Battery OCV Estimation During Rest Periods

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Solution Overview

Problem

Existing battery management systems fail to accurately estimate battery parameters during rest periods, leading to errors in voltage profiling and potential safety issues due to the neglect of exponential voltage decay and physical aspects of battery diffusion equilibration, which can result in incorrect state of health and short circuit detection.

Innovation Solution

A method and system that calculate the open circuit voltage (OCV) of a battery based on initial voltage, time constants for positive and negative electrodes, and constants derived from state of charge and maximum intercalation metal concentration, allowing for accurate estimation of battery parameters like state of health and short circuit status during rest periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing battery management systems use conventional voltage profiling methods, then the system complexity is low, but the measurement precision of battery parameters during rest periods deteriorates due to neglect of exponential voltage decay and diffusion equilibration

Engineering Contradiction:

Improvebattery parameter estimation accuracyVSAvoidvoltage profiling model complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the mathematical parameters of the voltage profiling model by introducing exponential decay terms with time constants specific to positive and negative electrodes. This transforms the conventional linear voltage profile into an exponential model that accurately captures the physical behavior of battery voltage during rest periods, thereby improving measurement precision without excessive complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces simple algebraic voltage calculations with a differential equation-based model that incorporates exponential functions. This substitution allows the system to capture the dynamic physical processes of voltage decay and diffusion equilibration, achieving higher accuracy in battery parameter estimation during rest periods

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If battery management systems neglect exponential voltage decay, then the calculation complexity is reduced, but the reliability of short circuit detection deteriorates

Engineering Contradiction:

Improveshort circuit detection accuracyVSAvoidvoltage profiling calculation complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements feedback by continuously monitoring voltage during rest periods and comparing it against the exponential decay model predictions. When the actual voltage deviates from the modeled behavior, the system can detect anomalies such as short circuits, thereby improving reliability through model-based validation

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent performs preliminary voltage profiling during rest periods before actual fault detection is needed. By establishing the expected exponential decay trajectory in advance, the system creates a baseline for detecting deviations that indicate short circuits, improving detection reliability through proactive characterization

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If battery management systems ignore diffusion equilibration physical aspects, then the ease of operation is maintained, but the measurement precision of electrochemical parameters deteriorates

Engineering Contradiction:

Improveelectrochemical parameter estimation accuracyVSAvoidbattery management operation simplicity

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent changes the operational parameters by introducing electrode-specific time constants and exponential decay rates into the voltage profiling model. These parameter changes enable the system to capture diffusion equilibration physics while maintaining a relatively simple operational interface, balancing precision with ease of use

Inventive Principle:

Principle #35Parameter changes

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

This approach provides more accurate voltage profiling and estimation of electrochemical parameters, enabling early detection of short circuits and improving battery health assessment, reducing errors and safety risks in electric vehicles and wireless devices.

Implementation Method 1

the neglect of exponential voltage decay and physical aspects of battery diffusion equilibration

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS20230400525A1Method and system with battery parameter estimation for rest period

Publication Date: 2023.12.14 SAMSUNG ELECTRONICS CO LTD

AI summary

The following description relates to a method and system with battery parameter estimation for a rest period. A method of estimating a battery parameter of a battery for a rest period of the battery includes: based on determining that an intercalation flux of the battery satisfies a predetermined condition, calculating an open circuit voltage (OCV) of the battery, wherein the OCV is calculated based on an initial voltage, a first time constant corresponding to a positive electrode of the battery, a second time constant corresponding to a negative electrode of the battery, a first constant, a second constant, and a value of a time variable for the rest period; and estimating the battery parameter based on the calculated OCV of the battery.