WMG is running a special three-day Battery School at its Energy Innovation Centre from 28th- 30th October for industry personnel.
WMG battery experts will facilitate a mix of lectures and practical hands-on-sessions, with the intention of inspiring the next generation of engineers into battery related careers, crucial for the UK’s electrification sector.
The lectures will cover areas including manufacturing Lithium batteries, module and pack design, electrical testing and ageing, manufacturing systems, safety and abuse testing, forensic characterisation and battery end of life.
Meanwhile the practical lab sessions will focus on electrode mixing and coating; coin cell fabrication; cell module and pack testing; and forensics.
Find out more and book your place here.
One of Europe’s largest science festivals is coming to town between September 10th and 13th.
With a schedule comprising more than 100 free events, activities and performances, the British Science Festival will “transform the region into a celebration of science and culture”.
The festival will feature talks from a selection of WMG experts, including Erik Kampert - Senior Research Fellow, Dave Greenwood – Professor of Advanced Propulsion Systems, Mark Williams – Professor of Metrology and Alan Chalmers – Professor of Visualisation.
Held in partnership with the University of Warwick, the programme highlights local strength in digital technologies, smart cities and the future of energy and healthcare.
There’s a special emphasis on the fun, thought-provoking, and societal aspects of science to show how it’s not just confined to laboratories, but something that’s all around us.
Plus, there will be a special filming of The Sky at Night: Question Time with Dr Maggie Aderin-Pocock and Professor Chris Lintott.
Other highlights include interactive experiences like a live 3-D psychedelic show and festival carpool in a driverless pod, discussions on how ‘gaming becomes gambling’, how AI could revolutionise cancer treatment, and how to tackle food poverty with food writer Jack Monroe.
Not to mention, a mud kitchen and tea-blending for adults and a takeover of Coventry’s FarGo Village with comedy, artistic workshops and an escape room.
As part of a Circular Economy for electric vehicle battery systems, as the number of such vehicles increases rapidly, the need to find the best way to reuse and recycle vehicle batteries becomes just as intense.
In partnership with Jaguar Land Rover, Future Transport Systems and Videre Global, researchers at WMG, University of Warwick, have found a way not just to recycle those used batteries, but repurpose them as small energy storage systems (ESS) for off grid locations in developing countries or isolated communities.
The repurposed units, each containing approximately 2kWh of energy capacity, will be able to power a small shop, a farm holding, or multiple residential homes.
WMG’s Professor James Marco who was lead researcher on the project said:
“When an electric vehicle’s battery reaches the end of its useful life it is by no means massively depleted. It has simply reached the end of its useful life in a vehicle.
"It is generally accepted that an EV battery has reached end of life when its capacity drops to 80% of a fresh battery. While this is no longer enough to satisfy drivers, it remains immensely useful for anyone who seeks to use the battery in a static situation.”
While such partially depleted batteries remain potentially very useful to other users there are still challenges to overcome, particularly to ensure that they can be used reliably, sustainably, and cheaply in remote locations. These challenges include:
· How to protect the lithium-ion cells from over-charge and discharge
· Can the ESS be made compatible with a variety of other used battery cells and modules from other manufacturers
· How to keep it low cost and easy maintenance, while providing an interface that is easy to use and understand
The WMG team, at the University of Warwick, set about overcoming these challenges with the help of the WMG HVM Catapult and Jaguar Land Rover who supplied batteries and components from the Jaguar I-PACE, their first all-electric performance SUV. The team designed a new Battery Management System (BMS) and packaging that allowed them to create a working and easily portable prototype ESS which included:
• The use of standard low cost components for control, communication and safety functions. All parts were either sourced from the JLR service department or were low cost components purchased from any electrical retailer.
• The ability to use different modules that could be interchanged within the 2nd-life system without having to recalibrate the whole BMS
• Enough energy for a small shop, farm holding or multiple residential homes
• Multiple 12V DC sockets and 5V USB charge ports
• The ability to have the 2nd –life module charged via reclaimed laptop chargers
• Simplified control system for easy integration and deployment
Professor James Marco continues:
“This is a great result that not only provides a highly efficient repurposing solution for automotive batteries but which could also change lives in remote communities. We are now looking for support to allow these new units to be further developed and tested in remote or off grid locations.”
The research project was part of the Innovate UK funded Project: 2nd hEVen (2nd-Life Energy Storage Systems) and is supported by the WMG High Value Manufacturing (HVM) Catapult.
WMG is pleased to announce that its Battery School is now officially supported by the Faraday Institution.
In its role as the Electrical Energy Storage APC Spoke, WMG’s battery experts together with guest lecturers facilitate a mix of presentations and practical hands-on lab sessions covering electrochemistry, applications, future technologies, manufacturing, safety, testing, forensics and battery end of life.
The new collaborative Battery School was officially opened by Neil Morris, CEO of the Faraday Institution, with the first session held for 25 PhD students and future battery engineers, in June.
The Faraday Institution is the UK’s independent institute for electrochemical energy storage science and technology, supporting research, training, and analysis. It brings together scientists and industry partners on research projects to reduce battery cost, weight, and volume; to improve performance and reliability; and to develop whole-life strategies from mining to recycling to second use.
The Battery School is situated at WMG’s Energy Innovation Centre – the largest facility of its kind in the UK. Find out more about the Energy Innovation Centre here.
Researchers at WMG at the University of Warwick have found that use of inductive charging, whilst highly convenient, risks depleting the life of mobile phones using typical LIBs (Lithium-ion batteries)
Consumers and manufacturers have ramped up their interest in this convenient charging technology, abandoning fiddling with plugs and cables in a favour of just setting the phone directly on a charging base.
Standardisation of charging stations, and inclusion of inductive charging coils in many new smartphones has led to rapidly increasing adoption of the technology. In 2017, 15 automobile models announced the inclusion of consoles within vehicles for inductively charging consumer electronic devices, such as smartphones – and at a much larger scale, many are considering it for charging electric vehicle batteries.
Inductive charging enables a power source to transmit energy across an air gap, without the use of connecting wire but one of the main issues with this mode of charging is the amount of unwanted and potentially damaging heat that can be generated. There are several sources of heat generation associated with any inductive charging system – in both the charger and the device being charged. This additional heating is made worse by the fact that the device and the charging base are in close physical contact, any heat generated in one device may be transferred to the other by simple thermal conduction and convection.
In a smartphone, the power receiving coil is close to the back cover of the phone (which is usually electrically non-conductive) and packaging constraints necessitate placement of the phone’s battery and power electronics in close proximity, with limited opportunities to dissipate heat generated in the phone, or shield the phone from heat generated by the charger. It has been well-documented that batteries age more quickly when stored at elevated temperatures and that exposure to higher temperatures can thus significantly influence the state-of-health (SoH) of batteries over their useful lifetime.
The rule of thumb (or more technically the Arrhenuis equation) is that for most chemical reactions, the reaction rate doubles with each 10 °C rise in temperature. In a battery, the reactions which can occur include the accelerated growth rate of passivating films (a thin inert coating making the surface underneath unreactive) on the cell’s electrodes. This occurs by way of cell redox reactions, which irreversibly increase the internal resistance of the cell, ultimately resulting in performance degradation and failure. A lithium ion battery dwelling above 30 °C is typically considered to be at elevated temperature exposing the battery to risk of a shortened useful life.
Guidelines issued by battery manufacturers also specify that the upper operational temperature range of their products should not surpass the 50−60 °C range to avoid gas generation and catastrophic failure.
These facts led WMG researchers to carry out experiments comparing the temperature rises in normal battery charging by wire with inductive charging. However the WMG were even more interested in inductive charging when the consumer misaligns the phone on the charging base. To compensate for poor alignment of the phone and the charger, inductive charging systems typically increase the transmitter power and/or adjust their operating frequency, which incurs further efficiency losses and increases heat generation.
This misalignment can be a very common occurrence as the actual position of the receiving antenna in the phone is not always intuitive or obvious to the consumer using the phone. The WMG research team therefore also tested phone charging with deliberate misalignment of transmitter and receiver coils.
All three charging methods (wire, aligned inductive and misaligned inductive) were tested with simultaneous charging and thermal imaging over time to generate temperature maps to help quantify the heating effects. The results of those experiments have been published in the journal ACS Energy Letters in an article entitled “Temperature Considerations for Charging Li-Ion Batteries: Inductive versus Mains Charging Modes for Portable Electronic Devices.”
The graphics with this press release illustrates three modes of charging, based on (a) AC mains charging (cable charging) and inductive charging when coils are (b) aligned and (c) misaligned. Panels i and ii show a realistic view of the charging modes with a snapshot of the thermal maps of the phone after 50 min of charging. Regardless of the mode of charging, the right edge of the phone showed a higher rate of increase in temperature than other areas of the phone and remained higher throughout the charging process. A CT scan of the phone showed that this hotspot is where the motherboard is located In the case of the phone charged with conventional mains power, the maximum average temperature reached within 3 hours of charging did not exceed 27 °C.
In contrast this for the phone charged by aligned inductive charging, the temperature peaked at 30.5 °C but gradually reduced for the latter half of the charging period. This is similar to the maximum average temperature observed during misaligned inductive charging.
In the case of misaligned inductive charging, the peak temperature was of similar magnitude (30.5 °C) but this temperature was reached sooner and persisted for much longer at this level (125 minutes versus 55 minutes for properly aligned charging).
Also noteworthy was the fact that the maximum input power to the charging base was greater in the test where the phone was misaligned (11W) than the well-aligned phone (9.5 W). This is due to the charging system increasing the transmitter power under misalignment in order to maintain target input power to the device. The maximum average temperature of the charging base while charging under misalignment reached 35.3 °C, two degrees higher than the temperature detected when the phone was aligned, which achieved 33 °C. This is symptomatic of deterioration in system efficiency, with additional heat generation attributable to power electronics losses and eddy currents.
The researchers do note that future approaches to inductive charging design can diminish these transfer losses, and thus reduce heating, by using ultrathin coils, higher frequencies, and optimized drive electronics to provide chargers and receivers that are compact and more efficient and can be integrated into mobile devices or batteries with minimal change.
In conclusion, the research team found that inductive charging, whilst convenient, will likely lead to a reduction in the life of the mobile phone battery. For many users, this degradation may be an acceptable price for the convenience of charging, but for those wishing to eke out the longest life from their phone, cable charging is still recommended.
26 JUNE 2019
NOTES FOR EDITORS
While one specific model of mobile phone was used to conduct the tests the issues raised obviously apply to all phones or portable devices now or in the future that seek to use inductive charging.
High-res image available at: https://warwick.ac.uk/services/communications/medialibrary/images/june2019/iphone_charging_mode_2.jpg
Credit: WMG, University of Warwick
Paper available to view at: https://pubs.acs.org/doi/10.1021/acsenergylett.9b00663
List of Authors (all WMG) include:
Melanie. J. Loveridge
Chaou C. Tan
Faduma M. Maddar
The future of daily urban commuting could be small, lightweight Electric L-category Vehicles (ELVs). A cost effective, energy efficient and comfortable alternative to traditional cars in cities, is at the heart of the €6.92m RESOLVE project, which included WMG at the University of Warwick.
The European project – named ‘Range of Electric Solutions for L-category Vehicles’ – designed and developed two stylish tilting four-wheeler prototype ELVs with leading European manufacturers Piaggio and KTM. These demonstrators were unveiled, and presented to representatives from the European Commission, at an event in Brussels in April 2018.
WMG was one of fourteen partners in the project, which included leading names from industry and research such as Piaggio, KTM, Bosch, Ricardo, the Austrian Institute of Technology, and the University of Florence.
Electric vehicle charging infrastructure on UK roads is to be advanced, thanks to a new £5.6 million project – funded by Innovate UK – to develop Vehicle-2-Grid (V2G) technologies, involving WMG at the University of Warwick.
For three years from April 2018, the EV-elocity consortium will conduct a project to demonstrate and develop V2G technology across a variety of UK locations, including airports and business parks – with the aim of proving its viability and worth to business and the wider public.
Researchers at WMG, led by vehicle electrification and energy storage expert Dr James Marco, will build a techno-economic model of how V2G will be viable within the UK. A key innovation will be the inclusion of new models of battery degradation within the analysis that will underpin new methods to optimise the vehicle’s battery system.
Dr Marco’s team will also analyse real-world usage data from a range of different electric fleet vehicles as they are used within a V2G context.
The project will break new ground in helping consumers, businesses and infrastructure providers to financially benefit from adapting their charging behaviour and vehicle use.
In doing so, the project will help to further accelerate and incentivise the transition from traditional fuel sources to electric vehicles.