Pole piece, electrochemical device, and electronic device

Abstract

The application relates to the technical field of batteries, in particular to a pole piece, an electrochemical device and electronic equipment. The pole piece comprises a current collector and an active material layer. The current collector has a coating side wall. A plurality of uniformly distributed recessed holes are arranged in the thickness direction of the current collector. The plurality of recessed holes have the same radial size and axial size. The active material layer is arranged on the coating side wall and fills the plurality of recessed holes. The active material layer is a structure made of a silicon-based material. The electrochemical device comprises the pole piece. The electronic equipment comprises the electrochemical device. The pole piece, the electrochemical device and the electronic equipment have high energy density and use safety.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to an electrode, an electrochemical device, and an electronic device. Background Technology

[0002] High-silicon electrodes (silicon content ≥50%) are key materials for improving the energy density of lithium-ion batteries due to their extremely high theoretical specific capacity (4200 mAh / g), and have become a research hotspot in recent years. However, silicon-based materials can expand in volume by 300%-400% during charge and discharge, a characteristic that severely restricts their practical application. Related research mainly focuses on "how to mitigate the impact of volume expansion on battery performance," with the optimization of current collectors being one of the core directions.

[0003] Currently, traditional current collectors have a dense, non-porous structure. They are rigid and lack buffer space, making them unable to adapt to the drastic volume expansion of high-silicon materials. This leads to easy peeling of the active material layer and the current collector interface, causing damage to the electrode structure. Utility Model Content

[0004] The main purpose of this application is to propose an electrode, an electrochemical device, and an electronic device, which aims to solve the technical problem that traditional current collectors cannot adapt to the drastic volume expansion of high-silicon materials.

[0005] To achieve the above objectives, this application proposes an electrode sheet comprising: A current collector having a coated sidewall, and along the thickness direction of the current collector, the current collector having a plurality of uniformly distributed recesses, the plurality of recesses having the same radial and axial dimensions; An active material layer is disposed on the coating sidewall and fills a plurality of the recesses. The active material layer is a structure made of silicon-based material.

[0006] In some embodiments, the radial dimension R of the recessed hole satisfies: 5um ≤ R ≤ 25um.

[0007] In some embodiments, the porosity C of the concave hole formed by the current collector satisfies: 10% ≤ C ≤ 30%.

[0008] In some embodiments, the thickness D of the current collector, the radial dimension R of the recess, and the porosity C of the current collector for opening the recess satisfy the following relationship: 5µm ≤ R ≤ D 2 *C; Wherein, D satisfies: 5um≤D≤9um, and C satisfies: 10%≤C≤30%.

[0009] In some embodiments, along the length direction of the current collector, a first non-perforated area is provided at both sides of the current collector, and the width dimension a of the first non-perforated area satisfies: 1mm≤a≤5mm; And / or, along the width direction of the current collector, a second non-perforated area is provided at both sides of the current collector, and the width dimension b of the second non-perforated area satisfies: 1mm≤b≤5mm.

[0010] In some embodiments, the distance L between two adjacent recesses satisfies: 1um ≤ L ≤ 10um.

[0011] In some embodiments, the recessed hole extends through opposite sides of the current collector along the thickness direction of the current collector.

[0012] In some embodiments, along the thickness direction of the current collector, the recess extends in a straight line from one side of the current collector to the other side of the current collector; Alternatively, along the thickness direction of the current collector, the recess extends obliquely from one side of the current collector to the other side of the current collector; Alternatively, along the thickness direction of the current collector, the recess extends along a curve from one side of the current collector to the other side.

[0013] Correspondingly, this application also proposes an electrochemical device, comprising: The electrode in any of the above embodiments includes a positive electrode and a negative electrode; A separator is disposed between the positive electrode and the negative electrode, and the separator is used to completely separate the positive electrode and the negative electrode.

[0014] Correspondingly, this application also proposes an electronic device including the electrochemical device described in the above embodiments.

[0015] Compared with the prior art, the beneficial effects of this application are: In the technical solution of this application, by creating recesses in the current collector, the structural stiffness and density of the current collector can be reduced, providing a controllable buffer space for the volume expansion of the silicon-based material. For example, during charging and discharging, the volume of the silicon-based material will expand. Because the current collector has recesses, the silicon-based material will expand into the recesses to fill them, rather than expanding arbitrarily along the length or width direction. This ensures the controllability of the silicon-based material during expansion, preventing it from detaching from the surface of the current collector during expansion. This, in turn, helps to improve the structural stability and integrity of the electrode and enhances the safety of the electrode in use.

[0016] The current collector has several evenly distributed recesses, each with the same radial and axial dimensions. In other words, the current collector has several identical recesses of the same size. This structure ensures the uniformity of the active material layer coating on the coating sidewall, avoiding uneven slurry penetration, local "excessive thickness," or "exposed foil" phenomena caused by the disordered distribution of recesses and large fluctuations in pore size. This helps to improve the electron conduction efficiency of the electrode and enhance its safety performance.

[0017] Furthermore, by creating recesses in the current collector, the wetting effect of the electrolyte on the current collector and the active material layer can be improved, promoting rapid ion transport between the electrodes, thereby improving charge and discharge efficiency and enabling fast charging. Simultaneously, it reduces the tearing effect of silicon-based materials on the SEI film due to volume expansion, improving the stability of the SEI film.

[0018] In this embodiment, the current collector has good overall continuity, ensuring the compatibility of the electrode provided in this embodiment with existing processing technologies (e.g., coating, rolling, etc.), meeting the needs of large-scale production of the electrode, and ultimately improving the cycle life, capacity retention rate and mechanical properties of the battery using the above-mentioned electrode, thus promoting the practical application of high-silicon electrode in high-energy-density batteries.

[0019] Electrochemical devices and electronic devices using the above-mentioned electrodes have high energy density and high safety in use. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of an electrode sheet provided in an embodiment of this application from a first viewing angle; Figure 2 This is a cross-sectional view of the electrode provided in an embodiment of this application from a second perspective.

[0022] Explanation of icon numbers: 10. Electrode film; 100. Current collector; 110. Coated sidewall; 120. Recessed hole; 130. First non-drilled area; 140. Second non-drilled area; 200. Active substance layer.

[0023] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0025] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0026] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or," "and / or," or "and / or" throughout the text implies three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where A and B are simultaneously satisfied. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0027] High-silicon electrodes (silicon content ≥50%) are key materials for improving the energy density of lithium-ion batteries due to their extremely high theoretical specific capacity (4200 mAh / g), and have become a research hotspot in recent years. However, silicon-based materials can expand in volume by 300%-400% during charge and discharge, a characteristic that severely restricts their practical application. Related research mainly focuses on "how to mitigate the impact of volume expansion on battery performance," with the optimization of current collectors being one of the core directions.

[0028] Currently, traditional current collectors have a dense, non-porous structure. They are rigid and lack buffer space, making them unable to adapt to the drastic volume expansion of high-silicon materials. This leads to easy peeling of the active material layer and the current collector interface, causing damage to the electrode structure.

[0029] Based on this, in order to solve the technical problem that traditional current collectors cannot adapt to the drastic volume expansion of high-silicon materials, referring to Figure 1 and Figure 2 One embodiment of this application provides an electrode 10, which includes a current collector 100 and an active material layer 200. The current collector 100 has a coated sidewall 110, and along the thickness direction of the current collector 100, a plurality of uniformly distributed recesses 120 are formed. The recesses 120 have the same radial and axial dimensions. The recesses 120 can be blind holes or through holes. The active material layer 200 is disposed on the coated sidewall 110 and fills the recesses 120. The active material layer 200 is made of silicon-based material. In this embodiment, since the active material layer 200 is made of silicon-based material, the current collector 100 is a negative electrode current collector 100, that is, the electrode 10 is a high-silicon negative electrode 10.

[0030] Specifically, in this embodiment, by creating a recess 120 on the current collector 100, the structural stiffness and density of the current collector 100 can be reduced, providing a controllable buffer space for the volume expansion of the silicon-based material. For example, during charging and discharging, the volume of the silicon-based material will expand. Since the current collector 100 is provided with a recess 120, the silicon-based material will expand into the recess 120 to fill it, and will not expand arbitrarily along the length or width direction. This ensures the controllability of the silicon-based material during expansion, preventing the silicon-based material from detaching from the surface of the current collector 100 during expansion. This is beneficial to improving the structural stability and integrity of the electrode 10 and enhancing the safety of the electrode 10 in use.

[0031] The current collector 100 has a number of recessed holes 120 evenly distributed, and the recessed holes 120 all have the same radial and axial dimensions. That is, the current collector 100 has a number of completely identical recessed holes 120 of the same size. With the above structure, the coating uniformity of the active material layer 200 on the coating sidewall 110 can be guaranteed, and the uneven penetration of the slurry, the local "excessive thickness" or "exposed foil" phenomenon caused by the disordered distribution of the recessed holes 120 and the large fluctuation of the pore size can be avoided during the coating of the active material layer 200. This is conducive to improving the electronic conduction efficiency of the electrode 10 and improving the safety performance of the electrode 10.

[0032] Furthermore, by creating recesses 120 in the current collector 100, the wetting effect of the electrolyte on the current collector 100 and the active material layer 200 can be improved, promoting rapid ion transport between the electrodes 10, thereby improving charging and discharging efficiency and achieving fast charging functionality. Simultaneously, it reduces the tearing effect of silicon-based materials on the SEI film due to volume expansion, improving the stability of the SEI film.

[0033] In this embodiment, the current collector 100 has good overall continuity, ensuring the compatibility of the electrode 10 provided in this embodiment with existing processing technologies (e.g., coating, rolling, etc.), meeting the needs of large-scale production of the electrode 10, and ultimately improving the cycle life, capacity retention rate and mechanical properties of the battery using the above-mentioned electrode 10, thus promoting the practical application of high-silicon electrode 10 in high-energy-density batteries.

[0034] In some embodiments, refer to Figure 1 and Figure 2 The radial dimension R of the recess 120 satisfies: 5um ≤ R ≤ 25um. For example, the value of R can be 5um, 6um, 7um, 8um, 9um, 10um, 11um, 12um, 13um, 14um, 15um, 16um, 17um, 18um, 19um, 20um, 21um, 22um, 23um, 24um, 25um, etc. One possible implementation is to use laser drilling to create the recess 120 on the current collector 100. Alternatively, another possible implementation is to use a mold to create the recess 120 on the current collector 100 during its fabrication, thus eliminating the need for secondary processing.

[0035] Specifically, in this embodiment, the radial dimension of the recess 120 is set within the aforementioned range. Firstly, this ensures that the aperture of the recess 120 is large enough to accommodate the expanded silicon-based active material layer 200, preventing the silicon-based active material layer 200 from expanding along its width or length after expansion. This improves the bonding strength between the silicon-based active material layer 200 and the current collector 100, ensuring the structural stability of the electrode 10 during charging and discharging, and enhancing the safety performance of the electrode 10. Secondly, this ensures the structural strength and mechanical properties of the current collector 100 itself, preventing the structure of the current collector 100 from becoming weak due to excessively large recesses 120, thus extending the service life of the electrode 10. Thirdly, this reduces the difficulty of drilling holes in the current collector 100, improves the drilling efficiency, and ensures the compatibility between the current collector 100 and existing processing equipment.

[0036] In some embodiments, the porosity C of the recessed holes 120 in the current collector 100 satisfies: 10% ≤ C ≤ 30%. For example, the value of C can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, etc.

[0037] Specifically, in this embodiment, the porosity of the recessed holes 120 in the current collector 100 is at least 10%, which ensures that the current collector 100 provides sufficient buffer space. During the charging and discharging process, when the silicon-based active material layer 200 expands, it can fill the recessed holes 120 as much as possible. This not only improves the bonding strength between the active material layer 200 and the current collector 100, ensuring the structural stability and reliability of the electrode 10, but also prevents the volume-expanding active material layer 200 from repeatedly tearing the formed SEI film, avoiding the consumption of a large amount of electrolyte and lithium source during the continuous cracking and regeneration process of the SEI film. This is beneficial to improving the cycle life of the battery using the above-mentioned electrode 10 and extending the battery's service life.

[0038] The porosity of the recessed holes 120 in the current collector 100 shall not exceed 30%, ensuring that the current collector 100 has high mechanical properties and structural strength, preventing it from being easily damaged after impact, and ensuring that the current collector 100 has high impact resistance. Moreover, if the porosity of the recessed holes 120 in the current collector 100 is too high, it will not only affect the electron conduction efficiency of the current collector 100, leading to an increase in the resistance of the current collector 100, but it will also make the current collector 100 incompatible with existing rolling processes. When the current collector 100 is processed using traditional rolling processes, it will cause the current collector 100 to deform, which is not conducive to ensuring the processing and safety of the electrode 10.

[0039] In some embodiments, the thickness D of the current collector 100, the radial dimension R of the recess 120, and the porosity C of the current collector 100 with the recess 120 satisfy the following relationship: 5µm ≤ R ≤ D 2 *C. Wherein, D satisfies: 5um ≤ D ≤ 9um, and C satisfies: 10% ≤ C ≤ 30%. For example, the value of D can be 5um, 6um, 7um, 8um, 9um, etc. The value of C can be 10%, 15%, 20%, 25%, 30%, etc.

[0040] Specifically, in this embodiment, the above formula establishes a direct relationship between the thickness of the current collector 100, the radial dimension of the recess 120, and the porosity of the recess 120 in the current collector 100. When the thickness of the current collector 100 or the porosity of the recess 120 changes, the above formula can adaptively adjust the radial dimension of the recess 120 to ensure that the size of the recess 120 on the current collector 100 is appropriate. This ensures that the recess 120 can provide sufficient buffer space while also ensuring the structural strength and mechanical properties of the current collector 100, ultimately improving the safety of the electrode 10 and extending its service life.

[0041] In some embodiments, refer to Figure 1Along the length of the current collector 100, a first non-perforated area 130 is provided at each of its two side edges. The width 'a' of the first non-perforated area 130 satisfies the condition: 1mm ≤ a ≤ 5mm. That is, along the length of the current collector 100, the current collector 100 has two first non-perforated areas 130. For example, the value of 'a' can be 1mm, 2mm, 3mm, 4mm, 5mm, etc.

[0042] And / or, along the width direction of the current collector 100, a second non-perforated area 140 is provided at each of the two edge positions of the current collector 100, and the width dimension b of the second non-perforated area 140 satisfies: 1mm ≤ b ≤ 5mm. That is, along the width direction of the current collector 100, the current collector 100 has two second non-perforated areas 140. For example, the value of b can be 1mm, 2mm, 3mm, 4mm, 5mm, etc.

[0043] Specifically, in this embodiment, the so-called "first non-drilled area 130" and "second non-drilled area 140" refer to areas where no recessed holes 120 are provided, i.e., the first non-drilled area 130 and the second non-drilled area 140 are blank areas. This helps to ensure the structural strength of the current collector 100 at the edge position, prevent the current collector 100 from warping at the edge position, improve the flatness of the current collector 100 at the edge position, and maintain the overall thickness consistency of the electrode sheet 10.

[0044] The dimensions of the first non-drilled area 130 and the second non-drilled area 140 are set within the above-mentioned range. On the one hand, this avoids the first non-drilled area 130 and the second non-drilled area 140 having large blank spaces, which could easily cause uneven distribution of openings on the current collector 100 and affect the uniformity of the coating of the active material layer 200 on the current collector 100. On the other hand, it avoids the first non-drilled area 130 and the second non-drilled area 140 having too small blank spaces, which could easily cause the edges of the current collector 100 to lift up and affect the conductivity of the current collector 100.

[0045] In some embodiments, refer to Figure 1 The distance L between two adjacent recesses 120 satisfies: 1um ≤ L ≤ 10um. For example, the value of L can be 1um, 2um, 3um, 4um, 5um, 6um, 7um, 8um, 9um, 10um, etc. That is, the current collector 100 contains 1000-10000 of the above-mentioned recesses 120 per square centimeter.

[0046] Specifically, in this embodiment, the distance between two adjacent recesses 120 is set within the aforementioned range. On the one hand, this prevents two adjacent recesses 120 from being too densely packed, which would reduce the structural strength and mechanical properties of the current collector 100, making it prone to wrinkling and warping during the rolling process, which would be detrimental to the flatness and conductivity of the electrode 10. On the other hand, this prevents two adjacent recesses 120 from being too far apart, which would prevent the current collector 100 from effectively providing sufficient buffer space, so that the expanded silicon-based active material layer 200 cannot be well filled into the recesses 120, which would be detrimental to the bonding strength between the active material layer 200 and the current collector 100, as well as the safety of the electrode 10 in use.

[0047] In some embodiments, refer to Figure 2 Along the thickness direction of the current collector 100, the concave hole 120 penetrates the opposite sides of the current collector 100.

[0048] Specifically, in this embodiment, by setting the concave hole 120 as a through hole structure, it is beneficial to coat the active material layer 200 on both sides of the current collector 100, thereby achieving double-sided coating of the active material layer 200 on the current collector 100. This is beneficial to increase the energy density and capacitance of the electrode 10, improve the ion transport efficiency in the electrode 10, and prevent the electrode 10 from easily undergoing lithium plating.

[0049] Furthermore, opening a recessed hole 120 along the thickness direction of the current collector 100 helps to reduce the difficulty of opening the recessed hole 120 and improve the efficiency of opening the recessed hole 120.

[0050] In some embodiments, refer to Figure 2 Along the thickness direction of the current collector 100, the recess 120 extends in a straight line from one side of the current collector 100 to the other side of the current collector 100.

[0051] Specifically, in this embodiment, a linear drilling method is adopted, which is simple to process and has a high yield. The drilling equipment can be perpendicular to the surface of the current collector 100. The accuracy requirements of the drilling equipment are low. The drilling operation on the current collector 100 can be realized using traditional drilling equipment, which is economical, efficient and easy to achieve mass production.

[0052] Alternatively, in some embodiments, the recess 120 extends obliquely from one side of the current collector 100 to the other side of the current collector 100 along the thickness direction of the current collector 100. Alternatively, in some embodiments, the recess 120 extends along a curve from one side of the current collector 100 to the other side of the current collector 100 along the thickness direction of the current collector 100.

[0053] Specifically, in this embodiment, using an inclined drilling method or a curved drilling method helps to increase the filling path of the expanded active material layer 200 in the recess 120, ensuring that the recess 120 can provide sufficient buffer space and improve the bonding strength between the active material layer 200 and the current collector 100.

[0054] Referring to Tables 1 and 2, the following test experiments were conducted using several sets of comparative examples and embodiments:

[0055] Table 1

[0056] Table 2 As can be seen from Tables 1 and 2, each embodiment exhibits a good balance: tensile strength (255-367 MPa) is related to pore structure, with embodiment 5 (C=11%) having the highest strength (367 MPa) due to its lower porosity; roll forming yield (62.4-79.36%) is positively correlated with mechanical strength, with embodiments having higher strength showing better processing performance; electrolyte contact angle (10°-32°) directly reflects the improvement of wettability by micropores, with embodiments with large pore size and high porosity (such as embodiment 4, R=5 μm, C=25%) having the smallest contact angle (10°) and the best wettability; most importantly, in terms of electrochemical performance, the capacity retention rate after 500 cycles (76.5%-90.2%) confirms the effectiveness of the micropore design in buffering silicon expansion, with embodiment 9 (D=8, R=12, C=23%) exhibiting the best cycle stability (90.2%).

[0057] The comparative examples, on the other hand, verified the boundary constraint effect of the formula from the opposite perspective: Comparative Example 1 (R=4μm<5), due to its small pore size, although possessing high mechanical strength (378MPa), suffered from poor electrolyte wettability (contact angle 20°), resulting in a cycle performance (79.3%) inferior to all other examples; Comparative Example 2 (R=30μm>25 and far exceeding its D²·C value of 9), due to its excessively large pore size, severely compromised structural integrity, leading to a sharp deterioration in mechanical strength (185MPa) and roll forming yield (42.6%), and the worst cycle performance (76.1%). These data consistently demonstrate that deviation from the core formula will result in fatal defects in the current collector in one of the mechanical, process, or electrochemical aspects. This application, through parameter correlation defined by the formula, successfully achieved synergistic optimization of high strength, high process yield, and long cycle life for high-silicon anode current collectors.

[0058] Tensile testing refers to cutting the current collector into standard dumbbell-shaped specimens, conducting the test on a universal testing machine, and recording its tensile strength.

[0059] The yield rate of rolled products refers to the percentage of electrode sheets that are deemed good in the rolling process, without defects such as curling, breakage, or powder shedding.

[0060] Electrolyte contact angle refers to the angle of contact when a small droplet of electrolyte (typically 1-5 microliters) is smoothly dropped onto the surface of a current collector using a microsyringe. The shape of the droplet is instantly captured using a high-speed camera equipped with a high-resolution lens and backlight. Software automatically fits the droplet baseline and gas-liquid interface profile to calculate the contact angle value.

[0061] Cycle capacity retention refers to the following: under normal temperature conditions, the battery is charged to 0.05C at a constant current of 2.5C and 4.55V, allowed to stand for 5 minutes, discharged to 3.0V at 0.7C, allowed to stand for 5 minutes, and this charge-discharge cycle is repeated 500 times.

[0062] Correspondingly, another embodiment of this application also provides an electrochemical device, which includes the electrode 10 in any of the above embodiments, the electrode 10 including a positive electrode 10 and a negative electrode 10. The electrochemical device also includes a separator disposed between the positive electrode 10 and the negative electrode 10, the separator being used to completely separate the positive electrode 10 and the negative electrode 10, preventing the positive electrode 10 and the negative electrode 10 from directly contacting each other and causing an internal short circuit in the electrochemical device.

[0063] Exemplarily, the electrochemical device can be a wound cell or a stacked cell. Alternatively, the electrochemical device includes any apparatus in which an electrochemical reaction occurs to interconvert chemical energy into electrical energy, with specific, non-limiting examples including all types of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In particular, the electrochemical device is a lithium secondary battery, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, or lithium-ion polymer secondary batteries.

[0064] Specifically, in this embodiment, the application of the silicon-based electrode 10 in the above embodiments can significantly improve the energy density of the electrochemical device and ensure the safe performance of the electrochemical device.

[0065] Correspondingly, another embodiment of this application also provides an electronic device, which includes the electrochemical device in the above embodiments. Exemplarily, the electronic device of this application is not particularly limited, and it can be any electronic device known in the prior art. The use of the electrochemical device of this application is not particularly limited, and it can be used in any electronic device known in the prior art. According to some embodiments, the electronic device includes, but is not limited to, mobile phones, smartphones, laptops, tablets, wearable devices, smartwatches, smart bracelets, smart glasses, power banks, televisions, game consoles, game controllers, digital cameras, smart speakers, headphones, keyboards, mice, monitors, drones, audio equipment, home appliances, toys, power tools, automobiles, motorcycles, electric bicycles, bicycles, robots, robot dogs, industrial robots, android robots, etc.

[0066] Specifically, in this embodiment, the electronic device using the above-mentioned electrochemical device has a high energy density, which can improve the standby time of the electrochemical device.

[0067] Thanks to the improvements to the electrode 10 described above, the electrochemical device and electronic device of this embodiment have the same technical effects as the electrode 10 described above, which will not be repeated here.

[0068] It should be noted that other undisclosed contents of the electrode 10, electrochemical device and electronic device provided in this application can be found in the prior art, and will not be repeated here.

[0069] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural transformations made based on the content of the specification and drawings of this application under the concept of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. An electrode, characterized in that, include: A current collector having a coated sidewall, and along the thickness direction of the current collector, the current collector having a plurality of uniformly distributed recesses, the plurality of recesses having the same radial and axial dimensions; An active material layer is disposed on the coating sidewall and fills the plurality of the recesses.

2. The electrode sheet according to claim 1, characterized in that, The radial dimension R of the concave hole satisfies: 5um ≤ R ≤ 25um.

3. The electrode sheet according to claim 1, characterized in that, The porosity C of the concave hole in the current collector satisfies: 10% ≤ C ≤ 30%.

4. The electrode sheet according to claim 1, characterized in that, The thickness D of the current collector, the radial dimension R of the recess, and the porosity C of the current collector for opening the recess satisfy the following relationship: 5µm ≤ R ≤ D 2 *C; Wherein, D satisfies: 5um≤D≤9um, and C satisfies: 10%≤C≤30%.

5. The electrode sheet according to claim 1, characterized in that, Along the length of the current collector, a first non-perforated area is provided at both sides of the current collector, and the width dimension a of the first non-perforated area satisfies: 1mm≤a≤5mm; And / or, along the width direction of the current collector, a second non-perforated area is provided at both sides of the current collector, and the width dimension b of the second non-perforated area satisfies: 1mm≤b≤5mm.

6. The electrode sheet according to claim 1, characterized in that, The distance L between two adjacent recesses satisfies: 1um ≤ L ≤ 10um.

7. The electrode sheet according to claim 1, characterized in that, Along the thickness direction of the current collector, the concave hole penetrates through the opposite sides of the current collector.

8. The electrode sheet according to claim 7, characterized in that, Along the thickness direction of the current collector, the recessed hole extends in a straight line from one side of the current collector to the other side of the current collector; Alternatively, along the thickness direction of the current collector, the recess extends obliquely from one side of the current collector to the other side of the current collector; Alternatively, along the thickness direction of the current collector, the recess extends along a curve from one side of the current collector to the other side.

9. The electrode sheet according to claim 1, characterized in that, The active material layer is a structure made of silicon-based material.

10. An electrochemical device, characterized in that, include: The electrode sheet according to any one of claims 1 to 9, wherein the electrode sheet comprises a positive electrode sheet and a negative electrode sheet; A separator is disposed between the positive electrode and the negative electrode, and the separator is used to completely separate the positive electrode and the negative electrode.

11. An electronic device, characterized in that, include: The electrochemical device as claimed in claim 10.

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