Button Cells and Their Manufacturing Methods

Abstract

This invention provides a coin cell battery and its manufacturing method. The method includes providing a first housing, the first housing including a conductive layer and an insulating layer, a first mounting groove in the middle of the first housing, a through hole in the insulating layer within the first mounting groove, and a conductive layer exposed outside the insulating layer through the through hole. An active material layer is coated on the surface of the conductive layer. A second electrode is inserted into a second mounting groove of a second housing, and a separator is placed inside. The edges of the first housing and the second housing are sealed, and the first mounting groove and the second mounting groove are sealed to form a mounting cavity, thus obtaining a coin cell battery. By pre-coating the active material layer onto the surface of the conductive layer of the first housing, the problems of uneven electrode thickness and active material layer detachment caused by rolling the active material layer onto the electrode are avoided, resulting in a more stable specific capacity and effectively improving battery performance.

Description

Technical Field

[0001] This invention relates to the field of battery manufacturing technology, and in particular to a button cell battery and its manufacturing method. Background Technology

[0002] Coin cells are mainly composed of positive or negative electrode plates, separators, electrolytes, lithium plates, and casings. Their casings are generally made of steel. Coin cells are commonly used for tests such as active capacity and initial efficiency. However, due to their high internal resistance and poor electrolyte retention caused by their structure, it is difficult to use coin cells for other tests, thus limiting their application scenarios.

[0003] The current manufacturing process for button cells involves coating active materials onto the electrodes using a push-type coater, drying the coating, and then rolling it. Following this, the electrodes are stamped and assembled. This method has several significant problems: first, the areal density varies greatly across different areas of the coated electrode, resulting in uneven electrode thickness after rolling; second, the active material layer coated on the edges of the electrode is prone to peeling off during stamping; and third, the weight of the electrode foil also fluctuates, leading to large variations in the measured specific capacity or initial efficiency data. Summary of the Invention

[0004] Therefore, it is necessary to provide a button cell and its manufacturing method to address the aforementioned technical problems.

[0005] A method for manufacturing a button cell battery, comprising:

[0006] A first housing is provided, wherein the first housing includes a conductive layer and an insulating layer covering the outside of the conductive layer, a first mounting groove is provided in the middle of the first housing, a through hole is formed in the insulating layer in the first mounting groove, the conductive layer is exposed outside the insulating layer through the through hole in the first mounting groove, an active material layer is coated on the surface of the conductive layer within the range of the first mounting groove, and a first electrode tab is connected to one side of the first housing, the first electrode tab being connected to the conductive layer;

[0007] A second electrode is provided, and one side of the second electrode is connected to a second electrode tab;

[0008] A second housing is provided, wherein a second mounting groove is provided in the middle of the second housing;

[0009] The second electrode is installed into the second mounting groove of the second housing, electrolyte is added into the second mounting groove, and then a diaphragm is placed in, wherein the width of the diaphragm is greater than the width of the second mounting groove.

[0010] Add electrolyte to the first mounting tank;

[0011] The edges of the first housing and the second housing are sealed, and the first mounting groove and the second mounting groove are sealed to form a mounting cavity, thus obtaining a button cell battery.

[0012] In one embodiment, the step of encapsulating the edges of the first housing and the second housing, and sealing the first mounting groove and the second mounting groove to form a mounting cavity to obtain a button cell includes:

[0013] Align the first mounting groove of the first housing with the second mounting groove, use the diaphragm to isolate the second electrode and the active material layer, encapsulate the edges of the first housing and the second housing, and seal the first mounting groove and the second mounting groove to form a mounting cavity, thus obtaining a button cell.

[0014] In one embodiment, the step of providing the second housing is further included prior to:

[0015] Provide a second prototype shell;

[0016] The second prototype shell is stamped to form a second mounting groove in the middle of the second prototype shell, thereby obtaining the second shell, wherein the width of the second mounting groove is greater than the width of the first mounting groove.

[0017] In one embodiment, the step of providing the first housing is further included prior to:

[0018] A first prototype housing is provided, wherein the first prototype housing includes a conductive layer and an insulating layer covering the outside of the conductive layer, the insulating layer has a through hole in the middle of the first prototype housing, and the conductive layer is exposed to the insulating layer through the through hole;

[0019] The first prototype shell is stamped to form a first mounting groove in the middle of the first prototype shell, thereby obtaining the first shell, wherein the range of the first mounting groove coincides with the range of the through hole;

[0020] An active substance slurry is coated on the surface of the conductive layer within the first mounting groove. After the active substance slurry is cured, an active substance layer is formed on the surface of the conductive layer.

[0021] In one embodiment, the step of providing the first housing is further included prior to:

[0022] A first prototype housing is provided, wherein the first prototype housing includes a conductive layer and an insulating layer covering the outside of the conductive layer, the insulating layer has a through hole in the middle of the first prototype housing, and the conductive layer is exposed to the insulating layer through the through hole;

[0023] An active substance slurry is coated on the surface of the conductive layer exposed within the through-hole area. After the active substance slurry is cured, an active substance layer is formed on the surface of the conductive layer.

[0024] The first prototype housing is stamped to form a first mounting groove in the middle of the first prototype housing, thereby obtaining the first housing, wherein the range of the first mounting groove coincides with the range of the through hole.

[0025] In one embodiment, the active material slurry includes an active material, a conductive agent, a binder, and a dispersant, and the mass ratio of the active material, the conductive agent, the binder, and the dispersant is 95.0:2.0:1.5:1.5.

[0026] In one embodiment, the conductive layer comprises an aluminum layer and the insulating layer comprises a PE layer.

[0027] In one embodiment, the second electrode is a lithium sheet, and the second tab is a nickel strip tab, wherein the lithium sheet is bonded to the nickel strip tab by conductive adhesive.

[0028] In one embodiment, the step of encapsulating the edges of the first housing and the second housing, and sealing the first mounting groove and the second mounting groove to form a mounting cavity to obtain a button cell includes:

[0029] A conductive wire is installed on the side of the first housing facing the diaphragm, with a first end of the conductive wire connected to the insulating layer and a second end of the conductive wire extending to the outside of the first housing;

[0030] Align the first mounting groove of the first housing with the second mounting groove, use the diaphragm to isolate the second electrode and the active material layer, encapsulate the edges of the first housing and the second housing, seal the first mounting groove and the second mounting groove to form a mounting cavity, and expose at least part of the conductive wire, the first electrode tab and the second electrode tab in the mounting cavity to obtain a button cell.

[0031] A button cell battery includes: a first casing, a second casing, a separator, and a second electrode.

[0032] The first housing includes a conductive layer and an insulating layer covering the outside of the conductive layer. A first mounting groove is provided in the middle of the first housing. The insulating layer has a through hole in the first mounting groove. The conductive layer is exposed outside the insulating layer through the through hole in the first mounting groove. An active material layer is coated on the surface of the conductive layer within the range of the first mounting groove. A first electrode is connected to one side of the first housing. The first electrode is connected to the conductive layer.

[0033] One side of the second electrode plate is connected to the second electrode tab;

[0034] A second mounting groove is provided in the middle of the second housing;

[0035] The edges of the first housing and the second housing are sealed together, the first mounting groove and the second mounting groove are sealed to form a mounting cavity, the first electrode tab and the second electrode tab are at least partially exposed in the mounting cavity, the diaphragm and the second electrode are disposed in the mounting cavity, wherein the second electrode is disposed in the second mounting groove, the diaphragm is disposed on the side of the second electrode facing away from the second housing, and the diaphragm isolates the active material layer and the second electrode.

[0036] The aforementioned button cell and its manufacturing method pre-coat the surface of the conductive layer of the first casing with an active material layer, and use the conductive layer of the first casing as an electrode. This avoids the problems of uneven electrode thickness and active material layer shedding caused by the active material layer being coated on the electrode and rolled. It effectively avoids the problem of large fluctuations in specific capacity, making the specific capacity more stable and thus effectively improving battery performance. Attached Figure Description

[0037] Figure 1 This is a flowchart illustrating a button cell manufacturing method in one embodiment;

[0038] Figure 2 This is a schematic diagram of the structure of the first casing of a button cell in one embodiment, taken from one direction.

[0039] Figure 3 This is a schematic diagram of the structure of the first casing of the button cell in one embodiment from another direction;

[0040] Figure 4 This is a schematic diagram of the structure of the second electrode of a button cell in one embodiment;

[0041] Figure 5 This is a schematic diagram of the assembly structure of a button cell in one direction in one embodiment;

[0042] Figure 6 This is a schematic diagram of the assembly structure of a button cell in another direction in one embodiment;

[0043] Figure 7 This is a schematic diagram of the structure of the first casing of the button cell in one direction in another embodiment.

[0044] Explanation of reference numerals in the attached figures:

[0045] 10. Button cell; 210. First casing; 220. Second casing; 320. Second electrode; 410. Separator; 211. Conductive layer; 212. Insulating layer; 510. First tab; 520. Second tab; 213. First mounting groove; 221. Second mounting groove; 250. Active material layer; 610. Conductive wire; Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0047] In one embodiment, such as Figure 1 As shown, a method for manufacturing a button cell battery is provided, comprising:

[0048] Step 110: Provide a first housing, wherein the first housing includes a conductive layer and an insulating layer covering the outside of the conductive layer, a first mounting groove is provided in the middle of the first housing, the insulating layer has a through hole in the first mounting groove, the conductive layer is exposed outside the insulating layer through the through hole in the first mounting groove, the surface of the conductive layer is coated with an active material layer within the range of the first mounting groove, and a first electrode tab is connected to one side of the first housing, the first electrode tab being connected to the conductive layer;

[0049] Step 120: Provide a second electrode plate, one side of which is connected to a second electrode tab;

[0050] Step 130: Provide a second housing, wherein a second mounting groove is provided in the middle of the second housing;

[0051] Step 140: The second electrode is installed into the second mounting groove of the second housing, electrolyte is added into the second mounting groove, and then a diaphragm is placed in, wherein the width of the diaphragm is greater than the width of the second mounting groove.

[0052] Step 150: Add electrolyte to the first mounting tank;

[0053] Step 160: The edges of the first housing and the second housing are sealed, and the first mounting groove and the second mounting groove are sealed to form a mounting cavity, thereby obtaining a button cell battery.

[0054] In this embodiment, the insulating layer of the first housing includes a PE (Polyethylene) layer, and the conductive layer is a metal layer, such as an aluminum layer. In this embodiment, the first housing is an aluminum-plastic film, including a first PE layer, an aluminum layer, and a second PE layer. The first and second PE layers cover the outside of the aluminum layer. In other embodiments, the first housing may also use other materials for the insulating and conductive layers, not limited to aluminum-plastic film. A first mounting groove is formed by a recess in the first housing. The insulating layer is hollowed out in the first mounting groove to form a through hole, allowing the conductive layer to be exposed through the through hole. An active material layer is disposed on the exposed surface of the conductive layer.

[0055] In this embodiment, the conductive layer of the first housing serves as the first electrode of the battery. Since the active material layer is pre-coated on the surface of the conductive layer of the first housing, it is not necessary to coat the active material layer onto the electrode sheet. This avoids the problem of uneven thickness of the electrode sheet after rolling due to uneven coating of the active material layer and the problem of the active material layer falling off after rolling.

[0056] In this embodiment, since the width of the diaphragm is greater than the width of the second mounting groove, and since the second electrode is located in the second mounting groove, the diaphragm can fully isolate the second electrode from the conductive layer of the first housing.

[0057] In this embodiment, the conductive layer of the first housing and the second electrode can be either a positive or a negative electrode. For example, the conductive layer of the first housing can be a positive electrode and the second electrode can be a negative electrode, or vice versa. In one embodiment, the second electrode is a lithium sheet. In this embodiment, the conductive layer of the first housing serves as the positive electrode and the second electrode is a negative lithium sheet. The second electrode can also be called a lithium sheet. The second tab is a nickel strip tab. In this embodiment, the lithium sheet is bonded to the nickel strip tab with conductive adhesive. Specifically, the nickel strip tab is used to lead out conductivity. The conductive adhesive includes an adhesive and a conductive filler. The adhesive includes at least one of epoxy resin, silicone resin, polyimide resin, phenolic resin, polyurethane, and acrylic resin. The conductive adhesive is water-free. The conductive filler can be powder of gold, silver, copper, aluminum, zinc, iron, nickel, and / or graphite and some conductive compounds, but is not limited to these.

[0058] In this embodiment, a first housing is connected to a first tab, and a second electrode is connected to a second tab. When the first housing and the second housing enclose the second electrode and the separator in the mounting cavity, the first tab and the second tab are exposed on the outside of the first housing and the second housing. Then, the first housing and the second housing are thermo-encapsulated to obtain a button cell.

[0059] In the above embodiments, by pre-coating the active material layer onto the surface of the conductive layer of the first housing, and using the conductive layer of the first housing as an electrode, the problems of uneven electrode thickness and active material layer detachment caused by the active material layer being coated on the electrode and rolled are avoided. This effectively avoids the problem of large fluctuations in specific capacity, making the specific capacity more stable and thus effectively improving battery performance.

[0060] In one embodiment, the cross-sectional shape of the first mounting groove is trapezoidal. In this embodiment, the cross-sectional shape of the first mounting groove in the direction perpendicular to the conductive layer is trapezoidal. In this embodiment, the depth of the first mounting groove gradually increases from the edge to the center, and the sidewalls of the first mounting groove gradually slope towards the bottom of the first mounting groove from the outside to the inside. This makes the cross-section of the first mounting groove trapezoidal. For the first housing after coating the active material layer and then stamping, the conductive layer can be gradually deformed from the outside to the inside during the stamping process. The waist of the trapezoid allows the depth of the first mounting groove to gradually increase, avoiding large-angle (90-degree) deformation of the conductive layer, thereby effectively preventing the active material layer on the conductive layer from falling off during stamping.

[0061] In one embodiment, the through-hole is circular. In this embodiment, the cross-sectional shape of the first mounting groove in the direction parallel to the conductive layer is circular. In this embodiment, the circular through-hole and the first mounting groove can better fit the shape of the circular second electrode and the diaphragm. In other embodiments, the through-hole can also be triangular, square, or regular polygonal, and the cross-sectional shape of the first mounting groove in the direction parallel to the conductive layer can also be triangular, square, or regular polygonal.

[0062] In one embodiment, the step of encapsulating the edges of the first housing and the second housing, and sealing the first mounting groove and the second mounting groove to form a mounting cavity to obtain a button cell includes:

[0063] Align the first mounting groove of the first housing with the second mounting groove, use the diaphragm to isolate the second electrode and the active material layer, encapsulate the edges of the first housing and the second housing, and seal the first mounting groove and the second mounting groove to form a mounting cavity, thus obtaining a button cell.

[0064] In this embodiment, the opening direction of the first mounting groove of the first housing is oriented toward the opening direction of the second mounting groove so that the first mounting groove and the second mounting groove can be aligned. Then, the first housing and the second housing are thermoplastically encapsulated to seal the second electrode, the separator and the electrolyte in the mounting cavity. The separator isolates the second electrode and the conductive layer that serves as the first electrode, thereby obtaining a coin cell.

[0065] In one embodiment, prior to the step of providing the second housing, the method further includes: providing a second prototype housing; stamping the second prototype housing to form a second mounting groove in the middle of the second prototype housing to obtain the second housing, wherein the width of the second mounting groove is greater than the width of the first mounting groove.

[0066] In this embodiment, the second prototype housing includes a conductive prototype layer and an insulating prototype layer covering the outside of the conductive prototype layer. For example, the second prototype housing can be an aluminum-plastic film. Alternatively, the second prototype housing may include a third PE layer, an aluminum prototype layer, and a fourth PE layer, with the third and fourth PE layers covering the outside of the aluminum prototype layer. In other embodiments, the first housing may also use other materials for the insulating and conductive layers, not limited to aluminum-plastic film. In this embodiment, the second prototype housing is stamped to form a second mounting groove with a width greater than the first mounting groove, and a depth less than the thickness of the second electrode. Thus, when the second electrode is placed in the second mounting groove, the second electrode protrudes at least partially into the second mounting groove. A diaphragm is then placed on the second electrode. Since the width of the diaphragm is greater than the width of the second mounting groove, the diaphragm effectively blocks the second electrode, isolating the second electrode from the conductive layer of the first housing.

[0067] In one embodiment, the step of providing the first housing is preceded by:

[0068] A first prototype housing is provided, wherein the first prototype housing includes a conductive layer and an insulating layer covering the outside of the conductive layer, the insulating layer has a through hole in the middle of the first prototype housing, and the conductive layer is exposed to the insulating layer through the through hole;

[0069] The first prototype shell is stamped to form a first mounting groove in the middle of the first prototype shell, thereby obtaining the first shell, wherein the range of the first mounting groove coincides with the range of the through hole;

[0070] An active substance slurry is coated on the surface of the conductive layer within the first mounting groove. After the active substance slurry is cured, an active substance layer is formed on the surface of the conductive layer.

[0071] In this embodiment, the first prototype shell includes a conductive layer and an insulating layer covering the outside of the conductive layer. In this embodiment, the first prototype shell is an aluminum-plastic film, including a first PE layer, an aluminum layer, and a second PE layer. The first and second PE layers cover the outside of the aluminum layer. Before providing the first prototype shell, the first PE layer in the middle of the first prototype shell is removed to form a through hole in the middle of one side of the first prototype shell, allowing the aluminum layer to be exposed to the insulating layer through the through hole. Subsequently, the middle of the first prototype shell is stamped to form a first mounting groove in the middle of the first prototype shell, resulting in the first shell. The position and range of the first mounting groove coincide with the position and range of the through hole. In this embodiment, a cylindrical pressure post is used, first pressing down and then rotating a roller to press out the first mounting groove on the first prototype shell.

[0072] Subsequently, an active material slurry is coated onto the surface of the exposed conductive layer within the first mounting groove. The first housing is then dried in an oven at a temperature below 120°C, thereby forming an active material layer on the surface of the conductive layer. In this embodiment, the first prototype housing is first stamped, followed by the coating with the active material slurry to form the active material layer. This effectively prevents the active material layer from detaching during the stamping process, thus ensuring the integrity of the active material layer.

[0073] In one embodiment, the step of providing the first housing is preceded by:

[0074] A first prototype housing is provided, wherein the first prototype housing includes a conductive layer and an insulating layer covering the outside of the conductive layer, the insulating layer has a through hole in the middle of the first prototype housing, and the conductive layer is exposed to the insulating layer through the through hole;

[0075] An active substance slurry is coated on the surface of the conductive layer exposed within the through-hole area. After the active substance slurry is cured, an active substance layer is formed on the surface of the conductive layer.

[0076] The first prototype housing is stamped to form a first mounting groove in the middle of the first prototype housing, thereby obtaining the first housing, wherein the range of the first mounting groove coincides with the range of the through hole.

[0077] In this embodiment, the same first prototype housing as in the previous embodiment is provided. The difference from the previous embodiment is that, in this embodiment, an active material slurry is first coated on the surface of the exposed conductive layer. After drying, an active material layer is formed on the surface of the conductive layer. Subsequently, the middle part of the first prototype housing is stamped, and the stamping range coincides with the position and range of the through hole, thereby forming a first mounting groove on the first housing whose position and range coincide with the through hole.

[0078] In one embodiment, the active substance slurry comprises an active substance, a conductive agent, a binder, and a dispersant, and the mass ratio of the active substance, the conductive agent, the binder, and the dispersant is 95.0:2.0:1.5:1.5.

[0079] In one embodiment, the step of encapsulating the edges of the first housing and the second housing, and sealing the first mounting groove and the second mounting groove to form a mounting cavity to obtain a button cell includes:

[0080] A conductive wire is installed on the side of the first housing facing the diaphragm, with a first end of the conductive wire connected to the insulating layer and a second end of the conductive wire extending to the outside of the first housing;

[0081] Align the first mounting groove of the first housing with the second mounting groove, use the diaphragm to isolate the second electrode and the active material layer, encapsulate the edges of the first housing and the second housing, seal the first mounting groove and the second mounting groove to form a mounting cavity, and expose at least part of the conductive wire, the first electrode tab and the second electrode tab in the mounting cavity to obtain a button cell.

[0082] In this embodiment, the conductive wire serves as the third electrode of the coin cell, providing signal transmission to monitor the electrochemical behavior of the battery's active materials, including potential and plateau. Furthermore, this conductive wire can be used to extend other tests. In this embodiment, the conductive wire is first installed on the first housing. The first end of the conductive wire is connected to the insulating layer of the first housing, and the second end of the conductive wire extends to the outside of the first housing. During the encapsulation of the first and second housings, the second end of the conductive wire, the end of the first tab furthest from the first housing, and the end of the second tab furthest from the second electrode are exposed in the mounting cavity, allowing these ends to extend to the outside of the first and second housings for easy connection to external electrical components. Thus, the battery signal can be monitored through this conductive wire. In one embodiment, the conductive wire is a copper wire with a diameter of 30-60 μm. In this embodiment, electrolyte-resistant tape is used to fix and bond the copper wire to the insulating layer of the first housing, preventing the copper wire from connecting to the active material layer. After encapsulation, a three-electrode coin cell is formed. The copper wire allows for the monitoring of the electrochemical behavior of the battery's active materials, such as potential and plateau.

[0083] The following are specific examples:

[0084] Example 1:

[0085] 1. Active substance slurry preparation: The slurry is prepared by mixing active substance: conductive agent: binder: dispersant = 95.0: 2.0: 1.5: 1.5, but is not limited to this formula.

[0086] 2. Weigh shell A, and use a dropper to transfer the slurry onto shell A. Shell A has a lead-out tab for conductivity. It is then dried in an oven below 120°C to produce a specially shaped electrode sheet. The weight of the dressing is then measured again. This shell A (e.g.) Figure 1 The material is mainly aluminum-plastic film (usually a structure of PE layer + aluminum + PE layer, but not limited to this type of aluminum-plastic film). The inner PE layer has a hollowed-out circular area with a diameter of 'a', which is obtained by punching a hole with a depth of 'HA' using a stamping device. The hollowed-out area is not limited to a circle, but can also be triangular or square, etc.

[0087] 3. The electrode sheets are rolled using special pressure rollers to apply a certain pressure, first pressing down and then rotating the rollers (e.g., ...). Figure 2 The compaction density depends on the material. Alternatively, a roller press can be used to compact the material using conventional methods. After compaction, the weight should be weighed again to confirm the weight.

[0088] 4. The lithium sheet and nickel strip tabs are bonded together using conductive adhesive (e.g., Figure 3 Nickel strip tabs are used to lead out conductivity. The conductive adhesive is an adhesive system such as epoxy resin, silicone resin, polyimide resin, phenolic resin, polyurethane, and acrylic resin, and does not contain water. The conductive filler can be powders of gold, silver, copper, aluminum, zinc, iron, and nickel, as well as graphite and some conductive compounds, but is not limited to these.

[0089] 5. Snap-on assembly: ① Use aluminum-plastic film to punch out housing B ( Figure 4 ), the diameter of the crater is b, b > a, and the crater depth HB < lithium sheet thickness; ② Place the lithium sheet with tabs, add electrolyte to the lithium sheet, place the separator, and wait for the separator to be fully wetted, the separator size c > b; ③ Use a special electrode sheet pressed with "3" rollers, and wet the surface with electrolyte; ④ Combine the outer casing A and outer casing B, and use an edge sealing machine to thermoplastic seal the two to obtain the button cell battery. Figure 5 )

[0090] 6. Testing: After assembly, let stand for 4-8 hours, apply a certain pressure using a clamp, and clamp the large face of the fastener for testing.

[0091] Example 2:

[0092] 1. Based on the battery fabricated in Example 1, a three-electrode coin cell assembly is performed using the method of embedding copper wires. This can be used to monitor the electrochemical behavior of active materials, including potential, plateau, etc., and can also be extended to other tests.

[0093] 2. Assembly of the battery: ① Use aluminum-plastic film to punch out the casing B, with a punched pit diameter of b, requiring b > a, and a punched pit depth HB < lithium sheet thickness; ② Place the lithium sheet with tabs, add electrolyte to the lithium sheet, place the separator, and wait for the separator to be fully wetted, with separator size c > b; ③ Use a special electrode sheet pressed with "3" rollers, and wet its surface with electrolyte; ④ Pre-embed a 30-60µm copper wire in the casing A, and fix the copper wire with electrolyte-resistant tape. The copper wire must not exceed the active material area. Figure 6 ⑤ Combine outer casing A and outer casing B, and use an edge sealing machine to thermo-encapsulate them to obtain the three-electrode button cell.

[0094] 3. Testing: After assembly, let stand for 4-8 hours, apply a certain pressure using a clamp, and clamp the large face of the fastener for testing.

[0095] Example 3:

[0096] 1. Furthermore, this structure can be used to make small single-cell batteries, which have the advantages of small size, low material loss, and fast manufacturing.

[0097] 2. Using the cut single-sided electrode sheet, with the positive electrode sheet size smaller than the positive electrode sheet (i.e., the electrode sheet with single-sided coating), use conductive adhesive to attach the electrode tab to the uncoated area. (Refer to...) Figure 3 .

[0098] 3. Assembly of a single-cell button cell: ① Use aluminum-plastic film to punch out casings A and B, with punching diameters a and b respectively, requiring b > a and punching depth H < electrode thickness; ② Place the electrode with tabs, drop electrolyte onto the electrode, place the separator, and wait for the separator to be fully wetted, with separator size c > b; ③ Combine casings A and B, and use an edge sealing machine to thermo-encapsulate them to obtain the small single-cell button cell battery.

[0099] In one embodiment, such as Figures 2 to 6As shown, a button cell 10 is provided, including a first housing 210, a second housing 220, a separator 410, and a second electrode 320; the first housing 210 includes a conductive layer 211 and an insulating layer 212 covering the outside of the conductive layer 211; a first mounting groove 213 is provided in the middle of the first housing 210; the insulating layer 212 has a through hole in the first mounting groove 213; the conductive layer 211 is exposed outside the insulating layer 212 through the through hole in the first mounting groove 213; the surface of the conductive layer 211 is coated with an active material layer 250 within the range of the first mounting groove 213; a first tab 510 is connected to one side of the first housing 210; the first tab 510 is connected to the conductive layer 211. One side of the second electrode 320 is connected to the second tab 520; a second mounting groove 221 is provided in the middle of the second housing 220; the edges of the first housing 210 and the second housing 220 are sealed together, and the first mounting groove 213 and the second mounting groove 221 are sealed to form a mounting cavity. The first tab 510 and the second tab 520 are at least partially exposed in the mounting cavity. The diaphragm 410 and the second electrode 320 are disposed in the mounting cavity, wherein the second electrode 320 is disposed in the second mounting groove 221, and the diaphragm 410 is disposed on the side of the second electrode 320 facing away from the second housing 220, and the diaphragm 410 isolates the active material layer 250 and the second electrode 320.

[0100] In this embodiment, the conductive layer 211 of the first housing 210 serves as the first electrode. An electrolyte is disposed between the second electrode 320 and the diaphragm 410, and between the first housing 210 and the diaphragm 410. The diaphragm isolates the conductive layer (serving as the first motor) and the second electrode 320. After thermoplastic encapsulation of the first housing 210 and the second housing 220, the first mounting groove 213 and the second mounting groove 221 are connected and their outer edges are sealed to form a mounting cavity, encapsulating the diaphragm 410, the second electrode 320, and the electrolyte within. The first housing 210 has a recessed first mounting groove 213. The insulating layer 212 is hollowed out within the first mounting groove 213 to form a through hole, allowing the conductive layer 211 to be exposed through the through hole. An active material layer 250 is disposed on the exposed surface of the conductive layer 211.

[0101] In this embodiment, the active material layer 250 is disposed on the surface of the conductive layer 211 of the first housing 210, which avoids the problem of uneven electrode thickness and detachment of the active material layer 250 caused by the active material layer 250 being coated on the electrode and rolled. This effectively avoids the problem of large fluctuations in specific capacity, making the specific capacity more stable and thus effectively improving battery performance.

[0102] In one embodiment, the first housing 210 is configured such that the conductive layer 211 comprises an aluminum layer; and / or the insulating layer 212 comprises a PE layer.

[0103] In this embodiment, the insulating layer 212 of the first housing 210 includes a PE (Polyethylene) layer, and the conductive layer 211 is a metal layer, such as an aluminum layer. In this embodiment, the first housing 210 is an aluminum-plastic film, including a first PE layer, an aluminum layer, and a second PE layer. The first PE layer and the second PE layer cover the outside of the aluminum layer. In other embodiments, the first housing 210 may also use other materials for the insulating layer 212 and the conductive layer 211, and is not limited to aluminum-plastic film.

[0104] In one embodiment, such as Figure 6 As shown, the width of the diaphragm 410 is greater than the width of the second mounting groove 221. In this embodiment, since the width of the diaphragm 410 is greater than the width of the second mounting groove 221, and since the second electrode 320 is located within the second mounting groove 221, the diaphragm 410 can sufficiently isolate the second electrode 320 and the first housing 210, which serves as the first electrode.

[0105] In one embodiment, such as Figure 3 and Figure 6 As shown, the cross-sectional shape of the first mounting groove 213 is trapezoidal. In this embodiment, the cross-sectional shape of the first mounting groove 213 in the direction perpendicular to the conductive layer 211 is trapezoidal. In this embodiment, the depth of the first mounting groove 213 gradually increases from the edge to the center, and the sidewall of the first mounting groove 213 gradually slopes towards the bottom of the first mounting groove 213 from the outside to the inside. This makes the cross-section of the first mounting groove 213 trapezoidal. Thus, for the first housing 210 that is stamped after coating with the active material layer 250, the conductive layer 211 can be gradually deformed from the outside to the inside during the stamping of the first housing 210. The waist of the trapezoid allows the depth of the first mounting groove 213 to gradually increase, avoiding large-angle (90-degree) deformation of the conductive layer 211, thereby effectively preventing the active material layer 250 on the conductive layer 211 from falling off during the stamping process.

[0106] In one embodiment, the second electrode 320 and the second tab 520 are configured such that: the second electrode 320 is a lithium sheet; and / or the second tab 520 is a nickel strip tab; and / or the second electrode 320 is bonded to the second tab 520 by conductive adhesive.

[0107] In this embodiment, the first electrode (the conductive layer of the first housing 210) and the second electrode 320 can be either positive or negative. For example, the conductive layer of the first housing 210 can be positive and the second electrode 320 can be negative. In one embodiment, the second electrode 320 is a lithium sheet. In this embodiment, the conductive layer of the first housing 210 is a positive electrode, and the second electrode 320 is a negative lithium sheet. The second electrode 320 can also be called a lithium sheet. The second tab 520 is a nickel strip tab. In this embodiment, the lithium sheet is bonded to the nickel strip tab with conductive adhesive. Specifically, the nickel strip tab is used to lead out conductivity. The conductive adhesive includes an adhesive and a conductive filler. The adhesive includes at least one of epoxy resin, silicone resin, polyimide resin, phenolic resin, polyurethane, and acrylic resin. The conductive adhesive is water-free. The conductive filler can be powder of gold, silver, copper, aluminum, zinc, iron, nickel, and / or graphite and some conductive compounds, but is not limited to these.

[0108] In one embodiment, such as Figure 6 As shown, the width of the second mounting groove 221 is greater than the width of the first mounting groove 213. This makes the area of ​​the second mounting groove 221 larger than the area of ​​the first mounting groove 213, which is beneficial for the second mounting groove 221 to better accommodate the second electrode 320.

[0109] In one embodiment, such as Figure 6 As shown, the depth of the second mounting groove 221 is less than the thickness of the second electrode 320.

[0110] In this embodiment, the depth of the second mounting groove 221 is less than the thickness of the second electrode 320. Thus, when the second electrode 320 is placed in the second mounting groove 221, the second electrode 320 protrudes at least partially onto the second mounting groove 221. Subsequently, a diaphragm 410 is placed on the second electrode 320. Since the width of the diaphragm 410 is greater than the width of the second mounting groove 221, the diaphragm 410 can effectively block the second electrode 320 and isolate the second electrode 320 from the conductive layer of the first housing 210.

[0111] In one embodiment, the through-hole is circular, and the first mounting groove 213 has a circular cross-sectional shape in the direction parallel to the conductive layer 211. In this embodiment, the circular through-hole and the first mounting groove 213 can better fit the shape of the circular diaphragm 410. In other embodiments, the through-hole can also be triangular, square, or regular polygonal, and the first mounting groove 213 can also have a triangular, square, or regular polygonal cross-sectional shape in the direction parallel to the conductive layer 211.

[0112] In one embodiment, such as Figure 7As shown, the coin cell 10 also includes a conductive wire 610. A first end of the conductive wire 610 is connected to the side of the insulating layer 212 facing the separator, and a second end of the conductive wire 610 extends to the outside of the first housing 210 and the second housing 220. In this embodiment, the conductive wire 610 serves as the third electrode of the coin cell 10, providing signal transmission to monitor the electrochemical behavior of the battery's active materials, including potential, plateau, etc. Furthermore, other tests can be extended using this conductive wire 610. In this embodiment, a conductive wire 610 is first installed on the first housing 210. The first end of the conductive wire 610 is connected to the insulating layer 212 of the first housing 210, and the second end of the conductive wire 610 extends to the outside of the first housing 210. During the encapsulation of the first housing 210 and the second housing 220, the second end of the conductive wire 610, the end of the first tab 510 furthest from the first housing 210, and the end of the second tab 520 furthest from the second electrode 320 are exposed in the mounting cavity. This allows the second end of the conductive wire 610, the end of the first tab 510 furthest from the first housing 210, and the end of the second tab 520 furthest from the second electrode 320 to extend to the outside of the first housing 210 and the second housing 220, facilitating connection to external electrical components. Thus, the battery signal can be monitored through this conductive wire 610. In one embodiment, the conductive wire 610 is a copper wire with a diameter of 30-60 μm. In this embodiment, electrolyte-resistant tape is used to fix and bond the copper wire to the insulating layer 212 of the first housing 210, preventing the copper wire from connecting with the active material layer 250. After encapsulation, a three-electrode coin cell 10 is formed. The copper wire allows for monitoring of the electrochemical behavior of the battery's active material, such as potential and plateau.

[0113] Performance parameter comparison:

[0114] This section compares the specific capacity and internal resistance of the button cells prepared in Example Groups 1 and 2 and Control Groups 1 and 2. Example Groups 1 and 2 are manufactured using the button cell structure and manufacturing method described in the above examples, while Control Groups 1 and 2 are traditional steel-cased button cells. The comparison results are shown in Tables 1 and 2.

[0115] This application changes the traditional manufacturing method of positive / negative electrode sheets for steel-cased batteries, resulting in more accurate areal density and eliminating the need for stamping. This eliminates the risk of material loss during stamping, thereby improving the accuracy of specific capacity and first-efficiency measurement, and reducing test fluctuations.

[0116] Table 1 Comparison of gram capacity between the control group and the example group.

[0117]

[0118]

[0119] As shown in Table 1, the difference (range) between the minimum and maximum capacity values ​​in the example group was significantly smaller than that in the control group, and the fluctuation of capacity was significantly smaller.

[0120] Furthermore, since traditional current collectors are not required, the active material adheres directly to the casing, and the lithium foil is led out by connecting it to nickel strip tabs using conductive adhesive, thereby reducing the battery's internal resistance. The internal resistance is tested using an internal resistance instrument or an electrochemical workstation, taking the resistance value at 1000Hz, but is not limited to this method.

[0121] Table 2 Comparison of internal resistance values ​​between the control group and the example group.

[0122]

[0123] As shown in Table 2, the mean internal resistance in the example group was significantly lower than that in the control group.

[0124] Furthermore, the coin cell structure with conductive wires described in this application makes it easier to fabricate three-electrode coin cells for monitoring potential changes of the positive or negative electrode materials during charging and discharging. Structurally, it offers better sealing than traditional steel-cased structures, thus better liquid retention. Combined with reduced internal resistance, this coin cell allows for more extensive electrical performance testing, such as cycle testing. Its short fabrication cycle also enables rapid material performance screening, broadening its application scenarios.

[0125] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0126] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for manufacturing a button cell battery, characterized in that, include: A first housing is provided, wherein the first housing includes a conductive layer and an insulating layer covering the outside of the conductive layer, a first mounting groove is provided in the middle of the first housing, a through hole is formed in the insulating layer in the first mounting groove, the conductive layer is exposed outside the insulating layer through the through hole in the first mounting groove, an active material layer is coated on the surface of the conductive layer within the range of the first mounting groove, and a first electrode tab is connected to one side of the first housing, the first electrode tab being connected to the conductive layer; A second electrode is provided, and one side of the second electrode is connected to a second electrode tab; A second housing is provided, wherein a second mounting groove is provided in the middle of the second housing; The second electrode is installed into the second mounting groove of the second housing, electrolyte is added into the second mounting groove, and then a diaphragm is placed in, wherein the width of the diaphragm is greater than the width of the second mounting groove. Add electrolyte to the first mounting tank; The edges of the first housing and the second housing are sealed, and the first mounting groove and the second mounting groove are sealed to form a mounting cavity, thus obtaining a button cell battery.

2. The method according to claim 1, characterized in that, The step of encapsulating the edges of the first housing and the second housing, and sealing the first mounting groove and the second mounting groove to form a mounting cavity to obtain a button cell includes: Align the first mounting groove of the first housing with the second mounting groove, use the diaphragm to isolate the second electrode and the active material layer, encapsulate the edges of the first housing and the second housing, and seal the first mounting groove and the second mounting groove to form a mounting cavity, thus obtaining a button cell.

3. The method according to claim 1, characterized in that, Prior to the step of providing the second housing, the following also includes: Provide a second prototype shell; The second prototype shell is stamped to form a second mounting groove in the middle of the second prototype shell, thereby obtaining the second shell, wherein the width of the second mounting groove is greater than the width of the first mounting groove.

4. The method according to claim 1, characterized in that, Prior to the step of providing the first housing, the following also includes: A first prototype housing is provided, wherein the first prototype housing includes a conductive layer and an insulating layer covering the outside of the conductive layer, the insulating layer has a through hole in the middle of the first prototype housing, and the conductive layer is exposed to the insulating layer through the through hole; The first prototype shell is stamped to form a first mounting groove in the middle of the first prototype shell, thereby obtaining the first shell, wherein the range of the first mounting groove coincides with the range of the through hole; An active substance slurry is coated on the surface of the conductive layer within the first mounting groove. After the active substance slurry is cured, an active substance layer is formed on the surface of the conductive layer.

5. The method according to claim 1, characterized in that, Prior to the step of providing the first housing, the following also includes: A first prototype housing is provided, wherein the first prototype housing includes a conductive layer and an insulating layer covering the outside of the conductive layer, the insulating layer has a through hole in the middle of the first prototype housing, and the conductive layer is exposed to the insulating layer through the through hole; An active substance slurry is coated on the surface of the conductive layer exposed within the through-hole area. After the active substance slurry is cured, an active substance layer is formed on the surface of the conductive layer. The first prototype housing is stamped to form a first mounting groove in the middle of the first prototype housing, thereby obtaining the first housing, wherein the range of the first mounting groove coincides with the range of the through hole.

6. The method according to claim 1, characterized in that, The active material slurry forming the active material layer includes an active material, a conductive agent, a binder, and a dispersant, and the mass ratio of the active material, the conductive agent, the binder, and the dispersant is 95.0:2.0:1.5:1.

5.

7. The method according to claim 1, characterized in that, The conductive layer includes an aluminum layer, and the insulating layer includes a PE layer.

8. The method according to claim 1, characterized in that, The second electrode is a lithium sheet, and the second tab is a nickel strip tab. The lithium sheet is bonded to the nickel strip tab with conductive adhesive.

9. The method according to any one of claims 1-8, characterized in that, The step of encapsulating the edges of the first housing and the second housing, and sealing the first mounting groove and the second mounting groove to form a mounting cavity to obtain a button cell includes: A conductive wire is installed on the side of the first housing facing the diaphragm, with a first end of the conductive wire connected to the insulating layer and a second end of the conductive wire extending to the outside of the first housing; Align the first mounting groove of the first housing with the second mounting groove, use the diaphragm to isolate the second electrode and the active material layer, encapsulate the edges of the first housing and the second housing, seal the first mounting groove and the second mounting groove to form a mounting cavity, and expose at least part of the conductive wire, the first electrode tab and the second electrode tab in the mounting cavity to obtain a button cell.

10. A button cell battery, characterized in that, include: First housing, second housing, diaphragm, and second electrode; The first housing includes a conductive layer and an insulating layer covering the outside of the conductive layer. A first mounting groove is provided in the middle of the first housing. The insulating layer has a through hole in the first mounting groove. The conductive layer is exposed outside the insulating layer through the through hole in the first mounting groove. An active material layer is coated on the surface of the conductive layer within the range of the first mounting groove. A first electrode is connected to one side of the first housing. The first electrode is connected to the conductive layer. One side of the second electrode plate is connected to the second electrode tab; A second mounting groove is provided in the middle of the second housing; The edges of the first housing and the second housing are sealed together, the first mounting groove and the second mounting groove are sealed to form a mounting cavity, the first electrode tab and the second electrode tab are at least partially exposed in the mounting cavity, the diaphragm and the second electrode are disposed in the mounting cavity, wherein the second electrode is disposed in the second mounting groove, the diaphragm is disposed on the side of the second electrode facing away from the second housing, and the diaphragm isolates the active material layer and the second electrode.

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