Electric cars – solid-state batteries aim to lower the price and the charging time of batteries and increase the range and the safety
Lithium-ion batteries have been essential for the past three decades, powering everything from mobile phones to surgical equipment and electric vehicles. To be attractive, electric cars must have specific characteristics: a range of at least 450 km, recharge in less than 15 minutes, cost less than £30,000, have a battery life of at least 12 years or 260,000km, and most importantly, zero chance of catching fire.
Lithium-ion batteries can catch fire due to thermal runaway when they are damaged electrically (e.g. overcharging), mechanically (drilling, crushing), or thermally (if they are brought to an excessive temperature). It is important to note that fossil fuel cars are also prone to catching fire. According to online data, electric car fires are far less common than their fossil fuel counterparts but are more violent and last longer. Unfortunately, these occurrences are no longer making headlines.
To address this issue, battery manufacturers have proposed replacing liquid or gel electrolytes with solid electrolytes to improve performance and safety.
Solid-state batteries and carmakers
Solid-state batteries are the new research focus in the field of electric cars, with the primary objective of increasing the range, reducing the price and recharging time of batteries. Additionally, introducing solid electrolytes instead of gel ones will help better manage battery pack temperatures. Batteries should not exceed 45°C when charging, and 60°C when discharging, as exceeding these thresholds could lead to chemical reactions that generate additional heat and cause explosions or fires.
The benefits of solid-state batteries will be numerous and impressive. They will have a greater energy density, safety, autonomy, life and reduced recharge times and be lighter than conventional lithium-ion batteries. They will also be cheaper and produce less CO2 during production. It is estimated that using solid-state batteries could reduce the cost of electric cars by up to 70%, making them more accessible to the public.
In response to this potential, automotive giants such as Toyota, Nissan, Ford, Volkswagen, Mercedes-Benz and BMW have invested heavily in research to develop new materials for electrolytes, electrodes and cell seals to increase the power and safety of batteries. Volkswagen has invested in QuantumScape industry solid-state battery developer. In contrast, Stellantis, Mercedes-Benz, Hyundai, and Kia have all turned their attention to Factorial Energy, Ford, and BMW to Solid Power. By investing in these cutting-edge technologies, these automotive giants are positioning themselves at the forefront of the industry for years to come.
Solid-State Battery Cell Technology
At the CES(Consumer Electronics Show) 2023, Stellantis exhibited the 100 Amp-hour solid-state battery developed together with Factorial Energy.
Proprietary FEST™ (Factorial Electrolyte System Technology) leverages a near-solid electrolyte material, enabling safe and reliable cell performance with high-capacity cathode and anode materials. Moreover, most existing lithium-ion battery production equipment can produce solid-state batteries with FEST, thus reducing production costs significantly.
“With Factorial, we are in development of a proprietary technology that uses less cobalt. Coming by 2026, the solid-state battery may deliver up to 30% higher energy density compared to conventional lithium-ion, which could enable an even longer driving range or less weight! Together, we are already working on the next generation that will push this to 50%. More with less.” said Carlos Tavares, Stellantis CEO, at CES 2023.
QuantumScape offers a solid-state lithium-metal battery instead.
The following battery characteristics can be read on their website:
“A solid-state lithium-metal battery is a battery that replaces the polymer separator used in conventional lithium-ion batteries with a solid-state separator. The replacement of the separator enables the carbon or silicon anode used in conventional lithium-ion batteries to be replaced with a lithium-metal anode. The lithium metal anode is more energy dense than conventional anodes, allowing the battery to store a greater amount of energy in the same volume. Some solid-state designs use excess lithium to form the anode, but the QuantumScape design is ‘anode-free’ in that the battery is manufactured anode free in a discharged state, and the anode forms in situ on the first charge. The QuantumScape separator material is a ceramic capable of meeting the key requirements of high conductivity, stability to lithium metal, resistance to dendrite formation, and low interfacial impedance. These are the key requirements to make a lithium-metal anode, which in turn enables high energy density, fast charge, and long life. The ceramic itself is non-combustible, making it safer than conventional polymer separators, which are hydrocarbons and so can burn. The formulation of QuantumScape’s material is proprietary, but it uses earth-abundant materials with a continuous-flow manufacturing process, which we believe will make it cost-effective at commercial volumes.”
Instead, Solid Power offers three types of solid-state battery sulfide-based solid electrolytes.
Two use Silicon or Lithium metal anode with sulfide-based solid electrolyte and NMC cathode(nickel, manganese and cobalt). The third is a conversion reaction cell, using a Lithium metal anode, sulfide-based solid electrolyte and a conversion-type cathode.“Solid Power’s sulfide-based solid electrolyte is the key ingredient that powers Solid Power’s All-Solid-State Battery Platform technology. Solid Power’s electrolytes offer the best combination of conductivity (the ability to move ions back and forth quickly), manufacturability and cell-level performance. The cell manufacturing processes we have developed are already used globally for high volume traditional lithium-ion battery cell production, which we anticipate will enable manufacturers of our all-solid-state battery cells to meet volume and cost requirements of OEMs.”
Those who fulfil their commitments and bring a reliable solid-state battery to market quickly will reap the rewards, and not only from the automotive industry. We will keep up to date with the latest advances in solid-state battery technology to see what the future holds!