What to do if the functional unit is not connected to the toppest process module

Question

Hi,

I am currently modeling a product system. It contains the production of battery modules, their combination to an EV battery, the reuse as power wall and in the end the disassembly and the recycling of the modules. The toppest process is accordingly "Battery_Module_Recycling" which has as output the reference flow "Battery_Module_Disposed". This becomes the products system's functional unit. However, I would like the functional unit to be the produced modules (or their associated capacity). I have not found a way to change the system's reference flow to the modules produced without deleting the entire use phase. Is there a way to do so?

https://ask.openlca.org/?qa=blob&qa_blobid=1549593149607137734

This is the toppest flow. It follows the opposite direction approach.

https://ask.openlca.org/?qa=blob&qa_blobid=7016518825137506673

I would like this Battery_Module flow the product system's reference flow.

 

I would highly appreciate an answer. Thank you in advance!

Answer 1

Hi, there are two solutions: 1, you can create a separate product system for each phase and let each of these feed into a "life cycle" product system, which provides the functional unit; 2, the most natural way would be (I think) to set the battery in use as functional unit, and model the waste battery that is output of the use phase as waste. Then the use phase is at the top, so to say.

Success! Andreas

Comments

Hi Andres,

Thank you very much for the quick answer. i really appreciate!
However , I encountered some difficulties.
I tried defining the Battery_Module_Disposed as waste flow. If I understood correctly what you explained in solution 2, the flow one level "lower" should become the new reference flow, accordingly Battery_Module_To_Dispose. When performing the analysis, Battery_Module_Disposed (being a waste flow) is still is the reference flow and I can't choose anything else.
Maybe I made a mistake or didn't understand your explanation correctly?
Concerning Solution 1, I don't really understand how this "life cycle product system" would look like. Do you have an example or could you explain again?

Cheers,
Roman