old-second-life-stuff.tex

\iffalse % TODO, do we need this?
\section{Second Life Solutions} \label{sec:secondlifesolutions}
% TODO https://github.com/dalathegreat/Battery-Emulator
% TODO companies?

\section{Moving from battery modules to whole vehicles}
% TODO rewrite this to get away from second life applications
When discussing second life applications today, the assumed approach is usually to strip the battery out of a vehicle and using it for stationary energy storage.
As of today there are already over 100 different models of electric vehicles from over 30 different manufacturers. Each model usually comes with a proprietary battery management system. % TODO: cite https://de.wikipedia.org/wiki/Liste_von_Elektroautos_in_Serienproduktion and correct numbers
Traditional second life approaches assumed to talk directly to the battery management system (BMS) of battery taken out of a full vehicle.
When implementing a second life scenario, this requires interfaces to different bus systems used by BMSs as well as implementing thousands of different BMS communication schemes.
Often the BMS of vehicles relies on other vehicle components which have to be emulated in a second life scenario, increasing implementation complexity even further.
For companies developing second life solutions, this means either narrowing down to a small number of vehicle manufacturers and models or having an overwhelming number of BMS interfaces to implement.
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The second life approach presented in this paper is based on the following assumptions:
\begin{enumerate} % TODO find citations for those numbers
    \item Battery electric vehicles are used in their first life until the battery reaches between 70\% and 80\% state of health (SOH).
    \item Todays batteries can be charged and discharged around 2000 to 3000 times before reaching this 70\% SOH
    \item The average final odometer of a vehicle before scrapping is 400000km
\end{enumerate}
Combining these facts together with a typical electric range of a mid sized electric vehicle gives a total battery lifetime of 700000 up to over 1 Million km.
This means vehicles are usually sent to the scrapyard way before the first battery would exceed its first life.
While exemptions of these assumptions surely exist, e.g. for vehicles for vehicles where the owners take care of protecting them from corrosion, there will still be a large number of vehicles finishing its first life because of non battery reasons long before the battery has to be replaced. \\
Since the facts described above suggest a large number of full vehicles (rather than only batteries) being available for second life use, this paper discusses second life approaches using the full vehicle rather than only the battery module.
The main advantage of using the full vehicle is the availability of the charge port.
Since charging an electric vehicle is standardized across manufacturers and models, this approach removes the need of implementing specific code for each vehicle make.
\fi