As power densities increase and power assemblies become more complex, design engineers need robust, cost-effective power coupling solutions to handle a growing range of applications.
Building on long experience in developing power interconnects for the automotive industry, Interplex has introduced the new BusMate® power busbar coupler family to provide targeted solutions to deliver efficient power interfaces for applications such as electric steering motors, motion control, traction drive, power conversion, inversion, distribution, and other emerging EV mobility requirements.
BusMate® combines a small footprint to conserve PCB space with a large ampacity-to-size ratio for handling increasing power densities. To accommodate a variety of production requirements, the busbar power couplers are available in either SMT format or proven eye-of-the-needle solderless Press-Fit interfaces. The SMT versions can be delivered in standard tape-and-reel packaging for high-speed automated placement. Depending on the configuration, BusMate® power busbar couplers can provide robust 40 to 60 Amp interfaces (SMT or Press-Fit) or up to 60 to 80 Amps (SMT versions only).
Floating Contact Technology
BusMate® is designed to ensure a low and stable contact resistance while allowing for wide positional tolerance of the mating blade in all three axes. It achieves this through a proprietary design of multiple floating contacts that adjust to the mating blade while maintaining optimal contact physics and beam mechanics.
Interplex’s Floating Contact Technology assures consistent high-power coupling by automatically compensating for variations in blade alignment. This pluggable technology can accommodate large assembly tolerances of +/- 8mm offset and up to +/- 16 degrees of twist. In addition, the Floating Contact Technology can handle a range of insertion depths and accommodate up to three re-mating cycles with no loss of performance.
Compensation for Tolerance Variations
The BusMate® power busbar couplers’ ability to compensate for a wide range of tolerance variations in the blade-to-connector interfaces without any loss of power means design and production engineers gain significant leeway in managing the assembly process. Robust power coupling is consistently achieved with just a simple plug-in step and without the need for expensive alignment mechanisms or secondary operations.
Range of Standards-based Options
BusMate® is designed to interface with 0.8mm blades that are commonly used for power connections in the automotive industry with some options for 1mm thick blade as well. In addition, they are constructed with high temperature materials that are rated to 150°C (tested to 125°C). This provides ample safety margin for deploying the busbar power couplers in automotive applications.
High Current Carrying Capabilities and High-Power Density
BusMate® is designed to deliver high current capacity for high power density applications. As shown in Figure 3, BusMate® has been tested and confirmed to meet the rated specifications of 40 to 80 Amps, using wire connections in a typical convective air, ambient cooling situation.
In addition, BusMate® was created with a range of deployment options in mind. For example, as shown in Figure 4, the current ratings for the standard components can be significantly improved with thermal management designs using active or passive cooling techniques to lower ambient temperatures.
Designed for Applications-Specific Configurability
BusMate®’s small footprint and SMT options enable creation of a variety of connector arrays to handle different mating configurations such as board-to-blade, board-to-board, and blade-to-blade. This makes BusMate® ideal for applications such as transformer-to-PCB, converter bus to PCB, both DC and AC sides of inverters, as well as many custom variations.
As power systems and modules in the automotive industry become more complex and power densities increase, the need to integrate a variety of functions and minimize size while improving power efficiency will be critical for success.
Robust and configurable power busbar coupling devices provide key interface points that are vital to deliver the needed performance and also to streamline production processes for reducing costs and enabling rapid production ramp-up to high volumes with high yields.
BusMate® is currently available in a range of different product offerings including the following:
IPX30013 – BusMate® 9-Lam Press Fit, rated for 40 to 60 amps (for 0.8mm and 1mm thick mating blade)
IPX30035 – BusMate® 9Lam-Lam SMT, Rated for 40 to 60 amps (for 0.8mm and 1mm thick mating blade)
IPX30055 – BusMate® 14-Lam SMT, Rated for 60 to 80 amps (for 0.8mm thick mating blade)
BusMate® Dimensional Layouts
The following information is provided to help with the design and assembly of products using the BusMate® Connector technology.
Busbar Assembly Tolerances
Mating Busbar Design
The mating busbar or blade must be designed with a coined tip to facilitate a low mating force and minimal marking on the plated surfaces. The busbar should be plated with tin (or silver) over a nickel underplate to maintain a low and stable contact resistance for the life of the product.
Printed Circuit Board Design
Press-Fit Version (IPX30013)
Material – The printed circuit board for the Press-Fit version should be made from FR-4. It should be constructed to meet the requirements in IPC-6012.
Board Thickness – The printed circuit board thickness should be 1.6mm or thicker depending on the application The minimum recommended thickness is 1.4 mm. When using varying board thicknesses, it is important to ensure proper contact engagement in the Z-direction for each variant.
Surface Mount Version (IPX30035 & IPX30055)
Material – The printed Circuit PCB can of various construction from FR-4, Ceramic, metal or other various materials as long as it meets industry standard requirements.
SMT Pad Design – To ensure that the BusMate® Connector sits securely in the printed circuit board, the specification of the solder pad given in Figure 6 must be met.
Press-Fit Version (IPX30013)
BusMate® Connectors are designed to be installed using automation. Press-Fit IPX-30013 BusMate® is packed in industry standard Tubes with 50 pieces per Tube. The press-in process can be performed using a simple toggle press or a machine. A press-in tool that records the necessary force and travel distance is recommended. Consistent quality is assured in this way. The ram speed should be between 25 mm/min and 50 mm/min according to IEC 60352-5. Press-in tool designs are available from Interplex. Note that during the press-in process the placement area of the printed circuit board and that of the pressure plate must be parallel to each other. To press a connector onto a printed circuit board a maximum force of up to 550N must be budgeted during press operation. The press-in forces may vary depending on diameter and finish of the plated thru hole in the printed circuit board.
Placement of SMT Version (E-IPX30035 & E-IPX30055)
SMT BusMate® connectors are packaged in EIA industry standard Tape & Reel on a 15” (380mm) reel with 520 BusMate® components per reel. These are compatible with any pick and place machines intended for SMT assembly. For efficient pick and place it is recommended to utilize a custom vacuum nozzle tip. Nozzle tip design and 3D model is available from Interplex.
When inserting the busbar into one or multiple BusMate® connectors in an application, it is important that the assembly be supported to withstand the insertion force of the BusMate®. Interplex’s Floating Contact Technology compensates so that force does not vary depending on any misalignment of the busbar to the BusMate® within the allowed specifications below.
Busbar Installation Force
IPX30013 & IPX 30035 – 9 Lam
Approximately 80N for .8mm Busbar
Approximately 180N for 1mm Busbar
IPX30055 -14 Lam
Approximately 100N for .8mm Busbar
While designed to meet the rigorous requirements of the automotive sector, Interplex BusMate® technology also provides applicability across a broad range of power connectivity requirements in various other industry segments.
In addition to on-vehicle power applications, BusMate® is ideal for use in advanced EV charging station designs where its compact size, configuration flexibility and power density characteristics meet performance requirements, and its ease-of-manufacturability advantages enable high volume production.
Other applications include smaller eMobility products such as eBikes as well as the emerging requirements of Urban Air Mobility (UAM) platforms. Here again, BusMate®’s combination of small size, light weight, high power density and volume production characteristics will mesh effectively with the requirements of these markets.
BusMate® pluggable power connector technology is designed to ensure a low and stable contact resistance while allowing for a wide positional tolerance of the mating blade in all three axes. It achieves this through a proprietary design of multiple floating contacts that adjust to the mating blade while maintaining optimal contact physics and beam mechanics.
BusMate® connectors are subjected to various performance tests based on SAE/USCAR2-6, GMW3191, VW75174 specifications and other rigorous performance standards for automotive applications. They are available with SMT or Press-Fit bases for PCB applications, and baseless versions for direct coupling between busbars.
This configuration flexibility, combined with compact size, high power density and cost-effective volume manufacturing make BusMate® a logical choice for use across the widening range of power connectivity requirements in both current and emerging application areas.