Battery EOL Prediction Using Diagnostic Cycle Electrochemical Data

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Solution Overview

Problem

Current battery life prediction systems for electric vehicles are inefficient, requiring extensive cycles and time frames to estimate end-of-life (EOL), which hampers maintenance, product design, and research due to the reliance on charge and discharge cycles.

Innovation Solution

A prediction system that utilizes diagnostic cycles to measure electrochemical data, determines features associated with battery degradation, and employs a machine learning model to accurately predict EOL, thereby accelerating testing and improving estimation accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If numerous charge and discharge cycles are used to predict battery life, then prediction accuracy is improved, but testing time and productivity are worsened

Engineering Contradiction:
Improveprediction accuracyVSAvoidtesting speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by performing diagnostic cycles with specific electrochemical reactions before full lifecycle testing to pre-identify degradation features. This preliminary characterization allows the system to establish baseline degradation patterns early, enabling more accurate predictions without requiring thousands of complete charge-discharge cycles, thus resolving the contradiction between prediction accuracy and testing time

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes testing parameters by using diagnostic cycles with specific electrochemical reactions (such as rate capability tests, impedance spectroscopy, and partial charge-discharge cycles) instead of traditional full lifecycle charge-discharge cycles. These parameter changes enable the extraction of degradation features at different states of charge and rates, improving prediction accuracy while significantly reducing the number of cycles required

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If extended time frames are used for battery testing, then degradation measurement accuracy is improved, but maintenance and research efficiency are worsened

Engineering Contradiction:
Improvedegradation measurement accuracyVSAvoidtesting duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the mechanical time-based degradation measurement system with an electrochemical reaction-based measurement system. By using specific electrochemical reactions (such as lithium plating, dendrite formation, and SEI layer growth) as proxies for degradation, the system can measure degradation mechanisms directly through electrochemical signals rather than waiting for long-term capacity fade, thus improving measurement accuracy while reducing testing duration

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces electrochemical reactions as intermediary processes that mediate between the battery's internal degradation mechanisms and external measurement. These reactions (such as cyclic voltammetry, electrochemical impedance spectroscopy, and rate capability tests) serve as intermediaries that amplify and make observable the subtle degradation processes occurring inside the battery, enabling accurate degradation measurement without extended time frames

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If traditional charge-discharge cycles are used, then battery life prediction is achieved, but system complexity and cost are increased

Engineering Contradiction:
Improvebattery life predictionVSAvoidtesting system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and isolates specific degradation features from the complex battery system by using targeted electrochemical reactions. Instead of monitoring all possible parameters throughout thousands of cycles, the system extracts key degradation indicators (such as lithium inventory loss, active material degradation, and impedance changes) through specific electrochemical tests, simplifying the overall testing system while maintaining prediction reliability

Inventive Principle:
Principle #2Taking out (Extraction)

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 system enables more precise and rapid estimation of battery life by identifying degradation features through diagnostic cycles, allowing for better prediction of EOL across varying operating conditions, thus enhancing maintenance, research, and reducing costs.

Implementation Method 1

measure electrochemical data of a battery cell associated with an electrochemical reaction triggered by a test during a diagnostic cycle

Methodology Applied
Scientific EffectElectrochemical reaction:

Data Source

PatentUS11768249B2Systems and methods for predicting battery life using data from a diagnostic cycle
Publication Date: 2023.09.26 TOYOTA JIDOSHA KK
  • US11768249B2 patent drawing
  • US11768249B2 patent drawing
  • US11768249B2 patent drawing

AI summary

System, methods, and other embodiments described herein relate to improving the estimation of battery life. In one embodiment, a method includes measuring electrochemical data of a battery cell associated with an electrochemical reaction triggered by a test during a diagnostic cycle. The method also includes determining a feature associated with the degradation of the battery cell from the electrochemical data. The method also includes predicting an end-of-life (EOL) of the battery cell by using the feature in a machine learning (ML) model.