JPS59169080A - High temperature type battery - Google Patents

Abstract

PURPOSE:To provide a separator having good wettability to molten salt and sufficient porosity by using Li or Li alloy as a negative electrode, metal sulfide such as iron sulfide as a positive electrode, and placing a plate-shaped porous boron nitride obtained by using magnesia produced by heat decomposition as a binder between both electrodes. CONSTITUTION:A positive electrode 1 using metal sulfied such as iron sulfied or iron disulfied as an active material and a negative electrode 3 using Li or Li alloy as an active material are used, and a plate formed with porous boron nitride particles are placed between both electrodes. Porous boron nitride particles are prepared in such a way that magnesium nitrate solution corresponding to 20wt% magnesia is added to boron nitride particles having a particle size of, for example, 100-150mu, and they are dried and made in a plate shape, and burned to form a plate-shaped porous separator. Thereby, a battery using the separator which is low cost, easy to handle, and has good wettability to molten salt and sufficient porosity is provided.

Description

Detailed Description of the Invention The present invention uses Libram or a lithium alloy for the negative electrode, iron sulfide, iron disulfide, etc. for the positive electrode, and uses magnesia produced by thermal decomposition as a binder for the separator to form boron nitride particles. t regarding a molten salt battery using a plate-shaped
).

Conventionally, in high-temperature batteries that use molten salt, reparation materials have been selected in terms of stability at around 500°C, which is the iFJ+ temperature of the battery, corrosion resistance in molten salt, reactivity with active materials, etc. Boron nitride and magnesia are being considered. The pallet made of boron nitride is made porous by converting the boron nitride into fluorine. This felt separator has a high porosity of just under 90%, and fully satisfies the characteristics required for a battery's first separator, such as active material retention and electrical insulation. There was a problem in that the cost of forming a ferrite for manufacturing was extremely high. In addition, boron nitride ('L) does not wet the molten salt as it is, so after felting boron nitride, magnesia is precipitated on the surface of the cord using magnesium nitrate, which produces limagnesia, during thermal decomposition. ``Processing such as improving wettability to molten salt is necessary'').

Magnesia so far! Since 1illf formation has not been carried out, attempts have been made to use magnesia powder as a separator. However, the leverator using powder has a small porosity of around 50%, which has the disadvantage that the utilization rate of the active material in the battery remains at a low value.

In addition, when assembling the battery, it is inconvenient to handle because it is a powder, and it requires processing such as press-molding the electrolyte powder and cane into a plate shape.

The present invention improves these drawbacks and provides a battery using a separator that is inexpensive, easy to handle, has good wettability to molten salt, and has sufficient porosity.

Examples thereof will be described in detail below.

First, from 100μ to 150μ of porous boron nitride particles.
20% by weight of an aqueous magnesium nitrate solution calculated as magnesia was added to μ, and it was dried to form a plate.
, a porous plate-shaped separator was manufactured by firing at 100°C. Using this separator, a lithium-iron sulfide battery according to the present invention as shown in FIG. 1 was assembled and a charge/discharge test was conducted.

In the figure, (1) is a positive electrode that uses iron sulfide as an active material, with a particle size of iron sulfide powder from 50μ to 300μ, and an electrolyte of liggram chloride-potassium chloride from 50μ to 150μ.
After adding 15% by weight of particles having a particle size of 15% by weight and filling it into a TEPCO body in the shape of 100g, it was press-molded at 100MPa at room temperature to form a plate. In addition, 200 mesh stainless steel 'Jr4't is placed on the surface of the electrode plate to hold the active material.
! Move the mesh of f to the right. (2) is a separator made of porous boron nitride particles hardened with magnesia according to the present invention;
) This is a negative electrode that uses a lithium-aluminum alloy as the active material. Similar to the positive electrode, the negative electrode also has a honeycomb-shaped current collector containing 50. Filled with lithium-aluminum alloy powder with a particle size of u to 300μ and 15% by weight of electrolyte powder with a particle size of 50μ to 10011, the pressure was 100MPa at room temperature.
It is a plate-shaped body that is pressure-formed. 200 mesh stainless steel Ff to retain active material even in the negative electrode! There are 4 types of nets. A 54% by weight lithium chloride potassium chloride molten salt was used as the electrolyte. Battery operating temperature is 470'
It was set as C.

The capacity of the positive electrode is 25Δh, and the capacity of the negative electrode is 1
．． It was tripled.

The porosity of the porous plate separator according to the present invention is 70%.
Although it is inferior to 89% of boron nitride fluorite, it is sufficiently porous compared to 46% of magnesia powder leverator, and in battery tests, the utilization rate of positive electrode active material during charging and discharging was 2.5△. In a battery with a similar configuration using a magnesia powder separator, the active material utilization rate was only 64%, and in a battery using a boron nitride felt separator, it was 86%. It became the same value.

As is clear from the above description and examples, the present invention
The present invention improves the drawbacks of conventional separators and provides a molten salt battery using a separator made of inexpensive boron nitride particles and a magnesium compound, which is porous and has good wettability to molten salt.

The battery using the separator according to the present invention also has the advantage that it is easy to handle even during assembly because the separator has a cocoon-like shape.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a battery according to the present invention. 1... Positive electrode, 2... Porous boron nitride particles.

Claims (1)

[Claims] Lidium or L Ribou 11 alloy is used for the negative electrode, metal sulfide is used for the positive electrode, and porous nitride foam is used between the electrodes using magnesia produced by thermal decomposition as a binder. A high-temperature battery characterized by intervening plate-shaped particles.