IPhone 8 battery failure

18 months after purchase, the battery in my iPhone 8 began to fail, with unexpected shut-downs so frequent that it was impossible to use. I have replaced it, but kept it. Today I find that whatever chemical process takes place within the battery, it had expanded with such force that it partially blew off the screen. There is no sign of combustion, but it is an indication of what potentially dangerous items we casually carry in our pocket!