CN214957267U

CN214957267U - Laminated cell and laminated lithium battery

Info

Publication number: CN214957267U
Application number: CN202120442348.1U
Authority: CN
Inventors: 渠雁晓; 刘丰
Original assignee: Kunshan Bao Innovative Energy Technology Co Ltd
Current assignee: Kunshan Bao Innovative Energy Technology Co Ltd
Priority date: 2021-03-01
Filing date: 2021-03-01
Publication date: 2021-11-30
Anticipated expiration: 2031-03-01

Abstract

The utility model discloses a lamination formula electricity core and lamination formula lithium cell belongs to lithium cell technical field. A plurality of positive pole lugs form a plurality of groups of positive pole lug groups, and the positive pole lug groups of different groups are arranged in the circumferential direction of the cell body at intervals; when the positive pole lug group comprises more than two positive pole lugs, all the positive pole lugs in the positive pole lug group are positioned at the same position in the circumferential direction of the cell body; a plurality of negative pole lugs form a plurality of groups of negative pole lug groups, and the negative pole lug groups of different groups are arranged in the circumferential direction of the battery cell body at intervals; when the negative electrode lug group comprises more than two negative electrode lugs, all the negative electrode lugs in the negative electrode lug group are positioned at the same position in the circumferential direction of the battery cell body; the positive pole lug and the negative pole lug are distributed along the circumferential interval of the battery cell body, so that the risk of insufficient soldering is reduced, the phenomenon of short circuit of the battery cell is avoided, and the utilization rate of the internal space of the battery cell is improved.

Description

Laminated cell and laminated lithium battery

Technical Field

The utility model relates to a lithium cell technical field especially relates to a lamination formula electricity core and lamination formula lithium cell.

Background

The traditional laminated battery cell is manufactured by laminating a positive plate, a negative plate and a diaphragm, a positive tab and a negative tab are respectively welded on a connecting piece along the thickness direction of the laminated battery cell, and for a thicker battery cell, the risk of cold joint is easy to occur due to the mode of overlapping and welding a plurality of layers of tabs; and utmost point ear can buckle at the plastic in-process, and the accumulational phenomenon of utmost point ear appears easily in the region of buckling to multilayer utmost point ear, not only causes utmost point ear to stretch into inside the electric core easily, the phenomenon of short circuit appears, but also can be because multilayer utmost point ear superimposed thickness is thicker for the pole piece reduces along the length of the superimposed thickness direction after utmost point ear is buckled, has reduced electric core internal space utilization.

Therefore, a laminated battery cell and a laminated lithium battery that reduce the risk of cold joint, avoid short circuit, and improve the utilization rate of the internal space of the battery cell are needed to solve the above technical problems in the prior art.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a lamination formula electricity core and lamination formula lithium cell, this lamination formula electricity core and lamination formula lithium cell have reduced the risk of rosin joint, avoid electric core to take place the phenomenon of short circuit, and have improved the utilization ratio in electric core inner space.

To achieve the purpose, the utility model adopts the following technical proposal:

a laminated cell, comprising:

the battery cell comprises a battery cell body and a battery cell body, wherein the battery cell body comprises a plurality of positive pole pieces, a plurality of negative pole pieces and a diaphragm, and the positive pole pieces, the negative pole pieces and the diaphragm are stacked in a preset sequence along a first direction;

the positive electrode lugs are connected with the positive electrode plates in a one-to-one correspondence mode, the positive electrode lugs form multiple positive electrode lug groups, and the positive electrode lug groups in different groups are arranged in the circumferential direction of the battery cell body at intervals; when the positive pole lug group comprises more than two positive pole lugs, all the positive pole lugs in the positive pole lug group are located at the same position in the circumferential direction of the battery cell body;

the plurality of negative electrode lugs are connected with the plurality of negative electrode pole pieces in a one-to-one correspondence manner, the plurality of negative electrode lugs form a plurality of groups of negative electrode lug groups, and the negative electrode lug groups of different groups are arranged in the circumferential direction of the battery cell body at intervals; when the negative electrode lug group comprises more than two negative electrode lugs, all the negative electrode lugs in the negative electrode lug group are positioned at the same position in the circumferential direction of the battery cell body;

the positive electrode lug and the negative electrode lug are distributed at intervals along the circumferential direction of the battery cell body.

As a preferred technical scheme of a laminated battery cell, the length of the positive electrode tab is the sum of the bending distance of the positive electrode tab along the thickness direction of the battery cell body and the extension length of the positive electrode tab, and the extension lengths of all the positive electrode tabs are equal;

the length of the negative pole lug is the sum of the bending distance of the negative pole lug along the thickness direction of the battery cell body and the extension length of the negative pole lug, and the extension lengths of all the negative pole lugs are equal.

As a preferred technical scheme of the laminated battery cell, the positive electrode tab and the negative electrode tab are distributed on the same side of the battery cell body.

As a preferred technical scheme of the laminated battery cell, the positive electrode tab and the negative electrode tab are distributed at two ends of the battery cell body at the same side.

As an optimal technical scheme of a lamination formula electricity core, lamination formula electricity core still includes the connection piece, the quantity of electricity core body is two, two electricity core body stacks the setting, two when electricity core body stacks the setting anodal utmost point ear group with negative pole utmost point ear group's distribution mode is the same, the connection piece is connected two electricity core body anodal utmost point ear group or negative pole utmost point ear group.

As a preferred technical scheme of lamination formula electricity core, the connection piece includes first connecting portion, transition portion and second connecting portion, first connecting portion with the second connecting portion are located the both sides of transition portion, first connecting portion with the second connecting portion respectively with two of electric core body positive pole ear group or negative pole ear group connects.

As a preferred technical solution of the laminated cell, the thickness of the connecting sheet is not more than 1.5 mm.

As a preferred technical scheme of a lamination formula electricity core, the lamination formula electricity core still includes the apron, the apron lid is located the outside of connection piece.

As a preferred technical scheme of the laminated battery cell, the positive electrode tab and the positive electrode piece are integrally arranged; the negative pole lug and the negative pole piece are integrally arranged.

In order to achieve the above object, the utility model also provides a laminated lithium battery, including the aforesaid laminated electricity core.

The utility model provides a lamination formula electric core and lamination formula lithium cell, wherein, lamination formula lithium cell includes lamination formula electric core, lamination formula electric core includes the electric core body, a plurality of anodal utmost point ear and a plurality of negative pole utmost point ear, wherein, a plurality of anodal utmost point ear are connected with a plurality of anodal pole piece one-to-one, a plurality of negative pole utmost point ear are connected with a plurality of negative pole piece one-to-one, a plurality of anodal utmost point ears constitute multiunit anodal utmost point ear group, a plurality of negative pole utmost point ears constitute multiunit negative pole utmost point ear group, anodal utmost point ear group and negative pole utmost point ear group interval of different groups set up in the circumference of electric core body, through the arrangement anodal utmost point ear group and the negative pole utmost point ear group that misplace, every anodal utmost point ear group and the thickness of negative pole utmost point ear group have been thinned, the risk of anodal utmost point ear and negative pole utmost point ear in the anodal utmost point ear group in the welded in-welding process has been reduced; in the process that the positive electrode lugs and the negative electrode lugs in the positive electrode lug group and the negative electrode lug group are bent and shaped along the thickness direction of the cell body, the phenomenon that excessive positive electrode lugs and excessive negative electrode lugs are accumulated in a bending area is avoided, and further the risk of short circuit is avoided; the positive pole lug group and the negative pole lug group are arranged in a staggered mode, so that the thickness of the multi-layer pole lugs in a stacked mode is reduced, the length of the pole piece in the stacked thickness direction after the pole lugs are bent is increased, and the utilization rate of the internal space of the battery core is improved.

Drawings

Fig. 1 is a schematic structural diagram of a battery cell body, two sets of positive electrode tab sets and two sets of negative electrode tab sets according to an embodiment of the present invention;

fig. 2 is a top view of a battery cell body, two sets of positive electrode tab sets and two sets of negative electrode tab sets according to an embodiment of the present invention;

fig. 3 is a front view of a battery cell body, two sets of positive electrode tab sets and two sets of negative electrode tab sets according to an embodiment of the present invention;

fig. 4 is a side view of the battery cell body, two sets of positive electrode tab sets and two sets of negative electrode tab sets according to the embodiment of the present invention;

fig. 5 is a schematic structural view of two sets of positive electrode tab sets and two sets of negative electrode tab sets on the battery cell body after bending and shaping according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a two-pole stack laminated electrical core provided in an embodiment of the present invention before core assembly;

fig. 7 is a top view of a two-pole stack laminated electrical core provided in an embodiment of the present invention before core assembly;

fig. 8 is a side view of a two-pole stack laminated electrical core provided in an embodiment of the present invention before core assembly;

fig. 9 is an exploded view of a two-pole stack laminated cell according to an embodiment of the present invention;

FIG. 10 is a schematic structural view of a connecting sheet according to an embodiment of the present invention;

fig. 11 is a schematic structural view of three groups of positive electrode tab groups and three groups of negative electrode tab groups on the battery cell body after bending and shaping;

fig. 12 is a schematic structural diagram of connection between three sets of positive electrode tab sets and three sets of negative electrode tab sets of the battery cell body and a connecting sheet according to an embodiment of the present invention;

fig. 13 is a schematic structural diagram of another two-electrode stack laminated electrical core before core combination according to an embodiment of the present invention.

Reference numerals:

1. a cell body; 2. a positive electrode tab; 3. a negative electrode tab;

4. connecting sheets; 41. a first connection portion; 42. a transition section; 43. a second connecting portion;

5. and (7) a cover plate.

Detailed Description

In order to make the technical problem solved by the present invention, the technical solution adopted by the present invention and the technical effect achieved by the present invention clearer, the technical solution of the present invention will be further explained by combining the drawings and by means of the specific implementation manner.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, detachably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact between the first and second features, or may comprise contact between the first and second features not directly. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are used in the orientation or positional relationship shown in the drawings only for convenience of description and simplicity of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.

As shown in fig. 1 to 5 and 11, the present embodiment provides a laminated electrical core, which includes an electrical core body 1, a plurality of positive electrode tabs 2, and a plurality of negative electrode tabs 3, where the electrical core body 1 includes a plurality of positive electrode plates, a plurality of negative electrode plates, and a diaphragm, and the positive electrode plates, the negative electrode plates, and the diaphragm are stacked in a preset order along a first direction; the positive electrode lugs 2 are connected with the positive electrode plates in a one-to-one correspondence manner, the positive electrode lugs 2 form a plurality of positive electrode lug groups, and the positive electrode lug groups of different groups are arranged in the circumferential direction of the cell body 1 at intervals; when the positive pole lug group comprises more than two positive pole lugs 2, all the positive pole lugs 2 in the positive pole lug group are positioned at the same position in the circumferential direction of the battery cell body 1; the plurality of negative electrode lugs 3 are connected with the plurality of negative electrode pole pieces in a one-to-one correspondence manner, the plurality of negative electrode lugs 3 form a plurality of groups of negative electrode lug groups, and the negative electrode lug groups of different groups are arranged in the circumferential direction of the battery cell body 1 at intervals; when the negative electrode lug group comprises more than two negative electrode lugs 3, all the negative electrode lugs 3 in the negative electrode lug group are positioned at the same position in the circumferential direction of the battery cell body 1; the positive electrode lug 2 and the negative electrode lug 3 are distributed at intervals along the circumferential direction of the cell body 1.

The positive pole lug groups and the negative pole lug groups are arranged in a staggered manner, so that the thickness of each positive pole lug group and each negative pole lug group is reduced, and the risk of insufficient welding of the positive pole lugs 2 and the negative pole lugs 3 in the positive pole lug groups and the negative pole lug groups in the welding process is reduced; in the process that the positive electrode tabs 2 and the negative electrode tabs 3 in the positive electrode tab group and the negative electrode tab group are bent and shaped along the thickness direction of the cell body 1, the phenomenon that excessive positive electrode tabs 2 and negative electrode tabs 3 are accumulated in a bent area is avoided, and further the risk of short circuit is avoided; because the utmost point ear number of piles is thicker, and utmost point ear piles up more seriously, consequently need reserve sufficient space when the design, in this embodiment, with anodal utmost point ear group and negative pole utmost point ear group arrangement by mistake to reduce multilayer utmost point ear superimposed thickness, increased the length of pole piece along the superimposed thickness direction after utmost point ear is buckled, improved electric core inner space's utilization ratio.

It should be noted that, because the multiple positive electrode tabs 2 and the multiple negative electrode tabs 3 in this embodiment respectively constitute multiple sets of positive electrode tab groups and multiple sets of negative electrode tab groups, the multiple sets of positive electrode tab groups and the multiple sets of negative electrode tab groups are arranged in a staggered manner, so that the number of the tabs in each positive electrode tab group and each negative electrode tab group is reduced, the thickness is reduced, thereby in the welding process, under the condition of ensuring the welding strength, the width of the tabs is reduced, thereby the material consumption of the tabs is reduced, and the material cost is reduced.

Preferably, in this embodiment, a plurality of positive pole pieces, a plurality of negative pole pieces and diaphragm are once piled up, reduce the space that the diaphragm occupies, increase the pole piece number of piles, promote electric core capacity. It should be noted that, a diaphragm can be folded for several times to form an M shape extending repeatedly, the positive pole piece and the negative pole piece are parallel, and are sequentially inserted into the diaphragm at intervals to be stacked alternately, and the M shape is extended repeatedly according to the manner of negative pole piece-diaphragm-positive pole piece-diaphragm-negative pole piece; or a plurality of diaphragms, a plurality of positive pole pieces and a plurality of negative pole pieces are repeatedly overlapped and extended in a negative pole piece-diaphragm-positive pole piece-diaphragm-negative pole piece mode.

Preferably, as shown in fig. 5 and 11, the length of the positive electrode tab 2 is the sum of the bending distance of the positive electrode tab 2 along the thickness direction of the cell body 1 and the extension length of the positive electrode tab 2, and the extension lengths of all the positive electrode tabs 2 are equal; the length of the negative electrode tab 3 is the sum of the bending distance of the negative electrode tab 3 along the thickness direction of the cell body 1 and the extension length of the negative electrode tab 3, and the extension lengths of all the negative electrode tabs 3 are equal. The extending lengths of all the anode tabs 2 or all the cathode tabs 3 are equal after bending and shaping; compared with the case that the lengths of all the positive electrode tabs 2 or all the negative electrode tabs 3 are set to be the same, the material usage amount of the positive electrode tabs 2 and the negative electrode tabs 3 is reduced, and the cost is reduced. Preferably, in the present embodiment, the protruding length of the cathode tab 2 and the protruding length of the anode tab 3 are equal.

Preferably, as shown in fig. 1, positive pole lug 2 and negative pole lug 3 distribute in the homonymy of electricity core body 1, and the convenience is divided into four utmost point groups or two utmost points group back with electric core in thick electric core, buckles the plastic to positive pole lug group and negative pole lug group of every utmost point group respectively for positive pole lug group and negative pole lug group of the relative utmost point group that sets up correspond and connect, close the core to the relative utmost point group that sets up again. The electrode group refers to the cell body 1 to which the positive electrode tab 2 and the negative electrode tab 3 are connected. In this embodiment, the positive electrode tab 2 and the negative electrode tab 3 are distributed at two ends of the same side of the battery cell body 1, so that the positive electrode tab group or the negative electrode tab group at the same side can be connected together.

It should be noted that dividing the battery cell into four electrode groups is more complicated than dividing the battery cell into two electrode groups, and the number of layers of the separator is increased due to the increase of the number of the electrode groups, so that the number of layers of the pole piece is also reduced, and partial capacity loss is caused.

As shown in fig. 6 to 9, 12, and 13, in this embodiment, the laminated battery cell further includes a connecting sheet 4, the number of the battery cell bodies 1 is two, two battery cell bodies 1 are stacked, and the distribution modes of the positive electrode tab group and the negative electrode tab group when the two battery cell bodies 1 are stacked are the same, so that the positive electrode tab group and the negative electrode tab group of the two battery cell bodies 1 along the circumferential direction thereof are located at the same position, and the connecting sheet 4 connects the positive electrode tab group or the negative electrode tab group of the two battery cell bodies 1. In the embodiment, the arrangement mode of staggered, layered and misaligned lugs is adopted, and the welding qualification rate of the lugs and the connecting sheets 4 can be improved for thick cells.

Specifically, as shown in fig. 10, the connecting sheet 4 includes a first connecting portion 41, a transition portion 42, and a second connecting portion 43, the first connecting portion 41 and the second connecting portion 43 are partially disposed on two sides of the transition portion 42, and the first connecting portion 41 and the second connecting portion 43 are respectively connected to the positive electrode tab group or the negative electrode tab group of the two cell bodies 1. Preferably, in the present embodiment, the first connecting portion 41, the transition portion 42 and the second connecting portion 43 form an i-shaped structure. Alternatively, in other embodiments, the connecting piece 4 may have any other shape. Preferably, in this embodiment, the thickness of the connecting piece 4 is not more than 1.5 mm. It should be noted that the lengths of the first connecting portion 41 and the second connecting portion 43 need to be lengthened appropriately as the number of the positive electrode tab group and the negative electrode tab group increases, and the specific length of the lengthening is adjusted according to actual conditions, so as to ensure the connection strength between the connecting piece 4 and the tab.

Further, in this embodiment, the positive electrode tab group and the negative electrode tab group connected to the two battery cell bodies 1 are symmetrical with respect to the central line of the connecting sheet 4, and when the two battery cell bodies 1 close to each other, the two battery cell bodies 1 are attached to each other on the plane.

Further, as shown in fig. 6 to 9, 12 and 13, the laminated battery core further includes a cover plate 5, and the cover plate 5 covers the connecting piece 4.

Preferably, the positive pole tab 2 and the positive pole piece are integrally arranged; the negative pole tab 3 and the negative pole piece are integrally arranged. Specifically, in the process of processing the positive pole piece and the negative pole piece, a foil exposing area which is not coated with an active substance coating is reserved at a preset position of the end parts of the positive pole foil and the negative pole foil, and the foil exposing area forms a positive pole lug 2 and a negative pole lug 3.

Exemplarily, as shown in fig. 1 to 5, the plurality of positive electrode tabs 2 include two sets of positive electrode tab groups, the two sets of positive electrode tab groups do not have an overlapping region, the length of the positive electrode tab 2 of one of the two sets of positive electrode tab groups is longer, and the length of the positive electrode tab 2 of the other set is shorter, so as to ensure that the extension lengths of the positive electrode tabs 2 in the two sets of positive electrode tab groups after bending and shaping are the same; a plurality of negative pole utmost point ears 3 include two sets of negative pole ear groups, and there is not the coincidence zone two sets of negative pole ear groups, and wherein 3 lengths of a set of negative pole utmost point ear are longer in two sets of negative pole ear groups, and 3 lengths of another set of negative pole utmost point ear are shorter to guarantee that 3 stretches out the length after the plastic of buckling of negative pole utmost point ear in two sets of negative pole ear groups are the same. As shown in fig. 6 to 9, the number of the cell bodies 1 is two, the distribution form of the positive electrode lug groups and the negative electrode lug groups on the two cell bodies 1 is centrosymmetric, the positive electrode lug group on one of the two cell bodies 1 is welded to the first connecting portion 41 of the connecting sheet 4 to realize electrical connection, the positive electrode lug group on the other cell body is welded to the second connecting portion 43 of the connecting sheet 4 to realize electrical connection, and the transition portion 42 is welded to the terminal bottom plate of the cover plate 5 to realize electrical connection; similarly, the negative electrode tab group on one of the two cell bodies 1 is welded to the first connection portion 41 of the connection piece 4 to realize electrical connection, the negative electrode tab group on the other one is welded to the second connection portion 43 of the connection piece 4 to realize electrical connection, and the transition portion 42 is welded to the terminal bottom plate of the cover plate 5 to realize electrical connection. After the operation is finished, the two battery cell bodies 1 are combined. The assembly mode of the two pole sets is adopted, the assembly efficiency is effectively improved, and the production cost is reduced.

For example, as shown in fig. 11 to 13, the positive electrode tabs 2 include three positive electrode tab groups, and the negative electrode tabs 3 include three negative electrode tab groups, and the connection manner is the same as that of the two positive electrode tab groups and that of the two negative electrode tab groups, which is not described herein again.

The embodiment also provides a manufacturing method of the laminated battery cell, which is used for manufacturing the laminated battery cell, and the manufacturing method of the laminated battery cell includes:

step S1, connecting a plurality of positive pole tabs 2 with a plurality of positive pole pieces in a one-to-one correspondence manner; connecting a plurality of negative electrode tabs 3 with a plurality of negative electrode pole pieces in a one-to-one correspondence manner;

preferably, in the present embodiment, the positive electrode tab 2 and the positive electrode tab are integrally formed, and the negative electrode tab 3 and the negative electrode tab are integrally formed.

Step S2, overlapping a plurality of positive pole pieces connected with positive pole lugs 2, a plurality of negative pole pieces connected with negative pole lugs 3 and diaphragms in a preset sequence along a first direction, wherein the positive pole pieces, the negative pole pieces and the diaphragms form a cell body 1, the positive pole lugs 2 located at the same position in the circumferential direction of the cell body 1 form a positive pole lug group, and the negative pole lugs 3 located at the same position in the circumferential direction of the cell body 1 form a negative pole lug group;

step S3, bending and shaping the positive electrode tabs 2 in the positive electrode tab group along the thickness direction of the cell body 1 so as to connect all the positive electrode tabs 2 in the positive electrode tab group into a whole; and bending and shaping the negative electrode tab 3 in the negative electrode tab group along the thickness direction of the battery core body 1 so as to connect all the negative electrode tabs 3 in the negative electrode tab group into a whole. Preferably, the positive pole lug group can be pre-welded after being bent and shaped; the negative pole lug group can be pre-welded after being bent and shaped.

The embodiment also provides a laminated lithium battery, which comprises the laminated battery core.

The above description is only for the preferred embodiment of the present invention, and for those skilled in the art, there are variations on the detailed description and the application scope according to the idea of the present invention, and the content of the description should not be construed as a limitation to the present invention.

Claims

1. A laminated cell, comprising:

the battery cell comprises a battery cell body (1) and a battery cell body, wherein the battery cell body comprises a plurality of positive pole pieces, a plurality of negative pole pieces and a diaphragm, and the positive pole pieces, the negative pole pieces and the diaphragm are arranged in a superposed mode along a first direction in a preset sequence;

the positive electrode lugs (2) are connected with the positive electrode plates in a one-to-one correspondence mode, the positive electrode lugs (2) form a plurality of positive electrode lug groups, and the positive electrode lug groups in different groups are arranged in the circumferential direction of the battery cell body (1) at intervals; when the positive pole lug group comprises more than two positive pole lugs (2), all the positive pole lugs (2) in the positive pole lug group are located at the same position in the circumferential direction of the battery cell body (1);

the negative electrode tabs (3) are connected with the negative electrode pole pieces in a one-to-one correspondence mode, the negative electrode tabs (3) form a plurality of groups of negative electrode tab groups, and the negative electrode tab groups in different groups are arranged in the circumferential direction of the battery cell body (1) at intervals; when the negative electrode lug group comprises more than two negative electrode lugs (3), all the negative electrode lugs (3) in the negative electrode lug group are positioned at the same position in the circumferential direction of the battery cell body (1);

the positive electrode lug (2) and the negative electrode lug (3) are distributed at intervals along the circumferential direction of the battery cell body (1).

2. The laminated cell of claim 1, wherein the length of the positive electrode tab (2) is the sum of the bending distance of the positive electrode tab (2) in the thickness direction of the cell body (1) and the extension length of the positive electrode tab (2), and the extension lengths of all the positive electrode tabs (2) are equal;

the length of the negative pole lug (3) is the sum of the bending distance of the negative pole lug (3) along the thickness direction of the battery cell body (1) and the extension length of the negative pole lug (3), and the extension lengths of all the negative pole lugs (3) are equal.

3. The laminated cell of claim 1 or 2, characterized in that the positive electrode tab (2) and the negative electrode tab (3) are distributed on the same side of the cell body (1).

4. The laminated cell according to claim 3, wherein the positive electrode tab (2) and the negative electrode tab (3) are distributed at both ends of the cell body (1) on the same side.

5. The laminated battery cell according to claim 4, wherein the laminated battery cell further comprises a connecting sheet (4), the number of the battery cell bodies (1) is two, two battery cell bodies (1) are stacked, the distribution of the positive electrode tab group and the negative electrode tab group when the two battery cell bodies (1) are stacked is the same, and the connecting sheet (4) connects the positive electrode tab group or the negative electrode tab group of the two battery cell bodies (1).

6. The laminated cell of claim 5, wherein the connecting sheet (4) comprises a first connecting portion (41), a transition portion (42) and a second connecting portion (43), the first connecting portion (41) and the second connecting portion (43) are respectively disposed on two sides of the transition portion (42), and the first connecting portion (41) and the second connecting portion (43) are respectively connected with the positive pole lug group or the negative pole lug group of the two cell bodies (1).

7. The laminated cell of claim 5, characterized in that the thickness of the connecting web (4) is not more than 1.5 mm.

8. The laminated cell of claim 5, further comprising a cover plate (5), wherein the cover plate (5) covers the connecting sheet (4).

9. The laminated cell according to claim 1, characterised in that the positive tab (2) and the positive pole piece are provided in one piece; the negative pole tab (3) and the negative pole piece are integrally arranged.

10. A laminated lithium battery comprising a laminated cell according to any of claims 1 to 9.