Power storage device

Abstract

To provide a technique of suppressing acceleration of sudden temperature rise in a case.SOLUTION: A power storage device 1 includes an electrode body 20, an electrode body holder 70, and a case 10. The electrode body 20 includes a positive electrode 22 and a negative electrode 24. The electrode body holder 70 stores the electrode body 20, and is made of resin. The case 10 stores the electrode body 20 and the electrode body holder 70. The electrode body holder 70 has a coating layer 90, on an outer surface 71 on the inner wall surface side of the case 10. The coating layer 90 contains microcapsules which contain an addition agent having a fire extinction function and are made of resin.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a power storage device.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2015-222653 discloses a non-aqueous electrolyte secondary battery including an electrode body, an electrolytic solution, microcapsules, and a battery case. In the non-aqueous electrolyte secondary battery, the microcapsules are formed of a material that can be dissolved at least partially at a temperature of 90°C or higher and lower than 110°C, and contain a flame-retardant ionic liquid. The microcapsules are arranged at a position where they are immersed in the electrolytic solution when the electrolytic solution reaches a temperature at which at least a part of the microcapsules can be dissolved, outside the electrode body within the battery case. The publication describes that such a configuration can more reliably suppress abnormal heat generation of the battery.

[0003] Japanese Patent Application Laid-Open No. 2007-273127 discloses a non-aqueous secondary battery including a positive electrode plate, a negative electrode plate, a separator, and an electrolytic solution. In the non-aqueous secondary battery, thermally expandable microcapsules are included at the interface between the separator or the positive electrode plate or the negative electrode plate and the separator. The publication describes that with such a configuration, even when a rapid heat generation reaction occurs within the battery case, the microcapsules can thermally expand with a fast responsiveness to heat, and it is possible to prevent the insulating property of the separator from disappearing.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] As research and development of energy storage devices progresses, interest in the safety of energy storage devices is increasing more and more. The inventor believes that when a rapid temperature rise occurs inside the case, it is desired to suppress the acceleration of this temperature rise.

Means for Solving the Problem

[0006] According to the technology disclosed herein, an energy storage device including an electrode body, an electrode body holder, and a case is disclosed. The electrode body includes a positive electrode and a negative electrode. The electrode body holder houses the electrode body and is made of resin. The case houses the electrode body and the electrode body holder. The electrode body holder has a coating layer on the outer surface on the inner wall surface side of the case. The coating layer includes resin microcapsules containing an additive having a fire extinguishing function. According to such a configuration, when a rapid temperature rise occurs inside the case, it is possible to suppress the acceleration of this temperature rise.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0008] Hereinafter, an embodiment of the technology disclosed herein will be described. The embodiments described herein are not intended to particularly limit the technology disclosed herein. The technology disclosed herein is not limited to the embodiments described herein unless otherwise specified. The drawings are schematically drawn and do not necessarily reflect the actual objects. Members and parts having the same function may be appropriately assigned the same reference numerals, and redundant descriptions may be omitted. In the drawings, the signs "F", "Rr", "R", "L", "U", and "D" indicate front, rear, right, left, upper, and lower, respectively. The notation "A~B" indicating a numerical range means "A or more and B or less" and also includes the meaning of "exceeding A and being less than B" unless otherwise specified.

[0009] As used herein, the "power storage device" refers to a device in which charge carriers move between a pair of electrodes (a positive electrode and a negative electrode) through an electrolyte to cause charge and discharge. Such power storage devices include secondary batteries such as lithium-ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries; and capacitors such as lithium-ion capacitors and electric double layer capacitors. Hereinafter, as an example of the above-described power storage device, embodiments in the case of a lithium-ion secondary battery will be described.

[0010] FIG. 1 is a schematic cross-sectional view of the power storage device 1. FIG. 1 shows the cross-sectional structure of the power storage device 1 along the wide surface 12a. As shown in FIG. 1, the power storage device 1 includes a case 10, an electrode body 20, a positive electrode terminal 30, a negative electrode terminal 40, a positive electrode current collector 50, a negative electrode current collector 60, an electrode body holder 70, an insulating member 80, and an electrolyte (not shown).

[0011] The case 10 is, for example, a member that houses the electrode body 20, the electrode body holder 70, and the electrolyte. Although not particularly limited, for example, the case 10 may be made of aluminum or an aluminum alloy from the viewpoints of weight reduction and ensuring required rigidity.

[0012] As shown in FIG. 1, the case 10 has a case body 12 and a sealing plate 14. The case body 12 is, for example, the main body of the case 10 that houses the electrode body 20 therein. In this embodiment, the case body 12 has an opening 12h, a pair of opposing wide surfaces 12a, a pair of opposing narrow surfaces 12b, and a bottom surface 12c. The bottom surface 12c faces the opening 12h here. The bottom surface 12c is rectangular here and has a pair of opposing long sides and a pair of opposing short sides. The pair of opposing wide surfaces 12a are surfaces extending from the pair of opposing long sides on the bottom surface 12c. The pair of opposing narrow surfaces 12b are surfaces extending from the pair of opposing short sides on the bottom surface 12c. Note that in this specification, the description of "rectangular shape" or "rectangle" includes a shape in which the straight long side and short side are joined to each other via a curve, a shape in which at least one of the long side and short side is not straight but is curved, uneven, or bent and is composed of a plurality of straight lines or curves, etc.

[0013] The opening 12h is, for example, a portion where the sealing plate 14 is attached. Here, the opening 12h is formed by being surrounded by the upper edges of the pair of wide surfaces 12a and the upper edges of the pair of narrow surfaces 12b, and is rectangular. The sealing plate 14 is fitted into the opening 12h and joined (e.g., welded), whereby the case body 12 and the sealing plate 14 are integrated and the case 10 is hermetically sealed.

[0014] The sealing plate 14 is, for example, a flat member that seals the opening 12h. Therefore, the shape of the sealing plate 14 may be a shape corresponding to the shape of the opening 12h. In this embodiment, the sealing plate 14 is rectangular. Here, when the sealing plate 14 is attached to the opening 12h, the sealing plate 14 faces, for example, the bottom surface 12c. As shown in FIG. 1, the sealing plate 14 has mounting holes (not shown) and a discharge valve, and a liquid injection hole 17. The mounting hole is, for example, a through hole for attaching an electrode terminal. Therefore, the sealing plate 14 preferably has a mounting hole for attaching the positive electrode terminal 30 and a mounting hole for attaching the negative electrode terminal 40, respectively. A part of the electrode terminal is inserted into such a mounting hole. The discharge valve is, for example, a thin-walled portion. Here, the discharge valve is configured to break when the pressure in the case 10 becomes a predetermined value or more and discharge the gas in the case 10 to the outside. The liquid injection hole 17 is a site for injecting the electrolytic solution. As shown in FIG. 1, a sealing member 16 is attached to the liquid injection hole 17. Although not particularly limited, the sealing member 16 is preferably made of metal. The sealing member 16 is, for example, welded to the sealing plate 14.

[0015] FIG. 2 is a schematic diagram of the electrode body 20. The electrode body 20 is, for example, a power generation element of the power storage device 1 including a positive electrode and a negative electrode. The electrode body 20 has, for example, a laminated structure in which a sheet-shaped positive electrode 22 and a sheet-shaped negative electrode 24 are laminated with a separator 23 interposed therebetween. The electrode body 20 is housed in the case 10 in a state where the sheet-shaped positive electrode 22 and the sheet-shaped negative electrode 24 are overlapped toward a pair of wide surfaces 12a.

[0016] As shown in FIG. 2, the electrode body 20 is, for example, a wound electrode body in which a sheet-shaped positive electrode 22 and a sheet-shaped negative electrode 24 are laminated with a separator 23 interposed therebetween and wound in the sheet longitudinal direction LD. The electrode body 20 can be produced, for example, by winding the positive electrode 22, the negative electrode 24, and the separator 23 into a cylindrical body and press-forming such a cylindrical body. Therefore, the electrode body 20 has a flat shape. The electrode body 20 has, for example, a pair of opposed flat surfaces 20a (see FIG. 1).

[0017] One end face 20b of the electrode body 20 faces one narrow-width face 12b (the left narrow-width face 12b in FIG. 1), and the other end face 20c faces the other narrow-width face 12b (the right narrow-width face 12b in FIG. 1). Here, the end face 20b is the laminated surface of the uncoated portion 22c1 of the positive current collector foil 22c and is an open surface. Here, the end face 20c is the laminated surface of the uncoated portion 24c1 of the negative current collector foil 24c and is an open surface. As shown in FIGS. 1 and 2, the electrode body 20 is housed in the case body 12 such that the winding axis direction WD is substantially parallel to the left-right direction of the power storage device 1. Further, the winding axis WL of the electrode body 20 is substantially perpendicular to the wide-width face 12a and the narrow-width face 12b and is substantially parallel to the sealing plate 14.

[0018] As shown in FIG. 2, the positive electrode 22 has a long strip-shaped positive current collector foil 22c (for example, an aluminum foil) and a positive electrode active material layer 22a fixed on at least one surface of the positive current collector foil 22c. Although not particularly limited, a protective layer (not shown) may be provided at one side edge portion of the positive electrode 22 in the winding axis direction WD as needed. Note that, as the constituent material of the positive electrode active material layer 22a and the constituent material of the protective layer, those used in this type of power storage device (in this embodiment, a lithium-ion secondary battery) may be used without particular limitation.

[0019] A strip-shaped uncoated portion 22c1 is provided along the longitudinal direction LD at one end portion (the left end portion in FIG. 2) of the positive current collector foil 22c in the winding axis direction WD. The uncoated portion 22c1 is a part of the positive current collector foil 22c. The uncoated portion 22c1 is a portion of the positive current collector foil 22c where the positive electrode active material layer 22a is not coated. In this embodiment, the uncoated portion 22c1 protrudes in the winding axis direction WD from the separator 23. The uncoated portion 22c1 is laminated at one end portion (the left end portion in FIG. 2) in the winding axis direction WD. As shown in FIG. 1, the positive current collector 50 is joined to the uncoated portion 22c1.

[0020] As shown in FIG. 2, the negative electrode 24 has a long strip-shaped negative electrode current collector foil 24c (for example, a copper foil) and a negative electrode active material layer 24a fixed on at least one surface of the negative electrode current collector foil 24c. Note that, as the constituent material of the negative electrode active material layer 24a, those used in this type of power storage device (in this embodiment, a lithium-ion secondary battery) may be used without particular limitation.

[0021] At one end (the right end in FIG. 2) in the winding axis direction WD of the negative electrode current collector foil 24c, a strip-shaped uncoated portion 24c1 is provided along the longitudinal direction LD. The uncoated portion 24c1 is a part of the negative electrode current collector foil 24c. The uncoated portion 24c1 is a portion of the negative electrode current collector foil 24c where the negative electrode active material layer 24a is not formed. In this embodiment, the uncoated portion 24c1 protrudes in the winding axis direction WD from the separator 23. For example, the uncoated portion 24c1 is laminated at one end (the right end in FIG. 2) in the winding axis direction WD. As shown in FIG. 1, the negative electrode current collector 60 is joined to the uncoated portion 22c1.

[0022] The separator 23 is a member that insulates the positive electrode active material layer 22a of the positive electrode 22 and the negative electrode active material layer 24a of the negative electrode 24. In this embodiment, the separator 23 constitutes the outer surface of the electrode body 20. As the separator 23, for example, a porous sheet made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP) is used.

[0023] The positive electrode terminal 30 is, for example, a member electrically connected to the positive electrode 22 of the electrode body 20. As described above, the positive electrode terminal 30 is inserted through the mounting hole provided in the sealing plate 14 and is disposed outside and inside the case body 12. For this reason, the positive electrode terminal 30 may have, for example, a portion disposed outside the case 10, a portion inserted through the mounting hole, and a portion disposed inside the case 10. The positive electrode terminal 30 is made of, for example, aluminum or an aluminum alloy.

[0024] The positive electrode current collector 50 is, for example, a member that electrically connects the positive electrode 22 and the positive electrode terminal 30 inside the case 10. In the form shown in FIG. 1, the positive electrode current collector 50 is plate-shaped and extends from the sealing plate 14 toward the electrode body 20. Here, the positive electrode current collector 50 is connected to the positive electrode terminal 30 at one end (the upper end in FIG. 1) and is connected to the electrode body 20 at the other end (the lower end in FIG. 1). In this embodiment, the connection between the positive electrode current collector 50 and the positive electrode terminal 30 is realized by joining (e.g., welding) one end of the positive electrode current collector 50 and the positive electrode terminal 30. In this embodiment, the connection between the positive electrode current collector 50 and the electrode body 20 is realized by joining (e.g., welding) the other end of the positive electrode current collector 50 and the non-coated portion 22c1. The positive electrode current collector 50 is made of, for example, aluminum or an aluminum alloy.

[0025] The negative electrode terminal 40 is, for example, a member that is electrically connected to the negative electrode 24 of the electrode body 20. The negative electrode terminal 40 is made of, for example, copper or a copper alloy. The negative electrode terminal 40 may have, for example, the same configuration as the positive electrode terminal 30. For this reason, the description of the configuration of the negative electrode terminal 40 is omitted here. The negative electrode current collector 60 is, for example, a member that electrically connects the negative electrode 24 and the negative electrode terminal 40 inside the case 10. The negative electrode current collector 60 is made of, for example, copper or a copper alloy. The negative electrode current collector 60 may have, for example, the same configuration as the positive electrode current collector 50. For this reason, the description of the configuration of the negative electrode current collector 60 is omitted here.

[0026] FIG. 3 is a schematic perspective view of the electrode body holder 70. The electrode body holder 70 is, for example, a resin member that covers the electrode body 20. The electrode body holder 70 is, for example, bag-shaped and partially open. As shown in FIGS. 1 and 3, the electrode body holder 70 is closed at the lower end and open at the upper end. In this embodiment, the electrode body holder 70 is housed in the case 10 with the electrode body 20 housed therein. In the form shown in FIG. 3, the electrode body holder 70 has a bottom portion 70A, a pair of opposing first side wall portions 70B, and a pair of opposing second side wall portions 70C. As shown in FIGS. 1 and 3, the bottom portion 70A is rectangular and is a portion facing the bottom surface 12c of the case body 12. The pair of first side wall portions 70B are portions extending from a pair of opposing long sides of the bottom portion 70A and face the wide surface 12a of the case body 12. The pair of second side wall portions 70C are portions extending from a pair of opposing short sides of the bottom portion 70A and face the narrow surface 12b of the case body 12.

[0027] Incidentally, when an abnormality such as an internal short circuit occurs in the power storage device, the temperature inside the case may rise rapidly. Due to such a rapid temperature rise, for example, the temperature of the material inside the case may reach the melting point or boiling point, and the internal pressure may increase. From the viewpoint of safely using the power storage device, when a rapid temperature rise occurs inside the case, it is necessary to suppress the acceleration of this temperature rise. Considering such circumstances, the inventor thought that it would be desirable to suppress the acceleration of the rapid temperature rise inside the case.

[0028] FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3. FIG. 4 shows the cross-sectional structure of the electrode body holder 70 in the first side wall portion 70B1. As shown in FIGS. 3 and 4, the electrode body holder 70 is provided with a coating layer 90 on the outer surface 71. In this embodiment, the outer surface 71 of the electrode body holder 70 is a surface facing the inner surface of the case body 12 (the surface on the side of the electrode body 20 in the case body 12), and is a surface opposite to the inner surface 72 of the electrode body holder 70. The inner surface 72 of the electrode body holder 70 referred to here is a surface facing the electrode body 20 in the electrode body holder 70. In the form shown in FIGS. 3 and 4, the electrode body holder 70 is bag-shaped and includes a resin base material 75 and a coating layer 90. The electrode body holder 70 is provided with the coating layer 90 on one side (outer surface 71) of the base material 75.

[0029] The electrode body holder 70 may be provided with a coating layer 90 at least on the outer surface 71 of the first region 701 and the outer surface 71 of the second region 702. The first region 701 is, for example, a region facing the joint between the positive electrode 22 and the positive electrode current collector 50. In this embodiment, the first region 701 is provided at the positive electrode side end (the left end in FIGS. 1 and 3) of the first side wall portion 70B1 facing the joint between the positive electrode 22 and the positive electrode current collector 50. In this case, with respect to the length LA in the long side direction of the first side wall portion 70B1, the length L1 of the first region 701 in the same direction is preferably approximately 1 / 8 LA to 1 / 2 LA (1 / 4 LA to 1 / 3 LA). With respect to the length HA in the short side direction of the first side wall portion 70B1, the length H1 (not shown) of the first region 701 in the same direction is preferably at least approximately 1 / 4 HA, for example at least 1 / 3 HA, more preferably at least 1 / 2 HA, even more preferably at least 3 / 4 HA, and particularly preferably the same as HA (H1 = HA). The second region 702 is, for example, a region facing the joint between the negative electrode 24 and the negative electrode current collector 60. In this embodiment, the second region 702 is provided at the negative electrode side end (the right end in FIGS. 1 and 3) of the first side wall portion 70B1 facing the joint between the negative electrode 24 and the negative electrode current collector 60. In this case, with respect to the length LA in the long side direction of the first side wall portion 70B1, the length L2 of the second region 702 in the same direction is preferably approximately 1 / 8 LA to 1 / 2 LA (1 / 4 LA to 1 / 3 LA). With respect to the length HA in the short side direction of the first side wall portion 70B1, the length H2 (not shown) of the second region 702 in the same direction is preferably at least approximately 1 / 4 HA, for example at least 1 / 3 HA, more preferably at least 1 / 2 HA, even more preferably at least 3 / 4 HA, and particularly preferably the same as HA (H2 = HA). The area of the first region 701 and the area of the second region 702 may be the same or different.

[0030] As long as the effects of the technology disclosed herein are realized, although not particularly limited, when the area of the outer surface 71 of the electrode body holder 70 is taken as 100%, the area of the coating layer 90 is, for example, 40% or more, may be 50% or more, preferably 60% or more, more preferably 70% or more, still more preferably 80% or more, particularly preferably 90% or more, and the closer to 100% the better. In this embodiment, the electrode body holder 70 is provided with the coating layer 90 on the entire outer surface 71. In the forms shown in FIGS. 1 and 3, the coating layer 90 is provided on the outer surface of any of the bottom portion 70A, the pair of first side wall portions 70B, and the pair of second side wall portions 70C. Although not particularly limited, the thickness of the coating layer 90 is preferably approximately 0.1 mm to 0.5 mm, preferably 0.3 mm or less, and more preferably 0.25 mm or less.

[0031] The resin constituting the electrode body holder 70 is not particularly limited as long as it is a resin used for this kind of application. As the resin constituting the electrode body holder 70, for example, polyolefins such as polyethylene and polypropylene can be preferably used.

[0032] The coating layer 90 contains, for example, resin microcapsules containing an additive having a fire extinguishing function (hereinafter also referred to as a "fire extinguishing agent"). In this embodiment, "the microcapsule contains a fire extinguishing agent" means that the microcapsule and the fire extinguishing agent are integrated, and for example, refers to a form in which the fire extinguishing agent is encapsulated in a hollow microcapsule. The coating layer 90 may be composed of microcapsules containing a fire extinguishing agent, and may contain a binder, an inorganic filler, etc. as required. When the entire coating layer 90 is taken as 100% by volume, the proportion of the microcapsules is, for example, 60% by volume or more, preferably 70% by volume or more, more preferably 80% by volume or more, and still more preferably 90% by volume or more. Such a proportion may be, for example, 100% by volume or less, 98% by volume or less, or 95% by volume or less.

[0033] The resin constituting the microcapsules is preferably a resin having a melting point within a range of, for example, 70°C to 170°C, preferably within a range of 80°C to 160°C, more preferably within a range of 90°C to 150°C, and even more preferably within a range of 100°C to 140°C. The resin constituting the microcapsules is preferably a resin having a melting point equal to or higher than the melting point of the resin constituting the electrode body holder 70. Examples of the resin constituting the microcapsules include polyolefins such as polyethylene and polypropylene; acrylic resins; polyvinyl chloride; and the like.

[0034] Although not particularly limited, the average particle diameter of the microcapsules is preferably, for example, 0.1 μm to 100 μm. From the viewpoint of retaining more microcapsules on the outer surface 71 of the electrode body holder 70 and better realizing the effects of the technology disclosed herein, the average particle diameter is preferably 1 μm to 75 μm, and more preferably 5 μm to 50 μm. The average particle diameter of the microcapsules may be, for example, a measured value obtained using a laser diffraction particle size distribution measuring device, or a nominal value of a manufacturer or the like.

[0035] In this embodiment, the term "fire extinguishing agent" is used for components that are recognized by those skilled in the art as having a fire extinguishing function, and does not necessarily mean that the fire extinguishing function is actually exhibited within the case 10. The fire extinguishing agent is not particularly limited, and for example, various components having a cooling fire extinguishing ability, an endothermic ability, a suffocation fire extinguishing ability, or an inhibitor fire extinguishing ability can be used. The fire extinguishing agent may be solid, liquid, or gas at normal temperature. The fire extinguishing agent is, for example, alkali compounds such as sodium bicarbonate, sodium carbonate, potassium bicarbonate, potassium carbonate, ammonium bicarbonate, and ammonium carbonate; ammonium hydrogen phosphate; halogen compounds such as dodecafluoro-2-methylpentan-3-one (3M TM Novec TM 1230 fire extinguishing agent); and the like.

[0036] Binders such as water-dispersible binders and water-soluble binders can be preferably used. As the binder, for example, styrene-butadiene rubber; celluloses such as carboxymethyl cellulose and hydroxypropyl cellulose; polyvinyl alcohol; etc. can be preferably used. As the inorganic filler, inorganic fillers used for this kind of application such as alumina and silica can be used without particular limitation.

[0037] The method (manufacturing method) for producing the electrode body holder 70 is not particularly limited, but includes, for example, a first preparation step, a second preparation step, a mixing step, a coating step, and a drying step. The first preparation step is, for example, a step of preparing the base material 75 of the electrode body holder 70. The coating layer 90 is not provided on the base material 75 prepared in this step. In this embodiment, first, a resin sheet is prepared, and the resin sheet is bent at a predetermined portion to form a bag shape. By going through the first preparation step, the base material 75 is produced. Note that in this step, it is only necessary to prepare the bag-shaped base material 75. Therefore, the bag-shaped base material 75 is not limited to the one prepared by bending the resin sheet as described above. As the base material 75, a pre-formed bag-shaped one may be used.

[0038] The second preparation step is, for example, a step of preparing the materials for producing the coating layer 90. In this embodiment, the materials are microcapsules containing a fire extinguishing agent, a binder, and a solvent. The microcapsules containing a fire extinguishing agent may be purchased products from manufacturers or the like, or may be prepared using conventionally known procedures (for example, refer to the procedures described in paragraph 0026 of the specification of the above Patent Document 1 and the procedures described in Japanese Patent Application Laid-Open No. 10-270084). Note that the method for preparing the microcapsules containing a fire extinguishing agent does not particularly characterize the technology disclosed here. Therefore, the description of the preparation method itself is omitted here. As the binder, the above-described binder may be prepared. As the solvent, for example, water may be prepared. If necessary, an inorganic filler may be prepared.

[0039] The mixing step is, for example, a step of mixing the materials prepared in the second preparation step. In this embodiment, in the mixing step, the materials prepared in the second preparation step are put into a commercially available mixer and uniformly mixed to obtain a slurry for forming a coating layer. The mixing conditions are not particularly limited and may be set as appropriate.

[0040] The coating step is, for example, a step of coating the outer surface of the base material 75 prepared in the first preparation step with the slurry for forming a coating layer obtained in the mixing step. In this embodiment, in the coating step, the slurry for forming a coating layer is applied to the outer surface of the base material 75 in the region where the coating layer 90 is to be formed. The procedure for applying the slurry for forming a coating layer to the base material 75 is not particularly limited, and a conventionally known procedure may be adopted. The drying step is a step of drying the solvent from the slurry for forming a coating layer applied to the base material 75 in this step after the coating step. The drying conditions of the solvent are not particularly limited and may be set as appropriate. By passing through the drying step, the coating layer 90 is formed on the base material 75.

[0041] As shown in FIG. 1, an insulating member 80 is disposed between the positive electrode terminal 30 and the sealing plate 14, and between the negative electrode terminal 40 and the sealing plate 14. The insulating member 80 is disposed, for example, between the outer surfaces of the positive electrode terminal 30 and the sealing plate 14, between the inner surfaces of the positive electrode terminal 30 and the sealing plate 14, and along the inner peripheral surface of the mounting hole. The same applies to the negative electrode side, and the insulating member 80 is disposed, for example, between the negative electrode terminal 40 and between the outer side surface, the inner surface, and the mounting hole of the sealing plate 14. The insulating member 80 may be integrally molded or may be a combination of molded parts for each of a plurality of parts.

[0042] The electrolyte contains, for example, an electrolyte salt and a non-aqueous solvent. Examples of the electrolyte salt include LiPF6 and the like. The concentration of the electrolyte salt in the electrolyte is, for example, 0.7 mol / L to 1.3 mol / L. The non-aqueous solvent is preferably, for example, carbonates. Examples of the carbonates include ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), monofluoroethylene carbonate (MFEC), difluoroethylene carbonate (DFEC), monofluoromethyl difluoromethyl carbonate (F-DMC), trifluorodimethyl carbonate (TFDMC), and the like. These can be used alone or in combination of two or more.

[0043] The power storage device 1 is used for various applications. Among them, it can be preferably used as a power source (driving power source) for a motor mounted on vehicles such as passenger cars and trucks. The type of the vehicle is not particularly limited, and preferred examples include, for example, plug-in hybrid vehicles (PHEVs), hybrid vehicles (HEVs), battery electric vehicles (BEVs), and the like.

[0044] As described above, the power storage device 1 includes an electrode body 20, an electrode body holder 70, and a case 10. The electrode body 20 includes a positive electrode 22 and a negative electrode 24. The electrode body holder 70 houses the electrode body 20 and is made of resin. The case 10 houses the electrode body 20 and the electrode body holder 70. The electrode body holder 70 is provided with a coating layer 90 on the outer surface 71 on the inner wall surface side of the case 10. The coating layer 90 contains resin microcapsules containing a fire extinguishing agent.

[0045] The electrode body holder 70 is provided with a coating layer 90 containing resin microcapsules containing a fire extinguishing agent. As a result, when a rapid temperature rise occurs in the case 10, the microcapsules melt and the fire extinguishing agent is released. Thereby, it is possible to suppress the acceleration of the temperature rise in the power storage device 1. In addition, in the power storage device 1, since the coating layer 90 is provided on the electrode body holder 70, the formation of the coating layer 90 does not change the configuration of the electrode body 20 itself. For this reason, it is considered that there is no decrease in the capacity of the power storage device 1 due to the formation of the coating layer 90.

[0046] The power storage device 1 may further include a positive electrode current collector 50 and a negative electrode current collector 60. The electrode body holder 70 may be provided with the coating layer 90 at least on the outer surface of the first region 701 and the outer surface of the second region 702. The first region 701 may be a region facing the joint between the positive electrode 22 and the positive electrode current collector 50. The second region 702 may be a region facing the joint between the negative electrode 24 and the negative electrode current collector 60. The joint between the positive electrode 22 and the positive electrode current collector 50 and the joint between the negative electrode 24 and the negative electrode current collector 60 are sites where the temperature tends to rise relatively easily in the case 10. By providing the coating layer 90 on the outer surfaces of the regions facing these sites, the effects of the technology disclosed herein can be better realized.

[0047] The electrode body holder 70 may be provided with the coating layer 90 entirely on the outer surface. By providing the coating layer 90 on the entire outer surface of the electrode body holder 70, the effect of enhancing the acceleration of the temperature rise in the case 10 can be further enhanced.

[0048] The melting point of the resin constituting the microcapsules may be equal to or higher than the melting point of the resin constituting the electrode body holder 70. By using microcapsules having a melting point higher than that of the resin constituting the electrode body holder 70, for example, when a rapid temperature rise occurs in the case 10, the electrode body holder 70 melts first. As a result, the microcapsules adhere to the electrode body 20, so that the acceleration of the temperature rise in the electrode body 20 can be better suppressed.

[0049] The fire extinguishing agent may be dodecafluoro-2-methylpentan-3-one. Such a fire extinguishing agent is an example of a fire extinguishing agent in which the effects of the technology disclosed herein are appropriately realized.

[0050] The technology disclosed herein may include aspects described in each of the following items. - Item 1 - An electrode body including a positive electrode and a negative electrode, A resin electrode body holder that houses the electrode body, A case that houses the electrode body and the electrode body holder, comprising The electrode body holder is provided with a coating layer including resin microcapsules containing an additive having a fire extinguishing function on an outer surface on the inner wall surface side of the case, a power storage device. - Item 2 - A positive electrode current collector electrically connected to the positive electrode in the case, A negative electrode current collector electrically connected to the negative electrode in the case, further comprising The electrode body holder is provided with the coating layer at least on an outer surface of a region facing a joint portion between the positive electrode and the positive electrode current collector and on an outer surface of a region facing a joint portion between the negative electrode and the negative electrode current collector, the power storage device according to Item 1. - Item 3 - The electrode body holder is provided with the coating layer on the entire outer surface, the power storage device according to Item 1 or 2. - Item 4 - The melting point of the resin constituting the microcapsules is equal to or higher than the melting point of the resin constituting the electrode body holder, the power storage device according to any one of Items 1 to 3. - Item 5 - The additive is dodecafluoro-2-methylpentan-3-one, the power storage device according to any one of Items 1 to 4.

[0051] Although the embodiments of the technology disclosed herein have been described above, it is not intended to limit the technology disclosed herein to the above embodiments. The technology disclosed herein can also be implemented in other embodiments. The technology described in the claims includes various modifications and changes to the embodiments exemplified above. For example, it is possible to replace a part of the above-described embodiments with other modified forms, and it is also possible to add other modified forms to the above-described embodiments. Further, if the technical feature is not described as essential, it can be appropriately deleted.

Explanation of Signs

[0052] 1 Power storage device 10 Case 20 Electrode body 30 Positive electrode terminal 40 Negative electrode terminal 50 Positive electrode current collector 60 Negative electrode current collector 70 Electrode body holder 80 Insulating member 90 Coating layer

Claims

1. An electrode body including a positive electrode and a negative electrode, A resin electrode body holder for housing the electrode body, A case for housing the electrode body and the electrode body holder, Comprising: The electrode body holder includes a coating layer containing resin microcapsules containing an additive having a fire extinguishing function on the outer surface on the inner wall surface side of the case. A power storage device.

2. A positive electrode current collector electrically connected to the positive electrode in the case, A negative electrode current collector electrically connected to the negative electrode in the case, Further comprising: The electrode body holder includes the coating layer at least on the outer surface of a region facing the joint between the positive electrode and the positive electrode current collector and on the outer surface of a region facing the joint between the negative electrode and the negative electrode current collector. The power storage device according to claim 1.

3. The electrode body holder includes the coating layer on the entire outer surface. The power storage device according to claim 1.

4. The melting point of the resin constituting the microcapsules is equal to or higher than the melting point of the resin constituting the electrode body holder. The power storage device according to any one of claims 1 to 3.

5. The additive is dodecafluoro-2-methylpentan-3-one. The power storage device according to any one of claims 1 to 3.

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