Refrigeration cycle device
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Solution Overview
Problem
The existing refrigeration cycle devices, such as those disclosed in Patent Document 1, cannot appropriately adjust the temperature of batteries in electric or hybrid vehicles to a range lower than that of air, which can lead to battery degradation due to high temperatures, reducing discharge efficiency and potentially making the battery unusable.
Innovation Solution
A refrigeration cycle device with a compressor, air heat exchanger, high-stage and low-stage decompressors, battery heat exchanger, exterior heat exchanger, and accumulator, allowing for adjustable temperature control of both air and batteries by varying the opening degree of the high-stage decompressor and controlling refrigerant flow, ensuring the battery temperature remains within a safe range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the refrigeration cycle device uses a single heat exchanger to heat both air and battery, then the device complexity is reduced, but the temperature control precision for the battery deteriorates
Solution Approach 1:
The single heat exchanger is segmented into two separate heat exchangers: a first heat exchanger for heating air and a second heat exchanger for heating the battery. This segmentation allows independent temperature control for each component, resolving the contradiction by enabling precise battery temperature control while maintaining reasonable device complexity through modular design.
Solution Approach 2:
Different heat exchangers are assigned to different components (air vs. battery) based on their specific thermal requirements. The second heat exchanger is specifically optimized for battery heating with controlled refrigerant flow, providing local quality enhancement for temperature control precision where it is most needed.
2Productivity
If the refrigerant pressure in the upstream heat exchanger is increased to improve air heating efficiency, then the air heating performance is improved, but the battery temperature becomes excessively high causing degradation
Solution Approach 1:
The refrigerant flow path is segmented into two separate heat exchangers with independent pressure control. The first heat exchanger operates at higher refrigerant pressure for efficient air heating, while the second heat exchanger operates at controlled, lower pressure to prevent excessive battery heating, thus resolving the contradiction between air heating efficiency and battery safety.
Solution Approach 2:
The refrigerant pressure parameter is changed and optimized for each heat exchanger separately. By controlling the refrigerant pressure in the second heat exchanger to be lower than in the first heat exchanger, the system achieves high air heating efficiency while maintaining battery temperature within safe limits, preventing degradation.
3Productivity
If the refrigeration cycle device heats the battery to high temperature to improve discharge efficiency, then the discharge efficiency is improved, but the battery may be degraded and become unusable
Solution Approach 1:
The refrigerant flow rate and pressure parameters are specifically optimized for the second heat exchanger to control battery temperature within the optimal range for discharge efficiency while preventing excessive heating that would cause degradation. This parameter optimization resolves the contradiction by achieving high discharge efficiency without compromising battery lifespan.
Solution Approach 2:
The system incorporates temperature sensing and control mechanisms that monitor battery temperature and adjust refrigerant flow accordingly, ensuring the battery is heated to the optimal temperature for discharge efficiency without exceeding safe limits, thus preventing degradation and maintaining reliability.
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 configuration enables precise temperature adjustment of batteries within a lower range than air, preventing degradation and maintaining optimal discharge efficiency, while also adjusting air temperatures for vehicle interior conditioning.
Implementation Method 1
a compressor (11) that compresses and discharges a refrigerant
Implementation Method 2
an air heat exchanger (12) that heats air to be blown into a space to be air conditioned using the refrigerant discharged from the compressor as a heat source
Implementation Method 3
a high-stage side decompressor (13a) that decompresses the refrigerant flowing out of the air heat exchanger
Implementation Method 4
a battery heat exchanger (15) that heats a battery using the refrigerant decompressed by the high-stage side decompressor as another heat source
Implementation Method 5
a low-stage side decompressor (13b) that decompresses the refrigerant flowing out of the battery heat exchanger
Implementation Method 6
an exterior heat exchanger (17) that exchanges heat between the refrigerant decompressed by the low-stage side decompressor and outside air to evaporate the refrigerant
Implementation Method 7
an accumulator (21) that separates the refrigerant flowing out of the exterior heat exchanger into gas-phase refrigerant and liquid-phase refrigerant
Data Source
AI summary
A refrigeration cycle device includes an air heat exchanger that heats air to be blown into an interior of a vehicle compartment using refrigerant discharged from a compressor, a high-stage side expansion valve decompressing the refrigerant flowing out of the air heat exchanger, and a battery heat exchanger that heats air to be blown to a battery using the refrigerant decompressed by the high-stage side expansion valve. In an air heating-warming up mode of heating the air for the interior and the air for the battery, a refrigerant discharge capacity of the compressor is controlled such that an air temperature for the interior approaches a target air temperature, and an opening degree of the high-stage side expansion valve is controlled such that a battery temperature becomes within a predetermined reference temperature range. A selector switch allows a passenger to select which operation of air conditioning or warming-up is prioritized.