The present application discloses a battery cell module and a battery system. The battery cell module includes a plurality of battery cell assemblies. Each of the battery cell assemblies includes a battery cell, an end cover, and a base. A first end of the battery cell is connected to the end cover, and a second end of the battery cell is connected to the base. End covers of adjacent ones of the battery cell assemblies are detachably connected to each other, and bases of the adjacent ones of the battery cell assemblies are detachably connected to each other. Each of battery cells is provided with one of the end covers and one of the bases, a plurality of battery cells are grouped by a detachable connection between adjacent end covers and a detachable connection between adjacent bases, which is convenient for assembly of the battery cell module and beneficial to improve relative position accuracy between the battery cells, thereby improving assembly accuracy of the battery cell module. By adopting the above battery cell module, the battery system has high processing precision and a reliable structure.