The PGS37

Legislation and regulations: The PGS37

The energy transition means among other things an intensification of worldwide battery usage. Especially the usage of the efficient, rechargeable energy carriers has expanded significantly. The expectation is that the use of these energy carriers will grow exponentially in multiple applications: in households, vehicles and energy storage systems (ESS). Although lithium-ion energy carriers do not form a huge risk, if used correctly, there are a couple of smaller risks. For example: a thermal runaway may be caused by overheating, which can lead to extreme explosions, fires and the release of toxic materials. Incidents with lithium-ion batteries in which this type of energy carrier is involved, risks for the area cannot be avoided. This is especially the case whenever multiple cells are involved, all placed near each other. In reality, this will occur with the storage of lithium-ion energy storage systems or after the use of and application of lithium-ion energy storage systems in a bigger ESS.  Proven is that there is an urgent need for guidelines that increase safety in the workplace. That is why the PGS37 will be introduced shortly.

Energy storage systems and batteries

The term lithium-ion energy storage systems is used because of the fact that this contains both separate cells and batteries. Whenever the term ‘energy storage systems’ is used, lithium-ion energy storage systems are meant. If one or more cells are equipped with a so called BatteryManagementSystem (BMS), we are talking about a battery. Lithium-ion energy storage systems include lithium-ion polymer energy storage systems. With the storage of energy storage systems, (future) legislation and regulations will be primarily about cells or batteries that are out of order. These are energy storage systems that have been mounted in the time of usage of electronics, tools or vehicles, like scooters, bikes and cars in use.

The risks

The risks concerning lithium-ion energy storage systems have been mentioned in the first section. One of the crucial factors is thermal runaway. Underlying causes can be (combinations of) production defects, design defects or malfunctions in the BMS causing an overload, external factors like vibrations, shocks or damage by impact, by falling, collisions, fires or lightning strikes. Besides that, ageing or discharging can lead to failures of the lithium-ion energy carrier, that can lead to ignition. A source of risk can also be improper maintenance or improper assembly and repairs. This, for example, by incorrectly replacing (temperature) sensors or (groups of) lithium-ion energy carriers in a unit. This can result in an unbalanced composition of a battery. The biggest dangers of ignition are high temperatures, and strong heat radiation from a lithium-ion energy carrier in the event of a fire and the formation of toxic fumes containing hydrogen fluoride and lithium hydroxide and other toxic decomposition products. The latter is partly dependent on the composition of the lithium-ion energy carrier, in particular the composition of the electrolyte. Flammability is caused by the electrolyte decomposing and reacting with moisture from the air. In that case, the electrolyte is dissolved in a flammable organic solvent. When ignited, the lithium can react with moisture and oxygen from the air. Tests at TU Eindhoven and practical situations have also shown that lithium-ion energy carriers, that switch to thermal runaway, sometimes ignite and other times do not. In the latter case, there is only a chemical reaction that involves high temperatures, the release of toxic gases and physical explosions, as the shell collapses under the pressure of the gases. Once a thermal runaway takes place with a lithium-ion energy carrier or a group of lithium-ion energy carriers, the situation is extremely difficult to stabilize. This is because all ingredients to maintain a fire are present in a lithium-ion cell. For example, no external oxygen is needed to maintain the fire. Because several cells are often packed together, there is a good chance that overheating of one cell will lead to overheating of the other cells, causing a chain reaction. The bundling of cells also hinders accessibility, which will also limit the options for control. This is even more the case for densely placed cell packs. There will only be a safe situation again when all electrical and chemical energy from the energy carrier has been neutralised. Therefore, fire containment packaging is key to safely store batteries and other energy storage systems.

Battery storage

The way in which the storage of lithium-ion energy carriers is organised also determines the safety. Storage of lithium-ion energy carriers at companies takes place on a scale ranging from a few pieces to several tons. It goes without saying that this has consequences for the way in which the lithium-ion energy carriers can be stored safely, including the extend of safety provisions. Although the storage of packaged energy carriers does not fall within the scope of the PGS-15 (storage of packaged hazardous substances), elements from that PGS-15 are useful for handling in the storage of lithium-ion energy carriers. Partly in that context, it is useful to distinguish four scale levels with associated storage facilities:

1. big: in a fire compartment
2. medium: in a fire-safe storage safe
3. average: in a fire-safe storage cabinet (up to 1.5 m3 per cabinet)
4. small: in a fire-safe packing, bag, envelope, suitcase, box or barrel.

FireCon offers you the solution for all four scale levels. These solutions are based on years of development in the most challenging markets, namely aviation and EV racing. Involvement in the realisation of the PGS37 underlines FireCon’s knowledge and experience. Do you have any questions about the current guidelines or the realisation of the PGS37? Contact us here!