Wiring Board with Low-Rigidity Insulating Layer for Battery Volume Changes

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Solution Overview

Problem

Wiring boards with embedded electronic components, such as secondary batteries, face damage due to volume changes during use, leading to defects as existing resin materials do not adequately absorb these changes without causing stress to the components.

Innovation Solution

A wiring board design featuring a first and third insulating layer made of high-rigidity resins, with a low-rigidity second insulating layer to accommodate volume changes of the secondary battery, and via connections to maintain electrical contact while minimizing damage from these changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a resin layer is used to embed the secondary battery, then the battery is fixed and protected, but the battery may be damaged due to volume changes during use

Engineering Contradiction:

Improveprotection of secondary batteryVSAvoiddamage-free operation

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent changes the rigidity parameter of the resin layer by selecting specific materials with appropriate rigidity values. The resin layer is designed to have rigidity within a specific range (0.1-10 MPa) to balance protection and flexibility, allowing it to accommodate battery volume changes while maintaining structural support.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material structures including multiple resin layers with different rigidities, and combinations of resin materials such as silicone resin, polyimide resin, and epoxy resin. This composite approach allows the wiring board to provide both rigid support and flexible accommodation for battery expansion.

Inventive Principle:

Principle #40Composite materials

2Strength

If a high-rigidity resin is used for the insulating layer, then structural integrity is maintained, but volume changes of the secondary battery cause damage to the battery

Engineering Contradiction:

Improvestructural integrityVSAvoidstress on secondary battery

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating different resin layers with different rigidities at different locations. The layer directly contacting the battery has low rigidity to accommodate volume changes, while outer layers have higher rigidity for structural support. This gradient structure locally adapts to the battery's expansion needs while maintaining overall structural integrity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements beforehand cushioning by designing the low-rigidity resin layer to preemptively absorb and cushion the volume changes that occur during battery operation. This preventive measure avoids stress concentration and potential damage before it occurs, allowing the battery to expand and contract freely within the cushioned space.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If the same resin material is used for all insulating layers, then manufacturing is simplified, but the ability to absorb volume changes is reduced

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidvolume change absorption

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by assigning different resin materials to different layers based on their specific functions. The inner layer uses soft resin for volume change absorption, while outer layers use harder resins for structural support and insulation. This differentiated material selection optimizes both manufacturing feasibility and functional performance.

Inventive Principle:

Principle #3Local quality

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

The low-rigidity second insulating layer absorbs volume changes of the secondary battery, reducing the risk of damage and maintaining the integrity of the wiring board, while the high-rigidity layers provide structural support and stable electrical connections.

Implementation Method 1

a rigidity of the second insulating layer is lower than those of the first and third insulating layers

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS9224684B2Wiring board and method of manufacturing wiring board

Publication Date: 2015.12.29 SHINKO ELECTRIC IND CO LTD

AI summary

There is provided a wiring board. The wiring board includes: a first insulating layer; a secondary battery on one surface of the first insulating layer; a second insulating layer formed on the secondary battery; a third insulating layer covering the second insulating layer; a first wiring layer on one surface of the third insulating layer; and a via electrically connecting the first wiring layer to an electrode of the secondary battery. A rigidity of the second insulating layer is lower than those of the first and third insulating layers.