage of thermal runaway for suppression. Traditional fire-fighting agents such as heptafluoropropane, perfluorohexanone, and aerosol can have an effect, but due to the self-sustained combustion characteristics of lithium battery fires, the fire extinguishing effect is often not good, the fire extinguishing process is slow, and it is easy to ignite the surrounding battery cells, causing the fire to spread. This has led to the industry problems of untimely fire extinguishing and unreliable fire extinguishing in current liquid-cooled battery packs.

[0003] The limitation of the existing liquid-cooled battery structure is that the coolant is only used to cool the battery cells and cannot effectively intervene in the thermally runaway battery cells. Especially when thermal runaway occurs suddenly and the external fire-fighting liquid medium cannot effectively contact the target battery cells in the first time, it will delay the fire extinguishing opportunity and spread the fire. Therefore, there is an urgent need for a mechanism to trigger fire extinguishing measures based on the self-sustained combustion characteristics of the material itself to solve the industry pain points. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a rapid automatic fire extinguishing system for a liquid-cooled battery box based on thermally responsive fusing to solve one or more of the above problems.

[0005] To achieve the above purpose, the present invention provides the following technical solutions: A rapid automatic fire extinguishing system for a liquid-cooled battery box based on thermally responsive fusing, which is composed of a liquid-cooled plate and an upper cover. The liquid-cooled plate is provided with a coolant interface, and a continuous flow channel is laid on the liquid-cooled plate. The coolant is connected into the flow channel through the interface. The liquid-cooled plate is provided with an integrated cooling unit. The cooling unit is provided with an array of battery cavities. Battery cells are arranged in the battery cavities. The battery cavities are arranged in alignment with the flow channel. The cooling unit is communicated with the flow channel.

[0006] Further, the cooling unit is a hollow internal surrounding diversion structure, and the surrounding diversion structure is communicated with the flow channel.

[0007] Further, the battery cavity is made of a material with a melting point lower than the thermal runaway extreme temperature of the battery cell.

[0008] Further, when the battery cell undergoes thermal runaway, the battery cavity near the target battery cell heats up and melts, and the coolant is injected into the battery cavity where the target battery cell is located.

[0009] Further, the coolant interface is connected to an external coolant pipeline, and the control system of the battery box controls the flow rate of the coolant.

[0010] Further, the control system of the battery box monitors each battery cell through one or more of a temperature sensor, a smoke sensor, and a flame sensor for each battery cavity.

[0011] Further, when the battery cell undergoes thermal runaway, the sensor triggers the control system to adjust the coolant pipeline to supplement the coolant to the flow channel.

[0012] Further, the coolant is continuously injected into the battery cavity in a submerged manner.

[0013] In summary, the present invention has the following beneficial effects: 1. By optimizing and improving the structure of the liquid cooling plate, with the design of the bottom plate cooperating with the grooved pedestal, the coolant route is designed into a three-dimensional surrounding area including the bottom, side, and top, with a closer fit, a larger cooling effect area, and better cooling effect; 2. The coolant forms a direct contact channel, and the battery cavity is made of a material with a suitable melting point. Once the battery cell undergoes thermal runaway, the cavity surrounding diversion structure is melted by high temperature, and the coolant can quickly submerge the target area, achieving a self-triggered thermal response fusing mechanism and reducing the risk of fire spread; 3. The control system of the battery box adds a battery cavity monitoring function, and replenishes the coolant in time after thermal runaway to ensure that the battery cell undergoing thermal runaway is completely submerged. Description of the Drawings

[0014] Figure 1 is a partial cross-sectional view of an embodiment provided by the present invention; Figure 2 is a trigger schematic diagram of an embodiment provided by the present invention; Figure 3 is a principle flow chart of an embodiment provided by the present invention.

[0015] In the figure: 1. Liquid cooling plate; 2. Upper cover; 3. Coolant interface; 4. Flow channel; 5. Cooling unit; 6. Battery cavity; 7. Battery cell; 8. Surrounding diversion structure. Detailed Embodiment

[0016] Embodiment: The following will further elaborate on the present invention in conjunction with the attached Figures 1-3 drawings.

[0017] A rapid automatic fire extinguishing system for a liquid-cooled battery box based on thermally responsive fusing, as Figure 1 shown in Figure 2 , includes a liquid-cooling plate 1, an upper cover 2, a flow channel 4, a cooling unit 5, and a coolant interface 3. The liquid-cooling plate 1 is a flat rectangular sheet metal part. The liquid-cooling plate 1 is installed with a matching upper cover 2 to cover the main functional area of the liquid-cooling plate 1, forming a closed structure. A continuous flow channel 4 is laid on the surface of the liquid-cooling plate 1, that is, a meandering continuous flow channel 4 is laid on the surface of the liquid-cooling plate 1. The liquid-cooling plate 1 is provided with two coolant interfaces 3 corresponding to the inlet and outlet. The coolant interfaces 3 are connected to an external coolant pipeline. The external coolant pipeline normally participates in the coolant circulation to cool the battery cells 7. Once a thermal runaway of the battery cells 7 occurs, it quickly switches to supplementing the coolant to the battery cavity to complete immersion. The control system includes, but is not limited to, a monitoring module, a processing and computing module, an alarm module, etc. The monitoring module includes one or more of a temperature sensor, a smoke sensor, and a flame sensor. Sensors are provided in each battery cavity 6, and the types of sensors are not limited to this. The purpose is to be able to monitor changes in the thermal runaway and self-ignition of the battery cells 7, such as an increase in temperature, the generation of smoke, the generation of flames, etc. The control system can monitor each battery cell 7 individually. The liquid-cooling plate 1 is provided with an integrally formed cooling unit 5. The cooling unit 5 is provided with a plurality of battery cavities 6 in an array. The cooling unit 5 as a whole is an internally hollow surrounding flow guiding structure 8, that is, the part of the cooling unit 5 corresponding to each adjacent battery cavity 6 is internally hollow, leaving a space for the coolant to circulate. The cooling unit 5 is connected to the flow channel 4 through the surrounding flow guiding structure 8, that is, the flow channel 4 is connected to the surrounding flow guiding structure 8. In this way, the coolant forms a circulation line from the flow channel 4 to the surrounding flow guiding structure 8, and the external coolant pipeline controllably intervenes in this line. The battery cavity 6 can be a porous ceramic structure or other structures. When a thermal runaway occurs in one battery cavity 6, the coolant will spread and immerse all other battery cavities 6 in a point-to-surface manner, that is, once a thermal runaway occurs, for safety reasons, all the battery cells in the entire battery box are immersed in the coolant to avoid greater losses. The battery cavity 6 is arranged aligned with the flow channel 4. The battery cavity 6 is provided with a battery cell 7. The contact surface between the battery cavity 6 and the battery cell 7 is directly replaced by the surface of the flow channel 4, that is, the flow channel 4 can directly contact the battery cell 7 in the battery cavity 6 to complete heat exchange. The main part of the battery cavity 6 corresponding to the plate in contact with the cooling unit 5 and the battery cell 7 is made of a material with a temperature lower than the thermal runaway extreme temperature of the battery cell 7, which can be replaced according to different situations such as the type and size of the battery cell 7.

[0018] When the battery cell 7 is operating normally, the coolant circulates within the flow channels 4 and the surrounding flow guiding structure 8, and cools down the battery cell 7 through heat exchange. Therefore, it is required that the coolant can be selected according to actual application requirements, and must have high thermal conductivity to transfer the heat released by the battery cell 7 in a short time. The coolant also needs to have good chemical stability and electrical insulation properties to promptly extinguish the fire caused by the thermal runaway of the battery cell 7 and prevent secondary damage to the battery box. The external coolant pipeline manually or periodically replenishes the normal loss of the coolant, and if necessary, the coolant used for a long time can be emptied and replaced regularly. When the battery cell 7 experiences thermal runaway, the battery cavity 6 near the target battery cell 7 rapidly heats up. The temperature of the thermal runaway of the battery cell 7 is generally higher than the melting point of the material of the battery cavity 6. Therefore, the battery cavity 6 meets the melting condition, and the battery cavity 6 begins to melt. The coolant is passively injected into the battery cavity 6 where the target battery cell 7 is located in a submerged manner, submerging the thermally runaway battery cell 7. To prevent the coolant from being insufficient to completely submerge the thermally runaway battery cell 7, the control system monitors the occurrence of thermal runaway through sensors and responsively introduces sufficient coolant from the external coolant pipeline for replenishment, actively injecting it into the battery cavity 6 where the target battery cell 7 is located until the battery cell 7 in the battery cavity 6 is completely submerged. In addition to having the basic heat transfer function, the coolant also has a fire extinguishing function. It can evenly submerge and cover the fire area when the battery cell 7 experiences thermal runaway, quickly self-respond, and does not require external instructions. In the case where the protection level of the battery box shell is relatively high and it is difficult to import the fire extinguishing liquid medium from the outside in a timely manner, it can effectively control and extinguish the fire with little harm to the surrounding environment. The material used for the battery cavity 6 should match the thermal runaway threshold of the battery cell 7, have high thermal conductivity, high chemical stability, a failure probability < 0.1%, a high safety factor, and effectively prevent incorrect fuse triggering. The entire trigger is based on an automated control system, completely self-responding, and more timely. The application scenario of the entire set of designs is extensive and is suitable for scenarios of high-energy-density batteries such as electric vehicles and energy storage systems.

[0019] It should be noted that this specific embodiment is only an explanation of the present invention and does not limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions according to needs, but as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A liquid-cooled battery box rapid automatic fire extinguishing system based on thermal response fusing, which consists of a liquid cooling plate and an upper cover, the liquid cooling plate is provided with a coolant interface, the liquid cooling plate is paved with a continuous flow channel, and the coolant is connected to the flow channel through the interface, and is characterized in that: The liquid cooling plate is provided with an integrated cooling unit. The cooling unit is provided with an array of battery cavities. The battery cavities are provided with battery cells. The battery cavities are aligned with the flow channels, and the cooling unit is communicated with the flow channels.

2. According to claim 1, the liquid-cooled battery box rapid automatic fire extinguishing system based on thermal response fusing is characterized in that: The cooling unit is a surrounding flow guiding structure with a hollow interior, and the surrounding flow guiding structure is communicated with the flow channel.

3. The liquid-cooled battery box rapid automatic fire extinguishing system based on thermal response fusing according to claim 1 is characterized in that: The battery cavity is made of a material with a melting point lower than the thermal runaway extreme temperature of the battery cell.

4. The liquid-cooled battery box rapid automatic fire extinguishing system based on thermal response fusing according to claim 3 is characterized in that: When a battery cell experiences thermal runaway, the battery cavity near the target battery cell heats up and melts, and coolant is injected into the battery cavity where the target battery cell is located.

5. The liquid-cooled battery box rapid automatic fire extinguishing system based on thermal response fusing according to claim 1 is characterized in that: The coolant interface is connected to the external coolant pipeline, and the management and control system of the battery box controls the flow of the coolant.

6. The liquid-cooled battery box rapid automatic fire extinguishing system based on thermal response fusing according to claim 5 is characterized in that: The management and control system of the battery box monitors each battery cell in each battery cavity through one or more sensors including temperature sensors, smoke sensors and flame sensors.

7. The liquid-cooled battery box rapid automatic fire extinguishing system based on thermal response fusing according to claim 6 is characterized in that: Thermal runaway of the battery cell triggers the control system through sensors to adjust the coolant pipeline to add coolant to the flow channel.

8. The liquid-cooled battery box rapid automatic fire extinguishing system based on thermal response fusing according to claim 7 is characterized in that: The coolant is continuously injected into the battery cavity in an immersion manner.

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