Battery Management Using Differential Capacity for Polarization Control

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Solution Overview

Problem

The phase change reaction during battery charging is significantly influenced by polarization, leading to increased overvoltage and rapid battery degradation, which existing technologies have not adequately addressed.

Innovation Solution

A battery management system that determines a differential capacity curve during charging to detect feature points, allowing for tailored protection operations based on polarization levels, including adjusting the reference current and cut-off voltage to mitigate overpolarization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high current rate charging is applied to the battery, then charging speed is improved, but polarization increases causing overvoltage and rapid battery degradation

Engineering Contradiction:
Improvecharging speedVSAvoidbattery degradation
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements dynamic adjustment of charging current based on real-time polarization detection. The control unit continuously monitors the differential capacity curve and adjusts the charging current rate dynamically - reducing current when polarization exceeds thresholds and restoring it when polarization decreases, thereby optimizing both charging speed and battery longevity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the charging parameter (current rate) based on detected polarization levels. By monitoring特征 points on the differential capacity curve and comparing them against reference values, the system adjusts the charging current to maintain optimal charging speed while preventing excessive polarization that would cause degradation

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If low temperature operation is performed on the battery, then energy loss is reduced, but polarization becomes severer increasing overvoltage

Engineering Contradiction:
Improveself-discharge rateVSAvoidpolarization
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent employs feedback control by continuously monitoring the differential capacity curve during charging and using this information to adjust charging parameters. The control unit detects特征 points and compares them with reference values to determine polarization level, then provides feedback to adjust the charging current, creating a closed-loop system that adapts to temperature conditions

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4156376B1Battery management system, battery management method, battery pack and electric vehicle
Publication Date: 2025.07.16 LG ENERGY SOLUTION LTD
  • EP4156376B1 patent drawingFigure 1
  • EP4156376B1 patent drawingFigure 2
  • EP4156376B1 patent drawingFigure 3

AI summary

A battery management system according to the present disclosure includes a voltage sensor to generate a voltage signal indicating a voltage of a battery, a current sensor to generate a current signal indicating a current flowing through the battery, and a control unit to record a voltage history and a current history of the battery based on the voltage signal and the current signal at a predetermined time interval during constant current charging of the battery. The control unit determines a differential capacity curve indicating a correlation between the voltage of the battery and a differential capacity in a reference voltage range. The control unit performs a first protection operation for the battery by comparing a first characteristic voltage of a main feature point with a reference voltage when the main feature point is detected from the differential capacity curve.