Electrode Assembly Current Limiters for Thermal Runaway Prevention

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Solution Overview

Problem

Conventional two-dimensional lithium-based secondary batteries face risks of thermal runaway due to uncontrolled energy release during abuse or extreme conditions, with existing safety mechanisms exhibiting a lag in current limitation, failing to prevent such events effectively.

Innovation Solution

Incorporation of current limiters in three-dimensional electrode assemblies using resistive polymeric materials that change state to increase electrical resistance or detach upon temperature increase, independent of thermal lag, thereby limiting current flow and preventing thermal runaway.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If three-dimensional battery architecture is used, then capacity and energy density are increased, but risk of thermal runaway is heightened due to higher energy concentration

Engineering Contradiction:

Improvebattery capacityVSAvoidrisk of thermal runaway

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent applies segmentation by dividing the three-dimensional battery architecture into multiple smaller battery assemblies, with each assembly containing its own current limiters. This segmentation allows individual assemblies to be isolated and protected independently, preventing thermal runaway from propagating across the entire high-capacity battery system while maintaining the overall three-dimensional structure and high energy density.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements beforehand cushioning by pre-installing current limiters within the three-dimensional battery architecture that are positioned to provide immediate protection against thermal runaway. These current limiters serve as a cushioning safety mechanism that is already in place before any abuse or extreme conditions occur, ready to activate and prevent thermal runaway events that might otherwise be more likely in high-energy-density three-dimensional configurations.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If current limiters are added to battery assembly, then safety is improved, but device complexity increases

Engineering Contradiction:

ImprovesafetyVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies merging by integrating current limiters directly into existing battery assembly components such as current collectors or tabs, rather than adding them as separate, discrete elements. This merging approach incorporates the safety function into the existing structural framework, improving safety without significantly increasing overall device complexity or requiring additional assembly steps.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent implements universality by designing current limiters that can be integrated into multiple different locations and configurations within the battery assembly (current collectors, tabs, separators). This multi-functional approach allows the same current limiter technology to serve various safety roles throughout the battery system, improving overall safety without requiring different types of components for different locations, thereby avoiding complexity multiplication.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution provides immediate current limitation and enhanced safety by preventing thermal runaway in three-dimensional batteries, even under abusive conditions, thus improving battery safety and reliability.

Implementation Method 1

the adhesive layer is configured to at least partially melt at or above the transition temperature to increase an electrical resistance between the electrode busbar and the electrode current collectors

Methodology Applied

Scientific EffectPhase change: Phase Change

Implementation Method 2

Methodology Applied

Scientific EffectTemperature-dependent resistance: Thermo-resistive Effect

Data Source

PatentUS20260058343A1Electrode assemblies for secondary batteries that include current limiters

Publication Date: 2026.02.26 ENOVIX CORP

AI summary

An electrode assembly includes unit cells stacked in a stacking direction, each including an electrode structure, a separator structure, and a counter-electrode structure. The electrode structure includes an electrode current collector and an electrode active material layer, the electrode structure extends in a longitudinal direction perpendicular to the stacking direction, an end portion of the electrode current collector extends past an outer surface of the electrode active material layer and the separator structure. The electrode assembly further includes an adhesive layer including a resistive polymeric material, and an electrode busbar attached to the end portions of the electrode current collectors through the adhesive layer. The adhesive layer is configured to adhere with the electrode busbar and the electrode current collectors below a transition temperature, and at least partially melt at or above the transition temperature to increase an electrical resistance between the electrode busbar and the electrode current collectors.