Negative electrode pole piece and secondary battery
A technology of negative pole piece and negative film piece, applied in the field of negative pole piece and secondary battery, can solve the problems of battery heating, affecting the safety of end consumers, and the battery energy density can not meet the requirements, and achieve long cycle life, The effect of high energy density, fast charging capability
Active Publication Date: 2019-03-12
CONTEMPORARY AMPEREX TECH CO
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AI Technical Summary
Problems solved by technology
In the design of the negative electrode sheet, in order to achieve high energy density of the battery, the coating weight of the active material per unit area of the current collector is usually increased, but at this time the charging capacity of the battery often cannot meet the requirements; and when in order to meet the charging capacity of the battery However, when the coating weight of the active material per unit area of the current collector is reduced, the energy density of the battery cannot meet the requirements.
In addition, the battery has serious heating problems during fast charging, which will also affect the safety of end consumers.
Method used
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Embodiment 1
[0045] (1) Preparation of positive pole piece
[0046] Mix the positive electrode active material (see Table 1 for details), conductive agent Super P, and binder polyvinylidene fluoride (PVDF) at a mass ratio of 96:2:2, add solvent N-methylpyrrolidone (NMP), and vacuum Stir under the action of a mixer until the system is uniform to obtain the positive electrode slurry; evenly coat the positive electrode slurry on the aluminum foil of the positive electrode current collector, dry at room temperature, transfer to an oven to continue drying, and then cold press and cut to obtain the positive electrode sheet .
[0047] (2) Preparation of negative pole piece
[0048] After mixing the negative electrode active material (see Table 1 for details), conductive agent Super P, thickener sodium carboxymethylcellulose (CMC), and binder styrene-butadiene rubber (SBR) in a mass ratio of 96.4:1:1.2:1.4 , add solvent deionized water, stir under the action of a vacuum mixer until the system is...
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Abstract
The invention provides a negative electrode pole piece and a secondary battery. The negative electrode pole piece comprises a negative electrode current collector and a negative electrode diaphragm which is arranged on at least one surface of the negative electrode current collector and comprises negative electrode active substances. The negative electrode pole piece meets the following conditionsthat Vp / Sp is greater than or equal to 0.05 and less than or equal to 0.30, Vp is equal to the thickness T of the negative electrode diaphragm*the porosity P of the negative electrode diaphragm, andSp is equal to the mass M of negative electrode active substances in the negative electrode diaphragm of a unit area*the specific surface area BET (Brunauer, Emmett and Teller) of the negative electrode diaphragm. By use of the negative electrode pole piece, a relationship between pore passage occupation volume in the negative electrode diaphragm of the unit area and a pore passage surface area inthe negative electrode diaphragm is matched to obtain a secondary battery which combines the characteristics of long cycle life, high energy density and quick charging capability.
Description
technical field [0001] The invention relates to the field of batteries, in particular to a negative pole piece and a secondary battery. Background technique [0002] Rechargeable batteries have outstanding features such as light weight, high energy density, no pollution, no memory effect, and long service life, so they are widely used in mobile phones, computers, household appliances, power tools and other fields. Among them, charging time is increasingly valued by end consumers, and it is also an important factor limiting the popularity of rechargeable batteries. [0003] From the technical principle, the key to determine the charging speed of the battery is the negative electrode. In the design of the negative electrode sheet, in order to achieve high energy density of the battery, the coating weight of the active material per unit area of the current collector is usually increased, but at this time the charging capacity of the battery often cannot meet the requirements...
Claims
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IPC IPC(8): H01M4/131H01M4/133H01M4/134H01M10/0525H01M10/054
CPCH01M4/131H01M4/133H01M4/134H01M10/0525H01M10/054H01M4/505H01M4/525H01M4/587H01M2004/021H01M2004/027H01M2220/30Y02E60/10H01M4/80
Inventor 王家政申玉良康蒙何立兵
Owner CONTEMPORARY AMPEREX TECH CO