Exploring the Latest Molex Battery Tech Enhancements for the Next-Gen BMW EV
BMW Group has selected the Volfinity Cell Contacting System from Molex to be used in the battery management system for its next-generation electric vehicle class, improving performance and simplifying battery system design.
BMW Group has selected Molex’s Volfinity Cell Contacting System for the carmaker's next-generation electric vehicle (EV) platform.
Volfinity Cell Contacting System. Image used courtesy of Molex
In development since 2018, Volfinity is an innovative battery interconnect solution that allows centralized monitoring of individual EV battery cells without the need for cumbersome daisy-chained wires.
The Volfinity system offers a reliable and easy-to-implement solution for battery cell monitoring, load balancing, and temperature measurement. It is designed to meet the strict functional safety requirements for EV batteries.
EV Battery Construction and Monitoring
EV, energy storage, and other large batteries are typically constructed from groups of smaller cells packaged into sub-modules. These modules are assembled to form the full, high-energy storage battery.
An EV battery pack is typically constructed from hundreds, up to thousands, of these smaller lithium-ion battery cells.
Managing the charge and discharge cycles of the battery pack is essential to the performance of an EV. The ability to accurately monitor individual cell performance within the battery pack allows for more effective battery management and improved vehicle performance.
Safety is a primary concern, as very high energy densities of an EV battery pack pose the risk of thermal runaway events that can lead to dangerous and difficult-to-extinguish hot-burning battery fires. Proper cell monitoring helps to quickly identify problematic cells and avoid operating conditions that could lead to catastrophic or other failures.
1865 and 2170 cylindrical lithium-ion automotive batteries. Image used courtesy of Panasonic
Volfinity Cell Contacting System
The Volfinity system begins with a plastic tray that lays over each battery module within the EV battery pack and hosts the bus bar and other system components. The plastic design reduces the weight added to the vehicle allowing for a longer range, an essential performance criterion in the highly competitive EV market.
Thermally efficient and flexible aluminum bus bars connect to the battery cells and relay cell data via a metal adaptor to an FPC connector. To safely manage battery operation, the FPC connector passes the cell voltage, current, and temperature data to the battery management system.
Copper bus bars on either end of the plastic tray form the positive and negative terminals of the battery module, with multiple modules connected to form the complete battery pack.
In addition to EV batteries, the Volfinity system supports batteries in fixed systems like energy storage, solar plants, and wind farms.
Features of the Volfinity Cell Contacting System. Image used courtesy of Molex
BMW Group Electrification Roadmap
A recent study from BloombergNEF found that EVs currently represent only about 3% of car sales globally, expected to climb to 28% and 58% by 2030 and 2040, respectively.
Battery module using the Volfinity system with cylindrical cells. Image used courtesy of Molex
According to BMW Group, the company delivered 433,792 battery and hybrid electric vehicles in 2022, up 32.1% from the prior year and representing a little over 18% of total sales.
BMW Group projects that electric vehicles could represent as much as 30% of their total vehicle sales by 2025, with more than 10 million EVs having shipped to customers by 2030.
