Accumulator Cooling Control Under Low Refrigerant Flow
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Solution Overview
Problem
High-voltage batteries in electric vehicles face inadequate cooling during low ambient temperatures, leading to excessive temperature spread and overheating due to reduced refrigerant flow, which can result in critical states and reduced battery performance.
Innovation Solution
A method to optimize cooling by identifying excessively low refrigerant flow through the evaporator and automatically reducing heat losses in the condenser, including bypassing part of the condenser, reducing ambient air flow, and adding heat to the condenser using waste heat or electrical heating, to increase the refrigerant flow and maintain temperature differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the refrigerant flow is reduced at low ambient temperatures, then the temperature difference in the condenser increases, but the refrigerant flow through the evaporator becomes excessively low
Solution Approach 1:
The condenser is divided into two separate circuits: a first condenser circuit and a second condenser circuit. The refrigerant flow can be selectively directed through either circuit using a switching mechanism. This segmentation allows the system to optimize the temperature difference in the condenser while maintaining adequate refrigerant flow through the evaporator by choosing the appropriate circuit based on operating conditions.
Solution Approach 2:
The system dynamically switches between the first and second condenser circuits based on ambient temperature conditions and cooling demands. A control device monitors the operating parameters and automatically selects the optimal circuit configuration, enabling the system to adapt to varying thermal conditions while maintaining proper refrigerant flow distribution.
2Loss of energy
If the refrigerant flow through the evaporator is excessively low, then the heat dissipation decreases, but the temperature spread within the accumulator cells increases
Solution Approach 1:
By segmenting the condenser into two independent circuits with selectable configurations, the system can maintain optimal refrigerant flow through the evaporator while managing heat dissipation effectively. The switching mechanism ensures that sufficient refrigerant reaches the evaporator to prevent excessive temperature spread in the battery cells, even when ambient temperatures vary.
Solution Approach 2:
The control device continuously monitors the refrigerant flow conditions and temperature parameters, and automatically switches between condenser circuits to maintain optimal operating conditions. This feedback mechanism ensures that the refrigerant flow through the evaporator remains sufficient to prevent excessive temperature spread while adapting to changing thermal loads.
3Reliability
If additional hardware is added to optimize refrigerant flow, then the cooling performance improves, but the device complexity increases
Solution Approach 1:
The switching mechanism serves multiple functions: it directs refrigerant flow through different condenser circuits, optimizes temperature difference management, and maintains proper refrigerant flow distribution. This multi-functional approach improves cooling performance without requiring separate dedicated components for each function, thereby limiting the increase in device complexity.
Solution Approach 2:
The system optimizes cooling performance by changing the operational parameters of existing components rather than adding substantial new hardware. The switching between condenser circuits modifies the thermal and flow parameters dynamically, achieving reliable cooling adaptation while keeping the overall system complexity manageable through parameter optimization rather than structural expansion.
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 batteries by maintaining adequate cooling and reducing temperature spread, even in extreme temperatures, through efficient heat management and refrigerant flow optimization without additional hardware.
Implementation Method 1
an evaporator (24) for cooling the high-voltage accumulator
Implementation Method 2
refrigerant flow through the evaporator
Implementation Method 3
heat losses within a condenser (3) of the air-conditioning system
Implementation Method 4
dissipation of heat
Data Source
AI summary
A control device, and a method for operating the control device, optimizes cooling of a high-voltage accumulator using an air-conditioning system in a vehicle. A coolant flow which is insufficient is detected by 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.