JPS59203376A - Nonaqeuous solvent battery - Google Patents

Abstract

PURPOSE:To surely prevent explosion caused by incorrect use such as short in a nonaqueous solvent battery by forming a lead wire using to connect a negative electrode and positive electrode which are accommodated in a can to each terminal, with a shape memorizing alloy. CONSTITUTION:In a spiral lithium-thionayl chloride battery, a belt-shaped negative electrode 4 of an electrode group 2 is connected to a can 1 by a negative lead wire 8 such as a nickel peace. A positive lead wire 15 comprising a shape memorizing alloy such as Ni-Ti familh alloy is connected and fixed to a belt- shaped positive electrode 3, and also press-connected to a lead peace 14 of a positive terminal 11. In this battery, when heat is generated inside the battery by incorrect use such as short, the positive lead 15 returns to a shape memorized at high temperature, thereby connection is cut and circuit is opened. Therefore, heat generation is discontinued. When the negative lead wire 8 or both lead wires 8 and 15 are made with shape memorizing alloy, the same effect is also obtained.

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, lithium is used as the negative electrode, and sulfur or phosphorus oxy-
・Batteries that use logonides as the main positive electrode active material and positive electrodes made of carbon and metal current collectors are attracting attention because of their particularly high energy density. However, since such a battery uses lithium for the negative electrode, the stain pond generates heat due to misuse of a chute, etc., and the temperature inside the battery rises, especially in a battery having a structure capable of discharging a large current. If the temperature rises above the melting point of lithium, the lithium will melt and pass through the separator that separates the negative and positive electrodes, reaching the positive electrode, causing an internal short-circuit and causing loss of electrical capacity, or generating intense heat. It is extremely dangerous if the explosion occurs.

As a countermeasure to the above, a temperature fuse is installed on the outside or inside of the battery to cut off the circuit in case of heat generation due to short circuit or other misuse.
There are some things that have been taken care of to avoid the dangerous situation mentioned above. 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 cost. In particular, when a fuse is attached externally, the appearance of the battery is impaired.

In addition, some batteries are equipped with a safety valve so that even if they generate heat due to misuse such as a short circuit, the safety valve will be activated due to the increase in internal pressure and an explosion will not occur. however,
Batteries equipped with safety valves not only increase the number of parts and complicate the structure, resulting in higher costs, but also pose problems in terms of reliability, as gas may not be removed reliably. Moreover, since a highly corrosive electrolytic solution (SOct2, etc.) is released into the stain pond along with the gas due to the operation of the safety valve, there is a drawback that equipment in which the battery is installed is corroded.

[Purpose of the invention]

The present invention aims to provide a safe and inexpensive nonaqueous solvent battery that can reliably prevent explosions due to misuse such as short circuits without increasing the number of parts or complicating the structure.

[Summary of the invention]

In the present invention, the lead wires used for connection to the negative and positive terminals housed in the case are made of a shape memory alloy, so that when the lead wires generate heat during misuse, the lead wires are shaped into a 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 due to 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 an increase in the number of parts and the complexity of the structure, and it is also possible to prevent corrosion of battery-powered equipment, such as when a safety valve is used.

The positive electrode or negative electrode lead wire has the role of opening the battery circuit before the lithium that is the negative electrode dissolves due to heat generation or temperature rise due to misuse such as short circuit, or short circuit between the negative electrode and the positive electrode. Therefore, it is necessary to select a shape memory alloy for forming the lead wire that exhibits a shape memory effect at a temperature lower than the melting point of lithium. Such shape memory alloys include, for example, Ni-Ti
alloy, Cu-Zn-At alloy, Au-Cd alloy,
Ill-Ti alloy, In-Cd alloy, etc. can be mentioned. In addition, among shape memory alloys, those that are reversible (return to the memorized shape when the temperature rises, and return to the original shape at the time of processing when the temperature falls), for example, two shape memory alloys that are mechanically If you use something connected in series with the
When returning to normal use, the lead wires are connected to the terminals, allowing the battery to be reused.

[Embodiments of the invention]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a D-size spiral-shaped lithium-thionyl chloride battery, and numeral 1 indicates a case made of stainless steel, for example, which also serves as a negative electrode terminal. A spiral electrode group 1 is housed in the housing 1 via a box-shaped separator 3 made of non-woven glass fiber fabric. This electrode group 2 is formed by spirally winding a laminated plate with a separator 6 interposed between a strip-shaped negative electrode 4 and a strip-shaped positive electrode 50 so that the strip-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 forming a sheet of a commercially available mixture of acetylene black, polytetrafluoroethylene (binder), and ethyl alcohol, and then forming the sheet into a stainless steel mesh (
The sheet-like material is formed by pressing it onto a metal current collector and then heating and drying it to form a porous carbon layer. The separator 6 is made of a non-woven glass fiber fabric and is impregnated with, for example, thionyl chloride (electrolytic solution) in which 1.5 mol/l of L t hct4 is dissolved.

A cylindrical separator 2 made of a nonwoven glass fiber fabric is provided on the strip-shaped positive electrode 5 inside the spiral electrolytic group 2 . The metal current collector of the strip-shaped negative electrode 4 of the electrode group 2 is connected to the housing 1 via a negative electrode lead wire 8 made of a nickel piece.

Further, a disk-shaped sealing plate 9 made of plastic is airtightly provided at the upper opening of the housing 1. A hole 1θ is opened in the center of this sealing plate 9. The sealing plate 9
A positive electrode terminal 11 is attached to. This positive terminal 1
1 is a metal disc 12 arranged on the upper surface around the hole 10 of the sealing plate 9, and a metal disc 12 that penetrates through this disc 12 and is inserted into the hole 1θ of the sealing plate 9 to suppress the disc 12. It consists of a rivet 13 for fixing, and a connecting piece 14 which is caulked to the part of the rivet 13 that protrudes from the lower surface of the sealing plate 9. The lower end of a positive electrode lead wire 15 made of a Ni-Ti shape memory alloy (trade name: Tynel, manufactured by Raychem Corporation) is connected and fixed to the metal current collector as shown in FIG. The upper end of 15 is the lead connection piece 14 of the positive terminal L
Connected to the press.

This positive electrode lead wire 15 is made by bending the upper end into a U-shape at 300° C. as shown in FIG. It has a bent shape, and is normally connected to the lead connection piece 14 under pressure due to its elastic force, as shown in FIG.

According to the present invention, the positive electrode lead wire 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 electrode terminal due to its elastic action. In such a battery, if the inside of the battery generates heat due to short circuit or other misuse, and the positive electrode lead wire 15 reaches a temperature higher than the melting point of the shape memory alloy that constitutes it, the positive electrode lead wire 15 will be heated to a high temperature as shown in Fig. 2 (a). It returns to the memorized shape, and the electrical connection with the lead connection piece 14 of the positive electrode terminal 11 is cut off due to the elastic force.
The circuit is opened. As a result, the battery stops generating heat and the temperature does not rise any further and does not reach the melting point of lithium (negative electrode), so the dissolved lithium passes through the separator 6 and reaches the positive electrode 5, causing further abnormalities. This can avoid the risk of generating heat and causing an explosion.

Therefore, by forming the positive electrode lead wire with a shape memory alloy, it is possible to avoid explosions due to short-circuits or other misuse, which reduces the number of parts and simplifies the structure 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.

In addition, if the positive electrode lead wire 15 is made of a memory alloy formed by mechanically connecting two Ni-Ti alloys in series, when the user notices misuse and returns to normal use, the second lead wire 15 can be used again. When the state shown in the figure (,) changes to the shape shown in the figure (b), an electrical connection is made with the lead connection piece 14 of the positive terminal L, so that the battery can be reused. In contrast,
Conventional batteries with internal fuses cannot be reused after the fuse is disconnected and the circuit is opened.

In addition, although the positive electrode lead wire was formed using a shape memory alloy in the above-mentioned example, it 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 lead wire and the negative electrode lead wire may be formed of a shape memory alloy.

Additionally, due to differences in battery structure, some batteries have a structure in which the lithium negative electrode is directly pressed onto the inner surface of the casing, which also serves as the negative electrode terminal, without using a negative electrode lead wire. The 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, according to the present invention, it is possible to provide a safe and inexpensive non-aqueous solvent battery that can prevent explosions due to misuse such as short circuits, without increasing the number of parts or complicating the structure. .

[Brief explanation of drawings]

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 positive electrode lead wire processed from a shape memory state shown in FIG. DESCRIPTION OF SYMBOLS 1... Housing,... Spiral-shaped electrode group, 3... Cage-shaped senor Z-lator, 4... Strip-shaped negative electrode, 5... Strip-shaped positive electrode, 8
...Negative electrode lead wire, 9... Sealing plate, 11... Positive electrode terminal, 14... Lead connection piece, 15... Positive electrode lead wire. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 (a) (b) Continued from page 1 0 Posted by: Yu Sato - 1, Komukai Toshiba-cho, Saiwai-ku, Kawasaki City Shibaura Electric Co., Ltd. 0 applicants within the General Research Institute Toshiba Battery Co., Ltd. 3-4-10 Minamishinayo, Tokyo Parts Store

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 electrode terminal via a separator, and the negative electrode is connected to the housing directly or via a lead wire, and the positive electrode is attached to the housing in an insulated state. In a nonaqueous solvent battery, the lead wire of the positive electrode or the negative electrode is connected to the positive electrode terminal via a lead wire, and further contains an electrolytic solution containing sulfur or phosphorus oxyhalide as a main positive electrode active material in the case. A non-aqueous solvent characterized by using a shape-memory alloy as a solvent.