Invented by PARK; Hye Jin, YU; A Rum, WOO; Myung Heui, YANG; Seung Yong, LEE; Jung Hyo, LEE; Jae Hyun, RA; Ha Na, YANG; Yun Sung, SAMSUNG SDI CO., LTD.

Today, let’s explore a new patent application for a heat insulation sheet designed for rechargeable lithium batteries. This technology is about keeping batteries safer and more stable, especially when they get hot. We’ll look at why this is important, what science and patents came before, and what makes this new invention special. Whether you work with batteries or just want to know more about the tech in your devices and cars, this article will help you understand it in simple words.

Background and Market Context

Rechargeable lithium batteries are everywhere. They are inside your phone, your laptop, and even in electric cars. These batteries help power our world because they can store a lot of energy and last a long time. But as we use more of these batteries in more powerful devices, safety becomes a big concern, especially when batteries get too hot.

When lithium batteries get too hot, they can break or even catch fire. This is called thermal runaway. It can happen if the battery is damaged, overcharged, or if something goes wrong inside. For things like electric cars, where many big batteries are packed close together, this is a serious risk. If one battery cell gets too hot, it can spread heat to the next one, and the problem can quickly get worse.

To solve this, battery makers put materials between cells to stop the heat from spreading. These materials need to block heat but also be soft enough to handle pressure as the batteries swell and shrink during use. This is called heat insulation and compression property. Both are important to keep batteries safe and working well for a long time.

The market for lithium batteries is growing quickly. Electric cars, in particular, need very safe and reliable batteries because people rely on them for daily travel. Any kind of fire or breakdown is not just expensive—it can be dangerous. Makers of cars and battery packs are always looking for better ways to keep their batteries cool and safe. They look for new materials and new designs that can make batteries last longer and work better without getting too hot.

This is where the new heat insulation sheet comes in. It is designed to fit between battery cells and block the heat from spreading, even if one cell gets very hot. It can also handle the pressure when batteries swell or change shape. The goal is to make battery packs safer for everyone, whether they are used in cars, phones, or any other device.

Scientific Rationale and Prior Art

To understand why this new heat insulation sheet matters, let’s talk about the science behind battery heat and the materials used to stop it. When a lithium battery works, it moves lithium ions between two sides, the positive and negative electrodes. This process is safe most of the time. But if too much heat builds up, the battery can get damaged or catch fire.

Over the years, many materials have been used to stop heat from spreading between battery cells. Common materials are plastics, ceramic papers, and even foams. One popular material is called mica. Mica sheets can block heat and are used in many electrical devices. However, while mica is good at stopping heat, it is stiff and can break if pressed too hard.

Another key material is aerogel. Aerogel is a super-light, porous material made from silica or other chemicals. It is often called “frozen smoke” because it is so light and airy. Aerogel is one of the best materials for blocking heat. NASA has even used it to collect space dust! But aerogel is fragile and hard to use by itself in big battery packs. It can also make dust, which is bad for battery health.

To make aerogel stronger, engineers mix it with fibers, like glass wool. This gives the material strength and lets it handle pressure without breaking. Binders, like polyvinyl alcohol or polyurethane, are added to help stick everything together and make the sheet easier to handle and safer to use. These binders can also help block dust from the aerogel.

Prior patents have tried different mixes of these materials. Some use just aerogel and binder, but those can be too weak. Others use fibrous mats with aerogel, but the mix often does not block enough heat or is too stiff. Still others use only mica, but as we saw, mica alone is not flexible.

The main challenge in the field has been to create a sheet that is thin, strong, blocks heat very well, and can handle pressure when batteries swell. The sheet also needs to be easy to make, affordable, and not shed dust, which could damage batteries over time. Many older patents solve one or two of these problems, but not all at once.

So, before this new patent, there was no perfect solution. Sheets made only with mica were tough but not flexible. Sheets with just aerogel were good for heat but fragile. Mixes with fibers and aerogel were better, but often still lacked the right combination of softness, strength, and heat blocking. The need for a better solution was clear, especially as batteries got bigger and more powerful in electric cars and other devices.

Invention Description and Key Innovations

This new patent offers a fresh way to make heat insulation sheets for lithium batteries. Let’s break down what it is and why it stands out.

The sheet is made by stacking different layers on top of each other. The main layers are:

– A first base layer, which is usually a mica sheet. This layer gives support and helps block heat.
– A first aerogel-containing layer. This layer includes aerogel, fibers (like glass wool), and a binder (like polyvinyl alcohol or polyurethane). The fibers make the layer strong and flexible.
– A second aerogel-containing layer. This middle layer has mostly aerogel and a binder, but no fibers. Because it is mostly aerogel, it blocks heat very well.
– A third aerogel-containing layer. This is like the first aerogel layer, with aerogel, fibers, and binder. It adds more strength and flexibility.
– Optionally, a second base layer (also usually mica) can be added on the other side for extra strength.

By stacking these layers in this order, the sheet gets the best of all worlds. The base layers (mica) give support and make the sheet easy to handle. The aerogel layers block heat. The fiber-reinforced aerogel layers at the edges make the sheet strong and able to handle pressure. The middle aerogel-only layer adds even more heat blocking.

This design is special for a few reasons. First, it uses more aerogel in the middle, where heat blocking matters most, but adds fibers to the outer layers for strength. Second, the use of binders helps hold everything together and stops dust from escaping, which can help the batteries last longer. Third, the sheet is soft enough to handle pressure when batteries swell, but strong enough not to break.

The patent also gives details on how much of each material to use. For example, the fiber can be 5% to 70% of the outer aerogel layers. The aerogel in the middle layer can be up to 99%. The binder is added in just the right amount to balance dust control and flexibility. The layers are thin—usually less than a millimeter each—so the sheet fits easily between battery cells.

Another key innovation is how the sheet is made. The materials are mixed into slurries and then coated onto the mica base and dried at low heat. This process is simple and can be done with standard machines, making it cost-effective and easy to scale up for making lots of sheets at once.

In tests, sheets made using this method had better heat insulation and could handle more pressure before breaking compared to older designs. When placed between two hot plates, they kept the cool side cooler for longer. When squeezed, they compressed well without cracking. This means the sheet can help keep batteries safer by blocking heat and handling pressure changes, which is very important in electric cars and other big battery systems.

The sheet can be used in all kinds of battery packs. It fits between the battery cells, keeping each cell safer from its neighbor. This is especially useful in electric cars, where many cells are packed close together. The sheet can also be used in battery packs for bikes, laptops, and other devices.

Finally, the sheet can be customized. The amount of fiber, aerogel, and binder can be changed to fit different needs. For example, a thinner sheet with more aerogel can be used where space is tight but extra heat blocking is needed. A thicker, stronger sheet can be made for heavy-duty battery packs. This flexibility makes the invention useful for many different battery designs and markets.

Conclusion

The new heat insulation sheet for rechargeable lithium batteries brings together the best features of old and new materials. It blocks heat very well, handles pressure as batteries swell, and is tough enough to last a long time. By carefully stacking aerogel, fibers, binders, and mica, the sheet meets the growing need for safer, more reliable batteries in everything from cars to phones.

For anyone working with battery design, electric vehicles, or energy storage, this invention is a big step forward. It is simple to make, easy to use, and can be adjusted for different needs. As the world moves toward more electric vehicles and devices, safer batteries will become even more important. This heat insulation sheet is a smart, flexible solution that can help make that future safer for everyone.

Click here https://ppubs.uspto.gov/pubwebapp/ and search 20250337055.