How to choose right batteries for RFID tags?
RFID tags are used widely today, so here comes a question--how can we choose the right battery for them?
Normally, there are three kinds of batteries can be used, Lithium manganese dioxide button cell (CR button battery), Lithium-Manganese card battery wrapped with soft aluminium foil (CP battery), and ultrathin battery. After being acquainted with their characters, you can know how to choose according your products’ requirement.
CR button batteries
This kind of batteries are popularly used in RFID system manufacturers for its advantage in price, so if you have no requirement in thickness as well as in high pulse current, and you don’t need them work more than 2 years, CR button battery will be your best choice.
Reasons are as follow:
1. The prices range from 0.5 RMB~3 RMB according to different capacities, they could help saving your products’ costs.
2. They can release 65%~70% of their nominal capacities in the case of small current discharge, so their working life should be 2.5 years~3 years. What has caused such a short working time? Because the plastic seal ring and the metal shell can’t form a real and integral whole, as time goes on, the seal ring began to be aged, the electrolyte inside began to volatile, and then the energy will be consumed quickly. In the other word, even the batteries’ nominal capacity has reached your requirement of working time, they will run out 2 or 3 years later.
Here, we can have a high temperature of 65℃ and high humidity of relative humidity-90% test to demonstrate the batteries’ quality.
Notes are as follow,
1. The thinnest CR button can only be 1.6mm, they are hard to reach requirement of an ultrathin tag.
2. Only small discharge current can be accepted by CR button, the correlation curve is the comparison of a CR button and a CP button with same capacity when discharging at a 15mA and normal temperature.
If a high pulse current, or the working time must be longer than 3 years and high safety performance are required, then the CP battery should be your choice.
Reasons are as follow:
1. Using soft aluminium foil in structures, which greatly reduces the probability to occur explosion, fire.
2. Different shape and size can be designed, which can meet your individual requirements.
3. Laminated electrodes structure, which can accept higher discharge current, even up to 3C.
4. Low self-discharge rate insures its storage life 8 years.
5. Working temperature: -40℃~75℃
6. Lightweight, can be 40% lighter than a button battery with a same capacity.
7. High capacity, can be 10% higher than a button battery with a same volume.
8. Small, can be 15% smaller than a button battery with a same capacity.
In view of these advantages above, CP batteries should be the ideal power source of RFID tags.
As we know, there are companies like, SuZhou MuLan Ele&Tec Co.,Ltd and ViewSonic choose CP buttery for their products.
There are three kinds of Ultrathin batteries, 3.0V CP battery as mentioned above, 3.7V lithium-polymer battery, and 1.5V Zn-Mn Battery.
Comparisons are as follow:
1. CP battery’s capacity is 2.5 times higher than a Lithium-Polymer battery with a same volume. The working life can be up to 5 years or longer.
2. Li-Po can be charged though its low capacity.
3. For the energy-to-weight ratio, CP battery is the highest, Li-Po is the lowest.
In conclusion, CR button battery is the most economical, but you have to make choice according to your RFID tags’ technical requirement.
Any question, please contact our engineer.