Does your laptop have the Lenovo Energy Management installed? You can use it to limit the battery charge on the laptop; the default should be 60% capacity. You would need to manually override it charge the battery to 100%. Here's a link to the intro to Lenovo's Energy Management 8.0 which is the latest version; it takes a while to load for some read (about 5 minutes for me).
Basically the reason to limit the battery charge is to prevent "lithium ion plating". Empirical evidence has shown that when the charge capacity in a lithium ion battery is close to 100% a chemical reaction referred to as lithium ion plating starts to occur. Lithium ions is what allows the battery to hold a charge, but when the battery is charged the lithium ions actually starts to combine together to form "plates". When this happens those lithium ions can no longer hold a charge which causes the capacity of the battery to drop. The higher the charge, the more likely this chemical reaction will occur and the faster the battery will die. This is why if a laptop has an energy / power manager installed by the manufacturer, the battery is typically limited to charge to only 60% to 80% by default. This is not a default Windows feature.
Naturally, if you need to take the laptop out of the house or the office, then you override the energy / power manager to allow the battery to charge to 100%.
Thank you hang-the9. Jaguarskx, as far as I understand from you is that I should install the Lenovo Energy Management and limit the charging to 60%-80% to increase the battery life, but my question was regarding gaming while charging the laptop at the same time whether it will affect the battery life or not.
Playing games doesnt affect anything on the battery except it consumes the battery a bit quicker when not plugged in.
So don't worry about playing games while charging or not charging....just do what you want...