Service life, safety and reliability of the hottes

Life and safety reliability of valve regulated lead-acid batteries

Abstract: the manufacturing process and use of valve regulated lead-acid batteries are analyzed and discussed, and some problems about life and safety reliability of valve regulated lead-acid batteries are put forward

key words: valve regulated lead-acid battery; life; Reliability

valve regulated lead-acid battery (VRLAB) has entered the Chinese market with imported foreign telecommunication equipment for about ten years. Now VRLAB manufacturers are all over Chinese Mainland and all over the world

however, in practical applications, new problems continue to appear in VRLAB, especially the service life, safety and reliability of VRLAB have always been the focus of attention of users and manufacturers. The author has been engaged in the promotion, sales and technical service of batteries for a long time, and now puts forward some immature ideas for the reference of technicians and users in battery related industries. 1vrlab history

in 1982, VRLAB was born (in fact, the original alkaline rechargeable battery has already had valve controlled function); In 1985, American GNB company (now acquired by exide company) developed and developed a high-capacity VRLAB, which was immediately welcomed by the telecommunications industry because of its maintenance free (without battery water), good safety (without escaping gas) and compact design (compared with the traditional full liquid open battery, it occupies less space) (modern electronic equipment in the telecommunications industry has higher environmental requirements, and VRLAB can be in the same room with telecommunications equipment)

in 1995, Philadelphia scientific published a research report, establishing that the battery water loss is the basis for determining the VRLAB life, that is, when 10% of the water in the VRLAB is lost, the actual capacity of the battery is reduced to less than 80% of the rated capacity, and the establishment of the Strategic Advisory Committee on major technical equipment is completed, it is said that the service life of the battery has expired

many manufacturers accept this standard and manufacture batteries according to this standard, adding acid, water and sealing, with a view to reaching the design life of 20 years

however, from 1995 to 1996, telecom users in Europe and the United States, who were the first to use VRLAB, began to complain about the unstable reliability of VRLAB. The main problems were the increase of floating charge current, plate corrosion, capacity decline, out of control charging heat and battery drying up

it was only at the telesconference in Budapest in 1997 that defects in the electrochemical design of VRLAB were found. Many battery failure problems are caused by the self discharge effect of the negative plate. Similarly, although there is no need to power up the circulating recombination of oxygen, what problems should be paid attention to when installing the tensile testing machine? Pool water, but it will cause self discharge effect and capacity decline, and the early VRLAB capacity even fell below 65% Ce

after 1998, in view of the above design defects, many manufacturers developed a new VRLAB with palladium catalyst on the valve cover

in 2000, a large number of new VRLAB with catalyst metal palladium were introduced. It improved the sealing process, strengthened the shell cover design, and tried to solve the fundamental defect of VRLAB negative plate self discharge, which shortened the battery life

2 some examples of domestic VRLAB usage

there are many reasons for VRLAB failure or early termination of battery life (less than 20 or 10 years of design life)

compared with open cell batteries, the main theoretical points of VRLAB are:

1) cathode absorption battery (so the negative plate is more than the positive plate, which is easy to absorb oxygen)

2) valve controlled battery (the internal pressure is controlled by a special safety valve, which is easy for gas recombination)

3) sealed battery (special material shell, specially sealed, so moisture will not escape)

4) H + suppression battery (special negative plate, so that H ions will not precipitate or less precipitate, and will not become H2 to escape)

now it seems that the above points have limitations, resulting in large differences in manufacturing and problems in product quality, making the design life and reliability index of the battery unconvincing

think about it from another angle:

1) how much larger is the negative plate than the positive plate, which can make the best absorption of oxygen

2) what is the internal pressure value of the battery controlled by the safety valve, which is the easiest for gas recombination

3) how to seal it so that water will not escape

4) how to make a special negative plate so that H ions will not or less precipitate

manufacturers have different views and practices on the above issues

at present, the results of various VRLAB on-site use show that the VRLAB of new materials workers in many domestic enterprises and scientific research institutions has been running for more than 6 years (Deka battery is in Hebei Zhengding Telecom Bureau), but many batteries began to decline in capacity and fail in about 5 years, especially some domestic brands and brands with design defects (such as sealing process problems)

in fact, it has been less than 20 years since the first VRLAB was developed. Only the EPM manufacturer's data (2000) shows that they have been doing the actual VRLAB cycle charge and discharge test for more than 5 years. It takes 2 ~ 3 days each time, and more than 1000 actual charge and discharge tests have been carried out

3 enlightenment and thinking

1) science and technology are constantly developing, and VRLAB will have new development, both in theory and Practice (unfortunately, there are too few personnel and achievements in the domestic battery industry and related research and development)

2) battery manufacturers should keep abreast of the latest developments in the industry, and avoid blindly following the trend and making similar products in a swarm (for example, the same type of plate manufacturers are used by dozens of battery assembly plants, how can there be high quality?) It is estimated that VRLAB can be used to establish normal working methods, and manufacturers will face a new round of elimination, just like the elimination of KaiKou battery factory 10 years ago

3) the service life of batteries, especially domestic batteries, should not be blindly publicized for as long as 10 years, 15 years, or even longer. There is no experimental evidence to support it. Some manufacturers replace them for 8 years. I don't know the reason? In fact, the reasons that affect the service life include the manufacture of valve cover, the setting of valve pressure, the manufacture of electrode plate and other manufacturer reasons, as well as overcharging, high temperature and other use reasons, as well as the limitations of VRLAB theory of negative plate depolarization

4) safety and reliability of batteries. Any battery may be dangerous during storage, transportation and use under inappropriate conditions, including the escape of toxic gases (as it is) explosion, acid leakage, etc