Can Bosch rechargeable batteries be opened to replace individual cells?
Bosch eBike batteries must never be opened – not even if they are being repaired by third parties. Opening the rechargeable battery always means interfering with the condition approved by Bosch and entails safety-related risks. There is a risk that the Bosch eBike battery, once opened, may catch fire during re-assembly due to crushed or incorrectly routed cables, detached components or poor quality electrical connections due to a short circuit. After opening, the tightness of the housing can no longer be guaranteed, so the ingress of water or dust can lead to damage to the monitoring electronics (battery management system) or to the cells. Here, too, there is a risk that the Bosch eBike battery could catch fire due to short circuiting. These dangers also exist at a later point in time if an eBike battery, once opened, is used again. For safety reasons, rechargeable batteries must generally satisfy the requirements of EN50604-1 and UN-T 38.3 if they are to be transported commercially. The test schedule according to UN-T 38.3 entails various safety tests on a prescribed number of rechargeable batteries that push the test specimens to their limits. These include, for example, overload tests, impact tests, short circuit tests, vibrations, thermal tests etc. Even replacing originally installed cells with single cells of supposedly identical design as part of a repair entails interference with safety-relevant components. This would necessitate re-testing according to the safety tests
described above, however these tests cannot be carried out on individual repaired rechargeable batteries.