Patent Publication Number: US-2023142706-A1

Title: Vehicle cabin and rechargeable energy storage system thermal management system

Description:
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 the RESS to maintain performance. This heating is typically achieved via a separate cooling heater connected to the system. This separate cooling heater adds complexity to the system and increases energy usage of the system to provide heating of the RESS. 
     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 internal condenser, a heater core, and a rechargeable energy storage system (RESS). The refrigerant circuit and the coolant circuit exchange thermal energy at the internal condenser. When operated in an HVAC operating mode, the HVAC system is configured to heat one or more of the heater core and the RESS with thermal energy generated at the compressor. 
     Additionally or alternatively, in this or other embodiments in the HVAC operating mode, the HVAC system is configured to heat one or more of the heater core and the RESS with only thermal energy generated at the compressor. 
     Additionally or alternatively, in this or other embodiments the flow of coolant is selectably flowed through the chiller heat exchanger to exchange thermal energy with the flow of coolant at the chiller heat exchanger. 
     Additionally or alternatively, in this or other embodiments the coolant circuit includes a chiller coolant bypass valve to selectably direct the flow of coolant along a chiller coolant bypass passage or through the chiller heat exchanger. 
     Additionally or alternatively, in this or other embodiments the HVAC operating mode is engaged when an ambient air temperature is less than −10 degrees Celsius. 
     Additionally or alternatively, in this or other embodiments a pump urges circulation of 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. 
     Additionally or alternatively, in this or other embodiments the refrigerant circuit includes an outside heat exchanger fluidly connected to the internal condenser and the compressor. 
     Additionally or alternatively, in this or other embodiments when the HVAC system is operated in a heat pump mode, the flow of refrigerant is directed through the outside heat exchanger to absorb thermal energy from ambient air, 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 engaged when an ambient air temperature is greater than −10 degrees Celsius. 
     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 and thermal energy is exchanged between the flow of refrigerant and the flow of coolant at the internal heat condenser. One or more of the heater core and the RESS is heated via the flow of coolant. 
     Additionally or alternatively, in this or other embodiments in an HVAC operating mode heating one or more of the heater core and the RESS with only thermal energy generated at the compressor. 
     Additionally or alternatively, in this or other embodiments the HVAC operating mode is engaged when an ambient air temperature is less than −10 degrees Celsius. 
     Additionally or alternatively, in this or other embodiments the flow of coolant is selectably flowed through the chiller heat exchanger to exchange thermal energy with the flow of coolant at the chiller heat exchanger. 
     Additionally or alternatively, in this or other embodiments the coolant circuit includes a chiller coolant bypass valve to selectably direct the flow of coolant along a chiller coolant bypass passage or through the chiller heat exchanger. 
     Additionally or alternatively, in this or other embodiments an outside heat exchanger is located in the refrigerant circuit and is fluidly connected to the internal condenser and the compressor. 
     Additionally or alternatively, in this or other embodiments when in a heat pump mode, the flow of refrigerant is directed through the outside heat exchanger to absorb thermal energy from ambient air, bypassing the chiller heat exchanger. 
     Additionally or alternatively, in this or other embodiments the heat pump mode is engaged when an ambient air temperature is greater than −10 degrees Celsius. 
     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; 
         FIG.  3    is a schematic illustration of another operating mode of an HVAC system; 
         FIG.  4    is a schematic illustration of yet another operating mode of an HVAC system; 
         FIG.  5    is a schematic illustration of still another operating mode of an HVAC system; and 
         FIG.  6    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 . 
     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 , as well as 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 RESS bypass valve  38  to selectably direct the flow of coolant along a RESS bypass passage  40  or through the RESS  12 , a chiller coolant bypass valve  42  to selectably direct the flow of coolant along a chiller coolant bypass passage  44  or through the chiller heat exchanger  30 , an internal condenser bypass valve  46  to selectably direct the flow of coolant along an internal condenser coolant bypass passage  48  or through the internal condenser  20 , and a coolant four-way valve  50  upstream of the coolant pump  18 . The other two connections on the coolant four-way valve  50  are connected to a power electronics coolant loop  56 , which in some embodiments includes an associated low temperature radiator (not shown). The coolant four-way valve  50  can be operated in split mode where the coolant flow through the coolant circuit  16  and the power electronics coolant loop  56  is separated or in combined mode where the coolant flow through coolant circuit  16  and the power electronics coolant loop  56  is mixed. 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 of the HVAC system  10  is illustrated in  FIG.  2   . This first mode is utilized, for example, when the cabin is requesting heating via the heater core  14  and a target discharge temperature of the heater core  14  is greater than 50 degrees Celsius. In the first mode, the internal condenser refrigerant valve  54  is open, the outside heat exchanger valve  52  is closed, the outside expansion valve  32 , is closed, the evaporator expansion valve  34  is closed, and the chiller expansion valve  36  is opened. This directs the flow of refrigerant along the refrigerant circuit  22  through the compressor  24 , the internal condenser  20 , the chiller expansion valve  36 , the chiller heat exchanger  30  and back to the compressor  24 , bypassing the outside heat exchanger  26  and the evaporator  28 . In the coolant circuit  16 , the internal condenser bypass valve  46  is set to direct the coolant flow through the internal condenser  20 , and the chiller coolant bypass valve  42  is set to direct the flow of coolant through the chiller heat exchanger  30 , while the RESS bypass valve  38  is set to direct the flow of coolant along the RESS bypass passage  40 . Thus, the flow of coolant is directed along the coolant circuit  16  from the pump  46  through the internal condenser  20 , the heater core  14  and the chiller heat exchanger  30 . The RESS bypass valve  38  directs the flow of coolant along the RESS bypass passage  40  thus bypassing the RESS  12  before being directed back to the pump  18 . The cabin is thus heated by the heater core  14  by the heat of compression from the compressor  24 , without the introduction of outside ambient air for heat removal from the RESS  12 . 
     If, on the other hand, the target discharge temperature of the heater core  14  not greater than 50 degrees Celsius, the HVAC system  10  is operated in a second mode where the valves  38 ,  42  and  46  are modulated to provide the desired amount of heating to the heater core  14 , as illustrated in  FIG.  3   . In the second mode, the chiller coolant bypass valve  42  is selectably or partially opened to modulate flow of coolant through the chiller heat exchanger  30  and the chiller coolant bypass passage  44 . Similarly, the RESS bypass valve  38  is partially or selectably opened to modulate the flow of coolant along the RESS bypass passage  40  and through the RESS  12 . The internal condenser bypass valve  46  is similarly selectably or partially opened to modulate the flow of coolant along the internal condenser coolant bypass passage  48  or through the internal condenser  20 . This modulation of the valves  38 ,  42  and  46  provides the desired amount of heating to the heater core  14 . 
     Referring now to  FIG.  4   , in a third mode the internal condenser bypass valve  46  is set to direct the coolant flow through the internal condenser  20 , and the chiller coolant bypass valve  42  is set to direct the flow of coolant through the chiller heat exchanger  30 , while the RESS bypass valve  38  is set to direct the flow of coolant through the RESS  12 . Thus, the flow of coolant is directed along the coolant circuit  16  from the pump  18  through the internal condenser  20 , the heater core  14  and the chiller heat exchanger  30 . The RESS bypass valve  38  directs the flow of coolant through the RESS  12  before being directed back to the pump  18 . The cabin is thus heated by the heater core  14 , and the RESS  12  is heated by the heat of compression from the compressor  24 , without the introduction of outside ambient air for heat removal from the RESS  12 . 
     The valve and flow configuration shown in  FIG.  4    may also be utilized to operate the HVAC system  10  in a fourth mode, where waste heat from the RESS  12  is utilized to further provide heat to the heater core  14  for cabin heating. This mode may be utilized when the ambient temperature is very low, for example, less than −10 degrees Celsius and the temperature of the RESS  12  is relatively high, such as greater than 10 degrees Celsius. 
     In some embodiments, such as when the ambient temperature is greater than −10 degrees Celsius, the HVAC system  10  operates as a heat pump, drawing heat from outside air via the outside heat exchanger  26 . Referring now to  FIG.  5   , when the ambient temperature is greater than −10 degrees Celsius, and the target discharge temperature of the heater core  14  is greater than 50 degrees Celsius, the HVAC system  10  operates in a fifth mode. In this fifth mode, the internal condenser refrigerant valve  54  is opened and the outside heat exchanger refrigerant valve  52  is closed. The outside heat exchanger expansion valve  32  is opened, and both the evaporator expansion valve  34  and the chiller expansion valve  36  are closed. Thus, in the refrigerant circuit  22  the refrigerant flows from the compressor  24  through the internal condenser  20  and then through the outside heat exchanger  26  which acts as an evaporator by exchanging thermal energy with outside air. From the outside heat exchanger  26 , the refrigerant returns to the compressor  24 . In the coolant circuit  16 , the coolant valves  38 ,  42 ,  46  and  50  are set to direct the flow of coolant from the pump  18  and through the internal condenser  20  and then the heater core  14 . The flow of coolant then bypasses the chiller heat exchanger  30  and the RESS  12  as directed by valves  38  and  42 . From the RESS bypass passage  40 , the flow of coolant then returns to the pump  18 . 
     In another embodiment, illustrated in  FIG.  6   , the HVAC system  10  operates in a sixth mode, where the RESS  12  requires heating. In this mode, in the coolant circuit  16 , the coolant valves  38 ,  42 ,  46  and  50  are set to direct the flow of coolant from the pump  18  and through the internal condenser  20  and then the heater core  14 . The flow of coolant then flows through the chiller heat exchanger  30  and the RESS  12  as directed by valves  38  and  42 . From the RESS  12 , the flow of coolant then returns to the pump  18 . 
     The HVAC system  10  described herein utilizes the refrigerant circuit  22  to heat the cabin via the heater core  14  and the RESS  12  by utilizing only compressor  24  power, and not utilizing a typical coolant heater in cold weather (less than −10 degrees Celsius). This is accomplished by routing the flow of coolant in the coolant circuit  16  through the internal condenser  20  and the heater core  14 . The system  10  can also be operated to pull heat from ambient when the ambient temperature is higher, thus saving energy usage. 
     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.