There are 2 types of batteries for power banks. One is 18650 cylindrical lithium batteries; the other one is polymer lithium batteries. Generally, the polymer one is better than 18650 lithium batteries in terms of safety performance. However, the cost is relatively high. For 18650, the popular capacities are 2000mAh,. An excellent PCB circuit board may cost tens of RMBs, while ordinary circuit boards often cost more than RMB10. A superb circuit board allows the mobile power supply to exert its. At present, a USB cable with 8 plugs is the mainstream on the market. The wholesale price is between RMB4.5 and RMB6. And the packaging is between RMB1.5 and RMB2.5. Therefore, the. Most power bank cases are made of ABS+PC materials. The cost of a steamed bun-sized shell costs between RMB5 to RMB7 (additional RMB1 if with LED lights). Above, the shell is. Based on the fact that 4 workers assemble 1000 sets of portable power, plus wages, rent, water, and electricity, the processing cost should be between RMB1.50 yuan and RMB3.50 per unit.