JP6853954B2 - Manufacturing method of non-aqueous electrolyte secondary battery - Google Patents

Description

The present invention relates to a method for manufacturing a non-aqueous electrolyte secondary battery.

For non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries, further improvement in durability is being studied as part of performance improvement. Such an improvement in durability is realized, for example, by causing a more homogeneous charge / discharge reaction in the electrode.
In this regard, for example, Patent Document 1 discloses a method for manufacturing a non-aqueous electrolyte secondary battery having a positive electrode and a negative electrode wider than the positive electrode. In Patent Document 1, when the negative electrode is produced, the drying conditions are adjusted so that the solvent evaporates more slowly at both end portions in the width direction than in the central portion in the width direction. As a result, the concentration of the binder at the central portion in the width direction of the negative electrode is made larger than the concentration of the binder at both end portions in the width direction. According to Patent Document 1, such a configuration can reduce the difference in charge / discharge reactivity in the width direction of the negative electrode and improve the durability of the battery.

Japanese Unexamined Patent Publication No. 2013-225440 Japanese Unexamined Patent Publication No. 2016-139574 Japanese Unexamined Patent Publication No. 2016-149243

In Patent Document 1, the charge / discharge reactivity in the width direction of the negative electrode is adjusted by adjusting the drying conditions. Therefore, it is difficult to adjust the charge / discharge reactivity of the negative electrode with good reproducibility and high accuracy.
Further, Patent Documents 2 and 3, which are prior applications of the present inventor, disclose a technique for adjusting charge / discharge reactivity using X-rays at the time of manufacturing an electrode. However, in such a method, the time required for manufacturing the electrode becomes long due to the addition of steps. Therefore, from the viewpoint of productivity, a more efficient method is required.

The present invention has been made in view of such circumstances, and an object of the present invention is to adjust the charge / discharge reactivity of the negative electrode with good reproducibility and high accuracy, and also to have excellent productivity. The purpose is to provide a method for manufacturing a next battery.

INDUSTRIAL APPLICABILITY The present invention provides a method for producing a non-aqueous electrolyte secondary battery. In this manufacturing method, the next step: an electrode body in which a positive electrode containing a positive electrode active material and a negative electrode containing a carbon material as a negative electrode active material are arranged to face each other in an insulated state and a non-aqueous electrolyte are prepared. Preparation step; A construction step of accommodating the electrode body and the non-aqueous electrolyte inside a battery case having X-ray transmission to construct a battery assembly; and the negative electrode from the outside of the battery case. Includes an irradiation step of reducing the charge / discharge reactivity of the carbon material at the predetermined portion by irradiating the X-ray toward the predetermined portion of the above.

According to such a manufacturing method, the charge / discharge reactivity of the carbon material at the X-ray irradiation site can be selectively adjusted. At this time, by using X-rays, the charge / discharge reactivity of the negative electrode can be adjusted with high reproducibility and high accuracy as compared with, for example, the method described in Patent Document 1. Further, in the production of a non-aqueous electrolyte secondary battery, usually, after the battery assembly is constructed, an activation treatment called conditioning or aging is performed. In the irradiation step, X-rays may be irradiated from the outside of the battery case, so that the battery assembly can be activated at the same time as the irradiation step. Therefore, as compared with, for example, the methods described in Patent Documents 2 and 3, a non-aqueous electrolyte secondary battery can be efficiently manufactured, and productivity can be improved.

In a preferred embodiment, in the irradiation step, X-rays having an energy of 10 keV or more and 15 keV or less are irradiated. In such a manufacturing method, it is not necessary to use a new material for X-ray irradiation. Therefore, it is convenient.

In a preferred embodiment, in the preparation step, at least one of the negative electrode and the non-aqueous electrolyte contains a material capable of emitting characteristic X-rays having an energy of 10 keV or more and 15 keV or less, and the irradiation step. Then, by irradiating X-rays having energy equal to or higher than the X-ray absorption edge of the material, the material is excited, and characteristic X-rays having an energy of 10 keV or more and 15 keV or less are emitted from the material. According to such a manufacturing method, the charge / discharge reactivity of the negative electrode can be adjusted with higher accuracy and / or stably.

It is an exploded view which shows typically the winding electrode body which concerns on 1st Embodiment. It is a perspective view which shows typically the battery assembly which concerns on 1st Embodiment. It is a partially enlarged view which shows typically the neighborhood of the inner wall surface of a battery case.

Hereinafter, preferred embodiments of the manufacturing method disclosed herein will be described. Matters other than those specifically mentioned in the present specification and necessary for carrying out the present invention can be grasped as design matters of those skilled in the art based on the prior art in the art. The manufacturing method disclosed herein can be carried out based on the contents disclosed in the present specification and the common general technical knowledge in the art. In addition, when the numerical value range is described as A to B (where A and B are arbitrary numerical values) in this specification, it means A or more and B or less.

<First Embodiment>
The manufacturing method of the first embodiment is a preparation step of preparing (step S1) an electrode body having a positive electrode and a negative electrode and a non-aqueous electrolyte; (step S2) accommodating the electrode body and the non-aqueous electrolyte in a battery case. Then, the construction step of constructing the battery assembly; (step S3) the irradiation step of irradiating the X-ray toward a predetermined portion (X-ray irradiation portion) of the negative electrode; is included. Such a manufacturing method comprises using a carbon material for the negative electrode in (step S1); using an X-ray permeable battery case in (step S2); and using a battery case in (step S3). It is characterized by irradiating X-rays of a given energy from the outside of the.

Although it is not intended to be particularly limited, here, a method for manufacturing a non-aqueous electrolyte secondary battery provided with a flat wound electrode body will be specifically described as an example.
FIG. 1 is a schematic view of the wound electrode body 10. FIG. 2 is a schematic view of the battery assembly 1. The reference numerals X, Y, and Z in the drawings are directions for convenience of explanation, and mean the thickness direction, the width direction, and the vertical direction of the battery assembly 1, respectively.

(Step S1) Preparation Step In this step, first, the wound electrode body 10 as shown in FIG. 1 is prepared. The wound electrode body 10 has a configuration in which a positive electrode 12 and a negative electrode 14 are arranged to face each other via a separator 16. The wound electrode body 10 can be manufactured, for example, by the following procedure. That is, first, a band-shaped positive electrode 12, a band-shaped negative electrode 14, and a band-shaped separator 16 are prepared.

The positive electrode 12 typically includes a positive electrode current collector 12n and a positive electrode active material layer 12a having a porous structure fixed to both sides of the positive electrode current collector 12n. As the positive electrode current collector 12n, for example, a metal foil such as aluminum or nickel is suitable. The positive electrode active material layer 12a contains a positive electrode active material capable of reversibly storing and releasing charge carriers. Preferable examples of the positive electrode active material include, for example, a lithium transition metal composite oxide. The positive electrode active material layer 12a may contain an arbitrary component (for example, a binder, a conductive material, etc.) other than the positive electrode active material.

The negative electrode 14 typically includes a negative electrode current collector 14n and a negative electrode active material layer 14a having a porous structure fixed to both sides of the negative electrode current collector 14n. The negative electrode current collector 14n is usually composed of a material having lower X-ray transparency than the material of the battery case 20, which will be described later, for example, a material having an energy of the X-ray absorption end of the K shell of about 5 keV or more, for example, 7 keV or more. ing. The negative electrode current collector 14n is composed of, for example, metal species from the 4th period of the periodic table. Specifically, for example, metal foils such as copper (energy at the X-ray absorption edge of the K shell: 9 keV) and nickel (energy at the X-ray absorption edge of the K shell: 8 keV) are suitable. Such an embodiment is particularly preferable when adjusting the charge / discharge reactivity of the negative electrode active material layer 14a located at the outermost peripheral portion of the wound electrode body 10.

The negative electrode active material layer 14a contains a negative electrode active material capable of reversibly storing and releasing charge carriers. The negative electrode active material contains at least a carbon material. Preferable examples of the carbon material include graphite (graphite), non-graphitized carbon (hard carbon), easily graphitized carbon (soft carbon), activated carbon, carbon fiber and the like. The negative electrode active material layer 14a may contain an optional component (for example, a binder, a thickener, etc.) other than the negative electrode active material. Examples of the binder include rubbers such as styrene-butadiene rubber (SBR) and vinyl halide resins such as polyvinylidene fluoride (PVdF). Examples of the thickener include celluloses such as carboxymethyl cellulose (CMC).

The separator 16 insulates the positive electrode 12 and the negative electrode 14. The separator 16 has X-ray transparency. As the separator 16, for example, a porous resin sheet made of a resin such as polyethylene (PE) or polypropylene (PP) is suitable. The separator 16 may be provided with a porous heat-resistant layer containing inorganic compound particles (inorganic filler) on the surface of the resin sheet.

In the production of the wound electrode body 10, next, the band-shaped positive electrode 12 and the band-shaped negative electrode 14 are overlapped with each other via the band-shaped separator 16 and wound in the longitudinal direction orthogonal to the width direction Y. For example, first, two separators 16 are wound around an elliptical winding core for a certain length. Next, the negative electrode 14 is sandwiched between the two separators 16 and wound for a certain length. Next, the positive electrode 12 is sandwiched at a position inside the winding direction of the negative electrode 14 and insulated from the negative electrode 14, and the positive electrode 12 is further wound until the desired number of turns is reached. Then, after winding the separator 16 around the outermost peripheral portion for a certain length, the separator 16 is wound so as not to be unwound.
As a result, the wound electrode body 10 having a flat shape can be manufactured.

The winding electrode body 10 has a pair of winding flat portions and a pair of winding R portions interposed between the pair of winding flat portions in a cross-sectional view. The portion of the wound flat portion where the positive electrode active material layer 12a and the negative electrode active material layer 14a face each other functions as a reaction portion that contributes to charging and discharging of the non-aqueous electrolyte secondary battery.

In the outermost peripheral portion of the wound electrode body 10 in the winding direction, the negative electrode active material layer 14a on one surface is located outside the wound electrode body 10 with respect to the negative electrode current collector 14n. The portion outside the negative electrode current collector 14n does not face the positive electrode active material layer 12a, but faces only the separator 16. The negative electrode active material layer 14a of the wound electrode body 10 has an extra length portion that does not face the positive electrode active material layer 12a at the winding end portion in the winding direction.

In the wound electrode body 10, the length of the negative electrode 14 in the width direction Y is longer than the length of the positive electrode 12 in the width direction Y. Therefore, the negative electrode active material layer 14a has non-opposing portions that do not face the positive electrode active material layer 12a at both ends in the width direction Y.
The positive electrode current collector 12n is exposed at the left end of the wound electrode body 10 in the width direction Y. The negative electrode current collector 14n is exposed at the right end of the wound electrode body 10 in the width direction Y.

In this step, a non-aqueous electrolyte (not shown) is also prepared. The non-aqueous electrolyte is, for example, a non-aqueous electrolyte solution containing a supporting salt in a non-aqueous solvent. Examples of the non-aqueous solvent include aprotic solvents such as carbonates, esters and ethers. Examples of the supporting salt include lithium salts such as _{LiPF 6} and LiBF _4. The non-aqueous electrolyte may further contain various conventionally known additives such as an overcharge additive and a film forming agent.

(Step S2) Construction Step In this step, the battery assembly 1 is constructed. Specifically, first, the battery case 20 is prepared. The battery case 20 shown in FIG. 2 has X-ray transparency at least for a portion to be irradiated with X-rays in the next step S3. The term "X-ray transparency" as used herein means a property of transmitting X-rays of energy irradiated in step S3 (X-rays of energy of 10 to 15 keV in this embodiment). The battery case 20 may be configured to have X-ray transmission as a whole, or may be configured to shield X-rays from a portion other than the portion to be irradiated with X-rays in step S3.

The X-ray transparent portion of the battery case 20 may be made of a material having high X-ray transparency, for example, a material having an energy of approximately 4 keV or less, preferably 2 keV or less at the X-ray absorption end of the K shell. Such materials include lightweight metals such as aluminum (energy at the X-ray absorption edge of the K shell: 1.5 keV) and magnesium (energy at the X-ray absorption edge of the K shell: 1.3 keV); polyphenylene sulfide. , Resins such as polyimide; The thickness of the battery case 20 is usually 0.1 to 5 mm, for example, about 0.5 to 2 mm.

The battery case 20 has a square (rectangular parallelepiped shape) outer shape corresponding to the flat wound electrode body 10. The battery case 20 is composed of a lid 22 forming the upper surface and a case main body 24 forming the bottom surface 24b and the side surfaces 24n and 24w. The case body 24 has a bottom surface 24b facing the lid 22 and a pair of short side surfaces 24n and a pair of long side surfaces 24w as side surfaces continuous from the bottom surface 24b. A positive electrode terminal 12t and a negative electrode terminal 14t for external connection protrude from the lid 22 of the battery case 20.

In this step, next, the wound electrode body 10 prepared in step S1 is housed in the case body 24, and the wound electrode body 10 and the positive electrode terminal 12t and the negative electrode terminal for external connection provided on the lid 22 are provided. 14t and are electrically connected.
Specifically, first, the positive electrode current collector plate 12c is attached to the exposed portion of the positive electrode current collector 12n. Further, the negative electrode current collector plate 14c is attached to the exposed portion of the negative electrode current collector 14n. Next, the positive electrode current collector plate 12c and the positive electrode terminal 12t are electrically connected by welding or the like. Similarly, the negative electrode current collector plate 14c and the negative electrode terminal 14t are electrically connected by welding or the like. As a result, the positive electrode terminal 12t for external connection and the positive electrode of the wound electrode body 10 are electrically connected. Further, the negative electrode terminal 14t for external connection and the negative electrode of the wound electrode body 10 are electrically connected.

One of the pair of winding R portions of the winding electrode body 10 is arranged so as to face the bottom surface 24b of the battery case 20. The pair of winding flat portions (reacting portions) of the winding electrode body 10 are arranged so as to face the pair of long side surfaces 24w of the battery case 20. Both ends of the wound electrode body 10 in the width direction Y are arranged so as to face the pair of short side surfaces 24n of the battery case 20. There is a slight gap between the wound electrode body 10 and the inner wall surface of the battery case 20.

In this step, next, the non-aqueous electrolyte prepared in step S1 is housed inside the battery case 20. When a non-aqueous electrolytic solution is used, for example, after the lid 22 and the case body 24 are welded to seal the battery case 20, the liquid injection port (not shown) provided on the lid 22 is used. Inject a non-aqueous electrolyte solution. The injected non-aqueous electrolytic solution is impregnated into the positive electrode active material layer 12a, the negative electrode active material layer 14a, and the separator 16 having a porous structure, respectively.
This makes it possible to construct a battery assembly.

(Step S3) Irradiation Step In this step, the X-ray irradiation site is irradiated with X-rays. Specifically, first, an X-ray irradiation device is prepared. The X-ray irradiation device may be any device capable of irradiating energy of 10 to 15 keV. The X-ray irradiation device may be one that irradiates continuous X-rays, or may be one that can irradiate pulsed X-rays.

Then, from the outside of the battery case 20 of the battery assembly 1, the X-ray irradiation portion of the negative electrode 14 is irradiated with X-rays from the X-ray irradiation device.
In the present embodiment, the energy of the X-ray to be irradiated is 10 to 15 keV. As described in Patent Document 3, the range of this energy is equivalent to the energy of the X-ray absorption edge of the K shell of carbon (C). Irradiation with X-rays of the energy has the effect of reducing the charge / discharge reactivity of the carbon material at the X-ray irradiation site. This mechanism is not clear, but one reason is that irradiation with X-rays in the energy range may cause some changes on the surface of the carbon material. For example, it is conceivable that the solvent and supporting salt contained in the non-aqueous electrolyte are decomposed on the surface of the carbon material to form a highly resistant film on the surface of the carbon material.

From the viewpoint of shortening the irradiation time, the energy of the X-ray to be irradiated is preferably 11 to 14 keV. When it is desired to completely inactivate the carbon material existing in the X-ray irradiation site, the energy of the X-ray to be irradiated may be 12 ± 1 keV.

The intensity (luminance) of X-rays and the irradiation time of X-rays are not particularly limited because they depend on the energy of the X-rays to be irradiated. The intensity of X-rays can be, for example, 1 × 10 ⁸ to 1 × 10 ¹³ photons / s. The X-ray irradiation time is, for example, 50 to 500 min. Can be. In general, the stronger the X-ray intensity and / or the longer the X-ray irradiation time, the more the charge / discharge reactivity of the carbon material existing in the X-ray irradiation site is desired to be significantly reduced.

Irradiation of X-rays may be performed continuously using continuous X-rays or intermittently using pulsed X-rays. When it is desired to completely inactivate the carbon material existing in the X-ray irradiation site, continuous X-rays may be used. When it is desired to gently reduce the charge / discharge reactivity of the carbon material existing in the X-ray irradiation site, pulse X-rays may be used. When pulse X-rays are used, the pulse width may be, for example, 10 to 100 fs. As a result, X-rays can reach a depth of approximately 5 to 100 nm from the surface of the negative electrode active material layer 14a on the side irradiated with pulsed X-rays. Therefore, the charge / discharge reactivity of the carbon material can be selectively adjusted with respect to the outermost surface of the negative electrode active material layer 14a of the X-ray irradiation site.

The X-ray irradiation site may be set at a site where the charge / discharge reactivity of the negative electrode active material is desired to be reduced or lost (deactivated). In other words, the X-ray irradiation site can be appropriately determined according to the configuration of the wound electrode body 10, the purpose of reducing the charge / discharge reactivity, and the like.
In an example of X-ray irradiation, the entire pair of long side surfaces 24w of the battery case 20 is irradiated with X-rays. As a result, the charge / discharge reactivity is selectively selected for the extra length portion at the end of winding of the negative electrode 14 in the winding direction, that is, the portion of the negative electrode active material layer 14a that does not face the positive electrode active material layer 12a. Decrease.

FIG. 3 is a partially enlarged view schematically showing the vicinity of the inner wall surface of the battery case 20 when X-rays are irradiated from the side of the long side surface 24w. As shown by an arrow in FIG. 3, X-rays (primary X-rays) emitted from the X-ray irradiation device toward the battery case 20 pass through the X-ray transparent battery case 20 and are wound electrode bodies. It reaches the outermost peripheral portion of 10. The X-rays that reach the outermost peripheral portion of the wound electrode body 10 pass through the X-ray transparent separator 16 and are located outside the negative electrode current collector 14n (left side in FIG. 3). Reach the extra length of. The X-rays that reach the extra length selectively reduce the charge / discharge reactivity of the carbon material as the negative electrode active material. As a result, precipitation of charge carriers (for example, Li precipitation) can be suppressed in the extra length portion of the negative electrode active material layer 14a, and the durability of the non-aqueous electrolyte secondary battery can be improved.

When the negative electrode current collector 14n does not have X-ray transmission, the X-rays emitted from the X-ray irradiator are shielded by the negative electrode current collector 14n. Therefore, X-rays do not reach the negative electrode active material layer 14a and the positive electrode active material layer 12a located inside the negative electrode current collector 14n of the wound electrode body 10 (on the right side in FIG. 3). Therefore, the charge / discharge reactivity does not decrease inside the negative electrode current collector 14n of the wound electrode body 10. As described above, in the present embodiment, only the charge / discharge reactivity of the extra length portion located outside the negative electrode current collector 14n of the wound electrode body 10 can be suitably reduced.

In another example of X-ray irradiation, the entire pair of short side surfaces 24n of the battery case 20 is irradiated with X-rays. As a result, charge / discharge reactivity is selected for the non-opposing portions at both ends of the negative electrode 14 in the width direction Y, that is, the portion of the negative electrode active material layer 14a that does not face the positive electrode active material layer 12a in the width direction Y. Decrease. As a result, it is possible to suppress performance deterioration (for example, increase in self-discharge amount, increase in resistance, etc.) due to deviation of the charge / discharge reaction, and it is possible to improve the durability of the non-aqueous electrolyte secondary battery. ..

That is, since both end portions of the positive electrode active material layer 12a in the width direction Y are close to the non-opposing portions of the negative electrode 14, the amount of charge carriers released during charging tends to be larger than that of the central portion in the width direction Y. In other words, it tends to be locally high potential. By reducing the charge / discharge reactivity of the non-opposing portion of the negative electrode 14, it is possible to prevent the positive electrode active material layer 12a from becoming locally high potential. As a result, the charge / discharge reaction can be uniformly generated in the width direction Y of the electrode body.

Further, in this step, a process as performed on the battery assembly by the conventional manufacturing method, for example, an activation process (conditioning or aging) can be performed at the same time as the irradiation with X-rays. By performing a plurality of treatments on the battery assembly in parallel, a non-aqueous electrolyte secondary battery can be efficiently manufactured, and productivity can be improved.

As described above, according to the manufacturing method disclosed herein, the charge / discharge reactivity of the negative electrode can be adjusted with high reproducibility and high accuracy as compared with the conventional case. In addition, a non-aqueous electrolyte secondary battery can be efficiently manufactured, and productivity can be improved.
The non-aqueous electrolyte secondary battery produced in this manner is superior in durability (for example, cycle characteristics) as compared with the conventional product. For example, the amount of self-discharge is reduced, and a high battery capacity can be maintained even after repeated charging and discharging. Therefore, taking advantage of such properties, the non-aqueous electrolyte secondary battery can be suitably used as a power source (drive power source) for a motor of, for example, a plug-in hybrid vehicle, a hybrid vehicle, an electric vehicle, or the like.

<Second Embodiment>
The manufacturing method of the second embodiment is the steps S11 to S13 corresponding to the above-mentioned steps S1 to S3 of the first embodiment, that is, (step S11) preparation step; (step S12) construction step; (step S13) irradiation step. Includes; Such a manufacturing method uses a carbon material as the negative electrode active material in the following item: (step S11), and at least one of the negative electrode and the non-aqueous electrolyte contains a characteristic X-ray emitting material; (Step S13), it is characterized by irradiating X-rays of a predetermined energy from the outside of the battery case; Since the matters other than those mentioned below are the same as those in the first embodiment described above, detailed description thereof will be omitted.

In step S11, at least one of the negative electrode and the non-aqueous electrolyte contains the characteristic X-ray emitting material. The characteristic X-ray emitting material can emit characteristic X-rays (secondary X-rays) having an energy of 10 to 15 keV by irradiating X-rays (primary X-rays) having an energy equal to or higher than the X-ray absorbing end. Material. The energy of the characteristic X-rays emitted from the characteristic X-ray emitting material is determined by the elemental composition. In other words, the energy of characteristic X-rays is a value specific to the type of element. The energy of characteristic X-rays can be grasped from conventionally known documents, various data books, and the like.

Table 1 shows "Guide for using the XAFS experimental station" of the Institute of Materials Structure Science, July 2001, Internet <http://pfxafs.kek.jp/wp-content/uploads/2012/12/handbook1.pdf# search =% 27PF +% E9% 87% 8E% E6% 9D% 91 +% E6% 89% 8B% E5% BC% 95% E3% 81% 8D% 27> Shown.
As shown in Table 1, the characteristic X-ray emitting material is theoretically an element capable of emitting characteristic X-rays having an energy of 10 to 15 keV, that is, the following elements: gallium (Ga) to yttrium (Y); rhenium (Re). ) To uranium (U); any material having at least one of them may be used.

Specific examples of the characteristic X-ray emitting material that can be contained in the negative electrode active material layer 14a of the negative electrode 14 include a negative electrode active material containing Ge, As, and Pb. The characteristic X-ray emitting material may be added to the entire negative electrode active material layer 14a, or may be added only to the X-ray irradiation site. Characteristics The proportion of the negative electrode material additionally contained as the X-ray emitting material is not particularly limited, but when the total negative electrode active material is 100% by mass, it is generally less than 50% by mass, typically 10% by mass or less. For example, it may be 5% by mass or less.

Specific examples of the characteristic X-ray emitting material contained in the non-aqueous electrolyte include lithium hexafluoride arsenate (LiAsF ₆ ) as a supporting salt, Ge, As, Br, Sr, Y, Pb, and Bi. Additives such as Li _1.5 Al _0.5 Ge _1.5 (PO ₄ ) _{3 and the} like can be mentioned. The supporting salt as the characteristic X-ray emitting material can be used in place of or in combination _{with the above-mentioned LiPF 6} and LiBF _4. The concentration of the supporting salt as the characteristic X-ray emitting material is not particularly limited, but may be approximately 0.7 to 2.0 mol / L, for example 1.0 to 1.3 mol / L. Characteristics as an Additive The X-ray emitting material can be approximately 0.1 to 10% by mass, for example 1 to 5% by mass, when the total amount of the non-aqueous electrolyte is 100% by mass.

When the wound electrode body 10 and the non-aqueous electrolyte are housed in the battery case 20 in step S12, the positive electrode active material layer 12a, the negative electrode active material layer 14a, and the separator 16 are each impregnated with the non-aqueous electrolyte. That is, when the characteristic X-ray emitting material is contained in the non-aqueous electrolyte in step S11, a part of the characteristic X-ray emitting material is contained in the negative electrode active material layer 14a.

In step S13, X-rays having energy equal to or higher than the X-ray absorption edge of the characteristic X-ray emitting material are irradiated. Generally, in an X-ray irradiation device, the higher the energy of the X-ray to be irradiated, the larger the X-ray irradiation unit becomes. Therefore, the energy of the X-ray to be irradiated is not particularly limited, but may be, for example, 15 to 20 keV.

The X-rays (primary X-rays) emitted from the X-ray irradiation device pass through the battery case 20 and the separator 16 and reach the extra length portion of the negative electrode active material layer 14a, as in the first embodiment. To do. The primary X-rays that reach the extra length have more energy than the X-ray absorption edge of the characteristic X-ray emitting material. Therefore, the characteristic X-ray emitting material existing in the extra length portion is excited by the primary X-ray, and the characteristic X-ray (secondary X-ray) is emitted from the characteristic X-ray emitting material. Secondary X-rays have an energy of 10 to 15 keV. Characteristic By emitting secondary X-rays in the energy range from the X-ray emitting material, the effect of selectively reducing the charge / discharge reactivity of the carbon material at the X-ray irradiation site is the same as in the first embodiment described above. There is.

Although the present invention has been described in detail above, the above-described embodiments and examples are merely examples, and the inventions disclosed herein include various modifications and modifications of the above-mentioned specific examples.

In the above embodiment, the negative electrode 14 includes, but is not limited to, a negative electrode current collector 14n and a negative electrode active material layer 14a fixed to both sides of the negative electrode current collector 14n, respectively. The negative electrode may be, for example, a carbon sheet, or the negative electrode active material layer 14a may be self-supporting and may be formed into a sheet shape. In this case, it is preferable to use pulsed X-rays in the irradiation step of step S3. As a result, it is possible to suppress a decrease in the charge / discharge reactivity of the reaction portion that contributes to charge / discharge, and selectively reduce the charge / discharge reactivity only in the extra length portion of the negative electrode active material layer.

In the above embodiment, the wound electrode body 10 is prepared in step S1, but the present invention is not limited to this. The electrode body may be a laminated electrode body in which a rectangular positive electrode and a rectangular negative electrode are superposed with each other via a rectangular separator.

In the above embodiment, a liquid non-aqueous electrolyte (non-aqueous electrolyte) is prepared in step S1, but the present invention is not limited to this. The non-aqueous electrolyte may be, for example, a so-called solid electrolyte in which a polymer is added to a non-aqueous electrolyte solution to form a gel. In that case, instead of the separator 16, a solid electrolyte may be interposed between the positive electrode 12 and the negative electrode 14 to insulate the positive electrode 12 and the negative electrode 14.

1 Battery assembly 10 Winding electrode body 12 Positive electrode 14 Negative electrode 20 Battery case

Claims (2)

A preparation step of preparing an electrode body in which a positive electrode containing a positive electrode active material and a negative electrode containing a carbon material as a negative electrode active material are arranged to face each other in an insulated state, and a non-aqueous electrolyte;
A construction step of accommodating the electrode body and the non-aqueous electrolyte inside a battery case having X-ray transparency to construct a battery assembly; and
An irradiation step of irradiating a predetermined portion of the negative electrode with X-rays from the outside of the battery case to reduce the charge / discharge reactivity of the carbon material at the predetermined portion;
Including ,
In the preparation step, at least one of the negative electrode and the non-aqueous electrolyte contains a material capable of emitting characteristic X-rays having an energy of 10 keV or more and 15 keV or less.
In the irradiation step, the material is excited by irradiating X-rays having an energy equal to or higher than the X-ray absorption edge of the material, and characteristic X-rays having an energy of 10 keV or more and 15 keV or less are emitted from the material. A method for manufacturing a water electrolyte secondary battery. The manufacturing method according to claim 1, wherein in the irradiation step, X-rays having an energy of 10 keV or more and 15 keV or less are irradiated.

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