Highly sealed sodium battery
By employing a multi-stage gas-liquid separation structure and a stepped vent design, the problem of gas escape during electrode liquid expansion in sodium batteries is solved, achieving efficient electrolyte separation and dynamic control of battery sealing, thus ensuring battery safety and sealing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- FU NENG GRP CO LTD
- Filing Date
- 2025-07-02
- Publication Date
- 2026-07-24
AI Technical Summary
Existing high-sealing sodium batteries are prone to gas escape when the electrode liquid expands, leading to electrolyte loss and safety hazards. Furthermore, the venting efficiency cannot be dynamically adjusted, which can easily cause problems such as delayed or excessive pressure release.
Employing a multi-stage gas-liquid separation structure and a stepped exhaust port design, the gas-liquid mixture is separated through an interlaced separation network and a nanoscale gas-liquid separation membrane. Combined with the synergistic effect of the piston and spring, dynamic exhaust control with adaptive gas pressure is achieved. The electrolyte is returned using a duckbill valve to ensure battery sealing and safety.
It effectively avoids electrolyte loss, eliminates safety hazards, achieves dynamic matching of gas pressure and exhaust rate, and ensures the integrity and safety of the battery sealing structure.
Smart Images
Figure CN224554604U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of sodium battery technology, and in particular to a highly sealed sodium battery. Background Technology
[0002] Sodium-ion batteries, also known as sodium batteries, are a type of rechargeable battery that works primarily by the movement of sodium ions between the positive and negative electrodes, similar to the working principle of lithium-ion batteries. The electrode materials used in sodium-ion batteries are mainly sodium salts, which are more abundant and cheaper than lithium salts. Because sodium ions are larger than lithium ions, sodium-ion batteries are a cost-effective alternative when weight and energy density are not critical requirements.
[0003] Previously, a publicly disclosed technology proposed a highly sealed sodium battery. When the electrode fluid inside the inner cylinder undergoes thermal expansion and contraction, the lower end of the inner cylinder can compress or stretch a spring, which effectively buffers the lower end of the inner cylinder. Deformation at the upper end of the inner cylinder can be buffered by a buffer ring, further preventing severe deformation of the inner cylinder that could affect the battery's sealing performance. However, because the electrode fluid is located inside the inner cylinder, gas generated during expansion directly acts on the inner cylinder, causing deformation or even cracking, thus failing to achieve a true seal. In view of this, an improved technology proposes a highly sealed sodium battery, including a casing, with a positive and negative electrode rod inside. An outer cover plate is located on the top of the casing, and a cylindrical protrusion is fixedly connected to the top surface of the outer cover plate. Vent holes are formed on the axial surface of the cylindrical protrusion. The improved technology states that if the electrolyte is accidentally oxidized and produces gas, the gas will compress the piston and cause it to move upward. The piston will then drive the spring to compress. When the piston is at the top of the exhaust pipe, the gas will be discharged from the exhaust port. This avoids the gas causing the outer casing to expand and deform, and prevents the outer casing from expanding and damaging the battery's seal.
[0004] However, the above-mentioned improved technology still has some significant drawbacks. First, the gas-liquid mixed electrolyte is prone to escape from a single vent during the venting process, resulting in electrolyte loss and creating safety hazards. Second, a single vent with a fixed diameter cannot dynamically adjust the venting efficiency according to the internal pressure gradient, which can easily lead to pressure relief delay or excessive pressure relief under high pressure conditions. Utility Model Content
[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a highly sealed sodium battery.
[0006] To achieve the above objectives, this utility model adopts the following technical solution: a high-sealing sodium battery, comprising a sodium battery body and a cover plate assembly disposed above the sodium battery body. The sodium battery body contains electrode posts and electrolyte. The cover plate assembly includes an outer cover plate and an inner cover plate disposed below the outer cover plate. A sealing plate is fixedly connected between the outer cover plate and the inner cover plate. An exhaust pipe is fixedly connected to the inner sidewall of the inner cover plate. The upper end of the exhaust pipe penetrates the sealing plate and the outer cover plate and extends above the outer cover plate. Three sets of exhaust holes are provided on the circumferential outer wall of the portion of the exhaust pipe above the outer cover plate. The holes are distributed in a stepped manner along the axial direction of the exhaust pipe. A stop block is fixedly connected to the inner sidewall of the exhaust pipe near the lower end. A piston is slidably connected to the inner sidewall of the exhaust pipe above the stop block. A spring is provided between the upper end of the piston and the upper inner sidewall of the exhaust pipe. A liquid collection box is fixedly connected to one end of the exhaust pipe inside the sodium battery body. An air inlet is provided on the sidewall of the liquid collection box. A liquid collection chamber is formed inside the liquid collection box. A return pipe is fixedly connected to the lower wall of the liquid collection box. A duckbill valve is fixedly connected to the end of the return pipe that is connected to the liquid collection chamber and away from the liquid collection box. A first separation structure and a second separation structure are arranged sequentially from bottom to top on the inner sidewall of the liquid collection chamber.
[0007] As a further description of the above technical solution:
[0008] The first separation structure includes a first separation net, a second separation net, and a third separation net. The first separation net, the second separation net, and the third separation net are all fixedly connected to the inner wall of the liquid collection chamber and are all located above the air inlet. The first separation net, the second separation net, and the third separation net are all stainless steel meshes with a 45° staggered mesh size and a mesh diameter of 0.5mm.
[0009] As a further description of the above technical solution:
[0010] The second separation structure includes an open back plate and a gas-liquid separation membrane. The open back plate is fixedly connected to the inner wall of the liquid collection chamber and located above the first separation structure. The gas-liquid separation membrane is fixedly connected to the lower wall of the open back plate. The gas-liquid separation membrane is a nanoporous PTFE membrane with a pore size of 0.22 μm. The open porosity of the open back plate is greater than 45%. The gas-liquid separation membrane and the open back plate are joined by hot-pressing composite connection. The gas-liquid separation membrane completely covers the open area of the open back plate.
[0011] As a further description of the above technical solution:
[0012] The first, second, and third separation nets are all arched with their centers pointing upwards.
[0013] As a further description of the above technical solution:
[0014] The inner wall of the stop block is provided with a conical hole with a larger opening at the top and a smaller opening at the bottom. The lower end of the piston is provided with a conical seal that matches the conical hole. The outer wall of the piston is provided with an annular seal for sliding seal with the inner wall of the exhaust pipe.
[0015] As a further description of the above technical solution:
[0016] The liquid collection box is a stamped part made of 316L stainless steel, and the inner wall of the liquid collection box is electropolished to Ra≤0.8μm.
[0017] As a further description of the above technical solution:
[0018] A guide cone surface with a cone angle of 30°-45° is provided at the connection between the return pipe and the lower wall of the collection box.
[0019] As a further description of the above technical solution:
[0020] The duckbill valve and the return pipe are tightly connected by clamps.
[0021] This utility model has the following beneficial effects:
[0022] 1. Compared with existing technologies, this high-sealing sodium battery effectively avoids the problem of electrolyte leakage with gas through a multi-stage gas-liquid separation structure: During the process of electrolyte oxidation and gas generation, the gas-liquid mixture flows through a multi-layered interlaced separation network and a nano-scale gas-liquid separation membrane to achieve efficient separation of gas and liquid electrolyte. The separated electrolyte is reintroduced into the battery cavity through a one-way reflux valve, which not only prevents performance degradation caused by electrolyte loss, but also eliminates the safety hazards caused by direct discharge of gas-liquid mixture through traditional vent holes.
[0023] 2. Compared with existing technologies, this high-sealing sodium battery achieves dynamic venting control with adaptive air pressure through the synergistic effect of stepped venting holes and springs: based on the changes in internal air pressure of the battery, the displacement of the piston under the action of the spring automatically adjusts the opening and closing state of the venting holes at different heights. In the low-pressure stage, only the bottom venting hole is opened to maintain micro-pressure relief, while in the high-pressure stage, the middle and upper venting holes are activated step by step to accelerate pressure relief, ensuring that the pressure relief rate and the gas production pressure are dynamically matched, avoiding the over-leakage or lag problems in the single-hole venting mode, and fundamentally maintaining the integrity of the battery's sealing structure. Attached Figure Description
[0024] Figure 1 This is a schematic diagram of the overall connection structure of the outer cover plate, inner cover plate, sealing plate, and exhaust pipe of a high-sealing sodium battery proposed in this utility model.
[0025] Figure 2 A partial cross-sectional view of the outer cover plate, inner cover plate, sealing plate, exhaust pipe, liquid collection box, and return pipe connection structure of a high-sealing sodium battery proposed in this utility model.
[0026] Figure 3 This invention proposes a high-sealing sodium battery. Figure 2 A magnified view of a section at point A in the middle;
[0027] Figure 4 This is a cross-sectional view of the internal structure of the baffle of a high-sealing sodium battery proposed in this utility model;
[0028] Figure 5 This is a schematic diagram of the connection structure of the piston, conical seal, and annular seal of a high-sealing sodium battery proposed in this utility model.
[0029] Legend:
[0030] 1. Outer cover plate; 2. Inner cover plate; 3. Sealing plate; 4. Exhaust pipe; 5. Exhaust port; 6. Liquid collection box; 7. Air inlet; 8. Liquid collection chamber; 9. Return pipe; 10. Duckbill valve; 11. Stop block; 1101. Conical hole; 12. Piston; 1201. Conical seal; 1202. Annular seal; 13. Spring; 14. First separation screen; 15. Second separation screen; 16. Third separation screen; 17. Gas-liquid separation membrane; 18. Perforated back plate. Detailed Implementation
[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0032] Reference Figures 1 to 5 The present invention provides a high-sealing sodium battery: including a sodium battery body and a cover plate assembly disposed above the sodium battery body. The sodium battery body is provided with an electrode post and an electrolyte. The cover plate assembly includes an outer cover plate 1 and an inner cover plate 2 disposed below the outer cover plate 1. A sealing plate 3 is fixedly connected between the outer cover plate 1 and the inner cover plate 2. An exhaust pipe 4 is fixedly connected to the inner side wall of the inner cover plate 2. The upper end of the exhaust pipe 4 passes through the sealing plate 3 and the outer cover plate 1 and extends to the top of the outer cover plate 1.
[0033] In order to achieve a dynamic balance between sealing and pressure relief when the electrolyte gas generation pressure fluctuates, a stop block 11 is fixedly connected to the inner wall of the exhaust pipe 4 near the lower end. A piston 12 is slidably connected to the inner wall of the exhaust pipe 4 above the stop block 11. A spring 13 is provided between the upper end of the piston 12 and the upper inner wall of the exhaust pipe 4. A conical hole 1101 with a larger upper opening and a smaller lower opening is provided on the inner wall of the stop block 11. A conical sealing element 1201 adapted to the conical hole 1101 is provided at the lower end of the piston 12. An annular sealing element 1202 for sliding sealing with the inner wall of the exhaust pipe 4 is provided on the outer wall of the piston 12.
[0034] When the internal gas pressure of the sodium battery increases, the gas pushes the piston 12 to slide upward against the elastic force of the spring 13, and the conical seal 1201 disengages from the conical hole 1101 to form an exhaust channel; when the gas pressure decreases, the spring 13 resets and pushes the piston 12 to move downward, and the conical seal 1201 fits tightly with the conical hole 1101, achieving dynamic sealing through the self-locking effect of the conical surface, effectively improving the sealing effect.
[0035] In order to adjust the exhaust rate according to the pressure gradient, the exhaust pipe 4 is provided with three sets of exhaust holes 5 on the circumferential outer wall above the outer cover plate 1. The three sets of exhaust holes 5 are distributed in a stepped manner along the axial direction of the exhaust pipe 4.
[0036] When piston 12 is pushed by low-pressure gas to open only the bottom exhaust port 5, the micro-pressure relief mode can maintain basic sealing. When high-pressure gas pushes piston 12 to move up to the middle and upper exhaust port 5, the multi-port coordinated exhaust accelerates pressure relief, avoiding the problem of slow pressure relief under high pressure or excessive pressure relief under low pressure when a single exhaust port 5 is used.
[0037] In order to collect and circulate the mixture of electrolyte and gas, the exhaust pipe 4 is fixedly connected to the liquid collection box 6 at one end inside the sodium battery body. The side wall of the liquid collection box 6 is provided with an air inlet 7. The liquid collection box 6 forms a liquid collection cavity 8 inside. The liquid collection box 6 is a stamped part of 316L stainless steel. The inner wall of the liquid collection box 6 is electrolytically polished to Ra≤0.8μm.
[0038] The electropolished inner wall reduces the resistance to liquid adhesion. When the gas-liquid mixture enters the liquid collection chamber 8 through the air inlet 7, the smooth surface ensures that the liquid flows quickly downward along the inner wall of the liquid collection chamber 8, avoiding the secondary vaporization caused by electrolyte retention.
[0039] In order to perform multi-stage separation of gas-liquid mixture, a first separation structure and a second separation structure are arranged sequentially from bottom to top on the inner wall of the liquid collection chamber 8. The first separation structure includes a first separation mesh 14, a second separation mesh 15 and a third separation mesh 16. The first separation mesh 14, the second separation mesh 15 and the third separation mesh 16 are all fixedly connected to the inner wall of the liquid collection chamber 8 and are all located above the air inlet 7. The first separation mesh 14, the second separation mesh 15 and the third separation mesh 16 are all stainless steel meshes with a 45° staggered mesh and a mesh diameter of 0.5mm. The first separation mesh 14, the second separation mesh 15 and the third separation mesh 16 are all arched with the center arching upward.
[0040] When the gas-liquid mixture impacts the arched separation net, the liquid is blocked by the net surface and converges downward along the arched curve, while the gas flows upward through the interlaced mesh. The stepped interception effect of the first separation net 14, the second separation net 15 and the third separation net 16 separates more than 90% of the liquid electrolyte and guides it to the bottom of the liquid collection chamber 8.
[0041] To further separate the tiny liquid droplets in the gas, the second separation structure includes an open back plate 18 and a gas-liquid separation membrane 17. The open back plate 18 is fixedly connected to the inner wall of the liquid collection chamber 8 and located above the first separation structure. The gas-liquid separation membrane 17 is fixedly connected to the lower wall of the open back plate 18. The gas-liquid separation membrane 17 is a nanoporous PTFE membrane with a pore size of 0.22 μm. The open porosity of the open back plate 18 is greater than 45%. The gas-liquid separation membrane 17 and the open back plate 18 are connected by hot-pressing composite. The gas-liquid separation membrane 17 completely covers the open area of the open back plate 18.
[0042] When gas passes through the perforated back plate 18, the gas-liquid separation membrane 17 traps droplets with a particle size > 0.22 μm. The dry gas is discharged through the exhaust pipe 4, while the trapped droplets flow back to the liquid collection chamber 8 along the lower surface of the gas-liquid separation membrane 17 under the action of gravity, thus achieving efficient gas-liquid separation.
[0043] In order to safely guide the separated electrolyte back to the battery cavity, a return pipe 9 is fixedly connected to the lower wall of the collection box 6. The end of the return pipe 9 that is connected to the collection cavity 8 and away from the collection box 6 is fixedly connected to a duckbill valve 10. A guide cone surface is provided at the connection between the return pipe 9 and the lower wall of the collection box 6, with a cone angle of 30°-45°. The duckbill valve 10 and the return pipe 9 are tightly connected by a clamp.
[0044] When the liquid level in the collecting chamber 8 rises, the liquid is accelerated into the return pipe 9 through the guide cone surface. The duckbill valve 10 opens unidirectionally under the liquid column pressure and flows back to the sodium battery body. When the liquid level drops, the duckbill valve 10 closes automatically to prevent gas or electrolyte backflow and maintain the internal pressure balance of the battery.
[0045] Working principle: When the internal gas pressure of the sodium battery increases, the gas pushes the piston 12 to slide upward against the elastic force of the spring 13, and the conical seal 1201 disengages from the conical hole 1101 to form an exhaust channel; when the gas pressure decreases, the spring 13 returns to its original position and pushes the piston 12 downward, and the conical seal 1201 fits tightly with the conical hole 1101, achieving dynamic sealing through the self-locking effect of the conical surface, effectively improving the sealing effect; when the piston 12 is pushed by low-pressure gas to open only the bottom exhaust hole 5, the micro-pressure relief mode can maintain basic sealing; when high-pressure gas pushes the piston 12 to move upward step by step to the middle and upper exhaust hole 5 positions, multi-hole coordinated exhaust accelerates pressure relief, avoiding the problem of slow pressure relief under high pressure or excessive pressure relief under low pressure in a single exhaust hole 5; the electrolytically polished inner wall reduces liquid adhesion resistance, and when the gas-liquid mixture enters the liquid collection chamber 8 through the air inlet 7, the smooth surface ensures that the liquid flows quickly downward along the inner wall of the liquid collection chamber 8, avoiding Electrolyte retention causes secondary vaporization; when the gas-liquid mixture impacts the arched separation mesh, the liquid is blocked by the mesh surface and converges downwards along the arched curve, while the gas flows upwards through the interlaced mesh. The stepped interception effect of the first separation mesh 14, the second separation mesh 15, and the third separation mesh 16 separates more than 90% of the liquid electrolyte and guides it to the bottom of the collection chamber 8; when the gas passes through the perforated back plate 18, the gas-liquid separation membrane 17 intercepts droplets with a particle size >0.22μm, the dry gas is discharged through the exhaust pipe 4, and the intercepted droplets flow back to the collection chamber 8 along the lower surface of the gas-liquid separation membrane 17 under the action of gravity, achieving efficient gas-liquid separation; when the liquid level in the collection chamber 8 rises, the liquid is accelerated into the return pipe 9 through the guide cone surface, and the duckbill valve 10 opens unidirectionally under the liquid column pressure and flows back to the sodium battery body; when the liquid level drops, the duckbill valve 10 closes automatically to prevent gas or electrolyte backflow and maintain the internal pressure balance of the battery.
[0046] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A highly sealed sodium battery, comprising a sodium battery body and a cover plate assembly disposed above the sodium battery body, wherein electrode posts and electrolyte are disposed within the sodium battery body, characterized in that: The cover plate assembly includes an outer cover plate (1) and an inner cover plate (2) disposed below the outer cover plate (1). A sealing plate (3) is fixedly connected between the outer cover plate (1) and the inner cover plate (2). An exhaust pipe (4) is fixedly connected to the inner side wall of the inner cover plate (2). The upper end of the exhaust pipe (4) passes through the sealing plate (3) and the outer cover plate (1) and extends to the top of the outer cover plate (1). Three sets of exhaust holes (5) are provided on the circumferential outer wall of the exhaust pipe (4) above the outer cover plate (1). The three sets of exhaust holes (5) are distributed in a stepped manner along the axial direction of the exhaust pipe (4). A stop block (11) is fixedly connected to the inner side wall of the exhaust pipe (4) near the lower end. A piston (12) is slidably connected to the inner wall of the block (11) above the piston (12). A spring (13) is provided between the upper end of the piston (12) and the inner upper wall of the exhaust pipe (4). The end of the exhaust pipe (4) located inside the sodium battery body is fixedly connected to the liquid collection box (6). An air inlet (7) is provided on the side wall of the liquid collection box (6). A liquid collection chamber (8) is formed inside the liquid collection box (6). A return pipe (9) is fixedly connected to the lower wall of the liquid collection box (6). A duckbill valve (10) is fixedly connected to the end of the return pipe (9) that is connected to the liquid collection chamber (8) and away from the liquid collection box (6). A first separation structure and a second separation structure are arranged sequentially from bottom to top on the inner wall of the liquid collection chamber (8).
2. The high-sealing sodium battery according to claim 1, characterized in that: The first separation structure includes a first separation mesh (14), a second separation mesh (15), and a third separation mesh (16). The first separation mesh (14), the second separation mesh (15), and the third separation mesh (16) are all fixedly connected to the inner wall of the liquid collection chamber (8) and are all located above the air inlet (7). The first separation mesh (14), the second separation mesh (15), and the third separation mesh (16) are all stainless steel meshes with a 45° staggered mesh and a mesh diameter of 0.5 mm.
3. A high-sealing sodium battery according to claim 2, characterized in that: The second separation structure includes an open back plate (18) and a gas-liquid separation membrane (17). The open back plate (18) is fixedly connected to the inner wall of the liquid collection chamber (8) and located above the first separation structure. The gas-liquid separation membrane (17) is fixedly connected to the lower wall of the open back plate (18). The gas-liquid separation membrane (17) is a nanoporous PTFE membrane with a pore size of 0.22 μm. The open back plate (18) has an opening rate of more than 45%. The gas-liquid separation membrane (17) and the open back plate (18) are connected by hot pressing. The gas-liquid separation membrane (17) completely covers the open area of the open back plate (18).
4. A high-sealing sodium battery according to claim 3, characterized in that: The first separation net (14), the second separation net (15) and the third separation net (16) are all arched with the center arching upward.
5. A highly sealed sodium battery according to claim 4, characterized in that: The inner wall of the stop block (11) is provided with a conical hole (1101) with a larger upper opening and a smaller lower opening. The lower end of the piston (12) is provided with a conical seal (1201) that is adapted to the conical hole (1101). The outer wall of the piston (12) is provided with an annular seal (1202) for sliding seal with the inner wall of the exhaust pipe (4).
6. A high-sealing sodium battery according to claim 5, characterized in that: The liquid collection box (6) is a 316L stainless steel stamped part, and the inner wall of the liquid collection box (6) is electropolished to Ra≤0.8μm.
7. A high-sealing sodium battery according to claim 6, characterized in that: A guide cone surface with a cone angle of 30°-45° is provided at the connection between the return pipe (9) and the lower wall of the collection box (6).
8. A high-sealing sodium battery according to claim 7, characterized in that: The duckbill valve (10) and the return pipe (9) are tightly connected by a clamp.