JP2006134599A - Battery module and inspection method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery module and its inspection method for sorting the battery module in which generated welding dust can simply, easily, and rapidly be selected, and to provide a battery module for preventing the short-circuiting of a unit cell by the welding dust. <P>SOLUTION: The method for inspecting the battery module inspects short-circuiting by the welding dust A in the battery module 50 in which a plurality of unit cells 10 are electrically connected to a connection fixture 20 between batteries by welding. In the inspection method of the battery module, a magnetic metal attracted by magnetic action is used for the connection fixture 20, and a magnetic field is made to act on the battery module 50, thus moving the welding dust A generated when welding the connection fixture 20 by a magnetic attraction force, detecting a voltage of the unit cells 10, and detecting the short-circuiting of the welding dust A. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention is to inspect the short circuit caused by the welding dust of the battery module in which the connecting metal is disposed on the facing surface of the unit cell, the connecting metal is welded to the facing unit cell, and the unit cell is electrically connected. And a battery module capable of efficiently performing a short circuit inspection by welding dust or preventing a short circuit by welding dust.
In particular, the present invention relates to a battery module inspection method for supplying power to a motor for running a vehicle, such as a hybrid car, an electric vehicle, or a fuel cell vehicle, and a battery module optimal for this application. However, the present invention relates to battery modules in general for applications that require a large output and for applications that require space saving of a plurality of unit cell connection portions, even if the application is other than an electric vehicle.

In the battery module that drives the motor of the electric vehicle, it is important to reduce the electrical resistance of the connecting portion. This is because the battery module used for this type of application has a high output voltage by connecting a number of unit cells in series. That is, since a large number of unit cells are connected in series, if the electrical resistance of the connecting portion is large, the total electrical resistance becomes extremely large. A battery module that reduces the electrical resistance of the connecting portion has been developed (see Patent Document 1).
JP 2003-223878 A

  The battery module described in this publication has unit cells 10 connected in series with the connection structure shown in FIGS. 1 and 2. In the battery modules shown in these drawings, the end surfaces of the unit cells 10 are connected in series via the connection fitting 20. The connection fitting 20 is disposed between the end faces of the unit cells 10 disposed close to each other, and is electrically connected to the electrodes of the unit cells 10 facing each other. The battery module of FIG. 1 is electrically connected by welding the central portion of the connection fitting 20 to the sealing plate 12 and the outer peripheral portion to the outer can 11. In the battery module of FIG. 2, a cylindrical portion 28 into which an end portion of the outer can 11 of the unit cell 10 is inserted is provided on the outer periphery of the connection fitting 20, and a plate portion 27 is provided inside the cylindrical portion 28. The connection fitting 20 connects the unit cells 10 in series by welding the cylindrical portion 28 to the outer can 11 and the plate portion 27 to the sealing plate 12.

  The battery modules shown in these figures are connected in a low resistance state via a connection fitting. However, when welding the connection fitting, a part of the molten portion of the connection fitting may be scattered as a welding dust. Since the welding dust is conductive, it may move between the sealing plate 12 of the unit cell 10 and the outer can 11 and short-circuit the unit cell 10 as shown in FIG. For this reason, the battery module in which the welding dust A is generated cannot be used as a normal product because the unit cell 10 may be short-circuited by the welding dust A. For this reason, the battery module in which welding dust has occurred needs to be selected as a defective product.

  However, it is not easy to select a battery module that has weld dust when welding the connection fittings. This is because the welding dust does not necessarily move to a position where the sealing plate and the outer can are short-circuited, and since the short current of the welding dust is extremely small, the voltage of each unit cell is detected and the welding dust is short-circuited. This is because it is difficult to detect. If the short-circuit current of the welding dust is large, when this short-circuits the unit cell, the voltage drop of the short-circuited unit cell increases. For this reason, it is possible to detect the voltage drop of the unit cell and detect the occurrence of welding dust. However, since the short-circuit current of the welding dust is actually small, even if this temporarily short-circuits the unit cell, the voltage drop of the unit cell is small, and in order for the voltage drop to become noticeable, it has a certain aging period. There is a need. This makes it difficult to select battery modules with weld dust.

The present invention has been developed for the purpose of solving the conventional drawbacks. An important object of the present invention is to provide a battery module that can easily and quickly sort out battery modules in which welding dust has occurred, and an inspection method thereof.
Another object of the present invention is to provide a battery module that can prevent a short circuit of a unit cell due to welding dust.

The inspection method for a battery module according to the present invention is a method for inspecting a short circuit caused by a welding dust A of a battery module 50 in which a plurality of unit cells 10 are welded to a connection fitting 20 between batteries and electrically connected.
The battery module inspection method according to claim 1 of the present invention uses a magnetic metal attracted by a magnetic action for the connection fitting 20 and welds the connection fitting 20 by applying a magnetic field to the battery module 50. The welding dust A that is sometimes generated is moved by the magnetic attraction force, and the voltage of the unit cell 10 is detected to detect a short of the welding dust A.

  The battery module inspection method according to claim 2 of the present invention detects the voltage of the unit cell 10 by forcibly vibrating the battery module 50 and moving the welding dust A generated when welding the connection fitting 20. A short of welding dust A is detected. In this inspection method, the battery module 50 can be forced to vibrate by moving it onto the plurality of rollers 41, or can be forced to vibrate by dropping the battery module 50 onto the inclined surface 43.

  The battery module inspection method according to claim 5 of the present invention occurs when the battery module 50 is ultrasonically vibrated or ultrasonic vibration is applied between the unit cells 10 and the connection fitting 20 is welded by ultrasonic vibration. The welding dust A is moved, the voltage of the unit cell 10 is detected, and a short of the welding dust A is detected.

  In the battery module inspection method according to claim 6 of the present invention, air is forcibly blown between the unit cells 10 of the battery module 50, and the welding dust A generated when the connection fitting 20 is welded is moved by this air flow. Then, the voltage of the unit cell 10 is detected to detect a short of the welding dust A.

In the battery module of the present invention, a connection fitting 20 is disposed between a plurality of unit cells 10, and the connection fitting 20 is welded and electrically connected to the unit cell 10.
The battery module according to claim 7 of the present invention is provided with the insulating low friction layer 17 that makes the movement of the welding dust A smooth on the surface of the unit cell 10 facing the connection fitting 20.

  In the battery module according to claim 8 of the present invention, the insulating adhesive layer 18 is provided on the opposing surface of the unit cells 10 connected by the connection fitting 20 to prevent the movement by attaching the welding dust A.

  The battery module according to claim 9 of the present invention is a facing surface of the unit cells 10 connected by the connection fitting 20, and the boundary between the sealing plate 12 and the outer can 11 is covered with an insulating coating film 19 to weld dust. A short circuit is prevented.

  In the battery module of claim 10 of the present invention, the connection fitting 20 is disposed inside the cylindrical portion 28 and the cylindrical portion 28 where the end of the outer can 11 of the unit cell 10 is inserted and electrically connected, It has the plate part 27 currently welded to the sealing plate 12 of the unit cell 10. Further, the battery module is provided with a blower opening 29 for forcibly blowing the air moving the welding dust A between the unit cells 10 in the cylindrical portion 28, and forcibly blows air between the unit cells 10 from the blower opening 29. The welding dust A can be moved between the unit cells 10.

  The battery module according to an eleventh aspect of the present invention includes an insulating cap 30 on the end face of the unit cell 10 to prevent a short circuit of the unit cell 10. The insulating cap 30 includes a cylindrical portion 31 into which an end of the outer can 11 of the unit cell 10 is inserted, and an insulating ring portion that is inside the cylindrical portion 31 and insulates the connection fitting 20 and the outer can 11 from each other. 32. The battery module is provided with a blower opening 39 for forcibly blowing the air moving the welding dust A between the unit cells 10 in the cylindrical portion 31, and forcibly blows air between the unit cells 10 from the blower opening 39, The welding dust A can be moved between the unit cells 10.

  The battery module inspection method of the present invention has an advantage that battery modules in which welding dust has occurred can be easily and easily selected. This is because the battery module inspection method of the present invention moves the welding dust generated when welding the connection fitting, and detects the short-circuit of the welding dust by detecting the voltage of the unit cell. The welding dust that occurs when welding connection fittings is not always in the short position. In the battery module in which the weld dust is not in the short position, if the weld dust moves to the short position during use, the performance of the unit cell is remarkably deteriorated and the life of the unit cell is remarkably shortened. For this reason, the battery module in which welding dust has occurred needs to be selected as a defective module even if the welding dust is not in the short position. According to the battery module inspection method of the present invention, the welding dust is moved to the short position, and the battery module that causes the welding dust to short-circuit the unit cell is selected as a defective product. Therefore, even a battery module in which the welding dust is not in the short position can be identified as a defective module by quickly moving the welding dust to the short position.

  Furthermore, the battery modules according to claims 7, 10 and 11 of the present invention have a feature that the welding dust generated when welding the connecting fitting is quickly moved to the short position and can be identified as a defective module. In the battery module according to the seventh aspect, since the insulating low friction layer is provided on the surface facing the connection fitting of the unit cell, the welding dust can be smoothly moved and can be quickly moved to the short position. The battery module according to claim 10 is provided with a ventilation opening for forcibly blowing the air that moves the welding dust between the cells in the cylindrical portion of the connection fitting. The welding dust can be quickly moved to the short position. In the battery module according to the eleventh aspect, since the blower opening for forcibly blowing the air that moves the welding dust between the unit cells is provided in the cylinder portion of the insulating cap that prevents the short circuit of the unit cell, Forced air can be blown between the batteries to quickly move the welding dust to the short position.

  Furthermore, the battery modules according to claims 8 and 9 of the present invention have an advantage that it is possible to effectively prevent short-circuiting of the unit cells due to welding dust generated when welding the connection fitting. In the battery module of claim 8, since the insulating adhesive layer is provided on the opposing surface of the unit cells connected by the connection fitting, the generated welding dust is adhered to the insulating adhesive layer to prevent the movement of the welding dust. Effectively prevent short-circuiting of unit cells. Moreover, since the battery module of Claim 9 has coat | covered the boundary of a sealing board and an exterior can with the insulating coating film, the short circuit of the welding dust in this part can be prevented effectively.

  Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below exemplify a battery module and an inspection method for the battery module for embodying the technical idea of the present invention, and the present invention does not specify the battery module and the inspection method below. .

  Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  The battery module 50 shown in FIG. 4 has a plurality of unit cells 10 connected in series. Further, the battery module 50 connects the unit cells 10 linearly. The battery module 50 having this structure is mainly used as a power source for driving a motor that drives the vehicle, such as a hybrid car, an electric car, or a fuel cell car. However, the battery module of the present invention can be used for applications other than electric vehicles and requiring high output. In the illustrated battery module 50, the unit cell 10 is a cylindrical battery. However, the battery module can also be connected in a straight line in series with a unit cell as a square battery.

  As shown in FIG. 5, the battery modules 50 are housed in the case 70 in parallel to the same plane. The battery modules 50 arranged side by side are connected in series to increase the output voltage. Both ends of the battery module 50 are fixed to the case 70. In this battery module 50, terminals 60 connected to the case 70 are fixed so as to protrude from the battery end surfaces at both ends. In the illustrated battery module 50, a terminal 60 is fixed perpendicularly to the end face of the battery. The terminal 60 is fixed by screwing to a bus bar 72 inserted into a fixed position of the lower case 71. The bus bar 72 connects adjacent battery modules to each other and electrically connects the battery modules in series. The bus bar 72 and the terminal 60 are sandwiched between a lower case 71 and an upper case (not shown) and fixed in place.

  As the unit cell 10, any rechargeable battery such as a nickel-hydrogen battery, a lithium ion secondary battery, or a nickel-cadmium battery can be used. However, nickel-hydrogen batteries are suitable for secondary batteries used in battery modules for electric vehicles. This is because the output with respect to the volume and weight is large, and it has the performance of excellent large current characteristics and high safety.

  In the unit cell 10 shown in the sectional views of FIGS. 6 and 7, the opening of the outer can 11 is hermetically sealed with a sealing plate 12. The outer can 11 and the sealing plate 12 are metal plates such as iron, iron alloy, aluminum, and aluminum alloy. The outer can 11 is manufactured by press-molding a metal plate into a cylindrical shape with the bottom closed. The sealing plate 12 is provided with a convex electrode 13 in the center. An electrode (not shown) is built in the outer can 11. Furthermore, the electrolyte solution is also filled. The outer can 11 has a sealing plate 12 hermetically fixed by caulking the end of the opening. The sealing plate 12 is sandwiched between the caulked portions of the outer can 11 via the gasket 14 and is hermetically fixed. The gasket 14 is a rubber-like elastic body made of an insulating material. The gasket 14 insulates the sealing plate 12 and the outer can 11, and airtightly closes the gap between the sealing plate 12 and the outer can 11. In the unit cell 10 having this structure, a groove portion 15 is provided along the periphery at the end portion where the sealing plate 12 is provided in order to crimp the sealing plate 12 and sandwich it. Further, crimping ridges 16 are provided on the periphery of the sealing plate 12. This unit cell 10 has a sealing plate 12 as a first electrode and an outer can 11 as a second electrode. The nickel-hydrogen battery uses the first electrode formed of the sealing plate 12 as a positive electrode and the second electrode formed of the outer can 11 as a negative electrode. However, the unit cell may have the first electrode as a negative electrode and the second electrode as a positive electrode.

  The battery module 50 shown in FIGS. 4 to 7 includes a plurality of unit cells 10 connected in a straight line and connected in series. In the battery module 50, the connection fitting 20 that electrically connects the unit cells 10 is disposed between the opposing end surfaces of the unit cells 10 that are linearly connected. Further, in the battery module 50, the insulating cap 30 is disposed between the outer peripheral edge of the battery end face and the connection fitting 20.

  The connection fitting 20 is manufactured by press-molding a magnetic metal attracted by a magnetic action. The connection fitting 20 is provided with metal plating layers on both sides of a base metal plate made of an iron plate or an iron alloy. The metal plating layer is composed of a conductive plating layer having excellent electrical conductivity and a small electrical resistance, and a resistance plating layer suitable for welding laminated on the surface of the conductive plating layer. The conductive plating layer is copper, silver, or an alloy thereof, and is a plating layer having a lower electrical resistance than the base metal plate and the resistance plating layer. The resistance plating layer is nickel, chrome, or an alloy thereof, and is a plating layer having an electric resistance higher than that of the conductive plating layer. The connection fitting 20 easily generates heat in the resistance plating layer and is quickly welded to the battery end face. Further, the electric resistance is small due to the conductive plating layer, and the unit cells 10 can be connected in series in a low resistance state.

  The connection fitting 20 is welded and connected to the battery end face of the adjacent unit cell 10 disposed to face the unit cell 10 in series. 8 and 9 is formed by forming a metal plate into a ring shape having a center hole 21. The connecting fitting 20 in FIG. 8 is welded to the sealing plate 12 of the unit cell 10 inside the cylindrical unit 28 that is inserted into the end of the outer can 11 of the unit cell 10 and electrically connected. The plate portion 27 is provided. The cylindrical portion 28 is provided with a welding projection 22 that protrudes from the inner surface of the outer can 11 that is the second electrode. The plate portion 27 is provided with a plurality of weld projections 22 that are welded to the sealing plate 12 on the battery end surface, which is the first electrode, protruding from the lower surface in the drawing. The connection fitting 20 of FIG. 9 is provided with a plurality of welding projections 22 that protrude from both sides and are welded to the battery end face. The welding projections 22 projecting on both surfaces are welded to the first electrode and the second electrode on the opposite end surfaces of the battery, and connect the adjacent unit cells 10 in series.

  The connection fitting 20 is provided with a center hole 21, and the convex electrode 13 is disposed here. The connection fitting can also be shaped to project the portion that guides the convex electrode without opening the center hole. The connection fitting 20 has an outer shape larger than the inner shape of the crimping ridge 16 provided on the battery end face. 6 and 7 has an outer shape substantially equal to the outer shape of the unit cell 10.

  8 and 9 is formed by press-molding a metal plate into a shape having a step between an inner peripheral portion 23 and an outer peripheral portion 24. However, in the connection fitting 20 of FIG. 8, the plate portion 27 is press-molded into a stepped shape. The inner peripheral portion 23 is disposed at a position approaching the surface of the sealing plate 12, and the outer peripheral portion 24 is disposed at a position approaching the bottom surface of the outer can 11 on the surface of the insulating cap 30. The connection fitting 20 of FIG. 9 is provided with a plurality of welding convex portions 22 on the inner peripheral portion 23 and the outer peripheral portion 24 for welding. The welding convex portion 22 of the inner peripheral portion 23 protrudes in the direction of the sealing plate 12 and is welded to the sealing plate 12. The welding convex portion 22 of the outer peripheral portion 24 protrudes toward the bottom surface of the outer can 11 and is welded to the outer peripheral portion of the bottom surface of the outer can 11. The connection fitting 20 in FIG. 8 welds the welding convex portion 22 of the inner peripheral portion 23 of the plate portion 27 and the welding convex portion 22 of the cylindrical portion 28 to opposite batteries, and the connection fitting 20 in FIG. The welding convex part 22 of the part 23 and the outer peripheral part 24 is welded to the opposing unit cell 10, and the unit cell 10 is connected in series.

  As shown in FIGS. 6 and 7, the insulating cap 30 is formed by molding an insulating material such as plastic or synthetic rubber into a ring shape. Since the unit cell 10 uses the sealing plate 12 as the first electrode and the outer can 11 as the second electrode, the caulking ridge 16 in which the connection fitting 20 connected to the sealing plate 12 is a part of the outer can 11. Short circuit when touching. In order to insulate the sealing plate 12 and the outer can 11 from each other, an insulating cap 30 is disposed between the connection fitting 20 connected to the sealing plate 12 and the crimping ridge 16 of the outer can 11 to insulate it. Yes. The insulating cap 30 shown in the figure includes an insulating ring portion 32 that insulates the connection fitting 20 connected to the sealing plate 12 and the caulking ridge 16 that is a part of the outer can 11, and an outer periphery of the insulating ring portion 32. And a cylindrical portion 31 which is molded so as to be connected to the cylinder. Since the plastic insulating cap 30 can integrally form the whole of the cylindrical portion 31 and the insulating ring portion 32, it is not necessary to separately manufacture and connect the insulating ring portion 32 and the cylindrical portion 31.

  The insulating cap 30 is disposed between the adjacent unit cells 10. The insulating cap 30 is provided with a through-hole 33 for welding both surfaces of the connection fitting 20 to opposite battery end surfaces. The through hole 33 is opened in the insulating ring portion 32. Furthermore, the insulating cap 30 shown in the drawing places the connecting metal fitting 20 at a predetermined position by bringing the inner peripheral surface of the through hole 33 of the insulating ring portion 32 into contact with the outer peripheral surface of the stepped portion 25 of the connecting metal fitting 20. Further, the insulating cap 30 of FIGS. 6 and 7 is provided with a ring ridge 35 covering the inner surface of the crimping ridge 16 integrally formed on the inner peripheral edge of the insulating ring portion 32. The ring ridge 35 is shaped to be fitted inside the caulking ridge 16. The insulating cap 30 is disposed at a fixed position by fitting the ring ridge 35 inside the crimping ridge 16, and insulates the connection fitting 20 and the crimping ridge 16.

  The cylinder part 31 is shape | molded in the cylinder shape which can insert the edge part of the armored can 11 of the unit cell 10 without gap. The cylindrical portion 31 into which the unit cell 10 of the cylindrical battery is inserted is cylindrical, and its inner diameter is substantially equal to the outer diameter of the cylindrical battery, and precisely the inner diameter is slightly smaller than the outer diameter of the cylindrical battery. The slightly small cylindrical cylindrical portion 31 extends slightly when the unit cell 10 is inserted, and closely contacts the outer can 11 of the unit cell 10 without a gap. Further, the outer can 11 of the unit cell 10 has a slight variation in outer diameter depending on the manufacturing process. The cylindrical portion 31 formed slightly smaller than the prescribed dimension can be inserted without gaps into an outer can having a variation in outer diameter, particularly a thin outer can unit cell. This is because the cylindrical portion 31 elastically extends and absorbs the thickness variation of the outer can.

  The welding dust is generated between the connection fitting 20 and the sealing plate 12. This is because the connection fitting 20 is welded to the sealing plate 12. The welding dust which generate | occur | produces here moves to an outer peripheral direction, and makes the sealing board 12 and the exterior can 11 short-circuit at a caulking part. The battery module 50 shown in FIG. 10 moves the welding dust A smoothly and quickly shorts the sealing plate 12 and the outer can 11 with the welding dust A. The welding dust A moves between the connection fitting 20 and the sealing plate 12. The unit cell 10 is provided with the insulating low friction layer 17 on the surface facing the connection fitting 20 so that the welding dust A moves smoothly through the gap. In the illustrated battery module 50, the surface facing the connection fitting 20 is the sealing plate 12, and therefore the insulating low friction layer 17 is provided on the surface of the sealing plate 12. The insulating low friction layer 17 is provided by adhering a plastic sheet such as fluororesin or polyethylene to the surface of the sealing plate 12. The insulating low friction layer 17 is provided on the outer side of the welding projection 22 of the connection fitting 20. This is because if the insulating low friction layer 17 is present at the portion where the welding convex portion 22 is welded to the sealing plate 12, this interrupts the current, and the connection fitting 20 cannot be reliably welded to the sealing plate 12. The battery module 50 can smoothly move the welding dust A toward the outer periphery with the insulating low friction layer 17. Further, although not shown, the battery module can be provided with an insulating low friction layer on the surface facing the sealing plate of the connection fitting so that the welding dust can be moved more smoothly between the connection fitting and the sealing plate. For this reason, the welding dust can be quickly moved between the sealing plate and the outer can so as to be short-circuited, and the defective battery module can be quickly selected.

  The battery module can also prevent the welding dust from moving to prevent a short circuit due to the welding dust. As shown in FIG. 11, the battery module 50 is provided with an insulating adhesive layer 18 that adheres a welding dust A and prevents movement on the surface of the sealing plate 12 that faces the connection fitting 20 of the unit cell 10. ing. The insulating adhesive layer 18 is a pressure-sensitive adhesive layer or a layer that hardens after a certain period of time has elapsed after welding, and prevents welding dust A generated between the connection fitting 20 and the sealing plate 12 from moving. Since the battery module 50 in which the welding dust A does not move can prevent a short circuit due to the welding dust A, even if welding dust occurs, the battery module does not become defective.

  Furthermore, the battery module 50 in FIG. 12 is a facing surface of the unit cells 10 connected by the connection fitting 20, and covers the boundary between the sealing plate 12 and the outer can 11 with an insulating coating film 19 and welds dust A Prevents short circuit. The insulating coating can be provided by applying a synthetic resin paint such as an epoxy paint or a urethane paint. Since the battery module 50 insulates between the sealing plate 12 and the outer can 11 with the insulating coating film 19, the short circuit of the unit cell 10 due to the welding dust A can be prevented. For this reason, it can prevent that a welding dust generate | occur | produces and a battery module becomes defective.

  In the battery module inspection method of the present invention, the welding dust is moved to the short position, and the battery module that causes the welding dust to short-circuit the unit cell 10 is selected as a defective product. In the battery module 50 of FIG. 6, welding dust causes the sealing plate 12 and the caulking portion of the outer can 11 to be short-circuited, and the unit cell 10 is short-circuited. In order to quickly sort out battery modules in which welding dust has occurred, it is important that the generated welding dust short-circuits the unit cell 10. When the generated welding dust moves to the short position, the unit cell 10 is short-circuited. When the unit cell 10 is short-circuited, the unit cell 10 is discharged with a short current, and the voltage decreases. Therefore, when the voltage of each unit cell 10 is detected, the voltage of the shorted unit cell 10 becomes lower than the others. For this reason, the battery module in which the voltage of any of the unit cells 10 is reduced can be identified as a defective battery module due to welding dust.

  The welding dust generated when welding the connection fitting 20 is not always in the short position. Battery modules that do not have welding dust in the short position operate normally. However, when this battery module is used in, for example, a power supply device for a vehicle, the welding dust may move to a short position during use due to the influence of vehicle vibration or the like. When the welding dust moves to the short position, the performance of the unit cell 10 is significantly reduced, and the life of the unit cell 10 is remarkably shortened. For this reason, the battery module in which welding dust has occurred needs to be selected as a defective module even if the welding dust is not in the short position. However, if the welding dust is not in the short position, it cannot be identified as a defective module. For this reason, in order to select a battery module in which welding dust has occurred as a defective module, it is important to quickly move the generated welding dust to a short position.

Hereinafter, a method for quickly moving the welding dust to the short position will be described in detail.
A magnetic metal attracted by a magnetic action, such as iron or an iron alloy, is used for the connection fitting 20. The welding dust separated from the magnetic metal connection fitting 20 is attracted magnetically. For this reason, as shown in FIG. 13, a magnetic field is applied to the battery module 50 to move the welding dust generated when the connection fitting 20 is welded with a magnetic adsorption force. In the illustrated method, the magnet 40 is brought close to the boundary of the unit cell 10 from the outside. The magnet 40 is a permanent magnet or an electromagnet. The magnet 40 attracts and moves the welding dust generated at the boundary of the unit cell 10 in the outer peripheral direction. The welding dust moved in the outer peripheral direction moves to the boundary between the sealing plate 12 and the caulking portion of the outer can 11 and moves to a position where the sealing plate 12 and the outer can 11 are short-circuited. After the welding dust is moved to the short position by the magnet 40, the voltage of each unit cell 10 is detected, and if the voltage of any unit cell 10 is lowered, it is selected as a defective module.

  The connection fitting 20 is welded to the uncharged unit cell. In the battery module in this state, the weld dust that has moved to the short-circuit position short-circuits the unit cell with a small remaining capacity. The state in which the welding dust shorts the unit cell 10 is a short circuit of the unit cell 10 with a small current on the order of several mA to several tens mA, for example, as generally called “light short”. A small short current reduces the voltage drop of the unit cell 10. However, since the uncharged unit cell has a small remaining capacity, the voltage is likely to decrease, and a short in welding dust can be detected quickly. Therefore, the method of forcibly moving the welding dust to the short position and detecting the voltage of the unit cell to identify the defective module is, for example, the remaining capacity of the unit cell is 30% or less, preferably 20% or less, more preferably 10% or less, optimally not charged at all.

  The method of identifying the defective module by detecting the voltage of each unit cell compares the voltage of the detected unit cell with the voltage of the other unit cell, and the voltage of the specific unit cell is the voltage of the other unit cell. If it is lower than the set voltage, it is determined as a defective module. Further, if the voltage of each unit cell is lower than the reference voltage, it is identified as a defective module. For example, if the voltage of the unit cell is lower by several mV to several tens of mV than the voltage of other unit cells, it is determined as a defective module.

  The welding dust can be moved to the short position by forcibly vibrating the battery module. 14 to 16, vibration is applied to the battery module, and the welding dust is moved to the short position. In FIG. 14, the roller 41 is rotated in the direction indicated by the arrow, and the battery module 50 is transferred while vibrating up and down when it passes over the roller 41. In FIG. 15, a large number of protrusions 42 are provided on the surface of the roller 41 to vibrate the battery module 50 more effectively. In FIG. 16, ultrasonic vibration is applied between the unit cells 10 of the battery module 50, and the welding dust is moved to the short position by the ultrasonic vibration. The ultrasonic vibration makes the welding dust easy to move and drops the welding dust to move it to the short position. In the illustrated method, ultrasonic vibration is applied to the air between the unit cells 10 and the welding dust is ultrasonically vibrated by the air vibration. Although not shown, the welding dust can be moved to the short position by ultrasonically vibrating the battery module. In this method, the tip of the ultrasonic horn is brought into contact with the battery module, and the battery module is ultrasonically vibrated.

  Further, in FIG. 17, the battery module 50 is caused to roll on the inclined surface 43 having a downward slope, and is rotated and dropped to move the welding dust to the short position. In this method, the battery module 50 is rotated to give an impact to the welding dust and move to the short position. In particular, an impact is applied to the battery module 50 at the boundary where the inclined surface 43 moves to the horizontal plane 44, and the weld dust is moved to the short position by this impact. Although this method is not shown in the figure, the welding dust can be moved to the short position more effectively by dropping it on a plurality of inclined surfaces.

  Further, in FIG. 18, air is forcibly blown between the unit cells 10 of the battery module 50, and the welding dust is moved to the short position by this air flow. In the illustrated method, a suction pipe 45 is inserted between the unit cells 10 between the caulked portion of the outer can 11 and the insulating cap 30 like an injection needle, and air is sucked through the suction pipe 45 to weld dust. Move to the short position. In the illustrated battery module 50, ventilation openings 29 and 39 are opened in the connection fitting 20 and the insulating cap 30 in order to insert a suction pipe between the unit cells 10. The connection fitting 20 shown in the figure has a blower opening 29 in the cylindrical portion 28, and air is forcibly blown between the unit cells 10 from the blower opening 29 to move the welding dust. Further, the insulating cap 30 is provided with a ventilation opening 39 in the cylindrical portion 31, and air is forcibly blown between the unit cells 10 from the ventilation opening 39 to move the welding dust. In the illustrated battery module 50, a ventilation opening 29 provided in the cylindrical portion 28 and a ventilation opening 39 provided in the insulating cap 30 are formed as through holes as shown in FIG. 19. However, as shown in FIG. 20, the ventilation openings 29 and 39 can be opened by notching the cylindrical portions 28 and 31.

  Thus, the method of forcibly blowing air between the unit cells 10 and moving the welding dust with this air flow is that the suction pipe 45 sucks air between the connection fitting 20 and the sealing plate 12, The welding dust generated here is moved to the short position by the air flow. However, although not shown, it is also possible to blow air between the unit cells and move the welding dust to the short position by this air flow.

It is sectional drawing which shows an example of the battery module which the present applicant applied for previously. It is sectional drawing which shows another example of the battery module which the present applicant applied previously. It is sectional drawing which shows the state which the cell of the battery module shown in FIG. 1 short-circuits by welding dust. It is a side view of the battery module concerning one Example of this invention. It is a perspective view which shows the state which accommodates the battery module shown in FIG. 4 in a case. It is an expanded sectional view which shows the connection structure of the battery module shown in FIG. It is an expanded sectional view which shows the connection structure of the battery module concerning the other Example of this invention. It is a perspective view which shows the connection metal fitting of the battery module shown in FIG. It is a perspective view which shows the connection metal fitting of the battery module shown in FIG. It is an expanded sectional view which shows the connection structure of the battery module concerning the other Example of this invention. It is an expanded sectional view which shows the connection structure of the battery module concerning the other Example of this invention. It is an expanded sectional view which shows the connection structure of the battery module concerning the other Example of this invention. It is a top view which shows an example of the method of moving a welding dust to a short position. It is a perspective view which shows another example of the method of moving a welding dust to a short position. It is a perspective view which shows another example of the method of moving a welding dust to a short position. It is a top view which shows another example of the method of moving a welding dust to a short position. It is a perspective view which shows another example of the method of moving a welding dust to a short position. It is an expanded sectional view which shows another example of the method of moving a welding dust to a short position. It is a disassembled perspective view of the battery module shown in FIG. It is a disassembled perspective view of the battery module concerning the other Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Unit cell 11 ... Exterior can 12 ... Sealing plate 13 ... Convex part electrode 14 ... Gasket 15 ... Groove part 16 ... Caulking protrusion 17 ... Insulating low friction layer 18 ... Insulating adhesive layer 19 ... Insulating coating film 20 ... Connection metal fitting 21 ... Center hole 22 ... welding convex part 23 ... inner peripheral part 24 ... outer peripheral part 25 ... step part 27 ... plate part 28 ... cylindrical part 29 ... air blower opening 30 ... insulating cap 31 ... cylindrical part 32 ... insulating ring part 33 ... through-hole 35 ... Ring ridge 39 ... Blower opening 40 ... Magnet 41 ... Roller 42 ... Protrusion 43 ... Inclined surface 44 ... Horizontal plane 45 ... Suction pipe 50 ... Battery module 60 ... Terminal 70 ... Case 71 ... Lower case 72 ... Bus bar A ... Welding dust

Claims (11)

A method for inspecting a battery module in which a plurality of unit cells (10) are welded and electrically connected to a connection fitting (20) between the batteries,
Welding dust (A) generated when welding the metal fitting (20) by using a magnetic metal attracted by magnetic action to the metal fitting (20) and applying a magnetic field to the battery module (50) The battery module is inspected by detecting the short-circuit of the welding dust (A) by detecting the voltage of the unit cell (10) by moving the magnet with magnetic attraction force. A method for inspecting a battery module in which a plurality of unit cells (10) are welded and electrically connected to a connection fitting (20) between the batteries,
The battery module (50) is forcibly vibrated, the welding dust (A) generated when welding the connection fitting (20) is moved, the voltage of the unit cell (10) is detected, and the welding dust (A) A battery module inspection method for detecting a short circuit.   The battery module inspection method according to claim 2, wherein the battery module (50) is forcedly vibrated by being moved onto the plurality of rollers (41).   The battery module inspection method according to claim 2, wherein the battery module (50) is dropped on the inclined surface (43) to forcibly vibrate. A method for inspecting a battery module in which a plurality of unit cells (10) are welded and electrically connected to a connection fitting (20) between the batteries,
When the battery module (50) is ultrasonically vibrated or ultrasonic vibration is applied between the unit cells (10), the welding dust (A) generated when welding the connection fitting (20) by ultrasonic vibration is moved. A battery module inspection method for detecting a short circuit of the welding dust (A) by detecting the voltage of the unit cell (10). A method for inspecting a battery module in which a plurality of unit cells (10) are welded and electrically connected to a connection fitting (20) between the batteries,
Air is forcibly blown between the unit cells (10) of the battery module (50), and with this air flow, the welding dust (A) generated when welding the connection fitting (20) is moved, and the unit cell (10 The battery module inspection method detects the short of welding dust (A) by detecting the voltage of). A battery module in which a connection fitting (20) is disposed between a plurality of unit cells (10), and the connection fitting (20) is welded and electrically connected to the unit cell (10),
A battery module in which an insulating low friction layer (17) for smooth movement of the welding dust (A) is provided on the surface of the unit cell (10) facing the connection fitting (20). A battery module in which a connection fitting (20) is disposed between a plurality of unit cells (10), and the connection fitting (20) is welded and electrically connected to the unit cell (10),
A battery module in which an insulating adhesive layer (18) for preventing movement by adhering a welding dust (A) is provided on the opposing surface of the unit cells (10) connected by the connection fitting (20). A battery module in which a connection fitting (20) is disposed between a plurality of unit cells (10), and the connection fitting (20) is welded and electrically connected to the unit cell (10),
It is the facing surface of the unit cells (10) connected by the connection fitting (20), and the boundary between the sealing plate (12) and the outer can (11) is covered with an insulating coating (19) and welded ( A battery module configured to prevent the short circuit of A). A battery module in which a connection fitting (20) is disposed between a plurality of unit cells (10), and the connection fitting (20) is welded and electrically connected to the unit cell (10),
The connecting fitting (20) is located inside the cylindrical portion (28) and the cylindrical portion (28) in which the end of the outer can (11) of the unit cell (10) is inserted and electrically connected. Having a plate part (27) welded to the sealing plate (12) of the battery (10),
The tube portion (28) is provided with a blower opening (29) for forcibly blowing the air moving the welding dust (A) between the unit cells (10), and the unit cell (10 The battery module is configured such that the welding dust (A) can be moved between the unit cells (10) by forcibly blowing air between them. A battery module in which a connection fitting (20) is disposed between a plurality of unit cells (10), and the connection fitting (20) is welded and electrically connected to the unit cell (10),
An insulation cap (30) for preventing a short circuit of the unit cell (10) is provided on the end surface of the unit cell (10), and this insulation cap (30) is provided at the end of the outer can (11) of the unit cell (10). A cylindrical part (31) for inserting the insulating ring part (32) that is inside the cylindrical part (31) and insulates the connection fitting (20) and the outer can (11),
The tube portion (31) is provided with a ventilation opening (39) for forcibly blowing the air moving the welding dust (A) between the unit cells (10), and the unit cell (10 The battery module is configured such that the welding dust (A) can be moved between the unit cells (10) by forcibly blowing air between them.

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