CN115528211A

CN115528211A - Pole piece for lithium ion battery and lithium ion battery

Info

Publication number: CN115528211A
Application number: CN202211279896.2A
Authority: CN
Inventors: 阙小超; 杨国平; 王丽; 敖万千
Original assignee: Yuantuo Microelectronics Technology Ningbo Co ltd
Current assignee: Yuantuo Microelectronics Technology Ningbo Co ltd
Priority date: 2022-10-19
Filing date: 2022-10-19
Publication date: 2022-12-27
Anticipated expiration: 2042-10-19
Also published as: CN115528211B

Abstract

The invention discloses a pole piece for a lithium ion battery and the lithium ion battery, wherein the pole piece for the lithium ion battery comprises a current collector and a conducting layer coated on the surface of the current collector, the thickness of the pole piece is 20-4000 micrometers, and the conducting layer comprises the following components: 80.0 to 98.5wt.% active material; 0.1 to 10wt.% of a dot-or planar conductive material; 0.01 to 5.0wt.% of a linear conductive agent; 0.2 to 10wt.% binder. The invention uses the electrode formula with high active substance content, reduces the weight and volume ratio of inactive materials, and obviously improves the energy density of the battery compared with the prior product. On the premise of ensuring the unchanged endurance of the electronic product, the weight and the volume of the battery are greatly reduced; on the premise of ensuring that the volume of the battery is not changed, the endurance time of the product can be greatly improved.

Description

Pole piece for lithium ion battery and lithium ion battery

Technical Field

The invention relates to the field of battery manufacturing, in particular to a pole piece for a lithium ion battery and the lithium ion battery.

Background

The existing battery comprises two typical structures, namely a winding type structure battery and a laminated type structure battery, wherein the winding type structure battery is internally assembled by a positive electrode, a diaphragm and a negative electrode with certain lengths in a winding mode, and the number of winding layers is generally different from several layers to dozens of layers; the laminated structure battery is internally assembled by a plurality of independent positive pole pieces and negative pole pieces in a laminating mode, the positive pole pieces and the negative pole pieces are separated by continuous diaphragm layers, and the number of the positive pole pieces and the negative pole pieces is several to dozens of pieces.

In the manufacturing process, links such as electrode manufacturing, battery core assembly and the like are long in process, low in efficiency and high in cost. The slurry preparation of the anode and cathode materials needs to use an organic solvent and deionized water, and the coating process of the anode and cathode slurry needs to remove the solvent, which consumes a large amount of electric power. The coating thickness of the positive and negative pole pieces is less than or equal to 200um, and the single-side capacity is less than or equal to 4mAh/cm ² When assembling, a large number of or long flaky positive and negative electrodes need to be alternately and repeatedly combined, so that the designed size and capacity are achieved. The pole piece is in the manufacturing process pollutant such as burr, dust form more little short circuit points easily, therefore battery reliability and qualification rate also can receive the influence.

In addition, because the active coatings of the positive pole piece and the negative pole piece are thin, copper and aluminum foil current collectors are used for each layer, the positive pole piece and the negative pole piece are isolated by diaphragms, holes in the diaphragms are filled with electrolyte after being injected with the electrolyte, and the inactive materials occupy more volume and weight in the battery, so that the proportion of the active materials is reduced. As such, the battery energy density may be limited, affecting the end product endurance and user experience.

Disclosure of Invention

In order to overcome the above disadvantages, the present invention provides a lithium ion battery and a pole piece for the lithium ion battery, wherein the lithium ion battery reduces the usage amount of a current collector, a diaphragm and an electrolyte, and can use more active materials in unit volume/weight, thereby significantly improving the energy density (Wh/kg and Wh/L) of the lithium ion battery and the endurance time of a terminal product, solving the problems of low energy density, long production flow and low efficiency of the conventional small lithium ion battery, greatly reducing the complexity of the production flow, significantly improving the efficiency, and reducing the battery cost.

In order to achieve the above purposes, the invention adopts the technical scheme that: the utility model provides a pole piece for lithium ion battery, the pole piece includes the mass flow body and coats the conducting layer on the mass flow body surface, pole piece thickness is 20 ~ 4000um, the conducting layer includes following component: 80.0 to 98.5wt.% active material; 0.1 to 10wt.% of a dot-or planar conductive material; 0.01 to 5.0wt.% of a linear conductive agent; 0.2 to 10wt.% binder. The current collector of the positive pole piece is selected from any one of an aluminum foil, an aluminum mesh and a perforated aluminum foil, the thickness of the current collector is 5-100 micrometers, one or two surfaces of the current collector can be coated with a layer of conductive adhesive, the conductive adhesive is selected from polyacrylic acid and conductive carbon, the thickness of the coating is 0.2-5 micrometers, and the layer of conductive adhesive can help to reduce contact resistance and improve the multiplying power performance of the battery. The current collector of the negative pole piece is selected from any one of copper foil, copper mesh and copper foil with holes, the thickness is 4-50um, one side or two sides of the current collector can be coated with a layer of conductive adhesive, the conductive adhesive is selected from polyacrylic acid and conductive carbon, the thickness of the conductive adhesive layer is 0.2-5 um, and the layer of conductive adhesive can help to reduce contact resistance and improve the multiplying power performance of the battery.

Preferably, the pole piece comprises a positive pole piece, and the active material in the conducting layer of the positive pole piece is selected from any one or a mixture of lithium cobaltate, lithium nickel cobalt manganese oxide, lithium iron phosphate, lithium manganese oxide and lithium manganese iron phosphate;

the dot or planar conductive material is selected from any one or a mixture of more of carbon black, flake graphite and graphene;

the linear conductive agent is selected from any one or a mixture of two of carbon nanotube CNT and carbon fiber;

the binder is selected from one or more of Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyacrylic acid (PAA) and Hydrogenated Nitrile Butadiene Rubber (HNBR).

Preferably, the pole piece comprises a negative pole piece, and the active material in the conducting layer of the negative pole piece is selected from graphite, hard carbon, soft carbon, silicon and oxide SiO of silicon _x Lithiated SiO _x -Li _y SiO _x Any one or more of graphite and silicon mixture, metallic lithium and lithium titanate;

the point or planar conductive material is carbon black;

the linear conductive agent is selected from carbon nano tubes or carbon fibers;

the binder is selected from any one or a mixture of more of sodium carboxymethylcellulose (CMC), styrene Butadiene Rubber (SBR), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyacrylic acid (PAA) and Hydrogenated Nitrile Butadiene Rubber (HNBR).

Preferably, the conductive layer further comprises an oxide solid electrolyte to increase ion transmission rate, the content of the oxide solid electrolyte is 0.1 to 15wt%, and the oxide solid electrolyte is selected from LATP-Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ 、LLZO-Li _6.4 La ₃ Zr _1.4 Ta _0.6 O ₁₂ Any one of them.

Preferably, for improving pole piece lithium ion conductivity, be provided with a plurality of through-holes on the pole piece, it is a plurality of the through-hole distributes along pole piece thickness direction and/or perpendicular pole piece thickness direction, the through-hole diameter is 0.01um ~ 100um, and adjacent through-hole interval is 0.02 ~ 0.5mm. Furthermore, the diameter of the holes uniformly distributed in the pole piece along the thickness direction is 0.01-100 um, the distance between the through holes is 0.05-0.5 mm, and the through holes penetrate through the thickness of the whole pole piece. The diameter of the cavity is 0.01-100 um, and the distance between the holes is 0.02-0.1 mm.

Preferably, the pole piece is formed by compounding a plurality of layers of diaphragms, and the diaphragms are formed by pressing an active material, a point or plane conductive material, a linear conductive agent and a binder in a rolling mode. And a transition layer is arranged between the diaphragms and is used for improving the electronic and ionic conductivity of the pole piece. The thickness of the membrane is 50-500 um, and the thickness of the transition layer is 5-25 um. The transition layer comprises any one or a mixture of the following components, and the composition of the transition layer comprises:

1) The aluminum foil or the aluminum mesh with holes is 5-25 um thick, the surface of the aluminum foil or the aluminum mesh is coated with a conductive layer or a conductive sublayer, such as solid electrolyte materials LATP, LLZO and the like, and the thickness of the conductive layer or the conductive sublayer is not more than 5um; the aluminum foil or the aluminum net can also be provided with a leading-out tab and is welded on the positive tab in parallel;

2) An electronic conducting layer composed of a conducting agent and a binder, wherein the conducting agent is selected from any one of conductive carbon black, carbon nanotubes and graphene;

3) A conductive sublayer consisting of a solid electrolyte or polymer electrolyte (e.g., PEO, etc.);

4) An intermediate layer having dual functions of electron conduction and ion conduction;

5) The middle layer with capacitance property is composed of activated carbon, conductive agent and binder.

Preferably, one side of each pole piece, which faces to the adjacent pole piece, is provided with a metal lithium foil layer or a metal lithium sheet layer, the thickness of the metal lithium foil layer or the metal lithium sheet layer is 20-1000 um, and the metal lithium foil layer or the metal lithium sheet layer has the same shape and the same area with the pole pieces. Because active lithium consumption brought by a solid electrolyte membrane (SEI) formed on the surface of the negative active material is reduced, the irreversible capacity loss of the battery in the first charging and discharging process is reduced by arranging a layer of metal lithium foil on one side of the positive pole piece, which faces the negative pole piece, or arranging a metal lithium foil/metal lithium sheet layer on one side of the negative pole piece, which faces the positive pole piece, so as to improve the first charging and discharging efficiency of the battery, especially when the negative pole is a silicon negative pole or a silicon-carbon composite negative pole. Because the metal lithium is soft, the metal lithium foil layer or the lithium sheet layer can be firstly pasted on the surface of the positive pole piece or the negative pole piece before the battery is assembled.

Preferably, the lithium metal foil layer or the lithium sheet layer is provided with pores, the porosity is 1-80%, and the diameter of the pores is 0.05-2 mm.

A lithium ion battery comprises a positive pole piece, a negative pole piece and a diaphragm, wherein the positive pole piece and/or the negative pole piece are/is the pole pieces for the lithium ion battery.

Preferably, the number of the positive pole piece, the negative pole piece and the diaphragm is one.

Preferably, diaphragm thickness is 5 ~ 250um, positive pole piece thickness is 40 ~ 4000um, negative pole piece thickness is 20 ~ 3000um.

Preferably, the button comprises a button shell arranged outside the positive pole piece and the negative pole piece, the diaphragm and the positive pole piece are arranged from the bottom of the button shell to the top in sequence, the diameter of the positive pole piece is 5-20 mm, and the diameter of the diaphragm is 6-22 mm; the diameter of the negative pole piece is 5.6-21 mm, the diameter of the button shell is 6.1-22.1 mm, the thickness is 0.05-0.2 mm, the button shell further comprises an insulating sleeve arranged between the button shell and the pole piece, the height of the insulating sleeve = the thickness of the positive pole piece plus the thickness of the diaphragm plus the thickness of the negative pole piece plus or minus 0.2mm, the button shell further comprises a top cover arranged above the positive pole piece, the diameter of the top cover is 5-21 mm, and the thickness is 0.05-0.2 mm. During the assembly, the negative pole piece is placed into the button firstly, then the diaphragm, the positive pole piece and the insulating sleeve are placed in sequence, at the moment, the negative pole is required to be ensured to completely cover the positive pole piece and the insulating sleeve, then, electrolyte is added, the electrolyte amount is not less than the sum of the internal pore volumes of the electrode and the diaphragm, and finally, the top cover is installed for sealing.

Wherein: the diaphragm is selected from one or more of PP, PE, PET, PI, non-woven fabrics diaphragm and aramid fiber diaphragm, the porosity is 30-75%, the thickness is 5-50 microns, wherein one or two surfaces of the basal membrane can be coated with Al with the thickness of 1-5 microns ₂ O ₃ Or a boehmite ceramic coating; solid electrolyte separator layers (porosity) may also be employed<10%) thickness<250 microns; a layer of solid electrolyte (LATP, LLZO and the like) can be sprayed on the surface of the negative pole piece in a spraying and transfer coating mode, and the thickness is 6-30 mu m.

The insulating sleeve needs to be electrically insulating and resistant to electrolyte corrosion. The insulating sleeve is made of any one of PP, PI and PET, and the thickness of the insulating sleeve is 0.02-0.5 mm.

Preferably, a metal sheet is arranged on one side of the positive pole piece, which is far away from the negative pole piece, and/or on one side of the negative pole piece, which is far away from the positive pole piece, the metal sheet is made of aluminum foil or copper foil, the thickness of the metal sheet is 5 um-25 um, and the diameter of the metal sheet is consistent with that of the positive pole piece or the negative pole piece. Active lithium consumption brought by a solid electrolyte film (SEI film) formed on the surface of the negative active material is reduced by one side of the positive pole piece far away from the negative pole piece and/or a metal sheet arranged on the negative pole piece far away from the positive pole piece, so that the irreversible capacity loss of the battery in the first charge-discharge process is reduced, the first charge-discharge efficiency of the battery is improved, and particularly when the negative pole piece is a silicon-containing negative pole (Gr + SiO) _x 、Gr+Li _y SiO _x 、Gr+Si、Si、Li _y SiO _x Etc.). Since the metallic lithium is soft, the metallic lithium can be attached to the surface of the negative electrode before the battery is assembled.

Preferably, one or two surfaces of the metal sheet are coated with a layer of conductive adhesive, the thickness of the conductive adhesive coating is 0.2-5 um, and the conductive adhesive is selected from polyacrylic acid and conductive carbon. The conductive adhesive can help to reduce the contact resistance between the positive pole piece and the top cover and improve the multiplying power performance of the battery.

Preferably, the surface of one side, close to the top cover, of the positive pole piece is coated with a layer of conductive adhesive, the thickness of the conductive adhesive coating is 0.2-5 um, and the conductive adhesive is selected from polyacrylic acid and conductive carbon. The conductive adhesive coating is arranged to reduce the contact internal resistance.

Preferably, the positive pole piece is provided with a porosity structure in gradient distribution along the thickness direction of the pole piece, and the porosity of the side of the positive pole piece, which faces the negative pole piece, is higher than the porosity of the side of the positive pole piece, which is close to the top cover.

Preferably, the battery comprises two single-sided negative pole pieces, a double-sided positive pole piece and two diaphragms, wherein the single-sided negative pole piece, the diaphragm layer, the double-sided positive pole piece, the diaphragm layer and the other single-sided negative pole piece are stacked in sequence.

The assembling method comprises the following steps: during assembly, a single-sided negative pole piece, a diaphragm layer, a double-sided positive pole piece, the diaphragm layer and another single-sided negative pole piece are sequentially stacked, the double-sided positive pole piece, the diaphragm and the single-sided negative pole piece are bonded together through a hot pressing process, lugs of the double-sided positive pole piece are welded on an externally led positive pole lug, lugs of the single-sided negative pole piece are welded on an externally led negative pole lug in parallel, a pressed battery cell is placed into an aluminum plastic film for packaging, then electrolyte is injected, the battery cell is sealed, drying is sometimes needed, and finally formation, vacuumizing secondary sealing and capacity grading are carried out to obtain a finished battery cell. This structure can double the battery capacity. The battery core can also be assembled by using a section of continuous diaphragm, a single-sided pole piece, a turnover diaphragm, a double-sided pole piece, a turnover diaphragm and a single-sided pole piece are sequentially placed on a diaphragm layer, and the battery core is wrapped by using the diaphragm for one or more circles to obtain the stacked battery core.

Preferably, the battery comprises two single-sided positive pole pieces, one double-sided negative pole piece and two diaphragms, wherein the single-sided positive pole piece, the diaphragm layer, the double-sided negative pole piece, the diaphragm layer and the other single-sided positive pole piece are sequentially stacked.

The invention has the beneficial effects that:

1) The invention uses the electrode formula with high active substance content, and the battery energy is high.

2) The weight and volume ratio of inactive materials are reduced, and the energy density of the battery is obviously improved compared with the prior product. On the premise of ensuring the unchanged endurance of the electronic product, the weight and the volume of the battery are greatly reduced; on the premise of ensuring that the volume of the battery is not changed, the endurance time of the product can be greatly improved.

3) Unlike conventional lithium batteries, the button cell of the present invention uses the button cell top cover and the shell as the positive and negative current collectors, respectively. The design is simplified, the manufacturing process is short, the energy density is improved, the using amount of a current collector and a diaphragm is reduced, and the manufacturing complexity and the manufacturing cost of the battery are greatly reduced.

Drawings

Fig. 1 is a schematic view showing the connection of the internal structure of a button cell battery according to examples 1 to 16;

FIG. 2 is a schematic view of the pole piece of example 3 with through holes formed therein in a direction perpendicular to the thickness direction of the pole piece;

FIG. 3 is a schematic view showing through holes provided in the inner portion of a pole piece in the thickness direction of the pole piece in example 4;

FIG. 4 is a schematic view showing through holes provided in the inside of the pole piece in the direction perpendicular to the thickness direction of the pole piece in example 5;

FIG. 5 is a schematic view of the inside of a wafer according to embodiment 10;

FIG. 6 is a schematic view showing the connection of the internal structure of a laminated battery in example 17;

fig. 7 is a schematic view showing the internal structural connection of a laminated battery in example 18;

fig. 8 is a schematic view showing the internal structural connection of the laminated battery in embodiment 19.

In the figure:

1. pole pieces; 11. a positive electrode plate; 12. a negative pole piece; 13. a through hole; 16. a transition layer; 2. a diaphragm; 3. an insulating sleeve; 4. a top cover; 5. a button shell; 6. an electrolyte; 7. a tab; 8. and (3) an aluminum plastic film.

Detailed Description

The following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings, will make the advantages and features of the invention easier to understand by those skilled in the art, and thus will clearly and clearly define the scope of the invention.

Example 1

Uniformly mixing 90wt.% of lithium cobaltate active substance, 3wt.% of conductive carbon, 2wt.% of carbon nanotube CNT and 5wt.% of polytetrafluoroethylene PTFE, coating the mixture on two sides of a current collector, pressing into a positive membrane with the thickness of 2.0 mm and the surface density of 0.8g/cm & lt 2 & gt in a rolling manner, and punching and cutting the membrane into a button cell positive pole piece 11 with the diameter of 9mm by using a die.

The preparation method comprises the steps of uniformly mixing 92wt.% of artificial graphite active material, 2wt.% of conductive carbon, 1wt.% of carbon nano tube CNT and 5wt.% of hydrogenated nitrile butadiene rubber HNBR, coating the mixture on two sides of a current collector, pressing the mixture into a negative electrode membrane with the thickness of 2.2 mm and the surface density of 0.36g/cm & lt 2 & gt in a rolling manner, and punching and cutting the membrane into the button cell negative electrode piece 12 with the diameter of 10mm by using a die.

The negative pole piece 12 is placed in a button shell 5 with the diameter of 12mm, and then a PP/PE diaphragm 2 with the thickness of 13 microns and the diameter of 11mm and a positive pole piece 11 are sequentially stacked. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, and then the PET insulating sleeve 3 is sleeved on the negative pole piece 12 to prevent the positive pole piece 11 from contacting with the edge of the button shell. Then, lithium ion battery electrolyte 6 is injected, the top cover 4 of the button battery is covered on the positive pole piece 11, and the button battery is sealed by a sealing machine. Finally, the button cell with the diameter of 12mm and the thickness of not more than 5.4mm is obtained, and the charge-discharge capacity of the button cell at normal temperature is not less than 65mAh.

Example 2

94wt.% of lithium nickel cobalt manganese oxide active material, 0.1wt.% of flake graphite, 0.01wt.% of carbon fiber and 5.89wt.% of hydrogenated butaneThe nitrile rubber HNBR is uniformly mixed, the mixture is coated on the two sides of a current collector and then is pressed into a product with the thickness of 3 mm and the surface density of 0.8g/cm by a rolling way ² The positive electrode sheet of (2) is die-cut into a button cell positive electrode sheet 11 having a diameter of 8mm by using a die.

Mixing 94wt.% of hard carbon active material, 2wt.% of conductive carbon, 1wt.% of carbon nano tube CNT and 5wt.% of hydrogenated nitrile butadiene rubber HNBR uniformly, coating the mixture on two sides of a current collector, and pressing the current collector into a material with the thickness of 2.8 mm and the surface density of 0.50g/cm by a rolling manner ² The negative electrode sheet of (1) is die cut into button cell negative electrode sheet 12 with a diameter of 10mm by using a die.

And putting the negative pole piece 12 into a button-type battery shell with the diameter of 11mm, and then sequentially stacking the PP/PE diaphragm 2 with the thickness of 20 microns and the diameter of 10mm and the positive pole piece 11. This process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, and then the PET insulating sleeve 3 is sleeved on the negative pole piece 12 to prevent the positive pole piece 11 from contacting with the edge of the button shell. Then, lithium ion battery electrolyte 6 is injected, the top cover 4 of the button battery is covered on the positive pole piece 11, and the button battery is sealed by a sealing machine. Finally, the button cell with the diameter of 11mm and the thickness of no more than 7.0mm is obtained, and the charge-discharge capacity of the button cell at normal temperature is no less than 65mAh.

Example 3

Referring to fig. 2, 90wt.% of lithium cobaltate active material, 3wt.% of conductive carbon, 2wt.% of carbon nanotube CNT, and 5wt.% of PTFE were uniformly mixed, the mixture was coated on both sides of a current collector, and then pressed by a rolling method to have a thickness of 2.0 mm and an areal density of 0.8g/cm ² The positive electrode sheet of (2) is die-cut into a button cell positive electrode sheet 11 with a diameter of 9mm by using a die. Then, a through hole 13 with the diameter of 0.05mm is punched along the surface of the vertical pole piece by using laser, and the distance between the through hole 13 and the adjacent through hole 13 is 0.2-1.5 mm, thereby obtaining the positive pole piece 11 with the hole.

Mixing 92% of artificial graphite active material with 2wt.% of conductive carbon, 1wt.% of carbon nanotube CNT and 5wt.% of HNBR uniformly, and coating the mixtureCovering the two sides of the current collector, and rolling to obtain a sheet with a thickness of 2.2 mm and an areal density of 0.36g/cm ² The negative electrode sheet of (2) is die cut into a button cell negative electrode sheet 12 having a diameter of 10mm using a die. Then, a through hole 13 with a diameter of 0.05mm was punched along the surface of the vertical pole piece by using a laser, and the straight distance between the through hole 13 and the through hole 13 was 0.2mm, thereby obtaining a negative pole piece 12 with a hole.

The negative pole piece 12 with the hole is placed in a button-type battery case with the diameter of 12mm, and then the PP/PE diaphragm 2 with the thickness of 13 microns and the diameter of 11mm and the positive pole piece 11 with the hole are sequentially stacked. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, and then the PET insulating sleeve 3 is sleeved on the negative pole piece 12 to prevent the positive pole piece 11 from contacting with the edge of the button shell. And then injecting lithium ion battery electrolyte 6, covering the button battery top cover 4 on the positive pole piece 11, and sealing the button battery by a sealing machine. Finally, the button cell with the diameter of 12mm and the thickness of no more than 5.4mm is obtained, and the charge-discharge capacity of the cell at normal temperature is no less than 65mAh.

Example 4

Referring to fig. 3, 98wt.% of lithium cobaltate active material was uniformly mixed with 0.5wt.% of conductive carbon, 0.4wt.% of carbon nanotube CNT, and 1.1wt.% of PTFE, the mixture was coated on both sides of a current collector, and then pressed by a roll press method to have a thickness of 2.0 mm and an areal density of 0.8g/cm ² The positive electrode sheet of (2) is die-cut into a button cell positive electrode sheet 11 with a diameter of 9mm by using a die. Then, a through hole 13 having a diameter of 0.05mm was punched out in the thickness direction of the positive electrode sheet by using a laser, and the distance between the through hole 13 and the through hole 13 was 0.2mm, thereby obtaining a positive electrode sheet 11 having a hole.

Uniformly mixing 95% of artificial graphite active material with 0.8wt.% of conductive carbon, 1.3wt.% of carbon nanotube CNT and 2.9wt.% of HNBR, coating the mixture on two sides of a current collector, and pressing the current collector into a sheet with the thickness of 2.6 mm and the surface density of 0.38g/cm by a rolling manner ² The negative electrode sheet of (1) is die cut into button cell negative electrode sheet 12 with a diameter of 10mm by using a die. Then, a laser is used for punching a pole piece with the diameter of 0.01mm along the thickness direction of the pole pieceThrough holes 13, and the straight distance between the through holes 13 and the through holes 13 is 0.05mm, thereby obtaining the negative pole piece 12 with holes.

The negative pole piece 12 with the hole is placed in a button-type battery case with the diameter of 12mm, and then the PP/PE diaphragm 2 with the thickness of 20 microns and the diameter of 11mm and the positive pole piece 11 with the hole are sequentially stacked. This process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, and then the PET insulating sleeve 3 is sleeved on the negative pole piece 12 to prevent the positive pole piece 11 from contacting with the edge of the button shell. Then, not more than 1g of lithium ion battery electrolyte 6 (soaking of the electrolyte 6 can be accelerated by vacuum) is injected, the button battery top cover 4 is covered on the positive pole piece 11, and the button battery is sealed by a sealing machine. Finally, the button cell with the diameter of 12mm and the thickness of no more than 5.4mm is obtained, and the charge-discharge capacity of the cell at normal temperature is no less than 65mAh.

Example 5

This embodiment differs from

embodiments

3 and 4 in that, as described with reference to fig. 4: in this embodiment, two through holes 13 are provided in the pole piece, the through hole 13 in the first direction being the same as the through hole 13 described in embodiment 3, and the through hole 13 in the second direction being the same as the through hole 14 described in embodiment 4.

Example 6

Uniformly mixing 90wt.% of lithium iron phosphate active material, 3wt.% of graphene, 2wt.% of carbon nanotube CNT and 5wt.% of polyvinylidene fluoride PVDF, coating the mixture on two sides of a current collector, and pressing the current collector into a sheet with a thickness of 3.4 mm and an areal density of 1.36g/cm by a rolling mode ² The positive electrode sheet of (2) is die-cut into a button cell positive electrode sheet 11 with a diameter of 9mm by using a die.

Uniformly mixing 80wt.% of pure silicon negative electrode material, 10wt.% of conductive carbon, 5wt.% of carbon nano tube CNT and 5wt.% of polyvinylidene fluoride PVDF, coating the mixture on two sides of a current collector, and pressing the current collector into a sheet with the thickness of 0.6 mm and the surface density of 0.1g/cm by a rolling mode ² The negative electrode sheet of (2) is die cut into a button cell negative electrode sheet 12 having a diameter of 10mm using a die.

The negative pole piece 12 is put into a button-type battery case with the diameter of 12mm, and then the diaphragm 2 with the thickness of 20 microns and the diameter of 11mm, the metal lithium sheet with the thickness of 0.6 mm and the diameter of 9mm or the metal lithium sheet with holes and the positive pole piece 11 are sequentially stacked. This process needs to guarantee that diaphragm 2 covers negative pole piece 12 completely, and negative pole piece 12 covers positive pole piece 11 completely, and metal lithium piece or foraminiferous metal lithium piece just pastes on positive pole piece 11 surface, sheathes PET insulating cover 3 on next, prevents positive pole piece 11 and button casing edge contact. Or the negative pole piece 12 is put into a button-type battery case with the diameter of 12mm, a metal lithium sheet with the thickness of 0.6 mm and the diameter of 10mm or a metal lithium sheet with holes is pasted on the surface of the negative pole piece, and then the diaphragm 2 and the positive pole piece 11 with the thickness of 20 microns and the diameter of 11mm are sequentially stacked. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, the metal lithium piece or the metal lithium piece with holes is just pasted on the surface of the negative pole piece 11, and then the PET insulating sleeve 3 is sleeved on the negative pole piece or the metal lithium piece with holes to prevent the positive pole piece 11 from contacting with the edge of the button shell. Then, not more than 1g of lithium ion battery electrolyte 6 (soaking of the electrolyte 6 can be accelerated by vacuum) is injected, the button battery top cover 4 is covered on the positive pole piece 11, and the button battery is sealed by a sealing machine. Finally, the button cell with the diameter of 12mm and the thickness of no more than 7.0mm is obtained, and the charge-discharge capacity of the cell at normal temperature is not less than 110mAh.

Example 7:

uniformly mixing 90wt.% of lithium iron manganese phosphate active material, 3wt.% of graphene, 2wt.% of carbon nanotube CNT and 5wt.% of polyvinylidene fluoride PVDF, coating the mixture on two sides of a current collector, and pressing the current collector into a material with the thickness of 4.1 mm and the surface density of 1.36g/cm by a rolling mode ² The positive electrode sheet of (2) is die-cut into a button cell positive electrode sheet 11 with a diameter of 9mm by using a die.

Uniformly mixing 80wt.% of pure silicon negative electrode material, 10wt.% of conductive carbon, 5wt.% of carbon nano tube CNT and 5wt.% of polyvinylidene fluoride PVDF, coating the mixture on two sides of a current collector, and pressing the current collector into a sheet with the thickness of 1.0mm and the surface density of 0.1g/cm by a rolling mode ² The negative electrode sheet of (1), the sheet is die-cut into a sheet having a diameter of 10mm by using a dieButton cell negative pole piece 12.

The negative pole piece 12 is put into a button-type battery case with the diameter of 12mm, and then a diaphragm 2 with the thickness of 50 microns and the diameter of 11mm, a metal lithium sheet with the thickness of 0.9 mm and the diameter of 9mm or a metal lithium sheet with holes and a positive pole piece 11 are sequentially stacked. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, the metal lithium piece or the metal lithium piece with holes is just pasted on the surface of the positive pole piece 11, and then the PET insulating sleeve 3 is sleeved on the positive pole piece 11 to prevent the positive pole piece 11 from contacting with the edge of the button shell. Or the negative pole piece 12 is put into a button-type battery case with the diameter of 12mm, a metal lithium sheet with the thickness of 0.9 mm and the diameter of 10mm or a metal lithium sheet with holes is pasted on the surface of the negative pole piece, and then the diaphragm 2 and the positive pole piece 11 with the thickness of 50 microns and the diameter of 11mm are sequentially stacked. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, the metal lithium piece or the metal lithium piece with holes is just pasted on the surface of the negative pole piece 11, and then the PET insulating sleeve 3 is sleeved on the negative pole piece or the metal lithium piece with holes to prevent the positive pole piece 11 from contacting with the edge of the button shell. Then, not more than 1g of lithium ion battery electrolyte 6 (soaking of the electrolyte 6 can be accelerated by vacuum) is injected, the button battery top cover 4 is covered on the positive pole piece 11, and the button battery is sealed by a sealing machine. Finally, the button cell with the diameter of 12mm and the thickness of no more than 7.0mm is obtained, and the charge-discharge capacity of the cell at normal temperature is not less than 110mAh.

Example 8

Uniformly mixing 90wt.% of lithium cobaltate active substance, 3wt.% of conductive carbon, 2wt.% of carbon nano tube CNT and 5wt.% of lithium manganate, coating the mixture on two sides of a current collector, and pressing the mixture into a sheet with the thickness of 2.0-2.4 mm and the surface density of 0.8g/cm in a rolling manner ² The positive electrode sheet of (2) is die-cut into a button cell positive electrode sheet 11 having a diameter of 9mm using a die.

Uniformly mixing 80wt.% of silicon negative electrode material, 10wt.% of conductive carbon, 5wt.% of carbon nano tube CNT and 5wt.% of hydrogenated nitrile butadiene rubber HNBR, coating the mixture on two sides of a current collector, and pressing the current collector into a thickness of 0.35 mm by a rolling mannerAreal density of 0.06g/cm ² The negative electrode sheet of (2) is die cut into a button cell negative electrode sheet 12 having a diameter of 10mm using a die.

The negative pole piece 12 is put into a button-type battery case with the diameter of 12mm, and then the diaphragm 2 with the thickness of 20 microns and the diameter of 11mm, the metal lithium sheet with the thickness of 0.4 mm and the diameter of 9mm or the metal lithium sheet with holes and the positive pole piece 11 are sequentially stacked. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, the metal lithium piece or the metal lithium piece with holes is just pasted on the surface of the positive pole piece 11, and then the PET insulating sleeve 3 is sleeved on the positive pole piece 11 to prevent the positive pole piece 11 from contacting with the edge of the button shell. Or the negative pole piece 12 is put into a button-type battery case with the diameter of 12mm, a metal lithium sheet with the thickness of 0.4 mm and the diameter of 10mm or a metal lithium sheet with holes is pasted on the surface of the negative pole piece, and then the diaphragm 2 and the positive pole piece 11 with the thickness of 20 microns and the diameter of 11mm are sequentially stacked. This process needs to guarantee that diaphragm 2 covers negative pole piece 12 completely, and negative pole piece 12 covers positive pole piece 11 completely, and metal lithium piece or foraminiferous metal lithium piece just pastes on negative pole piece 11 surface, sheathes PET insulating cover 3 on next, prevents positive pole piece 11 and button casing edge contact. Then, lithium ion battery electrolyte 6 is injected, the top cover 4 of the button battery is covered on the positive pole piece 11, and the button battery is sealed by a sealing machine. Finally, the button cell with the diameter of 12mm and the thickness of not more than 3.5mm is obtained, and the charge-discharge capacity of the cell at normal temperature is not less than 65mAh.

Example 9

Uniformly mixing 90wt.% of lithium cobaltate active substance, 3wt.% of conductive carbon, 2wt.% of carbon nano tube CNT and 5wt.% of lithium manganate, coating the mixture on two sides of a current collector, and pressing the mixture into a sheet with the thickness of 2.4 mm and the surface density of 0.8g/cm by a rolling mode ² The positive electrode sheet of (2) is die-cut into a button cell positive electrode sheet 11 with a diameter of 9mm by using a die.

Uniformly mixing 80wt.% of silicon negative electrode material with 10wt.% of conductive carbon, 5wt.% of carbon nanotube CNT and 5wt.% of hydrogenated nitrile butadiene rubber HNBR, coating the mixture on two sides of a current collector, and then passing through rollersThe thickness of the product is 0.6 mm, the surface density is 0.06g/cm ² The negative electrode sheet of (1) is die cut into button cell negative electrode sheet 12 with a diameter of 10mm by using a die.

The negative pole piece 12 is put into a button-type battery case with the diameter of 12mm, and then the diaphragm 2 with the thickness of 20 microns and the diameter of 11mm, the metal lithium sheet with the thickness of 0.6 mm and the diameter of 9mm or the metal lithium sheet with holes and the positive pole piece 11 are sequentially stacked. This process needs to guarantee that diaphragm 2 covers negative pole piece 12 completely, and negative pole piece 12 covers positive pole piece 11 completely, and metal lithium piece or foraminiferous metal lithium piece just pastes on positive pole piece 11 surface, sheathes PET insulating cover 3 on next, prevents positive pole piece 11 and button casing edge contact. Or the negative pole piece 12 is put into a button-type battery case with the diameter of 12mm, a metal lithium sheet with the thickness of 0.6 mm and the diameter of 10mm or a metal lithium sheet with holes is pasted on the surface of the negative pole piece, and then the diaphragm 2 and the positive pole piece 11 with the thickness of 20 microns and the diameter of 11mm are sequentially stacked. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, the metal lithium piece or the metal lithium piece with holes is just pasted on the surface of the negative pole piece 11, and then the PET insulating sleeve 3 is sleeved on the negative pole piece or the metal lithium piece with holes to prevent the positive pole piece 11 from contacting with the edge of the button shell. Then, lithium ion battery electrolyte 6 is injected, the top cover 4 of the button battery is covered on the positive pole piece 11, and the button battery is sealed by a sealing machine. Finally, the button cell with the diameter of 12mm and the thickness of not more than 3.5mm is obtained, and the charge-discharge capacity of the cell at normal temperature is not less than 65mAh.

Example 10

Referring to fig. 5, 90wt.% of lithium cobaltate active material was uniformly mixed with 3wt.% of conductive carbon, 2wt.% of carbon nanotube CNT, and 5wt.% of PTFE, the mixture was coated on both sides of a current collector, and then pressed by a roll press to a thickness of 0.5mm and an areal density of 0.2g/cm ² The positive electrode sheet 11 of (4) was die-cut into positive electrode pieces 9mm in diameter by using a die. Four positive electrode sheets were stacked in alignment, each two sheets being provided with a transition layer 16, the transition layer 16 being 0.005 mm thick aluminum foil with holes, which was pressed using a pressure of 4psi to form the final positive electrode membrane. Wherein psi is pressureForce units, in pounds force per square inch, 1bar ≈ 14.5psi.

Uniformly mixing 92wt.% of artificial graphite active material, 2wt.% of conductive carbon, 1wt.% of carbon nanotube CNT and 5wt.% of HNBR, coating the mixture on two sides of a current collector, and pressing the current collector into a sheet with a thickness of 0.5mm and an areal density of 0.09g/cm by a rolling manner ² The negative electrode sheet of (4) was die-cut into negative electrode pieces having a diameter of 10mm using a die. Four negative electrode sheets were aligned and stacked with 0.005 mm copper foil with holes sandwiched between every two sheets and pressed into the final negative electrode film using 4psi pressure.

And putting the negative diaphragm into a button-type battery case with the diameter of 12mm, and then sequentially stacking a PP/PE diaphragm 2 with the thickness of 25 microns and the diameter of 11mm and a positive diaphragm. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, and then the PET insulating sleeve 3 is sleeved on the negative pole piece 12 to prevent the positive pole piece 11 from contacting with the edge of the button shell. And then injecting lithium ion battery electrolyte 6, covering the button battery top cover 4 on the positive pole piece 11, and sealing the button battery by a sealing machine. Finally, the button cell with the diameter of 12mm and the thickness of not more than 5.4mm is obtained, and the charge-discharge capacity of the cell at normal temperature is not less than 65mAh.

Example 11

Uniformly mixing 90wt.% of lithium cobaltate active substance, 3wt.% of conductive carbon, 2wt.% of carbon nanotube CNT and 5wt.% of PTFE, coating the mixture on two sides of a current collector, and pressing the current collector into a sheet with the thickness of 0.6 mm and the surface density of 0.2g/cm by a rolling mode ² The positive electrode sheet 11 of (4) was die-cut into positive electrode pieces 9mm in diameter by using a die. Four positive electrode pieces were stacked in alignment with a 0.016 mm aluminum foil with holes sandwiched between each two pieces and pressed into the final positive electrode piece 11 using 50psi pressure.

Uniformly mixing 92wt.% of artificial graphite active material, 2wt.% of conductive carbon, 1wt.% of carbon nanotube CNT and 5wt.% of HNBR, coating the mixture on two sides of a current collector, and pressing the current collector into a sheet with a thickness of 0.6 mm and an areal density of 0.09g/cm by a rolling manner ² Negative electrode film of (2), useThe die punches the membrane into a negative electrode single piece with the diameter of 10 mm. Four negative electrode pieces were aligned and stacked, with 0.01mm copper foil with holes sandwiched between each two pieces, and pressed into the final negative electrode piece 12 using 50psi pressure.

And putting the negative pole piece 12 into a button-type battery case with the diameter of 12mm, and then sequentially stacking the PP/PE diaphragm 2 with the thickness of 20 microns and the diameter of 11mm and the positive pole piece 11. This process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, and then the PET insulating sleeve 3 is sleeved on the negative pole piece 12 to prevent the positive pole piece 11 from contacting with the edge of the button shell. And then injecting lithium ion battery electrolyte 6, covering the button battery top cover 4 on the positive pole piece 11, and sealing the button battery by a sealing machine. Finally, the button cell with the diameter of 12mm and the thickness of no more than 5.4mm is obtained, and the charge-discharge capacity of the cell at normal temperature is no less than 65mAh.

Example 12:

uniformly mixing 90wt.% of lithium cobaltate active substance, 3wt.% of conductive carbon, 2wt.% of carbon nanotube CNT and 5wt.% of HNBR, coating the mixture on two sides of a current collector, and pressing the current collector into a sheet with a thickness of 0.6 mm and an areal density of 0.2g/cm by a rolling manner ² The positive electrode sheet 11 of (2) was die-cut into positive electrode pieces having a diameter of 9mm using a die. Four positive electrode sheets were stacked in alignment with a 0.016 mm aluminum foil with holes sandwiched between each two sheets, and pressed into the final positive electrode sheet 11 using 40psi pressure.

Uniformly mixing 85wt.% of silicon negative electrode material, 5wt.% of conductive carbon, 8wt.% of carbon nanotube CNT and 2wt.% of HNBR, coating the mixture on two sides of a current collector, and pressing the current collector into a sheet with a thickness of 0.15 mm and an areal density of 0.025g/cm by a rolling mode ² The negative electrode sheet 12 of (2) was die-cut into negative electrode pieces having a diameter of 10mm using a die. Four negative electrode pieces were stacked in alignment with a 0.01mm copper foil with holes sandwiched between each two pieces and pressed into the final negative electrode piece 12 using 40psi pressure.

The negative pole piece 12 is put into a button battery case with the diameter of 12mm, and then the PP/PE diaphragm 2 with the thickness of 13 microns and the diameter of 11mm, the metal lithium piece with the thickness of 0.9 mm and the diameter of 9mm or the metal lithium piece with holes and the positive pole piece 11 are sequentially stacked. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, the metal lithium piece or the metal lithium piece with holes is just pasted on the surface of the positive pole piece 11, and then the PET insulating sleeve 3 is sleeved on the positive pole piece 11 to prevent the positive pole piece 11 from contacting with the edge of the button shell. Or the negative pole piece 12 is put into a button-type battery case with the diameter of 12mm, a metal lithium sheet with the thickness of 0.9 mm and the diameter of 10mm or a metal lithium sheet with holes is pasted on the surface of the negative pole piece, and then the PP/PE diaphragm 2 and the positive pole piece 11 with the thickness of 13 microns and the diameter of 11mm are sequentially stacked. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, the metal lithium piece or the metal lithium piece with holes is just pasted on the surface of the negative pole piece 11, and then the PET insulating sleeve 3 is sleeved on the negative pole piece or the metal lithium piece with holes to prevent the positive pole piece 11 from contacting with the edge of the button shell. Then, not more than 1g of lithium ion battery electrolyte 6 (the impregnation of the electrolyte 6 can be accelerated by vacuum) is injected, the button battery top cover 4 is covered on the positive pole piece 11, and the button battery is sealed by a sealing machine. Finally, the button cell with the diameter of 12mm and the thickness of no more than 7.0mm is obtained, and the charge-discharge capacity of the cell at normal temperature is not less than 110mAh.

Example 13:

uniformly mixing 90wt.% of lithium cobaltate active substance, 3wt.% of conductive carbon, 2wt.% of carbon nanotube CNT and 5wt.% of HNBR, coating the mixture on two sides of a current collector, and pressing the current collector into a sheet with a thickness of 0.6 mm and an areal density of 0.2g/cm by a rolling manner ² The positive electrode sheet 11 of (2) was die-cut into positive electrode pieces having a diameter of 9mm using a die. Four positive electrode sheets were stacked in alignment, with a 0.016 mm aluminum foil with holes sandwiched between each two sheets, and pressed into the final positive electrode sheet 11 using a 4-press.

Uniformly mixing 85wt.% of silicon negative electrode material, 5wt.% of conductive carbon, 8wt.% of carbon nanotube CNT and 2wt.% of HNBR, coating the mixture on two sides of a current collector, and pressing the current collector into a sheet with a thickness of 0.25 mm and an areal density of 0.025g/cm by a rolling manner ² The negative electrode sheet 12 of (2), a diaphragm using a dieAnd punching into single negative electrode pieces with the diameter of 10 mm. Four negative electrode pieces were stacked in alignment, with 0.005 mm copper foil with holes sandwiched between each two pieces, and pressed into the final negative electrode piece 12 using a 4psi pressure.

The negative pole piece 12 is put into a button battery case with the diameter of 12mm, and then a PP/PE diaphragm 2 with the thickness of 16 microns and the diameter of 11mm, a metal lithium sheet with the thickness of 0.6 mm and the diameter of 9mm or a metal lithium sheet with holes and the positive pole piece 11 are sequentially stacked. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, the metal lithium piece or the metal lithium piece with holes is just pasted on the surface of the positive pole piece 11, and then the PET insulating sleeve 3 is sleeved on the positive pole piece 11 to prevent the positive pole piece 11 from contacting with the edge of the button shell. Or the negative pole piece 12 is put into a button-type battery case with the diameter of 12mm, a metal lithium sheet with the thickness of 0.6 mm and the diameter of 10mm or a metal lithium sheet with holes is pasted on the surface of the negative pole piece, and then the PP/PE diaphragm 2 with the thickness of 16 microns and the diameter of 11mm and the positive pole piece 11 are sequentially stacked. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, the metal lithium piece or the metal lithium piece with holes is just pasted on the surface of the negative pole piece 11, and then the PET insulating sleeve 3 is sleeved on the negative pole piece or the metal lithium piece with holes to prevent the positive pole piece 11 from contacting with the edge of the button shell. Then, not more than 1g of lithium ion battery electrolyte 6 (soaking of the electrolyte 6 can be accelerated by vacuum) is injected, the button battery top cover 4 is covered on the positive pole piece 11, and the button battery is sealed by a sealing machine. Finally, the button cell with the diameter of 12mm and the thickness of no more than 7.0mm is obtained, and the charge-discharge capacity of the cell at normal temperature is not less than 110mAh.

Example 14

Uniformly mixing 92wt.% of lithium manganate active substance, 1wt.% of conductive carbon, 3wt.% of carbon nanotube CNT and 4wt.% of polyacrylic acid PAA, coating the mixture on two sides of a current collector, and pressing the current collector into a product with the thickness of 0.4 mm and the surface density of 0.2g/cm by a rolling mode ² The positive electrode sheet 11 of (4) was die-cut into positive electrode pieces 9mm in diameter by using a die. Two positive electrode sheets were stacked in alignment with a 0.01mm aluminum foil with holes sandwiched therebetween and pressed using a pressure of 10psiTo form the final positive electrode plate 11.

Mixing 85wt.% of silicon negative electrode material, 5wt.% of conductive carbon, 4wt.% of carbon nanotube CNT and 6wt.% of polyacrylic acid PAA uniformly, coating the mixture on two sides of a current collector, and pressing the current collector into a sheet with the thickness of 0.25 mm and the surface density of 0.025g/cm by a rolling manner ² The negative electrode sheet 12 of (2) was die-cut into negative electrode pieces having a diameter of 10mm using a die. Two negative electrode pieces were aligned and stacked with a 0.005 mm copper foil with holes sandwiched in between, and pressed into the final negative electrode sheet 12 using a pressure of 10 psi.

And placing the negative membrane into a button battery case with the diameter of 12mm, and then sequentially stacking a PP/PE diaphragm 2 with the thickness of 13 microns and the diameter of 11mm, a metal lithium sheet with the thickness of 0.4 mm and the diameter of 9mm or a metal lithium sheet with holes and a positive membrane 11. This process needs to guarantee that diaphragm 2 covers negative pole piece 12 completely, and negative pole piece 12 covers positive pole piece 11 completely, and metal lithium piece or foraminiferous metal lithium piece just pastes on positive pole piece 11 surface, sheathes PET insulating cover 3 on next, prevents positive pole piece 11 and button casing edge contact. Or the negative pole piece 12 is put into a button-type battery case with the diameter of 12mm, a metal lithium sheet with the thickness of 0.4 mm and the diameter of 10mm or a metal lithium sheet with holes is pasted on the surface of the negative pole piece, and then the PP/PE diaphragm 2 and the positive pole piece 11 with the thickness of 13 microns and the diameter of 11mm are sequentially stacked. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, the metal lithium piece or the metal lithium piece with holes is just pasted on the surface of the negative pole piece 11, and then the PET insulating sleeve 3 is sleeved on the negative pole piece or the metal lithium piece with holes to prevent the positive pole piece 11 from contacting with the edge of the button shell. Then, not more than 1g of lithium ion battery electrolyte 6 (soaking of the electrolyte 6 can be accelerated by vacuum) is injected, the button battery top cover 4 is covered on the positive pole piece 11, and the button battery is sealed by a sealing machine. Finally, the button cell with the diameter of 12mm and the thickness of not more than 3.5mm is obtained, and the charge-discharge capacity of the cell at normal temperature is not less than 60mAh.

Example 15

95wt.% of lithium manganate active material, 0.5wt.% of conductive carbon, 0.5wt.% of carbon nanotube CNT, and 4wt.% of lithium manganate active material% of PTFE is mixed evenly, the mixture is coated on two sides of a current collector and then is pressed into a thickness of 0.6 mm in a rolling way, and the surface density is 0.2g/cm ² The positive electrode sheet 11 of (4) was die-cut into positive electrode pieces 9mm in diameter by using a die. Two positive electrode sheets were stacked in alignment with a 0.016 mm aluminum foil with holes sandwiched in between, and pressed into the final positive electrode sheet 11 using 40psi pressure.

Uniformly mixing 95wt.% of silicon negative electrode material, 0.5wt.% of conductive carbon, 0.5wt.% of carbon nanotube CNT and 4wt.% of HNBR, coating the mixture on two sides of a current collector, and pressing the current collector into a sheet with the thickness of 0.15 mm and the surface density of 0.025g/cm in a rolling manner ² The negative electrode sheet 12 of (4) was die-cut into negative electrode pieces having a diameter of 10mm using a die. Two negative electrode single sheets are aligned and stacked, a layer of copper foil with holes of 0.005 mm is sandwiched between the two negative electrode single sheets, and the two negative electrode single sheets are pressed into a final negative electrode pole piece 12 by using 40 pressure.

The negative pole piece 12 is put into a button battery case with the diameter of 12mm, and then a PP/PE diaphragm 2 with the thickness of 16 microns and the diameter of 11mm, a metal lithium sheet with the thickness of 0.6 mm and the diameter of 9mm or a metal lithium sheet with holes and the positive pole piece 11 are sequentially stacked. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, the metal lithium piece or the metal lithium piece with holes is just pasted on the surface of the positive pole piece 11, and then the PET insulating sleeve 3 is sleeved on the positive pole piece 11 to prevent the positive pole piece 11 from contacting with the edge of the button shell. Or the negative pole piece 12 is put into a button-type battery case with the diameter of 12mm, a metal lithium sheet with the thickness of 0.6 mm and the diameter of 10mm or a metal lithium sheet with holes is pasted on the surface of the negative pole piece, and then the PP/PE diaphragm 2 and the positive pole piece 11 with the thickness of 16 microns and the diameter of 11mm are sequentially stacked. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, the metal lithium piece or the metal lithium piece with holes is just pasted on the surface of the negative pole piece 11, and then the PET insulating sleeve 3 is sleeved on the negative pole piece or the metal lithium piece with holes to prevent the positive pole piece 11 from contacting with the edge of the button shell. Then, not more than 1g of lithium ion battery electrolyte 6 (the impregnation of the electrolyte 6 can be accelerated by vacuum) is injected, the button battery top cover 4 is covered on the positive pole piece 11, and the button battery is sealed by a sealing machine. Finally, the button cell with the diameter of 12mm and the thickness of not more than 3.5mm is obtained, and the charge-discharge capacity of the cell at normal temperature is not less than 60mAh.

Example 16:

uniformly mixing 90wt.% of lithium cobaltate active substance, 2wt.% of conductive carbon, 1wt.% of carbon nano tube CNT, 3wt.% of oxide solid electrolyte LATP and 4wt.% of HNBR, coating the mixture on two sides of a current collector, and pressing the mixture into a current collector with a thickness of 2.0 mm and an area density of 0.8g/cm by a rolling manner ² The positive electrode sheet of (2) is die-cut into a button cell positive electrode sheet 11 with a diameter of 9mm by using a die.

Mixing 92wt.% of artificial graphite active material with 2wt.% of conductive carbon, 1wt.% of carbon nanotube CNT, 1wt.% of oxide solid electrolyte LLZO and 4wt.% of PTFE, coating the mixture on both sides of a current collector, and pressing by a rolling manner to obtain a current collector with a thickness of 2.5 mm and an areal density of 0.36g/cm ² The negative electrode sheet of (1) is die cut into button cell negative electrode sheet 12 with a diameter of 10mm by using a die.

And putting the negative pole piece 12 into a button-type battery shell with the diameter of 12mm, and then sequentially stacking the PP/PE diaphragm 2 with the thickness of 13 microns and the diameter of 11mm and the positive pole piece 11. The process needs to ensure that the diaphragm 2 completely covers the negative pole piece 12, the negative pole piece 12 completely covers the positive pole piece 11, and then the PET insulating sleeve 3 is sleeved on the negative pole piece 12 to prevent the positive pole piece 11 from contacting with the edge of the button shell. Then, not more than 1g of lithium ion battery electrolyte 6 (the impregnation of the electrolyte 6 can be accelerated by vacuum) is injected, the button battery top cover 4 is covered on the positive pole piece 11, and the button battery is sealed by a sealing machine. Finally, the button cell with the diameter of 12mm and the thickness of not more than 6.0mm is obtained, and the charge-discharge capacity of the cell at normal temperature is not less than 65mAh.

Example 17:

referring to fig. 6, 90wt.% of lithium iron phosphate active material, 3wt.% of graphene, 2wt.% of carbon nanotube CNT, and 5wt.% of polyvinylidene fluoride PVDF were uniformly mixed, the mixture was coated on one side of a current collector, and then pressed by a rolling method to have a thickness of 4.1 mmThe areal density of the glass fiber was 1.36g/cm ² The positive electrode sheet of (1) is die-cut into the battery positive electrode sheet 11 using a die.

Uniformly mixing 80wt.% of silicon-containing negative electrode material, 10wt.% of conductive carbon, 5wt.% of carbon nanotube CNT and 5wt.% of polyvinylidene fluoride PVDF, coating the mixture on one side of a current collector, and pressing the current collector into a sheet with the thickness of 1.0mm and the surface density of 0.1g/cm by a rolling mode ² The negative electrode sheet of (1) is die cut into the battery negative electrode tab 12 using a die. The negative pole piece 12 is larger than the positive pole piece 11 in the length and width directions, so that the positive pole piece 11 can be completely covered.

Firstly, respectively welding a positive pole piece 11 and a negative pole piece 12 to lead out a tab 7, attaching a metal lithium piece or a metal lithium piece with holes, the thickness of which is 0.2-1.0 mm and the size of which is the same as that of the positive pole piece 11 or the negative pole piece 12, to the surface of the positive pole piece 11 or the negative pole piece 12, then laminating the negative pole piece 12, a diaphragm 2 and the positive pole piece 11 into a battery cell, then putting the laminated battery cell into an aluminum plastic film 8 for packaging, then injecting an electrolyte 6, sealing, and finally carrying out formation, vacuumizing secondary sealing and capacity division to obtain a finished battery cell.

Example 18:

referring to the attached drawing 7, 90wt.% of lithium iron phosphate active material, 3wt.% of graphene, 2wt.% of carbon nanotube CNT, and 5wt.% of polyvinylidene fluoride PVDF were uniformly mixed, the mixture was coated on both sides of a current collector, and then pressed by a roll press method to have a thickness of 4.1 mm and an areal density of 1.36g/cm ² The positive electrode sheet of (2) is die-cut into the double-sided battery positive electrode sheet 11 by using a die.

Uniformly mixing 80wt.% of silicon-containing negative electrode material, 10wt.% of conductive carbon, 5wt.% of carbon nanotube CNT and 5wt.% of polyvinylidene fluoride PVDF, coating the mixture on one side of a current collector, and pressing the current collector into a sheet with the thickness of 1.0mm and the surface density of 0.1g/cm by a rolling mode ² The negative electrode sheet of (2) is die-cut into the single-sided battery negative electrode sheet 121 by using a die.

Attaching a metal lithium sheet or a perforated metal lithium sheet with the thickness of 0.2-1.0 mm and the same size as the positive pole piece 11 or the negative pole piece 121 on the two side surfaces of the positive pole piece 11 or the negative pole piece 121, sequentially placing a single-sided negative pole piece 121, a diaphragm 2, a double-sided positive pole piece 11, a diaphragm 2 and another single-sided negative pole piece 121 during assembly, bonding the negative pole piece, the diaphragm 2 and the positive pole piece together by using a hot pressing process to obtain a stacked battery cell, respectively welding external lugs on the two layers of single-sided negative pole pieces 121 and the double-sided positive pole piece 11 which are connected in parallel, then placing the battery cell into an aluminum plastic film 8 for packaging, then injecting electrolyte 6, sealing, finally carrying out formation, vacuumizing secondary sealing and capacity grading to obtain a finished battery cell. The battery cell with the structure can double the battery capacity.

Example 19:

referring to fig. 8, 90wt.% of lithium iron phosphate active material, 3wt.% of graphene, 2wt.% of carbon nanotube CNT, and 5wt.% of polyvinylidene fluoride PVDF were uniformly mixed, the mixture was coated on one side of a current collector, and then pressed by a roll pressing method to have a thickness of 3 mm and an areal density of 1.36g/cm ² The positive electrode sheet of (1) is die-cut into a single-sided positive electrode sheet 111 using a die.

Uniformly mixing 80wt.% of silicon-containing negative electrode material, 10wt.% of conductive carbon, 5wt.% of carbon nanotube CNT and 5wt.% of polyvinylidene fluoride PVDF, coating the mixture on two sides of a current collector, and pressing the current collector into a sheet with the thickness of 2.0 mm and the surface density of 0.1g/cm by a rolling mode ² The negative electrode sheet of (2) is die-cut into the double-sided negative electrode sheet 12 by using a die.

Attaching a metal lithium sheet or a perforated metal lithium sheet with the thickness of 0.2-1.0 mm and the same size as the positive pole piece 111 or the negative pole piece 12 to the surface of the positive pole piece 111 or the surface of the two sides of the negative pole piece 12, stacking the single-sided positive pole piece 111, the diaphragm 2, the double-sided negative pole piece 12, the diaphragm 2 and the other single-sided positive pole piece 111 in sequence during assembly, then bonding the double-sided negative pole piece 12, the diaphragm 2 and the single-sided positive pole piece 111 together by using a hot pressing process to obtain a stacked battery cell, respectively welding external lugs to the two layers of the single-sided positive pole piece 111 and the double-sided negative pole piece 12 which are connected in parallel, then putting the stacked battery cell into an aluminum plastic film 8 for packaging, then injecting an electrolyte 6, sealing, and finally performing formation, vacuum pumping secondary sealing and capacity grading to obtain a finished battery cell. The battery core with the structure can double the capacity of the battery.

The above embodiments are provided only for illustrating the technical idea and features of the present invention, and the purpose of the present invention is to provide those skilled in the art with understanding and implementing the present invention, and not to limit the scope of the present invention, and all equivalent changes or modifications made according to the spirit of the present invention should be covered by the scope of the present invention.

Claims

1. The pole piece for the lithium ion battery is characterized by comprising a current collector and a conducting layer coated on the surface of the current collector, wherein the thickness of the pole piece is 20-4000 um, and the conducting layer comprises the following components: 80.0 to 98.5wt.% active material; 0.1 to 10wt.% of a dot-or planar conductive material; 0.01 to 5.0wt.% of a linear conductive agent; 0.2 to 10wt.% binder.

2. The electrode sheet of claim 1, wherein the electrode sheet comprises a positive electrode sheet, and the active material in the conductive layer of the positive electrode sheet is selected from any one or more of lithium cobaltate, lithium nickel cobalt manganese oxide, lithium iron phosphate, lithium manganese oxide, and lithium manganese iron phosphate;

the dot or planar conductive material is selected from any one or a mixture of carbon black, flake graphite and graphene;

3. The electrode plate of claim 1, wherein the electrode plate comprises a negative electrode plate, and the active material in the conductive layer of the negative electrode plate is selected from graphite, hard carbon, soft carbon, silicon, and oxide SiO of silicon _x Lithiated SiO _x -Li _y SiO _x Any one of or a mixture of graphite and silicon, metallic lithium, lithium titanateA plurality of mixtures;

the point-like or planar conductive material is carbon black;

the linear conductive agent is carbon nano tube or carbon fiber;

the binder is selected from any one or more of sodium carboxymethylcellulose (CMC), styrene Butadiene Rubber (SBR), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyacrylic acid (PAA) and Hydrogenated Nitrile Butadiene Rubber (HNBR).

4. The electrode sheet of claim 1, wherein the conductive layer further comprises an oxide solid electrolyte, the content of the oxide solid electrolyte is 0.1-15 wt%, and the oxide solid electrolyte is selected from LATP-Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ 、LLZO-Li _6.4 La ₃ Zr _1.4 Ta _0.6 O ₁₂ Any one of them.

5. The pole piece for the lithium ion battery of claim 1, wherein a plurality of through holes are arranged on the pole piece, the through holes are distributed along the thickness direction of the pole piece and/or the direction vertical to the thickness direction of the pole piece, the diameter of each through hole is 0.01-100 um, and the distance between every two adjacent through holes is 0.02-0.5 mm.

6. The pole piece for the lithium ion battery of claim 1, wherein the pole piece is formed by compounding a plurality of layers of diaphragms, a transition layer is arranged between the diaphragms, the thickness of the diaphragms is 50-500 um, and the thickness of the transition layer is 5-25 um.

7. The electrode plate of claim 1, wherein a metal lithium foil layer or a metal lithium sheet layer is disposed on a side of the electrode plate facing an adjacent electrode plate, the thickness of the metal lithium foil layer or the metal lithium sheet layer is 2-1000 μm, and the metal lithium foil layer or the metal lithium sheet layer has the same shape and the same area as the electrode plate.

8. The electrode sheet of claim 7, wherein the metal lithium foil layer or the lithium sheet layer has pores, the porosity is 1-80%, and the diameter of the pores is 0.05-2 mm.

9. A lithium ion battery is characterized by comprising a positive pole piece, a negative pole piece and a diaphragm, wherein the positive pole piece and/or the negative pole piece is/are the pole piece for the lithium ion battery in any one of claims 1 to 8.

10. The lithium ion battery of claim 9, wherein the number of the positive electrode sheet, the negative electrode sheet and the diaphragm is one.

11. The lithium ion battery of claim 10, wherein the membrane has a thickness of 5-250 um, the positive electrode sheet has a thickness of 40-4000 um, and the negative electrode sheet has a thickness of 20-3000 um.

12. The lithium ion battery of claim 11, further comprising a button housing disposed outside the positive electrode plate and the negative electrode plate, wherein the negative electrode plate, the separator, and the positive electrode plate are sequentially disposed from the bottom of the button housing upward, the positive electrode plate has a diameter of 5-20 mm, the separator has a diameter of 6-22 mm, the negative electrode plate has a diameter of 5.6-21 mm, the button housing has a diameter of 6.1-22.1 mm and a thickness of 0.05-0.2 mm, the lithium ion battery further comprises an insulating sleeve disposed between the button housing and the electrode plate, and a top cap disposed above the positive electrode plate, the top cap has a diameter of 5-21 mm and a thickness of 0.05-0.2 mm.

13. The lithium ion battery of claim 11, wherein a metal sheet is disposed on one side of the positive electrode sheet away from the negative electrode sheet and/or on one side of the negative electrode sheet away from the positive electrode sheet, the metal sheet is made of aluminum foil or copper foil, the thickness of the metal sheet is 5-25 μm, and the diameter of the metal sheet is equal to the diameter of the positive electrode sheet or the negative electrode sheet.

14. The lithium ion battery of claim 13, wherein one or both surfaces of the metal sheet are coated with a layer of conductive adhesive, the thickness of the conductive adhesive coating is 0.2-5 um, and the conductive adhesive is selected from polyacrylic acid and conductive carbon.

15. The lithium ion battery of claim 10, wherein a layer of conductive adhesive is coated on the surface of the positive electrode sheet close to the top cap, the thickness of the conductive adhesive coating is 0.2-5 um, and the conductive adhesive is selected from polyacrylic acid and conductive carbon.

16. The lithium ion battery of claim 10, wherein the positive electrode plate is provided with a porosity structure with gradient distribution along the thickness direction of the plate, and the porosity of the positive electrode plate facing the negative electrode plate is higher than the porosity of the positive electrode plate away from the negative electrode plate.

17. The lithium ion battery of claim 9, comprising two single-sided negative electrode sheets, one double-sided positive electrode sheet and two diaphragms, wherein the single-sided negative electrode sheet, the diaphragm layer, the double-sided positive electrode sheet, the diaphragm layer and the other single-sided negative electrode sheet are sequentially stacked.

18. The lithium ion battery of claim 9, comprising two single-sided positive electrode plates, one double-sided negative electrode plate, and two diaphragms, wherein the single-sided positive electrode plate, the diaphragm layer, the double-sided negative electrode plate, the diaphragm layer, and the other single-sided positive electrode plate are stacked in sequence.