What Is a Voltaic Cell?

A dry battery is a voltaic battery that uses an absorbent (such as wood chips or gelatin) to make the contents a paste that does not spill out. Often used as a power source for flashlight lighting, radios, etc. After years of development of dry cell technology in China, problems such as specific energy, cycle life, and high and low temperature adaptability have been broken.

[gn diàn chí]

Dry cell is a chemical battery that uses paste electrolyte to generate direct current (wet battery is a chemical battery using liquid electrolyte). Dry cell is a primary battery. It is widely used in daily life and is lightweight. battery. it

During the "Eleventh Five-Year Plan" period, the size of China's dry battery market expanded rapidly. The average output increased rapidly at an annual rate of about 20%, and the overall size increased by two times, from about 70 million KVAh in 2005 to 14.41668 million KVAh in 2010. . In 2011, the scale of production and sales of China's dry battery industry has expanded, and profits and sales profits have increased significantly, and the industry's operating efficiency has been relatively good. In 2011, the total assets of China's dry battery industry were 88.091 billion yuan, an increase of 39.35% year-on-year; sales revenue was 96.515 billion yuan, an increase of 32.40% year-on-year; total profit was 5.720 billion yuan, an increase of 10.81% year-on-year. At the same time, after many years of development of dry battery technology, its specific energy, cycle life, and high and low temperature adaptability have been broken. At present, China is gradually narrowing the gap with leading international technologies, and has reached the international level in some core technologies, and has increasingly entered the international market.

One day in 1780, when Italian anatomist Luigi Galvani was dissecting a frog, he held different metal instruments in both hands and accidentally touched the frog's thigh at the same time. The muscles of the frog's leg immediately twitched. It seems to be stimulated by electric current, and if you only use a metal device to touch the frog, there is no such reaction. Galvani believes that this phenomenon occurs because of an electricity generated inside the animal's body, which he calls "bioelectricity."

In 1799, Volt immersed a zinc plate and a silver plate in salt water and found that a current passed through the wire connecting the two metals. So, he put a lot of zinc flakes or silver pads on them soaked in salt water-soaked velvet or paper, and stacked them flat. When you touch both ends with your hands, you will feel a strong current stimulation. Volt successfully used this method to make the world's first battery "volt stack." This "volt stack" is actually a battery pack connected in series.

In 1836, British Daniel improved the "Volt Stack", and successively came out better "Bunsen batteries" and "Groove batteries". However, at that time, no matter what kind of battery was filled with liquid between the two metal plates, the handling was very inconvenient, especially the battery used liquid is sulfuric acid, which is dangerous when moving.

The originator of dry batteries was born in the mid-19th century. In 1860, France's George Leclanche invented a carbon-zinc battery. This battery was easier to manufacture, and the initially wet and aqueous electrolyte was gradually replaced by a viscous paste-like method. When it was packed in a container, , "Dry" batteries appeared.

In 1887, the Englishman Wilhelm Hellesen invented the earliest dry batteries. Compared to liquid batteries,

With the development of science and technology, dry batteries have developed into a large family, so far there are about 100 kinds. Common zinc-manganese dry batteries, alkaline zinc-manganese dry batteries, magnesium-manganese dry batteries,

ordinary

Pay attention to the following points when purchasing dry batteries:

1. Select the battery as required. For example: used in flash, camera, MP4,

Dry batteries are also called primary batteries. We often use dry batteries in daily life, such as No. 5 and No. 7 batteries. Dry batteries have the annoying drawback of self-discharge. Self-discharge is not only related to the internal factors of the battery, but also to the ambient temperature and humidity. After a certain period of storage, the performance of the battery will be reduced due to self-discharge. It is necessary to use a large number of dry batteries for selection.

Commonly used dry battery selection methods: Pay attention to check the production date, the shorter the storage period, the better; use a multimeter DC 500 m A to block and measure the short-circuit current. This method is simple but inaccurate and not safe. The essence is judged by the instantaneous short-circuit current. The internal resistance is as small as possible.

If using the voltage measurement method twice is safe and reliable, connect two 2.2 V small electric beads in parallel and lead out two clips with wires. First measure the open circuit voltage of the battery, then clamp the small electric bead clip on the test lead, and then measure The applied voltage after the load from the pool is compared, the smaller the difference between the two voltages is, the better.

This method is more practical to discriminate 6 ~ 9 V laminated cells, and small beads should be connected in series. Except for rechargeable batteries, other disposable batteries are also available. It is more accurate to use digital voltmeter for measurement.

In 2003, the State promulgated the "Technical Policy for the Prevention and Control of Pollution from Waste Batteries," which stipulated that from 2005, production of alkaline zinc-manganese batteries with a mercury content of more than 0.0001% will be stopped. Today, with the advancement of technology and the updating of production processes, most dry batteries mainly contain elements such as iron, zinc, manganese, and no longer contain heavy metals such as mercury and lead. Many dry batteries have also been labeled with "Lead and Mercury Free" labels.

According to the relevant person in charge of the Municipal Environmental Protection Bureau, these dry batteries can now be transported to domestic waste incineration landfills with domestic waste , which is convenient and economical. But for historical reasons, many people are unaware. Under the condition that the processing conditions are not perfect, if the waste dry batteries are processed in a centralized manner, it will cause some pollution, which can be dispersed into the garbage bags and discarded.

Battery industry recycling is the most called topic. Domestic and international strict regulations have been made on the mercury content of dry batteries. Dry batteries on the market can be disposed of with garbage. However, if too many dry batteries are collected in one place, or dry batteries If the environmental protection index is not reached, from the perspective of resource reuse, there is still a market space for dry battery recycling and utilization. From the main categories of dry batteries, zinc-manganese batteries and alkaline zinc-manganese batteries, recycling can obtain metals such as mercury, zinc, cadmium, and completely solve the pollution caused by the battery. For dry batteries, there are three main recycling technologies, which are: manual sorting, fire recycling, and wet recycling.

I. Manual sorting method: After classifying dry batteries into carbon batteries and alkaline batteries, mechanically dissect them, and then manually separate zinc skin, manganese dioxide (requires further mercury removal), carbon rods, plastic covers, etc. This is a method focusing on full recycling.

Second, fire method recycling: dry batteries ^[1]

First, the nominal voltage is, in popular terms, the road-end voltage during normal operation, strictly speaking, the average voltage from the time when the new battery voltage reaches the minimum voltage. The voltage of a new battery or a battery that has just been charged will be slightly higher than the rated voltage, it will fall to this value immediately after it is used, and it can be maintained at this value for a long time thereafter. When the voltage is lower than this, the battery voltage will drop rapidly until it becomes unusable.
Second, capacity: the battery's electrical energy, generally used mAh, 500mAh means that the battery discharges at 50mA current, can work for 10 hours. This kind of measurement is rough because the working time of batteries with different properties is not linearly proportional when discharged with different currents. Therefore, the stricter battery capacity is expressed by how many ohmic resistors can be discharged and how long, and the discharge method also has differences such as continuous, gap and short time. For example, for a certain brand of alkaline battery, for a 10 ohm load, the continuous discharge time to 0.9 volts is 20 hours; for a 1.8 ohm load, the discharge is 15 seconds per minute, and the number of discharges to 0.9 volts is 660 or more. The former discharge conditions are equivalent to larger recorders or ordinary electric toys, while the latter is similar to flash charging. The more novel and high-quality batteries, the better the linearity of capacity.
3. Storage period and self-discharge rate. Generally, disposable batteries have a storage time of about 2-3 years. This is due to the discharge effect of the battery in free placement. Because of the high self-discharge rate of rechargeable batteries, the self-discharge rate is generally directly given, which is a few percent per month ([%] / month).