Injection-Molded Relay Packaging for Liquid Ingress Isolation

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Solution Overview

Problem

Conventional packaging of electromagnetic relays in liquid-cooled systems fails to prevent liquid infiltration, leading to poor contact and operation delays due to liquid resistance, affecting the normal functioning of the relay.

Innovation Solution

A specially packaged relay with an injection molded body that wraps the electromagnetic relay, exposing only external terminals and vent holes on opposite sides, and incorporating heat dissipation grooves and chamfers to enhance insulation and heat dissipation, while using a material with different thermal properties for the cover.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional packaging is used for electromagnetic relay, then manufacturing is simple, but liquid infiltration occurs leading to poor contact and operation delay

Engineering Contradiction:

Improverelay operation reliabilityVSAvoidpackaging structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The packaging structure is segmented into multiple functional zones: a sealed cavity for the electromagnetic relay, a vent hole for pressure equalization, and an injection molded body with heat dissipation grooves. This segmentation allows the relay to be isolated from liquid while maintaining operational functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The injection molded body acts as an intermediary barrier between the electromagnetic relay and the liquid environment. It provides both sealing protection and heat dissipation functions, mediating between the relay's operational needs and the liquid cooling system.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If more glue is used around cover and base, then liquid infiltration is prevented, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvesealing performanceVSAvoidmanufacturing simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The sealing function and heat dissipation function are merged into a single integrated injection molded body. This eliminates the need for separate sealing materials like glue, simplifying the manufacturing process while maintaining both sealing performance and thermal management.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The injection molded body uses composite material properties to simultaneously achieve sealing (through precise molding) and heat dissipation (through integrated grooves). This replaces the need for multiple materials like glue and metal heat sinks.

Inventive Principle:

Principle #40Composite materials

3Volume of moving object

If terminal heat capacity is limited, then relay structure remains compact, but liquid infiltration risk increases

Engineering Contradiction:

Improverelay sizeVSAvoidliquid infiltration resistance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

Heat dissipation is moved from a two-dimensional terminal interface to a three-dimensional structure with injection molded grooves. This dimensional expansion provides increased heat dissipation surface area without increasing the relay's footprint, while the molded structure inherently prevents liquid infiltration.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

Ensures stable operation of the electromagnetic relay in a liquid environment for extended periods by preventing liquid ingress and improving heat dissipation, thus maintaining reliable performance and reducing thermal stress impacts.

Implementation Method 1

The injection molded body is injection molded outside the electromagnetic relay and wraps the electromagnetic relay therein... effectively blocks the external liquid from flowing into the electromagnetic relay

Methodology Applied

Scientific EffectPhysical barrier:

Implementation Method 2

a plurality of heat dissipation grooves is respectively and circumferentially arranged on outer side surfaces of the injection molded body

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

The heat generated by electronic components inside the device is directly and efficiently transferred to the liquid

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS12597574B2Specially packaged relay and packaging method thereof

Publication Date: 2026.04.07 XIAMEN HONGFA ELECTROACOUSTIC CO LTD

AI summary

The present disclosure discloses a specially packaged relay and a packaging method thereof. The relay includes an electromagnetic relay and an injection molded body. The injection molded body is injection molded outside the electromagnetic relay and wraps the electromagnetic relay therein. A plurality of conventional terminals of the electromagnetic relay are respectively exposed, or the conventional terminals of the electromagnetic relay are respectively located within the injection molded body, and each of the conventional terminals of the electromagnetic relay is connected with an external terminal that is exposed. The electromagnetic relay of the present disclosure is completely wrapped and sealed by the injection molded body, and is completely isolated from external liquid, which can effectively prevent the external liquid from flowing into the electromagnetic relay and ensure the electromagnetic relay to work stably for a long time in a liquid environment.