Chinese researchers develop the first semi-solid-state EV battery with a massive 620-mile range — but questions remain | Daily Reports Online
- New battery could dramatically increase EV range
- Semi solid-state chemistry boasts 30% greater energy density
- Higher density, reduced weight and a smaller form factor promised
Researchers from the Nankai University in Tianjin, China, have reportedly developed and tested a semi solid-state battery that delivers a 30% increase in energy density when compared to some of the leading lithium-ion batteries currently on sale.
According to an announcement by the researchers (via Live Science), the current iteration of its semi-solid-state battery pack delivers an energy density of 288 Wh/kg at the system level, when cooling systems, wiring, structural supports and safety hardware are considered.
The energy density of the pack in isolation is said to be 500 Wh/kg, while scientists say they are already working on iterations could exceed 340 Wh/kg at the pack level.
With a smaller form factor, a lower weight and an increased overall energy density, the Nankai University team claims that the 142kWh production version of its research pack enables an EV driving range of over 1,000 km after installation, which is more than 620 miles on a single charge.
Details remain unclear on what EV was used during the testing and whether these are official China Light-Duty Vehicle Test Cycle (CLTC) figures. But reports state the technology is already undergoing iterative upgrades and is expected to achieve a battery system energy density exceeding 340 Wh/kg, a total pack capacity of over 200 kWh and a driving range exceeding 1,600 km — almost 1,000 miles of driving on a single charge.
It is worth noting at this point that both Europe’s WLTP testing cycles and North America’s EPA figures are far less generous than those quoted in China, while real-world driving conditions reduce range figures even further.
A rule of thumb is to subtract around 30% from those claimed figures to get close to something an EV owner can achieve under real driving conditions. So 620 miles quickly becomes around 430 miles and 1,000 miles becomes 700 miles.
Still, that’s hugely impressive when compared to the range quoted by some of the leading lithium-ion technology currently on sale. According to Live Science, the Nankai University battery relies on a lithium-rich manganese cathode and a hybrid solid-liquid electrolyte system.
The hybrid design combines the advantages of the solid-state architecture with a “super-wetting” composite electrolyte, which is intended to improve ionic conductivity and safety.
“Super wetting refers to the electrolyte spread across and fully penetrating the surfaces and pores of battery materials, maximizing contact between itself and active materials so ions can move more efficiently,” the report states.
According to the statement released by Nankai University, the battery technology also introduces lithium anode technology for the first time, which addresses the issues of “high cost and high risk associated with the use of metal lithium strips”, apparently simplifying the manufacturing process, reducing production costs and achieving “significant breakthroughs” in battery cycle life and safety.
Analysis: A huge leap if true
We must caveat this with the fact that the results come from a university-industry collaboration with the Technology Center of China Auto New Energy and have not yet been independently verified in peer-reviewed research.
However, if the claims are true, the researchers are already working on semi-solid-state battery technology that could exceed 340 Wh/kg at the pack level. Pair this with an admittedly enormous 200kWh total capacity pack and range could effectively push past the 1,000-mile mark.
While this is exciting, it feels like a huge jump from where we are at today.
For example, MG recently became one of the first global manufacturers to widely introduce semi-solid-state battery technology in its MG 4 model.
In this case, the pack includes just 5% liquid in the electrolyte, yet has an energy density of 180Wh/kg, delivering a 333-mile range on the CLTC tests from a 53.95 kWh pack.
To reach the heady levels of a 1,000-mile range, the Nankai University researchers are suggesting almost quadrupling the battery capacity, which would naturally have a massive impact on the physical size and weight of the pack, not to mention the associated cost implications.
That said, researchers claim that by drastically increasing the energy density, this would in-turn lead to smaller form factors and a reduced weight.
If that’s the case, we could well be looking at EV battery technology that far outweighs combustion engine counterparts when it comes to the distance travelled between stops.
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