Pole piece, battery cell and lithium battery
By using a nano-insulating layer and blind hole structure on the electrode, the problem of space occupied by the diaphragm and insulating glue is solved, the battery capacity and charge and discharge performance are improved, and the risk of short circuit is reduced.
Patent Information
- Application Number
- CN202422673686.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-01
- Publication Date
- 2025-10-03
- Estimated Expiration
- 2034-11-01
AI Technical Summary
In existing lithium-ion batteries, the battery capacity is difficult to increase because the diaphragm and insulating glue occupy a large volume space. In addition, the small pore size of the diaphragm affects the fluidity of the electrolyte, limiting the charge and discharge rate.
A nano-insulating layer is used to cover the electrode, and blind holes are set on the nano-insulating layer to replace traditional insulating glue and diaphragms, thereby improving the utilization rate of the internal space of the battery, and forming a pore structure through laser etching to enhance the fluidity of the electrolyte and the ion migration rate.
It improves the battery capacity and charge and discharge rate performance, avoids the obstruction of the diaphragm to the electrolyte, reduces the risk of internal short circuit in the battery, and improves the overall efficiency and reliability of the battery.
Smart Images
Figure CN223414091U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of lithium batteries, in particular to a pole piece, a battery core and a lithium battery. Background Art
[0002] Lithium-ion batteries, with their high energy density, long cycle life, low self-discharge, no memory effect, and environmental friendliness, have emerged as a new generation of batteries that have seen rapid development over the past decade. They are widely used in portable electronic devices such as mobile phones and computers, as well as electric vehicles. As people's quality of life improves, the demand for fast-charging performance in various electronic devices is increasing. This has ushered in a new era for lithium-ion batteries, with their capacity and charge-discharge performance becoming crucial metrics across various applications.
[0003] Existing lithium-ion batteries typically coat the current collectors of the electrode sheets with active materials. A separator is used to insulate the cathode and anode sheets, preventing contact and potentially affecting battery performance. However, thicker separators occupy more space within the battery, reducing the volume available for the electrode sheets and making it difficult to increase battery capacity. Furthermore, the small pore size of the separator reduces interfacial electrolyte fluidity, impacting battery charge and discharge rates. Utility Model Content
[0004] The main purpose of the utility model is to provide a pole piece, which aims to solve the problem that insulating materials such as diaphragms and adhesive tapes occupy the internal volume space of the battery and make it difficult to increase the battery capacity.
[0005] To achieve the above-mentioned purpose, the present invention provides a pole piece, which includes:
[0006] A current collector, wherein one end of the current collector is provided with a tab, and at least one side of the current collector is provided with an active material layer;
[0007] A nano-insulating layer covers at least one side of the pole piece, and the nano-insulating layer and the active material layer are located on the same side, and the nano-insulating layer is structured with a plurality of blind holes.
[0008] In some embodiments, the opening of the blind hole faces the surface of the nano-insulating layer away from the current collector.
[0009] In some embodiments, the thickness of the nano-insulating layer is 2 μm to 5 μm.
[0010] In some embodiments, the blind hole has a diameter of 5 μm to 15 μm.
[0011] In some embodiments, the ratio of the depth of the blind hole to the thickness of the pole piece ranges from 0.1 to 0.4.
[0012] In some embodiments, the hole spacing between the plurality of blind holes ranges from 100 um to 1000 um.
[0013] In some embodiments, a plurality of grooves are arranged at intervals on the active material layer.
[0014] In some embodiments, the material of the nano-insulating layer is nano-aluminum oxide or nano-silicon dioxide.
[0015] In some embodiments, the nano-insulation layer covers the pole piece, and the blind holes on two opposite sides of the nano-insulation layer are staggered.
[0016] In some embodiments, the tab is integrated with the current collector.
[0017] The present invention further provides a battery cell, comprising an anode sheet and a cathode sheet, wherein the anode sheet and the cathode sheet are both the electrode sheets according to any one of the aforementioned embodiments.
[0018] In some embodiments, the anode sheet and the cathode sheet each have only one side provided with a nano-insulating layer, and the side of the cathode sheet provided with the nano-insulating layer abuts against the side of the anode sheet not provided with the nano-insulating layer.
[0019] In some embodiments, the length of the tab of the anode sheet is 9 mm to 28 mm.
[0020] The present invention further provides a lithium battery, comprising a housing and the battery cell described in the aforementioned embodiment, wherein the battery cell is disposed in the housing.
[0021] The utility model uses a thinner nano-insulating layer to cover the electrode pieces, so that the electrode pieces can be fully isolated and protected by the nano-insulating layer, releasing the internal space of the battery occupied by the diaphragm, so that more active material layers can be accommodated in the same volume, thereby increasing the battery capacity, avoiding the diaphragm's obstruction to the electrolyte inside the battery, and improving the battery charge and discharge rate. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 A cross-sectional view of an embodiment of a battery cell in the prior art;
[0023] Figure 2 This is a top view of an embodiment of a pole piece of the present utility model;
[0024] Figure 3 This is a cross-sectional view of another embodiment of the pole piece of the present invention;
[0025] Figure 4 This is a cross-sectional view of another embodiment of the pole piece of the present utility model;
[0026] Figure 5This is a cross-sectional view of another embodiment of the pole piece of the present utility model;
[0027] Figure 6 This is a cross-sectional view of another embodiment of the battery cell of the present invention.
[0028] Reference numerals:
[0029] 100, pole piece; 110, current collector; 111, pole tab; 112, active material layer; 120, nano-insulating layer; 121, blind hole; 200, diaphragm; 300, battery cell; 310, anode piece; 320, cathode piece. DETAILED DESCRIPTION
[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the schemes in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0031] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0032] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element.
[0033] In addition, the descriptions of "first," "second," etc. in this utility model are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this utility model.
[0034] The present invention proposes a pole piece 100, such as Figure 2-Figure 5 As shown, the pole piece 100 includes:
[0035] A current collector 110 , wherein a tab 111 is provided at one end of the current collector 110 , and an active material layer 112 is provided on at least one side of the current collector 110 ;
[0036] The nano-insulating layer 120 covers at least one side of the electrode 100 , and the nano-insulating layer 120 and the active material layer 112 are located on the same side. The nano-insulating layer 120 is constructed with a plurality of blind holes 121 .
[0037] Reference Figure 1 In the prior art, in order to prevent the positive electrode sheet 100 and the negative electrode sheet 100 in the battery cell 300 from being directly connected, a separator 200 is often provided between the two. In addition, in order to prevent burrs generated during welding of the tab 111, or lithium deposition in the active material layer 112 during use, thereby forming lithium dendrites that may damage the tab 100 or the separator 200, an insulating glue is also provided on the tab 111 and the current collector 110. Since the thickness of the insulating glue is often greater than 12 μm and the thickness of the separator 200 is often greater than 5 μm, the two greatly compress the available space of the battery and reduce the battery capacity.
[0038] To solve this problem, the inventors of this application use a nano-insulating layer 120 to cover at least one side of the electrode 100, that is, to cover one side of the current collector 110 and the active material layer 112 arranged on the side of the current collector 110, or to cover both sides of the electrode 100 with the nano-insulating layer 120. Figure 3-Figure 5 First, an active material layer 112 is coated on the surface of the current collector 110, and then a nano-insulating layer 120 is covered on the entire electrode 100 by rolling. The nano-insulating layer 120 can be made of an oxide nanomaterial or a silicon oxide nanomaterial, such as nano-aluminum oxide, nano-zinc oxide, nano-titanium oxide, or nano-silicon dioxide. All of these materials have high insulation properties and a loose porous structure that facilitates ion diffusion.
[0039] The current collector 110, a crucial component of the electrode 100, is typically made of a material with low resistance and good electrical conductivity, such as copper foil, aluminum foil, or porous carbon materials. This allows the current collector 110 to effectively conduct current, reducing internal resistance within the battery and improving overall battery efficiency. The electrode 100 can be divided into an anode 310 and a cathode 320. The anode 310 typically uses copper foil as the current collector 110, while the cathode 320 typically uses aluminum foil as the current collector 110.
[0040] In order to store sufficient electrical energy and ensure that lithium ions can flow freely within the electrode 100, an active material layer 112 is provided on at least one surface of the current collector 110. The active material layer 112 can continuously cover the surface of the current collector 110, or can be evenly or unevenly spaced on the current collector 110. The active material layer 112 is typically adhered to the current collector 110 by rolling, so its surface is flat. However, laser drilling can also be used to create undulations on the surface of the active material layer 112 to accommodate more electrolyte and reduce the transmission path of lithium ions.
[0041] After the nano-insulating layer 120 is coated on the electrode 100, it is necessary to use laser etching to punch out several blind holes 121 to form an insulating nano-layer electrode 100 with a pore structure, thereby improving the interface liquid retention capacity and ion migration rate, increasing the fluidity of the electrolyte and thus improving the battery charge and discharge rate performance, while avoiding damage to the active material layer 112 and not causing excessive impact on the battery capacity.
[0042] This embodiment uses a thinner nano-insulation layer 120 in place of the insulating adhesive and separator 200 to fully isolate and protect the electrode 100. This frees up the internal battery space occupied by the insulating adhesive and separator 200, allowing it to be used to increase the thickness of the active material layer 112, thereby increasing the battery capacity. Furthermore, since the insulating layer's viscosity and adsorption capacity decrease after being soaked in electrolyte, making it prone to falling off, the nano-insulation layer 120 is resistant to electrolyte corrosion and soaking, resulting in a higher adhesion than the insulating adhesive, thus avoiding the risk of thermal failure of the battery.
[0043] In some embodiments, the openings of the blind holes 121 face the surface of the nano-insulating layer 120 away from the current collector 110. This facilitates the storage of electrolyte in the blind holes 121, thereby improving the interface liquid retention capacity and ion migration rate.
[0044] In some embodiments, the thickness of the nano-insulating layer 120 is 2 μm to 5 μm. The thickness of the nano-insulating layer 120 is controlled within an appropriate range. If the thickness of the nano-insulating layer 120 is less than 2 μm, the depth of the blind holes in the nano-insulating layer 120 is difficult to control, resulting in the problem of internal short-circuit wind caused by the diffusion of anode and cathode dust. If the thickness of the nano-insulating layer 120 is greater than 5 μm, the internal space of the battery is compressed, resulting in a reduction in battery capacity. Preferably, the thickness of the nano-insulating layer 120 is set to 3 μm to ensure sufficient contact between the electrolyte and the active material layer 112 while minimizing the occupation of the internal space of the battery by the nano-insulating layer 120, thereby increasing the battery capacity.
[0045] like Figure 2As shown, in some embodiments, the aperture of the blind hole 121 is 5μm to 15μm. Similar to the previous embodiment, when the aperture is less than 5μm, the amount of electrolyte that can be stored in the blind hole 121 is less, resulting in a decrease in the charge and discharge rate of the battery; when the aperture is greater than 15μm, the protection performance of the nano-insulation layer 120 on the electrode 100 is weakened. Excessively large apertures may cause the cathode and anode sheets to diffuse and contact the interface due to internal stress, resulting in insulation failure and affecting the normal use of the battery. Preferably, the aperture of the blind hole 121 is set to 10μm, so that the blind hole 121 can store enough electrolyte without affecting the insulation function of the nano-insulation layer 120.
[0046] In some embodiments, the ratio of the depth of the blind hole 121 to the thickness of the pole piece 100 is in the range of 0.1 to 0.4.
[0047] In actual production, since the nano-insulation layer 120 is applied to the electrode 100 by roller pressing, it is difficult to ensure a sufficiently uniform thickness of the nano-insulation layer 120, especially when the active material layer 112 is uneven. Therefore, when drilling, the ratio of the depth of the blind hole 121 to the thickness of the electrode 100 is usually controlled to be less than 0.4. This prevents the insulation capability of the nano-insulation layer 120 from failing and avoids the diffusion of dust from the cathode and anode electrodes after the nano-insulation layer 120 is penetrated, which may cause a short circuit. Controlling the ratio of the depth of the blind hole 121 to the thickness of the electrode 100 to be greater than 0.1 ensures that the volume of the blind hole 121 is larger, and the electrolyte infiltration effect is better.
[0048] In some embodiments, the hole spacing between the blind holes 121 ranges from 100 um to 1000 um.
[0049] Because the tolerance for laser drilling is ±50 μm, if the pitch of blind vias 121 is less than 100 μm, overlapping holes are likely to occur, resulting in penetration of the nano-insulation layer 120. If the pitch is greater than 1000 μm, the coverage of blind vias 121 is low, resulting in poor overall liquid retention and rate performance. Therefore, setting the pitch of blind vias 121 within 100 μm to 1000 μm reduces the probability of overlapping holes while ensuring good liquid retention and rate performance of the nano-insulation layer 120.
[0050] like Figure 4 As shown, in some embodiments, a plurality of grooves are provided at intervals on the active material layer 112. This increases the contact area between the active material layer 112 and the electrolyte, ensuring that more active material is in contact with the electrolyte, making the exchange and transfer of lithium ions more convenient, and at the same time reducing the diffusion path of protons or ions in the battery, thereby further improving the charge and discharge rate of the battery.
[0051] In some embodiments, the material of the nano-insulating layer 120 is nano-aluminum oxide or nano-silicon dioxide.
[0052] In some embodiments, the nano-insulation layer 120 covers the electrode 100, and the blind holes 121 on the two opposite sides of the nano-insulation layer 120 are staggered. The staggered blind holes 121 can reduce the probability of the electrode 100 being pierced and improve the consistency of the liquid retention interface.
[0053] like Figure 2 As shown, in some embodiments, the tab 111 is integrated with the current collector 110. Laser cutting can be used to cut the current collector 110 and the tab 111 from a whole piece of foil, so that the tab 111 and the current collector 110 do not need to be connected by welding or other methods. This simplifies the manufacturing process of the battery, reduces the welding steps, and avoids problems such as burrs that may be generated during the welding process. It can also reduce the contact resistance between the tab 111 and the current collector 110, improve the electrical conductivity of the battery, and thus reduce energy loss during the use of the battery. At the same time, the integrated pole piece 100 has better mechanical properties, which can reduce the loosening or breakage that may occur during use, improve the reliability and durability of the battery, and compared with the conventional pole piece 100, this design is thinner, further freeing up the internal space of the battery and increasing the battery capacity.
[0054] The present invention further provides a battery cell 300 comprising an anode sheet 310 and a cathode sheet 320, each of which is the electrode sheet 100 of any of the aforementioned embodiments. The specific structures of the anode sheet 310 and the cathode sheet 320 are similar to those of the aforementioned embodiments. Since the anode sheet 310 and the cathode sheet 320 of this embodiment utilize all the technical solutions of all the aforementioned embodiments, they at least have all the technical effects of the technical solutions of the aforementioned embodiments, and therefore will not be described in detail here. The battery cell 300 of this embodiment does not require a separator 200; instead, the anode sheet 310 and the cathode sheet 320 are isolated by the nano-insulating layer 120 on them.
[0055] like Figure 6 As shown, in some embodiments, the anode sheet 310 and the cathode sheet 320 are each provided with the nano-insulating layer 120 on only one side, and the side of the cathode sheet 320 provided with the nano-insulating layer 120 abuts against the side of the anode sheet 310 not provided with the nano-insulating layer 120. Anode sheets 310 and cathode sheets 320 each having only a single nano-insulating layer 120 are required to ensure that the electrodes 100 do not contact each other.
[0056] In some embodiments, the length of the tab 111 of the anode sheet 310 is 9 mm to 28 mm. When producing a fully sealed battery, it is usually necessary to first fold the tab 111 of the anode sheet 310 and weld it to the negative electrode interface on the battery casing. This requires that the tab 111 of the anode sheet 310 has sufficient length. The specific length of the tab 111 needs to be determined according to actual use requirements. Among them, the 9mm tab 111 is suitable for smaller batteries. If the length of the tab 111 is less than 9mm, it will affect the normal installation of the lithium battery cell 300. The 28mm tab 111 is suitable for large batteries. If the length of the tab 111 is greater than 28mm, it will compress the internal space of the lithium battery and increase the difficulty of installation.
[0057] The present invention further provides a lithium battery comprising a housing and the battery cell 300 described in the aforementioned embodiment, wherein the battery cell 300 is encapsulated within the housing. The housing may also be an aluminum-plastic film. Specifically, the lithium battery of this embodiment can be used in terminal devices such as mobile phones, tablet computers, laptop computers, and smart wearable devices. While maintaining a similar volume, the battery has a greater capacity, thereby extending the life of various electrical devices.
[0058] The above description is only part or preferred embodiments of the present invention. Neither the text nor the drawings can limit the scope of protection of the present invention. All equivalent structural transformations made by using the contents of the present invention specification and drawings under the overall concept of the present invention, or direct / indirect application in other related technical fields are included in the scope of protection of the present invention.
Claims
1. A pole piece, characterized in that: The pole piece includes: A current collector, wherein one end of the current collector is provided with a tab, and at least one side of the current collector is provided with an active material layer; A nano-insulating layer is provided on a surface of the active material layer away from the current collector, and the nano-insulating layer is structured with a plurality of blind holes.
2. The pole piece according to claim 1, characterized in that: The opening of the blind hole faces the surface of the nano-insulating layer away from the current collector.
3. The pole piece according to claim 1, characterized in that: The thickness of the nano insulating layer is 2 μm to 5 μm.
4. The pole piece according to claim 3, characterized in that: The blind hole has a diameter of 5 μm to 15 μm.
5. The pole piece according to claim 1, characterized in that: The ratio of the depth of the blind hole to the thickness of the pole piece is in the range of 0.1 to 0.
4.
6. The pole piece according to claim 1, characterized in that: The hole spacing between the blind holes ranges from 100um to 1000um.
7. The pole piece according to claim 1, characterized in that: A plurality of grooves are arranged at intervals on the active material layer.
8. The pole piece according to claim 1, characterized in that: The material of the nano insulating layer is nano aluminum oxide or nano silicon dioxide.
9. The pole piece according to claim 1, characterized in that: The nano insulating layer covers the pole piece, and the blind holes on two opposite sides of the nano insulating layer are staggered.
10. The pole piece according to any one of claims 1 to 9, characterized in that: The tabs are integrated with the current collector.
11. A battery cell, characterized in that: It comprises an anode sheet and a cathode sheet, and both the anode sheet and the cathode sheet are the electrode sheets according to any one of claims 1-10.
12. The battery cell according to claim 11, characterized in that: The anode sheet and the cathode sheet are each provided with a nano-insulating layer on only one side, and the side of the cathode sheet provided with the nano-insulating layer abuts against the side of the anode sheet not provided with the nano-insulating layer.
13. The battery cell according to claim 12, characterized in that: The length of the tab of the anode sheet is 9 mm to 28 mm.
14. A lithium battery, characterized in that: The invention comprises a shell and the battery core according to any one of claims 11 to 13, wherein the battery core is arranged in the shell.