inverter in Electric Mobility and the Requirements for Connectors
Power Management and Intelligent Power Supply
Battery management systems and power electronics play a key role in electric mobility, as they connect various components within the electric vehicle. The connection function within the inverter is handled by the connectors. These are required to control and transmit signals, data, and high currents reliably, safely, quickly, and without loss, despite the demanding operating conditions. To this end, the connector must meet certain requirements in terms of temperature resistance, compactness, and flexibility, as well as performance and robustness.
Background: The Shift to E-Mobility
In recent years, the automotive industry has seen a shift toward e-mobility.
This shift is evident in the increased production of electric vehicles (EVs), rising sales figures, and the expansion of the charging infrastructure for electric vehicles. Consumer demand for more sustainable transportation options is growing steadily. Likewise, significant investments have been made in battery technology to achieve advancements in the range, performance, and cost of electric vehicles. Government incentives for EV adoption, automakers’ commitments to phase out the internal combustion engine, and stricter emissions regulations continue to drive the shift toward electric mobility.
As a result, traditional automakers are increasing their production of electric vehicles.
This shift is evident in the increased production of electric vehicles (EVs), rising sales figures, and the expansion of the charging infrastructure for electric vehicles. Consumer demand for more sustainable transportation options is growing steadily. Likewise, significant investments have been made in battery technology to achieve advancements in the range, performance, and cost of electric vehicles. Government incentives for EV adoption, automakers’ commitments to phase out the internal combustion engine, and stricter emissions regulations continue to drive the shift toward electric mobility.
As a result, traditional automakers are increasing their production of electric vehicles.
inverter in electric vehicles
inverter in electric vehicles are responsible for intelligent power supply and energy management. They connect the electric vehicle’s battery to the vehicle’s electrical loads and, during the charging process, also to the public power grid. This requires different voltage levels.
Two main types of inverter are used in electric cars: DC/DC-inverter and AC/DC-inverter. DC/DC-inverter convert the voltage of direct current. AC/DC inverter convert direct current to alternating current or vice versa. inverter thus convert electrical energy to the voltage level and waveform required by each load to ensure optimal performance.
In electric vehicles, inverter therefore ensure efficient power transfer between the battery and the electric motor to maximize range. Furthermore, Inverters must perform various protective functions to safeguard the electric vehicle and its components against overload, overvoltage, and overheating. Overall, inverter help ensure that the electric vehicle operates safely, efficiently, and reliably while delivering high performance.
Two main types of inverter are used in electric cars: DC/DC-inverter and AC/DC-inverter. DC/DC-inverter convert the voltage of direct current. AC/DC inverter convert direct current to alternating current or vice versa. inverter thus convert electrical energy to the voltage level and waveform required by each load to ensure optimal performance.
In electric vehicles, inverter therefore ensure efficient power transfer between the battery and the electric motor to maximize range. Furthermore, Inverters must perform various protective functions to safeguard the electric vehicle and its components against overload, overvoltage, and overheating. Overall, inverter help ensure that the electric vehicle operates safely, efficiently, and reliably while delivering high performance.
inverter Requirements
inverter must meet a wide range of requirements. These include compatibility, integrability, and efficiency. This means that inverter must be compatible with other systems in the electric vehicle, such as the battery, electric motor, and control unit. In addition, inverter must be easy to integrate in order to simplify the assembly of the electric vehicle and save time and costs. Furthermore, high efficiency is essential to enable long ranges.
Reliability, cost-effectiveness, and overload protection must also be ensured. Reliable operation is necessary to guarantee stable performance for safe and uninterrupted driving. inverter must be affordable to meet the economic requirements of the electric vehicle. inverter must also be equipped with overload protection to prevent overloads and overvoltage and to protect the electric vehicle and its components.
In terms of technical requirements, temperature resistance, compactness, performance, and robustness play a central role. Thus, inverter must:
Reliability, cost-effectiveness, and overload protection must also be ensured. Reliable operation is necessary to guarantee stable performance for safe and uninterrupted driving. inverter must be affordable to meet the economic requirements of the electric vehicle. inverter must also be equipped with overload protection to prevent overloads and overvoltage and to protect the electric vehicle and its components.
In terms of technical requirements, temperature resistance, compactness, performance, and robustness play a central role. Thus, inverter must:
- function reliably across a wide temperature range to be suitable for use
- in a vehicle be compact and lightweight, as any additional weight reduces the range of an electric vehicle
- demonstrate high performance in power and data transmission to meet the needs of the
- electric motor and other systems be resistant to environmental influences, shock and vibration, both during installation and assembly as well as during automated joining and in operation.
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Requirements for Connectors in the inverter
inverter connects the various components in the vehicle, such as the battery storage system to the electric motor. In this context, the inverter must meet the requirements listed above to reliably transmit data and currents in real time. The connectors are responsible for
the connection between the printed circuit boards within the inverter. connector are designed to transmit signals, data, and currents reliably, safely, quickly, and without loss, despite the demanding environmental conditions. Consequently, comparable quality requirements apply to these connectors.
the connection between the printed circuit boards within the inverter. connector are designed to transmit signals, data, and currents reliably, safely, quickly, and without loss, despite the demanding environmental conditions. Consequently, comparable quality requirements apply to these connectors.
Temperature resistance
The materials used in the connector must withstand high temperatures, as required by automotive operating conditions. When selecting the right connector, a wide variety of plastic materials are available for the insulator. However, LCP (Liquid Crystal Polymers) exhibits particularly excellent properties in this context. An LCP-insulator impresses with exceptional dimensional and thermal stability, high stiffness—even in thin-walled components—and a low linear coefficient of thermal expansion. The UL 94 V-0 flammability rating results in operating temperatures for connectors with LCP insulators ranging from -55°C to +125°C.
Compactness and flexibility
Connectors (connector) with a small pitch (pitch) are very well suited for use in inverter, as they are space-saving, require only a small amount of installation space on the printed circuit board, and thus meet the requirement for compactness. Systems with a pitch of 1.27 mm, 0.8 mm, or 0.5 mm, for example, are used for this purpose. However, connectors should not only be small but also adaptable to a wide variety of requirements. This applies, for example, to the required heights, number of positions, or PCB layouts. With connectors such as the One27 from ept, the wide variety of types enables the connection of PCBs in parallel, horizontal, or right-angle configurations, as well as the connection of ribbon cables to the PCB.
The right contact system:
The One27 from ept enables the seamless implementation of horizontal board-to-board distances ranging from 8 mm to 20 mm. This is made possible by the design of the mating face, which features a 2.4 mm contact wipe. By using a cable connection, tolerances in all directions can be compensated for depending on the application, and individually required board-to-board distances can be achieved.
For more information about the product, click here:
One27 »
The One27 from ept enables the seamless implementation of horizontal board-to-board distances ranging from 8 mm to 20 mm. This is made possible by the design of the mating face, which features a 2.4 mm contact wipe. By using a cable connection, tolerances in all directions can be compensated for depending on the application, and individually required board-to-board distances can be achieved.
For more information about the product, click here:
One27 »
Performance
Good signal integrity properties—which ensure the quality of data transmission from the transmitter to the receiver—as well as signal protection are essential requirements for use in inverters. This is because the data transmitted by the connector enables the inverter to intelligently transmit data in real time to the connected loads. The quality of data transmission depends on three criteria:
- impedance profile: As soon as the impedance changes along the transmission path, the signal is reflected, which degrades the quality of data transmission. Even a change in material or geometry can cause the impedance to fluctuate. insertion loss
- (insertion loss): This parameter helps determine whether the receiver can unambiguously identify a signal across the entire transmission path. If a typical insertion loss value of -3 dB is used as a criterion for the data rate of the Zero8 connector from ept (SMT-connector with a 0.8 mm pitch and ScaleX technology), this results in a data rate rate of at least 16 Gbit/s at 8 GHz. crosstalk
- in signal transmission: crosstalk is the unwanted crosstalk of one signal by a signal on another line; depending on the type of interference, a distinction is made between near-end and far-end crosstalk. The severity of crosstalk depends largely on the signal and ground assignments.
The signal integrity characteristics of a connector can be significantly improved through EMC-Schutz (electromagnetic compatibility). Electromagnetic compatibility refers to the ability of a technical device not to be disrupted by—or to disrupt others due to—intended or unintended electrical or electromagnetic effects. Electromagnetic interference in connectors can be reduced through a shielding design. The coupling inductance (mutual inductance) simulates the connector (connector) acting as both a source of interference and a sink for interference. The effect of the shielding design can be clearly seen in the following figure based on the color gradients and the values of the coupling inductance.
By using the shielded Zero8 connector, noise sources and sinks on the printed circuit board can be positioned closer together, and the electrical device can achieve higher performance ratings in the required burst and surge tests.
In addition to signal integrity characteristics, a connector’s current-carrying capacity (current-carrying capacity) for power transmission is also a key area of expertise. Current-upper limiting temperature curves can be used to determine how much current may be passed through a contact at a given ambient temperature without exceeding the component’s maximum allowable temperature limit. The following derating curve illustrates, for example, how the Zero8 connector yields different current ratings per contact depending on the number of positions and the number of current-carrying contacts.
As shown in the figure, a 12-pin connector (blue curve) achieves better current-carrying capacity compared to an 80-pin connector (green curve). The reason for this is reduced hotspot formation inside connectors with a lower number of number of positions: less heat is generated here, and it can be distributed more effectively. Heat is dissipated even more effectively when the current flows through only a small portion of the contacts (red curve).
As shown in the figure, a 12-pin connector (blue curve) achieves better current-carrying capacity compared to an 80-pin connector (green curve). The reason for this is reduced hotspot formation inside connectors with a lower number of number of positions: less heat is generated here, and it can be distributed more effectively. Heat is dissipated even more effectively when the current flows through only a small portion of the contacts (red curve).
Robustness
In the case of SMT-Steckverbindern, the robustness of a connector is evident, for example, in the design of the contact mechanism between the blade and Female with dual contacts, the quality of the contact plating to minimize surface abrasion, or the SMT leads, which must be designed for optimal fillet formation. When processing and handling SMT-connector, it is also important that they be as robust as possible. During the mating process itself, lead-in chamfers and a generously dimensioned gathering range (retention area) allow for a high degree of tolerance compensation and serve to make handling the connectors as easy as possible.
Connectors are exposed to high levels of shock and vibration in an inverter, as they are typically mounted close to the motor. Shock and vibration jeopardize the constant and interference-free contact between the printed circuit board and the connector, as well as between connector themselves. Reliable and durable contact between a connector and the printed circuit board can be achieved, for example, through the press-fit technology. The goal of the press-fit technology is to achieve the highest possible retention forces between the connector and the printed circuit board. This is because the retention forces determine the mechanical connection, which in turn must withstand shock and vibration. This connection technology (termination technology) is a proven process in which a press-fit pin (press-fit pin) is pressed into a PCB hole; mechanical deformation of the pin creates a gas-tight, corrosion-free, low-resistance, and electrically safe mechanical connection that is also suitable for potting (potting). ept GmbH offers both standard products and custom solutions utilizing this manufacturing technique.
In this process, the press-fit pin has a larger diagonal dimension than the PCB hole diameter. The connector pin is flexible within the press-fit zone to ensure that the PCB is not deformed or damaged by the physical forces during the press-fit process. The deformation is thus limited to the press-fit zone. During the press-fit process, a cold welding forms between the contact pin and the metallized PCB hole, making the connection mechanically robust without subjecting the PCB to thermal stress from a soldering process. It is also specified in DIN EN 60352-5 and maintains a secure connection even under very high mechanical and thermal stresses—such as vibration, bending, and extreme temperature fluctuations—while withstanding shock loads of up to 200g. Thanks to the press-fit technology (press-fit technology), the Flexilink connector from ept is distinguished by special quality features:
In this process, the press-fit pin has a larger diagonal dimension than the PCB hole diameter. The connector pin is flexible within the press-fit zone to ensure that the PCB is not deformed or damaged by the physical forces during the press-fit process. The deformation is thus limited to the press-fit zone. During the press-fit process, a cold welding forms between the contact pin and the metallized PCB hole, making the connection mechanically robust without subjecting the PCB to thermal stress from a soldering process. It is also specified in DIN EN 60352-5 and maintains a secure connection even under very high mechanical and thermal stresses—such as vibration, bending, and extreme temperature fluctuations—while withstanding shock loads of up to 200g. Thanks to the press-fit technology (press-fit technology), the Flexilink connector from ept is distinguished by special quality features:
- Minimal nozzle effect (i.e., deformation of the trace)
- Prevention of cold solder joints and short circuits caused by solder bridges
- High strength and robustness combined with excellent spring characteristics
- Process-reliable manufacturability through optimal adaptation to the processing technology
- Reliable reproducibility in manufacturing through embossed shaping
- Meets the highest requirements of leading manufacturers in automotive electronics
- Highest reliability and failure resistance—proven billions of times over
Would you like to gain even more in-depth technical knowledge about press-fit technology?
For comprehensive details on the fundamentals of press-fit technology, we’d be happy to send you our free white paper:
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For comprehensive details on the fundamentals of press-fit technology, we’d be happy to send you our free white paper:
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Any questions?
Then please contact us!
Submit an inquiry via the form
+1 (806) 304-0402
sales@eptusa.com
Then please contact us!
Submit an inquiry via the form
+1 (806) 304-0402
sales@eptusa.com