Secondary Battery Heat Accumulation Portion for Welding Thermal Management

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Solution Overview

Problem

Existing secondary battery designs face issues with heat transfer during welding, leading to potential gasket rupture, reduced sealability, and erroneous activation of the current interrupt device due to excessive heat causing deformation and rattling of components.

Innovation Solution

Incorporating a heat accumulation portion with higher thermal conductivity than the rivet member, sandwiched between the rivet member and the holder member, to accumulate and dissipate heat generated during welding, thereby reducing heat transfer to the gasket and preventing deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If welding is performed to connect the reversing plate to the rivet member, then electrical connectivity is established, but excessive heat is transferred to the gasket causing rupture or deformation

Engineering Contradiction:

Improveelectrical connectivityVSAvoidheat transfer to gasket

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A heat accumulation portion made of aluminum or aluminum alloy is introduced as an intermediary component between the rivet member and the gasket. This heat accumulation portion has higher thermal conductivity than the rivet member, allowing it to absorb and dissipate welding heat before it reaches the gasket, thereby preventing gasket damage while maintaining electrical connectivity through the rivet member.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If heat is transferred to the gasket, then welding connection is achieved, but the gasket temperature exceeds the glass transition point causing rupture

Engineering Contradiction:

Improvewelding connectionVSAvoidgasket temperature

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

The heat accumulation portion serves as a thermal intermediary that intercepts and absorbs excess welding heat. With thermal conductivity of 237 W/(m·K) or higher, it rapidly absorbs heat during welding and dissipates it through conduction and convection, keeping the gasket temperature below its glass transition point and preventing rupture.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the thermal parameters of the system by introducing a component with specifically high thermal conductivity (aluminum or aluminum alloy with ≥237 W/(m·K)). This parameter change allows the heat accumulation portion to effectively absorb and redistribute welding heat, controlling the temperature distribution to protect the gasket while maintaining welding effectiveness.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If the gasket loses elasticity due to heat, then welding is completed, but components begin to rattle and vibrate

Engineering Contradiction:

Improvewelding completionVSAvoidgasket elasticity

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The heat accumulation portion acts as a thermal buffer that prevents excessive heat from reaching the gasket during welding. By absorbing and dissipating heat through its high thermal conductivity, it preserves the gasket's elasticity and mechanical properties, preventing component rattling and vibration while allowing welding to be completed successfully.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Power

If heat accumulates in the rivet member, then welding connection is formed, but the gasket sealability is reduced

Engineering Contradiction:

Improvewelding connection strengthVSAvoidgasket sealability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The heat accumulation portion serves as a thermal mediator with higher conductivity than the rivet member. It intercepts welding heat and redistributes it through conduction and convection, preventing heat accumulation in the rivet member that would otherwise transfer to and compromise the gasket's sealability, while still enabling strong welding connections.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution effectively maintains the sealability of the battery by preventing gasket rupture and reducing rattling, enhancing the reliability of the secondary battery by ensuring proper heat management and preventing erroneous activation of the current interrupt device.

Implementation Method 1

a heat accumulation portion that thermally contacts the rivet member and has a thermal conductivity equal to or greater than the thermal conductivity of the rivet member

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS10340502B2Secondary battery and manufacturing method of secondary battery

Publication Date: 2019.07.02 TOYOTA JIDOSHA KK

AI summary

A secondary battery includes a scaling body (25), a rivet member (30), a gasket (27) that contacts the rivet member (30) and is fixed between the sealing body (25) and the rivet member (30), a holder member (60), a reversing plate (40) that deforms when an internal pressure of the exterior body (10) rises, and a heat accumulation portion (70) that contacts the rivet member (30) and has a higher thermal conductivity than the rivet member (30). An outer peripheral edge (42) of the reversing plate (40) is connected by welding to the peripheral edge portion (36) of the rivet member (30), and the heat accumulation portion (70) is sandwiched between the opposing portion (33) of the rivet member (30) and the extending portion (61) of the holder member (60).