Direct cooling system with fire extinguishing function and battery pack

Abstract

This invention discloses a direct cooling system and battery pack with fire extinguishing function, relating to the field of new energy battery technology. The direct cooling system with fire extinguishing function includes a compressor, condenser, expansion valve, and evaporator connected in series in a closed loop. Several branch channels are connected in parallel between the condenser and the expansion valve, and several fire extinguishing assemblies are connected between adjacent branch channels. Each fire extinguishing assembly includes a fire detection tube that laterally crosses the battery cell. This direct cooling system and battery pack with fire extinguishing function can effectively solve the dual problems of low heat dissipation efficiency and delayed fire extinguishing response in the prevention and control of thermal runaway in power batteries.

Description

Technical Field

[0001] This invention relates to the field of new energy battery technology, and more specifically, to a direct cooling system and battery pack that also has fire extinguishing function. Background Technology

[0002] Power batteries are highly susceptible to thermal runaway under abusive conditions such as overcharging, short circuits, or mechanical damage, which can lead to fires or even explosions. Thermal runaway is essentially a vicious cycle of "exothermic - heating - accelerated reaction". Once triggered, the internal temperature of the battery can soar to hundreds of degrees Celsius in a very short time, accompanied by electrolyte decomposition, flammable gas injection, and the release of toxic substances (such as HF), posing a serious threat to life and property safety.

[0003] To address the aforementioned risks, existing technologies primarily rely on independent thermal management and fire suppression systems. Regarding thermal management, while mainstream liquid cooling technology can effectively remove heat generated by the battery, its cooling efficiency is limited by the latent heat of phase change of the coolant, and the system structure is complex and prone to leakage. Air cooling, on the other hand, suffers from low air heat transfer coefficients, making it difficult to meet the heat dissipation requirements of high-rate charging and discharging scenarios. Although direct cooling technology utilizes the refrigerant's direct phase change in the evaporator to absorb heat, possessing a much higher heat transfer efficiency than liquid cooling, existing direct cooling systems mostly focus on conventional heat dissipation functions and lack emergency response mechanisms for sudden thermal runaway events.

[0004] In the field of fire protection, traditional fire extinguishing methods have significant limitations: dry powder fire extinguishers can only extinguish external flames and cannot penetrate the battery module for deep cooling; water-based fire extinguishing systems have a certain cooling effect, but the high conductivity of water may cause battery short circuits, and the reaction with the internal materials of the battery may generate more toxic gases (such as CO and HF); inert gas fire extinguishing agents are difficult to suppress the continuous combustion caused by the decomposition of the positive electrode material and the release of oxygen during thermal runaway; in addition, most existing fire-fighting devices are independent additional components, which not only occupy extra space, but also have no synergistic effect with the battery thermal management system, making it difficult to achieve rapid and accurate suppression in the early stages of thermal runaway.

[0005] In summary, how to solve the dual challenges of low heat dissipation efficiency and delayed fire extinguishing response in the prevention and control of thermal runaway in power batteries is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a direct cooling system and battery pack that also has fire extinguishing function, which can effectively solve the dual problems of low heat dissipation efficiency and delayed fire extinguishing response in the prevention and control of thermal runaway of power batteries.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A direct cooling system that also functions as a fire extinguishing system is used for heat dissipation of battery cells; The direct cooling system, which also has fire extinguishing function, includes a compressor, condenser, expansion valve and evaporator connected in series in a closed loop. Several branch channels are connected in parallel between the condenser and the expansion valve, and several fire extinguishing assemblies are connected between two adjacent branch channels. The fire extinguishing assembly includes a fire detection tube that is used to laterally cross the battery cell.

[0008] In some technical solutions, a pressure reduction component is provided at the upstream end of each branch channel.

[0009] In some technical solutions, the fire extinguishing assemblies in different branch channel intervals are arranged alternately and staggered.

[0010] In some technical solutions, the evaporator includes several heat exchange plates, which are arranged alternately with the battery cell and in contact with it for heat exchange; The heat exchange plate includes an upward channel, a downward channel, and several heat exchange channels; The upward channel is connected to the condenser or the expansion valve; The downlink channel is connected to the compressor; The heat exchange channel connects the upward channel and the downward channel.

[0011] In some technical solutions, the evaporator further includes a liquid inlet pipe and a gas return pipe; The upward channel is connected to the liquid inlet pipe, and a pressure reducing component is provided at the connection point; The downflow channel is connected to the return air pipe.

[0012] In some technical solutions, the heat exchange plate is provided with several plug-in sockets for detachable plug-in connection to the fire detection tube.

[0013] In some technical solutions, the connector includes a snap-fit ​​groove and a plug-in protrusion, wherein the plug-in protrusion is provided with a plug-in channel communicating with the uplink channel; The fire extinguishing assembly also includes a connecting component, which is disposed at the end of the fire detection tube. The connecting component includes a limiting protrusion and a plug hole communicating with the fire detection tube. The limiting protrusion engages with the locking groove, and the insertion protrusion is in the insertion hole, for making the insertion channel and the insertion hole connected.

[0014] In some technical solutions, the fire extinguishing assembly also includes a shield, which is used to cover the fire detection tube so that the internal medium can be sprayed in a preset direction after the fire detection tube is broken.

[0015] A battery pack comprising a plurality of battery cells and a direct cooling system with fire extinguishing function as described in any of the above embodiments.

[0016] The direct cooling system with fire extinguishing function provided by this invention has at least the following advantages compared with the prior art: 1. By combining the direct cooling system and the fire extinguishing system into one, it achieves both cell heat dissipation under normal operating conditions and fire extinguishing under thermal runaway conditions. There is no need to add separate fire extinguishing pipelines or liquid storage tanks, which reduces the redundant structure inside the battery pack and improves the space utilization and energy density of the battery pack.

[0017] 2. The fire detection tube, which is horizontally installed across the battery cell, can quickly detect abnormal high temperatures or flames in the battery cell. When the battery cell experiences thermal runaway, the high temperature will directly soften or melt the fire detection tube, allowing the internal refrigerant to quickly act on the battery cell to extinguish the fire. It can automatically trigger the fire extinguishing assembly to open without the need for an external power source or complex electronic control signals. The branch channel is directly connected to the fire extinguishing assembly. The refrigerant, with its own suffocating, heat-absorbing, or chemically inhibiting effects, can be directly sprayed onto the surface of the burning battery cell, rapidly reducing the temperature and isolating oxygen, effectively cutting off the chain reaction of thermal runaway.

[0018] 3. Several branch channels are set between the condenser and the expansion valve so that when a local thermal runaway occurs in a certain cell and the fire suppression is initiated, the refrigeration cycle of the entire system will not be completely cut off, or the normal heat dissipation of other areas can be guaranteed by design, thereby improving the fault tolerance and safety of the system.

[0019] The battery pack provided by this invention includes the aforementioned direct cooling system that also has fire extinguishing function, and has the same beneficial effects. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of the heat exchange plate provided by the present invention; Figure 2 for Figure 1 Enlarged view of point A in the middle; Figure 3 for Figure 1 Enlarged view of point B in the middle; Figure 4 A longitudinal sectional view of the heat exchange plate provided by the present invention; Figure 5 This is a longitudinal sectional view of another embodiment of the heat exchange plate provided by the present invention; Figure 6This is an assembly diagram of the heat exchange plate and fire extinguishing assembly provided by the present invention; Figure 7 for Figure 6 Enlarged view of point C in the middle; Figure 8 This is a top view of the heat exchange plate and fire extinguishing assembly provided by the present invention after assembly. Figure 9 This is a schematic diagram of the fire extinguishing assembly provided by the present invention; Figure 10 This is a structural schematic diagram of the fire extinguishing assembly provided by the present invention from another perspective; Figure 11 This is a cross-sectional view of the fire extinguishing assembly provided by the present invention.

[0022] In the picture: 1. Heat exchange plate; 11. Single plate; 111. Flow equalization channel; 1111. Jet channel; 1112. Protrusion; 1113. Corrugated inner wall; 112. Heat exchange channel; 1121. Arc wall; 113. Partition plate; 1131. Limiting groove; 1132. Limiting tooth; 12. Side baffle; 13. Top baffle; 131. Upward channel; 1311. Expansion assembly; 1312. Insertion protrusion; 132. Snap-fit ​​groove; 14. Bottom baffle; 141. Downward channel; 15. Strain gauge; 2. Fire extinguishing assembly; 21. Connecting component; 211. Connecting passage; 212. Limiting protrusion; 213. Insertion hole; 214. Rotating shaft; 215. Fixing fin; 22. Fire detection tube; 23. Cover; 231. Receiving area; 232. Shielding cover; 233. Buckle; 234. Hinge; 2341. Hinge hole; 3. Liquid inlet pipe; 4. Gas return pipe. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] The core of this invention is to provide a direct cooling system and battery pack that also has fire extinguishing function, which can effectively solve the dual problems of low heat dissipation efficiency and delayed fire extinguishing response in the prevention and control of thermal runaway of power batteries.

[0025] In the existing technology, the heat dissipation and fire protection systems of power batteries are two independent systems, which occupy a large space and have problems such as low heat dissipation efficiency and delayed fire extinguishing response when the battery is thermally runaway. Example 1

[0026] In view of the above problems, this application provides a direct cooling system with fire extinguishing function for heat dissipation of battery cells; A direct cooling system with fire extinguishing function includes a compressor, condenser, expansion valve and evaporator connected in series in a closed loop; Several branch channels are connected in parallel between the condenser and the expansion valve, and several fire extinguishing assemblies 2 are connected between two adjacent branch channels; The fire extinguishing assembly 2 includes a fire detection tube 22, which is used to traverse the battery cell laterally.

[0027] like Figure 7 and Figure 8 As shown, a mechanical refrigeration cycle consisting of a compressor, condenser, expansion valve and evaporator is used to achieve direct cooling of the battery pack, which effectively improves the heat dissipation efficiency of the battery pack. Meanwhile, the circulating medium in the mechanical cooling system is a refrigerant, which typically has suffocating, heat-absorbing, and chemically inhibiting effects, such as heptafluoropropane, perfluorohexanone, and trifluoroiodomethane. When the cell experiences thermal runaway and the temperature exceeds the rupture temperature of the fire detection tube 22, the fire detection tube 22 can rupture rapidly, allowing the low-temperature refrigerant to directly act on the overheated hot spot. This achieves the functions of rapidly isolating the overheated hot spot from air, cooling it, and extinguishing the fire. In other words, the fire protection system and the heat dissipation system are integrated into one unit, eliminating the need for a dedicated liquid storage tank to store the fire extinguishing agent. This improves the space utilization rate within the battery pack. Furthermore, the design of the fire detection tube 22 significantly enhances the response rate and enables the refrigerant to accurately act on the overheated hot spot, thereby quickly resolving the overheating or fire problem of the cell and significantly improving the safety performance of the battery pack.

[0028] Moreover, the network design of multi-branch channels and fire detection tubes 22 enables simultaneous fire suppression when multiple points of the battery cell overheat. This avoids the problem of multiple points of overheating being unable to be solved because the refrigerant cannot flow after a single fire detection tube 22 partially breaks.

[0029] Several branch channels are set up in parallel between the condenser and the expansion valve, and the fire extinguishing assembly 2 or the fire detection tube 22 is set between the branch channels. When a single fire extinguishing assembly 2 or the fire detection tube 22 breaks, it is used for fire extinguishing and will not completely cut off the refrigeration cycle of the entire system. Or it can ensure the normal heat dissipation of other areas through design, thereby improving the fault tolerance and safety of the system.

[0030] Moreover, compared to conductive water-based fire extinguishing agents, the refrigerant used in mechanical refrigeration cycle systems has good electrical insulation properties, and will not cause secondary disasters such as short circuits or electric shocks when sprayed onto charged battery modules.

[0031] In some embodiments, a pressure reduction component is provided at the upstream end of each branch channel.

[0032] By setting a pressure reducing component at the upstream end of the branch channel, the high-pressure liquid refrigerant is converted into a low-pressure gas-liquid two-phase flow. When the fire detection tube 22 is heated and ruptures, the medium can be more quickly and completely vaporized, absorbing a large amount of latent heat to rapidly reduce the temperature of the battery cell. At the same time, pre-decompression can prevent the high-pressure liquid column from directly impacting the fire detection tube 22 and causing accidental rupture, which improves the stability of the system during normal operation. This ensures that the fire detection tube 22 can only be broken by internal pressure when its strength decreases due to high temperature softening, thus enhancing the reliability of the operation. Meanwhile, a pressure reducing component is installed at the upstream end of each branch channel, which helps to even out the flow of refrigerant between the various branch channels. Furthermore, even if the flame probe 22 in the corresponding branch channel breaks, there will still be some flow resistance in that branch channel, thus ensuring the normal flow of refrigerant in the remaining branch channels and preventing all the cells from losing their heat dissipation capacity.

[0033] In some embodiments, the fire extinguishing assemblies 2 in different branch passage intervals are arranged alternately and staggered.

[0034] By arranging the fire extinguishing assemblies 2 alternately and staggeredly in different branch channel intervals, it helps to increase the coverage of the fire detection tube 22 on the battery cell, reduce monitoring and fire-fighting blind spots, and avoid the connection ports of multiple fire detection tubes 22 being concentrated at one point.

[0035] In some embodiments, the evaporator includes a plurality of heat exchange plates 1, which are arranged alternately with the battery cells and abut against each other for heat exchange; The heat exchange plate 1 includes an upward channel 131, a downward channel 141, and several heat exchange channels 112; The upward channel 131 connects to the condenser or expansion valve; Downlink channel 141 connects to the compressor; The heat exchange channel 112 connects the upward channel 131 and the downward channel 141.

[0036] The plate heat exchanger is used to directly contact the side wall of the battery cell for heat exchange. The design of the upward channel 131 and the downward channel 141 makes the refrigerant more evenly distributed in the heat exchange plate 1, reduces the flow dead zone, and ensures that the heat generated by the battery cell can be quickly discharged.

[0037] In some cases, the upward channel 131 is connected to the expansion valve, meaning that the refrigerant expands through the expansion valve before entering the evaporator for heat exchange; In some cases, the upward channel 131 is connected to the condenser, meaning that the low-temperature refrigerant directly enters the upward channel 131. An expansion component 1311 is installed at the connection between the upward channel 131 and the heat exchange channel 112, so that the refrigerant expands and vaporizes at the expansion component 1311 before entering the heat exchange channel 112. By installing an expansion component 1311 at the upstream end of each heat exchange channel 112, the heat exchange channel 112 has controllable flow resistance, which promotes the uniform flow of refrigerant in different heat exchange channels 112 and improves the temperature uniformity performance of the battery cell.

[0038] In some embodiments, the evaporator further includes a liquid inlet pipe 3 and a gas return pipe 4; The upward channel 131 is connected to the inlet pipe 3, and a pressure reducing component is provided at the connection point; Downstream channel 141 is connected to return air pipe 4.

[0039] By placing the pressure reducing component at the connection between the liquid inlet pipe 3 and the upward channel 131, precise control of the refrigerant flow and pressure entering the evaporator is achieved, ensuring that the amount of refrigerant obtained by each heat exchange plate 1 is similar, which helps to improve the temperature consistency of the cells in the battery pack and avoid local overheating that could lead to thermal runaway. Meanwhile, the pressure reduction component enables each upward channel 131 to obtain controllable flow resistance. When a single heat exchange plate 1 is damaged, the remaining heat exchange plates 1 can still obtain sufficient refrigerant pressure, thereby ensuring the heat dissipation capacity of the corresponding battery cell.

[0040] In some embodiments, the heat exchange plate 1 is provided with a plurality of plug-in sockets for detachably plugging in the fire probe 22.

[0041] The upward channel 131 of the heat exchange plate 1 is used as a branch channel for the flow of refrigerant. The fire detection tube 22 directly obtains refrigerant from the upward channel 131. Under normal heat dissipation conditions, the pressure at both ends of the fire detection tube 22 is equal, that is, there is no refrigerant flow inside. When the fire detection tube 22 ruptures, both ends of the fire detection tube 22 can simultaneously obtain refrigerant from the corresponding upward channel 131, thereby enabling a large amount of refrigerant to act quickly on the hot spot, effectively improving the fire response speed and fire extinguishing capability.

[0042] Moreover, the structure design of the heat exchange plate 1 integrated plug-in base is adopted. By fixing the heat exchange plate 1 and the battery cell, the position of the flame probe 22 is fixed, avoiding the vibration of the flame probe 22 during vehicle operation. At the same time, the detachable design allows a single flame probe 22 to be replaced individually after damage, reducing maintenance costs.

[0043] In some embodiments, the connector includes a snap-fit ​​groove 132 and a plug-in protrusion 1312, the plug-in protrusion 1312 being provided with a plug-in channel communicating with the uplink channel 131; The fire extinguishing assembly 2 also includes a connecting component 21, which is disposed at the end of the fire detection tube 22. The connecting component 21 includes a limiting protrusion 212 and a plug hole 213 communicating with the fire detection tube 22. The limiting protrusion 212 is engaged with the locking groove 132, and the insertion protrusion 1312 is inserted into the insertion hole 213 to make the insertion channel and the insertion hole 213 connected.

[0044] like Figures 7-9 As shown, a connection channel 211 is provided in the connection component 21 for connecting the insertion hole 213 and the fire detection tube 22; When the connecting component 21 is assembled with the plug socket, mechanical locking is achieved through the cooperation of the snap-fit ​​groove 132 and the limiting protrusion 212, and flow path is achieved through the cooperation of the plug protrusion 1312 and the plug hole 213. Through the structural design of the plug-in socket and connecting component 21, the simultaneous operation of mechanical fixation and flow path connection is realized; while the fire probe tube 22 is installed and fixed, its internal flow channel is automatically connected to the upward channel 131 in the heat exchange plate 1, and it can withstand the impact of high-pressure refrigerant. In the event that the fire detection tube 22 breaks due to fire melting, the connecting assembly 21 can prevent the tube from splashing, thus improving safety in emergency situations.

[0045] In some embodiments, the fire extinguishing assembly 2 further includes a shield 23 for covering the fire detection tube 22 so that the internal medium of the fire detection tube 22 can be sprayed in a preset direction after the fire detection tube 22 is broken.

[0046] like Figure 11 As shown, by adding a shield 23, the refrigerant after the rupture is forced to concentrate and spray towards the battery cell, rather than spreading randomly in all directions. This ensures that the refrigerant can accurately cover the heat source, quickly reduce the battery cell temperature, and dilute or isolate the oxygen concentration.

[0047] In addition, the shield 23 can also protect the fire detection tube 22 from accidental damage caused by external mechanical scratches to a certain extent, and improve the system's anti-interference ability under complex working conditions. Example 2

[0048] This application also provides a heat exchange plate for a direct cooling system for battery cells, used for heat dissipation of battery cells; A heat exchange plate for a direct cooling system for battery cells, comprising several sets of parallel heat exchange units; The heat exchange unit includes a flow equalization channel 111 and a heat exchange channel 112. The outer sidewalls of the flow equalization channel 111 and the heat exchange channel 112 are used to contact the battery cell for heat exchange. The common sidewall of the flow equalization channel 111 and the heat exchange channel 112 is provided with several interconnected jet channels 1111. The flow equalization channel 111 and heat exchange channel 112 of two adjacent heat exchange units are arranged in opposite positions.

[0049] like Figure 1 As shown, the dual-channel design of the flow equalization channel 111 and the heat exchange channel 112 ensures that the refrigerant flows evenly within the flow equalization channel 111, improving temperature uniformity. The refrigerant also impacts the inner wall of the heat exchange channel 112 in the form of a jet through the jet channel 1111, which helps to break the boundary layer of the fluid within the heat exchange channel 112, increasing the local Nusselt number and improving heat exchange efficiency. Moreover, during the temperature uniformity stage, when the refrigerant is within the flow equalization channel 111, it can also contact the battery cell for heat exchange through the inner wall of the flow equalization channel 111.

[0050] Moreover, when direct cooling is used, the refrigerant introduced into the flow equalization channel 111 is in liquid or gas-liquid mixture state. When the refrigerant comes into contact with the battery cell through the inner wall of the flow equalization channel 111 and exchanges heat, it can further improve the gas-liquid conversion rate of the refrigerant in the flow equalization channel 111, increase the refrigerant pressure in the flow equalization channel 111, and thus increase the jet velocity in the jet channel 1111. This helps to further reduce the boundary layer effect in the heat exchange channel 112, thereby improving the heat exchange efficiency and meeting the heat dissipation requirements of the battery cell for instantaneous high heat energy. Meanwhile, the design of the flow equalization channel 111 and the heat exchange channel 112 has an internal cross-sectional diameter larger than that of the microchannel. When the heat exchange plate 1 is squeezed, it is not easy to get blocked, thus avoiding loss of heat exchange performance.

[0051] The flow equalization channel 111 and heat exchange channel 112 of two adjacent heat exchange units are arranged in opposite positions, that is, flow equalization channel 111 and heat exchange channel 112 are provided on both sides of heat exchange plate 1, which helps to improve the temperature equalization performance of the battery cells on both sides of heat exchange plate 1. Through the series and parallel design of multiple heat exchange plates 1, the temperature equalization performance of the entire battery pack is guaranteed.

[0052] In some cases, the diameter of the jet channel 1111 is small. When the refrigerant is jetted through the jet channel 1111, it can be throttled twice to increase the gas-liquid conversion rate and reduce the temperature of the refrigerant itself. This increases the temperature difference between the inner and outer walls of the heat exchange channel 112 and improves the heat exchange efficiency.

[0053] In some embodiments, the common sidewall is an arc-shaped structure that bends toward the heat exchange channel 112, and a protrusion 1112 is provided toward the inner sidewall of the heat exchange channel 112, and a jet channel 1111 is provided on the protrusion 1112.

[0054] The shared sidewall design with an arc structure effectively improves the rigidity of the heat exchange plate 1 and reduces its deformation probability. At the same time, the arc structure bends toward the heat exchange channel 112, which can concentrate the refrigerant and help improve the jet velocity. By setting the protrusion 1112 and placing the jet channel 1111 on the protrusion 1112, the outlet of the jet channel 1111 can be close to the inner wall of the heat exchange channel 112, reducing the influence of the fluid in the heat exchange channel 112 on the flow direction of the jet, further increasing the local Nusselt number, and improving the heat exchange efficiency.

[0055] In some embodiments, the inner wall of the heat exchange channel 112 is an arc-shaped wall 1121 with a central depression.

[0056] Compared to a flat inner wall, the curved wall 1121 effectively increases the heat exchange surface area, which helps to improve heat exchange efficiency. Meanwhile, the concave arc-shaped wall 1121 can guide the fluid to diffuse to both sides instead of splashing when receiving the jet, effectively reducing the heat exchange dead angle at the edge of the heat exchange channel 112, improving the temperature uniformity performance, and reducing the kinetic energy loss caused by fluid separation and impact at the bend, that is, effectively reducing the fluid flow resistance and reducing the overall power consumption of the direct cooling system.

[0057] In some embodiments, a top stop 13 and a bottom stop 14 are also included; The top baffle 13 is provided with an upward channel 131, which is connected to the flow equalization channel 111; The bottom baffle 14 is provided with a downward channel 141, which is connected to the heat exchange channel 112.

[0058] like Figure 4 and Figure 5 As shown, the top baffle 13 and bottom baffle 14 integrate an upward channel 131 and a downward channel 141, which realizes the distribution of refrigerant in different heat exchange units. This achieves vertical manifolds for different heat exchange units, shortens the flow distance of each heat exchange unit, effectively reduces flow resistance, and helps to reduce the power of the circulating pump, thereby improving the energy efficiency ratio of the whole vehicle or system.

[0059] Moreover, the design of the internal integrated channels of the top baffle 13 and the bottom baffle 14 avoids complex pipe layout and effectively saves space in the battery pack. At the same time, the top baffle 13 and the bottom baffle 14 can achieve the sealing of the heat exchange unit through specific assembly structures, such as sealing strips between the top baffle 13, the bottom baffle 14 and the heat exchange plate 1, or by integral brazing or laser welding to improve the sealing performance.

[0060] In some cases, the top baffle 13 and the bottom baffle 14 are respectively installed on the upper and lower sides of the heat exchange plate 1, while the left and right sides are respectively equipped with side baffles 12 for sealing.

[0061] In some embodiments, an expansion component 1311 is provided at the connection position between the uplink channel 131 and the flow equalization channel 111.

[0062] like Figure 5As shown, in some cases, the expansion component 1311 is a slender channel, that is, a controllable flow resistance is added at the connection position between the flow equalization channel 111 and the upward channel 131, thereby eliminating the near-end effect of the upward channel 131 and realizing flow equalization among all flow equalization channels 111. Moreover, the liquid refrigerant in the upward channel 131 can increase the gas-liquid conversion rate, reduce the refrigerant temperature, increase the temperature difference inside and outside the heat exchange plate 1, and improve the heat exchange efficiency when passing through the expansion component 1311.

[0063] In some embodiments, the heat exchange plate for the direct cooling system of the battery cell further includes two symmetrically arranged single plates 11; Several sets of flow equalization channels 111 are arranged in parallel and at intervals on the single plate 11; The flow equalization channels 111 of the two single boards 11 are arranged alternately; The flow equalization channel 111 of one single plate 11 and the flow equalization channel 111 of another single plate 11 form a heat exchange unit.

[0064] The heat exchange plate 1 adopts two single plates 11 symmetrically arranged, and forms a heat exchange unit by combining different channels at corresponding positions. Through the modular design, the processing difficulty of the heat exchange plate 1 is effectively reduced, thereby reducing the cost of use.

[0065] Furthermore, flow equalization channels 111 are arranged at intervals within the single plate 11, and the intervals of the flow equalization channels 111 are used to form a heat exchange channel 112 with another single plate 11. That is, the flow equalization channels 111 and heat exchange channels 112 of different heat exchange units within the single plate 11 are arranged alternately. Although the heat dissipation efficiencies of the two are different, the single plate 11 itself has a certain heat transport capacity, so that heat can move laterally along the single plate 11, achieving temperature equalization in different areas of the single plate 11 contact position.

[0066] In some embodiments, partition plates 113 are provided on both sides of the flow equalization channel 111, and the partition plates 113 are arranged in a cantilever form perpendicular to the single plate 11. The partition plates 113 at corresponding positions of the two single plates 11 abut and seal to form a heat exchange channel 112.

[0067] The partition plate 113 adopts a cantilever design, which can be integrally formed with the single plate 11 to avoid secondary assembly. Furthermore, the partition plate 113 effectively seals adjacent heat exchange units.

[0068] In some embodiments, the partition plate 113 is provided with a limiting groove 1131 and a limiting tooth 1132; When the side walls of the two partition plates 113 at corresponding positions abut each other, the limiting grooves 1131 and limiting teeth 1132 of the two partition plates 113 mesh with each other.

[0069] like Figure 2As shown, the partition plate 113 adopts a staggered design. During assembly, when the side walls of the two partition plates 113 abut against each other, the limiting groove 1131 and the limiting tooth 1132 are combined to ensure the stability of the spacing between the two single plates 11, that is, the uniformity of the thickness of the heat exchange plate 1. During use, when the heat exchange plate 1 is squeezed, the two abutting partition plates 113 can move relative to each other in a staggered manner to eliminate the squeezing pressure. When applied in the battery pack, when the cell expands due to thermal runaway, the stress inside the battery pack can be eliminated by the deformation of the heat exchange plate 1 under pressure, thus delaying the time of cell ignition. Moreover, when the heat exchange plate 1 is squeezed and deformed, it will timely open the heat exchange channel 112 of the adjacent heat exchange unit, thereby avoiding the complete loss of heat exchange performance caused by the blockage of the heat exchange channel 112. The flow equalization channel 111 is integrally formed with the single plate 11. During squeezing, the flow equalization channel 111 deforms together with the single plate 11 and will not be affected or blocked. When the cell temperature drops, the internal stress is eliminated, and the single plate 11 can recover under its own elastic potential energy. The original limiting groove 1131 and limiting tooth 1132 re-combine to ensure the structural stability of the heat exchange plate 1, that is, the sealing stability between the internal heat exchange units.

[0070] In some cases, such as Figure 3 As shown, the inner wall of the flow equalization channel 111 is provided with a corrugated inner wall 1113, which further increases the specific surface area of ​​the inner wall of the flow equalization channel 111, that is, increases the heat exchange area and improves the heat exchange efficiency of the refrigerant in the flow equalization channel 111.

[0071] It should be noted that, in this application, the cross-sectional diameters of the flow equalization channel 111, the jet channel 1111, and the heat exchange channel 112 are all conventional dimensions in the art.

[0072] In some embodiments, at least partially, strain gauges 15 are provided on the outer sidewall of the single plate 11 for monitoring the normal deformation of the single plate 11.

[0073] By locally attaching strain gauges 15 to the outside of the single plate 11, the deformation of the single plate 11 can be measured without affecting the heat exchange of the single plate 11, so that users can perceive the expansion of the battery cell in real time. Example 3

[0074] This application also provides a fire extinguishing assembly for fire suppression of battery cells, used for extinguishing fires in battery cells; Fire extinguishing assemblies for battery cell fire suppression include: Fire detection tube 22; The connecting components 21 arranged at both ends of the flame detection tube 22 are used to connect and conduct the flame detection tube 22 to the refrigerant channel that transports refrigerant. The shield 23 is fixedly connected to the flame probe 22 and is used to shield the outer peripheral wall of the flame probe 22 so that the refrigerant inside the flame probe 22 has a fixed spray direction after it breaks.

[0075] like Figures 9-11 As shown, the fire detection tube 22 is made of heat-sensitive polymer materials (such as modified nylon or polypropylene). The inside is used to flow or is filled with fire extinguishing refrigerant (such as perfluorohexanone, heptafluoropropane or trifluoromethane) at a predetermined pressure. Under normal operating conditions, the fire detection tube 22 remains sealed. When it encounters local high temperature (usually 110℃-160℃), the tube wall of the heated part softens and bursts, automatically forming a release port, which quickly releases the internal refrigerant to the overheating or ignition point of the battery cell. With the help of the refrigerant's heat absorption, oxygen isolation and chemical reaction inhibition properties, the fire at the ignition point is effectively controlled in the early stage of the fire.

[0076] The connecting assembly 21 is used to connect the flame probe 22 to the refrigerant passage. It can be made of metal (such as brass or stainless steel) or flame-retardant engineering plastic. In some cases, the connecting assembly 21 is equipped with a sealing ring and a one-way valve to control the flow direction of the refrigerant in the flame probe 22.

[0077] The shield 23 is fixedly connected to the fire detection tube 22 and is used to shield the outer peripheral wall of the fire detection tube 22. The shield 23 is made of flame-retardant material (such as stainless steel sheet, aluminum alloy or flame-retardant nylon). By limiting the refrigerant injection angle by the shield 23, the refrigerant is concentrated and sprayed towards the core area of ​​the burning battery cell (such as explosion-proof valve, electrode tab), avoiding the dispersion and waste of traditional omnidirectional spraying, improving the fire extinguishing efficiency by more than 50%, and effectively improving the utilization rate of refrigerant, which can reduce the overall refrigerant charging amount of the system and reduce the operating cost. At the same time, by guiding the refrigerant through the shield 23, the refrigerant is blocked from being sprayed onto adjacent healthy cells, preventing secondary thermal runaway caused by cold shock and protecting the overall safety of the battery pack.

[0078] Moreover, the shield 23 can provide physical protection for the fire detection tube 22, avoid mechanical damage to the fire detection tube 22, and improve the reliability of the fire extinguishing system.

[0079] In some embodiments, the shield 23 includes an integrally formed receiving area 231 and two sets of shields 232, with the receiving area 231 disposed between the two sets of shields 232; The containment area 231 is used to contain the fire probe 22, and the shield 232 is used to guide the direction of refrigerant spraying after the fire probe 22 is ruptured.

[0080] The receiving area 231 and the shielding cover 232 are integrally formed, avoiding loosening or misalignment caused by separate connection, and ensuring long-term stability of the spray direction; the two sets of shielding covers 232 are located on both sides of the fire detection tube 22, which can form a V-shaped or U-shaped guiding structure, so that the refrigerant is sprayed in two directions, such as the tab area on both sides of the top of the battery cell, to expand the effective fire extinguishing coverage area; moreover, after the fire detection tube 22 is inserted into the receiving area 231, the shielding cover 232 automatically positions itself at the correct angle without additional adjustment, reducing the assembly difficulty.

[0081] In some embodiments, the receiving area 231 is a groove with an arc-shaped bottom wall, and at least a portion of the outer peripheral wall of the fire probe 22 abuts against the arc-shaped bottom wall; The receiving area 231 is provided with several clips 233 at intervals along the length of the fire detection tube 22 for securing and fixing the fire detection tube 22.

[0082] The bottom wall of the groove in the receiving area 231 matches the circular cross-section of the fire detection tube 22, increasing the contact area and providing radial restraint for the fire detection tube 22, preventing the fire detection tube 22 from rolling or shifting within the receiving area 231, and ensuring that the relative position of the fire detection tube 22 and the shield 23 is fixed. The spaced-out clips 233 limit the fire detection tube 22 within the receiving area 231, preventing the fire detection tube 22 from slipping due to vibration or thermal expansion, thus meeting the usage requirements of vibration environments such as vehicle-mounted systems. The clips 233 have open ends and are arranged in sections, allowing the fire detection tube 22 to expand slightly at high temperatures without generating excessive stress, avoiding accidental breakage in non-fire conditions, thereby improving the reliability of the fire protection system.

[0083] In some embodiments, the planes of the two sets of shields 232 are at an obtuse angle, and the fire probe 22 is within the area enclosed by the angle.

[0084] The obtuse angle (e.g., 120°-150°) between the two sets of shields 232 allows the two sets of shields 232 to be in an open state. After the refrigerant is ejected from the rupture point of the flame probe 22, it flows obliquely downwards and to both sides along the inner wall of the shield 232, forming a fan-shaped spray surface that covers a wider area on the top of the battery cell. Compared with right angles or acute angles, the obtuse angle design reduces the eddy currents and energy loss of the refrigerant at the corners, allowing the refrigerant to be ejected at a higher speed, enhancing its ability to penetrate the gaps between the battery cells. This allows the refrigerant to act directly on the gaps between the battery cells, improving the heat dissipation capacity of the battery cell under thermal runaway conditions.

[0085] Meanwhile, the flame probe 22 is located within the angled enclosure area, and the shield 23 not only guides the refrigerant but also provides physical protection against external foreign objects, reducing the risk of accidental damage to the flame probe 22.

[0086] In some embodiments, the two ends of the shield 23 are respectively provided with hinge portions 234, and the hinge portions 234 and the corresponding positions of the connecting components 21 are provided with hinge holes 2341 and rotating shafts 214.

[0087] The shield 23 can rotate around the pivot 214 relative to the connecting assembly 21, so that the whole consisting of the fire probe 22 and the shield 23 can adapt to the top shape or installation angle deviation of different battery cells, ensuring that the spraying direction is always aligned with the battery cell; at the same time, the hinged structure design can compensate for minor deviations in the battery cell assembly process and avoid stress concentration caused by rigid connection.

[0088] In some embodiments, the hinge hole 2341 is an elliptical hole, and the major axis of the elliptical hole is aligned with the length direction of the shield 23 and / or the fire probe 22.

[0089] The elliptical hole allows the shield 23 to move a certain distance relative to the rotating shaft 214 along the length direction, i.e. the axial direction of the fire probe 22, to compensate for length changes caused by thermal expansion and contraction or manufacturing tolerances, and to prevent the fire probe 22 from bending under pressure or the connecting assembly 21 from becoming loose from the refrigerant channel.

[0090] Moreover, the gap between the elliptical hole and the rotating shaft 214 can absorb some of the vibration energy, reducing the risk of fatigue breakage of the fire probe 22 due to high-frequency vibration.

[0091] In some cases, during assembly, the connecting component 21 can be fixed first, and then the hinge hole 2341 of the cover 23 can be assembled with the rotating shaft 214 without precise alignment, thus reducing the difficulty of assembly.

[0092] In some embodiments, an elastic sleeve is provided between the peripheral wall of the rotating shaft 214 and the wall of the hinge hole 2341. The axial section of the elastic sleeve is an ellipse, and the major axis of the ellipse is consistent with the length direction of the shield 23 and / or the fire probe 22.

[0093] By setting an elastic sleeve (such as rubber or silicone material) between the rotating shaft 214 and the hinge hole 2341, the elastic sleeve undergoes elastic deformation during vibration or thermal expansion, providing cushioning; and after deformation, the elastic restoring force allows the mask 23 to return to its original position, maintaining the long-term stability of the spraying direction. Moreover, the elliptical elastic sleeve fills the gap between the hinge hole 2341 and the rotating shaft 214, preventing direct collision of metal parts from causing noise or wear, while allowing necessary axial sliding.

[0094] In some embodiments, the connecting component 21 is provided with a limiting protrusion 212 on the side opposite to the fire detection tube 22 for insertion and fixation with the refrigerant channel; The connecting assembly 21 also includes a fixing wing 215, which has a fixing hole for fixing to the refrigerant channel by bolts.

[0095] like Figure 6 and Figure 7As shown, the limiting protrusion 212 enables quick insertion and positioning, while the fixing wing 215 and bolts provide a secure and anti-loosening solution. Together, they enable rapid installation of the connecting assembly 21 and the refrigerant channel and stable connection under vibration conditions. The limiting protrusion 212 typically has a non-circular cross-section, such as rectangular or D-shaped. After being inserted into the corresponding groove of the refrigerant channel, it can prevent the connecting assembly 21 from rotating relative to the refrigerant channel, ensuring that the opening direction of the shield 23 always faces the battery cell. The insertion fit can provide pre-tightening force for the sealing ring, while the bolt fixation maintains a long-term compressed state to prevent refrigerant leakage. Example 4

[0096] This application also provides a battery pack, including battery cells and any one of the above-mentioned heat exchange plates 1 and / or fire extinguishing assemblies 2; The fire detector tube 22 is positioned horizontally above the battery cell, and the opening of the shield 23 faces the battery cell.

[0097] The flame detector tube 22 is located above the battery cell, and the shield 23 opens downwards towards the battery cell. After the refrigerant is sprayed out, it falls faster under the action of gravity, making it easier to enter the explosion-proof valve area of ​​the battery cell and improve the utilization rate of the refrigerant. The flame detector 22 is arranged across the battery cell, enabling it to accurately detect overheating of the battery cell and further improve the response rate.

[0098] The fire extinguishing assembly 2 is located on top of the battery cell or in the gap, without taking up extra side or bottom space, and is compatible with the compact design of current mainstream battery packs.

[0099] In some embodiments, the system further includes a plurality of heat exchange plates 1 arranged alternately with the battery cells and in contact with them for heat exchange, and a refrigerant channel is disposed on the heat exchange plates 1.

[0100] like Figure 6 As shown, the refrigerant channel is integrated inside the heat exchange plate 1. The heat exchange plate 1 is responsible for the daily heat dissipation of the battery cell and also serves as a refrigerant delivery pipeline when the battery cell overheats or catches fire, eliminating the need for a separate fire protection pipeline. At the same time, the heat exchange plate 1 and the battery cell are arranged alternately and in contact for heat exchange. The two ends of the fire detection tube 22 are connected to the adjacent heat exchange plate 1, thereby effectively shortening the length of the fire detection tube 22 and reducing the distance between the refrigerant channel and the ignition point, further improving the response rate. Moreover, the heat exchange plate 1 serves as both a refrigerant delivery pipeline for battery cell heat dissipation and fire extinguishing, achieving dual functions of heat dissipation and fire protection, reducing the pipeline layout within the system, and lowering the design difficulty and operating costs.

[0101] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0102] The direct cooling system and battery pack with fire extinguishing function provided by this invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make several improvements and modifications to this invention without departing from the principles of this invention, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A direct cooling system with fire extinguishing function for heat dissipation of battery cells, characterized in that, It includes a compressor, condenser, expansion valve and evaporator connected in series in a closed loop; The condenser and the expansion valve are connected in parallel with several branch channels, and several fire extinguishing assemblies (2) are connected between two adjacent branch channels. The fire extinguishing assembly (2) includes a fire detection tube (22) for laterally crossing the battery cell.

2. The direct cooling system with fire extinguishing function according to claim 1, characterized in that, Each of the branch channels is equipped with a pressure reduction component at its upstream end.

3. The direct cooling system with fire extinguishing function according to claim 1, characterized in that, The fire extinguishing assemblies (2) in different branch channel intervals are arranged alternately and staggered.

4. The direct cooling system with fire extinguishing function according to claim 1, characterized in that, The evaporator includes several heat exchange plates (1) for alternating arrangement and contact with the battery cell for heat exchange; The heat exchange plate (1) includes an upward channel (131), a downward channel (141) and several heat exchange channels (112). The upward channel (131) is connected to the condenser or the expansion valve; The downlink channel (141) is connected to the compressor; The heat exchange channel (112) connects the upward channel (131) and the downward channel (141).

5. The direct cooling system with fire extinguishing function according to claim 4, characterized in that, The evaporator also includes a liquid inlet pipe (3) and a gas return pipe (4); The upward channel (131) is connected to the liquid inlet pipe (3), and a pressure reducing component is provided at the connection point; The down channel (141) is connected to the return air pipe (4).

6. The direct cooling system with fire extinguishing function according to claim 4, characterized in that, The heat exchange plate (1) is provided with several plug-in sockets for detachable plug-in connection to the fire probe (22).

7. The direct cooling system with fire extinguishing function according to claim 6, characterized in that, The connector includes a snap-fit ​​groove (132) and a plug-in protrusion (1312), the plug-in protrusion (1312) being provided with a plug-in channel communicating with the uplink channel (131); The fire extinguishing assembly (2) further includes a connecting component (21), which is disposed at the end of the fire detection tube (22). The connecting component (21) includes a limiting protrusion (212) and a plug hole (213) communicating with the fire detection tube (22). The limiting protrusion (212) is engaged with the locking groove (132), and the insertion protrusion (1312) is in the insertion hole (213) to make the insertion channel communicate with the insertion hole (213).

8. The direct cooling system with fire extinguishing function according to claim 1, characterized in that, The fire extinguishing assembly (2) also includes a shield (23) for covering the fire detection tube (22) so that the internal medium of the fire detection tube (22) can be sprayed in a preset direction after the fire detection tube (22) is broken.

9. A battery pack, characterized in that, It includes several battery cells and a direct cooling system with fire extinguishing function as described in any one of claims 1-8.

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