Lithium ion battery capacity limiting electrode evaluation method

Abstract

The invention discloses a lithium ion battery capacity limiting electrode evaluation method. The method comprises the following steps: S1, obtaining a positive electrode complete charging balance potential curve and a negative electrode complete discharging balance potential curve of a standard lithium ion battery; s2, assembling a lithium ion battery with a reference electrode, and performing potential measurement on the lithium ion battery with the reference electrode to obtain a local equilibrium potential curve of a positive electrode and a local equilibrium potential curve of a negative electrode; and S3, carrying out capacity limiting electrode evaluation on the lithium ion battery with the reference electrode. According to the method, the specific capacity utilized by the positive electrode and the negative electrode of the lithium ion battery with the reference electrode is rapidly obtained by utilizing a three-electrode synchronous measurement technology, so that guidance is provided for designing and developing an optimization process of the lithium ion battery.

Description

Technical Field

[0001] The invention relates to the technical field of lithium ion batteries, in particular to a method for evaluating a limited-capacity electrode of a lithium ion battery. Background Art

[0002] Lithium-ion batteries are widely used in electric vehicles, power storage, digital products, aerospace and other fields due to their advantages such as high specific energy, high power and low self-discharge. Since the lithium insertion potential of graphite is about 0.1V, which is close to the lithium metal deposition potential, the traditional lithium-ion battery system with graphite as the negative electrode usually uses the positive electrode as the capacity-limiting electrode to avoid the safety problems caused by the deposition of metallic lithium (especially lithium dendrites) on the negative electrode surface during charging.

[0003] However, with the continuous development of new negative electrode materials, negative electrode materials with higher lithium insertion potential are constantly being developed, such as niobium oxide, niobium titanium oxide, lithium yttrium titanate and other materials. These materials have higher safety and long life characteristics. Therefore, using these negative electrode materials as limited capacity electrodes will not produce lithium dendrites, and the service life of these negative electrode materials can be maximized. It can be seen that the research on limited capacity electrodes for lithium-ion batteries is very necessary.

[0004] In the traditional lithium-ion battery capacity-limiting electrode detection method, the positive and negative electrodes of the lithium-ion battery are generally assembled into standard button batteries, and the positive and negative electrode capacities are tested separately, and then the positive and negative electrode capacities are compared, and finally the electrode with the lower electrode capacity is used as the capacity-limiting electrode. The traditional detection method requires additional assembly of button batteries and separate testing of the positive and negative electrodes of the battery, which is a cumbersome process. Summary of the invention

[0005] The purpose of the present invention is to provide a lithium-ion battery limited capacity electrode evaluation method, which can solve the problem of cumbersome traditional lithium-ion battery limited capacity electrode detection methods, thereby providing guidance for the design and development optimization process of lithium-ion batteries.

[0006] To achieve the above object, the present invention provides a method for evaluating a limited-capacity electrode for a lithium-ion battery, comprising:

[0007] S1, obtaining a positive electrode complete charge equilibrium potential curve and a negative electrode complete discharge equilibrium potential curve of a standard lithium-ion battery;

[0008] S2, assembling a lithium-ion battery with a reference electrode, and measuring the potential of the lithium-ion battery with the reference electrode to obtain a local equilibrium potential curve of the positive electrode and a local equilibrium potential curve of the negative electrode;

[0009] S3, performing limited capacity electrode evaluation on the lithium ion battery having the reference electrode.

[0010] Optionally, step S1 includes:

[0011] S1.1, preparing a first standard button cell comprising a standard lithium ion battery positive electrode and a second standard button cell comprising a standard lithium ion battery negative electrode;

[0012] S1.2, charging and discharging the first standard button battery and the second standard button battery respectively to obtain a complete charging equilibrium potential curve of the positive electrode and a complete discharging equilibrium potential curve of the negative electrode of the standard lithium-ion battery.

[0013] Optionally, the standard lithium-ion battery positive electrode comprises: a positive electrode active material, a conductive agent and a binder; and the weight ratio of the positive electrode active material, the conductive agent and the binder is 8:1:1;

[0014] The standard lithium-ion battery negative electrode comprises: a negative electrode active material, a conductive agent and a binder; and the weight ratio of the negative electrode active material, the conductive agent and the binder is 8:1:1.

[0015] Optionally, the positive electrode active material is one or more of nickel cobalt manganese material, lithium cobalt oxide material, nickel cobalt aluminum material, and nickel cobalt manganese oxide material; the negative electrode active material is one or more of niobium oxide, niobium titanium oxide, and lithium yttrium titanate material.

[0016] Optionally, a first cutoff voltage and a corresponding first specific capacity value are obtained from a complete charge equilibrium potential curve of the positive electrode of the standard lithium ion battery; and a second cutoff voltage and a corresponding second specific capacity value are obtained from a complete discharge equilibrium potential curve of the negative electrode of the standard lithium ion battery.

[0017] Optionally, step S2 comprises:

[0018] S2.1, inserting a lithium-plated copper wire or lithium metal between the positive electrode and the negative electrode of another lithium-ion battery to form a lithium-ion battery with a reference electrode;

[0019] S2.2, using a three-electrode synchronous testing technique, to perform in-situ measurement on the lithium-ion battery having a reference electrode, so as to simultaneously obtain the local equilibrium potential curve of the positive electrode and the local equilibrium potential curve of the negative electrode of the battery.

[0020] Optionally, the positive electrode material of the lithium-ion battery with a reference electrode is one or more of nickel-cobalt-manganese material, lithium cobalt oxide material, nickel-cobalt-aluminum material, and nickel-cobalt-manganese oxide material; the negative electrode material of the lithium-ion battery with a reference electrode is one or more of niobium oxide, niobium-titanium oxide, and lithium yttrium titanate material.

[0021] Optionally, step S3 includes:

[0022] S3.1. Obtain the specific capacity values utilized by the positive electrode and the negative electrode of the lithium-ion battery with a reference electrode.

[0023] S3.2. Calculate the ratio M of the first specific capacity of the standard lithium-ion battery positive electrode under full charge balance to the specific capacity utilized by the positive electrode of the lithium-ion battery with a reference electrode; and calculate the ratio m of the second specific capacity of the standard lithium-ion battery negative electrode under full discharge balance to the specific capacity utilized by the negative electrode of the lithium-ion battery with a reference electrode.

[0024] S3.3. Determine whether the limiting capacity electrode of the lithium-ion battery with a reference electrode is the positive electrode or the negative electrode by comparing the magnitudes of M and m.

[0025] Optionally, if M > m, the negative electrode of the lithium-ion battery with a reference electrode is the limiting capacity electrode; if M < m, the positive electrode of the lithium-ion battery with a reference electrode is the limiting capacity electrode.

[0026] Optionally, step S3.1 includes:

[0027] Obtain the highest voltage value of the positive electrode and the lowest voltage value of the negative electrode of the lithium-ion battery with a reference electrode from the local equilibrium potential curve graph.

[0028] Read the specific capacity corresponding to the highest voltage value from the full charge balance potential curve of the standard lithium-ion battery positive electrode, and this specific capacity is the specific capacity utilized by the positive electrode of the lithium-ion battery with a reference electrode.

[0029] Read the specific capacity corresponding to the lowest voltage value from the full discharge balance potential curve of the quasi-lithium-ion battery negative electrode, and this specific capacity is the specific capacity utilized by the negative electrode of the lithium-ion battery with a reference electrode.

[0030] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. A method for evaluating the limiting capacity electrode of a lithium-ion battery provided by the present invention adopts a three-electrode synchronous measurement technique to quickly obtain the specific capacities utilized by the positive electrode and the negative electrode of the lithium-ion battery with a reference electrode.

[0032] 2. A method for evaluating the limiting capacity electrode of a lithium-ion battery provided by the present invention evaluates the limiting capacity electrode of the lithium-ion battery by comparing the magnitudes of the ratios of the specific capacities of the positive and negative electrode materials in the full charge balance potential curves to the specific capacities utilized by the corresponding electrodes of the lithium-ion battery with a reference electrode, getting rid of the traditional cumbersome detection and evaluation methods. Description of the Drawings

[0033] Figure 1This is a flow chart of the method for evaluating the limited capacity electrode of a lithium ion battery of the present invention;

[0034] Figure 2 is a complete charge equilibrium potential curve of the positive electrode material of the present invention;

[0035] Figure 3 is a complete discharge equilibrium potential curve of the negative electrode material of the present invention;

[0036] Figure 4 It is the local equilibrium potential curve of the positive electrode and the negative electrode of the lithium ion battery of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the attached Figures 1 to 4 , the technical content, structural features, objectives achieved and effects of the present invention are described in detail through preferred embodiments.

[0038] It should be noted that the drawings are in a very simplified form and use non-precise proportions. They are only used to conveniently and clearly assist in explaining the embodiments of the present invention, and are not used to limit the conditions for the implementation of the present invention. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention.

[0039] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] The present invention provides a method for evaluating a limited capacity electrode of a lithium ion battery. Figure 1 As shown, the lithium-ion battery limited capacity electrode evaluation method includes:

[0042] S1, obtaining a positive electrode complete charge equilibrium potential curve and a negative electrode complete discharge equilibrium potential curve of a standard lithium-ion battery;

[0043] S2, assembling a lithium-ion battery with a reference electrode, and measuring the potential of the lithium-ion battery with the reference electrode to obtain a local equilibrium potential curve of the positive electrode and a local equilibrium potential curve of the negative electrode;

[0044] S3, performing limited capacity electrode evaluation on the lithium ion battery having the reference electrode.

[0045] Wherein, the step S1 comprises:

[0046] S1.1, preparing a first standard button cell comprising a standard lithium-ion battery positive electrode and a second standard button cell comprising a standard lithium-ion battery negative electrode.

[0047] The standard lithium-ion battery positive electrode comprises: a positive electrode active material, a conductive agent and a binder.

[0048] The preparation process of the standard lithium-ion battery positive electrode is as follows: the positive electrode active material: conductive agent: binder are weighed according to a weight ratio of 8:1:1, and then mixed and added into an N-methylpyrrolidone solvent for dissolution to form a slurry, and then the slurry is coated on a metal foil current collector, and is dried, rolled, and punched to form a positive electrode material disc with a diameter of 10 mm to 14 mm, and finally assembled in an argon atmosphere of a glove box to form a first standard button battery with a standard lithium-ion battery positive electrode.

[0049] Among them, the positive electrode active material in the positive electrode of the lithium-ion battery is one or more of nickel-cobalt-manganese material, lithium cobalt oxide material, nickel-cobalt-aluminum material, and nickel-cobalt-manganese oxide lithium material; in a specific embodiment of the present invention, nickel-cobalt-manganese oxide lithium material is used as the positive electrode active material.

[0050] Furthermore, the nickel cobalt manganese oxide lithium material exhibits a sloping platform on the charge and discharge voltage platform, that is, there is a sloping change in the specific capacity-voltage curve.

[0051] In a specific embodiment of the present invention, the positive electrode material disc is made with a diameter of Φ10 mm.

[0052] Specifically, the first standard button battery is a 2016 button battery.

[0053] The standard lithium-ion battery negative electrode comprises: a negative electrode active material, a conductive agent and a binder.

[0054] The preparation process of the standard lithium-ion battery negative electrode is as follows: the negative electrode active material: conductive agent: binder are weighed according to a weight ratio of 8:1:1, and then mixed and added into an N-methylpyrrolidone solvent for dissolution to form a slurry, and then the slurry is coated on a metal foil current collector, and is dried, rolled, and punched to form a negative electrode material disc with a diameter of 10 mm to 14 mm, and finally assembled in an argon atmosphere of a glove box to form a second standard button battery with a standard lithium-ion battery negative electrode.

[0055] The negative electrode active material in the negative electrode of the lithium-ion battery is one or more of niobium oxide, niobium titanium oxide, and lithium yttrium titanate. In a specific embodiment of the present invention, niobium titanium oxide material is used as the negative electrode active material.

[0056] Furthermore, the niobium titanium oxide material exhibits a sloping platform on the charge-discharge voltage platform, that is, there is a slope change in the specific capacity-voltage curve.

[0057] In a specific embodiment of the present invention, the negative electrode material disc is made with a diameter of Φ10 mm.

[0058] Specifically, the second standard button battery is a 2016 button battery.

[0059] S1.2, charging and discharging the first standard button battery and the second standard button battery respectively to obtain a complete charging equilibrium potential curve of the positive electrode and a complete discharging equilibrium potential curve of the negative electrode of the standard lithium-ion battery.

[0060] Specifically, the first standard button cell is charged from 0% SOC (battery charge ratio) to 100% SOC at a constant current, and the following is obtained: Figure 2 The complete charge equilibrium potential curve of the standard lithium-ion battery positive electrode shown is the specific capacity-voltage curve of the standard lithium-ion battery positive electrode, and the first cut-off voltage and the corresponding first specific capacity value are obtained. The figure shows that when the first cut-off voltage of the standard lithium-ion battery positive electrode is 4.3V, the corresponding first specific capacity value is 207.8mAh / g.

[0061] Wherein, the charging method is one of current titration charging, voltage titration charging or small rate constant current charging.

[0062] In a specific embodiment of the present invention, a small rate constant current charging method is adopted, and the charging rate is 0.01C to 0.1C; in this embodiment, the charging rate is specifically 0.05C.

[0063] Specifically, the second standard button cell is discharged from 0% SOC (battery charge ratio) to 100% SOC at a constant current to obtain the following Figure 3The complete discharge equilibrium potential curve of the negative electrode of the standard lithium-ion battery shown is the specific capacity-voltage curve of the negative electrode of the standard lithium-ion battery, and the second cut-off potential and the corresponding second specific capacity value are obtained. The figure shows that when the second cut-off potential of the negative electrode of the standard lithium-ion battery is 1.1V, the corresponding second specific capacity value is 234.8mAh / g.

[0064] Wherein, the discharge mode is one of current titration discharge, voltage titration discharge or small rate constant current discharge.

[0065] In a specific embodiment of the present invention, a small rate constant current discharge mode is adopted for charging, and the charging rate is 0.01C to 0.1C; in this embodiment, the discharge rate is specifically 0.05C.

[0066] Wherein, the step S2 comprises:

[0067] S2.1, inserting lithium-plated copper wire or lithium metal between the positive electrode and the negative electrode of another prepared lithium-ion battery to form a lithium-ion battery with a reference electrode to accurately measure the electrochemical process occurring inside the lithium-ion battery.

[0068] Among them, the positive electrode material of the lithium-ion battery with a reference electrode is one or more of nickel-cobalt-manganese material, lithium cobalt oxide material, nickel-cobalt-aluminum material, and nickel-cobalt-manganese oxide lithium material; in a specific embodiment of the present invention, nickel-cobalt-manganese oxide lithium material is used as the positive electrode material of the lithium-ion battery.

[0069] Among them, the negative electrode material of the lithium ion battery with a reference electrode is one or more of niobium oxide, niobium titanium oxide, and lithium yttrium titanate materials; in a specific embodiment of the present invention, niobium titanium oxide material is used as the negative electrode material of the lithium ion battery.

[0070] S2.2, using three-electrode synchronous testing technology, in-situ measurement is performed on the lithium-ion battery with the reference electrode to simultaneously obtain the positive electrode local equilibrium potential curve and the negative electrode local equilibrium potential curve.

[0071] Specifically, the lithium-ion battery with the reference electrode is charged from 0% SOC to 100% SOC at a constant current, with a charging cut-off voltage of 3V, and the following are obtained simultaneously through the three-electrode synchronous testing technology: Figure 4 The positive electrode local equilibrium potential curve and the negative electrode local equilibrium potential curve of the lithium ion battery with a reference electrode are shown.

[0072] The charging method is one of current titration charging, voltage titration charging or small rate constant current charging.

[0073] Specifically, the charging rate range for low-rate constant current charging is 0.01C to 0.1C; in a specific embodiment of the present invention, charging is performed using a low-rate constant current charging method with a rate of 0.05C.

[0074] Among them, the step S3 includes:

[0075] S3.1, obtaining the specific capacity value utilized by the positive electrode of the lithium-ion battery with a reference electrode and the specific capacity value utilized by the negative electrode of the lithium-ion battery.

[0076] S3.1.1, from the local equilibrium potential curve graph, obtaining that the highest voltage value of the positive electrode of the lithium-ion battery with a reference electrode is 4.15V, and the lowest voltage value of the negative electrode of the lithium-ion battery with a reference electrode is 1.15V;

[0077] S3.1.2, from Figure 2 the complete charging equilibrium potential curve of the shown standard lithium-ion battery positive electrode, reading the specific capacity value corresponding to the highest voltage value of 4.15V as 176.1mAh / g, that is, the specific capacity utilized by the positive electrode of the lithium-ion battery with a reference electrode is 176.1mAh / g;

[0078] From Figure 3 the complete discharging equilibrium potential curve of the shown standard lithium-ion battery negative electrode, reading the specific capacity value corresponding to the lowest voltage value of 1.15V as 228.1mAh / g, that is, the specific capacity utilized by the negative electrode of the lithium-ion battery with a reference electrode is 228.1mAh / g.

[0079] S3.2, calculating the ratio M of the first specific capacity (207.8mAh / g) of the standard lithium-ion battery positive electrode under complete charging equilibrium to the specific capacity (176.1mAh / g) utilized by the positive electrode of the lithium-ion battery with a reference electrode, obtaining M as 1.18; calculating the ratio m of the second specific capacity (234.8mAh / g) of the standard lithium-ion battery negative electrode under complete discharging equilibrium to the specific capacity (228.1mAh / g) utilized by the negative electrode of the lithium-ion battery with a reference electrode, obtaining m as 1.029.

[0080] S3.3, by comparing the magnitudes of M and m, determining whether the limiting capacity electrode of the lithium-ion battery with a reference electrode is the positive electrode or the negative electrode.

[0081] If M>m, then the negative electrode of the lithium-ion battery is the limiting capacity electrode; if M<m, then the positive electrode of the lithium-ion battery is the limiting capacity electrode.

[0082] Specifically, M = 1.18, m = 1.029, so M>m, then the negative electrode of the lithium-ion battery is the limiting capacity electrode; further, in a specific embodiment of the present invention, it is obtained that the negative electrode using niobium titanium oxide is the limiting capacity electrode.

[0083] In summary, the present invention provides a method for evaluating a limited-capacity electrode for a lithium-ion battery, which utilizes a three-electrode synchronous measurement technique to quickly obtain the specific capacity utilized by the positive and negative electrodes of a lithium-ion battery with a reference electrode, thereby calculating the ratio of the specific capacity of the complete charging equilibrium potential curve of the positive and negative electrode materials to the specific capacity utilized by the corresponding electrodes of the lithium-ion battery with the reference electrode, thereby realizing the evaluation of the limited-capacity electrode for the lithium-ion battery, thereby guiding the lithium-ion battery preparation process and optimizing it.

[0084] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the invention. After reading the above content, it will be obvious to those skilled in the art for various modifications and substitutions of the present invention. Therefore, the protection scope of the present invention should be limited by the attached claims.

Claims

1. A method for evaluating a limited capacity electrode for a lithium ion battery, characterized in that: Include: S1, obtaining a positive electrode complete charge equilibrium potential curve and a negative electrode complete discharge equilibrium potential curve of a standard lithium-ion battery; S2, assembling a lithium-ion battery with a reference electrode, and measuring the potential of the lithium-ion battery with the reference electrode to obtain a local equilibrium potential curve of the positive electrode and a local equilibrium potential curve of the negative electrode; S3, performing limited capacity electrode evaluation on the lithium ion battery having the reference electrode.

2. The method for evaluating a lithium-ion battery limited capacity electrode according to claim 1, wherein: The step S1 comprises: S1.1, preparing a first standard button cell comprising a standard lithium ion battery positive electrode and a second standard button cell comprising a standard lithium ion battery negative electrode; S1.2, charging and discharging the first standard button battery and the second standard button battery respectively to obtain a complete charging equilibrium potential curve of the positive electrode and a complete discharging equilibrium potential curve of the negative electrode of the standard lithium-ion battery.

3. The method for evaluating a lithium-ion battery limited capacity electrode according to claim 2, wherein: The standard lithium-ion battery positive electrode comprises: a positive electrode active material, a conductive agent and a binder; and the weight ratio of the positive electrode active material, the conductive agent and the binder is 8:1:1; The standard lithium-ion battery negative electrode comprises: a negative electrode active material, a conductive agent and a binder; and The weight ratio of the negative electrode active material, the conductive agent and the binder is 8:1:

1.

4. The method for evaluating a lithium-ion battery limited capacity electrode according to claim 3, wherein: The positive electrode active material is one or more of nickel cobalt manganese material, lithium cobalt oxide material, nickel cobalt aluminum material, and nickel cobalt manganese oxide lithium material; the negative electrode active material is one or more of niobium oxide, niobium titanium oxide, and lithium yttrium titanate material.

5. The method for evaluating a lithium-ion battery limited capacity electrode according to claim 2, wherein: A first cut-off voltage and a corresponding first specific capacity value are obtained from the complete charge equilibrium potential curve of the positive electrode of the standard lithium ion battery; and a second cut-off voltage and a corresponding second specific capacity value are obtained from the complete discharge equilibrium potential curve of the negative electrode of the standard lithium ion battery.

6. The method for evaluating a lithium-ion battery limited capacity electrode according to claim 5, characterized in that: The step S2 comprises: S2.1, inserting a lithium-plated copper wire or lithium metal between the positive electrode and the negative electrode of another lithium-ion battery to form a lithium-ion battery with a reference electrode; S2.2, using a three-electrode synchronous testing technique, to perform in-situ measurement on the lithium-ion battery having a reference electrode, so as to simultaneously obtain the local equilibrium potential curve of the positive electrode and the local equilibrium potential curve of the negative electrode of the battery.

7. The method for evaluating a lithium-ion battery limited capacity electrode according to claim 6, wherein: The positive electrode material of the lithium-ion battery with a reference electrode is one or more of nickel-cobalt-manganese material, lithium cobalt oxide material, nickel-cobalt-aluminum material, and nickel-cobalt-manganese oxide lithium material; the negative electrode material of the lithium-ion battery with a reference electrode is one or more of niobium oxide, niobium-titanium oxide, and lithium yttrium titanate material.

8. The method for evaluating a lithium-ion battery limited capacity electrode according to claim 6, wherein: The step S3 comprises: S3.1, obtaining the specific capacity value utilized by the positive electrode and the specific capacity value utilized by the negative electrode of the lithium ion battery having the reference electrode; S3.2, calculating the ratio M of the first specific capacity of the positive electrode of the standard lithium ion battery under complete charge balance to the specific capacity used by the positive electrode of the lithium ion battery with the reference electrode; and calculating the ratio m of the second specific capacity of the negative electrode of the standard lithium ion battery under complete discharge balance to the specific capacity used by the negative electrode of the lithium ion battery with the reference electrode; S3.3, by comparing the sizes of M and m, determine whether the capacity-limiting electrode of the lithium-ion battery with the reference electrode is the positive electrode or the negative electrode.

9. The method for evaluating a lithium-ion battery limited capacity electrode according to claim 8, wherein: If M > m, the negative electrode of the lithium-ion battery with a reference electrode is a capacity-limiting electrode; if M < m, the positive electrode of the lithium-ion battery with a reference electrode is a capacity-limiting electrode.

10. The method for evaluating a lithium-ion battery limited capacity electrode according to claim 8, wherein: The step S3.1 includes: Obtaining the highest voltage value of the positive electrode and the lowest voltage value of the negative electrode of the lithium-ion battery with a reference electrode from the local equilibrium potential curve diagram; Reading the specific capacity corresponding to the highest voltage value from the complete charge equilibrium potential curve of the positive electrode of the standard lithium-ion battery, and this specific capacity is the specific capacity utilized by the positive electrode of the lithium-ion battery with a reference electrode; Reading the specific capacity corresponding to the lowest voltage value from the complete discharge equilibrium potential curve of the negative electrode of the quasi-lithium-ion battery, and this specific capacity is the specific capacity utilized by the negative electrode of the lithium-ion battery with a reference electrode.

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