Electrical Junction Box Thermal Management

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Solution Overview

Problem

Conventional electrical junction boxes do not effectively prevent condensation and freezing issues on relay contacts due to heat distribution and current supply variations among various electrical components, leading to potential malfunctions.

Innovation Solution

The electrical junction box design includes a casing with an inner and outer wall structure, featuring cutouts and ventilation holes to facilitate heat dissipation, and positions electrical components at the outer end or corners for efficient heat release, reducing temperature differences and condensation risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If electrical components are housed in a conventional electrical junction box with uniform structure, then the box can accommodate various electrical components, but temperature distribution becomes uneven leading to condensation and freezing on relay contacts

Engineering Contradiction:
Improveability to accommodate various electrical componentsVSAvoidtemperature distribution uniformity
Core Design Contradiction:
Adaptability or versatilityVSTemperature

Solution Approach 1:

The patent applies local quality by creating a temperature-controlled zone around the relay using thermal insulation material. This insulating barrier is selectively placed only where needed (around the relay and terminal) rather than uniformly throughout the entire junction box, allowing different regions to have different thermal characteristics. This resolves the contradiction by maintaining adaptability for various components while creating a localized thermally stable environment for the relay contacts.

Inventive Principle:
Principle #3Local quality

2Reliability

If heat dissipation structures are added to the electrical junction box, then condensation and freezing can be prevented, but the device complexity increases

Engineering Contradiction:
Improveprevention of condensation and freezing on contactsVSAvoidstructural complexity of heat dissipation system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs the self-service principle by utilizing the relay's own coil as a heating element to prevent condensation. The coil, which already consumes electrical power for its operation, is positioned in proximity to the terminal and contact area. When energized, the coil generates heat that naturally warms the surrounding region, preventing moisture condensation and freezing without requiring additional heating components or complex thermal management systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent introduces thermal insulation material as an intermediary substance between the relay/terminal and the surrounding environment. This insulating material acts as a thermal mediator that traps and retains heat generated by the coil, directing it toward the contact area while blocking heat loss to the external environment. This simple intermediary element effectively prevents condensation and freezing without adding complex active heating or cooling systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively reduces the likelihood of condensation and freezing on relay contacts, ensuring reliable operation by maintaining optimal temperatures and preventing malfunctions in low-temperature environments.

Implementation Method 1

heat generated by the coil in the electrical component case

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

moisture in the electrical component case can be actively condensed on the metal plate by heat generated by the coil

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

the heat can be easily released from the electrical component case to the outside of the casing compared to a double-layered structure including the inner wall and the outer wall

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2779337B1Electrical junction box
Publication Date: 2017.06.28 AUTONETWORKS TECH LTD
  • EP2779337B1 patent drawingFigure 1
  • EP2779337B1 patent drawingFigure 2
  • EP2779337B1 patent drawingFigure 3

AI summary

An electrical junction box 10 includes a casing 11 and a relay 20 housed in the casing 11. The relay 20 is located at an outer end in the casing 11. The relay 20 includes an electrical component case 20a and a terminal 20b. The terminal 20b is attached through the electrical component case 20a and includes a fixed contact FC and a movable contact MC located in the electrical component case 20.