Vehicle cabin and rechargeable energy storage system heating

Abstract

A heating, ventilation, and air conditioning (HVAC) system for a vehicle having a rechargeable energy storage system includes a refrigerant circuit in which a refrigerant flow circulates. The refrigerant circuit includes a compressor, an internal condenser, and a chiller heat exchanger. A coolant circuit is fluidly connected to the refrigerant circuit and has a coolant flow circulating therein. The coolant circuit includes the chiller heat exchanger, the internal condenser, a heater core, a rechargeable energy storage system (RESS), and a three-way coolant valve to selectively direct the coolant flow through the RESS and / or bypass the RESS along a bypass passage.

Description

TECHNICAL FIELD

[0001] The present invention relates to electric vehicles, and more particularly to heating of the passenger compartment and rechargeable energy storage system (RESS) of an electric vehicle. BACKGROUND

[0002] A typical RESS, also referred to by the term "battery pack" or other similar terms, has an optimum performance within a narrow temperature range. When operating conditions fall outside of this range at the upper end, the RESS is cooled by a coolant flow circulated therethrough. On the other hand, when operating temperatures are low, it is desirable to heat the RESS to maintain performance. Such heating is typically accomplished by a separate cooling heater connected to the system. SUMMARY

[0003] In an embodiment, a heating, ventilation, and air conditioning (HVAC) system for a vehicle having a rechargeable energy storage system includes a refrigerant circuit having a refrigerant flow circulated therethrough. The refrigerant circuit includes a compressor, an internal condenser, and a chiller heat exchanger. A coolant circuit is fluidly connected to the refrigerant circuit and has a coolant flow circulated therethrough. The coolant circuit includes the chiller heat exchanger, the internal condenser, a heater core, the rechargeable energy storage system (RESS), and a three-way coolant valve to selectively direct the coolant flow through the RESS and / or bypass the RESS along a bypass passage.

[0004] Additionally or alternatively, in this or other embodiments, the refrigerant circuit and the coolant circuit exchange thermal energy at the internal condenser.

[0005] Additionally or alternatively, in this or other embodiments, in a heat pump mode, the refrigerant flow is directed through an external heat exchanger of the refrigerant circuit, bypassing the chiller heat exchanger.

[0006] Additionally or alternatively, in this or other embodiments, the external heat exchanger expansion valve is operable to selectively direct the refrigerant flow through the external heat exchanger.

[0007] Additionally or alternatively, in this or other embodiments, the heat pump mode is utilized when the ambient temperature is greater than -10 degrees Celsius.

[0008] Additionally or alternatively, in this or other embodiments, the three-way coolant valve is located along the coolant circuit between the heater core and the chiller heat exchanger.

[0009] Additionally or alternatively, in this or other embodiments, the bypass passage extends from the three-way coolant valve to a location of the coolant circuit between the RESS and the internal condenser.

[0010] Additionally or alternatively, in this or other embodiments, in the RESS heating mode, refrigerant flow is directed through the chiller heat exchanger.

[0011] Additionally or alternatively, in this or other embodiments, the RESS heating mode is utilized when ambient air temperature is below -10 degrees Celsius.

[0012] Additionally or alternatively, in this or other embodiments, a pump circulates coolant flow through the coolant circuit.

[0013] Additionally or alternatively, in this or other embodiments, the pump is located in the coolant circuit upstream of the internal condenser and the heater core fluid, and downstream of the RESS fluid.

[0014] In another embodiment, a method of heating a rechargeable energy storage system of a vehicle includes circulating refrigerant flow through a refrigerant circuit. The refrigerant circuit includes a compressor, an internal condenser, and a chiller heat exchanger. Coolant flow is circulated through the coolant circuit. The coolant circuit includes the internal condenser, a heater core, and the rechargeable energy storage system (RESS). The refrigerant flow is heated by operation of the compressor. The coolant flow is selectively directed to one or more of the RESS and a bypass passage to bypass the RESS by a three-way coolant valve. One or more of the RESS and the heater core are heated by the coolant flow.

[0015] Additionally or alternatively, in this or other embodiments, the refrigerant circuit and the coolant circuit exchange thermal energy at the internal condenser.

[0016] Additionally or alternatively, in this or other embodiments, in the heat pump mode, refrigerant flow is directed through an external heat exchanger of the refrigerant circuit, bypassing the chiller heat exchanger.

[0017] Additionally or alternatively, in this or other embodiments, the heat pump mode is utilized when ambient temperature is greater than -10 degrees Celsius.

[0018] Additionally or alternatively, in this or other embodiments, the three-way coolant valve is located along the coolant circuit between the heater core and the chiller heat exchanger.

[0019] Additionally or alternatively, in this or other embodiments, the bypass passage extends from the three-way coolant valve to a location of the coolant circuit between the RESS and the internal condenser.

[0020] Additionally or alternatively, in this or other embodiments, in the RESS heating mode, refrigerant flow is directed through the chiller heat exchanger.

[0021] Additionally or alternatively, in this or other embodiments, the RESS heating mode is utilized when the ambient air temperature is below -10 degrees Celsius.

[0022] Additionally or alternatively, in this or other embodiments, the coolant flow is circulated through the coolant circuit via a pump located in the coolant circuit upstream of the fluid of the internal condenser and the heater core and downstream of the fluid of the RESS.

[0023] The above features and advantages of the present disclosure, and other features and advantages, will become apparent from the following detailed description, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0024] Other features, advantages, and details are described herein and become apparent to those skilled in the art, with the features and advantages being

[0025] Figure 1 is a schematic diagram of an embodiment of a heating, ventilation, and air conditioning (HVAC) system;

[0026] Figure 2 is a schematic diagram of a mode of operation of the HVAC system; and

[0027] Figure 3 is a schematic diagram of another mode of operation of the HVAC system. DETAILED DESCRIPTION

[0028] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0029] According to exemplary embodiments, Figure 1 A diagram of a heating, ventilation, and air conditioning (HVAC) system 10 for a vehicle is shown. The vehicle includes a rechargeable energy storage system (RESS) 12, such as a rechargeable traction battery, double layer capacitor, or flywheel energy storage, and a heater core 14 that is part of a coolant circuit 16 through which a coolant flow is circulated. The heater core 14 is used to heat a passenger compartment of the vehicle. The coolant flow is circulated through the coolant circuit 16 via a coolant pump 18, which in some embodiments is located between the RESS 12 and the heater core 14. An internal condenser 20 is positioned along the coolant circuit 16, in some embodiments between the coolant pump 18 and the heater core 14, and connects the coolant circuit 16 to a refrigerant circuit 22 that is arranged in parallel with the coolant circuit 16.

[0030] In the internal condenser 20, the coolant flow of the coolant circuit 16 exchanges thermal energy with the refrigerant flow from the refrigerant circuit 22. The refrigerant circuit 22 also includes a compressor 24 fluidly disposed upstream of the internal condenser 20, and three heat exchangers arranged in fluid parallel relationship downstream of the internal condenser 20. The three heat exchangers include an external heat exchanger 26, an evaporator 28, and a chiller heat exchanger 30. Each heat exchanger has an associated expansion device fluidly between the internal condenser 20 and the respective heat exchanger. The expansion devices are an external expansion valve 32, an evaporator expansion valve 34, and a chiller expansion valve 36, respectively. The chiller heat exchanger 30 is also connected to the coolant circuit 16 for exchange of thermal energy between the coolant flow and the refrigerant flow at the chiller heat exchanger 30.

[0031] The RESS valve 42 is used to connect the coolant circuit 16 and the power electronics coolant circuit 44, to exchange heat between the two coolant circuits as needed. In some embodiments, a coolant heater 46 can be placed between the RESS valve 42 and the pump 18 to provide additional heating to the RESS 12 and the vehicle cabin as needed. Alternatively, the coolant heater 46 can be placed between the chiller heat exchanger 30 and the RESS 12.

[0032] The HVAC system 10 is configured to operate in a variety of operating modes depending on the thermal demands of the RESS 12 and the heater core 14, as well as the environmental and operating conditions of the vehicle, which will be discussed in more detail below. To facilitate switching between operating modes, the HVAC system 10 includes a number of valves to selectively direct the coolant flow and the refrigerant flow along selected fluid paths in the coolant circuit 16 and the refrigerant circuit 22. The coolant circuit 16 includes a three-way coolant valve 38 to selectively direct the coolant flow through the chiller heat exchanger 30 and / or through a bypass passage 40 to a location between the pump 18 and the RESS 12, to bypass the RESS 12 and the chiller heat exchanger 30. In addition to the expansion valves described above, the refrigerant circuit 22 includes an external heat exchanger valve 52 and an internal condenser refrigerant valve 54 to selectively direct the refrigerant flow from the compressor 24 through the external heat exchanger 26 or the internal condenser 20.

[0033] A first operating mode or heat pump mode of the HVAC system 10 is to provide heating to the vehicle cabin and the RESS 12. In the heat pump mode, the coolant flow is directed through the chiller heat exchanger 30 and the bypass passage 40 to bypass the RESS 12. The refrigerant flow is directed through the external heat exchanger 26 and the evaporator 28. The coolant flow is heated in the chiller heat exchanger 30 and the bypass passage 40, and the refrigerant flow is cooled in the external heat exchanger 26 and the evaporator 28. The heated coolant flow is used to heat the vehicle cabin and the RESS 12. Figure 2The first mode is shown in FIG. 2. For example, when the ambient temperature is not below -10 degrees Celsius and one or more of the RESS 12 or the cabin requests heating, the cabin is heated with the first mode by the heater core 14. In the heat pump mode, the outside expansion valve 32 is open, the evaporator expansion valve 34, the chiller expansion valve 36, and the outside heat exchanger valve 52 are all closed. Thus, in the refrigerant circuit 22, the refrigerant flow exits the compressor 24 and is directed through the inside condenser 20, then through the outside expansion valve 32 and the outside heat exchanger 26, which absorbs heat from the ambient air. The refrigerant flow bypasses the evaporator 34 and the chiller heat exchanger 30 and returns to the compressor 24. In the coolant circuit 16, heat energy is exchanged between the coolant flow at the inside condenser 20 and the refrigerant flow. The heated coolant flow then flows through the heater core 14 and is selectively directed through the three-way coolant valve 38 to the RESS 12 and / or through the bypass passage 40 depending on the heating requirements of the RESS 12. When both the cabin and the RESS 12 require heating, the heating of the RESS 12 will be limited, otherwise the RESS 12 will act as a radiator and direct all of the coolant flow to the RESS 12.

[0034] Referring now to Figure 3 , a second mode of operation of the HVAC system 10 is shown, the RESS heating mode. This second mode is used in cold conditions, for example, when the ambient temperature is below -10 degrees Celsius and one or more of the RESS 12 or the cabin requests heating, the cabin is heated with the heater core 14. In the RESS heating mode, the outside expansion valve 32 and the evaporator expansion valve 34 are closed, and the outside heat exchanger valve 52 is also closed. The chiller expansion valve 36 is open so that in the refrigerant circuit 22, the refrigerant flow exits the compressor 24 and is directed through the inside condenser 20, then through the chiller expansion valve 36 and the chiller heat exchanger 30 before flowing back to the compressor 24.

[0035] In the coolant circuit 16, heat energy is exchanged between the coolant flow at the inside condenser 20 and the refrigerant flow. The heated coolant flow then flows through the heater core 14 and is selectively directed through the three-way coolant valve 38 to the RESS 12 and / or through the bypass passage 40 depending on the heating requirements of the RESS 12. When both the cabin and the RESS 12 require heating, the heating of the RESS 12 will be limited, otherwise the RESS 12 will act as a radiator and direct all of the coolant flow to the RESS 12.

[0036] The use of the three-way coolant valve 38 allows for the regulation of the coolant flow through the chiller heat exchanger 30 and the RESS 12 so that the RESS 12 can be heated by the coolant flow that is waste heat that is not used by the heater core 14 for cabin heating.

[0037] While the foregoing disclosure has been described in reference to exemplary embodiments, it will be understood by those skilled in the art that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope thereof. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the disclosure without departing from the central scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiment disclosed, but will include all embodiments falling within the scope of the disclosure.

Claims

1. A heating, ventilation, and air conditioning (HVAC) system for a vehicle having a rechargeable energy storage system (RESS), comprising: a refrigerant circuit through which a refrigerant flow circulates, the refrigerant circuit comprising: a compressor; an internal condenser; an evaporator; and a chiller heat exchanger arranged in fluid parallel relationship with the evaporator; and a coolant circuit fluidly connected to the refrigerant circuit and having a coolant flow circulating therethrough, the coolant circuit comprising: the chiller heat exchanger; the internal condenser; a heater core; the rechargeable energy storage system (RESS); a coolant heater; and a three-way coolant valve selectively directing the coolant flow through both the rechargeable energy storage system (RESS) and the chiller heat exchanger and along a bypass passage around all of the rechargeable energy storage system (RESS), the chiller heat exchanger, and the coolant heater; wherein the three-way coolant valve is located along the coolant circuit between the heater core and the chiller heat exchanger; and further comprising a power electronics coolant circuit fluidly connected to the coolant circuit; wherein the coolant flow is selectively directed through the power electronics coolant circuit via a rechargeable energy storage system (RESS) valve located fluidly downstream of the rechargeable energy storage system (RESS).

2. The heating, ventilation, and air conditioning (HVAC) system of claim 1, wherein, the refrigerant circuit and the coolant circuit exchange thermal energy at the internal condenser.

3. The heating, ventilation, and air conditioning (HVAC) system of claim 1, wherein, in a heat pump mode, the refrigerant flow is directed through the external heat exchanger of the refrigerant circuit, bypassing the chiller heat exchanger.

4. The heating, ventilation, and air conditioning (HVAC) system of claim 1, wherein, the bypass passage extends from the three-way coolant valve to a location of the coolant circuit between the rechargeable energy storage system (RESS) and the internal condenser.

5. The heating, ventilation, and air conditioning (HVAC) system of claim 1, wherein, in a rechargeable energy storage system (RESS) heating mode, the refrigerant flow is directed through the chiller heat exchanger.

6. A method of heating a rechargeable energy storage system (RESS) of a vehicle having a heating, ventilation, and air conditioning (HVAC) system in accordance with any one of claims 1-5, comprising: circulating a refrigerant flow through the refrigerant circuit; circulating a coolant flow through the coolant circuit; heating the refrigerant flow by operation of the compressor; selectively directing the coolant flow to both the rechargeable energy storage system (RESS) and the chiller heat exchanger and along a bypass passage around all of the rechargeable energy storage system (RESS), the chiller heat exchanger, and the coolant heater via the three-way coolant valve; and heating one or more of the rechargeable energy storage system (RESS) and the heater core via the coolant flow. ​

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