Battery Pack Recycling via Thermal Decomposition

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Solution Overview

Problem

Current methods for recycling battery packs require dismantling and natural discharge or forced discharge, posing safety risks and prolonging the recycling process due to the handling of high-voltage components.

Innovation Solution

A method and apparatus that roast battery packs in a charged state, thermally decomposing resin parts and insulating materials to disrupt the battery pack's function, allowing for safe and efficient recycling without dismantling, using a roasting device that controls temperature to prevent metal oxidation and allow for the recovery of valuable metals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If battery packs are dismantled for recycling, then valuable metals can be recovered, but workers must handle high-voltage components requiring insulating protectors and more time

Engineering Contradiction:

Improverecovery of valuable metalsVSAvoidhandling of high-voltage components

Core Design Contradiction:

Loss of substanceVSEase of operation

Solution Approach 1:

The battery pack is roasted in advance to discharge the battery assembly and decompose resin parts before dismantling. This preliminary thermal treatment eliminates the high-voltage hazard, allowing workers to dismantle and recover valuable metals without requiring insulating protectors or special safety procedures

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The roasting process changes the physical and chemical parameters of the battery pack components. The battery assembly is heated to discharge its charge, and resin parts are thermally decomposed into carbonized materials. These parameter changes transform the battery pack from a hazardous high-voltage state to a safe state suitable for dismantling

Inventive Principle:

Principle #35Parameter changes

2Reliability

If battery packs are kept in storage for natural discharge, then safety is improved, but the recycling process is prolonged

Engineering Contradiction:

Improvesafety during recyclingVSAvoidrecycling process duration

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Instead of passive natural discharge over an extended period, the patent applies active preliminary thermal discharge through roasting. The battery assembly is heated to a temperature that causes rapid discharge and decomposition of resin parts, achieving the safety objective in a much shorter time frame

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The roasting process utilizes phase transitions and thermal decomposition. The resin parts transition from their original state to carbonized materials through heating, and the battery assembly undergoes thermal discharge. These phase changes and chemical transformations achieve rapid discharge without requiring long storage periods

Inventive Principle:

Principle #36Phase transitions

3Productivity

If roasting temperature is increased to decompose resin parts, then recycling efficiency is improved, but metal parts may oxidize or melt

Engineering Contradiction:

Improverecycling efficiencyVSAvoidintegrity of metal parts

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The patent optimizes the roasting temperature parameter to fall within a specific range that balances two competing requirements: high enough to decompose resin parts effectively but low enough to prevent metal oxidation and melting. This controlled parameter change achieves both decomposition and metal preservation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The battery pack contains composite materials including resin parts, metal parts, and battery assembly components. The roasting process selectively treats different material components based on their thermal properties, decomposing organic resin parts while preserving inorganic metal parts through controlled temperature management

Inventive Principle:

Principle #40Composite materials

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

Enables safe and efficient recycling of battery packs in a shorter time by avoiding the need for dismantling and natural discharge, allowing for the separation and recovery of valuable metals while maintaining metal parts in their original forms.

Implementation Method 1

roasting the battery pack that houses the battery assembly that is in a charged condition, as it is... thermally decomposing resin parts and insulating materials

Methodology Applied

Scientific EffectThermal decomposition: Pyrolysis

Implementation Method 2

using a roasting device that controls temperature to prevent metal oxidation

Methodology Applied

Scientific EffectOxidation prevention: Oxidation

Data Source

PatentUS8696785B2Method and apparatus for recycling battery pack

Publication Date: 2014.04.15 TOYOTA JIDOSHA KK

AI summary

A method for recycling a battery pack includes steps of: roasting the battery pack that houses a battery assembly that is in a charged condition, as it is, dismantling the roasted battery pack and separating the battery pack into unit cells and parts other than the unit cells, comminuting the unit cells obtained by separation, washing and screening the comminuted cells, dehydrating a slurry below a sieve after screening and recovering metals used for positive and negative electrodes, and recovering metal containing nickel by magnetically separating metal remaining on the sieve after screening, using a magnet.