A temperature-self-driven battery phase change thermal management device

Abstract

The present invention discloses a temperature-controlled, self-driven battery phase-change thermal management device. The device comprises a housing, a cavity for accommodating a battery, and a liquid cooling system for cooling the battery. The inner wall of the cavity is provided with a vacuum layer, which has an inner cavity containing a porous thermally conductive framework adsorbed with a powdered or granular phase-change material. The device autonomously regulates the battery's heat transfer performance to the external environment at different temperatures.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a temperature-self-driven battery phase change thermal management device. Background Art

[0002] As a core component of electric vehicles, battery safety is particularly important. The most important factor affecting battery safety is the battery's operating temperature. Temperature significantly impacts battery performance. When the battery is below its normal operating temperature, its internal resistance increases, its capacity decreases, and it may even fail to operate. When the battery is above its normal operating temperature, it may expand, leak, overheat, or even spontaneously combust. Therefore, the battery temperature must be controlled within a certain range. Different batteries have different normal operating temperature ranges. For example, lithium-ion batteries have a normal operating temperature range of -20°C to 60°C. Exceeding the upper or lower operating temperature limits will result in adverse effects.

[0003] Current battery thermal management technologies on the market primarily utilize liquid cooling. At low temperatures, the battery is typically heated directly by a heater plate or via antifreeze. At high temperatures, the antifreeze removes the heat from the battery. Given the high energy storage capacity of phase change materials (PCMs), which store heat at high temperatures and release it at low temperatures, they can achieve "peak shifting" of heat, altering the temporal and spatial distribution of heat and alleviating heat mismatches in time, space, and intensity. Therefore, PCMs are typically combined with liquid cooling systems to achieve battery thermal management, thereby enhancing temperature uniformity, preventing thermal runaway, and reducing energy consumption.

[0004] However, current thermal management systems struggle to balance heat dissipation at high temperatures and insulation at low temperatures. Therefore, when batteries operate in extremely cold environments, some of their energy is used to heat the battery. To minimize energy loss, it's necessary to strengthen the battery's insulation and reduce the amount of heat dissipated to the outside world. However, strengthening the battery's insulation can lead to significant heat generation in high-temperature environments or when the battery is operating under high load, making it difficult to dissipate heat to the outside world, creating a series of safety risks. Summary of the Invention

[0005] The purpose of the present invention is to solve the deficiencies of the above-mentioned technologies and to provide a temperature self-driven battery phase change thermal management device.

[0006] The present invention designs a temperature self-driven battery phase change thermal management device, comprising a box body, a cavity for accommodating a battery, and a liquid cooling system for cooling the battery in the cavity;

[0007] The inner wall of the cavity is provided with a vacuum layer, the vacuum layer has an inner cavity, and the inner cavity is provided with a porous heat-conducting skeleton. The porous heat-conducting skeleton is adsorbed with a powdered or granular phase change material. When the battery generates heat to a high temperature, the temperature of the vacuum layer rises, and the temperature of the porous heat-conducting skeleton also rises accordingly. The phase change material sublimates from a solid state to a gaseous state and diffuses into the vacuum layer, thereby increasing the thermal conductivity of the vacuum layer, thereby promoting continuous heat dissipation of the battery through the vacuum layer.

[0008] When the battery dissipates heat to a lower temperature, the temperature of the vacuum layer decreases, and the temperature of the porous thermal conductive skeleton also decreases accordingly. The gaseous phase change material re-condenses into powder or granules due to cooling and is adsorbed on the porous thermal conductive skeleton. At this time, the thermal conductivity coefficient in the vacuum layer decreases, making the battery thermally insulated and heat-keeping.

[0009] Preferably, a control system is further included, which includes a temperature control component and a heating wire arranged in a porous heat-conductive skeleton. The temperature control component is electrically connected to the battery and the heating wire. When the temperature control component senses that the battery dissipates heat and its temperature is too low, the temperature control component controls the heating wire to operate, so that the temperature of the vacuum layer increases, thereby making the battery thermally insulated and heat-keeping.

[0010] Further optimized, the temperature control component includes a magnetic contact and a bimetallic strip, the magnetic contact is connected to the battery, the bimetallic strip is connected to the heating wire, the bimetallic strip includes two metal strips, a first metal strip and a second metal strip, with different thermal expansion coefficients, the first metal strip is arranged close to the magnetic contact and can be connected or disconnected with the magnetic contact by magnetic attraction;

[0011] When the battery dissipates heat and its temperature is too low, the magnetic attraction force of the magnetic contact is greater than the thermal deformation force of the metal sheet 1 and the metal sheet 2, so that the magnetic contact and the metal sheet 1 are attracted and connected, and the heating wire works at this time;

[0012] When the battery temperature rises to a preset value through the operation of the heating wire, the thermal deformation force generated by the thermal deformation of the metal sheet 1 and the metal sheet 2 is greater than the magnetic attraction force of the magnetic contact, causing the magnetic contact to disconnect from the metal sheet 1. At this time, the heating wire stops working, thereby keeping the battery in an insulated state.

[0013] Preferably, the liquid cooling system includes a liquid cooling channel arranged along the battery arrangement direction, and the box body is provided with a cooling liquid inlet and a cooling liquid outlet communicating with the liquid cooling channel.

[0014] Preferably, the vacuum layer includes an inner wall surface and an outer wall surface, and the inner wall surface and the outer wall surface enclose an inner cavity.

[0015] For further optimization, the inner wall surface is made of a material with high thermal conductivity; and the outer wall surface is provided with a reflective layer to reflect the heat radiation on the inner wall surface.

[0016] Preferably, the box body is provided with a filling port for filling the phase change material.

[0017] Further optimization, the phase change material is iodine.

[0018] Further optimization is that after the phase change material is filled into the inner cavity of the vacuum layer, the vacuum layer is evacuated at low temperature so that the pressure of the inner cavity of the vacuum layer is reduced to 0.05 MPa or below, and then the phase change material is heated by a heating wire to sublime the phase change material and fill the inner cavity of the vacuum layer. Then, after cooling, the phase change material is re-condensed into powder or granules, so that most of the phase change material enters and is adsorbed in the porous heat-conductive skeleton.

[0019] Further optimization is performed, where the porous heat-conducting skeleton is arranged close to the inner wall surface.

[0020] The technical effect of the present invention is that a vacuum layer is added to the box that accommodates the battery, and a porous heat-conducting skeleton and phase change material are arranged in the vacuum layer. When the battery temperature rises, the phase change material sublimates from solid to gas, causing the air pressure in the vacuum layer to rise, thereby increasing the thermal conductivity coefficient in the vacuum layer, improving the battery's heat transfer ability to the external environment, accelerating the heat dissipation and cooling of the battery, and reducing the energy consumption required for heat dissipation.

[0021] When the battery temperature drops, the phase change material condenses from gas to solid, causing the air pressure in the vacuum layer to drop, thereby reducing the thermal conductivity coefficient in the vacuum layer and reducing the battery's ability to transfer heat to the external environment, thereby achieving thermal insulation for the battery and reducing the energy consumption required for heating.

[0022] That is, the phase change material undergoes solid-gas phase change at different temperatures, which increases or decreases the thermal conductivity coefficient in the vacuum layer, and enables the battery to dissipate heat or keep warm through the inner cavity, reducing the pressure of the cooling system. In conjunction with the liquid cooling system and the insulation system, the battery is prevented from being in an excessively low or high temperature state for a long time, and the battery is kept warm and dissipated in a timely and rapid manner. Therefore, the present invention realizes the spontaneous regulation of the battery's external heat transfer performance at different temperatures, realizes the self-driven regulation and management of the battery's insulation at low temperatures and heat dissipation at high temperatures, and improves energy management efficiency, playing a certain role in energy saving and emission reduction. At the same time, based on the characteristics of the phase change material, not only is the overall structure simple and easy to implement, but it can also be recycled and used multiple times in high and low temperature environments, realizing passive temperature control of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a cross-sectional view of the structure of the phase change material of the present invention when it is in a solid state;

[0024] Figure 2 It is a schematic diagram of the direction of the liquid cooling system in the present invention;

[0025] Figure 3 It is a cross-sectional view of the structure of the phase change material in the present invention when it is in a gaseous state.

[0026] In the figure: 1. Box body; 2. Cavity; 3. Battery; 4. Vacuum layer; 41. Inner wall; 42. Outer wall; 43. Inner cavity; 5. Porous thermal conductive skeleton; 6. Phase change material; 7. Heating wire; 8. Magnetic contact; 9. Metal sheet 1; 10. Metal sheet 2; 11. Liquid cooling channel; 12. Cooling liquid inlet; 13. Cooling liquid outlet; 14. Filling port. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0028] The present invention includes a box 1, which is provided with a cavity 2, and a battery 3 is placed in the cavity 2. The inner wall of the cavity 2 is provided with a vacuum layer 4, and the vacuum layer 4 has an inner cavity 43. The inner cavity 43 is evacuated to form a vacuum inner cavity. A porous thermal conductive skeleton 5 is provided in the inner cavity 43, and the porous thermal conductive skeleton 5 is formed to cover the inner wall of the cavity 2. The porous thermal conductive skeleton 5 is made of a material with high gas adsorption capacity such as carbon foam, metal foam, porous graphite, graphite fiber or metal wire mesh, and has the characteristics of high thermal conductivity and high porosity. The porous thermal conductive skeleton 5 adsorbs a powdered or granular phase change material 6.

[0029] like Figure 3 As shown, when the battery 3 generates heat to a high temperature, the temperature in the cavity 2 of the box 1 also rises accordingly. Through heat conduction, the temperature of the vacuum layer 4 also rises accordingly, and the temperature of the porous heat-conducting skeleton 5 in the vacuum layer 4 also rises accordingly. The phase change material 6 sublimates from a solid state to a gaseous state, and the phase change material 6 diffuses from the porous heat-conducting skeleton 5 into the vacuum layer 4, so that the gaseous phase change material 6 fills the vacuum layer 4, thereby increasing the thermal conductivity coefficient in the vacuum layer 4, and promoting the battery 3 to continuously dissipate heat to the outside through the vacuum layer 4; the porous heat-conducting skeleton 5 not only allows the phase change material 6 to be heated and sublimated uniformly and quickly, but also allows the phase change material 6 to be evenly distributed after condensation, which facilitates the phase change of the phase change material 6.

[0030] like Figure 1 As shown, when the battery 3 dissipates heat to a lower temperature, the temperature of the vacuum layer 4 decreases, and the temperature of the porous heat-conducting skeleton 5 also decreases accordingly. The gaseous phase change material 6 is cooled and re-condensed into powder or granules to be adsorbed on the porous heat-conducting skeleton 5. At this time, the thermal conductivity coefficient in the vacuum layer 4 decreases, making the battery 3 thermally insulated, thereby achieving heat preservation of the battery 3.

[0031] In this embodiment, the phase change material 6 is a material that is easy to sublime and whose saturated vapor pressure varies significantly at different temperatures, such as iodine. The saturated vapor pressure of iodine at different temperatures is shown in the following table:

[0032] .

[0033] When the temperature changes from -20°C to 60°C, the saturated vapor pressure of iodine changes from 0.04 Pa to 622.61 Pa, which corresponds to an increase of about 3 orders of magnitude in the thermal conductivity of the inner cavity 43 of the vacuum layer 4, from 10 -5 W / (m•K) becomes 10 -2 W / (m•K), realizing automatic regulation of the gas thermal conductivity of the inner cavity 43 of the vacuum layer 4 at different temperatures.

[0034] Taking the lithium-ion battery 3 as an example, the normal operating temperature of the battery 3 is -20℃~60℃, and generally needs to be controlled within the range of 0~40℃. When the battery 3 is in a low temperature environment for a long time, the heating wire 7 heats the battery 3 (the battery 3 can also be heated by the coolant) to keep the battery 3 at around 0℃. At this time, the internal pressure of the inner cavity 43 of the vacuum layer 4 is about 1.4Pa, and the thermal conductivity of the iodine vapor (i.e., the phase change material 6) in the inner cavity 43 is about 10 -5 W / (m•K), which isolates the heat dissipation of the battery 3 to the external environment and improves the energy utilization efficiency of the heating wire 7.

[0035] The cavity 2 is provided with a liquid cooling system for cooling the battery 3, such as Figure 2 As shown, the liquid cooling system includes a liquid cooling channel 11 arranged along the arrangement direction of the battery 3. The box body 1 is provided with a coolant inlet 12 and a coolant outlet 13 connected to the liquid cooling channel 11 for circulating and exchanging the coolant. The liquid cooling channel 11 can be a straight channel, a Z-shaped channel, a corrugated channel, etc., which is used to dissipate heat for the battery 3 during operation and can also provide heating for the battery 3 under extremely cold conditions.

[0036] The present invention also includes a control system, which includes a temperature control component and a heating wire 7 arranged in a porous heat-conducting skeleton 5. The temperature control component is electrically connected to the battery 3 and the heating wire 7. When the temperature control component senses that the battery 3 dissipates heat and its temperature is too low, the temperature control component controls the heating wire 7 to operate, so that the temperature of the vacuum layer 4 is increased to form an insulating state for the battery 3.

[0037] The temperature control component includes a magnetic contact 8 and a bimetallic strip. The magnetic contact 8 is connected to the battery 3, and the bimetallic strip is connected to the heating wire 7. That is, the heating wire 7, the bimetallic strip, the magnetic contact 8 and the battery 3 form a circuit loop. The bimetallic strip includes two metal sheets 1 9 and 10 with different thermal expansion coefficients. The metal sheet 1 9 is arranged close to the magnetic contact 8 and can be connected or disconnected with the magnetic contact 8 through magnetic attraction.

[0038] When the battery 3 dissipates heat and its temperature is too low, usually when the temperature is below -10°C, the magnetic attraction of the magnetic contact 8 is greater than the thermal deformation force of the metal sheet 1 9 and the metal sheet 2 10, so that the magnetic contact 8 and the metal sheet 1 9 are attracted to each other and connected, and the circuit is connected. At this time, the heating wire 7 works, the temperature of the porous heat-conducting skeleton 5 rises accordingly, and the heat is transferred to the cavity 2 through the vacuum layer 4 to provide heat for the battery 3.

[0039] When the temperature of the battery 3 rises to a preset value due to the operation of the heating wire 7, which is usually 0°C, the thermal deformation force generated by the thermal deformation of the metal sheet 1 9 and the metal sheet 2 10 is greater than the magnetic attraction of the magnetic contact 8, causing the magnetic contact 8 to be disconnected from the metal sheet 1 9 and the circuit to be disconnected. At this time, the heating wire 7 stops working, thereby keeping the battery 3 in an insulated state through the vacuum layer 4 to keep the battery 3 warm.

[0040] It should be noted that the magnetic contact 8 is made of magnetic material, and the metal sheet 19 is a magnetically attractive metal material, such as a thin iron sheet; the metal sheet 19 is fitted together with the metal sheet 2 10. As the temperature rises, the metal sheet 2 10 will undergo thermal deformation, driving the metal sheet 19 to deform together. The magnetic contact 8 is generally close to the metal sheet 19, so that when the metal sheet 19 is deformed, it can be magnetically connected or disconnected with the magnetic contact in a timely and accurate manner.

[0041] The relationship between the above-mentioned phase change material 6, control system and liquid cooling system is that when the temperature of the battery 3 rises or falls, the phase change material 6 automatically adjusts the thermal conductivity of the inner cavity 43 of the vacuum layer 4 by sublimating at high temperature and condensing at low temperature, that is, the thermal management requirements of the battery 3 to dissipate heat at high temperature and keep warm at low temperature are achieved through the vacuum layer 4; taking the lithium battery 3 as an example, the normal operating temperature of the battery 3 is -20°C to 60°C, but the temperature of the battery 3 generally needs to be controlled within the range of 0~40°C. Exceeding the upper limit of the operating temperature or falling below the lower limit of the operating temperature will cause adverse effects, so the temperature of the battery 3 is below -1 At 0°C, the control system controls the heating wire 7 to heat up, so that the battery 3 is heated until 0°C. At this time, the battery 3 is at a normal temperature, and then the control system controls the heating wire 7 to stop heating. That is, when the temperature of the battery 3 exceeds the controllable range of the phase change material 6, the control system can adjust the temperature of the battery 3 to the normal range in time; when the temperature is too high, that is, exceeds 40°C, the liquid cooling system works at this time, and the coolant enters from the coolant inlet 12, flows through the liquid cooling channel 11, and flows out from the coolant outlet 13 to cool the battery 3, the vacuum layer 4 and the cavity 2 at the same time. The cooling effect is very significant, so that the temperature is quickly reduced to below 40°C.

[0042] It should be noted that when the liquid cooling system lowers the temperature to 40°C, the air pressure in the inner cavity 43 of the vacuum layer 4 is about 133.47 Pa. The thermal conductivity of the iodine vapor in the inner cavity 43 of the vacuum layer 4 is about 10-2W / (m•K), which is similar to the thermal conductivity of air. The natural convection of the iodine vapor can dissipate heat to the external environment, thereby reducing the heat load of the liquid cooling system and thus reducing the power of the liquid cooling system.

[0043] Furthermore, vacuum layer 4 includes an inner wall surface 41 and an outer wall surface 42, which together form an inner cavity 43. Inner and outer walls 41, 42 are made of a material with a high thermal conductivity, such as aluminum alloy, which has a high thermal diffusion rate, enhancing heat transfer while maintaining strength. Outer wall surface 42 is mirrored or silver-plated to reflect thermal radiation from inner wall surface 41, reducing radiative heat dissipation from inner wall surface 41 to the outside world.

[0044] The battery 3 in the present invention is generally any type of battery 3 suitable for operating temperatures within this range, such as a lithium-ion battery 3 , a lead-acid battery 3 , and the like.

[0045] The housing 1 is provided with a filling port 14 for filling the phase change material 6. After the phase change material 6 fills the inner cavity 43 of the vacuum layer 4, the vacuum layer 4 is evacuated at a low temperature to reduce the pressure of the inner cavity 43 of the vacuum layer 4 to 0.01 MPa or below. The phase change material 6 is then heated by the heating wire 7, causing it to sublime and fill the inner cavity 43 of the vacuum layer 4. After cooling, the phase change material 6 recondenses into powder or granules, allowing most of the phase change material 6 to enter and be adsorbed within the porous thermally conductive skeleton 5. The heating allows the gaseous phase change material 6 to evenly and quickly fill the entire inner cavity 43 of the vacuum layer 4. The housing 1 is also provided with a sealing port communicating with the inner cavity 43 of the vacuum layer 4. The sealing port allows the inner cavity 43 of the vacuum layer 4 to be evacuated to maintain the vacuum level of the inner cavity 43.

[0046] Furthermore, the porous heat-conducting skeleton 5 is arranged close to or attached to the inner wall surface 41, so that heat transfer is faster and more timely.

[0047] The control system in the present invention also includes a control center, which includes various temperature sensors and a circuit control board. Since it is a conventional technology, the specific structure and working principle are not described here in detail.

[0048] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, any technical solution that is the same or similar to that of the present application falls within the scope of protection of the present invention.

Claims

1. A temperature self-driven battery phase change thermal management device, characterized in that: The invention comprises a box (1), wherein a cavity (2) for accommodating a battery (3) is provided in the box (1), and a liquid cooling system for cooling the battery (3) is provided in the cavity (2); The inner wall of the cavity (2) is provided with a vacuum layer (4), the vacuum layer (4) has an inner cavity (43), the inner cavity (43) is provided with a porous heat-conducting skeleton (5), the porous heat-conducting skeleton (5) is adsorbed with a powdered or granular phase-change material (6), when the battery (3) generates heat to a high temperature, the temperature of the vacuum layer (4) is increased, and the temperature of the porous heat-conducting skeleton (5) is also increased accordingly, the phase-change material (6) is sublimated from a solid state to a gaseous state, and diffuses into the vacuum layer (4), so that the thermal conductivity of the vacuum layer (4) is increased, thereby promoting the battery (3) to continuously dissipate heat to the outside through the vacuum layer (4); When the battery (3) dissipates heat to a lower temperature, the temperature of the vacuum layer (4) decreases, and the temperature of the porous heat-conducting skeleton (5) also decreases accordingly. The gaseous phase change material (6) is cooled and recondenses into powder or granules to be adsorbed on the porous heat-conducting skeleton (5). At this time, the thermal conductivity coefficient in the vacuum layer (4) decreases, so that the battery (3) forms a heat insulation and keeps the temperature. The invention also includes a control system, the control system including a temperature control component and a heating wire (7) arranged in a porous heat-conducting skeleton (5), the temperature control component being electrically connected to the battery (3) and the heating wire (7), and when the temperature control component senses that the battery (3) is dissipating heat and causing its temperature to be too low, the temperature control component controls the heating wire (7) to operate, thereby increasing the temperature of the vacuum layer (4), thereby allowing the battery (3) to form thermal insulation and maintain heat; The temperature control component includes a magnetic contact (8) and a bimetallic strip, wherein the magnetic contact (8) is connected to the battery (3), and the bimetallic strip is connected to the heating wire (7). The bimetallic strip includes two metal strips (1) and (2) (10) having different thermal expansion coefficients. The metal strip (1) is arranged close to the magnetic contact (8) and can be connected or disconnected with the magnetic contact (8) by magnetic attraction. When the battery (3) dissipates heat and its temperature is too low, the magnetic attraction of the magnetic contact (8) is greater than the thermal deformation force of the metal sheet 1 (9) and the metal sheet 2 (10), so that the magnetic contact (8) and the metal sheet 1 (9) are attracted to each other and connected, and the heating wire (7) works at this time; When the temperature of the battery (3) rises to a preset value through the operation of the heating wire (7), the thermal deformation force generated by the thermal deformation of the metal sheet (9) and the metal sheet (10) is greater than the magnetic attraction of the magnetic contact (8), so that the magnetic contact (8) is disconnected from the metal sheet (9), and the heating wire (7) stops working, thereby keeping the battery (3) in an adiabatic state; The vacuum layer (4) comprises an inner wall surface (41) and an outer wall surface (42), wherein the inner wall surface (41) and the outer wall surface (42) enclose an inner cavity (43), and the inner wall surface (41) is made of a material with a high thermal conductivity; and the outer wall surface (42) is provided with a reflective layer to reflect thermal radiation on the inner wall surface (41).

2. A temperature self-driven battery phase change thermal management device according to claim 1, characterized in that: The liquid cooling system comprises a liquid cooling channel (11) arranged along the arrangement direction of the batteries (3); the box body (1) is provided with a cooling liquid inlet (12) and a cooling liquid outlet (13) communicating with the liquid cooling channel (11).

3. The temperature self-driven battery phase change thermal management device according to claim 1, characterized in that: The box body (1) is provided with a filling port (14) for filling the phase change material (6).

4. The temperature self-driven battery phase change thermal management device according to claim 3, characterized in that: The phase change material (6) is iodine.

5. The temperature self-driven battery phase change thermal management device according to claim 4, characterized in that: After the phase change material (6) is filled into the inner cavity (43) of the vacuum layer (4), the vacuum layer (4) is evacuated at low temperature so that the pressure of the inner cavity (43) of the vacuum layer (4) is reduced to 0.01 MPa or below. Then, the phase change material (6) is heated by the heating wire (7) so that the phase change material (6) sublimates and fills the inner cavity (43) of the vacuum layer (4). Then, after cooling, the phase change material (6) is re-condensed into powder or granules, so that most of the phase change material (6) enters and is adsorbed in the porous heat-conducting skeleton (5).

6. The temperature self-driven battery phase change thermal management device according to claim 1, characterized in that: The porous heat-conducting skeleton (5) is arranged close to the inner wall surface (41).

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