Can i have 3X3.7volts Nokia BL5c added?
Only if you have the Philosopher's Stone, or have achieved self sustaining cold fusion or have a notarised working over unity device.

ie you CAN add the voltages from 3 cells by placing them in series.

You can add the capacities (with certain reservations) by placing them in parallel.

BUT you cannot add the voltages and mAh capacities simultaneously.

A BL5C battery is rated at 3.7V, 1020 mAh.
 3 in series (3S) gives 11.1V , 1020 mAh nominal.
 3 in parallel (3P)  (with due care) gives 3.7V , 3060 mAh.

9 combined in 3 parallel combined strings with 3 in series per string (3S3P) gives 11.1V, 3060 mAh.

Combining identical LiIon cells in the same condition and state of charge in parallel is doable but CAN cause vent-with-flame and general excitement.

Placing a resistor of about R = V/I = 0.1V / Imax in series with each cell may help slightly and not cause too much trouble in some cases.
 eg if max current per cell is 800 mA then R = V/I = 0.1/.8 = 0.125 Ohm or about 0.1 Ohm. Suitably long and thin wiring may suffice. This resistance provides son=me voltage drop which helps balance MINOR inequalities between cells and stops a gazillion amps trying to flow if cell state of charge is mismatched when they are combined. Which should never be the case.

Charging parallel strings of series cells also has its challenges.

A laptop cell is often an 18650 LiIon rated at about 2000 mAh or more. The BL5C battery is about 1/2 a laptop's usual cell. Finding a battery with more muscle is probably a good idea.

You can get 12V, 3.5 Ah and 6V 3.5 Ah lead acid gel cells - often at  good price. (I bought some on trade special for $US5 each recently). 2 x 6V, 3.5Ah SLA batteries is the equivalent of about 6 x 18650 cells or 12 x BL5C cells. Mass and volume energy densities are far worse than LiIon but also far cheaper.

2 x 6V 3.5 Ah SLA batteries can be used to jumpstart a car with a headlight flattened battery. Amazingly. Ask me how I know :-). 3 x BL5C MAY also achieve the same result. Or not.