Does a fully charged Taycan weigh the same as one that's nearly depleted?

[SWORDER]

Got into an discussion about whether or not Taycan is "weighed down" after being fully charged, similar to how an ICE vehicle becomes heavier after filling the tank.

I'm not a science guy but vaguely remember from high school that electrons have no mass. So it seems, in theory at least, that the fully charged vehicle should weigh the same as the depleted one (all other factors being equal).

Before pressing send on this post, I actually Googled "do electrons have mass?" Some people say that they have none. Others indicated that electrons actually do have a mass of 9.1093837015 × 10 −31 kg. If the latter is indeed true, would that mean that the charged vehicle would indeed be heavier, but by so little that conventional scales would be unable to detect it?

What exactly is happening when we charge our vehicles? Are fresh new electrons being injected into the battery? Or is it just using existing electrons and changing their charge, or maybe moving them from the "positive" side to the "negative" side (or vice versa)? Do the electrons just burn off when consumed as the car is driven, kind of like gasoline does when a ICE gar is driven, or do they still hangout in the battery but just in a just different state?

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[wurzitup]

No change in weight. Electrons effectively have no mass. And if you can detect their mass, you correspondingly can't know they are in the battery.
Coming from someone with a degree in radiation science and radiation physics.

 

[daveo4EV]

Got into an discussion about whether or not Taycan is "weighed down" after being fully charged, similar to how an ICE vehicle becomes heavier after filling the tank.

I'm not a science guy but vaguely remember from high school that electrons have no mass. So it seems, in theory at least, that the fully charged vehicle should weigh the same as the depleted one (all other factors being equal).

Before pressing send on this post, I actually Googled "do electrons have mass?" Some people say that they have none. Others indicated that electrons actually do have a mass of 9.1093837015 × 10 −31 kg. If the latter is indeed true, would that mean that the charged vehicle would indeed be heavier, but by so little that conventional scales would be unable to detect it?

What exactly is happening when we charge our vehicles? Are fresh new electrons being injected into the battery? Or is it just using existing electrons and changing their charge, or maybe moving them from the "positive" side to the "negative" side (or vice versa)? Do the electrons just burn off when consumed as the car is driven, kind of like gasoline does when a ICE gar is driven, or do they still hangout in the battery but just in a just different state?

there is no change in mass as a result of the trivial amounts of power being added the battery - and in the grand scheme of physics vs. mass - 93 kWh is trivial.

 

[daveo4EV]

https://physics.stackexchange.com/q...s-of-a-battery-change-when-charged-discharged

 

[Klepper]

From that link above:

"Electrons are not lost when a battery is discharged. If a battery is losing electric energy, it doesn't mean that it's losing the electric charge! They're just moved from one electrode closer to the other and it's just the motion through the wire stretched between the electrodes (and the electric field inside the wires) that powers the electric devices. But the whole battery is always electrically neutral; because it contains a fixed number of protons, it must contain a fixed (the same) number of electrons, too."

 

[JimBob]

With respect to your last question,

https://electronics.stackexchange.c...trons-actually-flow-when-a-voltage-is-applied

In particular start at the line "Thinking about current in terms of electrons moving around is the start down a path to a poor mental model of how electricity works. Here are just a few things wrong with it:"

 

[Vercingetorix]

From that link above:

"Electrons are not lost when a battery is discharged. If a battery is losing electric energy, it doesn't mean that it's losing the electric charge! They're just moved from one electrode closer to the other and it's just the motion through the wire stretched between the electrodes (and the electric field inside the wires) that powers the electric devices. But the whole battery is always electrically neutral; because it contains a fixed number of protons, it must contain a fixed (the same) number of electrons, too."

So then why the need to recharge? Something is lost due to heat.

 

[Klepper]

So then why the need to recharge?

To move them back to the other electrode again.

 

[Vercingetorix]

To move them back to the other electrode again.

https://www.physicsforums.com/threads/are-charged-batteries-heavier.940974/

 

[Klepper]

Electrons are not being added to the battery. They are just moving around.

From: https://letstalkscience.ca/educational-resources/stem-in-context/how-does-a-lithium-ion-battery-work

 

[Vercingetorix]

Electrons are not being added to the battery. They are just moving around.

From: https://letstalkscience.ca/educational-resources/stem-in-context/how-does-a-lithium-ion-battery-work

But do the mass of the electrons remain the same? The question is not If electrons are moving around the question is if the mass increases.

 

[285kph]

With respect to your last question,

https://electronics.stackexchange.c...trons-actually-flow-when-a-voltage-is-applied

In particular start at the line "Thinking about current in terms of electrons moving around is the start down a path to a poor mental model of how electricity works. Here are just a few things wrong with it:"

Well, electric current is quite literally the net motion of charge carriers through a circuit per unit of time, and for most power circuits those charge carriers are electrons.

But indeed, no electrons are lost or added when discharging or charging a battery - it is just the chemical configuration of charges within the battery that is changed.

Regarding the original question, charging the Taycan battery from 0 to 100% should change the weight by a few micrograms, i.e., the mass corresponding to the stored energy.

 

[285kph]

Before pressing send on this post, I actually Googled "do electrons have mass?" Some people say that they have none. Others indicated that electrons actually do have a mass of 9.1093837015 × 10 −31 kg.

I'm not sure if I this is funny or deeply disturbing. Whether electrons have mass or not is not a matter of debate or opinion, but a simple scientific fact that can be verified in any number of experimental approaches. The correct answer is that electrons have a rest mass as indicated above, within a small uncertainty. "Some people" have no clue and should not be talking.

 

[epirali]

Well technically the "energy" stored that will be used in the electrons moving around DOES have mass. But if you use E=MC^2 and work backwards the mass=E/(C^2). So technically yes it weights more, but I am not sure if we have precise enough instruments to measure the increase in mass...

 

[F16HTON]

I noticed my Taycan was heavier after a full charge, however maybe that was due to the lunch I had eaten?

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