Current collector, battery and electronic device

Abstract

The present application provides a current collector, a battery, and an electronic device. The current collector includes a first current collecting layer and a composite conductive layer. The composite conductive layer and the first current collecting layer are stacked, and the elongation of the composite conductive layer is greater than that of the first current collecting layer. The battery includes the current collector, a first active material provided on the side of the first current collecting layer of the current collector facing away from the composite conductive layer, and a second active material provided on the side of the composite conductive layer of the current collector facing away from the first current collecting layer. The electronic device includes the battery and a charging circuit, and the charging circuit is electrically connected to the battery. The current collector, battery, and electronic device provided in the present application have high energy density and high safety performance.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a current collector, a battery, and an electronic device. Background Art

[0002] Lithium-ion batteries are widely used in electronic devices due to their high energy density and minimal environmental impact. However, when mechanically damaged, such as by squeezing, puncture, or impact, lithium-ion batteries can short-circuit internally. This causes a sharp rise in temperature at the short-circuit point, leading to battery combustion or even explosion. Therefore, improving the safety of lithium-ion batteries while maintaining their high energy density has become a pressing technical challenge. Summary of the Invention

[0003] The present application provides a current collector, a battery, and an electronic device with higher energy density and higher safety performance.

[0004] In one aspect, the present application provides a current collector, comprising:

[0005] the first collector layer; and

[0006] A composite conductive layer is stacked with the first current collecting layer, and the elongation of the composite conductive layer is greater than the elongation of the first current collecting layer.

[0007] On the other hand, the present application also provides a battery, including a pole piece, which includes the current collector, a first active material arranged on the side of the first current collecting layer away from the composite conductive layer, and a second active material arranged on the side of the composite conductive layer away from the first current collecting layer.

[0008] On the other hand, the present application also provides an electronic device, comprising the battery and a charging circuit, wherein the charging circuit is electrically connected to the electrode.

[0009] By providing a composite conductive layer on the first current collector layer, and ensuring that the composite conductive layer has a greater elongation than the first current collector layer, the composite conductive layer, due to its higher elongation, can undergo significant tensile deformation when the current collector is mechanically damaged, thereby reducing the possibility of the current collector being punctured. Furthermore, the composite conductive layer is conductive, reducing the internal resistance of the current collector, thereby ensuring the energy density of the current collector and improving the current collecting performance of the current collector. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments.

[0011] Figure 1 This is a schematic diagram of the external structure of an electronic device provided in an embodiment of the present application;

[0012] Figure 2 is Figure 1 exploded view of the electronic device shown;

[0013] Figure 3 is Figure 2 structural schematic diagram of a charging circuit provided in the electronic device shown;

[0014] Figure 4 is Figure 3 schematic diagram of the charging circuit shown connecting the charging interface and the battery;

[0015] Figure 5 is Figure 2 structural schematic diagram of another charging circuit provided in the electronic device shown;

[0016] Figure 6 is Figure 5 internal structural schematic diagram of the battery in the electronic device shown;

[0017] Figure 7 is Figure 6 structural schematic diagram of the positive electrode plate, separator, and negative electrode plate in the battery shown;

[0018] Figure 8 is Figure 7 structural schematic diagram of the positive electrode plate of the battery shown having a composite conductive layer;

[0019] Figure 9 is Figure 5 structural schematic diagram of a heating element provided in the electronic device shown;

[0020] Figure 10 is Figure 7 structural schematic diagram of the negative electrode plate of the battery shown having a composite conductive layer;

[0021] Figure 11 is Figure 7 structural schematic diagram of both the positive electrode plate and the negative electrode plate of the battery shown having a composite conductive layer;

[0022] Figure 12 is Figure 9 structural schematic diagram of a heating circuit provided in the electronic device shown;

[0023] Figure 13 is Figure 12 schematic diagram of the heating circuit shown connecting the heating element and the battery;

[0024] Figure 14 is Figure 12 schematic diagram of the heating circuit shown connecting the heating element and an external power supply;

[0025] Figure 15 isFigure 11 A schematic structural diagram of the positive electrode plate in the battery shown;

[0026] Figure 16 is Figure 15 A schematic structural diagram of the positive electrode plate shown with a tab;

[0027] Figure 17 is Figure 15 A schematic structural diagram of the composite conductive layer of the positive electrode plate shown with a conductive part and an adhesive part;

[0028] Figure 18 is Figure 17 A schematic structural diagram of a setting method of the conductive part and the adhesive part shown;

[0029] Figure 19 is Figure 17 A schematic structural diagram of another setting method of the conductive part and the adhesive part shown;

[0030] Figure 20 is Figure 17 A schematic structural diagram of yet another setting method of the conductive part and the adhesive part shown;

[0031] Figure 21 is Figure 20 A side view of yet another setting method of the conductive part and the adhesive part shown;

[0032] Figure 22 is Figure 17 A schematic structural diagram of still another setting method of the conductive part and the adhesive part shown;

[0033] Figure 23 is Figure 22 A side view of still another setting method of the conductive part and the adhesive part shown;

[0034] Figure 24 is Figure 15 A schematic structural diagram of the composite conductive layer of the positive current collector shown with an adhesive layer and conductive particles;

[0035] Figure 25 is Figure 24 A schematic structural diagram of the conductive particles distributed on the outer surface of the adhesive layer shown;

[0036] Figure 26 is Figure 24 A schematic structural diagram of the composite conductive layer of the positive current collector shown further with magnetic particles;

[0037] Figure 27 is Figure 2,6 A schematic structural diagram of the magnetic particles distributed on the outer surface of the adhesive layer shown. Detailed implementation manners

[0038] Lithium-ion batteries are often set as rechargeable batteries in electronic devices such as mobile phones. A lithium-ion battery consists of a positive electrode, a negative electrode, a separator, and an electrolyte. The positive and negative electrodes are immersed in the electrolyte, and lithium ions move between the positive and negative electrodes with the electrolyte as the medium to achieve the charge and discharge of the battery. Among them, the separator is often set as a polymer film, and the film has a microporous structure that allows lithium ions to pass freely while electrons cannot pass through. The separator is used to isolate the positive and negative electrodes to prevent the positive and negative electrodes from contacting and causing short circuits and explosions in the battery. If the separator is damaged when it is mechanically damaged, the positive and negative electrodes will contact at the damaged position of the separator, forming a short-circuit point, and the temperature at the short-circuit point will rise sharply, easily causing safety problems. Therefore, to ensure the safety of lithium-ion batteries during actual use, in addition to testing them under necessary mechanical abuse during the production process, it is also necessary to further improve the internal structure of lithium-ion batteries to reduce the possibility of short circuits when the batteries are mechanically damaged, thereby improving the safety of the batteries. For this purpose, through the structural design of the current collector in the lithium-ion battery, this application provides a current collector, a battery, and an electronic device with higher energy density and higher safety performance.

[0039] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application.

[0040] As Figure 1 shown, Figure 1 is a schematic external structure diagram of an electronic device 100 provided by an embodiment of this application. The electronic device 100 can be a device equipped with a rechargeable battery such as a mobile phone, a mobile power supply, a tablet computer, a laptop computer, an e-book, an electronic watch, a bracelet, smart glasses, a floor-sweeping robot, wireless earphones, a Bluetooth speaker, an electric toothbrush, a rechargeable mouse, etc. The embodiment of this application will be described by taking a mobile phone as an example.

[0041] As Figure 2 shown, Figure 2 is Figure 1 a schematic exploded view of the electronic device 100 shown. The electronic device 100 includes a display screen 2, a middle frame 3, a housing 4, and a battery 1. The display screen 2, the middle frame 3, and the housing 4 are fixedly connected in sequence to form a receiving space 5. The battery 1 is disposed in the receiving space 5.

[0042] The battery 1 is used to supply power to the display screen 2 and components such as the main board disposed on the middle frame 3. Among them, the battery 1 includes but is not limited to lithium-ion batteries, lithium-metal batteries, lithium-polymer batteries, lead-acid batteries, nickel-metal hydride batteries, nickel-manganese-cobalt batteries, lithium-sulfur batteries, lithium-air batteries, nickel-hydrogen batteries, lithium-ion batteries, iron batteries, and nano-batteries. The embodiment of this application will be described by taking a lithium-ion battery as an example.

[0043] Furthermore, as Figure 3As shown, the electronic device 100 further includes a charging circuit 6. The charging circuit 6 is disposed in the accommodation space 5.

[0044] In one embodiment, please refer to Figure 3 and Figure 4 , the middle frame 3 of the electronic device 100 is provided with a charging interface 30. The types of the charging interface 30 include but are not limited to the Micro USB interface, the USB Type C interface of Android and Windows phone system mobile phones, and the Lightning interface of IOS system mobile phones. The charging interface 30 is used to connect to an external power source. Optionally, the charging interface 30 can be connected to the external power source through a charging cable. The charging circuit 6 is connected to the battery 1 and the charging interface 30. Specifically, the charging interface 30 includes a first charging terminal 301 and a second charging terminal 302. The first charging terminal 301 is used to connect to the positive electrode end of the external power source, and the second charging terminal 302 is used to connect to the negative electrode end of the external power source. The charging circuit 6 is connected to the positive electrode 101 of the battery 1 and the first charging terminal 301, and is connected to the negative electrode 110 of the battery 1 and the second charging terminal 302. It can be understood that a charging loop is formed among the charging interface 30, the charging circuit 6 and the battery 1, and the battery 1 is charged when the charging interface 30 is connected to the external power source. Among them, the charging circuit 6 can be a flexible circuit board, an integrated circuit, a conductive wire, etc. The charging circuit 6 can be disposed on the main board of the electronic device 100.

[0045] Of course, in other embodiments, as Figure 5 shown, a receiving coil 40 can be provided on the housing 4 of the electronic device 100. The charging circuit 6 is connected to the battery 1 and the receiving coil 40. In this embodiment, the receiving coil 40 and the transmitting coil of the external power source transmit wireless electromagnetic waves to generate a current in the charging circuit 6 to charge the battery 1. In other words, a charging loop is formed among the receiving coil 40, the charging circuit 6 and the battery 1, and the battery 1 is charged when the receiving coil 40 receives the radio signal of the external transmitting coil.

[0046] As Figure 6 shown, Figure 6 is Figure 5 a schematic internal structure diagram of the battery 1 in the electronic device 100 shown. The battery 1 includes a positive electrode plate 10, a negative electrode plate 11, a separator 12 and an electrolyte 13.

[0047] Among them, the separator 12 can be a single-layer polypropylene film (PP), a single-layer polyethylene film (PE), PP-coated ceramic, PE-coated ceramic, double-layer PP, double-layer PE, single-layer PP and single-layer PP, three-layer PP, three-layer PE, single-layer PP and multi-layer PE, single-layer PE and multi-layer PP, a coated polyester film (PET, Polyethylene Terephthalate), a cellulose film, a polyimide film (PI), a polyamide film (PA), a spandex film, an aramid film, etc.

[0048] Among them, the electrolyte 13 can include a lithium salt and an organic solvent. The lithium salt can be lithium perchlorate, lithium hexafluorophosphate, lithium tetrafluoroborate, etc. The organic solvent can be ethylene carbonate, diethyl phosphate, dimethyl carbonate, ethyl methyl carbonate, etc.

[0049] Among them, please refer to Figure 6 and Figure 7 , the positive electrode plate 10 and the negative electrode plate 11 are arranged at intervals. The positive electrode plate 10 includes a positive current collector 102 and a positive active material 103 provided on the outer surface of the positive current collector 102. The negative electrode plate 11 includes a negative current collector 112 and a negative active material 113 provided on the outer surface of the negative current collector 112. The separator 12 is arranged at intervals between the positive electrode plate 10 and the negative electrode plate 11. The electrolyte 13 flows between the positive electrode plate 10 and the negative electrode plate 11.

[0050] In one embodiment, as Figure 8 shown, the positive current collector 102 includes a first current collecting layer 104 and a composite conductive layer 105. The first current collecting layer 104 and the composite conductive layer 105 are stacked. The composite conductive layer 105 is provided on the side of the first current collecting layer 104 facing the separator 12. The positive active material 103 is provided on the side of the first current collecting layer 104 facing away from the composite conductive layer 105. The first current collecting layer 104 can be an aluminum foil. The negative current collector 112 can be a copper foil. The negative active material 113 is provided on the side of the negative current collector 112 facing away from the separator 12.

[0051] Among them, the elongation rate of the composite conductive layer 105 is greater than that of the first current collector layer 104. The elongation rate of the composite conductive layer 105 refers to that a composite conductive layer 105 of a certain size is subjected to a tensile test under certain conditions. The elongation rate of the composite conductive layer 105 is the increment of the length when the composite conductive layer 105 is just broken divided by the initial length of the composite conductive layer 105, that is, the percentage of the increment of the length when the composite conductive layer 105 is broken relative to the initial length. The elongation rate of the first current collector layer 104 refers to that a first current collector layer 104 of the same size (the same size as the composite conductive layer 105) is subjected to a tensile test under the same conditions (the same conditions as those when the composite conductive layer 105 is subjected to a tensile test). The elongation rate of the first current collector layer 104 is the increment of the length when the first current collector layer 104 is just broken divided by the initial length of the first current collector layer 104, that is, the percentage of the increment of the length when the first current collector layer 104 is broken relative to the initial length. The fact that the elongation rate of the composite conductive layer 105 is greater than that of the first current collector layer 104 can be understood as that the composite conductive layer 105 is not easily broken relative to the first current collector layer 104 and has good extensibility. In one embodiment, the elongation rate of the composite conductive layer 105 is greater than or equal to 120%. Of course, in other embodiments, the elongation rate of the composite conductive layer 105 can be 120%-300%.

[0052] Among them, please refer to Figure 8 and Figure 9 , the composite conductive layer 105 may include a heating element 14. In other words, the heating element 14 is disposed in the composite conductive layer 105 of the positive electrode plate 10 so that the positive electrode plate 10 has the function of heating the battery 1. Of course, in other embodiments, the heating element 14 may also be disposed on the side of the composite conductive layer 105 facing away from the first current collector layer 104, or between the composite conductive layer 105 and the first current collector layer 104. It can be understood that the composite conductive layer 105 can generate Joule heat when conducting electricity, thereby increasing the temperature of the entire battery 1. In this embodiment, by disposing the heating element 14 in the composite conductive layer 105, the composite conductive layer 105 can have good elongation performance and can also increase the temperature inside the battery 1 and improve the chemical reaction rate inside the battery 1. In addition, the composite conductive layer 105 has electrical conductivity and can be used to improve the static conductivity of the positive current collector 102 and the current collection performance of the positive current collector 102, so that the battery 1 has a high energy density.

[0053] In another embodiment, such as Figure 10As shown, the positive current collector 102 is an aluminum foil. The positive active material 103 is provided on one side of the aluminum foil facing the separator 12 and on one side of the aluminum foil facing away from the separator 12. The negative current collector 112 includes a first current collecting layer 104 and a composite conductive layer 105. The first current collecting layer 104 and the composite conductive layer 105 are stacked. The composite conductive layer 105 is located on the side of the first current collecting layer 104 facing the separator 12. The negative active material 113 is provided on the side of the first current collecting layer 104 facing away from the composite conductive layer 105. Among them, the elongation rate of the composite conductive layer 105 is greater than that of the first current collecting layer 104. In this embodiment, the elongation rate of the composite conductive layer 105 being greater than that of the first current collecting layer 104 has the same meaning as that in the above embodiment and will not be elaborated here.

[0054] Among them, please refer to Figure 9 and Figure 10 , the composite conductive layer 105 may include a heating element 14. In other words, the heating element 14 is provided in the composite conductive layer 105 of the negative electrode plate 11 so that the negative electrode plate 11 has the function of heating the battery 1. Of course, in other embodiments, the heating element 14 may also be provided on the side of the composite conductive layer 105 facing away from the first current collecting layer 104, or between the composite conductive layer 105 and the first current collecting layer 104. It can be understood that the composite conductive layer 105 can generate Joule heat when conducting electricity, thereby increasing the temperature of the entire battery 1.

[0055] In another embodiment, as Figure 11 shown, the positive current collector 102 includes a first current collecting layer 104 and a first composite conductive layer 105. The first current collecting layer 104 and the first composite conductive layer 105 are stacked. The first composite conductive layer 105 is located on the side of the first current collecting layer 104 facing the separator 12. The positive active material 103 is provided on the side of the first current collecting layer 104 facing away from the composite conductive layer 105. The first current collecting layer 104 may be an aluminum foil. The negative current collector 112 includes a second current collecting layer 106 and a second composite conductive layer 107. The second current collecting layer 106 and the second composite conductive layer 107 are stacked. The second composite conductive layer 107 is located on the side of the second current collecting layer 106 facing the separator 12. The negative active material 113 is provided on the side of the second current collecting layer 106 facing away from the second composite conductive layer 107.

[0056] Among them, the elongation rate of the first composite conductive layer 105 is greater than that of the first current collector layer 104. The elongation rate of the second composite conductive layer 107 is greater than that of the second current collector layer 106. The fact that the elongation rate of the first composite conductive layer 105 is greater than that of the first current collector layer 104 means that when a tensile test is carried out under the same size and the same conditions, the percentage of the increment of the length of the first composite conductive layer 105 when it is broken relative to its initial length is greater than the percentage of the increment of the length of the first current collector layer 104 when it is broken relative to its initial length. The fact that the elongation rate of the second composite conductive layer 107 is greater than that of the second current collector layer 106 means that when a tensile test is carried out under the same size and the same conditions, the percentage of the increment of the length of the second composite conductive layer 107 when it is broken relative to its initial length is greater than the percentage of the increment of the length of the second current collector layer 106 when it is broken relative to its initial length. In one embodiment, the first composite conductive layer 105, the first current collector layer 104, the second composite conductive layer 107 and the second current collector layer 106 have the same size, and the elongation rate of the first composite conductive layer 105 is greater than or equal to that of the second composite conductive layer 107 which is greater than or equal to that of the first current collector layer 104 which is greater than or equal to that of the second current collector layer 106, or the elongation rate of the first composite conductive layer 105 is greater than or equal to that of the first current collector layer 104 which is greater than or equal to that of the second composite conductive layer 107 which is greater than or equal to that of the second current collector layer 106. In another embodiment, the first composite conductive layer 105, the first current collector layer 104, the second composite conductive layer 107 and the second current collector layer 106 have the same size, and the elongation rate of the second composite conductive layer 107 is greater than or equal to that of the first composite conductive layer 105 which is greater than or equal to that of the second current collector layer 106 which is greater than or equal to that of the first current collector layer 104, or the elongation rate of the second composite conductive layer 107 is greater than or equal to that of the second current collector layer 106 which is greater than or equal to that of the first composite conductive layer 105 which is greater than or equal to that of the first current collector layer 104. The above are several elongation rate relationships between the first composite conductive layer 105, the first current collector layer 104, the second composite conductive layer 107 and the second current collector layer 106 listed in this embodiment. It can be understood that the elongation rate relationships between the first composite conductive layer 105, the first current collector layer 104, the second composite conductive layer 107 and the second current collector layer 106 in this application include but are not limited to those listed in the above embodiments. Of course, in other embodiments, on the premise that the elongation rate relationship is satisfied per unit area, the sizes of the first composite conductive layer 105, the first current collector layer 104, the second composite conductive layer 107 and the second current collector layer 106 can be different.

[0057] Among them, please refer to Figure 9 and Figure 11, the first composite conductive layer 105 may include the heating element 14, or the second composite conductive layer 107 may include the heating element 14 in the above embodiments, or the first composite conductive layer 105 includes a first heating element and the second composite layer includes a second heating element. In other words, the first composite conductive layer 105 functions to heat the battery 1, or the second composite conductive layer 107 functions to heat the battery 1, or both the first composite conductive layer 105 and the second composite conductive layer 107 function to heat the battery 1. It can be understood that when the first composite conductive layer 105 and / or the second composite conductive layer 107 are conducting, Joule heat can be generated, thereby increasing the temperature of the entire battery 1.

[0058] By providing the composite conductive layer 105 within the positive current collector 102 and / or the negative current collector 112 such that the elongation rate of the composite conductive layer 105 is greater than that of the first current collecting layer 104, when the positive current collector 102 and / or the negative current collector 112 are mechanically damaged, due to the higher elongation rate of the composite conductive layer 105, it can undergo a large tensile deformation, thereby reducing the likelihood of the positive current collector 102 and / or the negative current collector 112 being punctured. In addition, the composite conductive layer 105 has conductivity, reducing the internal resistance of the positive current collector 102 and / or the negative current collector 112, thereby ensuring the energy density of the positive current collector 102 and / or the negative current collector 112 and improving the current collecting performance of the positive current collector 102 and / or the negative current collector 112. Further, the composite conductive layer 105 also functions to increase the internal temperature of the battery 1, capable of accelerating the chemical reactions inside the battery 1 and reducing the occurrence of lithium plating on the negative electrode. In other words, heating the battery 1 by the composite conductive layer 105 can reduce the piercing of the separator when the positive current collector 102 and / or the negative current collector 112 are mechanically damaged.

[0059] Further, please refer to Figure 11 and Figure 12 , the electronic device 100 further includes a heating circuit 7. The heating circuit 7 is disposed within the accommodation space 5.

[0060] When a lithium-ion battery is in a low-temperature environment, the reaction rate inside it decreases, and lithium plating on the negative electrode may even occur. The precipitated lithium dendrites are prone to piercing the separator, leading to safety issues. Therefore, by providing the heating element 14 within the battery 1, the heating element 14 can be connected to the heating circuit 7 to heat the battery 1 in a low-temperature environment, thereby ensuring the safety of the battery 1 when used in a low-temperature environment. It can be understood that heating the battery 1 by providing the heating element 14 can reduce the possibility of the separator 12 being damaged.

[0061] In one embodiment, as Figure 13As shown, the heating circuit 7 is used to connect the battery 1 and the heating element 14. Specifically, the heating element 14 is provided with a first heating electrode 140 and a second heating electrode 141. The heating circuit 7 is used to connect the positive electrode 101 of the battery 1 to the first heating electrode 140, and connect the negative electrode 110 of the battery 1 to the second heating electrode 141. The heating element 14 is heated by discharging the battery 1. In this embodiment, a heating loop is formed among the battery 1, the heating circuit 7, and the heating element 14.

[0062] In another embodiment, please refer to Figure 12 and Figure 14 , the heating circuit 7 is used to connect the heating element 14 and an external power source. Specifically, the middle frame 3 of the electronic device 100 is further provided with a heating interface 31. The heating interface 31 and the charging interface 30 can be independent interfaces or integrated into one. This embodiment will be described by taking the heating interface 31 and the charging interface 30 being integrated into one. When an external power source is connected to the heating interface 31, the heating element 14 can be conducted with the external power source through the heating circuit 7 and the heating interface 31, and the battery 1 can be conducted with the external power source through the charging circuit 6 and the charging interface 30. Among them, the heating circuit 7 can be provided with a first switch to control whether to heat. The charging circuit 6 can be provided with a second switch to control whether to charge. In one implementation manner, when an external power source is connected to the heating interface 31, the heating circuit 7 and the charging circuit 6 are conducted simultaneously, and while the battery 1 is being charged, the heating element 14 heats the battery 1. In another implementation manner, when an external power source is connected to the heating interface 31, the heating circuit 7 is conducted first, and the heating element 14 pre-heats the battery 1. When the temperature of the battery 1 rises to normal temperature, the heating circuit 7 is disconnected. At this time, the charging circuit 6 is conducted, and the external power source can charge the battery 1.

[0063] By arranging the heating element 14 and the heating circuit 7 inside the electronic device 100, current can be input to the heating circuit 7 in a low-temperature environment, and when the current flows to the heating element 14, Joule heat is generated, so as to ensure that the temperature inside the battery 1 is always at normal temperature, which is beneficial to the battery 1 being charged at a higher charging rate. At the same time, it is also beneficial to improve the reaction speed inside the battery 1 and avoid the occurrence of lithium deposition on the negative electrode, resulting in the diaphragm being pierced.

[0064] In the following embodiments, the structure of the current collector provided in the present application will be specifically described by taking the positive current collector 102 in the positive electrode plate 10 as an example. It can be understood that the solutions described in the following embodiments are applicable to the negative current collector 112 in the negative electrode plate 11.

[0065] In one embodiment, as Figure 15As shown in the figure, the current collector 102 includes a first current collecting layer 104, a composite conductive layer 105, and a second current collecting layer 106. The first current collecting layer 104, the composite conductive layer 105, and the second current collecting layer 106 are stacked in sequence. The elongation rate of the composite conductive layer 105 is greater than that of the first current collecting layer 104, or the elongation rate of the composite conductive layer 105 is greater than that of the second current collecting layer 106, or the elongation rate of the composite conductive layer 105 is greater than that of the first current collecting layer 104 and the second current collecting layer 106. Optionally, the first current collecting layer 104 and the second current collecting layer 106 are aluminum foils with the same thickness. The composite conductive layer 105 is used to undergo a large tensile deformation when the current collector is mechanically damaged, thereby reducing the possibility of the current collector 102 being punctured and for improving the electrical conductivity of the current collector 102 and increasing the energy density of the current collector 102. In addition, the composite conductive layer 105 is also used to release heat in a low-temperature environment, improve the reaction rates of the positive and negative electrodes, and reduce lithium deposition on the negative electrode. Optionally, a first active material 103a is provided on one side of the first current collecting layer 104 facing away from the composite conductive layer 105, and a second active material 103b is provided on one side of the second current collecting layer 106 facing away from the composite conductive layer 105. Among them, the composite conductive layer 105 can be compounded with the first current collecting layer 104 and the second current collecting layer 106 by at least one of coating, rolling, calendering, bonding, evaporation coating, vapor deposition, chemical deposition, magnetron sputtering, electroless plating, etc.

[0066] Optionally, the first active material 103a and the second active material 103b can be at least one of lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium oxide phosphate, lithium cobaltate, lithium manganate, lithium nickelate, lithium nickel cobalt manganate, lithium-rich manganese-based material, lithium nickel cobalt aluminate, graphite, silicon monoxide, tin oxide, lithium titanate, etc.

[0067] By arranging multiple layers of active materials, more lithium ions and electric charges can be stored. By disposing the composite conductive layer 105 between the first current collecting layer 104 and the second current collecting layer 106, on the basis of meeting the mechanical strength of the current collector 102, the thicknesses of the first current collecting layer 104 and the second current collecting layer 106 can be reduced. The reduction in the thicknesses of the first current collecting layer 104 and the second current collecting layer 106 can reduce the burr size generated when they are mechanically damaged, thereby avoiding the diaphragm 12 from being punctured and reducing the risk of short circuit.

[0068] Further, as Figure 16 shown in the figure, the current collector 102 further includes a tab 108. One end of the tab 108 is electrically connected to the first current collecting layer 104, the composite conductive layer 105, and the second current collecting layer 106, and the other end of the tab 108 is connected to a charging circuit 6 (refer to Figure 12) It can be understood that the external current flows into the first current collector layer 104, the composite conductive layer 105, and the second current collector layer 106 through the tab 108, or the current on the first current collector layer 104, the composite conductive layer 105, and the second current collector layer 106 flows out through the tab 108. Optionally, the tab 108 is welded to the first current collector layer 104, the composite conductive layer 105, and the second current collector layer 106. By welding the tab 108 to the first current collector layer 104, the composite conductive layer 105, and the second current collector layer 106 compared with the way of welding the tab 108 to the first current collector layer 104 and the second current collector layer 106, the process difficulty can be reduced. In addition, the composite conductive layer 105 has electrical conductivity and is welded to the tab 108, which will not significantly increase the internal resistance of the current collector 102.

[0069] Among them, as Figure 17 shown, the composite conductive layer 105 includes a conductive part 105a and an adhesive part 105b. It can be understood that when the conductive part 105a is electrically connected to the heating circuit 7 (refer to Figure 12 ), Joule heat is generated to increase the temperature on the current collector 102. The conductive part 105a can be electrically connected to the tab 108 to transfer electrons to the tab 108.

[0070] The conductive part 105a is electrically connected to the first current collector layer 104 and / or the second current collector layer 106. In one embodiment, the conductive part 105a is electrically connected to the first current collector layer 104. Optionally, the conductive part 105a is directly electrically connected to the first current collector layer 104 or the conductive part 105a is connected to the first current collector layer 104 through other objects with electrical conductivity. The direct electrical connection between the conductive part 105a and the first current collector layer 104 can be that the outer surface of the conductive part 105a is in direct contact with the outer surface of the first current collector layer 104.

[0071] In another embodiment, the conductive part 105a is electrically connected to the second current collector layer 106. Optionally, the conductive part 105a is directly electrically connected to the second current collector layer 106 or the conductive part 105a is connected to the second current collector layer 106 through other objects with electrical conductivity. The direct electrical connection between the conductive part 105a and the second current collector layer 106 can be that the outer surface of the conductive part 105a is in direct contact with the outer surface of the second current collector layer 106.

[0072] In yet another embodiment, one end of the conductive part 105a is electrically connected to the first current collector layer 104, and the other end of the conductive part 105a is electrically connected to the second current collector layer 106. Optionally, one end of the conductive part 105a is directly electrically connected to the first current collector layer 104, and the other end of the conductive part 105a is directly electrically connected to the second current collector layer 106.

[0073] Among them, the conductive part 105a can be a conductive plate, a conductive column, a conductive grid 105k, a patterned conductive member 105e, etc. The material of the conductive part 105a can include carbon nanotubes, graphene, conductive graphite, carbon black, carbon fiber, graphite, metal powder, conductive ceramic powder, composite conductive material; lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium oxyphosphate, lithium cobaltate, lithium manganate, lithium nickelate, lithium nickel cobalt manganate, lithium-rich manganese-based material, lithium nickel cobalt aluminate, graphite, silicon monoxide, tin oxide, lithium titanate; at least one of aluminum, copper, nickel, cobalt, tungsten, tin, lead, iron, silver, gold, platinum or their alloys.

[0074] The elongation rate of the conductive part 105a can be greater than or equal to the elongation rates of the first current collector layer 104 and the second current collector layer 106. Of course, in other embodiments, the elongation rate of the conductive part 105a can also be less than the elongation rates of the first current collector layer 104 and the second current collector layer 106.

[0075] The bonding part 105b connects the conductive part 105a, the first current collector layer 104 and the second current collector layer 106. It can be understood that the bonding part 105b is used to fix the conductive part 105a between the first current collector layer 104 and the second current collector layer 106. The material of the bonding part 105b can include at least one of vinylidene fluoride, copolymer of vinylidene fluoride and fluorinated olefin, polytetrafluoroethylene, sodium carboxymethyl cellulose, styrene-butadiene rubber, polyurethane, fluorinated rubber, polyvinyl alcohol, polyvinylidene fluoride, polyamide.

[0076] The elongation rate of the bonding part 105b is greater than the elongation rates of the first current collector layer 104, the conductive part 105a and the second current collector layer 106. It can be understood that the bonding part 105b has good adhesiveness and elongation performance. When the first current collector layer 104 of the current collector is mechanically damaged, the bonding part 105b is stretched and deformed under the action of external force, thereby preventing the current collector 102 from being punctured.

[0077] By electrically connecting the conductive part 105a with the first current collector layer 104 and the second current collector layer 106 in the composite conductive layer 105, the current collection performance of the current collector 102 can be improved, and it is also used to increase the temperature of the current collector 102 and facilitate the welding of the tab 108. By providing the bonding part 105b in the composite conductive layer, the bonding part 105b has adhesiveness and good elongation performance, which can prevent the current collector 102 from being punctured or prevent the burrs on the current collector 102 from puncturing the separator 12.

[0078] In one embodiment, please refer to Figure 17 and Figure 18, the bonding portion 105b includes a first sub-bonding portion 105c and a second sub-bonding portion 105d. The first current collector layer 104, the first sub-bonding portion 105c, the conductive portion 105a, the second sub-bonding portion 105d, and the second current collector layer 106 are sequentially stacked. Specifically, the outer surface of the first sub-bonding portion 105c includes a first bonding surface 1051 and a second bonding surface 1052 that are oppositely arranged. The first current collector layer 104 is directly bonded to the first bonding surface 1051 of the bonding portion 105b, and the side of the conductive portion 105a facing the first current collector layer 104 is directly bonded to the second bonding surface 1052 of the bonding portion 105b. The outer surface of the second sub-bonding portion 105d includes a third bonding surface 1053 and a fourth bonding surface 1054 that are oppositely arranged. The side of the conductive portion 105a facing the second current collector layer 106 is directly bonded to the third bonding surface 1053 of the bonding portion 105b, and the second current collector layer 106 is directly bonded to the fourth bonding surface 1054 of the bonding portion 105b.

[0079] In this embodiment, by sequentially stacking the first current collector layer 104, the first sub-bonding portion 105c, the conductive portion 105a, the second sub-bonding portion 105d, and the second current collector layer 106, and connecting the first current collector layer 104 and the conductive portion 105a through the first sub-bonding portion 105c, and connecting the second current collector layer 106 and the second sub-bonding portion 105d through the second sub-bonding portion 105d, the process can be simplified and the production efficiency can be improved. The conductive portion 105a is electrically connected to the first current collector layer 104 and the second current collector layer 106 through bent conductive wires.

[0080] In another embodiment, as Figure 19 shown, the bonding portion 105b is filled between the first current collector layer 104 and the second current collector layer 106. The conductive portion 105a includes a plurality of spaced-apart conductive posts that penetrate the bonding portion 105b. Optionally, the conductive posts pass through the bonding portion 105b. Specifically, the bonding portion 105b includes a first bonding surface 1051 and a second bonding surface 1052 that are oppositely arranged. The first bonding surface 1051 directly contacts the surface of the first current collector layer 104. The second bonding surface 1052 directly contacts the surface of the second current collector layer 106. One end of the conductive post is flush with the first bonding surface 1051, and the other end of the conductive post is flush with the second bonding surface 1052. It can be understood that one end of the conductive post directly contacts the first current collector layer 104, and the other end of the conductive post directly contacts the second current collector layer 106, so that the first current collector layer 104, the conductive portion 105a, and the second current collector layer 106 are sequentially electrically connected. Optionally, the conductive posts can partially penetrate the bonding portion 105b. Specifically, both ends of the conductive post are located within the bonding portion 105b. The plurality of conductive posts can be sequentially connected in series within the bonding portion 105b and then electrically connected to the first current collector layer 104 and the second current collector layer 106.

[0081] By connecting multiple conductive posts in series, it is convenient to control the multiple conductive posts and improve the conductivity of the conductive part 105a. As a result, the conductive part 105a, the first current collector layer 104, and the second current collector layer 106 can collect a relatively large amount of current output. In this embodiment, by arranging the conductive posts in the bonding part 105b, the thickness of the composite conductive layer 105 can be reduced, and the energy density of the battery 1 can be increased.

[0082] In another embodiment, please refer to Figure 20 and Figure 21 , the conductive part 105a includes a patterned conductive member 105e, the bonding part 105b includes an adhesive member 105f complementary to the pattern of the conductive member 105e, and the conductive member 105e and the adhesive member 105f are arranged on the same layer between the first current collector layer 104 and the second current collector layer 106. One end of the conductive part 105a is connected to the first current collector layer 104, and the other end of the conductive part 105a is connected to the second current collector layer 106. Optionally, one end of the conductive part 105a is welded to the first current collector layer 104, and the other end of the conductive part 105a is welded to the second current collector layer 106. Optionally, a first electrical connection post 105g is provided at one end of the conductive part 105a, and a second electrical connection post 105h is provided at the other end of the conductive part 105a. The first electrical connection post 105g connects the conductive part 105a to the first current collector layer 104. The second electrical connection post 105h connects the conductive part 105a to the second current collector layer 106. In this embodiment, the first electrical connection post 105g can be connected to the edge of the conductive part 105a and the second electrical connection post 105h, and the second electrical connection post 105h can be connected to the edge of the conductive part 105a and the second electrical connection post 105h, so that the first current collector layer 104 and the second current collector layer 106 are led out through the first electrical connection post 105g and the second electrical connection post 105h. In other words, the lead tab 108 can be welded to the first electrical connection post 105g and the second electrical connection post 105h.

[0083] In yet another embodiment, please refer to Figure 22 and Figure 23 , the conductive part 105a includes a conductive grid 105k, the bonding part 105b includes an adhesive 105m filled in the gaps of the conductive grid 105k, and the conductive grid 105k is laid flat on the first current collector layer 104. Specifically, the conductive part 105a includes a plurality of first conductive wires 105i arranged horizontally and a plurality of second conductive wires 105j arranged vertically, and the first conductive wires 105i and the second conductive wires 105j are electrically connected. A plurality of first conductive wires 105i are electrically connected to the first current collector layer 104, and a plurality of second conductive wires 105j are electrically connected to the second current collector layer 106. In this embodiment, the structure of the conductive part 105a is simple, the process can be simplified, and the production efficiency can be improved.

[0084] In another example, as Figure 24As shown, the current collector 102 includes a first current collecting layer 104, a composite conductive layer 105, and a second current collecting layer 106. The first current collecting layer 104, the composite conductive layer 105, and the second current collecting layer 106 are stacked in sequence.

[0085] Among them, the composite conductive layer 105 includes an adhesive layer 1055 and conductive particles 1056 disposed on the adhesive layer 1055.

[0086] In one embodiment, as Figure 24 shown, the conductive particles 1056 are distributed within the adhesive layer 1055. Optionally, after the conductive particles 1056 are mixed with the adhesive 105m, a composite conductive layer 105 is formed on the surface of the first current collecting layer 104. It can be understood that the conductive particles 1056 have electrical conductivity. In other words, the conductive particles 1056 can be used to converge the microcurrent of the active material, thereby improving the current collection ability of the current collector.

[0087] In another embodiment, as Figure 25 shown, the conductive particles 1056 are distributed on the outer surface of the adhesive layer 1055. Specifically, the outer surface of the adhesive layer 1055 includes a first adhesive surface 1051 and a second adhesive surface 1052 that are oppositely arranged. The first current collecting layer 104 is directly adhered to the first adhesive surface 1051 of the adhesive portion 105b, and the second current collecting layer 106 is directly adhered to the second adhesive surface 1052 of the adhesive portion 105b. The conductive particles 1056 are distributed on the first adhesive surface 1051, or the conductive particles 1056 are distributed on the second adhesive surface 1052, or the conductive particles 1056 are partially distributed on the first adhesive surface 1051 and the other part is distributed on the second adhesive surface 1052. It can be understood that the conductive particles 1056 distributed on the first adhesive surface 1051 are in direct contact with the first current collecting layer 104, which can improve the electrical conductivity of the first current collecting layer 104, so that the first current collecting layer 104 can collect more current. The conductive particles 1056 distributed on the second adhesive surface 1052 are in direct contact with the second current collecting layer 106, which can improve the electrical conductivity of the second current collecting layer 106, so that the second current collecting layer 106 can collect more current. In this embodiment, the conductive particles 1056 can be coated on the outer surface of the adhesive layer 1055.

[0088] By providing the conductive particles 1056 in the composite conductive layer 105, the current collection performance of the current collector 102 can be improved. By providing the adhesive layer 1055 in the composite conductive layer, the adhesive layer 1055 has viscosity and good extensibility, which can prevent the current collector 102 from being pierced, or prevent the burrs on the current collector 102 from piercing the separator 12.

[0089] Furthermore, as Figure 26 shown, the composite conductive layer 105 further includes magnetic particles 1057.

[0090] In one embodiment, the magnetic particles 1057 and the conductive particles 1056 are mixed and distributed in the adhesive layer 1055. Optionally, after the conductive particles 1056, the magnetic particles 1057 and the adhesive 105m are mixed, a composite conductive layer 105 is formed on the surface of the first current collector layer 104. Among them, the conductive particles 1056 are used to improve the conductivity of the composite conductive layer 105. The magnetic particles 1057 are used to gather at the position where the external metal needle pierces the composite conductive layer 105, so as to prevent the external metal from piercing the current collector.

[0091] By providing the magnetic particles 1057 in the composite conductive layer 105, the magnetic particles 1057 can converge around the metal needle when the current collector 102 is subjected to a needle piercing test, forming a barrier, so as to prevent the composite conductive layer 105 from being pierced.

[0092] In another embodiment, as Figure 27 shown, the magnetic particles 1057 are distributed on the outer surface of the adhesive layer 1055. Optionally, the outer surface of the adhesive layer 1055 includes a first adhesive surface 1051 and a second adhesive surface 1052 which are oppositely arranged. The first current collector layer 104 is directly bonded to the first adhesive surface 1051 of the bonding portion 105b, and the second current collector layer 106 is directly bonded to the second adhesive surface 1052 of the bonding portion 105b. The conductive particles 1056 are distributed on the first adhesive surface 1051, and the magnetic particles 1057 are distributed on the second adhesive surface 1052. When an external metal needle pierces the composite conductive layer 105, the magnetic particles 1057 gather at the stressed position of the composite conductive layer 105 on the second adhesive surface 1052. Thus, a barrier is formed at the stressed position, so that even if the external metal pierces the first current collector layer 104 and the bonding portion 105b, it cannot pass through the magnetic particles 1057 to pierce the second current collector layer 106.

[0093] Through the structural design of the current collector in the present application, a composite conductive layer is interposed between multiple current collector layers. The composite conductive layer can improve the viscosity, ductility and conductivity of the current collector, and can improve the mechanical strength of the current collector on the premise of ensuring that the current collector has a high energy density, and prevent the current collector from being damaged. When magnetic particles are provided in the composite conductive layer, it can further prevent metal substances from piercing the composite conductive layer by the magnetic particles while ensuring the viscosity of the composite conductive layer. In addition, the composite conductive layer can also increase the temperature of the current collector, which is beneficial to the rapid charging of the battery and reduce the possibility of lithium deposition on the outer surface of the current collector and lithium dendrites piercing the separator.

[0094] The above are some embodiments of the present application. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present application, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present application.

Claims

1. A current collector, characterized in that, Comprising: A first current collector layer; And A composite conductive layer, the composite conductive layer being stacked with the first current collector layer, the elongation rate of the composite conductive layer being greater than that of the first current collector layer, the composite conductive layer including an adhesive layer, conductive particles provided on the adhesive layer, and magnetic particles provided on the adhesive layer, the magnetic particles being configured to converge at the position where an external metal needle pierces the composite conductive layer to prevent the external metal from piercing through the composite conductive layer.

2. The current collector according to claim 1, characterized in that, The current collector further includes a tab, and the tab electrically connects the first current collector layer and the composite conductive layer.

3. The current collector according to claim 1, characterized in that, The current collector further includes a second current collector layer, the second current collector layer electrically connecting the first current collector layer and the composite conductive layer, and the first current collector layer, the composite conductive layer, and the second current collector layer being stacked in sequence.

4. The current collector according to claim 1, wherein The first current collector layer includes aluminum foil or copper foil.

5. The current collector according to claim 1, wherein The current collector further includes a heating electrode provided on the composite conductive layer, and the heating electrode is configured to connect to a power source to generate heat in the composite conductive layer.

6. The current collector according to claim 1, characterized in that, The composite conductive layer further includes an active material, and the active material includes at least one of lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium oxyphosphate, lithium cobaltate, lithium manganate, lithium nickelate, lithium nickel cobalt manganate, lithium-rich manganese-based material, lithium nickel cobalt aluminate, graphite, silicon monoxide, tin oxide, and lithium titanate.

7. The current collector according to any one of claims 1 to 6, characterized in that The thickness of the composite conductive layer is 1 μm to 40 μm.

8. A battery, characterized in that, Comprising an electrode sheet, the electrode sheet including the current collector according to any one of claims 1 to 7, a first active material provided on a side of the first current collector layer facing away from the composite conductive layer, and a second active material provided on a side of the composite conductive layer facing away from the first current collector layer.

9. An electronic device, characterized in that, Comprising the battery according to claim 8 and a charging circuit, the charging circuit being electrically connected to the electrode sheet.

10. The electronic device according to claim 9, characterized in that, The electronic device further includes a heating circuit, and the heating circuit is electrically connected to the electrode sheet.

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