A high-strength structured solid-state lithium battery system with a three-dimensional stacking structure

Abstract

The present invention relates to the field of solid-state lithium batteries, and specifically to a high-strength structured solid-state lithium battery system with a three-dimensional stacking structure. The present invention adopts a double-sided printed circuit substrate and introduces polymer fillers in the same layer to separate, insulate and fix single batteries, so that single batteries can be miniaturized, highly integrated, multifunctional, and integrated to form a battery system, thereby greatly improving space utilization and providing greater current, voltage and capacity for the load. In addition, the interior of the three-dimensional stacking structure battery is isolated from each other by polymer fillers, so that the battery cells have a relatively independent current network, and a certain damage does not affect the entire battery system, reducing the impact of a single battery on the battery system and improving the safety of the battery system in extreme cases such as puncture damage and large current shocks. The present invention can directly use battery cells that do not contain packaging and current collectors to further improve space utilization.

Description

Technical Field

[0001] The present invention relates to the field of solid-state lithium batteries, and specifically to a high-strength structured solid-state lithium battery system with a three-dimensional stacked structure, based on a lightweight and high-strength double-sided metallized circuit substrate. Background Art

[0002] Solid-state lithium batteries are energy storage devices whose structures contain no liquid, with all materials present in solid form. They primarily consist of a positive electrode, a negative electrode, and a solid electrolyte. They offer advantages such as high safety and high energy density, and have enormous potential for application in consumer electronics and electric transportation, such as small portable electronic products like mobile phones, digital cameras, and laptops, as well as electric vehicles like electric vehicles. With technological advancements, solid-state lithium battery devices are developing towards lightweight, flexible, and highly reinforced designs.

[0003] At present, through the optimization of materials such as the positive electrode, negative electrode, and electrolyte, the comprehensive performance of solid-state lithium batteries, such as energy density, output current / voltage, rate performance, and cycle life, has been greatly improved, and in theory, it usually has an electrochemical stability window higher than 5V. However, there are problems such as loose physical contact, grain boundary formation, and side reactions at the electrode / electrolyte interface of solid-state lithium-ion batteries, which inevitably lead to an increase in the interface impedance on both sides of the positive and negative electrodes, causing most solid-state lithium-ion batteries to exhibit lower capacity in practical applications. In particular, as the battery size increases, the uniformity of the interface reaction and internal heat generation are difficult to control, and there is a risk of thermal runaway or even explosion. Therefore, the current, voltage, and capacity that a single battery can provide are still limited and cannot meet the application requirements of some high current, high voltage, and large capacity scenarios. The output current, voltage, and capacity of solid-state lithium batteries are in urgent need of improvement. In addition, existing solid-state lithium batteries are prone to performance degradation or even failure due to interface slip under external loads, and their structural stability needs to be improved.

[0004] To improve battery performance, such as output current, voltage, and capacity, the industry currently typically uses a simple stacking device to achieve this. This involves first stacking the positive and negative electrode sheets to form a cell, which is then packaged to form a single battery. The individual batteries are then secured within a specific metal or plastic frame, and then connected in series and parallel using wire welding. While this method is simple to operate and can effectively improve the output current, voltage, and capacity of a battery pack to a certain extent, it places stringent demands on battery size and consistency, and does not fully utilize space, resulting in a low stacking density. The stacking device is also bulky, and gaps inevitably exist between the batteries. The stacking device acts more like a "shelf" for the series and parallel connection of the entire battery pack, allowing any individual battery to be added or removed from the stacking device at will. If the stacking device lacks a dedicated wire retention channel, wire tangles can occur, making battery pack management very inconvenient.

[0005] In terms of improving the stability of battery structure, on the one hand, the focus is on battery structure design in which the battery is sandwiched between strong reinforced composite materials, which is mainly responsible for mechanical bearing and does not contribute to energy storage density; on the other hand, the focus is on developing multifunctional materials that can serve as both load components and functional battery components, such as high-conductivity and high-strength carbon fiber current collector integrated negative electrodes, which usually have lower energy density. Summary of the Invention

[0006] In response to the above-mentioned problems or deficiencies, and in order to address the current solid-state lithium battery system's requirements for large output current, high output voltage, high energy density, and high strength, the present invention provides a high-strength structured solid-state lithium battery system with a three-dimensional stacking structure. Based on a lightweight and high-strength double-sided metallized circuit substrate, the solid-state lithium battery is embedded in the double-sided metallized circuit substrate. The in-plane printed circuit of the circuit substrate is used to achieve customized connections of multiple solid-state lithium batteries within the substrate surface, and the metallized through-holes of the circuit substrate are used to achieve longitudinal connections between multiple solid-state lithium batteries between substrates, thereby constructing a high-density and high-strength solid-state lithium battery system with a three-dimensional stacking structure, which outputs the current and voltage required by the load on demand. At the same time, the solid-state lithium battery system can also bear mechanical forces and can be used as a structural component to further reduce the weight of the equipment system, thereby improving the operating time of the equipment.

[0007] A high-strength structured solid-state lithium battery system with a three-dimensional stacking structure includes a circuit substrate, a solid-state lithium battery layer, a substrate film / positive and negative electrode current collectors, and a packaging shell.

[0008] The circuit substrate is a double-sided circuit printed substrate, with n≥1. The upper and lower surfaces of the circuit substrate are respectively printed with patterned current collectors corresponding to the positive / negative electrodes of each solid-state lithium battery in the same layer, so that the positive electrodes and positive electrodes, and the negative electrodes and negative electrodes of each solid-state lithium battery in the same layer are connected in the upper and lower surfaces of the circuit substrate.

[0009] Furthermore, the current collectors on both sides of the circuit substrate are provided with metallized through-holes for longitudinal electrical connectivity between the layers of the solid-state lithium battery. It should be noted that, taking into account the characteristics of the solid-state lithium battery itself and the three-dimensional stacking structure proposed by the present invention, the circuit substrate used in the present invention is a double-sided circuit printed substrate, unlike the single-sided substrate circuit printing in the conventional chip three-dimensional stacking process, and the metallized through-holes are provided at the offset of the patterned current collectors on the upper and lower surfaces of the circuit substrate, that is, the metallized through-holes do not penetrate the current collectors on the upper and lower surfaces at the same time.

[0010] The substrate film / positive and negative electrode current collector is a single-sided printed substrate, which is divided into a first-layer substrate film / positive electrode current collector and a bottom-layer substrate film / negative electrode current collector, and is used for in-plane connection of the first-layer and bottom-layer batteries.

[0011] The solid-state lithium battery layer has n+1 layers, with at least 2 solid-state lithium batteries in each layer. The solid-state lithium battery layers are separated by circuit substrates, and polymer fillers are filled between adjacent solid-state lithium batteries in the same layer to provide support and protection for each solid-state lithium battery; the patterned current collectors on the upper and lower sides of each circuit substrate are respectively in contact with the positive or negative pole of each solid-state lithium battery on the corresponding contact side.

[0012] The solid-state lithium battery layer and the circuit substrate are alternately stacked in sequence, with the solid-state lithium battery layer as the outermost layer, and then the entire stacked structure is packaged through the packaging shell to complete the packaging of the entire solid-state lithium battery system. The upper current collector of the first-layer circuit substrate is connected to the substrate film / positive current collector of the first-layer battery by welding its metallized through-holes with the wires in the upper layer of polymer filler; the lower current collector of the first-layer circuit substrate is also connected to the negative current collector of the next layer of battery by welding its metallized through-holes with the wires in the next layer of polymer filler, and circulates downward to connect the positive and negative current collectors of each layer in turn until it is connected to the substrate film / negative current collector of the bottom battery, thereby completing the three-dimensional stacking integration of the entire battery system. In addition, the substrate film / positive current collector of the first-layer battery is led out with a wire as the positive electrode of the entire solid-state lithium battery system, and the substrate film / negative current collector of the bottom battery is led out with a wire as the negative electrode of the entire solid-state lithium battery system.

[0013] In the present invention, cross-layer electrical interconnection of current collector strips on the upper and lower sides of each circuit substrate is achieved through metallized through-holes of each circuit substrate and wires arranged in polymer fillers, while effectively avoiding short circuit between the positive and negative electrodes of the single battery.

[0014] Furthermore, the polymer filler is epoxy resin, polyethylene or polypropylene.

[0015] Furthermore, the packaging shell is a high water and oxygen barrier film, which is realized by a thin film packaging process.

[0016] Furthermore, the wire material is Al, Au, Ag, Cu or Ni.

[0017] Furthermore, the solid-state lithium battery is a cell battery without a packaging shell and a current collector, so as to improve the space utilization of the entire three-dimensional stacked structure solid-state lithium battery system.

[0018] Furthermore, the circuit substrate is a polymer film modified with a patterned highly conductive material (i.e., a circuit substrate printed with a patterned current collector), wherein the conductive material of the patterned current collector on the positive electrode side is Al, Au or stainless steel, the conductive material of the patterned current collector on the negative electrode side is Cu, Ni, Au or stainless steel, and the polymer film is polyimide, polyethylene or polystyrene.

[0019] Furthermore, the solid-state lithium battery and the circuit substrate are fixed by bonding or constructing a limiting structure between the two.

[0020] When the high-strength structured solid-state lithium battery system of the present invention is in operation, it is only necessary to connect the positive and negative electrode interfaces of the battery system to the load respectively to form a closed loop, thereby supplying energy to the load.

[0021] In the present invention, a three-dimensional stacking integration process is used to connect single cells. By using a double-sided printed circuit substrate and introducing polymer fillers in the same layer to separate, insulate and fix the single cells, the mechanical strength is high and the space utilization rate is extremely high. Specifically, it involves TGV perforation technology and thermal ultrasonic welding technology, which enables the single cells to be miniaturized, highly integrated, multifunctional, and integrated to form a battery system, thereby greatly improving the space utilization rate and providing greater current, voltage and capacity for the load. In addition, the three-dimensional stacked structure batteries are isolated from each other by polymer fillers, resulting in the battery cells having a relatively independent current network. A certain damage does not affect the entire battery system, reducing the impact of a single battery on the battery system and improving the safety of the battery system in extreme situations such as puncture damage and large current shocks. The present invention can directly use battery cells that do not contain packaging and current collectors to further improve space utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the process flow of the present invention;

[0023] Figure 2 Schematic diagram of the structure of a high-strength structured solid-state lithium battery system fixed with adhesive in an embodiment;

[0024] Figure 3 Schematic diagram of the structure of an embedded fixed high-strength structured solid-state lithium battery system in an embodiment;

[0025] Figure 4 Schematic diagram of adhesive fixing TGV perforation, wire welding and polymer filler in the embodiment;

[0026] Figure 5 Schematic diagram of embedded fixed TGV perforation, wire welding and polymer filler in the embodiment;

[0027] Figure 6 This is a top view of a polymer thin film circuit substrate and a battery cell modified with a patterned highly conductive material in an embodiment;

[0028] Figure 7 Schematic diagram of the structure of a solid-state lithium battery cell in an embodiment;

[0029] Figure markings: 1-substrate film, 2-circuit substrate negative electrode current collector bar, 3-circuit substrate positive electrode current collector bar, 4-through hole for conducting the negative electrode current collector bar, 5-through hole for conducting the positive electrode current bar, 6, 7-integral circuit substrate, 8 to 16-solid-state lithium battery, 17-first layer substrate film / positive electrode current collector, 18-bottom layer substrate film / negative electrode current collector, 19 to 22-metal welding wires, 23-positive electrode external circuit connection of three-dimensional stacked structure solid-state lithium battery system, 24-negative electrode external circuit connection of three-dimensional stacked structure solid-state lithium battery system, 25-polymer filler, 26-high water and oxygen barrier packaging film, 27-solid-state lithium battery cell positive electrode, 28-solid-state lithium battery cell diaphragm, 29-solid-state lithium battery cell negative electrode, 30-solid-state lithium battery cell. DETAILED DESCRIPTION

[0030] In order to clearly demonstrate the purpose, technical solutions and advantages of the present invention, the present invention is further described in detail below with reference to specific embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0031] It should be noted that the illustrations provided in this embodiment are only schematic illustrations of the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complex.

[0032] like Figure 1As shown, this embodiment provides a preparation method for a high-strength structured solid-state lithium battery system with a three-dimensional stacked structure, using a circuit substrate with collector strips printed in an offset manner as a supporting and separating skeleton, using TGV perforation technology to make through-holes in the circuit substrate, filling the through-holes with highly conductive metal to achieve circuit conduction of the collector strips on the front and back sides of the circuit substrate, using current collector plates to respectively achieve connection and conduction in the first positive electrode layer of the three-dimensional stacked battery and the bottom negative electrode layer of the battery, using a thermal ultrasonic welding process to achieve orderly connection and conduction between the positive and negative collector strips on the internal circuit substrate of the battery and the substrate films / positive and negative collectors of the first and last layers, using a thermal ultrasonic welding process to lead out the positive and negative external circuit connectors of the three-dimensional stacked battery pack from the substrate films / positive and negative collectors of the first and last layers, using a polymer filling process to fill, fix and seal the internal gaps of the battery and the sides of the three-dimensional stacked battery pack, and encapsulate the battery with an aluminum-plastic film to finally form a three-dimensional stacked solid-state lithium battery system.

[0033] like Figures 2 to 6 , illustrating the specific structure and important structural details of the high-strength structured solid-state lithium battery system prepared in this embodiment. A substrate film 1 is provided, with negative electrode current collector strips 2 and positive electrode current collector strips 3 printed in staggered patterns on the upper and lower surfaces of the substrate film 1. The substrate film 1 is made of polystyrene (PS), the negative electrode current collector strips 2 are made of Cu, and the positive electrode current collector strips 3 are made of Al.

[0034] On the substrate film 1, TGV perforation technology and thermosonic bonding are used to achieve cross-layer electrical interconnection between the upper and lower current collector strips, effectively preventing short circuits between the positive and negative electrodes of the single cell. Two through-holes 4 and 5 are formed at corresponding locations corresponding to the negative and positive current collector strips 2 and 3, and are filled with highly conductive metal, with solder joints prepared. This completes the overall preparation process for the two circuit substrates 6 and 7 shown in the figure. The highly conductive metal filled in through-holes 4 and 5 is Al.

[0035] Solid-state lithium batteries 8 to 16 are provided, and the two circuit substrates 6 and 7 are used as a supporting framework. Solid-state lithium batteries 8 to 16 and circuit substrates 6 and 7 are three-dimensionally stacked and assembled. Solid-state lithium batteries 8, 9, and 10 serve as the first layer, with their negative electrodes connected and conducted via the negative electrode current collector strip on the upper surface of circuit substrate 6. Solid-state lithium batteries 11, 12, and 13 serve as the middle layer, with their positive electrodes connected and conducted via the positive electrode current collector strip on the lower surface of circuit substrate 6, and their negative electrodes connected and conducted via the negative electrode current collector strip on the upper surface of circuit substrate 7. Solid-state lithium batteries 14, 15, and 16 serve as the bottom layer, with their positive electrodes connected and conducted via the positive electrode current collector strip on the lower surface of circuit substrate 7. Solid-state lithium batteries 8 to 16 are conventional batteries with uniform specifications, but no excessive restrictions are placed on the specific parameters of the individual cells. Figure 2 、 3, 6 The solid-state lithium battery referred to by numbers 8 to 16 is 30-solid-state lithium battery cell, including: 27-solid-state lithium battery cell positive electrode, 28-solid-state lithium battery cell separator, 29-solid-state lithium battery cell negative electrode.

[0036] Specifically, the fixation between the single cells and the circuit substrate in the same layer can be achieved in two ways: first, by using adhesive to achieve strong bonding between the single cells and the substrate; second, by constructing a limiting structure to embed the single cells on the circuit substrate.

[0037] Provide a first-layer substrate film / positive electrode current collector 17 and a bottom-layer substrate film / negative electrode current collector 18. Connect the positive electrodes of the first-layer solid-state lithium batteries 8, 9, and 10 to 17, and connect the negative electrodes of the bottom-layer solid-state lithium batteries 14, 15, and 16 to 18. The substrate film / positive and negative electrode current collectors are current collectors printed on one side of the substrate film. The positive electrode current collector is Al, and the negative electrode current collector is Cu film.

[0038] The wire bonding process is used to connect the current collector strips of the conductive circuit substrates 6 and 7 and the substrate films / current collectors 17 and 18 respectively through metal bonding wires 19, 20, 21 and 22.

[0039] Specifically, one end of the metal welding wire 19 is connected to the welding point on the substrate film / positive electrode collector 17, and the other end of the metal welding wire 19 is connected to the through-hole welding point reserved on the upper surface of the circuit substrate 6 (the welding point has been connected to the positive electrode collector strip on the lower surface of the circuit substrate 6 through the highly conductive metal filler inside the through-hole); one end of the metal welding wire 20 is connected to the welding point of the positive electrode collector strip on the lower surface of the circuit substrate 6, and the other end of the metal welding wire 20 is connected to the through-hole welding point reserved on the upper surface of the circuit substrate 7 (the welding point has been connected to the positive electrode collector strip on the lower surface of the circuit substrate 7 through the highly conductive metal filler inside the through-hole ); one end of the metal bonding wire 21 is connected to a solder point on the substrate film / negative electrode current collector 18, and the other end of the metal bonding wire 21 is connected to a through-hole solder point reserved on the lower surface of the circuit substrate 7 (the solder point is already connected to the negative electrode current collector strip on the upper surface of the circuit substrate 7 through the highly conductive metal filler inside the through-hole). One end of the metal bonding wire 22 is connected to a solder point on the negative electrode current collector strip on the upper surface of the circuit substrate 7, and the other end of the metal bonding wire 22 is connected to a through-hole solder point reserved on the lower surface of the circuit substrate 6 (the solder point is already connected to the negative electrode current collector strip on the upper surface of the circuit substrate 6 through the highly conductive metal filler inside the through-hole). The bonding process can be a thermosonic bonding process, and the length of the metal bonding wire can be selected and adjusted as needed, without excessive limitation.

[0040] Furthermore, the metal bonding wires 19 , 20 , 21 , 22 , 23 , and 24 are made of inexpensive Cu wires to reduce costs.

[0041] Using the wire bonding process, the positive and negative external circuit connections of the three-dimensional stacked battery system are led out from the substrate film / positive electrode current collector 17 and the substrate film / negative electrode current collector 18 through metal bonding wires 23 and 24 respectively.

[0042] A polymer filling process is used to fill, fix and seal the internal gaps and surrounding areas of the three-dimensional stacked battery system with a polymer filler 25. The polymer filler 25 is polypropylene.

[0043] The thin film encapsulation process is used to fully encapsulate the three-dimensional stacked battery system through a high water and oxygen barrier film 26.

[0044] From the above examples, it can be seen that the present invention adopts a double-sided printed circuit substrate and introduces polymer fillers in the same layer to separate, insulate and fix the single cells, so that the single cells can be miniaturized, highly integrated, multifunctional, and integrated to form a battery system, thereby greatly improving space utilization and providing greater current, voltage and capacity for the load. In addition, the three-dimensional stacked structure batteries are isolated from each other by polymer fillers, resulting in a relatively independent current network for the battery cells, reducing the impact of a single battery on the entire battery system and improving the safety of the battery system in extreme situations such as puncture damage and high current shocks; and the present invention can directly use battery cells that do not contain packaging and current collectors for stacking and integration, further improving space utilization.

Claims

1. A high-strength structured solid-state lithium battery system with a three-dimensional stacked structure, characterized by: Including circuit substrate, solid-state lithium battery layer, substrate film / positive and negative electrode current collectors and packaging shell; The circuit substrate is a double-sided circuit printed substrate, with n ≥ 1, and patterned current collectors corresponding to the positive / negative electrodes of each solid-state lithium battery in the same layer are printed on the upper and lower surfaces of the circuit substrate, respectively, so that the positive electrodes and positive electrodes, and the negative electrodes and negative electrodes of each solid-state lithium battery in the same layer are connected within the upper and lower surfaces of the circuit substrate respectively; metallized through-holes are provided on the current collectors on both sides of the circuit substrate, and the metallized through-holes are provided at the staggered positions of the patterned current collectors on the upper and lower surfaces of the circuit substrate; the metallized through-holes provided on the negative electrode current collector on the upper surface of the circuit substrate are conductively connected to the positive electrode current collector on the lower surface of the circuit substrate, and the metallized through-holes provided on the positive electrode current collector on the lower surface of the circuit substrate are conductively connected to the negative electrode current collector on the upper surface of the circuit substrate; The substrate film / positive and negative electrode current collector is a single-sided printed substrate, divided into a first-layer substrate film / positive electrode current collector and a bottom-layer substrate film / negative electrode current collector, which is used for in-plane connection of the first-layer and bottom-layer batteries; The solid-state lithium battery layer has n+1 layers, with at least two solid-state lithium batteries in each layer. The solid-state lithium battery layers are separated by circuit substrates, and polymer fillers are filled between adjacent solid-state lithium batteries in the same layer. The patterned current collectors on the upper and lower sides of each circuit substrate are respectively in contact with the positive electrode or negative electrode of each solid-state lithium battery on the corresponding contact side. The solid-state lithium battery layer and the circuit substrate are alternately stacked in sequence, with the solid-state lithium battery layer as the outermost layer, and then the entire stacked structure is packaged through a packaging shell to complete the packaging of the entire solid-state lithium battery system; the upper current collector of the first-layer circuit substrate is connected to the substrate film / positive electrode current collector of the first-layer battery by welding the wire in the upper layer of polymer filler through its metallized through-hole; the lower current collector of the first-layer circuit substrate is also connected to the negative electrode current collector plate of the next layer of battery by welding the wire in the next layer of polymer filler through its metallized through-hole, and circulates downward to connect the positive and negative electrode current collector plates of each layer in turn until it is connected to the negative electrode current collector plate of the bottom battery, so as to complete the three-dimensional stacking integration of the entire battery system; and the substrate film / positive electrode current collector of the first-layer battery is led out by a wire as the positive electrode of the entire solid-state lithium battery system, and the substrate film / negative electrode current collector of the bottom battery is led out by a wire as the negative electrode of the entire solid-state lithium battery system.

2. The high-strength structured solid-state lithium battery system of the three-dimensional stacked structure as claimed in claim 1, characterized in that: The polymer filler is epoxy resin, polyethylene or polypropylene.

3. The high-strength structured solid-state lithium battery system of the three-dimensional stacked structure as claimed in claim 1, characterized in that: The packaging shell is a high water and oxygen barrier film, which is realized by a thin film packaging process.

4. The high-strength structured solid-state lithium battery system of the three-dimensional stacked structure as claimed in claim 1, characterized in that: The wire material is Al, Au, Ag, Cu or Ni.

5. The high-strength structured solid-state lithium battery system of the three-dimensional stacked structure as claimed in claim 1, characterized in that: The solid-state lithium battery is a cell battery without a packaging shell and a current collector, so as to improve the space utilization rate of the entire three-dimensional stacked structure solid-state lithium battery system.

6. The high-strength structured solid-state lithium battery system of the three-dimensional stacked structure as claimed in claim 1, characterized in that: The circuit substrate is a polymer film modified with a patterned highly conductive material, wherein the conductive material of the patterned current collector on the positive electrode side is Al, Au or stainless steel, the conductive material of the patterned current collector on the negative electrode side is Cu, Ni, Au or stainless steel, and the polymer film is polyimide, polyethylene or polystyrene.

7. The high-strength structured solid-state lithium battery system of the three-dimensional stacked structure as claimed in claim 1, characterized in that: The solid-state lithium battery and the circuit substrate are fixed by bonding or constructing a limiting structure between the two.

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