Can(’t) Slovak electric vehicle batteries  catch fire during production?

Soon, we could be driving electric vehicles with Slovak batteries. How, and where, will these be manufactured? And what impact will their manufacturing have on our environment?

Today, laptops can last up to 12 hours without the need to be charged; you can drive an electric vehicle from Bratislava to Košice on a single charge; and, while you exhaust yourself trying to ride a bike up to Popradské pleso, a group of pensioners can easily overtake you on their e-bikes. It sounds funny, but two years ago, Akira Yoshino deservedly received a Nobel prize in chemistry for this very concept (along with M. Stanley Whittingham and John B. Goodenough). What do I find the most interesting about new inventions? In 1985, when Akira Yoshino created the first prototype of a safe lithium battery suitable for manufacturing, he certainly had no clue how the world would change in the 21st century. It was his invention, and the unique properties of li-ion batteries, that paved the way for many subsequent devices and inventions. Slovakia, too, has started building on Yoshino’s foundations. 

I won’t talk about the production of a lithium-ion battery, as I’d rather leave this discussion for my other colleagues and their future blog posts. What I’d like to focus on today are the spaces which can help research, develop, improve and manufacture these kinds of batteries. All of these processes would be impossible without having a suitable space to carry them out. In Voderady, we’re currently building a unique R&D centre that fits the requirements to a T.


The materials for the manufacturing of EV batteries are extremely sensitive to humidity. Their properties change when they get into contact with water and the batteries deteriorate quickly. Therefore, the battery mixtures must be prepared in the cleanest and driest areas possible. In the new R&D centre in Voderady, we’re planning to utilise so-called ultra-dry environments. In manufacturing, we’ll use recipes that are based on a higher nickel content, using silicone-based anodes — this is currently the most up-to-date trend for ensuring the li-ion batteries’ best properties. The recommended humidity, ideal for humans, is around 40 to 60%. In Voderady, however, we’ll need to keep the humidity level at 0.5%, at most, which we’ll achieve by using powerful industrial dehumidifiers. In practice, a humidity of 0.5% translates to a dew point of -40°C on the centre’s premises. That’s unpleasant to imagine, isn’t it? Moreover, the assembly of modern battery cells and the filling of batteries with electrolyte requires the environment to stay dry at a dew point of -60 to 70°Ct, which represents a humidity of 0.01°C! Any entry into these areas must, then, be carefully considered, as to account for the temporary breach of ultra-dry conditions — and we are paying close attention to this. Do you know the ALARA principle, used in nuclear power plants? InoBat is using something similar. We are going to limit the number of people in these areas, through production automation, and by cutting down the maximum amount of time necessary for the employees to be involved in the production process — so as to avoid any potential risks. 


Whether we like it or not, we need to use the organic solvent N-methyl-2-pyrrolidone (NMP) in Voderady. This solvent is used to dissolve the binder, when forming the powder made of nickel, manganese, cobalt, lithium, and carbon. Currently, there is nothing that could replace NMP in this process, and so we must use it as well. At InoBat, however, we approach its use carefully, and we insist on using the latest technologies, which can limit the hazards that the solvent could present to our workers and residents of the nearby areas.


In Slovakia, the limits for discharging NMP into the air are set at 1 mg/m3. At InoBat Auto, we are aiming to lower this limit even further — that’s why we are using the so-called NMP Recovery System, a technology designed to recover discharged NMP. The materials with the cathode mixture are dried in electric ovens, to achieve an almost complete evaporation of toxic NMP. The electrodes are further dried in vacuum ovens. All of the evaporated NMP is recovered with a series of condensator and concentrator units. The result? The final amount of NMP that’s discharged into the air is several hundred times smaller than the official limit set in Slovakia, and we can recover up to 99.99% of the evaporated NMP. Subsequently, we’ll collect it in tanks, transport it to a distributor for processing, and the captured NMP will be further recycled and reused after purification.

Unfortunately, some factories in China don’t demand NMP recovery systems, and their limits are much less strict. That’s why it’s important that the manufacturing of EV batteries should be carried out as close to the point of consumption as possible, and that it should be governed by strict European standards. This way, we’ll guarantee a significantly lower impact on our planet — in terms of minimising our carbon footprint, but also the amount of air emissions.


You’ve certainly heard that electric vehicle batteries make putting out a fire problematic. You’ve probably seen videos with EVs on fire, too. Yes, fires can happen. But the risk of an EV blaze is statistically equal to that of a traditional combustion-engine vehicle. In Voderady, we don’t need to worry about fires at all. The fire protection system in our facilities is designed in a way that prevents them, and the risk is further minimised by splitting the protection into two functional units:

  • from the manufacturing of electrodes and the assembly of battery cells, to their impregnation with electrolyte
  • the ageing and formation of batteries, when they’re charged for the first time (here, the batteries already bear their characteristic properties)

The protection system of the first unit is easy: traditional water-based fire protection, specifically adapted for use in our ultra-dry areas. The second unit is a little more complicated. Here, the extinguishers are still water-based, but the system focuses on extinguishing problematic battery cells instead of the room as a whole. In the ageing and formation processes, the battery goes through charge, discharge and aging cycles, which happen at various temperatures. During these processes, individual cells are placed into so-called “trays”, in multiple separate parts. These are subsequently placed into units with an automatic system, which controls their formation, and, if necessary, can extinguish a problematic tray. Our technology can also separate the corrupted parts, for example by placing them into saltwater or safety storage cabinets, where the battery safely burns itself out. At InoBat Auto, the whole process will be automated.


For those who’d like to know more about this topic, here are some interesting behind-the-scenes facts:

  • Our batteries have their own sauna! During battery formation, one of the processes takes place at a temperature of 40-60°C. At this point, the batteries are placed into a room with a stable required temperature, and they’re kept in this “sauna” for several hours or days, as they mature. 
  • The batteries’ carbon footprint mostly depends on the source of the used electricity. In Slovakia, the carbon footprint of electricity is, on average, around 110 gCO2/kWh. If we need around 35 kWh to produce one InoBat battery cell, its carbon footprint is roughly 3,8 kg CO2. But let’s look even further! If we put the Slovak Inobat batteries into an EV with a battery capacity of 50 kWh (with range around 300km), then the energy put into their manufacturing is equivalent to the carbon footprint of around 6000km driven in a traditional middle or lower-range car. And that’s not much at all.
  • We’re approaching the design of our facilities responsibly, by utilising all the space we have available — through installing photovoltaic panels, planting more greenery, reducing concrete areas and using modern energy storage. 
  • We want to have all internal parking spaces equipped with charging stations for electric cars.

Working at InoBat gives me the unique opportunity to be at the birth of a company whose goal is to bring a completely new type of industrial production and meaningful technological innovations. I believe that InoBat can bring our dreams of a greener European future closer to reality, and that one day we’ll all have a chance to buy an EV with genuine Slovak batteries! I joined InoBat a little over a year ago and I’m one of the first full-time members who’ve had the chance to define the company’s baby steps — ones that will lead to the successful construction of our R&D centre, but also the first Slovak gigafactory. And, looking at the team of people who’ve joined us in the last few months, I’m certain we’ll accomplish our goal.

I hope that you’ve enjoyed reading about these technical behind-the-scenes facts and figures. If you’d like to learn even more interesting info, I recommend that you watch the videos we’ve prepared for BATTERYacademy, our year-long educational program. After the kick-off episode with Oto Pisoň, we’ll bring you a brand new episode this Friday — with none other than the legend of the automotive industry himself, Andy Palmer. Together, we’ll debunk some common myths from the world of e-mobility. We’re planning to bring you even more interesting videos by the end of the year, so make sure to keep an eye on our channel: 

Stanislav Pecko
Project Manager, InoBat Auto