MEAN WELL: One Technology for Multiple Applications – Bidirectional Power Supply in Use

Figure 1: The bidirectional BIC-5K power supply from MEAN WELL ensures efficient energy conversion. (Source: MEAN WELL

Why is bidirectional energy transfer becoming increasingly important?

With the continuous expansion of renewable energy and e-mobility, the demand for intelligent energy storage is growing—systems that can flexibly transfer energy in both directions, from the grid to the device and back. This is where bidirectional power supplies come into play: they feed surplus energy, for example from wind and solar systems, back into the grid and draw it again when needed (Fig. 2). In doing so, they help compensate for grid fluctuations, reduce peak loads, and enable the targeted use of renewable energy, while also lowering electricity costs in home energy storage systems and industrial applications. In the electric vehicle sector, bidirectional charging stations open up additional possibilities: vehicle batteries can not only be charged but also used as mobile power sources or for feeding energy back into the grid.

Figure 2: The BIC-5K controls the bidirectional energy flow between the AC grid and renewable energy sources as well as DC applications, including battery storage, V2G/G2V, and DC loads. (Source: MEAN WELL)

How is efficient bidirectional energy conversion achieved?

The operation of battery systems involves three core tasks: charging, storing, and discharging. To ensure the most efficient energy conversion possible, devices with a high conversion efficiency are required. This is exactly where the MEAN WELL BIC-5K comes into play: as a bidirectional power supply, it combines a charger and an inverter in a single unit, acting both as a power source and a load. This reduces costs and significantly minimizes space requirements in the application. Specifically, the bidirectional power supply is characterized by high efficiency, intelligence, compact size, and comprehensive safety certifications:

• High efficiency: With an efficiency of up to 93%, the BIC-5K converts DC to AC and vice versa. It also offers a THD (Total Harmonic Distortion) of < 3% in both conversion modes.
• Ultra-fast switching time: AC/DC and DC/AC switching in just 1 ms.
• Flexible use: Supports three-phase systems and parallel operation of multiple units.
• Scalable power: Parallel operation up to 30 kW system output for high power demands.
• Compact design: Digital 5 kW power supply with energy recycling in a low-profile 2U design.
• Comprehensive protection: Wide range of applications thanks to multiple protection functions, including anti-islanding, AC failure, DC OVP, OLP, OCP, and OTP.

How do bidirectional power supplies improve battery production?

Bidirectional power supplies are used across numerous industries. In the battery sector in particular, the BIC-5K is widely utilized thanks to its comprehensive safety features. During the development and production of lithium batteries, multiple charge and discharge cycles are required as part of battery formation and sorting, which involve very high energy consumption. These processes are essential to ensure that each battery meets its specifications. In this application, the BIC-5K charges the batteries and, during discharge, feeds energy back into the grid, thereby reducing costs and CO₂ emissions. Bidirectional power supplies are also becoming increasingly important in lithium battery recycling, especially for automotive batteries. Before disassembly, the battery voltage must be reduced below a safe level to prevent fires or explosions. The BIC-5K safely discharges the battery and feeds the released energy back into the power grid, where it can be used by other AC loads (Fig. 3).