An electric battery cell unit (100a; 100b; 100c) comprising a stack of electrodes comprising a first electrode and a second electrode, a first terminal, a second terminal, and a holder for holding the stack of electrodes, wherein the first terminal is electrically connected to the first electrode, wherein the second terminal is electrically connected to the second electrode, wherein the first and second terminals (102, 104) are attached to the holder, wherein the first terminal comprises a first interface for attachment and electrical connection of the first terminal to a second terminal of another electric battery cell unit, and wherein the second terminal comprises a second interface for attachment and electrical connection of the second terminal to a first terminal of another electric battery cell unit, and wherein the holder comprises a first end portion and a second end portion, wherein the first terminal is located at the first end portion, and wherein the second terminal is located at the second end portion, and wherein the holder has a longitudinal extension extending from the first end portion to the second end portion in a longitudinal direction, and wherein the first interface comprises one or more first contact surfaces for contact with a second terminal of another electric battery cell unit, the one or more first contact surfaces being in parallel to the longitudinal direction, and wherein the second interface comprises one or more second contact surfaces for contact with a first terminal of another electric battery cell unit, the one or more second contact surfaces being in parallel to the longitudinal direction, and characterized in that the one or more first contact surfaces comprises/comprise two stops (130, 132) and a sloping surface extending from one (130, 132) of the two stops (130, 132) of the one or more first contact surfaces to the other one (130, 132) of the two stops (130, 132) of the one or more first contact surfaces, and wherein the one or more second contact surfaces comprises/comprise two stops (136, 138) and a sloping surface extending from one (136, 138) of the two stops (136, 138) of the one or more second contact surfaces to the other one (136, 138) of the two stops (136, 138) of the one or more second contact surfaces. a stack of electrodes comprising a first electrode and a second electrode, a first terminal, a second terminal, and a holder for holding the stack of electrodes, wherein the first terminal is electrically connected to the first electrode, wherein the second terminal is electrically connected to the second electrode, wherein the first and second terminals (102, 104) are attached to the holder, wherein the first terminal comprises a first interface for attachment and electrical connection of the first terminal to a second terminal of another electric battery cell unit, and wherein the second terminal comprises a second interface for attachment and electrical connection of the second terminal to a first terminal of another electric battery cell unit, and wherein the holder comprises a first end portion and a second end portion, wherein the first terminal is located at the first end portion, and wherein the second terminal is located at the second end portion, and wherein the holder has a longitudinal extension extending from the first end portion to the second end portion in a longitudinal direction, and wherein the first interface comprises one or more first contact surfaces for contact with a second terminal of another electric battery cell unit, the one or more first contact surfaces being in parallel to the longitudinal direction, and wherein the second interface comprises one or more second contact surfaces for contact with a first terminal of another electric battery cell unit, the one or more second contact surfaces being in parallel to the longitudinal direction, and characterized in that the one or more first contact surfaces comprises/comprise two stops (130, 132) and a sloping surface extending from one (130, 132) of the two stops (130, 132) of the one or more first contact surfaces to the other one (130, 132) of the two stops (130, 132) of the one or more first contact surfaces, and wherein the one or more second contact surfaces comprises/comprise two stops (136, 138) and a sloping surface extending from one (136, 138) of the two stops (136, 138) of the one or more second contact surfaces to the other one (136, 138) of the two stops (136, 138) of the one or more second contact surfaces.