CN115832202B - Negative electrode plate, lithium ion battery and preparation method of lithium ion battery - Google Patents

Negative electrode plate, lithium ion battery and preparation method of lithium ion battery Download PDF

Info

Publication number
CN115832202B
CN115832202B CN202211655534.9A CN202211655534A CN115832202B CN 115832202 B CN115832202 B CN 115832202B CN 202211655534 A CN202211655534 A CN 202211655534A CN 115832202 B CN115832202 B CN 115832202B
Authority
CN
China
Prior art keywords
negative electrode
active material
heat conducting
lithium ion
ion battery
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202211655534.9A
Other languages
Chinese (zh)
Other versions
CN115832202A (en
Inventor
钟兴国
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cornex New Energy Co ltd
Original Assignee
Cornex New Energy Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cornex New Energy Co ltd filed Critical Cornex New Energy Co ltd
Priority to CN202211655534.9A priority Critical patent/CN115832202B/en
Publication of CN115832202A publication Critical patent/CN115832202A/en
Application granted granted Critical
Publication of CN115832202B publication Critical patent/CN115832202B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50Manufacturing or production processes characterised by the final manufactured product

Landscapes

  • Battery Electrode And Active Subsutance (AREA)

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a negative electrode plate, a lithium ion battery and a preparation method thereof. The invention provides a negative pole piece, which comprises a current collector and a negative pole layer coated on the current collector; the negative electrode layer comprises N heat conducting layers and N+1 active material layers, and a plurality of the heat conducting layers and the active material layers are arranged at intervals along a first direction; n is an integer which is more than or equal to 1 and less than or equal to 10, and the first direction is perpendicular to the length direction of the current collector. According to the invention, the heat conducting layer is added in the negative electrode plate, so that heat generated by the negative electrode during quick charge can be timely transferred to the copper foil, the temperature of the lithium ion battery during charge and discharge is reduced, the safety problem caused by high temperature and the quick decay of the cycle life of the battery are avoided, the cycle life of the battery is further improved, and meanwhile, the risk of thermal safety runaway of the battery is reduced.

Description

Negative electrode plate, lithium ion battery and preparation method of lithium ion battery
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a negative electrode plate, a lithium ion battery and a preparation method thereof.
Background
With the continuous development of consumer electronics and new energy automobiles, lithium ion battery technology is rapidly advanced, substantial progress is currently made in improving specific capacity and cycling performance of batteries through material optimization, and energy density is improved from early 100Wh/Kg to 300Wh/Kg of current high-nickel ternary batteries, so that more and more research interests are focused on reliability and safety of battery layers. Particularly, based on the current demand for fast battery charging capability, thermal safety problems of batteries are receiving increasing attention. In the face of the problem of rapid charging and heating of the current lithium ion battery, the current mainstream solution still distributes heat during charging in a mode of setting water cooling and air cooling from a PACK level, and the occurrence of safety accidents can be avoided, so that the battery PACK efficiency is greatly influenced, and the battery PACK cost is increased; and this way is through the heat dissipation of electric core surface, so it is difficult to in time conduct the heat of electric core inside out, especially the heat that the negative pole inserts lithium ion and produces during fast charge, so can deteriorate the electrochemical performance of battery, especially cycle life.
The existing solution is to add a heat-conducting substance to the negative electrode active material to dissipate heat of the negative electrode sheet, for example, patent document CN113258037a discloses an overcharge-preventing low-temperature rate negative electrode sheet, in which a composite additive slurry (an overcharge-preventing additive, an electric conduction additive, a heat-conducting additive, a dispersing agent and a solvent) and a negative electrode slurry are mixed and then coated on a current collector or layered on the current collector, or a slurry containing a heat-conducting material is coated on an active material layer, but the negative electrode of this structure has low heat dissipation efficiency, the negative electrode material itself has low heat conductivity, a heat-generating body is a heat-generating body during charge and discharge of a battery, the heat-conducting material is mixed and then coated on the current collector or layered on the current collector, the heat-conducting material is dispersed by the negative electrode material, and a continuous heat conductor cannot be formed, and it is difficult to transfer the heat generated by the negative electrode material to a copper foil with high efficiency.
Disclosure of Invention
The invention provides a negative pole piece, a lithium ion battery and a preparation method thereof, and aims to solve the problems that in the prior art, negative pole heat cannot be timely transmitted to the surface of a battery cell through a negative pole current collector, and further the rate performance and the cycle life are attenuated due to high temperature.
In view of the above technical drawbacks, one of the purposes of the present invention is to provide a negative electrode tab, another purpose of the present invention is to provide a method for manufacturing the negative electrode tab, and a third purpose of the present invention is to provide a lithium ion battery assembled by the negative electrode tab, and a fourth purpose of the present invention is to provide a method for manufacturing the lithium ion battery.
In a first aspect, the present invention provides a negative electrode tab comprising a current collector, and a negative electrode layer coated on the current collector;
the negative electrode layer comprises N heat conducting layers and N+1 active material layers, and a plurality of the heat conducting layers and the active material layers are alternately stacked along the width direction of the current collector; the thermally conductive layer includes a thermally conductive agent.
In the above-mentioned negative electrode sheet, the number of N is adjusted according to the actual heat conduction requirement, and as an implementation manner, N is an integer, 1.ltoreq.n.ltoreq.10 (for example, 2, 3, 5, 6, 7, 8, 9).
In the above negative electrode sheet, as a preferred embodiment, each of the active material layers has a width of 3mm to 200mm (for example: 30mm, 60mm, 90mm, 120mm, 150mm, 180 mm);
and/or each of the thermally conductive layers has a width of 0.5mm to 10mm (e.g., 4mm, 6mm, 8 mm).
In the above negative electrode sheet, as a preferred embodiment, each of the active material layers has a thickness of 40 μm to 300 μm (for example, 80 μm, 120 μm, 200 μm, 240 μm, 280 μm);
and/or the thickness of each heat conducting layer is the same as the thickness of the active material layer or 1-20 μm lower than the thickness of the active material layer.
In the above-mentioned negative electrode sheet, as a preferred embodiment, the heat conductive agent in the heat conductive layer accounts for 0.5% -10% (such as 1%, 2%, 3%, 5%, 7%, 9%) of the mass of the negative electrode active material in the active material layer.
In the above negative electrode tab, as a preferred embodiment, the heat conductive layer includes a heat conductive agent, a first conductive agent, and a first binder;
the mass ratio of the heat conducting agent to the first conductive agent to the first binder is (50-90): (5-50): (3-30), and the sum of mass ratios is equal to 100;
the heat conductive agent comprises one or more of boron nitride, magnesium nitride, aluminum nitride, titanium nitride, zirconium nitride, zinc oxide, aluminum oxide and magnesium oxide.
In the above negative electrode tab, as a preferred embodiment, the active material layer includes a negative electrode active material, a second conductive agent, and a second binder;
the mass ratio of the anode active material to the second conductive agent to the second binder is (90-98): (0.5-5): (0.5-5), and the sum of mass ratios is equal to 100.
In the above negative electrode sheet, the negative electrode active material includes, but is not limited to, one or more of graphite, hard carbon, mesophase microspheres, silicon-based materials, tin-based materials, and graphene.
In the above negative electrode sheet, the first conductive agent and the second conductive agent are not limited, and may be conductive agents commonly used in a manufacturing process of the negative electrode sheet, and as a preferred embodiment, the first conductive agent and the second conductive agent respectively include one or more of conductive carbon black, acetylene black, ketjen black, conductive graphite, conductive carbon fiber, carbon nanotube, graphene, metal powder, or carbon fiber, where the first conductive agent and the second conductive agent may be the same or different;
in the above negative electrode sheet, the first binder and the second binder are not limited, and may be binders commonly used in a manufacturing process of the negative electrode sheet, where the first binder and the second binder respectively include one or more of styrene-butadiene latex (SBR), carboxymethyl cellulose (CMC), polyacrylic acid (PAA), lithium polyacrylate (PAA-Li), sodium polyacrylate (PAA-Na), polyvinyl alcohol (PVA), polyvinylidene fluoride (PVDF), and sodium carboxymethyl cellulose, and the first binder and the second binder may be the same or different.
In a second aspect, the invention also provides a preparation method of the negative electrode plate, which comprises the following steps,
preparing heat conduction slurry: dissolving a heat conducting agent, a first conductive agent and a first binder in deionized water or an alcohol solvent according to a proportion, and uniformly stirring to obtain heat conducting slurry;
preparing active material slurry: dissolving a negative electrode active material, a second conductive agent and a second binder in deionized water according to a proportion, and uniformly stirring to obtain active material slurry;
preparing a negative electrode plate: and coating the heat-conducting slurry and the active material slurry on a current collector according to a designed negative electrode layer structure, and drying, cold pressing and cutting to obtain a negative electrode plate.
In the above preparation method, as a preferred embodiment, the coating mode adopts extrusion coating; the coating equipment is a conventional extrusion coater.
The coating is single-sided coating or double-sided coating;
the alcohol solvent can be methanol solution, ethanol solution, isopropanol solution or n-butanol solution;
the mass fraction of the methanol solution, ethanol solution, isopropanol solution, and n-butanol solution is preferably 50-100% (e.g., 60%, 70%, 80%, 90%).
The drying, cold pressing and cutting are all conventional methods for preparing the negative electrode plate in the field.
In a third aspect, the invention also provides a lithium ion battery, which comprises a positive electrode plate, a diaphragm, electrolyte and the negative electrode plate.
The lithium ion battery also comprises a shell.
In a fourth aspect, the invention also provides a preparation method of the lithium ion battery, which comprises the following steps,
and sequentially laminating the positive electrode plate, the diaphragm and the negative electrode plate, winding the positive electrode plate, the diaphragm and the negative electrode plate into a battery core, placing the battery core in an aluminum plastic film, drying the battery core, injecting electrolyte, and then carrying out vacuum packaging, standing, formation and shaping to obtain the lithium ion battery.
In the invention, drying, vacuum packaging, standing, formation and shaping are all conventional methods for preparing lithium ion batteries in the field.
Compared with the prior art, the invention has at least one of the following beneficial effects:
1. the invention provides a negative pole piece, which comprises a current collector and a negative pole layer coated on the current collector; the negative electrode layer comprises N heat conducting layers and N+1 active material layers, and a plurality of the heat conducting layers and the active material layers are arranged at intervals along a first direction; and N is an integer which is more than or equal to 1 and less than or equal to 10, wherein the first direction is perpendicular to the length direction of the current collector (a plurality of heat conducting layers and active material layers are alternately laminated along the width direction of the current collector). According to the invention, the heat conducting layer is added in the negative electrode plate, so that heat generated by the negative electrode during quick charge can be timely transferred to the copper foil, the temperature of the lithium ion battery during charge and discharge is reduced, the safety problem caused by high temperature and the quick decay of the cycle life of the battery are avoided, the cycle life of the battery is further improved, and meanwhile, the risk of thermal safety runaway of the battery is reduced.
2. The conductive agent and the heat conductive agent in the heat conductive layer can ensure that the heat conductive layer has better liquid retaining capacity, stores more electrolyte, can provide more lithium ion channels for the negative electrode, is parallel to the lithium ion rapid conduction surface of the negative electrode graphite, can accelerate the conduction of lithium ions in the negative electrode active material, and improves the overall multiplying power capacity of the battery cell.
3. According to the invention, the heat generated during the fast charging of the battery cell is reduced on the pole piece level, the partial cooling structure of the PACK level is reduced, the space utilization rate and the energy density of the battery system are improved, and the cost is reduced.
Drawings
FIG. 1 is a widthwise cross-sectional view of a positive electrode sheet of the present invention;
fig. 2 is a top view of the positive electrode tab of the present invention.
Description of the drawings: 1-current collector, 2-heat conducting layer, 3-active material layer.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The examples of the present invention are implemented on the premise of the technical scheme of the present invention, and detailed implementation modes and processes are given, but the protection scope of the present invention is not limited to the following examples, in which the process parameters of specific conditions are not noted, and generally according to conventional conditions.
The endpoints of the ranges and any values disclosed in the present invention are not limited to the precise range or value, and the range or value should be understood to include values close to the range or value. For numerical ranges, one or more new numerical ranges may be obtained in combination with each other between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point values, and are to be considered as specifically disclosed in the present invention.
In the present invention, all values relating to the amounts of the components are "parts by weight" throughout unless specified and/or indicated otherwise. The process parameters for the specific conditions not noted in the examples below are generally as usual.
The following examples are given to illustrate the present invention, but are not intended to limit the scope of the present invention. The examples provided below may be used as a basis for further modifications and applications by those of ordinary skill in the art and are not intended to limit the scope of the invention in any way.
The positive electrode sheet, separator and electrolyte in the following examples and comparative examples were prepared by the following methods:
the preparation method of the positive electrode plate comprises the following steps:
positive electrode active material-LiNi 0.8 Co 0.1 Mn 0.1 O 2 Conductive carbon black Super-P and binder PVDF according to the weight ratio of 97.6:1.3:1.1, fully stirring in an N-methyl pyrrolidone (NMP) solvent system by a vacuum stirrer to obtain anode slurry; and coating the positive electrode slurry on two surfaces of a 12 mu mAl foil substrate, and sequentially drying, cold pressing, slitting and cutting to obtain the positive electrode plate.
The preparation method of the diaphragm comprises the following steps:
the separator substrate was Polyethylene (PE) 8 μm thick, each of the two sides of the separator substrate was coated with a 2 μm alumina ceramic layer, and finally each of the two sides coated with the ceramic layer was coated with 2.5mg of binder polyvinylidene fluoride (PVDF), and dried to obtain a separator.
The preparation method of the electrolyte comprises the following steps:
ethylene Carbonate (EC), methyl ethyl carbonate (EMC) and dimethyl carbonate (DMC) are mixed according to a volume ratio of 3:3:4 mixing to obtain an organic solvent, followed by a sufficiently dry LiPF 6 Dissolving in the mixed organic solvent to prepare the electrolyte with the concentration of 1 mol/L.
Example 1
The embodiment provides a preparation method of a negative electrode plate, which comprises the following steps:
graphite, super-P conductive agent, styrene-butadiene latex and sodium carboxymethyl cellulose are mixed according to the mass ratio of 96.5:1:1.2:1.3, dissolving the mixture in deionized water, and fully stirring and uniformly mixing the mixture to obtain active material slurry;
aluminum nitride, conductive carbon black, styrene-butadiene latex and sodium carboxymethyl cellulose are mixed according to the mass ratio of 80:15:3:2, dissolving the mixture in ethanol solution (the mass fraction is 95 percent), and fully stirring and uniformly mixing to obtain heat-conducting slurry;
and (3) coating the active material slurry and the heat-conducting slurry on the surface of the negative electrode current collector 1 (6 mu m copper foil) through an extrusion coater, and sequentially drying, cold pressing and cutting to obtain the negative electrode plate.
In the negative electrode sheet prepared in this example, each active material layer 3 had a thickness of 160 μm and a width of 15mm, and each heat conductive layer 2 had a thickness of 160 μm and a width of 2mm. The negative electrode plate comprises 3 heat conducting layers and 4 active material layers. In the negative electrode plate, the mass ratio of aluminum nitride to graphite is 3%.
The embodiment also provides a preparation method of the lithium ion battery, which comprises the following steps:
sequentially stacking the positive pole piece, the isolating film and the negative pole piece, enabling the isolating film to be positioned between the positive pole piece and the negative pole piece to play a role of isolation, and then winding to obtain a bare cell; and welding the qualified bare cell on the top cover through the electrode lug, placing the bare cell in an outer packaging shell, drying, injecting electrolyte, and performing procedures such as vacuum packaging, standing, formation, shaping and the like to obtain the lithium ion battery with the capacity of about 5000mAh.
Example 2
The embodiment provides a preparation method of a negative electrode plate, which comprises the following steps:
the difference between this example and example 1 is that 95% by weight of graphite and 5% by weight of silica (S0221-Rankine) are used as the negative electrode active material, and the rest is the same as example 1.
In the negative electrode sheet prepared in this example, each active material layer had a thickness of 140 μm and a width of 15mm, and each heat conductive layer had a thickness of 140 μm and a width of 2mm. The negative electrode plate comprises 3 heat conducting layers and 4 active material layers.
The embodiment also provides a preparation method of the lithium ion battery, which comprises the following steps:
sequentially stacking the positive pole piece, the isolating film and the negative pole piece, enabling the isolating film to be positioned between the positive pole piece and the negative pole piece to play a role of isolation, and then winding to obtain a bare cell; and welding the qualified bare cell on the top cover through the electrode lug, placing the bare cell in an outer packaging shell, drying, injecting electrolyte, and performing procedures such as vacuum packaging, standing, formation, shaping and the like to obtain the lithium ion battery with the capacity of about 5000mAh.
Example 3
The embodiment provides a preparation method of a negative electrode plate, which comprises the following steps:
the difference between the preparation method of this example and that of example 1 is that titanium nitride is used as the heat conductive agent, and the remainder is the same as that of example 1.
In the negative electrode sheet prepared in this example, each active material layer 3 had a thickness of 160 μm and a width of 15mm, and each heat conductive layer 2 had a thickness of 160 μm and a width of 2mm. The negative electrode plate comprises 3 heat conducting layers and 4 active material layers.
The embodiment also provides a preparation method of the lithium ion battery, which comprises the following steps:
sequentially stacking the positive pole piece, the isolating film and the negative pole piece, enabling the isolating film to be positioned between the positive pole piece and the negative pole piece to play a role of isolation, and then winding to obtain a bare cell; and welding the qualified bare cell on the top cover through the electrode lug, placing the bare cell in an outer packaging shell, drying, injecting electrolyte, and performing procedures such as vacuum packaging, standing, formation, shaping and the like to obtain the lithium ion battery with the capacity of about 5000mAh.
Example 4
The difference between this example and example 1 is that boron nitride is used as the heat conductive agent, and the remainder is the same as in example 1.
In the negative electrode sheet prepared in this example, each active material layer 3 had a thickness of 160 μm and a width of 15mm, and each heat conductive layer 2 had a thickness of 160 μm and a width of 2mm. The negative electrode plate comprises 3 heat conducting layers and 4 active material layers.
The embodiment also provides a preparation method of the lithium ion battery, which comprises the following steps:
sequentially stacking the positive pole piece, the isolating film and the negative pole piece, enabling the isolating film to be positioned between the positive pole piece and the negative pole piece to play a role of isolation, and then winding to obtain a bare cell; and welding the qualified bare cell on the top cover through the electrode lug, placing the bare cell in an outer packaging shell, drying, injecting electrolyte, and performing procedures such as vacuum packaging, standing, formation, shaping and the like to obtain the lithium ion battery with the capacity of about 5000mAh.
Example 5
The difference between the preparation method of this example and that of example 1 is that the preparation of the heat conductive paste of this example is: aluminum nitride, conductive carbon black, graphene, styrene-butadiene latex and sodium carboxymethyl cellulose are mixed according to the mass ratio of 80:14:3:1.6:1.4 in deionized water, and fully stirring and uniformly mixing to obtain the heat-conducting slurry, wherein the rest is the same as in the example 1.
In the negative electrode sheet prepared in this example, each active material layer 3 had a thickness of 160 μm and a width of 15mm, and each heat conductive layer 2 had a thickness of 160 μm and a width of 2mm. The negative electrode plate comprises 3 heat conducting layers and 4 active material layers.
The embodiment also provides a preparation method of the lithium ion battery, which comprises the following steps:
sequentially stacking the positive pole piece, the isolating film and the negative pole piece, enabling the isolating film to be positioned between the positive pole piece and the negative pole piece to play a role of isolation, and then winding to obtain a bare cell; and welding the qualified bare cell on the top cover through the electrode lug, placing the bare cell in an outer packaging shell, drying, injecting electrolyte, and performing procedures such as vacuum packaging, standing, formation, shaping and the like to obtain the lithium ion battery with the capacity of about 5000mAh.
Comparative example 1
The comparative example provides a preparation method of a negative electrode plate, which comprises the following steps:
graphite, a conductive agent, styrene-butadiene latex and sodium carboxymethyl cellulose are mixed according to the mass ratio of 96.5:1:1.2:1.3, dissolving the mixture in ethanol solution (the mass fraction is 95 percent), and fully stirring and uniformly mixing the mixture to obtain active material slurry;
and (3) coating the active material slurry on the surface of a negative current collector (6 mu m copper foil), and sequentially drying, cold pressing and cutting to obtain a negative electrode plate.
In the negative electrode sheet prepared in this comparative example, the thickness of the active material layer was 160 μm and the width was 66mm.
The comparative example also provides a method for preparing a lithium ion battery, comprising the following steps,
sequentially stacking the positive pole piece, the isolating film and the negative pole piece, enabling the isolating film to be positioned between the positive pole piece and the negative pole piece to play a role of isolation, and then winding to obtain a bare cell; and welding the qualified bare cell on the top cover through the electrode lug, placing the bare cell in an outer packaging shell, drying, injecting electrolyte, and performing procedures such as vacuum packaging, standing, formation, shaping and the like to obtain the lithium ion battery with the capacity of about 5000mAh.
Comparative example 2
The comparative example provides a preparation method of a negative electrode plate, which comprises the following steps:
the difference between the present comparative example and comparative example 1 is that graphite +5% silicon carbon is used as the negative electrode active material, and the remainder is the same as comparative example 1.
In the negative electrode sheet prepared in this comparative example, the thickness of the active material layer was 140 μm and the width was 66mm.
The comparative example also provides a method for preparing a lithium ion battery, comprising the following steps,
sequentially stacking the positive pole piece, the isolating film and the negative pole piece, enabling the isolating film to be positioned between the positive pole piece and the negative pole piece to play a role of isolation, and then winding to obtain a bare cell; and welding the qualified bare cell on the top cover through the electrode lug, placing the bare cell in an outer packaging shell, drying, injecting electrolyte, and performing procedures such as vacuum packaging, standing, formation, shaping and the like to obtain the lithium ion battery with the capacity of about 5000mAh.
Comparative example 3
The comparative example provides a preparation method of a negative electrode plate, which comprises the following steps:
the comparative example was different from example 1 in that after the active material slurry and the heat conductive slurry were prepared, the active material slurry and the heat conductive slurry were uniformly mixed and then coated on the negative electrode current collector, and the remaining steps were the same as example 1.
The comparative example also provides a method for preparing a lithium ion battery, comprising the following steps,
sequentially stacking the positive pole piece, the isolating film and the negative pole piece, enabling the isolating film to be positioned between the positive pole piece and the negative pole piece to play a role of isolation, and then winding to obtain a bare cell; and welding the qualified bare cell on the top cover through the electrode lug, placing the bare cell in an outer packaging shell, drying, injecting electrolyte, and performing procedures such as vacuum packaging, standing, formation, shaping and the like to obtain the lithium ion battery with the capacity of about 5000mAh.
Test case
The lithium ion batteries prepared in examples 1 to 5 and comparative examples 1 to 3 were tested for charging rate, battery surface temperature rise condition and cycle life.
The method for testing the charging multiplying power comprises the following steps: 2C capacity: the battery was discharged at 1C to 2.75V at 25 ℃, left to stand for 1 hour, charged at 2C to 4.2V, left to stand for 1 hour, and finally discharged at 2C to 2.75V and the 2C discharge capacity was measured.
The 2C charge rate is the 2C capacity divided by the 1C capacity.
3C capacity: the battery was discharged at 1C to 2.75V at 25 ℃, left to stand for 1 hour, charged at 3C to 4.2V, left to stand for 1 hour, and finally discharged at 3C to 2.75V and the 3C discharge capacity was measured.
The 3C charging rate is 3C capacity divided by 1C capacity;
the 500 cycle life test method comprises the following steps: the cell was discharged at 1C to 2.75V at 25 ℃, left to stand for 1 hour, charged at 1C to 4.2V, left to stand for 1 hour, finally discharged at 1C to 2.75V and the 1C discharge capacity (i.e., capacity at the first cycle) was measured, and the capacity at the first cycle was divided by the capacity after 500 cycles.
The specific test results are shown in the following table:
from the test summary results of the table, when the heat conducting layer is added in the negative electrode plate according to the mode of the invention, the temperature rise of the lithium ion battery during charge and discharge can be reduced, the rate retention rate of the lithium ion battery can be improved, and the cycle life of the battery can be further improved. In addition, as can be seen from the comparison of the data between example 1 and comparative example 3, the negative electrode sheet prepared by coating the heat conductive agent and the active slurry on the negative electrode current collector in a mixed manner was inferior to the negative electrode sheet in which the heat conductive layer was added between the active material layers in the manner of the present invention in terms of the rate retention, the temperature rise, and the 500-cycle performance.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the particular embodiments disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

Claims (9)

1. The negative electrode plate is characterized by comprising a current collector and a negative electrode layer coated on the current collector;
the negative electrode layer comprises N heat conducting layers and N+1 active material layers, and a plurality of the heat conducting layers and the active material layers are alternately stacked along the width direction of the current collector; the heat conducting layer comprises a heat conducting agent;
the heat conducting agent in the heat conducting layer accounts for 0.5-10% of the mass percentage of the negative electrode active material in the active material layer;
the heat conducting layer comprises a heat conducting agent, a first electric conducting agent and a first binder;
the heat conducting agent comprises one or more of boron nitride, magnesium nitride, aluminum nitride, titanium nitride and zirconium nitride;
n is an integer which is more than or equal to 3 and less than or equal to 10.
2. The negative electrode sheet according to claim 1, wherein the width of each of the active material layers is 3mm to 200mm;
and/or, the width of each heat conducting layer is 0.5mm-10mm.
3. The negative electrode sheet according to claim 1, wherein the thickness of each of the active material layers is 40 μm to 300 μm;
and/or the thickness of each heat conducting layer is the same as the thickness of the active material layer or 1-20 μm lower than the thickness of the active material layer.
4. The negative electrode tab of claim 1, wherein,
the mass ratio of the heat conducting agent to the first conductive agent to the first binder is (50-90): (5-50): (3-30), and the sum of mass ratios is equal to 100.
5. The negative electrode tab of claim 1, wherein the active material layer comprises a negative electrode active material, a second conductive agent, and a second binder;
the mass ratio of the anode active material to the second conductive agent to the second binder is (90-98): (0.5-5): (0.5-5), and the sum of mass ratios is equal to 100.
6. A method for producing a negative electrode sheet according to any one of claims 1 to 5, comprising the steps of,
preparing heat conduction slurry: dissolving a heat conducting agent, a first conductive agent and a first binder in deionized water or an alcohol solvent according to a proportion, and uniformly stirring to obtain heat conducting slurry;
preparing active material slurry: dissolving a negative electrode active material, a second conductive agent and a second binder in deionized water according to a proportion, and uniformly stirring to obtain active material slurry;
preparing a negative electrode plate: and coating the heat-conducting slurry and the active material slurry on a current collector according to a designed negative electrode layer structure, and drying, cold pressing and cutting to obtain a negative electrode plate.
7. The method for preparing a negative electrode sheet according to claim 6, wherein the coating mode is extrusion coating;
the coating is single-sided coating or double-sided coating;
the alcohol solvent is one or more of methanol solution, ethanol solution, isopropanol solution and n-butanol solution.
8. A lithium ion battery comprising a positive electrode sheet, a separator, an electrolyte, and the negative electrode sheet of any one of claims 1-5 or prepared by the method of claim 6 or 7.
9. A method for preparing a lithium ion battery according to claim 8, comprising the steps of,
laminating a positive electrode plate, a diaphragm, the negative electrode plate prepared by any one of claims 1-5 or the negative electrode plate prepared by the method of claim 6 or 7 in sequence, winding into a battery core, placing into an aluminum plastic film, drying, injecting electrolyte, and then vacuum packaging, standing, forming and shaping to obtain the lithium ion battery.
CN202211655534.9A 2022-12-21 2022-12-21 Negative electrode plate, lithium ion battery and preparation method of lithium ion battery Active CN115832202B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202211655534.9A CN115832202B (en) 2022-12-21 2022-12-21 Negative electrode plate, lithium ion battery and preparation method of lithium ion battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211655534.9A CN115832202B (en) 2022-12-21 2022-12-21 Negative electrode plate, lithium ion battery and preparation method of lithium ion battery

Publications (2)

Publication Number Publication Date
CN115832202A CN115832202A (en) 2023-03-21
CN115832202B true CN115832202B (en) 2023-09-29

Family

ID=85517640

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202211655534.9A Active CN115832202B (en) 2022-12-21 2022-12-21 Negative electrode plate, lithium ion battery and preparation method of lithium ion battery

Country Status (1)

Country Link
CN (1) CN115832202B (en)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009043515A (en) * 2007-08-08 2009-02-26 Hitachi Maxell Ltd Electrode for battery, method of manufacturing the same, and battery having electrode for battery
CN113036075A (en) * 2021-02-26 2021-06-25 珠海冠宇电池股份有限公司 Pole piece and battery cell
CN113258037A (en) * 2021-05-28 2021-08-13 陕西煤业化工技术研究院有限责任公司 Overcharge-prevention low-temperature-rate negative pole piece, manufacturing method thereof and lithium ion battery based on overcharge-prevention low-temperature-rate negative pole piece
CN114203962A (en) * 2021-12-13 2022-03-18 珠海冠宇动力电池有限公司 Pole piece, battery core and battery
CN114207872A (en) * 2019-08-09 2022-03-18 株式会社半导体能源研究所 Negative electrode, secondary battery, and solid-state secondary battery
CN216849989U (en) * 2021-11-10 2022-06-28 宁德时代新能源科技股份有限公司 Laminated cell, single battery, battery and power utilization device
WO2022181489A1 (en) * 2021-02-25 2022-09-01 三洋電機株式会社 Negative electrode for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery
CN217768423U (en) * 2022-02-10 2022-11-08 宁德时代新能源科技股份有限公司 Negative electrode plate, secondary battery, battery module, battery pack and electric device

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009043515A (en) * 2007-08-08 2009-02-26 Hitachi Maxell Ltd Electrode for battery, method of manufacturing the same, and battery having electrode for battery
CN114207872A (en) * 2019-08-09 2022-03-18 株式会社半导体能源研究所 Negative electrode, secondary battery, and solid-state secondary battery
WO2022181489A1 (en) * 2021-02-25 2022-09-01 三洋電機株式会社 Negative electrode for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery
CN113036075A (en) * 2021-02-26 2021-06-25 珠海冠宇电池股份有限公司 Pole piece and battery cell
CN113258037A (en) * 2021-05-28 2021-08-13 陕西煤业化工技术研究院有限责任公司 Overcharge-prevention low-temperature-rate negative pole piece, manufacturing method thereof and lithium ion battery based on overcharge-prevention low-temperature-rate negative pole piece
CN216849989U (en) * 2021-11-10 2022-06-28 宁德时代新能源科技股份有限公司 Laminated cell, single battery, battery and power utilization device
CN114203962A (en) * 2021-12-13 2022-03-18 珠海冠宇动力电池有限公司 Pole piece, battery core and battery
CN217768423U (en) * 2022-02-10 2022-11-08 宁德时代新能源科技股份有限公司 Negative electrode plate, secondary battery, battery module, battery pack and electric device

Also Published As

Publication number Publication date
CN115832202A (en) 2023-03-21

Similar Documents

Publication Publication Date Title
CN105958008B (en) A kind of lithium ion battery anode composite piece, preparation method and lithium ion battery
WO2021057483A1 (en) Secondary battery, and battery module, battery pack, and device comprising the secondary battery
CN105810899A (en) Lithium ion battery
WO2021109811A1 (en) Secondary battery, battery module having same, battery pack, and device
WO2022041259A1 (en) Secondary battery and preparation method therefor, and battery module, battery pack and device comprising secondary battery
CN113066954B (en) Negative plate and application thereof
CN112018326A (en) Negative plate and lithium ion battery comprising same
JP7446459B2 (en) Separators, their manufacturing methods, and related secondary batteries, battery modules, battery packs, and devices
CN111048749A (en) Negative pole piece, lithium ion battery and manufacturing method thereof
CN112670450A (en) Negative pole piece for solid-state battery and preparation method and application thereof
WO2023230859A1 (en) Secondary battery and preparation method therefor, battery module, battery pack, and electric device
CN115939308A (en) Lithium-supplement positive pole piece, preparation method thereof and lithium ion battery
JP2023504478A (en) Secondary battery and device equipped with the secondary battery
CN113113603A (en) Lithium ion battery electrode plate, preparation method thereof and lithium ion battery
WO2023077516A1 (en) Negative pole piece and preparation method therefor, secondary battery, battery module, battery pack, and electric apparatus
CN114204038A (en) Current collector and application thereof
CN117637988A (en) Negative electrode plate of high-energy-density battery, preparation method of negative electrode plate, battery and power utilization device
CN113140699A (en) Composite negative plate and lithium ion battery comprising same
CN108987705B (en) Electrode material composition, lithium ion battery positive plate and lithium ion battery
CN116190556A (en) Negative electrode plate, battery cell, lithium ion battery and preparation method of lithium ion battery
CN115832202B (en) Negative electrode plate, lithium ion battery and preparation method of lithium ion battery
CN115036458B (en) Lithium ion battery
CN114171849A (en) Core-shell structure composite diaphragm and preparation method thereof
WO2023202289A1 (en) Negative electrode plate and preparation method therefor, secondary battery, battery module, battery pack, and electric device
CN115064823B (en) Battery cell

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant