SOC-OCV Profile Estimation Using Half-Cell Data

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Solution Overview

Problem

Existing methods for updating the state of charge-open circuit voltage (SOC-OCV) profile of secondary batteries are time-consuming and inefficient, as they require repeated measurements and long experiments to reflect degradation rates.

Innovation Solution

An apparatus and method that estimate the SOC-OCV profile by using pre-stored half-cell SOC-OCV profiles to calculate the middle of life (MOL) full-cell SOC-OCV profile, updating the profile quickly by determining the available ranges and capacities based on the beginning of life (BOL) data, and integrating current measurements to reflect degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If repeated measurements and long experiments are conducted to generate a new SOC-OCV profile reflecting degradation, then the accuracy of the SOC-OCV profile is improved, but the time required for generation increases significantly

Engineering Contradiction:

Improveaccuracy of SOC-OCV profileVSAvoidtime required for generation

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-storing half-cell SOC-OCV profiles and battery parameters before degradation occurs. These pre-collected data serve as a foundation that eliminates the need for extensive new measurements when updating the full-cell SOC-OCV profile, thus reducing the time required while maintaining accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses copying by creating the full-cell SOC-OCV profile from pre-existing half-cell SOC-OCV profiles through mathematical combination rather than direct measurement. This copying approach from half-cell data to full-cell data significantly reduces the experimental time while preserving the essential degradation characteristics.

Inventive Principle:

Principle #26Copying

2Reliability

If extensive experimental data collection is performed to update the SOC-OCV profile, then the reliability of the degradation reflection is improved, but the complexity of the update process increases

Engineering Contradiction:

Improvereliability of degradation reflectionVSAvoidcomplexity of update process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the battery system into half-cell components (positive electrode half-cell and negative electrode half-cell) and maintaining separate SOC-OCV profiles for each. This segmentation allows independent management and updating of each electrode's characteristics, simplifying the overall update process while reliably capturing degradation effects.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies universality by using the same pre-stored half-cell SOC-OCV profiles for multiple purposes: both for initial full-cell profile generation and for ongoing degradation updates. This multi-functional use of the half-cell data reduces the need for separate experimental procedures, thereby reducing complexity while maintaining reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If a new SOC-OCV profile is generated through repeated measurements, then the profile reflects the current degradation state, but the ease of operation for updating the profile deteriorates

Engineering Contradiction:

Improveprofile reflects degradation stateVSAvoidease of update

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent applies self-service by enabling the system to automatically update the full-cell SOC-OCV profile using pre-stored half-cell data and mathematical relationships, without requiring manual experimental intervention. This automated approach maintains accurate degradation reflection while significantly improving the ease of operation for profile updates.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent applies preliminary action by pre-storing all necessary half-cell SOC-OCV profiles and battery parameters before degradation occurs. This preliminary preparation enables simple, automated updates later by merely combining the pre-stored data with current measurements, making the update process easy to operate while ensuring the profile accurately reflects degradation.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP3674728B1Method and apparatus for estimating SOC-OCV profile

Publication Date: 2024.09.11 LG ENERGY SOLUTION LTD

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AI summary

To conform with the 150 word limit, we suggest using the following as an abstract: An apparatus estimating a state of charge (SOC)-open circuit voltage (OCV) profile, including: a storage unit storing: a beginning of life (BOL) positive electrode (PE) half-cell SOC-OCV profile and available range (AR), a BOL negative electrode (NE) half-cell SOC-OCV profile and AR, and a BOL full-cell SOC-OCV profile and total capacity (TC), and a control unit estimating a full-cell SOC-OCV profile at middle of life (MOL), including: an AR determination module for: calculating an MOL full-cell TC while a secondary battery is fully charged/discharged at MOL, and determining the MOL PE and NE ARs so a ratio of the MOL to the BOL full-cell TCs equals a ratio of the MOL to the BOL PE ARs and a ratio of the MOL to the BOL NE ARs, and a profile management module for: estimating, as an MOL full-cell SOC-OCV profile, a differential profile, and updating the BOL full-cell SOC-OCV profile.