Battery Discharge Current Control for Temperature Management
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Solution Overview
Problem
Existing hybrid vehicle control systems for lithium-ion batteries face challenges in balancing battery discharge current to prevent deterioration while maintaining efficient power supply to the electric motor, as sudden changes in discharge current values can lead to inefficient heat management and reduced driving torque or power supply.
Innovation Solution
A control system that determines upper and charge limit current values based on battery temperature, maintaining constant or gradually adjusting these values across specific temperature ranges to minimize battery deterioration and ensure high current supply to the electric motor, with predetermined temperature thresholds to manage heat generation and discharge/charge processes effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the upper limit discharge current value is immediately increased as battery temperature falls, then the battery can supply higher current, but heat generation increases and battery temperature falls less easily, causing deterioration
Solution Approach 1:
The patent applies dynamics by making the upper limit discharge current value changeable based on battery temperature conditions. The control unit dynamically adjusts the current limit according to temperature ranges, transitioning from a fixed value to a variable value that adapts to thermal conditions, thereby optimizing power output while managing heat generation.
Solution Approach 2:
The patent changes the parameter of discharge current limit based on temperature. By dividing temperature into ranges and setting different current limits for each range, the system modifies the electrical parameter (current) in response to thermal parameter changes, resolving the contradiction between power output and temperature control.
2Reliability
If the upper limit discharge current value is immediately decreased as battery temperature rises, then battery deterioration is prevented, but power supplied to electric motor drops, reducing driving torque
Solution Approach 1:
The system dynamically adjusts the discharge current limit based on real-time temperature monitoring. By making the current limit a variable parameter that responds to temperature changes, the system balances reliability (preventing deterioration) with performance (maintaining power output) across different operating conditions.
Solution Approach 2:
The patent modifies the electrical parameter (discharge current limit) in response to thermal parameter changes. By establishing temperature-dependent current limits, the system achieves parameter coordination that prevents battery deterioration while minimizing impact on motor power supply.
3Device complexity
If a fixed upper limit discharge current value is used, then control is simple, but battery deterioration occurs at high temperatures and insufficient power is supplied at low temperatures
Solution Approach 1:
The patent segments the temperature range into multiple intervals, with each segment having its own optimized discharge current limit. This segmentation allows the system to address different thermal conditions separately, improving battery performance across the full temperature range while maintaining manageable control complexity through structured temperature-based classification.
Data Source
AI summary
A utility vehicle includes an electric motor for driving a propelling device, a battery for supplying electric power to the electric motor, a temperature sensor configured to detect a temperature of the battery, a discharge current setting unit for setting an upper limit discharge current value based on the detected temperature detected by the temperature sensor, and a control unit for regulating discharge current of the battery within the upper limit discharge current value determined by the discharge current setting unit and for controlling driving of the electric motor.