Stepped phase change battery thermal management system
By incorporating stepped phase change materials inside the battery and utilizing the phase change temperature differences and thermal conductivity characteristics of different phase change materials, the problem of uneven battery temperature is solved, achieving internal temperature balance, extending battery life, and increasing power output.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHUNDE POLYTECHNIC
- Filing Date
- 2025-05-16
- Publication Date
- 2026-05-12
AI Technical Summary
Existing batteries experience uneven temperature during use, leading to capacity imbalance, power reduction, and accelerated aging. In particular, side reactions are accelerated in high-temperature regions, while capacity utilization is low in low-temperature regions, resulting in an increased rate of degradation throughout the battery's lifespan.
A stepped phase change material is used inside the battery. By using phase change materials with different phase change temperatures during liquid cooling, the internal temperature of the battery is kept balanced. Temperature balance is achieved by utilizing the phase change temperature difference and thermal conductivity characteristics of different phase change materials.
有效保持电池内部温度均衡，延长电池寿命，保障电池使用功率，减少电池老化，提升整体储能能力。
Smart Images
Figure CN224232735U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a stepped phase change battery thermal management system. Background Technology
[0002] Currently, new energy batteries are becoming increasingly popular. Batteries generate heat during use, and to ensure the temperature remains within a controllable range, a liquid cooling plate is typically installed at one end of the battery to reduce its temperature. However, this structure presents several problems. During the cooling process, the temperature of the battery end closer to the liquid cooling plate is lower than the end further away, resulting in uneven heat distribution. The consequences are: 1. Capacity imbalance and power reduction: The reaction rate accelerates in high-temperature regions and decreases in low-temperature regions, leading to a widening capacity difference between individual cells (capacity reduction accelerates in high-temperature regions, while capacity remains stable in low-temperature regions but overall energy storage capacity decreases). Differences in electrode material activity increase internal resistance, limiting the discharge rate and reducing system output power. 2. Accelerated battery aging: Side reactions (such as lithium plating and electrolyte decomposition) accelerate in high-temperature regions, while capacity utilization decreases in low-temperature regions, increasing the overall lifespan degradation rate by more than 30%. The temperature difference continues to widen during cycling, resulting in a non-linear increase in the capacity degradation rate. Summary of the Invention
[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a stepped phase change battery thermal management system. By using stepped phase change materials, the system maintains a balanced internal temperature of the battery during the liquid cooling process, thereby extending the battery's lifespan and ensuring its power output.
[0004] To achieve the above objectives, the technical solution of this utility model is as follows: it is a stepped phase change battery thermal management system, including...
[0005] Battery module and liquid cooling plate; the battery module includes one or more individual cells, each individual cell is arranged adjacent to the next, and a phase change space is left between adjacent individual cells; the liquid cooling plate is disposed at the end of the individual cell;
[0006] A stepped phase change material; the stepped phase change material includes a first phase change material and a second phase change material, the first phase change material and the second phase change material are respectively disposed in a phase change space, the first phase change material is located in the phase change space away from the liquid cooling plate, and the second phase change material is located in the other direction of the phase change space and is in contact with the liquid cooling plate; the phase change temperature of the first phase change material is greater than the phase change temperature of the second phase change material.
[0007] In this technical solution, the volume ratio of the first phase change material and the second phase change material in the phase change space is 7:3 to 3:7.
[0008] In this technical solution, the first phase change material is composed of sodium acetate trihydrate, polyethylene glycol, sodium pyrophosphate decahydrate, thermal conductivity enhancer, urea, and hydrogel.
[0009] In this technical solution, the first phase change material is composed of 62-75 wt% sodium acetate trihydrate, 3-8 wt% polyethylene glycol, 3-8 wt% sodium pyrophosphate decahydrate, 3-5 wt% thermal conductivity enhancer, 2-5 wt% urea, and 20-25 wt% hydrogel.
[0010] In this technical solution, the second phase change material is composed of disodium hydrogen phosphate dodecahydrate, sodium carbonate decahydrate, and hydrogel.
[0011] In this technical solution, the second phase change material is composed of 55-65 wt% disodium hydrogen phosphate dodecahydrate, 10-20 wt% sodium carbonate decahydrate, and 20-25 wt% hydrogel.
[0012] In this technical solution, the hydrogel is composed of polyvinyl alcohol and sodium alginate.
[0013] In this technical solution, the dry basis mass ratio of polyvinyl alcohol and sodium alginate is 3:1-4:1.
[0014] The advantages of this invention compared to existing technologies are: by using a stepped phase change material, the internal temperature of the battery is kept balanced during the liquid cooling process, thus extending the battery's lifespan and ensuring its power output. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation
[0016] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding of this utility model, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.
[0017] In the description of this utility model, the terms "upper", "lower", "right", "inner" and "left" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not require that this utility model must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0018] In this utility model, unless otherwise explicitly specified and limited, the terms "set" and "suite," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0019] like Figure 1 The above describes a stepped phase change battery thermal management system, characterized by including:
[0020] Battery module and liquid cooling plate 2; the battery module includes one or more individual cells 1, each of the individual cells 1 is arranged adjacent to each other, and a phase change space is left between the adjacent individual cells 1; the liquid cooling plate 2 is disposed at the end of the individual cell 1;
[0021] A stepped phase change material; the stepped phase change material includes a first phase change material 3 and a second phase change material 4, the first phase change material 3 and the second phase change material 4 are respectively disposed in a phase change space, the first phase change material 3 is located in the phase change space away from the liquid cooling plate 2, and the second phase change material 4 is located in the other direction of the phase change space and is in contact with the liquid cooling plate 2; the phase change temperature of the first phase change material 3 is greater than the phase change temperature of the second phase change material 4.
[0022] By employing stepped phase change materials, the battery maintains a balanced internal temperature during liquid cooling, extending battery life and ensuring battery power output.
[0023] First embodiment:
[0024] The first phase change material 3 consists of a hydrogel composed of polyvinyl alcohol and sodium alginate (dry basis mass ratio 4:1) 21wt%, sodium acetate trihydrate 65wt%, urea 3wt%, polyethylene glycol 3wt%, sodium pyrophosphate decahydrate 5wt%, and thermal conductivity enhancer 3wt%.
[0025] The second phase change material 4 is composed of 25wt% hydrogel of polyvinyl alcohol and sodium alginate (dry basis mass ratio 4:1), 65wt% disodium hydrogen phosphate dodecahydrate, and 10wt% sodium carbonate decahydrate.
[0026] The filling ratio is 6:4 between the upper and lower filling volumes, and the liquid cooling plate 2 adopts a serpentine flow channel.
[0027] Stress buffering effect:
[0028] The first phase change material 3 has an elongation at break, tensile strength, and Young's modulus of 115%, 0.61 MPa, and 5.43 MPa, respectively. Its phase change temperature is 45℃ and its enthalpy is 201 kJ / kg.
[0029] The second phase change material 4 has an elongation at break, tensile strength, and Young's modulus of 119.5%, 0.59 MPa, and 5.18 MPa, respectively. Its phase change temperature is 32 ℃ and its enthalpy is 195 kJ / kg.
[0030] When the battery pack starts operating, the individual battery cell 1 heats up, and the temperature gradually increases. The temperature of the lower half of the battery (accounting for about 40% of the battery height) reaches 35°C, and the second phase change material 4 begins to absorb heat and melt. The temperature of the bottom of the battery is maintained in the range of 35-38°C. The temperature of the upper half of the battery (accounting for about 60% of the battery height) gradually increases to 48°C, and the first phase change material 3 begins to absorb heat and melt. The temperature of the top of the battery is maintained in the range of 42-50°C. The liquid cooling plate 2 uses a 50% concentration ethylene glycol aqueous solution with an inlet temperature of 25°C and a coolant flow rate of 6L / min. The liquid cooling plate 2 is in direct contact with the lower second phase change material 4. The heat of the lower second phase change material 4 is carried away through the circulation of the coolant. The heat of the upper first phase change material 3 is carried away through the circulation of the coolant via the thermal conduction effect of the lower second phase change material 4. This achieves the recycling of the upper first phase change material 3 and the lower second phase change material 4. The average temperature of the battery pack is controlled at 35-42°C, and the maximum temperature of the individual battery cell is controlled below 50°C. Example
[0031] The first phase change material 3 consists of a hydrogel composed of polyvinyl alcohol and sodium alginate (dry basis mass ratio 4:1) 21wt%, sodium acetate trihydrate 65wt%, urea 5wt%, polyethylene glycol 1wt%, sodium pyrophosphate decahydrate 6wt%, and thermal conductivity enhancer 2wt%.
[0032] The second phase change material 4 is composed of 21 wt% hydrogel of polyvinyl alcohol and sodium alginate (dry basis mass ratio 4:1), 68 wt% disodium hydrogen phosphate dodecahydrate, and 11 wt% sodium carbonate decahydrate.
[0033] The filling ratio is 7:3, with the upper filling volume being equal to the lower filling volume. The liquid cooling plate 2 uses a serpentine flow channel.
[0034] Stress buffering effect:
[0035] The first phase change material has a phase change temperature of 42℃ and an enthalpy of 189kJ / kg.
[0036] The second phase change material has a phase change temperature of 33 ℃ and an enthalpy of 185 kJ / kg.
[0037] When the battery pack starts operating, the individual battery cell 1 heats up, and the temperature gradually increases. The temperature of the lower half of the battery (accounting for about 30% of the battery height) reaches 35°C, and the second phase change material 4 begins to absorb heat and melt. The temperature of the bottom of the battery is maintained in the range of 35-39°C. The temperature of the upper half of the battery (accounting for about 70% of the battery height) gradually increases to 45°C, and the first phase change material 3 begins to absorb heat and melt. The temperature of the top of the battery is maintained in the range of 40-45°C. The liquid cooling plate 2 uses a 50% concentration ethylene glycol aqueous solution with an inlet temperature of 25°C and a coolant flow rate of 1.5 m / s. The liquid cooling plate is in direct contact with the lower second phase change material 4. The heat of the lower second phase change material 4 is carried away by the coolant circulation. The heat of the upper first phase change material 3 is carried away by the coolant circulation through the heat conduction effect of the lower second phase change material 4. This realizes the recycling of the upper first phase change material 3 and the lower second phase change material 4. The average temperature of the battery pack is controlled at 35-43°C, and the maximum temperature of the individual battery cell is controlled below 45°C.
[0038] In this embodiment, the volume ratio of the first phase change material 3 and the second phase change material 4 in the phase change space is 7:3 to 3:7.
[0039] In this embodiment, the first phase change material 3 is composed of disodium hydrogen phosphate dodecahydrate, sodium carbonate decahydrate, and hydrogel.
[0040] In this embodiment, the composition consists of 55-65 wt% disodium hydrogen phosphate dodecahydrate, 10-20 wt% sodium carbonate decahydrate, and 20-25 wt% hydrogel.
[0041] In this embodiment, the second phase change material 4 is composed of sodium acetate trihydrate, polyethylene glycol, sodium pyrophosphate decahydrate, thermal conductivity enhancer, and hydrogel.
[0042] In this embodiment, the composition consists of 65-75 wt% sodium acetate trihydrate, 3-8 wt% polyethylene glycol, 3-8 wt% sodium pyrophosphate decahydrate, 3-5 wt% thermal conductivity enhancer, and 20-25 wt% hydrogel.
[0043] In this embodiment, the hydrogel is composed of polyvinyl alcohol and sodium alginate.
[0044] In this embodiment, the dry basis mass ratio of polyvinyl alcohol and sodium alginate is 3:1-4:1.
[0045] The embodiments of this utility model have been described in detail above with reference to the accompanying drawings, but this utility model is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations of these embodiments without departing from the principles and spirit of this utility model still fall within the protection scope of this utility model.
Claims
1. A stepped phase change battery thermal management system, characterized in that... include Battery module and liquid cooling plate (2); the battery module includes one or more single cells (1), each single cell (1) is arranged adjacent to each other, and a phase change space is left between adjacent single cells (1); the liquid cooling plate (2) is provided at the end of the single cell (1); A stepped phase change material; the stepped phase change material includes a first phase change material (3) and a second phase change material (4), the first phase change material (3) and the second phase change material (4) are respectively disposed in a phase change space, the first phase change material (3) is located in the phase change space away from the liquid cooling plate (2), and the second phase change material (4) is located in the other direction of the phase change space and is in contact with the liquid cooling plate (2); the phase change temperature of the first phase change material (3) is greater than the phase change temperature of the second phase change material (4).
2. The stepped phase change battery thermal management system according to claim 1, characterized in that... The volume ratio of the first phase change material (3) and the second phase change material (4) in the phase change space is 7:3 to 3:7.