JP4765345B2 - Lead storage battery manufacturing method and manufacturing apparatus - Google Patents

Description

  The present invention relates to a manufacturing method for resistance welding between cells of a lead storage battery, and a manufacturing apparatus therefor.

  The lead acid battery is a battery that uses lead dioxide as a positive electrode active material, metal lead as a negative electrode active material, and dilute sulfuric acid as an electrolyte. In general, lead-acid batteries form an electrode plate group by laminating an arbitrary number of positive and negative electrodes through a porous and insulating separator, and these are housed in a battery case to form a cell and inject dilute sulfuric acid. Configured. As its application, it is widely used for starting automobiles, electric cars, uninterruptible power supplies and so on. In particular, in applications such as starting automobiles and electric cars, severe impacts and vibrations when the vehicle travels are applied to the battery. Therefore, the reliability of these impacts and vibrations is regarded as important.

  Since lead-acid batteries have a low cell voltage of about 2V in principle, generally, a plurality of cells are assembled regardless of the battery type or application, and connected between cells in series or in parallel as required. It is common to use an integrated monoblock structure that forms a capacitor and a capacitor.

  In particular, when an impact or vibration as described above is applied to the connection part between cells, stress is generated in the connection part between cells, cracking or breaking occurs in the connection part, or corrosion starting from the crack proceeds. There is. Due to such factors, the battery becomes unusable when the inter-cell connection portion is damaged. Therefore, high reliability is required for the inter-cell connection portion.

  On the other hand, resistance welding is widely used as a method for connecting cells between lead-acid batteries for starting automobiles and electric vehicles. In resistance welding, through holes are provided in the partition walls that define the cell chambers, and connecting bodies provided on straps that electrically collect the same polarity plates of the electrode plate group of each cell are arranged to face each other through the through holes. The bodies are pressed with an energizing electrode and brought into contact with each other, a welding current is applied between the energizing electrodes, and welding is performed by Joule heat during energization.

  The welded state of the connection body by resistance welding is greatly influenced by the electrical resistance value of the connection body, the contact resistance value obtained when the connection bodies are brought into contact with each other in the through hole, and the contact resistance value between the connection body and the energization electrode. These variations cause excessive welding or insufficient welding.

  In general, the determination of the weld state of the connection part between cells is performed by taking out the weld part and measuring the breaking strength, or confirming the state of the fracture surface or the lead alloy crystal state of the weld part cross section. However, since such a method is a destructive test, 100% inspection is impossible and is performed as a sampling test.

  Unlike the destructive inspection as described above, several methods have been tried to inspect the welded portion nondestructively. For example, Patent Document 1 measures the distance and displacement between the welds between the cells facing each other through the through-holes before and after welding, and compares the distances and displacement changes to estimate the welding state. Is disclosed.

However, according to Patent Document 1, there are cases where the inside is excessively welded or insufficiently welded even if the displacement amount during resistance welding is within a normal range, and a defective product is determined as a good product. There was a case.
JP 2002-324574 A

  An object of the present invention is to provide means for accurately determining the quality of a welded state of a resistance welded portion by nondestructive inspection without performing destructive inspection in the resistance welding step between cells of the lead storage battery as described above. And

In order to solve the above-described problem, the invention according to claim 1 of the present invention stores an electrode plate group in which a connecting body is provided in a plurality of cell chambers partitioned by partition walls in a battery case, and In the adjacent electrode plate groups, the connecting members provided in these electrode plate groups are opposed to each other through the through holes provided in the partition walls, and these connecting members are pressed by the energizing electrodes to bring the connecting members into contact with each other. In a method for manufacturing a lead-acid battery in which a welding current is passed between and resistance welding between connected bodies, the temperature (T1) of the connected body before energization is measured, and the temperature (T2) of the connected body after a predetermined time after the end of energization. The temperature difference (T2−T1) between the temperature (T1) and the temperature (T2) is compared with a pass / fail judgment standard obtained from the relationship with the weld nugget width (W) measured in advance , A method for manufacturing a lead-acid battery, characterized in that a pass / fail judgment is performed Than is.

  The invention according to claim 2 of the present invention is characterized in that in the method for manufacturing a lead-acid battery according to claim 1, the temperature (T1) and the temperature (T2) are measured using a non-contact temperature sensor. Is.

Furthermore, the invention according to claim 3 of the present invention is the electrode plate group in which the electrode plate group in which the connection body is provided in the plurality of cell chambers partitioned by the partition wall in the battery case is housed, and adjacent to each other through the partition wall. The connection bodies provided in these electrode plate groups are opposed to each other through through holes provided in the partition walls, and these connection bodies are pressed with current-carrying electrodes so that the connection bodies are brought into contact with each other, and a welding current is passed between the current-carrying electrodes. In the lead-acid battery manufacturing apparatus for resistance welding between the connected bodies, a temperature measuring means for measuring the temperature (T1) of the connected body before energization, and the temperature (T2) of the connected body after a predetermined time after the end of energization , A lead-acid battery characterized by comprising pass / fail judgment means for judging pass / fail of a welded part by comparing with a pass / fail judgment standard obtained from a relationship with a difference (T2-T1) measured in advance of a weld nugget width (W) . A manufacturing apparatus is shown.

  The invention according to claim 4 of the present invention is characterized in that, in the lead-acid battery manufacturing apparatus of claim 3, a non-contact temperature sensor is used as the temperature measuring means.

  According to the present invention, since Joule heat generated at the time of resistance welding is measured as a temperature rise of the welded portion, it is possible to accurately determine a welding failure such as excessive welding or insufficient welding.

  Hereinafter, a lead-acid battery manufacturing apparatus and a manufacturing method according to embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a state in which a non-welded in-process battery 201 connected between cells is arranged in the lead storage battery manufacturing apparatus 101 according to the present invention before welding.

  Here, the work-in-process battery 201 has a plurality of cell chambers 204 partitioned by a partition wall 203 in a battery case 202, and has a configuration in which an electrode plate group 206 provided with a connection body 205 is accommodated in each cell chamber 204. Have. In the electrode plate group 206, a positive electrode plate 207 and a negative electrode plate 208 are combined via a separator 209, and a shelf portion 210 for collectively welding the ears of the same polarity electrode plates of the positive electrode plate 207 and the negative electrode plate 208 is provided. Have. The connection body 205 is provided on the shelf 210.

  The partition wall 203 is provided with a through-hole 211, and the connecting body 205 is disposed opposite to the through-hole 211 in the adjacent electrode plate group 206.

  As shown in FIG. 1, the lead storage battery manufacturing apparatus 101 of the present invention is provided with a current-carrying electrode 102 as in the case of a conventional resistance welding apparatus. The energizing electrode 102 includes a power supply device 103 for supplying welding power and a welding controller 104 for controlling the welding current / voltage and welding time. In addition, a pressurizing unit 105 is provided for pressurizing the connection body 205 by the energizing electrode 102 and bringing the connection bodies 205 into contact with each other. Note that the pressing force of the pressurizing means 105 is controlled by the welding controller 104.

  Next, as shown in FIG. 3, energization is performed between the energization electrodes 102 in a state where the connection bodies 205 are in contact with each other with a predetermined pressure, and the vicinity of the contact portion is caused by Joule heat generated at the contact portion. Melt. When a predetermined welding time has elapsed, the energization is stopped, and cooling and solidification of the molten contact portion proceeds. During cooling and solidification, pressurization of the connection body 205 by the energizing electrode 102 is maintained, and cracks and bubbles remaining in the welded portion are suppressed. A weld nugget 212 is formed in the melted and solidified portion.

  When the cooling and solidification is completed, pressurization of the connection body 205 by the energizing electrode 102 is released, and welding is completed. The energizing electrode 102, the power supply device 103, the welding controller 104, the pressurizing means, and the operation thereof are also used in the conventional connection method between lead-acid battery cells and the device thereof. It does not characterize the manufacturing method or the manufacturing apparatus.

  In the lead storage battery manufacturing apparatus 101 of the present invention, in the electrode plate group 206 adjacent to each other via the connection body 205, temperature measuring means 105 for measuring the temperature of the connection body 205 provided in the electrode plate group 206. have. The temperature measuring means 105 measures the temperature (T1) of the connection body 205 before energization (before welding) and the temperature (T2) of the connection body 205 after a predetermined time after the end of energization. Based on the values of the temperature (T1) and the temperature (T2), the quality determination unit 106 determines the quality of the weld.

  In the pass / fail judgment means 106, a temperature difference (ΔT = T2−T1) between the temperature (T2) and the temperature (T1) is calculated, and when the temperature difference (ΔT) is within a predetermined range, an appropriate amount of welding heat is generated, It is determined that the welding state is appropriate.

  When the temperature difference (ΔT) exceeds the predetermined range, the quality determination means 106 determines that the generated welding heat amount is excessive and the welding is excessive.

  When the temperature difference (ΔT) is less than the predetermined range, the quality determination means 106 determines that the generated heat of welding is too small and the welding is insufficient.

Determination value setting for determining whether the temperature difference (ΔT) is good or not is set based on the correlation between the temperature difference (ΔT) and the welding state investigated in advance. As an index of the welding conditions, adopting the width of the welding nugget 212 (W), a determination value setting for quality determination from the correlation between the temperature difference (△ T).

  In addition, since the state of heat rise and cooling during welding changes depending on the shape of the connecting body 205 and the shelf 210, it is necessary to set a determination value for pass / fail judgment according to these shapes.

  Furthermore, it is necessary to make the timing for measuring the temperature (T2) of the connection body 205 after the end of welding constant. FIG. 3 is a schematic diagram showing a change over time of the connection body temperature (T) in the welding process. The temperature of the connection body 205 before energization is influenced by the ambient temperature and hardly changes with time, and may be regarded as constant. On the other hand, after a time lag of several hundred milliseconds to several seconds immediately after the start of energization, the temperature of the connection body 205 begins to rapidly increase, and after reaching the maximum temperature, gradually cools and decreases in temperature.

  Although the temperature of the melted part of the connection body 205 is as high as 800 ° C. due to energization, the surface temperature of the connection body 205 immediately after the end of welding is not greatly increased from the temperature before welding. Thereafter, with the passage of time, the heat generated in the welded portion is conducted to the surface of the connection body 205, and the surface temperature starts to rise. Thereafter, heat is radiated from the surface of the connection body 205 to the energizing electrode 102 and the atmosphere, and cooling proceeds.

  As described above, since the temperature of the connected body changes depending on the time from the end of energization, it is necessary to set the temperature (T2) to a predetermined time after the end of energization and make the measurement timing constant. As an example, if measurement of the temperature (T2) is completed while the energizing electrode for several seconds immediately after energization is held in a pressurized state or immediately after the pressurized state is released, within the welding process Since the pass / fail judgment can be completed, it is preferable in terms of shortening the process time.

  As for the temperature (T2), a conventional contact-type temperature measuring device using a thermocouple can be used. However, since the variation in measurement timing affects the determination accuracy, the temperature measuring means 105 is connected to the connection body 205. It is more preferable to use a non-contact temperature measuring device that measures the temperature of the connection body 205 from the emitted infrared rays.

  However, the non-contact temperature measuring means 105 by infrared detection may cause a measurement error depending on the degree of surface gloss of the connection body 205, so that the reflected light of the connection body 205 is suppressed between the temperature measurement means 105 and the connection body 205. It is preferable to dispose a polarizing filter (not shown) or to apply a reflection suppressing process such as black matte paint application to the temperature measurement position of the connection body 205.

  According to the configuration of the present invention as described above, the welded state of the inter-cell resistance welded portion of the lead storage battery can be determined non-destructively and with good quality, so it is extremely effective in improving the reliability of the lead storage battery. is there.

  Specific examples of the present invention will be described below.

  First, a polypropylene resin battery case was prepared as the battery case 202 shown in FIG. The interior is partitioned into cell chambers 204 by five partition walls 203. The thickness of the partition wall was 1.30 mm, and a through hole 211 having a diameter of 10 mm corresponding to the connection body 205 was used.

  In the cell chamber 204, the electrode plate group 206 is accommodated, and the connection body 205 is disposed in a state of facing each other through the through hole 211. In the present embodiment, the shelf 210 and the connection body 205 are Pb-3.0 mass% Sb alloy, the thickness of the shelf 210 is 7.0 mm, and the height dimension (h) of the connection body 205 is 20.5 mm. The width dimension (d) = 18.0 mm and the thickness dimension (t) = 5.0 mm.

  As the energizing electrode 102, a copper alloy tip having a truncated cone shape is used, and the tip diameter is 6.0 mm.

  As shown in FIG. 4, the temperature measurement position of the connection body 205 is a position excluding the position 401 where the energization electrode 102 of the connection body 205 is disposed, and a member such as an arm for holding the energization electrode 102. Set the position so that it does not interfere with. FIG. 4 shows an example in which the temperature measurement position 402 is arranged on the side portion of the position 401.

  Next, the energization electrode 102 is driven to pressurize the connecting bodies 205. And the surface temperature of the connection body 205 in the temperature measurement position before electricity supply was measured as temperature (T1) using the infrared detection type non-contact-type temperature sensor. The temperature (T1) may be performed before the pressure application operation of the energizing electrode 102.

  Here, the pressure applied by the energizing electrode 102 was set to 500 MPa. And electricity supply was performed between the electrodes 102 for electricity supply. The energization conditions were 60 Hz alternating current (9000 A) energized for 8 cycles, that is, 8/60 seconds, immediately after that, the applied pressure was increased to 700 MPa, and this applied pressure was maintained for 1.00 seconds. By increasing the applied pressure and allowing the cooling to proceed, cracks and residual bubbles in the weld nugget 212 can be suppressed.

  And the temperature (T2) of the connection body 205 in the temperature measurement position 402 was measured 1.20 seconds after the end of energization for 8/60 seconds.

  The pass / fail judgment unit performs pass / fail judgment from the value of the temperature difference (ΔT = T2−T1) between the temperature (T2) and the temperature (T1). As a pass / fail judgment criterion, a product having a temperature difference (ΔT) in the temperature range of 26.5.0 to 38.0 ° C. was judged as a non-defective product, and other products were judged as defective products.

  As shown in FIG. 5, the pass / fail judgment standard is set by measuring the relationship between the temperature difference (ΔT) and the welding nugget width (W) in advance and setting the temperature difference (ΔT) from the normal welding nugget width. To do. However, since the weld nugget width (W) varies even at the same temperature difference, it goes without saying that the criterion should be set by statistical processing within a range in which a defective product is not erroneously determined as a good product.

  In the example shown in FIG. 5, the normal welding nugget width is set to 3.0 mm to 4.5 mm, and the determination criterion is 26.5 with respect to the temperature difference (Δt) 25.0 to 39.5 ° C. corresponding to that case. Set to ~ 38.0 ° C.

  When the connection body determined to be non-defective according to such a determination criterion is disassembled and the weld nugget width (W) is measured by n number = 100, the weld nugget width (W) is 3.3 to 4.2 mm. Those that were determined to be non-defective by the method and apparatus of the present invention were confirmed to be all non-defective products by destructive inspection.

  As described above, according to the present invention, the quality of the welded state of the inter-cell connecting portion of the lead storage battery can be accurately determined without performing a destructive inspection.

  In the examples, the correlation between the weld nugget width (W) and the temperature difference (ΔT) is used as a criterion. However, from the correlation between the weld nugget diameter (L) and the temperature difference (ΔT) or both, Judgment criteria can be set.

  According to the present invention, since it is possible to accurately determine the welding state of the resistance welded portion between the cells, the start lead-acid battery and the electric vehicle are required to have high reliability of the connection portion between the cells from the usage environment where the vibration impact is applied. It is suitable for lead storage batteries for use.

The figure which shows the manufacturing apparatus of the lead acid battery by this invention Diagram showing in-process battery during welding The figure which shows the time change of connected body temperature Diagram showing temperature measurement position The figure which shows correlation with welding nugget width (W) and temperature difference ((DELTA) T).

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Manufacturing apparatus (lead storage battery of this invention) 102 Electrode for electricity supply 103 Power supply device 104 Welding controller 105 Temperature measuring means 106 Pass / fail judgment means 201 Work-in-process battery 202 Battery case 203 Bulkhead 204 Cell chamber 205 Connector 206 Electrode plate group 207 Positive electrode plate 208 Negative electrode plate 209 Separator 210 Shelf part 211 Through-hole 212 Welding nugget 401 Position (electrode for energization is arranged) 402 Temperature measurement position

Claims (4)

The electrode plate group provided with the connection body is stored in the plurality of cell chambers partitioned by the partition wall in the battery case, and the connection body provided in the electrode plate group is provided in the partition wall in the electrode plate group adjacent to each other through the partition wall. In the method of manufacturing a lead-acid battery in which the connecting bodies are pressed against each other through the through-holes, the connecting bodies are pressed with the current-carrying electrodes to contact each other, the welding current is passed between the current-carrying electrodes, and resistance welding is performed between the connected bodies. The temperature (T1) of the connection body before energization is measured, the temperature (T2) of the connection body is measured after a predetermined time after the end of energization, and the temperature difference (T2-T1 ) between these temperatures (T1) and temperature (T2). ) Is compared with a quality criterion determined from the relationship with the weld nugget width (W) measured in advance, and a quality determination of the welded portion is performed. The method for manufacturing a lead-acid battery according to claim 1, wherein the temperature (T1) and the temperature (T2) are measured using a non-contact temperature sensor. A plate group provided with connection bodies is stored in a plurality of cell chambers partitioned by partition walls in the battery case, and in the electrode plate groups adjacent to each other via the partition walls, the connection bodies provided in these electrode plate groups are connected to the partition walls. A lead-acid battery manufacturing apparatus that opposes through the through-holes formed in the electrodes, presses the connection bodies with current-carrying electrodes to bring the connection bodies into contact with each other, energizes a welding current between the current-carrying electrodes, and resistance-welds the connection bodies. , The temperature (T1) of the connection body before energization, the temperature measurement means for measuring the temperature (T2) of the connection body after a predetermined time after the end of energization, and the weld nugget width in which the temperature difference (T2-T1) is measured in advance The manufacturing apparatus of the lead storage battery characterized by including the quality determination means which performs quality determination of a welding part in comparison with the quality determination criteria calculated | required from the relationship with (W) . The lead-acid battery manufacturing apparatus according to claim 3, wherein a non-contact temperature sensor is used as the temperature measuring means.

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