For the aluminum foil used in Pacific Automotive Network blade batteries, the oxide layer on the copper/nickel surface is a semiconductor and the electrons are conductive. The oxide layer is too thick and the resistance is great; The oxide layer on the surface of aluminum, aluminum oxide, is an insulator and the oxide layer cannot conduct electricity, but because it is very thin, electronic conductivity is achieved by tunnel effect. If the oxide layer is thicker, the conductivity of aluminum is achieved. the aluminum foil will be of poor quality, or even insulated.
Why do lithium batteries use copper foil for the negative electrode and aluminum foil for the positive electrode - this is the reason
1. Both are used as current collectors because they have good conductivity. and a soft texture (this may also be beneficial for the cervixlage), it is also relatively common and cheap, and at the same time, a layer of oxide protective film can be formed on the surface of both.
2. The oxide layer on the surface of copper/nickel is a semiconductor, and the electrons are conductive if the oxide layer is too thick, the resistance is large while the oxide layer on the surface of the aluminum. Aluminum oxide is an insulator and the oxide layer cannot conduct electricity, but due to its very fine electronic conductivity it is achieved by tunneling. If the oxide layer is thicker, the conductivity of the aluminum foil is poor or even mediocre. isolated. Generally, it is best for current collectors to undergo surface cleaning before use, on the one hand, the oil stains can be removed, and at the same time the thick oxide layer can be removed.
3. The potential of the positive electrode is high and the endThe aluminum oxide layer is very dense, which can prevent the current collector from oxidizing. The oxide layer of the copper/nickel foil is relatively loose. In order to avoid oxidation, it is preferable to have a lower potential. At the same time, it is difficult for Li to form lithium inlaid alloy with Cu/nickel. low potential However, if the copper/nickel surface is heavily oxidized, the potential will be lower at a slightly higher potential. The Li will react with the copper/nickel oxide to insert lithium at the potential. Aluminum foil cannot be used as a negative electrode because the LiAl alloy will perform at low potential.
4. The current collector requires pure components. The impure composition of Al will make the surface film non-dense and cause pitting corrosion. Additionally, damage to the surface film will result in the formation of LiAl alloy.
(Photo/Text/Photo: QuPacific Automotive Network (estions and answers)
Pacific Automotive Network uses copper foil for blade batteries When producing blade batteries, graphite is used. used It is first mixed and stirred with auxiliary materials to form a suspension, and then applied to the copper foil. The copper foil is unfolded at a speed of 70 meters per minute. After coating, it is sent to the oven for drying and. then rolled.
Why do lithium batteries use copper foil for the negative electrode and aluminum foil for the positive electrode?
1. Both are used as current collectors because they have good conductivity, have a relatively soft texture (perhaps this will also be beneficial for bonding), are relatively common and cheap, and both surfaces can be formed. protective oxide film.
2. The oxide layer on the surfaceThis copper/nickel is a semiconductor, and the electrons are conductive if the oxide layer is too thick, the resistance is large while the oxide layer on the surface of aluminum. Aluminum oxide is an insulator and the oxide layer cannot conduct electricity, but due to its very fine electronic conductivity it is achieved by tunneling. If the oxide layer is thicker, the conductivity of the aluminum foil is poor or even mediocre. isolated. Generally, it is better to clean the surface of current collectors before use, on the one hand, the oil stains can be removed, and at the same time the thick oxide layer can be removed.
3. The positive electrode potential is high, and the thin aluminum oxide layer is very dense, which can prevent the current collector from oxidizing. The oxide layer of the copper/nickel foil is relatively loose. To avoid oxidation, it isbetter to have a lower potential. At the same time, it is difficult for Li to interact with Cu/nickel at low potential. A lithium intercalated alloy is formed under these conditions, but if the copper/nickel surface is heavily oxidized, Li will react with the copper/nickel oxide to form intercalated lithium at a slightly higher potential. Aluminum foil cannot be used as a negative electrode because the LiAl alloy will perform at low potential.
4. The current collector requires pure components. The impure composition of Al will make the surface film non-dense and cause pitting corrosion. Additionally, damage to the surface film will result in the formation of LiAl alloy.
(Images/Text/Photos: Pacific Automotive Network Calling the Beast Q&A)