CN116031362A - Positive plate and lithium ion battery - Google Patents
Positive plate and lithium ion battery Download PDFInfo
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- CN116031362A CN116031362A CN202211717747.XA CN202211717747A CN116031362A CN 116031362 A CN116031362 A CN 116031362A CN 202211717747 A CN202211717747 A CN 202211717747A CN 116031362 A CN116031362 A CN 116031362A
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- ternary
- manganese phosphate
- lithium iron
- iron manganese
- positive electrode
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- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 40
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 40
- 239000000463 material Substances 0.000 claims abstract description 122
- DVATZODUVBMYHN-UHFFFAOYSA-K lithium;iron(2+);manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[Fe+2].[O-]P([O-])([O-])=O DVATZODUVBMYHN-UHFFFAOYSA-K 0.000 claims abstract description 77
- 239000007774 positive electrode material Substances 0.000 claims abstract description 22
- 239000013078 crystal Substances 0.000 claims abstract description 19
- 239000013543 active substance Substances 0.000 claims abstract description 14
- 239000002245 particle Substances 0.000 claims description 23
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 12
- 239000010439 graphite Substances 0.000 claims description 12
- 229910002804 graphite Inorganic materials 0.000 claims description 12
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 11
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 claims description 10
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 claims description 10
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 claims description 10
- 239000003792 electrolyte Substances 0.000 claims description 7
- 239000007773 negative electrode material Substances 0.000 claims description 7
- 239000003960 organic solvent Substances 0.000 claims description 7
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 2
- 229910015645 LiMn Inorganic materials 0.000 claims 1
- 230000000052 comparative effect Effects 0.000 description 9
- 239000002131 composite material Substances 0.000 description 9
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 8
- 229910052744 lithium Inorganic materials 0.000 description 8
- 239000010405 anode material Substances 0.000 description 7
- 239000010410 layer Substances 0.000 description 6
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 239000012792 core layer Substances 0.000 description 3
- -1 graphite alkyne Chemical class 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- 239000011247 coating layer Substances 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 229910000616 Ferromanganese Inorganic materials 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- DOCYQLFVSIEPAG-UHFFFAOYSA-N [Mn].[Fe].[Li] Chemical compound [Mn].[Fe].[Li] DOCYQLFVSIEPAG-UHFFFAOYSA-N 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000008139 complexing agent Substances 0.000 description 1
- 239000011258 core-shell material Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 description 1
- ILXAVRFGLBYNEJ-UHFFFAOYSA-K lithium;manganese(2+);phosphate Chemical group [Li+].[Mn+2].[O-]P([O-])([O-])=O ILXAVRFGLBYNEJ-UHFFFAOYSA-K 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 239000011164 primary particle Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
Abstract
The invention relates to a positive plate and a lithium ion battery. The positive plate comprises a positive electrode active substance, wherein the positive electrode active substance comprises lithium iron manganese phosphate and a ternary material; the ternary material comprises a ternary single crystal material and a ternary polycrystalline material; the mass of the lithium iron manganese phosphate is more than or equal to 50wt% of the mass of the positive electrode active material. According to the invention, the ternary monocrystal, ternary polycrystal and the lithium iron manganese phosphate are mixed according to a certain proportion, wherein the lithium iron manganese phosphate accounts for more than 50wt% of the positive plate, so that the discharge double-platform voltage of the lithium iron manganese phosphate is optimized, the discharge voltage is more gentle, and the control of the BMS is facilitated; the ternary material solves the problem of double-voltage platform of lithium iron manganese phosphate discharge, and enhances the conductivity and power performance of the material.
Description
Technical Field
The invention belongs to the technical field of positive electrode materials of lithium ion batteries, and relates to a positive electrode plate and a lithium ion battery.
Background
With the wide application of new energy automobiles, a lithium ion battery with safety, reliability, high energy density and low cost becomes one of research hotspots of technological workers, and the characteristics of a positive electrode material directly influence the safety performance and the cost of the battery.
Compared with a ternary material, the safety and low cost advantages of the existing lithium iron manganese phosphate positive electrode material are obvious, the energy density is improved compared with the lithium iron phosphate material, and under the condition that the energy density of the lithium iron phosphate material is close to a theoretical extremum, the lithium ion battery needs to be further developed, the specific energy density is improved, so that the lithium iron manganese phosphate material becomes one of important points of research.
CN 109250698A discloses a high tap density lithium iron manganese phosphate anode material, a preparation method and application thereof. The positive electrode material is formed by mixing small-particle lithium iron manganese phosphate with the particle size of 0.3-0.8 mu m and large-particle lithium iron manganese phosphate with the particle size of 3-5 mu m according to the mass ratio of 1-9:9-1, and the preparation method comprises the following steps: (1) preparation of compact ferromanganese phosphate; (2) preparing large and small particle lithium iron manganese phosphate slurry; (3) preparation of lithium iron manganese phosphate precursor powder; (4) preparing a lithium iron manganese phosphate finished product; the obtained material is applied to a lithium battery anode material.
CN 104124453a discloses a lithium iron manganese phosphate composite positive electrode material, a preparation method thereof, a lithium battery positive electrode and a lithium battery. The size of the lithium iron manganese phosphate composite anode material is nano, graphite alkyne is compounded in the lithium iron manganese phosphate base material, and the mass of the graphite alkyne is that of the lithium iron manganese phosphate0.1 to 10 percent of the mass of the lithium base material. Adding a nanoscale lithium source, a nanoscale manganese source, a nanoscale iron source and a nanoscale phosphorus source into a solvent according to the molar ratio of each element of lithium iron phosphate, dissolving to form a solution, sequentially adding a complexing agent and a graphite alkyne solution into the solution, and then drying, grinding, sintering, annealing and the like. The lithium battery anode and the lithium battery all contain the lithium manganese iron phosphate composite anode material. Lithium iron manganese phosphate composite positive electrode material shortens Li from aspect of reducing primary particle size + And electron migration paths, thereby improving the conductivity of the material. The preparation method can ensure the stable performance of the lithium iron manganese phosphate composite anode material. The lithium battery has high discharge gram capacity and cycle capacity retention rate.
The CN 114512649A is a composite lithium iron manganese phosphate anode material, the composite lithium iron manganese phosphate anode material is of a core-shell structure, and comprises an inner core layer, a transition layer, an outer shell layer and a coating layer from inside to outside in sequence, wherein the inner core layer is lithium manganese phosphate, the transition layer is lithium iron manganese phosphate, the outer shell layer is lithium iron phosphate, and the coating layer is carbon-coated; the composite lithium iron phosphate positive electrode material is spherical or spheroid particles, and the chemical composition of the composite lithium iron phosphate positive electrode material is LiMn α Fe β PO 4 C; the inner core layer is xLiMnPO 4 The transition layer is yLiMn a Fe b PO 4 The outer shell layer is zLiFePO 4 Where x+y+z=1, z is less than or equal to 0.05, x+ya=α, yb+z=β.
Despite the great advantages of lithium iron manganese phosphate materials, there are major drawbacks in practical applications. Firstly, a double-voltage platform exists in the lithium iron manganese phosphate material in the discharging process, the voltage difference between the two discharging platforms is large, and the voltage is suddenly reduced due to the existence of the two voltage platforms in the actual use process, so that the BMS voltage is difficult to collect; in addition, the manganese element is doped in the lithium iron manganese phosphate material, so that the conductivity of the material is reduced, and the low-temperature discharge capability is poor.
Therefore, how to solve the problem of dual-voltage platform of lithium iron manganese phosphate discharge is a technical problem to be solved.
Disclosure of Invention
In order to solve the technical problems, the invention provides the positive plate and the lithium ion battery, wherein ternary monocrystal, ternary polycrystal and lithium iron manganese phosphate are mixed according to a certain proportion, wherein the lithium iron manganese phosphate accounts for more than 50wt% of the positive plate, the discharge double-platform voltage of the lithium iron manganese phosphate is optimized, the discharge voltage is more gentle, and the BMS control is facilitated; the ternary material solves the problem of double-voltage platform of lithium iron manganese phosphate discharge, and enhances the conductivity and power performance of the material.
To achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a positive electrode sheet, wherein the positive electrode sheet includes a positive electrode active material, and the positive electrode active material includes lithium iron manganese phosphate and a ternary material;
the ternary material comprises a ternary single crystal material and a ternary polycrystalline material;
the mass of the lithium iron manganese phosphate is equal to or greater than 50wt% of the mass of the positive electrode active material, and may be, for example, 50wt%, 60wt%, 70wt%, 80wt% or 95wt%, but is not limited to the values recited, and other values not recited in the numerical range are equally applicable.
According to the invention, the ternary monocrystal, ternary polycrystal and the lithium iron manganese phosphate are mixed according to a certain proportion, wherein the lithium iron manganese phosphate accounts for more than 50wt% of the positive plate, so that the discharge double-platform voltage of the lithium iron manganese phosphate is optimized, the discharge voltage is more gentle, and the control of the BMS is facilitated; the ternary material solves the problem of double-voltage platform of lithium iron manganese phosphate discharge, and enhances the conductivity and power performance of the material.
Preferably, the mass of the lithium iron manganese phosphate is 60 to 80wt% of the mass of the positive electrode active material, for example, 60wt%, 65wt%, 70wt%, 75wt% or 80wt%, but not limited to the recited values, and other non-recited values within the numerical range are equally applicable.
Preferably, the mass ratio of the ternary monocrystalline material to the ternary polycrystalline material is 0.25-0.4, for example, 0.25, 0.28, 0.3, 0.35, 0.38 or 0.4, but not limited to the recited values, and other non-recited values in the numerical range are equally applicable.
The ternary single crystal material and the ternary polycrystalline material are mixed, so that the effect of balancing the voltage of the double platforms of the lithium iron manganese phosphate can be achieved, the discharge platform voltage of the reference electrode can be improved by the special single crystal material, the discharge platform voltage of the doped material can be further improved, the transmission path of lithium ions is reduced by adding the polycrystalline material, the resistance is reduced, and the power performance and the low-temperature performance of the material are improved.
The positive plate provided by the invention not only solves the application problem of the lithium iron manganese phosphate material, but also can improve the performance of the ternary material, and ensures the safety, reliability and low cost of the positive plate.
Preferably, the ternary material comprises any one or a combination of at least two of an 8-series ternary material, a 7-series ternary material, or a 6-series ternary material, and typical but non-limiting combinations include a combination of an 8-series ternary material and a 7-series ternary material, a combination of a 7-series ternary material and a 6-series ternary material, a combination of an 8-series ternary material and a 6-series ternary material, or a combination of an 8-series ternary material, a 7-series ternary material, and a 6-series ternary material.
Preferably, the lithium iron manganese phosphate has a chemical formula of LiMn x Fe 1-x PO 4 X is 0.3 to 0.7, and may be, for example, 0.3, 0.4, 0.5, 0.6 or 0.7, but is not limited to the values recited, and other values not recited in the numerical range are equally applicable.
The particle size of the lithium manganese iron phosphate is preferably in the range of 1 to 5. Mu.m, for example, 1. Mu.m, 2. Mu.m, 3. Mu.m, 4. Mu.m, or 5. Mu.m, but not limited to the values recited, and other values not recited in the numerical range are equally applicable.
Preferably, the ternary monocrystalline material has a particle size ranging from 3 to 40 μm, for example, 3 μm, 5 μm, 10 μm, 20 μm, 30 μm or 40 μm, but not limited to the recited values, and other values not recited in the range of values are equally applicable.
Preferably, the ternary polycrystalline material has a particle size ranging from 1 to 16 μm, for example, 1 μm, 5 μm, 10 μm, 12 μm, or 16 μm, but is not limited to the recited values, and other values not recited in the range of values are equally applicable.
In a second aspect, the present invention provides a lithium ion battery, which contains the positive electrode sheet according to the first aspect.
Preferably, the negative electrode material in the lithium ion battery comprises graphite and/or carbon-coated graphite.
Preferably, the lithium ion battery is a liquid battery.
Preferably, the organic solvent in the electrolyte employed by the lithium ion battery comprises any one or a combination of at least two of ethylene carbonate, methyl ethyl carbonate or dimethyl carbonate, and typical but non-limiting combinations include a combination of ethylene carbonate and methyl ethyl carbonate, a combination of methyl ethyl carbonate and dimethyl carbonate, a combination of ethylene carbonate and dimethyl carbonate, or a combination of ethylene carbonate, methyl ethyl carbonate and dimethyl carbonate.
Compared with the prior art, the invention has at least the following beneficial effects:
according to the invention, the ternary monocrystal, ternary polycrystal and the lithium iron manganese phosphate are mixed according to a certain proportion, wherein the lithium iron manganese phosphate accounts for more than 50wt% of the positive plate, so that the discharge double-platform voltage of the lithium iron manganese phosphate is optimized, the discharge voltage is more gentle, and the control of the BMS is facilitated; the ternary material solves the problem of double-voltage platform of lithium iron manganese phosphate discharge, and enhances the conductivity and power performance of the material.
Detailed Description
To facilitate understanding of the present invention, examples are set forth below. 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.
Example 1
The embodiment provides a lithium ion battery, which comprises a positive plate and a negative plate.
The positive plate comprises a positive electrode active substance, wherein the positive electrode active substance comprises lithium iron manganese phosphate and a ternary material; the ternary material NCM (811) comprises a ternary single crystal material and a ternary polycrystalline material with a mass ratio of 0.3; the grain diameter of the ternary monocrystal material ranges from 3 mu m to 40 mu m, and the grain diameter of the ternary polycrystal material ranges from 1 mu m to over16 μm. The lithium iron manganese phosphate (LiMn) x Fe 1-x PO 4 X is 0.5) accounts for 85wt% of the positive electrode active material mass, and the particle size is 1-5 μm.
The negative electrode material in the negative electrode plate is graphite.
The organic solvent in the electrolyte adopted by the lithium ion battery comprises ethylene carbonate, methyl ethyl carbonate and dimethyl carbonate.
Example 2
The embodiment provides a lithium ion battery, which comprises a positive plate and a negative plate.
The positive plate comprises a positive electrode active substance, wherein the positive electrode active substance comprises lithium iron manganese phosphate and a ternary material; the ternary material NCM (712) comprises a ternary single crystal material and a ternary polycrystalline material with a mass ratio of 0.28; the grain size range of the ternary monocrystal material is 3-40 mu m, and the grain size range of the ternary polycrystal material is 1-16 mu m. The lithium iron manganese phosphate (LiMn) x Fe 1-x PO 4 X is 0.7) is 80wt% based on the mass of the positive electrode active material, and the particle diameter is 1 to 5 μm.
The negative electrode material in the negative electrode plate is graphite.
The organic solvent in the electrolyte adopted by the lithium ion battery comprises ethylene carbonate, methyl ethyl carbonate and dimethyl carbonate.
Example 3
The embodiment provides a lithium ion battery, which comprises a positive plate and a negative plate.
The positive plate comprises a positive electrode active substance, wherein the positive electrode active substance comprises lithium iron manganese phosphate and a ternary material; the ternary material NCM (622) comprises a ternary single crystal material and a ternary polycrystalline material with the mass ratio of 0.35; the grain size range of the ternary monocrystal material is 3-40 mu m, and the grain size range of the ternary polycrystal material is 1-16 mu m. The lithium iron manganese phosphate (LiMn) x Fe 1-x PO 4 X is 0.3) is 90wt% of the positive electrode active material mass, and the particle diameter is 1 to 5 μm.
The negative electrode material in the negative electrode plate is graphite.
The organic solvent in the electrolyte adopted by the lithium ion battery comprises ethylene carbonate, methyl ethyl carbonate and dimethyl carbonate.
Example 4
The embodiment provides a lithium ion battery, which comprises a positive plate and a negative plate.
The positive plate comprises a positive electrode active substance, wherein the positive electrode active substance comprises lithium iron manganese phosphate and a ternary material; the ternary material NCM (811) comprises a ternary single crystal material and a ternary polycrystalline material with a mass ratio of 0.25; the grain size range of the ternary monocrystal material is 3-40 mu m, and the grain size range of the ternary polycrystal material is 1-16 mu m. The lithium iron manganese phosphate (LiMn) x Fe 1-x PO 4 X is 0.4) by mass of the positive electrode active material is 50% by mass, and the particle diameter is 1 to 5 μm.
The negative electrode material in the negative electrode plate is graphite.
The organic solvent in the electrolyte adopted by the lithium ion battery comprises ethylene carbonate, methyl ethyl carbonate and dimethyl carbonate.
Example 5
The embodiment provides a lithium ion battery, which comprises a positive plate and a negative plate.
The positive plate comprises a positive electrode active substance, wherein the positive electrode active substance comprises lithium iron manganese phosphate and a ternary material; the ternary material NCM (811) comprises a ternary single crystal material and a ternary polycrystalline material with a mass ratio of 0.4; the grain size range of the ternary monocrystal material is 3-40 mu m, and the grain size range of the ternary polycrystal material is 1-16 mu m. The lithium iron manganese phosphate (LiMn) x Fe 1-x PO 4 X is 0.6) by mass of the positive electrode active material is 50% by mass, and the particle diameter is in the range of 1 to 5 μm.
The negative electrode material in the negative electrode plate is graphite.
The organic solvent in the electrolyte adopted by the lithium ion battery comprises ethylene carbonate, methyl ethyl carbonate and dimethyl carbonate.
Example 6
This example provides a lithium ion battery that differs from example 1 in that the mass ratio of ternary single crystal material to ternary polycrystalline material is 0.2.
Example 7
This example provides a lithium ion battery that differs from example 1 in that the mass ratio of ternary single crystal material to ternary polycrystalline material is 0.5.
Example 8
This example provides a lithium ion battery differing from example 1 in that the particle size of lithium iron manganese phosphate ranges from 6 to 9 μm.
Example 9
This example provides a lithium ion battery differing from example 1 in that the particle size of lithium iron manganese phosphate ranges from 10 to 14 μm.
Example 10
This example provides a lithium ion battery that differs from example 1 in that the ternary monocrystalline material has a particle size in the range of 41-45 μm.
Example 11
This example provides a lithium ion battery that differs from example 1 in that the ternary polycrystalline material has a particle size in the range of 17 to 20 μm.
Comparative example 1
This comparative example provides a lithium ion battery that differs from example 1 in that the ternary single crystal material is replaced with an equal quality ternary polycrystalline material.
Comparative example 2
This comparative example provides a lithium ion battery that differs from example 1 in that the ternary polycrystalline material is replaced with an equal quality ternary single crystal material.
Comparative example 3
This comparative example provides a lithium ion battery differing from example 1 in that the mass of lithium iron manganese phosphate is 45wt% of the mass of the positive electrode active material.
The lithium ion battery obtained above was subjected to electrochemical performance test, and the test results are shown in table 1.
TABLE 1
From table 1, the following conclusions can be drawn:
(1) As can be seen from examples 1-5 and comparative examples 1-3, according to the invention, by mixing ternary single crystals, ternary polycrystal and lithium iron manganese phosphate according to a certain proportion, wherein the lithium iron manganese phosphate accounts for more than 50wt% of the positive plate, the discharge double-platform voltage of the lithium iron manganese phosphate is optimized, so that the discharge voltage is more gentle, and the control of a BMS (battery management system) is facilitated; the ternary material solves the problem of double-voltage platform of lithium iron manganese phosphate discharge, and enhances the conductivity and power performance of the material.
In comparative example 3, the performance of the power is high due to the increased mass of the ternary material, however, the cost of the material in the positive electrode sheet is increased, and comparison of example 1 with comparative example 3 shows that when the mass ratio of the lithium manganese iron phosphate to the ternary material is improved, the advantages of ensuring excellent power performance and reducing the cost can be achieved.
(2) As can be seen from comparison of examples 6 and 7 with example 1, when the mass ratio of the ternary single crystal material to the ternary polycrystalline material is not within the range of 0.25-0.4, the application problem of the lithium iron manganese phosphate material is solved by influencing the positive plate, and the performance of the ternary material is not improved, so that the safety and reliability of the positive plate material cannot be guaranteed and the cost is low.
(3) As can be seen from comparison of examples 8 and 9 with example 1, when the particle size range of the lithium manganese iron phosphate is not within the preferred range of the present invention, the application problem of the lithium manganese iron phosphate material is solved by influencing the positive electrode sheet, so that the safety and reliability of the positive electrode material cannot be ensured and the cost is low.
(4) As can be seen from comparison of examples 10 and 11 with example 1, when the particle size range of the ternary single crystal material or ternary polycrystalline material is not within the preferred range of the present invention, the ternary material is affected to solve the problem of dual voltage plateau of lithium manganese iron phosphate discharge and is disadvantageous in enhancing the conductivity and power performance of the material.
In summary, according to the invention, by mixing the ternary monocrystal, ternary polycrystal and lithium iron manganese phosphate according to a certain proportion, wherein the lithium iron manganese phosphate accounts for more than 50wt% of the positive plate, the discharge double-platform voltage of the lithium iron manganese phosphate is optimized, so that the discharge voltage is more gentle, and the control of the BMS is facilitated; the ternary material solves the problem of double-voltage platform of lithium iron manganese phosphate discharge, and enhances the conductivity and power performance of the material.
The detailed process equipment and process flow of the present invention are described by the above embodiments, but the present invention is not limited to, i.e., it does not mean that the present invention must be practiced depending on the detailed process equipment and process flow. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of raw materials for the product of the present invention, addition of auxiliary components, selection of specific modes, etc., falls within the scope of the present invention and the scope of disclosure.
Claims (10)
1. The positive plate is characterized by comprising a positive active substance, wherein the positive active substance comprises lithium iron manganese phosphate and a ternary material;
the ternary material comprises a ternary single crystal material and a ternary polycrystalline material;
the mass of the lithium iron manganese phosphate is more than or equal to 50wt% of the mass of the positive electrode active material.
2. The positive electrode sheet according to claim 1, wherein the mass of the lithium iron manganese phosphate is 60 to 80wt% of the mass of the positive electrode active material.
3. The positive electrode sheet according to claim 1 or 2, wherein the mass ratio of the ternary single crystal material to the ternary polycrystalline material is 0.25 to 0.4.
4. The positive electrode sheet of any one of claims 1-3, wherein the ternary material comprises any one or a combination of at least two of an 8-series ternary material, a 7-series ternary material, or a 6-series ternary material.
5. The positive electrode sheet according to any one of claims 1 to 4, wherein the lithium iron manganese phosphate has a chemical formula of LiMn x Fe 1-x PO 4 X is 0.3 to 0.7.
6. The positive electrode sheet according to any one of claims 1 to 5, wherein the particle size of the lithium iron manganese phosphate is in the range of 1 to 5 μm.
7. The positive electrode sheet according to any one of claims 1 to 6, wherein the ternary single crystal material has a particle diameter in the range of 3 to 40 μm;
preferably, the ternary polycrystalline material has a particle size in the range of 1 to 16 μm.
8. A lithium ion battery, wherein the lithium ion battery comprises the positive plate according to any one of claims 1 to 7.
9. The lithium ion battery of claim 8, wherein the negative electrode material in the lithium ion battery comprises graphite and/or carbon-coated graphite.
10. The lithium ion battery of claim 8 or 9, wherein the lithium ion battery is a liquid battery;
preferably, the organic solvent in the electrolyte used in the lithium ion battery comprises any one or a combination of at least two of ethylene carbonate, methyl ethyl carbonate and dimethyl carbonate.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116914087A (en) * | 2023-09-13 | 2023-10-20 | 中创新航科技集团股份有限公司 | Lithium iron manganese phosphate battery |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116914087A (en) * | 2023-09-13 | 2023-10-20 | 中创新航科技集团股份有限公司 | Lithium iron manganese phosphate battery |
| CN116914087B (en) * | 2023-09-13 | 2023-11-24 | 中创新航科技集团股份有限公司 | Lithium iron manganese phosphate battery |
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