Spiral battery heat dissipation and safety protection device

Abstract

The invention provides a spiral battery heat dissipation and safety protection device. The device comprises a spiral liquid cooling coil pipe wound on the outer wall of the lithium ion battery, wherein the coil pipe is provided with a cooling liquid inlet and a cooling liquid outlet and is used for cooling liquid circulation; a sleeve filled with a phase-change material is arranged on the outer side of the coil pipe and can be matched with the phase-change material and the shell for packaging and preventing leakage. During working, cooling liquid flows along the spiral flow channel to enhance heat exchange, and heat of the battery and the phase-change material is quickly taken away; when abnormal temperature rise or thermal runaway happens to the battery, the cooling liquid can flow out of the coil pipe and cover the outer surface of the battery, so that heat spreading is restrained, and the fire risk is reduced. The phase change material absorbs or releases latent heat near the phase change temperature to buffer the temperature rise on the surface of the battery. The device is compact in structure, high in heat dissipation efficiency and suitable for heat management and safety protection of single batteries, battery modules and battery packs.

Description

Technical Field

[0001] This invention belongs to the field of battery thermal management and safety protection technology, specifically relating to a spiral battery heat dissipation and safety protection device, which is suitable for temperature and safety control of lithium-ion battery packs. Background Technology

[0002] During charging and discharging, especially under conditions of fast charging, high-rate discharging, or prolonged high-load operation, lithium-ion battery packs generate a significant amount of heat due to electrochemical reactions, resistive heating, and polarization effects. When this heat cannot be dissipated effectively and promptly, the internal and surface temperatures of the battery will continue to rise, leading to a deterioration in its operating condition. Excessively high operating temperatures not only accelerate the aging of internal battery materials and the occurrence of side reactions, causing capacity decay and increased internal resistance, thus shortening battery life, but also reduce battery performance stability, affecting the reliable operation of the system. In extreme cases, excessively high battery temperatures may trigger failures such as separator shrinkage and electrolyte decomposition, further inducing thermal runaway reactions, and even causing serious safety accidents such as fires or explosions, posing a threat to equipment and personnel safety.

[0003] Existing heat dissipation methods include air cooling, liquid cooling, heat pipes, and phase change cooling. Air cooling has a simple structure but low heat exchange efficiency; liquid cooling has strong heat exchange capacity but is complex and requires high sealing; phase change materials have high heat capacity but poor thermal conductivity and hysteretic thermal response. In recent years, combining liquid cooling with phase change materials for battery thermal management has become a trend, combining active heat dissipation and passive thermal buffering effects. However, existing combinations of liquid cooling and phase change materials are mostly sandwich or cold plate types, which suffer from complex structures, high manufacturing costs, insufficient contact, and uneven heat dissipation. To address these shortcomings, this invention proposes a spiral battery heat dissipation and safety protection device. Its coils are tightly wrapped around the outer wall of the battery, allowing for the flow of lithium-ion battery-specific fire-extinguishing coolant, and are externally encased in a battery pack sleeve, achieving a comprehensive effect of efficient heat conduction, temperature buffering, and fire self-suppression. Summary of the Invention

[0004] The purpose of this invention is to provide a spiral battery heat dissipation and safety protection device with a compact structure, high heat dissipation efficiency and self-fire suppression function. It can effectively regulate the battery temperature under high temperature or abnormal conditions, and release fire extinguishing coolant to protect the battery when the battery catches fire.

[0005] To achieve the above objectives, the present invention proposes the following technical solution: a spiral battery heat dissipation and protection device, comprising a battery; a sleeve disposed outside the battery pack; a phase change material filled inside the sleeve; a liquid-cooled spiral tube wound around the outer wall of the battery; a coolant inlet; and a coolant outlet; the liquid-cooled spiral tube is spirally wound along the battery axis to form several turns, forming a continuous flow channel inside; the coolant flowing into the liquid-cooled spiral tube is a fire-extinguishing coolant specifically for lithium-ion batteries, which circulates and removes heat under normal operating conditions, and can automatically release and flow out when the battery experiences thermal runaway or fire, providing local fire extinguishing and heat insulation protection for the battery; the liquid-cooled spiral tube is covered with a phase change material, which absorbs heat and melts when the battery temperature reaches the phase change temperature, and releases heat when the temperature drops, achieving dual temperature control.

[0006] Preferably, the liquid-cooled spiral tube is made of copper, stainless steel, or aluminum alloy, possessing high thermal conductivity and good mechanical strength, enabling it to effectively conduct heat generated by the battery body to the coolant flowing inside the tube during battery operation. The liquid-cooled spiral tube has at least one thermally triggered failure section along its length. The melting temperature or structural failure temperature of this section is lower than the corresponding temperature of the other sections of the spiral tube, allowing it to preferentially undergo structural failure when the battery experiences abnormal temperature rise, thereby releasing the coolant.

[0007] This structure enables the liquid-cooled spiral tube to maintain stable heat exchange capacity under long-term high-power discharge or charging conditions, thereby ensuring that the battery body is always within a safe temperature range and preventing thermal runaway caused by local overheating. If thermal runaway occurs, the temperature rise is suppressed by the outflow of coolant.

[0008] Preferably, the phase change material is a material with high heat capacity and a suitable phase change temperature range, such as paraffin-based, fatty acid-based, or salt-based phase change materials, or a composite phase change material containing thermally conductive fillers (such as graphite, carbon nanotubes, or metal oxide nanoparticles). When the battery surface temperature reaches or exceeds the phase change temperature, the phase change material absorbs a large amount of heat and undergoes a solid-liquid phase change to buffer the temperature rise, delay heat diffusion, and reduce the risk of battery overheating.

[0009] This phase change composite structure can achieve efficient heat absorption and release processes under conditions of drastic temperature fluctuations, improve the thermal inertia and response stability of the heat dissipation system, and ensure that the battery maintains balanced performance and controllable temperature under different operating conditions.

[0010] Preferably, the coolant is a fire-extinguishing coolant specifically designed for lithium-ion batteries. This coolant possesses high specific heat capacity and good fluidity during normal operation, allowing it to circulate and remove heat within the liquid-cooled spiral tube. In the event of thermal runaway or fire within the battery, the coolant can automatically flow out through a venting structure to cool and extinguish the fire on the battery's outer wall. This coolant exhibits electrical insulation, flame retardancy, and high-temperature resistance, and is recyclable. This achieves integrated active thermal management and emergency fire suppression.

[0011] This design provides it with safety protection functions, enabling the heat dissipation device to have a triple function of temperature control, fire extinguishing and heat diffusion inhibition, thereby improving the overall reliability and safety of the system.

[0012] Preferably, the device may be equipped with an external housing made of high-temperature and corrosion-resistant materials, such as aluminum alloy, stainless steel, or high-performance engineering plastics, to encapsulate the battery body, liquid-cooled spiral tube, and phase change material. This housing further protects against external impacts, liquid leakage, and thermal radiation damage, ensuring long-term stable operation of the heat dissipation device under extreme conditions.

[0013] This structure enables the device to maintain good sealing and structural strength under complex operating conditions such as high temperature, high humidity, and vibration, thereby improving the service life and safety stability of the battery heat dissipation system.

[0014] Preferably, the liquid-cooled spiral tube can adopt a variable spacing design during the winding process. The spacing between the coil turns can be adjusted according to the heat distribution differences in different areas of the battery body, so that the coolant has a higher flow density in the high heat flux density area and achieves precise temperature control in different zones.

[0015] This structure can effectively avoid local overheating of the battery, making the battery temperature distribution more uniform, thereby further improving the overall heat dissipation performance and thermal balance stability of the thermal management system.

[0016] The beneficial effects of this invention are as follows: This invention employs a composite cooling method combining spiral liquid cooling and phase change materials. Through the synergistic effect of active liquid cooling and passive phase change heat absorption, it enhances the control capability of lithium-ion battery operating temperature and the overall heat dissipation effect. Compared with methods that use liquid cooling or phase change materials alone, the composite cooling method proposed in this invention can effectively reduce the maximum temperature during battery operation, and its cooling effect is more significant. Figure 5 The spiral liquid cooling coil structure extends the flow path of the coolant and increases the heat exchange area with the battery surface, which facilitates heat conduction and diffusion in the phase change material, thereby further reducing the battery's maximum temperature and suppressing the generation of local hot spots. Comparative results under different coolant flow rates show that the maximum battery temperature decreases with increasing coolant flow rate. Figure 6This is because increased flow rate enhances convective heat transfer between the coolant and the inner wall of the liquid-cooled coil, accelerating the heat transfer process from the battery to the coolant, thereby further improving the overall heat dissipation effect. When the battery pack experiences abnormal temperature rise and reaches the preset trigger condition, the thermal trigger failure section set in the liquid-cooled spiral tube preferentially undergoes structural failure, causing the coolant to be released and act on the outer surface of the battery, thereby blocking heat accumulation and inhibiting heat spread, improving the system's safety protection capability under extreme operating conditions. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of a spiral battery heat dissipation and safety protection device disclosed in this invention.

[0019] Figure 2 This is a schematic diagram of a liquid-cooled spiral tube and a battery, which are disclosed in this invention as a spiral battery heat dissipation and safety protection device.

[0020] Figure 3 This is a schematic diagram of a single-cell cooling structure for a spiral battery heat dissipation and safety protection device disclosed in this invention.

[0021] Figure 4 This is a schematic diagram of the outer sleeve structure of a spiral battery heat dissipation and safety protection device disclosed in this invention.

[0022] Figure 5 This is a schematic diagram comparing the maximum temperature of the present invention with that of no-cooling design, liquid-cooling design, and phase change material cooling design.

[0023] Figure 6 This is a schematic diagram comparing the maximum battery temperature under different cooling flow rates using a composite cooling structure.

[0024] The diagram is labeled as follows: 1. Battery; 2. Liquid-cooled spiral tube; 3. Phase change material; 4. Battery pack sleeve; 5. Coolant inlet; 6. Coolant outlet; 7. Primary coil; 8. Secondary coil; 9. Tertiary coil; 10. Quaternary coil; 11. Fifth coil; 12. Sixth coil; 13. Seventh coil; 14. Eighth coil; 15. Base. Detailed Implementation

[0025] The specific implementation methods of the present invention are described below with reference to the embodiments and accompanying drawings: Embodiment 1, as shown in the attached drawings. Figure 1 ~Attached Figure 3 As shown, this embodiment provides a composite battery heat dissipation and safety protection device combining a spiral coil and a phase change material, including a battery 1, a liquid-cooled spiral tube 2 wound around the outer wall of the battery 1, and a phase change material 3 disposed on the outside of the liquid-cooled spiral tube 2. The battery pack sleeve 4 is filled with the phase change material 3. In this example, RT31 is used as the phase change material.

[0026] The battery 1 is a standard 18650 cylindrical lithium-ion battery. In this embodiment, the battery 1 operates at a 6C discharge rate. The liquid-cooled spiral tube 2 is continuously wound along the axial direction of the battery 1 to form several turns. In this example, a total of 8 turns are wound, with a spacing A of 7.75 mm between each turn. Figure 2 The liquid-cooled spiral tube is tightly wound around the outer wall of the battery. Coolant is introduced into the spiral tube during battery discharge, and its inner cavity forms a flow channel for the coolant to increase the heat exchange area and enhance convective heat transfer. The battery pack sleeve 4 covers the outside of the phase change material 3. In this example, the sleeve height is 65mm and the minimum edge thickness is 1mm. When the battery temperature rises and reaches its phase change temperature, the phase change material 3 absorbs latent heat and undergoes a phase change, thus buffering the battery temperature rise. When the battery temperature decreases, the phase change material 3 releases heat to maintain a relatively stable battery temperature.

[0027] The coolant inlet 5 and coolant outlet 6 have lengths of 1.5 mm and widths of 1 mm, respectively, and are located at both ends of the liquid-cooled spiral tube 2. Coolant enters the liquid-cooled spiral tube 2 through the coolant inlet 5, flows along a spiral path under the drive of external circulation, and is finally discharged through the coolant outlet 6. In this embodiment, the basic average flow velocity of the coolant within the liquid-cooled spiral tube 2 is set to 0.025 m / s, and subsequent tests were conducted at different flow velocities of 0.05 m / s, 0.75 m / s, and 0.1 m / s.

[0028] Preferably, the liquid-cooled spiral tube 2 is made of copper, stainless steel or aluminum alloy and has a wall thickness of 0.5 mm to ensure good thermal conductivity and structural strength, so that it can still operate stably under high heat load conditions such as 6C discharge.

[0029] As attached Figure 3 As shown, the liquid-cooled spiral tube 2 forms a multi-stage coil structure along the axial direction, including a primary coil 7, a secondary coil 8, a tertiary coil 9, a quaternary coil 10, a quinary coil 11, a sixth coil 12, a seventh coil 13, and an octagonal coil 14. After the coolant enters through the coolant inlet 5, the contact area increases in both the axial and circumferential directions from the primary coil 7 to the octagonal coil 14, thereby improving the convective heat transfer performance.

[0030] During the discharge of battery 1 at a 6C rate, the coolant flows along the spiral coil at a flow rate of 0.025 m / s, continuously carrying away the heat generated by the battery through liquid convection heat transfer and tube wall heat conduction. At the same time, the phase change material 3 buffers the temperature rise by absorbing latent heat, which helps to reduce the maximum temperature of the battery and improve the uniformity of axial temperature distribution.

[0031] The beneficial effects of this invention are as follows: This invention employs a composite cooling method combining spiral liquid cooling and phase change materials. Through the synergistic effect of active liquid cooling and passive phase change heat absorption, it enhances the control capability of lithium-ion battery operating temperature and the overall heat dissipation effect. Compared with methods that use liquid cooling or phase change materials alone, the composite cooling method proposed in this invention can effectively reduce the maximum temperature during battery operation, and its cooling effect is more significant. Figure 5 The spiral liquid cooling coil structure extends the flow path of the coolant and increases the heat exchange area with the battery surface, which facilitates heat conduction and diffusion in the phase change material, thereby further reducing the battery's maximum temperature and suppressing the generation of local hot spots. Comparative results under different coolant flow rates show that the maximum battery temperature decreases with increasing coolant flow rate. Figure 6 This is because increased flow rate enhances the convective heat transfer intensity between the coolant and the inner wall of the liquid cooling coil, accelerating the heat transfer process from the battery to the coolant, thereby further improving the overall heat dissipation effect.

[0032] The device described in this embodiment is not only applicable to single cylindrical lithium-ion batteries, but also to battery packs, battery modules, and power battery packs composed of multiple batteries. By adjusting the number of coil stages, helical pitch, coolant flow rate, and phase change material parameters, efficient and reliable battery thermal management and safety protection can be achieved under different discharge rates.

[0033] The foregoing provides a detailed description of a spiral battery heat dissipation and safety protection device. This document illustrates the principles and preferred embodiments of the invention through specific examples. These embodiments are merely for the purpose of helping to understand the technical solutions and core ideas of the invention and should not be considered as limiting the scope of protection of the invention. It should be particularly noted that those skilled in the art can make several equivalent modifications, improvements, or optimizations to the invention without departing from its basic principles. Adjustments in structural form, material selection, manufacturing process, or other technical features should all be considered to fall within the scope of protection claimed in this application.

Claims

1. A spiral-type battery heat dissipation and safety protection device, characterized in that: The system includes a battery body (1), a liquid-cooled spiral tube (2) wound around the outer wall of the battery body (1), the liquid-cooled spiral tube (2) being continuously coiled along the battery axis to form several turns, with flow channels for coolant to flow through, thereby increasing the heat exchange area and enhancing convective heat transfer; a phase change material (3) is wrapped around the outside of the liquid-cooled spiral tube (2), the outside of which is wrapped by a metal sleeve (4); a base (15) is provided at the bottom; wherein, the liquid-cooled spiral tube (2) has at least one thermally triggered failure section along its length, the melting temperature or structural failure temperature of the thermally triggered failure section being lower than that of the other sections of the liquid-cooled spiral tube (2); under normal battery operation... In this state, the coolant flows along the spiral path in the liquid-cooled spiral tube (2), and by extending the flow path and increasing the contact area with the battery body (1), it carries away the heat generated by the battery body (1). When the battery temperature rises, the phase change material absorbs latent heat to reduce the surface temperature of the battery body (1), thereby slowing down the rapid temperature rise and inhibiting the battery thermal runaway and combustion trend. When the battery experiences abnormal temperature rise and the thermal trigger failure section reaches its trigger temperature, the thermal trigger failure section melts or ruptures, causing the coolant to be released from the liquid-cooled spiral tube (2) and act on the outer surface of the battery body (1) to block heat accumulation and inhibit heat spread.

2. The apparatus according to claim 1, characterized in that: The liquid-cooled spiral tube (2) is continuously spirally wound along the battery axis, with a length of 400-600mm. It includes a first-stage coil (7), a second-stage coil (8), a third-stage coil (9), a fourth-stage coil (10), a fifth-stage coil (11), a sixth-stage coil (12), a seventh-stage coil (13), and an eighth-stage coil (14) connected in sequence. The coil has an inlet (5) above the battery and an outlet (6) below the battery, so that the coolant flows in both the axial and circumferential directions to improve the uniformity of the axial temperature distribution of the battery body (1).

3. The apparatus according to claim 1 or 2, characterized in that: The thermally triggered failure zone is formed by using low-melting-point materials, thinned wall structures, or hot-melt polymer materials.

4. The thermally triggered failure section according to claim 3, characterized in that: The triggering temperature of the thermally triggered failure zone is 60°C to 100°C.

5. The phase change material according to claim 1, characterized in that: The phase change material has a phase change temperature of 30°C to 35°C and is used to absorb heat during the process of battery temperature rise to enhance the overall heat dissipation effect.

6. The coolant according to claim 1, characterized in that: The coolant is a low-conductivity, low-corrosive battery coolant, used to circulate within the liquid-cooled spiral tube (2) for heat exchange.

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