JP6094808B2 - Laminated sealed battery - Google Patents

Description

  The present invention relates to a laminated sealed battery in which a power generation element body is housed in an exterior made of a laminated resin film and sealed in a sealed state.

  With the widespread use of electronic devices such as notebook computers, mobile phones, and digital cameras, the demand for secondary batteries for driving these electronic devices is increasing. In recent years, these electronic devices have been required to increase the capacity of secondary batteries because power consumption has increased with the progress of higher functionality and miniaturization is expected. Among secondary batteries, non-aqueous electrolyte secondary batteries (particularly lithium ion secondary batteries) are used in various electronic devices because of their high capacity.

  The non-aqueous electrolyte secondary battery can be configured by housing a power generation element body in a battery container. Moreover, as a battery container that can reduce the weight of the battery, a method of using a laminated resin film as an exterior material is widely known, and the power generating element body can be stored in a sealed state.

  This laminated resin film is formed by, for example, laminating a resin layer made of a thermoplastic resin on a metal foil in a close contact state. By using the metal foil, the airtightness in the thickness direction of the laminated resin film is secured. Moreover, by laminating the resin layer, it can compensate for various disadvantages of the battery container of the metal foil single layer, and also provides adhesion to the film surface by a method such as heat welding to seal the opening, Airtightness in the surface direction is ensured.

  For example, in a state where the power generation element is disposed in the laminate resin film, the laminate resin film at the periphery thereof is heated in a pressurized state, the resin layer is melted, and the outer edges of the overlapped films are welded together and sealed. Thus, a laminated sealed battery containing the power generation element body is manufactured.

  In some cases, a plurality of laminated sealed batteries are used as an assembled battery by stacking a plurality of the batteries. At this time, each laminated sealed battery is housed in a metal casing, and space efficiency and rigidity as an assembled battery are ensured.

  By the way, in the lithium ion secondary battery which is a typical non-aqueous electrolyte secondary battery, there is a problem that battery performance deteriorates when moisture enters the inside of the battery. For example, when the metal in the laminated resin film that covers the battery is an aluminum foil, the aluminum is corroded (electrolytic) when the aluminum foil comes into contact with external water in a state where it is in contact with the metal casing of the assembled battery. A phenomenon can occur.

  In addition, there may be a manufacturing process in which the outer edge of the exterior is cut and molded after welding so as to form a predetermined outer shape, and the aluminum foil in the laminated resin film is unavoidable on the end surface of the film outer edge. Will be exposed to the outside. Moreover, the end surface of the outer edge of the film is easily in contact with a metal housing due to the structure of the assembled battery. If this portion of the aluminum foil is corroded, the hermeticity of the exterior deteriorates in accordance with the loss of the aluminum foil layer, and moisture (water vapor) can easily enter the interior of the exterior. Then, intrusion moisture reacts with the electrolyte to generate, for example, hydrofluoric acid, and the generated hydrofluoric acid corrodes members such as an electrode that is a power generation element body, and the battery performance is further deteriorated.

  Furthermore, the battery may generate heat due to overcharge or internal short circuit, resulting in abnormal temperature rise or leaving it at a high temperature. In such a case, when gas is generated inside the battery of the sealed battery and the pressure inside the exterior rises, the weld strength of the outer edge is impaired due to the loss of the aluminum foil layer. It is spurred to peel off the laminated resin film welded surface. There was a problem that liquid leakage could occur in the worst case due to airtight leakage of the battery.

  With respect to this problem, Patent Document 1 describes a technique for covering the end surface of the outer edge of the film on the long side with a protective member in order to prevent damage to the laminated resin film that is the exterior of the laminated sealed battery. Yes. Specifically, in a state where the outer edge edge to which the adhesive is applied or the double-sided tape is adhered is folded and attached to the outer surface of the exterior film, or the end face of the outer edge edge is covered with a U-shaped socket. Similarly, there is disclosed a method of pasting or bending the outer edge part twice so that the end face is not exposed to the outside. According to this method, since the welded portion of the outer edge is fixed in a bent state, the end surface of the outer edge can be protected so as not to contact the metal casing.

JP 2007-335309 A

  However, by protecting the end face of the outer edge, the corrosion of the aluminum foil in the laminated resin film can be suppressed, the infiltration of moisture can be prevented, the battery performance can be maintained, and the durability can be improved. The operation | work which provides a member is needed. In particular, in fixing using a double-sided tape or an adhesive, the protective member may be peeled off in a high-temperature and high-humidity environment, and is not suitable for an on-vehicle environment, for example.

  The present invention has been made in view of such circumstances, and can improve the reliability of the battery by reliably covering the outer edge portion of the laminate resin film while simplifying the workability at the time of manufacture. An object is to provide a laminated sealed battery.

The laminated sealed battery of the present invention for solving the above problems comprises a power generating element having a positive electrode and a negative electrode, and a laminated resin film obtained by laminating a metal foil with a thermoplastic resin, and the linear outer end of the laminated resin film. In a laminated sealed battery including an exterior housing the power generation element body by sealing the edges of the power generation element body by sealing the edges together in a rectangular shape along the outer edge, and on the welding surface of the outer edge of the exterior, A metal foil member comprising a metal foil layer having a metal adhesive property and having an adhesive low melting point resin layer whose melting point is lower than that of the thermoplastic resin film is covered with at least one surface is further inserted. An outer end surface covering portion that covers the end surface of the outer end edge of the exterior, which is formed from a resin of the resin layer, is provided .

  According to this structure, the coating | cover which consists of resin of an adhesive low melting point resin layer and protects the end surface of an outer end edge part can be formed in the end surface of the outer end edge part of an exterior. This coating prevents the metal foil from corroding starting from the outer edge of the laminated resin film. Therefore, the reliability of the laminated sealed battery can be increased.

  More specifically, at the time of welding, the adhesive low-melting-point resin on the surface of the metal foil member inserted into the welding surface of the outer edge of the exterior flows before the thermoplastic resin of the laminate resin film. At that time, the flow direction of the metal foil layer of the metal foil member is well regulated so that the molten resin of the adhesive low melting point resin layer protrudes from the welding surface. Further, after the metal foil member is set in advance on the surface to be welded, the above-described coating can be formed by a simple method which simply performs the same operation as the welding process of a normal laminate resin film.

  Moreover, since the adhesive strength between the thermoplastic resins of the laminate resin film and the adhesive low melting point resin layer is ensured, and the adhesive low melting point resin layer adheres well to the metal foil layer, the outer edge of the laminate resin film The welding strength is ensured sufficiently large.

It is the perspective view of the lithium ion secondary battery which concerns on 1st Embodiment, Comprising: It is the figure which fractured | ruptured the vicinity of a positive electrode partially. Similarly, about each member which comprises a lithium ion secondary battery, it is the schematic which shows the planar arrangement | positioning before folding an outer edge part. It is the III-III sectional view taken on the line of FIG. It is the schematic which shows the planar arrangement | positioning about each member similarly to FIG. 2 about the battery of 2nd Embodiment. It is a figure equivalent to the III-III line section of Drawing 1 about the battery of a 2nd embodiment. It is a figure equivalent to the III-III line cross section of FIG. 1 about the battery of the modification of 2nd Embodiment. It is the schematic which shows the planar arrangement | positioning about each member similarly to FIG. 2 about the battery of 3rd Embodiment. It is the VIII-VIII sectional view taken on the line of FIG. 1 about the battery of 3rd Embodiment. It is a figure equivalent to the III-III line cross section of FIG. 1 about the battery of the 1st modification. It is a figure equivalent to the III-III line cross section of FIG. 1 about the battery of the 2nd modification. It is a figure equivalent to the III-III line cross section of FIG. 1 about the battery of the 3rd modification.

[First embodiment]
Hereinafter, Embodiment 1 in which a laminated sealed battery of the present invention is applied to a lithium ion secondary battery (hereinafter also simply referred to as a battery B) will be described with reference to FIGS.

  As shown in FIG. 1, the battery B of the present embodiment includes a laminated electrode body 11 and a non-aqueous electrolyte (not shown) constituting the power generation element body in an exterior 20 made of laminated resin films 21 and 22. It is housed in a container. In FIG. 1, the symbol V indicates the vertical direction, L indicates the longitudinal direction, and S indicates the short direction.

The electrode body 11 includes a positive electrode plate 11a and a negative electrode plate 11c, and is formed by laminating a predetermined number of substantially square positive electrode plates 11a and negative electrode plates 11c alternately via separators (not shown). It has the whole shape. A positive electrode terminal 12 and a negative electrode terminal 13 are respectively connected to the positive electrode plate 11a and the negative electrode plate 11c by a predetermined method, and the positive electrode terminal 12 and the negative electrode terminal 13 are a pair of short outer edges facing each other of the exterior 20. Derived from the parts E ₀ a and E ₀ c to the outside in opposite directions. The battery B is used by being connected to an external device via the positive electrode terminal 12 and the negative electrode terminal 13 and appropriately charging and discharging.

  The positive electrode plate 11a includes a positive electrode mixture layer containing a positive electrode active material capable of occluding and releasing lithium ions on both surfaces of a positive electrode current collector formed of a metal such as aluminum. A positive electrode terminal 12 made of metal is welded. The negative electrode plate 11c includes a negative electrode mixture layer containing a negative electrode active material capable of occluding and releasing lithium ions on both sides of a negative electrode current collector formed of a metal such as copper. The negative electrode terminal 13 made of copper is welded.

The exterior 20 is formed by superimposing two laminated resin films 21 and 22 having a substantially rectangular shape in the vertical direction and welding the outer edges 212 and 222 along the four sides of the rectangle. At the center of the upper laminate resin film 21, a square-shaped convex portion 211 that can accommodate the electrode body 11 protrudes upward and is embossed. The four outer end edges 212 on the periphery of the convex portion 211 are each formed in a long rectangular shape corresponding to four sides of the rectangle, and each has a flat flange shape. The lower surface of the outer edge 212 and the upper surface of the outer edge 222 of the lower laminated resin film 22 overlapping the lower surface are thermally welded, and the opening between the two laminated resin films 21 and 22 is sealed. outer edges E ₀ of the exterior 20 is formed Te. The outer edge E ₀ is formed in a long rectangular shape in the same manner on the four sides of the convex portion 211 corresponding to the shape of the outer edge 212 of the upper laminated resin film 21 before welding. Has a flat flange shape.

Further, the welding surfaces E ₀ w has a region corresponding to the long rectangular four sides of the outer edge portion E _0, of the outer edge portion E ₀ of the four sides, opposite long sides The metal foil members 231 are inserted into the welding surfaces E ₀ w of the pair of long outer edge portions E ₀ long. The body portion of the metal foil member 231 that is inserted into the welding surface E ₀ w on the long side are formed two sides of a longitudinal outer edge portion E ₀ long weld surfaces E ₀ w to approximately similar small elongated rectangular . Further, the main body portion of the metal foil member 231 is inserted so that the outer end face 23me of the metal foil layer 23m is flush with the end face E ₀ e of the longitudinal outer end edge E ₀ long.

Further, as will be described later, the end surface E ₀ e of the longitudinal outer end edge E ₀ long is melted by the resin forming the low melting point resin layer 23 a of the metal foil member 231 and flows out from the end surface E ₀ e to the outside. It is covered with the outer end face covering portion 23ae formed as a result of solidification in a state of covering E ₀ e. The outer end surface covering portion 23ae is a portion that protects the end surfaces of the metal aluminum layers 21b and 22b of the laminated resin films 21 and 22 from being exposed to the outside of the exterior 20.

Then, the two long outer end edge portions E ₀ long are folded upward so as to follow the rising side surface 211a of the convex portion 211 after the outer end edge portion E ₀ is formed. As a result, a two-side folded shape holding edge E ₁ is formed at the opposing edge on the long side of the exterior 20. At this time, the main body portion of the outer edge portion E ₀ long the welding surface E ₀ metallic foil is inserted into the w member 231 be folded together with the outer edge portion E ₀ long, the metal foil member 231 in the longitudinal direction A bent portion 23b ₁ is formed along the line.

Of the four outer end edges E ₀ , the pair of short outer end edges E ₀ a, E ₀ c facing each other on the short side is one short outer edge E ₀ a. A positive terminal 12 is led out between the upper and lower laminated resin films 21 and 22 in the center, and a negative lead terminal 23c ₁ is drawn from the right side of the positive terminal 12 in FIG. The negative electrode lead terminal 23c ₁ is a short of one side of the main body of the metal foil member 231 on the right side of the metal foil member 231 on the right side of the two sides of the metal foil member 231 inserted into the long outer edge E ₀ long of the two sides. It is formed to extend to the hand outer edge E ₀ a. A negative electrode terminal 13 is led out between the upper and lower laminated resin films 21 and 22 at the center of the short outer edge E ₀ c on the other side.

The negative electrode lead terminal 23c ₁ is formed by bending the main body of the metal foil member 231 by 90 ° inward in the short direction so as to follow the welding surface E ₀ w of the short outer edge portion E ₀ a on one side. It is drawn out of the exterior 20 in a shape that is bent 90 ° outward in the longitudinal direction so as not to come into contact with 12. Further, the weld edges 23c ₂ of the other side, the welding surface E ₀ is 90 ° bent lateral direction inwardly along the body portion in the lateral outer edges E ₀ c of the other side of the metal foil member 231 It is welded to the negative electrode terminal 13 in w. Negative electrode lead terminal 23c ₁ connected via the other side of the weld edges 23c ₂ and the negative terminal 13, whereas drawn as described above in the short outer edge portion E ₀ a side, the positive and negative with the positive terminal 12 This is a portion that serves as a terminal for detecting an inter-voltage, and is connected to an external ECU.

Incidentally, the short outer edge portion E ₀ a of the exterior 20, in each of the welding surface E ₀ w of E ₀ c, the positive terminal 12, negative terminal 13, and a portion of the welded end edges 23c ₂ is in the vertical direction Each is sandwiched between tab films 12a and 13a. The tab films 12a and 13a are films that are inserted to ensure insulation between each metal terminal and the aluminum layer of the laminated resin film.

  Further, as shown in FIG. 3, the upper and lower laminated resin films 21 and 22 are formed by outermost film layers 21a and 22a and aluminum obtained by laminating the film layers 21a and 22a by a predetermined method. It has a three-layer structure in which aluminum layers 21b and 22b made of foil and welding layers 21c and 22c formed inside the aluminum layers 21b and 22b are sequentially laminated. Polyethylene terephthalate, nylon or the like can be used as the material of the film layers 21a and 22a, and polypropylene or the like can be used as the material of the welding layers 21c and 22c.

  The metal foil member 231 has a three-layer structure in which a low-melting point resin layer 23a is laminated on both surfaces of a metal foil layer 23m made of a stainless steel metal foil.

The metal foil layer 23m has a rigidity capable of maintaining its own shape while being foil-shaped. Therefore, the folded shape of the folded shape holding edge E ₁ can be held by folding together with the outer edge E ₀ long on the long side. When the outer edge consisting of only two layers of films without the metal foil member 231 inserted is folded back, it may be restored to its original flat shape if left in a natural state after removing the folded external force. Once folded shape bending deformation metal foil layer 23m retains its shape to resist this restoring force, it is possible to support the folded shape retaining edge E _1.

  Moreover, as a material of the low melting point resin layer 23a, the melting point is lower (molding temperature is 200 ° C. or less) than the resin such as polypropylene forming the weld layers 21c and 22c of the laminate resin films 21 and 22, and the metal foil layer Resins with high adhesion to 23 m and polypropylene can be used. More specifically, an acid-modified polyolefin and a low melting point acrylic resin can be suitably used. Particularly preferably, as the acid-modified polyolefin, trade name “Toyotac” (maleic anhydride-modified polypropylene), which is a hot melt adhesive for polyolefins manufactured by TOYOBO, can be used. Moreover, typically, a polymethyl methacrylate resin can be preferably used as the low melting point acrylic resin.

  The battery B of this embodiment can be manufactured, for example, by the following method.

  A plurality of predetermined positive electrode plates 11a and negative electrode plates 11c manufactured by a predetermined method are alternately stacked with a separator interposed therebetween. The positive and negative electrode terminals 12 and 13 are welded to the positive and negative electrode plates 11a and 11c. Moreover, in order to ensure insulation from the periphery, the outermost periphery of the electrode body 11 is wound with a separator.

  Separately, the above laminate resin film is prepared. The laminated resin film has a thickness of 150 to 200 μm per sheet. The laminate resin film is cut into a predetermined size, and a convex portion 211 for housing the electrode body 11 is press-molded.

  Separately, a metal foil member 231 is prepared. Specifically, an acid-modified polyolefin resin layer or a polymethyl methacrylate resin layer is laminated on both surfaces of a stainless steel metal foil having a thickness of about 10 μm. In either a pellet form or a sheet form, it can be suitably laminated under heating by suitably applying and sticking. The thickness of the low melting point resin layer 23a can be set to 20 to 50 μm. The stainless steel foil laminated with this resin layer is cut into the shape of the metal foil member 231 described above.

And said electrode body 11 is accommodated inside the convex part 211 of the upper side laminated resin film 21. FIG. Each of the positive electrode terminal 12 and the negative electrode terminal 13 is accommodated in a state of protruding from the outer edge 212 of the film. Further, the welded edge portion of the metal foil member 231 is arranged so that the main body portion of the bent metal foil member 231 is disposed on one side of the two sides on the long side of the outer edge 212 of the film that is the surface to be welded. 23c ₂ is welded to the negative electrode terminal 13, and the negative electrode lead terminal 23c ₁ is pulled out from the outer edge. In addition, a straight metal foil member 231 having only a main body is disposed on the other side of the long side.

  Further, the lower laminate resin film 22 is overlaid from above the upper laminate resin film 21 containing the electrode body 11. At this time, the metal foil member 231 is inserted between the two outer end edges 212 and 222 on the long side, and the low melting point resin layer 23a and the welding layers 21c and 22c, or the welding layers 21c and 22c are connected to each other. The lower laminated resin film 22 is overlaid in the opposed state.

  Inject a separately prepared electrolyte.

In a state where the electrolytic solution is injected, the outer edges of the laminated laminate resin films are welded and sealed. At the start of the welding operation for heating under pressure, the metal foil member 231 is used even at a low temperature where the film is not yet melted below the melting point of the thermoplastic resin of the laminated resin films 21 and 22 (resin of the welding layers 21c and 22c). The resin of the low melting point resin layer 23a is melted first. Then, the melted resin of the liquefied low melting point resin layer 23a uses the surface of the metal foil layer 23m as a guide surface in the flow direction, and the outer edge E of the exterior along the welded (planned) surface E ₀ w of the laminated resin film. It flows smoothly in the outer direction of ₀ , and further easily protrudes from the welding surface E ₀ w to the outside of the exterior 20 to cover the end surface E ₀ e.

  Thereafter, as the temperature rises to the welding temperature of the original welded layers 21c and 22c, the welded layers 22c and 22c made of the thermoplastic resin of the laminated resin film are melted, and the welded layers 21c and 22c of the laminated resin film are melted together. Alternatively, the molten resin between the welded layers 21c and 22c of the laminated resin film and the low melting point resin layer 23a of the metal foil member 231 is fused and welded at the respective boundary surfaces.

After returning to room temperature after the welding operation, the outer edge E ₀ of the exterior is welded and sealed in a state where the metal foil member 231 is inserted into the welding surface E ₀ w on the long side. Further, on the end face E ₀ e of the outer edge, the outer end face made of a resin of low melting point resin layer 23a which solidified end face E ₀ e in covered intact protrudes from the outer edge portion E ₀ long the outer coating A portion 23ae is formed. The outer end surface covering portion 23ae is moved to the smooth end surface E ₀ e molten resin along the surface of the metal foil layer 23m, since it is formed as a result of protruding, well it covers the scab-like end face E ₀ e entire surface.

After welding, the outer end edge E ₀ long of the laminated resin film is folded back along the rising side surface 211a of the convex portion 211 to form the folded shape holding edge E ₁ .

  An initial charge / discharge treatment is performed to manufacture a lithium ion secondary battery which is one embodiment of the laminated sealed battery of the present invention.

Even if the folded shape holding edge E ₁ of the outer end edge E ₀ of the exterior 20 comes into contact with the metal casing C, moisture, salt, etc., the end face E ₀ e is protected by the outer end face covering portion 23ae. The conductive phenomenon through the aluminum layers 21b and 22b in the laminate resin film does not occur. Corrosion of the aluminum metal foil is suppressed, the welding strength of the folded shape holding edge E ₁ is maintained, the durability of the exterior is increased, and the reliability of the battery B is increased.

As is clear from the above detailed description, the laminated sealed battery B according to the first embodiment includes a power generation element body having a positive electrode plate 11a and a negative electrode plate 11c, and welded layers 21c and 22c made of a thermoplastic resin. The laminated resin films 21 and 22 are laminated with the aluminum layers 21b and 22b, and the linear outer end edges 212 and 222 of the laminated resin film are welded to each other in a rectangular shape along the outer end edges. A metal bonding having a metal adhesion and a lower melting point than the thermoplastic resin film, on the welding surface E ₀ w of the outer edge of the outer packaging. A metal foil member 231 provided with a metal foil layer 23m whose both surfaces are covered with a low melting point resin layer 23a having a property is inserted.

According to this arrangement, the end face E ₀ e of the outer edge of the exterior, made of resin having a low melting point resin layer 23a having a metallic adhesion, the outer end surface covering portion 23ae of protecting the end face E ₀ e of the outer edge Can be formed. The outer end surface covering portion 23ae prevents the aluminum layers 21b and 22b from corroding starting from the outer end edge portion E ₀ long (E ₁ ) made of a laminate resin film. Therefore, the reliability of the laminated sealed battery B can be increased.

More specifically, at the time of welding, the resin of the low melting point resin layer 23a on the surface of the metal foil member 231 inserted into the planned welding surfaces of the outer edges 212 and 222 of the laminated resin films 21 and 22 is the heat of the laminated resin film. It flows before the plastic resin. At that time, the metal foil layer 23m of the metal foil member 231 well regulates the flow direction so that the molten resin of the low melting point resin layer 23a protrudes from the welding surface E ₀ w. In addition, after the metal foil member 231 is set in advance on the surface to be welded, the outer end surface covering portion 23ae can be formed by a simple method simply by performing the same operation as in the ordinary laminating resin film welding step.

Further, the adhesive strength between the thermoplastic resins of the laminated resin films 21 and 22 and the low melting point resin layer 23a is ensured, and the low melting point resin layer 23a adheres well to the metal foil layer 23m. The welding strength of the edge E ₀ long (E ₁ ) is ensured sufficiently high.

The exterior 20 has an upper laminate resin film 21 embossed with a convex portion 211 along the periphery of the rectangular shape for housing the power generation element body, and an outer edge 212 of the lower laminate resin film 22. , 222 are welded to each other, and the outer end edge portion (folded shape holding edge portion E ₁ ) of the exterior is folded back so as to follow the rising surface 211a of the convex portion 211. The foil layer 23m has rigidity capable of maintaining its own shape, and the outer end edge portion of the exterior is formed by being folded back together with the outer end edge of the metal foil member 231 inserted into the welding surface E ₀ w. It is characterized by being.

According to this configuration, since only the laminated resin film 21 on one side has the exterior having the embossed convex portion 211, the power generating element body of the same shape is accommodated to ensure the same welding area at the outer edge of the exterior Under the conditions of sealing, the overall shape of the exterior can be reduced compared to an exterior or the like in which the outer end edge is simply folded back along the side surface of the electrode body without the convex portion being formed. This is advantageous from the viewpoint of securing the capacity per volume of B. Further, a metal foil member 231 having a stainless steel metal foil layer 23m having rigidity capable of holding its own shape is inserted on the welding surface E ₀ w of the outer edge, and together with the laminate resin film on the outer edge. Since the outer edge portion of the metal foil layer 23m is also folded, the bent portion 23b ₁ formed as a result has the effect of holding the folded shape of the folded shape holding edge E ₁ .

More specifically, even when an external force such as vibration or pressure is applied during use of the battery, the folded shape of the folded shape holding edge E ₁ (outer edge) is maintained, so that the durability of the battery is improved. It can be improved. Further, even when gas is generated inside the battery and pressurized from the inside, the bent shape is similarly maintained, so that the durability of the battery can be improved.

The positive electrode terminal 12 and the negative electrode terminal 13 is derived exterior outer edges opposing pair of short-side outer edge portion E ₀ a of E _0, the E ₀ c to the outside, respectively, the metal foil layer 23m is The welded edge 23c ₂ at one end of the metal foil member 231 is made of conductive stainless steel, and the negative electrode terminal 13 is on the welding surface E ₀ w of one short outer edge E ₀ c from which the negative electrode terminal 13 is led out. The metal foil member 231 has a negative electrode lead terminal portion 23c ₁ that is extended from the other short outer end edge portion E ₀ a by extending the other end of the metal foil member 231 to the outside. To do.

According to this configuration, in one cell-like battery B, the positive electrode terminal 12 and the negative electrode terminal 13 are respectively opposite to each other from the short outer edge portions E ₀ a and E ₀ c on the opposite sides of the exterior. Even in the case of being led out, the positive electrode terminal 12 and the negative electrode lead terminal 23c ₁ connected to the negative electrode terminal 13 through the welded edge portion 23c ₂ are connected to the short outer edge portion E on the same side. ₀ Can be pulled out in the same direction from a. Therefore, when this cell battery is assembled into an assembled battery, there is an effect that the wiring with the ECU for voltage detection of each cell battery can be easily performed.

  The thickness of the metal foil layer 23m is 10 μm to 500 μm.

According to this configuration, the metal foil layer 23m is formed of a general-purpose metal foil material having a thickness in the range of 10 μm to 500 μm, so that the rigidity of the outer edge E ₀ long (E ₁ ) of the exterior 20 is appropriately set. Can be kept in range.

That is, if the thickness of the metal foil layer 23m is smaller than 10 μm, the metal foil member 231 has insufficient rigidity and cannot hold the folded shape holding edge portion E _{1 in} a folded state, and the effect of improving durability may be insufficient. If it is larger than 500 μm, the rigidity of the outer edge E ₀ long becomes too large, and the work efficiency of the folding process may be impaired. The thickness of the stainless steel metal foil layer 23m is particularly preferably about 10 μm.

  Further, the metal foil layer 23m is characterized by containing as a main component any one of aluminum, stainless steel, and copper.

  According to this configuration, any metal material such as aluminum, stainless steel, and copper has an appropriate rigidity, and can maintain its own shape even with a thickness as thin as possible within a range in which the compactness of the entire exterior 20 can be maintained. In addition, any metal material has an appropriately low electrical resistivity, so that the resistance at both ends of the thin metal layer can be easily reduced, and the energy loss of the battery can be suppressed.

  The low melting point resin layer 23a having metal adhesion is characterized by using as a raw material either an acid-modified polyolefin resin or a low melting point acrylic resin.

Since the acid-modified polyolefin resin or the low melting point acrylic resin has metal adhesiveness, it can be favorably bonded to the metal material of the metal foil layer 23m. Therefore, it is possible to sufficiently secure the welding strength of the welding surface E ₀ w. Further, since the acid-modified polyolefin resin or the low-melting point acrylic resin melts before the thermoplastic resin of the weld layers 21c and 22c of the laminate resin film, it can flow between the weld (planned) surfaces E ₀ w quickly at the time of welding. Therefore, the outer end surface covering portion 23ae can be formed satisfactorily.

  The surface of the metal foil layer 23m is characterized by being chromated.

  According to this configuration, the corrosion resistance of the surface of the metal foil layer 23m can be increased.

Specifically, when hydrofluoric acid is generated inside a sealed battery in a lithium ion secondary battery, the metal foil layer 23m inserted in the welding surface E ₀ w is prevented from being corroded, and the welding strength is increased. Can be maintained.

[Modification of First Embodiment]
In the first embodiment described above, the low melting point resin layer 23a of the metal foil member 231 has a three-layer structure in which both sides of the metal foil layer 23m are laminated. However, the present invention is not limited to this configuration. It may have a two-layer structure in which the low melting point resin layer 23a is laminated on one side. Even when the low-melting point resin layer 23a is laminated only on one side of the metal foil layer 23m, the outer end face coating that covers the end face E ₀ e by causing the molten resin of the low-melting point resin layer 23a to flow out from the outer end edge portion. The portion 23ae can be formed.

Moreover, although the example of the one-side embossing exterior | packing which only the upper laminate resin film 21 has the convex part 211 was shown, it is not restricted to this structure. Even exterior sides embossing, can be held folded shape of the folded shape retaining edge E ₁ to ensure the durability while keeping the size of the exterior.

Also, although the configuration of forming the negative electrode lead terminal 23c ₁ by extending the body portion of one side of the metal foil member 231 of one of the outer edges of the two sides of the long side, the other metal foil The main body portion of the member 231 may be extended to similarly form the positive electrode lead terminal. Further, the metal foil members 231 and 231 on both sides may be extended in opposite directions to form a positive electrode lead terminal and a negative electrode lead terminal. In any configuration, when an assembled battery is formed, wiring with the ECU for voltage detection of each cell battery can be easily performed.

[Second Embodiment]
Next, the battery B2 of the second embodiment will be described mainly with respect to a configuration different from the first embodiment. As in the first embodiment, the battery B2 according to the second embodiment is obtained by storing the laminated electrode body 11 and the non-aqueous electrolyte in an exterior 20 made of laminated resin films 21 and 22. The configuration of the metal foil member 232 is different from that of the first embodiment. In the following description of each embodiment and modification different from the first embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

The metal foil member 232 of the second embodiment is inserted into the welding surface E ₀ w so as to continuously cover the inner surface 211b of the convex curved portion 211c that forms the convex portion 211 of the upper laminate resin film 21. That is, as shown in FIGS. 4 and 5, the main body portion of the metal foil member 232 is formed wide enough to partially cover the inner surface of the convex portion 211 disposed on the inner side of the film with respect to the welding surface E ₀ w. .

Similarly to the first embodiment, two metal foil members 232 are inserted along the long outer edge E ₀ long of the two sides on the long side, and the metal foil layer 23m in the main body of the metal foil member 232 The outer end face 23me is inserted in alignment with the end face E ₀ e of the outer end edge E ₀ long. After the welding, the outer edge E ₀ long is folded back as in the first embodiment, and the metal foil member 232 is formed with a bent portion 23b ₁ .

Further, the inner end face 23mi of the main body portion of the metal foil member 232 is arranged on the inner side in the short side direction than the convex curved portion 211c of the convex portion 211. That is, the portion of the metal foil member 232 disposed on the inner side in the short direction from the welding surface E ₀ w is closely attached so as to cover the inner surface of the convex portion 211, and the inner side surface that is the back surface of the rising side surface 211a of the convex portion 211, And it is bent together with the upper laminate resin film 21 so as to follow the bottom surface of the convex portion 211. The metal foil member 232 is formed with a second bent portion 23b ₂ bent along the convex portion 211c at an angle formed by the bottom surface and the inner surface, and an angle formed by the inner surface and the welding surface E ₀ w. A third bent portion 23b ₃ bent along the concave bent portion 211d is formed.

As is clear from the above description, in the laminated sealed battery B2 of the second embodiment, the metal foil member 232 continuously covers the inner surface 211b of the convex curved portion 211c that forms the convex portion 211. It is characterized in that it is formed so as to be connected to the portion of the metal foil member inserted into the welding surface E ₀ w.

According to this arrangement, the portion of the metal foil member 232 that covers the inner surface 211b of the convex curved portion 211c of the convex portion 211, the second bent portion 23b along the convexly curved portion 211c ₂ are formed. In addition, the portion covering the inner surface 211b of the convex portion 211c of the metal foil member 232 and the portion inserted into the welding surface E ₀ w are continuously connected to each other, and the metal foil member 232 includes Then, a third bent portion 23b ₃ is formed that is bent at an angle formed by the convex portion 211 and the welding surface E ₀ w. Therefore, since the metal foil layer 23m in the metal foil member 232 has rigidity to maintain its own shape, the bent shape of the convex bent portion 211c and the _second bent portion 23b ₂ and the third bent portion 23b ₃ There is an effect that the bent shape of the inner end portion of the welding surface E ₀ w can be maintained.

More specifically, when gas is generated inside the battery, the internal pressure of the battery at the convex part 211c of the convex part 211 or the inner end part of the welding surface E ₀ w, which is a bent part of the laminate resin film, is determined. Ascending causes stress intensively and increases the possibility of damage. Here, the rigidity of the bent shape in which the metal foil member 232 is inserted or closely adhered is sufficiently maintained, and it is possible to suppress the occurrence of damage by increasing the resistance to stress, and the durability of the exterior is improved. Can be made.

[Modification of Second Embodiment]
In the second embodiment described above, in one form of the metal foil member 232, bent portions 23b ₁ and the second bent portion 23b2 and the third bent portion 23b _3, a configuration has been shown in which it is formed bent portions 23b ₁ and the second bent portion 23b ₂ may be formed by separate metal foil members 231 and 233, respectively.

That is, as shown in FIG. 6, the folded shape holding edge E ₁ is covered with a low melting point resin layer 23 a inserted into the welding surface E ₀ w and has a rigidity capable of holding its own shape. The convex curved portion 211c forming the convex portion 211 is folded back together with the metal foil member 231 having 23m, and the rigidity is such that at least one surface is covered with the low melting point resin layer 23a and the shape of the convex curved portion 211c can be maintained. The inner surface 211b can be covered with another metal foil member 233 provided with another metal foil layer 23m having the following.

According to this configuration, similarly to the first embodiment, the shape of the folded shape holding edge portion E ₁ formed by folding the outer end edge portion E ₀ long by inserting the metal foil member 231 in a folded shape. Since the inner surface 211b of the convex curved portion 211c is covered with another metal foil member 233, the rigidity of the bent shape of the convex portion 211 can be increased. Therefore, durability of the exterior 20 can be improved.

[Third Embodiment]
Next, the battery B3 of the third embodiment will be described mainly with respect to a configuration different from the first and second embodiments. The battery B3 according to the third embodiment is different from the first embodiment in the configuration of the metal foil member 234.

  The metal foil member 234 of the third embodiment is laminated on the laminate resin film 21 so as to cover the entire inner surface 213 of the upper laminate resin film 21 that is embossed. That is, as shown in FIGS. 7 and 8, as in the first embodiment, a single three-layered metal foil member 234 having low-melting point resin layers 23a on both surfaces of the metal foil layer 23m is also composed of three layers. It is laminated inside the laminate resin film 21 on the upper side of the structure. That is, the laminate resin film 21 has a six-layer laminated structure of a film layer 21a, an aluminum layer 21b, a welding layer 21c, a low melting point resin layer 23a, a metal foil layer 23m, and a low melting point resin layer 23a in order from the outside. For example, a metal foil member 234 embossed in the same shape as the upper laminate resin film 21 in advance can be laminated on the entire inner surface 213 of the laminate resin film 21.

In addition, an insulating member 234a ₂ is provided by a predetermined method in a portion of the short outer edge 234a on the short side of the metal foil member 234 that overlaps the positive electrode terminal 12 when the electrode body 11 is stored. Insulation with the positive electrode terminal 12 is ensured. In other widthwise outer end edge 234c of the metal foil member 234, the portion overlapping the negative electrode terminal 13, the welding portion 234c ₂ of the negative terminal 13 in a predetermined manner is formed. Then, negative electrode lead terminal 234c ₁ is a widthwise portion arranged in a direction right of the positive electrode terminal 12 in the widthwise outer end edges 234a, is extended to outside the small rectangle from the shorter outer edges E ₀ a Is formed. As a result, the negative electrode lead terminal 234c ₁ connected to the negative electrode terminal 13 through the welded portion 234c ₂ is pulled out as described above at the short outer end edge E ₀ a on one side, and the positive / negative voltage together with the positive electrode terminal 12 This is a detection terminal.

  As apparent from the above description, in the laminated sealed battery B3 of the third embodiment, the metal foil member 234 covers the entire inner surface 213 of the embossed upper laminated resin film 21 so that the laminated resin film 21 is covered. It is characterized by overlapping.

  According to this configuration, the metal foil member 234 is laminated on the entire inner surface 213 of the upper laminate resin film 21, so that the rigidity of the upper laminate resin film 21 on which the convex portions 211 are embossed is ensured to be the largest, Durability can be improved better over the entire exterior 20.

  Moreover, in order to insert the outer edge part of the metal foil member 234 into the welding surface, the work of arranging the metal foil member 234 with respect to the laminate resin films 21 and 22 can be performed more easily.

Specifically, a process of aligning and superimposing the same shape of the metal foil member 234 on the upper laminate resin film 21, and in this state, the outer edges 212, 222 of the laminate resin films 21, 22 are connected to each other. Through the welding step, the outer end edge of the metal foil member 234 can be inserted into the outer end edge E ₀ of the exterior 20. That is, in other embodiments, the outer edge is subjected to a troublesome work step of disposing the main body portions of the two metal foil members on the two long sides of the outer edge 212 of the laminated resin film 21, respectively. Although 212 and 222 are welded together, it is not necessary in this embodiment.

Further, the positive electrode terminal 12 and the negative electrode terminal 13 are respectively led out from the pair of short outer edge portions E ₀ a and E ₀ c among the outer edge of the exterior, and the metal foil layer 23m is made of a conductive metal, the other widthwise outer end edge 234c of the metal foil member 234 is connected to the other short-side outer edge portion E ₀ c of the welding surface E ₀ through a weld 234c ₂ in w negative terminal 13 of the negative terminal 13 The metal foil member 234 electrically insulates one short outer end edge portion 234a from the positive electrode terminal 12 at one short outer end edge portion E ₀ a and one short outer end edge portion. It has a negative electrode lead terminal 234c _{1 from} which 234a is drawn out and extended.

According to this configuration, in one cell-like battery B3, the positive electrode terminal 12 and the negative electrode terminal 13 are opposite to each other from the short outer edge portions E ₀ a and E ₀ c on the opposite sides of the exterior. Even in the case of projecting toward the same direction, the positive electrode terminal 12 and the negative electrode lead terminal 234c ₁ connected to the negative electrode terminal 13 are directed in the same direction from the short outer edge E ₀ a of the same side. Can be pulled out. Therefore, when this cell battery B3 is assembled into an assembled battery, there is an effect that the wiring with the ECU for voltage detection of each cell battery B3 can be easily performed.

  The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[First Modification]
In each of the above-described embodiments, the outer end edge portion of the exterior has been shown to be configured to be folded back together with the outer end edge portion of the metal foil member having rigidity capable of holding its own shape inserted into the welding surface. Is not limited to this example. The rigidity of the metal foil member inserted into the welding surface may not be sufficient to maintain its own shape. Moreover, the structure by which the outer edge part of the metal foil member 235 is not return | folded with the outer edge part of the exterior may be sufficient.

For example, as shown in FIG. 9, a metal foil having both surfaces covered with a low melting point resin layer 23a having metal adhesion and a melting point lower than that of a thermoplastic resin film on the welding surface E ₀ w of the outer edge of the exterior In the battery in which the metal foil member 235 having the layer 23m is inserted, the exterior 20 is a laminate resin in which a convex portion 211 along the rectangular periphery for housing the power generating element body is embossed at least on one side The outer end edges of the film are formed by welding, and the outer end edge portion E ₀ long of the exterior can be folded back so as to follow the rising side surface 211 a of the convex portion 211.

Even in this configuration, a simple work, the end surface E ₀ e longitudinal outer edges E ₀ long could form the outer end surface covering portion 23Ae, the end surface of the outer edge portion E ₀ long laminated resin film E ₀ Corrosion starting from e can be prevented.

That is, similarly to the other embodiments, the molten resin of the low-melting point resin layer 23a can be protruded outside from the end surface E ₀ e of the outer end edge E ₀ long during welding.

[Second Modification]
Moreover, in each embodiment mentioned above, although the metal foil member showed the structure provided with the low melting-point resin layer on both surfaces of a metal foil layer, it is not restricted to this example. For example, as shown in FIG. 10, the metal foil member 236 is folded in half along the outer edge E ₀ long of the laminated resin film, and the fold mountain 236b is the end surface E _{0 of the} outer edge E ₀ long. It can be set as the structure arrange | positioned on the opposite side to e.

According to this configuration, out of the resin of the low melting point resin layer 23a of the metal foil member 236, the resin is folded in half to be sandwiched between the metal foil layers 23m, and the end surface E _{0 of the} outer edge E ₀ long from the folding mountain 236b. The outer end face covering portion 236ae that covers the end face E ₀ e more reliably can be formed by causing a resin having a flow path only in the e-side direction to flow during welding. Therefore, it is possible to better prevent corrosion starting from the end face E ₀ e of the outer edge E ₀ of the laminate resin film.

[Third Modification]
Moreover, in each embodiment mentioned above, although the low melting-point resin layer 23a of the metal foil member showed the structure which has uniform thickness along the surface of the metal foil layer 23m, it is not restricted to this example. For example, as shown in FIG. 11, the metal foil member 237 can be configured such that the low melting point resin layer 237a is formed thick on the outer end edge E ₀ long side of the exterior.

According to this configuration, the amount of resin flow in the low-melting point resin layer 237a of the metal foil member 237 is increased by the thickness formed in the vicinity of the end face E ₀ e of the outer edge E ₀ long of the laminated resin film. Since more can be secured, the outer end surface covering portion 236ae that covers the end surface E ₀ e can be more reliably formed. Therefore, it is possible to better prevent corrosion starting from the end face E ₀ e of the outer edge E ₀ of the laminate resin film.

In the other embodiments, the configuration is shown in which the outer outer edge E ₀ long on the long side of the laminate resin film is folded to form the exterior 20, but the outer edge E ₀ is not necessarily folded. It doesn't matter. For example, the whole having a thickness corresponding to the height of the electrode body 11 may be a substantially flat outer package.

  Moreover, although the exterior showed the structure by which the convex part which accommodates an electric power generation element body was emboss-molded in at least one side of the laminate resin film, the structure using the laminate resin film which is not emboss-molded may be sufficient. For example, a method of enclosing the electrode body with one laminated resin film and sealing it by welding three sides or four sides can be exemplified.

  Further, the two-folded metal foil member 236 of each modification described above or the metal foil member 237 having a thick low-melting point resin layer near the end face may be used for each battery of the first to third embodiments.

[Laminated sealed battery]
Hereinafter, the laminated sealed battery of the present invention will be described in addition to the above-described embodiments in an expanded or supplemental manner. The laminated sealed battery of the present invention can have the same configuration as a conventionally known laminated sealed battery except that it is a battery having the above-described exterior, and the type of the battery is not particularly limited. Further, in the laminated sealed battery of the present invention, the power generating element body is not particularly limited as long as it has a configuration including a positive electrode and a negative electrode.

  First, it is desirable to employ it in a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery in which moisture permeation into the power generation element body is a serious problem. A non-aqueous electrolyte secondary battery includes a positive electrode plate in which a positive electrode active material is held in a positive electrode current collector, a negative electrode plate in which a negative electrode active material is held in a negative electrode current collector, and an electrolyte dissolved in a non-aqueous solvent. If necessary, a power generating element body having a non-aqueous electrolyte in a state where a separator is disposed between a positive electrode plate and a negative electrode plate can be housed in an exterior. In addition, even in the case of other batteries in which intrusion of moisture does not become a problem, since it is often desirable that the sealing performance inside and outside the battery is high, the laminated sealed battery according to the present invention can be obtained.

  In the following description, a description will be given as appropriate mainly on a representative lithium ion secondary battery.

(Exterior)
The laminated sealed battery of the present invention houses a power generating element body with an exterior made of a laminated resin film obtained by laminating a metal foil with a thermoplastic resin. In the exterior according to the present invention, the outer edges of the laminated resin film are welded along the outer edges to seal the periphery of the power generating element body, and the power generating element body is stored in a sealed state.

  The exterior includes a storage portion for storing the power generation element body and an outer end edge portion in which the outer end edges of the laminated resin film are overlapped and the outer end edges are welded together. Even if the exterior is configured by combining two or more laminated resin films, housing the power generation element body, and welding the outer edges together to seal it, the power generation element body can be bent, wound, etc. by one laminate resin film It is also possible to have a configuration in which the outer edges are welded together and sealed in a state of enveloping. In addition, the storage portion can be satisfactorily formed by embossing a convex portion along the shape of the peripheral edge of the power generating element body on the laminated resin film by pressing or the like.

  The outer end edge portion is formed as a result of sealing the planned welding surface of the outer end edge of the laminated resin film after the power generation element body is stored inside the storage main body portion. The outer edge portion is a portion that seals the opening of the exterior and maintains the battery in a sealed state. The shape of the welded surface portion to be sealed by welding is not limited, but it is desirable that the area of the welded surface is large from the viewpoint of ensuring the welding or adhesive strength and improving the reliability. On the other hand, in order to increase the energy density per unit volume of the battery, the size of the laminated sealed battery should be reduced. However, it is desirable to minimize the area of the outer edge that does not directly contribute to the battery reaction. The method of sealing the exterior by welding the linear outer edge of the laminated resin film so as to have a rectangular welding surface along the periphery of the rectangular power generation element body is the reliability and energy density of the battery. It is desirable from the viewpoint of maintaining an equilibrium with

  As the laminate resin film constituting the laminate resin film case, a film used in a conventional laminate resin film case can be used.

  The laminate resin film has a configuration in which a thermoplastic resin layer is adhered to one side or both sides of a metal foil (copper, aluminum, stainless steel, etc.). In this case, the material can be changed between the portion in contact with the internal electrolyte and the portion to be joined by thermal fusion, and an appropriate material can be selected. In the laminate resin film, for example, the resin of the film layer forming the outer peripheral surface is typically made of a heat-resistant resin such as polyester such as polyethylene terephthalate or polyamide such as nylon, the metal foil is made of aluminum foil, and the inner peripheral surface is A film in which the resin of the weld layer to be formed is made of polyolefin such as polypropylene or polyethylene can be used. Each of the metal foil and the resin layer may be formed by stacking multiple layers.

  In addition, the metal foil and resin layer of the laminate resin film forming the exterior can be selected as necessary, such as moisture permeability, strength, mass, and chemical stability. Moreover, the thickness of the whole laminated resin film and each resin layer and metal foil is not specifically limited.

  The metal foil member is a resin layer that is a thermoplastic resin on one or both sides of a metal foil (copper, aluminum, stainless steel, etc.), has a metal adhesive property, and has a lower melting point than the resin of the laminate resin film, particularly the weld layer. It has the structure formed by sticking. “Low melting point” means, for example, a resin having a molding temperature of 200 ° C. or lower. As the low melting point resin layer having metal adhesion, an acid-modified polyolefin, a low melting point acrylic resin, or the like can be suitably used.

  Examples of acid-modified polyolefins include those in which functional groups having bonding properties with metals such as carboxyl groups, hydroxyl groups, maleic anhydride groups, acrylic acid groups, and acrylate groups are introduced into polyolefins such as polyethylene and polypropylene. Known olefin copolymers such as olefin copolymers obtained by polymerizing olefins such as ethylene and propylene and comonomers such as acrylic acid, vinyl acetate, glycidyl methacrylate, and methyl acrylate can be used.

  In addition, for example, acid-modified polypropylene obtained by graft copolymerization of unsaturated carboxylic acid or its anhydride to all or part of polypropylene constituting the main skeleton can be used.

  The polypropylene constituting the main skeleton of the modified polypropylene is a homopolymer of propylene, or a block copolymer or a random copolymer made of propylene and another monomer.

  Examples of other monomers include ethylene, 1-butene, isobutene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 2-methyl-1-pentene, 1-heptene and the like can be mentioned, and these may include one or a combination of two or more in polypropylene.

  Examples of the unsaturated carboxylic acid grafted onto polypropylene or its anhydride include unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, unsaturated dicarboxylic acids such as maleic acid and fumaric acid, and maleic anhydride. Examples thereof include unsaturated dicarboxylic acid anhydrides.

  The acid-modified polypropylene may contain one or a combination of two or more of these graft monomers. Among these, maleic anhydride-modified polypropylene is preferable.

  Moreover, as a low melting point acrylic resin, polymethyl acrylate, polymethyl methacrylate, polyethyl methacrylate, etc. can be used, and polymethyl methacrylate is preferable.

  In addition, the metal foil member can be suitably used by adhering a metal adhesive low melting point resin layer of about 20 to 50 μm per side to both surfaces of a metal foil of about 10 μm.

(Power generation element)
The power generation element body has positive and negative electrode bodies. Specifically, the structure which has the electrode body and nonaqueous electrolyte formed in the state which laminated | stacked the positive electrode plate and the negative electrode plate through the separator can be illustrated. At this time, the laminate may be wound to form a wound body. Furthermore, it is good also as a flat type wound body which compressed the wound body to radial direction.

  The negative electrode plate is prepared by suspending and mixing a negative electrode mixture composed of a negative electrode active material, a conductive agent and a binder in a suitable solvent, applying a slurry to one or both sides of the negative electrode current collector, and drying. Can be produced.

  The active material for the negative electrode is not particularly limited, and a conventionally known negative electrode active material can be used. Specifically, a substance exhibiting a capacity such as graphite can be specifically mentioned.

  The negative electrode active material may contain additives such as conventionally known conductive materials and binders.

  As the conductive material, a carbon material, metal powder, conductive polymer, or the like can be used. From the viewpoint of conductivity and stability, it is preferable to use a carbon material such as acetylene black, ketjen black, or carbon black.

  As binders, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), fluororesin copolymer (tetrafluoroethylene / hexafluoropropylene copolymer), SBR, acrylic rubber, fluorine rubber , Polyvinyl alcohol (PVA), styrene / maleic acid resin, polyacrylate, carboxymethyl cellulose (CMC), and the like.

  Examples of the solvent include organic solvents such as N-methyl-2-pyrrolidone (hereinafter referred to as NMP) or water.

  As the negative electrode current collector, a conventionally known current collector can be used, and a foil, mesh, or the like made of copper, stainless steel, titanium, or nickel can be used.

  The positive electrode plate is prepared by suspending and mixing a positive electrode mixture composed of a positive electrode active material, a conductive agent and a binder in a suitable solvent, applying a slurry to the positive electrode current collector, and drying. be able to.

As the positive electrode active material, various metal oxides, metal sulfides, lithium-containing oxides, conductive polymers, and the like can be used. For example, MnO ₂ , TiS ₂ , TiS ₃ , MoS ₃ , FeS ₂ , Li _(1-x) MnO ₂ , Li _(1-x) Mn ₂ O ₄ , Li _(1-x) CoO ₂ , Li _{(1- x) NiO 2, LiV 2 O} 3, V 2 O 5, polyaniline, polyparaphenylene, polyphenylene sulfide, polyphenylene oxide, polythiophene, polypyrrole, and derivatives thereof, can be specifically mentioned stable radical compound. In addition, x in these positive electrode active materials shows the number of 0-1. A material obtained by adding or substituting a transition metal such as Li, Mg, Al, or Co, Ti, Nb, or Cr may be used. Moreover, not only these lithium-metal composite oxides are used alone, but also a plurality of them can be mixed and used.

  Examples of the conductive material of the positive electrode include, but are not limited to, graphite fine particles, acetylene black, ketjen black, carbon black such as carbon nanofiber, and porous conductive carbon material.

  Examples of the binder include, but are not limited to, PVDF, ethylene-propylene-diene copolymer (EPDM), SBR, acrylonitrile-butadiene rubber (NBR), and fluorine rubber.

  As the solvent in which the positive electrode active material is dispersed, an organic solvent that dissolves the binder is usually used. Examples thereof include, but are not limited to, NMP, dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, NN-dimethylaminopropylamine, ethylene oxide, and tetrahydrofuran.

  As the positive electrode current collector, for example, a foil or mesh made of aluminum, stainless steel, copper, nickel, or the like can be used.

  As the non-aqueous solvent for dissolving the electrolyte in the electrolytic solution, a solvent containing at least one selected from ethylene carbonate, vinylene carbonate, dimethyl carbonate, ethylmethyl carbonate, and diethyl carbonate as a main component can be used.

The type of the electrolyte is not particularly limited, but an inorganic salt selected from LiPF ₆ , LiBF ₄ , LiClO ₄ and LiAsF ₆ , derivatives of these inorganic salts, LiSO ₃ CF ₃ , LiC (SO ₂ CF ₃ ) ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) _2, LiN (SO ₂ CF ₃ ) (SO ₂ C ₄ F ₉ ), and the like, and organic salts thereof It is desirable that it is at least one of the derivatives

  The concentration of the electrolyte is not particularly limited, and it is preferable to appropriately select the electrolyte and the organic solvent in consideration of the use.

  The separator plays a role of electrically insulating the positive electrode plate and the negative electrode plate and holding the electrolytic solution. As the separator, for example, a porous synthetic resin film, in particular, a porous film of polyolefin polymer (polyethylene, polypropylene) can be used. The separator is preferably larger than the positive electrode and the negative electrode in order to ensure insulation between the positive electrode and the negative electrode.

  The electrode body has a power extraction member made of a conductor electrically connected to each of the positive electrode plate and the negative electrode plate. The member for taking out electric power electrically connects the inside and the outside of the laminated resin film exterior. The member for extracting power can be a member (for example, an electrode terminal) electrically connected to each of the positive electrode plate and the negative electrode plate, or a tab provided on each of the positive electrode plate and the negative electrode plate.

  The member for taking out electric power can be fixed in the state inserted in the welding surface of the laminate resin film. A resin layer made of a resin different from the resin on the welding surface may be disposed between the power extraction member and the resin on the welding surface.

  A plurality of laminated sealed batteries according to the present invention may be combined to form an assembled battery. In this case, a casing made of a material having rigidity such as metal or resin in a state where the battery of the present invention in which the power generation element body is housed in the exterior of the laminated resin film is electrically connected in series and / or in parallel. It can be set as the structure accommodated in.

B, B2, B3: Batteries (laminated sealed batteries)
11: Electrode body
12: Positive terminal
13: Negative terminal
20: Exterior
21, 22: Laminated resin film
211: Convex part
211a: rising side
211b: inner surface (of convex curve)
211c: Convex part
213: The entire inner surface (of the laminated resin film) 231, 232, 233, 234, 235, 236, 237: Metal foil member
23a: Low melting point resin layer (adhesive low melting point resin layer)
23ae, 236ae, 237ae: outer end surface covering portion
23b ₁ : bent portion
23b ₂ : second bent portion
23m: Metal foil layer
23c ₁ , 234c ₁ : negative electrode lead terminal (metal foil terminal)
E ₀ : outer edge
E ₀ long: Longitudinal outer edge
E ₀ a, E ₀ c: Short outer edge (electrode outer edge)
E ₀ w: Welding surface
E ₀ e: End face
E ₁ : folded shape holding edge (outer edge)

Claims (14)

A power generating element body having a positive electrode (11a, 12) and a negative electrode (11c, 13);
It consists of a laminate resin film (21, 22) obtained by laminating a metal foil (21b, 22b) with a thermoplastic resin (21a, 22a, 21c, 22c), and the linear outer edges of the laminate resin film are the outer edges. In a laminated sealed battery comprising: an exterior (20) that is welded in a rectangular shape along an edge to seal a periphery of the power generation element body and store the power generation element body,
An adhesive low melting point resin layer (23a) having metal adhesion and having a melting point lower than that of the thermoplastic resin film is formed on the welding surface (E ₀ w) of the outer edge (E ₀ long, E ₁ ) of the exterior. ) At least one surface of the metal foil member (231m to 237) provided with a metal foil layer (23m) covered ,
And an outer end surface covering portion (23ae, 236ae, 237ae) that covers the end surface (E ₀ e) of the outer edge of the exterior, which is formed from the resin of the adhesive low melting point resin layer. Laminated sealed battery.   The laminate according to claim 1, wherein the metal foil member (237) is formed such that the thickness of the adhesive low melting point resin layer (237a) is increased on the outer edge side of the exterior. Sealed battery. The metal foil member (236) is folded in half along the outer edge of the laminated resin film, and the fold mountain (236b) is disposed on the opposite side of the end surface (E ₀ e) of the outer edge of the exterior. The laminated sealed battery according to claim 1 or 2, wherein the battery is sealed. The exterior is formed by welding the outer end edges of the laminated resin film (21) in which a convex portion (211) along the peripheral edge of the rectangular shape for housing the power generating element body is embossed at least on one side. Molded,
The laminated sealed battery according to any one of claims 1 to 3, wherein an outer edge of the exterior is folded back so as to follow the rising surface (211a) of the convex portion. The metal foil layer of the metal foil member (231, 232, 234) has a rigidity capable of maintaining its own shape,
5. The laminated sealed battery according to claim 4, wherein the outer edge (E ₁ ) of the exterior is folded back together with the outer edge of the metal foil member inserted into the welding surface.   The convex curved part (211c) forming the convex part is another metal foil provided with a metal foil layer having at least one surface covered with the adhesive low melting point resin layer and having rigidity capable of maintaining its shape. The laminated sealed battery according to claim 5, wherein the inner surface (211b) is covered with a member (233).   The metal foil member (232) is connected to the portion of the metal foil member inserted into the welding surface so as to continuously cover the inner surface of the convex curved portion that forms the convex portion. The laminated sealed battery according to claim 5, wherein the battery is sealed.   The laminate according to claim 5, wherein the metal foil member (234) is overlapped with the laminate resin film so as to cover the entire inner surface (213) of the embossed laminate resin film. Sealed battery. The positive electrode and the negative electrode are respectively led out from a pair of opposing electrode lead-out outer edges (E ₀ a, E ₀ c) among the outer edges of the exterior, and the metal foil layer is made of a conductive metal,
One end (23c ₂ ) of the metal foil member (231, 232) is connected to the positive electrode or the negative electrode at the welding surface of the electrode lead-out outer edge (E ₀ c) of either the positive electrode or the negative electrode,
The metal foil member has a positive or negative metal foil terminal portion (23c ₁ ) extending from the other electrode lead-out outer edge (E ₀ a) by extending the other end of the metal foil member to the outside. The laminated sealed battery according to any one of claims 1 to 7, further comprising: The positive electrode and the negative electrode are respectively led out from a pair of electrode lead-out outer edges of the outer edge of the exterior, and the metal foil layer is made of a conductive metal,
Of the outer edge of the metal foil member (234), one side (234c) is connected to the positive electrode or the negative electrode at the welding surface of the electrode outer edge of either the positive electrode or the negative electrode,
The other end of the metal foil member is electrically insulated from the negative electrode or the positive electrode and extended to the outside at the other outer end edge of the electrode. The laminated sealed battery according to claim 8, further comprising a metal foil-like terminal portion (234c ₁ ) of a positive electrode or a negative electrode.   The laminate sealed battery according to any one of claims 1 to 10, wherein the thickness of the metal foil layer is 10 µm to 500 µm.   The laminated sealed battery according to any one of claims 1 to 11, wherein the metal foil layer contains, as a main component, any one of aluminum, stainless steel, and copper.   13. The laminated sealed battery according to claim 1, wherein the adhesive low melting point resin layer is made of an acid-modified polyolefin resin or a low melting point acrylic resin as a raw material.   The laminated sealed battery according to any one of claims 1 to 13, wherein the surface of the metal foil layer is chromate-treated.

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