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4.2.2. Over-discharge protection
Two kinds of protection are used to prevent over discharge: regarding cells voltage, BMM
could open the contactor.
The two kinds of protection are:
- Cell under voltage first level: one cell voltage < 2.5V
- Cell under voltage second level (redundant): one cell voltage < 2V
4.2.3. Over temperature protection
Two kinds of protection are used to prevent over temperature: regarding module
temperature, BMM could open the contactor.
The two kinds of protection are:
- Module over temperature first level: one module temperature > 60°C
- Module over temperature second level (redundant): one module temperature
> 70°C
4.2.4. Over current protection
Some kinds of protection are used to protect battery against over current and to prevent cells
ageing by optimizing charge and discharge current.
The protections are:
- A 50A fuse inside BMM will protect battery in case of short-circuit
- A software over current protection will open contactor if current is > 55A
during 40s.
- A software protection will open contactor if current is > MAX(1.1 x IMD ;
55A) during 30s.
- A software protection will open contactor if current is > MAX(1.6 x IMR ;
55A) during 30s.
To prevent cells ageing, charge and discharge current must be optimized following IMD_C
and IMR_C values. These values are calculated depending on SOC, cell voltage, module
temperature and instantaneous current. The values are given by the BMM on CAN-open bus.