Two-Stage Charge Equalization for Series Battery Strings

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Solution Overview

Problem

Existing charge equalization systems for series-connected batteries face complexity and increased production costs due to high voltage stress on components, leading to inefficiencies and degradation over time.

Innovation Solution

A two-stage DC/DC converter system where batteries are classified into modules, sharing a single DC/DC converter to reduce voltage stress and complexity, with a microprocessor-controlled charge control switch module and multiplexer for efficient charge equalization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If each battery is equipped with an independent charge equalizing apparatus, then charge equalization can be performed for each battery, but the complexity and volume of the apparatus increase, decreasing productivity and increasing production costs

Engineering Contradiction:
Improvecharge equalization effectivenessVSAvoidapparatus complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple charge equalizing apparatuses are merged into a single shared apparatus that can sequentially serve multiple batteries. The control unit manages the switching between batteries, allowing one apparatus to perform charge equalization for several batteries rather than each battery having its own dedicated apparatus, thereby reducing overall system complexity and cost.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The charge equalizing apparatus is designed with multi-functionality to serve multiple batteries through sequential operation. The control unit enables the apparatus to switch between different batteries based on their charge states, making a single apparatus universally applicable to multiple batteries rather than being dedicated to one specific battery.

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

2Reliability

If each battery is equipped with an independent charge equalizing apparatus, then charge equalization can be performed for each battery, but the volume of the apparatus increases, decreasing productivity

Engineering Contradiction:
Improvecharge equalization effectivenessVSAvoidapparatus volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

Multiple charge equalizing apparatuses are merged into a single shared apparatus that can sequentially serve multiple batteries. The control unit manages the switching between batteries, allowing one apparatus to perform charge equalization for several batteries rather than each battery having its own dedicated apparatus, thereby reducing overall system complexity and cost.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If charge equalization apparatus components withstand high voltage stress, then individual battery equalization is possible, but production costs increase

Engineering Contradiction:
Improveindividual battery control capabilityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Multiple charge equalizing apparatuses are merged into a single shared apparatus that can sequentially serve multiple batteries. The control unit manages the switching between batteries, allowing one apparatus to perform charge equalization for several batteries rather than each battery having its own dedicated apparatus, thereby reducing overall system complexity and cost.

Inventive Principle:
Principle #5Merging (Combining)

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 simplifies the charge equalization apparatus, reduces voltage stress on components, and improves charging efficiency by sharing DC/DC converters among battery modules, thereby minimizing energy consumption and production costs.

Implementation Method 1

a first DC/DC converter whose input is an overall potential of the battery string and whose output is a potential lower than a potential inputted

Methodology Applied
Scientific EffectDC/DC conversion: Electromagnetic Induction

Data Source

PatentEP2201659B1Two-stage charge equalization method and apparatus for series-connected battery string
Publication Date: 2016.05.25 SK INNOVATION CO LTD
  • EP2201659B1 patent drawingFigure 1
  • EP2201659B1 patent drawingFigure 2
  • EP2201659B1 patent drawingFigure 3

AI summary

A two- stage charge equalization apparatus for a series-connected battery string comprises a battery module having a plurality of batteries connected in series; a battery string having M (M=2) battery modules connected in series; M charge control switch modules connected in parallel to each of the M battery modules; M second DC/DC converters connected to each of the M charge control switch modules,- a single first DC/DC converter connected to the M second DC/DC converter; and a microprocessor controlling the charge control switch module, wherein the first DC/DC converter is inputted with an overall potential of the battery string and outputs a potential lower than the potential inputted and each of batteries composing the battery module shares the second DC/DC converter using the charge control switch module.