Battery Thermal Fluid Preheating for Low-Temperature Circulation
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Solution Overview
Problem
The high viscosity of dielectric thermal fluids at low temperatures in battery thermal management systems of electric vehicles can hinder fluid circulation, leading to premature wear of pumps and reduced efficiency, particularly in hybrid electric engines.
Innovation Solution
A thermal management system with a primary fluid circuit using an electric heater to heat a first thermal fluid, a secondary fluid circuit for heating an operator cab, and a third fluid circuit utilizing external thermal fluid from another system, combined with a dual-pump arrangement and clutch mechanism to optimize heating and reduce energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dielectric thermal fluid is used for battery thermal management, then electrical non-conductivity is improved, but viscosity at low temperatures increases causing circulation problems
Solution Approach 1:
The system performs preliminary heating of the dielectric thermal fluid using an electric heater before the fluid is circulated through the battery system. This pre-heating action reduces the fluid's viscosity to acceptable levels, enabling proper circulation while maintaining the electrical non-conductivity property throughout operation.
Solution Approach 2:
The system changes the temperature parameter of the dielectric thermal fluid by implementing a heating system that raises the fluid temperature above freezing points. This parameter change transforms the fluid from a high-viscosity state at low temperatures to a low-viscosity state at elevated temperatures, solving the circulation problem while preserving electrical insulation properties.
2Temperature
If electric heater is used to heat thermal fluid, then warming capability is improved, but energy consumption increases
Solution Approach 1:
The thermal management system is designed to perform multiple functions: it can heat the dielectric thermal fluid using the electric heater when needed, and it can also utilize waste heat from the battery system or engine coolant through heat exchangers. This multi-functionality reduces reliance on the electric heater alone, thereby lowering energy consumption while maintaining the required temperature levels.
Solution Approach 2:
The system converts waste heat that would otherwise be discarded into a useful resource for heating the dielectric thermal fluid. By incorporating heat exchangers that transfer heat from the battery system or engine coolant to the thermal fluid, the system transforms potentially harmful waste heat into a beneficial heating source, reducing the need for additional energy input from the electric heater.
3Ease of operation
If thermal fluid viscosity is reduced by heating, then fluid circulation is improved, but pump wear increases
Solution Approach 1:
The system applies preliminary heating to the dielectric thermal fluid before it enters the pump and circulation system. By pre-heating the fluid to reduce its viscosity, the pump operates under more favorable conditions with reduced mechanical stress and wear, thereby extending pump lifespan while maintaining improved fluid circulation.
Solution Approach 2:
The system changes the temperature parameter of the thermal fluid to optimize both circulation and pump durability. By maintaining the fluid at elevated temperatures where viscosity is reduced, the system achieves better circulation while simultaneously reducing the mechanical load on pump components, thus extending their operational life.
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 system effectively heats the battery and operator cab while minimizing energy use and reducing pump wear, maintaining efficient fluid circulation across varying ambient temperatures.
Implementation Method 1
a second fluid circuit having an electric heater, a first heat exchanger, and a second heat exchanger
Implementation Method 2
The first heat exchanger can be positioned to be submerged within the first thermal fluid in the thermal fluid tank
Implementation Method 3
The second heat exchanger can be positioned between the first heat exchanger and the electric heater
Data Source
AI summary
Systems and methods for warming a battery and operator cab of an electric vehicle. A second thermal fluid is circulated in a second fluid circuit of a primary system, and is heated by an electric heater before being circulated to a first heat exchanger to heat a first thermal fluid in a fluid thermal tank. The heated first thermal fluid is circulated via a first fluid circuit of the primary system and to the battery, or selectively bypasses the battery and returns to the fluid thermal tank. Occasionally, an external system is coupled to a portion of a third fluid circuit residing in the primary system such that heated third thermal fluid from the external system flows to the first heat exchanger. Partially heated second or third thermal fluid can flow to a second heat exchanger such that the remaining heat entrained therein can heat the operator cab.