Battery Component Selection And Testing
The battery is basically something we touch every day, and there is a small battery in the mobile phone. Today we will take a look at the selection and testing of battery components.
1 Component selection criteria
1.1 Protection IC selection
● Mid-to-high end: MM3280H02, Seiko 8261AAGMD, Ricoh R5400N110FA
● Low-end: composite IC, etc.
● Special requirements of individual customers
1.2 MOSFET selection
● Mid-to-high end: Panasonic MTMC8E2A0L; AON3816, Magna, etc.
● Low-end: MOS 8205, etc.
1.3 Resistance, capacitance
● Capacitors: use TDK, MARUTA capacitor brands, and require the material to be X5R or X7R, and do not use Y5V capacitors
● Resistance: Use TDK, Yageo brand, and require better precision materials
1.4 ID resistance and NTC resistance
●The choice of the two is to configure the resistance value and accuracy according to customer requirements. NTC thermistor also needs to determine its B value, and the package form should be determined according to the PCM space and wiring requirements
1.5 Fuse and PTC
● When the customer requests to use, the fuse should be given priority to use 6A/0603 package
● There is no requirement by the customer, but when it is needed for related certification, the use of PTC or fuse must be considered.
● When the customer does not require and does not require related certification, the fuse and PTC are not used
2 The design of the protection board
2.1 PCB material
FR4 is mainly used in the selection of the material of the protection board, mainly considering factors such as fire protection grade, mechanical strength, and price. When the gold finger on the PCM needs to be exposed, it needs to be electroplated with a good-looking and wear-resistant metal layer, such as A thick gold standard gold plating thickness ≥ 0.25um B ordinary gold plating gold thickness ≥ 0.015um, hard plate copper skin thickness ≥ 1.0 ounce
Components
3 Electrical performance test standards
3.1 Requirements for measuring instruments
● Voltmeter requirements: The accuracy of the voltage meter should be no less than 0.5, and the internal resistance should be no less than 10KΩ/V.
● Requirements for ammeter: The accuracy of the meter for measuring current should not be less than 0.5.
● Thermometer requirements: the accuracy of the temperature measurement instrument should not be less than ±0.5℃.
● The current of the constant current source is constant and 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 an AC 1KHz detection method and an instrument with an accuracy of not less than 0.5 to measure the internal resistance between the positive and negative electrodes at the battery interface. Generally, the internal resistance of the mobile phone battery is ≤150mΩ. If there is a PTC battery internal resistance, it is recommended to ≤180mΩ, depending on the specific situation.
