Winding type battery cell and electrochemical device

Abstract

The embodiment of the invention relates to a winding type battery cell and an electrochemical device. According to one embodiment, the winding type battery cell comprises a first pole piece, a second pole piece, an isolating membrane, a central area enclosed by the first pole piece, the second pole piece and the isolating membrane, and a thickness direction. And the first pole piece, the second pole piece and the isolating membrane are wound to form a wound battery cell. The first pole piece comprises a first current collector with a first surface and a second surface opposite to the first surface, and the first surface is closer to the central area relative to the second surface; the first section is provided with a first end and a second end, and the first end is a winding starting end of the first pole piece; the planar second section is provided with a third end and a fourth end, and a first tab is arranged on the first surface of the second section. The second pole piece comprises a second tab of which the first side is arranged on the second pole piece; and the first end, the first tab and the second tab are not overlapped in the thickness direction. The winding type battery cell and the electrochemical device provided by the embodiment of the invention have relatively high space utilization rate and energy density.

Description

[0001] This application is a divisional application of a patent application with an application date of March 12, 2020, application number 202080005204.8, and name “Wound Battery Cell and Electrochemical Device”. Technical Field

[0002] The embodiments of the present application relate to the field of batteries, and in particular to wound battery cells and electrochemical devices. Background Art

[0003] Batteries have been widely used in various electronic products and electric vehicles. However, with the development of battery commercialization, the market has higher and higher requirements for the energy density of batteries. Therefore, the industry needs a wound battery cell and electrochemical device with higher energy density. Summary of the invention

[0004] One of the purposes of the embodiments of the present application is to provide a wound battery cell and an electrochemical device, which can reduce the thickness of the wound battery cell and have higher energy density and space utilization.

[0005] According to an embodiment of the present application, a wound battery cell is provided, which includes a first pole piece, a second pole piece and a separator, the separator is arranged between the first pole piece and the second pole piece, and the first pole piece, the second pole piece and the separator are wound to form the wound battery cell; the wound battery cell has a thickness direction and a central area enclosed by the first pole piece, the second pole piece and the separator; the first pole piece includes: a first current collector, the first current collector includes: a first surface and a second surface opposite to the first surface, the first surface is closer to the central area than the second surface; a first section, the first section has a first end and a second end, the first end is the winding starting end of the first pole piece; and a second section, the second section has a third end and a fourth end, the third end is connected to the second end; the second section is planar, and the first surface of the second section is provided with a first pole ear; the second pole piece includes: a second pole ear, the second pole ear has a first side and a second side opposite to the first side, the first side is provided on the second pole piece; wherein the first end, the first pole ear and the second pole ear do not overlap in the thickness direction.

[0006] In some embodiments of the present application, the isolation membrane has a fifth end and a sixth end, the fifth end is the starting end of the winding of the isolation membrane, and the sixth end is the ending end of the winding of the isolation membrane, and the fifth end does not overlap with the first end, the first pole ear and the second pole ear in the thickness direction.

[0007] In some embodiments of the present application, the sixth end does not overlap with the first electrode tab and the second electrode tab in the thickness direction.

[0008] In some embodiments of the present application, the isolation membrane has a first dividing line, and the first dividing line to the fifth end constitute a first part of the isolation membrane, the shape of the first part is curved or planar, and the first part does not overlap with the first pole ear and the second pole ear in the thickness direction.

[0009] In some embodiments of the present application, a first insulating colloid is further included, which covers the winding end of the second pole piece, and the first insulating colloid does not overlap with the first pole lug and the second pole lug in the thickness direction.

[0010] In some embodiments of the present application, the winding end of the second pole piece does not overlap with the first pole tab and the second pole tab in the thickness direction.

[0011] In some embodiments of the present application, the first surface and the second surface of the first section are not provided with the first active material layer; the first surface of the second section is not provided with the first active material layer, and the second surface of the second section is provided with the first active material layer.

[0012] In some embodiments of the present application, the first pole piece also includes: a third segment and a fourth segment, wherein the third segment has a seventh end and an eighth end, and the seventh end is connected to the fourth end; the fourth segment has a ninth end and a tenth end, and the ninth end is connected to the eighth end, and the tenth end is the winding end of the first pole piece; and wherein the first surface of the third segment is not provided with the first active material layer, the second surface of the third segment is provided with the first active material layer, and the first surface and the second surface of the fourth segment are provided with the first active material layer.

[0013] In some embodiments of the present application, the isolation film between the second section and the third section has a coating or has no coating.

[0014] In some embodiments of the present application, the second pole piece includes a second current collector, and the second current collector includes: a third surface and a fourth surface opposite to the third surface, the third surface is closer to the central area than the fourth surface; the second pole piece also includes: a fifth segment, a sixth segment and a seventh segment, wherein the fifth segment has an eleventh end and a twelfth end, and the eleventh end is the starting end of the winding of the second pole piece; the sixth segment has a thirteenth end and a fourteenth end, and the thirteenth end is connected to the twelfth end; the seventh segment has a fifteenth end and a sixteenth end, and the fifteenth end is connected to the fourteenth end, and the sixteenth end is the ending end of the winding of the second pole piece; and wherein the third surface and the fourth surface of the fifth segment are provided with a second active material layer; the third surface of the sixth segment is provided with the second active material layer; the third surface of the seventh segment is not provided with the second active material layer.

[0015] In some embodiments of the present application, the fifth segment includes a first segment, a second segment, a third segment, a fourth segment and a fifth segment, wherein the first segment, the third segment and the fifth segment are planar, the second segment and the fourth segment are curved, the first segment is the starting segment of the fifth segment, the second segment is connected to the first segment, the third segment is connected to the second segment, the fourth segment is connected to the third segment, and the fifth segment is the ending segment of the fifth segment; the sixth segment includes a sixth segment, a seventh segment, an eighth segment and a ninth segment, wherein the sixth segment and the eighth segment are curved, the seventh segment and the ninth segment are planar, the sixth segment is the starting segment of the sixth segment, the seventh segment is connected to the sixth segment, and the eighth segment is connected to the The seventh segment is connected to the ninth segment, the ninth segment is connected to the eighth segment, and the ninth segment is the ending segment of the sixth segment; the seventh segment includes the tenth segment and the eleventh segment, wherein the tenth segment is curved, the eleventh segment is planar, the tenth segment is the starting segment of the seventh segment, and the eleventh segment is the ending segment of the seventh segment; wherein the fourth surface of the sixth segment is provided with a second insulating colloid, the starting end and the ending end of the second insulating colloid respectively coincide with the starting end and the ending end of the sixth segment, and the starting end of the sixth segment is connected to the fifth segment; the third surface of the tenth segment is provided with a third insulating colloid, the starting end and the ending end of the third insulating colloid respectively coincide with the starting end and the ending end of the tenth segment, and the starting end of the tenth segment is connected to the sixth segment.

[0016] In some embodiments of the present application, the sixth end exceeds the end ends of the second insulating colloid and the third insulating colloid, or the sixth end is flush with the end ends of the second insulating colloid and the third insulating colloid.

[0017] In some embodiments of the present application, the first side of the second pole tab is disposed on the third surface of the eleventh segment.

[0018] In some embodiments of the present application, the first side of the second pole tab is disposed on the fourth surface of the seventh segment.

[0019] In some embodiments of the present application, the wound battery cell further includes a fourth insulating colloid covering the second side of the second electrode tab.

[0020] In some embodiments of the present application, the first insulating colloid covers the second side of the second electrode tab.

[0021] In some embodiments of the present application, the second pole tab is located below the eleventh segment.

[0022] In some embodiments of the present application, the third segment has a first part, the third surface and the fourth surface of the first part are not provided with the second active material layer, and the first side of the second pole ear is provided on one of the third surface and the fourth surface of the first part; or, the fifth segment has a second part, the third surface and the fourth surface of the second part are not provided with the second active material layer, and the first side of the second pole ear is provided on one of the third surface and the fourth surface of the second part; the wound battery cell also includes: a fifth insulating colloid, which is provided on the second side of the second pole ear and shields the corresponding surface of the first part or the second part to which the second side of the second pole ear is connected; and a sixth insulating colloid, which is opposite to the fifth insulating colloid and shields the surface of the first part that is not connected to the first side of the second pole ear or the surface of the second part that is not connected to the first side of the second pole ear.

[0023] In some embodiments of the present application, a seventh insulating layer is further included, which is disposed at a corresponding position of the first pole piece opposite to the fifth insulating colloid and the sixth insulating colloid.

[0024] According to another embodiment of the present application, an electrochemical device is provided, which includes the wound battery cell described in any of the above embodiments.

[0025] The wound battery cell and electrochemical device provided in the embodiments of the present application have a smaller thickness than the existing wound battery cells, and have higher energy density and space utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The following will briefly describe the drawings necessary for describing the embodiments of the present application or the prior art to facilitate the description of the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, without the need for creative work, drawings of other embodiments can still be obtained based on the structures illustrated in these drawings.

[0027] Figure 1A A cross-sectional schematic diagram of a wound battery cell according to an embodiment of the present application is shown;

[0028] Figure 1B A cross-sectional schematic diagram of a wound battery cell according to another embodiment of the present application is shown;

[0029] Figure 1C A cross-sectional schematic diagram of a wound battery cell according to another embodiment of the present application is shown;

[0030] Figure 1D A cross-sectional schematic diagram of a wound battery cell according to another embodiment of the present application is shown;

[0031] Figure 1E A cross-sectional schematic diagram of a wound battery cell according to another embodiment of the present application is shown;

[0032] Figure 1F A cross-sectional schematic diagram of a wound battery cell according to another embodiment of the present application is shown;

[0033] Figure 1G A cross-sectional schematic diagram of a wound battery cell according to another embodiment of the present application is shown;

[0034] Figure 1H A cross-sectional schematic diagram of a wound battery cell according to another embodiment of the present application is shown;

[0035] Fig. 1I A cross-sectional schematic diagram of a wound battery cell according to another embodiment of the present application is shown;

[0036] Figure 1J A cross-sectional schematic diagram of a wound battery cell according to another embodiment of the present application is shown;

[0037] Figure 1K A cross-sectional schematic diagram of a wound battery cell according to another embodiment of the present application is shown;

[0038] Figure 1L A cross-sectional schematic diagram of a wound battery cell according to another embodiment of the present application is shown;

[0039] Figure 1M A cross-sectional schematic diagram of a wound battery cell according to another embodiment of the present application is shown;

[0040] Figure 1N A cross-sectional schematic diagram of a wound battery cell according to another embodiment of the present application is shown. DETAILED DESCRIPTION

[0041] The embodiments of the present application will be described in detail below. In the full text of the present application specification, the same or similar components and components with the same or similar functions are represented by similar reference numerals. The embodiments of the accompanying drawings described herein are illustrative, graphical, and are used to provide a basic understanding of the present application. The embodiments of the present application should not be construed as limiting the present application.

[0042] In this specification, unless otherwise specified or limited, relative terms such as "central", "longitudinal", "lateral", "front", "rear", "right", "left", "inner", "outer", "lower", "higher", "horizontal", "vertical", "above", "below", "above", "below", "top", "bottom" and their derivative terms (such as "horizontally", "downwardly", "upwardly", etc.) should be interpreted as referring to the directions described in the discussion or depicted in the drawings. These relative terms are only used for convenience of description and do not require that the present application be constructed or operated in a specific direction.

[0043] As used herein, the terms "about," "approximately," "substantially," "substantially," and "approximately" are used to describe and illustrate small variations. When used in conjunction with an event or circumstance, the terms may refer to instances where the event or circumstance occurred exactly as well as instances where the event or circumstance occurred very approximately. For example, when used in conjunction with a numerical value, the terms may refer to a range of variation less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. For example, two values ​​may be considered “substantially” the same if the difference between them is less than or equal to ±10% of the mean of the values ​​(e.g., less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%).

[0044] Furthermore, for ease of description, “first”, “second”, “third”, etc. may be used herein to distinguish different components in one figure or a series of figures. “First”, “second”, “third”, etc. are not intended to describe the corresponding components.

[0045] In the present application, unless otherwise specified or limited, the terms "set", "connect", "couple", "fixed" and similar terms are used broadly, and those skilled in the art can understand that the above terms can be, for example, fixed connection, detachable connection or integrated connection according to the specific circumstances; it can also be a mechanical connection or an electrical connection; it can also be a direct connection or an indirect connection through an intermediate structure; it can also be an internal communication between two components.

[0046] In the detailed description and claims, a list of items connected by the terms "one of," "one of," "a kind of," or other similar terms may mean any of the listed items. For example, if items A and B are listed, the phrase "one of A and B" means only A or only B. In another example, if items A, B, and C are listed, the phrase "one of A, B, and C" means only A; only B; or only C. Item A may include a single element or multiple elements. Item B may include a single element or multiple elements. Item C may include a single element or multiple elements.

[0047] In the detailed description and claims, a list of items connected by the terms "at least one of," "at least one of," "at least one of," or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may include a single element or multiple elements. Item B may include a single element or multiple elements. Item C may include a single element or multiple elements.

[0048] When the prior art forms a wound battery cell, an empty internal isolation film is usually required, resulting in four layers of isolation film inside the wound battery cell. Therefore, the wound battery cell provided by the prior art has a low space utilization rate. The internal structure of the battery cell and the isolation film winding process can be improved to obtain a wound battery cell with only two layers of isolation film inside. However, relying solely on reducing the number of isolation film layers inside the wound battery cell to increase the space utilization rate of the battery cell is not enough to meet the market demand for higher energy density of the battery cell. Therefore, the industry needs to provide more effective technical solutions to obtain wound batteries with higher energy density and space utilization.

[0049] In view of the above situation, the embodiments of the present application provide an improved wound battery cell and electrochemical device, which, on the basis of having only two layers of isolation membranes in the central area of ​​the wound battery cell, effectively reduces the thickness of the battery cell by designing the positional relationship between the isolation membrane located in the central area of ​​the wound battery cell and the pole piece and / or the battery cell tab in the central area in the thickness direction of the battery cell, thereby improving the space utilization and energy density of the battery cell.

[0050] Figure 1A FIG. 1 shows a cross-sectional schematic diagram of a wound battery cell 10I according to an embodiment of the present application. Figure 1A As shown, a wound battery cell 10I according to an embodiment of the present application includes: a first pole sheet 100, a second pole sheet 200 and a separator 300. The first pole sheet 100, the second pole sheet 200 and the separator 300 are wound to form the wound battery cell 10I. The wound battery cell 10I has a thickness direction X, a length direction Y perpendicular to the thickness direction, and a central area S enclosed by the first pole sheet 100, the second pole sheet 200 and the separator 300.

[0051] The first pole piece 100 may include a first current collector 101. The material of the first current collector 101 may include any material suitable for a current collector in the art. The first current collector 101 may include, for example, but not limited to, a polymer layer and / or a metal layer. The first current collector 101 may include a first surface 101a and a second surface 101b opposite to the first surface 101a. The first surface 101a is closer to the central area S than the second surface 101b.

[0052] The first pole piece 100 may include a first section 103, a second section 105, a third section 107, and a fourth section 109. Each of the first section 103, the second section 105, the third section 107, and the fourth section 109 may be regarded as a part of the first current collector 101. The first section 103, the second section 105, the third section 107, and the fourth section 109 together constitute the entire first current collector 101.

[0053] The first section 103 has a first end 103a and a second end 103b. The first end 103a may be the starting end of the first section 103, that is, the winding starting end of the first pole piece 100. The second end 103b may be the ending end of the first section 103. The first surface 101a and the second surface 101b of the first section 103 may not be provided with an active material layer. That is, the portion of the first current collector 101 defined by the first section 103 may be a current collector that is not coated with any active material layer. The first section 103 may include a curved and / or planar current collector.

[0054] The second section 105 is connected to the first section 103. The second section 105 has a third end 105a and a fourth end 105b. The third end 105a may be the starting end of the second section 105 and is connected to the second end 103b. The fourth end 105b may be the ending end of the second section 105. The second section 105 may include only a planar current collector. The first surface 101a of the second section 105 may be provided with a first pole ear 111. The material of the first pole ear 111 may include a metal. In some embodiments, the material of the first pole ear 111 may include copper. In some embodiments, the material of the first pole ear 111 may include nickel. In some embodiments, the material of the first pole ear 111 may include an alloy material of nickel, silver or copper. In some embodiments, the material of the first pole ear 111 may include any material suitable for pole ears in the art. The first pole tab 111 may be connected to the first surface 101a of the second section 105 of the first current collector 101 by any suitable means, such as, but not limited to, resistance welding, ultrasonic welding, conductive adhesive connection, etc. The first pole tab 111 may be a negative pole tab. In other embodiments of the present application, the first pole tab 111 may be a positive pole tab. When the first pole tab 111 is located in the second section 105 of the first pole sheet 100, the separator 300 at the starting end of the winding does not need to be wound empty for one turn, so the central area S may have only two layers of separator 300. The first surface 101a of the second section 105 may not be provided with an active material layer, and the second surface 101b of the second section 105 may be provided with a first active material layer 113. That is, the portion of the first current collector 101 defined by the second section 105 may be a current collector with only one surface coated with an active material layer. The first active material layer 113 may include any active material layer material commonly used in the art, such as, but not limited to, silicon carbon, conductive carbon black (Super P), binder styrene butadiene rubber (SBR), or lithium cobalt oxide (LiCoO 2 ).

[0055] The third section 107 is connected to the second section 105. The third section 107 has a seventh end 107a and an eighth end 107b. The seventh end 107a may be the starting end of the third section 107 and is connected to the fourth end 105b. The eighth end 107b may be the ending end of the third section 107. The third section 107 may include a curved and planar current collector. The first surface 101a of the third section 107 may not be provided with any active material layer. The second surface 101b of the third section 107 may be provided with a first active material layer 113. That is, the portion of the first current collector 101 defined by the third section 107 may be a current collector having only one surface coated with an active material layer.

[0056] The fourth section 109 is connected to the third section 107. The fourth section 109 has a ninth end 109a and a tenth end 109b. The ninth end 109a may be the starting end of the fourth section 109 and is connected to the eighth end 107b. The tenth end 109b may be the ending end of the fourth section 109, that is, the winding ending end of the first pole piece 100. The fourth section 109 may include curved and planar current collectors. The first active material layer 113 may be provided on both the first surface 101a and the second surface 101b of the fourth section 109. That is, the portion of the first current collector 101 defined by the fourth section 109 may be a current collector with active material layers coated on both surfaces.

[0057] The second pole piece 200 may include a second current collector 201. The material of the second current collector 201 may include any material suitable for a current collector in the art. The second current collector 201 may include, for example, but not limited to, a polymer layer and / or a metal layer. The second current collector 201 may include a third surface 201a and a fourth surface 201b opposite to the third surface 201a. The third surface 201a is closer to the central area S than the fourth surface 201b.

[0058] The second pole piece 200 may include a fifth segment 203, a sixth segment 205 and a seventh segment 207. Each of the fifth segment 203, the sixth segment 205 and the seventh segment 207 may be regarded as a part of the second current collector 201. The fifth segment 203, the sixth segment 205 and the seventh segment 207 together constitute the entire second current collector 201.

[0059] The fifth section 203 has an eleventh end 203a and a twelfth end 203b. The eleventh end 203a may be the starting end of the fifth section 203, that is, the winding starting end of the second pole piece 200. The twelfth end 203b may be the ending end of the fifth section 203. The third surface 201a and the fourth surface 201b of the fifth section 203 may be provided with a second active material layer 213. That is, the portion of the second current collector 201 defined by the fifth section 203 may be a current collector with active material layers coated on both surfaces. The second active material layer 213 may include materials of any active material layer commonly used in the art, for example, but not limited to, silicon carbon, conductive carbon black (SuperP), binder styrene butadiene rubber (SBR), or lithium cobalt oxide (LiCoO2). The materials of the second active material layer 213 and the first active material layer 113 may be the same or different. The fifth section 203 may include a curved and / or planar current collector.

[0060] The fifth segment 203 may include a first segment 2031, a second segment 2033, a third segment 2035, a fourth segment 2037, and a fifth segment 2039. Each of the first segment 2031, the second segment 2033, the third segment 2035, the fourth segment 2037, and the fifth segment 2039 may be considered as a part of the fifth segment 203. The first segment 2031, the second segment 2033, the third segment 2035, the fourth segment 2037, and the fifth segment 2039 together constitute the entire fifth segment 203.

[0061] The first segment 2031 may be the starting segment of the fifth segment 203. The first segment 2031 has a starting end 2031a and an ending end 2031b. The starting end 2031a of the first segment 2031 coincides with the eleventh end 203a of the fifth segment 203. The starting end 2031a is the winding starting end of the second pole piece 200. The first segment 2031 may be planar. The second segment 2033 is connected to the first segment 2031. The second segment 2033 has a starting end 2033a and an ending end 2033b. The starting end 2033a of the second segment 2033 is connected to the ending end 2031b of the first segment 2031. The second segment 2033 may be curved. The third segment 2035 is connected to the second segment 2033. The third segment 2035 has a starting end 2035a and an ending end 2035b. The starting end 2035a of the third segment 2035 is connected to the ending end 2033b of the second segment 2033. The third segment 2035 may be in a planar shape. The fourth segment 2037 is connected to the third segment 2035. The fourth segment 2037 has a starting end 2037a and an ending end 2037b. The starting end 2037a of the fourth segment 2037 is connected to the ending end 2035b of the third segment 2035. The fourth segment 2037 may be in a curved shape. The fifth segment 2039 is connected to the fourth segment 2037. The fifth segment 2039 has a starting end 2039a and an ending end 2039b. The starting end 2039a of the fifth segment 2039 is connected to the ending end 2037b of the fourth segment 2037. The ending end 2039b overlaps with the ending end 203b of the fifth segment 203. The fifth segment 2039 is the end segment of the fifth section 203. The fifth segment 2039 may be planar.

[0062] The sixth segment 205 is connected to the fifth segment 203. The sixth segment 205 has a thirteenth end 205a and a fourteenth end 205b. The thirteenth end 205a may be the starting end of the sixth segment 205 and is connected to the twelfth end 203b. The fourteenth end 205b may be the ending end of the sixth segment 205. The third surface 201a of the sixth segment 205 may be provided with a second active material layer 213. The fourth surface 201b of the sixth segment 205 may not be provided with a second active material layer 213. That is, the portion of the second current collector 201 defined by the sixth segment 205 may be a current collector having only one surface coated with an active material layer. The sixth segment 205 may include a curved and / or planar current collector.

[0063] The sixth section 205 may include a sixth segment 2051, a seventh segment 2053, an eighth segment 2055, and a ninth segment 2057. Each of the sixth segment 2051, the seventh segment 2053, the eighth segment 2055, and the ninth segment 2057 may be considered as a part of the sixth section 205. The sixth segment 2051, the seventh segment 2053, the eighth segment 2055, and the ninth segment 2057 together constitute the entire sixth section 205.

[0064] The sixth section 2051 may be the starting section of the sixth section 205. The sixth section 2051 is connected to the fifth section 2039. The sixth section 2051 has a starting end 2051a and an ending end 2051b. The starting end 2051a is connected to the ending end 2039b of the fifth section 2039. The fourth surface 201b of the sixth section 2051 is provided with a second insulating colloid 215. The second insulating colloid 215 has a starting end 215a and an ending end 215b. The starting end 215a and the ending end 215b overlap with the starting end 2051a and the ending end 2051b of the sixth section 2051, respectively. The second insulating colloid 215 may include any material suitable for insulating colloid in the art. The sixth section 2051 may be curved. The seventh section 2053 is connected to the sixth section 2051. The seventh segment 2053 has a starting end 2053a and an ending end 2053b. The starting end 2053a of the seventh segment 2053 is connected to the ending end 2051b of the sixth segment 2051. The seventh segment 2053 may be planar. The eighth segment 2055 is connected to the seventh segment 2053. The eighth segment 2055 has a starting end 2055a and an ending end 2055b. The starting end 2055a of the eighth segment 2055 is connected to the ending end 2053b of the seventh segment 2053. The eighth segment 2055 may be curved. The ninth segment 2057 is connected to the eighth segment 2055. The ninth segment 2057 has a starting end 2057a and an ending end 2057b. The starting end 2057a of the ninth segment 2057 is connected to the ending end 2055b of the eighth segment 2055. The end 2057b coincides with the end 205b of the sixth section 205. The ninth section 2057 is the end section of the sixth section 205. The ninth section 2057 may be planar.

[0065] The seventh section 207 is connected to the sixth section 205. The seventh section 207 has a fifteenth end 207a and a sixteenth end 207b. The fifteenth end 207a may be the starting end of the seventh section 207 and is connected to the fourteenth end 205b. The sixteenth end 207b may be the end end of the seventh section 207, that is, the winding end end of the second pole piece 200. The third surface 201a and the fourth surface 201b of the seventh section 207 may not be provided with the second active material layer 213. That is, the portion of the second current collector 201 defined by the seventh section 207 may be a current collector that is not coated with any active material layer. The seventh section 207 may include a curved and planar current collector. The sixteenth end 207b may not overlap with the first pole tab 100, the second pole tab 200 and the fifth end 301 of the separator 300 in the thickness direction X to reduce the thickness of the wound battery cell 10I.

[0066] The seventh segment 207 may include a tenth segment 2071 and an eleventh segment 2073. The tenth segment 2071 and the eleventh segment 2073 may both be considered as a part of the seventh segment 207. The tenth segment 2071 and the eleventh segment 2073 together constitute the entire seventh segment 207.

[0067] The tenth segment 2071 may be the starting segment of the seventh segment 207. The tenth segment 2071 has a starting end 2071a and an ending end 2071b. The starting end 2071a of the tenth segment 2071 is connected to the ending end 2057b of the ninth segment 2057. The tenth segment 2071 may be curved. The third surface 201a of the tenth segment 2071 is provided with a third insulating colloid 217. The third insulating colloid 217 may include materials of insulating colloids commonly used in the art. The third insulating colloid 217 has a starting end 217a and an ending end 217b. The starting end 217a and the ending end 217b overlap with the starting end 2071a and the ending end 2071b of the tenth segment 2071, respectively. The eleventh segment 2073 is connected to the tenth segment 2071. The eleventh segment 2073 has a starting end 2073a and an ending end 2073b. The starting end 2073a of the eleventh segment 2073 is connected to the ending end 2071b of the tenth segment 2071. The eleventh segment 2073 is the ending segment of the seventh segment 207. The eleventh segment 2073 may be planar. The second pole ear 211 is provided on the third surface 201a of the eleventh segment 2073. The second pole ear 211 has a first side 211a and a second side 211b opposite to the first side 211a, and the first side 211a is provided on the third surface 201a of the eleventh segment 2073 of the second pole piece 200. The material of the second pole ear 211 may include metal. In some embodiments, the material of the second pole ear 211 may include copper. In some embodiments, the material of the second pole ear 211 may include nickel. In some embodiments, the material of the second pole ear 211 may include an alloy material of nickel, silver or copper. In some embodiments, the material of the second pole ear 211 may include any material suitable for pole ears in the art. The second pole tab 211 may be connected to the third surface 201a of the eleventh segment 2073 of the second current collector 201 by any suitable means, such as, but not limited to, resistance welding, ultrasonic welding, conductive adhesive connection, etc. The second pole tab 211 is arranged on the right side of the first pole tab 111, and does not overlap with the first pole tab 111 in the thickness direction X. The eleventh segment 2073 and the first pole tab 111 may not overlap in the thickness direction X. The second pole tab 211 may be a positive pole tab. In other embodiments of the present application, the second pole tab 211 may be a negative pole tab. The second pole tab 211 is on the right side of the first pole tab 111. In other embodiments of the present application, the second pole tab 211 may be on the left side of the first pole tab 111. The second pole tab 211 does not overlap with the first end 103a of the first pole sheet 100 and the first pole tab 111 in the thickness direction X to further reduce the thickness of the wound battery cell 10I.

[0068] The isolation film 300 may be disposed between the first pole piece 100 and the second pole piece 200. The isolation film 300 has a fifth end 301 and a sixth end 303. The fifth end 301 is the winding start end of the isolation film 300. The sixth end 303 is the winding end end of the isolation film 300. The fifth end 301 overlaps with the first pole tab 100 in the thickness direction X. In other embodiments of the present application, the fifth end 301 does not overlap with the first pole tab 100 in the thickness direction X to further reduce the thickness of the wound battery cell 10I. The sixth end 303 of the isolation film 300 does not overlap with the first pole tab 111 and the second pole tab 211 in the thickness direction X. The isolation film 300 may have a virtual first dividing line 305. The portion of the isolation film 300 formed from the first dividing line 305 to the fifth end 301 is defined as the first portion Q of the isolation film 300. The shape of the first portion Q may be a plane shape. The first portion Q overlaps with the first pole tab 100 in the thickness direction X. In other embodiments of the present application, the first portion Q may not overlap with the first pole piece 100 in the thickness direction X to further reduce the thickness of the wound battery cell 10I. The isolation film 300 located between the second section 105 and the third section 107 may have a coating to improve the safety of the wound battery cell 10I. In other embodiments of the present application, the isolation film 300 located between the second section 105 and the third section 107 may not have a coating to reduce the thickness of the wound battery cell 10I. The material of the isolation film 300 may include any material suitable for isolation films in the art. The sixth end 303 of the isolation film 300 may be flush with the end end 215b of the second insulating colloid 215 and the end end 217b of the third insulating colloid 217, or the sixth end 303 may exceed the end end 215b of the second insulating colloid 215 and the end end 217b of the third insulating colloid 217 to ensure the safety of the wound battery cell 10I.

[0069] The wound battery cell 10I may further include a first insulating colloid 400, which covers the winding end 207b of the second pole piece 200 and fixes the second pole piece 200 to the fourth surface 201b above the seventh segment 2053 of the wound battery cell 10I. The first insulating colloid 400 may include materials commonly used in the art for insulating colloids, such as, but not limited to, insulating glue, polyolefin hot melt adhesives, ethylene and its copolymer hot melt adhesives, polyurethane hot melt adhesives, or polyamide hot melt adhesives. The first insulating colloid 400 may not overlap with the first pole tab 111 and the second pole tab 211 in the thickness direction X, so as to maximize the thickness space and further improve the energy density of the wound battery cell 10I.

[0070] Since the second active material layer 213 is disposed on the third surface 201a and the fourth surface 201b of the winding start end 203a of the second current collector 201, there are no two blank current collectors that are not coated with active material layers and are opposite to each other in the wound battery cell 10I provided in the embodiment of the present application. In addition, by disposing the first pole ear 111 on the first surface 101a of the second section 105 of the first pole sheet 100, the first pole ear 111 of the wound battery cell 10I provided in the embodiment of the present application may not overlap with the first end 103a of the first pole sheet 100 in the thickness direction X, thereby reducing the thickness of the battery cell 10. The thickness of the position where the first pole ear 111 is located in the thickness direction X is composed of the thickness of the two layers of the isolation film 300 located in the central area S, the first pole ear 111 and the remaining components. The thickness of the position where the second pole ear 211 is located in the thickness direction X is composed of the thickness of the second current collector 201, the second pole ear 211 and the remaining components. Therefore, compared with the existing wound battery cells, the thickness of the wound battery cell 10I provided in the embodiment of the present application can be relatively reduced, and thus has higher energy density and space utilization.

[0071] Figure 1B FIG. 1 shows a cross-sectional schematic diagram of a wound battery cell 10II according to another embodiment of the present application. Figure 1B As shown, the wound battery cell 10II according to another embodiment of the present application is different from the wound battery cell 10I shown in FIG. 1 only in that the fifth end 301II of the isolation film 300II and the first electrode tab 111II do not overlap in the thickness direction X.

[0072] Since the fifth end 301II of the isolation film 300II does not overlap with the first end 103aII of the first pole piece 100II, the first pole tab 111II and the second pole tab 211II in the thickness direction X, the thickness of the first pole tab 111II in the thickness direction X is composed of the thickness of the first pole tab 111 and the remaining components. The thickness of the second pole tab 211II in the thickness direction X is composed of the thickness of the second current collector 201II, the second pole tab 211II and the remaining components. Therefore, the wound battery cell 10II provided in the embodiment of the present application is relatively Figure 1A The thickness of the wound battery cell 10I shown in the thickness direction X is further reduced, so that it has a higher energy density.

[0073] Figure 1C FIG. 1 shows a cross-sectional schematic diagram of a wound battery cell 10III according to another embodiment of the present application. Figure 1C As shown, according to another embodiment of the present application, the wound battery cell 10III and Figure 1BThe wound battery cell 10II shown is different only in that the shape of the first portion QIII defined by the first boundary line 305III of the separator 300III and the fifth end 301III of the separator 300III is curved.

[0074] Figure 1D FIG. 1 shows a cross-sectional schematic diagram of a wound battery cell 10IV according to another embodiment of the present application. Figure 1D As shown, according to another embodiment of the present application, the wound battery cell 10IV and Figure 1B The only difference of the wound battery cell 10II shown is that the second pole ear 211IV is located on the left side of the first pole ear 111IV. The first insulating colloid 400IV overlaps with the fifth end 301IV of the isolation film 300IV in the thickness direction X. In other embodiments of the present application, the first insulating colloid 400IV may not overlap with the fifth end 301IV of the isolation film 300IV in the thickness direction X to further reduce the thickness of the wound battery cell 10IV. The first insulating colloid 400IV does not overlap with the first end 103aIV of the first pole piece 100IV in the thickness direction X. The thickness of the position where the first pole ear 111IV is located in the thickness direction X is composed of the thickness of the first pole ear 111IV, the second current collector 201IV and the remaining components. The thickness of the position where the second pole ear 211IV is located in the thickness direction X is composed of the thickness of the second current collector 201IV, the second pole ear 211IV and the remaining components.

[0075] Figure 1E FIG. 2 shows a cross-sectional schematic diagram of a wound battery cell 10V according to another embodiment of the present application. Figure 1E As shown, according to another embodiment of the present application, the wound battery cell 10V and Figure 1B The difference of the wound battery cell 10II shown is that the first side 211aV of the second pole tab 211V is arranged on the fourth surface 201bV of the seventh segment 2053V. The thickness of the first pole tab 111V in the thickness direction X is composed of the thickness of the first pole tab 111V and the thickness of the remaining components. The thickness of the second pole tab 211IV in the thickness direction X is composed of the thickness of the second pole tab 211V and the thickness of the remaining components. Therefore, the wound battery cell 10V provided in the embodiment of the present application is different from the wound battery cell 10V provided in the embodiment of the present application. Figures 1A-1D The thickness of the wound battery cell shown in the thickness direction X can be further reduced, thereby having a higher energy density.

[0076] In other embodiments of the present application, the wound battery cell 10V may further include a fourth insulating colloid (not shown) covering the second side 211bV of the second electrode tab 211V to prevent the second electrode tab 211V from piercing the packaging bag of the wound battery cell 10V, thereby avoiding corrosion.

[0077] Figure 1FFIG. 1 shows a cross-sectional schematic diagram of a wound battery cell 10VI according to another embodiment of the present application. Figure 1F As shown, according to another embodiment of the present application, the wound battery cell 10IV and Figure 1E The wound cell 10V shown is different only in that the shape of the first portion QVI defined by the first boundary line 305VI of the isolation film 300VI and the fifth end 301VI of the isolation film 300VI is curved.

[0078] Figure 1G FIG. 1 shows a cross-sectional schematic diagram of a wound battery cell 10VII according to another embodiment of the present application. Figure 1G As shown, according to another embodiment of the present application, the wound battery cell 10VII and Figure 1E The only difference of the wound battery cell 10V shown is that the second pole tab 211VII is located on the left side of the first pole tab 111VII, and the first insulating colloid 400VII overlaps with the first pole tab 111VII in the thickness direction X. The thickness of the first pole tab 111VII in the thickness direction X is composed of the thickness of the first pole tab 111VII, the first insulating colloid 400VII and the remaining components. The thickness of the second pole tab 211VII in the thickness direction X is composed of the thickness of the second pole tab 211VII and the remaining components.

[0079] In other embodiments of the present application, the first insulating colloid 400VII may not overlap with the first pole tab 111VII in the thickness direction X. The thickness of the first pole tab 111VII in the thickness direction X is composed of the thickness of the first pole tab 111VII and the remaining components. The thickness of the second pole tab 211VII in the thickness direction X is composed of the thickness of the second pole tab 211VII and the remaining components.

[0080] Figure 1H FIG. 1 shows a cross-sectional schematic diagram of a wound battery cell 10VIII according to another embodiment of the present application. Figure 1H As shown, according to another embodiment of the present application, the wound battery cell 10VIII and Figure 1G The only difference of the wound battery cell 10VII shown is that the shape of the first part QVIII defined by the first dividing line 305VIII of the isolation film 300VIII and the fifth end 301VIII of the isolation film 300VIII is curved. A part of the first part QVIII overlaps with the second pole tab 211VIII in the thickness direction X. The thickness of the position where the first pole tab 111VIII is located in the thickness direction X is composed of the thickness of the first pole tab 111VIII, the first insulating colloid 400VIII and the remaining components. The thickness of the position where the second pole tab 211VIII is located in the thickness direction X is composed of the thickness of the second pole tab 211VIII, the two layers of isolation film 300 and the remaining components.

[0081] In other embodiments of the present application, the first insulating colloid 400VIII may not overlap with the first pole tab 111VIII in the thickness direction X, and the first portion QVIII may not overlap with the second pole tab 211VIII in the thickness direction X. The thickness of the first pole tab 111VIII in the thickness direction X is composed of the thickness of the first pole tab 111VIII and the remaining components. The thickness of the second pole tab 211VIII in the thickness direction X is composed of the thickness of the second pole tab 211VIII and the remaining components.

[0082] Fig. 1I FIG. 1 shows a cross-sectional schematic diagram of a wound battery cell 10IX according to another embodiment of the present application. Fig. 1I As shown, according to another embodiment of the present application, the wound battery cell 10IX and Figure 1E The only difference of the wound battery cell 10V shown is that the first insulating colloid 400IX covers the second side 211bIX of the second pole tab 211IX to prevent the second pole tab 211IX from piercing the packaging bag of the wound battery cell 10IX, thereby avoiding corrosion.

[0083] Figure 1J FIG. 2 shows a cross-sectional schematic diagram of a wound battery cell 10X according to another embodiment of the present application. Figure 1J As shown, according to another embodiment of the present application, a wound battery cell 10X and Figure 1E The only difference of the wound cell 10V shown is that the second pole tab 211X is located below the eleventh segment 2073X. The thickness of the first pole tab 111X in the thickness direction X is composed of the thickness of the first pole tab 111X and the remaining components. The thickness of the second pole tab 211X in the thickness direction X is composed of the thickness of the second pole tab 211X, the second current collector 201X and the remaining components.

[0084] Figure 1K FIG. 2 shows a cross-sectional schematic diagram of a wound battery cell 10XI according to another embodiment of the present application. Figure 1K As shown, according to another embodiment of the present application, the wound battery cell 10XI and Figure 1JThe difference of the wound battery cell 10X shown is that the first side 211aXI of the second pole ear 211XI is located on the fourth surface 201bXI of the first part 2035cXI of the third segment 2035XI. Neither the third surface 201aXI nor the fourth surface 201bXI of the first part 2035cXI is provided with the first or second active material layer. The wound battery cell 10XI also includes a fifth insulating colloid 500XI, which is arranged on the second side 211bXI of the second pole ear 211XI and shields the surface of the first part 2035cXI to which the first side 211aXI of the second pole ear 211XI is connected, so as to prevent the welding burrs of the second pole ear 211XI from piercing the isolation film 300 and causing the risk of short circuit. The wound battery cell 10XI may further include a sixth insulating colloid 600XII, which is opposite to the fifth insulating colloid 500XII and shields the surface of the first portion that is not connected to the first side 211aXI of the second pole tab 211XI to prevent the welding burr of the second pole tab 211XI from piercing the isolation film 300XI and causing a short circuit risk. The materials of the fifth insulating colloid 500XI and the sixth insulating colloid 600XI may include materials of insulating colloids commonly used in the art.

[0085] In other embodiments of the present application, the first side 211aXI of the second pole tab 211XI may be located on the fourth surface 201bXI of the second portion of the fifth segment 2039XI. The second portion of the fifth segment 2039XI is similar to the first portion 2035cXI, and the third surface 201aXI and the fourth surface 201bXI thereof are not provided with an active material layer, and the fifth insulating colloid 500XI is provided on the second side 211bXI of the second pole tab 211XI and shields the surface of the second portion to which the second side 211bXI of the second pole tab 211XI is connected, and the sixth insulating colloid 600XI is opposite to the fifth insulating colloid 500XI and shields the surface of the second portion that is not connected to the first side 211aXI of the second pole tab 211XI.

[0086] Figure 1L FIG. 1 shows a cross-sectional schematic diagram of a wound battery cell 10XII according to another embodiment of the present application. Figure 1L As shown, according to another embodiment of the present application, the wound battery cell 10XII and Figure 1KThe wound cell 10XI shown is different only in that the first side 211aXII of the second pole tab 211XII is located on the third surface 201aXII of the first part 2035cXII of the third segment 2035XII. The third surface 201aXII and the fourth surface 201bXII of the first part 2035cXII are not provided with an active material layer. The wound cell 10XII also includes a fifth insulating colloid 500XII, which is arranged on the second side 211bXII of the second pole tab 211XII and shields the surface of the first part 2035cXII to which the second side 211bXII of the second pole tab 211XII is connected. The wound cell 10XII may also include a sixth insulating colloid 600XII, which is opposite to the fifth insulating colloid 500XII and is arranged on the surface of the first part 2035cXII that is not connected to the first side 211aXII of the second pole tab 211XII. The shape of the first portion QXII defined by the first boundary line 305XII of the isolation film 300XII and the fifth end 301XII of the isolation film 300XII is a curved shape.

[0087] In other embodiments of the present application, the first side 211aXII of the second pole ear 211XII may be located on the third surface 201aXII of the second part of the fifth segment 2039XII. The second part of the fifth segment 2039XII is similar to the first part 2035cXII, and the third surface 201aXII and the fourth surface 201bXII thereof are not provided with an active material layer. The fifth insulating colloid 500XII is provided on the second side 211bXII of the second pole ear 211XII and shields the surface of the second part to which the second side 211bXII of the second pole ear 211XII is connected. The sixth insulating colloid 600XII is opposite to the fifth insulating colloid 500XII and shields the surface of the second part that is not connected to the first side 211aXII of the second pole ear 211XII to prevent the welding burr of the second pole ear 211XII from piercing the isolation film 300XII and causing a short circuit risk.

[0088] Figure 1M FIG. 1 shows a cross-sectional schematic diagram of a wound battery cell 10XIII according to another embodiment of the present application. Figure 1M As shown, according to another embodiment of the present application, the wound battery cell 10XIII and Figure 1LThe difference of the wound battery 10XII shown is that the wound battery 10XIII also includes a seventh insulating layer 700XIII, which is arranged at the corresponding position of the first pole piece 111XIII opposite to the fifth insulating colloid 500XIII and the sixth insulating colloid 600XIII. The fifth insulating colloid 500XIII and the sixth insulating colloid 600XIII can further prevent the short circuit risk caused by the welding burrs of the second pole ear 211XIII piercing the isolation film, so as to further improve the safety performance. The thickness of the fifth insulating colloid 500XIII, the sixth insulating colloid and the seventh insulating layer 700XIII in the thickness direction X may be less than the thickness of the pole ear. The material of the seventh insulating layer 700XIII may include the material of the insulating colloid commonly used in the art. The shape of the first part QXIII defined by the first dividing line 305XIII of the isolation film 300XIII and the fifth end 301XIII of the isolation film 300XIII is planar.

[0089] Figure 1N FIG. 1 shows a cross-sectional schematic diagram of a wound battery cell 10XIV according to another embodiment of the present application. Figure 1N As shown, according to another embodiment of the present application, the wound battery cell 10XIV and Figure 1M The wound battery cell 10XIII shown is different only in that the second pole tab 211XIV is located on the left side of the first pole tab 111XIV.

[0090] An embodiment of the present application also provides an electrochemical device, which includes a wound battery cell according to any one of the embodiments of the present application.

[0091] The technical content and technical features of this application have been disclosed as above, but those skilled in the art may still make various substitutions and modifications based on the teachings and disclosures of this application without departing from the spirit of this application. Therefore, the protection scope of this application should not be limited to the contents disclosed in the embodiments, but should include various substitutions and modifications without departing from this application, and be covered by the claims of this application.

Claims

1. A wound battery cell, characterized in that: include: A first pole piece, a second pole piece and an isolation film, wherein the isolation film is disposed between the first pole piece and the second pole piece, and the first pole piece, the second pole piece and the isolation film are wound to form the wound battery cell; The wound battery cell has a thickness direction and a central area enclosed by the first pole piece, the second pole piece and the isolation film; The first pole piece comprises: A first current collector, the first current collector comprising: a first surface and a second surface opposite to the first surface, the first surface being closer to the central area than the second surface; a first section, the first section comprising a first plane section and a first curved section connected in sequence along a winding direction, the first surface and the second surface of the first plane section are not provided with a first active material layer, the first section has a first end and a second end, the first end is located in the first plane section, the first end is a winding starting end of the first pole piece, and the second end is located in the first curved section; and a second section, wherein the second section has a third end and a fourth end, and the third end is connected to the second end; the second section is planar, and the first surface of the second section is provided with a first pole ear, and the first pole ear is connected to the first surface of the second section through a conductive adhesive; the first surface of the second section is not provided with the first active material layer, and the second surface of the second section is provided with the first active material layer, and the second surface of the second section is opposite to the second pole piece; The second pole piece comprises: a second pole tab, the second pole tab having a first side and a second side opposite to the first side, the first side being disposed on the second pole piece; Wherein, the first plane segment, the first pole tab and the second pole tab do not overlap in the thickness direction; In the thickness direction, the second section is closer to the central area than a winding start section of the second pole piece.

2. The wound battery cell according to claim 1, wherein the isolation film has a fifth end and a sixth end, the fifth end is the winding start end of the isolation film, the sixth end is the winding end end of the isolation film, and the fifth end does not overlap with the first end, the first pole tab, and the second pole tab in the thickness direction; The isolation membrane includes a starting section. Along the thickness direction, the starting section covers the first plane section. Along the winding direction, one end of the starting section is the fifth end. The line between the other end of the starting section and the junction of the first plane section and the first curved section is parallel to the thickness direction. The starting section does not overlap with the first pole ear and the second pole ear. 3 . The wound battery cell according to claim 2 , wherein the sixth end does not overlap with the first electrode tab and the second electrode tab in the thickness direction.

4. The wound battery cell according to claim 2, wherein the isolation membrane has a first dividing line, the first dividing line to the fifth end constitute a first part of the isolation membrane, the first part is curved or planar, and the first part does not overlap with the first pole ear and the second pole ear in the thickness direction. 5 . The wound battery cell according to claim 1 , wherein the wound battery cell further comprises a first insulating colloid covering the winding end of the second pole piece, and the first insulating colloid does not overlap with the first pole tab and the second pole tab in the thickness direction. 6 . The wound battery cell according to claim 1 , wherein a winding end of the second pole sheet does not overlap with the first pole tab and the second pole tab in the thickness direction. 7 . The wound battery cell according to claim 1 , wherein the first surface and the second surface of the first section are not provided with a first active material layer.

8. The wound battery cell according to claim 1, wherein the first pole piece further comprises: The third and fourth sections, among which, The third section has a seventh end and an eighth end, and the seventh end is connected to the fourth end; The fourth section has a ninth end and a tenth end, the ninth end is connected to the eighth end, and the tenth end is the winding end of the first pole piece; and The first active material layer is not disposed on the first surface of the third section, the first active material layer is disposed on the second surface of the third section, and the first active material layer is disposed on the first surface and the second surface of the fourth section. 9 . The wound battery cell according to claim 8 , wherein the separator between the second section and the third section has a coating or has no coating.

10. The wound battery cell according to claim 2, wherein the second pole piece comprises a second current collector, and the second current collector comprises: a third surface and a fourth surface opposite to the third surface, the third surface being closer to the central area than the fourth surface; The second pole piece further comprises: The fifth section, the sixth section and the seventh section, wherein: The fifth section has an eleventh end and a twelfth end, and the eleventh end is a winding starting end of the second pole piece; The sixth section has a thirteenth end and a fourteenth end, the thirteenth end is connected to the twelfth end; the seventh section has a fifteenth end and a sixteenth end, the fifteenth end is connected to the fourteenth end, and the sixteenth end is the winding end of the second pole piece; and The third surface and the fourth surface of the fifth segment are provided with a second active material layer; the third surface of the sixth segment is provided with the second active material layer; and the third surface and the fourth surface of the seventh segment are not provided with the second active material layer.

11. The wound battery cell according to claim 10, wherein: The fifth section includes a first section, a second section, a third section, a fourth section and a fifth section, wherein the first section, the third section and the fifth section are planar, the second section and the fourth section are curved, the first section is the starting section of the fifth section, the second section is connected to the first section, the third section is connected to the second section, the fourth section is connected to the third section, and the fifth section is the ending section of the fifth section; The sixth section includes a sixth section, a seventh section, an eighth section and a ninth section, wherein the sixth section and the eighth section are curved, the seventh section and the ninth section are planar, the sixth section is the starting section of the sixth section, the seventh section is connected to the sixth section, the eighth section is connected to the seventh section, the ninth section is connected to the eighth section, and the ninth section is the ending section of the sixth section; The seventh section includes a tenth section and an eleventh section, wherein the tenth section is curved, the eleventh section is planar, the tenth section is the starting section of the seventh section, and the eleventh section is the ending section of the seventh section; The fourth surface of the sixth segment is provided with a second insulating colloid, the starting end and the ending end of the second insulating colloid respectively coincide with the starting end and the ending end of the sixth segment, and the starting end of the sixth segment is connected to the fifth segment; the third surface of the tenth segment is provided with a third insulating colloid, the starting end and the ending end of the third insulating colloid respectively coincide with the starting end and the ending end of the tenth segment, and the starting end of the tenth segment is connected to the sixth segment. 12 . The wound battery cell according to claim 11 , wherein the sixth end exceeds the end ends of the second insulating colloid and the third insulating colloid, or the sixth end is flush with the end ends of the second insulating colloid and the third insulating colloid. 13 . The wound battery cell according to claim 11 , wherein the first side of the second electrode tab is disposed on the third surface of the eleventh segment. 14 . The wound battery cell according to claim 11 , wherein the first side of the second electrode tab is disposed on the fourth surface of the seventh segment. 15 . The wound battery cell according to claim 14 , wherein the wound battery cell further comprises a fourth insulating colloid covering the second side of the second electrode tab. 16 . The wound battery cell according to claim 1 , wherein the wound battery cell further comprises a first insulating colloid covering the winding end of the second pole piece, and the first insulating colloid covers the second side of the second pole lug. 17 . The wound battery cell according to claim 14 , wherein the second electrode tab is located below the eleventh segment.

18. The wound battery cell according to claim 11, wherein the third segment has a first portion, the third surface and the fourth surface of the first portion are not provided with the second active material layer, and the first side of the second pole ear is provided on one of the third surface and the fourth surface of the first portion; or, the fifth segment has a second portion, the third surface and the fourth surface of the second portion are not provided with the second active material layer, and the first side of the second pole ear is provided on one of the third surface and the fourth surface of the second portion; the wound battery cell further comprises: a fifth insulating colloid, which is disposed on the second side of the second electrode tab and shields a corresponding surface of the first portion or the second portion to which the second side of the second electrode tab is connected; and A sixth insulating colloid is opposite to the fifth insulating colloid and shields a surface of the first portion that is not connected to the first side of the second electrode tab or a surface of the second portion that is not connected to the first side of the second electrode tab. 19 . The wound battery cell according to claim 18 , further comprising a seventh insulating layer disposed at a corresponding position of the first pole piece opposite to the fifth insulating colloid and the sixth insulating colloid. 20 . The wound battery cell according to claim 1 , wherein the wound battery cell has a center line parallel to the thickness direction, and along a length direction perpendicular to the thickness direction, the first pole tab and the second pole tab are located on different sides of the center line.

21. An electrochemical device, characterized in that: A wound battery cell comprising any one of claims 1-20.

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