Battery Management Using Differential Capacity for Over-Potential Control

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Solution Overview

Problem

As batteries degrade, increased over-potential during charging accelerates degradation, leading to lithium metal deposition and potential internal short circuits.

Innovation Solution

A battery management system that updates over-potential management information based on previous charging cycles and differential capacity curves to adjust charge conditions and prevent excessive over-potential.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If constant-current charging is performed at maximum C-rate, then charging speed is improved, but over-potential increases causing lithium deposition and internal short circuits

Engineering Contradiction:

Improvecharging speedVSAvoidbattery safety

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The charging current is dynamically adjusted based on real-time monitoring of differential capacity curves. The system transitions from static maximum C-rate charging to adaptive current modulation, reducing current when over-potential risk is detected and maintaining maximum current when safe, thereby resolving the contradiction between charging speed and battery safety

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system implements feedback control by continuously monitoring voltage, current, and differential capacity during charging. The measured differential capacity curve is compared against reference values to detect over-potential conditions, and the charging current is adjusted in response to this feedback, enabling safe maximum-speed charging

Inventive Principle:

Principle #23Feedback

2Use of energy by moving object

If battery is charged repeatedly at high rates, then energy throughput is improved, but polarization increases accelerating degradation

Engineering Contradiction:

Improveenergy throughputVSAvoidbattery lifespan

Core Design Contradiction:

Use of energy by moving objectVSDuration of action of stationary object

Solution Approach 1:

The system performs preliminary detection of over-potential risk by analyzing the differential capacity curve before it leads to severe degradation. By identifying the onset of excessive polarization early in the charging process, the system can take preventive action by reducing current, thereby protecting battery lifespan while maximizing energy throughput

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the charging parameter (current rate) based on the state of the battery as revealed by differential capacity analysis. When the battery is in a healthy state, maximum current is applied for high energy throughput. When polarization indicators change to show degradation risk, the current parameter is reduced to protect battery lifespan

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 effectively suppresses over-potential, reducing lithium deposition and preventing internal short circuits, thereby extending battery life.

Implementation Method 1

a voltage sensor configured to generate a voltage sensing signal indicating a voltage of a battery

Methodology Applied

Scientific EffectElectrochemical potential:

Implementation Method 2

a current sensor configured to generate a current sensing signal indicating a current flowing through the battery

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

lithium batteries have little or no memory effect, and thus they are gaining more attention than nickel-based batteries for their advantages that recharging can be done whenever it is convenient

Methodology Applied

Scientific EffectElectrochemical reactions:

Implementation Method 4

While a battery is being charged, polarization occurs in the battery. The polarization depends on a plurality of resistance components (for example, Ohm resistance, electric charge transfer, diffusion resistance) of the battery

Methodology Applied

Scientific EffectPolarization: Polarisation

Implementation Method 5

when the voltage of the negative electrode of the battery drops below 0 V due to the over-potential, lithium metal deposition rapidly occurs on the negative electrode surface

Methodology Applied

Scientific EffectMetal deposition: Deposition (physical)

Data Source

PatentUS12344120B2Battery management system, battery management method, battery pack, and electric vehicle

Publication Date: 2025.07.01 LG ENERGY SOLUTION LTD

AI summary

A battery management system includes a sensor to sense voltage and current of a battery, memory to store over-potential management information including reference peak and reference peak voltage values, and a controller to command constant-current charging using a maximum allowable C-rate to a charging circuit when the reference peak value is equal to or larger than a threshold peak value, in response to a charge request, determine a differential capacity curve indicating a correlation between the voltage and differential capacity of the battery within a range based on the sensed voltage and current during the charging, determine main peak and main peak voltage values indicating differential capacity and voltage of a peak of the differential capacity curve, respectively, and update the reference peak and reference peak voltage values to equal the main peak and main peak voltage values, when the main peak value is less than the threshold peak value.