Battery State Estimation Using Voltage Change Timing Ratios

Solution Overview

Problem

Conventional methods for estimating stable open circuit voltage in storage batteries require complex computations involving multiple exponential functions, leading to a heavy computing load and complicated parameter setting.

Innovation Solution

A battery state estimation device that sets reference and subsequent timings based on battery voltage changes to estimate open circuit voltage using simple computations, leveraging time differences to accurately predict the stable open circuit voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional methods using multiple exponential functions are used to estimate stable open circuit voltage, then measurement precision is improved, but device complexity and computing load increase

Engineering Contradiction:

Improveopen circuit voltage estimation accuracyVSAvoidcomputation complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential timing information (three specific time points during voltage transient response) needed for open circuit voltage estimation, discarding the complex multi-exponential function fitting approach. This extraction of key temporal characteristics simplifies the computational model while preserving estimation accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using complex mathematical functions to model voltage decay and then inverting the relationship to find open circuit voltage, the patent inverts the approach by directly using measured voltage values at specific time points to calculate open circuit voltage through a simplified formula, reversing the traditional modeling-inversion paradigm.

Inventive Principle:

Principle #13The other way round (Inversion)

2Measurement precision

If conventional methods using multiple exponential functions are used to estimate stable open circuit voltage, then measurement precision is improved, but computing load increases

Engineering Contradiction:

Improveopen circuit voltage estimation accuracyVSAvoidcomputing energy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential timing information (three specific time points during voltage transient response) needed for open circuit voltage estimation, discarding the complex multi-exponential function fitting approach. This extraction of key temporal characteristics simplifies the computational model while preserving estimation accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive, computationally intensive mathematical modeling with a simple, lightweight calculation method that uses minimal processing resources. The simplified formula requires negligible computing energy compared to conventional methods, making it suitable for embedded battery management systems.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If conventional methods using multiple exponential functions are used to estimate stable open circuit voltage, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:

Improveopen circuit voltage estimation accuracyVSAvoidparameter setting simplicity

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent extracts only the essential timing information (three specific time points during voltage transient response) needed for open circuit voltage estimation, discarding the complex multi-exponential function fitting approach. This extraction of key temporal characteristics simplifies the computational model while preserving estimation accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent enables the system to automatically determine the three critical time points by monitoring when voltage changes reach specific thresholds (10%, 50%, 90% of total voltage change), eliminating the need for manual parameter setting or complex calibration procedures. The method is self-adapting to different battery conditions.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS9846200B2Battery state estimation device and storage battery system

Publication Date: 2017.12.19 PANASONIC ENERGY CO LTD

AI summary

After charging or discharging is stopped, a reference timing (t0) is set, and a first timing (t1) at which battery voltage (V) changes by a unit amount (N) with respect to the reference timing (t0), and a second timing (t2) at which the battery voltage changes by twice more than the unit amount with respect to the reference timing (t0) are select and set. The ratio of the time difference (t2−t1) between the first and the second timing to the time difference (t1−t0) between the reference and the first timing is found as a voltage change parameter (R) corresponding to the rate of change of the change speed of the voltage battery. An estimation device considers the change rate determined by the parameter is considered to be unchanged during an electrical current non-passage, and estimates a stable open circuit voltage at an object timing in future after the second timing.