High Current Battery Balancing Architecture

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Solution Overview

Problem

Current battery cell balancing systems, particularly in lithium-ion batteries, face limitations in balancing power and efficiency, leading to uneven charging and reduced battery lifespan due to high costs and complex architectures, with existing methods either restricting charging current or requiring prolonged charging times.

Innovation Solution

An electric power supply unit with an integrated Battery Management System (BMS) that includes active and passive balancing elements, using a DC/DC converter for active balancing and a variable resistive load for passive balancing, along with a switching device to manage high currents efficiently, allowing for simultaneous monitoring and balancing of cell charge levels to achieve homogeneous charging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If direct connection architecture is used where BMS is connected to individual cells, then device complexity is reduced, but balancing power is limited

Engineering Contradiction:
Improveconnection complexityVSAvoidbalancing power
Core Design Contradiction:
Device complexityVSPower

Solution Approach 1:

The system segments the balancing function into two parts: a centralized DC/DC converter handles high-current balancing operations, while the BMS manages monitoring and control. This segmentation allows the BMS to remain simple while achieving high balancing power through the dedicated DC/DC converter module.

Inventive Principle:
Principle #1Segmentation

2Reliability

If control and balancing elements are applied to each individual cell, then balancing performance is improved, but device complexity and cost increase

Engineering Contradiction:
Improvebalancing performanceVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The DC/DC converter acts as an intermediary between the BMS and the battery cells for balancing operations. The BMS sends control signals to the DC/DC converter, which then executes the high-current balancing on the cells. This intermediary approach allows sophisticated balancing performance without requiring complex circuitry at each cell level.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If charging current is reduced according to charge level of individual cells, then cell charge homogeneity is improved, but charging time increases

Engineering Contradiction:
Improvecharge homogeneityVSAvoidcharging time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The system dynamically switches between two charging modes: fast charging mode for cells that are not yet balanced, and controlled balancing mode for cells approaching charge equality. The DC/DC converter enables high-current operation during balancing, dynamically adjusting current levels based on real-time cell voltage measurements to achieve both speed and homogeneity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the charging current parameter based on the balancing needs of individual cells. During active balancing, high current is applied through the DC/DC converter to rapidly equalize cell charges. Once cells are balanced, the system transitions to standard charging parameters, maintaining both speed and charge homogeneity throughout the charging process.

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 solution enables faster, more efficient battery charging with improved cost-effectiveness and scalability, maximizing battery life and performance by optimizing balancing times and reducing energy losses, while maintaining compactness and low costs.

Implementation Method 1

using a DC/DC converter for active balancing

Methodology Applied
Scientific EffectDC/DC conversion: Electromagnetic Induction

Implementation Method 2

using a variable resistive load for passive balancing

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3840172A1Architecture of a high current balancing system for batteries
Publication Date: 2021.06.23 FLASH BATTERY SRL
  • EP3840172A1 patent drawingFigure 1~2
  • EP3840172A1 patent drawingFigure 3
  • EP3840172A1 patent drawingFigure 4

AI summary

The present invention relates to a utility power supply unit (1) including at least one battery (2) having two or more cells (4) and a Battery Management System or BMS (8).