Battery Glossary
Primary Cell: An electrochemical device that is discharged only once and then discarded. Alkaline batteries are an example.
Secondary Cell: An electrochemical device that may be discharged and recharged a number of times. Li-Ion batteries are an example.
Battery Capacity: The ampere-hours available from battery.
Battery Float Voltage: A constant voltage applied to a battery to maintain the battery capacity.
Amp Hour or Ampere-Hour : A unit of measurement of a battery’s electrical storage capacity. Current multiplied by time in hours equals ampere-hours. One amp hour is equal to a current of one ampere flowing for one hour. Also, 1 amp hour is equal to 1,000 mAh
C : Used to signify a charge or discharge rate equal to the capacity of a battery divided by 1 hour. Thus C for a 1600 mAh battery would be 1.6 A, C/5 for the same battery would be 320 mA and C/10 would be 160 mA. Because C is dependent on the capacity of a battery the C rate for batteries of different capacities must also be different.
Cycle Life : For rechargeable batteries, the total number of charge/discharge cycles the cell can sustain before it capacity is significantly reduced. End of life is usually considered to be reached when the cell or battery delivers only 80% of rated ampere- hour capacity. The life of a rechargeable battery operating under normal conditions is generally between 500 to 800 charge-discharge cycles. The cycle of a battery is greatly influenced by the type depth of the cycle (deep or shallow) and the method of recharging. Improper charge cycle cutoff can greatly reduce the cycle life of a battery.
Energy Density :Ratio of cell energy to weight or volume (watt-hours per pound, or watt-hours per cubic inch).
Memory Effect : A phenomenon in which a cell, operated in successive cycles to less than full, depth of discharge, temporarily loses the remainder of its capacity at normal voltage levels (usually applies to Ni-Cd cells). Note, memory effect can be induced in NiCd cells even if the level of discharge is not the same during each cycle. Memory effect is reversible.
Self-discharge: A phenomenon that an active material is transformed into the discharge condition even in the state of open external current circuit is called ’ self-discharge’.
Battery FAQ In General
1. How are batteries rated? (What Are Volts and Amps?)
There are two ratings on every battery: volts and amp-hours (AH). The AH rating may also be given
as milliamp-hours (mAH), which are one-thousandth of an amp-hour (for example, 1AH is 1000mAH).
The voltage of the new battery should always match the voltage of your original unless the batteries
are different chemistries (NiMH and Li-Ion batteries have different voltage ratings, even if they’re for
the same laptop). Some Hi-Capacity batteries will have higher amp-hour ratings than the original
battery found in the device. This is indicative of a longer run-time (higher capacity) and will not cause
any incompatibilities.
2. How can batteries be connected?
Batteries may be connected in series. The positive terminal of the first battery is connected to the
negative terminal of the second battery; the positive terminal of the second is connected to the
negative of the third, and so on. The voltage of the assembled battery is the sum of the individual
batteries. The batteries are connected: + to - to + to - to + to -, etc. The capacity of the battery is
unchanged.
Batteries may also be connected in parallel. The positive terminal of the first battery is connected
to the positive terminal of the second battery, the positive terminal of the second is connected to
the positive of the third; the negative terminal of the first battery is connected to the negative
terminal of the second battery, the negative terminal of the second is connected to the negative of
the third and so on. The batteries are connected: + to + to + and - to - to -. In this configuration,
the capacity is the sum of the individual batteries and voltage is unchanged.
For example, (5) 6V 10AH batteries connected in series produces a battery array that is 30 Volts
and 10AH. Connecting the batteries in parallel produces a battery array that is 6 Volts and 50AH.
Ordinary auto batteries are designed in the same fashion. Six 2-volt cells are arranged in series to
produce a 12v battery. Many NiCad batteries are arranged in the same way
Note: When interconnecting batteries (cells), they must be identical in voltage and amp rating!
3. Do batteries self-discharge when not in use?
All batteries, regardless of their chemistry, self-discharge. The rate of self-discharge depends both
on the type of battery and the storage temperature the batteries are exposed to. There is very little
self-discharge in the solid electrolyte system, but it is very notable in the liquid electrolyte system.
It is also influenced by the surrounding temperature. Summer can have more influence over it than
winter .
In the case of primary battery, the rate of self discharged are followed below:
Manganese battery : 10%/year
Alkaline battery : 5%/year
Lithium battery : 1%/year
The self-discharge rates of second battery are higher than those of primary battery. Particularly, the
performances of second batteries are different depending on battery makers. It is because they form
artificial, chemical structure in order to make it possible to use the battery many times. With this
reason, there are differences of performance depending upon the battery makers although the variations
are not big.
Here are some examples based on second batteries.
Ni-MH cell : 5 ~ 10%/month
Ni-Cd cell : 25 ~ 30%/month
Li-ion battery : 2%/month
Lead-acid Battery :
Pb-Sb alloy group : 25 ~ 30%/month
Pb-Ca alloy group : 2%/month
4. What are the different types of rechargeable battery chemistries & technologies?
Batteries in portable consumer devices (laptops and notebooks, camcorders, cellular phones, etc.)
are principally made using either Nickel Cadmium (NiCad), Nickel Metal Hydride (NiMH) or Lithium
Ion (Li-Ion) technologies. Each type of rechargeable battery technology has its own unique
characteristics.
FAQ For Li-ion Battery
1. What is the difference between Lithium batteries and Lithium Ion batteries?
There are several important differences. The practical difference between Lithium batteries and Lithium-ion(Li-ion) batteries is that most Lithium batteries are not rechargeable but Li-ion batteries are rechargeable. From a chemical standpoint Lithium batteries use lithium in its pure metallic form. Li-ion batteries use lithium compounds which are much more stable than the elemental lithium used in lithium batteries. A lithium battery should never be recharged while lithium-ion batteries are designed to be recharged hundreds of times.
2. What are the advantages of Lithium Ion batteries compared to other rechargeable batteries?
Lithium-ion batteries have several advantages:
They have a higher energy density than most other types of rechargeables. This means that for their size or weight they can store more energy than other rechargeable batteries. They also operate at higher voltages than other rechargeables, typically about 3.7 volts for lithium-ion vs. 1.2 volts for NiMH or NiCd. This means a single cell can often be used rather than multiple NiMH or NiCd cells.
Lithium-ion batteries also have a lower self discharge rate than other types of rechargeable batteries. This means that once they are charged they will retain their charge for a longer time than other types of rechargeable batteries. NiMH and NiCd batteries can lose anywhere from 1-5% of their charge per day, (depending on the storage temperature) even if they are not installed in a device. Lithium-ion batteries will retain most of their charge even after months of storage.
So in summary; lithium-ion batteries can be smaller or lighter, have a higher voltage and hold a charge much longer than other types of batteries.
| Items |
Li-ion |
Ni-MH |
Lead-acid |
| Cycle life (cycles) |
500 |
400 |
300 |
| Energy efficiency (C discharge/C charge) |
99% |
70% |
75% |
| Weight comparison for the same capacity |
1 |
2 |
4 |
| Size comparison for the same capacity |
1 |
1.8 |
3.5 |
| Reliability |
High |
Low |
High |
3. What are the disadvantages of Lithium Ion batteries compared with other rechargeable batteries?
Lithium-ion batteries are more expensive than similar capacity NiMH or NiCd batteries. This is because they are much more complex to manufacture. Li-ion batteries actually include special circuitry to protect the battery from damage due to overcharging or undercharging. They are also more expensive because they are manufactured in much smaller numbers than NiMH or NiCd batteries. Li-ion batteries are becoming less expensive and over time we should see their price decrease significantly.
Lithium ion batteries are not available in standard cells sizes (AA, C and D) like NiMH and NiCd batteries.
Lithium-ion batteries also require sophisticated chargers that can carefully monitor the charge process. And because of their different shapes and sizes each type of Li-ion battery requires a charger designed to accommodate its particular size. This means lithium ion battery chargers are more expensive and more difficult to find than NiMH and NiCd battery chargers.
4. What is the best way to store Lithium Ion batteries?
Lithium-ion batteries can hold a charge for many months. It is best to store a lithium-ion battery with a partial or full charge. Occasionally, a lithium-ion battery with a very low charge is stored for a long period of time (many months) and its voltage slowly drops to below the level at which its built in safety mechanism allows it to be charged again. If the battery is going to be stored for several months it’s a good idea to take it out and recharge it after a few months. Better yet would be to actually use the battery every few months and then leave it partially or fully charged.
5. How should I dispose of Lithium Ion batteries?
Lithium ion batteries, like all rechargeable batteries are recyclable and should be recycled. They should never be incinerated since they might explode. Most places that sell rechargeable batteries will also accept them back for recycling.
FAQ For Lithium Iron Phosphate Battery
1. What is a Lithium iron phosphate battery?
The lithium iron phosphate (LiFePO4) battery is a type of rechargeable battery, specifically a lithium ion battery, which uses LiFePO4 as a cathode material.
2. What are the characteristics of LiFePO4 battery compared with other Lithium base batteries ?
There are three types of lithium ion cells based on different cathode materials. They are lithium cobalt oxide, lithium manganese oxide and lithium iron phosphate types. Although lithium cobalt oxide cell has the advantage of high energy density, it suffers from safety concerns. Lithium manganese oxide cell has been evaluated for the application on high rate due to the better safety characteristics. However, its high temperature performance is the major drawback.
While Lithium iron phosphate cell has the best safety characteristics, long cycle life (up to 2000 cycles) and good availability. It has higher discharge current, but has lower voltage and energy density than normal Li-ion cells. It is the safest and most suitable for high output usage. It is also the best for storage battery usage. It is not necessary to use the equalizer and the protecting PC Board module.
Comparison Data Among Various Lithium Base Batteries:
| Battery |
LiFePO4 |
LiCoO2 |
LiMn2O4 |
Li(NiCo)O2 |
| Safety |
Safest |
Not Stable |
Acceptable |
Not Stable |
| Environmental concern |
Most Enviro-friendly |
Very Dangerous |
|
Very Dangerous |
| Cycle life |
Best/Excellent |
Acceptable |
Acceptable |
Acceptable |
| Power/Weight Density |
Acceptable |
Good |
Acceptable |
Best |
| Long Term Cost |
Most Economic/Excellent |
High |
Acceptable |
High |
| Temperature Range |
Excellent (-20C to 70C) |
Decay beyond (-20C to 55C) |
Decay extremely fast over 50 C |
-20C to 55C
|
In summary, the characterics of lithium iron phosphate (LiFePO4) are as follows:
A) . The safest and the most nvironmental friendly
The Lithium Iron Phosphate Battery has been proven as the most environmental friendly battery. The primary concern with Li-Ion batteries is safety. Overcharging and overheating can cause fire and explosions. The exception to this is the LiFePO4 battery.
B). Fast "forced" charging
Because an overvoltage can be applied to the LiFePO4 battery it can be charged by only one step of CC to reach 95%SOC or be charged by CC+CV to get 100%SOC. This is similar to the way lead acid batteries are safely force charged.
C). Large overcharge tolerance and safer performance
A LiFePO4 battery can be safely overcharged up to 30V without protection circuit board. It is therefore suitable for large capacity and high power applications. From the viewpoint of large overcharge tolerance and safety performance, a LiFePO4 battery is similar to a lead-acid battery.
D). Highe energy density
the lithium iron phosphate (LiFePO4) cell is a non-aqueous system, having 3.2V as its nominal voltage during discharge. Its specific capacity is more than 145Ah/kg. Therefore, the gravimetric energy density of LiFePO4 battery is 130Wh/kg,
E). Simplified battery management system and battery charger
Large overcharge tolerance and self-balance characteristic of LiFePO4 battery can simplify the battery protection and balance circuit boards, lowering their cost.
F). Longer cycle life
In comparison with LiCoO2 battery which has a cycle life of 400 cycles, LiFePO4 battery extends its cycle life up to 2000 cycles.
G). High temperature performance
It is detrimental to have a LiCoO2 battery working at elevated temperature, such as 60°C. However, a LiFePO4 battery runs better at elevated temperature, offering 10% more capacity, due to higher lithium ionic conductivity.
H). What are the main applications of the lithium iron phosphate (LiFePO4)?
Due to the characteristics of lithium iron phosphate (LiFePO4), it is very suitable for high discharge rate occasions such as EV (including e-bike, electric scooter, and electric car), power tools (for example, electric drill, electric motor saw, cropper), UPS and emergency lighting, solar energy system. According to different applications, the design of battery pack can be modified to provide the best solution to satisfy the customer’ s needs.
FAQ For Solar Light
1. What are the advantages of outdoor solar lighting?
Outdoor solar lightings, with low voltage lights, are a landscape lighting option. They require no electrical wiring. They are powered by DC electricity generated from sunshine and can easily be relocated should you redesign your landscape. Solar garden lights have built-in photo sensors so they automatically turn off during the day and turn on at night. Best of all, light from solar garden lamps doesn’t require the burning of fossil fuels and the generation of carbon dioxide (CO2) and pollutants associated with the generation of electricity by a utility. Solar lights also score high marks for their use of renewable energy and little or no emission of pollutants
2. What does the solar light contain?
The two basic components of a solar powered light include light source. This can be LED lamps and a photocell or photovoltaic (PV) cell to harness the sun’s energy and charge the batteries integrated into light fixtures.
3. What are the features of solar outdoor lighting?
With the advent of technology, the latest solar outdoor lightings come with a self programmed feature. There is no reason to worry if one light fails, as the other light is not affected by this failure. For effective working of solar powered outdoor lightings, the impact rests on charging of batteries and night time usage. During the day, the PV cells should have good exposure to the sun’s radiation and should not be placed in an uncluttered location for optimal charging of the batteries. This can be effectively implemented by placing the lights at appropriate positions.
4. What are the types of outdoor solar lighting available?
outdoor solar lighting s come in various shapes and styles, some of the most sought types include outdoor solar copper lighting, pathway solar lights, solar lighted planters, task solar Lights, tiered solar light, etc.,
5. How to choose solar outdoor lighting?
There are several factors involved when you choose to go for solar powered lighting. Effective planning and correct choice adds beauty to your home. The type of solar lighting you choose depends on the following factors, such as cost involved and landscaping. You also need to see if the solar outdoor lighting you have chosen suits your landscape by taking into account the following characteristics - the layout of the location (garden or backyard ), colors in the garden , statues or figurines at your garden, and the total area where solar powered lightings have to be placed. At commercial establishments you may consider using a customized outdoor solar lighting system such a solar outdoor flood lighting to provide bright light.
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