Multi-Battery Power Limiting Control in Electric Working Machines
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Solution Overview
Problem
Existing electric working machines fail to efficiently utilize the remaining charge of multiple battery packs when the charge level of one battery pack falls below a threshold, leading to incomplete utilization of available battery capacity.
Innovation Solution
Implement a controller that selectively designates a discharging battery pack based on the charge levels of all battery packs, adjusting the limiting process to conserve energy by reducing power consumption in devices when certain battery packs are low, and allowing higher power usage when other packs have sufficient charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output battery is switched when the remaining charge level falls below the first threshold, then the battery level notification function is improved, but the utilization efficiency of remaining battery charge deteriorates
Solution Approach 1:
The controller dynamically adjusts the threshold for switching between battery packs based on the remaining charge levels of all battery packs. Instead of using a fixed first threshold, the system selects a second threshold from multiple candidates (first, second, third thresholds) depending on the charge states of other battery packs, thereby optimizing the utilization of remaining charge while maintaining reliable battery level notification.
Solution Approach 2:
The battery management system transitions from a static threshold-based switching mechanism to a dynamic decision-making process that continuously monitors the charge levels of all battery packs and adjusts the switching threshold in real-time. This allows the system to adapt to varying battery states and maximize energy utilization efficiency.
2Device complexity
If a fixed threshold is used for battery switching, then the control logic is simplified, but the efficiency of using remaining battery charge deteriorates
Solution Approach 1:
The system employs multiple threshold values (first, second, third thresholds) and dynamically selects which threshold to apply based on the charge levels of battery packs. This parameter-based approach maintains relatively simple control logic while significantly improving the efficiency of utilizing remaining battery charge compared to a single fixed threshold.
3Reliability
If the remaining charge level of all batteries is below the first threshold before switching, then the battery notification function operates correctly, but full utilization of remaining charge becomes impossible
Solution Approach 1:
The controller proactively monitors the charge levels of all battery packs and performs preliminary assessment before triggering a battery switch. By evaluating whether other battery packs have sufficient charge (above the second threshold), the system prevents premature switching that would waste remaining charge, while still ensuring the battery notification function operates reliably.
Data Source
AI summary
An electric working machine includes battery packs, an actuated device to be actuated by electricity supplied from the battery packs, and a controller to control discharging of the battery packs based on remaining charge levels of the battery packs. The controller is configured/programmed to select one of the battery packs as a discharging battery pack, and perform a limiting process to limit electricity supplied from the discharging battery pack to the actuated device when the remaining charge level of the discharging battery pack is less than a limit threshold, and cause the limit threshold and/or content of the limiting process to differ between when one or more of the battery packs that are other than the discharging battery pack have a remaining charge level of a second threshold or more and when any of such battery packs do not have a remaining charge level of the second threshold or more.