Batteries and power-using equipment

Abstract

The present invention discloses a battery and an electrical equipment. The battery includes an electrode sheet including a fluid collector and an active material layer provided on the fluid collector, and a tab connected to the fluid collector and protruding from the electrode sheet along the width direction of the electrode sheet. Along the width direction of the electrode sheet, the tab includes a first region and a second region, the first region is located between the second region and the active material layer, the first region has a thickness t1, the second region has a thickness t2, and 0.5%≦(t1-t2) / t1≦5%.

Description

[Technical Field]

[0001] The present invention relates to the technical field of energy storage, and in particular to batteries and power-using equipment. [Background technology]

[0002] Currently, the production process of battery electrode sheets typically involves coating and cold pressing. Cold pressing, which consolidates the electrode sheet, plays a crucial role in improving the energy density and electrical performance of batteries. The active material layer region and the blank foil region forming the tab undergo different degrees of elongation during the cold pressing process. Therefore, to reduce the risk of deformation or warpage of the tab after cold rolling, the blank foil region typically needs to be stretched. However, this stretching process is prone to breakage of the electrode sheet, affecting the yield of cold pressing. To mitigate the risk of electrode sheet breakage, conventional techniques typically use thicker current collectors or reduce the compaction density of the electrode sheet. However, these measures are not only less effective in reducing the breakage phenomenon, but also result in a loss of energy density. Summary of the Invention [Problem to be solved by the invention]

[0003] In view of the above circumstances, it is necessary to provide a battery that can reduce the risk of electrode sheet breakage and improve the energy density of the battery. [Means for solving the problem]

[0004] A battery according to an embodiment of the present application includes an electrode sheet and a tab, the electrode sheet including a fluid collector and an active material layer disposed on the fluid collector, the tab being connected to the fluid collector and protruding from the electrode sheet along the width direction of the electrode sheet, the tab including a first region and a second region along the width direction of the electrode sheet, the first region being located between the second region and the active material layer, the first region having a thickness t1, the second region having a thickness t2, and 0.5%≦(t1-t2) / t1≦5%.

[0005] In the above battery, tabs are installed in the first and second regions along the width direction of the electrode sheet, with the first region positioned between the second region and the active material layer. The second region is pre-rolled and stretched before cold rolling. The thickness t1 of the first region and the thickness t2 of the second region satisfy the relationship 0.5%≦(t1-t2) / t1≦5%, and the difference between the thicknesses of the first and second regions is not too large. If the difference is too large, stress will concentrate at the boundary, making the electrode sheet prone to tearing. If the difference is too small, less than 0.5%, the second region will not achieve the desired elongation effect, and the tabs will likely warp or bend. Therefore, satisfying the relationship 0.5%≦(t1-t2) / t1≦5% reduces the risk of electrode sheet tearing after cold rolling and improves the yield rate. Furthermore, thinner collectors and / or higher compaction density structures can be employed, thereby increasing the energy density of the battery.

[0006] In some embodiments of the present application, 0.5%≦(t1−t2) / t1≦3%, which can further reduce the phenomenon in which the electrode sheet breaks after cold rolling.

[0007] In some embodiments of the present application, 0.5%≦(t1−t2) / t1≦1.5%, which can further reduce the phenomenon in which the electrode sheet breaks after cold rolling.

[0008] In some embodiments of the present application, the electrode sheet undergoes a cold-rolling process during production. After cold-rolling, the fluid-collecting region coated with the active material layer exhibits good extensibility, while the second region exhibits good extensibility after pre-rolling. Because the first region is adjacent to the active material layer and cannot be rolled during the process, it exhibits poor extensibility. During the electrode sheet winding process, the first region is interposed between the active material layer and the second region, causing the electrode sheet to arch in the second region, resulting in warping or bending of the electrode sheet. Therefore, the area of the first region is generally minimized and the area of the second region is maximized. Thus, along the thickness direction of the tab, the projected area of the tab is S1, and the projected area of the second region is S2, with 60%≦S2 / S1≦95%, which is advantageous for reducing warping and bending of the tab and improving the yield rate of the winding process, the flatness of the battery cell, and the energy density.

[0009] In some embodiments of the present application, 80%≦S2 / S1≦95%, which further reduces the occurrence of defects such as warpage and bending of the tab after cold rolling, and can increase the yield of non-defective winding, flatness of the battery cell, and energy density.

[0010] In some embodiments of the present application, the tab is provided between the first region and the active material layer and further includes a third region connecting the first region and the active material layer. A first insulating layer is provided in the third region, and the first insulating layer is located between the first region and the active material layer. The first insulating layer provides insulation when the electrode sheets are wound or stacked to form an electrode assembly, and can reduce the risk of short-circuiting between this tab and other tabs / electrode sheets of opposite polarity due to burrs puncturing the separator.

[0011] In some embodiments of the present application, a first boundary line is further present at the boundary between the first region and the second region. The minimum distance between the first boundary line and the first insulating layer is d1, and 0.1 mm≦d1≦1 mm is satisfied, so that the first region has a constant width along the width direction of the electrode sheet. The first region serves as a transition region between the pre-rolled and stretched second region and the active material layer, improving the structural strength of the connection region between the first tab and the active material layer and reducing the risk of bending or breaking of the first tab along the connection point with the active material layer, thereby improving the earthquake resistance of the battery.

[0012] In some embodiments of the present application, the first insulating layer satisfies at least one of the following conditions a, b, and c: a) The thickness of the first insulating layer is smaller than the thickness of the active material layer. b. The length of the tab along the width direction of the electrode sheet is W1, the length of the first insulating layer is W2, and W2 / W1≦0.5 and W2≧1 mm. c) The first insulating layer includes an inorganic material, and the inorganic material includes at least one of aluminum oxide, magnesium oxide, and titanium oxide.

[0013] In some embodiments of the present application, the number of tabs is plural.

[0014] In some embodiments of the present application, the tab is a positive electrode tab.

[0015] An embodiment of the present application also provides an electrical appliance including the battery according to any of the above aspects.

[0016] In the above-mentioned electrical equipment, the battery has tabs installed in the first and second regions, and is rolled in the second region to pre-stretch the second region, thereby reducing the phenomenon of the electrode sheet breaking after cold rolling, and further allowing for a thinner fluid-collecting structure and / or a higher compaction density, thereby improving the energy density of the battery. [Brief explanation of the drawings]

[0017] [Figure 1]1 is a schematic diagram of a three-dimensional structure of a battery according to an embodiment of the present application. [Figure 2] FIG. 1 is a schematic diagram of a battery in an embodiment of the present application before packaging. [Figure 3] 3 is a cross-sectional view of the electrode assembly in FIG. 2 taken along line III-III. [Figure 4] 1 is a schematic diagram of a structure in which a first tab is connected to a first electrode sheet in an embodiment of the present application. [Figure 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 5 is a configuration diagram of an expanded embodiment of the configuration shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 5 is a configuration diagram of an expanded embodiment of the configuration shown in FIG. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8. [Figure 10] FIG. 5 is a configuration diagram of an expanded embodiment of the configuration shown in FIG. [Figure 11] FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. [Figure 12] FIG. 5 is a configuration diagram of an expanded embodiment of the configuration shown in FIG. [Figure 13] FIG. 2 is a schematic diagram of a structure in which a second tab is connected to a second electrode sheet in an embodiment of the present application. [Figure 14] FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. [Figure 15] 1 is a configuration diagram of an electricity-using facility according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following specific embodiments will explain the present invention in detail based on the above-mentioned drawings. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, technical aspects of the embodiments of the present application will be described with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments.

[0019] It should be noted that when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be an intermediary between them. Also, when a component is considered to be "attached" to another component, it may be directly "attached" to the other component or there may be an intermediary between them.

[0020] 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. The terminology used in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0021] Currently, the production process of battery electrode sheets typically involves coating and cold pressing. Cold pressing, which consolidates the electrode sheet, plays a crucial role in improving the energy density and electrical performance of batteries. The active material layer region and the blank foil region forming the tab undergo different degrees of elongation during the cold pressing process. Therefore, after the electrode sheet undergoes cold rolling, the blank foil region typically needs to be stretched to reduce the risk of deformation or warpage of the tab. However, this stretching process is prone to breakage of the electrode sheet, affecting the yield of cold pressing. To mitigate the risk of electrode sheet breakage, conventional techniques typically use thicker current collectors or reduce the compaction density of the electrode sheet. However, these measures are not only less effective in reducing the breakage phenomenon, but also result in a loss of energy density.

[0022] According to an embodiment of the present invention, a battery includes an electrode sheet and a tab, the electrode sheet includes a fluid collector and an active material layer disposed on the fluid collector, the tab is connected to the fluid collector and protrudes from the electrode sheet along the width direction of the electrode sheet, the tab includes a first region and a second region along the width direction of the electrode sheet, the first region is located between the second region and the active material layer, the thickness of the first region is t1, the thickness of the second region is t2, and 0.5%≦(t1-t2) / t1≦5%.

[0023] In the battery described above, the tabs are provided in the first and second regions along the width direction of the electrode sheet, with the first region positioned between the second region and the active material layer. The second region is pre-stretched by rolling, so that the thickness t1 of the first region and the thickness t2 of the second region satisfy 0.5%≦(t1-t2) / t1≦5%. The difference in thickness between the first and second regions must not be too large. If the difference is too large, stress concentrates at the boundary, making the electrode sheet prone to tearing. If the difference is too small, less than 0.5%, the second region does not achieve the stretching effect, making the tab prone to warping or bending. Therefore, by having the thickness t1 of the first region and the thickness t2 of the second region satisfy 0.5%≦(t1-t2) / t1≦5%, the phenomenon of the electrode sheet breaking after cold pressing can be reduced. The difference in thickness between the first and second regions cannot be too large; if it is too large, stress will concentrate at the boundary, making the tab more likely to break; if it is too small, the second region will not achieve the desired stretching effect, making the tab more likely to warp or bend.

[0024] Hereinafter, the embodiments of the present application will be further described with reference to the drawings.

[0025] 1, 2, and 3, one embodiment of the present application provides a battery 100 including a housing 10, an electrode assembly 20, a first tab 30, and a second tab 40. The electrode assembly 20 is provided inside the housing 10. The first tab 30 and the second tab 40 are both connected to the electrode assembly 20 and protrude from the housing 10.

[0026] In one embodiment, the housing 10 has a first part 11 and a second part 12 that are interconnected, and the first part 11 and the second part 12 are connected opposite each other to form an internal space that can accommodate the electrode assembly 20.

[0027] In one embodiment, the housing 10 includes a body portion 13 and a rim portion 14. The rim portion 14 is connected to and extends from the body portion 13. The electrode assembly 20 is disposed within the body portion 13. A first tab 30 and a second tab 40 extend from the rim portion 14. In one embodiment, the rim portion 14 includes a top seal 141 and a side seal 142 that are connected to each other. The first tab 30 and the second tab 40 extend from the top seal 141.

[0028] In one embodiment, the first tab 30 and the second tab 40 are located on the same side of the main body portion 13. In other embodiments, the first tab 30 and the second tab 40 may be located on opposite ends (not shown) of the main body portion 13.

[0029] The electrode assembly 20 includes a first electrode sheet 21, a second electrode sheet 22, and a separator 23. The separator 23 is disposed between the first electrode sheet 21 and the second electrode sheet 22. The first electrode sheet 21, the separator 23, and the second electrode sheet 22 are wound together to form the electrode assembly 20. A first tab 30 is connected to the first electrode sheet 21, and a second tab 40 is connected to the second electrode sheet 22. In another embodiment, the first electrode sheet 21, the separator 23, and the second electrode sheet 22 are stacked to form the electrode assembly 20 (not shown).

[0030] One of the first tab 30 and the second tab 40 is a positive electrode tab, and the other of the first tab 30 and the second tab 40 is a negative electrode tab. In one embodiment, the first tab 30 is a positive electrode tab, the second tab 40 is a negative electrode tab, the first electrode sheet 21 is a positive electrode sheet, and the second electrode sheet 22 is a negative electrode sheet. In one embodiment, the material of the first tab 30 includes aluminum. In one embodiment, the material of the second tab 40 includes any of copper, nickel, and a nickel alloy.

[0031] 4 and 5, the first electrode sheet 21 includes a first current collector 211 and a first active material layer 212 provided on the surface of the first current collector 211. The first tab 30 is connected to the first current collector 211 and protrudes from the first electrode sheet 21 along a first direction Z. Here, the first direction Z is the width direction of the first electrode sheet 21.

[0032] In the present embodiment, the first tab 30 and the first current collector 211 are an integrally molded structure, and the first tab 30 is cut out from the first current collector 211. In one embodiment, the material of the first current collector 211 includes aluminum.

[0033] The first electrode sheet 21 is provided with a first active material layer 212, which is also called a coating region. The region where the first fluid collecting layer 211 is exposed on the first electrode sheet 21 and the region where the first fluid collecting layer 211 is exposed on the first tab 30 are also called blank regions.

[0034] To increase the compaction density of the first active material layer 212 and the energy density of the battery 100, the first electrode sheet 21 must be cold-rolled before the first current collector 211 on the first electrode sheet 21 forms the first tab 30. During cold-rolling, some particles of the first active material layer 212 are pressed into the first current collector 211, reducing the structural strength and stretchability of the first current collector 211. When stretching the hollow foil region after cold-rolling, the first current collector 211 is likely to break, affecting the yield rate of the processing. In the first electrode sheet 21 provided herein, at least a portion of the hollow foil region is pre-rolled and stretched before cold-rolling. After cutting the first current collector 211 to form the first tab 30, the pre-rolled and stretched hollow foil region forms at least a portion of the first tab 30.

[0035] The first tab 30 includes a first region 31 and a second region 32. The first region 31 is located between the second region 32 and the first active material layer 212, and connects the second region 32 and the first electrode sheet 21.

[0036] The first tab 30 has a first boundary line 34 located at the boundary between the first region 31 and the second region 32. The first region 31 and the second region 32 are located on either side of the first boundary line 34 along the first direction Z.

[0037] In the present invention, the first boundary line 34 is formed by pre-rolling and developing the first electrode sheet 21, and the pre-rolled and developed blank foil region constitutes the second region 32. In one embodiment, the first boundary line 34 is a pressing mark.

[0038] Along a second direction X perpendicular to the first direction Z, the first region 31 has a thickness t1, the second region 32 has a thickness t2, and 0.5%≦(t1−t2) / t1≦5%. Here, the second direction X is the thickness direction of the first electrode sheet 21.

[0039] In the battery 100 of the present invention, before cold-rolling the first electrode sheet 21, a portion of the blank foil region is rolled and pre-stretched, so that the thickness t1 of the first region 31 (not pre-stretched) and the thickness t2 of the second region 32 (pre-stretched) satisfy the relationship 0.5%≦(t1-t2) / t1≦5%. The difference in thickness between the first region and the second region must not be too large. If the difference is too large, stress will concentrate at the boundary, making the electrode sheet prone to fracture. If the difference is too small, less than 0.5%, the second region 32 will not exhibit the stretching effect, and the first tab 30 will be prone to warping and bending. After the first electrode sheet 21 of the present application is cold-rolled, the thickness t1 of the first region 31 and the thickness t2 of the second region 32 satisfy 0.5%≦(t1−t2) / t1≦5%, and the first electrode sheet 21 provided in the present application can reduce the breakage phenomenon compared to other first electrode sheets 21 in which the hollow foil region is stretched after cold-rolling. Furthermore, the first electrode sheet 21 of the present application can employ a thinner first current collector 211 and a first active material layer 212 with a higher compaction density while ensuring that the frequency of breakage does not increase, thereby increasing the energy density of the battery 100.

[0040] In one embodiment, 0.5%≦(t1-t2) / t1≦3%, which can further reduce the fracture phenomenon of the first electrode sheet 21, and further, a thinner fluid-collecting structure and / or a higher compaction density structure can be adopted to improve the energy density of the battery.

[0041] In one embodiment, 0.5%≦(t1−t2) / t1≦1.5%, which can further reduce the breakage phenomenon of the first electrode sheet 21. In one embodiment, the value of (t1−t2) / t1 is any one of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, and 5%.

[0042] In one embodiment, the projection area of the first tab 30 along the second direction X is S1, and the projection area of the second region 32 is S2, where 60%≦S2 / S1≦95%. Because the first region 31 has relatively poor extensibility and the second region 32 has relatively good extensibility after pre-rolling, if the area of the second region 32 is too small, warping and bending will easily occur during the winding process of the first electrode sheet 21. Therefore, the projection area S1 of the first tab 30 and the projection area S2 of the second region 32 along the thickness direction of the first tab 30 satisfy the ratio 60%≦S2 / S1≦95%. This is advantageous for reducing warping and bending of the first tab 30 and improving the flatness and energy density of the battery cell.

[0043] In one embodiment, the condition of 80%≦S2 / S1≦95% can further reduce the warping or bending of the first tab 30, and improve the flatness and energy density of the battery cell.

[0044] In one embodiment, the value of S2 / S1 is one of 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% and 100%.

[0045] As shown in Figures 6 and 7, in one embodiment, the first tab 30 further includes a third region 33 located between the first region 31 and the first active material layer 212, and the third region 33 connects the first region 31 and the first active material layer 212.

[0046] In one embodiment, the first tab 30 further has a second boundary line 35 located at the boundary between the first region 31 and the third region 33, and along the first direction Z, the first region 31 and the third region 33 are located on both sides of the second boundary line 35, respectively.

[0047] The battery 100 further includes a first insulating layer 50 disposed on the surface of the third region 33, the first insulating layer 50 being connected to the first active material layer 212. When the first electrode sheet 21, the second electrode sheet 22, and the separator 23 are wound or stacked to form the electrode assembly 20, the first insulating layer 50 provides insulating protection, reducing the risk of short-circuiting between the first tab 30 and the second tab 40 and improving the safety performance of the battery 100. Compared to a battery 100 without the first insulating layer 50, burrs on the edge of the first tab 30 are more likely to pierce the separator 23 and electrically connect with the second tab 40, causing a short circuit in the battery. In one embodiment of the present application, the first insulating layer 50 covers the burrs on the edge of the first tab 30, thereby reducing the risk of short-circuiting in the battery 100.

[0048] In one embodiment, the first active material layer 212 completely covers the first current collector 211 of the first electrode sheet 21, and the first insulating layer 50 is connected to the first active material layer 212 to reduce the exposed area of the blank foil region, further reducing the risk of short-circuiting between the first tab 30 and the second tab 40, and improving the safety of the battery 100.

[0049] 8 and 9 , in one embodiment, the first electrode sheet 21 is provided with a fourth region 213, in which the first current collector 211 is exposed, and which is located between the first active material layer 212 and the first tab 30 to connect the first active material layer 212 and the first tab 30. In one embodiment, the fourth region 213 is located between the first active material layer 212 and the third region 33 to connect the first active material layer 212 and the third region 33.

[0050] The battery 100 further includes a second insulating layer 60 disposed on the surface of the fourth region 213. The second insulating layer 60 connects the first insulating layer 50 and the first active material layer 212. When the first electrode sheet 21, the second electrode sheet 22, and the separator 23 are wound or stacked to form the electrode assembly 20, the second insulating layer 60 serves as an insulator, reducing the risk of short-circuiting between the first electrode sheet 21 and the second electrode sheet 22 and improving the safety performance of the battery 100. Compared to a battery 100 without the second insulating layer 60, the burrs on the edge of the first electrode sheet 21 are more likely to pierce the separator 23 and become electrically connected to the second electrode sheet 22, resulting in a short circuit in the battery 100. In one embodiment of the present application, the second insulating layer 60 covers the burrs on the edge of the first electrode sheet 21, further reducing the risk of short-circuiting in the battery 100.

[0051] As shown in Figures 10 and 11, in one embodiment, the first insulating layer 50 and the second insulating layer 60 are made of the same material, and the first insulating layer 50 and the second insulating layer 60 are formed in one step, which simplifies the manufacturing process of the battery 100, shortens the manufacturing cycle of the battery 100, and saves costs.

[0052] For ease of understanding and explanation, the following will further explain, by way of example, a case in which the first insulating layer 50 is provided on the surfaces of both the third region 33 and the fourth region 213.

[0053] In one embodiment, a first boundary line 34 is further provided along the first direction Z at the boundary between the first region 31 and the second region 32, and the minimum distance between the first boundary line 34 and the first insulating layer 50 is d1, where 0.1 mm≦d1≦1 mm, so that the first region 31 has a constant width along the first direction Z. The first region 31 can be a transition region between the pre-rolled second region 32 and the first tab 30, which enhances the structural strength of the connection region between the first tab 30 and the first electrode sheet 21, reduces the risk of the first tab 30 bending or breaking along the connection point with the first tab 21, and improves the earthquake resistance of the battery 100.

[0054] In one embodiment, 0.4 mm ≤ d1 ≤ 1 mm, which further ensures the structural strength of the connection region between the first pole tab 30 and the first electrode sheet 21, reduces the risk that the first tab 30 bends or breaks along the connection location with the first electrode sheet 21, and can improve the seismic performance of the battery 100.

[0055] In one embodiment, the value of d1 is any one of 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, and 1 mm.

[0056] In one embodiment, along the second direction X, the thickness of the first insulating layer 50 is t3, the thickness of the first active material layer 212 is t4, and t3 < t4. In one embodiment, 50 μm ≤ t4 ≤ 150 μm.

[0057] In other embodiments, t3 = t4 (not shown). In other embodiments, t3 > t4 (not shown).

[0058] In one embodiment, along the first direction Z, the length of the first insulating layer 50 is W2, W2 ≥ 1 mm, and the length range of the first insulating layer 50 along the first direction Z can guarantee the protection effect of the first insulating layer 50 and reduce the risk that the battery 100 is short-circuited. In one embodiment, W2 ≥ 2 mm.

[0059] In one embodiment, along the first direction Z, the length of the first tab 30 is W1, W2 / W1 ≤ 0.5, and the dimensional relationship along the first direction Z between the first tab 30 and the first insulating layer 50 is advantageous for enhancing the current conduction ability and heat dissipation ability of the first tab 30 and for enhancing the charge and discharge speed and heat dissipation efficiency of the battery 100.

[0060] In one embodiment, the first insulating layer 50 contains an inorganic substance. In one embodiment, the material of the inorganic substance includes, but is not limited to, at least one of alumina, magnesia, and titanium oxide.

[0061] In one embodiment, the weight of the first active material layer 212 is G1, 100 g / m2 ≦G1≦300g / m 2 Here, the weight G1 of the first active material layer 212 refers to the weight of the first active material layer 212 applied to one surface of the first current collector 211 per square meter.

[0062] In one embodiment, the first active material layer 212 has a compaction density D1 of 2.2 g / m 3 ≦D1≦4.2g / m 3 The compaction density D1 of the first active material layer 212 refers to the weight of the first active material layer 212 per unit volume after the first electrode sheet 21 has been cold-rolled.

[0063] 12 , in one embodiment, the number of first tabs 30 is multiple, and the multiple first tabs 30 are spaced apart along a third direction Y perpendicular to the first direction Z and the second direction X. Providing multiple first tabs 30 can improve not only the charge / discharge speed of the battery 100 but also the heat dissipation capability of the battery 100. Optionally, the number of first tabs 30 is two.

[0064] 13 and 14, the second electrode sheet 22 includes a second fluid collector 221 and a second active material layer 222 provided on the surface of the second fluid collector 221. The second electrode sheet 40 is connected to the second fluid collector 221 and extends from the second electrode sheet 22 along the first direction Z.

[0065] In one embodiment, the second tab 40 and the second current collector 221 are an integrally formed structure, and the second tab 40 is cut by the second current collector 221. In one embodiment, the material of the second current collector 221 includes any of copper, nickel, and nickel alloy.

[0066] The second tab 40 and the second collector 221 have a higher structural strength and a stronger ability to resist deformation than the first tab 30 and the first collector 211. In one embodiment, the second electrode sheet 22 does not need to be stretched and unfolded for the blank foil region after being cold pressed. In one embodiment, the second electrode sheet 22 does not need a pre-rolling operation for the blank foil region before cold rolling.

[0067] In one embodiment, the second electrode sheet 22 is subjected to a pre-rolling operation on the uncoated blank foil region of the second electrode sheet 22 before cold rolling, thereby reducing the occurrence of breakage in the second electrode sheet 22 after cold rolling. In one embodiment, the pre-rolling operation on the blank foil region of the second electrode sheet 22 is similar to any of the pre-rolling operations on the blank foil region of the first electrode sheet 21, and will not be further described in this application.

[0068] In one embodiment, the manufacturing flow of the first electrode sheet 21 is as follows. (1) 96% lithium cobalt oxide, 1.5% conductive carbon, 2.5% binder, and an appropriate amount of solvent (e.g., deionized water, N-methylpyrrolidone) are uniformly mixed to prepare a slurry with a solid content of about 75%. (2) The slurry of step (1) is applied to a portion of the surface of the first collected fluid 211, and a portion of the surface of the first collected fluid 211 is exposed. (3) The slurry on the surface of the first current collector 211 in step (2) is dried to obtain the first electrode sheet 21. (4) The exposed blank foil region of the first electrode sheet 21 obtained in step (3) is rolled and developed in advance, and then the coated region of the first electrode sheet 21 is roll-pressed to obtain the first electrode sheet 21.

[0069] In one embodiment, the manufacturing flow of the first tab 30 is to cut the blank foil area of the first tab 21 described above to obtain the first tab 30 protruding from the first tab 21.

[0070] The above-described manufacturing flow and process of the first electrode sheet 21 are merely examples, and the present invention does not specifically limit the components and proportions of the materials in the first electrode sheet 21.

[0071] In order to verify the reduction in fracture phenomenon due to the first electrode sheet 21 of the present application being pre-rolled before cold rolling, and the influence of an electrode sheet using a thinner current collector and / or a higher compaction density on the energy density of the battery 100, several sets of comparative tests were conducted, the specific information of which is as follows:

[0072] A comparative example test and an example test were performed on multiple sets of first electrode sheets 21. In each set of comparative example tests, 10 samples of the first electrode sheets 21 were used, and in each set of example tests, 10 samples of the first electrode sheets 21 were used.

[0073] For multiple sets of comparative examples, the average value of the fracture frequency after each first electrode sheet 21 is stretched to the blank foil area and the electrode sheet is cold-rolled, and the average value of the energy density of the battery 100 including each first electrode sheet 21 are obtained.

[0074] Specific information regarding the comparative example tests and the example tests is as follows:

[0075] <Comparative Example 1> The first electrode sheet 21 is not rolled in advance, and the hollow foil region is stretched and developed after cold rolling of the first electrode sheet 21, and the weight density of the first active material layer 212 is 150 g / m 2 The compaction density of the first active material layer 212 is 3.85 g / m 3 is.

[0076] <Comparative Example 2> After the first electrode sheet 21 is preliminarily rolled, the first electrode sheet 21 is cold rolled. After the cold rolling, the hollow foil region is not stretched and developed, and the weight density of the first active material layer 212 is 150 g / m 2 The compaction density of the first active material layer 212 is 3.85 g / m 3The relationship between the thickness t1 of the first region 31 and the thickness t2 of the second region 32 is (t1-t2) / t1=10%, the minimum distance d1 between the first boundary line 34 and the first insulating layer 50 is 0.5 mm, and the ratio of the area S2 of the second region 32 (pre-rolling region) to the area S1 of the first tab 30 is 90%.

[0077] <Comparative Example 3> The only difference from Comparative Example 2 is that the relationship between the thickness t1 of the first region 31 and the thickness t2 of the second region 32 is (t1-t2) / t1=7%.

[0078] Example 1 After the first electrode sheet 21 is pre-rolled, the first electrode sheet 21 is cold-rolled. After the cold-rolling, the hollow foil region is not stretched, and the weight density of the first active material layer 212 is 150 g / m 2 The compaction density of the first active material layer 212 is 3.85 g / m 3 The relationship between the thickness t1 of the first region 31 and the thickness t2 of the second region 32 is (t1-t2) / t1=5%, the minimum distance D1 between the first boundary line 34 and the first insulating layer 50 is 0.5 mm, and the ratio of the area S2 of the second region 32 (pre-rolling region) to the area S1 of the first tab 30 is 90%.

[0079] The thickness test method for the first region 31 and the second region 32 involves selecting any three positions in the first region 31, measuring the thickness at each position with a vernier caliper, and then taking the arithmetic mean value, i.e., the thickness of the first region 31. The thickness test for the second region 32 is performed in a similar manner.

[0080] <Example 2> The only difference from Example 1 is that the relationship between the thickness t1 of the first region 31 and the thickness t2 of the second region 32 is (t1-t2) / t1=3.5%.

[0081] Example 3 The only difference from Example 1 is that the relationship between the thickness t1 of the first region 31 and the thickness t2 of the second region 32 is (t1-t2) / t1=3.0%.

[0082] Example 4 The only difference from Example 1 is that the relationship between the thickness t1 of the first region 31 and the thickness t2 of the second region 32 is (t1-t2) / t1=2.5%.

[0083] <Example 5> The only difference from Example 1 is that the relationship between the thickness t1 of the first region 31 and the thickness t2 of the second region 32 is (t1-t2) / t1=1.5%.

[0084] Example 6 The only difference from Example 1 is that the relationship between the thickness t1 of the first region 31 and the thickness t2 of the second region 32 is (t1-t2) / t1=0.5%.

[0085] Example 7 The difference from Example 6 is that the compaction density of the first active material layer 212 is 3.90 g / m 3 It is simply that.

[0086] Example 8 The difference from Example 6 is that the compaction density of the first active material layer 212 is 4.00 g / m 3 It is simply that.

[0087] Example 9 The difference from Example 6 is that the compaction density of the first active material layer 212 is 4.10 g / m 3 It is simply that.

[0088] Example 10 The difference from Example 6 is that the compaction density of the first active material layer 212 is 4.20 g / m 3 It is simply that.

[0089] Example 11 The only difference from Example 6 is that the minimum distance D1 between the first boundary line 34 and the first insulating layer 50 is 0.1 mm, and the ratio of the area S2 of the second region 32 (pre-rolling region) to the area S1 of the first tab 30 is 95%.

[0090] Example 12 The only differences from Example 6 are that the minimum distance D1 between the first boundary line 34 and the first insulating layer 50 is 0.3 mm, and the ratio of the area S2 of the second region 32 (pre-rolling region) to the area S1 of the first tab 30 is 93%.

[0091] Example 13 The only differences from Example 6 are that the minimum distance d1 between the first boundary line 34 and the first insulating layer 50 is 0.7 mm, and the ratio of the area S2 of the second region 32 (pre-rolling region) to the area S1 of the first tab 30 is 85%.

[0092] Example 14 The only differences from Example 6 are that the minimum distance d1 between the first boundary line 34 and the first insulating layer 50 is 1.0 mm, and the ratio of the area S2 of the second region 32 (pre-rolling region) to the area S1 of the first tab 30 is 80%.

[0093] Example 15 The only differences from Example 6 are that the minimum distance d1 between the first boundary line 34 and the first insulating layer 50 is 1.2 mm, and the ratio of the area S2 of the second region 32 (pre-rolling region) to the area S1 of the first tab 30 is 75%.

[0094] Example 16 The only difference from Example 6 is that the minimum distance d1 between the first boundary line 34 and the first insulating layer 50 is 1.5 mm, and the ratio of the area S2 of the second region 32 (pre-rolling region) to the area S1 of the first tab 30 is 60%.

[0095] Example 17 The only differences from Example 6 are that the minimum distance d1 between the first boundary line 34 and the first insulating layer 50 is 1.6 mm, and the ratio of the area S2 of the second region 32 (pre-rolling region) to the area S1 of the first tab 30 is 55%.

[0096] For the above-mentioned multiple sets of comparative examples and examples, the number of breaks per unit length for each first electrode sheet 21 is obtained, all first electrode sheets 21 are tracked, the energy density of the battery 100 including each first electrode sheet 21 is obtained, and the folding frequency of the first tab 30 in some examples is obtained. Statistics are collected and tabulated as follows:

[0097] [Table 1]

[0098] [Table 2]

[0099] [Table 3]

[0100] As is clear from Table 1, the first electrode sheet 21 of the present application is pre-rolled to the hollow foil area before cold rolling, compared to the first electrode sheet 21 that is not pre-rolled before cold rolling, which can improve the fracture phenomenon of the first electrode sheet 21.

[0101] As can be seen from Table 2, when the first electrode sheet 21 of the present embodiment is used, it can withstand a greater compaction strength, thereby increasing the compaction density of the first active material layer 212 and increasing the energy density of the battery 100.

[0102] As can be seen from Table 3, by employing the first electrode sheet 21 of the present example, the frequency of folding back the first tab 30 can be reduced, and the yield of the battery 100 can be increased.

[0103] As described above, in the battery 100 of the present application, tabs are installed in the first region 31 and the second region 32 along the width direction of the electrode sheet, the first region 31 is connected to the second region 32 and the tab, the second region 32 is rolled to pre-stretch it before cold rolling, and the thickness t1 of the first region 31 and the thickness t2 of the second region 32 satisfy 0.5%≦(t1−t2) / t1≦5%, which can reduce the phenomenon of the electrode sheet breaking after cold rolling. Furthermore, the energy density of the battery 100 can be increased by adopting a thinner current collector and / or a structure with a higher compaction density.

[0104] 15 , an embodiment of the present application further provides an electricity-consuming device 200 including the battery 100 described in any of the previous examples. The battery 100 can supply electrical energy to the electricity-consuming device 200.

[0105] In one embodiment, the electricity-using equipment 200 includes electronic devices such as drones, mobile phones, watches, tablets, and laptops.

[0106] In the above-mentioned electrical equipment 200, the first electrode sheet 21 of the battery 100 is pre-rolled and stretched in the hollow foil area before cold rolling, thereby improving the breakage problem of the first electrode sheet 21, and further adopting a thinner current collector and / or a higher compaction density structure to increase the energy density of the battery 100 and reduce the impact on the electrical equipment 200 caused by the low energy density of the battery 100.

[0107] Furthermore, those skilled in the art may make other modifications within the scope of the present invention, and of course, any modifications made based on the scope of the present invention should be included within the scope of the present invention. [Explanation of symbols]

[0108] 100 battery cells 10. Housing 11 Part 1 12 Part 2 13 Main body 14 Edge 141 Top Seal 142 Side seal 20 Electrode Assembly 21 First electrode sheet 211 Collection 1 Fluid 212 First active material layer 213 4th area 22 Second electrode sheet 221 Collection 2 Fluid 222 Second active material layer 23 Separator 30 First Tab 31 First area 32 Second area 33 Third area 34 First Boundary 40 Second Tab 50 First insulating layer 60 Second insulating layer 200 Electrical Equipment Z 1st direction X 2nd direction Y Third direction

Claims

1. A battery, an electrode sheet including a fluid collector and an active material layer provided on the fluid collector; a tab connected to the fluid collector and protruding from the electrode sheet along the width direction of the electrode sheet; the tab includes a first region and a second region along the width direction of the electrode sheet, the first region is located between the second region and the active material layer, the first region has a thickness t1, the second region has a thickness t2, and 0.5%≦(t1−t2) / t1≦5%.

2. 2. The battery according to claim 1, wherein 0.5%≦(t1−t2) / t1≦3.

3. 2. The battery according to claim 1, wherein 0.5%≦(t1−t2) / t1≦1.

5.

4. 2. The battery according to claim 1, wherein S1 is a projected area of the tab in the thickness direction of the tab, S2 is a projected area of the second region, and 60%≦S2 / S1≦95%.

5. 5. The battery according to claim 4, wherein 80%≦S2 / S1≦95%.

6. the tab further includes a third region located between the first region and the active material layer in the width direction of the electrode sheet and connecting the first region and the active material layer; 2. The battery according to claim 1, wherein the third region is provided with a first insulating layer located between the first region and the active material layer.

7. The battery of claim 6, further comprising a first boundary line at the boundary between the first region and the second region, wherein the minimum distance between the first boundary line and the first insulating layer is d1, and 0.1 mm≦d1≦1 mm.

8. The first insulating layer satisfies at least one of the following a, b, and c: a. The thickness of the first insulating layer is smaller than the thickness of the active material layer. b) In the width direction of the electrode sheet, the length of the tab is W1, the length of the first insulating layer is W2, W2 / W1≦0.5, and W2≧1 mm.

9. The battery of claim 6, wherein the first insulating layer comprises an inorganic material, and the inorganic material comprises at least one of aluminum oxide, magnesium oxide, and titanium oxide.

9. 2. The battery according to claim 1, wherein the number of the tabs is plural.

10. 2. The battery of claim 1, wherein the tab is a positive electrode tab.

11. An electrical equipment comprising the battery according to any one of claims 1 to 10.

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