A power battery, comprising: a shell; a plurality of electric cores disposed in the shell and having a tab at an end thereof; and a battery spacer comprising: a spacer body; a plurality of protrusions, each protrusion being protruded from an inner surface of the spacer body, extended in a longitudinal direction of the spacer body, and formed by recessing a portion of an outer surface of the spacer body; and a plurality of grooves formed in the outer surface of the spacer body, each groove corresponding to the protrusion respectively and formed by recessing the portion of the outer surface of the spacer body; wherein the battery spacer is located between the tab and the shell, and the tab is received within a positioning area formed between adjacent protrusions such that the tab is held and positioned by the adjacent protrusions, wherein the tab is preferably configured as a winding tab, and the positioning area preferably has a shape matched with that of the winding tab; characterized in that the battery spacer further comprises a plurality of liquid guiding slots formed in the outer surface of the spacer body and extended from the grooves to an edge of the spacer body respectively; and that the power battery further comprises a reinforcing plate disposed within the groove; wherein the reinforcing plate is disposed in a lateral direction of the spacer body, and defines an upper surface obliquely extended downwards from inside to outside and a lower surface. a shell; a plurality of electric cores disposed in the shell and having a tab at an end thereof; and a battery spacer comprising: a spacer body; a plurality of protrusions, each protrusion being protruded from an inner surface of the spacer body, extended in a longitudinal direction of the spacer body, and formed by recessing a portion of an outer surface of the spacer body; and a plurality of grooves formed in the outer surface of the spacer body, each groove corresponding to the protrusion respectively and formed by recessing the portion of the outer surface of the spacer body; a spacer body; a plurality of protrusions, each protrusion being protruded from an inner surface of the spacer body, extended in a longitudinal direction of the spacer body, and formed by recessing a portion of an outer surface of the spacer body; and a plurality of grooves formed in the outer surface of the spacer body, each groove corresponding to the protrusion respectively and formed by recessing the portion of the outer surface of the spacer body; wherein the battery spacer is located between the tab and the shell, and the tab is received within a positioning area formed between adjacent protrusions such that the tab is held and positioned by the adjacent protrusions, wherein the tab is preferably configured as a winding tab, and the positioning area preferably has a shape matched with that of the winding tab; characterized in that the battery spacer further comprises a plurality of liquid guiding slots formed in the outer surface of the spacer body and extended from the grooves to an edge of the spacer body respectively; and that the power battery further comprises a reinforcing plate disposed within the groove; wherein the reinforcing plate is disposed in a lateral direction of the spacer body, and defines an upper surface obliquely extended downwards from inside to outside and a lower surface.