Pole piece assembly, electrochemical device, and electronic device

Abstract

The utility model relates to electrochemical energy storage technical field discloses a kind of pole piece assembly, electrochemical device and electronic equipment, including pole piece, pole lug, conducting sheet and electrically conductive connecting piece, pole piece includes composite current collector, composite current collector is equipped with through groove, and including first conducting layer, insulating layer and second conducting layer sequentially connected along thickness direction, through groove sequentially penetrates first conducting layer, insulating layer and second conducting layer along thickness direction;Pole lug is connected to first conducting layer, and part and through groove are opposite;Conducting sheet is connected to second conducting layer, and part and through groove are opposite;Electrically conductive connecting piece is located in through groove, and including first conducting part and second conducting part, first conducting part is connected to pole lug, and second conducting part is connected to conducting sheet and first conducting part respectively;Wherein, first conducting part and pole lug are integrally formed;And / or, second conducting part and conducting sheet are integrally formed, so as to be able to improve the through effect between first conducting layer and second conducting layer.

Description

Technical Field

[0001] This utility model relates to the field of electrochemical energy storage technology, and in particular to electrode components, electrochemical devices, and electronic equipment. Background Technology

[0002] Composite current collectors consist of a conductive layer, a polymer layer, and another conductive layer. Due to their high safety, their applications are becoming increasingly widespread. Since the conductive layers on both sides of a composite current collector are not conductive, the normal operation of the battery cannot be guaranteed. Therefore, the two conductive layers need to be welded together to make them conductive.

[0003] In the existing technology, it is difficult to guarantee the welding quality between the two conductive layers. Poor welding quality can easily affect the conductivity between the two conductive layers. Utility Model Content

[0004] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes an electrode assembly capable of improving the conductivity between the first conductive layer and the second conductive layer.

[0005] This application also proposes an electrochemical device having the above-mentioned electrode assembly, and an electronic device having the electrochemical device.

[0006] An electrode assembly according to a first aspect of this application includes an electrode, a tab, a conductive sheet, and a conductive connector. The electrode includes a composite current collector, which has a conductive groove and includes a first conductive layer, an insulating layer, and a second conductive layer connected sequentially along the thickness direction. The conductive groove passes through the first conductive layer, the insulating layer, and the second conductive layer sequentially along the thickness direction. The tab is connected to the first conductive layer and partially opposite to the conductive groove. The conductive sheet is connected to the second conductive layer and partially opposite to the conductive groove. The conductive connector is disposed in the conductive groove and includes a first conductive portion and a second conductive portion. The first conductive portion is connected to the tab, and the second conductive portion is connected to the conductive sheet and the first conductive portion, respectively. The first conductive portion and the tab are integrally formed; and / or, the second conductive portion and the conductive sheet are integrally formed.

[0007] The electrode assembly according to the embodiments of this application has at least the following beneficial effects: In the electrode assembly, electrochemical device, and electronic device provided in the embodiments of this application, by connecting the electrode tab to the first conductive layer of the composite current collector, connecting the conductive sheet to the second conductive layer of the composite current collector, and disposing of the conductive connector in the conductive groove of the composite current collector, the first conductive part of the conductive connector is connected to the electrode tab, and the second conductive part of the conductive connector is connected to the conductive sheet and the first conductive part respectively, thereby enabling the electrode tab, the first conductive layer, and the second conductive layer to conduct electricity, and the electrochemical device to charge and discharge normally; in addition, the first conductive part and the second conductive part can be directly supported between the electrode tab and the conductive sheet, which helps to improve the situation where the electrode tab or the conductive sheet is deformed at the position of the conductive groove, and the welding head and welding seat of the welding equipment can better fit the electrode tab and the conductive sheet respectively, which helps to improve the welding quality and improve the conductivity between the electrode tab, the first conductive layer, and the second conductive layer, and can reduce the situation of long charging time and high charging temperature of the electrochemical device due to poor welding quality. By making the first conductive part and the electrode tab integrally molded, and / or making the second conductive part and the conductive sheet integrally molded, the connection nodes (such as solder joints) between the first conductive part and the electrode tab and / or the connection nodes between the second conductive part and the conductive sheet can be eliminated, thereby improving the stability of conductivity and the connection strength, and further improving the long charging time and high charging temperature of the electrochemical device.

[0008] In some embodiments, the electrode further includes a first active layer and a second active layer, the first active layer being connected to a first conductive layer and the second active layer being connected to a second conductive layer; the first active layer has a first mounting groove to expose a portion of the first conductive layer to form a first blank area, and the electrode tab is located in the first mounting groove and stacked in the first blank area; the second active layer has a second mounting groove to expose a portion of the second conductive layer to form a second blank area, and the conductive connector is at least partially located in the first mounting groove and stacked in the second blank area; a conductive groove connects the first mounting groove and the second mounting groove respectively, and the first mounting groove extends to the edge penetrating the first active layer.

[0009] In some embodiments, the first conductive part and the second conductive part are integrally formed; and / or, the thickness of the conductive connector is ≤ the thickness of the composite current collector; and / or, the projection of the conductive connector on the tab along the thickness direction overlaps with the tab, and the width of the conductive connector is ≤ the width of the tab.

[0010] In some embodiments, the conductive connector and the inner wall of the conductive groove are spaced apart.

[0011] In some embodiments, the distance between the conductive connector and the inner wall of the conductive groove is ≥0.5mm and ≤2mm.

[0012] In some embodiments, the electrode tab includes a first segment and a second segment connected together. The first segment is at least partially connected to a first conductive layer and partially opposite to a conductive groove. A first conductive portion is connected to the first segment. The second segment is located outside the edge of the electrode sheet. A conductive sheet extends to the outside of the edge of the electrode sheet and is connected to the second segment.

[0013] In some embodiments, the first segment, the second segment, and the conductive sheet are integrally formed.

[0014] In some embodiments, the width of the conductive connector along the width direction of the tab is ≥1mm and ≤29mm; and / or, the length of the conductive connector along the length direction of the tab is ≥1mm and ≤9mm.

[0015] An electrochemical device according to a second aspect of this application includes the electrode assembly from any of the above embodiments.

[0016] An electronic device according to a third aspect of this application includes the electrochemical device described in the above embodiments.

[0017] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0018] The embodiments described in this application are not limited to the accompanying drawings, which are only some of the embodiments described herein. Those skilled in the art can obtain drawings of other embodiments based on the content of this application.

[0019] Figure 1 A partial structural schematic diagram of the electrode assembly provided in an embodiment of this application is shown; Figure 2 A partial cross-sectional structural schematic diagram of the composite current collector provided in an embodiment of this application is shown; Figure 3 A partial cross-sectional structural schematic diagram of the electrode assembly provided in an embodiment of this application is shown; Figure 4 A partial cross-sectional structural schematic diagram of an electrode assembly provided in another embodiment of this application is shown; Figure 5 A partial cross-sectional structural schematic diagram of an electrode assembly provided in another embodiment of this application is shown; Figure 6 A partial cross-sectional structural schematic diagram of an electrode assembly provided in another embodiment of this application is shown; Figure 7 It shows Figure 6 A schematic diagram of the structure of the middle electrode and the conductive sheet.

[0020] Figure label: Electrode assembly 100; Electrode 110; Composite current collector 111; First conductive layer 1111; Insulating layer 1113; Second conductive layer 1115; Conductive groove 1117; First active layer 113; First mounting groove 1131; Second active layer 115; Second mounting groove 1151; Tab 130; First segment 131; Second segment 133; Conductive sheet 150; Conductive connector 170; First conductive part 171; Second conductive part 173; Thickness direction X; Length direction Y; Width direction Z. Detailed Implementation

[0021] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0022] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0023] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0024] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0025] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0026] This application provides an electronic device, which includes an electrochemical device. The electronic device in this application is not particularly limited and can be any electronic device known in the prior art.

[0027] The electronic devices described in this application are not particularly limited in their application and can be used with any electronic device known in the prior art. These electronic devices include, but are not limited to, mobile phones, smartphones, laptops, tablets, wearable devices, smartwatches, smart bracelets, smart glasses, power banks, televisions, game consoles, game controllers, digital cameras, smart speakers, headphones, keyboards, mice, monitors, drones, audio equipment, home appliances, toys, power tools, automobiles, motorcycles, electric bicycles, bicycles, robots, robotic dogs, industrial robots, and android robots.

[0028] Please see Figure 1 In some embodiments, the electrochemical device includes any apparatus in which an electrochemical reaction occurs to convert chemical energy into electrical energy and vice versa, with specific, non-limiting examples including all types of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In particular, the electrochemical device is a lithium secondary battery, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, or lithium-ion polymer secondary batteries.

[0029] Please see Figure 1 In some embodiments, the electrochemical device includes a housing and a battery cell located within the housing. The battery cell includes a separator and two electrode assemblies 100 with opposite polarities. The separator is located between the two electrode assemblies 100 to isolate them. One of the two electrode assemblies 100 is a positive electrode assembly, and the other is a negative electrode assembly.

[0030] The battery cell can be a wound cell or a laminated cell. The specific structure can be referred to the existing technology, and will not be described in detail here.

[0031] Please see Figures 1 to 3 In some embodiments, the electrode assembly 100 includes an electrode 110, a tab 130, a conductive sheet 150, and a conductive connector 170.

[0032] The electrode 110 can be either a positive electrode or a negative electrode. The electrode 110 includes a composite current collector 111, which includes a first conductive layer 1111, an insulating layer 1113, and a second conductive layer 1115 connected sequentially along the thickness direction. The first conductive layer 1111 and the second conductive layer 1115 can be metal layers, and the specific metal material can be flexibly selected according to the polarity of the electrode assembly 100.

[0033] As an example, when the electrode assembly 100 is positive, the electrode 110 is a positive electrode, and the tab 130, the first conductive layer 1111, and the second conductive layer 1115 can be made of aluminum. When the electrode assembly 100 is negative, the electrode 110 is a negative electrode, and the tab 130, the first conductive layer 1111, and the second conductive layer 1115 can be made of copper. The insulating layer 1113 can be made of PET, PP, PI, or other materials.

[0034] The composite current collector 111 is provided with a through groove 1117, which passes through the first conductive layer 1111, the insulating layer 1113 and the second conductive layer 1115 in sequence along the thickness direction.

[0035] A tab 130 is connected to the first conductive layer 1111, and a portion of the tab 130 is opposite to the conductive groove 1117. The tab 130 can cover the opening formed by the conductive groove 1117 in the first conductive layer 1111. A conductive sheet 150 is connected to the second conductive layer 1115, and a portion of the conductive sheet 150 is opposite to the conductive groove 1117. The conductive sheet 150 and the tab 130 can be spaced apart and opposite to each other along the thickness direction, and the conductive sheet 150 can cover the opening formed by the conductive groove 1117 in the second conductive layer 1115.

[0036] A conductive connector 170 is disposed within a conductive groove 1117 and includes a first conductive portion 171 and a second conductive portion 173. The first conductive portion 171 is connected to the tab 130, and the second conductive portion 173 is connected to the conductive sheet 150 and the first conductive portion 171, thereby enabling conductivity between the tab 130 and the conductive sheet 150. The tab 130 is connected to the first conductive layer 1111, and the conductive sheet 150 is connected to the second conductive layer 1115, thus enabling conductivity between the tab 130, the first conductive layer 1111, and the second conductive layer 1115, allowing the electrochemical device to charge and discharge normally. Furthermore, the first conductive portion 171 and the second conductive portion 173 can be directly supported by the tab 130 and the first conductive layer 150. Between the conductive sheets 150, to fill the gap between the tabs 130 and the conductive sheets 150, under the support of the first conductive part 171 and the second conductive part 173, it helps to improve the situation where the tabs 130 or the conductive sheets 150 are deformed at the position of the conductive groove 1117. The welding head and welding seat of the welding equipment (such as ultrasonic welding equipment) can better fit the tabs 130 and the conductive sheets 150 respectively, reducing the situation of incomplete welding, helping to improve the welding quality, and improving the conductivity between the tabs 130, the first conductive layer 1111 and the second conductive layer 1115. It can reduce the situation of long charging time and high charging temperature of electrochemical device due to poor welding quality.

[0037] The guide groove 1117 can be located away from the edge of the composite current collector 111 (e.g.) Figure 3 and Figure 4As shown), the through groove 1117 can also extend through the edge of the composite current collector 111, that is, the through groove 1117 can have a slot located at the edge of the composite current collector 111 (e.g. Figure 5 (As shown).

[0038] The first conductive part 171 and the electrode tab 130 are integrally formed (e.g. Figure 5 As shown, this eliminates the connection nodes (such as solder joints) between the first conductive part 171 and the tab 130, avoiding situations such as conduction failure and high contact resistance between the first conductive part 171 and the tab 130 due to welding quality problems, thus improving the stability of conductivity and further improving the long charging time and high charging temperature of the electrochemical device. In addition, it also helps to improve the connection strength between the first conductive part 171 and the tab 130.

[0039] As an example, the first conductive part 171 and the tab 130 can be formed into an integral structure from the same foil through processes such as cutting and stamping.

[0040] And / or, the second conductive part 173 and the conductive sheet 150 are integrally formed (e.g. Figure 5 As shown, this eliminates the connection nodes (such as solder joints) between the second conductive part 173 and the conductive sheet 150, avoiding situations such as conduction failure and high contact resistance between the second conductive part 173 and the conductive sheet 150 due to welding quality problems, thus improving the stability of conductivity and further improving the long charging time and high charging temperature of the electrochemical device. In addition, it also helps to improve the connection strength between the second conductive part 173 and the conductive sheet 150.

[0041] As an example, the second conductive part 173 and the conductive sheet 150 can be formed into an integral structure from the same foil through processes such as cutting and stamping.

[0042] In addition, in areas other than the conductive groove 1117, the tab 130, the first conductive layer 1111, and the second conductive layer 1115 can also be welded using existing technology methods (i.e., piercing the composite current collector 111 to weld the tab 130, the first conductive layer 1111, and the second conductive layer 1115), which helps to increase the conductive area.

[0043] In some embodiments, the electrode 110 may further include a first active layer 113 and a second active layer 115.

[0044] The first active layer 113 is connected to the first conductive layer 1111, and the second active layer 115 is connected to the second conductive layer 1115.

[0045] The first active layer 113 may be provided with a first mounting groove 1131 so that the first conductive layer 1111 is partially exposed to form a first blank area, and the tab 130 may be partially disposed in the first mounting groove 1131 and stacked in the first blank area.

[0046] The second active layer 115 may have a second mounting groove 1151 to expose part of the second conductive layer 1115, forming a second blank area. The conductive sheet 150 may be at least partially disposed in the second mounting groove 1151 and stacked in the second blank area. The first blank area and the second blank area may be spaced apart from each other along the thickness direction.

[0047] The through groove 1117 can be located between the first mounting groove 1131 and the second mounting groove 1151, and connect the first mounting groove 1131 and the second mounting groove 1151.

[0048] The first mounting groove 1131 extends through the edge of the first active layer 113, so that the tab 130 extends outward from the edge of the composite current collector 111 (for ease of description, this edge is defined as the first edge), avoiding the superposition of the thicknesses of the first active layer 113 and the tab 130 from affecting the thickness of the electrode assembly 100. The second mounting groove 1151 may extend through the edge of the second active layer 115, or it may not extend through it, depending on the size of the conductive sheet 150.

[0049] Understandably, when the electrode 110 is a positive electrode, both the first active layer 113 and the second active layer 115 are positive active layers; when the electrode 110 is a negative electrode, both the first active layer 113 and the second active layer 115 are negative active layers.

[0050] It should be noted that the size and number of conductive connectors 170 can be set as needed to flexibly control the conductive area. When there are multiple conductive connectors 170, the number of conductive grooves 1117 is equal to the number of conductive connectors 170 and corresponds one-to-one, wherein multiple means two or more. For ease of description, this application embodiment will use one conductive connector 170 and one second conductive groove 1117 as an example for explanation.

[0051] Table 1

[0052] As shown in Table 1, Table 1 displays four sets of experimental data for welding the tab 130, the first conductive layer 1111, and the second conductive layer 1115. Serial number 1 indicates experimental data for direct welding of the tab 130, the first conductive layer 1111, and the second conductive layer 1115 without the conductive connector 170. Serial numbers 2, 3, and 4 indicate three sets of experimental data for welding the tab 130, the first conductive layer 1111, and the second conductive layer 1115 using the conductive connector 170. Specifically, serial number 2 indicates that the opening of the conductive groove 1117 is located at the first edge; serial number 3 indicates that the conductive groove 1117 is located at the tail end of the first mounting groove 1131 and the second mounting groove 1151 away from the first edge; and serial number 4 indicates that the conductive groove 1117 is located between the tail end and the first edge. It can be clearly seen from the table that the tensile force at the welding positions in serial numbers 2, 3, and 4 is significantly greater than that at the welding position in serial number 1. The welding method between the tab 130, the first conductive layer 1111, and the second conductive layer 1115 in serial numbers 2, 3, and 4 through the conductive connector 170 can effectively improve the welding strength between the three.

[0053] Furthermore, the percentage of residual solder in items 2, 3, and 4 is significantly higher than that in item 1, further indicating that the welding method using conductive connectors 170 between the tab 130, the first conductive layer 1111, and the second conductive layer 1115 in items 2, 3, and 4 can effectively improve the welding strength between the three components. Moreover, the resistance values ​​of the A / B surfaces (i.e., the resistance between the current in the first conductive layer 1111 and the second conductive layer 1115) in items 2, 3, and 4 are significantly lower than those in item 1. Therefore, the welding method using conductive connectors 170 between the tab 130, the first conductive layer 1111, and the second conductive layer 1115 in items 2, 3, and 4 can effectively improve the long charging time and high charging temperature of the electrochemical device.

[0054] Please see Figure 1 , Figure 2 and Figure 4 In some embodiments, the first conductive portion 171 and the second conductive portion 173 can be integrally formed (e.g., Figure 4 As shown, this eliminates the connection nodes (such as solder joints) between the first conductive part 171 and the second conductive part 173, avoiding situations such as conduction failure and high contact resistance between the first conductive part 171 and the second conductive part 173 due to welding quality problems, thus improving the stability of conduction. In addition, it also helps to improve the connection strength between the first conductive part 171 and the second conductive part 173.

[0055] It should be noted that when the first conductive part 171 and the tab 130 are integrally formed, the second conductive part 173 and the conductive sheet 150 are integrally formed, or the first conductive part 171 and the second conductive part 173 are integrally formed, that is, when the tab 130, the conductive sheet 150 and the conductive connector 170 are integrally formed, the first conductive part 171 and the second conductive part 173 can enter the conductive groove 1117 through the groove opening on the first edge. The tab 130 and the first conductive layer 1111 can be welded or bonded with conductive adhesive, and the conductive connector 170 and the second conductive layer 1115 can be welded or bonded with conductive adhesive. Alternatively, the tab 130, the composite current collector 111 and the second conductive layer 1115 can be welded and fixed by piercing welding, thereby achieving fixation and conduction between the tab 130, the first conductive layer 1111 and the second conductive layer 1115.

[0056] In some embodiments, the thickness of the conductive connector 170 is less than or equal to the thickness of the composite current collector 111. This helps to avoid the situation where the overall thickness of the electrode assembly 100 increases due to the thickness of the conductive connector 170 exceeding the thickness of the composite current collector 111, thereby reducing the impact on the energy density of the electrochemical device. In addition, it can also improve the situation where the thickness of the electrode assembly 100 is different at the position of the conductive groove 1117 and other positions.

[0057] Understandably, when the thickness of the conductive connector 170 is equal to the thickness of the composite current collector 111, it helps the tab 130 to better fit the first conductive layer 1111, the conductive connector 170 to better fit the second conductive layer 1115, and the thickness of the electrode assembly 100 in the conductive groove 1117 region to be more consistent with the thickness of other regions.

[0058] As an example, the first conductive part 171 and the second conductive part 173 can be distributed sequentially along the thickness direction of the composite current collector 111, and the sum of the thicknesses of the first conductive part 171 and the second conductive part 173 is the thickness of the conductive connector 170.

[0059] In some embodiments, the projection of the conductive connector 170 along the thickness direction onto the tab 130 overlaps with the tab 130, and the width of the conductive connector 170 is less than or equal to the width of the tab 130. This allows the width of the conductive connector 170 to be controlled, which helps to avoid the need for a larger conductive groove 1117 due to the excessive width of the conductive connector 170, which would require the removal of more active material and reduce the impact on the energy density of the electrochemical device.

[0060] It should be noted that the widths of the first conductive part 171 and the second conductive part 173 are equal, and the first conductive part 171 and the second conductive part 173 overlap along the thickness direction. The width of the first conductive part 171 is the width of the conductive connector 170, and the width of the second conductive part 173 can also be the width of the conductive connector 170.

[0061] When the width of the conductive connector 170 is equal to the width of the tab 130, it helps to increase the conductive area and reduces the manufacturing difficulty of integrally molding the first conductive part 171 and the tab 130.

[0062] In some embodiments, the width of the conductive connector 170 along the width direction of the tab 130 is ≥1mm and ≤29mm. This helps to avoid the situation where the conductive area is too small due to the small width of the conductive connector 170, which would lead to a long charging time and a rise in charging temperature of the electrochemical device. It also helps to avoid the situation where the space occupied by the conductive connector 170 is too large due to the large width, which would affect the energy density of the electrochemical device.

[0063] The width of the conductive connector 170 along the width direction of the tab 130 can be 1 mm, 5 mm, 10.5 mm, 21 mm, 29 mm or other values ​​in the range [1 mm, 29 mm].

[0064] In some embodiments, the length of the conductive connector 170 along the length direction of the tab 130 is ≥1mm and ≤9mm. This helps to avoid the situation where the conductive area is too small due to the length of the conductive connector 170 being too small, which would lead to a long charging time and a rise in charging temperature of the electrochemical device. It also helps to avoid the situation where the length of the conductive connector 170 is too large, which would occupy a large space and affect the energy density of the electrochemical device.

[0065] The length of the conductive connector 170 along the length direction of the tab 130 can be 1 mm, 3 mm, 5.5 mm, 7 mm, 9 mm, or within any two of the above values.

[0066] It should be noted that the lengths of the first conductive part 171 and the second conductive part 173 are equal, and the first conductive part 171 and the second conductive part 173 overlap along the thickness direction. The length of the first conductive part 171 is the length of the conductive connector 170, and the length of the second conductive part 173 can also be the length of the conductive connector 170.

[0067] In some embodiments, the inner walls of the conductive connector 170 and the conductive groove 1117 are spaced apart, such that the size of the conductive groove 1117 is larger than the size of the conductive connector 170. This makes it easier for the first conductive part 171 and the second conductive part 173 to be inserted into the conductive groove 1117, reducing the possibility that the first conductive part 171 and the second conductive part 173 cannot be inserted into the conductive groove 1117 due to manufacturing errors, thus improving the fault tolerance rate. In addition, the gap between the conductive connector 170 and the inner wall of the conductive groove 1117 can also provide deformation space for the conductive connector 170 to expand due to heat, which helps to avoid the conductive connector 170 squeezing the inner wall of the conductive groove 1117 and causing the composite current collector 111 to deform.

[0068] In some embodiments, the distance between the conductive connector 170 and the inner wall of the conductive groove 1117 is ≥0.5mm and ≤2mm, thereby controlling the distance between the conductive connector 170 and the inner wall of the conductive groove 1117. This helps to avoid limiting the expansion of the conductive connector 170 due to too small a distance, and also helps to avoid wasting space due to too large a distance, which would affect the energy density of the electrochemical device.

[0069] The distance between the conductive connector 170 and the inner wall of the conductive groove 1117 can be 0.5mm, 0.8mm, 1mm, 1.5mm, 2mm or within any two of the above values.

[0070] The dimensions of the conductive groove 1117 in the width and length directions of the tab 130 can be flexibly set according to the width and length of the conductive connector 170 and the distance between the conductive connector 170 and the inner wall of the conductive groove 1117, which will not be described in detail here.

[0071] In some embodiments, the thickness of the conductive sheet 150 is less than or equal to the thickness of the tab 130, thereby reducing the influence of the conductive sheet 150 on the thickness of the electrode assembly 100.

[0072] Please see Figure 1 , Figure 6 and Figure 7 In some embodiments, the tab 130 may include a first segment 131 and a second segment 133 connected together.

[0073] The first segment 131 is at least partially connected to the first conductive layer 1111 and partially opposite to the conductive groove 1117, that is, the first segment 131 can cover the opening formed by the conductive groove 1117 on the first conductive layer 1111.

[0074] The first conductive part 171 is connected to the first segment 131, and the second segment 133 is located on the outer side of the edge of the electrode 110 and is used for external circuit connection.

[0075] The conductive sheet 150 extends outward from the edge of the electrode 110 and connects to the second segment 133, so that the conductive sheet 150 can be directly connected to the tab 130. The conductive sheet 150 can also be connected to the tab 130 through the conductive connector 170 to form two conductive channels, which increases the conductive area of ​​the first conductive layer 1111 and the second conductive layer 1115, and further improves the long charging time and high charging temperature of the electrochemical device. In addition, if one of the two conductive channels fails, the other conductive channel can still transmit the circuit, improving the reliability of the electrochemical device. Furthermore, since the tab 130 and the conductive sheet 150 are fixedly connected, it also helps to avoid misalignment of the tab 130 and the conductive sheet 150 during the welding of the conductive connector 170.

[0076] Understandably, the second mounting groove 1151 may extend through the edge of the second active layer 115 so that the conductive sheet 150 extends outward to the edge of the electrode 110 to connect to the second segment 133, which helps to avoid the superposition of the thicknesses of the second active layer 115 and the conductive sheet 150 affecting the thickness of the electrode assembly 100.

[0077] In some embodiments, the first segment 131, the second segment 133, and the conductive sheet 150 can be integrally formed, thereby avoiding connection nodes (such as solder joints) between the first segment 131 and the second segment 133, and between the second segment 133 and the conductive sheet 150. This helps to improve the connection strength between the tab 130 and the conductive sheet 150 and reduce the contact resistance. Furthermore, there is no need to separately connect the conductive sheet 150 and the second segment 133 (such as welding the conductive sheet 150 and the second segment 133), which reduces the assembly difficulty.

[0078] In the electrode assembly 100, electrochemical device, and electronic device provided in this application embodiment, by connecting the tab 130 to the first conductive layer 1111 of the composite current collector 111, connecting the conductive sheet 150 to the second conductive layer 1115 of the composite current collector 111, and disposing of the conductive connector 170 in the conductive groove 1117 of the composite current collector 111, the first conductive portion 171 of the conductive connector 170 is connected to the tab 130, and the second conductive portion 173 of the conductive connector 170 is respectively connected to the conductive sheet 150 and the first conductive portion 171, the tab 130, the first conductive layer 1111, and the second conductive layer 1115 can be made conductive. 115. The electrochemical device can charge and discharge normally. In addition, the first conductive part 171 and the second conductive part 173 can be directly supported between the tab 130 and the conductive sheet 150, which helps to improve the situation where the tab 130 or the conductive sheet 150 is deformed at the position of the conductive groove 1117. The welding head and welding seat of the welding equipment can better fit the tab 130 and the conductive sheet 150 respectively, which helps to improve the welding quality and improve the conductivity between the tab 130, the first conductive layer 1111 and the second conductive layer 1115. This can reduce the situation of long charging time and high charging temperature of the electrochemical device due to poor welding quality. By making the first conductive part 171 and the tab 130 integrally formed, and / or making the second conductive part 173 and the conductive sheet 150 integrally formed, the connection nodes (such as solder joints) between the first conductive part 171 and the tab 130 and / or the connection nodes between the second conductive part 173 and the conductive sheet 150 can be eliminated, thereby improving the stability of conductivity and connection strength, and further improving the long charging time and high charging temperature of the electrochemical device.

[0079] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. An electrode assembly, characterized in that, include: An electrode includes a composite current collector, the composite current collector having a conductive groove, and including a first conductive layer, an insulating layer and a second conductive layer connected sequentially along the thickness direction, the conductive groove passing through the first conductive layer, the insulating layer and the second conductive layer sequentially along the thickness direction; The electrode tab is connected to the first conductive layer and is partially opposite to the conductive groove; A conductive sheet is connected to the second conductive layer and is partially opposite to the conductive groove; A conductive connector is disposed in the conductive groove and includes a first conductive part and a second conductive part. The first conductive part is connected to the electrode tab, and the second conductive part is connected to the conductive sheet and the first conductive part, respectively. Wherein, the first conductive part and the tab are integrally formed; and / or, the second conductive part and the conductive sheet are integrally formed.

2. The electrode assembly according to claim 1, characterized in that, The electrode further includes a first active layer and a second active layer, wherein the first active layer is connected to the first conductive layer and the second active layer is connected to the second conductive layer; The first active layer has a first mounting groove to expose a portion of the first conductive layer to form a first blank area, and the tab portion is located in the first mounting groove and stacked in the first blank area; the second active layer has a second mounting groove to expose a portion of the second conductive layer to form a second blank area, and the conductive connector is at least partially located in the first mounting groove and stacked in the second blank area. The conductive grooves connect the first mounting groove and the second mounting groove respectively, and the first mounting groove extends to the edge that penetrates the first active layer.

3. The electrode assembly according to claim 1, characterized in that, The first conductive part and the second conductive part are integrally formed; And / or, the thickness of the conductive connector is less than or equal to the thickness of the composite current collector; And / or, the projection of the conductive connector onto the tab along the thickness direction overlaps with the tab, and the width of the conductive connector is less than or equal to the width of the tab.

4. The electrode assembly according to claim 1, characterized in that, The conductive connector and the inner wall of the conductive groove are spaced apart.

5. The electrode assembly according to claim 4, characterized in that, The distance between the conductive connector and the inner wall of the conductive groove is ≥0.5mm and ≤2mm.

6. The electrode assembly according to claim 1, characterized in that, The electrode includes a first segment and a second segment connected to each other. The first segment is at least partially connected to the first conductive layer and partially opposite to the conductive groove. The first conductive part is connected to the first segment. The second segment is located on the outer side of the edge of the electrode sheet; The conductive sheet extends outward from the edge of the electrode and connects to the second segment.

7. The electrode assembly according to claim 6, characterized in that, The first segment, the second segment, and the conductive sheet are integrally formed.

8. The electrode assembly according to claim 1, characterized in that, The width of the conductive connector along the width direction of the electrode tab is ≥1mm and ≤29mm; And / or, the length of the conductive connector along the length direction of the tab is ≥1mm and ≤9mm.

9. An electrochemical device, characterized in that, Includes the electrode assembly according to any one of claims 1 to 8.

10. An electronic device, characterized in that, Includes the electrochemical device according to claim 9.

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