Li-Ion Battery Charging Control for Anode Overvoltage Limits

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Solution Overview

Problem

Lithium-ion batteries face issues with lithium plating during charging, leading to reduced lifespan, potential short circuits, and fires, and existing methods lack a precise approach to setting an optimal anode overvoltage limit, resulting in either conservative charging or aggressive aging.

Innovation Solution

A method that involves analyzing signal curves of lithium-ion batteries, comparing them with similar batteries' data to determine an optimized anode overvoltage limit, adjusting it to match average capacity loss, and using AI-based models to calculate optimal charging currents to maintain the anode overvoltage above a set limit, thereby extending battery life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed anode overvoltage limit is used for charging, then charging simplicity is maintained, but battery aging accelerates due to inability to adapt to individual battery characteristics

Engineering Contradiction:
Improveadaptability to battery characteristicsVSAvoidcharging control complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system performs preliminary characterization of each battery's aging behavior by collecting and storing capacity aging data during normal operation. This preliminary action enables the system to establish individualized charging strategies without adding complexity to the actual charging process, as the adaptation work is done in advance during idle periods.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The charging system automatically adapts to each battery's characteristics by using the battery's own operational data to generate personalized charging curves. The system serves itself by leveraging its own collected data to improve charging performance, eliminating the need for external calibration or manual intervention.

Inventive Principle:
Principle #25Self-service

2Productivity

If aggressive charging is applied to reduce charging time, then productivity increases, but battery lifespan decreases due to accelerated aging

Engineering Contradiction:
Improvecharging speedVSAvoidbattery lifespan
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The charging system dynamically adjusts the charging curve based on real-time battery state and historical aging data. Instead of using a static charging protocol, the system continuously adapts the charging parameters to optimize the balance between charging speed and battery preservation, allowing aggressive charging only when safe for the specific battery.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from capacity aging measurements and voltage curve analysis to continuously refine charging strategies. By monitoring the battery's response to charging and comparing it against learned patterns, the system adjusts future charging parameters to maximize both speed and lifespan, creating a closed-loop optimization system.

Inventive Principle:
Principle #23Feedback

3Duration of action of stationary object

If conservative charging is used to extend battery life, then battery lifespan increases, but charging time increases reducing productivity

Engineering Contradiction:
Improvebattery lifespanVSAvoidcharging time
Core Design Contradiction:
Duration of action of stationary objectVSLoss of time

Solution Approach 1:

The system changes charging parameters based on the battery's individual characteristics and state of charge. By analyzing voltage, current, and temperature parameters in real-time and comparing them against learned patterns, the system dynamically adjusts charging rates to achieve optimal balance between speed and battery preservation for each specific situation.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If individualized charging curves are generated for each battery, then charging optimization improves, but data processing complexity increases

Engineering Contradiction:
Improvecharging optimization precisionVSAvoiddata processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system creates simplified representative models of battery behavior by copying and storing characteristic voltage-current-temporal patterns from actual battery responses. These copied patterns serve as templates for comparing against new charging scenarios, enabling precise optimization without processing every raw data point in detail.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP4046228B1Method of adapting an anode overvoltage of a lithium-ion battery and method of improving a state of health (SOH) of the lithium-ion battery
Publication Date: 2023.12.06 ROBERT BOSCH GMBH
  • EP4046228B1 patent drawingFigure 1
  • EP4046228B1 patent drawingFigure 2
  • EP4046228B1 patent drawingFigure 3

AI summary

The invention relates to a method for adjusting an anode overvoltage of a lithium-ion battery (310). The invention furthermore relates to a method for improving a capacity state of health of a lithium-ion battery (310). The invention also relates to a vehicle having at least one lithium-ion battery (310) whose anode overvoltage is adjusted using the method for adjusting the anode overvoltage of the lithium-ion battery (310) and/or whose capacity state of health is improved using the method for improving the capacity state of health of the lithium-ion battery (310). The invention also relates to a fleet management system that is designed to perform the method for adjusting the anode overvoltage of the lithium-ion battery (310) and/or the method for improving the capacity state of health of the lithium-ion battery (310).