IEC 62933-5-3:20 23适用于BESS进行计划外修改的情况。此类修饰可涉及以下中的一个或多个: -储能容量的变化； -累积子系统的化学成分、设计和制造商的变更； -使用非OEM部件改变子系统部件， -操作模式的改变， -安装地点的变更，或 -由于安装重复使用或重新利用的电池而导致的累积子系统的变化。 任何此类修改都可能损害BESS的原始安全状态。 本文件补充了IEC 62933-5-2，涉及BESS的整体安全方面。除了IEC 62933-5-2中的要求之外，还适用本文件涵盖的要求，以满足每种情况。

IEC 62933-5-3:2023 applies to those instances when a BESS undergoes unplanned modifications. Such modifications can involve one or more of the following:
- changes in energy storage capacity;
- changes of chemistries, design and manufacturer of the accumulation subsystem;
- changes of a subsystem component using non-OEM parts,
- changes to the mode of operation,
- changes of the installation site, or
- changes in an accumulation subsystem due to an installation of reused or repurposed batteries.
Any such modification can impair the original state of safety of the BESS.
This document complements IEC 62933-5-2, which relates to the overall safety aspects of a BESS. The requirements covered by this document are applied in addition to the requirements in IEC 62933-5-2 in accordance with each situation.