Battery Pack Management Voltage Compensation
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Solution Overview
Problem
Existing battery pack management systems face inaccuracies in estimating remaining capacity due to factors like self-discharge rate and coulombic efficiency, which are not effectively accounted for in simplistic monitoring methods.
Innovation Solution
A method and apparatus that determine the remaining time to empty of a battery by measuring and compensating for changes in voltage associated with battery conditions such as temperature and current, using a processor to adjust discharge calculations based on stored data and current draw, and updating tables to reflect changes in battery performance over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If current drawn from the battery is monitored over a period of time to estimate remaining capacity, then the monitoring method is simple, but the accuracy of remaining capacity estimation deteriorates due to factors like self-discharge rate and coulombic efficiency
Solution Approach 1:
The patent introduces voltage change as an intermediary parameter to indirectly measure battery capacity. Instead of directly monitoring current over time (which has accuracy issues), the system measures voltage changes at different states of charge and uses these as a mediator to calculate remaining capacity, thereby improving accuracy while maintaining operational simplicity
Solution Approach 2:
The patent changes the measurement parameter from current monitoring to voltage monitoring. By measuring voltage changes (dV) rather than integrating current over time, the system accounts for self-discharge rate and coulombic efficiency effects, achieving more accurate remaining capacity estimation without complex monitoring procedures
2Measurement precision
If detailed information of battery chemical make-up and special hardware is incorporated to accurately estimate remaining capacity, then the accuracy of remaining capacity estimation improves, but the device complexity increases
Solution Approach 1:
The patent enables the battery management system to self-calibrate by measuring voltage changes during normal operation and automatically updating lookup tables. The system uses its own operational data (voltage, current, temperature measurements) to improve its accuracy over time without requiring external calibration equipment or complex chemical analysis hardware
Solution Approach 2:
The patent pre-calculates and stores voltage change characteristics in lookup tables during battery manufacturing or initial operation. These pre-computed tables contain voltage change data for different states of charge, temperatures, and current rates, allowing the system to quickly estimate remaining capacity during operation without performing complex real-time calculations or requiring detailed chemical composition knowledge
Data Source
AI summary
An electronic device includes a processor coupled to a battery and to determine whether the battery is being charged or discharged. If the battery being is being discharged, the processor operates to calculate an amount by which the battery has discharged since a preceding calculation of remaining capacity of the battery, compensate the amount by which the battery has discharged for a condition of the battery, and calculate a remaining capacity of the battery as a function of the amount by which the battery has discharged. If the battery is being charged, the processor operates to calculate an amount by which the battery has charged since a preceding calculation of remaining capacity of the battery, compensate the amount by which the battery has charged for a condition of the battery, and calculate the remaining capacity of the battery as a function of the amount by which the battery has charged.