JPH0557714B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has at least two terminals and at least one anode chamber and at least one cathode chamber, each of the anode chamber and the cathode chamber each having at least one current collectors, separated from each other by an alkali ion-conducting solid electrolyte, and at least partially defined by a metal case;
Concerning alkali metal and chalcogen based chemical batteries.

The rechargeable electrochemical cell described above with solid electrolyte is highly suitable for constructing high energy and power density storage batteries. Such storage batteries are increasingly being used as a source of electrical energy for electric vehicles. A solid electrolyte made of, for example, beta aluminum oxide used in an alkaline chalcogen battery is characterized by an extremely high partial conductivity for moving ions and a tens of times lower partial conductivity for electrons. By using such solid electrolytes in the construction of chemical cells, self-discharge becomes virtually impossible. This is because electronic conduction can be ignored and the reactants cannot pass through the solid electrolyte as neutral particles.

For the production of accumulators or high-temperature battery banks, a large number of the above-mentioned chemical cells are connected to each other. For example, in a high-temperature battery array for an electric vehicle, it is necessary to connect a large number of chemical batteries in series and a very small number of batteries in parallel. The reason is that the unit energy of such high-temperature battery arrays is generally 40 kWh or less, but
This is because the unit energy of an individual battery is 80Wh or more. Therefore, the high-temperature battery array includes 500 batteries or less. If the voltage of the individual battery is about 2V,
If you want to generate a total of 200V with the above battery string, you will need to connect 100 batteries in series. This means that up to 5 batteries can be connected in parallel. When one or more batteries in this series connection is overloaded, the temperature inside the batteries increases. An increase in temperature above the operating temperature of the battery may lead to battery destruction. Since such a defective battery will have a high ohm, the entire flow of batteries through the series circuit in which it resides will be interrupted.

A chemical cell is known from DE 28 19 583 A1, in which the current circuit is interrupted when the temperature of the cell rises far above the operating temperature. In this cell, at least one of the two current collectors consists of two pieces. The first part is arranged outside the battery and the second part inside. Both parts are connected to each other by electrically conductive contacts which melt at a temperature above the operating temperature of the cell by a predetermined value. The battery circuit through the battery is thus interrupted. In this case, it is a disadvantage that the electrical conductivity of the current collector is reduced by subdivision into a plurality of sections, especially by intervening fusible contact elements. This is because the corrosion phenomenon of the contact portion results in a decrease in electrical conductivity. The present invention is based on the prior art mentioned at the beginning, and the internal temperature is
The object is to provide a chemical battery that is automatically disconnected from the current circuit of the high temperature battery bank when the operating temperature rises above 350°C.

According to the present invention, two terminals are integrated into one unit and are conductively (electrically) coupled to each other through an alloy that melts when the temperature inside the battery rises to a value above the operating temperature of the battery. By doing so,
The above objectives are achieved.

Another solution consists in bonding the two current collectors together via an electroconductive material that melts when the temperature rises to a value slightly above the operating temperature of the cell.

According to the invention, the first current collector is configured as a tube closed on one side, the closed end of which is arranged inside a cup-shaped solid electrolyte serving as a reactant chamber. As the second current collector, a metal casing is used which is also cup-shaped and is connected to the second reactor chamber. A second electrically conductive pipe is disposed inside the one-sided closed tube, the lower end of which is closed by a meltable electrically conductive stopper, and is disposed at a predetermined distance from the closed end of the outer tube. An insulator is disposed circumferentially between the inner surface of the outer tube and the outer surface of the inner tube. A conductive rod is placed inside the inner tube. This rod is placed in a recessed part of the stopper that closes off the inner tube. The rod is electrically conductively coupled to the stopper. The space between the rod and the inner tube can be filled with insulation, but even if left blank,
That is, it is sufficient that no conductive material is provided here. The rod is conductively coupled to the metal case of the battery. The inner tube is used as the first terminal and the upper end of the outer tube is used as the second terminal.
The plug closing the lower end of the inner tube is made of a conductive material that begins to melt at temperatures slightly above the operating temperature of the battery.

In the chemical cell according to the invention, when the temperature rises to a value above the operating temperature of the cell, melting starts from the plug at the lower end of the inner tube. The lower end of the inner tube is spaced apart from the closed end of the outer tube such that the space between the two tubes is completely filled with the molten material of the stopper, electrically connecting the tubes. .

If the temperature inside the battery rises for a long time, the stopper will completely melt. Electrical contact is thereby broken between the inner tube and the metal ace of the battery. The molten material of the plug then forms an electrical connection between the inner tube and the outer tube, which serves as current collector and terminal. This procedure bridges the current circuit through the chemical cell. No current flows through the battery anymore, and no short circuit current flows either. This ensures that the battery does not become high ohmic. The charging and discharging current flowing through the remaining batteries has no effect on this battery.

In a second solution according to the invention, the metal casing of the battery is again utilized as current collector, while the second current collector consists of a tube closed on one side. The closed end of this second current collector projects into the cup-shaped solid electrolyte. A conductive cylinder is disposed inside the tube, the lower end of which is at a predetermined distance from the bottom of the tube. Insulation is disposed circumferentially between the outer surface of the inner column and the inner surface of the tube. The cylinder has a hole lined with an insulating material at its lower end, which is conductively connected to the metal case of the battery through an electric wire serving as a terminal. A metal component that can be melted at a predetermined temperature is inserted into this hole and held within the hole. The components are made of an alloy that can be melted at a temperature slightly higher than the operating temperature of the battery. The spacing between the cylinder and the bottom of the tube is selected such that the molten component material completely fills the space between the cylinder and the tube and forms an electrically conductive bond between the tube and the cylinder. The component and the tube, which acts as a second current collector and is closed on one side, are connected in at least a thermally conductive manner so that the component responds immediately to temperature changes within the battery. When the normal charging and discharging process of the battery is disrupted or the battery is overloaded, this will lead to an increase in the temperature inside the battery. If the temperature inside the battery rises well above the operating temperature of 350 degrees Celsius, the components located inside the cylindrical holes begin to melt. If it is a relatively long failure, the component will completely melt. Because the melt completely fills the space between the cylinder and the tube,
A conductive bond is formed so that the two current collectors of the cell are shorted together. The short circuit current then flows through the battery only until the battery is completely discharged. The flow of current through the battery is then completely interrupted.

Next, the present invention will be explained based on the drawings.

The chemical cell 1 shown in FIG. 1 is shown in vertical section.

This electrochemical cell based on sodium and sulfur essentially consists of a metal case 2, a solid electrolyte 3 and a rod-shaped current collector 4. The metal case 2 has a cup shape. Inside this cup-shaped case 2, a solid electrolyte 3 also formed in a cup-shape is arranged. The solid electrolyte 3 is made of beta aluminum oxide. Its dimensions are chosen such that a continuous gap 5 is created between the inner boundary surface of the metal casing 2 and the outer boundary surface of the solid electrolyte. In the embodiment shown here, this gap 5 serves as the cathode chamber. The inside of the solid electrolyte 3 is used as an anode chamber 6. The metal case 2 has an outwardly directed flange 8 at its open end. Above it rests the also outwardly facing flange 8 of the solid electrolyte 3. The flange 8 of the solid electrolyte 3 consists of an insulating ring made of alpha aluminum oxide. The connection between the solid electrolyte 3 and the insulating ring is made through a sealing glass (not shown). The insulating ring is formed so as to project outwardly from the solid electrolyte 3 and to take over the function of the flange 8 as well. Case 2
Preferably, a seal 9 is disposed between the flange 7 of the solid electrolyte 3 and the flange 8 of the solid electrolyte 3. The flange 8 of the solid electrolyte 3 completely closes the cathode chamber 5 between the case 2 and the solid electrolyte 3 to the anode chamber 6 and to the outside. The anode chamber 6 is closed by a closing plate 11 made of corrosion-resistant material. A closure plate 11 rests on the flange 8 of the solid electrolyte 3. A seal 10 is arranged between the flange 8 and the closure plate 11. metal case 2
The cathode chamber 5 between the solid electrolyte 3 and the solid electrolyte 3 is filled with a graphite fiber layer 12 impregnated with sulfur. In the embodiment shown here, the metal case 2 is used as the cathode current collector.
is used. The anode current collector 4 is formed into a rod shape,
It protrudes deeply into the cup-shaped solid electrolyte 3, particularly into the anode chamber 6. In the embodiment shown here, the anode chamber 6
is a metal fiber layer 13 impregnated with molten nitrium.
filled with. The metal fiber layer 13 is disposed so as to closely surround the anode current collector 4 and to be in close contact with the inner surface of the solid electrolyte 3. Since the metal fiber layer 13 acts as a capillary structure, the inner surface of the solid electrolyte 3 can be constantly moistened with sodium. The anode current collector 4 is, for example, a tube 1 made of steel and closed on one side.
Consists of 4. The closed end of this tube 14 is arranged in the lower area of the solid electrolyte 3. The open end of the tube 14 is inserted through the hole 15 of the closure plate 11 and outwardly,
It protrudes several millimeters from the closing plate 11. tube 1
A second tube 16 is disposed inside the tube 4, and the outer diameter of the second tube 16 is set to be slightly smaller than the inner diameter of the tube 14.
An insulator 17 is disposed circumferentially between the lateral interfaces of the two tubes (terminals) 14 and 16. tube 14
The end of the tube 16, which is located inside the tube, is closed by a plug 18. The plug 18 has a working temperature of 350°C.
Made of conductive materials, especially alloys, that begin to melt when exceeded. The end of the tube 16 closed with the stopper 18 is arranged at a predetermined distance from the closed end of the tube 14, so that a free space 19 is formed between the lower ends of the tubes 14,16. The size of the space 19 is selected such that, when the plug 18 melts, the molten alloy is accommodated by the space 19 and the alloy creates an electrically conductive connection between the tubes 14 and 16. . In order to obtain good conductive contact between tubes 14 and 16 in such cases, tubes 1
The insulation 17 arranged between the lateral interface between tube 16 and tube 16 does not extend completely to the lower end of tube 16 . A conductive rod 20 is disposed inside the tube 16, and its lower end is disposed in the recess 25 of the stopper 18. stick 2
0 is electrically conductively coupled to tube 16 via plug 18 . The upper end of the rod 20 is connected to the battery 1 via an electric wire 21.
It is preferable that the metal case 2 is electrically conductively connected to the metal case 2 of the present invention. Between the inner surface of the tube 16 and the outer surface of the rod 20,
An insulator 22 is provided. It is a solid cylinder of insulation with a through hole into which the rod 20 is inserted and held. The outer diameter of the above cylinder is the tube 16
This cylinder can be inserted inside the tube 16
sized so that it is retained between the inner surfaces of the For example, polytetrafluoroethylene is suitable as the insulator. A hole having an inner diameter slightly smaller than the outer diameter of the rod 20 is formed for the rod 20 in such a cylinder. In that case, in order to insert the rod 20 into the hole,
Heat the cylinder to a temperature of 400 to 500°C. The inner diameter of the hole is thereby enlarged and the rod 20 can be inserted. When the cylinder 22 is cooled to room temperature, the inner diameter of the hole becomes slightly smaller again so that the cylinder 22 tightly surrounds the rod 20. The outer diameter of the cylinder 22 is selected to be slightly larger than the inner diameter of the tube 16. In order to insert the cylinder 22 into the tube 16, the cylinder 22 is cooled to a temperature below room temperature. At that time, the outer diameter of the cylinder becomes slightly smaller. The cylinder can then be easily inserted inside the tube 16. When the cylinder 22 is heated to room temperature again, it assumes its original size again. Therefore, since it is tightly pressed against the inner surface of the tube 16, it is tightened and stabilized inside the tube 16.

In the embodiment shown here, the upper end of the tube 16 is connected to a wire 23 through which it is connected to an adjacent battery (not shown). A second electrical wire 24 is connected to the top end of tube 14 and is also used for connection to another battery (not shown here).

Battery operating temperature inside battery 1, i.e. 400
If a temperature increase occurs that exceeds a temperature value of 0.degree. C. or more, the plug 18 will begin to melt. For the production of this stopper, an alloy with a melting point of 350 to 400° C. is used. When the plug 18 completely melts, the conductive connection between the rod 20 and the tube 16, which is conductively connected to the metal case of the battery, is completely interrupted. The alloy flowing into space 19 completely fills this chamber 19 and forms an electrically conductive connection between tube 14 and tube 16. Metal case 2 and battery 1 that serve as a current collector for cathode chamber 5
By interrupting the electrically conductive contact between the connecting electrodes 16 of the cell, the current circuit via this battery is interrupted. The electrical connection between tubes 14 and 16 bridges the battery. When the battery 1 is inserted in a series circuit of multiple batteries (not shown here), the charging/discharging current of the other batteries in this series circuit is transferred between the two terminals (tubes) 14 and 16. This current flows through the battery 1 and has no effect on the battery 1. Therefore, incomplete discharge of the battery 1 and short-circuit current flow will not occur. For example, if a battery connected in series with this battery has not yet been completely discharged, the discharge current coming from this battery will flow through the two terminals 14, 16.

Chemical cell 1 also shown in vertical cross section in Figure 2
substantially consists of a metal case 2, a solid electrolyte 3, and a rod-shaped current collector 4. The metal case 2 also has the shape of a cup. Inside the case 2, a solid electrolyte 3 also formed in a cup shape is arranged. The solid electrolyte 3 is again made of beta aluminum oxide. Its dimensions are chosen such that a continuous gap 5 is created between the inner boundary surface of the metal case 2 and the outer boundary surface of the solid electrolyte 3. In the embodiment shown here, this gap 5 is used as a cathode chamber. The cathode chamber is filled with a layer of graphite fibers 12 impregnated with sulfur. The interior of the solid electrolyte 3 is used as an anode chamber 6. The upper end of the metal case is provided with a flange 7 which also faces outward. On top of this is placed the also outwardly facing flange of the solid electrolyte 3. The flange 8 of the solid electrolyte 3 consists of an insulating ring made of Arifa aluminum oxide. The connection between the solid electrolyte 3 and the insulating ring 8 is achieved by a sealing glass (not shown here). The insulating ring (flange) 8 protrudes outward from the solid electrolyte 3,
At the same time, it is formed to take charge of the function of the flange 8. Preferably, a seal 9 is provided between the flange 7 of the case 2 and the flange 8 of the solid electrolyte 3. The flange 8 of the solid electrolyte 3 completely closes the cathode chamber between the case 2 and the solid electrolyte 3 to the anode chamber 6 and to the outside. Closing of the anode chamber takes place by means of a closing plate 11 made of corrosion-resistant, non-conducting material. The closing plate 11 rests on the flange 8 of the solid electrolyte 3. A seal 10 is arranged between the flange 8 and the closure plate 11. In the embodiment shown here, the metal case takes charge of the function of the cathode current collector. The anode current collector 4 has the shape of a rod and protrudes deeply into the cup-shaped solid electrolyte 3 , particularly into the anode chamber 6 . Anode chamber 6
is filled with a metal fiber layer 13 impregnated with molten sodium. The metal fiber layer 13 closely surrounds the anode current collector 4 and is disposed in close contact with the inner surface of the solid electrolyte 3. Since the metal fiber layer 13 has a capillary structure, the inner surface of the solid electrolyte 3 can be constantly wetted with sodium. This is absolutely necessary for optimal functioning of the battery 1. The anode current collector 4 consists of a steel tube 4R with one side closed. The closed end of the tube 4R is disposed within a cup-shaped solid electrolyte. A rod or cylinder 14 made of a conductive material is disposed inside this tube 4R. The outer diameter of the cylinder 14 is slightly smaller than the inner diameter of the tube 4R. Since the insulator 15 is disposed circumferentially between the inner surface of the tube 4R and the outer surface of the cylinder 14, no electrically conductive connection is formed between the tube 4R and the cylinder 14. The end of the cylinder 14 disposed inside the tube 4R is
It has a hole 16 passing through the longitudinal axis of the cylinder 14. The hole is lined with an insulator 17. A component 18 that melts at a predetermined temperature is disposed inside the hole 16 and is held therein. This component 18 is made of an alloy that begins to melt at a temperature slightly above the operating temperature of the battery. The length of the component 18 is selected so that it makes at least thermally conductive contact with the end of the tube 4R. The lower end of the cylinder 14 is
It is arranged at a predetermined interval from the closed end of the pipe 4R. This spacing is selected such that the volume of the space 19 remaining between the cylinder 14 and the tube 4R is the same as the volume of the component 18. The dimensions of the space 19 are such that, especially when the temperature rises above the operating temperature of the battery, the molten component material completely fills the space 19 and forms an electrically conductive bond between the cylinder 14 and the tube 4R. Select the In the embodiment shown here, the open end of the tube 4R is passed out through a central hole in the closure plate 11 and overhangs the closure plate 11 by a few millimeters. The cylinder 14 protrudes outward from the battery 1 and connects the battery 1 with an electric wire 20 that serves as a connection electrode.
It is electrically conductively coupled to the metal case 2 of the battery 1 .
The upper end of the tube 4R is used as a second connection electrode. When a temperature increase occurs inside the cell, the two current collectors are electrically conductively coupled together by the melt of component 18.

The present invention is not limited to the embodiments shown in FIGS. 1 and 2, but the two current collectors or the two connecting electrodes are connected by melting the electrically conductive material when the temperature rises. Includes all chemical cells that are connected and shorted together. The batteries shown in Figures 1 and 2 are
It can also be used as a battery in which current flows in the opposite direction.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a chemical cell according to the present invention;
FIG. 2 shows a vertical cross-section of this battery variant. DESCRIPTION OF SYMBOLS 1... Chemical battery, 2... Current collector, 3... Solid electrolyte, 4... Current collector, 5... Cathode chamber, 6... Anode chamber, 14... Terminal (first tube), 16 ... terminal (second tube), 18 ... meltable component.

Claims (1)

[Scope of Claims] 1 It has an anode chamber and a cathode chamber, and the anode chamber and the cathode chamber are each equipped with a metal case and a metal tube, and the anode chamber and the cathode chamber are made of a cup-type alkali ion conductive solid electrolyte. the first
and a second metal tube, the first metal tube
The metal tube is formed into a tubular shape with one end closed,
and a closed end is disposed inside the cup-shaped alkali ion conductive solid electrolyte, a second metal tube is provided within the first metal tube, and a lower end of the second metal tube is made of a meltable alloy. the conductive stopper is closed, and the second metal tube is disposed at a predetermined distance from the closed end of the first metal tube, with a space between the ends of the first and second metal tubes. By filling the space with the molten plug, only the two metal tubes are electrically connected via the alloy, and the inner surface of the first metal tube and the second metal tube are connected to each other conductively. A first insulating material is provided in the upper part between the outer surface and the second metal tube, and a cylindrical conductive rod is provided in the second metal tube, and the conductive rod is connected to a concave portion of the stopper that closes the second metal tube. a lower end thereof is disposed within and conductively connected to the lower end, a second insulating material is provided between the conductive rod and a second metal tube, and the conductive rod is conductively connected to the metal case. Connected and battery 2
An alkali metal and chalcogen-based chemical cell, wherein one of the two electrical terminals is formed by a second metal tube and the other electrical terminal is formed by the first metal tube. 2. The metal case of the battery is connected to one of the two reaction spaces, acts as another current collector, and is electrically conductively connected to a conductive rod provided in the second metal tube. The chemical battery according to item 1.