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What is the difference between soft pack lithium ion battery and aluminum shell lithium ion battery?

The wide application of lithium-ion batteries makes us more familiar with lithium-ion batteries. However, as far as lithium-ion batteries are concerned, most people just stay in the use stage. In order to improve everyone's understanding of lithium-ion batteries, this article will introduce the differences between soft-pack lithium-ion batteries and lithium-ion battery packs and aluminum-shell lithium-ion batteries. If you are interested in lithium-ion battery-related content, you might as well continue reading.

①Application field

Soft-pack lithium-ion batteries are mainly used in mobile Internet, mobile power and digital products such as smart phones, laptops, cameras, and so on.

Lithium-ion battery packs have a wide range of application scenarios, such as small computer rooms, low-voltage rooms and other indoor sub-systems, new energy outdoor sites, communication base stations, indoor and outdoor non-air-conditioned sites, radio and television, military, petroleum and meteorological and other unmanned sites.

②Structural characteristics

The key material used in the soft-pack lithium-ion battery, the biggest difference lies in the soft packaging material (aluminum-plastic composite film), which is the most critical and technically difficult material in the soft-pack lithium-ion battery. Flexible packaging materials are usually divided into three layers, namely outer barrier layer (usually an outer protective layer composed of nylon BOpA or pET), barrier layer (middle layer aluminum foil) and inner layer (multifunctional high barrier layer).

Lithium-ion battery pack: Lithium-ion battery is assembled as a lithium-ion battery pack with higher energy ratio, longer service time and longer life. The important constituent materials of lithium-ion battery packs are positive and negative electrodes, electrolytes, and separators.

③Energy ratio and weight

The weight of the soft-packed lithium-ion battery is 40% lighter than the steel shell lithium battery of the same capacity, and 20% lighter than the aluminum shell battery; the steel shell battery of the same size and size has a capacity of 10-15% higher, and 5-10% higher than the aluminum shell battery.

The energy density of lithium-ion battery packs is 3 to 4 times that of lead-acid batteries, 2.5 times that of nickel-cadmium batteries, and 1.8 times that of nickel-metal hydride batteries. Therefore, when the battery capacity is equal, lithium-ion batteries will be better than lead-acid batteries. , Ni-Cd and Ni-MH batteries are smaller and lighter in weight.

The aluminum shell of lithium-ion battery is designed with square and rounded corners. The material of the aluminum shell is generally aluminum-manganese alloy. The important alloy components it contains are Mn, Cu, Mg, Si, Fe, etc. These five alloys are used in lithium-ion batteries. Clad aluminum shells play different purposes. For example, Cu and Mg can improve strength and hardness, Mn can improve corrosion resistance, Si can enhance the heat treatment effect of magnesium-containing aluminum alloys, and Fe can improve high-temperature strength. Lightweight and safety, as well as the resulting performance advantages, have made lithium-ion battery aluminum shells the mainstream of the shell. The lithium-ion battery aluminum shell is currently evolving to high-hardness and light-weight technology, which will supply the market Lithium-ion battery products with superior technology.

In areas with higher consumption levels, such as European and American countries, the use of soft-packed lithium-ion battery packs has an advantage. In most developing countries, such as India and the Middle East, aluminum shell batteries have obvious advantages.

In terms of technological maturity, aluminum case technology is very mature, and it does not require high material technology (such as inflation rate, expansion rate, etc.), and there is no technical barrier in the industry; soft-pack lithium-ion batteries currently have many technical problems to be To solve the problem, especially in the battery cycle expansion index, most battery cell factories still have not solved the problem. The degree of automation of aluminum shell battery manufacturing is higher than that of lithium-ion battery pack soft-pack batteries. Therefore, the impact of human factors on product consistency is reduced to a certain extent, and labor costs are saved at the same time.

In terms of manufacturing costs, aluminum shell lithium-ion battery materials have been fully localized, while aluminum-plastic film materials for soft-pack lithium-ion battery packs still need to be imported, and aluminum-case batteries have lower battery material technical requirements than soft-pack lithium-ion batteries. Therefore, under the same capacity, the overall material cost is about 10% lower than that of soft-packed lithium-ion batteries. In addition, the finished product processing is simple, reliable and has obvious cost advantages. . In addition, the finished aluminum-shell lithium-ion battery is easy to process, and the pack lithium-ion battery pack is reliable and has obvious cost advantages.

Soft-pack lithium-ion batteries are mainly targeted at the mid-to-high-end market, and the profit margin per unit product is relatively high. Under the same output conditions, the relative profit is higher than that of aluminum-shell lithium-ion batteries, and the capital return cycle is also short. As aluminum shell batteries are prone to scale effects, product qualification rates and costs are easy to control, both currently have considerable profits in their respective market areas.

The aluminum shell lithium ion battery adopts the laser sealing process, and the soft pack lithium ion battery adopts the hot melt process. In terms of airtightness, the aluminum shell battery is superior to the soft pack lithium ion battery, which prevents aging and air leakage at the seal; the soft pack lithium ion battery The burst pressure of the battery is much smaller than that of the aluminum shell battery. Due to the aluminum-plastic composite film packaging, the mechanical strength of the soft-packed lithium-ion battery is not high. In the event of a safety accident such as an internal short circuit, the battery is easy to blow up and exhaust, reducing the risk of explosion , While the aluminum shell battery adopts a fully sealed process, under the same conditions, the air pressure is not easy to discharge, which increases the potential safety hazard.

The mass energy density of soft-packed lithium-ion battery packs is higher than that of aluminum-shell batteries. For batteries of the same size (2Ah~5Ah), soft-packed lithium-ion batteries are about 10%-20% lighter than aluminum-shell lithium-ion batteries. With the gradual increase in technological maturity, the lithium-ion battery pack has the potential to replace aluminum-shell lithium-ion batteries, and the advantages will be further highlighted.


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