Electrochemical Transistor Current Limiting for Battery Hot Spots

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Solution Overview

Problem

Current battery systems face challenges in controlling current flow within individual cells, leading to potential runaway reactions and catastrophic failures due to hot spots and internal shorts, which necessitate costly and bulky thermal and electrical management systems.

Innovation Solution

The implementation of an array of electrochemical transistors (ECTs) as current limiters, which are integrated between the energy device and the current collector, allowing for localized control of current flow through passive or active means, thereby suppressing hot spots and managing current distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sophisticated thermal and electrical management systems are implemented at the battery pack level, then safety against thermal runaway is improved, but cost, mass, and volume of the battery system increase

Engineering Contradiction:
Improvesafety against thermal runawayVSAvoidcomplexity of thermal and electrical management systems
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention divides the battery system into discrete controllable units by placing individual current limiters at the cell level rather than using a centralized management system. Each current limiter independently controls current flow in its associated battery cell, segmenting the overall system control function into modular units that can operate autonomously

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The current limiters are configured to automatically limit current flow when hot spots or internal shorts are detected, performing protective action before thermal runaway can occur. This preliminary protective action eliminates the need for complex post-detection response systems

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If current flow within individual battery cells is not controlled, then manufacturing complexity is reduced, but hot spots and internal shorts can cause catastrophic failures

Engineering Contradiction:
Improvesimplicity of battery assemblyVSAvoidprotection against hot spots and internal shorts
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Each battery cell is equipped with its own current limiter that autonomously monitors and controls current flow without requiring external intervention. The system serves itself by having distributed intelligence at the cell level, where each unit independently protects itself from thermal runaway conditions

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The current limiter acts as an intermediary device between the battery cell and the load, inserting itself into the current path to actively control and limit current flow. This intermediary component provides localized protection without requiring complex pack-level management systems

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 reduces the risk of thermal runaway and extends battery life by controlling current flow, allowing for safer and more efficient energy storage and consumption.

Implementation Method 1

incorporation of electrochemical-gating (EC) in nanowire electronics

Methodology Applied
Scientific EffectElectrochemical gating: Electrochemiluminescence

Implementation Method 2

electrochemically gated zinc oxide nanowire field effect transistors

Methodology Applied
Scientific EffectField effect transistor operation: Conduction (electrical)

Implementation Method 3

a channel disposed between the drain and the source electrodes

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3633748B1Current control systems and methods
Publication Date: 2024.12.11 PALO ALTO RESEARCH CENTER INC
  • EP3633748B1 patent drawingFigure 1
  • EP3633748B1 patent drawingFigure 2
  • EP3633748B1 patent drawingFigure 3

AI summary

A system that includes an energy device having an active region configured to generate or consume electrical energy provided by an electrical current is discussed. A current limiter is disposed between the energy device and a current collector layer. The current limiter controls the current flow between the energy device and the current collector layer. A plurality of electrochemical transistors (ECTs) are arranged in an array such that each ECT in the array provides localized current control for the energy device. Each ECT includes a gate electrode, a drain electrode, a source electrode, and a channel disposed between the drain and the source electrodes. An electrolyte electrically couples the gate electrode to the channel such that an electrical signal at the gate electrode controls electrical conductivity of the channel. The current collector layer is a shared drain or source electrode for the ECTs.