36 Modular packs Modular design enables customisable battery pack dimensions that can be easily configured to megawatt-per-hour scale systems for a variety of heavy-duty uses. With the architecture for a major truck and bus maker, up to four packs can be configured in series, and 16 connected in parallel, to provide a wide range of capacity and packaging options for different types of EVs. There are different form factors for different vehicle applications. One has a width of 860 mm and a length of up to 2808 mm, and can contain up to 123 kWh of energy storage per pack with an output voltage up to 1200 V. For commercial vehicles with space constraints that call for a narrower battery pack, there is one form factor that can fit between the frame rails of a vehicle chassis with a width of 620 mm and hold up to 125 kWh of energy. Safety features are key for heavy-duty applications, including cell-level passive propagation resistance (PPR). With PPR, on the rare occasion that a single battery cell failed with a thermal event, it would not spread to neighbouring cells. Instead, the defective cell would remain isolated from the rest while the pack architecture allowed for proper venting away from the occupant cabin and doorways. This approach also enables a slower, more controlled release of energy over a longer period of time. Module construction The construction of a modular battery pack typically involves designing individual modules that are self-contained units, each containing a set of lithium-ion battery cells and associated electronics. These modules are connected in series or in parallel to form the larger battery pack that powers the EV. To increase the structural rigidity of an EV chassis, the design replaces traditional vehicle structures with a dynamic battery pack. This involves designing the pack as a structural component of the vehicle, rather than as a separate unit mounted on top of the chassis. By doing so, the battery pack can help to increase the overall stiffness and strength of the vehicle’s frame. One approach to integrating the battery pack into the structure of a vehicle is to use the individual modules to create a platform that runs the length of it. This platform is essentially a flat, rectangular structure that contains the battery modules and serves as the base of the vehicle. The rest of the components, such as the body and interior, are built on top of the platform. By using the battery pack as a structural component in this way, the vehicle’s weight can be more evenly distributed across its length and width, which can help improve handling and stability, particularly in high-performance EVs, where weight distribution is critical. In addition to improving the structural rigidity of the EV or reducing costs, integrating the pack into the chassis can improve the packaging efficiency of the battery cells and reduce the complexity of the vehicle’s design, as there are fewer components to integrate and connect. Mining measures One mining truck features a trolley pantograph connected to an overhead catenary line, which is a concept highly suitable for long-haul ramps. The electric trolley line gives additional assistance to the battery-electric mine truck on the most demanding stretches up-ramp while fully loaded, enabling further reach and battery regeneration during drift, which increases productivity drastically for a mining operation. A full-scale, autonomous, electric trolley system is being installed in the Rävliden mine, Sweden, with four such systems, operating at a distance of 5 km and a depth of 750 m. Swappable packs An alternative is a swapping system, which takes about five minutes, enabling the operator to stay in the cabin and removing the need for heavy mine infrastructure. This is not a trivial task. The LFP battery pack measures 1800 x 2130 x 1680 mm and weighs 8,260 kg, with a capacity of 576,000 Ah. Batteries are swapped quickly, without needing overhead cranes or forklifts. The operator drives to the swapping bay, lowers the depleted battery and retrieves a fully charged one. The 320 kW charging and water-cooling units are the same size, allowing for a variety of configurations to fit any mine, making it easy to relocate and handle multiple operations simultaneously. They are moved by forklift. Electric surface drilling rigs have long depended solely on a tethered cable as the power source. A battery-electric surface concept combines battery power with a 1 kV cable. The battery pack provides power for up to one hour of drilling, or up to seven hours of tramming. The battery is primarily intended for tramming and Focus | Battery tech for heavy-duty apps July/August 2024 | E-Mobility Engineering A module pack that fits between the chassis rail for a Class 3 light truck (Image courtesy of American Battery Solutions)
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