Secondary Battery Case Structure for Pressure and Deformation Control

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Solution Overview

Problem

Secondary batteries face challenges in managing internal pressure and deformation due to the expansion of electrolyte, leading to potential structural issues and safety concerns.

Innovation Solution

A secondary battery design featuring a case with concave areas on its long side surfaces and maintained negative pressure to accommodate electrolyte injection, reducing deformation and providing a buffer structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the case is designed with a fixed rigid structure, then manufacturing simplicity is maintained, but the case cannot accommodate electrolyte expansion and deformation occurs

Engineering Contradiction:

Improvestructural integrityVSAvoidaccommodation of electrolyte expansion

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The case is divided into multiple regions including flat regions and concave regions. The concave regions are specifically designed to deform and accommodate electrolyte expansion, while flat regions maintain structural integrity. This segmentation allows different parts of the case to serve different functions during battery operation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The case is designed with dynamic characteristics through the inclusion of concave regions that can deform in response to internal pressure changes. These concave regions act as buffer zones that expand and contract with electrolyte volume changes, allowing the case to adapt dynamically rather than remaining completely rigid.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If the case is designed with concave areas to accommodate electrolyte expansion, then adaptability to electrolyte volume changes is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveaccommodation of electrolyte expansionVSAvoidcase structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Rather than making the entire case complex, only specific local regions are designed with concave geometries. The flat regions remain simple and easy to manufacture, while the concave regions are strategically placed to handle expansion. This localized approach to complexity minimizes overall manufacturing difficulty while achieving the required adaptability.

Inventive Principle:

Principle #3Local quality

3Stability of the object's composition

If negative pressure is maintained in the case, then deformation is reduced and structural integrity is improved, but the risk of improper sealing and potential leakage increases

Engineering Contradiction:

Improvestructural integrityVSAvoidsealing reliability

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The concave regions are pre-designed as buffer zones that can absorb expansion forces before they reach critical levels. By providing this preemptive cushioning space, the system reduces the magnitude of pressure fluctuations, thereby lowering the stress on seals and reducing the risk of leakage while maintaining negative pressure benefits.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Volume of moving object

If the case volume is reduced to minimize battery size, then space efficiency is improved, but insufficient space for electrolyte injection and expansion occurs

Engineering Contradiction:

Improvebattery sizeVSAvoidelectrolyte accommodation space

Core Design Contradiction:

Volume of moving objectVSQuantity of substance

Solution Approach 1:

The concave regions are nested within the overall case structure, effectively utilizing the available volume. These recessed areas create internal buffer zones without increasing the external dimensions of the battery. The flat and concave regions are arranged to maximize space utilization, allowing electrolyte expansion space to be embedded within the existing case volume.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 design effectively manages internal pressure, minimizing deformation and ensuring structural integrity while maintaining a secure space for electrolyte, enhancing safety and performance.

Implementation Method 1

the inside sealed by the case and the cap plate is in a negative pressure state

Methodology Applied

Scientific EffectNegative pressure: Pressure Drop

Data Source

PatentUS20250329906A1Secondary battery and method for manufacturing the same

Publication Date: 2025.10.23 SAMSUNG SDI CO LTD

AI summary

Embodiments relate to a secondary battery, in which a concave area is provided in a case, and a negative pressure is maintained to secure a space, into which an electrolyte is injected, and reduce deformation due to an internal pressure, and which has a buffer structure against the falling, and a method for manufacturing the same. The secondary battery includes an electrode assembly provided with a first electrode plate and a second electrode plate, a case which has an interior space therein and in which the electrode assembly is accommodated, and a cap plate configured to seal an opening of the case. The case has a concave area that is concave toward the interior space of the case in each of two long side surfaces facing each other, and the interior space sealed by the case and the cap plate is in a negative pressure state.