TSS-ANL Cooperation

PHEV Aftermarket Conversions

Between July 2008 and December 2009 a cooperation program between TSS and Argonne National Laboratory (ANL) on PHEVs was carried out. The programmatic objective was to promote PHEV technology by developing a common understanding of the key issues/barriers and sharing or jointly developing ‘best-practice’ methodologies and tools to support PHEV development. ANL also supported the MobilEL – project (run by Fortum and the City of Stockholm) with data collection systems.

Five Toyota Prius II owned by Göteborgs Gatu AB were converted with aftermarket PHEV conversions in a joint activity between TSS and Göteborgs Gatu AB. The first Prius was converted in the UK by Amberjac Projects LTD. The other four conversions were made in Gothenburg by A123 Systems.

The aftermarket conversions do not alter with the OEM Prius controller, meaning that pure electric driving is possible up to 47 km/h after which the engine is started. However, the engine can be turned off at higher speeds if the power demand is low (e.g. moderate accelerations on a road with no inclination).

The aftermarket PHEV conversions have been used in a number of demonstrations as well as in winter testing activities and in studies performed by Swedish automotive OEMs. The vehicles are driven on a daily basis (by employes within the City of Gothenburg) and are also used for data collection.

Comparison between aftermarket battery systems used and the Prius OEM battery

Lessons learned

In general the converted PHEVs have functioned but out of the two aftermarket PHEV conversions evaluated in the program, the A123 Systems/Hymotion solution is concluded to be the most robust solution with best quality. No major faults or problems have been reported with these conversions.

Some of the experiences drawn from the use of the vehicles are presented below:

• Replacing the OEM battery with a new one is a complicated interference with the vehicle. To install an extra battery in parallel with the OEM battery is a more desirable solution since It is an easier installation with less intrusion in the vehicle; The PHEV functionality may be turned on and off as desire; It is easy to reset the vehicle to a regular Prius again (basically the extra battery is removed).
• The communication between the conversion battery and the vehicle can sometimes cause annoying situations for the driver, e.g. a page change on the energy monitor screen.
• Data collection using the internal Amberjac log system or Kvaser Memorators is fairly straight forward. However, one draw back with the internal logger is that its time is reset every time the 12 V battery is disconnected.

	Attachment	Type	Size
	tss_anl_phev_cooperation_program.pdf	pdf	5.85 MB