A double-sided intermittent lithium supplement device and method for a lithium ion battery negative electrode sheet

Abstract

The application discloses a double-sided intermittent lithium supplement device and method for a lithium ion battery negative electrode sheet, and the device comprises: an electrode sheet transmission assembly for transmitting an electrode sheet belt, a lithium belt dividing mechanism, the lithium belt dividing mechanism is used for dividing a lithium belt into lithium belt strips with equal widths, a transmission assembly is used for synchronously transmitting the lithium belt strips in cooperation with the electrode sheet belt, the lithium belt strips are equidistantly arranged on one side of the transmission assembly close to the electrode sheet belt, and a covering assembly is used for covering the lithium belt strips on the two transmission assemblies on the two sides of the electrode sheet belt respectively, so that complementary stripe structures are formed on the two sides of the electrode sheet belt. The device uses a transfer bonding mode to transfer the lithium belt strips on a guide belt to the electrode sheet belt, and simultaneously supplements lithium to the two sides of the electrode sheet belt. The production of two intermittent lithium belts is completed by using only one lithium belt dividing mechanism, lithium can be supplemented on both sides of the electrode sheet simultaneously, equipment investment cost and equipment floor area are saved. The lithium belt strips are alternately bonded on the two sides, and the heat dissipation effect is better than that during single-side continuous lithium supplement.

Description

Technical Field

[0001] This invention belongs to the field of electrode lithium replenishment technology, and more specifically, relates to a bifacial intermittent lithium replenishment device and method for a negative electrode sheet of a lithium-ion battery. Background Technology

[0002] The theoretical specific capacity of traditional graphite (Gr) anodes is only 372 mAh·g. -1 While silicon anodes are currently well-suited for meeting the energy density requirements of electric vehicles, their performance in matching positive electrodes is far from sufficient. Silicon, with its high specific capacity (4200 mAh / g) and low electromotive force approaching that of lithium metal, is highly favored as a promising next-generation anode material. However, silicon anodes experience significant volume expansion during charge and discharge, leading to irreversible lithium loss and low initial charge / discharge efficiency. Pre-lithiation technology can effectively compensate for initial lithium loss and is a promising method to address the low initial efficiency caused by silicon-based anode expansion.

[0003] There are two methods for lithium replenishment at the negative electrode: stable SLMP lithium metal powder and lithium metal foil. SLMP has a complex preparation process and is expensive, limiting its large-scale application. Continuous lithium foil replenishment is more widely used, but the continuous lithium foil replenishment process may generate a large amount of heat, and there are problems such as the risk of lithium plating and low lithium source utilization. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a bifacial intermittent lithium replenishment method for lithium-ion battery negative electrode sheets, which solves the problems of existing lithium foil lithium replenishment processes that may generate a large amount of heat, pose a risk of lithium plating, and have low lithium source utilization.

[0005] To achieve the above objectives, the present invention provides a bifacial intermittent lithium replenishment device for a lithium-ion battery negative electrode sheet, comprising: An electrode transport assembly, wherein the electrode transport assembly is used to transport electrode strips; A lithium strip dividing mechanism is used to divide a lithium strip into lithium strips of equal width. Two transmission components are provided, which are used to synchronously transmit lithium strips in conjunction with the electrode strip. The lithium strips are arranged at equal intervals on the side of the transmission components near the electrode strip. A laminating assembly is used to laminate lithium strips from the two transmission assemblies onto both sides of the electrode strip, so that complementary stripe structures are formed on both sides of the electrode strip.

[0006] Optionally, the transmission component includes a guide belt unwinding roll and a guide belt take-up roll. One end of the guide belt is connected to the guide belt unwinding roll, and the other end of the guide belt is connected to the guide belt take-up roll after passing through the lithium strip splitting mechanism and the laminating component.

[0007] Optionally, the guide belt is provided with adhesive strips that cooperate with the lithium strip, and the lithium strip splitting mechanism includes: Two convex and concave rollers, the two convex and concave rollers meshing with each other; A heating module is disposed on the convex roller and is used to heat the protruding part of the convex roller. The protruding part can heat the adhesive strip to bond the lithium strip. In use, the lithium strip and the guide strips on both sides form a three-layer structure. The lithium strip dividing mechanism divides the lithium strip into multiple lithium strips, and the multiple lithium strips are alternately attached to the two guide strips.

[0008] Optionally, the guide strip is a polyethylene terephthalate film, and the spacing and width of the adhesive strip are consistent with the width of the lithium strip.

[0009] Optionally, the lamination assembly includes a peeling mechanism and a rolling mechanism, wherein the peeling mechanism is used to peel off the guide strip, and the rolling mechanism is used to flatten the electrode strip with lithium strips laminated on both sides.

[0010] Optionally, it also includes a calendering mechanism for adjusting the thickness and width of the lithium strip.

[0011] The present invention also provides a method for bifacial intermittent lithium replenishment of a lithium-ion battery negative electrode sheet, and a bifacial intermittent lithium replenishment device based on the above-mentioned battery negative electrode sheet, comprising: The lithium strip is divided into lithium strips at equal intervals; The lithium strips are transmitted synchronously along two transmission paths. Multiple lithium strips are distributed at equal intervals along the two transmission paths, and the lithium strips along the two transmission paths are arranged alternately. The electrode strip is transmitted at a constant speed between the two transmission paths; The lithium strips on the two transmission paths are laminated to both sides of the electrode strip, so that complementary stripe structures are formed on both sides of the electrode strip.

[0012] Optionally, the step of bonding the lithium strips on the two transmission paths to both sides of the electrode strip includes: The primary roll-formed guide belt and electrode belt bond the lithium strip to the electrode belt; Peel off the guide strip to separate it from the lithium strip on the electrode strip; The lithium strips on the rolled electrode belt form complementary stripe structures on both sides of the electrode belt.

[0013] Optionally, it also includes: flattening the electrode strip with lithium strips coated on both sides by rolling.

[0014] Optionally, it also includes: Pre-rolling lithium strips to achieve a thickness of 1~10μm; Cut the lithium strip to match the width of the electrode strip.

[0015] This invention provides a bifacial intermittent lithium replenishment method for the negative electrode sheet of a lithium-ion battery, the advantages of which are: 1. This double-sided intermittent lithium replenishment device for the negative electrode of a lithium-ion battery utilizes a transfer bonding method to transfer lithium strips from the guide tape to the electrode tape, simultaneously replenishing lithium on both sides of the electrode tape. This allows for the production of two intermittent lithium strips using only one lithium strip splitting mechanism, facilitating simultaneous lithium replenishment on both sides of the electrode, saving on equipment investment costs and floor space. Furthermore, the alternating bonding of lithium strips on both sides provides better heat dissipation compared to continuous single-sided lithium replenishment.

[0016] 2. This bi-sided intermittent lithium replenishment method for the negative electrode of a lithium-ion battery involves staggered lithium strips on both sides of the electrode strip to replenish lithium. This ensures sufficient lithium replenishment while maintaining adequate spacing between adjacent lithium strips for heat dissipation and electrolyte filling and wetting, reducing the risk of lithium plating and improving lithium source utilization. Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0017] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0018] Figure 1 A schematic diagram of a bifacial intermittent lithium replenishment device for a lithium-ion battery negative electrode sheet according to an embodiment of the present invention is shown.

[0019] Figure 2 A schematic diagram of the guide strip of a double-sided intermittent lithium replenishment device for a lithium-ion battery negative electrode sheet according to an embodiment of the present invention is shown.

[0020] Figure 3 A schematic diagram of the electrode strip of a double-sided intermittent lithium replenishment device for a lithium-ion battery negative electrode sheet is shown according to an embodiment of the present invention.

[0021] Figure 4 A schematic diagram of the rolling mechanism of a double-sided intermittent lithium replenishment device for a lithium-ion battery negative electrode sheet according to an embodiment of the present invention is shown.

[0022] Explanation of reference numerals in the attached figures: 1. Electrode transfer assembly; 2. Lithium strip segmentation mechanism; 3. Transfer assembly; 4. Lamination assembly; 5. Guide belt; 6. Lithium strip; 7. First lithium strip feed roll; 8. Protective film feed roll; 9. Protective film take-up roll; 10. First calendering roll; 11. Second calendering roll; 12. First lithium strip unloading roll; 13. Tension roll; 14. First lithium strip take-up roll; 41. Peeling mechanism; 42. Roller pressing mechanism. Detailed Implementation

[0023] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0024] like Figure 1-4 As shown, a bifacial intermittent lithium replenishment device for a lithium-ion battery negative electrode includes: Electrode transfer assembly 1, which is used to transfer electrode strips; Lithium strip dividing mechanism 2 is used to divide lithium strip 6 into lithium strips of equal width; Two transmission components 3 are used to synchronously transmit lithium strips in conjunction with the electrode belt. The lithium strips are arranged at equal intervals on the side of the transmission component 3 close to the electrode belt. The laminating component 4 is used to laminate the lithium strips on the two transmission components 3 onto both sides of the electrode strip, so that complementary stripe structures are formed on both sides of the electrode strip.

[0025] Specifically, the lithium strips on the guide band 5 are transferred to the electrode strip using a transfer bonding method, and lithium is simultaneously applied to both sides of the electrode strip. This allows for the production of two intermittent lithium strips 6 using only one lithium strip splitting mechanism 2 (intermittent lithium strip production mechanism), facilitating simultaneous lithium application to both sides of the electrode and saving on equipment investment costs and floor space. Furthermore, the alternating bonding of lithium strips on both sides provides better heat dissipation compared to continuous lithium application on one side.

[0026] Furthermore, the width of the lithium strip is the same as the width of the electrode strip, and the length of the lithium strip is the same as the width of the electrode strip.

[0027] In this embodiment, the transmission component 3 includes a guide belt unwinding roll and a guide belt take-up roll. One end of the guide belt 5 is connected to the guide belt unwinding roll, and the other end of the guide belt 5 is connected to the guide belt take-up roll after passing through the lithium belt splitting mechanism 2 and the laminating component 4.

[0028] In this embodiment, the guide belt 5 is provided with adhesive strips at intervals to cooperate with the lithium strip, and the lithium strip splitting mechanism 2 includes: Two convex and concave rollers, which mesh with each other; The heating module is installed on the convex roller and is used to heat the raised part of the convex roller. The raised part can heat the adhesive strip to bond the lithium strip. In use, the lithium strip 6 and the guide strips 5 on both sides form a three-layer structure. The lithium strip dividing mechanism 2 divides the lithium strip 6 into multiple lithium strips, and the multiple lithium strips are alternately attached to the two guide strips 5.

[0029] Specifically, the three-layer structure passes between two meshing convex and concave rollers, using the shearing force between the rollers to divide the lithium strip 6 into lithium strips. At the same time, the lithium strips are alternately attached to the guide belts 5 on both sides, forming two complementary toothed guide belts 5. For example, odd-numbered lithium strips are assigned to one guide belt 5 at intervals, and even-numbered lithium strips are assigned to the other guide belt 5 at intervals. The two guide belts 5 form two meshing toothed rack structures.

[0030] Furthermore, the step height of the concave-convex roller is preferably 1mm to 10mm.

[0031] In this embodiment, the guide strip 5 is a polyethylene terephthalate film, and the spacing and width of the adhesive strips are consistent with the width of the lithium strip.

[0032] Specifically, a composite layer of adhesive and solid electrolyte is intermittently coated on a polyethylene terephthalate (PET) film and used as an adhesive strip. This adhesive strip is viscous at a certain temperature, preferably 90-95°C.

[0033] In this embodiment, the bonding assembly 4 includes a peeling mechanism 41 and a rolling mechanism 42. The peeling mechanism 41 is used to peel off the guide belt 5, and the rolling mechanism 42 is used to flatten the electrode strip with lithium strips bonded to both sides.

[0034] Specifically, the peeling mechanism 41 is a heating mechanism that heats the guide belt 5 from the side away from the electrode belt, causing the adhesive layer to loosen its connection with the guide belt while still maintaining a connection, facilitating the subsequent transfer of the lithium strip to the electrode belt. The rolling mechanism 42 then continuously rolls the lithium strip on the electrode belt, forming an intermittently lithium-replenished electrode belt.

[0035] like Figure 4 As shown, in this embodiment, a calendering mechanism is also included, which is used to adjust the thickness and width of the lithium strip 6.

[0036] Specifically, the thickness of the lithium strip 6 is adjusted by the calendering mechanism. With a fixed lithium strip size, the amount of lithium replenishment is adjusted by changing the thickness of the lithium strip 6. To ensure the calendering effect, multiple calendering cycles can be performed.

[0037] The present invention also provides a method for bifacial intermittent lithium replenishment of a lithium-ion battery negative electrode sheet, and a bifacial intermittent lithium replenishment device based on the above-mentioned battery negative electrode sheet, comprising: The lithium strip is divided into six equal-spaced lithium strips; The lithium strips are transmitted synchronously along two transmission paths. Multiple lithium strips are distributed at equal intervals along the two transmission paths, and the lithium strips along the two transmission paths are arranged alternately. The electrode strip is transmitted at a constant speed between the two transmission paths; The lithium strips on the two transmission paths are laminated to both sides of the electrode strip, so that complementary stripe structures are formed on both sides of the electrode strip.

[0038] Specifically, by staggering lithium strips on both sides of the electrode strip, lithium replenishment is achieved, ensuring sufficient gaps between adjacent lithium strips for heat dissipation and electrolyte filling and wetting, reducing the risk of lithium plating and improving lithium source utilization.

[0039] Furthermore, because it is a double-sided lithium-filled electrode, compared to a single-sided lithium-filled electrode, the physical properties of the double-sided lithium-filled electrode are more balanced, and the chemical reaction contact during use is more complete and balanced.

[0040] In this embodiment, bonding the lithium strips on the two transmission paths to both sides of the electrode strip includes: The primary roller-pressed guide belt 5 and the electrode belt make the lithium strip adhere to the electrode belt; Peel off the guide band 5 to separate the guide band 5 from the lithium strip on the electrode strip; The lithium strips on the rolled electrode belt form complementary stripe structures on both sides of the electrode belt.

[0041] In this embodiment, the method further includes: pressing the electrode strip with lithium strips on both sides flat by means of a rolling mechanism 42.

[0042] In this embodiment, it also includes: The lithium strip 6 is pre-rolled to a thickness of 1~10μm; Cut the lithium strip 6 to make its width match that of the electrode strip.

[0043] Specifically, the parameters of lithium strip 6 and lithium strip are set according to the parameters of the electrode strip to be repaired.

[0044] Furthermore, to ensure the calendering effect, the lithium strip 6 can be gradually thinned through multiple calendering processes. For example, it can be calendered once to 10~20μm and then calendered a second time to 1~10μm. Example

[0045] In this embodiment, a bifacial intermittent lithium replenishment device for a lithium-ion battery negative electrode is used, taking the bifacial intermittent lithium replenishment method for the lithium-ion battery negative electrode as an example: The device includes a calendering mechanism, a first transfer assembly, and a second transfer assembly; The rolling mill includes: The system comprises a first lithium strip feed roll 7, a first lithium strip take-up roll 14, two protective film feed rolls 8, two protective film take-up rolls 9, a first calendering roll 10, a second calendering roll 11, a tension roll 13, and multiple reversing rolls and transition rolls. Secondary calendering is performed via two calendering rolls. The two protective film feed rolls 8 move synchronously with the first lithium strip feed roll 7, forming a sandwich structure by clamping the lithium strip 6 between the two protective films. This protects the lithium strip 6, preventing it from sticking to the calendering rolls during calendering and ensuring a smooth and flat surface. After calendering, the protective films are wound up by the two protective film take-up rolls 9, allowing the first lithium strip take-up roll 14 to individually wind up the lithium strip 6.

[0046] Second lithium strip feed roll and second lithium strip take-up roll; The lithium strip dividing mechanism 2 is used to divide the lithium strip 6 into lithium strips of equal width. The lithium strip dividing mechanism 2 includes two concave and convex rollers and a heating module for heating the protrusions of the concave and convex rollers. Two transmission components 3 are used to convey guide belts 5. The guide belts 5 are provided with adhesive strips for bonding lithium strips on the side near the lithium strip 6. The transmission components 3 include a guide belt feeding roll, a guide belt take-up roll, and a diversion and reversing mechanism. The diversion and reversing mechanism is used to adjust the tension and direction of the guide belts 5 and guide the two guide belts 5 to approach the two sides of the electrode strip respectively. The diversion and reversing mechanism includes multiple reversing rollers and multiple tensioning rollers. Electrode transfer assembly 1 includes an electrode feed roll and an electrode take-up roll; The laminating assembly 4 is used to transfer the lithium strip on the guide belt 5 to the electrode belt. The laminating assembly 4 includes a peeling mechanism 41 and a rolling mechanism 42. The peeling mechanism 41 is used to peel off the guide belt 5, and the rolling mechanism 42 is used to flatten the electrode belt with lithium strips laminated on both sides.

[0047] To ensure the stable operation of each mechanism, the rotation speed of each mechanism is controlled independently and monitored by sensors (speed sensor, rotation speed sensor, temperature sensor, etc.) to ensure coordinated operation.

[0048] The protective film is a polyethylene terephthalate film; The guide band 5 is a polyethylene terephthalate film, with an intermittently coated composite layer of adhesive and solid electrolyte as the adhesive strip.

[0049] Method and Flow: First, lithium strip 6 is rolled. Lithium strip 6 is rolled once to 26.5 μm, and then rolled a second time to 2.5 μm. The rolled lithium strip 6 is installed onto the second lithium strip feed roll, and the electrode strip roll is installed on the electrode feed roll. The guide belt 5 is installed on the transmission assembly 3. The guide belt 5 and the lithium belt 6 form a three-layer structure and pass through the space between two concave and convex rollers. The lithium belt 6 is divided into lithium strips by the shearing force between the rollers. At the same time, the lithium strips are alternately attached to the guide belts 5 on both sides to form two complementary toothed guide belts 5. After passing through the diversion mechanism, the two guide belts 5 form a three-layer structure with the electrode belt. The lithium strip is then alternately bonded to both sides of the electrode belt using the composite component 4.

[0050] The laminating assembly 4 first uses the peeling mechanism 41 to heat the guide belt 5 with lithium strips, loosening the connection between the lithium strips and the guide belt 5. Then, the rolling mechanism 42 continuously rolls the lithium strips on the electrode belt, forming an intermittently lithium-replenished electrode belt. Because the lithium strips and the electrode belt are integrated after rolling, the winding guide belt 2 simultaneously separates the guide belt and the lithium strips, transferring the lithium strips from the guide belt 5 to the electrode belt.

[0051] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A double-sided intermittent lithium replenishment device for a lithium-ion battery negative electrode sheet, characterized in that, include: An electrode transport assembly, wherein the electrode transport assembly is used to transport electrode strips; A lithium strip dividing mechanism is used to divide a lithium strip into lithium strips of equal width. Two transmission components are provided, which are used to synchronously transmit lithium strips in conjunction with the electrode strip. The lithium strips are arranged at equal intervals on the side of the transmission components near the electrode strip. A laminating assembly is used to laminate lithium strips from the two transmission assemblies onto both sides of the electrode strip, so that complementary stripe structures are formed on both sides of the electrode strip.

2. The double-sided intermittent lithium replenishment device for the negative electrode sheet of a lithium-ion battery according to claim 1, characterized in that, The transmission component includes a guide belt unwinding roll and a guide belt take-up roll. One end of the guide belt is connected to the guide belt unwinding roll, and the other end of the guide belt is connected to the guide belt take-up roll after passing through the lithium strip splitting mechanism and the laminating component.

3. The double-sided intermittent lithium replenishment device for the negative electrode sheet of a lithium-ion battery according to claim 2, characterized in that, The guide belt is spaced with adhesive strips that mate with the lithium strip. The lithium strip splitting mechanism includes: Two convex and concave rollers, the two convex and concave rollers meshing with each other; A heating module is disposed on the convex roller and is used to heat the protruding part of the convex roller. The protruding part can heat the adhesive strip to bond the lithium strip. In use, the lithium strip and the guide strips on both sides form a three-layer structure. The lithium strip dividing mechanism divides the lithium strip into multiple lithium strips, and the multiple lithium strips are alternately attached to the two guide strips.

4. The double-sided intermittent lithium replenishment device for the negative electrode sheet of a lithium-ion battery according to claim 3, characterized in that, The guide strip is made of polyethylene terephthalate film, and the spacing and width of the adhesive strip are consistent with the width of the lithium strip.

5. The double-sided intermittent lithium replenishment device for the negative electrode sheet of a lithium-ion battery according to claim 1, characterized in that, The lamination assembly includes a peeling mechanism and a rolling mechanism. The peeling mechanism is used to peel off the guide strip, and the rolling mechanism is used to flatten the electrode strip with lithium strips laminated on both sides.

6. The double-sided intermittent lithium replenishment device for the negative electrode sheet of a lithium-ion battery according to claim 1, characterized in that, It also includes a calendering mechanism for adjusting the thickness and width of the lithium strip.

7. A method for bifacial intermittent lithium replenishment of a lithium-ion battery negative electrode, based on the bifacial intermittent lithium replenishment device for the battery negative electrode according to any one of claims 1-6, characterized in that, include: The lithium strip is divided into lithium strips at equal intervals; The lithium strips are transmitted synchronously along two transmission paths. Multiple lithium strips are distributed at equal intervals along the two transmission paths, and the lithium strips along the two transmission paths are arranged alternately. The electrode strip is transmitted at a constant speed between the two transmission paths; The lithium strips on the two transmission paths are laminated to both sides of the electrode strip, so that complementary stripe structures are formed on both sides of the electrode strip.

8. The method for bifacial intermittent lithium replenishment of the negative electrode sheet of a lithium-ion battery according to claim 7, characterized in that, The process of bonding lithium strips on the two transmission paths to both sides of the electrode strip includes: The primary roll-formed guide belt and electrode belt bond the lithium strip to the electrode belt; Peel off the guide strip to separate it from the lithium strip on the electrode strip; The lithium strips on the rolled electrode belt form complementary stripe structures on both sides of the electrode belt.

9. The method for intermittent lithium replenishment on both sides of the negative electrode sheet of a lithium-ion battery according to claim 7, characterized in that, Also includes: The electrode strip with lithium strips on both sides is flattened by rolling.

10. The method for bifacial intermittent lithium replenishment of the negative electrode sheet of a lithium-ion battery according to claim 7, characterized in that, Also includes: Pre-rolling lithium strips to achieve a thickness of 1~10μm; Cut the lithium strip to match the width of the electrode strip.

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