Anti-sodium precipitation winding type battery cell, battery and electric device

Abstract

The application discloses a sodium precipitation prevention winding type battery cell, a battery and an electric device. The sodium precipitation prevention winding type battery cell comprises a winding core, the winding core is formed by winding a positive electrode sheet, a diaphragm and a negative electrode sheet, the diaphragm is located between the positive electrode sheet and the negative electrode sheet, the surface of the winding core has a flat area and a corner area, the positive electrode sheet comprises a positive electrode current collector, a positive electrode active layer and an electrical conductivity regulation layer, the electrical conductivity regulation layer is located on the side of the positive electrode active layer close to and away from the center of the winding core, and the ion conductivity of the electrical conductivity regulation layer is lower than that of the positive electrode active layer; the electrical conductivity regulation layer comprises a base layer and a viscous layer, the base layer has a sodium ion transmission channel, and the viscous layer is arranged on the side of the base layer close to the positive electrode active layer. The sodium precipitation prevention winding type battery cell can not only effectively avoid sodium precipitation and prolong the service life, but also is convenient to set and simple in process.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a sodium-resistant wound battery cell, battery, and electrical device. Background Technology

[0002] During the charging and discharging process of sodium-ion battery wound cells, sodium deposition can easily occur at the R-corner positions of the innermost 1 to 5 layers of the negative electrode due to excessive local accumulation of sodium ions. This leads to cell capacity decay, increased internal resistance, and the risk of dendrites piercing the separator. Existing solutions (such as adjusting the electrolyte formula and optimizing the charging method) have problems such as complex processes or limited effectiveness. Utility Model Content

[0003] One objective of this application is to provide a sodium-resistant wound battery cell that can at least solve the technical problem that sodium deposition easily occurs at the corner positions of existing wound battery cells.

[0004] Another object of this application is to provide a battery including the above-mentioned anti-sodium-deposition wound cell.

[0005] Another object of this application is to provide an electrical device including the aforementioned battery.

[0006] To achieve the above objectives, this application provides the following technical solutions.

[0007] According to an embodiment of the first aspect of this application, a sodium-resistant wound battery cell includes: a core formed by winding a positive electrode sheet, a separator, and a negative electrode sheet, wherein the separator is located between the positive and negative electrode sheets, and the surface of the core has a flat region and a corner region. The positive electrode sheet includes a positive current collector, a positive active layer, and a conductivity control layer. The conductivity control layer is located on the side of the positive active layer in the corner region that is close to and away from the center of the core, and the ionic conductivity of the conductivity control layer is lower than that of the positive active layer. The conductivity control layer includes: a substrate layer having sodium ion transport channels; and an adhesive layer disposed on the side of the substrate layer close to the positive active layer.

[0008] Optionally, the ionic conductivity of the conductivity modulation layer is 10. -5 S / cm-10 -3 S / cm.

[0009] Optionally, the substrate layer is composed of Na3Zr2Si2PO4. 12 The filler consists of a polymer matrix layer, a sodium-treated ceramic coating composite layer, or a nonwoven fabric layer.

[0010] Optionally, the thickness of the substrate layer is 10um-50um.

[0011] Optionally, the adhesive layer is a hypoallergenic adhesive layer, a polyurethane adhesive layer, an epoxy resin adhesive layer, or a silicone adhesive layer, and / or the thickness of the adhesive layer is 5µm-15µm.

[0012] Optionally, the orthographic projection of the conductivity modulation layer on the positive electrode sheet overlaps the orthographic projection of the corner region on the positive electrode sheet.

[0013] Optionally, in the winding direction, at least one end of the conductivity control layer extends beyond the corner region by 1 mm to 3 mm.

[0014] Optionally, in the winding direction, the width of the corner region is 1mm-10mm.

[0015] A battery according to a second aspect of this application includes: a housing, wherein an electrolyte is injected into the housing; and a battery cell according to any of the above embodiments, wherein the battery cell is installed in the housing.

[0016] The electrical device according to the third aspect of this application includes any of the batteries described above.

[0017] According to the embodiments of this application, the anti-sodium-deposition wound battery cell can reduce the ionic conductivity of the positive electrode in the corner region through the conductivity control layer. In addition, the conductivity control layer includes a substrate layer and an adhesive layer, which has the advantages of being easy to process and simple in process.

[0018] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the present application and, together with their description, serve to explain the principles of the present application.

[0020] Figure 1 This is a schematic diagram of the winding of a core according to an embodiment of this application;

[0021] Figure 2 This is a schematic diagram of the interaction between the conductivity control layer and the positive electrode sheet according to an embodiment of this application;

[0022] Figure 3 This is a partial structural schematic diagram of the positive electrode sheet according to an embodiment of this application.

[0023] Attached icon number

[0024] 100 anti-sodium-deposition wound battery cells;

[0025] Positive electrode 10; First surface 11; Second surface 12; Separator 20; Negative electrode 30; Corner region 40; Conductivity control layer 50. Detailed Implementation

[0026] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated 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 application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0027] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0028] In the description of this application, it should be understood that the terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or element 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.

[0029] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0030] The following describes in detail, with reference to the accompanying drawings, an embodiment of the anti-sodium-deposition wound battery cell 100 according to the present application.

[0031] like Figures 1 to 3 As shown, the anti-sodium-deposition wound battery cell 100 according to an embodiment of this application includes: a wound core.

[0032] Specifically, the core is formed by winding a positive electrode 10, a separator 20, and a negative electrode 30. The separator 20 is located between the positive electrode 10 and the negative electrode 30. The surface of the core has a flat region and a corner region 40. The positive electrode 10 includes a positive current collector, a positive active layer, and a conductivity control layer 50. The conductivity control layer 50 is located on the side of the positive active layer in the corner region 40, near and away from the center of the core. The ionic conductivity of the conductivity control layer 50 is lower than that of the positive active layer. The conductivity control layer 50 includes a substrate layer and an adhesive layer. The substrate layer has sodium ion transport channels, and the adhesive layer is located on the side of the substrate layer near the positive active layer.

[0033] In other words, the anti-sodium-deposition wound battery cell 100 according to the embodiments of this application mainly includes a core, which is formed by winding a positive electrode 10, a separator 20, and a negative electrode 30 in the same direction, with the separator 20 located between the positive electrode 10 and the negative electrode 30. For example Figure 1 In the diagram, A represents the negative electrode 30, C represents the positive electrode 10, the dashed line between A and C represents the diaphragm 20, and the solid black area represents the corner area 40.

[0034] The positive electrode 10 and the negative electrode 30 each include a current collector and an active layer located on both sides of the current collector. For example, the positive electrode 10 includes a positive current collector, on which a positive active layer is disposed. The positive active layer is formed by coating a positive electrode slurry onto the positive current collector, and the thickness of the positive active layer is 50µm-300µm. The positive active slurry includes a layered oxide as the main positive active material, an organic solvent, a binder, a conductive agent, etc. Except for the organic solvent, the layered oxide accounts for 90%-99%, the binder accounts for 0.5%-5%, and the conductive agent accounts for 0.5%-5%. The positive current collector is an aluminum foil with a thickness of 6µm-15µm. For example, the negative electrode sheet 30 includes a negative electrode current collector; a negative electrode active layer is disposed on the negative electrode current collector, which is formed by coating the negative electrode slurry onto the negative electrode current collector, and the thickness of the negative electrode active layer is 60um-350um; the negative electrode active slurry includes the main negative electrode active material hard carbon or soft carbon, organic or inorganic solvents, binders, conductive agents, etc.; except for the solvent, hard carbon or soft carbon accounts for 90%-98%, binder accounts for 1%-5%, and conductive agent accounts for 0.5%-5%; the negative electrode current collector can be copper foil or aluminum foil; using aluminum foil is cheaper, and the thickness of the negative electrode current collector is 2um-15um. Another example is that the substrate material of the separator is PE, PP, PE / PP composite separator, aramid, and other materials; one or both sides of the separator can be coated with ceramic particles such as alumina (Al2O3) and silicon dioxide (SiO2) and adhesive layers such as PVDF.

[0035] Furthermore, the core includes a flat region and a corner region 40. Conductivity control layers 50 are provided on both sides of the positive electrode 10 located in the corner region 40. For ease of explanation, the side of the positive electrode 10 in the corner region 40 that is closer to the center of the core can be defined as the first surface 11, and the side that is farther away from the center of the core can be defined as the second surface 12. That is, the first surface 11 and the second surface 12 are respectively provided with conductivity control layers 50.

[0036] It is understandable that the positive electrode corner of the wound cell (especially the area corresponding to the inner R-angle of the negative electrode) experiences an "ion flow focusing effect" during charging and discharging: due to the geometric constraints of the winding structure, the current density at the positive electrode corner can reach 1.5 to 2 times that of the planar area, resulting in an excessively fast sodium ion extraction rate and the formation of a localized high-concentration ion flow. In this embodiment, the ionic conductivity of the conductivity control layer 50 is lower than that of the positive electrode active layer. Therefore, it can reduce the ionic conductivity of the positive electrode plate 10 in the corner region, slowing down the rate at which sodium ions are extracted from the positive electrode, allowing the ion flow to be uniformly directed towards the negative electrode, and preventing sodium deposition due to excessive ion accumulation at the inner R-angle of the negative electrode. In other words, after the conductivity of the positive electrode corner is reduced, the sodium ion flux flowing to the inner R-angle of the negative electrode decreases. Therefore, the conductivity control layer 50 of this embodiment can solve the problem of sodium deposition caused by uneven ion concentration at the inner R-angle of the negative electrode.

[0037] In addition, the conductivity control layer 50 includes a substrate layer and an adhesive layer. The substrate layer has sodium ion transport channels, and the substrate layer can be disposed on the surface of the positive electrode active layer through the adhesive layer. During the fabrication of the conductivity control layer 50, it can be adhered to the first surface 11 and the second surface 12 areas by an adhesive bonding mechanism during the winding process of the core.

[0038] Therefore, the anti-sodium-deposition wound battery cell 100 according to the embodiments of this application can reduce the ionic conductivity of the positive electrode 10 in the corner region through the conductivity control layer 50. On the other hand, the conductivity control layer 50 includes a substrate layer and an adhesive layer, which has the advantages of being easy to process and simple in process.

[0039] According to one embodiment of this application, the ionic conductivity of the conductivity modulation layer 50 is 10. -5 S / cm-10 -3 S / cm, which is understandable, is because the ionic conductivity of conventional positive electrode active materials is approximately 10. -3 In this embodiment, by employing an ionic conductivity within the aforementioned range, for example, the ionic conductivity of the conductivity control layer 50 is 10 S / cm. -5 S / cm, 10 -4.5 S / cm, 10 -4 S / cm, 10 -3.5 S / cm or 10 -3A gradient difference of S / cm can be formed, which can not only avoid excessive ion transport resistance, but also ensure significant ion flow regulation effect.

[0040] According to one embodiment of this application, the substrate layer is a Na3Zr2Si2PO4 substrate. 12 The polymer matrix layer, sodium-treated ceramic coating composite material layer, or non-woven fabric material layer of the filler can be flexibly selected according to design requirements. It should be noted that the Na3Zr2Si2PO4-containing filler in this embodiment... 12 The polymer matrix layer, the sodium-treated ceramic coating composite layer, or the nonwoven fabric layer of the filler are all existing materials. Among them, Na3Zr2Si2PO 12 It belongs to the zirconium-based phosphate compounds and typically has a NASICON (sodium superionic conductor) structure. At room temperature, Na₃Zr₂Si₂PO₄ 12 Sodium ions have high conductivity and good chemical and thermal stability. (Na3Zr2Si2PO4) 12 The polymer matrix layer of the filler can be PEO / Na3Zr2Si2PO 12 System, PVDF-HFP / Na3Zr2Si2PO 12 In addition to the above, the matrix layer can also be made of PF, PDMS, EP, etc. Sodium-treated ceramic coating composite layers are a type of functional material system that optimizes performance by introducing sodium ions (Na⁺). They combine the high temperature resistance and corrosion resistance of ceramic coatings with the sodium ion conduction / storage functions. Sodium treatment can enhance ion conduction and regulate interfacial activity. For example, sodium-treated ceramic coating composite layers are sodium montmorillonite (Na-MMT) coatings, sodium titanate (Na₂Ti₃O₇) coatings, etc.

[0041] In some specific embodiments of this application, the thickness of the substrate layer is 10um-50um, for example, the thickness of the substrate layer is 10um, 12um, 15um, 20um, 30um, 35um, 40um or 50um, which can avoid the substrate layer being too thick.

[0042] In some specific embodiments of this application, the adhesive layer is a hypoallergenic adhesive layer, a polyurethane adhesive layer, an epoxy resin adhesive layer, or an organosilicon adhesive layer, which can play a good adhesive role, and / or the thickness of the adhesive layer is 5um-15um, such as 5um, 6um, 8um, 10um, 12um, 13um, 14um, or 15um, which can avoid the adhesive layer being too thick.

[0043] According to one embodiment of this application, the orthogonal projection of the conductivity control layer 50 on the positive electrode 10 covers the orthogonal projection of the corner region 40 on the positive electrode 10. That is, the area of ​​the conductivity control layer 50 is not less than the area of ​​the corner region 40 and covers the corner region 40, which can further reduce the risk of sodium deposition at the inner circle R corner of the negative electrode.

[0044] In some specific embodiments of this application, in the winding direction, at least one end of the conductivity control layer 50 extends beyond the corner region 40 by a distance of 1mm-3mm. For example, the left end of the conductivity control layer 50 extends beyond the left end of the corner region 40 by 1mm-3mm, and the right end of the conductivity control layer 50 extends beyond the right end of the corner region 40 by 1mm-3mm. Figure 2 As shown, the width of the corner region 40 is D, and the distance by which the end edge of the conductivity control layer 50 extends beyond the wide side of the corner region 40 is d. In this embodiment, in the winding direction, at least one end of the conductivity control layer 50 extends beyond the corner region 40 by a distance of 1mm-3mm, for example, 1mm, 1.2mm, 1.5mm, 2mm, 2.5mm, or 3mm. Since the capacity is generated by the conduction of active ions from the positive electrode to the negative electrode, in this embodiment, by adopting the above range, it is beneficial to ensure the capacity utilization rate of the conductivity control layer 50.

[0045] According to one embodiment of this application, in the winding direction, the width of the corner region 40 is 1mm-10mm, for example, the width of the corner region 40 is 1mm, 2mm, 4mm, 5mm, 6mm, 8mm or 10mm, which helps to reduce the difficulty of generating the corner region 40 when winding the battery cell.

[0046] This application also discloses a battery, including: a casing and a battery cell, wherein the battery cell is the battery cell according to any of the above embodiments, an electrolyte is injected into the casing, and the battery cell is installed inside the casing. Since the battery of the embodiments of this application includes a battery cell, and the battery cell can regulate the ion transport in the corner region 40 to solve the technical problem of sodium precipitation, the battery of this application also has the above advantages, which will not be elaborated here.

[0047] This application also discloses an electrical device including the battery of any of the above embodiments. Since the battery of the embodiments of this application has the advantages of simple process and long battery life, and the electrical device of the embodiments of this application includes the above-mentioned battery, it also has the same advantages, which will not be elaborated here.

[0048] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. 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.

[0049] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A sodium-resistant wound battery cell (100), characterized in that, include: The core is formed by winding a positive electrode sheet (10), a separator (20) and a negative electrode sheet (30). The separator (20) is located between the positive electrode sheet (10) and the negative electrode sheet (30). The surface of the core has a flat area and a corner area (40). The positive electrode sheet (10) includes a positive current collector, a positive active layer and a conductivity control layer (50). The conductivity control layer (50) is located on the side of the corner area (40) of the positive active layer near and away from the center of the core. The ionic conductivity of the conductivity control layer (50) is lower than that of the positive active layer. The conductivity modulation layer (50) includes: A substrate layer having sodium ion transport channels; An adhesive layer is disposed on the side of the substrate layer near the positive electrode active layer.

2. The anti-sodium-deposition wound battery cell (100) according to claim 1, characterized in that, The ionic conductivity of the conductivity modulation layer (50) is 10. -5 S / cm-10 -3 S / cm.

3. The anti-sodium-deposition wound battery cell (100) according to claim 1, characterized in that, The substrate layer is composed of Na3Zr2Si2PO4. 12 The filler consists of a polymer matrix layer, a sodium-treated ceramic coating composite layer, or a nonwoven fabric layer.

4. The anti-sodium-deposition wound battery cell (100) according to claim 1, characterized in that, The thickness of the substrate layer is 10um-50um.

5. The anti-sodium-deposition wound battery cell (100) according to claim 1, characterized in that, The adhesive layer is a hypoallergenic adhesive layer, a polyurethane adhesive layer, an epoxy resin adhesive layer, or a silicone adhesive layer; and / or, the thickness of the adhesive layer is 5µm-15µm.

6. The anti-sodium-deposition wound battery cell (100) according to claim 1, characterized in that, The orthographic projection of the conductivity control layer (50) on the positive electrode (10) covers the orthographic projection of the corner region (40) on the positive electrode (10).

7. The anti-sodium-deposition wound battery cell (100) according to claim 6, characterized in that, In the winding direction, at least one end of the conductivity control layer (50) extends beyond the corner region (40) by 1 mm-3 mm.

8. The anti-sodium-deposition wound battery cell (100) according to claim 1 or 7, characterized in that, In the winding direction, the width of the corner region (40) is 1mm-10mm.

9. A battery, characterized in that, include: A housing, wherein an electrolyte is injected into the housing; The battery cell according to any one of claims 1-8 is installed inside the housing.

10. An electrical appliance, characterized in that, Includes the battery as described in claim 9.

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