A method for recycling power battery after cyclic aging

Abstract

The present invention discloses a method for recycling and utilizing a power battery after cyclic aging. The method comprises the following steps: testing the degree of cyclic aging of the power battery; adopting remanufacturing as a recycling approach to reduce recycling costs and realize the reuse of the power battery; constructing a digital twin model of the power battery, and constructing an equation for the capacitance decay trend of the power battery after cyclic aging, using the equation to draw a power battery performance decay curve corresponding to different service times, and then using the inflection point of the curve to reflect various time periods of cyclic aging of the power battery with the service time, including a stable period, a sharp period and a scrap period; using the inflection points at the beginning and end of the sharp period as the upper and lower limits of active remanufacturing of the power battery, corresponding to the service time period to match the power battery that has reached the service time period, and more accurately realizing the active remanufacturing of the power battery within the service time period.

Description

Technical Field

[0001] The present invention relates to the technical field of power battery recycling, and in particular to a method for recycling power batteries after aging. Background Art

[0002] With the increasing popularity of new energy sources, the power batteries used in new energy vehicles are showing an explosive growth trend. Under this growth trend, a large number of power batteries will be retired, that is, scrapped, in the future, and the corresponding recycling and processing levels will be under great pressure.

[0003] At present, the recycling and utilization of power batteries include three ways: remanufacturing, inscription utilization and recycling. Cascade utilization and recycling are the main ways to recycle power batteries. Among them, cascade utilization is to reassemble or process retired battery modules with good performance and meet the cascade utilization standards into new battery products for energy storage and low-speed electric vehicles. Recycling is to directly crush and disassemble retired batteries with poor performance and not meeting the cascade utilization standards to recover precious metals such as nickel, diamond and carp. Cascade utilization extends the service life of the product and is more environmentally friendly than disassembly and recycling. The remanufacturing approach is to dismantle the battery modules at the end of the life cycle, replace them with new modules, reassemble them and use them offline. Compared with cascade utilization and recycling, the process layout is reduced, and the cost is mainly reflected in the disassembly process. The remanufacturing approach is difficult to popularize due to the high process cost and high degree of environmental pollution in the past. However, new technologies such as pulse laser cleaning have emerged in the existing technology, making the power battery remanufacturing process tend to be low-cost, less polluting and highly efficient.

[0004] From the perspective of the life cycle of power batteries and the effects of recycling and treatment, in order to cope with the challenges brought by the retirement of a large number of power batteries in the future, from the perspective of cost, environmental protection and process complexity, using the current remanufacturing process as the main recycling and utilization method can undoubtedly minimize the process steps and reduce costs; however, based on the remanufacturing mechanism, power batteries cannot be remanufactured at the end of their life cycle when the capacity drops significantly or the electrodes collapse severely. Therefore, mastering the nodes of power battery remanufacturing is the key to current power battery recycling and utilization.

[0005] Therefore, in order to solve the above problems, a method for recycling and utilizing power batteries after cyclic aging is proposed. Summary of the invention

[0006] In order to make up for the deficiencies of the prior art and solve the above-mentioned problems, the present invention proposes a method for recycling and utilizing power batteries after cyclic aging.

[0007] A method for recycling power batteries after cyclic aging, the method comprising the following steps:

[0008] S1: Test the degree of cycle aging of power batteries, including mild, moderate and severe aging;

[0009] S2: Determine the recycling method of power batteries based on the degree of cycle aging;

[0010] S3: Recycle power batteries through corresponding recycling channels;

[0011] in,

[0012] In S2, the recycling pathways include remanufacturing, secondary utilization and recycling;

[0013] In S3, different recycling pathways are selected for recycling according to the degree of cycle aging of the power battery.

[0014] Preferably, in S2, the recycling and utilization path of the power battery is determined according to the node with the highest aging degree of the power battery remanufacturing, that is, the active remanufacturing node. If the aging degree of the power battery is higher than the active remanufacturing node, any one of cascade utilization and recycling is selected to recycle the power battery; if the aging degree of the power battery is lower than the active remanufacturing node, any one of remanufacturing, cascade utilization and recycling is selected to recycle the power battery.

[0015] Preferably, the method for determining the active remanufacturing node includes the following steps: establishing a digital twin model of the power battery; establishing a power battery cycle aging characteristic equation based on the power battery digital twin model; drawing a degradation condition curve of the power battery cycle aging through the equation; and corresponding the nodes where the curve changes sharply to the active remanufacturing nodes of the power battery to obtain the active remanufacturing nodes.

[0016] Preferably, in S1, the aging degrees of light, moderate and severe are all recorded with capacity decay as a feature.

[0017] Preferably, the establishment of the digital twin model of the power battery includes multi-scale conditions of electrodes, monomers, modules and the entire package, and a multi-scale imaging model of the power battery is constructed with multi-scale conditions.

[0018] Preferably, the power battery cycle aging characteristic equation established based on the power battery digital twin model specifically includes an equation characterizing the power battery cycle aging capacitance decay trend.

[0019] Preferably, the method of drawing the degradation curve of the power battery cycle aging by using an equation specifically includes taking the service time as a variable and calculating the power battery performance corresponding to different service times.

[0020] Preferably, the node where the decay condition curve changes sharply corresponds to the active remanufacturing node of the power battery, and an active remanufacturing node is obtained, wherein the decay condition curve includes a stable period, a sharp period and a scrap period, and the active remanufacturing node refers to the inflection point at the beginning and end of the sharp period, which respectively correspond to the upper and lower limits of active manufacturing.

[0021] The present invention is beneficial in that:

[0022] 1. The present invention tests the capacity of power batteries and selects remanufacturing, cascade utilization or recycling to recycle power batteries. When the capacity of the power batteries is in the battery capacity suitable for non-cascade utilization and the battery capacity for recycling, remanufacturing is used as a recycling method to reduce the recycling cost and realize the reuse of power batteries. A digital twin model of power batteries is constructed, and an equation for the decline trend of the capacitance of power batteries during cyclic aging is constructed. The performance decline curves of power batteries corresponding to different service times are plotted with the equation. The inflection points of the curve are used to reflect the various time periods of cyclic aging of the power batteries with the service time, including the stable period, the sharp period and the scrap period. The inflection points at the beginning and end of the sharp period are used as the upper and lower limits of the active remanufacturing of the power batteries. The corresponding service time period is used to match the power batteries that have reached the service time period. The active remanufacturing of the power batteries within the service time period can be more accurately realized, the cost generated by remanufacturing due to unclear performance decline of the power batteries is reduced, and the production efficiency of power battery remanufacturing is maximized. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 A flowchart of an embodiment of the present invention;

[0025] Figure 2 It is a schematic diagram of the performance degradation curve of the power battery in the present invention. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] See also Figure 1 A method for recycling power batteries after aging is shown, the method comprising the following steps:

[0028] S1: Test the degree of cycle aging of power batteries, including mild, moderate and severe aging;

[0029] S2: Determine the recycling method of power batteries based on the degree of cycle aging;

[0030] S3: Recycle power batteries through corresponding recycling channels;

[0031] in,

[0032] In S2, the recycling pathways include remanufacturing, secondary utilization and recycling;

[0033] In S3, different recycling pathways are selected for recycling according to the degree of cycle aging of the power battery.

[0034] The degree of cycle aging of power batteries is tested mainly by judging the capacity attenuation value of the power batteries, and the difference between the theoretical capacity of the power batteries and the current tested capacity is tested.

[0035] As an embodiment of the present invention, in S2, according to the node with the highest aging degree of the power battery remanufacturing, that is, the active remanufacturing node, the recycling and utilization path of the power battery is judged. If the aging degree of the power battery is higher than the active remanufacturing node, any one of the cascade utilization and recycling is selected to recycle the power battery; if the aging degree of the power battery is lower than the active remanufacturing node, any one of the remanufacturing, cascade utilization and recycling is selected to recycle the power battery; specifically, the recycling path of the power battery is judged according to the service cycle and the cycle aging degree of the power battery. First, when recycling the power battery by remanufacturing, it is necessary to avoid that the service cycle of the power battery is too long or it is at the end of its life cycle. If the service cycle of the power battery is too long or even at the end of its life cycle, its internal capacity will drop significantly and its impedance will increase sharply, which will cause obvious aging and decline phenomena such as severe collapse of the electrode, decomposition of the electrolyte, and current corrosion, making it difficult for the health state of the power battery itself to support the implementation of its remanufacturing process, and it can only be forced to choose cascade utilization or recycling, which seriously restricts the remanufacturing production space of the power battery.

[0036] As an embodiment of the present invention, the method for determining the active remanufacturing node includes the following steps: establishing a digital twin model of a power battery; establishing a power battery cycle aging characteristic equation based on the power battery digital twin model; drawing a decay operating condition curve of the power battery cycle aging through the equation; corresponding the node where the curve changes sharply to the active remanufacturing node of the power battery to obtain the active remanufacturing node; specifically, the aging and decay behavior of the power battery cell occurs under the joint action of multiple characteristic conditions, including dynamic charging and discharging, constant charging and static, and multiple physical fields (electricity, heat, force, etc.) parameter coupling, and due to the complex series-parallel structure between the power battery cells and the intertwined influence of many factors such as uneven load during operation, the performance decay trajectory between the cells shows significant inconsistency; this inconsistency is transmitted step by step with the multi-scale structure of the power battery cell level, module level, and whole package level, making it difficult to grasp the overall performance decay state of the power battery, which in turn affects the judgment of the active remanufacturing node of the power battery. Therefore, establishing a digital twin model of the power battery to reflect the decay of the power battery at each stage in digital form is an effective way to grasp the active judgment of the power battery at the manufacturing node.

[0037] As an implementation mode of the present invention, in S1, the aging degree is light, moderate and severe, and capacity decay is used as a feature for recording.

[0038] As an embodiment of the present invention, the establishment of the digital twin model of the power battery includes multi-scale conditions of electrodes, monomers, modules and the entire package, and a multi-scale image model of the power battery is constructed with multi-scale conditions.

[0039] As an implementation mode of the present invention, the power battery cycle aging characteristic equation is established based on the power battery digital twin model, specifically including an equation characterizing the power battery cycle aging capacitance decay trend.

[0040] As an implementation mode of the present invention, the degradation curve of the power battery cycle aging is drawn through an equation, specifically including taking the service time as a variable and calculating the power battery performance corresponding to different service times.

[0041] As an embodiment of the present invention, the node where the decay condition curve changes sharply corresponds to the active remanufacturing node of the power battery, and an active remanufacturing node is obtained, wherein the decay condition curve includes a stable period, a sharp period and a scrap period, and the active remanufacturing node refers to the inflection point at the beginning and end of the sharp period, which respectively correspond to the upper and lower limits of active manufacturing.

[0042] By testing the capacity of power batteries, we can choose to remanufacture, reuse or recycle power batteries. When the capacity of the power batteries is in the range of non-recycled capacity and recycled capacity, remanufacturing is used as a recycling method to reduce recycling costs and realize the reuse of power batteries. By constructing a digital twin model of power batteries and an equation for the capacitance decay trend of power battery cycle aging, the power battery performance decay curve corresponding to different service times is plotted with the equation. The inflection points of the curve are used to reflect the various time periods of cycle aging of the power batteries with service time, including the stable period, the sharp period and the scrap period. The inflection points at the beginning and end of the sharp period are used as the upper and lower limits of the active remanufacturing of the power batteries. The corresponding service time period is used to match the power batteries that have reached the service time period. This can more accurately realize the active remanufacturing of power batteries within the service time period, reduce the cost of remanufacturing due to unclear power battery performance decay, and maximize the production efficiency of power battery remanufacturing.

[0043] Research on the cycle aging degradation mechanism and active remanufacturing time-domain decision-making of power batteries based on digital twins. Research the modeling theory of digital twins for the service cycle of power batteries, explore the twin data processing method for the service cycle of power batteries; reveal the dynamic evolution and coupling mechanism of multi-physical field parameters in the process of cycle aging degradation of power batteries, and explain the cycle aging degradation mechanism of power batteries under the coupling of multiple influencing factors; explore the multi-scale performance degradation law of power batteries under the inconsistency of monomers, and form a set of active remanufacturing time-domain decision-making methods and theories for the service cycle of power batteries, so as to maximize the production benefits of power battery remanufacturing.

[0044] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0045] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for recycling power batteries after cyclic aging, characterized in that: The method comprises the following steps: S1: Test the degree of cycle aging of power batteries, including mild, moderate and severe aging; S2: Determine the recycling method of power batteries based on the degree of cycle aging; S3: Recycle power batteries through corresponding recycling channels; in, In S2, the recycling pathways include remanufacturing, secondary utilization and recycling; In S3, different recycling pathways are selected for recycling according to the degree of cycle aging of the power battery; In S2, according to the node with the highest aging degree of the power battery remanufacturing, that is, the active remanufacturing node, the recycling and utilization path of the power battery is determined. If the aging degree of the power battery is higher than the active remanufacturing node, any one of the cascade utilization and recycling is selected to recycle the power battery; if the aging degree of the power battery is lower than the active remanufacturing node, any one of the remanufacturing, cascade utilization and recycling is selected to recycle the power battery; The method for determining the active remanufacturing node comprises the following steps: constructing a power battery digital twin model; establishing a power battery cycle aging characteristic equation based on the power battery digital twin model; drawing a power battery cycle aging decay condition curve through the equation; corresponding a power battery active remanufacturing node to a node where the curve changes sharply, and obtaining an active remanufacturing node; The power battery cycle aging characteristic equation is established based on the power battery digital twin model, which specifically includes an equation that characterizes the power battery cycle aging capacitance decay trend, as follows: （1） It is the capacity loss caused by the loss of cyclable lithium ions. It is the capacity loss caused by the loss of negative electrode active materials. It is the capacitance loss caused by temperature.

2. The method for recycling power batteries after cyclic aging according to claim 1, characterized in that: In the S1, the aging degrees are mild, moderate and severe, and are all recorded with capacity decay as a feature.

3. The method for recycling power batteries after cyclic aging according to claim 2, characterized in that: The establishment of the digital twin model of the power battery includes multi-scale conditions of electrodes, monomers, modules and the entire package, and constructs a multi-scale image model of the power battery with multi-scale conditions.

4. The method for recycling power batteries after cyclic aging according to claim 3, characterized in that: The method of drawing a degradation curve of the power battery cycle aging by using an equation specifically includes taking the service time as a variable and calculating the power battery performance corresponding to different service times; Among them, the service value per unit time For measurement purposes, The analytical model is as shown in formula (2); where, is the analytical expression of the performance degradation curve, T is the new life cycle started after active remanufacturing, is the analytical expression of the performance decline curve under the new life cycle, C(t) is the other value consumed by active remanufacturing, including inspection, disassembly, and reassembly; （2）。 5. The method for recycling power batteries after cyclic aging according to claim 4, characterized in that: The node where the decay condition curve changes sharply corresponds to the active remanufacturing node of the power battery, and an active remanufacturing node is obtained, wherein the decay condition curve includes a stable period, a sharp period and a scrap period, and the active remanufacturing node refers to the inflection point at the beginning and end of the sharp period, which respectively correspond to the upper and lower limits of active manufacturing.

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