An electrical connection device, comprising: a vehicle side electrical connector including a first mounting seat, a first high-voltage assembly and a first low-voltage assembly, wherein the first high-voltage assembly and the first low-voltage assembly are configured to be inserted through the first mounting seat; a battery side electrical connector including a second mounting seat, a second high-voltage assembly and a second low-voltage assembly, wherein the second high-voltage assembly and the second low-voltage assembly are configured to be inserted through the second mounting seat, wherein the first high-voltage assembly is in a separable floating electrical connection with the second high-voltage assembly, wherein the first low-voltage assembly is in a separable planar electrical connection with the second low-voltage assembly, wherein the first mounting seat is in a detachable sealing connection with the second mounting seat, and wherein the first mounting seat is opposite to the second mounting seat; the first high-voltage assembly includes a first high-voltage pole, and the first high-voltage pole includes an electrical contact end and a wiring end; the first high-voltage assembly also includes a flexible electrical connector and a high-voltage plug; one end of the flexible electrical connector is in a floating electrical connection with the wiring end of the first high-voltage pole, the other end of the flexible electrical connector is in a floating electrical connection with the high-voltage plug; characterized in that the flexible electrical connector is configured to adapt the relative displacement change in axial, radial and all directions between the first high-voltage pole and the high-voltage plug by a flexible cavity made of flexible conductive material. a vehicle side electrical connector including a first mounting seat, a first high-voltage assembly and a first low-voltage assembly, wherein the first high-voltage assembly and the first low-voltage assembly are configured to be inserted through the first mounting seat; a battery side electrical connector including a second mounting seat, a second high-voltage assembly and a second low-voltage assembly, wherein the second high-voltage assembly and the second low-voltage assembly are configured to be inserted through the second mounting seat, wherein the first high-voltage assembly is in a separable floating electrical connection with the second high-voltage assembly, wherein the first low-voltage assembly is in a separable planar electrical connection with the second low-voltage assembly, wherein the first mounting seat is in a detachable sealing connection with the second mounting seat, and wherein the first mounting seat is opposite to the second mounting seat; the first high-voltage assembly includes a first high-voltage pole, and the first high-voltage pole includes an electrical contact end and a wiring end; the first high-voltage assembly also includes a flexible electrical connector and a high-voltage plug; one end of the flexible electrical connector is in a floating electrical connection with the wiring end of the first high-voltage pole, the other end of the flexible electrical connector is in a floating electrical connection with the high-voltage plug; characterized in that the flexible electrical connector is configured to adapt the relative displacement change in axial, radial and all directions between the first high-voltage pole and the high-voltage plug by a flexible cavity made of flexible conductive material.