Method to produce a battery for energy storage

A production method of an energy storage battery comprising the steps of:

• providing an electrochemical cell, which is at least partially complete and provided with an electrical collector;
• providing a container having a first wall;
• placing, on an outer surface of the first wall, an outer body that constitutes an electrical pole of the battery;
• inserting the electrochemical cell into the container bringing the electrical collector adjacent the first wall;
• providing the electrical collector with access from the outside of the container to allow a weld between the electrical collector and the outer body, and
• welding the electrical collector and the outer body to one another at said access to establish an electrical connection, wherein
• said access comprises a first through hole made in the first wall and a second hole made in the outer body and arranged at least partially aligned with the first through hole, when the outer body is arranged on the outer surface of the first wall and the weld is made at the second hole,
• the electrical collector has no protrusion and the weld is made inside the second hole of the outer body.