SES Ignites Battery Talk With Its Hybrid Lithium Metal Cell

Qichao Hu made most of the video presentation about SES’ technologies. Thanks to him, we now know that the Hermes and Apollo cells are simply development stages of the company’s hybrid lithium metal cells.

SES calls them hybrid because they mix elements from solid-state lithium metal cells and current lithium-ion batteries. The explanation for that idea is an interesting one. Regular lithium-ion cells are easy to manufacture but have low energy density and a flammable electrolyte. Solid-state lithium metal cells have a high energy density but are challenging to manufacture, which would make them impractical for industrialization.

With a hybrid approach, SES claims to have kept the best of both worlds: the manufacturability of normal lithium-ion cells with the high energy density of lithium metal. The company would have achieved that with a few technical achievements.

The first is a proprietary high concentration solvent-in-salt electrolyte that is self-extinguishing in the case of thermal runways. However, taming dendrites was only possible with a protecting polymer coating on the lithium metal anode. Apparently, that's the only solid-state battery technology SES decided to use. The company did not mention if the separator is a common one or also something used by solid-state cells.

Regarding dendrites, SES did not prevent them from growing. What it did was to make them change from the needle-like shape that could perforate the separator and blow up the battery to a lot denser and flatter structure that looks like a soft speed bump instead. In other words, it does not penetrate the separators.

A third step the company adopted was to create an AI-powered (artificial intelligence) safety software to monitor battery health. This system was named Avatar because it behaves like the hybrid lithium metal battery to try to predict issues with it.

That leads us to the Hermes and Apollo batteries we mentioned a while ago. Instead of cells for different applications, they are actually “parallel development tracks,” as Qichao defined them. Hermes aims to test new materials. Apollo’s goal is to evaluate manufacturing processes for automotive batteries. The SES founder then presented the Apollo. It was the first time it was publicly disclosed.

The Apollo is an impressive cell that delivers 107 Ah, 935 Wh/l, and 417 Wh/kg with a weight of 982 grams. That’s 60% more energy density than the best lithium-ion cells currently used in electric cars, which have a 260 Wh/kg energy density. That means that battery packs with them and the same size of current battery packs with regular lithium-ion cells could deliver 60% more range.

They could also be more than 60% smaller for the same range. If the battery packs were just 60% smaller to present the same capacity, electric cars would travel further than today, thanks to the weight savings. Another impressive aspect of Apollo is that it could recover 90% of charge from a 10% SOC (state-of-charge) in just 12 minutes with the adequate fast chargers.

At this point, Qichao set the battery world on fire by stating he does not believe in solid-state cells. According to the executive, SES’s ability to offer high energy density at a wide temperature range is what made his company drop efforts to develop these batteries.

Solid Power and QuantumScape are betting on them and said they will have production versions of these batteries by 2024 and 2025. The SES founder said his company is the only one working on joint development of lithium metal cell A samples with car companies: GM and Hyundai. That would give anyone the impression that they are just around the corner, but that is not the case.

Qichao said SES will build a lithium metal cell factory in Shanghai in 2023. With 300,000 square feet (27,870 square meters), it will have an annual capacity of 1 GWh. According to the executive, it may seem small compared to lithium-ion battery plants being built nowadays – most of them with a 40 GWh annual capacity – but it would be impressive for lithium metal cells.

The executive also released a timetable for the development of SES’ hybrid lithium metal cell. B/C samples are to be produced in 2024, and mass production would be reached in 2025, one year after QuantumScape said it would start delivering its solid-state cells. Solid Power has recently announced a partnership with SK Innovation for producing these batteries. Both these competitors also have the support of carmakers: Volkswagen for QuantumScape and BMW and Ford for Solid Power.

The only thing that matters for regular car buyers is that lithium metal cells seem to be getting closer to production. Thanks to multiple efforts, we’ll eventually be able to buy EVs with safer, more robust, and lighter cells, regardless of who can deliver them first.