Northvolt sodium-ion batteries reach 160 Wh/kg, matching LFP

One of the biggest hurdles in recent years, as the car industry shifts from combustion engines to electric vehicles, has been the high cost of batteries.

Battery prices have not fallen at the pace forecast a few years ago - the price per kWh even increased in 2022 - so finding viable alternatives has become essential.

One option that has been gaining ground is LFP (lithium iron phosphate) batteries, which are around 20% cheaper than NMC (nickel, manganese, cobalt) batteries. Both are lithium-ion chemistries; the price difference largely comes down to the materials used.

A further, potentially even cheaper, route is sodium-ion batteries. They stand out because they do not use lithium, and with sodium being the sixth most common element on the planet, they can be 10–20% cheaper than LFP. If manufacturing scales up, they could become cheaper still.

If sodium-ion batteries can be that much more affordable, why are they not already common in electric cars? The main constraint is energy density: it is lower than LFP, which itself is lower than NMC.

Northvolt sodium-ion batteries: 160 Wh/kg and what it changes

Swedish company Northvolt, one of Europe’s largest battery manufacturers, says it has developed a new sodium-ion battery with an energy density of 160 Wh/kg. That figure is presented as a benchmark for this class and on a par with today’s LFP batteries.

“(…) I am very pleased to be able to say that we have developed a technology that will (…) accelerate the energy transition. (…) this type of battery technology is crucial to achieving global sustainability goals, making electrification more economical, sustainable and accessible around the world.”

Peter Carlsson, CEO and co-founder of Northvolt

Northvolt is not alone in the race for sodium-ion batteries. China’s giants CATL and BYD are also involved. BYD, for instance, announced just a few days ago that it will build its first sodium-ion battery factory, with annual capacity of 30 GWh.

Even so, Northvolt’s progress is welcome news for Europe. Sodium-ion batteries - and local production of them - could help reduce Europe’s growing dependence on China for supplying batteries used in European electric cars.

Advantages and disadvantages

Sodium batteries work in the same basic way as any other battery: there is a cathode and an anode, and sodium ions (rather than lithium ions) move between them, generating electricity.

Compared with NMC and LFP, these batteries are described as safer, cheaper and more sustainable, and they can be made using abundant, regional minerals (iron and sodium). On the downside, sodium is heavier than lithium and, combined with the generally lower energy density, this can mean electric vehicles end up heavier than they already are.

“Our sodium-ion technology provides the performance needed to enable longer-duration energy storage than alternative battery chemistries, at a lower cost, thereby opening up new avenues for the deployment of renewable energy generation.”

Peter Carlsson, CEO and co-founder of Northvolt

Because of the lower cost and this chemistry’s tolerance of high temperatures, Northvolt plans to take the technology beyond Europe - to markets such as Africa, the Middle East and India - using it primarily for electricity storage.

Will this sodium battery make its way into cars? It can already be used in certain types of vehicles, but probably not in mainstream electric cars for now. Northvolt says the next generation of this battery type, which promises higher energy density, will be better suited to automobiles.

Although it is already one of Europe’s largest battery makers, Northvolt was founded only in 2016 in Stockholm, Sweden. It supplies (lithium-ion) batteries to BMW, Scania, Volvo Cars and the Volkswagen Group.