CN216354308U

CN216354308U - Pole piece and battery cell

Info

Publication number: CN216354308U
Application number: CN202122993851.9U
Authority: CN
Inventors: 彭宁
Original assignee: Zhuhai Cosmx Battery Co Ltd
Current assignee: Zhuhai Cosmx Battery Co Ltd
Priority date: 2021-11-30
Filing date: 2021-11-30
Publication date: 2022-04-19
Anticipated expiration: 2031-11-30

Abstract

The utility model provides a pole piece and a battery cell, and relates to the technical field of lithium batteries. The pole piece comprises a current collector and a pole lug; the current collector comprises an insulating layer, and a first metal layer and a second metal layer which respectively cover two opposite surfaces of the insulating layer; the current collector comprises a first area and a second area, the second area is turned over to form a turning part, and the surface of the turning part covered with the first metal layer is opposite to the surface of the first area covered with the first metal layer; the surface of the folded part covered with the second metal layer faces to the same side as the surface of the first area covered with the first metal layer; the first end of the tab is simultaneously attached to the surface of the second metal layer covered by the turnover part and the surface of the first metal layer covered by the first area. Therefore, micro short circuit of the lithium ion battery in the nail penetration test can be reduced, so that the lithium ion battery is prevented from being ignited and exploded, and the safety performance of the lithium ion battery is improved.

Description

Pole piece and battery cell

Technical Field

The utility model relates to the technical field of lithium batteries, in particular to a pole piece and a battery cell.

Background

With the development of science and technology, the technology of lithium ion batteries is rapidly developed. Meanwhile, the lithium ion battery is widely applied to the fields of consumer electronics products, new energy vehicles, energy storage and the like due to the advantages of high energy density, good cycle performance, small environmental pollution and the like.

With the wide application of lithium ion batteries in various fields, people pay more and more attention to the safety performance of the lithium ion batteries. Among the correlation technique, lithium ion battery is when carrying out the drift bolt test, and a large amount of little short circuits can appear in the inside lithium ion battery to lead to a large amount of heats of accumulating in the inside short time of lithium ion battery, and then lead to lithium ion battery to catch fire, explode, seriously threaten user's life and property safety.

Therefore, how to improve the safety performance of the lithium ion battery becomes the focus of current research.

SUMMERY OF THE UTILITY MODEL

The utility model provides a pole piece and a battery cell, which can reduce micro short circuit in a lithium ion battery during a nail penetration test so as to reduce heat accumulated in the lithium ion battery, thereby avoiding the ignition and explosion of the lithium ion battery and further being beneficial to improving the safety performance of the lithium ion battery.

In a first aspect, the present invention provides a pole piece, including a current collector and a tab; the current collector comprises an insulating layer, and a first metal layer and a second metal layer which respectively cover two opposite surfaces of the insulating layer; the current collector comprises a first area and a second area, the second area is turned over to form a turning part, and the surface of the turning part covered with the first metal layer is opposite to the surface of the first area covered with the first metal layer; the surface of the folded part covered with the second metal layer faces to the same side as the surface of the first area covered with the first metal layer; the first end of utmost point ear simultaneously with the cover of turning over the book portion has the surface of second metal level, and, the cover of first region has the surface laminating of first metal level.

The pole piece provided by the utility model comprises a current collector and a pole lug. The current collector comprises an insulating layer, a first metal layer and a second metal layer, and the first metal layer and the second metal layer are respectively covered on two opposite surfaces of the insulating layer so as to realize the current collecting effect of the current collector; the insulating layer can reduce the little short circuit that appears inside the lithium ion battery in the drift bolt is experimental to reduce the inside accumulated heat of lithium ion battery, thereby can avoid lithium ion battery to catch fire, explode, and then be favorable to improving lithium ion battery's security performance.

Meanwhile, the current collector comprises a first area and a second area, the second area is turned over to form a turning part, and the surface of the turning part covered with the first metal layer is opposite to the surface of the first area covered with the first metal layer; the surface of the folded part covered with the second metal layer faces to the same side as the surface of the first area covered with the first metal layer; the first end of utmost point ear covers the surface that has the second metal level with the folding portion simultaneously to, the surface laminating that first regional cover has the first metal level, thereby make the relative both sides of mass flow body all be connected and switch on with utmost point ear, and then can reduce the internal resistance behind the pole piece formation electricity core.

As for the pole piece, optionally, the surface of the folded portion covered with the second metal layer is flush with at least part of the surface of the current collector covered with the first metal layer.

As for the pole piece, optionally, the second end of the tab extends out of the first edge of the current collector, and the extending direction of the folded portion after being folded is from the first end of the tab to the second end of the tab.

In the pole piece as described above, optionally, a gap is formed between one side edge of the folded portion close to the second end of the tab and the first edge of the current collector; the first end of utmost point ear with the folding portion, and, the mass flow body be located the folding portion with the partial laminating between the first edge is connected.

As for the pole piece, optionally, the pole piece further includes an active layer, the active layer is coated on the surface of the current collector, and the active layer avoids a pole lug groove on the surface of one side of the current collector; the first ends of the turnover part and the pole lugs are located in the pole lug grooves.

As for the pole piece, optionally, in a direction perpendicular to the first end of the tab pointing to the second end of the tab, the folded portion is located in the middle of the tab slot, and the tab is located in the middle of the tab slot.

In the pole piece, optionally, the ratio of the width of the folded part to the width of the tab ranges from 0.5 to 1.5.

The pole piece as described above, optionally, the width of the pole lug groove ranges from 2mm to 30 mm.

The pole piece as described above, optionally, the length of the pole lug groove ranges from 2mm to 40 mm.

In the pole piece as described above, optionally, the sum of the thickness of the folded part and the thickness of the tab does not exceed the thickness of the active layer.

In the pole piece, optionally, the tab slot is located in a range from one third to two thirds of the length of the pole piece in a direction perpendicular to a direction in which the first end of the tab points to the second end of the tab.

In a second aspect, the utility model provides a battery cell comprising a separator and a pole piece as described in any of the above, the separator and the pole piece being arranged in a stack to form a laminated battery cell, or the separator and the pole piece being arranged in a wound configuration to form a wound battery cell.

The battery cell provided by the utility model comprises the diaphragm and the pole piece, wherein the diaphragm and the pole piece can be arranged in a stacking mode to form a laminated battery cell, or the diaphragm and the pole piece can be arranged in a winding mode to form a winding battery cell.

The pole piece comprises a current collector and a pole lug. The current collector comprises an insulating layer, a first metal layer and a second metal layer, and the first metal layer and the second metal layer are respectively covered on two opposite surfaces of the insulating layer so as to realize the current collecting effect of the current collector; the insulating layer can reduce the little short circuit that appears inside the lithium ion battery in the drift bolt is experimental to reduce the inside accumulated heat of lithium ion battery, thereby can avoid lithium ion battery to catch fire, explode, and then be favorable to improving lithium ion battery's security performance.

In addition to the technical problems solved by the embodiments of the present disclosure, the technical features constituting the technical solutions, and the advantages brought by the technical features of the technical solutions, other technical problems that can be solved by the pole piece and the battery cell provided by the embodiments of the present disclosure, other technical features included in the technical solutions, and advantages brought by the technical features will be further described in detail in the detailed description.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic cross-sectional view of a current collector provided in an embodiment of the present invention;

FIG. 2 is a schematic top view of a pole piece according to an embodiment of the present invention;

fig. 3 is a schematic cross-sectional view of a pole piece according to an embodiment of the utility model.

Description of reference numerals:

100-pole piece;

110-a current collector; 111-a first metal layer; 112-a second metal layer; 113-an insulating layer; 114-a fold over; 115-folding holes; 116-polar ear canal; 117 — a first edge;

120-pole ear; 121-tab glue;

130-active layer.

Detailed Description

In the related art, the battery cell mainly includes a negative electrode plate, a positive electrode plate, a diaphragm, a negative electrode tab and a positive electrode tab, the negative electrode tab is welded to the negative electrode plate, the positive electrode tab is welded to the positive electrode plate, and the negative electrode plate, the positive electrode plate and the insulating diaphragm are stacked in a preset order or wound to form the battery cell. The current collector of the positive plate is usually an aluminum foil, and the current collector of the negative plate is usually a copper foil. When the lithium ion battery carries out the drift bolt test, aluminium foil and copper foil can lead to lithium ion battery inside to take place a large amount of little short circuits to lead to a large amount of heats of lithium ion battery inside short time internal accumulation, and then lead to lithium ion battery to catch fire, explode, seriously threaten user's life and property safety.

In order to solve the technical problem, the utility model provides a pole piece and a battery cell, wherein the pole piece comprises a current collector and a tab. The current collector comprises an insulating layer, a first metal layer and a second metal layer, and the first metal layer and the second metal layer are respectively covered on two opposite surfaces of the insulating layer so as to realize the current collecting effect of the current collector; the insulating layer can reduce the little short circuit that appears inside the lithium ion battery in the drift bolt is experimental to reduce the inside accumulated heat of lithium ion battery, thereby can avoid lithium ion battery to catch fire, explode, and then be favorable to improving lithium ion battery's security performance.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

Fig. 1 is a schematic cross-sectional view of a current collector provided in an embodiment of the present invention; FIG. 2 is a schematic top view of a pole piece according to an embodiment of the present invention; fig. 3 is a schematic cross-sectional view of a pole piece according to an embodiment of the utility model.

Referring to fig. 1 to 3, the present embodiment provides a pole piece 100 including a current collector 110 and a tab 120. The current collector 110 includes an insulating layer 113, a first metal layer 111, and a second metal layer 112, and the first metal layer 111 and the second metal layer 112 respectively cover opposite sides of the insulating layer 113.

Illustratively, the pole piece 100 may be a positive pole piece, and the insulating layer of the positive pole piece may be polyethylene terephthalate (PET), non-woven fabric, or other insulating material meeting the requirements of the present embodiment. The first metal layer and the second metal layer of the positive plate can be aluminum film layers, and the aluminum film layers can cover the surface of the insulating layer of the positive plate in a film coating mode and the like.

The electrode sheet 100 may be a negative electrode sheet, and the insulating layer of the negative electrode sheet may be polyethylene terephthalate (PET), non-woven fabric, or other insulating material meeting the requirements of the present embodiment. The first metal layer and the second metal layer of the negative plate can be copper film layers, and the copper film layers can cover the surface of the insulating layer of the negative plate in a coating mode and the like.

Optionally, the thickness of the insulating layer 113 ranges from 1 μm to 20 μm. Illustratively, the thickness of the insulating layer 113 may be set to 1 μm, 3 μm, 5 μm, 7 μm, 10 μm, 13 μm, 15 μm, 17 μm or 20 μm according to actual needs, so that not only the insulating layer 113 may be prevented from being too thick, which may result in a large occupied space inside the battery; and the insulating layer 113 can be prevented from being too thin, and the improvement on the nail penetration performance and the safety performance of the battery is not significant enough.

Optionally, the thickness ranges of the first metal layer 111 and the second metal layer 112 are both 0.1 μm to 5 μm. For example, the thickness of the first metal layer 111 or the second metal layer 112 may be set to 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 4 μm, or 5 μm according to actual needs, so as to avoid not only that the first metal layer 111 or the second metal layer 112 is too thin and affects the conduction and current collection effects of the current collector 110, but also that the first metal layer 111 or the second metal layer 112 is too thick and occupies a relatively large space inside the battery.

Referring to fig. 2 and 3, the current collector 110 includes a first region and a second region, the second region is folded to form a folded portion 114, and a surface of the folded portion 114 covered with the first metal layer 111 is opposite to a surface of the first region covered with the first metal layer 111. The surface of the folded portion 114 covered with the second metal layer 112 faces the same side as the surface of the first region covered with the first metal layer 111. The first end of the tab 120 is simultaneously attached to the surface of the folded portion 114 covered with the second metal layer 112 and the surface of the first region covered with the first metal layer 111.

The second end of the tab 120 may extend beyond the first edge 117 of the current collector 110 to form two poles of the cell, thereby facilitating electrical connection of the cell to an external device or circuit. As shown in fig. 2, the first edge 117 of the current collector 110 is a side edge of the current collector 110 between the first and second ends of the tab 120. Alternatively, the first edge 117 of the current collector 110 may be perpendicular to the direction in which the first end of the tab 120 is directed toward the second end.

Alternatively, the flap 114 may be rectangular, circular, or any other shape. One or more folded parts 114 may be provided according to actual needs, and one tab 120 may be correspondingly connected to one folded part 114, or one tab 120 may be correspondingly connected to a plurality of folded parts 114. The number, size, arrangement and the like of the folded portions 114 may be set by referring to the number and size of the tabs 120 and the area of the tabs 120 connected to the current collector 110, and the like, which is not described in detail herein.

Taking the folded part 114 as an example of a rectangle, during actual processing, three sides of the rectangle can be cut out from the second area of the current collector 110 by laser cutting or die cutting, and the part of the current collector 110 located in the rectangular area is folded by 180 degrees along one uncut side of the rectangle toward the side of the first area of the current collector 110 covered with the first metal layer 111, so as to form the folded part 114. After the part of the current collector in the rectangular area is folded, the rectangular area is formed into the folding hole 115.

At this time, the surface of the folded portion 114 covered with the first metal layer 111 is attached to the surface of the first region covered with the first metal layer 111, so as to save space. The surface of the folded portion 114 covered with the second metal layer 112 faces the same side as the surface of the first area covered with the first metal layer 111, so that when the tab 120 is attached to the surface of the current collector 110 covered with the first metal layer 111, the tab can be attached to the surface of the folded portion 114 covered with the second metal layer 112 at the same time, and the surface of the first area covered with the first metal layer 111 is attached to be connected, thereby realizing the double-sided conduction of the current collector 110, and reducing the internal resistance of the battery cell made of the electrode plate 100 of the present embodiment.

Optionally, the tab 120 may be rectangular and long, or may be provided with other shapes according to actual needs. One or more tabs 120 may be arranged on the pole piece 100 according to actual needs, and for example, one tab may be arranged on a pole piece of the laminated battery cell; one or more tabs can be arranged on the pole piece of the winding type battery cell, and when one tab is arranged on the pole piece of the winding type battery cell, the tab can be arranged at the head end of the pole piece in the winding direction or the middle part of the pole piece in the winding direction. The tab 120 may be made of aluminum, copper, nickel, or the like.

Illustratively, the rectangular strip-shaped tab 120 may have a length range of 5mm to 100mm, a width range of 1mm to 20mm, and a thickness range of 0.01mm to 1mm, and the tab 120 may have a uniform thickness, or may be formed by combining different thicknesses and different materials. The first end of the rectangular strip-shaped tab can be simultaneously attached to the surface of the current collector 110 covered with the first metal layer 111, and the surface of the folded part 114 covered with the second metal layer 112, so that the first metal layer 111 and the second metal layer 112 on the two opposite sides of the current collector 110 are both communicated with the tab 120, the current collection effect of the current collector 110 is better realized, and the internal resistance in the current collection process is reduced. The second end of the rectangular strip-shaped tab extends out of the first edge 117 of the current collector 110, so that two electrodes of the battery cell are formed in the following process and are conducted with an external device or an external circuit. The second end of the rectangular strip-shaped tab may be provided with tab glue 121 covering opposite sides of the tab 120, so as to ensure the sealing property of the extended position of the tab 120 when the battery cell is packaged.

Optionally, the tab 120 may be attached to the current collector 110 by riveting, ultrasonic welding, laser welding, resistance welding, or conductive adhesive.

Referring to fig. 3, optionally, the surface of the folded portion 114 covered with the second metal layer 112 is flush with at least a portion of the surface of the first region covered with the first metal layer 111. For example, the surface of the folded portion 114 covered with the second metal layer 112 may be flush with the surface of the portion of the first region between the folded portion 114 and the first edge 117 of the current collector 110 covered with the first metal layer 111. Alternatively, the surface of the folded part 114 covered with the second metal layer 112 may be flush with the surface of the portion of the current collector 110 around the folded part 114 covered with the first metal layer 111.

During the concrete implementation, the first end laminating of utmost point ear 120 is on the parallel and level surface of turning over folding portion 114 and mass flow body 110 to can guarantee utmost point ear 120 simultaneously with turn over folding portion 114 cover have the surface of second metal layer 112, and, the surface that covers that has first metal layer 111 of first region closely laminates, and then not only be favorable to guaranteeing the reliability that utmost point ear 120 connects, be favorable to guaranteeing the first metal layer 111 and the second metal layer 112 of mass flow body 110 all with the reliability that utmost point ear 120 switched on moreover, in order to guarantee the reliability that mass flow body 110 two-sided switched on.

With continued reference to fig. 3, in a possible implementation, the folded direction of the folded part 114 may be directed from the first end of the tab 120 to the second end of the tab 120, that is, the folded part 114 may be located between the folded hole 115 and the first edge 117 of the current collector 110, it is understood that the folded part 114 includes a folded region and a flat region connected to the folded region, and the folded direction of the folded part 114 refers to a direction of an end of the flat region far from the folded region. In another possible implementation, the direction of extension of the folded part 114 may also be directed from the second end of the tab 120 to the first end of the tab 120, i.e., the folded hole 115 may be located between the folded part 114 and the first edge 117 of the current collector 110. In other possible implementation manners, the extending direction of the folded part 114 may also be perpendicular to the direction in which the first end of the tab 120 points to the second end of the tab, or an included angle may also be formed between the extending direction of the folded part 114 and the direction in which the first end of the tab 120 points to the second end of the tab, and the included angle may be an acute angle or an obtuse angle.

With continued reference to fig. 3, for example, a side edge of the folded portion 114 close to the second end of the tab 120 is spaced from the first edge 117 of the current collector 110; the first end of the tab 120 is in snug connection with the folded portion 114 and the portion of the current collector 110 between the folded portion 114 and the first edge 117 of the current collector 110. Alternatively, the first end of the tab 120 may be in fit connection with the folded portion 114, and a partial region of the current collector 110 located at the folded portion 114 and far away from the first edge 117 of the current collector 110. Alternatively, the first end of the tab 120 may be attached to the folded portion 114 and other areas of the current collector 110 according to actual needs.

Referring to fig. 2 and 3, the pole piece 100 further includes an active layer 130, and the active layer 130 is coated on the surface of the current collector 110, and it can be understood that the active layer 130 can be coated on one side or both sides of the current collector 110, or a partial area of one side of the current collector 110, or partial areas of both sides of the current collector, according to the manufacturing requirements of the pole piece.

The active layer 130 is set aside from the tab slot 116 on the surface of one side of the current collector 110, the folded part 114 and the first end of the tab 120 are both located in the tab slot 116, at this time, the current collector 110 is kept in an exposed state in the tab slot 116, so that the folded part 114 is arranged on the current collector 110 in the tab slot 116; the first end of the tab 120 is received in the tab slot 116, and the first end of the tab 120 covers at least a portion of the folded portion 114 and a portion of the current collector 110 outside the folded portion 114. The first end of the tab 120 is received in the tab slot 116, which is beneficial to keeping the surface of the pole piece 100 flat. After the tab 120 is connected with the current collector 110 and the folded part 114 in the tab slot 116, the entire tab slot 116 may be covered with an insulating glue layer, so as to not only facilitate avoiding lithium precipitation on the surface of the tab 120, but also facilitate ensuring the insulating property of the tab slot 116.

In specific implementation, the active layer 130 is coated on the current collector 110, and then the active layer 130 on the surface of the current collector 110 is removed by laser cleaning, foaming, mechanical processing, or the like, so as to obtain the tab slot 116. Alternatively, the thickness of the active layer 130 may range from 10 μm to 200 μm, and for example, the thickness of the active layer 130 may be set to 10 μm, 50 μm, 100 μm, 150 μm or 200 μm according to actual needs.

Referring to fig. 2, alternatively, the folded portion 114 is located in the middle of the tab slot 116, and the tab 120 is located in the middle of the tab slot 116, in a direction perpendicular to a direction in which the first end of the tab 120 points to the second end of the tab 120, so that a sufficient attachment area between the tab 120 and the folded portion 114 can be ensured, thereby improving the reliability of the attachment connection between the tab 120 and the folded portion 114. It is understood that the direction perpendicular to the first end of the tab 120 toward the second end of the tab 120 is a direction parallel to the plane of the tab in fig. 2.

Optionally, the ratio of the width of the folded part 114 to the width of the tab 120 is in the range of 0.5 to 1.5, and it is understood that the width of the folded part 114 is the extension of the folded part 114 in the direction perpendicular to the direction in which the first end of the tab 120 points to the second end of the tab 120, and the width of the tab 120 is the extension of the tab 120 in the direction perpendicular to the direction in which the first end of the tab 120 points to the second end of the tab 120. For example, the ratio of the width of the folded part 114 to the width of the tab 120 may be set to 0.5, 0.7, 0.9, 1.0, 1.3, 1.5, etc. according to actual needs.

Alternatively, the width of the tab slot 116 ranges from 2mm to 30mm, and it is understood that the width of the tab slot 116 is an extension of the tab slot 116 in a direction perpendicular to a direction in which the first end of the tab 120 is directed toward the second end of the tab 120. Illustratively, the width of the tab slot 116 may be set to 2mm, 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, etc. according to actual needs.

Alternatively, the length of the tab slot 116 ranges from 2mm to 40mm, and it is understood that the length of the tab slot 116 is an extension of the tab slot 116 in a direction in which the first end of the tab 120 is directed toward the second end of the tab 120. Illustratively, the length of the lug groove 116 can be set to 2mm, 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, etc. according to actual needs.

Optionally, the depth of the tab slot 116 is 0.01mm to 1 mm. Illustratively, the depth of the lug groove 116 may be set to 0.01mm, 0.05mm, 0.1mm, 0.3mm, 0.5mm, 0.7mm, 1mm, etc., according to actual needs.

It will be appreciated that the size of the folded over portion 114 is less than or equal to the size of the tab slot 116 in a direction perpendicular to the direction in which the first end of the tab 120 points toward the second end of the tab 120. The size of the folded-over portion 114 is smaller than the size of the tab slot 116 in a direction in which the first end of the tab 120 is directed toward the second end of the tab 120.

Optionally, the sum of the thickness of the folded part 114 and the thickness of the tab 120 does not exceed the thickness of the active layer 130, so as to be beneficial to ensuring the consistency of the overall thickness of the cell.

Optionally, the tab slot 116 is located in a range of one third to two thirds of the total length of the pole piece 100 in a direction perpendicular to the direction in which the first end of the tab 120 points toward the second end of the tab 120. That is, the tab slot 116 is provided in the middle region of the pole piece 100 in a direction perpendicular to the direction in which the first end of the tab 120 is directed toward the second end of the tab 120. Illustratively, the tab slot 116 may be located one-third, one-half, or two-thirds, etc. of the total length of the pole piece 100 in a direction perpendicular to the first end of the tab 120 pointing toward the second end of the tab 120.

In summary, the pole piece 100 provided in this embodiment includes a current collector 110 and a tab 120. The current collector 110 comprises an insulating layer 113, a first metal layer 111 and a second metal layer 112, and the first metal layer 111 and the second metal layer 112 respectively cover two opposite sides of the insulating layer 113, so that the current collecting effect of the current collector 110 is realized; the insulating layer 113 can reduce the micro short circuit inside the lithium ion battery in the nail penetration test to reduce the heat accumulated inside the lithium ion battery, so that the ignition and explosion of the lithium ion battery can be avoided, and the safety performance of the lithium ion battery can be improved.

Meanwhile, by arranging the current collector 110 to include a first area and a second area, the second area is turned over to form a turned portion 114, and the surface of the turned portion 114 covered with the first metal layer 111 is opposite to the surface of the first area covered with the first metal layer 111; the surface of the folded part 114 covered with the second metal layer 112 faces the same side as the surface of the first area covered with the first metal layer 111; the first end of the tab 120 is attached to the surface of the folded portion 114 covered with the second metal layer 112, and the surface of the first region covered with the first metal layer 111, so that the two opposite surfaces of the current collector 110 are connected and conducted with the tab 120, and the internal resistance of the electrode sheet 100 after forming a battery cell can be reduced.

One specific implementation is as follows:

the positive current collector adopts an aluminizer, the thickness of the insulating layer is 8 microns, the thickness of the aluminum layer is 1 micron, and the total thickness of the positive current collector is 10 microns; the negative current collector adopts a copper-plated film, the thickness of the insulating layer is 3 mu m, the thickness of the copper layer is 1 mu m, and the total thickness of the negative current collector is 5 mu m. Through the working procedures of stirring, coating, rolling, cutting and the like, active substances with the thickness of 40 mu m are coated on each surface of the positive current collector, and a pole lug groove is cleaned in a laser cleaning mode, the pole lug groove is positioned at one half of the position of a pole piece, and the size of the pole lug groove is 20mm in length and 10mm in width. And cutting a U-shaped turnover hole in a laser cutting mode, wherein the length of the U-shaped turnover hole is 6mm, and the width of the U-shaped turnover hole is 7 mm. The width of the lug is 6mm, the length of the welding end is 13mm, the lug is connected with a current collector through a rivet with the diameter of 0.5mm, and after connection is completed, battery core manufacturing is completed through procedures of packaging, baking, liquid injection, formation and the like.

Example two

On the basis of the first embodiment, the present embodiment provides a battery cell, which includes a diaphragm and a pole piece, where the diaphragm and the pole piece are stacked to form a laminated battery cell, or the diaphragm and the pole piece are wound to form a wound battery cell.

The pole piece of this embodiment has the same structure as the pole piece of the first embodiment, and can bring about the same or similar technical effects, which is not described herein again, and reference may be made to the first embodiment.

In the description of the present invention, it should be noted that unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection or a removable connection; can be mutually contacted or integrated; can be mechanically or electrically connected; either directly or indirectly through intervening media, or through the communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The terms "first" and "second" in the description and claims of the present application and the description of the above-described figures are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the utility model has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pole piece is characterized by comprising a current collector and a pole lug;

the current collector comprises an insulating layer, and a first metal layer and a second metal layer which respectively cover two opposite surfaces of the insulating layer;

the current collector comprises a first area and a second area, the second area is turned over to form a turning part, and the surface of the turning part covered with the first metal layer is opposite to the surface of the first area covered with the first metal layer; the surface of the folded part covered with the second metal layer faces to the same side as the surface of the first area covered with the first metal layer;

the first end of utmost point ear simultaneously with the cover of turning over the book portion has the surface of second metal level, and, the cover of first region has the surface laminating of first metal level.

2. The pole piece of claim 1 wherein the surface of the fold that is covered with the second metal layer is flush with at least a portion of the surface of the first area that is covered with the first metal layer.

3. The pole piece of claim 1, wherein the second end of the tab extends out of the first edge of the current collector, and the folded portion extends in a direction from the first end of the tab to the second end of the tab.

4. The pole piece of claim 3, wherein a side edge of the folded portion close to the second end of the tab is spaced from the first edge of the current collector;

the first end of utmost point ear with the folding portion, and, the mass flow body be located the folding portion with the partial laminating between the first edge.

5. The pole piece according to any one of claims 1 to 4, further comprising an active layer, wherein the active layer is coated on the surface of the current collector and avoids a pole lug groove on one side surface of the current collector; the first ends of the turnover part and the pole lugs are located in the pole lug grooves.

6. The pole piece of claim 5 wherein the folded over portion is located in a middle portion of the tab slot, the tab being located in the middle portion of the tab slot, in a direction perpendicular to a direction in which the first end of the tab is directed toward the second end of the tab.

7. The pole piece of claim 5 wherein the ratio of the width of the folded over portion to the width of the tab is in the range of 0.5 to 1.5.

8. The pole piece of claim 5, wherein the width of the pole lug slot ranges from 2mm to 30 mm;

and/or the length of the polar lug groove ranges from 2mm to 40 mm.

9. The pole piece of claim 5 wherein the sum of the thickness of the folded over portion and the thickness of the tab does not exceed the thickness of the active layer.

10. The pole piece of claim 5 wherein the tab slot is located in the range of one-third to two-thirds of the total length of the pole piece in a direction perpendicular to the first end of the tab pointing toward the second end of the tab.

11. A battery cell comprising a separator and the pole piece of any of claims 1-10, the separator and the pole piece being arranged in a stack to form a laminated cell, or the separator and the pole piece being wound to form a wound cell.