Development of reliable and long life VRLA batteries

Since 1967 Matsushita battery industry (Panasonic) has carried out the production and sales of the VRLA battery for emergency back up and other applications. In 1985 the large-sized VRLA batteries, 50 Ah to 3000 Ah capacity and 7 to 9-year life batteries, were developed mainly for communications. The total production of large-sized VRLA battery in our company for the last 15 years is going to reach 1 million cells. Here we looked back upon the results of the past 15 years, and a consensus was established about the reliability and the long-life technology of the large-sized VRLA battery. From accelerated life tests and the actual use life tests, equivalent results were obtained and the battery design based on the assumption failure modes were verified. From the validation of the battery design and the accelerated life test method, it is proven that the life expectancy of the VRLA battery is 13-15 yrs., based on these results.