Negative electrode coating process for reducing internal resistance of battery

Abstract

The invention discloses a negative electrode coating process for reducing internal resistance of a battery, and relates to the technical field of batteries, and the negative electrode coating process comprises the following steps: step 1, coating a continuously fed foil with negative electrode slurry according to the following requirements: 1) reserving a coating gap I on the foil along the feeding direction of the foil; (2) a second coating gap is reserved in the foil in the width direction of the foil; and secondly, the foil coated in the first step is rolled. According to the coating structure, the first coating gap and the second coating gap are reserved at the coating position of the foil, then the coated foil is cut into the negative plate with the exposed foil on one side through the cutting device, and therefore after the negative plate is wound, conduction can be achieved by making contact with the shell together through the negative tab and the copper foil, and the negative plate can be connected with the shell through the negative tab and the copper foil. According to the coating process, the contact resistance of the lithium ion battery is greatly reduced, so that the internal resistance of the lithium ion battery is reduced, a traditional coating process is replaced by the coating process, and the internal resistance of the lithium ion battery is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a negative electrode coating process for reducing the internal resistance of a battery. Background Art

[0002] In recent years, with the rise of the power tool market and the expansion of the application market, the requirements for lithium batteries are getting higher and higher. At present, the traditional battery process structure is a tab contact type, with 2 tabs on the positive electrode and 2 tabs on the negative electrode or 3 tabs on the positive electrode and 3 tabs on the negative electrode. The internal resistance of the positive and negative tabs is between 10-12mΩ, and the internal resistance of the positive and negative tabs is 8-10mΩ. This type of battery has a high internal resistance, a large temperature rise during battery charging and discharging, a low charge and discharge rate of lithium-ion batteries, low production efficiency, and a low production qualification rate. Summary of the invention

[0003] The object of the present invention is to provide a negative electrode coating process for reducing the internal resistance of a battery, so as to solve the problems raised in the above background technology.

[0004] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme: The present invention provides a negative electrode coating process for reducing the internal resistance of a battery, characterized in that it comprises the following steps: Step 1: Apply the negative electrode slurry to the continuously fed foil according to the following requirements: 3) Leave a coating gap of - on the foil along the foil feeding direction; 4) Leave a coating gap of two on the foil along the width direction of the foil; Step 2: Rolling the foil coated in step 1; Step 3: The foil rolled in step 2 is cut into a plurality of negative electrode sheets by a cutting device according to the following requirements: 1) Cutting along the second gap of the foil so that one side of the negative electrode sheet has exposed foil; Step 4: Weld the pole ear at a position of the coating gap reserved for the negative electrode sheet; Step 5: Wind the negative electrode sheet in step 4. When winding, fold the tabs first and then flatten the exposed foil. After completion, shell it.

[0005] Furthermore, the coating gap 1 is 10±0.5 mm, and the coating gap 2 is 6±0.5 mm.

[0006] Furthermore, the length of the coating area in the adjacent coating gap 1 of the negative electrode sheet is 1271.5±0.5 mm, and the width of the coating area is 122±0.5 mm.

[0007] Furthermore, the slitting device used in step three includes a frame, an unwinding mechanism installed at one end of the frame, a reeling mechanism installed at the other end of the frame, and a slitting mechanism installed on the frame between the reeling mechanism and the unwinding mechanism; the slitting mechanism includes an upper knife shaft and a lower knife shaft horizontally rotatably arranged on the frame, a plurality of upper disc knives mounted on the upper knife shaft, and a plurality of lower disc knives mounted on the lower knife shaft, wherein the corresponding upper disc knives and lower disc knives constitute a disc knife group, and the upper knife shaft and the lower knife shaft rotate towards each other under the drive of the driving device; The upper blade shaft and the lower blade shaft have the same structure, both comprising a rotating cylinder and end covers detachably fixedly mounted on both ends of the rotating cylinder, a convex shaft is coaxially arranged at one end of the end cover away from the rotating cylinder, and strip-shaped adjustment grooves extending along the length direction are symmetrically penetrated on the side wall of the rotating cylinder; a spacing adjustment component for adjusting the spacing between a plurality of disc blade groups is installed in the rotating cylinder.

[0008] Furthermore, the spacing adjustment assembly includes a central rotating shaft coaxially arranged in the rotating cylinder, an equidistant adjustment component arranged outside the central rotating shaft, and a locker for locking the central rotating shaft. The central rotating shaft can drive the equidistant adjustment component to complete the equidistant adjustment of the disc knife group by rotating.

[0009] Further, the equidistant adjustment component comprises a scissor-type telescopic frame symmetrically arranged on both sides of the central rotating shaft, the scissor-type telescopic frame comprises a middle hinge node and side hinge nodes symmetrically arranged on both sides of the middle hinge node, a first connecting rod is arranged between the side hinge nodes corresponding to a pair of scissor-type telescopic frames, and a second connecting rod extending into the corresponding strip-shaped adjustment groove is arranged on the opposite sides of the middle hinge nodes of the pair of scissor-type telescopic frames, and the second connecting rod is fixedly connected to a mounting block slidably adapted in the strip-shaped adjustment groove at one end away from the scissor-type telescopic frame; Two middle hinged nodes at one end of a pair of scissor-type telescopic frames are connected to a first driving block via a third connecting rod, and two middle hinged nodes at the other end of the pair of scissor-type telescopic frames are connected to a second driving block via a third connecting rod; The central rotating shaft is provided with a transmission structure, and the transmission structure is used to drive the first driving block and the second driving block to move toward or away from each other along the axial direction of the rotating cylinder when the central rotating shaft rotates; The upper disc knife of the upper knife shaft is fixedly connected to two corresponding mounting blocks in a pair of strip-shaped adjustment grooves by bolts, and the lower disc knife of the lower knife shaft is fixedly connected to two corresponding mounting blocks in a pair of strip-shaped adjustment grooves by bolts.

[0010] Furthermore, the end covers at both ends of the rotating cylinder are respectively a first end cover and a second end cover, wherein the first end cover is penetrated by a through hole; The central rotating shaft is coaxially rotatably assembled in the rotating cylinder, the central rotating shaft includes a rotating shaft and a rotating sleeve, the rotating shaft includes a first rotating part with one end rotatably connected to the second end cover through a bearing seat, and a second rotating part coaxially connected to the first rotating part at one end away from the second end cover, the end of the second rotating part away from the first rotating part passes through the through hole of the first end cover and is fixedly assembled with a first gear, the rotating sleeve is rotatably sleeved on the outside of the second rotating part, the rotating sleeve is rotatably connected to the first end cover through the bearing seat, the end of the rotating sleeve close to the first rotating part contacts the end of the first rotating part, and the end of the rotating sleeve away from the first rotating part passes through the through hole of the first end cover and is fixedly assembled with a second gear; A first transmission tooth meshing with the first gear is provided on one side of the first gear via a rotating support, and a second transmission tooth meshing with the second gear is provided on one side of the second gear via a rotating support; wherein the input shaft of the first transmission tooth is connected to the first regulating motor via a clutch transmission, and the input shaft of the second transmission tooth is connected to the second regulating motor via a clutch transmission; The transmission structure includes a third thread arranged on the first rotating part and a fourth thread arranged on the rotating sleeve, the third thread cooperates with the first driving block thread, the fourth thread cooperates with the second driving block thread, and the pitch parameters of the third thread and the fourth thread are the same.

[0011] Compared with the prior art, one or more of the above technical solutions have the following beneficial effects: (1) The present invention coats the foil material with a coating structure leaving coating gap 1 and coating gap 2, and then uses a slitting device to slit the coated foil material into negative electrode sheets with exposed foil material on one side. Thus, after the negative electrode sheet is wound, the negative electrode tab and the copper foil can be contacted with the shell together to achieve conduction, which greatly reduces the contact impedance of the lithium-ion battery, thereby reducing the internal resistance of the lithium-ion battery. The coating process of the present invention replaces the traditional coating process and greatly reduces the internal resistance of the lithium-ion battery.

[0012] (2) The present invention can not only quickly and equidistantly adjust the gap between adjacent disc cutter groups to adapt to the rapid cutting of pole pieces of different sizes without affecting the normal rotation of the upper cutter shaft and the lower cutter shaft, but also flexibly adjust the positions of the upper disc cutter and the lower disc cutter to maintain a suitable lateral extrusion pressure between the upper disc cutter and the lower disc cutter according to the material being cut, thereby improving the cutting quality.

[0013] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0015] Figure 1 It is a schematic diagram of coating the sizing material on the foil of the present invention; Figure 2 It is a schematic diagram of the sizing material coating structure of the negative electrode plate of the present invention; Figure 3 It is a schematic structural diagram of a slitting device of the present invention; Figure 4 It is a schematic diagram of the structure of the slitting mechanism of the present invention; Figure 5 It is a schematic diagram of the upper cutter shaft structure of the present invention; Figure 6 It is a schematic diagram of the cross-sectional plan structure of the upper cutter shaft of the present invention; Figure 7 It is a schematic diagram of the structure of the spacing adjustment component of the present invention; Figure 8 yes Figure 7 Schematic diagram of the local structure at A; Fig. 9 It is a schematic structural diagram of the connection between the first driving block and a pair of scissor-type telescopic frames of the present invention; Fig.10 yes Figure 7 Schematic diagram of the front view structure Fig.11 It is a schematic diagram of the structure of the isometric adjustment component of the present invention; Fig.12 It is a schematic diagram of the three-dimensional structure of the upper cutter shaft of the present invention; Fig.13 It is a schematic diagram of the central rotating shaft structure of the present invention.

[0016] In the figure: 1-foil; 11-coating gap 1; 12-coating gap 2; 2-slitting device; 21-frame; 22-rewinding mechanism; 23-unwinding mechanism; 24-slitting mechanism; 3-upper knife shaft; 4-lower knife shaft; 5-disc knife group; 51-upper disc knife; 52-lower disc knife; 6-rotating cylinder; 61-end cover; 611-first end cover; 6111-through hole; 612-second end cover; 62-convex shaft; 63-strip adjustment groove; 7-spacing adjustment component; 71-central rotating shaft; 711-rotating shaft; 7111-first rotating part; 7112-second rotating part; 712- Rotating sleeve; 72-equidistant adjustment component; 721-scissor-type telescopic frame; 7211-middle hinge node; 7212-side hinge node; 722-first connecting rod; 723-second connecting rod; 724-mounting block; 725-third connecting rod; 726-first drive block; 727-second drive block; 733-third thread; 734-fourth thread; 81-first gear; 82-second gear; 83-first transmission tooth; 84-second transmission tooth; 85-clutch; 86-first adjusting motor; 87-second adjusting motor; 9-locking device; 91-locking bolt. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0018] The present invention provides a negative electrode coating process for reducing the internal resistance of a battery, comprising the following steps: Step 1: Apply the negative electrode slurry onto the continuously fed foil 1 (such as Figure 1 shown): 1) leaving a coating gap 11 on the foil 1 along the feeding direction of the foil 1; 2) leaving a coating gap 12 on the foil 1 along the width direction of the foil 1; Step 2: rolling the foil material 1 coated in step 1; Step 3: The foil material 1 rolled in step 2 is cut into a plurality of negative electrode sheets by a cutting device 2 according to the following requirements: 1) Cut along the gap 2 of the foil 1 so that one side of the negative electrode sheet has exposed foil 1 (such as Figure 2 shown); Step 4: Weld the pole ear at the coating gap 11 position reserved for the negative electrode sheet; Step 5: Wind the negative electrode sheet in step 4, fold the tabs first and then flatten the exposed foil 1, and then pack it into a shell.

[0019] like Figure 1 As shown, in this embodiment, the coating gap 11 is 10±0.5 mm, and the coating gap 2 12 is 6±0.5 mm.

[0020] like Figure 1 As shown, in this embodiment, the length of the coating area in the adjacent coating gap 11 of the negative electrode sheet is 1271.5±0.5 mm, and the width of the coating area is 122±0.5 mm.

[0021] The present invention coats a coating structure with a coating gap 11 and a coating gap 2 12 on the foil 1, and then cuts the coated foil 1 into negative electrode sheets with the foil 1 exposed on one side by a slitting device 2. Therefore, after the negative electrode sheet is wound, conduction can be achieved by the negative electrode tab and the copper foil contacting the shell together, which greatly reduces the contact impedance of the lithium ion battery, thereby reducing the internal resistance of the lithium ion battery.

[0022] like Figure 3 As shown, in this embodiment, the slitting device 2 used in step three includes a frame 21, an unwinding mechanism 23 installed at one end of the frame 21, a rewinding mechanism 22 installed at the other end of the frame 21, and a slitting mechanism 24 installed on the frame 21 between the rewinding mechanism 22 and the unwinding mechanism 23.

[0023] like Figure 4 As shown, the slitting mechanism 24 includes an upper knife shaft 3 and a lower knife shaft 4 horizontally rotatably arranged on the frame 21, a plurality of upper disc knives 51 mounted on the upper knife shaft 3, and a plurality of lower disc knives 52 mounted on the lower knife shaft 4, wherein the corresponding upper disc knives 51 and lower disc knives 52 are grouped into a disc knife group 5, and the upper knife shaft 3 and the lower knife shaft 4 rotate towards each other under the drive of the driving device.

[0024] like Figure 1 and Figure 2As shown, when in use, the unwinding mechanism 23 releases the rolled foil 1. When the foil 1 passes through the slitting mechanism 24, the plurality of disc knife groups 5 mounted on the upper knife shaft 3 and the lower knife shaft 4 can slit the foil 1 into a plurality of negative electrode sheets during the process of the upper knife shaft 3 and the lower knife shaft 4 rotating toward each other, that is, the upper knife shaft 3 and the lower knife shaft 4 respectively drive the upper disc knife 51 and the lower disc knife 52 to rotate toward each other, and the slitting of the foil 1 is completed by the cooperation of the rotating upper disc knife 51 and the rotating lower disc knife 52, and then the slit negative electrode sheets are rolled up by the winding mechanism 22. The winding mechanism 22, the unwinding mechanism 23 and the driving device are all prior arts. Their specific structures and specific winding and unwinding principles, as well as the principle of how to drive the upper knife shaft 3 and the lower knife shaft 4 to rotate toward each other will not be elaborated here.

[0025] like Figure 5 and Figure 6 As shown, further, the upper cutter shaft 3 and the lower cutter shaft 4 have the same structure, both of which include a rotating cylinder 6 and end covers 61 detachably fixedly mounted at both ends of the rotating cylinder 6, a convex shaft 62 is coaxially arranged at one end of the end cover 61 away from the rotating cylinder 6, and strip-shaped adjustment grooves 63 extending along the length direction are symmetrically penetrated on the side wall of the rotating cylinder 6; a spacing adjustment component 7 for adjusting the spacing between a plurality of disc cutter groups 5 is installed in the rotating cylinder 6.

[0026] The upper knife shaft 3 and the lower knife shaft 4 are rotatably mounted on the frame 21 through the convex shafts 62 at both ends thereof, and one of the convex shafts of the upper knife shaft 3 and the lower knife shaft 4 is transmission-connected to the driving device. Before slitting, the present invention can adaptively adjust the positions of the upper disc knife 51 and the lower disc knife 52 according to the size of the coating structure of the foil 1 through the spacing adjustment component 7 inside the upper knife shaft 3 and the lower knife shaft 4, so as to quickly complete the slitting work.

[0027] like Figure 6 As shown, in this embodiment, the spacing adjustment assembly 7 includes a central rotating shaft 71 coaxially arranged in the rotating cylinder 6, an equidistant adjustment component 72 arranged outside the central rotating shaft 71, and a locker 9 for locking the central rotating shaft 71. The central rotating shaft 71 can drive the equidistant adjustment component 72 to complete the equidistant adjustment of the disc knife group 5 by rotating.

[0028] When the foil 1 is cut, the locker 9 is used to lock the central shaft 71, so that the central shaft 71 and the rotating cylinder 6 remain relatively still, so as to avoid relative rotation between the central shaft 71 and the rotating cylinder 6, which would cause displacement of the disc cutter group 5; and when adjusting the gap between several disc cutter groups 5, the locker 9 can release the lock on the central shaft 71, so that the central shaft 71 can rotate in the rotating cylinder 6, so as to drive the equidistant adjustment component 72 to complete the equidistant adjustment of several disc cutter groups 5.

[0029] like Figure 6-Figure 8As shown, in this embodiment, the equidistant adjustment component 72 includes a scissor-type telescopic frame 721 symmetrically arranged on both sides of the central rotation axis 71, and the scissor-type telescopic frame 721 includes a middle hinge node 7211 and side hinge nodes 7212 symmetrically arranged on both sides of the middle hinge node 7211, and a first connecting rod 722 is arranged between the side hinge nodes 7212 corresponding to a pair of scissor-type telescopic frames 721, and a second connecting rod 723 extending into the corresponding strip-shaped adjustment groove 63 is arranged on the opposite side of the middle hinge node 7211 of the pair of scissor-type telescopic frames 721, and the second connecting rod 723 is fixedly connected to the end away from the scissor-type telescopic frame 721 with a mounting block 724 slidably adapted in the strip-shaped adjustment groove 63; Combination Fig. 9 As shown, two middle hinged nodes 7211 at one end of a pair of scissor-type telescopic frames 721 are connected to a first driving block 726 through a third connecting rod 725, and two middle hinged nodes 7211 at the other end of the pair of scissor-type telescopic frames 721 are connected to a second driving block 727 through the third connecting rod 725 in the same way; The central rotating shaft 71 is provided with a transmission structure, and the transmission structure is used to drive the first driving block 726 and the second driving block 727 to move along the axial direction of the rotating cylinder 6 when the central rotating shaft 71 rotates; The upper disc knife 51 of the upper knife shaft 3 is fixedly connected to the two corresponding mounting blocks 724 in a pair of strip-shaped adjustment grooves 63 by bolts, and the lower disc knife 52 of the lower knife shaft 4 is fixedly connected to the two corresponding mounting blocks 724 in a pair of strip-shaped adjustment grooves 63 by bolts.

[0030] Combination Figure 8 and Figure 7 As shown, a space mesh structure is formed by setting a first connecting rod 722 between the side hinge nodes 7212 corresponding to a pair of scissor-type telescopic frames 721, and the structure can stably adjust the distance between adjacent disc knife groups 5.

[0031] During the slitting process, the user can adaptively install a suitable number of upper disc knives 51 and lower disc knives 52 on the upper knife shaft 3 and the lower knife shaft 4 according to the needs. During installation, the knife seats of the upper disc knives 51 and the lower disc knives 52 can be fixedly connected with the corresponding mounting blocks 724 in a pair of strip-shaped adjustment grooves 63 respectively. When it is necessary to adjust the spacing between adjacent disc knife groups 5, the lock of the central rotating shaft is released by the locker 9, and the central rotating shaft 71 is rotated. The central rotating shaft 71 can drive the first driving block 726 and the second driving block 727 to move along the axial direction of the rotating cylinder 6 through the transmission structure; When the first driving block 726 and the second driving block 727 move, the two ends of the scissors-type telescopic frame 721 move, and the length of the scissors-type telescopic frame 721 can be shortened or increased accordingly. During this process, the distance between adjacent middle hinged nodes 7211 will be correspondingly reduced or increased synchronously, thereby quickly completing the equidistant adjustment of the distance between adjacent disc knife groups 5.

[0032] like Figure 6 As shown, in this embodiment, the end covers 61 at both ends of the rotating cylinder 6 are respectively a first end cover 611 and a second end cover 612, wherein the first end cover 611 is penetrated by a through hole 6111; like Figure 6 , Figure 7 and Fig.11 As shown, the central rotating shaft 71 is coaxially rotatably assembled in the rotating cylinder 6, and the central rotating shaft 71 includes a rotating shaft 711 and a rotating sleeve 712 (as shown in FIG. Fig.13 As shown in the figure, the rotating shaft 711 includes a first rotating part 7111 whose one end is rotatably connected to the second end cover 612 through a bearing seat, and a second rotating part 7112 coaxially connected to an end of the first rotating part 7111 away from the second end cover 612, the end of the second rotating part 7112 away from the first rotating part 7111 passes through the through hole 6111 of the first end cover 611 and is fixedly equipped with the first gear 81, the rotating sleeve 712 is rotatably arranged on the outside of the second rotating part 7112, the rotating sleeve 712 is rotatably connected to the first end cover 611 through the bearing seat, the end of the rotating sleeve 712 close to the first rotating part 7111 contacts the end of the first rotating part 7111, and the end of the rotating sleeve 712 away from the first rotating part 7111 passes through the through hole 6111 of the first end cover 611 and is fixedly equipped with the second gear 82; A first transmission tooth 83 meshing with the first gear 81 is provided on one side of the first gear 81 through a rotating support, and a second transmission tooth 84 meshing with the second gear 82 is provided on one side of the second gear 82 through a rotating support; wherein the input shaft of the first transmission tooth 83 is connected to a first regulating motor 86 through a clutch 85, and the input shaft of the second transmission tooth 84 is connected to a second regulating motor 87 through a clutch 85; The transmission structure includes a third thread 733 arranged on the first rotating part 7111, and a fourth thread 734 arranged on the rotating sleeve 712, the third thread 733 is threadedly matched with the first driving block 726, the fourth thread 734 is threadedly matched with the second driving block 727, and the pitch and other parameters of the third thread 733 and the fourth thread 734 are the same.

[0033] The locker 9 includes a locking bolt 91 that is arranged through the first end cover 611 and the second end cover 612. Fig.12As shown, the user can rotate the locking bolts 91 on the first end cover 611 and the second end cover 612 to make the two locking bolts 91 respectively interfere with the first rotating part 7111 and the rotating sleeve 712 to lock the rotation of the central rotating shaft 71 (i.e., the rotating shaft 711 and the rotating sleeve 712) to avoid relative rotation between the rotating shaft 711, the rotating sleeve 712 and the rotating cylinder 6, resulting in displacement of the disc knife group 5.

[0034] Based on the above design, the present invention can not only quickly and equidistantly adjust the gap between adjacent disc knife groups 5 to adapt to the rapid cutting of negative electrode sheets of different sizes without affecting the normal rotation of the upper knife shaft 3 and the lower knife shaft 4, but also flexibly adjust the positions of the upper disc knife 51 and the lower disc knife 52 to maintain a suitable lateral extrusion pressure between the upper disc knife 51 and the lower disc knife 52 according to the cutting material, thereby improving the cutting quality.

[0035] Specifically, when the foil 1 is cut, the central rotating shaft 71 (i.e., the rotating shaft 711 and the rotating sleeve 712) and the rotating drum 6 remain relatively stationary and rotate together with the rotating drum 6. During this process, the first gear 81 and the second gear 82 fixedly mounted on the rotating shaft 711 and the rotating sleeve 712 rotate, and the first transmission tooth 83 and the second transmission tooth 84 rotate accordingly, but the clutch 85 is in a non-linked state, and the synchronization between the first transmission tooth 83, the second transmission tooth 84 and the output shaft of each motor is interrupted; When the position of the disc knife group 5 needs to be adjusted (the following description is the synchronous adjustment of the upper disc knife 51 and the lower disc knife 52), the clutch 85 is put into a linkage state. In this state, there are multiple options, specifically: 1) The first adjusting motor 86 can be started, so that the first adjusting motor 86 rotates to drive the first transmission gear 83 to rotate, and then the rotating rod is driven to rotate through the first gear 81. At this time, the first driving block 726 is in a stationary state, and the second driving block 727 moves. When the second driving block 727 moves to the left, several disc knife groups 5 all move to the left, and the gaps between adjacent disc knife groups 5 are synchronously reduced. When the second driving block 727 moves to the right, several disc knife groups 5 all move to the right, and the gaps between adjacent disc knife groups 5 are synchronously increased.

[0036] 2) The second adjusting motor 87 can be started to rotate and drive the second transmission gear 84 to rotate, and then drive the rotating sleeve 712 to rotate through the second gear 82. At this time, the second driving block 727 is in a stationary state, and the first driving block 726 moves. When the second driving block 727 moves to the left, several disc knife groups 5 all move to the left, and the gaps between adjacent disc knife groups 5 increase synchronously. When the second driving block 727 moves to the right, several disc knife groups 5 all move to the right, and the gaps between adjacent disc knife groups 5 decrease synchronously.

[0037] 3) The first adjustment motor 86 and the second adjustment motor 87 can be started to rotate the rotating rod and the rotating sleeve 712. At this time, the first driving block 726 and the second driving block 727 both move. When the first driving block 726 and the second driving block 727 move toward each other, the plurality of disc knife groups 5 all move in the middle, and the gaps between adjacent disc knife groups 5 are synchronously reduced; when the first driving block 726 and the second driving block 727 move away from each other, the plurality of disc knife groups 5 move symmetrically toward both ends, and the gaps between adjacent disc knife groups 5 are synchronously increased; when the first driving block 726 and the second driving block 727 both move toward the left side and the moving speeds are the same, the plurality of disc knife groups 5 move toward the left side as a whole without changing the spacing; when the first driving block 726 and the second driving block 727 both move toward the right side and the moving speeds are the same, the plurality of disc knife groups 5 move toward the right side as a whole without changing the spacing.

[0038] When the lateral extrusion force between the upper disc knife 51 and the lower disc knife 52 needs to be adjusted, the lateral extrusion force between the upper disc knife 51 and the lower disc knife 52 can be changed by starting the first adjustment motor 86 and the second adjustment motor 87 to move the upper disc knife 51 or the lower disc knife 52 as a whole.

[0039] It should be supplemented that, when the slitting device is slitting the pole pieces, there is no horizontal gap between the upper disc knife 51 and the lower disc knife 52. Instead, the upper disc knife 51 and the lower disc knife 52 are in contact with each other and there is lateral pressure. The lateral pressure is small, which will cause metal burrs to appear on the edge of the sheared pole piece. The metal burrs are extremely harmful to the battery. The larger metal burrs directly pierce the diaphragm, causing a short circuit between the positive and negative electrodes. The larger lateral pressure will cause serious wear of the interacting upper disc knife 51 and the lower disc knife 52, thereby shortening the service life of the upper disc knife 51 and the lower disc knife 52.

[0040] Through the above-mentioned design, the present invention can quickly adjust the lateral extrusion force of the upper disc knife 51 and the lower disc knife 52 while ensuring flexible adjustment of the gaps between the plurality of disc knife groups 5, thereby effectively extending the service life of the upper disc knife 51 and the lower disc knife 52 without affecting the slitting quality.

[0041] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A negative electrode coating process for reducing the internal resistance of a battery, characterized in that: The steps include: Step 1: Apply the negative electrode slurry to the continuously fed foil according to the following requirements: A coating gap of one is left on the foil along the foil feeding direction; A coating gap of two is left on the foil along the width direction of the foil; Step 2: Rolling the foil coated in step 1; Step 3: The foil rolled in step 2 is cut into a plurality of negative electrode sheets by a cutting device according to the following requirements: 1) Cutting along the second gap of the foil so that one side of the negative electrode sheet has exposed foil; Step 4: Weld the pole ear at a position of the coating gap reserved for the negative electrode sheet; Step 5: Wind the negative electrode sheet in step 4. When winding, fold the tabs first and then flatten the exposed foil. After completion, shell it.

2. The negative electrode coating process for reducing battery internal resistance according to claim 1, characterized in that: The coating gap 1 is 10±0.5 mm, and the coating gap 2 is 6±0.5 mm.

3. The negative electrode coating process for reducing battery internal resistance according to claim 1, characterized in that: The length of the coating area in the adjacent coating gap 1 of the negative electrode sheet is 1271.5±0.5 mm, and the width of the coating area is 122±0.5 mm.

4. According to the negative electrode coating process for reducing the internal resistance of the battery according to claim 1, the slitting device used in step 3 includes a frame, a reeling mechanism installed at one end of the frame, a reeling mechanism installed at the other end of the frame, and a slitting mechanism installed on the frame between the reeling mechanism and the unreeling mechanism; the slitting mechanism includes an upper knife shaft and a lower knife shaft horizontally rotatably arranged on the frame, a plurality of upper disc knives mounted on the upper knife shaft, and a plurality of lower disc knives mounted on the lower knife shaft, wherein, The corresponding upper disc cutter and lower disc cutter form a disc cutter group, and the upper cutter shaft and the lower cutter shaft rotate towards each other under the drive of the driving device; It is characterized in that the upper blade shaft and the lower blade shaft have the same structure, both of which include a rotating cylinder and end covers detachably fixedly mounted on both ends of the rotating cylinder, a convex shaft is coaxially arranged at one end of the end cover away from the rotating cylinder, and strip-shaped adjustment grooves extending along the length direction are symmetrically penetrated on the side wall of the rotating cylinder; a spacing adjustment component for adjusting the spacing between a plurality of disc knife groups is installed in the rotating cylinder.

5. The negative electrode coating process for reducing battery internal resistance according to claim 4, characterized in that: The spacing adjustment assembly includes a central rotating shaft coaxially arranged in the rotating cylinder, an equidistant adjustment component arranged outside the central rotating shaft, and a locker for locking the central rotating shaft. The central rotating shaft can drive the equidistant adjustment component to complete the equidistant adjustment of the disc knife group by rotating.

6. The negative electrode coating process for reducing battery internal resistance according to claim 5, characterized in that: The equidistant adjustment component includes a scissor-type telescopic frame symmetrically arranged on both sides of the central rotating shaft, the scissor-type telescopic frame includes a middle hinge node and side hinge nodes symmetrically arranged on both sides of the middle hinge node, a first connecting rod is arranged between the side hinge nodes corresponding to a pair of scissor-type telescopic frames, and a second connecting rod extending into the corresponding strip-shaped adjustment groove is arranged on the opposite sides of the middle hinge nodes of the pair of scissor-type telescopic frames, and the second connecting rod is fixedly connected to a mounting block slidably adapted in the strip-shaped adjustment groove at one end away from the scissor-type telescopic frame; Two middle hinged nodes at one end of a pair of scissor-type telescopic frames are connected to a first driving block via a third connecting rod, and two middle hinged nodes at the other end of the pair of scissor-type telescopic frames are connected to a second driving block via a third connecting rod; The central shaft is provided with a transmission structure, and the transmission structure is used to drive the first driving block and the second driving block to move toward or away from each other along the axial direction of the rotating cylinder when the central shaft rotates; The upper disc knife of the upper knife shaft is fixedly connected to two corresponding mounting blocks in a pair of strip-shaped adjustment grooves by bolts, and the lower disc knife of the lower knife shaft is fixedly connected to two corresponding mounting blocks in a pair of strip-shaped adjustment grooves by bolts.

7. The negative electrode coating process for reducing battery internal resistance according to claim 6, characterized in that: The end covers at both ends of the rotating cylinder are respectively a first end cover and a second end cover, wherein the first end cover is penetrated by a through hole; The central rotating shaft is coaxially rotatably assembled in the rotating cylinder, the central rotating shaft includes a rotating shaft and a rotating sleeve, the rotating shaft includes a first rotating part with one end rotatably connected to the second end cover through a bearing seat, and a second rotating part coaxially connected to the first rotating part at one end away from the second end cover, the end of the second rotating part away from the first rotating part passes through the through hole of the first end cover and is fixedly assembled with a first gear, the rotating sleeve is rotatably sleeved on the outside of the second rotating part, the rotating sleeve is rotatably connected to the first end cover through the bearing seat, the end of the rotating sleeve close to the first rotating part contacts the end of the first rotating part, and the end of the rotating sleeve away from the first rotating part passes through the through hole of the first end cover and is fixedly assembled with a second gear; A first transmission tooth meshing with the first gear is provided on one side of the first gear via a rotating support, and a second transmission tooth meshing with the second gear is provided on one side of the second gear via a rotating support; wherein the input shaft of the first transmission tooth is connected to the first regulating motor via a clutch transmission, and the input shaft of the second transmission tooth is connected to the second regulating motor via a clutch transmission; The transmission structure includes a third thread arranged on the first rotating part and a fourth thread arranged on the rotating sleeve, the third thread cooperates with the first driving block thread, the fourth thread cooperates with the second driving block thread, and the pitch parameters of the third thread and the fourth thread are the same.

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