A new electronic product will be sensing a Lithium battery while it charges to make a thermal shutdown available. It costs $4 to make. Sell for $14. A ny smart phone can sit on the "Maybe Charge" and if its Lithium battery get s too hot, a Silicon chip comes to the rescue. The socket cuts off the powe r to the charger if it exceeds a temperature of 454 Fahrenheit. Then you ca n feel you did your very best for safety.
Please recommend a $4 electronic design solution. Maybe two components, or ten.