Phase change liquid cooling plate, battery module and battery pack

Abstract

The utility model provides a kind of phase change liquid cooling plate, battery module and battery pack, it is related to liquid cooling plate technical field, comprising: cold plate body, the inner cavity of cold plate body is filled with coolant, at least one side panel of cold plate body is embedded with multiple plugs, the spray opening that is communicated with the inner cavity is opened on the plug, the first phase change material is filled in the spray opening.A beneficial effect is to meet the heat exchange demand of normal working condition, when the thermal runaway occurs in the battery cell, the temperature rapidly rises to the phase transition temperature of the first phase change material, the first phase change material rapidly changes from solid to liquid or gaseous state, and then the coolant in the inner cavity of the cold plate body is directly sprayed to the surface of the thermal runaway battery cell through the spray opening, realizing the mode switching from indirect heat exchange to direct spray heat exchange, effectively improving the heat exchange efficiency, and direct spray can accurately cool the thermal runaway battery cell, avoiding heat transfer to adjacent battery cells, effectively delaying or preventing the spread of thermal runaway.

Description

Technical Field

[0001] This utility model relates to the field of liquid cooling plate technology, and in particular to phase change liquid cooling plates, battery modules, and battery packs. Background Technology

[0002] In fields such as new energy vehicles and energy storage systems, the power battery pack, as a core energy supply component, directly determines the operating efficiency and safety of the entire equipment through its performance and safety stability. The performance and safety of the power battery pack are highly dependent on the operating temperature environment of the battery cells. When the cells are subjected to extreme high and low temperature conditions, their charge and discharge efficiency and cycle life will decrease significantly, and may even lead to serious safety accidents such as thermal runaway. Current power battery pack thermal management solutions integrate cold plate components within the overall battery pack structure. Through heat exchange between the cold plate and the cells, the heat generated by the cells during charging and discharging can be promptly removed. Simultaneously, in low-temperature environments, it can also work with the heating system to provide heat to the cells, ensuring that the cells remain within a suitable operating temperature range. Furthermore, when a thermal runaway accident occurs in the entire power battery pack, the cold plate system can activate the water circulation function, using the flow of coolant to achieve rapid cooling, thereby delaying or preventing the further spread of thermal runaway and buying valuable time for equipment safety protection.

[0003] Existing cold plates typically use thermally conductive adhesive to connect the cold plate and the cell at the bottom or large surface of the cell for heat exchange, ensuring the cell operates at its optimal temperature under high and low temperature conditions. From a heat exchange principle perspective, existing cold plates maintain structural integrity throughout the entire process; that is, the sealed cavity of the cold plate will not crack or open. Coolant circulates within the sealed cavity of the cold plate. When heat is transferred from the cell to the cold plate shell, the coolant inside the shell absorbs the heat and carries it away through the circulation system, thus cooling the cell. In this process, the coolant does not directly contact the cell; instead, heat transfer occurs through the cold plate shell as an intermediate medium, representing a typical indirect heat exchange method. However, in the event of a thermal runaway emergency in a power battery pack, the high heat generated by the cells needs to be quickly dissipated to prevent the heat from being transferred to adjacent cells and to suppress the spread of thermal runaway. However, due to the large thermal resistance caused by the indirect heat exchange between the coolant and the cells, the heat needs to pass through the thermally conductive adhesive between the cells and the cold plate, the cold plate material, and the heat transfer interface between the coolant and the cold plate in sequence. This series of steps results in a slow heat transfer speed, making it impossible to quickly dissipate the heat released by the cells that trigger thermal runaway in the first instance. Consequently, it is impossible to prevent the heat from being transferred to adjacent cells in large quantities, ultimately causing the thermal runaway phenomenon to continue to spread and failing to achieve an effective thermal runaway suppression effect, which seriously threatens the safety of the power battery pack.

[0004] To address the issue of low heat transfer rates in existing cold plate technology during thermal runaway, several other cooling solutions have emerged in the industry, such as immersion cooling and spray cooling. The immersion cooling solution involves completely submerging the battery cells in an insulating coolant, allowing heat exchange through direct contact between the coolant and the cells. While this solution offers high heat exchange efficiency, it requires a specially designed sealed cavity for the battery pack to hold the coolant. Additionally, it necessitates a series of auxiliary systems for coolant circulation, filtration, and cooling, resulting in an extremely complex cooling system structure. This not only increases the size and weight of the battery pack but also raises the system's manufacturing costs and maintenance complexity.

[0005] Spray cooling, on the other hand, uses nozzles to directly spray coolant onto the surface of the battery cells for heat exchange, also offering high heat exchange efficiency. However, this solution requires numerous nozzles, coolant pipelines, and coolant recovery devices within the battery pack. These components occupy a significant amount of internal space, reducing the cell density and consequently drastically decreasing the battery pack's energy density. In applications such as new energy vehicles, where high energy density is crucial, a decrease in energy density directly impacts key performance indicators like driving range. Therefore, spray cooling solutions are difficult to implement on a large scale in these scenarios.

[0006] Therefore, developing a new power battery pack cooling technology that can solve the above problems has significant practical importance and market value. Utility Model Content

[0007] To address the problems existing in the prior art, this utility model provides a phase change liquid cooling plate, including a cooling plate body, the inner cavity of the cooling plate body being filled with coolant, and a plurality of plugs being embedded on at least one side panel of the cooling plate body, the plugs having spray nozzles communicating with the inner cavity, the spray nozzles being filled with a first phase change material.

[0008] Preferably, the plug is funnel-shaped.

[0009] Preferably, there are multiple spray nozzles, and each spray nozzle is distributed in a shower-like pattern.

[0010] Preferably, at least one side of the cold plate body where the plug is embedded is provided with a phase change diaphragm.

[0011] Preferably, the phase change separator is made of a second phase change material, and the phase change temperature of the second phase change material is lower than that of the first phase change material.

[0012] Preferably, the cold plate body and the phase change separator are connected and fixed by a fixed frame.

[0013] Preferably, the thickness of the phase change separator is 1mm-3mm.

[0014] Preferably, the coolant is an insulating coolant.

[0015] This utility model also provides a battery module, including multiple battery cells, with the aforementioned phase change liquid cooling plate disposed between two adjacent battery cells.

[0016] This utility model also provides a battery pack, including the above-mentioned battery module.

[0017] The above technical solution has the following advantages or beneficial effects: 1) By embedding multiple plugs on at least one side panel of the cold plate body, and providing spray nozzles that communicate with the inner cavity on the plugs, and filling the spray nozzles with a first phase change material, the following can be achieved: During normal operation of the power battery pack, the first phase change material remains solid and tightly fills the spray nozzle of the plug, ensuring that the inner cavity of the cold plate body is in a closed state. The coolant circulates in the conventional indirect heat exchange mode to meet the heat exchange requirements under normal operating conditions. However, when the cell experiences thermal runaway and the temperature rises sharply to the phase change temperature of the first phase change material, the first phase change material quickly changes from solid to liquid or gas, losing its sealing effect on the spray nozzle. Then, the coolant in the inner cavity of the cold plate body is directly sprayed onto the surface of the thermal runaway cell through the spray nozzle under its own circulation pressure or thermal expansion pressure. This achieves a mode switch from indirect heat exchange to direct spray heat exchange, effectively improving heat exchange efficiency. Furthermore, direct spraying can precisely cool the thermal runaway cell, preventing heat transfer to adjacent cells and effectively delaying or preventing the spread of thermal runaway. 2) By integrating the plug and the first phase change material into the cold plate body panel, efficient heat exchange is provided, heat spread is suppressed, the structure is simple, and there is no need to occupy additional space inside the power battery pack to arrange components such as nozzles and pipes, which reduces manufacturing costs. At the same time, it reduces the maintenance needs of auxiliary systems such as sealing and filtration, reducing later operation and maintenance costs. In addition, since no additional components are required to occupy space, more area can be reserved inside the power battery pack for arranging cells, which is perfectly adapted to application scenarios with stringent requirements for high energy density, such as new energy vehicles. Attached Figure Description

[0018] Figure 1 A schematic diagram of the structure of a phase change liquid cooling plate is shown in a preferred embodiment of this utility model. Figure 2 This is a schematic diagram of the plug structure in a preferred embodiment of the present invention. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The present invention is not limited to this embodiment; other embodiments that conform to the spirit of the present invention may also fall within its scope.

[0020] In a preferred embodiment of this utility model, based on the above-mentioned problems existing in the prior art, a phase change liquid cooling plate is provided, such as... Figure 1 and Figure 2 As shown, the device includes a cold plate body 1, the inner cavity of which is filled with coolant, and a plurality of plugs 2 are embedded on at least one side panel of the cold plate body 1. Each plug 2 has a spray nozzle 3 that communicates with the inner cavity, and the spray nozzle 3 is filled with a first phase change material.

[0021] Specifically, in this embodiment, the aforementioned cold plate body 1 is preferably made of metal or composite material substrate, and the specific material is not limited. The cold plate body 1 is also provided with a liquid cooling inlet 8 and a liquid cooling outlet 9 for circulating coolant under normal operating conditions. The aforementioned first phase change material can be an inorganic phase change material with a phase change temperature approximately 20°C higher than the cell's thermal runaway self-generated heat temperature T1 and approximately 30°C~50°C lower than the cell's thermal runaway temperature T2, generally around 130°C. By setting a plug 2 and opening a spray nozzle 3 filled with the first phase change material on the plug 2, while ensuring the structural integrity of the cold plate body 1 during normal operation, the temperature-sensitive phase change characteristics of the first phase change material are utilized to achieve timely phase change dissolution and spraying of coolant under thermal runaway conditions.

[0022] More specifically, during normal operation of the power battery pack, the first phase change material remains solid and tightly fills the spray nozzle 3 of the plug 2, ensuring that the inner cavity of the cold plate body 1 is in a closed state, thus guaranteeing the structural integrity of the cold plate body 1 during normal operation. At this time, the coolant circulates according to the conventional indirect heat exchange mode, meeting the heat exchange requirements under normal operating conditions.

[0023] When a battery cell experiences thermal runaway and its temperature rises rapidly to the phase change temperature of the first phase change material, the material quickly transforms from a solid to a liquid or gaseous state, losing its sealing effect on the spray nozzle 3. At this point, the coolant inside the cold plate body 1, under its own circulation pressure or thermal expansion pressure, is directly sprayed onto the surface of the thermally runaway battery cell through the spray nozzle 3. This achieves a switch from indirect heat exchange to direct spray heat exchange, shortening the heat exchange path from the existing indirect path from the battery cell to the cold plate shell and then to the coolant to a direct path from the coolant to the battery cell surface. This significantly reduces thermal resistance and effectively improves the heat exchange rate. Simultaneously, direct spraying can precisely cool the thermally runaway battery cell, preventing heat transfer to adjacent cells and effectively delaying or preventing the spread of thermal runaway. This buys crucial time for the safety protection of the power battery pack and solves the problem of poor thermal runaway suppression effect of existing ordinary cold plates. Furthermore, compared to existing immersion cooling and spray cooling, this invention eliminates the need for additional independent sealed cavities, nozzle arrays, or recovery systems. It achieves both conventional indirect heat exchange and emergency spray heat exchange simply by integrating a plug 2 with the first phase change material embedded in the panel of the cold plate body 1. In other words, the cold plate body 1 functions as both a conventional cold plate and a spray device, eliminating the need for additional space within the battery pack for nozzles, pipes, and other components. This effectively reduces structural complexity, lowers manufacturing costs, and facilitates large-scale deployment. Simultaneously, the absence of additional components allows for more space within the battery pack to accommodate battery cells, significantly increasing cell density compared to existing spray solutions. This enhances the energy density of the battery pack, perfectly suited for applications requiring high energy density, such as new energy vehicles, and addresses the dual challenges of complex and costly immersion cooling and low energy density associated with spray cooling.

[0024] Furthermore, since no additional nozzles or pipes are required, the large surface of the cold plate body 1 can be tightly bonded to the surface of the battery cell under normal operating conditions, ensuring uniform contact pressure between the two. Additionally, when the battery cell temperature in some areas is slightly higher than in others, the first phase change material in those areas may not have fully undergone phase change, but may have softened locally, creating tiny gaps in the spray nozzles 3. Coolant can then seep out in small amounts through these gaps, providing a slight cooling effect to the locally high-temperature battery cells. This achieves precise localized cooling, improves temperature uniformity, and effectively solves the current problems of low heat exchange efficiency and poor temperature uniformity in large-area cooling systems.

[0025] In a preferred embodiment of this invention, the plug 2 is funnel-shaped.

[0026] Specifically, in this embodiment, at least one large side of the cold plate body 1 is provided with a phase change outlet 6 that matches the shape of the plug 2. The plug 2 is designed as a funnel, and the phase change outlet 6 and the plug 2 are interference-fitted. This causes the plug 2 to undergo radial elastic deformation due to the interference, tightly squeezing the inner wall of the phase change outlet 6 and forming a continuous radial clamping force. At the same time, the funnel-shaped conical structure expands the contact area of ​​the interference fit, so that the clamping force is evenly distributed across the entire conical surface, rather than concentrated in a local area. This effectively improves the pull-out resistance of the plug 2, thus ensuring that the plug 2 will not loosen or shift or experience increased gaps under long-term high-frequency vibration conditions of the power battery pack. Even in extreme vibration tests, it can still maintain a stable embedded state, providing a guarantee for the long-term structural stability of the cold plate system.

[0027] Furthermore, the interference fit between the funnel-shaped plug 2 and the phase change outlet 6 ensures a tight, gapless fit between the outer conical surface of the plug 2 and the inner conical surface of the phase change outlet 6. Even if the cold plate body 1 experiences slight thermal expansion and contraction due to temperature changes, the elastic deformation generated by the interference fit can compensate for the dimensional changes, maintaining a tight seal. The radial pressure generated by the interference fit significantly increases the coefficient of friction between the sealing surfaces, effectively preventing coolant penetration. This ensures that under normal operating conditions, the coolant inside the cold plate body 1 is absolutely sealed, preventing leakage that could lead to reduced heat exchange efficiency and coolant loss, and meeting the 1.2 MPa cold plate burst pressure requirement.

[0028] In a preferred embodiment of this utility model, there are multiple spray nozzles 3, and each spray nozzle 3 is distributed in a shower head pattern.

[0029] Specifically, in this embodiment, since the filling component of the phase change outlet 6 is not entirely composed of the first phase change material, but is composed of a spray nozzle 3 opened on the plug 2 and filled with the first phase change material, it ensures that the phase change outlet 6 opens when the whole package is thermally runaway. Through the shower-type spray structure, the coolant is divided and pressurized under the internal cavity pressure of the cold plate body 1, thereby significantly increasing the flow rate of the coolant when it passes through multiple small-diameter spray nozzles 3, thus providing high-speed fine stream coolant and improving heat exchange efficiency.

[0030] In addition, the number of phase change outlets 6 is designed to be at least 2 layers or more in the height direction of the large surface of the cell and at least 5 layers or more in the length direction of the cell, so as to achieve the maximum spray area and the highest heat exchange effect.

[0031] In a preferred embodiment of the present invention, a phase change diaphragm 4 is provided on at least one side of the cold plate body 1 where the plug 2 is embedded.

[0032] Specifically, in this embodiment, the phase change separator 4 is made of a second phase change material with a thickness of 1mm-3mm, and the phase change separator 4 should have two characteristics: 1) It has a certain degree of compressibility to ensure breathing space throughout the cell's life cycle. During long-term charge-discharge cycles, the battery cell experiences a "breathing" effect due to changes in the volume of its active materials. This means the active materials expand during charging and contract during discharging, causing variations in cell thickness. If there is no flexible buffer structure between the cold plate body 1 and the battery cell, rigid contact will restrict this "breathing," leading to active material shedding and a shortened cell lifespan. Therefore, in this embodiment, the phase change separator 4 is designed with a thickness of 1mm-3mm, providing sufficient compression margin to fully accommodate volume fluctuations throughout the battery cell's lifespan and prevent the cold plate body 1 from rigidly compressing the cell.

[0033] 2) The phase change temperature is around 100℃, which is higher than the cell's self-generated heat temperature T1 under thermal runaway, but lower than the cell's thermal runaway temperature T2, to ensure the structural integrity under normal operating conditions and the rapid dissipation of absorbed heat under thermal runaway conditions. At the same time, the phase change temperature of the phase change separator 4 should be lower than the phase change temperature of the first phase change material.

[0034] Because the phase change temperature of the phase change separator 4 is lower than that of the first phase change material, in the early stages of thermal runaway, when the cell temperature rises to around 100°C, the second phase change material of the phase change separator 4 is the first to trigger a phase change, transforming from a solid state to a liquid or gaseous state. During the phase change process, the phase change separator 4 absorbs a large amount of latent heat of phase change, which can quickly reduce the cell surface temperature and slow down the rate at which the temperature rises to T2. This provides a buffer time for the subsequent opening of the phase change outlet 6 and the spray heat exchange, preventing the cell temperature from precipitating to the thermal runaway threshold.

[0035] Furthermore, during the middle stage of thermal runaway, when the cell temperature continues to rise to the phase change temperature of the first phase change material at the phase change outlet 6, the first phase change material melts, the spray nozzle 3 opens, and the coolant is sprayed directly onto the cell surface through a shower-like spray, forming a thermal runaway stepped protection mechanism that first absorbs heat and buffers, provides spray space for coolant spraying, and then sprays to cool down, effectively improving the safety and reliability of thermal runaway protection for the power battery pack.

[0036] In a preferred embodiment of this utility model, the cold plate body 1 and the phase change separator 4 are connected and fixed by a fixing frame 5.

[0037] Specifically, in this embodiment, the fixing frame 5 preferably has grooves on both sides in the circumferential direction, and the liquid-cooled body 1 and the phase change separator 4 are respectively locked in the grooves to achieve fixation. In addition, the fixing frame 5 must have high temperature resistance and insulation properties to ensure that it can still provide stable support for the cold plate body 1 during the thermal runaway expansion of the battery cell. After the phase change separator 4 undergoes phase change and dissolution, there is a certain gap between the cold plate body 1 and the battery cell, providing spray space for the thermal runaway battery cell and avoiding direct contact between the cold plate body 1 and the surface of the battery cell, which would cause the spray nozzle 3 to be blocked, thus ensuring the spray heat dissipation effect.

[0038] In a preferred embodiment of this invention, the coolant is an insulating coolant, so that after the entire package is subjected to thermal runaway spray cooling, the coolant will not cause insulation problems for the entire package.

[0039] This utility model also provides a battery module, including multiple battery cells, with the aforementioned phase change liquid cooling plate disposed between two adjacent battery cells.

[0040] Specifically, such as Figure 1As shown, a phase change liquid cooling plate is provided between two adjacent battery cells 7. Preferably, phase change outlets 6 can be opened on both large surfaces of the cooling plate body 1, and plugs 2 can be embedded accordingly. Based on this, phase change spacers 4 are provided on both sides of the cooling plate body 1 and fixed to the cooling plate body 1 by corresponding fixing frames 5. This allows the phase change spacers 4 on both sides of the cooling plate body 1 to respond synchronously if the two battery cells 7 experience thermal runaway simultaneously or sequentially, providing initial heat buffer for each battery cell. Subsequently, the first phase change material of the phase change outlets 6 on both sides melts synchronously, and the spray nozzles 3 simultaneously spray high-speed fine streams of coolant to cool the battery cells on both sides synchronously in both directions, effectively improving the cooling rate and avoiding the spread of thermal runaway caused by lag in cooling on one side.

[0041] It is understandable that even if only one side has a phase change outlet 6 and a corresponding plug 2 is installed, phase change baffles 4 can be provided on both sides of the cold plate body 1 and fixed to the cold plate body 1 by a corresponding fixing frame 5. The phase change baffles 4 on the non-spray side can further enhance the thermal conductivity and improve the heat dissipation efficiency to provide a better heat exchange effect.

[0042] This utility model also provides a battery pack, including the above-mentioned battery module.

[0043] The above description is only a preferred embodiment of the present utility model and does not limit the implementation method and protection scope of the present utility model. Those skilled in the art should realize that all solutions obtained by equivalent substitutions and obvious changes made using the content of this specification and illustrations should be included within the protection scope of the present utility model.

Claims

1. A phase change liquid cooling plate, characterized in that, The device includes a cold plate body, the inner cavity of which is filled with coolant, and a plurality of plugs are embedded on at least one side panel of the cold plate body. Each plug has a spray nozzle that communicates with the inner cavity, and the spray nozzle is filled with a first phase change material.

2. The phase change liquid cooling plate according to claim 1, characterized in that, The plug is funnel-shaped.

3. The phase change liquid cooling plate according to claim 1, characterized in that, There are multiple spray nozzles, and each spray nozzle is distributed in a shower-like pattern.

4. The phase change liquid cooling plate according to claim 1, characterized in that, A phase change diaphragm is provided on at least one side of the cold plate body where the plug is embedded.

5. The phase change liquid cooling plate according to claim 4, characterized in that, The phase change separator is made of a second phase change material, and the phase change temperature of the second phase change material is lower than that of the first phase change material.

6. The phase change liquid cooling plate according to claim 4, characterized in that, The cold plate body and the phase change separator are connected and fixed by a fixed frame.

7. The phase change liquid cooling plate according to claim 4, characterized in that, The thickness of the phase change separator is 1mm-3mm.

8. The phase change liquid cooling plate according to claim 1, characterized in that, The coolant is an insulating coolant.

9. A battery module, characterized in that, It includes multiple battery cells, and a phase change liquid cooling plate as described in any one of claims 1-8 is provided between two adjacent battery cells.

10. A battery pack, characterized in that, Includes the battery module as described in claim 9.

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