Battery

Abstract

This utility model relates to the field of battery technology and discloses a battery, including a cell and a casing. The cell includes a positive electrode and a negative electrode. The positive electrode has a positive active material layer covering at least a portion of the surface of the positive electrode body, and an insulating layer covering at least a portion of the surface of the positive electrode tab. The negative electrode includes a negative current collector and a negative active material layer. The negative current collector includes a negative electrode body, and the surface of the negative electrode body is provided with the negative active material layer. The insulating layer is connected to a first edge of the positive active material layer, and the positive electrode tab is connected to a second edge of the positive electrode body. The negative electrode body includes a main body region and a protruding region. The third edge of the protruding region extends beyond the fourth edge of the main body region. The distance between the second and fourth edges is D, and the distance between the first and third edges is B, satisfying that B ≥ D, 0.2 mm ≤ B ≤ 1.5 mm, and 0.1 mm ≤ D ≤ 0.7 mm. This utility model can reduce the risk of lithium plating and reduce negative electrode waste, which is beneficial to improving the energy density of the battery.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to batteries. Background Technology

[0002] With the rapid development of new energy technologies, batteries are being used more and more widely. Batteries are increasingly being used in electronic devices and electric vehicles.

[0003] The negative electrode of the battery needs to cover the positive electrode, and the edge of the negative electrode needs to extend beyond the edge of the positive electrode to ensure a safe distance between the edges of the negative electrode active material layer and the edges of the positive electrode active material layer, thereby preventing lithium plating. At the same time, an insulating layer is coated at the base of the positive electrode tab to prevent internal short circuits caused by burrs, compression, vibration, etc., thus improving battery safety.

[0004] Errors exist in both the coating of the insulating layer and the coating of the positive electrode active material layer, resulting in deviations at the interface between the positive electrode active material layer and the insulating layer. This leads to a failure to guarantee the safe distance between the edge of the positive electrode active material layer near the insulating layer and the edge of the negative electrode active material layer. Existing technologies increase the excess dimension of the negative electrode sheet beyond the positive electrode sheet to allow for greater margins and ensure the aforementioned safe distance. However, this design results in excessive waste of negative electrode sheet margins, leading to low battery energy density. Utility Model Content

[0005] In view of this, the present invention provides a battery to solve the problem of low energy density of the battery due to excessive negative electrode excess in the prior art.

[0006] This utility model provides a battery, including a battery cell and a casing. The battery cell is disposed within the casing. The battery cell includes: a positive electrode sheet, comprising a positive current collector, a positive active material layer and an insulating layer disposed on the surface of the positive current collector, the positive current collector including a positive electrode sheet body and a positive electrode tab, the positive active material layer at least covering a portion of the surface of the positive electrode sheet body, the insulating layer at least covering a portion of the surface of the positive electrode tab, the insulating layer being connected to a first edge of the positive active material layer along a first direction, and the positive electrode tab being connected to a second edge of the positive electrode sheet body; and a negative electrode sheet, stacked with the positive electrode sheet, the negative electrode sheet including a negative current collector and a negative active material layer disposed on the surface of the negative current collector, the negative current collector including a negative electrode sheet body, the surface of the negative electrode sheet body being provided with... The negative electrode active material layer; the negative electrode body includes a main body region and a protruding region. Along a first direction, the protruding region protrudes from the main body region such that the third edge of the protruding region extends beyond the fourth edge of the main body region. The first edge, the second edge, the third edge, and the fourth edge are all located on the same side of the positive electrode tab in the first direction. The stacking direction of the positive electrode sheet and the negative electrode sheet is perpendicular to the first direction. The orthographic projection of the positive electrode tab along the stacking direction at least partially overlaps with the orthographic projection of the protruding region along the stacking direction. Along the first direction, the distance between the second edge and the fourth edge is D, and the distance between the first edge and the third edge is B, satisfying that B≥D, 0.2mm≤B≤1.5mm, and 0.1mm≤D≤0.7mm.

[0007] In some embodiments, the distance between the third edge and the fourth edge is A, which satisfies 0.1mm≤A≤2mm.

[0008] In some embodiments, the negative current collector further includes a negative electrode tab connected to the fourth edge of the main body region; along the second direction, the distance between the negative electrode tab and the protruding region is G, satisfying that G≥2mm, and the second direction, the first direction, and the stacking direction are perpendicular to each other; and / or, along the second direction, the two opposite edges of the protruding region extend beyond the opposite two sides of the positive electrode tab by an extension dimension of E, satisfying that E≥0.2mm.

[0009] In some embodiments, the two sides of the protruding area at the corner are connected by an arc transition; or, the two sides of the protruding area at the corner are connected by a rounded transition, and the radius of the rounded corner is R, satisfying 0.5mm≤R≤10mm.

[0010] In some embodiments, along the first direction, the third edge of the protruding region is shortened to the fifth edge of the insulating layer on the positive electrode tab that is far from the positive electrode active material layer, and the distance between the third edge and the fifth edge is J, satisfying that J≥0.7mm.

[0011] In some embodiments, along the first direction, the positive electrode active material layer extends to a portion of the surface of the positive electrode tab and is connected to the insulating layer. The edge on the positive electrode tab where the positive electrode active material layer is connected to the insulating layer is the first edge. The distance between the first edge and the second edge is C1, satisfying that 0≤C1≤1.5mm; or 0≤C1≤0.5mm, 0.1mm≤A≤1mm.

[0012] In some embodiments, along the first direction, the insulating layer extends to a portion of the surface of the positive electrode body and is connected to the positive electrode active material layer, and the distance between the first edge and the second edge is C2, satisfying that 0≤C2≤1.5mm; or 0≤C2≤0.5mm, 0.1mm≤A≤1mm.

[0013] In some embodiments, along the first direction, the distance between the third edge of the protruding area and the inner wall of the outer casing is P1, satisfying 1mm≤P1≤3mm; and / or, along the first direction, the distance between the fourth edge and the inner wall of the outer casing is P2, satisfying 1.2mm≤P2≤4mm.

[0014] In some embodiments, the outer shell includes a shell body portion and a protruding portion. Along the first direction, the protruding portion protrudes from the shell body portion and corresponds to the protruding area. Along the first direction, the distance between the third edge of the protruding area and the inner wall of the protruding portion is P3, the distance between the fourth edge and the inner wall of the shell body portion is P4, and the distance between the outer wall of the shell body portion and the outer wall of the protruding portion is H, satisfying that P3≥P4, 1mm≤P3≤3mm, 0.6mm≤P4≤3mm, and 0.1mm≤H≤5mm.

[0015] In some embodiments, the outer casing is a metal casing or an aluminum-plastic film; and / or, the battery cell is a stacked structure, and the battery cell further includes a separator disposed between the positive electrode and the negative electrode.

[0016] Beneficial effects: This invention, by setting a negative electrode sheet with a protruding area, allows for precise control of the distance D between the fourth edge of the negative electrode sheet body area (non-protruding portion) and the second edge of the positive electrode sheet body during manufacturing. This eliminates the need for a pre-reserved allowance in the non-protruding portion of the negative electrode sheet. Furthermore, errors exist in the coating of the insulating layer and the positive active material layer on the surface of the positive current collector corresponding to the protruding area, making it difficult to precisely control the distance B (i.e., the safety distance) between the first and third edges. Therefore, by using a negative electrode sheet with a protruding area, the local size of the negative electrode sheet is increased, allowing for a larger allowance to compensate for the aforementioned errors and ensure the size of B. Compared to the previous method of pre-reserving allowance for the entire negative electrode sheet, this reduces waste of the negative electrode sheet and improves the battery's mass energy density.

[0017] Because errors exist in both the coating of the insulating layer and the coating of the positive electrode active material layer on the surface of the positive electrode current collector, the size of B relative to the size of D is difficult to control. Therefore, B ≥ D can ensure the safe size of B. B > 0.2 mm can ensure the size of B, reduce the risk of lithium plating, and ensure the cycle performance of the battery; however, if B is too large, it will lead to waste of the negative electrode sheet, which is not conducive to improving the mass energy density of the battery. Therefore, 0.2 mm ≤ B ≤ 1.5 mm is beneficial to both ensuring the size of B, reducing the risk of lithium plating, ensuring the cycle performance of the battery, and improving the mass energy density of the battery.

[0018] A diameter (D) greater than or equal to 0.1 mm can reduce the risk of lithium plating and ensure the cycle performance of the battery; however, if D is too large, it will lead to waste of the negative electrode sheet and is not conducive to improving the mass energy density of the battery. Therefore, 0.1 mm ≤ D ≤ 0.7 mm can both reduce the risk of lithium plating and ensure the cycle performance of the battery, and is also conducive to improving the mass energy density of the battery. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the battery cell structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the battery cell structure according to another embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a battery cell according to another embodiment of the present invention; Figure 4This is a schematic diagram of the battery structure according to an embodiment of the present invention; Figure 5 This is a cross-sectional view of the battery according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of a battery according to another embodiment of the present invention.

[0021] Explanation of reference numerals in the attached figures: 1-Cell; 10-Positive electrode sheet; 11-Positive electrode current collector; 111-Positive electrode sheet body; 111a-Second edge; 112-Positive electrode tab; 12-Positive electrode active material layer; 12a-First edge; 13-Insulating layer; 13a-Fifth edge; 20-Negative electrode sheet; 21-Negative electrode current collector; 211-Negative electrode sheet body; 2111-Body area; 2111a-Fourth edge; 2112-Protruding area; 2112a-Third edge; 212-Negative electrode tab; 22-Negative electrode active material layer; 30-Separator; 2-Outer shell; 201-Main shell body; 202-Protruding part; X - First direction; Y - Second direction; Z - Stacking direction. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0023] In battery design and manufacturing, the negative electrode needs to cover the positive electrode, and the edge of the negative electrode needs to extend beyond the edge of the positive electrode to ensure a safe distance between the edges of the negative electrode active material layer and the edges of the positive electrode active material layer, thus preventing lithium plating. At the same time, an insulating layer is coated at the base of the positive electrode tab to prevent internal short circuits caused by burrs, compression, vibration, etc., thereby improving battery safety.

[0024] Errors occur during the coating processes of the insulating layer and the positive electrode active material layer, resulting in a positional deviation at the interface between the positive electrode active material layer and the insulating layer. Specifically, the actual position of the edge of the positive electrode active material layer near the insulating layer differs from the designed position, causing the safe distance between the edge of the positive electrode active material layer near the insulating layer and the edge of the negative electrode active layer to be compromised. Existing technologies increase the oversize of the negative electrode sheet beyond the positive electrode sheet to allow for this deviation and ensure the safe distance. However, this leads to over-design of the negative electrode sheet, wasted negative electrode material, and consequently, low battery energy density.

[0025] To address this issue, this invention creates a protruding area in the local region of the negative electrode sheet corresponding to the positive electrode tab. This compensates for positional deviations that may occur during the coating of the insulating layer and the positive electrode active material layer. By controlling the spacing between the edges of the negative electrode active material layer and the positive electrode active material layer corresponding to the protruding area, as well as the spacing between the edges of the negative electrode active material layer and the positive electrode active material layer corresponding to the non-protruding area, a safe distance between the edges of the negative electrode active material layer and the positive electrode active material layer is ensured. This reduces the risk of lithium plating, minimizes waste of the negative electrode sheet, and improves the mass energy density of the battery.

[0026] The following is combined with Figures 1 to 6 The following describes embodiments of the present invention.

[0027] This utility model provides a battery, including a cell 1 and a casing 2.

[0028] In one specific example, the cell includes a positive electrode, a negative electrode, and a separator located between the positive electrode and the negative electrode; the positive electrode includes a positive current collector, a positive active material layer, and a positive tab extending from one side of the positive current collector; the negative electrode includes a negative current collector and a negative tab extending from one side of the negative current collector; the negative electrode also includes a negative active material layer located on at least one side surface of the negative current collector.

[0029] In some embodiments, the battery cell may be a wound core formed by stacking and winding a positive electrode sheet, a separator, and a negative electrode sheet; in other embodiments, the battery cell may be a stacked core formed by stacking a positive electrode sheet, a separator, and a negative electrode sheet. In a further embodiment, the stacked core includes a topmost and a bottommost electrode sheet along the thickness direction, the topmost and / or bottommost electrode sheet may be a single-sided negative electrode sheet, the single-sided negative electrode sheet including a negative current collector and a layer of negative active material on one side surface of the negative current collector near the center of the battery cell.

[0030] In a specific example, the positive current collector may be, for example, aluminum foil, aluminum alloy foil, or composite current collector (e.g., aluminum-carbon composite current collector), and the thickness of the positive current collector may be, for example, 6μm-15μm (e.g., 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, or 15μm).

[0031] In a specific example, the positive electrode active material layer may include a positive electrode active material, such as lithium nickel cobalt manganese oxide (LiNi). 0.90 Co 0.05 Mn 0.05At least one of the following: O2 (NCM955), NCM811, NCM622, NCM523, NCM111, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium vanadium phosphate, lithium cobalt phosphate, lithium manganese phosphate, lithium manganese iron phosphate, lithium-rich manganese-based materials, lithium cobalt oxide (LiCoO2), lithium iron silicate, lithium vanadium silicate, lithium cobalt silicate, lithium manganese silicate, spinel-type lithium manganese oxide, spinel-type lithium nickel manganese oxide, and lithium titanate.

[0032] In one specific example, the negative electrode current collector may be, for example, copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, or a composite current collector. In one example, the thickness of the negative electrode current collector may be, for example, 4μm-10μm (e.g., 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, or 10μm).

[0033] In one specific example, the negative electrode active material layer may include a negative electrode active material, such as at least one selected from graphite, mesophase microcarbon spheres (MCMB), hard carbon, soft carbon, silicon, silicon-carbon composites, spherical silicon-carbon, bulk silicon-carbon, Li-Al alloys, and metallic lithium. In embodiments where the negative electrode active material layer includes a silicon-carbon composite, the silicon content by mass fraction is 5%-50% (e.g., 5%, 5.5%, 8%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%).

[0034] In one specific example, the separator includes a base membrane and adhesive layers on both sides of the base membrane. In a further embodiment, a ceramic layer and an adhesive layer are sequentially formed on a first side of the base membrane, and an adhesive layer is formed on a second side. The first side surface of the base membrane is disposed opposite to the positive electrode, and the second side surface of the base membrane is disposed opposite to the negative electrode. In some embodiments, the thickness of the separator is 5 μm-20 μm (e.g., 5 μm, 8 μm, 10 μm, 13 μm, 15 μm, 18 μm, or 20 μm).

[0035] In one specific example, the battery also includes an electrolyte comprising a lithium salt and a solvent, wherein the solvent comprises at least one selected from ethylene carbonate, diethyl carbonate, or fluoroethylene carbonate. In another embodiment, the electrolyte further includes a nitrile additive. The nitrile additive comprises a C3 percentage based on the total mass of the electrolyte. C3 is 0.5%-8%, for example, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, or 8%. In some embodiments, the nitrile additive comprises, for example, at least one selected from butadionitrile, adiponitrile, and 1,3,6-hexanetrionitrile.

[0036] The battery cell 1 is disposed within the housing 2. The battery cell 1 includes a positive electrode 10 and a negative electrode 20. The negative electrode 20 is stacked with the positive electrode 10. In one example, the positive electrode 10, the separator 30, and the negative electrode 20 can be sequentially stacked to form a battery cell. Figure 5 (As shown). In another example, the positive electrode 10, the separator 30, the negative electrode 20, and the separator 30 can be wound and arranged in sequence to form a core.

[0037] The positive electrode 10 includes a positive current collector 11 and a positive active material layer 12 and an insulating layer 13 disposed on the surface of the positive current collector 11. The positive current collector 11 includes a positive electrode body 111 and a positive electrode tab 112. The positive active material layer 12 covers at least a portion of the surface of the positive electrode body 111, and the insulating layer 13 covers at least a portion of the surface of the positive electrode tab 112. Along the first direction X, the insulating layer 13 is connected to the first edge 12a of the positive active material layer 12, and the positive electrode tab 112 is connected to the second edge 111a of the positive electrode body 111.

[0038] The positive electrode body 111 is the main part of the positive current collector 11, and the positive electrode tab 112 is the part led out from one end of the positive electrode body 111. The positive electrode body 111 and the positive electrode tab 112 are an integral structural component. The first direction X is the direction in which the positive electrode tab 112 is led out (extended). The stacking direction Z of the positive electrode 10 and the negative electrode 20 is perpendicular to the first direction X.

[0039] The positive electrode active material layer 12 covering at least a portion of the surface of the positive electrode body 111 can be understood as the positive electrode active material layer 12 covering a portion of the surface of the positive electrode body 111. Figure 3 (As shown); it can also be understood that the positive electrode active material layer 12 covers the entire surface of the positive electrode body 111 and partially covers the surface of the positive electrode tab 112 (as shown). Figure 1 (As shown).

[0040] The negative electrode 20 includes a negative electrode current collector 21 and a negative electrode active material layer 22 disposed on the surface of the negative electrode current collector 21. The negative electrode current collector 21 includes a negative electrode body 211, and the surface of the negative electrode body 211 is provided with the negative electrode active material layer 22. The negative electrode body 211 covers the positive electrode body 111, i.e., the so-called "negative electrode covering positive electrode". The negative electrode body 211 includes a main region 2111 and a protruding region 2112. Along the first direction X, the protruding region 2112 protrudes from the main region 2111, such that the third edge 2112a of the protruding region 2112 extends beyond the fourth edge 2111a of the main region 2111.

[0041] The first edge 12a, the second edge 111a, the third edge 2112a, and the fourth edge 2111a are all located on the same side of the positive electrode tab 112 in the first direction X. The orthographic projection of the positive electrode tab 112 along the stacking direction Z at least partially overlaps with the orthographic projection of the protrusion 2112 along the stacking direction Z.

[0042] Reference Figure 1 Along the first direction X, the distance between the second edge 111a and the fourth edge 2111a is D, and the distance between the first edge 12a and the third edge 2112a is B, satisfying B≥D, 0.2mm≤B≤1.5mm, and 0.1mm≤D≤0.7mm. B can be any one or any combination of 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, and 1.5mm. D can be any one or any combination of 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, and 0.7mm.

[0043] The distance D between the fourth edge 2111a and the second edge 111a can be precisely controlled by cutting the positive electrode 10 and the negative electrode 20 during the manufacturing process, and the negative electrode 20 does not need to reserve any allowance. Since there are positional deviations during the coating of the insulating layer 13 and the positive electrode active material layer 12 on the surface of the positive electrode current collector 11, it is difficult to precisely control the distance B (i.e., the safe distance) between the first edge 12a and the third edge 2112a. By setting a negative electrode 20 with a protruding area 2112, that is, by increasing the local size of the negative electrode 20, a larger allowance is reserved for the above-mentioned positional deviation, ensuring the safe size of B. Compared with the previous method of reserving a allowance for the entire negative electrode 20, the waste of the negative electrode 20 can be reduced, and the mass energy density of the battery can be improved.

[0044] Since the size of B is relatively difficult to control compared to the size of D, B ≥ D ensures a safe size for B. A B greater than or equal to 0.2mm ensures a safe size for B, reduces the risk of lithium plating, and ensures the battery's cycle performance. However, if B is too large, it will lead to waste of the negative electrode 20, which is detrimental to improving the battery's mass energy density. Therefore, 0.2mm ≤ B ≤ 1.5mm is beneficial for ensuring a safe size for B, reducing the risk of lithium plating, ensuring the battery's cycle performance, and also for improving the battery's mass energy density.

[0045] A diameter (D) greater than or equal to 0.1 mm can reduce the risk of lithium plating and ensure the cycle performance of the battery; however, if D is too large, it will lead to waste of the negative electrode sheet 20, which is not conducive to improving the mass energy density of the battery; therefore, 0.1 mm ≤ D ≤ 0.7 mm can both reduce the risk of lithium plating and ensure the cycle performance of the battery, and is also conducive to improving the mass energy density of the battery.

[0046] In some embodiments, the distance between the third edge 2112a and the fourth edge 2111a is A, which satisfies 0.1mm≤A≤2mm. A can be any one of 0.1mm, 0.5mm, 0.7mm, 1mm, 1.5mm, 1.8mm, 2mm, or a value between any two of them.

[0047] If A is greater than 0.1mm, a larger margin can be reserved to ensure the safe size of B and reduce the risk of lithium plating. However, if A is too large, it will lead to waste of the negative electrode 20, which is not conducive to improving the mass energy density of the battery. Therefore, 0.1mm≤A≤2mm can both reduce the risk of lithium plating and improve the mass energy density of the battery.

[0048] In some embodiments, the negative electrode current collector 21 further includes a negative electrode tab 212, which is connected to the fourth edge 2111a of the main body region 2111. The negative electrode tab 212 and the negative electrode body 211 are integral structural components. Along the second direction Y, the distance between the negative electrode tab 212 and the protrusion region 2112 is G, which satisfies that G≥2mm, and the second direction Y, the first direction X, and the stacking direction Z are all perpendicular to each other.

[0049] Along the second direction Y, the distance G between the negative electrode tab 212 and the protruding area 2112 is too small, less than 2mm. This interferes with the bending process of the negative electrode tab 212, hindering the bending operation, reducing bending quality and manufacturing efficiency, and increasing the risk of breakage due to repeated friction at the bending point of the negative electrode tab 212 during battery cycling expansion. Therefore, G ≥ 2mm is required to provide more operational space for bending the negative electrode tab 212, improve bending quality, and reduce the risk of breakage caused by repeated friction at the bending point of the negative electrode tab 212 during battery cycling expansion.

[0050] In some embodiments, along the second direction Y, the two opposite edges of the protrusion 2112 extend beyond the opposite two sides of the positive electrode tab 112, and the extension dimension is E, satisfying E≥0.2mm.

[0051] Because the negative electrode 20 may be misaligned during manufacturing, if E is too small, less than 0.2mm, the protrusion area 2112 may not completely cover the positive electrode tab 112, eventually leading to lithium plating. Therefore, E ≥ 0.2mm is required to allow more margin for the misalignment of the negative electrode 20 and ensure that the protrusion area 2112 completely covers the positive electrode tab 112.

[0052] In some embodiments, refer to Figure 2The two sides of the protruding area 2112 at the corner are connected by an arc-shaped transition. This reduces stress concentration and prevents cracking. Alternatively, the two sides of the protruding area 2112 at the corner are connected by a rounded transition, with a radius R satisfying 0.5mm ≤ R ≤ 10mm. R can be any one of 0.5mm, 1mm, 1.5mm, 2.5mm, 5mm, 6.5mm, 7mm, 8mm, 9mm, and 10mm, or a value between any two of them.

[0053] Figure 2 The two corners of the protruding area 2112 are rounded. The internal corner is within the range of 0.5mm≤R≤10mm, which can avoid stress concentration on the electrode and prevent the electrode from cracking. The external corner is within the range of 0.5mm≤R≤10mm, which can prevent powder from falling off during electrode die-cutting.

[0054] In some embodiments, refer to Figure 4 Along the first direction X, the third edge 2112a of the protruding region 2112 is shortened from the fifth edge 13a of the insulating layer 13 on the positive electrode tab 112 and away from the positive electrode active material layer 12. The distance between the third edge 2112a and the fifth edge 13a is J, which satisfies that J≥0.7mm.

[0055] Typically, the positive electrode tab 112 is bent in the area with the insulating layer 13. The insulating layer 13 has a certain degree of elasticity and viscosity, which can reduce the risk of breakage during bending. In addition, during the charging and discharging process of the battery, lithium ions are inserted and extracted between the positive and negative electrodes, causing the electrode sheets to expand and contract. The insulating layer 13 can play a certain role in buffering and stress dispersion, reducing metal fatigue caused by repeated micro-movements at the bending position of the positive electrode tab 112, and reducing the risk of breakage of the positive electrode tab 112. If J is too small, less than 0.7 mm, the third edge 2112a of the protrusion area 2112 is too close to the fifth edge 13a of the positive electrode active material layer 12, leaving too little bending area for the positive electrode tab 112 in the insulating layer 13. This results in the bending position of the positive electrode tab 112 exceeding the insulating layer 13, leading to a high risk of breakage. Therefore, J needs to be ≥ 0.7 mm so that the insulating layer 13 of the positive electrode tab 112 has a sufficient bending area to reduce the risk of breakage.

[0056] In some embodiments, refer to Figure 1Along the first direction X, the positive electrode active material layer 12 extends to a portion of the surface of the positive electrode tab 112 and connects with the insulating layer 13. The edge connecting the positive electrode active material layer 12 and the insulating layer 13 on the positive electrode tab 112 is the first edge 12a. The distance between the first edge 12a and the second edge 111a is C1, satisfying 0 ≤ C1 ≤ 1.5 mm; or 0 ≤ C1 ≤ 0.5 mm, 0.1 mm ≤ A ≤ 1 mm. C1 can be any one or any two of 0, 0.5 mm, 0.6 mm, 0.8 mm, 0.9 mm, 1 mm, 1.2 mm, and 1.5 mm. A can be any one or any two of 0.1 mm, 0.3 mm, 0.6 mm, 0.8 mm, and 1 mm.

[0057] If C1 is too large, greater than 1.5 mm, the first edge 12a of the positive electrode active material layer 12 is too close to the third edge 2112a of the protrusion region 2112, resulting in a high risk of lithium plating. Therefore, controlling C1 within the range of 0 ≤ C1 ≤ 1.5 mm can reduce the risk of lithium plating.

[0058] The larger A is, the greater the safe distance between the first edge 12a of the positive electrode active material layer 12 and the third edge 2112a of the protrusion region 2112, and the lower the risk of lithium plating. However, if A is too large, greater than 1 mm, the margin of the protrusion region 2112 will be too large, causing unnecessary waste and reducing the mass energy density of the battery. Therefore, 0.1 mm ≤ A ≤ 1 mm can both reduce the risk of lithium plating and improve the mass energy density of the battery.

[0059] It is understandable that lithium plating can be reduced by controlling C1, or by controlling A. If C1 is controlled within 0 ≤ C1 ≤ 0.5 mm, the coating deviation of the positive electrode active material layer 12 and the insulating layer 13 will be smaller, which can further reduce the size of A, thereby helping to improve the mass energy density of the battery.

[0060] In some embodiments, refer to Figure 3 Along the first direction X, the insulating layer 13 extends to a portion of the surface of the positive electrode body 111 and connects with the positive electrode active material layer 12. The distance between the first edge 12a and the second edge 111a is C2, satisfying 0 ≤ C2 ≤ 1.5 mm; or 0 ≤ C2 ≤ 0.5 mm, 0.1 mm ≤ A ≤ 1 mm. C2 can be any one or any two of 0, 0.5 mm, 0.6 mm, 0.8 mm, 0.9 mm, 1 mm, 1.2 mm, and 1.5 mm. A can be any one or any two of 0.1 mm, 0.3 mm, 0.6 mm, 0.8 mm, and 1 mm.

[0061] and Figure 1The difference is that the positive electrode active material layer 12 extends onto the positive electrode tab 112. Figure 3 The positive electrode active material layer 12 does not extend to the positive electrode tab 112, but the insulating layer 13 extends to the positive electrode body 111.

[0062] If C2 is too large, greater than 1.5mm, the first edge 12a of the positive electrode active material layer 12 is too far from the third edge 2112a of the protrusion region 2112. The risk of lithium plating is low, but it will encroach on the coating area of ​​the positive electrode active material layer 12, resulting in low battery mass energy density. Therefore, controlling C2 within the range of 0≤C1≤1.5mm can reduce the risk of lithium plating and also help improve the battery mass energy density.

[0063] The larger A is, the greater the safe distance between the first edge 12a of the positive electrode active material layer 12 and the third edge 2112a of the protrusion region 2112, and the lower the risk of lithium plating. However, if A is too large, greater than 1 mm, the margin of the protrusion region 2112 will be too large, causing unnecessary waste and reducing the mass energy density of the battery. Therefore, 0.1 mm ≤ A ≤ 1 mm can both reduce the risk of lithium plating and improve the mass energy density of the battery.

[0064] It is understandable that lithium plating can be reduced by controlling C2, or by controlling A. If C2 is controlled within the range of 0 ≤ C2 ≤ 0.5 mm, the coating deviation of the positive electrode active material layer 12 and the insulating layer 13 will be smaller, which can further reduce the size of A, thereby helping to improve the mass energy density of the battery.

[0065] In some embodiments, refer to Figure 4 Along the first direction X, the distance between the third edge 2112a of the protruding area 2112 and the inner wall of the outer shell 2 is P1, which satisfies 1mm≤P1≤3mm. P1 can be any one of 1mm, 1.5mm, 1.8mm, 2mm, 2.5mm, 3mm, or any combination thereof. The outer shell 2 can be a cuboid shell.

[0066] If P1 is too small, the protrusion size of the protrusion area 2112 will be large, resulting in a large margin for the negative electrode 20, which is not conducive to the battery's mass energy density; if P1 is too large, the space utilization rate will be low, which is not conducive to improving the battery's volumetric energy density. Therefore, 1mm≤P1≤3mm is beneficial to both improving the battery's mass energy density and improving the battery's volumetric energy density.

[0067] In some embodiments, along the first direction X, the distance between the fourth edge 2111a and the inner wall of the outer shell 2 is P2, which satisfies 1.2mm≤P2≤4mm. P2 can be any one of 1.2mm, 1.5mm, 1.8mm, 2mm, 2.5mm, 3mm, 4mm, or any value between any two of them.

[0068] If P2 is too small, the negative electrode body 211 will exceed the positive electrode body 111 by a large margin, resulting in a large margin for the negative electrode 20, which is not conducive to the battery's mass energy density. If P2 is too large, the space utilization rate will be low, which is not conducive to improving the battery's volumetric energy density. Therefore, 1.2mm≤P2≤4mm is beneficial to improving both the battery's mass energy density and volumetric energy density.

[0069] In some embodiments, the outer shell 2 includes a shell body portion 201 and a protruding portion 202. Along a first direction X, the protruding portion 202 protrudes from the shell body portion 201, and the protruding portion 202 corresponds to a protruding area 2112. Along the first direction X, the distance between the third edge 2112a of the protruding area 2112 and the inner wall of the protruding portion 202 is P3, the distance between the fourth edge 2111a and the inner wall of the shell body portion 201 is P4, and the distance between the outer wall of the shell body portion 201 and the outer wall of the protruding portion 202 is H, satisfying that P3 ≥ P4, 1 mm ≤ P3 ≤ 3 mm, 0.6 mm ≤ P4 ≤ 3 mm, and 0.1 mm ≤ H ≤ 5 mm. P3 can be any one or any combination of 1 mm, 1.3 mm, 1.6 mm, 2 mm, 2.5 mm, and 3 mm. P4 can be any one of 0.6mm, 1.3mm, 1.6mm, 2mm, 2.5mm, 3mm, or any value between any two of them. H can be any one of 0.1mm, 1mm, 2mm, 3mm, 4mm, 5mm, or any value between any two of them.

[0070] The outer shell 2 is irregularly shaped, and its structure matches the structure of the cell 1. By P3≥P4, the space between the negative electrode body 211 and the shell body 201 is reduced, which is beneficial to improving the volumetric energy density when the battery is assembled.

[0071] If P3 is too small, the protrusion size of the protrusion area 2112 will be large, resulting in a large margin for the negative electrode 20, which is not conducive to the battery's mass energy density; if P3 is too large, the space utilization rate will be low, which is not conducive to improving the battery's volumetric energy density. Therefore, 1mm≤P3≤3mm is beneficial to improving both the battery's mass energy density and the battery's volumetric energy density.

[0072] If P4 is too small, the negative electrode body 211 will exceed the positive electrode body 111 by a large margin, resulting in a large margin for the negative electrode 20, which is not conducive to the battery's mass energy density. If P4 is too large, the space utilization rate will be low, which is not conducive to improving the battery's volumetric energy density. Therefore, 0.6mm≤P4≤3mm is beneficial to improving both the battery's mass energy density and volumetric energy density.

[0073] If H is too small, the space between the negative electrode body 211 and the shell body 201 is too large, resulting in low space utilization and hindering the improvement of battery volumetric energy density; if H is too large, the volumetric energy density of the battery pack is low. Therefore, 0.1mm≤H≤5mm is beneficial for both improving the battery volumetric energy density and improving the volumetric energy density of the battery pack.

[0074] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application, are intended to cover non-exclusive inclusion. In the description of embodiments of this application, technical terms such as "first," "second," etc., are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of embodiments of this application, "a plurality of" means two or more, unless otherwise expressly and specifically defined. The reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0075] In the description of the embodiments of this application, the technical terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "circumferential," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed, operated, or used in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0076] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" 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. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0077] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery, characterized in that, Includes a battery cell (1) and a housing (2), wherein the battery cell (1) is disposed within the housing (2), and the battery cell (1) comprises: A positive electrode sheet (10) includes a positive current collector (11) and a positive active material layer (12) and an insulating layer (13) disposed on the surface of the positive current collector (11). The positive current collector (11) includes a positive electrode sheet body (111) and a positive electrode tab (112). The positive active material layer (12) covers at least a portion of the surface of the positive electrode sheet body (111), and the insulating layer (13) covers at least a portion of the surface of the positive electrode tab (112). Along a first direction (X), the insulating layer (13) is connected to a first edge (12a) of the positive active material layer (12), and the positive electrode tab (112) is connected to a second edge (111a) of the positive electrode sheet body (111). A negative electrode (20) is stacked with the positive electrode (10). The negative electrode (20) includes a negative current collector (21) and a negative active material layer (22) disposed on the surface of the negative current collector (21). The negative current collector (21) includes a negative electrode body (211), and the negative active material layer (22) is disposed on the surface of the negative electrode body (211). The negative electrode body (211) includes a main body region (2111) and a protruding region (2112). Along a first direction (X), the protruding region (2112) protrudes. In the main body region (2111), the third edge (2112a) of the protruding region (2112) extends beyond the fourth edge (2111a) of the main body region (2111). The first edge (12a), the second edge (111a), the third edge (2112a), and the fourth edge (2111a) are all located on the same side of the positive electrode tab (112) in the first direction (X). The stacking direction (Z) of the positive electrode sheet (10) and the negative electrode sheet (20) is perpendicular to the first direction (X). The orthographic projection of the positive electrode tab (112) along the stacking direction (Z) at least partially overlaps with the orthographic projection of the protrusion area (2112) along the stacking direction (Z); Along the first direction (X), the distance between the second edge (111a) and the fourth edge (2111a) is D, and the distance between the first edge (12a) and the third edge (2112a) is B, satisfying that B≥D, 0.2mm≤B≤1.5mm, and 0.1mm≤D≤0.7mm.

2. The battery according to claim 1, characterized in that, The distance between the third edge (2112a) and the fourth edge (2111a) is A, which satisfies 0.1mm≤A≤2mm.

3. The battery according to claim 1, characterized in that, The negative current collector (21) also includes a negative electrode tab (212), which is connected to the fourth edge (2111a) of the main body region (2111). Along the second direction (Y), the distance between the negative electrode tab (212) and the protruding area (2112) is G, which satisfies that G≥2mm, and the second direction (Y), the first direction (X) and the stacking direction (Z) are perpendicular to each other; and / or, along the second direction (Y), the two opposite edges of the protruding area (2112) extend beyond the opposite two sides of the positive electrode tab (112) by a dimension E, which satisfies that E≥0.2mm.

4. The battery according to claim 1, characterized in that, The protruding area (2112) is located at the corner where the two sides are connected by an arc-shaped transition; or, The protruding area (2112) is connected by rounded corners at the corner position. The radius of the rounded corner is R, which satisfies 0.5mm≤R≤10mm.

5. The battery according to claim 1, characterized in that, Along the first direction (X), the third edge (2112a) of the protruding area (2112) is shortened from the fifth edge (13a) of the insulating layer (13) on the positive electrode tab (112) away from the positive electrode active material layer (12), and the distance between the third edge (2112a) and the fifth edge (13a) is J, which satisfies J≥0.7mm.

6. The battery according to any one of claims 1-5, characterized in that, Along the first direction (X), the positive electrode active material layer (12) extends to a portion of the surface of the positive electrode tab (112) and connects with the insulating layer (13). The edge where the positive electrode active material layer (12) on the positive electrode tab (112) connects with the insulating layer (13) is the first edge (12a). The distance between the first edge (12a) and the second edge (111a) is C1, which satisfies that 0≤C1≤1.5mm; or 0≤C1≤0.5mm, 0.1mm≤A≤1mm.

7. The battery according to any one of claims 1-5, characterized in that, Along the first direction (X), the insulating layer (13) extends to a portion of the surface of the positive electrode body (111) and is connected to the positive electrode active material layer (12). The distance between the first edge (12a) and the second edge (111a) is C2, which satisfies that 0≤C2≤1.5mm; or 0≤C2≤0.5mm, 0.1mm≤A≤1mm.

8. The battery according to any one of claims 1-5, characterized in that, Along the first direction (X), the distance between the third edge (2112a) of the protruding area (2112) and the inner wall of the outer shell (2) is P1, satisfying 1mm≤P1≤3mm; and / or, along the first direction (X), the distance between the fourth edge (2111a) and the inner wall of the outer shell (2) is P2, satisfying 1.2mm≤P2≤4mm.

9. The battery according to any one of claims 1-5, characterized in that, The outer shell (2) includes a shell body portion (201) and a protruding portion (202). Along the first direction (X), the protruding portion (202) protrudes from the shell body portion (201) and corresponds to the protruding area (2112). Along the first direction (X), the distance between the third edge (2112a) of the protruding area (2112) and the inner wall of the protruding portion (202) is P3, the distance between the fourth edge (2111a) and the inner wall of the shell body portion (201) is P4, and the distance between the outer wall of the shell body portion (201) and the outer wall of the protruding portion (202) is H, satisfying that P3≥P4, 1mm≤P3≤3mm, 0.6mm≤P4≤3mm, and 0.1mm≤H≤5mm.

10. The battery according to any one of claims 1-5, characterized in that, The outer casing is a metal casing or an aluminum-plastic film; and / or, The battery cell (1) has a stacked structure, and the battery cell (1) also includes a separator (30) disposed between the positive electrode (10) and the negative electrode (20).

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