Electric method of accumulator batteries quality control

FIELD: electricity, electric equipment.

SUBSTANCE: invention is related to electric equipment and may be used in production of accumulators and accumulator batteries, in particular, lead-acid accumulator batteries. During electric monitoring of accumulator or accumulator batteries with electrolyte quality, which is performed on completion of last technological manufacturing operation in the time limits (τ₁-τ₂), which depends on the type of items and technology of their manufacturing, with temperature of electrolyte in items within the interval (T₁-T₂), which depends on the type of items, the process of discharge lasts at least 3 sec and not more than 30 sec, the value of discharge current is maintained equal to I_n for every nominal type of item during the full process of discharge, voltage drop on the outputs U₀ is measured before the discharge start, voltage drop at outputs U₁ is measured in the moment t₁ of discharge process, voltage drop at outputs U₂ is measured in the moment t₂ of discharge process, voltage drop at outputs u_e is measured in the moment t_e in the end of discharge, value ΔU is calculated in equal to difference (U₁-U₂), values U₀, u_e, ΔU are compared with control values U_{0, control}> U_{e, control}, Δu_control for every type of items and on the basis of such comparison the decision is made on the quality of items, at that items are considered high quality if U₀ lies in the range of values U_0,control> u_e more or equal to u_e,control, ΔU less or equal to ΔU_control.

EFFECT: provides reliable monitoring of accumulator batteries quality.

1 dwg

The invention relates to the electrical industry, namely the production of batteries and rechargeable batteries.

In modern akkumulatoren on automatic lines for the production of batteries and rechargeable batteries are widely used electrical methods of quality control of products. Solid audited as a separate electrode blocks of batteries and accumulators and batteries, both at the stage of Assembly, automated Assembly lines, when items are dry, without electrolyte, and after formation, when the product is already with the electrolyte. Selective electrical method of controlling the quality of products is used for periodic testing of manufactured batteries and rechargeable batteries, as dry-charged, without electrolyte, and filled with electrolyte and is ready for operation. These procedures have an important place in the production cycle for the reason that enable you to diagnose and time to eliminate the defects, thereby ensuring the high quality of its products.

The defects that are most often encountered include the following:

- defects separators (through micro pores in the separator, the hole in the separator, puncture the separator crumb active mass);

- excessive or insufficient compression is aparatorul between the electrodes;

- short circuit of the electrodes (due to contact between the metal chip that was formed during the Stripping of molded fin; due wiernosci electrodes);

- inversion of block electrodes (incorrect polarity) due to operator error during installation;

- defects of the electrodes (gap veins, damage frame damage to the eye);

- defects pole bridges (shell, cuts);

- defects inter-element connections ("cold" welding, sinks, cracks);

- poor adhesion of the active mass to the current leads;

the passivation of the electrodes

These defects or immediately make and batteries unusable or significantly reduce their specifications and take them down during further operation.

In the scientific and patent literature suggested many electrical methods of quality control of batteries and rechargeable batteries, from the simplest, consisting in determining the internal resistance of the products with an ohmmeter, to the most complex, requiring the use of expensive equipment, for example, methods based on impedance spectroscopy.

We will not analyze impedance test methodology, and consider simpler and more accessible to the domestic production of electric means control the, and only those that allow you to apply a solid (100%) control of products within a fairly short period of time.

Known electrical method of controlling the quality of the batteries in places of contact between elements of compounds, consisting in the fact that with the help of a charged capacitor Bank through the tested weld skips the current pulse, the power is sufficient to heat the place of the weld, commonly used to measure the discharge time of capacitor Bank from the beginning of the discharge to a predetermined final value of the voltage drop across the weld for a given type of battery, and the value of this discharge time is judged on the quality of welded joints [A.S. USSR №1266424, IPC⁴H01M 2/22, 10/42, UK 11/10 declared 06.12.84].

The method allows efficient determination of welding defects using the phenomenon of significant heating of the weld from the noise current pulse, taking into account the dependence of the ohmic resistance of the weld quality welding. Such verification is reasonable at the stage of Assembly of the battery after welding it interelement connections.

The main disadvantage of this method is the fact that it cannot be used for quality control electrode battery packs and batteries in General.

Known the simplest way to control quality is STV lead-acid batteries with a DC voltmeter accuracy class not less than 1.5 internal resistance of not less than 300 Ohms/GOST 8711 and DC source voltage of the 2nd Century There is no short circuit in the electrode block is fixed by the absence of arrow deflection of the voltmeter connected to the terminals of the battery in series with the constant current source (2 volt). Similarly, the absence of conductivity between the electrodes is fixed by the absence of arrow deflection of the voltmeter connected to the terminals of the battery. This method was applied in the domestic military industry and allowed us to test only dry-charged battery (without electrolyte) [GOST In 22759-84].

The method allows to determine the defects that creates conductivity and short circuit in the electrode block.

The disadvantages of this method include the fact that it is not possible to verify lead-acid battery with electrolyte (in exceptional issue which goes modern akkumulatoren), and the fact that the practice showed low reliability of this method. In addition, this method cannot be applied for quality control interelement connections at the battery.

Known, common on automatic Assembly lines, solid electrical method of controlling the quality of batteries and rechargeable batteries [SOVEMA S.p.A. http://www.sovema.it] is that on the pole bridges electrode block from the external source of electrical energy serves voltage is s (constant or variable) fixed level (500 or 1000), and then in the resulting circuit, in which the electrode blocks are load, measure the amount of current. If the current exceeds the reference mark (the so-called cut-off current), this indicates the presence of a defect and the electrode block is discarded, and then you replace it with a serviceable unit.

This method of testing can reduce the number of defective products after the end of the Assembly.

To the main disadvantage of this method is that it is not possible to check the batteries and battery with electrolyte, i.e. products, ready for use. In addition, as supplied to the electrode block voltage cannot exceed 1.2 kV (breakdown voltage separator), it is not determined an important defect, as the through micropores in the separator. Another significant omission is the fact that this method is ineffective for welding quality control inter-element connections, and therefore the control of welding is carried out in other ways.

As the modernization of the above test, you can examine the electrical method of controlling the quality of batteries and rechargeable batteries, according to which on auto Assembly lines of the electrode blocks of the batteries are subjected to several consecutive cycles of test, and at first icle measure and record the conductivity of the electrode Assembly at a voltage of 5-30 Within 0.005 to 0.3 s, on the second cycle is its conductivity when the voltage 300-600 for a period of from 0.005 to 0.3 s, on the second cycle - conduction when the voltage 1000-1700 To within 0.005 to 0.1 s and on the fourth cycle - conduction when the voltage 2000-4000 Within 0,002-0,005 C. To determine the degree of hydration of the electrode plates of dry-charged batteries are pre-measured EMF at their pole conclusions in the course of 0.005 to 0.3 with [the Patent of Ukraineïnor No. 51163, IPC⁷NM 10/04, 10/42, G01R 31/36. Publ. 15.02.2005, bull. No. 2]. All measured values are compared with reference values that serve as a criterion.

The advantages of this method of validation is to minimize defective products by the end of the Assembly.

The main disadvantage of this method is the fact that it is not possible to check ready to use batteries and rechargeable batteries with electrolyte. In addition, this method cannot be used when testing the quality of welding interelement connections.

Known electrical method of quality control flooded electrolyte lead-acid storage batteries, which consists in the fact that the batteries are subjected to intermittent discharge current 9C₂₀And (but not higher than 1700). Intermittent discharge includes four periods, consisting of alternating discharge duration (5+1) and pause duration (10+1), then measures the I end voltage at the battery terminals, performed visual inspection of pole terminals, done a full battery charge and subsequent discharge starter current when the temperature of the electrolyte (25±5)°C. the Requirements of this method checks the following: the final voltage at the battery terminals after intermittent discharge should not be below 6.0; pole battery terminals must not be damaged; in the subsequent starting of the discharge voltage on the battery terminals must be at least 9.0 In on the 30th second of the discharge, and the duration of discharge (to a final voltage of 6.0 In) not less than 150 [GOST 959-91].

This test allows to reject ready-to-use products for the whole set of possible defects, but primarily on the quality of live parts.

The disadvantages of this method is that it involves a long procedure, considering the total time intermittent discharge and subsequent full charge and starter battery. In addition, this method of quality control recognizes the destructive and therefore can only be applied selectively (according to GOST 959-91 such audit is conducted on a sample of batteries once every six months) for periodic testing. Another disadvantage of this method is that it is chosen only for lead-acid batteries.

Although the above electric way to the of ntrolle refers to a sample, it is interesting for us as a close substitute. Targeted modernization of this method can lead to a significant shortening of the time of the test and translation test in the group of non-destructive control methods that will allow to use it for continuous quality control of products.

As a prototype we used an electrical method of controlling the quality of batteries and rechargeable batteries with electrolyte, consisting in the fact that the product is subjected to discharge, before which, and during which at fixed time points (0, t₁, t₂=2t₁0.3-0.5 s) measure the voltage drop on the findings of a product, calculate the value of ΔU represents the change in the voltage on the conclusions at different points in time of the discharge process, which allows to check the quality of the product and to evaluate its electrical parameters, according to the electrical circuit of the battery [RF Patent №2101806, IPC⁶NM 10/48, G01R 31/36. Publ. 10.01.1998, bull. No. 1].

The advantages of this method of testing is that it allows us to estimate the electrical parameters of the product within the estimated simplest electric circuit the battery, if the battery has no defects. In addition, this method of control can be applied as a solid.

The disadvantages of the prototype is tositsa, this control method has no restrictions on timing and temperature of the electrolyte in the batteries. The fact that at the end of the latest technological operations of manufacturing, for example, forming, are some transients in batteries: reduced polarization at the electrodes, is the cooling of the electrolyte, the electrodes and the electrolyte between the electrodes are exempt from gas bubbles resulting from electrochemical side reactions. All this greatly affects the control parameters of the product, in particular on the electrical resistance, and complicates the interpretation of the results. In addition, most chemical current sources voltage change (ΔU) on the terminals of the battery in the first fraction of a second (0.3 to 0.5) is very unstable value, which depends on many factors and is not always correlated with the presence of defects. As a result of applying this method of quality control in production may result in frequent cases zabrakovanie quality products or, on the contrary, receipts to consumers of products with defects. In addition, in the case of defect is calculated according to the results of the discharge process the electrical parameters of the battery is already not reflect the real situation, and are dummy variables.

The basis from which retene on the task of improving the reliability of the electrical method of controlling the quality of batteries and rechargeable batteries that would minimize the possibility of income to consumers of defective products or incorrect zabrakovanie quality products.

The problem is solved in that in an electric way of controlling the quality of batteries and rechargeable batteries (products) with the electrolyte, consisting in the fact that the product is subjected to discharge, before which, and during which at fixed time points to measure the voltage drop on the findings of a product, calculate the value of ΔU represents the change in the voltage on the conclusions at different points in time of the discharge, according to the invention, the control method is carried out after the end of the last manufacturing operations manufacturing time (τ₁-τ₂), depending on the type of products and their manufacturing techniques, when the temperature of the electrolyte in the products in the range (T₁-T₂), depending on the type of products, the discharge lasts at least 3 and not more than 30, the value of I_nthe discharge current measured in And support equal (8-12)₂₀during the whole process of discharge, where C₂₀numerically equal to the nominal capacity of the battery in ampere·hours, measure the voltage drop U₀on the findings before discharge, measure the voltage drop U₁the conclusions at time t_{1 process discharge, measure the voltage drop U2the conclusions at time t2process discharge, measure the voltage drop Utothe conclusions at time ttothe end of discharge, calculate the value of ΔU, equal to the difference (U1-U2), compare the values U0Utothat ΔU with the control values U0,counterUto the rearthat ΔUcounterfor each type of product and on the basis of such comparison, decide on product quality, thus consider quality products, for which U0belongs to the interval U0,counterUtogreater than or equal to Uto the rearthat ΔU is less than or equal to ΔUcounter.}

Reveal the essence of the claimed technical solution. Electrical method of controlling the quality of the batteries with the electrolyte must be carried out in identical conditions, the same for all products of the same type, but depends on the technology of their production. Therefore, depending on the technology installed limiting condition at time of testing: the test is conducted in a certain period of time (τ₁-τ₂) after the last manufacturing operations manufacturing - after forming. Depending on the technology of formation: medium size forming current, time, shaped who I am, the intensity of the heat sink (cooling devices), and other factors is set to a specific value of the interval (τ₁-τ₂). The lower bound of the specified interval is chosen so that by the time managed to go through major transitions in batteries: the decrease in polarization at the electrodes after the current is switched off, the release of the electrodes and the electrolyte between the electrodes from the gas bubbles resulting from electrochemical side reactions. The upper boundary of the specified interval is chosen from considerations limit the duration of the technological cycle in order to achieve high productivity.

Depending on the technology installed limiting condition and temperature of the electrolyte in the products. Because after the formation is the cooling of the electrolyte and the change in electrical conductivity in the battery is given an interval of temperature (T₁-T₂). At higher temperatures the electrical conductivity increases sharply, and at lower - decreases dramatically, which significantly affects the electrical parameters of products and displays them beyond identical conditions of the test. For each type of battery has its own optimal temperature range.

The duration of the discharge is chosen in the range from 3 to 30 s, which, with the etoy magnitude of the discharge current I _nallows for all known types of batteries and rechargeable batteries to test quickly and at the same time to ensure the sustainability of change of voltage on the findings. If the duration of the discharge is less than 3, then we get into a region of unstable voltage on the findings of the product. If the duration of the discharge of more than 30, taking into account the magnitude of the discharge current I_nthat in such tests is chosen high enough, we subject the product to an appreciable loss of electrical capacity. But this entails the need for additional technological operations of charging, which is disadvantageous in the production environment.

The above limiting conditions at time of test, the temperature of the electrolyte in the battery and the duration of discharge are selected empirically.

After we explained the necessity of the limiting conditions of the test, consider the control parameters of the test. Within the same type of products, for example, lead-acid, Nickel-cadmium or other, but depending on liposomial (voltage, capacity, discharge current under standard conditions), selected values of I_nthe discharge current in this test. Typically, these values are quite high (higher than in any other electrical tests). The higher the capacity or rasra the hydrated current under standard conditions, the higher I_nthe discharge current at the stated test. This dependence is usually close to linear dependence and is chosen empirically. Selection is carried out so that the product was identical electrical conditions and showed identical electrical parameters, in particular, the voltage on the findings.

The voltage drop on the conclusions U₀that measured before the start of the discharge is equal to the value of the open circuit voltage. This value depends on the type and liposomal product and varies in a narrow range. For each type of product set its interval U_0,counter. If U₀below the lower limit of the specified interval, then the product or nezarazeno or has a defect: short circuit, high self-discharge, etc. If U₀the upper limit of the specified interval, there is the following possible defects that need to be addressed: unacceptably high concentration of electrolyte in the battery, the electrolyte impurities. The range of values of U_0,counterestablished empirically.

The voltage drop on the conclusions U_tothat is measured at time t_tothe end of discharge, characterizes the ability of a product to withstand the discharge currents of high magnitude and, in General, characterizes the quality of the batteries and ccumulating batteries. This is because at the discharge of the batteries or rechargeable batteries, the voltage on their findings gradually decreases. The lower the U-value of_tothe following electrical parameters of the product. Therefore, set the reference value of the voltage U_{to the rear}at the end of discharge. If you checked U_togreater than or equal to U_{to the rear}the product has successfully passed the test, if U_toless U_{to the rear}then the product is defective. The value of U_to,constselected empirically.

Now consider the value of ΔU. the Necessity of introducing this value is dictated by the following considerations. Discharge curve of the battery or batteries in General consists of three sections: the initial phase of rapid decrease in the voltage on the findings; the middle portion of the smooth, almost linear decrease of the voltage on the pins; end plot nonlinear rapid decrease in the voltage on the findings. The initial segment, as noted above, characterized by instability of the magnitude of the voltage change. A similar property is inherent in the final section of the discharge curve. Therefore, if control is to be limited only by the measurement values U_toit does not provide reliable results. Experience testing confirms that the value of U_toindeed h is always correlated with the presence of defects. At this value appreciably affected by the flow discharge at the initial and final stages. Even if the duration of the control discharge to choose such that U_towill be measured at the middle section bit curve, still to this value will influence the results of the initial stage of discharge. Therefore, the largest U_toyou can install only gross defects. In this regard, and enter a value of ΔU, which is defined as the voltage difference (U₁-U₂), measured in the middle part bit of the curve at time t₁and t₂the process of discharge. In the middle part bit of the curve smooth, almost linear decrease of the voltage on the conclusions does not depend on the randomness of the initial or final stage of discharge and allows you to establish a reliable correlation with the absence or presence of defects in the product. The sooner there is a change in voltage ΔU in the middle part of the curve (i.e. the higher the value ΔU), the less electrical parameters of the product. If ΔU becomes larger than a certain reference value ΔU_0,counterit means that the battery or the battery is defective. If ΔU is less than or equal to ΔU_counterthat means the product quality. It is obvious that the value of ΔU_counterset the flows empirically.

According to the authors of the proposed information essential features that characterize the essence of the invention, is not known in this branch of technology.

The proposed solution can be used for continuous quality control in the production of batteries and rechargeable batteries, particularly lead-acid types.

The drawing shows a General view of the discharge curve of the battery or rechargeable battery.

The voltage on the findings of a U₀the open circuit voltage, which is measured before discharge. The voltage on the findings of a U₁measured at time t₁in the middle part bit of a curve - plot smoother (almost linear) decrease of voltage during the discharge of the product. The voltage on the findings of a U₂measured at time t₂also in the middle part bit curve. The voltage on the findings of a U_tomeasured at time t_tothe end of discharge.

Proposed invention the method is carried out in the following way. In a certain time interval (τ₁-τ₂after the latest technological operations of manufacturing products are tested, with controlled, so testing was limited products, with the temperature of the electrolyte within (T₁-T₂). On practiceto means, the program of formation and management of cooling is built in such a way that the product after the formation had a temperature within the specified range (T₁-T₂). Then the materials are received at the installation of the discharge current of large magnitude, while immediately before discharge measure the voltage on the findings of a U₀and compare it with U_0,counter. If the value of U₀included in the interval U_0,counterthe product is subjected to discharge; if not included, the product is rejected and, depending on the specific case, eliminate defects (dataresult or produce a change of the electrolyte) or reject completely. The magnitude of the discharge current I_nset according to the technical documentation for this liposomial manufactured products. The duration of the discharge is maintained within the limits established in the technical documentation, but not going beyond the limits set out in the claims (3-30). During the discharge measured the voltage at the terminals of the battery or battery pack: U₁measured at time t₁U₂measured at time t₂U_tomeasured at time t_to. Automatically by the unit of the discharge current of large magnitude calculated value ΔU is (U₁-U₂), and compare U_towith U_{to the rear}a ΔU CPA is Nivat with Δ U_counter. If both the condition that U_togreater than or equal to U_{to the rear}and ΔU is less than or equal to ΔU_counterthen consider the product quality and sent to the warehouse of finished products. Otherwise, the product is rejected and, depending on the specific case, eliminate defects or reject completely.

We give a concrete example for the most common products - starter lead-acid batteries with a nominal voltage of 12 Century After the formation of the water-cooled batteries are the adjustment of electrolyte level on a special machine adjustments, tightening of the tubes, washing and drying, and then proceed to install the test current of large magnitude. Limiting conditions for control are as follows: τ₁=0,1 h τ₂=5 h, T₁=15°S, T₂=36°C. Practically, this means that during the first 5 h after formation of the battery should be tested, the temperature of the electrolyte should be no higher than 36°C. As in the General case, for a lead-acid battery program of formation and control of the temperature of cooling water is constructed in such a way that the batteries after the formation had a temperature within the prescribed limits. If the battery is too g is hot, it is compulsory accelerated cooling in forming a bath of cooling water. The temperature in the shop and the cooling water temperature is automatically provide the temperature of the electrolyte in the battery is not lower than 15°C. Limiting condition for the duration of the control digit is automatically provided by the software installation of the discharge current of large magnitude: the duration of the discharge set within (6,0-8,0), depending on the design characteristics of the battery.

The reference value of the open circuit voltage for lead-acid batteries is U_0,counter=(12,74-13,10) C. This interval is injected into the setup of the discharge current of large magnitude. Measurement U₀produce before discharge; installation automatically compares U₀and U_0,counterand if the value of U₀included in the interval U_0,counter, the battery is subjected to discharge; if not included, then the battery excluded and, depending on the specific case, eliminate defects or reject completely. To disposable defects include: incomplete charging of the battery or the presence of harmful impurities (leading to accelerated self-discharge)when the open circuit voltage is too low; the increased density of the electrolyte or the presence of impurities in the electrolyte, when supragenerational circuit is too high. Eliminates such defects that the battery dataresult or produce a change of the electrolyte. In other cases: short circuit, irreversible sulfation, the discharge through the damaged walls of the monoblock battery - reject completely.

The discharge of the battery currents of large magnitude I_ndepending on liposomial batteries and components value in the range (8-12)₂₀And where₂₀numerically equal to the nominal battery capacity in ampere·hours. For example, the values of I_nthe discharge current is: (550-610) And battery type 6ST-AS, (620-680) And battery type 6ST-60AZ, (810-850) And battery type 6ST-AS, (1350-1540) And battery type 6ST-AS, (1600-2090) And battery type 6ST-AS, depending on the design characteristics of the battery. When installing produce battery discharge, automatically measured control values U₁and U₂in moments discharge t₁=(3.5 to 4.0) and t₂=(6,0-8,0) with (depending on the design features of the product), and t₂coincides with the time t_tothe end of the discharge (t₂=t_to), and hence U₂=U_to. It should be noted that, unlike the prototype, the inventive method of quality control first measurement voltage on the conclusions made after 3.5 seconds of discharge (t₁=(3,5-4,0) (C), when the change of voltage in the waters becomes sustainable value reliably correlated with the presence or absence of defects in the battery. Statistics tests showed that the starter lead-acid batteries in the first 1-2 with discharge currents of large magnitude change in the voltage on the findings is unsustainable (initial segment bit curve), so the voltage U₁measured during the first 2 seconds of discharge, reliably indicates the quality of the battery, respectively, and the value of ΔU will also provide unreliable evidence about the quality. Selection of values of t₂=t_to=(6,0-8,0) due to the fact that lead-acid batteries, discharge currents of large magnitude, at this point, the voltage on the findings more smoothly, almost linearly decreases (the middle portion of the discharge curve). This allows to obtain reliable criterion for the quality of the batteries, especially the largest ΔU. so, the unit automatically calculates the amount of ΔU and compares the values U_toand ΔU with the control values U_{to the rear}and ΔU_counter. The control parameter values for lead-acid starter batteries are U_{to the rear}=(8,00-9,50), depending on the design characteristics of the battery, ΔU_counter=0,10 Century If at the same time the condition that U_togreater than or equal to U_{to the rear}, and ΔU is less than or equal to ΔU_counterthen the battery is considered qualitative and sent to the warehouse of finished products. Otherwise, the battery excluded and, depending on the specific case, eliminate defects or reject completely.

Successfully tested the batteries are labeled, Packed on pallets and sent to the warehouse of finished products.

Verification of the declared method in the factory has confirmed its high efficiency.

Electrical method of controlling the quality of batteries and rechargeable batteries (products) with the electrolyte, consisting in the fact that the product is subjected to discharge, before which, and during which at fixed time points to measure the voltage drop on the findings of a product, calculate the value of ΔU represents the change in the voltage on the conclusions at different points in time of the discharge, characterized in that the control method is carried out after the end of the last technological operations of manufacturing, the discharge lasts at least 3 and not more than 30, the value of I_nthe discharge current measured in amperes, support equal to (8÷12)·C₂₀during the whole process of discharge, where C₂₀numerically equal to the nominal capacity of the battery, And·h, measure the voltage drop U₀on the findings before n is commenced at the beginning of the discharge, measure the voltage drop U₁the conclusions at time t₁process discharge, measure the voltage drop U₂the conclusions at time t₂process discharge, measure the voltage drop U_tothe conclusions at time t_tothe end of discharge, calculate the value of ΔU, equal to the difference (U₁-U₂), compare the values U₀U_tothat ΔU with the control values U_0,counterU_{to the rear}that ΔU_counterfor each type of product and on the basis of such comparison, decide on product quality, thus consider quality products, for which U₀belongs to the interval U_0,counterU_togreater than or equal to U_{to the rear}that ΔU is less than or equal to ΔU_counter.