A kind of anode plate for lithium ionic cell and preparation method thereof
Technical field
The present invention relates to field of lithium ion battery, particularly relate to a kind of good cycle, cycle life is high, also can improve anode plate for lithium ionic cell of the cryogenic property of battery and preparation method thereof simultaneously.
Background technology
Along with the fast development of electric motor car and hybrid-power electric vehicle, for having higher power density and energy density, the demand of the power-type lithium ion battery being suitable for fast charging and discharging and the energy type lithium ion battery with more permanent flying power is very urgent.
Along with the development of lithium ion battery industry, lithium ion battery applications is more and more wider, and the requirement of market to lithium ion battery is also more and more higher, especially require more and more higher to the energy density of lithium ion battery, particularly in today that electric vehicle engineering is day by day perfect, lithium-ion-power cell not only requires higher energy density to ensure the course continuation mileage of electric automobile, also need that there is excellent cycle life simultaneously, and negative material is as one of the core of lithium ion battery, improving its cycle life while ensureing negative material high power capacity is also one of effective way solved the problem.
Chinese patent publication No. CN101807725A, date of publication on August 18th, 2010, name is called lithium ion battery, this application case discloses a kind of lithium ion battery, comprise battery case and the stacked cathode sheets being wound into electrode group, anode strip and barrier film, cathode sheets comprises cathode current collector and is attached to the negative electrode diaphragm on cathode current collector, anode strip comprises anode collector and is attached to the anode diaphragm in anode collector, between barrier film interval and adjacent anode and cathode slice, cathode current collector is made up of graphite material, cathode sheets and anode strip are provided with the exposed division of uncoated Yin/Yang pole diaphragm respectively in its width direction, on the negative electrode that exposed division is electrically connected on battery case respectively as lug and anode.Its weak point is, cycle life is short, and specific capacity is low.
Summary of the invention
The object of the invention is to adopt native graphite to make the defect of cycle performance of battery difference and provide good cycle to solve existing lithium ion battery negative material, cycle life is high, also can improve the anode plate for lithium ionic cell of the cryogenic property of battery simultaneously.
Another object of the present invention is the manufacture method in order to provide a kind of anode plate for lithium ionic cell.
To achieve these goals, the present invention is by the following technical solutions:
A kind of anode plate for lithium ionic cell, comprise negative current collector, described negative current collector applies negative electrode material layer, negative electrode material layer applies soft carbon-coating, described soft carbon-coating is made up of soft carbon, conductive agent and binding agent.In the technical program, the interplanar distance of soft material with carbon element is large compared with graphite material, deviates from process in which materials deformation relatively little, at Lithium-ion embeding especially when high power charging-discharging, not easily cause negative material to peel off and efflorescence, effectively can suppress the decay of battery capacity.On the other hand, soft material with carbon element and compatibility of electrolyte good, the SEI membrane structure formed in its surface is form compact and stable, effectively can prevent the common embedding of solvent molecule simultaneously, effectively improve cycle performance of battery.
As preferably, negative material composition and each weight percentages of components are respectively: negative electrode active material 88-96%, conductive agent 0.5-6%, sodium carboxymethylcellulose 1-2.5%, butadiene-styrene rubber 1.5-3.5%.
As preferably, described negative electrode active material is one or both mixing in electrographite, native graphite, conductive agent is one or more mixing in conductive black, superconduction carbon, electrically conductive graphite, carbon nano-fiber or carbon nano-tube, and butadiene-styrene rubber is emulsion form, and solid content is 50%.
As preferably, the component of soft carbon-coating and percentage by weight thereof are respectively soft carbon 80-96%, conductive agent 2-10%, binding agent 2-10%.
As preferably, conductive agent is one or more in conductive black, superconduction carbon, electrically conductive graphite, carbon nano-fiber and carbon nano-tube, and binding agent is Kynoar.
As preferably, collector is the Copper Foil of thickness 5-15 μm.
A manufacture method for anode plate for lithium ionic cell, described preparation method comprises the steps:
A) preparation of cathode size: sodium carboxymethylcellulose CMC is dissolved in deionized water, the CMC glue that solid content is 1.6-1.8% is obtained after dispersed with stirring 3-5h, then conductive agent is added the dispersed with stirring of carrying out 1-2h in CMC glue, then divide and add negative electrode active material n time, the interval time that each negative material adds is 0.5h, each addition is the 1/n of negative electrode active material gross mass, after high-speed stirred 5-6h, add styrene butadiene rubber sbr again, add deionized water after uniform stirring 2-4h and carry out slurry viscosity adjustment, slurry viscosity is controlled at 2000-8000cps,
B) cathode size step a) obtained is coated on negative current collector Copper Foil equably, after 80-110 DEG C, 10-12h toast drying, obtain coated negative electrode material layer;
C) preparation of soft carbon pastes: first Kynoar is dissolved in organic solvent 1-METHYLPYRROLIDONE, after 4-12h stirs, make it be dissolved completely in solvent obtain the glue that solid content is 4-10%, again conductive agent is dispersed in above-mentioned glue, after the high-speed stirred dispersion of 1-2h, add the high speed dispersion that soft carbon dust material carries out 2-4h, slurry viscosity controls at 6000-10000cps;
D) step c) is obtained soft carbon pastes be coated on the negative electrode material layer that step b) completes equably, after 90-105 DEG C, 12-16h toast drying, obtain semi-finished product negative plate.
As preferably, the Thickness Ratio scope of negative electrode material layer and soft carbon-coating is at 5:1-25:1, and the THICKNESS CONTROL of negative electrode material layer is at 100-200 μm, and the THICKNESS CONTROL of soft carbon-coating is at 4-40 μm.
As preferably, compacted density when negative plate rolls is 1.2-1.5g/cm
3.
The invention has the beneficial effects as follows:
1) lithium ion battery negative material raw material sources provided by the invention are wide, preparation method is simple, obtained lithium ion battery negative material has high power capacity, high rate capability, and Stability Analysis of Structures, not easily react with electrolyte, do not reunite, thus make lithium ion battery have higher durability and cyclical stability;
2) interplanar distance of soft material with carbon element is large compared with graphite material, deviates from process in which materials deformation relatively little, especially when high power charging-discharging, not easily cause negative material to peel off and efflorescence, effectively can suppress the decay of battery capacity at Lithium-ion embeding.On the other hand, soft material with carbon element and compatibility of electrolyte good, the SEI membrane structure formed in its surface is form compact and stable, effectively can prevent the common embedding of solvent molecule simultaneously, effectively improve cycle performance of battery;
3) soft carbon pastes is coated in the compatibility that negative electrode material layer not only can increase negative plate and electrolyte by the present invention equably, reduce the generation of negative pole and electrolyte side reaction, also can reduce the expansion of negative pole to a certain extent, thus improve the cycle performance of battery, also can improve the cryogenic property of battery simultaneously.
Accompanying drawing explanation
Fig. 1 to be the embodiment of the present invention 1 with comparative example 1 circulate correlation curve figure.
Embodiment
Below by specific embodiment, technical scheme of the present invention is described in further detail.
In the present invention, if not refer in particular to, the raw material adopted and equipment etc. all can be buied from market or this area is conventional.
Embodiment 1
A kind of manufacture method of anode plate for lithium ionic cell, described manufacture method comprises the steps: the preparation of a) cathode size: be dissolved in 1230g deionized water by 20g sodium carboxymethylcellulose CMC, the CMC glue that solid content is about 1.6% is obtained after dispersed with stirring 5h, then 10gVGCF and 10gSP is added the dispersed with stirring of carrying out 1h in CMC glue, then 935g native graphite average mark is added for 2 times, the interval time that 2 negative materials add is 0.5h, after high-speed stirred 3h, add the styrene butadiene rubber sbr emulsion that 25g solid content is 50% again, after uniform stirring 2h, test slurry viscosity is 2600cps, now slurry solid content is 36%,
B) cathode size prepared being coated in equably thickness is on 10 μm of negative current collector Copper Foils, and coated side density is 200g/m
2, through 100 DEG C, 10h obtains coated negative electrode material layer after toasting drying.
C) preparation of soft carbon pastes: first 40g Kynoar is dissolved in 460g organic solvent 1-METHYLPYRROLIDONE, after 6h stirs, make it be dissolved completely in solvent obtain the glue that solid content is 8%, again 60g conductive agent VGCF is dispersed in above-mentioned glue, the high speed dispersion that the soft carbon dust material of 900g carries out 3h is added after the high-speed stirred dispersion of 1h, add 300gN-methyl pyrrolidone afterwards and carry out viscosity adjustment, final slurry viscosity is 8400cps, and solid content is 56.7%;
D) be coated in equably by the soft carbon pastes prepared on negative electrode material layer that above-mentioned preparation completes, coated side density is 25g/m
2, through 105 DEG C, 14h obtains semi-finished product negative plate after toasting drying.Now the thickness of negative electrode material layer is 186 μm, and the thickness of soft carbon-coating is 29 μm.
First rolled by the semi-finished product negative plate obtained, compacted density is 1.4g/cm
3, be then washed into the negative plate of the shape required for us.
The negative plate that above process is obtained is assembled into flexible-packed battery.That positive electrode adopts is LiNi
1/3co
1/3mn
1/3o
2positive electrode.
Embodiment 2
A kind of manufacture method of anode plate for lithium ionic cell, described manufacture method comprises the steps: the preparation of a) cathode size: be dissolved in 545.55g deionized water by 10g sodium carboxymethylcellulose CMC, the CMC glue that solid content is about 1.8% is obtained after dispersed with stirring 4h, then 2.5g electrically conductive graphite and 2.5gSP are added the dispersed with stirring of carrying out 1.5h in CMC glue, then 960g native graphite average mark is added for 4 times, the interval time that each negative material adds is 0.5h, after high-speed stirred 5.5h, add the styrene butadiene rubber sbr emulsion that 15g solid content is 50% again, after uniform stirring 3h, test slurry viscosity is 5600cps, now slurry solid content is 46%,
B) cathode size prepared being coated in equably thickness is on 15 μm of negative current collector Copper Foils, and coated side density is 200g/m
2, through 80 DEG C, 12h obtains coated negative electrode material layer after toasting drying.
C) preparation of soft carbon pastes: first 20g Kynoar is dissolved in 480g organic solvent 1-METHYLPYRROLIDONE, after 4h stirs, make it be dissolved completely in solvent obtain the glue that solid content is 4%, again by 20g conductive agent carbon nanotube dispersed to above-mentioned glue, the high speed dispersion that the soft carbon dust material of 960g carries out 2h is added after the high-speed stirred dispersion of 1.5h, add 300gN-methyl pyrrolidone afterwards and carry out viscosity adjustment, final slurry viscosity is 8400cps, and solid content is 56.7%;
D) be coated in equably by the soft carbon pastes prepared on negative electrode material layer that above-mentioned preparation completes, coated side density is 25g/m
2, through 90 DEG C, 16h obtains semi-finished product negative plate after toasting drying.Now the thickness of negative electrode material layer is 100 μm, and the thickness of soft carbon-coating is 4 μm.
First rolled by the semi-finished product negative plate obtained, compacted density is 1.2g/cm
3, be then washed into the negative plate of the shape required for us.
The negative plate that above process is obtained is assembled into flexible-packed battery.That positive electrode adopts is LiNi
1/3co
1/3mn
1/3o
2positive electrode.
Embodiment 3
A kind of manufacture method of anode plate for lithium ionic cell, described manufacture method comprises the steps: the preparation of a) cathode size: be dissolved in 1641.67g deionized water by 25g sodium carboxymethylcellulose CMC, the CMC glue that solid content is about 1.5% is obtained after dispersed with stirring 5h, then 60g superconduction carbon is added the dispersed with stirring of carrying out 2h in CMC glue, then 880g native graphite average mark is added for 3 times, the interval time that each negative material adds is 0.5h, after high-speed stirred 6h, add the styrene butadiene rubber sbr emulsion that 35g solid content is 50% again, after uniform stirring 4h, test slurry viscosity is 8000cps, now slurry solid content is 36%,
B) cathode size prepared being coated in equably thickness is on 5 μm of negative current collector Copper Foils, and coated side density is 200g/m
2, through 110 DEG C, 11h obtains coated negative electrode material layer after toasting drying;
C) preparation of soft carbon pastes: first 100g Kynoar is dissolved in 900g organic solvent 1-METHYLPYRROLIDONE, after 12h stirs, make it be dissolved completely in solvent obtain the glue that solid content is 10%, again 50g conductive agent VGCF and 50g superconduction carbon are dispersed in above-mentioned glue, the high speed dispersion that the soft carbon dust material of 800g carries out 4h is added after the high-speed stirred dispersion of 2h, add 300gN-methyl pyrrolidone afterwards and carry out viscosity adjustment, final slurry viscosity is 10000cps, and solid content is 56.7%;
D) be coated in equably by the soft carbon pastes prepared on negative electrode material layer that above-mentioned preparation completes, coated side density is 25g/m
2, through 100 DEG C, 16h obtains semi-finished product negative plate after toasting drying.Now the thickness of negative electrode material layer is 200 μm, and the thickness of soft carbon-coating is 40 μm.
First rolled by the semi-finished product negative plate obtained, compacted density is 1.5g/cm
3, be then washed into the negative plate of the shape required for us.
The negative plate that above process is obtained is assembled into flexible-packed battery.That positive electrode adopts is LiNi
1/3co
1/3mn
1/3o
2positive electrode.
Comparative example 1
Negative electrode material layer coated in above-described embodiment 1 is directly carried out rolling punching as negative plate, then is assembled into the flexible-packed battery in same embodiment 1.
Battery in battery in embodiment 1 and comparative example 1 is carried out 1C/1C charge-discharge test under discharge and recharge cut-ff voltage is 2.7-4.2V condition, and following form is the information of the capacity of two kinds of batteries, weight, energy density:
|
Battery capacity (Ah) |
Battery weight (g) |
Battery energy density (Wh/kg) |
Embodiment 1 |
38.5 |
830 |
170 |
Comparative example 1 |
38.5 |
810 |
173 |
Battery in battery in embodiment 1 and comparative example 1 is carried out the test of 1C/1C charge-discharge performance under discharge and recharge cut-ff voltage is 2.7-4.2V condition, sees Fig. 1;
As seen from the above table, under same battery system, the energy density of embodiment 1 battery is also a little less than comparative example 1 battery.But from above circulation comparison diagram embodiment 1 battery relative to comparative example 1 cycle performance improve clearly, through the charge and discharge cycles of 550 weeks, the capability retention of embodiment 1 battery is 87.79%, and the capability retention of comparative example 1 battery is 83.98%.Sum up above result known, the energy density of embodiment 1 battery has reduction slightly compared with comparative example 1, but it is little to reduce amplitude influences, and cycle performance is but greatly improved simultaneously.