Prismatic lithium-ion battery
Prismatic lithium-ion battery usually refers to batteries with aluminum shell or steel shell. The popularity of prismatic battery is very high, with the rise of automotive power lithium-ion batteries in recent years. The contradiction between car range and battery capacity is increasingly prominent, China domestic EV manufacturers mostly use aluminum shell prismatic battery with higher energy density, because the structure of the prismatic battery is relatively simple, unlike cylindrical batteries using higher strength stainless steel as the shell and with explosion-proof safety valve and other accessories, so the overall accessory weight of prismatic battery is light, the relative energy density is high. Prismatic batteries have two different production technology: winding and lamination.
However, because prismatic lithium-ion batteries can be customized according to the size of the product, there are thousands of models on the market, thus there are too many models, it is difficult to unify the process. There is no problem with prismatic batteries in general electronic products, but for industrial equipment products that are connected in series and parallel, it is best to use standardized cylindrical lithium-ion batteries, so that the processing technology is guaranteed, and it is easier to find replaceable batteries in the future.
Pouch lithium-ion battery
The key materials used in pouch lithium-ion batteries, such as positive electrode materials, negative electrode materials and separators, are not much different from traditional steel-shell and aluminum-shell lithium-ion batteries. The biggest difference lies in the soft packaging material (aluminum-plastic composite film). It is the most critical and technically difficult material in pouch lithium-ion batteries. Flexible packaging materials are usually divided into three layers, namely the outer barrier layer (generally an outer protective layer composed of nylon bOPA or PET), the barrier layer (middle layer aluminum foil) and the inner layer (multifunctional high barrier layer).
The packaging material and structure of the soft-pack battery give it a series of advantages. For example, the safety performance of the soft-pack battery is good. The soft-pack battery is structurally packaged with aluminum plastic film. When safety problems occur, the soft-pack battery generally It will bulge and crack, instead of exploding like steel-cased or aluminum-cased batteries; it is light in weight, and the weight of soft-pack batteries is 40% lighter than steel-cased lithium-ion batteries of the same capacity, and 20% lighter than aluminum-cased lithium-ion batteries; Small internal resistance, the internal resistance of the pouch battery is smaller than that of the lithium-ion battery, which can greatly reduce the self-consumption of the battery; the cycle performance is good, the cycle life of the pouch battery is longer, and the attenuation after 100 cycles is 4%~7% less than that of the aluminum case. The design is flexible, the shape can be changed to any shape, it can be thinner, and new battery cell models can be customized and developed according to customer needs. The disadvantages of pouch batteries are poor consistency, high cost, and prone to leakage. High costs can be dealt with through large-scale processing, while liquid leakage can be dealt with by improving the quality of aluminum plastic films.
Technical Characteristics
1. Battery shape: Prismatic lithium-ion batteries can be of any size, so they are incomparable to cylindrical batteries.
2. Rate characteristics: There are process limitations for welding multi-pole tabs of cylindrical lithium-ion batteries, so the discharge rate characteristics are slightly worse than the prismatic multi-pole tab method.
3. Discharge platform: The same positive electrode material, negative electrode material, and electrolyte are used, so the discharge platform is theoretically the same. However, the internal resistance of the prismatic battery has a slight advantage, so the discharge platform is slightly higher.
4. Product quality: The cylindrical lithium-ion battery process is very mature, the probability of common secondary slitting defects of pole pieces is low, and the winding process is more mature and automated than the lamination process. The lamination process is still using a semi-manual method, so there is a negative impact on the quality of the battery.
5. Welding of tabs: The tabs of cylindrical lithium-ion batteries are easier to weld than prismatic lithium-ion batteries. Prismatic batteries are prone to false welding, which affects battery quality.
6. Pack into groups: Cylindrical batteries are relatively easier to use, so the pack method is simple and has good heat dissipation effect. When packing prismatic batteries, the heat dissipation problem must be dealt with.
7. Structural features: The chemical activity of the corners of prismatic batteries is poor, and the battery performance will decline significantly after long-term use.
We are also able to supply different types of lithium battery cells from CATL, GOTION, BAK, EVE, BYD, LG etc
