Digital battery

With the popularity of digital cameras, rechargeable batteries have been in the daily lives of citizens, can be seen everywhere as one of the essential daily needs. The new curriculum standards in high school physics elective module 2-1 explicitly require that students “know the power of the emf and internal resistance. But also “discuss the lithium Laptop battery, nickel-hydrogen batteries, nickel-cadmium batteries of the main characteristics and application of the respective occasion. In this paper, these three types of ordinary rechargeable batteries for a short introduction.

 

1, the main parameters of rechargeable batteries

The rechargeable battery of five main parameters: the battery capacity, rated voltage, internal resistance, the termination voltage and discharge voltage for charge termination. Battery inside the battery capacity of many decisions of active substances, usually milliamps (mAh) said, 1 000 mAh is capable of 1 A discharge current 1 h, converted to the charge contained in the amount of about 3 600 C. The battery positive and negative electrical potential difference between the nominal voltage of the battery. Rated voltage of electrode materials, electrode potential and electrolyte concentration of the internal decision. When the ambient temperature variation condition, a slight change in the output voltage of the battery; In addition, the battery voltage output and the battery charge remaining there some relationship between the amount of. Nickel Under normal circumstances, cell-cadmium batteries rated voltage of 1.3 V (usually seen around 1.25 V), cell Ni-MH IBM ThinkPad R32 battery 1.25 V, cell lithium-ion battery 3.6 V. The battery internal resistance of the resistance of the plate and the impedance of ion flow from the decision in the discharge process loads, the plate resistance is unchanged, but resistance to the flow of ions is responsible the concentration of electrolytes and changes in the ion change. In general, cell nickel cadmium battery internal resistance for the 7 ~ 19 mW, cell nickel-metal hydride battery internal resistance of 18 ~ 35 mW, lithium-ion battery cell internal resistance of 80 ~ 100 mW.

 

Rechargeable battery is fully charged, the most active substances board has reached the saturation point, then continue to charge the battery voltage does not increase the voltage currently known voltage charge termination. Cell-nickel-cadmium battery charge termination voltage of 1.75 ~ 1.8 V Ni-MH battery 1.5 V lithium-ion battery 4.2 V. Termination voltage discharge is the minimum allowable battery voltage discharge. If the voltage is below the battery voltage discharge termination of the discharge, the battery voltage decreased rapidly at both ends to form a depth of discharge, so that the resultant formation of a council where he is not easy in the resume normal load, thus affecting the battery life. Ceasing discharge voltage and flow, speaking generally, the cell nickel-cadmium battery discharge voltage termination of 1.1V, Ni-MH battery for 1 V, lithium-ion battery 2.7V

 

2, nickel-cadmium batteries (Ni-Cd)

Nickel material of the cathode cadmium Dell Inspiron B120 battery nickel hydroxide and the mixture of graphite powder, the negative electrode material for sponge powder and cadmium oxide powder of cadmium, the electrolyte is usually sodium hydroxide solution or potassium hydroxide. It should be noted that nickel-cadmium batteries before charging, the battery is composed of water, the reaction occurred in the positive and negative plate has a precipitation of oxygen and hydrogen. Bubbles gathered at the plate surface of the plate will reduce the surface involved in chemical reactions and increase the resistance of the internal battery. These gases, if not rapidly compounds in water, the pressure inside the battery would be increased considerably, which would damage the battery, the pressure is too large, sealed batteries will open porosity, so the oven electrolyte, but he repeated the release stomatal gas furnace, the viscous nature of the electrolyte increase the transmission of ions between the plates becomes difficult, the internal resistance of the battery will increase dramatically reduce battery capacity.

 

Nickel-cadmium hp F4809A battery process, if not all power has begun to charge over, the next, and then discharge, you can not release the total amount of money. For example, battery-nickel-cadmium is only 80% of the fee paid after after the start of the load is fully charged, the battery can only release 80% of home electricity, a phenomenon called “memory effect”. The main discharge appeared in some off camera is set too high, the battery is completely discharged each time the equipment is automatically closed, and if the battery will be serious long term “memory effect” may be more more capacity for less electricity. “Memory effect” is mainly due to the drum part of the discharge, the nickel hydroxide is not completely in the nickel hydroxide and nickel hydroxide remaining will be combined to form larger crystals, larger crystals generally difficult to restore, which causes the reduction of active substances inside the battery.

 

Nickel-cadmium batteries were first used in mobile phones, laptops, and other types of batteries, it is resistant to more load capacity and discharge, maintenance is simple, parallel bars, electric oven deep fried . But compared to nickel-hydride batteries, metal and lithium-ion batteries in terms of there are many disadvantages, such as loading and unloading process if not handled properly, there will be serious “memory effect”, greatly reducing the lifespan; Cadmium is toxic, and therefore nickel-cadmium VGP-BPS10 battery is not conducive to eco-environmental protection. Many gaps, nickel-cadmium batteries are now largely been eliminated from the scope of digital cameras.

 

3 nickel-hydride batteries, metal (Ni-H)

Ni-MH battery capacity nickel-cadmium batteries large, usually about twice as its main component of the nickel hydroxide positive electrode material negative alloy mainly pollution, dust free, the electrolyte is 30% potassium hydroxide aqueous solution. Reaction of nickel-hydride batteries, metal and nickel-cadmium batteries is similar to overcharging, the precipitation plate positive oxygen precipitation plate negative hydrogen. However, due to large surface of the catalyst of the hydrogen electrode, hydrogen can easily be extended to the hydrogen electrode surface, hydrogen and oxygen may be relatively easy to fit into the battery and combine to form water, so that the gas pressure inside the container essentially unchanged. Even so, long after the overcharge, the battery inside the pressure is too high, it may explode.

 

Ni-MH battery also has the effect of memory, but relatively low in nickel-cadmium batteries. Ni-MH batteries or nickel-cadmium toshiba PA3191U-4BRS battery memory effect can generally be put through several depth charges for the relief depth. Deep-discharge battery is usually necessary to put in the termination voltage is down to a single cell is usually below 1 V, but not too low, otherwise permanent damage will result in greater. Better not use the equipment for in-depth self-discharge, in particular, is a wire and a small bulb connected to the battery positive and negative measures of repression are more desirable because it can not control blood discharge, the voltage is too low will seriously damage the battery. Recommended with a function of discharge and protective equipment against overload charge to make deep and deep discharge.

 

Ni-MH battery internal resistance is low, high discharge current, discharge voltage changed very little, and easy to recycle batteries, damage to the environment are minimal, its costs and low prices, as the ‘DC power supply is a battery of very high quality. Ni-MH batteries can be used to create the column of rechargeable batteries, clocks, electronic games, digital cameras, video cameras, and some laptops have applied.

 

4 Li-ion battery (Li)

Li-ion apple M8403 battery is divided into two broad categories: non-rechargeable and rechargeable. Non-rechargeable batteries called disposable, it can be only one time chemical energy into electrical energy, electrical energy can be restored to chemical energy such as lithium-manganese dioxide. Known as the secondary rechargeable batteries, which is commonly known as lithium-ion battery (Li-Ion). The cathode is a lithium-ion batteries containing lithium transition cathode metal oxide is a carbon material such as graphite, the electrolyte is a lithium salt-containing organic solution. Cells both positive and negative or in the battery separator, the lithium-ion form are based there. The battery work, the lithium ions in the positive and negative electrodes and an electrolyte membrane in directional movement. When the battery is charging, the cathode to the electrolyte release Lithium-ion, this process is de-embedded; anode electrolyte in lithium-ion inhalation, this process is integrated. The process of discharging the battery and the situation at hand, such a charge and discharge when the lithium-ion intercalation and de-embedded process, as if the same rocking chair rocking, it was said that the image of lithium-ion batteries for “rocking chair batteries.

 

Lithium-ion batteries and nickel-cadmium batteries and nickel-metal hydride batteries in comparison, there are many advantages. Lithium-ion battery memory effect did not exist, the same capacity, the size is very small, using a voltage of 3.6 V, is a nickel-cadmium batteries, nickel-hydride batteries in three metal time and can be used in a wide range of temperatures (-20 ℃ ~ 60 ℃), while nickel-metal hydride TravelMate 290 battery (0 ℃ ~ 50 ℃). At the same time lithium-ion battery self-discharge rate is relatively low. Self-discharge rate is defined as a period of time, the battery is not used in the circumstances, an automatic loss of electricity for the percentage of total capacity. Generally, at room temperature, nickel-cadmium batteries self-discharge rate of 13% per month, 15%, Ni-MH battery for a month 25% ~ 35%, while the lithium-ion battery is only 5 % ~ 8% per month.

 

But lithium-ion batteries are also some areas unsatisfactory. Such as: lithium-ion batteries have life, usually for two years and do not use the state is stored for some time, some of its capacity would be permanently lost. Lithium-ion battery anode and cathode material from a plant has already begun its failure in history, different temperatures and state of battery charge saturation, the impact is different from data in Table 1 ( capacity accounts for the remaining percentage of the initial capacity) of the column.

 

Thus, the higher the storage temperature and charge the battery more saturated, more severe loss of capacity. So I do not recommend long-term preservation Lithium Ion battery, if there are idle hands of the VGP-BPS10B battery and the storage time should not exceed 40% charge level, temperature, preferably less than 15 ℃ or less. The nickel-hydride batteries, metal and nickel-cadmium batteries are almost not subject to aging effects of long-term storage of nickel-based charge batteries for deep discharge after a few deep can be restored to its capacity of origin. But the charge deep deep discharge can not be restored the ability of lithium-ion batteries and cause permanent damage to the positive and negative electrodes. Since the molecular level, the excessive discharge of carbon anode will lead to excessive release of lithium-ion batteries, while showing the lamellar structure collapsed, an overload of the lithium-ion battery will go too hard in the structure carbon negative, while making some of the lithium-ion batteries can not be released.

Lithium at the same time, battery charge and ion time of discharge only 400 to 600 times, specially modified products, but many times 800. The number of nickel-metal hydride rechargeable batteries generally able to reach more than 700 times, some good quality office products and output up to 1 200 times.

 

Because of the many advantages of lithium-ion battery is still optimistic about its potential applications, mainly in digital cameras, camcorders, mobile phones, PDAs, laptops that use power. Lithium-ion batteries currently in the hot area of research should be used in vehicles, electricity and gasoline and used motor vehicles or hybrid electric vehicles. Same time, people also develop a real sense of the solid state lithium batteries, lithium-ion battery completely eliminate the organic liquid, as well as safe and reliable lithium battery