Driving sustainability in public transport: boosting range with the development of a modular retrofit kit for battery electric buses. 

Project name: Development of a modular retrofit kit for battery electric buses to increase their range through self-sufficient supply of auxiliary consumers with customized fuel cell systems
Project duration: 01.09.202231.08.2025
Funding ID: 03EN5021C

Location: Aachen Germany
Project sponsor: Projektträger Jülich (PtJ)
Project leader: AE Driven Solutions GmbH
Grantor: Bundesministerium für Wirtschaft und Klimaschutz (BMWK)

Research objectives

Objective 1

Development of a cost-effective modular fuel cell system to increase the range of retrofitted electric buses through self-sufficient supply of auxiliary consumers

Objective 2

Identification of cost potentials at the system and integration level and development of a solution to reduce production costs

Objective 3

Validation of the development results through functional tests in a real environment and individual approval of the bus with the traction battery and the fuel cell system for operation

Objective 4

Use of the demonstrator bus in research and teaching at RWTH Aachen as well as for training and further education purposes at ASEAG


Identifying the Project’s Challenge

Public transport is a central component of future mobility concepts, both in urban and rural areas alike. Buses, with their high mileage and predominantly diesel-powered drives, contribute significantly to air and noise pollution, as well as high fuel costs during operation. The conversion of the diesel-powered bus fleet to electric bus technologies is crucial for sustainable urban mobility. 

Despite progress in battery technology, batteries currently and in the foreseeable future remain a limiting factor for range due to their energy density. Increasing battery capacity results in higher costs and weight, and batteries lose usable capacity due to various degradation mechanisms. 

This project addresses the high energy demand of main and auxiliary consumers in electric buses, which leads to continuous degradation of battery capacity and reduced operating time. Fuel cell technologies can extend the service life of electric buses, which can be hybridized with a fuel cell system at low cost. 

PEM Motion’s Approach

As part of the project, an 18-metre articulated bus will be put into operation and tested in real-life conditions for one year. Based on requirements analysis, the technical system and component design will be carried out, and a fuel cell system and battery system will be developed. The electrical/electronic architecture and control strategy will also be designed. After homologation, testing, and validation, the bus will go into real operation. 

PEM Motion is responsible for designing the battery system as a replacement for the defective battery and homologation of the bus. 

What Has Been Achieved So Far?

So far, requirements have been recorded, and the first concepts have been developed and evaluated with project partners. This information was used to identify, evaluate, and select possible suppliers for the new battery system and temperature management system. The design of the fuel cell system has been initiated, and the specification started.

in collaboration with


Contact Us

Aleksej Senger



PEM Motion Seminar at the
11th Electric Vehicle Production Days

System Development in the Automotive Context

Date: October 27th, 2023
Language: German

PEM LV Battery Module

General Specifications

+Wide range of parallel cells configurable

+Welding method: Spot welding

+Projected nickel design

+Customized nickel tab

+Manufacturing partners in Mexico, Germany, Poland and China

+Short time to market

+Individual packaging can be designed

+Advanced interconnect by terminal connection


+Designed with certified cells according to:

+IEC 62133
+UL 2580

Personalized configuration