Mobile phone body temperature charging system circuit diagram design

Mobile phone crystal 3.2*2.5mm 3225 26M (26.000MHZ) 7.5PF 10PPM 20PPM 30PPM

Single chip microcomputer STM32L151CCU6

One-piece inductor

Overview:
Mobile phones have become an indispensable communication tool in people's lives. At present, mobile phones are powered by rechargeable lithium-ion batteries. In the wild or without mains, the mobile phone may be out of power at any time, which brings a lot of inconvenience to the user. After researching that there is always a temperature difference between the human body and the environment, the use of thermoelectric technology can realize the true power of the mobile phone. Thermoelectric technology is a green energy-saving technology. It is a new energy replacement method that can effectively convert the heat of low-grade heat sources into electrical energy, while reducing energy consumption and alleviating environmental pollution problems. Therefore, the miniature thermoelectric device will have a good application prospect, and the mobile phone body temperature charging system must have important practical significance for the development of new energy.

Under normal circumstances, the infrared wavelength emitted by the human body is 8~12μm, and the heat energy generated by the human basal metabolism within 24 hours is 8 059.8 kJ. The surface area of ​​an adult's skin is about 2 m2 after being unfolded. The surface area is a measure of the average heat generated by energy metabolism within 1 h of approximately 167.9 kJ/(m2·h). The main heat-dissipating part of the human body is the skin. When the ambient temperature is lower than the body temperature, about 70% of the body heat is consumed by the radiation, conduction and convection heat of the skin. The skin temperature at the end of the limbs is the lowest, the closer to the trunk and head, the higher the skin temperature. In cold environments, as the temperature drops, the skin temperature of the hands and feet decreases most significantly, but the temperature of the head skin changes relatively little. It can be seen that the skin temperature of the head is the highest and it varies relatively little with the ambient temperature. Therefore, the body temperature charging system of the mobile phone is suitable for being installed inside the cap, which can improve the charging efficiency.

The mobile phone's lithium-ion battery can be reused by charging or adding energy, and its rated voltage capacity is generally 3.6 V (also 3.7 V). For example, the average working voltage of a lithium-ion battery of AA800 mAh is 3.6 V, the energy is 2.88 Wh, and the heat radiated per unit area of ​​human skin per unit time is about 32.65 W/m2, which is known by energy conversion. The energy radiated for 1 m2 of human skin is about 32.65 Wh. If the lithium ion battery is charged at a charging rate of 0.2 C (160 mA), it takes 5 h to fill the energy of 2.88 Wh. Lithium-ion batteries have a theoretical energy conversion efficiency of about 1.76%. Telkes developed a thermoelectric generator in 1947 with a power generation efficiency of 5%. Therefore, the conversion efficiency can meet the requirements long ago, and the body temperature of the human body is completely achievable in terms of energy conversion for charging the mobile phone.

Schematic diagram of semiconductor temperature difference battery:

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