Pole piece and sodium ion battery

Abstract

The utility model provides a pole piece and a sodium ion battery, and the pole piece comprises an insulating layer, the positive electrode metal layer is arranged on one side of the insulating layer, and one side, far away from the insulating layer, of the positive electrode metal layer is provided with a positive electrode coating area and a positive electrode leading-out area; the negative electrode metal layer is arranged on the other side of the insulating layer, a negative electrode coating area and a negative electrode leading-out area are arranged on the side, away from the insulating layer, of the negative electrode metal layer, and the positive electrode coating is coated on the positive electrode coating area; the negative electrode coating is coated on the negative electrode coating area; and in the width direction of the pole piece, the positive electrode lead-out region and the negative electrode lead-out region are separated from each other. According to the pole piece disclosed by the utility model, the positive pole lug and the negative pole lug can be formed in the opposite directions of the pole piece, so that the positive pole and the negative pole are integrated on the single pole piece, the positive pole lug and the negative pole lug are conveniently subjected to die cutting, the size and the consistency of die cutting are favorably controlled, and meanwhile, the coating time and the foil consumption are also favorably reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and more specifically, to a pole piece and a sodium ion battery. Background Art

[0002] In the related technology, large cylindrical batteries mainly use the cutting and stacking process through a laser die-cutting and winding machine to die-cut, wind, and pat the copper foil or aluminum foil exposed by the pole piece, and then weld the collector plate to assemble the battery. In the existing scheme, the positive electrode dressing and the negative electrode dressing are coated on two foils respectively. Two pole pieces and two diaphragms need to be used at the same time during winding. The production efficiency is low and the energy density is low. In addition, since the positive and negative pole ears need to be die-cut at the same time during die-cutting, and the positive and negative pole ears are distributed on two pole pieces, it is difficult to control the size during die-cutting and the consistency is poor. Utility Model Content

[0003] The utility model provides a new technical solution for pole pieces, which can at least solve one of the problems of low pole piece production efficiency, low energy density and great die-cutting difficulty in the prior art.

[0004] The utility model also provides a sodium ion battery, comprising the above-mentioned pole piece.

[0005] According to the first aspect of the utility model, a pole piece is provided, comprising: an insulating layer; a positive electrode metal layer, the positive electrode metal layer is arranged on one side of the insulating layer, and the positive electrode metal layer has a positive electrode coating area and a positive electrode lead-out area on the side away from the insulating layer; a negative electrode metal layer, the negative electrode metal layer is arranged on the other side of the insulating layer, and the negative electrode metal layer has a negative electrode coating area and a negative electrode lead-out area on the side away from the insulating layer, a positive electrode coating, the positive electrode coating is coated on the positive electrode coating area; a negative electrode coating, the negative electrode coating is coated on the negative electrode coating area; wherein, in the width direction of the pole piece, the positive electrode lead-out area is spaced apart from the negative electrode lead-out area.

[0006] Optionally, in the thickness direction of the pole piece, the positive electrode lead-out region is spaced apart from the negative electrode lead-out region.

[0007] Optionally, in the width direction of the pole piece, the positive lead-out region is located at one end of the pole piece, the negative lead-out region is located at the other end of the pole piece, and the positive electrode coating and the negative electrode coating are located between the positive lead-out region and the negative electrode lead-out region.

[0008] Optionally, a projection of the positive electrode coating along the thickness direction of the pole piece coincides with a projection of the negative electrode coating along the thickness direction of the pole piece.

[0009] Optionally, in the width direction of the pole piece, the width of the insulating layer is L1, the width of the positive electrode metal layer is L2, the width of the negative electrode metal layer is L3, and L1>L2 and L1>L3.

[0010] Optionally, the insulating layer is a PET film.

[0011] Optionally, the positive electrode metal layer and the negative electrode metal layer are both aluminum foil.

[0012] Optionally, a portion of the positive electrode metal layer provided with the positive electrode lead-out region is formed as a positive electrode lug, and a portion of the negative electrode metal layer provided with the negative electrode lead-out region is formed as a negative electrode lug.

[0013] Optionally, in the length direction of the pole piece, the positive pole tab and the negative pole tab are cut off at a preset distance.

[0014] According to a second aspect of the utility model, a sodium ion battery is provided, comprising: a pole piece, the pole piece being any one of the pole pieces described in the above embodiments, and a diaphragm, the diaphragm being stacked on one side of the pole piece; wherein the pole piece and the diaphragm are wound to form a multilayer structure.

[0015] Optionally, the portion of the positive electrode metal layer provided with the positive electrode lead-out area is formed as a positive electrode ear, and the portion of the negative electrode metal layer provided with the negative electrode lead-out area is formed as a negative electrode ear, and in the length direction of the electrode sheet, the positive electrode ear and the negative electrode ear are cut off at a preset distance, and the positive electrode ear and the negative electrode ear are respectively bent toward the insulating layer.

[0016] According to the pole piece of the utility model, a positive electrode metal layer, an insulating layer and a negative electrode metal layer are superimposed to form a composite foil. By coating the positive electrode coating and the negative electrode coating on both sides of a single foil respectively, and staggering the positive electrode lead-out area of ​​the positive electrode metal layer and the negative electrode lead-out area of ​​the negative electrode metal layer in the width direction of the pole piece, the pole piece can form a positive pole ear and a negative pole ear in the opposite direction of itself, thereby integrating the positive electrode and the negative electrode on a single pole piece, facilitating die-cutting of the positive pole ear and the negative pole ear, and facilitating the control of the die-cutting size and consistency, and also facilitating the reduction of coating time and foil consumption. In addition, only one pole piece and one diaphragm are needed in the winding core wound by the pole piece of this embodiment, which is conducive to improving the winding efficiency, reducing the weight of the winding core, and increasing the energy density of the winding core.

[0017] Other features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.

[0019] Figure 1 It is a cross-sectional view of a composite foil in a pole piece according to an embodiment of the utility model;

[0020] Figure 2 is a cross-sectional view of a pole piece according to an embodiment of the utility model;

[0021] Figure 3 It is a cross-sectional view of a stacked pole piece and a diaphragm according to an embodiment of the utility model;

[0022] Figure 4 is a schematic diagram of a roll core in a sodium ion battery according to an embodiment of the utility model;

[0023] Figure 5 It is a schematic diagram of a sodium ion battery production device according to an embodiment of the utility model.

[0024] Reference numerals

[0025] Pole piece 1; Diaphragm 2; Process diaphragm 3;

[0026] Composite foil 10; positive electrode metal layer 11; positive electrode coating area 111; positive electrode lead-out area 112; positive electrode ear 113; insulating layer 12; negative electrode metal layer 13; negative electrode coating area 131; negative electrode lead-out area 132; negative electrode ear 133;

[0027] Positive electrode coating 20;

[0028] Negative electrode coating 30;

[0029] Winding core 300; sodium ion battery production equipment 200; first unwinding roller 201; first winding roller 202; second winding roller 203. DETAILED DESCRIPTION

[0030] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0031] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present invention, its application, or uses.

[0032] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0033] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0034] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0035] The following first describes in detail the pole piece 1 according to an embodiment of the utility model with reference to the accompanying drawings.

[0036] like Figures 1 to 5 As shown, the pole piece 1 according to the embodiment of the utility model comprises: an insulating layer 12 , a positive electrode metal layer 11 , a negative electrode metal layer 13 , a positive electrode coating 20 and a negative electrode coating 30 .

[0037] Specifically, the positive electrode metal layer 11 is provided on one side of the insulating layer 12, and the positive electrode metal layer 11 has a positive electrode coating area 111 and a positive electrode lead-out area 112 on the side away from the insulating layer 12. The negative electrode metal layer 13 is provided on the other side of the insulating layer 12, and the negative electrode metal layer 13 has a negative electrode coating area 131 and a negative electrode lead-out area 132 on the side away from the insulating layer 12. The positive electrode coating 20 is applied to the positive electrode coating area 111. The negative electrode coating 30 is applied to the negative electrode coating area 131. In the width direction of the pole piece 1, the positive electrode lead-out area 112 is spaced apart from the negative electrode lead-out area 132.

[0038] In other words, the electrode sheet 1 according to the embodiment of the utility model is mainly composed of an insulating layer 12, a positive electrode metal layer 11, a negative electrode metal layer 13, a positive electrode coating 20 and a negative electrode coating 30. Among them, the insulating layer 12, the positive electrode metal layer 11 and the negative electrode metal layer 13 are stacked to form a composite foil 10, in which the insulating layer 12 can be used as a supporting structure for carrying the positive electrode metal layer 11 and the negative electrode metal layer 13.

[0039] For ease of explanation, the two sides of the insulating layer 12 can be defined as the front side and the back side, respectively. The positive metal layer 11 can be arranged on the front side of the insulating layer 12 , and the negative metal layer 13 can be arranged on the back side of the insulating layer 12 .

[0040] In addition, the insulating layer 12 can have an insulating effect to prevent the positive metal layer 11 and the negative metal layer 13 from contacting and causing a short circuit. The positive metal layer 11 and the negative metal layer 13 can have good electrical conductivity.

[0041] The positive metal layer 11 and the negative metal layer 13 have a first side and a second side, respectively. The first side of the positive metal layer 11 is opposite to the back side of the insulating layer 12, and the second side of the positive metal layer 11 can be divided into a positive electrode coating area 111 and a positive electrode lead-out area 112. The first side of the negative metal layer 13 is opposite to the back side of the insulating layer 12, and the second side of the negative metal layer 13 can be divided into a negative electrode coating area 131 and a negative electrode lead-out area 132.

[0042] The positive electrode coating 20 and the negative electrode coating 30 can be dressings coated on both sides of the composite foil 10, respectively. The positive electrode coating area 111 can be coated with the positive electrode coating 20, and the negative electrode coating area 131 can be coated with the negative electrode coating 30, that is, the positive electrode coating 20 and the negative electrode coating 30 can be coated on both sides of the single composite foil 10, respectively, so as to integrate the positive and negative polarities in the single electrode sheet 1. Therefore, in the production process of the electrode sheet 1, only a single composite foil 10 needs to be coated, which is conducive to reducing the time of the coating process and saving foil. At the same time, in the winding process, only one electrode sheet 1 and one separator 2 need to be wound, which is conducive to speeding up the winding efficiency, reducing the weight of the core 300, and increasing the energy density of the core 300.

[0043] It should be noted that the thickness direction of the electrode 1, the width direction of the electrode 1 and the length direction of the electrode 1 are the corresponding directions when the electrode 1 is laid flat. Figure 2 and Figure 3 In the up-down direction, the width direction of the pole piece 1 can be Figure 2 and Figure 3 In the left and right directions, the length direction of the pole piece 1 can be Figure 2 and Figure 3 The thickness direction of the pole piece 1, the width direction of the pole piece 1 and the length direction of the pole piece 1 are perpendicular to each other.

[0044] In the winding process, the pole piece 1 is wound along its own length direction, and both ends of the pole piece 1 in the width direction can be formed as the two ends of the winding core 300 .

[0045] Neither the positive lead-out region 112 nor the negative lead-out region 132 is coated with dressing, so a step structure can be formed between the positive lead-out region 112 and the positive electrode coating 20 on the adjacent positive electrode coating region 111 , and a step structure can also be formed between the negative lead-out region 132 and the negative electrode coating 30 on the adjacent negative electrode coating region 131 .

[0046] In the width direction of the pole piece 1, the positive lead-out area 112 and the negative lead-out area 132 can be spaced apart. Since the positive metal layer 11 and the negative metal layer 13 have good conductivity, the positive lead-out area 112 can lead out the positive electrode of the pole piece 1, and the negative lead-out area 132 can lead out the negative electrode of the pole piece 1. In other words, a single composite foil 10 can reserve blank metal layers in opposite directions as the positive electrode ear 113 and the negative electrode ear 133, respectively, to integrate the positive and negative polarities in the single pole piece 1.

[0047] Therefore, according to the pole piece 1 of the embodiment of the utility model, the positive electrode metal layer 11, the insulating layer 12 and the negative electrode metal layer 13 are superimposed to form a composite foil 10. By coating the positive electrode coating 20 and the negative electrode coating 30 on both sides of the single foil, and staggering the positive electrode lead-out area 112 of the positive electrode metal layer 11 and the negative electrode lead-out area 132 of the negative electrode metal layer 13 in the width direction of the pole piece 1, the pole piece 1 can form a positive electrode ear 113 and a negative electrode ear 133 in the opposite direction of itself, so that the positive electrode and the negative electrode are integrated on the single pole piece 1, and the positive electrode ear 113 and the negative electrode ear 133 are conveniently die-cut, which is conducive to controlling the size and consistency of the die-cutting, and is also conducive to reducing the coating time and foil consumption. In addition, only one pole piece 1 and one separator 2 are needed in the winding core 300 wound by the pole piece 1 of this embodiment, which is conducive to improving the winding efficiency, reducing the weight of the winding core 300, and improving the energy density of the winding core 300.

[0048] In a specific embodiment of the present invention, in the thickness direction of the electrode sheet 1 , the positive electrode lead-out region 112 is spaced apart from the negative electrode lead-out region 132 .

[0049] Specifically, the insulating layer 12, the positive electrode metal layer 11 and the negative electrode metal layer 13 can be thin layer structures with uniform thickness. Since the positive electrode metal layer 11 is arranged on one side of the insulating layer 12 and the negative electrode metal layer 13 is arranged on the other side of the insulating layer 12, the positive electrode metal layer 11 and the negative electrode metal layer 13 are spaced apart in the thickness direction of the electrode sheet 1, and the positive electrode lead-out region 112 and the negative electrode lead-out region 132 are spaced apart.

[0050] In this embodiment, the positive lead-out area 112 and the negative lead-out area 132 are staggered in the thickness direction of the electrode sheet 1, which is beneficial to integrating the positive and negative electrodes on the single electrode sheet 1, facilitating the die-cutting of the positive ear 113 and the negative ear 133, and is beneficial to controlling the size and consistency of the die-cutting, and is also beneficial to reducing the coating time and foil consumption.

[0051] In addition, the portion of the positive electrode metal layer 11 corresponding to the positive electrode lead-out region 112 can be formed as a positive electrode ear 113, and the portion of the negative electrode metal layer 13 corresponding to the negative electrode lead-out region 132 can be formed as a negative electrode ear 133. The positive electrode ear 113 and the negative electrode ear 133 can be spaced apart in the thickness direction of the electrode sheet 1 to form a gap, and the distance of the gap is equal to the distance of the insulating layer 12.

[0052] According to one embodiment of the utility model, in the width direction of the pole piece 1, the positive lead-out area 112 is located at one end of the pole piece 1, the negative lead-out area 132 is located at the other end of the pole piece 1, and the positive electrode coating 20 and the negative electrode coating 30 are located between the positive lead-out area 112 and the negative lead-out area 132.

[0053] Specifically, if Figures 1 to 3 As shown, the positive lead-out region 112 can be located at the right end of the electrode sheet 1 , and the negative lead-out region 132 can be located at the left end of the electrode sheet 1 , so that the positive lead-out region 112 and the negative lead-out region 132 are located in opposite directions of the electrode sheet 1 .

[0054] In addition, the positive electrode lead-out region 112 and the negative electrode lead-out region 132 may face opposite directions.

[0055] The positive electrode coating region 111 and the negative electrode coating region 131 may be located between left and right ends of the pole piece 1 , so that the positive electrode coating 20 and the negative electrode coating 30 are located between left and right ends of the pole piece 1 .

[0056] In this embodiment, the positive lead-out area 112 and the negative lead-out area 132 are arranged at the two ends of the electrode sheet 1 in its width direction, so that the positive and negative electrodes of the electrode sheet 1 can be led out from the two ends in the width direction of the electrode sheet 1, and then after the electrode sheet 1 is wound into a winding core 300, the positive and negative electrodes can be led out from the two ends of the winding core 300.

[0057] According to some other embodiments of the present invention, the projection of the positive electrode coating 20 along the thickness direction of the pole piece 1 coincides with the projection of the negative electrode coating 30 along the thickness direction of the pole piece 1 .

[0058] That is, the positive electrode coating 20 and the negative electrode coating 30 may be disposed opposite to each other in the thickness direction of the electrode sheet 1 .

[0059] For ease of explanation, a projection plane perpendicular to the thickness direction of the electrode sheet 1 can be defined, and the positive projection of the positive electrode coating 20 on the projection plane can fall within the positive projection of the negative electrode coating 30 on the projection plane. Therefore, the positions of the positive electrode coating 20 and the negative electrode coating 30 in the width direction of the electrode sheet 1 can roughly overlap.

[0060] In the width direction of the electrode sheet 1 , the width of the negative electrode coating 30 is greater than the width of the positive electrode coating 20 , so the orthographic projection of the negative electrode coating 30 can completely cover the orthographic projection of the positive electrode coating 20 .

[0061] In addition, since the positive lead-out area 112 and the negative lead-out area 132 are staggered in the width direction of the electrode sheet 1, the positive lead-out area 112 is located at one end of the positive electrode coating 20, and the negative lead-out area 132 is located at the other end of the positive electrode coating 20, so that the positive electrode and the negative electrode are respectively led out at both ends of the width direction of the electrode sheet 1.

[0062] In some specific embodiments of the present invention, Figure 1 As shown, in the width direction of the electrode piece 1 , the width of the insulating layer 12 is L1 , the width of the positive electrode metal layer 11 is L2 , and the width of the negative electrode metal layer 13 is L3 , L1 > L2 and L1 > L3 .

[0063] Since the positive electrode coating area 111 and the negative electrode coating area 131 are spaced apart in the width direction of the electrode sheet 1, the positive electrode metal layer 11 and the negative electrode metal layer 13 can be partially staggered in the width direction of the electrode sheet 1, and the total length of the positive electrode metal layer 11 and the negative electrode metal layer 13 in the width direction of the electrode sheet 1 is greater than L2 and greater than L3.

[0064] Since the insulating layer 12 plays the role of supporting the metal layer, by setting L1>L2 and L1>L3, the single insulating layer 12 can be used to support the positive electrode metal layer 11 and the negative electrode metal layer 13, which is beneficial to saving foil materials.

[0065] According to some optional embodiments of the present invention, the insulating layer 12 covers the positive electrode metal layer 11 and the negative electrode metal layer 13 respectively.

[0066] Specifically, the orthographic projection of the insulating layer 12 on the above projection plane can cover the orthographic projection of the positive metal layer 11 on the projection plane, and the orthographic projection of the insulating layer 12 on the above projection plane can cover the orthographic projection of the negative metal layer 13 on the projection plane.

[0067] like Figures 1 to 3 As shown, the lower surface of the left end of the insulating layer 12 is covered with a negative metal layer 13, the upper surface of the left end of the insulating layer 12 is not covered with a metal layer, the upper surface of the right end of the insulating layer 12 is covered with a positive metal layer 11, and the lower surface of the right end of the insulating layer 12 is not covered with a metal layer.

[0068] Thus, both the positive electrode metal layer 11 and the negative electrode metal layer 13 are completely supported on the insulating layer 12 .

[0069] According to one embodiment of the present invention, the insulating layer 12 is a PET film. According to some other embodiments of the present invention, the plastic film is a PET film. The PET film has the advantages of high stability, wear resistance, and low cost, and has good insulation performance, and can be used as a good supporting layer for carrying the positive metal layer 11 and the negative metal layer 13.

[0070] In some specific embodiments of the present invention, the positive metal layer 11 and the negative metal layer 13 are both aluminum foils. That is, the composite foil 10 can be a composite aluminum foil, which has the advantages of high safety and light weight. Using composite aluminum foil to prepare the pole piece 1 is conducive to reducing the weight of the battery and improving the energy density of the battery.

[0071] According to some optional embodiments of the present invention, the portion of the positive metal layer 11 provided with the positive lead-out region 112 is formed as a positive electrode lug 113 , and the portion of the negative metal layer 13 provided with the negative lead-out region 132 is formed as a negative electrode lug 133 .

[0072] Specifically, Figures 1 to 3 As shown, the uncoated portion of the right end of the positive metal layer 11 can be used as a positive electrode ear 113 to lead out the positive electrode of the pole piece 1, and the uncoated portion of the left end of the negative metal layer 13 can be used as a negative electrode ear 133 to lead out the negative electrode of the pole piece 1. Therefore, the positive electrode ear 113 is located at the right end of the pole piece 1, and the negative electrode ear 133 is located at the left end of the pole piece 1, which is convenient for winding the pole piece 1.

[0073] In some specific embodiments of the present invention, in the length direction of the electrode sheet 1 , the positive electrode tab 113 and the negative electrode tab 133 are cut off at a preset distance.

[0074] Specifically, on the original composite foil 10, the metal layer used to form the positive electrode ear 113 or the negative electrode ear 133 may be continuous in the length direction of the composite foil 10. After coating the composite foil 10 on both sides, the positive electrode metal layer 11 and the negative electrode metal layer 13 may be die-cut so that the continuous metal layer is cut off by 1 mm at each preset distance to form a plurality of discontinuous positive electrode ears 113 and negative electrode ears 133. Adjacent positive electrode ears 113 or adjacent negative electrode ears 133 may be spaced 1 mm apart to facilitate the bending process of the electrode ears during the battery preparation process.

[0075] Optionally, the die-cutting of the pole ear may be beveled, and the pole ear after die-cutting may be arranged obliquely relative to the width direction of the pole piece 1 .

[0076] The present utility model also provides a sodium ion battery, which includes: a pole piece 1 and a diaphragm 2. Specifically, the pole piece 1 is the pole piece 1 according to any of the above embodiments, and the diaphragm 2 is stacked on one side of the pole piece 1. The pole piece 1 and the diaphragm 2 are wound to form a winding core 300.

[0077] like Figure 3 As shown, the separator 2 may be disposed on a side of the negative electrode coating 30 away from the composite foil 10 .

[0078] Since the pole piece 1 according to the embodiment of the utility model has the above-mentioned technical effects, the sodium ion battery according to the embodiment of the utility model also has the corresponding technical effects, that is, the pole piece 1 can form a positive pole ear 113 and a negative pole ear 133 in the opposite direction of itself, so as to integrate the positive and negative electrodes on the single pole piece 1, and facilitate die-cutting of the positive pole ear 113 and the negative pole ear 133, which is conducive to controlling the size and consistency of the die-cutting, and is also conducive to reducing the coating time and foil consumption. And the winding core 300 requires a pole piece 1 and a diaphragm 2 for winding, which is conducive to improving the winding efficiency, reducing the weight of the winding core 300, and improving the energy density of the winding core 300.

[0079] According to some other embodiments of the utility model, the portion of the positive metal layer 11 having the positive lead-out area 112 is formed as a positive electrode ear 113, and the portion of the negative metal layer 13 having the negative electrode lead-out area 132 is formed as a negative electrode ear 133. In the length direction of the electrode sheet 1, the positive electrode ear 113 and the negative electrode ear 133 are cut off at every preset distance, and the positive electrode ear 113 and the negative electrode ear 133 are respectively bent toward the insulating layer 12.

[0080] Specifically, Figures 1 to 3 As shown, the positive electrode ear 113 can be bent downward, and the negative electrode ear 133 can be bent upward. In the winding core 300, since the positive electrode metal layer 11 and the negative electrode metal layer 13 are separated by the insulating layer 12, the positive electrode ear 113 and the negative electrode ear 133 are respectively bent toward the insulating layer 12, so that the positive electrode ear 113 and the negative electrode ear 133 can be exposed outward at both ends of the winding core 300 to facilitate welding of the current collecting plate.

[0081] In some specific embodiments of the present invention, the positive electrode tab 113 is bent from outside to inside, and the negative electrode tab 133 is bent from inside to outside.

[0082] The inner and outer directions of the winding core 300 can be defined as the inner and outer directions of the positive electrode tab 113 and the negative electrode tab 133. Figure 3 As shown, in the flattened state, the negative electrode coating 30 in the electrode sheet 1 is close to the separator 2, and the positive electrode coating 20 in the electrode sheet 1 is far away from the separator 2. Figure 4 As shown, the innermost circle of the winding core 300 is the diaphragm 2. Therefore, in the same circle of the electrode sheet 1, the positive electrode metal layer 11 is located outside the insulating layer 12, and the negative electrode metal layer 13 is located inside the insulating layer 12. Since the positive electrode ear 113 and the negative electrode ear 133 are bent toward the insulating layer 12 respectively, the positive electrode ear 113 needs to be bent from the outside to the inside, and the negative electrode ear 133 needs to be bent from the inside to the outside, so that the positive electrode ear 113 and the negative electrode ear 133 are exposed outward at both ends of the winding core 300 to facilitate welding of the current collecting plate.

[0083] The preparation process of the sodium ion battery of this embodiment is described in detail below.

[0084] S1, using composite aluminum foil for positive electrode coating, that is, coating a positive electrode metal layer 11 on one side of the composite foil 10. The positive electrode aluminum foil and the negative electrode aluminum foil need to reserve empty foil in different directions without coating material, which are used as positive electrode ears 113 and negative electrode ears 133 for subsequent winding and flattening and welding with the current collecting plate.

[0085] S2, using the sheet material that has been coated with positive electrode, and coating the other side with negative electrode, that is, coating the negative electrode metal layer 13 on the other side of the composite foil material 10. During the coating and winding, a high-strength non-conductive process diaphragm 3 is used to wind together to isolate the positive and negative electrodes, ensuring that the process diaphragm 3 does not break or stick to the material during the coating and winding process, and the positive and negative electrodes are not short-circuited.

[0086] S3, the sheet coated with positive and negative electrodes is rolled up and rolled and cut. It is ensured that the separator 3 does not break or stick to the material during the rolling and cutting process, and the positive and negative electrodes do not short-circuit.

[0087] S4, winding the cut sheets. Before the electrode 1 and the diaphragm 2 are wound, the electrode 1 and the process diaphragm 3 need to be separated, and then a piece of electrode 1 and a piece of diaphragm 2 are wound to form a winding core 300.

[0088] S5, bend and flatten the positive electrode tab 113 from the outer edge of the winding core 300 to the inside of the winding core 300, bend and flatten the negative electrode tab 133 from the inside of the winding core 300 to the outer edge, and then weld the positive electrode tab 113 and the negative electrode tab 133 to the collector plates for assembly.

[0089] like Figure 5 As shown, the sodium ion battery production equipment 200 may include a first unwinding roller 201, a second unwinding roller (not shown in the figure), a first winding roller 202 and a second winding roller 203. The first unwinding roller 201 can be used to release the electrode 1, the second unwinding roller can be used to release the diaphragm 2, the first winding roller 202 can wind up the diaphragm 3, and the second winding roller 203 can be used to wind up the electrode 1 and the diaphragm 2.

[0090] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A pole piece, characterized in that: include: Insulation layer; A positive electrode metal layer, the positive electrode metal layer is arranged on one side of the insulating layer, and the positive electrode metal layer has a positive electrode coating area and a positive electrode lead-out area on a side away from the insulating layer; A negative electrode metal layer, the negative electrode metal layer is arranged on the other side of the insulating layer, and the negative electrode metal layer has a negative electrode coating area and a negative electrode lead-out area on a side away from the insulating layer, A positive electrode coating, the positive electrode coating is coated on the positive electrode coating area; A negative electrode coating, the negative electrode coating is coated on the negative electrode coating area; Wherein, in the width direction of the electrode sheet, the positive electrode lead-out region is spaced apart from the negative electrode lead-out region.

2. The pole piece according to claim 1, characterized in that: The positive electrode lead-out region is spaced apart from the negative electrode lead-out region in a thickness direction of the electrode sheet.

3. The pole piece according to claim 1, characterized in that: In the width direction of the pole piece, the positive lead-out region is located at one end of the pole piece, the negative lead-out region is located at the other end of the pole piece, and the positive electrode coating and the negative electrode coating are located between the positive electrode lead-out region and the negative electrode lead-out region.

4. The pole piece according to claim 1, characterized in that: The projection of the positive electrode coating along the thickness direction of the pole piece coincides with the projection of the negative electrode coating along the thickness direction of the pole piece.

5. The pole piece according to claim 1, characterized in that: In the width direction of the electrode sheet, the width of the insulating layer is L1, the width of the positive electrode metal layer is L2, and the width of the negative electrode metal layer is L3, L1>L2 and L1>L3.

6. The pole piece according to claim 5, characterized in that: The insulating layer covers the positive electrode metal layer and the negative electrode metal layer respectively.

7. The pole piece according to claim 1, characterized in that: The insulating layer is a PET film.

8. The pole piece according to claim 1, characterized in that: The positive electrode metal layer and the negative electrode metal layer are both aluminum foils.

9. The pole piece according to any one of claims 1 to 8, characterized in that: The portion of the positive electrode metal layer where the positive electrode lead-out region is provided is formed as a positive electrode tab, and the portion of the negative electrode metal layer where the negative electrode lead-out region is provided is formed as a negative electrode tab.

10. The pole piece according to claim 9, characterized in that: In the length direction of the electrode sheet, the positive electrode tab and the negative electrode tab are cut off at a preset distance.

11. A sodium ion battery, characterized in that: include: A pole piece, wherein the pole piece is the pole piece according to any one of claims 1 to 10; A diaphragm, the diaphragm is stacked on one side of the pole piece; Wherein, the pole piece and the diaphragm are wound to form a winding core.

12. The sodium ion battery according to claim 11, characterized in that: The portion of the positive electrode metal layer provided with the positive electrode lead-out area is formed as a positive electrode ear, and the portion of the negative electrode metal layer provided with the negative electrode lead-out area is formed as a negative electrode ear. In the length direction of the electrode sheet, the positive electrode ear and the negative electrode ear are cut off at a preset distance, and the positive electrode ear and the negative electrode ear are respectively bent toward the insulating layer.

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