How did Tesla increase the power of the battery?

Recently, Tesla's 100kWh model has passed the assessment of the EU certification body RDW. This means that the Model S/X100D model is about to come out! Its mileage theory value will reach 613km(based on the NEDC standard).

According to EU regulations, models listed and sold in EU member states must be certified by their authorized agencies. RDW is a Dutch company commissioned by Tesla and can obtain a license to sell in the European Union after its certification. In this article, let's explore how this 100kWh is done?

ElonMusk once said that Tesla's endurance(power) will increase at a rate of 5 % per year. From the current iteration of the battery pack, this goal is basically achieved. In addition to the 60kWh as an entry-level configuration, 70kWh and 85kWh have been upgraded to 75kWh and 90kWh, respectively.

In the near future, 100 kWh and 120 kWh batteries will also be included in the optional list. At present, 60kWh still exists as a version of the configuration to promote Tesla's sales. What really has a story is how 70 kWh and 85 kWh each add 5 kWh of electricity.

One thing is certain, that is, the structure of the battery pack has not changed during the increase in battery power. The number of internal battery packs has not changed. Let's start with a brief idea of the internal structure of the Tesla battery pack.

There are 14 battery packs inside 60kWh, each battery pack contains 384 cores, a total of 5376 cores; 85kWh consists of 16 battery packs, each containing 444 cores, a total of 7102 cores.

The 70kWh that was added later was actually a 75kWh battery pack, which was limited by software. The extra 5kWh was initially provided to the owner as a $3,000 optional package. As long as it is updated with OTA software, 70D can be changed to 75D.

So the question is, where did the 75kWh pack come from? On this issue, Tesla officials did not provide a technical explanation. According to the author's judgment, 75kWh is actually an 85kWh battery pack, which is reduced by two battery packs. In the 85kWh battery, the capacity of each battery pack is 5.3 kWh, and 14 such battery packs are 74.2 kWh.

This is the relationship between 70kWh, 75kWh, and 85kWh. As for 60kWh, this is just a configuration to lower the entry threshold. So, how did 90 kWh get here?

From 85kWh to 90kWh, there is 5kWh more. Did you add an extra battery pack? In the 85kWh battery structure, it is no longer possible to superposition the battery pack. The only possibility is to replace the new core. Of course, it still uses the 18650 model core, but the chemical material has been adjusted to increase the energy density.

In this process, Tesla added a small amount of Silicon to the graphite anode of the core, thereby increasing the energy density of the core.

The addition of Silicon to the anode has been recognized as a way to increase energy density in the battery field. In order to avoid the continuous superposition of battery packs and the resulting mass of batteries, Tesla can only focus on the development of high-energy density cores. However, for ternary lithium-ion batteries, increasing energy density through Silicon is far from simple.

The basic principle is that after adding Silicon to the graphite anode, the structure of the Silicon atom can accommodate more lithium ions than the graphite, resulting in an increase in the absorption capacity of the anode to lithium ions. In a single charge and discharge cycle, the more anode lithium ions, the greater the energy density.

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