JP5252691B2 - Cylindrical non-aqueous electrolyte primary battery and manufacturing method thereof - Google Patents

Description

  The present invention relates to a cylindrical non-aqueous electrolyte primary battery excellent in heavy load pulse discharge characteristics and heavy load continuous discharge characteristics, and a method for producing the same.

  A cylindrical non-aqueous electrolyte primary battery may be required to be able to take out a large current instantaneously, that is, to have excellent heavy load pulse discharge characteristics, as in a camera application. In the current cylindrical non-aqueous electrolyte primary battery, for example, by using an electrode group having a winding structure in which a positive electrode and a negative electrode are wound in a spiral shape via a separator, a large electrode area is secured, It corresponds to the request of.

  In addition, in the cylindrical non-aqueous electrolyte primary battery, in addition to using a wound electrode group, a technique for forming a negative electrode used for the electrode group by laminating a metal lithium foil and an aluminum foil is also available. It has been proposed (for example, Patent Document 1). According to the technique described in Patent Document 1, in the battery, the metal lithium foil and the aluminum foil of the negative electrode are electrochemically alloyed to form a lithium-aluminum alloy, which is pulverized. Can be further increased, and the heavy load pulse discharge characteristics of the battery can be further enhanced.

JP 2007-250414 A

  However, the use of cylindrical non-aqueous electrolyte primary batteries has also been diversified recently. For example, not only when a large instantaneous current is required, such as a power supply for an alarm device, In some cases, it is required to be excellent in characteristics that can be discharged smoothly, that is, in heavy load continuous discharge characteristics. As described above, the battery described in Patent Document 1 has excellent heavy load pulse discharge characteristics, but there is still room for improvement in heavy load continuous discharge characteristics.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a cylindrical non-aqueous electrolyte primary battery excellent in heavy load pulse discharge characteristics and heavy load continuous discharge characteristics, and a manufacturing method thereof. It is in.

  The cylindrical non-aqueous electrolyte primary battery of the present invention that has achieved the above object has a winding structure in which a positive electrode containing manganese dioxide or graphite fluoride and a negative electrode are wound in a spiral shape via a separator. The negative electrode has a metallic lithium-containing layer and a current collector, and is 20 to 75% of the width of the metallic lithium-containing layer. The lithium-aluminum alloy is formed on the surface opposite to the current collector.

  In addition, the method for producing a cylindrical non-aqueous electrolyte primary battery according to the present invention includes an electrode having a winding structure in which a positive electrode containing manganese dioxide or graphite fluoride and a negative electrode are wound in a spiral shape via a separator. In manufacturing a cylindrical non-aqueous electrolyte primary battery having a group, a current collector is disposed on one side of a metal lithium foil or lithium alloy foil, and the surface opposite to the metal lithium foil or lithium alloy foil current collector In addition, a negative electrode in which an aluminum foil having a width of 20 to 75% of the width of the metal lithium foil or the lithium alloy foil is disposed is used.

  In a battery using a wound electrode body having a negative electrode formed by laminating metal lithium foil or lithium alloy foil and aluminum foil, as described above, a lithium-aluminum alloy is formed on the negative electrode surface in the battery. Since this is pulverized and the surface area of the negative electrode is increased, the heavy load pulse discharge characteristics are improved.

  However, in the battery described above, lithium cannot be directly taken out from the lithium-aluminum alloy related to the negative electrode into the non-aqueous electrolyte, so that the supply of lithium from the negative electrode catches up even if heavy load discharge is continuously performed. For these reasons, the present inventors have found that it is difficult to perform continuous heavy-load discharge of the battery.

  Therefore, in the cylindrical non-aqueous electrolyte primary battery of the present invention, the width of the aluminum foil for constituting the negative electrode is reduced to 20 to 75% of the width of the metal lithium foil or lithium alloy foil, and the metal lithium according to the negative electrode A lithium-aluminum alloy was formed only in a portion of 20 to 75% of the width of the metal lithium-containing layer derived from the foil or lithium alloy foil. As a result, in the metallic lithium-containing layer of the negative electrode, a region where lithium can be directly taken out into the non-aqueous electrolyte is secured, so that lithium can be supplied quickly from this region, and the heavy load continuous discharge characteristics of the battery are also improved. .

  In addition, the term “heavy load pulse discharge” in the present specification means that an instantaneous discharge with a length of about 0.01 seconds to 10 seconds is performed at a current of 300 to 3000 mA, “Heavy load continuous discharge” means continuous discharge at a current of 100 to 1000 mA for about 1 minute to 15 hours.

  ADVANTAGE OF THE INVENTION According to this invention, the cylindrical nonaqueous electrolyte primary battery excellent in the heavy load pulse discharge characteristic and the heavy load continuous discharge characteristic can be provided.

  FIG. 1 is a longitudinal side view showing an embodiment of a cylindrical non-aqueous electrolyte primary battery of the present invention. In FIG. 1, a cylindrical non-aqueous electrolyte primary battery 1 includes a bottomed cylindrical outer can 2 having an upper opening, a sheet-like positive electrode 4 and a sheet-like negative electrode 5 loaded in the outer can 2. Electrode group 3 having an electrode structure formed by winding through a separator 6, a non-aqueous electrolyte (hereinafter simply referred to as “electrolyte”), and a sealing structure that seals the upper opening of the outer can 2. ing. In other words, the nonaqueous electrolyte battery 1 of FIG. 1 has a sheet-like positive electrode 4 and a sheet-like negative electrode 5 in a space surrounded by an outer can 2 and a sealing structure that seals the upper opening of the outer can 2. And a power generation element such as an electrode group 3 having a winding structure and an electrolyte solution. The outer can 2 is made of iron, stainless steel, or the like.

  The sealing structure is attached to the cover plate 7 fixed to the inner peripheral edge of the upper opening of the outer can 2 and the opening formed in the center of the cover plate 7 through an insulating packing 8 made of polypropylene or the like. Terminal body 9 and insulating plate 10 disposed under cover plate 7. The insulating plate 10 is formed in a round plate shape having an annular side wall 12 standing on the periphery of the disk-shaped base portion 11 and opening upward, and a gas passage 13 is opened at the center of the base portion 11. Yes. The cover plate 7 is fixed to the inner peripheral edge of the upper opening of the outer can 2 by laser welding or a crimp seal through packing while being received by the upper end of the side wall 12. As a countermeasure when the battery internal pressure suddenly increases, a thin portion (vent) can be provided on the lid 7 or the can bottom 2a of the outer can 2. The positive electrode 4 and the lower surface of the terminal body 9 are connected by a positive electrode lead body 15. Further, the negative electrode lead body 16 attached to the negative electrode 5 is welded to the upper inner surface of the outer can 2. Reference numeral 14 denotes an insulating plate disposed inside the can bottom 2 a of the outer can 2.

  FIG. 2 shows an enlarged cross-sectional view of an example of a wound structure electrode group used in the battery of the present invention. The negative electrode 5 shown in FIG. 2 has a metal lithium foil or lithium alloy foil 51, an aluminum foil 52, and a current collector 53. In the positive electrode 4, positive electrode mixture sheets 41 and 41 are arranged on both surfaces of the current collector 42.

  In the negative electrode 5 shown in FIG. 2, an aluminum foil 52 is disposed on one surface of a metal lithium foil or lithium alloy foil 51, and the surface opposite to the surface on which the aluminum foil 52 of the metal lithium foil or lithium alloy foil 51 is disposed. The current collector 53 is disposed in the case. And the aluminum foil 52 is the width | variety (the length of the vertical direction in FIG. 2, ie, the length of the direction parallel to the winding axis direction in the electrode group of a winding structure. The winding structure described hereafter. The same applies to the “width” of each component of the electrode group.) Is smaller than the metal lithium foil or the lithium alloy foil 51.

  When a battery is configured using the electrode group configured as described above, in the negative electrode related to the electrode group, aluminum related to the aluminum foil in the coexistence of the non-aqueous electrolyte is lithium related to the metal lithium foil or lithium alloy foil. Reacts to form a lithium-aluminum alloy. Therefore, the “metal lithium-containing layer” in the negative electrode according to the battery of the present invention is formed by the reaction between the metal lithium foil or the lithium alloy foil and the aluminum foil disposed on the surface thereof.

  As shown in FIG. 2, the aluminum foil 52 is smaller than the metal lithium foil or the lithium alloy foil 51, so that the lithium is only in the portion of the surface of the metal lithium foil or the lithium alloy foil 51 where the aluminum foil 52 exists. An aluminum alloy is formed and the other part remains in a state where lithium can be taken directly into the non-aqueous electrolyte. That is, the “metal lithium-containing layer” in the negative electrode according to the present invention has a lithium-aluminum alloy formed on only a part of its surface, and the surface of the other part can directly extract lithium into the non-aqueous electrolyte. State. By adopting such a configuration, it is possible to improve the heavy load continuous discharge characteristics while enhancing the heavy load pulse discharge characteristics of the battery.

  Specifically, the width of the aluminum foil is 20% or more, preferably 40% or more, of the width of the metal lithium foil or lithium alloy foil from the viewpoint of enhancing the heavy load pulse characteristics of the battery. That is, in the battery of the present invention, in the metallic lithium-containing layer according to the negative electrode, the portion where the lithium-aluminum alloy is formed on the surface is a portion of 20% or more of the width of the metallic lithium-containing layer, and 40% The above part is preferable.

  And from a viewpoint of improving the heavy load continuous discharge characteristic of a battery, the width | variety of aluminum foil is 75% or less of the width | variety of metal lithium foil or lithium alloy foil, and it is preferable that it is 50% or less. That is, in the battery of the present invention, in the metallic lithium-containing layer according to the negative electrode, the portion where the lithium-aluminum alloy is formed on the surface is a portion of 75% or less of the width of the lithium alloy layer, and 50% or less. It is preferable that this part.

  In the lithium metal-containing layer of the negative electrode according to the battery of the present invention, the width of the region in which the lithium-aluminum alloy is formed can be visually discerned by the difference in color because the color of the surface is different from other parts. is there.

  Moreover, in the electrode group of the winding structure used for the battery of this invention, as shown in FIG. 2, the center part of the width direction of the aluminum foil 52 which concerns on the negative electrode 5 is a winding axis | shaft in the electrode group of a winding structure. It is preferable that it is located on the battery bottom (can bottom) side with respect to the central portion in the direction, and the width of the separator 6 is larger than the width of the positive electrode 4. That is, in the battery of the present invention, the central portion in the width direction of the portion where the lithium-aluminum alloy is formed in the negative electrode is positioned closer to the battery bottom than the central portion in the winding axis direction in the electrode group of the winding structure. And the width of the separator is preferably larger than the width of the positive electrode.

  As described above, the aluminum related to the aluminum foil 52 forms a fine powder by forming a lithium-aluminum alloy with lithium related to the metal lithium foil or the lithium alloy foil 51. However, when the aluminum falls off the negative electrode 5 and contacts the positive electrode 4, a short circuit occurs. Will occur. Therefore, the width of the separator is made larger than the width of the positive electrode, for example, the portion protruding from the positive electrode of the separator is bent toward the winding center side of the electrode group of the winding structure, and the upper side of the battery of the electrode group of the winding structure is If the end face of the positive electrode is covered with a separator on the surface or the battery bottom surface, even if the lithium-aluminum alloy powder falls off from the negative electrode, the occurrence of a short circuit due to contact with the positive electrode can be suppressed.

  However, as shown in FIG. 1, the end surface of the positive electrode 4 can be easily covered by bending the end portion of the separator 6 on the surface of the battery bottom side of the electrode group having the winding structure, while the electrode group having the winding structure. On the upper surface of the battery, since the positive electrode 4 and the positive electrode lead body 15 are connected as shown in FIG. 1, it is difficult to cover the end surface of the positive electrode 4 by bending the end portion of the separator 6. is there. Therefore, as shown in FIG. 2, the aluminum foil 52 is arranged on the lower side in the drawing, that is, on the battery bottom side, and the lithium-aluminum alloy powder dropped from the negative electrode is on the battery upper side of the wound electrode group. It is preferable to adopt a configuration that is difficult to go out of the electrode group from the outside, and by adopting such a configuration, occurrence of a short circuit can be satisfactorily suppressed.

  Therefore, in order to better suppress the occurrence of a short circuit due to the lithium-aluminum alloy powder falling off from the negative electrode, in the electrode body having a wound structure used for the battery, the central portion in the width direction of the aluminum foil according to the negative electrode However, in addition to disposing the aluminum foil so as to be located on the battery bottom side with respect to the central portion in the winding axis direction in the electrode group having the winding structure, as shown in FIG. It is preferable that the portion of the separator that protrudes from the positive electrode on the bottom side surface is bent toward the winding center of the electrode group having a winding structure. That is, in the electrode body having a winding structure of the battery, the center portion in the width direction of the location where the lithium-aluminum alloy related to the negative electrode is formed is closer to the battery bottom than the center portion in the winding axis direction in the electrode group having the winding structure 1, the part protruding from the positive electrode of the separator on the surface of the battery bottom side of the electrode group having the winding structure is the winding center of the electrode group having the winding structure, as shown in FIG. 1. It is preferable to bend toward the side.

  In forming a battery in which a portion protruding from the positive electrode of the separator on the battery bottom surface of the electrode group having a winding structure is bent toward the winding center side of the electrode group, the portion of the separator is bent. After that, the method of inserting the electrode group into the outer can may be adopted, and after the portion of the separator is bent, the bent portion of the separator is pressed at a temperature at which the separator is melted and bent. A method of inserting the wound electrode group into the outer can after the fused separator portions are fused may be employed.

  In the negative electrode according to the present invention, as described above, an aluminum foil is disposed on a part of one surface of a metal lithium foil or a lithium alloy foil, and the side opposite to the surface on the aluminum foil side of the metal lithium foil or lithium alloy foil A negative electrode having a current collector disposed on the surface is used.

  As the lithium alloy foil, a foil made of a lithium alloy other than a lithium-aluminum alloy, for example, a lithium alloy such as a lithium-magnesium alloy, a lithium-tin alloy, a lithium-zinc alloy, a lithium-antimony alloy, or a lithium-silicon alloy. Can be used. In addition, in the lithium alloy which comprises lithium alloy foil, it is preferable that lithium content is 90 mass% or more.

  The thickness of the metal lithium foil or lithium alloy foil is preferably 0.05 to 0.4 mm, for example.

  The thickness of the aluminum foil used for the negative electrode is, for example, a sufficient amount of lithium-aluminum alloy is formed, and the effect of forming this is ensured better. From the viewpoint of suppressing the occurrence of winding failure due to cutting of the aluminum foil during winding, the thickness is preferably 3 μm or more. However, if the aluminum foil is too thick, the amount of aluminum not involved in the discharge increases and the discharge capacity of the battery may be reduced. Therefore, the thickness of the aluminum foil is preferably 15 μm or less.

  Examples of the material for the negative electrode current collector include copper, nickel, iron, and stainless steel. Since the internal volume of the outer can decreases by the thickness of the negative electrode current collector, the thickness dimension of the negative electrode current collector is preferably as small as possible, specifically, for example, 0.1 mm or less. Recommended. That is, if the negative electrode current collector is too thick, the thickness of the metal lithium-containing layer (metal lithium foil or lithium alloy foil) containing lithium that acts as the negative electrode active material has to be reduced, and the battery capacity is reduced. There is a risk of inviting. Moreover, since it will be easy to tear when a negative electrode collector is too thin, it is desirable that the thickness of a negative electrode collector be 0.005 mm or more. The width of the negative electrode current collector is preferably the same as or wider than the width of the metal lithium foil or lithium alloy foil (that is, the metal lithium-containing layer), and the area of the metal lithium disposed on one side is preferable. It is preferably 100 to 130% of the area of the foil or lithium alloy foil. By setting the area of the negative electrode current collector as described above, the width of the negative electrode current collector is the same as or wider than the width of the metal lithium foil or lithium alloy foil, and the length becomes longer. It is possible to prevent the metal lithium foil or the lithium alloy foil from being cut and the electrical connection from being cut.

  As the positive electrode according to the present invention, for example, as shown in FIG. 2, a sheet-like positive electrode having a configuration in which two positive electrode mixture sheets are laminated via a current collector can be used. In the sheet-like positive electrode having such a structure, for example, the current collector is overlapped by three mm so that the current collector is located a few mm inside of the two positive electrode mixture sheets, and the lengthwise direction that becomes the winding start end portion It can be produced by pressing a portion of 3 to 10 mm from the end. From the viewpoint of work, it is preferable that the two positive electrode mixture sheets and the positive electrode current collector are integrated prior to the production of the electrode group having a wound structure. The mixture sheet and the current collector may be integrated at the time of winding the electrode group having a wound structure, and there is no particular problem in terms of characteristics even by such a manufacturing method.

  As the positive electrode mixture sheet, for example, a positive electrode mixture (slurry) obtained by blending a positive electrode active material with a conductive additive or a binder and adding water or the like as necessary is rolled using a roll or the like. Then, a pre-sheet can be formed, and a product obtained by drying and pulverizing the sheet can be roll-rolled again to form a sheet shape. As the positive electrode active material, manganese dioxide or graphite fluoride is used, and only one of them may be used or both may be used in combination. Examples of the conductive assistant include graphite, carbon black (Ketjen black, etc.) and acetylene black. These may be used alone or in combination of two or more. As the binder, polytetrafluoroethylene (PTFE), rubber binder, or the like can be used. In the case of PTFE, a dispersion type or a powder type may be used, but a dispersion type is particularly preferable.

  In the positive electrode mixture sheet, for example, the content of the positive electrode active material is 92 to 97% by mass, the content of the conductive additive is 2 to 4% by mass, and the content of the binder is 1 to 4% by mass. preferable.

  It is preferable that the positive electrode mixture sheet has a thickness corresponding to 4 to 9% of the inner diameter of the battery outer can per sheet. By providing a positive electrode having a thick positive electrode mixture sheet in this manner, the occupied volume ratio of the positive electrode in the battery is increased to reduce unnecessary gaps in the battery, and the filling amount of the positive electrode active material is increased to increase the battery capacity. Capacitance can be achieved. The specific thickness of each positive electrode mixture sheet varies depending on the size of the battery (the size of the outer diameter of the outer can), but is usually 0.5 to 1.0 mm.

Moreover, it is preferable that the density of a positive mix sheet is 2.1-2.8 g / cm < ³ >, for example. In addition, the density of the positive mix sheet as used in this specification is a value calculated | required by the volume and mass of the positive mix sheet of a dry state.

In addition, carbon black (especially Ketjen black) whose BET specific surface area is 400-2000 m < ² > / g is used for a conductive support agent, Content of the said conductive support agent in a positive mix sheet is 2.0-4.0 mass. %, And the density of the positive electrode mixture sheet is more preferably 2.2 to 2.7 g / cm ³ , which can also enhance the discharge characteristics at the middle load of the battery. In addition, the BET specific surface area of the conductive assistant referred to in this specification is a surface area measured and calculated using the BET formula which is a theoretical formula of multimolecular adsorption. is there. Moreover, the specific surface area measuring apparatus by the nitrogen adsorption method ("Macsorb HM model-1201" by Mounttech) was used for the measurement of the BET specific surface area of carbon black in the Example mentioned later.

  Examples of the current collector used for the positive electrode include those made of stainless steel such as SUS316, SUS430, and SUS444, and the forms thereof include plain weave metal mesh, expanded metal, lath net, punching metal, and foil (plate). Etc. can be exemplified. The thickness of the current collector is preferably, for example, 0.1 to 0.4 mm.

  Note that it is desirable to apply a paste-like conductive material to the surface of the positive electrode current collector. When a positive electrode current collector having a three-dimensional structure is used, as in the case of using an essentially flat material such as a metal foil or a punching metal, the current collecting effect is remarkable by applying a conductive material. Improvement is observed. This is because the route through the conductive material filled in the mesh is effectively used as well as the route in which the metal part of the mesh current collector is in direct contact with the positive electrode mixture sheet. It is estimated to be.

  As the conductive material, for example, silver paste or carbon paste can be used. In particular, the carbon paste is suitable for reducing the manufacturing cost of the non-aqueous electrolyte battery because the material cost is lower than that of the silver paste and the contact effect is almost the same as that of the silver paste. As the binder for the conductive material, it is preferable to use a heat resistant material such as water glass or an imide binder. This is because the drying treatment is performed at a high temperature exceeding 200 ° C. when moisture in the positive electrode mixture sheet is removed.

  There is no restriction | limiting in particular as a separator which concerns on the battery of this invention, The separator made from a microporous film and the separator made from a nonwoven fabric employ | adopted as a conventionally well-known nonaqueous electrolyte primary battery can be used.

  As used herein, the term “microporous film” refers to a film-like body composed of a resin (including so-called sheet-like bodies and plate-like bodies) that includes a large number of minute pores, Ions can pass through the film. For example, fine particles (inorganic fine particles) are blended into a resin and molded into a film-like body, which is stretched uniaxially or biaxially to generate cracks in the vicinity of the fine particles to form pores Etc. can be used. Examples of the resin constituting the microporous film include polyolefins such as polyethylene (PE) and polypropylene (PP); polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); polyphenylene sulfide (PPS); Can be mentioned. Examples of such commercially available microporous films include “Hypore” (trade name) manufactured by Asahi Kasei Corporation, “Setilla” (trade name) manufactured by Tonen Chemical Co., Ltd., and the like.

  In addition, as a nonwoven fabric related to the separator, for example, polyolefin such as polyethylene (PE) and polypropylene (PP); polyester such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); polyphenylene sulfide (PPS); Those produced by various known production methods can be used.

  The thickness of the separator is preferably 20 to 100 μm, for example.

  In the battery of the present invention, a separator having a microporous film and a nonwoven fabric as constituent elements is preferably used. In the case of a separator having a structure in which a microporous film and a nonwoven fabric are laminated and these are laminated, in the electrode group having a wound structure, the breakage of the separator by the positive electrode active material on the positive electrode surface is suppressed, and a short circuit is prevented. Generation | occurrence | production can be prevented and also the fall of the battery characteristic resulting from omission of the micronized lithium-aluminum alloy in the negative electrode surface can also be prevented.

  That is, if a microporous film and a non-woven fabric are used in combination, even if a microporous film alone causes a crack or the like and a short circuit occurs, a crack or the like does not easily occur and the penetration strength is high. Occurrence of a short circuit can be prevented by the presence of the nonwoven fabric.

  In addition, the finely divided lithium-aluminum alloy on the negative electrode surface may fall off the negative electrode, for example, when an external impact is applied to the battery. Such a dropped lithium-aluminum alloy passes through the separator. If it moves to the positive electrode, it reacts with the positive electrode active material, causing a voltage failure in which the voltage of the battery decreases. If a separator having the microporous film and the nonwoven fabric as constituent elements is used, the microporous film prevents the lithium-aluminum alloy that has fallen off from the negative electrode from moving to the positive electrode, thereby preventing the occurrence of the voltage failure. It is possible to suppress the deterioration of battery characteristics.

  In addition, when the microporous film which concerns on a separator has a crack etc., the movement inhibitory effect to the positive electrode of the lithium-aluminum alloy which fell from the negative electrode will be greatly impaired. If it is a separator having a constituent element, as described above, since the breakthrough of the microporous film is suppressed by the presence of the nonwoven fabric, for example, compared to the case of using a separator composed only of a microporous film, The occurrence of the voltage failure can be suppressed to a higher degree.

  Further, in a separator having a microporous film and a non-woven fabric as constituent elements, when a sudden discharge such as a short circuit occurs in a non-aqueous electrolyte primary battery, the microporous film is configured by heat generated along with this. Shutdown characteristics such as increasing the internal resistance of the battery and ensuring the safety of the battery by melting the resin and closing the pores of the separator can be ensured. In addition, the nonwoven fabric also has an action as an electrolyte solution holding layer for increasing the amount of electrolyte solution held in the separator to further improve the battery capacity.

  In the battery of the present invention, when a separator having a microporous film and a nonwoven fabric as constituent elements is used, it is preferable that the microporous film is disposed so as to be in contact with the negative electrode and the nonwoven fabric is disposed so as to be in contact with the positive electrode. With such an arrangement, the breakage of the microporous film by the positive electrode active material on the surface of the positive electrode can be more highly suppressed by the action of the nonwoven fabric in contact with the positive electrode. The movement of the alloy to the positive electrode can be better prevented.

  When using the separator having the microporous film and the nonwoven fabric as constituent elements, the thickness of the nonwoven fabric is, for example, preferably 10 μm or more, more preferably 20 μm or more, preferably 80 μm or less, more preferably It is 60 μm or less, more preferably 50 μm or less. If the nonwoven fabric is too thin, the effect of preventing the occurrence of a short circuit or voltage failure due to the breakage of the microporous film in the wound electrode group may be reduced. In addition, if the nonwoven fabric is too thin, the amount of electrolyte retained in the separator is also reduced, and the battery capacity improvement effect may be reduced. On the other hand, if the nonwoven fabric is too thick, the battery capacity tends to decrease, and the resistance value of the separator increases, resulting in a decrease in load characteristics or sufficient discharge of electricity for the capacity of the battery. There is a case where a capacity is wasted such that it cannot be performed. When the nonwoven fabric has a thickness of 50 μm or less (that is, 10 μm or more, more preferably 20 μm or more and 50 μm or less) among the above thicknesses, it is particularly preferable because high capacity and load characteristics can be improved.

  Moreover, when using the separator which has the said microporous film and a nonwoven fabric as a component, the thickness of a microporous film becomes like this. Preferably it is 10 micrometers or more, More preferably, it is 20 micrometers or more, Preferably it is 40 micrometers or less. If the microporous film is too thin, a short circuit may easily occur due to the breakage of the microporous film in the wound electrode group. There is a risk of tearing. On the other hand, if the microporous film is too thick, the effect of improving the battery capacity may be reduced, and the resistance value of the separator increases, leading to a decrease in load characteristics or a waste of the above capacity. May occur.

  The width of the separator may be set so that the contact between the positive electrode and the negative electrode can be suppressed, but as described above, it is preferably larger than the width of the positive electrode and more preferably larger than the width of the negative electrode. Furthermore, in the separator having the microporous film and the nonwoven fabric as constituent elements, the width of the microporous film is preferably larger than the width of the negative electrode. When the width of the microporous film according to the separator is larger than the width of the negative electrode and the widest among the microporous film and the nonwoven fabric according to the positive electrode, the negative electrode, and the separator, the width of the electrode body having a wound structure The movement of the lithium-aluminum alloy that has fallen off from the negative electrode can be achieved to a higher degree by folding the microporous film protruding from both ends in the direction toward the winding center of the electrode body.

  On the other hand, in the separator having the microporous film and the non-woven fabric as constituent elements, the non-woven fabric has no effect by widening the microporous film as described above. Therefore, from the viewpoint of reducing the occupied volume of the nonwoven fabric in the battery, it is preferable to make the width of the nonwoven fabric smaller than that of the microporous film in the separator having the microporous film and the nonwoven fabric as constituent elements. It is more preferable that the width is equal to that of the negative electrode.

For example, in the case of a non-aqueous electrolyte primary battery having a positive electrode in which the porosity of the positive electrode mixture sheet is 35 to 50%, since the unevenness of the positive electrode surface in contact with the separator is large, the separator is broken through. However, even in such a case, the occurrence of a short circuit can be suppressed by employing the separator having the microporous film and the nonwoven fabric as constituent elements. In addition, the porosity of a positive mix sheet is calculated | required as follows. For example, when the positive electrode mixture sheet is made of manganese dioxide, ketjen black, and PVDF, the true specific gravity is 4.5 g / cm ³ , 2.0 g / cm ³ , and 2.2 g / cm ^{3, respectively.} The total X (g / cm ³ ) of the calculated mass of each constituent material contained per unit volume of the positive electrode mixture sheet is obtained, and the difference from the actual density Y (g / cm ³ ) of the positive electrode mixture sheet From [(X−Y) / X] × 100, the porosity (%) is obtained.

  Further, the maximum unevenness on the positive electrode surface (that is, the vertical distance between the horizontal line passing through the highest position of the highest convex part and the horizontal line passing through the lowest position of the lowest concave part) is larger than the thickness of the microporous film. Even if it is large (more specifically, for example, 40 μm or more), since the unevenness of the positive electrode surface is large, it is easy for the separator to break through. The separator is also effective for suppressing a short circuit in such a case.

Examples of the electrolyte solution according to the battery of the present invention include a solution prepared by dissolving LiPF ₆ , LiClO ₄ , LiCF ₃ SO _3, etc. as an electrolyte in a non-aqueous solvent such as an organic solvent.

Among the electrolytes described above, LiCF ₃ SO ₃ is preferably used from the viewpoint of further improving battery safety. When metallic lithium is used for the negative electrode and LiCF ₃ SO ₃ is used for the solute, fluorine ionized from LiCF ₃ SO ₃ reacts with active lithium during storage of the battery, and the negative electrode surface is in a passive state. Since a certain lithium fluoride film is formed and the internal resistance of the battery is increased, the discharge characteristics are deteriorated. However, in the battery of the present invention, a part of the negative electrode has a lithium-aluminum alloy, and this lithium-aluminum alloy has lower activity than lithium alone, so that fluorine ions and lithium present during storage -It is hard to react with an aluminum alloy, the production | generation of the passive state film in the negative electrode surface is suppressed, and the fall of a discharge characteristic can be suppressed.

  Since the cylindrical non-aqueous electrolyte primary battery of the present invention has good heavy load pulse discharge characteristics and heavy load continuous discharge characteristics, it is possible to take advantage of these characteristics to instantaneously generate large currents such as power supplies for alarm devices. It can be preferably used for various applications to which a conventionally known cylindrical non-aqueous electrolyte primary battery is applied, including applications that require both continuous discharge and continuous discharge at a large current.

  Hereinafter, the present invention will be described in detail based on examples. However, the following examples do not limit the present invention. In addition, "%" used in a present Example is a mass reference | standard (mass%) unless there is particular notice.

Example 1
For the cylindrical nonaqueous electrolyte primary battery of Example 1, [Preparation of positive electrode], [Preparation of negative electrode], [Preparation of wound electrode body], [Assembly of battery], [Post-treatment (preliminary discharge, aging)] Will be described in the order.

[Production of positive electrode]
First, a positive electrode mixture (in mass ratio, solid content: water content = 100: 30) was prepared by the following procedure. Carbon black having a BET specific surface area of 600 m ² / g: 3% and manganese dioxide (manufactured by Tosoh Corporation): 92% were mixed by a dry method using a planetary mixer for 5 minutes, and then water was added to a solid content of 20% ( Mass ratio) and mixed for 5 minutes. Prepare PTFE dispersion ("D-1" manufactured by Daikin Industries, Ltd.) in an amount corresponding to 5% of the solid content of the positive electrode mixture, dilute it with the remaining water, and add to the above mixture And mixed for 5 minutes to obtain a positive electrode mixture.

Using the above positive electrode mixture, two rolls having a diameter of 250 mm, adjusting the roll temperature to 125 ± 5 ° C., press pressure: 7 ton / cm, roll interval: 0.4 mm, rotation speed: 10 rpm The sheet was rolled and rolled. The positive electrode mixture (preliminary sheet) that passed through the roll was dried at 105 ± 5 ° C. until the residual moisture was 2% or less. Next, the dried preliminary sheet was pulverized using a pulverizer. At this time, the preliminary sheet was pulverized until it became twice or more the original apparent volume. Most of the particle size after pulverization was 1 mm or less, and PTFE added as a binder was also cut into fibers having a length of 1 mm or less. The pulverized material was formed into a sheet again by a roll. The interval between the rolls was adjusted to 0.6 ± 0.05 mm, and a positive electrode mixture sheet was obtained by forming into a sheet under the conditions of roll temperature: 125 ± 10 ° C., press pressure: 7 ton / cm, and rotation speed: 10 rpm. The obtained positive electrode mixture sheet has a thickness of 1.0 mm and corresponds to 5.9% of the inner diameter of the outer can. Moreover, the density of the positive mix sheet was 2.5 g / cm < ³ >, and the porosity calculated | required by the said method was 42%. This positive electrode mixture sheet is cut into a positive electrode mixture sheet for inner circumference (width: 38 mm, length: 51 mm in FIG. 2), a width: 38 mm, and a length: 62 mm. The positive electrode mixture sheet for the outer periphery (the positive electrode mixture sheet 41 on the right side in FIG. 2) was obtained.

As the positive electrode current collector, an expanded metal made of stainless steel (SUS316) was used. The expanded metal was cut into a width of 34 mm and a length of 56 mm, and a stainless steel ribbon having a thickness of 0.1 mm and a width of 3 mm was attached to the center in the length direction by resistance welding as a positive electrode lead body. . Further, a carbon paste (manufactured by Nippon Graphite Co., Ltd.) was applied to the expanded metal so as not to crush the mesh, and then dried at a temperature of 105 ± 5 ° C. to obtain a positive electrode current collector. The coating amount of the carbon paste was set to 5 mg / cm ² after drying.

  Next, in a state where the positive electrode current collector is interposed between the positive electrode mixture sheet for the inner periphery and the positive electrode mixture sheet for the outer periphery, only one end in the length direction is fixed and the three parties are integrated. . Specifically, the positive electrode mixture sheet for the inner periphery and the positive electrode mixture sheet for the outer periphery are aligned with one end in the length direction, and the end of the positive electrode current collector is composed of two positive electrode mixture sheets. Set the two so that they do not protrude from one end, and in that state, press the 5mm part of the two positive electrode mixture sheets from the end where both are aligned, so that the three parties are integrated. did. Thereafter, the two positive electrode mixture sheets and the positive electrode current collector were integrated with hot air at 250 ± 10 ° C. for 6 hours to obtain a sheet-like positive electrode having a width of 38 mm.

[Preparation of negative electrode (negative electrode precursor)]
The negative electrode has a width: 37 mm, a length: 170 mm, a thickness: 10 μm on a copper foil (negative electrode current collector), a width: 37 mm, a length: 87 mm, a thickness: 0.30 mm metal lithium foil, and a width: 37 mm. Further, a metal lithium foil having a length of 50 mm and a thickness of 0.30 mm is arranged, and a width: 27 mm, a length: 85 mm, a thickness: 6 μm, a width: 27 mm, a length: 48 mm, and a thickness: 6 μm aluminum foil, with one end and the one end in the width direction of the metal lithium foil (the end that becomes the lower side of the battery when inserted into the outer can as an electrode group with a wound structure) (In this case, the width of the aluminum foil is 73.0% with respect to the width of the metal lithium foil). First, a negative electrode lead made of nickel having a width of 3 mm, a length of 20 mm, and a thickness of 0.1 mm was pressure-bonded to a metal lithium foil having a length of 50 mm. Thereafter, the two metal lithium foils are disposed on the copper foil in a state of being separated from each other, and the aluminum foil is disposed on each of the two metal lithium foils to form a sheet-like negative electrode ( A sheet-like negative electrode precursor before forming a lithium-aluminum alloy (hereinafter referred to as “sheet-like negative electrode” for convenience) was prepared.

[Preparation of wound electrode group]
A non-woven fabric having a width of 42 mm, a length of 170 mm and a thickness of 20 μm is applied to a microporous polyethylene film [“Hypore” manufactured by Asahi Kasei Co., Ltd. (trade name)] having a width of 45 mm, a length of 170 mm and a thickness of 20 μm. The length of the microporous polyethylene film is laminated by aligning one end in the direction with one end in the width direction of the microporous polyethylene film (the end on the upper side of the battery when it is inserted into the outer can as a group of wound electrodes) A separator was manufactured by heat welding at a position 65 mm from one end in the direction.

  A separator was pasted on the copper foil of the sheet-like negative electrode (adhesive tape between the places where the two metal lithium foils were placed, where the copper foil surface was not covered with metal lithium foil, etc.) via an adhesive tape. . When attaching the separator to the negative electrode, the non-woven fabric surface is the positive electrode side, and the heat-welded part between the microporous film of the separator and the non-woven cloth is included in the adhesive part with the adhesive tape. Arranged so that one end protrudes 1.5 mm from one end of the negative electrode (Note that both the “one end” of the separator and the “one end” of the negative electrode are inserted into the outer can as an electrode group of a wound structure. To the upper end of the battery). Next, centering on the heat-welded part between the microporous film of the separator and the nonwoven fabric, the separator was sandwiched between two winding cores having a diameter of 3.5 mm and wound once. Next, after winding the negative electrode together with the separator once, the side on which the sheet-like positive electrode was fixed was placed on the winding core side and wound. After winding, the copper foil covered the outermost periphery. As shown in FIG. 2, on the surface of the electrode group of the winding structure on the battery bottom side, the portion protruding from the positive electrode of the separator is bent toward the winding center side of the electrode group of the winding structure. The end face of the positive electrode was covered with a separator on the battery bottom side surface of the group.

[Battery assembly]
An assembly process of the cylindrical non-aqueous electrolyte primary battery will be described with reference to FIG. A polypropylene insulating plate 14 having a thickness of 0.2 mm is inserted into an inner bottom portion 2a of a bottomed cylindrical outer can 2 made of nickel-plated iron cans, and an electrode group 3 having a wound structure is formed thereon. The lead body 15 was inserted with the posture facing upward. The negative electrode lead body 16 of the electrode group 3 was resistance welded to the inner surface of the outer can 2, and the positive electrode lead body 15 was resistance welded to the lower surface of the terminal body 9 after inserting the insulating plate 10. At this point, the insulation resistance was measured and it was confirmed that there was no short circuit.

As the electrolyte, a non-aqueous solution prepared by dissolving LiClO ₄ at a concentration of 0.5 mol / l in a mixed solvent of propylene carbonate and dimethoxyethane (volume ratio of 1: 2) was prepared, and this was used as an outer can. 3.5 ml was injected into 2. Injection was divided into three times, and the whole amount was injected while reducing the pressure in the final step. After injecting the electrolytic solution, the lid plate 7 is fitted into the upper opening of the outer can 2 and the inner peripheral portion of the opening end of the outer can 2 and the outer peripheral portion of the lid plate 7 are welded by laser welding. 2 openings were sealed.

[Post-treatment (preliminary discharge, aging)]
The sealed battery was pre-discharged with a resistance of 1Ω for 30 seconds, stored at 70 ° C. for 6 hours, then subjected to a secondary pre-discharge with a constant resistance of 1Ω for 1 minute, and lithium-aluminum on the separator-side surface of the sheet-like negative electrode. An alloy was formed. The battery after the preliminary discharge was aged at room temperature for 7 days, and the open circuit voltage was measured to confirm that a stable voltage was obtained. The non-cylindrical shape having an outer diameter of 17.0 mm and a total height of 45.0 mm A water electrolyte primary battery was obtained. The ratio of the negative electrode capacity to the positive electrode capacity of this battery was 1.00.

Example 2
A cylindrical non-aqueous electrolyte primary battery was produced in the same manner as in Example 1 except that the two aluminum foils used in the production of the sheet-like negative electrode were changed to those having a width of 18 mm. The width of the aluminum foil according to the negative electrode in Example 2 is 48.6% with respect to the width of the metal lithium foil.

Example 3
A cylindrical nonaqueous electrolyte primary battery was produced in the same manner as in Example 1 except that the two aluminum foils used were changed to those having a width of 8 mm in the production of the sheet-like negative electrode. The width of the aluminum foil according to the negative electrode in Example 3 is 21.6% with respect to the width of the metal lithium foil.

Example 4
A microporous polyethylene film having a width of 42 mm is used in the production of the electrode group having a winding structure, and the portion protruding from the positive electrode of the separator is formed on the surface of the battery bottom side of the electrode group having the winding structure. A cylindrical non-aqueous electrolyte primary battery was produced in the same manner as in Example 1 except that it was not bent toward the winding center side of the group and the end face of the positive electrode was not covered with a separator.

Example 5
In the production of the sheet-like negative electrode, a cylindrical nonaqueous electrolyte primary battery was produced in the same manner as in Example 4 except that the two aluminum foils used were arranged at the center in the width direction of the metal lithium foil.

Comparative Example 1
A cylindrical non-aqueous electrolyte primary battery was produced in the same manner as in Example 5 except that in the production of the sheet-like negative electrode, the two aluminum foils used were changed to those having a width of 36 mm. The width of the aluminum foil according to the negative electrode in Comparative Example 1 is 97.3% with respect to the width of the metal lithium foil.

Comparative Example 2
In the production of the sheet-like negative electrode, a cylindrical non-aqueous electrolyte primary battery was produced in the same manner as in Example 5 except that the two aluminum foils used were changed to those having a width of 30 mm. The width of the aluminum foil according to the negative electrode in Comparative Example 2 is 81.1% with respect to the width of the metal lithium foil.

Comparative Example 3
A cylindrical nonaqueous electrolyte primary battery was produced in the same manner as in Example 5 except that the two aluminum foils used were changed to 3.5 mm in the production of the sheet-like negative electrode. The width of the aluminum foil according to the negative electrode in Comparative Example 3 is 9.5% with respect to the width of the metal lithium foil.

Comparative Example 4
A cylindrical nonaqueous electrolyte primary battery was produced in the same manner as in Example 1 except that two aluminum foils were not used in the production of the sheet-like negative electrode.

  The cylindrical nonaqueous electrolyte primary batteries of Examples 1 to 5 and Comparative Examples 1 to 4 were subjected to the following discharge capacity measurement and pulse discharge characteristic evaluation. The results are shown in Table 1.

[Discharge capacity]
Each cylindrical non-aqueous electrolyte primary battery was continuously discharged at 20 ° C. with a current value of 300 mA, and the discharge capacity until the battery voltage reached 2.0 V was measured. In addition, the number of samples of each battery was set to five, and the average value was made into the discharge capacity of the battery of each Example and a comparative example.

[Pulse discharge characteristics]
For each cylindrical non-aqueous electrolyte primary battery (battery different from that for which the discharge capacity measurement was performed), the minimum voltage was measured when pulse discharge was performed at −20 ° C. with a current value of 300 mA for 1 s.

  In Table 1, “Al foil width / Li foil width” means the width of the aluminum foil relative to the width of the metal lithium foil in the sheet-like negative electrode (precursor), and “None” in Comparative Example 4 is the aluminum foil. It means that there is no. The “lower end” in the column “Al foil arrangement” in Table 1 and Table 2 below refers to the end on the battery bottom side of the wound electrode body in the width direction of the aluminum foil. “Center” means that the central portion in the width direction of the aluminum foil is aligned with the central portion in the winding axis direction of the electrode body of the winding structure. , Respectively. Furthermore, “exist” in the column of “separator folding” in Table 1 and Table 2 below indicates that the separator is bent toward the winding center side on the surface of the battery bottom side of the electrode body having a winding structure. `` None '' means that the separator was not folded to the winding center side on the battery bottom side surface of the electrode structure having a winding structure, and the end of the positive electrode was not covered, I mean.

  As shown in Table 1, the cylindrical non-aqueous electrolyte primary batteries of Examples 1 to 5 have a large discharge capacity at heavy load continuous discharge, and a high minimum voltage at 300 mA for 1 s pulse discharge. It has pulse discharge characteristics. On the other hand, the batteries of Comparative Example 1 and Comparative Example 2 in which the width of the aluminum foil is wider than the appropriate range are inferior in continuous discharge characteristics under heavy load compared to the batteries of the examples. The battery of Comparative Example 3 having a narrower than the appropriate range and the battery of Comparative Example 4 having a negative electrode prepared without using an aluminum foil (that is, having no lithium-aluminum alloy) In comparison, the minimum voltage during pulse discharge is low, and the pulse discharge characteristics are inferior.

  The battery bottom side end of the electrode structure having a winding structure in the width direction of the aluminum foil is aligned with the battery bottom side end of the electrode body, and the battery bottom side of the electrode body having the winding structure The battery of Example 1 in which the separator was bent to the winding center side to cover the end of the positive electrode, and the arrangement of the aluminum foil was the same as that of the battery of Example 1, and the electrode structure of the winding structure In the battery bottom surface, the battery of Example 4 in which the separator was not bent to the winding center side and the end portion of the positive electrode was not covered, and the center portion in the width direction of the aluminum foil were connected to the electrode body having a winding structure. Example 5 in which the separator was not bent to the winding center side and the end of the positive electrode was not covered on the surface on the battery bottom side of the electrode body having a winding structure in accordance with the central part in the winding axis direction. The following vibration test was performed on the battery.

  The vibration test was performed as follows. The process of adding vibration for 90 minutes in the Z direction with a vibration frequency range of 10 to 55 Hz and a maximum piece amplitude of 0.8 mm for each battery is defined as one cycle, and after three cycles (total 4.5 hours), The lithium-aluminum alloy leaked from the upper and lower ends of the electrode group having a wound structure was confirmed. Specifically, the lithium-aluminum alloy attached to the upper surface of the insulating plate 14 at the bottom of the outer can in contact with the lower surface of the electrode group having the winding structure and the lower surface of the upper insulating plate 10 in contact with the upper surface of the electrode group having the winding structure. Was confirmed visually. The results are shown in Table 2.

  As can be seen from Table 2, in the battery of Example 1, the adhesion of the lithium-aluminum alloy was not confirmed on the lower surface of the insulating plate 10 and the upper surface of the insulating plate 14 by the vibration test. On the other hand, in the battery of Example 4, it was found that the adhesion of the lithium-aluminum alloy was confirmed on the upper surface of the insulating plate 14 and leaked from the lower surface of the electrode group. Further, in the battery of Example 5, it was found that some adhesion of the lithium-aluminum alloy was confirmed on the lower surface of the insulating plate 10 and the upper surface of the insulating plate 14 and leaked from the upper and lower surfaces of the electrode group. Therefore, in order to suppress the deterioration of the battery characteristics due to the vibration of the battery to a higher degree, the central portion of the aluminum foil in the width direction is wound around the winding shaft in the electrode body having the winding structure as in the battery of Example 1. It is arranged so that it is located on the surface side that is the battery bottom side from the center part of the direction, and on the battery bottom side surface of the electrode structure of the winding structure, the separator is bent toward the winding center side, and the end of the positive electrode is It is preferable to cover.

It is a vertical side view which shows typically an example of the cylindrical nonaqueous electrolyte primary battery of this invention. It is a principal part expanded sectional view which shows typically an example of the electrode group of the winding structure used for the cylindrical nonaqueous electrolyte primary battery of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylindrical nonaqueous electrolyte primary battery 3 Electrode group of winding structure 4 Positive electrode 5 Negative electrode 6 Separator 51 Metal lithium foil or lithium alloy foil 52 Aluminum foil 53 Negative electrode collector

Claims (2)

A positive electrode containing manganese dioxide or fluorinated graphite, and a negative electrode, a cylindrical non-aqueous electrolyte primary battery having a wound electrode group wound in a spiral shape through a separator,
The negative electrode has a metal lithium-containing layer and a current collector, and a lithium-aluminum alloy is formed on the surface opposite to the current collector in a portion of 20 to 75% of the width of the metal lithium-containing layer. Has been
The central part in the width direction of the portion where the lithium-aluminum alloy is formed in the negative electrode is located closer to the battery bottom than the central part in the winding axis direction in the electrode group of the winding structure, and the separator Is larger than the width of the positive electrode,
A portion of the separator that protrudes from the positive electrode on the surface of the battery bottom side of the electrode group having the winding structure is bent toward a winding center side of the electrode group having the winding structure. Cylindrical non-aqueous electrolyte primary battery. In producing a cylindrical non-aqueous electrolyte primary battery having an electrode group having a winding structure in which a positive electrode containing manganese dioxide or graphite fluoride and a negative electrode are wound in a spiral shape via a separator,
A current collector is disposed on one side of the metal lithium foil or lithium alloy foil, and the surface of the metal lithium foil or lithium alloy foil opposite to the current collector is 20 to 75% of the width of the metal lithium foil or lithium alloy foil. width using the negative electrode was placed an aluminum foil having a,
The central portion in the width direction of the aluminum foil is disposed so as to be located on the surface side that is the battery bottom side than the central portion in the winding axis direction in the electrode group of the winding structure, and the width of the separator is Larger than the width of the positive electrode,
On the surface of the electrode group having the winding structure on the battery bottom side, the portion protruding from the positive electrode of the separator is bent toward the winding center side of the electrode group having the winding structure, and then the winding structure. A method for producing a cylindrical non-aqueous electrolyte primary battery, wherein the electrode group is inserted into an outer can .

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