It’s a little hard to find out the date code of Sony 18650 battery, because it’s hidden in a long string of codes.

As shown on the pictures, there’re 5 digits counting backwards on the second line.

1. The first digit = Year (A = 1992…, J = 2001, K = 2002, L = 2003, M = 2004, N = 2005, O = 2006, P = 2007, Q = 2008, R = 2009, S = 2010, T = 2011, U = 2012, V = 2013, W = 2014, X = 2015) .

2. The second digit = Month ( A = Jan., B = Feb., C = Mar…..J = Oct., K = Nov., L = Dec.).

3. The third and the fourth digits = Day (01, 02…..29, 30, 31).

4. The fifth digit = Electrode history ( A, B, C….X, Y, Z).

On the picture, the date code of the Sony 18650 battery is 2014.01.24.