Smaller, Cheaper Electric Car Batteries with Advanced Technology

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【Summary】Stellantis is collaborating with battery manufacturer Saft on a project called Ibis to reduce the number of components in electric car batteries. The project incorporates microinverters and chargers into each battery module, eliminating the need for on-board chargers and high-voltage inverters. This approach aims to make batteries smaller, cheaper, and more suitable for small EVs. However, it may not align with Volkswagen's concept of fitting individual cells directly into the car's chassis.

FutureCar Staff Sep 14, 2023 9:22 AM PT

Smaller, Cheaper Electric Car Batteries with Advanced Technology

Sometimes, the most straightforward ideas are right in front of us, waiting to simplify already relatively simple engineering, like electric car batteries. Compared to internal combustion engines (ICE), electric vehicles (EVs) eliminate the complexity of fueling systems, exhaust systems, and emission-treatment equipment.

While EVs are mechanically simpler and do not require catalysts, complex transmissions, or exhausts, the science and electronics behind them are quite advanced. Stellantis, a car manufacturer, recently announced its ambitious plan to reduce battery weight by half. The company has been collaborating with battery manufacturer Saft on a project called the Intelligent Battery Integrated System (Ibis), which aims to further reduce the number of components in an EV.

EV powertrains typically consist of several key components. The battery stores and charges direct current (DC) electricity, while the electric motors run on alternating current (AC) like a household supply. To convert AC to DC and vice versa, there is an inverter per motor. Additionally, the powertrain includes an on-board charger that converts AC current from the grid to DC for the battery.

Electric car batteries, or battery packs, are composed of numerous small, low-voltage lithium-ion cells arranged into modules. Each module can have a different voltage, depending on the pack's size and design, even though the overall battery may generate 400V or 800V.

The Ibis project takes inspiration from photovoltaic systems to simplify EV hardware. In solar power generation systems, multiple solar panels produce DC electricity, which is then fed to a single inverter to convert it to AC. Alternatively, individual panels can have microinverters that convert DC electricity to AC as it leaves each panel. The Ibis project adopts a similar approach by embedding a microinverter and charger in each battery module. This eliminates the need for an on-board charger and high-voltage inverter(s) in EVs.

As a result, the complete battery pack produces AC current, making it ready for the motor. Stellantis believes that this approach will benefit smaller EVs where space is limited. It is also expected to be cost-effective since several smaller charger and inverter electronics are cheaper than their high-voltage counterparts that they replace.

While the Ibis project showcases innovative thinking that improves EV technology, it may not be compatible with other concepts, such as Volkswagen's "Cell2Car" initiative, which aims to directly integrate individual cells into the car's chassis.