Functioning of batteries. Chemical energy to electrical energy (Essay Sample)

Functioning of batteries (Name) (Course) (Institution) (Tutor) (Date) Batteries Chemical energy to electrical energy General overview Batteries are devices that are made of one or more electrochemical cells. The cells carry out the function of converting stored chemical energy into electrical energy. In an overview, a battery has two terminals, a positive and a negative terminal. The positive terminal is referred to as cathode while the negative terminal is referred to as anode. Electrolytes are responsible for current flow. They create a medium of ion transfer between the electrodes and the terminals. This allows the current to flow outside the battery in order to carry out the intended chore (Linden & Reddy, 2003: 10). Batteries are categorized in different levels. There are those that are meant for single use such that after using them, they are disposed. They cannot be used again after using once. This means that the electrode materials cannot be reversed during discharge. Examples of this kinds of batteries are the alkaline batteries, normally used for flashlights and other portable devices. Example of a portable device is a radio. There is also the group of rechargeable batteries normally referred to as secondary batteries. These kinds of batteries are rechargeable upon discharge after use, and they are reusable (Kang & Ceder, 2009: 12). Examples of such batteries are the lithium ion batteries and lead-acid batteries, which normally used in vehicle among many other uses. Lithium ion batteries are those that are used for portable electronics such as phones. Batteries are made assuming many varied shapes and sizes. The assumption is based on the ultimate use of the battery. For instance, a watch will require a small battery that will fit inside it. Car batteries are a bit larger and heavy in weight so that they may be able to hold enough material to generate enough power for vehicle use (Kang & Ceder, 2009: 13). Compared to other fuels, batteries have lower energy specificity. Researchers stipulate that the difference in the two forms of energy bearers is that batteries deliver their energy in the form of electricity. This makes it easy to convert the energy mechanical work when it is stored in the form of electricity. On the other hand, fuels pass through several processes before conversions before mechanical work can be attained. Fuels are used in engines, which derail the efficiency of conversion to work. Example of such fuels is gasoline (Rich, 1994: 31). Primary batteries are capable of releasing current instantly when they are assembled in a complete circuit. Primary batteries are used mostly for alternative power source in areas where power is not sufficient. Their chemical reactions are not reversible after use. Secondary batteries are rechargeable. They are using active materials at their discharged state. To charge them, electric current is applied so that it can reverse the chemical reactions that take place when the battery is in use. Rechargeable batteries are fed with liquid electrolytes. The battery is supposed to be kept upright and be properly ventilated. This ensures that hydrogen gas is dispersed safely during the process of charging. The lead-acid battery used in cars can generate up to 450 amperes of power (David & Thomas, 2002: 15). Other ways of classifying batteries are wet cells and dry cells. The wet cells contain liquid electrolyte. The liquid covers all internal parts of the battery and the gas produced during use escape to the air. Wet cells technology can form both the primary cells and secondary cells. On the other hand, dry cells use paste electrolyte. During manufacture, only enough moisture is left for the sake of current flow. The advantage of dry cells is that they are portable because they do not have wet liquids that may spill (David & Thomas, 2002: 15). Example of a dry cell is the zinc-carbon battery. Its normal voltage is 1.5 volts. The battery is made of a zinc anode and a carbon cathode. The electrolyte is ammonium chloride, which is made in the form of paste. A study conducted by researchers indicates that batteries can be self-discharging. The research states when the battery is not engaged in any work there are some chemical reactions that take place in it. Hence, result in self-discharge. This mostly happens at room temperature (20-20 degrees Celsius) (Rich, 1994: 31). Chemical energy to electrical energy Batteries are made of one or more electrochemical cells. These cells are responsible for storage of energy in chemical form for later conversion to electric energy when needed. Batteries are also made with voltaic cells, which carry out the conversion activity of energy from chemical to electric energy. One can easily confuse the term current and use it to mean voltage, which is not the case. Current is defined as the flow of electrical charge in a circuit; on the other hand, voltage is defined as the amount of current present in a circuit and flows within that circuit in a given period (Kang & Ceder, 2009: 12). The anode is separated from the cathode by the electrolyte. The electrolyte allows the flow of current between the two. When the batteries are put in a complete circuit, there is a chemical reaction emitted as an end reaction on the electrodes. The chemical energy develops a flow of electrical energy to the device completing the circuit. During this activity, the battery undergoes a discharge function. The chemical reacting on the anode phase generate electrons that are developed on the cathode and forms ions in the electrolyte (David & Thomas, 2004: 17). This process is referred to as oxidation reaction. On the other side, the cathode accepts electrons marking the completion of the circuit for electrons flow. The electrode acts as a unitary module for the chemicals from the anode and cathode. The reaction obtained is conversion of chemical energy to electrical energy. The reactions happen simultaneously. During the reactions, ions transport current via the electrolyte while electrons flow in the external circuit. This process leads to electric current generation (David & Thomas, 2004: 17). For disposable batteries, the reaction will take place until the reactants making the cell are consumed to exhaustion. In such batteries, the reaction only flow in one direction. For rechargeable batteries, the reaction runs in two directions. Energy can be changed from chemical form to electrical form and vice versa (Rich, 1994: 32). Compare and contrast the following battery technologies: Carbon-zinc Lead-acid Alkaline (a) carbon-zinc A zinc-carbon battery is a battery that is made in a zinc can that serves as the outer container and negative terminal. The positive terminal is made of a carbon rod. The rod is covered by manganese dioxide and carbon powder mixture. The electrolyte used is a mixture of chloride and ammonium chloride dissolved in water. Zinc-chloride batteries belong to the group of primary batteries. They are also dry cells. They have a low energy density. Normally, the voltage will reduce with usage because electrolyte drops concentration around the cathode. They have a short life because the zinc case is attacked by ammonium chloride. This leads to the zinc metal becoming thinner during usage of battery. During the process, zinc metal is oxidized to zinc ions. Eventually, when the zinc has become thin beyond normal levels, the cell starts leaking out zinc chloride. The battery will have reactions taking place within it for as long as it is manufactured (Rich, 1994: 32). (b) lead-acid In contrast to zinc-carbon batteries, lead-acid batteries are rechargeable meaning they belong to the secondary batteries. This battery has an ability to supply high surge currents. These contrasts zinc batteries because lead acid batteries have a high energy density. At discharged states, both the positive and the negative terminals become lead (II) sulfate. During reaction, the electrolyte will lose sulfuric acid that is already diffused to form water primarily. During discharge, electrons flow from the negative terminals to the positive terminals in the external circuit. When the battery is charged, the cells contain negative terminals made of elemental lead (Pb) and positive terminals made of lead (IV) oxide. The electrolyte is sulfuric acid. During charging, electrons are forced to move from positive plate to the negative plate (Rich, 1994: 33). (c) Alkaline batteries Unlike lead-acid batteries, alkaline batteries are primary batteries. They have a higher energy density as compared to zinc-carbon batteries. They also have a longer shelf life compared to zinc-carbon batteries. Unlike both the two batteries, alkaline batteries have an alkaline electrolyte, which is potassium hydroxide. Zinc carbon has an acidic electrolyte, ammonium chloride. They are dry batteries. The negative terminal is made out of zinc and the positive terminal is made out of manganese dioxide. The electrolyte is made of potassium hydroxide. The electrolyte is not involved in the reaction meaning it remains in its usual state. During the reaction, only manganese dioxide and zinc are involved in the process of discharge. Unlike the other batteries, alkaline batteries capacity is greatly influenced by the use of the battery. The current produced by these batteries are greatly proportional to their sizes. The current technology has made it possible for a discovery of some chargeable alkaline batteries (Rich, 1994: 32-33). Reference list David, L. & Thomas, B. (ed.) (2002) Handbook of Batteries 3rd Edition. McGraw-Hill, New York, 2002 Kang, B. & Ceder, G. (2009) Battery materials for ultrafast charging and discharging. London: Century Business Linden, D. & Reddy, T. B. (ed.) (2003) Handbook Of Batteries (3rd ed.). New York: McGraw-Hill. Rich, V. (1994) The International Lead Trade. Cambridge: Woodhead. source..