Sealed battery

Abstract

Provided is a sealed battery capable of suppressing cracking of a side wall portion of an outer can. A sealed battery according to one embodiment of the present disclosure is provided with: a bottomed cylindrical outer can having an opening; a sealing body that closes the opening; and a winding-type electrode body housed in the outer can, in which an exhaust valve is provided to either the bottom of the outer can or the sealing body, one of both ends of the outermost peripheral end of the electrode body close to the exhaust valve is fixed by a first fixing member, and one of both ends of the outermost peripheral end away from the exhaust valve is fixed by a second fixing member. The value obtained by dividing the thermal conductivity in the thickness direction of the first fixing member by the volume of the first fixing member is smaller than the value obtained by dividing the thermal conductivity in the thickness direction of the second fixing member by the volume of the second fixing member.

Description

Technical Field

[0001] The present disclosure relates to sealed batteries. Background Art

[0002] In recent years, battery modules with multiple sealed batteries have been used in automotive batteries, etc. In addition to the safety of one sealed battery, the safety of the module has also become extremely important. Generally, a gas exhaust valve is provided at the bottom of the outer can of the sealed battery and at least one of the sealing body. When the internal pressure of the battery rises due to abnormal heating, etc., the gas generated inside the battery is discharged. For example, Patent Document 1 discloses a cylindrical battery, in which a gas exhaust valve is provided by forming an annular thin-walled portion at the bottom of the outer can, and the ratio of the area of ​​the gas exhaust valve to the area of ​​the bottom is set to 10% or more.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2014 / 045569 Summary of the invention

[0006] However, if the gas is not discharged smoothly from the exhaust valve, the so-called transverse crack in which the side wall of the outer can is cracked may occur. For example, in a battery module, when a transverse crack occurs in the outer can, heat is transmitted to nearby batteries and the like through the high-temperature gas. Therefore, suppressing the transverse crack of the outer can becomes an important issue. As a result of in-depth research conducted by the inventors of the present application, it was found that since the generated gas does not reach the exhaust valve but fills the interior of the battery, the electrode body is pushed against the exhaust valve, the exhaust valve is blocked, and the internal pressure cannot be released, which easily causes the transverse crack of the outer can. Patent document 1 does not study the blockage of the exhaust valve, and there is still room for improvement.

[0007] An object of the present disclosure is to provide a sealed battery capable of suppressing rupture of a side wall portion of an outer can.

[0008] A sealed battery as one embodiment of the present invention comprises: a bottomed cylindrical outer can having an opening; a sealing body that blocks the opening; and a wound electrode body that is accommodated in the outer can, an exhaust valve being provided at the bottom of the outer can and at one of the sealing body, one of two end portions in the winding axial direction of the outermost peripheral end of the electrode body that is closer to the exhaust valve is fixed by a first fixing member, and the other that is farther from the exhaust valve is fixed by a second fixing member, and a value obtained by dividing the thermal conductivity of the first fixing member in the thickness direction by the volume of the first fixing member is smaller than a value obtained by dividing the thermal conductivity of the second fixing member in the thickness direction by the volume of the second fixing member.

[0009] As another embodiment of the present invention, a sealed battery comprises: a bottomed cylindrical outer can having an opening; a sealing body that blocks the opening; and a wound electrode body that is accommodated in the outer can, exhaust valves being provided on both the bottom of the outer can and the sealing body, and when the exhaust valve having a larger area is set as the first exhaust valve and the exhaust valve having a smaller area is set as the second exhaust valve, one of the two end portions in the winding axial direction of the outermost peripheral end of the electrode body that is closer to the first exhaust valve is fixed by a first fixing member, and the other that is closer to the second exhaust valve is fixed by a second fixing member, and a value obtained by dividing the thermal conductivity of the first fixing member in the thickness direction by the volume of the first fixing member is smaller than a value obtained by dividing the thermal conductivity of the second fixing member in the thickness direction by the volume of the second fixing member.

[0010] According to the sealed battery as one aspect of the present disclosure, it is possible to suppress the rupture of the side wall portion of the outer can. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 1 is an axial cross-sectional view showing a cylindrical battery as an example of an embodiment.

[0012] Figure 2 yes Figure 1 A perspective view of an electrode body included in a cylindrical battery shown in FIG.

[0013] Figure 3 This is an axial cross-sectional view of a cylindrical battery as another example of the embodiment.

[0014] Figure 4 yes Figure 2 A perspective view of an electrode body included in a cylindrical battery shown in FIG. DETAILED DESCRIPTION

[0015] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The embodiments described below are only examples, and the present disclosure is not limited to the following embodiments. The shapes, materials, numbers, etc. shown below are examples and can be appropriately changed according to the specifications of the sealed battery. In addition, in the following, in all the drawings, the same figure marks are given to equivalent elements, and repeated descriptions are omitted. In the second embodiment, the description of the same effects and modifications as the first embodiment is omitted.

[0016] <First embodiment>

[0017] Below, refer to Figure 1 as well as Figure 2 A cylindrical battery 10 as an example of the embodiment will be described.

[0018] Figure 12 is an axial cross-sectional view of the cylindrical battery 10. In the cylindrical battery 10, the sealing body 30 side (the opening side of the outer can 20) is set as the top, and the bottom 20A side of the outer can 20 is set as the bottom. Figure 1 As shown, the cylindrical battery 10 comprises: a bottomed cylindrical outer can 20 having an opening at the top; a sealing body 30 that blocks the opening; and a wound electrode body 14. The electrode body 14 is housed in the outer can 20 so that the winding axis is substantially parallel to the vertical direction of the outer can 20.

[0019] The electrode body 14 includes a positive electrode 11, a negative electrode 12, and a separator 13, and has a structure in which the positive electrode 11 and the negative electrode 12 are spirally wound with the separator 13 interposed therebetween. The positive electrode 11, the negative electrode 12, and the separator 13 are all formed in a strip shape, and are spirally wound around a winding core arranged along a winding axis, so as to be alternately stacked in the radial direction of the electrode body 14.

[0020] The positive electrode 11, for example, has a positive electrode core and a positive electrode mixture layer formed on at least one surface of the core. For the positive electrode core, a foil of a metal such as aluminum or aluminum alloy that is stable within the potential range of the positive electrode 11, a film that arranges the metal on the surface, etc. can be used. The positive electrode mixture layer contains a positive electrode active material, a conductive agent such as acetylene black, and a binder such as polyvinylidene fluoride, and is preferably formed on both sides of the positive electrode core. For the positive electrode active material, for example, a lithium transition metal composite oxide is used. A positive electrode mixture slurry containing a positive electrode active material, a conductive agent, and a binder is applied to the positive electrode core, and after the coating is dried, the coating is rolled to form the positive electrode mixture layer on both sides of the core, thereby manufacturing the positive electrode 11.

[0021] The negative electrode 12, for example, has a negative electrode core and a negative electrode mixture layer formed on at least one surface of the core. For the negative electrode core, a foil of a metal such as copper or copper alloy that is stable within the potential range of the negative electrode 12, a film in which the metal is arranged on the surface, etc. can be used. The negative electrode mixture layer contains a negative electrode active material and a binder such as styrene-butadiene rubber (SBR), and is preferably formed on both surfaces of the negative electrode core. For the negative electrode active material, for example, graphite, silicon-containing compounds, etc. are used. A negative electrode mixture slurry containing a negative electrode active material, a binder, etc. is applied to the negative electrode core, and after the coating is dried, the coating is rolled to form the negative electrode mixture layer on both surfaces of the core, thereby manufacturing the negative electrode 12.

[0022] For the separator 13, for example, a porous sheet having ion permeability and insulation is used. Specific examples of the porous sheet include microporous films, woven fabrics, nonwoven fabrics, etc. As the material of the separator, olefin resins such as polyethylene and polypropylene, cellulose, etc. are suitable. The separator 13 can also be a laminate having a cellulose fiber layer and a thermoplastic resin fiber layer such as an olefin resin. In addition, it can be a multilayer separator including a polyethylene layer and a polypropylene layer, and it can also be a component coated with a material such as an aramid resin, ceramics, etc. on the surface of the separator 13.

[0023] The cylindrical battery 10 has insulating plates 15 and 16 disposed above and below the electrode body 14, respectively. Figure 1 In the example shown, the positive electrode lead 17 connected to the positive electrode 11 extends to the sealing body 30 side through the through hole of the insulating plate 15, and the negative electrode lead 18 connected to the negative electrode 12 extends to the bottom 20A side of the outer can 20 through the outside of the insulating plate 16. The positive electrode lead 17 is connected to the bottom surface of the terminal portion 32 of the sealing body 30 by welding or the like, and the sealing body 30 serves as the positive electrode external terminal. The negative electrode lead 18 is connected to the inner surface of the bottom 20A of the outer can 20 by welding or the like, and the outer can 20 serves as the negative electrode external terminal.

[0024] The outer can 20 includes a bottom 20A and a side wall 20B, and is a metal container with a bottom cylindrical shape. The bottom 20A is in the shape of a disk, and the side wall 20B is formed in a cylindrical shape along the outer peripheral edge of the bottom 20A. Regarding the groove portion 20C, a part of the side wall 20B extends inward near the opening of the outer can 20, and is formed in a ring shape along the circumference of the outer can 20. The riveted portion 20D is formed in a ring shape along the circumference of the outer can 20 at the opening end.

[0025] The outer can 20 contains an electrolyte in addition to the electrode body 14. For the electrolyte, for example, a non-aqueous electrolyte is used. The non-aqueous electrolyte contains a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. For the non-aqueous solvent, esters, ethers, nitriles, amides, and mixed solvents of two or more thereof can be used. The non-aqueous solvent may also contain a halogen-substituted body obtained by replacing at least a part of the hydrogen of these solvents with a halogen atom such as fluorine. In addition, the non-aqueous electrolyte is not limited to a liquid electrolyte, but may also be a solid electrolyte. For the electrolyte salt, for example, a lithium salt such as LiPF6 is used. The type of electrolyte is not particularly limited, and an aqueous electrolyte may also be used.

[0026] The sealing body 30 is fixed to the opening of the outer can 20 by caulking through the gasket 21. Specifically, the sealing body 30 is supported by the groove 20C of the outer can 20 and is fixed by caulking at the caulking portion 20D of the outer can 20.

[0027] The sealing body 30 is formed into a substantially disk shape in a plan view, and is made, for example, by stamping a plate of aluminum or aluminum alloy. The sealing body 30 functions as a gas exhaust valve for exhausting gas inside the cylindrical battery 10 when the internal pressure of the cylindrical battery 10 increases in the event of an abnormality of the cylindrical battery 10 .

[0028] The sealing body 30 includes a flange portion 31 fixed by caulking to the opening of the outer can 20 , a terminal portion 32 formed radially inward of the flange portion 31 , and a thin-walled portion 33 connecting the flange portion 31 and the terminal portion 32 .

[0029] The flange 31 is supported by the groove 20C of the outer can 20 and is fixed by riveting 20D of the outer can 20. The flange 31 is formed in an annular shape. The upper part of the inner peripheral surface of the flange 31 is connected to the outer end 33B of the thin wall part 33.

[0030] The terminal portion 32 is a portion joined to the positive lead 17 and serves as a positive internal terminal. When a plurality of cylindrical batteries 10 are formed into a battery pack, a lead plate can be joined to the upper surface of the terminal portion 32 in order to connect the cylindrical batteries 10 to each other. The terminal portion 32 is formed in a substantially circular plate shape. The lower portion of the outer peripheral surface of the terminal portion 32 is connected to the inner end portion 33A of the thin-walled portion 33.

[0031] As described above, the thin-walled portion 33 is a portion connecting the terminal portion 32 and the flange portion 31. The thin-walled portion 33 is formed in an annular shape. The thin-walled portion 33 is formed to be inclined upward from the radial inner side to the outer side of the sealing body 30. In addition, the thin-walled portion is formed to be tapered from the radial inner side to the outer side of the sealing body. The thin-walled portion 33 is formed so that the thickness (length in the vertical direction) of the outer end portion 33B is smaller than that of the inner end portion 33A, and the thickness of the outer end portion 33B is the smallest.

[0032] The thin-walled portion 33 is a portion that breaks when the internal pressure of the cylindrical battery 10 rises. When the internal pressure of the cylindrical battery 10 rises, the sealing body 30 is pressed upward by the pressure of the gas, and the thin-walled portion 33 is reversed from a state of being tilted upward toward the outside from the radial inside to a state of being tilted downward, and the outer end 33B of the thin-walled portion 33 breaks, forming a gas discharge port.

[0033] Next, refer to Figure 2 The electrode body 14 will be described. Figure 2 1 is a perspective view of the electrode body 14. As described above, the electrode body 14 has a winding structure in which the positive electrode 11 and the negative electrode 12 are wound in a spiral shape with the separator 13 interposed therebetween. The positive electrode lead 17 extends axially from the upper end of the electrode body 14 from a substantially middle position in the radial direction of the electrode body 14. In addition, the negative electrode lead 18 extends axially from the radially outer position of the electrode body 14 at the lower end of the electrode body 14.

[0034] The upper and lower ends of the outermost peripheral end 14A of the electrode body 14 are fixed by the first fixing member 40 and the second fixing member 42 (hereinafter, the first fixing member 40 and the second fixing member 42 are sometimes collectively referred to as the fixing members 40 and 42). In the present embodiment, the separator 13 is exposed at the outermost periphery of the electrode body 14, and the outermost peripheral end 14A is the end of the winding end side of the separator 13. In addition, the negative electrode 12 may also be exposed at the outermost periphery of the electrode body 14. The fixing members 40 and 42 are members for fixing the outermost peripheral end 14A to the electrode body 14, and are pasted to cover at least a portion of the outermost peripheral end 14A. In addition, the fixing members 40 and 42 only need to fix the two ends of the outermost peripheral end 14A in the winding axis direction (the upper and lower ends and their vicinity, for example, the range of 25% of the height of the winding axis direction of the electrode body 14 from the upper and lower ends), and the present disclosure is not limited to the case of fixing the upper and lower ends of the outermost peripheral end 14A.

[0035] In the present embodiment, the length of the fixing members 40 and 42 is substantially the same as the circumference (the length of one circumference) of the outermost peripheral surface of the electrode body 14, and one end of the long side direction of the fixing members 40 and 42 is connected to the other end. In addition, the length of the fixing members 40 and 42 may be shorter than the length of the outermost periphery of the electrode body 14 so that one end of the long side direction of the fixing members 40 and 42 does not overlap with the other end, or the length of the fixing members 40 and 42 may be longer than the length of the outermost periphery of the electrode body 14 so that one end of the long side direction of the fixing members 40 and 42 overlaps with the other end.

[0036] The width of each fixing member 40, 42 is, for example, less than 25% of the axial height of the electrode body 14. The lower limit of the width of each fixing member 40, 42 is preferably 3% relative to the axial height of the electrode body 14, and more preferably 5%. The width of each fixing member 40, 42 is, for example, 3 mm to 30 mm, or 5 mm to 15 mm. In addition, the thickness of the fixing members 40, 42 is, for example, 20 μm to 200 μm, or 50 μm to 100 μm.

[0037] The fixing members 40 and 42 are, for example, adhesive tapes having a base layer and an adhesive layer. The base layer can be appropriately selected from the viewpoints of strength, resistance to electrolyte, processability, cost, etc., and for example, PP (polypropylene), PI (polyimide), PET (polyethylene terephthalate), PPS (polyphenylene sulfide), etc. can be used. The adhesive layer is preferably a resin having adhesiveness at room temperature, and for example, an acrylic resin or a rubber resin can be used.

[0038] In the present embodiment, an exhaust valve is provided on the bottom 20A of the outer can 20 and the sealing body 30 of the sealing body 30. That is, one of the two ends of the outermost peripheral end 14A of the electrode body 14 in the winding axial direction, which is close to the exhaust valve, is fixed by the first fixing member 40, and the other is fixed by the second fixing member 42 away from the exhaust valve. The thermal conductivity and thickness in the thickness direction of the first fixing member 40 and the second fixing member 42 satisfy the relationship of (thermal conductivity of the first fixing member 40) / (volume of the first fixing member 40)<(thermal conductivity of the second fixing member 42) / (volume of the second fixing member 42). Thus, the rupture of the side wall portion 20B of the outer can 20 can be suppressed. It is difficult for the portion to which the fixing member is fixed to dissipate heat in an abnormality. By making it more difficult for the fixing member provided on the side close to the exhaust valve to dissipate heat than the fixing member provided on the side away from the exhaust valve, thermal runaway occurs on the side close to the exhaust valve. In this way, since the thermal runaway can be controlled so that the starting point of the fire is near the exhaust valve, the generated gas is less likely to stay in the outer tank 20, and the lateral crack can be suppressed.

[0039] The thickness of the first fixing member 40 fixing the one of the two ends of the outermost peripheral end 14A of the electrode body 14 in the winding axial direction close to the exhaust valve may be greater than the thickness of the second fixing member 42 fixing the one away from the exhaust valve. That is, the thickness of the first fixing member 40 and the thickness of the second fixing member 42 may also satisfy the relationship of (thickness of the first fixing member 40)>(thickness of the second fixing member 42). For example, 1.1≤(thickness of the first fixing member 40) / (thickness of the second fixing member 42)≤2.

[0040] The area of ​​the first fixing member 40 fixing the one closer to the exhaust valve of the two ends of the outermost peripheral end 14A of the electrode body 14 in the winding axial direction may be larger than the area of ​​the second fixing member fixing the one farther from the exhaust valve. That is, the areas of the first fixing member 40 and the second fixing member 42 may satisfy the relationship of (area of ​​the first fixing member 40)>(area of ​​the second fixing member 42). For example, 1.1≤(area of ​​the first fixing member 40) / (area of ​​the second fixing member 42)≤3.

[0041] The thermal conductivity in the thickness direction of the first fixing member 40 that fixes the one closer to the exhaust valve among the two ends of the winding axial direction of the outermost peripheral end 14A of the electrode body 14 may be lower than the thermal conductivity in the thickness direction of the second fixing member 42 that fixes the one farther from the exhaust valve. That is, the thermal conductivity of the first fixing member 40 and the second fixing member may satisfy the relationship of (thermal conductivity of the first fixing member 40) < (thermal conductivity of the second fixing member 42). For example, PI may be used as the base material layer of the first fixing member 40, and PP may be used as the base material layer of the second fixing member 42.

[0042] The present disclosure is not limited to the first embodiment described above. A degassing valve may be provided at the bottom 20 of the outer can 20 instead of the sealing body 30. In this case, the first fixing member 40 is arranged at the lower side of the electrode body 14, and the second fixing member 42 is arranged at the upper side of the electrode body 14.

[0043] <Second embodiment>

[0044] Next, refer to Figure 3 as well as Figure 4 A cylindrical battery 10x as another embodiment will be described. In the following embodiments, the same reference numerals as those in the first embodiment are given to the same structures as those in the first embodiment, and the description thereof is omitted. In the following embodiments, the description of the same effects and modifications as those in the first embodiment is omitted.

[0045] Figure 3 This is an axial cross-sectional view of a cylindrical battery 10x as another example of an embodiment. The cylindrical battery 10x has a groove 50 at the bottom 20A of the outer can 20. If the internal pressure of the cylindrical battery 10x rises in an abnormal situation, the groove 50 breaks and the gas is discharged from the broken part. That is, in the cylindrical battery 10x, exhaust valves are provided on both the bottom 20A of the outer can 20 and the sealing body 30. The groove 50 is formed into an annular shape, for example, along the circumference of the outer can 20. The depth of the groove 50 is, for example, 0.3 to 0.7 times the thickness of the bottom 20A excluding the groove 50.

[0046] In this embodiment, the diameter D2 of the circle formed by the groove 50 is larger than the diameter D1 of the circle formed by the outer end portion 33B. That is, the area of ​​the exhaust valve provided in the bottom portion 20A is larger than the area of ​​the exhaust valve provided in the sealing body 30 .

[0047] When the exhaust valve with a larger area is set as the first exhaust valve and the exhaust valve with a smaller area is set as the second exhaust valve, Figure 4As shown, one of the two ends of the outermost peripheral end 14A of the electrode body 14x in the winding axial direction is fixed by the first fixing member 40, and the other is fixed by the second fixing member 42. The value obtained by dividing the thermal conductivity of the first fixing member 40 in the thickness direction by the volume of the first fixing member 40 is smaller than the value obtained by dividing the thermal conductivity of the second fixing member 42 in the thickness direction by the volume of the second fixing member 42. In this embodiment, the first exhaust valve is provided at the bottom 20A of the outer can 20, and the second exhaust valve is provided at the sealing body 30. The thermal conductivity and volume of the first fixing member 40 and the second fixing member 42 in the thickness direction satisfy the relationship of (thermal conductivity of the first fixing member 40) / (volume of the first fixing member 40)<(thermal conductivity of the second fixing member 42) / (volume of the second fixing member 42). As a result, the rupture of the side wall portion 20B of the outer can 20 can be suppressed. By making it more difficult for the fixing member disposed near the first exhaust valve to dissipate heat than the fixing member disposed near the second exhaust valve, thermal runaway is caused on the side close to the first exhaust valve. In this way, since the thermal runaway can be controlled so that the starting point of the fire is near the first exhaust valve having a larger area, the generated gas is less likely to be retained in the outer tank 20, and the horizontal crack can be suppressed.

[0048] The thickness of the first fixing member 40 fixing the one of the two ends of the outermost peripheral end 14A of the electrode body 14x in the winding axial direction close to the first exhaust valve may be greater than the thickness of the second fixing member 42 fixing the one close to the second exhaust valve. That is, the thicknesses of the first fixing member 40 and the second fixing member 42 may satisfy the relationship of (thickness of the first fixing member 40)>(thickness of the second fixing member 42). For example, 1.1≤(thickness of the first fixing member 40) / (thickness of the second fixing member 42)≤2.

[0049] The area of ​​the first fixing member 40 fixing the one of the two ends of the outermost peripheral end 14A of the electrode body 14x closer to the first exhaust valve may be larger than the area of ​​the second fixing member 42 fixing the one closer to the second exhaust valve. That is, the areas of the first fixing member 40 and the second fixing member 42 may satisfy the relationship of (area of ​​the first fixing member 40)>(area of ​​the second fixing member 42). For example, 1.1≤(area of ​​the first fixing member 40) / (area of ​​the second fixing member 42)≤3.

[0050] The thermal conductivity in the thickness direction of the first fixing member 40 fixing the one of the two ends of the outermost peripheral end 14A of the electrode body 14x that is closer to the first exhaust valve may be lower than the thermal conductivity in the thickness direction of the second fixing member 42 fixing the one that is closer to the second exhaust valve. That is, the thermal conductivity in the thickness direction of the first fixing member 40 and the second fixing member may satisfy the relationship of (thermal conductivity of the first fixing member 40) < (thermal conductivity of the second fixing member 42). For example, PP may be used as the base material layer of the second fixing member 42, and PI may be used as the base material layer of the first fixing member 40.

[0051] The present disclosure is not limited to the second embodiment described above. The area of ​​the exhaust valve provided at the bottom 20A may be smaller than the area of ​​the exhaust valve provided at the sealing body 30. In this case, the exhaust valve provided at the bottom 20A becomes the second exhaust valve, and the exhaust valve provided at the sealing body 30 becomes the first exhaust valve. In addition, the first fixing member 40 is arranged on the upper side of the electrode body 14x, and the second fixing member 42 is arranged on the lower side of the electrode body 14x.

[0052] As described above, according to the sealed battery of the present disclosure, it is possible to suppress the rupture of the side wall portion of the outer can.

[0053] The present disclosure is further illustrated by the following embodiments.

[0054] Structure 1:

[0055] A sealed battery comprises: a bottomed cylindrical outer can having an opening; a sealing body that blocks the opening; and a wound electrode body that is accommodated in the outer can, an exhaust valve being provided at the bottom of the outer can and at either the sealing body, one of two end portions in the winding axial direction of the outermost peripheral end of the electrode body that is closer to the exhaust valve is fixed by a first fixing member, and the other that is farther from the exhaust valve is fixed by a second fixing member, and a value obtained by dividing the thermal conductivity of the first fixing member in the thickness direction by the volume of the first fixing member is smaller than a value obtained by dividing the thermal conductivity of the second fixing member in the thickness direction by the volume of the second fixing member.

[0056] Structure 2:

[0057] In the sealed battery according to Structure 1, the thickness of the first fixing member is greater than the thickness of the second fixing member.

[0058] Structure 3:

[0059] In the sealed battery according to Structure 1 or Structure 2, the area of ​​the first fixing member is larger than the area of ​​the second fixing member.

[0060] Structure 4:

[0061] In the sealed battery according to any one of Structures 1 to 3, the thermal conductivity of the first fixing member in the thickness direction is lower than the thermal conductivity of the second fixing member in the thickness direction.

[0062] Structure 5:

[0063] A sealed battery comprises: a bottomed cylindrical outer can having an opening; a sealing body that blocks the opening; and a wound electrode body that is accommodated in the outer can, exhaust valves being provided on both the bottom of the outer can and the sealing body, and when one of the exhaust valves having a larger area is set as a first exhaust valve and one having a smaller area is set as a second exhaust valve, one of the two end portions in the winding axial direction of the outermost peripheral end of the electrode body that is closer to the first exhaust valve is fixed by a first fixing member, and one that is closer to the second exhaust valve is fixed by a second fixing member, and a value obtained by dividing the thermal conductivity of the first fixing member in the thickness direction by the volume of the first fixing member is smaller than a value obtained by dividing the thermal conductivity of the second fixing member in the thickness direction by the volume of the second fixing member.

[0064] Structure 6:

[0065] In the sealed battery according to Structure 5, the thickness of the first fixing member is greater than the thickness of the second fixing member.

[0066] Structure 7:

[0067] In the sealed battery according to Structure 5 or 6, the area of ​​the first fixing member is larger than the area of ​​the second fixing member.

[0068] Structure 8:

[0069] In the sealed battery according to any one of Structures 5 to 7, the thermal conductivity of the first fixing member in the thickness direction is lower than the thermal conductivity of the second fixing member in the thickness direction.

[0070] -Description of Reference Numerals-

[0071] 10, 10x sealed battery; 11 positive electrode; 12 negative electrode; 13 separator; 14, 14x electrode body; 14A outermost peripheral end; 15, 16 insulating plate; 17 positive electrode lead; 18 positive electrode lead; 20 outer can; 20A bottom; 20B side wall; 20C grooved portion; 20D riveted portion; 21 gasket; 30 sealing body; 31 flange portion; 32 terminal portion; 33 thin-walled portion; 33A inner end portion; 33B outer end portion; 40 first fixing member; 42 second fixing member; 50 engraved portion.

Claims

1. A sealed battery comprising: a bottomed cylindrical outer can having an opening; a sealing body that blocks the opening; and a wound electrode body that is accommodated in the outer can, A gas exhaust valve is provided at the bottom of the outer can or at one of the sealing body. Of the two ends of the outermost peripheral end of the electrode body in the winding axial direction, one close to the exhaust valve is fixed by a first fixing member, and one far from the exhaust valve is fixed by a second fixing member. A value obtained by dividing the thermal conductivity of the first fixing member in the thickness direction by the volume of the first fixing member is smaller than a value obtained by dividing the thermal conductivity of the second fixing member in the thickness direction by the volume of the second fixing member.

2. The sealed battery according to claim 1, wherein: The thickness of the first fixing member is greater than the thickness of the second fixing member.

3. The sealed battery according to claim 1, wherein: The area of ​​the first fixing member is larger than the area of ​​the second fixing member.

4. The sealed battery according to claim 1, wherein: The thermal conductivity of the first fixing member in the thickness direction is lower than the thermal conductivity of the second fixing member in the thickness direction.

5. A sealed battery comprising: a bottomed cylindrical outer can having an opening; a sealing body that blocks the opening; and a wound electrode body that is accommodated in the outer can, The bottom of the outer can and the sealing body are both provided with exhaust valves, and when the exhaust valve with a larger area is set as a first exhaust valve and the exhaust valve with a smaller area is set as a second exhaust valve, Of the two ends of the outermost peripheral end of the electrode body in the winding axial direction, one close to the first exhaust valve is fixed by a first fixing member, and one close to the second exhaust valve is fixed by a second fixing member. A value obtained by dividing the thermal conductivity of the first fixing member in the thickness direction by the volume of the first fixing member is smaller than a value obtained by dividing the thermal conductivity of the second fixing member in the thickness direction by the volume of the second fixing member.

6. The sealed battery according to claim 5, wherein: The thickness of the first fixing member is greater than the thickness of the second fixing member.

7. The sealed battery according to claim 5, wherein: The area of ​​the first fixing member is larger than the area of ​​the second fixing member.

8. The sealed battery according to claim 5, wherein: The thermal conductivity of the first fixing member in the thickness direction is lower than the thermal conductivity of the second fixing member in the thickness direction.

Images