EV Battery Cooling via CO2 Refrigerant Temperature Control
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Solution Overview
Problem
Rapid charging of electric vehicle batteries generates excessive heat, which existing thermal conditioning systems struggle to dissipate efficiently while minimizing energy consumption and system bulk, especially in high outside temperatures, and must be done concurrently with passenger compartment heating.
Innovation Solution
A method utilizing a natural refrigerant fluid circuit, such as carbon dioxide, with a first heat exchanger thermally coupled to the battery, where the refrigerant fluid's temperature is maintained between 15°C and 28°C, and pressure is increased to enhance cooling performance, allowing for efficient heat dissipation and simultaneous passenger compartment heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If rapid charging is performed on the electrical storage device, then charging time is reduced, but heat generation increases requiring more intensive cooling
Solution Approach 1:
The system pre-charges capacitors before rapid charging begins, storing energy that will be used to drive the refrigerant circulation and heat exchanger operation during the high-power charging phase, enabling immediate cooling response without waiting for compressor warm-up
Solution Approach 2:
A heat transfer fluid circuit acts as an intermediary between the battery and refrigerant circuit, absorbing heat from the battery and transferring it to the refrigerant system, enabling efficient thermal coupling and heat removal during rapid charging
2Temperature
If cooling power is increased to handle rapid charging heat, then temperature control improves, but energy consumption increases
Solution Approach 1:
The system uses waste heat from the battery during rapid charging to drive the refrigeration cycle, where the heat itself provides the energy needed for cooling, reducing external power consumption and improving overall system efficiency
Solution Approach 2:
The system dynamically adjusts refrigerant pressure and temperature parameters, operating at elevated pressures (51-69 bar) and controlled temperatures (20-26°C) to optimize the thermodynamic efficiency of the cooling cycle during rapid charging conditions
3Productivity
If refrigerant pressure is increased to improve cooling performance, then cooling efficiency increases, but system complexity increases
Solution Approach 1:
The refrigerant circuit is designed to serve multiple functions: cooling the battery during rapid charging, providing ambient air conditioning, and managing thermal loads under various operating conditions, reducing the need for separate dedicated cooling systems
Solution Approach 2:
The system uses high-pressure refrigerant circulation (51-69 bar) with controlled flow rates to achieve efficient heat transfer, utilizing fluid dynamics and pressure-driven flow to optimize cooling performance without mechanical complexity
4Temperature
If cooling system is designed for rapid charging conditions, then battery cooling performance improves, but passenger compartment heating capability may be compromised
Solution Approach 1:
The thermal conditioning system is designed to simultaneously or alternately provide battery cooling during rapid charging and passenger compartment heating/cooling, using a single integrated refrigerant circuit that can be dynamically controlled to meet different thermal demands
Solution Approach 2:
The system dynamically adjusts refrigerant flow distribution, heat exchanger operation, and circulation rates to adapt to changing thermal requirements, switching between battery-cooling-dominated and passenger-compartment-comfort-dominated modes as needed
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
The method effectively cools the battery during rapid charging by maintaining optimal refrigerant fluid temperatures and pressures, ensuring efficient thermal management and energy balance, even in extreme conditions.
Implementation Method 1
a first heat exchanger (4) thermally coupled to said electrical storage device (2), in which a refrigerant fluid (FR) circulates
Implementation Method 2
The invention takes advantage of the behavior of the natural refrigerant fluid, such as carbon dioxide, to allow an increase in the level of the low pressure
Implementation Method 3
a maintenance of a low pressure of the refrigerant fluid inside the first heat exchanger which is higher than a low pressure of the prior art
Data Source
Figure 1~2
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AI summary
The invention relates to a method for cooling an electrical storage device by means of a coolant circuit, inside which a natural coolant circulates, in particular carbon dioxide. The coolant circuit comprises at least one first heat exchanger thermally coupled to the electrical storage device. The cooling method comprises at least: - a first step (E1) of determining a fast charging state of the electrical storage device; - a second step (E2) of determining a thermal power to be extracted from the electrical storage device until the electrical storage device is charged beyond a determined threshold; - a third step (E3) of measuring a temperature of the electrical storage device; - a fourth step (E4) of adjusting a circulation of the coolant inside the first heat exchanger so that a coolant temperature is between 15°C and 28°C.