With the continuous growth of new energy demand and the transformation of energy structure, the market scale of energy storage technology continues to expand. As an important part of the battery module in the energy storage system, the energy storage PCB plays a key role in the safety and performance of the entire system. In this article, we will share some guidelines for design and manufacture energy storage PCB.
What is energy storage?
Energy storage refers to the storage of energy, which refers to the process of storing energy through media or equipment and releasing it when needed.
Upstream and downstream products of the energy storage industry
It can be found that the upstream industry is mainly based on materials and related system equipment, while the midstream industry is mainly based on energy storage installation systems and integrated systems. For the midstream industry, it is closely related with PCB industry. In addition, there are various downstream application-level products, such as photovoltaic products, charging pile products, etc.
Take the lithium battery and photovoltaic as an example, because various control systems, such as battery management system(BMS), photovoltaic inverter, and lithium battery charging pile products, all of them cannot normal work without PCB boards.
What are the characteristics of the energy storage PCB?
1.BGA chips and some fine-pitch devices are not easy to find on energy storage PCB boards. Because energy storage PCB is mainly for charging and discharging function.
2. The energy storage board generally has thicker copper which generally are above 2oz. And it is mainly used for high current with high voltage (up to kilovolts).
3. It is also because the board is more prone to heating issues due to the operation of high current, so the energy storage PCB board is usually treated for heat dissipation, such as drilling heat dissipation holes or adding some packaging heat dissipation shells, etc.
Factors should be considered during design and manufacture energy storage PCB
Firstly, due to the existence of large current, the power ground will be disturbed when the large current flows. Secondly, EMC interference radiation is easily generated during the change of the large current.
Therefore, we should pay attention to the following points when designing and manufacturing energy storage PCBs:
1.Choose high-performance materials suitable for high-current demands as much as possible, such as FR-4, metal substrates, and composite materials. These materials have low resistance, high thermal conductivity and good mechanical strength, which can withstand large currents under heat and current concentration effects.
2.The current distribution is balanced. Reasonable current distribution can reduce the resistance and hot spots of the current path. For example, adding a balance current device, balance resistance or current balance layer can improve the reliability and stability of the circuit board.
3. When designing PCB wires, try not to cross the high current path and the digital signal to avoid mutual interference.
4.The high-current path should be treated with solid copper as much as possible. First, the current carrying capacity is relatively large. Second, it will have a better heat dissipation effect. Third, avoid large trace impedance and large voltage drop on the trace.
5.The heat generated by high current will damage the device and the product, so the power path should be paid more attention to. Generally, a large area of copper is laid, holes are drilled, and the external resistance soldering layer is dug out to expose the copper to speed up heat dissipation.
6. The EMC radiation problem of large currents should be considered during the layout. Methods such as thickening the line width, increasing the aperture and the spacing can be considered to adopt. Keep the high current path as short as possible, and place it away from easily interfered devices (signal interference and thermal influence) when planning the path on the circuit board.
What are the challenges of energy storage PCB manufacturing?
Because of the influence of high current, thick copper plates are generally required. Here are some processing difficulties of thick copper plates as follows.
1. Difficulties in etching
Because of the increase of copper thickness, it is more difficult to exchange the potion. In order to reduce the amount of side erosion caused by the exchange of potion as much as possible, multiple rapid etching is required. As the amount of side erosion increases, it is also necessary to compensate for the side erosion by increasing the etching compensation coefficient.
2. Difficulties in lamination
With the increase of copper thickness, the line gap is deeper, and the required amount of resin filling needs to be increased accordingly. Since the resin needs to be used to fill the line gap and other parts to the maximum extent, the prepreg with high glue content and good resin fluidity is the first choice for thick copper plates. However, the increase in the use of prepreg will also increase the risk of sliding boards. It is common to use the method of adding rivets to strengthen the degree of fixation between the core boards.
3. Difficulties in drilling
Thick copper plates usually have a thickness of more than 2.0mm. When drilling, X-RAY’s energy gradually decays with the increase of copper thickness, and its penetration ability will reach the upper limit. In addition, the problem of cracking the pad when drilling the PCB is also commonly occurred.
The solution for this difficulty is to increase the pad and the peeling strength of the material and reduce the cutting speed of the drilling hole.
Conclusion
IBE has more than 19 years of experienced in PCB and PCB assembly industry. We are dedicated to improving our manufacturing process capabilities, which can meet the various needs of customers for products. Energy storage PCB related business can be processed as well.
Currently, we have four factories in China, Vietnam and the USA. We are capable of handing mass production demands and better shorten the delivery time.
Energy storage refers to the storage of energy, which refers to the process of storing energy through media or equipment and releasing it when needed.
1. High power and high temperature characteristics
2. Large current carrying capacity
3. High reliability and safety
4. High density and complexity
5. Long life cycle
- High Environmental requirements
- Material selection
- Welding process
- Details processing like the direction, position, and spacing of the components.
- Quality control
