Showing posts with label culture. Show all posts
Showing posts with label culture. Show all posts

Monday, May 3, 2010

Lithium battery explosion reason and prevention

According to the U.S. well-known science writer Marshall Brain series of articles in the lithium batteries introduction, the vast majority of lithium battery explosion caused by a short circuit, and the specific reasons, including charging overvoltage / over-current use of aging.



Lithium laptop battery manufacturing process, because the manufacturing process itself flawed, it is easy to be insulated in this between the two poles, leaving metal dust, copper foil, aluminum foil pieces. The angle is expected in the battery than the fever (more common in long-term use or charging), the like boiling water in a grain of rice, as in the electrolyte to make random thermal motion. If you happen to have the battery positive and negative particles or debris near the middle of the diaphragm level, it could create a divide perforation, triggering micro-short circuit. As the batteries are flammable organic electrolytes, micro-short-circuit may cause an explosion, burning and other accidents, generally have the following three cases:



1. Sparks ignited the electrolyte, and thus bring disaster to come into contact with plastic body and flammable, resulting in fire;



2. Was experiencing an increase of temperature caused by the battery, the discount laptop battery inside the space is small, perhaps because of increased pressure to explode;



3. Batteries slower rise in temperature, the battery case to melt gradually, so that corrosive electrolyte leakage.



Lithium Dell Inspiron e1505 Battery safety problems can not stop now, because then the advanced manufacturing technology, will inevitably lead to planting the seeds in the electrolyte "missile." Should be noted that the formal sector of lithium battery production and sales have strict norms of acceptable quality lithium batteries, the number and size of debris have been controlled within a small, very low risk of perforation of diaphragm; batteries outside the Shell also used flame-retardant material, is not prone to fire.



The explosion-proof lithium battery of measures



Lithium Dell Inspiron 6000 Battery safety problems, the battery manufacturer, of course well aware, then what they used explosion-proof measures? Li-ion batteries for notebook computers, for example, its working principle is: Lithium batteries near full charge and discharge almost drained when the voltage drop, the control circuit detects this situation, notify the protection circuit cut off power supply to prevent overcharge or excessive discharge, so as not to shorten battery life.



The current notebook lithium batteries possess a more complete multi-level protection mechanism, even in the power charger, notebook computers unusual circumstances, the Dell Inspiron 1300 battery laptop can also be converted to automatic protection status, is generally not an explosion. But once the control circuit and protection circuit of the ability to work reduced hours, the battery on the verge of "dangerous" the. Mobile phones and other electronic products, lithium battery charge and discharge protection mechanisms, similar to this.



Do not need it "at arm's length"



In recent years, lithium-ion electronic products explosions often found newspapers, aroused a lot of consumer panic, some people for their own mobile phones, MP3 charging often "at arm's length"; also because of fear, simply a long-term will be cast aside Dell laptop battery, cause scrap. However, survey results, the majority of lithium battery explosions are the result of the user pay attention to safety tips, such as unauthorized modification, use of non-matching charger, the A1175 A1079 battery placed in extreme environments such as making.



Should be pointed out that the lithium technology as a kind of after 30 years of study, has successfully commercialized the mature technology, its safety is guaranteed. Regular brands of lithium batteries at the factory will have been numerous Road test procedure after they are sold as well as information feedback mechanism in order to recall the product in question in time.



United States Transportation Security Administration (TSA) is given following the recommendations of the safe use of lithium batteries:



1. Using the original charger: Li-ion battery charging time is the high period of bombing. Than the original VGP-BPS5 VGP-BPS2C battery charger is compatible with the battery charger to ensure better security.



2. Use of a reliable battery: try to buy original Sony laptop battery, not to save money to buy "second-hand goods", such batteries may be through maintenance, and reliable than original batteries.



3. Do not place the Latitude D620 battery extreme environments: high temperature, collisions, etc. are all important causes of battery explosion, as far as possible so that the battery is in a stable environment, away from the high-temperature areas.



4. Do not attempt to modify: the phone is a sophisticated communications equipment, in the design, manufacturers will have on its security, strictly textual research. After modification, the battery may be at not taking into account the environment before, an increase of security risks.


Via Batterytalk.info

Thursday, March 25, 2010

The battery life and aging

The battery life and aging



Rechargeable laptop battery have become an essential part of portable electronic devices. The following information will help you understand better how the battery performs.



There are three common types of rechargeable Dell XPS M140 Battery in portable electronic devices in use today: Nickel-cadmium (Ni-Cd), nickel-metal hydride (Ni-MH), Lithium Ion (Li-Ion). Most laptop batteries are lithium-ion batteries, so allow me some battery life of lithium-ion and aging.


Battery life depends on product configuration, product model, applications loaded on the product, power management settings, used the product and product features by the customer. as with all batteries, maximum capacity of the battery will decrease with time or use.



all batteries gradually lose their ability to hold a charge. The Dell XPS M1330 Battery life is the number of charge cycles and food materials before the battery can no longer hold a useful amount of cargo.



This loss in capacity (aging) is irreversible and can not be restored. Gradually, less and less active material is in each electrochemical cell are available to store a charge. Therefore, the battery provides less time for the power of the computer useful.



Lithium-ion (Li-ion) Dell XPS M1530 Battery usually have a lifespan of 300 to 500 cycles. With moderate use, Li-ion batteries can be expected to deliver approximately 80% of its original capacity after 300 cycles or about one year, see the use (chart).



Note: The above table shows the 80% of original Dell Latitude D820 Battery capacity after 300 cycles at an operating temperature between 77 ° C and 104 ° F (25 ° C and 40 ° C). Higher temperatures may be operating at 70% or more of the loss of function, the same number of cycles.

Wednesday, March 3, 2010

The temperature affection for different battery


Nickel-metal hydrides are less tolerant than nickel-cadmium in terms of the charge at low or high temperatures.

Nickel-metal-hydride can not load quickly at temperatures below 10 ° C, nor can they load slowly below 0 ° C. Some chargers are designed so that they Ladekoeffizienten and the ambient temperature change. Price considerations are not allowed to provide Apple PowerBook G4 12 inch Battery battery chargers for consumer electronics with temperature sensors.



At higher temperatures, the charge acceptance of nickel-based Apple PowerBook G4 Battery is drastically reduced. A battery that can hold at room temperature, a medium capacity of 100%, starts at 45 ° C ambient temperature, only 70%, and even only 45% at a temperature of 60 ° C. This highlights the poor performance of some car chargers in the summer!


Lithium-ion Apple PowerBook G4 15 inch (aluminum) Battery provide a good charging in to deep as well at high temperatures. Some cells allow charging with 1.0 C from 0 ° C to 45 ° C. Most lithium-ion cells, however, prefer a lower charge current when the temperature at 5 ° C or falls below. Must be dispensed on the loading below the freezing point, as a coating can be effected by lithium metal.


The lead-acid Apple PowerBook G4 17 inch Battery is not very sensitive to extreme temperatures, as we all know, on the basis of experience with our car batteries. Part of this tolerance is the inertia of lead-acid systems are attributed. Some battery models allow a shop below the freezing point with a small charging current, while others are damaged, and provide only reduced capacitance values, and life expectancy is shortened.


To improve the loading performance of lead-acid Apple PowerBook G4 17 inch Battery at low temperatures and prevent thermal effects during the warm-up, it is important to monitor the charging voltage limits to be set. An installation of this measure can extend the life expectancy of a battery up to 15%. General guidelines recommend making a correction of about 3mV per cell per degree Celsius. The voltage correction has a negative coefficient, ie The threshold voltage decreases when the temperature rises.


Heat kills the Apple MacBook Pro 17 inch Battery! The warmer the cells shorten, the life expectancy. Higher temperatures may not always be foreseen, especially during a fast charge. It must, however, attempt to keep these periods as short as possible. While 45 ° C is temporarily tolerable, begin a battery from 50 ° C damage is increasing. Moreover, cells are warmer in the interior of a battery, always a few degrees when the temperature of the battery case.

Ultra Fast Chargers


Some manufacturers of chargers promise amazingly short loading time of 30 minutes or less. With well-balanced cells and moderate temperature can nickel-cadmium VGP-BPS10 s batteries, which are designed for fast charging, are being charged in a very short time. This is achieved with a simple increase of the charging current during the first 70% of the charge cycle.



The article Via battery blog



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