CN111864192A - Lithium battery positive electrode slurry, lithium battery positive electrode plate and lithium battery - Google Patents
Lithium battery positive electrode slurry, lithium battery positive electrode plate and lithium battery Download PDFInfo
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- CN111864192A CN111864192A CN201910348439.6A CN201910348439A CN111864192A CN 111864192 A CN111864192 A CN 111864192A CN 201910348439 A CN201910348439 A CN 201910348439A CN 111864192 A CN111864192 A CN 111864192A
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- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
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- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
- H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
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- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/028—Positive electrodes
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- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention provides a lithium battery positive electrode slurry which is characterized by comprising a positive electrode active substance and an additive, wherein the additive is a polyisocyanate compound, and the polyisocyanate compound contains a branched chain with hydroxyl. The positive electrode slurry contains a polyisocyanate compound with hydroxyl, and the hydroxyl can be subjected to a polymerization reaction with a carbonate electrolyte at a high temperature to generate a jelly to cover the surface of the positive electrode, so that an internal ion passage of the lithium ion battery can be blocked, and the safety problem of the battery caused by the short circuit of the positive electrode and the negative electrode at the high temperature is avoided.
Description
Technical Field
The invention relates to the technical field of lithium batteries, in particular to a lithium battery positive electrode slurry, a lithium battery positive electrode plate and a lithium battery.
Background
Compared with traditional secondary batteries such as lead-acid batteries, nickel-metal hydride batteries and the like, the lithium battery has the advantages of high energy density, high output voltage, low self-discharge, no memory effect, environmental friendliness and the like, so that the lithium battery is widely applied and researched in different fields. With the development of new energy automobiles, the performance of power batteries also becomes a focus of attention, and higher requirements are put forward on the energy density, safety performance, cycle performance and the like of the power batteries. The energy density of the power battery influences the endurance mileage of the new energy automobile, and therefore, the battery with high energy density is undoubtedly a research hotspot. However, the increase of the energy density also faces a serious safety problem. For example, during the use of the battery, the internal temperature of the battery is increased due to factors such as overcharge, puncture, overheating, extrusion, collision, vibration and the like, so that thermal runaway of the battery is caused, and the safety problem of the battery is brought. Generally, power batteries are all provided with safety valves, and when internal pressure is too high, the safety valves are opened due to the fact that the internal pressure is too high, pressure inside the batteries is released, and safety of the batteries is improved. However, in the actual use process, a situation that the inside of the battery has undergone violent reaction and the safety valve is not opened may often occur; or a violent reaction inside the battery, the safety valve cannot be opened at the first time, causing a delay in the start of the safety measures, thereby adversely affecting the battery.
In order to prevent the thermal runaway of the battery caused by the overhigh internal temperature of the battery, in the prior art, a high-flash-point solvent such as one or more of a fluoro solvent, a sulfone solvent and cyclic carboxylic ester is added, and flame-retardant additives such as trimethyl phosphate and triphenyl phosphate are added, so that the safety performance of the battery is improved from the inside of the battery. However, for high-flash-point solvent fluoro-solvents, sulfone solvents, cyclic carboxylic esters and phosphoric acid flame-retardant additives, film formation on the surface of the negative electrode is influenced, and the cycle performance of the battery is further influenced; phosphoric acid-based flame retardant additives can peel off the graphite negative electrode and react with the lithium-intercalated graphite, thereby affecting the battery performance.
Disclosure of Invention
In order to solve the problem of battery safety caused by battery thermal runaway caused by abuse conditions such as overcharge, puncture, overheating and the like of a battery in the prior art, the invention provides lithium battery positive electrode slurry, a lithium battery positive electrode sheet and a lithium battery, and the cycle performance and the safety performance of the battery under the high-temperature condition are greatly improved.
In order to achieve the above object, in a first aspect, the present invention provides a lithium battery positive electrode slurry, including a positive electrode active material and an additive, where the additive is a polyisocyanate compound, and the polyisocyanate compound includes a branched chain having a hydroxyl group.
Compared with the prior art, the positive pole slurry provided by the invention contains a polyisocyanate compound, the compound has a branched chain containing hydroxyl, and the hydroxyl can be subjected to a polymerization reaction with a carbonate electrolyte at a high temperature to generate a jelly to cover the surface of a positive pole, so that an internal ion passage of a lithium ion battery can be blocked, and the safety problem of the battery caused by short circuit of the positive pole and the negative pole at the high temperature is avoided.
In a second aspect, the invention provides a lithium battery positive plate, which comprises a positive current collector and positive slurry coated on the positive current collector, wherein the positive slurry is the lithium battery positive slurry.
Compared with the prior art, the positive plate provided by the invention contains the additive of the polyisocyanate compound, the additive is provided with the branched chain containing the hydroxyl, and the hydroxyl can react with the carbonate electrolyte to generate jelly at high temperature, and the jelly can cover the surface of the positive plate, so that the contact between the positive electrode and the electrolyte and between the positive electrode and the negative electrode can be isolated, the side reaction between the positive electrode and the electrolyte can be avoided, and the battery safety problem caused by the contraction of a diaphragm and the short circuit of the contact between the positive electrode and the negative electrode can be avoided. The lithium battery assembled by the lithium battery positive plate provided by the invention has good high-temperature cycle performance, and can avoid the battery safety problem caused by thermal runaway.
In a third aspect, the present invention provides a lithium battery, including a positive plate, a negative plate, a diaphragm and an electrolyte, wherein the positive plate is the above-mentioned positive plate of the lithium battery.
Compared with the prior art, the lithium battery provided by the invention has the following beneficial effects: because the polyisocyanate compound exists in the positive plate and the compound contains hydroxyl, the compound can react with the carbonate electrolyte at high temperature to generate jelly to cover the surface of the positive plate, thereby isolating the contact of the positive plate and the negative plate, increasing the internal resistance of the battery, leading the heat production to be rapidly reduced even if the short circuit of the positive plate and the negative plate caused by the melting of a diaphragm and the like occurs, and radically solving the problem of thermal runaway of the battery.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a graph showing the results of 150 ℃ oven temperature safety tests of a battery prepared in comparative example 1 of the present invention;
Fig. 2 is a graph showing the results of the 150 c oven temperature safety test of the batteries prepared in examples 4 and 5 of the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In a first aspect, the invention provides a lithium battery positive electrode slurry, which comprises a positive electrode active material and an additive, wherein the additive is a polyisocyanate compound, and the polyisocyanate compound contains a branched chain with hydroxyl.
The polyisocyanate compound has a branched chain with hydroxyl, and can react with the carbonate electrolyte at a high temperature (above 100 ℃) to generate a jelly which can cover the surface of the anode, so that the contact between the anode and the electrolyte is isolated, and the reaction between an anode active substance and the electrolyte is inhibited; in addition, the jelly covered on the surface of the positive electrode can isolate the positive electrode and the negative electrode and increase the internal resistance of the battery, so that the thermal runaway safety problem of the battery caused by the damage of the diaphragm and the contact short circuit of the positive electrode and the negative electrode at high temperature can be prevented.
As in the artAs is well known to skilled persons, the main sources of heat for thermal runaway of a battery are that the reaction between positive and negative active materials and an electrolyte is exothermic, and short circuit caused by contact between positive and negative current collectors also generates heat, so that the internal temperature of the battery rises, and thermal runaway of the battery is caused. According to the invention, the polyisocyanate compound is added into the positive electrode slurry, so that the compound can exist stably and does not react with positive and negative electrode active materials in the conventional use of the battery. When the internal temperature of the battery is increased due to external environment and other reasons, the branched chain of the polyisocyanate compound in the anode has hydroxyl, and can react with a carbonate solvent at the temperature of over 100 ℃ to generate a jelly to cover the surface of the anode, so that the contact between the anode and the electrolyte is blocked, the exothermic reaction between the anode and the electrolyte is inhibited, the interface impedance of the battery is increased, and when the battery is short-circuited, the polarization of the battery is increased and the voltage is rapidly reduced due to the fact that the interface impedance is increased, wherein the voltage is rapidly reduced according to the formula Q = U2t/R also indicates that the short-circuit heat release amount is sharply reduced.
When preparing the anode slurry, the polyisocyanate compound is only needed to be used as an additive and mixed with other raw materials such as an anode active substance, and the lithium battery anode slurry provided by the invention can be prepared. The preparation method is simple and easy to implement, and the polyisocyanate compound can stably exist in the positive electrode slurry and can not react with other substances in the slurry such as the positive electrode active substance, so that the capacity exertion of the positive electrode active substance can not be influenced.
Further, the polyisocyanate compound contains a branched chain having a thioether bond.
The polyisocyanate compound contains thioether bonds, the lithium removal amount of the positive electrode is increased along with the increase of voltage, metal ions in the positive electrode can be changed from low price to high price, and the high-price metal ions can generate side reaction with the electrolyte, so that the electrolyte is reduced, and the cycle performance of the battery is reduced. And the thioether bond can generate a complexing effect with high-valence metal ions in the positive active material, and the formed complex can isolate the contact of the positive active material and the electrolyte, so that the reaction between the positive active material and the electrolyte can be inhibited, and the integral cycle performance of the battery is ensured. In general, the polyisocyanate compound contains hydroxyl, so that the safety performance of the battery at high temperature can be protected; the polyisocyanate compound contains thioether bonds, so that the cycling performance of the battery can be protected in conventional use.
Alternatively, the hydroxyl-containing branched chain and the thioether-containing branched chain in the polyisocyanate compound may be the same branched chain or different branched chains, and the invention is not limited thereto.
Further, the structural formula of the polyisocyanate compound is shown as the formula (1):
Wherein x is an integer of 10-700.
The additive with the structure is selected, so that the safety of the battery is improved, and the influence on the cycle performance and the rate performance of the battery is small.
Further, the polyisocyanate-based compound is selected from polyisocyanate block polymers (PAIC (OH) -b-PHIC).
Compared with a homopolymer, the block polymer is more beneficial to the transmission of lithium ions, and has less influence on the cycle performance and rate performance of the battery, so that the polyisocyanate block polymer is preferably added into the positive electrode slurry.
Further, the polyisocyanate block polymer (PAIC (OH) -b-PHIC) contains a branch chain having a thioether bond.
For the same reason as described above, the presence of a thioether bond can improve the general cycle performance of the battery.
Alternatively, the hydroxyl-containing branch and the thioether-containing branch in the polyisocyanate block polymer may be the same branch or different branches, and the present invention is not limited thereto.
Further, the polyisocyanate block polymer (PAIC (OH) -b-PHIC) has the formula shown in formula (2):
Wherein, m in the formula: n = (1:10) - (10: 1).
The polyisocyanate block polymer (PAIC (OH) -b-PHIC) with the structure improves the safety of the battery and has small influence on the cycle performance and the rate performance of the battery. The safety of the battery is improved, the normal-temperature cycle performance of the battery under the 1C multiplying power is not affected, and the cycle performance at 45 ℃ is improved. The values of m and n in the block polymer also influence the performance of the overall performance of the block polymer. When m: n is less than 1:10, the polyisocyanate segmented polymer can not well generate a jelly covering the surface of the positive electrode when the temperature in the battery rises, so that the rise of the heat in the battery can not be well inhibited, and the safety performance of the battery can not be improved; and when m: n is more than 10:1, sulfur and high-valence metal have a complexing effect, and when m is too large, partial regional impedance of the active material is increased, current is not uniform during charging and discharging, partial local overcharge is caused, and performance of the battery is attenuated.
Further, the molecular weight of the polyisocyanate-based compound was 2000-100000.
When preparing the anode slurry, selecting the polyisocyanate compound within the molecular weight range, so that the polyisocyanate compound can be uniformly dispersed on the active substance when the anode slurry is stirred; if the molecular weight is too large, the dispersion is not uniform, so that the current distribution of different areas of the positive plate obtained after coating is not uniform; if the molecular weight is too small, the compound is dissolved in the electrolyte, so that the cycle performance of the battery is influenced, and the improvement of the safety performance of the battery is also influenced.
Further, the proportion of the polyisocyanate compound in the positive electrode slurry is 0.1wt% to 10 wt%.
The mass ratio in the present invention does not include the mass of the organic solvent. When the positive electrode slurry is prepared, the proportion of the polyisocyanate compound in the positive electrode slurry is in the range, so that the battery assembled by the prepared positive electrode plate has guaranteed safety performance at high temperature, and the original performance of the battery cannot be influenced. When the proportion of the polyisocyanate compound in the positive electrode slurry is higher than 10wt%, the amount of the polyisocyanate compound is too much, so that the active substances of the positive electrode are correspondingly reduced, and the rate performance of the battery is influenced; when the proportion of the polyisocyanate compound in the positive electrode slurry is less than 0.1wt%, the polyisocyanate compound is too small in amount, so that the effects of isolating the positive electrode and increasing the internal resistance of the battery cannot be achieved, and the safety performance of the battery cannot be improved.
Further, the positive electrode active material was LiCoO2、LiNixCoyMnzO2、LiFePO4One or more of them.
Further, the conductive agent, the binder and the solvent are contained.
Wherein the conductive agent is one or more of Carbon Nanotube (CNT), acetylene black, super-P and Ketjen black; the binder is one or more of polyvinylidene fluoride (PVDF), polyacrylic acid (PAA) and lithium Polyacrylate (PAALi); the solvent is one or more of ethylene carbonate, diethyl carbonate, methyl ethyl carbonate, dimethyl carbonate, fluoroethylene carbonate and gamma-butyrolactone.
Further, the viscosity of the positive electrode slurry is 4000cP to 7000 cP.
In a second aspect, the invention provides a lithium battery positive plate, which comprises a positive current collector and positive slurry coated on the positive current collector, wherein the positive slurry is the lithium battery positive slurry.
The positive pole slurry of the lithium battery is coated on a positive pole current collector, and a positive pole piece used as the battery can be prepared through the working procedures of drying, compacting and the like. The polyisocyanate compound can stably exist in the positive plate because the polyisocyanate compound does not react with substances in the positive electrode slurry, namely the positive plate contains the polyisocyanate compound, and the compound contains a branched chain with hydroxyl. When the internal temperature of the battery formed by the positive plate rises, the polyisocyanate compound with hydroxyl can react with the carbonate electrolyte to generate a jelly which covers the surface of the positive plate, so that the contact between the positive active material and the electrolyte can be isolated, the side reaction between the positive active material and the electrolyte can be inhibited, the interface impedance of the battery can be increased, and the potential safety hazard caused by the rise of the internal temperature of the battery can be reduced.
Furthermore, the polyisocyanate compound in the positive electrode sheet may contain a thioether bond. In a conventional cycle of the battery, when the lithium of the positive electrode material is removed, metal ions in the positive electrode material can be changed from low valence to high valence, and the high valence metal ions have strong reducibility and can react with an electrolyte, so that the cycle performance of the battery is reduced. Thioether bonds in the polyisocyanate compounds can be complexed with high-valence metal ions, so that the reaction between the high-valence metal ions and an electrolyte can be prevented, and the conventional cycle performance of the battery is improved to a great extent.
In a third aspect, the invention provides a lithium battery, which comprises a positive plate, a negative plate, a diaphragm and electrolyte, wherein the positive plate is the positive plate of the lithium battery.
The positive plate of the lithium battery contains the polyisocyanate compound, and the compound can stably exist in the positive plate and does not react with other substances such as a positive active substance and the like, so that the capacity of the positive active substance is not influenced, and the normal performance of the whole capacity of the battery is ensured. In addition, when the internal temperature of the battery rises due to external or internal reasons, the polyisocyanate compound with hydroxyl in the positive plate can react with the carbonate electrolyte to generate jelly which covers the surface of the positive electrode, so that the contact between the positive electrode and the electrolyte can be isolated, and the side reaction between the positive electrode and the electrolyte can be inhibited; in addition, the generated jelly covers the surface of the positive electrode, and the positive electrode and the negative electrode are isolated, so that the contact short circuit of the positive electrode and the negative electrode caused by the damage of the diaphragm is avoided, and the high-temperature safety performance of the battery is improved.
In addition, the branched chain of the polyisocyanate compound may further contain a thioether bond, which can perform a complex reaction with high-valence metal ions, and in the battery cycle process, along with the extraction of positive electrode lithium, the valence of the metal ions in the positive electrode active material will increase, while the high-valence metal ions have high reaction activity, and can react with the electrolyte, thereby reducing the electrolyte and lowering the electrode performance. And the polyisocyanate compound with thioether bond and high valence metal ions are subjected to complex reaction, so that the contact between the electrolyte and the high valence metal ions is prevented, and the side reaction between the positive active material and the electrolyte is prevented. Therefore, the addition of the polyisocyanate compound with hydroxyl and thioether bonds ensures the safety performance of the battery at high temperature and the cycle performance of the battery in conventional use.
Further, the electrolyte comprises a solvent and a lithium salt, wherein the solvent is a carbonate solvent, and the carbonate solvent is ethylene carbonate, fluoroethylene carbonate, vinylene carbonate, gamma-butyrolactone, diethyl carbonate, ethyl methyl carbonate and dimethyl carbonate. The carbonate electrolyte contains one or more additives of ethylene sulfate, ethylene sulfite, 1, 3-propane sultone, methylene methane disulfonate and propylene sulfate.
Further, the lithium salt is LiPF6、LiTFSI、LiFSI、LiODFB、LiBOB、LiClO4One or more of them.
The present invention is further illustrated by the following specific examples, which are provided only for illustrating and explaining the present invention and are not intended to limit the present invention.
Example 1
(1) Preparation of positive plate
Mixing lithium cobaltate, CNT, polytetrafluoroethylene, PAIC (OH) -b-PHIC (Mn =30000, m: N =1: 5) and N-methylpyrrolidone according to the weight ratio of 100: 0.6: 0.5:0.5: 50 into slurry, evenly coating the slurry on two sides of the conductive matrix aluminum foil, and then drying, rolling and cutting to obtain the positive plate.
(2) Preparation of negative plate
Mixing graphite, super-P, carboxymethyl cellulose, styrene butadiene rubber and water according to the weight ratio of 100: 1: 1.5: 2: 180 weight percent to obtain uniform slurry, uniformly coating the slurry on two sides of the conductive matrix copper foil, drying, rolling and cutting to obtain the negative plate.
(3) Battery assembly
And (3) winding the positive plate, the negative plate and the polypropylene film prepared above into a pole core of a square lithium ion battery, then injecting the electrolyte into an aluminum-plastic film at the amount of 2.5g/Ah, and sealing to prepare the soft package lithium ion battery S1.
Example 2
A battery S2 was prepared using the same method steps as in example 1, except for the preparation of the positive electrode material:
Mixing lithium cobaltate, CNT, polytetrafluoroethylene, PAIC (OH) -b-PHIC (Mn =30000, m: N =5: 1) and N-methylpyrrolidone according to the weight ratio of 100: 0.6: 0.5:0.5: 50 into slurry, evenly coating the slurry on two sides of the conductive matrix aluminum foil, and then drying, rolling and cutting to obtain the positive plate.
Example 3
A battery S3 was prepared using the same method steps as in example 1, except for the preparation of the positive electrode material:
mixing lithium cobaltate, CNT, polytetrafluoroethylene, PAIC (OH) -b-PHIC (Mn =30000, m: N =1: 5) and N-methylpyrrolidone according to the weight ratio of 100: 0.6: 0.5: 2.5: 50 into slurry, evenly coating the slurry on two sides of the conductive matrix aluminum foil, and then drying, rolling and cutting to obtain the positive plate.
Example 4
A battery S4 was prepared using the same method steps as in example 1, except for the preparation of the positive electrode material:
mixing lithium cobaltate, CNT, polytetrafluoroethylene, PAIC (OH) -b-PHIC (Mn =30000, m: N =5: 1) and N-methylpyrrolidone according to the weight ratio of 100: 0.6: 0.5:2.5: 50 into slurry, evenly coating the slurry on two sides of the conductive matrix aluminum foil, and then drying, rolling and cutting to obtain the positive plate.
Example 5
A battery S5 was prepared using the same method steps as in example 1, except for the preparation of the positive electrode material:
mixing lithium cobaltate, CNT, polytetrafluoroethylene, PAIC (OH) -b-PHIC (Mn =30000, m: N =1: 5) and N-methylpyrrolidone according to the weight ratio of 100: 0.6: 0.5:5: 50 into slurry, evenly coating the slurry on two sides of the conductive matrix aluminum foil, and then drying, rolling and cutting to obtain the positive plate.
Example 6
A battery S6 was prepared using the same method steps as in example 1, except for the preparation of the positive electrode material:
mixing lithium cobaltate, CNT, polytetrafluoroethylene, PAIC (OH) -b-PHIC (Mn =30000, m: N =5: 1) and N-methylpyrrolidone according to the weight ratio of 100: 0.6: 0.5: 5: 50 into slurry, evenly coating the slurry on two sides of the conductive matrix aluminum foil, and then drying, rolling and cutting to obtain the positive plate.
Example 7
Cell DS3 was prepared using the same method steps as in example 1, except for the preparation of the positive electrode material:
mixing lithium cobaltate, CNT, polytetrafluoroethylene, PAIC (OH) -b-PHIC (Mn =30000, m: N =1: 5) and N-methylpyrrolidone according to the weight ratio of 100: 0.6: 0.5:0.1: 50 into slurry, evenly coating the slurry on two sides of the conductive matrix aluminum foil, and then drying, rolling and cutting to obtain the positive plate.
Example 8
Cell DS4 was prepared using the same method steps as in example 1, except for the preparation of the positive electrode material:
mixing lithium cobaltate, CNT, polytetrafluoroethylene, PAIC (OH) -b-PHIC (Mn =30000, m: N =1: 5) and N-methylpyrrolidone according to the weight ratio of 100: 0.6: 0.5:15: 50 into slurry, evenly coating the slurry on two sides of the conductive matrix aluminum foil, and then drying, rolling and cutting to obtain the positive plate.
Example 9
Cell DS5 was prepared using the same method steps as in example 1, except for the preparation of the positive electrode material:
mixing lithium cobaltate, CNT, polytetrafluoroethylene, PAIC (OH) -b-PHIC (Mn =30000, m: N =1: 12) and N-methylpyrrolidone according to the weight ratio of 100: 0.6: 0.5:0.5: 50 into slurry, evenly coating the slurry on two sides of the conductive matrix aluminum foil, and then drying, rolling and cutting to obtain the positive plate.
Example 10
Cell DS6 was prepared using the same method steps as in example 1, except for the preparation of the positive electrode material:
mixing lithium cobaltate, CNT, polytetrafluoroethylene, PAIC (OH) -b-PHIC (Mn =30000, m: N = 12: 1) and N-methylpyrrolidone according to the weight ratio of 100: 0.6: 0.5:0.5: 50 into slurry, evenly coating the slurry on two sides of the conductive matrix aluminum foil, and then drying, rolling and cutting to obtain the positive plate.
Comparative example 1
Cell DS1 was prepared using the same method steps as in example 1, except for the preparation of the positive electrode material:
mixing lithium cobaltate, CNT, polytetrafluoroethylene and N-methylpyrrolidone according to a weight ratio of 100: 0.6: :0.8: 50 into slurry, evenly coating the slurry on two sides of the conductive matrix aluminum foil, and then drying, rolling and cutting to obtain the positive plate.
Comparative example 2
Cell DS2 was prepared using the same method steps as in example 1, except for the preparation of the positive electrode material:
lithium cobaltate, CNT, polytetrafluoroethylene, triphenyl phosphate and N-methyl pyrrolidone are mixed according to the weight ratio of 100: 0.6: 0.5:5: 50 into slurry, evenly coating the slurry on two sides of the conductive matrix aluminum foil, and then drying, rolling and cutting to obtain the positive plate.
And (3) testing a needling experiment:
in the battery safety test, a needle-prick test is the most difficult test to pass, because the energy of the whole battery is rapidly released in a very short time through an internal short-circuit point, so that the temperature is rapidly increased in a short time, and then a chain reaction is initiated, thereby causing thermal runaway.
The batteries prepared in the above examples and comparative examples 1 to 6 were subjected to a needle punching experiment: firstly, charging and discharging the battery, wherein the charging and discharging current is 0.1C, and the charging and discharging voltage range is 3.0V-4.4V; after 0.1C cycle for 1 cycle, the charge was 4.4V and the needling experiment was performed. And simultaneously detecting the temperature change of the battery in the needling experiment. The details of the needling experiments are as follows:
The current of 1.0.2C is charged to the upper limit voltage of 4.20V (4.35V/4.40V), and the cut-off condition is 0.02C;
2. completely puncturing the center of the battery cell at a speed of 150mm/s by using a steel needle with the diameter of 3mm, and keeping the puncturing state;
3. terminating the test when the surface temperature of the battery core is reduced to below 35 ℃;
the needling experiment passed the standard: the battery does not explode, fire or smoke.
TABLE 1
TABLE 2
As can be seen from tables 1 and 2, the battery positive electrode sheet containing the polyisocyanate compound can improve the passing rate of the battery in the needle punching test, and thus can suppress thermal runaway of the battery. When the content of the polyisocyanate compound in the positive plate is lower than the range required by the invention, the effect of protecting the safety of the battery cannot be achieved; when the ratio of m to n in the added polyisocyanate block polymer is out of the range claimed in the present invention, the internal temperature of the battery is too high due to the needle punching test, and the effect of protecting the safety of the battery is not obtained.
Cycle performance test at ° c:
the battery obtained in the experiment was charged to 4.5V at a constant current of 3000mA (1C) at a temperature of 45 ℃, then charged at a constant voltage of 4.5V with a cutoff current value of 150mA, and then discharged to 3V at a constant current of 3000mA as a primary cycle; after repeating the charge and discharge cycles 300 times in this manner, the discharge capacity/first discharge capacity x 100% was calculated by the capacity remaining rate (%) after cycles = n cycles; the test results are shown in fig. 2.
TABLE 3
As can be seen from tables 1-3: the safety performance and 45 ℃ cycle performance of the battery are improved to different degrees by adding a certain amount of polyisocyanate block polymer (PAIC (OH) -b-PHIC). When the content of PAIC (OH) -b-PHIC is less than 0.1wt%, a covering material cannot be effectively formed at the positive electrode at the time of short circuit, and a side reaction between the positive electrode and the electrolyte cannot be effectively suppressed at 45 ℃; when the content of PAIC (OH) -b-PHIC is higher than 10wt%, the safety performance of the battery is improved through a needling test; but increases the interface impedance of the battery and reduces the 45 ℃ cycle performance of the battery.
Test of furnace temperature safety at C
The battery samples S4, S5, and DS1 were charged to 100% SOC at 25 ± 2 ℃ with a constant current of 0.1C, the samples were placed in an oven to be heated to 150 ± 2 ℃ at a rate of 5 ± 2 ℃ per minute and were turned to a constant temperature and held for 30 minutes, and the batteries passed the standard without firing and without explosion, and the test results are shown in fig. 1-2.
As can be seen from fig. 1-2, when the oven temperature reached 150 ℃, the voltage of the comparative example DS1 battery decreased to about 0.2v after about 10min, and the battery temperature increased above 350 ℃, and thermal runaway occurred in the battery. As can be seen from FIG. 2, the S4 and S5 batteries can be stored at 150 ℃ for 1h without thermal runaway, the voltage of the batteries is kept above 3.5v, and the temperature of the batteries is kept at about 150 ℃.
Claims (13)
1. The lithium battery positive electrode slurry is characterized by comprising a positive electrode active substance and an additive, wherein the additive is a polyisocyanate compound, and the polyisocyanate compound contains a branched chain with hydroxyl.
2. The positive electrode slurry for lithium batteries according to claim 1, wherein said polyisocyanate-based compound contains a branched chain having a thioether bond.
3. The positive electrode slurry for a lithium battery as claimed in claim 2, wherein the polyisocyanate-based compound has a structural formula of:
Wherein x is an integer of 10-700.
4. The positive electrode slurry for lithium batteries according to claim 1, wherein the polyisocyanate-based compound is a polyisocyanate block polymer.
5. The positive electrode slurry for lithium batteries according to claim 4, wherein said polyisocyanate block polymer contains a branched chain having a thioether bond.
6. The lithium battery positive electrode paste as claimed in claim 5, wherein the polyisocyanate block polymer has a structural formula of:
In the formula, m: n = (1:10) - (10: 1).
7. The lithium battery positive electrode slurry as claimed in claim 1, wherein the molecular weight of the polyisocyanate-based compound is 2000-100000.
8. The positive electrode slurry for lithium batteries according to claim 1, wherein the proportion of the polyisocyanate-based compound in the positive electrode slurry is 0.1 to 10% by weight.
9. The positive electrode slurry for lithium batteries according to claim 1, wherein said positive electrode active material is LiCoO2、LiNixCoyMnzO2（x+y+z=1, 0<x,y,z<1）、LiFePO4One or more of them.
10. The positive electrode slurry for lithium batteries according to claim 1, further comprising a conductive agent, a binder and a solvent.
11. A positive plate of a lithium battery, comprising a positive current collector and positive slurry coated on the positive current collector, wherein the positive slurry is the positive slurry of the lithium battery of any one of claims 1 to 10.
12. A lithium battery comprising a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte, wherein the positive electrode sheet is the lithium battery positive electrode sheet according to claim 11.
13. The lithium battery of claim 12, wherein the electrolyte comprises a solvent and a lithium salt, the solvent is a carbonate solvent, the carbonate solvent is ethylene carbonate, fluoroethylene carbonate, vinylene carbonate, gamma-butyrolactone, diethyl carbonate, ethyl methyl carbonate, or dimethyl carbonate, and the carbonate electrolyte contains one or more additives selected from the group consisting of ethylene sulfate, ethylene sulfite, 1, 3-propane sultone, methylene methanedisulfonate, and propylene sulfate.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109155440A (en) * | 2016-04-06 | 2019-01-04 | 魁北克电力公司 | electrolyte additive |
| CN114031778A (en) * | 2021-11-09 | 2022-02-11 | 远景动力技术(江苏)有限公司 | Electrode slurry additive, preparation method thereof, positive electrode and lithium ion battery |
| CN114927670A (en) * | 2022-06-16 | 2022-08-19 | 蜂巢能源科技股份有限公司 | Modified ternary cathode material and preparation method and application thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR19980076258A (en) * | 1997-04-08 | 1998-11-16 | 성재갑 | Cathode electrode coating liquid for lithium ion battery or lithium ion polymer battery containing isocyanate compound, cathode electrode using same and method for manufacturing same |
| CN101373848A (en) * | 2007-08-23 | 2009-02-25 | 株式会社东芝 | Nonaqueous-electrolyte battery |
| WO2018046494A1 (en) * | 2016-09-06 | 2018-03-15 | Oxis Energy Limited | Anode for an electrochemical cell |
| CN108886167A (en) * | 2016-04-12 | 2018-11-23 | 大金工业株式会社 | Electrolyte, electrochemical appliance, lithium ion secondary battery and component |
| CN109585919A (en) * | 2018-11-06 | 2019-04-05 | 欣旺达电子股份有限公司 | Lithium ion battery and its electrolyte |
-
2019
- 2019-04-28 CN CN201910348439.6A patent/CN111864192B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR19980076258A (en) * | 1997-04-08 | 1998-11-16 | 성재갑 | Cathode electrode coating liquid for lithium ion battery or lithium ion polymer battery containing isocyanate compound, cathode electrode using same and method for manufacturing same |
| CN101373848A (en) * | 2007-08-23 | 2009-02-25 | 株式会社东芝 | Nonaqueous-electrolyte battery |
| CN108886167A (en) * | 2016-04-12 | 2018-11-23 | 大金工业株式会社 | Electrolyte, electrochemical appliance, lithium ion secondary battery and component |
| WO2018046494A1 (en) * | 2016-09-06 | 2018-03-15 | Oxis Energy Limited | Anode for an electrochemical cell |
| CN109585919A (en) * | 2018-11-06 | 2019-04-05 | 欣旺达电子股份有限公司 | Lithium ion battery and its electrolyte |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109155440A (en) * | 2016-04-06 | 2019-01-04 | 魁北克电力公司 | electrolyte additive |
| CN114031778A (en) * | 2021-11-09 | 2022-02-11 | 远景动力技术(江苏)有限公司 | Electrode slurry additive, preparation method thereof, positive electrode and lithium ion battery |
| CN114927670A (en) * | 2022-06-16 | 2022-08-19 | 蜂巢能源科技股份有限公司 | Modified ternary cathode material and preparation method and application thereof |
| CN114927670B (en) * | 2022-06-16 | 2024-04-09 | 蜂巢能源科技股份有限公司 | Modified ternary positive electrode material and preparation method and application thereof |
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