Secondary battery, battery pack and electric device
A secondary battery, a battery pack, and an electric device. The secondary battery includes: a case with an inner cavity in which an electrolyte is included; a cap assembly covering an opening of the case; and an electrode assembly located in the inner cavity, the electrode assembly including an electrode unit and tabs, and along a length direction, the electrode unit including two side portions disposed oppositely, the tabs extending from the side portions; a connecting component configured to connect the tabs and the cap assembly; a flow guiding component located between a corresponding connecting component and a corresponding side portion, being connected to the connecting component and provided with an avoiding portion configured to avoid the tabs, and being in contact with the electrolyte, at least part of the flow guiding component being in contact with the corresponding side portion, and the flow guiding component.
1. A secondary battery, comprising:
a case comprising an opening and an inner cavity, an electrolyte being comprised in the inner cavity;
a cap assembly covering the opening;
an electrode assembly located in the inner cavity and comprising an electrode unit and tabs; along a length direction, the electrode unit comprising two side portions disposed oppositely, and the tabs extending from the side portions;
connecting components configured to connect the tabs and the cap assembly; and
a flow guiding component located between a corresponding connecting component and a corresponding side portion and connected to the corresponding connecting component, at least part of the flow guiding component being in contact with the corresponding side portion, and the flow guiding component being in contact with the electrolyte,
wherein the flow guiding component is provided with an avoiding portion configured to avoid the tabs, and along a height direction, a height of the flow guiding component is greater than or equal to a height of the electrode assembly and the flow guiding component is configured to guide electrolyte at a bottom of the base to the electrode assembly.
2. The secondary battery according to claim 1 , wherein:
each of the tabs comprises a body portion and an extension portion, the body portion extending from the corresponding side portion, and the extension portion being bent relative to the body portion; and
at least part of the body portion being located in the avoiding portion.
3. The secondary battery according to claim 2 , wherein:
the avoiding portion is a recess;
along a height direction, the recess comprises a first side wall and a second side wall disposed oppositely, and the first side wall and the second side wall abut against the body portion, respectively; and
along a width direction, the recess comprises a third side wall, and the third side wall abuts against the body portion.
4. The secondary battery according to claim 1 , wherein:
the flow guiding component is a plate-shaped structure; and
along a width direction, one end of the flow guiding component is fixedly connected to the corresponding connecting component, and the other end is attached to the corresponding side portion.
5. The secondary battery according to claim 1 , wherein:
along a width direction, a width of the flow guiding component is smaller than a width of the connecting components.
6. The secondary battery according to claim 1 , wherein:
each of the connecting components comprises a first connecting portion and a second connecting portion, the first connecting portion being configured to connect to the cap assembly, the second connecting portion being configured to connect to a tab, and the first connecting portion being bent relative to the second connecting portion;
along a height direction, one end of the flow guiding component extends to a position where the first connecting portion and the second connecting portion are bent relative to each other, and the other end of the flow guiding component abuts against a bottom of the case; or,
the secondary battery further comprises an insulating membrane located between the case and the electrode assembly, and along a height direction, one end of the flow guiding component extends to a position where the first connecting portion and the second connecting portion are bent relative to each other, and the other end of the flow guiding component abuts against a bottom of the insulating membrane.
7. The secondary battery according to claim 1 , wherein:
the electrode assembly comprises a plurality of anodic plates, a plurality of cathodic plates, and a plurality of separators, and the separators are located between the anodic plates and the cathodic plates that are adjacent;
along a width direction, each of the separators comprises first end portions that extend beyond the anodic plates and the cathodic plates; and
a thickness of the flow guiding component is greater than or equal to a distance between a first end portion and a connecting component corresponding thereto.
8. The secondary battery according to claim 7 , wherein:
the flow guiding component comprises an anode flow guiding component and a cathode flow guiding component, wherein the anode flow guiding component and the cathode flow guiding component are respectively located on two sides of the electrode assembly along the width direction;
at a cathode of the electrode assembly, each of the cathodic plates comprises a third end portion that extends beyond the anodic plates, and along the width direction, the third end portion is located between a first end portion and the anodic plates; and
a first thickness D 1 of the cathode flow guiding component satisfies D 1 ≤d 1 +d 2 ;
wherein d 1 is the distance between a first end portion and a connecting component corresponding thereto, and d 2 is a distance between the third end portion and a first end portion that is close to the third end portion.
9. The secondary battery according to claim 7 , wherein:
the flow guiding component comprises an anode flow guiding component and a cathode flow guiding component, wherein the anode flow guiding component and the cathode flow guiding component are respectively located on two sides of the electrode assembly along the width direction;
at an anode of the electrode assembly, each of the anodic plates comprises a second end portion that extends beyond the cathodic plates, and along the width direction, the second end portion is located between the cathodic plates and the first end portion; and
a second thickness D 2 of the anode flow guiding component satisfies D 2 ≤d 1 +d 3 ;
wherein d 1 is the distance between a first end portion and a connecting component corresponding thereto, and d 3 is a distance between the second end portion and a first end portion that is close to the second end portion.
10. The secondary battery according to claim 7 , wherein:
a thickness d of the flow guiding component satisfies a following formula:
d =( L 1 ×W 1 ×G−L 2 ×W 2 ×ρ 1 )/(ρ 2 ×H 3 ×( W 3 −1)) (1)
wherein L 1 is a total length of the anodic plates or a total length of the cathodic plates; W 1 is a width of an active material layer of the anodic plates or a width of an active material layer of the cathodic plates;
G is a distance between the anodic plates that are adjacent, or a distance between the cathodic plates that are adjacent;
L 2 is a total length of the separators; W 2 is a width of the separators;
H 3 is a height of the electrode assembly; W 3 is a width of the connecting components; and
ρ 1 is a liquid retention coefficient of the separators; ρ 2 is a liquid retention coefficient of the flow guiding component.
11. A battery pack, comprising: a secondary battery according to claim 1 .
12. An electric device, comprising: a secondary battery according to claim 1 , the secondary battery being used to provide electrical energy.