Integrated Bidirectional Charger for Split Battery Voltage Matching

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Solution Overview

Problem

Existing battery chargers for electric vehicles often have inefficiencies due to their fixed configurations, which may not optimize power transfer across varying power requirements and battery voltages.

Innovation Solution

A system comprising a DC-DC converter with configurable high voltage and low voltage connections for multiple batteries, along with a battery charger that includes this converter. The system features multiple buck-boost converters and transformers, controlled by a controller to manage power transfer across different operational modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a fixed configuration battery charger is used, then the device complexity is reduced, but the efficiency for different power requirements deteriorates

Engineering Contradiction:
Improvecharging efficiencyVSAvoidconverter configuration
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent implements a configurable DC-DC converter that can dynamically switch between different connection modes (series/parallel) and operational modes (charging/discharging) based on real-time power requirements and battery states. This dynamic reconfiguration capability allows the system to optimize charging efficiency for different scenarios while managing device complexity through controlled adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The converter is designed to perform multiple functions including charging, discharging, power transfer between batteries, and voltage matching across different configurations. By integrating these diverse functions into a single reconfigurable device, the system achieves high efficiency across various operational scenarios without requiring separate dedicated hardware for each function.

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

2Reliability

If multiple separate converters are used for different batteries, then the reliability is improved, but the device complexity increases

Engineering Contradiction:
Improvepower transfer reliabilityVSAvoidconverter count
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple converter functions into a single integrated DC-DC converter that can simultaneously or sequentially serve multiple batteries. The unified converter includes configurable connections to first and second high voltage batteries and first and second low voltage batteries, reducing the total number of components while maintaining reliable power transfer through centralized control and monitoring.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

While integrating multiple functions, the converter is segmented into distinct operational modes and configurable connection paths for different battery combinations. This segmentation allows the control system to selectively activate appropriate circuits for specific charging or discharging scenarios, ensuring reliable operation without requiring all components to be active simultaneously, thus reducing overall complexity.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If a configurable converter is used, then the adaptability is improved, but the device complexity increases

Engineering Contradiction:
Improveoperational modesVSAvoidconverter structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The converter employs dynamic reconfiguration capabilities that allow it to adapt between different connection modes (series/parallel) and operational modes (charging/discharging) based on real-time system requirements. This dynamic approach enables high adaptability while managing complexity through automated control logic that selectively activates only the necessary circuits for each operational scenario.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The device is designed as a universal converter that can perform charging, discharging, power transfer between batteries, and voltage matching across multiple configurations. By consolidating these diverse functions into a single reconfigurable device with standardized interfaces, the system achieves maximum adaptability without proportionally increasing structural complexity.

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

4Productivity

If high power density is maintained, then the productivity is improved, but the weight increases

Engineering Contradiction:
Improvepower densityVSAvoidcharger weight
Core Design Contradiction:
ProductivityVSWeight of moving object

Solution Approach 1:

The patent integrates multiple converter functions and battery management capabilities into a single compact DC-DC converter unit. By combining charging, discharging, and power transfer functions in one device rather than using separate converters, the system achieves high power density while minimizing the total weight of the charging system.

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 configuration enhances efficiency by allowing optimal power transfer across multiple battery voltages and operational modes, reducing component count, weight, and cost while maintaining high power density.

Implementation Method 1

an alternating current (AC) to direct current (DC) converter (AC-DC converter), the AC-DC converter connectable to a line voltage

Methodology Applied
Scientific EffectRectification: Diode

Implementation Method 2

a DC to DC converter (DC-DC converter) connected to the AC-DC converter, the DC-DC converter including: a first high voltage buck-boost converter having a secondary side connectable to a first high voltage battery

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4550644A1Systems and methods for integrated converter for bidirectional onboard battery charger for split battery
Publication Date: 2025.05.07 BORGWARNER US TECHNOLOGIES LLC
  • EP4550644A1 patent drawingFigure 1
  • EP4550644A1 patent drawingFigure 2
  • EP4550644A1 patent drawingFigure 3

AI summary

A system includes: an AC-DC converter; and a DC-DC converter, the DC-DC converter including: a first high voltage buck-boost converter having a secondary side connectable to a first high voltage battery; a second high voltage buck-boost converter having a secondary side connectable to a second high voltage battery; a first low voltage buck-boost converter having a secondary side connectable to a first low voltage battery; a second low voltage buck-boost converter having a secondary side connectable to a second low voltage battery; and one or more transformers having a primary side connected to the AC-DC converter and a secondary side connected to each of a primary side of the first high voltage buck-boost converter, a primary side of the second high voltage buck-boost converter, a primary side of the first low voltage buck-boost converter, and a primary side of the second low voltage buck-boost converter.