JPS59191273A - Nonaqueous solvent cell - Google Patents

Abstract

PURPOSE:To prevent explosion due to erroneous usage such as shortcircuit by forming the lead wire to be employed for connection between negative and positive poles with shape memory alloy. CONSTITUTION:Spiral electrode group 2 is contained in a can 1 through a caged separator 3 made of glass fiber unwoven cloth. A plastic sealing disc 9 is provided air-tightly at the upper face opening of can 1 and fixed with the positive pole terminal 11. The lower end of positive pole lead wire 15 made of Ni-Ti shape memory alloy is connected to the metal current collector of the positive pole strip 5 in the electrode group 2 while the upper end of the lead wire 15 is connected to the lead connecting chip 14 of positive pole terminal 11. Upon internal heating due to erroneous usage such as shortcircuit, the positive pole lead wire made of shape memory alloy will recover the original shape to interrupt connection with said chip 14 thus to open circuit.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to improvements in non-aqueous solvent batteries.

[Technical background of the invention and its problems]

Nonaqueous solvent batteries that use lithium and sodium as negative electrode active materials have high energy density and excellent storage characteristics.
It also has the feature of a wide operating temperature range, and is often used as a backup power source for calculators, clocks, and memory.

Among the above-mentioned batteries, batteries that use lithium as the negative electrode, use sulfur or phosphorus oxyhalides such as thionyl chloride or phosphyl chloride as the main positive electrode active material, and use a positive electrode made of carbon and metal current collectors have particularly low energy density. It is attracting attention because it is thick. However, since such a battery uses lithium for the negative electrode, the battery generates heat due to misuse of a chute, etc., and the temperature inside the battery increases, especially in a battery having a structure capable of discharging a large current. When the temperature rises above the melting point of lithium, the lithium melts and passes through the separator that separates the negative and positive electrodes and reaches the positive electrode, causing an internal short circuit that not only causes loss of electrical capacity but also generates intense heat. This may lead to an explosion, etc.
Extremely dangerous.

As a countermeasure to the above, there is no temperature limit on the outside or inside of the battery. There are some devices that are designed to prevent the dangerous situation described above by providing a circuit breaker due to the heat generated during misuse of the cichito etc. However, in such a battery, the fuse is assembled separately, which not only increases the number of parts but also complicates the structure and increases costs. In particular, when a fuse is attached externally, the appearance of the battery is improved.

In addition, some batteries are equipped with a safety valve so that even if the battery generates heat during misuse of a computer, the increase in internal pressure will activate the safety valve and prevent an explosion. however,
Batteries equipped with safety valves not only increase the number of parts and complicate the structure, resulting in higher costs, but also have problems in terms of reliability, as degassing cannot be performed reliably in some cases. Moreover, since a highly corrosive electrolyte (5 oct, etc.) is released into the battery along with the gas upon activation of the safety valve, there is a drawback that equipment in which the battery is installed is corroded.

[Objective of the Invention] The present invention aims to provide a safe and inexpensive non-aqueous solvent battery that can reliably prevent explosions due to misuse such as short circuits without increasing the number of parts or complicating the structure. It is something to do.

[Summary of the invention]

The present invention uses a shape memory alloy to form the lead wires used for connection to the negative and positive terminals housed in the housing, so that when the lead wires generate heat during misuse, the wires retain their memorized shape, and the terminals are The main point is to avoid dangers such as explosions by opening them. As described above, according to the present invention, dangers such as explosion can be avoided by the shape memory effect of the lead wire without separately providing fuses and safety valves as in the past.
It is possible to prevent the cost from increasing due to the increase in the number of parts and the complexity of the structure, and it is also possible to eliminate the corrosion of battery-powered equipment, such as when using a safety valve.

The positive electrode or negative electrode lead wire should have the role of opening the battery circuit before the lithium, which is the negative electrode, dissolves due to heat generation and temperature rise due to misuse such as short circuit, that is, before short circuit between the negative electrode and the positive electrode occurs. Therefore, it is necessary to select a shape memory alloy that exhibits a shape memory effect at a temperature lower than the melting point temperature of lithium as the shape memory alloy forming the lead wire. Such shape memory alloys include, for example, N1-T
i alloy, Cu-Zn-Al! alloy, Au-C'd alloy,
Examples include In-Te alloy and In-Cd alloy. In addition, among shape memory alloys, those that are reversible (return to the memorized shape due to an increase in temperature and return to the original shape at the time of processing when the temperature decreases), for example, when two shape memory alloys are mechanically separated directly from each other. If you use a cable connected to the terminal, the battery circuit can be opened due to heat generation due to misuse such as a short circuit, and when normal use is resumed, the lead wire will be connected to the terminal. Usage becomes possible.

[Embodiments of the invention]

Next, an actual lrm example of the present invention will be explained with reference to the drawings.

The eleventh cell 1 is a D-sized spiral lithium-thionyl chloride battery, and 1 is an integral piece made of stainless steel, for example, which also serves as a negative electrode terminal. A spiral electrode group 2 is housed in the housing I with a cage-shaped separator 3 made of nonwoven glass fiber fabric interposed therebetween. This electrode group color is strip-shaped, negative electrode 4 and strip-shaped positive electrode 60.
It is formed by spirally winding a laminated plate with a separator 6 interposed therebetween so that the band-shaped positive electrode 5 is exposed on the inside and outside.

The strip-shaped negative electrode 4 is made by, for example, pressing a commercially available metal lithium thin plate onto a nickel mesh (metal current collector). The positive electrode 5 is made by, for example, forming a sheet of a mixture of commercially available acetylene black, polytetrafluoroethylene (binder), and ethyl alcohol, pressing this onto a stainless steel net (metal current collector), and then heating and drying it. The sheet-like material is made into a porous carbon layer. The separator 6 is made of a nonwoven glass fiber fabric, and is impregnated with thionyl chloride (separate liquid) in which, for example, 1.5 mol/l of LiA/C/ is dissolved.

A cylindrical separator 7 made of a nonwoven glass fiber fabric is provided on the strip-shaped positive electrode 5 inside the spiral electrolytic group.

The metal collection body of the strip-shaped negative electrode 4 of the electrode group B is connected to the shrunken body I via a negative electrode lead wire 8 made of a nickel piece.

Further, a disk-shaped sealing plate 9 made of glass is airtightly provided at the upper opening of the 11th frame I. A hole 1o is formed in the center of this sealing IF board 9. A positive electrode terminal U is attached to the sealing plate 9. This positive terminal port is connected to the entire elliptical plate 12 placed on the upper surface around the hole 10 of the sealing plate 9, and the circular plate 12 inserted into the hole 10 of the sealing plate 9 through the circular plate I2. A rivet 13 for pressing and fixing the plate Z2, and a lead connecting piece 1 crimped to a portion protruding from the lower surface of the plate 9 to seal the rivet 13.
It is composed of 4. As shown in FIG.
Ti-based shape memory alloy (product name: Tynel, manufactured by Raychem)
The lower end of the positive 4'f IJ- wire 15 is connected and fixed, and the upper end of the lead @15 is pressed and connected to the lead connecting piece 14 of the positive terminal 11.

This positive electrode lead wire 15 is made by bending the upper end into a U-shape as shown in FIG. 2(b) at 300°C and then stretching the upper end as shown in FIG. 2(a). It has a shape that is bent once, and its elastic force normally connects it to the lead connection piece 14 under pressure, as shown in FIG.

According to the present invention, the positive electrode lead @15 made of a shape memory alloy maintains the shape shown in FIG. When assembled, it is electrically connected to the lead connection piece 14 of the positive terminal 2 due to its elastic action. In such a battery, if the inside of the battery generates heat due to misuse such as a short circuit, and the temperature of the positive electrode lead wire 15 exceeds the melting point of the shape memory alloy that constitutes it, the positive electrode lead wire will be memorized at a high temperature as shown in FIG. 2(a). The electrical connection with the lead connection piece 14 of the positive terminal port is interrupted by the elastic force, and the circuit is opened. As a result, the battery generates heat, and since the stability does not increase any further and does not reach the melting point of lithium (negative electrode), the melted lithium bends through the separator 6 and reaches the positive electrode 5, causing further abnormal heat generation. It is possible to avoid the possibility of causing an explosion.

Therefore, by forming the positive electrode lead wire with a shape memory alloy, it is possible to avoid explosions due to misuse such as short circuits, and the number of parts can be reduced compared to the conventional case where fuses and safety valves are installed separately. This makes it possible to reduce costs and facilitate the production of batteries.

1. If the positive electrode lead wire 15 is made of a memory alloy formed by mechanically connecting two Ni-T1 alloys in series, it is possible to use the positive electrode lead wire 15 again when the user notices misuse and returns to normal use. The state shown in FIG. 2(a) changes to the shape shown in FIG. 2(b), and the positive electrode terminal U is electrically connected to the IJ-cord connecting piece 14, so that the battery can be reused. On the other hand,
In a conventional battery having an additional fuse inside, the positive electrode lead wire is formed using a shape memory alloy in the above embodiment, but the present invention is not limited to this. For example, the negative electrode lead wire may be formed of a shape memory alloy, and, of course, both the positive electrode and negative electrode lead wires may be formed of a shape memory alloy. In addition, due to the structure of the battery, some batteries have a structure in which the negative electrode lithium is directly crimped to the inner surface of the 1Ii1# body that also serves as the negative electrode terminal, without using a negative wire. The lead wire may be formed of a shape memory alloy.

In the above embodiment, an electrode group in which the positive electrode and the negative electrode were spirally wound with a separator interposed therebetween was used, but the negative electrode and the positive electrode may each have a cylindrical shape, and a separator may be interposed between them.

〔Effect of the invention〕

As detailed above, the present invention provides a safe and inexpensive non-aqueous F battery that can prevent explosions due to short-circuits or other erroneous use without increasing the number of parts or complicating the structure. Can be provided.

FIG. 1 is a cross-sectional view of a lithium-thionyl chloride battery showing an embodiment of the present invention, FIG. 2(a) is a front view showing the shape memory state of the positive electrode lead wire, and FIG. FIG. 3 is a front view showing a regular lead wire processed from the shape memory state shown in FIG.

1... ili body, pod... spiral electrode group, 3...
Bottle-shaped separator, 4... Strip-shaped negative electrode, 5... Strip-shaped positive electrode, 8... Negative electrode lead, 9... Sealing plate, U... Upper electrode terminal, 14... Lead connection piece, I5...Positive lead wire.

Applicant's agent: Patent attorney Takehiko Suzue Figure 1 Figure 2 (a) (b)

Claims (1)

[Claims] A negative electrode and a positive electrode made of a light metal are provided in a housing that also serves as a negative terminal via a separator, and the negative electrode is connected to the integral body directly or via a lead wire, and the positive electrode is attached to the housing in an insulated state. In a non-aqueous solvent battery connected to the positive electrode terminal via a lead wire and further containing an electrolytic solution containing sulfur or phosphorus oxyhalide as the main positive electrode active material in the case, as the lead wire of the positive electrode or negative electrode. A nonaqueous solvent battery characterized by using a battery formed from a shape memory alloy.