Howard has joined AAPS CDT after graduating from Imperial College London where he studied Mechanical Engineering. Having grown up on a farm, Howard spent much of is early life tinkering with engines and machines giving him an affinity for solid mechanics. During this time Howard demonstrated a natural ability through his knowledge of ICEs and transmissions, and found a new affinity for electrical systems. This led to mechatronics as a desired field of study and under Dr. Costall (who joined IAAPS in 2020) in his final year, he undertook research into the viability of the electrification of agricultural machinery. Overcoming a lack of knowledge and guidance available to him in this area he produced a bottom-up analysis of tractors including 12 independently recorded duty cycles with results intended to be published imminently.
Howard's PhD will investigate the influence that current ripple has on a Lithium-ion battery cell when it is applied on top of the DC current used to charge/discharge the cell.
Aim:
To understand the influence DC ripple current has on lithium-ion cells in automotive applications, by testing and examining the results of cells applied with various types and frequencies of ripple
Seek to find an explanation of these results with respect to electrochemical theory
This information should aid decisions made in the design of electric vehicles specifically associated with the e-machine and accompanying inverter/power electronics
Objectives:
Conduct a thorough literature review to analyse:
Current and past works and any relevant findings
Any gaps or oversights in these works
Any areas of work that need confirmation
Use electrochemical modelling to select the most relevant parameters associated with DC ripple in Li-ion cells, using this modelling to design an experiment including optimum yet achievable ranges of said parameters
Ripple magnitude, frequency, waveform etc.
Cell chemistry, size, shape etc.
This may include some very preliminary testing to validate any assumptions made about equipment or expected results
Conduct the designed experiment varying the relevant variables whilst recording performance metrics decided in modelling stage
E.g. Capacity fade, power fade, EIS
Beamline experiment for XRD and XAFS for in situ monitoring of the battery with/without ripple to gain insight otherwise unavailable
Process results to see if any additional experimentation is needed
This will likely include a post-mortem analysis of cells by dissection and inspection
Seek to find an explanation for these results through electrochemical theory to truly understand the phenomena observed
Theoretical understanding should explain the empirical data
This will itself be a contribution to knowledge
Potential to exploit these results in the design of Battery Management System (BMS) and even validate these design implications
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