Pole piece, single battery and pole piece manufacturing method

Abstract

The application relates to the technical field of lithium batteries, and discloses a pole piece, a single battery and a pole piece manufacturing method. The pole piece comprises a plurality of foils, a plurality of first coating layers and a plurality of second coating layers. The plurality of foils are arranged at intervals, one side or both sides of the foils are provided with the first coating layers, and the second coating layers are arranged between adjacent foils to form a pole piece with a non-continuous foil structure. The second coating layers can provide a partial lithium deintercalation space between adjacent foils, and can effectively reduce the expansion degree of the pole piece in the first direction. Therefore, when the pole piece is used to manufacture an electric core, partial expansion reserved space can be released, the battery energy density can be improved, and in addition, the expansion force transmitted to the outside by the electric core can be effectively weakened, so that the safety is improved. The single battery with the pole piece also has the above advantages.

Description

Technical Field

[0001] This application relates to the field of lithium battery technology, and in particular to an electrode, a single cell, and a method for manufacturing the electrode. Background Technology

[0002] Conventional electrodes consist of a single layer of foil (copper or aluminum foil) as the current collector, coated with active material on one or both sides for lithium-ion insertion or extraction to supply energy. However, battery cells based on this type of electrode exhibit significant expansion during charging and discharging. The expansion force transmitted by the cell negatively impacts the safety and lifespan of the battery module or pack assembled from it. To overcome this problem, related technologies provide additional volumetric space inside the battery to reduce bulk margin and reserve extra space for cell expansion, thereby reducing the risks associated with expansion. However, this also results in insufficient filling of the internal space by the cell, limiting the improvement of battery energy density. Summary of the Invention

[0003] This application aims to at least solve one of the technical problems existing in the prior art. To this end, this application proposes an electrode that can reduce cell expansion and release some of the expansion reserve space.

[0004] This application also proposes a method for manufacturing an electrode sheet.

[0005] This application also proposes a single-cell battery having the electrode.

[0006] An electrode sheet according to a first aspect of this application includes a plurality of foils, a plurality of first coatings, and a plurality of second coatings, wherein the plurality of foils are spaced apart along a first direction, the first coating includes a first active material, the first coating is disposed along a second direction on one or both sides of the foil to form a plurality of electrode segments, the second direction being perpendicular to the first direction; the second coating includes a second active material, the second coating is disposed between adjacent electrode segments, and the second coating is connected to the foil and / or the first coating.

[0007] The electrode sheet of the first aspect of this application has at least the following beneficial effects: multiple foils are spaced apart, a first coating is provided on one or both sides of the foil to form multiple electrode segments, and a second coating is provided between adjacent electrode segments to form an electrode sheet with a discontinuous foil structure. The second coating can provide partial lithium insertion / extraction space between adjacent electrode segments, thereby effectively reducing the overall expansion degree of the electrode sheet in the first direction. Therefore, when the electrode sheet is used to manufacture a battery cell, it can release some of the expansion reserved space, which is beneficial to improving the battery energy density. In addition, it can also effectively weaken the expansion force transmitted by the battery cell to the outside, thereby improving safety.

[0008] According to some embodiments of this application, the electrode sheet, along the first direction, has the first coating aligned with the foil.

[0009] According to some embodiments of this application, the foil has two opposing ends along the first direction; in a plurality of foils, at least one end of a portion of the foil has a gap with the second coating.

[0010] According to some embodiments of this application, the size of the foil having a gap between it and the second coating along the first direction is smaller than the size of the first coating.

[0011] According to some embodiments of this application, the electrode end includes a first end face and a second end face connected together, the first end face abutting against the second coating, the second end face being inclined in a direction away from the second coating, and a gap being formed between the second end face and the second coating.

[0012] According to some embodiments of this application, in the electrode sheet, along the second direction, the second coating is also connected to the first coating, and the thickness of the second coating is equal to the sum of the thicknesses of the foil and the first coating.

[0013] According to some embodiments of this application, in the electrode sheet along the first direction, a portion of the foil material of the electrode sheet is smaller than the size of the remaining foil material, and / or, a portion of the second coating of the electrode sheet is larger than the size of the remaining second coating.

[0014] A single-cell battery according to a second aspect embodiment of this application includes a casing and a cell, wherein the cell is placed inside the casing, and the cell includes a separator and an electrode sheet as described in the first aspect embodiment above, wherein a plurality of the electrode sheets are stacked on top of each other, and the separator is provided on both sides of each electrode sheet.

[0015] The single-cell battery of the second aspect of this application has at least the following beneficial effects: the separators on both sides of the electrode can effectively insulate, and the cell is made of the electrode of the above embodiment, which can effectively reduce expansion, thereby releasing part of the expansion space reserved inside the casing, which is beneficial to improving the energy density of the battery. In addition, it can also effectively weaken the expansion force transmitted by the cell to the outside, thereby improving safety.

[0016] According to some embodiments of the present application, the single-cell battery is formed by winding the electrode and the separator along a set direction. The battery cell is divided into a stacking region and a bending region. In the electrode, the width of the foil corresponding to the bending region is L1, and the width of the second coating corresponding to the bending region is W1; the width of the foil corresponding to the stacking region is L2, and the width of the second coating corresponding to the stacking region is W2; wherein, L1 < L2, and / or, W1 > W2.

[0017] The electrode manufacturing method according to the third aspect of this application includes: Prepare foil, a first slurry containing a first active material, and a second slurry containing a second active material; Multiple foils are spaced apart along a first direction; The first slurry is applied to the side of the foil in the thickness direction, and the second slurry is applied to fill the spaces between adjacent foils, and the first and second slurries are cured. The cured first slurry and second slurry are rolled in the thickness direction of the foil to form a first coating on the side of the foil in the thickness direction of the first slurry, and to form a second coating between adjacent foils.

[0018] The electrode manufacturing method of the third aspect of this application has at least the following advantages: the method enables multiple foils to be spaced apart and form a first coating on one or both surfaces in the thickness direction of the foils, and enables a second coating to be formed between adjacent foils, thereby producing an electrode with a discontinuous foil structure.

[0019] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0020] Figure 1 This is a cross-sectional schematic diagram of an embodiment of the electrode sheet of this application; Figure 2 This is a cross-sectional schematic diagram of an electrode sheet according to another embodiment of this application; Figure 3 This is a schematic diagram of the structure of an electrode sheet according to an embodiment of this application; Figure 4 for Figure 3 A magnified view of part A in the diagram; Figure 5 This is a schematic diagram of the structure of an electrode sheet according to another embodiment of this application; Figure 6 for Figure 5 A magnified view of section B in the diagram; Figure 7 This is a schematic diagram of the structure of an electrode sheet according to another embodiment of this application; Figure 8 for Figure 7 A magnified schematic diagram of point C in the diagram; Figure 9 This is a schematic diagram of a cell in a single battery cell according to an embodiment of this application; Figure 10 for Figure 9 A schematic diagram of the unfolded electrode plates in the diagram; Figure 11 This is a schematic diagram of a cell in a single-cell battery according to another embodiment of this application; Figure 12 This is a schematic flowchart of the electrode manufacturing method according to an embodiment of this application; Figure 13 This is a schematic diagram showing some detailed steps in an embodiment of the electrode manufacturing method of this application; Figure 14 This is a schematic diagram showing some detailed steps in an electrode manufacturing method according to another embodiment of this application.

[0021] Figure label: Electrode 100, foil 101, first coating 102, second coating 103, gap 104, end 105, first end face 106, second end face 107, first segment 108, second segment 109; Cell 200, separator 201, stacking area 202, bending area 203; First slurry 300, second slurry 400.

[0022] Separator 500, first filling area 501, second filling area 502. Detailed Implementation

[0023] The following will clearly and completely describe the concept and technical effects of this application in conjunction with embodiments, so as to fully understand the purpose, features and effects of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are all within the scope of protection of this application.

[0024] In the description of the embodiments of this application, if directional descriptions are involved, such as "up", "down", "front", "back", "left", "right" etc., indicating the directional or positional relationship based on the directional or positional relationship shown in the drawings, it is only for the convenience of describing this application and simplifying the description, and is not intended to indicate or imply that the device or device referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0025] In the description of the embodiments of this application, if a feature is referred to as "setting," "fixing," "connecting," or "installing" on another feature, it can be directly set, fixed, or connected to the other feature, or it can be indirectly set, fixed, connected, or installed on the other feature. In the description of the embodiments of this application, if "several" is involved, it means one or more; if "multiple" is involved, it means two or more; if "greater than," "less than," or "exceeds," it should be understood as excluding the stated number; if "above," "below," or "within," it should be understood as including the stated number. If "first" or "second" is involved, it should be understood as used to distinguish technical features, and not as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of the indicated technical features.

[0026] In lithium batteries, cell expansion is a common problem. The expansion force transmitted by the cell directly affects the safety and lifespan of the battery module or battery pack. Currently, the common solution is to reserve extra expansion space for the cell inside the battery. However, this results in insufficient filling of the cell within the internal space, making it difficult to improve the battery's energy density. This application provides an electrode and a single-cell battery. The electrode has a discontinuous foil structure, which effectively reduces the size of the electrode expansion. When a cell made from this electrode is used in a single-cell battery, the cell expansion problem is significantly improved, thereby reducing the expansion force transmitted externally. This application also provides an electrode manufacturing method. The embodiments of this application are described in detail below with reference to the accompanying drawings: Figure 1 This is a cross-sectional schematic diagram of an electrode sheet according to an embodiment of this application. Figure 2 This is a cross-sectional schematic diagram of an electrode sheet according to another embodiment of this application, with reference to... Figure 1 and Figure 2 The electrode 100 of the first aspect of this application includes a plurality of foils 101, a plurality of first coatings 102, and a plurality of second coatings 103. The foils 101 are made of conventional foil materials used in electrode production, such as copper foil or aluminum foil. The first coatings 102 include a first active material, and the second coatings 103 include a second active material. The plurality of foils 101 are spaced apart along a first direction, thus having a predetermined spacing between adjacent foils 101. The first coatings 102 are disposed along a second direction perpendicular to the first direction on one or both surfaces of the foils 101, forming a plurality of electrode segments. Figure 1 The structure shown is that a first coating 102 is provided on one side surface of the foil 101 along the second direction. Figure 2The diagram illustrates a structure in which a first coating 102 is provided on both surfaces of a foil 101 along a second direction. A second coating 103 is disposed between adjacent electrode segments, connecting the foil 101 and / or the first coating 102 to form an electrode 100 with a discontinuous foil 101 structure. In the above embodiment, the first coating 102 can be made using a first slurry containing a first active material, which also includes a conductive agent, a binder, etc. Similarly, the second coating 103 can be made using a second slurry containing a second active material, which also includes a conductive agent, a binder, etc. The first and second slurries can be selected from slurries commonly used in manufacturing electrode coatings. In practice, the specific materials and proportions of the first and second active materials can be the same or different.

[0027] In the electrode 100 of this application embodiment, the dimensions of the foil 101, the first coating 102, and the second coating 103 along the first direction can be defined as width, and the dimensions along the second direction can be defined as thickness. Therefore, multiple foils 101, multiple first coatings 102, and multiple second coatings 103 can form an electrode 100 with a set length and thickness through the above arrangement. Since the second coating 103 can provide partial lithium insertion / extraction space between adjacent electrode segments, the expansion degree of adjacent foils 101 and first coatings 102 along the first direction is reduced. Thus, the overall expansion degree of the electrode 100 in the first direction can be effectively reduced.

[0028] The electrode 100 of this application embodiment can be used to make positive and / or negative electrode sheets, thereby forming a battery cell. Compared with conventional battery cells, the battery cell made with the electrode 100 of this application embodiment has a smaller degree of expansion during charging and discharging, thus reducing the required expansion allowance space when grouping or packing, thereby releasing some of the expansion allowance space and improving the group margin design. This space can be used to increase the size of the battery cell, for example, by increasing the number of electrode 100 layers or the thickness of the active material of a single electrode 100 to form a thicker battery cell, thereby improving the lithium-ion volumetric energy density; or, this space can also be used to reduce the size of the module or battery pack housing, which is beneficial to improving the overall volumetric energy density of the battery pack. Compared with conventional solutions, under the same operating conditions, the reduction in the degree of cell expansion can also weaken the expansion force transmitted by the cell to the outside, thereby reducing the squeezing force of the cell on the module or battery pack housing, thereby improving safety.

[0029] Furthermore, during the charging and discharging of the battery cell, the lithium insertion / extraction process typically induces localized stress, leading to delamination at the coating-foil interface. For electrode sheets with traditional structures, the stress caused by expansion mainly exists at the horizontal interface between the coating and the foil, meaning the foil is subjected to tensile and compressive forces at the horizontal interface. This type of stress easily causes localized buckling (localized longitudinal bending imbalance), resulting in wrinkles on the electrode sheet. The electrode sheet 100 of this application embodiment effectively solves this problem. Specifically, during the lithium insertion / extraction process, the electrode sheet 100 of this application embodiment is simultaneously subjected to forces at both the horizontal interface along the first direction and the vertical interface along the second direction (tensile and compressive forces at the horizontal interface, and shear forces at the vertical interface). This reduces the stress imbalance caused by localized stress, thereby reducing wrinkle formation and ensuring the stability of the battery cell.

[0030] refer to Figure 1 and Figure 2 In some embodiments of the electrode 100, along the first direction, the first coating 102 is aligned with the foil 101, and the second coating 103 can be connected to the adjacent foil 101 or the first coating 102, thereby connecting to form a discontinuous foil 101 structure, or the second coating 103 can simultaneously connect the adjacent foil 101 and the first coating 102, achieving connection while ensuring connection stability, thereby improving the overall stability of the electrode 100.

[0031] refer to Figures 3 to 6 In some embodiments of the electrode 100, the foil 101 has two opposing ends 105 along a first direction. Among the plurality of foils 101 of the electrode 100, at least one end 105 of a portion of the foil 101 has a gap 104 between it and the second coating 103, thereby providing more expansion space for the foil 101. The second coating 103 is connected to the first coating 102, thereby forming a discontinuous foil 101 structure. The gap 104 can be formed in various ways, for example: refer to Figure 3 and Figure 4 In some embodiments of the electrode 100, the width of the foil 101 with a gap 104 between it and the second coating 103 along the first direction is smaller than the width of the first coating 102. Thus, a gap 104 is formed between the second coating 103 and the end 105 of the foil 101 along the first direction, which can accommodate a greater degree of expansion. Or, refer to Figure 5 and Figure 6In some embodiments of the electrode 100, the end 105 of the foil 101 with a gap 104 between it and the second coating 103 includes a first end face 106 and a second end face 107 connected together. The first end face 106 is in contact with the second coating 103, and the second end face 107 is inclined in a direction away from the second coating 103. There is a gap 104 between the second end face 107 and the second coating 103, thereby improving the connection stability of adjacent foils 101 through the contact between the first end face 106 and the second coating 103, while providing a certain expansion space through the gap 104. Alternatively, in some embodiments of the electrode 100, along the first direction, there is a gap 104 between the second coating 103 in the electrode 100 and the ends 105 of two adjacent foils 101. This gap 104 can be constructed using the methods described above. Figure 3 and Figure 4 The embodiments shown can also be implemented as described above. Figure 5 and Figure 6 The illustrated implementation may also employ different implementations for the gaps 104 on both sides, for example, see reference. Figure 7 and Figure 8 Along the first direction, the end 105 of the foil 101 with a gap 104 between it and one side of the second coating 103 includes a connected first end face 106 and a second end face 107. The first end face 106 is in contact with the second coating 103, and the second end face 107 is inclined in a direction away from the second coating 103. There is a gap 104 between the second end face 107 and the second coating 103, thereby improving the connection stability of adjacent foils 101 through the contact between the first end face 106 and the second coating 103, while providing a certain expansion space through the gap 104. Along the first direction, the width of the foil 101 with a gap 104 between it and the other side of the second coating 103 is smaller than the width of the first coating 102. Thus, the end 105 of the foil 101 and the second coating 103 form a gap 104 and do not contact each other, which can accommodate a greater degree of expansion.

[0032] refer to Figure 1 and Figure 2 In some embodiments of the electrode 100, along the second direction, the thickness of the second coating 103 is equal to the sum of the thicknesses of the foil 101 and the first coating 102, thereby, with reference to Figure 1 When the foil 101 has a first coating 102 on one side along the second direction, the second coating 103 is aligned with the first coating 102 and the outer side of the foil 101 in the second direction, for reference. Figure 2 When the foil 101 is provided with a first coating 102 on both sides along the second direction, the second coating 103 is aligned with the outer side of the first coating 102 on both sides of the foil 101 in the second direction, thereby ensuring that the electrode 100 has a flat surface.

[0033] In some embodiments of the electrode 100, along the first direction, the width of a portion of the foil 101 of the electrode 100 is smaller than the width of the remaining foil 101. Under the same conditions, the expansion deformation of the foil 101 with a smaller width is smaller. Furthermore, with a section of electrode 100 of the same length as a reference, the electrode 100 with the foil 101 with a smaller width can have more foils 101 spaced apart, thereby having more second coatings 103, which can accommodate a greater degree of expansion.

[0034] refer to Figure 9 When the electrode 100 is used to wind and manufacture the battery cell 200, it is typically wound multiple times from one end of the electrode 100 along a predetermined direction, thereby stacking to form a flat stacked area 202 in the thickness direction, and bending to form a bent area 203 at the bends of each stacked area 202. Therefore, it can be understood that an electrode 100 has multiple first segments 108 for bending and stacking to form the bent area 203, and multiple second segments 109 for stacking to form a flat stacked area 202 in the thickness direction. Since the expansion of the bent area 203 is usually greater than the expansion of the stacked area 202 when the battery cell 200 is in operation, after the electrode 100 is wound to form the battery cell 200, a foil 101 with a smaller width can be provided on the electrode 100 corresponding to the portion used to form the bent area 203, thereby reducing the expansion of the electrode 100 at that location. After winding, this location is in the bent area 203 of the battery cell 200, thus effectively reducing the expansion of the bent area 203.

[0035] Alternatively, in some embodiments, the width of a portion of the second coating 103 of the electrode 100 is greater than the width of the remaining second coating 103, thereby accommodating a greater degree of expansion of the foil 101 and the first coating 102. Specifically, similar to the embodiments described above, a wider second coating 103 can be provided on the first segment 108 of the electrode 100 used for bending and stacking to form the bending region 203, thereby reducing the degree of expansion of the electrode 100 at the first segment 108, and thus effectively reducing the degree of expansion of the bending region 203.

[0036] Alternatively, in some embodiments, the width of a portion of the foil 101 of the electrode 100 is smaller than the width of the remaining foil 101, and the width of the second coating 103 between these smaller foils 101 is larger than the width of the second coating 103 between the other foils 101. Specifically, similar to the embodiments described above, refer to... Figure 10 A narrower foil 101 can be provided on the first segment 108 of the electrode 100 for bending and stacking to form the bending region 203, and a wider second coating 103 can be provided between the narrower foil 101, thereby further reducing the degree of expansion of the electrode 100 at the first segment 108, and thus further reducing the degree of expansion of the bending region 203.

[0037] In some embodiments of the electrode 100 of this application, reference is made to Figure 9 and Figure 10 Along a first direction, the electrode 100 includes a plurality of first segments 108 and a plurality of second segments 109, with each first segment 108 and second segment 109 spaced apart from each other. Specifically, the width of the foil 101 in the first segment 108 is smaller than the width of the foil 101 in the second segment 109, and / or, the width of the second coating 103 in the first segment 108 is greater than the width of the second coating 103 in the second segment 109. Therefore, when the electrode 100 is wound to form a battery cell 200, the second segments 109 can be stacked to form the stacking region 202 of the battery cell 200, and the first segments 108 can be bent and stacked to form the bending region 203 of the battery cell 200, thereby effectively reducing the expansion degree of the bending region 203.

[0038] Of course, the electrode 100 in the above embodiment is also applicable to the structure of a battery cell made by stacking multiple electrode 100s along the thickness direction. The reduction of the expansion degree of each electrode 100 can also weaken the expansion force applied outward by the battery cell.

[0039] Understandably, in practical implementation, the width of the foil 101 along the first direction can be determined according to the actual battery structure and material system design. For example, for a battery cell design with significant expansion, the width of the foil 101 can be reduced. Similarly, the width of the second coating 103 between adjacent foils 101 along the first direction and the thickness along the second direction can be determined according to the magnitude of material expansion. For example, if the designed material system has significant expansion, the width of the second coating 103 can be appropriately increased.

[0040] Figure 9 This is a schematic diagram of a cell in a single-cell battery according to an embodiment of this application. Figure 10 for Figure 9 A schematic diagram of the unfolding of the electrodes. Figure 11 This is a schematic diagram of a cell in a single-cell battery according to another embodiment of this application, with reference to... Figure 9 and Figure 11The second aspect of this application describes a single-cell battery comprising a casing (not shown) and a cell 200, with the cell 200 housed within the casing. The cell 200 includes a separator 201 and electrode plates 100, with multiple electrode plates 100 stacked on top of each other. Each electrode plate 100 has a separator 201 on both sides for effective insulation. The separator 201 is made of conventional materials, such as PP film, PE film, or a mixture of PP film and coating. The separator 201 on both sides of the electrode plate 100 can be made of the same material or different materials. The electrode plate 100 uses the electrode plate 100 described in the first aspect of this application, thus possessing all the advantages of the electrode plate 100 described above. For example, it can effectively reduce the expansion degree of the electrode plate 100, thereby releasing some of the expansion space reserved inside the casing, which is beneficial to improving the battery energy density. Furthermore, it can effectively reduce the expansion force transmitted by the cell 200, thereby improving safety.

[0041] Specifically, the electrode 100 of the above embodiment is used to make positive and / or negative electrode sheets. The positive and negative electrode sheets and the separator 201 are then used to form a battery cell 200. Compared to a conventional battery cell 200, this battery cell 200 exhibits less expansion of the positive and negative electrode sheets during charging and discharging. This releases some of the expansion space inside the casing, which can be used to increase the size of the battery cell 200, for example, by increasing the number of electrode layers 100 to form a thicker cell 200, thereby increasing the lithium-ion volumetric energy density. Alternatively, the size of the casing can be reduced, reducing the required expansion space during assembly or packing, thus releasing some of the expansion space. This space can also be used to reduce the size of the module or battery pack casing, which is beneficial for improving the overall volumetric energy density of the battery pack. With reduced expansion of individual battery cells, when multiple individual cells are assembled into a module or battery pack, the expansion force transmitted from the individual cells can be effectively reduced, thereby improving safety. In addition, as can be seen from the foregoing, the cell 200 made using the electrode 100 of the above embodiment can also reduce the formation of wrinkles, thereby ensuring the stability of the cell 200.

[0042] refer to Figure 9 and Figure 10In some embodiments of the single-cell battery, the electrode 100 and the separator 201 are wound along a predetermined direction to form a cell 200. The cell 200 is divided into a stacking region 202 and a bending region 203. Referring to the electrode 100 of the first aspect embodiment above, the foil 101 is arranged at intervals along a first direction. For ease of understanding, the dimensions of the foil 101, the first coating 102, and the second coating 103 along the first direction can be defined as widths. In the electrode 100 used to wind the cell 200, the width of the foil 101 corresponding to the bending region 203 is L1, and the width of the second coating 103 corresponding to the bending region 203 is W1; the width of the foil 101 corresponding to the stacking region 202 is L2, and the width of the second coating 103 corresponding to the stacking region 202 is W2.

[0043] As can be seen from the electrode 100 in the first aspect embodiment above, under the same conditions, the expansion deformation of the foil 101 with a smaller width is smaller, and a segment of electrode 100 with a smaller width foil 101 can have more foils 101 spaced apart, thereby having more second coatings 103, which can accommodate a greater degree of expansion. Also, under the same conditions, the width of the second coating 103 with a larger width can accommodate a greater degree of expansion of the foil 101 and the first coating 102. Based on this, in some embodiments, L1 and L2 are configured such that L1 < L2, that is, the width L1 of the foil 101 corresponding to the bending region 203 is smaller than the width L2 of the foil 101 corresponding to the stacking region 202. Therefore, the electrode 100 in the bending region 203 has a smaller amount of expansion deformation. Moreover, in the same length of electrode 100 segment, the bending region 203 can be provided with more foil 101, first coating 102 and second coating 103 than the stacking region 202. Therefore, it can accommodate a greater degree of expansion, thereby reducing the degree of expansion of the bending region 203 and solving the problem that the degree of expansion of the bending region 203 in the conventional cell 200 is significantly greater than that of the stacking region 202.

[0044] Alternatively, in some embodiments of the single-cell battery, W1 and W2 are configured such that W1 > W2, that is, the width W1 of the second coating 103 corresponding to the bending region 203 is greater than the width W2 of the second coating 103 corresponding to the stacking region 202. Therefore, compared to the stacking region 202, the second coating 103 of the bending region 203 can accommodate a greater degree of expansion of the foil 101 and the first coating 102, thereby reducing the degree of expansion of the bending region 203 and solving the problem that the degree of expansion of the bending region 203 is significantly greater than that of the stacking region 202 in conventional cells 200.

[0045] Alternatively, in some embodiments of the single cell, L1, L2, W1, and W2 are configured such that L1 < L2 and W1 > W2, that is, the width L1 of the foil 101 corresponding to the bending region 203 is smaller than the width L2 of the foil 101 corresponding to the stacking region 202, and the width W1 of the second coating 103 corresponding to the bending region 203 is larger than the width W2 of the second coating 103 corresponding to the stacking region 202, which can further reduce the degree of expansion of the bending region 203.

[0046] refer to Figure 11 In some embodiments of the single-cell battery, the cell 200 includes multiple electrode sheets 100 and multiple separators 201. The multiple electrode sheets 100 and multiple separators 201 are stacked in sequence along the thickness direction, and each electrode sheet 100 has a separator 201 on both sides to achieve good insulation. Specifically, multiple positive electrode sheets and multiple negative electrode sheets are made from the electrode sheets 100 of the first aspect embodiment above, wherein the positive electrode sheets and negative electrode sheets are stacked alternately in sequence, and separators 201 separate each electrode sheet 100, forming a stacked cell 200 structure. Since the positive electrode sheets and negative electrode sheets are made from the electrode sheets 100 of the first aspect embodiment above, they have all the advantages of the electrode sheets 100 of the above embodiments, such as effectively reducing the expansion degree of the electrode sheets 100, thereby releasing part of the expansion space reserved inside the casing, which is beneficial to improving the energy density of the battery. In addition, it can also effectively reduce the expansion force transmitted by the cell 200 to the outside, thereby improving safety.

[0047] Figure 12 This is a schematic flowchart of the electrode manufacturing method according to an embodiment of this application. Figure 13 This is a schematic diagram showing some detailed steps in an electrode manufacturing method according to an embodiment of this application. Figure 14 This is a schematic diagram illustrating some detailed steps in an electrode manufacturing method according to another embodiment of this application, with reference to... Figures 12 to 14 The third aspect of this application provides a method for manufacturing an electrode sheet 100 having a discontinuous foil structure. The structure of the electrode sheet 100 can be referred to... Figure 1 This method includes the following steps: S10: Prepare foil 101, a first slurry 300 containing a first active material and a second slurry 400 containing a second active material; S20: Multiple foils 101 are spaced apart along the first direction; S30: The first paste 300 is applied to the side of the foil 101 in the thickness direction, and the second paste 400 is applied between adjacent foils 101, and the first paste 300 and the second paste 400 are cured. S40: The cured first slurry 300 and second slurry 400 are rolled in the thickness direction of the foil 101, so that the first slurry 300 forms a first coating 102 on the side of the foil 101 in the thickness direction, and the second slurry 400 forms a second coating 103 between adjacent foils 101.

[0048] By means of the above-described electrode manufacturing method, multiple foils 101 can be spaced apart and a first coating 102 can be formed on one or both sides of the foil 101 in the thickness direction, and a second coating 103 can be formed on adjacent foils 101, thereby forming an electrode 100 with a discontinuous foil 101 structure.

[0049] In some embodiments of the electrode manufacturing method, during step S30, the first slurry 300 may be cured before the second slurry 400 is applied. For example, refer to... Figure 13 Step S30 includes: S31: Provide multiple partition plates 500, and define a first filling area 501 between adjacent foils 101 by two partition plates 500, and define a second filling area 502 between the partition plates 500 on both sides of the same foil 101, so that the first paste 300 fills the second filling area 502 and covers the side of each foil 101 in the thickness direction. S32: Allow the first slurry to solidify at 300°C; S33: The second slurry 400 is filled into the second filling area 502; S34: Remove the partition plate 500, and the second slurry 400 flows to fill the gap formed after the partition plate 500 is removed, and the second slurry 400 connects with the cured first slurry 300; S35: To cure the second slurry at 400°C.

[0050] In step S33 above, since a certain gap will be formed after the partition plate 500 is removed, when the second filling area 502 is filled with the second slurry 400, the filling height can be greater than the designed thickness of the second coating 103 along the thickness direction of the foil 101, so that the second slurry 400 flows to fill the gap formed after the partition plate 500 is removed and just reaches the designed thickness.

[0051] In some other embodiments of the electrode manufacturing method, during step S30, the second slurry 400 may be cured first before the first slurry 300 is applied. For example, refer to... Figure 14 Step 30 includes: S31': Provide a plurality of partition plates 500, and define a first filling area 501 between adjacent foils 101 by two partition plates 500, and fill the first filling area 501 with a second slurry 400. S32': After the second slurry 400 has cured, the separator 500 is removed, and a gap is formed between the second slurry 400 and the foil 101 at the location where the separator 500 has been removed; S33': The first paste 300 covers the side of each foil 101 in the thickness direction and fills the gap between the second paste 400 and the foil 101; S34': Allow the first slurry to cure at 300°C.

[0052] As can be seen from the above embodiments, the electrode manufacturing method provided in this application can produce an electrode 100 with a discontinuous foil 101 structure, a first coating 102 is formed on the side of the foil 101, and a second coating 103 is formed between adjacent foils 101. This method is applicable to manufacturing the electrode 100 of the first aspect embodiment above, and the electrode 100 can alleviate the problem of cell expansion.

[0053] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

1. An electrode, characterized in that, include: A plurality of foils are arranged at intervals along a first direction, wherein, along the first direction, the size of some of the foils is smaller than the size of the remaining foils; Multiple first coatings, each first coating comprising a first active material, wherein the first coatings are disposed on one or both sides of the foil surface along a second direction to form multiple pole segments, the second direction being perpendicular to the first direction; Multiple second coatings, each comprising a second active material, are disposed between adjacent electrode segments such that the second coatings are located between adjacent foils spaced apart, and the second coatings are connected to the foils and / or the first coating to form a continuous electrode sheet.

2. The electrode sheet according to claim 1, characterized in that, Along the first direction, the first coating is aligned with the foil.

3. The electrode sheet according to claim 1, characterized in that, Along the first direction, the foil has two opposing ends; of the plurality of foils, at least one end of a portion of the foil has a gap with the second coating.

4. The electrode sheet according to claim 3, characterized in that, Along the first direction, the foil having a gap between it and the second coating has a smaller size than the first coating.

5. The electrode sheet according to claim 3, characterized in that, The end portion includes a first end face and a second end face connected together. The first end face is in contact with the second coating, and the second end face is inclined in a direction away from the second coating. There is a gap between the second end face and the second coating.

6. The electrode sheet according to claim 1, characterized in that, Along the second direction, the thickness of the second coating is equal to the sum of the thicknesses of the foil and the first coating.

7. The electrode sheet according to any one of claims 1 to 6, characterized in that, The size of a portion of the second coating on the electrode is larger than the size of the rest of the second coating.

8. A single-cell battery, characterized in that, The battery includes a housing and a battery cell, wherein the battery cell is housed within the housing, and the battery cell comprises: Diaphragm; The electrode sheet according to any one of claims 1 to 7, wherein a plurality of the electrode sheets are stacked on top of each other, and the diaphragm is provided on both sides of each electrode sheet.

9. The single-cell battery according to claim 8, characterized in that, The electrode and the separator are wound together in a set direction to form the battery cell. The battery cell is divided into a stacking area and a bending area. In the electrode, the width of the foil corresponding to the bending area is L1, and the width of the second coating corresponding to the bending area is W1. The width of the foil corresponding to the stacked area is L2, and the width of the second coating corresponding to the stacked area is W2; Where L1 < L2, and / or W1 > W2.

10. A method for manufacturing an electrode sheet, characterized in that, The method for manufacturing the electrode sheet according to any one of claims 1 to 7 comprises: Prepare foil, a first slurry containing a first active material, and a second slurry containing a second active material; A plurality of the foils are spaced apart along a first direction; The first slurry is applied to the side of the foil in the thickness direction, and the second slurry is applied to fill the space between adjacent foils. The first slurry and the second slurry are then cured, wherein the first slurry is cured first and then the second slurry is applied, or the second slurry is cured first and then the first slurry is applied. The cured first slurry and second slurry are rolled in the thickness direction of the foil to form a first coating on the side of the foil in the thickness direction of the first slurry, and to form a second coating between adjacent foils.

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