The requirement of a battery in an RFID tag depends upon the type of tag used in an application. There are three types of tags- active, passive, and semi-passive tags. Active tags require a battery. The battery functions as a source of power and continuously transmits signals. Although these tags provide a long range of reading, the life span of the tags is very short. Moreover, the price of the tags is also very high. Thus, they are used in high-cost applications such as asset tracking, logistics, etc.
On the contrary, passive tags do not require a battery. These have no internal source of power. Thus, the tags get activated only through the radio waves transmitted by the RFID reader. These may have a short range of reading, but the lifespan of the batteryless tag is very long. Also, the price of the passive tags is very economical. Due to their low prices, there is heavy demand for these tags in wide applications. The tags, due to the absence of a battery, can work in challenging weather conditions. Passive tags or batteryless tags are very useful in outdoor applications because they are not affected by water or metals.
Semi-passive tags contain batteries, but they do not function like active tags. They do not transmit signals actively. They use a battery to awaken the tag when they receive electromagnetic fields from the RFID reader. The battery in semi-passive tags assists integrated circuits in reflecting the waves. The tags have a higher cost than passive tags and lower than active ones. The life span is short due to the presence of a battery.