Anode strip, battery and electric equipment

Abstract

The utility model discloses an anode strip, a battery and electric equipment, and the anode strip comprises a current collector, a lithium supplementing layer and a protective layer. The anode strip has a set thickness, and the current collector has a first surface and a second surface which are back to back along the thickness direction of the anode strip; the active material layers are located on the first surface and the second surface, and at least one of the active material layer located on the first surface and the active material layer located on the second surface is provided with a containing groove sunken towards the current collector; the inner wall face of the containing groove is covered with a lithium supplementing layer. And a protective layer covers the outer surface of the lithium supplementing layer and is used for limiting lithium powder in the lithium supplementing layer in the accommodating groove. Therefore, lithium powder dissociation in the lithium supplementing layer is reduced, and dust and scraps are reduced, so that when the anode strip is used for the battery, the K value of the battery can be reduced, and the use performance of the battery is improved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to an anode sheet, a battery, and an electrical device. Background Technology

[0002] Increasing the thickness of the anode sheet can increase the loading of active materials and reduce the proportion of inactive components, thereby improving the battery's energy density. However, increasing the anode sheet thickness lengthens the lithium-ion transport path, increasing battery impedance and leading to poor rate performance and electrode reaction kinetics. To address this, some technologies incorporate containment grooves within the anode active material layer to shorten the lithium-ion transport path. Simultaneously, to maintain battery energy density, a lithium replenishment layer is placed within the containment groove. However, directly placing a lithium replenishment layer within the containment groove can easily lead to lithium-ion ionization, increasing the battery's K-value. 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 an anode sheet that can be used in batteries to reduce the K-value of the battery.

[0004] This invention also provides a battery comprising the aforementioned anode plate.

[0005] This utility model also provides an electrical device that includes the above-mentioned battery.

[0006] The anode sheet according to a first aspect of the present invention includes: a current collector, an active material layer, a lithium replenishment layer, and a protective layer.

[0007] The anode sheet has a set thickness, and along the thickness direction of the anode sheet, the current collector has a first surface and a second surface facing away from each other; the active material layer is located on the first surface and the second surface, and at least one of the active material layer on the first surface and the active material layer on the second surface has a receiving groove recessed towards the current collector; the inner wall surface of the receiving groove is covered with the lithium replenishment layer; the outer surface of the lithium replenishment layer is covered with the protective layer for confining the lithium powder in the lithium replenishment layer within the receiving groove.

[0008] The anode sheet according to the embodiments of the present invention has at least the following beneficial effects:

[0009] In this embodiment, a protective layer is also provided on the outer surface of the lithium replenishment layer. The protective layer is used to confine the lithium replenishment layer within the receiving tank, thereby reducing the free lithium powder in the lithium replenishment layer and reducing dust and debris. Therefore, when the anode sheet of this embodiment is used in a battery, the K value of the battery can be reduced, thereby improving the battery's performance.

[0010] According to some embodiments of the present invention, the active material layer on the first surface and the active material layer on the second surface both have a receiving groove recessed towards the current collector, each receiving groove is provided with the lithium replenishment layer, and the surface of each lithium replenishment layer is covered with the protective layer.

[0011] According to some embodiments of the present invention, the anode plate has a set width, and the receiving groove is an elongated groove extending along the width direction of the anode plate.

[0012] According to some embodiments of the present invention, the anode plate has a set length, and the spacing between adjacent receiving grooves along the length direction of the anode plate is 1 mm to 2 mm.

[0013] According to some embodiments of the present invention, along the thickness direction of the anode sheet, the size of the active material layer is L1, the size of the receiving groove is L2, and 40% ≤ L2 / L1 ≤ 50%.

[0014] According to some embodiments of the present invention, along the thickness direction of the anode sheet, the size of the lithium replenishment layer is L3, the size of the protective layer is L4, and L3+L4≤L2.

[0015] According to some embodiments of this utility model, 70% ≤ L3 / L2 ≤ 80%.

[0016] According to some embodiments of the present invention, the receiving groove is a deep and narrow groove.

[0017] The battery according to a second aspect embodiment of the present invention includes the anode sheet described in the first aspect embodiment.

[0018] The battery according to the embodiments of the present invention has at least the following beneficial effects:

[0019] In the anode sheet of the first aspect embodiment, a protective layer is further provided on the outer surface of the lithium replenishment layer. The protective layer is used to confine the lithium replenishment layer within the receiving tank, thereby reducing the free lithium powder in the lithium replenishment layer and reducing dust and debris. Therefore, when the anode sheet of this embodiment is used in a battery, the K value of the battery can be reduced, thereby improving the performance of the battery.

[0020] The electrical device according to a third aspect embodiment of the present invention includes the battery described in the second aspect embodiment.

[0021] The electrical equipment according to the embodiments of this utility model has at least the following beneficial effects:

[0022] In the battery of the second aspect embodiment, a protective layer is further provided on the outer surface of the lithium replenishment layer. The protective layer is used to confine the lithium replenishment layer within the receiving tank, thereby reducing the free lithium powder in the lithium replenishment layer and reducing dust and debris. Therefore, when the anode sheet of this embodiment is used in the battery, the K value of the battery can be reduced, thereby improving the battery's performance and improving the performance of the electrical device.

[0023] 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

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0025] Figure 1 This is a schematic diagram of the structure of the anode sheet according to the first aspect of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of another anode sheet according to the first aspect of the present invention;

[0027] Figure 3 for Figure 1 A schematic diagram of the structure of the active substance layer.

[0028] Figure label:

[0029] Current collector 100, first surface 110, second surface 120;

[0030] Active material layer 200, receiving tank 210;

[0031] Lithium replenishment layer 300, protective layer 400. Detailed Implementation

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] Increasing the thickness of the anode sheet can increase the loading of active materials and reduce the proportion of inactive components, thereby improving the battery's energy density. However, increasing the anode sheet thickness lengthens the lithium-ion transport path, increasing battery impedance and leading to poor rate performance and electrode reaction kinetics. To address this, some technologies incorporate containment grooves within the anode active material layer to shorten the lithium-ion transport path. Simultaneously, to maintain battery energy density, a lithium replenishment layer is placed within the containment groove. However, directly placing a lithium replenishment layer within the containment groove can easily lead to lithium-ion ionization, increasing the battery's K-value.

[0037] The K-value refers to the voltage drop of the battery per unit time, usually expressed in mV / d, and is an indicator used to measure the self-discharge rate of lithium batteries. Specifically, K = (OCV1 - OCV2) / T2, where OCV1 is the open-circuit voltage after a time interval T1 after the cell has completed charging and discharging, and OCV2 is the open-circuit voltage after another time interval T2 after the cell has completed charging and discharging. A lower K-value means that the battery voltage drops less during storage, i.e., a lower self-discharge rate. Therefore, a lower K-value helps maintain the battery's charge and extend its lifespan. In addition, batteries with a smaller K-value exhibit less voltage change during storage and use, demonstrating higher voltage stability.

[0038] To address the aforementioned problems, the first aspect of this invention provides an anode sheet that can be used in a battery to reduce the battery's K-value, thereby improving battery performance. (See also...) Figure 1 , Figure 1 This is a schematic diagram of the structure of the anode sheet according to the first aspect of the present invention. The anode sheet of this embodiment includes: a current collector 100, an active material layer 200, a lithium replenishment layer 300, and a protective layer 400.

[0039] The current collector 100 is made of materials such as copper foil or composite copper foil. The anode sheet has a predetermined thickness, and along the thickness direction of the anode sheet, the current collector 100 has a first surface 110 and a second surface 120 facing each other. The active material layer 200 is, for example, a lithium-ion compound such as LiCoO2, LiNiO2, or LiMnO. Both the first surface 110 and the second surface 120 are covered with the active material layer 200. At least one of the active material layers 200 located on the first surface 110 and the second surface 120 has a receiving groove 210 recessed towards the current collector 100, thereby shortening the lithium-ion transport path in the active material layer 200 and reducing the battery impedance. The inner wall of the receiving groove 210 is covered with a lithium replenishment layer 300 to replenish the lithium ions lost in the active material layer 200, thereby ensuring the energy density of the battery. The outer surface of the lithium replenishment layer 300 is covered with a protective layer 400, such as a ceramic layer, which is used to confine the lithium powder in the lithium replenishment layer 300 within the receiving tank 210. Therefore, when the anode sheet of this embodiment is used in a battery, the free lithium powder in the lithium replenishment layer 300 can be reduced, and dust and debris can be reduced, thereby reducing the K-value of the battery and improving its performance.

[0040] Specifically, by reducing the ionization of lithium ions in the anode plate, the risk of micro-short circuits caused by excessive lithium ion ionization within the battery can be reduced. Reducing micro-short circuits helps maintain a uniform charge distribution within the battery, thereby lowering the K value. Furthermore, side reactions between ionized lithium ions and the electrolyte are a significant cause of battery performance degradation and increased self-discharge. In this embodiment, by controlling the ionization of lithium ions in the anode plate, these side reactions can be reduced, thereby maintaining electrolyte stability and battery performance, further reducing the K value. Moreover, reducing the number of ionized lithium ions promotes a more uniform distribution of lithium ions within the anode plate, which helps reduce uneven charge distribution within the battery, thus lowering the K value.

[0041] Reference Figure 2 , Figure 2 This is a schematic diagram of another anode sheet according to the first aspect of the present invention. Based on the above embodiment, the active material layer 200 on the first surface 110 and the active material layer 200 on the second surface 120 both have receiving grooves 210 recessed toward the current collector 100. Thus, when the anode sheet of the embodiment is used in a battery, the internal resistance of the battery can be further reduced. At the same time, in order to ensure the energy density of the battery, a lithium replenishment layer 300 is provided in each receiving groove 210, and a protective layer 400 is covered on the surface of each lithium replenishment layer 300.

[0042] Reference Figure 3 , Figure 3 for Figure 1A schematic diagram of the active material layer is shown. In some embodiments, the anode sheet has a predetermined width, and the receiving groove 210 is an elongated groove extending along the width direction of the anode sheet. On the one hand, the elongated receiving groove 210 extending along the width direction of the anode sheet can increase the coverage area of ​​the receiving groove 210, thereby reducing the impedance of the battery. On the other hand, since the receiving groove 210 extends along the width direction of the anode sheet, it is perpendicular to the conveying direction during the coating and rolling process of the anode sheet. Therefore, a grooving device, such as a laser, can be set on one side of the width direction of the anode sheet and the receiving groove 210 can be processed by reciprocating along the width direction of the anode sheet, thereby improving the processing efficiency of the anode sheet.

[0043] Based on the above embodiments, the anode sheet has a set length, and the spacing between adjacent receiving grooves 210 along the length direction of the anode sheet is 1mm to 2mm. Specifically, it is known that the smaller the spacing between the receiving grooves 210, that is, the higher the density of the receiving grooves 210, the lower the impedance of the anode sheet when used in the battery. However, a higher density of the receiving grooves 210 also means that more active material is removed, which will reduce the energy density of the battery and also reduce the processing efficiency of the anode sheet. In addition, if the spacing between the receiving grooves 210 is too small, the active material between adjacent receiving grooves 210 will be thin, which will easily cause the active material to detach from the anode sheet, thereby reducing the battery life. Based on this, this embodiment sets the spacing between adjacent receiving grooves 210 within a suitable range, which reduces the battery impedance, ensures the battery life, ensures the processing efficiency of the anode sheet, and saves manufacturing costs.

[0044] Reference Figure 2In some embodiments, the size of the active material layer 200 along the thickness direction of the anode sheet is L1, and the size of the receiving groove 210 is L2, with 40% ≤ L2 / L1 ≤ 50%. Specifically, the size of the receiving groove 210 along the thickness direction of the anode sheet, i.e., the depth of the receiving groove 210, means that the deeper the receiving groove 210, the shorter the lithium-ion transport path, and thus the lower the battery impedance. However, the deeper the receiving groove 210, the closer its bottom wall is to the current collector 100. Therefore, during processing, the current collector 100 is closer to the laser, which not only easily leads to thermal deformation of the current collector 100 but also increases the risk of current collector 100 breakdown. Deformation of the current collector 100 reduces the bonding strength between the active material and the current collector 100, making it easy for the active material to separate from the current collector 100, thus reducing the battery's lifespan. Breakdown of the current collector 100 reduces the strength of the anode sheet, making it easy for the anode sheet to break, which also reduces the battery's lifespan. Based on this, in this embodiment, the depth of the receiving groove 210 is set within a suitable range, that is, the depth of the receiving groove 210 accounts for 40% to 50% of the thickness of the active material layer 200. Thus, while ensuring low battery impedance, it has a sufficient service life.

[0045] Reference Figure 2 In some embodiments, along the thickness direction of the anode sheet, the size of the lithium replenishment layer 300 is L3, and the size of the protective layer 400 is L4, where L3 + L4 ≤ L2. That is, the total thickness of the protective layer 400 and the lithium replenishment layer 300 is not greater than the depth of the receiving groove 210, for example, L3 + L4 = L2 / 2 or L3 + L4 = L2. This prevents the protective layer 400 from protruding beyond the receiving groove 210 and forming a protrusion on the surface of the anode sheet, thereby improving battery safety and lifespan. Specifically, if a protrusion forms on the surface of the anode sheet, when the anode sheet is used in the battery, the protrusion will cause uneven stress distribution inside the battery, increasing the risk of deformation or breakage during charging and discharging. Furthermore, the protrusion will also cause a gap to form between the anode sheet and the cathode sheet, reducing the battery's energy density. Based on this, in this embodiment, the total thickness of the protective layer 400 and the lithium replenishment layer 300 is not greater than the depth of the receiving groove 210. For example, in some embodiments, the depth L2 of the receiving groove 210 is 15μm to 25μm, the thickness L1 of the lithium replenishment layer 300 is 13μm to 20μm, and the thickness L2 of the ceramic layer is ≤2μm, thereby effectively improving this problem.

[0046] Reference Figure 2, in some embodiments, 70% ≤ L3 / L2 ≤ 80%, that is, the thickness of the lithium supplement layer 300 accounts for 70% to 80% of the depth of the receiving groove 210. Specifically, it can be seen from the above embodiments that the total thickness of the lithium supplement layer 300 and the protective layer 400 is not greater than the depth of the receiving groove 210. Therefore, within this defined range, the thickness of the lithium supplement layer 300 is inversely proportional to the thickness of the protective layer 400. In other words, the thicker the lithium supplement layer 300, the thinner the protective layer 400. The thicker the protective layer 400, the higher the energy density of the battery. However, the thinner the protective layer 400, the lower the limiting ability for the lithium supplement layer 300, resulting in an increased degree of lithium layer dissociation. Correspondingly, the K value of the battery will also increase. Therefore, in this embodiment, the thickness of the lithium supplement layer 300 is set within a suitable range to make the battery have a smaller K value on the premise of ensuring the energy density of the battery.

[0047] Referring to Figure 2 , in some embodiments, the receiving groove 210 is a deep and narrow groove. For example, in the above embodiments, the receiving groove 210 is a long strip-shaped groove extending along the width direction of the anode sheet. Along the length direction of the anode sheet, the size of the receiving groove 210 is L5, and L5 < L2. Therefore, on the premise of removing the same volume of active material, the receiving groove 210 in this embodiment is deeper, that is, L2 is larger, thereby reducing the impedance of the battery.

[0048] Specifically, it can be understood that the receiving groove 210 is formed by digging a groove in the active material layer 200. That is to say, the formation of the receiving groove 210 will inevitably remove some active material, reducing the energy density of the battery. And the receiving groove 210 in this embodiment is a deep and narrow groove. When the anode sheet of this embodiment is used in a battery, on the premise of losing the same energy density, the battery can have a smaller impedance.

[0049] For the battery of the second aspect embodiment, the battery is, for example, a soft-pack battery, a steel-shell battery or a cylindrical battery. The battery includes the anode sheet of the first aspect embodiment. Specifically, the battery includes a housing, an anode sheet, a cathode sheet and a separator. The anode sheet, the separator and the cathode sheet are stacked and wound to form an electrode core, and the electrode core is disposed in the housing. Since the electrode core includes the anode sheet of the first aspect embodiment, and a protective layer 400 is further disposed on the outer surface of the lithium supplement layer 300 of the anode sheet. The protective layer 400 is used to limit the lithium supplement layer 300 in the receiving groove 210, thereby reducing the dissociation of lithium powder in the lithium supplement layer 300 and reducing dust debris. Therefore, when the anode sheet of this embodiment is used in a battery, the K value of the battery can be reduced, thereby improving the service performance of the battery.

[0050] It should be noted that the battery of this embodiment has all the technical features of the electrode sheet of the first aspect embodiment. Therefore, this embodiment has all the beneficial effects brought by the first aspect embodiment, which will not be elaborated here.

[0051] The electrical device in the third aspect embodiment is, for example, an electronic device such as a watch, mobile phone, or tablet, or a new energy electric vehicle or a hybrid electric vehicle. The electrical device includes the battery of the second aspect embodiment. A protective layer 400 is provided on the outer surface of the lithium replenishment layer 300 of the anode sheet in the battery. The protective layer 400 is used to confine the lithium replenishment layer 300 within the receiving groove 210, thereby reducing the free lithium powder in the lithium replenishment layer 300 and reducing dust and debris. Therefore, when the anode sheet of this embodiment is used in the battery, the K-value of the battery can be reduced, thereby improving the battery's performance and thus improving the performance of the electrical device.

[0052] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Furthermore, in the description of the present invention, the reference to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

Claims

1. An anode plate, characterized in that, include: The current collector has an anode plate with a set thickness, and along the thickness direction of the anode plate, the current collector has a first surface and a second surface that are opposite to each other; An active material layer is located on the first surface and the second surface, and at least one of the active material layer on the first surface and the active material layer on the second surface has a receiving groove recessed toward the current collector; A lithium replenishment layer is provided, wherein the inner wall of the receiving tank is covered with the lithium replenishment layer. A protective layer is provided on the outer surface of the lithium replenishment layer to confine the lithium powder in the lithium replenishment layer within the receiving tank.

2. The anode plate according to claim 1, characterized in that, Both the active material layer on the first surface and the active material layer on the second surface have a receiving groove recessed towards the current collector, each receiving groove is provided with a lithium replenishment layer, and the surface of each lithium replenishment layer is covered with the protective layer.

3. The anode sheet according to claim 1, characterized in that, The anode plate has a set width, and the receiving groove is an elongated groove extending along the width direction of the anode plate.

4. The anode sheet according to claim 3, characterized in that, The anode plate has a set length, and the spacing between adjacent receiving grooves along the length direction of the anode plate is 1 mm to 2 mm.

5. The anode plate according to claim 1, characterized in that, Along the thickness direction of the anode sheet, the size of the active material layer is L1, and the size of the receiving tank is L2, with 40% ≤ L2 / L1 ≤ 50%.

6. The anode plate according to claim 5, characterized in that, Along the thickness direction of the anode sheet, the size of the lithium replenishment layer is L3, the size of the protective layer is L4, and L3+L4≤L2.

7. The anode sheet according to claim 6, characterized in that, 70% ≤ L3 / L2 ≤ 80%.

8. The anode plate according to claim 1, characterized in that, The receiving groove is a deep and narrow groove.

9. A battery, characterized in that, Includes the anode sheet according to any one of claims 1 to 8.

10. Electrical equipment, characterized in that, Includes the battery as described in claim 9.

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