JP2013030280A - Battery and battery manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery and the like, in which pressure inside a battery case is properly reduced.SOLUTION: In a battery 100, a possible range of a sufficient pulling yield strength Fa when a rubber plug part 183 is pulled under an atmospheric pressure Pa while an internal pressure of a battery case 110 is the atmospheric pressure Pa is designated as a first yield strength range AFa, and a possible range of a sufficient pulling yield strength Fb when the rubber plug part 183 is pulled under the atmospheric pressure Pa while an internal pressure of the battery case 110 is an initial internal pressure Pb is designated as a second yield strength range AFb, an inside diameter d of a cylindrical part 171 of a through hole 170, an outside diameter D of a maximum compression part 183p of the rubber plug part 183, and hardness H of the rubber plug part 183 are arranged so that the first yield strength range AFa is spaced from the second yield strength range AFb.

Description

  The present invention includes a battery case having a through hole, an electrode body housed in the battery case, and a sealing member having a rubber plug portion formed by sealing the through hole of the battery case from the outside of the battery case. It relates to batteries. Moreover, it is related with the manufacturing method of this battery.

  Conventionally, a battery case provided with a through hole such as a liquid injection hole for injecting an electrolyte, an electrode body accommodated in the battery case, and a rubber plug formed by sealing the through hole from the outside of the battery case A battery including a sealing member having a portion is known. Further, in this battery, in the state where the internal pressure of the battery case was reduced from the atmospheric pressure, the battery case was hermetically sealed by sealing the through hole with the rubber plug portion of the sealing member, and then the initial charge was performed. There is something.

  For example, Patent Literature 1 discloses such a battery (see the claims of Patent Literature 1, FIG. 1 and the like). By sealing the battery case in a state where the inside of the battery case is decompressed in this way, even when gas is generated in the battery case due to charge / discharge, such as during initial charging, the internal pressure of the battery case is increased early. Can be suppressed. Therefore, the battery can be used more safely over a long period of time.

JP 2001-256965 A

By the way, in a battery in which the battery case is hermetically sealed in a state where the inside of the battery case is decompressed, it is desired to inspect whether or not the inside of the battery case is appropriately decompressed. However, it is difficult to directly measure the internal pressure of the hermetically sealed battery case.
Therefore, instead of directly measuring the internal pressure of the battery case, a method is conceivable in which the thickness of the battery case is measured before and after sealing under reduced pressure, and the reduced pressure state in the battery case is estimated from the thickness difference. However, in this inspection method, if the battery case has a high rigidity, such as a thick battery case, it is difficult for the battery case to have a thickness difference before and after sealing. difficult. Alternatively, in the case of a battery with no gap between the battery case and the electrode body, even if the inside of the battery case is depressurized, the battery case is not recessed inward before and after sealing. I can't.

  Therefore, the inventors of the present invention, after sealing the battery case under reduced pressure, conducted a pull-out test in which the rubber plug portion was pulled out with a predetermined force, and the inside of the battery case was appropriately depressurized depending on whether or not the rubber plug portion was pulled out. It was considered to determine whether the product is a non-defective product or a defective product in which the internal pressure of the battery case has become atmospheric pressure for some reason. In this pull-out test, a battery in which the rubber plug portion is not pulled out is regarded as a non-defective product, and a battery in which the rubber plug portion is pulled out is determined as a defective product.

  By the way, the rubber plug portion is press-fitted into the through hole (liquid injection hole). For this reason, when the rubber plug portion is pulled out, the rubber plug portion also generates a frictional force between the rubber plug portion and the through hole in addition to the pulling force generated when the inside of the battery case is set to a negative pressure. This frictional force has a large variation. In the case of an individual with high frictional force, even if it is a defective product in which the internal pressure of the battery case is actually atmospheric pressure, the rubber plug part is not pulled out. In some cases, the battery could not be properly inspected.

  This invention is made | formed in view of this present condition, Comprising: It aims at providing the battery in which the inside of a battery case was pressure-reduced appropriately, and the manufacturing method of this battery.

  One aspect of the present invention for solving the above-described problem is a battery case having a through-hole communicating with the inside and outside of the battery case, an electrode body accommodated in the battery case, and a rubber-like elastic body. And a sealing member having a rubber plug portion that is press-fitted from the outside of the battery case and tightly plugs the through hole, and the internal pressure of the battery case before the initial charge is reduced from the atmospheric pressure Pa. As the initial internal pressure Pb, the battery plug is formed by sealing the through hole with the rubber plug portion and then performing the initial charging, and the through hole has a cylindrical portion whose inner peripheral surface forms a cylindrical shape, The rubber plug portion has a tapered portion that has a circular cross section perpendicular to the axial direction of the through-hole and has a tapered side surface that increases in diameter toward the outer side in the axial direction. The outer cylindrical edge that is the outer opening edge, the highest The inner diameter of the cylindrical portion of the through hole is d, and the maximum compression portion compressed to the maximum at the outer cylindrical edge of the taper portion of the rubber plug portion is compressed before compression. When the rubber plug part is pulled out under the atmospheric pressure Pa in a state where the outer diameter of the rubber plug part is D, the hardness of the rubber plug part is H, and the internal pressure of the battery case is the atmospheric pressure Pa, the rubber plug part The range in which the pulling-out strength Fa generated in the battery can be taken as the first yield strength range AFa, the internal pressure of the battery case as the initial internal pressure Pb, and after sealing the through hole with the rubber plug portion, before the initial charging, When the rubber cap portion is pulled out under Pa and the pulling proof strength Fb generated in the rubber plug portion can be taken as a second proof strength range AFb, the inner diameter d of the cylindrical portion and the outer diameter of the maximum compression portion D and the hardness H of the rubber plug portion, When the first proof stress range AFa and the second proof stress range AFb are separated from each other, and the threshold value Fs is a value between the first proof stress range AFa and the second proof stress range AFb, the battery After the internal pressure of the case is set to the initial internal pressure Pb and the through hole is sealed with the rubber plug portion, a pulling force Fh up to the threshold value Fs at atmospheric pressure Pa is applied to the rubber plug portion, and the rubber plug The battery is obtained by performing the initial charging on a battery in which the rubber plug part is not pulled out by trying to pull out the part.

  In this battery, the first proof stress range AFa and the second proof stress range AFb are separated from each other in terms of the inner diameter d of the cylindrical portion of the through hole, the outer diameter D of the maximum compression portion of the rubber plug portion, and the hardness H of the rubber plug portion. The size is to be. Then, after the internal pressure of the battery case is set to the initial internal pressure Pb and the through hole is tightly plugged with the rubber plug portion, the threshold value Fs (predetermined value between the first proof stress range AFa and the second proof stress range AFb is reached under the atmospheric pressure Pa. ) Is applied to the rubber plug portion to try to pull out the rubber plug portion, and the battery in which the rubber plug member is not pulled out is initially charged.

  When an attempt is made to pull out the rubber plug portion, the rubber plug portion is not pulled out in a good battery in which the inside of the battery case is appropriately decompressed. On the other hand, in the case of a defective battery in which the internal pressure of the battery case has become atmospheric pressure for some reason, the rubber plug portion is reliably pulled out, which can be eliminated. And the battery by which the rubber plug part was not pulled out and the initial charge was performed after that can be provided as a battery in which the inside of the battery case is appropriately decompressed.

Further, in the battery described above, the average value of the pullout strength Fa is Fav, the standard deviation is σa, and the first strength range AFa is
Fav-4σa ≦ Fa ≦ Fav + 4σa (1)
And the average value of the pulling strength Fb is Fbv, the standard deviation is σb, and the second strength range AFb is
Fbv-4σb ≦ Fb ≦ Fbv + 4σb Equation (2)
, The inner diameter d of the cylindrical portion, the outer diameter D of the maximum compression portion, and the hardness H of the rubber plug portion,
Fav + 4σa <Fbv-4σb (3)
And the threshold value Fs is
Fav + 4σa <Fs <Fbv-4σb Formula (4)
A battery satisfying this relationship is preferable.

  By defining the first proof stress range AFa and the second proof stress range AFb as in equations (1) and (2), assuming that a Gaussian distribution is assumed, the pullout proof strength Fa is theoretically 99.9937%. It is included in the first proof stress range AFa, and the pullout proof strength Fb is included in the second proof stress range AFa with a probability of 99.99937%. Accordingly, it is considered that the pullout proof strengths Fa and Fb are included in the first and second proof load ranges AFa and AFb for almost all the batteries that are actually produced, and thus the threshold value Fs can be set to an appropriate value. As a result, when the rubber plug portion is pulled out, defective products in which the internal pressure of the battery case becomes atmospheric pressure can be more reliably eliminated, and only good products whose pressure is appropriately reduced in the battery case can be more reliably selected.

  In addition, the average value Fav and standard deviation of the pulling strength Y are determined as σa, and the average value Fbv and standard deviation σb of the pulling strength Yb are determined. The first proof stress range AFa and the second proof stress range AFb can be separated from each other simply by selecting the outer diameter D and the hardness H of the rubber plug portion. Accordingly, the inner diameter d, the outer diameter D, and the hardness H can be easily and appropriately determined.

Further, in the battery described above, the inner diameter d of the cylindrical portion, the outer diameter D of the maximum compression portion, and the hardness H of the rubber plug portion are set as the average value Fav of the pullout strength Fa and the pullout strength Fb. The average value Fbv of
Fbv> 2Fav Formula (5)
It is preferable that the battery has a size that satisfies the above relationship.

  In this way, if the average value Fbv of the pulling strength Yb is set to a value exceeding twice the average value Fav of the pulling strength Y, the space between the average value Fbv and the average value Fav is sufficiently large. The distance between AFa and the second yield strength range AFb can be further increased. Thereby, when the threshold value Fs is appropriately selected and the rubber plug portion is pulled out, the rubber plug portion is more reliably connected to a defective battery whose internal pressure of the battery case has become atmospheric pressure for some reason. Pulled out. Therefore, it is possible to more reliably sort only the batteries whose pressure is appropriately reduced in the battery case.

Furthermore, in the battery described above, the inner diameter d (mm) of the cylindrical portion, the outer diameter D (mm) of the maximum compression portion, and the hardness H of the rubber plug portion (°, where the hardness H is According to the new JIS standard K6235, it is a value measured using a type A durometer as a hardness meter.) With respect to the initial internal pressure Pb (kPa)
| Pb | · π · d · D ² / (D ² −d ² )> 3.7 × 10 ² × H−8.1 × 10 ³ Formula (6)
It is preferable that the battery has a size that satisfies the above relationship.

  This expression (6) is a relational expression derived from the above-described expression (5), as will be described later. Therefore, the inner diameter d (mm) of the cylindrical portion 171, the outer diameter D (mm) of the maximum compression portion 183 p, and the hardness H (°) of the rubber plug member 183 are selected so as to satisfy Expression (6). Only the relationship of Formula (5) can be satisfied. Accordingly, the inner diameter d (mm), the outer diameter D (mm), and the hardness H (°) can be easily and appropriately determined.

  In another aspect, the battery case includes a battery case having a through-hole communicating with the inside and the outside of the battery case, an electrode body accommodated in the battery case, and a rubber-like elastic body. A sealing member having a rubber plug portion that is press-fitted and tightly plugs the through hole, and the internal pressure of the battery case before the initial charge is set to an initial internal pressure Pb that is reduced from the atmospheric pressure Pa, and the rubber The through hole is hermetically plugged with a plug portion, and then the initial charging is performed. The through hole has a cylindrical portion whose inner peripheral surface is cylindrical, and the rubber plug portion is an axis of the through hole. An outer cylindrical end that is a circular cross-section perpendicular to the direction and has a tapered side surface that increases in diameter toward the outer side in the axial direction, and the tapered portion is an opening edge of the outer side of the cylindrical portion. At the edge, compressed to the highest compression rate, The inner diameter of the cylindrical portion is d, and the outer diameter of the maximum compression portion compressed at the outer cylindrical end edge of the taper portion of the rubber plug portion to the maximum is D, and the rubber plug portion A range in which the pulling strength Fa generated in the rubber plug portion can be obtained when the rubber plug portion is pulled out under the atmospheric pressure Pa in a state where the hardness is H and the internal pressure of the battery case is the atmospheric pressure Pa is a first range. When the rubber plug portion is pulled out under the atmospheric pressure Pa after the through hole is sealed with the rubber plug portion and the initial pressure is set, with the proof stress range AFa and the internal pressure of the battery case as the initial internal pressure Pb When the second yield strength range AFb is a range that can be taken by the pulling strength Fb generated in the rubber plug portion, the inner diameter d of the cylindrical portion, the outer diameter D of the maximum compression portion, and the hardness H of the rubber plug portion. The first proof stress range AFa and the second proof stress A method of manufacturing a battery having a size separated from the surrounding AFb, wherein the rubber plug portion of the sealing member is inserted into the through hole in a state where the internal pressure of the battery case is reduced to the initial internal pressure Pb. A sealing step of sealingly fitting the through hole by press-fitting from the outside and hermetically sealing the battery case, and the threshold value Fs is a value between the first proof stress range AFa and the second proof stress range AFb. Then, after the plugging step, a pulling test step for applying a pulling force Fh up to the threshold value Fs up to the threshold value Fs under the atmospheric pressure Pa to try to pull out the rubber plug portion, and the pulling test step And an initial charging step of performing the initial charging on the battery from which the rubber plug portion has not been pulled out.

  In this battery manufacturing method, in the plugging step, the internal pressure of the battery case is reduced to the initial internal pressure Pb, and after the through hole is sealed with the rubber plug portion, the pull-out test of the rubber plug portion is performed in the pull-out test step. Do. At that time, the rubber plug member is not pulled out in a non-defective battery in which the pressure inside the battery case is appropriately reduced. On the other hand, in a defective battery in which the internal pressure of the battery case has become atmospheric pressure for some reason, the rubber plug portion is reliably pulled out. Therefore, by sorting out the batteries from which the rubber plug portions have not been pulled out, it is possible to reliably sort out only the non-defective products in which the inside of the battery case is appropriately decompressed.

  In the pull-out test step, the threshold value Fs is set to a predetermined value between the first proof stress range AFa and the second proof stress range AFb, and the pulling force Fh up to the maximum threshold value Fs is applied to the rubber plug portion. As described above, since the rubber plug portion is press-fitted into the through-hole, when the rubber plug portion is pulled out, a frictional force is also generated between the rubber plug portion and the through-hole, but this frictional force may vary greatly. .

  However, by setting the threshold value Fs to a value exceeding the first proof stress range AFa, even if this friction force varies, the pulling force Fh exceeding the friction force can be applied to the rubber plug portion. If the battery is defective, the rubber plug is securely pulled out. On the other hand, by setting the threshold value Fs to a value lower than the second proof stress range AFb, even if the friction force varies, the rubber plug portion is not pulled out in a battery in which the inside of the battery case is appropriately decompressed. Therefore, it is possible to easily and reliably select only non-defective products in which the internal pressure of the battery case is appropriately reduced by eliminating defective products whose internal pressure in the battery case has become atmospheric pressure. Therefore, a battery in which the inside of the battery case is appropriately decompressed can be easily manufactured.

Furthermore, in the battery manufacturing method described above, the average value of the pullout strength Fa is Fav, the standard deviation is σa, and the first strength range AFa is
Fav-4σa ≦ Fa ≦ Fav + 4σa (1)
And the average value of the pulling strength Fb is Fbv, the standard deviation is σb, and the second strength range AFb is
Fbv-4σb ≦ Fb ≦ Fbv + 4σb Equation (2)
, The inner diameter d of the cylindrical portion, the outer diameter D of the maximum compression portion, and the hardness H of the rubber plug portion,
Fav + 4σa <Fbv-4σb (3)
And the threshold value Fs is
Fav + 4σa <Fs <Fbv-4σb Equation (4)
A battery manufacturing method with a value satisfying the above relationship is preferable.

  By defining the first proof stress range AFa and the second proof stress range AFb as in the formulas (1) and (2), if the Gaussian distribution is assumed, the pullout proof strength Fa is theoretically 99.9937%. The first yield strength range AFa is included, and the pullout yield strength Fb is included in the second yield strength range AFa with a probability of 99.99937%. Accordingly, it is considered that the pullout proof strengths Fa and Fb are included in the first and second proof load ranges AFa and AFb for almost all the batteries that are actually produced, and thus the threshold value Fs can be set to an appropriate value. As a result, when the rubber plug portion is pulled out, defective products in which the internal pressure of the battery case becomes atmospheric pressure can be more reliably eliminated, and only good products whose pressure is appropriately reduced in the battery case can be more reliably selected.

  In addition, the average value Fav and standard deviation of the pulling strength Y are determined as σa, and the average value Fbv and standard deviation σb of the pulling strength Yb are determined. The first proof stress range AFa and the second proof stress range AFb can be separated from each other simply by selecting the outer diameter D and the hardness H of the rubber plug portion. Accordingly, the inner diameter d, the outer diameter D, and the hardness H can be easily and appropriately determined.

Further, in the battery manufacturing method described above, the inner diameter d of the cylindrical portion, the outer diameter D of the maximum compression portion, and the hardness H of the rubber plug portion are set to the average value Fav of the pulling strength Fa and the The average value Fbv of the drawing strength Fb is
Fbv> 2Fav Formula (5)
A battery manufacturing method having a size satisfying the above relationship is preferable.

  In this way, if the average value Fbv of the pulling strength Yb is set to a value exceeding twice the average value Fav of the pulling strength Y, the space between the average value Fbv and the average value Fav is sufficiently large. The distance between AFa and the second yield strength range AFb can be further increased. Thereby, when the threshold value Fs is appropriately selected and the rubber plug portion is pulled out, the rubber plug portion is more reliably connected to a defective battery whose internal pressure of the battery case has become atmospheric pressure for some reason. Pulled out. Therefore, it is possible to more reliably sort only the batteries whose pressure is appropriately reduced in the battery case.

Furthermore, in the battery manufacturing method, the inner diameter d (mm) of the cylindrical portion, the outer diameter D (mm) of the maximum compression portion, and the hardness H (° of the rubber plug portion, where this hardness is H is a value measured using a type A durometer as a hardness meter in accordance with the new JIS standard K6235.) With respect to the initial internal pressure Pb (kPa)
| Pb | · π · d · D ² / (D ² −d ² )> 3.7 × 10 ² × H−8.1 × 10 ³ Formula (6)
A battery manufacturing method having a size satisfying the above relationship is preferable.

  This expression (6) is a relational expression derived from the above-described expression (5), as will be described later. Therefore, the inner diameter d (mm) of the cylindrical portion 171, the outer diameter D (mm) of the maximum compression portion 183 p, and the hardness H (°) of the rubber plug member 183 are selected so as to satisfy Expression (6). Only the relationship of Formula (5) can be satisfied. Accordingly, the inner diameter d (mm), the outer diameter D (mm), and the hardness H (°) can be easily and appropriately determined.

1 is a longitudinal sectional view showing a lithium ion secondary battery according to Embodiment 1. FIG. 1 is a perspective view showing an electrode body according to Embodiment 1. FIG. FIG. 3 is a partial plan view illustrating a state in which the positive electrode plate and the negative electrode plate are overlapped with each other via a separator according to the first embodiment. FIG. 3 is an exploded perspective view illustrating a case lid member, a positive electrode terminal, a negative electrode terminal, and the like according to the first embodiment. FIG. 4 is a partially enlarged longitudinal sectional view showing the vicinity of a liquid injection hole and a sealing member according to the first embodiment. FIG. 6 is a partially enlarged plan view showing the vicinity of the sealing member according to the first embodiment when viewed from above in FIG. 5. It is a longitudinal cross-sectional view which concerns on Embodiment 1 and shows a sealing member. FIG. 4 is a partially enlarged longitudinal sectional view showing the vicinity of a liquid injection hole of a case lid member according to the first embodiment. It is explanatory drawing which shows the mode of the pulling-out test process which tries pulling out of the rubber plug member by applying pulling force Fh to the rubber plug member of a sealing member regarding the manufacturing method of the lithium ion secondary battery which concerns on Embodiment 1. FIG. FIG. 6 is a partially enlarged longitudinal sectional view showing the vicinity of a liquid injection hole and a sealing member according to a modification of the first embodiment. It is a graph which shows the relationship between the rubber hardness H of a rubber stopper member, and the drawing strength F. It is a graph which shows the relationship between the compression rate C of the largest compression part of a rubber plug member, and the drawing strength F. It is a graph which shows the measurement result of the drawing strength F measured with the 10 samples, respectively about the battery which made the internal pressure of the battery case atmospheric pressure, and the battery in which the inside of the battery case was reduced appropriately. FIG. 6 is an explanatory diagram showing a hybrid vehicle according to a second embodiment. It is explanatory drawing which shows the hammer drill which concerns on Embodiment 3. FIG.

(Embodiment 1)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a lithium ion secondary battery (battery) 100 (hereinafter also simply referred to as battery 100) according to the first embodiment. 2 and 3 show a wound electrode body 120 constituting the battery 100 and a state in which the electrode body 120 is developed. FIG. 4 shows details of the case lid member 113, the positive terminal 150, the negative terminal 160, and the like. 5 and FIG. 6 show forms near the liquid injection hole (through hole) 170 and the sealing member 180. FIG. 1, 4, and 5, the upper side is the upper side of battery 100, and the lower side is the lower side of battery 100.

  The battery 100 is a square battery that is mounted on a vehicle such as a hybrid vehicle or an electric vehicle, or a battery-powered device such as a hammer drill. The battery 100 includes a rectangular parallelepiped battery case 110, a wound electrode body 120 accommodated in the battery case 110, a positive electrode terminal 150 and a negative electrode terminal 160 supported by the battery case 110 ( (See FIG. 1). In addition, a non-aqueous electrolyte solution 117 is held in the battery case 110.

  Of these, the battery case 110 is made of metal (aluminum in the first embodiment). The battery case 110 includes a box-shaped case main body member 111 that is open only on the upper side, and a case lid member 113 that is welded so as to close the opening 111h of the case main body member 111 (see FIG. 1 and FIG. 1). (See FIG. 4). The case lid member 113 has a rectangular plate shape having an inner main surface 113 c facing the inside of the battery case 110 and an outer main surface 113 d facing the outside of the battery case 110.

  The case lid member 113 is provided with a non-returnable safety valve 115 that breaks when the internal pressure of the battery case 110 reaches a predetermined pressure near the center in the longitudinal direction. Further, near the safety valve 115, a liquid injection hole (through hole) 170, which will be described later, is provided through the case lid member 113 and communicating between the inside and outside of the battery case 110. The liquid injection hole 170 is hermetically sealed (sealed) with a rubber plug member 183 of a sealing member 180 described later.

  In this battery 100, the inside of the battery case 110 is in a state (negative pressure) that is depressurized from the atmospheric pressure Pa (= 0 kPa). Specifically, as described later, the internal pressure (initial internal pressure Pb) of the battery case 110 at the time of sealing is Pb = −80 kPa, but gas is generated in the battery case 110 by conditioning (initial charge). The internal pressure (the internal pressure Pc at the time of shipment) of the battery case 110 at the time of shipment is about Pc = −50 kPa. In this specification, in principle, the shipping internal pressure Pc, the initial internal pressure Pb, and the like are described not by absolute pressure with reference to the absolute vacuum (zero point) but with gauge pressure with reference to the atmospheric pressure (zero point).

  The case lid member 113 is fixedly provided with a positive terminal 150 and a negative terminal 160 each composed of a current-carrying terminal member 151 and a bolt 153 via an insulating member 155 made of resin (FIGS. 1 and 4). reference). In the battery case 110, the positive terminal 150 is connected to the positive plate 121 (its positive current collecting part 121 m) of the electrode body 120, and the negative terminal 160 is connected to the negative plate 131 (its negative current collecting part 131 m) of the electrode body 120. (See FIG. 1).

  Next, the electrode body 120 will be described. The electrode body 120 is housed in an insulating film enclosure 119 formed in a bag shape having an insulating film opened only on the upper side, and is housed in the battery case 110 in a laid state (see FIG. 1). This electrode body 120 is obtained by rolling a belt-like positive electrode plate 121 and a belt-like negative electrode plate 131 to each other via a belt-like separator 141 (see FIG. 3), winding around an axis line AX, and compressing to a flat shape. Yes (see FIG. 2).

  The positive electrode plate 121 has a positive electrode current collector foil 122 made of a strip-shaped aluminum foil as a core material. On both main surfaces of the positive electrode current collector foil 122, the positive electrode active material layers 123 and 123 are strip-shaped in the longitudinal direction (left and right direction in FIG. 3) on a part extending in the longitudinal direction and extending in the longitudinal direction. Is provided. These positive electrode active material layers 123 and 123 are formed of a positive electrode active material, a conductive agent, and a binder.

  In the positive electrode plate 121, a belt-like portion where the positive electrode current collector foil 122 and the positive electrode active material layers 123 and 123 exist in the thickness direction of the positive electrode plate 121 is the positive electrode portion 121 w. In the state where the electrode body 120 is configured, the entire area of the positive electrode portion 121w is opposed to a later-described negative electrode portion 131w of the negative electrode plate 131 via the separator 141 (see FIG. 3). In addition, with the provision of the positive electrode part 121w on the positive electrode plate 121, one end part in the width direction (upward in FIG. 3) of the positive electrode current collector foil 122 extends in a band shape in the longitudinal direction, and has its own thickness. The positive electrode current collector portion 121m has no positive electrode active material layer 123 in the direction. A part of the positive electrode current collector 121m in the width direction protrudes from the separator 141 in a spiral shape to one side SA in the axis AX direction, and is connected to the positive electrode terminal 150 (see FIG. 1).

  Moreover, the negative electrode plate 131 has the negative electrode current collection foil 132 which consists of strip | belt-shaped copper foil as a core material. On both main surfaces of the negative electrode current collector foil 132, negative electrode active material layers 133 and 133 are band-like in the longitudinal direction (left and right direction in FIG. 3) on a portion extending in the longitudinal direction and extending in the longitudinal direction. Is provided. These negative electrode active material layers 133 and 133 are formed of a negative electrode active material, a binder, and a thickener.

  In the negative electrode plate 131, a strip-shaped portion where the negative electrode current collector foil 132 and the negative electrode active material layers 133 and 133 are present in the thickness direction of the negative electrode plate 131 is the negative electrode portion 131w. The entire area of the negative electrode portion 131 w faces the separator 141 in a state where the electrode body 120 is configured. In addition, as a result of providing the negative electrode portion 131w on the negative electrode plate 131, one end portion (downward in FIG. 3) in the width direction of the negative electrode current collector foil 132 extends in a band shape in the longitudinal direction and has its own thickness. The negative electrode current collector portion 131m has no negative electrode active material layer 133 in the direction. A part of the negative electrode current collector 131m in the width direction protrudes from the separator 141 toward the other side SB in the axis AX direction in a spiral shape, and is connected to the negative electrode terminal 160 (see FIG. 1).

  The separator 141 is a porous film made of resin, specifically, polypropylene (PP) and polyethylene (PE), and has a strip shape.

Next, the liquid injection hole 170 and the sealing member 180 will be described (see FIGS. 5 to 8).
The liquid injection hole 170 is a hole extending in the direction of the axis BX so as to penetrate between the inner main surface 113c and the outer main surface 113d of the case lid member 113 in order to inject the electrolytic solution 117 into the battery case 110. The inside and outside of the battery case 110 are communicated. The liquid injection hole 170 is located on the inner side BC (inside the battery, in FIG. 5 and FIG. 8, lower) in the direction of the axis BX, and is connected to the cylindrical portion 171 that opens to the inner main surface 113 c, It is formed of a tapered hole portion 173 that is located on the outer side BD in the direction of the axis BX (on the outside of the battery, upward in FIGS. 5 and 8) and opens to the outer main surface 113d.

The cylindrical portion 171 is configured by a cylindrical inner peripheral surface 171f having a cylindrical shape, from an inner cylindrical edge 171fc which is an opening edge of the inner BC to an outer cylindrical edge 171fd which is an opening edge of the outer BD. The inner diameter d is d = 2.20 mm.
In addition, the tapered hole portion 173 has a tapered shape in which a cross section perpendicular to the direction of the axis BX is circular and the outer BD has a larger diameter, and in the first embodiment, the side surface of the truncated cone whose diameter increases linearly as the outer BD increases. A tapered inner peripheral surface 173f is formed. The inner diameter of the inner tapered edge 173fc, which is the opening edge of the inner BC, of the tapered hole portion 173 is 2.20 mm, similar to the inner diameter d of the cylindrical portion 171, and the outer tapered end, which is the opening edge of the outer BD. The inner diameter of the edge 173fd is 2.30 mm.

  On the other hand, the sealing member 180 includes a covering member (covering portion) 181 and a rubber plug member (rubber plug portion) 183 joined thereto. Among these, the covering member 181 is made of the same material as that of the battery case 110, specifically, aluminum. The covering member 181 is parallel to the covering portion inner side surface 181c, which is a main surface located on the inner side CC (the case lid member 113 side, the lower side in FIGS. 5 and 7) of the sealing member 180 in the axis CX direction. A taper hole portion of the liquid injection hole 170, which has a covering portion outer surface 181 d that is a main surface located on the outer side CD in the axis CX direction (on the opposite side to the case lid member 113, the upper side in FIGS. 5 and 7). 173 (the outer tapered end edge 173fd) has a disk shape larger than the inner diameter.

  The covering member 181 covers the liquid injection hole 170 from the outer side BD in the axis BX direction, and is fixed to the battery case 110 (the case lid member 113) in a form coaxial with the liquid injection hole 170 (see FIG. 5). ). Specifically, an annular peripheral portion 181m along the outer peripheral edge of the covering member 181 is formed at four locations in the circumferential direction on an annular hole peripheral portion 113m surrounding the liquid injection hole 170 in the case lid member 113. Spot welded at equal intervals. As a result, four spot welds 181y, 181y,... Spaced apart from each other at equal intervals in the circumferential direction are formed, and the covering member 181 is fixed to the case lid member 113.

The rubber plug member 183 is made of a rubber-like elastic body, specifically, ethylene propylene diene rubber (EPDM) having a rubber hardness H of H = 50 °. The rubber hardness H is measured according to the new JIS standard K6235, and a type A durometer is used as the hardness meter.
The rubber plug member 183 has a truncated cone shape having a top surface 183c having a small diameter, a bottom surface 183d having a large diameter, and a side surface 183f connecting between them. The top surface 183c is smaller in diameter than the cylindrical portion 171 (inner diameter d) of the liquid injection hole 170. The bottom surface 183d is larger in diameter than the top surface 183c, larger in diameter than the cylindrical portion 171 (inner diameter d) of the liquid injection hole 170, and the outer tapered end of the taper hole portion 173 of the liquid injection hole 170. The diameter is smaller than the edge 173fd. In the first embodiment, the entire rubber plug member 183 corresponds to the aforementioned “tapered portion”.

  The bottom surface 183 d of the rubber plug member 183 is joined to the center of the covering portion inner side surface 181 c of the covering member 181, and is integrated with the covering member 181. The rubber plug member 183 extends from the inner surface 181c of the covering portion of the covering member 181 to the inner sides BC and CC in the directions of the axes BX and CX, and is inserted into the liquid injection hole 170. Then, the side surface 183f of the rubber plug member 183 is hermetically pressed to the boundary portion of the liquid injection hole 170 between the cylindrical inner peripheral surface 171f forming the cylindrical portion 171 and the tapered inner peripheral surface 173f forming the tapered hole portion 173. In this manner, the rubber plug member 183 is press-fitted into the liquid injection hole 170. As a result, the rubber plug member 183 has the highest compression rate C (C = 5.24% in the first embodiment) at the outer cylindrical end edge 171fd of the cylindrical portion 171 and the inner tapered end edge 173fc of the tapered hole portion 173. It is compressed. Of the rubber plug member 183, the outer diameter D before compression of the maximum compression portion 183p compressed to the maximum is D = 2.26 mm. Thus, the liquid injection hole 170 is tightly plugged with the rubber plug member 183.

In the present specification, the compression rate C (%) of the maximum compression unit 183p is obtained as follows. That is, the maximum compression unit 183p before compression (see FIG. 7) is an axis line CX direction perpendicular sectional area π × D ^2/4 of the transverse section of the, maximum compression unit 183p after compression (see FIG. 5) is , the cross-sectional area of the cross section perpendicular to the axis CX direction is π × d ^2/4. From this, the compression ratio C (%) was approximated as follows.
C = 100 × (π × D 2/4-π × d 2/4) / (π × D 2/4)
^{= 100 (D 2 -d 2)} / D 2 ... formula (7)

  In this battery 100, as will be described later, the internal pressure of the battery case 110 is set to an initial internal pressure Pb (Pb = −80 kPa in the first embodiment) reduced from the atmospheric pressure Pa before the initial charging. The liquid injection hole 170 is sealed with a rubber plug portion 183 of the stopper member 180, and the battery case 110 is hermetically sealed. Since gas is generated in the battery case 110 when the initial charging is performed, the internal pressure (shipping internal pressure Pc) of the battery case 110 after the initial charging (at the time of shipment) averages Pc = − as described above. 50 kPa.

  Next, a method for manufacturing the battery 100 will be described. First, a separately formed belt-like positive electrode plate 121 and negative electrode plate 131 are overlapped with each other via a belt-like separator 141 (see FIG. 3) and wound around an axis AX using a winding core. Thereafter, this is compressed into a flat shape to form the electrode body 120 (see FIG. 2).

  In addition, a case lid member 113 having a safety valve 115, a liquid injection hole 170, etc., an energizing terminal member 151 and a bolt 153 are prepared, and these are set in an injection mold. Then, the insulating member 155 is integrally formed by injection molding, and the positive electrode terminal 150 and the negative electrode terminal 160 are fixed to the case lid member 113 (see FIG. 4).

  Next, the positive electrode terminal 150 and the positive electrode current collector 121m of the electrode body 120 are connected (welded). Further, the negative electrode terminal 160 and the negative electrode current collector 131m of the electrode body 120 are connected (welded). Thereafter, a case main body member 111 and an insulating film enclosure 119 are prepared, the electrode body 120 is accommodated in the case main body member 111 via the insulating film enclosure 119, and an opening 111 h of the case main body member 111 is formed in the case lid member 113. Close with. Then, the case body member 111 and the case lid member 113 are welded by laser welding to form the battery case 110 (see FIG. 1).

  Separately, a sealing member 180 (see FIG. 7) composed of a covering member 181 and a rubber plug member 183 is formed. Specifically, the covering member 181 made of a metal plate is set in an injection molding die, and the rubber plug member 183 is integrally formed by injection molding.

  Next, the aforementioned battery is placed in a vacuum chamber, the inside of the vacuum chamber is decompressed, and the internal pressure of the battery case 110 is set to −90 kPa in the first embodiment. Then, a liquid injection nozzle is inserted into the liquid injection hole 170, and the electrolytic solution 117 is injected into the battery case 110 from the liquid injection nozzle. Thereafter, the periphery of the liquid injection hole 170 (hole peripheral portion 113m, etc.) is wiped and cleaned with a nonwoven fabric. The reason why the internal pressure (−90 kPa) of the battery case 110 is further reduced than the initial internal pressure Pb (Pb = −80 kPa in the first embodiment) described below is to quickly inject the electrolytic solution 117. is there.

  Next, in the sealing step, the battery case 110 is hermetically sealed under the condition of the initial internal pressure Pb = −80 kPa. That is, the rubber plug member 183 of the sealing member 180 is press-fitted into the liquid injection hole 170 from the outer side BD in the direction of the axis BX to seal the liquid injection hole 170, and the battery case 110 is hermetically sealed (FIG. 9). Thereafter, the inside of the vacuum chamber is returned to atmospheric pressure, and the battery is taken out from the vacuum chamber. Since the battery case 110 is hermetically sealed by the holding force due to the reduced pressure in the plugging step, the reduced pressure state is maintained even when the battery 100 is returned to the atmospheric pressure, and the internal pressure is about the initial internal pressure Pb = −80 kPa. It becomes.

Next, the drawing test process will be described. In the battery 100 according to the first embodiment, when the rubber plug member 183 is pulled out under the atmospheric pressure Pa in the state where the internal pressure of the battery case 110 is set to the atmospheric pressure Pa, the pull-out strength Fa (N ) Is a first proof stress range AFa (N), the first proof stress range AFa is 0.101 to 0.195N as will be described later.
In the battery 100, the internal pressure of the battery case 110 is set to the initial internal pressure Pb (Pb = −80 kPa in the first embodiment), the liquid injection hole 170 is sealed with the rubber plug member 183, and then the atmospheric pressure is set before the initial charge. Assuming that the pulling strength Fb (N) generated in the rubber plug member 183 when the rubber plug member 183 is pulled out under Pa is a second strength range AFb (N), the second strength range AFb is described later. As shown, it is 0.269 to 0.373N.

  Of these, the pulling strength Fa is determined as follows, for example. First, in the plugging step, the liquid injection hole 170 is sealed with the rubber plug member 183 of the sealing member 180 not under reduced pressure but under atmospheric pressure Pa, and the battery case 110 is hermetically sealed. Thereafter, the covering member 181 of the sealing member 180 is pulled toward the outer side BD, CD in the direction of the axis BX, CX, and an attempt is made to pull out the sealing member 180 (rubber plug member 183). At this time, the pull-out force Fh is gradually increased, and the pull-out force Fh when the rubber plug member 183 is pulled out from the liquid injection hole 170 is defined as the pull-out resistance Fa of the battery 100.

  In the first embodiment, the pulling strength Fa was measured for each of the 20 batteries 100. FIG. 13 shows a part of the measurement results of the pullout strength Fa (for 10 samples). As a result, the average value Fav of the pullout proof strength Fa was Fav = 0.1480N, and the standard deviation σa was σa = 0.118N.

Here, when the first proof stress range AFa is given by the above-described equation (1), the pullout proof strength Fa is theoretically included in the first proof stress range AFa with a probability of 99.99937%, assuming a Gaussian distribution. Therefore, it is considered that the pullout proof strength Fa is included in the first proof strength range AFa for almost all of the batteries 100 that are actually produced. Therefore, in the first embodiment, the first proof stress range AFa given by the expression (1) is set to a range that the pulling proof strength Fa (N) can take.
AFa: Fav−4σa ≦ Fa ≦ Fav + 4σa Formula (1)
By substituting Fav = 0.1480N and σa = 0.118N into this equation (1), the first proof stress range AFa is obtained as 0.101 to 0.195N as described above.

  Further, the pulling strength Fb is obtained as follows, for example. First, the sealing step is performed, and with the internal pressure of the battery case 110 set to the initial internal pressure Pb, the liquid injection hole 170 is sealed with the rubber plug member 183 of the sealing member 180, and the battery case 110 is hermetically sealed. Stop. Thereafter, the covering member 181 of the sealing member 180 is pulled toward the outer side BD, CD in the direction of the axis BX, CX, and an attempt is made to pull out the sealing member 180 (rubber plug member 183). At that time, the pull-out force Fh is gradually increased, and the pull-out force Fh when the rubber plug member 183 is pulled out from the liquid injection hole 170 is defined as the pull-out resistance Fb of the battery 100.

  In the first embodiment, the pulling strength Fb was measured for each of the 20 batteries 100. FIG. 13 shows a part of the measurement result of the pullout strength Fb (for 10 samples). As a result, the average value Fbv of the drawing strength Fb was Fbv = 0.210N, and the standard deviation σb was σb = 0.131N.

Here, when the second proof stress range AFb is given by the above-described formula (2), if the Gaussian distribution is assumed, the pullout proof strength Fb is theoretically included in the second proof stress range AFb with a probability of 99.99937%. Therefore, it is considered that the pullout proof strength Fb is included in the second proof stress range AFb for almost all the batteries 100 that are actually produced. Therefore, in the first embodiment, the second yield strength range AFb given by the expression (2) is set to a range that the pulling strength Fb (N) can take.
AFb: Fbv−4σb ≦ Fb ≦ Fbv + 4σb Equation (2)
By substituting Fbv = 0.210N and σb = 0.0131N into this equation (2), the second proof stress range AFb is obtained as 0.269 to 0.373N as described above.

  As described above, in the first embodiment, the first proof stress range AFa is 0.101 to 0.195N, and the second proof stress range AFb is 0.269 to 0.373N. They are separated (the ranges AFa and AFb do not overlap each other).

  Next, the threshold value Fs is set to a predetermined value between the first proof stress range AFa and the second proof stress range AFb. In the first embodiment, the threshold value Fs = 0.25N. Then, an attempt is made to pull out the rubber plug member 183 with the threshold value Fs as an upper limit. Specifically, the suction header is vacuum-sucked by the covering member 181 of the sealing member 180, and the suction header is pulled to the outer sides BD and CD in the directions of the axes BX and CX with the pull-out force Fh up to the threshold value Fs. Thus, the pulling force Fh is applied to the rubber plug member 183 to try to pull out the sealing member 180 (rubber plug member 183) (see FIG. 9). The degree of pressure reduction in the suction header is adjusted so that the suction header is separated from the sealing member 180 (its covering member 181) when the pull-out force Fh reaches the threshold value Fs. The pulling force Fh applied to the plug member 183) can be set to a maximum value up to the threshold value Fs. Alternatively, the degree of decompression in the suction header is sufficiently high, and the pulling force Fh applied to the sealing member 180 (rubber plug member 183) is changed to the threshold value Fs by directly controlling the force for lifting the suction header. Also good.

  At this time, the threshold value Fs exceeds the first proof stress range AFa. Therefore, even if the friction force generated between the rubber plug member 183 and the liquid injection hole 170 varies due to the press-fitting, the extraction exceeds the friction force. The force Fh can be applied to the sealing member 180 (rubber plug member 183). For this reason, the sealing member 180 (rubber plug member 183) is reliably pulled out from a defective product in which the internal pressure of the battery case 110 has become the atmospheric pressure Pa for some reason. On the other hand, since the threshold value Fs is a value lower than the second proof stress range AFb, even if the frictional force varies, a good product whose pressure inside the battery case 110 has been appropriately reduced is the sealing member 180 (rubber plug member 183). ) Is not pulled out. Therefore, defective products from which the sealing member 180 (rubber plug member 183) has been pulled out can be surely excluded, and only good products from which the sealing member 180 (rubber plug member 183) has not been pulled out can be reliably selected.

Next, in the welding process, the covering member 181 of the sealing member 180 is welded to the case lid member 113 for the selected good battery 100. Specifically, in a state where the covering member 181 of the sealing member 180 is pressed against the inner sides BC and DC in the directions of the axes BX and CX, the peripheral portion 181m of the covering member 181 is formed around the hole of the case lid member 113 by laser welding. Spot welding is performed at equal intervals at four locations in the circumferential direction at 113 m.
Thereafter, in the initial charging step (conditioning step), the selected non-defective battery 100 is initially charged. At that time, since gas is generated in the battery case 110, the internal pressure of the battery case 110 is, on average, from the initial internal pressure Pb = -80 kPa to the shipping internal pressure Pc = -50 kPa on average. Thus, the battery 100 is completed.

  Here, in the battery 100 according to the first embodiment, the initial internal pressure Pb (kPa), the inner diameter d (mm) of the cylindrical portion 171 of the liquid injection hole 170, and the outer diameter D of the maximum compression portion 183p of the rubber plug member 183. The relationship between (mm), the hardness H (°) of the rubber plug member 183, the first proof stress range AFa (N), and the second proof stress range AFb (N) will be described.

In the battery 100 according to the first embodiment, as shown in the graph of FIG. 13, the average value Fbv (= 0.3210N) of the pullout strength Fb is twice the average value Fav (= 0.1480N) of the pullout strength Fa. Therefore, the above equation (5) is established. Further, if the average value Fbv is set to a value exceeding twice the average value Fav in this way, the average value Fbv and the average value Fav can be sufficiently increased as shown in the graph of FIG. The first proof stress range AFa and the second proof stress range AFb can be greatly separated.
Fbv> 2Fav Formula (5)

By the way, when the rubber plug member 183 is pulled out from the liquid injection hole 170, the rubber plug member 183 is supplied with the pulling force Fd (N) generated by the negative pressure inside the battery case 110 and the rubber plug member 183. A friction force (= drawing strength Fa (N)) generated between the rubber plug member 183 and the liquid injection hole 170 is applied by being press-fitted into 170. Accordingly, the pulling strength Fb (N) is equal to the sum of the pulling force Fd (N) and the frictional force (= pulling strength Fa (N)).
Fb = Fd + Fa (8)
Further, the average value Fbv (N) of the pulling strength Fb is considered to be equal to the sum of the average value Fdv (N) of the pulling force Fd and the average value of the frictional force (= the average value Fav (N) of the pulling strength Fa). Therefore, the following equation (9) is established.
Fbv = Fdv + Fav Equation (9)

The average value Fdv (N) of the pull-in force Fd is the initial internal pressure Pb (kPa), the inner diameter d (mm) of the cylindrical portion 171 of the liquid injection hole 170, the absolute pressure p (= 101.325 kPa) of the atmospheric pressure Pa, 1 ( From (atm) = 101.325 (kPa) = 0.101325 (N / mm ² ) = p × 10 ⁻³ , it can be expressed by the following formula (10).
Fdv = (| Pb | / p ) × (π · d 2/4) × (p × 10 -3)
= | Pb | · π · d 2/4000 ... (10)

Further, when this equation (10) is substituted into the above equation (9), the following equation (11) is obtained.
Fbv = | Pb | · π · d 2/4000 + Fav ... formula (11)
The average value of the frictional force (= the average value Fav of the pull-out resistance Fa) is smaller than the average value Fdv of the pull-in force Fd. Further, in this equation (11), if the average value Fav of the pullout proof strength Fa is zero, the average value Fbv of the pullout proof strength Fb decreases accordingly.

The first proof stress range AFa and the second proof stress range AFb are separated from each other, that is, the minimum value (Fbv-4σb) of the second proof stress range AFb is made larger than the maximum value (Fav + 4σa) of the first proof stress range AFa. When thinking, if it calculates using Fbv given by following Formula (12) smaller than Fbv given by Formula (11), it can calculate in a safer direction. In other words, using the small Fbv given by equation (12), if the minimum value (Fbv-4σb) of the second proof stress range AFb is calculated to be larger than the maximum value (Fav + 4σa) of the first proof stress range AFa, Even in the larger Fbv given by the equation (11), the minimum value (Fbv−4σb) of the second proof stress range AFb is larger than the maximum value (Fav + 4σa) of the first proof stress range AFa. Therefore, for convenience, in Expression (11), the average value Fav of the pullout proof strength Fa is set to Fav = 0 (zero), and Expression (12) is used for the following calculation.
Fbv = | Pb | · π · d 2/4000 ... formula (12)

On the other hand, the average value of the frictional force (= average value Fav (N) of the pulling strength Fa) is the relational expression between the rubber hardness H (°) and the pulling strength F (N), the compression rate C (%), and the pulling strength. Using the relational expression with F (N), the constant k (1 / N), and the relational expression including the inner diameter d (mm) of the cylindrical portion 171, it can be expressed as follows.
Fav = (Relationship between rubber hardness H and pulling strength F) × (Relationship between compressibility C and pulling strength F) × (Constant k) × (Relationship including inner diameter d) Equation (13)

Among these, the relational expression between the rubber hardness H (°) and the pulling strength F (N) is obtained from the graph of FIG. 11 as follows.
F = 4.0 × 10 ⁻³ × H-9.0 × 10 ⁻² Formula (14)

  In addition, the graph of FIG. 11 was obtained from the following measurement result. That is, with respect to a plurality of batteries with different rubber hardness H, the pulling-out strength F (N) when the rubber plug member was pulled out under the atmospheric pressure Pa with the internal pressure of the battery case being set to the atmospheric pressure Pa was measured. The rubber hardness H was 50 °, 60 ° or 70 °. In this test, the inner diameter d of the cylindrical portion of the injection hole was d = 1.60 mm, and the compression ratio C of the maximum compression portion of the rubber plug member was C = 5.50%. The rest is the same as the battery 100 of the first embodiment.

Further, a relational expression between the compression rate C (%) and the pulling strength F (N) is obtained from the graph of FIG. 12 as follows.
F = 2.0 × 10 ⁻² × C (15)
Since the compression rate C (%) can be transformed to C = 100 (D ² −d ² ) / D ² as in the above-described equation (7), this is substituted into the equation (15).
F = 2.0 (D ² −d ² ) / D ² Formula (16)

  In addition, the graph of FIG. 12 was obtained from the following measurement result. That is, with respect to a plurality of batteries in which the compression ratio C of the maximum compression portion of the rubber plug member is changed, the pulling resistance strength F when the rubber plug member is pulled out under the atmospheric pressure Pa with the internal pressure of the battery case being set to the atmospheric pressure Pa. (N) was measured respectively. The compression rate C was 5.50% or 20.0%. In this test, the inner diameter d of the cylindrical portion of the liquid injection hole was d = 1.60 mm, and the rubber hardness of the rubber plug member was 50 °. The rest is the same as the battery 100 of the first embodiment.

Since both formula (14) and formula (16) are relational expressions derived from the experimental results with rubber hardness H = 50 ° and compression ratio C = 5.50%, in order to link these formulas, This is divided by the pull-out strength F = 0.11 (N), and this is set as a constant k (1 / N).
k = 1 / 0.11 Formula (17)
The relational expression including the inner diameter d is the following expression (18) because the results shown in FIGS. 11 and 12 are the experimental results when the inner diameter d = 1.60 mm.
(Relational formula including inner diameter d) = d / 1.6 Formula (18)

Next, when Expression (14) and Expression (16) to Expression (18) are substituted into Expression (13), the following Expression (19) is obtained.
Fav = (4.0 × 10 ⁻³ × H−9.0 × 10 ⁻² ) × (2.0 (D ² −d ² ) / D ² ) × (1 / 0.11) × (d / 1 .6) Formula (19)

Next, when the formula (12) and the formula (19) are substituted into the formula (5) and put together, the above-described formula (20) is obtained.
| Pb | · π · d · D ² / (D ² −d ² )> 3.7 × 10 ² × H−8.1 × 10 ³ Formula (6)
In addition, “3.7 × 10 ² ” on the right side of the equation (6) is obtained by rounding up the third digit to 2 significant digits so that it can be calculated in a safer direction. “× 10 ³ ” is obtained by rounding down the third digit to two significant digits so that it can be calculated more safely.

  In the battery 100 according to the first embodiment, as described above, the inner diameter d of the cylindrical portion 171 of the liquid injection hole 170 is d = 2.20 mm, and the outer diameter D of the maximum compression portion 183p of the rubber plug member 183 is D = 2. .26 mm, and the hardness H of the rubber plug member 183 is H = 50 °. Therefore, the relationship of Expression (6) is satisfied with respect to the initial internal pressure Pb = −80 kPa.

  As described above, the battery 100 according to the first embodiment includes the battery case 110 having the liquid injection hole (through hole) 170 that communicates the inside and the outside of the battery 100 and the electrode body 120 accommodated in the battery case 110. And a sealing member 180 having a rubber plug member (rubber plug portion) 183 that is made of a rubber-like elastic body and is press-fitted into the liquid injection hole 170 from the outside of the battery case 110 to seal the liquid injection hole 170 tightly. Prepare. Further, in this battery 100, the internal pressure of the battery case 110 before the initial charge is set to the initial internal pressure Pb that is reduced from the atmospheric pressure Pa, and the liquid injection hole 170 is sealed with the rubber plug member 183, and then the initial charge is performed. It becomes.

  Further, the liquid injection hole 170 has a cylindrical portion 171 having an inner peripheral surface 171f forming a cylindrical shape. Further, the rubber plug member 183 has a tapered portion forming a tapered side surface 183f having a circular cross section perpendicular to the axis BX direction of the liquid injection hole 170 and having a diameter larger toward the outer side BD in the axis BX direction (rubber plug member 183). The whole corresponds to the taper portion). The rubber plug member (tapered portion) 183 is compressed to the highest compression rate at the outer cylindrical end edge 171 fd which is the opening end edge of the outer side BD of the cylindrical portion 171.

  The inner diameter of the cylindrical portion 171 of the liquid injection hole 170 is d, and the outer diameter before compression of the maximum compression portion 183p of the rubber plug member (tapered portion) 183 that is compressed to the maximum at the outer cylindrical edge 171fd is D. The hardness of the rubber plug member 183 is H. Further, when the rubber plug member 183 is pulled out under the atmospheric pressure Pa with the internal pressure of the battery case 110 being set to the atmospheric pressure Pa, a range in which the pull-out strength Fa generated in the rubber plug member 183 can be taken is a first strength range AFa. And Further, when the internal pressure of the battery case 110 is set to the initial internal pressure Pb and the liquid injection hole 170 is sealed with the rubber plug member 183 and then the rubber plug member 183 is pulled out under the atmospheric pressure Pa before the initial charge, the rubber plug member A range that can be taken by the pulling-out strength Fb generated in 183 is defined as a second strength range AFb. Then, the inner diameter d of the cylindrical portion 171, the outer diameter D of the maximum compression portion 183 p, and the hardness H of the rubber plug member 183 are such that the first proof stress range AFa and the second proof stress range AFb are separated from each other.

  In the battery 100, when the threshold value Fs is a value between the first proof stress range AFa and the second proof stress range AFb, the internal pressure of the battery case 110 is set as the initial internal pressure Pb, and the liquid injection hole 170 is filled with the rubber plug member 183. The battery 100 in which the rubber plug member 183 was not pulled out by applying the pulling force Fh up to the threshold value Fs up to the threshold value Fs under the atmospheric pressure Pa to the rubber plug member 183 and trying to pull out the rubber plug member 183. The initial charge is applied.

  In the battery 100, the inner diameter d of the cylindrical portion 171 of the liquid injection hole 170, the outer diameter D of the maximum compression portion 183p of the rubber plug member 183, and the hardness H of the rubber plug member 183 are set to the first proof stress range AFa and the second. The proof stress range AFb is separated from each other. Then, the internal pressure of the battery case 110 is set to the initial internal pressure Pb, and the liquid injection hole 170 is tightly plugged with the rubber plug member 183, and then the maximum threshold value Fs (at the first proof stress range AFa and the second proof stress range AFb) under the atmospheric pressure Pa The battery 100 in which the rubber plug member 183 has not been pulled out by applying a pulling force Fh up to a value between the rubber plug member 183 and trying to pull out the rubber plug member 183 is subjected to initial charging.

  When trying to pull out the rubber plug member 183, the rubber plug member 183 is not pulled out from a good battery 100 in which the inside of the battery case 110 is appropriately decompressed. On the other hand, a defective battery whose internal pressure in the battery case 110 has become atmospheric pressure for some reason can be removed because the rubber plug member 183 is reliably pulled out. Then, the battery 100 according to the first embodiment in which the rubber plug member 183 is not pulled out and the initial charging is performed thereafter can be provided as a battery in which the inside of the battery case 110 is appropriately decompressed.

Furthermore, in the battery 100 according to the first embodiment, the average value of the pullout proof stress Fa is Fav, the standard deviation is σa, and the first proof stress range AFa is
Fav-4σa ≦ Fa ≦ Fav + 4σa (1)
The average value of the pulling strength Fb is Fbv, the standard deviation is σb, and the second strength range AFb is
Fbv-4σb ≦ Fb ≦ Fbv + 4σb Equation (2)
, The inner diameter d of the cylindrical portion 171, the outer diameter D of the maximum compression portion 183 p, and the hardness H of the rubber plug member 183,
Fav + 4σa <Fbv-4σb (3)
The size satisfies the relationship.
Also, the threshold value Fs is set to
Fav + 4σa <Fs <Fbv-4σb Equation (4)
The value satisfies the relationship.

  By defining the first proof stress range AFa and the second proof stress range AFb as shown in the equations (1) and (2) as described above, it is theoretically extracted with a probability of 99.9937% assuming a Gaussian distribution. The proof stress Fa is included in the first proof stress range AFa, and the pullout proof strength Fb is included in the second proof stress range AFa with a probability of 99.99937%. Accordingly, it is considered that the pullout proof strengths Fa and Fb are included in the first and second proof stress ranges AFa and AFb for almost all of the batteries 100 that are actually produced, and thus the threshold value Fs can be set to an appropriate value. . Thereby, when the rubber plug member 183 is pulled out, defective products whose internal pressure in the battery case 110 has become atmospheric pressure can be more reliably excluded, and only good products whose pressure in the battery case 110 is appropriately reduced can be more reliably selected.

  Further, the average value Fav and standard deviation of the pulling strength Fa are calculated as σa, and the average value Fbv and standard deviation σb of the pulling strength Fb are obtained, and the inner diameter d and the maximum compression of the cylindrical portion 170 are satisfied so that these satisfy the formula (3). The first proof stress range AFa and the second proof stress range AFb can be separated from each other only by selecting the outer diameter D of the portion 183p and the hardness H of the rubber plug member 183. Accordingly, the inner diameter d, the outer diameter D, and the hardness H can be easily and appropriately determined.

In the first embodiment, the inner diameter d of the cylindrical portion 171, the outer diameter D of the maximum compression portion 183 p, and the hardness H of the rubber plug member 183, the average value Fav of the pullout strength Fa and the average value Fbv of the pullout strength Fb. But,
Fbv> 2Fav Formula (5)
The size satisfies the relationship.

  In this way, if the average value Fbv of the pulling strength Yb is set to a value exceeding twice the average value Fav of the pulling strength Y, the space between the average value Fbv and the average value Fav is sufficiently large. The distance between AFa and the second yield strength range AFb can be further increased. Thereby, when the threshold value Fs is appropriately selected and the rubber plug member 183 is pulled out, a defective battery whose internal pressure of the battery case 110 has become atmospheric pressure for some reason is more reliably fixed. The member 183 is pulled out. Therefore, only the battery 100 in which the inside of the battery case 110 is appropriately decompressed can be more reliably selected.

In the present embodiment, as described above, the average value Fbv of the drawing strength Fb is set to a value exceeding twice the average value Fav of the drawing strength Fa, but the average value Fbv exceeds three times the average value Fav. It can also be a value or a value exceeding 4 times.
Fbv> 3Fav Formula (20)
Fbv> 4Fav Formula (21)

In the first embodiment, the inner diameter d (mm) of the cylindrical portion 171, the outer diameter D (mm) of the maximum compression portion 183 p, and the hardness H (° of the rubber plug member 183, provided that the hardness H According to JIS standard K6235, it is a value measured using a type A durometer as a hardness meter.) With respect to the initial internal pressure Pb (kPa)
| Pb | · π · d · D ² / (D ² −d ² )> 3.7 × 10 ² × H−8.1 × 10 ³ Formula (6)
The size satisfies the relationship.

  As described above, this expression (6) is a relational expression derived from expression (5). Therefore, the inner diameter d (mm) of the cylindrical portion 171, the outer diameter D (mm) of the maximum compression portion 183 p, and the hardness H (°) of the rubber plug member 183 are selected so as to satisfy Expression (6). Only the relationship of Formula (5) can be satisfied. Accordingly, the inner diameter d (mm), the outer diameter D (mm), and the hardness H (°) can be easily and appropriately determined.

  Further, in the manufacturing method of the battery 100 according to the first embodiment, the rubber plug member 183 of the sealing member 180 is made into the liquid injection hole (through hole) 170 in a state where the internal pressure of the battery case 110 is reduced to the initial internal pressure Pb. A sealing process is provided in which the liquid injection hole 170 is sealed by press-fitting from the outside BD, and the battery case 110 is hermetically sealed. Further, in this manufacturing method, when the threshold value Fs is a value between the first proof stress range AFa and the second proof stress range AFb, the pulling force Fh up to the maximum threshold value Fs under the atmospheric pressure Pa after the sealing step. Is pulled out on the rubber plug member 183, and a pull-out test step for trying to pull out the rubber plug member 183 is provided. Furthermore, this manufacturing method includes an initial charging step of performing initial charging on the battery 100 from which the rubber plug member 183 has not been pulled out in the pull-out test step.

  In the battery 100 manufacturing method, in the plugging step, after the liquid injection hole 170 is sealed with the rubber plug member 183 while the internal pressure of the battery case 110 is reduced to the initial internal pressure Pb, this rubber plug is used in the pull-out test step. A pull-out test of the member 183 is performed. At that time, the rubber plug member 183 is not pulled out of the non-defective battery 100 in which the pressure inside the battery case 110 is appropriately reduced. On the other hand, the rubber plug member 183 is reliably pulled out from a defective battery whose internal pressure in the battery case 110 has become atmospheric pressure for some reason. Therefore, by sorting out the batteries 100 from which the rubber plug member 183 has not been pulled out, it is possible to reliably sort out only the non-defective products in which the inside of the battery case 110 is appropriately decompressed.

  In the pull-out test step, the threshold value Fs is set to a predetermined value between the first proof stress range AFa and the second proof stress range AFb, and the pulling force Fh up to the maximum threshold value Fs is applied to the rubber plug member 183. As described above, since the rubber plug member 183 is press-fitted into the liquid injection hole 170, a frictional force is also generated between the rubber plug member 183 and the liquid injection hole 170 when the rubber plug member 183 is pulled out. In some cases, large variations may occur.

  However, by setting the threshold value Fs to a value exceeding the first proof stress range AFa, even if the friction force varies, the pulling force Fh exceeding the friction force can be applied to the rubber plug member 183. The rubber plug member 183 is reliably pulled out of a defective battery whose internal pressure is atmospheric pressure. On the other hand, by setting the threshold value Fs to a value lower than the second proof stress range AFb, even if the frictional force varies, the rubber plug member 183 is not pulled out in the battery 100 in which the inside of the battery case 110 is appropriately decompressed. Therefore, defective products whose internal pressure in the battery case 110 becomes atmospheric pressure can be excluded, and only good products whose pressure in the battery case 110 is appropriately reduced can be easily and reliably selected. Therefore, the battery 100 in which the inside of the battery case 110 is appropriately decompressed can be easily manufactured.

(Embodiment 2)
Next, a second embodiment will be described. A hybrid vehicle (vehicle) 700 (hereinafter also simply referred to as a vehicle 700) according to the second embodiment is equipped with the battery 100 according to the first embodiment, and the electric energy stored in the battery 100 is used as the drive energy of the drive source. It is used as a whole or a part (see FIG. 14).

  The automobile 700 is a hybrid automobile equipped with an assembled battery 710 in which a plurality of batteries 100 are combined and driven by using an engine 740, a front motor 720, and a rear motor 730 in combination. Specifically, the automobile 700 includes an engine 740, a front motor 720 and a rear motor 730, an assembled battery 710 (battery 100), a cable 750, and an inverter 760 on the vehicle body 790. The automobile 700 is configured to be able to drive the front motor 720 and the rear motor 730 using electrical energy stored in the assembled battery 710 (battery 100).

  As described above, the battery 100 is appropriately decompressed in the battery case 110 and can be used safely for a long time even if gas is generated in the battery case 110 during use (charging / discharging). Therefore, the performance and safety of the automobile 700 equipped with the same can be particularly improved.

(Embodiment 3)
Next, a third embodiment will be described. A hammer drill 800 according to the third embodiment is a battery-using device equipped with the battery 100 according to the first embodiment (see FIG. 15). In the hammer drill 800, a battery pack 810 including the battery 100 is accommodated in a bottom portion 821 of a main body 820, and the battery pack 810 is used as an energy source for driving the drill.

  As described above, the battery 100 is appropriately decompressed in the battery case 110 and can be used safely for a long time even if gas is generated in the battery case 110 during use (charging / discharging). Therefore, the performance and safety of the hammer drill 800 equipped with this can be particularly enhanced.

In the above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to the above-described first to third embodiments, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof. Yes.
For example, in the first embodiment, the liquid injection hole 170 for injecting the electrolytic solution 117 is exemplified as the “through hole” that communicates the inside and outside of the battery case. However, the through hole is not limited to the liquid injection hole. As the through hole, for example, a vent hole for venting gas in the battery case can be cited. In the first embodiment, the “through hole” is provided in the case lid member 113 of the battery case 110, but the formation position of the through hole is not limited to this. For example, the through hole may be provided on a side surface or a bottom surface of the case main body member 111.

  Moreover, in Embodiment 1, although the liquid injection hole 170 which consists of the cylindrical part 171 and the taper hole part 173 was illustrated as a "through-hole", the form of a through-hole is not restricted to this. For example, it is good also as a form which the whole through hole consists only of a cylindrical part. Further, as shown in FIG. 10, the through-hole (injection hole) 270 is connected to a cylindrical portion 271 having an inner peripheral surface 271f having a cylindrical shape and an outer side BD in the axial line BX direction of the cylindrical portion 271 and a side surface 273f1 is formed. It is good also as a form which consists of the cylindrical shape and the recessed part 273 where the bottom face 273f2 makes a plane.

  In the first embodiment, as the “electrode body”, the wound-type electrode body 120 in which the positive electrode plate 121 and the negative electrode plate 131 each having a band shape are wound on each other via the separator 141 is illustrated. The form of the body is not limited to this. For example, the electrode body may be a stacked type in which a plurality of positive and negative electrode plates each having a predetermined shape (for example, a rectangular shape) are alternately stacked via a separator.

  In Embodiment 1, the sealing member 180 in which the rubber plug member 183 is joined to the metal covering member 181 is illustrated as the “sealing member”, but the form of the sealing member is not limited thereto. For example, the sealing member may have a configuration in which the entire sealing member is formed only of a rubber plug member (a configuration in which the entire sealing member is formed of a rubber-like elastic body). In this case, since the sealing member cannot be welded to the battery case, the sealing member is fixed to the battery case only by press-fitting into the through hole. In the first embodiment, the covering member 181 and the rubber plug member 183 are integrated, but these may be separated.

  In the first embodiment, as the “rubber plug portion”, the rubber plug member 183 including only the tapered portion having the tapered side surface 183f and the truncated cone shape is illustrated, but the form of the rubber plug portion is limited to this. Not. For example, like a sealing member 280 shown in FIG. 10, a rubber plug member (rubber plug portion) 283 includes a tapered portion 285 having a tapered side surface 285f and a truncated cone shape, and an axis CX of the tapered portion 285. It is good also as a form which consists of the cylindrical part 286 which connects to the outer side CD of a direction, and makes a column shape. This rubber plug member 283 also has the highest taper portion 285 (its maximum compression portion 285p) at the opening edge (outer cylindrical edge 271fd) of the outer BD in the axis BX direction in the cylindrical portion 171 of the liquid injection hole 270. Compressed to compression rate.

  In the first embodiment, the rubber plug member 183 made of EPDM is exemplified as the “rubber plug portion”, but the material of the rubber-like elastic body forming the rubber plug portion is not limited thereto. Examples of the rubber-like elastic material include styrene butadiene rubber (SBR), nitrile rubber (NBR), polypropylene (PP), and perfluoroalkoxy fluororesin (PFA).

  In Embodiment 1, the covering member 181 is fixed to the battery case 110 by spot welding, but the fixing method is not limited to this. For example, the covering member 181 may be fixed to the battery case 110 by all-around welding. Further, the covering member 181 may be fixed to the battery case 110 using a brazing material or an adhesive.

In the first embodiment, the “first proof stress range AFa” is calculated from the average value Fav of the pullout proof strength Fa and the standard deviation σa.
Fav-4σa ≦ Fa ≦ Fav + 4σa (1)
However, it is not limited to this. The first proof stress range AFa is, for example,
Fav−6σa ≦ Fa ≦ Fav + 6σa
It is good. Further, the value of the pulling strength Fa obtained by measuring n (for example, 100) samples may be used as it is, and the minimum value to the maximum value may be defined as the first strength range AFa.

In the first embodiment, the “second proof stress range AFb” is calculated from the average value Fbv and standard deviation of the pulling proof strength Fb from σb.
Fbv-4σb ≦ Fb ≦ Fbv + 4σb Equation (2)
However, it is not limited to this. The second proof stress range AFb is, for example,
Fbv−6σb ≦ Fb ≦ Fav + 6σb
It is good. Alternatively, the value of the pulling strength Fb obtained by measuring n (for example, 100) samples may be used as it is, and the minimum value to the maximum value may be defined as the second strength range AFb.

  In the first embodiment, the threshold value Fs when the rubber plug member 183 is pulled out in the pull-out test process is set to Fs = 0.25N. However, the threshold value Fs is not limited to this value. The threshold value Fs may be appropriately selected from values between the first proof stress range AFa and the second proof stress range AFb. However, it is preferable that the threshold value Fs is a value closer to the lower limit value of the second proof stress range AFb than the upper limit value of the first proof stress range AFa. With such a threshold value Fs, the rubber plug member 183 is also pulled out in the pull-out test process even in the battery 100 in which the internal pressure of the battery case 110 is not atmospheric pressure, but the pressure reduction degree is extremely small for some reason. It is. Therefore, only the battery 100 in which the inside of the battery case 110 is more appropriately decompressed can be more reliably selected.

  Moreover, in Embodiment 2, although the hybrid vehicle 700 was illustrated as a vehicle carrying the battery 100 which concerns on this invention, it is not restricted to this. Examples of the vehicle on which the battery according to the present invention is mounted include an electric vehicle, a plug-in hybrid vehicle, a hybrid railway vehicle, a forklift, an electric wheelchair, an electrically assisted bicycle, and an electric scooter.

  Moreover, although Embodiment 3 illustrated the hammer drill 800 as a battery using apparatus which mounts the battery 100 which concerns on this invention in Embodiment 3, it is not restricted to this. Examples of battery-powered devices equipped with the battery according to the present invention include personal computers, mobile phones, battery-powered electric tools, uninterruptible power supply devices, various home appliances driven by batteries, office equipment, industrial equipment, etc. Is mentioned.

100 Lithium ion secondary battery (battery)
110 Battery case 111 Case body member 113 Case lid member 120 Electrode body 170, 270 Injection hole (through hole)
171, 271 Cylindrical portion 171 f Cylindrical inner peripheral surface (inner peripheral surface)
171fc Inner cylindrical edge 171fd Outer cylindrical edge 173 Tapered hole 180,280 Sealing member 181 Cover member (cover)
183 Rubber stopper member (Rubber stopper part, taper part)
283 Rubber stopper member (Rubber stopper part)
285 Tapered portion 286 Column portion 183p, 285p Maximum compression portion 700 Hybrid vehicle (vehicle)
710 battery pack 800 hammer drill (equipment using batteries)
810 Battery pack BX (injection hole) axis BC (in the injection hole axial direction) inner side BD (in the injection hole axial direction) outer side CX (in sealing member) axis CC (in the sealing member axial direction) ) Inner CD (in the axial direction of the sealing member) Outer d (Inner diameter of the cylindrical part of the injection hole) D Outer diameter (before compression of the maximum compression part of the rubber plug member)

Claims (8)

A battery case having a through-hole communicating with the inside and outside of itself;
An electrode body housed in the battery case;
A sealing member comprising a rubber-like elastic body, and having a rubber plug portion that is press-fitted into the through hole from the outside of the battery case and tightly plugs the through hole;
The internal pressure of the battery case before the initial charge is an initial internal pressure Pb reduced from the atmospheric pressure Pa, the battery plug is sealed with the through hole, and then the initial charge is performed,
The through hole has a cylindrical portion whose inner peripheral surface forms a cylindrical shape,
The rubber plug portion has a tapered portion forming a tapered side surface having a circular cross section perpendicular to the axial direction of the through hole and having a larger diameter toward the outer side in the axial direction,
The tapered portion is compressed to the highest compression rate at the outer cylindrical edge which is the outer opening edge of the cylindrical portion,
The inner diameter of the cylindrical portion of the through hole is d,
Of the taper portion of the rubber plug portion, the outer diameter before compression of the maximum compression portion compressed to the maximum at the outer cylindrical edge is D,
The rubber plug has a hardness of H,
With the internal pressure of the battery case set to atmospheric pressure Pa, when the rubber plug portion is pulled out under atmospheric pressure Pa, a range that can be taken by the pulling strength Fa generated in the rubber plug portion is a first strength range AFa,
When the internal pressure of the battery case is set to the initial internal pressure Pb, the rubber plug portion is sealed when the rubber plug portion is pulled out under an atmospheric pressure Pa after the through hole is sealed with the rubber plug portion and before the initial charging. When the range that can be taken by the pulling strength Fb that occurs in the second strength range AFb,
The inner diameter d of the cylindrical portion, the outer diameter D of the maximum compression portion, and the hardness H of the rubber plug portion are such that the first proof stress range AFa and the second proof stress range AFb are separated from each other,
When the threshold value Fs is a value between the first proof stress range AFa and the second proof stress range AFb,
After the internal pressure of the battery case is the initial internal pressure Pb and the through hole is sealed with the rubber plug portion,
Applying a pulling force Fh up to the threshold value Fs at the maximum under atmospheric pressure Pa to the rubber plug part, and trying to pull out the rubber plug part,
A battery obtained by performing the initial charging on a battery from which the rubber plug portion has not been pulled out. The battery according to claim 1,
The average value of the pullout proof strength Fa is Fav, the standard deviation is σa, and the first proof load range AFa is
Fav−4σa ≦ Fa ≦ Fav + 4σa,
The average value of the pullout proof strength Fb is Fbv, the standard deviation is σb, and the second proof stress range AFb is
When Fbv-4σb ≦ Fb ≦ Fbv + 4σb,
The inner diameter d of the cylindrical portion, the outer diameter D of the maximum compression portion, and the hardness H of the rubber plug portion,
Fav + 4σa <Fbv-4σb
As a size that satisfies the relationship
The threshold value Fs is
Fav + 4σa <Fs <Fbv-4σb
A battery that satisfies the above relationship. The battery according to claim 2,
The inner diameter d of the cylindrical portion, the outer diameter D of the maximum compression portion, and the hardness H of the rubber plug portion,
The average value Fav of the pullout strength Fa and the average value Fbv of the pullout strength Fb are:
Fbv> 2Fav
A battery that has a size that satisfies the above relationship. The battery according to claim 3,
The inner diameter d (mm) of the cylindrical portion, the outer diameter D (mm) of the maximum compression portion, and the hardness H (° of the rubber plug portion, where the hardness H is a hardness meter according to the new JIS standard K6235. Is a value measured using a type A durometer) with respect to the initial internal pressure Pb (kPa).
| Pb | · π · d · D ² / (D ² −d ² )> 3.7 × 10 ² × H−8.1 × 10 ³
A battery that has a size that satisfies the above relationship. A battery case having a through-hole communicating with the inside and outside of itself;
An electrode body housed in the battery case;
A sealing member comprising a rubber-like elastic body, and having a rubber plug portion that is press-fitted into the through hole from the outside of the battery case and tightly plugs the through hole;
The internal pressure of the battery case before the initial charge is the initial internal pressure Pb reduced from the atmospheric pressure Pa, and the through hole is sealed with the rubber plug portion, and then the initial charge is performed.
The through hole has a cylindrical portion whose inner peripheral surface forms a cylindrical shape,
The rubber plug portion has a tapered portion forming a tapered side surface having a circular cross section perpendicular to the axial direction of the through hole and having a larger diameter toward the outer side in the axial direction,
The tapered portion is compressed to the highest compression rate at the outer cylindrical edge which is the outer opening edge of the cylindrical portion,
The inner diameter of the cylindrical portion of the through hole is d,
Of the taper portion of the rubber plug portion, the outer diameter before compression of the maximum compression portion compressed to the maximum at the outer cylindrical edge is D,
The rubber plug has a hardness of H,
With the internal pressure of the battery case set to atmospheric pressure Pa, when the rubber plug portion is pulled out under atmospheric pressure Pa, a range that can be taken by the pulling strength Fa generated in the rubber plug portion is a first strength range AFa,
When the internal pressure of the battery case is set to the initial internal pressure Pb, the rubber plug portion is sealed when the rubber plug portion is pulled out under an atmospheric pressure Pa after the through hole is sealed with the rubber plug portion and before the initial charging. When the range that can be taken by the pulling strength Fb that occurs in the second strength range AFb,
A battery in which the inner diameter d of the cylindrical portion, the outer diameter D of the maximum compression portion, and the hardness H of the rubber plug portion are such that the first proof stress range AFa and the second proof stress range AFb are separated from each other. A manufacturing method of
In a state where the internal pressure of the battery case is reduced to the initial internal pressure Pb, the rubber plug portion of the sealing member is press-fitted into the through-hole from the outside to seal the through-hole, and the battery case is hermetically sealed A sealing step for sealing;
When the threshold value Fs is a value between the first proof stress range AFa and the second proof stress range AFb,
After the sealing step, a pulling test step of applying a pulling force Fh up to the threshold value Fs up to the threshold value Fs under atmospheric pressure Pa to try to pull out the rubber plug portion;
A battery manufacturing method comprising: an initial charging step of performing the initial charging for a battery in which the rubber plug portion is not pulled out in the pull-out test step. A battery manufacturing method according to claim 5,
The average value of the pullout proof strength Fa is Fav, the standard deviation is σa, and the first proof load range AFa is
Fav−4σa ≦ Fa ≦ Fav + 4σa,
The average value of the pullout proof strength Fb is Fbv, the standard deviation is σb, and the second proof stress range AFb is
When Fbv-4σb ≦ Fb ≦ Fbv + 4σb,
The inner diameter d of the cylindrical portion, the outer diameter D of the maximum compression portion, and the hardness H of the rubber plug portion,
Fav + 4σa <Fbv-4σb
As a size that satisfies the relationship
The threshold value Fs is
Fav + 4σa <Fs <Fbv-4σb
A battery manufacturing method having a value satisfying the above relationship. It is a manufacturing method of the battery of Claim 6, Comprising:
The inner diameter d of the cylindrical portion, the outer diameter D of the maximum compression portion, and the hardness H of the rubber plug portion,
The average value Fav of the pullout strength Fa and the average value Fbv of the pullout strength Fb are:
Fbv> 2Fav
A battery manufacturing method having a size satisfying the above relationship. A battery manufacturing method according to claim 7,
The inner diameter d (mm) of the cylindrical portion, the outer diameter D (mm) of the maximum compression portion, and the hardness H (° of the rubber plug portion, where the hardness H is a hardness meter according to the new JIS standard K6235. Is a value measured using a type A durometer) with respect to the initial internal pressure Pb (kPa).
| Pb | · π · d · D ² / (D ² −d ² )> 3.7 × 10 ² × H−8.1 × 10 ³
A battery manufacturing method having a size satisfying the above relationship.

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