Battery Cooling System with Dynamic Coolant Flow Control
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Solution Overview
Problem
Conventional battery cooling systems using evaporation heat of a coolant face temperature variations between cells due to vehicle acceleration, deceleration, and road inclinations, leading to inadequate cooling, especially in stacked battery configurations.
Innovation Solution
A cooling system with a controller that adjusts the flow volume of liquid-phase coolant based on detected forces and temperature variations, using multiple heat exchangers and sensors to maintain consistent cooling across battery cells and stacks, ensuring effective heat exchange and temperature regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a boundary between gas-phase and liquid-phase coolant is formed around the battery for evaporative cooling, then cooling efficiency is improved, but temperature variation between cells occurs due to vehicle acceleration, deceleration, and road inclinations
Solution Approach 1:
The patent applies dynamics by making the coolant supply system adaptive to vehicle motion states. The controller dynamically adjusts the opening degree of the control valve based on detected acceleration, deceleration, and road inclination, enabling the liquid-phase coolant supply to respond to changing gravitational and inertial forces that affect phase boundary stability.
Solution Approach 2:
The patent implements feedback control by using sensors to detect vehicle acceleration, deceleration, and road inclination, then feeding this information to the controller which adjusts the control valve opening degree accordingly. This closed-loop control compensates for disturbances that cause temperature variation between cells.
2Productivity
If liquid-phase coolant flow volume is increased to enhance cooling, then heat exchange efficiency is improved, but temperature variation between cells worsens under vehicle dynamics
Solution Approach 1:
The system dynamically adjusts coolant flow volume based on vehicle motion state. During acceleration or deceleration, the controller reduces the opening degree of the control valve to decrease liquid-phase coolant flow, preventing disruption of the phase boundary and maintaining temperature uniformity between cells.
Solution Approach 2:
The patent changes the flow volume parameter of liquid-phase coolant based on detected vehicle dynamics. By adjusting the control valve opening degree in response to acceleration, deceleration, and road inclination, the system optimizes coolant flow to maintain both heat exchange efficiency and temperature uniformity.
3Device complexity
If a common pipe for cells is used in the second heat exchanger, then device complexity is reduced, but temperature variation between cells increases due to force acting in stacking direction
Solution Approach 1:
The patent applies dynamics by making the coolant flow adjustable through a control valve in the common pipe. This allows the system to compensate for forces acting in the stacking direction during vehicle acceleration and deceleration, maintaining temperature uniformity despite using a simplified common pipe structure.
Solution Approach 2:
The controller uses feedback from acceleration and inclination sensors to adjust the control valve opening degree, compensating for gravitational and inertial forces that affect coolant distribution in the common pipe. This maintains temperature uniformity between cells while using a simple common pipe configuration.
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 effectively prevents temperature variations between cells by dynamically controlling coolant flow, ensuring consistent cooling and reducing the risk of cell degradation due to vehicle dynamics and road conditions.
Implementation Method 1
the battery is cooled by evaporation heat of a coolant. The evaporation heat is the heat that the coolant takes from the surroundings when the coolant of the fluid becomes gaseous
Implementation Method 2
The first heat exchanger is configured to change the coolant from the gas-phase to the liquid-phase
Implementation Method 3
The second heat exchanger is configured to exchange heat with the battery using liquid-phase coolant flowing from the first heat exchanger
Data Source
AI summary
It is determined whether or not the absolute value |a_sd| of the acceleration in the stacking direction of the cells is equal to or greater than the threshold THa (step S10). If the determination result of the step S10 is positive, it is determined whether or not the condition in which the absolute value |a_sd| is equal to or greater than the threshold THa continues (step S12). If the determination result of the step S12 is positive, the control valve is closed (step S14).