Battery pack, electrical device, and charging device

1. A battery pack, comprising:

one or more battery cells in a battery case; and

a connector portion including a first terminal portion, wherein the connector portion is configured to be detachably engaged with a connection portion of an electrical device or a charging device including a second terminal portion and a drain hole, wherein the first terminal portion is configured to be connected to the second terminal portion,

wherein the connector portion is configured to be detachably engaged with the connection portion by rotation, thereby closing the drain hole by a part of the connector portion,

wherein the connector portion includes a tubular peripheral wall portion, a plurality of engaging portions and positioning space portions, and the engaging portions are extending radially outward from a sealing member pressing portion of the connector portion,

wherein the tubular peripheral wall portion fits into an opening of the battery case, and

wherein the first terminal portion is provided in the engaging portions and the engaging portions are outside the battery case.

2. The battery pack according to claim 1 , further comprising a sealing member disposed on the connector portion,

wherein the connector portion is configured to be moved toward the connection portion in a rotation axis direction with rotation so as to provide a press engagement associated with the sealing member.

3. The battery pack according to claim 2 , wherein the connector portion is in the press engagement with the sealing member thereby covering the drain hole.

4. The battery pack according to claim 1 , wherein the drain hole is closed by the part of the connector portion having moved in a rotational direction.

5. The battery pack according to claim 1 , wherein

the connection portion includes a second engagement portion, and

wherein the connector portion includes a first engagement portion that is configured to be engaged with the second engagement portion by rotation.

6. The battery pack according to claim 5 , wherein the first engagement portion and the second engagement portion are provided along the rotational direction.

7. The battery pack according to claim 5 ,

wherein the first terminal portion includes spring contact members disposed opposite in arrangement, and

wherein the second engagement portion is in a fixed state upon insertion in an opposed gap of the spring contact members.

8. The battery pack according to claim 5 , wherein the first engagement portion includes a threaded groove portion.

9. The battery pack according to claim 5 , wherein the first engagement portion includes a lock portion.

10. The battery pack according to claim 1 , further comprising

a battery holder in which the battery cells are housed.

11. The battery pack according to claim 10 , wherein in the battery holder, the battery cells are arranged and fixed with a rotationally symmetrical shape in a plan view.

12. The battery pack according to claim 10 , wherein

the battery case includes a first end face being opened, a second end face opposed to the first end face, and a peripheral face coupling between the first end face and the second end face, and wherein the battery case houses the battery holder and the battery cells, and wherein the first end face is closable by the connector portion.

13. The battery pack according to claim 12 , wherein the case includes a grip portion provided on the second end face.

14. The battery pack according to claim 12 , wherein the case has a cylindrical shape.

15. The battery pack according to claim 12 , wherein a circuit board for controlling charging and discharging of the battery cells is housed in the case.

16. The battery pack according to claim 12 , wherein the case has a hollow structural body.

17. An electrical device, comprising:

a battery pack; and

an electrical device body having a connection portion that includes a second terminal portion and a drain hole,

wherein

the battery pack includes

one or more battery cells in a battery case; and

a connector portion including a first terminal portion, wherein the connector portion is configured to be detachably engaged with the connection portion of the electrical device body,

wherein the first terminal portion is configured to be connected to the second terminal portion,

wherein the connector portion is configured to be detachably engaged with the connection portion by rotation, thereby closing the drain hole by a part of the connector portion,

wherein the connector portion includes a tubular peripheral wall portion, a plurality of engaging portions and positioning space portions, and the engaging portions are extending radially outward from a sealing member pressing portion of the connector portion,

wherein the tubular peripheral wall portion fits into an opening of the battery case, and

wherein the first terminal portion is provided in the engaging portions and the engaging portions are outside the battery case.