CN217507394U - Pole piece, electric core and battery - Google Patents
Pole piece, electric core and battery Download PDFInfo
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- CN217507394U CN217507394U CN202123419843.XU CN202123419843U CN217507394U CN 217507394 U CN217507394 U CN 217507394U CN 202123419843 U CN202123419843 U CN 202123419843U CN 217507394 U CN217507394 U CN 217507394U
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Abstract
The utility model provides a pole piece, electric core and battery, the pole piece includes: a current collector comprising a first conductive layer, a second conductive layer, and an insulating layer, the insulating layer being located between the first conductive layer and the second conductive layer; a first active material layer provided on a surface of the first conductive layer away from the insulating layer; a second active material layer provided on a surface of the second conductive layer away from the insulating layer; an isolation layer covering at least one side surface of surfaces of the current collector provided with the first active material layer or provided with the second active material layer. The utility model discloses an use this mass flow body to replace traditional pole piece mass flow body and diaphragm, can save more spaces for the battery on the one hand to improve the energy density of battery, on the other hand can improve the security performance of battery.
Description
Technical Field
The utility model relates to a battery technology field particularly, relates to a pole piece, electric core and battery.
Background
With the development of science and technology, more and more electronic products enter people's lives, and a large part of electronic products are driven by batteries. Among them, lithium ion batteries are widely used in electronic products in various fields because of their advantages such as long service life and high energy density.
The traditional lithium ion battery mainly comprises a positive plate, a negative plate, a diaphragm, electrolyte and the like, wherein the positive plate comprises a positive current collector and a positive active material layer coated on the surface of the positive current collector, the negative plate comprises a negative current collector and a negative active material layer coated on the surface of the negative current collector, the diaphragm is an important component, and the diaphragm is mainly used for separating the positive plate and the negative plate of the battery to prevent the two electrodes from contacting to cause short circuit of the battery, can be used as a passage for transmitting lithium ions between the positive electrode and the negative electrode, realizes the rapid conduction of the lithium ions between the positive electrode and the negative electrode in the charge-discharge process, and can provide a place for transmitting the lithium ions with the electrolyte.
At present, the electric core structure of lithium ion battery is mostly the range upon range of formula, coiling formula or Z style of calligraphy structure, no matter which kind of structure, and its basic interface structure all is negative pole, diaphragm, the structure setting of positive pole even, regular distribution in turn, and positive and negative pole piece of this kind of structure all contains the pole piece mass flow body, and just must separate with the diaphragm between positive and negative pole piece, and the thickness that causes electric core is thicker, and energy density is less. In addition, when the structure is actually used, certain potential hazards exist in the safety performance of the structure during abnormal use such as needling, extrusion, impact and the like, and the short circuit of the battery is easily caused. With the current demand on the energy density of the lithium ion battery being higher and higher, the demand on the structural design of the product being higher and higher, the thickness of the diaphragm being thinner and thinner, the safety of the battery being lower.
SUMMERY OF THE UTILITY MODEL
The utility model discloses aim at solving the unable problem of compromise of current lithium ion battery's energy density and security performance.
In order to solve the above problem, the first aspect of the present invention provides a pole piece, including:
a current collector comprising a first conductive layer, a second conductive layer, and an insulating layer, the insulating layer being located between the first conductive layer and the second conductive layer;
a first active material layer provided on a surface of the first conductive layer away from the insulating layer;
a second active material layer provided on a surface of the second conductive layer away from the insulating layer;
an isolation layer covering at least one side surface of surfaces of the current collector provided with the first active material layer or provided with the second active material layer.
Further, the isolation layer comprises a first isolation layer and a second isolation layer, the first isolation layer is arranged on the surface, away from the insulation layer, of the first conducting layer and/or the second conducting layer, and the second isolation layer is arranged on the surface, away from the insulation layer, of the first active material layer and/or the second active material layer.
Further, the first isolation layer comprises an insulating filler and a binder.
Further, the second separator layer includes a base film layer, a bonding layer, and a ceramic layer, the base film layer being located between the bonding layer and the ceramic layer, the bonding layer being in contact with the first active material layer and/or the second active material layer, the ceramic layer being provided on a side away from the first active material layer and/or the second active material layer.
Furthermore, the thickness of the insulating layer is 0.5-10 μm, and the thickness of the first conducting layer and/or the second conducting layer is 0.5-10 μm.
Further, the pole piece still includes first utmost point ear and second utmost point ear, first utmost point ear sets up first conducting layer does not set up the surface of first active substance layer one side, the second utmost point ear sets up the second conducting layer does not set up the surface of second active substance layer one side.
Further, the width of the first active material layer and/or the second active material layer is smaller than the width of the current collector.
Further, the width of the first active material layer is not greater than the width of the second active material layer.
A second aspect of the present invention provides an electrical core formed by winding at least one pole piece according to any one of the first aspects, or formed by stacking at least two pole pieces according to any one of the first aspects.
The utility model discloses the third aspect provides a battery, including electric core, electrolyte and casing, the inside formation of casing holds the chamber, electric core with electrolyte is located hold the intracavity, electric core be the second aspect electric core.
The utility model provides a pole piece, through set up polarity opposite first conducting layer and second conducting layer respectively at the both sides surface of mass flow body, and set up first active material layer and second active material layer respectively at the surface that first conducting layer and second conducting layer kept away from the insulating layer, first conducting layer and second conducting layer act as first mass flow body and second mass flow body respectively, and the insulating layer both acts as the carrier of first conducting layer and second conducting layer, can play the effect of separating first active material layer and second active material layer again, prevent that two poles of the earth contact from leading to the battery short circuit; replace traditional pole piece mass flow body and diaphragm with this mass flow body, can save more spaces for the battery on the one hand to improve the energy density of battery, on the other hand can avoid when improper uses such as acupuncture, extrusion, impact, lead to anodal and negative pole contact and the short-circuit current that causes is too big, causes the risk of catching fire or even explosion, and this pole piece also can avoid the battery to lead to the diaphragm shrink to cause the risk of battery short circuit under high temperature.
Drawings
Fig. 1 is a schematic structural diagram of a pole piece in an embodiment of the present invention;
fig. 2 is a schematic structural view of a roll core in the embodiment of the present invention;
description of the reference numerals:
1-current collector; 2-positive electrode active material layer; 3-a negative electrode active material layer; 4-an isolation layer; 5-positive tab; 6-negative pole ear;
11-positive conductive layer; 12-a negative conductive layer; 13-an insulating layer; 41-a first barrier layer; 42-second spacer layer.
Detailed Description
At present, the electric core structure of lithium ion battery is mostly the range upon range of formula, coiling formula or Z style of calligraphy structure, no matter which kind of structure, and its basic interface structure all is negative pole, diaphragm, the structure setting of positive pole even, regular distribution in turn, and positive and negative pole piece of this kind of structure all contains the pole piece mass flow body, and just must separate with the diaphragm between positive and negative pole piece, and the thickness that causes electric core is thicker, and energy density is less. In addition, when the structure is actually used, certain potential hazards exist in the safety performance of the structure during abnormal use such as needling, extrusion, impact and the like, and the short circuit of the battery is easily caused. With the current demand on the energy density of the lithium ion battery being higher and higher, the demand on the structural design of the product being higher and higher, the thickness of the diaphragm being thinner and thinner, and the safety of the battery being reduced.
For solving the technical problem, the utility model provides a pole piece, electric core and battery through replacing traditional pole piece mass flow body and diaphragm with the compound mass flow body, can save more spaces for the battery on the one hand to improve the energy density of battery, on the other hand can improve the security performance of battery.
The technical solutions in the embodiments of the present application will be described in detail and clearly with reference to the accompanying drawings. In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention. Furthermore, in the description of the present invention, "at least one" means one or more unless specifically limited otherwise.
In the description of the embodiments of the present application, the description of the term "some preferred embodiments" means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one preferred embodiment or preferred example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same implementation or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
For further details of the present invention, the present invention will be further described with reference to specific embodiments.
An embodiment of the present application provides a pole piece, including: the current collector comprises a first conductive layer, a second conductive layer and an insulating layer, wherein the insulating layer is positioned between the first conductive layer and the second conductive layer; the first active material layer is arranged on the surface, away from the insulating layer, of the first conductive layer; the second active material layer is arranged on the surface, away from the insulating layer, of the second conductive layer; the isolation layer covers at least one side surface of the current collector on which the first active material layer or the second active material layer is provided.
The first active material layer may be a positive electrode active material layer or a negative electrode active material layer, and the second active material layer may be a negative electrode active material layer or a positive electrode active material layer. The first conductive layer and the second conductive layer have opposite polarities, the first conductive layer may be a positive conductive layer or a negative conductive layer, and correspondingly, the second conductive layer is a negative conductive layer or a positive conductive layer. The embodiment of the present application does not further limit this as long as it can ensure that the first active material layer is provided on the surface of the conductive layer having the same polarity as that of the first active material layer and the second active material layer is provided on the surface of the conductive layer having the same polarity as that of the second active material layer.
The following description will take an example in which the positive electrode conductive layer is a first conductive layer, the negative electrode conductive layer is a second conductive layer, the positive electrode active material layer is a first active material layer, the negative electrode active material layer is a second active material layer, the positive electrode tab is a first electrode tab, and the negative electrode tab is a second electrode tab, and further describes an embodiment of the present application with reference to fig. 1 and 2.
With reference to fig. 1, a first aspect of the present embodiment provides a pole piece, including: a current collector 1, a positive electrode active material layer 2, a negative electrode active material layer 3, and an isolation layer 4, wherein:
the current collector 1 comprises a positive conductive layer 11, a negative conductive layer 12 and an insulating layer 13, wherein the insulating layer 13 is positioned between the positive conductive layer 11 and the negative conductive layer 12;
the positive electrode active material layer 2 is arranged on the surface of the positive electrode conductive layer 11 far away from the insulating layer 13;
the negative electrode active material layer 3 is provided on the surface of the negative electrode conductive layer 12 away from the insulating layer 13;
the separator 4 covers at least one of the surfaces of the current collector 1 on which the positive electrode active material layer 2 or the negative electrode active material layer 3 is provided.
According to the pole piece provided by the embodiment of the application, the positive conducting layer and the negative conducting layer are respectively arranged on the surfaces of the two sides of the current collector, the positive active material layer and the negative active material layer are arranged on the surfaces, far away from the insulating layer, of the positive conducting layer and the negative conducting layer, the positive conducting layer and the negative conducting layer are respectively used as the positive current collector and the negative current collector, the insulating layer is used as a carrier of the positive conducting layer and the negative conducting layer, the effect of separating the positive active material layer and the negative active material layer can be achieved, and the battery short circuit caused by contact of the two poles is prevented; replace traditional pole piece mass flow body and diaphragm with this mass flow body, can save more spaces for the battery on the one hand to improve the energy density of battery, on the other hand can avoid when improper uses such as acupuncture, extrusion, impact, lead to anodal and negative pole contact and the short-circuit current that causes is too big, causes the risk of catching fire or even explosion, and this pole piece also can avoid the battery to lead to the diaphragm shrink to cause the risk of battery short circuit under high temperature.
In addition to the above embodiments, the insulating layer 13 is a non-metal layer, and the insulating layer 13 is a polymer material with good insulating property and excellent mechanical property, and the material of the insulating layer 13 is not further limited in this application, and those skilled in the art can select the material according to actual situations, for example: the insulating layer 13 is one or a combination of several of polyethylene terephthalate, polyethylene glycol, polyethylene, polyvinyl chloride, polybutylene, ethylene vinyl acetate, polyvinylidene fluoride, polytetrafluoroethylene, polycarbonate, polypropylene, polystyrene, polycarbonate, polyformaldehyde, polyhexafluoropropylene, polyurethane, organosilicon, polystyrene, polysulfone, polyamide, polyimide, cellulose, spandex, aramid and derivatives thereof.
In the above embodiment, the positive electrode conductive layer 11 and the negative electrode conductive layer 12 may be formed on both side surfaces of the insulating layer 13 by evaporation, thermal recombination, vacuum sputtering, laser pulse, vacuum deposition, ion plating, and the like.
The positive conductive layer 11 is a metal layer, the negative conductive layer 12 is a metal layer or a non-metal layer, the positive conductive layer 11 and the negative conductive layer 12 are both made of conductive materials, the materials of the positive conductive layer 11 and the negative conductive layer 12 may be the same or different, the materials of the positive conductive layer 11 and the negative conductive layer 12 are not further limited in this application, and those skilled in the art can select the conductive material according to actual situations, for example: the positive conductive layer 11 is one or a combination of more of aluminum, iron, copper, titanium, zirconium, nickel, silver, gold, molybdenum, cobalt, chromium, zinc, magnesium, barium, platinum and tungsten; the negative conductive layer 12 is one or a combination of several of copper, nickel, gold, platinum, carbon black, carbon tubes, silicon carbide, carbon nitride, boronized conductive ceramics, and the like.
In order to reduce the thickness of the current collector 1, further save more space for the battery, and improve the energy density of the battery, on the basis of the above embodiment, the thickness of the insulating layer 13 is 0.5 to 10 μm, the thickness of the positive electrode conductive layer 11 is 0.5 to 10 μm, the thickness of the negative electrode conductive layer 12 is 0.5 to 10 μm, or the thicknesses of the positive electrode conductive layer 11 and the negative electrode conductive layer 12 are both 0.5 to 10 μm. In addition to the above embodiments, as a preferable embodiment, the thickness of the insulating layer 13 is 2 to 5 μm, and the thickness of each of the positive electrode conductive layer 11 and the negative electrode conductive layer 12 is 1 to 3 μm.
In an alternative embodiment, the current collector 1 includes an insulating layer 13, the insulating layer 13 is made of polyethylene terephthalate, an aluminum metal layer is compounded on one side surface of the insulating layer 13 by a vacuum sputtering method to form the positive conductive layer 11, and a copper metal layer is compounded on the other side surface of the insulating layer 13 by a vacuum sputtering method to form the negative conductive layer 12, wherein the thickness of the insulating layer 13 is 6 μm, and the thicknesses of the positive conductive layer 11 and the negative conductive layer 12 are both 1 μm.
In addition to the above embodiments, in order to save more space and further improve the energy density of the battery, the separator 4 covers the surface of the current collector 1 on the side where the positive electrode active material layer 2 is provided or the separator 4 covers the surface of the current collector 1 on the side where the negative electrode active material layer 3 is provided.
In order to reduce the thickness of the cell formed by winding the pole piece, the widths of the positive electrode active material layer 2 and the negative electrode active material layer 3 are both smaller than the width of the current collector 1, that is, the width of the positive electrode active material layer 2 is smaller than the width of the positive electrode conductive layer 11, and the width of the negative electrode active material layer 3 is smaller than the width of the negative electrode conductive layer 12 in the above embodiment.
The widths of the positive electrode active material layer 2 and the negative electrode active material layer 3 may be the same or different, but in order to avoid the problem that the negative electrode active material layer 3 does not receive the position of the lithium ion, the lithium ion is precipitated on the surface of the negative electrode to form a lithium dendrite, and the lithium dendrite pierces the separator 4 to cause a short circuit in the battery and cause thermal runaway, the width of the negative electrode active material layer 3 is not less than the width of the positive electrode active material layer 2, therefore, in order to ensure that the positive electrode active material layer 2 and the negative electrode active material layer 3 are sufficiently separated, the safety of the battery is improved, more space can be saved, and the energy density of the battery is further improved, on the basis of the above embodiment, the separator 4 covers the surface of the current collector 1 on which the negative electrode active material layer 3 is arranged, and the surfaces of the negative electrode active material layer 3 and the negative electrode conducting layer 12 are both covered with the separator 4.
The isolation layer 4 includes first isolation layer 41 and second isolation layer 42, and first isolation layer 41 and second isolation layer set up along the width direction of pole piece in proper order, and insulating layer 13's surface is kept away from at negative pole conducting layer 12 to first isolation layer 41 setting, and insulating layer 13's surface is kept away from at negative pole active material layer 3 to the setting of second isolation layer 42. The first isolation layer 41 and the second isolation layer 42 may be made of the same material or different materials, but in order to reduce the self-discharge performance of the battery cell, and make the second isolation layer 42 and the negative electrode active material layer 3 fit more closely, so as to avoid the risk of short circuit caused by the shrinkage of the isolation layers and influence the safety performance of the battery cell, and on the basis of the above embodiment, the first isolation layer 41 and the second isolation layer 42 are different.
Specifically, the first separator 41 is formed by curing a separator paste applied to the surface of the negative electrode conductive layer 12, wherein the separator paste includes an insulating filler and a binder. The specific types of the insulating filler and the binder are not further limited in this application, and those skilled in the art can select the insulating filler and the binder according to actual conditions as long as the first separation layer 41 formed by curing the insulating filler and the binder is ensured to sufficiently separate the positive electrode active material layer 2 and the negative electrode active material layer 3 and allow lithium ions to pass through, for example: the insulating filler is one or a combination of more of gas-phase silica, alumina, boehmite, zirconia, magnesia, titanium oxide, magnesium hydroxide and organic polymer filler; the binder is styrene butadiene rubber.
The second separator 42 is compounded on the surface of the negative electrode active material layer 3 away from the insulating layer 13. The second separator 42 may be combined with the surface of the negative electrode active material layer 3 by hot pressing, adhesion, or the like, but the second separator 42 is combined with the surface of the negative electrode active material layer 3 away from the insulating layer 13 by hot pressing in order to further reduce the thickness of the pole piece. The second isolation layer 42 includes a base film layer, a bonding layer, and a ceramic layer, in which the base film layer is disposed between the bonding layer and the ceramic layer, the bonding layer is in contact with the negative electrode active material layer, the ceramic layer is disposed on one side of the negative electrode active material layer, and the bonding layer and the negative electrode active material layer are combined together. The materials of the base film layer, the bonding layer and the ceramic layer in the second isolation layer 42 are not further limited in this application, and can be selected by those skilled in the art according to the actual situation.
In order to enable the positive electrode conductive layer 11 and the negative electrode conductive layer 12 to be bonded with the insulating layer 13 more firmly, in some alternative embodiments, an adhesive layer is disposed between the positive electrode conductive layer 11 and the insulating layer 13, and/or an adhesive layer is disposed between the negative electrode conductive layer 12 and the insulating layer 13, wherein the adhesive layer is one or a combination of polyvinylidene fluoride, polytetrafluoroethylene, styrene butadiene rubber, polymethyl methacrylate, polyethylene oxide, polyacrylic acid, polyacrylate, polyamide, polyacrylonitrile, styrene-acrylate, and acrylate.
In addition to the above-described embodiment, the positive electrode active material layer 2 and the negative electrode active material layer 3 are provided in a staggered manner in the width direction of the pole piece so that the thickness of the winding core formed after winding the pole piece can be further reduced.
On the basis of the above embodiment, the pole piece is further provided with a positive tab 5 and a negative tab 6 for transferring charges, the positive tab 5 is disposed on the surface of the positive conductive layer 11 away from the insulating layer 13, that is, the positive tab 5 and the positive active material layer 2 are disposed on the same side, and the positive tab 5 is disposed at the end of the current collector 1 where the positive active material layer 2 is not disposed; the negative electrode tab 6 is disposed on the surface of the negative electrode conductive layer 12 away from the insulating layer 13, that is, the negative electrode tab 6 is disposed on the same side as the negative electrode active material layer 3, and the negative electrode tab 6 is disposed on the end of the current collector 1 where the negative electrode active material layer 3 is not disposed.
In the above embodiment, the positive electrode tab 5 and the negative electrode tab 6 may be formed on the surfaces of the positive electrode conductive layer 11 and the negative electrode conductive layer 12 by means of conductive adhesive bonding, laser welding, ultrasonic welding, roll welding, or the like; in order to avoid short circuit caused by contact between the positive and negative conductive layers due to conduction of welding spots during welding, preferably, the positive tab 5 and the negative tab 6 are bonded on the surfaces of the positive conductive layer 11 and the negative conductive layer 12 by conductive glue, wherein the conductive glue comprises a conductive agent and a binder, the conductive agent comprises one or a combination of more of carbon powder, silver powder, copper powder and gold powder, and the binder is styrene butadiene rubber.
It should be noted that, if the positive tab 5 and the negative tab 6 are welded on the surfaces of the positive conductive layer 11 and the negative conductive layer 12 by using welding methods such as laser welding, ultrasonic welding, roll welding, and the like, the positive conductive layer 11 and the negative conductive layer 12 need to be cleaned off on the surface of the current collector corresponding to the welding area, and only the insulating layer is reserved to prevent short circuit caused by contact between the positive conductive layer and the negative conductive layer due to conduction of welding spots during welding.
The material of the positive tab 5 and the negative tab 6 may be the same or different, and the material of the positive tab 5 and the negative tab 6 is not further limited in this application, and those skilled in the art may select the material according to actual situations, for example: the material of the positive electrode tab 5 and the negative electrode tab 6 is one or a combination of several of aluminum, nickel, copper, iron, titanium and zirconium.
In order to avoid the short circuit phenomenon possibly caused by the burrs on the positive electrode tab 5 and the negative electrode tab 6 and the risk of the short circuit possibly occurring after the positive electrode tab and the negative electrode tab are wound, on the basis of the above embodiment, the surfaces of the positive electrode tab 5 and the negative electrode tab 6, which are far away from the insulating layer, are both provided with insulating adhesive tapes (not shown in the figure).
In the above embodiment, in order to prevent the positive electrode tab 5 and the negative electrode tab 6 from contacting too close to each other to cause short circuit, the positive electrode tab 5 and the negative electrode tab 6 are arranged in a staggered manner in the width direction of the pole piece.
In addition to the structure shown in fig. 1, the positions of the positive electrode active material layer 2 and the negative electrode active material layer 3, the positive electrode conductive layer 11 and the negative electrode conductive layer 12, and the positive electrode tab 5 and the negative electrode tab 6 may be interchanged in the present application as long as the positive electrode active material layer 2 and the positive electrode tab 5 are disposed on the surface of the positive electrode conductive layer 11, and the negative electrode active material layer 3 and the negative electrode tab 6 are disposed on the surface of the negative electrode conductive layer 12.
The second aspect of the present embodiment also provides a battery cell, where the battery cell includes the pole piece described in the first aspect, and at least one pole piece is wound to form the battery cell, or at least two pole pieces are stacked to form the battery cell.
Fig. 2 is a schematic structural diagram of a cell formed by winding. With reference to fig. 2, the positive tab 5 and the negative tab 6 are located inside the battery cell, the positive active material layer 2 and the negative active material layer 3 are respectively disposed on two opposite side surfaces of the pole piece, and the positive active material layer 2 and the negative active material layer 3 are separated by the isolation layer 4 disposed on the surface of the negative active material layer 3.
The third aspect of this embodiment also provides a battery, where the battery includes a battery core, an electrolyte and a casing, a containing cavity is formed inside the casing, the battery core and the electrolyte are located in the containing cavity, the battery core and the electrolyte are encapsulated inside the casing, and the battery core is the battery core as described above.
In order to further explain the present application in detail, the present application will be further explained with reference to specific examples.
Example (b):
forming a current collector: an aluminum metal layer with the thickness of 1 mu m is compounded on one side surface of polyethylene terephthalate with the thickness of 6 mu m as a positive electrode conducting layer by a vacuum sputtering method, and a copper metal layer with the thickness of 1 mu m is compounded on the other side surface of the polyethylene terephthalate as a negative electrode conducting layer by the vacuum sputtering method, so that a current collector is formed.
Providing a positive electrode active material layer: mixing lithium cobaltate (LiCoO) 2 ) Polyvinylidene fluoride (PVDF), conductive carbon black (Super-P) according to 98: 1: 1, adding N-methyl pyrrolidone (NMP) as a solvent, stirring and mixing uniformly to prepare a positive active material, coating the positive active material on the surface of a positive conductive layer, drying at 95 ℃, and rolling to form a positive active material layer.
Providing an anode active material layer: mixing graphite, Styrene Butadiene Rubber (SBR) and sodium carboxymethylcellulose (CMC-Na) according to a mass ratio of 97:2.5:1, adding deionized water as a solvent, stirring and mixing uniformly to prepare a negative active substance, coating the negative active substance on the surface of a negative conductive layer, drying at 105 ℃, and rolling to form a negative active substance layer.
Setting an isolation layer: oil-based nano fumed Silica (SiO) 2 ) Polyvinylidene fluoride (PVDF) according to 80: 20, adding N-methyl pyrrolidone (NMP) as a solvent, stirring and mixing uniformly to prepare an isolation slurry, coating the isolation slurry on the surface of the negative electrode conducting layer without the negative electrode active material layer, wherein the coating thickness is 5 mu m, and drying and rolling to form a first isolation layer; compounding a second isolation layer on the surface of the negative electrode active material layer, wherein the second isolation layer comprises a base film layer, a bonding layer and a ceramic layer, the base film layer is arranged between the bonding layer and the ceramic layer, the bonding layer is in contact with the negative electrode active material layer, the ceramic layer is arranged on one side far away from the negative electrode active material layer, the thickness of the base film layer is 7 micrometers, the thickness of the bonding layer is 2 micrometers, the thickness of the ceramic layer is 3 micrometers, and the bonding layer and the negative electrode active material layer are compounded together through a heating roller at 90 ℃ and under the pressure of 5Kpa in a hot pressing mode.
Setting a positive electrode lug and a negative electrode lug: selecting an aluminum tab with the thickness of 25 micrometers as a positive tab, a nickel tab with the thickness of 20 micrometers as a negative tab, bonding the positive tab to one end of the positive conducting layer without the positive active material layer, bonding the negative tab to one end of the negative conducting layer without the negative active material layer, and compositing an insulating gummed paper with the thickness of 15 micrometers on the surfaces of the positive tab and the negative tab, wherein the insulating gummed paper is made of polyethylene terephthalate to obtain the pole piece.
Forming a battery cell: and winding the pole piece into a battery cell by taking one end provided with the positive pole lug and the negative pole lug as a winding head end.
And (3) preparing a battery: ethylene Carbonate (EC): diethyl carbonate (DEC): ethyl Methyl Carbonate (EMC) in a volume ratio of 1: 1: 1 and 1mol/L of lithium hexafluorophosphate (LiPF) is added 6 ) As a solvent, uniformly mixing to obtain an electrolyte; packaging the battery core by using an aluminum-plastic film, injecting electrolyte into a containing cavity formed in the aluminum-plastic film, aging for a period of time, performing a formation process, cutting off the air bag after the formation process is finished, and performing subsequent processes such as sorting to obtain the battery, wherein the nominal capacity of the battery is 4000mAh, and the maximum charging voltage of the battery is 4000mAhIt was 4.4V.
Comparative example:
the positive electrode active material layer, the negative electrode active material layer, the positive electrode tab and the negative electrode tab in this example are the same as those in the example, except that the electrode tab in this example is a conventional electrode tab, that is, an aluminum foil with a thickness of 10 μm is used as a positive electrode current collector; coating a positive active material layer on the aluminum foil to form a positive plate, taking a copper foil with the thickness of 8 mu m as a negative current collector, and coating a negative active material layer on the copper foil to form a negative plate; a composite membrane formed by a base membrane layer with the thickness of 7 mu m, a bonding layer with the thickness of 2 mu m and a ceramic layer with the thickness of 3 mu m is taken as a diaphragm, the bonding layer faces to the negative plate, and the ceramic layer faces to the positive plate; and (3) superposing and winding the positive plate, the diaphragm and the negative plate to form the battery cell, and encapsulating the battery cell in the aluminum plastic film according to the mode of the embodiment to manufacture the battery.
The performance of the batteries prepared in examples and comparative examples was tested.
And (3) furnace temperature testing: the battery was charged to 4.4V at a current of 1C and then subjected to a constant voltage until the charging was stopped when the current was reduced to 0.05C. And (3) putting the fully charged battery into a furnace temperature test box with circulating air convection, heating the test box to 135 +/-2 ℃ at the speed of 5 +/-2 ℃/min, and keeping the temperature for 30 min. The cells did not fire and did not explode and were considered to pass, 5 per test.
And (3) needle punching test: the battery was charged to 4.4V at a current of 1C and then subjected to a constant voltage until the charge was stopped when the current was reduced to 0.05C. The fully charged cell was placed in a needle punch tester and the geometric center of the cell was pierced at a rate of 50mm/s using a 2mm diameter steel needle and held for 30 min. The cells did not fire and did not explode and were considered to pass, 5 per test.
The test results are shown in table 1.
Table 1 safety test pass rates of examples and comparative examples
As can be seen from table 1, the furnace temperature test result and the needling test result in the embodiment are both in good comparison ratio, which indicates that compared with the conventional battery formed by multiple pole pieces, the battery in the application cancels the conventional diaphragm, and the second isolating layer is directly compounded on the surface of the negative active material layer, so that the risk of short circuit of the positive electrode and the negative electrode caused by thermal shrinkage at high temperature is reduced, the furnace temperature test throughput rate is greatly improved, and when needling occurs, the positive conductive layer and the negative conductive layer are preferentially contacted, the risk of fire or even explosion caused by overlarge short circuit current caused by contact of the two electrodes is greatly reduced, and the safety of needling can be further improved.
Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the present disclosure, and these changes and modifications are intended to fall within the scope of the present disclosure.
Claims (9)
1. A pole piece, comprising:
a current collector comprising a first conductive layer, a second conductive layer, and an insulating layer, the insulating layer being located between the first conductive layer and the second conductive layer;
a first active material layer provided on a surface of the first conductive layer away from the insulating layer;
a second active material layer provided on a surface of the second conductive layer away from the insulating layer;
an isolation layer covering at least one side surface of surfaces of the current collector provided with the first active material layer or provided with the second active material layer.
2. The pole piece of claim 1, wherein the isolation layer comprises a first isolation layer and a second isolation layer, the first isolation layer is disposed on a surface of the first conductive layer and/or the second conductive layer away from the insulating layer, and the second isolation layer is disposed on a surface of the first active material layer and/or the second active material layer away from the insulating layer.
3. The pole piece of claim 2, wherein the second separator layer comprises a base film layer, a bonding layer and a ceramic layer, the base film layer is located between the bonding layer and the ceramic layer, the bonding layer is in contact with the first active material layer and/or the second active material layer, and the ceramic layer is disposed on a side away from the first active material layer and/or the second active material layer.
4. The pole piece of claim 1, wherein the insulating layer has a thickness of 0.5-10 μm, and the first conductive layer and/or the second conductive layer has a thickness of 0.5-10 μm.
5. The pole piece of claim 1, further comprising a first tab disposed on a surface of the first conductive layer on a side where the first active material layer is not disposed and a second tab disposed on a surface of the second conductive layer on a side where the second active material layer is not disposed.
6. The pole piece of claim 1, wherein the width of the first active material layer and/or the second active material layer is less than the width of the current collector.
7. The pole piece of claim 1 or 6, wherein the width of the first active material layer is not greater than the width of the second active material layer.
8. An electrical core formed by winding at least one pole piece according to any one of claims 1 to 7, or by stacking at least two pole pieces according to any one of claims 1 to 7.
9. A battery, characterized by comprising a battery core, electrolyte and a casing, wherein a containing cavity is formed inside the casing, the battery core and the electrolyte are located in the containing cavity, and the battery core is the battery core of claim 8.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123419843.XU CN217507394U (en) | 2021-12-31 | 2021-12-31 | Pole piece, electric core and battery |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123419843.XU CN217507394U (en) | 2021-12-31 | 2021-12-31 | Pole piece, electric core and battery |
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| CN217507394U true CN217507394U (en) | 2022-09-27 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117219894A (en) * | 2023-11-08 | 2023-12-12 | 江苏正力新能电池技术有限公司 | Pole piece, battery and electric equipment |
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2021
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117219894A (en) * | 2023-11-08 | 2023-12-12 | 江苏正力新能电池技术有限公司 | Pole piece, battery and electric equipment |
| CN117219894B (en) * | 2023-11-08 | 2024-03-22 | 江苏正力新能电池技术有限公司 | Pole piece, battery and electric equipment |
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