CN106353352B - Method for detecting dispersion effect of carbon material in lead-acid storage battery - Google Patents

Abstract

the invention relates to the technical field of detection of distribution condition of an additive in a solid substance. A method for detecting the dispersion effect of a carbon material in a lead-acid storage battery is characterized in that the dispersion effect of the carbon material in lead paste is observed in a mode of combining an electron microscope energy spectrum element picture before a polar plate is processed with a polar plate electron microscope picture after the polar plate is processed, and the expression form influencing the dispersion effect of the carbon material is found to be the particle size and the distribution uniformity of an active substance after the processing; the technical problems that the time for detecting the dispersion effect of the carbon material is long, the accuracy of detection is high and direct observation and judgment cannot be achieved in the prior art are solved.

Description

A method for detecting the dispersion effect of carbon materials in lead-acid batteries

technical field

The invention relates to the technical field of detecting the distribution of additives in solid matter, in particular to a method for detecting the dispersion effect of carbon materials in lead-acid batteries.

Background technique

Lead-acid batteries have a history of 130 years. They have the advantages of reliable performance, mature production technology, and lower cost than nickel-metal hydride batteries and lithium batteries. The vast majority of current electric bicycles use sealed lead-acid batteries. The sealed lead-acid battery is to stack the positive and negative plates in the battery box, and the positive and negative plates are separated by insulating separators. When the electrolyte is charged into the battery box, the electrolyte and the positive and negative plates lead chemical reaction. When the battery is charged, the lead on the positive and negative plates that become lead sulfate releases the sulfuric acid component fixed in it into the electrolyte, and turns into lead and lead oxide respectively, so that the concentration of sulfuric acid in the electrolyte increases continuously, and the voltage When discharging, the lead oxide in the positive plate and the lead in the negative plate react with the sulfuric acid in the electrolyte to become lead sulfate, so that the concentration of sulfuric acid in the electrolyte decreases continuously, the voltage drops, and the energy decreases. The battery outputs energy externally, so the cycle charge and discharge of the battery is a process of continuous conversion of electrical energy and chemical energy, and finally realizes the storage and release of energy.

Valve-regulated lead-acid batteries are widely used in electric vehicles due to their cheapness, safety, and no need to replenish electrolyte. Batteries generally need to be connected in series to be used in groups. The overall performance of the battery pack depends on the worst performance of the whole battery pack. Early failure and short life, so the consistency of the battery needs to be improved to ensure the performance and life of the entire battery pack. The dispersion of additives inside the battery directly affects the overall performance of the battery. For example, the Chinese patent: "A lead-acid battery negative electrode additive and its preparation method (CN104022287A)", the additive is a layered carbon/lead oxide composite material, and the number of layers of the layered carbon is 1-50 layers. The lead particles are evenly attached to the layered carbon, the size of the lead oxide particles is 5-200nm, and the mass ratio of the layered carbon to the lead oxide is 1:1-200.

With the development of research and development technology, product quality requirements are becoming more and more stringent. It is also an important way to improve battery performance by improving the dispersion of additives inside the battery. The better the dispersion of additives, the more stable the performance of lead-acid batteries, which puts forward higher requirements for the accuracy, convenience and efficiency of the dispersion inspection and dispersion detection of carbon materials inside the battery.

At present, the detection of the dispersion effect of carbon materials in lead-acid batteries mainly adopts methods such as metallographic microscope observation or indirect display of data measured by roughness testers, and the use of such methods to detect the dispersion effect of carbon materials has a long inspection time and detection The accuracy is low and it cannot intuitively reflect the dispersion effect of carbon materials in the lead paste.

Contents of the invention

The invention provides an effective, fast, accurate and intuitive test method for observing the dispersion effect of carbon materials in lead paste; it solves the problem of long time for detecting the dispersion effect of carbon materials in the prior art. Accuracy is the first, technical problems that cannot be directly observed and judged.

Above-mentioned technical problem of the present invention is solved by following technical scheme: a kind of detection method of carbon material dispersion effect in lead-acid storage battery, it is characterized in that: comprise the following steps:

Step 1: Add carbon material as negative electrode additive to lead powder, and mix with lead powder evenly to obtain mixed lead paste;

Step 2: Assemble the cooked plate coated with mixed lead paste into a battery, and then discharge it. After the discharge is complete, dry the cooked plate to prepare a sample to be inspected, and put the sample to be inspected into the sample room of the scanning electron microscope for observation , scan and take a picture of the sample, start the energy spectrometer to analyze the elements of the test sample, and obtain the carbon element distribution spectrum;

The third step: after the electron microscope test, the intact sample is treated with chemical reagents to the lead sulfate particles, and the undissolved active substance sample is dried and then observed under the scanning electron microscope, and the scanning parameters of the scanning electron microscope are adjusted. Take pictures of samples;

Step 4: Analyze the distribution of carbon materials by combining the scanning energy spectrum element distribution diagram of the active material sample with the processed scanning electron microscope diagram.

Combining the electron microscope energy spectrum element map before the plate treatment and the plate electron microscope picture after treatment to observe the dispersion effect of the carbon material in the lead paste, it is found that the expression form that affects the dispersion effect of the carbon material is the post-treatment Active material particle size and distribution uniformity, when the apparent size of the active material particles is large and the distribution is uneven, it indicates that the distribution of carbon materials is less and uneven within this range; when the apparent size of the active material particles is smaller and the distribution within the range Uniform, indicating that the distribution of carbon materials in this range is relatively sufficient and evenly dispersed.

Preferably, in the first step, the amount of carbon material added to the lead powder is 0.1-2% of the weight of the lead powder.

Preferably, in the first step, the carbon material is uniformly mixed with the lead powder by oscillating and stirring, the oscillating and stirring speed is 120-240 r/min, and the stirring time is 10-20 minutes.

As a preference, in the second step, a high-magnification lens is used in the electron microscope scanning process, the acceleration voltage value is 10kv~30kv, and the working focal length is 12~25mm.

As a preference, when the undissolved active substance is scanned again with an electron microscope in the third step, a low magnification lens is used for scanning, the acceleration voltage is 3kv~10kv, and the working focal length is 5~15mm. The chemical reagent in the described third step is sodium acetate solution or nitric acid and hydrogen peroxide reagent. In the third step, the sample treated with chemical reagents is used to collect element distribution by surface scanning.

Preferably, the carbon material in the first step is one or more of activated carbon, acetylene black, graphene, carbon nanotubes, and carbon black.

Therefore, the detection method of a kind of carbon material dispersion effect in lead-acid storage battery of the present invention has the following advantages:

1. The present invention uses a scanning electron microscope energy spectrum to collect elements to collect the distribution of carbon elements in the plate, and at the same time combine the particle size and distribution uniformity of lead sulfate in the processed plate to determine the carbon material in the lead plate. The dispersion effect in the paste can quickly, intuitively and accurately characterize the dispersion of carbon materials. The combination of elemental distribution collected by energy spectrum and post-discharge treatment of the lead sulfate particle size and distribution uniformity of the determination method is simple to operate and clear to shoot. Electron microscope images and energy spectrum element distribution can visually observe the dispersion effect of carbon materials. Type form, so as to draw an accurate judgment.

2. The present invention can quickly and intuitively judge the overall dispersibility of carbon materials, and compare samples prepared under different process conditions in parallel to find out the cause of poor dispersibility, so as to guide production and facilitate targeted Improve the production process.

Description of drawings

FIG. 1 is an energy spectrum diagram of the carbon element distribution effect of the untreated plate sample in Example 1.

Fig. 2 is an electron microscope scanning image of the untreated plate sample in Fig. 1 .

FIG. 3 is an electron microscope scanning image of the electrode plate sample treated with chemical reagents in FIG. 1 .

Fig. 4 is an energy spectrogram of the carbon element distribution effect of the untreated plate sample in Example 2.

Fig. 5 is an electron microscope scanning image of the untreated plate sample in Fig. 2 .

FIG. 6 is an electron microscope scanning image of the plate sample in FIG. 2 after being treated with chemical reagents.

Detailed ways

The technical solution of the invention will be further specifically described below through the embodiments and in conjunction with the accompanying drawings.

Example 1:

A method for detecting the dispersion effect of carbon materials in lead-acid batteries, the method has the following steps:

In the first step, take 10 grams of carbon black and add it to 10 kilograms of lead powder, and stir it at a constant speed for 15 minutes by means of oscillating stirring, at a stirring rate of 180 R/min, and obtain a mixed lead paste after mixing evenly;

In the second step, the battery assembled with the cooked plate coated with the above mixed lead paste is connected to the circuit and fully discharged to the battery voltage ≦ 1.8v/cell, and the cooked plate is taken out and washed and dried to prepare a 2*2*0.5cm active substance samples. Put the active material sample together with the glass slide into the sample chamber of the scanning electron microscope, and adjust the parameters of the scanning electron microscope: use a high-magnification lens, an accelerating voltage of 20kv, a working focal length of 20mm, and a parameter setting of magnification × 1000. The electronic scanning parameters are consistent, the mode is surface scanning, and the number of scanning frames is 64 frames. Obtain its carbon element distribution energy spectrum (as shown in Figure 1) and electron microscope scanning diagram (as shown in Figure 2);

The third step is to use sodium acetate solution to treat the sample that has been tested and preserve the complete energy spectrum. The large particles of lead sulfate contained on the sample, the undissolved active substance sample is dried and then observed under the scanning electron microscope, and the scanning electron microscope is adjusted. Scanning parameters: use a low-magnification lens, an accelerating voltage of 5kv, a working focal length of 5mm, and a magnification of ×1000 to take an electron microscope scan of the sample (as shown in Figure 3);

The fourth step is to analyze the carbon material distribution by combining the scanning energy spectrum element distribution map of the active material sample and the processed scanning electron microscope image, observe the dispersion effect of the carbon material and related surface characteristics, and obtain an accurate carbon material dispersion data.

Example 2:

A method for detecting the dispersion effect of carbon materials in lead-acid batteries, the method has the following steps:

In the first step, take a mixture of 70 grams of activated carbon and 30 grams of acetylene black and add it to 10 kilograms of lead powder, and stir it at a constant speed for 18 minutes by means of oscillating stirring at a stirring rate of 220 R/min. After mixing evenly, a mixed lead paste is obtained;

In the second step, the battery assembled with the cooked plate coated with the above-mentioned mixed lead paste is connected to the line and fully discharged to the battery voltage ≦ 1.8v/cell, and the cooked plate is taken out and washed and dried to prepare a size of 1.5*1.5*0.8cm active substance samples. Put the active material sample together with the glass slide into the sample chamber of the scanning electron microscope, and adjust the parameters of the scanning electron microscope: high-magnification lens, accelerating voltage of 25kv, working focal length of 25mm, parameter setting of magnification ×1000, energy spectrum scanning parameters and The electronic scanning parameters are consistent, the mode is surface scanning, and the number of scanning frames is 64 frames. Obtain its carbon element distribution energy spectrum (as shown in Figure 4) and electron microscope scanning diagram (as shown in Figure 5);

The third step is to use sodium acetate solution to treat the sample that has been tested and preserve the complete energy spectrum. The large particles of lead sulfate contained on the sample, the undissolved active substance sample is dried and then observed under the scanning electron microscope, and the scanning electron microscope is adjusted. Scanning parameters: use a low-magnification lens, an accelerating voltage of 8kv, a working focal length of 10mm, and a magnification of x1000 to take an electron microscope scan of the sample (as shown in Figure 6);

The fourth step is to analyze the carbon material distribution by combining the scanning energy spectrum element distribution map of the active material sample and the processed scanning electron microscope image, observe the dispersion effect of the carbon material and related surface characteristics, and obtain an accurate carbon material dispersion data.

The embodiment described above is only a preferred solution of the present invention, and does not limit the present invention in any form, and there are other variations and modifications on the premise of not exceeding the technical solution described in the claims.

Claims (5)

1. a method for detecting the dispersion effect of a carbon material in a lead-acid storage battery is characterized by comprising the following steps: the method comprises the following steps:

The first step is as follows: adding a carbon material serving as a negative electrode additive into lead powder, and uniformly mixing the carbon material with the lead powder to obtain mixed lead paste;

The second step is that: assembling the cooked polar plate coated with the mixed lead plaster into a battery, then discharging, drying the cooked polar plate after complete discharge to prepare a sample to be detected, putting the sample to be detected into a sample chamber of a scanning electron microscope for observation, scanning and shooting a sample picture, starting an energy spectrum tester to perform element analysis on the test sample, and obtaining a carbon element distribution spectrogram;

The third step: treating the lead sulfate particles in a sample which is completely stored after the electron microscope test by using a chemical reagent to dissolve the lead sulfate particles, drying the undissolved sample, observing under a scanning electron microscope again, adjusting scanning parameters of the scanning electron microscope, and taking a picture of the sample;

The fourth step: analyzing the distribution condition of the carbon material by combining a scanning energy spectrum element distribution diagram of a sample to be detected with a scanning electron microscope diagram of an undissolved sample treated by a chemical reagent;

In the second step, a high power lens is adopted for scanning in the scanning process of the electron microscope, the accelerating voltage value is 10-30 kv, and the working focal length is 12-25 mm;

When the undissolved sample is scanned by the electron microscope again in the third step, a low-power lens is adopted for scanning, the accelerating voltage value is 3-10 kv, and the working focal length is 5-15 mm;

And in the third step, the element distribution of the sample treated by the chemical reagent is collected in a surface scanning mode.

2. The method for detecting the dispersion effect of the carbon material in the lead-acid storage battery according to claim 1, wherein the method comprises the following steps: in the first step, the adding amount of the carbon material in the lead powder is 0.1-2% of the weight of the lead powder.

3. The method for detecting the dispersion effect of the carbon material in the lead-acid storage battery according to claim 1 or 2, wherein: in the first step, the carbon material is uniformly mixed with the lead powder in a vibration stirring mode, the vibration stirring speed is 120-240 r/min, and the stirring time is 10-20 minutes.

4. The method for detecting the dispersion effect of the carbon material in the lead-acid storage battery according to claim 1 or 2, wherein: and the chemical reagent in the third step is sodium acetate solution or a mixed reagent of nitric acid and hydrogen peroxide.

5. the method for detecting the dispersion effect of the carbon material in the lead-acid storage battery according to claim 1 or 2, wherein: the carbon material in the first step is one or more of activated carbon, acetylene black, graphene, carbon nano tubes and carbon black.