Pole piece, battery cell, battery module and battery pack

The invention relates to a pole piece, a battery cell, a battery module and a battery pack. At least one groove is formed in the side wall of the pole piece; at least one tab is arranged in the at least one groove; and a gap is formed between the tab and the side wall of the groove. According to the pole piece provided by the invention, at least one groove is formed in the side wall and serves as a tab folding area, so that the length of the tab protruding out of the pole piece is shortened, the structure of the pole piece is compact, and the space utilization rate when the pole piece is used for a battery cell is improved. 本发明涉及一种极片、电芯、电池模组及电池包，所述极片的侧壁设置至少1个凹槽；所述至少1个凹槽中设置有至少1个极耳；所述极耳与所述凹槽的侧壁具有间隔。本发明提供的极片在侧壁设置至少1个凹槽，使凹槽作为极耳收拢区，缩短了极耳突出极片的长度，从而使极片的结构紧凑，提高了其用于电芯时的空间利用率。