阅读说明：本技术 一种判定余酸是否抽尽的方法 (Method for judging whether spent acid is completely extracted ) 是由 刘玉 李桂发 田庆山 张峰博 施璐 周贤机 邓成智 李靖 郭志刚 张天任 高银 于 2020-10-12 设计创作，主要内容包括：本发明公开了一种判定余酸是否抽尽的方法,包括：(1)准备顶部设有压力传感器的测试胶帽,测试胶帽扣在电池加酸口上时的开阀压力不低于50kPa；(2)在内化成末期,电池充电2～4h后,在充电状态下抽酸；(3)抽酸结束后停止充电,进行第一次静置；(4)盖上测试胶帽,进行第二次静置；(5)打开充电机继续充电,计算充入电量,并进一步计算当充电产生的气体完全进入气室时的理论压强P；(6)充电结束后,将压力传感器测得的压力转换成实际压强P_1后与理论压强P进行比较：若实际压强P_1很快可以达到理论压强P时,判定余酸未被抽干净；若实际压强P_1一直无法达到理论压强P时,判定余酸已被抽干净。利用本发明,可以对电池单格余酸进行有效判定。(The invention discloses a method for judging whether spent acid is completely extracted, which comprises the following steps: (1) preparing a testing rubber cap with a pressure sensor at the top, wherein the valve opening pressure of the testing rubber cap is not lower than 50kPa when the testing rubber cap is buckled on an acid adding port of a battery; (2) in the final internal formation stage, after the battery is charged for 2-4 hours, acid is pumped out in a charging state; (3) stopping charging after acid pumping is finished, and standing for the first time; (4) covering a test rubber cap, and standing for the second time; (5) opening a charger to continue charging, calculating the charging amount, and further calculating the theoretical pressure P when the gas generated by charging completely enters the gas chamber; (6) after charging is finished, converting the pressure measured by the pressure sensor into actual pressure P 1 And then comparing with the theoretical pressure P: if the actual pressure P 1 When the theoretical pressure P can be reached quickly, the residual acid is judged not to be pumped completely; if the actual pressure P 1 And when the theoretical pressure P can not be reached all the time, judging that the residual acid is completely pumped. By using the invention, the battery cell spent acid can be treatedAnd (6) judging effectively.)

1. A method for judging whether spent acid is completely extracted is characterized by comprising the following steps:

(1) preparing a testing rubber cap with the same size as the battery safety valve, wherein the top of the testing rubber cap is provided with a pressure sensor, and the valve opening pressure of the testing rubber cap is not lower than 50kPa when the testing rubber cap is buckled on an acid adding opening of a battery;

(2) in the final stage of the container formation of the storage battery, the battery is in a full-charge state, after charging for 2-4 hours, acid is extracted in the charging state, and residual acid is extracted;

(3) stopping charging after acid pumping is finished, and standing for the first time;

(4) after the standing is finished, covering a test rubber cap, and standing for the second time;

(5) turning on a charger and continuing to charge; calculating the charged electric quantity according to the charging time and the charging current, and further calculating the theoretical pressure P when the gas generated by charging completely enters the gas chamber;

(6) after charging is finished, converting the pressure measured by the pressure sensor into actual pressure P₁And then comparing with the theoretical pressure P:

if the actual pressure P₁When the theoretical pressure P can be reached quickly, the saturation degree of the partition plate is judged to be higher, and the residual acid is not completely pumped;

if the actual pressure P₁And when the theoretical pressure P can not be reached all the time, judging that an oxygen channel exists on the partition plate and the residual acid is completely pumped.

2. The method for determining exhaustion of residual acid according to claim 1, wherein the charging current in the charging and acid-extracting process in step (2) is 0.01C₂～0.1C₂。

3. The method for determining residual acid exhaustion according to claim 1, wherein in the step (2), the charging process is performed by constant current charging.

4. The method for determining whether or not spent acid is exhausted according to claim 1, wherein the standing time in the step (3) is 30 to 60 min.

5. The method for determining whether or not spent acid is exhausted according to claim 1, wherein the time for the second standing in the step (4) is 5 to 10 min.

6. The method for determining depletion of residual acid according to claim 1, wherein said method comprisesIn the step (5), the charging current is 0.005C₂～0.01C₂。

7. The method for determining residual acid exhaustion according to claim 1, wherein in the step (5), the calculation process of the theoretical pressure P is specifically as follows:

according to the charge reaction formula H₂O→2H⁺+1/2O₂+2e^-Generating 2mol electrons while generating 0.5mol oxygen; electric quantity Q of 2mol electrons is 2 × 9.632 × 10⁴＝19.264×10⁴C；

Charging 1Ah of electricity according to the condition that 1Ah is 3600C to obtain 0.0186mol of electrons, wherein the oxygen generation amount is 0.0046 mol; the charging quantity is obtained by multiplying the charging time and the charging current, and when the charging quantity is X Ah, the corresponding oxygen generation quantity is 0.0046X mol;

calculating to obtain theoretical pressure P according to an ideal gas state equation PV ═ nRT; where V represents the volume of the gas chamber inside the cell, n represents the amount of gaseous material, T represents the absolute temperature, and R represents the gas constant.

8. The method of claim 7, wherein the charging amount and the theoretical pressure are constant after the charging process is fixed for the same batch of batteries.

Technical Field

The invention belongs to the technical field of storage battery production, and particularly relates to a method for judging whether formed spent acid in a storage battery is completely extracted.

Background

In the battery formation process of the sealed valve-controlled lead-acid battery, in order to ensure that the battery can smoothly complete active substance conversion, excessive electrolyte is added. In the whole formation process, the polar plate is in a liquid-rich state, after formation is finished, all the electrolyte is required to be stored in the AGM separator, and the flowing electrolyte is pumped out in the final formation stage, so that the saturation of the separator is reduced, and a gas channel is reserved for oxygen recombination. During the use of the battery, in the later stage of charging, oxygen generated by the positive electrode can be transmitted to the negative electrode through the gas channel, and oxygen recombination is completed at the negative electrode, so that the loss of water in the storage battery is reduced, and the purpose of being free of maintenance is achieved.

If the redundant electrolyte can not be pumped out, the flowing electrolyte is stored at the upper part of the pole group, the AGM partition plate is in an oversaturated state, and the performance of the battery can be obviously influenced, particularly, the power battery for deep circulation use has no effective gas channel, the gas generated by charging can be rarely transmitted to a negative electrode, but is emitted along the height direction of the pole plate, and is finally stored in a gas chamber in the battery. Although the saturation degree of the separator can be improved by the loss of water, the density of the electrolyte is actually higher than the designed value at the moment, and the service performance of the battery is reduced.

Particularly, the 12V battery is formed by connecting 6 2V cells in series, wherein one cell can influence the service performance of the whole battery because the spent acid is not completely pumped out. In the existing battery production process, a vacuum pump is connected with an acid pumping pipe, and in the acid pumping stage, the acid pumping pipe is inserted into an acid adding hole of a battery to pump residual acid.

For example, chinese patent publication No. CN206313034U discloses an acid pumping device, which includes a moving platform, and a sulfuric acid filtering barrel, a sulfuric acid storage tank, a buffer tank, a glass condenser, a condensed water tank, and a vacuum pump, which are disposed on the moving platform.

Chinese patent publication No. CN207134421U discloses a formation workshop acid pumping device, which comprises an acid pumping tank, a protective tank and a vacuum pump, wherein the top end of the acid pumping tank is communicated with the lower part of the protective tank, the acid pumping tank is communicated with an acid pumping pipe, the top end of the protective tank is communicated with the vacuum pump, an acid gas filtering device is arranged between the protective tank and the vacuum pump, and a liquid level display device is arranged on the side wall of the acid pumping tank and the protective tank.

However, the temperature of the environment and the operation method of workers may cause incomplete pumping of the residual acid, which is easy to cause unit differences. In order to effectively control the quality, production enterprises require secondary acid extraction, and some production enterprises also require production personnel to check each single cell by using a flashlight.

Disclosure of Invention

The invention provides a method for judging whether spent acid is completely extracted, which can effectively judge the spent acid of a single cell of a battery, and then perform secondary acid extraction on cells which are not completely extracted, so that the difference among the cells is reduced, and the production quality of the battery is ensured.

A method for judging whether spent acid is exhausted comprises the following steps:

(1) preparing a testing rubber cap with the same size as the battery safety valve, wherein the top of the testing rubber cap is provided with a pressure sensor, and the valve opening pressure of the testing rubber cap is not lower than 50kPa when the testing rubber cap is buckled on an acid adding opening of a battery;

(2) in the final stage of the container formation of the storage battery, the battery is in a full-charge state, after charging for 2-4 hours, acid is extracted in the charging state, and residual acid is extracted;

(3) stopping charging after acid pumping is finished, and standing for the first time;

(4) after the standing is finished, covering a test rubber cap, and standing for the second time;

(5) turning on a charger and continuing to charge; calculating the charged electric quantity according to the charging time and the charging current, and further calculating the theoretical pressure P when the gas generated by charging completely enters the gas chamber;

(6) after charging is finished, converting the pressure measured by the pressure sensor into actual pressure P₁And then comparing with the theoretical pressure P:

if the actual pressure P₁When the theoretical pressure P can be reached quickly, the saturation degree of the partition plate is judged to be higher, and the residual acid is not completely pumped;

if the actual pressure P₁And when the theoretical pressure P can not be reached all the time, judging that an oxygen channel exists on the partition plate and the residual acid is completely pumped.

The principle of the invention is as follows:

after the formation of the sealed valve-controlled lead-acid battery is finished, the saturation of the AGM separator is controlled to be about 94% ideally, at the moment, about 6% of pores are formed in the separator, the part of pores are gas transmission channels, oxygen is generated by a positive electrode side reaction under the state that the battery is fully charged, the oxygen can be transmitted to a negative electrode through the gas channels in the pores of the separator, at the moment, the negative electrode is very active spongy metal lead, and the lead is easily oxidized after contacting with the oxygen, so that oxygen recombination is realized.

After the formation of the battery is finished, if residual acid is not extracted completely, free electrolyte exists in the battery, the saturation degree of the partition plate is 100%, no gas pore is formed, gas generated by the anode cannot be transmitted to the cathode, and the gas can be released into a gas chamber in the battery only along the height direction of the polar plate to form gas pressure on a test rubber cap; according to the pressure sensor on the test rubber cap, whether the residual acid is completely pumped can be determined through calculation.

Preferably, in the step (2), the charging current in the charging and acid extracting process is 0.01C₂～0.1C₂(ii) a The charging process adopts constant current charging.

In the step (3), the standing time is 30-60 min. Before the extraction of the residual acid is finished, the battery is always in a charged state, the temperature inside the battery is higher, after the power failure, the residual temperature is maintained, if the testing rubber cap is covered at the moment, the volume is larger than the normal temperature probably because the gas inside is influenced by thermal expansion, and therefore the measurement at the moment can possibly cause misjudgment, and the stage of cooling through standing is required.

Preferably, in the step (4), the time for the second standing is 5min to 10 min. Through the standing for a short time, the gas in the internal pole group and the gas chamber forms a temporary stable state, so that the accuracy of later-period data acquisition is facilitated.

Further, in the step (5), the charging current is 0.005C₂～0.01C₂。

If the set current is too large, part of the unit spent acid is completely pumped, but the saturation is relatively high, namely the pores of the partition plate are few, all generated gas cannot be compounded in time, most of the gas can be discharged into the gas chamber, and the larger the current is, the more the gas in the gas chamber is, and the unit misjudgment can be caused at the moment.

And small current is set for charging, the positive electrode and the negative electrode are charged at the moment, the positive electrode can continuously generate side reaction due to the small current, oxygen is continuously generated, and the generated gas is less because of the small current, so that oxygen recombination can be completed because of less gas generation even if the residual acid is completely pumped out and the single cells with relatively high saturation are completely. And setting a small current for charging, if the residual acid is not completely pumped out, the saturation degree of the partition plate reaches 100%, and no gas channel exists, the generated gas can be only stored in the gas chamber, and the gas pressure in the gas chamber is gradually increased because the test rubber cap is covered.

In the step (5), the calculation process of the theoretical pressure P specifically includes:

according to the charge reaction formula H₂O→2H⁺+1/2O₂+2e^-Generating 2mol electrons while generating 0.5mol oxygen; electric quantity Q of 2mol electrons is 2 × 9.632 × 10⁴＝19.264×10⁴C；

Charging 1Ah of electricity according to the condition that 1Ah is 3600C to obtain 0.0186mol of electrons, wherein the oxygen generation amount is 0.0046 mol; the charging quantity is obtained by multiplying the charging time and the charging current, and when the charging quantity is X Ah, the corresponding oxygen generation quantity is 0.0046X mol;

calculating to obtain theoretical pressure P according to an ideal gas state equation PV ═ nRT; where V represents the volume of the gas chamber inside the cell, n represents the amount of gaseous material, T represents the absolute temperature (dependent on the ambient temperature), and R represents the gas constant.

Further, for the batteries of the same batch, after the charging process is fixed, the charged electricity quantity is a fixed value, and the theoretical pressure is also a fixed value.

Compared with the prior art, the invention has the following beneficial effects:

the method is simple and easy to operate, can accurately detect each cell of each battery in batches, ensures that the spent acid of the cell of each battery is completely extracted, is favorable for reducing the difference between the cells of each battery, and prolongs the service life of each battery.

Drawings

FIG. 1 is a schematic view of a first installation of a test rubber cap in the method of the present invention;

FIG. 2 is a schematic view of a second installation of the test rubber cap in the method of the present invention.

Detailed Description

The invention will be described in further detail below with reference to the drawings and examples, which are intended to facilitate the understanding of the invention without limiting it in any way.

The invention designs a test rubber cap, as shown in fig. 1, a battery pole group 1, a battery jar 2, a battery middle cover 3 and an acid injection nozzle 4 are shown in the figure. In figure 1, the testing rubber cap 5 adopts a through hole rubber plug, when in use, the testing rubber cap 5 is tightly matched with the inner wall of the acid injection nozzle 4, the testing rubber cap 5 is provided with a pressure sensor 6, and the pressure sensor 6 is connected with a pressure display 7.

Or, the testing rubber cap can also be buckled on the acid adding port of the battery, as shown in fig. 2, the testing rubber cap 8 is tightly matched with the outer edge of the acid injection nozzle 4, and the testing rubber cap 8 is provided with the pressure sensor 6.

The test rubber caps with the two structures and the acid injection nozzle form a sealing structure; the valve opening pressure of the test rubber cap is not lower than 50 kPa. The pressure sensor can realize the monitoring of the internal pressure and temperature of the battery; the pressure sensing data is processed through the data processing center, and the internal pressure value can be monitored through the processing center.

The process of judging whether the residual acid is completely extracted is as follows:

at the final stage of formation, the battery is in a full-charge state, and the acid-drawing current is 0.01C₂～0.1C₂After constant current charging for 3h, acid extraction is started, and residual acid is extracted.

And after the acid extraction is finished, turning off a power supply of a charger, stopping charging, and standing for 30-60 min.

And after the standing is finished, covering a test rubber cap, and standing for 5-10 min.

The charger is turned on, and the charging current is set to 0.005C₂～0.01C₂When charging is started, gas starts to be generated inside the battery, and the pressure gradually increases.

The reaction formula during charging is as follows: h₂O→2H⁺+1/2O₂+2e^-；

According to the formula, 2mol electrons are generated while 0.5mol oxygen is generated; and 1mol of electrons has N-N-NA-6.02-10²³Electrons; q6.02 x 10²³*1.6*10^-19＝9.632*10⁴Coulombs; 2mol electron electric quantity Q2 x 9.632 x 10⁴＝19.264*10⁴Coulombs.

The charge amount can be calculated according to the current and time of charging, and then the electron generation amount and the gas evolution amount are calculated in turn:

from 1A × h 3600C, i.e. the amount of electricity charged to 1A × h, 0.0186mol of electrons and 0.0046mol of oxygen generation can be calculated.

In summary, the charge capacity is X Ah, and the oxygen generation amount is 0.0046X mol.

From PV — nRT, T can be considered constant, V the internal gas chamber volume, R constant, in a short time, the amount of gas produced can be calculated from the amount of charge, and then the theoretical pressure P value can be calculated, which can be compared with the actual detected value:

if the actual pressure P₁When the theoretical pressure P can be reached quickly, the saturation degree of the partition plate is judged to be higher, and the residual acid is not completely pumped; if the actual pressure P₁And when the theoretical pressure P can not be reached all the time, judging that an oxygen channel exists on the partition plate and the residual acid is completely pumped.

After the charging process is fixed, namely the charging amount is a fixed value, the generated gas amount is a fixed value, in other words, after the charging is finished, if the generated gas is not absorbed by the negative electrode and is completely discharged into the gas chamber, the pressure value is a value which can be calculated, by monitoring the change of the internal pressure, if the pressure value does not reach a calculated value after the charging is finished, the fact that part of the gas can be absorbed by the negative electrode is indicated, the existence of an oxygen channel is indicated, namely the residual acid is completely extracted, if the pressure value quickly reaches the calculated value after the charging is finished, the fact that the gas channel does not exist between the positive electrode and the negative electrode is indicated, the oxygen generated by the positive electrode cannot be transmitted to the negative electrode, and the whole oxygen is discharged into the gas chamber, namely the residual acid is not completely extracted.

To verify the effectiveness of the method of the invention, the following tests were carried out:

the air chamber of the conventional full-impregnation 6-DZF-20Ah type battery has the internal air chamber volume of 0.033L, the temperature of 293.15 (normal temperature 25 ℃), the R is a constant, the value is 8.314, the P is calculated to be 3.6kPa according to the charging capacity of 0.01Ah and the quantity of substances generated by gas of 0.000046mol, namely the conventional full-impregnation 20Ah, the later charging capacity of 0.01Ah and the maximum pressure value of a single cell of 3.6 kPa.

After the acid pumping of the battery of the type is finished, standing for 30min, covering a test safety valve after the acid pumping is finished, starting charging after 5min, setting the charging current to be 0.1A, setting the charging time to be 6min, setting the total charging capacity to be 0.01Ah, and observing the pressure value in the battery after 6min is finished.

Wherein the pressure values of the first single lattice and the sixth single lattice quickly reach 3.6kPa, and the pressure values of the second single lattice, the third single lattice, the fourth single lattice and the fifth single lattice are respectively 1.3kPa, 1.5kPa, 1.4kPa and 1.3 kPa.

After the end, the injector is used for extracting the residual acid for each single cell, the first single cell and the sixth single cell respectively extract 5ml and 6ml of the residual acid, the residual acid is not completely extracted, and the residual acid can not be extracted from the other single cells and has no residual acid, thereby proving that the method is effective.

The embodiments described above are intended to illustrate the technical solutions and advantages of the present invention, and it should be understood that the above-mentioned embodiments are only specific embodiments of the present invention, and are not intended to limit the present invention, and any modifications, additions and equivalents made within the scope of the principles of the present invention should be included in the scope of the present invention.