How does Tesla use 18650 cylindrical and lithium-ion batteries?

How does Tesla use 18650 cylindrical and lithium-ion batteries?

Starting with a conceptual clarification: stacked batteries versus polymer batteries versus bagged batteries

The inquiry dealt with "laminated (polymer) lithium-ion batteries." It's important to note that laminated and polymer batteries are distinct concepts. nmp recovery system A polymer battery refers to one with a polymer or colloidal electrolyte, while traditional lithium-ion batteries contain liquid electrolytes. On the other hand, a laminated battery is composed of stacked electrode sheets and diaphragms, in contrast to wound cells like the common 18650 battery. Generally, polymer batteries adopt a laminated structure and can thus be referred to as laminated batteries. However, not all laminated lithium-ion batteries are polymer, as they can also use liquid electrolytes. In fact, many electric cars (such as Nissan Leaf and GE Volt) use liquid electrolytes for their laminated power batteries. This confusion may stem from the fact that both laminated and polymer batteries are often packaged in aluminum-plastic films, commonly known as "bag-like" batteries. But it's worth noting that bagged batteries can also contain coiled cells.

As far as I can tell, polymer batteries aren't used in electric vehicles at the moment, n methyl 2 pyrrolidone solvent and I suspect the main reason is that colloidal electrolytes don't conduct electricity very well, so they have a high internal resistance.

What is the purpose of Tesla's use of 18650 batteries?

Questions are what I'm asking.

How does Tesla's Battery Management System (BMS) differ from other electric vehicles?

This article mentions several reasons.

The consistency of the process

Approximately several billion 18650 batteries are shipped each year. nmp chemical They are the oldest, most mature and most stable lithium-ion batteries, widely used in electronic devices. Japanese manufacturers have accumulated a lot of experience over the years in the production process of 18650 batteries, resulting in high levels of consistency and safety in the batteries they produce.

An American battery professor half-jokingly told me that you should use the battery charging and discharging tester at the same time if you buy the same batch of batteries directly from a Japanese manufacturer. If you find different discharge curves for different channels, you should question the consistency of your device, not the battery.

In contrast, stacked lithium-ion batteries are still in their infancy (see

Is there a reason why enterprise-standard batteries are not promoted by the electric vehicle technology industry?

It is not uniform in size, size, pole position, etc., and the battery manufacturer is inexperienced, so the consistency of the battery cannot reach the standard of the 18650 battery. It is impossible to manage a large number of batteries in series or parallel if the battery's consistency cannot meet the requirements.

The 18650 battery cell capacity is limited (generally not more than 3 Ah), the number of cells required is greater (Roadster has 6831 cells), but the consistency is excellent. Stacked batteries can be made larger (30 Ah or 40 Ah) and the number of cells reduced, but the consistency is poor.

Tesla is not primarily focused on batteries and therefore lacks extensive knowledge in this area. Due to this, it is challenging for the company to dedicate significant resources and efforts towards collaborating with battery suppliers to enhance the production of stacked batteries. As a result, when creating the sports car and Model S, Tesla had no choice but to procure batteries from existing markets and establish its own battery system. From a technical standpoint, it is simpler to engineer a system that oversees more than 6,000 consistent cells compared to one with over 200 inconsistent cells. Essentially, managing a larger quantity of dependable batteries is less complex than handling a smaller amount of unreliable ones.

As opposed to the Nissan Leaf, another success story for pure electric cars, it uses a lithium-ion laminated battery. Nissan and NEC have been cooperating for a long time and have accumulated a lot of battery technology, so they should have considerable quality control experience. Nissan and NEC have formed a joint venture called AESC to manufacture the LEAF's batteries.

The development and utilization of electric vehicles and batteries by automobile manufacturers in the United States, Japan, and different countries and regions at the medium level is very interesting to compare.

Costs

With its 18,650 batteries, Tesla can build on previous production lines from Japanese manufacturers such as Panasonic. As the competition for 18650 batteries in consumer electronics gets tougher, I think Panasonic would love to work with Tesla to upgrade their product lines and produce power batteries.

Further, industrial production has scale effects. When the scale of the product reaches an order of magnitude, the cost can be greatly reduced. Tesla uses thousands of 18650 batteries, so a single battery costs very little.

Dissipation of heat

Nissan's LEAF is bold enough to use a passive thermal management system (it doesn't!). The heat is carried away by natural convection. The LEAF's single-cell battery looks like this:

The following diagram shows a battery module consisting of four cells in two parallel strings:

Battery packs consisting of 48 battery management modules connected in series look like this:

lithium-ion batteries versus bagged batteries

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