Battery energy storage system thermal runaway mitigation device and method

Abstract

The application discloses a battery energy storage system thermal runaway inhibition device and method, wherein the device comprises a heat absorption layer and a flame retardant release layer; the heat absorption layer is arranged close to the outer side of the battery, and the flame retardant release layer is arranged on the side of the heat absorption layer away from the battery; the heat absorption layer is used for heat absorption when the battery thermal runaway temperature is 50-80 DEG C, so as to reduce the battery heat accumulation speed; the flame retardant release layer is used for releasing the flame retardant when the battery surface temperature and the combustible gas concentration are controlled within the preset safety range after the heat absorption layer reduces the battery heat accumulation speed, so as to inhibit the combustible gas combustion reaction generated by the battery heating. The embodiment can significantly reduce the risk of the battery ignition or fire spreading caused by the thermal runaway by reducing the battery temperature rising rate through the heat absorption layer and effectively inhibiting the combustible gas combustion reaction in combination with the flame retardant.

Description

Technical Field

[0001] This invention relates to the field of battery energy storage system safety protection technology, and in particular to a device and method for suppressing thermal runaway in battery energy storage systems. Background Technology

[0002] Battery thermal runaway is a complex chain reaction process in which a large amount of electrolyte vapor and flammable alkane gases are released inside the battery. These gases can be generated and accumulated in the temperature range of 60℃ to 80℃, and are easily ignited when exposed to open flames or high temperatures, thus triggering a violent exothermic reaction.

[0003] When transitioning from the initial stage of thermal runaway to the early stage of thermal runaway initiation, the temperature rise rate can rapidly increase to 5-8°C / min once thermal runaway is initiated, entering a rapid heat accumulation phase. Existing passive fire extinguishing devices mostly rely on high-temperature triggering (e.g., perfluorohexanone fire extinguishers require ≥120°C to activate), making active intervention impossible in the critical temperature range of 60°C-80°C. This often misses the early suppression window of 50°C-80°C, making it difficult to prevent rapid heat accumulation, leading to the generation and spread of large amounts of flammable gas, and consequently, the spread of the fire. Summary of the Invention

[0004] This invention provides a thermal runaway suppression device and method for battery energy storage systems, which addresses the problem that existing passive fire extinguishing devices often rely on high-temperature triggering, cannot achieve active intervention in the critical temperature range, often miss the early suppression window, and are unable to prevent the rapid accumulation of heat, leading to the generation and spread of a large amount of combustible gas, and thus the spread of fire.

[0005] The present invention provides a thermal runaway suppression device for a battery energy storage system, comprising a heat-absorbing layer and a flame retardant release layer, wherein the heat-absorbing layer is disposed close to the outer side of the battery, and the flame retardant release layer is disposed on the side of the heat-absorbing layer away from the battery;

[0006] The heat-absorbing layer is used to absorb heat when the battery thermal runaway temperature is 50℃~80℃ to reduce the rate of battery heat accumulation. The flame retardant release layer is used to release flame retardant after the heat-absorbing layer reduces the rate of battery heat accumulation and when the battery surface temperature and combustible gas concentration are controlled within a preset safety range, so as to suppress the combustion reaction of combustible gas generated by battery heating.

[0007] Furthermore, the heat-absorbing layer is a phase change material layer.

[0008] Furthermore, the phase change material layer comprises a composite phase change material formed from octadecane and expanded graphite.

[0009] Furthermore, the flame retardant release layer includes a silicone rubber matrix, microcapsules, and a flame retardant encapsulated inside the microcapsules; the microcapsules are dispersed and bonded within the silicone rubber matrix to form a coating structure.

[0010] Furthermore, the wall material of the microcapsule includes melamine-formaldehyde resin.

[0011] Furthermore, the flame retardant material includes red phosphorus.

[0012] Furthermore, it also includes a heat dissipation layer disposed on the side of the flame retardant release layer away from the battery. The heat dissipation layer is used to dissipate heat from the heat absorption layer and the flame retardant release layer after the flame retardant is released from the flame retardant release layer.

[0013] Furthermore, the heat dissipation layer includes a microchannel network, the channels of which are filled with nanofluid, and the power device is used to enable the nanofluid to flow within the channels.

[0014] Furthermore, it also includes a high-temperature resistant epoxy resin adhesive layer, which is disposed between the flame retardant release layer and the heat dissipation layer.

[0015] This invention also provides a thermal runaway suppression method based on the thermal runaway suppression device of the battery energy storage system, comprising:

[0016] S1. When the battery thermal runaway temperature is 50℃~80℃, the heat-absorbing layer absorbs heat to reduce the rate of battery heat accumulation.

[0017] S2. After the heat-absorbing layer reduces the rate of battery heat accumulation, and the battery surface temperature and combustible gas concentration are controlled within a preset safe range, the flame retardant release layer releases flame retardant to suppress the combustion reaction of combustible gas generated by battery heating.

[0018] As can be seen from the above technical solutions, the present invention has the following advantages: In this embodiment, the heat-absorbing layer is disposed close to the battery surface, and heat absorption is initiated first in the early stage of thermal runaway, reducing the rate of heat accumulation in the battery, rapidly slowing down the rate of temperature rise in the battery, and inhibiting the rapid generation and accumulation of combustible gases; the flame retardant release layer is disposed on the side of the heat-absorbing layer away from the battery. After the heat-absorbing layer reduces the rate of heat accumulation in the battery, the heat-absorbing layer has completed the initial temperature control of the battery, and when the battery surface temperature and the concentration of combustible gases in the system are controlled within a preset safe range, the flame retardant release layer is activated, precisely acting on the combustible mixture within the controllable range to inhibit the combustion reaction of combustible gases. The layered arrangement design of the heat-absorbing layer and the flame retardant release layer in this embodiment creates a relatively stable thermal environment for the outer flame retardant release layer, avoiding premature decomposition or failure of the flame retardant due to the instantaneous impact of high-temperature heat flow. Therefore, this embodiment, by reducing the rate of temperature rise in the battery through the heat-absorbing layer and effectively inhibiting the combustion reaction of combustible gases in combination with the flame retardant, can significantly reduce the risk of battery fire or fire spread due to thermal runaway. Attached Figure Description

[0019] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a thermal runaway suppression device for a battery energy storage system provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the distribution structure of the heat-absorbing layer, flame retardant release layer, and heat dissipation layer in a battery energy storage system thermal runaway suppression device provided in an embodiment of the present invention;

[0022] Figure 3 This is a schematic flowchart of a thermal runaway suppression method based on a thermal runaway suppression device for a battery energy storage system, provided by an embodiment of the present invention.

[0023] Explanation of reference numerals in the attached diagram: 1. Battery; 2. Heat-absorbing layer; 3. Flame retardant release layer; 4. Heat dissipation layer. Detailed Implementation

[0024] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0025] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the present application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] Please see Figure 1-2This invention provides a thermal runaway suppression device for a battery energy storage system, including a heat-absorbing layer 2 and a flame retardant release layer 3. The heat-absorbing layer 2 is disposed near the outside of the battery 1, and the flame retardant release layer 3 is disposed on the side of the heat-absorbing layer 2 away from the battery 1.

[0027] The heat-absorbing layer 2 is used to absorb heat when the thermal runaway temperature of battery 1 is 50℃~80℃, so as to reduce the heat accumulation rate of battery 1. The flame retardant release layer 3 is used to release flame retardant after the heat-absorbing layer 2 reduces the heat accumulation rate of battery 1 and the battery surface temperature and combustible gas concentration are controlled within a preset safe range, so as to suppress the combustion reaction of combustible gas generated by the heat generation of battery 1.

[0028] Understandably, in this embodiment, the heat-absorbing layer 2 is positioned close to the surface of the battery 1. It initiates heat absorption in the early stages of thermal runaway, reducing the rate of heat accumulation in the battery 1, rapidly slowing down the temperature rise rate, and inhibiting the rapid generation and accumulation of combustible gases. The flame retardant release layer 3 is positioned on the side of the heat-absorbing layer 2 away from the battery 1. After the heat-absorbing layer 2 reduces the rate of heat accumulation in the battery 1, and has completed initial temperature control of the battery 1, keeping the surface temperature of the battery 1 and the concentration of combustible gases within the system within a preset safe range, the flame retardant release layer 3 is activated, precisely acting on the combustible mixture within the controllable range to inhibit the combustion reaction of the combustible gases. The layered arrangement of the heat-absorbing layer 2 and the flame retardant release layer 3 in this embodiment creates a relatively stable thermal environment for the outer flame retardant release layer 3, preventing premature decomposition or delayed response of the flame retardant due to the instantaneous impact of high-temperature heat flow. Therefore, this embodiment reduces the rate of temperature rise of battery 1 by using heat-absorbing layer 2 and effectively suppresses the combustion reaction of combustible gas by combining flame retardant, which can significantly reduce the risk of battery 1 catching fire or spreading fire due to thermal runaway.

[0029] In a more specific embodiment, the heat-absorbing layer 2 is used to absorb heat and reduce the rate of heat accumulation in the battery 1 when the temperature of the battery 1 reaches a first preset temperature, and the flame retardant releasing layer 3 is used to release flame retardant to inhibit the combustion reaction of combustible gas when the temperature of the battery 1 reaches a second preset temperature. The second preset temperature is greater than the first preset temperature, and both the first preset temperature and the second preset temperature are within the early suppression window of 50°C to 80°C.

[0030] It should be noted that in the early stages of thermal runaway, the internal reaction is violent, the rate of heat accumulation is too rapid, the temperature rises rapidly, and the heat cannot dissipate in time, resulting in the generation and accumulation of large amounts of flammable gas. Because the heat has already accumulated too much in the early stages and the reaction has been fully activated, even if a fire extinguisher is used to cool down the battery 1, the cooling rate is far slower than the rate at which the battery 1 releases heat and spreads the fire. Therefore, the cooling rate of the fire extinguisher in the later stages is insufficient to suppress the spread of the fire in the battery 1. Even if the trigger temperature threshold of the perfluorohexanone fire extinguisher is lowered to 60°C, it is still impossible to effectively suppress the early stages of thermal runaway. This is because the temperature rise rate of the battery 1 after thermal runaway is initiated can reach 5–8°C / min, and the cooling rate of the extinguishing agent is difficult to match the rate of heat release of the internal chain reaction, making it impossible to stop the heat accumulation and reaction spread in time. At the same time, since the temperature of the battery 1 will fluctuate during operation, lowering the trigger temperature threshold of the fire extinguisher to an even lower level would lead to waste of extinguishing materials, misjudgment of the fire extinguishing situation, and affect the normal operation of the battery 1.

[0031] Understandably, in this embodiment, the heat-absorbing layer 2 is positioned close to the surface of the battery 1. When a lower first preset temperature is reached, the battery 1 absorbs heat to reduce the rate of heat accumulation, quickly slowing down the temperature rise and preventing the rapid accumulation of flammable gas. In this embodiment, the flame retardant release layer 3 is positioned away from the surface of the battery 1, outside the heat-absorbing layer 2. When the temperature of the battery 1 reaches a higher second preset temperature, the flame retardant release layer 3 activates to release the flame retardant. At this time, under the action of the heat-absorbing layer 2, the initial temperature control of the battery 1 has been completed, and the flammable gas is within a controllable range. The flame retardant can act precisely on the flammable gas, forming a chemically isolated flame-retardant barrier from the source. This avoids both premature release of the flame retardant leading to waste and delayed release missing the optimal suppression opportunity in the early stages of thermal runaway.

[0032] In this embodiment, the heat-absorbing layer 2 provides initial thermal management for the battery 1, ensuring that the temperature of the battery 1 is controlled within a preset range and the concentration of combustible gas is maintained within a safe range. This creates conditions for the precise activation of the flame retardant release layer 3. The flame retardant is precisely released when the temperature of the battery 1 reaches a relatively stable second preset temperature, avoiding both missing the early inhibition window due to late release and ineffective consumption of the agent due to premature release.

[0033] Without the effective suppression of heat accumulation rate by the heat-absorbing layer 2, the battery 1 will remain at the second preset temperature for an extremely short time during the temperature rise. Even if the flame retardant release is triggered at this point, the rapid temperature increase significantly accelerates the generation and accumulation rate of combustible gases. The release and diffusion rate of the flame retardant cannot match the temperature rise rate and the increase in combustible gas concentration, resulting in the flame-retardant barrier failing to cover and suppress the combustible gases in a timely and effective manner. This is essentially equivalent to missing the critical early suppression window, significantly reducing or even eliminating the flame-retardant effect. Furthermore, unlike existing technologies that simply mix the flame retardant release material with the heat-absorbing material, this embodiment uses a layered, independent design to prevent the flame retardant release material from prematurely breaking down and releasing during the continuous heat absorption process of the heat-absorbing layer 2. This design ensures that the flame retardant does not fail prematurely in the early stages of thermal runaway, but rather exerts its maximum suppression effect when the battery 1 temperature reaches the second preset temperature relatively stably, at the most critical moment for flame retardant requirements.

[0034] It should be further explained that after the flame retardant in this embodiment suppresses the combustible gas, the heat-absorbing layer 2 can continue to absorb the heat generated by the flame retardant reaction, forming a synergistic cycle of "temperature control-gas suppression-temperature control". The heat-absorbing layer 2 continuously provides a stable temperature environment for the flame retardant release layer 3, making the protection logic more coherent and the protection effect more stable.

[0035] In summary, this embodiment achieves enhanced heat dissipation and prevents heat accumulation within the effective temperature control range of the heat-absorbing layer 2 by continuously delaying the temperature rise efficiency and accurately releasing flame retardants to effectively suppress the combustion reaction. This further reduces the rate of temperature rise, slows down the release rate of flammable gases, and effectively reduces the risk of battery 1 ignition and fire spread.

[0036] In a more specific embodiment, the first preset temperature is 56°C to 60°C, and the second preset temperature is 70°C.

[0037] It is understandable that the first preset temperature of 56℃~60℃ and the second preset temperature of 70℃ are both within the early suppression window of 50℃~80℃. This allows for the suppression of the heat accumulation rate and the flammable gas accumulation rate within the early suppression window, which can significantly reduce the risk of battery 1 catching fire or the spread of fire due to thermal runaway.

[0038] It should be noted that the second preset temperature of 70°C is the preset safety threshold temperature for the release of flame retardant from the flame retardant release layer. When the battery surface temperature reaches 70°C, the concentration of flammable gas produced is within a safe range, for the following reasons:

[0039] According to the paper "Operando monitoring of thermal runaway in commercial lithium-ion cells via advanced lab-on-fiber technologies" (Nature Communications, 2023): "Safety runaway stage (I): After the heater is turned on, heat rapidly increases the surface temperature of the battery through thermal conduction. Due to the low thermal conductivity of the battery, the surface temperature is generally higher than the internal temperature. In the first 100 seconds or so, the internal pressure of the battery is stable at about 0.1 MPa (pressure equilibrium state); when the temperature rises further to about 70°C, the electrolyte evaporates, causing the internal pressure to begin to rise. Subsequently, the solid-liquid electrolyte interface (SEI) film begins to decompose, releasing oxygen, carbon dioxide, and ethylene in sequence, causing the internal pressure to rise significantly." From the above research results, it can be concluded that when the battery temperature rises to about 70°C, it is in the safe runaway stage, and the concentration of combustible gases is within an absolutely safe and controllable range.

[0040] In a more specific embodiment, the heat-absorbing layer 2 is a phase change material layer.

[0041] It is understood that, in specific implementation, the heat-absorbing layer 2 of this embodiment adopts a phase change material layer. When the temperature of battery 1 rises, the phase change material layer absorbs the latent heat of phase change, achieves efficient heat storage, and delays the temperature rise. Therefore, in the early suppression window of thermal runaway (50℃~80℃), the phase change material layer of this embodiment effectively suppresses the temperature rise rate after the start of thermal runaway of battery 1 by absorbing heat, stabilizes the thermal environment, and creates a time window for the flame retardant reaction of the flame retardant.

[0042] It should be noted that phase change materials (PCMs) can absorb a large amount of latent heat of phase change, rather than sensible heat, within their phase change temperature range. Compared to sensible heat storage materials, PCMs can absorb a large amount of heat at a near-constant temperature, effectively curbing the rapid rise in battery 1 temperature in the early stages of thermal runaway and providing valuable response time for subsequent protective measures. By selecting PCMs with specific phase change temperatures, the heat-absorbing layer 2 can only begin to absorb a large amount of heat when the battery 1 temperature exceeds a safety threshold, achieving "on-demand activation." This passive, self-triggered characteristic avoids unnecessary energy loss and ensures the accuracy and reliability of the thermal management system. Because PCMs can "pinch" the surface temperature of battery 1 near its phase change temperature, they significantly reduce the rates of thermal shrinkage of the battery 1 separator, electrolyte decomposition, and gas generation. This inhibits the rapid accumulation of combustible gases at the source, maintaining the concentration of combustible gases within the system within a controllable range, creating a stable thermal environment and concentration window for the precise intervention of the flame retardant release layer 3.

[0043] In a more specific embodiment, the phase change material layer comprises a composite phase change material formed from octadecane and expanded graphite.

[0044] It is understandable that, in specific implementation, the phase change material layer in this embodiment uses an organic phase change material, octadecane (phase change temperature 56℃~60℃, latent heat of phase change 240kJ / kg), combined with expanded graphite to improve thermal conductivity (thermal conductivity increased to 3.5W / kg). The coating is evenly applied to the surface of battery 1 with a thickness of about 0.3-0.5 mm. When the temperature of battery 1 rises, it absorbs the latent heat of phase change and delays the temperature rise.

[0045] It should be noted that the expanded graphite in this embodiment mainly serves to enhance thermal conductivity, provide structural support, and resist oxidation. If the expanded graphite is removed, the thermal conductivity of the phase change material layer will decrease, heat cannot be quickly dissipated, and local overheating is likely to occur; the mechanical strength of the coating will also decrease, making it prone to cracking and peeling off at high temperatures, thus affecting the protective effect.

[0046] In a more specific embodiment, the flame retardant release layer 3 includes a silicone rubber matrix, microcapsules, and a flame retardant encapsulated inside the microcapsules; the microcapsules are dispersed and bonded to the silicone rubber matrix to form a coating structure.

[0047] Understandably, in this embodiment, the flame retardant release layer 3 adopts a composite coating structure of "silicone rubber matrix-microcapsule-flame retardant". The flame retardant is pre-encapsulated inside the microcapsules and uniformly dispersed and combined with the silicone rubber matrix through the microcapsules to form a stable functional coating. This structure utilizes the physical barrier effect of the microcapsules to achieve delayed and controlled release of the flame retardant: in the early stage of thermal runaway, the microcapsules effectively prevent the flame retardant from contacting the external environment, avoiding premature loss or failure due to high-temperature preheating or physical compression; only when the heat-absorbing layer 2 completes the initial temperature control and the battery 1 temperature stabilizes and reaches the trigger threshold, the microcapsule wall material ruptures under thermal action, and the flame retardant can be accurately released and act on the combustible gas within a controllable range. This design ensures that the flame retardant exerts maximum inhibition efficiency in the critical stage and avoids premature consumption of the agent, significantly improving the response accuracy and long-term reliability of the flame retardant release layer 3.

[0048] It should be noted that the flame retardant release layer 3 in this embodiment is a microcapsule flame retardant layer. The microcapsule flame retardant layer has a trigger temperature of 70°C. When the microcapsules rupture, they release the flame retardant, which chemically isolates the initially generated combustible gas, inhibits the combustion reaction, and eliminates the risk of combustion and explosion at the source.

[0049] In a more specific implementation, the microcapsules are made from melamine-formaldehyde resin to prepare the wall material.

[0050] Understandably, in practical implementation, melamine-formaldehyde resin materials possess advantages such as high mechanical strength, good thermal stability, and strong sealing properties, ensuring that the flame retardant is effectively sealed during storage and the initial stage of thermal runaway, preventing premature leakage and failure. When the temperature of battery 1 reaches the microcapsule rupture threshold (approximately 70°C), the wall material responds rapidly and undergoes irreversible rupture, achieving instantaneous directional release of the flame retardant. This rupture threshold highly matches the early stage of thermal runaway after the heat-absorbing layer 2 has completed initial temperature control—at this point, the surface temperature of battery 1 has been clamped within a safe range by the heat-absorbing layer 2, the concentration of combustible gas is within a controllable range, and the precise release of the flame retardant can act on the gas phase or condensed phase in a timely manner, effectively suppressing the combustion chain reaction. Through the dual synergistic mechanism of "heat-absorbing layer 2 temperature control + microcapsule temperature-controlled triggering," this embodiment achieves graded and precise intervention throughout the entire thermal runaway process, significantly improving the reliability and environmental adaptability of the battery 1 thermal protection system.

[0051] In a more specific implementation, the flame retardant is red phosphorus flame retardant.

[0052] Understandably, microcapsules (5-10 μm in particle size) are formed by encapsulating red phosphorus flame retardant and mixing them with a silicone rubber matrix to form a coating approximately 0.2-0.3 mm thick. When the temperature reaches the microcapsule rupture threshold (70°C), the flame retardant is released to inhibit the combustion reaction. After the red phosphorus is released at 70°C, it forms a polymetaphosphate separator film that covers the surface of battery 1, isolating oxygen and inhibiting the generation of flammable gases, achieving a flame retardant efficiency of UL94V-0 and preventing the spread of flame.

[0053] Red phosphorus is activated at 70°C and gradually releases its active phosphorus components. Through oxidation, dehydration, and polymerization reactions, a continuous and dense poly(p-phosphoric acid) glassy barrier film is rapidly formed on the material surface. This barrier film effectively blocks oxygen and heat transfer, inhibits the escape of combustible gases, and catalyzes the dehydration of the substrate into char. It constructs a dense and stable carbon-phosphorus composite protective layer on the material surface, further enhancing the physical barrier effect and reducing the generation of combustible decomposition products. This weakens the material basis for continuous combustion at the source, thereby blocking the combustion chain reaction and achieving a highly efficient flame retardant effect.

[0054] The synergistic effect of phase change materials and microcapsule flame-retardant layers reduces the thermal conductivity of battery 1 by 75% compared to traditional single heat insulation or flame-retardant materials, achieving a UL94V-0 flame-retardant rating. This effectively blocks the heat spread path and significantly improves the safety protection level of battery 1 module. This solution specifies a microcapsule particle size of 5-10μm and a rupture threshold of 70℃. The release sequence of red phosphorus flame retardant is precisely matched with the phase change material layer (activated at 56℃~60℃), forming a "temperature control first, then flame suppression" logic. Furthermore, the flame-retardant mechanism is clearly defined as the formation of a poly(methionine phosphoric acid) separator.

[0055] In a more specific embodiment, a heat dissipation layer 4 is also included, which is disposed on the side of the flame retardant release layer 3 away from the battery 1. The heat dissipation layer 4 is used to conduct heat away from the heat absorption layer 2 and the flame retardant release layer 3 after the flame retardant is released from the flame retardant release layer 3.

[0056] Understandably, in practice, a temperature gradient is formed from the inside out: "heat absorption layer 2 - flame retardant release layer 3 - heat dissipation layer 4". The high temperature on the surface of battery 1 is first absorbed by the heat absorption layer 2, then suppressed by the flame retardant release layer 3, and finally quickly dissipated by the heat dissipation layer 4, achieving a step-by-step reduction of heat, with greater thermal conduction resistance and better heat spread suppression effect.

[0057] It should be noted that the phase change heat absorption layer 2 primarily stores heat temporarily through latent heat of phase change, and it has its own saturation limit. If the heat cannot be dissipated in time, the phase change material will lose its thermal buffering capacity after complete phase change, and the heat will continue to be transferred to the interior of battery 1 and adjacent cells. The intervention of the heat dissipation layer 4 aims to directionally dissipate the accumulated heat to the external environment through thermal convection or thermal conduction, achieving the final dissipation of thermal energy, thereby breaking the energy basis for the continuous deterioration of thermal runaway. Although the flame retardant inhibits the combustion reaction of flammable gases, the high temperature inside battery 1 may still cause the electrolyte to continue to decompose, the separator to further shrink, or the positive and negative electrode materials to undergo thermal decomposition. If the temperature is not cooled in time, these side reactions will continuously generate new flammable gases, causing the formed flame retardant barrier to fail due to continuous high temperature impact. The heat dissipation channel can effectively inhibit the continuous occurrence of side reactions by reducing the temperature of battery 1, creating a long-lasting low-temperature stable environment for the flame retardant release layer 3. After the thermal runaway is initially controlled, if the interior of battery 1 is still in a high-temperature state, once new flammable gases are generated and encounter oxygen, it is very likely that reignition will occur. The heat dissipation layer 4 can ensure that the temperature of battery 1 continues to drop below the safety threshold, cut off the regeneration cycle of thermal runaway, and prevent heat from being transferred to adjacent cells, thus avoiding module-level thermal propagation accidents.

[0058] In a more specific embodiment, the heat dissipation layer 4 includes a microchannel network, the channels of which are filled with nanofluid, and a power device is connected to the channels to enable the flow of the nanofluid within the channels.

[0059] Understandably, in practice, the heat dissipation layer 4 adopts a microchannel structure. A microchannel network is directly formed on the bonding layer or a dedicated metal / high thermal conductivity ceramic substrate using photolithography on a copper substrate. The channel width is 0.3 mm, the depth is 0.2 mm, and the spacing is uniformly distributed. The interior is filled with nanofluid. When the temperature of battery 1 exceeds 80°C, the fluid is circulated by a power device, and the flow rate is controlled at 0.5-1.0 mL / min. This efficiently dissipates heat and enhances heat dissipation, preventing heat accumulation. The microchannel network is directly coupled with the heat absorption layer 2 and the flame retardant release layer 3 coating to form a closed loop of "heat absorption-flame retardancy-heat dissipation". This integrated design allows the heat absorbed from the phase change material layer to be introduced into the nanofluid in the microchannel network with the shortest path and lowest thermal resistance. This achieves the physical unity of the "heat absorption interface" and the "heat dissipation channel", completely eliminating the contact thermal resistance and response hysteresis problems of traditional independent cooling layers.

[0060] In a more specific embodiment, the power device is a miniature piezoelectric pump.

[0061] In a more specific embodiment, the nanofluid employs Nanofluids, working in synergy with the composite coating to dissipate heat, further reduce the temperature of battery 1.

[0062] Using nanofluids as a heat dissipation medium improves heat dissipation efficiency: The microchannel network in this solution is filled with... Compared to traditional coolants, nanofluids have higher thermal conductivity and better heat exchange efficiency. In emergency heat dissipation mode, they can quickly dissipate heat and form a highly efficient synergy with the phase change material layer and flame retardant release layer 3.

[0063] In a more specific embodiment, an adhesive layer is provided between the heat dissipation layer 4 and the flame retardant release layer 3.

[0064] Understandably, in specific implementation, this solution uses a high-temperature resistant epoxy resin adhesive layer, which not only achieves a firm bond between the coatings and between the coatings and the surface of battery 1, but also serves as the substrate for the microchannel network of the heat dissipation layer 4, realizing the integrated functions of bonding, support, and heat conduction. The temperature resistance range is -40℃ to 180℃, which is suitable for the complex working environment of the battery 1 energy storage system.

[0065] This invention provides a thermal runaway suppression method based on the above-mentioned battery energy storage system thermal runaway suppression device, comprising:

[0066] S1. In the early stage of thermal runaway of battery 1, the heat-absorbing layer 2 absorbs heat to reduce the rate of heat accumulation of battery 1.

[0067] S2. After the heat absorption layer 2 reduces the heat accumulation rate of battery 1, the flame retardant release layer 3 releases flame retardant in response to the reduction in the heat accumulation rate of battery 1, so as to suppress the combustion reaction of combustible gas generated by the heat generation of battery 1.

[0068] Understandably, in this embodiment, the heat-absorbing layer 2 is positioned close to the surface of the battery 1. It initiates heat absorption in the early stages of thermal runaway, reducing the rate of heat accumulation in the battery 1, rapidly slowing down the temperature rise rate, and inhibiting the rapid generation and accumulation of combustible gases. The flame retardant release layer 3 is positioned on the side of the heat-absorbing layer 2 away from the battery 1. After the heat-absorbing layer 2 reduces the rate of heat accumulation in the battery 1, and has completed initial temperature control of the battery 1, keeping the surface temperature of the battery 1 and the concentration of combustible gases within the system within a preset safe range, the flame retardant release layer 3 is activated, precisely acting on the combustible mixture within the controllable range to inhibit the combustion reaction of the combustible gases. The layered arrangement of the heat-absorbing layer 2 and the flame retardant release layer 3 in this embodiment creates a relatively stable thermal environment for the outer flame retardant release layer 3, preventing premature decomposition or delayed response of the flame retardant due to the instantaneous impact of high-temperature heat flow. Therefore, this embodiment reduces the rate of temperature rise of battery 1 by using heat-absorbing layer 2 and effectively suppresses the combustion reaction of combustible gas by combining flame retardant, which can significantly reduce the risk of battery 1 catching fire or spreading fire due to thermal runaway.

[0069] Please see Figure 3 This invention provides a thermal runaway suppression method based on the above-mentioned battery energy storage system thermal runaway suppression device, which achieves temperature adaptive response through a three-level linkage mechanism:

[0070] 1) Heat absorption in the early stage of thermal runaway (50℃~80℃): When the temperature of battery 1 rises to the phase transition temperature of the phase change material (56℃~60℃) due to overcharging, overheating, or other reasons, the phase change material layer undergoes a phase transition, absorbing a large amount of heat and maintaining the surface temperature of battery 1 at a relatively stable level, thus delaying the thermal runaway process. For example, in the early stage of thermal runaway, the phase change material can absorb about 80% of the additional heat, reducing the rate of temperature rise of battery 1 by 60%.

[0071] 2) Intelligent flame-retardant start-up (70℃): When the temperature continues to rise to 70℃, the microcapsules of the microcapsule flame-retardant layer rupture, releasing red phosphorus flame retardant. Red phosphorus generates polymetaphosphoric acid at high temperature, which covers the surface of battery 1 to form an isolation film, isolating oxygen and inhibiting the generation of combustible gases, thus preventing the spread of flame.

[0072] Understandably, compared to existing technologies where flame retardant materials and phase change materials are mixed in one layer, the flame retardant release timing in this embodiment is superior. In this embodiment, the release is delayed by the phase change material, preventing sudden temperature increases from affecting the release and action of the flame retardant, thus ensuring effective release and flame retardant effect. In contrast, existing technologies where flame retardant materials and phase change materials are mixed in one layer may result in asynchronous or premature release of the flame retardant, affecting its reaction performance.

[0073] 3) Enhanced Synergistic Heat Dissipation (≥80℃): The microchannel network of the auxiliary heat dissipation structure works continuously throughout the process, removing some heat through coolant circulation. This, combined with the composite coating, further reduces the temperature of Battery 1. When the temperature of Battery 1 exceeds 80℃, an emergency heat dissipation mode is automatically activated. The microchannel network initiates nanofluid circulation at a flow rate controlled at 0.5-1.0 mL / min to dissipate heat and prevent its accumulation.

[0074] It is understandable that by using phase change materials to effectively slow down the heating rate and using microcapsule flame retardant layers to effectively retard the flame, sufficient time is provided for the effective heat dissipation of heat dissipation layer 4, preventing heat accumulation.

[0075] The beneficial effects of the above embodiments are as follows:

[0076] 1. Active thermal runaway suppression: The phase change material layer actively absorbs heat in the early stage of thermal runaway. Compared with traditional passive suppression methods, it can curb the development of thermal runaway 1-2 minutes earlier and effectively reduce the probability of thermal runaway. Traditional passive methods (such as perfluorohexanone) require a temperature ≥120℃ to trigger.

[0077] 2. High-efficiency heat insulation and flame retardancy: The phase change material layer and the microcapsule flame retardant layer work together to reduce the heat conduction efficiency between batteries by 75% compared with traditional single heat insulation or flame retardant materials. The flame retardant effect reaches UL94V-0 level, effectively blocking the heat spread path and significantly improving the safety protection level of battery module 1.

[0078] 3. Multi-functional protection: It integrates multiple protection functions such as active heat absorption, intelligent flame retardancy, and thermal runaway gas suppression, which solves the technical defects of traditional materials with single functions, comprehensively covers the risk points of thermal runaway of battery 1 throughout the entire cycle, and greatly reduces the accident rate and the degree of loss.

[0079] 4. The phase change material layer and the microcapsule flame retardant layer adopt a standardized coating process, which can be seamlessly integrated into the existing battery 1 production process; the auxiliary heat dissipation structure of the heat dissipation layer 4 is modularly designed, which is convenient to install and does not require large-scale modification of the existing energy storage system. The implementation cost is reduced by more than 30%, which has extremely high industrial application value.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A thermal runaway suppression device for a battery energy storage system, characterized in that, It includes a heat-absorbing layer and a flame retardant release layer, wherein the heat-absorbing layer is disposed near the outer side of the battery, and the flame retardant release layer is disposed on the side of the heat-absorbing layer away from the battery; The heat-absorbing layer is used to absorb heat when the battery thermal runaway temperature is 50℃~80℃ to reduce the rate of battery heat accumulation. The flame retardant release layer is used to release flame retardant after the heat-absorbing layer reduces the rate of battery heat accumulation and when the battery surface temperature and combustible gas concentration are controlled within a preset safety range, so as to suppress the combustion reaction of combustible gas generated by battery heating.

2. The thermal runaway suppression device for a battery energy storage system according to claim 1, characterized in that, The heat-absorbing layer is a phase change material layer.

3. The thermal runaway suppression device for a battery energy storage system according to claim 2, characterized in that, The phase change material layer comprises a composite phase change material formed from octadecane and expanded graphite.

4. The thermal runaway suppression device for a battery energy storage system according to claim 1, characterized in that, The flame retardant release layer includes a silicone rubber matrix, microcapsules, and a flame retardant encapsulated inside the microcapsules; the microcapsules are dispersed and bonded to the silicone rubber matrix to form a coating structure.

5. The thermal runaway suppression device for a battery energy storage system according to claim 4, characterized in that, The wall material of the microcapsules includes melamine-formaldehyde resin.

6. The thermal runaway suppression device for a battery energy storage system according to claim 5, characterized in that, The flame retardant is made of red phosphorus.

7. A thermal runaway suppression device for a battery energy storage system according to claim 2 or 3, characterized in that, It also includes a heat dissipation layer, which is disposed on the side of the flame retardant release layer away from the battery. The heat dissipation layer is used to dissipate the heat of the heat absorption layer and the flame retardant release layer after the flame retardant is released from the flame retardant release layer.

8. The thermal runaway suppression device for a battery energy storage system according to claim 7, characterized in that, The heat dissipation layer includes a microchannel network, the channels of which are filled with nanofluid. The channels are connected to a power device, which is used to enable the nanofluid to flow within the channels.

9. A thermal runaway suppression device for a battery energy storage system according to claim 8, characterized in that, It also includes a high-temperature resistant epoxy resin adhesive layer, which is disposed between the flame retardant release layer and the heat dissipation layer.

10. A method for suppressing thermal runaway based on the thermal runaway suppression device of the battery energy storage system according to any one of claims 1-9, characterized in that, include: S1. When the battery thermal runaway temperature is 50℃~80℃, the heat-absorbing layer absorbs heat to reduce the rate of battery heat accumulation. S2. After the heat-absorbing layer reduces the rate of battery heat accumulation, and the battery surface temperature and combustible gas concentration are controlled within a preset safe range, the flame retardant release layer releases flame retardant to suppress the combustion reaction of combustible gas generated by battery heating.

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