Energy Storage SOC Tail-End Calibration Using Voltage Feedback
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Solution Overview
Problem
The existing methods for estimating State of Charge (SOC) in energy storage systems are prone to errors, leading to significant discrepancies between estimated and actual SOC values, especially at the tail end of charging or discharging, causing inaccurate SOC displays and user experience issues.
Innovation Solution
A method and device for calibrating SOC by acquiring battery parameters during charging or discharging, determining pre-calibrated calibration SOC and voltage, and adjusting the SOC based on specific conditions to ensure accuracy, avoiding sudden SOC jumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the SOC is directly calibrated to 100% when the energy storage system is fully charged or to 0% when fully discharged, then the SOC estimation method is simple, but the SOC accuracy deteriorates due to large errors between estimated and actual SOC values
Solution Approach 1:
The patent applies preliminary action by pre-calibrating calibration SOC and calibration voltage values at the tail end of charging and discharging cycles before actual use. These pre-determined values are stored and used for comparison during operation, allowing the system to proactively identify and correct SOC estimation errors before they cause significant inaccuracies, thus improving SOC accuracy without adding complex real-time calculation mechanisms.
2Duration of action of stationary object
If the SOC estimation error becomes increasingly large during long-term operation, then the battery management system operates continuously, but the SOC accuracy deteriorates at the tail end of charging or discharging
Solution Approach 1:
The patent implements feedback by continuously comparing the actual battery voltage with the pre-calibrated calibration voltage during charging and discharging operations. When the voltage difference exceeds a predetermined threshold, the system triggers SOC calibration using the pre-stored calibration values. This feedback mechanism ensures that SOC accuracy is maintained throughout long-term operation, particularly at the tail end of charging or discharging cycles where errors would otherwise accumulate.
3Ease of manufacture
If the SOC displayed by the meter directly jumps to 100% or 0% when the error between estimated and actual SOC is large, then the calibration process is simple, but the user experience deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calibrating and storing calibration SOC and calibration voltage values for both charging and discharging states before actual operation. This preparation allows the system to perform smooth, incremental SOC adjustments rather than abrupt jumps to 100% or 0%, significantly improving user experience while maintaining calibration simplicity through the use of pre-computed reference values.
Data Source
AI summary
A method and a device for calibrating an SOC at tail end of charging or discharging of an energy storage system are provided. An SOC and a voltage of a battery unit are acquired in real time during charging or discharging of the battery unit. Whether the battery unit meets an SOC calibration condition is determined by comparing the SOC of the battery unit with a pre-calibrated calibration SOC at the tail end of charging/discharge and comparing the voltage of the battery unit with a calibration voltage, so that the SOC of the battery unit is timely calibrated if the SOC calibration condition is met.