Label: Lithium battery
1 component selection criteria
1.1 Protection IC Selection
●High-end: MM3280H02, Seiko 8261AAGMD, Ricoh R5400N110FA
●Low end: composite IC, etc.
●Special requirements for individual customers
1.2 MOSFET selection
● High-end: Panasonic MTMC8E2A0L; AON3816, Magna, etc.
●Low end: MOS8205, etc.
1.3 resistance, capacitance
● Capacitor: Use TDK, MARUTA capacitor brand, the required material is X5R or X7R, and the capacitor of Y5V material is not used.
●Resistance: Using TDK, Guoju brand, requires better precision material
1.4ID resistance and NTC resistance
●The choice of the two is to configure the resistance value and accuracy according to the customer's requirements. The NTC thermistor needs to determine the B value. The package should be determined according to the space and wiring requirements of the pCM.
1.5 fuse and pTC
● When the customer requests to use, the fuse should be given priority in the 6A/0603 package.
●The customer does not require it, but when it is needed for the relevant certification, you must consider using pTC or fuse.
● Do not use fuses and pTC when there is no requirement from the customer and no relevant certification is required.
2 protection board design
2.1 PCB material
FR4 is mainly used in the material selection of the protection board, mainly considering factors such as fire rating, mechanical strength and price. When the gold finger on the pCM needs to be exposed, it is necessary to plate a metal layer with good appearance and wear resistance. For example, the standard gold plating thickness of A thick gold is ≥0.25umB, the thickness of ordinary gold plating gold is ≥0.015um, and the thickness of hard copper skin is ≥1.0ounce.
3 electrical performance test standards
3.1 Measuring instrument requirements
● Voltmeter requirements: The accuracy of the meter for measuring voltage should be no less than 0.5, and the internal resistance should be no less than 10KΩ/V.
● Current meter requirements: The accuracy of the meter for measuring current should be no less than 0.5.
● Thermometer requirements: The accuracy of the meter for measuring temperature should be no less than ±0.5 °C.
● The current of the constant current source is constantly adjustable, and the current change should be within ±1%.
●The voltage of the constant voltage source is adjustable, and the voltage change should be within ±0.5%.
3.2 internal resistance test
Test method: use the AC1KHz detection method and the instrument with the accuracy of not less than 0.5, measure the internal resistance between the positive and negative terminals of the battery interface. Usually, the internal resistance of the mobile phone battery is ≤150mΩ. If the internal resistance of the battery is pTC, it is recommended to be ≤ 180mΩ, as the case may be.