What is the difference between alkaline and nickel-metal hydride batteries?

Also known as zinc-manganese battery, it is the most common dry battery at present. It has the characteristics of low price and safe and reliable use. Based on environmental considerations, it still needs to be recycled because it still contains cadmium, so as not to cause damage to the global environment. ■Alkaline Battery, also known as alkaline dry battery, is suitable for large discharge and long-term use. The internal resistance of the battery is low, so the current generated is larger than that of the ordinary manganese battery, and the environmentally friendly mercury content is only 0.025%, and no recycling is required. ■ Mercury battery SilverOxideButtonCell mercury battery, because of pollution and capacitance, has gradually been replaced by lithium-manganese formula ■ Lithium battery ■ Ni-Cd (NickelCadmiumBattery) has been widely used by the public early, can be repeated about 500 times Charge and discharge, but after about 10 charge and discharge, memory effect will occur; The other disadvantage is that during charge and discharge the cathode will grow acicular crystals of cadmium, sometimes penetrating the partition and causing internal dendritic crystal Short circuit. Due to the cadmium content, it must be recycled. ■Ni-MH rechargeable battery Ni-MH (NickelMetalHyorideBattery) is a mainstream rechargeable battery in the market. It uses nickel oxide as the anode and a metal alloy that absorbs hydrogen as the cathode. Generally, it can be charged and discharged more than 500 times. Since it does not contain mercury and cadmium, it does not have to be recycled. ■Lithium rechargeable battery RechargeableLithiumionBattery ■Lead acid battery SealedLead-AcidBattery ■Solar battery In the chemical battery, according to the ability to use the charging method to restore the battery storage energy, it can be divided into primary battery (also known as primary battery) and secondary battery (again A battery, commonly known as a rechargeable battery, can be reused many times. The primary battery can be divided into six series of common zinc manganese (neutral zinc manganese), alkaline zinc manganese, zinc mercury, zinc air, magnesium manganese and zinc silver; secondary batteries mainly include nickel-cadmium batteries, nickel-hydrogen batteries, and lithium. Type such as ion batteries, alkaline manganese rechargeable batteries, and lead storage batteries. In digital devices, commonly used battery types are dry batteries (including alkaline batteries), nickel-cadmium batteries, nickel-hydrogen batteries, and lithium-ion batteries. Dry battery: This is one of the most common types of batteries used. Many people have used dry batteries, but not many people understand the structure. Generally, our commonly used dry batteries are also called zinc-manganese batteries (Figure 1). It can be divided into carbon-zinc battery (Carbon-Zinc) and zinc chloride battery (Zinc-Chloride), which has the advantages of high energy density, appropriate current density, and easy mechanization. In the hypermarket, these two types of batteries were boxed and sold at a low price. However, it is a pity that due to insufficient energy density, the battery is generally only used for electronic products that consume less power, such as alarm clocks, calculators, etc. If you plan to use him to drive your digital camera, I am afraid you will be disappointed. Cylindrical zinc-manganese batteries can be classified into paste zinc-manganese batteries and cardboard zinc-manganese batteries due to the difference of separators. Among them, cardboard zinc-manganese batteries are different in electrical properties due to differences in formulation composition, and are also classified into C-type cardboard batteries (carbon zinc batteries), also known as high-capacity batteries; P-type cardboard batteries (zinc chloride batteries), also known as High power battery. The dry batteries in the general supermarket or retail market are all such batteries, which are labeled SuperHeavyDuty. The power capacity of the "C" type is about 20% lower than that of the "P" type battery. Generally, the batteries that are supplied with the goods are mostly such batteries. The packaging of the dry batteries is divided into paper shells (used in "C" type), PVC, iron shells and There are four types of packaging, such as lead, and the difference in the amount of mercury (basic standard is 15ppm) is also different between environmental protection and non-environmental protection. Alkaline zinc-manganese battery (Zinc-MnO2): is an important role in dry batteries. This type of battery is what we often call "alkaline batteries". Due to the large capacity and long-lasting use of current, the demand for such batteries is increasing. However, some manufacturers' alkaline batteries are non-environmental mercury-containing batteries, because the addition of silver oxide to the components can increase their electrical capacity by more than 30%, but at the same time the retail price is relatively high. Alkaline batteries have been the most successful high-capacity batteries to date, and are one of the most cost-effective batteries. They have changed the internal structure and electrochemical system of traditional batteries, and have adopted extremely pure and active positive and negative electrodes. Material, its discharge capacity is 5-7 times that of ordinary dry batteries, and its storage life is more than twice that of ordinary batteries.

Nickel-metal hydride batteries are a good battery. Nickel-metal hydride batteries are classified into high-voltage nickel-hydrogen batteries and low-voltage nickel-hydrogen batteries. The positive electrode active material of the nickel-hydrogen battery is Ni(OH)2 (called NiO electrode), the negative electrode active material is metal hydride, also called hydrogen storage alloy (electrode called hydrogen storage electrode), and the electrolyte is 6 mol/L potassium hydroxide solution. Nickel-hydrogen batteries have become more and more important as an important direction for hydrogen energy applications.

Since fossil fuels have become less and less in the case of large-scale development and utilization of human beings, the development and utilization of hydrogen energy has received increasing attention in recent years. Nickel-hydrogen batteries have become more and more important as an important direction for hydrogen energy applications. Although nickel-metal hydride batteries are indeed a good performance battery,special nickel-metal hydride batteries are high-voltage nickel-hydrogen batteries (hydrogen pressure up to 3.92 MPa, or 40 kg/cm2). Such high-pressure hydrogen is stored in thin-walled containers. It is easy to explode, and nickel-metal hydride batteries also need precious metals as catalysts, making its cost very expensive, which is difficult to accept for civilian use. Therefore, foreign low-voltage nickel-metal hydride batteries have been explored since the 1970s. Nickel-metal hydride batteries are classified into high-voltage nickel-hydrogen batteries and low-voltage nickel-hydrogen batteries. High-voltage nickel-metal hydride batteries were first developed in the early 1970s by M. Klein and J. F. Stockel of the United States. The trend of replacing nickel-hydrogen batteries with nickel-hydrogen batteries and applying them to variousspecials has been formed.

The positive electrode active material of the nickel-hydrogen battery is Ni(OH)2 (called NiO electrode), the negative electrode active material is metal hydride, also called hydrogen storage alloy (electrode called hydrogen storage electrode), and the electrolyte is 6 mol/L potassium hydroxide solution. The process of forming the electrode sheet of the active material mainly includes sintering type, slurry type, foam nickel type, fiber nickel type and inlay type. The electrodes prepared by different processes have large differences in capacity and large current discharge performance. The battery is produced according to a process using different conditions. Most of the consumer batteries such as communication use a slurry-type negative electrode and a foamed nickel-type positive electrode to form a battery. The charge-discharge chemical reaction is as follows [1]:

Positive electrode: Ni(OH)2+OH-=NiOOH+H2O+e-

Negative electrode: M+H2O+e-=MHab+OH-

Total reaction: Ni(OH)2+M=NiOOH+MH

Note: M: hydrogen alloy; Hab: adsorption of hydrogen; the process of the reaction from left to right is the charging process; the process of the reaction from right to left is the discharge process.

Ni(OH)2 and OH- of the positive electrode react to form NiOOH and H2O during charging, and release e- together to form MH and OH-. The total reaction is Ni(OH)2 and M to form NiOOH, hydrogen storage alloy hydrogen storage; discharge In contrast, MHab releases H+, H+ and OH- to form H2O and e-, NiOOH, H2O and e- regenerate Ni(OH)2 and OH-. The standard electromotive force of the battery is 1.319V.

Nickel-metal hydride batteries are classified into high-voltage nickel-hydrogen batteries and low-voltage nickel-hydrogen batteries.

The low-voltage nickel-hydrogen battery has the following characteristics: (1) the battery voltage is 1.2~1.3V, which is equivalent to the cadmium-nickel battery; (2) the energy density is high, 1.5 times or more of the cadmium-nickel battery; (3) the rapid charge and discharge, low temperature Good performance; (4) sealable, strong resistance to overcharge and discharge; (5) no dendritic crystal formation, can prevent short circuit inside the battery; (6) safe and reliable, no pollution to the environment, no memory effect. [1]

The high-voltage nickel-hydrogen battery has the following characteristics: (1) High reliability. It has better over-discharge and over-charge protection, and can withstand high charge and discharge rates and no dendrite formation. Has a good ratio characteristic. Its mass specific capacity is 60A·h/kg, which is five times that of cadmium nickel batteries. (2) The cycle life is long, up to thousands of times. (3) Fully sealed and less maintenance. (4) The low temperature performance is excellent, and the capacity does not change significantly at -10 °C. [1]

NiMH batteries should be maintained during use.

(1) Avoid using the process of charging. Within the cycle life, the use process should not overcharge, because overcharge easily causes the positive and negative electrodes to swell, causing active material shedding and diaphragm damage, conductive network damage and battery ohmic polarization to become larger.

(2) Prevent deterioration of the electrolyte. During the cycle life of Ni-MH batteries, the hydrogen evolution of the battery should be suppressed.

(3) Storage of nickel-metal hydride batteries. The nickel-metal hydride battery should be stored in a fully charged state. If the battery is stored for a long period of time without storing electrical energy in the battery, the function of the battery negative hydrogen storage alloy will be weakened and the battery life will be shortened.

(4) Charging after the battery is exhausted. Nickel-metal hydride batteries and nickel-cadmium batteries have the same "memory effect", that is, if the battery is repeatedly charged while the battery is still in the middle of the discharge, the battery will soon be unavailable.

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