What you may not know about heat-not-burn (HNB) baking technology is that according to authoritative reports, the export data of HNB electronic cigarettes reached 180 million USD in 2017, and by 2018, this figure had surpassed 1.5 billion USD, with an estimated 3 billion USD in 2019. With fierce competition among foreign tobacco giants, domestic tobacco companies have also joined the competition. Therefore, the core technology of heat-not-burn electronic cigarettes - heating and baking technology has attracted much attention.
The heating blade technology is particularly important in determining the quality of a high-quality heat-not-burn electronic cigarette. Currently, heating patents for heat-not-burn products are mainly concentrated in three types of technologies: electric heating, fuel heating, and physicochemical reaction heating.
Electric heating technology is the most widely used and has the highest number of patent applications among mainstream technologies. As of 2017, the number of patents for electric heating has reached 400. There are already various electric heating technologies on the market, including resistance wire heating, electromagnetic induction heating, and magnetic particle homogenization heating. According to the different forms of heating bodies, heating bodies can be divided into heating blades (similar to IQOS, MC, and Gongfu), heating needles (similar to LiL, Bodi, and QOQ), heating cups, heating barrels, and heating pots (similar to GLO, IUOC), among which thick film heating blades and needle-type heating are prominent forms. According to the form of heating and baking, it can be divided into internal heating, external heating, and independent internal and external heating.
1. Thick film heating element
The heating element is directly inserted into the tobacco stick and heated from the inside out. The heat radiation path is from the inside to the outside, and this internal heating method is the earliest used heating method. IQOS uses ceramic thick film heating element, which is also a benchmark product in the industry.
2. Needle-type heating
Needle-type heating uses a central heating needle for heating. Boditech's non-burning product is the world's first needle-type heating technology. Currently, lil by Korean tobacco company KT&G is the most well-known needle-type heating product. Needle-type heating can be divided into two-line heating needle and four-line heating needle, with four-line heating needle being an upgraded version of the two-line heating needle, with more stable and safer performance. Korean brands lil and QOQ by Yen & Frogs Technology both use four-line heating needles.
3. Surrounding heating
Surrounding heating is a typical heating method, including heating cups, heating pipes, and heating pots. This method accurately controls the temperature through segmented heating. However, the heat utilization rate of this method is relatively low, with some of the heat being absorbed by the tobacco and the rest being dissipated as heat. If the insulation is not done well, the heating device may become too hot. Glo by British American Tobacco is a typical surrounding heating product.
4. Independent internal and external heating
Independent internal and external heating uses two independent heat sources, with a complex structure and higher control difficulty, but it can achieve more thorough baking effect and higher thermal conduction bonding between the internal and external parts. Shenzhen Lvxinfeng Technology Co., Ltd. has launched the world's first non-burning electronic cigarette MOX-IOH with independent internal and external heating, combining internal needle-type heating and 360-degree circular external heating.
5. MIX 3D vertical full-surrounding heating
MIX 3D vertical full-surrounding heating uses a relatively low temperature method to heat the tobacco stick, and uses intelligent chip temperature control to achieve all-round temperature control of the tobacco stick. MIX 3D vertical full-surrounding heating heats from the bottom to the top of the tobacco stick, similar to the ignition method of real tobacco, so that every strand of tobacco can be fully dried, carbonized uniformly, and the utilization rate of the tobacco stick can reach 100%.
The above heating methods all use resistive heating by adjusting voltage or current to generate heat.
6. Magnetic Particle Homogeneous Heating Technology
Magnetic particle homogeneous heating technology uses non-contact magnetic induction energy transfer to achieve low-temperature homogeneous heating. By utilizing the principle of magnetic flux alternating frequency, it solves the problem of uneven heating of tobacco products during smoking.
7. Electromagnetic Heating
Electromagnetic heating is a method of heating tobacco rods using the principle of electromagnetic induction. The heating tube is wrapped with a magnetic induction coil that provides an alternating magnetic field. When an electric current is passed through the induction coil, a high-frequency magnetic field is generated, which induces heat in the heating tube. This method avoids direct contact between the heating tube and the outer shell of the smoking device, improves the insulation effect, and solves the problem of high temperature on the outer wall of the smoking device.
Currently, there are several patents filed for electromagnetic heating, including a patented invention titled "Electromagnetic Induction Low-Temperature Heating Smoking Device" published by the National Intellectual Property Administration in 2018. In addition, Loto Labs, a Silicon Valley startup, is the world's first company to use electromagnetic induction for powering vaporizers. Their flagship product, the "Evoke" vaporizer, utilizes patented technology of electromagnetic induction heating system.
Currently, products using resistance heating are more common in the market, while electromagnetic induction and infrared heating are less common and still in the early stages of development. There are many technological gaps and ample room for innovation, making them a promising direction for the future development of non-combustible heating technologies.
In addition to the above-mentioned typical cases of electric heating, there are several other less commonly used technologies, including:
Fuel heating technologies, which can be categorized into gaseous, liquid, and solid fuels. As of 2017, there were about 300 patents related to combustion heating technologies, but they are not widely applied in the market.
Physical and chemical reaction heating technologies, including physical crystallization and chemical reactions, etc. As of 2017, there were about 54 patents related to physical and chemical reaction heating technologies.
Ultrasonic atomization technology, which is breaking through the patent limitations of traditional heating atomization technology for electronic cigarettes, and developing a new generation of electronic cigarettes using ultrasonic atomization.