Thermal control system for the passenger compartment and battery of an electric vehicle, including a gas-injection heat pump circuit

Abstract

This thermal control system includes a gas-injected heat pump circuit (1) configured to thermally regulate the passenger compartment of an electric or hybrid vehicle. The system further includes a battery heating circuit (60) with a heat exchanger (61) configured to supply heat to a heat exchange fluid in a thermal management circuit (BC) of a battery (B) of the vehicle. The gas-injected heat pump circuit includes a separation valve assembly (55) located downstream of the battery heating circuit (60). This separation valve assembly (55) is capable of separating the refrigerant into gaseous and liquid phases and is configured to selectively inject the gaseous phase into a compressor (10) of the heat pump circuit (1) and inject the liquid phase into an external heat exchanger (3). Figure for the abstract: [Fig 1]

Description

Title of the invention: Thermal regulation system for the passenger compartment and battery of an electric vehicle comprising a gas injection heat pump circuit technical field

[0001] The present invention relates to a thermal regulation system for the passenger compartment and battery of an electric or hybrid vehicle. More specifically, the present invention relates to a thermal regulation system comprising a heat pump circuit. Previous techniques

[0002] Electric or hybrid electric vehicles waste little heat and therefore generally rely on electric heaters to heat the passenger compartment, and / or the battery, and / or the components of the electric drive system.

[0003] Electric heaters use high-voltage battery power to generate heat, which is then distributed to the desired parts of the vehicle.

[0004] Electric heaters are costly components of electric vehicle thermal systems with high electrical energy consumption, to such an extent that reducing or eliminating their presence would prove beneficial both economically and in terms of energy savings.

[0005] Thermodynamic heating systems, such as heat pump circuits, are used to reduce the need for electric heating.

[0006] However, the efficiency of thermodynamic heating systems is thermally limited at low temperatures, in particular because the mass flow rate of refrigerant decreases with ambient temperature.

[0007] A gas injection technology, which separates the gaseous and liquid phases of a refrigerant before entering an external heat exchanger and injects the gaseous part into the compressor, can improve the heating performance of thermodynamic heating systems by making the refrigerant mass flow less sensitive to external temperature conditions.

[0008] However, when the outside temperature falls below a certain threshold (for example -10 °C), the gas injection system cannot sufficiently heat the passenger compartment to meet passenger comfort requirements. In this case, a high-voltage heater must compensate for the difference. Description of the invention

[0009] An objective of the present invention is to increase heating performance at very negative ambient temperatures, thereby at least partially avoiding the use of high-voltage heaters.

[0010] According to one embodiment, a thermal control system includes a gas-injection heat pump circuit configured to thermally regulate the passenger compartment of an electric vehicle or a hybrid electric vehicle. The system further includes a battery heating circuit equipped with a battery heating heat exchanger configured to supply heat to a heat exchange fluid in a thermal management circuit for a vehicle battery. In addition to regulating the temperature in the passenger compartment, such a system can also supply heat to the vehicle battery.By utilizing the thermal management fluid, at least partially, as a heat sink, the coefficient of performance (COP) of the heat pump system increases due to the smaller temperature difference between the cold source (external temperature) and the heat sink (temperature of the thermal management fluid relative to the cabin temperature). Furthermore, the gas-injection heat pump maximizes efficiency by selectively increasing the refrigerant flow rate, thereby improving electrical consumption. In addition, such a system reduces or even eliminates the need for electric heaters for battery heating, further improving electrical efficiency.

[0011] In such a thermal regulation system, when battery heating is no longer required, the heat supplied by the heat pump circuit can advantageously be stored in the battery thermal management fluid. For example, when passenger compartment heating is required, the stored heat can be recovered from the battery thermal management fluid via a heat recovery method. Such a heat recovery method does not negatively impact the vehicle's aerodynamic coefficient, unlike the use of an external heat exchanger to heat an incoming airflow.

[0012] Similarly, when an electric route planner (ERP) detects a short vehicle journey with cabin dehumidification / cooling requirements (e.g., from home to the office or similar), thermal energy can be transferred to the battery instead of being released to the environment, thus saving energy by keeping the grille shutter closed and the front cooling fan inactive. The battery can slowly dissipate the heat received during the parking period (e.g., overnight or while parked during office hours).

[0013] More generally, such a system allows an energy optimization strategy to store and release heat according to the heating requirements of the battery and the passenger compartment.

[0014] In one embodiment, the battery heating circuit is placed downstream of a compressor of the heat pump circuit and is mounted in parallel with a cabin heating condenser of the heat pump circuit.

[0015] During cabin cooling conditioning, such a condenser can be used to recover heat from the cabin and transfer it to the battery via the battery heating circuit and achieve a battery temperature compatible with fast charging.

[0016] Advantageously, the battery heating circuit is equipped with a first valve mounted upstream of the battery heating heat exchanger, the heat pump circuit being equipped with a second valve mounted downstream of the compressor and upstream of the cabin heating condenser.

[0017] For example, the first and second valves are expansion valves or shut-off valves.

[0018] Preferably, the battery heating circuit is equipped with a first non-return valve mounted upstream of the battery heating heat exchanger, the heat pump circuit being equipped with a second non-return valve mounted downstream of the cabin heating condenser.

[0019] Advantageously, the system further comprises a battery cooling circuit with a battery cooling heat exchanger configured to extract heat from the heat exchange fluid of the battery thermal management circuit. Such a system improves efficiency by recovering residual heat generated by the battery and using it for passenger compartment heating. In addition, efficient battery temperature control allows the battery to operate at optimal performance, and the total vehicle mileage can be increased through efficient battery management.

[0020] In one embodiment, the battery cooling circuit is provided upstream of a compressor of the heat pump circuit and is mounted in parallel with a cabin cooling evaporator of the heat pump circuit.

[0021] For example, the fluid used by the battery thermal management circuit is water.

[0022] Preferably, the system is equipped with an electric air heater for heating the passenger compartment.

[0023] According to another aspect, the invention relates to an electric vehicle or a hybrid electric vehicle comprising a thermal regulation system as described above. Brief description of the drawings

[0024] The present invention and its advantages will be better understood upon study of the detailed description of a specific embodiment presented by way of non-limiting example and illustrated by the accompanying drawings in which:

[0025] [Fig. 1] illustrates a schematic diagram of a thermal regulation system for a vehicle according to one embodiment of the invention;

[0026] [Fig.2] is a cross-sectional view of a gas and liquid separation valve of the thermal control system of [Fig.1] during an active gas injection cycle; and

[0027] [Fig.3] is a view of the separation valve of [Fig.2] during an idle gas injection cycle. Detailed description of at least one embodiment

[0028] The thermal regulation system shown in [Fig.1] includes a gas injection heat pump circuit 1 configured to circulate a refrigerant to thermally regulate the passenger compartment of an electric vehicle or a hybrid electric vehicle.

[0029] The heat pump circuit 1 includes a cabin heating condenser 2 and an external heat exchanger 3.

[0030] The passenger compartment heater condenser 2 is configured to be installed inside an air conditioning control unit H intended to provide air conditioning inside the vehicle's passenger compartment. The external heat exchanger 3 is configured to be installed on the front side of the vehicle and has a surface for heat exchange between the refrigerant and an airflow F intended to pass through the heat exchanger 3.

[0031] The heat pump circuit 1 includes a compressor 10 and, downstream of the compressor 10 in the refrigerant flow direction, the cabin heating condenser 2 and the external heat exchanger 3. An inlet 2a of the cabin heating condenser 2 is connected to a discharge side 10a of the compressor 10.

[0032] The thermal regulation system further includes a battery cooling circuit 29 equipped with a battery cooling heat exchanger 30. The battery cooling circuit 29 is provided upstream of a compressor 10 of the heat pump circuit 1 and is mounted in parallel with the passenger compartment cooling evaporator 20 of the heat pump circuit 1.

[0033] As illustrated in [Fig. 1], further downstream of the heat exchanger 3, the thermal regulation system comprises a first branch 12 provided for the heat pump circuit and a second branch 14 provided for the cooling circuit of battery 29. The first and second branches 12, 14 are arranged in parallel between the external heat exchanger 3 and the compressor 10.

[0034] The first branch 12 is provided with a first expansion valve 18 and a passenger compartment cooling evaporator 20. The passenger compartment cooling evaporator 20 is part of the air conditioning unit H and is configured to allow heat exchange between the refrigerant of the heat pump circuit 1 and an airflow intended to cool the vehicle passenger compartment. The air conditioning unit H may further include a fan 21 or a blower configured to generate said airflow, a door assembly 22 configured to direct / divert said airflow along predetermined paths, and an electric heater 23, for example a PTC heater or a self-regulating heater, configured to heat said airflow. The first branch 12 further includes a check valve 20a.

[0035] The second branch 14 is equipped with a second expansion valve 24 and the battery cooling heat exchanger 30.

[0036] The battery cooling heat exchanger 30, commonly called a cooler, is configured to extract heat from a heat exchange fluid of a thermal management system BC of a battery B of the vehicle.

[0037] As shown in a simplified way in [Fig. 1], the fluid for the thermal management of battery B circulates in a separate circuit BC dedicated to the thermal management of battery B.

[0038] If cooling of battery B is required, the heat exchange between the circuit refrigerant 1 and the thermal management fluid of battery B inside the cooler 30 causes evaporation of the refrigerant and, consequently, cooling of the thermal management fluid of the battery.

[0039] The circuit 1 may further include an accumulator 31, arranged downstream of a point of confluence between the first branch 12 and the second branch 14 and upstream of the compressor 10. An output of the accumulator 31 is connected to a first suction inlet 10b of the compressor 10.

[0040] The heat pump circuit 1 may further include a first bypass branch 41, having an upstream end connected to a return pipe 43 of circuit 1 linking an inlet 3a of the external heat exchanger 3 and the third expansion valve 4 to an outlet 2b of the cabin heater condenser 2, and a downstream end connected to a pipe 44 linking a branch point of the first branch 12 and the second branch 14 to an outlet 3b of the external heat exchanger 3. The first bypass branch 41 includes a two-way valve 42, which can be controlled to selectively assume a first position in which the first bypass branch 41 is closed and circuit 1 is configured to operate in a passenger compartment cooling, heating, or dehumidification configuration, and a second position in which the first branch 41 is open and circuit 1 is configured to operate in a heating configuration with residual heat recovery. In the cooling configuration, the heat exchanger 3 ensures that the heat generated by the cooling of battery B, via cooler 30, and / or the air conditioning unit H, after passing through the passenger compartment heating condenser 2, is dissipated into the air.

[0041] A non-return valve 45 can also be arranged on the pipe 44, upstream of the downstream end of the first branch 41.

[0042] The heat pump circuit 1 may further include a second branch 51, having an upstream end connected to the pipe 44 upstream of the associated check valve 45, and a downstream end connected to an inlet of the accumulator 31. The second branch 51 includes a two-way valve 52, which can be controlled to selectively assume a first position in which the second branch 51 is closed and the refrigerant from the external heat exchanger 3 is routed to the first branch 12 and the second branch 14, and a second position in which the second branch 51 is open and the refrigerant from the external heat exchanger 3 is routed to the accumulator 31. The second branch 51 further includes a check valve 53.

[0043] The heat pump circuit 1 further includes a separation valve assembly 55 positioned downstream of a third expansion valve 4 and upstream of the external heat exchanger 3. The separation valve assembly 55 includes an inlet 55a connected to the outlet 2b of the cabin heating condenser 2 via a non-return valve 65 and the third expansion valve 4. The separation valve assembly 55 further includes a first outlet 55b connected to the inlet 3a of the external heat exchanger 3, and a second outlet 55c connected to a second suction inlet 10c of the compressor 10.

[0044] An example of a separation valve assembly is illustrated in Figures 2 and 3, in which the separation valve assembly 55 is shown respectively in an active gas injection cycle position and in an inactive gas injection cycle position. In the illustrated example, the separation valve assembly 55 includes a gas and liquid separator 55d arranged downstream of the inlet 55a of the separation valve assembly 55. A liquid outlet of the gas and liquid separator is connected to the first outlet 55b of the separation valve assembly 55 via a first conduit 55e and a second conduit 55f arranged in parallel with the first conduit 55e. The first conduit 55e is fitted with a butterfly valve 55g, and the second Conduit 55f is equipped with a bidirectional valve 55h, functional for selectively closing ([Fig. 2]) or opening ([Fig. 3]) the second conduit 55f. A gas outlet from the gas and liquid separator 55d is connected to the second outlet 55c of the separation valve assembly 55 via a valve 55i which selectively allows ([Fig. 2]) or prevents ([Fig. 3]) fluid communication between the gas outlet and the second outlet 55c of the separation valve assembly 55, depending on the pressure difference between the gas outlet of the gas and liquid separator 55d and the first outlet 55b of the separation valve assembly 55. The construction shown in Figures 2 and 3 is only one possible embodiment of the separation valve assembly 55; those skilled in the art know that other known features can be used to carry out the gas injection cycle.

[0045] The gas injection cycle ([Fig. 2]) expands the refrigerant from a high-pressure level to an intermediate-pressure level. This generates a two-phase refrigerant at intermediate pressure, which is separated into gas and liquid. The gas is reinjected into the compressor 10, and the liquid is further expanded and supplied to the external heat exchanger 3 for evaporation. The enthalpy increases as the gaseous refrigerant returns to the compressor at intermediate pressure, while the fraction of liquid refrigerant available for evaporation increases, thus improving heat absorption from the external environment. Due to the injection of a high-density gaseous refrigerant at the second suction inlet 10c of the compressor, the refrigerant mass flow rate and heating performance also increase.

[0046] The thermal regulation system further includes a battery heating circuit 60 equipped with a battery heating heat exchanger 61.

[0047] The battery heating circuit 60 connects the discharge side 10a of the compressor to the return line 43 of the heat pump circuit 1. The battery heating circuit 60 is mounted in parallel with the cabin heating condenser 2 of the heat pump circuit 1.

[0048] The heating heat exchanger 61, preferably a condenser, is configured to supply heat to a heat exchange fluid of the thermal management circuit BC of the vehicle's battery B.

[0049] Preferably, the heat exchange fluid of the thermal management circuit BC of battery B is water.

[0050] In [Fig. 1], for the sake of simplicity, the thermal management circuit BC dedicated to the thermal management of battery B is represented as two separate circuits, one coupled to the cooling heat exchanger 30 and the other coupled to the heating heat exchanger 61. It should be understood, however, that it is the same circuit, equipped with valves and other devices dedicated to sorting the thermal management fluid according to the objectives to be achieved (i.e., cooling). or battery heating). The configuration of such a thermal management circuit is known and is therefore not detailed here.

[0051] The battery heating circuit 60 is provided upstream of the battery heating heat exchanger 61 with a fourth expansion valve 62. Correspondingly, a fifth expansion valve 63 is arranged upstream of the passenger compartment condenser 2.

[0052] According to an alternative embodiment, the two valves 62, 63 are stop valves.

[0053] The battery heating branch 60 is provided downstream of the battery heating heat exchanger 61 with a first non-return valve 64.

[0054] Correspondingly, a second non-return valve 65 is provided downstream of the passenger compartment heater condenser 2.

[0055] If heating of battery B is required, the heat exchange between the refrigerant of circuit 1 and the thermal management fluid of battery B inside the heating heat exchanger 61 causes condensation of the refrigerant and, consequently, heating of the thermal management fluid of battery B.

[0056] Although the disclosure has been described in relation to what are currently considered to be practical embodiments, it should be understood that the disclosure is not limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and various equivalent arrangements included in the spirit and scope of the annexed claims.

Claims

Demands

1. A thermal control system comprising a gas-injected heat pump circuit (1) configured to circulate a refrigerant for thermally regulating the passenger compartment of an electric vehicle or a hybrid electric vehicle, characterized in that said system further comprises a battery heating circuit (60) having a battery heating heat exchanger (61) configured to supply heat to a heat exchange fluid of a thermal management circuit (BC) of a battery (B) of the vehicle, said gas-injected heat pump circuit comprising a separation valve assembly (55) located downstream of the battery heating circuit (60), said separation valve assembly (55) being able to operate to separate the refrigerant into gaseous and liquid phases,and being configured to selectively inject the gaseous phase into a compressor (10) of the heat pump circuit (1) and inject the liquid phase into an external heat exchanger (3).

2. System according to claim 1, wherein the battery heating circuit (60) is placed downstream of the compressor (10) of the heat pump circuit (1) and is mounted in parallel with a cabin heating condenser (2) of the heat pump circuit (1).

3. System according to claim 2, wherein the battery heating circuit (60) is provided with a valve (62) mounted upstream of the battery heating heat exchanger (61), the heat pump circuit (1) being provided with another valve (63) mounted downstream of the compressor (10) and upstream of the cabin heating condenser (2).

4. System according to claim 3, wherein the valves (62, 63) are both expansion valves or shut-off valves.

5. System according to any one of claims 1 to 4, wherein the battery heating circuit (60) is provided with a first check valve (64) mounted upstream of the battery heating heat exchanger (61), the heat pump circuit (1) being provided with a second check valve (65) mounted downstream of the cabin heating condenser (2).

6. A system according to any one of claims 1 to 5, wherein the system further comprises a cooling circuit battery (29) equipped with a battery cooling heat exchanger (30) configured to extract heat from the heat exchange fluid of the thermal management circuit (BC) of the battery (B).

7. System according to claim 6, wherein the battery cooling circuit (29) is provided upstream of a compressor (10) of the heat pump circuit (1) and is mounted in parallel with a cabin cooling evaporator (20) of the heat pump circuit (1).

8. System according to any one of claims 1 to 7, wherein the fluid used by the thermal management circuit of the battery (B) is water.

9. System according to any one of claims 1 to 8, wherein said system is equipped with an electric air heater (23) for heating the passenger compartment.

10. Electric or hybrid electric vehicle comprising a thermal regulation system according to any one of claims 1 to 9.

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