All-solid-state thin film lithium ion battery and preparation method thereof

Abstract

The invention provides an all-solid-state thin film lithium ion battery and a preparation method thereof, a high-insulativity and low-roughness material is used as an insulating substrate layer, and a positive electrode current collector layer, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, a negative electrode current collector layer and an insulating packaging layer are sequentially deposited on the deposited insulating substrate layer from bottom to top through a patterning method. The electrochemical impedance of the battery is reduced as much as possible in structural design, and the performance of the battery can be fully exerted; secondly, the battery is packaged by adopting a graphical scheme, so that a relatively good packaging effect can be ensured, and the battery can stably run for a long time; meanwhile, an appropriate electrode leading-out scheme is adopted, the positive electrode current collector and the negative electrode current collector extend to the substrate, various electrode leading-out methods such as high-temperature welding or leading-out through a conductive adhesive tape are compatible, the risk of battery damage is avoided, and the packaging effect is not affected.

Description

Technical Field

[0001] The present invention belongs to the technical field of all-solid-state thin-film lithium-ion batteries, and particularly relates to an all-solid-state thin-film lithium-ion battery and a preparation method thereof. Background Art

[0002] All-solid-state thin-film lithium-ion batteries are a branch in the field of lithium-ion batteries and are currently the small electrochemical energy storage technologies with the most application potential. With the rapid growth of the Internet of Things (IoT) industry scale in China, a series of low-power micro and small electronic devices, such as radio frequency identification tags, micro sensors, smart cards, wearable electronic devices, and microelectromechanical systems, have been widely used in many fields. All-solid-state thin-film lithium-ion batteries have the characteristics of long service life and high reliability, are suitable for the above-mentioned low-power electronic devices, and help to promote the development of IoT devices towards integration, miniaturization, and intelligence.

[0003] All-solid-state thin-film lithium-ion batteries are usually manufactured by thin-film processes, such as magnetron sputtering, electron beam evaporation, vacuum thermal evaporation, chemical vapor deposition, atomic layer deposition, etc. Appropriate thin-film processes are selected according to actual needs to sequentially deposit a positive electrode current collector, a positive electrode, a solid electrolyte, a negative electrode, a negative electrode thin film, etc. on a substrate, thereby manufacturing a battery. LiPON (lithium phosphate nitride) is a commonly used solid electrolyte in all-solid-state thin-film lithium-ion batteries, and this material is relatively sensitive to water and oxygen in the air. In addition, the positive and negative electrode materials are not suitable for long-term exposure to air. Most of the existing technologies at present do not consider the need to prevent the erosion and damage of water and oxygen in the air for all-solid-state thin-film lithium-ion batteries.

[0004] For example, Chinese invention patent CN 115275363 A discloses an all-solid-state thin-film lithium-ion battery and a preparation method thereof. First, a composite positive electrode thin film is prepared on a positive electrode current collector by using a three-target intermittent co-deposition method combined with a high-temperature in-situ annealing technique; then, a solid electrolyte thin film is prepared on the composite positive electrode thin film by using a reactive sputtering deposition method combined with a low-temperature in-situ annealing technique; then, a composite negative electrode thin film is prepared on the solid electrolyte thin film by using a two-target continuous co-deposition method; finally, a negative electrode current collector thin film is prepared on the composite negative electrode thin film by using a single-target deposition method, and the all-solid-state thin-film lithium-ion battery is obtained after encapsulation. However, the battery provided in this document cannot ensure the effect of long-term isolation from air water and oxygen. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a general and effective all-solid-state thin-film lithium-ion battery and a preparation method thereof.

[0006] The present invention is implemented as follows:

[0007] In a first aspect, a all-solid-state thin-film lithium-ion battery has a structure that, from bottom to top, is successively: an insulating base layer, a positive current collector layer, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, a negative current collector layer, and an insulating encapsulation layer;

[0008] The area of the positive current collector layer is smaller than the area of the insulating base layer;

[0009] The area of the positive electrode layer is within the area range of the positive current collector layer;

[0010] The area of the solid electrolyte layer covers the positive electrode layer and part of the positive current collector layer;

[0011] The negative electrode layer has the same area as the positive electrode layer and is symmetrically distributed;

[0012] The negative current collector layer completely covers the negative electrode layer but does not contact the positive current collector layer, and the negative current collector layer extends to the insulating base layer;

[0013] The area of the insulating encapsulation layer covers the solid electrolyte layer, the positive electrode layer, and the negative electrode layer, and exposes part of the positive current collector layer and the negative current collector layer.

[0014] In a second aspect, a method for manufacturing the all-solid-state thin-film lithium-ion battery as described above includes the following steps:

[0015] Step 1: Use a material with high insulation and low roughness as the insulating base layer, such as ceramic alumina sheets, quartz, glass, etc.;

[0016] Step 2: Deposit a positive current collector thin film on the insulating base layer by a patterning method to obtain the positive current collector layer; among them, the material of the positive current collector thin film can be metal aluminum, metal titanium, metal nickel, etc., and the film thickness is several hundred nanometers, as long as the conductivity is good enough;

[0017] Step 3: Deposit a positive electrode thin film on the positive current collector layer. The positive electrode thin film needs to be within the area range of the positive current collector layer, and direct contact between the two can ensure that the resistance is small enough to obtain the positive electrode layer; among them, the material of the positive electrode thin film includes but is not limited to lithium cobaltate, lithium manganate, lithium nickelate, nickel cobalt manganese, etc., and the thickness is determined according to the actual capacity requirements, usually several hundred nanometers to several micrometers;

[0018] Step 4: Deposit a solid electrolyte thin film on the positive electrode layer. The deposition area should be able to cover the positive electrode layer and part of the positive current collector layer, so as to avoid contact between the positive part and the negative part and prevent internal short circuit of the battery to obtain the solid electrolyte layer; among them, the composition of the solid electrolyte thin film includes but is not limited to LiPON, doped LiPON (such as silicon-doped LiPON);

[0019] Step Five: Deposit a negative electrode thin film on the solid electrolyte layer. The area of the negative electrode thin film is the same as that of the positive electrode thin film in Step Three, and the two are symmetrically distributed to ensure a short lithium-ion transmission path and low electrochemical impedance. In addition, the thickness of the negative electrode thin film is determined according to the actual capacity requirement, and the negative electrode capacity should match the positive electrode capacity to fully exert the battery performance, obtaining a negative electrode layer;

[0020] Step Six: Deposit a negative electrode current collector thin film on the negative electrode layer. The negative electrode current collector thin film needs to completely cover the negative electrode layer but not contact the positive electrode current collector layer, obtaining a negative electrode current collector layer; wherein, the negative electrode current collector thin film is in direct contact with the negative electrode layer to ensure that the resistance is small enough, and the negative electrode current collector thin film needs to extend to the insulating substrate layer to reserve space for electrode lead-out;

[0021] Step Seven: Deposit a highly dense and highly insulating thin film material (such as silicon nitride material, etc.) as an insulating encapsulation layer on the negative electrode current collector layer. The area of the insulating encapsulation layer needs to cover the core part of the battery, that is, the solid electrolyte layer, the positive electrode layer and the negative electrode layer. In addition, part of the positive electrode current collector layer and the negative electrode current collector layer need to be exposed to reserve space for electrode lead-out.

[0022] The present invention has the following advantages:

[0023] 1. Provide a general and effective structural design scheme for all-solid-state thin-film lithium-ion batteries, and minimize the electrochemical impedance of the battery in the structural design, which helps to fully exert the battery performance.

[0024] 2. Adopt a patterning scheme to encapsulate the battery, which can ensure a good encapsulation effect and enable the battery to operate stably for a long time.

[0025] 3. Adopt a suitable electrode lead-out scheme, extend the positive and negative electrode current collectors to the substrate, and be compatible with various electrode lead-out methods, such as high-temperature welding or lead-out through a conductive tape, without the risk of damaging the battery and without affecting the encapsulation effect. Description of the Drawings

[0026] The following further describes the present invention with reference to the drawings in conjunction with the embodiments.

[0027] Figure 1 It is a cross-sectional view of the all-solid-state thin-film lithium-ion battery of the present invention.

[0028] 1. Insulating substrate layer; 2. Positive electrode current collector layer; 3. Positive electrode layer; 4. Solid electrolyte layer; 5. Negative electrode layer; 6. Negative electrode current collector layer; 7. Insulating encapsulation layer. Detailed Embodiments

[0029] Reference Figure 1As shown, this embodiment provides an all-solid-state thin-film lithium-ion battery and its manufacturing method. The specific idea is as follows:

[0030] An all-solid-state thin-film lithium-ion battery, whose structure from bottom to top is successively: an insulating base layer 1, a positive current collector layer 2, a positive electrode layer 3, a solid electrolyte layer 4, a negative electrode layer 5, a negative current collector layer 6, and an insulating encapsulation layer 7; wherein, the area of the positive current collector layer 2 is smaller than the area of the insulating base layer 1; the area of the positive electrode layer 3 is within the area range of the positive current collector layer 2; the area of the solid electrolyte layer 4 covers the positive electrode layer 3 and part of the positive current collector layer 2; the negative electrode layer 5 has the same area as the positive electrode layer 3 and is symmetrically distributed; the negative current collector layer 6 completely covers the negative electrode layer 5 but does not contact the positive current collector layer 2, and the negative current collector layer 6 extends to the insulating base layer 1; the area of the insulating encapsulation layer 7 covers the solid electrolyte layer 4, the positive electrode layer 3, and the negative electrode layer 5, and exposes part of the positive current collector layer 2 and the negative current collector layer 6.

[0031] The specific manufacturing steps are as follows:

[0032] Step 1: Use a material with high insulation and low roughness as the insulating base layer 1, such as ceramic alumina sheet, quartz, glass, etc.;

[0033] Step 2: Deposit a positive current collector thin film on the insulating base layer 1 by a patterning method. The material can be metal aluminum, metal titanium, metal nickel, etc. The thickness of the thin film is several hundred nanometers, and it is only necessary to ensure good conductivity to obtain the positive current collector layer 2;

[0034] Step 3: Deposit a positive electrode thin film on the positive current collector layer 2. The materials include but are not limited to lithium cobaltate, lithium manganate, lithium nickelate, nickel cobalt manganese, etc. The thickness is determined according to the actual capacity requirements, usually from several hundred nanometers to several micrometers. The positive electrode thin film needs to be within the area range of the positive current collector layer 2, and direct contact between the two can ensure that the resistance is small enough to obtain the positive electrode layer 3;

[0035] Step 4: Deposit a solid electrolyte thin film on the positive electrode layer 3. The deposition area should be able to cover the positive electrode layer 3 and part of the positive current collector layer 2, so as to avoid contact between the positive electrode part and the negative electrode part and prevent internal short circuit of the battery. The composition of the solid electrolyte thin film includes but is not limited to LiPON, doped LiPON (such as silicon-doped LiPON) to obtain the solid electrolyte layer 4;

[0036] Step 5: Deposit a negative electrode thin film on the solid electrolyte layer 4. The area of the negative electrode thin film is the same as the area of the positive electrode thin film in Step 3, and the two are symmetrically distributed to ensure a short lithium-ion transmission path and low electrochemical impedance. In addition, the thickness of the negative electrode thin film is determined according to the actual capacity requirements, and the negative electrode capacity should match the positive electrode capacity to fully exert the battery performance to obtain the negative electrode layer 5;

[0037] Step Six: Deposit a negative current collector film on the negative electrode layer 5. The negative current collector film should completely cover the negative electrode layer 5 but not contact the positive current collector layer 2, so that the negative current collector film and the negative electrode layer 5 are in direct contact to ensure that the resistance is small enough. Moreover, the negative current collector film should extend to the insulating substrate layer 1 to reserve space for electrode lead-out, thus obtaining the negative current collector layer 6;

[0038] Step Seven: Deposit a highly dense and highly insulating thin film material (such as silicon nitride material, etc.) on the negative current collector layer 6 as the insulating encapsulation layer 7. The area of the insulating encapsulation layer 7 should cover the core part of the battery, namely the solid electrolyte layer 4, the positive electrode layer 3 and the negative electrode layer 5. In addition, part of the positive current collector layer 2 and the negative current collector layer 6 should be exposed to reserve space for electrode lead-out.

[0039] The all-solid-state thin-film lithium-ion battery and its preparation method provided by the present invention have the following beneficial effects: On the one hand, in terms of structural design, the electrochemical impedance of the battery is reduced as much as possible, which helps to give full play to the battery performance. On the other hand, a patterning scheme is adopted for battery encapsulation, which can ensure a good encapsulation effect and enable the battery to operate stably for a long time. In addition, a suitable electrode lead-out scheme is adopted, extending the positive and negative current collectors to the substrate, which is compatible with various electrode lead-out methods, such as high-temperature welding or lead-out through a conductive tape, without the risk of damaging the battery and without affecting the encapsulation effect.

[0040] Although the specific embodiments of the present invention have been described above, those skilled in the art of this technology should understand that the specific embodiments we described are illustrative rather than used to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be covered by the scope protected by the claims of the present invention.

Claims

1. An all-solid-state thin-film lithium-ion battery, characterized in that: Its structure from bottom to top is: insulating base layer, positive electrode current collector layer, positive electrode layer, solid electrolyte layer, negative electrode layer, negative electrode current collector layer and insulating packaging layer; The area of ​​the positive electrode current collector layer is smaller than the area of ​​the insulating base layer; The area of ​​the positive electrode layer is within the area range of the positive electrode current collector layer; The area of ​​the solid electrolyte layer covers the positive electrode layer and part of the positive electrode current collector layer; The negative electrode layer has the same area as the positive electrode layer and is symmetrically distributed; The negative electrode current collector layer completely covers the negative electrode layer but does not contact the positive electrode current collector layer, and the negative electrode current collector layer extends to the insulating base layer; The insulating packaging layer covers the solid electrolyte layer, the positive electrode layer and the negative electrode layer, and exposes a portion of the positive electrode current collector layer and the negative electrode current collector layer.

2. The method for preparing an all-solid-state thin-film lithium-ion battery according to claim 1, characterized in that: The following steps are involved: Step 1: Use a material with high insulation and low roughness as the insulating base layer; Step 2: depositing a positive electrode current collector thin film on the insulating base layer by a graphic method to obtain a positive electrode current collector layer; Step 3: depositing a positive electrode thin film on the positive electrode current collector layer, wherein the positive electrode thin film needs to be located within the area of ​​the positive electrode current collector layer, to obtain a positive electrode layer; Step 4: depositing a solid electrolyte film on the positive electrode layer, the deposition area should be able to cover the positive electrode layer and part of the positive electrode current collector layer, to obtain a solid electrolyte layer; Step 5: depositing a negative electrode film on the solid electrolyte layer, wherein the area of ​​the negative electrode film is the same as that of the positive electrode film in step 3, and the two are symmetrically distributed to obtain a negative electrode layer; Step 6: depositing a negative electrode current collector film on the negative electrode layer, wherein the negative electrode current collector film needs to completely cover the negative electrode layer but cannot contact the positive electrode current collector layer, and the negative electrode current collector film needs to extend to the insulating base layer to obtain a negative electrode current collector layer; Step seven: deposit a high-density, high-insulation thin film material on the negative electrode current collector layer as an insulating packaging layer. The area of ​​the insulating packaging layer needs to cover the core part of the battery, namely the solid electrolyte layer, the positive electrode layer and the negative electrode layer. In addition, part of the positive electrode current collector layer and the negative electrode current collector layer need to be exposed.

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