Battery cell assembly and battery box

Abstract

The application provides an electric core assembly and a battery box. The electric core assembly comprises a positive electrode sheet, the positive electrode sheet comprising a positive electrode body and a positive electrode lug connected electrically; a negative electrode sheet, the negative electrode sheet being located at least one side of the positive electrode sheet; a diaphragm, the diaphragm being located between adjacent positive electrode sheets and negative electrode sheets; an insulating layer, the insulating layer being located between the positive electrode lug and the positive electrode body; at least part of the insulating layer being arranged on opposite sides of the positive electrode body, and another part of the insulating layer being arranged on opposite sides of the positive electrode lug. The application effectively prevents the diaphragm from being pierced and short-circuited due to negative electrode burrs, beads and the like, thereby significantly improving the production yield and safety performance of the electric core.

Description

Technical Field

[0001] This application relates to a battery cell assembly and a battery box, belonging to the field of new energy battery technology. Background Technology

[0002] Lithium-ion batteries have high energy density per unit volume / mass, no memory effect, low internal resistance, low self-discharge, and long cycle life, and are widely used in many industries.

[0003] In conceiving and implementing this application, the applicant discovered at least the following problems: A battery cell typically includes a positive electrode, a negative electrode, and a separator between the positive and negative electrodes. During the slitting or fabrication process, burrs, molten metal beads, or foreign objects may be generated on the edges of the negative electrode. When the battery cell is subjected to external pressure or internal gas expansion, these sharp defects can easily puncture the separator. Once the separator is punctured, the edge of the negative electrode (usually a metal foil substrate) or the burrs will directly contact the active material on the positive electrode, forming a conductive path. This can lead to an internal short circuit within the battery cell, causing serious safety problems such as self-discharge, overheating, and even thermal runaway.

[0004] The preceding description is intended to provide general background information and does not necessarily constitute prior art. Utility Model Content

[0005] This application provides a battery cell assembly and battery box that effectively prevents short circuits caused by separator puncture due to negative electrode burrs, molten beads, etc., thereby significantly improving the cell manufacturing yield and safety performance.

[0006] This application provides a battery cell assembly, including:

[0007] The positive electrode plate includes an electrically connected positive electrode body and a positive electrode tab;

[0008] The negative electrode is located on at least one side of the positive electrode;

[0009] A separator is located between adjacent positive and negative electrode plates;

[0010] An insulating layer is located between the positive electrode tab and the positive electrode body; at least a portion of the insulating layer is located on opposite sides of the positive electrode body, and another portion of the insulating layer is located on opposite sides of the positive electrode tab.

[0011] The beneficial effects of this application are: by setting the insulation layer in sections on the opposite sides of the positive electrode body and the positive electrode tab, a three-dimensional insulation barrier covering the electrode stacking area and the electrode tab transition area is constructed, which solves the short circuit hazards caused by various reasons such as diaphragm shrinkage, burr puncture, assembly misalignment or vibration stress throughout the entire life cycle from manufacturing to use, and effectively prevents diaphragm puncture short circuits caused by negative electrode burrs, foreign objects, molten beads, etc., thereby significantly improving the cell manufacturing yield and safety performance.

[0012] In some optional embodiments, the positive electrode body includes a positive electrode current collector and positive electrode active material layers respectively disposed on opposite sides of the positive electrode current collector;

[0013] At least part of the insulating layer is disposed on opposite sides of the positive current collector and covers the negative electrode sheet.

[0014] It should be noted that by placing the insulating layer on both sides of the positive current collector and covering the opposite negative electrode sheet, a targeted "firewall" is formed. Even if burrs, molten beads, or foreign objects on the edge of the negative electrode pierce the separator, they will first come into contact with the robust insulating layer and will not be able to conduct electricity with the positive current collector or active material, thus effectively avoiding internal short circuits and significantly improving the cell's manufacturing yield and safety reliability.

[0015] In some alternative implementations, the height of at least a portion of the insulating layer covering the negative electrode is between 1 mm and 2 mm along the height direction of the positive electrode.

[0016] It should be noted that this height design completely covers the edge area of ​​adjacent negative electrode sheets. When there are burrs or molten beads on the edge of the negative electrode sheet due to processing, even if they pierce the separator, they will be blocked by the insulating layer and cannot come into contact with the positive current collector, thus preventing a short circuit.

[0017] In some alternative implementations, the battery cell assembly further includes a positive electrode connector, with a first end of the positive electrode tab electrically connected to the positive electrode body and a second end of the positive electrode tab electrically connected to the positive electrode connector.

[0018] Another part of the insulating layer is located on both sides of the first end of the positive electrode tab.

[0019] It should be noted that the first end of the positive electrode tab is a stress concentration point in mechanical terms. During battery charging, discharging, expansion, contraction, and vibration, the deformation and stress at this point are the greatest, which can easily lead to cracking and peeling of the traditional insulating coating. A specially designed insulating layer at this point can effectively prevent short circuits caused by insulation failure.

[0020] In some alternative implementations, the insulating layer is a soft-hard composite insulating layer.

[0021] It should be noted that a single material insulation layer cannot meet all the requirements at the same time. Therefore, a soft-hard composite insulation material can not only provide sufficient mechanical strength to resist compression and puncture, but also adapt to the deformation caused by the bending of the tab and the expansion of the electrode without cracking.

[0022] In some alternative embodiments, the insulating layer includes a first insulator layer and a second insulator layer;

[0023] The first insulator layer is located on opposite sides of the positive electrode body, and the second insulator layer is located on opposite sides of the positive electrode lug.

[0024] The first insulator layer is a rigid insulation layer, and the second insulator layer is a soft insulation layer.

[0025] It should be noted that the composite structure, in which a rigid insulation layer is located on the positive electrode body side and a soft insulation layer is located on the positive electrode tab side, makes the best use of the materials. The rigid layer provides excellent resistance to compression and puncture in the main electrode area; while the soft layer in the tab root area can adapt to bending and vibration, preventing the insulation layer from cracking and falling off, thus ensuring the long-term effectiveness of insulation protection.

[0026] In some alternative embodiments, the height of the first insulator layer is between 2 mm and 3 mm along the height direction of the positive electrode sheet; and / or,

[0027] Along the thickness direction of the positive electrode sheet, the thickness of the first insulator layer is between 60μm and 100μm.

[0028] It should be noted that the design of these parameters gives it excellent resistance to compression and puncture, providing robust, fortress-like protection for the electrode stacking area.

[0029] In some alternative embodiments, the height of the second insulator layer is between 3 mm and 7 mm along the height direction of the positive electrode sheet; and / or,

[0030] Along the thickness direction of the positive electrode sheet, the thickness of the second insulator layer is between 20μm and 50μm.

[0031] It should be noted that the larger height range is to cover the heat-affected zone during tab bending and welding. The smaller thickness ensures its flexibility and prevents it from becoming too thick and affecting bending performance.

[0032] In some alternative embodiments, there is a mutually soluble region between the first insulator layer and the second insulator layer;

[0033] Along the height direction of the positive electrode, the height of the miscible region is between 0.1 mm and 0.5 mm.

[0034] It should be noted that the interfacial region between the first and second insulator layers eliminates the clear interface between different materials, forming a strong bond with a gradient transition. This effectively prevents interlayer delamination and ensures the structural integrity and insulation continuity of the entire insulation system under complex working conditions.

[0035] In addition, this application also provides a battery box, including a box body and the aforementioned battery cell assembly, wherein the battery cell assembly is disposed inside the box body.

[0036] The battery cell assembly and battery box provided in this application include a box body and the aforementioned battery cell assembly, with the battery cell assembly disposed within the box body; the battery cell assembly includes a positive electrode plate, which includes an electrically connected positive electrode body and a positive electrode tab; a negative electrode plate, which is located on at least one side of the positive electrode plate; a separator, which is located between adjacent positive and negative electrode plates; and an insulating layer, which is located between the positive electrode tab and the positive electrode body; at least a portion of the insulating layer is disposed on opposite sides of the positive electrode body, and another portion of the insulating layer is disposed on opposite sides of the positive electrode tab.

[0037] By partitioning the insulation layer on both sides of the positive electrode body and the positive electrode tab, a three-dimensional insulation barrier covering the electrode stacking area and the electrode tab transition area is constructed. This solves the short circuit hazards caused by various reasons such as diaphragm shrinkage, burr puncture, assembly misalignment or vibration stress throughout the entire life cycle from manufacturing to use. It effectively prevents diaphragm puncture short circuits caused by negative electrode burrs, foreign objects, molten beads, etc., thereby significantly improving the cell manufacturing yield and safety performance. Attached Figure Description

[0038] The above and other objects, features, and advantages of embodiments of this application will become more readily understood through the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application will be described by way of example and non-limitation, wherein:

[0039] Figure 1 This is a schematic diagram of the structure of a battery cell assembly according to an embodiment of this application;

[0040] Figure 2 This is a schematic diagram of the structure of the positive electrode in a battery cell assembly according to an embodiment of this application;

[0041] Figure 3 This is a schematic diagram of another battery cell assembly according to an embodiment of this application;

[0042] Figure 4 This is a schematic diagram of the positive electrode plate in another battery cell assembly according to an embodiment of this application;

[0043] Figure 5 This is a schematic diagram of the positive electrode sheet after laser cutting in another battery cell assembly according to an embodiment of this application;

[0044] Figure 6 for Figure 5 A magnified view of a portion of point I in the middle.

[0045] Figure label:

[0046] 100-Battery Cell Assembly;

[0047] 110-Positive electrode plate;

[0048] 111 - Positive electrode body;

[0049] 112-Positive electrode ear;

[0050] 120-Negative electrode;

[0051] 130 - Diaphragm;

[0052] 140 - Insulation layer;

[0053] 141 - First insulator layer;

[0054] 142 - Second insulator layer;

[0055] 150 - Positive electrode connector. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. All other obtained embodiments are within the scope of protection of this application. In the absence of conflict, the following embodiments and features can be combined with each other.

[0057] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0058] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0059] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0060] In conceiving and implementing this application, the applicant discovered at least the following problems: A battery cell typically includes a positive electrode, a negative electrode, and a separator between the positive and negative electrodes. During the slitting or fabrication process, burrs, molten metal beads, or foreign objects may be generated on the edges of the negative electrode. When the battery cell is subjected to external pressure or internal gas expansion, these sharp defects can easily puncture the separator. Once the separator is punctured, the edge of the negative electrode (usually a metal foil substrate) or the burrs will directly contact the active material on the positive electrode, forming a conductive path. This can lead to an internal short circuit within the battery cell, causing serious safety problems such as self-discharge, overheating, and even thermal runaway.

[0061] The battery cell assembly proposed in this application constructs a three-dimensional insulating barrier covering the electrode stacking area and the electrode transition area by dividing the insulation layer into sections on opposite sides of the positive electrode body and the positive electrode tab. This solves the short circuit hazards caused by various reasons such as diaphragm shrinkage, burr puncture, assembly misalignment or vibration stress throughout the entire life cycle from manufacturing to use. It effectively prevents diaphragm puncture short circuits caused by negative electrode burrs, foreign objects, molten beads, etc., thereby significantly improving the manufacturing yield and safety performance of the battery cell.

[0062] The battery cell assembly provided in this application will be described in detail below with reference to specific embodiments.

[0063] Figure 1 This is a schematic diagram of the structure of a battery cell assembly according to an embodiment of this application. Figure 2 This is a schematic diagram of the structure of the positive electrode in a battery cell assembly according to an embodiment of this application. Figure 3 This is a schematic diagram of another battery cell assembly according to an embodiment of this application. Figure 4 This is a schematic diagram of the positive electrode plate in another battery cell assembly according to an embodiment of this application. Figure 5 This is a schematic diagram of the positive electrode sheet after laser cutting in another battery cell assembly according to an embodiment of this application. Figure 6 for Figure 5 A magnified view of a portion of point I in the middle.

[0064] like Figures 1 to 6As shown in the figure, this application provides a battery cell assembly 100, comprising:

[0065] Positive electrode 110, the positive electrode 110 includes a positive electrode body 111 and a positive electrode tab 112 that are electrically connected;

[0066] The negative electrode 120 is located on at least one side of the positive electrode 110;

[0067] A separator 130 is located between adjacent positive electrode plates 110 and negative electrode plates 120;

[0068] An insulating layer 140 is located between the positive electrode tab 112 and the positive electrode body 111; at least a portion of the insulating layer 140 is disposed on opposite sides of the positive electrode body 111, and another portion of the insulating layer 140 is disposed on opposite sides of the positive electrode tab 112.

[0069] It should be noted that the battery cell assembly 100 is formed by stacking or winding a positive electrode 110, a negative electrode 120, and a separator 130. The positive electrode 110 includes a positive electrode body 111 coated with an active material and a positive electrode tab 112 made of aluminum. An insulating layer 140 is provided in the connection transition area between the positive electrode body 111 and the positive electrode tab 112.

[0070] Part of the insulating layer 140 covers the upper and lower surface edges of the positive electrode body 111 and extends towards the electrode tab; another part covers the upper and lower sides of the root of the positive electrode tab 112. This forms a complete insulation protection zone.

[0071] It not only protects the electrode stacking area (positive electrode body 111), which is most prone to short circuits, but also the electrode tab transition area, which has a complex structure and is susceptible to stress and vibration. It fundamentally solves the potential short circuit hazards caused by various reasons such as diaphragm 130 shrinkage, burr puncture, assembly misalignment, or long-term vibration during the manufacturing, assembly, and use of the battery cell.

[0072] Furthermore, by setting the insulating layer 140 to be "at least partially on both sides of the positive electrode body 111 and another part on both sides of the positive electrode tab 112", a continuous or segmented insulating barrier is formed, which significantly reduces the probability of internal short circuits, thereby improving the thermal stability and cycle life of the battery and reducing the risk of thermal runaway.

[0073] In some embodiments, the insulating layer 140 is formed by a coating process. A portion of the insulating layer 140 is disposed on the edges of both sides of the positive electrode body 111, specifically coated on the exposed portion of the positive electrode current collector. Another portion of the insulating layer 140 is disposed on opposite sides of the first end (i.e., the root) of the positive electrode tab 112. The insulating layer 140 here is made of a flexible adhesive material (such as polyvinylidene fluoride-hexafluoropropylene copolymer-based adhesive), which can withstand the stress caused by tab bending and vibration without cracking.

[0074] By setting the insulation layer 140 in sections on opposite sides of the positive electrode body 111 and the positive electrode tab 112, a three-dimensional insulation barrier covering the electrode stacking area and the electrode tab transition area is constructed. This solves the short circuit hazards caused by various reasons such as diaphragm 130 shrinkage, burr puncture, assembly misalignment or vibration stress throughout the entire life cycle from manufacturing to use. It effectively prevents short circuits caused by puncture of diaphragm 130 due to negative electrode burrs, foreign objects, molten beads, etc., thereby significantly improving the cell manufacturing yield and safety performance.

[0075] In some optional embodiments, the positive electrode body 111 includes a positive electrode current collector and positive electrode active material layers respectively disposed on opposite sides of the positive electrode current collector;

[0076] At least a portion of the insulating layer 140 is disposed on opposite sides of the positive current collector and covers the negative electrode sheet 120.

[0077] It should be noted that by placing the insulating layer 140 on both sides of the positive current collector and covering the opposite negative electrode sheet 120, a targeted "firewall" is formed. Even if burrs, molten beads, or foreign objects on the edge of the negative electrode pierce the separator 130, they will first come into contact with the robust insulating layer 140 and will not be able to conduct electricity with the positive current collector or active material, thereby effectively avoiding internal short circuits and significantly improving the cell's manufacturing yield and safety reliability.

[0078] Specifically, the location of the insulating layer 140 is defined as the edge of the "bare metal" current collector, which contains no active material. This is the most likely dangerous area where the positive and negative electrode plates 120 will come into direct contact. By placing the insulating layer 140 here, short circuits between the positive current collector and the opposite negative electrode plate 120 can be directly and effectively prevented.

[0079] Furthermore, even if the diaphragm 130 becomes locally thinner, damaged, or shrinks due to process or external force, the insulation layer 140 at this location can serve as a reliable backup line of defense to ensure insulation safety.

[0080] In some embodiments, the positive electrode body 111 is composed of a positive electrode current collector (such as aluminum foil) and positive electrode active material layers coated on both sides. The positive electrode tab 112 extends from one end of the positive electrode body 111, with its first end electrically connected to the positive electrode body 111 and its second end connected to the positive electrode connecting piece 150 by means of ultrasonic welding or the like.

[0081] It should be noted that the battery cell assembly 100 includes multiple battery cell bodies, which are the smallest charging and discharging units. Each battery cell has a positive electrode 110, a negative electrode 120, and a separator 130 disposed between them, and is formed by winding or stacking.

[0082] The positive electrode 110 includes a positive current collector and a positive active material layer, which can be one or two layers; that is, the positive active material layer is located on one side of the positive current collector, or the positive active material layer is located on opposite sides of the positive current collector.

[0083] For example, the positive current collector can be made of metal materials such as aluminum foil, nickel foil, or stainless steel, or a composite foil formed by combining metal and insulating materials.

[0084] For example, the positive electrode active material layer includes a positive electrode active material, a conductive agent, a binder, etc., and the positive electrode active material includes one or more lithium-containing positive electrode active materials such as lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate.

[0085] Similarly, the negative electrode 120 includes a negative electrode current collector and a negative electrode active material layer, which can be one or two layers; that is, the negative electrode active material layer is located on one side of the negative electrode current collector, or the negative electrode active material layer is located on opposite sides of the negative electrode current collector.

[0086] For example, the negative electrode current collector can be made of metal materials such as copper foil, aluminum foil, or stainless steel, or it can be a composite foil material formed by combining metal and insulating materials.

[0087] For example, the negative electrode active material layer includes a negative electrode active material, a conductive agent, a binder, etc., and the negative electrode active material includes one or more of the following: artificial graphite, natural graphite, silicon carbide, silicon oxide, lithium titanate, etc.

[0088] The tab serves as the current output terminal of the battery cell. The tab and the positive electrode 110 or the negative electrode 120 are connected as one piece or separately.

[0089] The separator 130 serves as an insulating layer 140 to prevent short circuits inside the cell assembly caused by the contact between the positive electrode 110 and the negative electrode 120. The separator 130 also serves as a semi-permeable layer to prevent larger molecules from passing through while allowing smaller charged ions to pass through.

[0090] In some alternative embodiments, the height of at least a portion of the insulating layer 140 covering the negative electrode 120 is between 1 mm and 2 mm along the height direction of the positive electrode 110.

[0091] It should be noted that this height design completely covers the edge area of ​​the adjacent negative electrode 120. When there are burrs or molten beads on the edge of the negative electrode 120 due to processing, even if they pierce the separator 130, they will be blocked by the insulating layer 140 and cannot contact the positive current collector, thereby preventing a short circuit.

[0092] Specifically, the lower limit of 1mm ensures the minimum effective insulation distance, which can reliably cover manufacturing tolerances and possible misalignment of electrode plates, guaranteeing a safety baseline.

[0093] The 2mm upper limit prevents the insulation layer from being too tall and excessively encroaching on the space of the active material inside the cell, thus avoiding a significant loss of energy density. This reflects a balance achieved between safety and energy density.

[0094] In some alternative embodiments, the battery cell assembly 100 further includes a positive electrode connector 150, with a first end of the positive electrode tab 112 electrically connected to the positive electrode body 111 and a second end of the positive electrode tab 112 electrically connected to the positive electrode connector 150.

[0095] Another portion of the insulating layer 140 is disposed on opposite sides of the first end of the positive electrode tab 112.

[0096] It should be noted that the first end of the positive electrode tab 112 is a stress concentration point in mechanical terms. During battery charging, discharging, expansion, contraction, and vibration, the deformation and stress at this point are the greatest, which can easily lead to cracking and peeling of the traditional insulating coating. An insulating layer 140 is specially set at this point to effectively prevent short circuits caused by insulation failure.

[0097] In addition, the insulation protection is naturally extended from the "electrode area" to the "ear area", ensuring that there are no weak points in the insulation throughout the current path.

[0098] like Figure 1 and Figure 2 As shown, in some optional embodiments, the insulating layer 140 is a soft-hard composite insulating layer 140.

[0099] It should be noted that a single-material insulation layer 140 cannot meet all the requirements at the same time. Therefore, a soft-hard composite insulation material can not only provide sufficient mechanical strength to resist compression and puncture, but also adapt to the deformation caused by the bending of the tab and the expansion of the electrode without cracking.

[0100] In some embodiments, the height of the insulating layer 140 is between 5mm and 10mm along the height direction of the positive electrode 110. This ensures that the insulating layer 140 simultaneously covers the bending area of ​​both the negative electrode and the positive electrode tab 112 on the tab side.

[0101] In some embodiments, to prevent the insulating layer 140 from being punctured by copper foil burrs, the thickness of the insulating layer 140 is between 30 μm and 100 μm along the thickness direction of the positive electrode 110.

[0102] In some embodiments, to ensure that the positive electrode active material, the separator 130, and the negative electrode active material are tightly bonded together, their thickness does not exceed the thickness of the positive electrode active material layer.

[0103] In some embodiments, the soft-hard composite insulating material is soft PI, hard alumina / boehmite, etc., which are mixed in a certain proportion and then mixed with PVDF / PMMA binder in NMP solvent to prepare a slurry, which is then coated.

[0104] like Figures 3 to 6 As shown, in some alternative embodiments, the insulating layer 140 includes a first insulator layer 141 and a second insulator layer 142.

[0105] The first insulator layer 141 is disposed on opposite sides of the positive electrode body 111, and the second insulator layer 142 is disposed on opposite sides of the positive electrode lug 112.

[0106] The first insulator layer 141 is a rigid insulation layer 140, and the second insulator layer 142 is a soft insulation layer 140.

[0107] It should be noted that the composite structure, in which a rigid insulating layer 140 is located on the positive electrode body 111 side and a soft insulating layer 140 is located on the positive electrode tab 112 side, makes the best use of the materials. The rigid layer provides excellent resistance to compression and puncture in the main electrode area; while the soft layer in the tab root area can adapt to bending and vibration, preventing the insulating layer 140 from cracking and falling off, thus ensuring the long-term effectiveness of insulation protection.

[0108] Specifically, in the positive electrode body 111 region (first insulator layer 141 - rigid), this region mainly bears the long-term expansion stress of the battery cell. Using a rigid insulation layer 140 can provide stable mechanical support, prevent the insulation layer 140 from being compacted and failing, and provide excellent resistance to compression and puncture.

[0109] The positive electrode tab 112 region (second insulator layer 142 - soft) requires bending and welding, and is subject to stress concentration. The use of soft insulation layer 140 ensures excellent flexibility and fatigue durability, maintaining insulation integrity under repeated deformation.

[0110] In some embodiments, the rigid insulating material of the first insulator layer 141 is alumina, boehmite, zirconium oxide, etc., which is mixed with PVDF / PMMA and other binders in a certain proportion in an NMP solution to prepare a slurry.

[0111] In some embodiments, the soft insulating material of the second insulator layer 142 is a polypropylene polymer material such as PI, which is mixed with PVDF / PMMA and NMP in a certain proportion to prepare a slurry.

[0112] In some alternative embodiments, the height of the first insulator layer 141 is between 2 mm and 3 mm along the height direction of the positive electrode 110; and / or,

[0113] Along the thickness direction of the positive electrode 110, the thickness of the first insulator layer 141 is between 60μm and 100μm.

[0114] It should be noted that the design of these parameters gives it excellent resistance to compression and puncture, providing robust, fortress-like protection for the electrode stacking area.

[0115] Specifically, the height of the first insulator layer 141 is 2mm-3mm, which facilitates meeting the process and yield requirements of the ceramic layer covering the negative electrode with a thickness of 0.5-2mm.

[0116] The thickness of the first insulator layer 141 is 60μm-100μm. To ensure that the positive electrode active material, the separator 130, and the negative electrode active material are tightly bonded together, the thickness of the first insulator layer 141 does not exceed the thickness of the positive electrode active material layer.

[0117] It should be noted that X represents the height direction of the positive electrode 110, and Y represents the thickness direction of the positive electrode 110.

[0118] In some alternative embodiments, the height of the second insulator layer 142 is between 3 mm and 7 mm along the height direction of the positive electrode 110; and / or,

[0119] Along the thickness direction of the positive electrode 110, the thickness of the second insulator layer 142 is between 20 μm and 50 μm.

[0120] It should be noted that the larger height range is to cover the heat-affected zone during tab bending and welding. The smaller thickness ensures its flexibility and prevents it from becoming too thick and affecting bending performance.

[0121] In some alternative embodiments, there is a mutually soluble region between the first insulator layer 141 and the second insulator layer 142;

[0122] Along the height direction of the positive electrode 110, the height of the intersoluble region is between 0.1mm and 0.5mm.

[0123] It should be noted that the interfacial region between the first insulator layer 141 and the second insulator layer 142 eliminates the clear interface between different materials, forming a strong bond with a gradient transition, effectively preventing interlayer peeling, and ensuring the structural integrity and insulation continuity of the entire insulation system under complex working conditions.

[0124] Furthermore, the mutual solubility region means that the two materials permeate and bond with each other at the interface, forming a gradient transition layer. This solves the problem of interfacial delamination caused by insufficient adhesion between different material layers. It also avoids weak points in insulation at the junction of soft and hard materials.

[0125] The battery cell assembly provided in this application includes a positive electrode sheet, which includes a positive electrode body and a positive electrode tab that are electrically connected; a negative electrode sheet, which is located on at least one side of the positive electrode sheet; a separator, which is located between adjacent positive and negative electrode sheets; and an insulating layer, which is located between the positive electrode tab and the positive electrode body; at least a portion of the insulating layer is disposed on opposite sides of the positive electrode body, and another portion of the insulating layer is disposed on opposite sides of the positive electrode tab.

[0126] By partitioning the insulation layer on both sides of the positive electrode body and the positive electrode tab, a three-dimensional insulation barrier covering the electrode stacking area and the electrode tab transition area is constructed. This solves the short circuit hazards caused by various reasons such as diaphragm shrinkage, burr puncture, assembly misalignment or vibration stress throughout the entire life cycle from manufacturing to use. It effectively prevents diaphragm puncture short circuits caused by negative electrode burrs, foreign objects, molten beads, etc., thereby significantly improving the cell manufacturing yield and safety performance.

[0127] In addition, this application embodiment also provides a battery box, including a box body and the above-mentioned battery cell assembly 100, wherein the battery cell assembly 100 is disposed in the box body.

[0128] It should be noted that the battery cell assembly 100 can be composed of multiple cells connected in series or in parallel to form a battery module. Due to the use of the aforementioned high-safety battery cell assembly 100, the battery box has higher reliability and a longer service life, making it particularly suitable for fields with extremely high safety requirements, such as electric vehicles and large-scale energy storage.

[0129] The housing has a receiving cavity, which is used to house the battery cell assembly 100. It is easy to understand that the receiving cavity is sealed to prevent side reactions from occurring in the internal system of the battery cell assembly 100, which would affect the performance of the battery cell.

[0130] For example, the size or shape of the receiving cavity is matched with the size and shape of the battery. Specifically, it can be adjusted according to the actual situation. This application embodiment does not impose too many limitations here.

[0131] In this embodiment, the battery cell assembly 100 can be configured as a rectangular structure. The battery cell assembly 100 can be located inside the housing.

[0132] Additionally, it should be noted that this embodiment does not limit the shape of the box. For example, the box can be a regular shape such as a cuboid or a cylinder, or of course, it can also be other irregular shapes.

[0133] In one possible implementation, the enclosure can be a rectangular structure, and the size of the enclosure can be greater than or equal to the size of the battery cell assembly 100, so that the enclosure can bear the load.

[0134] It should be noted that the specific structure of the battery cell assembly 100 will not be limited here, but can be referred to the above.

[0135] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0136] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A battery cell assembly (100), characterized in that, include: Positive electrode plate (110), the positive electrode plate (110) includes a positive electrode body (111) and a positive electrode tab (112) that are electrically connected. A negative electrode (120) is located on at least one side of the positive electrode (110); A separator (130) is located between adjacent positive electrode plates (110) and negative electrode plates (120); An insulating layer (140) is located between the positive electrode tab (112) and the positive electrode body (111); at least a portion of the insulating layer (140) is disposed on opposite sides of the positive electrode body (111), and another portion of the insulating layer (140) is disposed on opposite sides of the positive electrode tab (112).

2. The cell assembly (100) according to claim 1, characterized in that, The positive electrode body (111) includes a positive electrode current collector and positive electrode active material layers respectively disposed on opposite sides of the positive electrode current collector; At least a portion of the insulating layer (140) is disposed on opposite sides of the positive current collector and covers the negative electrode sheet (120).

3. The cell assembly (100) according to claim 2, characterized in that, Along the height direction of the positive electrode (110), the height of at least a portion of the insulating layer (140) covering the negative electrode (120) is between 1 mm and 2 mm.

4. The cell assembly (100) according to any one of claims 1-3, characterized in that, The battery cell assembly (100) further includes a positive electrode connector (150), the first end of the positive electrode tab (112) is electrically connected to the positive electrode body (111), and the second end of the positive electrode tab (112) is electrically connected to the positive electrode connector (150). Another portion of the insulating layer (140) is disposed on opposite sides of the first end of the positive electrode tab (112).

5. The cell assembly (100) according to claim 4, characterized in that, The insulating layer (140) is a soft-hard composite insulating layer (140).

6. The cell assembly (100) according to claim 4, characterized in that, The insulating layer (140) includes a first insulator layer (141) and a second insulator layer (142). The first insulator layer (141) is disposed on opposite sides of the positive electrode body (111), and the second insulator layer (142) is disposed on opposite sides of the positive electrode tab (112); The first insulator layer (141) is a rigid insulation layer (140), and the second insulator layer (142) is a soft insulation layer (140).

7. The cell assembly (100) according to claim 6, characterized in that, Along the height direction of the positive electrode sheet (110), the height of the first insulator layer (141) is between 2 mm and 3 mm; and / or, Along the thickness direction of the positive electrode (110), the thickness of the first insulator layer (141) is between 60 μm and 100 μm.

8. The cell assembly (100) according to claim 6, characterized in that, Along the height direction of the positive electrode sheet (110), the height of the second insulator layer (142) is between 3 mm and 7 mm; and / or, Along the thickness direction of the positive electrode sheet (110), the thickness of the second insulator layer (142) is between 20 μm and 50 μm.

9. The cell assembly (100) according to claim 6, characterized in that, There is a mutually soluble region between the first insulator layer (141) and the second insulator layer (142); Along the height direction of the positive electrode (110), the height of the miscible region is between 0.1 mm and 0.5 mm.

10. A battery box, characterized in that, It includes a housing and a cell assembly (100) as described in any one of claims 1 to 9, wherein the cell assembly (100) is disposed within the housing.

Images