Update: Article has been updated to more accurately reflect the previous method players would attain Battlepacks.
Battlepacks in Battlefield 1 used to be awarded to a randomly selected number of players at the end-of-the-round, those chosen would then be rewarded with a Battlepack.
But the developers have now replaced that system with one that will allow more players to have a chance to gain Battlepacks. Now, a new progress bar has been introduced at the End of Round screen that shows a player’s progress towards their next Standard Battlepack.
Playing and finishing multiplayer matches will fill up the progress bar, the amount of which is unclearly determined by how well a player does in the match. The change will allow everyone to earn Battlepacks regardless of how well they play as the meter will still move regardless.
[Source: Battlefield (Twitter), Reddit]
