BMW I01, Информация о продукте

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I01�High-voltage�Components
12.�Technical�Safety�Precautions
176
If�a�cell�supervision�circuit�identifies�extreme�under-voltage,�over-voltage�or�excess
temperature�at�a�battery�cell,�this�also�leads�to�a�hard�opening�of�the�electromechanical�switch
contactors�-�controlled�by�the�SME�control�unit.�Although�this�may�lead�again�to�increased
wear�at�the�contacts,�this�quick�shutdown�is�necessary�to�prevent�destroying�the�respective
battery�cells.
• Malfunction�of�the�12 V�voltage�supply�of�the�high-voltage�battery�unit:
In�this�case�the�battery�management�electronics�control�unit�no�longer�works�and�it
is�no�longer�possible�to�monitor�the�battery�cells.�For�this�reason�the�contacts�of�the
electromechanical�switch�contactors�also�open�here�automatically.
12.2.3.�Charging�the�high-voltage�battery
The�SME�control�unit�also�plays�an�important�role�in�the�charging�of�the�high-voltage�battery�with
energy�supply�from�an�external�power�network.�Using�the�state�of�charge�and�the�temperature�of
the�battery�cells,�the�SME�control�unit�defines�the�maximum�electrical�power�which�the�high-voltage
battery�can�currently�use.�This�value�is�transmitted�in�the�form�of�a�bus�signal�via�the�PT-CAN2�to�the
EME�control�unit.�The�"High-voltage�power�management"�function�coordinates�the�individual�power
requirements�and�forwards�the�total�value�to�the�electrical�machine�electronics�(and�from�there�to�the
convenience�charging�electronics).
During�charging�the�SME�control�unit�constantly�identifies�the�state�of�charge�already�reached�and
monitors�all�sensor�signals�of�the�high-voltage�battery.�In�order�to�ensure�optimal�progress�of�the
charging�procedure,�the�SME�control�unit�constantly�calculates�current�values�for�the�maximum
charging�power�based�on�these�values�and�communicates�these�to�the�EME�control�unit.�The�heating/
cooling�system�of�the�high-voltage�battery�is�also�continuously�controlled�by�the�SME�control�unit
during�the�charging�procedure�which�contributes�to�a�quick�and�efficient�charging�procedure.
12.3.�Pinpointing�isolation�faults
The�SME�control�unit�reliably�identifies�when�the�isolation�resistance�in�the�high-voltage�electrical
system�drops�below�the�specified�values.�A�fault�code�entry,�a�Check�Control�message�and,�if�required,
the�shutdown�of�the�high-voltage�system,�are�automatically�effected.�The�isolation�monitoring�in�the
SME�control�unit�alone�cannot�determine�the�actual�location�of�the�fault�in�the�high-voltage�electrical
system.�Instead,�an�isolation�fault�must�be�pinpointed�by�using�a�test�schedule�in�the�diagnosis�system.
Several�systematic�test�steps�are�required�in�order�to�determine�the�components�or�the�high-voltage
cable�causing�the�isolation�fault.
12.4.�Start-up�of�the�high-voltage�system
If�in�the�event�of�a�repair�high-voltage�components�are�removed�or�replaced,�it�is�imperative�to�ensure
that
• all�high-voltage�connectors
• all�potential�compensation�lines�and�connections�for�potential�compensation
• all�signal�connectors
• all�coolant�or�refrigerant�lines�and
• all�mechanical�connections�are�properly�connected.