JP2007115478A - Nonaqueous electrolyte battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte battery capable of suppressing voltage drop when the shock is applied from the outside by vibration, falling down or the like. <P>SOLUTION: The nonaqueous electrolyte battery is equipped with a film outer packaging member having a flat shape and formed by joining a first surface and a second surface on the opposite side by heat sealing; an electrode group housed in the film outer packaging member and containing a positive electrode, a negative electrode, and a separator; a positive terminal 11 electrically connected to the positive electrode; and a negative terminal 13 electrically connected to the negative electrode. The positive terminal 11 and the negative terminal 13 are drawn out of the same heat sealing parts of the outer packaging member or the heat sealing parts facing each other, and the first surface and the second surface are joined on the inner surfaces in a region facing to a space positioned between the heat sealing part from which at least one of the positive terminal and the negative terminal is drawn out and the electrode group. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a non-aqueous electrolyte battery.

  In recent years, with the development of electronic devices, there has been a demand for the development of secondary batteries that are small and light, have high energy density, and can be repeatedly charged and discharged. As such a secondary battery, a negative electrode using lithium or a lithium alloy as an active material and a suspension in which a suspension containing an active material of oxide, sulfide or selenide such as molybdenum, vanadium, titanium or niobium is applied. A non-aqueous electrolyte secondary battery including a positive electrode made of an electric body and a non-aqueous electrolyte is known.

  Also, non-aqueous using a current collector in which a suspension containing a carbonaceous material that occludes and releases lithium ions, such as coke, graphite, carbon fiber, a resin fired body, and pyrolytic vapor phase carbon, is applied to the negative electrode. An electrolyte secondary battery has been proposed. The secondary battery can improve the deterioration of the negative electrode characteristics due to the dendrite precipitation, so that the battery life and safety can be improved.

  On the other hand, instead of the conventional metal can, the exterior member has an external impact protection film typified by nylon film as the outermost layer for the purpose of further thinning, for the purpose of moisture and light shielding typified by aluminum foil It is advancing to use what was formed from the composite film which arrange | positioned the metal layer mentioned above in the middle, and arranged the electrode group and the heat-fusible resin film for sealing electrolyte solution in the innermost layer.

  A non-aqueous electrolyte secondary battery equipped with an exterior member formed from such a film material can be developed in a wide variety of shapes at a relatively low cost compared to those using conventional metal cans. In particular, in the field where high capacity and high output of the battery are required, those using a film material as the exterior member have become mainstream.

  However, considering the safety of the battery, on the other hand, the strength of the film material is generally weaker than that of a metal can, so overheating due to overcharge and overdischarge, and explosion from internal pressure increase due to gas generation, etc. On the other hand, it is difficult and advantageous, but in the case of vibration or drop impact, the container itself is deformed by the movement of the electrode group inside the container, and the internal resistance is likely to increase due to the disconnection of the terminal, or a local short-circuit occurs.

  In this state, even when charging / discharging is repeated normally, there is a possibility that the battery itself may be ignited due to heat generation in the defective portion.

In order to prevent a decrease in battery reliability during a drop impact, in Patent Document 1, along the direction in which the electrode terminal 6 extends to the first side surface 10s of the first recess 10h in which the battery core 40 is accommodated. Thus, a first projecting portion 11t projecting inside the first recess 10h is formed so as to approach the battery core 40.
JP 2003-77426 A

  The present invention provides a nonaqueous electrolyte battery in which a voltage drop when an impact is applied from the outside due to vibration, dropping, or the like is suppressed.

The nonaqueous electrolyte battery according to the present invention has a flat shape, and is housed in the exterior member made of a film, in which the first surface and the second surface opposite to the first surface are joined by thermal fusion, A non-aqueous electrolyte battery comprising an electrode group including a positive electrode, a negative electrode, and a separator, a positive electrode terminal electrically connected to the positive electrode, and a negative electrode terminal electrically connected to the negative electrode,
The positive electrode terminal and the negative electrode terminal are drawn to the outside from the same heat fusion part of the exterior member or the heat fusion parts opposite to each other,
In the region where the first surface and the second surface are opposed to a space located between the heat fusion part from which at least one of the positive electrode terminal and the negative electrode terminal is drawn out and the electrode group, The inner surfaces are joined to each other.

In addition, the nonaqueous electrolyte battery according to the present invention has a flat shape, and is housed in the exterior member made of a film in which the first surface and the second surface opposite to the first surface are bonded by thermal fusion. A non-aqueous electrolyte battery comprising an electrode group including a positive electrode, a negative electrode, and a separator, a positive electrode terminal electrically connected to the positive electrode, and a negative electrode terminal electrically connected to the negative electrode,
The positive electrode terminal and the negative electrode terminal are drawn to the outside from the same heat fusion part of the exterior member or the heat fusion parts opposite to each other,
In the region where the first surface and the second surface are opposed to a space located between the heat fusion part from which at least one of the positive electrode terminal and the negative electrode terminal is drawn out and the electrode group, Insulating spacers are interposed.

  According to the present invention, it is possible to suppress a voltage drop when an external impact is applied to the nonaqueous electrolyte battery due to vibration or dropping.

  According to the nonaqueous electrolyte battery according to the present invention, it is possible to suppress the movement of the electrode group in the exterior member when an impact is applied from the outside, and to reduce the impact applied to the electrode group and the exterior member. it can. The external impact here is not the case where the exterior member is broken or the battery itself is deformed by external force, but it assumes vibration during transportation and indirect force applied after packaging into an external device. is doing.

  In a nonaqueous electrolyte battery having an exterior member formed of a film material, the positive electrode terminal and the negative electrode terminal are pulled out from the exterior member to the outside, so that the positive electrode terminal and the negative electrode terminal are sandwiched and fixed between the film materials. However, the electrode group is in contact with the exterior member and is not fixed. For this reason, when an impact is applied in the direction of the gap existing inside the exterior member, the electrode group easily moves in the impact direction, and the exterior member may be deformed by the collision of the electrode group in a stronger impact.

  If the connection between the positive and negative electrode terminals and the electrode group is disconnected due to this impact, or if the positive or negative electrode terminal or electrode group is temporarily broken and then the disconnected part is in contact with the impact, the resistance is locally increased. Therefore, even if charging / discharging is repeated normally, there is a possibility that the battery itself may be ignited due to heat generation in the defective portion. In addition, deformation of the electrode group itself may cause a local short circuit, causing heat generation and ignition.

  As in the present invention, in the first surface and the second surface facing the space located between the heat fusion part from which at least one of the positive electrode terminal and the negative electrode terminal is drawn out and the electrode group, the inner surfaces are When an external impact is applied, the movement of the electrode group can be restricted by the joint or the insulating spacer. As a result, the connection failure between the positive and negative terminals and the deformation of the electrode group can be suppressed, so that a voltage drop due to an internal short circuit when an external impact is applied can be suppressed. In addition, the formation of the joint portion and the fixing of the insulating spacer to the exterior member can be performed by, for example, heat sealing, use of an adhesive or a tape that does not affect the battery performance, but the method is simple. Heat bonding is desirable because sufficient bonding strength can be obtained and there is little risk of side reactions.

  First, the joint portion will be described.

  The area of the joint is 10% or more and 60% or less of the area (one side) facing the space located between the heat-sealed part from which at least one of the positive electrode terminal and the negative electrode terminal is drawn out and the electrode group. It is desirable to make it. This is due to the reason explained below. If the area of the bonded portion is less than 10%, the bonded portion may be peeled off by the collision of the electrode group. On the other hand, if the area of the joint exceeds 60%, the space inside the battery is reduced, and the holding space for the electrolyte is reduced. For this reason, there exists a possibility that liquid injection property may deteriorate and productivity may fall. In addition, battery characteristics such as output characteristics and charge / discharge cycle characteristics may deteriorate.

  The joining portion can be formed, for example, by forming a recess on the first surface or the second surface and joining the inner surface of the recess and the inner surface of the other surface. The shape of the recess is not particularly limited, but can be various shapes such as a cylindrical shape, an elliptical column shape, a triangular column shape, a quadrangular column shape, a polygonal column shape, and the like. It is easy to work with a cylindrical shape, and it is a quadrangular prism shape that improves the bonding strength.

  Moreover, it is desirable that the recess has a tapered shape. Thereby, the processing wrinkle at the time of forming a recessed part in a film material can be decreased. Furthermore, since the collision area of an electrode group and a recessed part can be enlarged, the effect which regulates the movement of an electrode group can be made higher.

  By providing the filling member for filling the gap in the recess, the joint can be pressurized from the outside to further improve the joint strength of the joint. In addition, it is possible to avoid the entry of foreign matter into the recess and to reinforce the battery strength.

  The filling member includes a flat plate portion fixed on the heat fusion portion from which at least one of the positive electrode terminal and the negative electrode terminal is drawn, and a projection portion formed in the flat plate portion and filled in the gap in the concave portion. Can be used. Such a filling member can further improve the joint strength of the joint. In addition, it is possible to avoid the entry of foreign matter into the recess and to reinforce the battery strength. Furthermore, the bonding strength between the filling member and the exterior member can also be improved.

  When the filling member has shock absorption, the impact resistance at the time of dropping can be further increased. Examples of the material having shock absorption include silicon rubber, urethane resin, nitrile butadiene rubber (NBR), and the like.

  Next, the insulating spacer will be described.

  The insulating spacer is not particularly limited as long as it is made of a material that does not affect the battery performance. For example, the insulating spacer can be made of a thermoplastic resin such as polyolefin (polyethylene, polypropylene).

  The bonding area (one side) between the insulating spacer and the exterior member is desirably 10% or more and 60% or less of the area of the region (single side) for the same reason as described for the joint portion.

  In particular, by forming a concave portion on the first surface or the second surface and fixing an insulating spacer between the surface on which the concave portion is formed and the other surface, a higher impact absorbing effect can be obtained in a simple manner. Can be obtained.

  Assuming the non-aqueous electrolyte battery of the present invention, vibration during transportation, and indirect force applied after being packed into an external device and protecting the battery surface portion so that external force is not directly applied to the battery, As a result of confirming the change in battery voltage when dropped several times from a certain height on concrete etc., it was confirmed that the amount of change can be remarkably reduced as compared with the battery of the conventional structure as shown in the examples described later. And a non-aqueous electrolyte battery effective for external impact resistance could be realized.

  The exterior member and the electrode group will be described.

1) Exterior member As the exterior member, one having a recess (cup portion) in which an electrode group is accommodated can be used. As the exterior member, a member in which the container and the sealing plate are integrated may be used, or a member in which the sealing plate and the container have different structures may be used.

  The film material forming the exterior member preferably contains at least a resin film. Examples of such a film material include a resin film, a laminate film containing a resin and a metal, and the like.

  Although the kind of resin to be used is not particularly limited, examples thereof include polyamide resins such as nylon and thermoplastic resins such as polyolefin resins (polyethylene, polypropylene, etc.).

  As the laminate film, for example, a film including a metal layer, a thermoplastic resin layer formed on one surface of the metal layer, and a protective layer formed on the opposite surface of the metal layer can be used. . The metal layer can be formed from, for example, aluminum or an aluminum alloy. The protective layer can be formed from, for example, a polyamide resin such as nylon or polyethylene terephthalate. The joining portion can be formed by thermally fusing the thermoplastic resin layers of the laminate film.

  In the laminate film, an adhesive layer, a gas barrier layer, or the like may be provided between the external protective layer, the metal layer, and the thermoplastic resin layer.

2) Electrode group What has a flat shape can be used for an electrode group. The flat electrode group is produced, for example, by winding the positive electrode and the negative electrode in a spiral shape via a separator, or alternately laminating the positive electrode and the negative electrode with a separator interposed therebetween.

  The positive electrode includes a current collector and a mixture layer supported on the current collector.

As the positive electrode active material, various oxides such as manganese dioxide, lithium manganese composite oxide (for example, LiMn ₂ O ₄ , LiMnO ₂ ), lithium-containing nickel oxide, lithium-containing cobalt oxide (for example, LiCoO ₂ ), Examples thereof include lithium-containing nickel cobalt oxide (for example, LiNi _0.8 Co _0.2 O ₂ ), lithium-containing iron oxide, vanadium oxide containing lithium, and chalcogen compounds such as titanium disulfide and molybdenum disulfide. In addition, the kind of positive electrode active material to be used can be made into 1 type or 2 types or more.

  As the current collector, a conductive substrate having a porous structure or a nonporous conductive substrate can be used. These conductive substrates can be formed from, for example, aluminum, stainless steel, or nickel.

  The negative electrode includes a current collector and a mixture layer supported on the current collector.

  As the negative electrode active material, lithium ions or materials that occlude and release lithium can be used. For example, a graphite material or a carbonaceous material (for example, graphite, coke, carbon fiber, spherical carbon, pyrolytic gas phase carbonaceous material) , Resin fired bodies, etc.), chalcogen compounds (eg, titanium disulfide, molybdenum disulfide, niobium selenide, etc.), light metals (eg, aluminum, aluminum alloys, magnesium alloys, lithium, lithium alloys, etc.), lithium titanium oxides ( For example, spinel type lithium titanate) can be used.

  As the current collector, a conductive substrate having a porous structure or a nonporous conductive substrate can be used. These conductive substrates can be formed from, for example, copper, aluminum, stainless steel, or nickel.

  As the separator, a microporous film, a woven fabric, a non-woven fabric, a laminate of the same material or different materials among these can be used. Examples of the material for forming the separator include polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene-butene copolymer. As a material for forming the separator, one type or two or more types selected from the types described above can be used.

  A non-aqueous electrolyte is held in the electrode group. The non-aqueous electrolyte includes a non-aqueous solvent and an electrolyte (for example, lithium salt) dissolved in the non-aqueous solvent. The form of this non-aqueous electrolyte can be liquid (non-aqueous electrolyte), gel or solid.

  Examples of the non-aqueous solvent include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), γ-butyrolactone (γ -BL), sulfolane, acetonitrile, 1,2-dimethoxyethane, 1,3-dimethoxypropane, dimethyl ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran and the like. Nonaqueous solvents may be used alone or in combination of two or more.

Examples of the electrolyte include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluoroarsenide (LiAsF ₆ ), and trifluoromethanesulfone. Examples thereof include lithium salts such as lithium acid lithium (LiCF ₃ SO ₃ ). The electrolyte may be used alone or in combination of two or more. The amount of the electrolyte dissolved in the non-aqueous solvent is preferably 0.2 mol / l to 2 mol / l.

[Example]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings described above.

Example 1
<Formation of exterior member>
Drawing was performed on a 0.095 mm thick exterior film composed of 0.025 mm thick nylon film / 0.04 mm thick aluminum foil / 0.03 mm thick polyethylene film, as shown in FIG. In addition, cylindrical recesses 1a to 1c having a depth of 3.5 mm were provided at three locations on one end portion on the short side, and cut into outer dimensions of 105 × 75 mm to obtain a sealing plate 2. The cylindrical recesses 1a to 1c were processed so as to protrude from the nylon film side (protective layer side) to the polyethylene film side (thermoplastic resin layer side). Further, the recesses 1a to 1c are provided with a taper 3 so that the diameter becomes smaller toward the protruding side.

  A similar exterior film is subjected to deep drawing to form a rectangular cup portion 4 having a depth of 4.0 mm, a length of 95 mm, and a width of 65 mm, and two short side direction locations 4 a and 4 b and two long side direction locations 4 c of the cup portion 4. , 4d, and a container 5 having an outer dimension of 105 × 75 mm provided with a 5 mm wide edge. The cup part 4 was processed so that the nylon film was on the outside.

<Production of electrode group>
First, 89 parts by weight of LiCoO ₂ powder as an active material, 8 parts by weight of graphite powder as a conductive filler and 3 parts by weight of polyvinylidene fluoride resin as a binder are mixed with 25 parts by weight of N-methylpyrrolidone to prepare a positive electrode paste. Prepared. This positive electrode paste was continuously applied to both sides of an aluminum foil hoop material having a thickness of 0.03 mm as a current collector so that uncoated portions remained on both sides, dried, and then rolled to form a positive electrode mixture layer. Thereafter, the coated part was cut out so that the outer dimension of the coated part was 80 × 60 mm and the dimension of the uncoated part 6 was 5 × 10 mm at a position 10 mm inside from the right end surface of the long side part.

  Next, after pulverizing the mesophase pitch-based carbon fiber, 100 parts by weight of the heat-treated carbon fiber powder was mixed with an aqueous solution containing 2 parts by weight of crosslinked rubber latex particles of carboxymethyl cellulose and styrene-butadiene to prepare a negative electrode paste. This negative electrode paste was continuously applied on both sides of a copper foil hoop material having a thickness of 0.015 mm as a current collector so that uncoated portions remained on both sides, dried, and then rolled to form a negative electrode mixture layer 7 After that, the outer dimensions of the coated portion were 81 × 61 mm, and the uncoated portion 8 was cut out to have a size of 5 × 10 mm at a position 10 mm inside from the left end surface of the long side portion, thereby forming a negative electrode.

  Next, after cutting a separator made of polyethylene microporous film into 168 × 64 mm, the long side is folded 180 ° in the center, and the long side both side ends 9 are heat-sealed with a width of 1 mm to form a bag part, A bag-shaped separator having an outer dimension of 84 × 64 mm and a bag portion inner dimension of 84 × 62 mm was produced.

  Next, after the positive electrode is inserted into the separator bag portion and the positive electrode and the separator are combined, the positive electrode uncoated portion 6 is extended to the right side, the negative electrode uncoated portion 8 is extended to the left side, and the negative electrode, separator + After stacking the negative electrode in the order of positive electrode, negative electrode, separator + positive electrode, and finally laminating 21 negative electrodes and 20 positive electrodes + separators, the insulating tape 10 By stopping, the positive electrode, the negative electrode, and the separator were fixed.

  Next, after joining the 20 aluminum foils of the positive electrode uncoated part 6 by ultrasonic welding, as shown in FIG. 4, the aluminum plate 11 with a thickness of 0.1 mm and an outer dimension of 30 × 10 mm is attached to the tip part. Was clamped in two and fixed by ultrasonic welding. The tip of the aluminum plate 11 was pulled out to the side opposite to the positive electrode uncoated portion 6 to form a positive electrode tab 11 (positive electrode terminal). After 21 copper foils of the negative electrode uncoated portion 8 were joined by ultrasonic welding, a negative electrode tab 13 (negative electrode terminal) made of a copper plate having a thickness of 0.1 mm and an outer dimension of 30 × 10 mm was attached to the tip of the positive electrode. Bonding was performed in the same manner as in the case.

  An acid-modified polyethylene film 12 having an outer dimension of 7 × 20 mm is prepared as a thermoplastic resin film having metal adhesion, and is heat-sealed to both sides of the positive tab 11 and the negative tab 13 at a position 3 mm from the short side tip. The electrode group having the structure shown in FIG. 3 was obtained.

<Preparation of electrolyte>
LiPF ₆ as an electrolyte is dissolved in a non-aqueous solvent in which ethylene carbonate (EC) and dimethyl carbonate (DMC) are mixed at a volume ratio of 1: 1 so as to have a concentration of 1 mol / l. Prepared.

<Production of nonaqueous electrolyte battery>
As shown in FIG. 5, the positive electrode tab 11 and the negative electrode tab 13 are drawn out from the short side edge 4 a to the cup 4 of the container 5, and the acid-modified polyethylene film 12 is short side edge 4 a of the container 5. The electrode group was housed so as to hang over.

  Next, the sealing plate 2 was superposed on the container 5 so that the polyethylene film side was inside. At the time of this superposition, in the space between the electrode group in the cup portion 4 and the short side edge portion 4a, the concave portion 1a is disposed on the right side of the positive electrode tab 11, and between the positive electrode tab 11 and the negative electrode tab 13. The concave portion 1 b was disposed, and the concave portion 1 c was disposed on the left side of the negative electrode tab 13. Next, the entire exterior member was inverted so that the cup portion 4 was positioned on the upper surface.

Subsequently, the two short side edge portions 4a and 4b were heat-sealed with a heat-sealing machine under the conditions of a temperature of 200 ° C., a pressure of 4.0 kgf / cm ² , and a heating time of 10 s. Thereafter, one of the unfused long side edges was heat-sealed with a heat-sealing machine under the conditions of a temperature of 180 ° C., a pressure of 4.0 kgf / cm ² , and a heating time of 5 s.

Subsequently, the inner surface of the three concave portions 1a to 1c of the sealing plate 2 (first surface) and the inner bottom surface (second surface) of the cup portion 4 facing each concave portion are heat-sealed. Then, heat fusion was performed under the conditions of a temperature of 180 ° C., a pressure of 4.0 kgf / cm ² , and a heating time of 5 s. The total area of the heat-sealed portion at the three concave portions was 21% of the area within the bottom of the cup portion 4 located between the electrode group and the short side edge portion 4a.

  Subsequently, after injecting the non-aqueous electrolyte into the cup part 4 from the unfused long side edge and impregnating the electrode group, the unfused long side edge is first fused. A nonaqueous electrolyte battery having the structure shown in FIG. 6 and having a thickness of 4 mm, a width of 75 mm, a length of 105 mm (excluding positive and negative electrode tab dimensions), and a capacity of 1500 mAh is 100. Individually produced.

(Example 2)
<Formation of exterior member>
The exterior film similar to that described in Example 1 is drawn, and as shown in FIG. 7, three rectangular parallelepiped concave portions 14a to 14c having a depth of 3.5 mm are provided at three positions on the short side, A sealing plate 15 cut out to a size of 105 × 75 mm was produced. The rectangular parallelepiped recesses 14a to 14c were processed so as to protrude from the nylon film side (protective layer side) to the polyethylene film side (thermoplastic resin layer side). Further, the recesses 14a to 14c are provided with a taper 16 so that the area decreases toward the protruding side. On the other hand, the container 5 having the structure shown in FIG.

  Except for using the exterior member described above, the structure shown in FIG. 9 is used in the same manner as in Example 1, with a thickness of 4 mm, a width of 75 mm, a length of 105 mm (excluding positive and negative electrode tab dimensions), and a capacity of 1500 mAh. 100 non-aqueous electrolyte batteries were produced.

  That is, as shown in FIG. 9, the positive electrode tab 11 and the negative electrode tab 13 are drawn out from between the short side edge 4 a of the container 5 and the short side end of the sealing plate 15. In the space between the electrode group in the cup portion 4 and the short side edge portion 4a, a concave portion 14a is arranged on the right side of the positive electrode tab 11, and a concave portion 14b is arranged between the positive electrode tab 11 and the negative electrode tab 13, A recess 14 c is arranged on the left side of the negative electrode tab 13. The inner surfaces (first surface) of the recesses 14a to 14c and the bottom inner surface (second surface) of the cup portion 4 facing the respective recesses are joined by thermal fusion. The total area of the heat-sealed portion at the three concave portions was 27% of the area within the bottom of the cup portion 4 located between the electrode group and the short side edge portion 4a.

(Example 3)
<Formation of exterior member>
As shown in FIG. 10, an exterior film similar to that described in Example 1 is drawn into two rectangular parallelepiped recesses 17a to 17d each having a depth of 3.5 mm as shown in FIG. The sealing board 18 cut out in the location and the outer dimension 115x75mm was produced. The rectangular parallelepiped recesses 17a to 17d were processed so as to protrude from the nylon film side (protective layer side) to the polyethylene film side (thermoplastic resin layer side). Further, the recesses 17a to 17d are provided with a taper 19 so that the area decreases toward the protruding side.

  The same exterior film as Example 1 was deep-drawn, and as shown in FIG. 11, a rectangular cup part 20 having a depth of 4.0 mm, a length of 105 mm, and a width of 65 mm, and two places in the short side direction of the cup part 20 A container 21 having an outer dimension of 115 × 75 mm in which an edge portion having a width of 5 mm was provided at 20 a and 20 b and two locations 20 c and 20 d in the long side direction was produced. The cup part 20 was processed so that the nylon film was on the outside.

<Production of electrode group>
After forming the positive electrode mixture layer in the same manner as in Example 1, the positive electrode was cut out so that the outer dimension of the coated portion was 80 × 60 mm and the uncoated portion 22 was 5 × 20 mm.

  Furthermore, after the negative electrode mixture layer 7 was formed by the same method as in Example 1, the negative electrode was cut out so that the outer dimension of the coated portion was 81 × 61 mm and the uncoated portion 23 was 5 × 20 mm.

  In addition, a bag-shaped separator was prepared in the same manner as in Example 1, and after the positive electrode was inserted into the bag portion of the separator and the positive electrode and the separator were combined, the negative electrode, the separator + positive electrode, the negative electrode, and the separator + positive electrode in this order from the bottom layer. After stacking 21 sheets of negative electrodes and 20 sheets of positive electrodes + separators in the final layer, the stacked electrodes are clamped with insulating tape 10 at the four corners to form positive electrodes, negative electrodes, The separator was fixed. The positive electrode uncoated portion 22 was projected from the end portion on the short side of the laminated electrode. Moreover, the negative electrode non-application part 23 was made to protrude from the short side edge part on the opposite side of a laminated electrode.

  Next, 20 aluminum foils of the positive electrode uncoated portion 22 were joined by ultrasonic welding, and the tip portion was made of aluminum having a thickness of 0.1 mm and an outer dimension of 30 × 20 mm as shown in FIG. The plate 24 was sandwiched between two folded pieces and fixed by ultrasonic welding. The tip of the aluminum plate 24 was drawn out to the side opposite to the positive electrode uncoated portion 22 to form a positive electrode tab 24 (positive electrode terminal). After 21 copper foils of the negative electrode uncoated portion 23 were joined by ultrasonic welding, a negative electrode tab 25 (negative electrode terminal) made of a copper plate having a thickness of 0.1 mm and an outer dimension of 30 × 20 mm was attached to the tip portion of the positive electrode. Bonding was performed in the same manner as in the case.

  An acid-modified polyethylene film 26 having an outer dimension of 7 × 30 mm is prepared as a thermoplastic resin film having metal adhesion, and is heat-sealed to both sides at a position 3 mm from the short-side ends of the positive electrode tab 24 and the negative electrode tab 25. The electrode group having the structure shown in FIG. 12 was obtained.

<Preparation of non-aqueous electrolyte>
Prepared in the same manner as in Example 1.

<Production of nonaqueous electrolyte battery>
As shown in FIG. 13, a positive electrode tab 24 is drawn out from the short side edge 20a and a negative electrode tab 25 is drawn out from the short side edge 20b to the cup 20 of the container 21, and acid-modified polyethylene. The electrode group was accommodated so that the film 26 spans the short side edges 20a and 20b of the container 21.

  Next, the sealing plate 18 was superposed on the container 21 so that the polyethylene film side was inside. During the superposition, the concave portions 17a and 17b were disposed on both sides of the positive electrode tab 24 in the space between the electrode group in the cup portion 20 and the short side edge portion 20a. Further, in the space between the electrode group in the cup portion 20 and the short side edge portion 20b, the concave portions 17c and 17d are arranged on both sides of the negative electrode tab 25. Next, the entire exterior member was inverted so that the cup portion 20 was positioned on the upper surface.

Subsequently, the two short side edge portions 20a and 20b were heat-sealed with a heat-sealing machine under the conditions of a temperature of 200 ° C., a pressure of 4.0 kgf / cm ² , and a heating time of 10 s. Thereafter, one of the unfused long side edges was heat-sealed with a heat-sealing machine under the conditions of a temperature of 180 ° C., a pressure of 4.0 kgf / cm ² , and a heating time of 5 s.

Subsequently, the inner surface of the four concave portions 17a to 17d of the sealing plate 18 (first surface) and the inner bottom surface (second surface) of the cup portion 20 facing the respective concave portions are heat fusion machines. Then, heat fusion was performed under the conditions of a temperature of 180 ° C., a pressure of 4.0 kgf / cm ² and a heating time of 5 s. The total area of the heat-sealed portions at the two locations of the recesses 17a and 17b was 18% of the area within the bottom of the cup portion 20 located between the electrode group and the short side edge 20a. On the other hand, the total area of the heat-sealed portion at the two locations of the recesses 17c and 17d was 18% of the area inside the bottom of the cup portion 20 located between the electrode group and the short side edge portion 20b.

  Subsequently, after injecting the non-aqueous electrolyte into the cup part 20 from the unfused long side edge and impregnating the electrode group, the unfused long side edge is first fused. A nonaqueous electrolyte battery having a structure shown in FIG. 14 and having a structure of 4 mm in thickness, 75 mm in width, 115 mm in length (excluding positive and negative electrode tab dimensions), and a capacity of 1500 mAh is 100. Individually produced.

Example 4
<Formation of exterior member>
As shown in FIG. 15, a rectangular parallelepiped concave portion 27 a to 27 c having a depth of 0.5 mm is provided at three locations on the short side end portion by drawing a similar exterior film as described in Example 1, and A sealing plate 28 cut out to a size of 105 × 75 mm was produced. The rectangular parallelepiped concave portions 27a to 27c were processed so as to protrude from the nylon film side (protective layer side) to the polyethylene film side (thermoplastic resin layer side). Further, the recesses 27a to 27c are provided with a taper so that the cross-sectional area decreases toward the protruding side. On the other hand, the container 5 having the structure shown in FIG.

<Production of electrode group>
The electrode group shown in FIG. 19 was produced by the same method as in Example 1.

<Preparation of non-aqueous electrolyte>
Prepared in the same manner as in Example 1.

<Production of nonaqueous electrolyte battery>
As shown in FIG. 17, a rectangular parallelepiped polyethylene insulator 29 (insulating spacer) having an outer dimension of 3.0 mm × 8.0 mm × 60.0 mm was produced. As shown in FIG. 18, the insulator 29 is arranged on the short side 4 a side in the cup portion 4 of the container 5.

  Next, as shown in FIG. 20, the electrode group is drawn to the cup portion 4 of the container 5, the positive electrode tab 11 and the negative electrode tab 13 are drawn out from the short side edge 4 a across the insulator 29, and acid-modified. The polyethylene film 12 was stored so as to hang over the short side edge 4a.

  Next, the sealing plate 28 was superposed on the container 5 with the polyethylene film side inside. At the time of this superposition, the concave portion 27 a is disposed on the right side of the positive electrode uncoated portion 6 on the insulator 29, and the concave portion 27 c is disposed on the left side of the negative electrode uncoated portion 8 on the insulator 29. A concave portion 27 c was disposed between the uncoated portion 6 and the negative electrode uncoated portion 8. Subsequently, the whole exterior member was inverted so that the cup part 4 became an upper surface.

  Subsequently, one of the two short side edges and the long side edge was heat-sealed in the same manner as in Example 1.

Subsequently, the bottom inner surface of the concave portions 27a to 27c of the sealing plate 28 (first surface) and the portion of the bottom inner surface (second surface) of the cup portion 4 facing the concave portions 27a to 27c are Heating and pressing is performed under the conditions of 200 ° C., pressure force of 4.0 kgf / cm ² , and heating time of 5 s, and insulation is provided between the bottom inner surfaces of the recesses 27a to 27c and the cup portion 4 bottom inner surface facing the recesses 27a to 27c. The body 29 was heat-sealed. The heat fusion area between the sealing plate 28 and the insulator 29 and the heat fusion area between the cup portion 4 and the insulator 29 are respectively the bottom of the cup portion 4 located between the electrode group and the short side edge 4a. It was 27% of the inner area.

  Subsequently, after injecting the non-aqueous electrolyte into the cup part 4 from the unfused long side edge and impregnating the electrode group, the unfused long side edge is first fused. A non-aqueous electrolyte battery having the structure shown in FIG. 21 and having a thickness of 4 mm, a width of 75 mm, a length of 105 mm (excluding the dimensions of the positive and negative electrode tabs), and a capacity of 1500 mAh is heat-sealed under the same conditions as the side edge. 100 were produced.

(Example 5)
As shown in FIG. 22, 100 nonaqueous electrolyte batteries were produced in the same manner as described in Example 2 except that the gaps of the recesses 14a to 14c were filled with the filling member 30 made of silicon rubber.

(Example 6)
100 nonaqueous electrolyte batteries were produced in the same manner as described in Example 2 except that the gaps of the recesses 14a to 14c were filled with a filling member made of urethane resin.

(Example 7)
A nonaqueous electrolyte battery having the structure shown in FIG. 23B, a thickness of 4 mm, a width of 75 mm, a length of 105 mm (excluding positive and negative electrode tab dimensions), and a capacity of 1500 mAh was produced in the same manner as in Example 2.

  Moreover, as shown to Fig.23 (a), the NBR filling member 32 which has the projection parts 31a-31c of the shape fitted to the recessed parts 14a-14c was produced. Here, the flat plate portion 33 of the filling member 32 has a rectangular shape with an outside dimension of 65 × 30 mm so that the end portion overlaps the heat fusion portion from which the positive and negative electrode tabs are drawn.

  The protrusions 31a to 31c of the filling member 32 are fitted into the recesses 14a to 14c, and the flat plate portion 33 is disposed so as to cover the heat fusion portion, and these are joined with an adhesive, whereby the structure shown in FIG. 100 non-aqueous electrolyte batteries having the above were manufactured.

(Example 8)
In the non-aqueous electrolyte battery of Example 3, instead of joining the sealing plate and the inner surface of the cup part, the outer dimensions are 3.0 mm × 8.0 mm × 60. A rectangular parallelepiped polyethylene insulator (insulating spacer) of 0 mm was placed, and the insulator and the exterior member were heat-sealed under the same conditions as described in Example 4. 100 non-aqueous electrolyte batteries having such a configuration were prepared. The heat fusion area (one side) between the sealing plate and the insulator and the heat fusion area (one side) between the cup portion and the insulator are the bottom of the cup part located between the electrode group and the short side edge, respectively. It was 18% of the inner area (one side).

Example 9
100 nonaqueous electrolyte batteries were produced in the same manner as described in Example 3 except that the gaps of the recesses 17a to 17d were filled with a filling member made of silicon rubber.

(Example 10)
A nonaqueous electrolyte battery was produced in the same manner as in Example 3.

  Moreover, the NBR filling member which has the projection part of the shape fitted to four recessed parts was produced. Here, the flat plate portion of the filling member has a rectangular shape with an outer dimension of 65 × 30 mm so that the end portion overlaps with the heat fusion portion from which the positive and negative electrode tabs are drawn.

  100 protrusions of the non-aqueous electrolyte battery were produced by fitting the protrusions of the filling member into the recesses and arranging the flat plate portion so as to cover the heat-sealed portion and bonding them with an adhesive.

(Comparative Example 1)
<Formation of exterior member>
An exterior film of the same type as in Example 1 was cut out to a size of 105 × 75 mm as shown in FIG. 25 without drawing, and a rectangular plate-shaped sealing plate 34 was produced. Further, a container 5 having an outer dimension of 105 × 75 mm having the structure shown in FIG.

<Production of electrode group>
An electrode group was produced in the same manner as in Example 1.

<Preparation of non-aqueous electrolyte>
Prepared in the same manner as in Example 1.

<Production of nonaqueous electrolyte battery>
27, except that the heat-sealing portion where the positive and negative electrode tabs extend to the outside, the cup portion facing the space between the electrode groups, and the sealing plate are not heat-sealed inside the battery. 100 non-aqueous electrolyte batteries having the structure shown in FIG. 4, a thickness of 4 mm, a width of 75 mm, a length of 105 mm (excluding positive and negative electrode tab dimensions), and a capacity of 1500 mAh were produced.

(Comparative Example 2)
<Formation of exterior member>
An exterior film of the same type as in Example 1 was cut out to a size of 115 × 75 mm without performing a drawing process to produce a rectangular plate-shaped sealing plate. Further, a container having an outer dimension of 115 × 75 mm was produced in the same manner as in Example 3.

<Production of electrode group>
An electrode group was prepared in the same manner as in Example 3.

<Preparation of non-aqueous electrolyte>
Prepared in the same manner as in Example 1.

<Production of nonaqueous electrolyte battery>
28, except that the heat-sealing portion where the positive and negative electrode tabs extend to the outside, the cup portion facing the space between the electrode groups, and the sealing plate are not heat-sealed inside the battery. 100 non-aqueous electrolyte batteries having the structure shown in FIG. 4, a thickness of 4 mm, a width of 75 mm, a length of 115 mm (excluding positive and negative electrode tab dimensions), and a capacity of 1500 mAh were produced.

(Example 11)
In the nonaqueous electrolyte battery of Comparative Example 1, a protruding portion (outside area size 8.0 × 8.0 mm) protruding inward on the side surface of the cup portion 4 is positioned between the positive electrode tab 11 and the negative electrode tab 13. Formed. The inner surface of the protruding portion was thermally fused to the inner surface of the sealing plate. The area of the heat fusion part was 9% of the area in the bottom part of the cup part located between the electrode group and the short side edge part.

  These fabricated batteries were charged, and the following impact tests were conducted assuming vibration during transportation and indirect force applied after being assembled into a pack by external equipment.

  First, after fixing the battery with a tape so that the side where the positive and negative electrode tabs extend parallel to the center of the vinyl chloride plate having a thickness of 3 mm and an outer dimension of 250 × 150 mm and the short side of the vinyl chloride plate are parallel, A vinyl chloride plate of the same size was placed on the battery, and the opposing vinyl chloride plate periphery was fixed with tape.

Next, in Examples 1, 2, 4 to 7, Comparative Example 1, and Example 11, the case where the positive electrode / negative electrode tab is down is defined as the + direction, and the case where the short side without the tab is defined as the − direction. In Examples 3, 8 to 10 and Comparative Example 2, the case where the positive electrode tab is down is defined as the + direction, and the case where the negative electrode tab is defined as the − direction, the battery fixed to the vinyl chloride plate is placed on the concrete plane. It was dropped 10 times from the + direction and 10 times from the-direction from a height of 100 cm. The number of batteries whose battery voltage changed by 0.1 mV or more after the test is shown in Table 1 below.

  From the result of Table 1, the cup part and sealing plate corresponding to the space part located between the heat-fusion part by which the positive / negative electrode tab is extended outside and the electrode group, and the sealing board were joined in the inside of a battery. It was confirmed that the non-aqueous electrolyte battery had a remarkably small change in battery voltage as compared with the batteries of Comparative Examples 1 and 2, and was found to be effective for external shock resistance.

  Consider the shape of the recess. Comparing Examples 1 and 2, the number of batteries in which the battery voltage changed by 0.1 mV or more was smaller in Example 2, and it is desirable that the shape of the recess be a square column in order to improve impact resistance. Recognize.

  As for the arrangement of the recesses, when Example 2 and 3 are compared, the number of batteries whose battery voltage has changed by 0.1 mV or more is smaller in Example 3. Therefore, in order to improve the impact resistance, the positive electrode tab and the negative electrode tab are arranged so as to face each other by 180 °, and the heat between the heat fusion part from which the positive electrode tab is drawn out and the electrode group and the heat from which the negative electrode tab is drawn out. It is desirable to form a recess between each fused portion and the electrode group.

  In Examples 4 to 7 in which spacers or filling members were used in combination with the formation of the recesses, the number of batteries in which the battery voltage changed by 0.1 mV or more was completely eliminated, and the impact resistance was in Examples 1 and 2. Compared to When the bonding strength between the sealing plate (first surface) and the bottom inner surface (second surface) of the cup portion was compared, Example 4 using an insulating spacer was the highest. In addition, Example 4 was most excellent in terms of the simplicity of the manufacturing method. Furthermore, Examples 4-6 were excellent in the point which does not affect battery thickness. The same tendency was obtained in Examples 8 to 10 in which the positive electrode tab and the negative electrode tab face each other by 180 °.

  On the other hand, in the batteries of Comparative Examples 1 and 2, there were a large number of batteries in which the battery voltage was lowered due to an internal short circuit caused by the deformation of the electrode group and the positive and negative terminals.

  In the embodiment described above, the uncoated portion of the current collector (mixture layer non-formed part) was sandwiched between the folded tabs and these were welded, but the connection method of the current collector and the tab is not limited to this, For example, as shown in FIG. 29, the uncoated portions 6 and 8 of the positive and negative electrode current collectors may be joined together by welding, and the tips of the joined portions may be welded to the tips of the positive and negative electrode tabs 11 and 13.

  In this embodiment, the electrode tab connected to the uncoated portion of the current collector is used as the electrode terminal, but one of the uncoated portions of the current collector is lengthened, and the remaining uncoated It is also possible to weld the portion and draw out the long uncoated portion described above to the outside of the exterior member and use it as an electrode terminal.

  In addition, this invention is not limited to the electrode active material described in the Example. Moreover, although it demonstrated using the nonaqueous solvent secondary battery using the nonaqueous solvent for the nonaqueous electrolyte, it is naturally applicable to the polymer battery using the polymer electrolyte and the solid electrolyte battery using the solid electrolyte. It is also possible to use a polymer thin film or a solid electrolyte membrane instead of the resin separator. Further, it can be applied to a primary battery using a film as an exterior member.

  As described above, according to the present invention, it is possible to provide a non-aqueous electrolyte battery including a film exterior member that has an excellent external impact resistance compared to a conventional battery. Therefore, its industrial value is very large.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

3 is a perspective view schematically showing a sealing plate of an exterior member used in the nonaqueous electrolyte battery of Example 1. FIG. The perspective view which shows typically the container of the exterior member of FIG. FIG. 3 is a plan view schematically showing an electrode group of Example 1. Sectional drawing which showed typically the connection state of the non-application part of the positive electrode collector of Example 1, and a positive electrode tab. The top view which showed typically the state which accommodated the electrode group of FIG. 3 in the container. 1 is a perspective view schematically showing a nonaqueous electrolyte battery of Example 1. FIG. The perspective view which shows typically the sealing board of the exterior member used with the nonaqueous electrolyte battery of Example 2. FIG. The perspective view which shows typically the container of the exterior member of FIG. The perspective view which showed the nonaqueous electrolyte battery of Example 2 typically. 4 is a perspective view schematically showing a sealing plate of an exterior member used in the nonaqueous electrolyte battery of Example 3. FIG. The perspective view which shows typically the container of the exterior member of FIG. FIG. 6 is a plan view schematically showing an electrode group of Example 3. The top view which showed typically the state which accommodated the electrode group of FIG. 12 in the container. The perspective view which showed the nonaqueous electrolyte battery of Example 3 typically. The perspective view which shows typically the sealing board of the exterior member used with the nonaqueous electrolyte battery of Example 4. FIG. The perspective view which shows the container of the exterior member of FIG. 15 typically. FIG. 6 is a perspective view schematically showing an insulating spacer used in Example 4. The perspective view which showed typically the state which accommodated the insulating spacer of FIG. 17 in the container of FIG. FIG. 6 is a plan view schematically showing an electrode group of Example 4. The top view which showed typically the state which accommodated the electrode group of FIG. 19 in the container. The perspective view which showed the nonaqueous electrolyte battery of Example 4 typically. FIG. 6 is a perspective view schematically showing a nonaqueous electrolyte battery of Example 5. FIG. 12 is a partially exploded perspective view of the nonaqueous electrolyte battery according to Example 7. The perspective view which showed the nonaqueous electrolyte battery of Example 7 typically. The perspective view which shows typically the sealing board of the exterior member used with the nonaqueous electrolyte battery of the comparative example 1. FIG. The perspective view which shows typically the container of the exterior member of FIG. The perspective view which showed typically the nonaqueous electrolyte battery of the comparative example 1. FIG. The perspective view which showed typically the nonaqueous electrolyte battery of the comparative example 2. FIG. Sectional drawing which showed typically the another connection method of the non-application part of a positive / negative electrode electrical power collector, and a positive / negative electrode tab.

Explanation of symbols

  1a to 1c, 14a to 14c, 17a to 17d, 27a to 27c ... concave portion, 2, 15, 18, 28 ... sealing plate, 3, 16, 19 ... tapered portion, 4, 20 ... cup portion, 4a to 4d, 20a ˜20d ... edge, 5,21 ... container, 6,22 ... non-applied portion of positive electrode current collector (positive electrode mixture layer non-forming portion), 8,23 ... non-applied portion of negative electrode current collector (negative electrode mixture) (Layer non-formation part), 11, 24 ... positive electrode tab, 12, 26 ... thermoplastic insulating film having metal adhesion, 13, 25 ... negative electrode tab, 29 ... insulating spacer, 30, 32 ... filling member, 31a to 31c ... projection part, 33 ... flat plate part.

Claims (5)

A film-shaped exterior member having a flat shape and bonded to the second surface opposite to the first surface by thermal fusion; an electrode group housed in the exterior member and including a positive electrode, a negative electrode, and a separator; A non-aqueous electrolyte battery comprising a positive electrode terminal electrically connected to the positive electrode and a negative electrode terminal electrically connected to the negative electrode,
The positive electrode terminal and the negative electrode terminal are drawn to the outside from the same heat fusion part of the exterior member or the heat fusion parts opposite to each other,
In the region where the first surface and the second surface are opposed to a space located between the heat fusion part from which at least one of the positive electrode terminal and the negative electrode terminal is drawn out and the electrode group, A nonaqueous electrolyte battery characterized in that inner surfaces are joined to each other.   The joining portion is obtained by joining the inner surface of the concave portion formed on the first surface or the second surface and the inner surface of the remaining surface, and the nonaqueous electrolyte battery has a gap in the concave portion. The nonaqueous electrolyte battery according to claim 1, further comprising a filling member for filling.   The filling member is formed on the flat plate portion fixed on the heat fusion portion from which at least one of the positive electrode terminal and the negative electrode terminal is drawn, and is filled in the gap in the concave portion. The battery according to claim 2, further comprising a protrusion.   The non-aqueous electrolyte battery according to claim 2, wherein the filling member has shock absorption. A film-shaped exterior member having a flat shape and bonded to the second surface opposite to the first surface by thermal fusion; an electrode group housed in the exterior member and including a positive electrode, a negative electrode, and a separator; A non-aqueous electrolyte battery comprising a positive electrode terminal electrically connected to the positive electrode and a negative electrode terminal electrically connected to the negative electrode,
The positive electrode terminal and the negative electrode terminal are drawn to the outside from the same heat fusion part of the exterior member or the heat fusion parts opposite to each other,
In the region where the first surface and the second surface are opposed to a space located between the heat fusion part from which at least one of the positive electrode terminal and the negative electrode terminal is drawn out and the electrode group, A non-aqueous electrolyte battery characterized in that an insulating spacer is interposed.

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