Pouch Battery Case Surface Layer Engineering Plastic Insulation

Solution Overview

Problem

Pouch-type lithium secondary batteries face issues with short circuits and electrolyte leakage due to aluminum in the battery case, and existing fabrication methods are costly and complex.

Innovation Solution

A lithium secondary battery design featuring a surface layer of engineering plastic on a pouch-type battery case with lead terminals drawn out, eliminating the need for an aluminum layer and using a single-layer insulating material for the case, which prevents short circuits and electrolyte leakage while reducing production costs through a simpler fabrication method.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a pouch-type battery case made of aluminum laminate is used, then the battery can be manufactured with low cost and small weight, but short circuits occur due to aluminum conductivity and electrolyte leakage happens at heat-sealed interfaces

Engineering Contradiction:

Improveproduction costVSAvoidshort circuit prevention

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The battery case is segmented into two functional layers: an inner aluminum layer for sealing and structural integrity, and an outer insulating layer for electrical isolation. This segmentation allows each layer to perform its specific function optimally without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The battery case uses a composite structure combining aluminum material with insulating material (such as polymer coating or laminated insulating layer). This composite approach leverages the advantages of both materials: aluminum provides excellent sealability while the insulating layer prevents short circuits.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If a pouch-type battery case made of aluminum laminate is used, then the battery can be manufactured with low cost and small weight, but electrolyte leakage occurs at heat-sealed interfaces

Engineering Contradiction:

Improveproduction costVSAvoidsealability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The battery case uses a composite structure combining aluminum material with insulating material (such as polymer coating or laminated insulating layer). This composite approach leverages the advantages of both materials: aluminum provides excellent sealability while the insulating layer prevents short circuits.

Inventive Principle:

Principle #40Composite materials

3Reliability

If a multilayer battery case structure is used to prevent short circuits and leakage, then reliability improves, but manufacturing complexity and production cost increase

Engineering Contradiction:

Improveshort circuit preventionVSAvoidcase structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of making the entire battery case complex, the insulating properties are applied locally where needed - specifically on the outer surface or at critical sealing areas. This localized approach provides necessary electrical isolation without requiring complete structural redesign.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The battery case uses a composite structure combining aluminum material with insulating material (such as polymer coating or laminated insulating layer). This composite approach leverages the advantages of both materials: aluminum provides excellent sealability while the insulating layer prevents short circuits.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS11189871B2Lithium secondary battery and method of fabricating the same

Publication Date: 2021.11.30 LG ENERGY SOLUTION LTD

AI summary

Provided are a lithium secondary battery, which includes an electrode assembly, a battery case accommodating the electrode assembly, a surface layer comprising an engineering plastic located on the outer side of the battery case, and lead terminals connected with the electrode assembly and drawn out of the battery case, and a method of fabricating the same.