Patent Publication Number: US-2023147794-A1

Title: Vehicle cabin and rechargeable energy storage system heating

Description:
INTRODUCTION 
     The subject disclosure relates to electric vehicles, and more precisely to heating of a cabin and a rechargeable energy storage system (RESS) of an electric vehicle. 
     A typical RESS, also known by the term a “battery pack” or other similar nomenclature has an optimal performance within a narrow temperature range. When operating conditions fall outside of this range at an upper end, the RESS is cooled by circulating a flow of coolant therethrough. When, on the other hand, the operating temperature is low, it is desired to heat RESS to maintain performance. This heating is typically achieved via a separate cooling heater connected to the system. 
     SUMMARY 
     In one embodiment, a heating, ventilation and air conditioning (HVAC) system for a vehicle having a rechargeable energy storage system includes a refrigerant circuit having a flow of refrigerant 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 flow of coolant circulated therethrough. 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 selectably direct the flow of coolant through the RESS and/or along a bypass passage to bypass the RESS. 
     Additionally or alternatively, in this or other embodiments the refrigerant circuit and the coolant circuit exchange thermal energy at the internal condenser. 
     Additionally or alternatively, in this or other embodiments in a heat pump mode, the flow of refrigerant is directed through an outside heat exchanger of the refrigerant circuit, bypassing the chiller heat exchanger. 
     Additionally or alternatively, in this or other embodiments an outside heat exchanger expansion valve is operable to selectably direct the flow of refrigerant through the outside heat exchanger. 
     Additionally or alternatively, in this or other embodiments the heat pump mode is utilized when an ambient temperature is greater than −10 degrees Celsius. 
     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. 
     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. 
     Additionally or alternatively, in this or other embodiments in a RESS heating mode, the flow of refrigerant is directed through the chiller heat exchanger. 
     Additionally or alternatively, in this or other embodiments the RESS heating mode is utilized when an ambient air temperature is less than −10 degrees Celsius. 
     Additionally or alternatively, in this or other embodiments a pump circulates the flow of coolant through the coolant circuit. 
     Additionally or alternatively, in this or other embodiments the pump is located in the coolant circuit fluidly upstream of the internal condenser and the heater core, and fluidly downstream of the RESS. 
     In another embodiment, a method of heating a rechargeable energy storage system of a vehicle includes circulating a flow of refrigerant through a refrigerant circuit. The refrigerant circuit includes a compressor, an internal condenser, and a chiller heat exchanger. A flow of coolant is circulated through a coolant circuit. The coolant circuit includes the internal condenser, a heater core, and a rechargeable energy storage system (RESS). The flow of refrigerant is heated via operation of the compressor. The flow of coolant is selectably directed to one or more of the RESS and a bypass passage to bypass the RESS via a three-way coolant valve. One or more of the RESS and the heater core are heated via the flow of coolant. 
     Additionally or alternatively, in this or other embodiments the refrigerant circuit and the coolant circuit exchange thermal energy at the internal condenser. 
     Additionally or alternatively, in this or other embodiments in a heat pump mode, the flow of refrigerant is directed through an outside heat exchanger of the refrigerant circuit, bypassing the chiller heat exchanger. 
     Additionally or alternatively, in this or other embodiments the heat pump mode is utilized when an ambient temperature is greater than −10 degrees Celsius. 
     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. 
     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. 
     Additionally or alternatively, in this or other embodiments in a RESS heating mode, the flow of refrigerant is directed through the chiller heat exchanger. 
     Additionally or alternatively, in this or other embodiments the RESS heating mode is utilized when an ambient air temperature is less than −10 degrees Celsius. 
     Additionally or alternatively, in this or other embodiments the flow of coolant is circulated through the coolant circuit via a pump, the pump located in the coolant circuit fluidly upstream of the internal condenser and the heater core, and fluidly downstream of the RESS. 
     The above features and advantages, and other features and advantages of the disclosure are readily apparent from the following detailed description when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features, advantages and details appear, by way of example only, in the following detailed description, the detailed description referring to the drawings in which: 
         FIG.  1    is a schematic illustration of an embodiment of a heating, ventilation, and air conditioning (HVAC) system; 
         FIG.  2    is a schematic illustration of an operating mode of an HVAC system; and 
         FIG.  3    is a schematic illustration of another operating mode of an HVAC system. 
     
    
    
     DETAILED DESCRIPTION 
     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. 
     In accordance with an exemplary embodiment, an illustration of a heating, ventilation, and air conditioning (HVAC) system  10  for a vehicle is shown in  FIG.  1   . The vehicle includes a rechargeable energy storage system (RESS)  12 , such as electric rechargeable traction batteries, electric double-layer capacitors or flywheel energy storage, and a heater core  14  as part of a coolant circuit  16 , through which a flow of coolant is circulated. The heater core  14  is utilized for heating of a cabin of the vehicle. The flow of coolant 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 located 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  arranged in parallel with the coolant circuit  16 . 
     In the internal condenser  20 , the flow of coolant of the coolant circuit  16  exchanges thermal energy with a flow of refrigerant from the refrigerant circuit  22 . The refrigerant circuit  22  further includes a compressor  24  disposed fluidly upstream of the internal condenser  20 , and three heat exchangers arranged in a fluidly parallel relationship downstream of the internal condenser  20 . The three heat exchangers include an outside heat exchanger  26 , an evaporator  28  and a chiller heat exchanger  30 . Each heat exchanger has an associated expansion device located fluidly between the internal condenser  20  and the respective heat exchanger. The expansion devices are, respectively, an outside expansion valve  32 , an evaporator expansion valve  34  and a chiller expansion valve  36 . The chiller heat exchanger  30  is further connected to the coolant circuit  16  for thermal energy exchange between the flow of coolant and the flow of refrigerant at the chiller heat exchanger  30 . 
     A RESS valve  42  is used to connect the coolant circuit  16  and a power electronics coolant loop  44 , thereby exchanging heat between the two coolant loops on an as needed basis. 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 cabin on an as needed basis. Alternatively, the coolant heater  46  can be placed between chiller heat exchanger  30  and the RESS  12 . 
     The HVAC system  10  is configured to operate in several operating modes, depending on the thermal demands of the RESS  12  and the heater core  14 , and on ambient conditions and operating conditions of the vehicle, as will be discussed in greater detail below. To facilitate switching of operating modes, the HVAC system  10  includes a plurality of valves to selectably direct the flow of coolant and the flow of refrigerant along selected fluid pathways in the coolant circuit  16  and the refrigerant circuit  22 . The coolant circuit  16  includes a three-way coolant valve  38  to selectably direct the flow of coolant through the chiller heat exchanger  30  and/or through a bypass passage  40  to a location between the pump  18  and the RESS  12 , thus bypassing the RESS  12  and the chiller heat exchanger  30 . In addition to the aforementioned expansion valves, the refrigerant circuit  22  includes an outside heat exchanger valve  52  and an internal condenser refrigerant valve  54  to selectably direct the flow of refrigerant from the compressor  24  through the outside heat exchanger  26  or through the internal condenser  20 . 
     A first operating mode, or heat pump mode, of the HVAC system  10  is illustrated in  FIG.  2   . This first mode is utilized, for example, when the ambient temperature is not less than −10 degrees Celsius, and one or more of the RESS  12  or the cabin is requesting heating, with the cabin being heated via the heater core  14 . In heat pump mode, the outside expansion valve  32  is opened, and 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 flow of refrigerant leaves the compressor  24  and is directed through the internal condenser  20 , and then through the outside expansion valve  32  and the outside heat exchanger  26 , which draws in heat from the ambient air. The flow of refrigerant bypasses the evaporator  34  and the chiller heat exchanger  30  and is returned to the compressor  24 . In the coolant loop  16 , thermal energy is exchanged between the flow of coolant and the flow of refrigerant at the internal condenser  20 . The heated flow of coolant then flows through the heater core  14  and is selectably directed through the three-way coolant valve  38  to the RESS  12  and/or through the bypass passage  40 , depending on the heating needs of the RESS  12 . When heating of both the cabin and the RESS  12  are required, RESS  12  heating will be limited, otherwise the RESS  12  will act as a heat sink and pull in all of the flow of coolant to the RESS  12 . 
     Referring now to  FIG.  3   , shown is a second operating mode, RESS heating mode, of the HVAC system  10 . This second mode is utilized in cold conditions, for example, when the ambient temperature is less than −10 degrees Celsius, and one or more of the RESS  12  or the cabin is requesting heating, with the cabin being heated via the heater core  14 . In RESS heating mode, the outside expansion valve  32  and the evaporator expansion valve  34  are closed, as is the outside heat exchanger valve  52 . The chiller expansion valve  36  is opened, so that in the refrigerant circuit  22  the flow of refrigerant leaves the compressor  24  and is directed through the internal condenser  20 , and then through the chiller expansion valve  36  and the chiller heat exchanger  30  before flowing back to the compressor  24 . 
     In the coolant loop  16 , thermal energy is exchanged between the flow of coolant and the flow of refrigerant at the internal condenser  20 . The heated flow of coolant then flows through the heater core  14  and is selectably directed through the three-way coolant valve  38  to the RESS  12  and/or through the bypass passage  40 , depending on the heating needs of the RESS  12 . When heating of both the cabin and the RESS  12  are required, RESS  12  heating will be limited, otherwise the RESS  12  will act as a heat sink and pull in all of the flow of coolant to the RESS  12 . 
     The use of the three-way coolant valve  38  allows modulation of the flow of coolant through the chiller heat exchanger  30  and the RESS  12 , such that the RESS  12  may be heated by the flow of coolant that is waste heat not utilized by the heater core  14  for cabin heating. 
     While the above disclosure has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from its scope. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiments disclosed, but will include all embodiments falling within the scope thereof.