Battery Pack Casing Locking Mechanism for Thin Structural Strength

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Solution Overview

Problem

Conventional battery packs with small thickness face challenges in achieving adequate structural strength against external impacts and coupling strength due to reduced thickness and material limitations, particularly with the use of ultrasonic welding for assembly.

Innovation Solution

The battery pack employs locking members on the upper cover and corresponding locking grooves on the case body for mechanical coupling, allowing the use of high-strength materials like stainless steel for the upper cover and plastic for the case body, eliminating the need for ultrasonic welding and enabling further thickness reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If ultrasonic welding method is used to couple the upper cover and case body, then assembly is achieved, but welding strength is reduced when thickness is decreased to 0.3 to 0.35 mm

Engineering Contradiction:

Improveassembly methodVSAvoidwelding strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent replaces the ultrasonic welding method with a mechanical coupling system consisting of locking protrusions on the upper cover that engage with locking grooves on the case body. This substitution eliminates the dependency on welding strength for thin materials while maintaining secure assembly through mechanical interlocking.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The coupling mechanism is divided into distinct functional elements: locking protrusions on the upper cover, locking grooves on the case body, and a pressing member for engagement. This segmentation allows each component to be optimized independently for its specific function while working together to achieve secure coupling.

Inventive Principle:

Principle #1Segmentation

2Length of moving object

If thickness of case body and upper cover is decreased to reduce battery pack thickness, then miniaturization is achieved, but structural strength against external impacts is reduced

Engineering Contradiction:

ImprovethicknessVSAvoidstructural strength

Core Design Contradiction:

Length of moving objectVSStrength

Solution Approach 1:

The patent employs different materials for different components: the upper cover is made of high-strength stainless steel while the case body uses plastic material. This composite approach allows the thin upper cover to maintain adequate structural strength against external impacts while achieving overall miniaturization of the battery pack.

Inventive Principle:

Principle #40Composite materials

3Length of moving object

If thickness of case body and upper cover is decreased, then battery pack thickness is reduced, but coupling strength between upper cover and case body is reduced

Engineering Contradiction:

ImprovethicknessVSAvoidcoupling strength

Core Design Contradiction:

Length of moving objectVSStrength

Solution Approach 1:

The locking protrusions are designed with curved surfaces that fit into the locking grooves, creating a mechanical interlock that maintains coupling strength even when the overall thickness of the components is reduced to 0.3 to 0.35 mm.

Inventive Principle:

Principle #14Spheroidality (Curvature)

4Strength

If high-strength material such as stainless steel is used for upper cover, then structural strength is improved, but manufacturing cost increases

Engineering Contradiction:

Improvestructural strengthVSAvoidmanufacturing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent applies high-strength stainless steel material specifically to the upper cover where structural strength against external impacts is most critical, while the case body uses cost-effective plastic material. This localized application of high-strength material optimizes the balance between performance and cost.

Inventive Principle:

Principle #3Local quality

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

This mechanical coupling method enhances the battery pack's structural strength against external impacts and improves coupling strength, enabling the use of high-strength materials while reducing thickness to 0.1 to 0.2 mm, without the limitations of ultrasonic welding.

Implementation Method 1

a plurality of elastic locking members are formed at edges of the upper case

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

The ultrasonic welding method is a method of welding two surfaces to be attached using frictional heat generated by high-frequency vibrations, for example, 20,000 Hz

Methodology Applied

Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 3

welding two surfaces to be attached using frictional heat generated by high-frequency vibrations

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS7479758B2Battery pack casing with lock type connector

Publication Date: 2009.01.20 LG ENERGY SOLUTION LTD

AI summary

Disclosed herein is a battery pack having locking members formed at an upper cover and locking grooves formed at a case body such that the locking members can be engaged in the corresponding locking grooves. The assembly of the battery pack is accomplished by a mechanical coupling method, not by an ultrasonic welding method, and the battery pack is manufactured with a high-strength material. Consequently, the battery pack can be manufactured while the thickness of the battery pack is further decreased.