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===Type 2: Zinc-Carbon Batteries===
===Type 2: Zinc-Carbon Batteries===
<br>Zinc carbon batteries use carbon and magnesium dioxide (MnO2) as the cathode and zinc as the anode. A brass strip connects the cathode to the negative terminal and the solid zinc anode is connected directly to the positive terminal. Zinc 2 clorite (ZnCl2) is use as an electrolyte. Older zinc carbon Batteries may contain small amounts of lead or cadmium in the anode <ref>A.M. Bernardes et al. (2004)</ref>
<br>Zinc carbon batteries use carbon and magnesium dioxide (MnO<sub>2</sub>) as the cathode and zinc as the anode. A brass strip connects the cathode to the negative terminal and the solid zinc anode is connected directly to the positive terminal. Zinc 2 clorite (ZnCl2) is use as an electrolyte. Older zinc carbon Batteries may contain small amounts of lead or cadmium in the anode <ref>A.M. Bernardes et al. (2004)</ref>


===Type 3: Nickel Cadmium (NiCd)===
===Type 3: Nickel Cadmium (NiCd)===

Revision as of 23:53, 22 April 2010

Template:Engr410inprogress


"Borrowed/Adapted" from http://www.appropedia.org/305_literature_review_template

Intro


This is a review of the available literature pertinent to a life cycle analysis of standard and rechargeable, closed cell batteries such as AA, AAA, or 9V.

Battery Basics

There are two main types of batteries: dry-cells and wet-cells. The three primary parts to a dry-cell battery are the electrolytic paste, electrode and the canister to contain it all. The electrode is a non-conductive carbon rod separating the anode (negatively charged side) and the cathode (positively charged side). The free electrons, available from the chemical reaction within the electrolytic paste, are collected in the anode but attracted to the cathode. However, the construction of the battery resists the electrons from reaching the cathode unless a circuit, external to the battery, is completed. This results in a current, much like the current in a river when water is allowed to flow downhill due to elevation potential. The electric potential formed by closing the circuit allows flow of electrons from the anode to the cathode; the current can then be used to deliver energy to an appliance, such as a flashlight. The difference in charge between the anode and cathode is the potential or voltage of the battery. Voltage affects the flow or current of electrons through the circuit. [1].

Primary vs. Secondary


The types of dry cell batteries considered in the LCA can be further divided into primary (single-use) and secondary (rechargeable) types; the difference is in the ability for battery recharged after initial use. Primary cells are manufactured at full charge. Once a primary battery is discharged it cannot be recharged due to the irreversible nature of the electrochemical reaction which is used in this type of battery. Secondary batteries are not always manufactured at full charge and can be recharged by the user a number of times. While the reversible nature of secondary batteries allows them to be recharged, the composition of their active chemicals degrades with use, resulting in a finite number of recharge cycles. Secondary cells will accept charge for many cycles but because their storage capacity decreases with each cycle the number of useful cycles is limited. [2]

Types of batteries


This section covers some of the more common types of primary and secondary batteries that are considered in the LCA. These types were chosen because they are some of the most used and are for the most part interchangeable in their application. [3]

Type 1: Alkaline Batteries


Alkaline batteries use carbon and magnesium dioxide (MnO2) as the cathode and powdered zinc as the anode. A steel case and brass strip connect the cathode and anode respectively to the batteries terminals. An alkaline paste of potassium hydroxide (KOH) is used as an electrolyte.[4]

Type 2: Zinc-Carbon Batteries


Zinc carbon batteries use carbon and magnesium dioxide (MnO2) as the cathode and zinc as the anode. A brass strip connects the cathode to the negative terminal and the solid zinc anode is connected directly to the positive terminal. Zinc 2 clorite (ZnCl2) is use as an electrolyte. Older zinc carbon Batteries may contain small amounts of lead or cadmium in the anode [5]

Type 3: Nickel Cadmium (NiCd)


Nickel Cadmium batteries use a cadmium cathode and a nickel hydroxide anode. The electrolyte used is a mixture of potassium hydroxide (KOH) and lithium hydroxide (LiOH).[6]

Life Cycle Analysis Results/methods

A life cycle assessment or analysis is important for comparing, equally, the impacts of two similar products or services. In this case, the comparison between single-use, also called primary batteries, such as alkaline and rechargeable or secondary batteries such as Nickle-Cadmium (Ni-Cd), Nickle Metal Hydride (Ni-MH) or Lithium Ion (Li-ion) is studied from available literature. This LCA examines only consumer batteries common in toys and small electronic devices such as 'AA' and 'C' batteries. Some considerations in all stages of the life of a battery include[7]:

PED (Primary Energy Demand): total amount of primary energy extracted from the earth (in MJ).
GWP (Global Warming Potential): contribution to the GW of the atmosphere by the release of specific gases (in kg CO2 equ.)
ODP (Ozone layer Depletion Potential): contribution to the depletion of the stratospheric ozone by the release of specific gases (in kg R11 equ.)
AP (Acidification Potential): acidification by gases released to the atmosphere (in kg SO2 equ.),
EP (Eutrophication Potential): water enrichment in nutritive elements by the release of specific substances in the effluents (in kg PO43- equ.)
WD (Water Depletion): consumption of water (in kg H2O).

For the most effective and comparable analysis, each comparison must be normalized to compare "apples to apples." Energy is a good metric to normalize by; for instance megajoules (MJ) can be used to represent the energy required to manufacture a given weight of batteries, the energy required in diesel combustion to transport a given weight or the energy required to recycle a given weight of batteries. For this life cycle it is easiest to normalize everything on a gram per megajoule (g/MJ) basis.

Manufacturing

In addition to the materials a battery is made of, material and energy is also consumed in the production of batteries. Manufacturing equipment must be run, maintained and eventually replaced all of which incur material costs outside of the materials that end up in the battery. These materials can be diverse in the case of battery manufacture. For the comparison of the selected types of primary and secondary battery, a comparison is made between $100 million in primary and $100 million in secondary See the table to the right [8].

Manufacturing Resources.jpeg

The table makes the assumption that secondary batteries cost four times primary batteries. For this direct comparison primary batteries use less resources in manufacture than secondary in most categories. The table also makes a comparison taking into account the ability of secondary batteries to be used multiple times. The assumption that is made is that a secondary battery can replace a primary battery for 200 cycles[9]. Under this assumption secondary batteries have a much larger advantage in manufacturing resources. This advantage is entirely dependent on the proper use of secondary batteries. Another consideration in the production of batteries is that limits in manufacturing and recycling technologies often do not allow for recycled materials to be used. This need for pure resources often requires the extraction of new resources [10].

Distribution/transportation

Battery Size Chart.JPG

The impacts from distribution and transportation of both new and recycled batteries is primarily a function of weight. The truck hauling the cargo is limited by weight. Heavy trucks can carry more than medium trucks but use more fuel to go the same distance. Since both single-use (primary) and rechargeable (secondary) batteries are comparable in size, the number of batteries you can fit in a container or on a truck is comparable. The variable is weight, which is directly proportional to the chemical process of combustion in the engine that converts to kinetic energy of the truck carrying the cargo. The comparison of weights between Ni-Cd and Ni-MH are shown in the thumbnail to the right. The average weight for all sizes of Ni-Cd is 40.15 grams and the average miliamp-hour (mAhr) per weight (gram) is 31.21 mAhr/g. Respectively, for Ni-MH the averages are 42.60 grams and 48.36 mAhr/g [11]. Since the Ni-MH is heavier but delivers more current per weight during use, a standard that is appropriate for normalizing transportation of batteries is mAhr/gram/MJ, where MJ is the energy in the diesel used to transport the batteries. Therefore, a medium truck from Los Angeles to Arcata (~800 km) that consumes 6.8 MJ per metric tonne per kilometer (MJ/t-km)[12] a tonne (1000 kg) of Ni-Cd batteries require an average of 1.7(10)^-4 MJ/mAhr or 0.17 kJ/mAhr while Ni-MH requires 1.12(10)^-4 MJ/mAhr. Therefore NiMH is a better option since less energy is required to get it the same distance. The inverse of this says that for Ni-MH 8.89 Ahr can be transported per MJ of energy from diesel combustion. Now let's try this same comparison between Ni-MH and alkaline (primary) batteries . . . .

Use

Battery charger components.JPG

The use of batteries do not have a very large impact as long as they are treated properly. Many battery manufacturers warn that "most of the problems with rechargeable batteries can be traced to misuse" [13] [14] A misuse that results in a leak most commonly occurs from: (1) overuse, i.e. being forced to overdraw the energy storage capacity, (2) being heated above the batteries threshold or (3) corrosion of the shell from water vapor in the air over long time periods. Another contribution to the life cycle of rechargable batteries that is worth noting includes the charger and its components. The table to the right shows the components of a battery charger. [15]

Recycling

Disposal

Transportation of used batteries has huge impacts
-Recycling batteries shown to be better

Notes

  1. Progressive Dynamics
  2. A.M. Bernardes et al. (2004)
  3. A.M. Bernardes et al. (2004)
  4. A.M. Bernardes et al. (2004)
  5. A.M. Bernardes et al. (2004)
  6. A.M. Bernardes et al. (2004)
  7. McDowell, J. and Siret, C.
  8. Lankey, R.L. and McMichael, F.C. (2000)
  9. Lankey, R.L. and McMichael, F.C. (2000)
  10. McDowell, J. and Siret, C.
  11. Batteries Wholesale (2005)
  12. Gleick, P.H. and Cooley, H.S. (2009)
  13. Batteries Wholesale (2005)
  14. Lankey, R.L. and McMichael, F.C. (2000)
  15. Parson, David (2006)"The Environmental Impact of Disposable Versus Re-Chargeable Batteries for Consumer Use" LCA Case Studies

References

  • A.M. Bernardes, D.C.R. Espinosa, J.A.S. Tenório (2004) ”Recycling of batteries: a review of current processes and technologies” Journal of Power Sources No. 130 291–298.
  • Batteries Wholesale (2005) "Capacity vs. Weight, accessed 3/17/10 from www.batterieswholesale.com/capacity_weight.htm
  • Batteries Wholesale (2005) "Damaging Batteries," accessed 3/17/10 from www.batterieswholesale.com/damaging_batteries.htm
  • >Gleick, P.H. and Cooley, H.S. (2009) "Energy Implications of Bottled Water" Environ. Res. Lett. 4 014009 (6pp)"
  • Lankey, R.L. and McMichael, F.C. (2000)"Life-Cycle Methods for Comparing

Primary and Rechargeable Batteries," Environ. Sci. Technol., No 34, pp. 2299-2304

  • McDowell, J. and Siret, C. (date unknown)"Energy-Saving Batteries – Green or Greenwash?,"
  • Progressive Dynamics (Date Unknown) "Battery Basics," accessed 3/1/10 from www.progressivedyn.com/battery_basics.html

Notes(for editors)


Brett - Types of batteries and manufacturing
James - use and distribution
Ryan - recycling and disposal
http://en.wikipedia.org/wiki/Wikipedia:CITE#Inline_citations

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