Though the silicon nanoparticle batteries 

June 10 [Mon], 2013, 11:04
Researchers at USC have developed a new lithium-ion battery design that uses porous silicon nanoparticles in place of the AS07A71 compatibletraditional graphite anodes to provide superior performance.

The new batteries — which could be used in anything from cellphones to hybrid cars — hold three times as much energy as comparable graphite-based designs and recharge within 10 minutes. The design, currently under a provisional patent, could be commercially available within two to three years.

“It’s an exciting research. It opens the door for the design of the next generation lithium-ion batteries,” said Chongwu Zhou, professor at the USC Viterbi School of Engineering, who led the team that developed the battery.

Zhou worked with USC graduate students Mingyuan Ge, Jiepeng Rong, Xin Fang and Anyi Zhang, as well as Yunhao Lu of Zhejiang University in China. Their research was published in Nano Research in January.

Researchers have long attempted to use silicon, which is cheap and has a high potential capacity, in battery anodes. (Anodes are where current flows into a battery, while cathodes are where current flows out.)

The problem has been that previous silicon anode designs, which were basically tiny plates of the material, broke down from repeated swelling and shrinking during charging/discharging cycles and quickly became useless.

Last year, Zhou’s team experimented with porous silicon nanowires that are less than 100 nanometers in diameter and just a few microns long.

The tiny pores on the nanowires allowed the silicon to expand and contract without breaking while simultaneously increasing the surface area, which in turn allows lithium ions to diffuse in and out of the battery more quickly, improving performance.

Though the batteries functioned well, the nanowires are difficult to manufacture en masse. To solve the problem, Zhou’s team took commercially available nanoparticles — tiny silicon spheres — and etched them with the same pores as the nanowires. The particles function similarly and can be made in any quantity desired.

Though the silicon nanoparticle batteries currently last for just 200 recharge cycles (compared to an average of 500 for graphite-based designs), the team’s older silicon nanowire-based design lasted for up to 2,000 cycles, which was reported in Nano Letters last April.

Further development of the nanoparticle design should boost the battery’s life span, Zhou said.

“The easy method we use may generate real impact on AS07B71 compatibleapplications in the near future,” Zhou said.

Future research by the group will focus on finding a new cathode material with a high capacity that will pair well with the porous silicon nanowires and/or porous silicon nanoparticles to create a completely redesigned battery.

Welding the cells is the only reliable way to get dependable connection 

April 22 [Mon], 2013, 16:54
Batteries for power tools and other industrial devices can often be repaired by replacing one or all cells. Finding a NiCd and NiMH cell is relatively easy; locating the correct Li-ion cell can be more difficult. Naked Li-ion cells are not readily available off the shelf and a reputable battery manufacturer may only sell to HSTNN-DB73 laptop battery certified pack assemblers. Incorrect use or lack of an protection circuit could cause stress and disintegration of the replaced cell. When repairing a Li-ion pack make certain that each cell is properly connected to a protection circuit. Read about Safety Concerns and Protection Circuits.

If a relatively new pack has only one defective cell, you may replace only the affected cell. On an aged battery, it’s best to replace all cells. Adding a new cell with full capacity in between neighboring cells that have faded would cause a cell mismatch. Matching the replacement cell with one of a lower rating may work but this fix is often of short duration. Always replace with the same chemistry cell.

A well-matched battery pack means that all cells have similar capacities. An anomaly can be drawn with a chain in which the weakest link determines the performance of the battery. Read more about Can Batteries Be Restored?.

When replacing all cells, the rating is less important as long as the differences are not too large for the charger to handle. Cells with higher Ah will simply take a bit longer to charge. The state-of-charge of all cells being charged for the first time should have a similar charge level, and the open-circuit voltages should be within 10 percent of each other

Many visitors of BatteryUniversity.com ask if NiCd can be replaced with NiMH? Theoretically, this should be possible but charging may be an issue. NiMH uses a more defined charge algorithm than NiCd. A modern NiMH 497694-001 laptop battery charger can charge both NiMH and NiCd; the old NiCd charger could overcharge NiMH by not properly detecting full charge state and applying a trickle charge that is too high.

Welding the cells is the only reliable way to get dependable connection. Limit the heat transfer to the cells during welding to prevent excess heat buildup.

Some laptop manufacturers disallow aftermarket batteries  

April 22 [Mon], 2013, 16:47
In the search for low-cost batteries, consumers may inadvertently purchase counterfeit batteries that are unsafe. The label appears bona fide and the buyer cannot distinguish between an original and a forged product. Cell phone manufacturers are concerned about these products flooding the market and 593550-001 laptop battery advise customers to use approved brands; defiance could void the warranty. Manufacturers do not object to third-party suppliers as long as the aftermarket batteries are well built, safe and approved by a safety agency.

Caution also applies to purchasing counterfeit chargers. Some aftermarket chargers do not terminate the battery correctly and rely on the battery’s internal protection circuit to cut off the charge when the battery is full.

The need for redundancy in charging is important because a bona fide battery could have a malfunctioning protection circuit that was damaged by a static charge or other cause. If, for example, the maker of the counterfeit battery relies on the charger to terminate the charge, and the manufacturer of the charger Pavilion probook 4710s laptop battery depends fully on the battery’s protection circuit, a combination exists that can have serious consequences.

Some laptop manufacturers disallow aftermarket batteries by digitally locking the pack with a tamperproof security code. This is done in part for safety reasons; the potential damage resulting from a faulty laptop battery is many times greater than that of a cell phone.

Batteries are now ubiquitous 

March 11 [Mon], 2013, 14:42
The first test of any combination of substances that comes out of the Materials Project, or anywhere else, will be to beat the most successful electricity-storage device to emerge over the past 20 years: the lithium-ionbright 636631-001. Such batteries are now ubiquitous.

Most famously, they power many of the electric and hybrid-electric cars that are starting to appear on the roads. More infamously, they have a tendency to overheat and burn. Two recent fires on board Boeing’s new 787 Dreamliners may have been caused by such batteries or their control systems. Improving on lithium-ion would be a feather in the cap of any laboratory.

George Crabtree, JCESR’s newly appointed director, thinks such improvements will be needed soon. He reckons that most of the gains in performance to be had from lithium-ion batteries have already been achieved, making the batteries ripe for replacement. Jeff Chamberlain, his deputy, is more bullish about the existing technology. He says it may still be possible to double the amount of energy a lithium-ionbright HSTNN-OB80of given weight can store, and also reduce its cost by 30-40%.

This illustrates the uncertainty about whether lithium-ion technology, if pushed to its limits, can make electric vehicles truly competitive with those run by internal-combustion engines, let alone better. McKinsey, a business consultancy, reckons that lithium-ion batteries might be competitive by 2020 but, as the chart below shows, there is still a lot of work to do. Moreover, pretenders to lithium-ion’s throne are already emerging.

There are all sorts of new type batteries being worked on 

March 11 [Mon], 2013, 14:41
On the commercial market, lithium ion batteries are generally ones small enough to fit into cellphones. But to power bigger items -- from a Prius to a 787 -- they get grouped together, increasing the juice they storebright Pavilion 13 battery and provide. That also increases the safety risk, experts say. The lithium ion battery that caught fire in a Boeing 787 weighed 63 pounds and was 19 inches long.

"You can't get around the fundamental thing is that lithium ion batteries are stuffed full of flammable liquid," Whitacre said.

Even one-in-a-million problems with lithium ion batteries can result in many fires because there are billions of them in use now, with dozens sometimes stacked together in a single device.

Experts say lithium ion batteries are more dangerous because their electrolyte, the liquid that allows ions to move between electrodes in the battery, is more flammable than the substance in older type batteries. Those older types include the lead-acid batteries in most cars and the nickel cadmium batteries that are often in video equipment and power tools.
Still, MIT materials science and engineering professor Gerbrand Ceder and others said the safety problems can be fixed.
Change doesn't come often in the battery field.

"The big advances in battery technology happen rarely. It's been more than 200 years and we have maybe five different successful rechargeable batteries," said George Blomgren, a former senior technology researcher at Eveready and now a private battery consultant. "It's frustrating."

Alessandro Volta -- for whom the volt is named -- invented the first useful battery in 1800. That was long before other breakthrough inventions like the internal combustion engine, telephone, car, airplane, transistor, computer and Internet. But all of those developments have seemed to evolve faster than the simple battery.

The lead-acid car battery "has been around for 150 years more or less," Whitacre said. "This is a remarkable testament to first how robust that chemistry is and how difficult change is."

Battery experts are split over what's next. Some think the lithium ion battery can be tinkered with to get major efficiency and storage improvements. Amatucci said he thinks we can get two to three times more energy out of future lithium ion batteries, while others said minor chemical changes can do even more.

But just as many engineers say the lithium ion battery has run its course.
"With the materials in the current lithium ion battery, we are definitely plateaued," Blomgren said. "We're waiting for something to come along that really does the job."
There are all sorts of new type batteries being worked on: lithium-air, lithium-sulfur, magnesium, sodium-ion.

"Right now it's a horse race," Blomgren said. "There's deficiencies in every technology that's out there. Each one of them requires a major solution."
One of the nation's best hopes bright 487296-001for a breakthrough, said Battaglia, is John Goodenough, the man responsible for the 1979 breakthrough that led the first commercial lithium ion battery in 1991. He will receive the National Medal of Science at the White House next month.
Goodenough is 90.

"I'm working on it," Goodenough, an engineering professor at the University of Texas at Austin, said Tuesday. "I'm optimistic in a sense that I'm willing to keep working on it. I think we can do some interesting things."

Other zinc-air batteries use zinc pellets 

January 07 [Mon], 2013, 12:39
Since the invention in 1839 by Sir William Grove, the fuel cell remained a scientific oddity. It was only in the 1950s that this power generator was used for the first time as part of US space and military programs. In the 1980s, the fuel 11.1v 5200mah 9cells 487296-001cell had another rebirth when scientists and stock promoters envisioned a world powered by a clean power source fed by an inexhaustible fuel, hydrogen.

They forecasted cars running by fuel cells and households deriving electrical power from back-yard fuel cell units. In the late 1990s, fuel cell technology gained hype status and many saw this power source as the gateway to the future. High manufacturing costs and short service life were in the way to make this dream a reality.

The fuel cell uses hydrogen and oxygen as fuel. Combining the two gases generates electricity and water. There is not combustion and no pollution. The byproduct is pure water. The system runs so clean that Ballard, a developer of fuel cell stacks, offered the guests tea from the hot water produced by the fuel cell. The absence of exhaust fumes enables running a fuel cell in an enclosed room, such as an office of living room. The theoretical energy output of the fuel cell is high, but over half is lost in heat.

During the past years, portable versions of the fuel cells have emerged. The most promising miniature fuel cell is the direct methanol fuel cell. Read more about Fuel Cell Technology. DMCF is inexpensive, convenient, does not require pressurized hydrogen gas and provides a reasonably good electrochemical performance. Current systems produce 900Wh of power and offer an energy density of 102Wh/l, but this volumetric dimension is still large compared to a lithium-ion battery. Charging consists by replacing the cartridge on the fly. This provides a continued source of energy, similar to fueling a car. Figure 1 shows a miniature Toshiba fuel cell, also known as micro fuel cell; Figure 2 demonstrates refueling with methanol that is 99.5 percent pure.
9
Zinc-air batteries generate electrical power by an oxidation process of zinc and oxygen from the air. The cell can produce 1.65V, however, 1.4V and lower achieves a longer lifetime. To activate the battery, the user removes a sealing tab that enables airflow and the battery reaches full operating voltage within five seconds. Once turned on, the battery cannot be reverted back to the standby mode, the chemicals dry out, and the battery has a short shelf life. Adding a tape to stop airflow slows the degeneration.

Zinc-air batteries have similarities to the proton exchange membrane fuel cell (PEMFC) in that they use oxygen in the air as fuel for the positive electrode. Read about the fuel cell. Air can, to a certain extent, control the rate of the reaction. Zinc-air is considered a primary battery, however, there are recharging versions for high-power applications. Recharging occurs by replacing the spent zinc electrodes, which can be in the form of a zinc electrolyte paste.
Other zinc-air batteries use zinc pellets.

At 300–400Wh/kg, zinc-air has a high specific energy but the specific power is low. Manufacturing cost is low and in a sealed state, zinc-air has a two percent self-discharge per year. Zinc-air is sensitive to extreme 11.1v 5200mah 9cells 636631-001 temperatures and high humidity. Pollution also affects performance, and high ambient carbon dioxide reduces the performance by increasing the internal resistance. Typical applications include hearing aids; high-power versions operate remote railway signaling and safety lamps at construction sites.

Lithium-ion requires a protection circuit to provide safe operations 

November 19 [Mon], 2012, 11:15
Nickel-cadmium batteries continue to power a large percentage of professional cameras. This battery provided reliable service and performs well at low temperature. nickel-cadmium is one of the most enduring batteries in terms Nickel-cadmium batteries continue to power a large percentage of professional cameras. This high quality Pavilion Mini 1000 battery provided reliable service and performs well at low temperature. nickel-cadmium is one of the most enduring batteries in terms of service life but has only moderate energy density and needs a periodic full discharge.

The need for longer runtimes is causing a switch to nickel-metal-hydride. This battery offers up to 50% more energy than nickel-cadmium. However, the high current spikes drawn by digital cameras have a negative affect and the nickel-metal-hydride battery suffers from short service life.

There is a trend towards lithium-ion. Among rechargeables, this chemistry has the highest energy density and is lightweight. A steep price tag and the inability to provide high currents are negatives.

The 18650 cylindrical lithium-ion cell offers the most economical power source. "18" defines the cell's diameter in millimeters and "650" the length. No other lithium-ion cell, including prismatic or polymer types, offers a similar low cost-per-watt ratio.

Over the years, several cell versions of 18650 cells with different Ah ratings have emerged, ranging from 1.8Ah to well above 2Ah. The cells with moderate capacities offer better temperature performance, enable higher currents and provide a longer service life than the souped up versions.

The typical 18650 for industrial use is rated at 2Ah at 3.60 volts. Four cells are connected in series to obtain the roughly 15 volts needed for the cameras. Paralleling the cells increases the current handling by about 2A per cell. Three cells in parallel would provide about 6A of continuous power. Four cells in series and three in parallel is a practical limit for the 18650 system.

Lithium-ion requires a protection circuit to provide safe operations under all circumstances. Each cell in series is protected against voltage peaks and dips. In addition, the protection circuit limits each cell to a current about 2A. Even if paralleled, the current of a lithium-ion pack is not high enough to drive digital cameras requiring 10 to 15A peak current. Tests conducted at Cadex Electronics have shown that the 18650 allows short current peaks above the 2A/cell limit. This would allow the use of lithium-ion on digital cameras, provided the current bursts are limited to only a few seconds.of service life but has only moderate energy density and needs a periodic full discharge.

The need for longer runtimes is causing a switch to nickel-metal-hydride. This battery offers up to 50% more energy than nickel-cadmium. However, the high current spikes drawn by digital cameras have a negative affect and the nickel-metal-hydride battery suffers from short service life.

There is a trend towards lithium-ion. Among rechargeables, this chemistry has the highest energy density and is lightweight. A steep price tag and the inability to provide high currents are negatives.

The 18650 cylindrical lithium-ion cell offers the most economical power source. "18" defines the cell's diameter in millimeters and "650" the length. No other lithium-ion cell, including prismatic or polymer types, offers a similar low cost-per-watt ratio.

Over the years, several cell versions of 18650 cells with different Ah ratings have emerged, ranging from 1.8Ah to well above 2Ah. The cells with moderate capacities offer better temperature performance, enable higher currents and provide a longer service life than the souped up versions.

The typical 18650 for industrial use is rated at 2Ah at 3.60 volts. Four cells are connected in series to obtain the roughly 15 volts needed for the cameras. Paralleling the cells increases the current handling by about 2A per cell. Three cells in parallel would provide about 6A of continuous power. Four cells in series and three in parallel is a practical limit for the 18650 system.

Lithium-ion requires a protection circuit to provide safe operations under all circumstances. Each cell in series is protected against voltage peaks and dips. In addition, the protection circuit limits each cell to a current about 2A. Even if paralleled, the current of a lithium-ion pack is not high enough to drive digital cameras9cells 513775-001 requiring 10 to 15A peak current.

Tests conducted at Cadex Electronics have shown that the 18650 allows short current peaks above the 2A/cell limit. This would allow the use of lithium-ion on digital cameras, provided the current bursts are limited to only a few seconds.

A full charge and discharge is necessary 

November 19 [Mon], 2012, 11:11
Most laptop batteries are 'smart'; meaning that they know how much energy is left. Such a feature has definite benefits but the readings are often inaccurate. A laptop may indicate 30 minutes of remaining runtime when suddenly t11.1v 5200mah 9cells 537626-001he screen goes dark. Here is the reason why:

With use and time, a tracking error occurs between the chemical battery and the digital sensing circuit. The most ideal use of the 'smart' battery, as far as fuel-gauge accuracy is concerned, is a full charge followed by a full discharge at a constant current. In such a case, the tracking error would be less than 1% per cycle. In real life, however, a battery may be discharged for only a few minutes and the load may vary widely. Long storage also contributes to errors because the circuit cannot accurately compensate for self-discharge. Eventually, the true capacity of the battery no longer synchronizes with the fuel gauge and a full charge and deliberate full discharge will be needed to 're-learn' or calibrate the battery.

There are no standards to tell what constitutes a fully charged and fully discharged battery. Lithium-ion packs are considered fully charged when the limiting voltage (4.20V/cell) is reached and the saturation current has decreased to 3% of the nominal value (50mA on a 1700mAh cell). Some chargers use 5% and 8% as 'ready' criteria.) A full discharge occurs when the cell reaches 3V/cell or lower. At this voltage level, the battery has a remaining capacity of 3 to 10%. Modern batteries adjust to a lower cut-off voltage on high load currents and include temperature compensation.

To calibrate a battery, a full charge and discharge is necessary. One without the other does not constitute a calibration. A problem arises if the battery is recharged after a brief use without providing the opportunity of a full discharge. A forced discharge to "Low Battery" may be needed from time to time.

What happens if no battery calibration is done? Can such a battery be used in confidence? Most 'smart' battery chargers obey the dictates of the chemical cells rather than that of the electronic circuit. In this case, the replacement 607762-001 will fully charge regardless of the fuel gauge setting and function normally but the digital readout will become increasingly more inaccurate. If not corrected, the fuel gauge simply becomes a nuisance.

Cadex Electronics manufactures 'smart' chargers and battery analyzers that are capable of calibrating a 'smart' battery.

Rigorous use of code review and unit testing measures  

September 17 [Mon], 2012, 12:07
There are two different approaches to security in computing. One focuses mainly on external threats, and generally treats the computer system itself as a trusted system. This philosophy is discussed in the computer insecurity article.

The other, discussed in this article, regards the computer system itself as largely an untrusted system, and redesigns it torn873 593572-001 make it more secure in a number of ways.

This technique enforces privilege separation, where an entity has only the privileges that are needed for its function. That way, even if an attacker has subverted one part of the system, fine-grained security ensures that it is just as difficult for them to subvert the rest.

Furthermore, by breaking the system up into smaller components, the complexity of individual components is reduced, opening up the possibility of using techniques such as automated theorem proving to prove the correctness of crucial software subsystems. Where formal correctness proofs are not possible, rigorous use of code review and unit testing measures can be used to try to make modules as secure as possible.

The design should use "defense in depth", where more than one subsystem needs to be compromised to compromise the security of the system and the information it holds. Subsystems should default to secure settings, and wherever possible should be designed to "fail secure" rather than "fail insecure" (see fail safe for the equivalent in safety engineering). Ideally, a secure system should require a deliberate, conscious, knowledgeable and free decision on the part of legitimate authorities in order to make it insecure. What constitutes such a decision and what authorities are legitimate is battery for F287H obviously controversial.

In addition, security should not be an all-or-nothing issue. The designers and operators of systems should assume that security breaches are inevitable in the long term. Full audit trails should be kept of system activity, so that when a security breach occurs, the mechanism and extent of the breach can be determined. Storing audit trails remotely, where they can only be appended to, can keep intruders from covering their tracks. Finally, full disclosure helps to ensure that when bugs are found the "window of vulnerability" is kept as short as possible.

Many organizations duplicate and distribute copies or parts of databases to network servers at a variety of sites 

September 17 [Mon], 2012, 12:03
A database is an integrated collection of computer data, organized and stored in a manner that facilitates easy retrieval. Two primary goals of the database are to minimize data redundancy and to achieve data independence. Data redundancy is the duplication of data that is, the same data is stored in multiple files. Data independence is the ability to make changes in data structure without making changes to the programs that process the data. Data independence is accomplished by the placing ofhigh quality 482962-001 data specifications in tables and dictionaries that are physically separate from the programs.

Characteristics of Database:

It is a centralized and integrated shared data file which consists of all data used by a company.

It is organized and structured in a different manner than the conventional sequential file organization.
Its organization permits access to any or all data quantities by all applications with equal ease.
Its organization is such that duplication of data is minimized if not eliminated entirely.

It emphasizes the independence of programs and data. It involves the concept of separating data definition from the applications programs and including it as part of the database.

It provides for the definition of logical relationships which exist between various records in the database.

It is stored on a direct-access storage device.

Types of Databases:

Continuing developments in information technology and its business applications have resulted in the evolution of several major types of databases. There are six major conceptual categories of databases that may be found in computer using organizations.

Operational Databases: these databases store detailed data needed to support the operations of the entire organization. They are also called subject area databases (SASD), transaction databases, and production databases. Examples are a customer database, personnel database. inventory database, and other databases containing data generated by business operations.

Analytical Databases: these databases store data and information extracted from selected operational and external databases. They consist of summarized data and information most needed by an organization's managers and other end users. Analytical databases also called management databases, or information databases. They may also called multidimensional databases, since they frequently use a multidimensional database structure to organize data.

Database Warehouse: a data warehouse store data from current and previous years that has been extracted from the various operational databases of an organization. It is a central source of data that has been screened, edited, standardized, and integrated so it can be used for a variety of forms of business analysis, market research, and decision support. Data warehouse may be subdivided into data marts, which hold specific subsets of data from the warehouse. A major use of data warehouse database is data mining. In data mining the data in a data warehouse are processed to identify key factors and trends in historical patterns of business activity. This can be used to help managers make decisions about strategic change in business operations to gain competitive advantages in the marketplace.

Distributed Databases: Many organizations duplicate and distribute copies or parts of databases to network servers at a variety of sites. These distributed databases can reside on network servers on the World Wide Web, on corporate intranets or extranets, or on other company networks. Distributed databases may be copies of operational or analytical databases, hypermedia or discussion databases, or any other type of database.

End User Database: these databases consist of a variety of data files developed by end users at their workstations. For example, users may have their own electronic copies of documents they download from the World Wide Web, generate with word processing packages, or receive by electronic mail. Or they may have11.1v 5200mah 9cells 493976-001 their own data files generated from using spreadsheet and DBMS packages.

External Databases: access to a wealth of information from external databases is available for a fee from commercial online service, and with or without charge from many sources on the Internet, especially the World Wide Web. Web sites provide an endless variety of hyperlinked pages of multimedia documents in hypermedia databases for accessing. Data is available in the form of statistics on economic and demographic activity from statistical data banks. Or users can view or download abstracts or complete copies of hundreds of newspapers, magazines, newsletters, research papers, and other published material and other periodicals from bibliographic and full text databases.