The invention provides a battery pack battery (2) comprising a battery shell (3) provided with an electrode unit (10) therein, wherein the electrode unit (10) comprises an anode (21) connected with a negative terminal and a cathode (22) connected with a positive terminal. The electrode unit (10) is configured to be an electrode stack which comprises multiple layers of the anode (21) and multiple layers of the cathode (22), wherein the layers are stacked in a vertically overlapping manner in a stacking direction (x). The battery shell (3) is in the shape of a prism, wherein all surfaces of the battery shell (3) are parallel to the stacking direction (x) or extending at a right angle to the stacking direction (x). The battery shell (3) has a first shell part (61) forming the negative terminal (11) and a second shell part (62) forming the positive terminal (12).