JP5724696B2 - Battery manufacturing method - Google Patents

Description

  The present invention provides a battery case having a through-hole communicating with the inside and the outside of the battery case, an electrode body and an electrolytic solution accommodated in the battery case, and a sealing formed by hermetically sealing the through-hole of the battery case from the outside. The present invention relates to a method for manufacturing a battery including a member.

Conventionally, a battery case having a through hole such as a liquid injection hole for injecting an electrolytic solution, an electrode body and an electrolyte contained in the battery case, and the through hole of the battery case are hermetically sealed from the outside. A battery including a sealing member is known. As the sealing member, for example, there is a member in which a rubber plug portion made of a rubber-like elastic body is joined to a metal lid portion made of metal. Among these, the rubber plug portion is press-fitted into the through hole of the battery case from the outside, and the through hole is hermetically sealed. On the other hand, the metal lid part is joined to the battery case while covering the rubber plug part from the outside of the battery case and pressing the rubber plug part toward the inside of the battery case. By doing in this way, the airtight sealing of the through-hole by a rubber plug part can be made more reliable.
In addition, the battery disclosed by patent document 1 is mentioned as a battery of the form which sealed the through-hole with the sealing member which has a rubber plug part and a metal cover part, for example.

JP 2009-87659 A

  In the conventional battery, as described above, it was considered that the hermetic sealing of the through hole should be performed by the rubber plug portion. Therefore, strictly speaking, the airtightness between the metal lid portion and the battery case is strictly required. There wasn't. However, since the rubber plug portion deteriorates with time, the airtightness between the rubber plug portion and the through hole also decreases with time. In particular, in-vehicle batteries such as hybrid vehicles and electric vehicles are used for a long period of time, for example, 10 years or more, and there is a concern that the airtightness may decrease due to the deterioration with time.

  When the rubber plug part deteriorates and the airtightness between the rubber plug part and the through hole decreases, the electrolyte contained in the battery case enters between the rubber plug part and the through hole, and further, metal When the airtightness between the lid and the battery case is low, the electrolyte may leak to the outside of the battery through the metal lid and the battery case. As a result, the electrolyte in the battery case is insufficient, and the battery characteristics may deteriorate. Conversely, moisture in the atmosphere may enter the battery case between the metal lid part and the battery case and between the rubber plug part and the through hole, and the battery characteristics may deteriorate.

In order to solve this problem, even if the rubber plug portion is deteriorated and the airtightness between the rubber plug portion and the through hole is lowered, the metal lid portion is not connected to the outside of the battery case. It is conceivable to securely and airtightly connect the battery case.
However, in such a battery, the rubber plug portion has not yet deteriorated immediately after manufacture, and the gap between the rubber plug portion and the through hole is hermetically sealed. That is, this battery is double-sealed by the close contact between the rubber plug portion and the through hole and the joining of the metal lid portion and the battery case. For this reason, even if a sealing failure occurs due to a defect in the joining between the metal lid and the battery case, it is difficult to determine the battery in which this sealing failure has occurred by inspection. Therefore, it is difficult to manufacture a battery in which the metal lid portion is securely and airtightly joined to the battery case.

  The present invention has been made in view of such a situation, and in a battery in which a covering portion of a sealing member and a battery case are joined in an airtight manner and a through hole of the battery case is sealed in an airtight manner. It is an object of the present invention to provide a battery manufacturing method in which the airtightness between the covering portion of the stop member and the battery case is easily and reliably inspected.

  One aspect of the present invention for solving the above problems is a battery case having a through-hole communicating with the inside and outside of the battery, an electrode body housed in the battery case, and an electrolyte solution housed in the battery case. And a sealing member that hermetically seals the through hole from the outside of the battery case, which is made of a rubber-like elastic body, and the insertion portion that is inserted into the through hole, and the insertion portion is A sealing member having a covering portion formed by airtightly and annularly joining a peripheral portion of an annular hole surrounding the periphery of the through hole in the battery case while covering from the outside, A temporary sealing step in which the insertion portion is press-fitted from the outside into the through hole of the battery case in which the electrolytic solution is accommodated, and the through hole is temporarily sealed in the insertion portion in an airtight manner; After the stopping step, while covering the insertion portion from the outside, A main sealing step for airtightly and annularly joining the covering portion to the hole peripheral portion of the battery case, and after the main sealing step, the covering portion of the sealing member and the hole peripheral portion of the battery case An airtight inspection process for inspecting the airtightness between the temporary sealing process and the main sealing process, and the through hole is temporarily sealed in the insertion part by the elasticity of the insertion part. Temporary sealing of the through hole by the insertion portion is performed at an ambient temperature within a possible first temperature range, and the airtightness inspection step is performed at a temperature lower than the first temperature range and due to a decrease in elasticity of the insertion portion. This is a method for manufacturing a battery, which is performed at an environmental temperature within a second temperature range in which stopping cannot be maintained.

  In this battery manufacturing method, the process from the temporary sealing step to the main sealing step is performed at an environmental temperature within a first temperature range in which the through hole can be temporarily sealed in the insertion portion by the elasticity of the insertion portion. For this reason, in a temporary sealing process, a through-hole can be reliably airtightly sealed by an insertion part. In addition, it is possible to prevent the electrolyte contained in the battery case from leaking to the outside of the battery case (such as around the hole) through the through hole after the temporary sealing and before the main sealing. Therefore, during the main sealing step, it is possible to prevent the electrolyte leaking from the through hole from entering between the covering portion of the sealing member and the peripheral portion of the hole of the battery case, resulting in a sealing failure. The part and the hole peripheral part can be reliably joined.

  On the other hand, the airtightness inspection process is performed at an environmental temperature within a second temperature range that is lower than the first temperature range and in which the temporary sealing of the through hole by the insertion portion cannot be maintained due to a decrease in elasticity of the insertion portion. For this reason, during this airtight inspection process, temporary sealing cannot be maintained, the airtightness between the insertion portion and the through hole is reduced, and the gas can flow between the insertion portion and the through hole. Become. Therefore, by inspecting whether the gas in the battery case does not leak out of the battery case, it is possible to easily and reliably inspect the airtightness between the covering portion and the hole peripheral portion of the battery case. . And the battery in which the sealing defect has arisen among these can be excluded reliably. Therefore, a battery capable of airtightly sealing the liquid injection hole with the sealing member (its covering portion) for a long period of time with high airtight reliability between the covering portion of the sealing member and the hole peripheral portion of the battery case is easy and easy. Can be manufactured reliably. Therefore, a battery in which the airtightness between the covering portion of the sealing member and the battery case is easily and reliably inspected can be manufactured.

  Furthermore, in the battery manufacturing method, the rubber-like elastic body includes a temperature range in which the first temperature range is 20 to 35 ° C and the second temperature range is -50 to 10 ° C. It is preferable that the battery is made of a material that overlaps at least part of the range.

  By forming the insertion portion with a rubber-like elastic body made of such a material, the temporary sealing process to the main sealing process may be performed at an ambient temperature within a temperature range of 20 to 35 ° C. The environmental temperature does not have to be extremely high or low. Therefore, these steps can be easily performed, and the manufacturing cost can be reduced. In addition, the airtight inspection process may be performed at an environmental temperature that falls within the second temperature range within a temperature range of −50 to 10 ° C. The environmental temperature of the airtight inspection process is not set to an extremely high or low temperature. You can do it. Therefore, the airtight inspection process can be easily performed, and the manufacturing cost can be reduced.

  Furthermore, in any of the above-described battery manufacturing methods, the temporary sealing step may be performed under reduced pressure, and the main sealing step may be a battery manufacturing method performed under atmospheric pressure.

  By performing the temporary sealing step under reduced pressure, the inside of the battery case after the temporary sealing can be brought into a reduced pressure state (negative pressure). For this reason, it is possible to prevent the internal pressure of the battery case from increasing rapidly even if gas is generated in the battery case during the conditioning process (initial charging process) performed after the main sealing process or in subsequent use. On the other hand, since the main sealing step for joining by welding or the like is performed under atmospheric pressure, the main sealing step can be easily performed as compared with the case where the main sealing step is performed under reduced pressure.

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. Regarding the method for manufacturing a lithium ion secondary battery according to Embodiment 1, in the temporary sealing step, the insertion member of the sealing member is press-fitted into the liquid injection hole, and the liquid injection hole is temporarily sealed airtight with the insertion member. It is explanatory drawing which shows. It is a graph which shows the relationship between environmental temperature and the leak amount of helium gas in the airtight test done about the test batteries 1 and 2. FIG. 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 with a sealing member 180 described later in a state where the inside of the battery case 110 is depressurized from the atmospheric pressure (negative pressure state). Further, the case lid member 113 includes a positive electrode terminal 150 and a negative electrode terminal 160 that are each configured to extend from the inside of the battery case 110 to the outside, and bolts 153 and 153 that are insulating members made of resin. 155 and 155 (see FIGS. 1 and 4).

  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 (see FIG. 2), and is connected to the positive electrode terminal 150 described above ( (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 to the other side SB in the axis AX direction in a spiral shape (see FIG. 2), and is connected to the negative electrode terminal 160 described above ( (See FIG. 1).
The separator 141 is a porous film made of resin and has a strip shape.

Next, the liquid injection hole 170 and the sealing member 180 will be described (see FIGS. 5 to 7).
The liquid injection hole 170 is formed to inject the electrolytic solution 117 into the battery case 110, and extends in the direction of the axis BX in a form penetrating between the inner main surface 113c and the outer main surface 113d of the case lid member 113. The battery case 110 communicates with the inside and outside. The liquid injection hole 170 is a stepped hole in which an inner cylindrical portion 171 forming a circular hole and an outer cylindrical portion 173 forming a circular hole having a diameter larger than the circular cylindrical hole are coaxially connected.

  The inner cylindrical portion 171 is formed of a cylindrical inner peripheral surface 171f having a cylindrical shape, and is positioned on the inner BC (inside the battery, downward in FIG. 5) in the axis BX direction, and opens to the inner main surface 113c. ing. The outer cylindrical portion 173 is configured by a cylindrical outer peripheral surface 173f having a cylindrical shape, and is positioned on the outer side BD in the axis BX direction (on the outside of the battery, upward in FIG. 5), and is open on the outer main surface 113d. doing. The cylindrical inner peripheral surface 171f forming the inner cylindrical portion 171 and the cylindrical inner peripheral surface 173f forming the outer cylindrical portion 173 are arranged via an annular intermediate surface 172f parallel to the inner main surface 113c and the outer main surface 113d. It is connected.

On the other hand, the sealing member 180 includes a covering member (covering portion) 181 and an insertion member (inserting 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. And a coating portion outer surface 181d which is a main surface located on the outer side CD in the direction of the axis CX (on the opposite side to the case lid member 113, upper side in FIGS. 5 and 7). It has a disk shape larger than the inner diameter of the portion 173).

  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 part 181m along the outer peripheral edge of the covering member 181 is welded to the annular hole peripheral part 113m surrounding the liquid injection hole 170 in the case lid member 113 over the entire periphery. An annular welded portion 181y is formed in plan view. Thereby, the space between the peripheral edge portion 181m of the covering member 181 and the hole peripheral portion 113m of the battery case 110 is hermetically sealed.

  The insertion member 183 is made of a rubber-like elastic body. Specifically, it consists of perfluoroelastomer (manufactured by DuPont, Kalrez). The rubbery elastic body has a glass transition point Tg of -5 to 5 ° C. This rubber-like elastic body has sufficiently high elasticity in a temperature range of 13 to 200 ° C. On the other hand, the elasticity is clearly reduced in a temperature range of 9 ° C. or lower, and the elasticity is almost lost at 0 ° C. or lower.

  The insertion member 183 has a truncated cone shape having a small-diameter top surface 183c, a large-diameter bottom surface 183d, and a side surface 183f connecting between them. The top surface 183 c is smaller in diameter than the inner diameter of the inner cylindrical portion 171 of the liquid injection hole 170. The bottom surface 183d is larger in diameter than the top surface 183c, larger in diameter than the inner cylindrical portion 171 of the liquid injection hole 170, and larger in diameter than the inner diameter of the outer cylindrical portion 173 in the liquid injection hole 170. It is small.

  The insertion member 183 is integrated with the covering member 181 by joining the bottom surface 183d thereof to the center of the covering portion inner side surface 181c of the covering member 181. The insertion member 183 extends from the inner surface 181c of the covering member 181 to the inner sides BC and CC (downward in FIG. 5) in the directions of the axes BX and CX, and is inserted into the liquid injection hole 170.

  More specifically, the rubber-like elastic body forming the insertion member 183 has a temperature range of 13 to 200 ° C. (corresponding to the first temperature range described above) including the temperature range of 20 to 35 ° C. as described above. , Have sufficiently high elasticity. Therefore, if temporary sealing and the subsequent steps are performed at an environmental temperature within this first temperature range (for example, 25 ° C.), the side surface 183f of the insertion member 183 is formed in the liquid injection hole 170 by the elasticity of the insertion member 183. Then, the liquid injection hole 170 is hermetically sealed (tightly plugged) with the insertion member 183 by being in airtight pressure contact with the corner portion 171fa formed by the cylindrical inner peripheral surface 171f and the intermediate surface 172f. For this reason, the liquid injection hole 170 continues to be double-sealed by the covering member 181 and the insertion member 183 of the sealing member 180 by keeping the ambient temperature within this range. In particular, since the first temperature range includes a temperature range of 20 to 35 ° C., the seal by the insertion member 183 can be maintained while easily maintaining the temperature within the range of 20 to 35 ° C.

  On the other hand, as described above, the rubber-like elastic body forming the insertion member 183 clearly decreases in elasticity at a temperature range of 9 ° C. or lower (corresponding to the second temperature range described above), and hardly has elasticity at 0 ° C. or lower. Disappear. Therefore, at the environmental temperature (for example, −5 ° C.) within the second temperature range, the side surface 183f of the insertion member 183 is in contact with the corner portion 171fa of the liquid injection hole 170, but the insertion part 183 and the liquid injection hole 170 are in contact. The temporary sealing between the two cannot be maintained, and the space between them is not hermetic but allows the gas to flow. For this reason, the liquid injection hole 170 is sealed only by the covering member 181 of the sealing member 180 under this temperature environment.

Next, a method for manufacturing the battery 100 will be described. First, a separately formed belt-like positive electrode plate 121 and a belt-like 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).
Separately, a sealing member 180 (see FIG. 7) composed of a covering member 181 and an insertion member 183 is formed. Specifically, the covering member 181 made of a metal plate is set in an injection molding die, and the insertion member 183 is covered by injection molding using perfluoroelastomer (manufactured by DuPont, Kalrez) as described above. Molded integrally with 181.

  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).

  Next, the airtightness between the welded case main body member 111 and the case lid member 113 is inspected. Specifically, the battery 100 is placed in a chamber, the chamber is filled with helium gas, and a suction nozzle is attached to the liquid injection hole 170 of the case lid member 113 in an airtight manner. The pressure is reduced. When there is a sealing failure between the case main body member 111 and the case lid member 113, the helium gas outside the battery case 110 enters the battery case 110. By detecting this invading helium gas, The airtightness between the case main body member 111 and the case lid member 113 is inspected.

  Next, in a temperature environment of 25 ° C., the battery is placed in a vacuum chamber to depressurize the vacuum chamber. 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 (including the hole peripheral portion 113m) is cleaned. Specifically, the periphery of the liquid injection hole 170 is wiped with a nonwoven fabric. When the electrolytic solution 117 is injected, the electrolytic solution 117 may adhere to the periphery of the liquid injection hole 170. This cleaning can clean the periphery of the liquid injection hole 170.

  Next, a temporary sealing step is performed under this reduced pressure and a temperature environment of 25 ° C. That is, the insertion member 183 is press-fitted into the liquid injection hole 170 from the outside of the battery case 110, and the liquid injection hole 170 is temporarily sealed airtight with the insertion member 183. More specifically, the insertion member 183 of the sealing member 180 is press-fitted into the liquid injection hole 170 from the outer side BD in the axis BX direction, and the side surface 183f of the insertion member 183 is inserted into the corner 171fa of the liquid injection hole 170. Press contact (see FIG. 8). Thereby, the liquid injection hole 170 is temporarily sealed (sealed) with the insertion member 183.

  In the first embodiment, the first temperature range in which the injection member 170 can be hermetically sealed by the elasticity of the insertion member 183 from the temporary sealing step to the main sealing step described later (this embodiment). In the first embodiment, it is performed at an environmental temperature within the range of 13 to 200 ° C. (25 ° C. in the first embodiment). For this reason, since the insertion member 183 has high elasticity during the period from the temporary sealing step to the main sealing step, the contact portion 183t of the insertion member 183 that is in contact with the corner portion 171fa of the liquid injection hole 170 is , It deforms due to its own elasticity, and comes into close contact with the corner 171fa of the liquid injection hole 170.

Subsequently, in a temperature environment of 25 ° C., 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 in the temporary sealing process, even if the battery 100 is returned to atmospheric pressure, the inside of the battery case 110 is kept in a reduced pressure state.
By the way, when the liquid injection hole 170 is not temporarily sealed, the electrolyte solution 117 accommodated in the battery case 110 may leak out of the battery or may adhere to the hole peripheral portion 113m of the battery case 110. is there. However, in the first embodiment, since the liquid injection hole 170 is temporarily sealed airtightly by the insertion member 183 in the temporary sealing step described above, the electrolyte 117 can be reliably prevented from leaking outside the battery. Further, the main sealing step described below can also be performed under atmospheric pressure while keeping the inside of the battery case 110 in a reduced pressure state.

  Next, the main sealing step is performed under this atmospheric pressure and a temperature environment of 25 ° C. That is, the peripheral edge portion 181m of the covering member 181 that covers the insertion member 183 from the outside of the battery case 110 is joined to the hole peripheral portion 113m of the battery case 110 (case cover member 113) in an airtight and annular manner. More specifically, 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, and the peripheral portion 181m of the covering member 181 is brought into contact with the hole peripheral portion 113m of the case lid member 113. Let In this state, laser welding is performed, and the peripheral portion 181m of the covering member 181 and the hole peripheral portion 113m of the battery case 110 are welded over the entire circumference to form an annular welded portion 181y. Thereby, the space between the peripheral edge portion 181m of the covering member 181 and the hole peripheral portion 113m of the battery case 110 is hermetically sealed.

  Next, in the conditioning process, the battery 100 is initially charged. At that time, a gas such as hydrogen is generated in the battery case 110. For this reason, the internal pressure of the battery case 110 becomes higher than before the conditioning process (the degree of decompression in the battery case 110 becomes low).

  Next, an airtight inspection process is performed on the battery 100. That is, the airtightness between the covering member 181 of the sealing member 180 and the hole surrounding portion 113m of the battery case 110 (the case lid member 113) is inspected. This airtight inspection process is performed at a temperature lower than the first temperature range (13 to 200 ° C. in the first embodiment) unlike the above-described temporary sealing process to the main sealing process. In addition, due to a decrease in elasticity of the insertion member 183, the environmental temperature (this embodiment 1) within a second temperature range (9 ° C. or less in this embodiment 1) in which the temporary sealing of the liquid injection hole 170 by the insertion member 183 cannot be maintained. Then, it is performed at −5 ° C.). As described above, the rubber-like elastic body forming the insertion member 183 clearly decreases in elasticity at 9 ° C. or less and almost disappears at 0 ° C. or less. Therefore, the rubber-like elastic body is cured under the temperature environment of −5 ° C. (It becomes a glass state) and the elasticity is almost lost. For this reason, the adhesiveness between the contact portion 183t of the insertion member 183 and the corner portion 171fa of the liquid injection hole 170 is almost lost, and the gas can flow between the insertion member 183 and the liquid injection hole 170.

  In this airtightness inspection process, the battery 100 is placed in a vacuum chamber under a temperature environment of −5 ° C., and the vacuum chamber is depressurized. Then, a hydrogen gas detector (Hydrogen Leak Detector H2000: manufactured by Sensister Co., Ltd.) is installed in the vicinity of the sealing member 180, and hydrogen gas is detected for 120 seconds. As described above, the hydrogen gas generated during the initial charge exists in the battery case 110. For this reason, when sealing failure has arisen between the peripheral part 181m of the coating | coated member 181 and the hole surrounding part 113m of the battery case 110, this hydrogen gas is inserted so that gas can be circulated. It leaks to the outside of the battery case 110 through between the member 183 and the liquid injection hole 170 and between the peripheral edge portion 181m of the covering member 181 with poor sealing and the hole peripheral portion 113m of the battery case 110. Therefore, if hydrogen gas can be detected by the hydrogen gas detector, it can be seen that a sealing failure has occurred between the peripheral portion 181 m of the covering member 181 and the hole peripheral portion 113 m of the battery case 110. Therefore, the batteries with poor sealing are excluded, and only good batteries 100 without defective sealing are selected. Thus, the battery 100 is completed.

  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 outside of the battery 100, the electrode body 120, and the electrolytic solution 117 accommodated therein. And a sealing member 180 formed by sealing the liquid injection hole 170 in an airtight manner. Among these, the sealing member 180 is made of a rubber-like elastic body, and the insertion member (insertion portion) 183 inserted into the liquid injection hole 170 and the liquid injection hole 170 in the battery case 110 while covering the insertion member 183 from the outside. And a covering member (covering portion) 181 that is airtightly and annularly joined to an annular hole surrounding portion 113m that surrounds the periphery.

  And the manufacturing method of the battery 100 which concerns on this Embodiment 1 press-fits the insertion member 183 into the injection hole 170 from the outside, and temporarily seals the injection hole 170 airtightly, and an insertion member after that. The main sealing step of airtightly and annularly joining the covering member 181 to the hole peripheral portion 113m of the battery case 110 while covering the outer surface 183, and then between the covering member 181 and the hole peripheral portion 113m of the battery case 110. An airtight inspection process for inspecting airtightness. Then, from the temporary sealing step to the main sealing step, a first temperature range (13 to 200 in the first embodiment) in which the liquid injection hole 170 can be temporarily sealed with the insertion member 183 by the elasticity of the insertion member 183. )) Within the ambient temperature (25 ° C. in the first embodiment). On the other hand, the hermetic inspection step is performed at a second temperature range (this embodiment) in which the temporary sealing of the liquid injection hole 170 by the insertion member 183 cannot be maintained due to the lower temperature of the first temperature range and the elasticity of the insertion member 183. In the first embodiment, it is performed at an environmental temperature within the range of 9 ° C. or lower (−5 ° C. in the first embodiment).

  As described above, in the method for manufacturing the battery 100, the first temperature at which the injection hole 170 can be temporarily sealed airtight by the insertion member 183 by the elasticity of the insertion member 183 from the temporary sealing step to the main sealing step. It is performed at an environmental temperature (25 ° C. in the first embodiment) within a range (13 to 200 ° C. in the first embodiment). For this reason, the liquid injection hole 170 can be hermetically sealed by the insertion member 183 in the temporary sealing step. In addition, it is possible to prevent the electrolyte solution 117 accommodated in the battery case 110 from leaking to the outside of the battery case 110 (such as the hole surrounding portion 113m) through the liquid injection hole 170 after the temporary sealing until the main sealing. . Therefore, during the main sealing process, the electrolyte solution 117 leaked from the injection hole 170 enters between the covering member 181 of the sealing member 180 and the hole peripheral portion 113m of the battery case 110, resulting in poor sealing. Generation | occurrence | production can be prevented and the coating | coated member 181 and the hole surrounding part 113m can be joined reliably.

  On the other hand, in the airtight inspection process, the liquid injection hole 170 is temporarily sealed by the insertion member 183 due to a lower temperature than the first temperature range (13 to 200 ° C. in the first embodiment) and due to a decrease in elasticity of the insertion member 183. Is performed at an environmental temperature (-5 ° C. in the first embodiment) within a second temperature range (9 ° C. or lower in the first embodiment) in which it is not possible to maintain. For this reason, during this airtight inspection process, temporary sealing cannot be maintained, the airtightness between the insertion member 183 and the liquid injection hole 170 is lowered, and the gas between the insertion member 183 and the liquid injection hole 170 is gas. Is ready for distribution. Therefore, by checking whether or not the gas in the battery case 110 leaks out of the battery case 110, the airtightness between the covering member 181 and the hole peripheral portion 113m of the battery case 110 can be easily and reliably obtained. Can be inspected. And the battery in which the sealing defect has arisen among these can be excluded reliably. Therefore, the airtight reliability between the covering member 181 of the sealing member 180 and the hole peripheral portion 113m of the battery case 110 is high, and the liquid injection hole 170 is hermetically sealed with the sealing member 180 (the covering member 181) for a long period of time. The battery 100 that can be sealed can be easily and reliably manufactured. Therefore, the battery 100 in which the airtightness between the covering member 181 of the sealing member 180 and the battery case 110 is inspected easily and reliably can be manufactured.

  Furthermore, in the first embodiment, the rubber-like elastic body includes a temperature range in which the first temperature range is 20 to 35 ° C., and at least partly overlaps with the temperature range in which the second temperature range is −50 to 10 ° C. Made of material. By forming the insertion member 183 with a rubber-like elastic body made of such a material, the environmental temperature within the temperature range of 20 to 35 ° C. from the temporary sealing step to the main sealing step (25 ° C. in the first embodiment). ), And the environmental temperature of these processes does not have to be extremely high or low. Therefore, these steps can be easily performed, and the manufacturing cost can be reduced. In addition, in the temperature range of −50 to 10 ° C., the ambient temperature in the temperature range of −50 to 9 ° C. that overlaps the second temperature range (9 ° C. or less in the present embodiment 1) (this embodiment). 1 is −5 ° C.), and the ambient temperature in the airtightness inspection process does not have to be extremely high or low. Therefore, the airtight inspection process can be easily performed, and the manufacturing cost can be reduced.

  Moreover, in this Embodiment 1, a temporary sealing process is performed under pressure reduction and this sealing process is performed under atmospheric pressure. By performing the temporary sealing step under reduced pressure, the inside of the battery case 110 after temporary sealing can be brought into a reduced pressure state (negative pressure). For this reason, it is possible to prevent the internal pressure of the battery case 110 from increasing early even if gas is generated in the battery case 110 during the conditioning process (initial charging process) performed after the main sealing process or in subsequent use. . On the other hand, since the main sealing step for performing welding is performed under atmospheric pressure, the main sealing step can be performed more easily than when performed under reduced pressure.

(Test results)
Next, the results of tests conducted to confirm the effects of the present invention will be described. In this test, in order to easily and reliably perform the test, the electrode body, the insulating film enclosure, and the electrolytic solution are not accommodated in the battery case, but only for the battery case, the positive electrode terminal, the negative electrode terminal, and the sealing member. A battery was produced. Moreover, piping was attached to the case main body member of the battery case so that gas could be supplied into the battery case from the outside of the battery.

  A test battery was prepared using the same battery case 110, positive electrode terminal 150, negative electrode terminal 160, and sealing member 180 as in the first embodiment as the test battery 1. However, in this sealing step, the entire periphery of the peripheral portion 181m of the covering member 181 of the sealing member 180 is not welded to the hole peripheral portion 113m of the battery case 110 in an annular shape, but the peripheral portion of the peripheral portion 181m. 90% of the direction was welded to form a C-shaped weld around the hole periphery 113m. Therefore, the test battery 1 is in a state in which gas can flow between the covering member 181 and the hole surrounding portion 113m, and the welding between the covering member 181 and the hole surrounding portion 113m is performed in the main sealing step. This corresponds to a state in which a sealing failure has occurred.

  In addition, as the test battery 2, the material of the insertion member is changed from the above-mentioned perfluoroelastomer to ethylene propylene diene rubber (EPDM) (glass transition point Tg = −50 to −40 ° C.), otherwise the embodiment. A test battery was manufactured using the same sealing member as in Example 1, and the battery case 110, the positive electrode terminal 150, and the negative electrode terminal 160 were the same as in the first embodiment. Similarly to the test battery 1, the test battery 2 is also welded in the circumferential direction 90% of the peripheral portion of the covering member of the sealing member, and C-shaped welding is performed around the hole of the battery case. Part was formed. Therefore, this test battery 2 is also in a state where gas can flow between the covering member and the hole peripheral portion (corresponding to a sealing failure).

  Next, an airtight test was performed on these test batteries 1 and 2. Specifically, gas (specifically, helium gas) is sent into the battery cases of these test batteries 1 and 2, and a helium gas detector detects a gas leak (helium gas leak amount) from the vicinity of the sealing member. It measured using. This measurement was performed while gradually reducing the environmental temperature from 25 ° C to -30 ° C. The result is shown in FIG.

As is apparent from the graph of FIG. 9, in the test battery 1, the environmental temperature was 13 ° C. or higher, and the amount of helium gas leaked was very small (about 1.0 × 10 ⁻⁹ ). On the other hand, when the environmental temperature was 9 ° C. or less, the amount of helium gas leaked significantly (about 1.0 × 10 ⁻⁵ ). Further, the amount of leakage in this low temperature environment was almost constant regardless of the temperature.
On the other hand, the test battery 2 has a very small amount of helium gas leakage (about 1.0 × 10 ⁻⁹ ) at any environmental temperature from 25 ° C. to −30 ° C. It was almost constant regardless of the temperature.

  The reason for producing such a test result is considered as follows. As described in the first embodiment, the rubber-like elastic body (perfluoroelastomer) used as the insertion member used in the test battery 1 is clearly cured and elastic when the environmental temperature is lowered to 9 ° C. Begins to decline. On the other hand, when the environmental temperature is 13 ° C. or higher, the insertion member is sufficiently elastic, so that the insertion member and the liquid injection hole are in close contact with each other and are hermetically sealed (temporarily sealed). Therefore, the helium gas sent into the battery case cannot pass between the insertion member and the liquid injection hole, and the helium gas does not leak out of the battery. For this reason, when the environmental temperature is 13 ° C. or higher, almost no leakage of helium gas is observed.

  On the other hand, the elasticity of the insertion member is reduced under a temperature environment of 9 ° C. or less. When the environmental temperature is further lowered, the elasticity of the insertion member is almost lost. For this reason, the airtightness between the insertion member and the liquid injection hole is lost, temporary sealing cannot be maintained, and the gas can flow between the insertion member and the liquid injection hole. As described above, the test battery 1 is in a state in which gas can flow between the covering member and the hole periphery (a state corresponding to a sealing failure). Therefore, the helium gas sent into the battery case passes between the insertion member and the liquid injection hole, and further passes between the covering member and the hole peripheral portion and leaks out of the battery. For this reason, in the test battery 1, when the environmental temperature is 9 ° C. or less, it is considered that the leak amount of helium gas is remarkably increased.

  On the other hand, in the test battery 2, the rubber-like elastic body (EPDM) that forms the insertion member of the sealing member has a glass transition point Tg of −50 to −40 ° C. and a temperature range of −39 to 100 ° C. , Have sufficiently high elasticity. On the other hand, in the temperature range of −40 ° C. or less, the elasticity is clearly reduced. Since the environmental temperature (-30 to 25 ° C.) performed in the above-described airtightness test is higher than −39 ° C., the insertion member made of EPDM has sufficient elasticity in any case, and the insertion member and the liquid injection The space between the holes is hermetically sealed. Therefore, the helium gas sent into the battery case cannot pass between the insertion member and the liquid injection hole, and the helium gas does not leak out of the battery. For this reason, almost no leakage of helium gas is observed at any environmental temperature of −30 to 25 ° C.

  As described above, as can be seen from the results of the airtightness test for the test batteries 1 and 2, by placing the battery in a temperature environment in which the elasticity of the rubber-like elastic body constituting the insertion member is clearly reduced or eliminated, the insertion member and The temporary sealing with the liquid injection hole can be broken, and a gas can be circulated between them. Therefore, by performing the airtight inspection under such a temperature environment, the airtightness between the covering member and the hole peripheral portion can be easily and reliably inspected. Therefore, a battery with poor sealing can be eliminated, and a battery with high hermetic reliability between the covering member and the hole surrounding portion and capable of sealing the liquid injection hole with the sealing member over a long period of time can be 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 all or part (see FIG. 10).

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, since the battery 100 can hermetically seal the liquid injection hole 170 with the sealing member 180 for a long period of time, the durability of the automobile 700 can be increased.

(Embodiment 3)
Next, a third embodiment will be described. A hammer drill 800 according to the third embodiment is a battery-using device on which the battery 100 according to the first embodiment is mounted (see FIG. 11). 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, since the battery 100 can hermetically seal the liquid injection hole 170 with the sealing member 180 for a long period of time, the durability of the hammer drill 800 can be 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. Examples of the through hole include a vent hole for venting gas from the battery case. 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. In the first embodiment, the form of the “through hole” is a stepped circular hole, but the form of the through hole can be changed as appropriate.

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 the first embodiment, the “sealing member” is an example in which the covering member (covering portion) 181 and the insertion member (inserting portion) 183 are integrated, but the covering portion and the inserting portion are separated. Can also be formed. Further, the shape and size of the covering portion and the shape and size of the insertion portion can be appropriately changed.

  In the first embodiment, the covering member 181 made of the same material (aluminum) as the battery case 110 is exemplified as the “covering portion”, but the material of the covering portion can be changed as appropriate. In Embodiment 1, the covering member 181 is fixed to the battery case 110 by welding, but the fixing method is not limited thereto. For example, the covering portion may be fixed to the battery case using a brazing material, solder, an adhesive, or the like.

  In Embodiment 1, the truncated cone-shaped insertion member 183 is exemplified as the “insertion portion” of the sealing member, but the shape and size of the insertion portion can be changed as appropriate. In the first embodiment, the insertion member 183 made of perfluoroelastomer is exemplified as the “insertion portion”, but the material of the rubber-like elastic body forming the insertion portion is not limited to this. Examples of the rubbery elastic material include acrylic rubber (ACM), nitrile rubber (NBR), isoprene rubber (IR), urethane rubber (U), ethylene propylene rubber (EPM, EPDM), and chlorosulfonated polyethylene (CSM). Epichlorohydrin rubber (CO, ECO), chloroprene rubber (CR), silicone rubber (Q), styrene-butadiene rubber (SBR), butadiene rubber (BR), fluororubber (FKM), butyl rubber (IIR), and the like.

  Among these materials, a material that includes a temperature range of 20 to 35 ° C. in the first temperature range and that overlaps at least partially with a temperature range of −50 to 10 ° C. in the second temperature range is selected. Particularly preferred. This is because it is not necessary to perform the temporary sealing process to the main sealing process and the airtight inspection process at an extremely high environmental temperature or a low environmental temperature.

In the first embodiment, the case where the environmental temperature from the “temporary sealing step” to the “main sealing step” is 25 ° C. is illustrated. However, this environmental temperature penetrates through the insertion portion due to the elasticity of the insertion portion. It can be appropriately changed within a first temperature range in which the holes can be hermetically sealed.
In the first embodiment, the “temporary sealing step” is performed under reduced pressure, but this can also be performed under atmospheric pressure.

Further, in the first embodiment, the case where the environmental temperature at which the “airtight inspection process” is performed is set to −5 ° C., but the environmental temperature is lower than the first temperature range and the elasticity of the insertion portion is reduced. Thus, the temporary sealing of the through hole by the insertion portion can be appropriately changed within a temperature range in which it cannot be maintained.
In the first embodiment, as the “air tightness inspection process”, the battery 100 is placed under reduced pressure, and a gas detector is used to detect gas leakage from the inside of the battery case 110. Not limited to. For example, the battery 100 may be submerged in a liquid such as water, and gas leakage (bubbles) from the battery case 110 may be confirmed visually.

  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, in Embodiment 3, although the hammer drill 800 was illustrated as a battery use apparatus which mounts the battery 100 which concerns on this invention, 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 Cover Member 117 Electrolyte 120 Electrode 150 Positive Electrode 160 Negative Electrode 170 Injection Hole (Through Hole)
171 Inner cylindrical part 171fa Corner part 173 Outer cylindrical part 180 Sealing member 181 Covering member (covering part)
181m Peripheral part 181y (of covering member) Welding part 183 Inserting member (inserting part)
183f Side surface 183t Contact portion 700 Hybrid vehicle (vehicle)
710 battery pack 800 hammer drill (equipment using batteries)
810 Battery pack

Claims (3)

A battery case having a through-hole communicating with the inside and outside of itself;
An electrode body housed in the battery case;
An electrolyte contained in the battery case;
A sealing member formed by airtightly sealing the through hole from the outside of the battery case,
An insertion portion made of a rubber-like elastic body and inserted into the through hole, and
A sealing member having a covering portion formed by airtightly and annularly joining an annular hole surrounding portion surrounding the through hole in the battery case while covering the insertion portion from the outside. A manufacturing method comprising:
A temporary sealing step of press-fitting the insertion portion from the outside into the through-hole of the battery case in which the electrolytic solution is stored, and temporarily sealing the through-hole in the insertion portion;
After the temporary sealing step, the main sealing step of airtightly and annularly joining the covering portion to the hole peripheral portion of the battery case, while covering the insertion portion from the outside,
After the main sealing step, an airtight inspection step for inspecting the airtightness between the covering portion of the sealing member and the hole peripheral portion of the battery case, and
From the temporary sealing step to the main sealing step,
Due to the elasticity of the insertion part, the insertion part is performed at an environmental temperature within a first temperature range in which the through hole can be airtightly sealed temporarily,
The airtight inspection process,
Lower than the first temperature range, and
A method of manufacturing a battery, which is performed at an environmental temperature within a second temperature range in which temporary sealing of the through hole by the insertion portion cannot be maintained due to a decrease in elasticity of the insertion portion. A battery manufacturing method according to claim 1, comprising:
The rubber-like elastic body is
The first temperature range includes a temperature range of 20 to 35 ° C, and
The battery manufacturing method which consists of a material with which the said 2nd temperature range overlaps with the temperature range of -50-10 degreeC at least partially. A method for producing a battery according to claim 1 or claim 2,
The temporary sealing step is performed under reduced pressure,
The main sealing step is a battery manufacturing method performed under atmospheric pressure.

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