A power battery device, comprising: a battery tray having a positioning member provided on the upper surface thereof; and a plurality of battery modules disposed on the battery tray and arranged in at least two layers in an up-down direction, each battery module comprising: a housing having a first positioning portion disposed on the upper surface of the housing and a second positioning portion disposed on the lower surface of the housing; a battery disposed within the housing, wherein in two adjacent layers of the battery modules, the first positioning portion on the upper surface of the housing in a lower layer the battery modules is matched with the second positioning portion on the lower surface of the housing in an upper layer of the battery modules, and the battery modules in the lowermost layer of the battery modules are positioned by the positioning member on the upper surface of the tray, wherein the first positioning portion is configured as a positioning projection, and the second positioning portion is configured as a positioning groove adapted for matching with the positioning projection; wherein the positioning projection comprises: a first positioning projection disposed in the middle of the upper surface of the housing in the front-rear direction; and the positioning groove comprises: a first positioning groove disposed in the middle of the lower surface of the housing in the front-rear direction; wherein the first positioning projection is extended in a left-right direction of the housing; and the first positioning groove is extended in the left-right direction of the housing; characterized in that the positioning projection comprises: a second positioning projection disposed on an edge of the upper surface of the housing in a left-right direction; and wherein the positioning groove comprises: a second positioning groove disposed on an edge of the lower surface of the housing in the left-right direction; wherein the second positioning projection is extended in the left-right direction of the housing; and wherein the second positioning groove is extended in the left-right direction of the housing. a battery tray having a positioning member provided on the upper surface thereof; and a plurality of battery modules disposed on the battery tray and arranged in at least two layers in an up-down direction, each battery module comprising: a housing having a first positioning portion disposed on the upper surface of the housing and a second positioning portion disposed on the lower surface of the housing; a battery disposed within the housing, a housing having a first positioning portion disposed on the upper surface of the housing and a second positioning portion disposed on the lower surface of the housing; a battery disposed within the housing, wherein in two adjacent layers of the battery modules, the first positioning portion on the upper surface of the housing in a lower layer the battery modules is matched with the second positioning portion on the lower surface of the housing in an upper layer of the battery modules, and the battery modules in the lowermost layer of the battery modules are positioned by the positioning member on the upper surface of the tray, wherein the first positioning portion is configured as a positioning projection, and the second positioning portion is configured as a positioning groove adapted for matching with the positioning projection; wherein the positioning projection comprises: a first positioning projection disposed in the middle of the upper surface of the housing in the front-rear direction; and the positioning groove comprises: a first positioning groove disposed in the middle of the lower surface of the housing in the front-rear direction; wherein the first positioning projection is extended in a left-right direction of the housing; and the first positioning groove is extended in the left-right direction of the housing; characterized in that the positioning projection comprises: a second positioning projection disposed on an edge of the upper surface of the housing in a left-right direction; and wherein the positioning groove comprises: a second positioning groove disposed on an edge of the lower surface of the housing in the left-right direction; wherein the second positioning projection is extended in the left-right direction of the housing; and wherein the second positioning groove is extended in the left-right direction of the housing.