Flexible Battery Fixing Member Prevents Electrode Displacement

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Solution Overview

Problem

Existing flexible batteries fail to maintain stability and prevent short circuits when repeatedly bent due to relative displacements of electrode layers and separators, leading to increased stress and potential damage during flexure.

Innovation Solution

A flexible secondary battery design featuring a fixing member between end portions of the electrode stack assembly, which includes a pouch, electrode layers, and a separator, with connection tabs extending perpendicularly to secure the assembly and a protection layer with greater bending stiffness than the electrode layers, ensuring uniform stress distribution and maintaining electrochemical reaction arrangement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If flexible battery is designed without fixing members, then ease of manufacture is improved, but stability during repeated bending deteriorates due to relative displacements of electrode layers

Engineering Contradiction:

Improveease of manufactureVSAvoidstability during repeated bending

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The battery structure is segmented into distinct functional regions: flexible electrode layers for electrochemical reactions, and rigid fixing member regions for structural stability. The fixing members are positioned at specific locations (end portions and center) to create localized rigid zones that prevent displacement while allowing the majority of the battery to remain flexible.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different parts of the battery have different mechanical properties: the electrode layers are designed to be flexible to enable bending, while the fixing member regions are designed to be rigid to prevent relative displacement. This local differentiation of mechanical properties allows the battery to simultaneously achieve flexibility and stability during repeated bending.

Inventive Principle:

Principle #3Local quality

2Reliability

If fixing members are added to prevent relative displacement, then stability during bending is improved, but device complexity increases

Engineering Contradiction:

Improvestability during bendingVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The fixing members are extracted as separate, independent components from the electrode layers. This allows the fixing members to be positioned and secured independently, simplifying the overall manufacturing process while effectively preventing relative displacement between electrode layers during bending.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The fixing members act as intermediary elements between the electrode layers, serving as mediators that prevent direct contact and potential short circuits between positive and negative electrodes while maintaining the flexibility of the overall battery structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If electrode layers are allowed to displace relative to each other, then flexibility is improved, but short circuit risk increases

Engineering Contradiction:

ImproveflexibilityVSAvoidshort circuit risk

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The fixing members serve as intermediary elements positioned between the electrode layers, preventing direct contact between positive and negative electrodes that could cause short circuits. These intermediaries maintain safe spacing while allowing the battery to flex and bend.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The fixing members provide beforehand cushioning by pre-establishing fixed reference points that prevent excessive displacement of electrode layers. This prior structural support cushions against the harmful effect of short circuits that could occur during repeated bending operations.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP2882025B1Flexible secondary battery

Publication Date: 2018.05.16 SAMSUNG SDI CO LTD

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Figure 2(A)~2(C)
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AI summary

A flexible secondary battery includes an electrode stack assembly including a first electrode layer, a second electrode layer, and a separator between the first and second electrode layers; wherein the electrode stack assembly has a first end portion and a second end portion located opposite to the first end portion; and a fixing member fixing the first electrode layer, the separator, and the second electrode layer together; wherein the electrode stack assembly includes a fixing member region in which the fixing member is formed, the fixing member region being located between the first and second end portions of the electrode stack assembly in a first direction, and wherein the first electrode layer, the separator, and the second electrode layer are flexible at both sides of the fixing member.