Restore All-Day Power to Your ThinkPad X1 with L22D3P78 Replacement Battery Is your Lenovo ThinkPad X1 Carbon 12th Gen (21KD/21KC) or X1 2 in 1 Gen 9 (21KF/21KE) struggling with short battery life, sudden shutdowns, or failing to hold a charge? This 100% brand new L22D3P78 battery is engineered to revive peak performance. With a 56.1Wh/4800mAh capacity and 3-cell Li-ion design, it delivers stable, long-lasting powerperfect for business travel, meetings, or daily productivity.