Battery moulds are ideally suited to the manufacture of solid walls that are formwork-smooth on both sides with high surface quality. With the help of a butterfly formwork, the development department at B.T. innovation GmbH has now developed a new process with which sandwich walls that are formwork-smooth on both sides can also be produced. The newly developed butterfly formwork combines the advantages of the horizontal preparation and the upright manufacture of precast concrete elements. It opens up new possibilities for the use of battery moulds.