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Battery safety certifi cation
EV manufacturers can shorten time-to-market with the help of an off-the-shelf,
customizable automotive ISO26262 ASIL C compliant BMS platform
For electric passenger
vehicles, full compliance with
international safety standard
ISO26262 at ASIL C level is
gradually becoming an absolute
market requirement. Many other EV
markets also look to ISO26262 to
ensure functional safety of battery
driven applications. Since the
battery management system (BMS)
is at the core of ensuring safety of
the battery pack, it is imperative that
a BMS is fully ISO26262 compliant
and preferably also certified by an
independent body. Yet, currently
only a few BMS in the market are
ISO26262 compliant and
certification is rare because the
work involved is very time
consuming, di icult and expensive.
Lithium Balance experienced this
when they developed the ISO26262
ASIL C compliant n-BMS platform.
However, in the past two years the
company has made the investment
to get the next version of the n-BMS
fully certified by an external
accredited body.
The certification process involves
more than 100 critical reports to
be analyzed and verified by the
external body as well as a series
of on-site audits.
Besides analysis during the
design stage, such as hazard and
operability (HAZOP), fault tree
(FTA), failure modes and e ects
(FMEA), failure modes, e ects and
diagnostic (FMEDA), this
certification process also looks at
the entire life cycle of the BMS
through the production and service
stages of the product.
In a strategic co-operation with
Ansys – a leading software company
within automotive safety analysis
– Lithium Balance has established
a model-based approach with a
high level of consistency, traceability
and e iciency of the automotive
functional safety analysis.
The LiBAL n-BMS platform is a programmable ISO26262 certifi ed battery management system
The ISO26262 ASIL C compliant
hardware design includes a 32-Bit
RISC floating-point and dual core
CPU on the master, but the n-BMS
o ers the choice of several slave
boards to suit di erent customer
applications such as managing
di erent number of cells per slave,
di erent kinds of connectors or form
factors. Slave boards can also be
customized to customer needs.
A groundbreaking feature of the
ISO26262 ASIL C certified n-BMS
platform is an open API that allows
the customer to include their own
software code without jeopardizing
the ISO26262 certification. This is
achieved by separating the n-BMS
software into two separate layers.
The Base Layer Software (BSW)
contains all hardware drivers and all
of the safety critical functions.
166 // January 2020 // www.electrichybridvehicletechnology.com
The BSW is part of the ISO26262
certification and cannot be
customized by the customer.
However, this is possible in the
Application Layer Software (ASW)
that contains the non-safety critical
functions such as SoX algorithms.
The two software layers are
separated by an open API interface
layer to make the ASW
programming and its connection
to the BSW layer seamless.
The n-BMS comes with a
complete and configurable ASW
package of functionality from
Lithium Balance. However, via the
open API the customer can
supplement or replace the existing
ASW functionality with their own
custom and proprietary algorithms
and battery models through the
open API without jeopardizing
the ISO26262 certification of the
platform. This customization can
be carried out using the MATLAB
toolbox and Simulink codes for fast
and e icient high-level, modelbased
programming.
The solution o ers customers an
o -the-shelf automotive ISO26262
ASIL C compliant BMS platform,
that can be configured and
customized by the customers
without having to go through the
time-consuming and expensive
ISO26262 certification process. EV
manufacturers can therefore shorten
time to market, while at the same
time ensuring the functional safety
in its battery pack.
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visit: www.magupdate.co.uk/PEHV
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