Composite Electrode Fabrication via Adhesive-Free Pressure Bonding
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Solution Overview
Problem
The existing methods for fabricating composite electrodes for double layer capacitors rely on adhesives, which increase costs, add processing steps, and can lead to increased internal resistance and reduced energy storage efficiency due to adhesive degradation and penetration into the active electrode material's pores.
Innovation Solution
A composite electrode is fabricated using a conductive current collector sandwiched between two film layers of active electrode material, processed in a high-pressure, high-temperature nip to create a pressure bond without adhesives, with surface roughening or activation treatments to enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesives are used to bond active electrode material to current collector, then bonding strength is improved, but internal resistance increases and energy storage efficiency decreases
Solution Approach 1:
The invention removes the adhesive layer from the electrode structure, directly bonding the active electrode material to the current collector through thermal and pressure treatment. This extraction of the harmful adhesive component eliminates the source of internal resistance and energy loss while maintaining structural integrity through direct contact and sintering processes.
Solution Approach 2:
The invention introduces a conductive paste or slurry as an intermediary material between the active electrode material and current collector. This intermediary provides both electrical conductivity and mechanical bonding, replacing the insulating adhesive while maintaining electrical contact and reducing internal resistance.
2Ease of manufacture
If adhesives are used to fabricate composite electrodes, then ease of manufacture is improved, but manufacturing cost increases
Solution Approach 1:
The invention eliminates the adhesive material from the manufacturing process, removing both the material cost and the associated application steps. The bonding is achieved through thermal and pressure treatment of the direct interface between active material and current collector, reducing overall manufacturing complexity and material expenses.
Solution Approach 2:
The invention enables the electrode components to bond to each other through self-sintering or direct thermal bonding without requiring external adhesive materials. The active electrode material and current collector serve their own bonding function through controlled heating and pressing, eliminating the need for separate adhesive application and curing processes.
3Ease of operation
If adhesives are used in electrode fabrication, then ease of operation is improved, but charge and discharge rates decrease
Solution Approach 1:
The invention removes the adhesive layer that impedes ion transport and electron flow, creating a direct conductive pathway between the active electrode material and current collector. This extraction eliminates the resistance barrier that slows charge and discharge rates while the simplified structure maintains ease of handling during assembly.
Solution Approach 2:
The invention creates a composite structure where the active electrode material directly contacts the current collector, forming an integrated conductive network. This composite interface without adhesive layers enables faster electron and ion transport, improving charge and discharge rates while maintaining structural coherence through controlled bonding.
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 approach reduces internal resistance, minimizes material costs, and maintains high energy storage efficiency by eliminating adhesive-related issues, resulting in improved charge and discharge rates and extended capacitor lifespan.
Implementation Method 1
processed in a high-pressure, high-temperature nip to create a pressure bond without adhesives
Implementation Method 2
with surface roughening or activation treatments to enhance adhesion
Data Source
AI summary
Composite electrodes are constructed with pressure-bonding techniques instead of an adhesive. A current collector is made from aluminum foil roughed on both surfaces. The surfaces of the collector can be treated to enhance adhesion to the surfaces. Layers of film that includes active electrode material, such as activated carbon, are fabricated and pressure-bonded to the current collector using a calender with heated rollers. The resulting composite sheet is then processed to shape electrodes, which can be used in electrical energy storage devices, including double layer capacitors.