CN107768680B

CN107768680B - Liquid metal battery negative current collector structure and assembling method thereof

Info

Publication number: CN107768680B
Application number: CN201710930477.3A
Authority: CN
Inventors: 郭姣姣; 王康丽; 彭勃; 张坤; 蒋凯; 李侠; 王玉平
Original assignee: China XD Electric Co Ltd
Current assignee: China XD Electric Co Ltd
Priority date: 2017-10-09
Filing date: 2017-10-09
Publication date: 2020-09-01
Anticipated expiration: 2037-10-09
Also published as: CN107768680A

Abstract

The invention discloses a liquid metal battery negative current collector structure and an assembling method thereof, wherein the liquid metal battery negative current collector structure comprises a current collector rod, a porous metal plate, foam metal and a trident gasket; the current collector rod is connected with the porous metal plate, the foam metal is clamped between the porous metal plate and the three-fork gasket and attached to the porous metal plate and the three-fork gasket, and the three-fork gasket is connected with the current collector rod through the conductor fastener. The structure solves the technical problems of physical and chemical stability of the liquid metal battery at normal temperature and high temperature, optimization of battery reaction rate and current collection efficiency, reduction of internal impedance of the battery and the like.

Description

Liquid metal battery negative current collector structure and assembling method thereof

Technical Field

The invention belongs to the technical field of energy storage batteries, and relates to a liquid metal battery negative electrode current collector structure and an assembling method thereof.

Background

The liquid metal battery is a novel secondary battery for power grid level energy storage application. The negative electrode of the battery is generally a simple substance or alloy of alkali metal or alkaline earth metal, and the positive electrode is generally a transition metal simple substance, alloy or other compound which can form alloy with the negative electrode and has a certain potential difference with the negative electrode. The electrolyte is an inorganic salt corresponding to the negative electrode metal or a mixture thereof. When the battery is operated, the metal electrode and the inorganic salt electrolyte thereof are melted into liquid at high temperature and automatically delaminate according to the density difference. During discharge, the negative metal loses electrons and works through an external circuit. After ionization, the metal of the negative electrode is transferred to the positive electrode through molten salt and is alloyed with the metal of the positive electrode. When charging, the battery performs the reverse process. Through the alloying and dealloying processes, the liquid metal battery can complete the storage and release of electric energy, and realize the energy exchange with the outside.

In the process of storing and operating the liquid metal battery, the current collector structure in the battery cannot chemically react with materials and gases in the battery. This is because, on the one hand, the occurrence of chemical reaction may cause corrosion of the battery structure, resulting in detachment of the battery negative electrode current collector from the negative electrode material and the electrolyte material, failing to perform current collection and transmission functions, and thus causing battery failure; on the other hand, chemical reaction with the internal material may cause deterioration of the active material inside the battery, possibly resulting in degradation or even failure of the battery performance. It is therefore important to maintain the physical and chemical stability of the cell structure during storage and operation.

The negative electrode material in the liquid metal battery is high-temperature molten metal and has good fluidity, and the battery shell generally adopts a metal or alloy structure, so that the contact of the two necessarily causes the short circuit of the battery. That is, it is necessary to design a structure capable of confining the molten metal without contacting the battery case; the constraint structure needs to have enough contact area with the current collector rod so as to reduce the internal contact resistance of the battery; in order to increase the reaction rate of the electrode material, the contact area between the negative electrode material and the current collector should be increased as much as possible; in addition, the negative electrode current collector is a protruding structure inside the battery, and needs to have good physical stability so as to avoid contact with the case or the positive electrode material inside the battery and provide stable current.

At present, liquid metal batteries are not yet industrialized; in the prior patent, a solid negative current collector is partially adopted and a boron nitride ceramic tube is used for preventing the contact between a battery negative material and a shell, but the structure can cause the increase of the weight of the battery on one hand, and on the other hand, the contact area between the negative material and the negative current collector is limited, and the reaction rate is severely restricted; the method for binding the negative electrode material by using the foam metal is also provided in the earlier stage of the project group, but the foam metal cannot be welded with the current collector rod due to the limitation of the structure and the material, so that the foam metal is fixed by using a manual mode of penetrating the foam metal by using iron wires, the sizes, the directions and the lower ends of prepared battery perforations are kept with iron wire bulges which are all inconsistent, and the consistency of the prepared battery monomer is poor. It is well known that uniformity of cell performance is critical to cell grouping and systematization, and therefore, this structure is not always the structure adopted in the industrial production of liquid metal batteries.

The novel negative current collector structure design is carried out on the liquid metal battery, the physical and chemical stability of the liquid metal battery at normal temperature and high temperature is solved, the reaction rate and the current collection efficiency of the battery are optimized, the internal impedance of the battery is reduced, and a novel negative current collection technology is provided.

Disclosure of Invention

The invention aims to provide a liquid metal battery negative current collector structure and an assembling method thereof, which solve the technical problems of physical and chemical stability of a liquid metal battery at normal temperature and high temperature, optimization of battery reaction rate and current collection efficiency, reduction of internal impedance of the battery and the like.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a liquid metal battery negative current collector structure comprises a current collector rod, a porous metal plate, foam metal and a trident gasket; the current collector rod is connected with the porous metal plate, the foam metal is clamped between the porous metal plate and the three-fork gasket and attached to the porous metal plate and the three-fork gasket, and the three-fork gasket is connected with the current collector rod through the conductor fastener.

The bottom of the current collector rod is provided with an inner screw hole, and the conductor fastener is a screw; the end part of the screw penetrates through the three-fork gasket and the foam metal in sequence and is in threaded connection with the current collector rod.

The porous metal plate is provided with a plurality of holes, and the central hole of the porous metal plate is used for installing a fluid collecting rod.

The three-fork gasket is composed of a circular ring and three forks arranged in the circular ring, the central connection part of the three forks is bent upwards to form a protrusion with a rib, the center of the protrusion is provided with a central hole, and the lower end of the bent part forms a groove for installing a conductor fastener.

The foam metal is provided with a central through hole for penetrating through the conductor fastener, the center of the bottom surface of the foam metal is provided with a recess for mounting and limiting the rotation of the three-fork gasket, and the shape of the recess is matched with that of the protrusion.

The current collector rod, the porous metal plate, the foam metal, the conductor fastener and the three-fork gasket are coaxially arranged.

The current collecting rod, the porous metal plate, the screw and the trident gasket are made of stainless steel, oxygen-free copper or titanium alloy materials; the foam metal is made of Al, Cu, Ni, NiCrFe, ZnCu, NiCu, NiCrW, NiFe or alloy material.

When the current collector rod is made of oxygen-free copper or titanium alloy, a corrosion-resistant material is adopted to coat the current collector rod and form tight fit, and the corrosion-resistant material is welded with the porous metal plate; when stainless steel is used for the collector bar, the collector bar is directly welded to the porous metal plate.

An assembling method of a liquid metal battery negative electrode current collector structure comprises the following steps:

1) nesting the current collector rod with an inner hole of the porous metal plate, and welding and fixing;

2) attaching the upper surface of the foam metal to the lower surface of the welded porous metal plate, attaching the three-fork gasket to the lower surface of the foam metal, and fastening the four parts by using a conductor fastener to sequentially penetrate through the three-fork gasket and the foam metal and be connected with a current collector rod.

Compared with the prior art, the invention at least has the following technical effects:

the invention positions the foam metal in the axial direction and the horizontal direction through the conductor fastener and the current collector rod, and the protrusions on the three-fork gasket are used for limiting the rotation of the foam metal in the horizontal direction; the parallelism of the foam metal is controlled by parallel extrusion of the porous metal plate and the three-fork gasket, and the stress deformation of the foam metal is reduced. The structural design of the negative current collector adopts a mode of assembling foam metal by a machining structure to adsorb liquid metal or alloy, so that the liquid metal or alloy can be effectively bound in the current collector, and the contact between the liquid metal or alloy and a battery shell is avoided; and the contact area between the negative electrode metal or alloy and the negative electrode current collector is greatly increased, and the reaction rate of the negative electrode of the liquid metal battery can be effectively improved. The physical and chemical stability of the liquid metal battery at normal temperature and high temperature is improved, the reaction rate and the current collection efficiency of the battery are optimized, and the internal impedance of the battery is reduced.

Furthermore, the connection between the foam metal and the current collector rod can be effectively realized by adopting a screw fixing mode, and the connection can be completely finished by adopting a standard component, so that the error caused by manual fixing is greatly reduced; in order to improve the current transmission rate of the foam metal and the current collector rod as much as possible and reduce the internal resistance, a porous metal plate is specially designed to be fixed on the upper surface of the foam metal. The screw plays a role in longitudinally fixing the foam alloy, and the three-fork gasket plays a role in axially fixing the foam alloy.

Further, the structural design of the trifurcated spacer aims to realize the axial control of the foam metal and minimize the surface area of the foam metal so as to reduce the influence of the foam metal on the adsorption metal or alloy to the maximum extent.

Drawings

FIG. 1 is a schematic view of the charge and discharge curves of an assembled battery;

fig. 2 is a schematic view of a current collector rod with internal threaded holes;

FIG. 3 is a schematic view of a perforated metal sheet;

FIG. 4 is a schematic view of a metal foam;

FIG. 5 is a schematic view of a screw;

FIG. 6 is a schematic view of a trifurcated shim;

fig. 7 is a schematic view of an assembled negative current collector.

Wherein, 1 is the mass flow body pole of in-band screw, 2 is porous metal sheet, 3 is foam metal, 4 is the screw, 5 is trident gasket, 6 is sunken, 7 is the arch, 8 is the trident.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The following are respectively described in terms of apparatus structures and methods:

referring to fig. 1-5, a negative current collector structure of a liquid metal battery according to the present invention includes a current collector rod 1 with an internal screw hole, a porous metal plate 2, a foam metal 3, a screw 4, and a trident spacer 5. The inner screw hole of the fluid collecting rod 1 is matched with the screw 4; the outer diameter of the collector bar 1 is matched with the diameter of the central circle of the porous metal plate 2; the diameter of the cylindrical channel in the foam metal 3 is matched with that of the screw 4; the diameter of the inner circular hole of the three-fork gasket 5 is matched with the screw, and the groove is matched with the nut.

The current collector rod 1, the porous metal plate 2, the foam metal 3, the screw 4 and the trident gasket 5 are coaxially designed; the current collecting rod 1, the porous metal plate 2, the screw 4 and the trident gasket 5 are made of stainless steel, oxygen-free copper or titanium alloy materials; the foam metal 3 is made of metal or alloy materials such as Al, Cu, Ni, NiCrFe, ZnCu, NiCu, NiCrW, NiFe and the like.

When the current collector bar 1 of oxygen-free copper or titanium alloy is used, the current collector bar 1 is coated with a stainless steel tube and a tight fit is formed; at this time, the stainless steel pipe is firmly welded to the porous metal plate 2. When the stainless collector bar 1 is used, the collector bar 1 and the porous metal plate 2 are directly and firmly welded;

the foam metal 3 is axially and horizontally positioned by a screw 4 and a current collector rod 1 with an internal screw hole, and the foam metal 3 is limited to rotate in the horizontal direction by a bulge on a three-fork gasket 5; the parallelism of the foam metal 3 is controlled by parallel extrusion of the porous metal plate 2 and the trifurcate gasket 5, and the stress deformation of the foam metal 3 is reduced.

The current collector rod 1 and the inner hole of the porous metal plate 2 are nested and are coaxially welded by adopting a laser welding or argon arc welding mode.

The upper surface of the foam metal 3 is tightly attached to the lower surface of the welded porous metal plate 2, the three-fork gasket 5 is tightly attached to the lower surface of the foam metal 3, and the four are fastened by screws matched with the inner screw holes of the fluid collecting rod 1.

The preparation method of the negative current collector structure comprises the following steps:

1) the current collecting rod 1 and the inner hole of the porous metal plate 2 are nested and welded by adopting a laser welding or argon arc welding mode, so that the two are coaxial.

2) With the laminating of 3 upper surfaces of foam metal and the 2 lower surfaces of porous metal sheet that weld, the gasket 5 of special design and the laminating of 3 lower surfaces of foam metal utilize with the current collector pole in the screw assorted with fasten four, the dynamics can not be too big in order to avoid the damage of foam metal 3.

Referring to fig. 1, the negative electrode current collector structure provided by the present invention is processed according to the illustration, and the steps are as follows:

firstly, welding one end of a cathode current collector rod with an inner screw hole in the graph 2 and the porous screen plate in the graph 3 together by adopting argon arc welding or laser welding to ensure that the two ends are coaxial;

secondly, placing the foam metal part in FIG. 4 and the porous metal plate in FIG. 3 coaxially;

thirdly, inserting the protrusion 7 of the three-fork gasket 5 and the foam metal joint gasket of the figure 6 into the recess 6 matched with the foam alloy;

fourthly, screwing the screw in fig. 5 into the negative pole current collector rod in fig. 2 through the gasket in fig. 6, the foam metal in fig. 4 and the porous metal plate in fig. 3 to enable all the components to be tightly matched, and remembering that the screw cannot be too forcefully violent so as to avoid damaging the structure of the foam metal.

By adopting the negative current collector structure of the invention and adopting the foam metal to adsorb the liquid metal or alloy, the effective constraint of the liquid metal or alloy is realized, the contact between the liquid metal or alloy and the conductive shell of the battery is avoided, and the reaction rate of the negative electrode material is improved; adopt the screw fixation mode, effectively realize being connected of foam metal and mass flow pole simultaneously, can adopt standardized subassembly to accomplish completely, very big reduction the error that manual fixation brought. The trifurcate gasket and the porous metal plate can effectively improve the current collection effect while not influencing the condition that the negative electrode metal or alloy enters the foam metal in the reaction process; the three-prong pad structure design can realize the axial control of the foam metal, simultaneously, the surface area of the foam metal is minimized, and the influence of the foam metal on the adsorption metal or alloy is reduced to the maximum extent.

By adopting the structural design and the assembly method of the negative current collector, the liquid metal battery capable of stably charging and discharging is prepared. As shown in fig. 7, the upper layer curve is a voltage-time curve, and the lower layer curve is a current-time curve. The consistency of the results of multiple tests is high. Specific properties are shown in table 1.

TABLE 1

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. The utility model provides a liquid metal battery negative pole mass flow body structure which characterized in that: comprises a fluid collecting rod (1), a porous metal plate (2), a foam metal (3) and a trident gasket (5); the current collector rod (1) is connected with the porous metal plate (2), the foam metal (3) is clamped between the porous metal plate (2) and the three-fork gasket (5) and attached to the porous metal plate, and the three-fork gasket (5) is connected with the current collector rod (1) through a conductor fastener;

the three-prong gasket (5) consists of a circular ring and three prongs (8) arranged in the circular ring, the central connection part of the three prongs (8) is bent upwards to form a protrusion (7) with a rib, the center of the protrusion (7) is provided with a central hole, and the lower end of the bent part forms a groove for mounting a conductor fastener;

the foam metal is axially and horizontally positioned through the conductor fastener and the current collector rod, and the rotation of the foam metal in the horizontal direction is limited by the protrusions on the three-fork gasket; the parallelism of the foam metal is controlled by parallel extrusion of the porous metal plate and the trident gasket, so that the stress deformation of the foam metal is reduced.

2. The liquid metal battery negative current collector structure of claim 1, wherein: the bottom of the current collector rod (1) is provided with an inner screw hole, and the conductor fastener is a screw (4); the end part of the screw (4) sequentially penetrates through the three-fork gasket (5) and the foam metal (3) and is in threaded connection with the current collector rod (1).

3. The liquid metal battery negative current collector structure of claim 1, wherein: the porous metal plate (2) is provided with a plurality of holes, and the central hole of the porous metal plate (2) is used for installing the current collector rod (1).

4. The liquid metal battery negative current collector structure of claim 1, wherein: the metal foam (3) is provided with a central through hole for penetrating through a conductor fastener, a recess (6) for mounting and limiting rotation of the three-fork gasket (5) is formed in the center of the bottom surface of the metal foam (3), and the shape of the recess (6) is matched with that of the protrusion (7).

5. The liquid metal battery negative current collector structure of claim 1, wherein: the current collector rod (1), the porous metal plate (2), the foam metal (3), the conductor fastener and the three-fork gasket (5) are coaxially arranged.

6. The liquid metal battery negative current collector structure of claim 1, wherein: the current collecting rod (1), the porous metal plate (2), the screw (4) and the three-fork gasket (5) are made of stainless steel, oxygen-free copper or titanium alloy materials; the foam metal (3) adopts Al, Cu, Ni, NiCrFe, ZnCu, NiCu, NiCrW or NiFe.

7. The liquid metal battery negative current collector structure of claim 1, wherein: when the current collector rod (1) is made of oxygen-free copper or titanium alloy, a corrosion-resistant material is adopted to coat the current collector rod (1) and form tight fit, and the corrosion-resistant material is welded with the porous metal plate (2); when the collector bar (1) is made of stainless steel, the collector bar (1) is directly welded with the porous metal plate (2).

8. A method of assembling a liquid metal battery negative current collector structure as claimed in any of claims 1 to 7, comprising the steps of:

1) nesting the current collector rod (1) and an inner hole of the porous metal plate (2), and welding and fixing;

2) attaching the upper surface of the foam metal (3) to the lower surface of the welded porous metal plate (2), attaching the three-fork gasket (5) to the lower surface of the foam metal (3), and fastening the four by sequentially penetrating the three-fork gasket (5) and the foam metal (3) through a conductor fastener and connecting the conductor fastener with the current collector rod (1).