JP2016076297A - Power storage element and method for manufacturing power storage element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase adhesion of a seal member to the circumference of a liquid injection hole.SOLUTION: A power storage element includes an electrode body 20 and a housing body 30 having a liquid injection hole 45, through which an electrolyte is injected, at a part of an outer wall, and housing the electrode body 20 therein. The circumference of the liquid injection hole 45 in an outer wall surface of the housing body 30 is a smooth surface having a lower surface roughness than sites other than the circumference.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a technique for improving the adhesion of a seal member to the periphery of a liquid injection hole.

  In a storage element such as a lithium ion secondary battery, a step of housing an electrode body in a battery case, a step of assembling a lid member on the battery case, and injecting an electrolyte into the battery case from a liquid injection hole formed in the lid member It is manufactured by a process. In general, the injection of the electrolytic solution is performed in a state in which the inside of the battery case is decompressed using the liquid injection hole in order to improve the injection property of the electrolytic solution. In Patent Document 1 below, a seal member (nozzle head) made of an elastic material is provided at the tip of a nozzle used for pressure reduction, and this is brought into close contact with the periphery of the liquid injection hole, so that the battery case is being decompressed and electrolyzed. During the liquid injection, the structure around the liquid injection hole is hermetically sealed.

JP 2013-191450 A

  When the airtightness around the liquid injection hole is lowered, a decompression failure occurs, so it is necessary to maintain the airtightness, and it has been demanded to improve the adhesion of the seal member around the liquid injection hole. In addition, the liquid injection hole may be used for a purpose of filling an inspection gas for inspecting the airtightness of the battery case. Since the airtight inspection is performed in a state where the liquid injection hole is closed with a sealing member such as a rubber plug, it is necessary to improve the adhesion of the seal member to the periphery of the liquid injection hole so as not to cause gas leakage.

  This invention is completed based on the above situations, Comprising: It aims at improving the adhesiveness of the sealing member with respect to a liquid injection hole periphery.

  An electricity storage device disclosed in the present specification includes an electrode body, a container having a liquid injection hole for injecting an electrolytic solution into a part of the outer wall, and a container for housing the electrode body, and the outer wall surface of the container Among these, the periphery of the liquid injection hole is a smooth surface having a small surface roughness as compared with other portions.

  According to the electricity storage device disclosed in the present specification, since the periphery of the liquid injection hole is a smooth surface, the adhesion of the seal member can be improved.

The perspective view of the battery which concerns on one Embodiment Battery exploded perspective view Cross section of electrode body Disassembled perspective view of lid member, positive electrode terminal portion, negative electrode terminal portion, positive electrode current collector, negative electrode current collector Battery vertical section Top view of the lid member Chart showing the surface roughness of the lid member The perspective view which looked at the cover member from the lower surface side Diagram showing the processing steps of the recess The figure which shows the manufacturing process of a battery (perspective view of an electrode assembly) The figure which shows the manufacturing process of a battery (The insertion process of an electrode assembly is shown) Diagram showing battery manufacturing process (shows airtightness inspection process) The figure which expanded D section of Drawing 12 (sectional view around a rubber stopper) Diagram showing the electrolyte injection process (showing the airtightness inspection process)

(Outline of this embodiment)
First, an outline of the electricity storage device of this embodiment will be described. The power storage element includes an electrode body and a container having a liquid injection hole for injecting an electrolytic solution into a part of the outer wall, and containing the electrode body, and the liquid injection is performed on the outer wall surface of the container. The periphery of the hole is a smooth surface having a small surface roughness compared to other parts. In this configuration, since the seal member is in close contact with the periphery of the liquid injection hole, when the pressure is reduced using the liquid injection hole or when the case is subjected to an airtight inspection, the area around the liquid injection hole can be kept airtight. I can do it.

  In this electrical storage element, the said container has a recessed part in the back surface side corresponding to the smooth surface formed in the circumference | surroundings of the said liquid injection hole. In this configuration, since the flat surface of the mold is transferred to the surface side of the container as the recess is formed, the periphery of the liquid injection hole can be processed into a smooth surface.

  In this power storage element, the smooth surface is formed by coining the periphery of the liquid injection hole. Coining processing is performed by a mold, so that the labor of processing can be reduced as compared with the case of processing a smooth surface by polishing or ultrasonic vibration.

<One Embodiment>
Hereinafter, a battery 10 that is an embodiment of a power storage device will be described with reference to the drawings.
1. Overall Structure of Battery 10 The battery 10 is a non-aqueous electrolyte secondary battery, more specifically, a lithium ion secondary battery. As shown in FIGS. 1 and 2, the battery 10 includes an electrode body 20, a case 30, a positive electrode current collector 60P, a negative electrode current collector 60N, a positive electrode terminal part 70P, and a negative electrode terminal part 70N. ing. In the following description, the arrangement direction of the positive electrode terminal portion 70P and the negative electrode terminal portion 70N is the X direction, the height direction of the case 30 is the Y direction, and the depth direction is the Z direction.

  The electrode body 20 includes a positive electrode sheet 23P, a negative electrode sheet 23N, and a separator 25. The positive electrode sheet 23P has a positive electrode active material supported on the surface of an aluminum foil. A positive electrode current collector foil 24P from which an aluminum foil or a copper foil is exposed is formed at one end of the positive electrode sheet 23P. The negative electrode sheet 23N has a negative electrode active material supported on the surface of a copper foil. A negative electrode current collector foil 24N from which the copper foil is exposed is formed at the other end of the negative electrode sheet 23N.

  As shown in FIG. 3, the electrode body 20 is obtained by winding the positive electrode sheet 23P and the negative electrode sheet 23N in a long cylindrical shape while shifting the positions in the left and right directions with the separator 25 interposed therebetween. is there. The electrode body 20 is housed in the case 30 in a state where the electrode body 20 is entirely covered with the insulating cover 27.

  As shown in FIG. 1, the case 30 includes a case main body 31 and a lid member 41. The case main body 31 is a metal member such as an aluminum alloy or steel. The case body 31 is a bottomed rectangular tube having a long side in the X direction and a short side in the Z direction, and includes four outer peripheral walls 32 </ b> A to 32 </ b> D and a bottom wall 35. The case body 31 accommodates the electrode body 20.

  The lid member 41 is a metal member such as an aluminum alloy or steel, and is a rectangular plate material that is long in the X direction. The lid member 41 corresponds to the size of the opening of the case body 31 and is attached to the opening of the case body 31 to seal the opening of the case body 31. The lid member 41, together with the case main body 31, constitutes the outer wall of the case 30 that is a container for housing the electrode body 20, and corresponds to the “outer wall” of the present invention.

  A first recess 43 and a second recess 44 are formed side by side in the X direction on the front surface (case outer surface) V of the lid member 41 on both sides in the X direction. The first concave portion 43 and the second concave portion 44 are both rectangular, and have a structure in which a gasket 75 and a bottom portion of the bolt case 85 described later are fitted. Also, rivet insertion holes 42 are formed on both sides in the X direction of the lid member 41. The rivet insertion hole 42 is located at the center of the first recess 43 and has a structure in which the rivet 71 having the head 72 accommodated in the gasket 75 passes therethrough.

  In addition, a liquid injection hole 45 and a pressure release valve 49 are formed side by side at the center of the lid member 41. The liquid injection hole 45 is provided for injecting the electrolytic solution into the case 30 and is sealed by the liquid stopper 50 after the electrolytic solution is injected. The liquid stopper 50 is made of metal and has a shaft portion 53 that penetrates the liquid injection hole 45 and a head portion 51 that closes the liquid injection hole 45.

  As shown in FIGS. 2 and 4, the positive electrode current collector 60 </ b> P and the negative electrode current collector 60 </ b> N are separately arranged on both sides in the X direction on the lower surface of the lid member 41. The positive electrode current collector 60P and the negative electrode current collector 60N are conductive metal members, a first connection portion 61 having a flat plate shape, and a second connection portion bent downward from a side end portion of the first connection portion 61. 65. The positive electrode current collector 60P and the negative electrode current collector 60N are fixed to the lid member 41 with the first connection portion 61 facing the lower surface of the lid member 41 and the second connection portion 65 facing downward. . Specifically, the first shaft portion 73 of the rivets 71P and 71N passes through the through hole 62 of the first connection portion 61, and the positive electrode current collector 60P is obtained by caulking the first shaft portion 73. The negative electrode current collector 60N is fixed to the lower surface of the lid member 41 with the resin plate 77 interposed therebetween.

  In addition, a pair of opposing walls 67 are formed in the second connection portion 65 of the positive electrode current collector 60P and the negative electrode current collector 60N. The second connection portion 65 of the positive electrode current collector 60P and the negative electrode current collector 60N faces the X direction with the electrode body 20 interposed therebetween. And a pair of opposing wall 67 provided in the positive electrode collector 60P is fixed to the positive electrode current collector foil 24P provided in the side edge part of the positive electrode sheet 23P by being pinched | interposed from the outer side by the clamping plate which is not shown in figure. Yes. On the other hand, the pair of opposing walls 67 provided on the negative electrode current collector 60N are fixed to the negative electrode current collector foil 24N provided on the side end portion of the negative electrode sheet 23N by being sandwiched from outside by a sandwiching plate (not shown). Yes.

  As shown in FIGS. 1 and 4, the positive electrode terminal portion 70 </ b> P and the negative electrode terminal portion 70 </ b> N are arranged separately on both sides in the X direction on the upper surface of the lid member 41. In this example, the positive terminal portion 70P is disposed on the right side of FIG. 1, and the negative terminal portion 70N is disposed on the left side of FIG. The structures of the terminal portions 70P and 70N are common on the positive electrode side and the negative electrode side. Hereinafter, the structure of the terminal portion will be described by taking the positive electrode terminal portion 70P as an example.

  As shown in FIG. 4, the positive terminal portion 70P includes a metal rivet 71P, a gasket 75, a resin plate 77, a metal terminal bolt 81P, a bolt case 85, and a metal terminal plate 91P. Prepare.

  The rivet 71P is a double-shaft type, and a first shaft portion 73 and a second shaft portion 74 are provided on both upper and lower sides of the head 72. The first shaft portion 73 of the rivet 71P passes through the through hole of the gasket 75, the rivet insertion hole 42 of the lid member 41, the through hole 78 of the resin plate 77, and the through hole 62 of the positive electrode current collector 60P in this order. The rivet 71P fixes the positive electrode current collector 60P to the lid member 41 by caulking the tip of the first shaft portion 73 that penetrates the gasket 75, the lid member 41, the resin plate 77, and the positive electrode current collector 60P.

  The gasket 75 is an insulating synthetic resin material, and has a box shape that can accommodate the head 72 of the rivet 71P. A through hole through which the first shaft portion 73 of the rivet 71P passes and an annular protrusion 76 are formed along the periphery of the bottom surface of the gasket 75.

  The gasket 75 is disposed on the upper surface side of the lid member 41 while fitting the annular protrusion 76 into the rivet insertion hole 42, and insulates the lid member 41 from the rivet 71P. Further, the gasket 75 is filled with a sealing material to seal the periphery of the rivet insertion hole 42 and the periphery of the rivet 71P.

  The resin plate 77 is a synthetic resin member having insulating properties. The resin plate 77 is a rectangle that is long in the X direction, and a through hole 78 is formed corresponding to the rivet insertion hole 42 of the lid member 41. In addition, on the lower surface of the resin plate 77, a receiving portion 77A capable of receiving the first connection portion 61 of the positive electrode current collector 60P is formed. The resin plate 77 is disposed on the lower surface side of the lid member 41 and insulates the lid member 41 and the positive electrode current collector 60P.

  The terminal bolt 81P is for attaching a terminal (not shown) provided on a harness connected to an electric device and a bus bar (not shown) for electrically connecting batteries, and the head 82 is accommodated in the bolt case 85. However, the lid member 41 is arranged side by side with the rivet 71P on the upper surface side.

  The bolt case 85 is a synthetic resin material having insulating properties, like the resin plate 77 and the gasket 75. The bolt case 85 has a box shape and accommodates the head 82 of the terminal bolt 81P. The bolt case 85 is arranged alongside the gasket 75 on the upper surface side of the lid member 41, and is bonded and fixed to the lid member 41. The bolt case 85 is formed with a rotation restricting portion (not shown) and prevents the terminal bolt 81P from rotating.

  The terminal plate 91P is a metal flat plate that is long in the X direction, and has a first through hole 92 and a second through hole 93 formed therein. The terminal plate 91P is disposed on the upper surface side of the lid member 41. The second shaft portion 74 of the rivet 71P passes through the first through hole 92, and the terminal bolt 81P passes through the second through hole 93. ing. The terminal plate 91P is fixed to the lid member 41 via the rivet 71P by crimping the tip of the rivet 71P protruding from the first through hole 92.

  As described above, the terminal bolt 81P on the positive electrode side is connected to the positive electrode sheet 23P via the terminal plate 91P, the rivet 71P, and the positive electrode current collector 60P, and the terminal bolt 81N on the negative electrode side is connected to the terminal plate 91N, the rivet 71N, and the negative electrode collector. It has a structure connected to the negative electrode sheet 23N through the electric body 60N.

2. FIG. 7 shows two parts on the surface V side of the lid member 41, that is, the periphery of the liquid injection hole 45 (the area inside the arc C in FIG. 6) and the other parts ( This is data obtained by measuring the surface roughness (specifically, “Ra”, “Rz”, “RSm”) with respect to a range outside the arc C).

  As shown in FIG. 7A, the average value of “Ra” is 0.118 [μm] and the average value of “Rz” around the liquid injection hole 45 (range inside the arc C in FIG. 6). Is 1.002 [μm], and the average value of “RSm” is 0.057 [mm]. Note that the measurement is performed at three locations inside the arc C, and each value is an average value of the three locations.

  On the other hand, as shown in FIG. 7B, the average value of “Ra” is 0.349 [μm] and the average value of “Rz” is 2.4 in the other parts (range outside the arc C). The average value of 240 [μm] and “RSm” is 0.062 [mm]. In addition, the measurement is performed at three locations outside the arc C, and each value is an average value of these three locations.

  As described above, the surface V of the lid member 41 has a smaller average value of “Ra”, “Rz”, and “RSm” around the liquid injection hole 45, and the surface roughness is higher than that of other portions. The smooth surface is small. By making the periphery of the injection hole 45 a smooth surface, seal members such as the packing 250 and the rubber plug 150 are closely attached to the periphery of the injection hole 45 without any gaps. When inspecting, the periphery of the liquid injection hole 45 can be kept airtight. “Ra” is the arithmetic average roughness, “Rz” is the maximum height roughness, and “RSm” is the average length of the roughness curve elements (see JIS B 0601: 2013).

  Further, as shown in FIG. 8, a concave portion 47 is provided on the back surface (surface inside the case) W side of the lid member 41 corresponding to the liquid injection hole 45. The smooth surface on the front surface V side and the concave portion 47 on the rear surface W side of the lid member 41 are formed by coining the periphery of the liquid injection hole 45. The coining process is a process of transferring the shape and pattern of the mold to the metal material by compressing the metal material sandwiched from both sides by the mold. More specifically, as shown in FIG. 9, the mold includes a die 120 having a flat upper surface 125, a punch P that moves up and down with the die 120, and a drive device that moves the punch P in the vertical direction (see FIG. 9). Abbreviation). The lid member 41 is placed on the upper surface 125 of the die 120 with the liquid injection hole 45 coinciding with the center of the punch P and the surface V facing downward, and the back surface W of the lid member 41 faces the punch P. It has become.

  As shown in FIG. 9, the upper surface 125 of the die 120 is larger than the outer shape of the lid member 41, whereas the punch P is smaller than the outer shape of the lid member 41, and the die 120 with respect to the surface V of the lid member 41. The contact area G <b> 1 is larger than the contact area G <b> 2 of the punch P with respect to the back surface W of the lid member 41. In other words, the contact area G2 on the punch P side is smaller than the contact area G1 on the die 120 side. The die 120 corresponds to the “first mold” of the present invention, and the punch P corresponds to the “second mold” of the present invention.

  Therefore, as shown in FIG. 9, when the punch P is lowered and the lid member 41 placed on the upper surface 125 of the die 120 is pressed, the liquid injection hole 45 that contacts the punch P in the back surface W of the lid member 41. Since the periphery of the punch P is strongly pressed and crushed by the punch P, the shape of the punch P is transferred to the same portion, and the recess 47 is formed. Simultaneously with the formation of the recess 47, the flat surface 125 of the die 120 is transferred to the surface V of the lid member 41. From the above, the periphery of the liquid injection hole 45 (the range inside the arc C in FIG. 6) of the surface V of the lid member 41 can be made smooth. Note that the position and size of the smooth surface substantially coincide with the position and size of the recess 47.

  In addition, since the flat surface 125 of the mold 120 is not transferred in the range other than the periphery of the liquid injection hole 45 in the surface V of the lid member 41, the surface roughness at the time of manufacturing the metal plate (the surface roughness of the roll for rolling). ) Remains as it is and becomes rougher than the periphery of the liquid injection hole 45 as described above.

3. Manufacturing Process of Battery 10 The battery 10 is manufactured by the following processes (A) to (F).
(A) The process of smoothing the periphery of the liquid injection hole in the surface of the lid member (B) The assembly process of the electrode assembly (C) The insertion process of the electrode assembly (D) The welding process (E) The airtight inspection process (F ) Electrolytic solution injection process

  In the step (A), the periphery of the liquid injection hole 45 in the lid member 41 is coined to smooth the periphery of the liquid injection hole 45 (that is, process into a smooth surface). The coining process is a process of transferring the shape and pattern of a mold to a metal material. In this example, the coining process is performed using a punch P and a die 120 as shown in FIG. More specifically, first, as shown in FIG. 9A, the lid member 41 is placed on the upper surface 125 of the die 120 with the liquid injection hole 45 aligned with the center of the punch P and the surface V facing downward. Set to.

  Thereafter, as shown in FIG. 9, the punch P is lowered and the lid member 41 placed on the upper surface 125 of the die 120 is pressed. As a result, the periphery of the liquid injection hole 45 in contact with the punch P in the back surface W of the lid member 41 is strongly pressed and crushed by the punch P, so that the shape of the punch P is transferred to the same portion, and the recess 47 is formed. It is formed. Simultaneously with the formation of the recess 47, the flat surface 125 of the die 120 is transferred to the surface V of the lid member 41. From the above, the periphery of the liquid injection hole 45 in the surface V of the lid member 41 is processed into a smooth surface.

  Note that the step (A) can be both performed as a separate step after the lid member 41 is processed and incorporated into a part of the step for processing the lid member 41.

  In the assembly process of the electrode assembly 100 in (B), first, each component such as the positive electrode current collector 60P, the negative electrode current collector 60N, the positive electrode terminal portion 70P, and the negative electrode terminal portion 70N is assembled to the lid member 41. Integrate. Thereafter, the positive electrode current collector foil 24P and the negative electrode current collector foil 24N of the electrode body 20 are respectively fixed to the positive electrode current collector 60P and the negative electrode current collector 60N fixed to both sides of the lower surface of the lid member 41. Thereby, as shown in FIG. 10, the electrode assembly 100 in which the lid member 41 is fixed to the electrode assembly 20 is assembled.

  In the insertion process of the electrode assembly 100 in (C), as shown in FIG. 11, the electrode assembly 100 assembled in the process (B) is inserted into the case main body 31 together with the insulating cover 27 using an insertion machine or the like. Insert. After the insertion, the lid member 41 overlaps the upper surface of the case body 31 and closes the opening of the case body 31.

  (D) In the welding process, laser is irradiated from the laser welder along the outer periphery of the lid member 41, and the lid member 41 is laser welded to the case body 31 on the entire circumference.

  (E) In the airtight inspection process, the airtight state of the case 30 is inspected. Specifically, as shown in (1) of FIG. 12, first, the inspection gas (specifically helium gas) is filled into the case 30 from the liquid injection hole 45. Then, after filling with the inspection gas, the rubber stopper 150 is assembled in the liquid injection hole 45 of the lid member 41 as shown in FIG. The rubber plug 150 has a substantially cylindrical shape. The lower surface 151 of the rubber plug 151 is a flat plane, and the outer peripheral portion is rounded. The rubber plug 150 is assembled so that the lower surface 151 comes into contact with the periphery of the liquid injection hole 45.

  After assembling the rubber plug 150 so as to contact the periphery of the liquid injection hole 45, as shown by the arrow in FIG. 13, the rubber plug 150 is pressed toward the liquid injection hole 45 using a jig; To do. Thereby, the lower surface 151 of the rubber plug 150 is elastically adhered around the liquid injection hole 45 with a predetermined contact pressure.

  And as demonstrated previously, the circumference | surroundings of the liquid injection hole 45 are smooth surfaces among the surfaces V of the cover member 41. FIG. Therefore, as shown in FIG. 13, the lower surface 151 of the rubber plug 150 is closely attached around the liquid injection hole 45 without a gap. Therefore, the periphery of the liquid injection hole 45 can be kept airtight. The rubber plug 150 corresponds to the “sealing member” of the present invention.

  Thereafter, as shown in (3) of FIG. 12, the inspection gas leaking from the case 30 is detected using the inspection probe 170. If the inspection gas exceeding the reference value is detected, the case 30 is determined to be airtight. If the inspection gas exceeding the reference value is not detected, the case 30 is determined to be normal, that is, the airtightness is maintained. If there is no hermetic failure as a result of the inspection, the process proceeds to the next electrolyte injection step.

  (F) In the electrolyte solution injection step, the electrolyte solution is injected into the case body 31 using the injector 200. Specifically, the injector 200 includes an injection head 210 having a packing 250 at the tip of the tube 230 as shown in FIG. The packing 250 is made of rubber, and the lower end surface 251 is a contact surface with the surface V of the lid member 41. A pressure reducer 280 and a tank 290 containing an electrolytic solution are connected to the injection head 210 via a three-way valve 270. By switching the three-way valve 270, the pressure reducer 280 is connected to the injection head 210. And the tank 290 can be selectively connected. The packing 250 corresponds to the “sealing member” of the present invention.

  As shown in FIG. 14, the injection head 210 of the injection machine 200 is mounted so as to press the packing 250 against the surface V of the lid member 41 while aligning the tube 230 with the liquid injection hole 45. As described above, since the periphery of the liquid injection hole 45 of the lid member 41 is a smooth surface, the lower end surface 251 of the packing 250 is elastic with no gap around the liquid injection hole 45 when the injection head 210 is attached. The periphery of the liquid injection hole 45 is kept airtight.

  Then, after the injection head 210 is mounted, the switching valve 270 is switched to the decompressor 280 side. Thereafter, by driving the decompressor 280, the air in the case 30 is exhausted through the tube 230, and the case 30 is decompressed.

  When the case 30 is depressurized to a predetermined level, the switching valve 270 is switched to the tank 290 side. Thereby, the electrolytic solution is filled from the tank 290 into the decompressed case 30. When a predetermined amount of electrolyte is injected into the case 30, the switching valve 270 is closed. This completes the electrolyte injection step. Thereafter, the liquid stopper 50 is assembled into the liquid injection hole 45 of the lid member 41 and laser welding is performed. Thereby, the liquid injection hole 45 is sealed, and the battery 10 is completed.

4). Explanation of Effect The lid member 41 of the battery 10 has a smooth surface around the liquid injection hole 45. Therefore, the rubber plug 150 used in the airtightness inspection process and the packing 250 used in the electrolyte injection process are in close contact with the periphery of the liquid injection hole 45 without a gap. Accordingly, during the airtight inspection, no leakage of the inspection gas occurs around the liquid injection hole 45, and the airtight inspection of the case 30 can be performed with high accuracy. Further, when the case 30 is depressurized in the electrolytic solution injection step, the periphery of the injection hole is kept in an airtight state, so that the depressurization failure of the case 30 does not occur, and the electrolytic solution is injected for a predetermined time. I can do it.

  Further, the lid member 41 is processed to have a smooth surface around the liquid injection hole 45 by coining the recess 47. Coining processing is performed with a mold, so that the labor of processing can be reduced as compared with the case of processing a smooth surface by polishing or ultrasonic vibration.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  (1) In the above embodiment, a lithium ion secondary battery is illustrated as an example of a power storage element, but the present invention is applicable to any power storage element having a bottomed case body that houses an electrode body, The present invention can also be applied to batteries other than lithium ion secondary batteries and capacitors such as electric double layer capacitors.

  (2) In the above embodiment, the example in which the liquid injection hole 45 is formed in the lid member 41 has been described. However, the liquid injection hole 45 may be provided on the case body 31 side.

  (3) In the above embodiment, the example in which the periphery of the liquid injection hole 45 is processed into a smooth surface by coining the concave portion 47 on the back surface W of the lid member 41 has been shown. Other than the coining process such as polishing or ultrasonic vibration.

  (4) In the above-described embodiment, the rubber plug 150 having a shape in surface contact with the periphery of the liquid injection hole 45 is used, but the present invention is not limited to this. For example, the rubber plug 150 may have a shape that makes line contact so as to cover the periphery of the liquid injection hole 45. Specifically, a protrusion protruding in a cylindrical shape from the lower surface 150 of the rubber stopper 150 toward the periphery of the liquid injection hole 45 may be formed, and the protrusion may be in line contact with the periphery of the liquid injection hole 45. .

DESCRIPTION OF SYMBOLS 10 ... Battery 20 ... Electrode body 30 ... Case (equivalent to the "container" of this invention)
31 ... Case body 41 ... Cover member (corresponding to "outer wall" of the present invention)
45 ... Injection hole 50 ... Liquid stopper 120 ... Die (corresponding to "first mold" of the present invention)
150 ... rubber plug (corresponding to "seal member" of the present invention)
250 ... packing (corresponding to "sealing member" of the present invention)
P ... Punch (corresponding to "second mold" of the present invention)
V ... Front side W ... Back side

Claims (8)

An electrode body;
It has a liquid injection hole for injecting an electrolyte into a part of the outer wall, and a container for housing the electrode body,
The electrical storage element in which the periphery of the liquid injection hole is a smooth surface having a small surface roughness compared to other portions of the outer wall surface of the container. The power storage device according to claim 1,
The container is a power storage element having a recess on the back surface side corresponding to a smooth surface formed around the liquid injection hole. The electric storage device according to claim 1 or 2,
The smooth surface is a power storage element formed by coining the periphery of the liquid injection hole. A method of manufacturing a storage element,
A method for manufacturing an electric storage element, comprising a step of performing coining on a periphery of a liquid injection hole formed in a part of an outer wall of a container that houses an electrode body. It is a manufacturing method of the electrical storage element according to claim 4,
The step of performing the coining process includes a first mold that faces the outer wall surface of the container and a second mold that faces the outer wall rear surface of the container, and surrounds the liquid injection hole in the outer wall of the container. Is a process of sandwiching and compressing from both sides,
The method for manufacturing a power storage element, wherein a contact area of the first mold with the outer wall surface is larger than a contact area of the second mold with the outer wall back surface. A method of manufacturing a storage element,
A method for manufacturing a power storage element, comprising a step of smoothing a periphery of a liquid injection hole formed in a part of an outer wall of a container that houses an electrode body. A method of manufacturing a storage element,
A step of depressurizing the container using the liquid injection hole in a state where a seal member is in close contact with a smooth surface around the liquid injection hole formed on a part of the outer wall of the container containing the electrode body The manufacturing method of the electrical storage element which has this. A method of manufacturing a storage element,
Manufacture of a storage element having a step of performing an airtight inspection of the container in a state where a seal member is in close contact with a smooth surface around a liquid injection hole formed on a part of an outer wall of the container containing the electrode body Method.

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