Electrochemical apparatus and electronic device
By setting the slot on the first electrode of the electrochemical device to be opposite to the gap of the diaphragm, the wettability of the electrolyte is improved, which solves the problem of balancing safety and performance in the charging and discharging process of the electrochemical device, and achieves higher charging and discharging performance and safety.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- NINGDE AMPEREX TECHNOLOGY LTD
- Filing Date
- 2025-11-28
- Publication Date
- 2026-07-16
AI Technical Summary
In the existing technology, electrochemical devices have the problem of not being able to balance safety performance and charge/discharge performance during the charging and discharging process. In particular, when the diaphragm is damaged or shrinks, it can easily lead to short circuits and explosions.
A slot is set on the first electrode of the electrochemical device, and the opening of the slot is positioned opposite to the gap of the diaphragm to improve the wettability of the electrolyte, thereby improving the charge and discharge performance. At the same time, the design of the composite part and the gap of the diaphragm reduces the risk of short circuit caused by diaphragm shrinkage.
This improved the charge-discharge performance of the electrochemical device and reduced the probability of short circuits caused by diaphragm shrinkage, achieving a balance between safety and charge-discharge performance.
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Figure CN2025138653_16072026_PF_FP_ABST
Abstract
Description
Electrochemical device and electronic device
[0001] Cross-reference to Related Applications
[0002] The present application claims priority to the Chinese patent application No. 202510018969.X, filed on January 7, 2025, and entitled "Electrochemical device and electronic device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD
[0003] Embodiments of the present application relate to the technical field of electrochemical devices, and in particular to an electrochemical device and an electronic device. BACKGROUND
[0004] The electrochemical device is applied in electronic devices such as notebook computers, tablet computers, mobile phones, wearable devices, etc. The electrochemical device provides power for the electronic device, so that the electronic device can be normally used. The charging and discharging process of the electrochemical device is a conversion process between chemical energy and electrical energy, which is accompanied by chemical reactions. In daily life, the risk of explosion and fire is extremely great when the electrochemical device is used improperly or damaged. Therefore, how to balance the safety performance and the charging and discharging performance of the electrochemical device is an important issue in the field of electrochemical devices.
[0005] SUMMARY
[0006] The technical problem solved by the embodiments of the present application is to provide an electrochemical device and an electronic device, which can effectively balance the safety performance and the charging and discharging performance of the electrochemical device.
[0007] To solve the above technical problem, one technical solution adopted by the embodiments of the present application is to provide an electrochemical device including a first electrode sheet, a second electrode sheet and a separator. The separator is arranged between the first electrode sheet and the second electrode sheet. Along the thickness direction of the first electrode sheet, the separator is arranged on both sides of the first electrode sheet. The edges of the two separators extend beyond the first electrode sheet, and the local edges of the two separators are connected to form a composite part and a receiving part. The local edges of the two separators are not connected to form a gap part. The first electrode sheet is arranged in the receiving part, and the first electrode sheet is provided with at least one first slot. At least one end of the first slot extends to the edge of the first electrode sheet to form an opening. The opening of the at least one first slot is arranged opposite to the gap part. The electrochemical device of the embodiments of the present application is provided with the first slot on the first electrode sheet, and the opening of the first slot is arranged opposite to the gap part of the separator. This is conducive to the flow of electrolyte from the gap part to the first electrode sheet, improves the wettability of the electrolyte and the active material of the first electrode sheet, and improves the charging and discharging performance of the electrochemical device.
[0008] In some embodiments, the first slot extends along a width direction of the first tab, and the gap portion is at least partially disposed in the width direction of the first tab. The first slot extends along the width direction of the first tab, so that the path of the first slot is shorter, and the electrolyte is more easily infiltrated into the first slot from the gap portion and infiltrates the active material layer in the central region of the first tab, thereby improving the infiltration effect.
[0009] In some embodiments, along the width direction of the first tab, both sides of the separator are formed with the gap portion, both ends of the first slot extend to the edge of the first tab to form an opening, and the two openings are oppositely disposed with the gap portion. The electrolyte can enter the central region of the first tab from both ends of the first slot, respectively, thereby further accelerating the infiltration of the active material on the first tab.
[0010] In some embodiments, along the length direction of the first tab, the gap portion and the composite portion are alternately distributed; along the length direction of the first tab, the length L1 of the composite portion satisfies: 0.3mm≤L1≤15mm, and / or the length L2 of the gap portion satisfies: 0.5mm≤L2≤5mm, and the length direction of the first tab is perpendicular to the width direction of the first tab. By setting the length of the composite portion of the separator within the above range, the shrinkage of the separator can be effectively inhibited, thereby improving the safety of the electrochemical device. By setting the length of the gap portion of the separator within the above range, the edge of the separator has sufficient gap for the electrolyte to enter the accommodation portion and infiltrate the first tab. In some embodiments, 1mm≤L1≤10mm, and / or 1mm≤L2≤3mm.
[0011] In some embodiments, the number N1 of openings of one end of the first slot oppositely disposed with the gap portion satisfies: N1≥10, and N1 is a positive integer. By setting at least 10 first slots such that the openings thereof are oppositely disposed with the gap portion, the electrolyte is better infiltrated with the active material layer of the first tab.
[0012] In some embodiments, the number N2 of openings of both ends of the first slot oppositely disposed with the gap portion satisfies: N2≥5, and N2 is a positive integer. By setting at least 5 first slots such that the openings of both ends thereof are oppositely disposed with the gap portion, the electrolyte can simultaneously infiltrate the central region of the first tab from both sides in the width direction of the first tab, thereby improving the infiltration effect of the first tab.
[0013] In some embodiments, along the length direction of the first electrode, the width K of the first slot satisfies: 50µm ≤ K ≤ 100µm; and / or, along the thickness direction of the first electrode, the depth H of the first slot satisfies: 10µm ≤ H ≤ 25µm. By limiting the width and depth of the first slot within the above ranges, it is beneficial for the electrolyte to flow in the first slot to wet the active material layer on the first electrode, while avoiding excessive reduction of the active material layer on the first electrode, thereby enabling the electrochemical device to have a higher energy density. In some embodiments, 60µm ≤ K ≤ 80µm; and / or, 15µm ≤ H ≤ 20µm.
[0014] In some embodiments, along the length of the first electrode, the distance L3 between two adjacent first slots satisfies: 0.8mm ≤ L3 ≤ 2mm. By setting the distance between two adjacent first slots within the above range, it helps the electrolyte entering the first slot to wet the active material layer near the first slot, so that the electrolyte fully wets the active material layer along the length of the first electrode. In some embodiments, 1mm ≤ L3 ≤ 1.5mm.
[0015] In some embodiments, the first electrode is an anode electrode and the second electrode is a cathode electrode. When the diaphragm shrinks due to heat, the anode electrode is exposed first compared to the cathode electrode. Therefore, by covering both sides of the anode electrode with a diaphragm and forming a composite region and a gap region, the probability of the diaphragm shrinking and exposing the anode electrode can be reduced, and the wetting effect of the electrolyte on the active material layer on the anode electrode can be improved.
[0016] To solve the above-mentioned technical problems, another technical solution adopted in the embodiments of this application is to provide an electronic device, including an electrochemical device.
[0017] The beneficial effects of this application embodiment are as follows: The electrochemical device of this application embodiment includes a first electrode, a second electrode, and a diaphragm. The diaphragm is disposed between the first and second electrodes. Along the thickness direction of the first electrode, diaphragms are disposed on both sides of the first electrode, and the edges of the two diaphragms are partially connected to form a composite portion. The two diaphragms are partially unconnected to form a receiving portion and a gap portion, with the gap portion located at the edge of the diaphragm. The first electrode is disposed within the receiving portion and has at least one first groove. At least one end of the first groove extends to the edge of the first electrode to form an opening, and the opening of the at least one first groove is positioned opposite to the gap portion. By providing a first groove on the first electrode and positioning the opening of the first groove opposite to the gap portion of the diaphragm, the electrochemical device of this application embodiment facilitates the flow of electrolyte from the gap portion to the first electrode, improves the wettability of the electrolyte and the active material of the first electrode, and enhances the charge-discharge performance of the electrochemical device. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the specific embodiments of this application, the accompanying drawings used in the description of the specific embodiments will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.
[0019] Figure 1 is a schematic diagram of the electrochemical device according to an embodiment of this application.
[0020] Figure 2 is a schematic diagram of the first electrode and the diaphragm of the electrochemical device according to an embodiment of this application.
[0021] Figure 3 is a cross-sectional view along AA in Figure 2.
[0022] The reference numerals in the detailed embodiments are as follows:
[0023] 100. Electrochemical device; 10. Packaging bag; 20. Battery cell assembly; 21. First electrode; 211. First slot; 2111. Opening; 22. Diaphragm; 221. Composite part; 222. Receiving part; 223. Gap part; X, width direction; Y, length direction; Z, thickness direction. Embodiments of the present invention
[0024] To facilitate understanding of this application, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed" to another element, it can be directly on the other element, or one or more intermediate elements may exist between them. The terms "upper," "lower," "inner," "outer," "vertical," "horizontal," etc., used in this specification to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0025] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.
[0026] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.
[0027] An electrochemical device comprises a packaging bag, a positive electrode, a negative electrode, and a separator. The separator is positioned between the positive and negative electrodes, which are stacked or wound together and housed inside the packaging bag, which is filled with electrolyte. The charging and discharging process of an electrochemical device involves the conversion between chemical energy and electrical energy, accompanied by chemical reactions. During the use or transportation of electronic devices, drops or collisions are inevitable. This can damage or shrink the separator, leading to direct contact and short circuit between the positive and negative electrodes, causing the electrochemical device to expand or even explode and catch fire.
[0028] To address the aforementioned issue of membrane shrinkage, existing technologies employ thermal bonding treatment on the edges of the membrane on both sides of the electrode, effectively fixing the edges of the membrane together. However, the applicant of this application has discovered that after thermal bonding treatment of the membrane edges, the bonded area inhibits the contact between the electrolyte and the electrode, resulting in poor wetting of the active material layer on the electrode and consequently deteriorating the charge-discharge performance of the electrochemical device.
[0029] Based on the above problems, this application provides an embodiment of an electrochemical device 100, which opens a groove on the active material layer of the electrode and sets the opening 2111 of the groove opposite to the uncomposite area on the separator 22, thereby allowing the electrolyte to enter the groove from the uncomposite area on the separator 22, effectively improving the wettability of the electrolyte and the active material layer of the electrode, and thus improving the charge and discharge performance of the electrochemical device 100.
[0030] In some embodiments, referring to Figures 1 to 3, the electrochemical device 100 includes a packaging bag 10 and a battery cell assembly 20. The battery cell assembly 20 is disposed inside the packaging bag 10, which is filled with an electrolyte. The electrolyte provides a site for electrochemical reactions within the battery cell assembly 20. This application does not limit the packaging bag 10 and the electrolyte; any packaging bag 10 and electrolyte from the prior art are applicable to this application.
[0031] The battery cell assembly 20 includes a first electrode 21, a second electrode, and a separator 22. The separator 22 is disposed between the first electrode 21 and the second electrode, separating them to prevent direct contact and short circuits. Along the thickness direction Z of the first electrode 21, separators 22 are disposed on both sides of the first electrode 21. The edges of the two separators 22 extend beyond the first electrode 21, and the edges of the two separators 22 are partially connected to form a composite portion 221 with a receiving portion 222. Partially unconnected portions of the two separators 22 form a gap 223. Along the thickness direction Z of the first electrode 21, a gap exists between the two separators 22 at the gap 223, allowing electrolyte to better enter the receiving portion 222 from this gap. The first electrode 21 is disposed in the receiving portion 222. The first electrode 21 has at least one first slot 211. At least one end of the first slot 211 extends to the edge of the first electrode 21 to form an opening 2111. The opening 2111 of the at least one first slot 211 is disposed opposite to the gap portion 223.
[0032] It is understandable that after the electrochemical device 100 is formed, the diaphragms 22 on both sides of the first electrode 21 will inevitably come into contact with each other. However, this contact is not necessarily the connection defined in this application. Only a connection is achieved by deliberately bonding the diaphragms 22 through thermal bonding, adhesive bonding, or other methods. For example, the composite part 221 is formed by thermal bonding of the two diaphragms 22, while the gap part 223 does not undergo such special treatment.
[0033] The electrochemical device 100 of this application embodiment provides a first slot 211 on the first electrode 21, with the opening 2111 of the first slot 211 facing the gap 223 of the diaphragm 22. This facilitates the flow of electrolyte from the gap 223 to the first electrode 21, improving the wettability of the electrolyte and the active material of the first electrode 21, and thus enhancing the charge-discharge performance of the electrochemical device 100. Furthermore, providing a thermally bonded portion 221 on the edge of the diaphragm 22 helps reduce the probability of a short circuit caused by direct contact between the first electrode 21 and the second electrode due to diaphragm 22 contraction. This balances the safety and charge-discharge performance of the electrochemical device 100.
[0034] The opposite arrangement of the opening 2111 and the gap 223 in this application means that when the first slot 211 extends along the width direction X of the first electrode 21, the projections of the opening 2111 and the gap 223 along the length direction Y of the first electrode 21 at least partially overlap; when the first slot 211 extends along the length direction Y of the first electrode 21, the projections of the opening 2111 and the gap 223 along the width direction X of the first electrode 21 at least partially overlap.
[0035] In some embodiments, the battery cell assembly 20 of this application can be a stacked battery cell assembly 20, for example, a plurality of first electrode sheets 21 and a plurality of second electrode sheets are alternately stacked in the thickness direction Z of the first electrode sheets 21, and a plurality of separators 22 are disposed between the first electrode sheets 21 and the second electrode sheets; or the battery cell assembly 20 can be a wound battery cell assembly 20, for example, after the first electrode sheets 21 and the second electrode sheets are stacked in the thickness direction Z of the first electrode sheets 21, they are wound along the length direction Y of the first electrode sheets 21 with the width direction X of the first electrode sheets 21 as the axis. It is only necessary to satisfy that the opening 2111 of the first slot 211 on the first electrode sheet 21 in the battery cell assembly 20 is opposite to the gap portion 223 of the separator 22.
[0036] In some embodiments, the first groove 211 is disposed on the active material layer of the first electrode 21. In this embodiment, the extension direction and shape of the first groove 211 are not limited. For example, the first groove 211 may extend along the length direction Y of the first electrode 21, or along the width direction X of the first electrode 21, or along a direction that forms an angle with the width direction X of the first electrode 21. The shape of the first groove 211 may be a straight line, a curve, a wavy line, a broken line, or a combination of the former, as long as the opening 2111 formed by the first groove 211 at the edge of the first electrode 21 is disposed opposite to the gap portion 223 of the diaphragm 22.
[0037] As an example, the first slot 211 extends along the width direction X of the first electrode 21, and the gap portion 223 is at least partially disposed on the width direction X of the first electrode 21. Compared to extending in other directions, the first slot 211 extends along the width direction X of the first electrode 21, making the path of the first slot 211 shorter. With at least part of the gap portion 223 disposed on the width direction X of the first electrode 21, the electrolyte can more easily enter the first slot 211 from the gap portion 223 and wet the active material layer located in the central region of the first electrode 21, thus improving the wetting effect.
[0038] In some embodiments, gaps 223 are formed on both sides of the diaphragm 22 along the width direction X of the first electrode 21, wherein each gap 223 includes at least one first gap 223a and at least one second gap 223b. Openings 2111 formed at both ends of the first groove 211 extending to the edge of the first electrode 21 include a first opening 2111a and a second opening 2111b. The first opening 2111a is opposite to the corresponding first gap 223a, and the second opening 2111b is opposite to the corresponding second gap 223b. Electrolyte can enter the central region of the first electrode 21 from both ends of the first groove 211, further accelerating the wetting of the active material on the first electrode 21. In other examples, at least one gap 223 is formed on at least one side of the diaphragm 22 along the length Y direction of the first electrode 21. The gap 223 formed on the side of the diaphragm 22 along the length Y direction of the first electrode 21 facilitates the flow of electrolyte in the receiving portion 222, further enhancing the wetting effect of the electrolyte on the active material of the first electrode 21.
[0039] In some embodiments, gap portions 223 and composite portions 221 are alternately distributed along the length direction Y of the first electrode 21. Along the length direction Y of the first electrode 21, the length L1 of the composite portion 221 satisfies: 0.3mm ≤ L1 ≤ 15mm, and / or the length L2 of the gap portion 223 satisfies: 0.5mm ≤ L2 ≤ 5mm. The length direction Y of the first electrode 21 is perpendicular to the width direction X of the first electrode 21. Setting the length of the composite portion 221 of the diaphragm 22 within the above range can effectively suppress the shrinkage of the diaphragm 22 and improve the safety of the electrochemical device 100. Setting the length of the gap portion 223 of the diaphragm 22 within the above range allows sufficient gaps at the edges of the diaphragm 22 for the electrolyte to enter the receiving portion 222 and wet the first electrode 21.
[0040] In a further embodiment, along the length Y of the first electrode 21, the length L1 of the composite portion 221 satisfies: 1mm ≤ L1 ≤ 10mm, and / or the length L2 of the gap portion 223 satisfies: 1mm ≤ L2 ≤ 3mm. By further limiting the lengths of the composite portion 221 and the gap portion 223, the number of composite portions 221 and gap portions 223 can be increased under the same length condition of the diaphragm 22, and their alternating distribution can be more uniform. This also allows the diaphragm 22 to have more gaps to allow electrolyte to enter the receiving portion 222 while effectively protecting and covering the first electrode 21.
[0041] In some embodiments, the number N1 of openings 2111 at one end of the first slot 211 opposite to the gap 223 satisfies: N1 ≥ 10, where N1 is a positive integer. As mentioned above, the shapes of the first slots 211 are diverse, and the positions of the openings 2111 formed by multiple first slots 211 at the edge of the first electrode 21 may be the same or different. In this application, it is further defined that the number of openings 2111 at one end of multiple first slots 211 opposite to the gap 223 of the diaphragm 22 is N1, where N1 is at least 10. By providing at least 10 first slots 211 with their openings 2111 opposite to the gap 223, it is helpful for the electrolyte to better wet the active material layer of the first electrode 21.
[0042] In a further embodiment, the number N2 of openings 2111 at both ends of the first slot 211 that are opposite to the gap 223 satisfies: N2 ≥ 5, where N2 is a positive integer. This application further defines the number of first slots 211 in which the openings 2111 at both ends are opposite to the gap 223 of the diaphragm 22 as N2, where N2 is at least 5. By providing at least 5 first slots 211 such that the openings 2111 at both ends are opposite to the gap 223, the electrolyte can simultaneously wet the central region of the first electrode 21 from both sides in the width direction X, improving the wetting effect on the first electrode 21.
[0043] In some embodiments, along the length Y of the first electrode 21, the width K of the first slot 211 satisfies: 50µm ≤ K ≤ 100µm; and / or, along the thickness Z of the first electrode 21, the depth H of the first slot 211 satisfies: 10µm ≤ H ≤ 25µm. By limiting the width and depth of the first slot 211 to the above ranges, it is beneficial for the electrolyte to flow in the first slot 211 to wet the active material layer on the first electrode 21, while avoiding excessive reduction of the active material layer on the first electrode 21, thereby enabling the electrochemical device 100 to have a higher energy density. In a further embodiment, 60µm ≤ K ≤ 80µm; and / or, 15µm ≤ H ≤ 20µm.
[0044] In some embodiments, along the length Y of the first electrode 21, the distance L3 between two adjacent first slots 211 satisfies: 0.8mm ≤ L3 ≤ 2mm. By setting the distance between two adjacent first slots 211 within the above range, it helps the electrolyte entering the first slot 211 to wet the active material layer near the first slot 211, so that the electrolyte can fully wet the active material layer along the length Y of the first electrode 21. In some embodiments, along the length Y of the first electrode 21, the distance L3 between two adjacent first slots 211 satisfies: 1mm ≤ L3 ≤ 1.5mm.
[0045] In some embodiments, the first electrode 21 is the anode electrode, and the second electrode is the cathode electrode. During the charging and discharging process of the electrochemical device 100, to reduce the probability of lithium plating in the cell assembly 20, the anode electrode is larger than the cathode electrode in both the length direction Y and the width direction X. When the separator 22 shrinks due to heat, the anode electrode is exposed first compared to the cathode electrode. Therefore, by covering both sides of the anode electrode with the separator 22 and forming a composite region and a gap region, the probability of the separator 22 shrinking and exposing the anode electrode can be reduced, and the wetting effect of the electrolyte on the active material layer on the anode electrode can be improved, so that the anode electrode and the cathode electrode can undergo an electrochemical reaction.
[0046] This application also provides an electronic device, which includes an electrochemical device 100 that provides electrical energy to the electronic device. The structure and function of the electrochemical device 100 can be found in any of the above embodiments, and will not be repeated here.
[0047] An embodiment of the electrochemical device 100 of this application includes a first electrode 21, a second electrode, and a diaphragm 22. The diaphragm 22 is disposed between the first electrode 21 and the second electrode. Along the thickness direction Z of the first electrode 21, diaphragms 22 are disposed on both sides of the first electrode 21, and the edges of the two diaphragms 22 are partially connected to form a composite portion 221. The two diaphragms 22 are partially not connected to form a receiving portion 222 and a gap portion 223, with the gap portion 223 located at the edge of the diaphragm 22. The first electrode 21 is disposed within the receiving portion 222 and has at least one first groove 211. At least one end of the first groove 211 extends to the edge of the first electrode 21 to form an opening 2111. The opening 2111 of the at least one first groove 211 is disposed opposite to the gap portion 223. The electrochemical device 100 of this application embodiment provides a first slot 211 on the first electrode 21, and the opening 2111 of the first slot 211 is positioned opposite to the gap 223 of the diaphragm 22. This facilitates the flow of electrolyte from the gap 223 to the first electrode 21, improves the wettability of the electrolyte to the active material of the first electrode 21, and enhances the charge and discharge performance of the electrochemical device 100.
[0048] To facilitate understanding of the technical concept and beneficial effects of this application, an experimental explanation is provided below using a lithium-ion battery as an example.
[0049] Example 1:
[0050] [Cathode Electrode Fabrication]: Aluminum foil was used as the cathode current collector. A functional coating slurry with a thickness of 1µm was uniformly coated on the surface of the aluminum foil. The functional coating slurry consisted of 89.5wt% high-resistivity material, 5wt% conductive carbon black, 5wt% lithium / sodium metal and lithium / sodium metal salt compounds, and 0.5wt% lithium carbonate, thus preparing the cathode undercoat. The lithium cobalt oxide slurry consisted of 97.3wt% LiCoO2 (LCO), 1.6wt% polyvinylidene fluoride (PVDF), and 1.1wt% conductive carbon black, and was subsequently cold-pressed to prepare the cathode electrode.
[0051] [Fabrication of the anode electrode]: A composite layer adhesive is formed by mixing 80% polyolefin and 20% carbon nanotubes. Two copper foils with a thickness of 2µm are used to form a copper foil-composite layer-copper foil composite structure negative electrode current collector through a coating process. The overall thickness H of the negative electrode current collector is 4.5µm. A 1µm thick graphite slurry is uniformly coated on the surface of the negative electrode current collector. The graphite slurry is composed of 97.7wt% artificial graphite, 1.3wt% carboxymethyl cellulose (CMC), and 1.0wt% styrene-butadiene rubber (SBR). The mixture is then cold-pressed, and 20 first grooves extending along the width direction are prepared on the anode electrode to obtain the anode electrode.
[0052] [Factory Assembly Fabrication]: Separators are placed on both sides of the anode plate, and a hot-press encapsulation process is used to heat-seal both sides of the separator in the width direction to form a composite part, and at least one gap with a length of 2mm is formed on each side edge. The number N1 of openings on one side of the first slot of the anode plate opposite to the gaps is controlled to be 1, and the number N2 of openings on both sides of the first slot opposite to the gaps is controlled to be 1. Ten anode plates wrapped with separators and nine cathode plates are alternately stacked to form a battery assembly.
[0053] [Lithium-ion battery manufacturing]: The cell assembly is placed in an outer aluminum-plastic film, and after the moisture is removed at 80°C, electrolyte is injected and the battery is sealed. After processes such as formation, degassing, and shaping, a lithium-ion battery is obtained.
[0054] Examples 2-8: Except for the number N1 of the single-sided opening and the gap of the first slot of the anode electrode being arranged opposite each other, and the number N2 of the two-sided opening and the gap of the first slot being arranged opposite each other, the other parameters are the same as those in Example 1. Please refer to Table 1 below for details.
[0055] Comparative Example 1: The difference of the lithium-ion battery is that the separator on both sides of the anode plate does not have a gap. Other parameters are the same as those in Example 1. Please refer to Table 1 below for details.
[0056] Comparative Example 2: Except that the number N1 of the single-sided opening and the gap of the first slot of the anode plate is 0, and the number N2 of the two-sided opening and the gap of the first slot is 0, the other parameters are the same as those in Example 1. See Table 1 below for details.
[0057] [Capacity Retention Test]: At 45℃, the lithium-ion battery was charged at a constant current of 0.5C to 4.45V, then charged at a constant voltage of 4.45V to a current of 0.025C. After resting for 5 minutes, it was discharged at a constant current of 0.5C to 3.0V, and the initial discharge value was recorded. Then, the lithium-ion battery was subjected to 300 cycles under the same conditions. Using the initial discharge capacity as 100%, the charge-discharge cycles were repeatedly performed until 300 cycles were reached. The final discharge capacity retention rate was recorded and calculated.
[0058] Table 1
[0059]
[0060] According to the data in the table above, setting a gap on the separator and having at least one single-sided opening of the first slot opposite to the gap is beneficial to improving the wetting effect of the electrolyte on the anode plate, thereby improving the capacity retention rate of the lithium-ion battery. Furthermore, increasing the number of single-sided openings N1 and / or the number of double-sided openings N2 of the first slot significantly improves the wetting effect of the electrolyte on the anode plate, effectively enhancing the capacity retention rate of the lithium-ion battery.
[0061] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.
Claims
1. An electrochemical device, characterized in that, include: A first electrode, a second electrode, and a diaphragm, wherein the diaphragm is disposed between the first electrode and the second electrode, and the diaphragm is disposed on both sides of the first electrode along the thickness direction of the first electrode. The edges of the two diaphragms extend beyond the first electrode, and the edges are partially connected to form a composite portion and a receiving portion. The edges of the two diaphragms are not connected to form a gap portion. The first electrode is disposed within the receiving portion. The first electrode has at least one first slot. At least one end of the first slot extends to the edge of the first electrode to form an opening. The opening of at least one first slot is disposed opposite to the gap portion.
2. The electrochemical device according to claim 1, characterized in that, The first slot extends along the width direction of the first electrode, and the gap is at least partially disposed in the width direction of the first electrode.
3. The electrochemical device according to claim 2, characterized in that, Along the width direction of the first electrode, the gap portion is formed on both sides of the diaphragm, and both ends of the first groove extend to the edge of the first electrode to form an opening, and both openings are arranged opposite to the gap portion.
4. The electrochemical device according to claim 1, characterized in that, Along the length of the first electrode, the gap portion and the composite portion are alternately distributed; Along the length direction of the first electrode, the length L1 of the composite portion satisfies: 0.3mm≤L1≤15mm, and / or the length L2 of the gap portion satisfies: 0.5mm≤L2≤5mm, and the length direction of the first electrode is perpendicular to the width direction of the first electrode.
5. The electrochemical device according to claim 4, characterized in that, 1mm≤L1≤10mm, and / or, 1mm≤L2≤3mm.
6. The electrochemical device according to claim 1, characterized in that, The number N1 of openings at one end of the first slot that are opposite to the gap portion satisfies: N1≥10, where N1 is a positive integer.
7. The electrochemical device according to claim 1, characterized in that, The number N2 of openings at both ends of the first slot that are opposite to the gap portion satisfies: N2≥5, where N2 is a positive integer.
8. The electrochemical device according to claim 1, characterized in that, Along the length of the first electrode, the groove width K of the first slot satisfies: 50um≤K≤100um; And / or, Along the thickness direction of the first electrode, the groove depth H of the first groove satisfies: 10um≤H≤25um.
9. The electrochemical device according to claim 8, characterized in that, 60um≤K≤80um; and / or, 15um≤H≤20um.
10. The electrochemical device according to claim 1, characterized in that, Along the length of the first electrode, the distance L3 between two adjacent first slots satisfies: 0.8mm≤L3≤2mm.
11. The electrochemical device according to claim 10, characterized in that, 1mm≤L3≤1.5mm.
12. The electrochemical device according to any one of claims 1-11, characterized in that, The first electrode is an anode electrode, and the second electrode is a cathode electrode.
13. An electronic device, characterized in that, Includes the electrochemical device as described in any one of claims 1-12.