EV Junction Box Insulative Member for Short Circuit Prevention

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Solution Overview

Problem

Existing electrical junction boxes for electric vehicles face challenges in preventing short circuits between conductors and the case while maintaining shielding performance, leading to increased production costs and decreased assembly efficiency due to complex structures and reduced operation space.

Innovation Solution

The use of a resin molded insulative member attached to the inner wall of the case, which prevents short circuits without coating the conductors, reduces production costs, and maintains operation space, thereby enhancing assembly efficiency by regulating crimped terminal rotation and providing locking mechanisms to prevent resin block movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the conductors are coated with resin to prevent short circuit, then the short circuit prevention is improved, but the manufacturing complexity and production cost increase

Engineering Contradiction:
Improveshort circuit preventionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of coating the conductors with resin to prevent short circuits, the patent inverts the approach by attaching an insulative member to the inner wall surface of the case. This reverses the traditional insulation method and achieves the same protective function while simplifying the manufacturing process and reducing costs.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The insulative member acts as an intermediary element between the case and the conductors. Rather than directly coating the conductors, this intermediate insulative layer provides the necessary electrical isolation, simplifying the overall structure and reducing manufacturing complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the conductors are coated with resin to prevent short circuit, then the short circuit prevention is improved, but the production cost increases

Engineering Contradiction:
Improveshort circuit preventionVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent inverts the traditional insulation approach by moving the insulative member from the conductors to the case interior surface. This inversion eliminates the need for expensive conductor coating processes while maintaining effective short circuit prevention, thereby reducing production costs.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The insulative member attached to the case is a simple, cost-effective component that provides the necessary insulation function. This approach replaces expensive conductor coating processes with a more economical insulative element, reducing overall production costs while maintaining reliability.

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

3Ease of operation

If the insulative member is attached to the inner wall surface of the case, then the operation space is maintained, but the shielding performance must be preserved

Engineering Contradiction:
Improveoperation spaceVSAvoidshielding performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The insulative member is strategically attached to the inner wall surface of the case where it is needed for insulation, while leaving other areas of the case intact to maintain shielding performance. This localized approach ensures both adequate operation space and preserved electromagnetic shielding.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The solution employs composite construction by combining the insulative member material with the conductive case material. This composite approach allows the insulative member to provide electrical isolation while the metallic case maintains its shielding properties, achieving both objectives simultaneously.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2844527B1Electrical junction box
Publication Date: 2016.07.27 YAZAKI CORP
  • EP2844527B1 patent drawingFigure 1
  • EP2844527B1 patent drawingFigure 2
  • EP2844527B1 patent drawingFigure 3

AI summary

An electrical junction box for connecting a power supply and a load, includes a terminal block that holds a conductor to which a first electric wire and a second electric wire are commonly connected, wherein first electric wire is connected to the power supply and the second electric wire is connected to the load, a conductive case that accommodates the terminal block, and a resin insulative member that is attached along an inner wall surface of the case. Crimped terminals which are connected respectively to ends of the first and second electric wires are fastened to the conductor with fastening members.