There have been safety standards for e-bike batteries recently mandated by law in places like NYC, but there is still a lot of lacking enforcement and mandatory checks. Every other week, you hear an instance of a person's apartment or repair shop set on fire due to faulty e-bike batteries :(
Yeah, often it seems to be delivery drivers who are really hard on their batteries. There is a grey market to repair them when cells go bad and they often use low quality replacements or override some of the safety circuitry built into a lot of the batteries.
