Why Lead Acid Batteries Have 12V, But Not Lithium Batteries?

[24v-lithium-battery]

Why Lead-Acid Battery Voltages are Neat Whole Numbers while Lithium-ion Battery Voltages Have Decimal Points.

You may find it odd that lead-acid battery voltages come in neat whole numbers like 12V, 24V, 36V, while lithium-ion battery voltages are 12.8V, 25.6V, 38.4V - it almost seems designed to annoy obsessive compulsive people. Why can't they just make the voltages integers as well?

The answer lies in the inherent material properties of the different battery chemistries. First, batteries are constructed by connecting individual battery cells in series and/or parallel, so the overall battery voltage must be an integer multiple of the single cell voltage.

A lead-acid battery cell has a nominal voltage of 2.0V. So connecting 6 cells in series results in a 6 * 2.0V = 12V battery, which matches the most common lead-acid battery specification found on the market.

Meanwhile, a lithium-ion battery cell has a nominal voltage of 3.2V. To match the 12V lead-acid specification, it would require connecting 4 cells in series, resulting in 4 * 3.2V = 12.8V - just enough to replace a 12V lead-acid battery.

But why can't the lithium-ion cell voltage also be specified as a neat 2.0V like lead-acid? This gets back to the fundamental principle of what voltage actually represents.

Voltage is the electric potential difference between the positive and negative terminals of a battery. Different metal and conductor materials inherently produce different potential differences based on their material properties alone, independent of quantity or geometry.

For a given lead-acid chemistry, the cell voltage will always be around 2.0V. And for a given lithium-ion chemistry using lithium and carbon electrodes, the cell voltage will always be around 3.2V.

So in summary, the reason lithium-ion batteries specify voltages with decimal points is solely due to the intrinsic material properties that determine the potential difference of its cell chemistry. This cannot be separated from the basic workings and construction of the battery.

 

[SalisburySam]

Glad that’s cleared up, whew!

Kudos though for making your first post an informative one.

 

[cornbinder89]

The reason lithium-ion batteries specify voltages is solely due to the intrinsic material properties that determine the potential difference of its cell chemistry. This cannot be separated from the basic workings and construction of the battery.

There, that is all you needed to post.

 

[Chad E. Mo]

This looks like chatbot spam to me... note (but do not click) the link in the body of the message.

This is a rapidly expanding problem on other fora I participate in.

I have reported this as spam to the moderation team.

 

[cornbinder89]

This looks like chatbot spam to me... note (but do not click) the link in the body of the message.

This is a rapidly expanding problem on other fora I participate in.

I have reported this as spam to the moderation team.

Me thinks, you just may be correct :<)

 

[24v-lithium-battery]

This looks like chatbot spam to me... note (but do not click) the link in the body of the message.

This is a rapidly expanding problem on other fora I participate in.

I have reported this as spam to the moderation team.

nope....just a knowledge about lithium battery.

 

[24v-lithium-battery]

Glad that’s cleared up, whew!

Kudos though for making your first post an informative one.

thx

 

[Bombastinator2]

Why Lead-Acid Battery Voltages are Neat Whole Numbers while Lithium-ion Battery Voltages Have Decimal Points.
View attachment 3031
You may find it odd that lead-acid battery voltages come in neat whole numbers like 12V, 24V, 36V, while lithium-ion battery voltages are 12.8V, 25.6V, 38.4V - it almost seems designed to annoy obsessive compulsive people. Why can't they just make the voltages integers as well?

The answer lies in the inherent material properties of the different battery chemistries. First, batteries are constructed by connecting individual battery cells in series and/or parallel, so the overall battery voltage must be an integer multiple of the single cell voltage.

A lead-acid battery cell has a nominal voltage of 2.0V. So connecting 6 cells in series results in a 6 * 2.0V = 12V battery, which matches the most common lead-acid battery specification found on the market.

Meanwhile, a lithium-ion battery cell has a nominal voltage of 3.2V. To match the 12V lead-acid specification, it would require connecting 4 cells in series, resulting in 4 * 3.2V = 12.8V - just enough to replace a 12V lead-acid battery.

But why can't the lithium-ion cell voltage also be specified as a neat 2.0V like lead-acid? This gets back to the fundamental principle of what voltage actually represents.

Voltage is the electric potential difference between the positive and negative terminals of a battery. Different metal and conductor materials inherently produce different potential differences based on their material properties alone, independent of quantity or geometry.

For a given lead-acid chemistry, the cell voltage will always be around 2.0V. And for a given lithium-ion chemistry using lithium and carbon electrodes, the cell voltage will always be around 3.2V.

So in summary, the reason lithium-ion batteries specify voltages with decimal points is solely due to the intrinsic material properties that determine the potential difference of its cell chemistry. This cannot be separated from the basic workings and construction of the battery.

Those numbers are a bit fuzzy anyway. Batteries are sorta like balloons. The “nominal” voltage of, say an 18650, is 3.7v, but what that really means is it will hold up to 4.2 and report itself as empty around 2.5.