Battery cell structure of solid-state battery, solid-state battery, battery manufacturing equipment and battery manufacturing process

Abstract

The invention belongs to the technical field of solid-state batteries, and particularly relates to a battery cell structure of a solid-state battery, the solid-state battery, battery manufacturing equipment and a battery manufacturing process, and the battery cell structure comprises a positive plate, a solid-state electrolyte layer and a negative plate which are arranged in sequence; the solid electrolyte layer is of a waveform structure, micro-nano salient point arrays are arranged on the surfaces of the two sides of the solid electrolyte layer, and self-repairing dynamic interface layers are arranged on the surfaces of salient points; one side, facing the solid electrolyte layer, of the positive plate is provided with a first waveform surface, and the first waveform surface has a gradient pore structure; the negative plate is provided with a second wave-shaped surface, and the second wave-shaped surface is provided with a gradient pore structure; wherein the repairing dynamic interface layer can automatically repair microcracks generated by circulation, and mechanical anchoring of the salient point array is matched, so that the problem of impedance increase caused by interface cracks of a traditional solid-state battery is solved, and the cycle life is remarkably prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid-state batteries, and specifically relates to a solid-state battery cell structure, a solid-state battery, battery manufacturing equipment, and a battery manufacturing process. Background Art

[0002] Solid-state batteries, also known as all-solid-state lithium batteries, are energy storage devices that do not contain liquid in their structure and all materials exist in solid form, relative to liquid lithium batteries. Specifically, it consists of positive electrode materials + negative electrode materials and electrolytes, while liquid lithium batteries consist of positive electrode materials + negative electrode materials + electrolytes and separators. Solid-state batteries use non-flammable solid-state battery electrolytes to replace flammable organic liquid electrolytes, which greatly improves the safety of the battery system. At the same time, it can better adapt to high-energy positive and negative electrodes and reduce the weight of the system, achieving a simultaneous increase in energy density. Among various new battery systems, solid-state batteries are the next-generation technology closest to industrialization. This has become a consensus in the industry and scientific community.

[0003] The Chinese patent application number is 202311807870.5, which discloses a solid-state battery cell structure package. The invention comprises a positive electrode sheet, a solid electrolyte layer and a negative electrode sheet arranged in sequence, the two sides of the solid electrolyte layer are coupled with the positive electrode sheet and the negative electrode sheet respectively, and the solid electrolyte layer has a wavy structure; it can solve the problem that the traditional solid-state battery adopts a layered stacking structure, has low production efficiency, and the electrode thickness is relatively thick, which affects the transmission between ions; a solid-state battery is also disclosed, including a solid-state battery cell structure, at least two of the cell structures are stacked, and a positive electrode collector is arranged on the outside of the positive electrode sheet after the stacking is completed, and a negative electrode collector is arranged on the outside of the negative electrode sheet; it can solve the problem that the solid-state battery is heavy and has low energy density.

[0004] In existing solid-state batteries, the thermal expansion characteristics of electrode materials and solid electrolytes are significantly different. During the charge and discharge cycle and temperature changes, periodic thermal stress is easily generated at the interface, leading to the generation and expansion of microcracks, and ultimately causing interface delamination, seriously affecting the battery cycle life and stability. In traditional structures, the contact area between the current collector and the electrode layer is limited, the contact resistance is high, and the resistance accumulation effect is obvious when multiple layers are stacked, resulting in a decrease in battery power performance; at the same time, there is a lack of targeted thermal management design, and local heat accumulates during high-rate charge and discharge, resulting in material performance degradation and safety hazards. Summary of the Invention

[0005] In response to the above-mentioned deficiencies in the prior art, the present invention provides a solid-state battery cell structure, a solid-state battery, battery manufacturing equipment and a battery manufacturing process to solve the problems in the above-mentioned background technology.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a solid-state battery cell structure, comprising a positive electrode sheet, a solid electrolyte layer, and a negative electrode sheet arranged in sequence; the solid electrolyte layer has a corrugated structure, and both sides of the solid electrolyte layer are provided with a micro-nanoscale bump array, and the surface of the bumps is provided with a self-healing dynamic interface layer; The positive electrode sheet is provided with a first corrugated surface on the side facing the solid electrolyte layer that matches the corrugated structure of one side of the solid electrolyte layer, and the first corrugated surface has a gradient pore structure; the negative electrode sheet is provided with a second corrugated surface on the side facing the solid electrolyte layer that matches the corrugated structure of the other side of the solid electrolyte layer, and the second corrugated surface has a gradient pore structure; Both sides of the solid electrolyte layer are coupled to the first corrugated surface of the positive electrode sheet and the second corrugated surface of the negative electrode sheet through the micro-nano level bump array and the self-repairing dynamic interface layer.

[0007] Furthermore, the bumps of the micro-nano level bump array are conical or truncated cone shaped, with a bump height of 1-5 μm, a bottom diameter of 5-20 μm, and a spacing between adjacent bumps of 20-50 μm.

[0008] Furthermore, the self-repairing dynamic interface layer is a polymer layer containing reversible dynamic covalent bonds, and the thickness of the self-repairing dynamic interface layer is 50-200 nm.

[0009] Furthermore, the waveform structure of the solid electrolyte layer is one of a sine wave structure, a square wave structure or a triangle wave structure.

[0010] Furthermore, the pores in the gradient pore structure present a continuous and gradual distribution from the interface side close to the solid electrolyte layer to the current collector side away from the solid electrolyte layer, the number of pores gradually decreases as they move away from the solid electrolyte layer, and the overall density of the pores decreases in a step-like manner from the interface side to the current collector side.

[0011] Furthermore, the total thickness of the solid electrolyte layer is 10-100 μm, the thickness of the positive electrode sheet is 20-300 μm, and the thickness of the negative electrode sheet is 10-200 μm.

[0012] Furthermore, a first conductive transition layer is provided on a side of the positive electrode sheet away from the solid electrolyte layer. The first conductive transition layer is a composite layer of conductive carbon nanotubes and graphene, and has a thickness of 1-5 μm.

[0013] Furthermore, a second conductive transition layer is provided on a side of the negative electrode sheet away from the solid electrolyte layer. The second conductive transition layer is a composite layer of conductive carbon black and carbon fiber, and has a thickness of 1-5 μm.

[0014] In a second aspect, the present invention also provides a solid-state battery comprising at least two of the above-mentioned cell structures, which are stacked in sequence. After stacking, a positive electrode collector is arranged on the outside of the first conductive transition layer of the outermost positive electrode sheet, and a negative electrode collector is arranged on the outside of the second conductive transition layer of the outermost negative electrode sheet. The positive electrode collector is press-connected to the first conductive transition layer, and the negative electrode collector is press-connected to the second conductive transition layer.

[0015] In a third aspect, the present invention further provides a battery manufacturing device, comprising a mold opening and closing unit for opening or closing an injection mold, wherein the inner wall of the mold cavity of the injection mold is provided with a micro-nano pit array matching the micro-nano level convex array, and the mold cavity is used to form the core of the solid electrolyte layer of the above-mentioned battery core structure; an atomic layer deposition unit, configured to deposit a shell on the surface of the core of the solid electrolyte layer, the atomic layer deposition unit comprising a precursor supply device and a vacuum reaction chamber; A pressing unit, used for pressing the positive electrode sheet, the solid electrolyte layer and the negative electrode sheet together, wherein the pressing head surface of the pressing unit is provided with a corrugated structure matching the first corrugated surface and the second corrugated surface; A coating unit is used to coat a self-repairing dynamic interface layer material on the surface of the micro-nano level convex dot array, and the coating unit adopts an aerosol jet printing device.

[0016] In a fourth aspect, the present invention further provides a battery manufacturing process for forming the above-mentioned solid-state battery cell structure, comprising the following steps: S1: Preparation of solid electrolyte layer: Injecting molten electrolyte into the mold cavity of an injection mold, and demolding after cooling to obtain a solid electrolyte layer with a corrugated structure and a micro-nanoscale bump array; S2: Preparing a positive electrode sheet: preparing a positive electrode slurry, injecting the positive electrode slurry into a mold having a first corrugated surface, forming the first corrugated surface having a gradient pore structure through a gradient sintering process, baking and pressing, and demolding the sheet, and coating a first conductive transition layer on the side away from the first corrugated surface; S3: preparing the negative electrode sheet: preparing the negative electrode slurry, injecting the negative electrode slurry into a mold having a second corrugated surface, forming the second corrugated surface having a gradient pore structure through a gradient sintering process, baking and pressing, and demolding the sheet, and coating a second conductive transition layer on the side away from the second corrugated surface; S4: aligning the first corrugated surface of the positive electrode sheet, one side of the solid electrolyte layer, and the second corrugated surface of the negative electrode sheet in sequence, and pressing them together by a pressing unit to form a two-cell battery; S5: stacking at least two of the two-part batteries, pressing a positive electrode current collector on the first conductive transition layer of the outermost positive electrode sheet, and pressing a negative electrode current collector on the second conductive transition layer of the outermost negative electrode sheet to form a battery cell; S6: baking the battery cell at a temperature of 80-120° C. for 2-4 hours.

[0017] Furthermore, the gradient sintering process in step S2 and step S3 is: pre-sintering at 30-60° C. for 1-2 hours, then heating to 100-150° C. at a rate of 5-10° C. / min, and keeping warm for 2-3 hours.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. Through the four-fold collaborative design of "waveform adaptation + bump anchoring + self-repair protection + gradient buffering", the core issues of solid-state batteries, such as insufficient interface contact, poor stability, and stress damage, are specifically addressed. The dynamic interface layer can autonomously repair microcracks generated by cycling. Combined with the mechanical anchoring of the bump array, it solves the problem of increased impedance caused by interface cracks in traditional solid-state batteries and significantly extends the cycle life. 2. The wave structure + micro-nano bump array significantly increases the interface contact area, and the gradient pore structure optimizes the wettability of the electrolyte to the electrode, shortens the ion transmission path, reduces the interface impedance, and improves the battery charge and discharge efficiency; 3. The waveform adaptation design and gradient pore structure work together to buffer the expansion and contraction differences between the electrode and the electrolyte, reducing stress concentration during cycling, lowering the risk of interfacial delamination, and improving battery structural stability. 4. The gradient pore structure enhances contact and buffering through high porosity on the electrolyte side and ensures electrode strength through low porosity on the far side. The self-healing layer gives the interface the ability to "self-heal from damage" without sacrificing ion conduction, achieving coordinated optimization of multiple performance indicators. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the structure of the battery cell of the solid-state battery of the present invention; Figure 2 Schematic diagram of the solid electrolyte layer in the core structure of the solid-state battery of the present invention; Figure 3 for Figure 2 A partial enlarged view of point A in the middle; Figure 4 Schematic diagram of the positive electrode sheet in the cell structure of the solid-state battery of the present invention; Figure 5 Schematic diagram of the negative electrode sheet in the cell structure of the solid-state battery of the present invention; Figure 6 A schematic diagram of a battery manufacturing device according to the present invention; Figure 7 A flow chart of a battery manufacturing process according to the present invention; The reference numerals in the drawings of the specification include: 1. Solid electrolyte layer; 101. Bump; 102. Self-healing dynamic interface layer; 2. Positive electrode sheet; 201. First conductive transition layer; 202. Positive electrode current collector; 203. Pores; 3. Negative electrode sheet; 301. Second conductive transition layer; 302. Negative electrode current collector. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the present invention, the technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0021] Among them, the drawings are only used for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting this patent; in order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0022] Due to the significant differences in thermal expansion characteristics between electrode materials and solid electrolytes in existing solid-state batteries, periodic thermal stress is easily generated at the interface during charge and discharge cycles and temperature changes, leading to the generation and expansion of microcracks, and ultimately causing interface peeling, which seriously affects the battery cycle life and stability. In traditional structures, the contact area between the current collector and the electrode layer is limited, the contact resistance is high, and the resistance accumulation effect is obvious when multiple layers are stacked, resulting in a decrease in battery power performance; at the same time, there is a lack of targeted thermal management design, and local heat accumulates during high-rate charge and discharge, resulting in material performance degradation and safety hazards.

[0023] The present invention provides a cell structure of a solid-state battery, comprising a positive electrode sheet, a solid electrolyte layer and a negative electrode sheet arranged in sequence; the solid electrolyte layer has a corrugated structure, and both side surfaces of the solid electrolyte layer are provided with a micro-nanoscale convex array, and the surfaces of the convex points are provided with a self-repairing dynamic interface layer; the side of the positive electrode sheet facing the solid electrolyte layer is provided with a first corrugated surface that matches the corrugated structure of one side of the solid electrolyte layer, and the first corrugated surface has a gradient pore structure; the side of the negative electrode sheet facing the solid electrolyte layer is provided with a second corrugated surface that matches the corrugated structure of the other side of the solid electrolyte layer, and the second corrugated surface has a gradient pore structure; the two sides of the solid electrolyte layer are coupled to the first corrugated surface of the positive electrode sheet and the second corrugated surface of the negative electrode sheet respectively through the micro-nanoscale convex array and the self-repairing dynamic interface layer.

[0024] The corrugated structure significantly increases the contact area between the electrolyte and the electrode compared to a planar structure. Combined with the micro-nanoscale bump array embedded in the electrode's gradient pores, this creates a "physical anchoring" effect—the bumps penetrate deep into the pores, and the pores fill the gaps between the bumps. This significantly increases the actual interface contact area, shortens the ion transport path, and reduces interfacial impedance. The self-healing dynamic interface layer on the bump surface acts as an "active buffer layer." During battery charge and discharge cycles, when microcracks form between the electrode and electrolyte due to expansion and contraction, the material's inherent reversible chemical and physical reactions (such as dynamic covalent bond recombination) autonomously heal these cracks, maintaining interfacial integrity and preventing impedance increases caused by crack propagation. The gradient pore structure of the electrode's corrugated surface exhibits a gradual porosity gradient from the electrolyte side to the distal side. This provides ample space for the electrolyte bumps to embed (enhancing wettability on the high-porosity side) while also gradually increasing the electrode's structural strength by decreasing porosity (ensuring mechanical stability on the low-porosity side). Furthermore, the synergistic effect of the corrugated structure and gradient pore structure buffers thermal and mechanical stresses during cycling, reducing the risk of interfacial delamination. The gradient pore structure optimizes the wettability of the electrolyte to the electrode, shortens the ion transmission path, reduces the interfacial impedance, and improves the battery charging and discharging efficiency. The waveform adaptation design and the gradient pore structure work together to buffer the expansion and contraction differences between the electrode and the electrolyte, reduce stress concentration during the cycle, reduce the risk of interfacial delamination, and improve the stability of the battery structure. The gradient pore structure enhances contact and buffering through high porosity on the side close to the electrolyte and ensures electrode strength through low porosity on the side away from the electrolyte. The self-healing layer gives the interface the ability to "self-heal from damage" without sacrificing ion conduction, thereby achieving coordinated optimization of multiple performance indicators.

[0025] In some embodiments, the bumps of the micro-nano scale bump array are conical or truncated cone shaped, with a bump height of 1-5 μm, a bottom diameter of 5-20 μm, and a spacing between adjacent bumps of 20-50 μm.

[0026] During the charge and discharge cycles of solid-state batteries, the electrodes and electrolyte expand and contract due to differences in material properties. The bump structure can be directly embedded into the gradient pores of the electrode, forming a physical anchoring structure similar to a "mortise and tenon joint"—the bumps of the electrolyte layer penetrate deep into the pores of the electrode, while the electrode material fills the gaps between the bumps, creating a mechanically interlocking interface. This structure effectively resists peeling forces during cycling, reduces stress-induced interfacial microcracks, and significantly improves interfacial stability. The bump design increases the effective contact area between the electrolyte and electrode through "three-dimensional extension." Building on the corrugated structure, the bumps protrude toward the electrode, transforming the original planar or simple corrugated contact into a three-dimensional "corrugated + bump" contact. This increased contact area shortens the ion transport path and reduces interfacial impedance, which is crucial for solid-state batteries that rely on interfacial contact for ion conduction. The solid electrolyte layer is produced through injection molding. The micro-nano pit array on the inner wall of the mold cavity can directly replicate the bump structure (mold pits → electrolyte bumps). This process is mature and easily controlled in precision (the height and spacing of the micro-nano bumps can be precisely set using the mold). The bump structure is easier to form during the cooling and solidification process of the molten electrolyte, and the connection strength between the bump root and the electrolyte layer body is higher, and it is not easy to fall off during subsequent processing.

[0027] In addition, let me explain why bumps are designed instead of pits on the surface of the solid electrolyte layer. First, in the pit design, the contact between the electrolyte and the electrode mainly relies on the edge of the pit. Instead, a "cavity area" is formed inside the pit, which cannot participate in ion transmission, resulting in increased interface impedance. Second, the pit structure cannot form an effective mechanical anchor - if the electrode material is to match the pit, it needs to form a bump itself, but the electrode active material (such as ternary materials, graphite) is usually very brittle, and the micro-nano-level bumps are prone to breakage during pressing or cycling; even if the electrode remains flat, the edge of the pit will become a stress concentration area, which is prone to cracks during cycling, leading to interface peeling. The pit structure is prone to retaining bubbles or impurities during the pressing process, forming an ion transmission "dead zone"; at the same time, the electrolyte thickness at the bottom of the pit increases, which will extend the ion transmission path and reduce the conduction efficiency. Third, the pits need to be processed into a concave structure on the surface of the electrolyte layer. The pit formation at the micro-nano scale is prone to problems such as edge burrs and uneven depth. In addition, the material thickness at the bottom of the pit is relatively thin, and cracks are easily generated due to uneven stress during cooling and solidification, which reduces the structural integrity of the electrolyte layer and makes the manufacturing process more difficult.

[0028] In certain embodiments, the self-healing dynamic interface layer is a polymer layer containing reversible dynamic covalent bonds. The self-healing dynamic interface layer has a thickness of 50-200 nm and completely covers the entire surface of the micro-nano bumps and the surface of the solid electrolyte layer between adjacent bumps, forming a continuous and uninterrupted interface repair layer. The self-healing dynamic interface layer is a polymer layer containing reversible dynamic covalent bonds, which is used to achieve autonomous crack healing through reversible recombination of chemical bonds when microcracks form at the interface. The reversible dynamic covalent bonds include Diels-Alder bonds.

[0029] Specifically, the self-healing dynamic interface layer is a key functional structure in solid-state batteries. Its core function is to dynamically repair interface microcracks, relieve stress, and maintain ion transmission efficiency. The self-healing dynamic interface layer is usually composed of the following four types of materials: 1. Dynamic chemical bond polymer matrices, commonly including polyether polyurethane (PTMG-HDI-BHDS), dynamic imine bond elastomers, and disulfide cross-linked polymers. Dynamic bonds (such as disulfide and imine bonds) can achieve crack healing through reversible fracture-recombination when interfacial cracking occurs, while hydrogen bond networks provide rapid physical cross-linking to assist in repair.

[0030] 2. Ion-conducting media include composite systems containing lithium salts (such as LiFSI) and ionic liquids (such as triethylene glycol dimethyl ether), or liquid gallium-based alloys (primarily gallium-indium-tin, with additives such as bismuth and zinc). The liquid alloy solidifies during lithium insertion and liquefies during lithium removal, adaptively adapting to interface deformation through solid-liquid transformation. The ionic liquid combines with the lithium salt to form a dynamic environment with high ionic conductivity, ensuring smooth ion transmission during the repair process.

[0031] 3. Reinforcing fillers and interfacial modifiers include: Inorganic nanoparticles, such as amino-functionalized ZIFs and modified hexagonal boron nitride (h-BN), are used to enhance mechanical strength and thermal conductivity. Coupling agents, such as silane coupling agents (such as KH550) and isopropyl titanate, enhance the interfacial bonding between polymers and electrodes / electrolytes. ZIFs form hydrogen bonds with the polymer matrix through amino groups, providing ion transport pathways. h-BN binds to polymer chains through π-π stacking, creating a thermally conductive network.

[0032] 4. Auxiliary additives include corrosion inhibitors such as benzimidazole (BIM) and dichloromethylbenzimidazole (2CBI) to inhibit interfacial side reactions. Antioxidants such as vitamin E and hindered phenolic compounds prevent polymer oxidative degradation. During the repair process, the corrosion inhibitors are released to form a passivation film to protect the electrode surface; antioxidants extend the material's service life.

[0033] In certain embodiments, the waveform structure of the solid electrolyte layer is one of a sine wave structure, a square wave structure, or a triangle wave structure.

[0034] Specifically, the sinusoidal wave structure presents a continuous, smooth, periodic curve, and its contour conforms to the laws of the sine function: the peaks and troughs transition naturally through the curved surface, without obvious edges or turns. The smooth curved surface can evenly disperse the interfacial stress during the charge and discharge cycle, avoiding crack initiation caused by local stress concentration. It is particularly suitable for long-term cycling scenarios. The continuous and uninterrupted surface enables the contact area between the electrolyte and the electrode to form a complete closed loop, making the ion transmission path smoother and the interface impedance fluctuation smaller. The curved structure can adapt to the tiny undulations of the electrode surface through elastic deformation during the pressing process, reducing poor contact caused by processing errors. It is suitable for the field of power batteries with high requirements for cycle stability.

[0035] The square wave structure consists of alternating horizontal planes and vertical surfaces, exhibiting a "stepped" periodic morphology: the peaks and troughs are parallel planar segments, connected by vertical or near-vertical vertical surfaces. The horizontal planar segments create a large parallel contact area, and combined with the lateral contact of the vertical vertical surfaces, the stepped structure forms a "mortise and tenon" fit with the gradient porosity of the electrode. The vertical vertical surfaces embed into the deep pores of the electrode, enhancing the mechanical interfacial locking force. The uniform thickness of the planar segments reduces localized accumulation of electrolyte material, saving electrolyte usage compared to sine waves for the same contact area, making it suitable for applications with high power performance requirements (such as energy storage batteries).

[0036] The triangular wave structure exhibits a zigzag, periodic morphology, with crests formed by the intersection of two symmetrical, inclined straight lines. Adjacent crests are connected to troughs by inclined straight lines, creating an overall profile resembling a continuous triangular arrangement. The inclined hypotenuse guides the electrode material toward the troughs during the pressing process, reducing interfacial bubble retention. The straight hypotenuse forms a linear match with the electrode's gradient pore structure, resulting in a uniform change in contact pressure from crest to trough, accommodating the gradient porosity distribution. Compared to the complex curves of a sine wave, the straight contours of a triangular wave are easier to process in injection molds, making dimensional accuracy control simpler. This makes it suitable for large-scale mass production of consumer electronics batteries.

[0037] In certain embodiments, the pores in the gradient pore structure present a continuous gradient distribution from the interface side close to the solid electrolyte layer to the current collector side away from the solid electrolyte layer, the number of pores gradually decreases as the distance from the solid electrolyte layer increases, and the overall density of the pores decreases stepwise from the interface side to the current collector side. The pores are densely distributed in the interface region close to the solid electrolyte layer, providing embedding space for the micro-nano-scale bumps on the surface of the solid electrolyte layer. The gaps between the pores can accommodate the bump structure and fill the microscopic voids in the interface region, forming a complementary mosaic structure of pores and bumps. The size of the pores gradually decreases as the distance from the solid electrolyte layer increases. The pore size on the interface side is larger and more evenly distributed, providing sufficient space for the bump embedding. In the process of extending toward the current collector side, the pore size gradually decreases, and the spacing between the pores gradually increases, so that the density of the electrode structure is smoothly increased. The gradient distribution of the pores has no obvious stratification boundary. Through the continuous and gradual changes in density and size, a stress-free transition of the electrode material from the loose structure on the interface side to the dense structure on the current collector side is achieved, which can buffer the interfacial stress generated by the difference in expansion and contraction between the electrode and the electrolyte.

[0038] "Pore count" refers to the actual number of pores per unit volume. Starting from the interface side of the electrode near the solid electrolyte layer and moving away from the electrolyte layer and toward the current collector, the number of pores per cubic millimeter is greater in the high-porosity region on the interface side. "Pore density" refers to the ratio of the total pore volume to the electrode volume in the area (i.e., porosity). "Step-by-step reduction" emphasizes that this density change presents a phased gradient feature: the first stage (high-pore layer on the interface side): the area close to the solid electrolyte layer is a high-pore density area with the highest porosity (30-50%). At this time, the number of pores is large and the distribution is dense, and the overall structure is looser. The purpose is to provide sufficient embedding space for the electrolyte bumps, while reserving a buffer gap for expansion and contraction; the second stage (intermediate transition layer): the intermediate area transitioning towards the current collector The first domain is a medium pore density zone with a medium porosity (30-35%). The number of pores is reduced compared to the first stage, and the density is lower than that of the first stage, achieving a smooth transition from "loose" to "dense" and avoiding stress concentration due to sudden density changes; the third stage (low-pore layer on the current collector side): the area close to the current collector is a low pore density zone with the lowest porosity (10-20%), the least number of pores, the lowest density, and a denser overall structure. The purpose is to ensure the mechanical strength of the contact area between the electrode and the current collector, reduce the space occupied by active materials to increase energy density. The "step-by-step" here does not mean that there are obvious "steps" or "faults", but that the pore density of different regions is divided into a gradient of "high → medium → low" through process control, and there is no obvious interface between the regions, achieving a continuous transition of density.

[0039] As one moves deeper into the electrode, the number of pores within the same volume gradually decreases (the number of holes decreases significantly). In the low-porosity region near the current collector, the number of pores per unit volume reaches a minimum (only a small number of tiny pores exist). This reduction in pore number is essentially consistent with a step-by-step decrease in density: a decrease in pore number directly leads to a decrease in the proportion of pores per unit volume (density), while a step-by-step decrease clarifies the phased nature of this decrease. A high number and high density of pores on the interface side accommodate the micro-nano bumps of the electrolyte, increasing contact area and buffering stress. Gradually decreasing pore number and density toward the current collector side gradually improves the electrode's structural strength, avoiding insufficient mechanical properties due to overall porosity. This smooth, step-by-step transition eliminates interfacial stress caused by sudden density changes, ensuring that the electrode is less susceptible to cracking due to expansion and contraction during cycling, while also guiding the smooth transfer of ions from the electrolyte into the electrode.

[0040] In certain embodiments, the total thickness of the solid electrolyte layer is 10-100 μm, the thickness of the positive electrode sheet is 20-300 μm, and the thickness of the negative electrode sheet is 10-200 μm. The solid electrolyte layer has a core-shell structure, with the core being a sulfide electrolyte and the outer shell being a 5-10 nm Li3BO3 layer coated by atomic layer deposition technology. In one embodiment, the specific structure of the solid electrolyte layer, wherein the core body is Li7P3S 11 The sulfide electrolyte forms the basic framework of the corrugated structure, with a thickness of 25-70μm, accounting for 85-90% of the total thickness. The outer shell: A 5-10nm thick Li₃BO₃ thin film uniformly coats the core surface, completely covering all core surfaces, including the corrugated contours and bump structure, forming a dense protective layer. The micro-nano bump array: Frustum-shaped bumps are evenly distributed on the corrugated surface on both sides of the solid electrolyte layer, with a bump density of 50-100 bumps / mm². Each bump is 2-4μm high, with a base diameter of 8-15μm and a top diameter that is 1 / 2-2 / 3 of the base diameter. The spacing between adjacent bumps is 25-40μm, forming a regular matrix arrangement with distribution in both the peaks and troughs. The self-healing dynamic interface layer: Completely covering all bump surfaces and the corrugated areas on both sides of the electrolyte layer, with a thickness of 80-150nm, presents a continuous film. The material is a polyimide-epoxy copolymer containing Diels-Alder bonds, which is tightly attached to the surface of the Li3BO3 shell and maintains a uniform thickness on the top and sides of the bump.

[0041] In some embodiments, a first conductive transition layer is provided on a side of the positive electrode sheet away from the solid electrolyte layer. The first conductive transition layer is a composite layer of conductive carbon nanotubes and graphene and has a thickness of 1-5 μm.

[0042] The overall shape of the positive electrode sheet is a rectangular sheet structure with a thickness of 100-200μm. The side facing the solid electrolyte layer is a first waveform surface that matches the electrolyte waveform. The waveform contour is completely consistent with one side of the solid electrolyte layer. The other side is a planar structure with the surface covered with a first conductive transition layer. Three-layer gradient structure from the electrolyte side to the current collector side; the first layer (composite layer): thickness accounts for 1 / 5, thickness 20-40μm. 0.8 Co 0.1 Mn 0.1 O2 is compounded with 25-30vol% Li3BO3, presenting a porous structure with a porosity of 40-50%. The pores are irregularly distributed, and the pore density is higher near the electrolyte side. The thermal expansion coefficient is 12×10⁻ 6 / ℃, and the thermal expansion coefficient of the solid electrolyte layer (9×10⁻ 6 / ℃) is close.

[0043] The second layer (transition layer): thickness accounts for 1 / 5, thickness is 20-40μm. 0.8 Co 0.1 Mn 0.1 The O2 content is increased to 85-90 vol%, and the Li3BO3 content is reduced to 10-15 vol%. The porosity is 30-35%, and the pore size is slightly smaller than the first layer and the distribution is more uniform. The thermal expansion coefficient is reduced to 10×10⁻ 6 / ℃, achieving a smooth transition with the first layer. The third layer (pure active material layer): 3 / 5 of the thickness, 60-120μm. It is pure LiNi 0.8 Co 0.1 Mn 0.1 O2 active material, porosity 10-20%, pores decrease gradually, pores are slightly larger near the second layer. Thermal expansion coefficient is stable at 8×10⁻ 6 / ℃, matching the thermal expansion characteristics of the current collector.

[0044] The first conductive transition layer is tightly adhered to the flat side of the positive electrode away from the electrolyte. It is 3-5μm thick and presents a uniform thin film. It is composed of a three-dimensional conductive network interwoven with carbon nanotubes with a diameter of 5-10nm, graphene sheets with a thickness of 0.34nm, and nickel-coated carbon fibers with a diameter of 50-100nm. The carbon fibers are randomly distributed, and the carbon nanotubes and graphene sheets evenly fill the gaps.

[0045] In some embodiments, a second conductive transition layer is provided on a side of the negative electrode sheet away from the solid electrolyte layer. The second conductive transition layer is a composite layer of conductive carbon black and carbon fiber, and has a thickness of 1-5 μm.

[0046] Specifically, the negative electrode sheet is symmetrically distributed with the positive electrode sheet, with a rectangular sheet structure and a thickness of 80-150μm. The side facing the solid electrolyte layer has a second corrugated surface that completely matches the waveform on the other side of the electrolyte layer. The other side is a flat structure covered by a second conductive transition layer. Three-layer gradient structure from the electrolyte side to the current collector side: The first layer (composite layer): 1 / 4 of the thickness, 20-37.5μm. It is composed of graphite and 25-30vol% Li3BO3, with a porosity of 40-50% and a thermal expansion coefficient of 11×10⁻ 6 / ℃. The second layer (transition layer): 1 / 4 of the thickness, 20-37.5μm. Graphite content 85-90vol%, Li3BO3 content 10-15vol%, porosity 30-35%, thermal expansion coefficient 9×10⁻ 6 / ℃. The third layer (pure active material layer): 2 / 4 of the thickness, 40-75μm. Pure graphite material, porosity 10-20%, thermal expansion coefficient 7×10⁻ 6 / ℃. Second conductive transition layer: attached to the flat side of the negative electrode away from the electrolyte, with a thickness of 3-5μm. It is composed of conductive carbon black with a particle size of 20-30nm, carbon fiber and copper-coated carbon nanotubes, with a volume resistivity of ≤5×10⁻ 5 Ω・cm, forming a uniform conductive film In a second aspect, the present invention further provides a solid-state battery comprising at least two of the aforementioned cell structures, the cell structures being stacked in sequence. A positive current collector is disposed on the outer side of the first conductive transition layer of the outermost positive electrode sheet, and a negative current collector is disposed on the outer side of the second conductive transition layer of the outermost negative electrode sheet. The positive current collector is press-fitted to the first conductive transition layer, and the negative current collector is press-fitted to the second conductive transition layer. The positive current collector is aluminum foil or aluminum alloy foil with a thickness of 6-15 μm; the negative current collector is copper foil or copper alloy foil with a thickness of 6-15 μm. In a third aspect, the present invention further provides a battery manufacturing device, comprising a mold opening and closing unit for opening or closing an injection mold, wherein the inner wall of the mold cavity of the injection mold is provided with a micro-nano pit array matching the micro-nano level convex array, and the mold cavity is used to form the core of the solid electrolyte layer of the above-mentioned battery core structure; an atomic layer deposition unit, configured to deposit a shell on the surface of the core of the solid electrolyte layer, the atomic layer deposition unit comprising a precursor supply device and a vacuum reaction chamber; A pressing unit, used for pressing the positive electrode sheet, the solid electrolyte layer and the negative electrode sheet together, wherein the pressing head surface of the pressing unit is provided with a corrugated structure matching the first corrugated surface and the second corrugated surface; A coating unit is used to coat a self-repairing dynamic interface layer material on the surface of the micro-nano level convex dot array, and the coating unit adopts an aerosol jet printing device.

[0047] In a fourth aspect, the present invention further provides a battery manufacturing process for forming the above-mentioned solid-state battery cell structure, comprising the following steps: S1: Preparation of solid electrolyte layer: Injecting molten electrolyte into the mold cavity of an injection mold, demolding after cooling, and obtaining a solid electrolyte layer with a corrugated structure and a micro-nano-scale bump array. S11: Injecting the molten sulfide electrolyte into the mold cavity of the injection mold, and demoulding after cooling to obtain a solid electrolyte layer core with a corrugated structure and a micro-nano level bump array; specifically, the sulfide electrolyte (such as Li7P3S 11 ) is injected into a precisely machined, corrugated mold cavity. The inner wall of the mold cavity is pre-set with a micro-nano pit structure that matches the bump array. The cooling process is controlled by a temperature rate (5-10°C / min) to avoid internal stress, ensuring the accuracy of the waveform profile (peak / trough error ≤ 2μm) and the integrity of the bumps (height deviation ≤ 0.5μm). After demolding, the core surface roughness is controlled to Ra ≤ 10nm, providing a flat base for subsequent shell deposition. S12: The core of the solid electrolyte layer is placed in the vacuum reaction chamber of the atomic layer deposition unit, and Li(tmhd)3 and B2H6 are used as precursors to deposit a 5-10nm Li3BO3 shell. The specific vacuum reaction chamber pressure is maintained at 1-5Torr, and Li(tmhd)3 (lithium source) and B2H6 (boron source) are used as precursors. Atomic-level layer-by-layer growth is achieved through alternating pulses (Li source pulse 0.5s→purge2s→B source pulse 0.5s→purge2s). The deposition temperature is controlled at 150-200℃ to ensure that the precursor is fully decomposed and evenly covers all surfaces of the core (including the top, side and waveform slope of the bump), and finally forms a 5-10nm dense film to isolate the side reactions of sulfide and air / electrode. S13: A dynamic covalent polymer solution containing Diels-Alder bonds is sprayed onto the surface of the micro-nanoscale bump array using an aerosol jet printer. UV curing is performed to form a 50-200 nm thick self-healing dynamic interface layer. The dynamic covalent polymer solution (polyimide-epoxy copolymer containing Diels-Alder bonds, solid content 10-15%) is atomized through a 0.1 mm nozzle and sprayed at a pressure of 0.5 MPa under an inert atmosphere (Ar gas protection) to ensure full coverage of the bump surface and no droplet aggregation. UV curing utilizes a 365 nm wavelength, an energy density of 500-800 mJ / cm², and a curing time of 30-60 seconds, causing the polymer to crosslink and form a continuous film of 80-150 nm with a thickness deviation of ≤10 nm.

[0048] S2: Preparing a positive electrode sheet: preparing a positive electrode slurry, injecting the positive electrode slurry into a mold having a first corrugated surface, forming the first corrugated surface having a gradient pore structure through a gradient sintering process, baking and pressing, and demolding the sheet, and coating a first conductive transition layer on the side away from the first corrugated surface; A positive electrode slurry is prepared, and the positive electrode slurry is coated twice. The first coating is a composite slurry containing 10-30 vol% Li3BO3 with a thickness of 20-30 μm, and the second coating is a pure positive electrode active material slurry with a thickness of 100-150 μm. The positive electrode slurry is injected into a mold having a first corrugated surface, and a first corrugated surface with a gradient pore structure is formed through a gradient sintering process. After baking and pressing, the mold is demolded, and a first conductive transition layer is coated on the side away from the first corrugated surface.

[0049] The specific composite slurry (first layer) consists of LiNi 0.8 Co 0.1 Mn 0.1 O2, Li3BO3 (10-30 vol%), and a binder (PVDF) are mixed in a ratio of 85:10:5, using NMP as the solvent and a solid content of 50-60%. A 20-30 μm wet film is formed by doctor blade coating. The pure active material slurry (second and third layers) does not contain Li3BO3, and the solid content is increased to 60-70%. The total coating thickness is 100-150 μm, forming a composition gradient with the composite slurry layer. Pre-sintering stage (30-60°C, 1-2h): slowly evaporate the solvent (NMP residue ≤ 0.1%) to avoid surface cracking caused by rapid drying, and at the same time allow the slurry particles to initially accumulate to form a loose skeleton. Heating stage (5-10℃ / min to 100-150℃): The low heating rate reduces thermal stress and prevents interlayer delamination; as the temperature rises, Li3BO3 gradually melts and fills some gaps, regulating the pore distribution. Insulation stage (100-150℃, 2-3h): Promote the decomposition of the binder (remove organic residues) and the contact fusion between particles, so that the composite layer forms a porosity of 40-50% (suitable for the embedding of electrolyte bumps), and the pure active material layer forms a low porosity of 10-20% (to ensure structural strength), and the porosity between the two layers is continuously gradient (no obvious interface).

[0050] After baking and rolling, the roughness of the positive electrode plane is controlled at Ra≤50nm. The first conductive transition layer (carbon nanotubes + graphene + nickel-coated carbon fiber, solid content 5%) is coated by a scraper with a thickness of 3-5μm. The volume resistivity after pressing is ≤1×10⁻ 4 Ω・cm S3: preparing the negative electrode sheet: preparing the negative electrode slurry, injecting the negative electrode slurry into a mold having a second corrugated surface, forming the second corrugated surface having a gradient pore structure through a gradient sintering process, baking and pressing, and demolding the sheet, and coating a second conductive transition layer on the side away from the second corrugated surface; A negative electrode slurry is prepared, and the negative electrode slurry is coated twice: the first coating is a composite slurry containing 10-30 vol% Li3BO3 with a thickness of 20-30 μm, and the second coating is a pure negative electrode active material slurry with a thickness of 80-120 μm. The negative electrode slurry is injected into a mold having a second corrugated surface, and a second corrugated surface with a gradient pore structure is formed through a gradient sintering process. The mold is then baked, pressed, and demolded, and a second conductive transition layer is coated on the side away from the second corrugated surface. The specific design is symmetrical with the positive electrode process, and the core differences include: The slurry composition is replaced with graphite (the composite layer contains 10-30 vol% Li3BO3), and the pure active material layer is graphite; After gradient sintering, the porosity of the composite layer is 40-50%, the porosity of the pure graphite layer is 10-20%, and the thermal expansion coefficient is from 11×10⁻ 6 / ℃ gradient down to 7×10⁻ 6 / ℃, matching the electrolyte layer characteristics; The second conductive transition layer uses conductive carbon black + copper-coated carbon nanotubes with a volume resistivity of ≤5×10⁻ 5 Ω・cm, enhancing electron conduction.

[0051] S4: Align the first corrugated surface of the positive electrode sheet, one side of the solid electrolyte layer, and the second corrugated surface of the negative electrode sheet in sequence, and press them together through a pressing unit to form a two-part battery; adopt a hot pressing process (temperature 60-80°C, pressure 5-10MPa) to embed the electrolyte protrusions into the high-porosity areas of the positive / negative electrodes through the self-healing layer to form a mechanical anchor. After pressing, the interface contact resistance is ≤50Ω・cm².

[0052] S5: Stack at least two of the two-part batteries, press the positive electrode current collector on the first conductive transition layer of the outermost positive electrode sheet, and press the negative electrode current collector on the second conductive transition layer of the outermost negative electrode sheet to form a battery cell; when stacking the two-part batteries, the alignment accuracy is controlled within ±10μm, and the current collector is combined with the conductive transition layer by ultrasonic pressing (power 50-100W) to form a gapless connection.

[0053] S6: Bake the battery cell at a temperature of 80-120°C for 2-4 hours. Baking at 80-120°C in a vacuum (vacuum degree ≤ 1 Pa) removes trace moisture (water content ≤ 50 ppm) and promotes interfacial wetting between the self-healing layer and the electrode / electrolyte, thereby improving long-term stability.

[0054] The above embodiments are only for illustrating the technical concept and features of the present invention. Its purpose is to enable people familiar with this technology to understand the content of the present invention and implement it. It cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A solid-state battery cell structure comprising a positive electrode sheet, a solid electrolyte layer, and a negative electrode sheet arranged in sequence; the solid electrolyte layer has a corrugated structure, characterized in that: Both sides of the solid electrolyte layer are provided with a micro-nano level bump array, and the surface of the bumps is provided with a self-repairing dynamic interface layer; The positive electrode sheet is provided with a first corrugated surface on the side facing the solid electrolyte layer that matches the corrugated structure of one side of the solid electrolyte layer, and the first corrugated surface has a gradient pore structure; the negative electrode sheet is provided with a second corrugated surface on the side facing the solid electrolyte layer that matches the corrugated structure of the other side of the solid electrolyte layer, and the second corrugated surface has a gradient pore structure; Both sides of the solid electrolyte layer are coupled to the first corrugated surface of the positive electrode sheet and the second corrugated surface of the negative electrode sheet through the micro-nano level bump array and the self-repairing dynamic interface layer.

2. The solid-state battery cell structure according to claim 1, wherein: The convex points of the micro-nano level convex point array are conical or truncated cone shaped, with a convex point height of 1-5 μm, a bottom diameter of 5-20 μm, and a spacing between adjacent convex points of 20-50 μm.

3. The solid-state battery cell structure according to claim 1, wherein: The self-repairing dynamic interface layer is a polymer layer containing reversible dynamic covalent bonds, and the thickness of the self-repairing dynamic interface layer is 50-200 nm.

4. The solid-state battery cell structure according to claim 1, wherein: The waveform structure of the solid electrolyte layer is one of a sine wave structure, a square wave structure or a triangle wave structure.

5. The solid-state battery cell structure according to claim 1, wherein: The pores in the gradient pore structure are continuously and gradually distributed from the interface side close to the solid electrolyte layer to the current collector side far away from the solid electrolyte layer. The number of pores gradually decreases as the distance from the solid electrolyte layer increases, and the overall density of the pores decreases in a step-by-step manner from the interface side to the current collector side.

6. The solid-state battery cell structure according to claim 1, wherein: The total thickness of the solid electrolyte layer is 10-100 μm, the thickness of the positive electrode sheet is 20-300 μm, and the thickness of the negative electrode sheet is 10-200 μm.

7. The solid-state battery cell structure according to claim 6, wherein: A first conductive transition layer is provided on the side of the positive electrode sheet away from the solid electrolyte layer. The first conductive transition layer is a composite layer of conductive carbon nanotubes and graphene, and has a thickness of 1-5 μm.

8. The solid-state battery cell structure according to claim 6, wherein: A second conductive transition layer is provided on the side of the negative electrode sheet away from the solid electrolyte layer. The second conductive transition layer is a composite layer of conductive carbon black and carbon fiber, and has a thickness of 1-5 μm.

9. A solid-state battery, characterized in that: The battery cell structures comprise at least two battery cell structures according to any one of claims 1 to 8, wherein the battery cell structures are stacked in sequence, and a positive electrode current collector is arranged on the outside of the first conductive transition layer of the outermost positive electrode sheet after stacking, and a negative electrode current collector is arranged on the outside of the second conductive transition layer of the outermost negative electrode sheet, the positive electrode current collector is press-connected to the first conductive transition layer, and the negative electrode current collector is press-connected to the second conductive transition layer.

10. A battery manufacturing device, characterized in that: The invention comprises a mold opening and closing unit for opening or closing an injection mold, wherein the inner wall of the mold cavity of the injection mold is provided with a micro-nano pit array matching the micro-nano level convex point array, and the mold cavity is used to form the solid electrolyte layer core of the battery core structure according to any one of claims 1 to 8; an atomic layer deposition unit, configured to deposit a shell on the surface of the core of the solid electrolyte layer, the atomic layer deposition unit comprising a precursor supply device and a vacuum reaction chamber; A pressing unit, used for pressing the positive electrode sheet, the solid electrolyte layer and the negative electrode sheet together, wherein the pressing head surface of the pressing unit is provided with a corrugated structure matching the first corrugated surface and the second corrugated surface; A coating unit is used to coat a self-repairing dynamic interface layer material on the surface of the micro-nano level convex dot array, and the coating unit adopts an aerosol jet printing device.

11. A battery manufacturing process for forming a cell structure of a solid-state battery according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: Preparation of solid electrolyte layer: Injecting molten electrolyte into the mold cavity of an injection mold, and demolding after cooling to obtain a solid electrolyte layer with a corrugated structure and a micro-nanoscale bump array; S2: Preparing a positive electrode sheet: preparing a positive electrode slurry, injecting the positive electrode slurry into a mold having a first corrugated surface, forming the first corrugated surface having a gradient pore structure through a gradient sintering process, baking and pressing, and demolding the sheet, and coating a first conductive transition layer on the side away from the first corrugated surface; S3: preparing the negative electrode sheet: preparing the negative electrode slurry, injecting the negative electrode slurry into a mold having a second corrugated surface, forming the second corrugated surface having a gradient pore structure through a gradient sintering process, baking and pressing, and demolding the sheet, and coating a second conductive transition layer on the side away from the second corrugated surface; S4: aligning the first corrugated surface of the positive electrode sheet, one side of the solid electrolyte layer, and the second corrugated surface of the negative electrode sheet in sequence, and pressing them together by a pressing unit to form a two-cell battery; S5: stacking at least two of the two-part batteries, pressing a positive electrode current collector on the first conductive transition layer of the outermost positive electrode sheet, and pressing a negative electrode current collector on the second conductive transition layer of the outermost negative electrode sheet to form a battery cell; S6: baking the battery cell at a temperature of 80-120° C. for 2-4 hours.

12. The battery manufacturing process according to claim 11, characterized in that: The gradient sintering process in step S2 and step S3 is: pre-sintering at 30-60° C. for 1-2 hours, then heating to 100-150° C. at a rate of 5-10° C. / min, and keeping warm for 2-3 hours.

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