JPH048607Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a sealed battery that uses lithium as a cathode and oxyhalide as an electrolyte solvent and anode active material.

In this type of sealed battery, the cathode can containing the battery elements is constructed from a deep-drawn stainless steel can, and a metal lid with a glass seal is inserted into the opening of the can, and the inner circumferential surface of the can and the metal lid are It uses a hermetically sealed structure in which the outer circumference is welded together using a hermetic seal.

For this reason, it has the characteristic of not leaking even under severe conditions, and because of this characteristic, it is common to fill the battery with a large amount of liquid oxyhalide, which serves as the solvent for the electrolyte and the positive electrode active material, to increase the energy density of the battery. In terms of applications, use in high-temperature atmospheres is being considered.

However, when the oxyhalide is filled at a high filling rate of 75% or more (usually up to 95% by volume) of the total amount of space inside the battery, it expands thermally and due to gas generation due to internal short circuits, etc. There is a danger that the battery container will bulge and eventually explode violently due to the sudden rise in internal pressure. That is, although this type of battery has excellent leakage resistance due to being a sealed type, the reality is that it cannot always be protected from the risk of explosion due to storage problems and handling problems.

In addition, in this type of battery, the cathode made of lithium is placed in close contact with the inner peripheral surface of the cathode can, but if this adhesion is poor, it becomes passivated at the interface and becomes difficult to collect current, making it difficult to function as a battery. There is a problem of not being able to fulfill the goals.

From the above point of view, this invention aims to provide a sealed battery with excellent adhesion between the lithium cathode and the cathode can and an explosion-proof structure. At the same time, the oxyhalide is used as the electrolyte solvent and the anode active material, and the cathode can containing these battery elements is constructed from a deep-drawn stainless steel can, with a metal lid welded to the opening to create a sealed structure. In a sealed battery in which the cathode is in close contact with the inner periphery of the side surface of the cathode can in this sealed structure, a plurality of annular grooves are formed at equal intervals on the inner periphery of the side surface of the cathode can; The sealed battery is characterized in that an annular groove is provided on the outer periphery of the side surface of the cathode can corresponding to at least one groove.

An embodiment of this invention will be described below with reference to the drawings.

In FIGS. 1 and 2, 1 is a cathode made of lithium, 2 is a separator such as a glass fiber nonwoven fabric, and 3 is a carbon porous molded product formed by adding polytetrafluoroethylene as a binder to acetylene black. 4 is an anode current collector made of stainless steel, 5 is a cathode can made of a deep drawn stainless steel can, 6 is a metal lid made of stainless steel, etc., and the outer circumferential side of this metal lid 6 is a cathode can. A glass seal 7 is formed on the inner circumferential side of the metal lid 6. After injecting the electrolytic solution through the metal pipe 8 which is welded to the seal 7 in advance, the anode current collector is 4 and a metal pipe 8 are welded to form a sealed structure inside the battery.

The above electrolytic solution is made by dissolving an electrolyte such as aluminum chloride or lithium chloride in an oxyhalide such as thionyl chloride (SOC ₂ ), sulfuryl chloride (SO ₂ C), or phosphorus chloride (POC ₃ ). The halide serves as a solvent for the electrolyte and as an anode active material. The capacity of this oxyhalide, together with the space capacity inside the sealed battery, is said to be at least 75% by volume and usually up to 95% by volume, which increases the energy density of the battery. It's getting bigger. The above space capacity refers to the total capacity of the cathode 1, separator 2, anode 3, anode current collector 4, and battery fillers such as electrolyte (calculated from true specific gravity and weight) based on the total internal volume within the battery.
is deducted.

Reference numeral 9 indicates a plurality of annular grooves formed at equal intervals on the inner circumference of the side surface of the cathode can 5, and reference numeral 10 indicates an annular groove formed on the outer circumference of the side surface of the cathode can 5.
Here, the width y of the groove 10 on the outer periphery of the side surface is designed to be at least 1.5 times the distance x from the lower end 11a of one groove 9a on the inner periphery of the side surface to the lower end 11b of the other adjacent groove 9b. However, this means that the groove 10 on the outer periphery of the side surface is provided at a position corresponding to at least one groove 9 on the inner periphery of the side surface. Approximately 0.1~ if the thickness of the stainless steel (before deep drawing) is 0.3mm
It is set to be 0.2mm. In this case, the depth of the groove 9 on the inner circumference of the side surface is approximately 0.05 to 0.1 mm.
The depth of the groove 10 on the outer periphery of the side surface is approximately 0.05~
It is about 0.1mm.

The grooves 9 and 10 are formed by cutting or press processing (in the case of the groove 10), for example.
The cross-sectional shape of both grooves 9 and 10 is not particularly limited to the rectangular shape shown in the figure, but can be any shape such as a semicircle or a triangle. In the figure, 12 is an insulating material made of resin or rubber provided to cover the metal lid 6.

As is clear from the above structure, in this invention, a plurality of annular grooves 9 are provided on the inner periphery of the side surface of the cathode can 5, which is made of a deep-drawn stainless steel can. When a battery is produced by pressure-welding the cathode 1 made of
The cathode 1 bites into the can and strongly adheres to the inner circumferential surface of the can, thereby preventing passivation at the interface as in the conventional case and sufficiently maintaining the original function of the battery.

Furthermore, since an annular groove 10 is provided on the outer periphery of the side surface corresponding to at least one groove 9 on the inner periphery of the side surface, the thickness of the can between the two grooves 9 and 10 becomes thinner, resulting in weaker strength. As a result, before an explosion occurs due to a sudden increase in the internal pressure of the battery, a crack occurs between the grooves 9 and 10, and the gas filling the inside is discharged from there.

As described above, according to this invention, the adhesion between the cathode and the cathode can is excellent, and the internal pressure of the battery increases rapidly and cracks occur between the grooves formed on the inner and outer peripheries of the sides of the cathode can before an explosion occurs. It is possible to provide a sealed battery having an explosion-proof structure that can generate gas and discharge the gas that has filled the inside beforehand.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing an example of a sealed battery of this invention, and FIG. 2 is a sectional view showing an enlarged main part of the sealed battery of this invention. 1... Cathode, 5... Cathode can, 6... Metal lid, 9
...Groove on the inner periphery of the side surface, 10...Groove on the outer periphery of the side surface.

Claims (1)

[Scope of utility model registration request] Lithium is used as the cathode, and oxyhalide is used as the electrolyte solvent and anode active material, and the cathode can containing these battery elements is constructed from a deep-drawn stainless steel can, with a metal lid welded to the opening. In a sealed battery in which the cathode is tightly attached to the inner periphery of the side surface of the cathode can in the sealed structure, a plurality of annular grooves are formed at equal intervals on the inner periphery of the side surface of the cathode can. A sealed battery characterized in that an annular groove is provided on the outer periphery of the side surface of the cathode can corresponding to the at least one groove.