Super growth cycle of lithium copper foil

Lithium battery copper foil: neglected and indispensable lithium battery base material

Copper foil acts as a negative electrode material carrier and a negative electrode current collector in a lithium battery, and is an important material for lithium batteries. The harsh working environment and performance requirements of lithium batteries place many requirements on the thickness, oxidation resistance and adhesion properties of copper foil. As a key raw material for lithium batteries, the thickness, tensile strength, elongation, uniformity, surface properties and other indicators of copper foil directly affect the cycling performance and energy density of lithium batteries.

New energy vehicles push lithium battery copper foil into a new round of demand high boom cycle: three times three years

The rapid development of new energy vehicles has been deeply rooted in people's minds. Under the assumption that global new energy vehicle sales will reach 3 million units in 2020, lithium battery copper foil (including power battery and non-power battery) will be from 70,000 to 80,000 tons. Demand has climbed to around 200,000 tons. The demand for domestic lithium copper foil has climbed from 3-4 million tons to 100,000 tons, accounting for 50% of global consumption. Three years of triple growth space is worth looking forward to.

Supply is in short supply or will become the norm, the profit cycle has already started

Compared with the explosive growth of demand, lithium-ion copper foil manufacturers are obviously not ready, and supply is stretched. In 15-16 years, more companies are adjusting their product mix to meet demand, but the production and flexible production space is extremely limited. With the clearing of domestic new energy vehicle policies in the second half of the year, the contradiction between supply and demand of lithium copper foil will be intensified again. .

Considering that high capital expenditures, long construction periods, and high market/technical barriers, we expect lithium-ion copper foil to be in short supply or will remain in 2018. Lithium-ion copper foil has been fully turned to the seller's market.

The profit cycle has also started, and the gross profit margin of mainstream lithium-ion copper foil companies has climbed from 13-15% in 15 years to 23-25%.

Investment evaluation and suggestions: In summary, we believe that under the impetus of new energy vehicles, lithium copper foil will usher in a 2-3 year super growth cycle, and it is recommended to actively grasp the investment brought by three years and three times space opportunity. See the following table for specific investment targets:

Risk warning: 1) Lithium-ion copper foil production capacity released quickly, leading to a decline in industry profitability; 2) Lithium-ion copper foil demand was suppressed by new energy vehicle fraud and other policies, and fell.

1. Lithium battery copper foil: neglected and indispensable lithium battery base material

According to the application field of copper foil, copper foil can be divided into three categories: 1) copper clad laminate (CCL) and copper foil for printed circuit board (PCB), which are commonly used in electronic information industry and copper foil application. The most extensive field accounts for 80% of the total domestic copper foil output. The thickness is generally 12-70μm (standard copper foil), and 105-420μm (ultra-thick copper foil); 2) copper foil for lithium ion secondary battery, including lithium battery copper foil for power battery and lithium battery copper foil for non-power battery, It is the second largest application area of ??copper foil, accounting for about 13% of the total domestic copper foil output. The thickness is generally 7-20 microns (lithium battery copper foil); 3) copper foil for electromagnetic shielding, mainly used in hospitals, communications, military and other areas that require electromagnetic shielding.

The specific copper foil background information is detailed in the appendix. Below we focus on the lithium battery copper foil. As shown in Figure 1, lithium-ion copper foil is one of the important basic materials for lithium batteries. The lithium battery utilizes lithium ions stored in the positive electrode material and electrons to reversely move during charging and discharging to achieve normal operation. The main structures are a positive electrode, a negative electrode and an electrolyte. Lithium-ion copper foil acts as both a carrier for the negative active material and a negative electron collector and conductor in the lithium battery: 1) The lithium battery generally uniformly coats the negative electrode material (graphite) on a very thin copper foil. After drying, rolling, dry cutting and the like, a negative electrode is obtained. In the process, the copper foil acts as a carrier for the negative electrode material; 2) the negative current collector functions to collect the current generated by the active material of the battery. To produce a larger output current. The current collector has the characteristics of being as small as possible and easy to process. Copper foil has good conductivity, soft texture, mature manufacturing technology and relatively low price, which naturally becomes the preferred material for anode current collector of lithium ion battery.

Different from the public's understanding, lithium-ion copper foil has high technical requirements, and it is definitely not a copper foil. Lithium battery's harsh working environment has many technical requirements for copper foil, including: 1) very small thickness to meet the high volume capacity requirements of lithium-ion batteries; usually thickness is between 8-12μm. 2) The bonding strength with the negative active material layer is high, the surface energy can uniformly coat the negative active material without falling off; 3) the chemical and electrochemical properties are stable (anti-oxidation), and have good corrosion resistance; 4) electrical conductivity High; 5) low cost, so as to reduce the cost of lithium batteries as much as possible.

The performance of lithium battery copper foil is also closely related to the quality of lithium battery. Copper foil is a neglected and indispensable lithium battery base material. For example, the uniformity of copper foil thickness has a direct impact on battery capacity and consistency.

Furthermore, the power battery has higher requirements for lithium battery copper foil. As mentioned above, lithium-ion copper foil can be divided into two categories: power battery and non-power battery (such as 3C, energy storage, etc.); due to the large amount of lithium battery used in new energy vehicles, energy density and cycle times are high. During the work or manufacturing process, the temperature is higher, which puts higher requirements on the lithium battery foil of the power battery:

1) The yield strength requirement is higher. New energy vehicles are demanding high energy density, and when using new anode materials, higher requirements are placed on the yield strength of copper foil (stress that resists microplastic deformation).

2) High temperature stability requirements are higher. For example, in the production process of a lithium ion battery, the copper foil is heated to about 200 ° C. Therefore, it is required that the copper foil does not soften when heated at 200 ° C and maintains the initial yield strength.

3) From the perspective of weight reduction and weight reduction, higher requirements are imposed on the thickness of copper foil. In particular, pure electric vehicles are equipped with a larger number of battery cells, and only the weight of the copper foil is more than 10 kg (related to the battery capacity). Therefore, reducing the quality of the copper foil on the battery, reducing the cost of the copper foil raw material, and providing high energy density have become another requirement for the future copper foil for lithium ion batteries. To achieve this requirement, the most important way is to reduce the thickness of copper foil. At present, the thickness of copper foil of mainstream lithium-ion battery is 8~10μm (including 8μm double-sided lithium-ion copper foil for power battery, and 3C battery). It is possible to use a product of 9 μm or more or a single-faced hair). Or use a hole to reduce the weight, such as Japan's Mitsui Metals Co., Ltd. developed a copper foil with a void ratio of 50%.

4) Consistency requirements are higher. Due to the large amount of batteries used in new energy vehicles, the consistency requirements for the performance of lithium copper foil products are even higher.

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