EV HVAC System Battery Thermal Management
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Solution Overview
Problem
Electric vehicles face reduced driving distances due to inefficient energy management for both indoor heating and battery temperature control, leading to suboptimal performance and voltage output, especially in winter conditions.
Innovation Solution
A Heating, Ventilation, and Air Conditioning (HVAC) system for vehicles that includes a battery circulation line with a radiator and a branch line for cooling, a battery heating line with a water heater and indoor air conditioning heater core, and a controller to manage coolant flow for simultaneous or separate heating and cooling of the high-voltage battery and indoor space, optimizing energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If two independent cooling and heating systems are employed (one for indoor air conditioning and another for battery temperature control), then the battery module can be maintained in an optimal temperature environment, but energy management becomes inefficient and driving distance is reduced
Solution Approach 1:
The patent merges the indoor air conditioning system and the battery temperature control system into a single integrated HVAC system. The system uses a common refrigerant circulation path where the refrigerant can serve dual purposes: cooling the indoor cabin through the evaporator and cooling the battery through a battery cooling heat exchanger. This integration allows the system to manage both indoor temperature and battery temperature using one refrigerant cycle, thereby improving energy management efficiency while maintaining optimal battery temperature.
Solution Approach 2:
The refrigerant circulation system is designed to perform multiple functions simultaneously. The same refrigerant loop that provides air conditioning for the cabin also provides cooling for the battery through selective heat exchange. The system can operate in different modes (indoor cooling only, battery cooling only, or both simultaneously) by controlling valve positions, allowing one system to universally handle both thermal management requirements.
2Temperature
If separate electric coolant heating type heater is used for indoor heating and battery temperature control, then both indoor space and battery can be heated in winter, but energy consumption increases significantly and driving distance is reduced by 40% or more
Solution Approach 1:
The system converts the waste heat generated by the refrigerant condenser into a useful resource for heating. During heating mode, the refrigerant absorbs heat from the outdoor air through the heat pump compressor and condenser, and this high-temperature refrigerant then transfers heat to the battery and/or indoor cabin through the heater core and battery heating heat exchanger. This approach converts what would otherwise be waste heat into beneficial thermal energy for both battery and cabin heating, significantly reducing energy consumption compared to using separate electric heaters.
Solution Approach 2:
The heating system integrates battery heating and indoor cabin heating into a single thermal management pathway. The refrigerant flows through a series of heat exchange components (heat pump compressor, condenser, heater core, battery heating heat exchanger) that can simultaneously or selectively heat both the battery and the indoor space. This merged heating system allows thermal energy to be efficiently distributed to both destinations through controlled refrigerant flow, reducing the total energy required compared to separate heating systems.
3Temperature
If high-voltage battery is cooled by outdoor temperature during winter running, then the battery operates in cold conditions, but the battery fails to reach proper temperature and outputs lowered voltage
Solution Approach 1:
The system addresses the winter cold temperature problem by using the heat pump refrigeration cycle to actively heat the battery. The refrigerant, after being compressed and heated in the condenser, flows through the battery heating heat exchanger where it transfers thermal energy to the battery. This converts the harmful cold outdoor temperature into a controlled heating process, ensuring the battery reaches its optimal operating temperature range and maintains proper voltage output during winter operation.
Solution Approach 2:
The refrigerant acts as an intermediary heat transfer medium between the outdoor environment and the battery. Through the heat pump cycle, the refrigerant absorbs heat from the outdoor air (even in cold conditions) and delivers it to the battery through the battery heating heat exchanger. This intermediary mechanism allows the battery to be heated efficiently without direct exposure to cold outdoor temperatures, maintaining reliable voltage output.
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 reduces energy consumption and extends driving distance by efficiently managing energy for both indoor heating and battery temperature, ensuring optimal performance and voltage output.
Implementation Method 1
a cooling heat exchanger configured to exchange heat with an indoor air conditioning refrigerant line
Implementation Method 2
a battery heating line including a water heater, an indoor air conditioning heater core
Implementation Method 3
an indoor air conditioning heater core
Implementation Method 4
a battery circulation line including a battery radiator
Data Source
AI summary
A vehicular HVAC system, includes: a battery circulation line including a battery radiator, a high-voltage battery, and a first valve, arranged to allow a first coolant to circulate therethrough; a branch line selectively connected to the circulation line through the valve and having a cooling heat exchanger configured to exchange heat with an indoor air conditioning refrigerant line; a battery heating line including a water heater, an indoor air conditioning heater core, and a second valve, arranged to allow a second coolant to circulate therethrough, the battery heating line being selectively connected to the circulation line through the second valve; and a controller configured to control the first valve in stages, to cool the high-voltage battery, to control the second valve and the water heater to selectively heat the battery, and to control the water heater or a cooling device on the refrigerant line to air condition the vehicle.