Battery thermal management system, vehicle and thermal management method

Abstract

This invention belongs to the field of battery technology and discloses a battery thermal management system, a vehicle, and a thermal management method. The battery thermal management system includes a housing unit, a battery cooling unit, and a heat storage unit. The housing unit includes an inner shell and an outer shell. The inner shell is used to house the battery, and the battery has a cooling channel. The inner shell is a heat-conducting component and is located inside the outer shell. An interlayer is provided between the inner shell and the outer shell. The battery cooling unit includes a first heat exchanger, which is connected to the cooling channel through a liquid supply pipe and a liquid return pipe. A first medium can flow in the liquid supply pipe, the liquid return pipe, and the cooling channel. The heat storage unit includes a phase change material, which is disposed in the interlayer. The phase change material can absorb the heat of the first medium in the liquid return pipe and can also heat the battery to utilize the residual heat of the battery cooling unit to heat the battery that has stopped supplying power.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a battery thermal management system, a vehicle, and a thermal management method. Background Technology

[0002] Proton exchange membrane fuel cell (PEMFC) vehicles are a key development direction for new energy vehicles due to their advantages such as zero emissions and high efficiency. However, the low-temperature cold-start performance of fuel cells is one of the key bottlenecks restricting their large-scale promotion in cold regions. In environments below 0°C, water generated on the cathode side inside the fuel cell is prone to freezing, clogging the catalyst and diffusion layers, hindering electrochemical reactions, and the expansion of ice crystals may cause irreversible physical damage to the membrane electrode assembly.

[0003] To address the aforementioned technical challenges, existing technologies primarily focus on increasing the temperature of fuel cells through external auxiliary heating. For example, solid hydrogen storage materials react with hydrogen to release heat, which is then absorbed by circulating water and used to heat the fuel cell via a heat exchanger. Alternatively, a gas heater is added to directly heat the coolant cooling the fuel cell by burning hydrogen, thereby heating the fuel cell.

[0004] The aforementioned technical solutions require the consumption of additional hydrogen or electricity, reducing the overall vehicle energy efficiency. Furthermore, the heating process takes several minutes to tens of minutes, resulting in long start-up times and a poor user experience. Therefore, there is an urgent need to propose a battery thermal management system, a vehicle, and a thermal management method to address these technical problems. Summary of the Invention

[0005] The first objective of this invention is to provide a battery thermal management system that can utilize the waste heat from the battery cooling unit to heat a battery that has stopped supplying power.

[0006] To achieve this objective, the present invention adopts the following technical solution: The battery thermal management system includes: The housing unit includes an inner shell and an outer shell. The inner shell is used to house the battery, which has cooling channels. The inner shell is a heat-conducting component and is located inside the outer shell. A sandwich layer is provided between the inner shell and the outer shell. A battery cooling unit includes a first heat exchanger, which is connected to a cooling channel via a liquid supply pipe and a liquid return pipe, and a first medium can flow in the liquid supply pipe, the liquid return pipe and the cooling channel. The heat storage unit includes a phase change material disposed in the interlayer. The phase change material can absorb the heat of the first medium in the return pipe and can also heat the battery.

[0007] Optionally, the interlayer is provided with reserved expansion space.

[0008] Optionally, the phase change material is a solid-liquid phase change material, and the reserved expansion space is located at least at the bottom of the interlayer, with an expansion absorption element provided in the reserved expansion space.

[0009] Optionally, the phase change material is a solid-liquid phase change material, which has thermal insulation capabilities when it is in a solid state; And / or, the housing is a heat-insulating component.

[0010] Optionally, the heat storage unit also includes a heat-conducting element disposed within the interlayer.

[0011] Optionally, the heat storage unit further includes a heating channel and a second medium, the heating channel being located within the interlayer; The heat storage unit also includes a second heat exchanger, which is provided with a first heat exchange channel and a second heat exchange channel. The first medium can circulate between the first heat exchange channel and the return liquid pipe, and the second medium can circulate between the second heat exchange channel and the heating channel. Alternatively, the second medium can circulate between the heating channel and the return pipe.

[0012] A second object of the present invention is to provide a vehicle that can use the waste heat from the battery cooling unit to heat the battery.

[0013] To achieve this objective, the present invention adopts the following technical solution: The vehicle, including the aforementioned battery thermal management system.

[0014] A third objective of this invention is to provide a thermal management method that can utilize the residual heat of the battery cooling unit to heat a battery that has stopped supplying power.

[0015] To achieve this objective, the present invention adopts the following technical solution: A thermal management method for controlling the aforementioned battery thermal management system, the thermal management method including: After the battery stops supplying power, T1 and T2 are detected. T1 is the temperature of the first medium in the return pipe, and T2 is the temperature of the phase change material or the battery temperature. If T1 > T2 > T3, then the phase change material absorbs the heat of the first medium in the return pipe, and T3 is the phase change temperature of the phase change material. Continuous monitoring of T1 and T2; When T1 < T2, or when T1 < T3, the phase change material stops absorbing heat from the first medium in the return pipe.

[0016] Optionally, after the battery stops supplying power, T2 is detected when battery power is needed; If T2≥T4, the battery starts supplying power. T4 is the first preset temperature, which is greater than or equal to 0℃. If T2 < T4, then the auxiliary heating unit heats the battery.

[0017] Optionally, when the battery stops supplying power, the circulation of the first medium between the supply pipe, the return pipe, and the cooling channel is stopped.

[0018] The beneficial effects of this invention are: When the battery is supplying power, the first heat exchanger delivers a low-temperature first medium to the cooling channel through a supply pipe. This first medium absorbs heat from the battery within the cooling channel, thus cooling the battery. The high-temperature first medium, having absorbed heat from the battery, flows back to the first heat exchanger through a return pipe. When the battery stops supplying power, the first heat exchanger stops delivering the low-temperature first medium to the cooling channel, thus stopping battery cooling. At this time, the phase change material within the interlayer absorbs heat from the high-temperature first medium in the return pipe and undergoes a phase change, achieving waste heat recovery and storage from the battery cooling unit. When the phase change material releases heat and undergoes another phase change, the released heat is transferred to the battery through the inner shell, achieving the effect of heating the battery.

[0019] This battery thermal management system utilizes the "peak-shifting and valley-filling" effect of phase change materials to heat batteries that have stopped supplying power. This allows batteries that have stopped supplying power in low-temperature environments to maintain a suitable temperature (e.g., above 0°C). This not only prevents damage to the battery when it is restored to power at low temperatures but also enables the battery to quickly resume power supply in cold environments, thus extending battery life and improving user experience. Furthermore, the phase change material absorbs waste heat that would otherwise be dissipated into the environment through the first heat exchanger, reducing the energy consumption of the battery thermal management system. Attached Figure Description

[0020] Figure 1 This is a cross-sectional structural schematic diagram of the shell unit provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the battery thermal management system provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the battery thermal management system provided in the embodiment of the present invention when it is in thermal storage mode; Figure 4 This is a flowchart of the thermal management method provided in an embodiment of the present invention.

[0021] In the picture: 10. Battery; 100. Housing unit; 110. Inner shell; 120. Outer shell; 130. Interlayer; 131. Reserved expansion space; 140. Expansion absorption element; 210. First heat exchanger; 220. Liquid supply pipe; 230. Liquid return pipe; 240. First circulation pump; 250. Three-way valve; 260. Branch pipe; 310. Heat-conducting element; 320. Heating channel; 330. Second heat exchanger; 331. First heat exchange channel; 332. Second heat exchange channel; 340. Two-way valve; 350. Second circulation pump. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should also be noted that, for ease of description, only the parts relevant to the present invention are shown in the drawings, not the entire structure. It is understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it.

[0023] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" 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 or an electrical connection; they can refer to 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 invention based on the specific circumstances.

[0024] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0026] This embodiment provides a battery thermal management system that can utilize the waste heat from the battery cooling unit to heat a battery that has stopped supplying power.

[0027] Specifically, such as Figures 1 to 3 As shown, the battery thermal management system includes a housing unit 100, a battery cooling unit, and a heat storage unit. The housing unit 100 includes an inner shell 110 and an outer shell 120. The inner shell 110 is used to house the battery 10, and the battery 10 is provided with a cooling channel (not shown in the figure). The inner shell 110 is a heat-conducting component and is located inside the outer shell 120. An interlayer 130 is provided between the inner shell 110 and the outer shell 120. The battery cooling unit includes a first heat exchanger 210, which is connected to the cooling channel through a liquid supply pipe 220 and a liquid return pipe 230. A first medium can flow in the liquid supply pipe 220, the liquid return pipe 230, and the cooling channel. The heat storage unit includes a phase change material (not shown in the figure), which is disposed in the interlayer 130. The phase change material can absorb the heat of the first medium in the liquid return pipe 230 and can heat the battery 10.

[0028] In this embodiment, the battery 10 is a fuel cell. Of course, in other embodiments, the battery 10 can be other types of batteries, which will not be listed here.

[0029] The first medium can be cooling water, cooling gas, or refrigerant. The second medium can be water, air, or other flowing media with thermal conductivity.

[0030] Based on the above design, when the battery 10 is supplying power, the first heat exchanger 210 delivers a low-temperature first medium to the cooling channel through the supply pipe 220. This first medium absorbs heat from the battery 10 within the cooling channel, thus cooling the battery 10. The high-temperature first medium, having absorbed heat from the battery 10, flows back to the first heat exchanger 210 through the return pipe 230. When the battery 10 stops supplying power, the first heat exchanger 210 stops delivering the low-temperature first medium to the cooling channel, thus stopping the cooling of the battery 10. At this time, the phase change material within the interlayer 130 absorbs the heat from the high-temperature first medium in the return pipe 230 and undergoes a phase change, achieving waste heat recovery and storage of the battery cooling unit. When the phase change material releases heat and undergoes another phase change, the released heat is transferred to the battery 10 through the inner shell 110, achieving the effect of heating the battery 10.

[0031] This battery thermal management system utilizes the "peak shaving and valley filling" effect of phase change materials to heat the battery 10 when it is not supplying power. This allows the battery 10, which is not supplying power in low-temperature environments, to maintain a suitable temperature (e.g., above 0°C). This not only prevents damage to the battery 10 when it is resuming power at low temperatures but also enables the battery 10 to quickly resume power supply in low-temperature environments. Simultaneously, it extends the battery 10's lifespan and improves the user experience. Furthermore, the phase change material absorbs waste heat that would otherwise be dissipated into the environment through the first heat exchanger 210, thus reducing the energy consumption of the battery thermal management system.

[0032] Furthermore, the inner shell 110 is made of materials with good thermal conductivity, such as aluminum alloy, copper, or aluminum.

[0033] Optionally, the outer casing 120 is a heat insulation component to prevent the heat of the phase change material from being lost to the external environment through the outer casing 120, ensuring that all the heat stored in the phase change material can be used to heat the battery 10, while also preventing the heat of the battery 10 from being lost to the external environment, thus achieving the effect of heat preservation for the battery 10.

[0034] Furthermore, the outer shell 120 is made of materials with good thermal insulation properties, such as engineering plastics or stainless steel.

[0035] Optionally, the aforementioned interlayer 130 is a sealed interlayer to ensure the heat preservation effect on the battery 10.

[0036] Optionally, the interlayer 130 is provided with a reserved expansion space 131. When the phase change medium undergoes a phase change, a volume expansion phenomenon will occur (taking paraffin as an example, the volume expansion coefficient of paraffin during the phase change process is about 10%-15%). In order to prevent the expanding phase change medium from damaging the inner shell 110 and the outer shell 120, a reserved expansion space 131 is provided in the interlayer 130 to protect the inner shell 110 and the outer shell 120.

[0037] Furthermore, the phase change material is a solid-liquid phase change material, and the reserved expansion space 131 is located at least at the bottom of the interlayer 130. An expansion absorption element 140 is provided within the reserved expansion space 131. To prevent damage to the inner shell 110 and outer shell 120 during the solidification and expansion of the phase change material, it is necessary to ensure that the phase change material, when in a liquid state, does not completely fill the interlayer 130. Under the influence of gravity, the liquid phase change material tends to accumulate at the bottom and middle of the interlayer 130, leaving the top of the interlayer 130 without liquid phase change material. This results in uneven distribution of the phase change material within the interlayer 130, thus affecting the uniformity of heating the battery 10. In this embodiment, an expansion absorption element 140 is provided within the reserved expansion space 131, causing the liquid level of the liquid phase change material to rise, thereby ensuring that the top of the interlayer 130 is also filled with liquid phase change material. This improves the uniformity of heating the battery 10 when the liquid phase change material exothermically solidifies. On the other hand, when the liquid phase change material solidifies and expands, the expansion absorption element 140 can absorb at least part of the expansion of the phase change material, thus preventing the expanding phase change material from damaging the inner shell 110 and the outer shell 120.

[0038] Furthermore, the expansion-absorbing element 140 is a corrugated tube or an elastic foam. The corrugated tube has a certain degree of flexibility. When the phase change material expands and compresses the corrugated tube, the corrugated tube deforms to absorb at least part of the expansion of the phase change material. The elastic foam has a certain degree of elasticity. When the phase change material expands and compresses the corrugated tube, the elastic foam deforms to absorb at least part of the expansion of the phase change material.

[0039] In this embodiment, the interlayer 130 is provided with reserved expansion spaces 131 in the circumferential direction, top, and bottom, and expansion absorption elements 140 are provided in the circumferential direction, top, and bottom of the interlayer 130, thereby further improving the uniformity of the distribution of the liquid phase change material in the interlayer 130. Of course, in other embodiments, the reserved expansion space 131 may only be provided at the bottom of the interlayer 130, that is, the expansion absorption element 140 may only be provided at the bottom of the interlayer 130.

[0040] Optionally, the phase change material is a solid-liquid phase change material, which has thermal insulation capabilities when it is solid. Therefore, the solid phase change material can form a thermal insulation layer between the battery 10 and the external environment, preventing heat loss from the battery 10 to the external environment. Combined with the outer shell 120 in this embodiment serving as a thermal insulation component, the solid phase change material and the outer shell 120 form two layers of thermal insulation between the battery 10 and the external environment, which further helps to slow down the heat loss from the battery 10 to the external environment and improves the heat preservation effect of the battery 10.

[0041] In this embodiment, the phase change material is pure paraffin wax, which has a melting point range of 50℃-65℃ and a thermal conductivity of approximately 0.2 W / m·K in solid form, exhibiting good thermal insulation properties. Of course, in other embodiments, the phase change material can also be hexadecanoic acid, octadecanoic acid, or alkanes, etc., which will not be listed here.

[0042] Optionally, the heat storage unit also includes a heat-conducting element 310, which is disposed within the interlayer 130 to improve the heating effect of the phase change material on the battery 10. Furthermore, placing the heat-conducting element 310 within the interlayer 130 facilitates the rise of the liquid level in the liquid phase change material.

[0043] Furthermore, the heat-conducting elements 310 are evenly distributed on the outer wall of the inner shell 110, which not only further increases the heat transferred to the battery 10, but also improves the structural strength of the inner shell 110, preventing the inner shell 110 from deforming due to the compression caused by the expansion of the phase change material.

[0044] Optionally, the heat-conducting element 310 may be expanded graphite or foamed metal, etc.

[0045] Optionally, the heat storage unit further includes a heating channel 320 and a second medium, the heating channel 320 being located within the interlayer 130. The heat storage unit also includes a second heat exchanger 330, which has a first heat exchange channel 331 and a second heat exchange channel 332. The first medium can circulate between the first heat exchange channel 331 and the return pipe 230, and the second medium can circulate between the second heat exchange channel 332 and the heating channel 320. This allows the phase change material to absorb heat from the first medium in the return pipe 230. Specifically, the first medium and the second medium exchange heat within the second heat exchanger 330, allowing the second medium to absorb heat in the second heat exchange channel 332 before entering the heating channel 320 to heat the phase change material, causing the phase change material to absorb heat and undergo a phase change.

[0046] Furthermore, the battery cooling unit also includes a first circulation pump 240 and a three-way valve 250. The first circulation pump 240 is installed on the liquid supply pipe 220, and its inlet is connected to the heat exchange outlet of the first heat exchanger 210. The inlet and first outlet of the three-way valve 250 are both connected to the return pipe 230, and its first outlet is connected to the heat exchange inlet of the first heat exchanger 210. The second outlet of the three-way valve 250 is connected to the inlet of the first circulation pump 240 via a branch pipe 260. The heat storage unit also includes a two-way valve 340, a second circulation pump 350, and a third circulation pump (not shown in the figure). The inlet of the two-way valve 340 is connected to the first outlet of the three-way valve 250, and its outlet is connected to the inlet of the second circulation pump 350. The outlet of the second circulation pump 350 is connected to the inlet of the first heat exchange channel 331, and its outlet is connected to the inlet of the three-way valve 250. The inlet of the second heat exchange channel 332 is connected to the outlet of the heating channel 320, and the outlet of the second heat exchange channel 332 is connected to the inlet of the heating channel 320 through the third circulating pump.

[0047] By opening the two-way valve 340, the second circulation pump 350, and the third circulation pump, the high-temperature first medium in the return pipe 230 enters the first heat exchange channel 331, allowing the first medium to heat the second medium in the second heat exchanger 330, and then allowing the second medium to enter the heating channel 320 to heat the phase change material. Figure 3 As shown, when the two-way valve 340, the second circulation pump 350, and the third circulation pump are open, the flow path of the first medium is shown by the solid arrow in the figure, and the flow path of the second medium is shown by the hollow arrow in the figure. When it is no longer necessary to heat the phase change material (for example, when the temperature of the first medium in the return pipe 230 is lower than the temperature of the phase change material), the two-way valve 340, the second circulation pump 350, and the third circulation pump are closed. The phase change material no longer absorbs heat but undergoes natural cooling, releasing heat during its natural cooling process to heat the battery 10, so that the battery 10 can be maintained within a suitable temperature range (for example, above 0°C) even in low-temperature environments. Figure 2 As shown, after closing the two-way valve 340, the second circulation pump 350 and the third circulation pump, the first medium no longer flows between the first heat exchange channel 331 and the return pipe 230, and the second medium no longer flows between the second heat exchange channel 332 and the heating channel 320.

[0048] In another embodiment, the second medium can circulate between the heating channel 320 and the return pipe 230, so that the high-temperature first medium in the return pipe 230 directly enters the heating channel 320 to heat the phase change material.

[0049] Optionally, a heating tube is provided within the interlayer 130, and the internal flow space of the heating tube is the aforementioned heating channel 320. In another embodiment, the heating channel 320 is located on the side of the inner shell 110 facing the interlayer 130.

[0050] This embodiment also provides a vehicle that includes the above-described battery thermal management system, so that the vehicle can use the waste heat of the battery cooling unit to heat the battery 10.

[0051] This embodiment also provides a thermal management method for controlling the battery thermal management system described above. This method can utilize the residual heat of the battery cooling unit to heat the battery 10 that has stopped supplying power, so that the battery 10 that has stopped supplying power can be maintained at a more suitable temperature, avoiding damage to the battery 10 that has stopped supplying power in a low-temperature environment. In addition, when the battery 10 that has stopped supplying power starts supplying power again, this method can enable the battery 10 to quickly resume supplying power.

[0052] Specifically, such as Figure 4 As shown, the thermal management method includes: after the battery 10 stops supplying power, detecting T1 and T2, where T1 is the temperature of the first medium in the return pipe 230, and T2 is the temperature of the phase change material or the temperature of the battery 10. If T1 > T2 > T3, the phase change material absorbs heat from the first medium in the return pipe 230, and T3 is the phase change temperature of the phase change material. T1 and T2 are continuously detected. When T1 < T2, or when T1 < T3, the phase change material stops absorbing heat from the first medium in the return pipe 230.

[0053] Based on the above design, after battery 10 stops supplying power, when T1 > T2 > T3, the phase change material absorbs the heat from the first medium in the return pipe 230 and undergoes a phase change to recover and store the waste heat that should have been dissipated into the environment through the first heat exchanger 210 in the phase change material. During this process, T1 and T2 are continuously monitored. As the phase change material continuously absorbs the heat from the first medium in the return pipe 230, the temperature of the first medium gradually decreases. When T1 < T2, or when T1 < T3, the heat from the first medium in the return pipe 230 is insufficient to heat the phase change material, at which point the phase change material stops absorbing the heat from the first medium in the return pipe 230. After the phase change material stops absorbing heat, it gradually releases a large amount of latent heat to the battery 10 and undergoes another phase change, thereby achieving the effect of heating the battery 10. This allows the battery 10, which has stopped supplying power, to maintain a relatively suitable temperature (e.g., above 0°C) in a low-temperature environment. When the battery 10 resumes supplying power, it can prevent damage to the battery 10 due to excessively low temperatures and enable the battery 10 to quickly resume supplying power in a low-temperature environment, while also extending the battery 10's lifespan and improving the user experience. On the other hand, in this thermal management method, the phase change material absorbs the waste heat that would otherwise be dissipated into the environment through the first heat exchanger 210, which has the effect of reducing energy consumption.

[0054] It should be noted that T2 can be the average temperature of the phase change material or the temperature of the phase change material at a certain location within the interlayer 130. In this embodiment, T2 is the average temperature of the phase change material. In other embodiments, T2 can also be the temperature of the phase change material at a certain location within the interlayer 130, or the temperature of the battery 10.

[0055] Furthermore, if T1 ≥ T2 + ΔT > T3, then the phase change material absorbs heat from the first medium in the return pipe 230, where ΔT is the second preset temperature. In other words, the phase change material only absorbs heat from the first medium in the return pipe 230 when the temperature of the first medium in the return pipe 230 exceeds T2 by a certain value. This method ensures that the phase change material absorbs sufficient heat from the first medium, which is beneficial for increasing the heat storage capacity of the phase change material. This not only improves the heating effect on the battery 10 but also increases the waste heat utilization rate, thereby further reducing energy consumption.

[0056] Furthermore, 3℃≤ΔT≤12℃, for example, ΔT can be 3℃, 5℃, 8℃, 10℃ or 12℃, etc.

[0057] Optionally, after battery 10 stops supplying power, when power is needed from battery 10, T2 is detected. If T2 ≥ T4, battery 10 starts supplying power, where T4 is a first preset temperature, greater than or equal to 0℃. For example, T4 could be 0℃, 3℃, 5℃, or 6.5℃. If T2 < T4, an auxiliary heating unit heats battery 10. After battery 10 stops supplying power, the phase change material uses the recovered and stored waste heat to heat battery 10, allowing battery 10 to maintain above 0℃ in a low-temperature environment for a period of time. When the phase change material has transferred all the stored heat to battery 10, it can no longer heat battery 10. At this time, the outer shell 120 and the solidified phase change material provide insulation for battery 10, causing battery 10 to cool down at an extremely slow rate. When battery 10 needs to supply power again, T2 is detected first, and T2 and T4 are compared. When T2 ≥ T4, it is assumed that there is no risk of internal icing in battery 10. In this case, battery 10 skips the cold start preheating procedure and starts supplying power directly. This avoids damage to battery 10 due to low-temperature cold start and saves preheating time. If battery 10 is not supplying power in a low-temperature environment for a long time, its temperature will gradually drop below 0°C. In this case, T2 < T4. Therefore, when T2 < T4, it is assumed that there is a risk of internal icing in battery 10. In this case, battery 10 enters the cold start preheating procedure, where the auxiliary heating unit heats battery 10 to prevent damage from low-temperature cold start. Thus, this method, while achieving "zero waiting time" for battery 10 to resume power supply, further reduces the risk of damage to battery 10 due to low-temperature cold start.

[0058] In practical applications, the risk of battery 10 being damaged by cold starts due to low temperatures can be further reduced by increasing T4. For example, compared to T4 being 0°C, the risk of battery 10 being damaged by cold starts due to low temperatures is lower when T4 is 5°C. Furthermore, when T4 is greater than 0°C and T2 < T4, although battery 10 first enters the cold start preheating program (i.e., the auxiliary heating unit heats battery 10) before starting to supply power, the preheating time of battery 10 can be shortened because the temperature of battery 10 is greater than 0°C when preheating begins, so that battery 10 only needs a very short preheating time to start supplying power.

[0059] It should be noted that the specific method of the cold start preheating procedure for the battery 10, which involves the auxiliary heating unit heating the battery 10, is existing technology in the field. For example, a solid hydrogen storage material can react with hydrogen to release heat, which is then absorbed by circulating water and used to heat the battery 10 through a heat exchanger. Alternatively, a gas heater can be added to directly heat the coolant cooling the battery 10 by burning hydrogen. Another option is to use a PTC heater to heat the battery 10, etc., which will not be listed here.

[0060] Optionally, when the battery 10 stops supplying power, the circulation of the first medium between the supply pipe 220, the return pipe 230, and the cooling channel is stopped. That is, when the battery 10 stops supplying power, the battery cooling unit stops cooling the battery 10 to slow down the cooling rate of the battery 10 and avoid affecting the heating effect of the phase change material on the battery 10.

[0061] The following section uses a vehicle employing the aforementioned battery thermal management system and thermal management method as an example to briefly explain the battery thermal management system and thermal management method.

[0062] like Figures 1 to 4 As shown, when the vehicle is turned off and the battery 10 stops supplying power, the first circulation pump 240 is turned off, the circulation of the first medium between the supply pipe 220, the return pipe 230 and the cooling channel is stopped, and the battery cooling unit stops cooling the battery 10.

[0063] Detecting T1 and T2, if T1 ≥ T2 + ΔT > T3, then the waste heat from the battery cooling unit can be recovered and reused. At this time, the system enters the heat storage mode. Figure 3 As shown, the two-way valve 340, the second circulation pump 350 and the third circulation pump are opened, and the inlet and the first outlet of the three-way valve 250 are connected, so that the second medium absorbs the heat of the first medium in the second heat exchanger 330, and the paraffin absorbs the heat of the second medium in the heating channel 320. The paraffin heats up and begins to melt, and stores latent heat.

[0064] In the heat storage mode, T1 and T2 are continuously monitored. When the temperature T1 of the first medium drops below T2, the heat from the first medium in the return pipe 230 is no longer sufficient to heat the paraffin. At this point, the heat storage mode stops, and the system enters the free heat dissipation mode. Figure 2 As shown, the two-way valve 340, the second circulation pump 350, and the third circulation pump are closed. At this point, the paraffin wax no longer absorbs heat and begins to gradually solidify from a liquid state. During the solidification process, the paraffin wax releases a large amount of latent heat, maintaining the temperature of the battery 10 in the inner shell 110 at a relatively high level. When the paraffin wax is completely solidified, its thermal conductivity decreases significantly. The solid paraffin wax and the outer shell 120 form a double-layer insulation structure, slowing down the heat loss of the battery 10 to the external environment, allowing the battery 10 in the inner shell 110 to cool down at an extremely slow rate.

[0065] When the vehicle is powered on again, T2 is checked. If T2 ≥ T4, it is assumed that there is no risk of ice formation inside battery 10, and battery 10 skips all cold start preheating procedures and directly enters normal operating mode to start supplying power. If T2 < T4, the normal cold start preheating procedure is entered to preheat battery 10.

[0066] Vehicles employing the aforementioned battery thermal management system and method recover and reuse waste heat from the battery cooling unit via paraffin wax, allowing the battery 10 to maintain an above-zero temperature even after prolonged periods of power outage. This fundamentally avoids the performance degradation associated with cold starts at sub-zero temperatures, significantly slowing down the mechanical degradation of the battery 10 and potentially extending its lifespan by over 30% in cold regions. Furthermore, in most vehicle parking scenarios (e.g., overnight at -20°C), the battery 10 can be powered on again the following day without any preheating time, achieving "power on and go," completely alleviating users' anxiety about slow low-temperature starts in electric vehicles. Moreover, in the aforementioned battery thermal management system and method, the paraffin wax recovers waste heat that would otherwise be dissipated into the environment through the first heat exchanger 210. The entire waste heat recovery and reuse process, excluding the battery cooling unit and the third circulation pump, consumes no additional energy. Compared to traditional active heating solutions, this saves 0.5kWh-2kWh of energy per vehicle start-up. Finally, the aforementioned battery thermal management system integrates the heat storage, heating, and insulation functions primarily within the housing unit 100 that houses the battery 10. The system has a high degree of integration, eliminating the need for additional external heat storage tanks or other structures. The overall structure is simple and compact, making it suitable for vehicle spaces with limited space. Furthermore, the phase change materials such as paraffin are inexpensive and easy to engineer.

[0067] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A battery thermal management system, characterized in that, include: A housing unit (100) includes an inner shell (110) and an outer shell (120). The inner shell (110) is used to accommodate a battery (10). The battery (10) is provided with cooling channels. The inner shell (110) is a heat-conducting component and is located inside the outer shell (120). A sandwich layer (130) is provided between the inner shell (110) and the outer shell (120). A battery cooling unit, the battery cooling unit includes a first heat exchanger (210), the first heat exchanger (210) is connected to the cooling channel through a liquid supply pipe (220) and a liquid return pipe (230), and a first medium can flow in the liquid supply pipe (220), the liquid return pipe (230) and the cooling channel; A heat storage unit, the heat storage unit includes a phase change material, the phase change material is disposed in the interlayer (130), the phase change material can absorb the heat of the first medium in the return pipe (230), and the phase change material can heat the battery (10).

2. The battery thermal management system according to claim 1, characterized in that, The interlayer (130) is provided with a reserved expansion space (131).

3. The battery thermal management system according to claim 2, characterized in that, The phase change material is a solid-liquid phase change material, and the reserved expansion space (131) is located at least at the bottom of the interlayer (130). An expansion absorption element (140) is provided in the reserved expansion space (131).

4. The battery thermal management system according to any one of claims 1-3, characterized in that, The phase change material is a solid-liquid phase change material, and the phase change material has heat insulation capabilities when it is in a solid state. And / or, the housing (120) is a heat insulation component.

5. The battery thermal management system according to any one of claims 1-3, characterized in that, The heat storage unit also includes a heat-conducting element (310), which is disposed within the interlayer (130).

6. The battery thermal management system according to any one of claims 1-3, characterized in that, The heat storage unit further includes a heating channel (320) and a second medium, wherein the heating channel (320) is located within the interlayer (130); The heat storage unit also includes a second heat exchanger (330), which is provided with a first heat exchange channel (331) and a second heat exchange channel (332). The first medium can circulate between the first heat exchange channel (331) and the return pipe (230), and the second medium can circulate between the second heat exchange channel (332) and the heating channel (320). Alternatively, the second medium can circulate between the heating channel (320) and the return pipe (230).

7. A vehicle, characterized in that, Includes the battery thermal management system as described in any one of claims 1-6.

8. A thermal management method, characterized in that, A method for controlling the battery thermal management system according to any one of claims 1-6, the thermal management method comprising: After the battery (10) stops supplying power, T1 and T2 are detected. T1 is the temperature of the first medium in the return pipe (230), and T2 is the temperature of the phase change material or the temperature of the battery (10). If T1 > T2 > T3, then the phase change material absorbs the heat of the first medium in the return pipe (230), and T3 is the phase change temperature of the phase change material; Continuous monitoring of T1 and T2; When T1 < T2, or when T1 < T3, the phase change material stops absorbing heat from the first medium in the return pipe (230).

9. The thermal management method according to claim 8, characterized in that, After the battery (10) stops supplying power, when the battery (10) needs to supply power, T2 is detected; If T2≥T4, then the battery (10) starts to supply power, where T4 is the first preset temperature, which is greater than or equal to 0℃; If T2 < T4, then the auxiliary heating unit heats the battery (10).

10. The thermal management method according to claim 8, characterized in that, When the battery (10) stops supplying power, the circulation of the first medium between the liquid supply pipe (220), the liquid return pipe (230), and the cooling channel is stopped.

Images