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High energy density modular batteries for a sustainable construction industry

Periodic Reporting for period 2 - WATTELSE (High energy density modular batteries for a sustainable construction industry)

Okres sprawozdawczy: 2022-02-01 do 2023-01-31

The concept of WATTALPS’ batteries has been maturing since 2015. It was born from the meeting of 3 people making the same observation: there is no satisfying offer of high-performance and modular batteries for the electrification of vehicles in general, and industrial vehicles in particular. Immersion cooling is the key to bring high performance batteries to very demanding markets such as off-road vehicles. Indeed, users of these machineries, e.g. construction companies, are facing highly demanding needs in term of autonomy, productivity, operation cost and investment costs. The trade-off between all these parameters causes a lot of construction machineries to be still operated with diesel engines.

The objective of WATTALPS is to build a cleaner industry with a great respect of citizen needs (pollution, noise) and Earth health. It is embodied by strong commitments like offering a second life and recycling 100% of the lithium batteries sold by the company.
2.1 Build a prototype reaching wanted specs: based on former experiences some experiments have been conducted to acquire a good understanding of immersion cooling trends and define needed safety barriers; in-depth FMEA studies as well as fault tree analysis have been conducted at product and process level. Then a new module Gen3 has been designed and first prototypes able to support 800V systems have been built. Peripheric parts such as junction box and thermal system have also been developed in order to use the same core design and reduce specific development costs. In parallel an in-house BMS (Battery Management System) has also been developed according to automotive best standards (ISO26262) to ensure a high level of reliability (ASIL B/C). Battery prototypes and more than 120 pre-series modules have been produced to achieve the complete tests and qualification plan. As WATTALPS commits to offer a second life to its battery modules when possible it has designed and prototyped a solution of energy storage integrating qualified second-hand WATTALPS modules. As a consequence a Worksite electric generator (powerbank) demonstrator has been built and shown at Bauma fair in Munich (Germany). This prototype has demonstrated immediate interest as it can also be equipped with brand new modules offering the opportunity to charge electric machines on city or isolated worksites.

2.2 Build a pre series operational process : series production and control tools have been modified for Gen3 design and new tools have been created. A complete production line for batteries have been set up with particular attention to quality and safety controls.
A particular attention has been paid to process control and traceability which are key factors for success for such premium batteries.

The 3-buildings plant has been developed to ensure mass production up to 6 500 modules / year in 2 shifts with current equipment. Double production capacity can be achieved within 6 months by adding new equipment in the same buildings.

2.3 Obtain a full certification in Europe :
WATTALPS got the ISO9001:2015 certification without any major or minor non-conformity after AFNOR audit in December 2022. This certification is often required by major off-road machines manufacturers, but it has also helped the company to set a strong organization able to adapt to high requirements of the more demanding customers.
WATTALPS has also implemented a complete program to test and qualify its products according to UN 38.3 IEC 62619 and ECE R100rev3. A video summarizing the past tests is available at :
This campaign has been very successful and prove the high level of robustness and safety of WATTALPS lithium batteries.

2.4 Build proof of concepts and register feedbacks :
In collaboration with CETIM, a french reference in terms of technology, a Yanmar Vio26 mini-excavator retrofit including WATTALPS solution has been designed, built and tested by end users.
Measurements and comparison with diesel version have demonstrated the effectiveness of the 20kWh full electric solution in terms of power and autonomy performances.

Equipped with fast and normal charging as well as with a heater this excavator demonstrates the high potential of immersion cooling solutions.
First of all as lithium batteries are considered as being dangerous goods WATTALPS paid and pays a lot of attention to the risk of harming the environment during the WATTELSE project and has implemented the countermeasures to avoid doing so.

A study has been led with a company specialized in carbon measurement which concluded that each WATTALPS module enables the avoidance of 1.27 tCO2e.
The implementation of the reconditioning of batteries for second life applications will add to this the avoidance of an additional 1.13 tCO2e per reconditioned module.

According to WATTALPS’ Business Plan more than 125,000 modules will be produced within the next five years enabling the avoidance of 158,750 tons of CO2e.

WATTALPS has also obtained the Solar Impulse label in November ‘22 proving its solution to be very efficient both environmentally and financially speaking.
battery integration in excavator 2_2
module Gen3
battery integration in excavator 1_2
battery integration in powerbank
excavator working