EV Battery Thermal Fluid Heating for Low-Temperature Circulation
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Solution Overview
Problem
The viscosity of dielectric thermal fluids used in battery thermal management systems for electric vehicles increases at low temperatures, leading to inefficient fluid circulation and potential component wear, particularly in hybrid electric engines.
Innovation Solution
A thermal management system with multiple fluid circuits, including a primary system with a thermal fluid tank, electric heater, and heat exchangers, and a secondary system that utilizes a common driver for both fluid pumps, allowing selective operation of the second fluid pump based on ambient temperature conditions to optimize heating efficiency 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 achieved, but viscosity increases at low temperatures causing circulation inefficiency
Solution Approach 1:
The system performs preliminary heating of the dielectric thermal fluid using an electric heater before the fluid circulates through the battery. This pre-heating action reduces the fluid's viscosity in advance, ensuring efficient circulation while maintaining electrical non-conductivity throughout operation.
Solution Approach 2:
The system changes the temperature parameter of the dielectric thermal fluid by incorporating an electric heater and heat exchangers. By controlling the fluid temperature above freezing points and maintaining optimal operating ranges, the system reduces viscosity while preserving electrical insulation properties.
2Temperature
If high viscosity thermal fluid is circulated at low temperatures, then battery warming is achieved, but pump wear increases and energy consumption rises
Solution Approach 1:
The electric heater performs preliminary heating of the thermal fluid before it reaches the pump and battery. This preliminary thermal treatment reduces fluid viscosity, allowing the pump to operate more efficiently with lower energy consumption while still achieving the required battery warming effect.
Solution Approach 2:
The system introduces an intermediary heating mechanism (electric heater and heat exchangers) between the power source and the battery. This intermediary component pre-heats the thermal fluid, reducing its viscosity and thereby decreasing the energy required by the pump to circulate the fluid, while still achieving effective battery warming.
3Productivity
If multiple fluid circuits are used for selective heating, then heating efficiency is improved, but system complexity increases
Solution Approach 1:
The thermal management system is segmented into multiple independent fluid circuits, each with its own pump and heat exchanger. This segmentation allows selective operation of individual circuits based on temperature requirements, improving heating efficiency while enabling simplified control strategies for managing system complexity.
Solution Approach 2:
The system employs dynamic control where pumps and heat exchangers can be selectively activated or deactivated based on real-time temperature conditions. This dynamic operation allows the system to maintain high heating efficiency when needed while reducing complexity and energy consumption during normal operating conditions.
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 both the battery and operator cab, reduces energy consumption by using a single driver for dual pumps, and maintains efficient fluid circulation by adjusting pump operation based on temperature needs, thereby enhancing the operational efficiency and longevity of the thermal management system.
Implementation Method 1
a second fluid circuit having an electric heater
Implementation Method 2
a first heat exchanger positioned to be submerged within the first thermal fluid in the thermal fluid tank
Implementation Method 3
at least a portion of a heat entrained in the second thermal fluid can be transferred to at least a portion of the first thermal fluid
Implementation Method 4
a second heat exchanger positioned between the first heat exchanger and the electric heater
Implementation Method 5
at least a portion of the heat remaining in the second thermal fluid can be transferred to provide heat for the operator cab
Data Source
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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.