I have a smartphone that I bent yesterday. I have no idea what could happen. Is it dangerous?

The smartphone is from Huawei and has a Li-ion battery. Could it explode while charging? I have no idea. More precisely: a Huawei P Smart 2018.

Your suspicion is justified. In the li-ion batteries, only a wafer-thin plastic layer separates the two components, which can burn or explode in direct contact.

in the case of such massive damage, it can't be ruled out that the thing will go up in the air even when it is switched off.

Maybe you just had it in your pocket when you sat down 😎