Phase-Change Thermal Battery for EV Cabin Heating Range Loss
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Solution Overview
Problem
Electric vehicles face challenges in heating their occupant cabins efficiently due to limited waste heat generation, especially at low ambient temperatures, which can reduce the vehicle's driving range when electric heating is used, and conventional heat pumps are ineffective with commonly used refrigerants.
Innovation Solution
A thermal battery system comprising a thermal core with a phase change material, a housing, and a heat transfer assembly that circulates a fluidic medium to extract and release thermal energy, using a heat exchanger and a vacuum pump to manage thermal energy efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If electric heating is used to warm the cabin, then the heating function is achieved, but the driving range of the vehicle is drastically reduced due to high electrical power consumption from the traction battery
Solution Approach 1:
The thermal battery is pre-charged with thermal energy at charging stations before the vehicle is operated. This preliminary storage of thermal energy allows the cabin to be heated without consuming electrical power during vehicle operation, thus maintaining driving range while achieving heating function.
Solution Approach 2:
The thermal battery acts as an intermediary energy storage device between the charging infrastructure and the cabin heating system. It decouples the heating function from direct electrical power consumption by storing thermal energy during charging and releasing it during operation.
2Adaptability or versatility
If a heat pump with commonly used refrigerants (R134a, R1234yf) is used, then the heating system can operate, but it is unsatisfactory at ambient temperatures below 0°C because the refrigerant cannot physically exist as a low temperature vapour at high enough pressure to deliver satisfactory heating power
Solution Approach 1:
The invention changes the operating parameters of the heating system by using a thermal battery that can store and release thermal energy at temperatures suitable for cabin heating, bypassing the limitations of refrigerant-based heat pumps at sub-zero ambient temperatures.
3Reliability
If the thermal battery uses a thermally conductive container and compartments to store phase change material, then thermal energy storage efficiency is improved, but the device complexity increases due to the array of compartments and thermal connection requirements
Solution Approach 1:
The thermal battery is divided into multiple compartments that can be independently filled with phase change material. Each compartment is thermally connected to the container wall, allowing modular construction and efficient thermal energy storage while maintaining manageable complexity through standardized modular units.
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
Provides a reliable, non-intermittent heat source for electric vehicles that does not consume significant electrical power, effectively warming the cabin and extending the vehicle's range by storing and releasing thermal energy as needed.
Implementation Method 1
phase change material received in the core interior and configured to store and release the thermal energy
Implementation Method 2
a heat transfer assembly for circulating a fluidic heat transfer medium to extract heat from the thermal core
Implementation Method 3
a plurality of heating devices supported in the core interior and in thermal contact with the array of compartments, wherein the heating devices are configured to apply thermal energy to the phase change material for storage therein
Data Source
AI summary
A thermal battery and related method of use comprises a thermal core configured to store and release thermal energy, a housing having an enclosed interior receiving the thermal core therein and a heat exchanger inside the housing and configured to (i) circulate a heat transfer medium around the core and (ii) extract thermal energy from the heat transfer medium for release outside the thermal battery. Ducting inside the housing fluidically interconnects the heat exchanger and a space around the core. The core comprises an enclosed container with thermally conductive outer walls, a phase change material received therein, an array of compartments defining substantially separate volumes receiving the phase change material and thermally connected to the outer walls of the container, and heating devices in the core and in thermal contact with the compartments for heating the phase change material.