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Advantages And Disadvantages Of 21700 Lithium Battery
- Sep 05, 2018 -

The 21700 battery is still very popular among battery manufacturers in the market. The 21700 battery is generally used in electric vehicles. Over time, we found that its drawbacks are still many, but this does not affect the development of the 21700 battery, but we cannot avoid it. The drawback is that it will cause different levels of influence in a certain area. Here is the answer to your questions about what advantages and disadvantages he has.

Advantages of the 21700 battery:

1. Battery energy density increased by more than 20%

The 21700 battery has a higher energy density than the 18650 battery. According to the information disclosed by Tesla, under the existing conditions, the energy density of the 21700 battery system produced by it is about 300Wh/kg, which is about 20% higher than the 250Wh/kg of its original 18650 battery system. From the test data of Panasonic's power lithium battery cells, the volumetric energy density of the 21700 battery is much higher than that of the 18650 battery cell. The energy density of the single cell is much higher than the 20% increase after the group.

2. Battery system cost drops by about 9%

Lithium big data According to the battery price information disclosed by Tesla, the 21700 power lithium battery system is expected to sell for $170/KWh, which is about 8.1% lower than the 18650 price of $185/KWh. The cost of the 18650 system is about $171/KWh. After switching to 21700, the system cost can be reduced by about 9%, reaching $155/KWh.

After the single-cell capacity is increased, the number of parts required for PACK is reduced in proportion to reduce the cost of PACK. After switching from the 18650 model to the 21700 model, the battery cell capacity can reach 3~4.8Ah, a substantial increase of 35%, the number of batteries required under the same energy can be reduced by about 1/3, and the Tesla Models electric vehicle uses 7104 18650 batteries. Series and parallel into a battery pack, on the new Models 3, after using 21700, the number of battery sections will be greatly reduced. While reducing the difficulty of system management, the same proportion of metal components and conductive connectors used in battery packs are reduced. Tesla's Pack cost accounts for about 24% of the total system cost. It is expected that the cost of battery packs will be reduced.

3. Lightweight contribution

Samsung mentioned that after switching to the new 21700 battery, the system can reduce the component and weight by 10% compared with the current battery, thereby further reducing the weight of the battery pack, and the energy density of the whole vehicle will be partially improved.

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21700 battery burns

1. Does the downstream market accept changes?

What type of battery a battery company produces is subject to a variety of factors. At present, the “positive R&D” emphasized by the new energy vehicle industry requires designing the structure from the function. This also determines that the battery model and specifications must be reversed from the use. Therefore, whether the battery model is replaced or not depends mainly on the downstream market.

Chen Yao, general manager of Shanghai Delang Power Battery Co., Ltd. believes that Tesla's approach is not necessarily suitable for all domestic battery companies. Whether the battery size needs to be changed depends mainly on the downstream application terminals. At present, the domestic 18650 still has a large market space and application range, so the large-scale change of the domestic cylindrical battery size will take a long time.

"The adaptability of the 18650 is very strong. In addition to electric vehicles, it can be digested in other fields such as 3C digital, drones, power tools, etc. But for the 21700, there is no effective industrial chain to digest these batteries. This will undoubtedly increase costs."

2. Are the equipment and processes ready?

The production equipment and production process of the 21700 battery are not ready in a day. How to layout depends on the competition strategy of the battery manufacturer.

The cost reduction of batteries is based on yield and yield. The data from the starting point study (SPIR) shows that the yield of 18650 batteries of Panasonic and Samsung SDI is generally above 98%, and the domestic yield is generally above 95%, but this still means that there will be more B products to be processed. This is a serious challenge for the 21700.

3. Does the policy support?

In addition to the market demand is not obvious and the battery manufacturing process is insufficient, the national policy on battery size standards also has a significant impact on the choice of domestic battery size.

"The "Specifications and Dimensions of Power Battery Product Specifications for Electric Vehicles" formulated by the Ministry of Industry and Information Technology, the recommended cylindrical battery models are only 18650 and 32650. Once forced, it will be unfavorable for other types of batteries." Jiangsu Sol New Energy Technology Ji Weiyuan, chairman of the company, believes that the 21700 and other types of cylindrical batteries will form a trend in the future, but if the country's battery size standards are not explicitly supported, the development prospects of this type will not look so good.


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