Pole core, battery monomer, battery device and electric equipment

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a pole core, a battery monomer, a battery device and electric equipment, and the pole core comprises at least one positive plate and at least one negative plate which are laminated along a first direction, the orthographic projection of at least one side of the positive plate in the first direction is overlapped with the side of the orthographic projection of the negative plate in the first direction or is positioned on the outer side of the orthographic projection of the negative plate in the first direction; and the distance h between the orthographic projection of at least one side of the positive plate in the first direction and the orthographic projection of the negative plate in the first direction meets the condition that h is more than or equal to 0 and less than or equal to 3mm. The risk of edge collapse and bending of the pole core is low, so that the edge short circuit probability is low.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to electrode cores, battery cells, battery devices, and electrical equipment. Background Technology

[0002] The battery core typically employs a negative electrode overhang design, meaning the edge of the negative electrode extends beyond the edge of the positive electrode. This design is prone to collapse and bending during high-pressure bonding processes (such as isostatic pressing in solid-state batteries), leading to edge short-circuit failure. Related technologies primarily address this by adding inactive support materials to the overhang region or using special encapsulation materials or techniques to treat the overhang edge, providing additional support and protection to prevent bending and peeling. However, these methods increase the overall size and weight of the battery and require additional processing steps. Therefore, the technical problem of the negative electrode overhang design being susceptible to collapse and bending, leading to edge short-circuit failure, still requires improvement. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, this invention proposes an electrode core, battery cell, battery device, and electrical equipment with low risk of edge collapse and bending, and low probability of short circuit.

[0004] In a first aspect, this application provides an electrode core. According to an embodiment of this application, the electrode core includes at least one positive electrode and at least one negative electrode stacked along a first direction, wherein the orthographic projection of at least one side of the positive electrode in the first direction overlaps with or is located outside the orthographic projection of the negative electrode in the first direction, and the distance h between the orthographic projection h of at least one side of the positive electrode in the first direction and the orthographic projection h of the negative electrode in the first direction satisfies: 0 ≤ h ≤ 3 mm. In the electrode core of this application, the positive and negative electrode edges are aligned (i.e., the orthogonal projection of at least one side of the positive electrode in the first direction overlaps with the orthogonal projection of the negative electrode in the first direction) or the positive electrode overhang is designed (i.e., the orthogonal projection of at least one side of the positive electrode in the first direction is located outside the orthogonal projection of the negative electrode in the first direction). Since the thickness of the positive electrode is usually greater than that of the negative electrode, the electrode gap in the positive electrode overhang region is reduced, decreasing the compressibility. This allows the electrode core to maintain structural integrity and consistency during high-pressure pressing, thereby reducing the risk of collapse and bending due to thickness differences and improving the problem of short circuits caused by deformation during isostatic pressing of the electrode core. Further control of h to meet the above range ensures that the portion of the positive electrode extending beyond the negative electrode is within the bendable angle range, resulting in a larger radius of curvature at the bend. This prevents the formation of sharp shapes at the bend, thus reducing the likelihood of cracking and lowering the probability of increased short circuits due to cracked areas.

[0005] According to an embodiment of this application, 0 ≤ h ≤ 1 mm.

[0006] According to an embodiment of this application, the electrode core includes an electrode core body region and a first extension region; the positive electrode sheet and the negative electrode sheet overlap in the first direction to form the electrode core body region, and the positive electrode sheet extends beyond the electrode core body region in the second direction to form the first extension region, wherein the second direction is perpendicular to the first direction.

[0007] According to an embodiment of this application, the electrode core has a first side and a second side opposite to each other in the first direction, and the acute angle A between the plane containing the surface of the first side of the electrode core body region and the plane containing the surface of the first side of the first extension region satisfies: 0°≤A≤30°; and / or the acute angle B between the plane containing the surface of the second side of the electrode core body region and the plane containing the surface of the second side of the first extension region satisfies: 0°≤B≤30°.

[0008] According to an embodiment of this application, the acute angle A satisfies: 0°≤A≤10°; and / or the acute angle B satisfies: 0°≤B≤10°.

[0009] According to an embodiment of this application, the surface of the first side of the core body region and the surface of the first side of the first extension region are connected by a first transition surface, wherein the radius of curvature R1 of the first transition surface satisfies: 1mm≤R1≤30mm; and / or, the surface of the second side of the core body region and the surface of the second side of the first extension region are connected by a second transition surface, wherein the radius of curvature R2 of the second transition surface satisfies: 1mm≤R2≤30mm.

[0010] According to an embodiment of this application, the radius of curvature R1 satisfies: 20mm≤R1≤30mm; and / or, the radius of curvature R2 satisfies: 20mm≤R2≤30mm.

[0011] According to an embodiment of this application, the first direction is the thickness direction of the positive electrode and the negative electrode, and the length and width directions of the positive electrode and the negative electrode are the same. The second direction is the width direction of the positive electrode and the negative electrode. At least one short side of the positive electrode in the length direction is connected to a tab. Along the width direction, at least one long side of the positive electrode in the width direction extends beyond the corresponding long side of the negative electrode.

[0012] According to an embodiment of this application, at least one short side of the negative electrode extends beyond the corresponding short side of the positive electrode in the length direction, and the portion of the negative electrode extending beyond the positive electrode in the length direction is stacked to form a second extension region.

[0013] According to an embodiment of this application, the electrode core further includes an electrolyte layer, which is composite on at least one side surface of the positive electrode sheet along the first direction.

[0014] According to an embodiment of this application, the electrolyte layer is laminated on opposite sides of the positive electrode sheet along the first direction to form a composite positive electrode, wherein the thickness of the composite positive electrode is more than three times the thickness of the negative electrode sheet.

[0015] According to an embodiment of this application, the electrolyte layer is also composited on at least one side surface of the negative electrode.

[0016] According to an embodiment of this application, along the first direction, the ratio Q of the minimum thickness of the end of the first extension region away from the electrode core body region to the thickness of the electrode core body region satisfies: 100% ≥ Q ≥ 55%.

[0017] According to an embodiment of this application, 100% ≥ Q ≥ 70%.

[0018] In a second aspect, this application provides a battery cell. According to an embodiment of this application, the battery cell includes the electrode core described above. This battery cell possesses all the features and advantages of the electrode core described above, which will not be repeated here.

[0019] A third aspect of this application provides a battery device. According to an embodiment of this application, the battery device includes the battery cell described above. This battery device possesses all the features and advantages of the battery cell described above, which will not be repeated here.

[0020] In a fourth aspect, this application provides an electrical device. According to embodiments of this application, the electrical device includes the aforementioned battery cell or battery assembly. This electrical device has a low short-circuit risk and high safety. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the electrode core according to an embodiment of this application.

[0022] Figure 2 This is a schematic diagram of the positive and negative electrode plates of one embodiment of this application, projected in a first direction.

[0023] Figure 3 This is a schematic diagram of the structure of the electrode core according to another embodiment of this application.

[0024] Figure 4 yes Figure 3 Enlarged view of the position indicated by the circle on the first side of the central electrode core.

[0025] Figure 5 yes Figure 3Enlarged view of the position indicated by the circle on the second side of the middle electrode core.

[0026] Figure 6 This is a schematic diagram of the positive and negative electrode plates of one embodiment of this application, projected in a first direction. Detailed Implementation

[0027] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0028] In a first aspect, this application provides an electrode core. According to an embodiment of this application, referring to... Figure 1 and Figure 2 The electrode core 100 includes at least one positive electrode 10 and at least one negative electrode 20 stacked along a first direction, wherein the orthographic projection of at least one side 11 of the positive electrode 10 in the first direction overlaps with the side of the orthographic projection of the negative electrode 20 in the first direction or is located outside the orthographic projection of the negative electrode 20 in the first direction, and the distance h (or positive electrode overhang dimension) between the orthographic projection of at least one side 11 of the positive electrode 10 in the first direction and the orthographic projection of the negative electrode 20 in the first direction satisfies: 0≤h≤3mm.

[0029] In the electrode core of this application, the positive and negative electrode edges are aligned (i.e., the orthogonal projection of at least one side of the positive electrode in the first direction overlaps with the orthogonal projection of the negative electrode in the first direction) or the positive electrode overhang is designed (i.e., the orthogonal projection of at least one side of the positive electrode in the first direction is located outside the orthogonal projection of the negative electrode in the first direction). Since the thickness of the positive electrode is usually greater than that of the negative electrode, the electrode gap in the positive electrode overhang region is reduced, thus reducing the compressibility. Therefore, the deformation in the positive electrode overhang region is reduced, which allows the electrode core to maintain structural integrity and consistency during high-pressure pressing, thereby reducing the risk of collapse and bending caused by thickness differences and improving the problem of short circuits caused by deformation during isostatic pressing of the electrode core. Further controlling h to meet the above range ensures that the portion of the positive electrode extending beyond the negative electrode is within the bendable angle range, and the radius of curvature of the bend is large, meaning that the bend is less likely to form a sharp shape, and therefore less likely to crack, reducing the possibility of increased short circuit probability due to cracked areas.

[0030] As an example, the distance h between the orthographic projection of at least one side 11 of the positive electrode 10 in the first direction and the orthographic projection of the negative electrode 20 in the first direction can specifically be 0.1mm~3mm, 0.5mm~2.5mm, 1mm~2mm, etc., and more specifically, it can be 0mm, 0.2mm, 0.4mm, 0.6mm, 0.8mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, etc. In some preferred embodiments, the distance h between the orthographic projection of at least one side 11 of the positive electrode 10 in the first direction and the orthographic projection of the negative electrode 20 in the first direction satisfies 0≤h≤1mm. This further benefits the portion of the positive electrode extending beyond the negative electrode, allowing for a larger radius of curvature during bending within the bendable angle range. This means the bend is less likely to form a sharp shape, thus reducing the likelihood of cracking and further decreasing the probability of a short circuit due to a cracked area.

[0031] According to the embodiments of this application, referring to Figure 1 and Figure 2 The electrode core 100 includes a core body region 110 and a first extension region 120. The positive electrode sheet 10 and the negative electrode sheet 20 overlap in the first direction to form the core body region 110, and the portion 13 of the positive electrode sheet 10 extending beyond the core body region 110 in the second direction is stacked to form the first extension region 120, where the second direction is perpendicular to the first direction. In other words, the portion of the positive electrode sheet edge extending beyond the negative electrode sheet (i.e., the positive electrode sheet overhang region) constitutes the first extension region of the electrode core, i.e., the positive electrode sheet overhang region. This design further reduces the risk of electrode core collapse and bending, and improves the problem of short circuits caused by deformation during isostatic pressing of the electrode core.

[0032] It should be noted that the length of the first extension region in the second direction is the aforementioned positive electrode overhang dimension h (see structural diagram for reference). Figure 3 ).

[0033] According to the embodiments of this application, referring to Figure 3 The electrode core 100 has a first side and a second side opposite to each other in the first direction. The acute angle A between the plane containing the surface 101 of the first side of the electrode core body region and the plane containing the surface 121 of the first side of the first extension region satisfies: 0°≤A≤30°; and / or the acute angle B between the plane containing the surface 102 of the second side of the electrode core body region and the plane containing the surface 122 of the second side of the first extension region satisfies: 0°≤B≤30°. Controlling the included angles A and B within the above-mentioned angle range can further reduce the short-circuit rate.

[0034] As an example, the aforementioned included angle A can specifically be 5°–30°, 5°–25°, 5°–20°, etc., and more specifically, it can be 0°, 5°, 10°, 15°, 20°, 25°, 30°, etc. The aforementioned included angle B can specifically be 5°–30°, 5°–25°, 5°–20°, etc., and more specifically, it can be 0°, 5°, 10°, 15°, 20°, 25°, 30°, etc. In some preferred embodiments, the aforementioned included angle A can specifically be 0°–10°; the aforementioned included angle B can specifically be 0°–10°. Therefore, the short-circuit rate can be further reduced.

[0035] In this paper, the method for measuring the aforementioned included angle A is as follows: Cut the pole core along a centerline perpendicular to the large surface of the pole core (i.e., parallel to the first direction) and parallel to the length direction of the pole core to obtain a cross section. Measure the included angle formed by the intersection of the first side surface intersection line of the pole core main body region and the first side surface intersection line of the first extension region (ignoring the arc-shaped area at the intersection). Then subtract this included angle from 180° to obtain the aforementioned included angle A. Similarly, the aforementioned included angle B can be measured using the same method.

[0036] It should be noted that the aforementioned included angles A and B can also be called overhang angles. Generally, the first and second sides of the electrode core are symmetrical. One of the first and second sides can be randomly selected for testing to obtain the overhang angle.

[0037] According to the embodiments of this application, referring to Figure 4 The surface 101 on the first side of the core body region and the surface 121 on the first side of the first extension region are connected by a first transition surface 1. The radius of curvature R1 of the first transition surface 1 satisfies: 1mm ≤ R1 ≤ 30mm. For example, R1 can specifically be 5mm–25mm, 5mm–20mm, 10mm–30mm, etc., and more specifically, it can be 1mm, 3mm, 5mm, 8mm, 10mm, 12mm, 15mm, 18mm, 20mm, 22mm, 25mm, 28mm, 30mm, etc. In some preferred embodiments, R1 satisfies: 20mm ≤ R1 ≤ 30mm. With R1 within the above range, the problems of collapse and short circuit in the first extension region can be further improved.

[0038] According to the embodiments of this application, referring to Figure 5The surface 102 on the second side of the core body region and the surface 122 on the second side of the first extension region are connected by a second transition surface 2. The radius of curvature R2 of the second transition surface 2 satisfies: 1mm ≤ R2 ≤ 30mm. For example, R2 can specifically be 5mm–25mm, 5mm–20mm, 10mm–30mm, etc., and more specifically, it can be 1mm, 3mm, 5mm, 8mm, 10mm, 12mm, 15mm, 18mm, 20mm, 22mm, 25mm, 28mm, 30mm, etc. In some preferred embodiments, R2 satisfies: 20mm ≤ R2 ≤ 30mm. With R2 within the above range, the problems of collapse and short circuit in the first extension region can be further improved.

[0039] In this paper, the measurement method for R1 can be as follows: A cross-section is obtained by cutting the pole core along a centerline perpendicular to the large surface of the pole core and parallel to the length direction of the pole core. The radius of curvature of the arc-shaped region at the intersection of the first surface intersection line of the pole core main body region and the first side surface intersection line of the first extension region formed by the cross-section is measured. This radius of curvature can be measured using an image measuring instrument. Similarly, R2 can be tested using the same method.

[0040] It should be noted that R1 and R2 mentioned above can also be called overhang curvature radius. Generally, the first and second sides of the pole core are symmetrical. One of the first and second sides can be randomly selected for testing to obtain the overhang curvature radius.

[0041] According to embodiments of this application, the electrode core can be rectangular, and correspondingly, the positive and negative electrode sheets can also be rectangular. The tabs are connected to the short side of the electrode core, meaning the edge of the long side of the positive electrode sheet is aligned with the edge of the long side of the negative electrode sheet, or the edge of the long side of the positive electrode sheet extends beyond the edge of the long side of the negative electrode sheet. In some embodiments, the edge of the long side of the positive electrode sheet may extend beyond the edge of the long side of the negative electrode sheet, and the edge of the short side of the negative electrode sheet may extend beyond the edge of the short side of the positive electrode sheet. This significantly reduces the risk of electrode core edge collapse or bending, thus lowering the probability of a short circuit.

[0042] According to the embodiments of this application, referring to Figure 6The first direction is the thickness direction of the positive electrode 10 and the negative electrode 20, and the length and width directions of the positive electrode 10 and the negative electrode 20 are the same. The second direction is the width direction of the positive electrode and the negative electrode. At least one short side of the positive electrode 10 in the length direction is connected to a tab. Along the width direction, at least one long side 14 of the positive electrode 10 in the width direction extends beyond the long side 21 of the negative electrode 20. In the electrode core of this application, the long side of the positive electrode (i.e., the non-tab side, the extension direction of the long side is parallel to the length direction) extends beyond the edge of the negative electrode. This is because the long side is usually the cutting edge during the manufacturing process, and there are no other parts on its outside, making it more prone to collapse during isostatic pressing. The design of this application can significantly reduce the risk of this edge collapsing or bending.

[0043] According to the embodiments of this application, referring to Figure 6 At least one short side 22 of the negative electrode 20 extends beyond the corresponding short side 15 of the positive electrode 10 along the length direction. The portion of the negative electrode 20 extending beyond the positive electrode 10 in the length direction is stacked to form a second extension region 23 (or negative electrode overhang region). Thus, a configuration of a long-side positive electrode overhang and a short-side negative electrode overhang is formed, thereby improving the short-circuit rate of the long-side overhang while maintaining a high positive electrode utilization rate near the short-side overhang.

[0044] According to the embodiments of this application, referring to Figure 1 The electrode core also includes an electrolyte layer 40, which is laminated onto at least one side surface of the positive electrode 10 along the first direction. In some embodiments, the electrolyte layer 40 is laminated onto opposite side surfaces of the positive electrode 10 along the first direction to form a composite positive electrode. This allows for more flexible control and optimization of the thickness of the first extension region, further reducing the risk of collapse and bending of the first extension region and improving the short-circuit problem caused by isostatic deformation of the electrode core.

[0045] According to an embodiment of this application, the electrolyte layer is laminated on opposite side surfaces of the positive electrode sheet along the first direction to form a composite positive electrode. The thickness h1 of the composite positive electrode is more than three times the thickness h2 of the negative electrode sheet. Within the aforementioned thickness range, the electrode gap in the first extension region can be further reduced, decreasing the compressibility and thus reducing the deformation of the first extension region. This reduces the thickness difference between the electrode core body region and the first extension region, thereby providing a more uniform stress state in the transition region between the electrode core body region and the first extension region. This allows the electrode core to maintain structural integrity and consistency during isostatic pressing, thereby reducing the risk of collapse and bending due to thickness differences and improving the problem of short circuits caused by deformation during isostatic pressing of the electrode core.

[0046] As an example, the thickness h1 of the composite positive electrode is 3 to 20 times, 3 to 15 times, or 3 to 10 times the thickness h2 of the negative electrode. Specifically, the thickness h1 of the composite positive electrode can be 3, 4, 5, 6, 7, 8, 9, or 10 times the thickness h2 of the negative electrode.

[0047] According to embodiments of this application, the electrolyte layer is further laminated on at least one surface of the negative electrode sheet. As an example, the electrolyte layer can be laminated on opposite sides of the negative electrode sheet. This allows for more flexible control and optimization of the thickness of the first extension region, further reducing the risk of collapse and bending of the first extension region, and mitigating short-circuit problems caused by isostatic deformation of the electrode core.

[0048] In this article, "electrolyte layer composite on the surface of the positive electrode" refers to the electrolyte layer being fixedly connected to the positive electrode to form an integral composite positive electrode structure. Specifically, the electrolyte layer can be formed by directly coating the electrolyte-containing slurry onto the electrode; alternatively, the electrolyte-containing slurry can be coated onto aluminum foil first and then transferred onto the positive electrode. Similarly, "electrolyte layer composite on the surface of the negative electrode" has a similar meaning.

[0049] According to embodiments of this application, along the first direction, the ratio Q (or Overhang thickness ratio) of the minimum thickness h3 of the first extension region at the end furthest from the electrode core body region to the thickness h4 of the electrode core body region satisfies: 100% ≥ Q ≥ 55%. Specifically, Q can be 55%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, etc. In some preferred embodiments, Q satisfies 100% ≥ Q ≥ 70%. Within the above ratio range, the risk of collapse and bending of the positive electrode overhang region is lower, and the possibility of electrode core short circuit is lower.

[0050] It is understood that the specific structure of the electrode core according to the embodiments of this application is not particularly limited, and can be any electrode core structure known in the art. As an example, the electrode core may include a plurality of positive electrode plates, a plurality of negative electrode plates, and an electrolyte layer disposed between two adjacent positive electrode plates and negative electrode plates, wherein the electrolyte layer may be a separate layer structure, or it may be composited on the positive electrode plate and / or the negative electrode plate.

[0051] In a second aspect, this application provides a battery cell. According to an embodiment of this application, the battery cell includes the electrode core described above. This battery cell possesses all the features and advantages of the electrode core described above, which will not be repeated here.

[0052] According to embodiments of this application, the battery cell may include the aforementioned electrode core and outer packaging, with the electrode core encapsulated within the outer packaging. Depending on the shape of the battery cell, it may include a square battery cell, a cylindrical battery cell, etc. Depending on the type of outer packaging, the battery cell may include a hard-shell battery cell and a pouch battery cell, etc. Depending on the type of active ions, the battery cell may include a lithium-ion battery, a sodium-ion battery, etc.

[0053] A third aspect of this application provides a battery device. According to an embodiment of this application, the battery device includes the battery cell described above. This battery device possesses all the features and advantages of the battery cell described above, which will not be repeated here.

[0054] It is understood that there are no particular limitations on the type of battery device, which may include battery modules, battery packs, etc. Specifically, the specific structure of battery modules and battery packs can be referred to conventional technology in this field, and will not be described in detail here.

[0055] In a fourth aspect, this application provides an electrical device. According to embodiments of this application, the electrical device includes the aforementioned battery cell or battery assembly. This electrical device has a low short-circuit risk and high safety.

[0056] According to embodiments of this application, the specific type of electrical equipment is not particularly limited and can be any device that uses a single battery cell or battery device as a power source or energy storage unit. As examples, electrical equipment includes, but is not limited to, 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.), mobile terminals (e.g., mobile phones, laptops, game consoles, wearable devices, etc.), drones, aerospace equipment, satellites, ships, energy storage systems, etc.

[0057] It is understood that, in addition to the battery cells or battery devices mentioned above, the electrical equipment also includes other necessary structures and components, all of which can be made with reference to conventional technologies. For example, an electric vehicle may include a body, chassis, tires, navigation system, radar system, steering system, braking system, lubrication system, cooling system, driving system, etc., which will not be described in detail here.

[0058] The present application will now be described with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present application in any way. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in the art or in accordance with the product manual.

[0059] In the following examples and comparative examples, the short circuit rate was tested as follows: the open circuit voltage of the positive and negative poles of the electrode core was tested, and a short circuit was determined when the open circuit voltage was less than 200mV.

[0060] In the following table, unless otherwise specified, the Overhang dimensions, Overhang angles, and Overhang curvature radii refer to the Overhang dimensions, Overhang angles, and Overhang curvature radii corresponding to the longer side of the positive pole.

[0061] Example 1

[0062] Electrode core fabrication: 40 layers of composite positive electrode (i.e., positive electrode sheets with electrolyte layers laminated on opposite sides, the electrolyte layer being a sulfide-based electrolyte) and 39 layers of negative electrode sheets are sequentially stacked, and then formed into an electrode core using an isostatic pressing process. The positive electrode sheet includes an aluminum foil current collector and positive electrode coating layers (composed of ternary positive electrode material) located on both sides of the aluminum foil current collector, with a composite positive electrode thickness of 260 μm; the negative electrode sheet includes a copper foil current collector and negative electrode coating layers (composed of silicon-based negative electrode material) located on both sides of the copper foil current collector, with a negative electrode thickness of 40 μm.

[0063] Adjust the overhang dimensions of the positive electrode (i.e., the distance h between the orthogonal projection of the positive electrode in the first direction and the orthogonal projection of the negative electrode in the first direction) to 0mm, 0.1mm, 0.3mm, 0.5mm, 0.8mm, 1mm, 1.5mm, 2mm, 2.5mm, and 3mm respectively, and the overhang dimension of the negative electrode is 1.5mm for all of them, to obtain electrode cores numbered 1-1, 1-2, ..., 1-10 respectively. The specific parameters are shown in Table 1.

[0064] Comparative Example 1

[0065] Same as Example 1, except that: the Overhang size of the positive electrode (i.e., the distance h between the positive electrode's long side projection in the first direction and the negative electrode's projection in the first direction) is adjusted to 3.1mm, 3.5mm, and 4mm respectively, to obtain electrode cores numbered D1-1, D1-2, and D1-3 respectively. The specific parameters of the positive electrode overhang and the electrode core short-circuit rate test data are shown in Table 1.

[0066] Table 1

[0067]

[0068] Example 2

[0069] Similar to Example 1, the difference is that the Overhang angle (i.e., the included angle A or included angle B mentioned above, randomly selecting one of the first and second sides for testing) is adjusted by different positive electrode layer numbers and thicknesses, negative electrode layer numbers and thicknesses, and Overhang dimensions. The Overhang angles are designed as 0°, 4.5°, 15°, 18°, 25°, 30°, 35°, and 45°, resulting in electrode cores numbered 2-1, 2-2, ..., 2-8, respectively. The specific parameters are shown in Table 2.

[0070] Example 3

[0071] Same as Example 2, except that: the short side (tab side) of the electrode core is set as the negative electrode overhang, that is, the short side of the negative electrode sheet extends beyond the edge of the short side of the positive electrode sheet in the length direction. Specifically, the size of the negative electrode overhang is 2.5mm and the size of the positive electrode overhang is 2mm, resulting in an electrode core numbered 3-1. The specific parameters are shown in Table 2.

[0072] Example 4

[0073] Same as Example 3, except that: an electrolyte layer is composited on both sides of the negative electrode sheet, and the thickness of the composite negative electrode sheet is 110μm, resulting in an electrode core numbered 4-1. Specific parameters are shown in Table 2.

[0074] Comparative Example 2

[0075] Same as Example 4, except that: the long side negative electrode is overhang, the thickness of the positive electrode is 200μm, the thickness of the composite negative electrode containing the electrolyte layer is 70μm, the number of electrode core stack layers is 43 layers of positive electrode and 44 layers of composite negative electrode, resulting in an electrode core numbered D2-1. Other parameters are shown in Table 2.

[0076] Table 2

[0077]

[0078] Example 5

[0079] Similar to Example 1, the difference is that the Overhang curvature radius (i.e., R1 or R2 above, which can be randomly selected from the first side and the second side for testing) is adjusted by different layers and thicknesses. The Overhang curvature radii are designed as follows: 1mm, 3mm, 5mm, 8mm, 13mm, 21mm, 30mm, 31mm, 35mm, 40mm, 0.5mm, and 0.9mm, respectively, to obtain pole cores numbered 5-1, 5-2, ..., 5-9. Other parameters are shown in Table 3.

[0080] Comparative Example 3

[0081] Similar to Example 5, the specific differences in parameters are shown in Table 3, resulting in a pole core numbered D3-1.

[0082] Comparative Example 4

[0083] Similar to Example 5, with specific differences in parameters shown in Table 3, the pole cores numbered D4-1, D4-2, and D4-3 were obtained.

[0084] Table 3

[0085]

[0086] The test data above shows that designing a positive overhang can effectively reduce the short circuit rate. Further controlling the overhang size, overhang radius of curvature, overhang angle, and overhang thickness ratio within the range of this application can further reduce the short circuit rate.

[0087] In the description of this application, 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 indicated technical features. 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.

[0088] 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.

[0089] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are 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.

[0090] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. An electrode core, characterized in that, The device includes at least one positive electrode and at least one negative electrode stacked along a first direction, wherein the orthogonal projection of at least one side of the positive electrode in the first direction overlaps with or is located outside the orthogonal projection of the negative electrode in the first direction, and the distance h between the orthogonal projection of at least one side of the positive electrode in the first direction and the orthogonal projection of the negative electrode in the first direction satisfies: 0 ≤ h ≤ 3 mm.

2. The electrode core according to claim 1, characterized in that, 0≤h≤1mm.

3. The electrode core according to claim 1, characterized in that, The electrode core includes an electrode core body region and a first extension region; The positive electrode and the negative electrode overlap in the first direction to form the core body region, and the positive electrode extends beyond the core body region in the second direction to form the first extension region, wherein the second direction is perpendicular to the first direction.

4. The electrode core according to claim 3, characterized in that, The pole core has a first side and a second side opposite to each other in the first direction. The acute angle A between the plane containing the surface of the first side of the core body region and the plane containing the surface of the first side of the first extension region satisfies: 0°≤A≤30°; and / or the acute angle B between the plane containing the surface of the second side of the core body region and the plane containing the surface of the second side of the first extension region satisfies: 0°≤B≤30°.

5. The electrode core according to claim 4, characterized in that, The acute angle A satisfies: 0°≤A≤10°; and / or the acute angle B satisfies: 0°≤B≤10°.

6. The electrode core according to claim 3, characterized in that, The surface on the first side of the core body region and the surface on the first side of the first extension region are connected by a first transition surface, wherein the radius of curvature R1 of the first transition surface satisfies: 1mm ≤ R1 ≤ 30mm; and / or, The surface on the second side of the core body region and the surface on the second side of the first extension region are connected by a second transition surface, and the radius of curvature R2 of the second transition surface satisfies: 1mm≤R2≤30mm.

7. The electrode core according to claim 6, characterized in that, The radius of curvature R1 satisfies: 20mm ≤ R1 ≤ 30mm; and / or, The radius of curvature R2 satisfies: 20mm≤R2≤30mm.

8. The electrode core according to claim 3, characterized in that, The first direction is the thickness direction of the positive electrode and the negative electrode, and the length and width directions of the positive electrode and the negative electrode are the same. The second direction is the width direction of the positive electrode and the negative electrode. At least one short side of the positive electrode in the length direction is connected to a tab. Along the width direction, at least one long side of the positive electrode in the width direction extends beyond the corresponding long side of the negative electrode.

9. The electrode core according to claim 8, characterized in that, At least one short side of the negative electrode extends beyond the corresponding short side of the positive electrode in the length direction, and the portion of the negative electrode extending beyond the positive electrode in the length direction is stacked to form a second extension region.

10. The electrode core according to any one of claims 1 to 9, characterized in that, It also includes an electrolyte layer, which is laminated on at least one side surface of the positive electrode along the first direction.

11. The electrode core according to claim 10, characterized in that, The electrolyte layer is laminated on opposite sides of the positive electrode sheet along the first direction to form a composite positive electrode.

12. The electrode core according to claim 11, characterized in that, The thickness of the composite positive electrode is more than three times the thickness of the negative electrode sheet.

13. The electrode core according to claim 10, characterized in that, The electrolyte layer is also laminated on at least one side surface of the negative electrode.

14. The electrode core according to any one of claims 3 to 9, characterized in that, Along the first direction, the ratio Q of the minimum thickness of the end of the first extension region away from the electrode core body region to the thickness of the electrode core body region satisfies: 100% ≥ Q ≥ 55%.

15. The electrode core according to claim 14, characterized in that, 100％≥Q≥70％。 16. A single battery cell, characterized in that, The electrode core includes any one of claims 1 to 15.

17. A battery device, characterized in that, Includes the battery cell as described in claim 16.

18. An electrical appliance, characterized in that, Includes the battery cell of claim 16 or the battery device of claim 17.

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