Battery Voltage Control via Current and Resistance Prediction
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Solution Overview
Problem
Conventional battery control systems for hybrid electric vehicles only consider internal resistance, neglecting charging-discharging current and state of charge, leading to inefficient use of the battery's wide performance range.
Innovation Solution
An apparatus with an estimation circuit for internal resistance, a detection circuit for charging-discharging current, and a control circuit that predicts battery voltage behavior to limit current or power, ensuring the battery voltage remains within a predetermined range, thereby utilizing the battery's inherent performance efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery charging-discharging is controlled based on only the internal resistance of the battery, then the battery voltage can be limited within a control range, but the charging-discharging performance of the battery cannot be used efficiently
Solution Approach 1:
The patent changes the control parameters from solely internal resistance to a comprehensive set including internal resistance, charging-discharging current, and state of charge. This allows the control system to accurately predict battery voltage behavior and determine the appropriate control range, thereby resolving the contradiction between voltage control reliability and performance utilization.
Solution Approach 2:
The patent implements a feedback mechanism where the control unit continuously monitors internal resistance, charging-discharging current, and state of charge, predicts battery voltage behavior, and adjusts the control range accordingly. This closed-loop control ensures both voltage stability and efficient performance utilization.
2Device complexity
If the battery control range is determined based on estimated internal resistance only, then the control system is simple, but the battery's wide performance range is not fully utilized
Solution Approach 1:
The patent expands the control parameters from a single parameter (internal resistance) to multiple parameters (internal resistance, charging-discharging current, state of charge). This allows the system to utilize the battery's full performance range while maintaining manageable complexity through systematic prediction and control.
Solution Approach 2:
The patent performs preliminary prediction of battery voltage behavior based on current and state of charge before actual charging-discharging operations. This advance planning allows the control system to set appropriate control ranges that maximize performance utilization without excessive complexity during operation.
3Reliability
If the charging-discharging control is based on narrow range determined by internal resistance only, then overcharging and overdischarging are prevented, but the battery performance is not efficiently used
Solution Approach 1:
The patent changes the control approach from narrow range based on internal resistance to a wider, dynamically adjusted range based on internal resistance, charging-discharging current, and state of charge. This maintains protection against overcharge and overdischarge while efficiently utilizing battery performance.
Solution Approach 2:
The patent implements dynamic control where the control range is not fixed but adjusts based on real-time battery conditions including current and state of charge. This dynamic adaptation allows the system to maintain safety while maximizing performance utilization across different operating conditions.
Data Source
AI summary
A battery charging-discharging control apparatus includes an estimation circuit, a detection circuit, and a control circuit. The estimation circuit estimates an internal resistance of a battery. The detection circuit detects a charging-discharging current of the battery. The control circuit predicts a behavior of a voltage of the battery based on behaviors of the internal resistance and the charging-discharging current of the battery. The control circuit limits the charging-discharging current or a charging-discharging power of the battery based on the predicted behavior of the battery voltage in such a manner that the battery voltage is within a predetermined voltage range.