Electric Junction Box Cooling Structure for Relay Heat Dissipation

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Solution Overview

Problem

Existing electric junction boxes struggle with inefficient heat dissipation, particularly from electronic components like relays and fuses, which generate Joule heat during operation, leading to potential degradation and operational issues.

Innovation Solution

The electric junction box incorporates a pair of cooling members that absorb heat from the outer surface and dissipate it externally, with a conductive member sandwiched between them, enhancing heat transfer through mounting walls and using heat transfer paste to efficiently dissipate Joule heat generated by internal circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electronic components (relay, fuse) are operated, then electrical function is achieved, but Joule heat is generated causing poor heat dissipation

Engineering Contradiction:

Improveoperational reliabilityVSAvoidheat dissipation

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

A conductive member is introduced as an intermediary between the electronic component and the cooling members. This conductive member includes mounting walls that extend toward the cooling members, creating a thermal conduction path. The conductive member serves as a mediator to transfer heat from the electronic component to the cooling members, resolving the heat dissipation problem while maintaining electrical functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces conventional thermal management approaches with a direct thermal conduction system. Instead of using complex cooling mechanisms, the invention uses the conductive member with mounting walls to establish direct thermal contact with cooling members, substituting mechanical cooling complexity with a simpler conduction-based system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Temperature

If heat dissipation structures are added, then heat dissipation is improved, but device complexity increases

Engineering Contradiction:

Improveheat dissipationVSAvoidstructural complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The conductive member is designed to serve multiple functions simultaneously: it provides electrical connection through busbars, mechanical support for the electronic component, and thermal conduction path through mounting walls. This multi-functionality reduces the need for separate dedicated heat dissipation structures, thereby limiting the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the functions of electrical connection and heat dissipation into a single integrated structure. The conductive member combines the busbar for electrical connection with mounting walls for thermal conduction, merging previously separate functions into one component to avoid increasing overall structural complexity.

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 improves heat dissipation capabilities, preventing components from interfering with switching mechanisms and maintaining efficient operation over time, even under conditions of component failure or external forces.

Implementation Method 1

a first cooling member and a second cooling member that are capable of absorbing heat from an outer surface and dissipating heat to the outside

Methodology Applied

Scientific EffectHeat dissipation: Convection

Implementation Method 2

Joule heat, which is generated in an internal circuit of the electronic component, contact points between the electronic component and the busbars, and the busbars during energization

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 3

Joule heat, which is generated in an internal circuit of the electronic component, contact points between the electronic component and the busbars, and the busbars during energization, is easily absorbed by the first cooling member and the second cooling member through the mounting walls

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS12573822B2Electric junction box

Publication Date: 2026.03.10 YAZAKI CORP

AI summary

An electric junction box includes: a first cooling member and a second cooling member; and a conductive member disposed to be sandwiched between the first and second cooling members. The conductive member includes a housing portion, an electronic component disposed inside the housing portion, and busbars being provided on a first mounting wall and a second mounting wall, and the conductive member is disposed such that an outer surface of the first mounting wall faces the outer surface of the first cooling member and an outer surface of the second mounting wall faces the outer surface of the second cooling member. The electronic component includes a plurality of terminals, and a movable contact point, and the electronic component is configured in such a manner that the movable contact point is located at a position farther away from the side wall than the plurality of terminals in the electronic component.