Electrochemical apparatus, its manufacturing method, and electronic apparatus

Abstract

The present application provides an electrochemical device, a method for manufacturing the same, and an electronic device. The electrochemical device includes an electrode assembly, the electrode assembly includes a positive electrode sheet and a negative electrode sheet, the positive electrode sheet includes a positive electrode current collector and a first positive electrode active material layer disposed on the surface of the positive electrode current collector, the negative electrode sheet includes a negative electrode current collector and a first negative electrode active material layer disposed on the surface of the negative electrode current collector, the first negative electrode active material layer includes a lithium replenishment region and a lithium non-replenishment region, the negative electrode sheet is provided with a first groove that penetrates the first negative electrode active material layer and exposes the surface of the negative electrode current collector, the positive electrode sheet further includes a first insulating layer attached to the first positive electrode active material layer facing the first groove, and the lithium non-replenishment region is located within the orthographic projection of the first insulating layer onto the negative electrode sheet. The technical solution provided by the present application can reduce the risk of lithium precipitation in the negative electrode sheet and improve the safety of the electrochemical device by adjusting the dimensions of the lithium non-replenishment region around the position of the first groove.

Description

Cross-reference to Related Applications

[0001] This application claims priority based on a Chinese patent application filed with the China National Intellectual Property Administration on July 1, 2022, with an application number of 202210763419.7 and an invention title of "Electrochemical Device, Its Manufacturing Method, and Electronic Device". Here, all of its content is incorporated into this application by reference.

Technical Field

[0002] This application relates to the field of electrochemical technology, and particularly to electrochemical devices, their manufacturing methods, and electronic devices.

Background Art

[0003] Lithium-ion batteries have characteristics such as high energy density, high operating voltage, low self-discharge rate, small size, and light weight, so they are widely applied in the field of consumer electronics products. With the rapid development of portable electronic devices, the requirements for the energy density, cycle performance, etc. of lithium-ion batteries are becoming increasingly high. In order to further increase the energy density of lithium-ion batteries, lithium can be replenished to the negative electrode sheet. However, lithium precipitation is likely to occur on the lithium-supplemented negative electrode sheet, which is disadvantageous for improving the safety of lithium-ion batteries.

Summary of the Invention

[0005] A first aspect of the present invention provides an electrochemical apparatus including an electrode assembly. The electrode assembly includes a positive electrode piece and a negative electrode piece, the positive electrode piece includes a positive electrode current collector and a first positive electrode active material layer placed on the surface of the positive electrode current collector, the negative electrode piece includes a negative electrode current collector and a first negative electrode active material layer placed on the surface of the negative electrode current collector, the first negative electrode active material layer includes a lithium-replenished region and a lithium-unreplenished region, the negative electrode piece has a first groove that penetrates the first negative electrode active material layer and exposes the surface of the negative electrode current collector, the lithium-unreplenished region has a first edge placed along a first direction and a first edge placed along a second direction The positive electrode piece comprises a second edge connected to a groove, the first direction being the length direction of the negative electrode piece, the second direction being the width direction of the negative electrode piece, the distance between the first edge and the adjacent edge of the first groove being A1 mm, the dimension of the first groove in the second direction being B1 mm, the positive electrode piece further includes a first insulating layer attached to a first positive electrode active material layer facing the first groove, the lithium-unreplenished region is located within the orthogonal projection of the first insulating layer onto the negative electrode piece, the dimension of the first insulating layer in the second direction being C1 mm, and 0.5 ≤ A1 ≤ C1 - B1 + 1.

[0006] The beneficial effects of the embodiment of the present invention are as follows: By providing a lithium-unreplenished region in the first negative electrode active material layer around the location of the first groove in the negative electrode piece, the risk of lithium deposition in the negative electrode piece is reduced, and the lithium-unreplenished region can absorb more lithium ions from the positive electrode compared to the lithium-replenished region. The positive electrode piece further includes a first insulating layer attached to the first positive electrode active material layer facing the first groove. During the cycle process of the electrochemical apparatus, the binding force of the first insulating layer weakens due to the expansion and contraction of the first positive electrode active material layer and / or the influence of the electrolyte, causing lithium ions in the first positive electrode active material layer covered by the first insulating layer to migrate and precipitate, and be absorbed into the corresponding negative electrode piece. Because a lithium-unreplenished region is located around the position of the first groove in the negative electrode piece, the local capacitance is increased, allowing lithium ions that have escaped from the region covered by the opposing first insulating layer to be contained. This improves the overall capacitance of the electrochemical apparatus by replenishing lithium, while also reducing the risk of lithium deposition around the first groove in the negative electrode piece, thereby improving the safety of the electrochemical apparatus.

[0007] In one embodiment of the present invention, the distance between the second edge and the adjacent edge of the first groove is A2 mm, the dimension of the first groove in the first direction is B2 mm, and the dimension of the first insulating layer in the first direction is C2 mm, such that 0.5 ≤ A2 ≤ 0.5 × (C2 - B2) + 1. By adjusting A2 within the above range, the risk of lithium deposition around the first groove in the negative electrode piece can be further reduced, thereby improving the safety of the electrochemical apparatus.

[0008] In one embodiment of the present application, 0.5 ≤ A1 ≤ 9 and 0.5 ≤ A2 ≤ 9. By adjusting the dimensions of the lithium-unreplenished region to satisfy the above relationship, the risk of lithium deposition in the negative electrode piece can be reduced, the safety of the electrochemical apparatus can be improved, and an electrochemical apparatus with high capacity can be obtained.

[0009] In one embodiment of the present invention, 18 ≤ B1 ≤ 22 and 9 ≤ B2 ≤ 13. By adjusting the dimensions of the first groove to satisfy the above relationship, it is advantageous for manufacturing the first groove and reduces the impact of excessive dimensions on the capacity of the electrochemical apparatus.

[0010] In one embodiment of the present application, 25 ≤ C1 ≤ 29 and 23 ≤ C2 ≤ 27. By adjusting the dimensions of the first insulating layer to satisfy the above relationship, it is advantageous to improve the accuracy of attachment to the first insulating layer, reduce the risk of lithium deposition at the position of the first groove in the negative electrode piece, improve the safety of the electrochemical apparatus, and reduce the impact of excessive dimensions of the first insulating layer on the capacity of the electrochemical apparatus.

[0011] In one embodiment of the present application, 1.25 ≤ A1 ≤ 9 and 1.25 ≤ A2 ≤ 9. By adjusting the dimensions of the lithium-unreplenished region to satisfy the above relationship, the risk of lithium deposition in the negative electrode piece can be reduced, improving the safety and cycle capacity retention rate of the electrochemical apparatus.

[0012] In one embodiment of the present invention, when observed from the thickness direction of the negative electrode piece, the lithium replenishment region is provided with a stripe portion, the width of the stripe portion being 0.1 mm to 2 mm in the first direction, and / or the thickness of the stripe portion being 0.04 μm to 0.5 μm in the thickness direction. The negative electrode piece having the above characteristics can improve the initial Coulomb efficiency of the negative electrode piece, is advantageous for improving the energy density of the electrochemical apparatus, and is also advantageous for improving the manufacturing efficiency of the lithium replenishment region.

[0013] In one embodiment of the present invention, the material of the lithium replenishment region comprises at least one of lithium carbonate, lithium oxide, lithium nitride, or lithium fluoride. In the process of replenishing lithium to the negative electrode piece, the lithium metal reacts with the air environment due to its high reactivity and reacts in the chemical conversion process of the electrochemical apparatus to form a layer of lithium-containing compound on the surface of the first negative electrode active material layer, the main component of which the lithium-containing compound comprises at least one of lithium carbonate, lithium nitride, lithium fluoride, or lithium oxide. The negative electrode piece having the above features can improve the initial Coulomb efficiency of the negative electrode piece, which is advantageous for improving the energy density of the electrochemical apparatus, can improve the surface resistance of the negative electrode piece, which is advantageous for reducing the risk of short circuits and short-circuit currents, and the material of the lithium replenishment region covering the surface of the negative electrode active material can reduce the risk of its solid electrolyte interface film being damaged.

[0014] In one embodiment of the present application, the first insulating layer includes at least one of single-sided tape, double-sided tape, or hot-melt tape. Selecting the first insulating layer from the above range is advantageous in reducing the risk of lithium deposition at the location of the first groove in the negative electrode piece and improving the safety of the electrochemical apparatus.

[0015] In one embodiment of the present invention, the negative electrode piece further includes a negative electrode tab that is installed in a first groove and electrically connected to a negative electrode current collector. By installing such a structure, the internal resistance of the electrochemical apparatus can be reduced and the charging rate of the electrochemical apparatus can be improved.

[0016] In one embodiment of the present invention, the negative electrode piece further includes a second insulating layer installed on the negative electrode tab, wherein the positive projection of the second insulating layer onto the negative electrode piece is located within a lithium-unreplenished region. This reduces the risk of short circuits between the positive and negative electrodes due to burrs on the edges of the negative electrode tab and the connection between the negative electrode tab and the negative electrode current collector, thereby improving the safety of the electrochemical apparatus.

[0017] In one embodiment of the present invention, the first negative electrode active material layer contains a negative electrode active material, and the negative electrode active material contains a silicon-based material. This is advantageous for improving the energy density of the electrochemical apparatus.

[0018] In one embodiment of the present invention, the first groove does not penetrate the first negative electrode active material layer in the second direction. By installing such a structure, the impact of the groove's presence on the capacity of the electrochemical apparatus can be reduced.

[0019] The second aspect of this application provides an electronic device, including an electrochemical apparatus provided in the first aspect of this application. Since the electrochemical apparatus provided in this application has good safety performance, the electronic device provided in this application has good safety performance.

[0020] The third aspect of this application provides a method for manufacturing an electrochemical apparatus provided in the first aspect of this application. A first negative electrode active material layer is provided on the surface of the negative electrode current collector, the negative electrode piece has a first groove penetrating the first negative electrode active material layer, and the first negative electrode active material layer has a lithium-replenished region and a lithium-unreplenished region. A first positive electrode active material layer is placed on the surface of the positive electrode current collector, and a first insulating layer is attached to the first positive electrode active material layer. The method involves stacking a negative electrode piece and a positive electrode piece and winding them together as an electrode assembly, wherein the first negative electrode active material layer faces the first positive electrode active material layer, and the positive projection of the first insulating layer onto the negative electrode piece covers the lithium-unreplenished region.

[0021] An electrochemical apparatus manufactured by the method provided in the third aspect of this application can reduce the risk of lithium deposition in the negative electrode and improve the safety of the electrochemical apparatus.

[0022] In one embodiment of the present application, at least one of lithium foil or lithium powder is used on the surface of the first negative electrode active material layer to provide a lithium replenishment region in the first negative electrode active material layer. By providing the lithium replenishment region in the above manner, the initial Coulombic efficiency of the negative electrode sheet can be improved, which is advantageous for improving the energy density of the electrochemical device.

[0023] The present application provides an electrochemical device, a manufacturing method thereof, and an electronic device. By providing a lithium non-replenished region in the first negative electrode active material layer around the position of the first groove in the negative electrode sheet, the risk of lithium precipitation on the negative electrode sheet is reduced. Compared with the lithium replenishment region, the lithium non-replenished region can occlude more lithium ions from the positive electrode. The positive electrode sheet further includes a first insulating layer attached to the first positive electrode active material layer facing the first groove. During the cycling process of the electrochemical device, the adhesion of the first insulating layer becomes weak due to the expansion and contraction of the first positive electrode active material layer and / or the influence of the electrolyte, and lithium ions in the first positive electrode active material layer covered by the first insulating layer move and precipitate and are occluded in the corresponding negative electrode sheet. Since a lithium non-replenished region is provided around the position of the first groove in the negative electrode sheet, the local capacity increases, and the lithium ions escaping from the region covered by the opposing insulating layer can be accommodated. Thereby, by replenishing lithium, the capacity of the entire electrochemical device can be improved, and the risk of lithium precipitation around the first groove in the negative electrode sheet can be reduced. According to the technical solution of the present application, the risk of lithium precipitation in the negative electrode sheet can be reduced, and the safety of the electrochemical device can be improved. Of course, when implementing any embodiment of the present application, it is not necessary to achieve all the above advantages simultaneously.

Brief Description of the Drawings

[0024] To more clearly explain the technical solutions of the present application and the prior art, the following briefly describes the embodiments and the drawings required for the prior art. Of course, the drawings described below are only a part of the embodiments of the present application. [Figure 1] FIG. 1 is a schematic configuration diagram of an electrode assembly in an embodiment of the present application. [Figure 2]Figure 2 is a schematic configuration diagram of the positive electrode sheet in the embodiment of the present application. [Figure 3] Figure 3 is a schematic configuration diagram of the negative electrode sheet in the embodiment of the present application. [Figure 4] Figure 4 is a cross-sectional view along the thickness direction of the positive electrode sheet in the embodiment of the present application. [Figure 5] Figure 5 is a cross-sectional view along the thickness direction of the A-A cross-section of the negative electrode sheet in the embodiment of the present application, and the position of the A-A cross-section is shown in Figure 3. [Figure 6] Figure 6 is a cross-sectional view along the thickness direction of the positive electrode sheet in another embodiment of the present application. [Figure 7] Figure 7 is a cross-sectional view along the thickness direction of the A-A cross-section of the negative electrode sheet in another embodiment of the present application, and the position of the A-A cross-section is shown in Figure 3. [Figure 8] Figure 8 is a scanning electron microscope (SEM) photograph of the lithium replenishment region in the negative electrode sheet in the embodiment of the present application. [Figure 9] Figure 9 is a SEM photograph of the lithium non-replenished region around the position of the first groove in the negative electrode sheet in the embodiment of the present application. [Figure 10] Figure 10 is a SEM photograph of the lithium-containing compound layer on the surface of the negative electrode sheet in the embodiment of the present application.

Embodiments for Carrying out the Invention

[0025] In order to make the object, technical solution, and advantages of the present application clearer, the present application will be described in more detail below with reference to the drawings and embodiments. Of course, the described embodiments are only some embodiments of the present application, not all embodiments. All other technical solutions obtained by those skilled in the art based on the embodiments in the present application are included in the protection scope of the present application.

[0026] In the specific embodiment of the present application, the lithium-ion battery is used as an example of the electrochemical device to describe the present application, but the electrochemical device of the present application is not limited to the lithium-ion battery.

[0027] Conventional lithium replenishment techniques have resulted in a tendency for lithium deposition to occur in the negative electrode piece, which is detrimental to improving the safety of lithium-ion batteries. The inventors have discovered that when replenishing lithium, by replenishing lithium to certain areas of the negative electrode piece and not replenishing lithium to other areas, the risk of lithium deposition in the negative electrode piece can be reduced when increasing the capacity of the lithium-ion battery, thereby improving the safety of the lithium-ion battery.

[0028] In view of this, the first embodiment of the present application provides an electrochemical apparatus including an electrode assembly 10. As shown in Figure 1, the electrode assembly 10 includes a positive electrode piece 11 and a negative electrode piece 12. Figure 2 is a schematic diagram of the configuration of the positive electrode piece in one embodiment of the present application, Figure 3 is a schematic diagram of the configuration of the negative electrode piece in one embodiment of the present application, Figure 4 is a cross-sectional view of the positive electrode piece along the thickness direction in one embodiment of the present application, and Figure 5 is a cross-sectional view of the negative electrode piece along the thickness direction in the AA cross-section shown in Figure 3 in one embodiment of the present application. The positive electrode piece 11 includes a positive electrode current collector 111 and a first positive electrode active material layer 112 installed on the surface of the positive electrode current collector 111. The negative electrode piece 12 includes a negative electrode current collector 122 and a first negative electrode active material layer 121 installed on the surface of the negative electrode current collector 122. The first negative electrode active material layer 121 includes a lithium replenished region 123 and a lithium unreplenished region 124, the lithium unreplenished region 124 being a region of the first negative electrode active material layer 121 that does not overlap with the lithium replenished region 123. The negative electrode piece 12 is provided with a first groove 13 that penetrates the first negative electrode active material layer 121 and exposes the surface of the negative electrode current collector 122. In this embodiment, the thickness direction perpendicular to the negative electrode piece 12 is defined as the z direction, and the two directions perpendicular to the z direction are defined as the first direction (x direction) and the second direction (y direction), with the first direction (x direction) and the second direction (y direction) being perpendicular to each other. The lithium-unfilled region 124 includes a first edge 1241 installed along a first direction (x direction) and a second edge 1242 installed along a second direction (y direction) and connected to the first edge 1241, wherein the first direction (x direction) is the length direction of the negative electrode piece 12 and the second direction (y direction) is the width direction of the negative electrode piece 12. Referring to Figure 3, the distance between the first edge 1241 and the adjacent edge 131 of the first groove 13 is defined as A1 mm, that is, the distance between the first edge 1241 and the edge of the first groove 13 that extends along the first direction (x direction) and is closest to the first edge 1241 is defined as A1 mm, and the dimension of the first groove 13 in the second direction (y direction) is defined as B1 mm. The positive electrode piece 11 further includes a first insulating layer 14 attached to a first positive electrode active material layer 112 facing the first groove 13, the lithium-unreplenished region 124 is located within the positive projection of the first insulating layer 14 onto the negative electrode piece 12, the dimension of the first insulating layer 14 in the second direction (y direction) is C1 mm, and 0.5 ≤ A1 ≤ C1 - B1 + 1.

[0029] This invention reduces the risk of lithium deposition on the negative electrode piece 12 by providing a lithium-unreplenished region 124 in the first negative electrode active material layer 121 around the location of the first groove 13 on the negative electrode piece 12, and the lithium-unreplenished region 124 can absorb more lithium ions from the positive electrode compared to the lithium-replenished region 123. The positive electrode piece 11 further includes a first insulating layer 14 attached to the first positive electrode active material layer 112 facing the first groove 13. During the cycle process of the electrochemical apparatus, the binding force of the first insulating layer 14 weakens due to the expansion and contraction of the first positive electrode active material layer 112 and / or the influence of the electrolyte, causing lithium ions in the first positive electrode active material layer 112 covered by the first insulating layer 14 to migrate and precipitate, and be absorbed into the corresponding negative electrode piece 12. Since a lithium-unreplenished region 124 is provided around the position of the first groove 13 in the negative electrode piece 12, the local capacitance is increased, and lithium ions that escape from the region covered by the first insulating layer 14 can be contained. This improves the overall capacitance of the electrochemical apparatus by replenishing lithium, and also reduces the risk of lithium deposition around the first groove 13 of the negative electrode piece 12, thereby improving the safety of the electrochemical apparatus.

[0030] In one embodiment of the present invention, cross-sectional views along the thickness direction of the positive electrode piece 11 and the negative electrode piece 12 are shown as in Figures 6 and 7. The positive electrode piece 11 includes a positive electrode current collector 111 and a first positive electrode active material layer 112 installed on one surface of the positive electrode current collector 111, and the negative electrode piece 12 includes a negative electrode current collector 122 and a first negative electrode active material layer 121 installed on one surface of the negative electrode current collector 122. This also achieves the objectives of the present invention.

[0031] In one embodiment of the present invention, the distance between the second edge 1242 and the adjacent edge 132 of the first groove 13 is set to A2 mm, that is, the distance between the second edge 1242 and the edge closest to the second edge 1242 that extends along the second direction (y direction) of the first groove 13 is set to B2 mm, the dimension of the first groove 13 in the first direction (x direction) is set to B2 mm, and the dimension of the first insulating layer 14 in the first direction (x direction) is set to C2 mm, where 0.5 ≤ A2 ≤ 0.5 × (C2 - B2) + 1. By adjusting A2 within the above range, the risk of lithium deposition around the first groove 13 in the negative electrode piece 12 can be further reduced, and the safety of the electrochemical apparatus can be improved.

[0032] In one embodiment of the present application, 0.5 ≤ A1 ≤ 9 and 0.5 ≤ A2 ≤ 9. By adjusting the dimensions of the lithium-unreplenished region 124 to satisfy the above relationship, the risk of lithium deposition in the negative electrode piece 12 can be reduced, the safety of the electrochemical apparatus can be improved, and an electrochemical apparatus with high capacity can be obtained.

[0033] In one embodiment of the present application, 18 ≤ B1 ≤ 22 and 9 ≤ B2 ≤ 13, where, for example, B1 may be 18, 19, 20, 21, 22 or any range in between, and B2 may be 9, 10, 11, 12, 13 or any range in between. Adjusting the dimensions of the first groove 13 to satisfy the above relationship is advantageous for the manufacture of the first groove 13 and reduces the impact of excessive dimensions on the capacity of the electrochemical apparatus.

[0034] In one embodiment of the present application, 25 ≤ C1 ≤ 29 and 23 ≤ C2 ≤ 27, where, for example, C1 may be 25, 26, 27, 28, 29 or any range in between, and C2 may be 23, 24, 25, 26, 27 or any range in between. By adjusting the dimensions of the first insulating layer 14 to satisfy the above relationship, it is advantageous to improve the accuracy of bonding the first insulating layer 14, reduce the risk of lithium deposition at the location of the first groove 13 in the negative electrode piece 12, improve the safety of the electrochemical apparatus, and reduce the impact of excessive dimensions of the first insulating layer 14 on the capacity of the electrochemical apparatus.

[0035] In one embodiment of the present application, 1.25 ≤ A1 ≤ 9 and 1.25 ≤ A2 ≤ 9. By adjusting the dimensions of the lithium-unreplenished region 124 to satisfy the above relationship, the risk of lithium deposition in the negative electrode piece 12 can be reduced, improving the safety and cycle capacity retention rate of the electrochemical apparatus.

[0036] In one embodiment of the present invention, when observed from the thickness direction (z direction) of the negative electrode piece 12, the lithium replenishment region 123 is provided with a stripe portion, the width of the stripe portion is 0.1 mm to 2 mm in the first direction (x direction), and / or the thickness of the stripe portion is 0.04 μm to 0.5 μm in the thickness direction. The negative electrode piece 12 having the above features can improve the initial Coulomb efficiency of the negative electrode piece 12, is advantageous for improving the energy density of the electrochemical apparatus, and is also advantageous for improving the manufacturing efficiency of the lithium replenishment region. Specifically, in one embodiment, the width of the stripe portion is 0.1 mm to 2 mm in the first direction, and the thickness of the stripe portion is 0.04 μm to 0.5 μm in the thickness direction. In one embodiment, the width of the stripe portion is 0.1 mm to 2 mm in the first direction. In one embodiment, the thickness of the stripe portion is 0.04 μm to 0.5 μm in the thickness direction.

[0037] Here, the striped portion refers to the lithium ribbon with striped gaps formed during the rolling process of the lithium metal when lithium is replenished with metallic lithium foil. During the process of compounding the lithium foil with the negative electrode piece 12, the lithium ribbon with the striped gaps formed above can be retained, so the striped portion can be observed from the thickness direction (z direction) of the negative electrode piece 12. After assembling the electrochemical apparatus with the lithium-replenished negative electrode piece 12 and positive electrode piece 11, the striped portion on the surface of the negative electrode piece 12 is always retained due to the absorption of lithium metal into the negative electrode piece 12 and subsequent chemical conversion and capacitance processing. After the electrochemical apparatus has gone through the cycle process, the lithium-replenished region 123 of the negative electrode piece 12 has a striped portion, and its SEM image is shown in Figure 8, but the lithium-unreplenished region 124 around the position of the first groove 13 does not have a striped portion, and its SEM image is shown in Figure 9.

[0038] In one embodiment of the present application, the material of the lithium replenishment region 123 includes at least one of lithium carbonate, lithium oxide, lithium nitride, or lithium fluoride. In the process of replenishing lithium to the negative electrode piece 12, the lithium metal is highly reactive and reacts with air (e.g., oxygen and trace amounts of moisture) and with fluorine-containing substances in the electrolyte during the chemical conversion process of the electrochemical apparatus, forming a layer of lithium-containing compound on the surface of the first negative electrode active material layer 121, the main component of which the lithium-containing compound includes at least one of lithium carbonate, lithium nitride, lithium fluoride, or lithium oxide. After assembling the electrode assembly and injecting the electrolyte, the lithium metal rapidly reacts with the negative electrode active material, but the lithium-containing compound layer does not react with the negative electrode active material. After the active lithium metal reacts with the negative electrode active material, the lithium-containing compound layer remains on the surface of the negative electrode piece 12. As shown in Figure 10, the lithium-replenished region 123 forms a single layer of lithium-containing compound (between the two black dashed lines) on the surface of the negative electrode active material, with a thickness of 0.04 μm to 0.5 μm. The negative electrode piece 12 having the above characteristics can improve the initial Coulomb efficiency of the negative electrode piece 12, which is advantageous for improving the energy density of the electrochemical apparatus. It can also improve the surface resistance of the negative electrode piece 12, which is advantageous for reducing the risk of short circuits and short-circuit currents. Furthermore, the material of the lithium-replenished region 123 covering the surface of the negative electrode active material can reduce the risk of its solid electrolyte interface film being damaged.

[0039] In one embodiment of the present application, the first insulating layer 14 includes at least one of a single-sided tape, a double-sided tape, or a hot-melt tape. By selecting an insulating layer within the above range, it is advantageous to reduce the risk of lithium deposition at the location of the first groove 13 in the negative electrode piece 12 and to improve the safety of the electrochemical apparatus. In the present application, there are no particular restrictions on the material of the first insulating layer 14, as long as it can achieve the objectives of the present application. For example, a single-sided tape includes a base layer and an adhesive layer, and the material of the base layer includes, but is not limited to, at least one of polyfluoroolefin, polyethylene terephthalate (PET), polyimide (PI), polyamide-imide (PAI), polyvinyl chloride (PVC), or polyolefin (POF, e.g., biaxially oriented polyolefin heat shrink film), and the polyfluoroolefin includes, but is not limited to, polytetrafluoroethylene or polyvinylidene fluoride. The adhesive layer includes a binder, which includes, but is not limited to, at least one of carboxymethylcellulose, styrene-butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, fluorinated rubber, polyamide, polypropylene alcohol, sodium polyacrylate, polyetherimide, or acrylic acid ester.

[0040] In one embodiment of the present invention, the negative electrode piece 12 further includes a negative electrode tab that is installed in the first groove 13 and electrically connected to the negative electrode current collector 122, where electrically connected means that conductivity is possible between the negative electrode tab and the negative electrode current collector 122. As shown in Figure 5, in one embodiment, the first groove 13 is installed on both sides of the negative electrode current collector 122, and the negative electrode tab is installed in at least one of the first groove 13. By installing such a structure, the internal resistance of the electrochemical apparatus can be reduced and the charging rate of the electrochemical apparatus can be improved.

[0041] In one embodiment of the present application, the negative electrode tab 12 further includes a second insulating layer disposed on the negative electrode tab, and the positive projection of the second insulating layer onto the negative electrode tab 12 is located within the lithium non-supplemented region 124. The second insulating layer includes, for example, but is not limited to, a tape such as a single-sided tape. By disposing the second insulating layer as described above, the risk of short circuit between the positive and negative electrodes caused by the burrs on the edge of the negative electrode tab and the connection between the negative electrode tab and the negative electrode current collector 122 can be reduced, and the safety of the electrochemical device can be improved.

[0042] In one embodiment of the present application, the first negative electrode active material layer 121 contains a negative electrode active material, the negative electrode active material contains a silicon-based material, and the silicon-based material contains at least one of silicon, silicon oxide (SiO x , 0 < x ≤ 2), silicon alloy, or silicon-carbon composite. The negative electrode active material of the present application may include at least one of graphite, mesocarbon microbeads (MCMB), hard carbon, soft carbon, Li-Sn alloy, Li-Sn-O alloy, Sn, SnO, SnO2, lithium titanate Li4Ti5O 12 in a spinel structure, Li-Al alloy, or metallic lithium. By selecting materials within the above range, it is advantageous for improving the energy density of the electrochemical device.

[0043] In one embodiment of the present application, in the second direction, the first groove 13 does not penetrate the first negative electrode active material layer 121. By providing such a structure, the influence on the capacity of the electrochemical device caused by the installation of the groove can be reduced.

[0044] The electrochemical device of the present application is not particularly limited and may include any device that generates an electrochemical reaction. In one embodiment of the present application, the electrochemical device includes, but is not limited to, a lithium-ion secondary battery (lithium-ion battery), a lithium polymer secondary battery, or a lithium-ion polymer secondary battery. In one embodiment of the present application, the lithium-ion battery structure of the present application includes a wound structure or a stacked structure. The lithium-ion battery structure of the present application includes, but is not limited to, a soft-pack lithium-ion battery, a square hard-shell battery, or a cylindrical hard-shell battery.

[0045] This application does not impose any particular limitations on the negative electrode current collector 122, as long as it can achieve the objectives of this application. For example, the negative electrode current collector 122 may include copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, or a composite current collector. This application does not impose any particular limitations on the thickness of the negative electrode current collector, as long as it can achieve the objectives of this application. For example, the thickness of the negative electrode current collector is 4 μm to 10 μm.

[0046] In this application, the first negative electrode active material layer 121 may be installed on one surface in the thickness direction of the negative electrode current collector 122, or on two surfaces in the thickness direction of the negative electrode current collector 122. The term "surface" here may refer to the entire area of ​​the negative electrode current collector 122, or only a portion of the area of ​​the negative electrode current collector 122. There are no particular limitations to this application, as long as the objectives of this application can be achieved.

[0047] The present invention does not impose any particular limitations on the thickness of the first negative electrode active material layer 121, as long as the objective of the present invention can be achieved. For example, the thickness of the first negative electrode active material layer on one side may be 30 μm to 160 μm.

[0048] In this application, the surface of the negative electrode current collector 122 is provided with a first negative electrode active material layer 121, or a functional layer is further included between the negative electrode current collector 122 and the first negative electrode active material layer 121, for example, the functional layer includes, but is not limited to, a conductive adhesive layer. The conductive adhesive layer may include a conductive agent and a binder. This application is not particularly limited to the conductive agent, as long as it can achieve the objectives of this application, and includes, but is not limited to, at least one of a carbon-based material, a metal-based material, or a conductive polymer. The carbon-based material is at least one selected from natural graphite, artificial graphite, conductive carbon black, acetylene black, Ketjen black, or carbon fiber. The metal-based material may include, but is not limited to, metal powder and / or metal fiber. Specifically, the metal may include, but is not limited to, at least one of copper, nickel, aluminum, or silver. The conductive polymer includes, but is not limited to, at least one of polyphenylene derivatives, polyaniline, polythiophene, polyacetylene, or polypyrrole.

[0049] The present invention is not particularly limited to binders, and only those that can achieve the objectives of the present invention may be included, but are not limited to, polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymer, polyvinylpyrrolidone, polyamide, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylic acid, styrene-butadiene rubber, acrylic (esterified) styrene-butadiene rubber, epoxy resin, or nylon.

[0050] The present invention is not particularly limited to the positive electrode current collector 111, as long as it can achieve the objectives of the present invention. For example, the positive electrode current collector 111 may include aluminum foil, aluminum alloy foil, or a composite current collector. The present invention is not particularly limited to the thickness of the positive electrode current collector 111, as long as it can achieve the objectives of the present invention. For example, the thickness of the positive electrode current collector 111 is 5 μm to 20 μm, preferably 6 μm to 18 μm.

[0051] The first positive electrode active material layer 112 of this application may contain a positive electrode active material. This application is not particularly limited on the type of positive electrode active material, as long as it can achieve the objectives of this application. For example, the positive electrode active material may contain at least one of the following: lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminate, lithium iron phosphate, lithium-rich manganese-based material, lithium cobalt oxide, lithium manganese oxide, or lithium iron manganese phosphate. In this application, the positive electrode active material may further contain nonmetallic elements, for example, at least one of the following: fluorine, phosphorus, boron, chlorine, silicon, or sulfur, and these elements can further improve the stability of the positive electrode active material.

[0052] The present invention does not impose any particular limitations on the thickness of the first positive electrode active material layer 112, as long as the objective of the present invention can be achieved. For example, the thickness of the first positive electrode active material layer on one side may be 30 μm to 120 μm.

[0053] In this application, the first positive electrode active material layer 112 may be installed on one surface in the thickness direction of the positive electrode current collector 111, or on two surfaces in the thickness direction of the positive electrode current collector 111. The term "surface" here may refer to the entire area of ​​the positive electrode current collector, or to a portion of the area of ​​the positive electrode current collector. There are no particular limitations to this application, as long as the objectives of this application can be achieved.

[0054] The present invention is not particularly limited to separators and electrolytes, and those skilled in the art may select them according to their actual needs, as long as the objectives of the present invention are achieved.

[0055] There are no particular limitations on the method for adjusting the dimensions of the lithium-replenished area 123 and the lithium-unreplenished area 124, and methods of the art may be employed. For example, tape may be applied to areas on the surface of the negative electrode piece 12 that do not require lithium replenishment, and the dimensions of the tape may be adjusted according to the dimensions of the planned lithium-unreplenished area 124. Then, lithium foil is composited or rolled onto the surface of the negative electrode piece 12 to complete the lithium replenishment and then the tape is removed. In this way, a negative electrode piece 12 with lithium replenished in some areas is obtained.

[0056] The second aspect of this application provides an electronic device, including an electrochemical apparatus provided in the first aspect of this application. Since the electrochemical apparatus provided in this application has good safety performance, the electronic device provided in this application has good safety performance.

[0057] The present invention is not particularly limited to electronic devices, and may include any known electronic device used in the prior art. In some embodiments, electronic devices may include, but are not limited to, laptop computers, pen-input computers, mobile computers, e-book players, mobile phones, portable facsimile machines, portable copiers, portable printers, stereo headsets, video recorders, LCD televisions, portable cleaners, portable CD players, mini CDs, transceivers, electronic notebooks, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, automobiles, motorcycles, auxiliary bicycles, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household storage batteries or lithium-ion capacitors.

[0058] The third aspect of this application provides a method for manufacturing an electrochemical apparatus provided in the first aspect of this application. A first negative electrode active material layer 121 is provided on the surface of the negative electrode current collector 122, the negative electrode piece 12 has a first groove 13 that penetrates the first negative electrode active material layer 121, and the first negative electrode active material layer 121 has a lithium replenished region 123 and a lithium unreplenished region 124. A first positive electrode active material layer 112 is placed on the surface of the positive electrode current collector 111, and a first insulating layer 14 is attached to the first positive electrode active material layer 112. The method involves stacking a negative electrode piece 12 and a positive electrode piece 11 and winding them together as an electrode assembly 10, wherein the first negative electrode active material layer 121 faces the first positive electrode active material layer 112, and the positive projection of the first insulating layer 14 onto the negative electrode piece 12 covers the lithium-unreplenished region 124.

[0059] By employing an electrochemical apparatus manufactured by the method provided in the third aspect of this application, the risk of lithium deposition in the negative electrode piece 12 can be reduced, and the safety of the electrochemical apparatus can be improved.

[0060] In this application, the first insulating layer 14 includes at least one of a single-sided tape, a double-sided tape, or a hot-melt tape. This application is not particularly limited to the material of the first insulating layer 14, and may be at least one of polyethylene, polypropylene, or polyvinylidene fluoride, as long as it can achieve the objectives of this application.

[0061] The present invention is not particularly limited to the method of replenishing lithium, and those skilled in the art may select a method according to their actual needs, as long as it achieves the objectives of the present invention. For example, lithium foil may be rolled to a thickness of the order of microns in a drying chamber (ambient humidity <1.7%) and composite or rolling treatment may be performed on the surface of the negative electrode piece 12.

[0062] In this application, an electrochemical apparatus is obtained by packaging the electrode assembly 10, and this application is not particularly limited to the packaging process, as long as the objective of this application can be achieved.

[0063] In one embodiment of the present invention, a lithium replenishment region 123 is provided on the surface of the first negative electrode active material layer 121 using at least one of lithium foil or lithium powder. By providing the lithium replenishment region 123 as described above, the initial Coulomb efficiency of the negative electrode piece 12 can be improved, which is advantageous for improving the energy density of the electrochemical apparatus.

[0064] The embodiments of this application will be described in more detail below with reference to examples and comparative examples. Each test and evaluation will be carried out according to the following methods. Unless otherwise specified, "parts" and "%" refer to mass.

[0065] Measurement methods and equipment: Morphological measurement of the negative electrode piece: The negative electrode pieces, which have been cycled in a drying chamber (humidity <1.7%), are disassembled, washed three times with dimethyl carbonate (DMC), dried, their morphology is observed using a scanning electron microscope (SEM), SEM images are taken, and the width of the stripe portion is measured.

[0066] Morphological measurement of the cross-section of the negative electrode piece: The decomposed negative electrode fragments are polished with argon ions to prepare samples, and the cross-sectional morphology is photographed using a scanning electron microscope (SEM). The thickness of the stripe portion and the thickness of the lithium-containing compound layer on the surface of the negative electrode fragments are then measured.

[0067] High-temperature cycle acceleration measurement: Measurement environment temperature: 45±5℃ Cycle measurement flow: Charge the lithium-ion battery to full charge at the maximum rated current, let it stand for 5 minutes, discharge it to 3.0V at a constant current of 0.5C (rate), repeat the above charge-discharge flow 500 times, charge it to full charge at the maximum rated current, and repeat the cycle for 500 times. After each cycle, disassemble the lithium-ion battery and observe the lithium deposition status around the first groove.

[0068] Assessment of the degree of lithium deposition: Lithium-ion batteries that have been cycled in a drying chamber (humidity <1.7%) are disassembled, and the state of lithium deposition around the first groove is photographed and recorded. A situation where no lithium deposition is found or the lithium deposition area is <2% is defined as no lithium deposition, a situation where the lithium deposition area is between 2% and 20% is defined as slight lithium deposition, and a situation where the lithium deposition area is >20% is defined as severe lithium deposition. The fraction of the lithium deposition area is calculated based on the area of ​​the first insulating layer on the first positive electrode active material layer.

[0069] Measurement of capacity: In a 25°C environment, the battery is charged with a charging current of 0.5C (rate) until the upper voltage reaches 4.2V, then discharged with a constant current of 0.2C until the final voltage reaches 2.8V. The initial discharge capacity at 0.2C is calculated and determined as the capacity of the lithium-ion battery.

[0070] Example 1-1 <Fabrication of the negative electrode piece> The negative electrode active material is graphite, silicon oxide (SiO2). x (x=1), carboxymethylcellulose and styrene-butadiene rubber are mixed in a mass ratio of 96.7:10:1.3:1.0, and then deionized water is added as a solvent to prepare a negative electrode slurry with a solid content of 60 wt%, which is then uniformly stirred. The negative electrode slurry is uniformly applied to one surface of a copper foil negative electrode current collector with a thickness of 10 μm, and dried at 110°C to obtain a negative electrode piece with a coating thickness of 150 μm and a first negative electrode active material layer applied to one side. The above process is then repeated on the other surface of the negative electrode piece to obtain a negative electrode piece with a first negative electrode active material layer applied to both sides. After the coating is complete, the negative electrode piece is cold-pressed, tab forming, stripping, laser cleaning, etc., to obtain a negative electrode piece with a first groove in the tab. The first groove is for welding the negative electrode tab, and a negative electrode piece measuring 83.3 mm × 1494 mm is obtained, with dimensions B1 of the first groove in the tab being 20 mm and B2 being 9 mm.

[0071] Tape is applied to the area on the surface of the negative electrode piece where lithium does not need to be replenished, and the dimensions of the tape can be adjusted according to the dimensions of the planned lithium-unreplenished area, that is, A1 and A2 are adjusted by adjusting the dimensions of the tape. Then, in a drying chamber (ambient humidity <1.7%), the lithium foil is rolled to a thickness of the order of microns (2 μm), and composite and rolling treatments are performed on the surface of the prepared negative electrode piece to remove the tape on the surface of the negative electrode piece, resulting in a negative electrode piece in which lithium has not been replenished around the first groove, with dimensions A1 of the lithium-unreplenished area around the first groove being 0.5 mm and A2 being 5 mm.

[0072] <Preparation of positive electrode piece> Lithium cobalt oxide (LiCoO2), the positive electrode active material, conductive carbon black, and polyvinylidene fluoride (PVDF), the conductive agents, are mixed in a mass ratio of 97:1.4:1.6. N-methylpyrrolidone (NMP) is added as a solvent to prepare a positive electrode slurry with a solid content of 75 wt%, and the mixture is uniformly stirred. The positive electrode slurry is uniformly applied to one surface of a 10 μm thick aluminum foil positive electrode current collector and dried at 110°C to obtain a positive electrode piece with a first positive electrode active material layer thickness of 110 μm and the positive electrode active material applied to one side. Subsequently, the same procedure as above is performed, except that an empty foil area is pre-installed at one end of the positive electrode current collector for welding the positive electrode tab, to obtain a positive electrode piece with the positive electrode active material applied to both sides. After the coating is complete, the positive electrode piece is cold-pressed and then stripped to obtain and prepare a positive electrode piece measuring 81.9 mm × 1490 mm.

[0073] <Preparation of Electrolyte> In a glove box under a dry argon gas atmosphere, organic solvents ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and ethyl propionate (EP) are mixed in a mass ratio of EC:PC:DEC:EP = 3:1:3:3. Lithium hexafluorophosphate (LiPF6), a lithium salt, is added to the organic solvents, dissolved, and mixed uniformly to obtain an electrolyte with a lithium salt concentration of 1 mol / L.

[0074] <Preparation of the separator> PVDF and aluminum oxide ceramics are mixed in a mass ratio of 9:1, and deionized water is added as a solvent to prepare a slurry with a solid content of 12 wt%, which is then uniformly stirred. The slurry is then uniformly applied to one surface of a polyethylene thin film substrate with a thickness of 15 μm, and dried to obtain a separator.

[0075] <Manufacturing of lithium-ion batteries> A tab is welded to the first groove in the fabricated negative electrode piece as described above, and a positive electrode tab is welded to a pre-installed empty foil region at one end of the positive electrode piece. The positive electrode piece, the separator, and the negative electrode piece are stacked in order so that the separator is interposed between the positive electrode piece and the negative electrode piece to act as an isolation. A first insulating layer (single-sided tape, with dimensions C1 of the first insulating layer being 29 mm and C2 being 27 mm) is attached to the first positive electrode active material layer facing the first groove to which the negative electrode tab is welded, thereby positioning the lithium-unreplenished region around the first groove within the positive projection of the insulating layer onto the negative electrode piece. Then, winding is performed from the end away from the positive electrode tab to obtain the electrode assembly. The electrode assembly is placed in an aluminum packaging enclosure, dried in an 85°C vacuum oven for 12 hours to remove moisture, the prepared electrolyte is poured in, and after vacuum packaging, standing, chemical conversion (charging to 3.5V with a constant current of 0.02C, then charging to 3.9V with a constant current of 0.1C), shaping, and capacity processing, a lithium-ion battery is obtained. The designed battery capacity of this lithium-ion battery is 5000mAh.

[0076] Examples 1-2 to 1-6 Except for adjusting the dimensions A1 and A2 of the lithium-unfilled area around the first groove as shown in Table 1, this is the same as Example 1-1.

[0077] Examples 2-1 to 2-24 Except for adjusting the dimensions A1 and A2 of the lithium-unfilled area around the first groove as shown in Table 2, this is the same as Example 1-1.

[0078] Comparative Examples 1 to 4 Except for adjusting the dimensions A1 and A2 of the lithium-unfilled area around the first groove as shown in Table 2, this is the same as Example 1-1.

[0079] The relevant parameters and performance measurements for each example and comparative example are shown in Tables 1 and 2.

[0080] [Table 1]

[0081] [Table 2]

[0082] As can be seen from Examples 1-1 to 1-6, by setting the dimensions of the lithium-unfilled region around the first groove within the range of the present invention, the local capacity ratio of the negative electrode and positive electrode is large, and the negative electrode can effectively store lithium ions that have escaped from the positive electrode covered by the opposing insulating layer. This improves the problem of lithium deposition around the first groove on the negative electrode, reduces the risk of lithium deposition on the negative electrode, and improves the safety of the lithium-ion battery.

[0083] As can be seen from Examples 2-1 to 2-24 and Comparative Example 2, within the scope of the present invention, as the size of the lithium-unfilled region increases, the local capacity ratio of the negative electrode and positive electrode increases, and the negative electrode can effectively store lithium ions that have escaped from the positive electrode covered by the opposing insulating layer. This improves the problem of lithium deposition around the first groove in the negative electrode, reduces the risk of lithium deposition in the negative electrode, and improves the safety of the lithium-ion battery.

[0084] As can be seen from Comparative Example 1, when lithium was replenished around all the first grooves, a serious lithium deposition phenomenon occurred around the location of the first groove on the negative electrode piece. The reason for this is as follows: During the cycle process, the first insulating layer on the positive electrode piece corresponding to the location of the first groove on the negative electrode piece loses its binding force due to the expansion and contraction of the positive electrode active layer and immersion in the electrolyte. Surface lithium ions at the location covered by the first insulating layer move and precipitate, resulting in excessive lithium absorption and deposition on the opposing negative electrode piece, causing a serious lithium deposition phenomenon, which is detrimental to the safety of the lithium-ion battery.

[0085] As can be seen from Examples 2-1 to 2-24 and Comparative Examples 3 to 4 above, setting the dimensions of the lithium-unfilled area around the first groove to be too large significantly affects the battery capacity.

[0086] The technology provided in this application effectively reduces the risk of lithium deposition in the negative electrode piece, thereby improving the safety of lithium-ion batteries, while simultaneously improving the energy density of lithium-ion batteries and maintaining good cycle performance.

[0087] The foregoing description is merely a preferred embodiment of the present application and is not intended to limit it. Any modifications, substitutions, improvements, etc., made within the spirit and principles of the present application should be included within the scope of protection.

Claims

1. An electrochemical apparatus including an electrode assembly, wherein the electrode assembly includes a positive electrode piece and a negative electrode piece, the positive electrode piece includes a positive electrode current collector and a first positive electrode active material layer placed on the surface of the positive electrode current collector, the negative electrode piece includes a negative electrode current collector and a first negative electrode active material layer placed on the surface of the negative electrode current collector, the first negative electrode active material layer includes a lithium-replenished region and a lithium-unreplenished region, and the negative electrode piece has a first groove that penetrates the first negative electrode active material layer and exposes the surface of the negative electrode current collector. The lithium-unfilled region comprises a first edge positioned along a first direction and a second edge positioned along a second direction and connected to the first edge, wherein the first direction is the length direction of the negative electrode piece and the second direction is the width direction of the negative electrode piece. The distance between the first edge and the adjacent edge of the first groove is A. １ Let the dimension of the first groove in the second direction be B. １ Let it be mm, The positive electrode piece further includes a first insulating layer attached to the first positive electrode active material layer facing the first groove, the lithium-unreplenished region is located within the positive projection of the first insulating layer onto the negative electrode piece, and the dimensions of the first insulating layer in the second direction are C １ Let mm be the case, and 0.5 ≤ A １ ≤ C １ -B １ It is +1, Let A be the distance between the second edge and the adjacent edge of the first groove, let B be the dimension of the first groove in the first direction, and let C be the dimension of the first insulating layer in the first direction, such that 0.5 ≤ A ≤ 0.5 × (C ≤ - B ≤) + 1. Electrochemical apparatus.

2. 0.5 ≤ A １ ≤ 9, and 0.5 ≤ A ２ ≤ 9 The electrochemical apparatus according to claim 1.

3. 18 ≤ B １ ≤ 22, and 9 ≤ B ２ ≤ 13 The electrochemical apparatus according to claim 1.

4. 25 ≤ C １ ≤ 29 and 23 ≤ C ２ ≤ 27 The electrochemical apparatus according to claim 1.

5. 1.25 ≤ A １ ≤ 9, and 1.25 ≤ A ２ ≤ 9 The electrochemical apparatus according to claim 1.

6. When observed from the thickness direction of the negative electrode piece, the lithium replenishment region includes a striped portion, In the first direction, the width of the stripe portion is 0.1 mm to 2 mm, and / or In the thickness direction, the thickness of the stripe portion is 0.04 μm to 0.5 μm. The electrochemical apparatus according to claim 1.

7. The material of the lithium-replenished region includes at least one of lithium carbonate, lithium oxide, lithium nitride, or lithium fluoride. The electrochemical apparatus according to claim 1.

8. The first insulating layer includes at least one of single-sided tape, double-sided tape, or hot-melt tape. The electrochemical apparatus according to claim 1.

9. The negative electrode piece further includes a negative electrode tab that is installed in the first groove and electrically connected to the negative electrode current collector. The electrochemical apparatus according to claim 1.

10. The negative electrode piece further includes a second insulating layer installed on the negative electrode tab, wherein the positive projection of the second insulating layer onto the negative electrode piece is located within the lithium-unreplenished region. The electrochemical apparatus according to claim 9.

11. The first negative electrode active material layer contains a negative electrode active material, and the negative electrode active material contains a silicon-based material. The electrochemical apparatus according to claim 1.

12. In the second direction, the first groove does not penetrate the first negative electrode active material layer. The electrochemical apparatus according to claim 1.

13. The electrochemical apparatus includes the one described in any one of claims 1 to 12. electronic equipment.

14. A method for manufacturing an electrochemical apparatus according to any one of claims 1 to 12, The first negative electrode active material layer is provided on the surface of the negative electrode current collector, the negative electrode piece has a first groove penetrating the first negative electrode active material layer, and the first negative electrode active material layer has a lithium-replenished region and a lithium-unreplenished region. The first positive electrode active material layer is placed on the surface of the positive electrode current collector, and the first insulating layer is attached to the first positive electrode active material layer. The method involves stacking the negative electrode piece and the positive electrode piece and winding them together as the electrode assembly, wherein the first negative electrode active material layer faces the first positive electrode active material layer, and the positive projection of the first insulating layer onto the negative electrode piece covers the lithium-unreplenished region. method.

15. A lithium replenishment region is provided on the surface of the first negative electrode active material layer using at least one of lithium foil or lithium powder. The manufacturing method according to claim 14.

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