Portable AC/DC Charging Module for Off-Station EV DC Charging

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Solution Overview

Problem

Existing electric vehicles require onboard converters for both AC and DC charging, limiting space, weight, and cost efficiency, and lack a portable solution for charging away from suitable DC infrastructure.

Innovation Solution

A portable module with integrated AC/DC converter combines direct current from three phases, eliminating the need for onboard converters and allowing standalone DC charging at any single-phase AC power supply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If onboard converters are installed in electric vehicles for both AC and DC charging, then both AC and DC charging options are available, but vehicle weight and space requirements increase

Engineering Contradiction:
Improvecharging option availabilityVSAvoidvehicle weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The invention extracts the AC/DC converter from the vehicle's onboard equipment and relocates it to a portable charging module. This allows the vehicle to eliminate the onboard converter while retaining DC charging capability through the portable module, thereby reducing vehicle weight and space requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The portable charging module serves multiple functions: it can be used for DC charging at stationary charging stations, for AC charging at home or public AC stations, and can charge multiple different vehicles. This multi-functionality replaces the need for separate onboard converters for both AC and DC charging.

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

2Adaptability or versatility

If onboard converters are installed in electric vehicles for both AC and DC charging, then both charging modes are supported, but manufacturing costs increase

Engineering Contradiction:
Improvecharging mode supportVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

By extracting the AC/DC converter from the vehicle and placing it in a portable module, the vehicle manufacturer eliminates the need to install and integrate expensive onboard converters, thereby reducing manufacturing costs while still supporting both AC and DC charging through the portable module.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The portable module is designed to be a self-contained unit that the vehicle owner possesses and operates independently. It contains its own AC/DC converter and charging control electronics, eliminating the need for the vehicle manufacturer to provide these components, thus reducing manufacturing costs.

Inventive Principle:
Principle #25Self-service

3Weight of moving object

If vehicles are equipped only with DC charging capability, then onboard converter circuits are eliminated, but vehicles become dependent on DC charging stations and cannot charge at AC locations

Engineering Contradiction:
Improveonboard converter weightVSAvoidcharging location flexibility
Core Design Contradiction:
Weight of moving objectVSAdaptability or versatility

Solution Approach 1:

The portable charging module acts as an intermediary device that bridges the gap between AC power sources and DC charging requirements. It contains the AC/DC converter needed for DC charging, allowing the vehicle to charge from AC sources at home or public AC stations without requiring the vehicle itself to have built-in conversion capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The charging system becomes dynamic and adaptable: the vehicle can use DC charging at stationary DC charging stations when the portable module is docked, and can use AC charging when the portable module is used independently. This dynamic configuration provides charging location flexibility without requiring fixed onboard conversion equipment.

Inventive Principle:
Principle #15Dynamics

4Adaptability or versatility

If a portable charging module with AC/DC converter is used, then standalone DC charging is possible at any single-phase AC power supply, but the module must handle all conversion functions independently

Engineering Contradiction:
Improvestandalone charging capabilityVSAvoidmodule complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The portable module merges multiple functions into a single integrated unit: AC/DC conversion, charging control, communication protocols, and protection circuits are all combined in one compact module. This integration, while increasing module complexity, eliminates the need for separate onboard equipment in the vehicle and provides standalone charging capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The portable module is designed with a nested structure where the AC/DC converter and charging electronics are integrated within a compact housing that can be docked into or carried with the vehicle. This nested design allows the module to function independently when needed while efficiently utilizing space when docked at a charging station.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

Enables fast, cost-effective DC charging anywhere, reducing weight and space requirements by integrating phase-specific converters in a portable module, independent of stationary stations.

Implementation Method 1

at least two AC/DC converters, wherein an AC/DC converter is designed as part of a portable module

Methodology Applied
Scientific EffectAC/DC conversion:

Data Source

PatentEP4021756B1Charging system for DC charging of the traction battery of an electrically driven vehicle
Publication Date: 2025.10.01 KOSTAL AUTOMOBIL ELECTRIC GMBH & CO KG
  • EP4021756B1 patent drawingFigure 1
  • EP4021756B1 patent drawingFigure 2

AI summary

The invention relates to a charging system for DC charging of the traction battery of an electrically powered motor vehicle, comprising a stationary charging station, which is connected to a three-phase AC voltage or a three-phase alternating current supply network, an AC/DC converter being provided for each of the three phases, characterised according to the invention in that the AC/DC converter for one of the three phases is designed as part of a portable module which can be removed from the charging station, which module is provided with a housing which can be separated from the charging station and in which further electronic components are provided which supplement this to provide an autonomous, single-phase charger.