Cap assembly and power battery

1. A cap assembly for a power battery, wherein the cap assembly comprising:

a cap plate including a top surface, a bottom surface opposed to the top surface in a thickness direction, and a liquid injection hole penetrating through the cap plate from the top surface to the bottom surface and having an inlet provided on the top surface and an outlet provided on the bottom surface; and

a blocking member provided on the bottom surface of the cap plate, wherein a projection of the blocking member in the thickness direction completely covers the outlet of the liquid injection hole,

wherein a fluid channel is formed between the blocking member and the cap plate, and the fluid channel communicates with the outlet of the liquid injection hole, and

wherein the fluid channel is formed at a predetermined angle relative to an axis of the liquid injection hole and has a liquid outlet, so that an electrolyte discharging from the outlet of the liquid injection hole discharges from the liquid outlet of the fluid channel formed by the blocking member and the cap plate after turning at the predetermined angle.

2. The cap assembly according to claim 1 , wherein the cap plate comprises a first end and a second end opposed to the first end in a length direction, and the liquid outlet of the fluid channel faces the first end or faces away from the first end in the length direction.

3. The cap assembly according to claim 2 , wherein the liquid injection hole and the blocking member are provided at the first end.

4. The cap assembly according to claim 3 , wherein the cap plate comprises a boss provided on the bottom surface, disposed in correspondence to the first end, and adapted to press against an electrode assembly of the power battery, wherein the blocking member is connected to the boss and has a bottom face flush with that of the boss.

5. The cap assembly according to claim 3 , wherein the cap assembly further comprises a vent plate which is disposed on the top surface and covers the liquid injection hole, wherein an annular seam is formed between an edge of the vent plate and the top surface of the cap plate, so that the vent plate and the cap plate are hermetically connected.

6. The cap assembly according to claim 5 , wherein an axis of the liquid injection hole is offset from an axis of the vent plate, and the axis of the vent plate is closer to the second end of the cap plate than the axis of the liquid injection hole.

7. The cap assembly according to claim 5 , wherein a ratio of a surface area of the vent plate located inside the annular seam to a cross-sectional area of the liquid injection hole is of 1.5 to 10.

8. The cap assembly according to claim 5 , wherein the top surface of the cap plate is provided with a recess depressed toward the bottom surface, wherein the liquid injection hole communicates with the recess and the vent plate is accommodated in the recess.

9. The cap assembly according to claim 1 , wherein the blocking member and the cap plate are formed as an integral structure.

10. A power battery, wherein comprising:

a case having an opening;

an electrode assembly formed by a positive electrode sheet, a negative electrode sheet, and a separating membrane provided between the positive electrode sheet and the negative electrode sheet that are wound around a winding axis, the electrode assembly having two end portions opposed to each other along the winding axis, the electrode assembly being disposed in the case; and

a cap assembly for covering the opening of the case and disposed in correspondence to the end portion of the electrode assembly,

wherein the cap assembly comprising:

a cap plate including a top surface, a bottom surface opposed to the top surface in a thickness direction, and a liquid injection hole penetrating through the cap plate from the top surface to the bottom surface and having an inlet provided on the top surface and an outlet provided on the bottom surface; and

a blocking member provided on the bottom surface of the cap plate, wherein a projection of the blocking member in the thickness direction completely covers the outlet of the liquid injection hole,

wherein a fluid channel is formed between the blocking member and the cap plate, and the fluid channel communicates with the outlet of the liquid injection hole,

wherein the blocking member is disposed between the cap plate and the end portion of the electrode assembly, and

wherein the fluid channel is formed at a predetermined angle relative to an axis of the liquid injection hole and has a liquid outlet, so that an electrolyte discharging from the outlet of the liquid injection hole discharges from the liquid outlet of the fluid channel formed by the blocking member and the cap plate after turning at the predetermined angle.

11. The cap assembly according to claim 10 , wherein the cap plate comprises a first end and a second end opposed to the first end in a length direction, and the liquid outlet of the fluid channel faces the first end or faces away from the first end in the length direction.

12. The cap assembly according to claim 11 , wherein the liquid injection hole and the blocking member are provided at the first end.

13. The cap assembly according to claim 12 , wherein the cap plate comprises a boss provided on the bottom surface, disposed in correspondence to the first end, and adapted to press against an electrode assembly of the power battery, wherein the blocking member is connected to the boss and has a bottom face flush with that of the boss.

14. The cap assembly according to claim 12 , wherein the cap assembly further comprises a vent plate which is disposed on the top surface and covers the liquid injection hole, wherein an annular seam is formed between an edge of the vent plate and the top surface of the cap plate, so that the vent plate and the cap plate are hermetically connected.

15. The cap assembly according to claim 14 , wherein an axis of the liquid injection hole is offset from an axis of the vent plate, and the axis of the vent plate is closer to the second end of the cap plate than the axis of the liquid injection hole.

16. The cap assembly according to claim 14 , wherein a ratio of a surface area of the vent plate located inside the annular seam to a cross-sectional area of the liquid injection hole is of 1.5 to 10.

17. The cap assembly according to claim 14 , wherein the top surface of the cap plate is provided with a recess depressed toward the bottom surface, wherein the liquid injection hole communicates with the recess and the vent plate is accommodated in the recess.

18. The cap assembly according to claim 10 , wherein the blocking member and the cap plate are formed as an integral structure.