Charging Gun Connection Circuit With Direct Relay Power Supply

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Solution Overview

Problem

Current charging guns have a large size, high weight, and high cost due to numerous components, and often experience poor contact and storage inconvenience due to their complex connection circuits.

Innovation Solution

A connection circuit that powers the relay directly from an external power supply, reducing the load on the power supply circuit and minimizing components, thereby lowering cost and size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the relay is powered by the power supply circuit, then the control circuit can be powered, but the power supply circuit becomes complex and large in size

Engineering Contradiction:
Improvepower supply reliabilityVSAvoidpower supply circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the power supply system into two independent parts: the power supply circuit (providing only control power) and the relay coil circuit (directly connected to external power supply). This segmentation eliminates the need for the power supply circuit to handle high-power relay activation, thereby simplifying its design and reducing component count while maintaining reliable power delivery to both control and relay functions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the relay coil power supply function from the main power supply circuit and connects it directly to the external power supply. This extraction removes the burden of providing high current for the relay coil from the power supply circuit, allowing the power supply circuit to be minimized to only what is necessary for control signal generation, thus reducing overall system complexity and size

Inventive Principle:
Principle #2Taking out (Extraction)

2Power

If numerous components are used in the connection circuit, then power conversion requirements are met, but the charging gun becomes large in size and heavy in weight

Engineering Contradiction:
Improvepower conversion capabilityVSAvoidcharging gun weight
Core Design Contradiction:
PowerVSWeight of stationary object

Solution Approach 1:

The patent extracts the high-power switching function from the power supply circuit and assigns it to the relay that is directly powered by the external power supply. This allows the power supply circuit to be dramatically reduced in size, containing only essential components for low-power control signal generation, thereby significantly reducing the overall weight of the charging gun while preserving full power conversion capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a simple, minimalistic power supply circuit design that uses basic, inexpensive components (such as a small transformer and rectifier) rather than complex, heavy-duty power conversion components. This approach achieves sufficient power conversion for control functions while minimizing weight and cost, accepting that the power supply circuit itself does not need to handle high power directly

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Power

If the connection circuit has numerous components, then power conversion is achieved, but the charging gun becomes costly

Engineering Contradiction:
Improvepower conversion capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

By segmenting the power supply system into separate control power and relay power paths, the patent eliminates the need for expensive, high-power integrated power conversion modules in the power supply circuit. The simplified circuit uses inexpensive discrete components, reducing bill of materials cost and assembly complexity while maintaining the required power conversion capability for control functions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adopts a cost-effective approach by using simple, readily available components in the power supply circuit rather than expensive, specialized power management integrated circuits. The minimal component count and use of standard parts significantly reduce manufacturing costs while achieving the necessary power conversion for control signal generation

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Reliability

If the charging plug and power socket have poor contact, then connection reliability decreases, but the complex connection circuit makes storage inconvenient

Engineering Contradiction:
Improveconnection reliabilityVSAvoidstorage convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent extracts the high-current connection function to a dedicated relay contact system that is directly powered by the external power supply, separating it from the control circuitry. This allows the control circuit to be minimized and integrated into the charging gun head, improving portability and storage convenience while the robust relay contacts maintain high connection reliability for power transmission

Inventive Principle:
Principle #2Taking out (Extraction)

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

The solution reduces the size and cost of the charging gun while improving contact reliability and storage convenience by integrating the connection circuit into the charging gun head.

Implementation Method 1

a power supply circuit, which is connected to the external power supply for converting the voltage of the external power supply into a low voltage via power frequency transformation

Methodology Applied
Scientific EffectPower frequency transformation: Electromagnetic Induction

Implementation Method 2

a relay, which includes an input side and an output side, the output side is arranged on the charge-discharge circuit, the input side is connected to the external power supply and the control circuit, and is configured to drive the output side to break or conduct the charge-discharge circuit according to the control signal

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnet

Data Source

PatentEP4693801A1Connection circuit and charging gun
Publication Date: 2026.02.11 BYD CO LTD
  • EP4693801A1 patent drawingFigure 1~2
  • EP4693801A1 patent drawingFigure 3~5
  • EP4693801A1 patent drawing

AI summary

A connection circuit and a charging gun having the connection circuit. The connection circuit is used for connecting an external power source and an electrical device to form a charge-discharge loop. The connection circuit comprises a power supply circuit, a control circuit, and a relay. The power supply circuit is connected to the external power source, and is used for converting the voltage of the external power source into a low voltage by means of power frequency transformation. The control circuit is connected to the power supply circuit, is used for acquiring the low voltage from the power supply circuit, and is configured to generate a control signal. The relay comprises an input side and an output side, the output side is arranged on the charge-discharge loop, and the input side is connected to the external power source and the control circuit and is configured to drive the output side to turn off or turn on the charge-discharge loop according to the control signal.