JP2015046309A - Gas discharge device and gas discharge method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas discharge device and a gas discharge method for discharging residual gas remaining inside a separator bag of an electrode unit.SOLUTION: A gas discharge device 1 allows residual gas A remaining inside a separator bag 90 of an electrode unit 80 to be discharged, the electrode unit 80 being configured by housing one electrode 81 from among cathode and anode inside a separator bag 90 formed by joining peripheral parts 91a of separators 91 covering both main surfaces of the electrode 81 except a part of the peripheral parts 91a. The gas discharge device 1 includes injection parts 11a for injecting pressure gas G that pressurizes, from the outside opposite to the inside, the peripheral part 91a of the separator 91 covering at least one main surface, and when viewed from a direction perpendicular to the main surface, is arranged so as to inject the pressure gas G toward the opening part 95 where the peripheral parts 91a of the separators 91 are not joined with each other.

Description

  The present invention relates to an electrode unit having a configuration in which an electrode is accommodated in a separator bag, and relates to a gas discharge device and a gas discharge method for discharging gas remaining inside the separator bag.

  2. Description of the Related Art A power storage device is known that includes an electrode assembly in which a positive electrode and a negative electrode are stacked via a separator. For example, as shown in Patent Document 1, an electrode unit housed in a separator bag is formed by sandwiching one of a positive electrode and a negative electrode between separators and then joining the peripheral edges of the separators together. There is an electrode assembly in which the other of the positive electrode and the negative electrode is disposed between these electrode units to prevent the positive electrode and the negative electrode from contacting each other.

  In such an electrode unit, gas tends to remain in a space enclosed by the separator bag (hereinafter referred to as “the inside of the separator bag”). If gas remains inside the separator bag, good contact between the active material and the electrolytic solution may be hindered. Therefore, as shown in Patent Document 1, a structure of an electrode unit for preventing gas from remaining inside the separator bag has been proposed.

JP 2011-009118 A

  However, if gas remains inside the separator bag, the thickness of the electrode unit increases, and in the next process of assembling the electrode assembly, there is a possibility that the electrode assembly cannot be stored in a casing of a prescribed size. Considering the next process, the electrode unit not only has a structure that easily discharges the gas remaining inside the separator bag, but also forcibly discharges the remaining gas to reduce the gas remaining inside the separator bag. It is desirable to make it.

  Therefore, an object of the present invention is to provide a gas discharge device and a gas discharge method for discharging residual gas remaining inside the separator bag of the electrode unit.

  A gas discharge device according to one aspect of the present invention includes one electrode of a positive electrode and a negative electrode, and a separator bag in which peripheral portions of a separator covering both main surfaces of the electrodes are joined except for a part of the peripheral portion. A gas exhaust device that targets an electrode unit and exhausts residual gas remaining inside a separator bag that accommodates an electrode, the outer periphery of the separator covering at least one main surface from the outer side opposite to the inner side While injecting the pressing gas to be pressed, when viewed from a direction perpendicular to the main surface, the pressing gas is injected toward the opening which is a part of the part where the peripheral portions of the separator are not joined to each other. The injection part arrange | positioned in is provided.

  In the gas discharge device having such a configuration, the residual gas remaining between the electrode and the separator is pushed out by being pressed from the outside of the separator. Since the pressurized gas is injected from the peripheral edge of the separator toward the opening, the residual gas is pushed out in the direction from the peripheral edge toward the opening. Thereby, the residual gas inside the separator bag is forcibly expelled from the opening. That is, the residual gas remaining inside the separator bag of the electrode unit can be discharged.

  Moreover, in one Embodiment, the opening part is provided in one place and the tab formed in the peripheral part of the electrode may protrude outside the separator bag from the opening part.

  In such a separator bag, the opening is provided only in one place, and the gas remaining inside the separator bag is particularly difficult to escape. In this apparatus, even the electrode unit having such a structure can discharge the gas inside the separator bag.

  Moreover, in one Embodiment, the injection part may be provided with two or more. In this case, the injection directions in which the injection unit injects the gas may intersect each other.

  In the gas discharge device having such a configuration, the gas inside the separator bag can be simultaneously expelled toward the opening, so that the gas inside the separator bag can be discharged more efficiently.

  Moreover, in one Embodiment, the injection part may be arrange | positioned so that a pressurization gas can be injected with respect to both the separators which cover a main surface.

  In the gas discharge device having such a configuration, the residual gas remaining between the electrode and one separator and the residual gas remaining between the electrode and the other separator can be simultaneously driven out toward the opening. Therefore, the residual gas inside the separator bag can be discharged more efficiently.

  Moreover, in one Embodiment, the injection part may be provided relatively movable with respect to the separator which covers at least one main surface.

  In the gas discharge device having such a configuration, the position of the separator pressed by the pressing gas can be moved from the peripheral edge of the separator toward the opening. As a result, the residual gas inside the separator bag can be moved toward the opening, and can be expelled from the opening more reliably.

  A gas discharge method according to one aspect of the present invention includes one electrode of a positive electrode and a negative electrode, and a separator bag in which peripheral portions of a separator covering both main surfaces of the electrodes are joined except for a part of the peripheral portion. A gas discharge method for exhausting residual gas remaining inside a separator bag that accommodates an electrode and containing an electrode, from the outer side opposite to the inner side, the peripheral portion of the separator covering at least one main surface While injecting the pressing gas to be pressed, when viewed from the direction perpendicular to the main surface, the pressing gas is injected toward the opening which is a part of the peripheral portions of the separator that are not joined to each other, Residual gas inside the separator bag is expelled to the opening by pressing the outer surface of the separator.

  In the gas discharge method having such a configuration, the gas remaining between the electrode and the separator is pushed out by being pressed from the outside of the separator. Since the pressurized gas is injected from the peripheral edge of the separator toward the opening, the residual gas is pushed out in the direction from the peripheral edge toward the opening. Thereby, the residual gas inside the separator bag is forcibly expelled from the opening. That is, the residual gas remaining inside the separator bag of the electrode unit can be discharged.

  Moreover, in one Embodiment, you may move the press position by press gas toward an opening part from a peripheral part by moving an electrode unit in the state pinched | interposed with the mesh member or the sheet | seat member.

  In the gas discharge method having such a configuration, the gas remaining inside the separator bag can be discharged from the opening, and the separator itself can be protected.

  According to the present invention, the residual gas remaining inside the separator bag of the electrode unit can be discharged.

It is the perspective view which showed an example of the positive electrode unit which the gas exhaust apparatus which concerns on one Embodiment makes object. It is a top view which shows the gas discharge apparatus which concerns on one Embodiment. It is sectional drawing in the III-III line | wire shown in FIG. It is explanatory drawing which showed a mode that the residual air inside a separator bag was discharged | emitted by the gas discharge apparatus 1. FIG. It is the graph which showed the procedure of the press with respect to an electrode assembly in an Example and a comparative example. It is the graph which showed the thickness of the electrode assembly measured in the Example. It is the graph which showed the thickness of the electrode assembly measured in the comparative example. It is sectional drawing which shows the gas discharge apparatus which concerns on other embodiment. It is sectional drawing which shows the gas discharge apparatus which concerns on other embodiment. It is sectional drawing which shows the gas discharge | emission method which concerns on other embodiment.

  Hereinafter, a gas discharge device 1 according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. The dimensional ratios in the drawings do not necessarily match those described. For convenience of explanation, XYZ coordinates are set in FIGS.

  FIG. 1 is a perspective view illustrating an example of a positive electrode unit (electrode unit) 80 targeted by the gas discharge device 1 according to an embodiment. First, the positive electrode unit 80 will be described. As shown in FIG. 1, the positive electrode unit (electrode unit) 80 includes a positive electrode plate (positive electrode / electrode) 81 and a separator bag 90 that accommodates the positive electrode plate 81.

  The positive electrode plate 81 includes a positive electrode metal foil 83 and a positive electrode active material layer 85 formed on both surfaces of the positive electrode metal foil 83. An example of the material of the positive electrode metal foil 83 is a metal such as aluminum. Although the thickness of the positive electrode metal foil 83 is not specifically limited, For example, it can be set to 5-25 micrometers.

  The positive electrode active material layer 85 includes a positive electrode active material and a binder, and may include a conductive additive as necessary. Although the thickness of the positive electrode active material layer 85 is not particularly limited, it can be set to, for example, 40 to 100 μm on one side.

  The positive electrode active material is not particularly limited as long as it is a positive electrode active material for a lithium ion secondary battery. Examples of the positive electrode active material include a lithium compound, a metal compound, and a polymer material. Examples of the binder are fluorine-containing resins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluororubber, thermoplastic resins such as polypropylene and polyethylene, imide resins such as polyimide and polyamideimide, and alkoxysilanol group-containing resins. The amount of the binder can be 1 to 30 parts by mass with respect to 100 parts by mass of the active material. Examples of the conductive aid are carbon-based particles such as carbon black, graphite, acetylene black (AB), ketjen black (registered trademark) (KB), and vapor grown carbon fiber (VGCF). These can be added alone or in combination of two or more. Although it does not specifically limit about the usage-amount of a conductive support agent, For example, it can be set as 1-30 mass parts with respect to 100 mass parts active material.

  The positive electrode metal foil 83 has a tab 87 on which the positive electrode active material layer 85 is not formed. The tab 87 protrudes outside the separator bag 90 from an opening 95 described later.

  The separator bag 90 includes a pair of rectangular separators 91 and 91 disposed so as to cover both main surfaces of the positive electrode plate 81, and a welded portion 93 in which end portions of the separators 91 and 91 are welded (joined) to each other. And an opening 95 in which the end portions of the separators 91 and 91 are not welded to each other. The opening 95 is provided at one place.

  An example of the material of the separator 91 is a porous film made of a thermoplastic resin such as polytetrafluoroethylene, polypropylene, or polyethylene. Although the thickness of the separator 91 is not specifically limited, For example, it can be 10-50 micrometers.

  The method for forming the welded portion 93 is not particularly limited. For example, if the positive electrode plate 81 is sandwiched between the separators 91 and 91 and the end portions of the separators 91 and 91 are sandwiched between heating members corresponding to the shape of the welded portion 93. good. At this time, it is preferable that the temperature of the heating member is equal to or higher than the melting point of the separator. Note that ultrasonic welding, high-frequency welding, or the like may be performed instead of thermal welding.

  Next, the gas discharge device 1 according to an embodiment will be described mainly with reference to FIGS. 2 and 3. FIG. 2 is a plan view showing the gas discharge device 1. 3 is a cross-sectional view taken along line III-III shown in FIG. The gas discharge device 1 mainly includes one nozzle group 11 having a plurality of nozzles (injection units) 11 a, a hose connector 15, and a tank 25.

  The nozzle group 11 is a portion that ejects air (pressed gas) to one separator 91 of the separator bag 90, and is provided to be movable in the XY plane. Specifically, it is movably provided between position P1, position P2, position P3, and position P4 shown in FIG.

  The nozzle group 11 has a plurality of (four in the present embodiment) nozzles 11a that each ejects air. The nozzle 11a injects air G that presses the peripheral edge 91a of one separator 91 from the outside of the separator bag 90, and also when viewed from a direction perpendicular to the main surface of the positive electrode plate 81 (see FIG. 2). When viewed from the Z-axis direction shown), the air gap G is disposed so as to be ejected toward the opening 95 which is a part of the separator 91 where the peripheral edge portions 91a are not joined to each other.

  As shown in FIG. 2, the injection directions (broken line directions) in which each nozzle 11a in the nozzle group 11 injects air intersect each other. Further, the jetting directions of air from the nozzles 11a at the respective positions P1 to P4 also intersect each other.

  One hose connector 15 is provided in each nozzle group 11 and functions as a compressed air distributor. The nozzle 11a and the hose connector 15 are connected by a flexible hose 17 and a pipe joint 19, respectively. Each hose connector 15 is provided with a valve 21 for adjusting the amount of compressed air supplied from the tank 25.

  The tank 25 is a part that supplies compressed air with adjusted pressure to the hose connector 15. The tank 25 and each nozzle group 11 are connected by a hose 27.

  Next, a method (gas discharge method) for discharging the residual air (residual gas) A remaining in the separator bag 90 by the gas discharge device 1 of the present embodiment will be described in detail mainly using FIG. FIG. 4 is an explanatory view showing a state in which the residual air A inside the separator bag 90 is discharged by the gas discharge device 1.

  As shown in FIG. 2, the positive electrode unit 80 targeted by the gas discharge device 1 is disposed at a predetermined position. In addition, the mounting part for mounting the positive electrode unit 80 may be provided as a part of the configuration of the gas discharge device 1. Next, the nozzle group 11 of the gas discharge device 1 is moved to the position P1, and the air G is ejected from the nozzle 11a. At this time, the position of the nozzle 11 a is adjusted so that the air G from the nozzle 11 a is sprayed to the peripheral edge portion 91 a of one separator 91. The position of the peripheral edge 91a to which the air G from the nozzle 11a is sprayed can be appropriately set based on the injection amount of the air G from the nozzle 11a, the injection angle α, and the like.

  One separator 91 to which the air G from the nozzle 11a is sprayed is pressed from the outside to the inside of the separator 91. Thereby, the residual air A between the positive electrode plate 81 and the separator 91 is pushed out in the pressing direction. As shown in FIG. 4B, since the air G is jetted from the peripheral edge 91 a of the separator 91 toward the opening 95, the residual air A is pushed out toward the opening 95. Thereby, as shown in FIG. 4C, the residual air A in the separator bag 90 is forced out of the opening 95. That is, the residual air A remaining in the separator bag 90 of the positive electrode unit 80 can be discharged. When the residual air A is discharged from the opening 95, the ejection of the air G from the nozzle 11a is stopped.

  Next, as shown in FIG. 2, the nozzle group 11 of the gas discharge device 1 is moved to the position P2, and the air G is ejected from the nozzle 11a again. Also in this case, the residual air A remaining in the separator bag 90 of the positive electrode unit 80 can be discharged by the same operation as described above. In this way, the residual air A remaining in the separator bag 90 of the positive electrode unit 80 can be discharged by the nozzle group 11 ejecting the air G from the nozzle 11a at the position P1, the position P2, the position P3, and the position P4. it can.

  Next, the point that the residual air A remaining in the separator bag 90 of the positive electrode unit 80 can be discharged by the gas discharge device 1 described above will be described based on Examples and Comparative Examples. In addition, this invention is not limited to the Example and comparative example which are shown below.

  In the present embodiment, first, residual air remaining in the separator bag 90 by the gas discharge device 1 having the configuration shown in FIGS. 2 and 3 described in the upper stage, with respect to the positive electrode unit 80 having the configuration shown in FIG. 1 described in the upper stage. A was discharged. The residual air A was discharged from both sides of the separator bag 90. That is, after the residual air A was discharged to one separator 91 by the above-described method, the remaining air A was discharged to the other separator 91 by the same method.

Next, 75 negative electrode plates each composed of a negative electrode metal foil and negative electrode active material layers formed on both surfaces of the negative electrode metal foil and 74 positive electrode units were alternately stacked to form an electrode assembly. In addition, the thickness of each member which comprises a negative electrode plate and a positive electrode unit was as follows.
<Negative electrode>
Negative electrode thickness: 0.0762 mm
75 sheets total thickness: 5.715mm
<Positive electrode unit>
Positive electrode thickness: 0.199444 mm
74 sheets total thickness: 5.715mm
Separator thickness: 0.0238mm
148 sheets total thickness: 3.5224mm
<Electrode assembly>
Total thickness: 23.9963mm

  Next, the electrode assembly was pressed according to the procedure shown in FIG. That is, for the target electrode assembly, a press pressure of 14.7 kN for 4 seconds, a press pressure of 0.98 kN for 4 seconds, a press pressure of 14.7 kN for 4 seconds, and a press pressure of 0.49 kN for 4 seconds. After holding, the thickness was measured. The measurement result of the thickness is as shown in FIG. The number on the horizontal axis indicates the sample number. In this example, it was confirmed that the thickness of the electrode assembly was within the target range in all samples.

  Next, a comparative example will be described. The comparative example is different from the embodiment in that the positive electrode unit 80 having the structure shown in FIG. 1 described in the upper part remains in the separator bag 90 by the gas discharge device 1 having the structure shown in FIGS. 2 and 3 described in the upper part. The residual air A was not discharged. The electrode assembly thus configured was pressed as described above, and the thickness thereof was measured. The measurement result of the thickness is as shown in FIG. The number on the horizontal axis indicates the sample number. In this comparative example, it was confirmed that the thickness of the electrode assembly did not fall within the target range in all samples. That is, it was confirmed that the overall thickness was larger than that of the sample of the example.

  It has been found that the residual air A remaining in the separator bag 90 of the positive electrode unit 80 can be discharged by using the gas discharge device 1 described above from the example and the comparative example described above.

  Although one embodiment has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention.

  In the gas discharge device 1 of the above-described embodiment, as illustrated in FIG. 4, an example in which the air G from the nozzle 11 a is sprayed only on one separator 91 side constituting the separator bag 90 has been described. Is not limited to this. For example, after blowing the air G from the nozzle 11a from one separator 91 side constituting the separator bag 90, the front and back of the positive electrode unit 80 are turned over, and from the other separator 91 side constituting the separator bag 90 from the nozzle 11a. The air G may be sprayed. Thus, the residual gas A remaining between the positive electrode plate 81 and the one separator 91, the positive electrode plate, and the other by blowing the air G from the nozzle 11a from the both separator 91 side constituting the separator bag 90. The residual gas A remaining between the separator 91 and the separator 91 can be driven out toward the opening 95. As a result, the residual gas in the separator bag 90 can be discharged more reliably.

  Moreover, in the gas exhaust apparatus 1 of the said embodiment, as shown in FIG. 3, it demonstrated and demonstrated the example in which the nozzle group 11 and the nozzle 11a are arrange | positioned only at the one separator 91 side which comprises the separator bag 90. However, the present invention is not limited to this. For example, as shown in FIG. 8, the gas discharge device 101 may be configured to include a nozzle group 11 and a nozzle 11 a that are disposed on both separators 91 and 91 side that constitute the separator bag 90. In the gas discharge device 101 having this configuration, the residual gas A1 remaining between the positive electrode plate 81 and the one separator 91 and the residual gas A2 remaining between the positive electrode plate and the other separator 91 are simultaneously opened. You can drive to 95. As a result, the residual gases A1 and A2 in the separator bag 90 can be discharged more efficiently.

  In the gas discharge devices 1 and 101 of the above embodiment, the example in which the air G from the nozzle 11a is blown to the peripheral edge portion 91a of the separator 91 has been described, but the present invention is not limited to this. For example, the nozzle 11 a in the gas discharge device 201 may be provided so as to be relatively movable with respect to at least one separator 91. For example, as shown in FIGS. 9A, 9B, and 9C, the nozzle group 11 may be movably disposed with respect to the positive electrode unit 80 disposed at a predetermined position. Good.

  In the gas discharge device 201 having such a configuration, the position P11 pressed by the air G from the nozzle 11a in the separator 91 can be moved from the peripheral edge 91a of the separator 91 toward the opening 95. As a result, the residual gas A in the separator bag 90 can be moved to the opening 95, and can be expelled from the opening 95 more reliably. Such an effect can also be enjoyed by moving the positive electrode unit 80 with respect to the nozzle group 11 (or the nozzle 11a). The gas discharge device 201 may include a transport device that transports the positive electrode unit 80.

  When the positive electrode unit 80 is transported, it may be transported in a state of being sandwiched between mesh-shaped or sheet-shaped members 70 as shown in FIG. If the positive electrode unit 80 is conveyed in such a state, the residual air A in the separator bag 90 as described above can be discharged from the opening 95 and the separator 91 can be protected.

  In the gas discharge devices 1 and 101.201 of the above-described embodiment, an example has been described in which one nozzle group 11 that injects the pressure gas to the separator 91 moves sequentially to the positions of P1, P2, P3, and P4. However, the present invention is not limited to this. For example, it may be configured to include a plurality of nozzle groups 11 respectively arranged at the positions P1, P2, P3, and P4, and the pressurized gas may be injected simultaneously from the nozzles 11a of each nozzle group 11, or P1, P2 , P3 and P4 may be used to eject the pressure gas from the nozzles 11a of the nozzle group 11 arranged.

  In the gas discharge devices 1 and 101.201 of the above-described embodiment, the example in which the injection unit that injects the pressure gas to the separator 91 is configured by the nozzle group 11 and the nozzle 11a has been described, but the present invention is limited to this. Is not to be done. For example, one nozzle 11a may be configured to inject a pressurized gas to the separator 91 by receiving the supply of compressed air directly from the tank 25. Also in this case, as shown in FIG. 2, the pressure gas may be injected while sequentially moving in the direction from P1 to P4. For example, the structure which injects press gas with respect to the separator 91 by receiving supply of compressed air directly from the tank 25 may be sufficient as the some nozzle 11a. Also in this case, the pressure gas may be ejected from the plurality of nozzles 11a at the same time, or the pressure gas in the order of the nozzles 11a disposed on the P1 side and the nozzles 11a disposed on the P2, P3, and P4 sides. May be injected.

  As shown in FIG. 1, the separator bag 90 of the positive electrode unit 80 targeted by the gas discharge devices 1, 101.201 of the above embodiment is a pair of two separators 91, and the peripheral edges of the pair of separators 91, 91. Although the example in which the portions 91a and 91a are joined to each other excluding a part of the peripheral portions 91a and 91a has been described, the present invention is not limited thereto. For example, as shown in FIG. 8, one member to be a separator is bent, and the facing portions are used as a pair of separators, and the peripheral portions of the pair of separators are joined except for the opening portion. The separator bag 90 may be formed by the above.

  DESCRIPTION OF SYMBOLS 1,101,201 ... Gas discharge apparatus, 11 ... Nozzle group, 11a ... Nozzle (injection part), 15 ... Hose connection body, 17 ... Hose, 19 ... Joint for piping, 21 ... Valve, 25 ... Tank, 27 ... Hose , 80 ... Positive electrode unit (electrode unit), 81 ... Positive electrode plate (electrode), 83 ... Positive electrode metal foil, 85 ... Positive electrode active material layer, 87 ... Tab, 90 ... Separator bag, 91 ... Separator, 91a ... Peripheral part, 93 ... welding part, 95 ... opening, A, A1, A2 ... residual gas, G ... air (pressing gas).

Claims (8)

The electrode unit includes one electrode of a positive electrode and a negative electrode, and a separator bag in which peripheral portions of the separator covering both main surfaces of the electrode are joined except for a part of the peripheral portion, and accommodates the electrode A gas discharge device for discharging residual gas remaining inside the separator bag,
When the pressing gas that presses the peripheral edge of the separator covering at least one of the main surfaces is injected from the outside opposite to the inner side, and when viewed from a direction perpendicular to the main surface, the separator A gas discharge device provided with an injection part arranged so that the above-mentioned pressurization gas may be injected toward the opening which is the above-mentioned part of which the peripheral parts are not joined. The opening is provided in one place,
A tab formed on the peripheral edge of the electrode protrudes outside the separator bag from the opening.
The gas discharge device according to claim 1. A plurality of the injection units are provided.
The gas discharge device according to claim 1 or 2. The injection directions in which the injection unit injects the pressed gas intersect each other.
The gas discharge device according to claim 3. The injection unit is arranged to be able to inject the pressed gas to both the separators covering the main surface.
The gas discharge device according to any one of claims 1 to 4. The injection unit is provided to be movable relative to the separator covering at least one main surface.
The gas discharge device according to any one of claims 1 to 5. The electrode unit includes one electrode of a positive electrode and a negative electrode, and a separator bag in which peripheral portions of the separator covering both main surfaces of the electrode are joined except for a part of the peripheral portion, and accommodates the electrode A gas discharge method for discharging residual gas remaining inside the separator bag,
When the pressing gas that presses the peripheral edge of the separator covering at least one of the main surfaces is injected from the outside opposite to the inner side, and when viewed from a direction perpendicular to the main surface, the separator By injecting the pressing gas toward the opening which is the part where the peripheral portions are not joined to each other, and pressing the residual gas inside the separator bag against the outer surface of the separator A gas discharge method that drives out to the opening. By moving the electrode unit in a state sandwiched between mesh members or sheet members, the pressing position by the pressing gas is moved from the peripheral portion toward the opening,
The gas discharge method according to claim 7.

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