Electrode assembly and electrochemical device

Abstract

Embodiments of the present application relate to the technical field of batteries. Disclosed are an electrode assembly and an electrochemical device. The electrode assembly comprises a first electrode sheet, a second electrode sheet, a separator, and a first insulating member. The separator is arranged between the first electrode sheet and the second electrode sheet. The first electrode sheet comprises a first current collector and a first active material layer; the first current collector comprises a first main body part and a first empty foil part; the first active material layer is arranged on at least one surface of the first main body part; and the first main body part is spaced apart from the first empty foil part to form a first gap. The first insulating member is at least partially arranged at the first gap, and the first insulating member is connected to at least one of the first empty foil part, the first electrode sheet, and the second electrode sheet. The first insulating member is arranged at the first gap, so that the first empty foil part can be effectively insulated from the second electrode sheet, preventing an internal short circuit within the electrode assembly caused by electrical connection due to contact between the first empty foil part and the second electrode sheet, and improving the safety and reliability of the electrode assembly.

Description

Electrode assembly and electrochemical device

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese patent application No. 202410652415.0, filed on May 24, 2024, and entitled "Electrode assembly and electrochemical device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] Embodiments of the present application relate to the field of battery technology, in particular to an electrode assembly and an electrochemical device. BACKGROUND

[0004] At present, the common electrode assembly on the market is mainly composed of positive and negative electrode sheets and a separator arranged between the two. The positive and negative electrode sheets are the main places where chemical reactions occur in the battery, and the separator serves to isolate the positive and negative electrodes and prevent short circuit. At the same time, in order to facilitate the export of current and the assembly of the battery, a tab is usually provided on the electrode sheet, and the tab is connected to the external circuit through the tab.

[0005] However, in the existing electrode assembly design, the tab is usually directly connected to the electrode sheet and extends along the length direction of the electrode assembly, and is bent out of the battery after being welded to the adapter tab. Such a structure can cause the tab to occupy the head space of the battery, thereby reducing the energy density of the battery.

[0006] SUMMARY

[0007] The technical problem solved by embodiments of the present application is to provide an electrode assembly and an electrochemical device, which can reduce the occupation of the head space of the battery by the tab, and can prevent the tab from contacting the opposite tab to cause short circuit, thereby improving the safety and reliability of the electrode assembly.

[0008] One technical solution adopted by embodiments of the present application is to provide an electrode assembly, which includes a first electrode sheet, a second electrode sheet, a separator and a first insulating member. The separator is arranged between the first electrode sheet and the second electrode sheet. The first electrode sheet includes a first current collector and a first active material layer, the first current collector includes a first main body portion and a first hollow foil portion, the first active material layer is arranged on at least one surface of the first main body portion, and the first main body portion and the first hollow foil portion are arranged in a spaced manner to form a first gap. The first insulating member is arranged at least partially in the first gap, and the first insulating member is connected to at least one of the first hollow foil portion, the first electrode sheet and the second electrode sheet. By arranging the first insulating member at the first gap, the first hollow foil portion and the second electrode sheet can be effectively insulated, and contact between the two to form an electrical connection to cause internal short circuit of the electrode assembly can be prevented, thereby improving the safety and reliability of the electrode assembly.

[0009] In one or more possible embodiments, the first body part and the first empty foil part are spaced apart along a length direction of the electrode assembly to form a first gap, the first insulating member is connected to the first empty foil part, the length direction of the electrode assembly is perpendicular to a thickness direction of the electrode assembly; and in a projection along the thickness direction of the electrode assembly, a ratio S of an area of the first insulating member arranged on the first empty foil part to an area of the first empty foil part satisfies: 50%≤S≤100%. By arranging the first insulating member on at least half of the area of the first empty foil part, the insulating effect of the first insulating member on the first empty foil part can be effectively ensured.

[0010] In one or more possible embodiments, in a projection along the thickness direction of the electrode assembly, a ratio S of an area of the first insulating member arranged on the first empty foil part to an area of the first empty foil part satisfies: 80%≤S≤100%.

[0011] In one or more possible embodiments, the first empty foil part is provided with a first welding area, and in a projection along the thickness direction of the electrode assembly, the first insulating member covers the first welding area. The first insulating member covers the first welding area of the first empty foil part, which can on the one hand reinforce the connection of the adapter terminal and the first body part, and on the other hand can also wrap burrs at the welding position, preventing the burrs from damaging other adjacent first empty foil parts and / or diaphragms, and further ensuring the safety of the electrode assembly.

[0012] In one or more possible embodiments, the first tab is a cathode tab, the second tab is an anode tab, and in a projection along the thickness direction of the electrode assembly, the projection of the second tab covers part of the first gap.

[0013] In one or more possible embodiments, the first body part and the first empty foil part are spaced apart along a length direction of the electrode assembly to form a first gap, the first insulating member is connected to the first tab and / or the second tab.

[0014] In one or more possible embodiments, the first active material layer is provided with a first accommodation groove, the first accommodation groove is communicated with the first gap, and part of the first insulating member is arranged in the first accommodation groove; and / or, the second tab is provided with a second accommodation groove, the second accommodation groove is communicated with the first gap, and part of the first insulating member is arranged in the second accommodation groove. By arranging the first accommodation groove on the first tab and / or the second accommodation groove on the second tab, when the second insulating member is a molten insulating material such as a potting hot melt adhesive or an insulating glue, the first accommodation groove and / or the second accommodation groove can accommodate the first insulating member, so that the first insulating member can be better fixed and connected in the first tab and / or the second tab, preventing the first insulating member from being separated from the first tab and / or the second tab.

[0015] In one or more possible embodiments, the width of the first insulating member is greater than or equal to the width of the first hollow foil portion along the width direction of the electrode assembly, and the length direction of the electrode assembly, the width direction of the electrode assembly, and the thickness direction of the electrode assembly are perpendicular to each other. By setting the width of the first insulating member to be greater than or equal to the width of the first hollow foil portion, the first insulating member can effectively isolate the first hollow foil portion and the second tab even when the first hollow foil portion is in motion, preventing contact between the two and causing a short circuit.

[0016] In one or more possible embodiments, the length L of the first insulating member satisfies: 10 um≤L≤30 um along the length direction of the electrode assembly.

[0017] In one or more possible embodiments, the length L of the first insulating member satisfies: 16 um≤L≤20 um along the length direction of the electrode assembly.

[0018] In one or more possible embodiments, the first hollow foil portion and the first main body portion are spaced apart to form a first gap along the width direction of the electrode assembly, and the width direction of the electrode assembly and the thickness direction of the electrode assembly are perpendicular to each other.

[0019] In one or more possible embodiments, the first hollow foil portion and the first main body portion are spaced apart to form a first gap along the width direction of the electrode assembly.

[0020] In one or more possible embodiments, the second tab includes a second current collector and a second active material layer, the second current collector includes a second main body portion and a second hollow foil portion, the second active material layer is disposed on at least one surface of the second main body portion, the second main body portion and the second hollow foil portion are spaced apart to form a second gap; the electrode assembly further includes a second insulating member, at least a portion of the second insulating member is disposed in the second gap, the second insulating member is connected to the second hollow foil portion; and / or, the second insulating member is connected to the first tab and / or the second tab. The second insulating member further ensures that the second hollow foil portion is isolated from the first main body portion of the first tab, preventing contact between the second hollow foil portion and the first tab and causing a short circuit.

[0021] In one or more possible embodiments, the second main body portion and the second hollow foil portion are spaced apart to form a second gap along the length direction of the electrode assembly; or, the second main body portion and the second hollow foil portion are spaced apart to form a second gap along the width direction of the electrode assembly.

[0022] In one or more possible embodiments, the first current collector is provided with a first avoiding opening, and the second current collector is provided with a second avoiding opening; the second empty foil part is exposed to the first avoiding opening, and the first empty foil part is exposed to the second avoiding opening, as viewed along the thickness direction of the electrode assembly. By providing the second current collector with the second avoiding opening, the first empty foil part can be connected to the adapter terminal, and the second avoiding opening can avoid the first empty foil part from contacting the second pole piece to cause internal short circuit of the electrode assembly. By providing the first current collector with the first avoiding opening, the second empty foil part can be connected to the adapter terminal, and the first avoiding opening can avoid the second empty foil part from contacting the first pole piece to cause internal short circuit of the electrode assembly.

[0023] In one or more possible embodiments, the first insulating member includes any one of potting hot melt adhesive, insulating adhesive paper, and insulating adhesive.

[0024] In one or more possible embodiments, the first pole piece, the second pole piece, and the diaphragm are multiple, the first pole piece and the second pole piece are alternately stacked, and the diaphragm is arranged between the first pole piece and the second pole piece; the first main body part of the multiple first pole pieces and the second main body part of the multiple second pole pieces jointly constitute a total main body part of the electrode assembly, the multiple first empty foil parts constitute a first lug group of the electrode assembly, and the total main body part and the first lug group are arranged with a first space to form a first empty slot; a first side wall is arranged on a side of the total main body part facing the first empty slot, a second side wall is arranged on a side of the first lug group facing the first empty slot, and at least part of the first insulating member is connected between the first side wall and the second side wall.

[0025] In one or more possible embodiments, along the thickness direction of the electrode assembly, the total main body part is provided with opposite first top and bottom walls, and the first lug group is provided with opposite second top and bottom walls; the first insulating member is arranged on the first top wall, the first side wall, and the first bottom wall; and / or the first insulating member is arranged on the second top wall, the second side wall, and the second bottom wall.

[0026] In one or more possible embodiments, the multiple second empty foil parts constitute a second lug group of the electrode assembly, and the total main body part and the second lug group are arranged with a second space to form a second empty slot; a third side wall is arranged on a side of the second lug group facing the second empty slot, a fourth side wall is arranged on a side of the total main body part facing the second empty slot, and at least part of the second insulating member is connected between the third side wall and the fourth side wall.

[0027] Another technical solution adopted by the embodiments of the present application is to provide an electrochemical device including an electrode assembly.

[0028] The electrode assembly of the embodiment of the present application comprises a first pole piece, a second pole piece, a separator and a first insulating member. The separator is arranged between the first pole piece and the second pole piece; the first pole piece comprises a first current collector and a first active material layer, the first current collector comprises a first main body part and a first hollow foil part, the first active material layer is arranged on at least one surface of the first main body part, and the first main body part and the first hollow foil part are arranged in a spaced manner to form a first gap; the first insulating member is arranged at least partially in the first gap, and the first insulating member is connected with the first hollow foil part; and / or the first insulating member is connected with the first pole piece and / or the second pole piece. By arranging the first insulating member at the first gap, the first hollow foil part and the second pole piece can be effectively insulated, and contact between the first hollow foil part and the second pole piece to form an electrical connection to cause internal short circuit of the electrode assembly can be prevented, thereby improving the safety and reliability of the electrode assembly. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application, the drawings needed in the specific embodiment description will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual proportions.

[0030] FIG. 1 is a schematic view of an electrode assembly according to an embodiment of the present application.

[0031] FIG. 2 is an exploded view of the electrode assembly according to an embodiment of the present application.

[0032] FIG. 3 is an exploded view of the first pole piece in part A of FIG. 2.

[0033] FIG. 4 is a schematic view of the electrode assembly according to an embodiment of the present application from another perspective.

[0034] FIG. 5 is an enlarged view of part B of FIG. 4.

[0035] FIG. 6 is an enlarged view of part B of FIG. 4, in which the first insulating member is arranged on the first hollow foil part.

[0036] FIG. 7 is an enlarged view of part B of FIG. 4, in which the first insulating member is arranged on the first pole piece and / or the second pole piece.

[0037] FIG. 8 is an enlarged view of part A of FIG. 2, in which the first pole piece and / or the second pole piece is provided with a receiving groove.

[0038] FIG. 9 is an exploded view of the second pole piece in part C of FIG. 2.

[0039] FIG. 10 is an enlarged view of part D of FIG. 1, in which the first insulating member is omitted.

[0040] FIG. 11 is an enlarged view of part D of FIG. 1, in which the first insulating member is omitted and the view is taken along the width direction of the electrode assembly.

[0041] FIG. 12 is an enlarged view of part E of FIG. 1, in which the view is adjusted.

[0042] Fig. 13 is an enlarged view of the portion E in Fig. 1, as viewed in the width direction of the electrode assembly.

[0043] Fig. 14 is a schematic view of another embodiment of the electrode assembly of the present application.

[0044] Fig. 15 is a schematic view of still another embodiment of the electrode assembly of the present application. DETAILED DESCRIPTION

[0045] For the purpose of facilitating the understanding of the present application, the present application will be described in more detail below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or one or more intervening elements can be present therebetween. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or one or more intervening elements can be present therebetween. The terms "upper", "lower", "inner", "outer", "vertical", "horizontal", and the like as used in the present specification to indicate the orientation or positional relationship based on the orientation or position shown in the drawings, are merely used for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present application. In addition, the terms "first", "second", and the like are used only for the purpose of description and should not be construed as indicating or implying relative importance.

[0046] Unless otherwise defined, all technical and scientific terms used in the present specification are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are merely intended for the purpose of describing the specific embodiments and are not intended to limit the present application. The term "and / or" as used in the present specification includes any and all combinations of one or more of the associated listed items.

[0047] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0048] Referring to Fig. 1, an embodiment of an electrode assembly 100 is provided, which has a length direction X, a width direction Y and a thickness direction Z perpendicular to each other. Referring to Fig. 2 in conjunction, the electrode assembly 100 includes a first electrode tab 10, a second electrode tab 20, a separator 30 and a first insulating member 41. The first electrode tab 10 and the second electrode tab 20 are arranged in a stacked manner in the thickness direction Z of the electrode assembly 100, and the separator 30 is arranged between the first electrode tab 10 and the second electrode tab 20 to prevent the first electrode tab 10 and the second electrode tab 20 from directly contacting and short-circuiting. The first electrode tab 10 and the second electrode tab 20 have opposite polarities, one of which is a cathode electrode tab and the other of which is an anode electrode tab.

[0049] Referring to FIG. 3, the first tab 10 includes a first current collector 11 and a first active material layer 12, the first current collector 11 includes a first body portion 111 and a first hollow foil portion 112 connected to each other, and the first active material layer 12 is disposed on at least one surface of the first body portion 111, while a surface of the first hollow foil portion 112 is not provided with the first active material layer 12. The first body portion 111 and the first hollow foil portion 112 are disposed at intervals in a length direction X or a width direction Y of the electrode assembly 100 to form a first notch 113. At least a part of the first insulating member 41 is disposed in the first notch 113, and the first insulating member 41 is connected to at least one of the first hollow foil portion 112, the first tab 10, and the second tab 20. By disposing the first insulating member 41 at the first notch 113, the first hollow foil portion 112 and the second tab 20 can be effectively insulated from each other, and contact between the first hollow foil portion 112 and the second tab 20 to form an electrical connection can be prevented, thereby improving the safety and reliability of the electrode assembly 100.

[0050] The first current collector 11 in the first tab 10 can be obtained by a die-cutting process. As an example, the first current collector 11 before processing is a regular rectangular current collector sheet, and the first body portion 111 and the first hollow foil portion 112 are obtained by cutting a part of the current collector sheet, and the area corresponding to the cut part forms the first notch 113. When the first active material layer 12 is coated only on the surface of the first body portion 111, the first hollow foil portion 112 constitutes a conductive tab of the first tab 10. The first current collector 11 obtained by the above process can avoid the conductive tab of the first tab 10 protruding from the first body portion 111, thereby reducing the space occupied in the battery and improving the energy density of the battery.

[0051] The first insulating member 41 includes, but is not limited to, any one of a potting hot melt adhesive, an insulating adhesive tape, and an insulating adhesive, and any other material having an insulating effect. The first insulating member 41 is disposed at the first notch 113, i.e., the first insulating member 41 is located between the first hollow foil portion 112 and the first body portion 111 and the second tab 20, and can achieve insulation between the first hollow foil portion 112 and the second tab 20.

[0052] The first insulating member 41 is connected to the first empty foil part 112, and the ratio S of the area S1 of the first insulating member 41 projected along the thickness direction Z of the electrode assembly 100 on the first empty foil part 112 to the area S2 of the first empty foil part 112 itself satisfies 50%≤S≤100%. By arranging the first insulating member 41 on at least half of the area of the first empty foil part 112, the insulation effect of the first insulating member 41 on the first empty foil part 112 can be effectively guaranteed. In addition, the first insulating member 41 needs to be arranged on the area of the first empty foil part 112 close to the first notch 113. In other embodiments, the ratio S of the area S1 of the first insulating member 41 projected along the thickness direction Z of the electrode assembly 100 on the first empty foil part 112 to the area S2 of the first empty foil part 112 itself satisfies 80%≤S≤100%.

[0053] Please refer to FIG. 5, since the first empty foil area is the conductive tab of the first tab 10, the first empty foil part 112 is provided with a first welding area 1121 configured to weld a terminal extension outside the battery to form a positive or negative electrode of the battery. The first insulating member 41 covers the first welding area 1121 projected along the thickness direction Z of the electrode assembly 100. By further expanding the area of the first insulating member 41 covering the first main body part 111 to cover the area where the terminal and the first empty foil part 112 are welded, on the basis of insulating the first empty foil part 112 from the second tab 20 at the first notch 113, the first insulating member 41 can not only reinforce the connection between the terminal and the first main body part 111, but also wrap the burrs at the welding position, preventing the burrs from damaging other adjacent first empty foil parts 112 and / or the separator 30, further ensuring the safety of the electrode assembly 100.

[0054] Referring to FIG. 5, in some embodiments, the first tab 10 is a cathode tab, the second tab 20 is an anode tab, and the projection of the second tab 20 covers part of the first notch 113 in the thickness direction Z of the electrode assembly 100, that is, the second tab 20 protrudes beyond the first tab 10 in the length direction X or the width direction Y of the electrode assembly 100 so that part of the second tab 20 enters the first notch 113. In order to prevent the electrode assembly 100 from lithium precipitation due to insufficient space for lithium ion insertion during charging and discharging, the size of the anode tab is usually set to be larger than that of the cathode tab, so that the anode tab has enough space for lithium ion insertion. That is, at the first notch 113, part of the second tab 20 protrudes beyond the first tab 10, causing the first empty foil part 112 on the first tab 10 to be closer to the second tab 20, which further increases the risk of short circuit contact between the first empty foil part 112 and the second tab 20. Therefore, the first insulating member 41 is arranged at the first notch 113 to insulate the first empty foil part 112 and the second tab 20, which can effectively solve the above risk.

[0055] Referring to FIG. 7, in order to insulate the first empty foil part 112 and the second tab 20, in addition to the above-mentioned embodiment in which the first insulating member 41 is connected to the first empty foil part 112, the first insulating member 41 can also be arranged on the other side of the first notch 113, that is, the first insulating member 41 is connected to the first tab 10 and / or the second tab 20. Since the first tab 10 and the second tab 20 are arranged in layers, even if the first insulating member 41 is arranged on the first tab 10, the first empty foil part 112 and the second tab 20 can be effectively insulated. Of course, when the first insulating member 41 is an insulating adhesive tape, the first insulating member 41 is preferably connected to the second tab 20, so as to ensure that the first empty foil part 112 and the second tab 20 are insulated by the first insulating member 41.

[0056] In some embodiments, referring to FIG. 8, the first active material layer 12 is provided with a first receiving groove 121, the first receiving groove 121 is communicated with the first notch 113, and part of the first insulating member 41 is arranged in the first receiving groove 121. And / or, the second tab 20 is provided with a second receiving groove 221, the second receiving groove 221 is communicated with the first notch 113, and part of the first insulating member 41 is arranged in the second receiving groove 221. By arranging the first receiving groove 121 on the first tab 10 and / or the second receiving groove 221 on the second tab 20, when the second insulating member 42 is a molten insulating material such as a potting hot melt adhesive or an insulating glue, the first receiving groove 121 and / or the second receiving groove 221 can accommodate the first insulating member 41, so that the first insulating member 41 can be better fixedly connected to the first tab 10 and / or the second tab 20, preventing the first insulating member 41 from being separated from the first tab 10 and / or the second tab 20.

[0057] In some embodiments, referring to FIG. 8, when the first insulating member 41 is disposed on the first foil-free portion 112 and the first insulating member 41 is a molten insulating material such as potting hot melt adhesive, insulating glue, etc., a first anti-falling portion 1122 is provided on the first foil-free portion 112 near the first notch 113, and the first insulating member 41 is connected to the first anti-falling portion 1122. The roughness of the surface of the first anti-falling portion 1122 is greater than that of the rest of the first foil-free portion 112, so that the molten first insulating member 41 can be better connected to the first foil-free portion 112, thereby increasing the firmness of the connection between the solidified first insulating member 41 and the first foil-free portion 112.

[0058] In some embodiments, referring to FIG. 8, when the first insulating member 41 is disposed on the first pole piece 10 and / or the second pole piece 20 and the first insulating member 41 is a molten insulating material such as potting hot melt adhesive, insulating glue, etc., a second anti-falling portion 1111 is provided on the surface of the first main body portion 111 of the first pole piece 10 exposed to the first receiving groove 121, and the first insulating member 41 is connected to the second anti-falling portion 1111. The roughness of the surface of the second anti-falling portion 1111 is greater than that of the rest of the first main body portion 111, so that the molten first insulating member 41 can be better connected to the first main body portion 111, thereby increasing the firmness of the connection between the solidified first insulating member 41 and the first main body portion 111. Similarly, a third anti-falling portion 2111 is provided on the surface of the current collector of the second pole piece 20 exposed to the second receiving groove 221, and the first insulating member 41 is connected to the third anti-falling portion 2111.

[0059] In some embodiments, referring to FIGS. 6 and 7, in the embodiment in which the first insulating member 41 is disposed on the first foil-free portion 112 or the embodiment in which the first insulating member 41 is disposed on the first pole piece 10 and / or the second pole piece 20, the width K1 of the first insulating member 41 is greater than or equal to the width K2 of the first foil-free portion 112 along the width direction Y of the electrode assembly 100. Since the first main body portion 111 and the first foil-free portion 112 are spaced apart in the length direction X of the electrode assembly 100 and the first notch 113 is located at the edge of the first current collector 11, the end of the first foil-free portion 112 can move in the length direction X of the electrode assembly 100 relative to the first main body portion 111. By setting the width of the first insulating member 41 to be greater than or equal to the width of the first foil-free portion 112, even if the first foil-free portion 112 moves, the first insulating member 41 can effectively insulate the first foil-free portion 112 and the second pole piece 20, preventing contact between them and causing a short circuit.

[0060] In some embodiments, referring to FIGS. 6 and 7, the length L of the first insulating member 41 satisfies 10um≤L≤30um along the length direction X of the electrode assembly 100. In order to ensure the insulation effect of the first insulating member 41, the first insulating member 41 needs to have a certain length, otherwise the first insulating member 41 that is too thin is easy to break and lose the insulation effect. In other embodiments, the length L of the first insulating member 41 satisfies 16um≤L≤20um. The first insulating member 41 in this size can not only ensure the insulation effect, but also reduce the weight of the battery assembly.

[0061] It can be understood that, in addition to being connected to the first empty foil portion 112, or the first insulating member 41 is connected to the first tab 10 and / or the second tab 20, the first insulating member 41 can also be connected to the first empty foil portion 112 and the first tab 10 and / or the second tab 20 at the same time, that is, the first insulating member 41 fills the first gap 113. Such a structure can not only effectively isolate the first empty foil portion 112 from contacting the second tab 20, but also help to increase the strength of the first empty foil portion 112 and reduce the offset movement of the first empty foil portion 112 relative to the first main body portion 111.

[0062] In some embodiments, referring to FIG. 9, the second tab 20 includes a second current collector 21 and a second active material layer 22, the second current collector 21 includes a second main body portion 211 and a second empty foil portion 212 connected together, and the second active material layer 22 is arranged on at least one surface of the second main body portion 211, and the second empty foil portion 212 is not provided with the second active material layer 22. The second main body portion 211 and the second empty foil portion 212 are arranged in a spaced manner in the length direction X or the width direction Y of the electrode assembly 100 to form a second gap 213. Since the size of the second tab 20 is greater than or equal to the size of the first tab 10, the distance between the second main body portion 211 and the second empty foil portion 212 after lamination is less than or equal to the distance between the first main body portion 111 and the second empty foil portion 212. That is, at the second gap 213, the probability of short circuit caused by the contact between the second empty foil portion 212 and the first main body portion 111 of the first tab 10 is small, and the insulating structure can not be arranged at the second gap 213.

[0063] In some embodiments, referring to FIG. 2 and FIG. 4, the first current collector 11 is provided with a first avoiding opening 114, and the second current collector 21 is provided with a second avoiding opening 214. When the first electrode tab 10 and the second electrode tab 20 are stacked, the second empty foil part 212 is exposed to the first avoiding opening 114, and the first empty foil part 112 is exposed to the second avoiding opening 214, as viewed along the thickness direction Z of the electrode assembly 100. By providing the second avoiding opening 214 on the second current collector 21, the first empty foil part 112 can be connected to the adapter terminal, and the second avoiding opening 214 can avoid the first empty foil part 112, so as to prevent the first empty foil part 112 from contacting the second electrode tab 20 and causing internal short circuit of the electrode assembly 100. By providing the first avoiding opening 114 on the first current collector 11, the second empty foil part 212 can be connected to the adapter terminal, and the first avoiding opening 114 can avoid the second empty foil part 212, so as to prevent the second empty foil part 212 from contacting the first electrode tab 10 and causing internal short circuit of the electrode assembly 100.

[0064] In some embodiments, referring to FIG. 2, in order to further ensure that the second empty foil part 212 is isolated from the first main body part 111 of the first electrode tab 10, the electrode assembly 100 further comprises a second insulating member 42, at least a part of the second insulating member 42 is arranged at the second gap 213, the second insulating member 42 is connected to the second empty foil part 212, and / or the second insulating member 42 is connected to the first electrode tab 10 and / or the second electrode tab 20.

[0065] The second insulating member 42 includes, but is not limited to, any one of potting hot melt adhesive, insulating adhesive tape and insulating adhesive, and any other material having an insulating effect. The second insulating member 42 is arranged at the second gap 213, i.e. the second insulating member 42 is located between the second empty foil part 212 and the second main body part 211 and the first electrode tab 10, so as to achieve insulation between the second empty foil part 212 and the first electrode tab 10.

[0066] In some embodiments, referring to FIG. 1 and FIG. 2, the number of the first electrode tabs 10, the second electrode tabs 20 and the separators 30 in the electrode assembly 100 is multiple, the multiple first electrode tabs 10 and the multiple second electrode tabs 20 are arranged in turn and alternately stacked, and the separators 30 are arranged between adjacent first electrode tabs 10 and second electrode tabs 20. The first main body part 111 of the multiple first electrode tabs 10 and the second main body part 211 of the multiple second electrode tabs 20 are stacked to form a total main body part 50 of the electrode assembly 100, the multiple first empty foil parts 112 are stacked to form a first tab group 60 of the electrode assembly 100, and the total main body part 50 and the first tab group 60 are spaced apart to form a first empty slot 70, that is, the multiple first notches 113 form the first empty slot 70. Referring to FIG. 10, the side of the total main body part 50 facing the first empty slot 70 is provided with a first side wall 51, the side of the first tab group 60 facing the first empty slot 70 is provided with a second side wall 61, and at least part of the first insulating member 41 is connected between the first side wall 51 and the second side wall 61, thereby isolating the first tab group 60 and the total main body part 50.

[0067] As an example, referring to FIG. 10 and FIG. 11, along the thickness direction Z of the electrode assembly 100, the total main body part 50 is provided with opposite first top and bottom walls 52 and 53, and the first tab group 60 is provided with opposite second top and bottom walls 62 and 63. The first insulating member 41 is arranged on the first top wall 52, the first side wall 51 and the first bottom wall 53; and / or, the first insulating member 41 is arranged on the second top wall 62, the second side wall 61 and the second bottom wall 63.

[0068] Specifically, when the first insulating member 41 is a molten insulating material such as a potting hot melt adhesive and an insulating glue, and is connected to the total main body part 50, the first insulating member 41 is solidified and arranged on the first top wall 52, the first side wall 51 and the first bottom wall 53 of the total main body part 50, and part of the first insulating member 41 is embedded between the first electrode tabs 10 and the second electrode tabs 20. When the first insulating member 41 is a molten insulating material such as a potting hot melt adhesive and an insulating glue, and is connected to the first tab group 60, the first insulating member 41 is solidified and arranged on the second top wall 62, the second side wall 61 and the second bottom wall 63 of the first tab group 60, and part of the first insulating member 41 is embedded inside the first tab group 60.

[0069] Specifically, referring to FIG. 11, when the first insulating member 41 is a layered insulating material such as an insulating adhesive paper, and is connected to the total main body part 50, the first insulating member 41 is pasted on the first top wall 52, the first side wall 51 and the first bottom wall 53 of the total main body part 50, and the first insulating member 41 is generally in a U-shaped structure. When the first insulating member 41 is a layered insulating material such as an insulating adhesive paper, and is connected to the first tab group 60, the first insulating member 41 is pasted on the second top wall 62, the second side wall 61 and the second bottom wall 63 of the first tab group 60, and the first insulating member 41 is generally in a U-shaped structure.

[0070] In some embodiments, referring to FIG. 12, the plurality of second foil empty portions 212 are stacked to form the second tab group 80 of the electrode assembly 100. The second empty space 90 is formed between the total body portion 50 and the second tab group 80, i.e., the plurality of second notches 213 collectively form the second empty space 90. The side of the second tab group 80 facing the second empty space 90 has a third side wall 81, and the side of the total body portion 50 facing the second empty space 90 has a fourth side wall 54. At least part of the second insulating member 42 is connected between the third side wall 81 and the fourth side wall 54, thereby insulating the second tab group 80 and the total body portion 50.

[0071] As an example, referring to FIGS. 12 and 13, the second tab group 80 has opposite third top and bottom walls 82 and 83 in the thickness direction Z of the electrode assembly 100. The second insulating member 42 is disposed on the third top wall 82, the third side wall 81, and the third bottom wall 83; and / or the second insulating member 42 is disposed on the first top wall 52, the fourth side wall 54, and the first bottom wall 53. The specific connection manner and structure of the second insulating member 42 can refer to the connection manner and structure of the first insulating member 41 described above, and will not be described here again.

[0072] In any of the above embodiments, the first body portion 111 and the first foil empty portion 112 are spaced apart in the length direction X of the electrode assembly 100 to form the first notch 113, and the second body portion 211 and the second foil empty portion 212 are spaced apart in the length direction X of the electrode assembly 100 to form the second notch 213. Referring to FIGS. 14 and 15, the present application also provides some embodiments of the electrode assembly 100, in which the first body portion 111 and the first foil empty portion 112 are spaced apart in the width direction Y of the electrode assembly 100 to form the first notch 113, and the second body portion 211 and the second foil empty portion 212 are spaced apart in the width direction Y of the electrode assembly 100 to form the second notch 213. The specific connection structure and manner of the first insulating member 41 with the first foil empty portion 112 and the first and / or second tab 10 can refer to the above embodiment in which the first body portion 111 and the first foil empty portion 112 are spaced apart in the length direction X, and the specific connection structure and manner of the second insulating member 42 with the second foil empty portion 212 and the first and / or second tab 10 can refer to the above embodiment in which the second body portion 211 and the second foil empty portion 212 are spaced apart in the length direction X, and will not be described here again.

[0073] In the embodiment in which the first hollow foil portion 112 is arranged apart from the first main body portion 111 along the width direction Y of the electrode assembly 100 to form the first gap 113, as an example, as shown in FIG. 14, the first hollow foil portion 112 can be located at the edge of the first tab 10, i.e., along the width direction Y of the electrode assembly 100, only one side of the first hollow foil portion 112 is arranged apart from the first main body portion 111 to form the first gap 113. As another example, as shown in FIG. 15, the first hollow foil portion 112 is not located at the edge of the first tab 10, but is offset close to the middle region of the first tab 10, i.e., along the width direction Y of the electrode assembly 100, both sides of the first hollow foil portion 112 are arranged apart from the first main body portion 111 to form the first gap 113. By adjusting the position of the first hollow foil portion 112 relative to the first main body portion 111, thereby changing the position of the first hollow foil portion 112 along the width direction Y of the electrode assembly 100, the position of the adapter terminal connected to the first hollow foil portion 112 extending out of the electrochemical device can be adjusted, so that the position of the adapter terminal is more flexible and is not limited by the position of the external connection. In addition, the position of the second hollow foil portion 212 on the second tab 20 relative to the second main body portion 211 can also refer to the position of the first hollow foil portion 112 relative to the first main body portion 111 in the first tab 10, which will not be described here.

[0074] The present application also provides an electrochemical device embodiment, which comprises a shell and an electrode assembly 100 arranged in the interior of the shell. The shell can be made of a hard material such as steel, or can be made of a soft material such as an aluminum plastic film. For the specific structure and function of the electrode assembly 100, please refer to any of the above embodiments, which will not be described here.

[0075] The electrode assembly 100 of the embodiment of the present application comprises a first tab 10, a second tab 20, a separator 30, and a first insulating member 41. The separator 30 is arranged between the first tab 10 and the second tab 20; the first tab 10 comprises a first current collector 11 and a first active material layer 12, the first current collector 11 comprises a first main body portion 111 and a first hollow foil portion 112, the first active material layer 12 is arranged on at least one surface of the first main body portion 111, the first main body portion 111 and the first hollow foil portion 112 are arranged apart to form a first gap 113; the first insulating member 41 is at least partially arranged in the first gap 113, the first insulating member 41 is connected with the first hollow foil portion 112; and / or, the first insulating member 41 is connected with the first tab 10 and / or the second tab 20. By arranging the first insulating member 41 at the first gap 113, the first hollow foil portion 112 and the second tab 20 can be effectively insulated to prevent contact between them to form an electrical connection and cause internal short circuit of the electrode assembly 100, thereby improving the safety and reliability of the electrode assembly 100.

[0076] The above merely describes the embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, which is made by using the content of the present application specification and drawings, is also included in the patent protection scope of the present application.

Claims

1. An electrode assembly, characterized by, Comprising: a first tab, a second tab, and a separator, the separator being disposed between the first tab and the second tab; the first tab comprising a first current collector and a first active material layer, the first current collector comprising a first main portion and a first hollow portion, the first active material layer being disposed on at least one surface of the first main portion, the first main portion being spaced apart from the first hollow portion to form a first gap; a first insulating member being at least partially disposed in the first gap, the first insulating member being connected to at least one of the first hollow portion, the first tab, and the second tab.

2. The electrode assembly according to claim 1, wherein: the first main portion and the first hollow portion are spaced apart along a length direction of the electrode assembly to form the first gap, the first insulating member is connected to the first hollow portion, and the length direction of the electrode assembly is perpendicular to a thickness direction of the electrode assembly; a ratio S of an area of the first insulating member disposed on the first hollow portion to an area of the first hollow portion projected along the thickness direction of the electrode assembly satisfies 50%≤S≤100%.

3. The electrode assembly of claim 2, wherein, 80％≤S≤100％。 4. The electrode assembly according to claim 2, wherein: the first hollow portion is provided with a first welding area, and the first insulating member covers the first welding area projected along the thickness direction of the electrode assembly.

5. The electrode assembly according to any one of claims 1 to 4, wherein: the first tab is a cathode tab, the second tab is an anode tab, and a projection of the second tab covers part of the first gap projected along the thickness direction of the electrode assembly.

6. The electrode assembly according to claim 1, wherein: the first main portion and the first hollow portion are spaced apart along a length direction of the electrode assembly to form the first gap, and the first insulating member is connected to the first tab and / or the second tab.

7. The electrode assembly according to claim 6, wherein: the first active material layer is provided with a first accommodation groove, the first accommodation groove is in communication with the first gap, and a part of the first insulating member is disposed in the first accommodation groove; and / or the second tab is provided with a second accommodation groove, the second accommodation groove is in communication with the first gap, and a part of the first insulating member is disposed in the second accommodation groove.

8. The electrode assembly according to claim 2 or 6, wherein: a width of the first insulating member is greater than or equal to a width of the first hollow portion along a width direction of the electrode assembly, and the length direction of the electrode assembly, the width direction of the electrode assembly, and the thickness direction of the electrode assembly are perpendicular to each other.

9. The electrode assembly according to claim 8, wherein: a length L of the first insulating member satisfies 10um≤L≤30um along the length direction of the electrode assembly.

10. The electrode assembly according to claim 9, wherein: the length L of the first insulating member satisfies 16um≤L≤20um along the length direction of the electrode assembly.

11. The electrode assembly of claim 1, wherein the first empty tab portion is spaced apart from the first main body portion to form the first gap along a width direction of the electrode assembly.

12. The electrode assembly of claim 11, wherein the first empty tab portion is spaced apart from the first main body portion on both sides of the first empty tab portion to form the first gap along the width direction of the electrode assembly.

13. The electrode assembly of any one of claims 1, wherein the second tab includes a second current collector and a second active material layer, the second current collector includes a second main body portion and a second empty tab portion, the second active material layer is disposed on at least one surface of the second main body portion, and the second main body portion is spaced apart from the second empty tab portion to form a second gap.

14. The electrode assembly of claim 13, wherein the second main body portion is spaced apart from the second empty tab portion along a length direction of the electrode assembly to form the second gap, or the second main body portion is spaced apart from the second empty tab portion along a width direction of the electrode assembly to form the second gap.

15. The electrode assembly of claim 13, wherein the first current collector is provided with a first avoiding opening, and the second current collector is provided with a second avoiding opening.

16. The electrode assembly of claim 13, wherein the first insulating member includes any one of a potting hot melt adhesive, an insulating adhesive tape, and an insulating adhesive, and / or the second insulating member includes any one of a potting hot melt adhesive, an insulating adhesive tape, and an insulating adhesive.

17. The electrode assembly of claim 13, wherein the first tabs, the second tabs, and the separators are each a plurality of, the first tabs and the second tabs are alternately stacked, and the separators are disposed between the first tabs and the second tabs.

18. The electrode assembly of claim 17, wherein the first main body portions of the first tabs and the second main body portions of the second tabs collectively form a total main body portion of the electrode assembly, the first empty tab portions collectively form a first tab group of the electrode assembly, and the total main body portion is spaced apart from the first tab group to form a first empty slot.

19. The electrode assembly of claim 18, wherein the total main body portion is provided with a first side wall on a side facing the first empty slot, the first tab group is provided with a second side wall on a side facing the first empty slot, and at least a portion of the first insulating member is connected between the first side wall and the second side wall. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The total body part is provided with opposite first top and bottom walls along the thickness direction of the electrode assembly, and the first tab group is provided with opposite second top and bottom walls; The first insulating member is arranged on the first top wall, the first side wall and the first bottom wall at the same time; And / or, the first insulating member is arranged on the second top wall, the second side wall and the second bottom wall at the same time.

19. The electrode assembly according to claim 17, wherein A plurality of the second hollow foil parts constitute a second tab group of the electrode assembly, and the total body part and the second tab group are arranged with a second hollow gap therebetween; The second tab group is provided with a third side wall on the side facing the second hollow gap, the total body part is provided with a fourth side wall on the side facing the second hollow gap, and at least part of the second insulating member is connected between the third side wall and the fourth side wall.

20. An electrochemical device, characterized by, An electrode assembly as claimed in any one of claims 1-19.

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