High-Voltage Battery Cooling With Depressurized Two-Phase Heat Rejection
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Solution Overview
Problem
High-voltage batteries in motor vehicles face challenges in heat dissipation due to the limited heat capacity of dielectric media, which often requires high volume flow rates, and existing fluorine-based dielectric coolants pose health and environmental concerns, along with safety risks from phase transitions and pressure increases.
Innovation Solution
A cooling system comprising a first single-phase cooling circuit for direct cooling of the battery cell module and a second depressurized two-phase cooling circuit with a fluorine-free medium, utilizing phase-change materials like salts, paraffins, or glycol compounds, and a hybrid heat exchanger design for efficient heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fluorine-based dielectric coolants are used for direct cooling, then heat dissipation effectiveness is improved, but health and environmental safety deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the cooling medium by using fluorine-free dielectric coolants (such as hydrocarbons, esters, or etheres) instead of traditional fluorinated compounds. This parameter change maintains the dielectric properties needed for direct cooling while eliminating the harmful fluorinated substances, thus resolving the contradiction between heat dissipation effectiveness and environmental safety.
2Quantity of substance
If two-phase cooling media with phase transition are used, then heat capacity is improved, but safety deteriorates due to pressure increase
Solution Approach 1:
The patent utilizes phase transition phenomena of fluorine-free dielectric cooling media to achieve high heat capacity during the cooling process. By carefully selecting substances with appropriate phase transition temperatures and pressures, the system captures large amounts of heat during phase change while maintaining safe operating pressure levels, thus resolving the contradiction between heat capacity and safety.
3Productivity
If high volume flow rates are used to compensate for limited heat capacity, then heat dissipation is improved, but device complexity and energy costs worsen
Solution Approach 1:
The patent changes the thermal properties parameter of the cooling medium by selecting dielectric fluids with inherently high heat capacity. This parameter change allows the system to achieve effective heat dissipation at lower volume flow rates, thereby reducing pump power requirements and system complexity while maintaining high productivity in heat removal.
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 quick and effective heat dissipation without health, environmental, or safety concerns, using fluorine-free two-phase cooling media that would not be usable at atmospheric pressure, reducing design and energy costs while ensuring safe operation.
Implementation Method 1
direct cooling via dielectric media has now established itself, which is applied directly to the cells and can dissipate larger amounts of heat in a short time by direct contact
Implementation Method 2
special dielectric coolants have been developed that have a high heat capacity in a phase transition, wherein the high heat capacity can be utilized for effective cooling
Implementation Method 3
the known special dielectric coolants are exclusively substances that contain fluorine, which prohibits their use in vehicles in view of the current discussion on perfluorinated and polyfluorinated alkyl substances
Implementation Method 4
an ambient heat exchanger configured for delivery of thermal energy of the single-phase cooling medium to an environment
Data Source
AI summary
A cooling system for cooling a high-voltage battery in a motor vehicle, the system including a first cooling circuit having a single-phase cooling medium configured for direct cooling of a cell module of the high-voltage battery and an ambient heat exchanger configured for delivery of thermal energy of the single-phase cooling medium to an environment. The cooling system further includes a second cooling circuit having a two-phase cooling medium, an ambient heat exchanger configured for delivering thermal energy of the two-phase cooling medium to the environment and a further heat exchanger configured for receiving thermal energy of the single-phase cooling medium. The two-phase cooling medium is fluorine-free, and the second cooling circuit is depressurized.