JP2013254660A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To open a pressure release valve at a proper releasing pressure.SOLUTION: A large-diameter section 21 for housing a pressure release valve 23 is formed on an electrolyte injection hole 18 formed on a battery case can. Then, when the pressure release valve 23 is housed in the large-diameter section 21, a liquid-like gasket is applied between the pressure release valve 23 and the large-diameter section 21 so as to form a sealing layer 28. Thereby, the pressure release valve 23 is held by the sealing layer 28 comprising the liquid-like gasket, and housed in the large-diameter section 21. The sealing layer 28 is formed by the liquid-like gasket, and therefore, a reaction force given to the pressure release valve 23 can be made smaller. Accordingly, variation of a releasing pressure of the pressure release valve 23 can be restrained.

Description

  The present invention relates to a power storage device in which an electrode assembly and an electrolytic solution are housed in a battery case.

  A vehicle such as an EV (Electric Vehicle) or a PHV (Plug in Hybrid Vehicle) is equipped with a secondary battery such as a lithium ion battery as a power storage device that stores power supplied to an electric motor serving as a prime mover. This type of secondary battery is disclosed in Patent Document 1, for example. The secondary battery is an electrode in which a negative electrode in which a negative electrode active material is applied to a metal foil and a positive electrode in which a positive electrode active material is applied to a metal foil are insulated with a separator made of a microporous film and laminated in layers. Having an assembly. And a secondary battery is comprised by accommodating an electrode assembly and electrolyte solution in a battery case. The battery case of the secondary battery is provided with a pressure release valve that opens when the pressure in the battery case rises. In the secondary battery of Patent Document 1, a plurality of stamps that function as pressure release valves are formed on a sealing plug that seals an injection port of an electrolytic solution.

JP 2010-86776 A

  In the secondary battery of Patent Document 1, a sealing plug having a pressure release valve is attached to the lid by welding. However, when the pressure release valve is directly welded, the open pressure of the pressure release valve may change due to the welding heat. This is due to softening of the constituent material of the pressure relief valve under the influence of welding heat. When the release pressure of the pressure release valve changes, the pressure release valve cannot be opened with an appropriate release pressure.

  On the other hand, when the pressure release valve is not directly welded, it is conceivable to suppress the leakage of the electrolyte from the battery case, for example, by fixing a sealing material such as an O-ring to the battery case. However, it is difficult to support the pressure relief valve with a uniform load by the sealing material as described above. As a result, the pressure release valve is fixed to the battery case in a state where a stress such as twisting is applied by the elastic force of the sealing material. Accordingly, in this case as well, there is a possibility that the opening pressure of the pressure release valve changes as in the case of direct welding, and the pressure release valve cannot be opened with an appropriate opening pressure.

  This invention was made paying attention to the problem which exists in such a prior art, and the objective is to provide the electrical storage apparatus which can open | release a pressure release valve by appropriate open pressure.

  In order to solve the above-described problems, the invention according to claim 1 is an electric storage device in which an electrode assembly and an electrolytic solution are housed in a battery case, and an opening that communicates the inside and outside of the battery case, and the opening A pressure release valve that is disposed on the pressure vessel and opens when the internal pressure of the battery case exceeds the open pressure, and is disposed over the pressure release valve and fixes the pressure release valve to the battery case. Apply an adhesive between the fixing member and the pressure release valve and the battery case, or between the pressure release valve and the fixing member, and between the battery case and the fixing member, or both of them. And a sealing layer formed as described above.

  According to this, a pressure release valve is hold | maintained at a battery case can through the sealing layer formed by apply | coating an adhesive agent. The pressure release valve is fixed to the battery case can via a fixing member. For this reason, it is difficult for the pressure release valve to be given an external factor that causes a change in the release pressure. As a result, a change in the opening pressure of the pressure release valve can be suppressed. Therefore, even when the internal pressure of the battery case can rise, the pressure release valve can be opened with an appropriate opening pressure.

  In addition, in invention of Claim 1, when a seal layer is formed only between a pressure release valve and a battery case, between a pressure release valve and a fixing member, and between a battery case and a fixing member, Including a case where a seal layer is formed on both. Further, in the invention according to claim 1, a seal layer is further formed between each of the pressure release valve and the battery case, between the pressure release valve and the fixed member, and between each of the battery case and the fixed member. Including cases where

  The invention according to claim 2 is summarized in that in the power storage device according to claim 1, the adhesive is a liquid gasket. According to this, the reaction force applied to the pressure release valve can be made smaller by forming the seal layer with the liquid gasket. Therefore, the pressure release valve can be opened with an appropriate opening pressure.

  The invention according to claim 3 is the power storage device according to claim 1 or 2, wherein the opening is formed with an accommodation recess for accommodating the pressure release valve. According to this, by holding the pressure release valve in the housing recess, it is possible to suppress the displacement of the pressure release valve and the like, and to reliably open the battery case when the internal pressure of the battery case exceeds the open pressure.

  Invention of Claim 4 makes it a summary for the electrical storage apparatus as described in any one of Claims 1-3, and the said fixing member is welded to the said battery case can. According to this, since welding is performed on the fixed member, the influence of heat during welding does not directly affect the pressure release valve. As a result, a change in the opening pressure of the pressure release valve can be suppressed. Therefore, even when the internal pressure of the battery case can rise, the pressure release valve can be opened with an appropriate opening pressure.

  The gist of a fifth aspect of the present invention is the power storage device according to any one of the first to fourth aspects, wherein the opening is an injection hole for injecting the electrolytic solution. According to this, after assembling the power storage device, the injection hole necessary for injecting the electrolyte into the battery case can be used to arrange the pressure release valve that suppresses the increase in the internal pressure of the battery case. . Therefore, the configuration of the battery case can be simplified.

  A sixth aspect of the present invention is summarized as the power storage device according to any one of the first to fifth aspects, wherein the power storage device is a secondary battery. According to this, even when the internal pressure of the battery case can rise in the secondary battery, the pressure release valve can be opened with an appropriate opening pressure.

  According to the present invention, the pressure release valve can be opened with an appropriate opening pressure.

The perspective view which shows the external appearance of a secondary battery. The top view which shows the principal part of the cover member of the state which sealed the injection hole. FIG. 1 is a sectional view taken along line 1-1 of FIG. (A) is a schematic cross section which shows a mode that electrolyte solution is inject | poured into an injection hole, (b) is a schematic cross section which shows a mode that a pressure release valve is attached to a cover member. The schematic cross section which shows a mode that a fixing member is welded to a cover member. Sectional drawing explaining another example. Sectional drawing explaining another example.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, in a secondary battery 10 as a power storage device, an electrode assembly 12 is accommodated in a battery case 11. The battery case 11 includes a rectangular parallelepiped main body member 13 and a rectangular flat plate-shaped lid member 14. The lid member 14 closes the insertion port of the main body member 13 into which the electrode assembly 12 is inserted. Both the main body member 13 and the lid member 14 constituting the battery case can 11 are made of metal (for example, stainless steel or aluminum). Further, the secondary battery 10 of the present embodiment is a prismatic battery whose appearance is square. Further, the secondary battery 10 of the present embodiment is a lithium ion battery.

  A positive electrode terminal 15 and a negative electrode terminal 16 for taking out electricity from the electrode assembly 12 are electrically connected to the electrode assembly 12. The positive electrode terminal 15 and the negative electrode terminal 16 are respectively attached with ring-shaped insulating rings 17 a for insulating from the battery case can 11.

  The electrode assembly 12 includes a positive electrode, a negative electrode, and a separator that insulates the positive electrode from the negative electrode. The positive electrode is configured by applying a positive electrode active material on both surfaces of a positive electrode metal foil (aluminum foil). The negative electrode is configured by applying a negative electrode active material on both surfaces of a negative electrode metal foil (copper foil). The electrode assembly 12 has a stacked structure in which a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked and a separator is interposed between the electrodes. In addition, as shown in FIG. 3, the battery case 11 of the secondary battery 10 is formed with an injection hole 18 for injecting an electrolyte into the battery case 11 (main body member 13). As shown in FIG. 1, the injection hole 18 serving as an opening that communicates the inside and outside of the battery case can 11 is sealed with a sealing member 19.

  As shown in FIG. 3, the injection hole 18 penetrates the lid member 14 in the plate thickness direction. The injection hole 18 has a small-diameter portion 20 formed on the inner side of the battery case can 11 and a large-diameter portion 21 as an accommodation recess formed on the outer side of the battery case can 11. The small diameter part 20 and the large diameter part 21 are holes each having a circular shape in plan view. The small diameter portion 20 communicates with the step portion 22 of the large diameter portion 21. A pressure release valve 23 is accommodated in the large-diameter portion 21 as the accommodating recess.

  The sealing member 19 includes a pressure release valve 23 and a fixing plate 24 as a fixing member that fixes the pressure release valve 23 accommodated in the large diameter portion 21 to the lid member 14. As shown in FIGS. 2 and 3, the pressure release valve 23 has a disk shape and is made of metal such as aluminum or stainless steel. The plate thickness of the pressure release valve 23 is slightly thinner than the depth of the large diameter portion 21 that accommodates the pressure release valve 23. Further, the outer diameter of the pressure release valve 23 is slightly smaller than the inner diameter of the large diameter portion 21.

  A plurality (three in this embodiment) of grooves (recesses) 25 extending in the radial direction from the center of the pressure release valve 23 toward the outer peripheral surface are formed on the outer surface 23 a and the inner surface 23 b of the pressure release valve 23. Yes. The outer surface 23 a of the pressure release valve 23 is a surface facing the outside of the battery case 11 in the state accommodated in the large diameter portion 21, and the inner surface 23 b of the pressure release valve 23 faces the inside of the battery case 11. It is a surface. The plurality of grooves 25 are formed at equal intervals in the circumferential direction. Further, as shown in FIG. 3, the pressure release valve 23 is formed with a thin portion 26 whose thickness is partially reduced by the groove 25. In this way, the pressure release valve 23 partially having the thin portion 26 is opened when the thin portion 26 breaks when the internal pressure of the battery case 11 exceeds the open pressure. The battery case 11 is prevented from rupturing or the like by reducing the internal pressure by opening the pressure release valve 23. The opening pressure is a constant pressure. And the thin part 26 is set to the plate | board thickness which can be fractured | ruptured by the open pressure of the pressure release valve 23 determined at the design stage. Therefore, the groove 25 is formed with a depth that leaves the thickness of the thin portion 26 from the thickness of the pressure release valve 23.

  As shown in FIGS. 2 and 3, the fixed plate 24 is formed in an annular plate shape. The outer diameter of the fixed plate 24 is formed larger than the outer diameter of the pressure release valve 23. Further, the inner diameter of the fixed plate 24 is formed to be the same as the inner diameter of the small diameter portion 20. That is, the inner diameter of the fixed plate 24 is smaller than the outer diameter of the pressure release valve 23. The fixing plate 24 is made of metal such as aluminum or stainless steel.

  The pressure release valve 23 and the fixing plate 24 are attached to the lid member 14 as shown in FIG. Specifically, the pressure release valve 23 is accommodated in the large diameter portion 21 of the injection hole 18. Each groove 25 of the pressure release valve 23 is arranged immediately above the small diameter portion 20 when the pressure release valve 23 is accommodated in the large diameter portion 21.

  On the other hand, the fixing plate 24 is disposed so as to cover the pressure release valve 23 accommodated in the large-diameter portion 21 and the lid member 14 around it. The fixing plate 24 is disposed on the outer surface 14a of the lid member 14 so that the annular portion does not overlap the thin portion 26 that functions as a valve. That is, the fixing plate 24 is disposed so as to cover the large-diameter portion 21 that houses the pressure release valve 23. The fixing plate 24 is fixed to the lid member 14 by welding. As shown in FIG. 2, the fixing plate 24 is welded at three locations, and is fixed to the lid member 14 via a welded portion 27 formed by the welding. That is, in this embodiment, the pressure release valve 23 is not directly fixed to the lid member 14 by welding, but is fixed by the fixing plate 24 that is fixed to the lid member 14 by welding.

  And in this embodiment, in order to prevent the electrolyte solution and gas in the battery case 11 from leaking, more specifically speaking, the large-diameter portion of the injection hole 18 between the battery case 11 and the pressure release valve 23. A seal layer 28 is formed between 21 and the pressure release valve 23. The seal layer 28 is formed by applying a liquid gasket as an adhesive to the step portion 22 of the large diameter portion 21. The step portion 22 between the battery case 11 and the pressure release valve 23 is a portion that can be a leakage portion that may pass when the electrolyte leaks to the outside. Further, the seal layer 28 made of a liquid gasket also serves as a joint for joining the pressure release valve 23 to the large diameter portion 21. And the sealing layer 28 by a liquid gasket has a small reaction force given to the pressure release valve 23 which contacts the said sealing layer 28 compared with the case where a sealing layer is formed with the O-ring etc. which are formed with a rubber material. Thereby, the pressure release valve 23 is fixed to the battery case 11 in a state in which the release pressure is hardly changed by the reaction force from the seal layer 28.

Next, a method for manufacturing the secondary battery 10 will be described.
After the electrode assembly 12 is inserted into the main body member 13, the insertion opening of the main body member 13 is closed by the lid member 14. Thereafter, as shown in FIG. 4A, an electrolytic solution injection nozzle 30 is inserted into the injection hole 18 in the battery case 11, and the electrolytic solution is injected into the battery case 11 through the injection nozzle 30. Is done.

  And after injection | pouring of electrolyte solution, as shown in FIG.4 (b), a liquid gasket is apply | coated to the level | step-difference part 22 of the large diameter part 21, and the sealing layer 28 is formed. The application amount of the liquid gasket is adjusted so that the outer surface 23a of the pressure release valve 23 and the outer surface 14a of the lid member 14 are substantially flush with each other when the pressure release valve 23 is accommodated in the large diameter portion 21. In other words, since the plate thickness of the pressure release valve 23 is smaller than the depth of the large diameter portion 21, the liquid gasket is applied by an amount that fills the difference. And after application | coating of a liquid gasket, the large diameter part 21 accommodates the pressure release valve 23, as shown in FIG.4 (b).

  In addition, after the pressure release valve 23 is accommodated, a fixing plate 24 is disposed on the outer surface 23a side of the pressure release valve 23 as shown in FIG. Then, the fixing plate 24 is welded by irradiation with the laser 31. In this embodiment, welding is performed on the fixed plate 24. For this reason, the pressure release valve 23 is not easily affected by heat during welding. By the procedure described above, the pressure release valve 23 and the fixing plate 24 are fixed to the lid member 14 and hermetically seal the injection hole 18. That is, in the present embodiment, the fixing plate 24 is directly fixed to the lid member 14 of the battery case can 11, while the pressure release valve 23 is fixed to the lid member 14 of the battery case can 11. It is indirectly fixed by.

Next, the effect | action of the secondary battery 10 of this embodiment is demonstrated.
When the internal pressure of the battery case 11 exceeds the open pressure, the thin part 26 breaks and the pressure release valve 23 lowers the internal pressure of the battery case 11. The pressure release valve 23 of this embodiment is joined to the large diameter portion 21 by a seal layer 28 made of a liquid gasket. The pressure release valve 23 is fixed to the lid member 14 by welding the fixing plate 24 to the lid member 14. For this reason, the pressure release valve 23 is fixed in a state in which it is hardly affected by heat during welding. As a result, the pressure release valve 23 is in a state in which the opening pressure is unlikely to change when it is fixed, and is also in a state in which the opening pressure is unlikely to change after fixing. Therefore, the pressure release valve 23 can be opened when the internal pressure of the battery case 11 exceeds the open pressure determined in the design stage. That is, the pressure release valve 23 does not open at an unexpected pressure such as a pressure lower than the opening pressure determined at the design stage, and can be opened at an appropriate opening pressure.

Therefore, according to the present embodiment, the following effects can be obtained.
(1) The pressure release valve 23 is held in the battery case 11 through a seal layer 28 formed by applying a liquid gasket. Further, the pressure release valve 23 is fixed to the battery case can 11 via a fixing plate 24. Therefore, it is difficult for the pressure release valve 23 to be provided with an external factor that causes a change in the release pressure, that is, a reaction force of the seal layer 28 or heat during welding. As a result, a change in the opening pressure of the pressure release valve 23 can be suppressed. Therefore, even when the internal pressure of the battery case 11 rises, the pressure release valve 23 can be opened with an appropriate opening pressure.

  (2) Since the seal layer 28 is formed of a liquid gasket, the reaction force applied to the pressure release valve 23 can be made smaller. Therefore, the pressure release valve 23 can be opened with an appropriate opening pressure.

  (3) Liquid gaskets usually require time to cure. However, the manufacturing process of the secondary battery 10 includes processes that require time, such as a process of impregnating the electrode assembly 12 with the electrolytic solution and an aging process. Therefore, even if the sealing layer 28 is formed by a liquid gasket, the liquid gasket can be reliably cured before the secondary battery 10 is completed. That is, the liquid gasket can function reliably as the seal layer 28.

  (4) By holding the pressure release valve 23 in the large-diameter portion 21, the displacement of the pressure release valve 23 can be suppressed. Therefore, when the internal pressure of the battery case 11 exceeds the open pressure, the pressure release valve 23 can be reliably opened. That is, the pressure release valve 23 can reliably receive the internal pressure of the battery case 11 through the injection hole 18 and can operate appropriately.

  (5) The pressure release valve 23 is fixed by welding the fixing plate 24 to the battery case 11 (lid member 14). For this reason, heat at the time of welding is transmitted to the fixing plate 24, but is difficult to be directly transmitted to the pressure release valve 23. In other words, the influence of heat during welding does not directly affect the pressure release valve 23. As a result, a change in the opening pressure of the pressure release valve 23 can be suppressed. Therefore, even when the internal pressure of the battery case 11 rises, the pressure release valve 23 can be opened with an appropriate opening pressure.

  (6) Further, welding work can be simplified by welding the fixing plate 24 to the outer surface 14 a of the lid member 14. That is, in the manufacturing process of the secondary battery 10, the electrolytic solution is injected through the injection hole 18 before the fixing plate 24 is welded. At this time, the electrolytic solution may be scattered around the injection hole 18. For this reason, when welding the fixing plate 24, it is preferable to wipe off the electrolytic solution scattered on the welding surface. In the present embodiment, since the welding surface of the fixing plate 24 is the outer surface 14a of the lid member 14, the wiping operation of the electrolyte can be easily performed. As a result, the welding operation can be simplified.

  (7) The pressure release valve 23 is disposed in the injection hole 18. The injection hole 18 becomes a portion that is not required after the secondary battery 10 is assembled, that is, after injection of the electrolyte. For this reason, by using the injection hole 18 necessary for injecting the electrolytic solution into the battery case 11 to arrange the pressure release valve 23 that suppresses the increase in the internal pressure of the battery case 11, the battery case 11 The configuration can be simplified.

  (8) By mounting the secondary battery 10 of this embodiment on a vehicle, for example, the influence on the running performance of the vehicle can be reduced. That is, since the pressure release valve 23 is opened when the internal pressure of the battery case 11 rises abnormally to the assumed open pressure, the power supply from the secondary battery 10 can be stabilized.

In addition, you may change this embodiment as follows.
As shown in FIG. 6, the formation site of the seal layer 28 may be changed. In another example shown in FIG. 6, the seal layer 28 is formed between the inner peripheral surface of the large diameter portion 21 and the outer peripheral surface of the pressure release valve 23. This part is a part between the battery case 11 and the pressure release valve 23, and similarly to the part in which the seal layer 28 is formed in the embodiment, there is a possibility that the electrolyte may pass when leaking to the outside. It can be a part. The pressure release valve 23 is joined to the battery case 11 by a seal layer 28 formed between the outer peripheral surface thereof and the inner peripheral surface of the large diameter portion 21, and is held in the large diameter portion 21. In the case of another example shown in FIG. 6, the thickness of the pressure release valve 23 is set so that the pressure release valve 23 does not protrude from the outer surface 14 a of the lid member 14 when the pressure release valve 23 is accommodated in the large diameter portion 21. Is set. For example, the plate thickness of the pressure release valve 23 is the same as the depth of the large diameter portion 21. In this case, the outer surface 14a of the lid member 14 and the outer surface 23a of the pressure release valve 23 are flush with each other, which is preferable. Further, the outer diameter of the pressure release valve 23 and the inner diameter of the large diameter portion 21 are set in consideration of the thickness of the seal layer 28. In the case of another example shown in FIG. 6, a liquid gasket is applied to the inner peripheral surface of the large-diameter portion 21 after the electrolyte is injected to form a seal layer 28, and then the pressure release valve 23 is connected to the large-diameter portion 21. The fixing plate 24 is welded and fixed to the lid member 14.

  As shown in FIG. 7, the formation site of the seal layer 28 may be changed. In another example shown in FIG. 7, the seal layer 28 is formed between the outer surface 14 a of the lid member 14 and the outer surface 23 a of the pressure release valve 23, and the inner surface 24 a of the fixing plate 24 that contacts these outer surfaces 14 a and 23 a. ing. This part is a part between the battery case 11 and the fixing plate 24, and a part between the pressure release valve 23 and the fixing plate 24. Like the part where the seal layer 28 is formed in the embodiment, the electrolytic solution is outside. This is a part that can become a leaking part that may pass when leaking into the water. The pressure release valve 23 is formed by a sealing layer 28 formed between the outer surface 23a of the fixing plate 24 and the inner surface 24a of the fixing plate 24 and between the outer surface 14a of the lid member 14 and the inner surface 24a of the fixing plate 24. While being joined to the can 11 and the fixing plate 24, it is held in the large diameter portion 21. In the case of another example shown in FIG. 7, the thickness of the pressure release valve 23 is set so that the pressure release valve 23 does not protrude from the outer surface 14 a of the lid member 14 when the pressure release valve 23 is accommodated in the large diameter portion 21. Is set. For example, the plate thickness of the pressure release valve 23 is the same as the depth of the large diameter portion 21. In this case, the outer surface 14a of the lid member 14 and the outer surface 23a of the pressure release valve 23 are flush with each other, which is preferable. Further, the outer diameter of the pressure release valve 23 is set in accordance with the inner diameter of the large diameter portion 21. In the case of another example shown in FIG. 7, the pressure release valve 23 is accommodated in the large-diameter portion 21 after the electrolytic solution is injected, and thereafter the liquid is applied to each of the outer surface 14 a of the lid member 14 and the outer surface 23 a of the pressure release valve 23. A seal layer 28 is formed by applying a gasket. Then, the fixing plate 24 is fixed to the lid member 14 by welding.

  O About the formation site | part of the sealing layer 28 demonstrated by embodiment and the said another example, any one place may be sufficient and a combination may be sufficient. For example, you may combine between the cover member 14 and the pressure release valve 23 which comprise the battery case 11 shown in FIG. 3, and between the cover member 14 and the pressure release valve 23 shown in FIG. Further, the lid member 14 and the pressure release valve 23 shown in FIG. 3 may be combined with the lid member 14 and the fixing plate 24 and the pressure release valve 23 and the fixing plate 24 shown in FIG. good. Moreover, you may combine each formation member of the sealing layer 28 shown in FIG.6 and FIG.7. Moreover, you may combine each formation member of the sealing layer 28 shown in FIG.3, FIG6 and FIG.7. That is, the sealing layer 28 may be formed between the pressure release valve 23 and the lid member 14, between the pressure release valve 23 and the fixed plate 24, between the lid member 14 and the fixed plate 24, or both.

O You may provide separately in the battery case 11 the opening part which arrange | positions the pressure release valve 23, and the opening part which functions as an injection hole which inject | pours electrolyte solution.
(Circle) You may change the shape of the groove | channel 25 and the thin part 26 which are formed in the pressure release valve 23. FIG.

○ The appearance of the pressure release valve 23 and the fixed plate 24 may be changed. For example, it may be formed in a square plate shape in plan view.
O The adhesive forming the sealing layer 28 may be changed to another adhesive instead of the liquid gasket.

  In the battery case 11, an accommodation recess that can accommodate the fixing plate 24 may be further formed. The housing recess in this case has an inner diameter larger than the inner diameter of the large-diameter portion 21 that houses the pressure release valve 23. In this case, the injection hole 18 (opening) is formed with a large-diameter portion 21 that accommodates the pressure release valve 23 and another large-diameter portion that is connected to the large-diameter portion 21 and has a large inner diameter. The The injection hole 18 (opening) has a two-stage structure having two steps.

The fixing plate 24 may be fixed to the lid member 14 by another method instead of welding. For example, it may be fastened and fixed.
O The number of welded portions 27 when welding the fixed plate 24 may be changed. That is, the fixing plate 24 can be fixed by forming at least two welds 27. In addition, since the heat at the time of the welding will affect the pressure release valve 23 if the welding part 27 is increased too much, it is good to adjust moderately so that the welding part 27 may not be increased too much.

The present invention is not limited to the laminated secondary battery 10 as in the embodiment, and may be applied to a wound secondary battery in which a belt-like positive electrode and a belt-like negative electrode are wound and laminated in layers.
(Circle) the secondary battery 10 of embodiment may be mounted in a motor vehicle as a vehicle, and may be mounted in an industrial vehicle. Further, the present invention may be applied to a stationary power storage device.

The configuration of the present embodiment may be applied to other power storage devices such as electric double layer capacitors.
The secondary battery 10 is a lithium ion secondary battery, but is not limited thereto, and may be another secondary battery. In short, any ion may be used as long as ions move between the positive electrode active material layer and the negative electrode active material layer and transfer charge.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery, 11 ... Battery case can, 12 ... Electrode assembly, 18 ... Injection hole, 19 ... Sealing member, 20 ... Small diameter part, 21 ... Large diameter part, 23 ... Pressure release valve, 24 ... Fixed plate 27 ... welds, 28 ... seal layer.

Claims (6)

In a power storage device that houses an electrode assembly and an electrolyte in a battery case,
An opening communicating between the inside and outside of the battery case,
A pressure release valve disposed in the opening and opening when the internal pressure of the battery case can exceeds the open pressure;
A fixing member disposed over the pressure release valve and fixing the pressure release valve to the battery case,
It is formed by applying an adhesive between the pressure release valve and the battery case, or between the pressure release valve and the fixing member, and between the battery case and the fixing member, or both of them. A power storage device.   The power storage device according to claim 1, wherein the adhesive is a liquid gasket.   The power storage device according to claim 1 or 2, wherein an accommodation recess for accommodating the pressure release valve is formed in the opening.   The power storage device according to claim 1, wherein the fixing member is welded to the battery case can.   The power storage device according to claim 1, wherein the opening is an injection hole for injecting the electrolytic solution.   The power storage device according to any one of claims 1 to 5, wherein the power storage device is a secondary battery.