Electric Excavator Battery Control for Accurate Charge Time Estimation
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Solution Overview
Problem
Existing methods for estimating the remaining charge and discharge times of secondary batteries in electrically driven work machines fail to consider temperature changes, leading to decreased estimation accuracy and potential battery deterioration.
Innovation Solution
An electrically driven work machine equipped with a battery management unit that detects voltage, state of charge, and temperature, and a vehicle control unit that predicts temperature transitions to estimate remaining charge and discharge times based on these factors, adjusting current levels accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the current of the secondary battery is changed according to the change in temperature to suppress deterioration and reduce charge time, then battery performance is improved, but estimation accuracy of remaining charge time decreases when estimated only from present temperature
Solution Approach 1:
The system performs preliminary actions by detecting temperature at multiple time points during charging and predicting future temperature transitions before they occur. This allows the estimation to account for upcoming temperature changes rather than relying solely on current temperature, thereby maintaining accuracy even when current changes are implemented to optimize charging speed.
Solution Approach 2:
The system implements feedback by continuously monitoring temperature changes during charging and using this information to update the remaining charge time estimation. The temperature detection unit measures temperature at multiple time points, and the control unit uses this feedback to predict temperature transitions and adjust the estimation accordingly, ensuring accuracy despite dynamic current changes.
2Productivity
If the current of the secondary battery is increased to reduce charge time, then charging efficiency is improved, but battery deterioration accelerates
Solution Approach 1:
The system applies dynamics by making the charging current variable rather than constant. The control unit adjusts the charging current based on real-time temperature detection and predicted temperature transitions. This dynamic adjustment allows the system to increase current when temperature is low (improving charging efficiency) while decreasing current when temperature rises (protecting battery durability).
Solution Approach 2:
The system changes the parameter of charging current based on temperature conditions. By detecting temperature at multiple time points and predicting temperature transitions, the control unit modifies the current parameter adaptively - increasing it to improve charging efficiency when safe, and decreasing it to protect battery durability when temperature becomes concerning.
3Device complexity
If the remaining charge time is estimated based on present temperature only, then estimation process is simplified, but estimation accuracy decreases when temperature changes during charging
Solution Approach 1:
The system performs preliminary temperature detection at multiple time points during charging and predicts future temperature transitions. This preliminary action provides the basis for accurate estimation without requiring complex real-time adjustments, as the temperature trajectory is already captured and analyzed in advance.
Solution Approach 2:
The system uses feedback from continuous temperature monitoring to improve estimation accuracy. By detecting temperature at multiple time points and using this feedback to predict temperature transitions, the system maintains accurate remaining charge time estimation without overly complicating the process, as the feedback mechanism systematically incorporates temperature changes.
Data Source
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AI summary
Provided is an electrically driven work machine capable of increasing estimation accuracy of a remaining charge time or a remaining discharge time of a secondary battery. An electrically driven excavator includes a secondary battery, a battery management unit, and a vehicle control unit. The vehicle control unit predicts a transition of a temperature of the secondary battery on the basis of the temperature and a state of charge of the secondary battery detected by the battery management unit, predicts a transition of a current of the secondary battery on the basis of the predicted transition of the temperature of the secondary battery, and estimates the remaining charge time or the remaining discharge time of the secondary battery on the basis of the predicted transition of the current of the secondary battery.