Vehicular Air Conditioning Battery Cooling via Refrigerant Heat Exchange
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Solution Overview
Problem
Conventional air conditioning systems for vehicles, particularly hybrid and electric vehicles, face inefficiencies in cooling battery temperatures due to lag in compressor control and heat capacity of the cooling medium, leading to wasteful power consumption and temperature fluctuations.
Innovation Solution
A vehicular air conditioning device with a refrigerant circuit that includes a compressor, heat exchangers, and a control device, which uses a refrigerant-heat medium heat exchanger to adjust battery temperature by controlling the compressor or expansion valve based on the refrigerant temperature, ensuring precise and efficient cooling by decompressing refrigerant to flow into the heat exchanger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the compressor is controlled based on the temperature of cooling water circulated in the battery temperature adjustment device, then the battery temperature can be adjusted, but control lag occurs due to heat capacity of the cooling water and pipe
Solution Approach 1:
The patent introduces a refrigerant-heat medium heat exchanger as an intermediary component between the refrigerant circuit and the battery temperature adjustment device. This heat exchanger allows indirect heat exchange between the refrigerant and the cooling water, enabling the compressor to be controlled based on refrigerant temperature rather than cooling water temperature, thereby eliminating control lag while still achieving battery temperature adjustment.
Solution Approach 2:
The system performs preliminary cooling action by controlling the refrigerant temperature in the refrigerant-heat medium heat exchanger before the cooling water temperature needs to change. Since the refrigerant can be quickly cooled by the expansion valve and compressor, the cooling water is pre-cooled through heat exchange, eliminating the lag that would occur if waiting for water temperature to respond to compressor control.
2Productivity
If the compressor control amount is increased to overcome control lag, then temperature adjustment speed improves, but wasteful power consumption increases
Solution Approach 1:
The expansion valve performs preliminary cooling of the refrigerant before it enters the refrigerant-heat medium heat exchanger. This pre-cooled refrigerant then efficiently transfers heat to the cooling water, achieving fast temperature adjustment without requiring the compressor to work at high power levels, thus avoiding wasteful energy consumption.
Solution Approach 2:
The refrigerant-heat medium heat exchanger acts as an efficient heat transfer intermediary that accelerates the cooling process. By using the refrigerant's phase change and heat exchange properties in this dedicated heat exchanger, the system achieves rapid battery temperature adjustment without excessive compressor power consumption.
3Reliability
If the cooling water temperature is monitored and compressor control is adjusted, then battery cooling is achieved, but temperature fluctuations and oscillations occur
Solution Approach 1:
The refrigerant-heat medium heat exchanger serves as a stabilizing intermediary that decouples the compressor control from direct battery temperature monitoring. The control system now regulates based on refrigerant temperature in the heat exchanger, which responds quickly and smoothly, preventing the oscillations that occur when directly controlling based on battery or cooling water temperature.
Solution Approach 2:
The system implements feedback control by monitoring the refrigerant temperature in the refrigerant-heat medium heat exchanger and adjusting the expansion valve and compressor accordingly. This feedback mechanism, combined with the thermal inertia of the heat exchanger and cooling water, creates a stable control system that prevents temperature oscillations while maintaining reliable battery cooling.
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
This solution eliminates lag in compressor control and reduces wasteful power consumption, allowing for accurate and efficient battery temperature adjustment, improving cooling efficiency and reducing temperature fluctuations.
Implementation Method 1
a refrigerant-heat medium heat exchanger to exchange heat between at least part of the refrigerant flowing out from the heat exchanger for heat radiation and the heat medium of the battery temperature adjustment device
Implementation Method 2
an expansion valve to decompress the refrigerant flowing into the refrigerant-heat medium heat exchanger
Implementation Method 3
a compressor to compress and discharge a refrigerant
Implementation Method 4
a radiator disposed on a vehicle interior side to let the refrigerant radiate heat
Implementation Method 5
a heat absorber disposed on the vehicle interior side to let the refrigerant absorb heat
Data Source
AI summary
A vehicular air conditioning device is provided which is capable of cooling a heat medium of a battery temperature adjustment device by a refrigerant in a refrigerant circuit to improve operation efficiency when a battery is to be cooled. The vehicular air conditioning device includes a battery temperature adjustment device (61) for circulating a heat medium in a battery (55) to cool the same, a refrigerant-heat medium heat exchanger (64) for exchanging heat between at least part of the refrigerant flowing out from an outdoor heat exchanger (7) and the heat medium circulating in the battery temperature adjustment device, and an auxiliary expansion valve (73) for decompressing the refrigerant flowing into the refrigerant-heat medium heat exchanger. A control device controls a compressor (2) or the auxiliary expansion valve on the basis of a temperature Tw of the refrigerant of the refrigerant-heat medium heat exchanger to thereby adjust a battery temperature Tb to a target battery temperature TBO.