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CT scans of batteries

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Re: CT scans of batteries

#61

Post by ggm »

rbanffy wrote: post #60
ggm wrote: post #54

Earlier quoted context omitted.

if I remember my basic chemistry, batteries don't deliver voltages at the level of 10/20/100v directly often, its more commonly 1/2v or 0.5v class voltages. You have to have a much more 'aggressive' chemical reaction to deliver higher voltages. And, the same with current: a single surface between two reacting things delivers less current. Its a function of surface area. Same with capacitance: you sometimes need 'more…

> Inside a lead acid battery its multiple surfaces, sub-cells. IIRC, “battery” used to be the technical term for “a bunch of connected power cells”.

Yes. A battery of guns isn't usually just one. It's a set word. The singleton would be cell.

Re: CT scans of batteries

#62

Post by habi »

richk449 wrote: post #58
dsalzman wrote: post #6

The company behind these scans is https://www.lumafield.com/ - a really cool way to do marketing for your product. Love it!

Anyone know what energy the x-ray source is in their system? Seems really well designed, but if it doesn't have energy energy to penetrate the devices we need to scan, none of that will matter.

They don't mention anything on their website, but I guess - from looking at their machine - that they use an x-ray source which goes to the range of 150kV, since they also show larger items with more metal volume being scanned.

*source: I work with two of the machines here: https://www.bruker.com/en/products-and-solutions/microscopes... (and one more from Bruker which is so old that they don't show it on their website anymore).

Re: CT scans of batteries

#63

Post by sudhirj »

another_story wrote: post #43

Can CT scans be used to create 3D models with internal components?

Might have to apply a layer of analysis over it. From what I understand the scan is a 3D maps of point densities, so it may or may not obvious what the separate components are.

If a device was made up of components that all had very different densities, maybe one could analyze the points and determine components and do a “explode” animation.

Re: CT scans of batteries

#64

Post by HPsquared »

derkades wrote: post #42
scrumper wrote: post #38

Very interesting! Confused by the text about the alkaline scan (the first one). The +ve side is called the anode isn’t it, not the cathode? And electrons originate at the cathode not the anode. Or is the usual terminology inverted because it’s a battery or this particular type of battery? I don’t know much about batteries; chemistry never a strong suit.

As I understand it, the cathode is where electrons "leave", the anode is where they "enter". In case of a battery, electrons leave the minus side. But for a device being powered, electrons enter the minus side.

I always remember it by thinking about a cathode ray tube - on that, the flying electrons are called "cathode rays", i.e. the cathode shoots out the electrons that came in from the external connection. The power supply pushes electrons into the "cathode" terminal on the device. That is, "positive current" flows out of the cathode (in the opposite direction to the electrons).

Re: CT scans of batteries

#65

Post by Bayart »

anon946 wrote: post #44
vitruvius wrote: post #2

The LG lithium ion cell that's second on this page is the one inside the Tesla Model Y battery pack.

That's interesting and somewhat surprising. I'm not knowledgeable about battery design by any means, but I would have thought that there would be a better way to make a battery pack for a car than connecting thousands of small batteries together.

Using standard form factors and manufacturing techniques made it much easier for Tesla to get batteries off the ground through their partnership with Panasonic. The extra space left by the gaps between cells also has the advantage of being ideal for cooling (battery performance and safety is correlated to temperature).

Re: CT scans of batteries

#66

Post by HPsquared »

caycep wrote: post #49

How are they getting color? My impression is CT scan is mostly measuring density and x-ray absorption. Are they doing false color based on some sort of data (vs photoshop?)

I think in this case it's just the density (absorption) but on some machines it's possible to use different energy levels of x-rays (so-called dual energy CT) to see variations in materials/chemistry, that works in a similar way to colour in the visual spectrum (different materials absorb different energy levels of light differently).

Re: CT scans of batteries

#67

Post by pjc50 »

anon946 wrote: post #44
vitruvius wrote: post #2

The LG lithium ion cell that's second on this page is the one inside the Tesla Model Y battery pack.

That's interesting and somewhat surprising. I'm not knowledgeable about battery design by any means, but I would have thought that there would be a better way to make a battery pack for a car than connecting thousands of small batteries together.

Separating the cells allows makes it easier to cool them. It also provides more inert metal between them in case of fire.

A certain amount of stacking is necessary to get up to a decent voltage, as others have pointed out. But even "100 brick-sized cells" would be a more dangerous prospect than "thousands of 18650 cells".

Re: CT scans of batteries

#68

Post by michaelt »

anon946 wrote: post #44
vitruvius wrote: post #2

The LG lithium ion cell that's second on this page is the one inside the Tesla Model Y battery pack.

That's interesting and somewhat surprising. I'm not knowledgeable about battery design by any means, but I would have thought that there would be a better way to make a battery pack for a car than connecting thousands of small batteries together.

The Nissan Leaf uses larger cells [1], each roughly the size of a ream of printer paper. So there are real car designers who agree larger batteries are worth considering.

Of course, the Leaf makes a bunch of other decisions that are different to Tesla - lower price point, smaller battery/reduced range, air-cooling batteries instead of water-cooling, a (now abandoned) battery lease scheme, and suchlike.

[1] https://www.google.com/search?q=nissan+leaf+cell&tbm=isch

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