Thermal Battery Defogging for Electric Vehicle Windows
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Solution Overview
Problem
Electric and hybrid vehicles face challenges in defrosting/demisting without relying on battery energy, as conventional air conditioning systems are not optimized for energy efficiency in these powertrains, leading to reduced autonomy and increased energy consumption.
Innovation Solution
A demisting and de-icing device utilizing a thermal battery with a phase change material and thermoelectric cooling, allowing for independent operation and minimal energy draw from batteries, featuring a three-way valve for selective fluid circulation and a heat exchanger for efficient cold storage and release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional air conditioning system is used for defrosting/demisting in electric vehicles, then the defrosting function is achieved, but the battery energy is depleted and autonomy is reduced
Solution Approach 1:
The system pre-cools a thermal storage medium (water or salt solution) in the thermal battery during periods when defrosting is not needed, storing cold energy for later use. This preliminary cooling action allows the system to provide defrosting function without consuming battery energy at the moment of need, thus resolving the contradiction between maintaining defrosting reliability and reducing battery energy consumption.
Solution Approach 2:
The invention changes the temperature parameter of the thermal storage medium by freezing water or cooling salt solutions to sub-ambient temperatures, storing this cold energy in the thermal battery. This parameter change enables the system to later release stored cold for defrosting without requiring active cooling or battery power, thus achieving defrosting function while minimizing battery energy consumption.
2Reliability
If a conventional refrigeration system is installed for defrosting/demisting, then the cooling function is provided, but the system size and complexity increase
Solution Approach 1:
The thermal battery system is designed to serve multiple functions: it stores cold energy for defrosting/demisting, can pre-cool air for passenger comfort, and integrates with the vehicle's existing HVAC system. This multi-functionality allows a single system to replace or supplement conventional refrigeration systems, providing cooling functions while reducing overall system size and complexity.
Solution Approach 2:
The system utilizes phase transition of water (liquid to solid) or temperature changes in salt solutions to store and release cold energy. By leveraging these natural phase transitions and thermal properties, the system achieves efficient cold storage without requiring large mechanical refrigeration components, thus providing the necessary cooling function with reduced system size and complexity.
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
Enables defrosting/demisting without depleting battery energy, enhancing vehicle autonomy by using external power sources during shutdown and leveraging stored cold for efficient cooling, reducing energy consumption and system size compared to conventional refrigeration systems.
Implementation Method 1
the thermal battery comprises a phase change material whose phase change temperature is between 0 and - 5°C
Implementation Method 2
the phase change material is a eutectic whose latent heat of phase change is greater than or equal to 300 kJ/kg
Implementation Method 3
the cooling means are thermoelectric cooling devices
Implementation Method 4
a heat exchanger for efficient cold storage and release
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a device and method for defogging and/or de-icing a window of a motor vehicle having a partially or fully electric drive system. According to the invention, the device comprises means (1) for cooling a cooling fluid, from at least one electric current source, and a thermal battery (2). The device is configured such that: during certain phases, the cooling fluid can be cooled by the cooling means (1) and cold from the cooling fluid can be stored in the battery (2); and, during other phases, cold can be released from the battery (2) into the cooling fluid.