You have questions about our products and our company? Then you have come to the right place!
Our FAQ picks up those questions often asked and beyond that we would like to answer further questions all around e-bike batteries and the basics of the lithium-ion technology.
Technology
How is the battery pack built up?
An e-bike battery consists of just a few components:
- Housing
- Discharging- and charging socket
- Battery Management System (in short BMS)
- Corepack
- Capacity display and button
- Temperature sensor
- Set of cables
The corepack refers to the battery pack that in turn is sub-divided into the following components:
- Cell mounting
- Lithium-ion round cell
- Cell connector
The round cells are wired up via a specially designed cell connector, which connects the round cells depending on the configuration. Example: E-Bike Vision Battery 17 Ah/612 Wh compatible with Bosch Classic: In order to achieve a 36 V nominal voltage, altogether 10 round cells must be switched in series. This results in a total voltage of 36 V (10 × 3.6 V= 36 V). The capacity is reached by parallel-switching several round cells in series. In order to achieve17 Ah, 5 round cells of the Panasonic NCR18650BL type with 3.4 Ah were used (5 × 3.4 Ah = 17 Ah). This configuration is called 10S5P → 10 x in series and 5 x parallel. In this example an overall of 50 Panasonic round cells are used.
What is a Battery Management System?
The Battery Management System (in short BMS) is an electronic control monitoring and regulating the status of the battery. It is an important part of every battery and is responsible for the necessary cell-balancing. It protects against external short circuits, operates the lithium-ion battery within the permissible voltage range and protects the battery against overheating and undertemperature. The BMS establishes the filling level and communicates with the components of the drive system.
Does cell-balancing take place in E-Bike Vision Batteries?
Yes. We use a passive cell-balancing in our products such that the voltages of the cells in series always remain identical and so that you can enjoy many kilometres with our products.
The discharge curve of lithium-ion batteries
The discharge curve of lithium-ion batteries is not linear. The voltage range is between 25 V (discharged) and 42 V (fully charged) in case of a 36 V battery. The 36 V is called a nominal voltage. During discharge, the voltage of lithium-ion batteries reduces rather fast to start with, from the achieved final charging voltage (42 V) to the nominal voltage (approx. 36 V), but from this point on it reduces hardly at all over a longer period of time. The cell voltage starts to fall very much just before a complete discharge.
Example: Discharge curve of a 18650-round cell Panasonic NCR18650A
