High-capacity battery thermal load management system based on composite cold plate

Abstract

The invention relates to a high-capacity battery thermal load management system based on a composite cold plate, which comprises a refrigerant loop, a silicone oil loop and a cooling liquid loop, a battery pack is immersed in silicone oil, a protective cover is provided with a silicone oil inlet and a silicone oil outlet, and the cooling liquid loop is used for heating the battery pack. The refrigerant loop, the silicone oil loop and the cooling liquid loop are matched to form a plurality of operation modes, and the battery pack is refrigerated or heated according to the thermal load of the battery pack. The battery cooling and heating effect and the temperature uniformity of the liquid cooling mode can be improved, the battery can be cooled or heated through the heat pump system, the system mode is switched according to the designed battery thermal load confirmation method, and the system performance and the energy consumption are both considered.

Description

Technical Field

[0001] The present invention relates to the technical field of battery thermal management, and in particular to a large-capacity battery thermal load management system based on a composite cold plate. Background Art

[0002] Large-capacity batteries are often used in electric vehicles and energy storage fields, and battery temperature greatly affects the battery's charging and discharging performance and safety. For example, when charging and discharging at a high rate in a high-temperature environment in the summer, the battery generates a lot of heat and the temperature is high, which can easily cause the battery life to decrease or even cause thermal runaway and fire. In the low-temperature environment in winter, the battery temperature is low, which will cause the battery's charging and discharging capacity to decrease. Therefore, the thermal load of the high-rate battery must be thermally managed to reach a suitable operating temperature.

[0003] Existing technologies usually use liquid cooling or direct cooling to manage battery temperature. In traditional liquid cooling systems, due to the small temperature difference between the heat exchange between the battery and the coolant, the heat of the battery is difficult to be absorbed by the coolant, which causes the battery temperature to continue to rise. At the same time, it will also cause the temperature of the battery close to the coolant inlet to be low, while the temperature of the battery far from the coolant inlet is high, resulting in uneven temperature between batteries and difficulty in unified management. Although the direct cooling system has a good heat dissipation effect and can significantly reduce the battery temperature and ensure the thermal safety of the battery, it is also easy to cause uneven battery temperature, and the thermal load of the battery is low or medium most of the time. At this time, using a direct cooling system will cause excessive energy consumption. Summary of the invention

[0005] In view of the defects of the prior art, the present invention provides a large-capacity battery thermal load management system based on a composite cold plate.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a large-capacity battery heat load management system based on a composite cold plate, including a refrigerant circuit, a silicone oil circuit, a coolant circuit and a dual-channel battery cold plate, the refrigerant circuit is used to heat or cool the battery pack, the battery silicone oil circuit is used to heat or cool the battery pack; the coolant circuit is used to heat the battery pack, and the refrigerant circuit, the silicone oil circuit and the coolant circuit cooperate to form several operating modes to achieve cooling or heating of the battery pack; The battery pack is arranged at the upper end of the dual-channel battery cold plate. A protective cover wrapping the battery pack is arranged at the upper end of the dual-channel battery cold plate. The protective cover is filled with silicone oil, and the battery pack is immersed in the silicone oil. The refrigerant circuit includes a compressor, a four-way reversing valve, an external heat exchanger, an electronic expansion valve, a refrigerant channel of a dual-channel battery cold plate, a stop valve and a gas-liquid separator, and each component is connected by a pipeline; The silicone oil circuit includes a first electronic water pump, a first three-way valve, a protective cover, a silicone oil channel of a dual-channel battery cold plate, a second three-way valve, a radiator, a silicone oil heat exchange channel of a plate heat exchanger and a first compensation water tank, and each component is connected by a pipeline; The coolant circuit includes a second electronic water pump, a PTC electric heater, a coolant heat exchange channel of a plate heat exchanger and a second compensation water tank. The components are connected by pipelines, and the battery pack can be cooled or heated by switching the valves.

[0007] As a preferred solution, it includes a front cabin, in which the external heat exchanger and the radiator are both arranged, and a fan is installed in the front of the external heat exchanger.

[0008] As a preferred solution, the protective cover has a silicone oil inlet and a silicone oil outlet, the output end of the compressor is connected to the first end of the four-way reversing valve, the third end of the four-way reversing valve is connected to the input end of the compressor through a gas-liquid separator, the second end of the four-way reversing valve is connected to the external heat exchanger, the external heat exchanger is connected to the refrigerant channel of the dual-channel battery cold plate through an electronic expansion valve, the refrigerant channel of the dual-channel battery cold plate is connected to the fourth end of the four-way reversing valve through a stop valve; the output end of the first electronic water pump is connected to the first end of the first three-way valve, the second end of the first three-way valve is connected to the second three-way valve through the silicone oil channel of the dual-channel battery cold plate The first port of the valve is connected, the third end of the first three-way valve is connected to the silicone oil inlet of the protective cover, the silicone oil outlet of the protective cover is connected to the first end of the second three-way valve, the second end of the second three-way valve is connected to the radiator, the third end of the second three-way valve is connected to the silicone oil heat exchange channel of the plate heat exchanger, the radiator and the silicone oil heat exchange channel of the plate heat exchanger are connected to the input end of the first electronic water pump through the first compensation water tank; the output end of the second electronic water pump is connected to the coolant channel of the plate heat exchanger through the PTC electric heater, and the coolant channel of the plate heat exchanger is connected to the input end of the second electronic water pump through the second compensation water tank.

[0009] As a preferred solution, the operation modes of the thermal management system include the following five: Battery pack low load cooling mode; Battery pack medium load cooling mode; Battery pack high load cooling mode; Battery pack extremely low temperature heating mode; Battery pack low temperature heating mode.

[0010] As a preferred solution, in the low-load cooling mode of the battery pack, the electronic expansion valve and the stop valve are closed; the output end of the first electronic water pump is connected to the first end of the first three-way valve, the second end of the first three-way valve is connected to the silicone oil channel of the dual-channel battery cold plate, the silicone oil channel of the dual-channel battery cold plate is connected to the first end of the second three-way valve, the second end of the second three-way valve is connected to the radiator, the radiator is connected to the first compensation water tank, and the first compensation water tank is connected to the input end of the first electronic water pump.

[0011] As a preferred solution, in the load cooling mode of the battery pack, the electronic expansion valve and the stop valve are closed; the output end of the first electronic water pump is connected to the first end of the first three-way valve, the second end of the first three-way valve is connected to the silicone oil channel of the dual-channel battery cold plate, the third end of the first three-way valve is connected to the silicone oil inlet of the protective cover, the silicone oil channel of the dual-channel battery cold plate and the silicone oil outlet of the protective cover are both connected to the first end of the second three-way valve, the second end of the second three-way valve is connected to the radiator, the radiator is connected to the first compensation water tank, and the first compensation water tank is connected to the input end of the first electronic water pump.

[0012] As a preferred solution, in the high-load refrigeration mode of the battery pack, the electronic expansion valve and the stop valve are opened, the output end of the compressor is connected to the first end of the four-way reversing valve, the third end of the four-way reversing valve is connected to the input end of the compressor through a gas-liquid separator, the second end of the four-way reversing valve is connected to an external heat exchanger, the external heat exchanger is connected to the refrigerant channel of the dual-channel battery cold plate through the electronic expansion valve, the refrigerant channel of the dual-channel battery cold plate is connected to the stop valve, and the stop valve is connected to the fourth end of the four-way reversing valve; the output end of the first electronic water pump is connected to the first end of the first three-way valve, the third end of the first three-way valve is connected to the protective cover, the protective cover is connected to the first end of the second three-way valve, the third end of the second three-way valve is connected to the silicone oil heat exchange channel of the plate heat exchanger, the silicone oil heat exchange channel of the plate heat exchanger is connected to the first compensation water tank, and the first compensation water tank is connected to the input end of the first electronic water pump.

[0013] As a preferred solution, in the extremely low temperature heating mode of the battery pack, the electronic expansion valve and the stop valve are closed; the output end of the first electronic water pump is connected to the first end of the first three-way valve, the second end of the first three-way valve is connected to the silicone oil channel of the dual-channel battery cold plate, the third end of the first three-way valve is connected to the silicone oil inlet of the protective cover, the silicone oil channel of the dual-channel battery cold plate and the silicone oil outlet of the protective cover are both connected to the first end of the second three-way valve, the second end of the second three-way valve is connected to the silicone oil heat exchange channel of the plate heat exchanger, the silicone oil heat exchange channel of the plate heat exchanger is connected to the first compensation water tank, and the first compensation water tank is connected to the input end of the first electronic water pump; the output end of the second electronic water pump is connected to the PTC electric heater, the PTC electric heater is connected to the coolant heat exchange channel of the plate heat exchanger, the coolant heat exchange channel of the plate heat exchanger is connected to the second compensation water tank, and the second compensation water tank is connected to the input end of the second electronic water pump.

[0014] As a preferred solution, in the low-temperature heating mode of the battery pack, the electronic expansion valve and the stop valve are opened, the output end of the compressor is connected to the first end of the four-way reversing valve, the third end of the four-way reversing valve is connected to the input end of the compressor through a gas-liquid separator, the second end of the four-way reversing valve is connected to the external heat exchanger, the external heat exchanger is connected to the refrigerant channel of the dual-channel battery cold plate through the electronic expansion valve, the refrigerant channel of the dual-channel battery cold plate is connected to the stop valve, and the stop valve is connected to the fourth end of the four-way reversing valve; the output end of the first electronic water pump is connected to the first end of the first three-way valve, the second end of the first three-way valve is connected to the silicone oil channel of the dual-channel battery cold plate, the third end of the first three-way valve is connected to the silicone oil inlet of the protective cover, the silicone oil channel of the dual-channel battery cold plate and the silicone oil outlet of the protective cover are both connected to the first end of the second three-way valve, the second end of the second three-way valve is connected to the silicone oil heat exchange channel of the plate heat exchanger, the silicone oil heat exchange channel of the plate heat exchanger is connected to the first compensation water tank, and the first compensation water tank is connected to the input end of the first electronic water pump.

[0015] The beneficial effects of the present application are as follows: 1. When the battery pack needs to be heated in a low-temperature environment, the present application can use a heat pump direct heating method to reduce energy consumption. In an extremely low-temperature environment, the heat pump efficiency is low, and the PTC electric heater can also be turned on to quickly heat up the battery pack; when the cooling load of the battery pack is low, based on the dual-channel battery cold plate, the liquid cooling heat dissipation capacity of the battery pack can be improved, and when the cooling load of the battery pack is high, a heat pump system is used to quickly cool the battery pack. Due to the strong cooling capacity of the heat pump system, the dual-channel battery cold plate is in contact with the silicone oil and the bottom of the battery pack. The silicone oil can ensure that the temperature of the bottom and surrounding areas of the battery pack is consistent, and once the battery pack catches fire out of control due to other factors, the silicone oil can prevent the fire from spreading.

[0016] 2. This application designs a simple and reasonable large-capacity battery thermal management system architecture, provides a variety of working modes, covers low, medium and high cooling loads and extremely low temperature heating scenarios of large-capacity batteries, and can reduce the energy consumption of the thermal management system while ensuring the thermal requirements of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a front cross-sectional view of a dual-channel battery cold plate of the present invention;

[0018] Figure 2 The channel structure diagram of the dual-channel battery cold plate of the present invention

[0019] Figure 3 It is a schematic diagram of the structural principle of the present invention;

[0020] Figure 4 It is a schematic diagram of the thermal load management mode of the battery pack of the present invention;

[0021] Figure 5 Schematic diagram of the low-load cooling mode of the battery pack of the present invention;

[0022] Figure 6 A schematic diagram of a load cooling mode in a battery pack of the present invention;

[0023] Figure 7 Schematic diagram of the high-load cooling mode of the battery pack of the present invention;

[0024] Figure 8 Schematic diagram of the extremely low temperature heating mode of the battery pack of the present invention;

[0025] Fig. 9 Schematic diagram of the low-temperature heating mode of the battery pack of the present invention.

[0026] 10. The PCB board is provided with a plurality of modules, each of which is provided with a plurality of modules, and each of which is provided with a plurality of modules. The PCB board is provided with a plurality of modules, each of which is provided with a plurality of modules. The PCB board is provided with a plurality of modules, each of which is provided with a plurality of modules. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that in the description of the present invention, unless otherwise specified, the meaning of "multiple" is two or more; the orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0028] See also Figure 1-9The embodiment of the present invention provides a large-capacity battery heat load management system based on a composite cold plate, including a refrigerant circuit, a silicone oil circuit, a coolant circuit and a dual-channel battery cold plate 5, wherein the refrigerant circuit is used to heat or cool a battery pack 102, and the battery silicone oil circuit is used to heat or cool the battery pack 102; the coolant circuit is used to heat the battery pack 102, and the refrigerant circuit, the silicone oil circuit and the coolant circuit cooperate to form a plurality of operation modes to realize cooling or heating the battery pack 102; the battery pack 102 is arranged at the upper end of the dual-channel battery cold plate 5, and a protective cover 4 is provided on the upper end of the dual-channel battery cold plate 5 to wrap the battery pack 102, and the protective cover 4 is filled with silicone oil 108, and the battery pack 102 is immersed in the silicone oil 108; the refrigerant circuit pack The circuit includes a compressor 2, a four-way reversing valve 1, an external heat exchanger 18, an electronic expansion valve 16, a refrigerant channel 105 of a dual-channel battery cold plate 5, a stop valve 6 and a gas-liquid separator 3, and each component is connected by a pipeline; the silicone oil circuit includes a first electronic water pump 14, a first three-way valve 15, a protective cover 4, a silicone oil channel 107 of a dual-channel battery cold plate 5, a second three-way valve 7, a radiator 12, a silicone oil heat exchange channel of a plate heat exchanger 11 and a first compensation water tank 13, and each component is connected by a pipeline; the coolant circuit includes a second electronic water pump 9, a PTC electric heater 8, a coolant heat exchange channel of a plate heat exchanger 11 and a second compensation water tank 10, and each component is connected by a pipeline, and each valve is switched to achieve cooling or heating of the battery pack 102.

[0029] A water-glycol mixture is used as the coolant in the coolant circuit. The front cabin is comprised of an external heat exchanger 18 and a radiator 12, and a fan 17 is provided at the front of the external heat exchanger 18.

[0030] Combination Figure 1-2As shown, a thermal pad 103 is attached to the upper surface of the dual-channel battery cold plate 5, and the dual-channel battery cold plate 5 includes a cold plate body 104. The thermal pad 103 is attached to the battery pack 102, and the upper end of the battery pack 102 is provided with a pole ear 101. The battery pack 102 is immersed in silicone oil 108. The protective cover 4 seals the silicone oil 108 and the battery pack 102. The protective cover 4 has a silicone oil inlet 110 and a silicone oil outlet 111, which are respectively connected to the third end of the first three-way valve 15 and the first end of the second three-way valve 7. The refrigerant channel 105 and the silicone oil channel 107 are both arranged in the cold plate body 104, and the refrigerant channel 105 is located at the upper part of the silicone oil channel 107. The refrigerant of the heat pump system can be in the refrigerant channel 110. 05, silicone oil 108 can flow in the silicone oil channel 107, the refrigerant channel 105 includes two refrigerant branches symmetrically arranged in the cold plate body 104, the two refrigerant branches are symmetrically arranged along the length direction of the cold plate body 104, the refrigerant branch is S-shaped, the longitudinal section of the refrigerant branch is rectangular, and a liquid absorbent core 105 is provided on the left and right sides of the inner wall of the refrigerant branch. The refrigerant branch has a first channel inlet 1001 and a first channel outlet 1002. The two first channel inlets 1001 are connected and merged to form a refrigerant inlet of the refrigerant channel 105, and the two first channel outlets 1002 are connected and merged to form a refrigerant outlet of the refrigerant channel 105. The refrigerant inlet is connected to the electronic expansion valve 16 through a pipeline, and the refrigerant outlet is connected to the stop valve 6.

[0031] The silicone oil channel 107 includes two silicone oil branches symmetrically arranged in the cold plate body 104, the two silicone oil branches are symmetrically arranged along the length direction of the cold plate body 104, the silicone oil branches are S-shaped, and the longitudinal section of the silicone oil branch is rectangular. The silicone oil branch has a second channel inlet and a second channel outlet. The two second channel inlets are connected and merged to form the silicone oil channel inlet of the silicone oil channel 107, and the two second channel outlets are connected and merged to form the silicone oil channel outlet of the silicone oil channel 107. The silicone oil channel inlet is connected to the second end of the first three-way valve 15 through a pipeline, and the silicone oil channel outlet is connected to the first end of the second three-way valve 7 through a pipeline. Region b and region c in the cold plate body 104 are defined as high temperature regions, and region a is defined as a low temperature region.

[0032] See also Figure 1-Figure 3In the liquid cooling scenario of the battery pack 102, the dual-channel battery cold plate 5 has silicone oil flowing in the silicone oil channel 107, the electronic expansion valve 16 at one end of the refrigerant channel 105 is closed, and the stop valve 6 at the other end is closed, and the refrigerant channel 105 forms a closed space, which is filled with refrigerant; in the vertical direction of the refrigerant channel 105, the heat of the battery pack 102 is transferred to the upper part of the dual-channel battery cold plate 5 through the thermal pad 103. Since the temperature of the upper part of the cold plate body 104 is high and the temperature of the lower part is low at this time, the refrigerant in the refrigerant channel 105 is in the refrigerant channel 1 After condensation on the lower surface of the refrigerant 105, the heat released is absorbed by the silicone oil in the silicone oil channel 106 and dissipated into the environment through the radiator 12. The condensed refrigerant reaches the upper surface of the refrigerant channel 105 under the action of the capillary force in the liquid absorbent core 105, absorbs the heat from the upper part of the cold plate body 104, and is vaporized. At this time, the pressure near the upper surface of the refrigerant channel 105 increases. Driven by the pressure difference between the upper and lower parts of the channel, the vaporized refrigerant moves to the lower surface of the refrigerant channel 105 to complete the next condensation. This reciprocating cycle realizes efficient heat dissipation of the battery pack 102.

[0033] At the same time, in the horizontal direction of the refrigerant channel 105, the temperature of the battery pack 102 in the b area and the c area is high, and the temperature of the battery pack 102 in the a area is relatively low. Since the higher the gas temperature, the greater the pressure, a pressure difference is formed between the high temperature area and the low temperature area of ​​the battery pack 102 in the refrigerant channel 105. This pressure difference causes the high temperature refrigerant in the refrigerant channel 105 in the high temperature area b and the c area to move to the low temperature area a, releasing heat to the low temperature area. Similarly, if there is a temperature difference between the b area and the c area, the heat in the high temperature area of ​​the cold plate 104 will be released to the low temperature area, making the temperature of the cold plate body 104 uniform, so that the battery pack 102 in the high temperature area transfers heat to the battery pack 102 in the low temperature area, and the temperature uniformity of the battery pack 102 is achieved. Since the battery pack 102 is immersed in the silicone oil 108, the battery pack 102 and the silicone oil 108 are sealed by the protective cover 4, so that the temperature of the entire battery pack 102 is more uniform, and if the battery pack 102 has thermal runaway and catches fire, the silicone oil 108 can prevent the fire from spreading.

[0034] Specifically, the present application sets up a dual-channel battery cold plate 5, utilizes the phase change of the refrigerant to enhance the heat transfer capacity between the battery pack 102 and the silicone oil 108, improves the heat dissipation performance of the liquid cooling system, reduces the use of the direct cooling system and thus reduces energy consumption, and can also use the heat pump system direct cooling method to quickly reduce the temperature of the battery pack 102 under high temperature conditions to ensure the safety of the battery pack 102. While meeting the basic temperature requirements of the battery pack 102 such as heating and cooling, the internal structure of the dual-channel battery cold plate 5 can also enable the high-temperature battery pack 102 to transfer heat to the low-temperature battery pack 102, greatly improving the overall temperature uniformity of the battery pack 102 and facilitating the unified management of the entire battery pack 102.

[0035] Combination Figure 3 As shown, the output end of the compressor 2 is connected to the first end of the four-way reversing valve 1, the third end of the four-way reversing valve 1 is connected to the input end of the compressor 2 through the gas-liquid separator 3, the second end of the four-way reversing valve 1 is connected to the external heat exchanger 18, the external heat exchanger 18 is connected to the refrigerant channel 105 of the dual-channel battery cold plate 5 through the electronic expansion valve 16, the refrigerant channel 105 of the dual-channel battery cold plate 5 is connected to the fourth end of the four-way reversing valve 1 through the stop valve 6; the output end of the first electronic water pump 14 is connected to the first end of the first three-way valve 15, the second end of the first three-way valve 15 is connected to the first port of the second three-way valve 7 through the silicone oil channel 107 of the dual-channel battery cold plate 5, and the first three-way valve 15 is connected to the first end of the second three-way valve 7 through the silicone oil channel 107 of the dual-channel battery cold plate 5. The third end of the valve 15 is connected to the silicone oil inlet 110 of the protective cover 4, the silicone oil outlet 111 of the protective cover 4 is connected to the first end of the second three-way valve 7, the second end of the second three-way valve 7 is connected to the radiator 12, the third end of the second three-way valve 7 is connected to the silicone oil heat exchange channel of the plate heat exchanger 11, the radiator 12 and the silicone oil heat exchange channel of the plate heat exchanger 11 are connected to the input end of the first electronic water pump 14 through the first compensation water tank 13; the output end of the second electronic water pump 9 is connected to the coolant heat exchange channel of the plate heat exchanger 11 through the PTC electric heater 8, and the coolant heat exchange channel of the plate heat exchanger 11 is connected to the input end of the second compensation water tank 10 through the second compensation water tank 10.

[0036] Specifically, the first end, second end, third end and fourth end of the four-way reversing valve 1 correspond to port A, port B, port C and port D respectively, the first end, second end and third end of the first three-way valve 15 correspond to port E, port F and port G respectively, and the first end, second end and third end of the second three-way valve 7 correspond to port H, port I and port J respectively.

[0037] The operating modes of the thermal management system include the following five: battery pack low load cooling mode; battery pack medium load cooling mode; battery pack high load cooling mode; battery pack extremely low temperature heating mode; battery pack low temperature heating mode.

[0038] Combination Figure 5 As shown, when the ambient temperature T e >15℃ or battery pack temperature T b >30℃, and the battery temperature T bWhen the temperature is ≤ 35°C and the battery pack heat load a ≤ 0, the thermal management system of the present application is in the low-load refrigeration mode of the battery pack. When the thermal management system is in the low-load refrigeration mode of the battery pack 102, since the heat load of the battery pack 102 is small and rapid heat dissipation is not required, the electronic expansion valve 16 and the stop valve 6 are closed; the output end of the first electronic water pump 14 is connected to the first end of the first three-way valve 15, the second end of the first three-way valve 15 is connected to the silicone oil channel 107 of the dual-channel battery cold plate 5, the silicone oil channel 107 of the dual-channel battery cold plate 5 is connected to the first end of the second three-way valve 7, the second end of the second three-way valve 7 is connected to the radiator 12, the radiator 12 is connected to the first compensation water tank 13, and the first compensation water tank 13 is connected to the input end of the first electronic water pump 14.

[0039] Silicone oil circuit: The first electronic water pump 14 drives the silicone oil 108 to flow through the E port and F port of the first three-way valve 15 and then into the silicone oil channel 107 at the lower part of the dual-channel battery cold plate 5. After the silicone oil 108 absorbs the heat of the battery 102, it flows into the radiator 12 through the H port and I port of the second three-way valve 7, exchanges heat with the external environment in the radiator 12, and dissipates the heat of the battery pack 102 absorbed into the environment. The silicone oil 108 in the protective cover 4 that submerges the battery pack 102 does not participate in the circulation, and its specific heat capacity can also absorb the heat of the battery pack 102.

[0040] Refer to Figure 6 , when the ambient temperature T e > 15°C or the battery pack temperature T b > 30°C, and the battery pack temperature T b ≤ 35°C and the battery pack heat load 0 < a ≤ 0.05, the thermal management system of the present application is in the medium-load refrigeration mode of the battery pack. When the thermal management system is in the medium-load refrigeration mode of the battery pack 102, since the heat load of the battery pack 102 is medium and the temperature of the battery pack 102 has not reached a high temperature, the electronic expansion valve 16 and the stop valve 6 are closed; the output end of the first electronic water pump 14 is connected to the first end of the first three-way valve 15, the second end of the first three-way valve 15 is connected to the silicone oil channel of the dual-channel battery cold plate 5, the third end of the first three-way valve 15 is connected to the silicone oil inlet 110 of the protective cover 4, the silicone oil channel 107 of the dual-channel battery cold plate 5 and the silicone oil outlet 111 of the protective cover 4 are connected to the first end of the second three-way valve 7, the second end of the second three-way valve 7 is connected to the radiator 12, the radiator 12 is connected to the first compensation water tank 13, and the first compensation water tank 13 is connected to the input end of the first electronic water pump 14.

[0041] Silicone oil circuit: the first electronic water pump 14 drives the silicone oil 108 to flow through the E port, F port and G port of the first three-way valve 15 and then flow into the silicone oil channel 107 at the bottom of the dual-channel battery cold plate 5 and the silicone oil inlet 110 of the protective cover 4 respectively. After the silicone oil 108 in the dual-channel battery cold plate 5 absorbs the heat of the battery 102, it merges with the silicone oil 108 flowing out of the silicone oil outlet 111 of the protective cover 4, and flows into the radiator 12 after passing through the H port and I port of the second three-way valve 7. In the radiator 12, heat is exchanged with the external environment, and the absorbed heat of the battery pack 102 is dissipated into the environment. The silicone oil 108 immersed in the battery pack 102 in the protective cover 4 participates in the circulation, dissipates its own heat and then cools the battery pack 102.

[0042] See also Figure 7 , when the ambient temperature T e >15℃ or battery pack temperature T b >30℃, and the battery pack temperature T b >35℃, battery pack heat load a>0.05, the thermal management system of the present application is in the battery pack high load cooling mode. When the thermal management system is in the battery pack 102 high load cooling mode, the battery pack 102 has a large heat load and needs to be cooled as quickly as possible. At this time, the heat pump system is used to directly cool the battery pack 102, the electronic expansion valve 16 and the stop valve 6 are opened, the output end of the compressor 2 is connected to the first end of the four-way reversing valve 1, the third end of the four-way reversing valve 1 is connected to the input end of the compressor 2 through the gas-liquid separator 3, the second end of the four-way reversing valve 1 is connected to the external heat exchanger 18, and the external heat exchanger 18 is connected to the electronic expansion valve 16. 6 is connected to the refrigerant channel 105 of the dual-channel battery cold plate 5, the refrigerant channel 105 of the dual-channel battery cold plate 5 is connected to the stop valve 6, and the stop valve 6 is connected to the fourth end of the four-way reversing valve 1; the output end of the first electronic water pump 14 is connected to the first end of the first three-way valve 15, the third end of the first three-way valve 15 is connected to the silicone oil inlet 110 of the protective cover 4, the silicone oil outlet 111 of the protective cover 4 is connected to the first end of the second three-way valve 7, the third end of the second three-way valve 7 is connected to the silicone oil heat exchange channel of the plate heat exchanger 11, the silicone oil heat exchange channel of the plate heat exchanger 11 is connected to the first compensation water tank 13, and the first compensation water tank 13 is connected to the input end of the first electronic water pump 14. It should be noted that the parts not described in detail in this application are all prior art.

[0043] Refrigerant circuit: The high-temperature refrigerant at the outlet of the compressor 2 flows into the external heat exchanger 18 through the A port and the B port of the four-way reversing valve 1, exchanges heat with the ambient air blown in by the fan 17, and after being condensed, passes through the electronic expansion valve 16 to become a low-temperature refrigerant, and then flows into the refrigerant channel 105 of the dual-channel battery cold plate 5 to evaporate and absorb heat. After absorbing the heat of the battery pack 102, it flows into the gas-liquid separator 3 through the D port and the C port of the four-way reversing valve 1. The completely evaporated gaseous refrigerant flows into the inlet of the compressor 2.

[0044] Silicone oil circuit: the first electronic water pump 14 drives the silicone oil 108 to flow into the silicone oil inlet 110 of the protective cover 4 through the E port and the G port of the first three-way valve 15, so that the silicone oil 108 immersed in the battery pack participates in the circulation, and the temperature of the silicone oil 108 is reduced. At the same time, due to the low temperature of the refrigerant in the dual-channel battery cold plate 5, it is easy to cause the battery pack 102 in contact with the dual-channel battery cold plate 5. The bottom temperature of the battery pack 102 is low, while the surrounding or upper temperature is high. The silicone oil 108 can make the temperature of the battery pack 102 tend to be consistent. At this time, the silicone oil 108 no longer exchanges heat with the external environment, and returns to the input end of the first electronic water pump 14 through the plate heat exchanger 11 pipeline.

[0045] See also Figure 8 , when the ambient temperature T e ≤-5℃, the thermal management system of the present application is in the extremely low temperature heating mode of the battery pack. When the thermal management system is in the extremely low temperature heating mode of the battery pack 102, the heat pump system is used for low efficiency in winter when the temperature is low. At this time, the PTC electric heater 8 is used for heating, and the electronic expansion valve 16 and the stop valve 6 are closed; the output end of the first electronic water pump 14 is connected to the first end of the first three-way valve 15, the second end of the first three-way valve 15 is connected to the silicone oil channel 107 of the dual-channel battery cold plate 5, the third end of the first three-way valve 15 is connected to the silicone oil inlet 110 of the protective cover 4, the silicone oil channel 107 of the dual-channel battery cold plate 5 and the protective cover 4 are connected. The silicone oil outlet 111 of the protective cover 4 is connected to the first end of the second three-way valve 7, the second end of the second three-way valve 7 is connected to the silicone oil heat exchange channel of the plate heat exchanger 11, the silicone oil heat exchange channel of the plate heat exchanger 11 is connected to the first compensation water tank 13, the first compensation water tank 13 is connected to the input end of the first electronic water pump 14; the output end of the second electronic water pump 9 is connected to the PTC electric heater 8, the PTC electric heater 8 is connected to the coolant heat exchange channel of the plate heat exchanger 11, the coolant heat exchange channel of the plate heat exchanger 11 is connected to the second compensation water tank 10, and the second compensation water tank 10 is connected to the input end of the second electronic water pump 9.

[0046] Coolant circuit: The second electronic water pump 9 drives the coolant to flow through the PTC electric heater 8. The PTC electric heater 8 turns on the heating function to convert electrical energy into heat. After absorbing the heat of the PTC electric heater 8, the coolant flows into the coolant heat exchange channel of the plate heat exchanger 11 and transfers the heat to the silicone oil 108.

[0047] Silicone oil circuit: The first electronic water pump 14 drives the silicone oil 108 to absorb the heat generated by the PTC electric heater 8 in the coolant in the plate heat exchanger 11, and then flows into the silicone oil channel 107 of the dual-channel battery cold plate 5 and the protective cover 4 respectively, which can simultaneously transfer heat to the bottom, top and surrounding of the battery pack 102 to prevent uneven temperature.

[0048] See also Fig. 9 When the ambient temperature is -5℃ <T e≤15℃ or T e ≤-5℃ and battery pack temperature T b >15℃, the thermal management system of the present application is in the low-temperature heating mode of the battery pack 102. When the thermal management system is in the low-temperature heating mode of the battery pack 102, the heat pump system is more efficient in winter, or the temperature of the battery pack 102 is not low, and the use of the heat pump system for heating can save energy. The electronic expansion valve 16 and the stop valve 6 are opened, the output end of the compressor 2 is connected to the first end of the four-way reversing valve 1, the third end of the four-way reversing valve 1 is connected to the input end of the compressor 2 through the gas-liquid separator 3, the second end of the four-way reversing valve 1 is connected to the external heat exchanger 18, and the external heat exchanger 18 is connected to the refrigerant channel 105 of the dual-channel battery cold plate 5 through the electronic expansion valve 16. 05 is connected to the stop valve 6, and the stop valve 6 is connected to the fourth end of the four-way reversing valve 1; the output end of the first electronic water pump 14 is connected to the first end of the first three-way valve 15, the second end of the first three-way valve 15 is connected to the silicone oil channel 107 of the dual-channel battery cold plate 5, the third end of the first three-way valve 15 is connected to the silicone oil inlet 110 of the protective cover 4, the silicone oil channel 107 of the dual-channel battery cold plate 5 and the silicone oil outlet 111 of the protective cover 4 are connected to the first end of the second three-way valve 7, the second end of the second three-way valve 7 is connected to the silicone oil heat exchange channel of the plate heat exchanger 11, the silicone oil heat exchange channel of the plate heat exchanger 11 is connected to the first compensation water tank 13, and the first compensation water tank 13 is connected to the input end of the first electronic water pump 14.

[0049] Refrigerant circuit: The high-temperature refrigerant at the outlet of the compressor 2 flows into the refrigerant channel 105 of the dual-channel battery cold plate 5 through the A port and the D port of the four-way reversing valve 1 to condense and release heat, thereby heating the battery pack 102, and then exchanges heat with the ambient air blown in by the fan 17 in the external heat exchanger 18. After evaporation, it flows into the gas-liquid separator 3 through the B port and the C port of the four-way reversing valve 1. The completely evaporated gaseous refrigerant flows into the inlet of the compressor 2.

[0050] Silicone oil circuit: The first electronic water pump 14 drives the silicone oil 108 to flow into the silicone oil channel 107 of the dual-channel battery cold plate 5 and the protective cover 4 respectively. The silicone oil 108 absorbs the heat generated by the heat pump system in the silicone oil channel 107 of the dual-channel battery cold plate 5, and can transfer the heat to the upper part and surrounding of the battery pack 102 to prevent uneven temperature.

[0051] In addition, the battery pack 102 has a plurality of battery cells, the number of the battery cells is n, and the number of the tabs 101 on the battery pack 102 is two. The method for calculating the thermal load of the battery pack of the present application includes the following steps:

[0052] S1. Calculate the heat generation rate of a single battery cell. The heat generation rate of a single battery cell is calculated using the following formula: In the formula, q0 is the heat generation rate of a single battery cell, in W; I1 is the working current of the battery cell, in A; R is the sum of the ohmic internal resistance and polarization internal resistance of the battery cell, called the equivalent internal resistance, in Ω; T is the battery cell temperature, in K; It is the entropy thermal coefficient of the battery cell, which characterizes the reversible heat part of the heat generated by the battery cell, and its unit is V / K.

[0053] S2. Calculate the heat generation rate of the tabs. The heat generation rate of the tabs is calculated using the following formula: Where q1 is the heat generation rate of the tab, in W; I2 is the operating current of the battery pack, in A; r1 is the tab resistivity, in Ω·m; l1 is the tab length, in m; S1 is the tab cross-sectional area, in m 2 .

[0054] S3. Calculate the total heat generation rate of the battery pack. The total heat generation rate of the battery pack is calculated using the following formula: q=nq0+2q1 In the formula, q is the total heat generation rate of the battery pack, in W; q0 is the heat generation rate of a single battery cell, in W; q1 is the heat generation rate of the tab, in W;

[0055] S4. Calculate the heat exchange between the battery pack 102 and the dual-channel battery cold plate 5. The calculation formula is as follows: Q1=λ1S2(T b -T c ) Wherein, Q1 is the heat exchange between the battery pack 102 and the dual-channel battery cold plate 5, in W; λ1 is the heat exchange coefficient between the thermal pad 103 and the battery pack 102, in W / (m 2 ·K); S2 is the contact area between the battery pack 102 and the thermal pad 103, in m 2 ; T b is the temperature of the battery pack 102, in K; T c is the temperature of the thermal pad 103, in K.

[0056] S5. Calculate the heat exchange between the battery pack 102 and the silicone oil 108. The calculation formula is as follows: Q2=λ2S3(T b -T S ) Wherein, Q2 is the heat exchange between the battery pack 102 and the silicone oil 108, in W; λ2 is the heat exchange coefficient between the silicone oil 108 and the battery pack 102, in W / (m 2 ·K); S3 is the contact area between the battery pack 102 and the silicone oil 109, in m 2 ; T bis the temperature of the battery pack 102, in K; T S is the temperature of the silicone oil 108, in K.

[0057] S6. Calculate the total heat dissipation rate of the battery pack. The calculation formula is as follows: Q=Q1+Q2 Wherein, Q is the total heat dissipation rate of the battery pack, in W; Q1 is the heat exchange between the battery pack 102 and the dual-channel battery cold plate 5; Q2 is the heat exchange between the battery pack 102 and the silicone oil 108,

[0058] S7. Calculate the thermal load of the battery pack using the following formula: Wherein, a is the heat load of the battery pack, in units of °C / s, q is the total heat generation rate of the battery pack, in units of W; Q is the total heat dissipation rate of the battery pack 102, in units of W; c is the specific heat capacity of the battery pack 102, in units of J (kg·K), and m is the mass of the battery pack 102, in units of kg.

[0059] The battery pack heat load a is expressed as the temperature change of the battery pack per second.

[0060] It should be noted that the above embodiments are only used to illustrate the present invention, but the present invention is not limited to the above embodiments. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention fall within the protection scope of the present invention.

Claims

1. A large-capacity battery thermal load management system based on a composite cold plate, characterized in that: It comprises a refrigerant circuit, a silicone oil circuit, a cooling liquid circuit and a dual-channel battery cold plate (5), the refrigerant circuit is used to heat or cool the battery pack (102), and the battery silicone oil circuit is used to heat or cool the battery pack (102); the refrigerant circuit, the silicone oil circuit and the cooling liquid circuit cooperate to form a plurality of operation modes to achieve cooling or heating of the battery pack (102); The battery pack (102) is arranged at the upper end of the dual-channel battery cold plate (5); a protective cover (4) wrapping the battery pack (102) is provided at the upper end of the dual-channel battery cold plate (5); the protective cover (4) is filled with silicone oil (108); and the battery pack (102) is immersed in the silicone oil (108); The refrigerant circuit comprises a compressor (2), a four-way reversing valve (1), an external heat exchanger (18), an electronic expansion valve (16), a refrigerant channel (105) of a dual-channel battery cold plate (5), a stop valve (6) and a gas-liquid separator (3), and the components are connected by pipelines; The silicone oil circuit comprises a first electronic water pump (14), a first three-way valve (15), a protective cover (4), a silicone oil channel (107) of a dual-channel battery cold plate (5), a second three-way valve (7), a radiator (12), a silicone oil heat exchange channel of a plate heat exchanger (11) and a first compensation water tank (13), and the components are connected by pipelines; The coolant circuit comprises a second electronic water pump (9), a PTC electric heater (8), a coolant heat exchange channel of a plate heat exchanger (11), and a second compensation water tank (10); the components are connected via pipelines, and the battery pack (102) is cooled or heated by switching the valves.

2. The electric vehicle thermal management system based on battery cold plate enhanced heat transfer according to claim 1, characterized in that: The invention comprises a front cabin, wherein an external heat exchanger (18) and a radiator (12) are both arranged in the front cabin, and a fan (17) is installed at the front of the external heat exchanger (18).

3. The electric vehicle thermal management system based on battery cold plate enhanced heat transfer according to claim 1, characterized in that: The protective cover (4) has a silicone oil inlet (110) and a silicone oil outlet (111); the output end of the compressor (2) is connected to the first end of the four-way reversing valve (1); the third end of the four-way reversing valve (1) is connected to the input end of the compressor (2) via a gas-liquid separator (3); the second end of the four-way reversing valve (1) is connected to an external heat exchanger (18); the external heat exchanger (18) is connected to a refrigerant channel (105) of a dual-channel battery cold plate (5) via an electronic expansion valve (16); and the refrigerant channel (105) of the dual-channel battery cold plate (5) is connected to a fourth end of the four-way reversing valve (1) via a stop valve (6); The output end of the first electronic water pump (14) is connected to the first end of the first three-way valve (15); the second end of the first three-way valve (15) is connected to the first port of the second three-way valve (7) through the silicone oil channel (107) of the dual-channel battery cold plate (5); the third end of the first three-way valve (15) is connected to the silicone oil inlet (110) of the protective cover (4); the silicone oil outlet (111) of the protective cover (4) is connected to the first end of the second three-way valve (7); the second end of the second three-way valve (7) is connected to the radiator (12); the third end of the second three-way valve (7) is connected to the silicone oil heat exchange channel of the plate heat exchanger (11); and the silicone oil heat exchange channels of the radiator (12) and the plate heat exchanger (11) are connected to the input end of the first electronic water pump (14) through the first compensation water tank (13); The output end of the second electronic water pump (9) is connected to the coolant channel of the plate heat exchanger (11) via the PTC electric heater (8), and the coolant heat exchange channel of the plate heat exchanger (11) is connected to the input end of the second electronic water pump (9) via the second compensation water tank (10).

4. The electric vehicle thermal management system based on battery cold plate enhanced heat transfer according to claim 1, characterized in that: The operation modes of the thermal management system include the following five: Battery pack (102) low load cooling mode; Battery pack (102) medium load cooling mode; Battery pack (102) high load cooling mode; Battery pack (102) extremely low temperature heating mode; The battery pack (102) is in low temperature heating mode.

5. The electric vehicle thermal management system based on battery cold plate enhanced heat transfer according to claim 4, characterized in that: In a low-load cooling mode of the battery pack (102), the electronic expansion valve (16) and the stop valve (6) are closed; the output end of the first electronic water pump (14) is connected to the first end of the first three-way valve (15); the second end of the first three-way valve (15) is connected to the silicone oil channel (107) of the dual-channel battery cold plate (5); the silicone oil channel (107) of the dual-channel battery cold plate (5) is connected to the first end of the second three-way valve (7); the second end of the second three-way valve (7) is connected to the radiator (12); the radiator (12) is connected to the first compensation water tank (13); and the first compensation water tank (13) is connected to the input end of the first electronic water pump (14).

6. The electric vehicle thermal management system based on battery cold plate enhanced heat transfer according to claim 4, characterized in that: In the load cooling mode of the battery pack (102), the electronic expansion valve (16) and the stop valve (6) are closed; the output end of the first electronic water pump (14) is connected to the first end of the first three-way valve (15); the second end of the first three-way valve (15) is connected to the silicone oil channel (107) of the dual-channel battery cold plate (5); the third end of the first three-way valve (15) is connected to the silicone oil inlet (110) of the protective cover (4); the silicone oil channel (107) of the dual-channel battery cold plate (5) and the silicone oil outlet (111) of the protective cover (4) are both connected to the first end of the second three-way valve (7); the second end of the second three-way valve (7) is connected to the radiator (12); the radiator (12) is connected to the first compensation water tank (13); and the first compensation water tank (13) is connected to the input end of the first electronic water pump (14).

7. The electric vehicle thermal management system based on battery cold plate enhanced heat transfer according to claim 4, characterized in that: In the high-load cooling mode of the battery pack (102), the electronic expansion valve (16) and the stop valve (6) are opened, the output end of the compressor (2) is connected to the first end of the four-way reversing valve (1), the third end of the four-way reversing valve (1) is connected to the input end of the compressor (2) via the gas-liquid separator (3), the second end of the four-way reversing valve (1) is connected to the external heat exchanger (18), the external heat exchanger (18) is connected to the refrigerant channel (105) of the dual-channel battery cold plate (5) via the electronic expansion valve (16), the refrigerant channel (105) of the dual-channel battery cold plate (5) is connected to the stop valve (6), and the stop valve (6) is connected to the fourth end of the four-way reversing valve (1); The output end of the first electronic water pump (14) is connected to the first end of the first three-way valve (15), the third end of the first three-way valve (15) is connected to the protective cover (4), the protective cover (4) is connected to the first end of the second three-way valve (7), the third end of the second three-way valve (7) is connected to the silicone oil heat exchange channel of the plate heat exchanger (11), the silicone oil heat exchange channel of the plate heat exchanger (11) is connected to the first compensation water tank (13), and the first compensation water tank (13) is connected to the input end of the first electronic water pump (14).

8. The electric vehicle thermal management system based on battery cold plate enhanced heat transfer according to claim 4, characterized in that: In the extremely low temperature heating mode of the battery pack (102), the electronic expansion valve (16) and the stop valve (6) are closed; the output end of the first electronic water pump (14) is connected to the first end of the first three-way valve (15); the second end of the first three-way valve (15) is connected to the silicone oil channel (107) of the dual-channel battery cold plate (5); the third end of the first three-way valve (15) is connected to the silicone oil inlet (110) of the protective cover (4); the silicone oil channel (107) of the dual-channel battery cold plate (5) and the silicone oil outlet (111) of the protective cover (4) are both connected to the first end of the second three-way valve (7); the second end of the second three-way valve (7) is connected to the silicone oil heat exchange channel of the plate heat exchanger (11); the silicone oil heat exchange channel of the plate heat exchanger (11) is connected to the first compensation water tank (13); and the first compensation water tank (13) is connected to the input end of the first electronic water pump (14); The output end of the second electronic water pump (9) is connected to the PTC electric heater (8), the PTC electric heater (8) is connected to the coolant heat exchange channel of the plate heat exchanger (11), the coolant heat exchange channel of the plate heat exchanger (11) is connected to the second compensation water tank (10), and the second compensation water tank (10) is connected to the input end of the second electronic water pump (9).

9. The electric vehicle thermal management system based on battery cold plate enhanced heat transfer according to claim 4, characterized in that: In the low-temperature heating mode of the battery pack (102), the electronic expansion valve (16) and the stop valve (6) are opened, the output end of the compressor (2) is connected to the first end of the four-way reversing valve (1), the third end of the four-way reversing valve (1) is connected to the input end of the compressor (2) via the gas-liquid separator (3), the second end of the four-way reversing valve (1) is connected to the external heat exchanger (18), the external heat exchanger (18) is connected to the refrigerant channel (105) of the dual-channel battery cold plate (5) via the electronic expansion valve (16), the refrigerant channel (105) of the dual-channel battery cold plate (5) is connected to the stop valve (6), and the stop valve (6) is connected to the fourth end of the four-way reversing valve (1); The output end of the first electronic water pump (14) is connected to the first end of the first three-way valve (15); the second end of the first three-way valve (15) is connected to the silicone oil channel (107) of the dual-channel battery cold plate (5); the third end of the first three-way valve (15) is connected to the silicone oil inlet (110) of the protective cover (4); the silicone oil channel (107) of the dual-channel battery cold plate (5) and the silicone oil outlet (111) of the protective cover (4) are both connected to the first end of the second three-way valve (7); the second end of the second three-way valve (7) is connected to the silicone oil heat exchange channel of the plate heat exchanger (11); the silicone oil heat exchange channel of the plate heat exchanger (11) is connected to the first compensation water tank (13); and the first compensation water tank (13) is connected to the input end of the first electronic water pump (14).

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