Battery cell, battery module and preparation method thereof, and battery pack

Abstract

The invention provides a battery cell, a battery module and a preparation method thereof, and a battery pack, and belongs to the technical field of batteries, the battery cell comprises a plurality of first positive electrode assemblies stacked in sequence, and the first positive electrode assemblies comprise solid electrolyte layers; the negative electrode assembly comprises a conductive part made of a flexible conductive material; wherein the conductive part is bent and extends along the stacking direction of the first positive electrode assemblies to form a plurality of accommodating spaces, any two adjacent accommodating spaces are separated from each other, one first positive electrode assembly is placed in each accommodating space, and the solid electrolyte layer in each first positive electrode assembly is in contact with at least one space wall of the accommodating space to realize electric connection; therefore, one negative electrode assembly is electrically connected with the plurality of first positive electrode assemblies. The lithium ion battery has the advantages that the conductive part is bent to form a plurality of connecting sections which are in physical contact and electric connection with the solid electrolyte in each first positive electrode assembly respectively, so that the connection between one negative electrode assembly and a plurality of positive electrode assemblies is realized, and the use amount of a negative electrode material is greatly reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a battery cell, a battery module and a preparation method thereof and a battery pack. BACKGROUND

[0002] With the continuous growth of the demand for high energy density and high safety power supply in new energy vehicles, intelligent terminal devices and large-scale energy storage systems, traditional liquid lithium ion batteries are facing physical limits in terms of energy density improvement, thermal stability guarantee and cycle life extension. Under this background, all-solid-state batteries, which use solid electrolyte to replace flammable and volatile organic liquid electrolyte and porous separator, have become an important development direction of the next generation of high-performance battery technology.

[0003] At present, the manufacturing process of most solid-state batteries still follows the laminated or wound structure of traditional liquid lithium batteries, and usually adopts the way of stacking each layer of "positive electrode / electrolyte film / negative electrode" for assembly. However, when applied to all-solid-state battery systems, this method exposes limitations: each layer of electrochemical cell needs to be independently configured with negative electrode material, which leads to repeated use of negative electrode components, serious waste of materials, and increases the overall weight and volume, which is not conducive to improving energy density; secondly, when multiple series and parallel battery modules need to be built, the traditional way often relies on the external connection of multiple independent battery cells, which not only needs to set negative electrode tabs and negative electrode materials for each battery cell, but also needs to additionally configure busbars and perform multiple welding or riveting on each positive and negative electrode tab, resulting in complicated process and rising cost. SUMMARY

[0004] The purpose of the present application is to solve the above-mentioned problems existing in the prior art, and to provide a solid-state battery with simple structure and convenient production.

[0005] The purpose of the present application can be achieved by the following technical scheme: a battery cell, comprising:

[0006] a plurality of first positive electrode assemblies stacked in sequence, the first positive electrode assembly comprising a solid-state electrolyte layer;

[0007] a negative electrode assembly comprising a conductive part made of a flexible conductive material;

[0008] wherein the conductive part is bent and extended along the stacking direction of the first positive electrode assembly to form a plurality of accommodation spaces, any two adjacent accommodation spaces are separated from each other, one first positive electrode assembly is placed in each accommodation space, the solid-state electrolyte layer in each first positive electrode assembly is in contact with at least one space wall of the accommodation space to realize electrical connection, so as to realize electrical connection between the negative electrode assembly and the plurality of first positive electrode assemblies.

[0009] In one of the aforementioned battery cells, the first positive electrode assembly further includes a positive electrode current collector layer, which is stacked with the solid electrolyte layer. A portion of the positive electrode current collector layer extends outward to form a first positive electrode tab, and all the first positive electrode tabs on the first positive electrode assembly are electrically connected to each other.

[0010] In one of the aforementioned battery cells, each of the first positive electrode components includes two solid electrolyte layers, and both solid electrolyte layers are connected to the conductive portion.

[0011] In one of the aforementioned battery cells, the first positive electrode assembly includes a first solid electrolyte layer, a first positive electrode material layer, a first positive electrode current collector layer, a second positive electrode material layer, and a second solid electrolyte layer stacked sequentially, with a portion of the first positive electrode current collector layer extending outward to form a first positive electrode tab.

[0012] In one of the aforementioned battery cells, the negative electrode assembly further includes a negative electrode current collector layer and a negative electrode material layer. The conductive portion and the negative electrode material layer are both disposed on the negative electrode current collector layer, and a portion of the negative electrode current collector layer extends outward to form a negative electrode tab.

[0013] In one of the aforementioned battery cells, an insulating frame is provided on the side of the first positive electrode assembly along the thickness direction to prevent the conductive part from contacting other components in the first positive electrode assembly except for the solid electrolyte layer; a portion of the positive current collector layer in the first positive electrode assembly extends out of the insulating frame to form a first positive electrode tab.

[0014] In one of the aforementioned battery cells, a second positive electrode assembly is further included. An insulating frame is provided on the side of the second positive electrode assembly, and a conductive layer is provided on the top of the second positive electrode assembly. The second positive electrode assembly is stacked on top of the first positive electrode assembly and connected to the conductive portion.

[0015] In one of the aforementioned battery cells, the second positive electrode assembly includes a second positive electrode current collector layer, a third positive electrode material layer, and a third solid electrolyte layer stacked sequentially. The conductive layer is located on the second positive electrode current collector layer, and the third solid electrolyte layer is connected to the conductive portion to achieve electrical connection. A portion of the second positive electrode current collector layer extends outward to form a second positive electrode tab, and the second positive electrode tab is electrically connected to all the first positive electrode tabs.

[0016] A battery module includes the aforementioned battery cell and an expanded capacity battery cell. The expanded capacity battery cell includes a negative electrode portion made of a flexible negative electrode material and at least one third positive electrode assembly stacked together. The third positive electrode assembly includes a fourth solid electrolyte layer. The negative electrode portion is fixed on the conductive layer. After being connected and bent along the stacking direction of the third positive electrode assembly, the negative electrode portion contacts the fourth fixed electrolyte layer in the corresponding third positive electrode assembly to achieve electrical connection.

[0017] A battery pack comprising the aforementioned battery cells or the aforementioned battery modules.

[0018] A method for manufacturing a battery cell, used in the aforementioned battery cell, includes the following steps:

[0019] S1. Fabricate at least one first positive electrode component;

[0020] S2. Fabricate a negative electrode assembly including a conductive part;

[0021] S3. Place a fabricated first positive electrode component on the negative electrode component, and bend the conductive part to cover the first positive electrode component;

[0022] S4. Place another first positive electrode assembly on the first positive electrode assembly, and continue to bend the conductive part so that it covers the other first positive electrode assembly;

[0023] S5. Repeat step S4 until the preset battery capacity is reached, then cut off the conductive part.

[0024] S6. Connect the positive electrode tabs of all the first positive electrode components stacked in the above steps.

[0025] A method for manufacturing a battery module, used in the aforementioned battery module, includes the following steps:

[0026] S1. Fabricate a second positive electrode assembly with a conductive layer, and at least one first positive electrode assembly, a third positive electrode assembly, and a negative electrode portion;

[0027] S2. Fabricate a negative electrode assembly including a conductive part;

[0028] S3. Place a fabricated first positive electrode component on the negative electrode component, and bend the conductive part to cover the first positive electrode component;

[0029] S4. Place another first positive electrode assembly on top of the first positive electrode assembly, and continue to bend the conductive part so that it covers the other first positive electrode assembly.

[0030] S5. Repeat S4 until the preset battery capacity is reached, and make the conductive part cover the topmost first positive electrode component, and cut off the conductive part.

[0031] S6. Stack the second positive electrode assembly on the top conductive part in step S5 above. The third solid electrolyte layer in the second positive electrode assembly is connected to the conductive part. Place the negative electrode part on the conductive layer of the second positive electrode assembly. Place a fabricated third positive electrode assembly on the negative electrode part. Bend the negative electrode part so that it covers the third positive electrode assembly. Repeat the above-mentioned placement of the third positive electrode assembly and bending of the negative electrode part until the preset battery capacity is reached. Cut off the negative electrode part.

[0032] S7. Connect the second positive electrode assembly stacked in the above steps to the positive electrode tabs of all the first positive electrode assemblies, and connect the positive electrode tabs of the third positive electrode assembly to the positive electrode assemblies.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] (1) The first positive electrode assembly integrates a solid electrolyte layer and adopts a negative electrode assembly including a conductive part. The conductive part is bent to form multiple accommodating spaces, which are physically contacted and electrically connected to the solid electrolyte in each of the first positive electrode assemblies, so as to realize the series connection between one negative electrode assembly and multiple positive electrode assemblies. This greatly reduces the amount of negative electrode materials (such as lithium metal, silicon-carbon composite materials and other high-cost materials) used and avoids the structural redundancy caused by multi-layer negative electrodes. The bending path of the flexible conductive part can be precisely controlled to achieve tight fit between multi-level electrodes, reduce the internal gap and ineffective volume of the battery, help improve the energy density per unit volume, and also greatly reduce the number of process steps and connectors in the battery assembly process.

[0035] (2) Moreover, since the first positive electrode component integrates a solid electrolyte layer and the negative electrode component directly contacts and conducts through the flexible conductive part, the entire cell does not involve liquid electrolyte, thus avoiding the risks of leakage, volatilization and thermal runaway. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of the first positive electrode component;

[0037] Figure 2 yes Figure 1 A schematic diagram of the cross-sectional structure;

[0038] Figure 3 This is a cross-sectional structural diagram of the negative electrode assembly;

[0039] Figure 4 This is a schematic diagram of the structure of the second positive electrode component;

[0040] Figure 5 yes Figure 4 A schematic diagram of the cross-sectional structure;

[0041] Figure 6This is a schematic diagram of the assembly and connection of the first positive electrode component and the negative electrode component;

[0042] Figure 7 This is a schematic diagram of a single battery cell.

[0043] Figure 8 Is Figure 7 A schematic diagram of the structure with a second positive electrode component added;

[0044] Figure 9 yes Figure 8 A schematic diagram of the assembly and connection with the first positive electrode component in the expanded capacity battery cell;

[0045] Figure 10 This is a schematic diagram of the third positive electrode component;

[0046] Figure 11 This is a schematic diagram of another embodiment of the negative electrode component.

[0047] In the figure, 100 is the first positive electrode assembly; 101 is the first solid electrolyte layer; 102 is the first positive electrode material layer; 103 is the first positive electrode current collector layer; 104 is the second positive electrode material layer; 105 is the second solid electrolyte layer; 106 is the insulating frame; 107 is the first positive electrode tab; 200 is the negative electrode assembly; 201 is the negative electrode current collector layer; 202 is the negative electrode material layer; 203 is the conductive part; 204 is the accommodating space; 205 is the negative electrode tab; 300 is the second positive electrode assembly; 301 is the second positive electrode current collector layer; 302 is the third positive electrode material layer; 303 is the third solid electrolyte layer; 304 is the conductive layer; 305 is the second positive electrode tab; 400 is the third positive electrode assembly; and 401 is the negative electrode part. Detailed Implementation

[0048] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0049] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0050] like Figures 1-9 As shown, a battery cell includes:

[0051] Multiple first positive electrode components 100 are stacked sequentially, each first positive electrode component including a solid electrolyte layer;

[0052] The negative electrode assembly 200 includes a conductive portion 203 made of a flexible conductive material; wherein the conductive portion 203 is bent and extended along the stacking direction of the first positive electrode assembly to form a plurality of receiving spaces 204, any two adjacent receiving spaces 204 are separated from each other, a first positive electrode assembly is placed in each receiving space 204, and the solid electrolyte layer in each first positive electrode assembly 100 contacts at least one space wall of the receiving space 204 to achieve electrical connection, so as to realize the electrical connection between one negative electrode assembly 200 and the plurality of first positive electrode assemblies 100.

[0053] The first positive electrode assembly 100 provided by this invention integrates a solid electrolyte layer, and simultaneously employs a negative electrode assembly 200 including a conductive part 203. The conductive part 203 is bent to form multiple accommodating spaces 204, which respectively achieve physical contact and electrical connection with the solid electrolyte in each of the first positive electrode assemblies 100, so as to realize the series connection between one negative electrode assembly 200 and multiple positive electrode assemblies. This significantly reduces the amount of negative electrode materials (such as high-cost materials such as lithium metal and silicon-carbon composite materials) used, and avoids the structural redundancy caused by multi-layer negative electrodes. The bending path of the flexible conductive part 203 can be precisely controlled to achieve tight fit between multi-level electrodes, reduce the internal voids and ineffective volume of the battery, help improve the energy density per unit volume, and also significantly reduce the number of process steps and connectors in the battery assembly process.

[0054] Furthermore, since the first positive electrode component 100 integrates a solid electrolyte layer, and the negative electrode component 200 directly contacts and conducts with the solid electrolyte layer through the flexible conductive part 203, the entire cell is free of liquid electrolyte, thus avoiding the risks of leakage, volatilization, and thermal runaway.

[0055] Furthermore, the first positive electrode assembly 100 also includes a positive electrode current collector layer, which is stacked with a solid electrolyte layer. A portion of the positive electrode current collector layer extends outward to form a first positive electrode tab 107. All the first positive electrode tabs 107 on the first positive electrode assembly 100 are electrically connected to each other by crimping or welding. Thus, after the battery is packaged, only a unified positive electrode tab and a negative electrode tab 205 on the negative electrode assembly 200 need to be led out as external electrical output terminals, which greatly simplifies the electrical connection structure with external circuits or battery management systems and significantly reduces wiring complexity and system integration difficulty.

[0056] Meanwhile, all the first positive electrode components 100 are connected in parallel through the first positive electrode tabs 107 extending from the positive electrode current collector layer, so that each positive electrode unit is at the same potential and the current distribution is uniform, which improves the overall charging and discharging consistency and power output capability of the battery; this parallel structure also enables the solid-state cells to be highly integrated and together form a large-capacity single cell.

[0057] like Figures 1-2As shown, specifically, the first positive electrode component 100 adopts a symmetrical multilayer structure design, including a first solid electrolyte layer 101, a first positive electrode material layer 102, a first positive electrode current collector layer 103, a second positive electrode material layer 104, and a second solid electrolyte layer 105 stacked sequentially. This structure uses the positive electrode current collector layer (such as a metal foil with good conductivity and high oxidation potential, like aluminum foil, used to carry and conduct electrons, and is soft and low-cost) as the core support layer. On both sides of the current collector layer, positive electrode material layers of the same area (such as positive electrode slurries containing lithium nickel cobalt manganese oxide, lithium iron phosphate, etc.) are coated, laminated, or cured. A dense solid electrolyte layer (such as a sulfide, oxide, or polymer-based solid electrolyte) is further covered on the outer surface of each positive electrode material layer. This constructs a double-sided electrochemical reaction interface, allowing each first positive electrode component 100 to simultaneously participate in lithium-ion insertion / extraction reactions and electron conduction processes in two directions, thereby significantly enhancing the battery's volumetric capacity and energy density.

[0058] like Figure 3 As shown, the negative electrode assembly 200 includes a negative electrode current collector layer 201 and a negative electrode material layer 202 (such as carbon-based materials, silicon-based materials, lithium metal, and alloys). The negative electrode current collector layer 201 can be made of a metal foil with good conductivity and mechanical strength, such as copper or nickel foil, to carry and conduct electrons. A portion of the negative electrode current collector layer 201 extends along its length to form a negative electrode tab 205, which serves as a current output terminal for electrical connection with other components during subsequent battery assembly. Simultaneously, a reinforcing material layer (such as carbon fiber, graphene / graphene oxide, etc.) can be added to the negative electrode current collector layer 201 or the negative electrode material layer 202 to enhance the overall mechanical strength of the entire negative electrode assembly 200. The conductive portion 203 is located on the negative electrode current collector layer 201 and is made of a flexible conductive material (such as metal foil strip). Figure 11 As shown, furthermore, the negative electrode material layer 202 and the conductive part 203 are made of the same material and are integrally formed (such as metal foil strip). The conductive part 203 is designed to be flexible, so that its shape can be adjusted as needed during the stacking process to ensure close contact with the solid electrolyte layer in the adjacent first positive electrode assembly 100, thereby achieving an effective electron conduction path.

[0059] A further improvement of the present invention is that, along the thickness direction of the first positive electrode assembly 100, an insulating frame 106 is provided on the side of the first positive electrode assembly 100 to prevent the conductive part 203 from contacting other components in the first positive electrode assembly 100 except for the solid electrolyte layer; a portion of the positive current collector layer in the first positive electrode assembly 100 extends out of the insulating frame 106 to form a first positive electrode tab 107. The insulating frame 106 surrounds the side of the positive electrode assembly, covering the side of the multilayer stacked structure formed by the first solid electrolyte layer 101, the first positive electrode material layer 102, the first positive current collector layer 103, the second positive electrode material layer 104, and the second solid electrolyte layer 105, exposing only a specific area of ​​the positive current collector to form the first positive electrode tab 107, thereby achieving electrical isolation between the multilayer solid electrode bodies.

[0060] The insulating frame 106 can be made of materials with high insulation, good adhesion and certain mechanical strength, such as thermosetting resin, epoxy adhesive, polyimide (PI) or ceramic-polymer composite material. It is formed around the thickness direction of the first positive electrode component 100 by printing, molding or spraying process, and fills the tiny gaps that may exist between the layers of material, thereby improving the compactness and mechanical stability of the overall structure.

[0061] like Figures 4-5 As shown, to avoid damage, breakage, or short circuit risks caused by friction, compression, or mechanical impact between the exposed conductive part 203 at the top of the battery cell and the inner wall of the casing during battery pack assembly, when the battery cell is placed into the metal or rigid battery casing, this invention further adds a second positive electrode assembly 300 on top of the first positive electrode assembly 100. An insulating frame 106 is also provided on the side of the second positive electrode assembly 300 in the thickness direction. This insulating frame 106 not only serves as physical isolation to prevent lateral short circuits during battery cell stacking or casing assembly, but also provides a precise positioning reference surface for automated stacking, ensuring the alignment accuracy of each layer of components. A conductive layer 304 is provided on the top of the second positive electrode assembly 300. This conductive layer 304 is typically made of highly conductive metal foil (such as aluminum foil or copper foil) and is firmly attached to the surface of the second positive electrode assembly 300 using conductive adhesive or other adhesives. The design of the conductive layer 304 allows the second positive electrode assembly 300 to function as both a protective layer and an electrical connection.

[0062] The structure of the second positive electrode assembly 300 includes a second positive electrode current collector layer 301, a third positive electrode material layer 302, and a third solid electrolyte layer 303 covering its outer surface. A portion of the second positive electrode current collector layer 301 (such as aluminum foil) extends outward as a second positive electrode tab 305. When it is located on the battery cell, its exposed solid electrolyte layer contacts the conductive portion 203 covering the battery cell below, participating in the construction of the electrochemical reaction interface; simultaneously, its conductive layer 304 can contact the positive electrode assembly in other battery cells to achieve electrical connection. Figure 9As shown, the integrated configuration of the battery module also includes an expanded capacity cell. The expanded capacity cell includes at least one third positive electrode assembly 400 stacked together. The third positive electrode assembly 400 includes a negative electrode portion 401 and a fourth solid electrolyte layer. The negative electrode portion 401 (such as a metal foil strip) is fixedly disposed on the conductive layer 304. After the negative electrode portion 401 is connected and bent along the stacking direction of the third positive electrode assembly 400, it contacts the fourth solid electrolyte layer in the corresponding third positive electrode assembly 400 to achieve electrical connection, thereby electrically connecting the independent cell and the expanded capacity cell in series or parallel.

[0063] like Figure 10 As shown, the structure of the third positive electrode component 400 is the same as that of the first positive electrode component 100, so it will not be described again here.

[0064] It should be noted that, as Figure 9 As shown, after the expanded capacity cell is installed on the battery cell, the positive electrode tabs in the third positive electrode assembly 400 are electrically connected to each other. This allows the second positive electrode assembly 300 to share the same negative electrode assembly 200 with all the first positive electrode assemblies 100 and the third positive electrode assembly 400. That is, different positive electrode assemblies 100 do not each have their own independent negative electrode structure, but achieve a unified negative electrode circuit by sharing the same negative electrode assembly 200. For example, when higher energy output is required, more third positive electrode assemblies 400 can be stacked and connected in parallel using the second positive electrode assembly 300, without the need to configure an independent negative electrode assembly and external busbar for each set of newly added positive electrode assemblies. This significantly reduces the amount of inactive materials used, simplifies the assembly process, and improves space utilization and energy density. In addition, since all positive electrode assemblies share a single negative electrode assembly 200, and only a single positive electrode tab and a single negative electrode tab 205 are ultimately led out as external output terminals, the entire battery structure is highly integrated.

[0065] The present invention also provides a method for preparing a battery cell, for use in the above-mentioned battery cell, specifically comprising the following steps:

[0066] S1. Fabrication of multiple first positive electrode components 100: First, cut the positive electrode current collector layer (e.g., aluminum foil) to form a rectangular structure with the same width as the conductive part 203 used later, reserving a portion of the area to extend as the first positive electrode tab 107. Coat, laminate, or cure a layer of positive electrode material (e.g., NCM ternary material or lithium iron phosphate) on both sides of the positive electrode current collector. Then, cover the outer surface of each positive electrode material with a dense solid electrolyte layer (e.g., sulfide or oxide electrolyte), forming a symmetrical multilayer sandwich structure (e.g., solid electrolyte layer - positive electrode material layer - positive electrode current collector layer - positive electrode material layer - solid electrolyte layer) from bottom to top. Figure 2(As shown). Subsequently, an insulating frame 106 (such as epoxy resin or polyimide) is printed on the periphery of the first positive electrode assembly 100, so that the insulating frame 106 completely covers the side of the first positive electrode assembly 100 (only the upper and lower surfaces are exposed), exposing only the first positive electrode tab 107 portion;

[0067] S2. Fabrication of the negative electrode assembly 200: Cut the negative electrode current collector layer 201 (including the negative electrode tab 205) and the negative electrode material layer 202 (carbon-based material, silicon-based material, lithium metal and alloys, etc.). The negative electrode material layer 202 is coated, laminated, or cured on one side surface of the negative electrode current collector layer 201. Cut metal foil to form a strip-shaped conductive portion 203 (the same width as the positive electrode current collector layer in the first positive electrode assembly 100). Use a laminating machine to precisely press the conductive portion 203 (metal foil) onto the opposite side surface of the negative electrode current collector layer 201 (e.g., ...). Figure 3 (as shown); Figure 11 As shown, the negative electrode current collector layer 201 (including the negative electrode tab 205) can be cut, and a metal foil can be cut to form a strip-shaped conductive part 203 (with the same width as the positive electrode current collector layer in the first positive electrode assembly 100). The conductive part 203 (metal foil) can be precisely pressed onto the negative electrode current collector layer 201 using a stacking machine. The conductive part 203 also has the function of negative electrode electrochemical function, thereby integrating the function of negative electrode material layer 202.

[0068] S3. Place the negative electrode component 200 from step S2 at the center of the stacking platform, and use a robotic arm or vacuum chuck to align and place a first positive electrode component 100 fabricated in step S1. Then, using a stacking machine, bend the conductive portion 203 within the negative electrode component 200 upwards to form a receiving space 204 (Z-shaped fold), so that it covers the top of the placed first positive electrode component 100 (e.g., ...). Figure 6 (As shown).

[0069] S4. Continue to bend the conductive part 203 upward to form a receiving space 204, and place the second first positive electrode assembly 100 in the receiving space 204, and then fold the conductive part 203 over it again using a stacking machine (e.g., Figure 7 (As shown). Repeat this process, sequentially stacking multiple first positive electrode components 100 according to the target capacity requirement.

[0070] S5. When the preset cell capacity is reached, the conductive part 203 is covered on the upper surface of the topmost first positive electrode component 100, and the conductive part 203 is cut off. The entire stacked structure is heated and pressurized (for example, held under high temperature and high pressure for a certain period of time) to ensure that the solid electrolyte between each layer is fully bonded to the positive and negative electrode materials, reduce the interface contact resistance to the set value, ensure stable and reliable ion conduction performance, and form an integrated "core package".

[0071] S6. Electrically connect the first positive electrode tabs 107 of all the first positive electrode components 100 stacked in the above steps. The resulting solid-state battery cell retains only one shared negative electrode tab 205 (from the negative electrode component 200) and one positive electrode tab.

[0072] If a battery pack is formed using only a single cell, then the cell can be sealed using a soft-pack aluminum-plastic film or other flexible encapsulation material. (A battery pack can be formed using a single cell or a battery module. If only a single cell is used, the single cell can be encapsulated independently.)

[0073] The present invention also provides a method for manufacturing a battery module for the above-mentioned battery module, specifically including the following steps:

[0074] S1. Fabricate a second positive electrode component 300 and multiple first positive electrode components 100 and third positive electrode components 400.

[0075] The preparation steps of the first positive electrode component 100 are as follows: First, the positive electrode current collector layer (such as aluminum foil) is cut to form a rectangular structure with the same width as the conductive part 203 used later, and a portion of the area is reserved to extend as the first positive electrode tab 107; a positive electrode material layer (such as NCM ternary material or lithium iron phosphate) is coated, laminated or cured on both sides of the positive electrode current collector; then a dense solid electrolyte layer (such as sulfide or oxide electrolyte) is covered on the outer surface of each positive electrode material, forming a symmetrical multilayer sandwich structure (such as solid electrolyte layer-positive electrode material layer-positive electrode current collector layer-positive electrode material layer-solid electrolyte layer) from bottom to top. Figure 2 (as shown); then, an insulating frame 106 (such as epoxy resin or polyimide) is printed on the periphery of the first positive electrode assembly 100, so that the insulating frame 106 completely covers the side of the first positive electrode assembly 100, exposing only the first positive electrode tab 107 portion.

[0076] The preparation steps of the second positive electrode component 300 are as follows: the positive electrode current collector layer (such as aluminum foil) is cut, and a portion of the area is reserved to extend as the second positive electrode tab 305. A positive electrode material layer (such as NCM ternary material or lithium iron phosphate) is coated, laminated or cured on one side surface of the positive electrode current collector layer. A solid electrolyte layer is coated, laminated or cured on the positive electrode material layer. A conductive layer 304 is pressed onto the other side of the positive electrode current collector layer. Subsequently, an insulating frame 106 (such as epoxy resin or polyimide) is printed on the four edges of the second positive electrode component 300, so that the insulating frame 106 completely covers the side of the second positive electrode component 300, exposing only the second positive electrode tab 305.

[0077] The structure of the third positive electrode component 400 is the same as that of the first positive electrode component 100. Therefore, the third positive electrode component 400 can be prepared using the same preparation steps as the first positive electrode component 100.

[0078] S2. Fabrication of the negative electrode assembly 200: Cut the negative electrode current collector layer 201 (including the negative electrode tab 205) and the negative electrode material layer 202 (carbon-based material, silicon-based material, lithium metal and alloys, etc.). The negative electrode material layer 202 is coated, laminated, or cured on one side surface of the negative electrode current collector layer 201. Cut metal foil to form a strip-shaped conductive portion 203 (the same width as the positive electrode current collector layer in the first positive electrode assembly 100). Use a laminating machine to precisely press the conductive portion 203 (metal foil) onto the opposite side surface of the negative electrode current collector layer 201 (e.g., ...). Figure 3 (as shown); Figure 11 As shown, the negative electrode current collector layer 201 (including the negative electrode tab 205) can be cut, and a metal foil can be cut to form a strip-shaped conductive part 203 (with the same width as the positive electrode current collector layer in the first positive electrode assembly 100). The conductive part 203 (metal foil) can be precisely pressed onto the negative electrode current collector layer 201 using a stacking machine. The conductive part 203 also has the function of negative electrode electrochemical function, thereby integrating the function of negative electrode material layer 202.

[0079] S3. Place the negative electrode component 200 from step S2 at the center of the stacking platform, and use a robotic arm or vacuum chuck to align and place a first positive electrode component 100 fabricated in step S1. Then, use a stacking machine to bend the conductive portion 203 on the negative electrode component 200 upwards to form a receiving space 204 (Z-shaped fold), so that it covers the top of the placed first positive electrode component 100 (e.g., ...). Figure 6 (As shown).

[0080] S4. Continue to bend the conductive part 203 upward to form a receiving space 204, and place the second first positive electrode assembly 100 in the receiving space 204, and then fold the conductive part 203 over it again using a stacking machine (e.g., Figure 7 (As shown). Repeat this process, sequentially stacking multiple first positive electrode components 100 according to the target capacity requirement.

[0081] S5. When the preset cell capacity is reached, the conductive part 203 is cut off and covered on the surface of the first positive electrode assembly 100.

[0082] S6. Place the second positive electrode assembly 300 on the topmost conductive part 203, cut a metal foil to form a strip-shaped negative electrode part 401 (the same width as the positive electrode current collector layer in the third positive electrode assembly 400), then press the negative electrode part 401 onto the second positive electrode assembly 300, bend the negative electrode part 401 upward to form a receiving space 204, and stack the third positive electrode assembly 400 within the receiving space 204 (e.g., ...).Figure 9 (As shown) Continue bending the negative electrode portion 401 to form a receiving space 204, then place the third positive electrode assembly 400 within the receiving space 204; keeping the negative electrode portion 401 continuous without cutting it off, repeat the above bending and stacking steps until the stacked electrode assembly reaches the preset battery capacity, then cut off the new negative electrode portion 401 (as shown). Figure 9 (As shown).

[0083] S7, such as Figure 9 As shown, the second positive electrode assembly stacked in the above steps is electrically connected to the positive electrode tabs of all the first positive electrode assemblies, and the positive electrode tabs of the third positive electrode assembly are electrically connected. The resulting solid-state battery module retains only one shared negative electrode tab 205 (from the negative electrode assembly 200) and one positive electrode tab.

[0084] Finally, the battery module can be sealed and encapsulated using a soft-pack aluminum-plastic film or other flexible packaging materials.

[0085] Of course, the solid-state battery fabrication method of the present invention is not limited to the above-described continuous Z-shaped stacking implementation. In other optional embodiments, a modular pre-integration process can also be adopted: that is, multiple first positive electrode components 100 are first stacked on independent workstations, and layer-by-layer electrical connections are achieved through flexible conductive conductive parts 203 to form a complete cell; subsequently, the pre-formed capacity-enhancing cell is used as an integral module and is aligned and placed on the prepared cell structure (a composite structure of the first positive electrode component 100 with the second positive electrode component 300 and the negative electrode component 200) by a robotic arm or automated transfer system for connection and assembly.

[0086] It should be noted that in this invention, the use of terms such as "first," "second," and "a" is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly defined. The terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal connection of two elements or the interaction between two elements, unless otherwise explicitly defined. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Furthermore, the technical solutions of the various embodiments of this invention can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0087] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that, include: Multiple first positive electrode components are stacked sequentially, each first positive electrode component including a solid electrolyte layer; A negative electrode assembly, comprising a conductive portion made of a flexible conductive material; The conductive portion is bent and extended along the stacking direction of the first positive electrode assembly to form a plurality of receiving spaces. Any two adjacent receiving spaces are separated from each other. One first positive electrode assembly is placed in each receiving space. The solid electrolyte layer in each first positive electrode assembly is in contact with at least one space wall of the receiving space to achieve electrical connection, so as to realize the electrical connection between one negative electrode assembly and multiple first positive electrode assemblies.

2. The battery cell according to claim 1, characterized in that, The first positive electrode assembly further includes a positive electrode current collector layer, which is stacked with the solid electrolyte layer. A portion of the positive electrode current collector layer extends outward to form a first positive electrode tab, and the first positive electrode tabs on all the first positive electrode assemblies are electrically connected to each other.

3. A battery cell according to claim 1, characterized in that, Each of the first positive electrode components includes two solid electrolyte layers, both of which are connected to the conductive portion.

4. A battery cell according to claim 3, characterized in that, The first positive electrode assembly includes a first solid electrolyte layer, a first positive electrode material layer, a first positive electrode current collector layer, a second positive electrode material layer, and a second solid electrolyte layer stacked sequentially, with a portion of the first positive electrode current collector layer extending outward to form a first positive electrode tab.

5. A battery cell according to claim 1, characterized in that, The negative electrode assembly further includes a negative electrode current collector layer and a negative electrode material layer. The conductive part and the negative electrode material layer are both disposed on the negative electrode current collector layer, and a portion of the negative electrode current collector layer extends outward to form a negative electrode tab.

6. A battery cell according to claim 2, characterized in that, Along the thickness direction of the first positive electrode assembly, an insulating frame is provided on the side of the first positive electrode assembly to prevent the conductive part from contacting other components in the first positive electrode assembly except for the solid electrolyte layer; a portion of the positive current collector layer in the first positive electrode assembly extends out of the insulating frame to form a first positive electrode tab.

7. A battery cell according to claim 1, characterized in that, It also includes a second positive electrode assembly, which has an insulating frame on its side and a conductive layer on its top. The second positive electrode assembly is stacked on top of the first positive electrode assembly and connected to the conductive part.

8. A battery cell according to claim 7, characterized in that, The second positive electrode assembly includes a second positive electrode current collector layer, a third positive electrode material layer and a third solid electrolyte layer stacked sequentially. The conductive layer is located on the second positive electrode current collector layer. The third solid electrolyte layer is connected to the conductive part to achieve electrical connection. A portion of the second positive electrode current collector layer extends outward to form a second positive electrode tab. The second positive electrode tab is electrically connected to all the first positive electrode tabs.

9. A battery module, characterized in that, The battery cell includes the battery cell as described in any one of claims 7-8 above, and further includes a capacity-enhancing battery cell, wherein the capacity-enhancing battery cell includes a negative electrode portion made of a flexible negative electrode material and at least one third positive electrode assembly stacked thereon, the third positive electrode assembly including a fourth solid electrolyte layer, the negative electrode portion being fixed on the conductive layer, and the negative electrode portion being connected and bent along the stacking direction of the third positive electrode assembly and then contacting the fourth fixed electrolyte layer in the corresponding third positive electrode assembly to achieve electrical connection.

10. A battery pack, characterized in that, Includes the battery cell as described in any one of claims 1-8 or the battery module as described in claim 9.

11. A method for preparing a battery cell, characterized in that, For use in the battery cell as described in any one of claims 1-6, the following steps are included: S1. Fabricate at least one first positive electrode component; S2. Fabricate a negative electrode assembly including a conductive part; S3. Place a fabricated first positive electrode component on the negative electrode component, and bend the conductive part to cover the first positive electrode component; S4. Place another first positive electrode assembly on the first positive electrode assembly, and continue to bend the conductive part so that it covers the other first positive electrode assembly; S5. Repeat step S4 until the preset battery capacity is reached, then cut off the conductive part. S6. Connect the positive electrode tabs of all the first positive electrode components stacked in the above steps.

12. A method for preparing a battery module, characterized in that, For use in the battery module as described in claim 9 above, the following steps are included: S1. Fabricate a second positive electrode assembly with a conductive layer, and at least one first positive electrode assembly, a third positive electrode assembly, and a negative electrode portion; S2. Fabricate a negative electrode assembly including a conductive part; S3. Place a fabricated first positive electrode component on the negative electrode component, and bend the conductive part to cover the first positive electrode component; S4. Place another first positive electrode assembly on top of the first positive electrode assembly, and continue to bend the conductive part so that it covers the other first positive electrode assembly. S5. Repeat S4 until the preset battery capacity is reached, and make the conductive part cover the topmost first positive electrode component, and cut off the conductive part. S6. Stack the second positive electrode assembly on the top conductive part in step S5 above. The third solid electrolyte layer in the second positive electrode assembly is connected to the conductive part. Place the negative electrode part on the conductive layer of the second positive electrode assembly. Place a fabricated third positive electrode assembly on the negative electrode part. Bend the negative electrode part so that it covers the third positive electrode assembly. Repeat the above-mentioned placement of the third positive electrode assembly and bending of the negative electrode part until the preset battery capacity is reached. Cut off the negative electrode part. S7. Connect the second positive electrode assembly stacked in the above steps to the positive electrode tabs of all the first positive electrode assemblies, and connect the positive electrode tabs of the third positive electrode assembly to the positive electrode assemblies.

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