1

Definition

The electronic aluminum foil is an aluminum foil processed by a series of calendering, cleaning and cutting processes on a high-purity aluminum ingot, and is a key raw material for producing an aluminum electrolytic capacitor.


2

Introduction

After the aluminum foil is processed into a foil, it is subjected to surface etching treatment and reoxidation treatment, and then subjected to winding processing to form a capacitor. The aluminum foil before the etching is called a light foil, and the corroded aluminum foil is called a corrosion foil, and the aluminum foil after the reoxidation treatment is called a foil. Electronic aluminum foil refers to light foil, which is a key raw material for the production of aluminum electrolytic capacitors. It is divided into electronic aluminum foil and electrode foil according to the order of the manufacturing process. The electrode foil includes corrosion foil and chemical foil.

The electronic aluminum foil together with the electrolyte accounts for 30%-70% of the raw material cost of the aluminum electrolytic capacitor (which varies depending on the size of the capacitor). It can store electrical energy and can be used as the positive and negative electrodes of electrolytic capacitors.

3

Electronic aluminum foil industry chain list

As one of the most basic electronic components, aluminum electrolytic capacitors are widely used in various electronic products such as electronic information industry and home appliances. They have the characteristics of small size, large capacity and low cost, especially the price per unit of electricity. The capacitor is the cheapest, in line with the development trend of information products, and is widely used in telecommunications, home appliances, automobiles, electronics, aviation, new materials and other industries. The market demand is extremely large. At present, the output of aluminum electrolytic capacitors accounts for 45% of the total capacitor output. .

4

Electronic aluminum foil process

The electronic aluminum foil is a high-purity aluminum foil which is formed by hot-rolling a fine aluminum (high-purity aluminum) aluminum ingot into an aluminum sheet, and further cold rolling and annealing. The specific production process of the electronic aluminum foil includes: melting casting – soaking – hot rolling – pre-annealing – cold rolling – intermediate annealing – cold rolling – foil rolling – slitting – performance testing – packaging.


5

Classification of electronic aluminum foil

The electronic aluminum foil can be classified into a high voltage anode foil, a low pressure anode foil, a negative electrode foil, and the like. The high-voltage anode foil is column-like corrosion, the low-pressure anode foil is spongy corrosion, and the anode foil of the medium-pressure section is worm-like corrosion.

High-pressure anode foils can be divided into two categories, one is high-quality high-pressure foil; the other is ordinary high-pressure foil. The high-quality high-voltage anode foil is characterized by “two high and one thin”, namely high-purity, high-cubic texture and thin surface oxide film. These products are of high quality, but high cost, aluminum purity >99.99%, cubic texture 96%, vacuum heat treatment at 10-3pa ~ 10-5Pa. Ordinary high-pressure anode foil is an economical and practical high-pressure anode foil with aluminum purity >99.98%, cubic texture >92%, and vacuum heat treatment under 10-1pa~10-2pa conditions.

The negative electrode foil has a soft state and a hard state. Japan is dominated by soft electrochemical corrosion, while Western Europe is dominated by hard chemical corrosion. Both have their own advantages and disadvantages. The soft state uses high purity aluminum foil (>99.85%), no copper, excellent quality, but high cost; the hard state uses low purity copper-containing aluminum foil, and the cost is low.

6

Major producers

The production of electrode foil needs to be rolled and etched into two stages by aluminum foil. It is linked to the two industries of aluminum processing and capacitor manufacturing. The main processes are relatively independent and the difference is large. Therefore, some enterprises use the aluminum electrolytic capacitor production industry as the background. The electrode foil production line is expanding; some enterprises use aluminum refining or aluminum processing as the background to expand into high-purity aluminum smelting, aluminum foil rolling and even electrode foil production; some enterprises specialize in electrode foil production and aluminum electrolytic capacitor production. Among them, professional electrode foil manufacturers and aluminum electrolytic capacitor manufacturers are the main enterprises in the production of electrode foil, while electronic aluminum foil is mainly produced by aluminum processing enterprises. At present, there are more than 40 domestic electronic aluminum foil manufacturers.

7

Application of electronic aluminum foil

Electronic aluminum foil is widely used in capacitors. Capacitors can be divided into three categories: aluminum electrolytic capacitors, ceramic capacitors and film capacitors. Among them, aluminum electrolytic capacitors are the most widely used varieties of all electronic capacitor products. The rapid development of China’s capacitor manufacturing industry has led to an increasing demand for electronic aluminum foil. Due to the high difficulty in the production of electronic aluminum foil required for the manufacture of capacitor anodes, the current domestic supply capacity is still insufficient in the medium and high-end products, but with The supply of domestic aluminum foil products has been increasing, and this situation has changed significantly.

In 2016, China’s electronic aluminum foil production capacity was about 85,000 tons, an increase of 0.7 million tons from the 78,000 tons in 2015. In 2016, China’s electronic aluminum foil industry output was about 51,900 tons, an increase of 2.77% from 2015’s 5.05 million tons; 2016 China’s electronic aluminum foil industry market consumption of about 47,900 tons, an increase of 3.01% compared with 46,500 tons in 2015, the market size of China’s electronic aluminum foil industry in 2016 was about 1.207 billion yuan, an increase of 5.97% from 1.139 billion yuan in 2015.

8

Technical analysis of electronic aluminum foil

The production of electronic aluminum foil is a precision processing process, and the quality of the product has an important relationship with the advanced level of raw materials, control systems and production equipment. From a global perspective, although the production of electronic aluminum foil in China is developing rapidly, European and American companies still have advantages in advanced technology, especially in high-voltage electronic aluminum foil. Since the electronic aluminum foil products have strict requirements on process technology, equipment technology and production management level, it is necessary to strictly follow the process flow and follow the characteristics of the equipment in order to produce qualified products.

In recent years, with the advancement of science and technology, the main equipment used in the production of electronic aluminum foil products has been domestically produced. Nowadays, the domestic electronic aluminum foil factory uses domestically produced equipment to produce products, and the quality level has caught up to even exceed the products produced by Japan and South Korea. In the choice of control system, the technology possessed by major domestic manufacturers is not very mature, and most choose foreign control systems. Technically, domestic production lines and production processes are still imitating and using foreign technology, or choosing a technology model for cooperation with foreign capital.

In order to continuously improve the product characteristics of aluminum electrolytic capacitors, China has many related technological improvements in aluminum foil processing. The use of high-purity, high-performance aluminum foil material greatly improves the corrosion performance of the material, and the leakage current of the formed dielectric oxide film is greatly reduced; the development of advanced corrosion and formation processes further increases the specific capacity of the anode and cathode aluminum foils, and the anode light The leakage current of the foil is further reduced. In order to reduce the size and flatten the capacitor, in recent years, progress has been made in processing technology for high specific volume and high strength of aluminum foil.