Portable electric cup boiling water can be covered?

Portable electric cup is easy to use, many friends will carry when traveling, some electric cup in the instruction manual will be marked: "boil water prohibited when closing the lid", the general requirements of the water after one minute and then close the lid, which is mainly to prevent the user from being scalded, then the electric cup of water can be covered with a lid?
General portable electric cup, boiling water can not be covered, because the water boiling, when the water vapor will produce a lot of air pressure, if the lid burning, on the one hand, may be due to air pressure can not be opened, on the other hand, there is a risk of steam scalded users, so can not be covered.
However, there are smart electric cup can be covered with a lid to boil water, which requires electric cup with temperature control protection device, water boiling instantly jump off; and also have the pressure relief technology, - some electric cup production will be built in the lid of the breathable membrane, automatically upward release of air pressure when the water is cooking, the lid wall set pressure relief valve mouth, air pressure from the valve mouth, so that the realization of the cover cover the demand for water, and not afraid of floating into the dust when boiling, on the other hand, there is a risk of steam burns the user, so you can not cover the lid. And not afraid to boil water when floating into the dust and foreign objects, and do not have to worry about boiling water splash burns people, more secure.