Liquid cooling plate system capable of delaying thermal diffusion and electric equipment

Abstract

The invention relates to the technical field of battery safety, in particular to a liquid cooling plate system capable of delaying thermal diffusion. The battery comprises a plurality of battery cells, a heat insulation pad, a liquid cooling plate and a phase change material layer, the plurality of battery cells are arranged in parallel; the heat insulation pad is arranged between two adjacent battery cells; the liquid cooling plate is arranged at the bottom of the battery cell; the phase change material layer is arranged between the battery cell and the liquid cooling plate; wherein the phase change material layer comprises a phase change component, and the phase change component has a phase change temperature; when the temperature is lower than the phase change temperature, the phase change component is kept in a solid state, and an efficient heat conduction path from the battery cell to the liquid cooling plate is established; upon reaching or exceeding the phase change temperature, the phase change component is at least partially phase-changed, thereby significantly increasing the thermal resistance, deactivating the efficient thermal conduction path. Through the combination of the phase change material and the liquid cooling plate, the temperature control requirement during normal operation of the battery cell can be met, the thermal resistance can be intelligently increased during the thermal runaway period, and thermal diffusion is effectively prevented.

Description

Technical Field

[0001] This invention relates to the field of battery safety technology, specifically to a liquid cooling plate system for delaying heat diffusion and related electrical equipment. Background Technology

[0002] While the energy released by thermal runaway in a single battery is limited, the consequences of thermal runaway in an energy storage power station composed of tens of thousands of batteries are incalculable. The high-density arrangement of batteries in large-scale energy storage systems makes it highly susceptible to triggering a chain reaction once thermal runaway occurs, leading to fires or even explosions of the entire storage container, posing an extreme threat to life and property. Therefore, effectively preventing the massive heat generated by a single cell from spreading to other cells when thermal runaway is triggered has become a pressing challenge in the field of battery safety technology.

[0003] Existing technological solutions face a fundamental contradiction. First, in energy storage systems, most cooling systems rely on bottom liquid cooling of the battery cell. The operating temperature of the battery cell needs to be controlled within a reasonable range, which necessitates maintaining high thermal conductivity between the battery cell and the bottom liquid cooling plate, i.e., maintaining low contact thermal resistance. Second, when a battery cell experiences thermal runaway, it generates a large amount of heat accumulation, which naturally propagates along the path of least thermal resistance. Furthermore, considering the structural characteristics of the battery cell itself, mainstream cells are composed of positive and negative electrodes, a separator, and an electrolyte wound or stacked. This structural characteristic determines that the thermal resistance is high in the thickness direction and low in the vertical direction.

[0004] This contradiction manifests itself in two ways: to keep the battery cell operating within a reasonable temperature range, a low thermal resistance at the bottom is necessary. However, this makes it easier for the thermally runaway cell to transfer heat to adjacent cells through the bottom liquid cooling plate, potentially causing catastrophic thermal diffusion. Conversely, increasing the bottom thermal resistance for safety, while effectively suppressing the spread of thermal runaway, severely reduces heat exchange efficiency, making it difficult to control the cell's operating temperature within a reasonable range. Current technology cannot simultaneously meet these two drastically different requirements: efficient heat dissipation during normal operation and effective isolation during thermal runaway.

[0005] It is important to note that the direction of heat propagation has a significant impact on thermal runaway behavior. During normal operation, the high thermal conductivity in the vertical direction is beneficial for efficient heat dissipation of the battery, which is positive. However, when thermal runaway occurs, if heat propagates along the thickness of the cell, the thermal runaway will occur layer by layer due to the relatively high thermal resistance between the multilayer materials, thus slowing down the overall thermal diffusion process. On the other hand, if heat propagates in the vertical direction (i.e., perpendicular to the electrode direction), it will simultaneously heat all layered regions of the cell, easily triggering thermal runaway in all layers at the same time, significantly accelerating the thermal propagation process. Therefore, its harm is far greater than that of heat propagation in the thickness direction.

[0006] In summary, there is an urgent need for a liquid cooling plate system and electrical equipment that can delay heat diffusion in order to solve the above problems. Summary of the Invention

[0007] This invention addresses the technical problems existing in the prior art by providing a liquid cooling plate system and electrical equipment that delays heat diffusion. By combining phase change materials with liquid cooling plates, it can not only meet the temperature control requirements during normal operation of the battery cell, but also intelligently increase the thermal resistance during thermal runaway, effectively preventing heat diffusion and providing reliable safety assurance for large-scale energy storage systems.

[0008] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A liquid-cooled plate system for delaying heat diffusion includes: multiple battery cells, a heat insulation pad, a liquid-cooled plate, and a phase change material layer; Multiple battery cells are arranged side by side; The heat insulation pad is disposed between two adjacent battery cells; The liquid cooling plate is disposed at the bottom of the battery cell; The phase change material layer is disposed between the battery cell and the liquid cooling plate; The phase change material layer contains a phase change component with a phase change temperature. In a first temperature range below the phase change temperature, the phase change component remains solid, establishing an efficient heat conduction path from the battery cell to the liquid cooling plate. In a second temperature range that reaches or exceeds the phase change temperature, the phase change component undergoes at least a partial phase change, altering its physical state and significantly increasing thermal resistance, thereby causing the efficient heat conduction path to fail.

[0009] Based on the above technical solution, the present invention can be further improved as follows.

[0010] Furthermore, the plurality of battery cells are arranged side by side on the same liquid cooling plate; at least one boss is provided in the area of ​​the liquid cooling plate facing each battery cell.

[0011] Furthermore, each of the battery cells has multiple discrete protrusions on its underside, which are distributed at the mechanical stress points corresponding to the bottom of the battery cell.

[0012] Furthermore, the mechanical stress points include the four corners and the central area at the bottom of the battery cell.

[0013] Furthermore, the phase change material layer fills the gap between the liquid cooling plate and the battery cell, and covers the side of the boss.

[0014] Furthermore, the phase transition temperature of the phase transition component is selected to be between the battery's maximum normal operating temperature and the thermal runaway initiation temperature.

[0015] Furthermore, the two sides of the phase change material layer are in direct contact with and fixedly connected to the bottom of the battery cell and the upper surface of the liquid cooling plate, respectively.

[0016] Furthermore, the liquid cooling plate has at least one boss on the side facing the battery cell, and the top of the boss is in direct contact with the bottom of the battery cell.

[0017] The present invention also provides an electrical device, including the heat diffusion delay liquid cooling plate system as described above.

[0018] The beneficial effects of this invention are: This embodiment utilizes the abrupt temperature-dependent thermal properties of phase change materials to construct an adaptive thermal management path between the battery cell and the liquid cooling plate. In the low-temperature region, this path exhibits low thermal resistance, achieving efficient heat dissipation; in the high-temperature region, the path automatically switches to high thermal resistance, achieving thermal blocking. This embodiment relies on the material's own physical changes to achieve functional switching, thus exhibiting extremely high reliability and response speed. Furthermore, by combining it with a liquid cooling plate structure with protrusions and thermal insulation pads between the battery cells, the system not only demonstrates excellent thermal safety management but also maintains mechanical strength and structural compactness. Therefore, this embodiment provides a simple, reliable, efficient, and easily integrated thermal runaway control solution for high-energy-density battery systems, especially large-scale energy storage systems. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the exploded structure of the heat-delaying liquid cooling plate system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the heat-delaying liquid cooling plate system according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the liquid cooling plate according to an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the principle of the delayed thermal diffusion liquid cooling plate system for actively suppressing thermal runaway as described in an embodiment of the present invention. Figure 5 This is a simulation comparison of thermal runaway between the delayed heat diffusion liquid cooling plate system described in this embodiment of the invention and a comparative liquid cooling plate system.

[0020] The attached diagram lists the components represented by each number as follows: 1-Battery cell, 2-Insulation pad, 3-Phase change material layer, 4-Liquid cooling plate, 41-Boss. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0023] In the description of this application, the term "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0024] Example This embodiment provides a liquid-cooled plate system that delays heat diffusion, such as Figure 1-2 As shown, it includes: multiple battery cells 1, heat insulation pads 2, liquid cooling plates 4, and a phase change material layer 3; Multiple battery cells 1 are arranged side by side; The heat insulation pad 2 is disposed between two adjacent battery cells 1; The liquid cooling plate 4 is disposed at the bottom of the battery cell 1; The phase change material layer 3 is disposed between the battery cell 1 and the liquid cooling plate 4; The phase change material layer 3 contains a phase change component with a phase change temperature. In a first temperature range below the phase change temperature, the phase change component remains solid, establishing an efficient heat conduction path from the battery cell 1 to the liquid cooling plate 4. In a second temperature range that reaches or exceeds the phase change temperature, the phase change component undergoes at least a partial phase change, altering its physical state and significantly increasing thermal resistance, thereby causing the efficient heat conduction path to fail.

[0025] This embodiment includes multiple square lithium-ion cells 1 arranged side by side, with heat insulation pads 2 installed between the cells 1. An aluminum liquid cooling plate 4 is arranged at the bottom of all the cells 1. A phase change material layer 3 is filled between the liquid cooling plate 4 and the bottom of each cell 1. This phase change material has a phase change temperature of 180°C. Figure 4 As shown, the material is solid at temperatures below 180°C and has good thermal conductivity and adhesion, meeting the requirements for heat exchange and structural strength, and efficiently conducting the heat generated by the battery cell 1 to the liquid cooling plate 4. When the local temperature of the battery cell 1 exceeds 180°C, the material melts or evaporates, and the thermal conductivity drops sharply, effectively blocking the heat transfer to the liquid cooling plate 4.

[0026] It should be noted that the phase change material layer 3 is a polymer-based thermally conductive phase change material, which is made of an epoxy resin matrix and thermally conductive fillers.

[0027] The epoxy resin matrix is ​​made of low-melting-point solid epoxy resin, which begins to melt and gradually loses structural strength at a temperature of 180°C, undergoing a phase transition. This temperature is higher than the normal operating temperature of the battery (typically ≤60°C), but lower than the initiation temperature of thermal runaway (typically >200°C), thus ensuring that it remains solid and structurally stable during normal battery operation, while responding rapidly in the early stages of thermal runaway.

[0028] The thermally conductive filler is aluminum nitride (AlN) powder. The highly thermally conductive aluminum nitride filler forms an effective heat conduction path, thereby ensuring the overall high thermal conductivity.

[0029] During normal charging and discharging of the battery module, the heat generated by cell 1 is dissipated through the following path: from the bottom of cell 1, through phase change material layer 3 (high thermal conductivity solid), through liquid cooling plate 4, to the coolant. At this time, phase change material layer 3 acts as a highly efficient thermally conductive medium, ensuring the system's heat dissipation requirements. When one of the cells 1 experiences an internal short circuit or other abnormal situation and progresses to thermal runaway, its temperature rises sharply. When the temperature of the bottom interface of this cell 1 reaches and exceeds the melting temperature of phase change material layer 3 (e.g., 180°C), the localized phase change material in contact with it begins to melt into a liquid state or evaporate. This process leads to: Thermal connection failure: Liquid materials cannot maintain the original tight contact, and the interfacial thermal resistance increases sharply.

[0030] Disruption of the heat conduction path: The molten resin disrupts the pre-built solid thermally conductive filler network, resulting in a significant decrease in the overall thermal conductivity of the material.

[0031] Structural support changes: The material loses its adhesiveness, which may create a tiny gap between cell 1 and liquid cooling plate 4.

[0032] These changes work together to effectively cut off the originally efficient axial heat conduction path from the battery cell 1 to the liquid cooling plate 4. The large amount of heat generated by the thermal runaway battery cell 1 is difficult to diffuse through the bottom, and is thus greatly confined inside the battery cell 1 or can only be slowly transferred through lateral paths with high thermal resistance (such as the heat insulation pad 2 between the battery cells 1), ultimately achieving the purpose of delaying or even preventing heat diffusion.

[0033] In a preferred embodiment, such as Figure 3 As shown, the plurality of battery cells 1 are arranged side by side on the same liquid cooling plate 4; at least one protrusion 41 is provided in the area of ​​the liquid cooling plate 4 facing each of the battery cells 1.

[0034] Specifically, each of the battery cells 1 has multiple discrete protrusions 41 on its underside, and these protrusions 41 are distributed at the mechanical stress points corresponding to the bottom of the battery cell 1.

[0035] Specifically, the mechanical stress points include the four corners and the middle area of ​​the bottom of the battery cell 1.

[0036] Specifically, the phase change material layer 3 fills the gap between the liquid cooling plate 4 and the battery cell 1, and covers the side of the boss 41.

[0037] In this embodiment, the liquid cooling plate 4 is a single extruded aluminum plate, the size of which covers the bottom projected area of ​​all parallel battery cells 1. On the upper surface of the liquid cooling plate 4, five cylindrical protrusions 41 are provided for the installation position of each battery cell 1, corresponding to the four corner points and the geometric center point of the bottom of the battery cell 1, respectively. These points are the main stress points where the battery cell 1 deforms during charging and discharging. The protrusions 41 are arranged at these five points to provide optimal support and heat conduction. The phase change material layer 3 fully fills all the gaps between the liquid cooling plate 4 and the battery cell 1 and covers the sides of the protrusions 41, thereby maximizing the thermal contact area and improving heat dissipation performance under normal conditions, and completely destroying the heat path through the change of material state when the phase change occurs, achieving efficient heat blocking.

[0038] This embodiment integrates multiple battery cells 1 onto the same liquid cooling plate 4, and distributes multiple protrusions 41 at the mechanical stress points (including the four corners and the center) in the corresponding area of ​​each battery cell 1, thus constructing a structural foundation that combines mechanical stability and efficient thermal management capabilities. This layout not only significantly improves the uniformity of support of the liquid cooling plate 4 for the battery cells 1 and effectively disperses mechanical stress, avoiding local deformation, but also ensures that the phase change material layer 3 can form a more sufficient and reliable thermal contact interface with the battery cells 1 and the liquid cooling plate 4. This optimizes the heat dissipation path when the battery is working normally, and can still maintain the necessary structural integrity when thermal runaway occurs, providing a stable environment for the adaptive change of thermal resistance.

[0039] In a preferred embodiment, the phase transition temperature of the phase transition component is selected to be between the battery's maximum normal operating temperature and the thermal runaway initiation temperature. By strictly setting the phase transition temperature between the battery's normal operating limit and the thermal runaway initiation temperature, it is ensured that the material layer activates its thermal blocking function only when thermal runaway actually occurs, while maintaining efficient thermal conductivity throughout the battery's normal operating period, thus achieving an intelligent and reliable thermal response.

[0040] In a preferred embodiment, the two sides of the phase change material layer 3 are in direct contact with and fixedly connected to the bottom of the battery cell 1 and the upper surface of the liquid cooling plate 4, respectively.

[0041] In this embodiment, the phase change material layer 3 is viscous at room temperature, and its upper and lower surfaces are firmly bonded to the bottom of the aluminum shell of the battery cell 1 and the upper surface of the liquid cooling plate 4 respectively by thermally conductive adhesive, ensuring extremely low interfacial thermal resistance and good structural integrity.

[0042] In a preferred embodiment, the liquid cooling plate 4 is provided with at least one boss 41 on the side facing the battery cell 1, and the top of the boss 41 is in direct contact with the bottom of the battery cell 1.

[0043] In this embodiment, the boss 41 and the liquid cooling plate 4 are integrally formed, with its top being a precision-machined plane that directly contacts the bottom of the battery cell 1, undertaking the main tasks of support and heat conduction. Phase change material is filled in the surrounding area of ​​the boss 41. By setting the boss 41 structure, direct mechanical support and a heat conduction path are provided for the battery cell 1. The top of the boss 41 contacts the battery cell 1, ensuring mechanical stability. Simultaneously, as part of the liquid cooling plate 4, it also forms an efficient heat dissipation channel and works in conjunction with the phase change material to manage heat transfer and blocking.

[0044] The present invention also provides an electrical device, including the heat diffusion delay liquid cooling plate system as described above.

[0045] This embodiment also provides an outdoor energy storage cabinet, which integrates a battery module including the aforementioned heat diffusion delay liquid cooling plate system. This liquid cooling plate system is connected to an external coolant circulation system via pipelines, jointly providing thermal management protection for the energy storage cabinet.

[0046] The specific assembly of this embodiment is as follows: The phase change material layer 3 described in this embodiment is cut to a size that matches the bottom of the battery cell 1. One side of it is pasted onto the upper surface of the liquid cooling plate 4, especially filling the area between the protrusions 41 of the liquid cooling plate 4. Subsequently, the battery cells 1 are pressed one by one onto the phase change material layer 3, ensuring that a tight contact is established between the bottom of the battery cell 1, the phase change material layer 3, and the top of the protrusions 41 of the liquid cooling plate 4.

[0047] The working process of this embodiment is as follows: The overall operation of the heat-delaying liquid cooling plate system described in this embodiment is based on the changes in the physical properties of the phase change material. Its working principle is to intelligently adjust the thermal resistance according to the temperature. During normal operation of the battery system, the heat generated by the cell 1 is transferred to the solid phase change material layer 3 through its bottom. Due to the good thermal conductivity of the solid phase change material, the heat is quickly directed to the liquid cooling plate 4 and finally carried away by the coolant flowing through the internal channels of the liquid cooling plate 4, thereby maintaining the temperature of the cell 1 within the optimal operating range.

[0048] like Figure 4 As shown, when the battery cell 1 is working, it will generate heat. A small part of the heat is transferred to the liquid cooling plate 4 through the boss 41, and most of the heat is transferred to the liquid cooling plate 4 through the phase change material layer 3.

[0049] When a battery cell 1 enters a thermal runaway process due to abuse conditions such as internal short circuit or overcharging, its temperature rises sharply. Once the bottom temperature of the battery cell 1 reaches or exceeds the preset phase change temperature of the phase change material (180°C), the phase change material layer 3 in contact with the battery cell 1 will undergo a phase change, typically melting from a solid to a liquid state or evaporating. The thermal conductivity of liquid phase materials is much lower than that of solid phases, and the melting or evaporation process of the material may be accompanied by volume changes and interface contact failure, resulting in a sharp increase in thermal resistance of several orders of magnitude in this local area. This is equivalent to automatically inserting a highly efficient thermal switch between the runaway battery cell 1 and the shared liquid cooling plate 4, which is in a closed state. Heat can no longer diffuse rapidly through the low thermal resistance bottom path, interrupting the path of heat transfer from the phase change material layer 3 to the liquid cooling plate 4, thus effectively confining it within the initially runaway battery cell 1, or allowing it to be slowly transferred through lateral paths with higher thermal resistance (such as the thermal insulation pad 2 between battery cells 1), thereby greatly slowing down the rate at which heat spreads to adjacent battery cells 1.

[0050] To facilitate understanding and visualization, a thermal runaway simulation experiment was conducted between the heat-delaying liquid cooling plate system described in this embodiment and a comparative liquid cooling plate system 4. The only difference between the comparative liquid cooling plate system 4 and the heat-delaying liquid cooling plate system described in this embodiment is that the comparative liquid cooling plate system 4 does not have a phase change material layer 3.

[0051] Simulates overcharge-triggered thermal runaway conditions. Figure 5 The two images above, from left to right, show the thermal runaway simulations of the liquid-cooled plate 4 system at 2000 seconds and 4000 seconds, respectively. Figure 5 The two figures below, from left to right, are simulation diagrams of thermal runaway of the delayed heat diffusion liquid cooling plate system described in this embodiment at 2000 seconds and 4000 seconds, respectively.

[0052] The results were obtained through thermal runaway simulation calculations, such as Figure 5As shown, the liquid cooling plate 4 system completely thermally ran away after 4000 seconds, while the heat diffusion delay liquid cooling plate system described in this embodiment only had one cell 1 thermally run away after 4000 seconds. Therefore, this embodiment can indeed effectively suppress heat diffusion.

[0053] While embodiments or examples of this disclosure have been described with reference to the accompanying drawings, it should be understood that the methods, systems, and devices described above are merely exemplary embodiments or examples, and the scope of the invention is not limited by these embodiments or examples, but only by the granted claims and their equivalents. Various elements in the embodiments or examples may be omitted or replaced by their equivalents. Furthermore, the steps may be performed in a different order than that described in this disclosure. Further, various elements in the embodiments or examples may be combined in various ways. Importantly, as the technology evolves, many elements described herein can be replaced by equivalents that appear after this disclosure.

Claims

1. A liquid-cooled plate system for delaying heat diffusion, characterized in that, include: Multiple battery cells, heat insulation pads, liquid cooling plates, and phase change material layers; Multiple battery cells are arranged side by side; The heat insulation pad is disposed between two adjacent battery cells; The liquid cooling plate is disposed at the bottom of the battery cell; The phase change material layer is disposed between the battery cell and the liquid cooling plate; The phase change material layer contains a phase change component with a phase change temperature. In a first temperature range below the phase change temperature, the phase change component remains solid, establishing an efficient heat conduction path from the battery cell to the liquid cooling plate. In a second temperature range that reaches or exceeds the phase change temperature, the phase change component undergoes at least a partial phase change, altering its physical state and significantly increasing thermal resistance, thereby causing the efficient heat conduction path to fail.

2. The heat-delaying liquid cooling plate system according to claim 1, characterized in that, The multiple battery cells are arranged side by side on the same liquid cooling plate; the liquid cooling plate has at least one protrusion in the area facing each battery cell.

3. The heat-delaying liquid cooling plate system according to claim 2, characterized in that, Each of the battery cells has multiple discrete protrusions on its underside, which are distributed at the mechanical stress points on the bottom of the corresponding battery cell.

4. The heat diffusion delay liquid cooling plate system according to claim 2, characterized in that, The mechanical stress points include the four corners and the central area at the bottom of the battery cell.

5. The heat-delaying liquid cooling plate system according to claim 4, characterized in that, The phase change material layer fills the gap between the liquid cooling plate and the battery cell, and covers the side of the boss.

6. The heat-delaying liquid cooling plate system according to claim 1, characterized in that, The phase transition temperature of the phase transition component is selected to be between the battery's highest normal operating temperature and the thermal runaway initiation temperature.

7. The heat-delaying liquid cooling plate system according to claim 1, characterized in that, The two sides of the phase change material layer are in direct contact with and fixedly connected to the bottom of the battery cell and the upper surface of the liquid cooling plate, respectively.

8. The heat diffusion delay liquid cooling plate system according to claim 1, characterized in that, The liquid cooling plate has at least one boss on the side facing the battery cell, and the top of the boss is in direct contact with the bottom of the battery cell.

9. An electrical appliance, characterized in that, Including the heat diffusion delay liquid cooling plate system as described in any one of claims 1-8.

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