Battery Module SoC Equalization via Closed Current Supply Circuit

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Solution Overview

Problem

Battery modules with imbalanced voltages, due to production deviations and temperature differences, lead to decreased capacity and accelerated aging when used together, necessitating a solution for equalizing state of charge (SoC) to prolong lifespan.

Innovation Solution

An apparatus and method that control switching units in cell module controllers (CMCs) based on diagnosed abnormalities, forming a closed equalization current supply circuit through a battery module controller (BMC) to equalize SoC by supplying an equalization current to abnormal battery modules.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If battery modules with imbalanced voltages are joined and used, then the system can operate with high capacity, but the available capacities and power decrease and aging is accelerated

Engineering Contradiction:
Improvebattery capacityVSAvoidbattery lifespan
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent implements self-service by enabling battery modules to automatically equalize their own voltages through internal switching units and control circuits. The system detects voltage imbalances and activates equalization current paths within the battery pack, allowing modules to correct their own deviations without external intervention, thus maintaining both high capacity and extended lifespan

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent employs feedback mechanisms where voltage sensors continuously monitor the state of charge of individual battery modules, and the control unit processes this information to determine which modules require equalization. This closed-loop feedback system dynamically adjusts switching unit states to maintain voltage balance, preventing capacity degradation and extending battery lifespan while preserving overall system capacity

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If voltage imbalance occurs in battery modules, then production deviations and temperature differences cause SoC variation, but joining modules with imbalanced voltages decreases available capacity and power

Engineering Contradiction:
Improvebattery module compatibilityVSAvoidavailable power
Core Design Contradiction:
Adaptability or versatilityVSPower

Solution Approach 1:

The patent applies local quality by implementing individualized control for each battery module, with dedicated switching units and voltage sensors for each module. This allows the system to address voltage imbalances locally in specific modules without affecting the entire battery pack, maintaining overall power output while accommodating variations in production and temperature conditions across different modules

Inventive Principle:
Principle #3Local quality

3Duration of action of stationary object

If an equalization current supply circuit is formed to equalize SoC, then battery lifespan is prolonged, but device complexity increases due to switching units and control circuits

Engineering Contradiction:
Improvebattery lifespanVSAvoidcontrol circuit complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The patent merges the equalization function with the existing battery management system by integrating switching units and control circuits into the standard module architecture. The equalization current supply circuit shares common components such as bus bars, connection terminals, and control processors with normal charging/discharging operations, thereby extending battery lifespan without proportionally increasing device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The switching units and control circuits designed for equalization are configured to perform multiple functions including normal charge/discharge control, voltage monitoring, and equalization current regulation. This multi-functionality reduces the need for separate dedicated equalization hardware, extending battery lifespan while minimizing the increase in device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3540900B1Apparatus and method for battery module equalization
Publication Date: 2025.06.25 LG ENERGY SOLUTION LTD
  • EP3540900B1 patent drawingFigure 1
  • EP3540900B1 patent drawingFigure 2
  • EP3540900B1 patent drawingFigure 3

AI summary

The present invention relates to an apparatus and a method of equalizing a battery module, and more particularly, to an apparatus and a method of equalizing a battery module, which supply an equalization current to a battery module which is diagnosed to have abnormality via an equalization current supply circuit when abnormality is generated in a state of charge (SoC) of one or more battery modules, and equalize the SoC of the one or more battery modules.