By Mike Fritz
Providers in the micromobility supply-chain, including bike shops and self-service rental companies need to be proactive in making sure lithium ion battery fires simply don't happen — because they are preventable!
Vandalism is a possibility at any time and is a criminal act that needs to be deterred and prosecuted, but actual lithium battery fires are a very real possibility that only happen if professional policy and procedures aren't followed.
Let's start by making it very clear that all lithium ion batteries have the potential to be volatile — like gasoline in an automobile gas tank, or other combustibles sitting in your garage, shop, or warehouse. There is a lot of energy stored in a lithium ion battery pack, which is why they are well suited for light electric vehicles. But when that energy is released in an uncontrolled fashion, bad things can and do happen.
But until the battery industry develops fire-proof lithium batteries, there are a number of steps that we, as importers and distributors of electric bikes, can do to minimize the possibility that a battery fire will occur involving the products that we represent. Those steps involve informed battery pack specification setting, and careful, well thought out sourcing.
There are usually two separate entities involved in the production of a lithium ion battery pack intended for use in a LEV: the cell producer and the pack assembler.
Cell producers manufacture the cells that store the energy. Household names like Sony, Samsung, LG and Panasonic are among the most well-known. They have factories dedicated to the process of fabricating the lithium ion cells used in applications like ours.
Battery packs are usually assembled by a third-party. Pack assemblers purchase the lithium cells from the battery manufacturer per the customer's specifications. They test and sort cells based on minute differences in cell capacity. They design and source battery pack housings based on customer requirements. They spot-weld the nickel bus bars that interconnect the cells to create the required voltage and capacity attributes of the pack. Very importantly, the pack manufacturers source, install and program the battery management system (BMS) into the battery pack.
I believe that lithium battery fires occur, in the absence of blatant misuse or abuse, due to deficiencies that are introduced during the cell manufacturing process. Therefore, it is of the utmost importance that cells specified for your battery pack are sourced from a vendor that utilizes manufacturing methods and quality control procedures of the highest caliber.
Equally important is the utilization of a high-quality BMS. The BMS is a microprocessor based on-board electronic device that ensures that the battery pack is always used and maintained within the well-established, mandatory service limitations dictated by the cell manufacturer. But there's more to the BMS than quality electronics. The BMS must be programmed with operating and control parameters that are closely matched to the electrical attributes unique to your particular vehicle.
By carefully specifying and sourcing lithium battery packs for LEV usage, we can go a long way to ensuring that these remarkable energy storage devices are safe and reliable, and perfectly suited for use in our nascent industry.
Please let me know if you have any questions: mikefritz@humanpoweredsolutions.com.
Mike Fritz is the chief technology officer at Human Powered Solutions, LLC.
