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 usually includes coating and cold pressing processes. Among them, the electrode sheet is consolidated by cold pressing, which plays a very important role in improving the energy density and electrical performance of the battery. The active material layer area and the blank foil area forming the tab have different elongation degrees in the cold pressing process. Therefore, after the electrode sheet undergoes cold rolling, it is usually necessary to stretch the blank foil area in order to reduce the risk of deformation or warping of the tab. However, this stretching operation is likely to cause the electrode sheet to break, which affects the yield of cold pressing. In order to reduce the risk of breakage of the electrode sheet, the conventional technology generally uses a thicker current collector or reduces the compaction density of the electrode sheet. However, this measure is not only less effective in improving the breakage phenomenon, but also leads to 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 the electrode sheet breaking 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 includes a fluid collector and an active material layer disposed on the fluid collector, the tab is connected to the fluid collector, and the tab protrudes 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%.

[0005] In the above battery, the tabs are installed in the first and second regions along the width direction of the electrode sheet, the first region is located between the second region and the active material layer, the second region is rolled and pre-stretched before cold rolling, and the thickness t1 of the first region and the thickness t2 of the second region satisfy 0.5%≦(t1-t2) / t1≦5%, and the difference between the thickness of the first region and the thickness of the second region is not too large. If the difference is too large, stress is concentrated at the boundary, and the electrode sheet is likely to break. If the difference is too small, less than 0.5%, the second region does not reach the elongation effect, and the tab is likely to warp or bend. Therefore, the thickness t1 of the first region and the thickness t2 of the second region satisfy 0.5%≦(t1-t2) / t1≦5%, which reduces the phenomenon that the electrode sheet breaks after cold rolling, improves the yield rate of processing, and further allows the adoption of a thinner fluid collector and / or a higher compaction density structure, 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 manufacture, so that after cold rolling, the fluid collecting region covered with the active material layer has good extensibility, the second region has good extensibility after pre-rolling, and the first region has poor extensibility because it is adjacent to the active material layer and the first region cannot be rolled in the process. During the electrode sheet winding process, the first region is interposed between the active material layer and the second region, and the electrode sheet generates an arch in the second region, which causes warping and bending of the electrode sheet, so the area of ​​the first region is generally made as small as possible and the area of ​​the second region is made as large as possible. Thus, along the thickness direction of the tab, the area of ​​the projection of the tab is S1, and the area of ​​the projection of the second region is S2, and 60%≦S2 / S1≦95%, which is advantageous for reducing the warping and bending of the tab and improving the non-defective rate of winding, the flatness of the battery cell, and the energy density.

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

[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, and the first insulating layer serves as an insulating layer when the electrode sheet is wound or stacked to form an electrode assembly, and can reduce the risk of short circuit between the tab and other tabs / electrode sheets of the opposite polarity due to burrs puncturing the separator.

[0011] In some embodiments of the present application, the first region and the second region further include a first boundary line. The minimum distance between the first boundary line and the first insulating layer is d1, and 0.1 mm≦d1≦1 mm, 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 portion 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 multiple.

[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 previous 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 being broken after cold rolling, and further allowing a thinner current-collecting and / or higher compaction density structure to be adopted, thereby improving the energy density of the battery. [Brief description of the drawings]

[0017] [Figure 1]FIG. 1 is a schematic diagram of a three-dimensional structure of a battery according to an embodiment of the present application. [Diagram 2] FIG. 2 is a schematic diagram of a battery in an embodiment of the present application in a pre-packaged state. [Diagram 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. [Diagram 5] 5 is a cross-sectional view taken along line VV in FIG. 4. [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] 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] 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] 1 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. FIG. [Figure 14] 14 is a cross-sectional view taken along line XIV-XIV in FIG. 13. [Figure 15] BRIEF DESCRIPTION OF THE DRAWINGS Fig. 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 PREFERRED EMBODIMENTS

[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 clarified that when a component is deemed to be "connected" to another component, it may be directly connected to the other component or there may be intermediate media involved, and when a component is deemed to be "attached" to another component, it may be directly attached to the other component or there may be intermediate media involved.

[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 to which this application pertains. The terms used in this specification are for the purpose of describing particular embodiments only and are not intended to be limiting of the present application.

[0021] Currently, the production process of battery electrode sheets usually includes paint and cold pressing processes. Among them, the electrode sheet is consolidated by cold pressing, which plays a very important role in improving the energy density and electrical performance of the battery. The active material layer area and the blank foil area forming the tab have different elongation degrees in the cold pressing process. Therefore, after the electrode sheet undergoes cold rolling, it is usually necessary to stretch the blank foil area in order to reduce the risk of deformation or warping of the tab. However, this stretching operation is likely to cause the electrode sheet to break, which affects the yield of the cold press processing. In order to reduce the risk of breakage of the electrode sheet, the conventional technology generally uses a thicker current collector or reduces the compaction density of the electrode sheet. However, this measure is not only less effective in improving the breakage phenomenon, but also leads to 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 the tab protrudes 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%.

[0023] In the above-mentioned battery, the tab is provided in the first region and the second region along the width direction of the electrode sheet, and the first region is located between the second region and the active material layer. The second region is rolled to pre-stretch it, and 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 region and the second region must not be too large. If the difference between the two is too large, stress is concentrated at the boundary, making the electrode sheet prone to breakage. If the difference is too small, less than 0.5%, the second region does not achieve the stretching effect, and the tab is prone to warping and bending. Therefore, if 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 region and the second region cannot be made 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 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] As shown in Figures 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 portion 11 and a second portion 12 connected to each other, and the first portion 11 and the second portion 12 are connected opposite each other to form an internal space capable of accommodating 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 one another. 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 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 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 rolled up 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, or 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 integral 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 211 is exposed on the first electrode sheet 21 and the region where the first fluid collecting 211 is exposed on the first tab 30 are also called blank regions.

[0034] In order to increase the compaction density of the first active material layer 212 and increase the energy density of the battery 100, the first electrode sheet 21 needs to 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, so that the structural strength and stretching ability of the first current collector 211 are reduced. When stretching the blank foil area after cold rolling, the first current collector 211 is very likely to break, which affects the yield rate of processing. In the first electrode sheet 21 provided in the present application, at least a part of the blank foil area is rolled to pre-stretch it before cold rolling. Then, after cutting the first current collector 211 to form the first tab 30, the blank foil area that is pre-rolled and stretched constitutes at least a part 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 both sides 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 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%, where the second direction X is the thickness direction of the first electrode sheet 21.

[0039] In the battery 100 of the present invention, before the first electrode sheet 21 is cold-rolled, a part of the blank foil region is rolled and pre-expanded, so that the thickness t1 of the first region 31 that has not been pre-rolled and the thickness t2 of the second region 32 that has been pre-rolled and expanded satisfy 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 between the two is too large, stress is concentrated at the boundary, making the electrode sheet prone to breakage. If the difference between the two is too small, less than 0.5%, the second region 32 does not exert the stretching effect, and the first tab 30 is 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 blank foil region is stretched after cold rolling. In addition, the first electrode sheet 21 of the present application can adopt a thinner first current collector 211 and a higher compaction density first active material layer 212 when it is ensured 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%, and the fracture phenomenon of the first electrode sheet 21 can be further reduced, and a thinner fluid-collecting and / or 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, along the second direction X, the projection area of ​​the first tab 30 is S1, the projection area of ​​the second region 32 is S2, and 60%≦S2 / S1≦95%. Since the extensibility of the first region 31 is relatively poor and the extensibility of the second region 32 after the preliminary rolling is relatively good, if the area of ​​the second region 32 is too small, warping and bending easily occur during the winding process of the first electrode sheet 21. Therefore, along the thickness direction of the first tab 30, the projection area S1 of the first tab 30 and the projection area S2 of the second region 32 satisfy 60%≦S2 / S1≦95%. This is advantageous for reducing the 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 any of the following: 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 respectively located on both sides of the second boundary line 35.

[0047] The battery 100 further includes a first insulating layer 50 provided on the surface of the third region 33, and the first insulating layer 50 is 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 exerts an insulating protection effect, and can reduce the risk of short-circuiting between the first tab 30 and the second tab 40, thereby improving the safety performance of the battery 100. Compared with the battery 100 not provided with the first insulating layer 50, the burrs on the edge of the first tab 30 are likely to pierce the separator 23 and further electrically connect with the second tab 40, causing a short circuit in the battery. In one embodiment of the present application, by providing the first insulating layer 50, the burrs on the edge of the first tab 30 can be covered with the first insulating layer 50, and thus the risk of short-circuiting of the battery 100 can be reduced.

[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, and connects the first active material layer 212 and the third region 33.

[0050] The battery 100 further includes a second insulating layer 60 provided on the surface of the fourth region 213, and 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 plays an insulating role, 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 be electrically connected to the second electrode sheet 22, causing a short circuit in the battery 100. In one embodiment of the present application, the second insulating layer 60 is provided, so that the burrs on the edge of the first electrode sheet 21 are covered by the second insulating layer 60, and the risk of short-circuiting in the battery 100 can be further reduced.

[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 molded in a single process, which can simplify the manufacturing process of the battery 100, shorten the manufacturing cycle of the battery 100, and save 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 both the surfaces of the third region 33 and the fourth region 213.

[0053] In one embodiment, the battery further includes a first boundary line 34 at the boundary between the first region 31 and the second region 32 along the first direction Z, 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, and the first region 31 can be a transition region between the second region 32 and the first tab 30, which has been rolled and unfolded in advance, thereby enhancing the structural strength of the connection region between the first tab 30 and the first electrode sheet 21, reducing the risk of the first tab 30 bending or breaking along the connection point with the first tab 21, and improving 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 of the first tab 30 bending or breaking 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 of the battery 100 short - circuiting. 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 of the first tab 30 and the first insulating layer 50 along the first direction Z is beneficial to enhancing the current - conducting ability and heat - dissipation ability of the first tab 30, and improving the charge - discharge speed and heat - dissipation efficiency of the battery 100.

[0060] In one embodiment, the first insulating layer 50 contains inorganic substances. In one embodiment, the material of the inorganic substances 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 the 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 the 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 integral 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 one of copper, nickel, or nickel alloy.

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

[0067] In one embodiment, the second electrode sheet 22 is subjected to a pre-rolling operation on the uncoated blank foil area of ​​the second electrode sheet 22 before cold rolling, so as to reduce the phenomenon of breakage occurring in the second electrode sheet 22 after cold rolling. In one embodiment, the pre-rolling operation on the blank foil area of ​​the second electrode sheet 22 is similar to any of the embodiments of the pre-rolling operation on the blank foil area of ​​the first electrode sheet 21, and will not be described further 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 a suitable amount of solvent (e.g., deionized water, N-methylpyrrolidone) are mixed uniformly 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 area of ​​the first electrode sheet 21 obtained in step (3) is rolled and developed in advance, and then the coating area 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] It should be noted that the above-described manufacturing flow and process for first electrode sheet 21 are merely examples, and the present invention does not specifically limit the components and ratios of each material in first electrode sheet 21.

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

[0072] A comparison test and an example test were performed on a plurality of sets of first electrode sheets 21. In each set of comparison test, the number of samples of the first electrode sheets 21 was 10, and in each set of example test, the number of samples of the first electrode sheets 21 was 10.

[0073] For multiple sets of comparative examples, the average value of the breakage frequency after stretching of each first electrode sheet 21 to the blank foil region and cold rolling of the electrode sheet, 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 blank foil region is stretched and expanded after the cold rolling of the first electrode sheet 21, so that 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 It is.

[0076] <Comparative Example 2> After the first electrode sheet 21 is pre-rolled, the first electrode sheet 21 is cold-rolled. After the cold rolling, the blank foil region is not stretched or 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, no stretching is performed on the blank foil region. 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 is to select any three positions in the first region 31, measure the thickness at each position with a caliper, and then take the arithmetic average 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 just 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 just 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 just 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 just 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 difference from Example 6 is 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 difference from Example 6 is 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 difference from Example 6 is 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 difference from Example 6 is 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 difference from Example 6 is 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 of the examples is obtained. Statistics are collected and tabulated as follows:

[0097] [Table 1]

[0098] [Table 2]

[0099] [Table 3]

[0100] As is apparent from Table 1, the first electrode sheet 21 of the present application is pre-rolled against the hollow foil area before cold rolling, compared to the first electrode sheet 21 that is not pre-rolled before cold rolling, and the breakage phenomenon of the first electrode sheet 21 can be improved.

[0101] As can be seen from Table 2, when the first electrode sheet 21 of the embodiment of the present application is used, it can withstand a greater compression strength, and the compression density of the first active material layer 212 can be increased, thereby 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 embodiment of the present application, the frequency of folding back the first tab 30 can be reduced, and the yield rate of the battery 100 can be increased.

[0103] As described above, in the battery 100 of the present application, tabs are provided 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 and pre-stretched 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, and 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-using device 200 including the battery 100 according to any of the previous embodiments. The battery 100 can supply electrical energy to the electricity-using 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 structure with a higher compaction density 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] In addition, 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 disclosed in the present invention. [Explanation of symbols]

[0108] 100 Battery Cells 10. Housing 11 Part 1 12 Part 2 13 Main body 14 Border 141 Top Seal 142 Side seal 20 Electrode Assembly 21 First electrode sheet 211 First Collection Fluid 212 First active material layer 213 4th area 22 Second electrode sheet 221 Fluids, Volume 2 222 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 3rd 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 a width direction of the electrode sheet; a tab including a first region and a second region along a 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%.

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 in the thickness direction of the tab, a projected area of ​​the tab is S1, a projected area of ​​the second region is S2, and 60%≦S2 / S1≦95%.

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

6. In the width direction of the electrode sheet, the tab is located between the first region and the active material layer and further includes a third region 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, the minimum distance between the first boundary line and the first insulating layer being 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. The battery according to claim 6, wherein the first insulating layer includes an inorganic material, and the inorganic material includes at least one of aluminum oxide, magnesium oxide, and titanium oxide.

9. 2. The battery according to claim 1, wherein the number of said tabs is more than one.

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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