A guide to PCB materials used in EV manufacturing

The automotive industry is gradually moving on from mechanical to electrical power, which presents new opportunities for developing better and more sustainable vehicles for travel. However, these new opportunities also present challenges that require resolution to ensure that future electric vehicles will work as planned and be safe for passengers to use.

But that won’t be possible without the right materials to create the key components that can elevate the driving experience in an EV while keeping it safe. In this article, we’ll explore the role of PCBs inside electric vehicles and also cover a guide regarding some of the notable PCB materials and technology that see a lot of use in electric vehicle manufacturing.

Role of PCB inside Electric Vehicles

Before we delve deeper into this discussion and cover our focus topic, the PCB materials and technology used in electric vehicle manufacturing, let’s talk about the roles PCBs fulfill in EVs first. The best way to sum up the role of a PCB inside electric vehicles is if the battery pack is the heart of the EV; the PCB functions as the brain of the vehicle, regulating its functions.

Here are some of the roles or functions that an EV’s PCB fulfils once it is integrated inside the vehicle:

1. Monitors Individual Cell Voltage

PCBs integrated into the electric vehicle’s battery management system are responsible for checking the voltage levels of every cell within the battery pack. Through individual monitoring, voltage levels inside the cells will be regulated, and there won’t be one or more cells that are overcharged or over-discharged, thus preventing any detrimental effects on the battery’s health and safety.

2. Prevents Excessively Low or High Voltages to Individual Cells

Integrating a dedicated PCB on the BMS can help prevent overcharging or overdischarging, wherein an individual cell or more reaches extremely low or high voltages, which can be perilous to the health of the EV’s battery pack. Whenever the BMS PCB detects these abnormal voltage spikes or drops inside a cell in the battery pack, it activates a protection mechanism that prevents potential battery damage.

3. Temperature Regulation

The BMS PCB also plays a significant role in maintaining the temperature of the EV’s battery pack, and if the PCB perceives the battery pack is about to overheat, it will do one of the two cooling mechanisms. It will either activate a cooling system to lower the temperature or cut off discharging or charging if it perceives that the battery temperature is dangerously high.

4. Balanced Power Distribution

The BMS PCB also plays a pivotal role in balancing power distribution, especially if the EV is integrated to contain multi-cell battery packs in which each cell has a distinct capacity or performance quality. Power balancing is done by managing the distribution of charge or discharging currents and ensuring that all cells are utilized evenly.

• Aside from power balancing, PCBs inside an electric vehicle also facilitate protection against overcurrent. The PCB integrated into the BMS can monitor the current flowing in and out of the battery pack. If the current is too strong, it will trigger a protective mechanism to mitigate damage.

• BMS PCBs also play a key role in preventing short circuits. The moment they detect short circuits within the battery pack, they deploy their emergency protection protocols to prevent damage to cells and surrounding critical components.

• Speaking of power, a BMS PCB can communicate with its user through a “state of charge” estimation. In combination with a viewing module, the BMS PCB will use an algorithm that broadcasts the current charge levels of the battery pack, thus allowing drivers to know how much charge is left inside the vehicle before it needs recharging.

5. Communication with Other Components

As mentioned earlier, the BMS PCB assumes a supervisory role in the electric vehicle’s daily functions, such as managing the battery management system. But how is this done? By adding a communication interface such as UART and CAN bus, the PCB can relay information to other critical components inside the vehicle – for example, it can relay battery charge information on the user interface to notify the driver of the EV’s current battery levels.

In other words, a PCB integrated inside an EV will communicate with other critical components to maintain functionality during use and may relay information to the driver while on the road.

6. Emergency Shutdown

Should the electric vehicle’s battery pack sustain severe damage or be in a state of emergency, the BMS PCB can commence an emergency shutdown to sever the battery pack from the charger or the load, thus averting any potential accidents such as an explosion.

Prominent PCB Materials and Technology used in Electric Vehicle Manufacturing

Now that we’re oriented on the roles that BMS PCB plays inside electric vehicles, let’s move to our main topic, which is prominent PCB materials and technology used in EV manufacturing. Why mention these technologies and materials? They are pivotal in ensuring the functionality of the electric vehicle, making for a great driving experience without worries.

Here are some of the most known PCB materials and pieces of technology used in electric vehicle manufacturing according to e-motec Magazine and Altium:

1. Power Combi-Boards

The first featured PCB material we’ll cover is the Power Combi boards. These materials come into play when heavy copper PCBs can’t work with the fine pitch structures that can’t be etched with the copper material mentioned.

That’s because, unlike heavy copper PCBs, a Power Combi board offers the same perks and space it provides but without the restriction of etching fine pitch structures onto its surface. However, heavy copper is still used in this PCB material to increase its compatibility with the surface mounting of components added to the material’s inner layers.

2. Insulated Metal Substrates

If overheating concerns electric vehicles, then the IMS or insulated metal substrates should do the trick in thermal management. These substrates comprise a metal heat sink, a single copper layer on the top, and a papery insulation layer. The IMS is useful for simple mechanical designs that emit a lot of heat due to its components.

However, routing with one layer won’t be feasible if you are working with more complex designs such as electric vehicles. You’ll have to work with multilayer IMS substrates if you want them to be compatible with complex setups that require proper thermal management.

3. Heavy Copper Printed Circuit Boards (PCBs)

Heavy copper PCBs have historically been used extensively in the automotive industry, where their main role tends to be inside fuse or relay boxes. However, that has changed recently, as the resurgence of heavy copper PCBs is starting to see usage in electric vehicles, where they act as a regulator of electrical flow inside them.

Ideally, heavy copper is useful in preventing or reducing the parasitic inductance of the conductors by using the heavy copper layers as power lines stacked on top of one another – thus preventing parasitic inductance, which negatively affects the electric vehicle’s performance.

4. Inlay Technology

Inlay technology is excellent for PCBs that are used in electric vehicles as it also addresses thermal management issues. The usual setup for inlays within PCBs is that the heat has to be dissipated from the Z-axis of the PCB’s assembled top side. The route that the heat within the PCB takes is through the PCB board won to a heat sink at the bottom, where it is eventually released.

Thus, using inlay technology is key to addressing thermal management issues and preventing the overheating of the EV or its key components.

5. Embedding Technology

Since PCBs are starting to become smaller and smaller, embedding technology is increasing in value, especially in automotive applications and EVs. Utilizing embedding technology gives you the power to install key components for your EV’s printed circuit boards, even on small board spaces.

Embedding has become even better since the concept of installing components inside the PCB has become a thing, leading to even more compact and EV-compatible PCBs.

6. Ceramic PCBs

Ceramic printed circuit boards are also gaining a positive reputation in automotive applications, particularly electric vehicles. That’s because Ceramic PCBs enjoy the advantages of having excellent thermal management, durability, and reliability for their value. To give you a clue how good ceramic PCBs can conduct heat; compared to a standard FR-4 board, ceramic PCBs are more than a hundred times conductive.

Ceramic PCBs are a welcome addition to any EV application due to their miniaturization options and excellent signal transmission in high frequencies. It may come in with some cost considerations; but compared to dealing with a total power failure, it is tame in comparison.

7. Glass-reinforced PTFE

Last but not least, we’ll cover Glass-reinforced PTFEs, which are PCB materials that manufacturers love for their safety and control, but also because it is used in LED headlights of vehicles which emit a lot of heat but are not favourable for ceramic PCBs. These glass-reinforced PTFEs are known for utilizing a layered manufacturing process that offers better thermal stability, which is reminiscent of standard resin boards but better.

Each PCB Material Plays a Role in Safe Electric Vehicles

To sum up what we’ve covered – PCB materials are quintessential in ensuring the safety and consistency of electric vehicles. Each of the materials we’ve covered has its set of perks and characteristics that make it fit for the job. From regulating temperatures to linking up with other key components, these PCB materials have made it possible for us to enter a new age of the automotive industry where electric energy will power our vehicles.

Author credit

Ross Feng, a PCB industry expert with 16+ years of experience at Viasion Technology Co. Ltd, is a tech-savvy professional known for innovation. His expertise has been crucial in shaping electronic design. Ross, driven by a passion for excellence, continues to contribute significantly to the dynamic world of PCB technology.

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