ELECTROCHEMICAL DEVICE AND ELECTRIC DEVICE

An electrochemical device includes an electrode assembly and an insulator. The electrode assembly includes a first electrode plate, a second electrode plate and a separator. The first electrode plate includes a first current collector and a first active material layer. The first active material layer is provided with a first connecting edge. A first blank foil region is provided on a first surface of the first electrode plate. The insulator covers a part of the first active material layer and a part of the first blank foil region, respectively.

TECHNICAL FIELD

This application relates to the technical field of batteries, and in particular, to an electrochemical apparatus and an electric device.

BACKGROUND

An electrochemical device is an device that converts energy from the outside into electrical energy and stores it inside in order to supply power to external device (e.g., portable electronic device) at moments of need. Generally, the electrochemical device includes a housing, an electrode assembly accommodated in the housing, an electrolyte, and a tab connected to the electrode assembly. The electrode assembly includes a first electrode plate and a second electrode plate that are spaced apart and have opposite polarities, as well as a separator disposed between the first electrode plate and the second electrode plate.

At present, in order to ensure that the electrochemical device has a relatively high energy density, manufacturers generally provide an active material layer on an inner surface of an outermost current collector, and provide no active material layer on an outer surface to form a blank foil region, so as to avoid the waste of cost and reduction of energy density due to non-participation of an active material on the outer surface in a reaction. For ease of illustration, the electrode plate with an end on the outermost circle of the electrode assembly is hereinafter defined as the first electrode plate and the other electrode plate as the second electrode plate.

For safety reasons, it is usually necessary to provide an insulating adhesive film between the active material layer and the blank foil region to prevent a short circuit between the first electrode plate and the second electrode plate due to contact, which affects the safety of the electrochemical device. However, the insulating adhesive film will cover part of the active material layer, which reduces the capacity and energy density of the electrochemical device.

SUMMARY

This application aims to provide an electrochemical device and an electric device, which can reduce an area of a first active material layer covered by an original insulator, and effectively increase an effective area of the first active material layer in a first electrode plate, thereby increasing an energy density of the electrochemical device.

This application adopts the following technical solution to solve the technical problem thereof:

An electrochemical device includes an electrode assembly and an insulator. The electrode assembly is formed by winding a first electrode plate, a second electrode plate and a separator that are stacked, the separator is disposed between the first electrode plate and the second electrode plate, the first electrode plate includes a first current collector and a first active material layer, and a first surface of the first current collector includes a first coated region coated with the first active material layer and a first blank foil region not coated with the first active material layer in a first direction. The first surface is disposed away from a winding center of the electrode assembly, and the first direction is a direction in which a length edge extends after the first electrode plate is unwound; and the first active material layer is provided with a first side edge and a second side edge that are oppositely disposed in the first direction, as well as a third side edge and a fourth side edge that are oppositely disposed in a second direction, and the first side edge and the third side edge are connected through a first connecting edge, where the second direction is a direction in which a width edge extends after the first electrode plate is unwound. The electrochemical device further includes an insulator, the insulator includes a base portion and a first extending portion, the base portion is provided with a first end and a second end that are oppositely disposed along the first direction, the first end is disposed on the first blank foil region, the second end is disposed on the first active material layer, and the base portion covers the first side edge; and the first extending portion extends in a direction away from the first end from the second end, the first extending portion at least partially covers the first connecting edge, the insulator completely covers the first connecting edge and the first side edge, and in the first direction, a maximum distance from a side of the first extending portion away from the second end to the first side edge is greater than a maximum distance from the second end to the first side edge.

In some embodiments, in the second direction (or in a direction of pointing from the third side edge to the fourth side edge), a distance from the side of the first extending portion away from the second end to the first side edge gradually decreases (or an outer contour of the first extending portion gradually shrinks).

In some embodiments, the first connecting edge has an arc shape, and a radius R1of the first connecting edge satisfies: R1≥1 mm.

In some embodiments, in the first direction, a distance D1from a side of the first extending portion away from the first end to the first side edge satisfies: 1.2 mm≤D1≤6 mm.

In some embodiments, the insulator is provided with a second connecting edge, the second connecting edge connects the first extending portion to the base portion, and a minimum distance D2between the second connecting edge and the first connecting edge satisfies: 0.2 mm≤D2≤2 mm.

In some embodiments, a minimum distance D3between the second end and the first side edge satisfies: 0.2 mm≤D3≤2 mm.

In some embodiments, the first side edge and the fourth side edge are connected through a third connecting edge, the third connecting edge has an arc shape, and a radius R2of the third connecting edge satisfies: R2≥1 mm.

In some embodiments, the insulator further includes a second extending portion and a fourth connecting edge, the second extending portion extends in a direction away from the first end from the second end, the fourth connecting edge connects the second extending portion to the base portion, the second extending portion at least partially covers the third connecting edge, the insulator completely covers the first side edge and the third connecting edge, and in the first direction, a maximum distance from a side of the second extending portion away from the second end to the first side edge is greater than a maximum distance from the second end to the first side edge.

In some embodiments, in the second direction (or in a direction of pointing from the fourth side edge to the third side edge), a distance from the side of the second extending portion away from the second end to the first side edge gradually decreases (or an outer contour of the second extending portion gradually shrinks).

In some embodiments, in the first direction, a distance D4from a side of the second extending portion away from the first end to the first side edge satisfies: 1.2 mm≤D4≤6 mm; and a minimum distance D5between the fourth connecting edge and the third connecting edge satisfies: D5≥0.2 mm.

In some embodiments, the first electrode plate is a negative electrode plate, and the second electrode plate is a positive electrode plate; and a second tail end of the second electrode plate is located between the second end of the base portion and the first end, the first electrode plate provided with the first blank foil region is wound on an outer side of the second electrode plate, and in a winding direction of the electrode assembly, the second tail end of the second electrode plate protrudes from a first tail end of the first electrode plate, where the first tail end and the second tail end are winding completed ends of the first electrode plate and the second electrode plate at the electrode assembly, respectively.

This application further provides an electric device according to another embodiment. The electric device includes the above electrochemical device, and the electrochemical device is configured to supply electric energy to the electric device.

Compared with a current electrochemical device on the market, the electrochemical device according to the embodiment of this application has the beneficial effects that through the above configuration, the insulator reduces the area of the first active material layer covered by the base portion while completely and reliably covering the first connecting edge, which effectively increases the effective area of the first active material layer in the first electrode plate, thereby increasing the energy density of the electrochemical device.

DETAILED DESCRIPTION

For ease of understanding this application, this application is described in more detail below in conjunction with drawings and specific embodiments. It is hereby noted that when one component is expressed as being “fixed to”, “disposed on” or “fixedly connected to” another component, it may be directly on the another component, or there may be one or more components therebetween. When one component is expressed as being “connected” to another component, it may be directly connected to the another component, or there may also be one or more components therebetween. The terms “vertical”, “horizontal”, “left”, “right”, “internal”, “external” and similar expressions used in the description are merely for the purpose of illustration.

In the description, the “mounting” includes fixing or limiting a component or device to a specific position or place by welding, screwing, clamping, gluing, etc. The component or device may remain still in the specific position or place or may move within a limited range, and the component or device may or may not be dismounted after being fixed or limited to the specific position or place, which is not limited in the embodiments of this application. In addition, technical features involved in the different embodiments of this application described below may be mutually combined as long as they do not conflict with each other.

Referring toFIG.1, an electrochemical device100includes an electrode assembly10, an insulator20, a housing30and an electrolyte40. The housing30is provided with an accommodation cavity that is filled with the electrolyte40, the insulator20is disposed in the electrode assembly10and accommodated in the accommodation cavity together with the electrode assembly10, and the electrolyte40completely immerses the electrode assembly10and provides a liquid environment for a chemical reaction of the electrode assembly10.

It is worth noting that the electrochemical device100may be a pouch-type battery. That is, the housing30is prepared from a flexible material, such as an aluminum-plastic film or a steel-plastic film. The electrochemical device100may also be a hard-case battery. The housing30is prepared from a hard material, such as an aluminum housing material, a steel housing material, a high-hardness plastic material or other metal materials.

The electrode assembly10includes a first electrode plate11, a second electrode plate12and a separator13. The first electrode plate11is provided with a first head end11sand a first tail end11w, and the second electrode plate12is provided with a second head end12sand a second tail end12w. The first electrode plate11, the separator13and the second electrode plate12are sequentially stacked, and wound from the first head end11sand the second head end12sto form the electrode assembly10. In this embodiment, the first electrode plate11is a negative electrode plate, and the second electrode plate12is a positive electrode plate. After the completion of winding, an outermost layer is the first electrode plate11. In a winding direction, the second head end12sprotrudes from the first head end11s, and the second tail end12wprotrudes from the first tail end11w, thereby ensuring that lithium cobalt oxide deintercalated from the first electrode plate11can be intercalated into the second electrode plate12, and preventing lithium plating of the electrochemical device100, which affects the safety of the electrochemical device100.

As for the above first electrode plate11, reference is made toFIG.2toFIG.4. A direction in which a length edge extends after the first electrode plate11is unwound is defined as a first direction X, and a direction in which a width edge extends after the first electrode plate11is unwound is defined as a second direction Y, where the first direction X and the second direction Y are perpendicular to each other. The first electrode plate11includes a first current collector111, a first active material layer112, a first insulating material layer113and a plurality of first tabs114. A surface of the first current collector111is coated with the first active material layer112and the first insulating material layer113. The first active material layer112chemically reacts with the second electrode plate12through the electrolyte40. The first insulating material layer113isolates the first electrode plate11from being in contact with the second electrode plate12to reduce the risk of a short circuit. The plurality of tabs114are all connected to the length edge of the first electrode plate11and are disposed at intervals in the first direction X, and each of the first tabs114extends in the second direction Y.

The first current collector111is provided with a first surface111aand a second surface111bthat are oppositely disposed, where the first surface111ais oriented away from a winding center of the electrode assembly10, and the second surface111bis close to the winding center of the electrode assembly10. In the first direction X, the first surface111aof the first current collector111is adjacently provided with a first coated region1111and a first blank foil region1112in sequence, the first coating region1111is configured to be coated with the first active material layer112, and the first blank foil region1112is not treated. In the second direction Y, the first surface111aof the first current collector111is adjacently provided with the first coated region1111and a second blank foil region1113in sequence, and the second blank foil region1113is configured to be coated with the first insulating material layer113. In the second direction Y, the second surface111bof the first current collector111is adjacently coated with the first active material layer112and the first insulating material layer113in sequence. The first insulating material layer113may include some existing commonly used inorganic materials or insulating organic materials, and the inorganic materials may include aluminum oxide, magnesium oxide, zirconium oxide and the like; and the first insulating material layer113may further include a commonly used binder, such as polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride, polymethyl methacrylate, polyphenylene ether, polypropylene carbonate, polyethylene oxide and a derivative thereof.

The first active material layer112with which the first coating region1111is coated is provided with a first side edge1121, a second side edge1122, a third side edge1123, a fourth side edge1124and a first connecting edge1125. The first side edge1121and the second side edge1122are oppositely disposed in the first direction X, the third side edge1123and the fourth side edge1124are oppositely disposed in the second direction Y, and the two ends of the first connecting edge1125are tangent to the first side edge1121and the third side edge1123respectively and smoothly connected. An extension line of the first side edge1121and an extension line of the third side edge1123intersect at a point A. The first connecting edge1125has a circular arc shape, and a protruding portion of a circular arc approaches to the point A. A radius R1of the first connecting edge1125satisfies: R1≥1 mm. The extension line of the first side edge1121, the extension line of the third side edge1123and the first connecting edge1125close in to form a first vacant region1114together, and the first vacant region1114is not coated with any coating.

In the embodiment, referring toFIG.8, a method for measuring the radius R1of the first connecting edge1125is as follows. In the first direction X, there is an interface separation point P (i.e., a tangent point of the third side edge1123and the first connecting edge1125) of the first insulating material layer113and the first active material layer112, and a distance from the separation point P to the first side edge is the radius R1of the first connecting edge1125.

As for the above second electrode plate12, reference is made toFIG.5andFIG.6. The second electrode plate12includes a second current collector121, a second active material layer122and a plurality of second tabs123. The plurality of second tabs123are all connected to a length edge of the second current collector121, and in a direction in which the length edge extends after the second electrode plate12is unwound, the plurality of second tabs123are disposed at intervals and extend in a direction perpendicular to the length edge. The second current collector121is provided with a third surface121aand a fourth surface121bthat are oppositely disposed, where the third surface121ais oriented away from the winding center of the electrode assembly10, and the fourth surface121bis close to the winding center of the electrode assembly10. The third surface121ais coated with the second active material layer122, the fourth surface121bis coated with the second active material layer122, and a position of the fourth surface121bclose to the second head end12sis not coated with the second active material layer122. The second active material layer122is configured to chemically react with the first active material layer112.

When the first electrode plate11, the second electrode plate12and the separator13are stacked and wound to form the electrode assembly10, the plurality of the first tabs114are sequentially stacked to form one electrode of the electrode assembly10, and the plurality of second tabs123are sequentially stacked to form the other electrode of the electrode assembly10.

In some embodiments, the first electrode plate11is a negative electrode plate, and the second electrode plate12is a positive electrode plate.

In some embodiments, the first current collector111is an aluminum foil, and the second current collector121is a copper foil.

In some embodiments, the first insulating material layer113may be an inorganic particle layer, such as a ceramic coating.

In some embodiments, the first tabs114and the first current collector111are of an integrally formed structure, that is, the first tabs114are formed by cutting the first current collector111; and the second tabs123and the second current collector121are of an integrally formed structure, that is, the second tabs123are formed by cutting the second current collector121. In some other embodiments, the first tabs114are welded or bonded to the first current collector111; and the second tabs123are welded or bonded to the second current collector121.

As for the above insulator20, reference is made toFIG.7. The insulator20includes a base portion21, a first extending portion22and a second connecting edge24. In the first direction X, the base portion21is provided with a first end211and a second end212. The first end211is disposed in the first blank foil region1112, the second end212is disposed on the first active material layer112, and the base portion21covers the first side edge1121of the first active material layer112. The first extending portion22extends in a direction away from the first end211from the second end212, and the first extending portion22covers part of the first side edge1121, part of the third side edge1123and all of the first connecting edge1125of the first active material layer112. In an embodiment, the base portion21completely covers the first side edge1121of the first active material layer112, and the first extending portion22at least partially covers the first connecting edge1125. The separator13generally has a thickness of 4 μm to 5 μm, and thus is poor in mechanical property and compactness, while the insulator20has a thickness of 14 μm to 16 μm, and thus is good in mechanical property and compactness, and when the first extending portion22completely covers the first vacant region1114, an aluminum-positive electrode short circuit reaction of the first current collector111can be prevented when the separator13between the first electrode plate11and the second electrode plate12is broken, thereby improving safety performance of the electrochemical device100. The second connecting edge24is configured to smoothly connect a side of the first extending portion22away from the first end211to the second end212to prevent a sudden-change connection point at a junction of the first extending portion22and the base portion21, and the insulator20is prone to a phenomenon of stress concentration at the sudden-change connection point, and is torn inwards from the sudden-change connection point to break the insulator20, which affects the safety performance of the electrochemical device100. In the second direction Y (or in a direction of pointing from the third side edge1123of the first active material layer112to the fourth side edge1124), a distance from a side of the first extending portion22away from the second end212to the first side edge1121gradually decreases (or an outer contour of the first extending portion22gradually shrinks).

Referring toFIG.8, in the first direction X, a distance D1from the side of the first extending portion22of the insulator20away from the first end211to the first side edge1121of the first active material layer112satisfies: 1.2 mm≤ D1≤6 mm. In the mass production process of the first electrode plate11, when the first coated region1111of the first current collector111is coated with the first active material layer112, the radius R1of the first connecting edge1125of the first active material layer112can only be controlled at a minimum of 1 mm due to the influence of an existing coating tool and coating process technology. Therefore, in the embodiment, in order to ensure that the first extending portion22of the insulator20can completely and reliably cover the first vacant region1114, the distance D1from the side of the first extending portion22of the insulator20away from the first end211to the first side edge1121of the first active material layer112is at least greater than or equal to 1.2 mm.

In the embodiment, a method for measuring the distance D1from the side of the first extending portion22of the insulator20away from the first end211to the first side edge1121of the first active material layer112is as follows. An extension line of the side (one point) of the first extending portion22of the insulator20away from the first end211is made in the second direction Y, an extension line of the first side edge1121is made in the second direction Y, and a distance between the two extension lines in the first direction X is the distance D1. The similar method may also be used for measuring other distances mentioned herein, such as D2.

A minimum distance D2between the second connecting edge24of the insulator20and the first connecting edge1125of the first active material layer112satisfies: 0.2 mm≤D2≤2 mm. In the process of disposing the insulator20on the first electrode plate11, in order to ensure that the insulator20can completely and reliably cover the first vacant region1114, in combination with a tolerance of an existing process technology, the insulator20can reliably and snugly fit onto the first active material layer112only when the minimum distance D2between the second connecting edge24of the insulator20and the first connecting edge1125of the first active material layer112is at least greater than or equal to 0.2 mm.

In the first direction X, a minimum distance D3between the second end212of the insulator20and the first side edge1121of the first active material layer112satisfies: 0.2 mm≤D3≤2 mm. In the process of disposing the insulator20on the first electrode plate11, in order to ensure that the insulator20can completely and reliably cover the first side edge1121of the first active material layer112, in combination with a tolerance of an existing process technology, the insulator20can reliably and snugly fit onto the first active material layer112only when the minimum distance D3between the second end212of the insulator20and the first side edge1121of the first active material layer112is at least greater than or equal to 0.2 mm. In addition, the minimum distance D2between the second connecting edge24of the insulator20and the first connecting edge1125of the first active material layer112and the minimum distance D3between the second end212of the insulator20and the first side edge1121of the first active material layer112also need to be controlled within a reasonable range. When the minimum distance D2and the minimum distance D3are unduly large, an area of the first active material layer112covered by the insulator20is unduly large, thus affecting an effective reaction area between the first electrode plate11and the second electrode plate12, and reducing the capacity and energy density of the electrochemical device100.

In the embodiment, the second connecting edge24of the insulator20has a circular arc shape, and an arc protruding direction of the second connecting edge24is identical to an arc protruding direction of the first connecting edge1125, that is, a center of a circle where the first connecting edge1125is located coincides with a circle of a center where the second connecting edge24is located, and the second connecting edge24and the first connecting edge1125are of a ring structure. In the ring structure, a distance between the first connecting edge1125and the second connecting edge24remains the same, such that the insulator20covers a minimum area of the first active material layer112while completely and reliably covering the first vacant region1114, which is conducive to increasing the capacity of the electrochemical device100, thereby increasing the energy density of the electrochemical device100.

In some other embodiments, referring toFIG.9andFIG.10, the second connecting edge24of the insulator20may have other shapes, provided that the first extending portion22of the insulator20can completely and reliably cover the first vacant region1114, e.g., a circular arc shape, an arc protruding portion of which is disposed opposite to an arc protruding portion of the first connecting edge1125, or a straight line shape, a straight line of which directly connects the first extending portion22to the second end212.

In some embodiments, the first extending portion22of the insulator20covers part of the first connecting edge1125, and the base portion21of the insulator20covers the rest of the first connecting edge1125and all of the first side edge1121.

In some embodiments, referring toFIG.11, the first active material layer112coating the first coated region1111further includes a third connecting edge1126, and the two ends of the third connecting edge1126are tangent to the first side edge1121and the fourth side edge1124respectively and smoothly connected. An extension line of the first side edge1121and an extension line of the fourth side edge1124intersect at a point B. The third connecting edge1126has a circular arc shape, and a protruding portion of a circular arc approaches to the point B. A radius R2of the third connecting edge1126satisfies: R2≥1 mm. The extension line of the first side edge1121, the extension line of the fourth side edge1124and the third connecting edge1126close in to form a second vacant region1115together, and the second vacant region1115is not coated with any coating.

The insulator20further includes a second extending portion23and a fourth connecting edge25. The second extending portion23extends away from the first end211of the base portion21from the second end212of the base portion21. The second extending portion23covers part of the first side edge1121, part of the fourth side edge1124and all of the third connecting edge1126of the first active material layer112. That is, the second extending portion23completely covers the second vacant region1115to prevent a positive electrode reaction phenomenon of the first current collector111when the separator13between the first electrode plate11and the second electrode plate12is broken, thereby improving safety performance of the electrochemical device100. The second extending portion23may further partially cover the third connecting edge1126, and the base portion21completely covers the first side edge1121and part of the third connecting edge1126, that is, the base portion21and the second extending portion23covers the second vacant region1115together. The fourth connecting edge25is configured to smoothly connect a side of the second extending portion23away from the first end211to the second end212to prevent a sudden-change connection point at a junction of the second extending portion23and the base portion21, and the insulator20is prone to a phenomenon of stress concentration at the sudden-change connection point, and is torn inwards from the sudden-change connection point to break the insulator20, which affects the safety performance of the electrochemical device100. In the second direction Y (or in a direction of pointing from the fourth side edge1124of the first active material layer112to the third side edge1123), a distance from a side of the second extending portion23away from the second end212to the first side edge1121gradually decreases (or an outer contour of the second extending portion23gradually shrinks). In the first direction X, a maximum distance from the side of the second extending portion23away from the second end212to the first side edge1121is greater than a maximum distance from the second end212to the first side edge1121.

In the first direction, a distance D4from a side of the second extending portion23of the insulator20away from the first end211to the first side edge1121of the first active material layer112satisfies: 1.2 mm≤D4≤6 mm.

A minimum distance D5between the fourth connecting edge25of the insulator20and the third connecting edge1126of the first active material layer112satisfies: 0.2 mm≤D5≤2 mm.

It is worth noting that in some embodiments, the extend to which the first extending portion22and the base portion21cover the first side edge1121and the first connecting edge1125may be appropriately adjusted according to actual needs. For example, the first extending portion22partially covers the first connecting edge1125, and the base portion21covers the rest of the first connecting edge1125and the first side edge1121; or, the base portion21covers part of the first side edge1121, and the first extending portion22covers the rest of the first side edge1121and the first connecting edge1125; or, the first extending portion22completely covers the first connecting edge1125, and the base portion21completely covers the first side edge1121, or the like, provided that the base portion21and the first extending portion22cooperate to completely cover the first vacant region1114. Similarly, the above covering rule is also applicable to the second extending portion23and the base portion21, provided that the base portion21and the second extending portion23cooperate to completely cover the second vacant region1115.

In order to facilitate readers to better understand the technical solution of this application, the first electrode plate11, the second electrode plate12and the separator13(not shown in the drawing) in the electrode assembly10are simplified. Referring toFIG.12andFIG.13, in this embodiment, the first active material layer112is lithium cobalt oxide, and the second active material layer122is graphite. After the first electrode plate11, the second electrode plate12and the separator13are sequentially stacked and wound to form the electrode assembly10, the second tail end12wof the second electrode plate12is ended between the second end212and the first end21of the base portion21in the insulator20, and preferably, the second tail end12wof the second electrode plate12is ended between the second end212of the base portion21and the first side edge1121of the first active material layer112, which can reduce a graphite coating not participating in a chemical reaction in the second electrode plate12, reduce a manufacturing cost, and increase a reaction rate between the lithium cobalt oxide of the first electrode plate11and the graphite of the second electrode plate12. The first electrode plate11provided with the first blank foil region1112continues being wound on the outer side of the second electrode plate12, and in a winding direction of the electrode assembly10, the second tail end12wof the second electrode plate12protrudes from the first tail end11wof the first electrode plate11, which ensures that the second electrode plate12has a sufficient graphite coating for the lithium cobalt oxide deintercalated from the first electrode plate11to be intercalated, reduces the probability of a lithium plating phenomenon of the electrode assembly10, and improves the safety of the electrochemical device100.

The electrochemical device100according to the embodiment of this application has the following beneficial effects. The electrochemical device100includes the electrode assembly10and the insulator20. The electrode assembly10is formed by winding the first electrode plate11, the second electrode plate12and the separator13that are stacked. The first electrode plate11includes the first current collector111and the first active material layer112. The first surface111aof the first current collector111is provided with the first coated region1111and the first blank foil region1112. The first active material layer112is disposed in the first coated region1111. The first active material layer112is provided with the first side edge1121and the second side edge1122that are oppositely disposed in the first direction X, as well as the third side edge1123and the fourth side edge1124that are oppositely disposed in the second direction Y. The first side edge1121and the third side edge1123are connected through the first connecting edge1125. The insulator20includes the base portion21and the first extending portion22. In the first direction X, the base portion21is provided with the first end211and the second end212. The base portion21of the insulator20covers the first side edge1121of the first active material layer112, and the first extending portion22of the insulator20covers the first connecting edge1125. In the direction of pointing from the third side edge1123to the fourth side edge1124, the outer contour of the first extending portion22gradually shrinks, where the first direction X is the direction in which the length edge extends after the first electrode plate11is unwound, and the second direction Y is the direction in which the width edge extends after the first electrode plate11is unwound. Through the above configuration, the insulator20reduces the area of the first active material layer112covered by the base portion21while completely and reliably covering the first connecting edge1125, and effectively increases the effective area of the first active material layer112in the first electrode plate11, thereby increasing the energy density of the electrochemical device100.

Based on the same inventive concept, the embodiment of this application further provides an electric device, including the electrochemical device100. Reference is made to the above embodiment for the specific structure and function of the electrochemical device100, details of which are omitted here. The electric device may be a mobile phone, a tablet computer, a computer, an unmanned aerial vehicle, or the like that needs to be driven by electricity.

Finally, it is hereby noted that the foregoing embodiments are merely intended to illustrate technical solutions of this application rather than to limit this application; under the thought of this application, technical features in the foregoing embodiments or different embodiments may also be combined, steps may be implemented in any orders, and there are many other changes in different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application is illustrated in detail with reference to the foregoing embodiments, a person of ordinary skill in the art understands that he may still make modifications to the technical solutions recited in the foregoing embodiments or make equivalent replacements to some of the technical features; however, these modifications or replacements do not make the essence of the corresponding technical solution depart from the scope of the technical solutions of the embodiments.