Methods for preparing wound battery cells

Abstract

This application relates to the field of battery technology, specifically to a method for preparing a wound battery cell. The method includes: providing a wound core structure, the wound core structure including a separator, a first electrode, and a second electrode, the separator being located between the first electrode and the second electrode, the first electrode including a first empty foil region, and the second electrode including a second empty foil region, the first empty foil region and the second empty foil region being located on the same side of the wound core structure; controlling the first electrode to move, causing the first empty foil region to extend relative to the second empty foil region of the second electrode; cutting the first empty foil region to form a first tab; controlling the second electrode to cause the second empty foil region to extend relative to the first tab; and cutting the second empty foil region to form a second tab. This application can reduce or even eliminate tab misalignment deviations, improving cell performance.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a method for preparing wound battery cells. Background Technology

[0002] There are two main manufacturing processes for wound battery cells: winding and stacking. Due to factors such as production capacity and cost, winding is the dominant process.

[0003] In the fabrication of wound battery cells, related technologies first calculate the spacing between the tabs. Before winding, the empty foil area of ​​the electrode sheet is laser-divided according to the tab spacing to form the tabs. Subsequently, the electrode sheet is wound so that the tabs overlap. However, the roll diameter varies with the number of layers, and the thickness and flatness of the electrode sheet fluctuate. The pre-cut laser-cut tabs are misaligned after the electrode sheet is wound. Moreover, the more layers wound, the greater the fluctuation in the thickness and flatness of the electrode sheet, and the greater the misalignment deviation of the tabs, which affects the performance of the battery cell. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, this invention proposes a method for preparing a wound battery cell, which can reduce or even eliminate misalignment deviations of the electrode tabs and improve cell performance.

[0005] In a first aspect, this application provides a method for preparing a wound battery cell, comprising:

[0006] A core structure is provided, the core structure including a diaphragm, a first electrode sheet and a second electrode sheet, the diaphragm being located between the first electrode sheet and the second electrode sheet, the first electrode sheet including a first empty foil area, the second electrode sheet including a second empty foil area, and the first empty foil area and the second empty foil area being located on the same side of the core structure;

[0007] Control the movement of the first electrode plate so that the first empty foil area extends out relative to the second empty foil area of ​​the second electrode plate;

[0008] The first empty foil region is cut to form the first electrode tab;

[0009] Control the second electrode plate to make the second empty foil region extend relative to the first electrode tab;

[0010] The second empty foil region is cut to form the second tab.

[0011] According to the method for preparing a wound battery cell provided in this application, by providing a wound core structure, controlling the movement of the first electrode sheet in the wound core structure so that the first empty foil area of ​​the first electrode sheet extends relative to the second empty foil area of ​​the second electrode sheet, cutting the first empty foil area to form a first electrode tab, reducing or even eliminating the misalignment deviation of the first electrode tab, controlling the second electrode sheet in the wound core structure so that the second empty foil area extends relative to the first electrode tab, cutting the second empty foil area to form a second electrode tab, reducing or even eliminating the misalignment deviation of the second electrode tab, and improving the battery cell performance.

[0012] According to embodiments of this application, before forming the core structure, the method further includes:

[0013] A plurality of adhesive tapes are spaced apart on the first empty foil area, one end of the adhesive tapes being connected to the first empty foil area and the other end of the adhesive tapes extending out of the first empty foil area;

[0014] The step of controlling the movement of the first electrode to make the first empty foil region extend relative to the second empty foil region of the second electrode includes:

[0015] The tape moves the first electrode, causing the first empty foil area to extend completely relative to the second empty foil area.

[0016] According to an embodiment of this application, the position of the tape in the first empty foil area is offset from the position in the first empty foil area used to form the first tab.

[0017] According to an embodiment of this application, the spacing of the tape arrangement corresponds to the spacing of the first tab arrangement.

[0018] According to an embodiment of this application, the first electrode includes a first current collector, a first material layer disposed on at least one side surface of the first current collector, and a protective layer disposed on at least one side edge of the first material layer, wherein the first empty foil area is located at the edge of the first current collector.

[0019] According to embodiments of this application, the first empty foil region extending relative to the second empty foil region of the second electrode sheet means:

[0020] The edge of the protective layer near the first empty foil area is flush with the edge of the second empty foil area, or the protective layer near the first empty foil area extends out relative to the second empty foil area.

[0021] According to an embodiment of this application, the step of controlling the second electrode to extend the second empty foil region relative to the first electrode tab includes:

[0022] Control the movement of the second electrode, the diaphragm, and the first electrode, so that the protective layer on the side near the first empty foil area is retracted towards the inside of the core structure relative to the edge of the diaphragm;

[0023] Control the movement of the second electrode plate so that the second empty foil area extends relative to the first electrode tab.

[0024] According to an embodiment of this application, the protective layer on the side closest to the first empty foil area is recessed by a distance of 2mm to 3mm relative to the edge of the diaphragm.

[0025] According to an embodiment of this application, the second electrode includes a second current collector and a second material layer disposed on at least one side surface of the second current collector, and the second empty foil area is located at the edge of the second current collector.

[0026] According to an embodiment of this application, after the step of cutting the second empty foil area, the method further includes:

[0027] Control the movement of the second electrode to cause the second material layer to retract into the inner side of the core structure relative to the edge of the diaphragm;

[0028] Control the movement of the first electrode to cause the protective layer near the first empty foil area to retract inward relative to the edge of the diaphragm towards the core structure.

[0029] According to an embodiment of this application, in the step of controlling the movement of the second electrode to retract the second material layer toward the inside of the core structure relative to the edge of the diaphragm, the edge of the second material layer near the second electrode tab is flush with the edge of the protective layer near the first electrode tab;

[0030] And / or,

[0031] In the step of controlling the movement of the first electrode to retract the protective layer near the first empty foil area toward the inside of the core structure relative to the edge of the diaphragm, the protective layer near the first empty foil area extends relative to the second material layer by a distance greater than 1 mm, and / or the protective layer near the first empty foil area retracts by a distance greater than 2 mm relative to the edge of the diaphragm.

[0032] According to an embodiment of this application, the cutting includes laser cutting;

[0033] The cutting laser power is 100W~500W; and / or,

[0034] Cutting speed is 10mm / s to 50mm / s, and / or

[0035] Each laser-cut first or second electrode layer shall not exceed 10 layers.

[0036] According to embodiments of this application, the method further includes:

[0037] Clean up the debris generated during the cutting process.

[0038] The above-described one or more technical solutions in the embodiments of this application have at least one of the following technical effects:

[0039] By providing a core structure and controlling the movement of the first electrode sheet in the core structure, the first empty foil area of ​​the first electrode sheet extends out relative to the second empty foil area of ​​the second electrode sheet. The first empty foil area is cut to form the first electrode tab, reducing or even eliminating the misalignment deviation of the first electrode tab. By controlling the second electrode sheet in the core structure to make the second empty foil area extend out relative to the first electrode tab, the second empty foil area is cut to form the second electrode tab, reducing or even eliminating the misalignment deviation of the second electrode tab, and improving the cell performance. Attached Figure Description

[0040] Figure 1 This is a schematic flowchart of the method for preparing a wound battery cell provided in the embodiments of this application;

[0041] Figure 2 This is one of the top views of the structure formed during the fabrication process of the wound battery cell provided in the embodiments of this application;

[0042] Figure 3 This is a second top view of the structure formed during the fabrication process of the wound battery cell provided in this application embodiment;

[0043] Figure 4 This is the third top view of the structure formed during the fabrication process of the wound battery cell provided in this application embodiment;

[0044] Figure 5 This is the fourth top view of the structure formed during the fabrication process of the wound battery cell provided in this application embodiment;

[0045] Figure 6 This is the fifth top view of the structure formed during the fabrication process of the wound battery cell provided in this application embodiment;

[0046] Figure 7 This is one of the side views of the structure formed during the fabrication process of the wound battery cell provided in the embodiments of this application;

[0047] Figure 8 This is the sixth top view of the structure formed during the fabrication process of the wound battery cell provided in this application embodiment;

[0048] Figure 9This is the seventh top view of the structure formed during the fabrication process of the wound battery cell provided in this application embodiment;

[0049] Figure 10 This is the eighth top view of the structure formed during the fabrication process of the wound battery cell provided in this application embodiment;

[0050] Figure 11 This is a second side view of the structure formed during the fabrication process of the wound battery cell provided in this application embodiment;

[0051] Figure 12 This is the ninth top view of the structure formed during the fabrication process of the wound battery cell provided in this application embodiment;

[0052] Figure 13 This is the tenth top view of the structure formed during the fabrication process of the wound battery cell provided in this application embodiment;

[0053] Figure 14 This is the third side view of the structure formed during the fabrication process of the wound battery cell provided in this application embodiment;

[0054] Figure 15 This is eleventh of the top views of the structure formed during the fabrication process of the wound battery cell provided in the embodiments of this application;

[0055] Figure 16 This is the fourth side view of the structure formed during the fabrication process of the wound battery cell provided in this application embodiment. Detailed Implementation

[0056] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0057] Figure 1 This is a schematic flowchart illustrating the method for preparing a wound battery cell according to an embodiment of this application.

[0058] like Figure 1 As shown, this application provides a method for preparing a wound battery cell, including steps 110 to 150.

[0059] Step 110: Provide a core structure, the core structure including a diaphragm, a first electrode sheet and a second electrode sheet, the diaphragm being located between the first electrode sheet and the second electrode sheet, the first electrode sheet including a first empty foil area, the second electrode sheet including a second empty foil area, and the first empty foil area and the second empty foil area being located on the same side of the core structure.

[0060] In this configuration, one of the first electrode 1 and the second electrode 2 is the positive electrode, and the other is the negative electrode. As an example, the first electrode 1 is the positive electrode, and the second electrode 2 is the negative electrode.

[0061] Combination Figure 2 and Figure 3 As shown, a first electrode 1 is provided, which includes a first empty foil region 11 located in a first direction X of the first electrode 1. The first empty foil region 11 is used to cut and form a first electrode tab. The first empty foil region 11 may include metal foil such as copper foil or aluminum foil.

[0062] In some embodiments, the first electrode 1 includes a first current collector, a first material layer 12 disposed on at least one side surface of the first current collector, and a protective layer 13 disposed on at least one side edge of the first material layer 12, with a first empty foil area 11 located at the edge of the first current collector. The first current collector is used to carry active material and conduct current to an external circuit. The first material layer 12 includes active material, etc. The protective layer 13 may include a ceramic layer, etc.

[0063] In the preparation process, as an example, such as Figure 2 As shown, a first initial electrode 10 is first provided. The first initial electrode 10 includes a first current collector, a first material layer 12 disposed on at least one side surface of the first current collector, a protective layer 13 disposed on both sides of the first material layer 12, and a first empty foil area 11 disposed on both sides of the first current collector. Then, combined with... Figure 3 As shown, the first initial electrode 10 is cut, that is, the first current collector and the first material layer 12 of the first initial electrode 10 are cut to obtain the first electrode 1. The first electrode 1 includes a first current collector, a first material layer 12 disposed on at least one side surface of the first current collector, a protective layer 13 disposed on one side edge of the first material layer 12, and a first empty foil area 11 disposed on one side edge of the first current collector, and the protective layer 13 is located at the edge of the first material layer 12 near the first empty foil area 11.

[0064] Combination Figure 4 and Figure 5 As shown, a second electrode 2 is provided, which includes a second empty foil region 21 located in a first direction X of the second electrode 2. The second empty foil region 21 is used for cutting to form a second electrode tab. The second empty foil region 21 may include metal foil such as copper foil or aluminum foil.

[0065] In some embodiments, the second electrode 2 includes a second current collector and a second material layer 22 disposed on at least one side surface of the second current collector, and the second empty foil area 21 is located at the edge of the second current collector.

[0066] In the preparation process, as an example, such as Figure 4 As shown, a second initial electrode 20 is first provided. The second initial electrode 20 includes a second current collector, a second material layer 22 disposed on at least one side of the first current collector, and second empty foil regions 21 disposed on both sides of the first current collector. Then, combined with... Figure 5 As shown, the second initial electrode 20 is cut, that is, the second current collector and the second material layer 22 of the second initial electrode 20 are cut to obtain the second electrode 2. The second electrode 2 includes the second current collector, the second material layer 22 disposed on at least one side of the first current collector, and the second empty foil area 21 disposed on one edge of the first current collector.

[0067] In some embodiments, the fabrication method further includes, prior to forming the core structure:

[0068] Several strips of adhesive tape are spaced apart on the first empty foil area, with one end of the tape connected to the first empty foil area and the other end of the tape extending out of the first empty foil area.

[0069] Combination Figure 6 As shown, after the first electrode 1 is formed, several adhesive tapes 3 can be attached to the first empty foil area 11, with one end of the adhesive tape 3 attached to the first empty foil area 11 and the other end of the adhesive tape 3 extending out relative to the first empty foil area 11, so that the other end of the adhesive tape is located outside the core structure after the core structure is formed.

[0070] In some embodiments, the position of the tape 3 in the first empty foil area 11 is offset from the position of the first empty foil area 11 used to form the first electrode tab, so that the tape 3 can be directly removed when the first empty foil area 11 is subsequently cut to form the first electrode tab.

[0071] In some embodiments, the spacing of the tape 3 corresponds to the spacing of the first tab.

[0072] As an example, the arrangement spacing of the first empty foil area 11 for forming the first tab is predetermined, and adhesive tape 3 is attached to the first empty foil area 11 according to the arrangement spacing so that each layer has adhesive tape 3 after the core structure is formed.

[0073] In some embodiments, tape 3 includes one or more of polyimide (PI) tape, polyester (PET) tape, polytetrafluoroethylene (PTFE) tape, and acrylic pressure-sensitive adhesive (adhesive layer). Tape 3 may also include other types of tape, which are not specifically limited here.

[0074] Combination Figure 7 As shown, the diaphragm 4, the second electrode 2, the diaphragm 4, and the first electrode 1 are sequentially stacked, and the stacked layers of the diaphragm 4, the second electrode 2, the diaphragm 4, and the first electrode 1 are wound into a core structure. The core structure includes multiple layers of first electrode 1, multiple layers of second electrode 2, and multiple layers of diaphragm 4. The multiple layers of first electrode 1 and multiple layers of second electrode 2 are alternately distributed, and a diaphragm 4 is provided between any adjacent layer of first electrode 1 and layer of second electrode 2. The diaphragm 4 serves to separate the first electrode 1 and the second electrode 2. Figure 8As shown, the first empty foil area 11 and the second empty foil area 21 are located on the same side of the core structure in the first direction X.

[0075] With the tape 3 provided in the first empty foil area 11, the tape 3 is attached to the first empty foil area 11 of the multilayer first electrode 1 of the core structure. One end of the multilayer tape 3 is connected to the first empty foil area 11, and the other end of the multilayer tape 3 is located outside the core structure, that is, the other end of the multilayer tape 3 can extend relative to the first empty foil area 11, the diaphragm 4, and the second empty foil area 21. The multilayer tape 3 overlaps at least partially in the second direction Y (the second direction Y is perpendicular to the first direction X) so that the multilayer tape 3 can be clamped and pulled at once in the future.

[0076] In some embodiments, the multilayer tape 3 may be located at the middle position of the core structure in the third direction Z (the third direction Z is perpendicular to the first direction X and the second direction Y respectively), so that when the first electrode 1 is driven by the tape 3, the first electrode 1 is subjected to balanced force so as to smoothly pull the first electrode 1.

[0077] Step 120: Control the movement of the first electrode to make the first empty foil area extend out relative to the second empty foil area of ​​the second electrode.

[0078] After the core structure is formed, the first empty foil area 11 is recessed inward relative to the edge of the second empty foil area 21 (i.e., the edge of the second empty foil area 21 away from the second material layer 22). The first empty foil area 11 of the first electrode 1 is controlled to move outward relative to the second empty foil area 21 of the second electrode 2, so that the first empty foil area 11 extends outward relative to the second empty foil area 21 of the second electrode 2. In some embodiments, the first empty foil area 11 also extends outward relative to the diaphragm 4.

[0079] Step 120, controlling the movement of the first electrode to extend the first empty foil region relative to the second empty foil region of the second electrode, includes:

[0080] The tape moves the first electrode, causing the first empty foil area to extend completely relative to the second empty foil area.

[0081] After the core structure is formed, the first empty foil area 11 is recessed inwards relative to the edge of the second empty foil area 21 towards the inside of the core structure. One end of the tape 3 is connected to the first empty foil area 11, and the other end of the tape 3 extends relative to the second empty foil area 21. Figure 9As shown, the extended multilayer tape 3 can be gripped by the clamping mechanism and pulled outwards from the core structure, thereby moving the first empty foil area 11 of the multilayer first electrode 1 outwards from the core structure until the first empty foil area 11 of the multilayer first electrode 1 is fully extended relative to the second empty foil area 21, that is, the first empty foil area 11 and the second electrode 2 do not overlap in the second direction Y. In some embodiments, the first empty foil area 11 is also fully extended relative to the diaphragm 4, that is, the first empty foil area 11 and the diaphragm 4 do not overlap in the second direction Y.

[0082] The gripping mechanism may include robotic arms, etc., without specific limitations here.

[0083] In some embodiments, the first empty foil region 11 extending relative to the second empty foil region 21 of the second electrode plate 2 means:

[0084] The edge of the protective layer 13 near the first empty foil area 11 is flush with the edge of the second empty foil area 21 (i.e., the edge of the second empty foil area 21 facing away from the second material layer 22), or the protective layer 13 near the first empty foil area 11 extends partially relative to the second empty foil area 21. This ensures that the first empty foil area 11 and the second empty foil area 21 do not overlap in the second direction Y, so that the first empty foil area 11 can be subsequently cut along the second direction Y.

[0085] Step 130: Cut the first empty foil area to form the first electrode tab.

[0086] Combination Figure 10 and Figure 11 As shown, the first empty foil area 11 of the multilayer first electrode 1 is cut along the second direction Y, and the first empty foil area 11 of each layer of the first electrode 1 is cut to form the first electrode tab 5, thereby obtaining a neat multilayer first electrode tab 5, that is, the multilayer first electrode tab 5 overlaps in the second direction Y, reducing or even eliminating the misalignment deviation of the first electrode tab 5.

[0087] It should be noted that when the first empty foil area 11 is cut to form the first tab 5, the tape 3 is removed along with the cut-off first empty foil area 11, so there is no need to remove the tape 3 separately, which simplifies the preparation process.

[0088] In some embodiments, the thickness of the first tab 5 is 6 μm to 20 μm. As an example, the thickness of the first tab 5 can be 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, etc.

[0089] In some embodiments, the cutting includes laser cutting. The first empty foil region 11 of the multilayer first electrode 1 can be cut along the second direction Y by a laser cutting mechanism to obtain multilayer first electrode tabs 5 that overlap in the second direction Y.

[0090] In some embodiments, the cutting laser power is 100W to 500W. As an example, the cutting laser power can be 100W, 200W, 300W, 400W, 500W, etc.

[0091] In some embodiments, the cutting speed is 10 mm / s to 50 mm / s. As an example, the cutting speed can be 10 mm / s, 20 mm / s, 30 mm / s, 40 mm / s, 50 mm / s, etc.

[0092] The settings for cutting laser power and cutting speed can ensure cutting accuracy and efficiency, and prevent thermal damage to the electrode.

[0093] In some embodiments, the number of layers of the first tab 5 cut by laser each time is no more than 10 layers.

[0094] When the number of layers of the first electrode 1 is less than 10, the first empty foil area 11 of the multi-layer first electrode 1 can be cut by laser cutting once; when the number of layers of the first electrode 1 is more than 10, the first empty foil area 11 of the multi-layer first electrode 1 can be cut by laser cutting multiple times to prevent thermal damage to the electrode.

[0095] In some embodiments, the preparation method further includes:

[0096] Clean up the debris generated during the cutting process.

[0097] During the cutting of the first empty foil area 11, metal debris will be generated. A suction device can be installed to absorb the metal debris generated during cutting, preventing short circuits in the core.

[0098] Step 140: Control the second electrode plate so that the second empty foil area extends relative to the first electrode tab.

[0099] After the first tab 5 is formed by cutting, the second empty foil region 21 is in a state of being recessed towards the inside of the core structure relative to the edge of the first tab 5 (i.e., the edge of the first tab 5 away from the protective layer 13). By controlling the movement of the second empty foil region 21 of the second electrode 2 towards the outside of the core structure, the second empty foil region 21 can be extended relative to the first tab 5. In some embodiments, the second empty foil region 21 also extends relative to the diaphragm 4.

[0100] In some embodiments, the step of controlling the second electrode to extend the second empty foil region relative to the first electrode tab includes:

[0101] Control the movement of the second electrode, the diaphragm, and the first electrode to cause the protective layer on the side closest to the first empty foil area to retract towards the inside of the core structure relative to the edge of the diaphragm;

[0102] Control the movement of the second electrode plate so that the second empty foil area extends relative to the first electrode tab.

[0103] After the first tab 5 is formed by cutting, the second empty foil area 21 is in a state of being retracted towards the inside of the core structure relative to the edge of the first tab 5, making it impossible to pull out the multilayer second electrode 2. This can be achieved by pushing the multilayer first tab 5 and by pushing the multilayer second electrode 2 and the diaphragm 4 away from the first tab 5, thereby causing the second electrode 2 and the diaphragm 4 to move synchronously towards the first electrode 1. This controls the multilayer first electrode 1 to move towards the inside of the core structure, while simultaneously controlling the multilayer second electrode 2 and the diaphragm 4 to move towards the inside of the core structure, until the protective layer 13 near the first empty foil area 11 is retracted towards the inside of the core structure relative to the edge of the diaphragm 4 (i.e., the edge of the diaphragm 4 near the first tab 5). At this point, the second empty foil area 21 can partially extend relative to the first tab 5. In some embodiments, the second empty foil area 21 can also partially extend relative to the diaphragm 4.

[0104] In some embodiments, combined with Figure 12 As shown, the protective layer 13 near the first empty foil area 11 is recessed by a distance A relative to the edge of the diaphragm 4 by 2mm to 3mm. As an example, this recess distance A can be 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, etc.

[0105] In this embodiment, the first electrode 1, the second electrode 2, and the diaphragm 4 are moved from both sides toward the interior of the core structure, thereby improving the moving efficiency and thus improving the preparation efficiency.

[0106] Then, combine Figure 12 As shown, the clamping mechanism clamps the second empty foil area 21 that extends outward from the multilayer second electrode sheet 2, pulling the multilayer second electrode sheet 2 outward from the core structure, causing the second empty foil area 21 of the multilayer second electrode sheet 2 to move outward from the core structure until the second empty foil area 21 of the multilayer second electrode sheet 2 is fully extended relative to the first electrode tab 5, that is, the second empty foil area 21 and the first electrode tab 5 do not overlap in the second direction Y. In some embodiments, the second empty foil area 21 also extends relative to the diaphragm 4, that is, the second empty foil area 21 and the diaphragm 4 do not overlap in the second direction Y.

[0107] Step 150: Cut the second empty foil area to form the second tab.

[0108] Combination Figure 13 and Figure 14 As shown, the second empty foil area 21 of the multilayer second electrode 2 is cut along the second direction Y, and the second empty foil area 21 of each layer of the second electrode 2 is cut to form the second electrode tab 6, thereby obtaining a neat multilayer second electrode tab 6, that is, the multilayer second electrode tab 6 overlaps in the second direction Y, reducing or even eliminating the misalignment deviation of the second electrode tab 6.

[0109] Among them, combined Figure 15 and Figure 16 As shown, the second tab 6 and the first tab 5 are respectively positioned close to the opposite sides of the core structure in the third direction Z.

[0110] In some embodiments, the thickness of the second tab 6 is 6 μm to 20 μm. As an example, the thickness of the second tab 6 can be 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, etc.

[0111] In some embodiments, the cutting includes laser cutting. The second empty foil region 21 of the multilayer second electrode 2 can be cut along the second direction Y by a laser cutting mechanism to obtain multilayer second electrode tabs 6 that overlap in the second direction Y.

[0112] In some embodiments, the cutting laser power is 100W to 500W. As an example, the cutting laser power can be 100W, 200W, 300W, 400W, 500W, etc.

[0113] In some embodiments, the cutting speed is 10 mm / s to 50 mm / s. As an example, the cutting speed can be 10 mm / s, 20 mm / s, 30 mm / s, 40 mm / s, 50 mm / s, etc.

[0114] The settings for cutting laser power and cutting speed can ensure cutting accuracy and efficiency, and prevent thermal damage to the electrode.

[0115] In some embodiments, the number of layers of the second tab 6 cut by laser each time is no more than 10 layers.

[0116] When the number of layers of the second electrode 2 is less than 10, the second empty foil area 21 of the multi-layer second electrode 2 can be cut by laser cutting once; when the number of layers of the second electrode 2 is more than 10, the second empty foil area 21 of the multi-layer second electrode 2 can be cut by laser cutting multiple times to prevent thermal damage to the electrode.

[0117] In some embodiments, the preparation method further includes:

[0118] Clean up the debris generated during the cutting process.

[0119] During the cutting of the second empty foil area 21, metal debris will be generated. A suction device can be installed to absorb the metal debris generated during cutting, preventing short circuits in the core.

[0120] In some embodiments, after the step of cutting the second empty foil area, the method further includes:

[0121] Control the movement of the second electrode to cause the second material layer to retract into the inner side of the core structure relative to the edge of the diaphragm;

[0122] Control the movement of the first electrode to cause the protective layer on the side closest to the first empty foil area to retract into the inner side of the core structure relative to the edge of the diaphragm.

[0123] Combination Figure 15 As shown, the clamping mechanism clamps the multi-layer second tab 6 and pushes it toward the inside of the core structure to control the multi-layer second electrode 2 to move toward the inside of the core structure until the second material layer 22 retracts toward the inside of the core structure relative to the edge of the diaphragm 4 (i.e. the edge of the diaphragm near the second tab 6), and the second tab 6 can partially extend relative to the diaphragm 4.

[0124] In some embodiments, during the step of controlling the movement of the second electrode 2 to retract the second material layer 22 toward the inside of the core structure relative to the edge of the diaphragm 4, the edge of the second material layer 22 near the second electrode tab 6 is flush with the edge of the protective layer 13 near the first electrode tab 5.

[0125] Then, the multilayer first tab 5 is clamped by the clamping structure and pulled outwards from the core structure to control the movement of the multilayer first electrode sheet 1 outwards from the core structure until the protective layer 13 near the first empty foil area 11 is retracted inwards from the edge of the diaphragm 4 (i.e., the edge of the diaphragm near the first tab 5). The protective layer 13 may also extend at least partially relative to the second material layer 22.

[0126] In some embodiments, during the step of controlling the movement of the first electrode 1 to retract the protective layer 13 toward the inside of the core structure relative to the edge of the diaphragm 4, the protective layer 13 extends at least partially relative to the second material layer 22, and the extension distance B is greater than 1 mm, and / or the retraction distance C of the protective layer 13 relative to the edge of the diaphragm 4 is greater than 2 mm.

[0127] To address the issue of tab misalignment, related technologies employ positive electrode embossing, separator thickness control, and electrode thickness control to reduce misalignment deviations. Positive electrode embossing involves embossing the positive electrode sheet during winding, using fine-tuning of the sheet thickness to compensate for tab misalignment caused by fluctuations in electrode or separator thickness. Separator thickness control improves separator thickness consistency by narrowing the thickness tolerance of the incoming separator material, thus reducing tab misalignment caused by separator thickness fluctuations. Electrode thickness control improves electrode thickness consistency by narrowing the thickness tolerance of the incoming electrode material, thus reducing tab misalignment caused by electrode thickness fluctuations. However, these methods only allow for fine-tuning of tab dimensions and cannot completely resolve the tab misalignment problem.

[0128] This embodiment employs a winding-then-die-cutting method. First, the separator 4, the first electrode 1, and the second electrode 2 are wound into a core structure. Then, the first electrode 1 is moved so that its first empty foil area 11 extends relative to the second empty foil area 21 of the second electrode 2. The first empty foil area 11 is then cut to form the first electrode tab 5, resulting in neat, multi-layered first electrode tabs 5. This reduces or even eliminates misalignment deviations of the first electrode tabs 5. The second electrode 2 is then controlled so that its second empty foil area 21 extends relative to the first electrode tab 5. The second empty foil area 21 is then cut to form the second electrode tab 6, resulting in neat, multi-layered second electrode tabs 6. This reduces or even eliminates misalignment deviations of the second electrode tabs 6, fundamentally avoiding electrode tab misalignment problems caused by fluctuations in electrode and separator thickness. Furthermore, the debugging process is eliminated, avoiding yield losses due to material scrap. In addition, since strict control over the thickness of the electrode and separator is not required, their thickness tolerance standards can be appropriately relaxed, reducing raw material costs and improving the yield of the electrode and separator. Compared with fine-tuning solutions such as positive electrode embossing or separator thickness control in related technologies, this embodiment has better adaptability and stability, and can still ensure the precise positioning of the tab cutting even within a large range of thickness fluctuations.

[0129] Accordingly, this application also provides a wound battery cell, which is prepared by the winding battery cell preparation method described in the above embodiments.

[0130] Accordingly, this application also provides a battery, including the wound cell described in the above embodiments.

[0131] The battery can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this application embodiment is not limited to this. The battery can be cylindrical, flat, cuboid, or other shapes, and this application embodiment is not limited to this either.

[0132] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0133] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a wound battery cell, characterized in that, include: A core structure is provided, the core structure including a diaphragm, a first electrode sheet and a second electrode sheet, the diaphragm being located between the first electrode sheet and the second electrode sheet, the first electrode sheet including a first empty foil area, the second electrode sheet including a second empty foil area, and the first empty foil area and the second empty foil area being located on the same side of the core structure; Control the movement of the first electrode to make the first empty foil area extend out relative to the second empty foil area of ​​the second electrode; The first empty foil region is cut to form the first electrode tab; Control the second electrode plate to make the second empty foil region extend relative to the first electrode tab; The second empty foil region is cut to form the second electrode tab; Before forming the core structure, the following are also included: A plurality of adhesive tapes are spaced apart on the first empty foil area, one end of the adhesive tapes being connected to the first empty foil area and the other end of the adhesive tapes extending out of the first empty foil area; The step of controlling the movement of the first electrode to make the first empty foil region extend relative to the second empty foil region of the second electrode includes: The tape moves the first electrode, causing the first empty foil area to extend completely relative to the second empty foil area and the diaphragm; the position of the tape in the first empty foil area is offset from the position of the first empty foil area used to form the first electrode tab.

2. The method for preparing a wound battery cell according to claim 1, characterized in that, The spacing of the tape arrangement corresponds to the spacing of the first tab arrangement.

3. The method for preparing a wound battery cell according to claim 1, characterized in that, The first electrode includes a first current collector, a first material layer disposed on at least one side surface of the first current collector, and a protective layer disposed on at least one side edge of the first material layer, wherein the first empty foil area is located at the edge of the first current collector.

4. The method for preparing a wound battery cell according to claim 3, characterized in that, The first empty foil region extending beyond the second empty foil region of the second electrode sheet means: The edge of the protective layer near the first empty foil area is flush with the edge of the second empty foil area, or the protective layer near the first empty foil area extends out relative to the second empty foil area.

5. The method for preparing a wound battery cell according to claim 3, characterized in that, The step of controlling the second electrode to extend the second empty foil region relative to the first electrode tab includes: Control the movement of the second electrode, the diaphragm, and the first electrode, so that the protective layer on the side near the first empty foil area is retracted towards the inside of the core structure relative to the edge of the diaphragm; Control the movement of the second electrode plate so that the second empty foil area extends relative to the first electrode tab.

6. The method for preparing a wound battery cell according to claim 5, characterized in that, The protective layer is recessed by 2mm to 3mm relative to the edge of the diaphragm.

7. The method for preparing a wound battery cell according to claim 5, characterized in that, The second electrode includes a second current collector and a second material layer disposed on at least one side surface of the second current collector, and the second empty foil area is located at the edge of the second current collector.

8. The method for preparing a wound battery cell according to claim 7, characterized in that, After the step of cutting the second empty foil area, the method further includes: Control the movement of the second electrode to cause the second material layer to retract into the inner side of the core structure relative to the edge of the diaphragm; Control the movement of the first electrode to cause the protective layer to retract inward relative to the edge of the diaphragm towards the inner side of the core structure.

9. The method for preparing a wound battery cell according to claim 8, characterized in that, In the step of controlling the movement of the second electrode to retract the second material layer toward the inside of the core structure relative to the edge of the diaphragm, the edge of the second material layer near the second electrode tab is flush with the edge of the protective layer near the first electrode tab; And / or, In the step of controlling the movement of the first electrode to retract the protective layer toward the inside of the core structure relative to the edge of the diaphragm, the protective layer extends at least partially relative to the second material layer by a distance greater than 1 mm, and / or the retraction distance of the protective layer relative to the edge of the diaphragm is greater than 2 mm.

10. The method for preparing a wound battery cell according to any one of claims 1-9, characterized in that, The cutting includes laser cutting; The cutting laser power is 100W~500W; and / or, Cutting speed is 10mm / s to 50mm / s, and / or Each laser-cut first or second electrode layer shall not exceed 10 layers.

11. The method for preparing a wound battery cell according to any one of claims 1-9, characterized in that, The method further includes: Clean up the debris generated during the cutting process.

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