CN115832632A - Pole piece, electric core, battery and electric equipment - Google Patents

Abstract

The invention discloses a pole piece, a battery cell, a battery and an electrical device. The pole piece comprises: a pole piece body, a plurality of die-cut tabs are formed on the pole piece body, and the plurality of die-cut tabs are spaced along a first direction set, and a plurality of die-cut tabs can be stacked; guide tabs, guide tabs include a first body and a second body, the first body is set on the pole piece body, and the pole piece is formed on the first body The first welding area of the main body is welded, the second body protrudes from the pole piece body, and the second welding area is formed on the second body to be welded with the die-cut lug. The pole piece of the present invention can reduce the size and space ratio of the die-cut tab, increase the energy density, and improve the overall welding strength of the diversion tab and the die-cut tab.

Description

Electrode, cell, battery and electrical equipment

technical field

The invention relates to the technical field of batteries, in particular to a pole piece, a battery cell, a battery and electrical equipment.

Background technique

In the related technology, multiple tabs are introduced into the existing structure for increasing the cell magnification, and the multiple tabs are folded and welded into a piece. In order to ensure the welding strength of the tabs and the current carrying capacity of the welding position, the poles The height of the solder print on the lug is large, resulting in a large die-cut area of the lug and low energy density.

Contents of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, an object of the present invention is to provide a pole piece, which can not only improve the welding strength of the tab, but also reduce the size of the die-cut tab and increase the energy density.

The present invention also aims to provide a battery cell for applying the above-mentioned pole pieces.

The present invention also aims to provide a battery for applying the above-mentioned battery cell.

The present invention also aims to provide an electrical device using the above-mentioned battery.

The pole piece according to the embodiment of the present invention includes: a pole piece body, a plurality of die-cut tabs are formed on the pole piece body, the plurality of die-cut tabs are arranged at intervals along the first direction, and the plurality of die-cut tabs are arranged at intervals along the first direction, The die-cut tabs can be stacked; the guide tab includes a first body and a second body, the first body is arranged on the pole piece body, and the first body is formed with The first welding area welded with the pole piece body, the second body protrudes from the pole piece body, and the second body is formed with a second welding area welded with the die-cut tab.

According to the pole piece of the embodiment of the present invention, the first body is arranged on the pole piece body by setting the diversion lug including the first body and the second body, and the first welding with the pole piece body is formed on the first body area, the second body protrudes from the pole piece body, and the second body is formed with a second welding area welded with the die-cut tab, which can reduce the size and space ratio of the die-cut tab, increase the energy density, and improve the flow guide The overall welding strength of lugs and die-cut tabs.

In some embodiments, the current guiding tab extends along a second direction, the second direction is perpendicular to the first direction, and in the second direction, the length of the first welding region is greater than that of the first welding region. 2. The length of the welding area. Under the premise of ensuring the same current-carrying capacity, the width of the weld seam is basically fixed during welding, and the length of the first welding zone is relatively large, so the area of the first welding zone is also relatively large, and the welding strength of the diversion tab is also relatively large. The higher, the higher the security.

In some embodiments, the length of the second welding area in the second direction is 0.5-10 mm.

In some embodiments, the length of the second welding area in the second direction is 1-3 mm.

In some embodiments, the length of the first welding area in the second direction is 4-6 mm.

In some embodiments, the current guiding tab extends along a second direction, the second direction is perpendicular to the first direction, and in the second direction, the plurality of die-cut tabs have the same length, The length of the second body is greater than the length of the die-cut tab. The equal lengths of the plurality of die-cut tabs in the second direction can ensure that the tops of the plurality of die-cut tabs are stacked to be even and orderly, which is convenient for assembly. The length of the second body is greater than the length of the die-cut tab, so that there is sufficient margin for the leaking part of the diversion tab, and other electrical connection components can be connected externally.

In some embodiments, the current guiding tab extends along a second direction, the second direction is perpendicular to the first direction, and in the second direction, the length of the second body is greater than that of the first The length of the body. In this way, it can be ensured that the length of the first body will not be too large, which is beneficial to reducing the overall length of the diversion tab.

In some embodiments, the pole piece body has a first end, a middle portion and a second end arranged along the first direction, and the first body is arranged at the first end, the middle and the second end. at least one of the second ends.

In some embodiments, when the first body is arranged in the middle, a plurality of the die-cut tabs are arranged on both sides of the second body, and are arranged symmetrically with respect to the second body. In this way, the number of die-cut tabs folded in half at one time can be reduced, and the processing difficulty of die-cut tabs can be reduced.

In some embodiments, the thicknesses of the first body and the second body are both 0.05-0.1 mm.

The battery cell according to the embodiment of the present invention includes the aforementioned pole piece.

According to the battery cell of the embodiment of the present invention, the size and space ratio of the die-cut tab can be reduced by the pole piece, the energy density can be increased, and the welding strength of the whole composed of the diversion tab and the die-cut tab can be improved, which is beneficial to Improve the quality of batteries.

A battery according to an embodiment of the present invention includes a plurality of battery cells described above.

An electric device according to an embodiment of the present invention includes the aforementioned battery.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and comprehensible from the description of the embodiments in conjunction with the following drawings, wherein:

Fig. 1 is a schematic structural view of a pole piece according to Embodiment 1 of the present invention;

Fig. 2 is a structural schematic diagram of a diversion tab according to an embodiment of the present invention;

Fig. 3 is a structural schematic diagram of stacked die-cut tabs in the pole piece according to Embodiment 1 of the present invention;

Fig. 4 is a schematic structural view of a pole piece according to Embodiment 2 of the present invention;

Fig. 5 is a schematic structural view of stacked die-cut tabs in the pole piece according to the second embodiment of the present invention;

Fig. 6 is a schematic structural view of the battery cell in the embodiment of the present invention.

Reference signs:

100, pole piece;

10. Pole piece body; 101. Die-cut tabs; 101a, top edge;

20, diversion tab; 210, first body; 210a, first welding area; 220, second body; 220a, second welding area;

1000, battery core; c, center line; 2, negative plate; 3, diaphragm.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

In describing the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " The orientation or positional relationship indicated by "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation shown in the drawings Or positional relationship is only for the convenience of describing the present invention and simplifying the description, but does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of these features, which are used to describe the features differently, without order or importance.

In the description of the present invention, unless otherwise specified, "plurality" means two or more.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

A battery cell refers to a single electrochemical cell with positive and negative electrodes. The difference between a battery cell and a battery cell is that the battery cell contains a protective circuit and a casing, and the battery cell can be used directly, while the battery cell generally cannot be used directly. The battery cell generally includes a positive electrode sheet, a diaphragm, and a negative electrode sheet, and the positive electrode sheet, the diaphragm, the negative electrode sheet, and the diaphragm are stacked together in order to form a battery cell. In order to increase the cell magnification, multiple tabs will be introduced on the pole piece, and the tabs will be folded and welded together. In order to ensure the welding strength and the current carrying capacity of the welding position, the size of the welding area on the tab is generally relatively large, and the energy density is relatively low. , and at the same time, in order to ensure a large welding area on the tab, the size of the tab is also relatively large, and the space ratio is relatively high.

The applicant found that by adding external tabs to the pole piece, the external tabs are welded to the pole piece and the tab separately, which can not only ensure the welding strength, but also reduce the size of the welding area of the tab and increase the energy density. , and helps to reduce the size of the tab on the pole piece.

The pole piece 100 according to the embodiment of the present invention will be described below with reference to FIGS. 1-5 .

As shown in FIGS. 1 to 3 , a pole piece 100 according to an embodiment of the present invention includes a pole piece body 10 and a current guiding tab 20 .

A plurality of die-cut tabs 101 are formed on the pole piece body 10 , the plurality of die-cut tabs 101 are arranged at intervals along the first direction, and the plurality of die-cut tabs 101 can be stacked. The diversion lug 20 includes a first body 210 and a second body 220, the first body 210 is arranged on the pole piece body 10, a first welding area 210a welded with the pole piece body 10 is formed on the first body 210, and the second body 210 is formed on the pole piece body 10. The body 220 protrudes from the pole piece body 10 , and the second body 220 is formed with a second welding area 220 a welded with the die-cut tab 101 .

"Pole piece body 10" may refer to a sheet obtained by coating a conductive active material on a substrate, drying in an oven, and cutting. The pole piece 100 can refer to a positive pole piece or a negative pole piece. When the pole piece 100 is a positive pole piece, the base material of the positive pole piece can be aluminum foil; when the pole piece 100 is a negative pole piece, the base material of the negative pole piece can be copper foil.

“Die-cut tab 101 ” may refer to a tab obtained by die-cutting the pole piece body 10 .

"First direction" can refer to the long-side direction or the short-side direction of the pole piece body 10, and the "first direction" can be specifically set as required. For example, the first direction can be the left-right direction in FIG. 1, that is, the pole piece body 10 in the direction of the long side.

The "current guiding tab 20" may refer to a strip-shaped sheet, and the current guiding tab 20 is made of a conductive metal material for drawing out current. "First body 210" and "second body 220" may refer to dividing the sheet into two parts, the first body 210 is attached to the pole piece body 10, the second body 220 is located outside the pole piece body 10, and stacked The die-cut tabs 101 are attached together. It should be noted that, in FIG. 3 , the guide tab 20 and the die-cut tab 101 are only for illustration, and for the convenience of understanding, they are illustrated as bars instead of lines.

The "first welding area 210a" may refer to the area where the first body 210 and the pole piece body 10 are connected by welding, that is, the part where the first body 210 and the pole piece body 10 are connected after melting. The shape of the first welding area 210a may be a rectangle, a circle, a square, or other shapes, which are not specifically limited here.

The "second welding area 220a" may refer to the area where the second body 220 and the die-cut tab 101 are welded and connected, that is, the part where the second body 220 and the die-cut tab 101 are connected after melting. The shape of the second welding area 220a may be a rectangle, a circle, a square, or other shapes, which are not specifically limited here.

The first welding area 210a and the second welding area 220a make the diversion tab 20 have two welding point positions, which can improve the welding strength of the tab, and the diversion tab 20 is used as a component for drawing current, which is connected to the pole piece body 10 There are many contact surfaces with the die-cut tab 101, which can increase the current-carrying area. Secondly, due to the addition of the flow guide tab 20, the thickness of the tab group formed by the flow guide tab 20 and the die-cut tab 101 is increased, which can ensure the safety of welding. Under the premise of ensuring the same current carrying capacity, the second welding area 220a between the second body 220 and the die-cut tab 101 can be designed to be relatively small, which can reduce the size of the die-cut tab 101 and increase the energy density.

According to the pole piece 100 of the embodiment of the present invention, the first body 210 is arranged on the pole piece body 10 by setting the flow guide lug 20 including the first body 210 and the second body 220, and the first body 210 is formed with a The first welding area 210a of the sheet body 10 is welded, the second body 220 protrudes from the pole piece body 10, and the second body 220 is formed with a second welding area 220a welded with the die-cut tab 101, which can reduce the size of the die-cut tab. The size and space ratio of 101 increases the energy density and improves the overall welding strength of the diversion tab 20 and the die-cut tab 101 .

In some embodiments, as shown in FIG. 1 and FIG. 2 , the current guiding tab 20 extends along a second direction, the second direction is perpendicular to the first direction, and in the second direction, the length of the first welding region 210a is greater than that of the second direction. The length of the welding area 220a.

In combination with the foregoing, the "second direction" may refer to the width direction of the pole piece body 10 , that is, the up and down direction of the pole piece body 10 in FIG. 1 . Of course, the second direction can also be other directions, which can be specifically set according to needs, as long as it is perpendicular to the first direction. Under the premise of ensuring the same current-carrying capacity, the width of the weld seam is basically the same during welding, and the length of the first welding region 210a is relatively large, which makes the area of the first welding region 210a relatively large, and the current-guiding tab 20 The welding strength is higher and the safety is higher.

That is to say, by "the length of the first welding region 210a is greater than the length of the second welding region 220a", the welding area of the first welding region 210a can be increased, the welding area of the second welding region 220a can be reduced, and the energy density can be improved.

In some embodiments, the length of the second welding region 220a in the second direction is 0.5-10 mm. That is to say, the length of the second welding area 220a can be any value in 0.5mm, 1mm, 2mm, 2.5mm, 3.5mm, 4mm, 5.25mm, 6mm, 7mm, 8.5mm, 9mm, 10mm, and can be Make a selection. Of course, this is just an example, and the length of the second welding region 220 a in the second direction only needs to be any value within the range of 0.5-10 mm, and details will not be repeated here.

In some embodiments, the length of the second welding area 220 a in the second direction is 1-3 mm. That is to say, the length of the second welding area 220a can be any value among 1 mm, 1.5 mm, 2 mm, 2.5 mm, and 3 mm, which can be selected according to needs. Of course, this is just an example, and the length of the second welding region 220 a in the second direction only needs to be any value within the range of 1-3 mm, and details will not be repeated here.

In some embodiments, the length of the first welding region 210 a in the second direction is 4-6 mm. That is to say, the length of the first welding area 210a can be any value among 4mm, 4.5mm, 5mm, 5.5mm, and 6mm, which can be selected according to needs. Of course, this is just an example, and the length of the first welding region 210 a in the second direction only needs to be any value within the range of 4-6 mm, and details will not be repeated here.

In some embodiments, as shown in FIG. 1 , the current guiding tab 20 extends along a second direction, and the second direction is perpendicular to the first direction. In the second direction, the lengths of the plurality of die-cut tabs 101 are equal, and the second direction The length of the body 220 is greater than the length of the die-cut tab 101 . After stacking a plurality of die-cut tabs 101, the tops can be even and orderly, which is convenient for subsequent assembly operations. The length of the second body 220 is longer than the length of the die-cut tab 101 , so that sufficient margin can be left for the exposed part of the guide tab 20 , which provides convenience for connecting the guide tab 20 to other components.

In some embodiments, the widths of the plurality of die-cut tabs 101 in the first direction are equal, so that the plurality of die-cut tabs 101 can be completely overlapped when stacked, which can not only improve regularity, but also facilitate subsequent assembly operate.

In some embodiments, as shown in FIG. 2 , the guide tab 20 extends along a second direction, the second direction is perpendicular to the first direction, and in the second direction, the length of the second body 220 is greater than the length of the first body 210 . The second body 220 is used to weld the die-cut lug 101 and connect to other external parts. The first body 210 is used to weld the pole piece body 10. The length of the second body 220 is greater than the length of the first body 210, avoiding the first body 210 If the length is too long, it is beneficial to reduce the overall length of the current guiding tab 20, save materials and improve welding efficiency.

In some embodiments, the pole piece body 10 has a first end, a middle part and a second end arranged along the first direction, and the first body 210 is arranged on at least one of the first end, the middle part and the second end . Referring to the foregoing, the first direction may refer to the left-right direction in FIG. 1, the first end may refer to the leftmost end of the pole piece body 10, the second end may refer to the rightmost end of the pole piece body 10, and the first body 210 The position on the pole piece body 10 can include the following situations:

For example, as shown in Figure 1, the first body 210 can be welded on the first end, and the pole piece body 10 is made into a winding core by folding or winding. When the pole piece body 10 is wound from right to left A plurality of die-cut tabs 101 are stacked together and then welded to the second body 220 to improve the processing efficiency of stacked die-cut tabs 101 .

For example, the first body 210 can be welded on the second end. Referring to the above, the pole piece body 10 can be wound from left to right, which can also improve the processing efficiency of the folded die-cut tab 101 .

For example, as shown in FIG. 4, the first body 210 may be welded on the middle portion.

For example, the first body 210 may be welded on the first end and the second end, that is to say, there are two first bodies 210, which are respectively provided on the first end and the second end.

For example, the first body 210 may be welded on the first end and the middle, that is to say, there are two first bodies 210, which are respectively provided on the first end and the middle.

For example, the first body 210 may be welded on the middle part and the second end part, that is to say, there are two first bodies 210, which are respectively arranged on the middle part and the second end part.

For example, the first body 210 can be welded on the first end, the middle and the second end, that is to say, the number of the first body 210 is three, respectively arranged at the first end, the middle and the second end department.

In some embodiments, as shown in FIG. 4 , when the first body 210 is disposed in the middle, a plurality of die-cut tabs 101 are disposed on both sides of the second body 220 , and are arranged symmetrically with respect to the second body 220 .

As shown in Figure 4 and Figure 5, the number of die-cut tabs 101 is four, two are arranged on the left side of the guide tab 20, and the remaining two are arranged on the right side of the guide tab 20, and the pole piece body Fold the two die-cut tabs 101 in half from left to right on the left side of the pole piece body 10, and then fold them to the current flow tab 20, and then fold the two die-cut tabs 101 in half from right to left on the right side of the pole piece body 10 , and then bend the guide tab 20. In this way, it is possible to avoid folding four die-cut tabs 101 at a time, and reduce the processing difficulty of folding die-cut tabs 101 . It should be noted that the guide tab 20 and the die-cut tab 101 in FIG. 5 are only for illustration, and for the convenience of understanding, they are illustrated as bars instead of lines.

It can be understood that by means of "a plurality of die-cut tabs 101 are arranged on both sides of the second body 220 and arranged symmetrically with respect to the second body 220", the number of die-cut tabs 101 folded in half at one time can be reduced, and the number of die-cut tabs 101 can be reduced by more points. Folding and die-cutting the tab 101 in half reduces the difficulty of folding and die-cutting the tab 101 in half.

In some embodiments, the thicknesses of the first body 210 and the second body 220 are both 0.05-0.1 mm. That is to say, the thickness of the first body 210 and the second body 220 are equal, both can be any value in 0.05mm, 0.06mm, 0.07mm, 0.075mm, 0.08mm, 0.09mm, 0.1mm, and according to Need to be able to choose. Of course, this is just an example, and the thicknesses of the first body 210 and the second body 220 only need to be any value within the range of 0.05-0.1 mm, and details will not be repeated here.

In some embodiments, the thicknesses of the first body 210 and the second body 220 are both 0.06-0.08 mm. That is to say, the first body 210 and the second body 220 have the same thickness, and both of them can be any value in 0.06mm, 0.07mm, 0.08mm, and can be selected according to needs. Of course, this is just an example, and the thicknesses of the first body 210 and the second body 220 only need to be any value within the range of 0.06-0.08 mm, and details will not be repeated here.

In some embodiments, as shown in FIG. 2 , the current guiding tab 20 has a centerline c, the centerline c is parallel to the second direction, the first welding region 210a is arranged symmetrically with respect to the centerline c, and the second welding region 220a is arranged symmetrically with respect to the centerline c Symmetrical setting.

Referring to the foregoing, the first direction may refer to the left-right direction, and the second direction may refer to the up-down direction, then the "center line c" may refer to a straight line that equally divides the diversion tab 20 in the left-right direction, and the second welding area 220a is about The central line c is arranged symmetrically, that is, the welding areas on both sides of the central line c are equal in size, and the force on the left and right sides of the diversion tab 20 is uniform, which can ensure the welding reliability and stability of the diversion tab 20 .

In some embodiments, in the first direction, the width of the first welding area 210 a is equal to the width of the first body 210 , and the width of the second welding area 220 a is equal to the width of the second body 220 . In this way, the width of the first welding area 210a and the second welding area 220a can be increased as much as possible, the welding reliability of the first body 210 and the pole piece body 10 can be further improved, and the second body 220 and the die-cut pole can be improved. Soldering reliability of ear 101.

In some embodiments, in the first direction, the width of the second body 220 is equal to the width of the die-cut tab 101, which can ensure a relatively large contact surface between the second body 220 and the die-cut tab 101, thereby increasing The area of the second bonding region 220a is large.

In some embodiments, in the first direction, the width of the second body 220 is smaller than the width of the die-cut tab 101 .

In some embodiments, as shown in FIG. 3 , the die-cut tab 101 has a top edge 101 a away from the pole piece body 10 , and the second welding region 220 a is disposed close to the top edge 101 a. For example, the top edge 101a may refer to the upper edge of the die-cut tab 101 , in this way the welding of the second body 220 and the die-cut tab 101 is facilitated.

In some embodiments, the second welding area 220a is set close to the middle of the die-cut tab 101 . In this way, it can ensure that the second welding area 220a is fully welded to the die-cut tab 101 , which is beneficial to reduce missing welding.

The battery cell 1000 according to the embodiment of the present invention includes the aforementioned pole piece 100 .

As shown in FIG. 6 , it should be noted that the battery cell 1000 also includes a negative electrode sheet 2 and a separator 3 , and the electrode sheet 100 constitutes a positive electrode sheet. "Diaphragm 3" can refer to a layer of membrane material between the positive electrode sheet and the negative electrode sheet 2, which isolates the positive electrode sheet and the negative electrode sheet 2 and prevents the electrons in the battery cell 1000 from freely passing through, so that the ions in the electrolyte are separated between the positive and negative electrodes. Pass freely between poles. Wherein, the battery cell 1000 may be a winding core, or a laminated battery cell. It should be noted that other configurations and operations of the battery cell 1000 are known to those skilled in the art and will not be described in detail here.

According to the battery cell 1000 of the embodiment of the present invention, the size and space ratio of the die-cut tab 101 can be reduced through the pole piece 100, the energy density can be improved, and the overall performance of the guide tab 20 and the die-cut tab 101 can be improved. The welding strength is conducive to improving the quality of the battery cell 1000.

The battery according to the embodiment of the present invention includes the aforementioned battery cell 1000 .

It should be noted that the "battery" mentioned in the present invention may refer to a battery cell or a battery module, wherein a battery module includes a plurality of battery cells. "Battery" may also refer to a battery pack, which includes a plurality of grouped battery packs.

An electric device according to an embodiment of the present invention includes the aforementioned battery.

It should be noted that the electrical equipment can refer to vehicles, new energy vehicles, etc. For example, when the electrical equipment is a vehicle, the battery can supply power for electrical components in the vehicle; when the electrical equipment is a new energy vehicle, the battery can It is a power battery for new energy vehicles, which is used to supply power to the drive motor.

Electrical equipment can also refer to equipment that needs electricity, such as drones and robots. For example, when the electrical equipment is a When the robot is running, the battery powers the electrical components in the robot.

In the description of this specification, descriptions with reference to the terms "some embodiments", "further" or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in the scope of the present invention. In at least one embodiment or example. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the invention is defined by the claims and their equivalents.

Claims (13)

1. A pole piece, comprising:

the pole piece comprises a pole piece body, wherein a plurality of die-cut tabs are formed on the pole piece body, the die-cut tabs are arranged at intervals along a first direction, and the die-cut tabs can be stacked;

the flow guide lug comprises a first body and a second body, the first body is arranged on the pole piece body, a first welding area welded with the pole piece body is formed on the first body, the second body is protruded out of the pole piece body, and a second welding area welded with the die-cutting lug is formed on the second body.

2. The pole piece of claim 1, wherein the flow tabs extend in a second direction, the second direction being perpendicular to the first direction, the first weld area having a length greater than a length of the second weld area in the second direction.

3. The pole piece of claim 2 wherein the length of the second weld area in the second direction is 0.5 to 10mm.

4. The pole piece of claim 2 wherein the length of the second weld area in the second direction is 1 to 3mm.

5. The pole piece of claim 4 wherein the length of the first weld area in the second direction is between 4 and 6mm.

6. The pole piece of claim 1 wherein the flow tab extends in a second direction, the second direction being perpendicular to the first direction, wherein a plurality of the die cut tabs are of equal length in the second direction, and wherein the length of the second body is greater than the length of the die cut tabs.

7. The pole piece of claim 1 wherein the flow guide tab extends in a second direction, the second direction being perpendicular to the first direction, the second body having a length greater than the first body in the second direction.

8. The pole piece of claim 1 wherein the pole piece body has a first end portion, a middle portion and a second end portion disposed along the first direction, the first body being disposed on at least one of the first end portion, the middle portion and the second end portion.

9. The pole piece of claim 8, wherein when the first body is disposed in the middle portion, the plurality of die-cut tabs are disposed on two sides of the second body and symmetrically disposed about the second body.

10. The pole piece of claim 1, wherein the first body and the second body are each 0.05-0.1 mm thick.

11. A battery cell comprising the pole piece of any one of claims 1 to 10.

12. A battery comprising a plurality of cells of claim 11.

13. An electrical device comprising the battery of claim 12.

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