Lithium battery and manufacturing method thereof

1. A lithium battery, comprising a battery shell and a battery cell;

the battery cell comprising:

a plurality of laminated plate sets, each plate set being formed by laminating a positive plate, a separator and a negative plate; and the positive plate being provided with a positive tab extending outwardly along the plate, and the negative plate being provided with a negative tab extending outwardly along the plate, wherein,

the positive tab is composed of a straight section extending outwardly along the positive plate and a positive tab bend; and/or, the negative tab is composed of a straight section extending outwardly along the negative plate and a negative tab bend;

a plurality of positive tab bends of the plurality of plate sets are laminated to form a bent book page-shaped structure, a stress exists between adjacent positive tab bends in the bent book page-shaped structure, and the bent book page-shaped structure forms a stressed entirety under actions of the stress and an elastic force generated by deformation of the plurality of positive tabs;

and/or, a plurality of negative tab bends of the plurality of plate sets are laminated to form a bent book page-shaped structure, a stress exists between adjacent negative tab bends in the bent book page-shaped structure, and the bent book page-shaped structure forms a stressed entirety under actions of the stress and an elastic force generated by deformation of the plurality of negative tabs;

after the plurality of plate sets are clamped on a converging device, two converging devices are respectively clamped at the positive and negative tabs, the tabs are subjected to mould pressing on outer sides the converging devices to realize preset bending, the positive and negative tabs are welded to an end face connector to form a convergence, and then quickly enter the shell to be welded to an end cover;

the converging device is a C-shaped clamping position or a U-shaped clamping position; the C-shaped clamping position comprises two clamping plates capable of moving vertically; and the U-shaped clamping position comprises two clamping plates capable of moving horizontally; and

when a coordinate system is established along a length direction of a tab as an x axis and a direction perpendicular to the tab as a y axis, and a projection contour line of a curved surface on which the tab is located on an xy plane is represented by y=f(x),

a length of a bent part of the tab is calculated by the following formula:

L

=

∫

a

b

1

+

(

f

′

(

x

)

)

2

⁢

dx

wherein upper and lower limits a and b of the integral represent a value range of the x axis of the contour line of the tab.

2. The lithium battery according to claim 1 , wherein:

the bent book page-shaped structures formed by laminating the plurality of positive tab bends and/or negative tab bends have opposite bending directions; or

the bent book page-shaped structures formed by laminating the plurality of positive tab bends and/or negative tab bends have the same bending direction.

3. The lithium battery according to claim 1 , wherein the positive tab bend and/or the negative tab bend has a structure of bending upwardly along a direction of the plate to reach a vertex, then bending downwardly and passing through a plane on which the plate is located to extend.

4. A manufacturing method of a lithium battery, comprising:

laminating to form a plurality of plate sets, wherein each plate set is formed by laminating a positive plate, a separator and a negative plate; and the positive plate is provided with a positive tab extending outwardly along the plate, and the negative plate is provided with a negative tab extending outwardly along the plate,

after the plurality of plate sets are clamped on a converging device, two converging devices are respectively clamped at the positive and negative tabs, the tabs are subjected to mould pressing on outer sides the converging devices to realize preset bending, the positive and negative tabs are welded to an end face connector to form a convergence, and then quickly enter the shell to be welded to an end cover;

the converging device is a C-shaped clamping position or a U-shaped clamping position; the C-shaped clamping position comprises two clamping plates capable of moving vertically; and the U-shaped clamping position comprises two clamping plates capable of moving horizontally;

when a coordinate system is established along a length direction of the tab as an x axis and a direction perpendicular to the tab as a y axis, and a projection contour line of a curved surface on which the tab is located on an xy plane is represented by y=f(x),

then a length of a bent part of the tab is calculated by the following formula:

L

=

∫

a

b

1

+

(

f

′

(

x

)

)

2

⁢

dx

wherein upper and lower limits a and b of the integral represent a value range of the x axis of the contour line of the tab;

the positive tab is composed of a straight section extending outwardly along the positive plate and a positive tab bend; and/or, the negative tab is composed of a straight section extending outwardly along the negative plate and a negative tab bend; and

a plurality of positive tab bends of the plurality of plate sets are laminated to form a bent book page-shaped structure, a stress exists between adjacent positive tab bends in the bent book page-shaped structure, and the bent book page-shaped structure forms a stressed entirety under actions of the stress and an elastic force generated by deformation of the plurality of positive tabs;

and/or, a plurality of negative tab bends of the plurality of plate sets are laminated to form a bent book page-shaped structure, a stress exists between adjacent negative tab bends in the bent book page-shaped structure, and the bent book page-shaped structure forms a stressed entirety under actions of the stress and an elastic force generated by deformation of the plurality of negative tabs.

5. The method according to claim 4 , comprising:

bending the plurality of positive tab bends and negative tab bends in the same direction;

or, bending the plurality of positive tab bends and negative tab bends in opposite directions.

6. The lithium battery according to claim 2 , wherein:

each of the plurality of laminated plate sets is formed by laminating a positive plate, a separator, and a negative plate;

overlapped parts of the positive plate and the negative plate is insulated by the separator, and non-overlapped parts of the positive plate and the negative plate form the positive tab and the negative tab;

the positive tab is composed of the straight section extending outwardly along the positive plate and the positive tab bend; the negative tab is composed of the straight section extending outwardly along the negative plate and the negative tab bend;

wherein the positive tab bend and the negative tab bend have opposite bending directions, and both the positive tab bend and the negative tab bend are bent towards the separator located between the positive plate and the negative plate.

7. The method according to claim 5 , wherein:

each of the plurality of laminated plate sets is formed by laminating a positive plate, a separator, and a negative plate;

overlapped parts of the positive plate and the negative plate is insulated by the separator, and non-overlapped parts of the positive plate and the negative plate form the positive tab and the negative tab;

the positive tab is composed of the straight section extending outwardly along the positive plate and the positive tab bend; the negative tab is composed of the straight section extending outwardly along the negative plate and the negative tab bend;

wherein the positive tab bend and the negative tab bend have opposite bending directions, and both the positive tab bend and the negative tab bend are bent towards the separator located between the positive plate and the negative plate.