Method for manufacturing non-aqueous electrolyte storage element

Abstract

SOLUTION: To provide a method for manufacturing a non-aqueous electrolyte storage element including: removing an electrode from a recovered non-aqueous electrolyte storage element including an electrode having a substrate and an active material layer disposed on the substrate, performing treatment for adjusting the charge transport ion content of the electrode before or after removing the electrode, and assembling a new non-aqueous electrolyte storage element including the electrode that has been subjected to the adjustment treatment, and in which the active material layer includes an active material consisting of secondary particles or substantially non-aggregated primary particles having a ratio of an average particle size to an average primary particle size of 3 or less.EFFECT: The electrodes of a recovered non-aqueous electrolyte storage element can be reused as they are to obtain a new non-aqueous electrolyte storage element with sufficient performance.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a non-aqueous electrolyte storage element.

Background Art

[0002] Non-aqueous electrolyte secondary batteries typified by lithium-ion secondary batteries are widely used in electronic devices such as personal computers and communication terminals, and automobiles, etc. due to their high energy density. A non-aqueous electrolyte secondary battery generally has a pair of electrodes electrically isolated by a separator and a non-aqueous electrolyte interposed between the electrodes, and is configured to charge and discharge by transferring charge-transporting ions between both electrodes. Further, as non-aqueous electrolyte storage elements other than non-aqueous electrolyte secondary batteries, capacitors such as lithium-ion capacitors and electric double layer capacitors are also widely popular.

[0003] With the expansion of the market for non-aqueous electrolyte storage elements, the development of recycling methods for used non-aqueous electrolyte storage elements, etc. is being promoted. As a recycling method for non-aqueous electrolyte storage elements, a method also called direct recycling, etc. is being studied, in which an active material is taken out from the electrodes of a non-aqueous electrolyte storage element and reused as an active material without performing dissolution of the taken-out active material, decomposition into raw material compounds containing constituent elements, etc. (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The direct recycling of the active material is considered to be able to recycle at low cost and efficiently as compared with the method of newly synthesizing the active material using the active material taken out from the electrode. Here, in order to reuse the recovered non-aqueous electrolyte storage element more efficiently, it is desirable to reuse the electrode as it is without even taking out the active material from the electrode. However, when the electrode provided in the recovered non-aqueous electrolyte storage element is reused as it is, there are cases where the non-aqueous electrolyte storage element using such an electrode cannot ensure sufficient performance.

[0006] An object of the present invention is to provide a method for manufacturing a non-aqueous electrolyte storage element capable of obtaining a new non-aqueous electrolyte storage element in which the electrode provided in the recovered non-aqueous electrolyte storage element is reused as it is and sufficient performance is ensured.

Means for Solving the Problems

[0007] A method for manufacturing a non-aqueous electrolyte storage element according to one aspect of the present invention includes removing the electrode from a recovered non-aqueous electrolyte storage element including a base material and an electrode having an active material layer disposed on the base material, and before or after removing the electrode, performing an adjustment process on the electrode for the charge transport ion content, and assembling a new non-aqueous electrolyte storage element including the electrode on which the adjustment process has been performed, wherein the active material layer includes secondary particles having a ratio of the average particle diameter to the average primary particle diameter of 3 or less, or an active material composed of substantially non-aggregated primary particles.

Effects of the Invention

[0008] According to one aspect of the present invention, it is possible to provide a method for manufacturing a non-aqueous electrolyte storage element capable of obtaining a new non-aqueous electrolyte storage element in which the electrode provided in the recovered non-aqueous electrolyte storage element is reused as it is and sufficient performance is ensured.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0010] First, an outline of a method for manufacturing a non-aqueous electrolyte storage element disclosed in this specification will be described.

[0011] (1) The method for manufacturing a non-aqueous electrolyte storage element according to one aspect of the present invention includes removing the electrode from a recovered non-aqueous electrolyte storage element including a base material and an electrode having an active material layer disposed on the base material, performing an adjustment process on the charge transport ion content of the electrode before or after removing the electrode, and assembling a new non-aqueous electrolyte storage element including the electrode on which the adjustment process has been performed. The active material layer includes an active material composed of secondary particles having a ratio of the average particle diameter to the average primary particle diameter of 3 or less, or primary particles that are not substantially aggregated.

[0012] According to the method for manufacturing a non-aqueous electrolyte storage element described in (1) above, a new non-aqueous electrolyte storage element with sufficient performance can be obtained by directly reusing the electrodes provided in the recovered non-aqueous electrolyte storage element. Although the reason for this is not clear, the following reasons are speculated. By performing an adjustment process on the charge transport ion content of the electrodes of the recovered non-aqueous electrolyte storage element and incorporating these electrodes into a new non-aqueous electrolyte storage element without removing the active material from the electrodes, it is possible to directly reuse the electrodes. However, when the active material used in the electrodes of the non-aqueous electrolyte storage element is secondary particles, cracking (and thus isolation due to cracking) is likely to occur due to repeated expansion and contraction during charge and discharge. Cracking of the active material reduces the performance of the active material due to a decrease in electron conductivity, etc. Also, even if an adjustment process for the charge transport ion content is performed, a decrease in electron conductivity due to particle cracking, etc. may have an impact, and there may be cases where the charge transport ion content cannot be adjusted to an appropriate amount. Therefore, when the active material used in the electrodes of the recovered non-aqueous electrolyte storage element is secondary particles, it is difficult to exhibit sufficient performance as a non-aqueous electrolyte storage element when these electrodes are directly incorporated into a new non-aqueous electrolyte. For example, in a non-aqueous electrolyte storage element using an active material with severe cracking, the discharge capacity, etc., especially when performing charge and discharge at a high current density, tends to be insufficient. On the other hand, secondary particles with a ratio of the average particle diameter to the average primary particle diameter of 3 or less, or primary particles that are not substantially aggregated (hereinafter, secondary particles with a ratio of the average particle diameter to the average primary particle diameter of 3 or less, or primary particles that are not substantially aggregated are also referred to as "single-particle system particles") are less likely to crack due to repeated charge and discharge. In the method for manufacturing a non-aqueous electrolyte storage element described in (1) above, since the electrodes of the recovered non-aqueous electrolyte storage element contain an active material composed of single-particle system particles, by performing an adjustment process on the charge transport ion content of these electrodes and incorporating these electrodes into a new non-aqueous electrolyte storage element without removing the active material from the electrodes, a new non-aqueous electrolyte storage element with sufficient performance can be obtained by directly reusing the electrodes.

[0013] "Secondary particles" refer to particles formed by the aggregation of a plurality of primary particles. "Primary particles" refer to particles in which no grain boundaries are observed on the surface when observed with a scanning electron microscope (SEM). The "average primary particle diameter" of the active material is the average value of the primary particle diameters of any 50 primary particles constituting the active material observed by SEM. The primary particle diameter of a primary particle is determined as follows. The shortest diameter passing through the center of the minimum circumscribed circle of the primary particle is defined as the minor axis, and the diameter passing through the center and perpendicular to the minor axis is defined as the major axis. The average value of the major axis and the minor axis is defined as the particle diameter. When there are two or more shortest diameters, the diameter that is perpendicular and the longest is defined as the minor axis. The "average particle diameter" of the active material is the value (D50: median diameter) at which the volume-based cumulative distribution calculated in accordance with JIS-Z-8819-2 (2001) based on the particle size distribution measured by the laser diffraction / scattering method for a dilution obtained by diluting the active material with a solvent in accordance with JIS-Z-8815 (2013) is 50%. It has been confirmed that the average particle diameter based on the above measurement is almost the same as the average particle diameter, which is the average value of the particle diameters (secondary particle diameters) of 50 particles extracted while avoiding extremely large and extremely small particles from the SEM image of the particles. The average particle diameter of each secondary particle based on the measurement from this SEM image is determined as follows. Based on the SEM image, the shortest diameter passing through the center of the minimum circumscribed circle of each secondary particle is defined as the minor axis, and the diameter passing through the center and perpendicular to the minor axis is defined as the major axis. The average value of the major axis and the minor axis is defined as the average particle diameter of each secondary particle. When there are two or more shortest diameters, the diameter that is perpendicular and the longest is defined as the minor axis. "Primary particles that are not substantially aggregated" refer to primary particles that exist independently without aggregation of a plurality of primary particles when observed by SEM, or primary particles in a state where the primary particles and other primary particles are generally not directly bonded. The average primary particle diameter and average particle diameter of the active material incorporated in the electrode of the non-aqueous electrolyte storage element are the values in the state where the non-aqueous electrolyte storage element is charged at a constant current with a charging current of 0.05C until the charging end voltage during normal use, rested for 30 minutes, and then discharged at a constant current with a discharging current of 0.05C until the discharging end voltage during normal use. "During normal use" means the case where the non-aqueous electrolyte storage element is used by adopting the charge-discharge conditions recommended or specified for the non-aqueous electrolyte storage element. For example, when a device for using the non-aqueous electrolyte storage element is prepared, it may also be the case where the non-aqueous electrolyte storage element is used by applying that device.

[0014] (2) In the method for manufacturing the non-aqueous electrolyte storage element according to (1) above, it may further include pressing the taken-out electrode in the thickness direction.

[0015] According to the method for manufacturing the non-aqueous electrolyte storage element described in (2) above, by pressing the taken-out electrode in the thickness direction, the contact area between the active material particles, between the active material and the base material, etc. is enlarged, so that the performance of the obtained new non-aqueous electrolyte storage element can be improved, etc.

[0016] The "thickness direction" of the electrode means the direction in which the base material and the active material layer are laminated. In other words, the "thickness direction" of the electrode is the direction perpendicular to the surface of the active material layer and is also the thickness direction of the active material layer.

[0017] (3) In the method for manufacturing the non-aqueous electrolyte storage element according to (1) or (2) above, it may include cutting the taken-out electrode and manufacturing an electrode body having the cut electrode.

[0018] According to the method for manufacturing a non-aqueous electrolyte storage element described in (3) above, it is possible to manufacture a new non-aqueous electrolyte storage element including an electrode body having a shape, size, etc. different from those of the recovered non-aqueous electrolyte storage element. Further, according to the method for manufacturing a non-aqueous electrolyte storage element described in (3) above, for example, by removing a portion not suitable for reuse from the electrode of the recovered non-aqueous electrolyte storage element by cutting, etc., the performance of the obtained new non-aqueous electrolyte storage element can be sufficiently enhanced.

[0019] (4) In the method for manufacturing a non-aqueous electrolyte storage element according to any one of (1) to (3) above, when the electrode is a positive electrode, the adjustment process may be at least one of discharging the recovered non-aqueous electrolyte storage element and fabricating a single cell by combining the taken-out electrode and a counter electrode capable of releasing charge-transporting ions and discharging the single cell.

[0020] According to the method for manufacturing a non-aqueous electrolyte storage element described in (4) above, charge-transporting ions can be efficiently filled into the active material (positive electrode active material) provided in the positive electrode, and the performance of the obtained new non-aqueous electrolyte storage element can be sufficiently enhanced, etc.

[0021] (5) In the method for manufacturing a non-aqueous electrolyte storage element according to any one of (1) to (4) above, it may include confirming that the recovered non-aqueous electrolyte storage element contains an active material composed of secondary particles having a ratio of the average particle diameter to the average primary particle diameter of 3 or less, or primary particles that are not substantially aggregated, in the active material layer.

[0022] According to the method for manufacturing a non-aqueous electrolyte storage element described in (5) above, by confirming that a single-particle-based particle active material is used in the recovered non-aqueous electrolyte storage element to be reused, it is possible to reliably obtain a new non-aqueous electrolyte storage element with sufficient performance ensured.

[0023] (6) In the method for manufacturing a non-aqueous electrolyte storage element according to any one of (1) to (5) above, the active material may contain a lithium transition metal composite oxide.

[0024] Lithium transition metal composite oxides are generally often used as active materials in the form of secondary particles, and are also prone to cracking during charge and discharge. For this reason, usually, it is difficult to directly reuse an electrode using a lithium transition metal composite oxide to obtain a new non-aqueous electrolyte storage element with sufficient performance. On the other hand, the method for manufacturing a non-aqueous electrolyte storage element described in the above (6), in which an electrode using a lithium transition metal composite oxide as an active material is directly reused, particularly significantly obtains the advantage of the present invention that a new non-aqueous electrolyte storage element with sufficient performance can be obtained.

[0025] (7) In the method for manufacturing a non-aqueous electrolyte storage element according to any one of the above (1) to (6), the active material may contain a lithium nickel cobalt manganese composite oxide.

[0026] Lithium nickel cobalt manganese composite oxides, among lithium transition metal composite oxides in particular, are generally often used as active materials in the form of secondary particles, and are also prone to cracking during charge and discharge. For this reason, usually, it is difficult to directly reuse an electrode using a lithium nickel cobalt manganese composite oxide to obtain a new non-aqueous electrolyte storage element with sufficient performance. On the other hand, the method for manufacturing a non-aqueous electrolyte storage element described in the above (7), in which an electrode using a lithium nickel cobalt manganese composite oxide as an active material is directly reused, particularly significantly obtains the advantage of the present invention that a new non-aqueous electrolyte storage element with sufficient performance can be obtained.

[0027] (8) In the method for manufacturing a non-aqueous electrolyte storage element according to any one of the above (1) to (7), the average primary particle diameter of the active material may be 1 μm or more and 10 μm or less.

[0028] According to the method for manufacturing a non-aqueous electrolyte storage element described in the above (8), the average primary particle diameter of the active material is sufficiently large, and a new non-aqueous electrolyte storage element with more sufficient performance can be obtained.

[0029] A method for manufacturing a non-aqueous electrolyte storage element according to an embodiment of the present invention and other embodiments will be described in detail. Note that the names of the constituent members (each component) used in each embodiment may be different from the names of the constituent members (each component) used in the background art.

[0030] <Method for manufacturing a non-aqueous electrolyte storage element> A method for manufacturing a non-aqueous electrolyte storage element according to an embodiment of the present invention includes removing the electrode from a recovered non-aqueous electrolyte storage element including a base material and an electrode having an active material layer disposed on the base material (hereinafter, also referred to as "electrode removal S2"), performing an adjustment process on the electrode for adjusting the charge transport ion content before or after removing the electrode (hereinafter, also referred to as "adjustment process S3"), and assembling a new non-aqueous electrolyte storage element including the electrode on which the adjustment process has been performed (hereinafter, also referred to as "assembly S7"). In the recovered non-aqueous electrolyte storage element to be reused, the active material layer contains an active material composed of single-particle system particles.

[0031] As an optional step, the manufacturing method may further include confirming that the recovered non-aqueous electrolyte storage element contains an active material composed of single-particle system particles in the active material layer (hereinafter, also referred to as "confirmation S1"), pressing the removed electrode in the thickness direction (hereinafter, also referred to as "pressing S4"), cutting the removed electrode (hereinafter, also referred to as "cutting S5"), and producing an electrode body including the removed electrode (hereinafter, also referred to as "electrode body production S6").

[0032] The manufacturing method does not newly synthesize an active material using the active material contained in the electrodes of the recovered non-aqueous electrolyte storage element as a raw material. That is, the manufacturing method directly recycles the active material. Further, in this manufacturing method, without removing the active material from the electrodes of the recovered non-aqueous electrolyte storage element and without separating the base material and the active material layer, the electrodes are reused as they are to manufacture a new non-aqueous electrolyte storage element. Therefore, this manufacturing method is a low-cost and efficient recycling method for non-aqueous electrolyte storage elements.

[0033] In the manufacturing method of a non-aqueous electrolyte storage element according to an embodiment of the present invention, the recovered non-aqueous electrolyte storage element is a non-aqueous electrolyte storage element that has been recovered and is to be reused. Examples of such recovered non-aqueous electrolyte storage elements (non-aqueous electrolyte storage elements to be reused) include those recovered as used products, those recovered as unused products after shipment, and those recovered as defective products during manufacturing. Further, the electrodes to be reused may be either the positive electrode or the negative electrode as long as they contain an active material composed of single-particle system particles. Both the positive electrode and the negative electrode provided in the recovered non-aqueous electrolyte storage element may be reused. The electrode has a base material and an active material layer disposed directly on the base material or via an intermediate layer. Usually, an active material is contained in the active material layer together with optional components such as a binder and a conductive agent. When the electrode is a positive electrode, the base material is also referred to as a positive electrode base material, and the active material layer is also referred to as a positive electrode active material layer. When the electrode is a negative electrode, the base material is also referred to as a negative electrode base material, and the active material layer is also referred to as a negative electrode active material layer.

[0034] In the active material composed of single-particle system particles contained in the active material layer of the electrode to be reused, the ratio of the average particle diameter to the average primary particle diameter is 3 or less, preferably 2.5 or less, and more preferably 2 or less. The ratio of the average particle diameter to the average primary particle diameter of the single-particle system particles is preferably 1 or more. Note that due to the difference in the measurement methods of the average primary particle diameter and the average particle diameter, the ratio of the average particle diameter to the average primary particle diameter may be less than 1.

[0035] The average primary particle diameter of the active material composed of single-particle system particles is not particularly limited, and may be, for example, 0.1 μm or more and 20 μm or less, but preferably 1 μm or more and 10 μm or less. The lower limit of the average primary particle diameter may be 2 μm, 3 μm, or 5 μm. The upper limit of the average primary particle diameter may be 8 μm, 6 μm, or 4 μm. By having the average primary particle diameter of the single-particle system particles within the above range, a new non-aqueous electrolyte storage element with more sufficient performance can be obtained.

[0036] The active material layer of the electrode to be reused may contain an active material other than the active material composed of single-particle system particles. The content of the active material composed of single-particle system particles with respect to all the active materials in the active material layer of the electrode to be reused is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, still more preferably 90% by mass or more and 100% by mass or less, even more preferably 95% by mass or more and 100% by mass or less, and particularly preferably 100% by mass.

[0037] In one embodiment of the present invention, the electrode to be reused may be a positive electrode. From the perspective of cost-effectiveness of reuse, etc., the active material of the positive electrode to be reused preferably contains a compound containing a rare metal element such as a lithium element, a nickel element, a cobalt element, or a manganese element. The active material of the positive electrode to be reused is preferably, for example, a lithium transition metal composite oxide, and more preferably a lithium nickel cobalt manganese composite oxide. Specific forms of the recovered non-aqueous electrolyte storage element, electrode, active material, etc. to be reused in the manufacturing method will be described in detail later.

[0038] Hereinafter, each step of the manufacturing method of the non-aqueous electrolyte storage element according to one embodiment of the present invention will be described with reference to FIG. 1. Note that FIG. 1 shows the process order as an example in the manufacturing method as a flow chart. The manufacturing method is not limited to the process order of FIG. 1. Also, as described above, the steps other than the extraction S2, adjustment process S3, and assembly S7 of the electrode are optional steps.

[0039] (Confirmation S1) In this process, it is confirmed that the recovered non-aqueous electrolyte storage element contains an active material composed of single-particle system particles in the active material layer to be reused. As a method for this confirmation, a method of confirming by the model number or the like of the recovered non-aqueous electrolyte storage element can be mentioned. From the model number or the like of the recovered non-aqueous electrolyte storage element, the factory where it was manufactured, the time, the raw materials, etc. can be specified, and it can be mentioned that it is confirmed whether an active material composed of single-particle system particles is used. In addition, the recovered non-aqueous electrolyte storage element may be disassembled and the active material may be directly analyzed to confirm whether it contains an active material composed of single-particle system particles. In this process, if the recovered non-aqueous electrolyte storage element does not contain an active material composed of single-particle system particles in the active material layer, the recovered non-aqueous electrolyte storage element can be reused, disposed of, etc. by another method different from the method for manufacturing a non-aqueous electrolyte storage element according to an embodiment of the present invention.

[0040] (Electrode extraction S2) In this process, an electrode having an active material layer containing an active material composed of single-particle system particles is taken out from the recovered non-aqueous electrolyte storage element. The extraction of the electrode can be performed by disassembling the recovered non-aqueous electrolyte storage element by a known method or the like. The extracted electrode may or may not be subjected to treatments such as washing and drying. As will be described later, an adjustment process S3 may be performed before the electrode extraction S2. In addition, when only one of the positive electrode and the negative electrode is used in the method for manufacturing a non-aqueous electrolyte storage element of the present embodiment, the other electrode may be reused by another method different from the method for manufacturing a non-aqueous electrolyte storage element according to an embodiment of the present invention, or a process other than reuse may be performed.

[0041] (Adjustment process S3) In this process, an adjustment process for the charge transport ion content is performed on an electrode having an active material layer containing an active material composed of single-particle system particles. This adjustment process S3 may be performed before the electrode extraction S2 or after the electrode extraction S2. When the adjustment process S3 is performed before the electrode extraction S2, for example, it can be performed between the confirmation S1 and the electrode extraction S2.

[0042] In the recovered non-aqueous electrolyte storage element used, the content of charge transport ions such as lithium ions in the positive electrode active material may be low, and the content of charge transport ions in the negative electrode active material may be excessive. Therefore, when reusing the positive electrode, usually, as the adjustment process S3, a process of filling the positive electrode active material with charge transport ions is performed. On the other hand, when reusing the negative electrode, usually, as the adjustment process S3, a process of discharging charge transport ions from the negative electrode active material is performed.

[0043] The adjustment process S3 can be performed, for example, by discharging the recovered non-aqueous electrolyte storage element before the extraction S2 of the electrode. As the discharge of the recovered non-aqueous electrolyte storage element, it is preferable to perform constant voltage discharge after constant current discharge, and it is more preferable to perform constant voltage discharge with the lower limit SOC set to 0% after constant current discharge. That is, it is more preferable to perform discharge within a range where the SOC does not become less than 0%. By performing discharge within a range where the SOC does not become less than 0%, elution of metals contained in the negative electrode substrate such as copper as ions into the non-aqueous electrolyte can be suppressed. Further, it is more preferable to perform constant voltage discharge with the lower limit SOC set to 0%. By performing constant voltage discharge with the lower limit SOC set to 0%, while suppressing elution of metals contained in the negative electrode substrate as ions into the non-aqueous electrolyte, the amount by which the content of charge transport ions is adjusted can be increased. SOC (State of Charge) represents the charging rate of the non-aqueous electrolyte storage element based on the rated capacity. By performing the above-described discharge on the recovered non-aqueous electrolyte storage element, charge transport ions are discharged from the negative electrode active material and the positive electrode active material is filled with charge transport ions. Thereby, in both the positive electrode and the negative electrode, the content of charge transport ions can be adjusted to an appropriate amount.

[0044] The adjustment process S3 can also be performed by fabricating a single cell by combining, for example, a positive electrode which is an electrode taken out by the electrode extraction S2 and a counter electrode (negative electrode) capable of releasing charge-transporting ions, and discharging the single cell. When the recovered non-aqueous electrolyte storage element is, for example, a lithium-ion secondary battery, as the counter electrode capable of releasing charge-transporting ions, a counter electrode having metallic lithium can be used as the counter electrode capable of releasing lithium ions. By discharging the single cell, charge-transporting ions are released from the counter electrode and the positive electrode active material of the positive electrode is filled with the charge-transporting ions. Therefore, thereby, the content of the charge-transporting ions in the positive electrode can be adjusted to an appropriate amount.

[0045] Also, the adjustment process S3 can also be performed by fabricating a single cell by combining a negative electrode which is an electrode taken out by the electrode extraction S2 and a counter electrode (positive electrode) capable of filling charge-transporting ions, and discharging the single cell. By discharging the single cell, charge-transporting ions are released from the negative electrode active material of the negative electrode and the counter electrode is filled with the charge-transporting ions. Therefore, thereby, the content of the charge-transporting ions in the negative electrode can be adjusted to an appropriate amount.

[0046] (Press S4) In this step, the electrode taken out from the recovered non-aqueous electrolyte storage element is pressed in the thickness direction. Thereby, since the contact area between the particles of the active material in the electrode to be reused, between the active material and the base material, etc. is enlarged, the performance of the obtained new non-aqueous electrolyte storage element can be enhanced, etc. Pressing in the thickness direction of the electrode can be performed by a known method using a roll press or the like.

[0047] For example, when the recovered non-aqueous electrolyte storage element includes a wound electrode body, the electrode body is flattened and, if necessary, separated into a positive electrode, a negative electrode, and a separator, and then at least one of the positive and negative electrodes to be reused can be pressed in the thickness direction. In this case, after cutting at least one of the positive and negative electrodes constituting the electrode body into a predetermined shape, pressing may be performed. That is, pressing S4 may be performed after cutting S5. Further, pressing S4 may be performed, for example, before the adjustment process S3 performed by assembling single cells, or may be performed after such an adjustment process S3.

[0048] (Cutting S5) In this step, the removed electrodes are cut. For example, when the recovered non-aqueous electrolyte storage element includes a wound electrode body, it may be cut in the width direction so as to divide the strip-shaped electrodes into a plurality, and a new non-aqueous electrolyte storage element including a stacked electrode body may be assembled. Further, when taking out only one of the positive and negative electrodes, for example, from the recovered non-aqueous electrolyte storage element having a wound electrode body and combining it with another electrode to produce a wound electrode body, both end portions of the strip-shaped electrodes in the original electrode body may be fixed or the like and thus may not be in a suitable state for reuse. In such a case, it is preferable to cut both end portions of the strip-shaped electrodes and use them for producing a new electrode body. On the other hand, when reusing a stacked electrode body to produce a stacked electrode body, since it is possible to use the original electrodes for producing the stacked electrode body without cutting, the electrode reuse rate can be increased.

[0049] (Manufacture of electrode body S6) In this step, an electrode body having the electrodes taken out from the recovered non-aqueous electrolyte storage element and subjected to the adjustment process S3 is manufactured. The taken-out electrodes used for manufacturing the electrode body may be the cut electrodes that have undergone cutting S5.

[0050] In this process, for example, when the positive electrode is taken out as the electrode to be reused from the recovered non-aqueous electrolyte storage element, an electrode body can be produced by combining it with a new negative electrode. Also, when the negative electrode is taken out as the electrode to be reused from the recovered non-aqueous electrolyte storage element, an electrode body can be produced by combining it with a new positive electrode. When active materials composed of single-particle system particles are used for both the positive and negative electrodes of the recovered non-aqueous electrolyte storage element, both the positive and negative electrodes can be taken out, subjected to appropriate treatment, etc., and these positive and negative electrodes can be combined again to produce an electrode body. Both the positive and negative electrodes can be taken out and each can be combined with a new electrode to produce a new electrode body. The electrodes to be combined may be electrodes recycled by a method different from the method for manufacturing a non-aqueous electrolyte storage element according to an embodiment of the present invention.

[0051] The electrode body produced in this process may be a wound-type electrode body, a laminated-type electrode body, or an electrode body of other shapes. The production of the electrode body can be carried out by a conventionally known method except that at least one of the positive and negative electrodes uses an electrode taken out from the recovered non-aqueous electrolyte storage element. For example, an electrode body can be produced by laminating or winding the positive and negative electrodes via a separator.

[0052] (Assembly S7) In this process, a new non-aqueous electrolyte storage element including the electrode on which the adjustment process S3 has been performed and which was incorporated in the recovered non-aqueous electrolyte storage element is assembled. In this process, a new non-aqueous electrolyte storage element may be assembled using the electrode body obtained by the production S6 of the electrode body. This process can be carried out by a method similar to that of a conventional known non-aqueous electrolyte storage element except that at least one of the positive and negative electrodes uses an electrode on which the adjustment process S3 has been performed and which was incorporated in the recovered non-aqueous electrolyte storage element. For example, in the assembly S7, the electrode body and the non-aqueous electrolyte are accommodated in a container. When a non-aqueous electrolyte solution is used as the non-aqueous electrolyte, after injecting the non-aqueous electrolyte solution from the injection port formed in the container, the injection port is sealed, whereby a new non-aqueous electrolyte storage element is obtained.

[0053] (Other processes, etc.) The method for manufacturing a non-aqueous electrolyte storage element according to an embodiment of the present invention may further include other processes other than the above-described respective processes. For example, in the manufacturing method, cleaning, drying, etc. may be performed on the taken-out electrode, the electrode after the adjustment process, etc. Cleaning, drying, etc. may be performed multiple times at appropriate timings. Also, the adjustment process S3, the pressing S4, the cutting S5, etc. may also be performed in multiple steps at appropriate timings. On the other hand, each process may be performed once.

[0054] According to the method for manufacturing a non-aqueous electrolyte storage element according to an embodiment of the present invention, it is possible to obtain a new non-aqueous electrolyte storage element with sufficient performance by directly reusing the electrodes provided in the recovered non-aqueous electrolyte storage element. The structure, etc. of the new non-aqueous electrolyte storage element obtained by the manufacturing method are not particularly limited. Hereinafter, the specific forms of the recovered non-aqueous electrolyte storage element used for reuse and the specific forms of the obtained new non-aqueous electrolyte storage element will be collectively described. However, the recovered non-aqueous electrolyte storage element and the new non-aqueous electrolyte storage element may differ or be the same in terms of structure, shape, size, performance, use, etc.

[0055] (Recovered non-aqueous electrolyte storage element and new non-aqueous electrolyte storage element) The recovered non-aqueous electrolyte storage element and the new non-aqueous electrolyte storage element (hereinafter, simply referred to as "non-aqueous electrolyte storage element") include an electrode body having a positive electrode, a negative electrode, and a separator, a non-aqueous electrolyte, and a container that houses the electrode body and the non-aqueous electrolyte. The electrode body is usually a laminated type in which a plurality of positive electrodes and a plurality of negative electrodes are laminated via a separator, or a wound type in which a positive electrode and a negative electrode are wound in a state of being laminated via a separator. The non-aqueous electrolyte exists in a state of being impregnated in the positive electrode, the negative electrode, and the separator. As an example of the non-aqueous electrolyte storage element, a non-aqueous electrolyte secondary battery will be described.

[0056] (Positive electrode) The positive electrode has a positive electrode substrate and a positive electrode active material layer disposed directly or via an intermediate layer on the positive electrode substrate.

[0057] The positive electrode substrate has conductivity. Whether it has "conductivity" or not is determined by taking the volume resistivity measured in accordance with JIS-H-0505 (1975) as 10 -2 Ω·cm as the threshold value. As the material of the positive electrode substrate, metals such as aluminum, titanium, tantalum, and stainless steel, or alloys thereof are used. Among these, aluminum or an aluminum alloy is preferable from the viewpoints of potential resistance, high conductivity, and cost. Examples of the positive electrode substrate include foil, vapor deposition film, mesh, porous material, etc., and foil is preferable from the viewpoint of cost. Therefore, as the positive electrode substrate, aluminum foil or aluminum alloy foil is preferable. Examples of aluminum or an aluminum alloy include A1085, A3003, A1N30, etc. defined in JIS-H-4000 (2014) or JIS-H-4160 (2006).

[0058] The average thickness of the positive electrode substrate is preferably 3 μm or more and 50 μm or less, more preferably 5 μm or more and 40 μm or less, still more preferably 8 μm or more and 30 μm or less, and particularly preferably 10 μm or more and 25 μm or less. By setting the average thickness of the positive electrode substrate within the above range, the strength of the positive electrode substrate can be increased while increasing the energy density per unit volume of the non-aqueous electrolyte storage element.

[0059] The intermediate layer is a layer disposed between the positive electrode substrate and the positive electrode active material layer. The intermediate layer contains a conductive agent such as carbon particles to reduce the contact resistance between the positive electrode substrate and the positive electrode active material layer. The configuration of the intermediate layer is not particularly limited, and for example, it contains a binder and a conductive agent.

[0060] The positive electrode active material layer contains a positive electrode active material. The positive electrode active material layer contains optional components such as a conductive agent, a binder, a thickener, and a filler as required.

[0061] As the positive electrode active material, it can be appropriately selected from known positive electrode active materials. As the positive electrode active material for a lithium-ion secondary battery, a material that can usually occlude and release lithium ions is used. Examples of the positive electrode active material include, for example, α-NaFeO 2Examples of such compounds include transition metal composite oxides having a crystalline structure such as α-NaFeO, transition metal composite oxides having a spinel crystalline structure, polyanion compounds, chalcogen compounds, and sulfur. 2 The transition metal complex oxide with the α-type crystal structure is α-NaFeO 2 Examples of the transition metal composite oxides having a spinel type crystal structure include lithium transition metal composite oxides having a spinel type crystal structure. 2 As an example of a lithium transition metal composite oxide having a crystalline structure, Li[Li x Ni (1-x) ]O 2 (0≦x<0.5), Li[Li x Ni γ Co (1-x-γ) ]O 2 (0≦x<0.5, 0<γ<1, 0<1-x-γ), Li[Li x Co (1-x) ]O 2 (0≦x<0.5), Li[Li x Ni γ Mn (1-x-γ) ]O 2 (0≦x<0.5, 0<γ<1, 0<1-x-γ), Li[Li x Ni γ Mn β Co (1-x-γ-β) ]O 2 (0≦x<0.5, 0<γ, 0<β, 0.5<γ+β<1, 0<1-x-γ-β), Li[Li x Ni γ Co β Al (1-x-γ-β) ]O 2 (0≦x<0.5, 0<γ, 0<β, 0.5<γ+β<1, 0<1-x-γ-β). Lithium transition metal composite oxides with spinel crystal structure include Li x Mn 2 O 4 , Li x Ni γ Mn (2-γ) O 4 Examples of polyanion compounds include LiFePO 4 , LiMnPO 4, LiNiPO 4 , LiCoPO 4 , Li 3 V 2 (PO 4 ) 3 , Li 2 MnSiO 4 , Li 2 CoPO 4 F, etc. Examples of chalcogen compounds include titanium disulfide, molybdenum disulfide, molybdenum dioxide, etc. Atoms or polyanions in these materials may be partially substituted with atoms or anion species composed of other elements. The surfaces of these materials may be coated with other materials. One of these materials may be used alone, or two or more of them may be mixed and used.

[0062] As the positive electrode active material, it is preferably a lithium transition metal composite oxide containing a lithium element, and more preferably a lithium transition metal composite oxide having an α-NaFeO 2 -type crystal structure. Further, as the positive electrode active material, it is preferably to contain at least one of nickel element, cobalt element and manganese element, more preferably to contain nickel element, cobalt element and manganese element, and even more preferably a lithium nickel cobalt manganese composite oxide. One or two or more of the positive electrode active materials can be used.

[0063] Examples of the lithium transition metal composite oxide include, for example, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 , LiNi 3 / 5 Co 1 / 5 Mn 1 / 5 O 2 , LiNi 1 / 2 Co 1 / 5 Mn 3 / 10 O 2 , LiNi 1 / 2 Co 3 / 10 Mn 1 / 5 O 2 , LiNi 8 / 10 Co 1 / 10 Mn 1 / 10 O 2 , LiNi0.8 Co 0.15 Al 0.05 O 2 Examples include Co, Al, O, etc.

[0064] The positive electrode active material preferably contains a lithium transition metal composite oxide at a ratio of 50% by mass or more (preferably 70 to 100% by mass, more preferably 80 to 100% by mass) of the total positive electrode active material in the positive electrode active material layer, and it is more preferable to use a positive electrode active material consisting essentially of only the lithium transition metal composite oxide.

[0065] The positive electrode active material is usually in the form of particles (powder). In one embodiment of the present invention, the positive electrode active material of the positive electrode provided in the recovered non-aqueous electrolyte storage element and the new non-aqueous electrolyte storage element contains an active material composed of single-particle system particles. The average particle diameter of the positive electrode active material is preferably, for example, 0.1 μm or more and 20 μm or less. By setting the average particle diameter of the positive electrode active material to be equal to or greater than the above lower limit, the production or handling of the positive electrode active material becomes easy. By setting the average particle diameter of the positive electrode active material to be equal to or less than the above upper limit, the electron conductivity of the positive electrode active material layer is improved. When using a composite of the positive electrode active material and other materials, the average particle diameter of the composite is taken as the average particle diameter of the positive electrode active material.

[0066] To obtain powder with a predetermined particle size, a pulverizer, a classifier, etc. are used. Examples of the pulverization method include methods using a mortar, a ball mill, a sand mill, a vibration ball mill, a planetary ball mill, a jet mill, a counter jet mill, a swirling air flow type jet mill, or a sieve. During pulverization, wet pulverization with the coexistence of water or an organic solvent such as hexane can also be used. As the classification method, a sieve, an air classifier, etc. are used as needed for both dry and wet processes.

[0067] The content of the positive electrode active material in the positive electrode active material layer is preferably 50% by mass or more and 99% by mass or less, more preferably 70% by mass or more and 98% by mass or less, and still more preferably 80% by mass or more and 95% by mass or less. By setting the content of the positive electrode active material within the above range, it is possible to achieve both high energy density and manufacturability of the positive electrode active material layer. In one embodiment of the present invention, the content of the active material composed of single-particle system particles in the positive electrode active material layer may be 50% by mass or more and 99% by mass or less, may be 70% by mass or more and 98% by mass or less, or may be 80% by mass or more and 95% by mass or less.

[0068] The conductive agent is not particularly limited as long as it is a material having conductivity. Examples of such conductive agents include carbonaceous materials, metals, conductive ceramics, and the like. Examples of carbonaceous materials include graphite, non-graphite carbon, graphene-based carbon, and the like. Examples of non-graphite carbon include carbon nanofibers, pitch-based carbon fibers, carbon black, and the like. Examples of carbon black include furnace black, acetylene black, ketjen black, and the like. Examples of graphene-based carbon include graphene, carbon nanotube (CNT), fullerene, and the like. Examples of the shape of the conductive agent include powder form, fibrous form, and the like. As the conductive agent, one of these materials may be used alone, or two or more of them may be mixed and used. Further, these materials may be used in a composite form. For example, a material obtained by compositing carbon black and CNT may be used. Among these, carbon black is preferable from the viewpoints of electron conductivity and coatability, and among them, acetylene black is preferable.

[0069] The content of the conductive agent in the positive electrode active material layer is preferably 1% by mass or more and 10% by mass or less, and more preferably 3% by mass or more and 9% by mass or less. By setting the content of the conductive agent within the above range, the energy density of the non-aqueous electrolyte storage element can be increased.

[0070] Examples of the binder include thermoplastic resins such as fluororesins (polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), etc.), polyethylene, polypropylene, polyacrylic, and polyimide; elastomers such as ethylene-propylene-diene rubber (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), and fluororubber; and polysaccharide polymers.

[0071] The content of the binder in the positive electrode active material layer is preferably 1% by mass or more and 10% by mass or less, and more preferably 3% by mass or more and 9% by mass or less. By setting the content of the binder within the above range, the positive electrode active material can be stably held.

[0072] Examples of the thickener include polysaccharide polymers such as carboxymethyl cellulose (CMC) and methyl cellulose. When the thickener has a functional group that reacts with lithium or the like, this functional group may be deactivated in advance by methylation or the like. When using a thickener, the content of the thickener in the positive electrode active material layer is preferably 5% by mass or less, and more preferably 1% by mass or less. The positive electrode active material layer may not contain a thickener.

[0073] The filler is not particularly limited. Examples of the filler include polyolefins such as polypropylene and polyethylene, inorganic oxides such as silicon dioxide, alumina, titanium dioxide, calcium oxide, strontium oxide, barium oxide, and magnesium oxide, hydroxides such as magnesium hydroxide, calcium hydroxide, and aluminum hydroxide, carbonates such as calcium carbonate, sparingly soluble ionic crystals such as calcium fluoride, barium fluoride, and barium sulfate, nitrides such as aluminum nitride and silicon nitride, and mineral resource-derived substances such as talc, montmorillonite, boehmite, zeolite, apatite, kaolin, mullite, spinel, olivine, sericite, bentonite, and mica, or artificial products thereof. When using a filler, the content of the filler in the positive electrode active material layer is preferably 5% by mass or less, and more preferably 1% by mass or less. The positive electrode active material layer may not contain a filler.

[0074] The positive electrode active material layer may contain typical non-metal elements such as B, N, P, F, Cl, Br, I, etc., typical metal elements such as Li, Na, Mg, Al, K, Ca, Zn, Ga, Ge, Sn, Sr, Ba, etc., and transition metal elements such as Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Zr, Nb, W, etc. as components other than the positive electrode active material, conductive agent, binder, thickener, and filler.

[0075] (Negative electrode) The negative electrode has a negative electrode substrate and a negative electrode active material layer disposed directly or via an intermediate layer on the negative electrode substrate. The configuration of the intermediate layer is not particularly limited, and can be selected, for example, from the configurations exemplified for the positive electrode above.

[0076] The negative electrode substrate has conductivity. As the material of the negative electrode substrate, metals such as copper, nickel, stainless steel, nickel-plated steel, aluminum, or alloys thereof, carbonaceous materials, etc. are used. Among these, copper or a copper alloy is preferable. Examples of the negative electrode substrate include foil, vapor deposition film, mesh, porous material, etc., and foil is preferable from the viewpoint of cost. Therefore, a copper foil or a copper alloy foil is preferable as the negative electrode substrate. Examples of the copper foil include rolled copper foil, electrolytic copper foil, etc.

[0077] The average thickness of the negative electrode substrate is preferably 2 μm or more and 35 μm or less, more preferably 3 μm or more and 30 μm or less, still more preferably 4 μm or more and 25 μm or less, and particularly preferably 5 μm or more and 20 μm or less. By setting the average thickness of the negative electrode substrate within the above range, it is possible to increase the strength of the negative electrode substrate while increasing the energy density per volume of the non-aqueous electrolyte storage element.

[0078] The negative electrode active material layer contains a negative electrode active material. The negative electrode active material layer may contain optional components such as a conductive agent, binder, thickener, filler, etc. as required. Optional components such as a conductive agent, binder, thickener, filler, etc. can be selected from the materials exemplified for the positive electrode above.

[0079] The negative electrode active material layer may contain, as components other than the negative electrode active material, conductive agent, binder, thickener, and filler, typical non-metal elements such as B, N, P, F, Cl, Br, I, etc., typical metal elements such as Li, Na, Mg, Al, K, Ca, Zn, Ga, Ge, Sn, Sr, Ba, etc., and transition metal elements such as Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Zr, Ta, Hf, Nb, W, etc.

[0080] The negative electrode active material can be appropriately selected from known negative electrode active materials. As the negative electrode active material for a lithium-ion secondary battery, a material that can occlude and release lithium ions is usually used. Examples of the negative electrode active material include metallic lithium; metals or semi-metals such as Si and Sn; metal oxides or semi-metal oxides such as silicon oxide, titanium oxide, and tin oxide; Li 4 Ti 5 O 12 , LiTiO 2、 TiNb 2 O 7 and other titanium-containing oxides; polyphosphoric acid compounds; silicon carbide; carbon materials such as graphite (graphite) and non-graphitic carbon (easily graphitizable carbon or hardly graphitizable carbon). Among these materials, graphite and non-graphitic carbon are preferred. In the negative electrode active material layer, one of these materials may be used alone, or two or more of them may be mixed and used.

[0081] "Graphite" refers to a carbon material having an average lattice plane spacing (d 002 ) of the (002) plane determined by X-ray diffraction method of 0.33 nm or more and less than 0.34 nm before charge and discharge or in the discharged state. Examples of graphite include natural graphite and artificial graphite. From the viewpoint of obtaining a material with stable physical properties, artificial graphite is preferred.

[0082] "Non-graphitic carbon" refers to the average lattice plane spacing (d 002refers to a carbon material having a d-spacing of 0.34 nm or more and 0.42 nm or less. Examples of non-graphitic carbon include non-graphitizable carbon and graphitizable carbon. Examples of non-graphitic carbon include materials derived from resins, petroleum pitch or materials derived from petroleum pitch, petroleum coke or materials derived from petroleum coke, plant-derived materials, alcohol-derived materials, and the like.

[0083] Here, the "discharged state" means a state in which lithium ions that can be occluded and released during charge and discharge are sufficiently released from the carbon material that is the negative electrode active material. For example, in a half-cell using a negative electrode containing a carbon material as the working electrode and metallic Li as the counter electrode, it is a state in which the open circuit voltage is 0.7 V or more.

[0084] "Non-graphitizable carbon" refers to a carbon material having a d-spacing of 002 of 0.36 nm or more and 0.42 nm or less.

[0085] "Graphitizable carbon" refers to a carbon material having a d-spacing of 002 of 0.34 nm or more and less than 0.36 nm.

[0086] The negative electrode active material is usually in the form of particles (powder). In one embodiment of the present invention, the negative electrode active material of the recovered non-aqueous electrolyte storage element and the new non-aqueous electrolyte storage element includes an active material composed of single-particle system particles. The average particle diameter of the negative electrode active material can be, for example, 1 nm or more and 100 μm or less. When the negative electrode active material is a carbon material, a titanium-containing oxide, or a polyphosphoric acid compound, its average particle diameter may be 1 μm or more and 100 μm or less. When the negative electrode active material is Si, Sn, a Si oxide, or a Sn oxide, etc., its average particle diameter may be 1 nm or more and 1 μm or less. By setting the average particle diameter of the negative electrode active material to be equal to or greater than the above lower limit, the production or handling of the negative electrode active material becomes easier. By setting the average particle diameter of the negative electrode active material to be equal to or less than the above upper limit, the electron conductivity of the negative electrode active material layer is improved. In order to obtain powder with a predetermined particle size, a pulverizer, a classifier, or the like is used. The pulverization method and the classification method can be selected, for example, from the methods exemplified for the positive electrode above. When the negative electrode active material is a metal such as metallic lithium, the negative electrode active material layer may be in the form of a foil.

[0087] The content of the negative electrode active material in the negative electrode active material layer is preferably 60% by mass or more and 99% by mass or less, and more preferably 90% by mass or more and 98% by mass or less. By setting the content of the negative electrode active material within the above range, both high energy density and manufacturability of the negative electrode active material layer can be achieved. In one embodiment of the present invention, the content of the active material composed of single-particle system particles in the negative electrode active material layer may be 60% by mass or more and 99% by mass or less, or may be 90% by mass or more and 98% by mass or less.

[0088] (Separator) The separator can be appropriately selected from known separators. As the separator, for example, a separator composed only of a base material layer, a separator having a heat-resistant layer containing heat-resistant particles and a binder formed on one or both surfaces of the base material layer, etc. can be used. Examples of the shape of the base material layer of the separator include woven fabric, non-woven fabric, porous resin film, etc. Among these shapes, a porous resin film is preferable from the viewpoint of strength, and a non-woven fabric is preferable from the viewpoint of the liquid retention property of the non-aqueous electrolyte. As the material of the base material layer of the separator, polyolefins such as polyethylene and polypropylene are preferable from the viewpoint of the shutdown function, and polyimides, aramids, etc. are preferable from the viewpoint of oxidation decomposition resistance. As the base material layer of the separator, a material in which these resins are combined may be used.

[0089] The heat-resistant particles contained in the heat-resistant layer preferably have a mass reduction of 5% or less when the temperature is raised from room temperature to 500 °C in an air atmosphere at 1 atm, and more preferably have a mass reduction of 5% or less when the temperature is raised from room temperature to 800 °C. Examples of materials with a mass reduction of a predetermined value or less include inorganic compounds. Examples of inorganic compounds include oxides such as iron oxide, silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, calcium oxide, strontium oxide, barium oxide, magnesium oxide, and aluminosilicate; nitrides such as aluminum nitride and silicon nitride; carbonates such as calcium carbonate; sulfates such as barium sulfate; sparingly soluble ionic crystals such as calcium fluoride, barium fluoride, and barium titanate; covalent crystals such as silicon and diamond; mineral resource-derived substances such as talc, montmorillonite, boehmite, zeolite, apatite, kaolin, mullite, spinel, olivine, sericite, bentonite, mica, or artificial products thereof, etc. As the inorganic compound, these substances may be used alone or as a complex, or two or more of them may be mixed and used. Among these inorganic compounds, silicon oxide, aluminum oxide, or aluminosilicate is preferable from the viewpoint of the safety of the non-aqueous electrolyte storage element.

[0090] The porosity of the separator is preferably 80% by volume or less from the viewpoint of strength, and preferably 20% by volume or more from the viewpoint of discharge performance. Here, the "porosity" is a value based on volume and means the measured value by a mercury porosimeter.

[0091] As the separator, a polymer gel composed of a polymer and a non-aqueous electrolyte may be used. Examples of the polymer include polyacrylonitrile, polyethylene oxide, polypropylene oxide, polymethyl methacrylate, polyvinyl acetate, polyvinyl pyrrolidone, polyvinylidene fluoride, and the like. Using a polymer gel has the effect of suppressing liquid leakage. As the separator, a porous resin film or non-woven fabric as described above and a polymer gel may be used in combination.

[0092] (Non-aqueous electrolyte) The non-aqueous electrolyte can be appropriately selected from known non-aqueous electrolytes. As the non-aqueous electrolyte, a non-aqueous electrolyte solution may be used. The non-aqueous electrolyte solution contains a non-aqueous solvent and an electrolyte salt dissolved in this non-aqueous solvent.

[0093] The non-aqueous solvent can be appropriately selected from known non-aqueous solvents. Examples of the non-aqueous solvent include cyclic carbonates, chain carbonates, carboxylic acid esters, phosphate esters, sulfonic acid esters, ethers, amides, nitriles, and the like. As the non-aqueous solvent, those in which a part of the hydrogen atoms contained in these compounds are substituted with halogens may be used.

[0094] Examples of the cyclic carbonate include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), vinyl ethylene carbonate (VEC), chloroethylene carbonate, fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), styrene carbonate, 1-phenylvinylene carbonate, 1,2-diphenylvinylene carbonate, and the like. Among these, EC is preferred.

[0095] Examples of the chain carbonate include diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diphenyl carbonate, trifluoroethyl methyl carbonate, bis(trifluoroethyl) carbonate, and the like. Among these, EMC is preferred.

[0096] As the non-aqueous solvent, it is preferable to use a cyclic carbonate or a chain carbonate, and it is more preferable to use a cyclic carbonate and a chain carbonate in combination. By using a cyclic carbonate, dissociation of the electrolyte salt can be promoted and the ionic conductivity of the non-aqueous electrolyte can be improved. By using a chain carbonate, the viscosity of the non-aqueous electrolyte can be kept low. When using a cyclic carbonate and a chain carbonate in combination, the volume ratio of the cyclic carbonate to the chain carbonate (cyclic carbonate:chain carbonate) is preferably in the range of, for example, 5:95 to 50:50.

[0097] The electrolyte salt can be appropriately selected from known electrolyte salts. Examples of the electrolyte salt include lithium salts, sodium salts, potassium salts, magnesium salts, onium salts, and the like. Among these, lithium salts are preferred.

[0098] Examples of the lithium salt include inorganic lithium salts such as LiPF 6 , LiPO 2 F 2 , LiBF 4 , LiClO 4 , LiN(SO 2 F) 2 , lithium oxalate salts such as lithium bis(oxalate) borate (LiBOB), lithium difluorooxalate borate (LiFOB), lithium bis(oxalate) difluorophosphate (LiFOP), LiSO 3 CF 3 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2 、LiN(SO2 CF 3 )(SO 2 C 4 F 9 )、LiC(SO 2 CF 3 ) 3 、LiC(SO 2 C 2 F 5 ) 3 Examples of the lithium salt and the like having a halogenated hydrocarbon group such as these include lithium salts having a halogenated hydrocarbon group such as these. Among these, inorganic lithium salts are preferred, and LiPF 6 is more preferred.

[0099] The content of the electrolyte salt in the non-aqueous electrolyte is preferably 0.1 mol / dm 3 or more and 2.5 mol / dm 3 or less at 20 °C and 1 atm, more preferably 0.3 mol / dm 3 or more and 2.0 mol / dm 3 or less, even more preferably 0.5 mol / dm 3 or more and 1.7 mol / dm 3 or less, and particularly preferably 0.7 mol / dm 3 or more and 1.5 mol / dm 3 or less. By setting the content of the electrolyte salt within the above range, the ionic conductivity of the non-aqueous electrolyte can be increased.

[0100] The non-aqueous electrolyte may contain an additive in addition to the non-aqueous solvent and the electrolyte salt. Examples of the additive include aromatic compounds such as biphenyl, alkyl biphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, dibenzofuran; partial halides of the aromatic compounds such as 2-fluorobiphenyl, o-cyclohexylfluorobenzene, p-cyclohexylfluorobenzene; halogenated anisole compounds such as 2,4-difluoroanisole, 2,5-difluoroanisole, 2,6-difluoroanisole, 3,5-difluoroanisole; vinylene carbonate, methyl vinylene carbonate, ethyl vinylene carbonate, succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride; ethylene sulfite, propylene sulfite, dimethyl sulfite, methyl methanesulfonate, busulfan, methyl toluenesulfonate, dimethyl sulfate, ethylene sulfate, sulfolane, dimethyl sulfone, diethyl sulfone, dimethyl sulfoxide, diethyl sulfoxide, tetramethylene sulfoxide, diphenyl sulfide, 4,4'-bis(2,2-dioxo-1,3,2-dioxathiolane), 4-methylsulfonyloxymethyl-2,2-dioxo-1,3,2-dioxathiolane, thioanisole, diphenyl disulfide, dipyridinium disulfide, 1,3-propenesultone, 1,3-propanesultone, 1,4-butanesultone, 1,4-butenesultone, perfluorooctane, tris(trimethylsilyl) borate, tris(trimethylsilyl) phosphate, tetrakis(trimethylsilyl) titanate, lithium monofluorophosphate, lithium difluorophosphate, etc. These additives may be used alone or in combination of two or more kinds.

[0101] The content of the additive contained in the non-aqueous electrolyte is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 7% by mass or less, still more preferably 0.2% by mass or more and 5% by mass or less, and particularly preferably 0.3% by mass or more and 3% by mass or less with respect to the mass of the entire non-aqueous electrolyte. By setting the content of the additive within the above range, the capacity retention performance or cycle performance after high-temperature storage can be improved, or the safety can be further improved.

[0102] A solid electrolyte may be used for the non-aqueous electrolyte, or a non-aqueous electrolyte and a solid electrolyte may be used in combination.

[0103] As the solid electrolyte, any material having ion conductivity such as lithium, sodium, calcium, etc. and being solid at normal temperature (for example, from 15°C to 25°C) can be selected. Examples of the solid electrolyte include sulfide solid electrolytes, oxide solid electrolytes, nitride solid electrolytes, polymer solid electrolytes, and the like.

[0104] As the sulfide solid electrolyte, in the case of a lithium-ion secondary battery, for example, Li 2 S-P 2 S 5 、LiI-Li 2 S-P 2 S 5 、Li 10 Ge-P 2 S 12 and the like.

[0105] The shape of the non-aqueous electrolyte storage element is not particularly limited, and examples include cylindrical batteries, square batteries, flat batteries, coin-type batteries, button-type batteries, and the like.

[0106] FIG. 2 shows a non-aqueous electrolyte storage element 1 as an example of a square battery. Note that the figure is a perspective view of the inside of the container. An electrode body 2 having a positive electrode and a negative electrode wound with a separator interposed therebetween is housed in a square container 3. The positive electrode is electrically connected to a positive electrode terminal 4 via a positive electrode lead 41. The negative electrode is electrically connected to a negative electrode terminal 5 via a negative electrode lead 51.

[0107] Rechargeable device The non-aqueous electrolyte rechargeable element can be mounted as a rechargeable unit (battery module) formed by aggregating a plurality of non-aqueous electrolyte rechargeable elements in a power source for vehicles such as electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), a power source for electronic devices such as personal computers and communication terminals, or a power source for power storage, etc.

[0108] Fig. 3 shows an example of a rechargeable device 30 formed by further aggregating rechargeable units 20 in which two or more non-aqueous electrolyte rechargeable elements 1 electrically connected are aggregated. The rechargeable device 30 may include a bus bar (not shown) for electrically connecting two or more non-aqueous electrolyte rechargeable elements 1, a bus bar (not shown) for electrically connecting two or more rechargeable units 20, etc. The rechargeable unit 20 or the rechargeable device 30 may include a state monitoring device (not shown) for monitoring the state of one or more non-aqueous electrolyte rechargeable elements.

[0109] <Other embodiments> Note that the method for manufacturing the non-aqueous electrolyte rechargeable element of the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the gist of the present invention. For example, the configuration of another embodiment can be added to the configuration of a certain embodiment, and a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment or a well-known technique. Further, a part of the configuration of a certain embodiment can be deleted. Also, a well-known technique can be added to the configuration of a certain embodiment.

[0110] In the above-described embodiments, the case where the non-aqueous electrolyte rechargeable element is used as a non-aqueous electrolyte secondary battery (for example, a lithium-ion secondary battery) capable of charge and discharge has been described. However, the type, shape, dimensions, capacity, etc. of the non-aqueous electrolyte rechargeable element are arbitrary. The present invention can also be applied to various secondary batteries, electric double layer capacitors, or capacitors such as lithium-ion capacitors.

[0111] In the above-described embodiment, the electrode body in which the positive electrode and the negative electrode are laminated with a separator therebetween has been described. However, the electrode body may not include a separator. For example, the positive electrode and the negative electrode may be in direct contact with each other in a state where a layer having no conductivity is formed on the active material layer of the positive electrode or the negative electrode.

Industrial Applicability

[0112] The present invention is useful as a technique for recycling non-aqueous electrolyte storage elements.

Explanation of Reference Numerals

[0113] 1 Non-aqueous electrolyte storage element 2 Electrode body 3 Container 4 Positive electrode terminal 41 Positive electrode lead 5 Negative electrode terminal 51 Negative electrode lead 20 Power storage unit 30 Power storage device

Claims

1. Removing the electrode from a recovered non-aqueous electrolyte storage element including a base material and an electrode having an active material layer disposed on the base material, Performing an adjustment process for the charge transport ion content on the electrode before or after removing the electrode, and Assembling a new non-aqueous electrolyte storage element including the electrode on which the adjustment process has been performed Comprising, A method for manufacturing a non-aqueous electrolyte storage element, wherein the active material layer includes an active material composed of secondary particles having a ratio of average particle diameter to average primary particle diameter of 3 or less, or primary particles that are not substantially aggregated.

2. The method for manufacturing a non-aqueous electrolyte storage element according to claim 1, further comprising pressing the removed electrode in the thickness direction.

3. Cutting the removed electrode, and Producing an electrode body having the cut electrode The method for manufacturing a non-aqueous electrolyte storage element according to claim 1 or claim 2, comprising.

4. The electrode is a positive electrode, The adjustment process is at least one of discharging the recovered non-aqueous electrolyte storage element and producing a single cell by combining the removed electrode and a counter electrode capable of releasing the charge transport ions, and discharging the single cell. The method for manufacturing a non-aqueous electrolyte storage element according to claim 1 or claim 2.

5. The method for manufacturing a non-aqueous electrolyte storage element according to claim 1 or claim 2, comprising confirming that the recovered non-aqueous electrolyte storage element includes an active material composed of secondary particles having a ratio of average particle diameter to average primary particle diameter of 3 or less, or primary particles that are not substantially aggregated in the active material layer.

6. The method for manufacturing a non-aqueous electrolyte storage element according to claim 1 or claim 2, wherein the active material includes a lithium transition metal composite oxide.

7. The method for manufacturing a non-aqueous electrolyte storage element according to claim 1 or claim 2, wherein the active material includes a lithium nickel cobalt manganese composite oxide.

8. The method for manufacturing a non-aqueous electrolyte storage element according to claim 1 or claim 2, wherein the average primary particle diameter of the active material is 1 μm or more and 10 μm or less.

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