Read this article: High-power connectors in energy storage systems

The reason why an energy storage system is introduced is determined by the characteristics of the power grid. First of all, the amount of power generated in the power system is continuous, while the amount of electricity consumed varies from high to low. This mismatch between supply and demand is often a major cause of unnecessary energy loss.

Secondly, in today’s power system, the proportion of renewable energy sources such as solar energy and wind energy is increasing. However, these greener energy sources are subject to environmental influences and have the disadvantages of being intermittent and discontinuous. In the case of renewable energy power generation, By adding an energy storage system between the power supply side and the grid side, it can be adjusted and buffered to achieve smooth output and ensure the stability of power supply.

In addition, another benefit of the energy storage system is that when the main grid cannot supply normal power due to faults and other reasons, it can function as a large "power bank" to provide emergency backup power.

It is not difficult to see that the deployment of energy storage systems can significantly improve energy utilization efficiency and user experience on the power generation side, grid side and user side of the entire power system.

Table 1: The role of energy storage systems

It is precisely because of these unique functions of energy storage systems that in recent years, with the development of new energy, its development has entered a period of rapid growth. According to research data from the China Photovoltaic Industry Association (CPIA), the new installed capacity of new energy storage in the world and China in 2022 will be approximately 32GWh and 7GWh respectively. By 2025, this data is expected to quickly climb to 75GWhh and 21GWh. In the industrial field, this growth rate is quite eye-catching.

Among new energy storage devices, electrical energy storage systems based on electrochemical batteries (mainly lithium-ion batteries) occupy a dominant position. The electric energy storage system mainly consists of a battery pack, a battery management system (BMS) and a power conversion system (PCS). The PCS is mainly responsible for injecting electric energy into the battery, DC charging the battery, and converting the energy stored in the battery into alternating current. The function of BMS is to monitor and intelligently manage the status of the battery pack to ensure reliable, safe and long-term operation of the battery pack.

In the entire energy storage system, all energy transmission is inseparable from a key component, which is high-power interconnection components, such as busbars/busbar connectors. They must not only carry high-voltage and high-current energy, but also ensure Safe and reliable work is crucial.

Specifically, ideal high-power connectors in energy storage systems need to have the following characteristics:

For energy storage system interconnection design requirements, Molex can provide a series of high-current, high-voltage power connector solutions. They all have a common feature, which is the use of Molex's unique COEUR socket technology. As can be seen from Figure 1 , the COEUR socket has multiple contact beams, which can form a larger contact surface at the mating interface, thereby achieving low contact resistance and voltage drop, greatly reducing heating and power loss at the contacts, which is very suitable for for high power applications.

Figure 1: COEUR socket technology

(Image source: Molex)

On the basis of fully considering the high-power and high-reliability connection requirements, Molex also introduces different innovative technologies in connector design according to specific application scenarios to obtain better overall performance. Below, we will give you a panoramic understanding of Molex's high current and high voltage solutions for energy storage applications through three representative products.

Figure 2: Molex high current and high voltage solution

(Source: Mouser)

Sentrality high-power pins and sockets feature eye-of-the-pin crimp tails for high-quality, solder-free electrical connections. Due to the use of COEUR socket technology, the connector supports a rated voltage of 600V and a rated current of up to 350A. The contact resistance is only 0.40mΩ. It also has 200 mating and unplugging times and a temperature range of -40°C to +125°C . It can Meet the application requirements of energy storage systems.

Figure 3: Sentrality high power pins and sockets

(Image source: Molex)

There are inherent tolerance stacking issues in any mechanical design, and the challenges this brings are even more prominent when connecting high-power power supplies. To address this challenge, Sentrality connectors feature Molex’s proprietary OmniGlide technology, which provides up to +/-1.00mm of radial self-alignment, significantly reducing stress on the connector (especially the receptacle contact beam) during the mating process. potential damage.

Figure 4: Sentrality supports +/-1.00mm radial self-alignment

(Image source: Molex)

In terms of compact design, the height of Sentrality connector is only 10mm, which can provide more space for design. Due to the uniform flat-top surface design, the Sentrality connector can be tilted when inserted into the PCB, achieving greater convenience.

In addition, Sentrality pins and sockets offer a variety of board connection options, suitable for PCB or busbar, and can be customized for specific applications, providing sufficient flexibility for design and manufacturing.

Figure 5: Sentrality offers great flexibility in design and manufacturing

(Image source: Molex)

PowerWize high-current interconnection system is a high-current wire-to-board/wire-to-bus interconnection solution developed by Molex based on COEUR socket technology. It includes two specifications: 6mm and 8mm, which can provide rated current carrying capacities of 120A and 175A respectively.

Figure 6: PowerWize High Current Interconnect System

(Image source: Molex)

To ensure a reliable connection, PowerWize connectors feature side locking on 6mm and top locking on 8mm, and provide tactile and audible feedback to ensure secure mating.

Figure 7: PowerWize provides locking mechanism

(Image source: Molex)

All PowerWize socket headers and receptacles are mechanically keyed to avoid mismating during operation. In addition, the 6mm connectors are color-coded to facilitate the use of multiple connectors simultaneously in one application.

Figure 8: PowerWize provides color coding

(Image source: Molex)

PowerWize connectors are available with crimp contact options for 1AWG, 2AWG, 4AWG, 6AWG, 8AWG and 10AWG wire gauges. The battery-operated accessory (including 120 and 220V options) also supports field contact crimping and field cable assembly construction, suitable for scenarios where the cable assembly length cannot be determined before installation, making it more suitable for applications such as energy storage systems. flexibility.

Figure 9: PowerWize installable area

(Image source: Molex)

SW1 high-current wire-to-board and busbar interconnections also use COEUR sockets to provide strong support for high-power applications. This connector series includes three types of products: 6mm, 8mm and 11mm, corresponding to high current carrying capacities of 120A, 185A and 300A respectively.

Figure 10: SW1 high current wire-to-board and busbar interconnection

(Image source: Molex)

COEUR socket technology also has a compact appearance. Compared with similar solutions using hyperbolic sockets, the design height of the SW1 connector is reduced by about 1/3, and the length is also shortened by about 1/3. The Z-axis mating configuration is conducive to reducing the The small cable bending radius makes it an ideal solution for space-constrained applications.

Figure 11: SW1 connector is ideal for space-constrained applications

(Image source: Molex)

The positive locking stainless steel spring clip of the SW1 connector ensures a secure connection and prevents the cable assembly from falling off due to vibration, impact or mishandling. Positive locking stainless steel spring clips are simple to operate: press to retract and release to engage. Moreover, the stainless steel spring clip is locked on the groove of the locking pin, allowing the cable assembly to rotate 360° around the locking pin, which brings great convenience to the adjustment and maintenance of the cable assembly.

In addition, the SW1 connector receptacle shell is also color-coded to facilitate identification of different cable connections in the same application and prevent mismatching. In short, the SW1 connector has done enough work to improve the "friendliness" and convenience of user operations.

Figure 12: SW1 connector positive locking mechanism

(Image source: Molex)

The deployment and application of new energy has brought the development of energy storage systems into the fast lane, and also allowed high-power power connectors to find a new market space. Higher current carrying capacity, safe and reliable connection, compact appearance, user-friendly experience... This is what people want for ideal high-power connectors for energy storage systems.

Based on this requirement, Molex's series of high current and high voltage power connectors came into our view. Understanding these connectors will make your energy storage system development more efficient.