Battery failure and maintenance

　　1 Introduction

　　 Since the French scientist Plante invented the lead-acid battery in 1859, it has a history of more than 100 years. Like other chemical power sources, it is a device that converts between electrical energy and chemical energy. Because of its high electromotive force, good charge and discharge reversibility, wide operating temperature range, clear electrochemical principles, easy-to-master production technology, abundant and low-cost raw materials, it has been widely used. With the vigorous development of science and technology, since the 1950s, traditional lead-acid batteries have been continuously technologically transformed. In particular, the advent of storage batteries (VRLA) overcomes the headache of acid and acid mist that are prone to overflow, and enables it to be used with electronic equipment. It conforms to the historical development trend of user requirements and makes it easy to use. The application field is broader.

　　1.1 Product market prospects

　　According to statistics: the sales revenue of lead-acid batteries worldwide in 1999 It is about 19.8 billion US dollars, and it is increasing at a rate of 5% every year.

　　 In my country, with the sustained and rapid economic development, basic industries such as the automobile industry, communications, electric power, transportation, railways, and computers are developing very rapidly. These industries are all in a high growth rate. During this period, the increasing demand for batteries has greatly promoted the development of the battery industry. In the past ten years, the demand for lead-acid batteries in my country has grown rapidly at a rate of 10% per year.

　　 According to the figures provided by the 'Tenth Five-Year Plan for the Battery Industry' published by the China Battery Industry Association in October 2000: The national lead-acid battery output in 1999 reached 26.25 million KVAh , With annual sales of 1.05 billion U.S. dollars. The goal of lead-acid batteries in the Tenth Five-Year Plan is to take 26.25 million KVAh as the base, with an average annual growth rate of 5%. The output in 2005 reached 35 million KVAh.

　　 The statistical results show that the fully enclosed maintenance-free lead-acid battery will gradually replace the traditional open-ended lead-acid battery and it will become the development trend of the lead-acid battery industry in the future.

　　1.2 working principle

　　The working principle of the battery basically follows the traditional lead-acid battery, and its positive electrode is active The material is lead dioxide (PbO2), the negative electrode active material is spongy lead (Pb), and the electrolyte is dilute sulfuric acid (H2SO4). The electrode reaction equation is as follows:

　　 Positive electrode ：PbO2+H2SO4+2H++2e-←→PbSO4+2H2O

　　 Negative electrode: Pb+H2SO4←→PbSO4+2H++2e-

　　 The entire battery reaction equation:

　　 Pb+PbO2+H2SO4←→2PbSO4+2H2O

During the charging process of an ordinary lead-acid battery, the positive electrode releases oxygen and the negative electrode releases hydrogen:

　　 Positive electrode: H2O→1/2O2+2H++2e-

　　 Negative electrode: 2H++2e-→H2

　　 It can be seen from the above reaction formula that there is a water decomposition reaction during the charging process. When it is charged to 70%, oxygen begins to precipitate, and when the negative electrode is charged to 90%, hydrogen begins to precipitate. Due to the precipitation of hydrogen and oxygen, if the gas produced by the reaction cannot be reused, the battery will lose water and dry up.

　　 The battery has made important improvements in structure and materials. The positive grid uses lead-calcium tin-aluminum quaternary alloy or low antimony multiple alloy, and the negative grid uses lead-calcium tin. Aluminum quaternary alloy, the separator is made of ultra-fine glass fiber wool (AGM), and the tight assembly and lean liquid design are used. A one-way safety valve is set in the upper cover of the battery. This battery structure uses antimony-free lead-calcium-tin-aluminum quaternary alloy to increase the overpotential of hydrogen evolution at the negative electrode, thereby inhibiting the precipitation of hydrogen. At the same time, a special safety valve is used to keep the battery at a certain internal pressure and ultra-fine glass fiber The cotton (AGM) separator uses the cathode absorption technology to reserve a gas channel between the positive and negative electrodes and in the separator through a lean-liquid design. Therefore, when charging at the specified charging voltage, the oxygen (O2) precipitated from the positive electrode can be transferred to the surface of the negative plate through the separator channel and reduced to water (H2O). The reaction formula is as follows:

　　The unique internal oxygen cycle reaction mechanism of the valve-regulated sealed lead battery

　　 This is the unique internal oxygen cycle reaction mechanism of the valve-regulated sealed lead battery. This charging During the process, the water in the electrolyte is almost not lost, so that the battery does not need to add water during use. Contact: 18038382979