CN113224277B - High-safety long-cycle-life positive pole piece for lithium ion battery - Google Patents
High-safety long-cycle-life positive pole piece for lithium ion battery Download PDFInfo
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Abstract
The invention discloses a high-safety long-cycle life positive pole piece for a lithium ion battery, which consists of a current collector and a positive coating, wherein the positive coating comprises a positive active material, a conductive agent and a binder, and is characterized in that: the positive active material is a mixture composed of layered lithium polybasic acid, a layered manganese-rich lithium-based material, olivine-structured lithium iron manganese and spinel lithium manganate coated with the layered manganese-rich lithium-based material, wherein the coated layered manganese-rich lithium-based material is less than or equal to 5% by mass, the non-coated layered manganese-rich lithium-based material is 5-25% by mass, the olivine-structured lithium iron manganese is less than or equal to 30% by mass, and the balance is the spinel lithium manganate or the mixture of the layered lithium polybasic acid and the spinel lithium manganate. The lithium ion battery adopting the positive pole piece has the safety performance and the normal-temperature cycle life which are close to those of a lithium iron phosphate positive pole battery, the high-temperature cycle life of a ternary positive pole battery, the low-temperature discharge capacity of a lithium manganate positive pole battery, moderate battery energy density and high cost performance.
Description
Technical Field
The invention relates to a lithium ion battery, in particular to a positive pole piece for the lithium ion battery, and particularly relates to a long-cycle-life positive pole piece for the lithium ion battery.
Background
In lithium ion batteries, common cathode materials are shown in the following table:
the ternary positive electrode material (lithium nickel cobalt manganese oxide or lithium nickel cobalt aluminate) is generally used for replacing lithium cobalt oxide and is applied to the field of power batteries. The ternary anode material has the advantages of low-temperature discharge capacity, normal-temperature circulation and high-temperature circulation, and has the highest energy density. It can be seen from the table that the gram capacity of the material gradually increases with the increase of the nickel content, but at the same time, the thermal decomposition temperature of the material decreases, which leads to the reduction of the lithium ion battery safety of the ternary cathode material system. On the other hand, a low nickel ternary material such as 111 ternary has a high cobalt content and therefore is expensive, and when the nickel content exceeds 70% (nickel content is more than the sum of nickel, cobalt, manganese or aluminum), for example, a high nickel 811 ternary material requires an oxygen atmosphere during sintering and therefore is expensive.
The synthesis of the ternary material of the anode needs oxygen to participate in the reaction, generally, manufacturers only sinter under the air condition under the condition of medium and low nickel, and sinter under the oxygen atmosphere under the condition of high nickel (1-x-y-z is more than 0.7). In addition, high nickel is sensitive to air humidity, so that moisture is easily absorbed to cause lithium carbonate to be produced on the surface of the material, and the humidity requirements of packaging and battery batching coating are strict, so that the labor cost of high nickel is higher than that of medium nickel. In recent years, safety accidents of long-endurance-mileage electric automobiles with high-nickel ternary matching frequently occur, so that the heat of the industry for high-nickel ternary is reduced, and the pursuit of high-nickel is gradually shifted to the use of medium-nickel ternary. In the medium nickel ternary, with advances in development and driving market driven costs down to accelerate the use of low cobalt-free ternary, the cobalt content (x) has now been gradually reduced to 0.05 or even 0.03. However, the natural association of cobalt and nickel in the mineral products, namely 3-5% of cobalt in pure nickel, does not need to spend the cost to remove the cobalt content in the high-nickel ternary.
The lithium manganate material is obviously superior to a ternary cathode material in safety performance, excellent in low-temperature and rate performance, and the lowest in price, but low in gram-volume (110 mAh/g), and poor in cycle life, particularly high-temperature cycle. Therefore, lithium manganate is difficult to be used alone as a positive electrode material.
Lithium iron phosphate is a common anode material of a lithium ion battery, and the cycle life of the lithium iron phosphate is longLong, excellent in safety performance, but poor in conductivity, so that the rate performance is compensated for by a small particle size in commercial use. Even so, lithium iron is difficult to discharge electricity at low temperature, and in addition, because its discharge capacity concentrates on the platform area, leads to the state of charge to be difficult with voltage calibration, leads to user's use experience very poor. The compaction density of the lithium iron is low and is only 2.4-2.5 g/cm3While the lithium manganate can reach 3.1g/cm3The ternary positive electrode can reach 3.4/cm3In addition, since the voltage of lithium iron is only 3.2V, the volume energy density of lithium iron is very low. Based on this, LiMnPO4、LiCoPO4、LiNiPO4、LiMnSiO4、LiFeSiO4、LiCoSiO4、LiNiPSiO4Is expected to replace lithium iron phosphate. The commercialization of the phosphoric acid system is more mature than the silicate system. The four elements of manganese, cobalt, nickel and iron have the highest price of cobalt and nickel and the lowest price of manganese and iron. However, lithium manganese phosphate has very poor conductivity and is inferior to lithium iron phosphate, so that lithium manganese phosphate is the most commercialized material at present, but the conductivity is inferior to that of lithium iron phosphate, the low-temperature discharge capability is weaker, and the lithium manganese phosphate is difficult to be used as a cathode material alone. The platform voltage of the lithium manganese iron phosphate reaches 4.1V, the medium voltage reaches 3.9V, the gram capacity and the cycle life of the lithium manganese iron phosphate are consistent with those of lithium iron phosphate, the safety performance of a 4.2-4.3V system is extremely high, and the lithium manganese iron phosphate is applied to the mixed doping of a ternary material to improve the safety performance of overcharge and acupuncture.
The lithium-rich manganese-based material is represented as a novel anode material, the specific capacity can reach more than 250mAh/g when the lithium-rich manganese-based material is charged to 4.8V, but the cycle is unstable. The mainstream of the mature commercialized electrolyte at present is a 4.2V system, the single crystal is matched with the electrolyte of a 4.3-4.4V system in a ternary mode, and the electrolyte of a 5V high-voltage system is not mature, so that the lithium-rich manganese-based material cannot be widely used.
The Chinese patent application CN103022458A discloses a high-safety lithium ion cathode material and a lithium ion battery using the same, comprising primary particles of lithium ion metal oxide and PTC high molecular polymer with good conductivity, wherein the lithium ion metal oxide and the PTC high molecular polymer are pretreated to obtain secondary particles uniformly doped with the lithium ion metal oxide and the PTC high molecular polymer. When the temperature of the battery is increased to 80 ℃ or above, the doped PTC high molecular polymer expands in volume to block the connection between the anode particles, and the resistance of the doped PTC high molecular polymer rapidly increases to block the current, so that the safety of the lithium ion battery is effectively ensured. The scheme improves the safety of the lithium ion battery by doping the PTC high molecular polymer, but does not consider the influence of the selection of the positive active material on the performance of the lithium ion.
The Chinese invention patent application CN104362370A discloses a lithium manganate lithium ion battery and a preparation method thereof, wherein an anode electroactive material is formed by mixing spinel lithium manganate and a layered lithium-rich manganese-based material in proportion, and the mass of the layered lithium-rich manganese-based material accounts for 1-40% of the mass of the total active material. According to the invention, the spinel lithium manganate material and the layered lithium-rich manganese-based material are mixed for use, and the layered lithium-rich manganese-based material can inhibit the dissolution of manganese by optimizing the mixing ratio, so that the lithium manganate lithium ion battery with low cost, good thermal stability and excellent high-temperature performance is obtained. The Chinese invention patent CN107086298B discloses a core-shell heterogeneous lithium ion battery composite positive electrode material composed of a layered lithium-rich manganese base and spinel lithium manganate and a preparation method thereof. According to the method, the spinel lithium manganate is coated by the layered lithium-rich manganese base, the contact of the lithium manganate and an electrolyte is effectively isolated due to the existence of the coating layer, and the cycle performance of the lithium manganate material is improved. The technical scheme pays attention to the improvement of lithium manganate cycle by the lithium-rich manganese material, but how to consider the cycle performance, safety and low-temperature discharge capacity of the cathode material is still an important direction of research in the field.
The Chinese invention patent CN104300123B discloses a mixed anode material, which is prepared by compounding a ternary material and lithium manganese iron phosphate, and has the advantages of excellent electrochemical performance, high energy density, high safety performance and long cycle life. In fact, the conductivity of lithium manganese iron phosphate is inferior to that of lithium iron phosphate, so that the commercialized particle size of lithium manganese iron phosphate is smaller than that of lithium iron phosphate, and the viscosities of pure ternary slurry and lithium iron phosphate slurry are completely different, so that the coating problem is larger when lithium manganese iron phosphate and ternary complex are compounded, and the problems of coating cracking and material dropping cannot be solved at all after the content of common lithium manganese iron phosphate exceeds 30%. The pure ternary blended lithium ferric manganese phosphate has low safety performance, weak low-temperature discharge capacity and low cost performance.
Disclosure of Invention
The invention aims to provide a high-safety long-cycle-life lithium ion battery positive pole piece, which is excellent in safety performance, long in cycle life, low in price, high in cost performance and strong in low-temperature discharge capacity.
In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows: a high-safety long-cycle-life positive pole piece for a lithium ion battery is composed of a current collector and a positive pole coating coated on the surface of the current collector, wherein the positive pole coating comprises a positive pole active material, a conductive agent and a binder, the positive pole active material is a mixture composed of layered lithium polybasic acid, a layered manganese-rich lithium-based material, olivine-structure lithium iron manganese and spinel lithium manganese coated with the layered manganese-rich lithium-based material, in the positive pole active material, the coated layered manganese-rich lithium-based material is less than or equal to 5% by mass, the non-coated layered manganese-rich lithium-based material is 5-25% by mass, the olivine-structure lithium iron manganese is less than or equal to 30% by mass, and the balance is spinel lithium manganese oxide or a mixture of the layered lithium polybasic acid and the spinel lithium manganese oxide;
wherein the molecular formula of the layered lithium polybasic acid is Li1+xNiyCozM1-y-zO2Wherein x is more than or equal to-0.05 and less than or equal to 0.2, y is more than or equal to 0.5 and less than or equal to 0.7, z is more than 0 and less than or equal to 0.2, and M is one or more of Mg, Al, Ti, Ca, Sr, Cr and Ba; the molecular formula of the layered manganese-rich lithium-based material is dLi2MnO3·(1-d) Li1+aNibCocD1-b-cO2 Wherein D is one or more of Ni, Co, Mn, Mg, Al, Zn, Ti, Ca, Sr, Cr, Ba and P, D is more than or equal to 0.3 and less than or equal to 0.4, a is more than or equal to-0.05 and less than or equal to 0.2, b is more than or equal to 0 and less than or equal to 1, and c is more than or equal to 0 and less than or equal to 1; the molecular formula of spinel lithium manganate is Li1+lMn2-mVmO4-nFnWherein l is more than or equal to 0.05 and less than or equal to 0.2, m is more than or equal to 0 and less than or equal to 0.2, n is more than or equal to 0 and less than or equal to 0.2, and V is one or more of Co, Mg, Al, Ni, Zn, Ti, Ca, Sr, Cr and Ba; oliveThe molecular formula of the stone-structure lithium iron manganese is Li1+oMnpFeqL1-p-qQO4O is more than or equal to 0.05 and less than or equal to 0.2, p is more than 0 and less than 1, Q is more than 0 and less than 1, L is one or more of Co, Ni, Al, Mg, Zn, Ti, Ca, Sr, Cr and Ba, and Q is one or more of P, Si.
In the technical scheme, the positive active material is formed by adopting a mixture of various different substances, and the performance of the positive active material is improved by utilizing the synergistic effect. Wherein increasing the specific capacity of the lithium-rich manganese material requires increasing Li1+xNiyCozD1-y-zO2So that d is small, and in order to make Li2MnO3The content of Ni and Co needs to be reduced as much as possible due to the fact that the d is large, and the inventor selects d to be more than or equal to 0.3 and less than or equal to 0.4 to enable the layered manganese-rich lithium-based material dLi2MnO3·(1-d) Li1+ xNiyCozD1-y-zO2The specific capacity of the system is high in 4.2-4.3V, and the cost is low. The lithium manganate, rich lithium manganese, lithium polybasic acid, four kinds of materials of lithium manganese iron phosphate are mixed and used under a 4.3V system, the existence of the lithium manganate ensures the low-temperature discharge capacity, cost performance and safety performance of the battery, the existence of the rich lithium manganese ensures the circulation, especially high-temperature circulation capacity of the battery, the capacity of the early stage of the rich lithium manganese circulation is increased and the too fast attenuation of the early stage of the lithium manganate circulation is neutralized, so that the rich lithium manganese needs to be matched with the lithium manganate for use, the energy density and the circulation capacity of the battery are ensured by the existence of the lithium polybasic acid, the safety performance of the battery is further ensured and the battery is filled in gaps among other three kinds of materials, and therefore, the energy density of the system is improved, and the circulation capacity is further improved.
According to the preferable technical scheme, in the positive electrode active material, the coated layered manganese-rich lithium-based material accounts for 0-2% by mass.
In the technical scheme, the median particle diameter D50 of the particles of the layered manganese-rich lithium-based material is 5-10 μm.
The spinel lithium manganate material has a particle median diameter D50 of 5-20 μm, and can be single crystal or polycrystal.
The median particle diameter D50 of the layered lithium polybasic acid material is 5-15 μm, and the layered lithium polybasic acid material can be single crystal or polycrystal.
The median particle size D50 of the olivine-structure lithium iron manganese material is 0-2 μm.
The olivine-structure lithium iron manganese material can improve the conductivity by carbon coating or carbon compounding.
Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:
1. according to the invention, through compounding the positive active materials in a specific proportion, the lithium ion battery adopting the positive pole piece has the safety performance and normal-temperature cycle life close to those of a lithium iron phosphate positive battery, the high-temperature cycle life of a ternary positive battery, the low-temperature discharge capacity of a lithium manganate positive battery and moderate battery energy density.
2. The active material of the positive pole piece for the lithium ion battery has high cost performance.
Drawings
FIG. 1 is a graph of a cycle performance test according to a first embodiment of the present invention;
FIG. 2 is a diagram of an ambient temperature cycle for lithium manganese and lithium manganate enrichment;
FIG. 3 is a diagram of an atmospheric temperature cycle of ternary and lithium iron phosphate;
FIG. 4 is a graph showing the cycle performance test of the second embodiment of the present invention;
FIG. 5 is a graph showing the cycle performance test of the fifth embodiment of the present invention.
Detailed Description
The invention is further described with reference to the following figures and examples:
the first embodiment is as follows: adopts 6 series lithium nickel cobalt manganese LiNi0.6Co0.15Mn0.25O2Layered manganese-rich lithium-based material 0.3Li2MnO3·0.7LiMO2 (M＝MnaNibCo1-a-bA is more than or equal to 0 and b is less than or equal to 1) and is coated with 0.3Li2MnO3·0.7LiMO2Lithium manganate LiMn of2O4The mixture of the three substances is used as an active material of a positive plate of a lithium ion battery, wherein the mixture comprisesThe proportion of the clad layered lithium-rich manganese-based material to the positive active material is 1%, the proportion of the non-clad layered lithium-rich manganese-based material to the positive active material is 19%, the proportion of the layered nickel cobalt lithium manganate material to the positive active material is 40%, and the proportion of the spinel lithium manganate material to the positive active material is 40%.
The positive electrode active material is mixed with a conductive agent and a binder to prepare positive electrode slurry. In the slurry, the proportion of solid matters is 97.2% of active materials, 1.7% of conductive agents (conductive carbon black, conductive graphite, conductive carbon nanotubes and graphene) and 1.1% of binders (polyvinylidene fluoride). The content of the solvent N-methyl pyrrolidone is adjusted to ensure that the solid content of the slurry is about 75 percent. And coating the uniformly stirred slurry on the surface of a current collector aluminum foil, drying, rolling and slicing to obtain the positive pole piece.
The square full cell assembled by the positive pole piece is used for carrying out cycle performance test. As shown in FIG. 1, the capacity retention rate was 98.01% after 300 cycles at room temperature and 93.84% after 300 cycles at 45 ℃. According to the conjecture, the normal-temperature cycle life of the battery can reach 3000 times, and the cycle life at 45 ℃ is close to 1000 times. The discharge capacity of the battery at the temperature of minus 20 ℃ accounts for 85 percent of the nominal capacity, is higher than 80 percent of that of a ternary system battery, and is far higher than 50 percent of that of a lithium iron phosphate system battery. Generally, the 45 ℃ cycle life of the ternary system battery can reach more than 1200 times, and the 45 ℃ cycle life of the lithium iron phosphate system battery can reach 1000 times. The normal-temperature cycle life of the battery of the embodiment reaches the ternary level and is close to the normal-temperature cycle life of a lithium iron phosphate system battery; the high-temperature cycle life reaches the level of lithium iron phosphate and is close to that of a ternary system battery; the energy density is 180Wh/kg, which is higher than 160Wh/kg of lithium iron and lower than high-risk ternary 240 Wh/kg; meanwhile, the lithium manganate-based battery has the low-temperature discharge capacity, moderate battery energy density and safety performance. The positive electrode active material cost was ((0.4 × 2.8+0.4 × 13+0.2 × 8) × 10000)/((0.4 × 110 × 3.7+0.4 × 180 × 3.6+0.2 × 120 × 3.7) × 1000) =0.155 yuan/Wh, which was lower than the ternary system.
The embodiment has lower cost while meeting the application of high temperature, normal temperature and low temperature, so that the battery has high cost performance, can be applied to the field of automobile-grade power batteries, and has extremely strong market competitiveness.
Comparative example:
the full battery with the lithium-rich manganese material as the anode generally has faster normal-temperature cycle decay in a 4.8V system, and has cycle life of only 200-300 times. With the reduction of the upper charging limit voltage, the cycle of the lithium-rich manganese material is improved, wherein the cycle is 700-800 times in a 4.6V system, 800-900 times in a 4.5V system, more than 1800 times in a 4.3V system and more than 2000 times in a 4.2V system. Referring to fig. 2, a normal temperature cycle chart of lithium-rich manganese and lithium manganate is shown. Under a normal temperature 4.2V system, the lithium-rich manganese material xLi2MnO3·(1-x)LiMO2 (M＝MnaNibCo1-a-bA is more than or equal to 0, b is more than or equal to 1, x is more than or equal to 0.3 and less than or equal to 0.4), the discharge capacity is firstly rapidly increased and then slowly increased to the highest point (120 mAh/g), and then slowly decreased after stabilization. Under a normal-temperature 4.2V system, the discharge capacity of the spinel lithium manganate material is firstly quickly attenuated and then is gradually attenuated, the capacity retention rate is 75.3% after 500 times of circulation is attenuated from 110mAh/g to 82.8mAh/g, and the circulation life of the lithium manganate material is only 300 times.
Referring to fig. 3, a normal temperature cycle chart of ternary lithium iron phosphate and lithium iron phosphate is shown. In a normal-temperature 4.2V system, after 622 ternary cycles for 1000 times, the discharge specific capacity is attenuated to 165.9mAh/g from 180mAh/g, and the capacity retention rate is 92.17%. Under a normal-temperature 3.8V system, after lithium iron phosphate is cycled for 1000 times, the discharge specific capacity is attenuated to 141.8mAh/g from 150mAh/g, and the capacity retention rate is 94.53%. According to the conjecture, the normal-temperature cycle life of the ternary material can reach more than 2500 times, and the normal-temperature cycle life of the lithium iron phosphate material can reach 3500 times.
Example two: adopts 5 series nickel cobalt lithium manganate LiNi0.5Co0.2Mn0.3O2Layered manganese-rich lithium-based material 0.4Li2MnO3·0.6LiMO2 (M＝MnaNibCo1-a-bA is more than or equal to 0 and b is less than or equal to 1) and is coated with 0.4Li2MnO3·0.6LiMO2Lithium manganate LiMn of2O4The three mixtures are used as the anode pole piece of the lithium ion batteryThe active material of (1) is characterized in that the proportion of the clad layered lithium-rich manganese-based material in the positive active material is 2%, the proportion of the non-clad layered lithium-rich manganese-based material in the positive active material is 8%, the proportion of the layered nickel-cobalt lithium manganate material in the positive active material is 20%, and the proportion of the spinel lithium manganate material in the positive active material is 70%.
The positive electrode active material is mixed with a conductive agent and a binder to prepare positive electrode slurry. In the slurry, the proportion of solid matters is 97.2% of active materials, 1.7% of conductive agents (conductive carbon black, conductive graphite, conductive carbon nanotubes and graphene) and 1.1% of binders (polyvinylidene fluoride). The content of the solvent N-methyl pyrrolidone is adjusted to ensure that the solid content of the slurry is about 75 percent. And coating the uniformly stirred slurry on the surface of a current collector aluminum foil, drying, rolling and slicing to obtain the positive pole piece.
The square full cell assembled by the positive pole piece is used for carrying out cycle performance test. As shown in fig. 4, the capacity retention rate was 92.31% after 500 cycles at room temperature and 79.60% after 500 cycles at 45 ℃. According to the conjecture, the normal-temperature cycle life of the battery can reach 1300 times, and the cycle life at 45 ℃ is close to 500 times. The discharge capacity of the battery at 20 ℃ below zero accounts for 90 percent of the nominal capacity, is higher than 80 percent of that of a ternary system battery, and is far higher than 50 percent of that of a lithium iron phosphate system battery. The battery of the embodiment has far super lithium iron phosphate with low-temperature discharge capability and good safety, and the cycle life at normal temperature and high temperature can meet the requirement of general use. The positive electrode active material cost was ((0.7 × 2.8+0.2 × 12+0.1 × 8) × 10000)/((0.7 × 110 × 3.7+0.2 × 170 × 3.6+0.1 × 120 × 3.7) × 1000) =0.114 yuan/Wh. The battery meets the normal-temperature circulation, high-temperature circulation and low-temperature discharge capacities of general requirements, is lower in cost, is suitable for the small power markets for civil use such as electric bicycles and has strong market competitiveness.
Example three: 65 series nickel cobalt lithium manganate LiNi is adopted0.65Co0.05Mn0.3O2Layered manganese-rich lithium-based material 0.3Li2MnO3·0.7LiMO2 (M＝MnaNibCo1-a-bA is more than or equal to 0 and b is less than or equal to 1) and is coated with 0.3Li2MnO3·0.7LiMO2Lithium manganate LiMn of2O4The mixture of the three substances is used as an active material of a positive plate of the lithium ion battery, wherein the proportion of the clad layered lithium-rich manganese-based material to the positive active material is 1%, the proportion of the non-clad layered lithium-rich manganese-based material to the positive active material is 19%, the proportion of the layered nickel cobalt lithium manganate material to the positive active material is 40%, and the proportion of the spinel lithium manganate material to the positive active material is 40%.
The positive electrode active material is mixed with a conductive agent and a binder to prepare positive electrode slurry. In the slurry, the proportion of solid matters is 97.2% of active materials, 1.7% of conductive agents (conductive carbon black, conductive graphite, conductive carbon nanotubes and graphene) and 1.1% of binders (polyvinylidene fluoride). The content of the solvent N-methyl pyrrolidone is adjusted to ensure that the solid content of the slurry is about 75 percent. And coating the uniformly stirred slurry on the surface of a current collector aluminum foil, drying, rolling and slicing to obtain the positive pole piece.
The cycle performance of the square full battery assembled by the positive pole piece is close to that of the 6-series nickel cobalt lithium manganate in the first embodiment. The positive electrode active material cost was ((0.4 × 2.8+0.4 × 13.3+0.2 × 8) × 10000)/((0.4 × 110 × 3.7+0.4 × 185 × 3.6+0.2 × 120 × 3.7) × 1000) =0.155 yen/Wh. The energy density of the battery is 190Wh/kg, which is improved by 5.6 percent compared with 180Wh/kg of the first embodiment, but the cost is not increased.
Example four: adopts 55 series nickel cobalt lithium manganate LiNi0.55Co0.03Mn0.42O2Layered manganese-rich lithium-based material 0.4Li2MnO3·0.6LiMO2 (M＝MnaNibCo1-a-bA is more than or equal to 0 and b is less than or equal to 1) and is coated with 0.4Li2MnO3·0.6LiMO2Lithium manganate LiMn of2O4The three mixtures are used as active materials of a positive pole piece of the lithium ion battery, the proportion of the clad layered lithium-rich manganese-based material to the positive active material is 2%, the proportion of the non-clad layered lithium-rich manganese-based material to the positive active material is 8%, the proportion of the layered nickel-cobalt lithium manganate material to the positive active material is 20%, and the proportion of the spinel lithium manganate material to the positive active materialThe proportion of the material is 70%.
The positive electrode active material is mixed with a conductive agent and a binder to prepare positive electrode slurry. In the slurry, the proportion of solid matters is 97.2% of active materials, 1.7% of conductive agents (conductive carbon black, conductive graphite, conductive carbon nanotubes and graphene) and 1.1% of binders (polyvinylidene fluoride). The content of the solvent N-methyl pyrrolidone is adjusted to ensure that the solid content of the slurry is about 75 percent. And coating the uniformly stirred slurry on the surface of a current collector aluminum foil, drying, rolling and slicing to obtain the positive pole piece.
The cycle performance of the square full cell assembled by the positive pole piece is close to that of the 5-series nickel cobalt lithium manganate in the second embodiment. The positive electrode active material cost was ((0.7 × 2.8+0.2 × 12.3+0.1 × 8) × 10000)/((0.7 × 110 × 3.7+0.2 × 175 × 3.6+0.1 × 120 × 3.7) × 1000) =0.115 yen/Wh. The energy density of the battery is 160Wh/kg, which is improved by 6.7 percent compared with 150Wh/kg of the second embodiment, and the cost is increased by 0.001 yuan/Wh.
Example five: adopts 55 series nickel cobalt lithium manganate LiNi0.55Co0.03Mn0.42O2Layered manganese-rich lithium-based material 0.4Li2MnO3·0.6LiMO2 (M＝MnaNibCo1-a-bA is more than or equal to 0 and b is less than or equal to 1) is coated with 0.4Li2MnO3·0.6LiMO2Lithium manganate LiMn of2O4And lithium manganese iron phosphate LiMn0.6Fe0.4PO4The four mixtures are used as active materials of a positive pole piece of the lithium ion battery, the proportion of the clad layered lithium-rich manganese-based material to the positive active material is 2%, the proportion of the non-clad layered lithium-rich manganese-based material to the positive active material is 13%, the proportion of the layered nickel-cobalt lithium manganate material to the positive active material is 15%, the proportion of the spinel lithium manganate material to the positive active material is 50%, and the proportion of the olivine lithium manganese iron phosphate is 20%.
The positive electrode active material is mixed with a conductive agent and a binder to prepare positive electrode slurry. In the slurry, the proportion of solid matters is 97.2% of active materials, 1.7% of conductive agents (conductive carbon black, conductive graphite, conductive carbon nanotubes and graphene) and 1.1% of binders (polyvinylidene fluoride). The content of the solvent N-methyl pyrrolidone is adjusted to ensure that the solid content of the slurry is about 75 percent. And coating the uniformly stirred slurry on the surface of a current collector aluminum foil, drying, rolling and slicing to obtain the positive pole piece.
The cycle performance of the square full cell assembled by the positive pole piece is close to that of the 5-series nickel cobalt lithium manganate in the second embodiment. The cost of the positive electrode active material is ((0.5 × 2.8+0.15 × 12.3+0.15 × 8+0.2 × 5) × 10000)/((0.5 × 110 × 3.7+0.15 × 175 × 3.6+0.15 × 120 × 3.7+0.2 × 150 × 3.9) × 1000) =0.113 yuan/Wh, which is far lower than the index of 0.35 yuan/Wh required in 2025 in "energy saving and new energy automobile technical scheme 2.0" published by the chinese automobile engineering society in 10 months and 27 months in 2020. The energy density of the battery is 175Wh/kg, which is slightly reduced by 2.8 percent compared with 180Wh/kg in example 1, but the cost is reduced by 27.1 percent compared with 0.155 yuan/Wh in example one, and the cost is lowest and the cost performance is highest.
A VDA standard (DIN 91252-2016) square 2614891-sized battery cell is selected, the same negative electrode material and the same diaphragm are adopted, and the maximum single-sided surface density of the negative electrode is 110g/m2The surface density of the anode is designed according to the proportion of the anode to the cathode of 1.1, and a needling test is carried out according to the safety requirement and test method of the power storage battery for the electric automobile (GB/T31485-. From the results in table 1, in the single positive electrode material system, the lithium iron phosphate and the lithium manganese iron phosphate have the highest needling and overcharge passage rate, the lithium manganese and lithium manganese are enriched, the pure ternary passage rate is the lowest, the safety coefficient is the lowest, and the commercial application has great potential safety hazard. After the lithium manganate and the lithium-rich manganese are used for ternary mixing, the needling and overcharge passing rate is greatly improved compared with the original ternary mixing, and the passing rate is further improved after the lithium ferric manganese phosphate is further added for mixing.
TABLE 1
The square full cell assembled by the positive pole piece is used for carrying out cycle performance test. As shown in FIG. 5, the capacity retention rate was 98.96% after 200 cycles at room temperature, and 97.33% after 200 cycles at 45 ℃. According to the conjecture, the normal-temperature cycle life of the battery can reach more than 3800 times, and the cycle life of the battery at 45 ℃ is close to 1500 times. The discharge capacity of the battery at 20 ℃ below zero accounts for 84 percent of the nominal capacity, is slightly higher than 80 percent of that of a ternary system battery, and is far higher than 50 percent of that of a lithium iron phosphate system battery. Generally, the 45 ℃ cycle life of the ternary system battery can reach more than 1200 times, and the 45 ℃ cycle life of the lithium iron phosphate system battery can reach 1000 times. The cycle life of the battery of the embodiment exceeds that of lithium iron phosphate and ternary batteries at normal temperature; the high-temperature cycle life exceeds that of ternary lithium iron phosphate; the energy density is 180Wh/kg, which is higher than 160Wh/kg of lithium iron and lower than high-risk 811 ternary 240 Wh/kg; meanwhile, the lithium manganate-based battery has the low-temperature discharge capacity, moderate battery energy density and safety performance.
Claims (8)
1. The utility model provides a high safe long cycle life lithium ion battery uses positive pole piece, comprises the mass flow body and the anodal coating of coating on the mass flow body surface, anodal coating includes anodal active material, conductive agent and binder, its characterized in that: the positive active material is a mixture composed of layered multi-lithium manganate, a layered manganese-rich lithium-based material, olivine-structure iron manganese lithium and spinel lithium manganate coated with the layered manganese-rich lithium-based material, or the positive active material is a mixture composed of the layered manganese-rich lithium-based material, olivine-structure iron manganese lithium and spinel lithium manganate coated with the layered manganese-rich lithium-based material, in the positive active material, by mass, the coated layered manganese-rich lithium-based material is 1% -5%, the non-coated layered manganese-rich lithium-based material is 5-25%, the olivine-structure iron manganese lithium is less than or equal to 30%, and the balance is the spinel lithium manganate or the mixture of the layered multi-lithium and the spinel lithium manganate, wherein the lithium manganate content is more than the lithium manganese;
wherein the molecular formula of the layered lithium polybasic acid is Li1+xNiyCozM1-y-zO2Wherein x is more than or equal to-0.05 and less than or equal to 0.2, y is more than or equal to 0.5 and less than or equal to 0.7, z is more than 0 and less than or equal to 0.2, and M is one or more of Mg, Al, Ti, Ca, Sr, Cr and Ba; the molecular formula of the layered manganese-rich lithium-based material is dLi2MnO3·(1-d) Li1+aNibCocD1-b-cO2 Wherein D is one or more of Ni, Co, Mn, Mg, Al, Zn, Ti, Ca, Sr, Cr, Ba and P, D is more than or equal to 0.3 and less than or equal to 0.4, a is more than or equal to-0.05 and less than or equal to 0.2, b is more than or equal to 0 and less than or equal to 1, and c is more than or equal to 0 and less than or equal to 1; the molecular formula of spinel lithium manganate is Li1+lMn2-mVmO4-nFnWherein l is more than or equal to 0.05 and less than or equal to 0.2, m is more than or equal to 0 and less than or equal to 0.2, n is more than or equal to 0 and less than or equal to 0.2, and V is one or more of Co, Mg, Al, Ni, Zn, Ti, Ca, Sr, Cr and Ba; the molecular formula of olivine-structure lithium iron manganese is Li1+oMnpFeqL1-p-qQO4O is more than or equal to 0.05 and less than or equal to 0.2, p is more than 0 and less than 1, Q is more than 0 and less than 1, L is one or more of Co, Ni, Al, Mg, Zn, Ti, Ca, Sr, Cr and Ba, and Q is one or more of P, Si.
2. The positive electrode sheet for a lithium ion battery having high safety and long cycle life according to claim 1, wherein: in the positive electrode active material, the coated layered manganese-rich lithium-based material is 0-2% by mass and is not 0.
3. The positive electrode sheet for a lithium ion battery having high safety and long cycle life according to claim 1, wherein: the particle median diameter D50 of the layered manganese-rich lithium-based material is 5-10 μm.
4. The positive electrode sheet for a lithium ion battery having high safety and long cycle life according to claim 1, wherein: the spinel lithium manganate material has a particle median diameter D50 of 5-20 μm, and can be single crystal or polycrystal.
5. The positive electrode sheet for a lithium ion battery having high safety and long cycle life according to claim 1, wherein: the median particle diameter D50 of the layered lithium polybasic acid material is 5-15 μm, and the layered lithium polybasic acid material can be single crystal or polycrystal.
6. The positive electrode sheet for a lithium ion battery having high safety and long cycle life according to claim 1, wherein: the median particle size D50 of the olivine-structure lithium iron manganese material is 0-2 μm.
7. The positive electrode sheet for a lithium ion battery having high safety and long cycle life according to claim 1 or 6, wherein: the olivine-structure lithium iron manganese material is carbon-compounded to improve conductivity.
8. The positive electrode sheet for a lithium ion battery having high safety and long cycle life according to claim 7, wherein: the olivine-structure lithium iron manganese material is coated with carbon to improve conductivity.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103996820A (en) * | 2014-05-30 | 2014-08-20 | 南京安普瑞斯有限公司 | Lithium ion battery as well as mixed positive electrode and active material with synergistic effect |
| CN106571456A (en) * | 2016-11-09 | 2017-04-19 | 浙江兴海能源科技股份有限公司 | Anode compounded material of lithium ion battery |
| CN107528050A (en) * | 2017-08-08 | 2017-12-29 | 上海华普汽车有限公司 | Active substance of lithium ion battery anode, positive electrode, positive electrode slurry, positive plate, its preparation method and lithium ion battery |
| CN109546109A (en) * | 2018-11-12 | 2019-03-29 | 合肥斯姆雷品牌管理有限公司 | A kind of high-temperature stable lithium battery anode |
| CN111883771A (en) * | 2020-09-14 | 2020-11-03 | 天津斯科兰德科技有限公司 | Lithium ion battery positive electrode material, positive plate and lithium ion battery |
-
2021
- 2021-05-03 CN CN202110487003.2A patent/CN113224277B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103996820A (en) * | 2014-05-30 | 2014-08-20 | 南京安普瑞斯有限公司 | Lithium ion battery as well as mixed positive electrode and active material with synergistic effect |
| CN106571456A (en) * | 2016-11-09 | 2017-04-19 | 浙江兴海能源科技股份有限公司 | Anode compounded material of lithium ion battery |
| CN107528050A (en) * | 2017-08-08 | 2017-12-29 | 上海华普汽车有限公司 | Active substance of lithium ion battery anode, positive electrode, positive electrode slurry, positive plate, its preparation method and lithium ion battery |
| CN109546109A (en) * | 2018-11-12 | 2019-03-29 | 合肥斯姆雷品牌管理有限公司 | A kind of high-temperature stable lithium battery anode |
| CN111883771A (en) * | 2020-09-14 | 2020-11-03 | 天津斯科兰德科技有限公司 | Lithium ion battery positive electrode material, positive plate and lithium ion battery |
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