JP2011034731A - Inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To non-destructively and surely detect welded part defects obtained by welding inter-cells connectors each other in cells adjacent to each other through a battery case barrier plate in a through-hole of the barrier plate. <P>SOLUTION: This inspection device inspects the state of the welded portion of a pair of the inter-cell connectors 14A, 14B welded through the through-hole 21A in a lead acid battery 12 having the inter-cell connectors 14A, 14B derived from straps 13A, 13B to which the lug parts of same polarity electrode plates are collectively welded respectively, and the battery case barrier plate 21 having the through-hole 21A, using an electromagnetic induction crack detecting method. The inspection device includes a detection coil 11 to generate and transmit AC magnetic flux, and passing it the welded part, and receive the AC magnetic flux after passing the welded parts to output an inspection signal, a magnetic path forming member 33 to lead the AC magnetic flux before it passes the welded part and goes toward the lug parts 23A, 23B to the receiving side of the detection coil, and a determination part to determine whether the welded parts are proper or not based on the detection signal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an inspection apparatus, and more particularly to an inspection apparatus capable of nondestructively inspecting the welded state of an inter-cell connector in a monoblock lead-acid battery.

Conventionally, several methods have been used for inter-cell connection of lead acid batteries.
As a typical method, a partition wall penetration method (through partition method) is known (for example, see Patent Document 1). In this through partition system, intermediate poles in adjacent cell chambers are welded and connected to each other through a partition wall through a partition wall. This has the advantage that the conductor required for connection can be shortened compared to the partition over method that has been used conventionally, so that the voltage characteristics are improved and the amount of lead alloy used can be reduced. .

In the weld portion of the lead-part battery of the through partition system, the inter-cell connector (intermediate pole column) is obtained by welding and integrating the ear portions of a plurality of electrode plates. And the connection body between cells is welded in the through-hole provided in the partition between the adjacent cells. In this through partition method, resistance welding is adopted because the characteristics required for the welded portion are ensured and the mass productivity is excellent.
In the resistance welding of the through partition method, the inter-cell connection body (intermediate pole column) is arranged so as to sandwich the through hole provided in the partition between the cells.
Next, the electrode is pressed and brought into contact with the positive and negative intercellular connecting bodies, and the intercellular connecting bodies are pressed and deformed by the electrodes, introduced into the through holes of the partition walls between the cells. The connecting body between both cells is brought into contact inside. Thereafter, a predetermined welding current is passed through the electrodes, and resistance welding is performed on the contact surfaces of the connection bodies between the cells.

Japanese Patent Laid-Open No. 10-106535

By the way, if there are insulators or impurities between the positive and negative intercellular connections during this resistance welding, welding will be insufficient, or the lead alloy that constitutes the intercellular connections will melt and molten lead will scatter. There is a possibility that it will be.
In addition, there is a problem that it is difficult to find from the appearance even in a state where welding is insufficient or molten lead is scattered.
Furthermore, the scattering of molten lead at the time of welding may cause malfunctions such as a malfunction during the subsequent chemical conversion process or in actual use, and it is hoped that the welded state of the inter-cell connected body can be reliably detected without destruction. It was rare.
Therefore, an object of the present invention is to ensure non-destructive defects in the welded portion obtained by welding the inter-cell connecting members arranged in the adjacent cells via the battery case partition walls in the through holes of the partition walls. It is an object of the present invention to provide an inspection apparatus capable of detecting the above.

  In order to solve the above-mentioned problems, the present invention has a plurality of straps made of a metal material in which the ears of the same polarity electrode plate are each welded together, an inter-cell connecting body derived from each of the straps, and a through hole In an inspection apparatus for inspecting the state of a welded portion of the pair of inter-cell connecting bodies welded through the through holes in a lead storage battery having a battery case partition wall using an electromagnetic induction flaw detection method, A detection coil that generates and transmits, passes through the weld, receives the alternating magnetic flux after passing through, and outputs an inspection signal; and describes the alternating magnetic flux that passes through the weld and travels toward the ear. The magnetic path forming member led to the receiving side of the detection coil, and a determination unit that determines the suitability of the state of the welded part based on the inspection signal.

According to the said structure, a detection coil produces | generates and transmits alternating current magnetic flux, and lets the said welding part pass.
As a result, the magnetic path forming member guides the alternating magnetic flux that has passed through the welded portion and headed toward the ear portion to the receiving side of the detection coil, and the detection coil outputs an inspection signal to the determination unit based on the received alternating magnetic flux. .
A discrimination | determination part discriminate | determines the suitability of the state (welding state in a welding part) of the welding part of the connection body between cells based on an inspection signal.

  Therefore, the AC magnetic flux passes through the welded portion and is guided to the receiving side of the detection coil before going to the ear portion. Therefore, the influence of the shape of the collective weld portion between the strap and the ear portion, or the weld state of the collective weld portion. Therefore, the suitability of the welded state of the welded portion of the inter-cell connected body can be determined, and the suitability of the welded state can be determined more accurately.

In this case, a cover portion is provided so as to face the detection coil so that the magnetic path forming member and the detection coil do not directly contact the inter-cell connection body, and the cover portion and the detection coil are integrally held. It is preferable to provide an inspection probe.
According to the above configuration, the AC magnetic flux transmitted from the detection coil can be reliably passed through the welded portion and detected before heading to the ears by simply placing the inspection probe at an appropriate position with respect to the inter-cell connector. Since the coil can be guided to the receiving side, the inspection can be performed more easily.

The magnetic path forming member may be made of a nonmagnetic material having a relative permeability larger than that of a metal material constituting the strap.
According to the above configuration, since the alternating magnetic flux after passing through the welded portion can be reliably guided to the receiving side of the detection coil before going to the ear portion, the shape or welding of the collective weld portion between the strap and the ear portion The inspection can be performed reliably without being affected by the condition.

  According to the present invention, it is possible to reliably detect non-destructive defects in the welded portion of the inter-cell connecting portion without being affected by the shape of the collective welded portion between the strap and the ear or the welding state of the collective welded portion. There is an effect that can be.

It is a general | schematic block diagram of the inspection apparatus of embodiment. It is an external appearance perspective view of a detection probe. It is operation | movement explanatory drawing of a detection probe. It is explanatory drawing of the non-defective product / defective product determination result of the lead storage battery provided with the battery case having the cell chamber.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration block diagram of an inspection apparatus according to an embodiment.
The inspection apparatus 10 has a detection coil 11 and is roughly divided to inspect the welded portion 15 so as to face the welded portion 15 of the inter-cell connectors 14A and 14B derived from the straps 13A and 13B constituting the lead storage battery 12. An inspection probe 16, a reference coil 17, and an inspection apparatus main body 18 that determines the suitability of the welded portion 15 based on inspection signals SD1 and SD2 from the detection coil 11 and the reference coil 17.

Next, the configuration of the lead storage battery to be inspected will be described. In addition, in FIG. 1, the fragmentary sectional view of the battery case of the 6-cell monoblock type lead-acid battery in which the inside of the battery case is divided into six cell chambers is shown, and two adjacent cell chambers 22 are shown. Although it is actually a lead storage battery having a battery case composed of six cell chambers 22.
The lead storage battery 12 is a through-partition type monoblock lead storage battery, and the inside of the battery case is partitioned into cell chambers 22 by battery case partition walls 21, and through holes 21 </ b> A are formed above the battery case partition walls 21. Yes.
Each cell chamber 22 accommodates a group of electrode plates in which a plurality of positive electrode plates and negative electrode plates (not shown) are alternately stacked via separators (not shown). Reference numeral 13A denotes two cell chambers 22. Of these, a plurality of ears 23 </ b> A of only the positive electrode plate of the electrode plate group housed in one cell chamber 22 is formed by a cast-on strap method (COS) or the like. Reference numeral 13 </ b> B is a strap in which a plurality of ears 23 </ b> B of only the negative electrode plate of the electrode plate group housed in the other cell chamber 22 is formed by a cast-on strap method (COS) or the like.
Each strap 13A, 13E is formed of a metal material (such as a lead alloy). The inter-cell connecting bodies 14A and 14B that stand upward are led out from the end portions of the straps 13A and 13B on the one end side. The inter-cell connecting bodies 14A and 14B are provided in the through holes 21A of the battery cell partition wall 21. It is integrated by welding.

Then, the positive inter-cell connection body 14A and the negative inter-cell connection body 14B are arranged in close contact with each other through the through-hole 21A and face each other, resistance welded in a pressure contact state, and the weld 15 Is formed.
Then, a positive electrode terminal and a negative electrode terminal respectively led out from the straps 13A and 13B of the cell chambers 22 at both ends (not shown) are formed to rise upward via a battery case cover (not shown) to form a lead storage battery. It is composed.

FIG. 2 is an external perspective view of the detection probe.
FIG. 3 is an explanatory diagram of the operation of the detection probe.
The inspection probe 16 prevents the detection coil 11 from directly touching the detection coil 11 that generates AC magnetic flux, the signal cable 31 drawn from the detection coil 11, and the metal material that constitutes the inter-cell connectors 14A and 14B at the time of inspection. The magnetic flux that passes through the resin-made cover portion 32 and the welded portion 15 in the inter-cell connectors 14A and 14B and captures the alternating magnetic flux before going to the ear portions 23A and 23B and guides it to the receiving side of the detection coil 11 A path forming member 33.

Here, the magnetic path forming member 33 will be described.
The magnetic path forming member 33 is made of a nonmagnetic material having a relative permeability larger than that of the metal material (lead alloy) constituting the straps 13A and 13B.
Specifically, when the relative permeability of the straps 13 </ b> A and 13 </ b> B is 0.999, stainless steel (SUS304) having a relative permeability = 1.015 is used as the magnetic path forming member 33.
In this case, in this embodiment, the magnetic path forming member 33 has a plate shape, but when viewed from the strap 13A, 13B side at this time, the lower side is arranged so that the detection coil 11 having the diameter xφ and the thickness L1 cannot be seen. It is preferable to determine the dimensions of the magnetic path forming member 33 so as to cover the width W ≧ x and the depth L2 ≧ L1.

Further, even if the width W or the depth L2 is smaller than this preferred dimension, there may be no practical problem. In this case, the voltage applied to the detection coil 11 or the frequency of the alternating magnetic flux is appropriately set. Is preferred. Here, when the applied voltage is changed, the inspection range is changed, and when the frequency of the alternating magnetic flux is changed, the ease of transmission of the magnetic lines of force is changed.
That is, when the applied voltage is increased, the inspection range is widened, and when the frequency of the alternating magnetic flux is increased, it is difficult to transmit the magnetic lines of force.
Further, the magnetic path forming member 33 is not a plate, but a semi-cylindrical shape in which a cylinder is cut at a diameter portion, a cylindrical shape capable of covering the periphery of the detection coil 11, or a cylindrical shape having a rectangular cross section. May be.

Next, the arrangement relationship between the detection coil 11 and the straps 13A and 13B will be described in detail.
As shown in FIG. 2, the detection coil 11 has a substantially donut shape, and welds the inter-cell connectors 14A and 14B led out from the straps 13A and 13B into the magnetic flux path in the generated magnetic field. As shown in FIG. 3, the rotation center axis CC of the detection coil 11 is preferably arranged so as to substantially coincide with the center of the through hole 21 </ b> A of the battery case partition 21 so that the welded portion 15 obtained by the above is located.
For this reason, the thickness of the magnetic path forming member 33 is preferably set to a thickness that does not unnecessarily prevent the rotation center axis CC of the detection coil 11 from being substantially coincident with the center of the through hole 21A.

Further, since the detection coil 11 is preferably as close to the inter-cell connecting bodies 14A and 14B as possible from the viewpoint of the utilization efficiency of the alternating magnetic flux, it is disposed immediately on the back surface of the cover portion 32 as shown in FIG. In this case, the thickness of the cover part 32 is preferably about 0.5 to 1 mm.
Next, the inspection principle will be described.
The inspection signal SD2 transmitted, received, and output by the reference coil 17 is uniform and does not fluctuate because the detection target is the atmosphere not affected by anything other than geomagnetism.

  On the other hand, the inspection signal SD1 transmitted and received and output by the detection coil 11 is greatly influenced by the state of the welded portion 15 (the presence of non-uniform layers such as impurities, voids, cracks, etc.) Since the effective path length of the magnetic field lines changes and the amplitude and phase of the voltage generated by the AC magnetic flux received by the detection coil 11 change, the inspection apparatus to which the corresponding inspection signal SD1 is input. The main body 18 compares the amplitude and phase of the voltage generated by the AC magnetic flux corresponding to the inspection signal SD2 and analyzes them to determine whether the welded part 15 is good or defective.

  For example, the waveform of the inspection signal SD1 corresponding to the defective product is higher in voltage and out of phase with respect to the waveform of the inspection signal SD2. Accordingly, by determining in advance a threshold value for identifying a non-defective product / defective product for the voltage difference or the phase difference, the inspection apparatus body 18 determines that the product is defective when the threshold value is exceeded. Yes. In this case, since the phase difference obtained by the inspection varies greatly depending on the shape and material of the strap and the ear part, the threshold value TH for determining the non-defective product / defective product is determined by an experiment or the like depending on the inspection object. Become.

Next, a specific operation will be described.
First, the inspection apparatus body 18 outputs AC power having a preset voltage and frequency to the detection coil 11 and the reference coil 17.
As a result, an alternating magnetic flux having a predetermined frequency is transmitted from the detection coil 11 and the reference coil 17.
In this state, the operator holds the grip 16A of the inspection probe 16, places the inspection probe 16 on the upper surface of the strap 13B, and presses the cover 32 against the inter-cell connector 14B as shown in FIG. Then, the rotation center axis CC of the detection coil 11 is positioned so as to substantially coincide with the center of the welded portion 15.

Above the center of the welded portion 15, the AC magnetic flux transmitted from the transmission side of the detection coil 11 (the left end surface of the detection coil 11 in FIG. 3) follows a path as indicated by solid lines MG <b> 1 and MG <b> 2 in FIG. 3. Then, it passes through the welded portion 15 and is received again on the receiving side of the detection coil 11 (the right end surface of the detection coil 11 in FIG. 3).
On the other hand, below the center of the welded portion 15, the AC magnetic flux transmitted from the detection coil 11, when the magnetic path forming member 33 is not provided, is along the path indicated by the broken line MG <b> 3 in FIG. 3. Will be received by the detection coil 11 again. As a result, it will be influenced by the material and shape of the ear | edge part 23A welded under the strap 13A and the ear | edge part 23B welded under the strap 13B, and the exact state of the welded part 15 will be grasped. In this embodiment, since the plate-like member of SUS304 is arranged as a magnetic path forming member 33 at a position between the detection coil 11 and the strap 13B, transmission from the detection coil 11 is performed. As shown by the solid line MG <b> 2 in FIG. 3, the AC magnetic flux is received by the detection coil 11 again through or near the magnetic path forming member 33 where the AC magnetic flux passes more easily than the strap 13 </ b> B. It will be.

  As a result, the inspection signal SD1 including the information of the welded portion 15 is obtained without being affected by the material and shape of the ear 23A welded below the strap 13A and the ear 23B welded below the strap 13B. It is possible to obtain.

FIG. 4 is an explanatory diagram of a non-defective / defective product determination result of a lead storage battery including a battery case having a cell chamber.
When one lead storage battery 12 is a battery case having six cell chambers 22, there are five welds 15, which is equal to the number of battery wall partitions 21.
Therefore, when the measurement results are obtained by the above-described method for the welded portions of the two lead storage batteries A and B, the obtained phase difference (°) is as shown in FIG.
In this case, assuming that a phase difference of 20 ° is set as the threshold TH for defective product discrimination, one lead storage battery A has a threshold TH = phase difference of 20 ° or less in all the welds 15. Therefore, the inspection apparatus body 18 determines that the product is non-defective.

On the other hand, the other lead storage battery B is determined to be defective by the inspection apparatus body 18 because the phase difference obtained by the inspection of the third welded portion 15 exceeds the threshold value TH = phase difference of 20 °. It was to be done.
In this case, when the magnetic path forming member 33 is provided for the same lead storage battery, when the welded portion 15 is a non-defective product, the value is compared with the case where the magnetic path forming member 33 is not provided. In the case where the phase difference is detected to be small and the welded part 15 is a defective product, the phase difference is detected to be large compared to the case where the magnetic path forming member 33 is not provided.
For this reason, in the conventional case where the magnetic path forming member 33 is not provided, the threshold value TH must be set to a larger value (for example, the threshold value TH is conventionally set to a phase difference of 30 °), and the inspection accuracy is improved. Although it could not be increased too much, by providing the magnetic path forming member 33 as in the present embodiment, the threshold value TH can be set to a small value as described above, and it is more reliable and highly accurate. It has been found that defective products can be identified.

  As described above, according to the present embodiment, the alternating magnetic flux generated by the detection coil 11 passes through the welded portion 15 of the inter-cell connectors 14A and 14B and returns to the detection coil 11. At this time, the alternating magnetic flux before passing through the welded portion 15 in the inter-cell connectors 14A and 14B to the ear portions 23A and 23B by the magnetic path forming member 33 is captured and hardly passes through the ear portions 23A and 23B side. Since it is guided to the receiving side of the detection coil 11, it is possible to obtain a good inspection signal without causing deterioration of the inspection signal (increase in noise or the like) due to them, and as a result, it is possible to reliably produce a good / A defective product can be determined.

  In the above description, the case where stainless steel is used as the magnetic path forming member 33 has been described. However, the relative permeability larger than the effective relative permeability of the AC magnetic flux path including the straps 13A and 13B and the ear portions 23A and 23B. And a non-magnetic material (approximately less than 1.02 as a relative permeability) can be similarly applied.

DESCRIPTION OF SYMBOLS 10 Inspection apparatus 11 Detection coil 12 Lead storage battery 13A Strap 13B Strap 14A, 14B Connection between cells 15 Welding part 16 Inspection probe 17 Reference coil 18 Inspection apparatus main body (discriminating part)
21 Battery case 21A Through hole 22 Cell chamber 23A, 23B Ear 32 Cover 33 Magnetic path forming member CC Rotation center axis SD1, SD2 Inspection signal TH threshold

Claims (2)

In a lead-acid battery having a plurality of straps made of metal materials in which the ears of the same polarity electrode plates are respectively welded together, an inter-cell connecting body derived from each of the straps, and a battery case partition wall having a through hole, In the inspection apparatus for inspecting the state of the welded portion of the pair of inter-cell connected bodies welded through the through hole using an electromagnetic induction flaw detection method,
A detection coil that generates and transmits an alternating magnetic flux, passes through the weld, receives the alternating magnetic flux after passage, and outputs an inspection signal;
A magnetic path forming member that guides the alternating magnetic flux before passing through the weld and toward the ear to the receiving side of the detection coil;
Based on the inspection signal, a determination unit that determines the suitability of the state of the weld,
An inspection apparatus comprising: The inspection apparatus according to claim 1,
2. The inspection apparatus according to claim 1, wherein the magnetic path forming member is made of a nonmagnetic material having a relative permeability larger than a relative permeability of a metal material constituting the strap.

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