Overview - BMW I01 Product Information

I01￿High-voltage￿Components
5.￿High-voltage￿Battery￿Unit
If￿the￿housing￿of￿the￿high-voltage￿battery￿unit￿is￿also￿damaged,￿for￿example￿a￿crack,￿contact￿must￿be
established￿with￿Technical￿Support￿to￿determine￿a￿suitable￿course￿of￿action.
5.2.4.￿Interface￿for￿the￿refrigerant￿circuit
It￿is￿incorporated￿in￿the￿refrigerant￿circuit￿of￿the￿heating￿and￿air-conditioning￿system￿for￿cooling￿the
high-voltage￿battery.￿In￿order￿to￿be￿able￿to￿perform￿condition-based￿cooling,￿there￿is￿an￿electrically
activated￿combined￿expansion￿and￿shutoff￿valve￿at￿the￿high-voltage￿battery￿unit.
There￿are￿two￿versions￿of￿this￿valve.￿Which￿version￿is￿installed￿in￿the￿I01￿depends￿on￿the￿equipment
without/with￿heat￿pump￿(option 4T9).￿Without￿the￿optional￿heat￿pump￿the￿combined￿shutoff￿and
expansion￿valve￿is￿hard-wired￿to￿the￿SME￿control￿unit￿and￿is￿activated￿directly￿by￿this￿control￿unit.￿The
valve￿is￿closed￿currentless,￿i.e.￿no￿refrigerant￿flows￿into￿the￿high-voltage￿battery￿unit.￿The￿valve￿only
knows￿two￿positions,￿"closed"￿and￿"open".￿The￿amount￿of￿flowing￿refrigerant￿is￿adjusted￿thermally.
With￿the￿optional￿heat￿pump￿the￿combined￿expansion￿and￿shutoff￿valve￿is￿a￿constantly￿activated￿valve.
The￿precise￿operating￿principle￿is￿described￿in￿the￿product￿information￿bulletin￿"I01￿Heating￿and￿Air-
Conditioning￿System".
The￿exact￿installation￿location￿of￿this￿valve￿is￿shown￿in￿a￿graphic￿in￿the￿chapter￿"Low-voltage
connections".￿The￿operating￿principle￿of￿the￿cooling￿system￿is￿described￿in￿the￿next￿chapter.
5.3.￿Heating￿and￿cooling￿system
5.3.1.￿Overview
To￿maximizethe￿service￿life￿of￿the￿high-voltage￿battery￿and￿obtain￿the￿greatest￿possible￿power,￿it￿is
operated￿in￿a￿defined￿temperature￿range.￿The￿high-voltage￿battery￿unit￿is￿essentially￿operational￿in
the￿range￿of￿-40 °C￿to￿+50 °C.￿These￿temperature￿limits,￿however,￿relate￿to￿the￿actual￿temperature
of￿the￿cell,￿not￿the￿ambient￿temperature.￿In￿terms￿of￿temperature￿behavior￿the￿high-voltage￿battery
unit￿is￿a￿slow-action￿system,￿i.e.￿it￿takes￿several￿hours￿until￿the￿cells￿assume￿the￿ambient￿temperature.
Therefore￿having￿the￿battery￿spend￿a￿short￿period￿of￿time￿in￿an￿extremely￿hot￿or￿cold￿environment
does￿not￿mean￿that￿the￿cells￿will￿already￿have￿assumed￿this￿temperature.
The￿optimal￿range￿of￿the￿temperature￿of￿the￿cell￿with￿regard￿to￿service￿life￿and￿performance￿is￿more
limited.￿It￿is￿between￿+25 °C￿and￿+40 °C.￿Mainly￿if￿the￿cell￿temperature￿is￿continuously￿significantly
outside￿this￿range￿and,￿at￿the￿same￿time,￿high￿power￿is￿required,￿this￿would￿reduce￿the￿service￿life
of￿the￿battery￿cells.￿To￿counteract￿this￿effect￿and￿ensure￿maximum￿performance￿at￿any￿ambient
temperature,￿there￿is￿automatic￿heating￿and￿cooling￿for￿the￿high-voltage￿battery￿unit￿of￿the￿I01.
The￿I01￿is￿equipped￿as￿standard￿with￿a￿cooling￿system￿for￿the￿high-voltage￿battery.￿For￿this￿purpose
it￿is￿incorporated￿in￿the￿refrigerant￿circuit￿of￿the￿heating￿and￿air-conditioning￿system,￿similar￿to￿current
BMW￿active￿hybrid￿vehicles.￿If￿the￿customer￿orders￿optional￿equipment￿494￿(Seat￿heating)￿for￿driver
and￿front￿passenger,￿his￿I01￿also￿has￿heating￿for￿the￿high-voltage￿battery.￿The￿heat￿effect￿of￿the
electrical￿current￿is￿used￿for￿heating￿up￿the￿high-voltage￿battery.￿This￿heating￿including￿the￿control￿is
located￿inside￿the￿high-voltage￿battery￿unit.￿At￿a￿very￿low￿ambient￿temperature￿or￿cell￿temperature￿and
with￿a￿connected￿charging￿cable,￿the￿heating￿is￿automatically￿activated￿if￿required￿in￿order￿to￿warm￿up
the￿battery￿cells.￿This￿way￿the￿otherwise￿restricted￿performance￿is￿improved￿considerably￿at￿very￿low
temperatures￿and￿the￿range￿can￿be￿increased.
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