Negative electrode structure and battery

Abstract

The utility model provides a kind of negative electrode structure and battery, it is related to battery technical field, the negative electrode structure includes solid electrolyte layer, current collector, guide layer and elastic buffer layer.Current collector is set to one side of solid electrolyte layer, and current collector is provided with a plurality of recessed grooves to one side towards solid electrolyte layer, guide layer is set between solid electrolyte layer and current collector, and the recess of guide layer is abutted recessed groove setting, to recessed groove and guide layer limit formation accommodating space, and elastic buffer layer is attached to the inner wall surface of recessed groove.The utility model reduces the connection position of current collector to appear the case of impedance rise, and elastic buffer layer is attached to the inner wall surface of recessed groove, absorbs certain volume deformation when lithium ion grows nucleation in recessed groove, achieves the purpose of relieving stress concentration, maintains the interface of current collector to adhere, and ensures critical working current density.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and more specifically, to a negative electrode structure and a battery. Background Technology

[0002] Secondary batteries (rechargeable batteries) refer to battery types that achieve charging and discharging through reversible chemical reactions. Solid-state batteries refer to secondary batteries that use solid electrolytes to completely replace liquid electrolytes. They are divided into all-solid-state batteries (no liquid) and semi-solid / quasi-solid-state batteries (containing a small amount of liquid electrolyte). During charging and discharging, lithium ions migrate between the positive and negative electrodes through the electrolyte, while electrons are conducted through the external circuit. When the solid electrolyte is coupled, uneven cracks, voids, peeling, etc. may exist on the surface of the negative electrode foil, leading to interface pressure loss, increased interface contact impedance, and other problems that affect the product quality of the battery. Utility Model Content

[0003] The purpose of this invention is to provide a negative electrode structure and battery that reduces the impedance rise at the connection point of the current collector, thereby alleviating stress concentration, maintaining the interface adhesion of the current collector, ensuring the critical operating current density, and thus improving the product quality of the battery.

[0004] A first aspect of this utility model provides a negative electrode structure, the negative electrode structure comprising: Solid electrolyte layer; A current collector is disposed on one side of the solid electrolyte layer, and the side of the current collector facing the solid electrolyte layer has a plurality of recessed grooves; A guide layer is disposed between the solid electrolyte layer and the current collector, and the guide layer is disposed abutting against the notch of the recessed groove, so that the recessed groove and the guide layer define an accommodating space. An elastic buffer layer is attached to the inner wall of the recessed groove.

[0005] In one possible embodiment of this utility model, the cross-sectional shape of the elastic buffer layer is a trapezoidal structure, a square structure, or a conical structure.

[0006] In one possible embodiment of this utility model, the cross-sectional shape of the elastic buffer layer is semi-circular or arc-shaped.

[0007] In one possible embodiment of this invention, the end of the elastic buffer layer abuts against the guide layer.

[0008] In one possible embodiment of the present invention, the elastic buffer layer has a porous structure, the porous structure including at least one of vertical through holes and interlinked curved hole structures.

[0009] In one possible embodiment of this utility model, the porosity of the elastic buffer layer is Q, which satisfies: 20%≤Q≤60%.

[0010] In one possible embodiment of this utility model, the number of the recessed grooves is multiple, and the multiple recessed grooves are arranged in an array structure.

[0011] In one possible embodiment of the present invention, there is a gap between adjacent recessed grooves.

[0012] In one possible embodiment of the present invention, a barrier layer is further included, which abuts between the solid electrolyte layer and the guide layer.

[0013] A second aspect of this invention provides a battery comprising the negative electrode structure described in any of the above embodiments.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows: This utility model provides a negative electrode structure and battery in which the solid electrolyte layer of the negative electrode structure is arranged opposite to the current collector. Several recessed grooves are provided on the side of the current collector corresponding to the solid electrolyte layer. Lithium ions are induced into the recessed grooves for growth through a guiding layer. The recessed grooves facilitate the uniform deposition and stripping of lithium ions during the use of the negative electrode structure. The recessed grooves act as a containment space to control and regulate lithium deposition, reducing the impedance rise at the connection position of the current collector. An elastic buffer layer is attached to the inner wall of the recessed grooves. When lithium ions grow and nucleate in the recessed grooves, it absorbs a certain volume deformation, thereby relieving stress concentration, maintaining the interface adhesion of the current collector, ensuring the critical operating current density, and thus improving the product quality of the battery. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the negative electrode structure provided in some embodiments of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the negative electrode structure provided in some embodiments of the present invention. Figure 2 ; Figure 3 This is a schematic diagram of the negative electrode structure provided in some embodiments of the present invention. Figure 3 .

[0017] Explanation of key component symbols; 100 - Negative electrode structure; 110 - Current collector; 120 - Solid electrolyte layer; 121 - Recessed groove; 130 - Guide layer; 140 - Elastic buffer layer; 150 - Barrier layer; X - First direction; Y - Second direction. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0020] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0021] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. 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. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0023] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" 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 of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0024] The following detailed description, in conjunction with the accompanying drawings, outlines some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0025] In related technologies, secondary batteries (rechargeable batteries) refer to battery types that achieve charging and discharging through reversible chemical reactions. Solid-state batteries refer to secondary batteries that use solid electrolytes to completely replace liquid electrolytes. They are divided into all-solid-state batteries (no liquid) and semi-solid / quasi-solid-state batteries (containing a small amount of liquid electrolyte). During charging and discharging, lithium ions migrate between the positive and negative electrodes through the electrolyte, while electrons are conducted through the external circuit. When the solid electrolyte is coupled, uneven cracks, voids, peeling, etc. may exist on the surface of the negative electrode foil, leading to interface pressure loss, increased interface contact impedance, and other problems that affect the product quality of the battery.

[0026] refer to Figure 1 As shown, an embodiment of this application provides a negative electrode structure 100, which includes a solid electrolyte layer 120, a current collector 110, a guiding layer 130, and an elastic buffer layer 140.

[0027] For example, the negative electrode structure 100 is a multilayer composite structure, in which a solid electrolyte layer 120, a current collector 110, a guiding layer 130 and an elastic buffer layer 140 are stacked along the first direction X. The negative electrode structure 100 can be a negative electrode metal foil, which is a negative electrode material carrier that directly participates in the electrochemical reaction in the battery.

[0028] The current collector 110 is made of at least one of copper, steel, and nickel. The current collector 110 can be a copper current collector 110, a steel current collector 110, or a nickel current collector 110, or a composite current collector 110 of at least two of these three types. The solid electrolyte layer 120 isolates the current collector from the electrolyte, inhibiting side reactions and lithium dendrite growth. The solid electrolyte layer 120 can be one or more layers, including a polymer layer and / or an inorganic layer. For example, when the solid electrolyte layer 120 is a single layer, it is a polymer layer. When the solid electrolyte layer 120 has two layers, it includes a polymer layer and an inorganic layer, with the polymer layer close to the current collector 110. When the solid electrolyte layer 120 has three layers, it includes an inorganic layer, a polymer layer, and an inorganic layer arranged sequentially.

[0029] Specifically, such as Figure 1 As shown, the current collector 110 is disposed on one side of the solid electrolyte layer 120. The side of the current collector 110 facing the solid electrolyte layer 120 has several recessed grooves 121. A guide layer 130 is disposed between the solid electrolyte layer 120 and the current collector 110, and the guide layer 130 abuts against the notch of the recessed groove 121, thus defining an accommodating space with the recessed groove 121 and the guide layer 130. An elastic buffer layer 140 is attached to the inner wall of the recessed groove 121. The solid electrolyte layer 120 of the negative electrode structure 100 is disposed opposite to the current collector 110. The side of the current collector 110 corresponding to the solid electrolyte layer 120 has several recessed grooves 121. A recessed groove 121 is formed, and lithium ions are induced into the recessed groove 121 for growth through the guide layer 130. The recessed groove 121 facilitates the uniform deposition and stripping of lithium ions during use of the negative electrode structure 100. The recessed groove 121 serves as a containment space to control and regulate lithium deposition, reducing the impedance rise at the connection position of the current collector 110. An elastic buffer layer 140 is attached to the inner wall of the recessed groove 121. When lithium ions grow and nucleate in the recessed groove 121, it absorbs a certain volume deformation, thereby relieving stress concentration, maintaining the interface adhesion of the current collector 110, and ensuring the critical operating current density.

[0030] The elastic buffer layer 140 can be a composite network structure formed by impregnating and filling a porous polyimide (PI) three-dimensional skeleton with alumina (Al2O3) or zirconium oxide (ZrO2) sol into the porous PI skeleton and then thermosetting. The material of the elastic buffer layer 140 can also be one or a combination of polyetheretherketone (PEEK) porous membrane, bicontinuous polyurethane (PU) foam, PVDF-HFP / ceramic.

[0031] refer to Figure 1 and Figure 2As shown, the negative electrode structure 100 has a first direction X and a second direction Y, wherein the first direction X and the second direction Y are arranged perpendicularly to each other. For example, the first direction X refers to the length direction of the negative electrode structure 100, and the second direction Y refers to the height direction of the negative electrode structure 100. It is understood that the above definitions are only for ease of understanding the relative positional relationships of the parts in the negative electrode structure 100 and should not be construed as limitations on this application.

[0032] In one embodiment, alternatively, referencing Figure 2 and Figure 3 As shown, the cross-sectional shape of the elastic buffer layer 140 is a trapezoidal, square, or conical structure. That is, the cross-sectional shape of the elastic buffer layer 140 can be one or a combination of trapezoidal, square, or conical structures. The aforementioned polygonal elastic buffer layer 140 is adapted to the shape and size of the recessed groove 121. The polygonal elastic buffer layer 140 conforming to the recessed groove 121 can guide the deposited lithium ions to concentrate at the bottom of the groove, avoid accumulation on the sidewalls, have a large retention space, and can also protect the corners of the polygonal shape, reducing the puncture effect on the current collector 110. For example, part of the cross-sectional shape of the elastic buffer layer 140 is a trapezoidal structure, and another part of the cross-sectional shape of the elastic buffer layer 140 is a conical structure. In other examples, part of the cross-sectional shape of the elastic buffer layer 140 is a trapezoidal structure, and another part of the cross-sectional shape of the elastic buffer layer 140 is a conical or square structure. All of these are within the protection scope of this application and are not specifically limited here.

[0033] Furthermore, such as Figure 1 As shown, the end of the elastic buffer layer 140 abuts against the guide layer 130. The guide layer 130 not only serves as a guiding structure for the lithium-ion transport path, but also as a supporting carrier for the elastic buffer layer 140. The two directly contact each other to form a physical support point. The end of the elastic buffer layer 140 can provide a certain support and mutual restraint for the guide layer 130, preventing the elastic buffer layer 140 from shifting or falling off due to volume expansion or mechanical stress. This is suitable for scenarios with high charge and discharge rates.

[0034] In one embodiment, alternatively, referencing Figures 1 to 3 As shown, there are multiple recessed grooves 121 arranged in an array. Correspondingly, each recessed groove 121 corresponds to an elastic buffer layer 140. The arrayed arrangement of multiple recessed grooves 121 facilitates the uniform deposition and nucleation of lithium ions, reduces the local nucleation barrier, enables simultaneous deposition and nucleation of multiple recessed grooves 121, reduces the number of preferred growth paths, and can also guide the distribution of electric field lines, avoid excessively high local electric field intensity, and form a more uniform electric field.

[0035] In summary, the solid electrolyte layer 120 of the negative electrode structure 100 is arranged opposite to the current collector 110. The current collector 110 has several recessed grooves 121 on one side corresponding to the solid electrolyte layer 120. Lithium ions are induced into the recessed grooves 121 for growth through the guide layer 130. The recessed grooves 121 facilitate the uniform deposition and stripping of lithium ions during use of the negative electrode structure 100. The recessed grooves 121 serve as a containment space to control and regulate lithium deposition, reducing the impedance rise at the connection position of the current collector 110. The elastic buffer layer 140 is attached to the inner wall of the recessed grooves 121. When lithium ions grow and nucleate in the recessed grooves 121, it absorbs a certain volume deformation, thereby relieving stress concentration, maintaining the interface adhesion of the current collector 110, ensuring the critical operating current density, and thus improving the product quality of the battery.

[0036] refer to Figure 1 As shown, embodiments of this application provide another negative electrode structure 100, which includes a solid electrolyte layer 120, a current collector 110, a guiding layer 130, and an elastic buffer layer 140.

[0037] Specifically, such as Figure 1 As shown, the current collector 110 is disposed on one side of the solid electrolyte layer 120. The side of the current collector 110 facing the solid electrolyte layer 120 has a plurality of recessed grooves 121. The guide layer 130 is disposed between the solid electrolyte layer 120 and the current collector 110, and the guide layer 130 is disposed abutting against the notch of the recessed groove 121. The recessed groove 121 and the guide layer 130 define a receiving space. The guide layer 130 induces lithium ions to grow in the recessed groove 121. The recessed groove 121 facilitates the uniform deposition and stripping of lithium ions during the use of the negative electrode structure 100. The recessed groove 121, as a receiving space, controls and regulates lithium deposition, reducing the impedance rise at the connection position of the current collector 110.

[0038] In this embodiment, the elastic buffer layer 140 is attached to the inner wall of the recessed groove 121. The solid electrolyte layer 120 of the negative electrode structure 100 is disposed opposite to the current collector 110. The current collector 110 has a plurality of recessed grooves 121 on one side corresponding to the solid electrolyte layer 120. The elastic buffer layer 140 is attached to the inner wall of the recessed groove 121. When lithium ions grow and nucleate in the recessed groove 121, it absorbs a certain volume deformation, thereby relieving stress concentration, maintaining the interface adhesion of the current collector 110, and ensuring the critical operating current density.

[0039] It is easy to understand that the recessed groove 121 allows lithium ions to preferentially enter the groove by spatial constraint and providing a space to accommodate them, maintaining the smoothness of the connection layer position and avoiding protrusions. The recessed groove 121 can homogenize the deposition of the current collector 110, so that the positive electrode ions are deposited and uniformly nucleated at the position of the recessed groove 121, reducing the uneven deposition and glass of positive electrode ions, avoiding dendrite growth, reducing the occurrence of interface peeling or dendrite puncture, uneven current distribution and increased impedance during battery charge and discharge cycles, and ensuring the cycle stability of the battery.

[0040] In one embodiment, alternatively, referencing Figure 1 As shown, the cross-sectional shape of the elastic buffer layer 140 is semi-circular or arc-shaped, that is, the cross-sectional shape of the elastic buffer layer 140 can be one or a combination of semi-circular and arc-shaped, to avoid excessive concentration of dendrite nucleation points, reduce the local current density of the confinement effect of the recessed groove 121, suppress dendrite growth, and reduce the risk of interface peeling. Compared with the polygonal shape of the elastic buffer layer 140, it reduces the puncture effect of the corners. The arc-shaped structure reduces stress concentration, buffers the deformation stress of the current collector 110, reduces the risk of puncture, and has high mechanical strength.

[0041] Furthermore, such as Figure 1 As shown, the end of the elastic buffer layer 140 abuts against the guide layer 130. The guide layer 130 not only serves as a guiding structure for the lithium-ion transport path, but also as a supporting carrier for the elastic buffer layer 140. The two directly contact each other to form a physical support point. The end of the elastic buffer layer 140 can provide a certain support and mutual restraint for the guide layer 130, preventing the elastic buffer layer 140 from shifting or falling off due to volume expansion or mechanical stress. This is suitable for scenarios with higher charge and discharge rates.

[0042] In one embodiment, the elastic buffer layer 140 may optionally have a porous structure, which includes at least one of vertical through holes and interlinked curved hole structures. The curved hole structures extend the overall length path of the holes through a detour, which can compress and rebound the elastic buffer layer 140 when lithium expands, alleviate interface pressure fluctuations, and prevent cold soldering failure or contact breakage.

[0043] Optionally, the porosity Q of the elastic buffer layer 140 satisfies: 20%≤Q≤60%, the porosity Q of the elastic buffer layer 140 is greater than or equal to 20%, and the porosity Q of the elastic buffer layer 140 is less than or equal to 60%, which on the one hand ensures the flexibility and buffering properties of the elastic buffer layer 140, and on the other hand adjusts the balance between the lightweight and mechanical strength of the elastic buffer layer 140. For example, the porosity Q of the elastic buffer layer 140 is greater than or equal to 20%. The presence of pores reduces the material stiffness to a certain extent, allowing the volume of the elastic buffer layer 140 to deform. In addition, the porosity Q of the elastic buffer layer 140 is less than or equal to 60% to avoid structural collapse and to balance the lightweight and mechanical strength of the elastic buffer layer 140. Of course, the porosity Q of the elastic buffer layer 140 can be any value between 20% and 60%. For example, the porosity Q of the elastic buffer layer 140 can be 20%, 25%, 30%, 45%, 50%, 53%, and 60%, which will not be elaborated here.

[0044] In one embodiment, alternatively, referencing Figures 1 to 3 As shown, there are multiple recessed grooves 121 arranged in an array. Correspondingly, each recessed groove 121 corresponds to an elastic buffer layer 140. The arrayed arrangement of multiple recessed grooves 121 facilitates the uniform deposition and nucleation of lithium ions, reduces the local nucleation barrier, enables multiple recessed grooves 121 to deposit and nucleate simultaneously, reduces the number of preferred growth paths, and can also guide the distribution of electric field lines, avoid excessively high local electric field intensity, and form a more uniform electric field.

[0045] Optionally, combined Figure 2 and Figure 3 As shown, there is a gap between adjacent recessed grooves 121. On the one hand, this reduces the occurrence of lithium ion deposition that spans multiple recessed grooves 121. On the other hand, it allows the current collector 110 to directly connect and contact the conductive layer, which facilitates ion exchange between the current collector 110 and the conductive layer, reduces the occurrence of short circuits, and ensures the continuity of the electron conduction path.

[0046] The coverage rate of the recessed groove 121 is the ratio of the total vertical projection area of ​​the multiple recessed grooves 121 on the collector 110 to the surface area of ​​the collector 110. The coverage rate of the recessed groove 121 is 30% to 70%, and can be any value between 30% and 70%. For example, the coverage rate of the recessed groove 121 can be 30%, 35%, 40%, 45%, 50%, 53%, 60%, and 70%, which will not be elaborated here.

[0047] For example, the recess depth h of the recessed groove 121 is 10 μm to 50 μm, the opening length d of the recessed groove 121 is 30 μm to 150 μm, and the gap between adjacent recessed grooves 121 is 50 μm to 200 μm.

[0048] In one embodiment, alternatively, such as Figure 1 As shown, the negative electrode structure 100 also includes a barrier layer 150, which abuts between the solid electrolyte layer 120 and the guiding layer 130, and plays a role in isolating and blocking the solid electrolyte layer 120 and the guiding layer 130, so as to regulate the local ion flux and improve electron blocking, and suppress electron movement.

[0049] For example, the material of the barrier layer 150 can be LiF or Li3N. LiF and Li3N prevent electron tunneling and electrolyte decomposition through their high ionic conductivity and electronic insulation properties, thereby stabilizing the lithium metal anode interface. Their high mechanical strength can suppress lithium dendrites from piercing the solid electrolyte interface.

[0050] The present invention also provides a battery, which includes a positive electrode structure and a negative electrode structure 100 as described in any of the above embodiments. The number of positive electrode structures and negative electrode structures 100 can be one or more. The battery containing the negative electrode structure 100 has all the beneficial effects of the negative electrode structure 100, which will not be described in detail here.

[0051] The battery can be a lithium-ion battery, or it can be an alkali metal-ion battery such as a sodium-ion battery, potassium-ion battery, zinc-ion battery, magnesium-ion battery, calcium-ion battery, or liquid metal battery.

[0052] In one embodiment, the battery is assembled by methods such as stacking and winding. The battery shape includes pouch, prismatic, and cylindrical.

[0053] In all examples shown and described herein, any specific values ​​should be interpreted as merely exemplary and not as limitations; therefore, other examples of exemplary embodiments may have different values.

[0054] The embodiments described above are merely examples of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the protection scope of this utility model.

Claims

1. A negative electrode structure, characterized in that, include: Solid electrolyte layer; A current collector is disposed on one side of the solid electrolyte layer, and the side of the current collector facing the solid electrolyte layer has a plurality of recessed grooves; A guide layer is disposed between the solid electrolyte layer and the current collector, and the guide layer is disposed abutting against the notch of the recessed groove, so that the recessed groove and the guide layer define an accommodating space. An elastic buffer layer is attached to the inner wall of the recessed groove.

2. The negative electrode structure according to claim 1, characterized in that, The cross-sectional shape of the elastic buffer layer is trapezoidal, square, or conical.

3. The negative electrode structure according to claim 1, characterized in that, The cross-sectional shape of the elastic buffer layer is semi-circular or arc-shaped.

4. The negative electrode structure according to claim 1, characterized in that, The end of the elastic buffer layer abuts against the guide layer.

5. The negative electrode structure according to claim 1, characterized in that, The elastic buffer layer has a porous structure, which includes at least one of vertical through-holes and inter-linked curved pore structures.

6. The negative electrode structure according to claim 5, characterized in that, The porosity of the elastic buffer layer is Q, which satisfies: 20%≤Q≤60%.

7. The negative electrode structure according to any one of claims 1 to 6, characterized in that, The number of the recessed grooves is multiple, and the multiple recessed grooves are arranged in an array structure.

8. The negative electrode structure according to claim 7, characterized in that, There is a gap between adjacent recessed grooves.

9. The negative electrode structure according to any one of claims 1 to 6, characterized in that, It also includes a barrier layer that abuts between the solid electrolyte layer and the guide layer.

10. A battery, characterized in that, Includes the negative electrode structure as described in any one of claims 1 to 9.

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