Overview
This project aims to the development at an initial industrial level of an advanced, lithium ion battery for efficient application in the sustainable vehicle market. The basic structure of this battery involves a lithium-metal (tin)-carbon, Sn-C, alloy anode, a lithium nickel manganese oxide, LiNi0.5Mn1.5O4, cathode and a ceramic-added, gel-type membrane electrolyte. This battery is expected to meet the target of the topic that calls for innovative developments of lithium-based, automotive energy storage technologies improving energy density, cycle life, cost, sustainability and safety. To confirm this expectation, a strong European consortium exploiting the complementary experience of various interconnected unities, involving academic laboratories and industrial companies, has been established.
It is expected that these combined efforts will lead to the industrial production of a battery having an energy density of the order of 300 Wh/kg, a cost considerably lower than batteries already on the market, as well as having a higher environmental compatibility and having a highly reduced safety hazard. In synthesis, this project compares well with others in progress worldwide for the development of lithium batteries directed to an efficient application in the sustainable vehicle market.
The academic partners will address the work on the optimization of the basic, electrochemical properties of the electrode and electrolyte materials, while the industrial partners will focus on the determination of battery key aspects, such as:
i) the value of energy density under a large size capacity configuration,
ii) the definition of the safety by abuse test procedure protocols,
iii) the overall cost,
iv) the environmental sustainability and,
v) the recycling process.
The work will be conducted according to the following steps:
1 -Management: Set-up of an efficient management structure with clear rules for decision-making and administrative support on financial and administrative matters.
2 -Scientific coordination: Monitoring of the project progress compared with the planned activities.
3 -Optimization of electrode materials: Synthesis refinement of the electrode materials and the realization of optimized anode and cathode configuration.
4 -Optimization of electrolyte: Analysis of morphology, the molecular interactions, and the composition of the membrane and the electrolyte solution from the molecular scale and upward in order to improve performance and safety as well as to adapt the synthesis procedure for scaling-up.
5 -Scaling-up of materials preparation: Scaling-up of processes for the preparation of the key materials (cathode, anode, and electrolyte).
6 -Process development for preindustrial cell manufacturing: Development of electrode formulations and electrode manufacturing processes of new electrode materials, formulation and processing of cells for tests under EV/HEV application conditions and characterization of cell properties.
7 -Safety improvement: Development of a better material to remove unwanted gas formed during the normal cell operation to maintain the internal pressure of the devices under a controlled value, coherent with a flawless cell functioning.
8 -Test of performance and safety of project cells and batteries: Testing of cells in abused conditions (electrical, mechanical and thermal tests) and interpretation of test data and recommendation on safety and life time on cell level.
9 -Recycling of production waste and end-of-life Li-ion batteries: Recycling of production waste and end-of-life Li-ion batteries and implementation of eco-design procedures.
10 -Battery system integration: Definition of a manufacturing process f
Funding
Results
- Optimized anode configuration - proposed Sn–PMCMT is an ideal candidate anode for high-performance Li-ion batteries able to operate in a wide array of operating conditions.
- Optimized cathode configuration - Electrochemical tests confirm the high reproducibility of the developed process. The optimized electrodes were implemented in the final cells.
- Optimized electrolytes
- Development of the electrolyte solution - To optimize the stability and low temperature behaviour of the organic electrolyte solution we suggest using a 1:1:3 mixture of EC:PC:DMC. This solution can also be combined with LiBOB. We showed that the 1:1:3 EC:PC:DMC solution doped with 0.7M of LiBOB is the best choice together with the APPLES electrode materials SnC (pre-activated) and LNMO (uncoated).
- Optimization and characterization of gel polymer electrolytes - The gel casted membranes overall show good performance in combination with the APPLES anode and cathode materials, both with the new organic solvent based and the ionic liquid based electrolytes. Using the optimized conventional electrolyte solution we showed the desired functionality of LiBOB forming a protective passivating film during the first cycle, seen through the presence of a peak at around 1.7 V during the first cycle in the electrochemical tests.
- Materials scaling up
- Cathode Material LMNS - A high current capable double side coated cathode has been developed with this material and with optimized loading, showing that cathode material scale-up could be finished successfully before schedule.
- Lithium metal powder - The scale-up of the lithium metal powder for pre-lithiation purposes within the project had been completed. Lithium powder was produced and supplied to the partners.
- Anode material tin/carbon composite - the scaled Sn/C anode material was optimized with respect to its tin content and particle size and supplied to the partners for electrochemical characterization and cell manufacturing.
- Scaling-up of materials preparation/polymer electrolyte membranes - Precursor membranes were cast and sent to the partners for performance tests and cell manufacturing.
- High performance getters with high absorption capacity - the gases formed by cycling APPLES-type cells are mainly CO2 and H2. It is believed that a getter able to sorb one or both of these gases could help to control the internal pressure, enh
Technical Implications
The research and innovation proposed by the APPLES project contributes to the strengthening of the competitiveness of the European industry of automotive battery and electrochemical capacitors in global markets through the scaling up to an industrial level of a lithium ion battery based on a chemistry totally new in respect to that exploited the common versions of these power sources.
This new chemistry involves the use of lithium-metal alloy (Sn-C) as anode (with a practical specific capacity, i.e. 500 mAh/g, higher than that of the common graphite), a lithium nickel manganese oxide spinel, LiNi0.5Mn1.5O4 as cathode (with an operational voltage, i.e. 4.5V vs. Li higher than that of the common lithium cobalt oxide) and a composite, gel-type membrane as polymer electrolyte (with expected reliability and processability higher than those of the common organic carbonate solutions).The high capacity of the anode, combined with the high voltage of the cathode, allowed obtaining a consistent enhancement in the energy density of the battery.
The final Apples cell under optimal conditions may reach 57.2 Ah at a weight of 865 grams and a nominal voltage of 4.7 Volts. This is equivalent to an energy density of 310.7 Wh/kg. The material cost is estimated to 13.8€ per cell with uncertainty in cost of the active electrode material. The total production cost including electrode production, assembly and waste management is estimated to 30.7€ per cell, excluding labor. An energy optimized battery pack has been designed using the APPLES industrial size cell. Battery dimensioning in terms of power and energy needs, has been performed by simulating the NEDC European drive cycles. The resulting battery to supply 200 km of driving distance was a 236 kg battery with 176 cells divided into two battery packs comprised of 88 cells each. The nominal voltage was designed to 413.6 V and the total capacity of the system 114.4 Ah of which 89.2 Ah were usable. The usable energy performance reached 156.6 Wh/kg where 64.6% of the system mass consist of cells. These favorable aspects resulted in an overall cost reduction at system level of 100 €/kWh. This is well below the costs indicated at the beginning of the project, which was 150 €/kWh.
The determination of the effective impact of this battery confirmed its capabilities when scaled-up to a demonstrative industrial size. In fact, it was demonstrated: i) the effective value of energy density under a high capacity configuration and the feasibil
Other results
In terms of safety, the replacement of the low vapor pressure, flammable liquid electrolyte with a more reliable, polymer membrane, consistently reduced the safety hazard. In addition, the replacement of the toxic cobalt-based cathode with an environmentally compatible nickel-manganese compound improved the sustainability of the new demonstrative battery.