A lithium-ion battery current collector, a lithium-ion battery electrode, and a lithium-ion battery

Abstract

This invention discloses a lithium-ion battery current collector, comprising a mesh frame and a metal thin film; the mesh frame is made of a positive temperature coefficient material; several metal thin films are disposed in several mesh holes of the mesh frame, and the metal thin films in adjacent mesh holes are independent of each other; the thickness of the mesh frame is not less than that of the metal thin films. This invention also discloses a lithium-ion battery electrode and a lithium-ion battery incorporating the above-mentioned current collector. The current collector of this invention can significantly improve the safety performance of the battery, and also has the advantages of simple structure and low cost, which is conducive to large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology, and relates to a lithium-ion battery current collector, a lithium-ion battery electrode, and a lithium-ion battery. Background Technology

[0002] With the large-scale application of lithium-ion batteries, their safety has received widespread attention, especially for automotive power batteries, military batteries, and aircraft batteries. When faced with extreme conditions such as internal short circuits, impacts, and especially needle penetration, serious safety accidents such as fires and explosions may occur.

[0003] In existing technologies, the safety performance of lithium-ion batteries can be improved by modifying the structure of the current collector. The main methods include coating a layer of carbon fiber with a PTC effect onto the current collector metal foil using electrospinning. This allows the lithium battery to generate high resistance at high temperatures, suppressing heat generation. While this method improves safety, it is complex and difficult to mass-produce. It also increases the thickness of the current collector. Furthermore, this technology requires annealing at 800°C, limiting its application to negative electrode current collectors and preventing its use in positive electrode applications. In extreme tests such as needle penetration, the positive electrode current collector and positive electrode active material come into contact with the negative electrode current collector and negative electrode active material through a steel needle, leading to extremely high current discharge. This technology only restricts the contact of the negative electrode current collector but cannot restrict the contact of the inherently conductive negative electrode active material, thus offering limited improvement in safety during needle penetration tests. The current collector consists of a conductive thin film substrate and a metallized film layer. The metallized film layer adopts a patterned design, connecting all conductive islands through conductive bridges. It can melt and completely isolate the conductive islands when the current is too high, cutting off the connection with adjacent conductive islands. Since the conductive thin film substrate only has the conductivity of a semiconductor, it can play a safety protection role. This technology uses a lot of methods such as evaporation and controlled sputtering, which are expensive, energy-intensive, and have low production efficiency, making it difficult to mass-produce. At the same time, the polymer conductive thin film substrate is a semiconductor, while the metallized film layer has a patterned design. A large amount of active material is directly in contact with the conductive substrate of the semiconductor, which affects the current conduction of the current collector, resulting in high battery internal resistance and affecting the high current discharge capability. Summary of the Invention

[0004] The purpose of this invention is to overcome the aforementioned shortcomings and provide a lithium-ion battery current collector, a lithium-ion battery electrode, and a lithium-ion battery. This invention solves the technical problems of high cost and complex manufacturing processes associated with existing current collectors used to improve the safety performance of lithium-ion batteries. The current collector of this invention can significantly improve battery safety performance. It also has the advantages of simple structure and low cost, which facilitates large-scale production.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] A lithium-ion battery current collector includes a grid frame and a metal thin film;

[0007] The materials used in the mesh frame include materials with a positive temperature coefficient;

[0008] Several metal films are placed in several grid holes of a grid frame, and the metal films in adjacent grid holes are independent of each other;

[0009] The thickness of the mesh frame is greater than or equal to the thickness of the metal film.

[0010] Furthermore, the materials used in the mesh frame also include conductive materials;

[0011] The positive temperature coefficient material is one or more of polymer PTC thermistor materials or ceramic PTC thermistor materials;

[0012] The conductive material is one or more of carbon, Al, Cu, or conductive polymers.

[0013] Furthermore, the thickness of the metal thin film is less than or equal to the thickness of the grid frame and less than or equal to the thickness of the electrode sheet made of lithium-ion battery current collector.

[0014] Furthermore, the thickness of the mesh frame is equal to the thickness of the electrode sheet made of lithium-ion battery current collector.

[0015] Furthermore, the materials used for the metal thin film are Al or Cu;

[0016] When the lithium-ion battery current collector is used as the negative electrode current collector, the material used for the metal thin film is Cu, and the thickness of the metal thin film is 4-10 μm.

[0017] When the current collector of a lithium-ion battery is used as the positive electrode current collector, the material used for the metal thin film is Al, and the thickness of the metal thin film is 8-25 μm.

[0018] Furthermore, the cross-section of the grid frame is rectangular, and the width of the grid frame is 0.1mm-2mm; the size of the grid holes is 0.1-10cm. 2 ;

[0019] The number of mesh holes in a single current collector's mesh frame is determined by the following formula:

[0020] Where n≥4, m is the battery mass, and R is the internal resistance of the battery using conventional current collectors. In batteries using conventional current collectors, all aspects are the same except for the material and structure of the current collector.

[0021] The above-mentioned method for preparing a lithium-ion battery current collector includes:

[0022] S1 uses laser printing to form the powder material used for the mesh frame, thus obtaining the mesh frame;

[0023] S2 presses the mesh frame to make its surface flat and to make the mesh frame thickness reach the preset thickness.

[0024] S3 wraps the entire metal film over the grid frame and connects the metal film to the grid frame by laser welding, electroplating or rolling.

[0025] S4 roughens the surface of the metal thin film through laser or ultrasonic treatment;

[0026] S5 cuts the entire metal film into several metal films located in the grid holes, so that the metal films in adjacent grid holes are independent of each other;

[0027] S6 involves pressing and cutting the product obtained in step S5.

[0028] A lithium-ion battery electrode, comprising the aforementioned lithium-ion battery current collector;

[0029] The current collector of a lithium-ion battery is coated with electrode active material, conductive agent and binder.

[0030] The above-mentioned method for preparing lithium-ion battery electrodes includes:

[0031] S1 mixes the electrode active material powder, conductive agent powder and binder powder evenly to obtain a mixed powder;

[0032] S2 involves heating and pre-pressing the mixed powder at a temperature of 60–150°C and a pre-pressing thickness of 40–200 μm to obtain an electrode material layer.

[0033] S3. The electrode material layer is placed into the mold; the mold has a groove, and a tab platform is provided on one side of the groove, and the electrode material layer is placed in the groove;

[0034] S4 places the current collector into the mold, wherein the tab of the current collector is located on the tab platform, and the other part of the current collector is located above the electrode material layer;

[0035] S5 covers the current collector with another electrode material layer obtained in step S2, forming an electrode material layer-current collector-electrode material layer structure;

[0036] S6 hot-presses the electrode material layer-current collector-electrode material layer structure at a heating temperature of 60-150℃. The thickness of the compacted electrode is 60-400µm. The adhesive in the electrode material layer is bonded to the current collector under heating conditions.

[0037] Preferably, the pre-compression thickness is 1.1 to 1.3 times the thickness of the compacted electrode.

[0038] A lithium-ion battery, wherein the positive or negative electrode of the lithium-ion battery is the aforementioned lithium-ion battery electrode.

[0039] Alternatively, both the positive and negative electrodes of the lithium-ion battery may be one of the aforementioned lithium-ion battery electrodes.

[0040] Compared with the prior art, the present invention has at least one of the following advantages:

[0041] (1) This invention creatively proposes a lithium-ion battery current collector, which uses a grid frame with a positive temperature coefficient to achieve the technical effect of limiting the battery discharge output when the internal temperature of the battery rises, greatly improving the safety performance of the battery. At the same time, it can realize the reversible protection of the battery in the case of external short circuit, extreme high current, high temperature, etc., and can still resume normal operation when the battery temperature returns to normal.

[0042] (2) The lithium-ion battery of the present invention adopts a dry electrode preparation process, which does not require slurry preparation, coating and other processes, and does not use toxic solvents such as NMP. According to the set electrode size, it can be mass-produced with relevant equipment. It has the advantages of simple process, environmental protection and low cost, which is conducive to large-scale production.

[0043] (3) The present invention solves the problem of weak adhesion of dry electrode material layers by roughening the surface of the current collector;

[0044] (4) The present invention uses laser printing to prepare PTC mesh frames, which has the advantages of high efficiency, low cost and simple process. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the lithium-ion battery current collector of the present invention;

[0046] Figure 2 The mold used to prepare the lithium-ion battery electrode in this invention;

[0047] Figure 3 This is a schematic diagram of the lithium-ion battery electrode of the present invention;

[0048] Figure 4 This is a schematic diagram of the lithium-ion battery assembly of the present invention. Detailed Implementation

[0049] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.

[0050] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0051] This invention provides a lithium-ion battery current collector, a lithium-ion battery electrode, and a lithium-ion battery, which have the advantages of high safety and simple structure. When the battery temperature rises abnormally due to extreme conditions such as short circuit, puncture, or overcurrent discharge, the resistance of the PTC material in the current collector increases rapidly, limiting the current output, thereby protecting the battery from fire and explosion.

[0052] A lithium-ion battery current collector includes a positive temperature coefficient grid frame and a metal thin film. The metal thin film fills the pores of the grid frame. The thickness of the grid frame is not less than the thickness of the metal thin film and not more than the thickness of the compacted electrode. The thickness of the metal thin film is 4-25 μm. The grid frame thickness being not less than the metal thin film thickness serves two purposes: first, to prevent contact between the metal thin films in adjacent grid pores; second, if the grid frame thickness is equal to the metal thin film thickness, the current collector surface can be smooth; if the thickness is greater than the metal thin film thickness, the grid frame will be embedded in the electrode material, further improving safety; if the thickness is equal to the total thickness of the compacted electrode (including the metal thin film), the grid frame can separate the electrode active material into independent regions, maximizing battery safety.

[0053] Grid frame width (i.e.) Figure 1 The dimension indicated by the middle arrow is 0.1mm-2mm. The narrower the width, the better the effect and the least impact on internal resistance, but the manufacturing process is slightly more difficult. The wider the width, the more it will increase the internal resistance to a certain extent, but the manufacturing process is less difficult.

[0054] The mesh framework divides the active material layer of the current collector or electrode into several regions, with mesh pore areas ranging from 0.1 to 10 cm². 2 Preferably, the distribution density of the mesh frame (the number of thin metal films filling a single current collector) is... Where n≥4, m is the battery mass in kg, and R is the internal resistance of the battery using a conventional current collector in Ω. In batteries using conventional current collectors, all aspects are the same except for the material and structure of the current collector, that is, the current collector thickness, battery manufacturing process, etc. are the same. The conventional current collector is a positive electrode aluminum foil and a negative electrode copper foil. The thickness of the positive electrode aluminum foil and the negative electrode copper foil is the same as the thickness of the metal film of the present invention.

[0055] The positive temperature coefficient grid framework is composed of polymer PTC thermistor material and / or ceramic PTC thermistor, and may also contain conductive material, which can adjust the conductivity of the positive temperature coefficient PTC material.

[0056] The ceramic PTC thermistor is composed of BaTiO3 doped with Ta, Sn, and Bi, with Ta content of 0-0.5%, Sn content of 0-1.0%, and Bi content of 0-0.5%.

[0057] Polymer PTC is composed of organic polymers and carbon materials. The organic polymers include, but are not limited to, PP, PE, PVC and PET, and the carbon materials include, but are not limited to, carbon black, carbon fiber and graphene.

[0058] The metal thin film is made of Al or Cu.

[0059] A lithium battery electrode, Figure 3 As shown, it includes the aforementioned current collector, as well as electrode active material, conductive agent and binder coated on the current collector.

[0060] A lithium battery includes the aforementioned lithium battery electrodes. For example... Figure 4 As shown, the lithium battery includes a positive electrode, a negative electrode, and a separator 30. The positive electrode includes a positive current collector 10 and a positive active material 11 coated on the positive current collector 10. The negative electrode includes a negative current collector 20 and a negative active material 21 coated on the negative current collector 20.

[0061] like Figure 1 As shown, the current collector of this invention comprises a grid frame 2 made of a positive temperature coefficient material and a metal thin film 1. When used as a negative electrode current collector, the metal thin film 1 is a copper foil with a thickness of 4–10 μm; when used as a positive electrode current collector (or lithium titanate negative electrode), the metal thin film 1 is an aluminum foil with a thickness of 8–25 μm. The metal foil is separated by the positive temperature coefficient grid frame. The positive temperature coefficient grid frame has very low resistance at low to medium temperatures (≤80°C), the grid frame width is 0.1 mm–2 mm, and the area of ​​the grid holes is 0.1–10 cm². 2 The positive temperature coefficient (PTC) grid framework is composed of polymer PTC thermistor material and / or ceramic PTC thermistors. The ceramic PTC thermistors are composed of BaTiO3 doped with Ta, Sn, Bi, etc., with Ta content of 0–0.5%, Sn content of 0–1.0%, and Bi content of 0–0.5%. Electrode sheets are formed by coating this current collector with active material, conductive agent, and binder. The positive and negative electrode sheets and separator are then assembled into an electrode assembly. Finally, the electrode assembly is placed in the battery casing, and the battery is completed after liquid injection and formation. The use of the composite current collector has minimal impact on the normal operation of the battery. Under extreme conditions such as discharge exceeding the design current, external short circuit, internal short circuit, high temperature, and needle penetration, when the internal temperature rises to a certain level (60℃-200℃), the resistance of the PTC grid framework increases exponentially, thereby limiting the battery's discharge output and providing safety protection.

[0062] Example 1

[0063] This embodiment provides a positive current collector, a positive electrode sheet, and a lithium-ion battery, including a positive temperature coefficient grid frame and a metal thin film. The metal thin film fills the holes in the grid frame, and the thickness of the grid frame is equal to the thickness of the metal thin film. The metal thin film has a thickness of 15 μm and is made of Al.

[0064] Current collector preparation:

[0065] S1 uses positive temperature coefficient powder material and uses laser printing to prepare PTC mesh frame according to the mesh frame design size. The mesh frame width is 0.5mm, the mesh frame is square, and the side length is 20mm.

[0066] S2 presses the prepared mesh frame to make its surface flat and its thickness consistent with the current collector design thickness of 15um;

[0067] S3 selects 15um aluminum foil, covers the grid frame, and connects the metal film to the grid frame by laser welding;

[0068] S4 roughens the surface of the current collector through laser processing;

[0069] S5 removes the residual metal film on the grid frame, then presses the current collector and cuts it according to the electrode design size. The current collector size is 60mm*120mm, and the grid frame divides the current collector into 18 regions.

[0070] Electrode preparation:

[0071] S1 mixes the electrode active material NCM powder, conductive agent SP powder, and binder PVDF powder evenly.

[0072] S2 involves pre-compressing the mixed powder at a heating temperature of 120℃, with a pre-compressed thickness of 80µm and a surface density of 20±0.3mg / cm³. 2 To form an electrode material layer;

[0073] S3 places the prepared electrode material layer into a pre-designed groove in the mold. The groove shape is consistent with the current collector, with a depth of 1 mm. The groove has a heating function, and a tab platform is reserved on one side of the groove. The platform height (i.e., the height from the bottom of the groove) is 60 μm. The electrode material layer is located in the remaining part of the groove outside the tab platform. The specific structure of the mold is as follows: Figure 2 As shown;

[0074] S4 Place the cut current collector on the electrode material layer, and then cover the current collector with another electrode material layer to form an electrode material layer-current collector-electrode material layer structure;

[0075] S5 uses a hot pressing device to compact the electrode material layer and the current collector. The heating temperature is 120℃, and the total thickness of the electrode after compaction is 135um, thus forming a positive electrode sheet.

[0076] The positive temperature coefficient grid-like frame is composed of ceramic PTC thermistors, which are BaTiO3 doped with Ta, Sn, and Bi, with a Ta content (mass content) of 0.3%, a Sn content of 1.0%, and a Bi content of 0.3%.

[0077] A negative electrode sheet was prepared using 8µm copper foil as the negative electrode current collector, artificial graphite C as the negative electrode active material, and CMS+SBR as the binder, according to conventional methods.

[0078] Battery fabrication:

[0079] A 5Ah soft-pack battery is manufactured by stacking positive and negative electrode sheets with a separator.

[0080] The battery is injected with electrolyte and formed.

[0081] Example 2

[0082] This embodiment provides a positive current collector, a positive electrode sheet, and a lithium-ion battery, which are the same as the rest of the embodiment 1, except that the mesh frame is 135um thick and the PTC mesh frame divides the positive electrode active material into several independent regions.

[0083] Example 3

[0084] This embodiment provides a negative electrode current collector, a negative electrode sheet, and a lithium-ion battery. The current collector preparation is the same as the rest of the embodiment 1, except that the mesh frame and the metal film have the same thickness of 8 μm and are made of Cu.

[0085] Negative electrode preparation:

[0086] S1 mixes the electrode active material artificial graphite C powder and the binder PVDF powder evenly.

[0087] S2 involves heating and pre-compressing the mixed powder to a thickness of 80 μm and an areal density of 10 ± 0.3 mg / cm³. 2 To form an electrode material layer;

[0088] S3 Place the prepared electrode material layer into a preset groove. The groove shape is consistent with the current collector and the depth is 1mm. The groove has a heating function. A tab platform with a height of 60um is reserved on one side of the groove.

[0089] S4 places the cut current collector on the electrode material layer, and then covers the electrode material layer with another electrode material layer to form an electrode material layer-current collector-electrode material layer structure.

[0090] S5 uses a hot pressing device to compact the electrode material layer and the current collector. The total thickness of the compacted electrode is 128 μm, which is used to make a negative electrode sheet.

[0091] A positive electrode sheet was prepared using 15µm aluminum foil as the current collector, NCM as the positive electrode active material, SP as the conductive agent, and PVDF as the binder, following conventional methods.

[0092] Battery fabrication:

[0093] A 5Ah soft-pack battery is manufactured by stacking positive and negative electrode sheets with a separator.

[0094] The battery is injected with electrolyte and formed.

[0095] Example 4

[0096] This embodiment provides a negative electrode current collector, a negative electrode sheet, and a lithium-ion battery, which are the same as the rest of the embodiment 3, except that the mesh frame is 128 μm thick and the PTC mesh frame divides the negative electrode active material into several independent regions.

[0097] Example 5

[0098] The positive electrode sheet prepared in Example 1;

[0099] The negative electrode sheet prepared in Example 3.

[0100] A 5Ah soft-pack battery is manufactured by stacking positive and negative electrode sheets with a separator.

[0101] The battery is injected with electrolyte and formed.

[0102] Example 6

[0103] The positive electrode sheet prepared in Example 2;

[0104] The negative electrode sheet prepared in Example 4.

[0105] A 5Ah soft-pack battery is manufactured by stacking positive and negative electrode sheets with a separator.

[0106] The battery is injected with electrolyte and formed.

[0107] Comparative Example 1

[0108] A positive electrode sheet was prepared using 15µm aluminum foil as the positive electrode current collector, NCM as the positive electrode active material, SP as the conductive agent, and PVDF as the binder, according to conventional methods. A negative electrode sheet was prepared using 8µm copper foil as the negative electrode current collector, artificial graphite C as the negative electrode active material, and CMS+SBR as the binder, according to conventional methods.

[0109] A 5Ah soft-pack battery is manufactured by stacking positive and negative electrode sheets with a separator.

[0110] The battery is injected with electrolyte and formed.

[0111] Comparative Example 2

[0112] Preparation of negative electrode current collector:

[0113] A 2µm thick film was coated onto an 8µm thick copper current collector foil using electrospinning, and then subjected to high-temperature annealing under nitrogen to obtain carbon fiber with PTC effect, which was then used to make a composite negative electrode current collector.

[0114] Lithium-ion battery manufacturing:

[0115] A positive electrode sheet was prepared using 15µm aluminum foil, positive electrode active material NCM, conductive agent SP, and binder PVDF according to conventional methods. A negative electrode sheet was prepared using the prepared composite negative electrode current collector, negative electrode active material artificial graphite C, and binder CMS+SBR according to conventional methods.

[0116] A 5Ah soft-pack battery is manufactured by stacking positive and negative electrode sheets with a separator.

[0117] The battery is injected with electrolyte and formed.

[0118] The batteries prepared in the examples and comparative examples were subjected to different discharge rates (0.2C, 3C), external short circuit (5mΩ), and nail penetration tests. The test results are shown in Table 1.

[0119] Table 1. Test results of Examples 1-3 and Comparative Example 1

[0120] serial number 0.2C discharge capacity 3C discharge capacity External short circuit (5mΩ) Battery status after needle puncture Example 1 5.12Ah 4.88Ah No change in appearance Leakage but no fire or explosion Example 2 5.21Ah 4.65Ah No change in appearance No fire or explosion Example 3 5.13Ah 4.85Ah No change in appearance Fire started but did not explode Example 4 5.18Ah 4.72Ah No change in appearance No fire or explosion Example 5 5.10Ah 4.70Ah No change in appearance No fire or explosion Example 6 5.05Ah 4.48Ah No change in appearance No fire or explosion Comparative Example 1 5.15Ah 4.96Ah Battery bulging Fire and explosion Comparative Example 2 5.08Ah 3.54Ah No change in appearance Fire started but did not explode

[0121] The current collector of this invention has a relatively small impact on the rate performance of the battery. Because there is a significant difference in conductivity between the positive and negative electrode active materials—the negative electrode is much more conductive than the positive electrode—the composite current collector exhibits different effects on the positive and negative electrodes, performing better on the positive electrode.

[0122] Example 1: A composite current collector is used for the positive electrode, and the PTC grid frame has the same thickness as the current collector. This can isolate the positive electrode current collector during needle penetration. The current is mainly transmitted through the positive electrode active material and the steel needle to the negative electrode current collector and the negative electrode active material. The battery temperature rises, causing the battery to swell and leak, but it does not reach the ignition temperature.

[0123] Example 3 uses a composite current collector for the negative electrode, and the PTC grid frame has the same thickness as the current collector. This can isolate the negative electrode current collector during needle puncture. The current is mainly transmitted through the negative electrode active material and the steel needle to the positive electrode current collector and the positive electrode active material. Because the negative electrode active material has good conductivity, the needle puncture current is still large. The battery quickly leaks and catches fire but does not explode.

[0124] Example 2: The positive electrode uses a composite current collector, and the PTC grid frame is the same thickness as the electrode, which divides the positive electrode active material into several regions. This can isolate the positive electrode current collector and the positive electrode active material during needle penetration, greatly limiting the needle penetration current, and the battery did not catch fire or explode.

[0125] Example 4: The negative electrode uses a composite current collector, and the PTC grid frame is the same thickness as the electrode, which divides the negative electrode active material into several regions. This can isolate the negative electrode current collector and the negative electrode active material during needle puncture, greatly limiting the needle puncture current, and the battery did not catch fire or explode.

[0126] In Example 5, both the positive and negative electrodes use composite current collectors, and the PTC mesh frame has the same thickness as the current collector. This can isolate the negative electrode current collector and the positive electrode current collector during needle puncture. The current is mainly transmitted through the negative electrode active material and the steel needle and the positive electrode active material. The needle puncture current is further reduced compared to Example 1, and the battery did not catch fire or explode.

[0127] In Example 6, composite current collectors are used for both the positive and negative electrodes, and the PTC mesh frame has the same thickness as the electrode. This can isolate the negative electrode current collector and negative electrode active material from the positive electrode current collector and positive electrode active material during needle penetration, thus minimizing the needle penetration current and preventing the battery from catching fire or exploding.

[0128] At the same time, whether the positive or negative electrode uses a composite current collector, it is effective against external short circuits and extreme high currents, which can prevent thermal runaway.

[0129] Comparative Example 1 uses a conventional current collector design and has the highest rate discharge capacity. However, after the external short circuit test, the battery swelled significantly due to the excessively high temperature, and the needle puncture immediately caused it to catch fire and explode.

[0130] Comparative Example 2 shows that the surface of the negative electrode current collector is covered with a carbon layer with PTC effect, which leads to a decrease in battery rate performance. The PTC layer on the surface of the negative electrode current collector can effectively improve the safety of external short circuit, but in the nail penetration test, the same phenomenon as in Example 3 occurs, and the effect of improving the safety of nail penetration is limited.

[0131] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0132] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A lithium-ion battery current collector, characterized by, The grid framework and the metal film are included. The material of the grid framework includes positive temperature coefficient material. The metal films are arranged in the grid holes of the grid framework, and the metal films in adjacent grid holes are independent of each other. The thickness of the metal film is less than the thickness of the grid framework, and the thickness of the grid framework is less than or equal to the thickness of the electrode sheet made of the lithium ion battery current collector.

2. The lithium-ion battery current collector of claim 1, wherein, The material of the grid framework further includes conductive material. The positive temperature coefficient material is one or more of high polymer PTC thermistor material or ceramic PTC thermistor material. The conductive material is one or more of carbon, Al, Cu or conductive polymer.

3. The lithium-ion battery current collector of claim 1, wherein, The material of the metal film is Al or Cu. When the lithium ion battery current collector is used as a negative electrode current collector, the material of the metal film is Cu, and the thickness of the metal film is 4-10 um. When the lithium ion battery current collector is used as a positive electrode current collector, the material of the metal film is Al, and the thickness of the metal film is 8-25 um.

4. The lithium-ion battery current collector of claim 1, wherein, The cross section of the grid frame is rectangular, and the width of the grid frame is 0.1mm-2mm; the size of the grid hole is 0.1~10cm 2 ; The number of grid holes in the grid framework of a single current collector is determined according to the following formula: wherein , is the battery mass, is the internal resistance of a battery employing a conventional current collector, which is identical to the battery employing a conventional current collector except that the material of the current collector is different.

5. A lithium-ion battery current collector according to any one of claims 1 to 4, wherein the carbon nanotube layer is a single-walled carbon nanotube layer. The preparation method includes: S1: forming the material powder of the grid framework by laser printing to obtain the grid framework; S2: performing pressing treatment on the grid framework to make the surface flat and to make the thickness of the grid framework reach the preset thickness; S3: covering the whole metal film on the grid framework and connecting the metal film and the grid framework by laser welding, electroplating or rolling; S4: roughening the surface of the metal film by laser or ultrasonic treatment; S5: cutting the whole metal film into a plurality of metal films arranged in the grid holes to make the metal films in adjacent grid holes independent of each other; S6: performing pressing treatment and cutting on the product obtained in step S5.

6. A lithium-ion battery electrode, characterized in that, The lithium ion battery current collector according to any one of claims 1-5 is included. The lithium ion battery current collector is coated with electrode active material, conductive agent and binder.

7. A lithium-ion battery electrode according to claim 6, wherein, The preparation method includes: S1: uniformly mixing electrode active material powder, conductive agent powder and binder powder to obtain mixed powder; S2: performing heating and pre-pressing treatment on the mixed powder, the heating temperature is 60-150 ℃, and the pre-pressing thickness is 40-200 um to obtain an electrode material layer; S3: placing the electrode material layer into a mold, the mold is provided with a groove, one side of the groove is provided with a tab platform, and the electrode material layer is placed in the groove; S4: placing the current collector into the mold, wherein the tab of the current collector is located on the tab platform, and the other part of the current collector is located above the electrode material layer; S5: covering another electrode material layer obtained by step S2 above the current collector to form an electrode material layer-current collector-electrode material layer structure; S6: performing hot pressing on the electrode material layer-current collector-electrode material layer structure, the heating temperature is 60-150 ℃, and the thickness of the compacted electrode is 60-400 um, and the binder in the electrode material layer is bonded to the current collector under the heating condition.

8. A lithium-ion battery, characterized by The positive electrode or the negative electrode of the lithium ion battery is the lithium ion battery electrode according to claim 6 or 7.

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