Pre-lithiated cylindrical roll core and pre-lithiation method thereof

By combining lithium supplement material and termination tape on the surface of the cylindrical core, the irreversible capacity loss problem during the first charging and discharging of lithium-ion batteries is solved, the Coulomb efficiency is improved, and the pre-lithiation process is simplified, and the safety risks are reduced.

CN120413756APending Publication Date: 2025-08-01HEFEI GUOXUAN HIGH TECH POWER ENERGY
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Patent Information

Application Number
CN202510553838.1
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-04-29
Publication Date
2025-08-01

AI Technical Summary

Technical Problem

There are problems of irreversible capacity loss and low efficiency of the first Coulomb during the first charging and discharging process, especially for new silicon anode materials, and the existing negative electrode prelithiation method is complex and has safety risks.

Method used

The composite lithium supplement material and the termination tape are used to prelithiate directly on the surface of the cylindrical core, including the composite of negative electrode copper foil, composite separator and metal lithium foil materials, and the composite lithium supplement material is formed by hot rolling, and the termination tape is pasted on the surface of the cylindrical core to achieve prelithiation.

Benefits of technology

It improves the first Coulomb efficiency and circulation performance of lithium-ion batteries, simplifies the pre-lithiation process, and reduces safety risks.

✦ Generated by Eureka AI based on patent content.

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Abstract

The invention discloses a pre-lithiated cylindrical roll core and a pre-lithiation method thereof. The cylindrical roll core comprises a composite lithium supplement material, a full-tab or multi-tab cylindrical roll core, a termination adhesive tape and a diaphragm, the composite lithium supplementing material is formed by compounding a negative electrode copper foil, a composite diaphragm and two or more metal lithium foil materials, metal lithium foil materials are coated on one side of the negative electrode copper foil at intervals, and the other side of the negative electrode copper foil is coated with the composite diaphragm; positive and negative tabs are respectively arranged at two ends of the full-tab or multi-tab cylindrical roll core, and a diaphragm is covered in the middle of the full-tab or multi-tab cylindrical roll core; the bonding layer surface of the termination adhesive tape and the surface, provided with the negative electrode copper foil, of the composite lithium supplementing material are covered with an ending adhesive tape, and one end of the negative electrode copper foil is arranged in a free mode, coincides with the negative electrode lug end of the full-lug or multi-lug cylindrical roll core and is pasted to the surface of the full-lug or multi-lug cylindrical roll core by a circle through the ending adhesive tape. According to the invention, lithium supplement is carried out on the battery at the level of the cylindrical battery core, the pre-lithium amount is controllable, and relatively high first coulombic efficiency and cycle performance are realized.
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Description

Technical Field

[0001] The present invention belongs to the technical field of lithium battery production, and relates to a prelithiated cylindrical winding core and a prelithiation method thereof. Background Art

[0002] Lithium-ion batteries often have the problem of low initial efficiency of the negative electrode, especially for new silicon negative electrode materials, the initial efficiency is lower than that of graphite. During the first charge and discharge process of lithium-ion batteries, there is generally an irreversible capacity loss problem and a part of the lithium in the positive electrode is consumed, resulting in low initial Coulomb efficiency and low cycle performance. Prelithiation of the negative electrode can make up for the irreversible loss of lithium in the negative electrode, thereby improving the initial Coulomb efficiency and cycle performance of the whole battery.

[0003] Currently, the method of negative electrode prelithiation generally prelithiates the negative electrode material in advance and then prepares the negative electrode sheet, and then assembles it with the positive electrode, separator, electrolyte, etc. into an electric core. This method of prelithiating the negative electrode material in advance has a complex process, poor prelithiation effect and great safety risks in manufacturing. Summary of the Invention

[0004] The purpose of the present invention is to provide a prelithiated cylindrical winding core and a prelithiation method thereof.

[0005] The present invention provides a prelithiated cylindrical winding core, which includes a composite lithium supplement material, a cylindrical winding core with a full tab or multiple tabs, a termination tape, and a separator;

[0006] The composite lithium supplement material is composed of a negative copper foil, a composite separator, and two or more metal lithium foil materials; the metal lithium foil materials are arranged at intervals on one side of the negative copper foil, and the other side of the negative copper foil is laminated with the composite separator;

[0007] Positive tabs and negative tabs are respectively arranged at both ends of the cylindrical winding core with a full tab or multiple tabs, and the separator is laminated in the middle to separate the positive tab and the negative tab;

[0008] The bonding surface of the termination tape is laminated with the side of the negative copper foil of the composite lithium supplement material to form a finishing tape, and one end of the negative copper foil is free and coincides with the negative tab end of the cylindrical winding core with a full tab or multiple tabs, and is pasted on the surface of the cylindrical winding core with a full tab or multiple tabs for one week through the finishing tape.

[0009] The present invention directly prelithiates on the surface of the cylindrical winding core to supplement lithium, thereby improving the initial Coulomb efficiency and cycle performance of the lithium-ion battery.

[0010] In the above-mentioned prelithiated cylindrical winding core, the metal lithium foil materials are correspondingly distributed on the negative copper foil.

[0011] In the above-mentioned pre-lithiated cylindrical wound core, the composite separator uses a polymer-coated separator, and the polymer is a conventional separator substrate, specifically including PP or PE polymer.

[0012] In the above-mentioned pre-lithiated cylindrical wound core, one end of the negative copper foil that coincides with the negative electrode tab end of the cylindrical wound core with a full tab or multiple tabs is set to the shape of the full tab or multiple tabs.

[0013] In the above-mentioned pre-lithiated cylindrical wound core, the shape of the tab is any one of a trapezoid, a parallelogram, and a rectangle, and the tab shape can be changed according to the cylindrical wound core process.

[0014] In the above-mentioned pre-lithiated cylindrical wound core, the length and width of the termination tape are both greater than the length and width of the negative copper foil.

[0015] In the above-mentioned pre-lithiated cylindrical wound core, the length of the negative copper foil is 80 - 100 mm, and the width is 40 - 60 mm;

[0016] The length of the termination tape is 100 - 120 mm, and the width is 80 - 100 mm;

[0017] The thickness of the lithium foil material is 5 μm - 10 μm, and the distance between the two lithium foil materials is 15 mm - 40 mm.

[0018] The present invention also provides a pre-lithiation method for the above-mentioned cylindrical wound core, including the following steps: 1) According to the tab shape of the cylindrical wound core with a full tab or multiple tabs, one end of the negative copper foil is laser-cut into the same shape;

[0019] 2) Two or more spaced-apart metal lithium foil materials are laminated on one side of the negative copper foil, and the metal lithium foil materials on the surface of the negative copper foil are correspondingly distributed, and a PET protective film is adhered to the surface of the lithium foil material;

[0020] 3) The other side of the negative copper foil processed in step 2) and the composite separator are laminated through a hot roll to form the composite lithium supplementation material;

[0021] 4) The end tape formed by laminating the termination tape and the composite lithium supplementation material is pasted around the surface of the cylindrical wound core. Before the end tape adheres to the cylindrical wound core, the PET protective film on the surface of the metal lithium foil material is peeled off; and the end of the negative copper foil in the composite lithium supplementation material cut into the tab shape coincides with the negative electrode tab end of the cylindrical wound core to complete the pre-lithiation of the cylindrical battery cell.

[0022] In the above-mentioned pre-lithiation method, the composite separator and the negative copper foil laminated with the metal lithium foil material are laminated through a hot roll.

[0023] In the above pre-lithiation method, the temperature of the thermal roll lamination can be 70°C to 100°C.

[0024] The technical solution of the present invention has the following advantages:

[0025] 1. The pre-lithiation method provided by the present invention performs lithium supplementation on the battery at the cylindrical battery cell level. By using a ready-made composite lithium supplementation material and directly laminating it with a termination tape to pre-lithiate the cylindrical battery cell, the pre-lithium amount is controllable, and an appropriate amount of lithium can be supplemented to achieve a high first Coulombic efficiency and cycling performance.

[0026] 2. The pre-lithiation method provided by the present invention is simple, has low environmental requirements, is easy to operate, and can laminate the lithium foil, negative copper foil, and composite separator into one body, avoiding the lamination of the lithium foil and lithium supplementation before processing such as die-cutting, further reducing the safety risk caused by the active nature of lithium. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Shows a schematic diagram of the overall cylindrical wound core after pre-lithiation of the present invention;

[0028] Figure 2 Shows a top view structural schematic diagram of the composite lithium supplementation material of the present invention;

[0029] Figure 3 Shows a side view structural schematic diagram of the composite lithium supplementation material of the present invention;

[0030] Figure 4 Shows a top view schematic diagram of the composite of the lithium supplementation material and the tape of the present invention;

[0031] Figure 5 Shows a side view schematic diagram of the composite of the lithium supplementation material and the tape of the present invention;

[0032] Each label in the figure is as follows: 1 composite lithium supplementation material with separator; 101 negative copper foil; 102 composite separator; 103 metal lithium foil material 1; 104 PET protective film; 105 metal lithium foil material 2; 2 termination tape; 3 cylindrical wound core with full tab or multi-tabs; 301 negative tab; 302 positive tab; 303 separator. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods.

[0034] Unless otherwise specified, the materials, reagents, etc. used in the following examples can all be obtained from commercial channels.

[0035] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] As Figure 1 shown, it is a schematic diagram of the whole after the cylindrical core is prelithiated according to the present invention, which includes a composite lithium supplement material 1, a cylindrical core 3 with a full tab or multiple tabs, a termination tape 2, and a separator 301;

[0037] As Figure 2 shown, the composite lithium supplement material 1 is composed of a negative copper foil 101, a composite separator 102, two metal lithium foil materials 1103 and a metal lithium foil material 2 105; a metal lithium foil material is arranged at intervals on one side of the negative copper foil 101, and the other side of the negative copper foil 101 is laminated with the composite separator 102;

[0038] At both ends of the cylindrical core 3 with a full tab or multiple tabs, a positive tab 302 and a negative tab 301 are respectively arranged, and a separator 303 is laminated in the middle to separate the positive tab 302 and the negative tab 301; the bonding surface of the termination tape 2 is laminated with the side of the negative copper foil 101 of the composite lithium supplement material 1 to form a finishing tape, and one end of the negative copper foil 101 is free and coincides with the negative tab end of the cylindrical core 3 with a full tab or multiple tabs, and is pasted on the surface of the cylindrical core 3 with a full tab or multiple tabs for one week through the finishing tape.

[0039] Further, the metal lithium foil materials (103, 105) are correspondingly distributed on the negative copper foil 101.

[0040] Further, the composite separator adopts a polymer-coated separator.

[0041] Further, one end of the negative copper foil that coincides with the negative tab end of the cylindrical core with a full tab or multiple tabs is set in the shape of a full tab or multiple tabs.

[0042] Further, the shape of the tab is any one of a trapezoid, a parallelogram and a rectangle, and the tab shape can be changed according to the cylindrical core process.

[0043] Further, the length and width of the termination tape are both greater than the length and width of the negative copper foil.

[0044] The length of the negative copper foil is 80 - 100 mm, and the width is 40 - 60 mm;

[0045] The length of the termination tape is 100 - 120 mm, and the width is 80 - 100 mm;

[0046] The thickness of the lithium foil material is 5 μm - 10 μm, and the distance between the two lithium foil materials is 15 mm - 40 mm.

[0047] The present invention will be further described below in conjunction with the accompanying drawings.

[0048] Embodiment

[0049] A prelithiation method for a cylindrical core includes the following steps:

[0050] First, after the negative electrode copper foil 101 is laminated with the metallic lithium foil material 103, it is then laminated with the composite separator 102 to form the composite lithium supplement material 1. The composite lithium supplement material 1 is then combined with the termination tape 2. When the cylindrical core 3 with a full pole ear or multiple pole ears reaches the blanking station, the combination of the termination tape 2 and the composite lithium supplement material 1 is pasted around the cylindrical core 3 along with the circumferential movement of the winding needle. At this time, the prelithiation of the cylindrical core 3 with a full pole ear or multiple pole ears is completed;

[0051] Among them, as Figure 2 shown, the composite lithium supplement material 1 is composed of the lamination of the negative electrode copper foil 101, the composite separator 102, the metallic lithium foil material 103, and the PET protective film 104. The length of the negative electrode copper foil 101 is 80 - 100 mm, and the width is 40 - 60 mm. At the same time, one end of the negative electrode copper foil 101 can be trapezoidal, parallelogram, or rectangular according to the shape of the pole ear cut by laser, and the pole ear shape can be changed according to the cylindrical core process; at the same time, two or more spaced metallic lithium foil materials 1 103 and metallic lithium foil material 2 105 are laminated on one side of the negative electrode copper foil 101, and the metallic lithium foil materials 103 - 105 located on the surface 101 of the negative electrode copper foil 101 are correspondingly distributed; the lamination of the metallic lithium foil material 103 and the negative electrode copper foil 101 is preferably carried out by roll lamination. At this time, the metallic lithium can be adjusted, and the prelithiation amount can be adjusted according to the actual situation, ensuring the effect of lithium supplementation;

[0052] Among them, the surface of the metallic lithium foil material 103 is adhered with a PET protective film 104 (the PET protective film 104 with lithium foil belongs to a mature product and can be purchased from the market). On the one hand, it reduces the procurement cost, and on the other hand, it reduces the risk of composite manufacturing of the metallic lithium foil material.

[0053] As Figure 3 the schematic side view composition diagram of the composite lithium supplement material, the two metallic lithium foil materials 1 103 and metallic lithium foil material 2 105 and the composite separator 102 are combined through a roller mechanism device to form the composite lithium supplement material 1; in the above process, the composite separator 102 is an adhesive-coated separator, and the composite separator 102 and the metallic lithium foil materials 1 103 and metallic lithium foil material 2 105 are thermally roll-laminated, and the thermal lamination temperature is 70°C - 100°C.

[0054] As Figure 4Top view schematic diagram after the lithium supplementing material is compounded with the tape; the composite lithium supplementing material 1 is pasted on the bonding surface of the termination tape 2; the specification of the termination tape is 100 - 120 mm in length and 80 - 100 mm in width; and the positions of the composite lithium supplementing material 1 on the termination tape 2 are A, B, and C respectively; mainly to ensure that the negative electrode foil end 101 in the composite lithium supplementing material 1 coincides with the negative electrode tab 301 end of the cylindrical core, so as to ensure the operation of the subsequent processes;

[0055] When the cylindrical core 3 is at the winding needle blanking station, the end tape formed by the compounding of the termination tape 2 and the composite lithium supplementing material 1 is pasted around the surface of the cylindrical core 3, and before the end tape bonds to the core, the PET protective film 104 is peeled off.

[0056] The pre-lithiation method provided by the present invention supplements lithium to the battery at the cylindrical battery cell level. By directly compounding the ready-made composite lithium supplementing material with the termination tape to pre-lithiate the cylindrical battery cell, the pre-lithiation amount is controllable, and an appropriate amount of lithium can be supplemented to achieve a higher initial Coulomb efficiency and cycle performance;

[0057] The pre-lithiation method provided by the present invention is simple, has low requirements for the environment, is easy to operate, and combines the metallic lithium foil material, negative electrode copper foil, and separator into one body, avoiding compounding the lithium foil and supplementing lithium before processes such as die cutting, and further reducing the safety risks caused by the active nature of lithium.

[0058] The technical solutions provided by the embodiments of the present invention have been introduced in detail above. Specific examples are used in this article to elaborate on the principles and implementation manners of the embodiments of the present invention. The descriptions of the above embodiments are only applicable to help understand the principles of the embodiments of the present invention; at the same time, for those of ordinary skill in the art, according to the embodiments of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A pre-lithiated cylindrical winding core, characterized in that, It includes a composite lithium supplement material, a cylindrical winding core with a full tab or multiple tabs, a termination tape, and a separator; The composite lithium supplement material is composed of a negative copper foil, a composite separator, and two or more metal lithium foil materials laminated together; on one side of the negative copper foil, the metal lithium foil materials are laminated at intervals, and on the other side of the negative copper foil, it is laminated with the composite separator; At both ends of the cylindrical winding core with a full tab or multiple tabs, a positive tab and a negative tab are respectively provided, and the separator is laminated in the middle to separate the positive tab and the negative tab; The bonding surface of the termination tape is laminated with the side of the negative copper foil of the composite lithium supplement material to form a finishing tape, and one end of the negative copper foil is free and coincides with the negative tab end of the cylindrical winding core with a full tab or multiple tabs, and is pasted on the surface of the cylindrical winding core with a full tab or multiple tabs for one week through the finishing tape.

2. The prelithiated cylindrical wound core according to claim 1, wherein The metal lithium foil materials are correspondingly distributed on the negative copper foil.

3. The prelithiated cylindrical wound core according to claim 1 or 2, characterized in that, The composite separator adopts a polymer-coated separator.

4. The prelithiated cylindrical wound core according to claim 1 or 2, characterized in that, One end of the negative copper foil that coincides with the negative tab end of the cylindrical winding core with a full tab or multiple tabs is set to the shape of the full tab or multiple tabs.

5. The prelithiated cylindrical wound core according to claim 1 or 2, characterized in that The shape of the tab is any one of a trapezoid, a parallelogram, and a rectangle.

6. The prelithiated cylindrical wound core according to claim 1 or 2, characterized in that The length and width of the termination tape are both greater than the length and width of the negative copper foil.

7. The prelithiated cylindrical wound core according to claim 1 or 2, characterized in that, The length of the negative copper foil is 80 - 100 mm, and the width is 40 - 60 mm; The length of the termination tape is 100 - 120 mm, and the width is 80 - 100 mm; The thickness of the lithium foil material is 5 μm - 10 μm, and the distance between the two lithium foil materials is 15 mm - 40 mm.

8. The pre-lithiation method of the cylindrical winding core according to any one of claims 1 - 7, comprising the following steps: 1) According to the shape of the tab of the cylindrical winding core with a full tab or multiple tabs, one end of the negative copper foil is laser-cut into the same shape; 2) On one side of the negative copper foil, two or more metal lithium foil materials are laminated at intervals, and the metal lithium foil materials on the surface of the negative copper foil are correspondingly distributed, and the surface of the lithium foil material is adhered with a PET protective film; 3) The other side of the negative copper foil processed in step 2) is laminated with the composite separator through a hot roll to form the composite lithium supplement material; 4) The finishing tape formed by laminating the termination tape and the composite lithium supplement material is pasted on the surface of the cylindrical winding core for one week, and before the finishing tape bonds the cylindrical winding core, the PET protective film is peeled off; and the end of the negative copper foil with the cut tab shape in the composite lithium supplement material coincides with the negative tab end of the cylindrical winding core to complete the pre-lithiation of the cylindrical battery cell.

9. The prelithiated cylindrical wound core according to claim 8, wherein, The composite separator and the negative copper foil laminated with the metal lithium foil material are hot-rolled.

10. The prelithiated cylindrical wound core according to claim 9, wherein, The temperature of the hot roll lamination is 70°C - 100°C.