Future Development Prospect of Batteries and Battery Combination Effect

Battery packs are used in combination. The basic way of combination is parallel and series structure. The laboratory life of batteries is the data provided by the inspection department, which is often far from the actual value in use. Although the reasons for this situation are various, the basic factors are common. This article will analyze these factors. The measures to give full play to the use value of storage battery are put forward.

1. The concepts of monolithic batteries and batteries

The batteries manufactured by factories are single batteries or single batteries. Monomer batteries refer to the batteries with the smallest independent electrochemical voltage unit. Alkaline nickel-cadmium batteries are 1V for each cell, 2V for lead-acid batteries, 3V for lithium iron phosphate batteries and 3.6V for lithium manganate batteries. In the case of low power supply, a battery, such as mobile phone and home flashlight, is often used to supply power with a single lithium battery. In many cases, batteries must be combined into large capacity and high voltage batteries to meet the needs of equipment. For example, 12V batteries for starting gasoline vehicles, 48V batteries for communication base stations, 96V batteries for railway locomotives and 144-288V batteries for electric vehicles are all made up of single batteries in series.

In the interior of the larger capacity battery, the larger capacity is generated by parallel monomer battery. The plates of lead-acid batteries for automobiles are 15Ah each, and a series of batteries with 15Ah steps are formed in parallel. The soft pack of lithium batteries is similar to the plate of lead-acid batteries. Each pack of lithium batteries is 20Ah, which can form a series of batteries with 20Ah as a step. With the combination of 2Ah cylindrical batteries of 18650 type, single batteries with arbitrary large capacity can be obtained theoretically in parallel.

In practical use, two problems are often misunderstood by users. One is the battery life published by battery factories and stipulated in national standards, which refers to the life of single batteries, not the life of batteries. The second is the lower limit of the discarded capacity of batteries. It is the usual practice in the battery industry to reduce the structural capacity to 80% of the nominal capacity by cyclic test, and the test will be terminated. Battery industry is used to providing this data to users, many users mistakenly believe that this value is the use of scrap standards, in many industries, continue to use this data. In fact, according to different user conditions, scrapping standards will vary greatly.

In mechanical mechanism, parallel connection can increase reliability. In batteries, many people think the same is true. In fact, the opposite is true. Whether in series or in parallel, the reliability of batteries is lower than that of single batteries, and the damage rate of single batteries is much lower than that of batteries. However, in order to meet the existing equipment requirements, the models produced by battery factories in China are: 2V, 4V, 6V, 8V, 12V, 24V. Conventional models are 2V, 6V and 12V. It is expected that R&D scientists in the battery industry will bring the battery industry of China to the top 10 in the international battery industry as soon as possible.