WO2022143260A1

WO2022143260A1 - Pole piece, battery comprising pole piece, and manufacturing methods

Info

Publication number: WO2022143260A1
Application number: PCT/CN2021/139654
Authority: WO
Inventors: 廖栋梁
Original assignee: 深圳信达新能源科技有限公司
Priority date: 2020-12-30
Filing date: 2021-12-20
Publication date: 2022-07-07

Abstract

The present invention relates to the technical field of batteries. Disclosed is a pole piece. The pole piece comprises current collectors, connecting bands and an active material layer; the number of the current collectors is two or more, and the connecting bands are located between adjacent current collectors. Blank areas and coating areas are formed on the current collectors; the blank areas are located at the ends of the current collectors; the blank areas are connected with the connecting bands; the active material layer is located in the coating areas. The present invention also provides a battery comprising the pole piece, a manufacturing method for the pole piece, and a manufacturing method for the battery. The present invention has the following beneficial effects: when bent, the connecting bands are prone to breaking, but when the active material layer is loaded on the connecting bands of the present invention, and the pole piece in the present invention has excellent bending performance and safety. In the present invention, when the pole piece is applied to the battery, a tab can be directly welded to the blank area of the current collector, the overall internal resistance of the battery is reduced, and the charging and discharging performance and capacity of the battery are improved. When no through hole is formed on the connecting band, the internal resistance of the battery can be reduced.

Description

A kind of pole piece, battery including pole piece and preparation method

technical field

The invention relates to the technical field of batteries, in particular to a pole piece, a battery including the pole piece, and a preparation method.

Background technique

With the development of society, portable electronic devices have brought great convenience in human life, allowing people to shield complex external noises to concentrate on doing their own things and enjoy high-quality music; for example, massagers can relieve fatigue; smart clothing , smart watches and bracelets can detect people's health data at any time, and smart clothing can bring warmth in winter and cool in summer.

At present, these portable electronic devices use traditional lithium batteries (square, cylindrical, spherical batteries) as energy storage devices. The disadvantage of these energy storage devices is that they cannot be bent, making smart watches, wristbands and headphones. The standby time is short. At present, there are also methods for improving the flexibility of batteries in the prior art. For example, the patent application with publication number CN112002933A discloses a preparation method of a flexible battery pack and the obtained flexible battery pack, and the preparation method of the battery is improved. With the development of battery technology, new energy vehicles have occupied a certain market share, and new energy vehicles reduce the benefits of fossil energy and are beneficial to the natural environment.

For example, the patent application with publication number CN112002931A discloses a preparation method of a flexible battery pack and the obtained flexible battery pack, which are arranged at intervals between adjacent single cells and fill in the gaps between adjacent single cells The encapsulant can effectively release the stress generated when the battery is repeatedly bent and folded, thereby protecting the performance of the flexible battery pack from degradation after bending. However, in the prior art, the preparation method of the battery is improved. If the structure of the electrode is improved, the preparation steps of the battery can be simplified and the mass production can be facilitated.

Patent application with publication number CN106531952A discloses a pole piece with tabs, the pole piece includes a current collector sheet, the current collector sheet is provided with a connected dressing area and a blank area, and an integral connection is partially extended on the edge of the blank area. The tab area, the tab area and the auxiliary material area are located on both sides of the blank area. However, it is difficult to maintain the performance of the pole piece after bending during use.

The patent with publication number CN103378344A is a battery pole piece and a preparation method, which can suppress the over-discharge of the battery, and at the same time can improve the over-charge capability of the battery, thereby greatly improving the cycle life of the battery in the case of over-charge and over-discharge, but in the prior art. The pole piece obtained by the preparation method of the pole piece cannot improve the bending performance and safety performance of the pole piece.

The patent application with publication number CN109830739A discloses a flexible battery and its preparation method. In the process of preparing the pole piece, a coating method is used to load the active material, but this method has the following disadvantages: First, the coating of the loading material The uniformity is poor, and the flatness of the current collector is very high, and the adverse effects are that the internal resistance of different parts of the battery is different and the rate performance of the battery is poor; When the active material is short-distance, the active material cannot be uniformly loaded on the current collector, resulting in poor electrochemical performance of the battery and a large difference in capacity from the design. The yield rate of some prepared batteries is low, and the batteries are prone to short circuits and burrs that affect the safety of the batteries; fourth, the distance between the two active materials on the current collector is small, and the device cannot reserve effective inactive materials on the current collector. The material area makes it impossible to weld the tabs on the pole piece or the welding tabs are not firm, which affects the high internal resistance and low yield of the battery.

SUMMARY OF THE INVENTION

One of the technical problems to be solved by the present invention is that the pole piece and the battery in the prior art are difficult to maintain after being bent during use, and a pole piece and a battery including the pole piece are provided.

The present invention realizes and solves the above-mentioned technical problems through the following technical means:

A pole piece, comprising a current collector, a connection band and an active material layer; the number of the current collectors is two or more, and the connection band is located between adjacent current collectors;

The current collector is provided with a blank area and a covering area, the blank area is located at the end of the current collector, the blank area is connected with the connecting tape, and the active material layer is located in the covering area.

Beneficial effect: when being bent, the connecting tape is easy to bend, but when the active material layer is not loaded on the connecting tape of the present invention, the pole piece in the present invention has excellent bending performance and safety.

When the blank area reserved on the surface of the current collector is not loaded with the active material layer, and the blank area is connected with the connecting tape, it can protect the active material layer at the edge portion from being damaged when the pole piece is packaged, and the edge is not damaged when the battery is bent. The active material of the battery is improved, and the safety of the battery is improved, so that the battery will not be short-circuited when it is bent.

When the pole piece of the present invention is used in a battery, the tabs can be directly welded to the blank area of the current collector, which can reduce the overall internal resistance of the battery and improve the charge-discharge performance and capacity of the battery. When no through holes are provided on the connecting tape, the internal resistance of the battery can be reduced.

Preferably, the number of the connecting strips is plural.

Preferably, the connecting strip is polygonal or any side of the connecting strip is arc-shaped.

Preferably, the connecting strip is in the shape of a square, a trapezoid, a rhombus, a convex polygon or a concave polygon.

Preferably, the number of the current collectors is two, and the blank area and the covering area are located at two ends of the current collector, respectively.

Preferably, one end of the current collector covering area is provided with a blank area for tab welding, and the blank area and the blank area are respectively located at two ends of the covering area.

Beneficial effects: A blank area is set at one end of the current collector covering area for welding the tabs, and no blank area is set in the second current collector covering area, which can reduce the size of the pole piece.

Preferably, the number of the current collectors is more than two, and the plurality of current collectors are arranged in a straight line or distributed in an array.

Beneficial effect: When arranged in a straight line, the number of current collectors can be set according to the length of the strap.

When distributed in an array, it can be bent and folded in multiple directions, which is especially suitable for smart clothing. During the bending process, since the current collector connected to the connecting tape is a blank area, it can protect the edge portion of the pole piece during packaging. The active material layer is not damaged, the active material at the edge is not damaged when the battery is bent, and the safety of the battery is improved at the same time, so that the battery will not be short-circuited when the battery is bent.

Preferably, the number of the current collectors is four, and the four current collectors are distributed in two rows and two columns.

Preferably, the number of the current collectors is twenty, and the twenty current collectors are distributed in four rows and five columns.

Preferably, the current collector is a copper foil, and the active material layer is a negative electrode active material layer.

Beneficial effects: when the current collector is copper foil and the active material layer is the negative electrode active material layer, the pole piece is the negative pole piece.

Preferably, the current collector is an aluminum foil, and the active material layer is a positive electrode active material layer.

Beneficial effects: when the current collector is an aluminum foil, and the active material layer is a positive electrode active material layer, the pole piece is a positive pole piece.

Preferably, the shape of the current collector is square, circle, triangle, rhombus or trapezoid.

Preferably, an active material layer is provided on the blank area.

Beneficial effects: Since the thickness of the copper foil is generally smaller than that of the aluminum foil, the positive active material layer is arranged on the blank area of the positive electrode, which can protect the edge portion from being damaged during packaging and reduce the probability of battery short circuit.

Preferably, a through hole is provided on the connecting strip.

Beneficial effects: The pole piece of the present invention has a through hole, which is suitable for various wearable electronic devices, such as watch straps, earphones, smart socks, and can reduce the weight, especially for watches and wristbands. The battery obtained by using the pole piece, The battery has a small ineffective area, which can increase the capacity of the battery. At the same time, the current collectors are connected by connecting strips. The connecting strips and the current collectors are integrally formed without welding, which can reduce the internal resistance of the battery, reduce the performance degradation of the battery, and provide a charge and discharge rate.

Preferably, the number of the through holes is multiple.

Preferably, the number of the through holes is two, three or more than four.

Preferably, the through holes are in the shape of a circle, a square, a diamond, a triangle or a trapezoid.

Beneficial effects: a through hole is provided on the connecting strap, which is suitable for straps of watches or other electronic products, and is convenient to adjust the length of the strap according to the shape of the strap.

A battery comprising the above-mentioned pole piece.

Beneficial effects: The battery in the present invention has excellent bending performance and safety performance.

Preferably, the battery includes a pole piece and a separator, and the pole piece includes a positive pole piece and a negative pole piece.

Preferably, a positive electrode active material layer is provided on the blank area of the positive electrode sheet.

Preferably, the size of the blank area of the positive pole piece is smaller than the size of the blank area of the negative pole piece.

Beneficial effect: reduce the probability of battery short circuit.

The second technical problem to be solved by the present invention lies in the fact that the pole piece and the battery obtained by the preparation method of the pole piece in the prior art have poor bending performance and safety performance, and the pole lugs can only be placed at both ends of the pole piece, providing a A method for preparing a seed pole piece and a method for preparing a battery.

The preparation method of above-mentioned pole piece, comprises the following steps:

(1) Coating or spraying the active material on the current collector;

(2) Remove the active material on the connecting belt and several blank areas of the current collector before drying, and then perform rolling after drying, or remove the active material on the blank area of the current collector and the connecting belt after drying, and then perform rolling, get pole pieces;

(3) When the active material is a negative electrode active material, the obtained pole piece is a negative electrode pole piece; when the active material is a positive electrode active material, the obtained pole piece is a positive electrode pole piece.

Beneficial effects: When the pole piece in the present invention is bent, the connecting strip is prone to bending, but since the active material loaded on the connecting strip is removed, the bending performance and safety performance of the pole piece can be improved. By using the preparation method of the present invention, a pole piece with short active material length (the length of each loading of the active material) and short blank spacing (the distance between two sections of the active material loaded on the current collector) can be efficiently prepared.

The pole piece in the present invention can directly weld the pole lug to the blank area of the current collector, which can reduce the overall internal resistance of the battery and improve the charge-discharge performance and capacity of the battery.

The present invention can uniformly load the active material on the current collector, so that the prepared battery has good electrochemical performance; the active material in the unneeded part can be conveniently recovered, thereby reducing the cost and protecting the environment.

The pole piece prepared by the method of the present invention is not prone to short circuit, burr and other phenomena, and the obtained pole piece has excellent flexibility and safety performance. When the blank area reserved on the surface of the current collector is not loaded with the active material layer, and the blank area is connected with the connecting tape, it can protect the active material layer at the edge portion from being damaged when the pole piece is packaged, and the edge is not damaged when the battery is bent. The active material of the battery is improved, and the safety of the battery is improved, so that the battery will not be short-circuited when it is bent.

The cost of using the spray method is lower than the cost of the coating method.

Preferably, the connecting tape is cut.

Preferably, the dried current collector is put into an organic solvent, and then the active material on the blank area of the current collector is wiped off.

Beneficial effects: the loading of active materials on the current collector can be completed efficiently; the preparation of pole pieces with short active material length and short blank spacing can be completed at low cost; the required pole pieces can be quickly prepared, reducing battery preparation time and cost. Cost, especially when producing small batches, has the advantage of short cycle times.

Preferably, the organic solvent includes acetone, methanol or ethanol.

Preferably, the active material is a positive active material or a negative active material.

Preferably, the preparation method of the positive electrode active material includes the following steps: mixing a positive electrode material, a binder, a conductive agent and a solvent.

Preferably, the preparation method of the negative electrode active material includes the following steps: mixing the negative electrode material, the binder, the conductive agent and the solvent.

Preferably, the cathode material includes lithium iron phosphate (LFP), lithium cobalt oxide (LCO), lithium manganate (LMO), lithium nickel manganate, nickel cobalt manganese ternary cathode material (NCM), nickel cobalt aluminum ternary One or more of positive electrode material (NCA), lithium-rich layered material, Ni(OH) ₂ , and NiO(OH).

Preferably, the negative electrode material includes one or more of artificial graphite, natural graphite, mesocarbon microspheres, carbon silicon negative electrode, lithium titanate, hydrogen storage alloy, cadmium oxide powder, and zinc flakes.

Preferably, the binder comprises polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), styrene butadiene rubber (SBR), sodium carboxymethyl cellulose (CMC-Na), polytetrafluoroethylene (PTFE) , one or more of hydroxypropyl methylcellulose (HPMC).

Preferably, the conductive agent includes one or more of carbon nanotube (CNT), carbon black (SP), graphite powder, carbon nanofiber, graphene and nickel powder.

Beneficial effect: by adopting the preparation method of the present invention, it is convenient to reserve an effective blank area on the current collector and to facilitate the welding of the tabs.

Preferably, after the cutting of the connecting tape is completed, a through hole is opened on the connecting tape.

A preparation method of a battery, comprising the following steps:

(1) adopt the preparation method of above-mentioned pole piece, obtain positive pole piece and negative pole piece respectively, the positive pole tab is welded on the positive pole piece, and the negative pole tab is welded on the negative pole piece;

(2) Then the positive pole piece, the separator and the negative pole piece are wound in turn to form a coil core or stacked to form a stacked core;

(3) The electrolyte is injected into the rolled core or the stacked core and packaged to obtain a battery.

Beneficial effects: the battery prepared by the invention has high energy density and good flexibility. The pole piece in the present invention can directly weld the pole lug to the blank area of the current collector, which can reduce the overall internal resistance of the battery and improve the charge-discharge performance and capacity of the battery.

Preferably, the electrolyte is a solid electrolyte or a liquid electrolyte.

The third technical problem to be solved by the present invention is that in the prior art, the active material is directly loaded on the pole piece by coating, thereby affecting the performance and safety of the pole piece and the battery. battery method.

A method for preparing a pole piece using a mask, comprising the following steps:

(1) Use a mask to cover the connecting belt and several blank areas, and coat or spray the active material on the covering area;

(2) drying the current collector of the coated or sprayed active material to form an active material layer, then removing the mask and rolling to obtain a pole piece;

Beneficial effects: By using the preparation method of the present invention, a pole with a short active material length (the length of each loading of the active material) and a short blank spacing (the distance between two stages of loading the active material on the current collector) can be prepared efficiently. It is convenient to reserve the part of the welding tab on the current collector.

The battery prepared by the method of the invention is not prone to short circuit, burr and other phenomena, and the prepared battery has excellent flexibility and safety performance. At the same time, the cost of using the spraying method is lower than that of the coating method.

When the pole piece in the present invention is bent, the connecting tape is easily bent, but since the active material layer is not supported on the connecting tape, the pole piece has excellent bending performance and safety.

The blank area reserved on the surface of the current collector is not loaded with the active material layer, and the blank area is connected with the connecting tape, which can protect the active material layer at the edge part from being damaged when the pole piece is packaged, and does not damage the edge at the edge when the battery is bent. Active material, while improving the safety of the battery, so that the battery will not short-circuit when bent.

Preferably, the connecting tape is cut.

Preferably, the cathode material includes lithium iron phosphate (LFP), lithium cobalt oxide (LCO), lithium manganate (LMO), lithium nickel manganate, nickel cobalt manganese ternary cathode material (NCM), nickel cobalt aluminum ternary One or more of positive electrode material (NCA), lithium-rich layered material, Ni(OH)2, and NiO(OH).

Preferably, one end of the current collector covering area is provided with a blank area for tab welding, and the blank area and the blank area are respectively located at both ends of the covering area. Overlay blank areas, connecting strips and blank areas.

Beneficial effects: By adopting the preparation method of the present invention, it is convenient to reserve an effective blank area on the current collector and to facilitate the welding of the tabs.

A method for preparing a battery using a mask, comprising the following steps:

(1) adopt the above-mentioned method for preparing pole piece using mask, obtain positive pole piece and negative pole piece respectively, positive pole tab is welded on positive pole piece, and negative pole tab is welded on negative pole piece;

Beneficial effects: the battery prepared by the invention has excellent bending performance and safety. The pole piece in the present invention can directly weld the pole lug to the blank area of the current collector, which can reduce the overall internal resistance of the battery and improve the charge-discharge performance and capacity of the battery.

Preferably, the electrolyte is a solid electrolyte or a liquid electrolyte.

The advantage of the present invention is that when the connecting tape is bent, the connecting tape is easy to bend, but when the connecting tape of the present invention is not loaded with an active material layer, the pole piece in the present invention has excellent bending performance and safety.

When the pole piece of the present invention is used in a battery, the tabs can be directly welded to the blank area of the current collector, which can reduce the overall internal resistance of the battery, improve the charging and discharging performance and capacity of the battery, and has excellent bending performance and safety performance. . When no through holes are provided on the connecting tape, the internal resistance of the battery can be reduced.

When the pole piece in the present invention is bent, the connecting strip is easily bent, but since the active material loaded on the connecting strip is removed, the bending performance and safety performance of the pole piece can be improved. By using the preparation method of the present invention, a pole piece with short active material length (the length of each loading of the active material) and short blank spacing (the distance between two sections of the active material loaded on the current collector) can be efficiently prepared.

The active material can be uniformly loaded on the current collector, so that the prepared battery has good electrochemical performance; the active material in the unneeded part can be conveniently recovered, thereby reducing the cost and protecting the environment.

The pole piece prepared by the method of the invention is less prone to short circuit, burr and other phenomena, and the prepared pole piece has excellent flexibility and safety performance.

Description of drawings

1 is a schematic structural diagram of a pole piece in Embodiment 1 of the present invention;

2 is a schematic structural diagram of a pole piece in Embodiment 2 of the present invention;

3 is a schematic structural diagram of a pole piece in Embodiment 3 of the present invention;

4 is a schematic structural diagram of a positive pole piece in Embodiment 5 of the present invention;

5 is a schematic structural diagram of a negative pole piece in Embodiment 5 of the present invention;

6 is a schematic structural diagram of a pole piece in Embodiment 6 of the present invention;

7 is a schematic structural diagram of a pole piece in Embodiment 7 of the present invention;

8 is a schematic structural diagram of a pole piece in Embodiment 8 of the present invention;

9 is a schematic structural diagram of a pole piece in Embodiment 9 of the present invention;

10 is a schematic structural diagram of a pole piece in Embodiment 10 of the present invention;

11 is a schematic structural diagram of a pole piece with a through hole in Embodiment 13 of the present invention;

12 is a schematic structural diagram of a pole piece with a through hole in Embodiment 14 of the present invention;

13 is a schematic structural diagram of a pole piece with a through hole in Embodiment 15 of the present invention;

14 is a schematic structural diagram of a pole piece with a through hole in Embodiment 16 of the present invention;

15 is a schematic structural diagram of a pole piece with a through hole in Embodiment 17 of the present invention;

16 is a schematic structural diagram of a pole piece with a through hole in Embodiment 18 of the present invention;

17 is a schematic structural diagram of a pole piece with a through hole in Embodiment 19 of the present invention;

18 is a schematic structural diagram of a pole piece with a through hole in Embodiment 20 of the present invention;

19 is a schematic structural diagram of a mask in Embodiment 27 of the present invention;

20 is a schematic structural diagram of a mask in Embodiment 29 of the present invention;

In the figure: collector 11; first collector 111; second collector 112; blank area 12; first blank area 121; second blank area 122; covering area 13; first covering area 131; second covering area material area 132; connecting belt 14; blank area 15; through hole 16.

Detailed ways

In order to make the purposes, 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 in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the present invention. examples, but not all examples. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The test materials and reagents used in the following examples can be obtained from commercial sources unless otherwise specified.

If the specific technology or condition is not indicated in the embodiment, it can be carried out according to the technology or condition described in the literature in this field or according to the product specification.

Example 1

A pole piece, as shown in FIG. 1 , includes a current collector 11, a connecting belt 14 and an active material layer (not shown). The current collector 11 is provided with a blank area 12 and a covering area 13. In this embodiment, the current collector The number of 11 is two.

The current collector 11 includes a first current collector 111 and a second current collector 112. In this embodiment, the shapes of the first current collector 111 and the second current collector 112 are square but not limited to a square, or a circle, a triangle, a diamond or Trapezoid, the connecting strip 14 is located between the first current collector 111 and the second current collector 112 , in order to reduce the process, the connecting strip 14 is integrally formed with the first current collector 111 and the second current collector 112 in this embodiment.

Both ends of the first current collector 111 are respectively provided with a first blank area 121 and a first covering area 131, the first blank area 121 is rectangular, the first covering area 131 is square, and the size of the first blank area 121 is smaller than that of the first blank area 121. A covering area 131 , the first blank area 121 is connected with the connecting belt 14 .

Two ends of the second current collector 112 are respectively provided with a second blank area 122 and a second covering area 132, the second blank area 122 is rectangular, the second covering area 132 is square, and the size of the second blank area 122 is smaller than the size of the second blank area 122. The second covering area 132 and the second blank area 122 are connected with the connecting belt 14 . In this embodiment, the first blank area 121 , the connecting strip 14 and the second blank area 122 are H-shaped, and the connecting strip 14 is square.

The active material layers cover the first coating region 131 and the second coating region 132, respectively.

In order to facilitate the welding of the tabs, one end of the first covering area 131 or one end of the second covering area 132 is provided with a blank area 15, and the blank area 15 is integrally formed with the first current collector 111 or the second current collector 112, leaving the blank area 15. The white area 15 and the first blank area 121 are respectively located at both ends of the first covering area 131 , or the blank area 15 and the second blank area 122 are respectively located at both ends of the second covering area 132 .

In this embodiment, the pole piece includes a positive pole piece and a negative pole piece. When the first current collector 111 and the second current collector 112 are both copper foils, the active material layer is the negative electrode active material layer, wherein the negative electrode active material layer is the existing technology, the pole piece is the negative pole piece at this time.

When the first current collector 111 and the second current collector 112 are both aluminum foils, the active material layer is a positive electrode active material layer, wherein the positive electrode active material layer is the prior art, and the pole piece is a positive pole piece.

The first current collector 111 and the second current collector 112 are both copper foils, and the active material layer is a negative electrode active material layer, wherein the negative electrode active material layer is the prior art, and the pole piece is a negative pole piece at this time.

The advantage of this embodiment is that the connecting strip 14 is easily bent when being bent, but since the active material layer is not loaded on the connecting strip 14, the pole piece has excellent bending performance and safety.

The blank area 12 reserved on the surface of the current collector 11 is not loaded with the active material layer, and the blank area 12 is connected with the connecting tape 14, which can protect the active material layer at the edge portion from being damaged when the pole piece is packaged, and is not damaged when the battery is bent. Active material at the edge, while improving the safety of the battery, so that the battery will not short-circuit when bent.

Example 2

The difference between this embodiment and Embodiment 1 is that, as shown in FIG. 2 , the number of current collectors 11 is greater than two, and the plurality of current collectors 11 are distributed in an array. In this embodiment, the number of current collectors 11 is four, and the four current collectors 11 are distributed in two rows and two columns.

Example 3

The difference between this embodiment and Embodiment 2 is that as shown in FIG. 3 , the number of current collectors 11 is twenty, and the twenty current collectors 11 are distributed in four rows and five columns.

The advantage of this embodiment is that bending and folding in multiple directions can be achieved, which is especially suitable for smart clothing. During the bending process, since the current collector 11 connected to the connecting strip 14 is a blank area 12, the current collector 11 connected to the connecting strip 14 can be used in the packaging of the pole piece. The active material layer at the edge portion is protected from being damaged, the active material at the edge is not damaged when the battery is bent, and the safety of the battery is improved, so that the battery will not be short-circuited when the battery is bent.

Example 4

The difference between this embodiment and the above-mentioned embodiment is that a positive electrode active material layer is provided on the blank area of the positive electrode plate.

The advantage of this embodiment is that since the thickness of the copper foil is generally smaller than that of the aluminum foil, the positive electrode active material layer is arranged on the blank area of the positive electrode plate, which can protect the edge portion from being damaged during packaging, and at the same time reduce the probability of short circuit of the battery.

Example 5

The difference between this embodiment and the above-mentioned embodiment is: as shown in Figures 4 and 5, the left side of the figure is the positive pole piece, the right side of the figure is the negative pole piece, and the size of the blank area of the positive pole piece is smaller than the blank of the negative pole piece area size.

The advantage of this embodiment is that the probability of short circuit of the battery can be reduced.

Example 6

The difference between this embodiment and Embodiment 1 is that, as shown in FIG. 6 , the first blank area 121 , the connecting strip 14 and the second blank area 122 are in a square shape.

Example 7

The difference between this embodiment and Embodiment 1 is that, as shown in FIG. 7 , the connecting belt 14 is in a trapezoidal shape. The shape and number of the connecting belts 14 can be combined arbitrarily.

Example 8

The difference between this embodiment and Embodiment 1 is that: as shown in FIG. 8 , the number of connecting straps 14 is multiple, and the number of connecting straps 14 in this embodiment is two, but not limited to two. The shape and number of the connecting belts 14 can be combined arbitrarily.

Example 9

The difference between this embodiment and Embodiment 1 is that, as shown in FIG. 9 , the connecting strip 14 is in a dodecagon shape. The shape and number of the connecting belts 14 can be combined arbitrarily.

Example 10

The difference between this embodiment and Embodiment 1 is that as shown in FIG. 10 , the connecting strip 14 is rectangular, wherein both sides of the connecting strip 14 are arc-shaped, and the bending direction of the arc is set according to actual needs. The shape and number of the connecting belts 14 can be combined arbitrarily.

Example 11

The difference between this embodiment and Embodiment 1 is that an active material layer is provided on the blank area 12 .

Example 12

The difference between this embodiment and Embodiment 2 is that one or seven of the blank areas 12 are provided with an active material layer.

Example 13

A pole piece with a through hole, the difference between this embodiment and the first embodiment is: as shown in FIG. 11 , a through hole 16 is opened in the center of the connecting belt 14, and the number and size of the through hole 16 are set according to actual needs. , the shape of the through hole in this embodiment is a circle, but not limited to a circle, and may be a square, a rhombus, a triangle or a trapezoid.

Beneficial effects of this embodiment: The pole piece in this embodiment is suitable for various wearable electronic devices, and the connecting strap of the pole piece has a through hole 16, which is especially suitable for watch straps of various watches or other electronic products. The battery obtained from the sheet has less battery inactive area, which can increase the capacity of the battery. At the same time, the current collectors 11 are connected by the connecting belt 14, and the connecting belt 14 and the current collector 11 are integrally formed without welding, which can reduce the internal resistance of the battery. At the same time, the pole piece has excellent bending performance and safety.

Example 14

The difference between this embodiment and Embodiment 13 is that, as shown in FIG. 12 , the number of current collectors 11 is three, and the three current collectors 11 are arranged in a straight line.

The beneficial effect of this embodiment: the number of current collectors 11 can be set according to the length of the watch band.

Example 15

The difference between this embodiment and Embodiment 14 is that, as shown in FIG. 13 , the first blank area 121 , the connecting strip 14 and the second blank area 122 are H-shaped.

Example 16

The difference between this embodiment and Embodiment 15 is: as shown in FIG. 14 , the connecting strip 14 is in the shape of a trapezoid, and the through hole 16 in this embodiment is in the shape of a circle, but it is not limited to a circle, and can be a square, a diamond, a triangle or trapezoid. The shape and number of the connecting strips 14 and the shape and number of the through holes 16 can be arbitrarily combined.

Example 17

The difference between this embodiment and Embodiment 15 is that: as shown in FIG. 15 , the number of connecting belts 14 is multiple, and the number of connecting belts 14 in this embodiment is two, but not limited to two. A through hole 16 is formed on one of the connecting strips 14 in the embodiment, and the through hole 16 is circular, but not limited to a circular shape, and may be a square, a rhombus, a triangle or a trapezoid. The shape and number of the connecting strips 14 and the shape and number of the through holes 16 can be arbitrarily combined.

Example 18

The difference between this embodiment and Embodiment 17 is that: as shown in FIG. 16 , through holes 16 are formed on the two connecting strips 14 . In this embodiment, one through hole 16 is circular, and the other through hole 16 is triangular. , the shape and number of the connecting strips 14 and the shape and number of the through holes 16 can be arbitrarily combined.

Example 19

The difference between this embodiment and Embodiment 15 is: as shown in FIG. 17 , the connecting strip 14 is dodecagonal, the number of through holes 16 in this embodiment is two, and the through holes 16 are square, but not only Limited to square, can be circle, rhombus, triangle or trapezoid. The shape and number of the connecting strips 14 and the shape and number of the through holes 16 can be arbitrarily combined.

Example 20

The difference between this embodiment and Embodiment 15 is: as shown in FIG. 18 , the connecting strip 14 is rectangular, wherein both sides of the connecting strip 14 are arc-shaped, and the bending direction of the arc is set according to actual needs. The through hole 16 has a square shape, but is not limited to a square shape, and can be a circle, a diamond, a triangle or a trapezoid. The shape and number of the connecting strips 14 and the shape and number of the through holes 16 can be arbitrarily combined.

Example 21

The difference between this embodiment and Embodiment 13 is that an active material layer is provided on the blank area 12 .

Example 22

The difference between this embodiment and Embodiment 14 is that an active material layer is provided on one or three of the blank areas 12 .

Example 23

This embodiment provides a battery, the battery includes a positive pole piece, a separator and a negative pole piece, the positive pole piece, the separator and the negative pole piece are wound or stacked in sequence, and the shape of the separator corresponds to the shape of the positive pole piece and the negative pole piece, The positive pole piece or the negative pole piece is the positive pole piece or the negative pole piece in any one of Embodiments 1 to 22.

Example 23

The method for preparing the pole piece in the above embodiment, taking Example 1 as an example, and using the obtained pole piece to prepare a battery, specifically includes the following steps:

The preparation method of the positive pole piece comprises the following steps:

(1) Preparation of positive active material: In an argon-protected glove box, using lithium cobalt oxide as the positive electrode material, weigh 47.5 g of lithium cobalt oxide (LCO), 1 g of polyvinylidene fluoride (PVDF), and 1 g of carbon Black (SP), 0.5g of carbon nanotubes (CNT) and 25g of N-methylpyrrolidone (NMP) are mixed and dispersed to obtain a positive electrode active material; the positive electrode active material in this embodiment can also use the prior art Other cathode active materials in;

(2) Using the aluminum foil as the current collector 11, a coating machine is used to coat the positive electrode active material on the current collector 11. Before drying, remove the positive electrode active material on all blank areas and connecting strips, in order to facilitate the welding of the positive electrode tabs, At the same time, the positive active material on the blank area was removed, and then the aluminum foil was dried at 80 °C for 24 hours to form a positive active material layer;

(3) In this embodiment, according to FIG. 1 , the rolled current collector 11 is cut to form the connecting strip 14 , that is, the positive pole piece is obtained; it may not be cut.

The preparation method of the negative pole piece comprises the following steps:

(1) In an argon-protected glove box, using artificial graphite as the negative electrode material, weigh 23.5 g of artificial graphite, 0.375 g of sodium carboxymethyl cellulose (CMC-Na), and 0.625 g of styrene-butadiene rubber (SBR). ), 0.5g of carbon black (SP) and 12.5g of deionized water were mixed and dispersed to obtain the negative electrode active material;

(2) Using the copper foil as the current collector 11, the copper foil coated with the negative electrode active material was dried at 80°C for 24 hours to form the negative electrode active material layer, and then the current collector 11 was put into acetone to reduce the adhesion of the negative electrode active material layer. , and then erase the negative electrode active material on the blank area and the connecting tape, in order to facilitate the welding of the positive electrode tab, at the same time erase the negative electrode active material on the blank area;

(3) In this embodiment, according to FIG. 1 , the rolled current collector 11 is cut to form a connecting belt, that is, a negative pole piece is obtained; it may not be cut.

In this embodiment, the active material is removed before drying during the preparation of the positive electrode piece, but the active material can also be removed after drying. The active material is removed after drying during the preparation of the negative pole piece, and it is also possible to remove the active material before drying.

The preparation method of the battery includes the following steps:

(1) the positive electrode tab is welded on the blank area 15 of the positive pole piece, and the negative electrode tab is welded on the blank area 15 of the negative pole piece;

(3) The liquid electrolyte is injected into the roll core or the stacked core, and the first encapsulation is carried out, then the aging and chemical formation are carried out, and finally the second encapsulation is carried out, that is, the battery is obtained.

When the electrolyte is a solid electrolyte, the solid electrolyte is loaded between the positive electrode and the negative electrode.

Example 24

The difference between this example and Example 23 is that a sprayer is used to spray the positive electrode active material or the negative electrode active material on the current collector.

Example 25

The difference between this embodiment and the 23rd embodiment is that after the cutting of the connecting tape 14 is completed, a hole punch or other device in the prior art is used to open the through hole 16 on the connecting tape. The number of through holes is set according to actual needs. In this embodiment, the shape of the through holes 16 is a circle, but not limited to a circle, or a square, a diamond, a triangle, or a trapezoid.

Example 26

The difference between this embodiment and Embodiment 23 is that only the active material layer on the first blank area 121 or the second blank area 122 is removed during the preparation of the positive electrode piece.

During the preparation of the negative pole piece, only the active material layer on the first blank area 121 or the second blank area 122 is removed.

Example 27

The method for preparing the pole piece in the above embodiment by using a mask, taking Example 1 as an example, and using the obtained pole piece to prepare a battery, the method specifically includes the following steps:

(2) Using the aluminum foil as the current collector 11, a mask is used to cover the connecting strip 14, the first blank area 121 and the second blank area 122. In order to facilitate the welding of the positive electrode tabs, the mask also covers the blank area in this embodiment. 15. Use a coating machine to coat the positive active material on the coating area 13, and dry the aluminum foil coated with the positive active material at 80°C for 24 hours to form the positive active material layer. The shape of the mask in this example is shown in Figure 19 As shown, the shaded part in FIG. 19 represents the hollow part, and the mask in this embodiment can also adopt other shapes, as long as the connecting tape 14, the first blank area 121 and the second blank area 122 can be covered;

(3) Then remove the mask for rolling;

(4) In the present embodiment, the rolled current collector 11 is cut to form the connecting belt 14 according to FIG. 1 to obtain a positive pole piece; it is also possible to obtain a positive pole piece without cutting;

(5) Check the morphology of the positive pole piece and measure the areal density. The areal density is 40 mg/m ² , and the measured areal density is within the required range.

(2) Using the copper foil as the current collector 11, a mask is used to cover the connecting strip 14, the first blank area 121 and the second blank area 122. In order to facilitate the welding of the negative electrode tabs, the mask plate also covers the blanks in this embodiment. In zone 15, a coating machine is used to coat the negative electrode active material on the coating zone 13, and the copper foil coated with the negative electrode active material is dried at 80°C for 24 hours to form the negative electrode active material layer. The masks have the same shape in Example 1;

(3) Then remove the mask for rolling;

(4) In this embodiment, the rolled current collector 11 is cut to form a connecting belt according to FIG. 1, that is, a negative pole piece is obtained; it is also not necessary to cut it;

(5) Check the morphology of the negative pole piece and measure the areal density. The areal density is 20 mg/m ² , and the measured areal density is within the required range.

The preparation method of the battery includes the following steps:

(1) the positive pole tab is welded on the blank area 15 of the positive pole piece, and the negative pole tab is welded on the blank area 15 of the negative pole piece;

Example 28

The difference between this example and Example 27 is that the positive electrode active material is sprayed on the coating area ¹³ by a spraying machine, the morphology of the positive electrode pole piece is checked and the areal density is measured. Density is within the required range.

The negative electrode active material was sprayed on the coating area 13 by a spraying machine, the morphology of the negative electrode pole piece was checked and the areal density was measured. The areal density was 20 mg/m ² , and the measured areal density was within the required range.

Example 29

Using the mask to prepare the pole piece in Example 2, the method in Example 27 is used, the difference is that the shape of the mask is adjusted, as shown in Figure 20, so that the shape of the mask is the same as the shape of the pole piece. The shape corresponds, and the shaded filled part in Figure 20 is a hollow part.

Example 30

The difference between this embodiment and the 27th embodiment is that after the connecting tape 14 is cut, a hole punch or other device in the prior art is used to open the through hole 16 on the connecting tape. The number of through holes is set according to actual needs. In this embodiment, the shape of the through holes 16 is a circle, but not limited to a circle, or a square, a diamond, a triangle, or a trapezoid.

Example 31

The difference between this embodiment and Embodiment 27 is that the number of connecting strips 14 is multiple. In this embodiment, the number of connecting strips 14 in the positive pole piece and the negative pole piece is two. , separator and negative pole piece are wound in turn to form a core. In the preparation process of the pole piece in this embodiment, the connecting tape is cut.

The battery obtained in Example 31 was subjected to a 5050 bending test experiment (5000 times of bending, 50 times of 180° folding). During the experiment, the capacity was measured when bending 505 times, 2020 times, and 5050 times respectively. When measuring, first charge the voltage of the battery to 4.20, and then measure the capacity (using the battery performance test system of Shenzhen Newwell Electronics Co., Ltd.).

Bending test method: The first step is to bend the right half of the battery 60° counterclockwise and the left half of the battery 60° clockwise; the second step, bend the right half of the battery counterclockwise Fold 60° and bend the left half of the battery 60° counterclockwise at the same time; in the third step, repeat the bending test method, and perform a 180° folding test after every 100 bending tests. In this way, 5000 bending tests and 50 folding tests are repeated. A total of 5050 tests were performed. The test results are shown in Table 1.

Table 1 is the measurement result of the battery in Example 31

By analyzing the bending test data, five battery samples were obtained after 5050 times of bending test, the capacity of the five groups of batteries was maintained above 99%, and the average capacity retention rate was above 99.9%. In addition, after the cycle performance test of the battery bent for 5050 times, the battery has good cycle performance.

The above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The recorded technical solutions are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

A pole piece, characterized in that: it comprises a current collector, a connecting band and an active material layer; the number of the current collectors is two or more, and the connecting band is located between adjacent current collectors;

The current collector is provided with a blank area and a covering area, the blank area is located at the end of the current collector, the blank area is connected with the connecting tape, and the active material layer is located in the covering area.
The pole piece according to claim 1, wherein the number of the current collectors is two, and the blank area and the covering area are located at two ends of the current collector, respectively.
The pole piece according to claim 1, wherein the number of the current collectors is more than two, and the plurality of current collectors are arranged in a straight line or distributed in an array.
The pole piece according to claim 1, wherein: one end of the current collector covering area is provided with a blank area for the tab welding, and the blank area and the blank area are respectively located at both ends of the covering area .
The pole piece according to claim 1, wherein the number of the connecting strips is plural.
The pole piece according to claim 5, wherein the connecting strip is polygonal or any side of the connecting strip is arc-shaped.
The pole piece according to claim 1, wherein an active material layer is provided on the blank area.
The pole piece according to claim 7, wherein the size of the blank area of the positive pole piece is smaller than the size of the blank area of the negative pole piece.
The pole piece according to any one of claims 1-8, characterized in that: the connecting strip is provided with a through hole.
The pole piece according to claim 9, wherein the through hole is in the shape of a circle, a square, a rhombus, a triangle or a trapezoid.
A battery comprising the pole piece of any one of claims 1-10.
The method for preparing the pole piece as described in any one of claims 1-10, is characterized in that: comprising the following steps:

(1) Coating or spraying the active material on the current collector;

(2) Remove the active material on the connecting belt and several blank areas of the current collector before drying, and then perform rolling after drying, or remove the active material on the blank area of the collector and the connecting belt after drying, and then perform rolling, get pole pieces;

(3) When the active material is a negative electrode active material, the obtained pole piece is a negative electrode pole piece; when the active material is a positive electrode active material, the obtained pole piece is a positive electrode pole piece.
The method for preparing the pole piece as described in any one of claims 1-10 by using a mask, is characterized in that: comprising the following steps:

(1) Use a mask to cover the connecting belt and several blank areas, and coat or spray the active material on the covering area;

(2) drying the current collector coated or sprayed with the active material to form an active material layer, and then removing the mask for rolling to obtain a pole piece;

(3) When the active material is a negative electrode active material, the obtained pole piece is a negative electrode pole piece; when the active material is a positive electrode active material, the obtained pole piece is a positive electrode pole piece.
A method for preparing a battery, comprising the following steps:

(1) adopt the method described in claim 12 or claim 13 to make positive pole piece and negative pole piece respectively, the positive pole tab is welded on the positive pole piece, and the negative pole tab is welded on the negative pole piece;

(2) Then the positive pole piece, the separator and the negative pole piece are wound in turn to form a coil core or stacked to form a stacked core;

(3) The electrolyte is injected into the rolled core or the stacked core and packaged, that is, a battery is obtained.