Power Storage Module State Estimation with Hysteresis Compensation
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Solution Overview
Problem
Existing power storage member state estimation technologies face challenges in precisely estimating open circuit voltage (OCV) due to hysteresis effects caused by charge and discharge history, leading to inaccuracies in state of charge (SOC) and state of health (SOH) calculations.
Innovation Solution
A power storage member state estimation device that performs hysteresis compensation on OCV calculations using parameters such as current direction, average current, and temperature, allowing for precise estimation of OCV and subsequent SOC and SOH by referencing adjusted OCV curves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional OCV estimation methods are used, then the estimation process is simple, but the measurement precision of OCV is poor due to hysteresis effects
Solution Approach 1:
The patent changes the parameters used for OCV estimation from simple voltage measurements to a comprehensive set including charge-discharge current, temperature, and time. By incorporating these additional parameters and their historical variations, the system compensates for hysteresis effects and achieves precise OCV estimation without requiring complex hardware modifications
Solution Approach 2:
The patent introduces an OCV estimation unit that acts as an intermediary between the power storage member and the control system. This unit processes multiple input parameters (current, temperature, time) through calculation algorithms to produce an accurate OCV estimate, mediating the complex relationship between charge-discharge history and voltage output
2Measurement precision
If charge and discharge history is considered in OCV estimation, then the measurement precision improves, but the calculation complexity increases
Solution Approach 1:
The patent performs preliminary actions by continuously monitoring and storing charge-discharge current, temperature, and time parameters before OCV estimation is needed. The OCV estimation unit has ready access to this pre-collected historical data, eliminating the need for complex real-time tracking during the estimation process itself
Solution Approach 2:
The patent implements feedback mechanisms where the OCV estimation result is fed back to verify consistency with measured terminal voltage. The system continuously adjusts its understanding of charge-discharge history based on the difference between estimated and measured values, improving estimation accuracy over time without increasing fundamental calculation complexity
3Reliability
If hysteresis compensation is performed using multiple parameters, then the SOC and SOH calculation accuracy improves, but the device complexity increases
Solution Approach 1:
The patent makes the OCV estimation unit multi-functional by designing it to handle multiple tasks: estimating OCV, calculating SOC, determining SOH, and providing feedback for control decisions. By consolidating these functions into a single processing unit that accepts multiple parameters, the system achieves high reliability without proportionally increasing device complexity
Solution Approach 2:
The patent merges the measurement and processing of charge-discharge current, temperature, time, and terminal voltage into a unified estimation framework. The OCV estimation unit combines these previously separate measurement streams into a single coherent estimation process, reducing overall system complexity while improving reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device achieves high precision in OCV estimation, reducing errors in SOC and SOH calculations, even during transition processes between charging and discharging states, thereby improving the accuracy of power storage member state assessments.
Implementation Method 1
hysteresis effects caused by charge and discharge history
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
According to an example embodiment of the present disclosure, a power storage module state estimation apparatus comprises a parameter calculator configured to calculate a parameter based on a current value of a power storage module, wherein the parameter includes at least one of a direction having a high frequency of current flowing in the power storage module, an average current value of the power storage module, and a charge and discharge capacity after the direction having the high frequency of current flowing in the power storage module is switched; and a hysteresis compensator configured to use the parameter to compensate an open circuit voltage of the power storage module.