Efficient Use of Budget and Time when commissioning a Battery Research Pilot Line
This Insight is taken from a talk originally given by Geoffrey Handley-Harrison at Advanced Materials Show, Battery Spotlight session in June 2023.
"Thank you for taking the time to visit us today and for listening to our talk which I hope will enlighten you and give you some hints and tips when looking at your requirements for battery research. As many of you are aware, PI-KEM have been in this business for over 30 years, supporting numerous educational and research establishments across the UK and Europe. For most of that time we have been working very closely with MTI Corporation in the US as their UK and European distributor for equipment and materials. As you can appreciate, during that time a lot of developments and new technology has been worked on. Things don’t ever standstill, which is why we like to keep abreast of new developments, so we are able to support you wherever you are on the journey.
Deciding on a Battery Research line and the numerous pieces of equipment you will require seems daunting at face value, and when you start looking at all the various options that are available to you it starts to get progressively worse in terms of trying to figure out the actual specifications for each piece of equipment. If you try and google search the various options available each one will take you off into another direction with different companies offering different variations at different levels and before you know it you could have spent weeks trying to establish the starting point but don’t appear any further forward.
Now, PI-KEM have been working on Battery Research lines for years, and within that time have worked on small size coin cell research lines in a glovebox, small pouch cell lines, cylinder cell lines and even larger pre-production size lines shipped on several pallets, and we’ve learnt a lot during that time and have a good understanding of what works and what doesn’t and the type of equipment that genuinely saves you a lot of time and effort to make your projects more efficient. We’ve also worked with different variations of technology, Lithium being the more dominant one at the moment, but we also work on Zinc Nickel and have a live project at the minute with that, and more recently Sodium technology and our Sodium Chips which can save a lot of time for our researchers in the lab by using ready prepared discs instead of having to manufacture them in house. So, rather than starting right back at the beginning and trying to reinvent the wheel, PI-KEM can draw on our knowledge and expertise and you can benefit from the number of different enquiries we’ve worked on around Europe to find the best solutions for you.
So, we’ve spoken so far about all the different options available and technologies that are out there and how complicated it can get very quickly if we’re not careful. However, for any battery line that we are considering, it can be broken down into 6 essential stages: Mixing; Coating; Calendaring; Slitting; Stacking and Sealing. We have created a step by step guide on “How to Create a Battery Cell” which walks you through all these different steps and provides initial suggestions depending on the type of battery you are manufacturing and the scale that you producing. What is important to recognise is that this is a guide and unfortunately as with a lot of things there is not “one size fits all”, so again depending on your own individual requirements there could be variations depending on your specifications.
If we start off with mixing – this starts with material synthesis quite often using a furnace to sinter the raw active materials for the cathode and anode. There are many options available for the furnace which we can provide and these will depend on your unique requirements. The simplest type of furnace used is the tube furnace, and these can be either single zone or multi zone, and have options for working under vacuum, high pressure, sliding tube, rocking as well as ultrasonic spray pyrolysis designed for the synthesis of core shell nanoparticles. There are also a range of options available to support your requirements in terms of different processing tubes, atmospheric analysers and control units to ensure a stable environment. Each application will require a slightly different approach and this is where our experience and expertise can assist you in quickly establishing the correct equipment needed to achieve your desired results. Following material synthesis the active material is then milled and again we have numerous options on offer starting with the simple ball mill with various size jars and different configurations, vacuum mixers with different specifications and sizes up to high shear mixing and more specialist applications.
After this we move onto the coating stage. In its most basic form a simple doctor blade can be used to apply a layer of active material across the foil. What we normally see in the smaller lab scale set ups is the use of a compact tape caster which has a vacuum chuck to ensure the foil is kept flat during the application stage, and a variable speed film applicator which automatically passes over the foil to apply the active material. Numerous options are available on these for both the base unit, which can include options for heating on the base, from the top, both of these and also ultra violet if required and there are several size options available within this range. We also offer different size options for the doctor blades in terms of widths, adjustable and also hybrid film applicators that can do tape coating for thicker films and slot die coating for thin films which is an excellent tool for lab scale film coating via a slurry for battery electrodes, perovskite solar film and fuel cell membranes. For facilities that are working on larger scale manufacture, we have options for roll to roll coaters using standard doctor blade, reverse comma blade, micro-gravure coating, slot die coating and some combinations of these, and on the larger machines this can also combine with either cold or hot calendaring or film lamination. If we’re not using one of the larger combined machines there are suitable separate calendars available starting with the 4 inch width electric calendars, the roll to roll compact option or the 20T pressure controlled rolling machine.
Upon completion of the electrodes, we move onto the slitting stage which varies depending on whether were manufacturing coin cells, pouch cells or cylinder cells.
Coin cells use disc cutters which in their most simplest form use a hand held disc cutter for small volume applications. These are simple to use for low volumes inside a glove box, however as we start to scale up we tend to find people move away from these as they are cumbersome to use especially inside a glove box whilst wearing protective gloves, and opt for a quicker more accurate precision cutter, or if even larger volumes are required there is a high throughput pneumatic cutter which will cut multiple electrodes within a glovebox. We find that most research applications are now using the 20XX sized coin cells for their applications and the majority of equipment is set up as standard for this size, although we have options available to support other sizes when required.
Pouch cells can use similar equipment as for high throughput coin cells but we also have options for pouch cells, starting with standard size offerings of 56 x 43mm and 58 x 45 mm electrode sizes which fit nicely into the standard 62 x 46mm pre formed pouch cells, but we also have the possibility to customise these right up to 380 x 380mm on the larger cutters. A common pitfall when increasing the size of the cell size are the added complexities associated with the increase in size and this is an example of where we work very closely with MTI and the research facility to establish the exact parameters and the desired outcome of the application to ensure that the complete equipment selection will meet the requirements at every stage and result in successful cell production. We’ve achieved this in the past by arranging a 3 way discussion between PI-KEM, the research facility and the technical experts at MTI who know precisely how each of their machines operate and if necessary have been able to customise equipment especially for the end user to provide a bespoke solution rather than a compromise. There are also automatic roll to sheet cutting machines available to support the higher volume end.
Cylinder cells will use either a semi-automatic slitting machine or for the larger applications a roll to roll slitter where we have several options available to meet the specific requirements of the facility.
After this stage, depending on the equipment options selected previously we may have a requirement for drying if this hasn’t already been completed, and this is normally performed in a vacuum oven, for which there are again different options for size and multiple heating zones.
Stacking is the next stage we move onto, which for coin cell is a fairly simple operation where the spacer, pre-cut anode, pre-cut spacer, pre-cut cathode, spacer and spring are assembled together with the electrolyte into the coin cell case. For pouch cells we can perform a similar process at this stage of stacking the pre-cut anodes, separator film and cathodes by hand. However, what we typically find are semi-automatic stacking machines that are able to perform this operation in a repeatable and precise manner to ensure continuity and increase throughput and even fully automatic versions to increase volumes even further. We also have the capability to support solid state batteries for those institutions that are specialising in this line of research. For cylinder cells this is the winding process where the anode, separator and cathode are wound together to form a cylinder and this can be performed using a manual winding machine, semi-automatic or a full roll to roll winder depending on the end user’s requirements. On both pouch cells and cylinder cells we also need to weld on the current tabs for which we use an ultrasonic welder, depending on the size of the stack for pouch cells, or to plan for future upsizing if that is within your scope, will depend on the type of ultrasonic welder that best meets your overall requirements.
Finally, sealing where we complete the battery unit, and for coin cells after filling with electrolyte we would use either a hydraulic crimper, or if we’re working in a glove box we would recommend either a pneumatic or electric driven crimper in order to prevent contamination of the glove box or a clean room. Pouch cells are a bit more complex as it involves several stages, the first one to seal the pouch cell case, which will either be performed using one of our standard size pouch cell cases, or a bespoke size manufactured using a pouch case forming machine with a bespoke die, in either case the process is the same. There are several options for sealing pouch cells and again, the selection will depend on the desired set up within the laboratory as to the final equipment selected. We have ranges starting with compact pouch cell sealers, 3-in-1 sealers which can perform the preliminary sealing of top and side before electrolyte injection, vacuum sealing after electrolyte injection and final vacuum standing for electrolyte diffusion and degassing. There is also a 4-in 1 version which includes a purging function to remove oxygen and moisture in the chamber which helps solid state pouch cell batteries achieve a better SEI layer during the first cycle. We also have in addition to the standard digital bottle dispenser for electrolyte, automated versions for both pouch and cylinder cells where the electrolyte in injected under vacuum and can be programmed according to your requirements. At the top end we have automatic vacuum sealers which can integrate the electrolyte injection and diffusion and options in between depending on individual requirements. On cylinder cells we also need to groove the cylinder case and then perform a deep weld using a single point welder for the bottom electrode connection before the electrolyte injection and final sealing which can use a crimper similar to those used for coin cells which perform a multi stage crimp, up to floor standing automated crimpers for batch processing. The final stage for a pouch cell would be the final degassing and vacuum heat sealing to produce the finished product.
Once all this has been completed and we have a fully functioning battery, we’re able to support you with the test processes which follow, and we can offer battery analysers in numerous configurations which automatically cycle the cells and record this onto a laptop for analysis, split test cells, Kapton window coin cells and numerous other options depending on the specifics of your research requirements.
We see a number of common pit falls that people can fall into when trying to decide the equipment they require, and one of the most common, believe it or not, is over specifying the equipment selection at an early stage which often is as a result of looking at the higher end possibilities without fully understanding the implications of equipment selection either prior to or following a particular process.
Take an example of pouch cell research and whilst we have a wide range of sizes that people are working with there is an upper limit. Now, as I mentioned earlier, we have a pouch cell electrode cutter which can handle sizes up to 380 x 380mm which at face value might seem like a good investment to allow for size increasing in the future. But, this is much larger than the majority of facilities are currently working on, or would ever work on, and by working through all the required steps outlined here, we would need to upscale all other equipment starting at the coating side in order to provide a fully workable solution. By doing this, we risk spending a huge amount of our budget on something which is desired, however in reality it is never going to be used to its full extent and therefore the capital could have been redirected elsewhere where it could have improved efficiency.
In other cases, we see people being too cautious which is understandable as securing funding is often a lengthy time consuming process sometimes with a very short window after being successful to find a suitable solution. We sometimes find that people will opt for a cheaper alternative in order to try and make full use of their funding, which in the longer term could cost more as equipment can be limited in is functionality making it redundant whenever an institution upscales the project and finds much of the equipment already available needs to be replaced to allow for this expansion.
What we at PI-KEM do as part of our consultancy, is to become involved at the early stages of a project in order to understand from you the current, and longer term plans that you have and any options that you are considering. We understand that at times these are not entirely fixed at the onset of a project and that over time we might take one of several directions, however if we are able to understand these at the outset, then we can work together as a team and explore several options together with their advantages and limitations, so what we end up with is a solution that actually works for you.
Time is another important factor and is something we all wish we had more of. At the beginning of this session I mentioned how it is so easy when looking at the various options available to go off on tangents at the various stages and at times become overwhelmed with what is on offer. Trying to establish what is the best solution, and even at times trying to convince ourselves that a piece of equipment is suitable due to varied reasons, when in fact it doesn’t provide the desired solution we are looking for.
At PI-KEM we’ve worked on numerous projects across the board, from small scale lab to high end pilot line production and everything in between, so whilst every new projects has its unique set of requirements and challenges, there is also a lot of cross over and similarities that we can draw on, which means we are able to provide a quick solution for your requirements that is a bespoke solution for your needs.
It doesn’t just start and end with the equipment either, we’re able to provide the Lithium, Sodium and other chemicals, electrolytes, different material sheets, foils, foams, a wide range of consumables which we hold in stock at our warehouse, the equipment which we have been focusing on today, safety test equipment, wafers, substrates and all other associated equipment.
We can assist you whatever your requirements are, drawing from our extensive in house knowledge and expertise, and if we don’t know we will find out for you and work with you to provide a solution which ultimately will save you time, and money.
I’d like to thank you all for listening to me. Geoffrey Handley-Harrison
If you would like to know more or have a project you would like support with contact PI-KEM at sales@pi-kem.co.uk'
