CN220672807U - Folded tab structure of multi-tab battery cell and lithium battery - Google Patents

Abstract

The utility model discloses a folded tab structure of a multi-tab battery cell, which belongs to the technical field of lithium batteries and comprises a battery cell body, a foil tab and a switching tab; the foil lugs with the same polarity are provided with a plurality of foil lugs which are mutually overlapped to form a multi-layer structure, and the multi-layer structure comprises an odd layer and an even layer; the foil electrode lugs are of long sheet structures, the lengths of the foil electrode lugs of odd layers are sequentially increased along the thickness direction of the multilayer structure, and the lengths of the foil electrode lugs of even layers are sequentially increased along the thickness direction of the multilayer structure; welding a plurality of foil lugs which are arranged in an overlapping manner and have the same polarity to form a pre-welding area and a final welding area, wherein in the pre-welding area, all foil lugs of an odd layer and an even layer are contacted with each other, and in the final welding area, only foil lugs of the odd layer or the even layer are contacted with each other; the switching tab is connected with the foil tab of the final welding area. The utility model solves the problem that the bending structure of the multipole in the existing multipole cell occupies too much space.

Description

Folded tab structure of multi-tab battery cell and lithium battery

Technical Field

The utility model relates to the technical field of lithium batteries, in particular to a folded tab structure of a multi-tab battery cell and a lithium battery.

Background

For lithium battery cells with multi-pole ear structures, such as battery cells of soft-package lithium batteries and steel-shell batteries, most of the lithium battery cells adopt a winding structure, each circle of pole piece in the winding structure is led out of a foil pole ear, extends to one end of the battery cell and is overlapped with the foil pole ear; before packaging the battery core, shaping and welding a plurality of foil tabs which are overlapped with each other into a whole, then welding the whole with the metal strip tabs which are connected with each other, and then bending the whole, so that the battery core can be packaged in a shell.

The multipolar lug connection structure has the advantages of high charging rate, good high-low temperature discharging effect, capability of reducing the internal resistance of the battery, reduction of temperature rise in the charging process and the like.

For example, chinese patent document CN111403789B discloses an electrode assembly and a battery, wherein the electrode assembly includes a first electrode sheet, a second electrode sheet, and a separator disposed between the first electrode sheet and the second electrode sheet, and the first electrode sheet and the second electrode sheet are wound or overlapped to form the electrode assembly; wherein the electrode assembly further comprises: the first tab is arranged on the first pole piece; the insulation layer comprises a first part arranged on the first pole piece, and no second pole piece is arranged between the first part and the first pole lug; when the first pole piece and the second pole piece are wound to form the electrode assembly, the first pole lug comprises a plurality of first pole lug units, and the plurality of first pole lug units comprise an innermost first pole lug unit close to the insulating layer; and the second pole piece is not arranged between the insulating layer and the innermost first pole ear unit. The electrode assembly is a typical structure in which the whole multipolar lug is welded with the switched lug and then bent.

However, the multipolar ear connection structure similar to the above-described electrode assembly has the following drawbacks: the thickness of a plurality of foil tabs after overlapping and welding is very big, and then the thickness of the foil tabs after welding with the metal strip tabs of switching is bigger, so that the connecting area of the foil tabs and the metal strip tabs after bending occupies a very large space, and the battery core needs to be provided with a very large accommodating space after packaging, thereby occupying the space of an active area in a phase-changing manner, and being unfavorable for improving the energy density of the battery.

In view of this, there is a need for improvements in the structure of existing multi-pole cells.

Disclosure of Invention

Aiming at the defects of the prior art, the utility model provides a folded tab structure of a multi-tab cell and a lithium battery, so as to solve the problem that the space occupied by the folded tab structure of the existing multi-tab cell is overlarge, thereby providing more space for an active area and improving the energy density of the battery.

The utility model discloses a folded tab structure of a multi-tab battery cell, which comprises a battery cell body, a foil tab connected to the battery cell body and a switching tab; the foil tab comprises a positive foil tab and a negative foil tab, wherein a plurality of foil tabs with the same polarity are arranged and mutually overlapped to form a multilayer structure, and the multilayer structure comprises an odd layer and an even layer; the foil electrode lugs are of long sheet structures, the lengths of the foil electrode lugs of odd layers are sequentially increased along the thickness direction of the multilayer structure, and the lengths of the foil electrode lugs of even layers are sequentially increased along the thickness direction of the multilayer structure; a plurality of foil tabs which are arranged in an overlapping manner and have the same polarity are welded with each other to form a pre-welding area and a final welding area, wherein in the pre-welding area, all foil tabs of an odd layer and an even layer are contacted with each other, and in the final welding area, only foil tabs of the odd layer or the even layer are contacted with each other; the switching tab is connected with the foil tab of the final welding area.

Preferably, the length of the foil tab located at the even layer is smaller than the length of the foil tab located at the previous odd layer adjacent to the foil tab, and the length of the foil tab located at the first even layer is the smallest; in the final welding area, only the foil lugs of the odd layers are contacted with each other.

Preferably, the length of the foil tab in the odd layer is smaller than the length of the foil tab in the previous even layer adjacent to the foil tab, and the length of the foil tab in the first odd layer is the smallest; in the final welding area, only even layers of foil lugs are contacted with each other.

Preferably, the lengths of the plurality of foil tabs of the odd layers are in an arithmetic progression, and the lengths of the plurality of foil tabs of the even layers are in an arithmetic progression.

Preferably, the tolerance of the length of the foil tabs of the odd layers is the same as the tolerance of the length of the foil tabs of the even layers.

Preferably, the electric core body is provided with a connecting end face, and the foil tab with the same polarity is arranged on the same connecting end face of the electric core body.

Preferably, the foil tab of the final welding area forms a bending structure relative to the foil tab of the pre-welding area, and the bending direction of the final welding area faces the connecting end face.

Preferably, the transfer tab is connected to a surface of the final welding area facing the connection end face.

Preferably, the transfer tab is connected to a surface of the final welding area facing away from the connection end face.

The utility model discloses a lithium battery, which comprises a folded tab structure of any multi-tab battery core.

The utility model has the beneficial effects that:

by adopting the foil lugs with different lengths of the odd layers and the even layers and increasing progressively in sequence, all the foil lugs of the odd layers and the even layers are in welding contact with each other in the pre-welding area, and only the foil lugs of the odd layers or the even layers are in welding contact with each other in the final welding area, so that the thickness of the multipolar lug structure of the final welding area is greatly reduced, the occupied space after the multipolar lug structure of the final welding area is welded and bent with the switching lug is greatly reduced on the premise of not weakening the current carrying capacity of the lug, the problem that the bending structure of the multipolar lug occupies too much space in the conventional multipolar lug battery is solved, more space is provided for the active area of the battery, and the energy density of the battery is improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute an undue limitation to the application. In the drawings:

fig. 1 is a schematic length diagram of a foil tab in example 1 and example 3;

fig. 2 is a schematic length diagram of the foil tab in example 2 and example 4;

FIG. 3 is a schematic overall structure of embodiment 1;

FIG. 4 is a schematic overall structure of embodiment 2;

FIG. 5 is a schematic overall structure of embodiment 3;

fig. 6 is a schematic overall structure of embodiment 4.

Reference numerals illustrate: 1. a cell body; 101. a main side; 102. a connecting end face; 2. foil tab; 201. a pre-welding area; 202. a final welding area; 203. a bending part; 3. and (5) switching the electrode lugs.

Detailed Description

Various embodiments of the utility model are disclosed in the following drawings, in which details of the practice are set forth in the following description for the purpose of clarity. However, it should be understood that these practical details are not to be taken as limiting the utility model. That is, in some embodiments of the utility model, these practical details are unnecessary. Moreover, for the sake of simplicity of the drawing, some well-known and conventional structures and elements are shown in the drawings in a simplified schematic manner.

It should be noted that all directional indications such as up, down, left, right, front, and rear … … in the embodiments of the present utility model are merely used to explain the relative positional relationship, movement, etc. between the components in a particular posture such as that shown in the drawings, and if the particular posture is changed, the directional indication is changed accordingly.

In addition, the descriptions of the "first", "second", etc. in this application are for descriptive purposes only and are not intended to specifically indicate a sequential or a cis-position, nor are they intended to limit the utility model, but are merely intended to distinguish between components or operations described in the same technical term, and are not to be construed as indicating or implying a relative importance or implying that the number of technical features indicated is not necessarily limited. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present utility model.

For a further understanding of the utility model, its features and advantages, reference is now made to the following examples, which are illustrated in the accompanying drawings in which:

example 1

Referring to fig. 1 and 3, in order to disclose a folded tab structure of a multi-tab battery cell according to this embodiment, the folded tab structure includes a battery cell body 1, a foil tab 2 and a switching tab 3, wherein the battery cell body 1 is a flat structure, and has two opposite main sides 101 and two opposite connection end faces 102, the battery cell body 1 includes a pole piece and a diaphragm (both not shown in the figure), and the pole piece and the diaphragm are manufactured into the battery cell body 1 through a winding process.

Referring to fig. 1 and 3, the pole pieces include a positive pole piece and a negative pole piece, each pole piece is connected with the foil tab 2, the foil tab 2 is of a long sheet structure, the foil tab 2 connected with the positive pole piece is used as the positive foil tab 2, the foil tab 2 connected with the negative pole piece is used as the negative foil tab 2, the foil tab 2 of the same polarity extends out from the same connection end face 102 of the battery core body 1, and the foil tabs 2 of the same polarity are mutually overlapped along the direction perpendicular to the main side face 101 to form a multilayer structure.

Referring to fig. 1 and 3, the multi-layer structure formed by the plurality of foil tabs 2 of the same polarity from one main side 101 to the other main side 101 of the battery body 1 includes an odd layer and an even layer, the length of the foil tab 2 is the dimension of the foil tab 2 in the direction perpendicular to the connection end face 102, in this embodiment, the lengths of the plurality of foil tabs 2 of the odd layer sequentially increase from the one main side 101 to the other main side 101, the lengths of the plurality of foil tabs 2 of the even layer also sequentially increase in the same direction, and the length of the foil tab 2 of the even layer is smaller than the length of the foil tab 2 of the previous odd layer adjacent thereto, and the length of the foil tab 2 of the first even layer is the smallest; the lengths of the foil tabs 2 of the odd layers are in an arithmetic series, the lengths of the foil tabs 2 of the even layers are also in an arithmetic series, and the length tolerance of the foil tabs 2 of the odd layers is the same as the length tolerance of the foil tabs 2 of the even layers.

Referring to fig. 1 and 3, a plurality of overlapped foil tabs 2 of the same polarity are formed into a multi-tab structure by welding and shaping, in the multi-tab structure, a region where the foil tabs 2 are welded to each other includes a pre-welding region 201 and a final welding region 202, in the pre-welding region 201, all the foil tabs 2 of odd and even layers are in contact with each other, and in the final welding region 202, only all the foil tabs 2 of odd layers are in contact with each other, so that the thickness of the multi-tab structure of the final welding region 202 is only half of the thickness of the multi-tab structure of the pre-welding region 201; the transfer tab 3 is a metal strip structure, the multi-tab structure formed by the foil tab 2 located in the final welding area 202 and the transfer tab 3 are welded to each other, the foil tab 2 of the final welding area 202 forms a bending structure relative to the foil tab 2 of the pre-welding area 201, the bending direction faces the connection end face 102 of the battery cell body 1, the junction position between the final welding area 202 and the pre-welding area 201 is a bending part 203, and in this embodiment, the transfer tab 3 is welded on the surface of the final welding area 202 facing the connection end face 102.

Example 2

Referring to fig. 2 and 4, the difference between the present embodiment and embodiment 1 is that the length of the foil tab 2 located at the odd layer is smaller than the length of the foil tab 2 located at the previous even layer adjacent thereto, and the length of the foil tab 2 located at the first odd layer is the smallest; in addition, in the final bonding area 202, only all the foil tabs 2 of even layers are in contact with each other.

Example 3

Referring to fig. 1 and 5, the difference between the present embodiment and embodiment 1 is that the switching tab 3 is welded on the surface of the final welding area 202 facing away from the connection end face 102.

Example 4

Referring to fig. 2 and 6, the difference between the present embodiment and embodiment 2 is that the switching tab 3 is welded on the surface of the final welding area 202 facing away from the connection end face 102.

Example 5

The difference between this embodiment and embodiment 1 is that the cell body 1 is a cylindrical structure, the outer circumferential surface of the cell body 1 is a main side 101, two end surfaces of the cylindrical structure are connection end surfaces 102, a plurality of foil tabs 2 with the same polarity are overlapped with each other along the radial direction of the cell body 1, in the multi-layer structure formed by the foil tabs 2, the odd number layer and the even number layer count along the overlapping direction, the increment direction of the length of the odd number layer foil tab 2 is the same as the increment direction of the length of the even number layer foil tab 2, and both are the same direction along the radial direction.

The utility model also discloses a lithium battery, which comprises the folded tab structure of the multi-tab battery cell in any one of embodiments 1-5.

The implementation principle and the beneficial effects of the utility model are that by adopting the foil tabs 2 with different lengths of the odd layers and the even layers and increasing gradually, all the foil tabs 2 of the odd layers and the even layers are in welding contact with each other in the pre-welding area 201, and only the foil tabs 2 of the odd layers or the even layers are in welding contact with each other in the final welding area 202, thereby greatly reducing the thickness of the multi-tab structure of the final welding area 202, greatly reducing the occupied space after the multi-tab structure of the final welding area 202 is welded and bent with the switching tab 3 on the premise of not weakening the current carrying capacity of the tab, solving the problem that the bending structure of the multi-tab occupies too much space in the existing multi-tab battery core, providing more space for the active area of the battery core and improving the energy density of the battery.

The above is merely an embodiment of the present utility model, and is not intended to limit the present utility model. Various modifications and variations of the present utility model will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, or the like, which is within the spirit and principles of the present utility model, should be included in the scope of the claims of the present utility model.

Claims (10)

1. The tab folding structure of the multi-tab battery cell is characterized by comprising a battery cell body (1), foil tabs (2) connected to the battery cell body (1), and switching tabs (3);

the foil tab (2) comprises an anode foil tab (2) and a cathode foil tab (2), wherein a plurality of foil tabs (2) with the same polarity are arranged and mutually overlapped to form a multilayer structure, and the multilayer structure comprises an odd layer and an even layer;

the foil tab (2) is of a long sheet structure, the lengths of the foil tabs (2) of odd layers are sequentially increased along the thickness direction of the multilayer structure, and the lengths of the foil tabs (2) of even layers are sequentially increased along the thickness direction of the multilayer structure;

a plurality of foil tabs (2) which are arranged in an overlapping manner and have the same polarity are welded with each other to form a pre-welding area (201) and a final welding area (202), wherein all the foil tabs (2) of an odd layer and an even layer are contacted with each other in the pre-welding area (201), and only the foil tabs (2) of the odd layer or the even layer are contacted with each other in the final welding area (202);

the transfer tab (3) is connected with the foil tab (2) of the final welding area (202).

2. The folded tab structure of a multipolar tab cell according to claim 1, characterized in that the length of the foil tab (2) at an even layer is smaller than the length of the foil tab (2) at the previous odd layer adjacent thereto, and the length of the foil tab (2) at the first even layer is the smallest; in the final welding area (202), only the foil lugs (2) of odd layers are contacted with each other.

3. The folded tab structure of a multipolar tab cell according to claim 1, characterized in that the length of the foil tab (2) at an odd layer is smaller than the length of the foil tab (2) at the previous even layer adjacent thereto, and the length of the foil tab (2) at the first odd layer is the smallest; in the final welding area (202), only even layers of the foil lugs (2) are contacted with each other.

4. A folded tab structure of a multipolar tab cell according to any of claims 1-3, characterized in that the lengths of the plurality of foil tabs (2) of the odd layers are in an arithmetic progression and the lengths of the plurality of foil tabs (2) of the even layers are in an arithmetic progression.

5. The folded tab structure of a multipole tab cell according to claim 4, wherein the tolerance of the length of the foil tab (2) of the odd layers is the same as the tolerance of the length of the foil tab (2) of the even layers.

6. A folded tab structure of a multipolar tab cell according to any of claims 1-3, characterized in that the cell body (1) has a connection end face (102), the foil tabs (2) of the same polarity being arranged on the same connection end face (102) of the cell body (1).

7. The folded tab structure of a multi-tab cell according to claim 6, wherein the foil tab (2) of the final land (202) forms a folded structure with respect to the foil tab (2) of the pre-land (201), the folded direction of the final land (202) being towards the connection end face (102).

8. The tab-folded structure of the multi-tab cell according to claim 7, wherein the switching tab (3) is connected to a surface of the terminal land (202) facing the connection end face (102).

9. The tab-folded structure of the multi-tab cell according to claim 7, wherein the switching tab (3) is connected to a surface of the terminal bonding area (202) facing away from the connection end face (102).

10. A lithium battery comprising a folded tab structure of the multi-tab cell of any one of claims 1-9.