Battery Case Groove Structure for Electrode Expansion Pressure

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Solution Overview

Problem

Existing secondary batteries face issues with electrode expansion during charging and discharging, leading to pressure on the case, which can cause cracks and potential short circuits due to differences in electrode sizes and material volume changes.

Innovation Solution

Incorporating a groove region on the inner peripheral surface of the battery case to accommodate electrode expansion, with specific dimensions and orientations to reduce pressure on the electrodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the case is made rigid to maintain structural integrity, then strength is improved, but electrode expansion causes pressure and potential cracks

Engineering Contradiction:

Improvecase strengthVSAvoidelectrode integrity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The case is segmented into a rigid outer structure and a flexible inner layer, allowing the flexible layer to accommodate electrode expansion while the outer structure maintains overall strength and integrity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A flexible inner layer or coating is applied to the case interior, enabling the case to flex and accommodate electrode volume changes during charging and discharging, preventing cracks while maintaining structural integrity

Inventive Principle:

Principle #30Flexible shells and thin films

2Reliability

If the case is made flexible to accommodate electrode expansion, then electrode integrity is improved, but case strength decreases

Engineering Contradiction:

Improveelectrode integrityVSAvoidcase strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The case is divided into functional zones: a rigid outer shell for strength and a flexible inner layer for accommodation, with each layer optimized for its specific function

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The case uses composite construction combining rigid materials (for strength) and flexible materials (for expansion accommodation), creating a multi-layer structure that achieves both requirements simultaneously

Inventive Principle:

Principle #40Composite materials

3Volume of moving object

If the electrode assembly is tightly fitted in the case to maximize space utilization, then volume efficiency is improved, but pressure on electrodes increases during expansion

Engineering Contradiction:

Improvespace utilizationVSAvoidelectrode pressure

Core Design Contradiction:

Volume of moving objectVSStress or pressure

Solution Approach 1:

The flexible inner layer acts as a pre-designed cushioning element that absorbs expansion pressure before it can be transmitted to the rigid case and electrode components, preventing damage while maintaining tight fitting

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Ease of manufacture

If the case structure is simplified to reduce manufacturing complexity, then ease of manufacture is improved, but ability to accommodate electrode expansion decreases

Engineering Contradiction:

Improvecase manufacturingVSAvoidexpansion accommodation

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

A flexible coating or thin film layer is applied to the case interior, adding expansion accommodation capability to a otherwise simple rigid case structure with minimal impact on manufacturing complexity

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

Inventive Principle:

Principle #40Composite materials

Data Source

PatentEP4712181A1Secondary battery

Publication Date: 2026.03.18 SAMSUNG SDI CO LTD

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AI summary

A secondary battery, including an electrode assembly including a first electrode, a second electrode, and a separator therebetween, a case including a bottom portion, a side wall portion connected to the bottom portion, and an opening portion facing the bottom portion, the case accommodating the electrode assembly, and a cap assembly coupled to one end of the side wall portion of the case to seal the opening portion, wherein the case includes a groove region formed on an inner peripheral surface of the side wall portion.