CN219303705U - Pole piece and battery - Google Patents
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- CN219303705U CN219303705U CN202223419676.3U CN202223419676U CN219303705U CN 219303705 U CN219303705 U CN 219303705U CN 202223419676 U CN202223419676 U CN 202223419676U CN 219303705 U CN219303705 U CN 219303705U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract
The utility model relates to the field of batteries, in particular to a pole piece and a battery comprising the pole piece. The pole piece comprises a current collector, an active material coating arranged on one side or two side surfaces of the current collector, a metal oxide layer arranged on the outer surface of the active material coating, and a safety coating arranged on the outer surface of the metal oxide layer, wherein the safety coating completely covers the surface and the side surface of the metal oxide layer. The pole piece can solve the problems of low primary efficiency of the lithium ion battery and potential safety hazards caused by short circuit between the first pole piece and the second pole piece.
Description
Technical Field
The utility model relates to the field of batteries, in particular to a pole piece and a battery comprising the pole piece.
Background
At present, countries in the world face different degrees of energy crisis, fossil fuels are still main energy sources, and the influence of fossil fuels on the environment forces a large number of researchers to find suitable novel green renewable energy sources to replace. Among them, lithium ion batteries are a focus of attention because of their advantages of high energy density, long service life, environmental friendliness, and the like.
However, the lithium ion battery mainly has the following two problems, which affect its application.
First, the first time the efficiency is low. The current commercial lithium ion battery cathode material is mainly graphite, but in order to improve the energy density of the lithium ion battery, the prior art adopts a silicon oxide material with the capacity far higher than that of the graphite as the cathode material, and the silicon oxide material has the defect of low efficiency for the first time.
Second, there is a safety hazard. The lithium ion battery mainly comprises a positive plate, a negative plate, a diaphragm and electrolyte, at present, the manufacturing process of the lithium ion battery firstly needs to process the positive plate and the negative plate, then the diaphragm is assembled between the positive plate and the negative plate through winding or lamination procedures, the process is very complex, the condition of diaphragm folding and wrinkling is easy to occur, the diaphragm strength is lower, the diaphragm is easy to puncture by metal burrs, beads or bulges generated in the processing process, the protection of the diaphragm is easy to be lost between the positive plate and the negative plate, thus direct contact leads to short circuit, self discharge is generated, loss is caused to the density of the battery, and the battery is fast heated, bulges, even fire and explosion are likely to occur, and potential safety hazards exist.
Therefore, a search method is required to improve the first efficiency of the battery and to improve the safety performance of the battery.
Disclosure of Invention
The utility model aims to overcome the technical problems in the prior art and provides a pole piece and a battery comprising the pole piece. The pole piece can solve the problems of low primary efficiency of the lithium ion battery and potential safety hazards caused by short circuit between the first pole piece and the second pole piece; the battery of the utility model can not contain a diaphragm, solves the short circuit between the first pole piece and the second pole piece caused by the diaphragm, reduces the cost and has application prospect.
The first aspect of the utility model provides a pole piece, which comprises a current collector, an active material coating arranged on one side or two side surfaces of the current collector, a metal oxide layer arranged on the outer surface of the active material coating, and a safety coating arranged on the outer surface of the metal oxide layer, wherein the safety coating completely covers the surface and the side surface of the metal oxide layer.
In one example, the security coating completely covers the surface and sides of the metal oxide layer and the sides of the active material coating.
In one example, the safety coating completely covers the surface and sides of the pole piece.
In one example, the thickness of the safety coating is 2% -48% of the total thickness of the pole piece.
In one example, the metal oxide layer has a thickness of 2 μm to 40 μm and the security coating has a thickness of 5 μm to 30 μm.
In one example, the metal oxide layer has a porosity of 20% to 80% and the security coating has a porosity of 20% to 80%.
In one example, the ratio of the porosity of the metal oxide layer to the porosity of the security coating is 1 (0.25-4).
The second aspect of the utility model provides a battery comprising a pole piece according to the first aspect of the utility model.
In one example, the battery includes a first pole piece and a second pole piece, at least one of the first pole piece and the second pole piece being the pole piece, and the first pole piece and the second pole piece being separated by the safety coating.
In one example, the battery is a wound or laminated battery.
Through the technical scheme, compared with the prior art, the utility model has at least the following advantages:
(1) The pole piece comprises the metal oxide layer, wherein the metal oxide layer comprises a lithium compound, so that the first efficiency of the battery can be effectively improved;
(2) The pole piece comprises the safety coating, and the safety coating at least completely covers the surface and the side surface of the metal oxide layer, so that the contact between the first pole piece and the second pole piece can be effectively blocked, the occurrence of short circuit between the first pole piece and the second pole piece is prevented, and the safety performance is effectively improved;
(3) The battery of the utility model can be free of a diaphragm, effectively improves the energy density of the battery and reduces the production cost of the battery.
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
Drawings
Fig. 1 is a schematic cross-sectional view of a pole piece according to an example of the present utility model.
Fig. 2 is a schematic cross-sectional view of a pole piece according to an example of the present utility model.
Figure 3 shows a schematic cross-sectional view of a pole piece according to an example of the utility model.
Fig. 4 is a schematic cross-sectional view of a pole piece according to an example of the present utility model.
Fig. 5 is a schematic cross-sectional view of a pole piece according to an example of the present utility model.
Fig. 6 is a schematic cross-sectional view of a pole piece according to an example of the present utility model.
Fig. 7 is a schematic cross-sectional view of a pole piece according to an example of the present utility model.
Fig. 8 is a schematic cross-sectional view of a pole piece according to an example of the present utility model.
Fig. 9 is a schematic cross-sectional view of a battery according to an example of the present utility model.
Fig. 10 is a schematic cross-sectional view of a battery according to an example of the present utility model.
Fig. 11 is a schematic cross-sectional view of a battery according to an example of the present utility model.
Fig. 12 is a schematic cross-sectional view of a battery according to an example of the present utility model.
Description of the reference numerals
1-a current collector; 2-active material coating; a 3-metal oxide layer; 4-a security coating;
5-1-a first pole piece current collector; 5-2-a first pole piece active material coating; 5-3-a first pole piece metal oxide layer; 5-4-a first pole piece safety coating; 5-a first pole piece;
6-1-second pole piece current collector; 6-2-second pole piece active material coating; 6-3-second-pole piece metal oxide layer; 6-4-second pole piece security coating; 6-a second pole piece;
7-membrane.
Detailed Description
The following describes specific embodiments of the present utility model in detail. It should be understood that the detailed description and specific examples, while indicating and illustrating the utility model, are not intended to limit the utility model.
The pole piece according to the embodiment of the utility model is shown in fig. 1-8, wherein fig. 1-8 are each a schematic cross-sectional view of a pole piece according to an example of the utility model, and the cross-section is a cross-section along the width direction of the pole piece, and in the utility model, the width direction of the pole piece refers to the short side direction of the pole piece. The pole piece is exemplarily described below with reference to the accompanying drawings.
In a first aspect of the present utility model, as shown in fig. 1, in an example of the present utility model, the pole piece includes a current collector 1, active material coatings 2 disposed on both side surfaces of the current collector 1, a metal oxide layer 3 disposed on an outer surface of the active material coatings 2, and a safety coating 4 disposed on an outer surface of the metal oxide layer 3, where the safety coating 4 completely covers a surface and sides of the metal oxide layer 3.
In the present utility model, the side surfaces of the metal oxide layer 3 refer to four side surfaces of the metal oxide layer 3, namely, front, rear, left and right side surfaces.
In the present utility model, the active material coating layer may be provided on one side surface of the current collector or on both side surfaces of the current collector according to various needs.
As shown in fig. 2, in an example of the present utility model, the pole piece includes a current collector 1, an active material coating 2 disposed on one side surface of the current collector 1, a metal oxide layer 3 disposed on an outer surface of the active material coating 2, and a safety coating 4 disposed on an outer surface of the metal oxide layer 3, the safety coating 4 completely covering the surface and sides of the metal oxide layer 3.
In the utility model, the shapes of the metal oxide layer and the safety coating can be adjusted according to the needs, and the safety coating only needs to cover the surface and the side surface of the metal oxide layer completely.
For example, as shown in fig. 3, in an example, the metal oxide layer 3 has a trapezoid shape in cross section, the security coating 4 has a rectangular shape in cross section, and the security coating 4 completely covers the surface and the side surfaces of the metal oxide layer 3.
As another example, as shown in fig. 4, in an example, the metal oxide layer 3 has a trapezoid shape in cross section, the security coating 4 has a trapezoid shape in cross section, and the security coating 4 completely covers the surface and the side surfaces of the metal oxide layer 3.
As another example, as shown in fig. 5, in an example, the cross section of the metal oxide layer 3 is a rectangle, the cross section of the security coating 4 is a trapezoid, and the security coating 4 completely covers the surface and the side surfaces of the metal oxide layer 3.
In the present utility model, when the active material layer is coated on both side surfaces of the current collector, the shapes of the metal oxide layer and the safety coating layer on both sides of the electrode sheet may be correspondingly identical, as shown in fig. 1, 3, 4 and 5; the shapes of the metal oxide layer and the safety coating layer on both sides of the pole piece may also be correspondingly different, as shown in fig. 6, in an example, the cross section of the metal oxide layer 3 on one side of the pole piece is a rectangle, the cross section of the safety coating layer 4 is a rectangle, the cross section of the metal oxide layer 3 on the other side of the pole piece is a trapezoid, and the cross section of the safety coating layer 4 is a trapezoid.
The safety coating may entirely cover the surface and side surfaces of the metal oxide layer and the side surfaces of the active material layer.
As shown in fig. 7, in an example of the present utility model, the pole piece includes a current collector 1, an active material coating 2 disposed on both side surfaces of the current collector 1, a metal oxide layer 3 disposed on an outer surface of the active material coating 2, and a safety coating 4 disposed on an outer surface of the metal oxide layer 3, the safety coating 4 entirely covering the surface and side surfaces of the metal oxide layer 3 and the side surfaces of the active material coating 2.
The safety coating completely covers the surface and the side surfaces of the pole piece.
As shown in fig. 8, in an example of the present utility model, the pole piece includes a current collector 1, active material coatings 2 disposed on both side surfaces of the current collector 1, a metal oxide layer 3 disposed on an outer surface of the active material coatings 2, and a safety coating 4 disposed on an outer surface of the metal oxide layer 3, the safety coating 4 completely covering the surface and the side surfaces of the pole piece.
The thickness of the security coating may be 2% -48%, such as 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47% or 48%, of the total thickness of the pole piece.
In one example, the thickness of the safety coating is 3% -20% of the total thickness of the pole piece.
In one example, the thickness of the safety coating is 5% -10% of the total thickness of the pole piece.
The metal oxide layer may have a thickness of 2 μm-40 μm, for example 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm or 40 μm.
In one example, the metal oxide layer has a thickness of 4 μm to 20 μm.
The thickness of the security coating may be 5 μm to 30 μm, for example 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm or 30 μm.
In one example, the security coating has a thickness of 8 μm to 20 μm.
In the present utility model, the thickness of the metal oxide layer refers to a single layer thickness of the metal oxide layer, and the thickness of the safety coating layer refers to a single layer thickness of the safety coating layer.
The metal oxide layer may have a porosity of 20% -80%, such as 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%.
In one example, the metal oxide layer has a porosity of 30% -60%.
The security coating may have a porosity of 20% -80%, for example 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%.
In one example, the security coating has a porosity of 30% -60%.
The inventor of the present utility model found that a specific ratio exists between the porosity of the metal oxide layer and the porosity of the safety coating, so that the battery prepared from the pole piece has higher energy density and larger rate capability.
The ratio of the porosity of the metal oxide layer to the porosity of the security coating may be 1 (0.25-4), such as 1:0.25, 1:0.5, 1:0.75, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, or 1:4.
In one example, the ratio of the porosity of the metal oxide layer to the porosity of the security coating is 1 (1-2).
In the present utility model, the terms "active material coating", "metal oxide layer" and "safety coating" have the meaning conventional in the art. The specific components and proportions of the active material coating, the metal oxide layer and the safety coating can be selected according to a formula conventional in the art, and the technical effect of the utility model can be achieved.
For example, the active material layer includes an active material, a first conductive agent, and a first binder. The active material is, for example, lithium cobaltate, lithium manganate, lithium iron phosphate, lithium nickel cobalt manganate (811), lithium nickel cobalt manganate (622), lithium nickel cobalt manganate (523), lithium nickel cobalt manganate (111), lithium nickel cobalt aluminate, lithium-rich manganese-based material, lithium iron manganese phosphate or lithium titanate; or the active material is, for example, natural graphite, artificial graphite, hard carbon, carbon nanotubes, graphitized mesophase carbon microspheres, amorphous carbon, graphene or a silicon material (e.g., siO 2 )。
The content of the active substance is 90-99.6 wt%, the content of the first conductive agent is 0.1-10 wt% and the content of the first binder is 0.1-10 wt% based on the total weight of the active material coating.
For another example, the metal oxide layer includes a lithium compound, a second conductive agent, and a second binder. The lithium compound is, for example, li 2 NiO 2 (LNO)、Li 5 FeO 4 (LFO)、Li 2 O、LiPF 6 、LiC(SO 2 CF 3 ) 3 、LiSiF 6 、LiBOB、LiTFSI、LiBF 4 、LiAsF 6 、LiClO 4 、LiB(C 6 H 5 ) 4 、LiCH 3 SO 3 、LiCF 3 SO 3 、LiN(SO 2 CF 3 ) 2 Or lithium difluoroborate.
The lithium compound may be present in an amount of 80 to 99.6 wt% (e.g., 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 99.6 wt%) and the second conductive agent may be present in an amount of 0.2 to 10 wt% (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, or 0.2 wt%) and the second binder may be present in an amount of 0.2 to 10 wt% (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, or 0.2 wt%).
In one example, the lithium compound is present in an amount of 94 to 99 wt%, the second conductive agent is present in an amount of 0.5 to 3 wt%, and the second binder is present in an amount of 0.5 to 3 wt%, based on the total weight of the metal oxide layer.
In one example, the content of lithium element in the metal oxide layer is 1g/m 2 -5g/m 2 For example 1g/m 2 、2g/m 2 、3g/m 2 、4g/m 2 Or 5g/m 2 。
As another example, the security coating includes, for example, an ion-conductive ceramic, nanofibers, and a third binder.
The ion-conducting ceramic is, for example, lithium aluminate, lithium nitride, silicon dioxide, garnet-type electrolyte Li 6.4 La 3 Zr 2 Al 0.2 O 12 Or perovskite type electrolyte Li 3x La 2/3-x TiO 3 The method comprises the steps of carrying out a first treatment on the surface of the The nanofibers are, for example, bacterial nanofibers or plant nanofibers.
The content of the ion conductive ceramic is 75-94.5 wt%, the content of the nanofiber is 5-25 wt% and the content of the third binder is 0.5-2 wt% based on the total weight of the safety coating.
The first conductive agent and the second conductive agent are each independently, for example, a conductive carbon material, conductive carbon black SP, ketjen black, carbon tube, or graphene. The first binder, the second binder, and the third binder are, for example, each independently polyvinylidene fluoride, sodium hydroxycellulose, lithium hydroxycellulose, polyacrylic acid, tetrafluoroethylene-hexafluoropropylene monopolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polyacrylic alcohol, sodium polyacrylate, potassium polyacrylate, lithium polyacrylate, polyimide, polyamideimide, styrene Butadiene Rubber (SBR), polyvinyl alcohol (PVA), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), aqueous acrylic resin, carboxymethyl cellulose (CMC), or sodium carboxymethyl cellulose (CMC-Na).
In a second aspect of the utility model there is provided a battery comprising a pole piece according to the first aspect of the utility model.
A schematic view of a battery according to an embodiment of the present utility model is shown in fig. 9 to 12, where fig. 9 to 12 are schematic cross-sectional views of a battery according to an example of the present utility model, and the cross-section is a cross-section along the width direction of the battery, and in the present utility model, the width direction of the battery refers to the long side direction of a pole piece included in the battery. The battery is exemplarily described below with reference to the accompanying drawings.
In the utility model, the battery comprises a first pole piece and a second pole piece, and at least one of the first pole piece and the second pole piece is the pole piece.
For example, the first pole piece of the battery is the pole piece according to the first aspect of the utility model, and the second pole piece of the battery is the pole piece according to the first aspect of the utility model.
As shown in fig. 9, in one example, the battery includes a first pole piece 5, a second pole piece 6, and a separator 7; the first pole piece 5 is the pole piece according to the first aspect of the present utility model, the first pole piece 5 comprises a first pole piece current collector 5-1, first pole piece active material coatings 5-2 arranged on two side surfaces of the first pole piece current collector 5-1, a first pole piece metal oxide layer 5-3 arranged on the outer surface of the first pole piece active material coatings 5-2, and a first pole piece safety coating 5-4 arranged on the outer surface of the first pole piece metal oxide layer 5-3, and the first pole piece safety coating 5-4 completely covers the surface and the side surface of the first pole piece metal oxide layer 5-3; the second pole piece 6 is the pole piece according to the first aspect of the present utility model, the second pole piece 6 includes a second pole piece current collector 6-1, second pole piece active material coatings 6-2 disposed on two side surfaces of the second pole piece current collector 6-1, a second pole piece metal oxide layer 6-3 disposed on an outer surface of the second pole piece active material coatings 6-2, and a second pole piece safety coating 6-4 disposed on an outer surface of the second pole piece metal oxide layer 6-3, and the second pole piece safety coating 6-4 completely covers the surface and side surfaces of the second pole piece metal oxide layer 6-3; the diaphragm 7 is arranged between the first pole piece 5 and the second pole piece 6.
The first pole piece and the second pole piece may be separated by the safety coating instead of a diaphragm.
As shown in fig. 10, in one example, the battery includes a first pole piece 5 and a second pole piece 6; the first pole piece 5 is the pole piece according to the first aspect of the present utility model, the first pole piece 5 comprises a first pole piece current collector 5-1, first pole piece active material coatings 5-2 arranged on two side surfaces of the first pole piece current collector 5-1, a first pole piece metal oxide layer 5-3 arranged on the outer surface of the first pole piece active material coatings 5-2, and a first pole piece safety coating 5-4 arranged on the outer surface of the first pole piece metal oxide layer 5-3, and the first pole piece safety coating 5-4 completely covers the surface and the side surface of the first pole piece metal oxide layer 5-3; the second pole piece 6 is a pole piece according to the first aspect of the present utility model, the second pole piece 6 includes a second pole piece current collector 6-1, second pole piece active material coatings 6-2 disposed on two side surfaces of the second pole piece current collector 6-1, a second pole piece metal oxide layer 6-3 disposed on an outer surface of the second pole piece active material coatings 6-2, and a second pole piece safety coating 6-4 disposed on an outer surface of the second pole piece metal oxide layer 6-3.
In the utility model, at least one of the first pole piece and the second pole piece of the battery is the pole piece.
For example, the first pole piece of the battery is the pole piece according to the first aspect of the utility model, and the second pole piece is a negative pole piece conventionally used in the art.
As shown in fig. 11, in one example, the battery includes a first pole piece 5 and a second pole piece 6; the first pole piece 5 is the pole piece according to the first aspect of the present utility model, the first pole piece 5 comprises a first pole piece current collector 5-1, first pole piece active material coatings 5-2 arranged on two side surfaces of the first pole piece current collector 5-1, a first pole piece metal oxide layer 5-3 arranged on the outer surface of the first pole piece active material coatings 5-2, and a first pole piece safety coating 5-4 arranged on the outer surface of the first pole piece metal oxide layer 5-3, and the first pole piece safety coating 5-4 completely covers the surface and the side surface of the first pole piece metal oxide layer 5-3; the second electrode sheet 6 is a cathode sheet conventionally used in the art, and the second electrode sheet 6 includes a second electrode sheet current collector 6-1 and second electrode sheet active material coatings 6-2 disposed on both side surfaces of the second electrode sheet current collector 6-1.
For another example, the second pole piece of the battery is the pole piece according to the first aspect of the utility model, and the first pole piece is a positive pole piece conventionally used in the art.
As shown in fig. 12, in one example, the battery includes a first pole piece 5 and a second pole piece 6; the first pole piece 5 is a first pole piece conventionally used in the field, and the first pole piece 5 comprises a first pole piece current collector 5-1 and first pole piece active material coatings 5-2 arranged on the two side surfaces of the first pole piece current collector 5-1; the second electrode sheet 6 is a cathode sheet conventionally used in the art, and the second electrode sheet 6 comprises a second electrode sheet current collector 6-1, second electrode sheet active material coatings 6-2 arranged on two side surfaces of the second electrode sheet current collector 6-1, a second electrode sheet metal oxide layer 6-3 arranged on the outer surface of the second electrode sheet active material coatings 6-2, and a second electrode sheet safety coating 6-4 arranged on the outer surface of the second electrode sheet metal oxide layer 6-3.
The battery may be a wound battery or a laminated battery.
In one example, the battery is a wound battery.
The present utility model will be described in detail by examples. The described embodiments of the utility model are only some, but not all, embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
The following group I examples are presented to illustrate the pole pieces of the present utility model.
Example I1
The preparation of the pole piece at least comprises the following steps:
(1) Active material layer:
active material: 96.5% by weight of lithium cobaltate;
a first conductive agent: conductive carbon black SP,2% by weight;
a first binder: polyvinylidene fluoride, 1.5% by weight;
mixing active substance, first conductive agent and first binder, adding N-methyl pyrrolidone, stirring, coating on the outer surfaces of two sides of aluminum foil with solid content of 70%, and drying in oven at 80deg.C.
(2) Metal oxide layer:
lithium compound: li (Li) 5 FeO 4 97% by weight;
and a second conductive agent: conductive carbon black SP,2% by weight;
and a second binder: polyvinylidene fluoride, 1% by weight;
mixing lithium compound, second conductive agent and second binder, adding N-methyl pyrrolidone, stirring, coating on the outer surface of active material layer with solid content of 50%, and drying in oven at 80deg.C.
(3) And (3) safety coating:
ion conductive ceramics: garnet-type electrolyte Li 6.4 La 3 Zr 2 Al 0.2 O 12 97.92% by weight;
nanofiber: 1.08% by weight of carbon nanofibers;
and a third binder: 0.9% by weight of polyvinylidene fluoride;
mixing ion conductive ceramic, nanofiber and a third binder, adding N-methyl pyrrolidone, stirring uniformly, wherein the solid content is 70%, coating the side surface of a current collector, the side surface of an active material layer and the surface and the side surface of a lithium supplementing agent, and drying in an oven at 80 ℃.
The positive electrode sheet was obtained, wherein the porosity of the metal oxide layer was 30%, the thickness of the metal oxide layer was 12 μm, the porosity of the safety coating layer was 45%, the thickness of the safety coating layer was 14 μm, and the thickness of the safety coating layer was 7% of the total thickness of the sheet (the thickness of the active material coating layer was 69 μm, and the thickness of the aluminum foil was 10 μm).
Example I2
The procedure of example I1 was followed, except that the ratio of the lithium compound, the second conductive agent and the second binder in the metal oxide layer was changed and the thicknesses of the active material coating layer, the metal oxide layer and the safety coating layer were changed, specifically: the porosity of the metal oxide layer was 45%, the thickness of the metal oxide layer was 4 μm, the porosity of the safety coating was 45%, the thickness of the safety coating was 8 μm, and the thickness of the safety coating was 5% of the total thickness of the pole piece (thickness of the active material coating was 63 μm, and thickness of the aluminum foil was 10 μm).
Example I3
The procedure of example I1 was followed, except that the ratio of the ion-conductive ceramic, nanofibers and the third binder in the security coating was varied and the thicknesses of the active material coating, the metal oxide layer and the security coating were varied, specifically: the porosity of the metal oxide layer is 30%, the thickness of the metal oxide layer is 20 μm, the porosity of the safety coating is 60%, the thickness of the safety coating is 20 μm, the thickness of the safety coating accounts for 10% of the total thickness of the pole piece (the thickness of the active material coating is 55 μm, and the thickness of the aluminum foil is 10 μm).
Example I4
The procedure of example I1 was followed except that the resulting electrode sheet was a negative electrode sheet, specifically, the active material was graphite, and the aluminum foil was replaced with copper foil of the same thickness.
Example I5
This set of embodiments is used to illustrate the effect of changing the cladding area of the security coating.
This set of examples is performed with reference to the procedure of example I1, except that the cladding area of the security coating is changed.
In example I5a, the safety coating is applied to the surface and sides of the lithium supplement.
In embodiment I5b, the safety coating layer is coated on the side of the active material layer and the surface and side of the lithium supplementing agent.
Example I6
This set of embodiments is used to illustrate the effect of the thickness of the security coating and/or the change in the ratio of the thickness of the security coating to the thickness of the pole piece.
This set of examples is performed with reference to the steps of example I1, except that the thickness of the security coating and/or the ratio of the thickness of the security coating to the thickness of the pole piece is varied.
In example I6a, the thickness of the security coating was 6 μm, the thickness of the security coating was 3.3% of the total thickness of the pole piece;
in example I6b, the thickness of the security coating was 28 μm, the thickness of the security coating being 12.3% of the total thickness of the pole piece.
Comparative example D1
Referring to example I1, except that the metal oxide layer and the safety coating layer were not included, i.e., the outer surfaces of both sides of the aluminum foil were provided with only the active material layer.
Comparative example D2
Referring to example I4, except that the metal oxide layer and the safety coating layer were not included, i.e., only the active material layer was provided on the outer surfaces of both sides of the copper foil.
Example II
The following group II examples serve to illustrate the cells of the present utility model.
Preparing an electrolyte: propylene carbonate and ethylene carbonateMixing dimethyl carbonate and methyl ethyl carbonate according to the mass ratio of 1:1:0.5:1, and adding 1mol/L LiPF 6 Mixing well.
And winding the positive plate, the negative plate and the optional separator to prepare the battery, wherein the specific choices of the positive plate, the negative plate and the optional separator are shown in table 1.
TABLE 1
Test case
(1) Safety performance test
The batteries obtained in group II examples and comparative examples were subjected to a needling test, the batteries did not fire and did not explode, i.e., passed, or failed, wherein,
the specific test method of the needling test comprises the following steps: full cell, use diameter phi (3+ -0.5) mm high temperature resistant steel needle (conical angle of needle point is 45 deg.C-60 deg.C, needle surface is smooth and clean, no rust, no oxide layer and no oil dirt), run through from the direction perpendicular to cell polar plate at the speed of (100 mm+ -5 mm/s), puncture position is preferably close to geometric center of punctured face (steel needle stays in cell). The test was stopped by observing the decrease of the highest temperature of the cell surface to the peak temperature of 10 ℃ or less for 1 hour, and 10 tests were performed for each group of cells, and the test results are shown in table 2.
(2) Multiplying power test
Charging and discharging at normal temperature multiplying power: 2.0C off-current 0.025C, discharge current 0.7C, capacity percentage = discharge capacity/charge capacity, test results are reported in table 2.
(3) First coulombic efficiency test
1. Standing for 10min;
charging for 10min at 2.30 mA;
3. standing for 10min;
4.0.1C constant current is charged to the upper limit cutoff voltage, and the cutoff current is 10mA;
5. standing for 10min;
6.0.1C is discharged to the discharge end voltage.
The test results are shown in Table 2.
TABLE 2
| Safety performance test | Multiplying power (capacity percentage) | First coulombic efficiency | |
| Example II1 | 9pass/10 | 91％ | 93％ |
| Example II2 | 9pass/10 | 92％ | 91％ |
| Example II3 | 10pass/10 | 89％ | 94％ |
| Example II4 | 10pass/10 | 89％ | 92％ |
| Example II5a | 9pass/10 | 91％ | 93％ |
| Example II5b | 9pass/10 | 91％ | 93％ |
| Example II6a | 8pass/10 | 92％ | 94％ |
| Example II6b | 10pass/10 | 88％ | 92％ |
| Example II7 | 6pass/10 | 92％ | 89％ |
| Example II8 | 6pass/10 | 92％ | 91％ |
| Comparative example DD1 | 3pass/10 | 87％ | 85％ |
| Comparative example DD2 | 1pass/10 | 88％ | 86％ |
As can be seen from Table 2, compared with the comparative example, the battery prepared by the pole piece of the utility model has the advantages that the needling test passing rate, multiplying power and first coulomb efficiency are all obviously improved, the safety performance of the battery is obviously improved, and the first coulomb efficiency of the battery is improved.
The preferred embodiments of the present utility model have been described in detail above, but the present utility model is not limited thereto. Within the scope of the technical idea of the utility model, a number of simple variants of the technical solution of the utility model are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the utility model, all falling within the scope of protection of the utility model.
Claims (10)
1. The pole piece is characterized by comprising a current collector, an active material coating arranged on one side or two side surfaces of the current collector, a metal oxide layer arranged on the outer surface of the active material coating and a safety coating arranged on the outer surface of the metal oxide layer, wherein the safety coating completely covers the surface and the side surface of the metal oxide layer.
2. The pole piece of claim 1, wherein the safety coating completely covers the surface and sides of the metal oxide layer and the sides of the active material coating.
3. The pole piece of claim 1, wherein the safety coating completely covers the surface and sides of the pole piece.
4. A pole piece according to any of claims 1-3, characterized in that the thickness of the safety coating is 2-48% of the total thickness of the pole piece.
5. A pole piece according to any of claims 1-3, characterized in that the thickness of the metal oxide layer is 2-40 μm and the thickness of the security coating is 5-30 μm.
6. A pole piece according to any of claims 1-3, characterized in that the porosity of the metal oxide layer is 20-80% and the porosity of the safety coating is 20-80%.
7. The pole piece of claim 6, wherein the ratio of the porosity of the metal oxide layer to the porosity of the security coating is 1 (0.25-4).
8. A battery comprising a pole piece according to any one of claims 1-7.
9. The battery of claim 8, wherein the battery comprises a first pole piece and a second pole piece, at least one of the first pole piece and the second pole piece being the pole piece, and the first pole piece and the second pole piece being separated by the safety coating.
10. The battery of claim 9, wherein the battery is a wound battery or a laminated battery.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223419676.3U CN219303705U (en) | 2022-12-20 | 2022-12-20 | Pole piece and battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223419676.3U CN219303705U (en) | 2022-12-20 | 2022-12-20 | Pole piece and battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN219303705U true CN219303705U (en) | 2023-07-04 |
Family
ID=86952712
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202223419676.3U Active CN219303705U (en) | 2022-12-20 | 2022-12-20 | Pole piece and battery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN219303705U (en) |
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2022
- 2022-12-20 CN CN202223419676.3U patent/CN219303705U/en active Active
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