JPWO2017047473A1 - battery - Google Patents

Abstract

  An electrode laminate in which the positive electrode main body portion 22 and the negative electrode main body portion 32 are stacked via a separator, a positive electrode lead tab 120 connected via the positive electrode main body portion 22 and the positive electrode terminal portion 24, a negative electrode main body portion 32, and a negative electrode A rectangular laminated film exterior material that forms a housing space for housing the electrode laminate and the electrolyte solution by forming a sealing region around the negative electrode pull-out tab 130 connected via the terminal portion 34 and thermal welding. 80, a pressure release part 90 that releases pressure as the internal pressure rises in the accommodation space on one of the four sides of the rectangular laminate film exterior material 80, and a part of the separator Both a separator / film exterior material welded portion 93 welded with a rectangular film laminate exterior material are provided.

Description

  The present invention relates to a battery such as a lithium ion secondary battery having a structure in which an electrode laminate in which a plurality of positive electrode main body portions and a plurality of negative electrode main body portions are laminated via a separator is accommodated in a film exterior material.

  Lithium-ion secondary batteries have been widely used as power storage devices used as power sources for portable small devices such as mobile phones and digital cameras. However, in recent years, power sources for mobile means such as electric bikes and electric bicycles, as well as residential and commercial facilities Demand is expanding even for large-sized, large-capacity, and large-current power supplies.

  In particular, a lithium ion secondary battery using a flexible laminate film as an exterior material has attracted attention because it is lightweight, highly safe, and suitable for high-density mounting. A battery module in which a plurality of lithium ion secondary batteries using such a flexible laminate film as an exterior material is used as an assembled battery is housed in a module case made of resin, metal, or a combination thereof, for example. Used.

  When the battery module as described above is applied to a moving body such as a bicycle or an automobile, the battery constituting the battery module continues to receive relatively large vibrations. Here, in a battery having a configuration in which an electrode laminate composed of a plurality of electrodes and a separator sandwiched between electrodes is sealed with a film sheathing material, when the electrode laminate moves within the film sheathing material due to impact or the like, It is desirable to suppress the movement of the electrode laminate inside the package made of the film exterior material because there is a possibility that a problem occurs as a battery.

Then, the technique which restrict | limits the movement of the electrode laminated body in a film exterior material is proposed, for example, in patent document 1 (Unexamined-Japanese-Patent No. 2013-73913), several electrodes and several separators are alternated. A laminated electrode laminate, and an exterior body film that constitutes a package that encloses the electrode laminate by overlapping and joining peripheral portions thereof, and the plurality of separators are planar. Including a large separator and a small planar separator, the large planar separator projecting to the side of the electrode laminate as viewed in a plane, and on the inner side of the joint between the peripheral portions of the outer package film A battery bonded to the outer package film has been proposed.
JP 2013-73913 A

  By the way, when a voltage outside the standard range is applied to the battery during use of the battery, gas species may be generated due to electrolysis of the electrolyte solvent, and the internal pressure of the battery may increase. Furthermore, even if the battery is used at a high temperature outside the standard range, a substance that is a source of gas species is generated due to decomposition of the electrolyte salt or the like.

  Basically, it is ideal to use the battery within the standard range so as not to generate gas, but the battery control circuit may fail for some reason and an abnormal voltage is applied, or for some reason. If the surroundings become abnormally hot, a large amount of gas may be generated in some cases.

  The generation of gas inside the battery causes an increase in the internal pressure of the battery. In order to prevent the internal pressure from rising excessively and the battery from exploding, the battery with a film as the exterior material expands if the internal pressure rises too much, and eventually the exterior material ruptures and gas is emitted from that location. Although it erupts, it is not possible to specify where the rupture occurs, so depending on the ruptured location, it may adversely affect surrounding equipment.

  However, the conventional battery described in Patent Document 1 has a problem because no measures are taken against the rupture of the film exterior material accompanying the increase in internal pressure as described above.

  In addition, in a battery sealed with a film exterior material, in order to cope with a problem related to an increase in internal pressure, the strength of a specific portion of a welded portion that seals the electrode laminate is weakened, and this is used as a safety valve. A configuration has been proposed, and it is conceivable to apply such a configuration to the battery described in Patent Document 1. However, when this configuration is adopted, a new problem that the area of the battery becomes large occurs.

  The present invention solves the above problems, and a battery according to the present invention includes an electrode laminate in which a positive electrode main body and a negative electrode main body are stacked via a separator, and the positive electrode main body. A positive electrode extraction tab connected via a positive electrode terminal portion, a negative electrode extraction tab connected via the negative electrode main body portion and a negative electrode terminal portion, and a sealing region is formed around the electrode by thermal welding, whereby the electrode A rectangular film sheathing material that forms a housing space for housing the laminate and the electrolyte solution, wherein one of the four sides of the rectangular film sheathing material has an increased internal pressure in the housing space. Accordingly, both a pressure release portion for releasing pressure and a separator / film exterior material welded portion in which a part of the separator and a rectangular film exterior material are welded are provided.

  The battery according to the present invention includes, on one side of the four sides of the rectangular film exterior material, a pressure release portion that releases pressure as the internal pressure of the accommodation space increases, and a part of the separator and the rectangular film exterior Both the separator / film exterior material welded portion welded to the material are provided, and according to such a battery according to the present invention, the movement of the electrode laminate can be restricted while suppressing the area of the battery. It is possible to improve the impact resistance and to take measures against rupture of the film exterior material accompanying the increase in internal pressure.

1 is a perspective view of a battery 100 according to an embodiment of the present invention. It is the figure which looked at the battery 100 which concerns on embodiment of this invention from the direction of the arrow X of FIG. 1 (stacking direction of the electrode laminated body 60). It is a figure which shows the positive electrode 20 of the battery 100 which concerns on embodiment of this invention. It is a figure which shows the negative electrode 30 of the battery 100 which concerns on embodiment of this invention. It is a figure which shows the separator 40 of the battery 100 which concerns on embodiment of this invention. It is a figure which shows the separator 40 of the battery 100 which concerns on embodiment of this invention. FIG. 6 is a diagram illustrating a stacking order of components in an electrode stack 60. It is sectional drawing of FIG. 2A-A '. It is a perspective view explaining the peeling stress which acts when the boundary of the heat welding part of the laminate film exterior material 80 is a shape without an unevenness | corrugation. It is a perspective view explaining the peeling stress which acts on the protrusion welding part 85. FIG. It is a top view which shows progress of peeling in the protrusion welding part 85. FIG. It is a figure which shows the separator 40 used with the battery 100 which concerns on other embodiment of this invention. It is a figure explaining the lamination | stacking order of each structure in the electrode laminated body 60 of the battery 100 which concerns on other embodiment of this invention. It is a figure which shows the separator 40 used with the battery 100 which concerns on other embodiment of this invention. It is a perspective view of the battery 100 which concerns on the performance of the separator extension piece 44, and used for numerical examination of the number of sheets which concerns on embodiment of this invention. FIG. 16 is a diagram illustrating a separator 40 of the battery 100 illustrated in FIG. 15.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a battery 100 according to an embodiment of the present invention. In FIG. 1, the configuration accommodated in the laminate film exterior member 80 is indicated by a dotted line.

  FIG. 2 is a view of the battery 100 according to the embodiment of the present invention as viewed from the direction of the arrow X in FIG. 1 (stacking direction of the electrode stack 60). The plan view of the battery 100 is defined as shown in FIG. 2, and when the battery 100 is viewed in FIG. 2, the battery main body 110 except for the areas of the positive electrode extraction tab 120 and the negative electrode extraction tab 130 is shown. The area is defined as the area of the battery 100.

  When the battery 100 is viewed in FIG. 2, the battery main body 110 includes a first side 111, a second side 112 that faces the first side 111, a third side 113, and a fourth side that faces the third side 113. Side 114. The positive electrode extraction tab 120 and the negative electrode extraction tab 130 are arranged to be extracted from the first side 111.

  On the other hand, the ultrasonic welding portion 93 that fixes the electrode laminate 60 to the laminate film exterior member 80 and the pressure release portion 90 that releases the gas when the internal pressure of the battery body portion 110 rises are on the second side 112 side. It has come to be arranged.

  In the present embodiment, as the battery 100, a lithium ion secondary battery that is one type of electrochemical element in which charge and discharge are performed by moving lithium ions between a negative electrode and a positive electrode will be described as an example. Can also be applied to other types of batteries.

  A battery 100 according to an embodiment of the present invention includes an electrode laminate 60 in which a plurality of positive electrodes 20 and a plurality of negative electrodes 30 are laminated via a separator 40, and an electrolyte (not shown) having a rectangular laminate in plan view. The structure is accommodated in the film exterior member 80.

  In addition to the laminate of the plurality of positive electrodes 20 and the plurality of negative electrodes 30 via the separator 40 as described above, a sheet-like positive electrode and a sheet-like negative electrode were laminated on the electrode laminate 60 via the separator. The thing which makes a laminated body by winding this thing and compressing this is also contained.

  Further, in the present embodiment, the electrode stack 60 is described in which a plurality of positive electrodes 20 and a plurality of negative electrodes 30 are stacked via a separator 40. However, as a minimum unit of the electrode stack 60, Theoretically, one positive electrode 20 and one negative electrode 30 may be laminated via a separator 40.

  Here, the positive electrode 20, the negative electrode 30, and the separator 40 used for the battery 100 according to the embodiment of the present invention will be described. FIG. 3 is a diagram showing the positive electrode 20 of the battery 100 according to the embodiment of the present invention, and FIG. 4 is a diagram showing the negative electrode 30 of the battery 100 according to the embodiment of the present invention.

  The positive electrode 20 includes a rectangular positive electrode main body portion 22 and a strip-shaped positive electrode terminal portion 24 extending from the positive electrode main body portion 22. In the positive electrode main body 22, a positive electrode active material 26 such as a lithium cobalt composite oxide is applied to a thin plate-like aluminum plate.

  The negative electrode 30 includes a rectangular negative electrode main body portion 32 and a strip-shaped negative electrode terminal portion 34 extending from the negative electrode main body portion 32. In the negative electrode main body 32, a negative electrode active material 36 such as graphite is applied to a thin nickel plate or copper plate.

  5 and 6 are views showing the separator 40 of the battery 100 according to the embodiment of the present invention. In addition, the separator 40 shown in FIG. 5 and the separator 40 shown in FIG. 6 have a front-back relationship, and the separator 40 of one type of shape is prepared substantially.

  The separator 40 includes a rectangular separator body 42 and a strip-shaped separator extension piece 44 that extends from the separator body 42. The separator 40 is a sheet-like member that can be impregnated with an electrolytic solution, such as a microporous film (microporous film), a nonwoven fabric, or a woven fabric made of a thermoplastic resin such as polyolefin.

  Next, a method for forming the electrode laminate 60 by laminating the positive electrode 20, the negative electrode 30, and the separator 40 as described above will be described. FIG. 7 is a diagram illustrating the stacking order of the components in the electrode stack 60.

  As shown in FIG. 7, the positive electrode 20, the negative electrode 30, and the separator 40 are laminated according to the rule of the separator 40, the negative electrode 30, the separator 40, the positive electrode 20, the separator 40,. The positive electrode 20 is laminated so that all the positive electrode terminal portions 24 overlap one side when viewed from the lamination direction. Further, the negative electrode 30 is laminated such that all the negative electrode terminal portions 34 overlap the other side when viewed from the lamination direction.

  Further, as shown in FIG. 7, the separator 40 has the separator extending pieces 44 alternately arranged in one side, the other side, one side, the other side, and so on when viewed from the stacking direction. Laminated to be arranged. The separator extension piece 44 is ultrasonically welded to the laminate film exterior member 80 at two locations as viewed from the stacking direction.

  If the electrode laminate 60 accommodated in the laminate film exterior material 80 is moved due to impact or the like, there is a possibility that a defect may occur as the battery 100. Therefore, the electrode laminate 60 within the package made of the laminate film exterior material 80. It is desirable to suppress the movement of

  Therefore, in the battery 100 according to the present invention, as described above, the separator extension pieces 44 of the separator 40 are the two ultrasonic welding portions 93 on the second side 112 side of the laminate film exterior material 80, and the laminate film. It is configured to be fixed to the exterior material 80. FIG. 8 is a cross-sectional view of FIG. 2A-A '. As shown in FIG. 8, movement of the electrode laminate 60 is restricted by fixing the electrode laminate 60 to the laminate film exterior material 80 via the separator extension piece 44.

  On the other hand, on the first side 111 side of the battery main body 110 of the battery 100 according to the present invention, the positive electrode extraction tab 120 and the negative electrode extraction tab 130 are fixed to the laminate film exterior material 80 by welding. .

  As described above, in the battery 100 according to the present invention, the positive electrode extraction tab 120 and the negative electrode extraction tab 130 are fixed to the laminate film exterior material 80 on the first side 111 side of the battery main body 110, thereby stacking the electrodes. While restricting the movement of the body 60 and also on the second side 112 side facing the first side 111, the separator extension piece 44 is fixed to the laminate film exterior member 80 at two locations, so that the electrode laminate 60. Regulate the movement of

  As a result, the electrode laminate 60 accommodated in the laminate film exterior member 80 is fixed to the laminate film exterior member 80 at two opposing sides and the movement is restricted. It has a structure with excellent impact properties.

  In the present embodiment, the separator extension piece 44 is fixed to the laminate film exterior material 80 at two locations on one side of the battery main body 110. Thus, the separator extension piece 44 is It is preferable that the laminated film exterior material 80 is dispersed and fixed to a plurality of locations. This is to suppress energy for welding by suppressing the number of separator extension pieces 44 stacked in one welding portion.

  In the present invention, the location where the separator extension piece 44 is fixed to the laminate film exterior member 80 may be one location on one side. In short, as long as the side where the positive electrode extraction tab 120 and the negative electrode extraction tab 130 are fixed to the laminate film exterior member 80 and the side where the separator extension piece 44 is fixed to the laminate film exterior member 80 face each other. Good.

  However, as in the present embodiment, the part where the separator extension piece 44 is disposed is dispersed in a plurality of places as described above, and a part of the separator 40 (separator extension piece 44) and the laminate film exterior material 80 are dispersed. It is a desirable embodiment to disperse the separator / film exterior material welded portion (ultrasonic welded portion 93) that welds a plurality of locations.

  The positive terminal portions 24 of the plurality of positive electrodes 20 are conductively connected to the positive electrode extraction tab 120. Further, the negative terminal portions 34 of the plurality of negative electrodes 30 are conductively connected to the negative electrode extraction tab 130. An aluminum plate is used for the positive electrode extraction tab 120, and a nickel plate or a copper plate is used for the negative electrode extraction tab 130. When the negative electrode lead tab 130 is formed of a copper plate, the surface may be plated with nickel.

  In addition, when using what laminated | stacked the one positive electrode 20 and the one negative electrode 30 via the separator 40 as the minimum unit of the electrode laminated body 60, it connects so that one positive electrode terminal part 24 may be conductively connected to the positive electrode extraction tab 120. Then, one negative terminal portion 34 may be conductively connected to the negative electrode lead tab 130.

  The laminate film exterior material 80 is composed of two laminate films surrounding and sandwiching the electrode laminate 60 from both sides in the lamination direction, and heat-welding the opposing surfaces that overlap each other around the electrode laminate 60, The body 60 is sealed together with the electrolytic solution.

  In FIG. 1 and FIG. 2, the hatched portion indicates a thermal welding portion 81 (sealing region) that seals the electrode laminate 60 and the electrolytic solution by thermally welding the laminate film exterior material 80.

  The laminate film constituting the laminate film exterior material 80 is generally used for this type of film exterior battery as long as it has flexibility and can seal the battery element 2 so that the electrolyte does not leak. Can be used.

  As a typical layer structure of a laminate film used for the laminate film exterior material 80, a structure in which a metal thin film layer and a heat-weldable resin layer are laminated, or a surface of the metal thin film layer opposite to the heat-welded resin layer is provided. Furthermore, the structure which laminated | stacked the protective layer which consists of films, such as polyester, nylon, such as a polyethylene terephthalate, is mentioned. When sealing the electrode laminate 60 and the electrolytic solution, the electrode laminate 60 is surrounded by facing the heat-welding resin layer.

   As the metal thin film layer, for example, a foil made of Al, Ti, Ti alloy, Fe, stainless steel, Mg alloy or the like having a thickness of 10 μm to 100 μm can be used. The resin used for the heat-welding resin layer is not particularly limited as long as it can be heat-welded. For example, polypropylene, polyethylene, acid-modified products thereof, polyphenylene sulfide, polyester such as polyethylene terephthalate, polyamide, An ethylene-vinyl acetate copolymer can be used. The thickness of the heat-welding resin layer is preferably 10 μm to 200 μm, more preferably 30 μm to 100 μm.

  Next, the characteristic structure of the pressure release portion 90 in the heat welding portion (sealing region) 81 of the laminate film exterior material 80 will be described. The pressure release part 90 is also characterized by being provided on the second side 112 side of the battery main body part 110.

  As shown in FIG. 2, on the second side 112 of the battery main body portion 110, two non-welded portions 87, which are portions where the laminate film exterior materials 80 are not thermally welded, are accommodated in the accommodating portion 82 (battery element accommodating portion). ) And is provided in a cove shape with respect to the accommodating portion 82.

  The two non-welded portions 87 are spaced apart from each other in the direction along the peripheral edge of the heat-welded portion (sealing region) 81, and the region between the two non-welded portions 87 is two non-welded portions. A protruding welded portion 85 that protrudes from the heat welded portion (sealing region) 81 outside the portion 87 toward the accommodating portion 82 is formed. A through-hole 88 that penetrates the laminate film exterior material 80 is formed in the protruding welded portion 85.

  In the battery 100 configured as described above, when a voltage outside the standard range is applied during use or when gas is generated from the electrode laminate 60 or the like due to a temporary high temperature, the laminate film exterior material The internal pressure of 80 increases.

  When the internal pressure rises, the laminate film exterior material 80 tends to swell in a dome shape, and a peeling stress acts on a portion where the laminate film exterior materials 80 are thermally welded to each other. At this time, the peeling stress acts intensively on the protruding welded portion 85 between the two non-welded portions 87, and the peeling of the heat-welded portion of the exterior film 5 proceeds preferentially at the protruding welded portion 85. . As the internal pressure increases, the separation reaches the position of the through hole 88, so that the battery element housing portion communicates with the outside of the laminate film exterior member 80, and the increased pressure is released through the through hole 88. Therefore, the gas can be ejected from a specific position before the laminate film exterior material 80 of the battery 100 is ruptured, and the burst of the laminate film exterior material 80 of the battery 100 and the ejection of gas in an unintended direction can be prevented. Can do.

  Hereinafter, the progress of peeling of the laminate film exterior material 80 accompanying the increase in internal pressure will be described in detail.

  When the boundary between the heat-welded region and the non-heat-welded region of the laminate film exterior material 80 has an uneven shape, the peeling stress F1 acts only in one direction as shown in FIG. Then, the peeling proceeds toward the outer edge of the laminate film exterior material 80.

  However, when the protruding welded portion 85 is provided as in the present embodiment, the non-fused portion 87 is also filled with gas as shown in FIG. Therefore, in addition to the peeling stress F1 acting on the tip of the protruding welded portion 85, the peeling stress F2 also acts on the side edge.

  Therefore, a peeling stress larger than the other part acts as a resultant force on the corner portion of the protruding welded portion 85, and the laminate film exterior material 80 is peeled preferentially over the other portion at the corner portion. . When the laminate film exterior material 80 is peeled off at the corner, the corner is rounded, but the protruding weld 85 still maintains a convex shape, and the protruding weld 85 is peeled from a plurality of directions. Works. Accordingly, the laminate film exterior material 80 is peeled off while the protrusion film weld material 85 is peeled off at the projecting weld portion 85 until the projecting weld portion 85 is substantially eliminated while reducing the sharpness of the convex shape. Progresses preferentially over site.

  The progress of peeling of the laminate film exterior material 80 at the protruding welded portion 85 is shown in FIG. As shown in FIG. 11, in the protruding weld portion 85, peeling proceeds from both sides of the protruding weld portion 85 as a → b → c as the internal pressure increases. The peeling position of the laminate film exterior material 80 depends on the material of the laminate film exterior material 80, the width W of the protruding weld portion 85, the protruding length L of the protruding weld portion 85, and the internal pressure.

  Therefore, if the material of the laminate film exterior material 80, the width W of the protruding welded portion 85, and the protruding length L of the protruding welded portion 85 are determined in advance, the position of the through hole 88 can be adjusted to adjust the battery element storage portion. The release pressure, which is the internal pressure of the battery element storage portion when the inside and the outside of the battery communicate with each other, can be arbitrarily set. That is, if the through hole 88 is provided at a position close to the tip of the protruding weld portion 85, the pressure can be released with a low internal pressure, and if the through hole 88 is provided near the base of the protruding weld portion 85, the pressure can be increased to a high internal pressure. Does not open.

  In the laminate film exterior member 80 of the battery 100, the preferable design opening pressure is 0.05 MPa to 1 MPa, more preferably 0.1 MPa to 0.4 MPa as an increase from the atmospheric pressure. If the opening pressure is too low, even a slight trouble such as when a large current flows temporarily or when the temperature becomes temporarily high will cause the battery 100 to become inoperable. On the other hand, when the release pressure is too high, the welded portion of the laminate film sheathing material 80 and the welded sealing portion of the drawer tab are opened at other portions before the peeling of the laminate film sheathing material 80 to the through hole 88 proceeds. There is an increased risk that the gas will be ejected in the direction not to go.

  In the battery 100 according to the present invention as described above, the pressure is released to one side (second side 112) of the four sides of the rectangular laminate film exterior member 80 as the internal pressure of the accommodation space of the electrode laminate 60 increases. And a separator / film exterior material welded portion (ultrasonic welded portion 93) in which a part of the separator 40 (separator extension piece 44) and the laminate film exterior material 80 are welded are provided. Thus, according to the battery 100 according to the present invention, the movement of the electrode stack 60 can be restricted while suppressing the area of the battery 100, and the impact resistance can be improved. It becomes possible to take measures against rupture of the laminate film exterior material 80 accompanying the increase in internal pressure.

  Further, in the battery 100 according to the present invention, the separator / film which is a point for welding the separator extension piece 44 of the separator 40 and the laminate film exterior material 80 on the second side 112 of the rectangular laminate film exterior material 80. The exterior material welded portion has a structure arranged at two positions on both sides of the pressure release portion 90, and the movement of the electrode laminate 60 can be effectively restricted.

  Next, another embodiment of the present invention will be described. This embodiment is different from the previous embodiment in the configuration of the electrode laminate 60, thereby suppressing energy when welding the separator extension piece 44 and the laminate film exterior member 80.

  Hereinafter, this embodiment will be described focusing on differences from the previous embodiment. In the previous embodiment, in order to reduce the number of separator extension pieces 44 stacked in one welded portion, the number of places where the separator extension pieces 44 are arranged is two when viewed from the stacking direction. The separators 40 are alternately extended in the stacking order of the separators 40.

  In this embodiment, as shown in FIG. 12, the separator 40 having only the rectangular separator main body 42, which does not have the strip-shaped separator extension piece 44, is also used, so that the laminate film is formed at one welding portion. The number of separator extension pieces 44 fixed to the exterior member 80 is further reduced.

  FIG. 13 is a diagram illustrating the stacking order of the components in the electrode stack 60 of the battery 100 according to another embodiment of the present invention.

  In the present embodiment, as shown in FIG. 13, the separator 40 having the separator extension piece 44 from above, the negative electrode 30, the separator 40 not having the separator extension piece 44, the positive electrode 20, and the separator having the separator extension piece 44. 40, negative electrode 30, separator 40 not having separator extension piece 44, positive electrode 20, separator 40 having separator extension piece 44,..., Positive electrode 20, negative electrode 30, and separator 40 are laminated. . That is, when the electrode laminate 60 is configured, by laminating the components, the separator 40 that does not have the separator extension piece 44 is also appropriately laminated, so that the separator extension piece 44 of the separator 40 and the laminate film exterior material are laminated. The number of separator extension pieces 44 in the separator / film exterior material welding portion, which is a point for welding 80, is reduced.

  In order to weld the separator extension piece 44 and the laminate film exterior member 80, the ultrasonic welding portion 93 can be configured using ultrasonic welding also in this embodiment. At this time, the number of separator extension pieces 44 at the point where ultrasonic welding is performed is smaller than that in the previous embodiment, so that energy during welding can be suppressed.

  It should be noted that in what pattern the separator 40 that does not have the separator extension piece 44 is interposed in the separator 40 that has the separator extension piece 44 to form the electrode laminate 60. 60, the coefficient of friction between the electrode laminate 60 and the laminate film exterior member 80, and the like.

  Next, another embodiment of the present invention will be described. In the embodiments so far, the separator / film exterior material welded portion, which is the point at which the separator extension piece 44 of the separator 40 and the laminate film exterior material 80 are welded, is used as the second side 112 of the rectangular laminate film exterior material 80. The number of separator extension pieces 44 to be fixed at the separator / film exterior material welded portion is reduced by using the two locations.

  On the other hand, in this embodiment, the separator / film exterior material welded portion is fixed at the separator / film exterior material welded portion at four locations on the second side 112 of the rectangular laminate film exterior material 80. The number of separator extending pieces 44 is further reduced.

  FIG. 14 is a diagram showing a separator 40 used in a battery 100 according to another embodiment of the present invention. FIG. 14A shows the first pattern separator 40, and the dotted separator extension piece 44 shows the separator extension piece 44 of the separator 40 in a front-back relationship with the solid line separator 40.

  14B shows the separator 40 of the second pattern, and the line separator extension piece 44 shows the separator extension piece 44 of the separator 40 that is in the front and back relation with the solid line separator 40. FIG. Yes.

  By using the separator 40 having a pattern as shown in FIG. 14, four points on the second side 112 of the laminate film exterior material 80 can be provided as the separator / film exterior material welded portions. It becomes possible to further reduce the number of separator extending pieces 44 fixed at the material welding portion.

  Furthermore, in this embodiment, it is also possible to use together the separator 40 which does not have the separator extension piece 44 shown in FIG.

  In the embodiments so far, ultrasonic welding is used when forming the separator / film exterior material welded portion by welding the separator extension piece 44 and the laminate film exterior material 80. In the embodiment, since the number of separator extension pieces 44 fixed at one separator / film exterior material welded portion can be further reduced, it is also possible to use thermal welding that performs welding with lower energy than ultrasonic welding. It becomes.

  Next, the performance and the number of sheets required as the separator extension piece 44 to be welded and fixed to the laminate film exterior material 80 in the separator / film exterior material welding portion will be numerically studied.

  FIG. 15 is a perspective view of the battery 100 according to the embodiment of the present invention used for numerical examination of the performance and the number of the separator extension pieces 44. In FIG. 15, the pressure release unit 90 is not shown.

  So far, in the embodiment described above, an example in which a plurality of separator / film exterior material welded portions are provided on one side of the battery main body 110 has been described. The separator / film exterior material welded portion (ultrasonic welded portion 93) is provided as an example, but the concept in the following explanation is that a plurality of separator / film exteriors are provided on one side of the battery main body 110. The present invention can also be applied to the battery 100 provided with the material welding portion.

  FIG. 16 is a diagram showing the separator 40 of the battery 100 shown in FIG. In the separator 40 of the battery 100 according to the present embodiment, the separator extending pieces 44 that can be overlapped with each other are provided so as to extend from the separator main body 42 even when the front and back sides are related.

In the battery 100 using the separator 40 as described above, the tensile strength of the separator extension piece 44 is F, the cross-sectional area of the separator extension piece 44 is S, and the separator extension fixed at the separator / film exterior material welded portion. When the number of pieces 44 is N and the mass of the battery is W,
150W <F × S × N
It is preferable to have the following relationship. This is because, if this relationship can be satisfied, the impact resistance of the battery loaded on the aircraft can be satisfied.

In the battery 100 shown in FIGS. 15 and 16, the mass of the battery 100 is 800 g. The thickness of the separator extension piece 44 in the stacking direction is 0.025 mm. Also,
Tensile strength of separator extension piece 44: 400 [kgf / cm ² ]
Cross-sectional area of the separator extension piece 44; 86 [mm] × 0.025 [mm] = 0.0215 [cm ² ]
The total number of separator extension pieces 44 of the battery 100 is 34 sheets.

Here, when all the separator extension pieces 44 are welded and fixed to the laminate film exterior material 80 at the separator / film exterior material welded portion, N = 34,
F × S × N = 400 × 0.0215 × 34 = 292.4 [kgf]
It is.

On the other hand, when every other separator extension piece 44 is welded and fixed to the laminate film exterior material 80 at the separator / film exterior material welded portion, N = 17,
F × S × N = 400 × 0.0215 × 17 = 146.2 [kgf]
It is.

When every two layers of separator extension pieces 44 are welded and fixed to the laminate film exterior material 80 at the separator / film exterior material welded portion, N = 11,
F × S × N = 400 × 0.0215 × 11 = 94.6 [kgf]
It is.

Since the mass of the battery 100 is 800 g,
150W = 120 [kgf]
It is.

Therefore, satisfying the relationship 150W <F × S × N is
When all the separator extension pieces 44 are welded and fixed to the laminate film exterior material 80 at the separator / film exterior material welded part, and every other separator extended piece 44 is laminated at the separator / film exterior material welded part. These are two patterns when the film exterior material 80 is welded and fixed.

  On the other hand, when every two layers of separator extension pieces 44 are welded and fixed to the laminate film exterior material 80 at the separator / film exterior material welded portion, stacking deviation due to vibration and impact cannot be prevented.

  As described above, in the battery 100 according to the present embodiment, desired impact resistance can be imparted to the battery 100 by designing the battery 100 to have a relationship of 150 W <F × S × N. It becomes possible.

  As described above, the battery according to the present invention includes a pressure release portion that releases pressure in accordance with an increase in internal pressure of the housing space, and a rectangular shape with a part of the separator, on one side of the four sides of the rectangular film exterior material. Both the separator / film exterior material welded portion welded to the film exterior material are provided, and according to the battery according to the present invention, the movement of the electrode laminate is restricted while suppressing the area of the battery. Thus, it is possible to improve the impact resistance and to take measures against rupture of the film exterior material accompanying an increase in internal pressure.

Industrial availability

  The present invention relates to a battery using a flexible laminate film that is lightweight, high in safety, and high in energy density as an exterior material. In a battery having a structure in which an electrode laminate is sealed with a film sheathing material, if the electrode laminate moves within the film sheathing material due to an impact or the like, a defect may occur as a battery. It is desirable to suppress the movement of the electrode stack inside. On the other hand, when gas is generated inside the battery, it is desirable to provide a configuration for preventing a situation in which the internal pressure of the battery is increased by the gas, the film exterior material is ruptured, and the gas is ejected.

  Therefore, the battery according to the present invention has a rectangular shape in one side of the four sides of the rectangular film exterior material, a pressure release portion that releases pressure as the internal pressure of the accommodation space increases, and a part of the separator. Both the separator / film exterior material welded portion welded to the film exterior material are provided, and according to the battery according to the present invention, the movement of the electrode laminate is restricted while suppressing the area of the battery. It is possible to improve the impact resistance, and it is possible to take measures against the rupture of the film outer packaging material accompanying the increase in internal pressure, and the industrial utility is very large.

DESCRIPTION OF SYMBOLS 20 ... Positive electrode 22 ... Positive electrode main-body part 24 ... Positive electrode terminal part 26 ... Positive electrode active material 30 ... Negative electrode 32 ... Negative electrode main-body part 34 ... Negative electrode terminal part 36 ... Negative electrode Active material 40 ... Separator 42 ... Separator main body 44 ... Separator extension piece 60 ... Electrode laminate 80 ... Laminate film outer packaging material 81 ... Thermal welding part (sealing region)
82 ... Accommodating part 85 ... Projection welding part 87 ... Non-welding part 88 ... Through-hole 90 ... Pressure release part 93 ... Ultrasonic welding part 100 ... Battery 110 ... Battery main body 111 ... 1st side 112 ... 2nd side 113 ... 3rd side 114 ... 4th side 120 ... Positive electrode extraction tab 130 ... Negative electrode extraction tab

Claims (10)

An electrode laminate in which a positive electrode main body and a negative electrode main body are laminated via a separator;
A positive electrode pull-out tab connected via the positive electrode main body portion and the positive electrode terminal portion;
A negative electrode pull-out tab connected via the negative electrode body part and the negative electrode terminal part;
A battery having a rectangular film exterior material that forms a housing space for housing the electrode laminate and the electrolytic solution by forming a sealing region around by heat welding,
A pressure release portion that releases pressure as the internal pressure of the housing space increases on one of the four sides of the rectangular film exterior material, and a separator / with a part of the separator and the rectangular film exterior material welded Both the film exterior material welding parts are provided, The battery characterized by the above-mentioned. 2. The battery according to claim 1, wherein the positive electrode pull-out tab and the negative electrode pull-out tab are pulled out from the rectangular film exterior material on a side opposite to the one side. 3. The battery according to claim 1, wherein a part of the separator that is welded at the separator / film exterior material welded portion is an extended piece that extends from the main body. The battery according to any one of claims 1 to 3, wherein a plurality of the separator / film exterior material welded portions are provided. The battery according to any one of claims 1 to 4, wherein the separator / film exterior material welded portion is formed by ultrasonic welding. The battery according to any one of claims 1 to 4, wherein the separator / film exterior material welded portion is formed by thermal welding. The tensile strength of the extended piece of the separator is F, the cross-sectional area of the extended piece of the separator is S, the number of the extended pieces of the separator to be welded at the separator / film exterior material welded portion is N, the mass of the battery Is W
150W <F × S × N
The battery according to claim 3, wherein the battery has the following relationship. The battery according to any one of claims 1 to 7, wherein the pressure release portion releases the pressure by causing the accommodation space and the external space to communicate with each other by peeling the film exterior material. . The battery according to any one of claims 1 to 8, wherein the pressure release portion has a structure in which two non-welded portions are spaced apart from each other in a direction along a peripheral edge of the sealing region. 10. The battery according to claim 9, wherein the pressure release portion includes a protruding weld portion that protrudes from a sealing region outside the two non-welded portions toward the accommodation space.

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