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A technical method to improve the first-time efficiency of lithium-ion full batteries

A full battery, lithium ion technology, applied in the field of improving the first efficiency of lithium ion full battery, can solve problems such as lithium precipitation and lithium metal safety hazards, achieve safe and reliable first efficiency, make up for the loss of active lithium, and improve first efficiency Effect

Active Publication Date: 2020-12-11
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although this method can also play the role of pre-lithiation of the negative electrode sheet, the thickness of the lithium sheet currently available on the market is about 45um, which is far beyond the amount that the negative electrode can absorb. Not only is there too much lithium metal in the battery There are potential safety hazards, and it is also easy to cause lithium precipitation in the cycle

Method used

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  • A technical method to improve the first-time efficiency of lithium-ion full batteries

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] (1) 5% of the quality of 622 nickel cobalt lithium manganese oxide in the material ratio of the positive pole piece is weighed to take Li 3 V 2 (PO 4 ) 3 The material is added to the positive electrode material, and the positive electrode sheet is made according to the normal mixing, coating, rolling, and cutting processes;

[0018] (2) The positive electrode sheet obtained in step (1) is discharged with metallic lithium as the counter electrode, the lower limit of the control voltage is 1.2V, the active lithium of the negative electrode is inserted into the positive electrode, and the Li in the positive electrode sheet 3 V 2 (PO 4 ) 3 Materials intercalate lithium to obtain Li 3+x V 2 (PO 4 ) 3 (1≤x≤2);

[0019] (3) Under the -40 degree dew point environment, assemble the positive electrode sheet obtained in step (2) and the SiO / C composite negative electrode sheet with a gram capacity of 450mAh / g that meets the full battery design to form a full battery. A...

Embodiment 2

[0021] (1) Weigh Li according to 12% of the NCA mass in the material ratio of the positive pole piece. 3 V 2 (PO 4 ) 3 The material is added to the positive electrode material, and the positive electrode sheet is made according to the normal mixing, coating, rolling, and cutting processes;

[0022] (2) The positive electrode sheet obtained in step (1) is discharged with metallic lithium as the counter electrode, the lower limit of the control voltage is 1.2V, the active lithium of the negative electrode is inserted into the positive electrode, and the Li in the positive electrode sheet 3 V 2 (PO 4 ) 3 Materials intercalate lithium to obtain Li 3+x V 2 (PO 4 ) 3 (1≤x≤2);

[0023] (3) Under the -40 degree dew point environment, assemble the positive electrode sheet obtained in step (2) and the SiO / C composite negative electrode sheet with a gram capacity of 650mAh / g that meets the full battery design to form a full battery. At room temperature, charge and discharge f...

Embodiment 3

[0025] (1) Weigh Li according to 3% of the LFP mass in the material ratio of the positive pole piece. 3 V 2 (PO 4 ) 3 The material is added to the positive electrode material, and the positive electrode sheet is made according to the normal mixing, coating, rolling, and cutting processes;

[0026] (2) The positive electrode sheet obtained in step (1) is discharged with metallic lithium as the counter electrode, the lower limit of the control voltage is 1.2V, the active lithium of the negative electrode is inserted into the positive electrode, and the Li in the positive electrode sheet 3 V 2 (PO 4 ) 3 Materials intercalate lithium to obtain Li 3+x V 2 (PO 4 ) 3 (1≤x≤2);

[0027](3) Under the -40 degree dew point environment, assemble the positive pole piece obtained in step (2) and the negative pole piece of hard carbon negative electrode material with a gram capacity of 400mAh / g that satisfies the design of the full battery to form a full battery. At room temperatu...

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Abstract

The invention discloses a technical method for improving the primary efficiency of a lithium-ion full battery. Add Li to the positive active material in a certain proportion 3 V 2 (PO 4 ) 3 , the obtained positive electrode sheet is discharged with metal lithium as the counter electrode, and the lower limit of the control voltage is 1.2V, so that Li 3 V 2 (PO 4 ) 3 Materials intercalate lithium to obtain Li 3+x V 2 (PO 4 ) 3 (1≤x≤2). The above-mentioned positive electrode sheet in the empty state and the negative electrode with low first efficiency are combined to form a full battery, and the charging and discharging voltage range is controlled. The first charging process makes Li 3+x V 2 (PO 4 ) 3 Extract x units of active lithium and intercalate into the negative electrode, and the lower limit of the discharge control voltage is above 2V so that x units of active lithium are no longer intercalated in the positive electrode, which can compensate for the loss of active lithium in the side reaction of the negative electrode during the first charge, thereby improving the initial performance of the lithium-ion full battery. effective, and Li 3 V 2 (PO 4 ) 3 It has electrochemical activity in the normal full battery charge and discharge range, and does not affect the capacity of the positive electrode material. This technical method effectively improves the first-time efficiency and cycle performance of lithium-ion full batteries.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a technical method for improving the primary efficiency of lithium-ion full batteries. [0002] technical background [0003] As a green new energy technology, lithium-ion battery has very important and broad application prospects. With the wide application of lithium-ion batteries, the market has put forward higher demands. At the end of 2015, in the "13th Five-Year" new energy vehicle pilot special project issued by the Ministry of Science and Technology, it is required that by 2020, the specific energy of lithium-ion power batteries in my country will reach 300Wh / kg, and even 350Wh / kg. At present, a new generation of high specific energy lithium-ion batteries is a research hotspot. The requirement of high energy density requires the use of high specific capacity anode materials or composite materials of high capacity anodes and traditional graphite a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/62H01M10/058H01M10/0525
CPCY02E60/10Y02P70/50
Inventor 杨茂萍杨尘
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY