A group of researchers from China claims to have set a new energy density record when they developed a battery pack with a reported capacity of 711 watt-hours per kilogram – roughly three times more than the Tesla Model 3 ‘4680’ cell.
Concerns about battery capacity in electric vehicles (EVs) have been one of the primary concerns for operators in both the passenger and commercial automotive industries.
Increasing the storage of battery packs while keeping their weight as low as possible has become a key area of interest for manufacturers, as they try to convince operators still using internal combustion engine (ICE) vehicles that range anxiety is a thing of the past.
The team, led by Beijing-based National Research Center for Condensed Matter Physics professors, Li Hong and Xiqian Yu, submitted their work to the journal, Chinese Physics Letters, in March 2023, where they described the 10 amp an hour soft-pack lithium battery.
Pouch cells or ‘soft’ battery designs have the majority of the cell’s critical components encased in a protective aluminium-coated plastic or polymer film.
Only two metallic rectangular tabs protrude from the pouch: the positive and negative electrode terminals. The positive terminal, also called the anode, was created from ultra-thin lithium and the negative terminal, known as a cathode, from magnesium oxide.
Both the anode and cathodes for the team’s novel high-density battery were rigorously tested by scientists at the China North Vehicle Research Institute in Fengtai, Beijing, according to a news report from the technology website, Interesting Engineering.
To up the cell’s capacity, the team increased the charge-to-discharge range, also called C-rate, while ensuring that the cathode and anode were robust enough to maintain their integrity during the more intense charging and discharging process.
They also investigated methods to boost electrolyte efficiency within the battery and improved reversibility (recharging) issues that come with ultra-thin lithium on surfaces with large areas.
The resulting product, according to the research study, was a battery with a recorded energy density of 711.30 watt-hours per kilogram and an energy density volume of 1 653.65 watt-hours per litre.
While the team’s work is extremely promising, Li warned that the research was still in its early phases. He said the primary focus of the mission was to maximise energy density and that his team would need to address areas of concern such as durability, life expectancy and dangerous operating temperatures.