CN1018122B - Improved alkali metal battery - Google Patents

Abstract

A method of forming an air seal for a safety reservoir of a sodium, sulfur cell is disclosed whereby overpressure can be used to force sodium through a hole in the bottom of the reservoir to wet the active area around the reservoir. The sealing means is also structurally advantageous.

Description

Improved alkali metal battery

The present invention relates to a kind of alkali metal battery, it comprises that an outer container connects the same solid electrolyte member that internal tank is divided into anode region and cathodic region.The anode region comprises a kind of molten alkali metal, and most typical is sodium: it is liquid suitable cathode reactant equally that the cathodic region comprises a kind of, and most typical is sulphur and sodium polysulfide.

We know, this alkali metal battery can be by the solid electrolyte member that is positioned at outer container likeness in form cup-shaped, and are included in the alkali-metal anode in the electrolyte cup and are included between cup and outer container the anode reactant in the perimeter and form.Outer container, most typical is to make with metal, and forms a cathode collector.The collector component of the electron conduction by placing cup, it can with stay any alkali metal in the cup and keep in touch electric current with the alkali-metal anode in the electrolyte cup of collecting, and the cover that passes an electrolyte cup stretches out, thereby an electric current exit is provided.

An example of this alkali metal battery is that the form with sodium/sulphur battery is shown in GB-A-2161017.

We also know, in order to improve the performance of alkali metal battery, can or load onto an additional tubulose sheet metal tightly adjacent with the inner surface of electrolytic tube in containing the electrolyte cup of alkali-metal anode in the pipe.The making of this tubular sheeting can be rolled into a flat spring thin slice earlier pipe and realize that the elasticity of this thin slice then makes it tightly to be attached on the electrolytical cylindrical inner wall before it inserts the electrolyte cup-shaped.

In this purpose of tubular metal thin slice be to make molten alkali metal can be in maximum magnitude moistening electrolytical cylindrical surface.Can recognize that when battery discharge, alkali metal (typically, the being sodium) amount in electrolyte cup or pipe reduces, the electrolyte meter area that causes directly contacting with alkali metal reduces.Thereby cause when battery discharge, its internal resistance increases.Yet, place the tubular metal thin slice of electrolyte cup or pipe to make the narrow seam of liquid base metal between the cylindrical inner wall of thin slice and pipe be picked up owing to capillarity, thereby increase by moistening electrolytical surface area, make the internal resistance of cell remain a low value.An example of above-mentioned structure is open in GB-A-1461071.

The employed solid electrolyte of alkali metal battery is made by ceramic material usually, though this material electric insulation can conduct alkali-metal cation.The sodium galvanic battery material that adopts usually is βYang Hualv (beta alumina).Using another problem that this battery produced of ceramic electrolyte is the possibility that electrolyte breaks down, as, break etc., thereby make anode directly contact and mix with cathode material.Any this direct mixing all can cause exothermic reaction consumingly, if this reaction do not check out, can cause the temperature of battery to raise, make the outer container of battery break.This can cause product seepage in the battery pack cavity that comprises a plurality of battery cells of strong corrosion conversely again.

Done a large amount of effort although have the electrolytic component of very high integrality for preparation, thereby the danger that damage fault battery occurred drops to low-down level, but some danger still exists, and should make great efforts greatly to eliminate the danger of this calamity inefficacy that still exists.

As an example, GB-A-1517287 has described a kind of sodium-sulphur battery, and it is mounted with a molybdenum pipe as the sodium holder in the electrolytical inboard of tube-type solid.The molybdenum pipe limits a thin core zone sodium together with electrolytic tube and is subjected to capillarity and flows through this thin core zone.Another blind end at the molybdenum pipe has an aperture, makes sodium to enter thin core zone from the sodium holder, and the size in hole allows the flow velocity of sodium to adapt to designed battery discharge and charging requirement just.Yet all these arrange still and especially to fill anode region and alkali metal holder aspect filling battery, and have some problems aspect anode region and the holder closing and seal.

With reference to GB2162680, the alkali metal holder that a hermetic seal is wherein arranged in the tubular ceramic electrolyte of alkali metal battery, some aperture of the bottom of holder is by applying the inboard that overvoltage can make the alkali metal electrolytic tube of fully wetting close holder under capillarity in the holder to holder.Structurally, the filling pipe on holder top passes the hole with the airtight pottery of electrolytic tube, and is filling the current-collector of realizing hermetic seal on the pipe and becoming galvanic anode.

In addition, from GB1519451, can see by filling pipe applying the situation of overvoltage in the holder, wherein electrolyte is cup-shaped, playing capillary parts is a kind of and contacted wick of electrolyte or line screen section, also can be the tubular solid components that keeps a capillary space with electrolyte.

According to the present invention, a kind of alkali metal battery comprises: an outer container, one is positioned at this container and container is divided into solid electrolyte cup in the anode region of cup and the cathodic region outside cup, and one be contained near the alkali metal holder in the electrolyte cup so that an active region to be provided, thereby restriction alkali metal directly is exposed to the quantity of electrolyte cup inner surface.Holder comprises the circulation device that makes alkali metal can flow to the active region from holder, it is characterized in that: it has electric insulation ceramics cover and a kind of device that can apply overvoltage in manufacturing process to holder inside that a sealing electrolyte cup has an aperture, this device comprises a hermetic seal between holder and ceramic shield, thereby realizes and inner airtight contact of holder by the aperture on the cover.Get in touch by realization and the airtight of holder inside, be easier in battery, fill molten alkali metal.Filling in the molten alkali metal process to holder, or filling when finishing, will produce an overvoltage in the holder, filling and abundant wetting its surface by the active region of circulation device between electrolyte cup and holder to force alkali metal.If in holder, there is not such overvoltage, the surface of active region then, the surface that exposes of solid electrolyte particularly, it is wetting just to be not easy to be melted alkali metal, thereby stops from holder by the circulation device desirable capillarity that the alkali metal sucking-off is required.

In one embodiment, the opening of holder has a wall that extends under ceramic shield, have on it one with the cover on an aperture opening point-blank.Hermetic seal comprises that provides a device that is tightly connected, and it extends to aperture on the cover at least from opening.Be to provide the device that is tightly connected to be one and fill pipe easily.Here used filling pipe term is not limited to the pipe of cylindricality or circular cross-section, and is meant the device that any permission material passes through.A fibre core also can be set in the active region, make alkali metal can be by circulation device by capillarity by sucking-off from holder.In another embodiment, can select the size of holder to make the active region enough narrow, so that alkali metal is picked up by capillarity.Fill pipe and can directly pass aperture on the ceramic shield, and this pipe and holder all conducts electricity and electrical connection mutually, thereby the current-collector of a galvanic anode formed.

In another embodiment, the filling pipe only partly passes the aperture on the ceramic shield and is closed therein.Then, battery can comprise an anode collector pin, and it passes above-mentioned aperture and fills pipe, contacts with molten alkali metal in the holder.In this embodiment, fill preferably flexible metal sleeve rivet of pipe.On the other hand, this pipe and holder all conduct electricity and are electrically connected mutually, and battery can comprise a conductive connector, and it passes aperture and is electrically connected with this pipe.This binding post has a inner, and a cavity that comprises the heat expansion material is housed, and is expanded in this inner, forms a kind of pressure with the filling pipe and contacts.Holder is made with filling pipe available metal.

In the former enforcement, filling pipe and the rigidly connected this assembly of holder be used for interfixing electrolyte cup and insulating ceramics cover, so that it two is closed in together.Holder is installed near electrolyte cup inboard, fill pipe and pass and fix the insulating ceramics cover, thereby cup and cover is fixed on appropriate position so that with the method as glazing they are enclosed in together.But owing to be used to make the size that the roasting technique of electrolyte cup can't accurately be made the cup of duplication of production, therefore, be necessary the outward flange of each electrolyte cup is processed near its openend, so that carry out automatic screening with covering.Electrolyte is not only hard but also crisp, therefore processes both difficult and expensive.But,, can avoid this processing according to described assembling.

On the other hand, the invention provides a kind of method of making a kind of alkali metal battery, this battery has: an outer container, the two-part solid electrolyte cup in anode region and the cathodic region outside cup that in container, container is divided in cup, and electric insulation ceramics cover that is fixed on around the margin of optic cup, an aperture is arranged on this cover, also has an alkali metal holder in this external electrolyte cup so that between electrolyte cup and holder, form an active region, circulation device makes metal can flow to the active region from holder, this method may further comprise the steps: provide to holder inside by 1 aperture on the insulating ceramics member to be tightly connected, by above-mentioned connection molten alkali metal is imported holder, thereby in holder, provide an overvoltage to fill and sealing anode region, fully wetting above-mentioned active region with the circulation device that forces molten alkali metal to pass through in the holder.

Be that holder had just completely cut off with ceramic component before importing alkali metal by being tightly connected easily.In addition, overvoltage can also be by finding time the anode region before importing alkali metal and then the holder internal pressurization being produced.

Now, embodiments of the invention are described with reference to the accompanying drawings, wherein:

Fig. 1 is a sectional view of implementing a kind of sodium-sulphur battery of the present invention;

Fig. 2 and Fig. 3 are the detailed sectional view of each parts of battery;

Fig. 4 is the sectional view of another embodiment of the present invention;

Fig. 5 represents to assemble the method for battery part shown in Figure 4; And

Fig. 6 is the improved detailed sectional view of battery shown in Figure 4.

With reference to Fig. 1, generally, sodium-sulphur battery is cylindrical, vertically represents with cylinder axis among the figure.This battery has a metal outer container 10, and most typical is that its inner plating is with the cathode reactant of mild steel with the opposing battery, sulphur/sodium polysulfide.This battery is equipped with the interior pipe 11 formation electrolyte cups that a βYang Hualv is made.Electrolyte cup 11 is in the top by an insulating material, and the most typical cap 12 that is alpha-aluminium oxide (alpha alumina) is made covers.Cap 12 is sealed by glazing and electrolyte cup 11.Negative electrode seals 13 and is made by the endless metal thin slice, and the most frequently used is Fu Kelelaoyi alloy or Yin Kenei alloy (Fecralloy or Inconel) is with the corrosion of the cathodic region inner cathode reactant material between opposing electrolyte 11 and the container 10.The openend that seals 13 outward flange and container 10 is welded together, inner edges by hot binding 14 and with the upper surface sealing-in of cap 12.

The annular space 15 in limiting battery cathodic region in fully charged battery, is filled to soak into the conductive felt of sulphur, and sulphur about 350 ℃, is liquid under the working temperature of battery.

The inside of electrolyte cup 11 forms an anode region 16, and in this embodiment of the present invention, it comprises the holder 17 that can be made by mild steel.Holder 17 generally is cylindrical, its size should be close to cup 11 just, between the inner surface of holder 17 and cup 11, only reserve a narrow space or be called the active region, be enough to make the skim molten sodium to be picked up and fill this narrow space by capillary force.

Fill pipe 18 and be welded on the aperture at holder 17 tops forming a hermetic seal, and pass the hole 19 that cap 12 is provided with.

The anode region of battery is by annular flake member 20, and this thin slice 20 equally also is to make with Fu Kelelaoyi alloy or Yin Kenei alloy, and by hot binding on 21, and with cap 12 sealing-ins, just be positioned at the cathodic region and seal within 13 the envelope point 14 but separate with it.A metal washer 22 is welded in the top surface of annular construction member 20, and successively along the part welding of inner edges with the filling pipe 18 that passes cap 12.

When assemble, fill pipe 18 and be welded on the holder 17.Then, holder is installed in the electrolyte cup 11, and cap 12 is installed in fills on the pipe 18.As can be seen, fill pipe 18 and holder 17 and effectively cap 12 is fixed on the openend of cup 11, need not process cup thereby these members can be enclosed in together by glazing.

Fill pipe 18 and can extend on the battery end face, until point 23 places as shown in the figure.In order to fill battery, molten sodium can pipe 18 adds in holder 17 and when battery operated, molten sodium is picked up to be filled in narrow space or the active region between holder and the electrolyte cup by capillarity by the aperture 24 in the holder bottom by filling.Yet, the surface of electrolyte that limits the active region and holder begin to be melted sodium wetting before, capillary force also is not enough to sodium is picked up by aperture 24.Therefore, filling the close connection of pipe 18 enterprising promoting the circulation of qi, producing an overvoltage and enter the active region in that holder is inner to force sodium, fully wetting should the surface.Can be by before adding alkali metal, being found time in the anode region, and then the holder internal pressurization is produced overvoltage.After this and when in holder 17, filled with sodium, can be in the drawings 25 pinches go to fill and manage 18 tops, and close holder and anode region.Filling pipe top 18 just scraps then.

Can mean and arrive to have three functions at the indoor metal holder 17 of galvanic anode.Because holder is to be made of metal and to be welded on the filling pipe 18 that passes the battery top, it has the current-collector effect of galvanic anode.In addition, the narrow gap between holder 17 and electrolyte cup 11 inner surfaces has been guaranteed all basically electrolyte inner surfaces together with the aperture 24 of holder bottom, when using continuously, even work as battery discharge, when the sodium liquid level in the holder itself reduced, it was wetting still to be melted sodium.

Yet, importantly, holder 17 and aperture 24 thereof have also limited the quantity of the sodium that can directly contact with any cathode reactant of bleeding from electrolyte cup 11 in failure accident, have only the sodium that around holder 17, forms thin layer of a little volume to react with the sulphur of coming in/sodium polysulfide immediately, may cause the amplitude that temperature rises thereby limited greatly because of electrolyte breaks down.Therefore, the fresh sodium that reacts with the sulphur that infiltrates/sodium polysulfide can only provide according to the determined speed of the flow that flows through aperture 24, and flow then is limited in the required value of the maximum under normal operation discharge rate of battery.

Therefore, above-mentioned novel structure has increased the fail safe of battery under the situation that electrolyte breaks down greatly, simultaneously the assembling of battery is more prone to, particularly the filling of sodium and providing.Anode and cathode material are separated fully to prevent that the undesirable temperature that may damage battery outer container 10 from rising.

Holder bottle shown in Figure 1 can be by two open cup, and mouth to mouth, middle to insert disk that perforation arranged welded together and make.Disk forms a central horizontal dividing plate in bottle, constitute holder, and the position of the perforation on the dish makes molten sodium to pass along any direction of battery.

According to top structure, the holder bottle can be made of very thin mild steel.The disk that inserts helps operation when not only two open cup being welded together with the formation container, and can increase the intensity of made bottle greatly.

Referring now to Fig. 2 and Fig. 3, they have shown implements battery of the present invention concrete improvement structurally.

Fig. 2 is a detailed sectional view, and it is illustrated in the sodium holder inside that comprises Liquid Sodium 40 and comprises the carbon felt and the hierarchical structure between the cathodic region outside the solid electrolyte wall of cup 42 41 of soaking into sulphur.Reservoir wall preferably is made up of mild steel shown among the figure 43, is fixed on its outer surface with the thin graphite flake 44 of one deck.The mild steel wall opposing that graphite flake can make holder is because of the break down corrosion of any sodium polysulfide that zone between holder and electrolyte occurs of electrolyte.

Be that the narrow space 45 between reservoir wall 43 and solid electrolyte 42 has been full of alumina fibre easily.This fiberfill can further provide wick effect, thereby guarantees fully to scatter from the sodium of holder, with the whole interior cylindrical surface of wetting electrolyte cup, and also can serve as the absorber of wiping impurity in the sodium in addition.

Can constitute circulation device near the structure around the aperture of reservoir receptacle bottom, shown in Fig. 3 is detailed.Corresponding parts shown in Figure 3 use same number designation.A nickel sheet 46 is fixed on aperture 24 as shown in the figure.Because it is wetting that nickel is easy to be melted sodium, therefore, the nickel sheet helps molten sodium initially to pass through aperture.

An alternative embodiment of the invention as shown in Figure 4, wherein corresponding parts still be marked with Fig. 1 in same number designation.In the embodiment shown in fig. 4, have one to fill pipe 50, it only passes alpha-aluminium oxide cap 12 and extend a part in aperture 19.Fill pipe 50 and be enclosed in holder 17 firmly, and also be enclosed within the aperture 19, thereby produce airtight linking to each other with holder 17 inside by aperture 19 outer ends are tightly connected.

Directly do not pass aperture 19 because manage 50, therefore, a special device must be set to collect from the electric current of anode material.Settle a current-collector pin 51 to pass aperture 19 and fill pipe 50 and extend downwards, so that it contacts with any molten sodium in staying holder 17.Thereby current-collector pin 51 welds the anode region of closing battery mutually along its head 52 and packing ring 22.A sponge grease 70 is arranged in holder bottom, steel preferably, it contacts with the end of current-collector pin 51, even to guarantee that excellent electric contact is also arranged when the low sodium liquid level.

For assembling embodiment shown in Figure 4, can utilize axle riveting technology shown in Figure 5.Reservoir receptacle 17 at first is fixed within the electrolyte cup 11, seals then with alpha-aluminium oxide lid 12, to seal this cup.Reservoir receptacle 17 is made a call to a hole on its top, its arrangement should be corresponding with the aperture 19 on the cover 12 with size.Sleeve or the lasso that manufacture axle riveted joint utensil and flexible metal are installed together, this sleeve or lasso are installed in filling pipe 50 on the axle 53 with formation, then thereby axle and sleeve are inserted aperture 19 fixed muffles, this sleeve passes the aperture of container 17 as shown in Figure 5 and partly upwards stretches in the aperture 19 of ceramic cap 12.A liner 54 is fixed on the riveted joint utensil easily to guarantee the correct location of sleeve 50.Operate this utensil then axle 53 is extracted out by sleeve 50, thereby make sleeve 50 correctly fix this utensil near liner 54.Along with 55 of axle 53 is drawn out of sleeve 50, this sleeve stretches out, and provides a wiper seal in the inwall of the aperture 19 of the aperture of container 17 and 12.

Fig. 6 represents the correction of battery shown in Figure 4, and it is that battery is along the detailed sectional view of filling pipe 50 peripheral regions.Here use one to connect binding post 60 to replace directly penetrating holder and wherein the contacted current collection pin 51 of molten sodium, this binding post 60 has a stature 61, is being supported it and the packing ring anode region with closing battery welded together by packing ring 22.It is the same that the degree of depth that binding post stretches into the anode region only stretches into the degree of depth of holder 17 inside with the openend of filling pipe 50.The inner of binding post 60 is hollow, forms cavity 62 these cavitys and is full of the heat expansion material, and the most frequently used is gas or liquid.In the time of in binding post 60 begins to be fixed on aperture 19, cavity 62 does not expand, thereby binding post can easily slip in the filling pipe 50 by diagram.Heating battery and binding post 60 rise to high temperature, and as the working temperature of battery, cavity 62 is owing to the material that is wherein comprised expands, and form firm electrically contacting with the inside of filling pipe 50.As a result, binding post 60 forms with reservoir receptacle 17 and is electrically connected, thereby need not establish current-collector in the anode region in addition.

Claims (14)

1, an alkali metal battery comprises: an outer container, a solid electrolyte ring, it is divided into container anode region in cup and the cathodic region outside the cup in container, and alkali metal holder, near the inboard of electrolyte cup so that an active region to be provided, thereby restriction directly is exposed to the alkali metal amount of electrolyte cup inner surface, the alkali metal holder comprises circulation device, this device makes alkali metal flow to the active region in holder, electric insulation ceramics cover and a hole of a sealing electrolyte cup, wherein have between holder and the ceramic shield and be tightly connected so that be tightly connected by hole in the ceramic shield and holder inside, above-mentioned connection extends to above-mentioned hole and fill pipe as one during battery constitutes from above-mentioned holder at least, and applies overvoltage during battery is made in holder.

It is characterized in that: holder has a wall that extends under ceramic shield, and it is in alignment to have an opening and above-mentioned hole on the reservoir wall; And provide airtight binding by a flexible metal lasso rivet.

2, alkali metal battery according to claim 1, wherein rivet just partly passes hole and sealed therein.

3, alkali metal battery according to claim 2 comprises an anode current collection pin, thereby it passes above-mentioned hole and fills pipe and extend with molten alkali metal in the holder and contact.

4, alkali metal battery according to claim 1, wherein fill pipe and holder and be conduction be electrically connected, and comprise that a conduction connects binding post, it passes the hole and fills the pipe electrical connection.

5, alkali metal battery according to claim 4, wherein binding post has a inner that is connected with the cavity that contains thermal expansion material, so that inner the expansion contacts with filling pipe formation pressure.

6, alkali metal battery according to claim 1, wherein, holder is made by mild steel, and covers with graphite foil at its outer surface.

7, according to the described alkali metal battery of claim 1, wherein, the alumina fibre material is contained in the active region between holder and electrolyte cup provides a fuse to help capillarity.

8, alkali metal battery according to claim 3 wherein, has a kind of biscuit to be used for guaranteeing replenishing anode current when the sodium liquid level is low in the bottom of holder.

9, a kind of method of making alkali metal battery, comprise the following steps, an outer container is provided, solid electrolyte cup in said vesse, it is divided into an interior anode region of cup and the outer cathodic region of cup with container, and one wherein has the electric insulation ceramics cover in a hole to be combined on the edge of cup, in addition, the alkali metal holder is housed to form an active region between electrolyte cup and holder in the electrolyte cup, holder has a flow device to allow metal to flow to the active region in holder; Seal electrolysis cup with ceramic shield;

By a connection holder and ceramic component are sealed, this is connected in the battery manufacturing process and fills pipe as one, fill pipe and extend to the hole at least, and provide one to be tightly connected to holder inside by the hole on the insulating ceramics parts from holder.

Introduce the alkali metal of fusion to holder by above-mentioned connection;

In holder, provide an overvoltage with the alkali metal that forces fusing by the circulation device in the holder to fill and moistening above-mentioned active region fully, seal the anode region then;

It is characterized in that the following step is arranged: produce a hole in holder, this hole is corresponding to the hole on the ceramic shield and in alignment with it;

And the step that holder and ceramic component are sealed together comprised: the major part of flexible metal lasso rivet is installed on the axle, with hole and the holder on the lasso introduced cover on the axle, extract axle out lasso then, thereby the head of axle extends lasso to be made it to draw with holder and ceramic shield pressure and touches.

10, the method for manufacturing alkali metal battery according to claim 9, wherein before introducing alkali metal by sky is drawn in the anode region, pressurization produces overvoltage in holder then.

11,, wherein, fill and manage the aperture extension of only partly passing in the cover according to claim 9 or 10 described methods; And provide the step that is tightly connected to comprise and to fill the step of duct occlusion in aperture.

12, method according to claim 11 is wherein filled pipe and anode region and is finally sealed by fastening the closing cock in the aperture in the ceramic shield.

13, method according to claim 12, wherein closing cock is to be made of electric current current collection pin.

14, method according to claim 12, wherein, closing cock is made of metal and has outer end and a inner isolated with cover, the inner has the cavity of dress thermal expansion material, wherein, when filling after pipe and anode be closed, battery is heated, and is expanded in the inside of binding post to constitute to manage pressure inside with filling and contact.

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