Current collector, battery and electric equipment

Abstract

The utility model discloses a current collector, a battery and electric equipment. The current collector comprises a base material layer, a conductive layer and a positive temperature coefficient thermistor layer. In the first direction, the base material layer comprises a first surface and a second surface; the conductive layer is arranged on at least one of the first surface and the second surface, and the conductive layer comprises a first end and a second end in the second direction; the positive temperature coefficient thermistor layer is arranged on at least one side, in the first direction, of the conductive layer and makes contact with the conductive layer, the length of the positive temperature coefficient thermistor layer extends from the first end to the second end, and in the third direction, the width of the positive temperature coefficient thermistor layer is smaller than that of the conductive layer. The problem that when the thinned copper foil is used as the current collector, the current collector is likely to generate an overflowing phenomenon is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage devices, in particular to a current collector, a battery and an electric device. BACKGROUND

[0002] In the prior art, lithium ion batteries are widely used in different products and fields, such as notebook computers, portable mobile phones, new energy vehicles, etc., due to their large battery capacity, long cycle life and other advantages. With the update iteration of terminal products, the demand for long cycle and high energy density of batteries is increasing.

[0003] In the production of lithium batteries, copper foil is used as the negative electrode current collector, which has good conductivity and is soft and easy to process. However, due to the high density of copper foil itself, the total weight of the battery accounts for about 8% to 10%, and the industry usually thins the copper foil to reduce the weight of the battery.

[0004] However, as the thickness of the copper foil decreases, the mechanical strength of the copper foil decreases. Therefore, when the thinned copper foil is used as the current collector of the battery, the current collector is prone to overcurrent, increasing the risk of battery combustion and posing a great safety hazard to the battery. UTILITY MODEL CONTENT

[0005] The main purpose of the present application is to provide a current collector, a battery and an electric device to solve the problem of overcurrent of the current collector when the thinned copper foil is used as the current collector in the background art.

[0006] According to one aspect of the present application, a current collector is provided, comprising:

[0007] a substrate layer, along a first direction, the substrate layer comprising a first surface and a second surface;

[0008] a conductive layer, the conductive layer being disposed on at least one of the first surface and the second surface, along a second direction, the conductive layer comprising a first end and a second end;

[0009] a positive temperature coefficient thermistor layer, the positive temperature coefficient thermistor layer being disposed on at least one side of the conductive layer along the first direction and in contact with the conductive layer, the length of the positive temperature coefficient thermistor layer extending from the first end to the second end, and along a third direction, the width of the positive temperature coefficient thermistor layer is less than the width of the conductive layer.

[0010] Further, along the third direction, the conductive layer comprises a first edge and a second edge, and the positive temperature coefficient thermistor layer is provided with a predetermined gap between the first edge and the second edge, respectively.

[0011] Further, the plurality of positive temperature coefficient thermistor layers are arranged on the surface of the substrate layer along a third direction.

[0012] Alternatively, the conductive layer is arranged on the substrate layer and covers the surface of the positive temperature coefficient thermistor layer away from the substrate layer.

[0013] Further, the positive temperature coefficient thermistor layer comprises at least one of a straight line type coating structure or a curved line type coating structure.

[0014] Further, the positive temperature coefficient thermistor layer comprises:

[0015] a main section, a length of the main section extending from the first end to the second end;

[0016] an extension section, a length of the extension section being less than the length of the main section along a second direction, the extension section comprising a plurality of extension sections arranged along the second direction and spaced apart from each other along a third direction of the main section.

[0017] Further, along the third direction, the main section comprises a first side and a second side, the extension sections arranged on the first side and the second side correspond to each other.

[0018] Alternatively, a projection outer contour of the extension sections arranged on the first side is at least partially misaligned with a projection outer contour of the extension sections arranged on the second side along the second direction.

[0019] Further, the positive temperature coefficient thermistor layer comprises:

[0020] a first coating layer arranged on the first surface;

[0021] a second coating layer arranged on the second surface, a width of the first coating layer being equal to a width of the second coating layer.

[0022] Further, the first coating layer and the second coating layer are arranged correspondingly.

[0023] Alternatively, along the first direction, a projection outer contour of the first coating layer is at least partially misaligned with a projection outer contour of the second coating layer along the third direction.

[0024] Further, on the first surface or the second surface of the substrate layer, a maximum distance between two adjacent positive temperature coefficient thermistor layers is between 10 cm and 1000 cm.

[0025] Further, the maximum width of the positive temperature coefficient thermistor layer is between 0.1 μm and 100 mm.

[0026] Further, the current collector further comprises:

[0027] a bonding force enhancement layer disposed on the surface of the substrate layer and between two adjacent positive temperature coefficient thermistor layers, and the conductive layer is disposed on the bonding force enhancement layer and the positive temperature coefficient thermistor layer away from the surface of the substrate layer;

[0028] an oxidation prevention layer disposed on the surface of the conductive layer away from the substrate layer.

[0029] Further, the thickness of the bonding force enhancement layer is between 10 nm and 100 nm in the first direction.

[0030] Further, the thickness of the oxidation prevention layer is between 10 nm and 100 nm in the first direction.

[0031] Further, the substrate layer comprises at least one of a polyethylene layer, a polypropylene layer, a polyimide layer, a glass fiber layer, a cotton layer, a hemp layer, a o-phenylphenol layer, a polyimide layer, a polyethylene terephthalate layer, a chlorinated polypropylene resin layer, a polyvinyl chloride layer, or a Ajinomoto build-up film layer.

[0032] Further, the thickness of the substrate layer is between 0.5 μm and 8 μm in the first direction.

[0033] Further, the thickness of the conductive layer is between 100 nm and 1000 nm in the first direction.

[0034] In another aspect, the application also provides a battery comprising the current collector according to any of the above technical solutions.

[0035] In another aspect, the application also provides a battery comprising the current collector according to any of the above technical solutions.

[0036] In the present application, the positive temperature coefficient thermistor layer arranged on at least one surface of the conductive layer has the characteristic that the resistivity increases rapidly with the increase of temperature, and the resistance of the positive temperature coefficient thermistor layer can increase sharply after the battery overheats, thereby increasing the resistance of the current collector, effectively reducing the risk of overcurrent of the current collector, preventing the temperature of the battery where the current collector is located from continuing to rise, and preventing the battery from overheating. In addition, since the current conduction direction of the current collector is along the third direction (i.e. the width direction of the current collector), when the current collector overheats, in view of the fact that the length of the positive temperature coefficient thermistor layer extends from the first end to the second end of the conductive layer, and the width of the positive temperature coefficient thermistor layer is less than the width of the conductive layer, the positive temperature coefficient thermistor layer can separate the conductive layer into at least two regions along the third direction, effectively increase the resistance of the positive temperature coefficient thermistor layer when the temperature rises, hinder or even block the continuous conduction of the current in the conductive layer along the third direction, thereby limiting the further increase of the current, preventing the temperature of the current collector from continuing to rise, effectively reducing the risk of overcurrent, and further improving the safety performance of the battery using the current collector. The positive temperature coefficient thermistor layer extending along the length direction of the conductive layer can increase the effective area of the positive temperature coefficient thermistor layer on the substrate layer, can provide protection for the current collector in the entire second direction (i.e. the length direction of the current collector), and can more comprehensively monitor the temperature change of the current collector. Even if the current collector overflows and a piercing phenomenon occurs, the positive temperature coefficient thermistor layer can rapidly increase the resistance of the pierced position of the current collector, prevent the current from conducting along the third direction of the current collector, reduce the heat generated when the current collector is short-circuited, reduce the danger caused by the piercing of the current collector, and effectively improve the safety of the battery in use.

[0037] In the third direction, the width of the positive temperature coefficient thermistor layer is less than the width of the conductive layer, so that the conductive layer can be at least partially in direct contact with the substrate layer, ensuring that the interface bonding force between the conductive layer and the substrate layer is good, thereby preventing the conductive layer from being easily separated from the substrate layer under the action of a relatively large adhesion force from the outside, and avoiding that the positive temperature coefficient thermistor layer completely separates the conductive layer from the substrate layer. BRIEF DESCRIPTION OF DRAWINGS

[0038] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application. The schematic embodiments of the present application and the descriptions thereof are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0039] Figure 1 A sectional view of a current collector disclosed in the present application (I);

[0040] Figure 2 A top view of a current collector disclosed in the present application (I);

[0041] Figure 3A cross-sectional view of a current collector disclosed in the present application (II);

[0042] Figure 4 A top view of a current collector disclosed in the present application (II);

[0043] Figure 5 A top view of a current collector disclosed in the present application (III);

[0044] Figure 6 A cross-sectional view of a current collector disclosed in the present application (III);

[0045] Figure 7 A cross-sectional view of a current collector disclosed in the present application (IV).

[0046] Among the above-mentioned drawings, the following reference signs are included:

[0047] 1, substrate layer; 11, first surface; 12, second surface; 2, conductive layer; 21, first end; 22, second end; 23, first edge; 24, second edge; 3, positive temperature coefficient thermistor layer; 31, main section; 311, first side; 312, second side; 32, extension section; 33, first coating layer; 34, second coating layer; 4, adhesion enhancement layer; 5, oxidation prevention layer; 6, predetermined gap. DETAILED DESCRIPTION

[0048] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0049] It should be noted that the terms used herein are only intended to describe specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, there is a presence of the features, steps, operations, devices, components and / or combinations thereof.

[0050] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the examples herein are not meant to limit the scope of the present application unless otherwise specifically stated. Also, it is to be understood that the dimensions of the various parts shown in the drawings are not necessarily to scale as the dimensions can have been exaggerated for the sake of clarity in illustrating the principles of the application. Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail but should be considered as part of the description of the present application where appropriate. In all examples shown and discussed herein, any specific value should be interpreted as merely an example and not a limitation. Thus, other examples of the exemplary embodiments can have different values. It is to be noted that like numbers and letters refer to like elements throughout the several views of the drawings and, as such, no further discussion with regard thereto is needed.

[0051] Referring to Figures 1 to 7 As shown, the present application provides a current collector, comprising a substrate layer 1, a conductive layer 2 and a positive temperature coefficient thermistor layer 3. Wherein, along the first direction (as indicated by the arrow A, specifically the thickness direction of the substrate layer 1), the substrate layer 1 comprises a first surface 11 and a second surface 12. The conductive layer 2 is arranged on at least one of the first surface 11 and the second surface 12. Along the second direction (as indicated by the arrow B, specifically the length direction of the substrate layer 1), the conductive layer 2 comprises a first end 21 and a second end 22. The positive temperature coefficient thermistor layer 3 is arranged on at least one side of the conductive layer 2 along the first direction and in contact with the conductive layer 2, the length of the positive temperature coefficient thermistor layer 3 extends from the first end 21 to the second end 22, and along the third direction (as indicated by the arrow C, specifically the width direction of the substrate layer 1), the width D of the positive temperature coefficient thermistor layer 3 is less than the width of the conductive layer 2. Figure 1 Figure 2 Figure 1

[0052] The positive temperature coefficient thermistor layer 3 in direct contact with the conductive layer 2 can divide the conductive layer 2 into at least two regions along the third direction, at least one region is the region of the conductive layer 2 in contact with the positive temperature coefficient thermistor layer 3, and at least one region is the part of the conductive layer 2 located opposite to the positive temperature coefficient thermistor layer 3. After the resistance of the positive temperature coefficient thermistor layer 3 increases, the resistance of the part of the conductive layer 2 in contact with the positive temperature coefficient thermistor layer 3 can be increased, so that the current of the part of the conductive layer 2 located opposite to the positive temperature coefficient thermistor layer 3 is difficult to conduct to the region of the conductive layer 2 in contact with the positive temperature coefficient thermistor layer 3, thereby the positive temperature coefficient thermistor layer 3 can hinder or even block the current in the conductive layer 2 to continue to conduct along the third direction, effectively preventing the temperature of the battery using the current collector from continuing to rise, and improving the safety performance of the battery. ​​​

[0053] In the present embodiment, the positive temperature coefficient thermistor layer 3 provided on at least one surface of the conductive layer 2 has the characteristic that its resistivity increases rapidly with temperature rise, and the resistance of the positive temperature coefficient thermistor layer 3 can increase sharply after the battery overheats, thereby increasing the resistance of the current collector and effectively reducing the risk of overcurrent of the current collector, preventing the temperature of the battery where the current collector is located from continuing to rise, and thus preventing the battery from overheating. In addition, since the current conduction direction of the current collector is along the third direction, when the current collector has an overcurrent heating phenomenon, in view of the length of the positive temperature coefficient thermistor layer 3 extending from the first end 21 to the second end 22, and the width of the positive temperature coefficient thermistor layer 3 being less than the width of the conductive layer 2, the positive temperature coefficient thermistor layer 3 can separate the conductive layer 2 into at least two regions along the third direction, effectively increase the resistance of the positive temperature coefficient thermistor layer 3 when the temperature rises, hinder or even block the continuous conduction of the current in the conductive layer 2 along the third direction, thereby limiting the further increase of the current, preventing the temperature of the current collector from continuing to rise, effectively reducing the risk of overcurrent, and further improving the safety performance of the battery using the current collector. The positive temperature coefficient thermistor layer 3 extending along the length direction of the conductive layer can increase the effective area of the positive temperature coefficient thermistor layer 3 on the substrate layer 1, and can provide protection for the current collector in the entire second direction, and more comprehensively monitor the temperature change of the current collector. Even if the current collector has a piercing phenomenon due to overcurrent, the positive temperature coefficient thermistor layer 3 can rapidly increase the resistance of the pierced position of the current collector, prevent the current from conducting along the third direction of the current collector, reduce the heat generated when the current collector is short-circuited, reduce the danger caused by the piercing of the current collector, and effectively improve the safety of the battery in use.

[0054] In the third direction, the width of the positive temperature coefficient thermistor layer 3 is less than the width of the conductive layer 2, so that the conductive layer 2 can at least partially directly contact the substrate layer 1, and the interfacial bonding force between the conductive layer 2 and the substrate layer 1 is good, thereby ensuring that the conductive layer 2 is not easily separated from the substrate layer 1 under the action of a large external adhesion force, and avoiding that the positive temperature coefficient thermistor layer 3 completely separates the conductive layer 2 from the substrate layer 1.

[0055] Generally, the positive temperature coefficient thermistor layer 3 is a positive temperature coefficient thermistor material, and the positive temperature coefficient thermistor layer 3 is mainly a film layer structure formed by depositing a PTC thermistor paste coated on the substrate layer 1 (the full name of PTC thermistor in English is Positive Temperature Coefficient, which means positive temperature coefficient, indicating that the resistivity can increase with the increase of temperature). The positive temperature coefficient thermistor layer 3 has the characteristic that the resistivity increases with the increase of temperature. The resistance value of the positive temperature coefficient thermistor layer 3 changes very slowly with the temperature before reaching a certain temperature, and when the temperature exceeds the certain temperature (also known as Curie temperature), the resistance value of the PTC thermistor will increase sharply, which can quickly respond to overload current, and is beneficial to the safety of the current collector and avoids the current collector from overcurrent. And the PTC thermistor has strong impact resistance, long service life, small volume, and can be processed into various shapes and various specifications according to actual needs, which is convenient to set on the surface of the substrate layer 1.

[0056] Specifically, the composition of the positive temperature coefficient thermistor layer 3 can include a high molecular polymer matrix, a conductive agent, inorganic particles, and a carbon-based conductive agent. Among them, the high molecular polymer includes one of low density polyethylene, high density polyethylene, epoxy resin, polyvinylidene fluoride, ethylene-ethyl acrylate copolymer, polybutylene, cellulose acetate, and polyamide. The conductive agent includes one or more of nickel powder, copper powder, aluminum powder, and tungsten carbide. The inorganic particles are selected from one or more of alumina, silica, aluminum hydroxide, and barium titanate. The carbon-based conductive agent is selected from one or more of conductive carbon black (Super-P, Super-S, 350G, etc.), and carbon fiber (VGCF). The positive temperature coefficient thermistor layer 3 can also include a film layer structure formed by coating a PTC thermistor paste composed of epoxy resin, carbon black, and curing agent polyamide on the substrate layer 1.

[0057] As Figure 2As shown, in order to make the blocking effect of the positive temperature coefficient thermistor layer 3 to the current better, in the embodiment, the conductive layer 2 includes a first edge 23 and a second edge 24 along the third direction, and the positive temperature coefficient thermistor layer 3 is provided with a predetermined gap 6 between the first edge 23 and the second edge 24, respectively. Therefore, when the positive temperature coefficient thermistor layer 3 is provided with the predetermined gap 6 between the first edge 23 and the second edge 24, respectively, the conductive layer 2 can be divided into at least two non-contact areas and at least one contact area along the third direction, the non-contact area is the area where the conductive layer 2 is located in the positive temperature coefficient thermistor layer 3, and the contact area is the area where the conductive layer 2 contacts the positive temperature coefficient thermistor layer 3. Therefore, the contact area can completely isolate the non-contact area, and since the resistance of the contact area will increase when the temperature of the battery rises, the current in the non-contact area is difficult to conduct from the contact area to another non-contact area, so that the positive temperature coefficient thermistor layer 3 can timely and effectively hinder the current from one non-contact area to another non-contact area along the third direction, thereby reducing the current and preventing the temperature of the battery where the current collector is located from continuing to rise, preventing the battery from overheating.

[0058] In order to realize that the positive temperature coefficient thermistor layer 3 can effectively hinder the conduction of the current while improving the effective range of the positive temperature coefficient thermistor layer 3 to the current collector. In one embodiment, the positive temperature coefficient thermistor layer 3 includes a plurality of positive temperature coefficient thermistor layers 3, and the plurality of positive temperature coefficient thermistor layers 3 are arranged on the surface of the substrate layer 1 along the third direction and are spaced apart from each other, and the conductive layer 2 is arranged on the surface of the substrate layer 1 and is located between two adjacent positive temperature coefficient thermistor layers 3. The plurality of positive temperature coefficient thermistor layers 3 are arranged at intervals, which is beneficial to generate a larger resistance and is beneficial to quickly reduce the current.

[0059] Moreover, the plurality of positive temperature coefficient thermistor layers 3 arranged at intervals along the third direction can divide the conductive layer 2 into a plurality of non-contact areas and a plurality of contact areas along the third direction, and the plurality of contact areas can hinder the conduction of the current in the conductive layer 2 along the third direction multiple times, reducing the risk of the current collector being pierced.

[0060] Preferably, multiple positive temperature coefficient (PTC) thermistor layers 3 can be spaced apart and uniformly arranged along a third direction to uniformly slow down the temperature rise rate of the current collector. This effectively avoids a situation where the temperature rise rate of the current collector region with a dense distribution of PTC thermistor layers 3 is lower than that of the current collector region with a sparse distribution of PTC thermistor layers 3. It also facilitates processing and ensures consistent quality control of downstream products (such as batteries). This is because if the multiple PTC thermistor layers 3 are uniformly distributed on the substrate layer 1, the performance differences between batteries will be smaller, which is beneficial for battery manufacturers to control the consistency of battery quality. Therefore, in this embodiment, uniformly arranging multiple PTC thermistor layers 3 on the substrate layer 1 can ensure the consistency of downstream product quality and also help improve the uniformity of heat distribution on the PTC thermistor layers 3, which is beneficial for optimizing heat distribution, ensuring relatively uniform heat distribution of the current collector, and further improving the safety of the battery with this current collector.

[0061] Furthermore, when multiple positive temperature coefficient (PTC) thermistor layers 3 are disposed on the surface of the substrate layer 1, after the coating tool for coating the PTC thermistor layers 3 is positioned at a specific location, during the unwinding process of the substrate layer 1, each part of the substrate layer 1 passes through the coating tool sequentially, thereby achieving the coating of the PTC thermistor layers 3. This process is convenient and efficient. In addition, the uniform distribution of the PTC thermistor layers 3 can uniformly slow down the temperature rise rate of the current collector, effectively avoiding a situation where the temperature rise rate of the densely distributed current collector area is lower than that of the sparsely distributed current collector area. This reduces the impact of uneven temperature rise rates on the electrochemical performance of the battery and ensures the consistency of downstream product quality.

[0062] Or, such as Figure 3 As shown, in another embodiment, the conductive layer 2 can also be disposed on the substrate layer 1 and cover the surface of the positive temperature coefficient thermistor layer 3 away from the substrate layer 1. This is beneficial to ensure the stability of the positive temperature coefficient thermistor layer 3 and prevent relative displacement. It is also beneficial to improve the interfacial bonding force between the conductive layer 2 and the substrate layer 1 and ensure the stability and reliability of the conductive layer 2.

[0063] In this embodiment, since the positive temperature coefficient thermistor layer 3 is located between the conductive layer 2 and the substrate layer 1 and is covered by the conductive layer 2, the positive temperature coefficient thermistor layer 3 will not affect the contact between the current collector and the active material layer, which is beneficial to ensuring the reliability of current conduction.

[0064] like Figure 2As shown, in one embodiment, the positive temperature coefficient thermistor layer 3 includes a linear coating structure. The linear coating structure is perpendicular to the first end 21 and the second end 22, which facilitates the processing of the positive temperature coefficient thermistor layer 3 and reduces the processing difficulty.

[0065] In another embodiment, when the positive temperature coefficient thermistor layer 3 is configured as a linear coating structure, the positive temperature coefficient thermistor layer 3 can be tilted at the first end 21 and the second end 22, which can increase the effective area of ​​the positive temperature coefficient thermistor layer 3 on the substrate layer 1, reduce the current when the current collector is short-circuited, and quickly prevent the battery temperature from continuing to rise.

[0066] like Figure 4 As shown, in another embodiment, the positive temperature coefficient (PTC) thermistor layer 3 can be configured as a curved coating structure to further increase the effective area of ​​the PTC thermistor layer 3 on the substrate layer 1. Therefore, the mutually spaced curved PTC thermistor layers 3 can further reduce the current during a short circuit of the current collector while ensuring a tighter bond between the conductive layer 2 and the substrate layer 1. Furthermore, when the current collector is punctured, the curved coating structure can cover more puncture sites to increase the resistance at the puncture point and reduce the safety hazards caused by the current collector being punctured.

[0067] The above embodiments can be implemented individually or simultaneously. That is, the positive temperature coefficient thermistor layer 3 can be partially configured as a linear coating structure and partially configured as a curved coating structure, depending on the actual situation.

[0068] like Figure 5 As shown, in one embodiment, the positive temperature coefficient thermistor layer 3 includes a main body segment 31 and an extension segment 32. The length of the main body segment 31 extends from a first end 21 to a second end 22. Along the second direction, the length of the extension segment 32 is less than the length of the main body segment 31. The extension segment 32 includes multiple segments, which are spaced apart from each other along the second direction on at least one side of the main body segment 31 along the third direction. The extension segment 32 can increase the effective area of ​​the positive temperature coefficient thermistor layer 3 on the substrate layer 1, cover more puncture sites to increase the resistance of the puncture points, and effectively hinder or even block the conduction of current along the third direction, further improving the safety of the battery equipped with the current collector.

[0069] In one embodiment, along a third direction, the main body segment 31 includes a first side 311 and a second side 312, both the first side 311 and the second side 312 are provided with extension segments 32, and the extension segments 32 located on the first side 311 and the extension segments 32 located on the second side 312 are provided in a one-to-one correspondence. This facilitates mass production and processing, and helps to ensure the uniformity of mechanical strength of various parts of the current collector.

[0070] Alternatively, in another embodiment, the projected outer contour of the extension 32 located on the first side 311 is at least partially offset along the second direction from the projected outer contour of the extension 32 on the second side 312. This is beneficial for increasing the effective area of ​​the positive temperature coefficient thermistor layer 3 on the current collector, enabling it to more quickly and effectively impede current conduction and rapidly prevent the battery temperature from continuing to rise.

[0071] Alternatively, in another embodiment, the above embodiments can be implemented simultaneously, with the extension segment 32 located on the first side 311 and the extension segment 32 located on the second side 312 partially corresponding one-to-one and partially interleaved. This embodiment is not limited to a single embodiment.

[0072] like Figure 1 , Figure 3 and Figure 6 As shown, to facilitate rapid processing of the positive temperature coefficient (PTC) thermistor layer 3, in one embodiment, the PTC thermistor layer 3 includes a first coating layer 33 disposed on the first surface 11 and a second coating layer 34 disposed on the second surface 12, wherein the width of the first coating layer 33 is equal to the width of the second coating layer 34. During production, the coating device for processing the PTC thermistor layer 3 is fixed to ensure uniform unwinding and winding speed of the substrate layer 1, thereby enabling rapid and efficient processing of the first coating layer 33 and the second coating layer 34 with equal widths. This configuration improves the production efficiency of the current collector and facilitates processing.

[0073] Specifically, such as Figure 1 and Figure 3 As shown, in one embodiment, the first coating 33 and the second coating 34 are provided in a one-to-one correspondence. This facilitates manufacturing and processing, and at the same time, helps to ensure the uniformity of mechanical strength of various parts of the current collector.

[0074] Or, such as Figure 6 As shown, in another embodiment, along the first direction, the projected outer contour of the first coating 33 is at least partially offset along a third direction from the projected outer contour of the second coating 34. That is, the first coating 33 and the second coating 34 can be offset along a third direction to increase the effective area of ​​the positive temperature coefficient thermistor layer 3 on the substrate layer 1, and can quickly prevent the battery temperature from continuing to rise after the current collector generates an overcurrent phenomenon.

[0075] Alternatively, the above embodiments can be implemented simultaneously, with some of the first coating 33 and some of the second coating 34 being provided in a one-to-one correspondence, and some of the first coating 33 and some of the second coating 34 being distributed alternately. This embodiment is not limited to a single one.

[0076] In one embodiment, the maximum spacing H between two adjacent positive temperature coefficient thermistor layers 3 on the first surface 11 or the second surface 12 of the substrate layer 1 is between 10 cm and 1000 cm. When the positive temperature coefficient thermistor layer 3 is arranged as a linear coating structure, the maximum spacing H between two adjacent positive temperature coefficient thermistor layers 3 is the distance between the center lines of two adjacent linear coating structures. When the positive temperature coefficient thermistor layer 3 is arranged as a curved coating structure, the maximum spacing H between two adjacent positive temperature coefficient thermistor layers 3 is the distance between the center lines of two adjacent curved coating structures in the cross section along the third direction. Specifically, the maximum spacing H between two adjacent positive temperature coefficient thermistor layers 3 can be set to one of 10 cm, 20 cm, 100 cm, 200 cm, 300 cm, 400 cm, 500 cm, 600 cm, 700 cm, 800 cm, 900 cm, 1000 cm, etc., to ensure that the positive temperature coefficient thermistor layer 3 can uniformly block the current and uniformly prevent the temperature from continuously rising, and to ensure that the heat distribution of the current collector is uniform. If the maximum spacing H between two adjacent positive temperature coefficient thermistor layers 3 is less than 10 cm, the contact area of the conductive layer 2 and the substrate layer 1 is too small, which affects the interfacial bonding force between the conductive layer 2 and the substrate layer 1. If the maximum spacing H between two adjacent positive temperature coefficient thermistor layers 3 is greater than 1000 cm, when the temperature in the region between two adjacent positive temperature coefficient thermistor layers 3 is too high, the internal resistance of the positive temperature coefficient thermistor layer 3 cannot be raised in time to block the current, which can easily cause the current collector to be pierced due to overcurrent, and there is a great safety hazard.

[0077] In one embodiment, the maximum width D of the positive temperature coefficient thermistor layer 3 is between 0.1 pm and 100 mm. If the cross section of the positive temperature coefficient thermistor layer 3 along the third direction is arranged as a rectangular coating structure, the maximum width D of the positive temperature coefficient thermistor layer 3 is the length of the rectangular coating structure along the third direction. If the cross section of the positive temperature coefficient thermistor layer 3 along the third direction is arranged as a circular coating structure, the maximum width D of the positive temperature coefficient thermistor layer 3 is the diameter length of the circle. If the cross section of the positive temperature coefficient thermistor layer along the third direction is arranged as an irregularly shaped coating structure, the maximum width D of the positive temperature coefficient thermistor layer 3 is the distance between the opposite two side vertices of the positive temperature coefficient thermistor layer along the third direction, which is not limited in this embodiment. The maximum width D of the positive temperature coefficient thermistor layer 3 can be set to one of 0.1 pm, 100 pm, 500 pm, 1 mm, 5 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, etc. When the current collector overflows, the positive temperature coefficient thermistor layer 3 can effectively block the current from continuing to conduct along the third direction and prevent the temperature of the current collector from continuously rising.

[0078] If the maximum width D of the positive temperature coefficient thermistor layer 3 is less than 0.1 μm, the width of the positive temperature coefficient thermistor layer 3 is too small to generate sufficient resistance to block the current, and the current collector temperature is prone to continue to rise when the current is too large, which is prone to safety problems; if the maximum width D of the positive temperature coefficient thermistor layer 3 is greater than 100 mm, it will affect the contact area of the conductive layer 2 and the substrate layer 1, which is not conducive to the stable combination of the conductive layer 2 on the substrate layer 1.

[0079] In one embodiment, the current collector further comprises a bonding force enhancement layer 4, which is arranged on the surface of the substrate layer 1 and located between two adjacent positive temperature coefficient thermistor layers 3, and the conductive layer 2 is arranged on the surface of the bonding force enhancement layer 4 and the positive temperature coefficient thermistor layer 3 away from the substrate layer 1. The bonding force enhancement layer 4 can improve the adhesion of the conductive layer 2 to the substrate layer 1, thereby further ensuring that the conductive layer 2 is not prone to detachment or sporadic detachment from the substrate layer 1, improving the structural stability of the current collector and the product quality. The bonding force enhancement layer 4 can form an extremely thin chemical bond layer on the surface of the substrate layer 1, which can not only fill the small defects on the surface of the substrate layer 1, but also increase the surface roughness, so that the contact between the conductive layer 2 and the substrate layer 1 is more closely, so that the bonding surface has a larger contact area and a stronger interaction force, which can significantly enhance the bonding strength between the substrate layer 1 and the conductive layer 2, and at the same time ensure that the plurality of positive temperature coefficient thermistor layers 3 are stably positioned on the surface of the substrate layer 1 without relative displacement.

[0080] Among them, the bonding force enhancement layer 4 can be set as a metal plating layer, for example, the bonding force enhancement layer 4 is set as a nickel layer or a chromium layer; or, the bonding force enhancement layer 4 can also be set as a non-metal plating layer, for example, the bonding force enhancement layer 4 is set as a graphene layer, a silicon carbide layer, a silicon nitride layer or an aluminum oxide layer. It can be understood that the material of the bonding force enhancement layer 4 includes but is not limited to this, and the specific material is subject to the actual situation.

[0081] Among them, as Figure 7As shown, along the first direction, the thickness d1 of the adhesion enhancement layer 4 is between 10 nm and 100 nm. For example, the thickness d1 of the adhesion enhancement layer 4 can be set to one of 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm. The adhesion enhancement layer 4 can provide sufficient adhesion strength to ensure a tight bond between the layers of the current collector, preventing interlayer separation or detachment caused by vibration, impact, or other factors during battery use, thus ensuring the stability and reliability of the current collector. The adhesion enhancement layer 4 can also provide the current collector with a certain degree of flexibility and mechanical strength, further ensuring the stability and safety of the current collector. If the thickness d1 of the adhesion enhancement layer 4 is less than 10 nm, it may result in poor adhesion strength, affecting the stability of the current collector. If the thickness d1 of the adhesion enhancement layer 4 is greater than 100 nm, it may affect the connection between the conductive layer 2 and the substrate layer 1, thus affecting the electrical conductivity of the current collector.

[0082] In one embodiment, the current collector further includes an anti-oxidation layer 5, which is disposed on the surface of the conductive layer 2 away from the substrate layer 1. The anti-oxidation layer 5 effectively prevents the conductive layer 2 from undergoing oxidation under the influence of the external environment, preventing oxidation of the conductive layer 2 from affecting its conductivity. Therefore, the anti-oxidation layer 5 can greatly extend the service life of the current collector, ensuring that it maintains stable conductivity even during long-term use.

[0083] Among them, such as Figure 7 As shown, along the first direction, the thickness d2 of the anti-oxidation layer 5 is between 10 nm and 100 nm. For example, the thickness d2 of the anti-oxidation layer 5 can be set to one of 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm. This helps to protect the conductive layer 2 from the influence of the external environment, prevents the conductive layer 2 from oxidation, helps to improve the overall performance of the current collector, and also helps to improve the structural strength of the current collector. If the thickness d2 of the anti-oxidation layer 5 is less than 10 nm, the thin anti-oxidation layer 5 may be more easily penetrated or damaged, causing the conductive layer 2 to be oxidized, which in turn affects the performance and lifespan of the current collector, and the processing difficulty is also higher. If the thickness d2 of the anti-oxidation layer 5 is greater than 100 nm, the anti-oxidation layer 5 is too thick, which will increase the resistance of the current collector and lead to a decrease in conductivity.

[0084] The anti-oxidation layer 5 can be a dense metal layer, such as a nickel layer, chromium layer, nickel alloy layer, or chromium alloy layer. Alternatively, the anti-oxidation layer 5 can be a non-metallic layer, such as a graphene layer, alumina layer, silicon nitride layer, or silicon carbide layer. Specifically, the material and thickness parameters of the anti-oxidation layer 5 can be optimized according to the specific application scenario.

[0085] In one embodiment, the substrate layer 1 comprises at least one of a polyethylene layer, a polypropylene layer, a polyimide layer, a glass fiber layer, a cotton layer, a hemp layer, an o-phenylphenol layer, a polyimide layer, a polyethylene terephthalate layer, a chlorinated polypropylene resin layer, a polyvinyl chloride layer, or an Ajinomoto build-up film layer. Preferably, the material of the substrate layer 1 is selected from an Ajinomoto build-up film (ABF film), which is a highly durable and rigid film that can effectively resist expansion and contraction under temperature changes, ensuring the stability of the current collector under various environments, thereby improving the reliability and safety of the current collector and prolonging the service life of the current collector. In addition, the surface of the ABF film can be subjected to laser processing and direct copper plating, ensuring that the current collector can be processed and prepared in a “one-step method”, thereby simplifying the production process and improving production efficiency.

[0086] wherein, as shown in Figure 7 The thickness d3 of the substrate layer 1 is between 0.5 μm and 8 μm in the first direction. For example, the thickness d3 of the substrate layer 1 can be set to one of 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, etc., ensuring that the substrate layer 1 has sufficient strength and rigidity to resist current impact and temperature changes during battery charging and discharging, ensuring the stability and reliability of the current collector, while achieving lightweight of the battery. If the thickness d3 of the substrate layer 1 is less than 0.5 μm, the substrate layer 1 is too thin, and the mechanical strength of the substrate layer 1 is low, which causes the current collector to be unable to withstand the impact of the current and the temperature changes inside the battery, which may cause the current collector to break, be punctured, etc., affecting the normal use of the current collector; if the thickness d3 of the substrate layer 1 is greater than 8 μm, the substrate layer 1 is too thick, which directly causes the weight of the current collector and even the entire battery to increase, affecting its portability. Moreover, the excessive thickness of the substrate layer 1 also leads to a decrease in the energy density of the battery, resulting in a decrease in the energy storage capacity of the battery.

[0087] Preferably, the thickness d3 of the substrate layer 1 is set to 0.5 μm to 1 μm, and specifically, the thickness d3 of the substrate layer 1 can be set to one of 0.5 μm, 0.6 μm, 0.7 μm, 0.75 μm, 0.8 μm, 0.9 μm, 1 μm, etc., ensuring the structural strength of the substrate layer 1, while taking into account the stability and reliability of the current collector.

[0088] When the substrate layer 1 is set as an ABF film layer (ABF, i.e., Ajinomoto reinforced film, also known as Ajinomoto stacked film), the substrate layer 1 can resist expansion and contraction during temperature changes, giving the current collector stronger tensile strength. It also allows for a larger window of variation in tension and pressure during various manufacturing processes, enabling the application of higher pressure to the current collector in the preparation stage to achieve greater compaction density, thus improving process manufacturing capabilities. Given these advantages of the ABF film layer, the surface of the substrate layer 1 can be laser-processed and directly copper-plated, allowing for a "one-step" manufacturing process for the current collector, improving its manufacturing efficiency.

[0089] Therefore, in conjunction with the above embodiments, when the material of the substrate layer 1 is Ajinomoto deposited film and the thickness d3 of the substrate layer 1 is set to 0.5μm to 1μm, compared with the existing current collector structure, the weight of the current collector using the substrate layer 1 can be reduced by 50% and the thickness of the current collector can be reduced by 30% compared with the existing current collector structure, thus significantly improving the battery energy density.

[0090] Among them, such as Figure 7 As shown, along the first direction, the thickness d4 of the conductive layer 2 is between 100nm and 1000nm. For example, the thickness d4 of the conductive layer 2 can be set to one of 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, or 1000nm. The conductive layer 2 can form a continuous and stable conductive channel, ensuring that the current can flow smoothly, guaranteeing good electrical conductivity of the current collector, and ensuring good interfacial bonding between the substrate layer 1 and the conductive layer 2, making it difficult for the conductive layer 2 to detach from the substrate layer 1. If the thickness d4 of the conductive layer 2 is less than 100nm, the conductive layer 2 becomes too thin and easily detaches from the substrate layer 1 under the action of a large external adhesive force. Moreover, the current carrying capacity of an excessively thin conductive layer 2 is poor, making it prone to burn-out and damage. If the thickness d4 of the conductive layer 2 is greater than 1000nm, it will increase the overall weight and volume of the current collector, making it inconvenient for installation and use.

[0091] In summary, by incorporating a positive temperature coefficient thermistor layer 3, the resistance and mechanical strength of the current collector can be increased. Furthermore, when the current collector is punctured, the resistance at the puncture point can be increased, reducing the current during a short circuit and decreasing the heat generated during the short circuit, thereby reducing the danger caused by current collector puncture.

[0092] Furthermore, this application can reduce the thickness of the current collector, thereby reducing its weight inside the battery and indirectly increasing the battery's energy density. Simultaneously, it reduces the sheet resistance of the current collector surface, lowers the risk of battery combustion, and improves the mechanical strength of the current collector, which is beneficial for enhancing battery performance.

[0093] The application also provides a battery, which comprises the current collector according to any one of the above embodiments.

[0094] The battery comprises one of a ternary lithium battery, a lithium iron phosphate battery, etc. The working temperature range of the ternary lithium battery is generally between -20°C and 60°C, and the performance of the ternary lithium battery is relatively stable within this temperature range. However, when the temperature drops below 0°C, the performance of the ternary lithium battery begins to gradually decrease, and the discharge capacity and overall service life are affected and decreased. Therefore, in order to maintain the ternary lithium battery in a better performance and longer service life, the use temperature of the ternary lithium battery is preferably controlled between 0°C and 40°C. Therefore, based on the use temperature range of the ternary lithium battery, the Curie temperature of the positive temperature coefficient thermistor layer 3 in the ternary lithium battery can be controlled between 80°C and 100°C, such as 80°C, 84°C, 88°C, 90°C, 94°C, 96°C, 100°C, etc.

[0095] Since the thermal runaway temperature of the lithium iron phosphate battery is generally above 500°C, the Curie temperature of the positive temperature coefficient thermistor layer 3 in the lithium iron phosphate battery can not be particularly limited, and can be below 400°C, for example, 100°C, 200°C, 300°C, 350°C, etc.

[0096] The application also provides an electrical equipment comprising a battery, and the battery comprises the battery according to the above embodiments. Therefore, the electrical equipment and the battery comprise all the technical effects of the above current collector. Since the technical effects of the current collector have been described in detail above, they will not be described here.

[0097] For ease of description, spatial relative terms such as "over", "above", "upper surface", "upper", etc. can be used herein to describe the spatial relationship of one device or feature to other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the device described in the drawings. For example, if the device in the drawing is inverted, the device described as "above" or "over" other devices or structures will be positioned "below" or "under" the other devices or structures. Thus, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0098] In addition, it should be noted that the use of "first", "second", and the like words to qualify elements is merely intended to distinguish the respective elements from one another, and does not have a special meaning unless otherwise stated. Therefore, these words should not be interpreted as limiting the scope of protection of the present application.

[0099] The preferred embodiments of the present application have been described above with the help of drawings. However, for those skilled in the art, many changes and modifications can be made without departing from the scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application.

Claims

1. A current collector characterized by comprising: Comprising: a substrate layer (1) comprising a first surface (11) and a second surface (12) along a first direction; a conductive layer (2) disposed on at least one of the first surface (11) and the second surface (12), the conductive layer (2) comprising a first end (21) and a second end (22) along a second direction; a positive temperature coefficient thermistor layer (3) disposed on at least one side of the conductive layer (2) along the first direction and in contact with the conductive layer (2), the length of the positive temperature coefficient thermistor layer (3) extending from the first end (21) to the second end (22), and the width of the positive temperature coefficient thermistor layer (3) along a third direction being less than the width of the conductive layer (2) along the third direction.

2. The current collector of claim 1, wherein The conductive layer (2) comprises a first edge (23) and a second edge (24) along the third direction, and a predetermined gap (6) is provided between the positive temperature coefficient thermistor layer (3) and the first edge (23) and the second edge (24), respectively.

3. The current collector of claim 2, wherein The positive temperature coefficient thermistor layer (3) comprises a plurality of positive temperature coefficient thermistor layers (3) disposed on the surface of the substrate layer (1) along the third direction, and the conductive layer (2) is disposed on the surface of the substrate layer (1) and located between two adjacent positive temperature coefficient thermistor layers (3); and / or, the conductive layer (2) is disposed on the substrate layer (1) and covers the surface of the positive temperature coefficient thermistor layer (3) away from the substrate layer (1).

4. The current collector of claim 1, wherein The positive temperature coefficient thermistor layer (3) comprises at least one of a straight line type coating structure and a curved line type coating structure.

5. The current collector according to any one of claims 1 to 4, wherein The positive temperature coefficient thermistor layer (3) comprises: a main body section (31) having a length extending from the first end (21) to the second end (22); an extension section (32) having a length less than the length of the main body section (31) along the second direction, the extension section (32) comprising a plurality of extension sections (32) disposed on at least one side of the main body section (31) along the third direction.

6. The current collector of claim 5, wherein The main body section (31) comprises a first side (311) and a second side (312) along the third direction, the first side (311) and the second side (312) are both provided with the extension section (32), and the extension section (32) located on the first side (311) is correspondingly disposed with the extension section (32) located on the second side (312); and / or, The projection outer contour of the extension section (32) located on the first side (311) is at least partially misaligned with the projection outer contour of the extension section (32) located on the second side (312) along the second direction.

7. The current collector according to any one of claims 1 to 4, 6, wherein The positive temperature coefficient thermistor layer (3) comprises: a first coating layer (33) disposed on the first surface (11); a second coating (34) disposed on the second surface (12), the width of the first coating (33) being equal to the width of the second coating (34).

8. The current collector of claim 7, wherein the first coating (33) and the second coating (34) are disposed one by one; and / or, in the first direction, the projected outer contour of the first coating (33) is at least partially misaligned with the projected outer contour of the second coating (34) in the third direction.

9. The current collector of any one of claims 3-4, 6, wherein, on the first surface (11) or the second surface (12) of the substrate layer (1), the maximum distance between two adjacent PTCR layers (3) is between 10 cm and 1000 cm; and / or, the maximum width of the PTCR layer (3) is between 0.1 μm and 100 mm.

10. The current collector of any one of claims 1 to 4, 6, 8, wherein Further comprising: a cohesion enhancement layer (4) disposed on the surface of the substrate layer (1) between two adjacent PTCR layers (3), the conductive layer (2) being disposed on the surface of the cohesion enhancement layer (4) and the PTCR layer (3) away from the surface of the substrate layer (1); and / or, an oxidation prevention layer (5) disposed on the surface of the conductive layer (2) away from the surface of the substrate layer (1).

11. The current collector of claim 10, wherein in the first direction, the thickness of the cohesion enhancement layer (4) is between 10 nm and 100 nm; and / or, in the first direction, the thickness of the oxidation prevention layer (5) is between 10 nm and 100 nm.

12. The current collector of any one of claims 1 to 4, 6, 8, wherein, in the first direction, the thickness of the substrate layer (1) is between 0.5 μm and 8 μm; and / or, in the first direction, the thickness of the conductive layer (2) is between 100 nm and 1000 nm.

13. A battery, characterized by A current collector according to any one of claims 1 to 12.

14. An electrical device, characterized by A battery according to claim 13.

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