Sealing and insulating electrode of liquid metal battery

Abstract

The utility model relates to the technical field of liquid metal electrodes, in particular to a liquid metal battery sealing insulation electrode which comprises an electrode core and a battery cover plate, the electrode core is sleeved with an upper transition ring, a ceramic-glass sealing structure and a lower transition ring from top to bottom, a through hole is formed in the battery cover plate, and the lower transition ring is connected with the inner wall of the through hole in a sealing mode. A fit clearance between the ceramic-glass sealing structure and the electrode core is filled with a first glass sealing layer, a fit clearance between the ceramic-glass sealing structure and the upper transition ring is filled with a second glass sealing layer, and a fit clearance between the ceramic-glass sealing structure and the lower transition ring is filled with a third glass sealing layer. The utility model has the beneficial effects that the assembly gaps between the upper transition ring, the lower transition ring, the electrode core and the ceramic-glass sealing mechanism are filled with glass powder softened during sintering to form a glass sealing layer, so that the sealing area is increased, the sealing stability can be ensured, and the service life of the electrode is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of liquid metal electrodes, in particular to a sealed insulating electrode for a liquid metal battery. Background Art

[0002] Liquid metal batteries are high-temperature batteries, typically operating at temperatures between 300°C and 700°C. Their positive and negative electrodes are liquid metal, and their electrolyte is a liquid inorganic molten salt. During operation, the positive, electrolyte, and negative electrode materials have different densities and are mutually insoluble, forming layers from bottom to top. During discharge, the negative electrode metal loses electrons to form ions, which then pass through the electrolyte and react with the positive electrode metal to form an alloy phase. Conversely, during charging, the alloy phase is re-electrolyzed into the positive electrode material and negative electrode metal ions. The negative electrode metal ions then pass through the electrolyte to form negative electrode metal on the negative electrode side.

[0003] Liquid metal batteries typically use a stainless steel casing as the positive electrode current collector. The negative electrode current collector is drawn from the battery cavity and tightly connected to the positive electrode casing in a certain manner, forming a closed battery structure. This battery has a simple structure and is easy to assemble. It also offers the advantages of low cost and long life, making it an ideal choice for large-scale grid energy storage applications.

[0004] During the operation of liquid metal batteries, the chemical properties of the electrodes and electrolyte materials are very active. Once they come into contact with water, oxygen, nitrogen, etc. in the air, they will quickly deteriorate and cause the battery to fail. At the same time, at room temperature, the electrodes and electrolyte materials still show a certain degree of activity. When they come into contact with water, oxygen, nitrogen, etc. in the air, they will gradually deteriorate and cause the battery to fail. Therefore, it is crucial to design a stable and reliable insulating and sealing structure for liquid metal batteries. However, due to the particularity of the operating environment of liquid metal batteries, conventional high-temperature insulating and sealing methods cannot effectively solve the problem. On the one hand, the current welding of the ceramic insulating sleeve and the transition ring on the electrode core is only brazed at the outer welding point, and the sealing position accounts for a limited proportion; on the other hand, it is difficult for high-temperature resistant inorganic glue to simultaneously meet the use requirements of liquid metal batteries in terms of thermal expansion coefficient, mechanical bonding strength, high-temperature insulation, chemical stability, etc.

[0005] Existing stable sealing technologies mainly focus on leading the sealing part of the liquid metal battery out of the high-temperature environment for room-temperature sealing. The problem with this type of sealing is that, on the one hand, it is easy to cause the sealing structure to be too large, the space utilization rate is extremely poor, and the sealing cost is also very high. On the other hand, for the battery cells to be packaged into groups, the entire battery cell needs to be packaged in a cabinet, and the environment in which the electrode rod is located is consistent with the operating temperature of the battery body (300℃~700℃). At this time, the silver-copper solder used in the brazing position of the insulating sleeve and the valve alloy is very easy to oxidize at high temperatures. At the same time, it is also affected by the metal vapor and salt vapor inside the battery, and then it is very easy to develop into sealing failure. This requires extremely strict requirements on the high-temperature sealing and durability of the electrode rod.

[0006] The Chinese invention patent application number 201710244870.7 discloses a sealed insulated electrode for liquid metal batteries and a preparation method thereof. By improving the solder, increasing the welding area and other methods, the reliability of welding is improved, thereby ensuring the sealing of the battery. However, this method has a limited welding area and a single sealing method, and there is a problem that the service life of the electrode is short at the working temperature; the Chinese invention patent application number 201710245823.4 discloses a high-temperature sealed electrode and a preparation method thereof. The sealing of the electrode is achieved by heating and curing the sealing salt, and the structure is relatively complex. Utility Model Content

[0007] The purpose of the utility model is to improve the sealing and insulating effect of a liquid metal battery. In view of the above-mentioned deficiencies in the prior art, a sealed and insulating electrode for a liquid metal battery is proposed.

[0008] A sealed insulated electrode for a liquid metal battery comprises an electrode core and a battery cover, wherein an upper transition ring, a ceramic-glass sealing structure and a lower transition ring are sleeved on the electrode core from top to bottom, a through hole is provided on the battery cover, and the lower transition ring is sealed to the inner wall of the through hole, a first glass sealing layer is filled in the fitting gap between the ceramic-glass sealing structure and the electrode core, a second glass sealing layer is filled in the fitting gap between the ceramic-glass sealing structure and the upper transition ring, and a third glass sealing layer is filled in the fitting gap between the ceramic-glass sealing structure and the lower transition ring.

[0009] By adopting the above technical solution: a ceramic-glass multilayer structure is sleeved on the electrode core of the utility model, the ceramic-glass multilayer structure is sealed to the electrode core through a first glass sealing layer, sealed to the upper transition ring through a second glass sealing layer, and sealed to the lower transition ring through a third glass sealing layer. The ceramic-glass multilayer structure is used to seal the battery, and the entire sealing process is sintered, with a good sealing effect, which can block the overflow of metal vapor and salt vapor.

[0010] The above technical solution is further configured as follows: the ceramic-glass sealing structure includes a ceramic ring and two glass rings, and the two glass rings are respectively located at the upper and lower ends of the ceramic ring.

[0011] The above technical solution is further configured as follows: the upper transition ring consists of a first annular portion and a first columnar portion, the upper end of the first columnar portion is fixedly connected to the outer ring of the first annular portion, and the lower end of the first columnar portion is welded to the outer wall of the ceramic ring.

[0012] The above technical solution is further configured as follows: the upper surface of the first annular portion is welded to the electrode core, and the lower surface of the first annular portion is bonded to the glass ring.

[0013] The above technical solution is further configured as follows: the lower transition ring consists of a second annular portion and a second columnar portion, the lower end of the second columnar portion is fixedly connected to the outer ring of the second annular portion, and the upper end of the second columnar portion is welded to the outer wall of the ceramic ring.

[0014] The above technical solution is further configured as follows: the lower surface of the second annular portion is welded to the electrode core, and the upper surface of the second annular portion is bonded to the glass ring.

[0015] By adopting the above technical solution: before preparing the ceramic-glass sealing structure, a lower transition ring, a ceramic-glass sealing structure blank and an upper transition ring are sleeved on the electrode core from bottom to top. The ceramic-glass sealing structure blank is composed of a pre-sintered ceramic ring and two glass material rings pressed from glass powder. The two glass material rings are located at the upper and lower ends of the ceramic ring and are in contact with the upper transition ring and the lower transition ring respectively.

[0016] A pressing tool is used to press the upper transition ring and the lower transition ring toward the middle, and the upper transition ring, the lower transition ring and the ceramic-glass sealing structure blank are placed in a sintering furnace for sintering. During sintering, the softened glass powder flows and fills the fitting gap between the ceramic-glass sealing structure and the electrode core, and forms a first glass sealing layer after cooling. During sintering, the softened glass powder flows and fills the fitting gap between the ceramic-glass sealing structure and the upper transition ring and the lower transition ring, and forms a second glass sealing layer and a third glass sealing layer after cooling, thereby obtaining a ceramic-glass sealing structure.

[0017] The above technical solution is further configured as follows: the lower end of the second columnar portion is welded to the through hole of the battery cover.

[0018] After sintering is completed, the upper transition ring, the lower transition ring, the electrode core and the ceramic ring are welded to strengthen the connection between the upper transition ring, the lower transition ring and the electrode core.

[0019] The above technical solution is further configured as follows: the electrode core is made of one of stainless steel, oxygen-free copper, titanium alloy or sealing alloy.

[0020] The above technical solution is further configured as follows: the surface of the electrode core is coated with a coating layer, and the coating layer is made of glass sealing alloy.

[0021] The above technical solution is further configured as follows: the material of the upper transition ring and the lower transition ring is Kovar alloy.

[0022] By adopting the above technical solution: the glass sealing alloy preferably uses 4J49 alloy, the glass sealing alloy and the glass powder have similar expansion coefficients, the glass powder has good wettability after softening, and a good sealing surface can be formed.

[0023] The beneficial effects of the utility model are:

[0024] 1. The sealing part of the utility model is composed of a ceramic-glass sealing structure, which has a good sealing effect and can block the overflow of metal vapor and salt vapor; at the same time, the assembly gap between the upper transition ring, the lower transition ring and the electrode core and the ceramic-glass sealing mechanism is filled with glass powder softened during sintering to form a first glass sealing layer, a second glass sealing layer and a third glass sealing layer, which increases the sealing area, effectively resists the erosion of internal metal vapor, ensures the stability of the seal, and improves the service life of the electrode.

[0025] 2. The glass rings of the ceramic-glass sealing structure are located at the upper and lower ends of the ceramic ring. The upper and lower glass rings are in contact with the upper transition ring and the lower transition ring respectively. During the sintering process, a good sealing surface is formed between the glass ring and the upper transition ring and the lower transition ring. The ceramic ring plays the role of a skeleton connecting the upper transition ring and the lower transition ring, ensuring the stability of the structure during sintering and preventing the softened glass powder from overflowing.

[0026] 3. Compared with the single brazing electrode sealing structure, the present invention has more sealing surfaces between the electrode core and the ceramic-glass sealing structure, and has a higher bonding strength.

[0027] 4. The ceramic-glass sealing structure of the present invention can still maintain a certain sealing effect even when the solder fails due to oxidation, isolating the external gas environment and further extending the service life of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the structure of the utility model.

[0029] In the figure, 1. electrode core; 2. battery cover; 3. lower transition ring; 31. second annular portion; 32. second columnar portion; 4. ceramic-glass sealing structure; 41. ceramic ring; 42. glass ring; 5. upper transition ring; 51. first annular portion; 52. first columnar portion; 6. through hole; 7. first glass sealing layer; 8. second glass sealing layer; 9. third glass sealing layer. DETAILED DESCRIPTION

[0030] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0031] Example 1

[0032] A liquid metal battery sealed insulated electrode, such as Figure 1 As shown, it includes an electrode core 1 and a battery cover plate 2. The electrode core 1 is provided with a lower transition ring 3, a ceramic-glass sealing structure 4 and an upper transition ring 5 from bottom to top. The battery cover plate 2 is provided with a through hole 6, and the lower end of the lower transition ring 3 is welded to the through hole 6.

[0033] The fitting gap between the ceramic-glass sealing structure 4 and the electrode core 1 is filled with a first glass sealing layer 7, the fitting gap between the ceramic-glass sealing structure 4 and the upper transition ring 5 is filled with a second glass sealing layer 8, and the fitting gap between the ceramic-glass sealing structure 4 and the lower transition ring 3 is filled with a third glass sealing layer 9.

[0034] The ceramic-glass sealing structure 4 consists of a ceramic ring 41 and glass rings 42 located at the upper and lower ends of the ceramic ring 41 respectively. Before preparing the ceramic-glass sealing structure 4, the lower transition ring 3, the ceramic-glass sealing structure 4 blank and the upper transition ring 5 are sleeved on the electrode core 1 from bottom to top. The ceramic-glass sealing structure 4 blank consists of a pre-sintered ceramic ring 41 and two glass material rings pressed from glass powder. The two glass material rings are located at the upper and lower ends of the ceramic ring 41 and are in contact with the upper transition ring 5 and the lower transition ring 3 respectively.

[0035] A pressing tool is used to press the upper transition ring 5 and the lower transition ring 3 toward the middle, and the upper transition ring 5, the lower transition ring 3 and the ceramic-glass sealing structure 4 blank are placed in a sintering furnace for sintering. During sintering, the softened glass powder flows and fills the fitting gap between the ceramic-glass sealing structure 4 and the electrode core 1, and forms a first glass sealing layer 7 after cooling. During sintering, the softened glass powder flows and fills the fitting gap between the ceramic-glass sealing structure 4 and the upper transition ring 5 and the lower transition ring 3, and forms a second glass sealing layer 8 and a third glass sealing layer 9 respectively after cooling, thereby obtaining a ceramic-glass sealing structure 4.

[0036] The electrode core 1 is made of stainless steel, and the surface of the electrode core 1 is covered with a glass sealing alloy. The glass sealing alloy has a similar expansion coefficient to the glass powder. After the glass powder softens, it has good wettability to the glass powder and can form a good sealing surface.

[0037] Example 2

[0038] The upper transition ring 5 and the lower transition ring 3 are made of Kovar alloy. The upper transition ring 5 consists of a first annular portion 51 and a first columnar portion 52. The upper end of the first columnar portion 52 is fixedly connected to the outer ring of the first annular portion 51, and the lower end of the first columnar portion 52 is welded to the outer wall of the ceramic ring 41. The upper surface of the first annular portion 51 is welded to the electrode core 1, and the lower surface of the first annular portion 51 is bonded to the glass ring 42 when the glass ring is sintered; the lower transition ring 3 consists of a second annular portion 31 and a second columnar portion 32. The lower end of the second columnar portion 32 is fixedly connected to the outer ring of the second annular portion 31, the upper end of the first columnar portion 52 is welded to the outer wall of the ceramic ring 41, the lower surface of the first annular portion 51 is welded to the electrode core 1, and the lower surface of the first annular portion 51 is bonded to the glass ring 42.

[0039] Any matters not mentioned above shall be subject to the existing technology.

[0040] Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art of the present invention may make various modifications or additions to the described specific embodiments or replace them with similar methods, but they will not deviate from the direction of the present invention or exceed the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent replacements, improvements, etc. made to the above embodiments based on the technical essence of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sealed insulated electrode for a liquid metal battery, characterized in that: The invention comprises an electrode core (1) and a battery cover (2), wherein the electrode core (1) is sleeved with an upper transition ring (5), a ceramic-glass sealing structure (4) and a lower transition ring (3) from top to bottom, the battery cover (2) is provided with a through hole (6), the lower transition ring (3) is sealed to the inner wall of the through hole (6), the fitting gap between the ceramic-glass sealing structure (4) and the electrode core (1) is filled with a first glass sealing layer (7), the fitting gap between the ceramic-glass sealing structure (4) and the upper transition ring (5) is filled with a second glass sealing layer (8), and the fitting gap between the ceramic-glass sealing structure (4) and the lower transition ring (3) is filled with a third glass sealing layer (9).

2. The sealed insulated electrode for liquid metal batteries according to claim 1, characterized in that: The ceramic-glass sealing structure (4) comprises a ceramic ring (41) and two glass rings (42), wherein the two glass rings (42) are respectively located at the upper and lower ends of the ceramic ring (41).

3. The sealed insulated electrode for liquid metal battery according to claim 2, characterized in that: The upper transition ring (5) consists of a first annular portion (51) and a first columnar portion (52), the upper end of the first columnar portion (52) is fixedly connected to the outer ring of the first annular portion (51), and the lower end of the first columnar portion (52) is welded to the outer wall of the ceramic ring (41).

4. The sealed insulated electrode for liquid metal batteries according to claim 3, characterized in that: The upper surface of the first annular portion (51) is welded to the electrode core (1), and the lower surface of the first annular portion (51) is bonded to the glass ring (42).

5. The sealed insulated electrode for liquid metal battery according to claim 2, characterized in that: The lower transition ring (3) consists of a second annular portion (31) and a second columnar portion (32), the lower end of the second columnar portion (32) is fixedly connected to the outer ring of the second annular portion (31), and the upper end of the second columnar portion (32) is welded to the outer wall of the ceramic ring (41).

6. The sealed insulated electrode for liquid metal batteries according to claim 5, characterized in that: The lower surface of the second annular portion (31) is welded to the electrode core (1), and the upper surface of the second annular portion (31) is bonded to the glass ring (42).

7. The sealed insulated electrode for liquid metal battery according to claim 5, characterized in that: The lower end of the second columnar portion (32) is welded to the through hole (6) of the battery cover plate (2).

8. The sealed insulated electrode for liquid metal batteries according to claim 1, characterized in that: The electrode core (1) is made of one of stainless steel, oxygen-free copper, titanium alloy or sealing alloy.

9. The sealed insulated electrode for liquid metal battery according to claim 1, characterized in that: The surface of the electrode core (1) is covered with a coating layer, and the coating layer is made of glass sealing alloy.

10. The sealed insulated electrode for liquid metal battery according to claim 1, characterized in that: The upper transition ring (5) and the lower transition ring (3) are made of Kovar alloy.

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