High Voltage Junction Box Board Stacking Leakage Prevention

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

High-voltage electrical junction boxes in vehicles face issues with leakage currents due to potential differences between high and low-voltage circuits, increased complexity and cost from numerous bus bars and wires, and reliability concerns from loose fastening of bolts, leading to bulkiness and inefficient use of in-vehicle space.

Innovation Solution

A high-voltage electrical junction box design featuring an insulating box body with a board hosting bus bars and printed patterns on either side, connected by press-fit connection pieces that reduce component count, prevent leakage currents, and enhance assembly efficiency, while mechanical and electrical connections ensure reliability and miniaturization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If high voltage and low voltage circuits are arranged on the same plane inside the junction box, then the routing becomes simpler, but leakage current occurs due to potential difference

Engineering Contradiction:
Improvecircuit routing complexityVSAvoidleakage current
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent transitions from planar arrangement to three-dimensional arrangement by stacking high voltage and low voltage circuits on opposite surfaces of an insulating board. This dimensional separation eliminates leakage current paths while maintaining routing simplicity through the board's integrated through-holes and connection pieces.

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

Solution Approach 2:

An insulating board is introduced as an intermediary element between high voltage and low voltage circuits. The board provides both electrical isolation to prevent leakage current and structural integration to simplify routing through its through-holes and connection pieces.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If numerous bus bars and electric wires are used to connect various electric components, then the circuit connectivity is improved, but the assembly work becomes more cumbersome and cost increases

Engineering Contradiction:
Improvecircuit connectivityVSAvoidassembly work
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Multiple separate connection elements (bus bars and electric wires) are merged into a single integrated insulating board structure. The board simultaneously provides mechanical support, electrical isolation, and circuit connectivity through its through-holes and connection pieces, reducing component count and simplifying assembly.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The insulating board serves multiple functions simultaneously: it acts as a mechanical support structure, an electrical insulator, a routing channel through through-holes, and a mounting platform for electric components. This multi-functionality reduces the need for separate specialized components.

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

3Device complexity

If various electrical components, bus bars and electric wires are continuously arranged on a single plane, then the circuit layout is simplified, but the junction box becomes bulky and in-vehicle space cannot be used effectively

Engineering Contradiction:
Improvecircuit layoutVSAvoidjunction box volume
Core Design Contradiction:
Device complexityVSVolume of moving object

Solution Approach 1:

The patent utilizes the third dimension by stacking high voltage and low voltage circuits on opposite surfaces of the insulating board. This vertical arrangement reduces the horizontal footprint and overall volume of the junction box while maintaining simplified circuit layout through the board's integrated structure.

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

4Strength

If bolt fastening is used to connect various electrical junction boxes to bus bars and electric wires, then the connection is secure, but the fastening function can be lost due to screw loosening and reliability decreases

Engineering Contradiction:
Improveconnection strengthVSAvoidcircuit connection reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent replaces the mechanical bolt fastening system with an integrated press-fit connection system. Connection pieces are inserted through through-holes and secured by elastic deformation or interference fit, eliminating loose fastening issues while maintaining strong electrical and mechanical connections.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The connection function is merged into the insulating board structure itself through integrated through-holes and connection pieces. This eliminates separate fastening components and creates a unified, reliable connection system that prevents loosening.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2696456B8High voltage electrical junction box
Publication Date: 2016.11.02 FURUKAWA ELECTRIC CO LTD

AI summary

To provide a high-voltage electrical junction box that can prevent an occurrence of a leakage current and improve reliability of connection, that can reduce cost by achieving an easy assembly operation, and further make an effective use of an in-vehicle space by realizing miniaturization. A high-voltage electrical junction box 1 includes an insulating box body 13 and a circuit structure 14 accommodated in the box body 13. The circuit structure 14 includes a group of bus bars 22 of a high-voltage system disposed on an upper surface 21a of the board 21, a group of printed patterns 41 of a low-voltage system formed on a lower surface 21b of the board 21, a through hole 23 formed to penetrate through each bus bar, the board 21 and each printed pattern, and a connecting piece 24 that is inserted into the through hole and connected to each bus bar, the board 21 and each printed pattern.