CN218039279U - Positive plate and battery - Google Patents
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- CN218039279U CN218039279U CN202221455527.XU CN202221455527U CN218039279U CN 218039279 U CN218039279 U CN 218039279U CN 202221455527 U CN202221455527 U CN 202221455527U CN 218039279 U CN218039279 U CN 218039279U
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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
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The utility model provides a positive plate and battery, positive plate include the mass flow body and set up the utmost point ear at the tip of the mass flow body, and the length direction mass flow body along the mass flow body includes middle zone and marginal area, and marginal area is for being close to the region of utmost point ear, and the mass flow body back of the body mutually in middle zone and marginal area is provided with the active material layer respectively in both sides mutually, and it has the phase change material layer to cover on the active material layer of marginal area. In this way, the phase change material layer is arranged in the edge area, in other words, the active material layer close to the tab is covered with the phase change material layer to fill the vacant part of the active material layer in the edge area, and the phase change material layer can absorb the heat gathered at the end part of the current collector to reduce the temperature; and the phase-change material layer is not covered on the middle area, namely the active material layer far away from the pole ear, so that the proportion of the active material layer is increased, and the energy density is improved.
Description
Technical Field
The utility model relates to a battery technology field especially relates to a positive plate and battery.
Background
Lithium ion batteries are widely used because of their advantages of high energy density, long cycle life, low self-discharge, no memory effect, etc. As people seek shorter and shorter charging times, charging currents are also larger and larger, so that a large amount of heat is accumulated inside the lithium ion battery. Especially, on the top of the battery core, the top of the battery core is always higher than the temperature of other areas due to the reasons of thinning areas, over-current of tabs and the like in the pasting process on the top of the battery core, the higher the temperature is, the faster the side reaction on the surface of the positive electrode material is, the aggravation of battery expansion and the easy occurrence of safety accidents.
At present, a heat absorbing material is generally arranged on the surface of a foil, but the thickness of an aluminum foil or a copper foil of the battery is also increased, so that the energy density of the battery is reduced.
It can be seen that the batteries in the prior art have the problem of low energy density.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a positive plate and battery to solve the lower problem of battery energy density among the prior art.
The embodiment of the utility model provides a positive plate, be in including current collector and setting the utmost point ear of the tip of current collector is followed the length direction of current collector the current collector includes middle region and marginal area, marginal area is for being close to the region of utmost point ear middle region with marginal area the current collector carries on the back both sides mutually and is provided with active material layer respectively edge area's active material layer coats and is stamped the phase change material layer.
Optionally, the thickness of the active material layer in the edge region is smaller than that in the intermediate region, and the thickness of the phase change material layer increases in a direction toward the tab.
Optionally, the thickness of the active material layer in the middle region is greater than or equal to the sum of the thickness of the active material layer in the edge region and the thickness of the phase change material layer.
Optionally, the phase change material layer includes a first portion disposed on the active material layer in the edge region, and a second portion extending from the first portion to the tab direction onto the current collector.
Optionally, the active material layer in the edge region extends along the length direction of the current collector in a length range of 0.1 mm to 15 mm, and the phase change material layer extends along the length direction of the current collector in a length range of 0.1 mm to 20 mm.
Optionally, the phase change material layer has a thickness in a range of 0.1 to 10 microns.
Optionally, the phase change material layer includes a nanocapsule, the nanocapsule includes a capsule core and a capsule wall, the capsule core is disposed in the capsule wall, the capsule core is used for absorbing heat, and the capsule wall is an organic material capsule wall or an inorganic material capsule wall.
Optionally, the nanocapsule has a phase transition temperature in a range of 15 to 100 degrees celsius, a particle size in a range of 0.05 to 1 micron, and an enthalpy change value in a range of 50 to 200J/g.
Optionally, the active material layer includes an active material, a binder, a conductive agent, and/or a solvent.
The embodiment of the utility model provides a still provide a battery, including foretell positive plate.
In the embodiment of the utility model, the water-soluble,
the phase change material layer is arranged in the edge area, in other words, the active material layer close to the pole ear is covered with the phase change material layer to fill the vacant part of the active material layer in the edge area, and the phase change material layer can absorb the heat gathered at the end part of the current collector and reduce the temperature; and the phase change material layer is not covered on the middle area, namely the active material layer far away from the pole ear, so that the proportion of the active material layer is increased, and the energy density is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the embodiments or the prior art description will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without inventive labor.
Fig. 1 is one of schematic structural diagrams of a positive plate provided in an embodiment of the present invention;
fig. 2 is a second schematic structural diagram of the positive plate according to the embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, of the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
The terms "first," "second," and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be understood that the structures so used are interchangeable under appropriate circumstances such that embodiments of the invention can be practiced in sequences other than those illustrated or described herein, and the terms "first," "second," and the like are generally used herein in a generic sense without limitation to the number of terms, e.g., the first term can be one, or more than one.
The embodiment of the utility model provides a positive plate, as shown in fig. 1 and fig. 2, including the mass flow body 10 and set up the utmost point ear at the tip of the mass flow body 10, the length direction mass flow body 10 along the mass flow body 10 includes middle zone and edge area, and edge area can be the region that is close to utmost point ear, is provided with active material layer 20 respectively in middle zone and edge area's the mass flow body 10 both sides that carry on the back mutually, coats on the active material layer 20 of edge area and is stamped phase change material layer 30.
In this embodiment, the active material layer 20 may be coated on the opposite surfaces of the current collector 10, and the phase change material layer 30 is disposed in the edge region, in other words, the active material layer 20 near the tab is covered with the phase change material layer 30 to fill the vacant part of the active material layer 20 in the edge region, and the phase change material layer 30 may absorb the heat collected at the end of the current collector 10 to reduce the temperature; and the phase change material layer 30 is not covered on the middle area, namely the active material layer 20 far away from the pole ear, so that the proportion of the active material layer 20 is increased, and the energy density is improved.
Alternatively, the thickness of the active material layer 20 at the edge region is smaller than that of the active material layer 20 at the middle region, and the thickness of the phase change material layer 30 increases in the direction toward the tab.
In the present embodiment, the thickness of the active material layer 20 in the edge region is smaller than that of the active material layer 20 in the middle region, the thickness of the active material layer 20 in the edge region may decrease in the direction toward the tab, and the thickness of the phase change material layer 30 may increase in the direction toward the tab, so as to fill the portion of the active material layer 20 that is missing in the edge region.
In the case of high-rate charge and discharge, a large amount of heat is generated inside the lithium ion battery, especially at a position close to a tab, so that the thickness of the phase change material layer 30 increases progressively along the length direction of the current collector 10, and at a position closest to the tab, the thickness of the phase change material layer 30 can have a maximum value to absorb the heat collected at the end of the current collector 10, thereby reducing the temperature, reducing the side reaction rate of the active material layer 20 in the edge region, reducing the abnormal expansion condition, and prolonging the cycle life.
Alternatively, the thickness of the active material layer 20 in the middle region is equal to or greater than the sum of the thickness of the active material layer 20 in the edge region and the thickness of the phase change material layer 30.
In this embodiment, the active material layer 20 is coated on the current collector 10, the thickness of the active material layer 20 decreases in the edge region, the phase change material layer 30 is disposed on the active material layer 20 in the edge region, and heat generated at the tab may be absorbed by the phase change material layer 30 during the charge and discharge cycle; in addition, the phase change material layer 30 is not covered on the active material layer 20 in the middle region, and the thickness of the active material layer 20 in the middle region is greater than or equal to the sum of the thickness of the active material layer 20 in the edge region and the thickness of the phase change material layer 30, so that the phase change material layer 30 can be filled in the vacant part of the active material layer 20 in the edge region, and the energy density is improved.
It should be noted that the maximum thickness of the active material layer 20 may be the sum of the thickness of the active material layer 20 in the edge region and the thickness of the phase change material layer 30, in other words, the thickness of the active material layer 20 in the middle region may have a maximum value, and is equal to the sum of the thickness of the active material layer 20 in the edge region and the thickness of the phase change material layer 30, so that the covering thickness on the same side of the current collector 10 is the same, so that the stress of the positive electrode sheet is uniform, and the occurrence of side reactions is reduced.
However, in an actual coating process, the coating thickness of the active material layer 20 has a certain error, and it is difficult to achieve a completely flat state. In this way, the thickness of the active material layer 20 in the middle region is greater than the sum of the thickness of the active material layer 20 in the edge region and the thickness of the phase change material layer 30, and the phase change material layer 30 can also fill the vacant part of the active material layer 20 in the edge region, thereby increasing the energy density.
In some alternative embodiments, the active material layer 20 at the edge region may extend along the length direction of the current collector 10 by a length ranging from 0.1 mm to 15 mm, and the phase change material layer 30 may extend along the length direction of the current collector 10 by a length ranging from 0.1 mm to 20 mm.
The active material layer 20 may be symmetrically disposed on two opposite sides of the current collector 10, tabs are disposed on the end surface of the current collector 10, and the active material layer 20 in the edge area, that is, the active material layer 20 close to the end surface of the current collector 10, is covered with the phase change material layer 30 to fill the vacant part on the active material layer 20 in the edge area. The active material layer 20 may be coated first and then the phase change material layer 30 may be coated on the active material layer 20 at the edge region.
The thickness of the active material layer 20 on one side of the current collector 10 may be 50 micrometers to 200 micrometers, the active material layer 20 located near the tab, that is, the length of the active material layer 20 in the edge region extending along the length direction of the current collector 10 may be 0.1 mm to 15 mm, and the thinning thickness of the active material layer 20 in the edge region may be 0.1 micrometers to 10 micrometers compared to the active material layer 20 in the middle region.
Wherein a length of the phase change material layer 30 extending along a length direction of the current collector 10 may be in a range of 0.1 mm to 20 mm; the thickness of the phase change material layer 30 may range from 0.1 to 10 micrometers, and the coating thickness of the phase change material layer 30 may be adjusted according to the thickness of the active material layer 20 of the edge region to fill the vacant part on the active material layer 20.
Specifically, the maximum thickness of the active material layer 20 may be 70 micrometers; the width of the active material layer 20 in the edge region may be 4mm to 8 mm; the thinning thickness may be 2 to 8 micrometers, that is, the thickness of the phase change material layer 30 may be 2 to 8 micrometers, so as to fill the thinning thickness, reduce the side reaction rate of the active material layer 20 in the edge region, and reduce the abnormal expansion. The provision of the phase change material layer 30 is reduced on the active material layer 20 in the intermediate region, increasing the proportion of the active material layer 20, thereby increasing the energy density.
In other alternative embodiments, the phase change material layer 30 may include a first portion disposed on the active material layer 20 in the edge region and a second portion extending from the first portion to the current collector 10 in the tab direction. In other words, a first portion of the phase change material layer 30 is coated on the active material layer 20 in the edge region, and a second portion of the phase change material layer 30 extends along the length direction of the current collector 10 and is coated on the current collector 10 near the tab, so as to further absorb the heat collected at the end of the current collector 10, reduce the temperature, reduce the side reaction rate, reduce the abnormal expansion, and prolong the cycle life.
Alternatively, the active material layer 20 may include a positive electrode active material, a binder, a conductive agent, and/or a solvent.
The positive active substance can comprise one or more of a nickel cobalt lithium manganate ternary material, a lithium cobaltate material, a nickel cobalt lithium aluminate material, a lithium manganate material, a lithium iron phosphate material and a lithium-rich manganese-based material;
the binder can be one or a mixture of polyvinylidene fluoride, polytetrafluoroethylene, styrene butadiene rubber, sodium carboxymethylcellulose, polyimide or polyethylene;
the conductive agent can be one or a mixture of more of conductive ceramics, carbon black, graphite, graphene, polyaniline, polypyrrole, ketjen black, acetylene black and carbon nanotubes;
the solvent can be one or more of N-methyl pyrrolidone, water, ethanol and polyethylene glycol.
Specifically, the current collector 10 may be an aluminum foil, the positive active material may be a lithium iron phosphate material, the binder may be polyvinylidene fluoride, the conductive agent may be carbon black, and the solvent may be N-methyl pyrrolidone, so as to improve the conductivity of the positive plate.
Alternatively, the phase change material layer 30 may comprise a nanocapsule, the nanocapsule comprising a core disposed within the wall, the core being adapted to absorb heat, and a wall, which may be an organic material wall or an inorganic material wall.
Wherein, the capsule core of the micro-nano capsule can be one or a mixture of paraffin, fatty acid, polyethylene glycol, eicosane and the like. The nanocapsules may have a phase transition temperature in the range of 15 to 100 degrees celsius, a particle size in the range of 0.05 to 1 micron, and a enthalpy change value in the range of 50 to 200J/g.
For example, the capsule core can be fatty acid or a mixture of paraffin and polyethylene glycol to enhance the stability of the nanocapsule, reduce the phase transition temperature, and have a phase transition at 25 ℃, an enthalpy change value of more than 150J/g, so as to better absorb heat collected at the end of the current collector 10 during charging and discharging and maintain internal temperature balance.
The capsule wall of the micro-nano capsule can be an organic material capsule wall or an inorganic material capsule wall which is acid-base resistant, strong in inertia and free from physical and chemical reactions with electrolyte and positive active substances.
The organic material capsule wall can be one or more of polyethylene, ethylene vinyl acetate, polymethyl methacrylate, polyurethane, urea, polystyrene, phenolic resin, urea-formaldehyde resin, polyamide resin, epoxy resin and the like;
the inorganic material capsule wall can be one or more of titanium dioxide, silicon dioxide, aluminum oxide, magnesium oxide, silicon oxide and zirconium oxide.
For example, the capsule wall may comprise polystyrene or polyurethane, which has high material strength, strong chemical inertness, and good chemical compatibility with the positive and negative active materials of the lithium battery, and does not leak and contaminate the inside of the battery.
The embodiment of the utility model provides a still provide a battery, this battery includes foretell positive plate. The positive plate can be realized in various embodiments, and the same beneficial effects can be achieved, and the details are not repeated herein to avoid repetition.
Next, effects of the positive electrode sheet provided by the present invention will be described based on the test experiments of reference example 1, and examples 1 to 4.
Reference example 1:
step 1, preparing a positive plate P0 coated with an active material layer 20;
stirring and mixing a lithium iron phosphate (LFP) material serving as a positive electrode active material, a polyvinylidene fluoride binder and a carbon black serving as a conductive agent according to the weight ratio of 95wt% to 2wt% to 3wt%, adding a N-methyl pyrrolidone solvent, mixing, shearing and stirring to form a uniformly dispersed slurry mixture solution, wherein the solid content of the slurry is 65%. After the slurry is uniformly mixed, the slurry is uniformly coated on both sides of the aluminum foil of the current collector 10, the thickness of one side of the active material layer 20 is 70 μm, the width of the active material layer 20 in the edge area is 8mm, and the thinning thickness is 6 μm. And drying and rolling the pole piece to obtain the positive pole piece P0.
Step 2, preparing a battery C0;
and (3) laminating and packaging the positive plate P0 obtained in the step (1), the negative plate and the diaphragm, injecting electrolyte, forming, secondary sealing and capacity grading, then placing the battery on the bench to obtain a battery C0, and immediately carrying out performance testing on the battery C0.
Example 1:
step 1, preparing a positive plate P1 coated with an active material layer 20;
stirring and mixing a lithium iron phosphate (LFP) material serving as a positive electrode active material, a polyvinylidene fluoride binder and a carbon black serving as a conductive agent according to the weight ratio of 95wt% to 2wt% to 3wt%, adding a N-methyl pyrrolidone solvent, mixing, shearing and stirring to form a uniformly dispersed slurry mixture solution, wherein the solid content of the slurry is 65%. After the slurry is uniformly mixed, the slurry is uniformly coated on both sides of the aluminum foil of the current collector 10, the thickness of one side of the active material layer 20 is 70 μm, the width of the active material layer 20 in the edge area is 8mm, and the thinning thickness is 6 μm. And drying and rolling the pole piece to obtain the positive pole piece P1.
Step 2, preparing a positive plate P1 coated with a phase-change material layer 30;
adding the phase change micro-nano capsule with the phase change temperature of 25 ℃ and the D50 particle size of 0.1 mu m into a solvent N-methyl pyrrolidone, mixing, shearing and stirring to form a phase change material solution which is uniformly mixed and contains 5% of solid, uniformly coating the phase change material solution on the edge area of the positive plate P1 obtained in the step 1, wherein the coating width is 8mm, and the coating thickness is 6 mu m. The capsule core of the phase-change material is a mixture of paraffin and polyethylene glycol, and the capsule wall of the phase-change material is polystyrene. And drying and cutting the obtained pole piece to obtain the positive pole piece P1.
Step 3, preparing a battery C1;
and (3) laminating and packaging the positive plate P1 obtained in the step (2), the negative plate and the diaphragm, injecting electrolyte, forming, secondary sealing and capacity grading, then discharging to obtain the battery C1, and performing performance test on the battery C.
Example 2:
step 1: preparing a positive electrode sheet P2 coated with an active material layer 20;
stirring and mixing 95wt% of lithium iron phosphate (LFP) material as a positive active material, 2wt% of polyvinylidene fluoride as a binder and 3wt% of carbon black as a conductive agent, adding N-methyl pyrrolidone as a solvent, mixing, shearing and stirring to form a uniformly dispersed slurry mixture solution, wherein the solid content of the slurry is 65%. After the slurry is uniformly mixed, the slurry is uniformly coated on both sides of the aluminum foil of the current collector 10, the thickness of one side of the active material layer 20 is 70 μm, the width of the active material layer 20 in the edge area is 4mm, and the thinning thickness is 8 μm. And drying and rolling the pole piece to obtain the positive pole piece P2.
Step 2, preparing a positive plate P2 coated with a phase-change material layer 30;
adding the phase change micro-nano capsule with the phase change temperature of 25 ℃ and the D50 particle size of 0.1 mu m into a solvent N-methyl pyrrolidone, mixing, shearing and stirring to form a phase change material solution which is uniformly mixed and contains 5% of solid, uniformly coating the phase change material solution on the edge area of the positive plate P2 obtained in the step 1, wherein the coating width is 4mm, and the coating thickness is 8 mu m. The capsule core of the phase-change material is a mixture of paraffin and polyethylene glycol, and the capsule wall of the phase-change material is polystyrene. And drying and cutting the obtained pole piece to obtain the positive pole piece P2.
Step 3, preparing a battery C2;
and (3) laminating and packaging the positive plate P2 obtained in the step (2), the negative plate and the diaphragm, injecting electrolyte, forming, secondary sealing and capacity grading, then placing the battery on the bench to obtain a battery C2, and then testing the performance of the battery C.
Example 3:
step 1, preparing a positive plate P3 coated with an active material layer 20;
stirring and mixing a lithium iron phosphate (LFP) material serving as a positive electrode active material, a polyvinylidene fluoride binder and a carbon black serving as a conductive agent according to the weight ratio of 95wt% to 2wt% to 3wt%, adding a N-methyl pyrrolidone solvent, mixing, shearing and stirring to form a uniformly dispersed slurry mixture solution, wherein the solid content of the slurry is 65%. After the slurry is uniformly mixed, the slurry is uniformly coated on both sides of the aluminum foil of the current collector 10, the thickness of one side of the active material layer 20 is 70 μm, the width of the active material layer 20 in the edge area is 8mm, and the thinning thickness is 6 μm. And drying and rolling the pole piece to obtain the positive pole piece P3.
Step 2, preparing a positive plate P3 coated with a phase-change material layer 30;
adding the phase change micro-nano capsule with the phase change temperature of 25 ℃ and the D50 particle size of 0.1 mu m into a solvent N-methyl pyrrolidone, mixing, shearing and stirring to form a phase change material solution which is uniformly mixed and contains 5% of solid, uniformly coating the phase change material solution on the edge area of the positive plate P3 obtained in the step 1, wherein the coating width is 8mm, and the coating thickness is 6 mu m. The core of the phase-change material is fatty acid, and the wall of the phase-change material is polystyrene. And drying and cutting the obtained pole piece to obtain the positive pole piece P3.
Step 3, preparing a battery C3;
and (3) laminating and packaging the positive plate P3 obtained in the step (2), the negative plate and the diaphragm, injecting electrolyte, forming, secondary sealing and capacity grading, then discharging to obtain a battery C3, and performing performance test on the battery C.
Example 4:
step 1, preparing a positive plate P4 coated with an active material layer 20;
stirring and mixing a lithium iron phosphate (LFP) material serving as a positive electrode active material, a polyvinylidene fluoride binder and a carbon black serving as a conductive agent according to the weight ratio of 95wt% to 2wt% to 3wt%, adding a N-methyl pyrrolidone solvent, mixing, shearing and stirring to form a uniformly dispersed slurry mixture solution, wherein the solid content of the slurry is 65%. After the slurry is uniformly mixed, the slurry is uniformly coated on both sides of the aluminum foil of the current collector 10, the thickness of one side of the active material layer 20 is 70 μm, the width of the active material layer 20 in the edge area is 8mm, and the thinning thickness is 6 μm. And drying and rolling the pole piece to obtain the positive pole piece P1.
Step 2, preparing a positive plate P4 coated with a phase-change material layer 30;
adding the phase change micro-nano capsule with the phase change temperature of 25 ℃ and the D50 particle size of 0.1 mu m into a solvent N-methyl pyrrolidone, mixing, shearing and stirring to form a phase change material solution which is uniformly mixed and contains 5% of solid, uniformly coating the phase change material solution on the edge area of the positive plate P4 obtained in the step 1, wherein the coating width is 8mm, and the coating thickness is 6 mu m. The capsule core of the phase-change material is fatty acid, and the capsule wall of the phase-change material is polyurethane. And drying and cutting the obtained pole piece to obtain the positive pole piece P4.
Step 3, preparing a battery C4;
and (3) laminating and packaging the positive plate P4 obtained in the step (2), the negative plate and the diaphragm, injecting electrolyte, forming, secondary sealing and capacity grading, then placing the battery on the bench to obtain a battery C4, and then testing the performance of the battery C4.
The material performance test was performed on the reference example 1 and the examples 1 to 4, and the test procedure was as follows:
the batteries of reference example 1 and examples 1 to 4 were charged at a constant current of 2C rate at 25 ℃, the cutoff current was 0.05C rate, and then discharged at a constant current of 2C rate, the voltage range was 2.0 to 3.65V, which is a charge-discharge cycle, and the temperature rise of the head thinning region (active material layer 20 in the edge region) of the battery, the temperature rise of the battery body, and the expansion rate of the battery after 1000 cycles were recorded and compared, and the data are shown in table 1.
TABLE 1 lithium ion cell Performance test Table
From the above data, it can be seen that the temperature rise of the thinned region of the battery head without the phase change material layer 30 in reference example 1 is about 4 ℃ higher than the temperature rise of the battery body, while the temperature difference of the battery examples 1 to 4 coated with the phase change material layer 30 is small, only 0 to 1 ℃, the temperature of the battery body is basically balanced, and the situation of local overheating does not occur. It can be seen from the expansion rate data after 1000 cycles that the expansion rate of reference example 1 reaches 8.7% and the expansion rate of examples 1 to 4% is only about 3 to 4% due to the long-term high temperature environment of the battery head, which has a relatively obvious effect.
Thus, the phase change material layer 30 is not coated on the intermediate region, i.e., the active material layer 20 away from the tab, to increase the ratio of the active material layer 20, thereby increasing the energy density. And the phase change material layer 30 is arranged in the edge region, in other words, the active material layer 20 close to the tab is covered with the phase change material layer 30, the thickness of the phase change material layer 30 can be increased along the length direction of the current collector 10 to absorb the heat gathered at the end of the current collector 10, so as to reduce the temperature, thereby reducing the side reaction rate of the active material layer 20 in the edge region, reducing the abnormal expansion condition and prolonging the cycle life.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one of 8230, and" comprising 8230does not exclude the presence of additional like elements in a process, method, article, or apparatus comprising the element. Furthermore, it should be noted that the scope of the methods and apparatus of the embodiments of the present invention is not limited to performing functions in the order discussed, but may include performing functions in a substantially simultaneous manner or in a reverse order based on the functions involved, e.g., the methods described may be performed in an order different than that described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.
The embodiments of the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the above-mentioned embodiments, which are only illustrative and not restrictive, and those skilled in the art can make many forms without departing from the spirit and scope of the present invention.
Claims (9)
1. The utility model provides a positive plate, its characterized in that is in including the mass flow body and setting the utmost point ear of the tip of the mass flow body follows the length direction of the mass flow body includes middle region and marginal area, marginal area is for being close to the region of utmost point ear middle region with marginal area the mass flow body both sides mutually back of the body are provided with the active material layer respectively the active material layer of marginal area coats and is stamped the phase change material layer.
2. The positive electrode sheet according to claim 1, wherein the thickness of the active material layer in the edge region is smaller than the thickness of the active material layer in the intermediate region, and the thickness of the phase change material layer increases in a direction toward the tab.
3. The positive electrode sheet according to claim 2, wherein the thickness of the active material layer in the intermediate region is equal to or greater than the sum of the thickness of the active material layer in the edge region and the thickness of the phase change material layer.
4. The positive electrode sheet according to claim 1, wherein the phase change material layer includes a first portion disposed on the active material layer in the edge region, and a second portion extending from the first portion to the tab direction onto the current collector.
5. The positive electrode sheet according to claim 1, wherein the active material layer at the edge region has a length extending in a lengthwise direction of the current collector in a range of 0.1 mm to 15 mm, and the phase change material layer has a length extending in the lengthwise direction of the current collector in a range of 0.1 mm to 20 mm.
6. The positive electrode sheet according to claim 1, wherein the phase change material layer has a thickness in a range of 0.1 to 10 micrometers.
7. The positive plate according to claim 1, wherein the phase change material layer comprises a nanocapsule, the nanocapsule comprises a capsule core and a capsule wall, the capsule core is arranged in the capsule wall and is used for absorbing heat, and the capsule wall is an organic material capsule wall or an inorganic material capsule wall.
8. The positive plate according to claim 7, wherein the nanocapsule has a phase transition temperature in a range of 15 to 100 degrees Celsius, a particle size in a range of 0.05 to 1 micron, and an enthalpy change value in a range of 50 to 200J/g.
9. A battery comprising the positive electrode sheet according to any one of claims 1 to 8.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116230856A (en) * | 2023-05-08 | 2023-06-06 | 宁德时代新能源科技股份有限公司 | Positive pole piece, battery and electric equipment |
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2022
- 2022-06-10 CN CN202221455527.XU patent/CN218039279U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116230856A (en) * | 2023-05-08 | 2023-06-06 | 宁德时代新能源科技股份有限公司 | Positive pole piece, battery and electric equipment |
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