Bipolar cell structure including integrally formed injection molded structure and bipolar battery

Abstract

The utility model relates to a bipolarity electric core structure and bipolarity battery including integrative injection molding structure, the bipolarity electric core structure includes the bipolarity pole piece of sequentially stacked between top plate and bottom plate, the sealing unit is arranged in the edge between adjacent pole piece in the bipolarity pole piece, the through -hole on the edge of the bipolarity pole piece and the current collector edge and the sealing unit of the through -hole is penetrated, integrative injection molding structure includes the shell for sealing the bipolarity electric core structure and the injection molding piece of the through -hole is penetrated, wherein, the injection molding piece limits the relative position deviation of pole piece and sealing unit, the bipolarity electric core structure of the utility model solves the problem such as traditional bipolarity battery interlayer displacement, stress concentration and electrolyte leakage.

Description

Technical Field

[0001] This utility model relates to a bipolar cell structure and a bipolar battery, which includes an integrally molded injection molding structure. Background Technology

[0002] Bipolar batteries, due to their alternating layered cell structure, still present numerous challenges in areas such as liquid injection, aging and venting, interlayer sealing, and structural stability. If the electrodes at the ends of a bipolar battery come into contact, a short circuit can occur. This is especially problematic when there are too many or too thick layers, leading to issues like liquid leakage, uneven stress causing displacement, and skewing in the stacked cell structure, thus reducing the product's yield.

[0003] Existing technology reports a mechanical clamping and sealing solution using metal bolts and insulating diaphragm rings to achieve sealing and compression of the battery cell. However, this bolt-based mechanical seal results in uneven stress distribution in the battery cell structure, with high stress at the clamping point and low stress in other parts of the electrode. During use, the structure undergoes longitudinal deformation or displacement (perpendicular to the electrode surface), leading to lithium plating and battery damage. Furthermore, the bolts require additional insulating sleeves for secure contact and to prevent displacement and short circuits in the current collector. Moreover, this solution is structurally complex and unstable, posing challenges to manufacturing and practical application.

[0004] Therefore, there is an urgent need to provide a new bipolar cell structure, including an integral injection-molded structure, to solve problems such as interlayer displacement, stress concentration, and electrolyte leakage in traditional bipolar batteries. Utility Model Content

[0005] The purpose of this utility model example embodiment is to solve the problems of interlayer displacement, stress concentration and electrolyte leakage in the prior art, and to provide a bipolar cell structure with uniform stress distribution, optimized sealing and simplified structure.

[0006] On the one hand, this utility model provides a bipolar battery cell structure, including:

[0007] - Bipolar electrodes stacked sequentially between the top and bottom plates;

[0008] - A sealing unit is disposed at the edge between adjacent electrodes in the bipolar electrode sheet;

[0009] - A perforation located at the edge of the bipolar electrode and extending through the current collector edge of the bipolar electrode and the sealing unit;

[0010] - A one-piece injection-molded structure, including a housing for sealing the bipolar cell structure and an injection-molded part penetrating the perforation;

[0011] The injection molded part restricts the relative positional offset of the electrode and the sealing unit.

[0012] In an embodiment of this utility model, the two ends of the injection molded part are integrally connected to the outer shell, and a stress-free fit is formed between it and the current collector and the sealing unit.

[0013] In an embodiment of this utility model, the injection molded part is fixed in the perforation by thermoplastic or thermosetting methods.

[0014] In the embodiments of this utility model, the injection molded part is not subjected to a fastening or clamping effect in the vertical direction.

[0015] In the embodiments of this utility model, the perforations of the current collector and the sealing unit form a stress-free fit with the injection molded part, and the planar projection of the perforation is a closed circular hole, a C-shaped hole with a groove on the edge side, or a concave hole.

[0016] In an embodiment of this invention, the bipolar cell structure further includes a reinforcing wire located within a perforation penetrating the edge of the bipolar electrode, the edge of the current collector, and the sealing unit. The reinforcing wire is selected from glass fiber insulated wire, fluoroplastic-coated insulated wire, aramid insulated wire, high-temperature PVC-coated wire, high-temperature nylon wire, ceramic fiber wire, or combinations thereof.

[0017] In an embodiment of this utility model, the sealing unit is located between adjacent current collectors and abuts against the positive electrode material, the negative electrode material and / or the diaphragm.

[0018] In an embodiment of this utility model, the perforations and injection molded parts are distributed at least on two opposite sides of the bipolar battery cell structure, and there are at least two injection molded parts on each side.

[0019] On the other hand, this utility model provides a bipolar battery, including the bipolar cell structure described in this utility model.

[0020] In this invention, the injection molded part can prevent lateral displacement and slippage of the stacked battery cell structure and misalignment of the electrode sheets. Furthermore, by using an integral molding method, the injection molded part does not require the clamping of the top and bottom plates commonly used in the prior art, thus avoiding the displacement or damage problems caused by uneven longitudinal stress resulting from the clamping structure in the prior art.

[0021] Furthermore, through integral molding, the injection-molded part is bonded or chemically cross-linked with the current collector of the electrode. This method of sealing the electrode / current collector is simple and easy to implement. Together with the sealing unit, it can prevent electrolyte leakage and electrode short circuits, and can also enhance the structural bonding force, improve interface stability, and avoid the problems of uneven stress and structural damage caused by pressure mechanical seals.

[0022] Finally, the injection molded part can be made of insulating material to avoid electrode short circuits and improve cell safety; the sealing unit is located between the upper and lower layers of the current collector to ensure the airtightness of the cell, prevent electrolyte leakage, and improve overall mechanical strength; the sealing unit abuts against the positive electrode material, negative electrode material and / or separator to further optimize the internal structure of the cell, reduce interface impedance, and improve electrochemical performance.

[0023] Other features and aspects will become clear from the following detailed description, accompanying drawings, and claims. Attached Figure Description

[0024] The present invention can be better understood by describing exemplary embodiments of the present invention in conjunction with the accompanying drawings, in which:

[0025] Figure 1 A schematic diagram of the bipolar battery cell structure in a specific embodiment of this utility model is shown.

[0026] Figure 2 This diagram shows an anatomical view of the bipolar battery cell structure in a specific embodiment of the present invention.

[0027] Figure 3 This diagram shows an anatomical view of the bipolar battery cell structure in a specific embodiment of the present invention.

[0028] Figure 4 This diagram shows a closed circular hole in the bipolar battery cell structure according to a specific embodiment of the present invention.

[0029] Figure 5 The diagram shows a C-shaped hole / concave hole in the bipolar cell structure of this utility model in a specific embodiment. Detailed Implementation

[0030] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the ordinary meaning as understood by one of ordinary skill in the art to which this utility model pertains.

[0031] In this document, when a numerical range such as 5-25 is given, this means at least 5 or not less than 5 and separately and independently not greater than or less than 25. In some embodiments, such a range may be independently defined as not less than 5 and separately and independently not greater than 25. Values ​​having such a range, such as 10, -15, or 10-20, also include the lower and upper limits of the range separately and independently in the same manner.

[0032] As used herein, unless otherwise specified, the terms “comprising” or “including” and similar words mean that the elements or objects preceding “comprising” or “including” encompass the elements or objects listed following “comprising” or “including” and their equivalents, and do not exclude other elements or objects.

[0033] In this invention, the distribution of the injection-molded parts is not particularly limited. In some specific embodiments, the injection-molded parts are distributed at least on two opposite sides of the bipolar cell structure, with at least two, three, or more injection-molded parts on each side. Those skilled in the art can configure the distribution according to the dimensions of the electrode sheets and engineering requirements. Figure 1 In some specific embodiments, the injection molded parts can be evenly distributed on the four sides of the edge of the bipolar sheet 11; in some specific embodiments, the injection molded parts 12 can be arranged symmetrically with a spacing of 5-10 mm.

[0034] Figure 2 The diagram shows an anatomical view of a bipolar cell structure according to one embodiment of the present invention, including a top plate 21, a bottom plate 22, a positive current collector 23 located below the top plate 21, a negative current collector 24 located above the bottom plate 22, a plurality of bipolar current collectors 20 stacked between the positive current collector 23 and the negative current collector 24, a positive electrode coating 25 on the bipolar current collectors 20 facing the positive current collector 23, a negative electrode coating 26 on the bipolar current collectors 20 facing the negative current collector 24, a sealing unit 28 located between the positive current collector 23 and the negative current collector 24, abutting against the positive electrode coating 25 and the negative electrode coating 26, and separating each bipolar current collector 20, and an injection molded part 27 penetrating the cover plate, the current collectors, and the sealing unit.

[0035] Figure 3 This diagram shows an anatomical view of a bipolar battery cell structure according to one embodiment of the present invention, including a top plate 21, a bottom plate 22, a positive current collector 23 located below the top plate 21, a negative current collector 24 located above the bottom plate 22, a plurality of bipolar electrode current collectors 20 stacked between the positive current collector 23 and the negative current collector 24, a positive electrode coating 25 on the bipolar electrode current collectors 20 facing the positive current collector 23, a negative electrode coating 26 on the bipolar electrode current collectors 20 facing the negative current collector 24, a sealing unit 28 located between the positive current collector 23 and the negative current collector 24, abutting against the positive electrode coating 25 and the negative electrode coating 26, and separating each bipolar electrode current collector 20, an injection molded part 27 penetrating the top plate, the bottom plate, the current collectors, and the sealing unit, and a reinforcing line 29.

[0036] In the bipolar cell structure of this invention, the outer shell can possess good mechanical properties, chemical stability, and insulation, and is typically selected from polycarbonate (PC), polyphenylene oxide (PPO), polyetheretherketone (PEEK), glass fiber reinforced plastic (GFRP), carbon fiber reinforced plastic (CFRP), alumina ceramic, zirconium oxide ceramic, etc. In the bipolar cell structure, the high strength and toughness of the outer shell ensure that it is not easily broken when subjected to external impact.

[0037] In the bipolar cell structure of this invention, the sealing unit must meet the requirements of chemical stability, mechanical compatibility, and interfacial compatibility. It is typically selected from ethylene propylene diene monomer (EPDM), nitrile butadiene rubber (NBR), hydrogenated nitrile butadiene rubber (HNBR), and fluororubber (FKM), such as polytetrafluoroethylene (PTFE), silicone rubber, polyurethane rubber (AU / EU), glass fiber reinforced epoxy resin, ceramic-metal composite layer, self-healing silicone rubber coating, graphene-modified polyurethane, aluminum-plastic film composite layer, and aerogel sealing felt. In some embodiments, the thickness of the sealing unit can be 0.1-0.3 mm, and the overlap width with the current collector edge can be ≥2 mm to ensure that the electrolyte cannot penetrate into the external environment.

[0038] In the bipolar cell structure of this invention, the injection-molded component serves to fix and stabilize the layers within the cell, and can be made of insulating thermoplastic or thermosetting resin materials. In some embodiments, the thermoplastic resin material is selected from polyoxymethylene (POM), polyetheretherketone (PEEK), polyamide (PA, nylon), polymethyl methacrylate (PMMA), polyphenylene sulfide (PPS), polycarbonate (PC), polysulfone (PSU), etc. In some embodiments, the thermosetting resin material is selected from epoxy resin, phenolic resin, unsaturated polyester resin (UPR), silicone resin, polyurethane resin (PU), furan resin, etc.

[0039] Figure 4 and Figure 5 The diagram shows a perforation of the injection-molded part. The perforation is located at the edge of the current collector and sealing unit. Its planar projection can be a closed circular hole 30, a C-shaped hole with a groove on the edge side, or a concave hole 40. Typically, the C-shaped hole allows the current collector to expand slightly in the radial direction, avoiding the accumulation of thermal expansion stress.

[0040] In embodiments of this invention, both ends of the injection-molded part are fixed only to the outer shell, forming a stress-free fit with the current collector and the sealing unit. In some embodiments, the gap between the injection-molded part and the current collector and sealing unit in the perforation is 0.02-0.05 mm, which can prevent the risk of short circuit caused by direct friction between the injection-molded part and the current collector. In some embodiments, the columnar surface of the injection-molded part penetrating the current collector and the sealing unit can be bonded to the sidewall of the perforation. This can also prevent mutual displacement between the current collector, the injection-molded part, and the sealing unit, and can further improve the insulation and sealing effect.

[0041] In this invention, the bipolar battery includes the bipolar cell structure.

[0042] Bipolar cell structure

[0043] The bipolar cell structure of this application includes a casing (optionally including a top plate and / or a bottom plate), bipolar electrodes, and an electrolyte (including liquid, semi-solid, and solid electrolytes). During battery charging and discharging, lithium ions repeatedly insert and extract between the positive and negative electrode sides. The electrolyte acts as a conductor for ions between the positive and negative electrode sides.

[0044] [Positive electrode side]

[0045] In the bipolar cell structure of this application, the positive electrode side includes a positive current collector and a positive electrode film layer (or positive electrode active material layer) disposed on at least one surface of the positive current collector and comprising a positive electrode active material. For example, the positive current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector. In the bipolar cell structure of this application, the positive current collector can be a metal foil or a composite current collector. For example, the metal foil can be aluminum foil, and the composite current collector can include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a polypropylene PP, polyethylene terephthalate PET, polybutylene terephthalate PBT, polystyrene PS, polyethylene PE and its copolymers, etc.).

[0046] In the bipolar cell structure of this application, the positive electrode active material (substance) can be any positive electrode active material known in the art for use in batteries. For example, the positive electrode active material may include one or more of the following: lithium phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811) and lithium nickel cobalt aluminum oxides (such as LiNi) 0.85 Co 0.15 Al 0.05 One or more of lithium iron phosphates (O2) and their modified compounds. Examples of lithium-containing phosphates with an olivine structure include, but are not limited to, lithium iron phosphate (such as LiFePO4 (LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites. In embodiments of this application, the second and third positive electrode active materials may be the same or different, and are selected from at least one of lithium iron phosphate (LFP), lithium manganese oxide (LMO), lithium nickel cobalt manganese oxide (NCM), lithium cobalt oxide (LCO), and lithium nickel cobalt aluminum oxide (NCA).

[0047] In some embodiments, the positive electrode film layer may optionally include a binder. Non-limiting examples of binders that can be used in the positive electrode film layer may include one or more of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins. In embodiments of this application, the first positive electrode active material layer and / or the second positive electrode active material layer each independently contain a binder selected from polyvinylidene fluoride, polyacrylic acid, polytetrafluoroethylene, polyimide, and combinations thereof.

[0048] In some embodiments, the positive electrode film layer may optionally include a conductive agent. Examples of conductive agents used for the positive electrode film layer may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In embodiments of this application, the first positive electrode active material layer and / or the second positive electrode active material layer each independently contain a conductive agent composed of graphite, carbon black, acetylene black, graphene, carbon nanotubes, and combinations thereof.

[0049] In one embodiment of this application, the positive electrode can be prepared by dispersing the above-mentioned components for preparing the positive electrode, such as positive electrode active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a uniform positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and obtaining the positive electrode side after drying, cold pressing and other processes.

[0050] [Negative electrode side]

[0051] In the bipolar cell structure of this application, the negative electrode side does not exclude additional functional layers besides the negative electrode substrate layer. For example, in some embodiments, the negative electrode side of this application may also include a conductive undercoating layer (e.g., composed of a conductive agent and an adhesive) sandwiched between the negative electrode current collector and the negative electrode substrate layer and disposed on the surface of the negative electrode current collector. In other embodiments, the negative electrode side of this application may also include a protective covering layer covering the surface of the second negative electrode film layer.

[0052] In the bipolar cell structure of this application, the negative electrode current collector can be a metal foil or a composite current collector. For example, the metal foil can be a copper foil, silver foil, iron foil, or an alloy of the above metals. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. It can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material base layer (such as a base layer made of polypropylene PP, polyethylene terephthalate PET, polybutylene terephthalate PBT, polystyrene PS, polyethylene PE and its copolymers, etc.).

[0053] [Electrolytes]

[0054] The electrolyte acts as a conductor of ions between the positive and negative electrode sides. The electrolyte can be selected from at least one of solid electrolytes, semi-solid electrolytes, and liquid electrolytes. In one embodiment of this application, the electrolyte may optionally contain additives. For example, additives may include one or more of the following: negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature performance, additives that improve battery low-temperature performance, etc.

[0055] [Isolation membrane]

[0056] In one embodiment of this application, the battery further includes a separator membrane that separates the anode side from the cathode side of the battery, providing selective permeability or blocking for substances of different types, sizes, and charges within the system. For example, the separator membrane can insulate against electrons, physically isolate the positive and negative electrodes of the battery, prevent internal short circuits, and form an electric field in a certain direction, while allowing ions in the battery to pass through the separator membrane and move between the positive and negative electrodes. In one embodiment of this application, the material used to prepare the separator membrane may include one or more of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator membrane can be a single-layer film or a multilayer composite film. When the separator membrane is a multilayer composite film, the materials of each layer can be the same or different. In embodiments of this application, the separator membrane is selected from polyolefin separator membranes, polyester separator membranes, polyimide separator membranes, polyamide separator membranes, and cellulose separator membranes.

[0057] In one embodiment of this application, bipolar electrodes and separators can be fabricated into electrode assemblies / bare cells using a winding process or a stacking process.

[0058] In one embodiment of this application, the battery may include an outer packaging that can be used to encapsulate the aforementioned electrode components and electrolyte. In some embodiments, the outer packaging of the battery may be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. In other embodiments, the outer packaging of the battery may be a soft pack, such as a pouch. The material of the soft pack may be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0059] The battery of this application can be cylindrical, square, or any other arbitrary shape. The outer packaging may include a shell and a cover plate. The shell may include a base plate and side plates connected to the base plate, the base plate and side plates enclosing a receiving cavity. The shell has an opening communicating with the receiving cavity, and the cover plate can be placed over the opening to close the receiving cavity. Bipolar electrodes and a separator can be formed into electrode assemblies using a winding or stacking process. These electrode assemblies are encapsulated within the receiving cavity, and the electrolyte is immersed in the electrode assemblies. The battery may contain one or more electrode assemblies.

[0060] In one embodiment of this application, several batteries can be assembled together to form a battery module, which contains two or more batteries, the specific number depending on the application of the battery module and the parameters of the individual battery module.

[0061] In a battery module, multiple batteries can be arranged sequentially along the length of the module. Alternatively, they can be arranged in any other manner. Furthermore, the batteries can be secured with fasteners. Optionally, the battery module may also include a housing with a receiving space in which the batteries are housed.

[0062] In one embodiment of this application, two or more of the above-described battery modules can be assembled into a battery pack. The number of battery modules contained in the battery pack depends on the application of the battery pack and the parameters of individual battery modules. The battery pack may include a battery box and multiple battery modules disposed within the battery box. The battery box includes an upper box and a lower box, the upper box being able to cover and fit snugly onto the lower box to form a closed space for accommodating the battery modules. Two or more battery modules can be arranged in the battery box in a desired manner.

[0063] In one embodiment of this application, the example battery pack may include a battery box and multiple battery modules disposed within the battery box. The battery box includes an upper box and a lower box, the upper box covering the lower box and forming a closed space for accommodating the battery modules. The multiple battery modules can be arranged in any manner within the battery box.

[0064] Electrical appliances

[0065] In one embodiment of this application, the electrical device includes at least one of the bipolar cell structure, battery module, or battery pack described in this application. The battery, battery module, or battery pack can be used as a power source for the electrical device or as an energy storage unit for the electrical device. The electrical device includes, but is not limited to, mobile digital devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, and energy storage systems.

[0066] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can be powered by a battery.

[0067] In the following text, the effects of batteries manufactured according to the embodiments of this application on the performance of electrochemical devices are characterized based on specific embodiments. However, it should be noted that the scope of protection of this application is defined by the claims and is not limited to the specific embodiments described above.

[0068] Example

[0069] Example 1: Electrode stacking followed by injection molding

[0070] 1. Preparation of bipolar electrodes

[0071] (1) Provide a bipolar electrode sheet coated with positive electrode material and negative electrode material, with a metal current collector layer (such as stainless steel layer) in the center of the electrode sheet, and positive electrode active material or negative electrode active material coated in the central area of ​​the upper and lower layers respectively; forming a sealing unit in the non-active coating area at the edge of the upper and lower layers of the current collector.

[0072] (2) Perforated prefabrication:

[0073] Eight sets of C-shaped holes are uniformly and precisely drilled on the edge of the current collector and sealing unit (elastic sealing ring), with the hole diameter matching the injection molded part.

[0074] 2. Electrode stacking

[0075] Twenty layers of prefabricated perforated electrode sheets are stacked onto a platform with positioning pins, with the perforations and pins corresponding one-to-one.

[0076] 3. One-piece injection molded structure:

[0077] The injection molding structure is made of PPS (reinforced polyphenylene sulfide). The injection molded part is integrally molded onto the shell and inserted into the perforation to form an integral injection molded part structure.

[0078] 4. Casing Installation

[0079] The cell is packaged without applying vertical clamping, the casing is sealed, and a lateral support is formed for the internal stacked cells.

[0080] Example 2: After pre-embedding the reinforcing wires and stacking the electrode sheets, the injection molded part is then injected.

[0081] 1. Preparation of bipolar electrodes

[0082] (1) Provide a bipolar electrode sheet coated with positive electrode material and negative electrode material, with a metal current collector layer (such as stainless steel layer) in the center of the electrode sheet, and positive electrode active material or negative electrode active material coated in the central area of ​​the upper and lower layers respectively; forming a sealing unit in the non-active coating area at the edge of the upper and lower layers of the current collector.

[0083] (2) Perforated prefabrication:

[0084] Eight sets of C-shaped holes are uniformly and precisely drilled on the edge of the current collector and sealing unit (elastic sealing ring), with the hole diameter matching the injection molded part.

[0085] 2. Electrode stacking

[0086] Twenty layers of prefabricated perforated electrode sheets are stacked onto a platform with locating pins, with each perforation and pin corresponding to the other.

[0087] 3. Reinforcing line runs through.

[0088] The reinforcing wire is threaded through the perforations of the stacked electrode sheets to provide initial stabilization and reinforcement.

[0089] 4. One-piece injection molded structure:

[0090] The injection molding structure is made of PPS (reinforced polyphenylene sulfide). The injection molded part is integrally molded onto the shell and inserted into the perforation to form an integral injection molded part structure.

[0091] 5. Housing installation

[0092] The cell is packaged without applying vertical clamping, the casing is sealed, and a lateral support is formed for the internal stacked cells.

[0093] Comparative Example 1

[0094] 1. Electrode stacking: 20 layers of bipolar electrodes are stacked in sequence, with a sealing ring sandwiched between the edges of the electrodes to form the core component of the battery cell.

[0095] 2. Casing installation: Cover the top and bottom of the battery cell with the metal top plate and bottom plate respectively.

[0096] 3. External clamping with bolts: At least 8 sets of metal bolts and nuts are installed around the cell, passing through the corner areas of the top and bottom plates, and evenly distributed around the cell.

[0097] 4. Apply mechanical pressure: Use a torque wrench to tighten the bolts in sequence to compress the battery cell in the vertical direction, so as to create contact pressure between the electrode and the sealing ring.

[0098] 5. Cell packaging: External coating or encapsulation to form basic airtightness.

[0099] Test Example 1

[0100] 1. Measure the stress distribution

[0101] Table 1:

[0102]

[0103] The influence of the fit between the injection molded part and the electrode sheet

[0104] Both Examples 1 and 2 use PPS injection molded parts (high thermal stability) and electrode perforations for integral molding to ensure electrode alignment during stacking. Example 2 further pre-sets reinforcing lines, while Comparative Example 1 has no through-type limiting and is only constrained by external bolts, resulting in a significantly higher interlayer misalignment rate (0.5-1.0 mm). Because Example 2 first pre-sets reinforcing lines to fix the injection molded parts before integral injection molding, the alignment accuracy is slightly better than Example 1 (misalignment rate < 0.1 mm (Example 2) - misalignment rate < 0.2 mm (Example 1)).

[0105] Correlation between stress distribution and sealing effect

[0106] The stress distribution uniformity of Examples 1 and 2 is far superior to that of Comparative Example 1: the stress range of Examples 1 and 2 is concentrated at 5-9 MPa, with a standard deviation of < 2 MPa, indicating that the stress is uniformly transmitted to each electrode layer through the injection molded part and / or reinforcing lines; while the stress of Comparative Example 1 is concentrated near the bolts (15-20 MPa), with the stress in the central area being only 2-3 MPa and a standard deviation of 6.8 MPa, resulting in uneven stress on the sealing unit. Meanwhile, due to the sturdiness of the reinforcing lines on the sides, Example 2 exhibits stronger lateral bearing capacity.

[0107] The sealing effect directly reflects the stress uniformity.

[0108] Example 1: Slightly higher (0.8 × 10⁻⁶) -8 The leakage rate (Pa・m³ / s) in Example 2 (0.5×10) -8 (Pa・m³ / s), while in Comparative Example 1, due to local underpressure in the sealing unit, the leakage rate reached 4.5×10⁻⁶. -8 Pa・m³ / s is 5-9 times that of the example.

[0109] In summary, Examples 1 and 2 significantly improve the stress uniformity, sealing effect, and structural stability of bipolar cells, which are superior to traditional external bolt clamping solutions. Among them, Example 1 is superior in overall performance.

[0110] Test Example 2

[0111] Destructive test: After applying a certain pressure, no rupture occurred, and there was no leakage or short circuit.

[0112] 1. Twenty sets of the novel battery cell structure and twenty sets of comparative samples using traditional bolt clamping were prepared, and the following destructive tests were performed:

[0113] 2. Vertical pressure test (equivalent to 20 kg / cm²)

[0114] 3. Thermal cycling test (-20℃~60℃, 10 cycles)

[0115] 4. Mechanical drop test (drop from a height of 1 meter)

[0116] Table 2: Comparison of Vertical Pressure Test Structures

[0117]

[0118] Table 3: Comparison of Thermal Cycling Test Results

[0119]

[0120] Table 4: Comparison of Mechanical Drop Test Results

[0121]

[0122] Although the present invention has been described in conjunction with specific embodiments, those skilled in the art will understand that many modifications and variations can be made to the present invention. Therefore, it is to be appreciated that the claims are intended to cover all such modifications and variations that are true to the concept and scope of the present invention.

Claims

1. A bipolar battery cell structure comprising an integrally molded injection-molded structure, characterized in that, The bipolar cell structure includes: - Bipolar electrodes stacked sequentially between the top and bottom plates; - A sealing unit is disposed at the edge between adjacent electrodes in the bipolar electrode sheet; - A perforation located at the edge of the bipolar electrode and extending through the current collector edge of the bipolar electrode and the sealing unit; - A one-piece injection-molded structure, including a housing for sealing the bipolar cell structure and an injection-molded part penetrating the perforation; The injection molded part restricts the relative positional offset of the bipolar electrode and the sealing unit.

2. The bipolar cell structure according to claim 1, characterized in that, The two ends of the injection molded part are integrally molded to the outer shell, and form a stress-free fit with the current collector and the sealing unit.

3. The bipolar cell structure according to claim 1, characterized in that, The injection molded part is fixed in the perforation by thermoplastic or thermosetting methods.

4. The bipolar cell structure according to claim 1, characterized in that, The injection molded part is not subjected to any fastening or clamping in the vertical direction.

5. The bipolar cell structure according to claim 1, characterized in that, The bipolar cell structure also includes reinforcing wires located within perforations that penetrate the edges of the bipolar electrode, the current collector, and the sealing unit.

6. The bipolar cell structure according to claim 1, characterized in that, The perforations of the current collector and sealing unit form a stress-free fit with the injection molded part. The planar projection of the perforation is a closed circular hole, a C-shaped hole with a groove on the edge side, or a concave hole.

7. The bipolar cell structure according to claim 1, characterized in that, The sealing unit is located between adjacent current collectors and abuts against the positive electrode material, the negative electrode material and / or the separator.

8. The bipolar cell structure according to claim 1, characterized in that, The perforations and injection molded parts are distributed on at least two opposite sides of the bipolar cell structure, and there are at least two injection molded parts on each side.

9. A bipolar battery, characterized in that, The bipolar battery comprises the bipolar cell structure according to any one of claims 1 to 8.

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