The Battery Is A Device

Published Date: 02 Nov 2017

Batteries consist of two main types, primary and secondary. primary cells are batteries which cannot be recharged like Alkaline, Lithium Cells, Silver Oxide Cells, and Zinc Air Cells. while secondary cells are rechargeable like Nickel-Cadmium, Nickel-Metal Hydride, Lithium Ion, Lead-Acid, and rechargeable Alkaline. The main difference between them is that primary cells can be stored for longer periods of time than rechargeable batteries and maintain nearly the same capacity as before.

http://chemwiki.ucdavis.edu/Analytical_Chemistry/Electrochemistry/Voltaic_Cells/Case_Study%3A_Battery_Types

Moreover, batteries contains three parts. The first part is the negative part a (anode) , and the second one is the positive part (cathode) ; the third part is electrolyte. The cathode and anode are hooked up to an electrical circuit. When the circuit is closed the electrons will be able to get to the cathode. So, the electrons go through the wire, lighting the light bulb along the way. In sum, by this way, electrical potential causes electrons to flow through the circuit.

Picture : (http://www.qrg.northwestern.edu/projects/vss/docs/Power/2-how-do-batteries-work.html)

All batteries have an internal resistance, and the internal resistance of a battery is defined as the opposition to the flow of current within a battery. There are two basic components that impact the internal resistance of a battery ; they are electronic resistance and ionic resistance. The electronic resistance pulse the ionic resistance will be referred to as the total effective resistance . (Daniel,1961)

The electronic resistance encompasses the resistivity of the actual materials such as the metal covers and the internal components ; as well as , how well these materials make contact with each other . The effect of this portion of the total effective resistance occurs very quickly and can be seen within the first few milliseconds after a battery is place under load . (Daniel,1961)

The ionic resistance is the resistance to current flow within the battery due to various electrochemical factors such as , electrolyte conductivity , ion mobility and electrode surface area . These effects occur more slowly than electronic resistance with the contribulation to total effective resistance typically starting few milliseconds or more after a battery is placed under load. (Daniel,1961)

R=V/A

In many materials, the voltage and resistance are connected by Ohm's Law:

Ohm's Law : V = IR

Using Ohms law, the total effective resistance is subsequently calculated by dividing the change in voltage by the change current.

" As an example, if a 5 mA stabilization load is used in combination with a 505 mA pulse, the change in current is 500 mA. If the voltage changes from 1.485 to 1.378 , the delta voltage would be 0.107 volts , thus yielding a total effective resistance of 0.107 volts/500 mA or 0.214 ohms".

So, the connection between voltage and resistance can be more complicated in some materials. These materials are called non-ohmic

(http://physics.bu.edu/~duffy/PY106/Resistance.html)

In addition , the Internal resistances determine the quality of the battery by that the internal resistance of a battery determines its run time . The lower the internal resistance of a battery, the less power is lost. Also, a high internal resistance means that the battery will provide less power. So as the internal resistance of the battery decreases , less power is lost , and the quality of the battery will be more.

(Daniel,1961)

Furthermore, temperature effects on the battery quality by that battery function best at room temperature, and any deviation towards hot and cold changes the performance. Operating a battery at elevated temperatures momentarily improves performance by lowering the internal resistance and speeding up the chemical metabolism, but such a condition shortens service life if allowed to continue for a long period of time.

Also, as cold temperature increases the internal resistance and diminishes the capacity. Batteries that would provide 100 percent capacity at 27C will typically deliver only 50 percent at 18C. The capacity decrease is momentary and the level of decline depends on the battery chemistry.

In sum, the change in resistance, is proportional to the temperature change. This is reflected in the equations:

"http://buphy.bu.edu/~duffy/PY106/8b.GIF"

http://batteryuniversity.com/learn/article/discharging_at_high_and_low_temperatures

Calendar Life

Picture : http://batteryuniversity.com/learn/article/discharging_at_high_and_low_temperatures

VT (terminal voltage) = the actual potential difference across the terminals of the supply when a current is being supplied. When a closed circuit is set up so that electrons flow from negative to positive terminals, the terminal voltage drops below EMF value.

As a result, when current flows, there is an internal voltage drop equal to ir,

and from this,

VT = ε – Ir

(Holliday,1981)

The amount of work to move a charge from one point to another point is how much potential energy has change. This is the difference in potential energy called potential difference, and the potential difference is measured between two points. In other words, the potential difference across a battery means the energy per unit charge released by the battery to the external circuit.

Unit= Volt(V)

(Honer,2008)

when a resistance is connected across the terminals of a battery. A potential difference is developed across its ends. Current flows from higher potential to lower potential across the resistance by itself. But inside the battery work has to be done to bring the positive charge from lower potential to higher potential. The influence that makes current flow from lower to higher potential inside the battery is the Electromotive force. In other words, Electromotive is not a force measured in newtons but a energy per unit of charge, measured in volts. (Honer,2008)

If w is the work done by battery in taking a charge q from negative terminal to positive terminal, then work done by battery per unit charge emf(E) of the battery.

thus, E=W/q .

(http://farside.ph.utexas.edu/teaching/302l/lectures/node57.html)

\begin{figure} \epsfysize =2.5in \centerline{\epsffile{circuit1.eps}} \end{figure}

 A battery of emf ${\cal E}$ and internal resistance $r$

 connected to a load resistor of resistance $R$.

Picture :(http://farside.ph.utexas.edu/teaching/302l/lectures/node57.html)

Power output means the amount of power a component, circuit or system can deliver to a load. Consider a simple circuit in which a battery of emf ${\cal E}$ and internal resistance $r$ drives a current $I$ through an external resistor of resistance $R$ . The basic purpose of the circuit is to transfer energy from the battery to the load, where it actually does something useful for us .

"The equivalent resistance of the circuit is r + R  so the current flowing in the circuit is given by 

\begin{displaymath} I = \frac{{\cal E}}{r+R}. \end{displaymath}

The power output of the emf is "

\begin{displaymath} P_{\cal E} = {\cal E}\,I = \frac{{\cal E}^2}{r+R}. \end{displaymath}

(http://farside.ph.utexas.edu/teaching/302l/lectures/node62.html)

"The power dissipated as heat by the internal resistance of the battery is 

\begin{displaymath} P_r = I^2\,r = \frac{ {\cal E}^2\,r}{(r+R)^2}. \end{displaymath}

the power transferred to the load is 

\begin{displaymath} P_R = I^2\,R = \frac{ {\cal E}^2\,R}{(r+R)^2}. \end{displaymath}

If \begin{displaymath} P_{\cal E} =P_r + P_R. \end{displaymath}

Then ,some of the power output of the battery is immediately lost as heat dissipated by the internal resistance of the battery. The remainder is transmitted to the load."

(http://farside.ph.utexas.edu/teaching/302l/lectures/node62.html)

 $R=r$. When the resistance of the load matches the internal resistance of the voltage source, means that power transfer between a voltage source and an external load is at its most efficient. If the load resistance lowers, then most of the power output of the voltage source is dissipated as heat inside the source itself. If the load resistance is higher, then the current which flows in the circuit is too low to transfer energy to the load at an appreciable rate.

(http://farside.ph.utexas.edu/teaching/302l/lectures/node62.html)

The battery effect our life in a huge way , and it become an important thing in our life because we use it in every little thing in daily life. For example, because Alkalines provide high-capacity outputs and long shelf lives, we use it in calculators, cameras, clocks and watches. Also, because Lithium batteries carry a 3-volt capacity per cell, we use it in smoke alarms ; on the other hand, . Lead acid batteries carry a 2-volt output per cell, and like lithium batteries, work best with devices like CD players and camcorders which require minimal outputs when used. In addition, dry cell batteries consist of some materials that allow for recharging on a regular basis. Deep cycle cell designs function well as solar electric power sources and generator power sources. In sum, we use batteries in alarm Systems, UPS, medical equipment, emergency lighting, telecommunications, electric vehicles, leisure, mobility, security, toys, flashlights, portable radios, cameras, hearing aids and generator electric power…..

http://www.cs.utexas.edu/~deke/uses of battery /manuals/d600/battery.htm

The batteries contain a toxic amount of substances like nickel, cadmium, mercury, zinc, lead and lithium. These substances can cause health and environmental problems. For example, Improperly discarded batteries leak heavy metals into the soil and the water supplies, put our world at risk of developing health problems, including damage to the nervous system. Also , small amounts of lead can cause permanent lowering of intelligence in children, potentially resulting in reading disorders, psychological disturbances, and mental retardation. Moreover, the thermal inversions associated with large cities can lead to dangerous buildup of photochemical smog air acidification which have an impact on soil and ecosystems.

http://www.osha.gov/SLTC/batterymanufacturing/