JP6135469B2 - Power storage device inspection method - Google Patents

Description

  The present invention relates to a method for inspecting a power storage device.

  In a power storage module, a plurality of power storage devices arranged along a predetermined arrangement direction are constrained between end plates, and a metal member (heat dissipation) for radiating heat generated in the power storage device is stored between the power storage devices. The heat transfer member etc. which convey heat to a member and a heat radiating member) are interposed. Each power storage device contains an electrode assembly, an electrolytic solution, and the like in a metal case. An insulating film is provided between the metal case and the heat dissipating metal member in order to prevent a short circuit between the power storage devices having the heat dissipating metal member interposed therebetween. FIG. 3 shows an example between the power storage devices 100 and 100 of the power storage module, and an insulating film 102 is provided between the case 100a of the power storage device 100 and the metal member 101 for heat dissipation.

  The surface of the case of the power storage device may be scratched or dented during manufacturing or transportation. If the scratches or dents are protrusions, the insulating film in contact with the case may be broken. When the insulating film is broken, the metal case and the metal member for heat dissipation are short-circuited, so it is necessary to inspect whether there is such a protrusion. For example, in Patent Document 1, a portion corresponding to a bent portion of a current collector plate is pressed in the stacking direction of the electrode plate group in a state where the battery unit is housed in the battery case, and a short circuit inspection between the battery case and the current collector plate is performed. A method for inspecting a short circuit of a rectangular battery is disclosed. When there is a protruding foreign object in the bent part of the current collector plate, the current collector insulating tape attached to the current collector plate is pierced by the protruding foreign object by applying pressure. Since a short circuit occurs, it is disclosed that such a protruding foreign object can be detected as a short circuit defect.

JP 2008-181858 A

  Patent Document 1 discloses a short circuit inspection in a single power storage device. By performing a short circuit inspection between the case (battery case) and the current collector plate in the case, the current collector plate inside the case is disclosed. Projecting foreign matter or the like present in the bent portion of the. In the case of a power storage module composed of a plurality of power storage devices, as shown in FIG. 3, there are protrusions P, P in each case 100a, 100a of adjacent power storage devices 100, 100, and they are insulated by the protrusions P, P. If each of the films 102 and 102 is broken, the cases 100a and 100a are short-circuited via the metal member 101 for heat dissipation. Then, the potential of the case 100a changes, and the electrolytic solution in the case 100a may be decomposed due to a potential difference between the positive electrode of the electrode assembly in the case 100a and the case 100a. Therefore, in the case of the power storage module, in order to prevent a short circuit between the power storage devices 100 and 100 of the power storage module, it is important to inspect whether there is a protrusion or the like outside the case 100a of the power storage device 100.

  Therefore, in the present technical field, there is a demand for a method for inspecting a power storage device for preventing a short circuit between the power storage devices of the power storage module.

  A power storage device inspection method according to an aspect of the present invention is a power storage device inspection method for a power storage module configured by connecting a plurality of power storage devices each containing an electrode assembly and an electrolyte in a metal case. A sandwiching step of sandwiching the power storage device with the insulating member interposed between the pair of metal restraining members; and And an inspection process for performing a short circuit inspection with the case.

  In this inspection method, first, an insulating member is disposed between each surface of the power storage device (case) and the restraining member, and the power storage device is sandwiched between the pair of restraining members with the insulating member interposed. The surface where the power storage device is sandwiched is a surface in a direction in which a plurality of power storage devices are arranged in the power storage module (a surface where adjacent power storage devices face each other), and a metal member for heat dissipation with an insulating member interposed in the power storage module This is the surface on the side where is placed. The restraining member is made of metal. The insulating member is a member having the same material as the insulating member provided between the case of the power storage device and the heat dissipating metal member in the power storage module, or a member of the same level, or a member of the same level. The insulating member itself used may be used. In this inspection method, a short circuit inspection is performed between the restraining member and the case of the power storage device in a state where the power storage device is restrained between the pair of restraining members. When a short circuit is not detected in this short circuit inspection, it is presumed that the case and the restraining member are insulated from each other by an insulating member, and the case does not have a projection that breaks the insulating member. On the other hand, when a short circuit is detected in the short circuit inspection, the case and the restraining member are not insulated by the insulating member, and it is estimated that the case has a protrusion that breaks the insulating member. In this case, if this power storage device is used, there is a possibility that a short circuit occurs between adjacent power storage devices via a heat dissipating metal member. Therefore, the power storage device that causes this insulation failure is not used for the power storage module. Thus, according to this inspection method, the case is formed by performing a short circuit inspection between the case and the restraining member in a state where the insulating member is interposed on both sides of the power storage device and restrained by the pair of metal restraining members. Since it is possible to estimate (determine) whether or not there is a protrusion that breaks the insulating member (and thus whether or not the power storage device is defective in insulation), a short circuit between the power storage devices of the power storage module can be prevented. .

  In one form of the method for testing a power storage device, the short circuit test is a resistance test. By performing a resistance test as a short circuit test, if the detected resistance value is small, the resistance between the case and the restraining member is small, so the case and the restraining member are not insulated by the insulating member, and the case It can be inferred that there are protrusions.

  In one form of the method for inspecting a power storage device, an insulating film is interposed between the case of the power storage device and a metal member for heat dissipation in the power storage module, and the insulating member is made of the same material as the insulating film, and the insulating film And the same thickness. As described above, since the short circuit inspection is performed using the insulating material having the same thickness and the same material as the insulating film actually used in the power storage module, it is possible to perform the inspection according to the actual situation in the power storage module.

  In an inspection method for a power storage device according to one aspect, the inspection step is performed in a step of charging the power storage device before being assembled to the power storage module. Thus, since the short circuit inspection is performed using the charging process of the power storage device, it is not necessary to restrain the power storage device with a restraining member exclusively for the short circuit inspection, and the inspection cost and the inspection man-hour can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the short circuit between the electrical storage apparatuses of an electrical storage module can be prevented.

It is a top view which shows typically the electrical storage module which consists of an electrical storage apparatus which concerns on this Embodiment. It is a side view which shows typically the structure at the time of the test | inspection of the electrical storage apparatus which concerns on this Embodiment. It is a side view which shows typically the case where a short circuit generate | occur | produced between the electrical storage apparatuses which an electrical storage module adjoins.

  Hereinafter, an embodiment of an inspection method for a power storage device according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected about the element which is the same or it corresponds in each figure, and the overlapping description is abbreviate | omitted.

  The method for inspecting a power storage device according to the present embodiment is a charging / discharging process for the power storage device that is performed after the power storage device is manufactured (before being assembled to the power storage module) (at least a step of charging the power storage device, (It may not be performed). In the charge / discharge process, the power storage device is sandwiched between a pair of restraining plates for the purpose of uniformizing the reaction between the positive electrode and the negative electrode (and also for the purpose of suppressing expansion due to gas generated in the power storage device). This is a step of charging and discharging while applying pressure. A power storage device that is determined to be defective by the inspection is not used for a power storage module.

  With reference to FIG.1 and FIG.2, the test | inspection method of the electrical storage apparatus 1 which concerns on this Embodiment is demonstrated. FIG. 1 is a plan view schematically showing a power storage module including the power storage device 1. FIG. 2 is a side view schematically showing the configuration of the power storage device 1 during inspection.

  Before describing the inspection method, the configuration of the power storage module M will be described with reference to FIG. The power storage module M is configured in a state in which a plurality of power storage devices 1 are arranged via a heat radiating plate 2 and the arrayed body is constrained between a pair of end plates 3 and 3 arranged on both end faces in the arrangement direction. ing. In the present embodiment, the heat radiating plate 2 corresponds to a metal member for heat dissipation described in the claims. In addition, the structure of the electrical storage module M demonstrated here is an example, and the electrical storage module of other various structures is applicable.

  The power storage device 1 is a rectangular power storage device. The plurality of power storage devices 1 are arranged in a state in which the end plates 3 are arranged in a predetermined arrangement direction (the arrangement direction in which the widest surfaces of the rectangular power storage devices are in contact with each other and the positive electrode and the negative electrode are stacked). By being sandwiched between the three, a restraining pressure is applied and restrained. Below, the structure of the electrical storage apparatus 1 (especially lithium ion secondary battery) is demonstrated. Note that the configuration of the power storage device 1 described below is an example, and power storage devices having other various configurations can be applied.

  The power storage device 1 mainly includes a case 1a, an electrolytic solution, and an electrode assembly. The case 1a is a case that accommodates the electrolytic solution and the electrode assembly, and has a square shape. The case 1a is formed of a metal such as aluminum or stainless steel. The electrolytic solution is accommodated in the case 1a and impregnated in the electrode assembly. The electrolytic solution is, for example, an organic solvent-based or non-aqueous electrolytic solution.

  The electrode assembly includes a positive electrode, a negative electrode, and a separator that insulates the positive electrode from the negative electrode. The electrode assembly is configured by laminating a plurality of sheet-like positive electrodes, a plurality of negative electrodes, and a plurality of sheet-like (or bag-like) separators. The electrode assembly is accommodated in the case 1a and filled with the electrolyte in the case 1a.

  The positive electrode includes a metal foil and a positive electrode active material layer formed on at least one surface of the metal foil. The positive electrode has a tab on which the positive electrode active material layer is not formed at the end of the metal foil. The tab extends to the upper edge of the positive electrode and is connected to the positive electrode terminal 1b via a conductive member. The metal foil is, for example, an aluminum foil or an aluminum alloy foil. The positive electrode active material layer includes a positive electrode active material and a binder. The positive electrode active material layer may contain a conductive additive. The positive electrode active material is, for example, a composite oxide, metallic lithium, or sulfur. The composite oxide includes at least one of manganese, nickel, cobalt, and aluminum and lithium. The binder is, for example, a thermoplastic resin such as polyamideimide or polyimide, or a polymer resin having an imide bond in the main chain. Examples of the conductive auxiliary agent include carbon black, graphite, acetylene black, and ketjen black (registered trademark).

  The negative electrode includes a metal foil and a negative electrode active material layer formed on at least one surface of the metal foil. The negative electrode has a tab on which the negative electrode active material layer is not formed at the end of the metal foil. The tab extends to the upper edge of the negative electrode and is connected to the negative electrode terminal 1c via a conductive member. The metal foil is, for example, a copper foil or a copper alloy foil. The negative electrode active material layer includes a negative electrode active material and a binder. The negative electrode active material layer may contain a conductive additive. Examples of the negative electrode active material include graphite, highly oriented graphite, carbon such as mesocarbon microbeads, hard carbon, and soft carbon, alkali metals such as lithium and sodium, metal compounds, and SiOx (0.5 ≦ x ≦ 1.5). ) And the like, and boron-added carbon. As the binder and the conductive auxiliary, the same binder and conductive auxiliary as shown in the positive electrode can be applied.

  The separator separates the positive electrode and the negative electrode and allows lithium ions to pass while preventing a short circuit of current due to contact between the two electrodes. The separator is, for example, a porous film made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP), a woven fabric or a nonwoven fabric made of polypropylene, polyethylene terephthalate (PET), methylcellulose or the like.

  When the plurality of power storage devices 1 are arranged along the above-described arrangement direction, the positions of the positive electrode terminal 1 b and the negative electrode terminal 1 c are alternately arranged between the adjacent power storage devices 1 and 1. Then, the positive electrode terminal 1b and the negative electrode terminal 1c are connected by the connecting member 1d between the adjacent power storage devices 1 and 1, and the plurality of power storage devices 1 are electrically connected in series.

  Insulating films 4 and 4 are attached to the respective surfaces on both sides in the arrangement direction in the case 1 a of the power storage device 1. Therefore, the insulating film 4 is interposed between the case 1a and the heat radiating plate 2 (which may be the end plate 3). The insulating film 4 is an insulating member for preventing a short circuit between the adjacent power storage devices 1 and 1. As the insulating film 4, a known film used in a conventional power storage module can be applied. The insulating film 4 has a rectangular shape that can sufficiently cover the surface in the arrangement direction of the case 1 a of the power storage device 1. In order not to reduce the heat transfer from the power storage device 1 to the heat sink 2, it is preferable that the insulating film 4 is thin. In the present embodiment, the insulating film 4 corresponds to the insulating film described in the claims. In addition, since the some electrical storage apparatus 1 is restrained between the end plates 5 and 5, without sticking the insulating film 4 on the surface of the both sides of the case 1a, case 1a and the heat sink 2 (or end plate 5) It may be only in the state of being sandwiched between.

  The heat radiating plate 2 is a member for radiating heat generated in the power storage device 1. The heat radiating plate 2 has a plate shape having a predetermined thickness, and the surface in contact with the insulating film 4 is a surface that is sufficiently larger than the surface in the arrangement direction of the power storage device 1. The heat sink 2 is formed of a metal such as aluminum or stainless steel. In addition, although the member for radiating the heat | fever which generate | occur | produced in the electrical storage apparatus 1 is made into the heat sink 2, you may radiate | emit with other structures. For example, a heat transfer plate is interposed between the power storage devices 1 and 1, and heat is transferred from the heat transfer plate to a heat radiating member, a cooling member, or the like to radiate heat.

  The end plate 3 is disposed at both ends of the plurality of power storage devices 1 arranged along the arrangement direction, and is a member for restraining the plurality of arranged power storage devices 1 by applying a restraining pressure from both sides. It is. End plate 3 has a plate shape, and the surface in contact with insulating film 4 is a surface that is sufficiently larger than the surface of power storage device 1 in the arrangement direction. The end plate 3 has a thickness sufficient to apply a restraining pressure. The end plate 3 has a plurality of through holes (not shown) having a diameter into which the connecting member 3a can be inserted. The positions of the through holes are, for example, around the corners of the four corners of the end plate 3. The connecting member 3a is a rod-shaped member, and male threads are cut at both ends. In a state where a plurality of power storage devices 1 are sandwiched between the end plates 3 and 3 with the heat dissipation plate 2 interposed therebetween, the connecting members 3a are passed through the through holes of the end plates 3 and 3 on both sides, respectively. Nuts 3b and 3b are respectively screwed into male screws at both ends of 3a. As a result, a restraining pressure is applied to the plurality of power storage devices 1 between the end plates 3 and 3 so as to be restrained.

  Now, an inspection method for the power storage device 1 will be described with reference to FIG. The power storage device 1 is inspected before or after the power storage device 1 is charged or discharged in the charge / discharge process. In this charging / discharging process, usually, the power storage device 1 is sandwiched between the pair of restraining plates 10, 10, and charging / discharging is performed while applying restraining pressure to the power storage device 1 from the restraining plates 10, 10. The direction in which this sandwiching and restraining pressure is applied is the direction in which the positive electrode and the negative electrode of the power storage device 1 are laminated.

  The restraint plate 10 is plate-shaped and has a sufficient thickness that allows the restraint pressure to be applied. The restraining plate 10 is made of metal. The surface of the restraining plate 10 to which the restraining pressure is applied has a size and shape that is sufficiently wider than the surface where the rectangular power storage device 1 is sandwiched. The constraining plate 10 has a plurality of through holes into which the bolts 10a can be inserted. The positions of the through holes are, for example, around the corners of the four corners of the restraint plate 10. In particular, a female screw is cut in the through hole of the restraining plate 10 on one side. Each bolt 10 a is inserted into each through hole of the restraining plates 10, 10 sandwiching the power storage device 1, and the male screw is screwed into the female screw of the through hole of the restraining plate 10 on one side. Thereby, the restraint plates 10 and 10 are connected by the plurality of bolts 10a, and restraint pressure is applied between the restraint plates 10 and 10 by the fastening force of the bolts 10a.

  In order to inspect the power storage device 1, unlike the conventional charge / discharge process, insulating films 11 and 11 are interposed between the power storage device 1 and the restraining plates 10 and 10. Then, with the insulating film 11 interposed between the power storage device 1 and the restraint plate 10, the power storage device 1 is restrained between the restraint plates 10 and 10. In this state, a resistance test is performed between the restraint plate 10 on one side and the case 1a of the power storage device 1 by the resistance test device 12, and a resistance is detected between the restraint plate 10 on the other side and the case 1a of the power storage device 1. A resistance test is performed by the test device 12. In the present embodiment, the restraint plate 10 corresponds to the restraint member described in the claims, the insulating film 11 corresponds to the insulation member described in the claims, and the resistance inspection device 12 falls in the claims. It is an apparatus for performing the short circuit inspection described.

  The insulating film 11 is a member for insulating between the case 1 a and the restraining plate 10. The insulating film 11 has a size and shape that is sufficiently wider than the surface between which the rectangular power storage device 1 is sandwiched, for example, the same size and shape as the surface of the restraining plate 10. The insulating film 11 has the same thickness as the insulating film 4 provided on both sides of the power storage device 1 in the power storage module M, and is an insulating film formed of the same material (same material). Note that the insulating film 11 is not dedicated to inspection, and the insulating film 4 used in the power storage module M attached to the case 1a of the power storage device 1 may be used as it is.

  The resistance inspection device 12 is a device that measures a resistance value between the metal restraint plate 10 and the metal case 1a. The resistance test apparatus 12 is, for example, a known tester that measures a resistance value. When the restraint plate 10 and the case 1a are insulated by the insulating film 11, the resistance value measured by the resistance inspection device 12 becomes a very large value. On the other hand, when the insulating film 11 is damaged and short-circuited between the restraint plate 10 and the case 1a, the resistance value measured by the resistance inspection device 12 is a small value. Since the difference between the resistance values is very large, the resistance value between them is set in advance as a threshold value, and if the resistance value measured by the resistance inspection device 12 is smaller than the threshold value, it is determined that the short circuit is present. Good.

  The effect | action of the short circuit test | inspection with respect to the electrical storage apparatus 1 by said structure is demonstrated. First, in the sandwiching step, the power storage device 1 is sandwiched between the pair of restraint plates 10 and 10 with the insulating film 11 interposed between the power storage device 1 and the restraint plate 10. Further, in the sandwiching step, the restraint plates 10 and 10 are connected by a plurality of bolts 10 a, and restraint pressure is applied from the restraint plates 10 and 10 to the power storage device 1. In addition, also when charging / discharging in a charging / discharging process, even if it charges / discharges in the state which interposed the insulating film 11 between the electrical storage apparatus 1 and the restraint board 10, it is satisfactory.

  Next, in the inspection step, the resistance testing device 12 on one side is connected between the case 1a of the power storage device 1 and the restraining plate 10 on one side, and the case 1a of the power storage device 1 and the restraining plate 10 on the other side are connected. The resistance inspection device 12 on the other side is connected between the two. Further, in the inspection process, the resistance value in the resistance inspection device 12 on one side is measured, and the resistance value in the resistance inspection device 12 on the other side is measured. And it is determined whether each resistance value measured with each resistance test | inspection apparatus 12 is smaller than a threshold value.

  For example, as shown in FIG. 2, the case 1 a has protrusions P due to scratches, dents, etc., and the power storage device 1 is applied with a restraining pressure between the restraining plates 10 and 10, and the insulating film 11 is formed by the protrusions P. When it is torn, the metal case 1a is short-circuited (conducted) between the metal case 1a and the metal restraint plate 10 on the side where the protrusion P is located via the protrusion P (metal). Therefore, it is determined that the resistance value measured by the resistance inspection device 12 on the side where the protrusion P is present is smaller than the threshold value and short-circuited (insulation failure). In this case, the power storage device 1 is not used in a process that is assembled as a power storage module M in a subsequent process, and is handled as a defective product. In addition, the power storage device 1 treated as a defective product is determined to be a short circuit (insulation failure) on at least one side in the short circuit inspection on both sides.

  When the insulating film 11 is functioning normally even when the case 1a has no protrusions P and the power storage device 1 is applied with a restraining pressure between the restraining plates 10 and 10, the metal case 1a and the metal restraint The board 10 is insulated. Therefore, the resistance value measured by the resistance inspection apparatus 12 becomes larger than the threshold value, and it is determined that the short circuit is not short (insulation normal). When it is determined that both are not short-circuited in the short-circuit inspection on both sides, the power storage device 1 is used in a process that is assembled as a power storage module M in a subsequent process.

  According to this inspection method for the power storage device 1, a short circuit inspection between the case 1 a and the restraint plate 10 in a state where the insulating film 11 is interposed on both sides of the power storage device 1 and restrained between the metal restraint plates 10 and 10. By performing (especially resistance inspection), it is possible to determine whether or not the metal case 1a and the metal restraint plate 10 are short-circuited, and the projection P that breaks the insulating film 11 in the case 1a. It can be estimated (determined) whether or not there is (as a result, whether or not the power storage device 1 has insulation failure). As a result, the power storage device 1 that causes insulation failure is not used in a subsequent process, and a short circuit through the heat dissipation plate 2 between the power storage devices 1 and 1 connected in series in the power storage module M can be prevented.

  In the inspection method for the power storage device 1, since the short circuit inspection is performed using the charge / discharge process, it is not necessary to restrain the power storage device 1 with a restraining member exclusively for the short circuit inspection, and the inspection cost and the number of inspection processes can be reduced.

  As mentioned above, although embodiment which concerns on this invention was described, this invention is implemented in various forms, without being limited to the said embodiment.

  For example, in this embodiment, the power storage device charging / discharging process is used to perform a short circuit inspection of the power storage device. However, the short circuit inspection is performed in another process (for example, an inspection process for the power storage device other than the short circuit inspection). It may be performed or a short circuit inspection alone may be performed.

  In this embodiment, the resistance test is performed to measure the resistance value as the short circuit test. However, another short circuit test may be performed. For example, a current is supplied from one side between the case and the restraint plate. Then, the current value is measured on the other side, the measured current value is determined, and a short circuit inspection is performed.

  DESCRIPTION OF SYMBOLS 1 ... Power storage device, 1a ... Case, 2 ... Heat sink, 3 ... End plate, 4 ... Insulating film, 10 ... Restraint plate, 10a ... Bolt, 11 ... Insulating film, 12 ... Resistance test apparatus.

Claims (3)

A method for inspecting a power storage device of a power storage module configured by connecting a plurality of power storage devices each containing an electrode assembly and an electrolyte in a metal case,
A sandwiching step of sandwiching the power storage device with an insulating member interposed between a pair of metal restraining members;
An inspection step of performing a short circuit inspection between the restraining member and the case in a state of being restrained by a pair of the restraining members with the insulating member interposed from both sides of the power storage device;
Only including,
In the power storage module, an insulating film is interposed between the case of the power storage device and a metal member for heat dissipation,
The method for testing a power storage device, wherein the insulating member is made of the same material as the insulating film and has the same thickness as the insulating film .   The power storage device inspection method according to claim 1, wherein the short circuit inspection is a resistance inspection. The inspection process, the is performed in the process of charging the power storage device before it is assembled to the power storage module, the inspection method of a power storage device according to claim 1 or 2.

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