Understanding How Batteries Store & Release Energy

In summary, the conversation discusses the concept of batteries and how they store energy. It is explained that a battery can be thought of as two separate plates, one accumulating positive charges and the other negative, separated by an electrolyte. When an external circuit is formed between the battery terminals, the potential energy is converted to electrical energy as electrons flow through the wires. It is also noted that a battery is different from a capacitor, which stores energy in an electric field rather than through a chemical reaction. The conversation also delves into the differences between DC and AC current and how a capacitor behaves in each.
  • #1
u0362565
52
0
Hi all,

For some reason I'm really struggling to understand how batteries store energy and how this relates to electric potential.

Can I just think of a battery as two separate plates one accumulating positive charges the other negative. The positive and negative charges are attracted but they are kept apart by the electrolyte? The only way for equilibration to occur or the electric potential to be converted to electrical energy is when the external circuit is formed between the battery terminals. At that point, electrons have an easy route to the positive terminal and the potential energy is lost on whatever load is in the external circuit? Is that about right? A bit like a hydroelectric dam where water is pumped up hill creating potential energy this is like the separation of unlike charges in the cell. When the dam is opened the waters potential energy becomes kinetic. In the batteries case the terminals are connected with wire and the electons flow losing their potential but the process is this in a constant loop until the battery drains.
 
Engineering news on Phys.org
  • #2
Isn't it chemical energy that the battery initially stores? the positive and the negative plates/terminal are being separated by some chemical paste (lead) which is electrolytic. This chemical allows electrons to pass. The potential energy that you might saying must be the energy possessed by the electrons when they are not being used.
 
  • #3
A battery is simply a component in a circuit that converts chemical energy into electrical energy by means of electrons. Under ideal situations, electrons can travel from one chemical to another. When the electrons move, they make an electrical charge that can powers things. In a battery, there are chemicals that can make the electrons create electric charge. However, there is a wall that forces the electrons (with the charges, positive and negative on either side) around the wires of the circuit to reach the other side of the battery. As it travels through the wires, it powers whatever is connected to the circuit (e.g. a light bulb, a fan, etc.). So, yes, your idea of a battery is correct. The electrolyte is the "wall" and the electrons have to go through the wires (the external circuit) to connect both the terminals. Does this help?
 
  • #4
u0362565 said:
Can I just think of a battery as two separate plates one accumulating positive charges the other negative.
That's more like a capacitor, definitely not a battery.

To expand on the previous answers, a simple way to see a battery is that you take a chemical reaction and split it physically in two parts, to force the electron exchange that would accompany that reaction to take place via a wire.
 
  • Like
Likes ProfuselyQuarky
  • #5
DrClaude said:
That's more like a capacitor, definitely not a battery.
Hmm . . . I never really grasped the main difference between a battery and capacitor aside from the fact that a battery stores chemical energy while a capacitor's potential energy is stored in a electric field. Don't they ultimately do the same things?
 
  • #6
ProfuselyQuarky said:
Hmm . . . I never really grasped the main difference between a battery and capacitor aside from the fact that a battery stores chemical energy while a capacitor's potential energy is stored in a electric field. Don't they ultimately do the same things?

battery can be used as a voltage supply in a circuit while capacitor is used to store charge in an elecrric field. However, capacifor wouldn't work if you will not use AC SUPPLY.
 
  • Like
Likes ProfuselyQuarky
  • #7
Eucliddo said:
However, capacifor wouldn't work if you will not use AC SUPPLY.
Oh! So it doesn't work for a direct current? Thanks, Eucliddo.
 
  • #8
ProfuselyQuarky said:
Oh! So it doesn't work for a direct current? Thanks, Eucliddo.

yup. Capacitor is shorted in DC.
 
  • #9
Eucliddo said:
battery can be used as a voltage supply in a circuit while capacitor is used to store charge in an elecrric field. However, capacifor wouldn't work if you will not use AC SUPPLY.

NO

Eucliddo said:
yup. Capacitor is shorted in DC.

and NO again

please read up on capacitors and how they work

Eucliddo has lead you well astray

ProfuselyQuarky said:
Hmm . . . I never really grasped the main difference between a battery and capacitor aside from the fact that a battery stores chemical energy while a capacitor's potential energy is stored in a electric field. Don't they ultimately do the same things?

yes they can both be used for supplying electrical energy to a circuit. the difference in in how they do that.
Capacitors are often used in electronics for supplying a small current to a circuit that is used to hold data/date time etc info
TV's VCR's, DVD, digital cameras, and a myriad of other devices for when batteries are changed, power cuts etc

A capacitor will only present a short circuit to a DC current during the brief time that it takes to charge up
Once equilibrium has been reached ie, the voltage across the capacitor rises to the supply voltage, current stops flowing into and out of the capacitor and the capacitor appears, as it's circuit symbol suggests, an open circuit
( NOTE, I didn't say through the capacitor ... very important difference)

A capacitor appears to be short circuit in an AC current as the current cycles and the current continuously flows into and out of each plate of the capacitor
( gives the APPEARANCE that current is continuously flowing through the capacitor)Dave
 
  • Like
Likes Jeff Rosenbury and ProfuselyQuarky
  • #10
davenn said:
yes they can both be used for supplying electrical energy to a circuit. the difference in in how they do that.
Capacitors are often used in electronics for supplying a small current to a circuit that is used to hold data/date time etc info
TV's VCR's, DVD, digital cameras, and a myriad of other devices for when batteries are changed, power cuts etc

A capacitor will only present a short circuit to a DC current during the brief time that it takes to charge up
Once equilibrium has been reached ie, the voltage across the capacitor rises to the supply voltage, current stops flowing into and out of the capacitor and the capacitor appears, as it's circuit symbol suggests, an open circuit
( NOTE, I didn't say through the capacitor ... very important difference)

A capacitor appears to be short circuit in an AC current as the current cycles and the current continuously flows into and out of each plate of the capacitor
( gives the APPEARANCE that current is continuously flowing through the capacitor)
Wow, thanks so much, Dave. This helps a lot. I appreciate it! I hope Eucliddo finds it helpful, too :)
 
  • Like
Likes davenn
  • #11
ProfuselyQuarky said:
Wow, thanks so much, Dave. This helps a lot. I appreciate it! I hope Eucliddo finds it helpful, too :)

DC is only used in charging capacitor. When capacitor is put in a circuit (ex. a cascaded amplifier circuit) and Vcc will be a battery, the capacitors will be ignored in computing gain because it's in the OPEN state (I was wrong earlier, Capacitor appears as shorted in AC not in DC). Capacitors need AC supply because it requires frequency which is absent in DC.
 
  • #12
Mr. Dave's explanation is right so I guess that settles it. I was just trying to say earlier that unlike battery, capacitor cannot be used as a first-hand source. It still needs a voltage supply. Since it filters the input depending on the other components present.
 
  • #13
Eucliddo said:
I was just trying to say earlier that unlike battery, capacitor cannot be used as a first-hand source.. It still needs a voltage supply.

consider comparing it to a rechargeable battery, then both of them need an initial voltage supply to charge them up

once disconnected from that supply, they both can then be used as a voltage source
and in that situation, there is no real difference between them as a source.
The difference lies in how the source creates a potential difference
I gave examples for the use of a capacitor in that situation in my earlier post :smile:Dave
 
  • #14
Ok thanks for the comments, i think that's clearer. I found it hard to decipher electric potential and how this is created in a battery.
 
  • #15
Capacitors make poor batteries, but sometimes (very rare) they are used that way.

An example is supercapacitors used to light emergency lighting in aircraft. The capacitor's advantage of not breaking down over years of service exceeds its disadvantage of providing relatively little power since it's only needed for a short time for emergency deboarding.

Mostly they are used for frequency adjustable impedance such as filters or DC blocking.

Batteries are much more complex if for no other reason than there are so many types. Fortunately there's the battery university.
 
  • Like
Likes davenn
  • #16
Jeff Rosenbury said:
Capacitors make poor batteries, but sometimes (very rare) they are used that way.

yes, but the situation has slowly been improving over the years

got a whole bunch of 10F 2.5V ones here if you want to experiment :wink::wink:
 
  • #17
A good battery design maintains an approximately constant voltage as you use it, for most of its capacity.
⏩The biggest problem with using a charged capacitor to supply power is that its voltage inevitably must continuously fall as you drain current from it. So electronic circuits are usually required to compensate for this serious drawback.
 

1. How do batteries store energy?

Batteries store energy through a chemical reaction that occurs between two electrodes, usually made of different metals, and an electrolyte solution. This reaction produces an electrical charge that is stored in the battery until it is needed.

2. How do batteries release energy?

When a circuit is connected to the battery, the stored energy is released as electrons flow from the negative electrode to the positive electrode, creating an electrical current. This current can then be used to power devices such as flashlights, cell phones, and cars.

3. What affects the amount of energy a battery can store?

The amount of energy a battery can store is affected by several factors, including the type of materials used in the electrodes and electrolyte, the size and surface area of the electrodes, and the concentration of the electrolyte solution.

4. How does temperature affect battery performance?

Temperature can greatly affect battery performance. In general, batteries operate best at room temperature, but extreme cold or heat can decrease their efficiency and lifespan. Cold temperatures can slow down the chemical reactions, while high temperatures can speed up the reactions and cause the battery to degrade faster.

5. What is the lifespan of a battery?

The lifespan of a battery depends on several factors, including the type of battery, the materials used, and how it is used and maintained. Rechargeable batteries tend to have a shorter lifespan compared to single-use batteries, and their lifespan can be extended by proper charging and storage techniques.

Similar threads

  • Electrical Engineering
Replies
27
Views
4K
Replies
19
Views
1K
Replies
16
Views
1K
  • Electrical Engineering
Replies
5
Views
1K
Replies
2
Views
2K
  • Electrical Engineering
Replies
5
Views
1K
  • Electrical Engineering
Replies
3
Views
1K
  • Electrical Engineering
Replies
18
Views
2K
Replies
14
Views
2K
Replies
1
Views
768
Back
Top