This part is a kind of semiconductor called S-8205A.

Function of this product has BATTERY PROTECTION IC.

Manufacturers : Seiko

Image and pinout :

Some of the text within the PDF file :

S-8205A/B Series www.sii-ic.com © SII Semiconductor Corporation, 2010-2016 BATTERY PROTECTION IC FOR 4-SERIES OR 5-SERIES CELL PACK Rev.1.8_00 The S-8205A/B Series includes high-accuracy voltage detection circuits and delay circuits, in single use, makes it possible for users to monitor the status of 4-series or 5-series cell lithium-ion rechargeable battery. The S-8205A/B Series is suitable for protecting lithium-ion rechargeable battery pack from overcharge, overdischarge, and overcurrent.  Features • High-accuracy voltage detection function for each cell Overcharge detection voltage n (n = 1 to 5) 3.55 V to 4.50 V*1 (50 mV step) Overcharge release voltage n (n = 1 to 5) 3.30 V to 4.50 V*2 Overdischarge detection voltage n (n = 1 to 5) 2.0 V to 3.2 V*1 (100 mV step) Ove [ ... ]

S-8205A PDF Datasheet Download