"Some companies and internet-based service providers offer a battery repair, cell replacement or even a so-called battery "refreshing" service: are these solutions suitable for repairing defective batteries?"
Bosch strongly advises against "refreshing" the battery because the safety and optimum interaction with the Battery Management System cannot be guaranteed in this case.
Bosch eBike batteries must never be opened - not even if the repair or cell replacement is carried out by a third party. Opening the 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 that 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 may catch fire due to short circuiting. These dangers persist even at a later date if you continue to use the eBike battery.
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. Tests include, for example, overload tests, impact tests, short circuit tests, vibration tests and thermal tests, etc.
Even the simple replacement of original battery cells with apparently identical individual cells as part of a repair poses a threat to safety-relevant components. This would necessitate re-testing according to the safety standards described above, however these tests cannot be carried out on individual repaired batteries.
If you have any questions about your battery, please always contact your local specialist retailer, who will get in touch with our service department.