The first stage of battery production is to synthesise a slurry containing the active materials for the anode and cathode. This stage often begins with sintering the raw materials in a furnace, of which we can supply a variety of types:

• Tube Furnaces– horizontal, vertical, rotary, multi-zone
• High Pressure Furnaces – high vacuum, rocking, multi-zone, varying temperatures and capacities

Subsequently, the active material will be milled into smaller particles and then mixed into a slurry. We support a wide range of mills and mixers, depending on the material specifications, such as desired particle size and whether it is wet or dry.

• Ball Mills –planetary, rotary, vibration and shaker ball mills, varying capacities, includes varied sizes and quantities of milling jars
• Vacuum Mixers –planetary, varying capacities, water chiller

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After the active material has been processes and the slurry has been mixed, there are supplementary steps that can be taken to examine the slurry quality and to ensure consistency between batches:

• ‍Filtration –removes any lumps and impurities in the slurry, available with different meshes to remove particles of specific sizes, models with magnetic de-ironing filtration systems
• Viscosity tester – includes four testing spindles, and an immersion probe for temperature testing

Once the electrode slurry is prepared, it must be coated onto metal foils. To understand the importance of coating in the battery research and production process, watch this video from our Energy Research expert, Geoff Handley-Harrison.

In general, there are two main ways that slurry coatings can be applied to electrodes:

• Flatbed Film Coaters – generally for lower throughput, most include vacuum chucks to securely hold the foil onto the coater, available with heating elements (top, bottom, top and bottom, UV), different coating heads available (see below)

• Roll-to-Roll Coaters – appropriate for high-throughput production, can perform continuous and intermittent coating, various sizes and coating heads available, available with heating elements

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To achieve a thin and uniform electrode coating, it is essential to choose the most appropriate coating head, based on your slurry characteristics, such as viscosity. Certain coater can employ a combination of these techniques. Some examples include:

• Doctor Blade – placed on the surface of the substrate, with the blade positioned at a precise height above the surface. Slurry is poured in front of the blade, which then moves steadily across the substrate surface at a controlled speed for a set distance, leaving behind a uniform film of slurry, as thin as 10µm.

• Slot Die – coating material is channeled onto the substrate through a narrow slot, as the coating head passes over the substrate at a controlled speed for a set distance. The slot width can by altered precisely by metal shims, and the coating head does not come into contact with the substrate surface. A slot die can be used to print patterns of electrodes, as the slurry flow can be precisely controlled, and coatings can be as thin as 5µm.

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• Reverse Comma –the substrate moves opposite to a stationary comma bar, applying a uniform layer of coating. The thickness can be precisely controlled and intermittent coatings can be achieved to print patterns.
• Micro Gravure –a gravure roll is partially submerged in the coating liquid, as this rotates as the substrates passes over it. A flexible doctor blade with remove excess slurry, allowing coatings as thin as 2-3µm.

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Coaters can be fed manually, but for many applications an automated syringe pump is a valuable piece of equipment to ensure that coaters are fed a precise amount of coating material at a specific rate.

• Available in varying volume capacities and pump rates, with additional features such as heating

For coaters that don’t incorporate heating or drying elements, slurry solvents should be removed in a separate machine:

• Vacuum Ovens – varying capacities, available with multi-zone heating

Calendaring compresses the coated electrode foils to ensure a desired coating thickness and density. This stage is crucial for maximising cell energy density, and it also improves the structural integrity of the electrode by making it more resistant to delamination.

Some coating machines will incorporate calendaring processes, particularly in the larger roll-to-roll coaters. Separate rolling presses are also available:

• Cold Rolling Presses – controlled pressures, varying materials widths, glovebox compatible models, models available capable of pressure up to 100T
• Hot Rolling Presses – varying materials widths, varying max temps up to 250°C, variable speeds, models available capable of pressure up to 30T

At this stage, film lamination can also be conducted. The coated electrode foil can be laminated between sheets of ion exchange membrane or separator film, creating a singular unit. This stage can be incorporated into the coating machines, or can be purchased as individual lamination presses.

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Once a coated foil has been obtained, it should be cut into appropriately sized and shaped electrodes, based on the type of cell that you’re making. When cutting electrodes from the foil, it is best practice to maximise usage of the foil area, by cutting shapes as close as possible to each other. We can provide slitting machines to cut electrodes for different forms of battery research.

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Coin cell electrodes are cut with disc cutters:

• Hand-held disc cutter can be used for small volumes of cells – available with multiple die sizes, up to 32mm. If you require use of a glovebox, operation of hand-held cutters can be more difficult, so automation is preferrable
• Larger volumes will necessitate use of precision cutters or high-throughput pneumatic cutters – up to 24mm dies available with customisation, can cut up to 8 electrodes simultaneously

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Pouch cell electrodes can be cut using similar equipment to high-throughput pneumatic coin cells – some machines can be modified to cut both coin and pouch cells, by using different dies. Equipment for cutting pouch cell electrodes come in varying sizes and with different levels of automation:

• Die cutters – can be manual, semi-automatic or fully-automatic
• Standard sizes are 56 x 43mm and 58 x 45mm, but larger sizes up to 380 x 380 are also available
• Automated roll-to-roll cutting machines are available for high-throughput applications

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Cylinder and prismatic cell electrodes are fabricated with semi-automatic or roll-to-roll slitting machines, many of which can be multi-functional for creating pouch cell electrodes with specific dies.

• Available in multiple sizes for varying sheet lengths

After cutting the foil into electrodes, the next important step is to compile the anode, cathode and separator in the correct order within the cell casing. Whether this is done manually or automatically will depend on the cell type. Where the process can be automated, we can provide the appropriate machinery.

Coin cells components are manually stacked in the order: positive case, cathode, separator, anode, spacer, spring, negative case. The electrolyte should be injected before the coin cell is closed.

‍Pouch cells can be stacked by hand, however a semi-automatic or automatic stacking machine can speed up the process and improve the stacking precision.

• These can perform regular Z-type stacking and piece-by-piece sequence stacking for solid-state battery applications. They are available in bench-top or floor-standing models.

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‍Cylinder and prismatic cells require the anode, separator and cathode to be wound together into a jelly roll, before being inserted into the casing.

• This stage can be completed with a manual winding machine, however semi-automatic or fully-automatic winding machines can streamline this process.

After arranging the cell components, cylindrical, pouch and prismatic cells will have their current tabs welded on, using an ultrasonic welder. These tabs ensure that the cells can be connected into an external circuit. We can supply a wide range of welders for this purpose, some of which can be used in a glovebox.

Sealing is the final stage to achieve a completed cell, and involves securing all components inside their casing with an electrolyte.

Before sealing, the electrolyte must be injected into the cell. This can be done with standard digital bottle dispensers, or it can be automated with a vacuum electrolyte injector (varying sizes and can have programmable settings). Some sealing machines can incorporate electrolyte injection. 

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• Coin cells - after injecting the electrolyte, the cell is sealed shut with a hydraulic, pneumatic or electric crimper. Pneumatic and electric crimpers can aid in preventing contamination of a glovebox.

• Pouch cells – pouch cell cases can be purchased as either standard pre-formed pouches, made from aluminium laminated film, or can be formed as part of the manufacturing process using a case forming machine. Bespoke dies are available.
  

• We can supply compact heat sealers, 3-in-1 sealers (pre-sealing, vacuum sealing, electrolyte diffusion and degassing) or 4-in-1 sealers (side sealing, purging, vacuum standing and vacuum sealing – can remove oxygen and moisture to allow solid-state cells to form a better Solid Electrolyte Interphase (SEI) layer)

• Cylinder cells – this stage begins with the case being grooved (semi-automated desktop groovers can be supplied), the bottom on the case is deep welded, the electrolyte injected, and then the top is sealed using manual or automated crimpers, which can be pneumatic or hydraulic.
• Prismatic cells – once the electrolyte is injected, the casing is sealed with a laser welder. 

Once cell production is complete and the battery is functional, we can provide equipment for you to test the performance and durability of your cell. 

Battery analysers automatically cycle the cells, recording and logging performance data. They are modular, allowing up to 20 analysers to be connected via an Ethernet cable connector to one computer (up to 160 individual cells).

• Equipment can have up to 8 programmable channels for battery analysis, and is available with varying configurations. Many also come with a laptop with pre-installed software for analysis, including evaluation of cell capacity and lifecycle.

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For pouch and prismatic cells, an SEI formation machine can be used prior to battery testing and analysis. They are designed to provide an even pressure load and temperature environment to achieve a more efficient and high-quality Solid Electrolyte Interphase within the battery. 

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For more specialised research, alternative cell cases can be supplied that allow a variety of testing processes:

• Split test cells: allows rapid assembly and disassembly of cells to easily test different electrodes without needing to crimp the cells.

• ‍Three-electrode split test cells can be used to compare electrodes to a reference cell‍
• Split test cells for lithium air battery research can be used to control airflow pressure to simulate and test lithium-air batteries‍
• Split test cells with quartz windows can be used for in-situ Raman analysis

• Split test cells with beryllium window allow for in-situ XRD and XAS 

• Kapton window coin cell cases: allow in-situ X-ray analysis of battery material to explore phase variations during charging and discharging. Available with single-side window or two-sided windows. 

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To ensure the durability of a cell, test chambers can be provided to test the response of a cell to various external stimuli.

• Temperature and humidity test chambers – variety of machines available to test temperatures from -70°C – 200°C, and humidities from 20% – 98% relative humidity. Some options are encased with explosion-proof boxes.
• Crushing and nail penetration – single- and dual-purpose machines available, with maximum 200KN force available for crushing, and nail speeds up to 130 mm/s. Some options are encased with explosion-proof boxes.
• Short-circuiting – tests the response of cells to short-circuiting under controlled temperatures and pressures, or using high currents. 

Can pilot line equipment be scaled up?

Many types of equipment in a battery pilot line can be scaled for longer production runs, such as higher slurry quantities, larger electrode foils, or different sizes of cutting dies. However, some equipment is more difficult to scale; for example, moving from coin cell to pouch cell production.

Overall, it is important to understand future goals for scaling, as many machines will have a maximum capacity. This is something that should be discussed with our battery experts, to ensure your long-term targets can be met in the most efficient way possible.

What battery chemistries are supported?

These pilot lines are not limited by cell chemistry; therefore they support universal research chemistries such as lithium, sodium and potassium. Solid state battery research can also be accommodated.

For a full overview of the chemistries that can be supported, view our supply partners’ websites: LTS Laboratories, NEI Corporation and MTI Corporation. 

Can I use the equipment in a glovebox or dry room?

The majority of pilot line equipment can be used within a glovebox or dry room, however it is crucial that this requirement is highlighted during initial consultations, as certain customisations may need to be made to accommodate this. 

We can supply a variety of gloveboxes, with up to 5 chambers, and features such as gas purification and atmosphere control. Pre-fabricated dry rooms can also be supplied, with a variety of sizes from 6m² to 45 m², and additional features including dehumidification systems and water chillers. 

What are the lead times for pilot line equipment?

Lead times will vary, and can be dependent on several factors, including whether the item is stocked, whether is it bespoke, and whether any modifications need to be made. All lead times will be transparently indicated in initial quotations.

Do you offer help with installation?

Our standard pieces of equipment require minimal assembly, so customers can install onsite directly using our O&M manuals. If you experience difficulties with equipment setup or operations, our UK based product experts will be able to help. We can also facilitate video support meetings with technical engineers.

For larger and more complex pilot line systems, we can arrange for engineers to assist with onsite installation, setup, and equipment training. These requirements will be discussed with our dedicated project team during the enquiry process.

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