Charge Equalization Using Regulated Voltage Source and Bidirectional Switches

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Solution Overview

Problem

Existing charge equalization apparatuses for series-connected batteries are complex, voluminous, and costly, requiring voltage sensing units and analog-digital converters, which increases complexity and production costs, and subjects components to high voltage stress.

Innovation Solution

An automatic charge equalization apparatus using a regulated voltage source and bidirectional switch blocks, without voltage sensing units or analog-digital converters, connects each battery in a series-connected battery string to a regulated voltage source, controlled by a microprocessor to maintain average voltage across all batteries, using bidirectional DC-DC converters and PWM signals to manage charge equalization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If voltage sensing units and analog-digital converters are used to measure battery voltage and control charge equalization, then charge equalization control precision is improved, but device complexity and production cost increase

Engineering Contradiction:

Improvevoltage measurement precisionVSAvoidapparatus complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the voltage sensing unit and analog-digital converter from the charge equalization apparatus. Instead of measuring voltage and converting it to digital signals, the system directly uses the battery string's voltage characteristics through bidirectional switches to achieve charge equalization without these complex components.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the electronic measurement and conversion system (sensing units and ADCs) with a direct voltage-based control mechanism. The microprocessor controls bidirectional switches that directly respond to voltage differences in the battery string, substituting complex electronic measurement with a simpler voltage-responsive switching system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

Engineering Contradiction:

Improvevoltage measurement precisionVSAvoidproduction cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

3Extent of automation

If components are subjected to high voltage stress in series-connected batteries, then charge equalization capability is improved, but component reliability decreases

Engineering Contradiction:

Improvecharge equalization capabilityVSAvoidcomponent reliability

Core Design Contradiction:

Extent of automationVSReliability

Solution Approach 1:

The patent segments the battery string into individual battery units, each with its own bidirectional switch. This segmentation allows each component to handle only the voltage of a single battery unit rather than the total string voltage, reducing voltage stress on individual components while maintaining charge equalization capability across the entire string.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces bidirectional switches as intermediary components between the battery units and the control system. These switches act as mediators that isolate individual battery units from the high voltage string, protecting components from excessive voltage stress while enabling controlled charge equalization through selective switching.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 reduces the complexity and cost of the charge equalization apparatus by eliminating the need for voltage sensing units and analog-digital converters, allowing flexible design changes and efficient charge equalization, while reducing component stress and enabling easy adaptation to battery degradation.

Implementation Method 1

bidirectional DC-DC converter connected between the series-connected battery string and the regulated voltage source

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2384530B1Charge equalization apparatus for series-connected battery string using regulated voltage source

Publication Date: 2018.07.04 SK INNOVATION CO LTD

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AI summary

An automatic charge equalization apparatus using a regulated voltage source according to the present invention comprises a battery module having a plurality of batteries connected in series; a battery string having M (natural number of M=2) battery modules connected in series: a regulated voltage source which is provided for each battery module and outputs and maintains an average voltage of the battery string; a bidirectional switch block which is provided for each battery module between the battery module and the regulated voltage source to connect each battery to an output of the regulated voltage source by forming a parallel current moving path to each battery composing the battery module; and a microprocessor controlling the bidirectional switch block, wherein each battery composing the battery module shares the regulated voltage source by the bidirectional switch block and the microprocessor controls the bidirectional switch block to successively connect the batteries composing the battery module with the regulated voltage source.