Electrode assembly repair method and apparatus

Abstract

The application discloses an electrode assembly repairing method and device, and relates to the field of battery manufacturing.The method comprises the following steps: determining a target thickness difference based on a maximum thickness value and a minimum thickness value of an electrode assembly to be repaired; arranging a target rigid gasket corresponding to the target thickness difference on the surface of the part with the minimum thickness value of the electrode assembly to be repaired, so as to obtain a target electrode assembly to be repaired; and controlling a hot-pressing device to perform pressure processing on the target electrode assembly to be repaired by using a preset stepped pressure maintaining control strategy, so as to realize thickness repairing of the electrode assembly.The stepped pressure maintaining control strategy comprises at least one pressure increasing-pressure maintaining stage and one stress releasing stage.The electrode assembly with uneven thickness is not directly discarded, but is effectively repaired by using the target rigid gasket and the stepped pressure maintaining control mode, so that material waste and cost loss can be avoided, and the internal structure and electrochemical performance of the electrode assembly can be prevented from being damaged.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, specifically to a method and apparatus for repairing electrode components. Background Technology

[0002] Rechargeable batteries, as a highly efficient energy storage device, are widely used in consumer electronics, electric vehicles, and energy storage systems. During battery manufacturing, the thickness and uniformity of the electrode assembly (typically formed by winding or stacking positive electrode sheets, negative electrode sheets, and separators) are among the key process parameters determining the final quality, performance, and safety of the battery. Ideally, the electrode assembly should have a highly consistent thickness to ensure uniform internal stress distribution and good interface contact during subsequent encapsulation, formation, and modular integration.

[0003] However, in the actual winding or stacking production process, due to various factors such as fluctuations in electrode coating thickness, unstable substrate tension control, and equipment mechanical precision errors, the electrode assembly after hot pressing often has uneven thickness. Typically, one side of the electrode assembly is thicker than the other side, forming a thickness difference.

[0004] In related technologies, there are two main ways to handle such non-conforming products: the first is to scrap them directly, which is simple and direct, but will cause huge material waste and cost losses; the second is to perform overall re-compression, that is, to put the entire electrode assembly with uneven thickness back into the hot press and apply greater pressure to compress it as a whole. Although this method can compress the thicker side of the electrode assembly to the target size, the electrode assembly may be subjected to excessive pressure far exceeding the process requirements. This overpressure will cause irreversible damage to the electrode assembly, such as diaphragm damage, electrode damage, and uncontrollable electrochemical performance.

[0005] Therefore, how to effectively repair uneven thickness of electrode components while avoiding damage to the internal structure and electrochemical performance of the electrode components is an urgent problem to be solved. Summary of the Invention

[0006] This application provides an electrode assembly repair method and apparatus, which can solve the technical problems in the prior art such as material waste, cost loss and irreversible electrode assembly damage caused by directly scrapping or overall repressing of electrode assemblies with uneven thickness.

[0007] In a first aspect, embodiments of this application provide a method for repairing an electrode assembly, including: The target thickness difference is determined based on the maximum and minimum thickness values ​​of the electrode assembly to be repaired; A target rigid pad corresponding to the target thickness difference is disposed on the surface of the portion of the electrode assembly to be repaired having the minimum thickness value, thereby obtaining the target electrode assembly to be repaired; The target electrode assembly to be repaired is pressurized by a hot pressing device through a preset stepped pressure holding control strategy to achieve electrode assembly thickness repair. The stepped pressure holding control strategy includes at least one pressurization-pressure holding stage and one stress relief stage.

[0008] In conjunction with the first aspect, in one embodiment, the pressure boosting-holding stage includes: The hot press equipment is controlled to linearly increase the pressure to a preset target pressure at a preset rate, and then maintain the pressure at the preset target pressure for a first preset time.

[0009] In conjunction with the first aspect, in one embodiment, the stress relief stage includes: The hot press equipment is depressurized to a preset intermediate pressure and held at the preset intermediate pressure for a second preset duration, wherein the preset intermediate pressure is less than the preset target pressure.

[0010] In conjunction with the first aspect, in one embodiment, the step of controlling the hot pressing equipment to pressurize the target electrode assembly to be repaired through a preset stepped pressure holding control strategy includes: The target electrode assembly to be repaired is placed in the hot pressing device; The hot press equipment is controlled to pressurize to a first preset pressure at a preset speed, and then remain at the first preset pressure for a third preset time, wherein the first preset pressure is less than the preset target pressure; The hot pressing equipment is controlled to sequentially execute the pressure increase-pressure holding stage and the stress relief stage.

[0011] In conjunction with the first aspect, in one embodiment, after the steps of controlling the hot pressing device to sequentially perform the pressure-holding stage and the stress relief stage, the method further includes: Control the hot press equipment to execute the pressurization-holding stage again in sequence; After the pressurization-holding stage is completed, the hot pressing equipment is completely depressurized, and the target electrode assembly to be repaired is transferred to the cooling equipment for shaping, so as to achieve the thickness repair of the electrode assembly.

[0012] In conjunction with the first aspect, in one embodiment, the electrode assembly to be repaired is formed by hot-pressing an original electrode assembly using the hot-pressing equipment. The operating temperature corresponding to the hot-pressing process is a conventional pressurization temperature, and the operating pressure corresponding to the hot-pressing process is a conventional pressurization pressure. When the hot-pressing equipment pressurizes the target electrode assembly to be repaired, its corresponding operating temperature is a preset target temperature, and the preset target temperature is lower than the conventional pressurization temperature, and the preset target pressure is lower than the conventional pressurization pressure.

[0013] In conjunction with the first aspect, in one embodiment, the method further includes: An anti-stick buffer layer is provided on the contact surface between the target rigid pad and the electrode assembly to be repaired.

[0014] In conjunction with the first aspect, in one embodiment, prior to the step of disposing a target rigid pad corresponding to the target thickness difference on the surface of the portion of the electrode assembly to be repaired having the minimum thickness value, the method further includes: Determine whether the target thickness difference is not greater than a preset thickness difference threshold and whether the minimum thickness value is not less than a preset thickness threshold; If so, then perform the step of placing a target rigid pad corresponding to the target thickness difference on the side surface of the electrode assembly to be repaired that has the minimum thickness value; If not, the electrode assembly to be repaired shall be scrapped.

[0015] In conjunction with the first aspect, in one embodiment, after the step of controlling the hot pressing equipment to pressurize the target electrode assembly to be repaired through a preset stepped pressure holding control strategy to achieve electrode assembly thickness repair, the method further includes: The thickness of the repaired electrode assembly was measured at multiple points to obtain multiple thickness values; If all the multiple thickness detection values ​​are within the preset standard thickness range, and the range between the maximum and minimum values ​​among the multiple thickness detection values ​​is less than or equal to the preset range threshold, then the repaired electrode assembly is deemed qualified. If the maximum value among the multiple thickness detection values ​​is greater than the upper limit of the standard thickness range or the range value is greater than the range threshold, the target rigid shim will be replaced with a rigid shim with a thickness increased by a preset thickness value for secondary repair. If the minimum value among the multiple thickness detection values ​​is less than the lower limit of the standard thickness range, the electrode assembly to be repaired shall be scrapped.

[0016] Secondly, embodiments of this application provide an electrode assembly repair device, comprising: Thickness determination module, which is used to determine the target thickness difference based on the maximum and minimum thickness values ​​of the electrode assembly to be repaired; A thickness compensation module is used to place a target rigid pad corresponding to the target thickness difference on the surface of the portion of the electrode assembly to be repaired having the minimum thickness value, thereby obtaining the target electrode assembly to be repaired. The thickness repair module is used to control the hot pressing equipment to pressurize the target electrode assembly to be repaired through a preset stepped pressure holding control strategy, so as to achieve thickness repair of the electrode assembly. The stepped pressure holding control strategy includes at least one pressure increase-pressure holding stage and one stress relief stage.

[0017] The beneficial effects of the technical solutions provided in this application include: The target thickness difference is determined by the maximum and minimum thickness values ​​of the electrode assembly to be repaired. A target rigid shim corresponding to the target thickness difference is placed on the surface of the portion of the electrode assembly with the minimum thickness value. This allows the repair pressure to be precisely applied to the thicker area of ​​the electrode assembly, while the thinner area is isolated and protected by the target rigid shim. This allows for modification of the electrode assembly by applying less pressure, fundamentally avoiding problems such as diaphragm pore closure and electrode damage caused by overpressure. A stepped pressure holding control strategy is used to control the hot pressing equipment to pressurize the target electrode assembly with the target rigid shim. The stepped pressure holding control strategy includes at least one pressurization-holding stage and one stress relief stage, thereby effectively releasing the complex stress generated inside the electrode assembly due to compression, significantly reducing thickness rebound after hot pressing, and making the final dimensions more stable and accurate. As can be seen, this application does not directly scrap the electrode assembly with uneven thickness, but effectively repairs the electrode assembly with uneven thickness by using a target rigid gasket and a stepped pressure control method. This not only avoids material waste and cost loss, but also avoids damage to the internal structure and electrochemical performance of the electrode assembly. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating an embodiment of the electrode assembly repair method of this application; Figure 2 This is a cross-sectional view of the electrode assembly before repair in the embodiments of this application; Figure 3 This is a cross-sectional view of the electrode assembly after the target rigid pad has been placed, as described in the embodiments of this application. Figure 4 This is a cross-sectional view of the electrode assembly under repair involved in the embodiments of this application. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0020] First, some of the technical terms used in this application will be explained to help those skilled in the art understand this application.

[0021] Separator damage: Under high pressure and high temperature, the separator will undergo plastic deformation and creep, which may even lead to the closure or complete blockage of micropores, severely affecting the lithium-ion transport channel, resulting in increased battery internal resistance and a sharp decline in rate performance.

[0022] Electrode damage: Excessive surface pressure may damage the structure of the active material particles or cause the binder to fail, resulting in the active material peeling off from the current collector.

[0023] Uncontrollable electrochemical performance: Even if the external dimensions are qualified, the internal structure may be damaged, and there are huge hidden dangers in the electrochemical performance, which poses a risk to the long-term reliability and safety of the battery.

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0025] In a first aspect, embodiments of this application provide a method for repairing an electrode assembly.

[0026] In one embodiment, reference is made to Figure 1 , Figure 1 This is a flowchart illustrating an embodiment of the electrode assembly repair method of this application. Figure 1 As shown, the electrode assembly repair method includes: Step S10: Determine the target thickness difference based on the maximum and minimum thickness values ​​of the electrode assembly to be repaired on both sides.

[0027] As an example, it should be noted that the electrode assembly to be repaired refers to a defective electrode assembly with uneven thickness after hot pressing, such as... Figure 2 The square electrode assembly with uneven thickness shown (i.e. Figure 2The blue trapezoid in the image has a design dimension of 120 mm long × 30 mm wide and a target thickness of 16.2 mm. In this embodiment, a high-precision height gauge or laser thickness gauge can be preferably used to measure the thickness of the upper and lower surfaces near the four corner points on opposite sides (such as the left and right sides or the front and back sides) of the electrode assembly to be repaired, for a total of 8 measurement points. All measurement values ​​are recorded to obtain the maximum thickness value H_max and the minimum thickness value H_min. Then, the target thickness difference ΔH is calculated based on the maximum thickness value H_max and the minimum thickness value H_min. For example, see... Figure 2 As shown, assuming the maximum thickness of the electrode assembly to be repaired is H_max = 16.8 mm and the minimum thickness is H_min = 16.2 mm, then the target thickness difference ΔH = H_max - H_min = 16.8 - 16.2 = 0.6 mm.

[0028] Step S20: A target rigid pad corresponding to the target thickness difference is disposed on the surface of the portion of the electrode assembly to be repaired having the minimum thickness value, thereby obtaining the target electrode assembly to be repaired. The portion having the minimum thickness value does not necessarily have the minimum thickness across its entire length; it may have an area slightly thicker than the minimum thickness value, in addition to covering the area with the minimum thickness value. For example, the maximum thickness of this portion having the minimum thickness value is approximately 0.2 mm greater than the minimum thickness value.

[0029] Exemplary, see Figure 3 As shown, the portion with the minimum thickness value is one side of the electrode assembly to be repaired. A target rigid pad (i.e., Figure 3 The target rigid pad (represented by the red rectangle in the diagram) is placed on the surface of the electrode assembly with a thickness of 16.2 mm on one side. It should be noted that the thickness T_shim of the target rigid pad matches the target thickness difference ΔH, such as T_shim = 0.6 mm ± 0.02 mm. Furthermore, to ensure uniform pressure transmission and prevent damage to the electrode assembly surface, the target rigid pad is preferably made of a high-rigidity material (such as 304 stainless steel) and preferably has a surface roughness Ra ≤ 0.4 µm. Simultaneously, the dimensions of the target rigid pad are preferably designed to be slightly longer than the surface of the electrode assembly to be repaired, forming a skirt extending beyond the end of the electrode assembly to prevent indentations at the edges. For example, if the design dimensions of the electrode assembly to be repaired are 120 mm long × 30 mm wide, the dimensions of the target rigid pad can be set to 124 mm long × 10 mm wide, making the length of the target rigid pad 4 mm longer than the length of the electrode assembly to be repaired, thus preventing edge indentations on the electrode assembly.

[0030] Further, in one embodiment, before the step of disposing a target rigid pad corresponding to the target thickness difference on the surface of the portion of the electrode assembly to be repaired having the minimum thickness value, the method further includes: Determine whether the target thickness difference is not greater than a preset thickness difference threshold and whether the minimum thickness value is not less than a preset thickness threshold; If so, then perform the step of placing a target rigid pad corresponding to the target thickness difference on the surface of the portion of the electrode assembly to be repaired having the minimum thickness value; If not, the electrode assembly to be repaired shall be scrapped.

[0031] As an example, in this embodiment, a repair criterion will be preset to determine whether the electrode assembly to be repaired meets the conditions for entering the repair process of this embodiment, and the repair criterion can be set based on the critical compression rate of the internal diaphragm of the electrode assembly. For example, for an electrode assembly to be repaired with a target thickness of 16.2 mm, the repair standard can be set as follows: the minimum thickness value H_min is not less than 16.0 mm and the thickness difference ΔH is not greater than 0.7 mm. That is, the preset thickness threshold is 16.0 mm and the preset thickness difference threshold is 0.7 mm. Setting the preset thickness threshold to 16.0 mm ensures that the membrane porosity is not lower than the physical red line of the safety threshold (such as 35%). That is, if the minimum thickness value H_min is less than 16.0 mm, it means that the electrode assembly has irreversible electrochemical damage, and it is meaningless to repair it at this time. At the same time, setting the preset thickness difference threshold (i.e., the upper limit of the difference) to 0.7 mm ensures that the deformation during the repair process is within the effective plasticity zone of the material. That is, if the thickness difference ΔH is too large, it will not only cause the local pressure to exceed the membrane pore pressure, but also the forced flattening will induce cracks or peeling of the electrode coating.

[0032] Based on this, after determining the target thickness difference ΔH of the electrode assembly to be repaired, it is necessary to further determine whether the target thickness difference ΔH is not greater than the preset thickness difference threshold and whether the minimum thickness value H_min is not less than the preset thickness threshold. If so, it means that the electrode assembly to be repaired meets the above repair criteria. In this embodiment, the subsequent repair process will be performed on it to control the increase of the Gurley value (i.e., the air permeability value, used to characterize the air permeability of the separator) after repair to within 10%, thereby ensuring the consistency of the battery rate performance with the original design scheme. If the target thickness difference ΔH is greater than the preset thickness difference threshold or the minimum thickness value H_min is less than the preset thickness threshold, it means that the thickness difference of the electrode assembly to be repaired is too large or there is irreversible electrochemical damage. In this case, there is no need to repair it, and it can be directly scrapped.

[0033] Furthermore, in one embodiment, the method further includes: An anti-stick buffer layer is provided on the contact surface between the target rigid pad and the electrode assembly to be repaired.

[0034] As an example, in this embodiment, a non-stick buffer layer may preferably be provided on the contact surface between the target rigid gasket and the electrode assembly to be repaired, in order to fill the tiny gap between the target rigid gasket and the electrode assembly to be repaired and eliminate stress concentration points. The anti-stick buffer layer is preferably a Teflon (PTFE) anti-stick layer. The PTFE layer, with its relatively low hardness, can achieve microscopic elastic deformation under a preset target pressure. Furthermore, it should be understood that the thickness of the anti-stick buffer layer can be determined according to actual needs and is not limited here. However, if the anti-stick buffer layer is too thin (e.g., <0.01 mm), it is prone to wear and peeling after repeated hot pressing, losing its anti-stick function and failing to buffer stress. If it is too thick (e.g., >0.2 mm), it will generate significant thermal resistance, and due to the enhanced creep characteristics of the polymer, it will introduce uncontrollable displacement deviations. Therefore, the thickness of the anti-stick buffer layer can be set to 0.01 mm-0.2 mm, preferably 0.05 mm, but can also be 0.02 mm, 0.1 mm, 0.15 mm, etc., to maintain the anti-stick function and buffer stress while avoiding thermal resistance and uncontrollable displacement deviations. Step S30: The hot pressing equipment is controlled to pressurize the target electrode assembly to be repaired by a preset stepped pressure holding control strategy to achieve electrode assembly thickness repair. The stepped pressure holding control strategy includes at least one pressure increase-pressure holding stage and one stress relief stage.

[0035] Exemplary and noteworthy, the hot pressing equipment refers to equipment capable of pressurizing electrode components, such as a hot press. In this embodiment, the stepped pressure holding control strategy refers to a multi-stage, dynamically changing pressure loading strategy employed by the hot pressing equipment. This strategy does not follow the traditional single-stage approach of "increasing pressure to the target value once and maintaining it until the end," but rather includes at least one pressure increase-holding stage and one stress relief stage. The pressure increase-holding stage involves increasing the pressure on the hot pressing equipment (e.g., linearly increasing it) after the electrode component has stabilized, and then holding the pressure after reaching a certain level to allow for the completion of the main deformation. The stress relief stage involves rapidly depressurizing the hot pressing equipment after the pressure holding period and holding it after reaching a certain low pressure. This allows the highly compressed polymer material (diaphragm, binder) segments inside the electrode component to relax and rearrange, releasing internal stress.

[0036] Based on this, in the process of pressurizing the target electrode assembly to be repaired, the hot pressing equipment of this embodiment can control the pressure of the hot pressing equipment to sequentially execute one or more pressurization-holding stages and stress relief stages. This effectively releases the complex stress generated inside the electrode assembly due to compression, significantly reduces the thickness rebound after hot pressing, and makes the final dimensions more stable and accurate, thereby achieving effective repair of the electrode assembly thickness. It is worth noting that the pressurization-holding stage can preferably be executed in a linear manner to ensure a constant load growth rate, avoid pressure sudden changes that may occur at the end of nonlinear loading, thereby protecting the electrode assembly from instantaneous overpressure damage. It also facilitates high-precision closed-loop feedback of the servo system, effectively preventing pressure overshoot caused by mechanical inertia, thereby ensuring absolute precision in pressure control.

[0037] It should be understood that when pressurizing the target electrode assembly to be repaired with the target rigid gasket, although the hot press plate in the hot press equipment will simultaneously contact the thick and thin areas of the target electrode assembly (i.e., the areas where the target rigid gasket is applied), the compressive deformation of the target rigid gasket is almost negligible because it is a highly rigid material. During the hot pressing process, for the thin area, the downward displacement of the hot press plate is "held back" by the target rigid gasket. This makes the thin area electrode assembly actually under a kind of displacement shielding protection, that is, it bears static pressure rather than forced thinning deformation. In other words, the target rigid gasket physically cuts off the "force feedback" path of the thin area to the downward displacement of the hot press plate (the thin area is almost...). (In contrast, the thick area is not protected by the target rigid pad, and all the downward displacement of the hot press plate is directly applied to the thick area. The effective output power of the hot press is almost entirely concentrated on the thick area. Without the target rigid pad, the thin area is also "part of the load". When the hot press plate presses down the thick area, it must also press down the thin area (the thick and thin areas are simultaneously subjected to compressive resistance to the hot press plate). Therefore, compared with not setting the target rigid pad, by setting the target rigid pad, the hot press equipment can apply less pressure to compress the thick area to the same target thickness, which can avoid damage to the electrode assembly due to overpressure.

[0038] Furthermore, in the repair method of this embodiment, both the thick and thin areas are compressed. However, after the pressurization process is completed, the electrode assembly will inevitably experience some rebound, and the rebound of the thick area is usually less than that of the thin area. This reduces the thickness difference between the thick and thin areas after repair. Therefore, this embodiment can reduce the thickness difference between the thick and thin areas while protecting the electrode assembly from overpressure.

[0039] In summary, this embodiment does not directly scrap the electrode assembly with uneven thickness. Instead, it effectively repairs the electrode assembly with uneven thickness by using a target rigid gasket and a stepped pressure control method. This not only avoids material waste and cost loss, but also avoids damage to the internal structure and electrochemical performance of the electrode assembly.

[0040] Furthermore, in one embodiment, the electrode assembly to be repaired is formed by hot-pressing an original electrode assembly using the hot-pressing equipment. The operating temperature corresponding to the hot-pressing process is the conventional pressurization temperature, and the operating pressure corresponding to the hot-pressing process is the conventional pressurization pressure. When the hot-pressing equipment pressurizes the target electrode assembly to be repaired, its corresponding operating temperature is a preset target temperature, and the preset target temperature is lower than the conventional pressurization temperature, and the preset target pressure is lower than the conventional pressurization pressure.

[0041] As an example, it should be noted that the electrode assembly to be repaired is formed by hot pressing the original electrode assembly using a hot pressing device. The working temperature and pressure corresponding to this hot pressing process are the conventional pressurization temperature and pressure. The preset target temperature T_set refers to the constant working temperature maintained on the surface of the hot pressing plate of the hot pressing device during the process of repairing uneven thickness of the electrode assembly, while the preset target pressure P_set refers to the peak pressure value applied to the electrode assembly by the hot pressing device. In this embodiment, it is preferable to set the preset target temperature T_set to be lower than the conventional pressurization temperature (e.g., 100°C), for example, T_set is set in the range of 70°C to 90°C, and the preset target pressure P_set is set to be lower than the conventional pressurization pressure (e.g., 9 tons), so that the surface pressure generated by the preset target pressure is in the range of 0.2 MPa to 0.5 MPa.

[0042] Specifically, assuming the conventional pressurization temperature is 100℃, the preset target temperature T_set can be set to 80℃ to reduce the risk of membrane creep by 20℃. It should be understood that the critical softening temperature of lithium battery membranes (such as PE-based membranes) is usually between 85-90℃, while the conventional pressurization temperature of 100℃ is to pursue the ultimate interfacial bonding force. However, in the repair process, the electrode assembly structure is basically finalized. Therefore, setting the working temperature of the hot press plate to 80℃ can avoid the severe thermal shrinkage and micropore collapse zone of the membrane, ensuring that the increase in membrane permeability is controlled within a safe range of less than 10% under the repair pressure. In addition, the conventional pressurization process is a reshaping process, while the repair process in this embodiment is a fine-tuning process. Therefore, setting T_set to 80℃ is the optimal balance point that takes into account both deformation locking efficiency and protection of the membrane microstructure.

[0043] Furthermore, assuming the conventional pressurization pressure is 9 tons, the preset target pressure P_set can be preferably set to 4.5 tons, half the original pressure. For an electrode assembly area of ​​120mm × 30mm, this preset target pressure is approximately equal to a surface pressure of 0.35 MPa. It is understandable that there is a significant density gradient between the thick and thin sides of the electrode assembly to be repaired; that is, the thick side structure is relatively loose, and the critical load required for plastic deformation is much lower than that of the compacted thin side. The 4.5-ton P_set falls precisely within the load range where permanent deformation occurs on the thick side and elastic stability is maintained on the thin side. Meanwhile, the repair process involves a secondary hot-pressing process for the electrode assembly. If the conventional pressure of 9 tons is used, it is easy to generate a stress superposition effect, causing the diaphragm to undergo excessive thermoplastic flow under the dual effects of high temperature and high pressure, resulting in a significant increase in air permeability. Based on this, the core purpose of reducing the pressure by 50% in this embodiment is to ensure that the pressure is "flat" while strictly adhering to the technical red line of not closing the pores. It can also avoid the mechanical crushing of active material particles caused by secondary processing and the shear stress generated on the current collector, thereby ensuring that the electrochemical performance of the repaired electrode assembly is highly consistent with that of the genuine electrode assembly.

[0044] Furthermore, in one embodiment, the pressure boosting-holding stage includes: The hot press equipment is controlled to linearly increase the pressure to a preset target pressure at a preset rate, and then maintain the pressure at the preset target pressure for a first preset time.

[0045] As an example, it should be noted that the specific value of the preset rate can be determined based on actual repair needs, electrode component material characteristics, and the rheological properties of the binder at different temperatures, and is not limited here. For lithium battery electrode components, which are viscoelastic porous materials, the pressurization rate determines the smoothness of gas expulsion from the internal interlayer. Excessive pressurization can cause pressure shocks, leading to excessive stress concentration at high points on the surface and damage to the separator. Therefore, the preset rate can be set to 0.3 t / s to achieve quasi-static loading, ensuring that pressure is smoothly and uniformly transferred from the outer layer to the core of the electrode component. Furthermore, this preset rate effectively matches the rheological properties of the binder at 80°C. The specific value of the first preset duration can be determined according to actual needs, as long as the corresponding pressurization process provides the necessary material adaptation window to maximize the proportion of effective plastic deformation and reduce subsequent rebound without damaging the physical structure of the separator. For example, the first preset duration is preferably set to 15 seconds.

[0046] Based on this, in the first pressurization-holding stage, this embodiment can linearly pressurize to a preset target pressure (e.g., 4.5 tons) at a rate of 0.3 t / s, and hold the pressure at this preset target pressure for 15 seconds to complete the main deformation of the target electrode assembly to be repaired.

[0047] Furthermore, in one embodiment, the stress relief stage includes: The hot press equipment is depressurized to a preset intermediate pressure and held at the preset intermediate pressure for a second preset duration, wherein the preset intermediate pressure is less than the preset target pressure.

[0048] As an example, it should be noted that the preset intermediate pressure P_mid refers to the target pressure value that needs to be maintained during the stress relief stage. Its specific value can be determined according to actual needs, as long as it is significantly lower than the preset target pressure. For example, if the preset target pressure is 4.5 tons, the preset intermediate pressure P_mid can be set to 0.5 tons. The specific value of the second preset duration can be determined according to actual needs, as long as it allows the highly compressed polymer material (such as diaphragm, binder, etc.) segments inside the electrode assembly to have time to relax and rearrange. For example, the second preset duration is preferably set to 2 seconds.

[0049] Based on this, after the pressure holding is completed, this embodiment can control the hot pressing equipment to quickly depressurize to the preset intermediate pressure P_mid of 0.5 tons, and stay at this low pressure for 2 seconds, so that the highly compressed polymer material chain segments inside the electrode assembly have time to relax and rearrange, so as to release internal stress.

[0050] Furthermore, in one embodiment, the step of controlling the hot pressing equipment to pressurize the target electrode assembly to be repaired through a preset stepped pressure holding control strategy includes: The target electrode assembly to be repaired is placed in the hot pressing device; The hot press equipment is controlled to pressurize to a first preset pressure at a preset speed, and then remain at the first preset pressure for a third preset time, wherein the first preset pressure is less than the preset target pressure; The hot pressing equipment is controlled to sequentially execute the pressure increase-pressure holding stage and the stress relief stage.

[0051] In this exemplary embodiment, the target electrode assembly to be repaired, with a target rigid gasket, can be transferred to a servo hot press. The flatness of the upper and lower pressure plates of the hot press is preferably ≤0.02 mm and the temperature control accuracy is preferably ±2 ℃. Then, the target electrode assembly to be repaired is pressurized under a preset target temperature T_set and a preset target pressure P_set that are lower than the conventional pressurization temperature and pressure.

[0052] Specifically, the first step is pre-pressing and mold closing, see [link / reference] Figure 4As shown, the upper pressure plate of the hot pressing equipment is pressurized to a first preset pressure at a preset speed, and then held at the first preset pressure for a third preset time to ensure that the target electrode assembly to be repaired is in full contact with the hot pressing plate and stabilized. The specific values ​​of the first preset pressure and the third preset time can be determined according to actual needs, as long as the first preset pressure is significantly lower than the preset target pressure. For example, setting the first preset pressure to 0.5 tons and the third preset time to 2 seconds allows the interlayer air (i.e., the minute air gaps inside the electrode assembly) to escape smoothly by holding at a low load of 0.5 tons for 2 seconds, thus avoiding local wrinkles caused by air blockage during the high-pressure stage. Simultaneously, the slight pressure of 0.5 tons can establish a stable heat conduction interface, and the 2-second heat wetting allows the target rigid gasket to fully contact the surface of the target electrode assembly to be repaired and allows for fine-tuning of the temperature of the target electrode assembly to be repaired, providing a uniform temperature field basis for subsequent stepped pressure holding. Furthermore, the magnitude of the preset speed is directly related to the instantaneous overshoot pressure. That is, if the speed is too fast, the kinetic energy pulse generated at the moment of mold closing will exceed the preset point of 0.5 tons, causing the electrode assembly to be damaged due to concentrated force on the edge. Therefore, in this embodiment, the preset speed is preferably set to 2 mm / s based on the high stability speed set by the servo feedback accuracy, so as to minimize the kinetic energy impact, ensure that the mold closing process is a quasi-static loading, and ensure the accuracy of the repair starting point.

[0053] Based on this, the hot platen in this embodiment preferably descends at a speed of 2 mm / s. When the pressure sensor reading reaches 0.5 tons, it pauses for 2 seconds to allow the electrode assembly to fully contact and stabilize with the platen. Then, the pressure-holding stage and stress relief stage are executed one or more times in sequence.

[0054] Furthermore, in one embodiment, after the steps of controlling the hot pressing device to sequentially perform the pressure-holding stage and the stress relief stage, the method further includes: Control the hot press equipment to execute the pressurization-holding stage again in sequence; After the pressurization-holding stage is completed, the hot pressing equipment is completely depressurized, and the target electrode assembly to be repaired is transferred to the cooling equipment for shaping, so as to achieve the thickness repair of the electrode assembly.

[0055] In this exemplary embodiment, after completing the initial pressurization-holding stage and stress relief stage, the hot pressing equipment is controlled to perform a second pressurization-holding stage, that is, pressurizing to 4.5 tons again at a rate of 0.3 t / s and holding for 15 seconds to eliminate the slight rebound generated after stress relief and to finally solidify the dimensions; finally, depressurization and cooling are performed, that is, after holding for 15 seconds, the hot pressing equipment is controlled to completely depressurize, and the target electrode assembly to be repaired is transferred to a cooling device (such as a cold pressing plate) at 25°C and left for 5 seconds. After rapid cooling and shaping, it is taken out to obtain the repaired electrode assembly.

[0056] Furthermore, in one embodiment, after controlling the hot pressing equipment to pressurize the target electrode assembly to be repaired through a preset stepped pressure holding control strategy to achieve electrode assembly thickness repair, the method further includes: The thickness of the repaired electrode assembly was measured at multiple points to obtain multiple thickness values; If all the multiple thickness detection values ​​are within the preset standard thickness range, and the range between the maximum and minimum values ​​among the multiple thickness detection values ​​is less than or equal to the preset range threshold, then the repaired electrode assembly is deemed qualified. If the maximum value among the multiple thickness detection values ​​is greater than the upper limit of the standard thickness range or the range value is greater than the range threshold, the target rigid shim will be replaced with a rigid shim with a thickness increased by a preset thickness value for secondary repair. If the minimum value among the multiple thickness detection values ​​is less than the lower limit of the standard thickness range, the electrode assembly to be repaired shall be scrapped.

[0057] As an example, in this embodiment, the thickness of the repaired electrode assembly can be measured at multiple points (e.g., the four corner points on the left and right sides or the front and back sides of the repaired electrode assembly, totaling eight points) immediately, to obtain multiple thickness detection values. The quality of the repaired electrode assembly is determined based on whether the multiple thickness detection values ​​fall within a preset standard thickness range and whether the range between the maximum and minimum values ​​among the multiple thickness detection values ​​is less than or equal to a preset range threshold. It should be noted that the specific values ​​of the standard thickness range and the range threshold can be determined according to the quality requirements of the battery electrode sheet and are not limited here. For example, the standard thickness range is preferably set to 16.1 mm to 16.4 mm, and the range threshold is preferably set to 0.2 mm.

[0058] Based on this, if all measured values ​​are between 16.1 mm and 16.4 mm, and the range (H_max-H_min) ≤ 0.2 mm, it is judged as PASS, that is, the repaired electrode assembly is qualified and flows into the next process; however, if there is a thickness value < 16.1 mm, it is directly judged as SCRAP (overpressure scrap), that is, the electrode assembly to be repaired is scrapped.

[0059] However, if the thickness value still exceeds 16.4 mm or the range is greater than 0.2 mm, it is considered a REWORK (rework). In this case, a rigid shim with a thickness increased by a preset value can be used as the target rigid shim for a second repair. The preset thickness value can be determined according to actual needs; for example, if it is set to 0.2 mm, the original 0.6 mm thick target rigid shim can be replaced with a 0.8 mm thick target rigid shim for the second repair. It should be understood that the hot press operates in constant pressure mode, not fixed stroke mode. Therefore, if the 0.6 mm target rigid shim fails to compress the thick area to below 16.4 mm, it indicates that the plastic deformation of the thick area has reached its bottleneck under a 4.5-ton load. In this case, the thickness of the target rigid shim is increased to 0.8 mm. The purpose of using 0.8 mm is not to forcibly increase the thickness of the thin area, but to improve the effective utilization of the load. A thicker shim effectively raises the rigidity reference surface of the thin side. Under constant pressure, the pressure vector can be more concentrated and directed towards the thick area, thereby stimulating deeper plastic deformation in the thick area beyond the initial repair. It can be understood that the final repair thickness is the result of a trade-off between "plastic deformation" and "elastic rebound." The 0.8 mm target rigid shim provides a larger compensation margin, giving the thin side a certain "elastic recovery margin" after repair, while the thick side, being more thoroughly compacted, has its rebound suppressed. The combination of these two factors ultimately achieves a convergence of the overall thickness towards the 16.1-16.4 mm range. Furthermore, it is worth noting that if a thickness value >16.4 mm or a range greater than 0.2 mm is still detected, the item can be directly scrapped without performing the aforementioned REWORK step. It should be noted that the above repair process is only allowed to be repeated once to prevent excessive closure of the membrane micropores or degradation of the adhesive performance due to repeated hot pressing, and to avoid hidden damage caused by over-repair, so as to ensure that the safety of the repaired battery in long-term cycling is consistent with that of the genuine battery.

[0060] Based on this, the health of the diaphragm can be randomly inspected. That is, one repaired electrode assembly is randomly selected from each batch, disassembled, and subjected to the following tests to monitor the potential impact of the process on performance: (1) Air permeability test: Measure the Gurley value of the diaphragm and require it to be ≤ 220 s, that is, compared with the baseline value of 200 s, the increase should be controlled within 10% to ensure that the diaphragm micropores are not severely closed.

[0061] (2) Peel strength test: Measure the peel strength between the positive electrode coating and the separator, and require it to be ≥ 15 N / m to ensure that the interfacial bonding force is not affected.

[0062] If any of the above indicators exceed the limit, the process parameters can be fine-tuned (such as lowering the temperature by 5°C or the pressure by 0.5t).

[0063] Furthermore, in this embodiment, all electrode assembly thickness data before / after repair, pressure-displacement curves used, equipment numbers, gasket numbers, and other information can be bound and uploaded through the MES (Manufacturing Execution System) to achieve full-process traceability.

[0064] As can be seen, this embodiment can not only selectively compress the thicker areas of the electrode assembly while protecting the thinner areas from overpressure, but also maintain the microstructure and functional integrity of the diaphragm to the maximum extent while ensuring the repair effect. At the same time, through optimized process procedures, stress rebound after compression is reduced, ensuring the stability and consistency of the dimensions after repair. Furthermore, a closed-loop quality control process is established to ensure the controllability and traceability of the repair process.

[0065] It should be noted that the specific values ​​(such as pressure, temperature, time, size, etc.) in the above embodiments are only for the presentation of the embodiments. These parameters can also be adaptively adjusted according to electrode components of different specifications and material systems, as well as actual thickness deviations. These adjustments should not deviate from the protection scope of this application. For example, the number of cycles of stepped pressure holding can be one or more. The material of the target rigid gasket can also be other materials with sufficient hardness and surface finish.

[0066] In summary, this embodiment provides a method for precise and non-destructive repair of electrode assemblies with uneven thickness, which can achieve at least the following beneficial effects: (1) Precise repair to avoid damage: By using a target rigid gasket, the repair pressure is precisely applied to the thicker area of ​​the electrode assembly, while the thinner area is "suspended" for protection, which fundamentally avoids problems such as diaphragm pore blockage and electrode damage caused by overpressure.

[0067] (2) High protection performance and high reliability: The use of "mild" hot pressing conditions (lower temperature and pressure) compared to conventional processes significantly reduces the thermal and mechanical impact on heat-sensitive materials such as diaphragms, ensuring the electrochemical performance and safety of the electrode assembly after repair.

[0068] (3) Stable dimensions and low rebound: The unique “step-type pressure holding” program effectively releases the complex stress generated by compression inside the electrode assembly through the cycle of “pressure-slow release-repressure”, significantly reducing the thickness rebound after hot pressing, making the final dimensions more stable and accurate.

[0069] (4) Closed-loop process and improved yield: It integrates incoming material judgment, process control, post-press inspection and data traceability to form a complete closed-loop process, which can not only effectively repair defective products, but also provide data support for the improvement of front-end processes, thereby systematically improving the overall yield of the production line.

[0070] (5) High operability and cost-effectiveness: The process parameters of this embodiment are clear and the process is easy to integrate into the existing production line. It can convert the scrapped electrode components into qualified products, which has extremely high economic benefits.

[0071] Secondly, embodiments of this application also provide an electrode assembly repair device.

[0072] In one embodiment, the electrode assembly repair device includes: The thickness determination module is used to determine the target thickness difference based on the maximum and minimum thickness values ​​of the electrode assembly to be repaired on both sides. A thickness compensation module is used to place a target rigid pad corresponding to the target thickness difference on the surface of the portion of the electrode assembly to be repaired having the minimum thickness value, thereby obtaining the target electrode assembly to be repaired. The thickness repair module is used to control the hot pressing equipment to pressurize the target electrode assembly to be repaired through a preset stepped pressure holding control strategy, so as to achieve thickness repair of the electrode assembly. The stepped pressure holding control strategy includes at least one pressure increase-pressure holding stage and one stress relief stage.

[0073] Furthermore, in one embodiment, the pressure boosting-holding stage includes: The hot press equipment is controlled to linearly increase the pressure to a preset target pressure at a preset rate, and then maintain the pressure at the preset target pressure for a first preset time.

[0074] Furthermore, in one embodiment, the stress relief stage includes: The hot press equipment is depressurized to a preset intermediate pressure and held at the preset intermediate pressure for a second preset duration, wherein the preset intermediate pressure is less than the preset target pressure.

[0075] Furthermore, in one embodiment, the thickness repair module is specifically used for: The target electrode assembly to be repaired is placed in the hot pressing device; The hot press equipment is controlled to pressurize to a first preset pressure at a preset speed, and then remain at the first preset pressure for a third preset time, wherein the first preset pressure is less than the preset target pressure; The hot pressing equipment is controlled to sequentially execute the pressure increase-pressure holding stage and the stress relief stage.

[0076] Furthermore, in one embodiment, the thickness repair module is specifically used for: Control the hot press equipment to execute the pressurization-holding stage again in sequence; After the pressurization-holding stage is completed, the hot pressing equipment is completely depressurized, and the target electrode assembly to be repaired is transferred to the cooling equipment for shaping, so as to achieve the thickness repair of the electrode assembly.

[0077] Furthermore, in one embodiment, the electrode assembly to be repaired is formed by hot-pressing an original electrode assembly using the hot-pressing equipment. The operating temperature corresponding to the hot-pressing process is the conventional pressurization temperature, and the operating pressure corresponding to the hot-pressing process is the conventional pressurization pressure. When the hot-pressing equipment pressurizes the target electrode assembly to be repaired, its corresponding operating temperature is a preset target temperature, and the preset target temperature is lower than the conventional pressurization temperature, and the preset target pressure is lower than the conventional pressurization pressure.

[0078] Furthermore, in one embodiment, an anti-stick buffer layer is provided on the contact surface between the target rigid pad and the electrode assembly to be repaired.

[0079] Furthermore, in one embodiment, the thickness compensation module is also used for: Determine whether the target thickness difference is not greater than a preset thickness difference threshold and whether the minimum thickness value is not less than a preset thickness threshold; If so, then perform the step of placing a target rigid pad corresponding to the target thickness difference on the surface of the portion of the electrode assembly to be repaired having the minimum thickness value; If not, the electrode assembly to be repaired shall be scrapped.

[0080] Furthermore, in one embodiment, the thickness repair module is also used for: The thickness of the repaired electrode assembly was measured at multiple points to obtain multiple thickness values; If all the multiple thickness detection values ​​are within the preset standard thickness range, and the range between the maximum and minimum values ​​among the multiple thickness detection values ​​is less than or equal to the preset range threshold, then the repaired electrode assembly is deemed qualified. If the maximum value among the multiple thickness detection values ​​is greater than the upper limit of the standard thickness range or the range value is greater than the range threshold, the target rigid shim will be replaced with a rigid shim with a thickness increased by a preset thickness value for secondary repair. If the minimum value among the multiple thickness detection values ​​is less than the lower limit of the standard thickness range, the electrode assembly to be repaired shall be scrapped.

[0081] The functions of each module in the electrode assembly repair device correspond to the steps in the electrode assembly repair method embodiment, and their functions and implementation processes will not be described in detail here.

[0082] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0083] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0084] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0085] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0086] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish the different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0087] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0088] The above are merely preferred embodiments of this application and do 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. A method for repairing an electrode assembly, characterized in that, include: The target thickness difference is determined based on the maximum and minimum thickness values ​​of the electrode assembly to be repaired; A target rigid pad corresponding to the target thickness difference is disposed on the surface of the portion of the electrode assembly to be repaired having the minimum thickness value, thereby obtaining the target electrode assembly to be repaired; The target electrode assembly to be repaired is pressurized by a hot pressing device through a preset stepped pressure holding control strategy to achieve electrode assembly thickness repair. The stepped pressure holding control strategy includes at least one pressurization-pressure holding stage and one stress relief stage.

2. The electrode assembly repair method as described in claim 1, characterized in that, The pressure boosting-holding stage includes: The hot press equipment is controlled to linearly increase the pressure to a preset target pressure at a preset rate, and then maintain the pressure at the preset target pressure for a first preset time.

3. The electrode assembly repair method as described in claim 2, characterized in that, The stress relief phase includes: The hot press equipment is depressurized to a preset intermediate pressure and held at the preset intermediate pressure for a second preset duration, wherein the preset intermediate pressure is less than the preset target pressure.

4. The electrode assembly repair method as described in claim 2 or 3, characterized in that, The step of controlling the hot pressing equipment to pressurize the target electrode assembly to be repaired through a preset stepped pressure holding control strategy includes: The target electrode assembly to be repaired is placed in the hot pressing device; The hot press equipment is controlled to pressurize to a first preset pressure at a preset speed, and then remain at the first preset pressure for a third preset time, wherein the first preset pressure is less than the preset target pressure; The hot pressing equipment is controlled to sequentially execute the pressure increase-pressure holding stage and the stress relief stage.

5. The electrode assembly repair method as described in claim 4, characterized in that, After the hot pressing device sequentially performs the pressurization-holding stage and the stress relief stage, the method further includes: Control the hot press equipment to execute the pressurization-holding stage again in sequence; After the pressurization-holding stage is completed, the hot pressing equipment is completely depressurized, and the target electrode assembly to be repaired is transferred to the cooling equipment for shaping, so as to achieve the thickness repair of the electrode assembly.

6. The electrode assembly repair method as described in claim 2, characterized in that: The electrode assembly to be repaired is formed by hot pressing the original electrode assembly through the hot pressing equipment. The working temperature corresponding to the hot pressing treatment is the conventional pressurization temperature, and the working pressure corresponding to the hot pressing treatment is the conventional pressurization pressure. When the hot pressing equipment pressurizes the target electrode assembly to be repaired, its corresponding working temperature is a preset target temperature, and the preset target temperature is lower than the conventional pressurization temperature, and the preset target pressure is lower than the conventional pressurization pressure.

7. The electrode assembly repair method as described in claim 1, characterized in that, The method further includes: An anti-stick buffer layer is provided on the contact surface between the target rigid pad and the electrode assembly to be repaired.

8. The electrode assembly repair method as described in claim 1, characterized in that, Prior to the step of placing a target rigid pad corresponding to the target thickness difference on the surface of the portion of the electrode assembly to be repaired having the minimum thickness value, the method further includes: Determine whether the target thickness difference is not greater than a preset thickness difference threshold and whether the minimum thickness value is not less than a preset thickness threshold; If so, then perform the step of placing a target rigid pad corresponding to the target thickness difference on the side surface of the electrode assembly to be repaired that has the minimum thickness value; If not, the electrode assembly to be repaired shall be scrapped.

9. The electrode assembly repair method as described in claim 1, characterized in that, After the step of controlling the hot pressing equipment to pressurize the target electrode assembly to be repaired through a preset stepped pressure holding control strategy to achieve electrode assembly thickness repair, the method further includes: The thickness of the repaired electrode assembly was measured at multiple points to obtain multiple thickness values; If all the multiple thickness detection values ​​are within the preset standard thickness range, and the range between the maximum and minimum values ​​among the multiple thickness detection values ​​is less than or equal to the preset range threshold, then the repaired electrode assembly is deemed qualified. If the maximum value among the multiple thickness detection values ​​is greater than the upper limit of the standard thickness range or the range value is greater than the range threshold, the target rigid shim will be replaced with a rigid shim with a thickness increased by a preset thickness value for secondary repair. If the minimum value among the multiple thickness detection values ​​is less than the lower limit of the standard thickness range, the electrode assembly to be repaired shall be scrapped.

10. An electrode assembly repair device, characterized in that, include: Thickness determination module, which is used to determine the target thickness difference based on the maximum and minimum thickness values ​​of the electrode assembly to be repaired; A thickness compensation module is used to place a target rigid pad corresponding to the target thickness difference on the surface of the portion of the electrode assembly to be repaired having the minimum thickness value, thereby obtaining the target electrode assembly to be repaired. The thickness repair module is used to control the hot pressing equipment to pressurize the target electrode assembly to be repaired through a preset stepped pressure holding control strategy, so as to achieve thickness repair of the electrode assembly. The stepped pressure holding control strategy includes at least one pressure increase-pressure holding stage and one stress relief stage.

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