IEC TS 61044:2021（e）涵盖了铅酸牵引电池的机会充电，即利用工作期间的空闲时间来增加充电状态（SoC），从而延长铅酸牵引电池的日常工作周期，同时避免过大的放电深度。 本文件规定了当蓄电池制造商未提供替代具体操作程序时，排气式和阀控式铅酸牵引蓄电池的机会充电使用要求。

IEC TS 61044:2021(E) covers opportunity charging of lead-acid traction batteries, i.e., the use of idle time during a working period to increase the state of charge (SoC) so as to extend the daily working period of a lead-acid traction battery while at the same time avoiding an excessive depth of discharge.
This document specifies requirements for the use of opportunity charging of lead-acid traction batteries of vented and valve regulated types when the battery manufacturer has not provided alternative specific operating procedures.