The popularity of electric vehicles in the future largely depends on the progress of battery technology. The performance of batteries must meet a series of customer requirements such as endurance, charging time, power output, reliability, durability, safety and cost.
Battery system, motor and intelligent energy management system are the cornerstone of Edrive electric drive technology for BMW I series and iperformance models. BMW Group decided to develop these core components of electric drive in the early stage, just like the traditional engine. It can adjust the requirements of different specific models under different conditions, make full use of the advantages of power train electrification, comprehensively reduce fuel consumption and carbon emissions, and maintain dynamic driving experience and performance.
The battery pack manufactured by BMW factory has better temperature adaptability. Only the extremely low outdoor temperature will affect the battery performance. However, in this case, the BMW group requires that the available residual capacity of the battery is still in a wide state of charge (SOC). In addition, the battery system design requirements to meet at least 8 years of long life quality assurance period.
In order to achieve the best quality of collision safety, durability (reliability) and battery performance, scientific and rigorous production process is essential, which is the significance of BMW factory as the manufacturing center of electric drive system. The modular design system enables BMW's automotive products to have both the advantages of standardization and flexibility.
About 6000 square meters of the factory's production workshop are allocated to Edrive electric drive components, 1500 square meters are dedicated to the production of motor and battery modules, and 1000 square meters are used for battery assembly. The capacity of all equipment can be rapidly doubled in a short time without affecting the production efficiency. The idle space can further increase the overall production capacity of the electric drive system.
The dingolfinger plant produces battery packs for BMW I and iperformance in two stages. The first is a highly automated stage, in which lithium-ion batteries purchased from outside are assembled into modules, each module contains 16 battery units, which are integrated with connectors, controllers and cooling systems, and covered with aluminum shell packaging.
The battery pack needs to meet the different vehicle models loaded, usually including 5 or 6 modules. It is automatically fixed by bolts and connected by electrical connectors. Even if there is a fault, it is only necessary to replace the individual module, and the maintenance workload and risk are greatly reduced. The replacement of the module only needs to disassemble the cooling system, and other components are not involved.
The modular design principle allows battery packs with common basic characteristics and quality standards, can be customized to match different models, and each module can also be installed in the best suitable space and predetermined location in the car.
In addition, the coolant circuit of the vehicle air conditioning system is also used to cool the battery, and the gaseous coolant directly cools the battery cell. This method ensures efficient temperature control. Since the heat transfer from the evaporation process is direct, it is more efficient than the addition of additional media, making the cooling system particularly compact. At the same time, it also prevents the risk of liquid being released in case of collision.