Refrigerant-Coolant Heat Exchanger for High Capacity EV Cooling
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Solution Overview
Problem
Conventional motor vehicle cooling systems, particularly for electric and hybrid vehicles, face challenges in providing sufficient refrigerating capacity during quick charge processes, with existing systems limited to around 13-14 kW of heat release, whereas a requirement of 12-15 kW is needed, and this is exacerbated by reduced air flow when the vehicle is stationary, leading to inefficiencies and increased costs.
Innovation Solution
A system with a refrigerant circuit thermally coupled to a coolant circuit through a refrigerant-coolant heat exchanger, where the refrigerant circuit includes a refrigerant-air heat exchanger as a condenser/gas cooler and a coolant-air heat exchanger, allowing for efficient heat transfer and storage, enabling operation at high efficiency with minimal installation space and cost, and capable of handling refrigerating capacities up to 20 kW.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional cooling systems with single compressor and standard heat exchangers are used, then system complexity is kept low, but refrigerating capacity is insufficient (6-9 kW) for quick charge processes requiring 12-15 kW
Solution Approach 1:
The patent merges the coolant circuit and refrigerant circuit through a refrigerant-coolant heat exchanger, allowing the battery cooling function and air conditioning function to share common components. The refrigerant circuit serves dual purposes: cooling the battery directly and conditioning passenger compartment air, thereby achieving 12-15 kW refrigerating capacity without proportionally increasing system complexity
Solution Approach 2:
The refrigerant circuit is designed with multi-functionality to handle multiple cooling tasks simultaneously. The same refrigerant circuit with single compressor provides cooling for both the battery (through refrigerant-coolant heat exchanger) and the passenger compartment (through evaporator), enabling the system to deliver 12-15 kW total refrigerating capacity for quick charge processes while avoiding the need for separate dedicated cooling systems
2Power
If multiple compressors or independent refrigerant circuits are implemented to achieve high refrigerating capacity, then refrigerating capacity increases to 12-15 kW, but system complexity and cost increase significantly
Solution Approach 1:
The patent merges the coolant circuit and refrigerant circuit through a refrigerant-coolant heat exchanger, allowing the battery cooling function and air conditioning function to share common components. The refrigerant circuit serves dual purposes: cooling the battery directly and conditioning passenger compartment air, thereby achieving 12-15 kW refrigerating capacity without proportionally increasing system complexity
Solution Approach 2:
The refrigerant circuit is designed with multi-functionality to handle multiple cooling tasks simultaneously. The same refrigerant circuit with single compressor provides cooling for both the battery (through refrigerant-coolant heat exchanger) and the passenger compartment (through evaporator), enabling the system to deliver 12-15 kW total refrigerating capacity for quick charge processes while avoiding the need for separate dedicated cooling systems
3Productivity
If vehicle is stationary during quick charge, then charging speed is maintained, but air flow over heat exchangers is reduced, decreasing heat release efficiency
Solution Approach 1:
The refrigerant-coolant heat exchanger acts as an intermediary thermal storage medium. During stationary quick charging, the refrigerant circuit absorbs heat from the battery through the refrigerant-coolant heat exchanger and stores it temporarily in the refrigerant. When vehicle moves and air flow increases, the refrigerant efficiently releases the stored heat to the ambient air through the condenser, thus decoupling the charging process from the heat release efficiency
Solution Approach 2:
The refrigerant circuit performs preliminary heat absorption from the battery during the charging process, storing thermal energy in the refrigerant before final heat release to ambient. This preliminary action allows the system to prepare for efficient heat dissipation before the vehicle starts moving, ensuring that heat release efficiency is not compromised during stationary charging
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures adequate cooling during quick charge processes, reduces the need for large heat-releasing surfaces, and maintains system efficiency with minimal production and maintenance costs, while allowing for the use of various refrigerants like R134a, R744, and R1234yf.
Implementation Method 1
a refrigerant circuit (2) thermally coupled across a refrigerant-coolant heat exchanger (4) operated as condenser/gas cooler with a coolant circuit (12)
Implementation Method 2
a refrigerant-air heat exchanger (5) operated as condenser/gas cooler
Implementation Method 3
a refrigerant-air heat exchanger (5) operated as condenser/gas cooler
Implementation Method 4
at least one heat exchanger (7), operated as evaporator, for conditioning an air-mass flow to be supplied to the passenger compartment
Implementation Method 5
a coolant circuit (12) with a battery cooler (14) for tempering a battery
Data Source
AI summary
System and method for operating the system for climatizing air of a passenger compartment and for heat exchange with drive components of motor vehicles includes a coolant circuit and refrigerant circuit with a compressor, a refrigerant-air heat exchanger, operated as condenser/gas cooler, at least one expansion element, at least one heat exchanger, operated as evaporator, for conditioning an air-mass flow supplied to the passenger compartment; this is implemented as refrigerant-air heat exchanger, and at least one heat exchanger, operated as evaporator, which is implemented as refrigerant-coolant heat exchanger and disposed within the coolant circuit for heat transfer from coolant to refrigerant. The refrigerant circuit includes a heat exchanger, operated as condenser/gas cooler, which acts as refrigerant-coolant heat exchanger and is disposed within the coolant circuit for heat transfer from refrigerant to coolant. The coolant circuit is implemented with at least one heat exchanger for heat exchange with a drive component.