Both lot IDs and serial numbers are both used frequently to track products throughout the receiving and sales process. However, there is an important distinction between lot tracking and serialization.
The lot id (or batch number) is a number assigned to a group of products for which are common with specific properties. There is a one-to-many relationship as many products can have the same lot ID. Batch numbers typically provide additional functionality for tracking manufactured date, expiry dates and other more detailed information. For example, a food company could make 1,000 bottles of ketchup in an 8-hour shift. Each bottle would be labels with the same lot id used to track the manufacturing date or expiry date.
Serial numbers are properties that can be different for stock items of the same product. Unlike lot ids, there is a one-to-one relationship as a unique number is assigned to a single product. No other product can exist with the same serial number. A serial number is often used on products where it is important to track warranty and service issues after a sale.