Single-sided pole piece, laminated battery cell and battery

Abstract

The utility model provides a single-sided pole piece, a laminated cell and a battery. The single-sided pole piece comprises a current collector, a single-sided active material layer and a pole piece adhesive layer, the current collector comprises a central area and a peripheral area, the peripheral area is connected to the periphery of the central area, the single-sided active substance layer is arranged on one side of the current collector and covers the central area, the pole piece adhesive layer and the single-sided active substance layer are located on the same side of the current collector, and the pole piece adhesive layer covers the peripheral area. And the pole piece adhesive layer is used for being bonded with a diaphragm in the laminated battery cell. The risk that the edge of the single-sided pole piece is curled and warped is relatively low, and the risk of lithium precipitation of a battery cell is reduced.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a single-sided electrode, a stacked cell, and a battery. Background Technology

[0002] In existing technologies, the outermost two electrodes of a laminated battery cell are typically single-sided electrodes, while the remaining electrodes are double-sided electrodes. A single-sided electrode is one with an active material layer on only one side, while a double-sided electrode has an active material layer on both sides. For single-sided electrodes, the stress on the two sides of the current collector is uneven, making them prone to curling and warping. This not only affects the safety performance of the battery cell but also reduces its cycle performance. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a single-sided electrode sheet with a lower risk of edge curling or warping.

[0004] This invention also provides a stacked cell and a battery comprising the aforementioned stacked cell.

[0005] A single-sided electrode sheet according to a first aspect of the present invention includes: a current collector including a central region and a peripheral region, the peripheral region being connected to the periphery of the central region; a single-sided active material layer disposed on one side of the current collector and covering the central region; and an electrode adhesive layer located on the same side of the current collector as the single-sided active material layer, the electrode adhesive layer covering the peripheral region, and the electrode adhesive layer being used for bonding with a separator in a laminated battery cell.

[0006] The single-sided electrode sheet according to the first aspect of the present invention has at least the following beneficial effects:

[0007] Because the peripheral area of ​​the current collector of the single-sided electrode is provided with an electrode adhesive layer, the peripheral area can be bonded to the diaphragm. The adhesive force between the peripheral area and the diaphragm can prevent the edge of the single-sided electrode from curling, thereby reducing the risk of the edge of the single-sided electrode curling or lifting.

[0008] Furthermore, existing technologies typically employ increasing the thickness of the current collector in a single-sided electrode to overcome its stress and prevent warping. However, this design leads to a higher current density in the current collector, making lithium plating more likely on the corresponding negative electrode when the single-sided electrode is the positive electrode. This invention employs a completely different concept. It adds an electrode adhesive layer to the outer region without increasing the thickness of the current collector, thus avoiding excessive current density and reducing the risk of lithium plating.

[0009] According to some embodiments of the present invention, the peripheral region includes a first sub-region, a second sub-region, and a third sub-region. The first sub-region is located at one end of the single-sided active material layer in a first direction, and the other end edge of the single-sided active material layer in the first direction coincides with the end edge of the central region away from the first sub-region. The second sub-region and the third sub-region are respectively located at both ends of the single-sided active material layer in a second direction, and any two of the first direction, the second direction, and the thickness direction of the single-sided electrode are perpendicular to each other.

[0010] According to some embodiments of the present invention, the size of the first sub-region in the first direction is H1, 0.6mm≤H1≤1.8mm; and / or, the size of the second sub-region in the second direction is H2, 0.4mm≤H2≤1.2mm; and / or, the size of the third sub-region in the second direction is H3, 0.4mm≤H3≤1.2mm.

[0011] According to a second aspect embodiment of the present invention, a stacked battery cell includes a separator, a plurality of first electrodes and a plurality of second electrodes, wherein one of the first electrodes and the second electrodes is a positive electrode and the other is a negative electrode. The first electrodes, the second electrodes and the separator are stacked on top of each other, and the separator separates the first electrodes and the second electrodes. In the thickness direction of the stacked battery cell, two first electrodes located at both ends of the stacked battery cell are single-sided electrodes. Each single-sided electrode includes: a current collector, including a central region and a peripheral region, wherein the peripheral region is connected to the periphery of the central region; a single-sided active material layer, wherein the single-sided active material layer is disposed on one side of the current collector and covers the central region; and an electrode adhesive layer, wherein the electrode adhesive layer and the single-sided active material layer are located on the same side of the current collector, the electrode adhesive layer covers the peripheral region, and the electrode adhesive layer is bonded to the separator.

[0012] According to some embodiments of the present invention, the outer edge of the diaphragm is located outside the outer edge of the second electrode. For any single-sided electrode and an adjacent second electrode, the outer edge of the peripheral region is located outside the outer edge of the second electrode, and the outer edge of the second electrode is located outside the outer edge of the central region.

[0013] According to some embodiments of the present invention, the single-sided electrode further includes a first tab region, and the peripheral region includes a first sub-region, a second sub-region, and a third sub-region. The first sub-region and the first tab region are respectively located at both ends of the single-sided electrode in the first direction. The edge of the single-sided active material layer away from the first sub-region coincides with the edge of the central region away from the first sub-region. The second sub-region and the third sub-region are respectively located at both ends of the stacked cell in the second direction. Any two of the first direction, the second direction, and the thickness direction of the stacked cell are perpendicular to each other.

[0014] According to some embodiments of the present invention, the diaphragm is folded and includes multiple layers of partitions, and a partition is provided between any one of the first electrode sheets and an adjacent second electrode sheet; the portion of the partition located outside the outer edge of the second electrode sheet is an adhesive area, and in the thickness direction of the stacked cell, each electrode sheet adhesive layer is bonded to an adjacent adhesive area.

[0015] According to some embodiments of the present invention, in the thickness direction of the laminated battery cell, two adjacent bonding areas are bonded to each other.

[0016] According to some embodiments of the present invention, the first electrode is a positive electrode.

[0017] The battery according to a third aspect embodiment of the present invention includes the battery cell as described in the second aspect embodiment.

[0018] Additional aspects and advantages of this invention 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 the invention. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0020] Figure 1 This is a planar schematic diagram of a single-sided electrode sheet in one embodiment of the present invention;

[0021] Figure 2 This is a planar schematic diagram of a current collector for a single-sided electrode.

[0022] Figure 3 This is an isometric view of a stacked battery cell according to an embodiment of the present invention;

[0023] Figure 4 This is a cross-sectional view of a laminated battery cell.

[0024] Reference numerals: 101-Current collector, 102-Central region, 103-Outer region, 104-Second sub-region, 105-First sub-region, 106-Third sub-region, 107-First tab region, 108-Single-sided active material layer, 109-Cell body, 110-First tab assembly, 111-Second tab assembly, 112-Laminated cell, 113-Single-sided electrode, 114-First electrode, 115-Second electrode, 116-First double-sided electrode, 117-Separator, 118-Electrode adhesive layer, 120-Separator section. Detailed Implementation

[0025] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0026] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0027] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0028] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0029] Figure 1 This invention illustrates a single-sided electrode 113 according to an embodiment of the present invention. The single-sided electrode 113 includes a current collector 101, a single-sided active material layer 108, and an electrode adhesive layer 118 (the electrode adhesive layer 118 is not on the electrode). Figure 1 (As shown in the figure). In the laminated cell 112, the single-sided electrode 113 is usually located at both ends in the thickness direction of the laminated cell 112 (e.g., Figure 4 (As shown). Figure 2A current collector 101 for a single-sided electrode 113 is shown. The current collector 101 includes a central region 102 and a peripheral region 103, with the peripheral region 103 connected to the periphery of the central region 102. The current collector 101 can be a metal foil. For example, if the single-sided electrode 113 is a positive electrode, the current collector 101 is aluminum foil; if the single-sided electrode 113 is a negative electrode, the current collector 101 is copper foil. A single-sided active material layer 108 covers the central region 102, and an electrode adhesive layer 118 covers the peripheral region 103. The single-sided active material layer 108 is disposed on one side of the current collector 101, and the electrode adhesive layer 118 and the single-sided active material layer 108 are located on the same side of the current collector 101. The electrode adhesive layer 118 is used to bond to the separator 117 in the laminated cell 112. Since the peripheral area 103 of the current collector 101 is provided with an electrode adhesive layer 118, the edge area of ​​the single-sided electrode 113 can be bonded and fixed with the diaphragm 117, thereby preventing the edge area of ​​the single-sided electrode 113 from curling or lifting relative to the diaphragm 117.

[0030] like Figure 2 As shown, in one embodiment, the peripheral region 103 includes a first sub-region 105, a second sub-region 104, and a third sub-region 106. The two ends of the first sub-region 105 are connected to the second sub-region 104 and the third sub-region 106, respectively. The first sub-region 105 is located at one end of the single-sided active material layer 108 in a first direction, and the edge of the other end of the single-sided active material layer 108 in the first direction coincides with the edge of the central region 102. For example, if the first direction is a front-to-back direction, the first sub-region 105 is located at the rear end of the single-sided active material layer 108, and the front edge of the single-sided active material layer 108 coincides with the front edge of the central region 102. The current collector 101 also includes a first tab region 107, which is connected to one end of the central region 102 in the first direction. For example, the first tab region 107 is connected to the front edge of the central region 102. The second sub-region 104 and the third sub-region 106 are located at opposite ends of the single-sided active material layer 108 in the second direction, respectively, and any two of the first direction, the second direction, and the thickness direction of the single-sided electrode 113 are perpendicular to each other. For example, in Figure 1 and Figure 2 In this design, the thickness direction of the single-sided electrode 113 is perpendicular to the paper surface, and the second direction is left-right. The second sub-region 104 and the third sub-region 106 are located at the left and right ends of the single-sided active material layer 108, respectively. This arrangement allows the outer region 103 to surround three sides of the single-sided active material layer 108, increasing the area of ​​the electrode adhesive layer 118, thereby improving the adhesion between the single-sided electrode 113 and the separator 117 and reducing the risk of edge lifting of the single-sided electrode 113.

[0031] like Figure 1As shown, the first sub-region 105 has a dimension of H1 in the first direction, the second sub-region 104 has a dimension of H2 in the second direction, and the third sub-region 106 has a dimension of H3 in the third direction. In some embodiments, H1 satisfies 0.6mm ≤ H1 ≤ 1.8mm. H1 not less than 0.6mm helps prevent the bonding area between the rear end of the single-sided electrode 113 and the separator 117 from being too small, thereby helping to prevent the rear end of the single-sided electrode 113 from curling or lifting. H1 not greater than 1.8mm helps prevent the central region 102 from being too small, thereby preventing the area of ​​the single-sided active material layer 108 from being too small, and thus preventing the cell capacity from being too low. Similarly, in order to balance the anti-lifting effect and the cell capacity, H2 can satisfy 0.4mm ≤ H2 ≤ 1.2mm, and H3 can satisfy 0.4mm ≤ H3 ≤ 1.2mm.

[0032] Figure 3 A stacked battery cell 112 according to one embodiment of the present invention is shown. The stacked battery cell 112 includes a separator 117, a plurality of first electrodes 114, and a plurality of second electrodes 115. The first electrodes 114, second electrodes 115, and separator 117 are stacked on top of each other, and the separator 117 separates the first electrodes 114 and the second electrodes 115. For example, only one separator 117 is provided, the separator 117 is folded, and the separator 117 includes multiple layers of separators 120. A separator 120 is provided between any one first electrode 114 and a second electrode 115 adjacent to that first electrode 114. As another example, in some embodiments not shown, the stacked battery cell 112 includes multiple separators 117, and a single separator 117 is provided between any one first electrode 114 and a second electrode 115 adjacent to it. In the thickness direction of the laminated cell 112, the two first electrode plates 114 located at both ends of the laminated cell 112 are both single-sided electrode plates 113. The specific structure of the single-sided electrode plate 113 has been introduced above and will not be repeated here.

[0033] All the second electrodes 115 and the remaining first electrodes 114 are double-sided electrodes, meaning that each electrode has an active material layer on each side. It should be noted that the active material of the first electrode 114 is different from that of the second electrode 115. For example, the first electrode 114 is a positive electrode, and the second electrode 115 is a negative electrode. The active material of the first electrode 114 can include lithium cobalt oxide, ternary lithium, lithium iron phosphate, etc., while the active material of the second electrode 115 can include graphite.

[0034] One of the first electrode 114 and the second electrode 115 is a positive electrode, and the other is a negative electrode. Figure 4In the illustrated embodiment, the first electrode 114 is the positive electrode, and the second electrode 115 is the negative electrode. Placing the positive electrode on the outermost layer of the stacked cell 112 is beneficial for improving the performance of the cell. For example, the active material of the positive electrode has relatively low chemical activity, making it less prone to self-discharge when in contact with ambient air compared to the negative electrode. Furthermore, during the charging and discharging process of the stacked cell 112, both the positive and negative electrodes undergo volume changes. The negative electrode experiences relatively larger volume changes during lithium-ion insertion and extraction, while the positive electrode experiences relatively smaller volume changes. Placing the positive electrode on the outermost layer better maintains the stability of the cell structure and extends the battery's cycle life.

[0035] like Figure 2 As shown, the first electrode 114 also includes a first tab region 107, which is connected to one end of the central region 102 in a first direction. Each first electrode 114 includes a first tab region 107, and multiple first tab regions 107 belonging to different first electrode 114 are stacked and welded (or bonded) to each other to form a first tab assembly 110. Similarly, the second electrode 115 includes a second tab region, and the formation of the second tab assembly 111 is similar to that of the first tab, which will not be described in detail here. The above arrangement allows electrons to quickly enter or leave the electrode layers from the tab assembly, thereby helping to reduce the internal resistance of the stacked cell 112 and improve the charging and discharging efficiency of the stacked cell 112.

[0036] like Figure 1 As shown, since the edge of the single-sided active material layer 108 away from the first sub-region 105 coincides with the edge of the central region 102 away from the first sub-region 105, and the first tab region 107 and the first sub-region 105 are located at the two ends of the single-sided electrode 113 in the first direction, the distance between the first tab region 107 and the single-sided active material layer 108 is relatively close. This is beneficial for electrons to quickly enter or leave the electrode from the first tab region 107, thereby helping to reduce the internal resistance of the stacked cell 112 and improve the charging and discharging efficiency of the stacked cell 112.

[0037] The portion of the separator 120 located outside the outer edge of the second electrode 115 is the bonding area. For example, as... Figure 4As shown, the dimension of the separator 120 in the left-right direction is larger than that of the second electrode 115 in the left-right direction. The left edge of the separator 120 protrudes to the left relative to the left edge of the second electrode 115, and the right edge of the separator 120 protrudes to the right relative to the right edge of the second electrode 115. The bonding area includes the portion of the separator 120 that protrudes to the left relative to the second electrode 115 and the portion of the separator 120 that protrudes to the right relative to the second electrode 115. Other side edges of the separator 120 may also protrude relative to the second electrode 115. For example, the front edge of the separator 120 protrudes forward relative to the front edge of the second electrode 115, and the rear edge of the separator 120 protrudes backward relative to the rear edge of the second electrode 115. The bonding area also includes the portion of the separator 120 that protrudes forward and the portion that protrudes backward relative to the second electrode 115.

[0038] In the thickness direction of the laminated cell 112, each electrode adhesive layer 118 is bonded to an adjacent bonding area. For example, with Figure 4 For example, for the top single-sided electrode 113, its electrode adhesive layer 118 is bonded to an adjacent lower partition 120, and to the portion of the partition 120 located outside the outer edge of the second electrode 115 (i.e., the bonding area). This arrangement allows the edge region of the single-sided electrode 113 to bond together with the edge region of the diaphragm 117, reducing the risk of the single-sided electrode 113 curling or lifting.

[0039] In some embodiments, in the thickness direction of the laminated cell 112, two adjacent bonding regions are bonded to each other, and these two bonding regions belong to the separators 120 of different layers. For example, the surface of the bonding region is provided with a separator 117 adhesive layer (not shown), and two adjacent bonding regions are bonded by the separator 117 adhesive layer. Since the adjacent bonding regions are also bonded to each other, the peripheral region 103 of the single-sided electrode 113 and the multilayer separators 120 are bonded as a whole, which helps to further reduce the risk of curling and warping of the single-sided electrode 113.

[0040] This utility model also provides a battery, which may include the laminated cell 112 in any of the above embodiments. In some embodiments, the battery may be a pouch battery, and the battery may also include an aluminum-plastic film, in which the laminated cell 112 is encapsulated. In other embodiments, the battery casing may also be a hard shell made of metal materials such as aluminum alloy or steel, in which the laminated cell 112 is encapsulated.

[0041] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A single-sided electrode, characterized in that, include: The current collector includes a central area and a peripheral area, wherein the peripheral area is connected to the periphery of the central area; A single-sided active material layer is disposed on one side of the current collector and covers the central area; An electrode adhesive layer is located on the same side of the current collector as the single-sided active material layer. The electrode adhesive layer covers the peripheral area and is used to bond with the separator in the stacked battery cell.

2. The single-sided electrode according to claim 1, characterized in that, The peripheral region includes a first sub-region, a second sub-region, and a third sub-region. The first sub-region is located at one end of the single-sided active material layer in a first direction. The other end edge of the single-sided active material layer in the first direction coincides with the edge of the central region away from the first sub-region. The second sub-region and the third sub-region are located at opposite ends of the single-sided active material layer in a second direction. Any two of the first direction, the second direction, and the thickness direction of the single-sided electrode are perpendicular to each other.

3. The single-sided electrode sheet according to claim 2, characterized in that, The dimension of the first sub-region in the first direction is H1, where 0.6mm ≤ H1 ≤ 1.8mm; And / or, the dimension of the second sub-region in the second direction is H2, 0.4mm≤H2≤1.2mm; And / or, the dimension of the third sub-region in the second direction is H3, 0.4mm≤H3≤1.2mm.

4. A laminated battery cell, characterized in that, It includes a separator, a plurality of first electrodes and a plurality of second electrodes, one of the first electrodes and the other of the second electrodes being a positive electrode and the other being a negative electrode. The first electrodes, the second electrodes and the separator are stacked on top of each other, and the separator separates the first electrodes and the second electrodes. In the thickness direction of the laminated battery cell, the two first electrodes located at both ends of the laminated battery cell are single-sided electrodes, and the single-sided electrodes include: The current collector includes a central area and a peripheral area, wherein the peripheral area is connected to the periphery of the central area; A single-sided active material layer is disposed on one side of the current collector and covers the central area; An electrode adhesive layer is provided, wherein the electrode adhesive layer and the single-sided active material layer are located on the same side of the current collector, the electrode adhesive layer covers the peripheral area, and the electrode adhesive layer is bonded to the diaphragm.

5. The laminated cell according to claim 4, characterized in that, The outer edge of the diaphragm is located outside the outer edge of the second electrode. For any single-sided electrode and an adjacent second electrode, the outer edge of the peripheral region is located outside the outer edge of the second electrode, and the outer edge of the second electrode is located outside the outer edge of the central region.

6. The laminated cell according to claim 4, characterized in that, The single-sided electrode further includes a first tab region, and the peripheral region includes a first sub-region, a second sub-region, and a third sub-region. The first sub-region and the first tab region are located at both ends of the single-sided electrode in a first direction. The edge of the single-sided active material layer away from the first sub-region coincides with the edge of the central region away from the first sub-region. The second sub-region and the third sub-region are located at both ends of the stacked cell in a second direction. Any two of the first direction, the second direction, and the thickness direction of the stacked cell are perpendicular to each other.

7. The laminated cell according to claim 4, characterized in that, The diaphragm is folded and includes multiple partitions, with one partition between any one of the first electrode plates and an adjacent second electrode plate. The portion of the separator located outside the outer edge of the second electrode is the bonding area. In the thickness direction of the stacked cell, each electrode adhesive layer is bonded to an adjacent bonding area.

8. The laminated cell according to claim 7, characterized in that, In the thickness direction of the laminated cell, two adjacent bonding areas are bonded to each other.

9. The laminated cell according to claim 4, characterized in that, The first electrode is a positive electrode.

10. A battery, characterized in that, Includes laminated cells as described in any one of claims 4 to 9.

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