Research paper: "Surface Cooling Causes Accelerated Degradation Compared to Tab Cooling for Lithium-Ion Pouch Cells" Ian A. Hunt, Yan Zhao, Yatish Patel and G. J. Offer jes.ecsdl.org/content/163/9/A1846
@@vtorsi610 10 minutes is 6C, like climbing a mountain pass. Racing pack builders plan for this average, with peaks even higher. Since heating is a function of current squared, you need all the cooling advantage you can get in racing applications. The difference between 3C and 6C is four times the heating.
We have a product ready ith tab cooling and can maintain the lead acid batteries at optimal temperatures at all times irrespective of the ambient temperature
It's common sense once you know the construction of the cell. There are other videos where people take cells apart. Thank you for the research, and sharing.
Hej, grate video. However I wonder how different cell types affect this? What cell form factor did you use? A cylindrical cell cooled at surface like a 2170 have maximum about 21mm between cooler plate and extremity of cell. A pouch cell that is cooled only at tabs can have >100mm. Fully agree that the negative aging effect very related to the difference in temperature inside the cell. However the conclusion that tab cooling is better is to generic and cell design, etc needs to be included. I think I will have to read the report as it probably have this info. Grate video, keep up the good work!
Agreed. The narration hints at the use of prismatic cells for the test, then explains the conclusion made based on the results in a hypothetical EV example. But, I'm not sure many EVs use prismatic cells. For example, Tesla favor cylindrical cells.
First the prismatic cell needs constant presure on the walls. Be serios, the tabs are small, the thermal conductivity is far small across a few mm, than the total thermal conductivity ofered by only one side.... this presentation is JUNK!
Lucid (the battery maker for Formula E) uses cylindrical cells like Tesla and cools at one end of the cell. They state in their video that the thermal conductivity is different for the 2 types of cooling, and that the equivalent of the tab cooling (end cooling) is much more effective. Based on the direction of the layers of copper (very conductive), that's probably true.
Great educational video from 2016/2017. In 2020 (Tesla's battery day) Tesla is going to change the cooling system with the new bigger battery 4680 to a tab cooling (or bottom cooling) like the Jaguar I-pace. Maybe the Berlin's made Model Y will be the first to implement this cooling.
How do I get more details on this experiment so I can repeat it? Because, you know, science. What type of cells were used? The narration hints that the cells were prismatic. What about cylindrical cells? When the tab cooled cells were tested, how were the cells supported? Were the cells surrounded by some supportive, perhaps insulative structure? Otherwise, if the tab cooled cells were captured only by their tabs, then the cells might have been considered tab cooled as well as wall cooled by ambient air. Very effective cooling, but not a rugged way to mount a prismatic cell for any practical use. At least when cooling by cell wall, the cell is captured by the heat sink, which lends itself to more practical application.
What about surface cooling in a direction parallel to the tabs? I'm curious what the results would have been if you placed the surface coolers on the other sides of the cell
Does this apply across cell types (cylindrical; pouch; prismatic), and if so, are the effects quantitatively similar, or different (and if the latter, by how much)? How does this translate to C rate, particularly where discharge is concerned? Is there a threshold under which these considerations are marginal?
That's why we have used tab cooling (top and bottom cold plates) for our 18650 cell based custom ESS (battery subsystems) for the past 5 years in all of our custom powertrain designs.
@@jaybabu3220 Because under NORMAL USE, nobody will ever discharge the entire battery pack in just 10 MINUTES. A 10 Minute Discharge test is a very stupid test. Extra cooling may be needed in Ludicrous Mode ...
I'm with ya. Working on a project involving computational transport phenomena to investigate how thermal management of Tesla's new tabless cell design may be advantageous to that of the current 2170. This new design literally changes everything.
Cooling with a solvent? Probably not a good idea. At least with a non conductive fluid, both the tabs and the cell sides could be simultaneously cooled though
Surface Cooling - because Surface Cooling "good enough" under NORMAL USE. Also, Tesla does NOT use Pouch Cells and NOBODY discharges their battery pack in 10 minutes. A "10 minutes discharge test" is a very stupid test. Have you ever consumed an entire tank of gasoline in just 10 minutes - NO, you have not, not ever, because your engine would get way too hot = a very stupid test ...
1. The given cell do not have the tabs on opposite side, so I doubt about the uniformity of cell you are getting. 2. If you are testing for EVs battery degradations the ambient temperatures matters a lot. Have you tested it for the climatic condition for more than 35 or 40 degC and below 5 degC. I guess the results will be different in those cases, Also what is the average temperature you are getting in this cases. 3. For a prismatic cell results seems promising but for Kokam SLPB11543140H5 model with width only 11.7mm and providing both surfaces with liquid cooling i dont think the temperature difference could be more than say max to 1 degC or 0.5 degC. Have you checked the difference what is it?
Exactly! Actually, the cars usually have a big battery to provide the range. This means that very less current flows through any one cell at a time. The research says that at lower discharge rates, it does not matter much as to which way you cool. Further, Tab cooling is inefficient and you take this energy out of the battery anyway. This research makes more sense in power applications like power tools or Outdoor Power Equipments (OPE) which currently run on small engines. But they cannot have a heavy liquid cooling setup anyway. One area where this can be useful is the electric race cars but there the aim is not to run for years.
