An on-board charger (OBC) is a device mounted inside the electric vehicle that converts AC power from an AC source into practical DC form, and its primary function is power conversion. This allows electric vehicles to be charged using the power outlets in our homes, eliminating the need to purchase additional equipment for power conversion. In this blog, let’s look at how on-board chargers are an integral part of EVs and Amphenol’s flex-to-board, power, and wire-to-board connector solutions for on-board chargers.

What are On-board Chargers?

On-board EV chargers/dischargers are those placed inside the EV. Unlike off-board, on-board ones provide the flexibility of charging with an accurate voltage matching for the EV battery through any electric outlet available. The battery voltages in EVs vary from vehicle-to-vehicle whereas the grid voltage is generally fixed. EV manufacturers precisely make the on-board charging systems to distinct voltage requirements whereas off-board systems support a wide range. Although the presence of an on-board charger can alter the weight, volume, and price of the EV, these chargers facilitate fast charging/discharging with high power dense converter systems.

On-board systems have the advantage of simplifying the charging/discharging infrastructure requirements that reduce the cost of off-board outlets.

Role of On-board Chargers

The primary function of an on-board charger is to manage the flow of current from the grid to the traction battery, enabling electric vehicles to be charged from any source without relying solely on charging stations.

The OBC also plays a crucial role in controlling the level of current and voltage used to charge the battery, with two primary charging methods: constant voltage and constant current charging. While constant current charging provides high efficiency and charging speed, it can potentially reduce the lifespan of the battery due to over-charging. Conversely, with constant voltage charging, there is a risk of a high amount of initial current flowing into the battery.

To address these issues, a two-step charging method is typically performed, starting with constant current charging initially and then transitioning to constant voltage charging once a certain amplitude is reached. This charging method is a critical function of the on-board charger.

Amphenol’s On-board EV Charger Connectors

Amphenol offers flex-to-board, power, and wire-to-board solutions for On-Board Chargers (OBCs) that form a crucial component of EVs. In the range of Battery Management Systems (BMS), Amphenol's solutions ensure safe and efficient charging of EVs at home.

FlexFast

The FlexFast™ Flex-to-Board connector has a compact design that meets the increasing demands for flex-to-board solutions in automotive applications. It is compliant with USCAR T3V2 and LV-214 S1 specifications and features gold-plated terminals to reduce mating force. The connector has a low mating and un-mating force, a maximum height of 8.0mm, and is space-saving. It also features CPA (Connector Position Assurance) and FPA (Flex Position Assurance) to ensure proper mating and flex insertion retention. Additionally, the double beams and contacts provide better vibration and contact performance.

The FloatCombo™ is a floating board-to-board solution specifically designed for devices with large current and space-saving requirements. It features up to 4 independent power pins supporting 5A current per pin and provides a high-speed transmission performance of up to 16Gb/s. The FlexLock™ with its compact FPC-to-Board connector performs to both USCAR-T2V2 and LV-214 S3 specifications. WireLock® is a 1.80mm pitch wire-to-board and flex-to-wire connector system. Its compact design addresses the growing need for space-saving automotive-grade connectors. The 0.5mm and 2.00mm pitch Autolock Non-ZIF FFC connectors feature an auto-lock mechanism. When coupled with FFC cable assembly, the solutions provide robust performance in high-temperature and vibration environments, with space savings, cost savings, and ease of operation.

Click here to explore more of Amphenol’s on-board charging solutions.