Li will drive an ET7 with a 150-kWh battery pack from Shanghai on December 17 at 6:30 am local time and live-stream his experience.

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William Li, founder, chairman and CEO of Nio (NYSE: NIO), will be testing the company's 150-kWh battery pack in person, heralding the semi-solid-state battery's imminent entry into service.

"At 6:30 am tomorrow (December 17), I'll be driving from Shanghai with Tencent News' Huang Chenxia in an ET7, and together we'll test just how far the 150-kWh battery pack can support the vehicle on the highway," Li said today in a post on the Nio app and Weibo.

Nio's NT 1.0- and NT 2.0-based models have completed validation and regulatory filings for the pack, and the team has conducted a variety of tests in which the pack has exceeded expectations for performance, including range, Li said.

Some time ago, three users in the Netherlands drove an ET7 in a non-stop relay, covering 6,000 kilometers in 72 hours and 51 minutes, from the northernmost point to the southernmost point of the European continent, setting a record for the shortest time for an EV over the same mileage, he said.

"Inspired by them, I decided to drive myself to test the highway range performance of the 150-kWh battery," Li wrote.

Li's test will be live-streamed in whole, and Chinese users will be able to watch it on several platforms including the Nio App, its WeChat account, and Tencent News platforms.

He Xiaopeng, chairman and CEO of (NYSE: XPEV), retweeted Li's Weibo post with a kind reminder that Li should prepare an extra-large cup of coffee, as this is supposed to be the longest live broadcast about EV range.

Nio unveiled the 150-kWh semi-solid-state battery pack when it unveiled its flagship sedan, the Nio ET7, on January 9, 2021 at the Nio Day 2020 event.

The battery pack has gone through several delays over the last almost 3 years and has not been officially made available so far. Nio will be holding Nio Day 2023 on December 23, where an updated timeline on when the battery pack will be available is likely to be announced.

The semi-solid battery's cell supplier is Beijing WeLion New Energy Technology, which began delivering the cells, which have an energy density of 360 Wh/kg, to Nio on June 30.

Prior to that, Nio filed with China's industrial regulator on May 9 to add WeLion as a cell supplier for three models, the first time the company had declared the use of the battery, and on October 16, Nio filed for the use of the battery for an additional 11 models.

WeLion saw its first volume installation of the power cell in November, also signaling that the pack may have begun mass production.

WeLion installed 0.41 GWh of power batteries in November and ranked 12th in China's power battery market with a 0.92 percent share, according to data released on December 11 by the China Automotive Battery Innovation Alliance (CABIA).

CABIA publishes a ranking of the top 15 battery makers with the highest installed base of power batteries in its monthly report, and that was the first time WeLion has been one of the top 15 in the overall market.

It's worth noting that the semi-solid battery pack will have a high cost due to the new technology.

The 150-kWh pack costs almost as much as an ET5 sedan, Nio co-founder and president Qin Lihong said February 11 at a user event in Changzhou, Jiangsu province.

However, a key advantage for Nio is that the vehicles support battery swap, which allows owners to rent the battery on an as-needed, short-term basis. This allows owners to experience the long range while not having to carry an expensive battery pack all the time.

Nio's semi-solid-state battery supplier WeLion sees 1st major installations in Nov