Battery Cooling Control for Low-Temperature Refrigerant Flow
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Solution Overview
Problem
High-voltage storage devices in electric vehicles face inadequate cooling at low ambient temperatures due to reduced refrigerant flow, leading to excessive temperature spread and potential overheating within battery cells.
Innovation Solution
A method to optimize cooling by detecting insufficient refrigerant flow through the evaporator and automatically reducing heat losses in the condenser, including rerouting refrigerant, adjusting ambient air flow, and adding heat to the condenser using waste heat or electrical heating, to maintain adequate cooling of high-voltage batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the refrigeration circuit operates at low ambient temperatures, then the system maintains basic cooling function, but the refrigerant mass flow becomes very small leading to insufficient cooling and excessive temperature spread in battery cells
Solution Approach 1:
The patent applies preliminary anti-action by pre-heating the condenser at low ambient temperatures before the cooling cycle begins. This preliminary heating creates a larger temperature difference between the refrigerant and ambient air, which prevents the refrigerant mass flow from becoming too small during subsequent cooling operations, thereby maintaining reliable cooling function.
Solution Approach 2:
The patent changes the temperature parameter of the condenser by actively heating it to a higher temperature than the ambient air. This parameter change creates a reversed temperature gradient that increases the temperature difference driving force for heat exchange, thereby maintaining adequate refrigerant mass flow and cooling reliability at low ambient temperatures.
2Loss of energy
If the condenser operates with a small temperature difference at low ambient temperatures, then heat loss is reduced, but the refrigerant mass flow decreases drastically leading to insufficient cooling capacity
Solution Approach 1:
The patent applies dynamics by making the condenser temperature adaptive rather than static. The condenser temperature is dynamically adjusted based on ambient temperature conditions - at low ambient temperatures, the condenser is heated to maintain an optimal temperature difference, while at higher temperatures, it operates normally. This dynamic adjustment ensures both energy efficiency and adequate cooling capacity across different operating conditions.
Solution Approach 2:
The patent changes the operational parameter of the condenser temperature to optimize system performance. By actively controlling the condenser temperature to be higher than ambient temperature at low ambient conditions, the system maintains a larger temperature difference that drives sufficient refrigerant mass flow, thereby preserving cooling capacity while managing heat loss through controlled thermal gradients.
3Temperature
If the cooling fluid is overheated to a high degree due to small mass flow, then the temperature difference between inlet and outlet increases, but this leads to division within battery cells with downstream cells overheating severely
Solution Approach 1:
The patent applies feedback by continuously monitoring the temperature distribution in the battery and adjusting the condenser temperature accordingly. When temperature spread between battery cells exceeds acceptable limits, the system responds by modifying the condenser heating, which in turn adjusts the refrigerant mass flow and cooling fluid temperature profile, creating a closed-loop control that maintains battery cell temperature uniformity.
Solution Approach 2:
The patent applies preliminary anti-action by pre-adjusting the condenser temperature to prevent excessive overheating of downstream battery cells. By proactively creating a larger temperature difference at the condenser level, the system ensures adequate refrigerant mass flow throughout the cooling circuit, which prevents the cooling fluid from being overheated to excessive degrees and thereby prevents severe temperature division in the battery cells before it occurs.
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
Ensures reliable operation of high-voltage storage devices at low temperatures by maintaining a suitable temperature difference across the condenser, preventing overheating and ensuring consistent performance across varying external temperatures.
Implementation Method 1
an evaporator (24) for cooling the high-voltage battery (1) by means of heat exchange
Implementation Method 2
a condenser element (3) for subsequent cooling of the refrigerant (R744) and an expansion element (10)
Implementation Method 3
a compressor (16) for compressing a refrigerant (R744)
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a control device and to a method for optimizing cooling of a high-voltage accumulator by means of an air-conditioning system in transport means. According to the invention, a coolant flow which is insufficient is detected by means of an evaporator for the high-voltage accumulator and as a result, heat losses inside a condenser of the air-conditioning system are reduced for increasing the flow of the coolant.