Button cell

Abstract

The invention discloses a button cell, which comprises a positive electrode shell, the positive electrode shell comprises a supporting part and a corner part connected to the outer side of the supporting part, the corner part comprises a first turning section and a second turning section, the second turning section is connected between the supporting part and the first turning section, the range of a first curvature radius R1 of the first turning section is 0.5-0.85 mm, and the range of a second curvature radius R1 of the second turning section is 0.5-0.85 mm; the second curvature radius R2 of the second turning section ranges from 0.1 mm to 0.5 mm; the negative electrode shell comprises a covering part and a bent buckling part, the covering part and the supporting part are oppositely arranged, the bent buckling part has a third curvature radius R3, the range of the third curvature radius R3 is 0.1-0.3 mm, and the area, provided with the third curvature radius R3, of the bent buckling part is oppositely arranged with the first turning section; and the sealing sleeve is clamped between the corner part and the bent buckling part so as to realize sealing between the positive pole shell and the negative pole shell. According to the button cell disclosed by the invention, due to parameter setting of R1, R2 and R3, enough sealing performance is achieved between the positive electrode shell and the negative electrode cover, and the condition of liquid leakage after high temperature is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a button battery. Background Art

[0002] Button batteries are widely used as power sources in various microelectronic products due to their light weight and small size. For example, they are widely used in smart cameras, digital cameras, driving recorders, etc. Button batteries mainly include a positive electrode shell, a negative electrode cover, and a battery cell and electrolyte in a sealed cavity formed between the positive electrode shell and the negative electrode cover. The positive electrode, the separator, and the negative electrode are stacked and folded in sequence to form a battery cell.

[0003] When the battery is used as a memory power source in scenarios such as smart cameras and driving recorders, it needs to go through a special packaging process, such as reflow soldering. During this process, the battery needs to withstand a high temperature process of more than 200°C (the highest temperature is 260°C), but ordinary lithium batteries cannot withstand temperatures above 200°C. Therefore, after the battery has undergone the reflow soldering process, the internal electrolyte will decompose and produce gas in a high temperature environment. The positive electrode shell and the negative electrode cover in the prior art are easily deformed by the gas due to poor sealing, which leads to leakage and other problems during later use. Summary of the invention

[0004] In order to solve at least one problem existing in the above-mentioned prior art, according to one aspect of the present invention, a button-type battery is provided, characterized in that it comprises:

[0005] A positive electrode shell, the positive electrode shell comprising a support portion and a corner portion connected to the outside of the support portion, the corner portion comprising a first turning section and a second turning section, the second turning section being connected between the support portion and the first turning section, a first curvature radius R1 of the first turning section being in a range of 0.5-0.85 mm, and a second curvature radius R2 of the second turning section being in a range of 0.1-0.5 mm;

[0006] A negative electrode shell, comprising a cover portion and a bent buckle portion, wherein the cover portion and the support portion are arranged opposite to each other, the bent buckle portion has a third curvature radius R3, the third curvature radius R3 is in the range of 0.1-0.3 mm, and an area of ​​the bent buckle portion having the third curvature radius R3 is arranged opposite to the first turning section;

[0007] The sealing sleeve is sandwiched between the corner portion and the bent buckled portion to achieve sealing between the positive electrode shell and the negative electrode shell.

[0008] In some embodiments, from the cover portion toward the support portion, the button battery further includes a negative electrode collector, a negative electrode sheet, a separator, a positive electrode sheet, and a positive electrode collector stacked in sequence, and the separator is separated between the negative electrode sheet and the positive electrode sheet.

[0009] In some embodiments, the button cell further includes a negative electrode conductive layer, and the negative electrode conductive layer is disposed between the negative electrode sheet and the separator.

[0010] In some embodiments, the sealing sleeve is provided with a slot, the free end of the diaphragm is a curved section, and the curved section is clamped in the slot.

[0011] In some embodiments, the curved buckle portion includes a third bending section, a fourth bending section, and a fifth bending section connected in sequence, the third bending section is connected to the cover portion and has the third curvature radius R3, the fourth bending section is bent toward the diaphragm, and the fifth bending section is bent away from the diaphragm;

[0012] Wherein, the distance Z2 between the fifth turning section and the first turning section ranges from 0.15 to 0.3 mm;

[0013] The distance Z3 between the end of the fifth turning section and the inner wall of the support portion is in the range of 0.15-0.4 mm.

[0014] In some embodiments, the support portion is provided with a placement groove, and the positive electrode current collector is arranged in the placement groove.

[0015] In some embodiments, the placement groove is formed by a portion of the support portion protruding in a direction away from the covering portion.

[0016] In some embodiments, the width D1 of the placement groove is 75%-85% of the width D of the battery.

[0017] In some embodiments, the height H3 of the placement groove ranges from 0.1 to 0.3 mm.

[0018] In some embodiments, the height of the button battery is H, the distance between the first turning section and the bottom of the supporting section is H2, and the range of H2+H3 is 80%-90% of the height H.

[0019] In summary, the button battery provided by the present invention has the following technical effects:

[0020] By setting the first curvature radius R1 and the second curvature radius R2 of the first turning section and the second turning section of the positive electrode shell in the range of 0.5-0.85mm and 0.1-0.5mm respectively, and setting the third curvature radius R3 of the bent buckle portion of the negative electrode shell that matches the first turning section in the range of 0.1-0.3mm, and sealing the corner portion and the bent buckle portion by a sealing sleeve, when the button battery is assembled, the bent buckle portion of the negative electrode shell can match the pressure of the first turning section and the second turning section respectively, and press the sealing sleeve between the bent buckle portion and the first turning section and between the bent buckle portion and the second turning section, thereby ensuring the sealing of the button battery when it is subjected to high temperature in the later stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a first structural schematic diagram of a button battery according to an embodiment of the present invention;

[0022] Figure 2 for Figure 1 A second schematic diagram of the structure of the button battery in FIG.

[0023] Figure 3 for Figure 1 A partial enlarged schematic diagram of the button battery in FIG.

[0024] Figures: 100-button battery, 10-positive electrode shell, 11-support portion, 12-corner portion, 121-first turning section, 122-second turning section, 13-placing groove, 20-negative electrode shell, 21-cover portion, 22-bent button portion, 221-third turning section, 222-fourth turning section, 223-fifth turning section, 23-first corner portion, 24-second corner portion, 30-sealing sleeve, 31-card slot, 40-negative electrode collector, 50-negative electrode sheet, 60-diaphragm, 61-bending section, 70-positive electrode sheet, 80-positive electrode collector, 90-negative electrode conductive layer. DETAILED DESCRIPTION

[0025] For better understanding and implementation, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0026] In the description of the present invention, it should be noted that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0029] Embodiment 1

[0030] See also Figures 1 to 3 , a button-type battery 100 provided in an embodiment of the present invention includes a positive electrode shell 10 , a negative electrode shell 20 and a sealing sleeve 30 .

[0031] Among them, see Figure 1 and Figure 2 The positive electrode shell 10 includes a support portion 11 and a corner portion 12 connected to the outer side of the support portion 11, the corner portion 12 includes a first turning section 121 and a second turning section 122, the second turning section 122 is connected between the support portion 11 and the first turning section 121, the first curvature radius R1 of the first turning section 121 is in the range of 0.5-0.85mm, and the second curvature radius R2 of the second turning section 122 is in the range of 0.1-0.5mm; the negative electrode shell 20 includes a cover portion 21 and a bending buckle portion 22, the cover portion 21 and the support portion 11 are arranged opposite to each other, the bending buckle portion 22 has a third curvature radius R3, the third curvature radius R3 is in the range of 0.1-0.3mm, and the area where the bending buckle portion 22 is provided with the third curvature radius R3 is arranged opposite to the first turning section 121; the sealing sleeve 30 is sandwiched between the corner portion 12 and the bending buckle portion 22 to achieve sealing between the positive electrode shell 10 and the negative electrode shell 20.

[0032] The button battery 100 is constructed by setting the first curvature radius R1 and the second curvature radius R2 of the first turning section 121 and the second turning section 122 of the positive electrode shell 10 in the range of 0.5-0.85mm and 0.1-0.5mm respectively, and setting the third curvature radius R3 of the bent buckle portion 22 of the negative electrode shell 20 that matches the first turning section 121 in the range of 0.1-0.3mm, and the corner portion 12 and the bent buckle portion 22 are sealed by a sealing sleeve 30. When the button battery 100 is assembled, the bent buckle portion 22 of the negative electrode shell 20 can match the pressure of the first turning section 121 and the second turning section 122 respectively, and press the sealing sleeve 30 between the bent buckle portion 22 and the first turning section 121 and between the bent buckle portion 22 and the second turning section 122, thereby ensuring the sealing of the button battery 100 when it is subjected to high temperature in the later stage.

[0033] It can be understood that the greater the curvature, the greater the curvature of the curve, and the smaller the curvature, the smaller the curvature of the curve. The inverse of the curvature is the radius of curvature. Therefore, the smaller the radius of curvature, the greater the curvature of the curve; the greater the curvature, the smaller the curvature of the curve.

[0034] Among them, if the first curvature radius R1 of the positive electrode shell 10 exceeds 0.85 mm, the curvature at the first turning section 121 is very small, which will lead to insufficient pressure, affecting the sealing between the positive electrode shell 10, the sealing sleeve 30 and the negative electrode shell 20, and the height of the positive electrode shell 10 is easy to change, resulting in poor contact between the components inside the button battery. Therefore, the internal resistance of the button battery will increase after long-term use.

[0035] If the first curvature radius R1R1 of the positive electrode shell 10 is less than 0.5 mm, the curvature of the first turning section 121 is large, that is, the pressure on the sealing sleeve 30 is too large, which may cause the sealing sleeve 30 to be fractured, affecting the sealing performance of the button cell.

[0036] Since the second turning section 122 is connected to the support portion 11, it is equivalent to that the end of the support portion 11 needs to undergo a larger deformation so that it can bend toward the direction of the negative electrode shell 20, and bend from a straight state to form a snap-fitting part, so as to snap-fit ​​with the negative electrode shell 20. Therefore, in order to ensure the size of the snap-fitting force, that is, to ensure the sealing performance, the curvature radius of the first turning section 121 is set to be larger than the curvature radius of the second turning section 122, that is, the bending degree of the first turning section 121 is smaller than the bending degree of the second turning section 122, which not only realizes the deformation and bending of the positive electrode shell 10, but also realizes the snap-fitting of the first turning section 121 with the bent snap-fitting portion 22.

[0037] Furthermore, since the negative electrode shell 20 also needs to be bent from its original straight state to form the curved buckle portion 22, the value of the third curvature radius R3 of the curved buckle portion 22 is relatively small, that is, the negative electrode shell 20 is bent to a greater extent, and the third curvature radius R3 and the first turning section 121 cooperate to extrude the sealing sleeve 30.

[0038] Among them, the material of the positive electrode shell 10 and the negative electrode shell 20 of this embodiment can be stainless steel, and the material can be one of SUS430, SUS304, SUS316, etc. The thickness H4 of the positive electrode shell 10 and the negative electrode shell 20 is in the range of 0.1-0.2 mm, thereby ensuring the structural strength and avoiding the battery thickness after being made into a battery.

[0039] Among them, when the button battery 100 is in normal use, from the cover part 21 to the support part 11, the button battery 100 also includes a negative electrode collector 40, a negative electrode sheet 50, a separator 60, a positive electrode sheet 70 and a positive electrode collector 80 stacked in sequence, and an electrolyte filled between the positive electrode shell 10 and the negative electrode shell 20. The separator 60 blocks the negative electrode sheet 50 and the positive electrode sheet 70. Through the setting of the separator 60, the positive electrode sheet 70 and the negative electrode sheet 50 are prevented from being connected and short-circuited during use. Through the setting of the negative electrode collector 40 and the collector, the conductivity of the negative electrode sheet 50 and the positive electrode sheet 70 during the charging and discharging process is improved, and the internal resistance during the charging and discharging process is reduced.

[0040] Among them, the positive electrode sheet 70 includes a positive electrode foil and a positive electrode active material, a positive electrode conductor and a positive electrode binder coated on the positive electrode foil, wherein the positive electrode active material can be lithium manganese oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium-rich manganese base, lithium iron manganese phosphate and other materials, wherein the mass of the positive electrode active material accounts for 80-95% of the total mass of all coated materials; the positive electrode conductor is mainly graphite, acetylene black, conductive carbon black, graphite and other materials, and the mass accounts for 3-15% of the total mass of the coated material; the positive electrode binder includes polytetrafluoroethylene (PTEF), polyvinylidene fluoride (PVDF) and other commonly used lithium battery positive electrode binders, and the mass accounts for 2%-15% of the total mass of all coated materials.

[0041] Among them, the negative electrode sheet 50 includes a negative electrode foil and a negative electrode active material, a conductive agent and a binder coated on the negative electrode foil, wherein the negative electrode active material can be silicon, silicon oxide, silicon carbon and other materials, and the mass of the negative electrode active material accounts for 30-85% of the total mass of the coated material; the main components of the negative electrode conductive agent are graphite, acetylene black, conductive carbon black, and graphite, and the negative electrode conductive agent accounts for 10-50% of the total mass of all coated materials; the negative electrode binder includes polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), polyacrylic acid (PAA), polyacrylates (LA) and other materials, and the negative electrode binder accounts for 2-15% of the total mass of all coated materials.

[0042] The negative electrode current collector 40 and the positive electrode current collector 80 are composed of a conductive slurry with graphite or acetylene black as filler, and polyacrylate (LA), polyacrylic acid, polyamide imide (PAI) and the like are used as dispersants.

[0043] The separator 60 may be one of a ceramic separator, a cellulose separator, a glass fiber, a polyetheretherketone resin (PEEK), a polyester film (PET), a polyimide (PI), and a polyamide (PA). Preferably, the glass fiber in polyimide (PI) and polyamide (PA) has good high temperature resistance and a long charging cycle life, so it can be preferably used.

[0044] The material of the sealing sleeve 30 can be polyetheretherketone resin (PEEK), polyphenylene sulfide resin (PPS), polyamide resin (PA), etc. Among them, polyetheretherketone resin (PEEK), polyphenylene sulfide resin (PPS), and polyamide resin (PA) all have high thermoplasticity, and when subjected to the pressure between the positive electrode shell 10 and the negative electrode cover 20, they have good compression resistance, avoid being pressed and damaged, and ensure the sealing of the battery after high temperature. One of them can be selected for use.

[0045] The electrolyte is composed of a lithium salt and an organic solvent. The lithium salt may be at least one of lithium hexafluorophosphate (Li PF6), lithium perchlorate (LiC l O4), lithium bis(fluorosulfonamide imide) (Li FS I), lithium bis(tris(methylsulfonyl)imide) (Li TFS I), and lithium tetrafluoroborate (LiBF4), and the solvent may be at least one of propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and ethylene glycol dimethyl ether (DME). The lithium salt concentration is 1-1.5 mol / L.

[0046] See also Figure 1 In one embodiment of the present invention, since the negative electrode conductive material is worse than the positive electrode conductive material in the negative electrode system, in order to ensure the charge and discharge stability of the negative electrode side, the button battery 100 also includes a negative electrode conductive layer 90, and the negative electrode conductive layer 90 is arranged between the negative electrode sheet 50 and the separator 60. By setting the negative electrode conductive layer 90, the performance of the negative electrode sheet 50 during charge and discharge is increased, and the battery is prevented from affecting the migration efficiency of ions due to the increase of impedance after long-term use. Among them, the material of the negative electrode conductive layer can be set to graphite, acetylene black and other materials. It can be understood that a positive electrode conductive layer can also be added to the positive electrode side to further increase the charge and discharge performance of the battery, which is not limited here.

[0047] Among them, when the diaphragm 60 is set, the sealing sleeve 30 is provided with a slot 31, and the free end of the diaphragm 60 is a bent section 61, and the bent section 61 is clamped in the slot 31. In this way, by setting the slot 31 in the sealing sleeve 30, the setting position of the diaphragm 60 can be limited to prevent the diaphragm 60 from shifting, so that the diaphragm 60 can be blocked between the positive electrode sheet 70 and the negative electrode sheet 50 to prevent a short circuit between the positive electrode sheet 70 and the negative electrode sheet 50.

[0048] Among them, see Figure 1 value Figure 3The curved buckle portion 22 includes a third curved section 221, a fourth curved section 222 and a fifth curved section 223 connected in sequence, the third curved section 221 is connected to the cover portion 21 and has a third curvature radius R3, the fourth curved section 222 is curved toward the diaphragm 60, and the fifth curved section 223 is curved away from the diaphragm 60; wherein the distance Z2 between the fifth curved section 223 and the first curved section 121 is in the range of 0.15-0.4 mm; the end of the fifth curved section 223 and the support portion The distance Z3 between the inner walls of the positive electrode shell 11 is in the range of 0.15-0.4mm, that is, the sealing sleeve 30 is sandwiched between the negative electrode shell 20 and the positive electrode shell 10 and is in a compressed state. The values ​​of Z3 and Z2 are matched to ensure that the sealing sleeve 30 is in a sufficient compression between the positive electrode shell 10 and the negative electrode shell 20, so as to avoid leakage when the compression of the sealing sleeve 30 is insufficient, and to avoid the negative electrode shell 20 being deformed when the compression of the sealing sleeve 30 is too large when the battery is installed.

[0049] The value of Z2 and the value of Z3 may be set to be the same or different.

[0050] See also Figures 1 to 3 In one embodiment of the present invention, in order to facilitate the placement of the positive electrode side material, the support portion 11 is provided with a placement groove 13, and the positive electrode collector 80 is arranged in the placement groove 13. Since the button battery is installed in an inverted manner, that is, the negative electrode shell 20 is placed upside down on the support surface, and the negative electrode collector 40, the negative electrode sheet 50, the negative electrode conductive layer 90, the diaphragm 60, the positive electrode sheet 70 and the positive electrode collector 80 are arranged in sequence, and then the sealing sleeve 30 is covered on the negative electrode shell 20 and the diaphragm 60, and finally the positive electrode shell 10 is covered. In this way, by providing the placement groove 13 on the positive electrode shell 10, the positive electrode sheet 70 can be quickly positioned at the installation position of the positive electrode shell 10, thereby improving the installation efficiency.

[0051] In one embodiment of the present invention, the placement groove 13 is formed by part of the support portion 11 protruding in a direction away from the cover portion 21, that is, when forming the placement groove 13, the positive electrode case 10 can be bent by external force to form the placement groove 13 after part of the positive electrode case 10 is deformed, thereby not only facilitating the arrangement of the placement groove 13 and having high forming efficiency, but also ensuring the structural strength of the positive electrode case 10. In other embodiments, the placement groove 13 can be formed by slotting in the body of the positive electrode case 10, which can also achieve the arrangement of the placement groove 13.

[0052] Specifically, see Figure 2When the placement groove 13 is formed, the width D1 of the placement groove 13 is 75-85% of the width D of the battery. By setting this value, a pole piece and a current collector of sufficient width can be set to ensure the power supply, avoid wasting installation space when the width is set too small, and cause insufficient battery power supply; avoid inconvenience in assembly in the device when the width ratio is set too large.

[0053] Among them, the width D of the button battery of this embodiment is in the range of 4-12 mm. For example, when the width D of the button battery is set to 4 mm, the width D1 of the placement groove 13 is 80% of the width D of the battery, and the value of D1 is 4 mm*80%=3.2 mm.

[0054] Among them, see Figure 2 When the placement groove 13 is set, the height H3 of the placement groove 13 is in the range of 0.1-0.3mm. By setting the height, the height change of the button battery during the charging and discharging process can be alleviated, and the button battery is given an expansion space at a high temperature and during the charging and discharging process. By setting this range, when the height is set to a small value, the activity range of the internal pole piece is small, and when the height is set to a large value, the compression between the internal structures is insufficient, the internal resistance becomes large, and the contact between the internal structures of the battery during the charging and discharging process is poor, which affects the charging and discharging performance.

[0055] For further information, see Figure 2 The height of the button battery 100 is H, the distance between the first turning section 121 and the bottom of the support portion 11 is H2, and the range of H2+H3 is 80%-90% of the height H. Through this height setting, the second turning section 122 has a sufficient extension length to be pressed outside the sealing sleeve 30 to ensure the compression of the sealing sleeve 30. At the same time, a larger number of sealing sleeves 30 can be set to achieve a sealing effect.

[0056] Specifically, the height H of the button battery 100 of the present embodiment is in the range of 1-5 mm. For example, in some embodiments, the button battery H=5 mm, H2=4 mm, H3=0.3 mm, then H2+H3=4.3 mm, (H2+H3) / H*100%=86%, 86% is in the range of 80%-90%, meeting the requirements.

[0057] The manufacturing process of the above battery is as follows:

[0058] (1) Preparing the positive electrode case 10 and the negative electrode case 20;

[0059] (2) coating a first conductive glue and a second conductive glue on the inner surfaces of the positive electrode shell 10 and the negative electrode shell 20, respectively, and drying the first conductive glue and the second conductive glue, so that the first conductive glue and the second conductive glue after drying become the positive electrode current collector 80 or the negative electrode current collector 40;

[0060] (3) coating a third conductive adhesive on one side of the negative electrode sheet 50 and drying the third conductive adhesive so that the dried third conductive adhesive serves as the negative electrode current collector 40;

[0061] (4) The negative electrode case 20 is turned upside down, and the negative electrode sheet 50 and the separator 60 are placed in the negative electrode case 20 in sequence, with the separator 60 corresponding to the side of the negative electrode sheet 50 where the negative electrode current collector 40 is provided;

[0062] (5) Cover the sealing sleeve 30 on the negative electrode case 20 and the diaphragm 60;

[0063] (6) Placing the positive electrode sheet 70 on the separator 60;

[0064] (7) The positive electrode case 10 is placed over the negative electrode case 20 and the sealing sleeve 30, and a pressing force is applied to the positive electrode case 10 to complete the assembly of the entire button cell.

[0065] In this way, by setting the parameters of the first curvature radius R1, the second curvature radius R2, the third curvature radius R3 on the negative electrode shell 20, and the thicknesses Z2 and Z3 of the sealing sleeve 30 of the button battery, the button battery 100 of this embodiment can have better sealing after high temperature testing, which can prevent the button battery 100 from leaking, and at the same time avoid external moisture from entering the battery, causing battery performance degradation, thereby improving the battery life.

[0066] In the button battery 100, by setting the curvature radius of the first turning section 121 and the second turning section 122 of the positive electrode shell 10 in the range of 0.5-0.85 mm and the range of 0.1-0.5 mm, respectively, and setting the third curvature radius R3 of the negative electrode shell 20 in the range of 0.1-0.3 mm, when the button battery 100 is assembled, the curved buckle portion 22 of the negative electrode shell 20 can cooperate with the pressure of the first turning section 121 and the second turning section 122, respectively, and the sealing sleeve 30 is pressed between the curved buckle portion 22 and the first turning section 121 and between the curved buckle portion 22 and the second turning section 122, thereby ensuring the sealing of the button battery 100 when subjected to high temperature in the later stage; by A negative electrode conductive layer 90 is also arranged between the two portions of the sealing sleeve 30 to ensure the conductivity of the negative electrode side and resist the impedance generated by the button battery after long-term use; by setting the height range of the two positions of the sealing sleeve 30 within the range of 0.15-0.4 mm, the compression amount of the sealing sleeve 30 is ensured, thereby ensuring the sealing performance; by setting the placement groove 13 on the positive electrode shell 10, it is convenient to locate the placement position of the positive electrode sheet 70 during assembly, thereby improving the installation efficiency; by setting the overall height H2+H3 of the positive electrode shell 10 within the range of 80%H-90%H of the entire battery height H, the second turning section 122 has a sufficient extension length to be pressed against the outside of the sealing sleeve 30, thereby ensuring the compression of the sealing sleeve 30, and at the same time, a larger number of sealing sleeves 30 can be arranged to achieve a sealing effect.

[0067] Therefore, within the above range, the battery still has good sealing even after high temperature testing, which can prevent the electrolyte from leaking and volatilizing, or external moisture from entering the battery, causing battery performance degradation.

[0068] Embodiment 2:

[0069] This embodiment provides a button cell 100 prepared using the above parameters and manufacturing method, specifically:

[0070] (1) The diameter D of the button battery 100 is 6.8 mm, the height H is 2.1 mm, H2 is 1.5 mm, H3 is 0.2 mm, R1 is 0.75 mm, the compression amount Z2 of the sealing sleeve 30 between the first turning section 121 and the fifth turning section 2412 is 0.35 mm, and the compression amount Z3 of the sealing sleeve 30 between the end of the negative electrode shell 20 and the support portion 11 of the positive electrode shell 10 is 0.3 mm;

[0071] (2) In the positive electrode sheet 70, lithium manganese oxide is used as the positive electrode active material, graphite is used as the positive electrode conductive agent, and polyacrylic acid is used as the positive electrode binder. The mixture is mixed in a weight ratio of 90:8:2. 95.3 mg of the mixed powder is pressed into a disc with a diameter of 3.8 mm. The disc is used as the positive electrode sheet 70 for subsequent battery assembly.

[0072] (3) The negative electrode sheet 50 uses silicon oxide as the negative electrode active material, graphite as the negative electrode conductive agent, and polyacrylic acid as the negative electrode binder, which are mixed in a weight ratio of 70:28:2. 5.1 mg of the mixed powder is pressed into a disc with a diameter of 3.8 mm. The disc is used as the negative electrode sheet 50 for subsequent battery assembly;

[0073] (4) The electrolyte is 1 mol / L lithium bis(fluorosulfonyl)imide (LiFS I), and the solvent is a mixture of propylene carbonate (PC), ethylene carbonate (EC), and ethylene glycol dimethyl ether (DME), with a weight ratio of 1:1:2;

[0074] (5) The diaphragm 60 is made of polyimide (PI), and the sealing sleeve 30 is made of polyphenylene sulfide resin (PPS).

[0075] Comparative Example 1:

[0076] Comparative Example 1 provides a button cell 100 manufactured according to the above manufacturing method, but some parameters of the positive electrode shell 10 or the negative electrode shell 20 are different from those in Example 2, wherein:

[0077] (1) The diameter D of the button battery 100 is 6.8 mm, the height H is 2.1 mm, H2 is 1.5 mm, H3 is 0.2 mm, R1 is 0.5 mm (smaller than R1 of the second embodiment), R2 is 0.75 mm, the compression amount Z2 of the sealing sleeve 30 between the first turning section 121 and the fifth turning section 2412 is 0.3 mm (smaller than Z2 of the second embodiment), and the compression amount Z3 of the sealing sleeve 30 between the end of the negative electrode shell 20 and the support portion 11 of the positive electrode shell 10 is 0.25 mm (smaller than Z3 of the second embodiment);

[0078] (2) In the positive electrode sheet 70, lithium manganese oxide is used as the positive electrode active material, graphite is used as the positive electrode conductive agent, and polyacrylic acid is used as the positive electrode binder. The mixture is mixed in a weight ratio of 90:8:2. 95.3 mg of the mixed powder is pressed into a disc with a diameter of 3.8 mm. The disc is used as the positive electrode sheet 70 and the battery is assembled.

[0079] (3) The negative electrode sheet 50 uses silicon oxide as the negative electrode active material, graphite as the negative electrode conductive agent, and polyacrylic acid as the negative electrode binder, and is mixed in a weight ratio of 70:28:2. 5.1 mg of the mixed powder is pressed into a disc with a diameter of 3.8 mm. The disc is used as the negative electrode sheet 50 for the subsequent battery assembly;

[0080] (4) The electrolyte is 1 mol / L lithium bis(fluorosulfonyl)imide (LiFSI), and the solvent is a mixture of propylene carbonate (PC), ethylene carbonate (EC), and ethylene glycol dimethyl ether (DME), with a weight ratio of 1:1:2.

[0081] Comparative Example 2:

[0082] Comparative Example 2 provides a button cell 100 manufactured according to the above manufacturing method, but some parameters of the positive electrode shell 10 or the negative electrode shell 20 are different from those in Example 2, wherein:

[0083] (1) The diameter D of the buckle is 6.8 mm, the height H is 2.1 mm, H2 is 1.7 mm (greater than H2 in the second embodiment), H3 is 0.2 mm, R1 is 0.85 mm (greater than R1 in the first embodiment), the compression amount Z2 of the sealing sleeve 30 between the first turning section 121 and the fifth turning section 2412 is 0.35 mm, and the compression amount Z3 of the sealing sleeve 30 between the end of the negative electrode shell 20 and the support portion 11 of the positive electrode shell 10 is 0.3 mm;

[0084] (2) The positive electrode sheet 70 uses lithium manganese oxide as the positive electrode active material, graphite as the positive electrode conductive agent, and polyacrylic acid as the positive electrode binder, which are mixed in a weight ratio of 90:8:2. 95.3 mg of the mixed powder is pressed into a disc with a diameter of 3.8 mm. The disc is used as the positive electrode sheet 70 for subsequent battery assembly;

[0085] (3) The negative electrode sheet 50 uses silicon oxide as the negative electrode active material, graphite as the negative electrode conductive agent, and polyacrylic acid as the negative electrode binder. The mixture is mixed in a weight ratio of 70:28:2, and 5.1 mg of the mixed powder is pressed into a disc with a diameter of 3.8 mm. The disc is used as the negative electrode sheet 50 for the subsequent battery assembly;

[0086] (4) The electrolyte is 1 mol / L lithium bis(fluorosulfonyl)imide (LiFS I), and the solvent is a mixture of propylene carbonate (PC), ethylene carbonate (EC), and ethylene glycol dimethyl ether (DME), with a weight ratio of 1:1:2;

[0087] (5) The diaphragm 60 is made of polyimide (PI), and the sealing material is made of polyphenylene sulfide resin (PPS).

[0088] Furthermore, the button cells 100 prepared in the above-mentioned Example 2, Comparative Example 1 and Comparative Example 2 were tested by the following same temperature and charge-discharge test method:

[0089] (1) Discharge the button cell 100 at room temperature to an initial capacity Q0, and record the height H and internal resistance of the button cell 100;

[0090] (2) After the button cell 100 has been subjected to the temperature of the reflow soldering process, a height H and an internal resistance test are performed, and the discharge capacity of the button cell 100 after the reflow soldering process is recorded as the capacity Q; wherein the reflow soldering process conditions are: the button cell 100 is maintained at 160° C. for 10 min, and then maintained at 260° C. for 30 s;

[0091] (4) Calculate the capacity retention rate of the button battery 100: capacity retention rate = discharge capacity after reflow soldering / initial discharge capacity = Q / Q0x100%;

[0092] (5) After the reflow test of the button cell 100, observe whether there is liquid seepage on the surface of the button cell 100, and compare the height H and internal resistance of the button cell 100 before and after the reflow test. The height change = the initial height H of the button cell 100 - the height H of the button cell 100 after the reflow test.

[0093] Among them, the capacity retention rate is above 90%, which means that the battery performance has no significant change; the change in internal resistance is acceptable within 50Ω, and the change in the height H of the button battery 100 is within the standard range within 0.02mm.

[0094] Among them, the parameters of the button batteries 100 prepared in Example 2, Comparative Example 1 and Comparative Example 2 are compared as follows:

[0095]

[0096] (1) The values ​​of H2, R1, R2, R3, Z2, and Z3 of the button cell 100 in Example 2 are within the optimal range listed in Example 1. The internal resistance of the battery changes slightly before and after reflow soldering (Δ=420-408=12Ω), and the button cell 100 shows no obvious liquid leakage, indicating that the button cell 100 still has good sealing after high-temperature treatment. At the same time, the capacity retention rate of the button cell 100 is above 90%, which can meet the capacity requirements of the button cell 100.

[0097] (2) Compared with Example 2, H2 of Comparative Example 1 is lower than the preferred range, that is, the bending extension length of the positive electrode shell 10 for sealing is insufficient, and R1 is 0.5 mm. Although it is smaller than R1 of Example 2, it is within the preferred range. After the reflow soldering process, liquid appears on the surface of the button battery 100. Therefore, the reason may be that during the sealing process of the button battery 100, the pressure of the first turning section 121 of the positive electrode shell 10 is too large, which may fracture the sealing sleeve 30, thereby affecting the thermoplasticity of the sealing sleeve 30, causing the electrolyte inside the button battery 100 to leak or external moisture to enter the button battery 100, resulting in an increase in the internal resistance of the button battery 100 and a decrease in the capacity retention rate.

[0098] (3) In comparative example 2, the distance between the end of the first turning section 121 in the button battery 100 and the outer wall of the support portion 21 exceeds the preferred range. When R2 is 0.75 mm, which is greater than the optimal preferred value of R2 of 0.5, there is no obvious liquid seepage on the surface of the button battery 100, but the internal resistance changes greatly. It may be that the excessively large H2 causes poor contact inside the button battery 100. The increase in the internal resistance of the battery will also cause the battery capacity retention rate to be lower than 90%.

[0099] In summary, the test results of Example 2, Comparative Example 1 and Comparative Example 2 respectively show that the button battery 100 prepared according to the parameters of the first curvature radius R1, the second curvature radius R2, the third curvature radius R3 on the negative electrode shell 20, and Z2 and Z3 of the sealing sleeve 30 of the present invention still has good sealing after being exposed to a high temperature environment, and can avoid the problem of leakage. At the same time, the electrical performance of the button battery 100 is not significantly deteriorated, thereby ensuring the performance of the button battery 100.

[0100] The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical schemes composed of any combination of the above-mentioned technical features. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also regarded as the protection scope of the present invention.

Claims

1. A button cell (100), characterized in that: include: A positive electrode shell (10), the positive electrode shell (10) comprising a support portion (11) and a corner portion (12) connected to the outside of the support portion (11), the corner portion (12) comprising a first turning section (121) and a second turning section (122), the second turning section (122) being connected between the support portion (11) and the first turning section (121), a first curvature radius R1 of the first turning section (121) being in a range of 0.5-0.85 mm, and a second curvature radius R2 of the second turning section (122) being in a range of 0.1-0.5 mm; A negative electrode shell (20), comprising a cover portion (21) and a bent buckle portion (22), wherein the cover portion (21) and the support portion (11) are arranged opposite to each other, the bent buckle portion (22) has a third curvature radius R3, the third curvature radius R3 ranges from 0.1 to 0.3 mm, and a region of the bent buckle portion (22) having the third curvature radius R3 is arranged opposite to the first turning section (121); A sealing sleeve (30) is sandwiched between the corner portion (12) and the bent buckled portion (22) to achieve sealing between the positive electrode shell (10) and the negative electrode shell (20).

2. The button battery (100) according to claim 1, characterized in that: In the direction from the cover portion (21) to the support portion (11), the button battery (100) further comprises a negative electrode current collector (40), a negative electrode sheet (50), a separator (60), a positive electrode sheet (70) and a positive electrode current collector (80) stacked in sequence, wherein the separator (60) is separated between the negative electrode sheet (50) and the positive electrode sheet (70).

3. The button cell (100) according to claim 2, characterized in that: The button-type battery (100) further comprises a negative electrode conductive layer (90), wherein the negative electrode conductive layer (90) is arranged between the negative electrode sheet (50) and the separator (60).

4. The button cell (100) according to claim 2 or 3, characterized in that: The sealing sleeve (30) is provided with a slot (31), and the free end of the diaphragm (60) is a bent section, and the bent section is locked in the slot (31).

5. The button cell according to claim 4, characterized in that: The curved buckling portion (22) comprises a third bending section (221), a fourth bending section (222) and a fifth bending section (223) which are connected in sequence, the third bending section (221) is connected to the cover portion (21) and has the third curvature radius R3, the fourth bending section (222) is bent in the direction of the diaphragm (60), and the fifth bending section (223) is bent in the direction away from the diaphragm (60); Wherein, the distance Z2 between the fifth turning section (223) and the first turning section (121) is in the range of 0.15-0.3 mm; The distance Z3 between the end of the fifth turning section (223) and the inner wall of the support portion (11) is in the range of 0.15-0.4 mm.

6. The button cell (100) according to claim 2 or 3, characterized in that: The support portion (11) is provided with a placement groove (13), and the positive electrode current collector (80) is arranged in the placement groove (13).

7. The button cell (100) according to claim 6, characterized in that: The placement groove (13) is formed by a portion of the support portion (11) protruding in a direction away from the cover portion (21).

8. The button cell (100) according to claim 6, characterized in that: The width D1 of the placement groove (13) is 75%-85% of the width D of the battery.

9. The button cell (100) according to claim 7 or 8, characterized in that: The height H3 of the placement groove (13) is in the range of 0.1-0.3 mm.

10. The button cell (100) according to claim 9, characterized in that: The height of the button battery (100) is H, the distance between the first bending section (121) and the bottom of the supporting section is H2, and the range of H2+H3 is 80%-90% of the height H.

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