Parallel Transformer Charge Equalization for Battery Arrays

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Solution Overview

Problem

Existing charge equalization apparatuses face manufacturing difficulties and performance limitations as the number of series-connected battery cells increases, particularly due to the need for a single transformer with multiple primary windings and challenges in managing voltage stress and saturation.

Innovation Solution

A charge equalization apparatus using multiple transformers, each with its own primary and secondary windings, connected in parallel, allowing for independent core winding and reduced voltage stress on switches, facilitating flexible spatial arrangement and improved manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single transformer with multiple primary windings is used to handle a large number of series-connected battery cells, then charge equalization can be achieved, but manufacturing complexity and difficulty increase significantly

Engineering Contradiction:
Improvecharge equalization capabilityVSAvoidtransformer manufacturing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent divides the single transformer into multiple independent transformers, each handling a subset of battery cells. This segmentation reduces the complexity of winding multiple primary windings around a single core, making manufacturing more feasible while maintaining charge equalization capability across the entire battery array.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines multiple independent transformers with parallel-connected secondary windings to achieve the function of a single large transformer. The secondary windings are connected in parallel to provide a common output, while each transformer handles its own primary windings connected to specific battery cells, thus simplifying individual transformer construction.

Inventive Principle:
Principle #5Merging (Combining)

2Quantity of substance

If the number of series-connected battery cells increases, then battery capacity and energy supply capability improve, but voltage stress on switches and transformer saturation risks increase

Engineering Contradiction:
Improvebattery capacityVSAvoidvoltage stress on switches
Core Design Contradiction:
Quantity of substanceVSStress or pressure

Solution Approach 1:

The patent segments the battery array into multiple groups, each connected to a separate transformer-primary winding combination. This distribution reduces the voltage stress on individual switches and transformers, as each component only needs to handle the voltage of its assigned battery cells rather than the entire series string.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-series architecture to a multi-parallel architecture, adding a dimensional aspect to the system design. Multiple transformers operate in parallel, each handling a portion of the total battery capacity, thereby distributing voltage stress across multiple components rather than concentrating it in a single path.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If multiple primary windings are wound around a single common core, then charge equalization across all battery cells can be achieved, but manufacturing feasibility decreases

Engineering Contradiction:
Improvecharge equalization performanceVSAvoidtransformer assembly feasibility
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent separates the single common core into multiple independent cores, each supporting its own primary and secondary windings. This segmentation makes the winding process more manageable and reduces assembly complexity, while the parallel connection of secondary windings ensures that charge equalization performance is maintained across all battery cells.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses multiple copies of a standardized transformer module, each with its own core and windings. This modular copying approach simplifies manufacturing by allowing standardized production of identical units, which are then assembled in parallel configurations to achieve the required charge equalization capability.

Inventive Principle:
Principle #26Copying

4Power

If a large number of battery cells are connected in series, then voltage output and power supply capability increase, but the ability to maintain balanced charge state across all cells becomes more difficult

Engineering Contradiction:
Improvepower supply capabilityVSAvoidcharge balance maintenance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent segments the series-connected battery cells into multiple groups, with each group connected to a separate transformer. This segmentation enables independent control and monitoring of charge states in different cell groups, making it easier to detect and correct imbalances while maintaining high voltage output through the series configuration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a control system that monitors the charge state of individual battery cells or groups and adjusts the operation of switches and transformers accordingly. This feedback mechanism enables the system to maintain balanced charge states across all cells, even as the total number of series-connected cells increases and power supply capability grows.

Inventive Principle:
Principle #23Feedback

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 efficient charge equalization while maintaining performance, reducing manufacturing complexity and preventing transformer saturation, even with a large number of battery cells, by distributing voltage stress and allowing for flexible design.

Implementation Method 1

a plurality of battery cells B1 to BN connected in series is connected in parallel with primary windings M11 to M1N of transformers T1 to TN, and secondary windings M21 to M2N of the transformers T1 to TN are connected in parallel with each other

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2036186B1Charge equalization apparatus with parallel connection of secondary windings of multiple transformers
Publication Date: 2020.03.04 SK INNOVATION CO LTD
  • EP2036186B1 patent drawingFigure 1
  • EP2036186B1 patent drawingFigure 2
  • EP2036186B1 patent drawingFigure 3

AI summary

The present invention relates, in general, to a charge equalization apparatus with series-connected battery cells and, more particularly, to a charge equalization apparatus, in which series-connected battery cells (Bl to BN) are connected in parallel with the primary windings (Mi l to MlN) of transformers (Tl to TN), switches (Sl to SN) for controlling the flow of current of the primary windings are connected in series with the primary windings (Ml 1 to MlN), and multiple secondary windings (M21 to M2N) corresponding to the primary windings are connected in parallel with each other.