All 2 entries tagged Ev
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July 01, 2016
Welcome back to the ABACUS Blog for the monthly update. In the month of July the topic of Safety for Lithium-ion batteries will be discussed.
In the forward and reverse logistics chain of a Lithium-ion battery, storing and handling the battery safely is of vital importance. Some of the pre-failure processes that needs to be managed and minimised through proper storage and handling in the supply chain are:
- Cells being operated or stored in extreme temperatures (high temperature leading to modification of surface films on the electrodes, low temperature leading to the breakdown of adhesives causing anode to pull away from current collector)
- Cell damage and defects that can cause internal short circuits leading to localised heating spots
- High charge/discharge current during state-of-charge adjustment (Wheat=I2 * Zint)
- Improper connections causing high resistance
- Mechanical damage (Crash, Vibration, Mishandling)
In terms of safety for the people involved in the reverse logistics supply chain there are two scenarios to consider namely safety to prevent an event and safety to handle an event that occurred.
For safety to prevent an event there are three things that I want to highlight:
1. In the UK the Heatlh and Safety Executive (HSE) under the Health and Safety in the workplace act of 1974 created a guide for handling batteries safely. Also, for High Voltage (HV) batteries with DC voltages greater than 50V it is important to be certified to work with HV equipment and HV training is essential for making a traction Lithium-ion battery safe.
2. Safe packaging requirements for transportation is covered under the ADR regulations in the EU but no proper international standards or guides exist for proper storage for Lithium-ion batteries that I am aware of.
3. Appropriate State-of-Charge (SoC) of the cell when put into storage needs to be considered. Some of the factors to consider when adjusting a cell's state-of-charge for storage are the following:
- How long can the cells be stored for? (shelf life) - the cell's self-discharge rate and storage temperature needs to be considered carefully to ensure cell do not reach a SoC level that is two low and can damage the cell. Higher temperatures will cause the self-discharge rate to increase.
- Transport requirements: For example from 1 April 2016 all Lithium-ion battery packs shipped by air under IATA package instruction 965 must be at no more than 30% state of charge due to the possibility of cells or batteries in a higher state of charge could reach more violently if damaged or abused.
For safety to handle an event the following is worth noting:
- There are first responder guides available for various vehicle brands at http://www.evsafetytraining.+org/resources.aspx. The issues with the guides are that the responders are guided to cut the 12V line and from a testing point of view and ADR transport regulation point of view this makes verifying the status of the battery more difficult.
- Procedures to make batteries safe after venting or fire such as to put it in a salt water bath to discharge the battery because damaged packs need to be rendered safe before transportation. This destructive approach has major limitations as it does not guarantee the pack is safe and produces toxic gas and corrosive lithium chloride with undesirable environmental consequences.
Thus it is important to carefully consider all the safety aspects when working with lithium batteries and to have a clearly defined mitigation plan to prevent incidents.
Until next time!
November 11, 2015
Welcome to the Abacus blog and welcome to November 2015. This is the first blog entry to introduce the topics that will be discussed over the next coming months. The following months will be dedicated to discuss the eight research themes that the project identified by considering the reverse logistics value chain for an Electric Vehicle (EV) battery and highlighting potential barriers to extending the in-use life of the EV battery.
The motivation behind EV battery in-use life extension stems from the need to adopt a move from the traditional take-make-dispose business model to a circular model due to legislation such as the Battery directive and the End-of-Life (EoL) vehicle directive. The Battery directive (Directive 2006/66/EC) prohibits the disposal of automotive batteries and industrial batteries (which include EV battery packs) by means of landfill or incineration. The EoL vehicle directive (Directive 2000/53/EC) also known as the End-of-life vehicles (ELV) directive specifies measures which aim to prevent waste from vehicles at the reuse, recycling and other forms of recovery stages of EoL vehicles and their components to reduce the disposal of waste. The ELV directive measures have two components - it set out quantified targets for reuse, recycling and recovery and also pushes producers to manufacture new vehicles without hazardous substances that prohibits reuse, recycling and recovery of waste vehicles. More information about the directives can be found at http://eur-lex.europa.eu/legal-content/en/ALL/?uri=CELEX:32006L0066 and http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex:32000L0053 and will also be discussed further in the Ownership and Liability blog entry.
The value chain that includes the reverse logistics for an EV involves many stakeholders including the battery pack manufacturer, EV manufacturer, EV dealer, customer, remanufacturer, Authorised Treatment Facility (ATF), Approved battery Exporter (ABE), and the Approved Battery Treatment Operator (ABTO). The research themes identified in the project are:
- Best practice benchmarking - What are the other companies doing?
- Transport and Storage
- Ownership and Liability
So in the upcoming months each of these topics and the opportunities and barriers for the relevant stakeholders will be discussed in the blog posts. We hope you find it informative and useful!
Until next time…
The ABACUS team.