This Seeking alpha article, https://seekingalpha.com/article/4122202-ballard-power-systems-rapidly-growing-heavy-duty-sector, explains the main sector that is the driving force of this business. It also, is the reason for the recent surge in stock price and makes it a very safe play, in terms of minimal risk.
BLDP is currently ramping up production for buses/trams in china and is seeing a decent ramp-up in production for these orders. They also recently signed a deal with a Toyota subsidiary in japan for distribution and is expecting news soon. Chart wise--- If a new low establishes itself above 1.92 we could remain in this bullish uptrend