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Battery Modular System Integrated with Conversion

Final Report Summary - BASIC (Battery Modular System Integrated with Conversion)

Executive Summary:
SAFT has studied and listed all the relevant architectures to fit with BASIC environment.The mains inputs data taken into account for the design are:
- Safety: redundancy, segregation impact: electronic choice
- Mission profile: needs in energy and in power impact: cells choice
- Weight impact: material choices (electronic, cells, mechanical)

The preliminary architecture has been defined and does constitute a basis for a future work.

Project Context and Objectives:
Traditionally, aircraft power system use passive power converter coupled with NiCad battery to provide power 28Vdc buses from main AC network. This solution is very mature, but power quality from this architecture is low
and impact avionics loads designs and overall system reliability.
Recent progress in power electronics and lithium –ion batteries allows higher power density compared to traditional passive approach. The new solutions allow considerable performances enhancement and weight/volume savings (feeder, loads...) and better reliability at aircraft level.
Management of lithium battery charge and discharge imposes multiples protections in order to insure a proper behavior during all possible scenarios and to ensure safety, even during abusive conditions. No break power transfer coordination is also a challenge at architecture level.
The main objectives of this study is to optimization the ratio weight / volume (at system level) of active power conversion system coupled with li-ion energy storage, including mutualisation of function such as battery charger and TRU. This optimisation will also improve battery expected life, keeping the functionality of a no break Power transfer 28Vdc.
In addition, this project can demonstrate benefits of a modular battery system concept, combining battery modules to subsystems and systems on demand. This leads to a high flexibility and interchange ability of battery modules.

Project Results:
This study lead to the identification of 4 different architectures :
1 NBPT Battery classified as DAL A equipment with integrated charger
2 NBPT Battery classified as DAL A equipment without integrated charger
3 Battery classified as DAL B equipment
4 Battery classified as DAL C equipment.

The 3rd architecture has been chosen to launch a pre study.
the battery system is designed in two main blocks, the first one is the cover (electronic cover) which implements electronics part and cells module which implements the cells pack.
Complete segregation between the cells module and the electronic cover is integrated, in order to insulate the power cells and electronic (safety aspect / thermal aspect).
• Separation between the different functions (electronic functions, cells functions): modular battery to reduce the assembly time, the easier reparation
• Insulating plate is implemented on electronic cover in order to avoid:
o all risks about internal intrusion (example: screws, shock linked to external tools (screwdrivers...)) during manufacturing and transportation between Saft and Industrial Supplier of the electronic cover
o None electronic components or mechanical parts can fall in the cells pack in order to reduce the risk about short circuit with the cells

Further details are available in the deliverables.

Our request to postpone the end of the BASIC activities was not accepted by the CLEANSKY Commission and thus SAFT was not able to achieve the activities.

Potential Impact:
This interruption of project has slow down the development toward an optimized solution for CLEANSKY. However SAFT is convinced about he interest of such a integrated solution. SAFT is looking forward to participating to a future project with such objectives.

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