Embossed electrode sheet containing a coded pattern, method of manufacture, method of quality traceability, computer device and readable storage medium

Abstract

The application provides a patterned electrode sheet containing a coding pattern, a preparation method, a quality tracing method, a computer device and a readable storage medium. The current collector in the patterned electrode sheet containing the coding pattern is provided with a plurality of active areas and non-active areas. The electrode active material layer is located in the active area, and the surface of the electrode active material layer is provided with a first embossed section. The first embossed section includes a plurality of first embossed units. The surface of the non-active area is provided with a second embossed section. The second embossed section includes a plurality of second embossed units. The second embossed units have at least two different depths. The center distance between adjacent two second embossed units in the second embossed section has at least three different intervals. By arranging the embossed sections with different functions on the same electrode sheet, the quality detection efficiency and tracing accuracy can be effectively improved while improving the quality of the electrode sheet, and the influence on the battery performance is reduced.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, specifically relating to an embossed electrode sheet with a coded pattern, a preparation method, a quality traceability method, a computer device, and a readable storage medium. Background Technology

[0002] In the manufacturing process of lithium-ion batteries, electrode sheets are the core components that make up the battery cell. For a single high-capacity battery cell, it is usually made from electrode sheets tens to hundreds of meters long through winding or stacking processes. Therefore, the batch consistency of electrode sheet quality directly affects the yield of the battery cell. When a battery cell exhibits performance abnormalities during the formation, capacity testing, or end-use stages, it is necessary to quickly trace back to the specific electrode segment, coating machine number, and rolling batch, etc., to narrow down the scope of control for abnormal products and reduce the cost losses caused by rework.

[0003] Based on this, the prior art discloses the use of the following technical solutions to solve the above problems, as detailed below: (1) Laser marking / inkjet printing traceability: A technical solution discloses a lithium battery marking traceability method, specifically including: before the electrode strip is slit, a QR code pattern is etched on the electrode strip by a first laser component, and a line pattern is etched on the electrode strip by a second laser component, wherein the line pattern is used to identify the defect of the electrode strip; then, during slit, the line pattern is identified by a visual sensor to perform skip slit. Although the above technical solution can quickly identify defective electrode strips, it requires the addition of an independent laser component and optical path system, resulting in high equipment cost; at the same time, laser etching may damage the current collector or active material layer, thereby producing burrs or heat-affected zones.

[0004] (2) Electrode Information Traceability System: Another technical solution discloses a traceability method for lithium-ion batteries, which achieves electrode-level traceability by obtaining a first identifier and establishing a binding relationship. However, the above technical solution mainly relies on external identifiers (such as RFID tags and inkjet markings) rather than the structural characteristics of the electrode itself, and the external identifiers may fall off, become contaminated, or be covered during the production process.

[0005] In addition, in order to improve the overall performance of the battery, existing technologies have disclosed technical solutions for setting embossing on the surface of the electrode sheet. However, most of these solutions are for purposes such as enhancing the adhesion between the electrode sheet and the separator, improving the electrolyte wetting effect, relieving the expansion stress of the electrode sheet, improving the consistency of interface contact, or packaging anti-counterfeiting, and do not have the function of electrode sheet positioning and traceability.

[0006] It can be seen that in the current electrode sheet manufacturing process, functional embossing technology and quality traceability methods belong to two completely independent technical systems. The former is realized by embossing rollers / embossing devices, while the latter is realized by external marking systems such as laser marking / inkjet marking / RFID. The two occupy independent process and equipment resources, and have inherent shortcomings in terms of traceability accuracy and structural integration. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide an embossed electrode sheet with a coded pattern, a preparation method, a quality traceability method, a computer device, and a readable storage medium. By setting embossed sections with different functions on the same electrode sheet, the present invention improves the quality of the electrode sheet while effectively increasing quality inspection efficiency and traceability accuracy, and reducing the impact on battery performance.

[0008] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides an embossed electrode sheet containing a coded pattern, comprising a current collector and an electrode active material layer disposed on at least one side of the current collector, wherein the current collector is provided with a plurality of active regions and inactive regions, and the active regions and the inactive regions are alternately distributed along the length direction of the electrode sheet. The electrode active material layer is located in the active region, and a first embossing section is provided on the surface of the electrode active material layer, the first embossing section including a plurality of first embossing units; The surface of the inactive area is provided with a second embossed section, the second embossed section includes a plurality of second embossed units, and the second embossed units have at least two different depths, and the center distance between two adjacent second embossed units in the second embossed section has at least three different spacings.

[0009] This invention aims to improve the electrochemical performance of batteries by setting functional first embossed sections (such as liquid-conducting grooves, expansion buffer protrusions, etc.) in the active areas of the electrode sheet; and to set second embossed sections with manufacturing information in the inactive areas of the electrode sheet (such as blank areas at the root of the tab, the end or tail section of the single-sided area, etc.) to facilitate the quality traceability of the electrode sheet, thereby achieving accurate identification, precise positioning and effective traceability of defective electrode sheets, overcoming the shortcomings of the prior art, and improving the production quality and efficiency of electrode sheets, as detailed below: (1) High traceability accuracy: By directly forming the second embossed section with manufacturing information on the surface of the electrode sheet, the external markings are easily detached, covered or counterfeited, thus realizing physical traceability at the electrode sheet level.

[0010] (2) No additional process: The second embossing section with manufacturing information and the functional first embossing section can be formed in the same rolling process without adding extra equipment or process steps, which simplifies the production process and reduces production costs.

[0011] (3) Does not affect battery performance: The second embossing section with manufacturing information is set in the non-active area of ​​the electrode sheet to avoid damage to the active material of the electrode, so it will not have any adverse effect on the electrochemical performance of the battery.

[0012] (4) Sufficient information capacity: By encoding information through a multi-dimensional combination of the "depth level" (at least two different depths) and the "center distance combination" (at least three different spacings) of the second embossing unit, the information capacity can be further expanded (extendable to more than 128 bits) to meet the quality traceability requirements of large-scale production.

[0013] Preferably, the projected area of ​​the second embossing unit in the plane containing the current collector corresponds to an equivalent circle diameter of 20μm to 200μm, more preferably 50μm to 150μm. For example, the corresponding equivalent circle diameter can be 20μm, 50μm, 80μm, 100μm, 120μm, 150μm, 180μm, or 200μm, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0014] For example, the shape of the second embossing unit includes, but is not limited to, at least one of a circle, a square, or a cross.

[0015] Preferably, the depth of the second embossing unit is 5μm to 20μm, more preferably 8μm to 18μm, for example, it can be 5μm, 8μm, 10μm, 12μm, 15μm, 18μm or 20μm, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0016] This invention adjusts the planar dimensions and depth of the second embossing unit to a suitable range, thereby controlling the material to be indistinguishable to the human eye but readable by a CCD vision system under specific angle lighting, without affecting the appearance of the electrode sheet.

[0017] Preferably, the center distance between two adjacent second embossing units is 100μm to 1000μm, more preferably 150μm to 700μm, for example, it can be 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm or 1000μm, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0018] Preferably, at least two calibration embossing marks are provided at the boundary of the second embossing unit.

[0019] Preferably, the size of the embossed mark for calibration is 300μm to 500μm, for example, it can be 300μm, 320μm, 350μm, 380μm, 400μm, 420μm, 450μm, 480μm or 500μm, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0020] Preferably, the depth of the calibration embossing mark is the median value of the depths of different second embossing units.

[0021] Preferably, the embossed mark for calibration is at least one of a cross, a circle, or a polygon.

[0022] This invention facilitates rapid recognition by CCD vision systems by adjusting the size, depth, and shape of the embossed markings used for calibration, ensuring compensation for reading angle deviations, and calibrating the coordinate system.

[0023] Preferably, the depth of the first embossing unit is 5% to 40% of the thickness of the electrode active material layer, for example, it can be 5%, 8%, 10%, 15%, 20%, 25%, 30%, 35% or 40%, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] Preferably, the ratio of the depth of the first embossing unit to the maximum depth of the second embossing unit is 1:(0.3~3), more preferably 1:(0.5~2), for example, it can be 1:0.3, 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8 or 1:3, etc., not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0025] By controlling the above-mentioned proportional relationship, the present invention can make the forming accuracy and stress distribution of the two embossing patterns more uniform in the same rolling process, thereby further improving the coding reading effect and electrode sheet consistency.

[0026] In this invention, the shape of the first embossing unit includes, but is not limited to, at least one of grooves, protrusions or trenches, so that it can be used for electrolyte flow, storage or buffering volume expansion.

[0027] In this invention, the current collector includes a positive current collector or a negative current collector.

[0028] As an example, the positive current collector includes, but is not limited to, aluminum foil, and the negative current collector includes, but is not limited to, copper foil; the present invention does not limit this.

[0029] In this invention, the thickness of the current collector is 8μm to 20μm, for example, it can be 8μm, 10μm, 12μm, 15μm, 18μm or 20μm, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] In a second aspect, the present invention provides a method for preparing an embossed electrode sheet containing a coded pattern according to the first aspect, the method comprising the following steps: An electrode sheet precursor containing an electrode active material layer was prepared. The electrode precursor is embossed once using a combined embossing roller to obtain the embossed electrode with the coded pattern. The combined embossing roller is provided with alternating first embossing portions and second embossing portions along the axial direction. The first embossing portion is used to form a first embossing segment in the active region of the electrode sheet precursor, and the second embossing portion is used to form a second embossing segment in the inactive region of the electrode sheet precursor.

[0031] Thirdly, the present invention provides a method for tracing the quality of electrode sheets, the method comprising the following steps: The embossed electrode sheet containing the coded pattern as described in the first aspect is encoded to generate a bound electrode sheet traceability code, and the electrode sheet traceability code is uploaded to the target system; wherein, "bound" means that the electrode sheet traceability code is bound to the information of the electrode sheet; During the preparation of the electrode sheet, image recognition technology is used to identify the coded pattern and the identification result is converted into binary code; The binary code is decoded to obtain the electrode traceability code, and the electrode associated with the electrode traceability code is traced to locate the position of the electrode.

[0032] Preferably, during the information encoding process, nine-bit binary numbers are used to encode the depth of the second embossing unit and the center distance between two adjacent second embossing units.

[0033] In this invention, the rules for information encoding may, exemplarily, include: (A) Depth Dimension: Each second embossing unit within the same second embossing segment has at least two different preset depths. For example, the first depth level d1 = 5μm~10μm (which can represent binary "0"), and the second depth level d2 = 15μm~20μm (which can represent binary "1"). When three depth levels are used, ternary or higher base encoding can be achieved.

[0034] (B) Spacing dimension: The center distance between two adjacent second embossed units has at least three different preset spacings. For example, the first spacing s1 = 100μm~200μm (can represent "00"), the second spacing s2 = 200μm~400μm (can represent "01"), the third spacing s3 = 400μm~600μm (can represent "10"), and the fourth spacing s4 = 600μm~1000μm (can represent "11").

[0035] Preferably, the information of the electrode sheet includes at least one of the following: electrode sheet production batch number, coating machine number, rolling parameter group number, slitting date, or roll number.

[0036] In this invention, the target system may be, for example, an MES system.

[0037] Preferably, the image recognition technology device includes a CCD vision system that can recognize the coded pattern under specific angle lighting conditions.

[0038] Fourthly, the present invention provides a computer device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the electrode sheet quality traceability method according to the third aspect.

[0039] In this invention, the computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input device connected via a system bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage medium. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be a liquid crystal display (LCD) or an e-ink display. The input device can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the device's casing, or an external keyboard, touchpad, or mouse.

[0040] Fifthly, the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the electrode sheet quality traceability method according to the third aspect.

[0041] In this invention, the computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0042] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0043] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a dual-functional embossed electrode sheet. By setting a functional first embossed section (such as a liquid-conducting groove, expansion buffer protrusion, etc.) in the active region of the electrode sheet, it aims to improve the electrochemical performance of the battery. Furthermore, by setting a second embossed section containing manufacturing information in the inactive region of the electrode sheet (such as the blank area at the root of the tab, the end or tail section of the single-sided area, etc.), it facilitates quality traceability of the electrode sheet, thereby achieving accurate identification, precise location, and effective traceability of defective electrode sheets. This overcomes the shortcomings of existing technologies and improves the production quality and efficiency of electrode sheets, as detailed below: (1) High traceability accuracy: By directly forming the second embossed section with manufacturing information on the surface of the electrode sheet, the external markings are easily detached, covered or counterfeited, thus realizing physical traceability at the electrode sheet level.

[0044] (2) No additional process: The second embossing section with manufacturing information and the functional first embossing section can be formed in the same rolling process without adding extra equipment or process steps, which simplifies the production process and reduces production costs.

[0045] (3) Does not affect battery performance: The second embossing section with manufacturing information is set in the non-active area of ​​the electrode sheet to avoid damage to the active material of the electrode, so it will not have any adverse effect on the electrochemical performance of the battery.

[0046] (4) Sufficient information capacity: By encoding information through a multi-dimensional combination of the "depth level" (at least two different depths) and the "center distance combination" (at least three different spacings) of the second embossing unit, the information capacity can be further expanded (extendable to more than 128 bits) to meet the quality traceability requirements of large-scale production. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the structure of the embossed positive electrode sheet with a coded pattern provided in Embodiment 1 of the present invention.

[0048] The attached figures are labeled as follows: 1-aluminum foil current collector, 2-positive electrode active material layer, 3-first embossed section, 4-inactive region, 5-second embossed section, 6-calibration embossed mark. Detailed Implementation

[0049] The technical solution of the present invention will be further described below with reference to specific embodiments and accompanying drawings. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be considered as specific limitations thereof.

[0050] Example 1 like Figure 1 As shown, this embodiment provides an embossed positive electrode sheet with a coded pattern, which includes an aluminum foil current collector 1 (13 μm thick) and a positive electrode active material layer 2 (120 μm thick on one side) disposed on one side of the aluminum foil current collector 1. The aluminum foil current collector 1 is provided with a plurality of active regions and inactive regions 4, which are alternately distributed along the length of the electrode sheet.

[0051] The positive electrode active material layer 2 comprises NCM811, conductive agent Super P, and binder polyvinylidene fluoride in a mass ratio of 8:1:1, and is located in the active region. A first embossed section 3 is formed on the surface of the positive electrode active material layer 2. The first embossed section 3 includes multiple parallel stripe-shaped grooves with a depth of 25 μm. The width of the first embossed section 3 is 200 μm, and its length is 600 μm.

[0052] The surface of the blank, inactive area (5mm × 5mm) at the root of the electrode is provided with a second embossed section 5. The second embossed section 5 includes multiple second embossed units, and each of the four corners of the second embossed unit is provided with a cross-shaped calibration embossed mark 6. The specific encoding parameters are: two depth levels (d1=8μm represents "0", d2=18μm represents "1") + three spacings (s1=150μm represents binary "00", s2=300μm represents binary "01", s3=500μm represents binary "10"). The projected area of ​​the second embossed unit in the plane of the aluminum foil current collector 1 corresponds to an equivalent circle diameter of 100μm, and the total information capacity is 96 bits. The size of the calibration mark 6 is 400μm, and the depth is the midpoint of the two depth levels, 13μm.

[0053] This embodiment also provides the above-mentioned embossed positive electrode sheet with coded pattern and a method for quality traceability of the positive electrode sheet in the manufacturing process of lithium-ion batteries, which includes the following steps: (1) A positive electrode active material layer is formed on the surface of the aluminum foil current collector by wet coating, and active coating area and inactive area are divided on the positive electrode sheet.

[0054] (2) A combined embossing roller is provided, wherein a first embossing portion (having a first raised pattern) and a second embossing portion (having a second raised pattern for coding, specifically including raised units of different heights and raised marks for calibration) are arranged alternately along the axial direction. The first embossing portion is used to form a first embossing segment in the active region of the positive electrode precursor, and the second embossing portion is used to form a second embossing segment in the inactive region of the positive electrode precursor.

[0055] (3) In the rolling process, the above-mentioned combined embossing roller is used to roll the positive electrode sheet once, and at the same time, the corresponding embossing pattern is formed in the active coating area and the inactive area.

[0056] (4) After slitting and winding, the embossed positive electrode sheet containing the coded pattern is obtained.

[0057] (5) Encode the above-mentioned embossed positive electrode sheet with the coded pattern to generate a bound positive electrode sheet traceability code, and upload the positive electrode sheet traceability code to the MES system; wherein, bound means that the positive electrode sheet traceability code has been bound to the information of the positive electrode sheet; A CCD vision system is set up before subsequent battery assembly to identify the coded embossed pattern under specific angle lighting and convert the identification result into binary code; Decode the above binary code to obtain the positive electrode traceability code, and trace the positive electrode associated with the positive electrode traceability code to locate the position of the positive electrode.

[0058] Example 2 The difference between this embodiment and Embodiment 1 is that the specific encoding parameters are: the depth level is increased to three (d1=8μm represents "0", d2=13μm represents "1", d3=18μm represents "2", using ternary encoding), and the spacing combination is increased to five (s1=150μm represents "00", s2=250μm represents "01", s3=400μm represents "10", s4=550μm represents "11", s5=700μm represents "100"), so that the total information capacity is 128 bits, and everything else is the same as in Embodiment 1.

[0059] Example 3 The difference between this embodiment and Embodiment 1 is that the specific encoding parameters are as follows: the area of ​​the blank inactive region at the root of the tab is increased to 8mm×8mm, the depth level is increased to four (d1=8μm represents "00", d2=12μm represents "01", d3=16μm represents "10", d4=20μm represents "11"), and the spacing combination is increased to six (s1=150μm represents "000", s2=250μm represents "001", s3=400μm represents "010", s4=550μm represents "011", s5=700μm represents "100", s6=850μm represents "101"), so that the total information capacity is 256 bits. Everything else is the same as in Embodiment 1.

[0060] Example 4 The difference between this embodiment and Embodiment 1 is that in the second embossing section, the specific encoding parameters are: two depth levels (d1=2μm represents "0", d2=10μm represents "1"), while all other parameters are the same as in Embodiment 1.

[0061] Example 5 The difference between this embodiment and Embodiment 1 is that in the second embossing section, the specific encoding parameters are: two depth levels (d1=10μm represents "0", d2=25μm represents "1"), while all other parameters are the same as in Embodiment 1.

[0062] Example 6 The difference between this embodiment and Embodiment 1 is that the specific coding parameters in the second embossing section are: three spacings (s1=50μm represents "00", s2=80μm represents "01", s3=100μm represents "10"), while the others are the same as in Embodiment 1.

[0063] Example 7 The difference between this embodiment and Embodiment 1 is that in the second embossed section, the specific coding parameters are: three spacings (s1=20μm represents "00", s2=40μm represents "01", s3=60μm represents "10"), and all others are the same as in Embodiment 1.

[0064] Example 8 The difference between this embodiment and Embodiment 1 is that, in the first embossing section, the depth of the parallel striped groove is 25μm, and in the second embossing section, the maximum depth of the second embossing unit is adjusted to 3μm (d1=1μm, d2=3μm), so that the ratio of the depth of the first embossing unit (25μm) to the maximum depth of the second embossing unit (3μm) is 25:3≈8.33. All other aspects are the same as in Embodiment 1.

[0065] Example 9 The difference between this embodiment and embodiment 1 is that the depth of the parallel striped groove in the first embossing section is 5μm, and the parameters of the second embossing section are the same as those in embodiment 1 (maximum depth is 18μm), so that the ratio of the depth of the first embossing unit (5μm) to the maximum depth of the second embossing unit (18μm) is 5:18≈0.28. All other parameters are the same as those in embodiment 1.

[0066] Comparative Example 1 The difference between this comparative example and Example 1 is that the blank inactive area at the root of the positive electrode tab is not provided with a second embossing section, but a QR code is sprayed in this area for traceability using an inkjet printer. Everything else is the same as Example 1.

[0067] Comparative Example 2 The difference between this comparative example and Example 1 is that the surface of the blank inactive area at the root of the electrode is not provided with a second embossed section, but only with a QR code, which is formed by laser etching. Everything else is the same as in Example 1.

[0068] Test conditions The positive electrode sheets and their lithium-ion batteries prepared in the above embodiments and comparative examples were subjected to performance tests, and the test methods are as follows: (1) Success rate of information reading: During the conveying process after the electrode sheet is cut and before winding, the production line speed is 30m / min. A low-angle parallel light source and a CCD vision system (resolution not less than 5μm / pixel) are used to collect and decode the coded embossed area of ​​1000 consecutive electrode sheets. The number of electrode sheets that can be successfully read with all preset codes and without errors is counted, and the reading success rate is calculated.

[0069] (2) Battery cycle performance: The prepared positive electrode is assembled into a button half cell (the negative electrode is a lithium sheet), charged to 4.2V at 1C constant current and constant voltage at 25℃, and discharged to 2.8V at 1C constant current after resting for 5 minutes. The cycle is repeated 500 times, and the ratio of the discharge capacity of the 500th discharge to the first discharge capacity is recorded, which is the capacity retention rate.

[0070] The test results are shown in Table 1.

[0071] Table 1 As can be seen from Table 1, in the present invention, by setting a second embossing section with manufacturing information in the inactive area of ​​the electrode sheet, embodiments 1 to 3 of the present invention all achieved a high success rate of traceability information reading and permanent physical life, without adding any extra processes, and at the same time obtained better cycle performance.

[0072] Among them, compared with Example 1, Examples 4 to 9 have slightly lower success rates or capacity retention rates for traceability information reading because the depth of the second embossing unit, the center distance between two adjacent second embossing units, or the depth ratio between the two types of embossing units exceeds the preferred range. However, they are still better than the inkjet printing scheme of Comparative Example 1.

[0073] Comparative Example 1 uses external inkjet printing, which carries the risk of detachment and has the lowest success rate for reading traceability information. Comparative Example 2 uses laser-etched QR codes, which improves the success rate of reading traceability information to some extent, but adds an extra process and causes micro-damage to the electrode sheets, further affecting the battery's cycle performance. Therefore, the technical solution of this invention has significant advantages.

[0074] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An embossed electrode sheet containing a coded pattern, comprising a current collector and an electrode active material layer disposed on at least one side of the current collector, characterized in that, The current collector is provided with a number of active and inactive regions, and the active and inactive regions are alternately distributed along the length of the electrode. The electrode active material layer is located in the active region, and a first embossing section is provided on the surface of the electrode active material layer, the first embossing section including a plurality of first embossing units; The surface of the inactive area is provided with a second embossed section, the second embossed section includes a plurality of second embossed units, and the second embossed units have at least two different depths, and the center distance between two adjacent second embossed units in the second embossed section has at least three different spacings.

2. The embossed electrode sheet containing a coded pattern according to claim 1, characterized in that, The projected area of ​​the second embossing unit in the plane where the current collector is located corresponds to an equivalent circle diameter of 20μm~200μm; And / or, the depth of the second embossing unit is 5μm~20μm; And / or, the center distance between two adjacent second embossing units is 100μm~1000μm.

3. The embossed electrode sheet containing a coded pattern according to claim 1 or 2, characterized in that, At least two calibration embossing marks are provided at the boundary of the second embossing unit; The size of the embossed markings used for calibration is 300μm~500μm; The depth of the calibration embossing mark is the median value of the depth of different second embossing units; The embossed markings used for calibration are at least one of the following shapes: cross, circle, or polygon.

4. The embossed electrode sheet containing a coded pattern according to claim 1, characterized in that, The depth of the first embossing unit is 5% to 40% of the thickness of the electrode active material layer; And / or, the ratio of the depth of the first embossing unit to the maximum depth of the second embossing unit is 1:(0.3~3).

5. A method for preparing an embossed electrode sheet containing a coded pattern according to any one of claims 1 to 4, characterized in that, The preparation method includes the following steps: An electrode sheet precursor containing an electrode active material layer was prepared. The electrode precursor is embossed once using a combined embossing roller to obtain the embossed electrode with the coded pattern. The combined embossing roller is provided with alternating first embossing portions and second embossing portions along the axial direction. The first embossing portion is used to form a first embossing segment in the active region of the electrode sheet precursor, and the second embossing portion is used to form a second embossing segment in the inactive region of the electrode sheet precursor.

6. A method for quality traceability of electrode sheets, characterized in that, The quality traceability method includes the following steps: The embossed electrode sheet containing the coded pattern according to any one of claims 1 to 4 is encoded to generate a bound electrode sheet traceability code, and the electrode sheet traceability code is uploaded to the target system; wherein, "bound" means that the electrode sheet traceability code is bound to the information of the electrode sheet; During the preparation of the electrode sheet, image recognition technology is used to identify the coded pattern and the identification result is converted into binary code; The binary code is decoded to obtain the electrode traceability code, and the electrode associated with the electrode traceability code is traced to locate the position of the electrode.

7. The quality traceability method according to claim 6, characterized in that, During the information encoding process, nine binary digits are used to encode the depth of the second embossing unit and the center distance between two adjacent second embossing units respectively; And / or, the information of the electrode sheet includes at least one of the following: electrode sheet production batch number, coating machine number, rolling parameter group number, slitting date, or roll number.

8. The quality traceability method according to claim 6, characterized in that, The image recognition technology includes a CCD vision system.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the electrode sheet quality traceability method according to any one of claims 6 to 8.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for quality traceability of electrode sheets according to any one of claims 6 to 8.

Images