JP4557829B2 - Inspection method of lead acid battery - Google Patents

Description

The present invention relates to a lead-acid battery inspection method, in particular, a lead-acid battery inspection in which a high-voltage pulse is applied between the positive and negative electrodes, and the applied voltage is varied according to the space gap distance between the electrode plates to detect separation of the separator and burrs. It is about the method.

As a process in the process of manufacturing lead-acid batteries for automobiles, a separator is inserted between positive and negative electrodes that are sequentially conveyed through a conveyance line, and a plurality of electrode plates and separators are alternately stacked. An electrode plate group is formed, and this is accommodated in a battery case, and the separator is checked for quality. This inspection detects the presence or absence of a separator or a short circuit, and is performed by applying a high voltage between the positive and negative electrodes.

For example, a voltage is applied between the electrode plates of an uninjected storage battery, and after a predetermined time has elapsed since the start of this voltage application, voltage fluctuations between the electrode plates are detected over a certain period of time. When the magnitude of voltage fluctuation exceeds the threshold value, it is determined that the storage battery is defective (Patent Document 1), or an applied voltage having a high voltage of 1000 to 3000 V and a pulse width of 5 to 20 μs. (Patent Document 2) and the like have been proposed in which an internal short circuit is detected across the cells and added between the positive and negative electrode plates of the electrode plate group.
JP 2002-110217 A Japanese Patent Laid-Open No. 51-16439

However, in the method described in Patent Document 1, since a high voltage is continuously applied between electrode plates when a failure due to separator dropping or electrode plate bending is determined, insulation is performed between the electrode plates by continuously applied voltage. There was a risk of destruction, corona discharge, and opening a hole in a normal separator. In the method of Patent Document 2, only one pulse is generated with a pulse interval of 17 to 20 ms and a pulse width of 20 to 50 μs. In order to prevent the active material from dropping even when there is no separator, In some cases, paper is affixed to the surface of the plate. In this case, since insulation is maintained by the paper, there is a possibility that separation of the separator and internal short-circuit detection may not be accurately performed with one pulse.

Under such a background, it is possible to easily and accurately detect the separation of the separator between the positive and negative electrode plates, and judge the quality of the electrode plate group structure with high reliability. It is desired to provide a method for inspecting a lead storage battery that can determine the presence or absence of an internal short circuit by detecting the occurrence of this.

In the present invention, a plurality of positive / negative electrode plates are alternately stacked via separators, and a group unit or opposed to each other via strap portions of positive / negative electrode plate groups facing each other. In an inspection method in which a high voltage pulse is sequentially applied to each pair of positive and negative plates, the high voltage pulse is applied according to a spatial gap distance between a pair of opposite positive and negative plates, an applied voltage, a pulse interval, and a pulse width. Further, the number of pulses is varied, the applied voltage is set to be equal to or higher than the voltage at which dielectric breakdown occurs, the pulse interval is set to 5 to 40 ms, the pulse width is set to 1 to 20 μs, and the number of pulses is expressed by the following formula (Formula 1). It is calculated by using the correlation with the applied voltage, the pulse interval, and the pulse width, and detects the separation of the separator and burrs.

Further, the number of pulses is obtained by, characterized in that calculated using correlation value obtained by dividing the pulse interval applied voltage and pulse width estimation.

In the present invention, the applied voltage, the pulse interval, the pulse width, and the number of pulses are varied by changing the gap distance (hereinafter referred to as the space gap distance) when a pair of opposing positive and negative electrode plates are removed. It detects missing or burrs. When the distance between the electrode plates is constant, the occurrence of corona discharge is substantially determined by the applied voltage, the applied time (pulse interval, pulse width), and the number of pulses. Therefore, there is a paper or the like (hereinafter referred to as insulating paper or the like) on which the separator is removed and the applied voltage, application time (pulse interval, pulse width) and number of pulses that can cause corona discharge depending on the space gap distance are adhered to the electrode plate surface. By setting a value that does not make an erroneous determination (a value that causes corona discharge) even in some cases, it is possible to accurately determine whether the separator is removed and there is insulating paper or the like.

The corona discharge is a region where a local discharge occurs when a high voltage is applied and a region of a strong electric field is localized. The corona discharge referred to in the present invention is a case where corona discharge occurs in the absence of a separator (hereinafter referred to as conduction), and a case where corona discharge due to penetration of the separator occurs due to excessive application of voltage for a long time in the presence of the separator. (Hereinafter referred to as dielectric breakdown).

By using the lead storage battery inspection method according to the present invention, it is possible to easily detect the separation of the separator between the electrode plates with high accuracy, and also to detect the burr of the electrode plate. Can be provided.

An embodiment of the present invention will be described with reference to FIGS.

The method for inspecting a lead storage battery of the present invention inserts an electrode plate group formed by alternately laminating positive and negative electrode plates with separators into a battery case, and injects positive and negative electrodes before injecting an electrolyte solution. Separation of separators and burrs are accurately detected by applying a high voltage pulse in order to each group unit or each pair of opposing positive and negative electrode plates via the strap part of the negative electrode plate group. Is. FIG. 1 is an explanatory view showing an embodiment of the present invention, and FIG. 2 is a chart when the inspection method for the product of the present invention is used.

FIG. 1 is an explanatory view showing an embodiment of the present invention, where 1 is a high voltage pulse generator, 11 is a probe for measurement, 2 is a laminate of positive plates 21 and negative plates 22 alternately with separators 23 interposed therebetween. The electrode plate groups 3a and 3b configured as described above are strap portions in which the ears 24 of the positive and negative electrode plate groups are connected by a cast-on-strap method (hereinafter referred to as COS method).

As shown in FIG. 1, after the electrode plate group 2 constituted by alternately stacking the positive electrode plates 21 and the negative electrode plates 22 via the separators 23 is joined to the respective ear portions 24 of the positive and negative electrode plates by the COS method. The battery is stored in a battery case (not shown), and the separator 23 is inspected for leakage before the electrolyte is injected. A high voltage pulse is generated by the pulse generator 1 and applied to the strap portions 3a and 3b of the opposing positive and negative electrode plate groups via the probe 11 in groups. Then, a voltage pulse of high voltage is applied, and the pass / fail determination of the presence or absence of separators and burrs is detected from the current value. After the current value is detected, those determined to be non-defective are conveyed to the next process, and those determined to be defective are removed from the process. Incidentally, the strap portion 3a of the positive and negative voltage pulses which faces have been applied in the group unit through 3b, positive by sequentially contacting the probe 11 to the positive and negative electrode plates of each one of opposed respectively -You may make it perform the quality determination between a pair of electrode plates which consist of one piece of each negative electrode.

Whether or not the separator is removed is determined by whether or not conduction has occurred between the positive and negative electrodes. Whether or not conduction has occurred is determined by a change in current value using a current measuring device (not shown). Since conduction is determined substantially by the applied voltage, the applied time (pulse interval, pulse width), and the number of pulses, the applied voltage, applied time (pulse interval, pulse width) and pulse using, for example, a high voltage pulse generator. It is possible to determine whether the separator is missing or not by changing the current value with a constant number.

When the separator is in a normal state (non-defective product), the insulation between the positive and negative electrodes is maintained by the separator, no conduction occurs and the current value does not change. In the present invention, conduction occurs when the separator comes off. When the separator is missing (defective product), conduction occurs and the current value changes, so that the separator can be accurately detected. Insulation may be maintained by insulating paper or the like attached to the surface of the electrode plate when the separator is removed, but in the present invention, when the separator is removed due to the space gap distance, the separator is removed and the surface of the electrode plate is removed. Since there is a value that does not make an erroneous determination (a value that conducts) even when there is an attached insulating paper or the like, it is possible to accurately determine whether or not the separator is removed and there is insulating paper or the like.

In addition, the inspection for the presence or absence of burrs can be performed at the same time in the same manner as the determination of whether or not the separator is missing. When there is no burrs, conduction does not occur and there is no change in the current value. Since continuity occurs and the current value changes, the presence or absence of burrs can be easily determined. In addition, even if the separator is in a normal state, if a burr is generated, dielectric breakdown occurs and it is determined as a defective product and is removed from the process.

FIG. 2 shows an inspection chart of the present invention in which a voltage pulse is applied. For example, when the applied voltage (v) is applied with a pulse width of time (t1), the conduction current (presence / absence of separator) is detected at time (t2) after voltage application, and the pass / fail judgment of separator separation is performed. During the time (t3), the presence or absence of conduction current is confirmed. When performing the pass / fail determination, if there is no fluctuation in the current value, it is judged as a non-defective product and conveyed to the next process, but if there is a fluctuation in the current value, it is judged as a defective product due to a separator missing or an internal short circuit due to burrs. Since the time during which the high voltage is applied is limited to a time as extremely short as t1, there is no fear of making a hole in the separator by corona discharge. In the example shown in the figure, a conduction current flows according to the applied voltage, and the pass / fail judgment signal is turned ON to determine that the failure is detected. After that, an output stop signal is output to prepare for the next voltage application.

(Test 1)
The strap part is welded to the electrode plate group formed by pasting paper on the surfaces of the positive electrode plate and the negative electrode plate manufactured by a known method and alternately laminated via a separator using a known COS method, and then A lead storage battery (semi-finished product) was prepared before the electrode plate group was housed in the battery case and the battery case was covered. Then, the dielectric breakdown was inspected before the electrolyte solution was injected. In the dielectric breakdown test, a high voltage pulse was generated by a pulse voltage generator and applied to the strap portions of the opposing positive and negative electrode plate groups in groups via a probe. At this time, when inserted into the battery case, the thickness of the separator disposed between the positive and negative plates of the electrode plate group is set to 0.35 mm, the applied voltage is changed from 1.2 to 2.5 kV, and the current value is measured. Then, whether or not dielectric breakdown occurs was measured. The applied pulse width was 300 μs, and only one pulse was applied.
As a result, dielectric breakdown occurred at all voltages despite the fact that the separator was a non-defective product.

(Test 2)
Next, use the same lead-acid battery (semi-finished product) used in Test 1, prepare a defective product with the separator removed, and a good product with no separator removed, and apply a pulse voltage of 2 μs at an interval of 20 ms. 15 pulses were applied. As a result, up to 1.3 kV, a defective product without a separator was judged not good because it did not conduct, and at 1.4 kV or more, a separator that was normally arranged was judged as defective due to dielectric breakdown.

(Test 3)
Furthermore, in Test 2, as a result of applying 3 pulses of a pulse width of 2 μs at an interval of 20 ms as a pulse voltage to be applied, a defective product without a separator is erroneously determined as a non-defective product at a voltage of 1.5 kV or less, and is 1.7 kV. With the above voltage, the separator with the separator arranged correctly was mistakenly judged as defective. However, when the voltage is 1.6 kV, the separator without the separator is judged as defective, and the separator with the separator is judged as non-defective. The determination was good.

(Test 4)
Based on the above test results, when the lead-acid battery (semi-finished product) used in Test 1 was stored in the battery case with various separator thicknesses, the distance between the positive and negative electrode plates was 0.15, 0.275, 0. .325, 0.35, 0.4, 0.45 mm, and a defective product with the separator removed. The applied voltage was changed from 1.0 to 1.8 kV, and the pulse voltage was changed in the same manner as in Test 3. Three pulses of a voltage having a pulse width of 2 μs were applied at intervals of 20 ms, and the conducting voltage was measured. The results are shown in Table 1.

  As shown in Table 1, it can be seen that the voltage at which conduction occurs varies depending on the space gap distance between the positive and negative electrode plates (thickness of the separator in the battery case). As the spatial gap distance increases, the voltage at which conduction occurs increases, and conversely, as the spatial gap distance decreases, the voltage at which conduction occurs. When the spatial gap distance was 0.35 mm, conduction did not occur at a voltage lower than 1.6 kV, and conduction occurred at a voltage higher than 1.6 kV. For example, when a separator is used that holds a gap between the positive and negative electrode plates of 0.35 mm when the electrode plate group is stored in the battery case, the space gap distance when the separator is removed is about 0.35 mm, which is detected. When it does, it turns out that the applied voltage of 1.6V is good. That is, it is sufficient to apply a voltage value higher than the voltage at which conduction occurs at the spatial gap distance. Hereinafter, tests were conducted based on the relationship between the voltage at which conduction occurs and the space gap distance shown in Table 1.

(Test 5)
Next, a lead-acid battery (semi-finished product) was produced in the same manner as in Test 1, and the pulse intervals in Test 3 were set to 5 to 40 ms and 5 ms intervals using the voltages at which the corresponding conduction occurs at the spatial gap distances shown in Table 1, respectively. If the pulse interval is short as a result of the change, the normal one with the separator is mistakenly judged as a defective product due to dielectric breakdown, and if the pulse interval is long, the one with the separator removed is not conductive and is regarded as a good product. There was a tendency to judge.

(Test 6)
Next, a lead-acid battery (semi-finished product) was prepared in the same manner as in Test 1, and the pulse with the pulse interval in Test 3 was kept constant at 20 ms using the voltage at which the corresponding conduction occurs at the spatial gap distance shown in Table 1. As a result of changing the width to 1, 2, 3, 5, 10, 20 μs, respectively, when the pulse width was increased, a good product with a separator tended to be erroneously determined as a defective product due to dielectric breakdown.

(Test 7)
Next, a lead-acid battery (semi-finished product) was prepared in the same manner as in Test 1, and the voltage at which the corresponding conduction occurs at the spatial gap distance shown in Table 1 was used, and the pulse width in Test 3 was 2 μs and the pulse interval was 20 ms. As a result of changing the number of applied pulses to 1 to 15 times, when the number of pulses was increased, a good product with a separator tended to be erroneously determined as a defective product due to dielectric breakdown.

From tests 1 to 7, it was found that the number of pulses correlates with the applied voltage, the pulse interval, and the pulse width when using voltages at which the corresponding conduction occurs at the spatial gap distances shown in Table 1.
According to an empirical rule, the equation is approximately expressed by the following (Equation 1).

(Equation 1)
However, the constant K is 1.0 / mm, and the dielectric breakdown electric field is the value of air, which is 3.35 kV / mm.

In the same spatial gap distance, the number of pulses that can be detected without error determination increases as the pulse interval increases in tests 1 to 7, and decreases as the applied voltage increases and the pulse width increases. From this correlation, it is possible to easily estimate and determine how many pulses can be detected without erroneous determination. For example, when the spatial gap distance is 0.35 mm, the applied voltage is 1.6 kV, the pulse interval is 20 ms, and the pulse width is 2 μs, the number of pulses is 1.7 to 3.7, and the number of possible pulses is approximately 2 to 4. By selecting an appropriate value in the range, it was possible to detect without misjudgment.

When a lead-acid battery (semi-finished product) is prepared in the same manner as in Test 1 and before applying the electrolyte, using a pulse generator with an applied voltage of 1.6 kV and a pulse interval of 20 ms and a pulse width of 2 μs (Equation 1) The number of pulses was three. A voltage pulse was applied in groups via positive and negative strap portions facing each other, and the quality of 100 electrode groups was determined. The space gap distance between the positive and negative electrode plates was 0.35 mm.

(Comparative Example 1)
The quality of the electrode plate group was determined in the same manner as in Example 1 except that the number of pulses was 15.
(Comparative Example 2)
The quality of the electrode plate group was determined in the same manner as in Example 1 except that the pulse width was 300 μs continuous and the number of pulses was applied only once.

As in the first embodiment of the present invention, when the applied voltage is 1.6 kV, the pulse interval is 20 ms, the pulse width is 2 μs, and the number of pulses is 3 times, the pass / fail judgment can be made accurately, and the misjudgment among the 100 electrode groups. There was nothing to do. However, in Comparative Example 1, 3 sets of non-defective products out of 100 sets of electrode plates were erroneously determined. Further, in the case of continuous application as in Comparative Example 2, more than half of the 100 electrode plate groups were erroneously determined.

As described above, by using (Equation 1) to define the applied voltage, pulse interval, pulse width, and number of pulses according to the spatial gap distance, it is possible to easily and accurately detect the separation of the separator between the positive and negative electrodes. Therefore, the quality of the electrode group can be judged with high reliability.

Explanatory drawing which shows the 1st Embodiment of this invention. The chart which shows this invention embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High voltage generator 11 Probe 2 Electrode plate group 21 Positive electrode plate 22 Negative electrode plate 23 Separator 24 Ear | edge part 3a Strap part 3b Strap part

Claims (2)

A group unit or a positive / negative electrode plate facing each other via a strap part of a positive / negative electrode plate group facing each other in a group of positive and negative electrode plates formed by alternately laminating a plurality of positive / negative electrode plates via separators In the inspection method in which high voltage pulses are sequentially applied to each pair, the high voltage pulses are determined by applying the applied voltage, pulse interval, pulse width, and number of pulses according to the space gap distance between the pair of positive and negative plates facing each other. The applied voltage is set to be equal to or higher than the voltage at which dielectric breakdown occurs, the pulse interval is set to 5 to 40 ms, the pulse width is set to 1 to 20 μs, and the number of pulses is expressed by the following formula 1, the applied voltage, the pulse interval, and the pulse A method for inspecting a lead-acid battery, characterized in that it is calculated using a correlation with the width and detects a separator missing or a burr.
(Equation 1)
However, the constant K is 1.0 / mm, and the dielectric breakdown electric field is the value of air, which is 3.35 kV / mm. 2. The inspection method for a lead-acid battery according to claim 1, wherein the number of pulses is calculated and estimated using a correlation between a value obtained by dividing a pulse interval by an applied voltage and a pulse width.