Methods for detecting oxygen recombination efficiency in AGM batteries

Abstract

This invention provides a method for detecting the oxygen recombination efficiency of AGM batteries, belonging to the field of lead-acid battery technology. The method first weighs the oxygen adsorption device to obtain m1, and then charges a fully charged battery until a mixed gas is released. The resulting mixed gas is then subjected to deacidification and drying, and then adsorbed by the oxygen adsorption device to obtain the remaining gas. After oxygen testing, the test continues. After t hours of testing, the oxygen adsorption device is weighed to obtain m2. Then, according to n1=(m2-m1) / M 氧 Calculate the amount of oxygen contained in the battery under test, n1; then select a supersaturated battery and determine the oxygen content using the above steps to obtain the amount of oxygen contained in the supersaturated battery, n2; finally, apply the formula η 氧气 The oxygen recombination efficiency of the battery under test can be obtained by calculating (n2-n1) / n2. The detection method of the present invention can ensure that the gas values ​​of collected oxygen are more reliable.

Description

Technical Field

[0001] This invention belongs to the field of lead-acid battery technology, and more specifically, relates to a method for detecting the oxygen recombination efficiency of AGM batteries. Background Technology

[0002] AGM batteries are valve-regulated sealed lead-acid batteries using ultra-fine glass fiber separators (AGM). They are widely used in automotive start-stop systems due to their excellent safety, maintenance-free operation, and long lifespan. AGM batteries are valve-regulated sealed batteries with a lean electrolyte design, where the electrolyte is adsorbed within the separator, which is in a partially saturated state. During charging, oxygen generated at the positive electrode can be transferred to the negative electrode through micropores in the separator for an oxygen recombination reaction. The efficiency of this oxygen recombination reaction directly affects the battery's charging efficiency, water consumption, and other performance characteristics. However, existing testing methods only measure oxygen recombination efficiency under theoretical and ideal conditions, and cannot rule out interference from grid oxidation and corrosion during battery charging, as well as the possible presence of hydrogen in the collected gas, leading to significant errors in actual measurement data. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method for detecting the oxygen recombination efficiency of AGM batteries. This detection method can significantly reduce measurement errors, making the measurement results more accurate and reliable.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a method for detecting the oxygen recombination efficiency of an AGM battery when it is deactivated, the detection method comprising the following steps:

[0005] 1) Before the test begins, the oxygen adsorption device is weighed and recorded as m1;

[0006] Use a fully charged battery as a spare;

[0007] 2) Recharge the fully charged battery until a mixed gas is produced, and start timing at this point;

[0008] 3) While charging a fully charged battery to release a mixed gas, the resulting mixed gas is treated with an alkaline solution to obtain a deacidified gas.

[0009] 4) The gas after acid removal is then dried using a drying device to obtain dried gas;

[0010] 5) After drying, the gas is passed through an oxygen adsorption device to absorb oxygen, and the remaining gas is obtained;

[0011] 6) The remaining gas is tested for oxygen to determine whether oxygen is present in the remaining gas;

[0012] If oxygen is present in the remaining gas, the adsorption capacity of the oxygen adsorption device must be increased and the test must be repeated.

[0013] If no oxygen is present in the remaining gas introduced, the test continues.

[0014] 7) The test ends after t hours. At this time, the oxygen adsorption device is weighed again and recorded as m2.

[0015] The amount of oxygen adsorbed by the oxygen adsorption device is calculated according to the following formula, which gives the amount of oxygen in the battery under test, n1.

[0016] The specific formula is as follows: n1=(m2-m1) / M 氧 , of which M 氧 This refers to the molar mass of oxygen.

[0017] 8) Then, select a supersaturated battery (i.e., an AGM battery with a supersaturated separator) and use steps 1) to 7) to determine the oxygen content, obtaining the amount of oxygen contained in the supersaturated battery (i.e., an AGM battery with a supersaturated separator) as n2 = (m2' - m1') / M 氧 ;

[0018] 9) Based on the formula η 氧气 The oxygen recombination efficiency η of the battery under test can be obtained by calculating (n2-n1) / n2. 氧 gas.

[0019] In one possible implementation, in step 1), the fully charged battery is obtained by fully charging the battery under test.

[0020] In one possible implementation, in step 2), the charging current for the fully charged battery is 0.01C. 20 .

[0021] In one possible implementation, in step 3), the alkaline solution is an aqueous sodium hydroxide solution.

[0022] In one possible implementation, the concentration of the sodium hydroxide aqueous solution is 5–10 wt%.

[0023] In one possible implementation, the oxygen adsorption device is filled with oxygen adsorbent.

[0024] In one possible implementation, in step 7), t is more than 1 hour.

[0025] In one possible implementation, step 6) involves the oxygen test, which includes the following procedures:

[0026] The remaining gas is passed into a ferrous chloride solution to test whether oxygen is present in the remaining gas;

[0027] Under normal circumstances, ferrous chloride solution is green. If oxygen is present in the remaining gas, the ferrous chloride solution will begin to change color. In this case, the adsorption capacity of the oxygen adsorption device must be increased and the test must be repeated.

[0028] If no oxygen is present in the remaining gas, the ferrous chloride solution will not change color, and the test should continue.

[0029] In one possible implementation, the ferrous chloride solution is acidic when the residual gas is introduced.

[0030] In one possible implementation, the pH of the acidic ferrous chloride solution is 3 to 5.

[0031] The beneficial effects of the method for detecting the oxygen recombination efficiency of AGM batteries provided by this invention are as follows: Compared with the prior art, by comparing the amount of oxygen generated by the test battery and the oversaturated battery within a certain period of time, the influence of various factors such as current consumption, grid corrosion, and heat consumption during the actual charging process can be effectively avoided. At the same time, the addition of a drying device and an oxygen adsorption device, and the use of ferrous chloride solution to detect whether the oxygen is completely absorbed, ensures that the collected oxygen gas values ​​are more reliable and closer to the true values.

[0032] The detection method of the present invention uses an oxygen adsorbent to absorb oxygen. Measuring the weight of the adsorbed oxygen is more accurate than measuring the volume of oxygen, which can reduce measurement errors.

[0033] The detection method of the present invention ensures complete absorption and reduces measurement error by detecting oxygen in the remaining gas.

[0034] The detection method of the present invention calculates the recombination efficiency by measuring the difference in oxygen production between the test battery and the supersaturated AGM battery, which can effectively avoid the influence of battery side reaction consumption on the measurement results. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 The flowchart illustrates the detection process for the oxygen recombination efficiency of an AGM battery, as provided in this embodiment of the invention. Detailed Implementation

[0037] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0038] Please refer to the following: Figure 1 The present invention will now describe a method for detecting the oxygen recombination efficiency of an AGM battery during start-up and shutdown. The method for detecting the oxygen recombination efficiency of an AGM battery during start-up and shutdown includes the following steps performed sequentially:

[0039] 1) Before the test begins, the oxygen adsorption device filled with oxygen adsorbent is weighed and recorded as m1.

[0040] The battery under test is fully charged to ensure that it is fully charged during the test (normal AGM batteries have partially saturated separators), thus obtaining a fully charged battery.

[0041] 2) Charge a fully charged battery at 0.01C. 20 The current is applied again until a mixed gas is precipitated, resulting in a mixed gas. Timing begins at this point (where C...). 20 (Battery 20-hour rate capacity);

[0042] 3) While charging the fully charged battery and releasing the mixed gas, the resulting mixed gas is treated with a 5-10 wt% sodium hydroxide aqueous solution (in this embodiment, the concentration of the sodium hydroxide aqueous solution is 10 wt%, and this process is to remove acid mist from the mixed gas) to obtain the deacidified gas.

[0043] 4) The gas after acid removal is then dried by a drying device containing a desiccant (anhydrous calcium chloride is used as the desiccant in this embodiment, but other desiccants that can absorb moisture can also be used) to obtain the dried gas.

[0044] 5) Take the dried gas and pass it through an oxygen adsorption device filled with oxygen adsorbent. At this time, the oxygen in the dried gas is absorbed by the oxygen adsorbent, and the remaining gas is obtained.

[0045] 6) The remaining gas is passed into a ferrous chloride solution (acidic conditions) (pH is generally 3-5, pH is 4 in this example) to test whether oxygen is present in the remaining gas;

[0046] Under normal circumstances, ferrous chloride solution is green. If oxygen is present in the remaining gas, the ferrous chloride solution will begin to change color. In this case, the adsorption capacity of the oxygen adsorption device must be increased and the test must be repeated.

[0047] If no oxygen is present in the remaining gas, the ferrous chloride solution will not change color, and the test should continue.

[0048] 7) The test ends after t hours (the test usually lasts for more than 1 hour, i.e., t≥1, in this example t=1.5). At this time, the oxygen adsorption device is weighed again and recorded as m2.

[0049] The amount of oxygen adsorbed by the oxygen adsorption device is calculated according to the following formula, which gives the amount of oxygen in the battery under test, n1.

[0050] The specific formula is as follows: n1=(m2-m1) / M 氧 , of which M 氧 This refers to the molar mass of oxygen.

[0051] 8) Then, select an AGM battery with a supersaturated separator and determine the oxygen content using steps 1) to 7) above. The amount of oxygen in the supersaturated AGM battery is n2 = (m2' - m1') / M. 氧 ;

[0052] This step, by comparing the amount of oxygen contained in the battery under test (n1) with the amount of oxygen contained in the AGM battery (n2), can eliminate the influence of various interfering factors such as current consumption, grid corrosion, and heat consumption during the charging process of the battery under test.

[0053] Unsaturated batteries exhibit recombination reactions (oxygen enters the negative electrode and is consumed), current consumption, and grid corrosion; oversaturated batteries only exhibit current consumption and grid corrosion, because oversaturated oxygen cannot reach the negative electrode and cannot undergo recombination reactions; the difference between the two types of batteries is recombination consumption (reaction efficiency). In this invention, the battery under test is an unsaturated battery, and the AGM battery with an oversaturated separator is an oversaturated battery.

[0054] 9) Based on the formula η 氧气 The oxygen recombination efficiency η of the battery under test can be obtained by calculating (n2-n1) / n2. 氧 gas.

[0055] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for detecting oxygen recombination efficiency of a start-stop AGM battery, characterized in that, The detection method comprises the following steps: 1) Before starting the detection, first weigh the oxygen adsorption device, denoted as m1; Take the battery in full charge state as standby; 2) Charge the battery in full charge state to have mixed gas precipitated, obtain the mixed gas, and start timing at this time; 3) While charging the battery in full charge state to precipitate the mixed gas, the obtained mixed gas is treated by an alkaline solution to obtain the acid-removed gas; 4) The acid-removed gas is dried by a drying device to obtain the dried gas; 5) Take the dried gas to be absorbed by the oxygen adsorption device to obtain the residual gas; 6) The residual gas is subjected to oxygen inspection to determine whether there is oxygen in the residual gas; If there is oxygen in the residual gas, the adsorption capacity of the oxygen adsorption device must be increased, and the test is re-performed; If there is no oxygen in the residual gas, the detection test is continued; 7) The detection test is ended after t hours, t hours are more than 1 hour, and the oxygen adsorption device is weighed again at this time, denoted as m2; The amount of substance of the oxygen adsorbed by the oxygen adsorption device is calculated according to the following formula, that is, the mass n1 of the oxygen contained in the battery to be detected is obtained; The specific formula is as follows: n1= (m2-m1) / M 氧 wherein M 氧 is the molar mass of oxygen; 8) Then select the separator supersaturated battery, using steps 1) ~ 7) to determine the oxygen content, get the separator supersaturated battery containing oxygen in the amount of n2= (m2'-m1') / M 氧 ; 9) The oxygen recombination efficiency η of the battery under test can be calculated according to the formula η = (n2 - n1) / n2 氧气 氧气 .​ 2. The method for detecting the oxygen recombination efficiency of AGM batteries as described in claim 1, characterized in that, In step 1), the battery in full charge state is prepared by completely charging the battery to be detected.

3. The method for detecting the oxygen recombination efficiency of AGM batteries as described in claim 1 or 2, characterized in that, The current for charging the battery in full state of charge in step 2) is 0.01 C 20 .

4. The method of claim 1 or 2, wherein the AGM battery is a start-stop AGM battery. In step 3), the alkaline solution is a sodium hydroxide aqueous solution.

5. The method for detecting the oxygen recombination efficiency of AGM batteries as described in claim 4, characterized in that, The concentration of the sodium hydroxide aqueous solution is 5-10 wt%.

6. The method for detecting the oxygen recombination efficiency of an AGM battery as described in claim 1, 2, or 5, characterized in that, The oxygen adsorption device is filled with an oxygen adsorbent.

7. The method of claim 1, 2 or 5, wherein the AGM battery is a start-stop AGM battery. In step 6), the oxygen inspection Comprises the following processes: The residual gas is introduced into a ferrous chloride solution to test whether there is oxygen in the residual gas; Under normal circumstances, the ferrous chloride solution is green, if there is oxygen in the residual gas, the ferrous chloride solution begins to change color, at this time, the adsorption capacity of the oxygen adsorption device must be increased, and the test is re-performed; If there is no oxygen in the residual gas, the ferrous chloride solution does not change color, and the detection test is continued at this time.

8. The method for detecting the oxygen recombination efficiency of AGM batteries as described in claim 7, characterized in that, When the residual gas is introduced, the ferrous chloride solution is acidic.

9. The method for detecting the oxygen recombination efficiency of an AGM battery as described in claim 8, characterized in that, The pH value of the acidic ferrous chloride solution is 3-5.

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