Method for measuring wettability of lithium battery electrolyte or lithium ion battery electrolyte on battery material

A lithium-ion battery and electrolyte technology, which is applied to the accurate measurement of the wettability of the negative electrode and diaphragm, and the field of measuring the electrolyte to the positive electrode of the battery. It can solve the problem of not clearly describing the specific steps of the test, the contact angle test conditions and parameters, and the inability to simulate electrolysis. Eliminate the problems of liquid infiltration process on the positive and negative electrodes, low accuracy, etc., to achieve the effect of optimizing the static process of the battery, accurate and reliable measurement results, and easy operation

Inactive Publication Date: 2013-01-09
BEIJING INST OF CHEM REAGENTS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The commonly used measuring method has to judge the wettability of the electrolyte by measuring the viscosity of the electrolyte. In the Chinese patent (publication number CN101009392A), the wettability of the electrolyte to the battery in the battery after the liquid injection is observed by visual inspection; Influence of magnesium deposition-dissolution performance in BMImBF4 ionic liquid electrolyte, Nu Liyanna, Acta Cheminica Sinica, 2010, 68 (10): 948-954), by measuring the liquid absorption and liquid retention of the material to the electrolyte Infer the wettability of the electrolyte to the material, soak the material in the electrolyte, and use the weighing method to calculate the percentage difference of the weight of the material before and after soaking; the above method judges the wettability of the electrolyte by indirect judgment, visual inspection or timing. The error is large, the accuracy is low, and because the positive and negative materials tested are not added with conductive agents, binders and other components in the powder state, it cannot simulate the infiltration process of the positive and negative electrodes by the electrolyte inside the real battery
In the Chinese patent (publication number CN101615697A), the contact angle measuring instrument is only used to measure the contact angle of the diaphragm, and the specific steps of the test and the contact angle test conditions and parameters are not clearly described in the patent
Patents in this area have not been reported

Method used

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  • Method for measuring wettability of lithium battery electrolyte or lithium ion battery electrolyte on battery material
  • Method for measuring wettability of lithium battery electrolyte or lithium ion battery electrolyte on battery material
  • Method for measuring wettability of lithium battery electrolyte or lithium ion battery electrolyte on battery material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] LiFePO 4 Preparation of positive electrode substrate: active material LiFePO 4 The content of carbon black is 95%, carbon black is 3.0%, and binder PVDF2.0% is evenly mixed, and the prepared slurry is evenly coated on the aluminum current collector, flattened and sliced ​​on a double-roller machine, and the flat pole piece will be prepared Vacuum-dried at 110° C. for 14 hours to obtain the substrate to be tested.

[0032] The electrolyte to be tested is: ethylene carbonate 26.4%, diethyl carbonate 24.2%, propylene carbonate 35.9%, LiPF 6 12.5%, vinylene carbonate 1%.

[0033] Wettability measurement: Place the positive electrode substrate flat on the platform, drop 5 μL of liquid droplets with a micro-sampler at 25°C, the height of the droplet falling and the test substrate is 0.2cm, and set the shooting speed of the contact angle measuring instrument to 40 frames / s, continuous shooting, with a magnification of 30 times, and analyze the photos taken of the droplet f...

Embodiment 2

[0036] The test substrate of the tested electrolyte is: polypropylene diaphragm.

[0037] The electrolyte to be tested is: 26% ethylene carbonate, 24% diethyl carbonate, 20% ethyl methyl carbonate, 14% ethyl acetate, LiPF 6 15%, vinylene carbonate 1%.

[0038] The measurement method is as the measurement of wettability in Example 1. The diaphragm is placed flat on the platform. At 25°C, a 7 μL droplet is dropped with a micro-sampler. The height between the droplet and the test substrate is 0.2cm. Set the shooting speed to 50 frames / s, shoot continuously, and the magnification factor is 30 times. Analyze the photos of the falling droplets and use the half-angle method for analysis. The θ1 when recording 0.05s is 49°4′, greater than 20 °, the shooting speed remains unchanged, 0.1s of θ0.1s is 48°6′; θ0 is 51°7′, θ2s is 43°2′, and the infiltration speed τ in the first 2s is calculated according to the formula to be 4.3° / s.

Embodiment 3

[0040] The test substrate and determination method are the same as in Example 2, only the electrolyte is different from Example 2.

[0041] The electrolyte to be tested is: 26% ethylene carbonate, 24% diethyl carbonate, 20% ethyl methyl carbonate, 14% ethyl propionate, LiPF 6 15%, vinylene carbonate 1%.

[0042] The wettability result obtained is that θ1 at 0.05s is 51°4′, using the shooting speed parameters of Example 2, θ0.1s at 0.1s is 48°9′, θ0s is 51°3′, and θ2s is 45°2′ , according to the formula, the infiltration velocity τ in the first 2s is 3.1° / s.

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Abstract

The invention relates to a method for measuring wettability of lithium battery electrolyte or lithium ion battery electrolyte on a battery material, and the battery standing time is optimized according to the experimental results. Simultaneously, the precise measuring methods with the different degrees of wettability are distinguished. The invention provides a method for measuring electrolyte wettability at low temperature, so that the method provided by the invention is convenient and fast, the detected result accuracy is high, and the wettability of the electrolyte on the battery material is comprehensively and effectively evaluated, the battery standing technology is optimized according to the wetting speed, and the preparation efficiency of the batteries is improved.

Description

technical field [0001] The invention relates to a lithium or lithium ion battery electrolyte analysis method, in particular to an accurate measurement method for measuring the wettability of the electrolyte to the positive electrode, the negative electrode and the diaphragm of the battery at room temperature and low temperature. Background technique [0002] In recent years, due to the pressure of energy shortage, all countries are trying to find new energy sources. As an excellent energy storage device, the battery has been widely used in military aerospace, energy storage power supply, electric vehicles and other fields due to its high energy density and long life. [0003] The electrolyte plays the role of transporting ions between the positive and negative electrodes of the battery, and plays the role of blood in the battery. However, when the electrolyte is under certain conditions such as low temperature conditions, the physical and chemical properties of the electrol...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N13/00
Inventor 李冰川
Owner BEIJING INST OF CHEM REAGENTS
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