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How Many Cells Are In A Laptop Battery?

How Many Cells Are In A Laptop Battery

Question from a reader: "How many cells are in the Toshiba Satellite M105-S3041 Laptop Battery? The battery is for a Toshiba Satellite M105-S3041 and its technical ratings are 10.8 volts 8800 mAh, Lithium Ion."

The question from the reader is a great question for it gets to the heart of battery manufacturing and begins to unravel the power of a battery. The answer is simply: 12 cells. But what does the answer mean and how does the number of cells relate to the overall value of a battery? Let’s find out…

18650 is a 3.6V cylindrical Li-Ion cell. 18650 has no memory effect (distinguish between digital memory effect) and longer storage life than NiMH battery cells. 18650 is light weight and has a high energy density. It is in effect perfect for building batteries for laptop and other portable power devices.

The additional technical specifications for the 18650 battery cell include:
Nominal Voltage Average 3.7 V – the concept of nominal voltage is that voltage range exists depending on the number of cells in the battery.
Nominal Capacity - 2200 mAh (above 2200 the stability of lithium based cells is called into question)
Max. Charging Current - 2.4 Amps Max.
Max. Discharging Current - 4.6 Amps max.
Dimensions (DxH) 18.3 mm (Max 18.4) x 64.9 mm (Max 65.1)
Weight 46.5 g (1.64 oz)
Internal Impedance: less or equal to 90 ohms
Cycle Performance is 80% of initial capacity at 300 cycles
Now as stated above the reader asked how many cells were in the Toshiba Satellite M105-S3041 Laptop Battery? The battery is rated at 10.8 volts and a capacity of 8800 mAh.

As I mentioned above the nominal voltage average is 3.7V. Some manufacturers may use 3.6V and some may use 3.7V. In the case of a laptop battery with 10.8V the nominal voltage rating used is 3.6V. Thus if we divide 10.8V by 3.6V we get 3. Thus 3 cells in a series. We also know that the batteries capacity is 8800 mAh. We know the nominal capacity is 2200 mAh. Therefore if we divide 8800 mAh by 2200 mAh then we get 4 in parallel.

Therefore we have 3 cells in series X 4 cells in parallel equals 12 cells in total.