from chemistry to pack
Control and driving contactors is important for safety, lifetime and energy consumption. The system level view of the control is covered by another post. Contactor Control is another one of those areas where responsibility is divided between a vehicle’s system level control and the battery management control. From the systems engineering perspective; The battery management … Read more
Contactors are the only moving part in a battery pack and although simple there are a number of contactor faults that will stop the operation of the battery pack. Introduction to Contactors There are two main types of contactors: Normally Open (NO) and Normally Closed (NC). A NO contactor does not allow current to flow … Read more
for Cell Contacting Systems and Busbars Aluminium busbar products are used in manifold applications in batteries and battery systems due to their favourable structural, physical, and chemical properties. When it comes to cell contacting systems and busbars, electrical (and thermal) conductivity are decisive for balancing component resistance and cross-section to meet the designed space. However, … Read more
Volkswagen ID Family cars such ID 3, 4, 5, 7, Buzz are based on a Modular electric drive matrix (MEB) Chassis. This Chassis contains the battery pack built into the floor for optimal weight distribution. The MEB can be scaled for cars to SUV to Vans thus allowing for standardized components especially battery modules and … Read more
What is the optimal busbar joint overlap? It should be noted that the experimentally derived optimum is for plain busbars and does not include a hole for the fixture. Braunovic [3] shows the impact on resistance of the joint overlap. The resistance ratio is the ratio of the resistance measured across the joint divided by … Read more
The Electrical Contact Resistance at a metal to metal contact is primarily governed by: The surface structure can be further described by the surface flatness, surface oxidation and water adsorption. These joints in a battery pack will either be welded or bolted. Initially the easiest to think about is the bolted busbar joint. The bolt … Read more
When the battery pack contactors are closed onto a motor and inverter there will be an inrush of current into the inverter capacitor. This very high current is at a minimum likely to age the contactors, it could permanently damage the contactors. Therefore, when we closed the contactors on the battery pack we do this … Read more
The isolation resistance of the complete HV system to ground with the contactors closed should be >500Ω/V and hence for a battery pack its resistance target must be specified by the HV System designer, typically >1,500kΩ. The NHTSA list values for a Tesla in their Tech Note [4] : The VW ID4 manual [5] states: … Read more
EV current sensors are basic components. They perform two major tasks. They help us to know how much energy we use. Also, the second task is avoiding overcurrents. Therefore, current sensors are a major sub-systems of a battery design. EV current sensors can include resistive or magnetic elements based on their structure. We use these … Read more
Contactor selection is an iterative process that includes consideration of system specifications as well as failure scenarios. Most of the contactor manufacturers share necessary information in datasheets. Thus, a wise approach would be making a comparison table to cover basic specifications like thermal and mechanical initially. System Specifications After pre-selection based on datasheet values, we … Read more