3.7V 450mAh Lithium Ion Battery Design Scheme of Mobile Payment Terminal

Foreword: (keyword: mobile payment terminal, polymer battery) mobile payment is a service mode that allows users apply the mobile terminal to pay for commodity or service. Units or individual send payment instrument directly or indirectly by mobile device, internet or closed distance sensor and then make monetary payment and capital transfer to realize mobile payment function. Mobile payment integrates terminal device, internet, APP provider and financing institution to provide financial service including monetary payment, fee payment, etc. for users. Mobile payment terminal is charged by lithium ion battery pack with high performance so as to help products have continuous, efficient and stable operation.

Lithium ion battery design requirements of mobile payment terminal:

Based on the customers’ requirements and specification, design battery pack to assort with host machine and integrate lithium ion battery and protective performance into the solution. During the design process of the whole scheme, take perfect integration with host machine for direction, regard assurance of safety performance of battery, battery pack and the whole system as premise, and make the conformation of relevant design regulations and certification as first priorities. In order to make sure the security and reliability of lithium ion battery, the battery pack applies multi-protection inside to avoid being damaged by overcharging, over-discharging or short circuit.

1）Design requirement of the type of lithium ion battery: 402060-1S1P/450mAh/3.7V

2）Design requirement of electric circuit:

　　1、Over-charged protection voltage of single battery: 4.28±0.25V

　　2、Over-charged recovery voltage of single battery: 4.08±0.50V

　　3、Over-discharged protection voltage of single battery: 3.00±0.08V

　　4、Over-discharged recovery voltage of single battery: 3.00±0.08V

　　5、Over-discharge cut-off current of battery pack (10ms): 1.5~3.5A

　　6、Over temperature protection value of battery pack (restorable): 70±5℃

　　7、The finished product has protective function of short circuit and reverse-charging.

3）Design requirement of cycle life: 300~500 times (national standard of charging and discharging)

4）Design requirement of housing dimension: refer to host machine housing

二、Lithium ion battery design scheme of mobile payment terminal:

1）Guard plate (PCM): it is protective circuit of rechargeable lithium ion battery pack. Because of the chemical characteristics of lithium ion battery, it needs protective function of intelligent capacity calculation, overcharging, over-discharging, short circuit, overcurrent, etc. so as to avoid combustion, explosion, etc.

2）Protection IC: it is the chip has main protective function in the design scheme. The chip monitors the cell on the functions of overcharging, over-discharging, overcurrent, short circuit, etc. at any time, which helps the battery works under safe, stable and efficient circumstance.

3）Temperature switch: it is designed for temperature protection. When the battery is heated up to 70±5℃ due to any issues, the temperature switch begins to protect the battery.

4）Polymer lithium ion battery: 402060P/450mAh/3.7V Li- Polymer cell

5）MOSFET: it works as the switch in protective circuit to make sure that the voltages of two ends won’t be up and down, so that the voltage will be stable.

6）The capsulation of battery pack: PVC pyrocondensation

7）Lithium ion battery design schematic diagram of mobile payment terminal: