What Role Do Laboratory Hydraulic Presses Play In Solid-State Battery Assembly? Forge High-Performance Cells

Laboratory hydraulic presses, paired with titanium pillars and PEEK molds, are the fundamental tools for converting loose powder materials into functional all-solid-state battery cells. By applying immense pressure—up to 375 MPa—these systems eliminate microscopic voids between particles, densifying the electrolyte and electrode layers to establish the continuous ionic and electronic pathways required for battery operation.

The Core Insight In solid-state battery assembly, the primary failure mode is often poor contact between solid particles. The combination of high hydraulic pressure and specialized mold materials solves this by mechanically forcing materials into a unified, dense state, thereby minimizing interface resistance and enabling stable cycling performance.

Overcoming the Solid-Solid Interface Challenge

To understand the equipment, you must understand the problem: unlike liquid electrolytes that naturally wet electrodes, solid electrolytes have "hard" interfaces.

Eliminating Microscopic Voids

The primary function of the laboratory hydraulic press is densification. Loose powders contain air gaps that block ion flow.

By applying cold-pressing pressures reaching 375 MPa, the press forces particles together, effectively eliminating these voids. This mechanical interlocking is the only way to ensure the battery functions as a cohesive unit rather than a collection of isolated particles.

Establishing Transmission Networks

A battery requires two continuous networks to function: one for ions and one for electrons.

The high-pressure environment created by the press ensures that electrolyte and electrode layers are compacted sufficiently to form these continuous transmission networks. Without this extreme densification, the cell would suffer from high internal impedance and fail to hold a charge.

The Critical Role of Specialized Components

The press provides the force, but the mold components determine the quality and viability of the final cell.

PEEK Molds: Insulation and Integrity

Polyether ether ketone (PEEK) is the material of choice for the mold body due to its unique combination of mechanical strength and electrical properties.

Electrical Insulation: PEEK is an insulator, which prevents short circuits during the pressing process. It allows for in-situ electrochemical testing, meaning you can test the battery cell while it is still inside the mold, eliminating the risk of damaging the fragile pellet during removal.

Chemical Stability: PEEK is chemically resistant, preventing reactions with aggressive battery chemistries. This ensures the sample remains pure and free from contamination by metal impurities that could degrade performance.

Titanium Alloy Pillars: Force Transmission

While the mold holds the shape, the pillars act as the pistons that transfer the hydraulic force to the powder.

High-strength titanium alloy is required to withstand the immense pressures (up to 375 MPa) without deforming. These pillars ensure that the force is applied uniformly across the surface of the cell, which is critical for creating a flat, consistent electrolyte layer.

Operational Precision and Trade-offs

Achieving a high-performing cell is not just about applying maximum pressure; it is about process control.

The Importance of Pre-forming

The assembly process often involves a multi-step pressure strategy. For example, solid electrolyte powders (like Li3PS4) are often pre-formed at lower pressures, such as 120 MPa.

This step creates a mechanically strong, flat substrate before the electrode materials are added. Skipping this pre-forming step can lead to uneven layers and structural defects in the final stack.

Managing Interface Resistance

The ultimate goal of using this specific hardware suite is to reduce interface resistance.

By ensuring close contact between the solid-state electrolyte and the electrode materials, the press reduces the barrier to ion movement. This directly translates to improved cycling performance and longevity of the battery cell.

The Trade-off: In-Situ vs. Ex-Situ

Using PEEK molds allows for testing without moving the sample (in-situ), which preserves the interface quality.

However, relying solely on in-situ testing molds can limit throughput compared to mass-producing pellets for external testing. You must balance the need for interface integrity against the need for high-volume sample processing.

Making the Right Choice for Your Goal

The equipment you prioritize should align with the specific stage of your battery development.

If your primary focus is fundamental material research: Prioritize PEEK molds with in-situ testing capabilities to eliminate handling errors and accurately measure intrinsic material properties without interface damage.
If your primary focus is maximizing cell density: Ensure your hydraulic press system is rated for at least 375 MPa and utilizes high-strength titanium pillars to achieve the highest possible compaction without equipment deformation.

Success in solid-state battery assembly relies not just on the chemistry, but on the mechanical precision used to forge those chemicals into a unified solid mass.

Summary Table:

Component	Material/Spec	Primary Function in Battery Assembly
Hydraulic Press	Up to 375 MPa	Eliminates voids, densifies layers, and establishes ionic pathways.
PEEK Mold	Polyether ether ketone	Provides electrical insulation for in-situ testing and chemical stability.
Pillars	High-strength Titanium	Transmits immense force uniformly to prevent electrode deformation.
Process Step	Pre-forming (~120 MPa)	Creates a flat, stable electrolyte substrate before adding electrodes.

Maximize Your Battery Research Precision with KINTEK

At KINTEK, we specialize in comprehensive laboratory pressing solutions designed to meet the rigorous demands of all-solid-state battery development. From manual and automatic presses to heated and glovebox-compatible models, our equipment ensures the extreme densification required to eliminate interface resistance.

Whether you need cold/warm isostatic presses or specialized PEEK and titanium tooling for in-situ testing, our solutions provide the mechanical precision your research deserves.

Ready to elevate your cell assembly process?
Contact KINTEK today to find your ideal pressing solution

References

Jaehee Park, Ying Shirley Meng. Realizing Low-Pressure Operation of All-Solid-State Lithium–Sulfur Batteries Enabled by Carbon-Coated Current Collectors. DOI: 10.26434/chemrxiv-2025-shdxv

This article is also based on technical information from Kintek Press Knowledge Base .