A button cell

Abstract

This invention discloses a button battery, relating to the field of micro battery technology. It includes a shell with a bottom surface and sidewalls extending around the edge of the bottom surface. A cap is connected to the upper edge of the shell. The cap includes a connecting ring with a through hole in the center and an electrode sheet connected to the surface wall of the connecting ring by a sealing insulating adhesive, covering the through hole. The connecting ring is welded to the upper edge of the shell. An electrode assembly is disposed inside the shell. One side of the electrode assembly is electrically connected to the inner wall of the shell by a conductor, and the other side of the electrode assembly is electrically connected to the electrode sheet by a conductor. The electrode sheet has a circular structure and is coaxially arranged with the connecting ring. The diameter of the electrode sheet is larger than the diameter of the through hole and smaller than the outer diameter of the connecting ring. The softening temperature of the sealing insulating adhesive is greater than or equal to 90°C. This button battery has a simple and ingenious structural design, low manufacturing cost, and can improve the capacity and specific energy density of the button battery. It also has good sealing, explosion-proof, and corrosion-resistant properties, as well as long storage time and service life.

Description

[0001] This invention is a divisional application based on the application filed on February 21, 2022, with application number 202210156221.2 and invention title "A Surface Treatment Process for a Button Battery and its Cap". Technical Field

[0002] This invention relates to the field of micro battery technology, and more particularly to a button battery. Background Technology

[0003] With the development of electronic technology, microelectronics technology and modern smart wearable devices, the market is constantly increasing its requirements for the power supply of electronic devices, which are becoming smaller and have higher energy density. At the same time, devices are also required to be portable and have a better battery life experience. For example, wireless TWS Bluetooth earphones, hearing aids, electronic gastrointestinal endoscopes, 3D glasses, etc., require products to be miniaturized and lightweight, while also meeting the requirements for battery life. Therefore, higher requirements are placed on the size and quality of batteries.

[0004] Currently, small soft-pack polymer batteries and button batteries on the market occupy a certain volume due to their structure and casing, making it difficult to further improve their energy density. This is especially true in smaller, more precise devices, where the requirements for battery placement space and corrosion resistance are significantly increased. Traditional steel-cased button batteries produce hydrofluoric acid when there is a trace amount of moisture in the electrolyte (a trace amount of moisture is unavoidable). After charging, under voltage and hydrofluoric acid conditions, the positive electrode metal of the steel-cased button battery is highly susceptible to electrochemical corrosion. This severely affects battery performance, including capacity loss, increased internal resistance over time, and poor cycle performance. As electrochemical corrosion deepens, it can completely destroy the battery, directly hindering its promotion and use in precision equipment. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems of existing micro batteries by providing a button cell battery. This button cell battery has a simple and compact structure, low manufacturing cost, and can improve battery capacity and specific energy density. It also has good sealing, explosion-proof, and corrosion-resistant properties.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: A button battery includes a housing having a bottom surface and sidewalls extending around the edge of the bottom surface. A cap is connected to the upper edge of the housing. The cap includes a connecting ring having a through hole in the middle and an electrode sheet connected to the surface wall of the connecting ring by a sealing insulating adhesive and used to cover the through hole. The connecting ring is welded to the upper edge of the housing. An electrode assembly is provided inside the housing. One side of the electrode assembly is electrically connected to the inner wall of the housing through a conductor, and the other side of the electrode assembly is electrically connected to an electrode sheet through a conductor. The electrode plate has a circular structure and is coaxially arranged with the connecting ring. The diameter of the electrode plate is larger than the diameter of the through hole and smaller than the outer diameter of the connecting ring. The softening temperature of the sealing and insulating adhesive is greater than or equal to 90°C.

[0007] Preferably, a stepped groove is provided around the periphery of the connecting ring, and the groove is adapted to the upper edge of the housing.

[0008] Preferably, the connecting ring is laser welded or resistance welded to the upper edge of the housing.

[0009] Preferably, the electrode sheet is attached to the inner wall of the connecting ring.

[0010] Preferably, the electrode sheet is attached to the outer wall of the connecting ring.

[0011] Preferably, the inner wall of the connecting ring is provided with an insulating pad.

[0012] Preferably, the sealing and insulating adhesive is made of modified polyethylene or epoxy resin.

[0013] Preferably, the electrode assembly has a spiral or stacked structure; a positive electrode conductor and a negative electrode conductor are respectively connected to both sides of the electrode assembly, the positive electrode conductor is an aluminum foil with a thickness of 0.006-0.018 mm, the negative electrode conductor is a copper foil with a thickness of 0.006-0.016 mm, and the positive electrode conductor and the negative electrode conductor have a rectangular, strip or strip structure.

[0014] Preferably, the thickness of the shell is 0.1-0.25 mm.

[0015] Preferably, the housing contains an electrolyte.

[0016] Preferably, the electrode sheet and connecting ring undergo surface treatment before being assembled into a button cell, and the surface treatment includes the following steps: S1. Prepare a first treatment solution, wherein the first treatment solution uses water or deionized water as a solvent and further includes: hexavalent chromium compound 15-35 g / L, phosphide 25-45 g / L, and fluoride 5-15 g / L; The hexavalent chromium compound is chromium chloride and / or potassium dichromate; the phosphide is phosphoric acid and / or polyphosphoric acid; the fluoride is ammonium fluoride and / or acidic sodium fluoride. S2. Treat the electrode sheet and connecting ring with the first treatment solution. Heat the first treatment solution to 40-70°C and spray the heated first treatment solution onto the electrode sheet and connecting ring for 5-10 minutes or immerse the electrode sheet and connecting ring in the heated first treatment solution for 3-6 minutes. After treatment, rinse with tap water. S3. Prepare a second treatment solution, which uses water or deionized water as a solvent and further includes: 25-45 g / L of organic acid, 10-20 g / L of fluorine compound, and 5-15 g / L of inorganic acid. The organic acid is oxalic acid and / or acrylic acid, the fluorine compound is ammonium fluoride and / or acidic sodium fluoride, and the inorganic acid is phosphoric acid and / or hydrochloric acid. S4. The electrode sheet and connecting ring obtained in step S2 are treated again with the second treatment solution. The second treatment solution is heated to 40-70°C and sprayed onto the electrode sheet and connecting ring for 5-10 minutes or the electrode sheet and connecting ring are immersed in the heated second treatment solution for 3-6 minutes. After treatment, they are rinsed with tap water. S5. Dry the electrode sheet and connecting ring at 80-120℃ for later use.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: This button battery features a simple and ingenious design. By welding the cap directly to the upper edge of the casing, it achieves excellent sealing performance, improving the battery's capacity and specific energy density. The connecting ring is welded to the upper edge of the casing, and the electrode plates are insulated and sealed to the connecting ring. The electrode plates and the casing or connecting ring respectively form the two electrodes of the button battery, integrating the two electrode surfaces of a traditional button battery onto one side. This expands the space available for fixing the battery in electrical devices, further reducing the size of the devices. This button battery also boasts excellent explosion-proof performance. The electrode plates and connecting ring are connected by a sealing insulating adhesive. When the internal pressure of the casing increases or the casing expands and heats up, the sealing insulating adhesive softens and releases pressure, achieving explosion-proof properties and preventing serious accidents caused by the button battery expanding, exploding, or catching fire. Furthermore, the surface of the electrode plates is treated to provide good corrosion resistance, extending the battery's lifespan. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 This is a structural diagram of a button battery in an embodiment of the present invention; Figure 2 This is an exploded view of a button battery in an embodiment of the present invention; Figure 3 This is a structural diagram of a button battery according to another embodiment of the present invention; In the diagram: 1 is the shell, 2 is the connecting ring, 21 is the through hole, 22 is the groove, 3 is the electrode sheet, 4 is the sealing insulating glue, 5 is the electrode assembly, 51 is the positive conductor, 52 is the negative conductor, and 6 is the insulating pad. Detailed Implementation

[0020] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] In the description of this application, it should be understood that the terms "middle," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0022] Furthermore, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0023] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0024] Example: Reference Figure 1-3 This invention primarily addresses the problems of existing button batteries, such as low capacity or specific energy density, lack of explosion-proof function, poor corrosion resistance, and short service life, by providing a button battery, such as... Figure 1 As shown, the button battery includes a housing 1 having a bottom surface and side walls extending around the edge of the bottom surface. The housing 1 is made of stainless steel. In this embodiment, the housing 1 is a cylindrical structure with an open top and a single wall thickness of 0.1-0.25 mm. A cap is connected to the upper edge of the housing 1 to form a hollow cavity.

[0025] The cap includes a connecting ring 2 with a through hole 21 in the middle and an electrode sheet 3 connected to the surface wall of the connecting ring 2 by a sealing insulating adhesive 4 to cover the through hole 21. The connecting ring 2 is welded to the upper edge of the shell 1. In this embodiment, the outer ring of the connecting ring 2 and the upper end of the cap are integrated by laser welding or resistance welding. The electrode sheet 3 and the connecting ring 2 are sealed and insulated by the sealing insulating adhesive 4, which can improve the sealing performance inside the cavity, avoid the risk of leakage, ensure the battery storage performance and service life, and thus improve electrical safety. Traditional steel-cased button batteries are prone to explosion and injury or damage to electrical equipment when heated due to structural limitations. If the steel-cased battery of this structure is thrown into a fire or in an accident, the battery will heat up or short-circuit and generate heat. Since the cap and the shell are laser welded, the internal pressure required to burst is much greater than that of the heated sealing insulating adhesive 4. First, the sealing insulating adhesive 4 softens and loses its sealing function, thereby releasing pressure to achieve the purpose of explosion prevention. Therefore, when the battery is abused due to heat, the sealing insulating adhesive 4 can be softened and released to achieve the purpose of explosion prevention.

[0026] This button battery has good explosion-proof performance. The electrode plate 3 and the connecting ring 2 are connected by a sealing insulating glue 4. When the air pressure inside the shell 1 increases and the shell 1 expands and gets heated, the sealing insulating glue 4 softens and releases pressure to achieve the purpose of explosion-proof, avoiding serious accidents caused by the expansion and explosion or fire of the button battery. After the surface of the electrode plate 3 of this button battery is treated, it has good corrosion resistance and can improve the service life of the button battery.

[0027] Furthermore, electrode 3 serves as one electrode of the button cell, and housing 1 and / or connecting ring 2 serve as the other electrode. Electrode assembly 5 and electrolyte are disposed within housing 1. One side of electrode assembly 5 is electrically connected to the inner wall of housing 1 via a conductor, and the other side of electrode assembly 5 is electrically connected to electrode 3 via a conductor. In this embodiment, electrode 3 is the positive electrode, and housing 1 and / or connecting ring 2 is the negative electrode. One side of electrode assembly 5 is welded to the inner wall of electrode 3 via a positive conductor 51, and the other side of electrode assembly 5 is welded to the bottom wall of housing 1 via a negative conductor 52.

[0028] In one specific embodiment, such as Figure 1 , Figure 2As shown, electrode plate 3 has a circular structure. The diameter of electrode plate 3 is larger than the inner diameter of connecting ring 2 but smaller than the outer diameter of connecting ring 2. Electrode plate 3 is coaxially attached to the inner wall of connecting ring 2 by sealing insulating adhesive 4. Through hole 21 is a circular hole, and the diameter of through hole 21 is larger than 1 / 3 of the outer diameter of connecting ring 2. By setting through hole 21, it is convenient for electrical equipment to be electrically connected to electrode plate 3. Of course, through hole 21 can also be designed as a polygonal hole according to actual needs. The diameter of through hole 21 can also be less than or equal to 1 / 3 of the outer diameter of connecting ring 2, as long as it can meet the requirement that electrical equipment can be electrically connected to electrode plate 3 without causing battery short circuit. In this embodiment, the electrode sheet 3 serves as one electrode of the battery, and the connecting ring 2 serves as the other electrode. The two electrode surfaces of the battery can be integrated into one electrode surface. During use, it can be electrically connected to the device using wires or probes. This reduces the space required for fixing the battery in the device, further reducing the size of the device, or increasing the battery's storage capacity and extending the device's lifespan. Furthermore, integrating one electrode surface eliminates the need for battery clips, battery holders, wires, and other accessories, reducing the production and usage costs of the device, while also aligning with environmental protection principles.

[0029] In another specific embodiment, such as Figure 3 As shown, the electrode sheet 3 is coaxially bonded to the outer wall of the connecting ring 2 via sealing insulating adhesive 4; the electrode sheet 3 is the positive electrode, and the housing 1 and / or connecting ring 2 is the negative electrode. Since the diameter of the electrode sheet 3 is larger than the inner diameter of the connecting ring 2 but smaller than the outer diameter of the connecting ring 2, in this embodiment, the two electrode surfaces of the battery can also be integrated into one electrode surface; one side of the electrode assembly 5 is welded to the inner wall of the electrode sheet 3 through the through hole 21 via the positive electrode conductor 51, and the other side of the electrode assembly 5 is welded to the inner wall of the housing 1 via the negative electrode conductor 52. Of course, to avoid the positive electrode conductor 51 contacting the inner wall of the connecting ring 2 and causing a short circuit in the battery, in this embodiment, the inner wall of the connecting ring 2 is provided with a thin sheet-like insulating pad 6, which prevents the positive electrode conductor 51 from contacting the inner wall of the connecting ring 2.

[0030] Specifically, in order to improve the ease of assembly between the cap and the housing 1, in this embodiment, a stepped groove 22 is provided around the periphery of the connecting ring 2. The groove 22 is adapted to the upper edge of the housing 1, which can prevent the cap from shifting before welding with the housing 1, thus avoiding assembly errors, improving assembly accuracy, and improving the ease of welding.

[0031] Specifically, the sealing and insulating adhesive is made of modified polyethylene or epoxy resin. In this embodiment, the sealing and insulating adhesive 4 is made of modified polypropylene. The specific modification method is: chemical modification followed by copolymerization and then further physical blending. It has excellent performance, and its impact resistance and creep resistance meet the battery requirements. Through testing, the physical properties of the modified sealing and insulating adhesive 4 are as follows: yield strength above 28 MPa, tensile strength above 30 MPa, and very good toughness, with an elongation at break of 500%. The modified sealing and insulating adhesive 4 interacts with the treated electrode sheet 3 to form stable hydrogen bonds, resulting in excellent sealing performance. Traditional steel-cased button batteries are usually sealed by extrusion, that is, there is an insulating sealing layer between the inner and outer metal casings of the battery, which is sealed by extrusion through a mold. The effect is a semi-sealed state, which is not conducive to battery storage and battery life, and it also does not have an explosion-proof effect. Of course, the sealing and insulating adhesive 4 can also be made of epoxy resin metal-friendly adhesive, such as HS1021 epoxy adhesive, RS2211 hot melt adhesive, etc., and is not limited to the above adhesives.

[0032] Furthermore, the sealing insulating adhesive is set with a softening temperature greater than or equal to 90°C. When the battery temperature reaches 90°C during thermal abuse, it begins to release pressure to achieve the purpose of explosion prevention. Specifically, if the steel-cased battery of this structure is thrown into a fire or an accident causes the battery to heat up or short-circuit, the internal pressure required to burst due to the laser welding between the cap and the casing is much greater than that of the heated sealing insulating adhesive 4. First, the sealing insulating adhesive 4 softens and loses its sealing function, thereby releasing pressure to achieve the purpose of explosion prevention. Therefore, once the battery temperature reaches 90°C during thermal abuse, the pressure release through the softening of the sealing insulating adhesive 4 can achieve the purpose of explosion prevention.

[0033] Specifically, the electrode assembly 5 has a spiral or stacked structure; the positive conductor 51 is an aluminum foil with a thickness of 0.006-0.018 mm, and the negative conductor 52 is a copper foil with a thickness of 0.006-0.016 mm. The positive conductor 51 and the negative conductor 52 have rectangular, strip, or strip structures. In this embodiment, the electrode assembly 5 is manufactured into a battery cell in two ways: One way: The electrode assembly 5 consists of a long rectangular positive electrode sheet connected to at least one metal conductor and electrically connected to the housing 1 or the electrode sheet 3; a layer of insulating material; a long rectangular negative electrode sheet connected to at least one metal conductor and electrically connected to the electrode sheet 3 or the housing 1; and another layer of insulating material, for a total of four layers stacked together and wound to form a cylindrical electrode assembly 5. The other way: The manufactured positive and negative electrodes are punched into a "ping-pong paddle" shape, wherein the handle of the "ping-pong paddle" shaped positive and negative electrodes is uncoated with positive and negative electrode materials, consisting only of the current collector copper foil and aluminum foil of the positive and negative electrodes. The insulating material is punched into a circular piece of the required size. The electrode assembly 5 is assembled by stacking the separator, the "ping-pong paddle" shaped negative electrode, the separator, and the "ping-pong paddle" shaped positive electrode sequentially until the required thickness is achieved to form a cylinder. The negative and positive electrodes are aligned with the "ping-pong paddle" shaped handles, and the positive and negative electrode handles are at 180°. Then, the positive and negative electrodes are respectively welded to two metal conductors, and the two metal conductors are then electrically connected to the battery casing 1 and the electrode sheet 3 to form a battery. In this embodiment, the positive electrode conductor 51 (i.e., the positive electrode energizer) is a 0.006-0.018 mm thick aluminum foil coated with lithium cobalt oxide or other positive electrode materials to form the positive electrode, and the negative electrode conductor 52 (i.e., the negative electrode energizer) is a 0.006-0.016 mm thick copper foil coated with graphite to form the negative electrode.

[0034] Specifically, to improve the adhesion of the sealing and insulating adhesive 4 to the connecting ring 2 and the electrode sheet 3, and to improve the corrosion resistance of the electrode sheet 3, the present invention also provides a surface treatment process for the cap, used to treat the cap in the above embodiments. The process includes the following steps: S1. Prepare a first treatment solution, wherein the first treatment solution uses water or deionized water as a solvent and further includes: hexavalent chromium compound 15-35 g / L, phosphide 25-45 g / L, and fluoride 5-15 g / L; The hexavalent chromium compound is chromium chloride and / or potassium dichromate; the phosphide is phosphoric acid and / or polyphosphoric acid; the fluoride is ammonium fluoride and / or acidic sodium fluoride. In a preferred embodiment, water or deionized water is used as the solvent, and 25 g / L of chromium chloride, 35 g / L of phosphoric acid, and 10 g / L of ammonium fluoride are added to prepare the first treatment solution.

[0035] S2. Treat the electrode sheet 3 and the connecting ring 2 with the first treatment solution. Heat the first treatment solution to 40-70°C and spray the heated first treatment solution onto the electrode sheet 3 and the connecting ring 2 for 5-10 minutes or immerse the electrode sheet 3 and the connecting ring 2 in the heated first treatment solution for 3-6 minutes. After treatment, rinse with tap water. In this embodiment, electrode sheet 3 and connecting ring 2 are first stamped and formed. The preferred material is stainless steel or aluminum. Electrode sheet 3 and connecting ring 2 are treated with the first treatment solution prepared in step S1. Preferably, the first treatment solution is heated to 50°C and sprayed onto electrode sheet 3 and connecting ring 2 for 8 minutes or the electrode sheet 3 and connecting ring 2 are immersed in the heated first treatment solution for 4 minutes. After treatment, they are washed with tap water.

[0036] S3. Prepare a second treatment solution, which uses water or deionized water as a solvent and further includes: 25-45 g / L of organic acid, 10-20 g / L of fluorine compound, and 5-15 g / L of inorganic acid. The organic acid is oxalic acid and / or acrylic acid, the fluorine compound is ammonium fluoride and / or acidic sodium fluoride, and the inorganic acid is phosphoric acid and / or hydrochloric acid. In a preferred embodiment, water or deionized water is used as the solvent, and 35 g / L of oxalic acid, 15 g / L of ammonium fluoride, and 10 g / L of phosphoric acid are added to prepare the second treatment solution.

[0037] S4. The electrode sheet 3 and connecting ring 2 obtained in step S2 are treated again with the second treatment solution. The second treatment solution is heated to 40-70°C and sprayed onto the electrode sheet 3 and connecting ring 2 for 5-10 minutes or the electrode sheet 3 and connecting ring 2 are immersed in the heated second treatment solution for 3-6 minutes. After treatment, they are rinsed with tap water. In this embodiment, the electrode sheet 3 and the connecting ring 2, which have been processed in step S2, are then treated with a second treatment solution. Preferably, the second treatment solution is heated to 55°C and sprayed onto the electrode sheet 3 and the connecting ring 2 for 8 minutes, or the electrode sheet 3 and the connecting ring 2 are immersed in the heated first treatment solution for 4 minutes, and then rinsed with tap water.

[0038] S5. Dry the electrode sheet 3 and the connecting ring 2 at 80-120℃ for later use.

[0039] In this embodiment, the electrode sheet 3, which has been processed in step S4, is dried in an oven at a temperature of 100°C for later use.

[0040] After the electrode sheet 3 and the connecting ring 2 are processed through the above S1 to S5 steps, a dense chemical film layer is formed on the metal surface, which serves two purposes: 1. The electrode plate 3 and connecting ring 2 of this battery cap must be firmly bonded together using sealing insulating adhesive 4. The electrode plate 3 and connecting ring 2, manufactured using this method, form stable hydrogen bonds after being hot-pressed together with the sealing insulating adhesive 4 prepared in the above manner. That is, the sealing insulating adhesive 4 and the chemical layer on the metal surfaces of the electrode plate 3 and connecting ring 2 form stable intermolecular hydrogen bonds, achieving a strong bond. Testing has shown excellent electrolyte resistance; it can withstand immersion in an electrolyte solution containing 2000ppm water at 85℃ for 10 hours. This ensures the battery's storage performance and long-term sealing during subsequent use, improving the safety of the battery and the electrical equipment.

[0041] 2. The metal (stainless steel) surface layer of the electrode sheet 3 and connecting ring 2 treated in this way has a highly stable chemical film layer. Therefore, the battery made from this material can withstand higher voltages than traditional batteries, allowing for the use of higher voltage positive and negative electrode materials to further improve battery energy density. Traditional button lithium-ion batteries have a voltage of 4.2 volts. Tests have shown that batteries made using this method can withstand voltages of 4.5 volts or even higher without corrosion. This is because traditional steel-cased button batteries produce hydrofluoric acid when there is a trace amount of water in the electrolyte (a trace amount of water is unavoidable). After charging, under voltage and hydrofluoric acid conditions, the positive electrode metal of the steel-cased button battery is highly susceptible to electro-corrosion, meaning that the electrode sheet 3 in this embodiment is prone to electro-corrosion. This severely affects battery performance, including capacity loss, increased internal resistance over time, and poor cycle performance. As electro-corrosion deepens, it can eventually completely damage the battery. Therefore, the electrode sheet 3 treated with the above process has better corrosion resistance.

[0042] Because the positive electrode has a higher potential and is more susceptible to corrosion, and in this embodiment, electrode 3 is used as the positive electrode and the casing 1 as the negative electrode, electrode 3 is processed using the above-described S1 to S5 steps. Of course, in another embodiment, if the casing 1 is electrically connected to the positive electrode of the electrode assembly 5, i.e., the casing 1 is used as the positive electrode and electrode 3 as the negative electrode, since the negative electrode of the battery has a low potential and there is no electro-corrosion as described above, in this embodiment, the casing 1 also needs to undergo the above-described S1 to S5 steps, while electrode 3 does not require processing, and will not be repeated here.

[0043] The assembly steps for this button battery are as follows: a. Stamp and produce circular stainless steel or aluminum electrode sheets 3 and connecting rings 2 according to the specifications of button batteries; b. Process the electrode sheet 3 and the connecting ring 2 using the above-mentioned S1 to S5 process steps; c. Seal and insulate the electrode sheet 3 and the connecting ring 2 with sealing insulating glue 4 by hot pressing; d. Assemble the electrode assembly 5 into the housing 1 and inject electrolyte; e. Laser welding is used to seal the edge of the cap to the upper end of the housing 1. At the same time, resistance welding or laser penetration welding is used to weld the positive conductor 51 and the negative conductor 52 to the inner wall of the electrode sheet 3 and the inner wall of the housing 1, respectively.

[0044] This button battery features a simple and ingenious design. By welding the cap directly to the upper edge of the casing 1, it achieves excellent sealing performance, thereby improving the capacity and specific energy density of the button battery. Compared to traditional steel-cased button batteries, it effectively increases the internal volume within the same external dimensions. For batteries with a diameter of 6-16mm and a height of 3.0-6.0mm, the internal volume is effectively increased by 8%-20%. This means that the battery capacity can be increased by 8%-20% within the same external volume. This allows for the use of smaller devices when using these smaller batteries, such as hearing aids, wireless TWS Bluetooth earphones, medical endoscopes, and small smart wearables. An 8%-20% increase in battery capacity is highly beneficial for the use and promotion of these applications.

[0045] Traditional button cell batteries are sealed using a compression-type semi-sealing method. In this embodiment, the connecting ring 2 is welded to the upper edge of the housing 1, and the electrode sheet 3 is insulated and sealed to the connecting ring 2. The electrode sheet 3 and the housing 1 or the connecting ring 2 respectively form the two electrodes of the button cell battery. This allows the two electrode surfaces of a traditional button cell battery to be integrated into one side, expanding the space for fixing the battery in the device and further reducing the size of the device. The battery has a long storage life, and the fully sealed design prevents leakage of liquid or gas, resulting in excellent storage performance.

[0046] Traditional steel-cased button batteries are prone to explosions, causing injuries and damage to electrical equipment due to structural limitations when subjected to overheating. In contrast, this button battery has good explosion-proof performance. The electrode plate 3 and the connecting ring 2 are connected by a sealing insulating glue 4. When the air pressure inside the casing 1 increases and the casing 1 expands and gets heated, the sealing insulating glue 4 softens and releases pressure to achieve the purpose of explosion prevention, avoiding serious accidents caused by the expansion, explosion or fire of the button battery. The surface of the electrode plate 3 of this button battery is treated to have good corrosion resistance, which can improve the service life of the button battery. After processing the cap and / or casing 1 through steps S1 to S5, the battery manufacturing method can be applied to high-voltage positive and negative electrode systems, which can increase the capacity by 10%-20%, while the battery still has good overall performance and the battery casing will not be electrolytically corroded. The positive electrode material of traditional steel-cased batteries has a voltage of 4.2 volts and a specific capacity of 145 mAh / g, while using high-voltage materials such as 4.35 volts-4.5 volts can achieve a specific capacity of 165-200 mAh / g.

[0047] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A coin cell battery characterized by, The housing includes a bottom surface and sidewalls extending around the edge of the bottom surface. A cap is connected to the upper edge of the housing. The cap includes a connecting ring with a through hole in the middle and an electrode plate connected to the surface wall of the connecting ring by a sealing insulating adhesive and used to cover the through hole. The connecting ring is welded to the upper edge of the housing. An electrode assembly is provided inside the housing. One side of the electrode assembly is electrically connected to the inner wall of the housing through a conductor, and the other side of the electrode assembly is electrically connected to an electrode sheet through a conductor. The electrode plate has a circular structure and is coaxially arranged with the connecting ring. The diameter of the electrode plate is larger than the diameter of the through hole and smaller than the outer diameter of the connecting ring. The softening temperature of the sealing and insulating adhesive is greater than or equal to 90°C.

2. The button cell of claim 1, wherein, A stepped groove is provided around the periphery of the connecting ring, and the groove is adapted to the upper edge of the housing.

3. The button cell of claim 1 or 2, wherein, The connecting ring is connected to the upper edge of the housing by laser welding or resistance welding.

4. The button cell of claim 1, wherein, The electrode sheet is attached to the inner wall of the connecting ring.

5. The button cell of claim 1, wherein, The electrode sheet is attached to the outer wall of the connecting ring.

6. The button cell of claim 5, wherein, The inner wall of the connecting ring is provided with an insulating pad.

7. The button cell of claim 1, wherein, The sealing and insulating adhesive is made of modified polyethylene or epoxy resin.

8. The button cell of claim 1, wherein, The electrode assembly has a spiral or stacked structure; a positive electrode conductor and a negative electrode conductor are respectively connected to both sides of the electrode assembly. The positive electrode conductor is an aluminum foil with a thickness of 0.006-0.018 mm, and the negative electrode conductor is a copper foil with a thickness of 0.006-0.016 mm. The positive electrode conductor and the negative electrode conductor have a rectangular, strip, or strip structure.

9. The button cell of claim 1, wherein, The thickness of the shell is 0.1-0.25 mm, and the shell contains an electrolyte.

10. The button cell battery of claim 1, wherein, The electrode plates and connecting rings undergo surface treatment before being assembled into a button cell. The surface treatment includes the following steps: S1. Prepare a first treatment solution, wherein the first treatment solution uses water or deionized water as a solvent and further includes: hexavalent chromium compound 15-35 g / L, phosphide 25-45 g / L, and fluoride 5-15 g / L; The hexavalent chromium compound is chromium chloride and / or potassium dichromate; the phosphide is phosphoric acid and / or polyphosphoric acid; the fluoride is ammonium fluoride and / or acidic sodium fluoride. S2. Treat the electrode sheet and connecting ring with the first treatment solution. Heat the first treatment solution to 40-70°C and spray the heated first treatment solution onto the electrode sheet and connecting ring for 5-10 minutes or immerse the electrode sheet and connecting ring in the heated first treatment solution for 3-6 minutes. After treatment, rinse with tap water. S3. Prepare a second treatment solution, which uses water or deionized water as a solvent and further includes: 25-45 g / L of organic acid, 10-20 g / L of fluorine compound, and 5-15 g / L of inorganic acid. The organic acid is oxalic acid and / or acrylic acid, the fluorine compound is ammonium fluoride and / or acidic sodium fluoride, and the inorganic acid is phosphoric acid and / or hydrochloric acid. S4. The electrode sheet and connecting ring obtained in step S2 are treated again with the second treatment solution. The second treatment solution is heated to 40-70°C and sprayed onto the electrode sheet and connecting ring for 5-10 minutes or the electrode sheet and connecting ring are immersed in the heated second treatment solution for 3-6 minutes. After treatment, they are rinsed with tap water. S5. Dry the electrode sheet and connecting ring at 80-120℃ for later use.

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