Bipolar Conductive Polymer Films for Low-Resistance Battery Stacks

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Solution Overview

Problem

Monopolar electrochemical device designs require extensive connecting materials, leading to high internal resistance and increased costs due to the need for corrosion-resistant materials, especially in aqueous battery applications.

Innovation Solution

The use of bipolar structures with conductive polymer films that are non-porous and impermeable, composed of conductive particles and non-conductive polymers, reduces the need for extensive connecting materials and inhibits corrosion, thereby lowering costs and enhancing energy density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If monopolar designs are used with extensive connecting materials, then device assembly is simplified, but internal resistance increases and material costs increase

Engineering Contradiction:

Improvedevice assemblyVSAvoidinternal resistance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent merges the current collector and separator functions into a single bipolar structure. The bipolar current collector serves both as an electrical conductor and as a separator between cells, eliminating the need for separate connecting materials and reducing overall device complexity while maintaining low internal resistance.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bipolar current collector performs multiple functions simultaneously: it collects current, separates adjacent cells, provides mechanical support, and prevents direct contact between electrolytes of adjacent cells. This multi-functionality reduces the number of components needed and simplifies device assembly.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If corrosion-resistant materials are used for connecting materials, then reliability against corrosion is improved, but material costs significantly increase

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidmaterial cost

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts the connecting materials from the device architecture by using a bipolar design where adjacent cells are connected through shared current collectors. This eliminates the need for separate connecting materials that would require corrosion resistance, thereby reducing material costs while maintaining reliability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The porous bipolar current collector acts as an intermediary structure that prevents direct contact between electrolytes of adjacent cells while still allowing electrical connection. This intermediary function eliminates the need for additional corrosion-resistant barrier materials.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If bipolar structures with conductive polymer films are used, then through-plane resistance decreases and energy density increases, but manufacturing complexity increases

Engineering Contradiction:

Improvethrough-plane resistanceVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses composite materials consisting of conductive polymers combined with conductive fillers (such as carbon black, graphite, or metal particles) to create the bipolar current collector. This composite structure provides both the required electrical conductivity and mechanical properties, simplifying manufacturing compared to using pure metals while achieving low through-plane resistance.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameters by using conductive polymers with adjustable conductivity through composition control and processing conditions. This allows optimization of through-plane resistance while maintaining ease of manufacture through solution casting or extrusion processes.

Inventive Principle:

Principle #35Parameter changes

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

Bipolar structures with conductive polymer films achieve lower through-plane resistance, reduce material costs, and enhance energy density by minimizing the use of expensive connecting materials and preventing corrosion.

Implementation Method 1

the polymer matrix has sufficient polymer content to form an impermeable layer to ion transport within the film

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 2

the conductive particles have sufficient conductive particle content to provide electrical conduction pathways

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS12334589B2Bipolar structures for use with electrochemical devices, and associated systems and methods

Publication Date: 2025.06.17 BENAN ENERGY

AI summary

Disclosed herein are polymer conductive films for use with electrochemical devices. An exemplary electrochemical device can include an anode, a cathode, and a bipolar structure disposed between the anode and cathode. The bipolar structure includes a film having a plurality of conductive particles and a plurality of non-conductive polymers, wherein the polymers are integrated with the particles such that the film is non-porous and substantially compositionally homogeneous along a length and/or thickness of the film.