The factory information of the storage tank is included by engraving the combination of numbers and English letters on the lower front of the battery. Such as 7KZ16B2 of Valta. Details are as follows:

1. The first digit is an Arabic numeral, generally one of the 10 digits in 0123456789. 7 in the above example indicates that the production year is 2017;

2. The second digit is a letter. It is generally one of the 12 letters in ABCDEFGHJKLM, where I is the same as 1, which is easy to be misunderstood, so it is removed. The production months of the battery are January, February and December in alphabetical order. K in the above example indicates that the production month is October;

3. The third digit is a letter, representing the manufacturer of the battery. C represents that the manufacturer is Chongqing; Z represents the manufacturer in Zhejiang.

4. The fourth and fifth digits are Arabic numerals, representing the production date of the battery. In the above example, 16 means the production date is the 16th;

5. The 5th and 6th digits are the combination of letters and numbers, which are the batch of the battery produced by the manufacturer; In the above example, B2 represents the manufacturer's production batch.