Battery Pack Breaker Assembly for Weld Vibration Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional breakers experience displacement and generation of cutting scrap during ultrasonic welding, leading to potential contact failure between movable and fixed contacts due to vibration, which can result in interposed resin scraps.

Innovation Solution

A breaker design featuring a movable piece with an elastic portion and a thermally-actuated element, housed within a resin case with a second resin case that embeds the movable piece and has a recessed structure to prevent displacement and cutting scrap, ensuring accurate positioning and secure contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ultrasonic welding is used to join case main body and lid member, then productivity and manufacturing efficiency are improved, but the movable piece is displaced and cutting scrap is generated due to vibration

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidpositioning accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The movable piece is preliminarily fixed to the case main body using adhesive before ultrasonic welding. This preliminary action prevents the movable piece from being displaced by welding vibrations, thereby maintaining positioning accuracy while still allowing ultrasonic welding to be used for joining the case components.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The adhesive layer acts as a cushioning medium between the movable piece and the welding process. It absorbs and dampens the vibrations generated during ultrasonic welding, protecting the movable piece from displacement and preventing cutting scrap generation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Productivity

If ultrasonic welding is performed on the case, then manufacturing speed is improved, but resin cutting scrap is generated due to vibration interference

Engineering Contradiction:

Improvewelding speedVSAvoidcutting scrap

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The adhesive is applied to the movable piece before the ultrasonic welding process begins. This preliminary bonding prevents the movable piece from interfering with the case main body during welding, thereby preventing resin cutting scrap from being generated while maintaining high welding speed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The adhesive, which could be seen as an additional step slowing production, actually prevents the harmful effect of cutting scrap. By converting the potential harm of vibration-induced interference into a beneficial protective function, the adhesive enables fast ultrasonic welding without generating scrap.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If the movable piece is not fixed during welding, then ease of assembly is improved, but contact reliability deteriorates due to displacement

Engineering Contradiction:

Improveassembly simplicityVSAvoidcontact reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The adhesive provides preliminary fixation of the movable piece to the case main body before final assembly completion. This ensures the movable piece maintains its correct position and prevents contact reliability issues, while still allowing for relatively simple assembly processes.

Inventive Principle:

Principle #10Preliminary action

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 suppresses displacement and cutting scrap during welding, maintaining accurate contact between movable and fixed contacts, thereby preventing contact failure and ensuring reliable operation.

Implementation Method 1

a thermally-actuated element which is deformed in response to temperature changes so as to shift the movable piece from a conductive state in which the movable contact contacts with the fixed contact to a cut-off state in which the movable contact is separated from the fixed contact

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

a movable piece, which has an elastic portion being elastically deformable and a movable contact in one end portion of the elastic portion, and which is for pressing the movable contact against the fixed contact to contact therewith

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 3

a case main body and a lid member are ultrasonically welded to form a case

Methodology Applied

Scientific EffectUltrasonic welding: Ultrasonic Vibration

Data Source

PatentUS20250006443A1Breaker, Safety circuit and Secondary battery pack

Publication Date: 2025.01.02 BOURNS KK

AI summary

The breaker has a fixed contact; a movable piece having an elastic portion and a movable contact; a thermally-actuated element deformed in response to temperature changes so as to shift the movable piece from a conductive state in which the movable contact contacts with the fixed contact to a cut-off state in which the movable contact is separated from the fixed contact; a case main body having an accommodation recess for the fixed contact, movable piece and thermally-actuated element; and a lid member fixed to the case main body to cover the accommodation recess. The lid member has an embedding portion in which a part of the movable piece is embedded and a first recess which is recessed in a thickness direction of the lid member. The case main body has a first protruding portion fitted into the first recess.