What is claimed is:
1 . A cap structure of a power battery, comprising a first electrode component, a second electrode component, a cap plate, and a turnable plate, wherein:
the first electrode component and the second electrode component are attached to the cap plate, and the first electrode component is electrically isolated from the cap plate; the first electrode component comprises a first terminal and a first connecting block, the first connecting block is located above the cap plate, the first connecting block comprises a terminal connecting portion, a fusing portion, and a turnable plate connecting portion, the terminal connecting portion is connected to the turnable plate connecting portion through the fusing portion, the first terminal is connected to the terminal connecting portion, the fusing portion has a melting point lower than that of the terminal connecting portion or the turnable plate connecting portion, and the turnable plate is electrically connected to the second electrode component; and in case that an internal pressure of the power battery exceeds a reference pressure, the turnable plate is turned over and in contact with the turnable plate connecting portion, such that the first terminal is electrically connected to the second electrode component.
2 . The cap structure of the power battery of claim 1 , wherein the second electrode component is electrically connected to the cap plate; the cap plate has a turnable plate connecting hole; the turnable plate connecting portion is located above the turnable plate connecting hole; and the turnable plate seals the turnable plate connecting hole and is electrically connected to the cap plate.
3 . The cap structure of the power battery of claim 1 , wherein the second electrode component comprises a second terminal having a turnable plate connecting hole; the turnable plate seals the turnable plate connecting hole and is electrically connected to the second terminal; the cap plate has a turnable plate through hole; the turnable plate connecting portion is located above the turnable plate connecting hole; and the turnable plate connecting hole is aligned with the turnable plate through hole.
4 . The cap structure of the power battery of claim 3 , wherein when the power battery is assembled with the cap structure, a space within the turnable plate through hole and a space below the turnable plate are independent from each other.
5 . The cap structure of the power battery of claim 1 , wherein the first electrode component further comprises a first upper insulating element, and the first connecting block is electrically insulated from the cap plate by the first upper insulating element.
6 . The cap structure of the power battery of claim 5 , wherein the turnable plate connecting portion is fixedly connected to the first upper insulating member.
7 . The cap structure of the power battery of claim 5 , wherein the first upper insulating member has a restriction portion capable of restricting the turnable plate connecting portion from moving upwards.
8 . The cap structure of the power battery of claim 1 , wherein the melting point of the fusing portion ranges from 80° C. to 200° C.
9 . The cap structure of the power battery of claim 8 , wherein the melting point of the fusing portion ranges from 100° C. to 150° C.
10 . The cap structure of the power battery of claim 9 , wherein the fusing portion is made of a metal alloy at least comprising one or more elements of bismuth, tin, lead and zinc.
11 . The cap structure of the power battery of claim 10 , wherein the fusing portion is made of a bismuth-based alloy or a tin-based alloy.
12 . The cap structure of the power battery of claim 11 , wherein the fusing portion is made of a bismuth tin alloy.
13 . The cap structure of the power battery of claim 1 , wherein:
a plurality of first joint surfaces exist between the fusing portion and the terminal connecting portion; and/or a plurality of second joint surfaces exist between the fusing portion and the turnable plate connecting portion.
14 . The cap structure of the power battery of claim 13 , wherein:
one of the fusing portion and the terminal connecting portion has a first groove, the other one has a first ridge corresponding to the first groove, and the first groove and the first ridge corresponding to the first groove are meshed to form the plurality of first joint surfaces between the fusing portion and the terminal connecting portion; and/or one of the fusing portion and the turnable plate connecting portion has a second groove, the other one has a second ridge corresponding to the second groove, and the second groove and the second ridge corresponding to the second groove are meshed to form the plurality of second joint surfaces between the fusing portion and the turnable plate connecting portion.
15 . The cap structure of the power battery of claim 1 , wherein both the fusing portion and the turnable plate connecting portion are located above the turnable plate.
16 . A power battery, comprising a housing, a bare cell, and the cap structure of the power battery of claim 1 , wherein:
the housing accommodates the bare cell; the cap structure covers an opening of the housing; and the bare cell has two electrodes having opposite polarities, one of the two electrodes is electrically connected to the first terminal, and the other one of the two electrodes is electrically connected to the second electrode component.
17 . The power battery of claim 16 , further comprising a fusing member, which is to be connected in series in an electricity output loop of the power battery when the power battery is electrically connected to external electric equipment.
18 . The power battery of claim 17 , further comprising a first connecting element and a second connecting element,
wherein one of the two electrodes is electrically connected to the first electrode component through the first connecting element, and the other one of the two electrodes is electrically connected to the second electrode component through the second connecting element; and wherein the fusing member is formed on the first connecting element and/or the second connecting element.
19 . The power battery of claim 18 , wherein the fusing member is formed by setting a notch and/or a hole on the first connecting element and/or the second connecting element.