September 2006 – Battery Education

iPod Battery Capacity

In my last article about the 24 Hour iPod Battery we discussed the true capability of such an iPod battery. Now however, I wanted to speak directly about the primary limitations of current battery technology that makes it difficult to truly get an iPod battery to last 24 hours given the multifaceted demands of consumers. Question: can an iPod battery power your iPod with 24 hours of music playback, a bright screen, cycling through your music files while all the while you are connecting external devices to your iPod? I do not believe so and the testimonies of thousands of iPod users support my belief. Now we must question why?

The reason why an ipod battery may not perform as specified when your average consumer is using thier iPod is due to the limitations of the iPod batteries themselves, specifically the limitation of capacity. All iPod batteries including the (iPod 3rd Gen Battery, iPod Mini Battery, iPod Nano, Battery, iPod Video Battery, iPod Photo Battery, iPod 4th Gen Battery, iPod Shuffle, and iPod Classic Battery) have all been specifically designed for a battery rating that will perform a single function – to power their intended iPod Player. Battery Ratings will look very similar to:

IPOD MINI BATTERY
PART # EC003
3.7 VOLTS
550 mAh

The battery rating number that defines battery capacity in the example above is the 550 mAh (milli Amp hours). To understand, battery capacities, then we need to follow some basic electronic formulas. First however let’s define battery capacity as a reference to the total amount of energy stored within a battery. As I alluded to above battery capacity is rated in Ampere-hours (Ah).

Amp hours – or Ah – measures capacity. That is what we want to know about iPod Batteries – how long can it deliver a certain amount of charge before it runs out. As with all metric measurements, Amps can be divided into smaller (or larger) units by adding a prefix.

In the case of our example above a milliAmp hour (mAh) is most commonly used on iPod battery specs. Note that 1000 mAh is the same a 1 Ah. (Just as 1000mm equals 1 meter.) iPod batteries with a 1 Amp hour rating could deliver ½ Amp of current for 2 hours, or they could provide 2 Amps of current for ½ hour.

Ampere-hours (Ah) are the product of: Ah= Current X Hours to Total Discharge

The capacity is normally tested or compared with a time of 20 hours and at a temperature of 68F (20C).

Five Factors that Govern iPod Battery Capacity

Physical Size – the amount of capacity that can be stored in the casing of any battery depends on the volume and plate area of the actual battery. The more volume and plate area the more capacity you can actually store in a battery.

Temperature – capacity, energy store decreases as a battery gets colder. High temperatures also have an effect on all other aspects of your battery.

Cut off Voltage – To prevent damage to the battery and the device batteries have an internal mechanism that stops voltage called the cut-off voltage, which is tpically limited to 1.67V or 10V for a 12 Volt battery. Letting a battery self-discharge to zero destroys the battery.

Discharge rate – The rate of discharge, the rate at which a battery goes from a full charge to the cut off voltage measured in amperes. As the rate goes up, the capacity goes down.

Battery History – Deep discharging, excessive cycling, age, over charging, under charging, all reduce capacity. Note charging your battery 1 time will reduce capacity as much as 15%-20% depending on your battery's chemistry.

Until next time, Dan Hagopian www.batteryship.com
Copyright © BatteryEducation.com. All rights reserved.

The 24 Hour iPod Battery

The 24 hour iPod Battery: Fact or Fiction? It would be great if our iPods could play non-stop for 24 hours but is it really possible that such a battery exists? Apple has just introduced the completely remastered iPod Nano. The new Nano is more of the same with the exception of its new ability to hold up to 2,000 songs and can come to you in 5 new colors.

Apple’s marketing spin touts that the remastered iPod Nano, with its new anodized aluminum enclosure and rounded edges, makes the iPod nano look as dazzling as it feels. Apple says the new iPod Nano is sleeker than ever—3.5 inches tall, 1.6 inches wide, and just over quarter of an inch thin. Plus with the iPod Nano’s brighter color screen, album art & photos gain even more brilliance thanks to a 1.5-inch color display that's 40% brighter than before. The new iPod Nano’s can come in silver, green, pink, blue, and black.

Apple also announced new movie downloads from their iTune service. You can buy and download movies starting at $10.00. The final announcement from Apple is that they unveiled a new 80 Gb iPod Video player.

All of these new announcements would be great if they were coupled with a practical 24 hour battery life for watching those movies and listening to those iTunes and MP3 files! The reality is contrary to that! For example:

The ipod battery life of an ipod classic with a 2200 mAh, measured in hours is UP TO 20 hours, or 79% longer than the original ipod classic battery.

The ipod battery life of an ipod 3rd gen with a 850 mAh, measured in hours is UP TO 13 hours or 35% longer than the original ipod 3rd gen battery.

The ipod battery life of an ipod 4th gen with a 830 mAh, measured in hours is UP TO 12 hours or 32% longer than the original ipod 4th gen battery.

The ipod battery life of an ipod mini with a 500 mAh, measured in hours is UP TO 6 hours or 25% longer than the original ipod mini battery.

The ipod battery life of an ipod photo with a 900 mAh, measured in hours is UP TO 14 hours or 29% longer than the original ipod photo battery.

When considering battery life claims remember to consider just like Apple’s legal team is careful to stipulate that the real nature of iPod Batteries is that the iPod battery can power iPods “Up to” the indicated times with music playback only. Also like Apple’s legal stipulations “Rechargeable batteries have a limited number of charge cycles and may eventually need to be replaced and that battery life and number of charge cycles vary by use and settings.”

The legal stipulation that Apple makes clear can be broken down as follows:

First, rechargeable iPod batteries once their useful life is complete will stop working. This is no surprise since a battery is a device that stores chemical energy and through an electrochemical process (electromotive force) converts the stored chemical energy into electric energy via a direct current. The chemical conversion is a process of chemical change created by adding or losing chemical substances (electrons, oxygen, lithium etc.) inside the battery and used by a connecting iPod. As the chemical conversion begins a reaction produces an electron flow. Once the chemical is activated oxidation and reduction occurs and the flow of electrons takes place, thereby creating a direct electrical current. Considering that electrons flow 62 quintillion per second (62,000,000,000,000,000,000 electrons per second) then it takes only a very small moment for power to be created and here is the kicker – the only way to stop is to let the chemical exhaust itself! The chemical inside the iPod battery can be activated by placing a load on the battery (i.e. by connecting your battery to a device regardless if the device is turned on). Once the load is placed on the iPod battery electrons collect on the negative electrode, when an electrolyte separates and conducts electrons between the negative electrode and the positive electrode. This flow creates a current. The electron current, or electricity, can then be directed to an iPod and used as a power stream. Once electrical current is established then the only way to stop it is to let the chemical degrade to the point where the capacity is almost non-existent. This is called battery degradation and begins once the chemistry has been activated. Battery degradation is the normal wear and tear effect of battery usage and its inevitable effects are declining capacity, increasing internal resistance, elevated self-discharge, and premature voltage cut-off on discharge.

Second, iPod Battery life and number of charge cycles vary by use and settings. What this means is that Apple designed the iPod battery to power an iPod under specific conditions (i.e. controlled test conditions). From those tests Apple made their claim about the iPod battery life span. There is nothing wrong with this whatsoever; however what is critical to remember is that consumers don't live in a controlled test environment. Having worked with hundreds of thousands of battery users I can tell you confidently that every user of rechargeable battery devise (i.e. iPods, PDAs, Laptops, DVD Players, Cameras, Cellphones) user their device slightly different. These differences impact how long or how little your rechargeable battery will last. This is a fact. You can test this yourself by using your iPod battery in different tests and time each test to see how long your battery will last. It will be different each time.

But regarding Apple’s iPod battery life claim the key phrase to remember is "up to". So even if the battery lasts an hour Apple is legally covered!

For example Apple claims that the 30GB iPod Video will play music for 14 hours, photo and music slideshows for 3 hours, and iPod on-screen video for 2 hours. In a iLounge test they found that the new iPod Video played music for 15 hours and 30 minutes, photo slideshows for 2 hours and 32 minutes, on-iPod video for 2 hours and 10 minutes, and iPod-to-TV video for 3 hours and 10 minutes.

Apple also claims that the new 60GB iPod will play music for 20 hours, photo and music slideshows for 4 hours, and video for 3 hours. Again in In a iLounge test they found that the new iPod Video played music for 19 hours, 50 minutes, but exceeded Apple’s photo and video claims, playing a music photo slideshow for 4 hours, 47 minutes, iPod-screen video for 3 hours, 23 minutes, and on-TV video for a hefty 5 hours and 24 minutes.

But again everyone may experience slightly different battery life play times. For example here is a situation from a user quoted from the Apple fourms:

"It is clear that when you use the click wheel a lot, you assume that your battery life gets smaller quickly. I had a problem with my ipod 5G 30Gb battery life : Firstly, I charged it (as soon as i received it) until the plug icon appeared on the screen (1h 30mn) . Then I listened music 'til it was fully discharged. The battery life was approximately 8hrs. Then, this battery life decreased to 5hrs last day. I called Applecare ; the guy told me to restore my ipod, then to let it discharge fully, and to refill it for 4 hrs even if the plug icon appear on the ipod screen. After that, I synchronized ipod to itunes and let it play all night long to see the battery life now. It played music with default settings during 15hrs 'til it shut down. These are the Apple specifications for that ipod. My problem wasn't the battery, but the battery life calibration, which has not been done as it should."

The reality is all batteries including batteries designed specifically for iPods (regardless of generation) have a certain amount of capacity and once the full amount of the capacity has been used then your battery will stop working. This is the normal function of battery design.

In fact consider this taken from Apple iPod Warranty Care: "Your one year warranty includes replacement coverage for a defective battery. You can extend your coverage to two years with AppleCare Protection Plan. During the second year, Apple will replace the battery if it drops below 50% of its original capacity. If it is out of warranty, Apple offers a battery replacement for $59, plus $6.95 shipping. Apple disposes your battery in an environmentally-friendly manner." So basically Apple is correctly telling you that your battery will die with time and use. No questions about that; and that Apple is telling you that your battery replacement plan will cost you a total of $59, plus $6.95 shipping. Folks: iPod batteries can be bought for $9.99 depending on your iPod model.

The admittance by Apple that your ipod battery will eventually die is based on real limitations of the battery's internal design specifically the iPod battery’s capacity.

Until next time – Dan Hagopian, www.batteryship.com
Copyright © BatteryEducation.com. All rights reserved.

Buying Batteries – Brand New, Used or Refurbished?

When buying a battery for your mobile device (PDA, iPod, Digital Camera etc.) make certain you are only buying new batteries – never buy a used or refurbished batteries!

Why? The answer to that is analogous to the question ‘Would you Buy a Half Eaten Sandwich?’ The answer undoubtedly is no! Let me explain…

A battery is a device that stores chemical energy and through an electrochemical process (electromotive force) converts the stored chemical energy into electric energy via a direct current. The chemical conversion is a process of chemical change created by adding or losing chemical substances (electrons, oxygen, lithium etc.) inside the battery and used by a connecting device (i.e. PDA, iPod, Digital Camera).

Inside the battery as the chemical conversion begins a reaction produces an electron flow. If the electrons are not flowing between the anode, cathode, and electrolyte then the battery can sit on the shelf for a year or more. However, once the chemical is activated oxidation and reduction occurs and the flow of electrons takes place, thereby creating a direct electrical current. Considering that electrons flow a 62 quintillion per second (62,000,000,000,000,000,000 electrons per second) then it takes only a very small moment for power to be created and here is the kicker – the only way to stop is to let the chemical exhaust itself!

How is the chemical inside my battery activated? The technical answer is by placing a load on the battery (i.e. by connecting your battery to a device regardless if the device is turned on). The basic operation is that electrons collect on the negative electrode, when a substance (i.e a wire, an electrolyte) is placed as a separator between the negative electrode and the positive electrode the electrons flow (are drawn) to the positive electrode. This flow creates a current. The electron current, or electricity, can then be directed to a device and used as a power stream.

Once electrical current is established then the only way to stop it is to let the chemical degrade to the point where the capacity is almost non-existent. This is called battery degradation and begins once the chemistry has been activated. Battery degradation is the normal wear and tear effect of battery usage and its inevitable effects are declining capacity, increasing internal resistance, elevated self-discharge, and premature voltage cut-off on discharge.

Because of these things you do not want to buy a used battery or a refurbished battery.

Until next time, Dan Hagopian www.batteryship.com
Copyright © BatteryEducation.com. All rights reserved.

The Battery – Cathodes, Anodes, and Electrodes (Part 2 of 2)!

In part 1 of “The Battery – Cathodes, Anodes, and Electrodes” we discussed how engineers manufacture disequilibrium to create free negative electrons so that the positive atoms will attract the electrons at the positive electrode, thereby creating an electron flow. We spoke about electrodes and their function in receiving electrons, and we spoke about the how a direct current is created in a battery. Now in part 2 of this report I will look closer at the electrodes and their effect on the flow of electrons.

Collectively the anode and the cathode are called the electrodes. What is positve and what is the negative terminal. It would be great to simply say that the anode is negative and the cathode is positive, however, that is not always the case. Somtimes the opposite is true depending on battery technology. Moving past this debate the positive electrode can be a lithium cobalite composite (LiCoO2) and the negative electrode can be a carbon-graphite composite.

If we can define an anode we would say that the anode is the electrode at which electrons come up from the battery cell and where oxidation occurs. One side bar is that battery manufacturers in the United States regard the anode as the positive electrode, even though that is technically incorrect, however it does help resolve the problem of which electrode is the anode in a rechargeable cell (or secondary cell) which battery manufactures work with daily.

The cathode on the other hand could then be defined as the electrode at which electrons enter the cell and reduction occurs.

One point that was a challenge for me to grasp was that the each electrode may become either the anode or the cathode depending on the flow of the electrons. In part 1 of this report we learned that positive atoms attract electrons from negative charged atoms to balance the positive atoms. The attraction creates an electron flow, flowing at a speed of 62,000,000,000,000,000,000 electrons per second (62 quintillion electrons per second)! These electrons flow on ions from the anode–to–cathode outside of cell and from cathode–to–anode inside a cell, which results in two types of current [a negative ion (anion) flow and positive ion (cation) flow. The two currents flowing from anode to cathode result in a network of electron flow.

As mentioned earlier the positive electrode can be a lithium cobalite composite (LiCoO2) and the negative electrode can be a carbon-graphite composite. But what is key is that in commercial battery cells, the cathode’s active material is a litiated transition-metal oxide such as lithium cobalt oxide. Because lithium is more electropositive then hydrogen, the electrolyte must be nonaqueous and aprotic. A representative formulation is a solution (1:1 by volume) of ethylene carbonate and propylene carbonate containing a suitable lithium salt such as lithium hexaflourophosphate, LiPF6, which raises the conductivity of the electrolyte. A separator of electrolyte, made of polyolefin such as micropourous polypropylene, is placed between the electrodes for safety. If the electrolyte temperature exceeds a certain value the separator melts and current flow ceases. The cells reaction is the formation of lithium cobalt oxide.

From part 1 and part 2 of “The Battery – Cathodes, Anodes, and Electrodes” we have larned that at work inside your battery is some really incredible activity – a power source that is really rather marvelous when considered thoughtfully.

Until next time, Dan Hagopian www.batteryship.com
Copyright © BatteryEducation.com. All rights reserved.

The Battery – Cathodes, Anodes, and Electrodes (Part 1 of 2)!

A battery as we know it is a device that stores chemical energy and through an electrochemical process (electromotive force) converts the stored chemical energy into electric energy via a direct current voltage. The chemical conversion is a process of chemical change created by adding or losing chemical substances (electrons, oxygen, lithium etc.) inside the battery and used by a connecting device (i.e. PDA, iPod, Digital Camera).

A battery cell is the most basic electrochemical unit and often time cells are stacked on top of one another to meet a specific energy design or need, however, when we are speaking of battery cells we refer to them as a battery whether there is one cell, three, or more in a series.

Within each battery cell are three basic components: the anode, the cathode, and an electrolyte solution. Just to be clear every battery design does indeed have more components contained in the battery then the three listed above, however, the electrodes and the electrolyte are the very basic components of all batteries. In this 1of 2 article report however we are going to focus specifically on the cathode and the anode, commonly referred to as the electrodes.

Batteries power devices by the creation of direct electrical current drawn from the flow of electrons, flowing back and forth between the electrodes. The basic format is that electrons collect on the negative electrode, when a substance (i.e a wire, an electrolyte) is placed as a separator between the negative electrode and the positive electrode the electrons flow (are drawn) to the positive electrode. This flow creates a current. The electron current, or electricity, can then be directed to a device and used as a power stream.

The reason why electrons flow is part of the atomic design. Electrons spin around the center, or nucleus, of atoms, in the same way the earth spins around the sun. The nucleus is made up of neutrons and protons. Electrons contain a negative charge, protons a positive charge. Neutrons are neutral — they have neither a positive nor a negative charge.

There are many different kinds of atoms, one for each type of element. An atom is a single part that makes up an element. There are 118 different known elements. The mass accumulation of elements makes up every thing we can see, touch, hear, and smell (elements are even in things we can’t see).

Each atom has a specific number of electrons, protons and neutrons. But no matter how many particles an atom has, the number of electrons usually needs to be the same as the number of protons. If the numbers are the same, the atom is called balanced, and it is very stable.

Some kinds of atoms have loosely attached electrons. An atom that loses electrons has more protons than electrons and is positively charged. An atom that gains electrons has more negative particles and is negatively charge. A "charged" atom is called an "ion."

The very nature of a positive atom is that a positive atom attracts electrons from negative charged atoms to in effect balance the positive atoms. Why, not sure, and for this article not pertinent. What is necessary to know is that the flow of electrons to positive charged atoms is essential for a direct electrical current.

You see electrons can be engineered to move from one atom to another. When those electrons move between the atoms, a current or flow of electricity is created. The electrons move from one atom to another in a "flow." One electron is attached and another electron is lost. This creates a continual equilibrium amongst the atoms.

Engineers manufacture disequilibrium to create free negative electrons so that the positive atoms will attract the electrons at the positive electrode, thereby creating an electron flow or electrical current. When electrons move from atom to atom a current of electricity is created. This is what happens in a piece of wire. The electrons are passed from atom to atom, creating an electrical current from one end to other end.

Inside the battery itself, is a chemical reaction that produces the electrons. If the electrons are not moving then the battery can sit on the shelf for a year. Once the chemical is activated and the flow of electrons takes place, even for a moment then the loss of power begins and there is no stopping it. This is why you never want to buy a used battery.

Lithium Solid Polymer Electrolyte Batteries

If you have ever owned a PDA, iPod or any other small electrical device the battery power more often then not incorporated a technology called lithium polymer. For example take a look at these HP Compaq iPAQ Batteries at http://www.batteryship.com/htmlos/htmlos.cgi/batteryship/catalog.html?search=ipaq&lp=1&pt=HP+Compaq+iPAQ+Batteries.

As you see many of these batteries like many other batteries found at BatteryShip.com incorporate a technology that is absolutely amazing as it is functional. This amazing technology is contained in the electrolyte solution that is the conducting medium of the battery and the enabler of the direct current (where volts come from in the battery) to power your electronic device. What is so amazing about it is that the conducting metal gel which is enabling the current to flow to and from the electrodes is only tens of micrometers wide (that is smaller then one of your strands of hair)!

A battery as we know it is a device that stores chemical energy and through an electrochemical/electromotive force converts the stored chemical energy into electric energy via a direct current voltage. A battery cell is the most basic electrochemical unit. When we speak of battery cells we know them as a battery whether there is one cell or three in a series.

A battery cell has three basic parts: the anode, the cathode, and an electrolyte solution. In this article we are going to focus specifically on the electrolyte.

The electrolyte solution is a chemical compound (salt, acid, or base) that when dissolved in a solvent forms a solution that becomes an ionic conductor of electricity. In the battery cell the electrolyte solution is the conducting medium in which the flow of electric current between the electrodes takes place by the migrating electrons.

Since the 1970 it has been known that adding salts to polymers can enable the polymer to conduct lithium ion. The material thus can serve as an electrolyte in lithium batteries. Lithium solid polymer electrolyte batteries, when given full measure to the capacity for miniaturization of a fully solid state battery can have the highest specific energy and specific power of any rechargeable technology.

Some of the benefits that lithium solid polymer electrolytes offers are:

ease of manufacturing
immunity from leakage
suppression of lithium dendrite formation
elimination of volatile organic liquids
mechanical flexibility.

It is in the mechanical flexibility that makes batteries with a lithium solid polymer electrolyte most incredible. The capability of a lithium solid polymer electrolyte to be flexible allows the rechargeable technology to fit in the smallest of systems. With battery designs smaller then a less than half the size of a credit card, the flexibility aspect of the polymer allows the electrolyte to incorporate a multilayer laminate of thin films of metal, polymer, and ceramic, measuring tens of micrometers in thickness (the human hair is about 50 micrometers wide) which can deliver the highest specific energy and specific power of any rechargeable technology of its miniature size. To understand the how amazing this technology is imagine thin gel like metal smaller then the width of your hair that not only can bend, stretched, and wrapped but can also deliver enough electrical charge to power your iPod, PDA, or Digital Camera and then you will begin to understand the incredible capability of this technology.

What You Need To Know About Lithium Ion Batteries

Used for many popular handheld devices from iPods to iPAQs lithium-ion batteries are ideal for mobile electronics. They are lightweight, energy-dense, and have a chemistry composite allowing the battery to recharge fast. But what is lithium, where does it come from, how is it made into a battery, what does it look like, and where can I get it?

Here is a quick list of the chemical characteristics of lithium

Name: lithium
Symbol: Li
Atomic number: 3
Atomic weight: [6.941 (2)] g m r
Chemical Abstract Service Registry ID: 7439-93-2
Group number: 1
Group name: Alkali metal
Period number: 2
Block: s-block
Standard state: solid at 298 K
Color: silvery white/grey
Classification: Metallic

You will not find lithium lying around in the open as lithium does not occur as the free metal. Lithium however is a component of nearly all igneous rocks and many natural brines with large deposits located in California and Nevada both in the good ole USA. You will find lithium in the rock forms spodumene, lepidolite, petalite, and amblygonite.

Lithium is extracted, one way, from the rock by heating the rock to 1100°C, mixing with sulphuric acid, H2SO4, and heating to 250°C. Then it is followed by extracting into water to create a lithium sulphate solution, Li2SO4. At this point then it can be used for various manufacturing purposes.

Lithium has high electrochemical potential and thus is used as a battery anode material in dry cells and storage batteries. In fact the energy of some lithium-based cells can be five times greater than an equivalent-sized lead-acid cell and three times greater than alkaline batteries. Lithium cells often have a starting voltage of 3.0 V. This means that batteries can be lighter in weight, have lower per-use costs, and have higher and more stable voltage profiles.

Here are some facts for lithium-ion battery cells:

The lightest of all metals
The greatest electrochemical potential
The largest energy density for weight.
The load characteristics are reasonably good in terms of discharge.
The high cell voltage of 3.6 volts allows battery pack designs with only one cell versus three.
It is a low maintenance battery.
No memory and no scheduled cycling is required to prolong the battery's life.
Lithium-ion cells cause little harm when disposed.
It is fragile and requires a protection circuit to maintain safe operation.
Cell temperature is monitored to prevent temperature extremes.
Capacity deterioration is noticeable after one year (whether the battery is in use or not).

Here are some facts for Lithium Polymer Battery Cells:

The lithium-polymer differentiates itself from the conventional battery in the type of electrolyte used (a plastic-like film that does not conduct electricity but allows ion exchange – electrically charged atoms or groups of atoms).
The polymer electrolyte replaces the traditional porous separator, which is soaked with electrolyte.
The dry polymer design offers simplifications with respect to fabrication, ruggedness, safety and thin-profile geometry.
Cell thickness measures as little as one millimeter (0.039 inches).
Can be formed and shaped in any way imagined.
Commercial lithium-polymer batteries are hybrid cells that contain gelled electrolyte to enhane conductivity.
Gelled electrolyte added to the lithium-ion-polymer replaces the porous separator. The gelled electrolyte is simply added to enhance ion conductivity.
Capacity is slightly less than that of the standard lithium-ion battery.
Lithium-ion-polymer finds its market niche in wafer-thin geometries, such as PDA batteries.
Improved safety – more resistant to overcharge; less chance for electrolyte leakage.