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SELF-sustained and Smart Battery Thermal Management SolutIon for Battery Electric Vehicles

Periodic Reporting for period 1 - SELFIE (SELF-sustained and Smart Battery Thermal Management SolutIon for Battery Electric Vehicles)

Reporting period: 2018-12-01 to 2020-05-31

Nowadays, no EV can accept an ultra-fast charging rate, but several automakers are working on electric cars able to accept that kind of power. SELFIE makes its biggest impact here, ensuring that the EVs, in the not so distant future, can accept this high charge rate without reduction on battery lifetime and to store the energy efficiency in their batteries with minimal losses.
The overall objective is to develop and demonstrate a novel self-sustained compact battery system, consisting of:
- A smart modular battery pack, which has excellent internal thermal conductivity properties, a refrigerant cooling system and thermal storage system (heat buffer) capable to absorb excess heat due to fast charging, and which is thoroughly insulated from the outside;
- An advanced battery thermal management system that is capable to keep the battery temperature effectively within the optimal window and to prevent overheating (and battery degradation) due to fast charging.
Importantly, it was originally intended to propose a fast-charging capability up to 180kW However, the SELFIE battery pack is based on the Fiat Doblò EV requirement which was characterized by CRF according to the use cases defined in WP1 (in D1.1) to establish the performance of the baseline reference solution (with liquid cooling).
Therefore, this results in the capability to safely handle fast-charging power up to 140 kW (5C) and to reduce the charging times to 10 min @ 140 kW (15 min @ 100 kW) as the SELFIE battery system is capable to effectively absorb the excess heat released during fast charging. In order to not affect the objectives of SELFIE, battery technology was selected to meet the fast-charging requirement. More detailed can be found in the D1.2.
The total battery system will be integrated into the Fiat Doblò and validated in test bench set-up, on a test track and the road to achieving TRL 7. And to prove that it is possible to achieve high range with a compact and affordable battery module. The specific technical objectives, main innovations and targeted key results are resumed in the following table.
In the end, SELFIE will significantly increase user acceptance of EVs by enabling fast-charging; offering significant cost reductions and elimination of range anxiety compared to other propulsion technologies.
In the period covered by the report, the work performed can be distinguished per work package:

In WP1 (CRF), a significant contribution about the definition of specification and requirements of the SELFIE system to be applied in the Doblo BEV, through the definition of electrical, thermal, dimensional and gravimetric parameters as well as providing representatives use-case scenarios to be applied during validation testing. In task 1.2 a peer review of D1.2 on cell choice for the module, looking with critical eye the different cell arrangement proposed for the SELFIE was also provided. A larger contribution has been given in WT1.3 on Concept and Test plan (whose CRF is lead beneficiary) describing which kind of test must be executed on the SELFIE system by the point of view of functional verification, lab characterization and on the road final verification.

In WP2 (LBF), with reference to WP1 and the battery selection, the first draft of the SELFIE battery system was proposed. The design considers the electrical, the thermal and mechanical aspects to fulfil the project requirements.As the SELFIE system design involves all partners, contributions have been provided by the whole consortium n terms of participation in conference calls and face-to-face meetings, too.
LBF provided a peer-review report (D2.1) in which the design and simulation of each component comprising the SELFIE battery system and the thermal management unit are detailed, such as: the battery model, the PCM plate, the cooling plates, the front-end module, the cold storage device, etc. This achievement allowed to evaluate assess the overall performances of the SELFIE pack at the system level.

In WP3 (VCC), the simulation platform derived from the GHOST project was successfully developed and will be used at the end of the project to simulate in real-time the complete thermal management system. Moreover, the specifications defined in task 1.2 were tracked to estimate the cooling needs and the impact on the battery performances. Mock-up units representing the different thermal systems (cold storage device, mass-flow limiter, etc.) were built and will be tested experimentally during the second period of the project.

In WP5 (ViF), the Hazard Analysis and risk assessment (HARA) of the system was done. In Task 5.1 (ST5.1.1) a process model concerning functional safety was created with the tool EPF-Composer. It is based on ISO 26262 the automotive standard for functional safety. The process describes a methodology for safety analysis based on the latest version of ISO°26262 and experience from completed projects. The process model contains a strategy to evaluate the safety and performance of the HV battery system. It is structured in activities and tasks. Each task has inputs, outputs, and process description. If needed, a detailed description of each step is available in the technical report (Part B).

In WP7 (I2M), the official project website was launched and represents the principal means of disseminating and exploiting the project results. Additionally, the first version of Dissemination Plan was submitted and sets the overall dissemination policy to be followed, identifying the relevant actors/target groups, dissemination means and channels and partners’ responsibilities (details in D7.2 “Dissemination Plan”).
Considering SELFIE thermal management, the main expected results are:

The integration of new components and functionalities on the vehicle which enables long-duration trips (e.g. 700-1000 km day trips across different Members states) with no more than 60-90 minutes additional travel time (for charging) and without additional degradation
impact on the FEV power train including the battery which comprises of the development of :
a new smart heat storage housing structures, consisting of smart and cost-efficient material structures allowing function integration (polymers, phase change materials (PCM) and inserts) to reduce the temperature.
a novel battery cooling plate with direct refrigerant cooling enabling a high heat transfer rate and therefore a good thermal connection from the battery to the cooling and heating system.
a novel PCM heat buffer which is dedicated for fast charging energy management.
an innovative cooling module in the front end that will increase the airflow rate. The increment of flow rate is ensured without any additional electric power, allowing a decrease in the energy consumption of the cooling module.
a cold storage device allowing the A/C system to run alternatively at two low-pressure levels. Changing the low-pressure level between 3.5 and 5.5 bars will increase the system of global efficiency.
a novel high conductive material such as gap fillers and heat pipes between the battery cells to reduce the temperature peak.

Finally, the overall efficiency increase of the new functionalities and full-size implementation and demonstration.