Magnetic Battery Pack Connection for Passive Fault Isolation

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Solution Overview

Problem

Current battery pack assembly with busbars is lengthy and costly, and there is a lack of effective systems for disconnecting and shunting failing accumulators while ensuring safety and continuity of operation, particularly in high-voltage battery packs.

Innovation Solution

A battery pack design utilizing magnetic locking and unlocking mechanisms with permanent magnets and ferromagnetic parts to enable passive disconnection of failing accumulators, allowing for safe isolation and shunting through gravity, and active control via electronic control systems to manage electrical connections and disconnections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional mechanical connection methods are used to assemble battery packs with busbars, then reliable electrical connection is achieved, but assembly time and cost increase

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidassembly speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent replaces traditional mechanical connection systems (screws, clips, welding) with a magnetic connection system. Permanent magnets in the busbar attract ferromagnetic parts on the accumulator terminals, creating reliable electrical connections through magnetic attraction forces. This substitution enables rapid, tool-free assembly while maintaining connection reliability through the inherent strength of magnetic attraction.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If magnetic locking mechanisms are added to enable passive disconnection of failing accumulators, then safety and continuity of operation are improved, but device complexity increases

Engineering Contradiction:

Improvesafety and continuity of operationVSAvoidconnection mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The magnetic connection mechanism provides self-service safety functionality. When an accumulator fails and heats up, the permanent magnet loses its magnetic properties above the Curie temperature, causing automatic disconnection of the failing cell from the busbar. This passive, self-actuating mechanism eliminates the need for complex active disconnection systems while improving safety and continuity of operation.

Inventive Principle:

Principle #25Self-service

3Strength

If permanent magnets are used for magnetic locking, then connection strength is improved, but loss of magnetic properties at high temperature causes disconnection

Engineering Contradiction:

Improveconnection strengthVSAvoidconnection stability at high temperature

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent converts the harmful effect of high temperature (which normally causes thermal runaway and safety issues) into a beneficial automatic disconnection mechanism. When an accumulator fails and its temperature exceeds the Curie point of the permanent magnet, the magnet loses its magnetic properties, causing passive disconnection of the failing cell. This transforms a potential safety hazard into a protective feature that isolates failing cells while maintaining strong connections during normal operation.

Inventive Principle:

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

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 reduces assembly time and cost, ensures safe and continuous operation by passively disconnecting failing accumulators, and allows for on-demand control of the battery pack, preventing thermal propagation and maintaining electrical continuity.

Implementation Method 1

the magnetic attraction force of the permanent magnet of the output terminal on the closure plate of a first busbar, in the closed magnetic circuit configuration, ensures the mechanical and electrical connection between the output terminal and the first busbar

Methodology Applied

Scientific EffectMagnetic attraction: Magnetism

Implementation Method 2

the permanent magnet of the output terminal heats up and at least to a temperature from which it loses its magnetic properties, to the point of mechanical disconnection between the output terminal and the first busbar

Methodology Applied

Scientific EffectCurie temperature effect: Curie Point (ferromagnetic)

Implementation Method 3

which causes the accumulator to drop through gravity

Methodology Applied

Scientific EffectGravity: Gravitation

Data Source

PatentUS11114730B2Accumulator battery pack, comprising devices for passive magnetic between accumulators and busbars, and, where appropriate, passive shunt of one or more accumulators in case of failure of these ones

Publication Date: 2021.09.07 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

AI summary

A battery pack wherein each battery is mechanically and electrically connected by a magnetic device to a busbar. In case of failure of any accumulator, it is disconnected completely passively because its failure generates an inactivation of the magnetic device. The disconnection causes the gravity drop of the accumulator and the possibly completely passive implementation of an accumulator shunt.