Battery State Vector Estimation After Decoupling

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Solution Overview

Problem

Existing battery monitoring systems cannot accurately determine the state of a battery when it is electrically coupled to a load circuit after being decoupled, leading to inaccuracies in state-of-charge estimation.

Innovation Solution

A method and system that calculate a predicted state vector based on a previously determined state vector and time interval of decoupling, measuring battery voltage after recoupling, and adjusting with a voltage error value to estimate the current state vector, using sensors and computational units to refine the estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the battery monitoring system interrupts measurements and calculations during the discharge time interval, then the system can simplify operations during unloading, but it cannot accurately determine the battery state after recoupling to the load circuit

Engineering Contradiction:
Improvesystem operation simplicityVSAvoidbattery state determination accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system performs preliminary calculations of the predicted state vector during the discharge time interval when the battery is electrically decoupled from the load circuit. This preliminary action allows the system to maintain accuracy without continuous measurement interruptions, as the predicted state vector is ready before recoupling occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback by comparing the measured battery voltage after recoupling with the predicted battery voltage to calculate a voltage error value. This error feedback is then used to adjust the state vector estimation, ensuring continuous accuracy throughout the discharge and recoupling cycles.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If the system continuously measures and calculates battery state during discharge, then accuracy is maintained, but computational resources and measurement frequency increase

Engineering Contradiction:
Improvebattery state determination accuracyVSAvoidmeasurement and calculation frequency
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary calculations of the predicted state vector during the discharge time interval when the battery is electrically decoupled from the load circuit. This preliminary action allows the system to maintain accuracy without continuous measurement interruptions, as the predicted state vector is ready before recoupling occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system maintains continuous state estimation capability by combining preliminary predicted state vector calculations with post-recoupling measurements and corrections. This ensures the state vector remains accurately updated throughout the entire discharge-recoupling cycle without requiring continuous active measurement.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP1917536B1System and method for estimating a state vector associated with a battery
Publication Date: 2018.08.08 LG CHEM LTD
  • EP1917536B1 patent drawingFigure 1
  • EP1917536B1 patent drawingFigure 2
  • EP1917536B1 patent drawingFigure 3

AI summary

A system and a method for estimating a state vector associated with a battery are provided. The method includes determining a time interval that the battery has been electrically decoupled from a load circuit. The time interval starts at a first time. The method further includes obtaining a first state vector associated with the battery from a memory. The first state vector is determined prior to the first time. The method further includes calculating a second predicted state vector associated with the battery based on the first state vector and the time interval.