Button cell and method of manufacturing the same

Abstract

The application discloses a preparation method of a button cell, and the preparation method comprises the following steps: S1, providing a battery roll core, wherein the battery roll core comprises a positive electrode lug and a negative electrode lug; S2, providing a shell assembly, wherein the shell assembly comprises a positive electrode shell and a negative electrode shell; S3, providing a first metal pressing sheet, wherein the first metal pressing sheet is used for pressing and fixing the negative electrode lug on the inner surface of the negative electrode shell, and then the battery roll core is placed into the negative electrode shell; S4, providing a second metal pressing sheet, wherein the second metal pressing sheet is used for pressing and fixing the positive electrode lug on the inner surface of the positive electrode shell; and S5, injecting liquid into the negative electrode shell, packaging the positive electrode shell and the negative electrode shell, and obtaining the button cell. In the preparation method, the lug and the shell assembly are connected without welding, and the battery defects caused by the welding process are reduced.

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] Button batteries, also known as coin cells, are characterized by their small size and stable discharge, with dimensions measured in millimeters. The structure of a button battery includes a casing for encapsulation and an internal cell, with the cell and casing connected by tabs. Currently, the tabs of button batteries are typically connected to the cell or casing by welding. Because the tabs are thin, over-welding can easily cause breakage during the welding process. Furthermore, the cell expands during charge-discharge cycles, making the weld points between the tabs and the casing or cell susceptible to tensile stress and breakage, leading to battery failure. Summary of the Invention

[0003] The primary objective of this invention is to overcome the shortcomings of the prior art and provide a method for manufacturing a button cell battery in which the tabs of the button cell battery are connected to the casing assembly without welding, thereby reducing battery defects caused by welding processes.

[0004] A secondary objective of this invention is to provide a button cell prepared by the above-described preparation method.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for preparing a button cell battery includes the following steps:

[0007] S1: Provide a battery core, the battery core including a positive electrode tab and a negative electrode tab;

[0008] S2: Provide a housing assembly, the housing assembly including a positive electrode housing and a negative electrode housing;

[0009] S3: Provide a first metal sheet, which presses and fixes the negative electrode tab on the inner surface of the negative electrode housing, and then puts the battery core into the negative electrode housing;

[0010] S4: Provide a second metal plate, which presses and fixes the positive electrode tab to the inner surface of the positive electrode housing;

[0011] S5: Inject liquid into the negative electrode casing, and encapsulate the positive electrode casing and the negative electrode casing to obtain the button cell.

[0012] In one embodiment, the first metal plate is cross-connected to the negative electrode tab, and the two ends of the first metal plate are welded to the inner surface of the negative electrode housing.

[0013] In one embodiment, the welding of the two ends of the first metal plate is performed by either internal welding or external welding.

[0014] In one embodiment, the first metal plate is pre-positioned with the negative electrode tab before welding.

[0015] In one embodiment, the order of steps S1 and S2 is not limited, nor is the order of steps S3 and S4.

[0016] In one embodiment, step S1, providing the battery core includes the following steps:

[0017] S100: A positive electrode material is coated on a positive electrode current collector, and the positive electrode sheet is obtained by roll pressing and slitting. One end of the positive electrode sheet has a first empty foil area that is not coated with the positive electrode material.

[0018] S200: A negative electrode material is coated on a negative electrode current collector, and the negative electrode sheet is obtained by roll pressing and slitting. One end of the negative electrode sheet has a second empty foil area that is not coated with the negative electrode material.

[0019] S300: Provide a separator, and stack the positive electrode sheet, the separator and the negative electrode sheet in sequence and perform a winding operation to obtain a battery core;

[0020] S400: Fold the first empty foil area and the second empty foil area respectively, so that the first empty foil area and the second empty foil area are drawn out from the battery core to form a positive electrode tab and a negative electrode tab respectively.

[0021] In one embodiment, during step S300, when the foils are stacked sequentially, the first empty foil area and the second empty foil area are disposed at the same end or at opposite ends.

[0022] In one embodiment, the second empty foil region undergoes surface strengthening treatment.

[0023] In one embodiment, the surface strengthening treatment is to plate the first empty foil area with nickel, silver, or tin.

[0024] In one embodiment, the surface strengthening treatment of the second empty foil area is performed before or after coating.

[0025] The present invention also provides a button battery, which is prepared by the above-described preparation method and has the characteristics of low production defect rate and long service life.

[0026] Compared with the prior art, the present invention has at least the following advantages:

[0027] The button battery manufacturing method provided by this invention does not use the traditional direct welding of positive / negative electrode tabs to the outer casing assembly. Instead, it uses a first / second metal pressure plate to press the positive / negative electrode tabs against the inside of the casing. This achieves a non-welded connection between the positive / negative electrode tabs and the casing assembly, avoiding production defects such as incomplete welding or over-welding caused by welding the positive / negative electrode tabs. At the same time, the positive / negative electrode tabs are connected to the casing assembly through the pressing action of the metal pressure plate. There is a movement margin between the positive / negative electrode tabs and the casing assembly. When the button battery expands in volume, even if a tensile force is applied to the positive / negative electrode tabs, it is not easy for them to break, thus improving the service life of the button battery. Attached Figure Description

[0028] Figure 1 This is a flowchart illustrating the steps of a button battery preparation method according to an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram of the structure of a button battery according to an embodiment of the present invention;

[0030] Figure 3 This is a cross-sectional structural diagram of a button battery according to an embodiment of the present invention.

[0031] Figure 4 This is a schematic diagram of the negative electrode current collector of a button battery according to an embodiment of the present invention.

[0032] Figure 5 This is a schematic diagram of the negative electrode sheet according to one embodiment of the present invention. Detailed Implementation

[0033] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0034] Please see Figures 1 to 3 A method for preparing a button cell battery includes the following steps:

[0035] S1: Provides a battery core 100, which includes a positive electrode tab 110 and a negative electrode tab 120;

[0036] S2: Provide housing assembly 200, housing assembly 200 including positive electrode housing 210 and negative electrode housing 220;

[0037] S3: Provide a first metal plate 300, which presses and fixes the negative electrode tab 120 to the inner surface of the negative electrode housing 220, and then puts the battery core 100 into the negative electrode housing 220.

[0038] S4: Provide a second metal plate 400, which presses and fixes the positive electrode tab 110 to the inner surface of the positive electrode housing 210;

[0039] S5: Inject liquid into the negative electrode casing 220, and encapsulate the positive electrode casing 210 and the negative electrode casing 220 to obtain the button cell 10.

[0040] It should be noted that in existing button batteries, the tabs are generally connected to the casing assembly 200 by welding. Due to the small thickness of the tabs in button batteries, incomplete or over-welded connections are easily caused during welding, leading to manufacturing defects. Based on the shortcomings of existing technology, this invention provides a new method for manufacturing button batteries. The positive / negative tabs 120 are pressed against the surface of the casing assembly 200 by first / second metal plates 400, thus connecting the positive / negative tabs 120 to the casing assembly 200 without directly welding the tabs 120. This avoids manufacturing defects caused by welding. Furthermore, the battery core 100 will undergo a certain volume expansion during the liquid injection process and charge-discharge cycles. During the volume expansion process, the positive / negative tabs are subjected to radial tensile force. In traditional welding processes, the welding points of the positive / negative tabs 120 are prone to breakage under tensile force. However, in the improved preparation method of this invention, there is a movement margin between the positive / negative tabs 120 and the first / second metal pressing sheet 400 and the housing assembly 200. Therefore, the positive / negative tabs 120 are not prone to breakage when the battery core 100 expands in volume, which further reduces the defect rate of button cell production and improves the service life of button cell.

[0041] It should be noted that the order of steps S1 and S2 is not limited, nor is the order of steps S3 and S4.

[0042] It should be noted that the housing assembly 200 also includes a sealing ring 230. The sealing ring 230 is fitted onto the outer wall of the negative electrode housing 220 before encapsulation. When the positive electrode housing 210 is fastened, the sealing ring 230 is positioned between the negative electrode housing 220 and the positive electrode housing 210, serving to seal and prevent short circuit between the positive and negative electrodes.

[0043] Please see Figure 2 and Figure 3In one embodiment, the first metal plate 300 is cross-connected with the negative electrode tab 120, and the two ends of the first metal plate 300 are welded to the inner surface of the negative electrode housing 220. Similarly, the second metal plate 400 is cross-connected with the positive electrode tab 110, and the two ends of the second metal plate 400 are welded to the inner surface of the positive electrode housing 210.

[0044] It should be noted that the two ends of the first metal pressure plate 300 are fixed to the inner surface of the negative electrode housing 220 by welding, and the first metal pressure plate 300 is cross-connected with the negative electrode tab 120. In this way, the first metal pressure plate 300 presses the negative electrode tab 120 onto the negative electrode housing 220, realizing a non-welded connection between the negative electrode tab 120 and the negative electrode housing 220. Furthermore, in order to improve the connection stability of the negative electrode tab 120, the first metal pressure plate 300 and the negative electrode tab 120 are cross-connected at 90°, and the welding points 310 at both ends of the first metal pressure plate 300 are symmetrically arranged on both sides of the negative electrode tab 120 along the width direction. Furthermore, the negative electrode housing 220 is provided with an arc-shaped protrusion on the surface of the connection between the negative electrode housing 220 and the negative electrode tab 120 to enhance the conductivity stability of the negative electrode housing 220 and the negative electrode tab 120. The second metal pressure plate 400 is connected to the positive electrode tab 110 in the same way.

[0045] Optionally, the first / second metal pressure plate 400 is made of metal steel sheet. Metal steel sheet has good toughness, is not easy to break, and is corrosion resistant. When used as the first / second metal pressure plate 400, it is not easy to deform during the welding process and can maintain good holding force on the positive / negative electrode tabs 120. At the same time, metal steel sheet has good anti-corrosion effect on electrolyte.

[0046] Furthermore, the welding of the two ends of the first / second metal plate 400 can be either internal welding or external welding.

[0047] It should be noted that when internal welding is used, the positive / negative electrode tabs 120 are placed on the inner surface of the corresponding positive / negative electrode shells, and then the first / second metal plates 400 are cross-pressed on the positive / negative electrode tabs 120. Then, the first / second metal plates 400 are welded to the inner surface of the positive / negative electrode shells by welding methods such as resistance welding and laser welding, thus connecting the positive / negative electrode tabs 120 to the positive / negative electrode shells.

[0048] When using external welding, the positive / negative electrode tabs 120 are placed on the inner surface of the corresponding positive / negative electrode shells, and then the first / second metal plates 400 are cross-pressed on top of the positive / negative electrode tabs 120. Then, liquid is injected and encapsulated. Then, the two ends of the first / second metal plates 400 are welded to the outer surface of the positive / negative electrode shells by resistance welding, laser welding or other methods.

[0049] Furthermore, the first metal plate 300 is pre-positioned with the negative electrode tab 120 before welding; optionally, the second metal plate 400 is pre-positioned with the positive electrode tab 110 before welding.

[0050] It should be noted that, in order to improve the ease of operation and the connection stability of the negative electrode tab 120, the first metal plate 300 and the negative electrode tab 120 can be cross-positioned before welding, and then placed into the negative electrode shell for welding. For example, the first metal plate 300 and the negative electrode tab 120 can be positioned by adhesive tape.

[0051] Please see Figure 4 and Figure 5 To achieve a solder-free process for the positive and negative tabs throughout the entire manufacturing process of button batteries, the manufacturing process of battery core 100 includes the following steps:

[0052] S100: A positive electrode material is coated on a positive electrode current collector, and the positive electrode sheet is obtained by roll pressing and slitting. One end of the positive electrode sheet has a first empty foil area that is not coated with positive electrode material.

[0053] S200: A negative electrode material is coated on the negative electrode current collector, and the negative electrode sheet is obtained by roll pressing and slitting. One end of the negative electrode sheet has a second empty foil area 140 that is not coated with negative electrode material.

[0054] S300: Provides a separator, and stacks the positive electrode, separator and negative electrode 510 in sequence and performs a winding operation to obtain the battery core 100.

[0055] S400: The first empty foil area and the second empty foil area 140 are folded respectively, so that the first empty foil area and the second empty foil area 140 are drawn out from the battery core 100 to form the positive electrode tab 110 and the negative electrode tab 120 respectively.

[0056] It should be noted that the positive and negative current collectors are conductive metal foils. During coating, a first empty foil area and a second empty foil area 140 are reserved respectively. The first and second empty foil areas 140 are directly bent and led out as the positive electrode tab 110 and the negative electrode tab 120, respectively, without the need for a welding process between the tabs and the current collector, thus achieving a welding-free process for the tabs and further reducing the defect rate of button batteries. Optionally, the positive current collector is made of aluminum foil, and the negative current collector is made of copper foil.

[0057] Furthermore, in step S300, during the sequential stacking, the first empty foil area and the second empty foil area 140 are located at the same end or at opposite ends.

[0058] It should be noted that when the first empty foil area and the second empty foil area 140 are at the same end, after the winding operation is completed, the first empty foil area and the second empty foil area 140 are located on the outer periphery of the battery core 100. After folding, the positive electrode tab 110 and the negative electrode tab 120 are led out from the outer periphery of the battery core 100. When the first empty foil area and the second empty foil area 140 are respectively located at both ends, after the winding operation is completed, the first empty foil area and the second empty foil area 140 are folded, and the positive electrode tab 110 and the negative electrode tab 120 are led out from the center and the outer periphery of the battery core 100, respectively. At this time, the short circuit of the positive electrode tab 110 and the negative electrode tab 120 can be avoided.

[0059] Furthermore, the second empty foil region 140 undergoes surface strengthening treatment, and optionally, the first empty foil region also undergoes surface strengthening treatment.

[0060] It should be noted that since the negative current collector is usually made of copper, the copper foil is prone to oxidation during use, which reduces its conductivity and can even lead to complete failure. The second empty foil area 140 is folded over and used as the negative electrode tab 120. Therefore, surface strengthening treatment of the second empty foil area 140 can solve the problem of poor contact caused by copper foil oxidation. Furthermore, since the negative current collector is a single layer of copper foil, the reserved second empty foil area is folded over to lead out the negative electrode tab 120. At this time, the strength of the negative electrode tab 120 is low and there is a risk of breakage. Surface treatment can effectively increase its strength and prevent breakage. At the same time, the increased strength of the negative electrode tab 120 allows it to fit more tightly with the negative electrode shell 220, making the product more reliable.

[0061] In one embodiment, the surface strengthening treatment is to perform nickel plating, silver plating, or tin plating on the second empty foil area 140. Optionally, the first copper foil area is simultaneously subjected to nickel plating, silver plating, or tin plating.

[0062] Furthermore, the surface strengthening treatment of the second empty foil area 140 is performed before or after coating.

[0063] Please see Figure 4 It should be noted that the negative current collector includes a coating area 130 and a second empty foil area 140. Before coating, surface strengthening treatment is performed, that is, according to the product size, a positioning metal plating layer is first performed on the second empty foil area 140, and then positioning coating is performed on the coating area 130. After coating, surface strengthening treatment is performed, that is, according to the product size, positioning coating is first performed on the coating area 130, and then after coating is completed, a metal plating layer is performed on the second empty foil area 132.

[0064] Please see Figure 5 In step S500, the folding angle of the first empty foil area and the second empty foil area 140 is 90°, which makes it easier to install the positive electrode tab 110 and the negative electrode tab 120 with the housing assembly 200.

[0065] In another embodiment, the folding operation of the first empty foil area and the second empty foil area 140 is performed before the winding operation. That is, the folding operation can be performed either before or after the winding operation, and the order does not affect the final lead-out of the positive and negative electrode tabs.

[0066] The present invention also provides a button battery 10 prepared by the above preparation method. The positive electrode tab 110 and the negative electrode tab 120 of the button battery 10 are connected to the housing assembly 200 in a solderless manner, which greatly reduces the defects of finished products caused by poor welding, and also reduces the battery failure caused by the tab breakage due to the volume expansion of the battery core 100.

[0067] The embodiments described above are merely illustrative of several implementations of the present invention, 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 the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing a button cell battery, characterized in that, Includes the following steps: S1: Provide a battery core, the battery core including a positive electrode tab and a negative electrode tab; S2: Provide a housing assembly, the housing assembly including a positive electrode housing and a negative electrode housing; S3: Provide a first metal sheet, which presses and fixes the negative electrode tab on the inner surface of the negative electrode housing, and then puts the battery core into the negative electrode housing; S4: Provide a second metal plate, which presses and fixes the positive electrode tab to the inner surface of the positive electrode housing; S5: Inject liquid into the negative electrode casing, and encapsulate the positive electrode casing and the negative electrode casing to obtain the button cell; The first metal plate is cross-connected to the negative electrode tab, and both ends of the first metal plate are welded to the inner surface of the negative electrode housing; The second metal plate is cross-connected to the positive electrode tab, and both ends of the second metal plate are welded to the inner surface of the positive electrode shell; The positive and negative electrode tabs have a certain amount of movement between the metal plate and the housing assembly.

2. The method for preparing a button cell according to claim 1, characterized in that, The welding of the two ends of the first metal plate can be either internal or external welding.

3. The method for preparing a button cell according to claim 1, characterized in that, Before welding, the first metal plate is pre-positioned with the negative electrode tab.

4. The method for preparing a button cell according to claim 1, characterized in that, In step S1, providing the battery core includes the following steps: S100: A positive electrode material is coated on a positive electrode current collector, and the positive electrode sheet is obtained by roll pressing and slitting. One end of the positive electrode sheet has a first empty foil area that is not coated with the positive electrode material. S200: A negative electrode material is coated on a negative electrode current collector, and the negative electrode sheet is obtained by roll pressing and slitting. One end of the negative electrode sheet has a second empty foil area that is not coated with the negative electrode material. S300: Provide a separator, and stack the positive electrode sheet, the separator and the negative electrode sheet in sequence and perform a winding operation to obtain a battery core; S400: Fold the first empty foil area and the second empty foil area respectively, so that the first empty foil area and the second empty foil area are drawn out from the battery core to form a positive electrode tab and a negative electrode tab respectively.

5. The method for preparing a button cell according to claim 4, characterized in that, In step S300, during the sequential stacking, the first empty foil area and the second empty foil area are either located at the same end or located at opposite ends.

6. The method for preparing a button cell according to claim 4, characterized in that, The second empty foil area undergoes surface strengthening treatment.

7. The method for preparing a button cell according to claim 6, characterized in that, The surface strengthening treatment involves plating the second empty foil area with nickel, silver, or tin.

8. The method for preparing a button cell according to claim 6, characterized in that, The surface strengthening treatment of the second empty foil area is performed before or after coating.

9. A button battery, characterized in that, The button cell battery is prepared according to any one of claims 1 to 8.

Images