Difference Between a Battery and a Capacitor
A Battery and a Capacitor is similar as both store and release the electrical energy and rated in Ah. But, there are some key differences between them which has been discussed in the following post. The main difference between a battery and a capacitor is that Battery stores charge in the form of chemical energy and convert to the electrical energy whereas, capacitor stores charge in the form of electrostatic field.
Battery
A Battery is a device used as source of energy. It has three main parts known as Cathode (Positive Terminal), Anode (Negative Terminal) and a separator known as electrolyte. Battery store energy in the form of chemicals and convert it back to the electrical energy when needed. The chemical reaction called oxidation-reduction takes place in between the cathode and the anode via the separator (electrolyte) during charging and discharging of the battery.
Capacitor
A Capacitor is a two terminal device having two or more parallel layers plates separated by a dielectric medium known as insulator. When voltage applied across the plates of capacitor, current want to flow through it until the voltage across both the negative and positive (Anode and Cathode) plates become equal to the applied voltage (source). The insulating medium in between the two conductive plates of capacitor opposes to the flow of current. This change create an effect which stores in capacitor in the form of electrostatic field.
Supercapacitor
A supercapacitor is also known as Super Cap or Ultra-Capacitor. It is a type of polar capacitor with high capacitance rating but has low voltage rating. Supercapacitor capacitance ranges from 100 F to 12000 F with low voltage ratings approximately 2.5 v to 2.7 v.
Supercapacitor is supposed to be in between a Capacitor and battery. These types of capacitors charge much faster than a battery and charge more than an electrolytic capacitor per volume unit. That is why a supercapacitor is considered between a battery and an electrolytic capacitor.
Main Differences Between a Battery and a Capacitor
The following table shows key differences and comparison between capacitors and batteries.
| Characteristics | Battery | Capacitor |
| Symbol |
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| Definition | Battery stores potential energy in the form of chemical energy which is later converted to the electric energy. | A Capacitor stores the potential energy in the form of eclectic field (electrostatic field) and release to the circuit as electric energy. |
| Construction | Battery has three parts known as Cathode (positive (+ve), Anode (Negative (-ve) and Separator (known as electrolyte). | Capacitor is a simple two terminal device Terminals are metallic plates and there is a dielectric material (insulator) between them. |
| Function | Batteries provide energy to the connected circuits. i.e. Battery generates electrons and charge. | Capacitors draw, store and release the energy. i.e. Capacitor only stores charged electrons. |
| Working Principle | Battery works based on chemical reaction called oxidation-reduction reaction. | When voltage applied across the capacitor terminals, It starts to store energy in it. |
| Operation | Battery Generate Electrons. | Capacitor Store Electrons. |
| Types | Battery types are Alkaline, Lithium Cells, Silver Oxide Cells, Zinc Air Cells, Zinc Carbon, Lead Acid, Lithium Ion (Li-ion), Nickel Metal Hydride (Ni-MH), Nickel Cadmium (Ni-Cd) etc. | Electrolytic, Electrostatic, Electrostatic, Electrochemical, Super Capacitor, Hybrid Super Capacitors, Ceramic Capacitors, Film Capacitors, Tantalum, Integrated Capacitor. |
| Type of Device | Battery is an Active Component. | Capacitor is a Passive Component. |
| AC & DC Usage | Battery is used to provide DC supply. | Capacitor blocks DC supply and pass the AC supply. |
| Voltage Behavior | A battery provides almost constant voltage while discharging. | A Capacitor discharging voltage quickly decreased. i.e. discharge rate is very fast. |
| Potential Difference (P.d) | Constant | Increases exponentially |
| Charging and Discharging | The Charging and Discharging time of a Battery is slow i.e. 10 – 60+ minutes. | Charging and Discharging time of a Capacitor is very fast i.e. 1-10 seconds. |
| Charging Temperature | 0 – 45 °C (32 – 113°F) | -40 to 65 °C (-40 – 149°F) |
| Life Cycle | 500+ Hours | 1M – 3M hours. |
| Service Life | 5-10 Years | 10-15 Years |
| Voltage per Cell | 3.6-3.7 Volts | 2.3 – 2.75 Volts. |
| Specific Power Rating | Battery Specific power rating is about 1k – 3k (W/kg). | Capacitor Specific power rating is about 1M (W/kg). |
| Polarity | Battery polarity reversed during charging and discharging. | Capacitor polarity must be same during charging and discharging. |
| Size | For the same charging capacity, Battery size is small as compared to a capacitor. | Capacitor size is large as compared to a battery for same capacity rating. |
| Cost | Cost of Battery is higher. | Cost of Capacitor is Less. |
| Advantages |
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| Disadvantages |
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| Applications |
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FAQ
What are two main differences between a capacitor and a battery?
battery A device that can convert chemical energy into electrical energy. capacitor An electrical component used to store energy. Unlike batteries, which store energy chemically, capacitors store energy physically, in a form very much like static electricity
Can I use a capacitor as a battery?
A super capacitor normally has a capacitance of between 1 to 3000 farads, which make them good substitutes for batteries! We are going to safely charge 2x 400 farad capacitors in series up to 5.4VDC, and feed that voltage through a DC-DC booster circuit
What is the difference between a battery and a supercapacitor?
What is the difference between a battery and a supercapacitor? Batteries are known for their high energy density whereas supercapacitors can deliver power almost immediately — a quality that is highly desirable in backup power applications where response time in the event of a power outage is critical
Why are capacitors not batteries?
Unlike batteries, which store energy through chemical reactions, supercapacitors store the majority of their energy electrostatically. As a result, they can charge and discharge energy much faster than batteries, with power densities typically 10 times greater
What is the disadvantage of a capacitor vs battery?
Here are some disadvantages of supercapacitors: Self-discharge rate. Supercapacitors aren’t well-suited for long-term energy storage. The discharge rate of supercapacitors is significantly higher than lithium-ion batteries; they can lose as much as 10-20 percent of their charge per day due to self-discharge
Is A capacitor faster than a battery?
This makes capacitors very fast at charging and discharging, much faster than batteries. They are essential for applications where rapid bursts of current are needed, such as camera flashes
Can a capacitor work without a battery?
So yes you don’t need a battery to use a capacitor. If you don’t have a circuit to place it in it’s totally useless
Can we replace battery with capacitor?
Supercapacitors can be charged and discharged millions of times as opposed to batteries who can a few thousand at best. Yes, you can replace a battery with a capacitor
Is a phone battery a capacitor?
No, although a phone may contain capacitors, the main battery of a cell phone is typically a lithium-ion or similar chemistry battery. Capacitors at the moment don’t have anywhere near the same ability to hold energy as modern batteries do, and a phone powered entirely by capacitors would run for a few minutes at best
Why don’t cars use supercapacitors?
Super capacitors are more power dense than Lithium Ion, but less energy dense. This means they can provide a much higher discharge current than a lithium ion battery, but they’re not that good at storing a lot of energy
