Composition of anode of low-polarization thermal battery

Abstract

The invention discloses a composition of an anode of a low-polarization thermal battery. The composition of the anode of the thermal battery comprises the following components in percentage by weight: 50-88 percent of pyrite, 1-15 percent of lithium oxide and 5-30 percent of low melting point eutectic salt. In the invention, two functional materials are added to an anode active substance so as to improve the electrochemical property of the thermal battery anode and the stability of battery output voltage, wherein one functional material is used for enhancing the wetting property of the anode and electrolyte and reducing polarization, while the other functional material is used for carrying out thermal protection on the anode active substance, improving the conducting property of the anode and reducing the polarization.

Description

technical field [0001] The invention relates to a heat battery, in particular to a composition of the positive electrode of the heat battery. Background technique [0002] The thermal battery is a heat-activated reserve battery. It is a disposable reserve battery that uses molten salt as an electrolyte and uses a heat source to melt it and activate it. The internal temperature is 450°C to 550°C during operation. Due to its small internal resistance, it has high specific energy and specific power, wide operating environment temperature, long storage time, rapid and reliable activation, compact structure, non-directionality during use and is not affected by installation orientation, and has good mechanical properties. It needs maintenance and other advantages, and it has been favored by the military circle since it came out, and has developed into an ideal power supply for modern weapons and emergency systems such as missiles, nuclear weapons, artillery, ejection chairs, and b...

AI Technical Summary

Problems solved by technology

[0003] However, due to poor electrical conductivity, large polarization, and poor temperature resistance of the positive electrode, thermal batteries produced by current technologies have problems such as high decomposition of active materials and low utilization of effective capacity, mainly as follows:

[0004] ①The active material decomposes more and the utilization rate of effective capacity is low

The decomposition activation energy of the positive active material pyrite (FeS2) is 227KJ / mol, which is a moderately stable substance, and the decomposition temperature begins at 350°C. If it is left at 500°C for 20 minutes, the capacity loss will be as high as 62%. Therefore, no technical measures should be taken for the battery More active material decomposition, low utilization rate of effective capacity

[0005] ② Poor electrical conductivity

Since pyrite, the active material of the positive electrode, is a semiconductor material, its electrical conductivity is not good, and the internal resistance of the battery is large during operation, which not only results in weak load capacity, but also causes thermal runaway, which brings safety hazards to the battery.

[0006] ③ large polarization

Due to the poor contact of the positive active material pyrite particles and the poor wettability with the electrolyte, the electrode reaction contact point is less, the activity is low, the polarization is large, the voltage drop is large under the condition of high current operation, and the load capacity is poor.