Vehicle Battery Cooling Fan Control for Problem Detection
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Solution Overview
Problem
Conventional cooling systems for hybrid vehicle secondary batteries face challenges in accurately detecting fan issues without causing discomfort to passengers, as constant fan duty leads to insufficient cooling or overcooling, and variable duty control is ineffective in maintaining optimal battery temperature.
Innovation Solution
A cooling system that performs constant control of the cooling fan at specific temperature thresholds and noise levels to detect fan problems while preventing overheating or overcooling, using a first and second command value for fan operation based on battery temperature and noise conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cooling fan is driven at a constant duty to stabilize driving for problem detection, then the reliability of problem detection is improved, but the battery temperature control deteriorates (insufficient cooling or overcooling)
Solution Approach 1:
The system performs periodic constant duty control at specific intervals (e.g., every 10 seconds) to create opportunities for problem detection, while using variable duty control at other times to maintain optimal battery temperature. This periodic approach allows the system to stabilize fan driving temporarily for accurate problem detection without continuously compromising temperature control.
Solution Approach 2:
The system dynamically switches between constant duty control mode (for problem detection) and variable duty control mode (for temperature management). The control unit adjusts the duty cycle based on real-time conditions, including battery temperature, vehicle speed, and noise level, thereby resolving the contradiction between detection reliability and temperature control.
2Temperature
If the cooling fan is controlled at high output state to ensure sufficient cooling, then the battery cooling is improved, but passenger comfort deteriorates due to increased noise
Solution Approach 1:
The system changes the duty cycle parameter dynamically based on operating conditions. When problem detection is needed and noise levels are acceptable, the fan operates at higher duty cycles. When passengers are present and noise sensitivity is high, the system reduces duty cycle to lower noise levels, thereby balancing cooling effectiveness with passenger comfort.
3Temperature
If variable control is used to maintain optimal battery temperature, then the battery temperature control is improved, but the accuracy of problem detection deteriorates due to control delay
Solution Approach 1:
The system performs preliminary constant duty control before problem detection to stabilize the fan's driving state. By establishing a stable baseline operation first, the system ensures that subsequent problem detection measurements are accurate and not influenced by transient control delays or varying operating conditions.
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 detection of cooling fan issues while maintaining passenger comfort and preventing battery overheating or overcooling, enhancing the cooling system's effectiveness and accuracy.
Implementation Method 1
a cooling fan configured to blow cooled air to the secondary battery
Data Source
AI summary
If the battery temperature TB of the main battery is equal to or higher than the first temperature T0 and a noise level within a vehicle interior is equal to or higher than a predetermined value Lo during inhibition of the first constant control under a predetermined condition, the cooling system performs second constant control for driving the cooling fan with a second command value D3 and also performs the problem detection processing based on an actual rotation rate of the cooling fan during the second constant control.