Secondary Battery Molded Part for Structural Stability

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Solution Overview

Problem

Conventional pouch-shaped batteries face issues with low mechanical strength and sealing force, leading to separation of sheathing members during charge and discharge, and require additional members for increased stability, which complicates assembly and increases weight and size.

Innovation Solution

A secondary battery with a molded part of predetermined thickness formed outside the sheathing member, enhancing mechanical strength and sealing force, allowing for stable stacking without additional members and simplifying assembly, while also providing coolant flow channels and coupling features for efficient heat dissipation and mounting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a pouch-shaped battery with a two-unit sheathing member is used, then the battery can be manufactured with small weight and high integration, but the mechanical strength is low and the sealing force is insufficient causing separation during charge and discharge

Engineering Contradiction:
Improvebattery weightVSAvoidmechanical strength and sealing force
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The sheathing member is divided into a body portion and a sealing portion, with the molded part selectively formed only at the sealing portion. This segmentation allows the battery to maintain lightweight characteristics while reinforcing only the critical sealing areas that require enhanced mechanical strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The molded part is formed locally at the sealing portion rather than uniformly across the entire sheathing member. This local reinforcement provides enhanced mechanical strength and sealing force exactly where needed during charge and discharge cycles, without unnecessarily increasing the overall weight of the battery.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If additional members are mounted to increase mechanical strength and stability, then the structural stability improves, but the assembly process becomes complicated and the battery pack size and weight increase

Engineering Contradiction:
Improvestructural stabilityVSAvoidassembly process complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The molded part integrates multiple functions into a single component: it reinforces mechanical strength, enhances sealing force, provides structural stability for stacking, and forms coolant flow channels. This merging eliminates the need for separate additional members, simplifying the assembly process while maintaining structural stability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The molded part serves multiple purposes simultaneously: structural reinforcement, sealing enhancement, stacking stability, and thermal management through coolant channels. This multi-functionality replaces what would otherwise require multiple separate components, reducing assembly complexity and battery pack size.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Weight of moving object

If the sheathing member is made thinner to reduce weight, then the weight to capacity ratio improves, but the mechanical strength and sealing force decrease leading to separation during operation

Engineering Contradiction:
Improvebattery weightVSAvoidsealing reliability during charge and discharge
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The sheathing member is segmented into regions with different thickness requirements: the body portion remains thin for weight reduction, while the sealing portion receives a molded part for localized reinforcement. This ensures sealing reliability during charge and discharge without compromising the overall lightweight design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The molded part provides localized thickness enhancement at the sealing portion only, maintaining the thin-profile advantage in the battery body while ensuring sufficient mechanical strength and sealing force where required for reliable operation during charge and discharge cycles.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP1889309B1Secondary battery of novel structure and battery pack having the same
Publication Date: 2021.05.05 LG ENERGY SOLUTION LTD
  • EP1889309B1 patent drawingFigure 1
  • EP1889309B1 patent drawingFigure 2
  • EP1889309B1 patent drawingFigure 3

AI summary

Disclosed herein are a secondary battery including an electrode assembly for charging and discharging mounted in a sheathing member including a metal layer and a resin layer, wherein the secondary battery further includes a secondary battery having a molding part of a predetermined thickness at least partially formed at the outside of a sheathing member, preferably, at a sealing region of the sheathing member, and a medium- or large-sized battery pack including the same. The molding part is formed at the outside of the sheathing member of the secondary battery. Consequently, the secondary battery according to the present invention has high mechanical strength, and therefore, it is possible to construct a battery pack without using addition members, such as cartridges. When the molding part is formed at the sealing region, which is weak, the molding part increases the mechanical strength and the sealing force of the secondary battery. Consequently, a battery pack including the secondary batteries as unit cells can be manufactured generally in a compact structure and with relatively small weight, and the assembly process of the battery pack is greatly simplified. The battery pack according to the present invention has high structural stability. Consequently, the battery pack can be preferably used as a power source for electric vehicles, hybrid electric vehicles, electric motorcycles, and electric bicycles.