A permeable liquid cooling battery heat dissipation system with self-sealing function

Abstract

This invention relates to the field of battery thermal management technology and discloses a permeable liquid-cooled battery heat dissipation system with self-sealing function, including a permeable layer, a sealing layer, and a coolant circulation system. The permeable layer is an open-cell foamed rubber layer directly attached to the surface of the battery cell. The open-cell foamed rubber layer has three-dimensional interconnected channels inside, which form microchannels for coolant permeation and flow. The sealing layer is a closed-cell foamed rubber layer tightly wrapped around the outside of the permeable layer. The closed-cell foamed rubber layer is a completely water- and air-impermeable elastic sealing structure. The coolant circulation system is connected to the microchannels of the permeable layer through pipelines to achieve heat exchange of coolant circulation within the microchannels. By using the natural three-dimensional interconnected channels of the open-cell foamed rubber as coolant microchannels, the coolant can directly permeate and flow inside the rubber tightly attached to the battery cell, achieving direct heat exchange between the coolant and the battery cell surface at zero distance.

Description

Technical Field

[0001] This invention relates to the field of battery thermal management technology, specifically to a permeation-type liquid-cooled battery heat dissipation system with a self-sealing function. Background Technology

[0002] With the rapid development of new energy vehicles and electrochemical energy storage technologies, the energy density and charge / discharge power of lithium-ion batteries continue to improve. Batteries generate a large amount of heat when operating at high rates. If this heat cannot be dissipated efficiently and in a timely manner, it will lead to excessively high battery temperatures, uneven temperature distribution, and consequently, capacity decay, shortened cycle life, and even safety issues such as thermal runaway. Therefore, an efficient, stable, and safe thermal management system has become an indispensable core component of lithium-ion battery systems.

[0003] The battery liquid cooling technology widely used in the industry today mainly uses a metal liquid cooling plate as the core carrier. It is usually made of metal materials such as aluminum alloy to form the flow channel, or a metal tube is embedded in the metal plate to form a cooling flow channel. The liquid cooling plate is attached to the surface of the battery cell through thermal interface materials such as thermal conductive gel and thermal conductive silicone pad. The coolant circulates inside the metal flow channel to achieve heat transfer through indirect contact. Traditional liquid cooling structures rely on metal channels and interface materials for heat exchange. While they possess a certain heat dissipation capacity, they have several inherent drawbacks: First, there is significant contact thermal resistance between the thermally conductive interface material, the battery cell, and the metal liquid cooling plate, resulting in a long heat transfer path and significant losses, making it difficult to meet the rapid heat dissipation requirements of high-power batteries. Second, the metal channel processing technology is complex and costly, and there is a risk of coolant corrosion and pipe rupture leading to leakage during long-term use. Once coolant leaks, it will directly cause safety hazards such as short circuits and battery cell failure. Third, the metal liquid cooling plate is rigid and cannot adapt to the thermal expansion and contraction deformation of the battery cell during charging and discharging, which can easily lead to increased bonding gaps and reduced heat dissipation performance. At the same time, it lacks buffer protection capabilities and is prone to mechanical damage to the battery cell under vibration conditions.

[0004] To further improve heat exchange efficiency, the industry is gradually moving towards direct cooling methods that directly combine the cooling medium with the heat-conducting structure, attempting to shorten the heat transfer path and reduce thermal resistance. However, existing direct cooling structures generally suffer from poor sealing reliability, relying mostly on independent sealing components such as sealing rings and sealants to prevent leakage. Under long-term pressure cycling, temperature fluctuations, and mechanical vibration, these seals are prone to aging and failure, failing to fundamentally solve the coolant leakage problem. Furthermore, most direct cooling solutions do not consider the buffering, shock absorption, and deformation adaptation requirements of the battery cells, making it difficult to simultaneously meet the comprehensive requirements of high heat dissipation efficiency, high sealing safety, and high structural compatibility.

[0005] Therefore, a solution is proposed. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a permeable liquid-cooled battery heat dissipation system with self-sealing function, solving the problems mentioned in the background section.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a permeable liquid-cooled battery heat dissipation system with self-sealing function, comprising a permeable layer, a sealing layer, and a coolant circulation system; the permeable layer is an open-cell foamed rubber layer directly attached to the surface of the battery cell, the open-cell foamed rubber layer having three-dimensional interconnected channels inside, the three-dimensional interconnected channels forming microchannels for coolant permeation and flow; the sealing layer is a closed-cell foamed rubber layer tightly wrapped around the outside of the permeable layer, the closed-cell foamed rubber layer being a completely water-impermeable and air-impermeable elastic sealing structure; the coolant circulation system is connected to the microchannels of the permeable layer through pipelines to achieve heat exchange of coolant circulation within the microchannels.

[0008] Preferably, the permeation layer is a hydrophilic open-cell silicone rubber, and the sealing layer is a closed-cell ethylene propylene rubber; the permeation layer and the sealing layer are integrally pressed together by hot vulcanization to form a double-layer composite structure, with no gaps, no delamination, and no leakage channels between the two layers.

[0009] Preferably, the three-dimensional interconnected channels inside the permeation layer are a continuous and interconnected microporous network. The coolant flows through the microporous network in a permeation manner and comes into direct contact with the surface of the battery cell, achieving zero-distance heat exchange and eliminating the contact thermal resistance of traditional liquid cooling structures.

[0010] Preferably, the sealing layer is a self-sealing elastomer structure that can generate adaptive elastic deformation under the action of coolant circulation pressure, always maintaining a fully enclosed and sealed state of the permeation layer, which can prevent coolant from leaking outward from the microchannel, forming an integrated self-sealing protection without additional sealing rings.

[0011] Preferably, the edge region of the permeation layer is provided with a fluid distribution area, which includes an inlet distribution chamber and an outlet distribution chamber; the inlet distribution chamber is connected to the inlet pipe of the coolant circulation system, and the outlet distribution chamber is connected to the outlet pipe of the coolant circulation system, so as to realize the uniform inflow and outflow of coolant into and out of the microchannels of the permeation layer.

[0012] Preferably, the fluid distribution zone is a flow equalization and pressure stabilization structure, which can reduce the flow resistance of coolant when entering the microchannel, so that the coolant is evenly distributed throughout the permeation layer and avoid uneven heat exchange caused by excessively fast or slow local flow rates.

[0013] Preferably, the permeation layer and the sealing layer are a flexible buffer structure that can deform synchronously with the thermal expansion and contraction during the charging and discharging process of the battery cell. It does not require rigid fasteners such as bolts and clips and can adapt to the surface bonding requirements of soft-pack battery cells and square battery cells.

[0014] Preferably, the coolant is an aqueous solution of ethylene glycol. The coolant flows in a laminar or low-turbulent state within the three-dimensional interconnected channels of the permeation layer, efficiently absorbing heat from the battery cell under low flow resistance conditions, and carrying the heat away through a circulation system.

[0015] Preferably, the coolant is an aqueous solution of ethylene glycol. The coolant flows in a laminar or low-turbulent state within the three-dimensional interconnected channels of the permeation layer, efficiently absorbing heat from the battery cell under low flow resistance conditions, and carrying the heat away through a circulation system.

[0016] Preferably, the thickness of the sealing layer is greater than the thickness of the permeation layer. A mechanical protective layer is formed on the outside of the sealing layer to resist external extrusion and vibration impact, while an anti-corrosion isolation layer is formed on the inside to prevent the coolant from directly contacting the battery cell terminals and the outer casing.

[0017] This invention provides a permeation-type liquid-cooled battery heat dissipation system with self-sealing function. It has the following beneficial effects:

[0018] 1. This invention uses the natural three-dimensional interconnected channels of open-cell foamed rubber as microchannels for coolant, allowing the coolant to directly permeate and flow inside the rubber in close contact with the battery cell. This achieves direct heat exchange between the coolant and the battery cell surface at zero distance, eliminating the contact thermal resistance caused by indirect heat exchange through thermal pads and metal pipes in traditional liquid cooling plates. This significantly improves heat exchange efficiency and can quickly remove the heat generated by the battery cell during operation, ensuring stable operation of the battery cell within a suitable temperature range.

[0019] 2. This invention uses a closed-cell foamed rubber layer to fully enclose and seal the permeation layer, forming an integrally molded self-sealing structure. It eliminates the need for additional metal flow channels, sealing rings, and complex sealing components, thus structurally preventing the risk of coolant leakage and cell corrosion. At the same time, the overall structure is simplified, the weight is reduced, and the assembly process is reduced, effectively reducing production and usage costs, and combining high safety and economy.

[0020] 3. The present invention is made of flexible foamed rubber material, which has good elasticity and deformation adaptability. It can fit tightly to the surface of the battery cell and adapt to the thermal expansion and contraction during the charging and discharging process of the battery cell. It can fit stably without rigid fasteners. At the same time, it also has the functions of buffering and shock absorption, which can alleviate the mechanical stress of the battery cell under vibration and impact conditions, extend the service life of the battery cell, and improve the overall reliability and durability of the battery system. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention. Detailed Implementation

[0022] The technical solutions in 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.

[0023] Please see the appendix Figure 1 This invention provides a self-sealing permeable liquid-cooled battery heat dissipation system, which is an integral flexible composite rubber structure, mainly comprising three parts: a permeable layer, a sealing layer, and a coolant circulation system. The permeable layer uses open-cell foamed rubber, with internal three-dimensional interconnected channels forming coolant microchannels, directly adhering to the battery cell surface for zero-distance heat exchange. The sealing layer uses closed-cell foamed rubber, completely encasing the permeable layer to form a self-sealing structure without sealing rings or metal channels, fundamentally preventing coolant leakage. The coolant circulation system provides stable and controllable coolant circulation power to the permeable layer, achieving continuous heat dissipation. The following specific embodiments provide a complete, clear, and detailed description of the technical solution of this invention.

[0024] Example 1

[0025] This embodiment is applicable to single-sided / double-sided bonding heat dissipation of soft-pack lithium-ion cells, and is the most basic and typical implementation method.

[0026] 1. Material selection and structural parameters

[0027] The permeation layer is made of hydrophilic open-cell silicone rubber with a porosity controlled at 65%–80%, forming a continuous, interconnected three-dimensional microporous network with a preferred pore size of 80μm–300μm. This ensures low-resistance flow of coolant within the micropores while maintaining structural strength and bonding stability. The sealing layer is made of highly elastic closed-cell EPDM rubber with a closed-cell rate ≥99%. It is completely impermeable to water and air, resistant to coolant corrosion, and resistant to high and low temperature aging. It can withstand system operating pressures of 0.1MPa–0.8MPa without cracking or leaking during long-term cycling. The preferred thickness of the permeation layer is 1mm–3mm, and the preferred thickness of the sealing layer is 0.5mm–2mm, with the overall total thickness controlled at 1.5mm–5mm to meet lightweight and thin design requirements.

[0028] 2. Integrated molding process

[0029] The permeation layer and the sealing layer are integrally molded using a hot vulcanization pressing process.

[0030] The hydrophilic open-cell silicone rubber semi-finished product and the closed-cell EPDM rubber semi-finished product are stacked according to the inner and outer layer structure.

[0031] Place it into the molding mold, control the temperature at 155℃–175℃, the mold closing pressure at 8MPa–12MPa, and hold the temperature and pressure for 15min–25min.

[0032] After vulcanization, the material is naturally cooled and demolded, forming a double-layer composite structure without interface gaps, delamination, or leakage channels.

[0033] The sealing layer completely encloses the permeable layer, with fluid distribution interfaces reserved only at one or both ends of the permeable layer, while the rest of the area is completely sealed.

[0034] 3. Fluid distribution and flow channel interface structure

[0035] A fluid distribution zone is set at the edge of the permeation layer, divided into a first fluid distribution zone (inlet end) and a second fluid distribution zone (outlet end). Multiple flow-equalizing channels are set within the fluid distribution zone, evenly distributed along the width direction, allowing the coolant to quickly fill the entire heat exchange area after entering the permeation layer, avoiding flow dead zones, insufficient local flow, or uneven heat exchange. Both the inlet and outlet ends are integrally formed with quick-connect mounting bases. The interfaces feature a conical sealing surface design, forming an interference fit seal with the inlet and outlet pipes of the coolant circulation system, eliminating the need for additional sealing rings, sealant, or clamps, achieving self-sealing of the interface.

[0036] 4. Coolant selection and operating parameters

[0037] The coolant is an ethylene glycol-water mixture with a volume ratio of ethylene glycol:deionized water of 40:60 to 60:40. It has a freezing point ≤ -35℃ and a boiling point ≥ 105℃, making it suitable for a wide temperature range of -40℃ to 110℃, accommodating both low-temperature preheating and high-temperature heat dissipation requirements. The system operating pressure is controlled between 0.2MPa and 0.5MPa, and the coolant flow rate is adjustable according to the cell's heat dissipation needs, achieving efficient heat exchange even under low flow conditions.

[0038] 5. Assembly method and working process

[0039] The heat dissipation system described in this embodiment is tightly attached to the main heating surface of the soft-pack battery cell using a planar or semi-enclosed method. The elasticity and flexibility of the rubber itself achieve a gapless fit, eliminating the need for thermally conductive gel, thermal pads, or other interface materials. During operation, the coolant, driven by a circulating pump, enters the first fluid distribution zone through the inlet pipe and diffuses evenly into the three-dimensional interconnected micropores of the permeation layer. It flows along the entire surface of the battery cell in a permeation flow form, directly exchanging heat with the cell and rapidly absorbing heat. After absorbing heat, the coolant flows through the second fluid distribution zone into the outlet pipe, returning to the external radiator / heat exchanger for cooling, before re-entering the circulation, achieving continuous closed-loop heat dissipation. During this process, the outer closed-pore sealing layer undergoes adaptive elastic expansion under internal hydraulic pressure, maintaining a fully enclosed seal on the permeation layer. Even with internal pressure fluctuations, temperature changes, or mechanical vibrations, coolant leakage or overflow will not occur, achieving permanent self-sealing.

[0040] 6. Adaptability and protection functions

[0041] The overall structure is a flexible elastomer that deforms synchronously with the thermal expansion and contraction of the battery cells during charging and discharging, maintaining a tight fit without warping, gaps, or detachment, eliminating the need for rigid fasteners such as bolts, brackets, and clips. Simultaneously, the closed-cell sealing layer combines buffering, shock absorption, impact resistance, and insulation protection functions, effectively absorbing vibrations and shocks from vehicle operation or energy storage system operation, reducing mechanical stress on the battery cells, preventing wear and crush damage, and improving cell safety and cycle life.

[0042] Example 2

[0043] The difference between this embodiment and Embodiment 1 is that the structure of the square aluminum-cased lithium-ion cell is optimized to improve the adaptability and sealing reliability of the rigid casing.

[0044] Material optimization: The permeation layer uses high-toughness open-cell nitrile rubber, and the sealing layer uses oil-resistant closed-cell fluororubber, further improving the overall resistance to electrolyte, coolant, and aging.

[0045] Structural optimization: The internal channels of the permeation layer adopt a gradient pore size design, with smaller pore size (50μm–150μm) on the side closer to the battery cell to improve heat transfer uniformity; and larger pore size (150μm–400μm) on the side closer to the sealing layer to reduce flow resistance.

[0046] Optimized shape: The outer surface of the sealing layer is equipped with positioning bosses, anti-slip textures and limiting slots to facilitate precise positioning within the battery module and prevent slippage or misalignment during use.

[0047] Enhanced sealing: A thickened sealing edge is added to the outside of the fluid distribution area to increase the sealing strength of the interface area, which can withstand higher system pressure and is suitable for high-power, high-flow heat dissipation scenarios.

[0048] Tests showed that the heat exchange efficiency of the heat dissipation system in this embodiment is more than 55% higher than that of traditional metal liquid cooling plates. After 1,500 hours of pressure cycling and high and low temperature shock tests, there were no leaks, cracks, or aging phenomena, and the maximum temperature difference of the battery was controlled within 3°C.

[0049] Example 3 This example is a module-level application, which integrates multiple heat dissipation units described in Example 1 or Example 2 in series / parallel to form a large-scale liquid cooling heat dissipation system suitable for power battery packs and energy storage battery clusters.

[0050] Integration method: The liquid inlet distribution areas of multiple heat dissipation units are connected to the main liquid inlet manifold, and the liquid outlet distribution areas are connected to the main liquid outlet manifold. The manifold adopts a flexible rubber tube or a lightweight plastic tube and is integrally sealed with the heat dissipation unit.

[0051] Flow equalization control: A flow equalizer is installed in the main inlet pipe to ensure that the coolant flow rate into each heat dissipation unit is consistent, so that the temperature of each cell in the module is uniform and avoids inconsistent cell performance degradation due to excessive temperature difference.

[0052] System Functions: The overall system simultaneously achieves five major functions: efficient heat dissipation, integrated self-sealing, flexible buffering, electrical insulation, and shock resistance, completely replacing the traditional multi-component combination structure of metal liquid cooling plates, thermal pads, sealing rings, and fixed brackets.

[0053] Applicable scenarios: It can be widely used in high-power battery systems such as power battery packs for new energy vehicles, home energy storage, industrial and commercial energy storage power stations, electric ships, and power supplies for construction machinery, which greatly simplifies the structure of thermal management systems, reduces weight and cost, and improves system reliability and safety.

[0054] Example 4 (Integrated Implementation of Low-Temperature Preheating and Temperature Control)

[0055] This embodiment adds a bidirectional temperature control function to the existing embodiment 1, achieving integrated high-temperature heat dissipation and low-temperature preheating. When the battery cell is in a low-temperature environment (<0℃), the coolant circulation system switches to preheating mode. An external heater heats the coolant to 25℃–40℃, and the hot coolant circulates within the micropores of the permeation layer, uniformly and rapidly preheating the battery cell through zero-distance contact, allowing the cell to quickly reach its optimal operating temperature range. Once the battery cell temperature rises to the operating range, the system automatically switches to heat dissipation mode, achieving automatic switching between high-temperature heat dissipation and low-temperature preheating. The sealing layer always remains self-sealing, ensuring no leakage, corrosion, or short-circuit risk during both preheating and heat dissipation processes, further expanding the applicability of the battery system in cold regions.

[0056] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the scope of the present invention. Any equivalent substitutions, parameter adjustments, material substitutions, or simple structural modifications made based on the technical solutions and concepts of the present invention within the scope of the technology disclosed in the present invention should be covered within the protection scope of the present invention.

Claims

1. A permeation-type liquid-cooled battery heat dissipation system with self-sealing function, characterized in that, The system includes a permeation layer, a sealing layer, and a coolant circulation system. The permeation layer is an open-cell foamed rubber layer that is directly bonded to the surface of the battery cell. The open-cell foamed rubber layer has three-dimensional interconnected channels inside, which form microchannels for coolant permeation and flow. The sealing layer is a closed-cell foamed rubber layer that is tightly wrapped around the outside of the permeation layer. The closed-cell foamed rubber layer is an elastic sealing structure that is completely impermeable to water and air. The coolant circulation system is connected to the microchannels of the permeation layer through pipelines to achieve heat exchange of coolant circulation within the microchannels.

2. The heat dissipation system according to claim 1, characterized in that, The permeation layer is a hydrophilic open-cell silicone rubber, and the sealing layer is a closed-cell ethylene propylene rubber. The permeation layer and the sealing layer are integrally pressed together by hot vulcanization to form a double-layer composite structure with no gaps, no delamination, and no leakage channels between the two layers.

3. The heat dissipation system according to claim 1, characterized in that, The three-dimensional interconnected channels inside the permeation layer form a continuous network of micropores. The coolant flows through the micropore network in a permeation manner and comes into direct contact with the surface of the battery cell, achieving zero-distance heat exchange and eliminating the contact thermal resistance of traditional liquid cooling structures.

4. The heat dissipation system according to claim 1, characterized in that, The sealing layer is a self-sealing elastomer structure that can generate adaptive elastic deformation under the action of coolant circulation pressure, always maintaining a fully enclosed and sealed state of the permeation layer, which can prevent coolant from leaking outward from the microchannel, forming an integrated self-sealing protection without additional sealing rings.

5. The heat dissipation system according to claim 1, characterized in that, The edge region of the permeation layer is provided with a fluid distribution area, which includes an inlet distribution chamber and an outlet distribution chamber. The inlet distribution chamber is connected to the inlet pipe of the coolant circulation system, and the outlet distribution chamber is connected to the outlet pipe of the coolant circulation system, so as to realize the uniform inflow and outflow of coolant into and out of the microchannels of the permeation layer.

6. The heat dissipation system according to claim 5, characterized in that, The fluid distribution zone is a flow equalization and pressure stabilization structure, which can reduce the flow resistance when the coolant enters the microchannel, so that the coolant is evenly distributed throughout the permeation layer and avoids uneven heat exchange caused by excessively fast or slow local flow rates.

7. The heat dissipation system according to claim 1, characterized in that, The permeation layer and sealing layer are a flexible buffer structure that can deform synchronously with the thermal expansion and contraction during the charging and discharging process of the battery cell. It does not require rigid fasteners such as bolts and clips and can adapt to the surface bonding requirements of soft-pack battery cells and square battery cells.

8. The heat dissipation system according to claim 1, characterized in that, The coolant is an aqueous solution of ethylene glycol. The coolant flows in a laminar or low-turbulent state within the three-dimensional interconnected channels of the permeation layer, efficiently absorbing heat from the battery cell under low flow resistance conditions, and carrying the heat out through the circulation system.

9. The heat dissipation system according to claim 1, wherein the thickness of the sealing layer is greater than the thickness of the permeation layer, a mechanical protective layer is formed on the outer side of the sealing layer to resist external extrusion and vibration impact, and an anti-corrosion isolation layer is formed on the inner side to prevent the coolant from directly contacting the battery cell terminals and the outer casing.

Images