Key Clean Production Technologies for the Battery Industry - Power Environmental Protection

1. Promotion of technology

1. Mercury-free button-type alkaline zinc-manganese battery technology and equipment

Mercury-free button alkaline zinc-manganese battery The key technologies mainly include battery steel shell structure and surface coating treatment, negative electrode mercury-free alloy zinc powder material, positive electrode manganese dioxide material and electrolyte process formula, with mercury content less than 0.0005%. The key indicators are leak-proof and storage performance. The promotion of this technology can achieve mercury-free button alkaline zinc-manganese batteries and reduce mercury consumption by 110 tons per year. At present, the annual output of button alkaline manganese batteries has reached more than 8 billion, of which 10% have achieved mercury-free.

2. Mercury-free, cadmium-free and lead-free technology for cardboard zinc-manganese batteries

Mercury-free, cadmium-free and lead-free cardboard zinc-manganese batteries, that is, the mercury, cadmium and lead contents are less than 0.0005%, 0.002% and 0.004% respectively. The key points of this technology are that the negative electrode zinc cylinder alloy components and mechanical processing performance, organic and inorganic additives are combined into corrosion inhibitors to replace mercuric chloride, electrolyte and positive electrode formula. At present, the output of cardboard zinc-manganese batteries is about 18 billion, of which nearly 10% of the products have achieved mercury-free, cadmium-free and lead-free. The promotion of this technology can make use of existing production lines to achieve mercury-free, cadmium-free and lead-free cardboard zinc-manganese batteries, reducing the annual consumption of lead by 336 tons, cadmium by 118 tons and mercury by 4 tons.

3. Winding sealed lead battery technology

This technology uses a rolled lead grid and a wound electrode structure to improve high current discharge performance and high and low temperature performance, increase the power density of lead-acid batteries, and reduce lead consumption per unit power density by 1/4. Wound sealed lead-acid batteries can replace existing starter lead-acid batteries and be used in ordinary automobiles and engineering vehicles. They can also be used as power batteries in mild hybrid electric vehicles and lightweight electric vehicles. At present, this technology has formed mass production capacity.

4. Manufacturing technology and equipment for lead-acid battery plates of wire drawing, punching, continuous casting and rolling

The positive and negative plates of lead-acid batteries are made of grids as carriers of active materials. The drawn grid technology uses cold extrusion to make the grid metal structure dense, significantly improve corrosion resistance, and the grid is thinner than other processes, reducing lead consumption and reducing lead smoke and lead slag emissions. New grid manufacturing technologies also include punching and continuous casting and rolling process technologies. At present, the above processes are mainly achieved through large-scale production through the introduction of foreign technical equipment.

5. Cadmium-free lead-acid battery technology

Cadmium-free technology is to use lead-calcium multi-element alloy or other cadmium-free grid alloy to replace cadmium-containing grid alloy, and the cadmium content is less than 0.002%. The promotion of this technology can reduce cadmium consumption by 1,800 tons per year and eliminate the risk of cadmium pollution in the production, recycling and regeneration of lead-acid batteries. Currently, cadmium-free lead-acid batteries account for about 15% of electric bicycle batteries.

6. Lead-acid battery internal formation technology

At present, some automobile starting batteries, electric bicycle batteries and other products use external formation process for polar plates, which produces a large amount of acid mist and acid-containing lead wastewater. Promoting the internal formation process of lead-acid batteries can greatly reduce the generation of lead-containing acid wastewater and acid mist, and reduce the discharge of lead-containing wastewater by about 6 million tons per year.

2. Application Technology

1. Mercury-free technology for paste-type zinc-manganese batteries

Paste zinc-manganese battery is a low-priced traditional product with a total output of about 4 billion. Its characteristic is that the positive electrode uses natural manganese dioxide or activated manganese dioxide, but this material has many impurities and it is very difficult to achieve mercury-free. Mercury-free technology mainly includes improving the purity of positive electrode materials, using new materials, adjusting the electrolyte formula, replacing mercuric chloride with a combination of inorganic and organic additives, and using existing production lines to achieve mercury-free products. The promotion of this technology can reduce the annual consumption of mercury by 22 tons. The technology has been successfully developed and can be applied for demonstration.

2. Externalization of lead-acid battery plates without water washing process

The washing process after the lead-acid battery plate is formed externally generates a large amount of lead-containing and acid-containing wastewater. The lead-acid battery plate externally formed water-free washing process uses a special treatment liquid, or uses the discharge and reverse charging protection method to treat the formed plate, so as to achieve the purpose of externally forming the plate without water washing, which can reduce the discharge of lead-containing wastewater by 90%. At present, this technology has been successfully developed and has the conditions for pilot application.

3. R&D Technology

1. Develop mercury-free technology for silver oxide batteries

Silver oxide batteries are mainly used in high-end electronic watches and electronic instruments. The mercury content of silver oxide batteries is about 1% of the battery weight, but they enter the environment directly after being discarded, posing a pollution risk. In the absence of a silver oxide battery recycling and treatment mechanism, we need to start from the source and accelerate the development of new zinc powder alloys, mercury substitute additives, electrolyte process formulas, and battery steel shell structure and surface treatment process technologies to achieve mercury-free silver oxide batteries.

2. Develop new lead-acid battery technology

The development direction of new lead-acid batteries is to reduce lead consumption, improve battery mass energy density, mass power density, cycle life and fast charging capability. At present, the focus is on the research of high-performance electrode materials and preparation methods, the research of new battery structures and manufacturing processes, and the improvement of energy density and power density. New lead-acid batteries include bipolar sealed batteries, super batteries, foamed graphite batteries, etc., among which: (1) Bipolar sealed batteries. This battery adopts a bipolar structure and uses a new ceramic material as a diaphragm. Compared with traditional batteries, it has low lead consumption, light weight and small size. It has the characteristics of long cycle life, high charge and discharge efficiency, low price and easy recycling. (2) Super battery. Carbon is used to partially or completely replace the lead in the negative electrode. This type of battery has the characteristics of long cycle life, high charge rate, good power characteristics, excellent low temperature performance and light weight, and can be used as a power source for electric vehicles. (3) Foamed graphite battery. The technical innovation of foamed graphite grid sealed batteries is that the lead grid is abandoned, the active material is retained, and foamed graphite is used instead of lead, which reduces 70% of lead compared with ordinary lead-acid batteries.

3. Lead reduction technology for power lead-acid batteries

Research and select lead reduction additives and desulfation additives to reduce the polarization of lead-acid batteries during discharge, overcome the sulfation of the plate surface, reduce the internal resistance of the battery, improve the power characteristics of lead-acid batteries, reduce the capacity of high-power lead-acid batteries such as starter batteries, and reduce lead consumption by more than 10% on the existing basis. Lead reduction technology includes the use of ultra-thin plate technology. This technology has been maturely applied abroad, and is currently in the research and development stage in my country.

4. Large-scale harmless recycling technology of waste lead-acid batteries

The risk of lead pollution in the recycling of used lead-acid batteries is relatively high. At present, the key technology and equipment for recycling used lead-acid batteries mainly rely on imports. It is necessary to increase the research and development of core technology processes and equipment with independent intellectual property rights in mechanical crushing, sorting, lead paste desulfurization, lead regeneration and other links, develop comprehensive prevention and control and utilization technology and equipment for wastewater, waste gas and waste residue pollution, and realize the large-scale harmless recycling of used lead-acid batteries.