A system to support the reuse of lithium-ion secondary batteries

Abstract

This reuse support system performs an electrode degradation determination to determine whether a degree of degradation of a ceramic electrode extracted from a lithium ion secondary battery that includes said ceramic electrode satisfies a condition allowing the ceramic electrode to be regenerated, on the basis of one or a plurality of types of first data obtained by diagnosing the ceramic electrode.

Description

[Technical Field]

[0001] The present invention relates generally to recycling of lithium-ion secondary batteries. [Background technology]

[0002] As a method for reusing a lithium ion secondary battery (specifically, reusing the entire lithium ion secondary battery or its components), for example, the reusing method (method for reusing a negative electrode active material layer) disclosed in Patent Document 1 is known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-127417 Summary of the Invention [Problem to be solved by the invention]

[0004] The reuse of lithium-ion secondary batteries as described above can be broadly divided into recycling and reuse. Battery recycling involves recovering materials such as electrodes as active materials or alloys, but this is costly due to the complex process. On the other hand, battery reuse involves evaluating the performance of batteries and reusing them for different purposes depending on their degree of deterioration. For example, batteries with only a small degree of deterioration can be reused in electric vehicles (EVs) or forklifts, while batteries with a large degree of deterioration can be reused as backup power sources.

[0005] As such, recycling lithium-ion secondary batteries is complicated and costly, while reuse has limited applications. For this reason, the reuse of lithium-ion secondary batteries has not progressed much. In particular, conventional lithium-ion secondary batteries, which contain organic binders and conductive additives in the electrodes (typically lithium-ion secondary batteries with current collectors and powder-coated electrodes), have many degradation factors, making it difficult to remove used electrodes and reuse them as electrodes.

[0006] An object of the present invention is to support the reuse of lithium ion secondary batteries. [Means for solving the problem]

[0007] The present inventors have discovered that by replacing the electrolyte in a used lithium ion secondary battery in which at least one of the positive and negative electrodes is a ceramic electrode (specifically, for example, a used sintered-type lithium ion secondary battery having battery elements including a ceramic positive electrode layer, a ceramic separator, and a ceramic negative electrode layer), and cleaning and / or heat treating the battery elements, a lithium ion secondary battery with sufficiently restored performance can be reassembled using a simple procedure at low cost.

[0008] Therefore, lithium ion secondary batteries having ceramic electrodes are adopted as the lithium ion secondary batteries, and a reuse support system, which is a computer system that supports the reuse of such lithium ion secondary batteries, is constructed.

[0009] The reuse support system performs an electrode deterioration determination, which is a determination of whether the degree of deterioration of the removed ceramic electrode satisfies the conditions for regenerating the ceramic electrode, based on one or more types of first data diagnosed on the ceramic electrode removed from a lithium ion secondary battery having the ceramic electrode. [Effects of the Invention]

[0010] This can support the reuse of lithium-ion secondary batteries. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view of an example of a lithium ion secondary battery according to an embodiment of the present invention. [Figure 2] 1 is an SEM image showing an example of a cross section perpendicular to the layer surface of an oriented positive electrode layer. [Figure 3] 3 is an EBSD image of a cross section of the oriented positive electrode layer shown in FIG. 2. [Figure 4] 4 is a histogram showing the distribution of orientation angles of primary particles in the EBSD image of FIG. 3 on an area basis. [Figure 5] FIG. 1 is a diagram illustrating an example of a value chain according to a comparative example. [Figure 6] FIG. 1 is a diagram illustrating an example of a value chain according to an embodiment. [Figure 7] 1 is a configuration diagram of an entire reuse system including a reuse support system according to an embodiment. [Figure 8] FIG. 1 is a configuration diagram of a reuse support system. [Figure 9] 1 is a flowchart showing a flow of recycling a lithium ion secondary battery. [Figure 10] 10 is a flowchart showing details of step S907 in FIG. 9. [Figure 11] 10 is a flowchart showing details of step S908 in FIG. 9. DETAILED DESCRIPTION OF THE INVENTION

[0012] In the following description, an "interface apparatus" may refer to one or more interface devices. The one or more interface devices may be at least one of the following: One or more I / O (Input / Output) interface devices. The I / O (Input / Output) interface devices are interface devices to at least one of the I / O device and a remote display computer. The I / O interface device to the display computer may be a communications interface device. The at least one I / O device may be a user interface device, for example, either an input device such as a keyboard and a pointing device, or an output device such as a display device. One or more communication interface devices. The one or more communication interface devices may be one or more homogeneous communication interface devices (e.g., one or more NICs (Network Interface Cards)) or two or more heterogeneous communication interface devices (e.g., an NIC and an HBA (Host Bus Adapter)).

[0013] In the following description, "memory" refers to one or more memory devices, which are an example of one or more storage devices, and may typically be a primary storage device. At least one memory device in the memory may be a volatile memory device or a non-volatile memory device.

[0014] In the following description, a "persistent storage device" may refer to one or more persistent storage devices, which are an example of one or more storage devices. A persistent storage device may typically be a non-volatile storage device (e.g., an auxiliary storage device), and more specifically, may be, for example, a hard disk drive (HDD), a solid state drive (SSD), a non-volatile memory express (NVME) drive, or a storage class memory (SCM).

[0015] In the following description, the term "storage device" may refer to at least one of memory and persistent storage device.

[0016] Furthermore, in the following description, a "processor" may refer to one or more processor devices. The at least one processor device may typically be a microprocessor device such as a CPU (Central Processing Unit), but may also be another type of processor device such as a GPU (Graphics Processing Unit). The at least one processor device may be a single-core or multi-core. The at least one processor device may also be a processor core. The at least one processor device may also be a processor device in a broader sense, such as a circuit that is a collection of gate arrays written in a hardware description language that performs part or all of the processing (for example, an FPGA (Field-Programmable Gate Array), a CPLD (Complex Programmable Logic Device), or an ASIC (Application Specific Integrated Circuit)).

[0017] Furthermore, in the following description, functions may be described using the expression "yyy unit." However, the functions may be realized by one or more computer programs executed by a processor, by one or more hardware circuits (e.g., FPGAs or ASICs), or by a combination thereof. When a function is realized by a program executed by a processor, the specified processing is performed using a storage device and / or an interface device, etc., as appropriate, and therefore the function may be considered to be at least a part of the processor. Processing described using a function as the subject may be processing performed by a processor or a device having the processor. A program may be installed from a program source. The program source may be, for example, a computer from which the program is distributed or a computer-readable recording medium (e.g., a non-transitory recording medium). The description of each function is an example, and multiple functions may be combined into one function, or one function may be divided into multiple functions.

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0019] First, an example of a lithium ion secondary battery having ceramic electrodes and an example of a method for reusing the lithium ion secondary battery will be described.

[0020] <How to reuse lithium-ion secondary batteries>

[0021] A lithium ion secondary battery is a sintered-type battery (semi-solid battery) that includes battery elements including a ceramic positive electrode layer, a ceramic separator, and a ceramic negative electrode layer, together with an electrolyte. FIG. 1 schematically shows an example of such a sintered-type lithium ion secondary battery. Note that although the lithium ion secondary battery 10 shown in FIG. 1 is in the form of a coin battery, in the present invention, the lithium ion secondary battery having ceramic electrodes is not limited to this and may be in other forms, such as a button battery, a cylindrical battery, a prismatic battery, a pack battery, a car battery, or a sheet battery.

[0022] That is, in the method for recycling a lithium-ion secondary battery, first, a used lithium-ion secondary battery 10 is prepared, which includes a battery element 21 including a ceramic positive electrode layer 12, a ceramic separator 20, and a ceramic negative electrode layer 16, an electrolyte 22, and a battery container 24 that accommodates the battery element 21 and the electrolyte 22. Then, after removing the battery element 21 from the lithium-ion secondary battery 10, the electrolyte 22 in the lithium-ion secondary battery 10 is replaced with fresh electrolyte 22. Next, the battery element 21 is subjected to an electrode restoration treatment that includes washing and / or heat treatment. Finally, the battery element 21 that has been subjected to the electrode restoration treatment is returned to the battery container 24, and the lithium-ion secondary battery 10 is assembled. In this way, by replacing the electrolyte 22 and cleaning and / or heat treating the battery element 21 of a used sintered-type lithium ion secondary battery 10 having a battery element 21 including a ceramic positive electrode layer 12, a ceramic separator 20, and a ceramic negative electrode layer 16, the lithium ion secondary battery 10 with sufficiently restored performance can be reassembled using a simple procedure at low cost.

[0023] As mentioned above, recycling lithium-ion secondary batteries involves complex processes and high costs, while reuse has limited applications. For this reason, the current situation is that little progress has been made in reusing lithium-ion secondary batteries or their components. In particular, conventional lithium-ion secondary batteries, which contain organic binders and conductive additives in their electrodes, have many degradation factors, making it difficult to remove used electrodes and reuse them as electrodes. This problem is solved in the present embodiment. This is explained as follows.

[0024] First, various factors are considered to be the general deterioration factors of conventional lithium-ion secondary batteries. First, when the battery is manufactured or in the early stages of use, the water contained in the electrolyte and the electrolyte anion, PF 5- The reaction with PF 5 Reactions between HF and the solvent, between the electrolyte and the active material, and side reactions resulting in the formation of carbonate and fluorinated layers on the electrode surface and gas generation occur. Second, battery use leads to the degradation and depletion of the active material itself. Repeated charge-discharge cycles cause particle cracking due to particle swelling and shrinkage, structural degradation and destruction due to phase changes and distortion, dissolution of the positive electrode active material, and deposition of the dissolved material at the negative electrode, which leads to short-circuiting between the positive and negative electrodes and a decrease in lithium ions. Low-temperature / high-current operation leads to the formation of Li dendrites at the negative electrode, which leads to a decrease in lithium ions and a short-circuiting between the positive and negative electrodes, as well as interface degradation. Furthermore, corrosion of the current collector surface, peeling of the active material from the current collector, decreased electrode conductivity, changes and disproportionation of the conductive network within the active material layer, binder degradation, and separator clogging, all of which contribute to an increase in the cell's internal resistance. Furthermore, depending on the conditions of use, various factors can be cited as causes of capacity degradation, such as a decrease in the reaction amount of the active material due to overcharging or overdischarging, oxidation of the electrolyte, deterioration due to reduction reactions, deterioration of the reaction interface layer, and deterioration due to expansion and contraction of the electrodes during charging and discharging.

[0025] In contrast, the used lithium-ion secondary battery of this embodiment is a sintered-type battery (hereinafter referred to as a "semi-solid battery") that includes a battery element 21, including a ceramic positive electrode layer 12, a ceramic separator 20, and a ceramic negative electrode layer 16, together with an electrolyte solution 22. Compared to typical lithium-ion secondary batteries, the battery element 21 is robust due to its ceramic structure, and the battery can be reassembled by repeatedly replacing the electrolyte solution 22. Advantageously, the main degradation modes in such semi-solid batteries are two of the various degradation factors mentioned above: "reaction between the electrolyte and the active material" and "dissolution of the positive electrode active material." That is, because each layer of the battery element 21 in a semi-solid battery is made of ceramic (i.e., a sintered body), it does not contain components that cause degradation, such as organic binders (organic binders are eliminated by sintering). As a result, ceramic electrodes that do not contain binders, etc., experience less degradation (there is no binder-related degradation). Furthermore, because the positive electrode / separator / negative electrode layer structure is made of ceramic, it can be removed in its original form after use, allowing for easy handling. Furthermore, because this structure is made of ceramic alone (even if a metal foil is attached, it can be removed or peeled off), it can be cleaned, degreased, fired, and other heat treatments. While degradation due to oxidative decomposition of the electrolyte 22 occurs, because the ceramic electrodes themselves are less susceptible to degradation, simply replacing the electrolyte 22 can restore the battery's performance to a certain extent. Therefore, according to the method of this embodiment, a lithium-ion secondary battery with fully restored performance can be reassembled using a used lithium-ion secondary battery in a simple procedure at low cost.

[0026] (1) Prepare used lithium-ion secondary batteries

[0027] A used lithium-ion secondary battery 10 is prepared. This lithium-ion secondary battery 10 is a sintered-body type battery (semi-solid battery) including a battery element 21 including a ceramic positive electrode layer 12, a ceramic separator 20, and a ceramic negative electrode layer 16, an electrolyte 22, and a battery container that accommodates the battery element 21 and the electrolyte 22. In particular, the ceramic positive electrode layer 12, the ceramic separator 20, and the ceramic negative electrode layer 16 form a single integrated sintered body as a whole, which is preferable from the perspective of improving work efficiency because it eliminates the need to handle the ceramic positive electrode layer 12, the ceramic negative electrode layer 16, and the separator 20 separately and allows handling as an integrated sintered body. The battery element may further include a positive electrode current collector 14 and / or a negative electrode current collector 18.

[0028] (2) Removal of the battery element

[0029] The battery element 21 is removed from the lithium-ion secondary battery 10 (specifically, the battery container 24). Removal of the battery element 21 can be performed by removing a part of the battery container 24 (for example, the negative electrode can 24b) to open the inside of the battery and removing the battery element 21, and this can be done as appropriate depending on the configuration of the battery container 24. In particular, when the ceramic positive electrode layer 12, the ceramic separator 20, and the ceramic negative electrode layer 16 form a single integrated sintered body as a whole, the integrated sintered body can be removed from the battery container 24 as a whole, which is particularly advantageous in terms of ease of operation.

[0030] (3) Replacing the electrolyte

[0031] The electrolyte 22 in the lithium ion secondary battery 10 (specifically, in the battery container 24) is replaced with fresh electrolyte 22. The replacement of the electrolyte 22 is preferably performed after the battery element 21 is removed, but is not limited to this. For example, when the battery container 24 is replaced, fresh electrolyte 22 may be placed in the replaced battery container 24. The fresh electrolyte 22 may have the same composition as the electrolyte 22 originally used in the lithium ion secondary battery 10, or may have a different composition from the electrolyte 22 originally used, as long as acceptable performance can be achieved. For example, an electrolyte 22 that provides better performance than the electrolyte 22 originally used may be used. Details of the preferred electrolyte 22 will be described later.

[0032] (4) Electrode restoration treatment

[0033] The battery element 21 is subjected to an electrode restoration treatment including washing and / or heat treatment. The method of the electrode restoration treatment is not particularly limited as long as the washing and / or heat treatment can improve the deteriorated electrode performance. Typically, the electrode restoration treatment is performed by washing the battery element 21 with a polar solvent to remove impurities contained in and / or attached to the battery element 21, and then drying. The polar solvent may be either a non-aqueous solvent or water. Examples of non-aqueous solvents include NMP (N-methyl-2-pyrrolidone), ethanol, etc. The method of cleaning with a polar solvent is not particularly limited, but it is preferably performed by immersing the battery element 21 in the polar solvent and performing ultrasonic cleaning or agitation.

[0034] The washed and dried battery element 21 is preferably heated at 300 to 1000°C, which further enhances electrode performance. Because the battery element 21 is a ceramic element (excluding the positive electrode current collector 14 and / or the negative electrode current collector 18), it can be subjected to heat treatments such as degreasing and firing (which cannot be performed on coated electrodes containing active materials and binders). In this case, the battery element 21 is preferably degreased and / or fired, and more preferably both degreasing and firing are performed. The battery element 21 can be degreased by heating the battery element at a temperature of preferably 300 to 600°C, more preferably 400 to 600°C, and the preferred holding time within this temperature range is 0.5 to 20 hours, more preferably 2 to 20 hours. This eliminates or burns off unnecessary components or impurities (such as the SEI) remaining in the battery element 21, further reducing their remaining amount and further improving battery performance. The battery element 21 may be fired by heating the battery element preferably at 650 to 1000°C, more preferably at 700 to 950°C, and the holding time within the above temperature range is preferably 0.01 to 20 hours, more preferably 0.01 to 15 hours. This restores or improves the crystallinity of the material, further enhancing battery performance. Further, by further sintering the electrode active material, the strength of the electrode active material layer can be improved. Furthermore, by using a lithium compound and / or a lithium-containing atmosphere during heat treatments such as degreasing and firing, the lithium content in the electrode active material can be optimized, thereby facilitating the recovery of performance of the positive electrode layer 12 and / or the negative electrode layer 16.

[0035] If the battery element 21 further includes a positive electrode current collector 14 and / or a negative electrode current collector 18, it is preferable to remove the positive electrode current collector 14 and / or the negative electrode current collector 18 before and / or during cleaning, and then attach the positive electrode current collector 14 and / or the negative electrode current collector 18 to the battery element 21 after the electrode restoration treatment. This allows the ceramic alone to be subjected to the cleaning and heat treatment described above. The positive electrode current collector 14 and / or the negative electrode current collector 18 attached to the battery element 21 after the electrode restoration treatment are not limited to new positive electrode current collector 14 and / or negative electrode current collector 18, and the removed positive electrode current collector 14 and / or negative electrode current collector 18 may be reused.

[0036] (5) Battery assembly

[0037] The battery element 21 that has been subjected to the electrode restoration treatment is returned to the battery container 24, and the lithium-ion secondary battery 10 is assembled. At this time, at least some of the parts that make up the battery container 24 may be replaced with new parts. Alternatively, the battery container 24 may be replaced with another battery container 24 after the battery element 21 is removed and before it is returned to the battery container 24.

[0038] <Lithium-ion secondary battery>

[0039] As shown in FIG. 1, a lithium-ion secondary battery 10 includes a ceramic positive electrode layer 12 (hereinafter referred to as the positive electrode layer 12), a ceramic negative electrode layer 16 (hereinafter referred to as the negative electrode layer 16), a ceramic separator 20 (hereinafter referred to as the separator 20), an electrolyte 22, and a battery container 24. The positive electrode layer 12 is made of a ceramic such as a lithium composite oxide sintered body. The negative electrode layer 16 is made of a ceramic such as a titanium-containing sintered body. The separator 20 is interposed between the positive electrode layer 12 and the negative electrode layer 16. The electrolyte 22 is impregnated into the positive electrode layer 12, the negative electrode layer 16, and the separator 20. The battery container 24 includes a sealed space in which the positive electrode layer 12, the negative electrode layer 16, the separator 20, and the electrolyte 22 are accommodated.

[0040] The positive electrode layer 12 is made of a lithium composite oxide sintered body. The fact that the positive electrode layer 12 is made of a sintered body means that the positive electrode layer 12 does not contain a binder or conductive additive. This is because even if the green sheet contains a binder, the binder will disappear or be burned away during firing. The absence of a binder in the positive electrode layer 12 has the advantage of preventing deterioration of the positive electrode due to the electrolyte solution 22. Note that it is particularly preferable that the lithium composite oxide constituting the sintered body is lithium cobalt oxide (typically LiCoO2 (hereinafter sometimes abbreviated as LCO)). Various lithium composite oxide sintered body plates or LCO sintered body plates are known.

[0041] According to a preferred embodiment, the positive electrode layer 12, i.e., the lithium composite oxide sintered body plate, is an oriented positive electrode layer containing a plurality of primary particles composed of a lithium composite oxide, the plurality of primary particles being oriented at an average orientation angle of more than 0° and not more than 30° relative to the layer surface of the positive electrode layer. Because the oriented positive electrode layer is oriented as described above, it is less susceptible to structural damage due to expansion and contraction during charge and discharge, making it particularly suitable for reuse. Figure 2 shows an example of a cross-sectional SEM image perpendicular to the layer surface of the oriented positive electrode layer 12, while Figure 3 shows an electron backscatter diffraction (EBSD) image of the cross-section perpendicular to the layer surface of the oriented positive electrode layer 12. Figure 4 also shows a histogram showing the area-based distribution of the orientation angles of the primary particles 11 in the EBSD image of Figure 3. The EBSD image shown in Figure 3 allows for observation of discontinuities in the crystal orientation. In Figure 3, the orientation angle of each primary particle 11 is indicated by different shades of color, with darker colors indicating smaller orientation angles. The orientation angle is the inclination angle of the (003) plane of each primary particle 11 relative to the layer surface direction. In Figures 2 and 3, the black areas inside the oriented positive electrode layer 12 are pores.

[0042] The aligned positive electrode layer 12 is an aligned sintered body composed of a plurality of primary particles 11 bonded to each other. Each primary particle 11 is mainly plate-shaped, but may include those formed in the shape of a rectangular parallelepiped, a cube, a sphere, etc. The cross-sectional shape of each primary particle 11 is not particularly limited, and may be rectangular, a polygon other than a rectangle, circular, elliptical, or a complex shape other than these.

[0043] Each primary particle 11 is composed of a lithium composite oxide. The lithium composite oxide is Li x MO2 (where 0.05 < x < 1.10, M is at least one type of transition metal, and M typically includes one or more of Co, Ni, and Mn), and is an oxide represented by this formula. The lithium composite oxide has a layered rock salt structure. The layered rock salt structure refers to a crystal structure in which lithium layers and transition metal layers other than lithium are alternately laminated with an oxygen layer sandwiched therebetween, that is, a crystal structure in which a transition metal ion layer and a lithium single layer are alternately laminated via oxide ions (typically an α-NaFeO2 type structure, that is, a structure in which transition metals and lithium are regularly arranged in the

[0111] axis direction of a cubic rock salt type structure). Examples of the lithium composite oxide include Li x CoO2 (lithium cobaltate), Li x NiO2 (lithium nickelate), Li x MnO2 (lithium manganate), Li x NiMnO2 (lithium nickel manganate), Li x NiCoO2 (lithium nickel cobaltate), Li x CoNiMnO2 (lithium cobalt nickel manganate), Li x CoMnO2 (lithium cobalt manganate), etc. are mentioned, and particularly preferably Li x CoO2 (lithium cobaltate, typically LiCoO2). The lithium composite oxide may contain one or more elements selected from Mg, Al, Si, Ca, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, Sr, Y, Zr, Nb, Mo, Ag, Sn, Sb, Te, Ba, Bi, and W.

[0044] As shown in Figures 3 and 4, the average value of the orientation angles of the primary particles 11, i.e., the average orientation angle, is greater than 0° and less than or equal to 30°. This brings about the following various advantages. First, because the primary particles 11 lie in a state inclined relative to the thickness direction, the adhesion between the primary particles can be improved. As a result, the lithium ion conductivity between a given primary particle 11 and other primary particles 11 adjacent to the given primary particle 11 on both sides of the given primary particle 11 in the longitudinal direction can be improved, thereby improving the rate characteristics. Second, the rate characteristics can be further improved. This is because, as described above, when lithium ions enter and exit the oriented positive electrode layer 12, expansion and contraction in the thickness direction predominates over expansion and contraction in the layer plane direction. This smooths the expansion and contraction of the oriented positive electrode layer 12, which in turn smooths the entry and exit of lithium ions. Third, since the expansion and contraction of the oriented positive electrode layer 12 due to the inflow and outflow of lithium ions occurs predominantly in the direction perpendicular to the layer surface, stress is less likely to occur at the bonding interface between the oriented positive electrode layer 12 and the separator 20, making it easier to maintain good bonding at the interface.

[0045] The average orientation angle of the primary particles 11 is obtained by the following method. First, in an EBSD image of a 95 μm × 125 μm rectangular region observed at 1000x magnification, as shown in FIG. 3 , three horizontal lines are drawn to divide the oriented positive electrode layer 12 into four equal parts in the thickness direction, and three vertical lines are drawn to divide the oriented positive electrode layer 12 into four equal parts in the layer surface direction. Next, the average orientation angle of the primary particles 11 is obtained by arithmetically averaging the orientation angles of all the primary particles 11 that intersect with at least one of the three horizontal and three vertical lines. From the viewpoint of further improving the rate characteristics, the average orientation angle of the primary particles 11 is preferably 30° or less, more preferably 25° or less. From the viewpoint of further improving the rate characteristics, the average orientation angle of the primary particles 11 is preferably 2° or more, more preferably 5° or more.

[0046] As shown in FIG. 4 , the orientation angles of the primary particles 11 may be distributed widely from 0° to 90°, but preferably the majority of the primary particles 11 are distributed in the range of more than 0° and less than or equal to 30°. That is, when the cross section of the oriented sintered body constituting the oriented positive electrode layer 12 is analyzed by EBSD, the total area of ​​the primary particles 11 contained in the analyzed cross section, which have an orientation angle of more than 0° and less than or equal to 30° relative to the layer surface of the oriented positive electrode layer 12 (hereinafter referred to as low-angle primary particles), is preferably 70% or more, more preferably 80% or more, of the total area of ​​the primary particles 11 contained in the cross section (specifically, the 30 primary particles 11 used to calculate the average orientation angle). This increases the proportion of primary particles 11 with high mutual adhesion, thereby further improving the rate characteristics. Furthermore, the total area of ​​the low-angle primary particles with an orientation angle of less than or equal to 20° is more preferably 50% or more of the total area of ​​the 30 primary particles 11 used to calculate the average orientation angle. Furthermore, the total area of ​​the low-angle primary particles having an orientation angle of 10° or less is more preferably 15% or more of the total area of ​​the 30 primary particles 11 used to calculate the average orientation angle.

[0047] Since each primary particle 11 is mainly plate-shaped, as shown in Figures 2 and 3, the cross section of each primary particle 11 extends in a predetermined direction and is typically approximately rectangular. That is, when the cross section of an oriented sintered body is analyzed by EBSD, the total area of ​​the primary particles 11 contained in the analyzed cross section, which have an aspect ratio of 4 or more, is preferably 70% or more, more preferably 80% or more, of the total area of ​​the primary particles 11 contained in the cross section (specifically, the 30 primary particles 11 used to calculate the average orientation angle). Specifically, in an EBSD image such as that shown in Figure 3, this can further improve the mutual adhesion between the primary particles 11, thereby further improving the rate characteristics. The aspect ratio of the primary particles 11 is the value obtained by dividing the maximum Feret diameter of the primary particles 11 by the minimum Feret diameter. The maximum Feret diameter is the maximum distance between two parallel lines when the primary particles 11 are sandwiched between the lines on the EBSD image when the cross section is observed. The minimum Feret diameter is the minimum distance between two parallel lines when the primary particle 11 is sandwiched between the lines on the EBSD image.

[0048] The average particle size of the multiple primary particles constituting the oriented sintered body is preferably 5 μm or more. Specifically, the average particle size of the 30 primary particles 11 used to calculate the average orientation angle is preferably 5 μm or more, more preferably 7 μm or more, and even more preferably 12 μm or more. This reduces the number of grain boundaries between the primary particles 11 in the direction of lithium ion conduction, improving overall lithium ion conductivity and further improving rate characteristics. The average particle size of the primary particles 11 is the arithmetic average of the circle-equivalent diameters of each primary particle 11. The circle-equivalent diameter is the diameter of a circle having the same area as each primary particle 11 on an EBSD image.

[0049] The positive electrode layer 12 preferably contains pores. When the sintered body contains pores, particularly open pores, the electrolyte can penetrate into the sintered body when the sintered body is incorporated into a battery as a positive electrode plate, thereby improving lithium ion conductivity. This is because, of the two types of lithium ion conduction within the sintered body, conduction via the constituent particles of the sintered body and conduction via the electrolyte in the pores, conduction via the electrolyte in the pores is overwhelmingly faster.

[0050] The positive electrode layer 12, i.e., the lithium composite oxide sintered body, preferably has a porosity of 20 to 60%, more preferably 25 to 55%, even more preferably 30 to 50%, and particularly preferably 30 to 45%. The pores are expected to provide a stress relief effect and increase capacity, and the mutual adhesion between the primary particles 11 can be further improved, resulting in improved rate characteristics. The porosity of the sintered body is calculated by polishing the cross section of the positive electrode layer with a cross-section polisher (CP), observing it with an SEM at 1000x magnification, and binarizing the resulting SEM image. The average equivalent circle diameter of each pore formed inside the oriented sintered body is not particularly limited, but is preferably 8 μm or less. The smaller the average equivalent circle diameter of each pore, the more the mutual adhesion between the primary particles 11 can be improved, resulting in further improved rate characteristics. The average equivalent circle diameter of the pores is the arithmetic average of the equivalent circle diameters of 10 pores in an EBSD image. The circle-equivalent diameter is the diameter of a circle having the same area as each pore on an EBSD image. Each pore formed inside the oriented sintered body is preferably an open pore that communicates with the outside of the positive electrode layer 12.

[0051] The average pore size of the positive electrode layer 12, i.e., the lithium composite oxide sintered body, is preferably 0.1 to 10.0 μm, more preferably 0.2 to 5.0 μm, and even more preferably 0.25 to 3.0 μm. Within the above range, localized stress concentration in large pores is suppressed, and stress within the sintered body is more likely to be released uniformly.

[0052] The thickness of the positive electrode layer 12 is preferably 60 to 450 μm, more preferably 70 to 350 μm, and even more preferably 90 to 300 μm. Within such a range, the active material capacity per unit area is increased, improving the energy density of the lithium-ion secondary battery 10, and deterioration of the battery characteristics (particularly an increase in resistance value) due to repeated charge and discharge can be suppressed.

[0053] The negative electrode layer 16 is made of a titanium-containing sintered body. The titanium-containing sintered body is lithium titanate Li4Ti5O 12 It is preferable that the battery contains Li4Ti5O (hereinafter referred to as LTO) or niobium titanium composite oxide Nb2TiO7, and more preferably contains LTO. Although LTO is known to typically have a spinel structure, it can also adopt other structures during charge and discharge. For example, LTO can be 12 (spinel structure) and Li7Ti5O 12 The reaction proceeds in the coexistence of two phases, i.e., spinel and rock salt structures. Therefore, LTO is not limited to a spinel structure.

[0054] The fact that the negative electrode layer 16 is made of a sintered body means that the negative electrode layer 16 does not contain a binder or conductive additive. This is because even if the green sheet contains a binder, the binder will disappear or be burned away during firing. Because the negative electrode layer does not contain a binder, the packing density of the negative electrode active material (e.g., LTO or Nb2TiO7) is high, resulting in high capacity and good charge / discharge efficiency.

[0055] The negative electrode layer 16, i.e., the titanium-containing sintered body, has a structure in which a plurality (i.e., a large number) of primary particles are bonded together. Therefore, it is preferable that these primary particles are made of LTO or Nb2TiO7.

[0056] The thickness of the negative electrode layer 16 is preferably 70 to 500 μm, more preferably 85 to 400 μm, and even more preferably 95 to 350 μm. The thicker the negative electrode layer 16, the easier it is to realize a battery with a high capacity and high energy density. The thickness of the negative electrode layer 16 can be obtained, for example, by measuring the distance between layer surfaces observed as approximately parallel when a cross section of the negative electrode layer 16 is observed with an SEM (scanning electron microscope).

[0057] The primary particle size, which is the average particle size of the multiple primary particles that make up the negative electrode layer 16, is preferably 1.2 μm or less, more preferably 0.02 to 1.2 μm, and even more preferably 0.05 to 0.7 μm. Within this range, it is easy to achieve both lithium ion conductivity and electronic conductivity, which contributes to improving rate performance.

[0058] The negative electrode layer 16 preferably contains pores. When the sintered body contains pores, particularly open pores, and is incorporated into a battery as a negative electrode layer, the electrolyte can penetrate into the sintered body, thereby improving lithium ion conductivity. This is because, of the two types of lithium ion conduction within the sintered body, conduction via the constituent particles of the sintered body and conduction via the electrolyte in the pores, conduction via the electrolyte in the pores is overwhelmingly faster.

[0059] The porosity of the negative electrode layer 16 is preferably 20 to 60%, more preferably 30 to 55%, and even more preferably 35 to 50%. Within such ranges, it is easy to achieve both lithium ion conductivity and electronic conductivity, which contributes to improving rate performance.

[0060] The average pore size of the negative electrode layer 16 is 0.08 to 5.0 μm, preferably 0.1 to 3.0 μm, and more preferably 0.12 to 1.5 μm. Within this range, it is easy to achieve both lithium ion conductivity and electronic conductivity, which contributes to improving rate performance.

[0061] The separator 20 is a microporous ceramic film. The separator 20 not only has excellent heat resistance, but also has the advantage of being able to be manufactured together with the positive electrode layer 12 and the negative electrode layer 16 as a single integrated sintered plate. The ceramic contained in the separator 20 is preferably at least one selected from MgO, Al2O3, ZrO2, SiC, Si3N4, AlN, and cordierite, and more preferably at least one selected from MgO, Al2O3, and ZrO2. The thickness of the separator 20 is preferably 3 to 40 μm, more preferably 5 to 35 μm, and even more preferably 10 to 30 μm. The porosity of the separator 20 is preferably 30 to 85%, and more preferably 40 to 80%.

[0062] The separator 20 may contain a glass component from the viewpoint of improving adhesion between the positive electrode layer 12 and the negative electrode layer 16. In this case, the content of the glass component in the separator 20 is preferably 0.1 to 50 wt %, more preferably 0.5 to 40 wt %, and even more preferably 0.5 to 30 wt %, based on the total weight of the separator 20. The glass component is preferably added to the separator 20 by adding glass frit to the raw material powder of the ceramic separator. However, as long as the desired adhesion between the separator 20 and the positive electrode layer 12 and the negative electrode layer 16 can be ensured, the separator 20 does not particularly need to contain a glass component.

[0063] The positive electrode layer 12, the separator 20, and the negative electrode layer 16 preferably form a single integrated sintered body plate as a whole, thereby bonding the positive electrode layer 12, the separator 20, and the negative electrode layer 16 to one another. That is, the three layers of the positive electrode layer 12, the separator 20, and the negative electrode layer 16 are preferably bonded to one another without relying on other bonding methods such as adhesives. Here, "forming a single integrated sintered body plate as a whole" means that a three-layer green sheet consisting of a positive electrode green sheet that provides the positive electrode layer 12, a separator green sheet that provides the separator 20, and a negative electrode green sheet that provides the negative electrode layer 16 is fired and each layer is sintered. Therefore, if the three-layer green sheet before firing is punched into a predetermined shape (e.g., a coin shape or a chip shape) using a punching die, there will be no misalignment between the positive electrode layer 12 and the negative electrode layer 16 in the final integrated sintered body plate. That is, the end faces of the positive electrode layer 12 and the negative electrode layer 16 are aligned, maximizing capacity. Alternatively, even if misalignment does exist, the integrated sintered body plate is suitable for processing, such as laser processing, cutting, and polishing, and the end faces can be finished to minimize or eliminate such misalignment. In any case, since the integrated sintered body plate is made of the positive electrode layer 12, separator 20, and negative electrode layer 16, the positive electrode layer 12 and the negative electrode layer 16 are bonded to each other, so misalignment between the positive electrode layer 12 and the negative electrode layer 16 does not occur later. By minimizing or eliminating the misalignment between the positive electrode layer 12 and the negative electrode layer 16 in this way, a high discharge capacity (i.e., close to the theoretical capacity) can be obtained as expected. Furthermore, because the integrated sintered body plate is a three-layer structure including a ceramic separator, it is less likely to undulate or warp (i.e., has excellent flatness) compared to a single positive electrode plate or a single negative electrode plate fabricated as a single sintered body plate. Therefore, the distance between the positive and negative electrodes is less likely to vary (i.e., is more uniform), which is thought to contribute to improved charge / discharge cycle performance.

[0064] The electrolyte solution 22 is not particularly limited, and a commercially available electrolyte solution for lithium batteries may be used, such as a solution in which a lithium salt (e.g., LiPF6) is dissolved in a non-aqueous solvent such as an organic solvent (e.g., a mixed solvent of ethylene carbonate (EC) and methyl ethyl carbonate (MEC), a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC), or a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC)).

[0065] To produce a lithium ion secondary battery with excellent heat resistance, the electrolyte solution 22 preferably contains lithium fluoroborate (LiBF4) in a non-aqueous solvent. In this case, the preferred non-aqueous solvent is at least one selected from the group consisting of γ-butyrolactone (GBL), ethylene carbonate (EC), and propylene carbonate (PC), more preferably a mixed solvent of EC and GBL, a single solvent of PC, a mixed solvent of PC and GBL, or a single solvent of GBL, and particularly preferably a mixed solvent of EC and GBL or a single solvent of GBL. By including γ-butyrolactone (GBL), the boiling point of the non-aqueous solvent increases, resulting in a significant improvement in heat resistance. From this perspective, the volume ratio of EC to GBL in the nonaqueous solvent containing EC and / or GBL is preferably 0:1 to 1:1 (GBL ratio of 50 to 100 volume%), more preferably 0:1 to 1:1.5 (GBL ratio of 60 to 100 volume%), even more preferably 0:1 to 1:2 (GBL ratio of 66.6 to 100 volume%), and particularly preferably 0:1 to 1:3 (GBL ratio of 75 to 100 volume%). Lithium borofluoride (LiBF4) dissolved in the nonaqueous solvent is an electrolyte with a high decomposition temperature, which also significantly improves heat resistance. The concentration of LiBF4 in the electrolytic solution 22 is preferably 0.5 to 2 mol / L, more preferably 0.6 to 1.9 mol / L, even more preferably 0.7 to 1.7 mol / L, and particularly preferably 0.8 to 1.5 mol / L.

[0066] The electrolyte solution 22 may further contain vinylene carbonate (VC) and / or fluoroethylene carbonate (FEC) and / or vinylethylene carbonate (VEC) as additives. Both VC and FEC have excellent heat resistance. Therefore, by including such additives in the electrolyte solution 22, an SEI film with excellent heat resistance can be formed on the surface of the negative electrode layer 16.

[0067] The battery container 24 has a sealed space, and the positive electrode layer 12, the negative electrode layer 16, the separator 20, and the electrolyte 22 are accommodated in this sealed space. The battery container 24 may be appropriately selected depending on the type of lithium-ion secondary battery 10. For example, when the lithium-ion secondary battery is in the form of a coin-type battery as shown in FIG. 1, the battery container 24 typically includes a positive electrode can 24a, a negative electrode can 24b, and a gasket 24c, and the positive electrode can 24a and the negative electrode can 24b are crimped together via the gasket 24c to form a sealed space. The positive electrode can 24a and the negative electrode can 24b may be made of a metal such as stainless steel, but are not particularly limited thereto. The gasket 24c may be a ring-shaped member made of an insulating resin such as polypropylene, polytetrafluoroethylene, or PFA resin, but are not particularly limited thereto.

[0068] The lithium-ion secondary battery 10 preferably further includes a positive electrode current collector 14 and / or a negative electrode current collector 18. The positive electrode current collector 14 and the negative electrode current collector 18 are not particularly limited, but are preferably metal foils such as copper foil or aluminum foil. The positive electrode current collector 14 is preferably disposed between the positive electrode layer 12 and the battery container 24 (e.g., the positive electrode can 24a), and the negative electrode current collector 18 is preferably disposed between the negative electrode layer 16 and the battery container 24 (e.g., the negative electrode can 24b). A positive electrode-side carbon layer 13 is preferably provided between the positive electrode layer 12 and the positive electrode current collector 14 to reduce contact resistance. Similarly, a negative electrode-side carbon layer 17 is preferably provided between the negative electrode layer 16 and the negative electrode current collector 18 to reduce contact resistance. Both the positive electrode-side carbon layer 13 and the negative electrode-side carbon layer 17 are preferably made of conductive carbon, and may be formed, for example, by applying a conductive carbon paste by screen printing or the like.

[0069] The battery element may be in the form of a cell stack having a plurality of unit cells, each including a positive electrode layer 12, a separator 20, and a negative electrode layer 16. The cell stack is not limited to a flat plate stack structure in which flat plates or layers are stacked, but may have various stack structures, including the following examples. In any of the configurations exemplified below, it is preferable that the entire cell stack be a single, integral sintered body. - Folded structure: A laminated structure in which a sheet having a layered configuration including a unit cell and a current collecting layer is folded once or multiple times to form a multilayer (large area) structure. - Wound structure: A laminated structure in which sheets of a layer configuration including a unit cell and a current collecting layer are wound and integrated to form a multilayer (large area) structure. - Multilayer ceramic capacitor (MLCC)-like structure: A multilayer structure (large area) in which stacked units of current collecting layer / positive electrode layer / ceramic separator layer / negative electrode layer / current collecting layer are repeated in the thickness direction, and multiple positive electrode layers collect current on one side (e.g., the left side) and multiple negative electrode layers collect current on the other side (e.g., the right side).

[0070] <Example>

[0071] Several specific examples of this embodiment will be described. In the following examples, LiCoO2 is abbreviated as "LCO" and Li4Ti5O 12 shall be abbreviated as "LTO."

[0072] <<Example 1>>

[0073] (1) Preparation of LCO green sheet (positive electrode green sheet)

[0074] First, Co3O4 powder (manufactured by Seido Chemical Industry Co., Ltd.) and Li2CO3 powder (manufactured by Honjo Chemical Co., Ltd.) were mixed at a Li / Co molar ratio of 1.01 and then heated to 780 °C for 5 hours. The resulting powder was then ground in a pot mill to a volumetric D50 of 0.4 μm to obtain a powder consisting of LCO platelet particles. One hundred parts by weight of the resulting LCO powder was mixed with 100 parts by weight of a dispersion medium (toluene:isopropanol = 1:1), 10 parts by weight of a binder (polyvinyl butyral, product number BM-2, manufactured by Sekisui Chemical Co., Ltd.), 4 parts by weight of a plasticizer (DOP: Di(2-ethylhexyl)phthalate, manufactured by Kurogane Kasei Co., Ltd.), and 2 parts by weight of a dispersant (Rheodor SP-O30, manufactured by Kao Corporation). The resulting mixture was stirred under reduced pressure to degas and adjust the viscosity to 4000 cP to prepare an LCO slurry. The viscosity was measured using a Brookfield LVT viscometer. The slurry was then formed into a sheet on a PET film using a doctor blade method to form an LCO green sheet. The thickness of the LCO green sheet was adjusted to 60 μm after firing.

[0075] (2) Preparation of LTO green sheet (negative electrode green sheet)

[0076] First, 100 parts by weight of LTO powder (volume-based D50 particle size: 0.06 μm, manufactured by Sigma-Aldrich Japan LLC), 100 parts by weight of a dispersion medium (toluene:isopropanol = 1:1), 20 parts by weight of a binder (polyvinyl butyral: product number BM-2, manufactured by Sekisui Chemical Co., Ltd.), 4 parts by weight of a plasticizer (DOP: Di(2-ethylhexyl)phthalate, manufactured by Kurogane Kasei Co., Ltd.), and 2 parts by weight of a dispersant (product name Rheodor SP-O30, manufactured by Kao Corporation) were mixed. The resulting anode raw material mixture was stirred under reduced pressure to degas and the viscosity was adjusted to 4000 cP to prepare an LTO slurry. The viscosity was measured using a Brookfield LVT viscometer. The prepared slurry was then formed into a sheet on a PET film using a doctor blade method to form an LTO green sheet. The LTO green sheet was adjusted to a thickness of 70 μm after firing.

[0077] (3) Preparation of MgO green sheets (separator green sheets)

[0078] Magnesium carbonate powder (manufactured by Konoshima Chemical Co., Ltd.) was heat-treated at 900°C for 5 hours to obtain MgO powder. The resulting MgO powder was mixed with glass frit (manufactured by Nippon Frit Co., Ltd., CK0199) at a weight ratio of 4:1. 100 parts by weight of the resulting mixed powder (volume-based D50 particle size 0.4 μm), 100 parts by weight of a dispersion medium (toluene:isopropanol = 1:1), 20 parts by weight of a binder (polyvinyl butyral, product number BM-2, manufactured by Sekisui Chemical Co., Ltd.), 4 parts by weight of a plasticizer (DOP: Di(2-ethylhexyl)phthalate, manufactured by Kurogane Kasei Co., Ltd.), and 2 parts by weight of a dispersant (product name Rheodor SP-O30, manufactured by Kao Corporation). The resulting raw material mixture was stirred under reduced pressure to degas and the viscosity was adjusted to 4000 cP to prepare a slurry. The viscosity was measured using a Brookfield LVT viscometer. The slurry thus prepared was formed into a sheet on a PET film by a doctor blade method to form a separator green sheet, which had a thickness of 25 μm after firing.

[0079] (4) Lamination, compression and firing

[0080] An LCO green sheet (positive electrode green sheet), an MgO green sheet (separator green sheet), and an LTO green sheet (negative electrode green sheet) were stacked in this order, and the resulting laminate was pressed by cold isostatic pressing (CIP) at 200 kgf / cm² to bond the green sheets together. The bonded laminate was then punched into a 10 mm diameter disk using a punching die. The resulting disk-shaped laminate was degreased at 600°C for 5 hours, then heated to 800°C at 1000°C / h and held there for 10 minutes, after which it was cooled. This resulted in a single integrated sintered plate containing three layers: a positive electrode layer (LCO sintered compact layer), a ceramic separator (MgO separator), and a negative electrode layer (LTO sintered compact layer).

[0081] (5) Fabrication of lithium-ion secondary batteries

[0082] A coin-type lithium ion secondary battery 10 as shown schematically in FIG. 1 was fabricated as follows.

[0083] (5a) Bonding of the negative electrode layer and negative electrode current collector with conductive carbon paste

[0084] Acetylene black and polyimide amide were weighed out in a mass ratio of 3:1 and mixed with an appropriate amount of NMP (N-methyl-2-pyrrolidone) as a solvent to prepare a conductive carbon paste as a conductive adhesive. The conductive carbon paste was screen-printed onto aluminum foil as a negative electrode current collector. The integrated sintered body prepared in (4) above was placed so that the negative electrode layer was contained within the undried printed pattern (i.e., the area coated with the conductive carbon paste). This was then vacuum-dried at 60°C for 30 minutes to produce a structure in which the negative electrode layer and negative electrode current collector were bonded via the negative electrode-side carbon layer. The thickness of the negative electrode-side carbon layer was 10 μm.

[0085] (5b) Preparation of a positive electrode current collector with a carbon layer

[0086] Acetylene black and polyimide amide were weighed out in a mass ratio of 3:1 and mixed with an appropriate amount of NMP (N-methyl-2-pyrrolidone) as a solvent to prepare a conductive carbon paste. The conductive carbon paste was screen-printed onto an aluminum foil positive electrode current collector, and then vacuum-dried at 60°C for 30 minutes to produce a positive electrode current collector with a positive electrode carbon layer formed on the surface. The thickness of the positive electrode carbon layer was 5 μm. (5c) Coin cell battery assembly

[0087] The positive electrode current collector, positive electrode carbon layer, integrated sintered body plate (LCO positive electrode layer, MgO separator, and LTO negative electrode layer), negative electrode carbon layer, and negative electrode current collector were stacked in this order between the positive electrode can and negative electrode can, which would form the battery case. After filling with electrolyte, the positive electrode can and negative electrode can were sealed by crimping them together with a gasket. In this way, a coin-cell-type lithium-ion secondary battery 10 with a diameter of 12 mm and a thickness of 1.0 mm was fabricated. The electrolyte used was a solution prepared by dissolving LiBF4 at a concentration of 1.5 mol / L in an organic solvent mixture of ethylene carbonate (EC) and gamma-butyrolactone (GBL) in a volume ratio of 1:3.

[0088] (6) Measurement of capacity retention rate after storage

[0089] The post-storage capacity retention of the battery was measured using the following procedure. First, the battery was charged at a constant voltage of 2.7 V in a 25°C environment, and then discharged at a discharge rate of 0.2 C to measure the initial capacity. Next, the battery was held for 50 days in a 60°C environment with a voltage of 2.7 V applied. Finally, the post-storage capacity was measured by charging at a constant voltage of 2.7 V, and then discharging at 0.2 C. The post-storage capacity retention (%) was obtained by dividing the measured post-storage capacity by the initial capacity and multiplying the result by 100.

[0090] (7) Dismantle, clean and reassemble the battery after storage

[0091] After storage, the battery was prepared, and the seal between the positive and negative cans was opened. The negative can and gasket were then removed from the battery, and the positive current collector, integrated sintered plate, and negative current collector were removed from the battery. The positive current collector was then removed from the integrated sintered plate, and the integrated sintered plate with the negative current collector attached was immersed in an appropriate amount of NMP (N-methyl-2-pyrrolidone) and stirred for 60 minutes to dissolve and remove the positive and negative carbon layers attached to the integrated sintered plate, as well as impurities such as electrolyte decomposition products attached to the integrated sintered plate. At the same time, the negative current collector was peeled off. This process was repeated twice, and the integrated sintered plate from which the impurities had been removed was vacuum-dried at 120°C for 12 hours. The vacuum-dried integrated sintered plate was then reassembled into a coin-type battery using the above procedures (5a), (5b), and (5c).

[0092] (8) Capacity retention rate of reassembled batteries

[0093] The capacity retention rate of the reassembled battery was measured using the following procedure. First, the battery was charged at a constant voltage of 2.7 V in a 25°C environment, and then discharged at a discharge rate of 0.2 C to measure the capacity after reassembly. The measured capacity after reassembly was divided by the initial capacity and multiplied by 100 to obtain the capacity retention rate (%) after reassembly.

[0094] <<Example 2>>

[0095] The reassembled battery was evaluated in the same manner as in Example 1, except that the vacuum-dried integrated sintered plate was degreased by heating at 600° C. for 5 hours and then used for reassembling the battery.

[0096] <<Example 3>>

[0097] The reassembled battery was evaluated in the same manner as in Example 2, except that the degreased integral sintered plate was fired at 800° C. for 10 minutes and then used to reassemble the battery.

[0098] <<Example 4 (Comparison)>>

[0099] The reassembled battery was evaluated in the same manner as in Example 1, except that the electrolyte solution was only replaced without carrying out electrode restoration treatment (cleaning and drying) after disassembly of the battery.

[0100] <<Example 5 (Comparison)>>

[0101] A battery was fabricated, and the subsequent steps and evaluation were carried out in the same manner as in Example 1, except that a) a commercially available LCO coated electrode (manufactured by Hosen Co., Ltd.) was used as the positive electrode plate instead of an LCO sintered plate, b) a carbon-coated electrode on a negative electrode current collector prepared by the procedure described below was used as the negative electrode plate and negative electrode current collector, and c) a cellulose separator was used as the separator. (Preparation of carbon-coated electrodes)

[0102] A paste containing a mixture of graphite as the active material and polyvinylidene fluoride (PVDF) as a binder was applied to the surface of a negative electrode current collector (aluminum foil) and dried to produce a carbon-coated electrode with a 280 μm-thick carbon layer.

[0103] <<Evaluation Results>>

[0104] Table 1 shows the evaluation results of Examples 1 to 5. [Table 1]

[0105] As can be seen from the results shown in Table 1, in Examples 1 to 3, the electrode restoration treatment resulted in a significant recovery in the capacity retention rate due to the effect of removing impurities, etc. On the other hand, in Example 4, a comparative example in which only the electrolyte solution was replaced, no significant improvement in the capacity retention rate was observed. Furthermore, in Example 5, a comparative example in which a coated electrode (containing a binder, etc.) was used, deterioration occurred due to the detachment of the active material during the washing process.

[0106] The above is a description of an example of a lithium ion secondary battery having ceramic electrodes and an example of a method for reusing the lithium ion secondary battery.

[0107] Referring to Figures 5 and 6, using an electric vehicle (EV) as an example, a value chain according to a comparative example based on the assumption that conventional lithium-ion secondary batteries are reused, and an expected value chain for the reuse of lithium-ion secondary batteries according to this embodiment will be described.

[0108] As shown in Figure 5, in the value chain according to the comparative example, the EV is returned by the user to the dealer, and then the dealer sends the EV to a dismantler. The dismantler dismantles the EV, removes the lithium-ion secondary battery, and sends the removed lithium-ion secondary battery to a recycler. The recycler dismantles the lithium-ion secondary battery. incineration The metal is extracted and sent to a cathode material manufacturer, who can use the extracted metal to synthesize raw materials for active materials.

[0109] As described above, according to one comparative example, each lithium ion secondary battery is incinerated, and metal elements are extracted and recycled, which is a complicated process and therefore expensive.

[0110] Furthermore, according to one comparative example, the current collector prevents the electrolyte from moving between the electrode layers, making it difficult for the electrolyte to be discharged and penetrated.

[0111] On the other hand, in this embodiment, a value chain illustrated in Fig. 6 is expected. The main differences from the comparative example are as follows. For ease of explanation, the lithium ion secondary battery according to this embodiment (lithium ion secondary battery having ceramic electrodes) may be simply referred to as a "battery" hereinafter. (A) The degree of battery deterioration is diagnosed for a used EV battery returned to a dealer by the user. The owner of the battery may be the user or a party other than the user (for example, the battery in the EV may be leased). In this embodiment, a "used battery" refers to a battery that is not a new battery, that is, a battery that has been used even a little. (B) If the battery's degradation level is less than a predetermined value, the battery is regenerated. Specifically, the battery's electrolyte is replaced. This battery does not have a current collector, which allows for easy permeation, making it easy to replace the electrolyte. (C) If the degree of deterioration of the battery is equal to or greater than a predetermined value, the degree of deterioration of the ceramic electrodes of the battery is diagnosed. If the degree of deterioration is such that they can be regenerated, the ceramic electrodes are subjected to a regeneration process, and then the battery is assembled. Since the electrodes are ceramic electrodes and can be removed as they are, they can be regenerated. If the degree of deterioration of the ceramic electrodes of the battery is not such that they can be regenerated, the electrodes are crushed, etc., and then the active material is synthesized, and the electrodes and battery are assembled.

[0112] In this embodiment, a reuse support system is constructed as a computer system for supporting the reuse of batteries. The reuse support system may be a physical computer system (one or more computers), or may be a logical computer system (e.g., a system as a cloud computing service) based on a physical computer system (e.g., a cloud platform having multiple types of computing resources).

[0113] This embodiment will be described in more detail below. In the following description, the ceramic positive electrode layer 12 will be taken as an example of the ceramic electrode. Because the ceramic electrode can be removed for reuse, in the following description, the ceramic positive electrode layer 12 will be referred to as the "ceramic positive electrode 12." The ceramic negative electrode layer 16 can also be referred to as the "ceramic negative electrode 16." The ceramic negative electrode layer 16 may be used as the ceramic electrode instead of or in addition to the ceramic positive electrode 12. In addition, the ceramic electrodes (ceramic positive electrode 12 and / or ceramic negative electrode 16) may have primary particles whose crystals are oriented at a specific angle, or the primary particles may be random (not oriented at a specific angle).

[0114] FIG. 7 is a diagram showing the overall configuration of a reuse system including a reuse support system according to this embodiment.

[0115] The reuse system includes one or more diagnostic support devices and a reuse support system 750. The diagnostic support device is a device that obtains diagnostic data, which is data used to diagnose the lithium ion secondary battery 10 or the ceramic positive electrode 12 (specifically, the ceramic positive electrode 12 removed from the battery 10), by methods such as imaging, measurement, inspection, or analysis. The reuse support system 750 typically receives the diagnostic data obtained by each of the one or more diagnostic support devices via a communication network 730. The communication network 110 is, for example, the Internet, a wide area network (WAN), or a local area network (LAN).

[0116] The diagnostic support device may be a device that obtains diagnostic data for the ceramic positive electrode 12. Furthermore, the diagnostic support device may be a device that obtains diagnostic data used to diagnose the degradation mode of the battery 10 (diagnosing whether the degradation is in the electrodes or the electrolyte).

[0117] The "diagnosis" of the ceramic positive electrode 12 includes determining the degree of deterioration and determining the contents of the regeneration treatment, which will be described later. At least one of a camera 711 and a balance 712 (an example of a weight measuring device) is used as a diagnostic support device for determining the degree of deterioration. At least one of a stereomicroscope 713, a hardness tester 714, an X-ray CT device 715, and an X-ray diffraction device 716 is used as a diagnostic support device for determining the contents of the regeneration treatment.

[0118] As the diagnosis support device, other types of diagnosis support devices may be adopted instead of or in addition to at least some of the above-mentioned diagnosis support devices. Data obtained by the diagnosis support device may be input to the reuse support system 750 by any of the following methods (or other methods). The diagnostic support device has a communication function. The communication function transmits data. The transmitted data is sent to the reuse support system 750 via the communication network 730, with or without going through an edge device such as a gateway device. An information processing terminal (for example, a personal computer or a smartphone) receives data from the diagnosis support device (or accepts input of data representing the results of measurements, etc., performed by the diagnosis support device from an operator), and transmits the data to the reuse support system 750 via or without the communication network 730. The information processing terminal may be, for example, an operator terminal 760, which will be described later.

[0119] Furthermore, data for diagnosing the degree of deterioration of the battery 10 itself may not be input to the reuse support system 750, but may be measured on-site, such as at a dealer, and the degree of deterioration of the battery 10 may be diagnosed. In this embodiment, battery diagnosis (e.g., S901 in FIG. 9 , described later) for diagnosing the degree of deterioration of the battery 10 is performed by the reuse support system 750. For example, an IoT device (not shown) for diagnosing the degree of deterioration of the battery 10 may be provided in the battery 10. The IoT device may transmit diagnostic data indicating a degradation index value of the battery 10 to the reuse support system 750, and the reuse support system 750 may perform battery diagnosis based on the diagnostic data. Note that the "degradation index value" is a value obtained for the battery 10 as an index of the degradation state of the battery 10. The degradation index value may be a value measured for the battery 10, or a value calculated based on a value measured for the battery 10. Specifically, for example, the degradation index value may be at least one of the resistance value (internal resistance value) of the battery 10, the output current value, and the time until the voltage drops. Furthermore, instead of the reuse support system 750 performing the battery diagnosis, the IoT device may perform the battery diagnosis and transmit data indicating the diagnosis result (whether or not the deterioration is significant) to the reuse support system 750.

[0120] Of the reuse support system 750 (e.g., a server) and an operator terminal 760 (e.g., a client) which is an information processing terminal used to operate the reuse support system 750, for example, the operator terminal 760 exists in a company that provides a reuse support service. The reuse support system 750 performs at least an electrode diagnosis out of a battery diagnosis and an electrode diagnosis in response to an instruction from the operator terminal 760 (or automatically without such an instruction).

[0121] FIG. 8 is a diagram showing the configuration of the reuse support system 750.

[0122] The reuse support system 750 includes an interface device 801, a storage device 802, and a processor 803 connected thereto.

[0123] Data is transmitted and received via the interface device 801. For example, diagnostic data is received, Reception The obtained data is stored in the storage device 802.

[0124] The storage device 802 stores programs and data. The stored data includes, for example, battery diagnostic data 809 (data representing a deterioration index value of the battery 10) for battery diagnosis, diagnostic data 810 for a deterioration mode, and diagnostic data for electrode diagnosis. The diagnostic data for electrode diagnosis includes, for example, the following (A) and (B). (A) At least one type of data among camera image data 811 and weight data 812 (an example of one or more types of first data). (B) At least one type of data among microscope image data 813, hardness data 814, X-ray CT data 815, and X-ray diffraction data 816 (one or more types of second data).

[0125] The camera image data 811 is data representing an image captured by the camera 711 (a captured image of the removed ceramic positive electrode 12). The weight data 812 is data representing the weight measured by the balance 712 (the weight of the removed ceramic positive electrode 12). The microscope image data 813 is data representing an image captured by the stereomicroscope 713 (an image of the outermost surface of the removed ceramic positive electrode 12). The hardness data 814 is data representing the hardness measured by the hardness tester 714 (the hardness of the removed ceramic positive electrode 12). The X-ray CT data 815 is data representing an image captured by the X-ray CT device 715 (an image of the internal structure of the removed ceramic positive electrode 12). The X-ray diffraction data 816 is data representing the results of X-ray diffraction by the X-ray diffractometer 716 (for example, data representing at least one of the crystal structure, crystallinity, and heterophase identification of the outermost surface of the ceramic positive electrode 12).

[0126] The processor 803 executes the program to realize functions such as a battery diagnosis unit 830, a deterioration mode diagnosis unit 840, and an electrode diagnosis unit 850.

[0127] The battery diagnostic unit 830 performs a battery diagnosis, specifically, determines the degree of deterioration of the battery 10, based on the battery diagnostic data 809.

[0128] The deterioration mode diagnosis unit 840 determines whether the deterioration mode of the battery 10 is due to the ceramic positive electrode 12 or the electrolyte, based on the deterioration mode diagnosis data 810.

[0129] The electrode diagnosis unit 850 performs electrode diagnosis based on at least one type of data from the data 811 to 816. Specifically, the electrode diagnosis unit 850 has an electrode deterioration diagnosis unit 851 and a regeneration treatment content determination unit 852. The electrode deterioration diagnosis unit 851 performs electrode deterioration determination, which is a determination of whether the degree of deterioration of the extracted ceramic positive electrode layer 12 satisfies the conditions for regenerating the ceramic electrode layer, based on at least one type of data from the data 811 and 812. The regeneration treatment content determination unit 852 evaluates one or more evaluation items of the ceramic electrode layer based on the data 813 to 816, and determines the content of the regeneration treatment to be performed on the extracted ceramic positive electrode layer 12 based on the evaluation results for the one or more evaluation items.

[0130] The flow of battery reuse carried out in this embodiment will be described below.

[0131] 9 is a flowchart showing the flow of recycling the battery 10. Note that the processes S951 to S957 represented by the blocks arranged in the area represented by the reference numeral 950 are performed by at least one of a system other than the reuse support system 750 and human beings.

[0132] The battery diagnostic unit 830 determines whether the degree of deterioration of the battery 10 exceeds a predetermined level based on the battery diagnostic data 809 (S901). If the determination result of S901 is false (S901: No), the battery diagnostic unit 830 decides to reuse the battery 10 (S902) and transmits, for example, the determination result of S901 or information indicating the decision to reuse the battery 10 to the operator terminal 760. In this case, the battery 10 is reused as is (or after predetermined maintenance has been performed) (S957).

[0133] If the judgment result of S901 is true (S901: Yes), the deterioration mode diagnosis unit 840 determines whether the deterioration mode of the battery 10 is the ceramic positive electrode 12 (i.e., the electrolyte) based on the deterioration mode diagnosis data 810 (S903).

[0134] If the determination result of S903 is false (S903: No), the degradation mode diagnosis unit 840 decides to replace the electrolyte (S904) and transmits, for example, the determination result of S903 or information indicating the decision to replace the electrolyte to the operator terminal 760. In this case, the electrolyte is replaced (S951), and then the battery 10 is reused (S957).

[0135] If the determination result of S903 is true (S903: Yes), the deterioration mode diagnosis unit 840 determines to remove the ceramic positive electrode 12 (S905) and transmits, for example, the determination result of S903 or information indicating the determination to remove the ceramic positive electrode 12 to the operator terminal 760. In this case, the battery 10 is disassembled and the ceramic positive electrode 12 is removed (S952). Electrode diagnosis is performed on the ceramic positive electrode 12 removed from the battery 10. Note that the electrode diagnosis may be performed on the ceramic positive electrode 12 removed from the battery 10 and further subjected to a predetermined process (e.g., cleaned). That is, in the following description, the "removed ceramic positive electrode 12" may refer to the ceramic positive electrode 12 that has been subjected to cleaning and / or other processes after removal.

[0136] When the electrode diagnostic unit 850 recognizes that the ceramic positive electrode 12 has been removed based on data from the sensor or the operator terminal 760 (S906: Yes), the electrode deterioration determination unit 851 of the electrode diagnostic unit 850 performs an electrode deterioration determination, which is a determination of whether the degree of deterioration of the removed ceramic positive electrode layer 12 satisfies the conditions for regenerating the ceramic electrode layer, based on at least one type of data 811 and 812 (S907).

[0137] If the determination result in S907 is true (S907: Yes), the regeneration process content determination unit 852 evaluates one or more evaluation items of the ceramic electrode layer based on the data 813 to 816, and determines the content of the regeneration process to be performed on the extracted ceramic positive electrode layer 12 based on the evaluation results for the one or more evaluation items (S908). For example, the regeneration process content determination unit 852 transmits information indicating the determined content of the regeneration process to at least one of the operator terminal 760 and a device (not shown) that performs the regeneration process. In this case, the regeneration process according to the determined content is performed on the ceramic positive electrode 12 (S953). Thereafter, a battery 10 including the ceramic positive electrode 12 is assembled (S954), and the battery 10 is reused (S957).

[0138] If the determination result of S907 is false (S907: No), the electrode deterioration determination unit 851 decides to crush the battery 10 (S909) and transmits, for example, the determination result of S907 or information indicating the decision to crush the battery 10 to the operator terminal 760. In this case, the crushing process of the battery 10 is performed (S955), the battery 10 is manufactured (S956), and the battery 10 is reused (S957).

[0139] FIG. 10 is a flowchart showing the details of S907 in FIG.

[0140] The electrode deterioration determination unit 851 determines whether the degree of adhesion to the ceramic positive electrode 12 is less than a predetermined level based on the camera image data 811 (S1001).

[0141] If the determination result of S1001 is false (S1001: No), the determination result of S907 is false, and as a result, S909 is performed. In this case, for example, electrode deterioration determination unit 851 may decide to forcibly remove the attached matter in S909.

[0142] If the determination result in S1001 is true (S1001: Yes), the electrode deterioration determination unit 851 determines whether the weight represented by the weight data 812 is equal to or greater than a predetermined weight (S1002). The determination in S1002 is, for example, to determine whether the ceramic positive electrode 12 is maintained (whether there is no damage) by removing and cleaning the ceramic positive electrode 12. The determinations in S1001 and S1002 may be performed in parallel, or S1002 may be performed first.

[0143] If the determination result in S1002 is false (S1002: No), the determination result in S907 is false, and as a result, S909 is performed.

[0144] If the determination result in S1002 is true (S1002: Yes), the determination result in S907 is true, and S908 is performed.

[0145] FIG. 11 is a flowchart showing the details of S908 in FIG.

[0146] The recycling process content determination unit 852 performs surface evaluation (S1101), hardness evaluation (S1102), structure evaluation (S1103), and diffraction evaluation (S1104).

[0147] The surface evaluation (S1101) is performed based on the microscope image data 813. The microscope image data 813 is data representing an image of the outermost surface of the removed ceramic positive electrode 12 taken with a microscope. The surface evaluation is performed based on the results of observing the microstructure of the outermost surface of the ceramic positive electrode 12. For example, the degree of cracking on the outermost surface of the ceramic positive electrode 12 is evaluated.

[0148] The hardness evaluation (S1102) is performed based on the hardness data 814. The hardness data 814 is data representing the hardness (hardness of the extracted ceramic positive electrode 12) measured by the hardness tester 714. The hardness data 814 represents, for example, the behavior of the ceramic positive electrode 12 when a predetermined member is pressed into the ceramic positive electrode 12 and the size of the mark (e.g., hole) that occurs as a result of the pressing. The hardness is evaluated.

[0149] The structural evaluation (S1103) is performed based on the X-ray CT data 815. The X-ray CT data 815 is data representing an image (an image of the internal structure of the extracted ceramic positive electrode 12) captured by the X-ray CT device 715. The X-ray CT data 815 corresponds to visualized data of the internal microstructure of the ceramic positive electrode 12, and the degree of internal cracking of the ceramic positive electrode 12 is evaluated based on this data.

[0150] The diffraction evaluation (S1104) is performed based on the X-ray diffraction data 816. The X-ray diffraction data 816 is data representing the results of X-ray diffraction by the X-ray diffractometer 716 (for example, data representing at least one of the crystal structure, crystallinity, and heterophase identification of the outermost surface of the ceramic positive electrode 12). Based on the X-ray diffraction data 816, at least one of the crystal structure, crystallinity, and heterophase identification of the outermost surface of the ceramic positive electrode 12 is evaluated.

[0151] The regeneration process content determination unit 852 determines the content of the regeneration process to be performed on the ceramic positive electrode 12 based on the evaluation results of S1101 to S1104 (S1105). For example, the regeneration process content determination unit 852 estimates the degree of reduction of Li and the degree of reduction of Me (constituent metal elements such as Co and Ni) based on the evaluation results of S1101 to S1104, and determines a set of process parameters for the ceramic positive electrode 12 corresponding to the estimated degree of reduction of Li and Me (constituent metal elements such as Co and Ni) (for example, selects a parameter set corresponding to the estimated degree of reduction of Li and Me (constituent metal elements such as Co and Ni) from among multiple process parameter sets). The "set of process parameters" refers to one or more parameters for each of one or more types of processes in the regeneration process, such as parameters related to impregnation with a Li-Me solution (e.g., concentration and molar ratio) and parameters related to heat treatment (e.g., temperature and time).

[0152] Although one embodiment has been described above, this is merely an example for explaining the present invention, and the scope of the present invention is not limited to this embodiment. The above description can be expressed, for example, as follows.

[0153] [Expression 1] an electrode deterioration determination unit that performs electrode deterioration determination, which is a determination as to whether or not the degree of deterioration of the ceramic electrode removed from the lithium ion secondary battery satisfies a condition for regenerating the ceramic electrode, based on one or more types of first data obtained by diagnosing the ceramic electrode removed from the lithium ion secondary battery having the ceramic electrode; A reuse support system.

[0154] [Expression 2] If the result of the electrode deterioration determination is true, a regeneration treatment content determination unit evaluates one or more evaluation items of the ceramic electrode based on one or more types of second data input about the extracted ceramic electrode, and determines the content of the regeneration treatment to be performed on the extracted ceramic electrode based on the evaluation results about the one or more evaluation items. The reuse support system according to expression 1.

[0155] [Expression 3] the one or more types of first data include photographed image data of the extracted ceramic electrode, the electrode deterioration determination includes determining whether or not a degree of adhesion to the extracted ceramic electrode is less than a predetermined degree based on the captured image data; The result of the determination being false means that the result of the electrode deterioration determination is false. A reuse support system according to expression 1 or 2.

[0156] [Expression 4] the one or more types of first data include weight data that is data representing a weight measured for the extracted ceramic electrode; the electrode deterioration determination includes determining whether the weight represented by the weight data is equal to or greater than a predetermined weight; The result of the determination being false means that the result of the electrode deterioration determination is false. A reuse support system according to any one of expressions 1 to 3.

[0157] [Expression 5] The one or more types of second data include at least one type of data from the following: (a) data representing a microscopic image of the outermost surface of the removed ceramic electrode; (b) data representing the hardness of the extracted ceramic electrode; (c) data representing an X-ray CT image of the extracted ceramic electrode; (d) data showing the results of X-ray diffraction of the extracted ceramic electrode; The reuse support system according to expression 2.

[0158] [Expression 6] a deterioration mode determination unit that determines whether the deterioration mode of the lithium ion secondary battery is an electrode or an electrolyte; and When it is determined that the deterioration mode is due to the electrolyte, the electrolyte of the lithium ion secondary battery is replaced; When it is determined that the deterioration mode is an electrode deterioration mode, the electrode deterioration determination unit Electrode deterioration determination To do A reuse support system according to any one of expressions 1 to 5.

[0159] [Expression 7] a lithium ion secondary battery having a ceramic electrode; A reuse support system according to any one of expressions 1 to 6. A reuse system comprising:

[0160] [Expression 8] a computer performs an electrode deterioration determination based on one or more types of first data input about a ceramic electrode removed from a lithium ion secondary battery having a ceramic electrode that is an electrode using a crystal-oriented ceramic plate, to determine whether the degree of deterioration of the removed ceramic electrode satisfies the conditions for regenerating the ceramic electrode; When the result of the electrode deterioration determination is true, the computer evaluates one or more evaluation items of the ceramic electrode based on one or more types of second data input about the extracted ceramic electrode, and determines the content of the regeneration treatment to be performed on the extracted ceramic electrode based on the evaluation results about the one or more evaluation items. Reuse support method. [Explanation of symbols]

[0161] 750...Reuse Support System

Claims

1. an electrode deterioration determination unit that performs electrode deterioration determination, which is a determination as to whether or not the degree of deterioration of the extracted ceramic electrode satisfies a condition for regenerating the ceramic electrode, based on one or more types of first data obtained by diagnosing the ceramic electrode extracted from a lithium ion secondary battery having the ceramic electrode; a regeneration treatment content determination unit that, when the result of the electrode deterioration determination is true, evaluates one or more evaluation items of the ceramic electrode based on one or more types of second data input about the extracted ceramic electrode, and determines the content of a regeneration treatment to be performed on the extracted ceramic electrode based on the evaluation results about the one or more evaluation items; A reuse support system having:

2. The one or more types of second data include at least one type of data: (a) data representing a microscope image of the outermost surface of the removed ceramic electrode; (b) data representing the hardness of the extracted ceramic electrode; (c) data representing an image of the extracted ceramic electrode taken by X-ray CT; (d) data showing the results of X-ray diffraction of the extracted ceramic electrode; The reuse support system according to claim 1 .

3. an electrode deterioration determination unit that performs electrode deterioration determination, which is a determination as to whether or not the degree of deterioration of the ceramic electrode taken out from the lithium ion secondary battery satisfies the condition for restoring the ceramic electrode, based on one or more types of first data obtained by diagnosing the ceramic electrode taken out from the lithium ion secondary battery having the ceramic electrode; and the one or more types of first data include weight data that is data representing a weight measured for the extracted ceramic electrode; the electrode deterioration determination includes determining whether the weight represented by the weight data is equal to or greater than a predetermined weight; The result of the determination being false means that the result of the electrode deterioration determination is false. Reuse support system.

4. the one or more types of first data include photographed image data of the extracted ceramic electrode, the electrode deterioration determination includes determining whether or not a degree of adhesion to the extracted ceramic electrode is less than a predetermined degree based on the captured image data; The result of the determination being false means that the result of the electrode deterioration determination is false. The reuse support system according to claim 1 .

5. The one or more types of first data include photographed image data of the extracted ceramic electrode, the electrode deterioration determination includes determining whether or not a degree of adhesion to the extracted ceramic electrode is less than a predetermined degree based on the captured image data; The result of the determination being false means that the result of the electrode deterioration determination is false. The reuse support system according to claim 3 .

6. a deterioration mode determination unit that determines whether the deterioration mode of the lithium ion secondary battery is an electrode or an electrolyte; and When it is determined that the deterioration mode is due to the electrolyte, the electrolyte of the lithium ion secondary battery is replaced, When it is determined that the deterioration mode is an electrode deterioration mode, the electrode deterioration determination unit performs the deterioration degree determination. The reuse support system according to claim 1 .

7. A degradation mode determination unit that determines whether the degradation mode of the lithium ion secondary battery is an electrode or an electrolyte. and When it is determined that the deterioration mode is due to the electrolyte, the electrolyte of the lithium ion secondary battery is replaced, When it is determined that the deterioration mode is an electrode deterioration mode, the electrode deterioration determination unit performs the deterioration degree determination. The reuse support system according to claim 3 .

8. a lithium ion secondary battery having a ceramic electrode; The reuse support system according to any one of claims 1 to 7, A reuse system comprising:

9. a computer performs an electrode deterioration determination, which is a determination as to whether or not the degree of deterioration of the ceramic electrode taken out from the lithium ion secondary battery, based on one or more types of first data diagnosed on the ceramic electrode taken out from the lithium ion secondary battery having the ceramic electrode, satisfies a condition for regenerating the ceramic electrode; When the result of the electrode deterioration determination is true, the computer evaluates each of one or more evaluation items of the ceramic electrode based on one or more types of second data input about the extracted ceramic electrode, and determines the content of a regeneration treatment to be performed on the extracted ceramic electrode based on the evaluation results about the one or more evaluation items. Reuse support method.

10. a computer performs an electrode deterioration determination, which is a determination as to whether or not the degree of deterioration of the ceramic electrode taken out from the lithium ion secondary battery having the ceramic electrode satisfies a condition for regenerating the ceramic electrode, based on one or more types of first data obtained by diagnosing the ceramic electrode taken out from the lithium ion secondary battery having the ceramic electrode; the one or more types of first data include weight data that is data representing a weight measured for the extracted ceramic electrode; the electrode deterioration determination includes determining whether the weight represented by the weight data is equal to or greater than a predetermined weight; The result of the determination being false means that the result of the electrode deterioration determination is false. Reuse support method.

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