By October,the first batches were distributed to health care workers, pregnant women,young people and those with underlying medical conditions.

VOA: standard.2009.12.25

Charge is quantized. In other words, it comes in batches of a certain unit.

电荷是量子化的，换句话说，它一批一批的以单位形式出现。

麻省理工公开课 - 固态化学导论课程节选