Accumulator SOC Estimation Using Deterioration Models
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Solution Overview
Problem
Existing methods for precisely estimating the state of charge (SOC) of lead accumulators fail to account for deterioration over time, which affects the operational conditions and lifetime of the batteries, leading to increased costs and reduced efficiency in wind power electricity generation systems.
Innovation Solution
A system that includes multi-dimensional characteristic models relating terminal voltage, current, and SOC for various deterioration degrees, along with units for measuring and estimating deterioration, selecting appropriate models, and combining estimates from different measurement types to determine the accurate SOC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional SOC estimation methods using pre-established relational models are used, then the estimation process is simple, but the accuracy deteriorates as the accumulator deteriorates over time
Solution Approach 1:
The patent applies dynamics by transitioning from static pre-established relational models to dynamic models that adapt to the accumulator's deterioration state. The system continuously updates the relational expression between terminal voltage, current, and SOC based on the actual deterioration degree, allowing the estimation model to evolve with the accumulator's aging process and maintain accuracy throughout its lifetime.
Solution Approach 2:
The patent changes parameters by introducing deterioration degree as an additional parameter that modifies the traditional voltage-current-SOC relationship. By incorporating deterioration degree into the relational expression, the system adjusts the parameters of the estimation model to reflect the accumulator's current state, thereby maintaining estimation accuracy despite parameter changes due to aging.
2Duration of action of stationary object
If the accumulator is used longer to reduce replacement costs, then the system cost decreases, but the SOC estimation accuracy deteriorates due to deterioration
Solution Approach 1:
The patent implements feedback by continuously monitoring the accumulator's deterioration degree and using this information to update the SOC estimation model. The system feeds back the actual state of the accumulator into the estimation process, allowing the model to compensate for deterioration effects and maintain accurate SOC estimation throughout the accumulator's extended operational life.
Solution Approach 2:
The patent applies preliminary action by establishing a framework that anticipates deterioration effects before they significantly impact performance. By proactively incorporating deterioration degree measurements and adjusting the model in advance, the system prevents accuracy degradation rather than reacting to it after the fact.
3Measurement precision
If multiple measurement methods are combined to improve SOC estimation accuracy, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent merges multiple measurement approaches (terminal voltage measurement, current measurement, and deterioration degree estimation) into a unified SOC estimation system. By combining these measurements within a single relational framework that accounts for deterioration, the system achieves high accuracy without creating separate independent systems, thus controlling complexity while improving precision.
Data Source
AI summary
An accumulator and state of charge evaluation method for preparing, during charging and discharging, models for each of deterioration degrees, each representing a relationship between terminal voltage, current and state of charge, for selecting respective models for the times during charging and discharging in accordance with a total charging/discharging amount (Ah), a deterioration degree or an elapsed time of an operation of the accumulator, for further estimating state of charge from current accumulation, and for determining a final state of charge from estimated states of charge including a present state of charge estimated from the models for the times during charging and discharging of the accumulator, while using a time or a total charging/discharging amount (Ah) from a time of full-charging by equal charging of the accumulator up to present time to determine the final state of charge from the plurality of states of charge.