Battery cell structure, button cell and method for preparing button cell

Abstract

The present invention relates to a battery cell structure, a button cell and a method for preparing a button cell. The battery cell structure comprises a first pole piece and a second pole piece, wherein the first pole piece and the second pole piece have opposite polarities, and at least one of the first pole piece and the second pole piece comprises a current collector region and an empty foil region, wherein the empty foil region is located at the edge of the current collector region and can extend along the length direction of the pole piece, and the empty foil region is configured to be able to form a full pole ear by bending, and the width of the empty foil region ranges from 2 mm to 4 mm. In this way, the design of leading out the full pole ear by bending the empty foil region can eliminate the influence of the angle between the other pole ear, so that the welded welded parts in the opposite direction of the winding direction can better offset the current sound generated in the process of winding the battery cell structure, so that the battery with the battery cell structure will not generate current sound in the application product, significantly improving the sound quality performance of the product, reducing the background noise interference, and thus enhancing the user experience.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and more specifically, to a battery cell structure, a button cell and a method for preparing the button cell. Background Art

[0002] Button batteries are small energy storage devices widely used in various electronic products. The structural feature is that the positive and negative tabs are wound around the outside of the winding core and lead out at a certain angle. This design is compact and efficient, and can meet the strict requirements of electronic products for battery space utilization.

[0003] However, in actual applications, this structural battery has a common problem, that is, when the battery is attached near the audio output components such as the product speaker, the coil effect formed by the winding core winding the positive and negative electrodes will generate current sound, which will cause background noise. Background noise will not only affect the sound quality of the product and reduce the user experience, but may also cover up the audio signal of the product itself, causing signal distortion or interference.

[0004] Therefore, reducing the background noise problem of button batteries is of great significance to improving the overall performance of electronic products and user satisfaction. Summary of the invention

[0005] An object of the present invention is to provide a new technical solution for a battery cell structure, a button battery and a method for preparing a button battery.

[0006] According to a first aspect of the present invention, there is provided a battery cell structure, the battery cell structure comprising:

[0007] A first pole piece and a second pole piece, wherein the polarities of the first pole piece and the second pole piece are opposite, and at least one of the first pole piece and the second pole piece comprises a current collector area and a hollow foil area, wherein the hollow foil area is located at the edge of the current collector area and can extend along the length direction of the pole piece, and the hollow foil area is configured to form a full pole ear by bending, and the width of the hollow foil area ranges from 2 mm to 4 mm.

[0008] Optionally, a diaphragm is further included, and the diaphragm is arranged between the first pole piece and the second pole piece. Along the width direction of the battery core structure, the top of the empty foil area exceeds the top of the diaphragm.

[0009] Optionally, the top of the empty foil area exceeds the top of the diaphragm by 1.5 mm to 3.5 mm.

[0010] Optionally, the first pole sheet is a positive pole sheet, the second pole sheet is a negative pole sheet, the negative pole sheet includes a second current collector area and a second empty foil area, the second empty foil area is located at the edge of the second current collector area and can extend along the length direction of the negative pole sheet, and the second empty foil area is configured to form a negative full pole ear by bending.

[0011] Optionally, the positive electrode plate includes a first current collector region and a positive electrode tab, and the positive electrode tab is connected to the first current collector region;

[0012] Alternatively, the positive electrode plate includes a first current collector area and a first empty foil area, wherein the first empty foil area is located at the edge of the first current collector area and can extend along the length direction of the positive electrode plate, and the first empty foil area is configured to form a positive electrode full tab by bending.

[0013] Optionally, the empty foil area includes a first area, a second area and a third area, the third area is bent and connected between the first area and the second area, and at least one of the first area, the second area and the third area can extend along the length direction of the pole piece and can be bent to form a full pole ear.

[0014] According to a second aspect of the present invention, a button battery is provided, comprising a shell and the battery cell structure according to the first aspect, wherein the battery cell structure is located in the shell, and the full tab is welded to the shell.

[0015] According to a third aspect of the present invention, there is provided a method for preparing a button battery having the battery cell structure according to the first aspect, comprising:

[0016] Obtain the positive electrode;

[0017] Obtain a negative electrode sheet, wherein the negative electrode sheet comprises a second current collector region and a second empty foil region, wherein the second empty foil region is located at an edge of the second current collector region and can extend along a length direction of the negative electrode sheet;

[0018] Obtaining a separator, and stacking and winding the positive electrode sheet, the separator and the negative electrode sheet to obtain a battery cell structure;

[0019] Bending the second empty foil area to form a negative electrode full tab;

[0020] The obtained battery core structure is assembled in a housing to form a button battery.

[0021] Optionally, the step of obtaining a negative electrode sheet, wherein the negative electrode sheet comprises a second current collector region and a second empty foil region, wherein the second empty foil region is located at an edge of the second current collector region and can extend along the length direction of the negative electrode sheet, comprises:

[0022] coating the negative electrode active material;

[0023] Part of the negative electrode active material is removed to form the second empty foil area, the remaining negative electrode active material forms the second current collector area, and the width of the second empty foil area ranges from 2 mm to 4 mm.

[0024] Optionally, removing part of the negative electrode active material and forming the second empty foil area comprises:

[0025] Use alcohol wiping or laser removal to remove part of the negative electrode active material.

[0026] Optionally, after removing part of the negative electrode active material and forming the second empty foil area, the method further includes:

[0027] Rolling the negative electrode sheet;

[0028] Cutting the negative electrode sheet;

[0029] The cutting position is located at the boundary between the second empty foil area and the second current collector area.

[0030] Optionally, the positive electrode sheet, the separator and the negative electrode sheet are stacked and wound to obtain a battery cell structure, comprising:

[0031] The second empty foil area and the positive electrode tab of the positive electrode sheet are respectively placed at two ends of the battery structure, and the top of the second empty foil area exceeds the top of the diaphragm along the width direction of the battery structure.

[0032] Optionally, assembling the obtained battery cell structure in a housing to form a button battery comprises:

[0033] Welding the negative electrode full tab to one end of the shell;

[0034] Fill with liquid and seal;

[0035] The positive electrode tab of the positive electrode sheet is welded to the other end of the shell.

[0036] A technical effect of the present invention is:

[0037] The battery cell structure includes a first pole piece and a second pole piece, the first pole piece and the second pole piece have opposite polarities, at least one of the first pole piece and the second pole piece includes a current collector area and an empty foil area, the empty foil area is located at the edge of the current collector area and can extend along the length direction of the pole piece, the empty foil area is configured to be able to form a full pole ear after bending, and the width of the empty foil area ranges from 2 mm to 4 mm. In this way, the design of the full pole ear can be led out by bending the empty foil area, and the influence of the angle between the other pole ear can be eliminated, so that the welded parts in the opposite direction of the winding direction can better offset the current sound generated in the process of winding the battery cell structure, so that the battery with the battery cell structure will not generate current sound in the application product, significantly improving the sound quality performance of the product, reducing the background noise interference, and thus enhancing the user experience.

[0038] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings, which constitute a part of the specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.

[0040] Figure 1 This is one of the cut schematic diagrams of the second pole piece in one embodiment of the present application.

[0041] Figure 2 This is the second cutting schematic diagram of the second pole piece in an embodiment of the present application.

[0042] Figure 3 It is a schematic diagram of the structure of the second pole piece in one embodiment of the present application.

[0043] Figure 4 It is one of the schematic diagrams of the battery cell structure in one embodiment of the present application.

[0044] Figure 5 This is the second schematic diagram of the battery cell structure in one embodiment of the present application.

[0045] Figure 6 This is the third schematic diagram of the battery cell structure in one embodiment of the present application.

[0046] Description of reference numerals:

[0047] 1. First pole piece; 11. Positive pole ear; 2. Second pole piece; 21. Second current collector region; 22. Second empty foil region; 221. First region; 222. Second region; 223. Third region; 3. Diaphragm. DETAILED DESCRIPTION

[0048] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0049] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0050] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0051] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0052] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0053] According to one embodiment of the present application, a battery cell structure is provided, such as Figure 1-Figure 6 As shown, the battery cell structure includes:

[0054] A first pole piece 1 and a second pole piece 2, wherein the first pole piece 1 and the second pole piece 2 have opposite polarities, and at least one of the first pole piece 1 and the second pole piece 2 comprises a current collector area and an empty foil area, wherein the empty foil area is located at the edge of the current collector area and can extend along the length direction of the pole piece, and the empty foil area is configured to form a full pole ear by bending, and the width of the empty foil area ranges from 2 mm to 4 mm.

[0055] Specifically, one of the first pole piece 1 and the second pole piece 2 is a positive pole piece, and the other of the first pole piece 1 and the second pole piece 2 is a negative pole piece. Both of them include a current collector region, on which corresponding active materials are coated for storing and releasing electrical energy.

[0056] like Figures 1 to 3 As shown, the second pole piece 2 may include a second current collector area 21 and a second empty foil area 22, and the second current collector area 21 is coated with a corresponding active material for storing and releasing electrical energy. The second empty foil area 22 may be an area formed by removing the active material, that is, the active material is not coated. The second empty foil area 22 is located at the edge of the second current collector area 21, and the second empty foil area 22 can at least surround the length side of the second current collector area 21, so as to form a full pole ear after bending.

[0057] In another embodiment, the first pole piece 1 may also include a first current collector area and a first empty foil area, and the first current collector area is coated with a corresponding active material for storing and releasing electrical energy. The first empty foil area may be an area formed by removing the active material, that is, the active material is not coated. The first empty foil area is located at the edge of the first current collector area, and the first empty foil area can at least surround the length side of the first current collector area, so as to form a full pole ear after bending.

[0058] In another embodiment, the first pole piece 1 and the second pole piece 2 may be provided to include a current collector area and an empty foil area, respectively. The empty foil area is located at the edge of the current collector area and can extend along the length direction of the pole piece, that is, the winding direction of the battery cell structure. The empty foil area is configured to be able to form a full pole ear after bending. That is, the pole ears of the battery cell structure are full positive pole ears and full negative pole ears. There is no need to set up additional pole ears, and the processing technology can also be simplified. Such a design can further improve the current conduction efficiency of the battery cell structure, especially in high-rate charge and discharge scenarios, and can significantly reduce the internal resistance and heat generation of the battery with the battery cell structure, thereby improving safety.

[0059] Among them, the full-ear design greatly reduces the length of the current transmission path inside the pole piece, reduces the internal resistance, and thus improves the charging and discharging efficiency and power performance of the battery with a cell structure. At the same time, due to the increase in the direct contact area between the full-ear and the collector area, the current distribution is more uniform, avoiding the problems of local overheating and overreaction, which helps to extend the service life of the battery.

[0060] Furthermore, the width of the empty foil area is set to be in the range of 2 mm to 4 mm, which can facilitate the bending process while ensuring the balance between the mechanical strength and current conduction performance of the formed full tab. Furthermore, the stability of the battery cell structure during use can be ensured, and the loss of battery capacity can be avoided, thereby ensuring the energy density of the battery with the battery cell structure.

[0061] Among them, by bending the empty foil area toward the center hole of the winding core to lead out the full pole ear, there is no need to weld the pole ear, thus avoiding the risk of pole piece breakage caused by the welding process, which helps to improve the reliability of the battery with the cell structure. In addition, the setting of the empty foil area can also reduce the exposure of active materials at the edge of the pole piece, reduce the risk of short circuit caused by mechanical damage or foreign matter intrusion, and thus improve the safety of the cell structure.

[0062] In addition, in the traditional steel shell button wound battery production process, the positive and negative pole ears are led out by winding on the outside of the winding core and forming a certain angle. This structure is easy to produce current sound due to the coil effect when the battery is attached to the audio output components such as the product speaker, causing the background noise phenomenon. The present invention uses the design of bending the empty foil area to lead out the full pole ear, which can eliminate the influence of the angle between the other pole ear, so that the welded parts in the opposite direction of the winding direction can better offset the current sound generated in the process of winding the battery cell structure, so that the battery with the battery cell structure will not produce current sound in the application product, which significantly improves the sound quality performance of the product, reduces the background noise interference, and thus enhances the user experience.

[0063] Among them, the traditional method also requires strict control of the angle and direction of the welded parts and the winding core ears to ensure welding quality and battery performance. This process is not only complicated and cumbersome, but also prone to welding defects or performance degradation due to improper operation. The present invention simplifies the welding process of the battery by bending the empty foil area to lead out the full ear design. Because the full ear structure makes the connection between the pole piece and the welded parts more direct and stable, there is no need to strictly control the angle and direction of the welded parts and the winding core ears, thereby improving welding efficiency and reducing production costs and process complexity.

[0064] Optionally, a diaphragm 3 is further included, and the diaphragm 3 is arranged between the first pole piece 1 and the second pole piece 2 , and along the width direction of the battery core structure, the top of the empty foil area exceeds the top of the diaphragm 3 .

[0065] like Figure 5 As shown, the diaphragm 3, as a key component in the battery cell structure, effectively isolates the first pole piece 1 and the second pole piece 2, prevents the occurrence of short circuit, and improves the safety of the battery cell structure. In particular, the top of the empty foil area is arranged to exceed the top of the diaphragm 3 along the width direction or the height direction of the battery cell structure, so that a complete and reliable full pole ear can be formed after the empty foil area is bent, and the potential risks caused by the contact between the edge of the diaphragm 3 and the full pole ear during processing or use, such as scratches, breakage, etc., are avoided, thereby enhancing the stability of the battery cell structure.

[0066] Optionally, the top of the empty foil area exceeds the top of the diaphragm 3 by 1.5 mm to 3.5 mm, which can ensure that a complete and reliable full pole ear is formed after bending the empty foil area while avoiding bending abnormalities caused by excessive width of the empty foil area.

[0067] Optionally, the first pole sheet 1 is a positive pole sheet, the second pole sheet 2 is a negative pole sheet, the negative pole sheet includes a second current collector area 21 and a second empty foil area 22, the second empty foil area 22 is located at the edge of the second current collector area 21 and can extend along the length direction of the negative pole sheet, and the second empty foil area 22 is configured to form a negative full pole ear by bending.

[0068] like Figures 1 to 3 As shown, the negative electrode sheet may include a second current collector area 21 and a second empty foil area 22, and the second current collector area 21 is coated with a negative electrode active material for storing and releasing electrical energy. The second empty foil area 22 may be an area formed by removing the negative electrode active material, that is, the negative electrode active material is not coated. The second empty foil area 22 is located at the edge of the second current collector area 21, and the second empty foil area 22 can at least surround the length side of the second current collector area 21, so as to form a negative electrode full pole ear after bending.

[0069] Optionally, the positive electrode plate includes a first current collector region and a positive electrode tab 11, and the positive electrode tab 11 is connected to the first current collector region;

[0070] Alternatively, the positive electrode plate includes a first current collector area and a first empty foil area, wherein the first empty foil area is located at the edge of the first current collector area and can extend along the length direction of the positive electrode plate, and the first empty foil area is configured to form a positive electrode full tab by bending.

[0071] In one embodiment, the positive electrode sheet may include a first current collector region and a positive electrode tab 11 connected to the first current collector region. At this time, the welding of the positive electrode tab 11 may be performed before or after winding, so as to facilitate the manufacture of different battery cell structures and subsequent maintenance operations.

[0072] In another embodiment, the positive electrode plate may also include a first current collector area and a first empty foil area, and the first current collector area is coated with a positive active material for storing and releasing electrical energy. The first empty foil area may be an area formed by removing the positive active material, that is, the positive active material is not coated. Among them, the first empty foil area is located at the edge of the first current collector area, and the first empty foil area can at least surround the length side of the first current collector area, so as to form a positive full-pole ear after bending, increase the contact area for current conduction, reduce the internal resistance, and thus improve the charge and discharge rate and power output of the battery cell structure. Moreover, the positive full-pole ear structure can be formed by a simple bending process, without the need for additional welding or connection steps, which simplifies the production process and reduces production costs.

[0073] Among them, the positive electrode full-ear structure makes the current distribution on the positive electrode plate more uniform, avoiding the problem of local overheating and overreaction, and helping to extend the service life of the battery structure. In addition, the positive electrode full-ear structure also enhances the mechanical stability of the battery structure and improves its ability to resist impact and vibration.

[0074] Optionally, the empty foil area includes a first area 221, a second area 222 and a third area 223, the third area 223 is bent and connected between the first area 221 and the second area 222, and at least one of the first area 221, the second area 222 and the third area 223 can extend along the length direction of the pole piece and can be bent to form a full pole ear.

[0075] like Figure 3 As shown, the first region 221, the second region 222 and the third region 223 can be arranged to form a "F"-shaped structure and surround the three edges of the second current collector region 21, and at least one of the three regions extends along the length direction of the pole piece so that a full pole ear can be formed after bending. The design of the multi-region empty foil area makes the processing and assembly process of the battery cell structure simpler and more efficient. Through precise cutting and bending processes, the required full pole ear structure can be easily formed.

[0076] In another embodiment, the empty foil area may include only one region, which extends along the length direction of the pole piece so as to form a full pole ear after bending.

[0077] In another embodiment, the empty foil area may also include two regions, at least one of which can extend along the length direction of the pole piece so as to form a full pole lug after bending.

[0078] In another embodiment, the empty foil area may include four areas. For example, the empty foil area surrounds the second current collector area 21. Two of the four areas can extend along the length direction of the pole piece to form a full pole ear after bending.

[0079] Specifically, by dividing the empty foil area into multiple regions, and extending and bending at least one region along the length direction of the pole piece to form a full pole ear, the contact area for current conduction can be increased, making the current transmission inside the battery cell structure more uniform and efficient, reducing the internal resistance, and thus improving the charge and discharge rate and power output of the battery cell structure.

[0080] Moreover, the design of multi-region empty foil area allows for more flexible use of the space inside the cell structure. By precisely controlling the width and length of each area, the capacity of the active material can be maximized without sacrificing mechanical stability, thereby improving the energy density of the battery with the cell structure. Since the empty foil area is not coated with active material, its existence itself does not increase the weight or cost of the cell structure. By optimizing the layout and size of the empty foil area, unnecessary material waste can be reduced, further reducing production costs.

[0081] According to another embodiment of the present application, a button battery is provided, comprising a housing and the battery cell structure, wherein the battery cell structure is located in the housing, and the full tab is welded to the housing. The button battery has all the technical effects of the battery cell structure.

[0082] According to another embodiment of the present application, a method for preparing a button battery having the battery cell structure is provided, comprising:

[0083] S1. Obtain the positive electrode;

[0084] Among them, firstly, a suitable positive electrode material such as lithium iron phosphate, lithium manganese oxide, lithium cobalt oxide or ternary material is selected as the positive electrode active material; then the selected positive electrode active material, conductive agent, binder (are mixed evenly in a certain proportion to form a positive electrode slurry; then the positive electrode slurry is evenly coated on the positive electrode collector to form a positive electrode coating; finally, the coated positive electrode collector is dried, pressed and sliced ​​to obtain the required positive electrode sheet.

[0085] S2. Obtain a negative electrode sheet, the negative electrode sheet comprising a second current collector region 21 and a second empty foil region 22, the second empty foil region 22 being located at an edge of the second current collector region 21 and being able to extend along the length direction of the negative electrode sheet;

[0086] Among them, firstly, a suitable negative electrode material such as hard carbon negative electrode, silicon carbon, natural graphite or artificial graphite is selected as the negative electrode active material; then the negative electrode active material, the conductive agent and the binder are mixed evenly in a certain proportion to form a negative electrode slurry; then the negative electrode slurry is evenly coated on the negative electrode collector to form a negative electrode coating. Note that it is necessary to leave a second empty foil area 22 during coating, and the second empty foil area 22 is located at the edge of the second current collector area 21 and can extend along the length direction of the negative electrode sheet; finally, the coated negative electrode collector is dried, pressed and sliced ​​to obtain the desired negative electrode sheet.

[0087] The negative electrode slurry may be uniformly coated on the entire negative electrode current collector to form a complete negative electrode coating; then part of the negative electrode slurry is removed to form the second empty foil area 22 , and the remaining negative electrode slurry forms the second current collector area 21 .

[0088] S3. Obtain the separator 3, stack and wind the positive electrode sheet, the separator 3 and the negative electrode sheet to obtain a battery cell structure;

[0089] Among them, a suitable membrane material can be selected to ensure that the membrane 3 has sufficient porosity and mechanical strength. Figure 4 and Figure 5 As shown, the positive electrode sheet, separator and negative electrode sheet are first stacked together in the order of positive electrode sheet-separator 3-negative electrode sheet; then the stacked materials are wound into a battery cell structure using a winding machine or manually. During the winding process, it is necessary to ensure that each layer fits tightly to avoid gaps.

[0090] S4. Bending the second empty foil area 22 and forming a negative electrode full ear;

[0091] like Figure 6 As shown, the second empty foil area 22 in the wound cell structure is bent to form a negative electrode full tab. During the bending process, the flatness of the full tab and good contact with the cell structure must be ensured.

[0092] S5. Assemble the obtained battery cell structure in a shell to form a button battery.

[0093] Among them, necessary gaskets, springs and other components can be added between the battery cell structure and the shell to ensure the stability and safety of the battery cell structure. After assembling into the shell, a syringe can be used to inject an appropriate amount of electrolyte into the gap between the battery cell structure and the shell; after injecting the electrolyte, the cover of the button battery shell is sealed to ensure that the electrolyte does not leak.

[0094] In this way, by bending the second empty foil area 22 to lead out the full negative electrode tab, there is no need to weld the negative electrode tab, thereby avoiding the risk of negative electrode tab fragmentation caused by the welding process, which helps to improve the reliability of the battery with the cell structure. In addition, the provision of the second empty foil area 22 can also reduce the exposure of active materials at the edge of the negative electrode tab, reduce the risk of short circuit caused by mechanical damage or foreign matter intrusion, and thus improve the safety of the cell structure.

[0095] In addition, in the traditional steel shell button wound battery production process, the positive and negative pole ears are led out by winding on the outside of the winding core and forming a certain angle. This structure is easy to produce current sound due to the coil effect when the battery is attached to the audio output components such as the product speaker, causing the background noise phenomenon. However, the present invention uses the design of bending the second empty foil area 22 to lead out the negative pole full ear, which can eliminate the influence of the angle between the positive pole ear and avoid the generation of current sound, so that the battery with the battery core structure will not produce current sound in the application product, significantly improving the sound quality performance of the product, reducing the background noise interference, and thus enhancing the user experience.

[0096] Among them, the traditional method also requires strict control of the angle and direction of the welded part and the winding core ear to ensure the welding quality and battery performance. This process is not only complicated and cumbersome, but also prone to welding defects or performance degradation due to improper operation. The present invention simplifies the welding process of the battery by bending the second empty foil area 22 to lead out the design of the negative electrode full ear. Since the negative electrode full ear structure makes the connection between the pole piece and the welded part more direct and stable, there is no need to strictly control the angle and direction of the welded part and the winding core ear, thereby improving welding efficiency and reducing production costs and process complexity.

[0097] Optionally, the negative electrode sheet is obtained, wherein the negative electrode sheet comprises a second current collector area 21 and a second empty foil area 22, wherein the second empty foil area 22 is located at an edge of the second current collector area 21 and can extend along the length direction of the negative electrode sheet, and comprises:

[0098] coating the negative electrode active material;

[0099] Part of the negative electrode active material is removed to form the second empty foil area 22 , and the remaining negative electrode active material forms the second current collector area 21 , and the width of the second empty foil area 22 is in the range of 2 mm to 4 mm.

[0100] Specifically, the negative electrode active material, i.e., the negative electrode slurry, can be uniformly coated on the entire negative electrode current collector to form a complete negative electrode coating; then, part of the negative electrode slurry is removed to form the second empty foil area 22, and the remaining negative electrode slurry forms the second current collector area 21. The removal method includes but is not limited to laser cutting, mechanical cutting and chemical etching, and part of the negative electrode active material can be removed along a preset boundary line. This boundary line also defines the boundary between the second current collector area 21 and the second empty foil area 22.

[0101] In the process of removing the negative electrode active material, the accuracy and consistency of the boundary line should be ensured to avoid damage to the second current collector area 21 or leaving unnecessary residues. After removing part of the negative electrode active material, the negative electrode sheet can be dried to remove residual solvent and moisture. Then, a sheet pressing process is performed to improve the density and mechanical strength of the negative electrode sheet. Finally, the negative electrode sheet is sliced ​​to obtain a negative electrode sheet of the desired size and shape.

[0102] The width of the empty foil area is set to be in the range of 2 mm to 4 mm, which can facilitate the bending process while ensuring the balance between the mechanical strength and current conduction performance of the formed full pole ear. In addition, the stability of the battery cell structure during use can be ensured, and the loss of battery capacity can be avoided, thereby ensuring the energy density of the battery with the battery cell structure.

[0103] Optionally, removing part of the negative electrode active material and forming the second empty foil area 22 includes:

[0104] Use alcohol wiping or laser removal to remove part of the negative electrode active material.

[0105] Specifically, the removal method includes but is not limited to laser cutting, mechanical cutting, alcohol wiping and chemical etching, and part of the negative electrode active material can be removed along a preset boundary line. This boundary line also defines the boundary between the second current collector area 21 and the second empty foil area 22.

[0106] Among them, laser technology has the characteristics of high precision and high energy, and can quickly and accurately remove the negative electrode active material in the preset area without affecting the surrounding area. By accurately controlling the parameters of the laser, it can be ensured that the width, length and shape of the second empty foil area 22 meet the design requirements, providing reliable guarantee for the formation of the full-electrode ear structure. In addition, no additional chemical reagents or tools are required during the laser removal process, which reduces production costs and environmental pollution.

[0107] Among them, for alcohol wiping, alcohol, as an organic solvent, can effectively dissolve the binder components in the negative electrode active material, thereby achieving local removal of the material during the wiping process. By controlling the strength, time and range of wiping, the purpose of accurately controlling the size of the empty foil area can also be achieved. Moreover, the alcohol wiping method is simple and easy, does not require complex equipment and processes, and is suitable for large-scale production. In addition, as a common industrial solvent, alcohol is relatively cheap, which further reduces production costs.

[0108] Optionally, after removing part of the negative electrode active material and forming the second empty foil area 22, the method further includes:

[0109] Rolling the negative electrode sheet;

[0110] Cutting the negative electrode sheet;

[0111] The cutting position is located at the boundary between the second empty foil area 22 and the second current collector area 21 .

[0112] like Figures 1 to 3 A cutting process is shown, which can obtain a small piece of negative electrode sheet, and is also convenient for improving the utilization rate of the negative electrode sheet. Setting the cutting position at the junction of the second empty foil area 22 and the second current collector area 21 can also avoid the cutting process from causing damage to the negative electrode active material in the second current collector area 21.

[0113] Optionally, the positive electrode sheet, the separator 3 and the negative electrode sheet are stacked and wound to obtain a battery core structure, comprising:

[0114] The second empty foil area 22 and the positive electrode tab 11 of the positive electrode sheet are respectively placed at two ends of the battery structure, and the top of the second empty foil area 22 exceeds the top of the diaphragm 3 along the width direction of the battery structure.

[0115] Specifically, during the winding process, ensure that the second empty foil area 22 and the positive electrode tab 11 of the positive electrode sheet are respectively placed at both ends of the battery cell structure, so that the formed negative electrode full tab and the positive electrode tab 11 are respectively located at both ends of the battery cell structure, facilitating the formation of a battery structure.

[0116] Moreover, the top of the second empty foil area 22 is arranged to exceed the top of the diaphragm 3 along the width direction or the height direction of the battery cell structure, so that a complete and reliable negative electrode full ear can be formed after the second empty foil area 22 is bent, and potential risks caused by the contact between the edge of the diaphragm 3 and the negative electrode full ear during processing or use, such as scratches, breakage, etc., are avoided, thereby enhancing the stability of the battery cell structure.

[0117] Optionally, assembling the obtained battery cell structure in a housing to form a button battery comprises:

[0118] Welding the negative electrode full tab to one end of the shell;

[0119] Fill with liquid and seal;

[0120] The positive electrode tab 11 of the positive electrode sheet is welded to the other end of the shell.

[0121] Specifically, before welding the negative electrode tab, the negative electrode tab and the shell can be cleaned to remove impurities such as oil, dust and oxide on the surface to improve the welding quality. For example, ultrasonic cleaning, alcohol wiping or plasma cleaning can be used for cleaning.

[0122] Depending on the material of the negative electrode full tab and the material of the shell, suitable welding processes such as laser welding and resistance welding can be selected. Among them, laser welding has the characteristics of high precision, high energy density and rapid cooling, and is suitable for welding thin materials. Resistance welding uses the heat generated by the current to melt the contact surface and connect them together, which is suitable for welding various materials.

[0123] During the welding process, the full tab of the negative electrode needs to be aligned with the welding position of the shell to ensure that the two are in close contact; after welding, the electrolyte can be injected into the shell using a liquid injection device to ensure that the electrolyte completely soaks the battery structure; then the opening end of the shell can be sealed using a sealing device. Among them, laser sealing, ultrasonic sealing or mechanical pressing sealing can be used for sealing.

[0124] For a double-shell product, the positive electrode tab can be welded to the other end of the shell from the outside to obtain a button battery. For a single-shell product, the positive electrode tab can be welded to the other end of the shell first, and then the liquid is injected and sealed to obtain a button battery.

[0125] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0126] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A battery cell structure, characterized in that: include: A first pole piece (1) and a second pole piece (2), wherein the first pole piece (1) and the second pole piece (2) have opposite polarities, and at least one of the first pole piece (1) and the second pole piece (2) comprises a current collector region and a hollow foil region, wherein the hollow foil region is located at an edge of the current collector region and can extend along the length direction of the pole piece, and the hollow foil region is configured to form a full pole ear by bending, and the width of the hollow foil region ranges from 2 mm to 4 mm.

2. The battery cell structure according to claim 1, characterized in that: It also comprises a diaphragm (3), wherein the diaphragm (3) is arranged between the first pole piece (1) and the second pole piece (2), and along the width direction of the battery core structure, the top of the empty foil area exceeds the top of the diaphragm (3).

3. The battery cell structure according to claim 2, characterized in that: The top of the empty foil area exceeds the top of the diaphragm (3) by 1.5 mm to 3.5 mm.

4. The battery cell structure according to claim 1, characterized in that: The first pole piece (1) is a positive pole piece, the second pole piece (2) is a negative pole piece, the negative pole piece comprises a second current collector area (21) and a second empty foil area (22), the second empty foil area (22) is located at the edge of the second current collector area (21) and can extend along the length direction of the negative pole piece, and the second empty foil area (22) is configured to form a negative full pole ear after being bent.

5. The battery cell structure according to claim 4, characterized in that: The positive electrode plate comprises a first current collector region and a positive electrode tab (11), wherein the positive electrode tab (11) is connected to the first current collector region; Alternatively, the positive electrode plate includes a first current collector area and a first empty foil area, wherein the first empty foil area is located at the edge of the first current collector area and can extend along the length direction of the positive electrode plate, and the first empty foil area is configured to form a positive electrode full tab by bending.

6. The battery cell structure according to claim 1, characterized in that: The empty foil area comprises a first area (221), a second area (222) and a third area (223); the third area (223) is bent and connected between the first area (221) and the second area (222); and at least one of the first area (221), the second area (222) and the third area (223) can extend along the length direction of the pole piece and can be bent to form a full pole ear.

7. A button battery, characterized in that: It comprises a shell and the battery cell structure according to any one of claims 1 to 6, wherein the battery cell structure is located in the shell, and the full tab is welded to the shell.

8. A method for preparing a button battery having the battery core structure according to any one of claims 1 to 6, characterized in that: include: Obtain the positive electrode; Obtain a negative electrode sheet, wherein the negative electrode sheet comprises a second current collector region and a second empty foil region, wherein the second empty foil region is located at an edge of the second current collector region and can extend along a length direction of the negative electrode sheet; Obtaining a separator, and stacking and winding the positive electrode sheet, the separator and the negative electrode sheet to obtain a battery cell structure; Bending the second empty foil area to form a negative electrode full tab; The obtained battery core structure is assembled in a housing to form a button battery.

9. The preparation method according to claim 8, characterized in that: The method of obtaining a negative electrode sheet, wherein the negative electrode sheet comprises a second current collector region and a second empty foil region, wherein the second empty foil region is located at an edge of the second current collector region and can extend along the length direction of the negative electrode sheet, comprises: coating the negative electrode active material; Part of the negative electrode active material is removed to form the second empty foil area, and the remaining negative electrode active material forms the second current collector area, and the width of the second empty foil area ranges from 2 mm to 4 mm.

10. The preparation method according to claim 9, characterized in that: The method of removing part of the negative electrode active material and forming the second empty foil area comprises: Use alcohol wiping or laser removal to remove part of the negative electrode active material.

11. The preparation method according to claim 9, characterized in that: After removing part of the negative electrode active material and forming the second empty foil area, the method further includes: Rolling the negative electrode sheet; Cutting the negative electrode sheet; The cutting position is located at the boundary between the second empty foil area and the second current collector area.

12. The preparation method according to claim 8, characterized in that: The positive electrode sheet, the separator and the negative electrode sheet are stacked and wound to obtain a battery core structure, comprising: The second empty foil area and the positive electrode tab of the positive electrode sheet are respectively placed at two ends of the battery structure, and the top of the second empty foil area exceeds the top of the diaphragm along the width direction of the battery structure.

13. The preparation method according to claim 8, characterized in that: The method of assembling the obtained battery cell structure in a housing to form a button battery comprises: Welding the negative electrode full tab to one end of the shell; Fill with liquid and seal; The positive electrode tab of the positive electrode sheet is welded to the other end of the shell.

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