JPS59132575A - Electrochemical battery - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electrochemical cells, particularly electrochemical cells having two or more reactive components, at least one of which is in a liquid state at the operating temperature of the cell itself. Related to batteries. Although these components are separated from each other, they can react together with potentially undesirable results. The invention further relates to a method of reducing the potential risks resulting from such reactions.

According to one aspect of the invention, an electrochemical cell has two or more reactive components that are separated from each other, with potentially undesirable consequences. The at least one macroporous material is impregnated with or includes a macroporous material that contains said reaction products in one or more areas where contact between the reaction components can occur. in order to enhance and/or trap the components and thereby improve the ability to separate the components of the reaction product from each other.

The aforementioned potential dangers to be prevented by the present invention arise due to battery defects, especially damage caused by any accident. An example of such an accident is a motor vehicle accident where the battery forms part of the vehicle's propulsion system.

The reactive components of an electrochemical cell form reaction products when they come into contact with each other, and these components are inherently inert to the reaction products. These reaction products serve to separate the components of the battery from each other. Providing the battery with a macroporous material, as described above, increases the ability of the reaction products to separate the reactants from each other, resulting in reactions between the reactants that occur as a result of cell defects or accidental damage. Potentially preferred 1. In order to enhance and/or trap the reaction products in order to reduce the negative consequences.

This porous material can include, for example, macroporous particle bodies,
It may be a particulate, ie, fibrous or granular material to form a particulate layer or bed or the like.

Macroporous material in this case means a material that is impregnated with the liquid components of the cell in the sense of impregnation by capillary action or similar action. In contrast, atomic sieves obtained from zeolites etc.
Microporous materials such as ea) are materials with porosity at the atomic or molecular level and are p-impregnated by mechanisms other than the usual capillary reaction.

The particles may be free or unbound to each other and may move relative to each other. In this case, the porous material may have a density different from that of the reactants in contact with the material than to form a layer in the reactants at the operating temperature of the cell;
It occupies part of the space occupied by the reaction components.

Thus, for example, if contact between components is expected to occur at a high or upper level within a component, the particle size of the porous component may be less than the density of said component. the#
These particles form a bed suspended in the component at the upper level.

On the other hand, if contact is expected to occur at a lower or lower level, the particles of the porous material may have a greater density than the component. In this way, the particles settle to the bottom of the component (forming a rad or layer).

Although these particles are separated from each other, they may be brought into contact with each other by compression to form a compacted mass, and this may be impregnated with the above-mentioned components. In this case, the porous material almost entirely occupies the space occupied by the reactive component with which it is impregnated.

Alternatively, porous materials in the form of man-made objects, such as fabricated articles of fibrous material in the form of woven or felted materials, may also be used. Alternatively, the porous artifact may have a sponge-like structure, such as a sintered particle bed.
d bed of particles). ! ! II. In this case, the artifact may be sintered.

As mentioned above, the battery components that are impregnated into or surrounding and permeating the porous material are liquids, at least at the operating temperature of the battery. Therefore, the porosity of a porous material is
Preferably, the selection is such that the components in contact with the material at the operating temperature of the cell are able to freely diffuse through the material.

Typically, the component is often impregnated into the porous material in its entirety such that it surrounds and/or infiltrates the porous material, but in the present invention it is often the case that the specific type of The porous material is only applied in one or more areas within the cell where contact between the reacting components is expected to occur if damage is caused to the cell.

When the reacting components of a cell come into contact with each other in a gentle or non-disturbing manner, a layer of reaction products can form between the components, effectively separating the components and preventing or reducing further reactions between the components. . However, if a more or less catastrophic or major accident occurs, the cell will be substantially destroyed and the components will be almost thoroughly mixed. This phenomenon is particularly pronounced when all of the components are liquids, resulting in violent, uncontrollable reactions that may involve plate failure.

In such cases, even though a reaction product layer is formed between the components, if the accident or damage to the cell is large enough, this layer could possibly be repeatedly destroyed, causing the components to come into contact again with undesirable consequences. may worsen.

However, in the present invention, particles such as phi, which are present in the region where contact between the components occurs and reaction products are formed, strengthen the reaction product layer and cause mechanical failure. It can act to make it less susceptible to such effects. Alternatively, porous materials can trap and immobilize reaction products (
(as in the case of granular particles or spongy porous artifacts)
This increases the ability of the reaction products to separate components from each other.

Depending on the porous material used, both such reinforcement and entrapment can be achieved.

The two reactive components of the battery may be integral at the battery operating temperature, separated from each other by a separator, and both in contact with the separator.

At least one side of the separator is provided with a layer of porous material at the interface between the component on that side and the separator.

The layer may be a solid electrolyte, the components on either side of which consist of an anode material and a liquid electrolyte material, respectively. Said porous material layer may be provided at the interface between the liquid electrolyte and the solid electrolyte, and the anode material may consist of an alkali metal and/or an alkaline earth metal. The liquid electrolyte is also a molten salt electrolyte containing one or more alkali metal and/or alkaline earth metal halide salts, and the porous material layer is comprised of a non-conductive fibrous material.

Batteries of this type to which the present invention may be applied include batteries that include an anode, a cathode, a solid electrolyte between the anode and the cathode, and a liquid electrolyte in the cathode region. This liquid electrolyte functions as an ionic conductor and does not otherwise participate in the reactions of the cell, although it can react violently with the active anode material.

In such a case, the active anode material may be, for example, liquid sodium and the solid electrolyte is beta alumina (Beta A 1.03). The electrolyte is molten sodium aluminum chloride (NaAlCl4) surrounding the cathode material, which can be solid, porous, and active in the form of a matrix.

The beta alumina electrolyte effectively acts as a parator, separating the sodium aluminum chloride and the sodium, anode material. The liquid electrolyte and the anode are made of highly reactive substances, so if they come into contact with each other in the event of damage to the battery, they can cause dangerous reactions depending on the degree of mixing between them. can occur.

In the present invention, a porous material layer as described above, for example having a fibrous structure, is provided in a region where the liquid electrolyte can or is expected to react with the anode material in the event of cell damage, such as destruction of the solid electrolyte. It's fine. The inert reaction products formed by such reactions are reinforced by the fibrous structure described above, and are provided with a fiber-reinforced barrier that prevents the penetration of either the liquid electrolyte or the active anode material.
e-reinfored barrier). Similarly, the liquid electrolyte and the anode material, one or both of which are in a liquid state at cell operating temperatures.

The fibrous structure can be placed at the interface between the solid electrolyte and the liquid electrolyte as described above, but it can also easily be placed throughout the space within the cathode region containing the liquid electrolyte. Such fibrous structures may also be provided in the anode region, for example over the entire region or at the interface between the solid electrolyte and the anode material.

In this type of cell, the fibrous structure is preferably non-conductive, as described by KJ, and may be comprised of a ceramic material, alumina, glass fiber, or the like.

In the case of a cell having a cathode of the type that includes an artifact that is porous to the liquid electrolyte, such as a sintered workpiece, the invention provides that the fibrous material is heated by heating the fibrous material prior to formation of the artifact. It can also be incorporated into the cathode material, thereby aiding the sintering process and bonding of the cathode material.

Fourth, the present invention provides that at least one component is in liquid form at cell operating temperatures, separated from each other but capable of reacting with each other with potentially undesirable consequences, resulting in the formation of inert reaction products. The present invention also relates to a method for reducing the potential hazards created when two or more reactive components of such electrochemical cells come into contact with each other. The process comprises impregnating or impregnating the reaction product with at least one reaction component to enhance and/or trap the reaction product and thereby improve the ability of the reaction product to separate said components from each other. The macroporous material contained in the components is placed in one or more regions where contact between the reactants can occur.

The present invention will be explained in detail below by way of non-limiting specific examples based on the accompanying drawings.

Reference numeral 10 in FIG.
℃ and then the liquid sodium 'Niniyar, J:
The entire suitably heated vessel is shown in which liquid sodium aluminum chloride 14 is introduced at p 2 so °C.

These components were introduced one after another while gently adjusting the speed, and Ot! of Figure 1 was introduced. <Divided into two layers.

This introduction operation was carried out under Alzan air flow while heating the container 10 to 250°C. It has been found that sodium and sodium aluminum chloride undergo a rapid exothermic reaction at this temperature to form a solid reaction product as @1e according to the following reaction formula.

It has been determined that by adding the components slowly, layer 16 is formed to effectively separate the components from each other without unacceptable temperature increases.

The solid barrier constituted by this reaction product attenuated the reaction between the components by 451 J. Furthermore, it was found that the temperature increase was fl'J limited to less than 50°C.

Furthermore, if the Noriya 16 is destroyed in a large scale, for example by stirring, a violent reaction will occur and the @A degree will rapidly increase to 10 degrees.
It was found that the temperature rose to 00°C. This demonstrates the inherent danger when batteries containing sodium and sodium aluminum chloride are subjected to significant damage that causes these components to mix extensively and rapidly.

In FIG. 2, the electrochemical cell of the present invention is indicated generally at 18.

The battery includes a housing 20 in which molten sodium 22 is housed. A separator 24 made of a cup-shaped beta-alumina solid electrolyte is immersed in IJum 22 (partly melted) and contains a solid active cand matrix 26 inside.

The matrix itself is immersed in a liquid electrolyte 28 of fused sodium aluminum chloride within the cup-shaped grate 24 .

The housing 20 functions as an anode flow collector;
The cathode current cover 3o is embedded within the matrix 26, protrudes upward from the matrix, penetrates the electrolyte 28, and extends 2° above the housing. It is insulated.

↓ In the present invention, the circle (■) of the cup 24 is covered with graphite felt (not shown), and this is saturated with the liquid electrolyte 28. When cup 24 breaks or breaks, sodium 22 penetrates into the cathode region defined by cup 24 and reacts with the liquid electrolyte of the felt lining according to the reaction equation described above. As a result, it is chlorinated as a reaction product) I
Jum and aluminum are formed in one layer.

This layer is a fiber-reinforced layer of carbon felt.A reaction product layer reinforced with carbon fibers is less likely to be exposed to vibrations or It has been found that the edges are extremely sturdy and do not easily break when subjected to heavy loads.

The applicant has also explored the possibility of filling the entire space of the cathode region occupied by the liquid electrolyte with felt as described above, but over-discharging occurs more quickly, especially in the part of the liquid electrolyte 28 above the cathode matrix 2d. If it is determined that there is too much risk, electrically insulating phinon,
For example, it would be preferable to use ceramic fins, alumina fins, glass phi/ceil, or the like.

Of course, these 7I and 2 are selected to be stable with respect to reaction with the liquid electrolyte. These fiber mats (
When using mat) or wool, these 7-ainons act in part to immobilize the melting component 28, resulting in increased stability. However, from this point of view, the applicant believes that immobilization can be achieved more satisfactorily by using particles in the form of a powder bed saturated with a liquid electrolyte, for example, instead of Phinoζ. .

Similarly, the outer surface of the cup 24 is lined to prevent liquid solute 28 from penetrating into the anode sodium 22 by forming a layer of reaction product reinforced with seven irons on the outer surface of the cup 24. , a layer of suitable fibrous material which is inert towards sodium at the temperature in question may be used.

Alternatively, the entire space of the anode may be filled with such fibrous material.

A similar battery is shown in FIG. Unless otherwise indicated, the same reference numerals as in FIG. 2 represent the same parts as in the battery of FIG.

has been done. 5bC1s is dissolved in this sodium aluminum chloride as an active substance. In this case as well, the present invention can be used in the same manner as in the case of the battery of FIG.

Another object of the present invention is to eliminate the risk of undesirable reactions between the anode material, liquid sodium, and the liquid medicinal material, such as sodium aluminum chloride, when the electrolyte is impregnated into the porous cathode matrix. (in the case of the battery shown in the figure).

At present, the degree of impregnation of liquid electrolyte into MAD 11x is as follows:
The sodium aluminum chloride impregnated into the matrix increases as the effective porosity of the matrix increases, although it is not thick enough to cause a violent reaction between the sodium and the liquid solute impregnated in the matrix. In the event of failure, reactions caused by contact with sodium can increase to problematic levels. As a preventive measure against this phenomenon, similar fins may be added to the matrix's narrow ↑L to reduce the danger. In this case, the phyllocarbons are added during the manufacturing process by mixing, for example, a powder for forming a metal layer with an IJ prior to processing and sintering. The presence of such Phi-Se also helps control the sintering and aids in bonding the cathode matrix in subsequent operations.

It is also possible to use porous artifacts such as mineral sponges or particle beds impregnated by capillary action (possibly sintered) in the same manner as in the above-mentioned phyno, e.g. cup 24.
If used as an internal and/or external lining of a cup or used to completely fill an anode or cathode region, the cup may rupture and allow liquid electrolyte to penetrate into the anode region or cause anode material to enter the cathode region. If permeation occurs, the reaction products will be trapped in a layer at the interface between the artifact or bed and the cup.

As a result, the reaction product layer is immobilized and strengthened, thus improving the ability to separate the liquid electrolyte and the anode. If the artefact or bed contains phynos, fiberization of the reaction product layer can also be achieved.

Although the electrochemical cell according to the invention has been described above with reference to a cylindrical cell with reference to the accompanying drawings, cells of other shapes, for example flat cells, can also be readily produced according to the invention.

[Brief explanation of drawings]

Figure 1 is a side sectional view of a container containing battery components tested by the applicant, Figure 2 is a side sectional view of the battery of the present invention, and Figure 3 is a side sectional view of a container containing battery components tested by the applicant.
The figure is a side sectional view of another battery according to the invention. 10... Appropriate heating container, 12, 22...
...Liquid sodium, 14.28...Liquid sodium aluminum chloride, 16...Reaction product M118...Electrochemical cell, 20...
・Housing, 24...Seno to rotator tsuzo, 26...Cathode matrix, 30...
... Cathode current collector, 32... Mountain insulation part.

Claims (1)

[Scope of Claims] (1) A method comprising two or more reactive components, at least one of which is a liquid at the operating temperature of the battery, and in which these components are separated from each other and potentially preferred. may react with each other to form one or more reaction products which are inert to these components, at least one of which is liquid at the operating temperature. impregnated with or comprising a macroporous material, the macroporous material enhancing and/or reinforcing the reaction products in one or more regions where contact between the reaction components can occur An electrochemical cell, characterized in that it is equipped to improve the ability to capture and thereby separate the components of the reaction product from each other. (2) The battery according to claim 1, wherein the porous material is a particulate material. (3) the porous material has a density different from the density of the reactant components with which it comes in contact and occupies a portion of the space occupied by the components, so that at the operating temperature of the cell there is a The 'α pond according to claim 2, wherein the layer of porous material is formed. (4) The battery according to claim 1, wherein the particles of the porous material are held in contact with each other. (5) The battery according to claim 1, wherein the porous material is in the form of an artificial object. (6) The battery according to claim 5, wherein the artificial object is made of a textile or felt-like fibrous material. (7) The battery according to claim 5, wherein the artificial object is a sintered artificial object. (8) The porous material allows components that come into contact with the material at cell operating temperatures to freely diffuse through the material. Claims 1 to 7A7 having a porosity such as
The battery described in any of the paragraphs. (9) The two reactive components of the battery are in liquid form at the operating temperature of the battery and are separated from each other by a separator. Claims 1 to 8, wherein at least one side is further provided with the porous material at the interface between the component and the separator on the same side.
battery. (10) The battery according to claim 9(b), wherein the separator is a solid electrolyte, and the components on both sides of the separator are an anode material and a liquid electrolyte material, respectively. (1) The battery according to claim 10, wherein the layer is provided at an interface between a solid electrolyte and a solid electrolyte. The anode material is composed of an alkali metal and/or alkaline earth metal, the liquid electrolyte is a molten salt electrolyte containing one or more alkali metal and/or alkaline earth metal halides, and 12. A battery according to claim 10 or 11, wherein the layer consists of a non-conductive fibrous material. ↓ 03) An electrochemical cell substantially as described and illustrated herein. ■ Electrochemistry in which at least one component is in liquid form at the operating temperature of the cell and is separated from each other but can react with each other to form inert reaction products with potentially undesirable consequences. A method for reducing the potential hazards created when two or more reactive components of a commercial battery come into contact with each other, the method comprising: strengthening and/or trapping said reaction products, thereby making said components mutually A macroporous material impregnated with or included in at least one reaction component, in order to improve the ability of said reaction products to separate into molecules, in which contact between the reaction components can occur. (15) At least one component is in liquid form at the operating temperature of the cell and is separated from one another but does not react with potentially undesirable consequences. A method for reducing the potential hazards created when two or more reactive components of an electrochemical cell come into contact that may together form an inert reaction product, comprising: Methods described and illustrated.