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Industrial Modular Battery Pack Concept Addressing High Energy Density, Environmental Friendliness, Flexibility and Cost Efficiency for Automotive Applications

Periodic Reporting for period 1 - iModBatt (Industrial Modular Battery Pack Concept Addressing High Energy Density, Environmental Friendliness, Flexibility and Cost Efficiency for Automotive Applications)

Reporting period: 2017-10-01 to 2019-03-31

The current commercial battery technology that will dominate the market for a least 10 additional years is based on lithium, an element which is concentrated in specific parts of the world outside Europe. It is known that lithium ion (Li-ion) battery technology, with all its advantages in performance, is nevertheless still far from preventing the range anxiety effect on vehicle users. Several challenges are being addressed in the state of the art at cell electrochemistry and BMS development levels but these approaches are out of the scope of this topic. The challenge is, then, to maximize the energy density of Li-ion packs through the optimization of the structural design and components of a battery pack (BP) for a given cell form factor. In this sense the strategy is to increase the energy density by reducing the weight of the BP while keeping structural integrity and easy assembly and manufacturing.
On the other hand, vehicle manufacturing is one of the most important businesses worldwide and specifically for Europe is one of the pillars of our economy, both for all the direct and indirect labor generated around automotive industry. It is now the moment to compete in the BP design and manufacturing field, where Europe has significant strengths. European industry must offer a product whose life time is optimized for the intended application and can be easily extended. Besides the cell, a BP is composed of structural materials to keep the safety of the BP, electrical components to drive the energy and power of the battery and the cooling system to thermally balance the BP. All the knowhow to design and manufacture them is available within European SMEs and large industries.
All the above mentioned energy density increase, BP cost reduction and enhancement of European SME and large industries competitiveness must be accomplished keeping in mind the impact of our activities on the environment. Thus, eco-design of the BP, environmentally friendly considerations towards the BP manufacturing process and use of automated manufacturing are addressed from the perspective of minimizing the ecological footprint of the product to be developed and improving the current method of BP parts recovery in the recycling process.
The objective of WP2 was to select commercial cells offering optimal operational parameters and boundaries enabling to accomplish the target for improving the BP energy density in iModBatt. This target should also match industrial manufacturability, modularity and recyclability objectives in other WPs. Based on the know-how and suitable facilities of the Consortium regarding chemistries used in automotive industry, commercial high energy density cells behavior were analyzed in order to fit the main goal of energy density for the proposed vehicles.
In WP3, the core pack initial design was improved to reach density and modularity targets, in order to achieve a universal modular architecture. The design considered the necessary steps to assemble, disassemble and dispatch the components of the BP in an industrial environment, considering safety, cost and environmental impact. This work package was in close contact with WP4 and WP5, where the BP cooling system and the BP industrial manufacturing means were defined simultaneously (even if WP5 was not launched, WP5 leader participated in the discussions in WP3).
The goal of WP4 was to define and develop the cooling system of the BP. This is a hybrid system composed of heat conducting elements and a heat exchanger. The devices were specifically designed for thermal balancing and included some other structural components that would support the thermal behavior of the whole system. The target of this work package was to optimize the devices closely attached to the BP, that is, the cooling plates, pipelines and heat sinks. Together with the HW development, the thermal management strategy was defined. The achieved thermal management strategy will be implemented in a currently existing BMS. Finally in WP6 this system will be integrated in each of the two available electric vehicles: Renault Zoe and e.GO Life.
WP5 started in M16 (January 2019), but just partially (T5.1) focused on the review of the overall BP design. Hence, the whole Consortium analyzed and fine-tuned the electrical, mechanical and thermal aspects of the design, especially the WP leaders.
In WP6 the main goal is to validate the mechanical and electrical functionality of the designed battery for the Renault ZOE and the e.GO Life. The main activity in the first period has been focused on the definition of the BP integration in the vehicles. To integrate the battery packs into the vehicles, a detailed integration methodology has to be defined for the Renault ZOE and the e.GO Life.
The main objectives of WP7 are to qualify the developed batteries in a regulatory and environmental way and to develop a specific and optimize recycle and/or reuse processes for the battery production aimed to electric vehicles. For that a first Life Cycle Assessment (LCA) was carried out in order to assess the environmental footprint of baseline parts (battery packs from REN and EGO, and module from TYVA) and to investigate manufacturing steps with the highest environmental impact. Ecodesign methodology was used in WP2, WP3 and WP4 to advice the best sustainable candidates solutions (li-ion cells, PCB, thermoplastics pieces). Recycling efficiency was also monitored for eco-design. In order to anticipate the optimization of the recycling/reuse of the battery pack designed in iModBatt, the state of the art was studied to determine main recycling routes for li-ion batteries in electric vehicle. A recycling calculation tool was launched to quantify recyclability.
Specifically, several advances can be identified due to iModBatt, namely related to: cell selection and combination, BP mechanical - electrical -thermal design, BP industrial manufacturing and BP recycling and second use. Most of this innovation fields will be led by industrial partners, that based on their products in the market and expertise will develop the new proposals in collaboration with the rest of partners, so that the value of European industry is enhanced.
Regarding the cell selection and combination, a methodology to select the most suitable cells and best packaging for the use case has been developed during this first period. This methodology supports in the selection of the cell reference from the techno-economical point of view and also from the environmental and recycling point of view. Additionally a combined thermo-electrical cell model that includes ageing and a simplified vehicle model can help in the definition of the BP behavior under scenarios defined by the user / customer. The methodology can be applied to any type of cells and technologies.
Even if the BP mechanical, electrical and thermal design have been customized to existing vehicles, which are already in the market (Renault and e.Go) a high degree of modularity, energy density and volumetric density have been achieved. On the other hand, since mass production processes cannot be applied for the short batch of modules and BPs that are scheduled, the weight of the BP is not optimized from the material selection point of view. However, the optimization track is clearly defined as soon as those mass production means would be available.