Method and apparatus for testing battery status

Abstract

The invention relates to a method and a device for checking a battery state in at least one battery, in particular for determining a battery failure, the method having at least the following steps: carrying out a first impedance test and determining the internal resistance of the battery, in which the battery is excited with a current profile having a defined frequency and the induced voltage response of the battery is measured, detecting and storing the measurement results of the first impedance test, in order to check a pulse- implemented load current test, i.e. a HRD test, of the battery, carrying out a second impedance test, detecting and storing the measurement results of the second impedance test, and evaluating the tests in such a way that the measurement results of the first impedance test and the measurement results of the second impedance test and / or the measurement results of the load current test are calculated in relation to one another, in particular correlated with one another, in such a way that therefrom a battery state, in particular whether there is a faulty battery, is derived.

Description

Technical Field

[0001] This invention relates to a method for inspecting the state of a battery in at least one battery. A second aspect of the invention relates to an apparatus for inspecting the state of a battery in at least one battery. Background Technology

[0002] For example, batteries used in motor vehicles may already have so-called battery faults during production. Therefore, the aim is to identify these battery faults as early as possible and to sort out the faulty batteries.

[0003] The most common battery failures can involve the battery's so-called separators.

[0004] The purpose of a battery separator is to spatially separate the cathode and anode, or the negative and positive electrodes, in a battery. The separator must be a barrier that electrically isolates the two electrodes from each other to prevent internal short circuits. However, the separator must also allow ions to pass through, thereby enabling electrochemical reactions within the battery cells.

[0005] The battery separator must be thin to minimize internal resistance and allow for high packing density, thereby achieving good power output and high capacity. Furthermore, the separator absorbs the electrolyte and ensures gas exchange within the closed battery cell.

[0006] A typical battery failure is a damaged separator.

[0007] In a battery failure known as a "short separator," the separator is shortened, thus failing to cover the geometrically complete contact surface between the separator and the electrode plates.

[0008] In addition, undesirable mass lump may occur, which accumulates as contaminants on the cathode or anode of the battery during manufacturing and thus significantly degrades the battery's performance.

[0009] There may also be bent electrode plates, also known as "bent plates" in English, which can cause a short circuit in the battery.

[0010] Another common battery failure is reverse polarity. This occurs when the electrodes are mistakenly used during battery manufacturing.

[0011] Battery failures can occur not only during battery manufacturing but also during operation or use. This is because batteries undergo multiple charge and discharge cycles throughout their lifespan. Furthermore, loads can arise due to temperature fluctuations. These factors contribute to different types of undesirable battery failures or defects.

[0012] A method for testing batteries in motor vehicles is disclosed in DE 10 2015 005 132 A1, wherein the cell voltage of the battery's individual cells is measured, and the measured cell voltage is automatically compared with test parameters. Thus, the reliability of batteries replaced at the vehicle factory can be assessed before their transport.

[0013] EP 1 037 063 A1 describes an identification device for fault identification in a battery pack, the device comprising a voltmeter and an ammeter. Fault identification is performed by determining the internal resistance of the battery pack.

[0014] A method for determining the lead impedance in a battery pack with multiple cells to identify line faults is disclosed in DE 10 2013 013 471 A1. Here, the presence of a line fault is inferred when the corresponding voltage differences across different cells within the battery pack have different signs.

[0015] The internal resistance or impedance of a battery is highly frequency-dependent. The internal resistance decreases with increasing frequency and may have a reactive component. Therefore, it is also called complex impedance, and the complex impedance is represented, for example, as a Bode plot based on its numerical value and phase, or as a trajectory plot based on its real and imaginary parts.

[0016] The most extensive observation of battery characteristics allows for so-called spectral impedance analysis, also known as electrical impedance spectroscopy, or EIS for short. Here, the (complex) internal resistance can be measured at multiple frequencies, for example, from 0.1 Hz to 1 kHz, which extends the measurement process by several minutes. Electrochemical characteristics can be read from the frequency response or trajectory. If this trajectory differs significantly from, for example, a typical curve, damage can be inferred.

[0017] For example, it is also known from DE 10 2004 063 431 A1 that the internal resistance of a battery can be determined by the current-time integral of the current curve and the voltage-time integral of the linearly decreasing voltage response.

[0018] As explained, impedance spectroscopy (EIS) is used in a known manner in electrochemical systems, i.e., batteries, such as lead-acid batteries, to analyze, characterize, and detect the electrochemical properties of the system. In this measurement technique, a sinusoidal signal with a frequency spectrum, for example, between μHz and MHz, is applied to the energy storage device, such as the battery, and the frequency response is analyzed.

[0019] Impedance reflects the increase in amplitude and phase shift. The impedance is measured at different frequencies, ranging from multiple kilohertz to millihertz, to detect the battery's impedance spectrum. Changes in battery characteristics due to temperature, state of charge (SOC), or current load are reflected in correspondingly altered impedance curves.

[0020] As is also known from EP 1 892 536 A1, impedance spectroscopy measurements are performed by monitoring the state of aging (SoH), state of charge (SoC), and state of functional fulfillment (SoF). In impedance spectroscopy measurements, the battery is unloaded, thus the method is only applicable to determining the operating state, i.e., the state of charge and the aging state. These two parameters are calculated by the capacity currently achievable under a small load current and at a defined temperature, or the maximum capacity achievable in a fully charged state.

[0021] Based on this, DE 10 2016 216 664 A1 proposes a method for determining the functional reliability of a low-voltage battery in a vehicle that is at least partially electrically driven, wherein the low-voltage battery is subjected to a test pulse, and the functional reliability of the battery is derived from the correlation between the battery voltage curve obtained during the test pulse and a predetermined functional requirement, wherein functional reliability is given when the battery voltage curve during the test pulse meets multiple independent test criteria.

[0022] Therefore, in known methods, a single test is first performed to determine the battery's fault in order to accurately identify multiple faults.

[0023] In known methods, a single measurement of the battery is first performed to accurately identify battery faults. The battery is then placed in an isolation facility for several weeks, that is, stored in a warehouse, for example. The battery is then tested again to identify any other faults that may be present.

[0024] This is disadvantageous because large quantities of batteries need to be stored for weeks, resulting in huge storage costs.

[0025] The known testing methods can only identify a maximum of three of the five most common faults. Two of these most common faults can only be identified after battery delivery and after one to two years of operation.

[0026] The fault identification is related to the degree of fault impact within a predetermined test time. A common test in battery manufacturing is the high-current test (HRD). However, this test can only identify faults with directly different electrical measurements, such as obviously defective battery cells or interrupted battery cell layers.

[0027] However, in order to determine in quality control whether a newly manufactured battery has a fault that leads to high voltage or capacity loss, the battery is stored in an "isolation station" so that the voltage or capacity loss can be tested several weeks later.

[0028] Using known testing methods, some battery failures only take effect after the battery has been subjected to long-term mechanical or thermal loads or after aging. For example, a bent plate may cause a short circuit after a certain amount of vibration or aging (sulfation).

[0029] Furthermore, a drawback of the known prior art is that it can only insufficiently determine the functional implementation of the battery. Summary of the Invention

[0030] Based on the aforementioned drawbacks, the objective of this invention is to provide a method and apparatus of the type described at the beginning, which enables particularly early and accurate identification of battery faults in a simple manner.

[0031] This task is solved by a method for inspecting the state of at least one battery according to the present invention. This task is also solved by a device for inspecting the state of at least one battery according to the present invention.

[0032] This invention relates to a method for inspecting the state of a battery in at least one battery, particularly for determining battery faults, the method comprising at least the following steps:

[0033] A first impedance test is performed to determine the battery's internal resistance, wherein the battery is loaded with a current profile and the resulting voltage response is measured.

[0034] Detect and store the measurement results of the first impedance test.

[0035] To test the pulse or discharge pulse, preferably a high-current load test of the battery is performed within a few seconds.

[0036] Preferably, the second impedance test is performed after an interval of 1 to 10 seconds, particularly 2 seconds.

[0037] Detect and store the measurement results of the second impedance test.

[0038] The test is evaluated by correlating and calculating the results of the first impedance test, the second impedance test, and / or the load current test in such a way that the battery condition, and in particular whether there is a faulty battery, can be deduced.

[0039] In other words, an impedance test of the battery is performed first. This battery test can last for several seconds. Then a high-current load test is performed, followed by another impedance test as a comparison with the first impedance test.

[0040] The measurement results of the first impedance test are correlated with those of the second impedance test, for example, by calculating their correlation. Based on these results and through a high-current test, defective batteries can then be filtered out and sorted out in a simple manner.

[0041] As explained, internal resistance characterizes a battery’s ability to handle a given amount of energy before the voltage drops to a predetermined boundary value, such as below the open circuit voltage.

[0042] The total internal resistance of a battery consists of ohmic resistance and charge transfer resistance (also known as polarization resistance). Ohmic resistance includes electrode resistance, electrolyte resistance, separator resistance, and contact resistance of each component, and can be evaluated at a single frequency using electrochemical impedance spectroscopy, also known as ACR.

[0043] To determine the charge transfer resistance (CCR) of a battery, the battery can be discharged with two rapid pulses, and the voltage drop can be evaluated corresponding to the discharge current. This process uses only the battery's direct current and is also known as a DCR test. In this manner, the battery's total internal resistance can be obtained, and the CCR can be determined accordingly. These two test methods, ACR and DCR, offer the maximum possibility of detecting battery power during a very limited test time, which is particularly advantageous on production lines because it does not extend cycle time.

[0044] In high-current load testing, the battery is discharged at a relatively high current using a test pulse or discharge pulse, and the voltage is observed during and after the test. This load alters the battery's electrochemical characteristics. These alterations can be reflected by impedance analysis to show the ratio of faulty to fault-free batteries.

[0045] Also known as High Rate Discharge (HRD) in English, this high-current load test utilizes the battery to discharge at a high current. The battery can discharge at, for example, more than 10 times its rated charge rate (C-Rate).

[0046] The charge rate describes the charging or discharging current of a battery, particularly a refrigerated battery, relative to its capacity. The charge rate allows us to determine, for example, the maximum permissible charging and discharging current based on the rated capacity. The coefficient is also used, conversely, to determine the battery capacity based on the discharge current intensity. The C-coefficient is defined as the quotient of the current and the capacity. For example, at a capacity of 70 Ah, 10 times the discharge current corresponds to a current intensity of 700 A. Batteries can discharge at a constant current, constant voltage, or constant power.

[0047] In high-current load tests, the open circuit voltage (OCV) and the constant current voltage (CCV) at the end of the discharge pulse can be used to determine the battery state.

[0048] The batteries being tested can be, for example, so-called flooded lead-acid batteries, sealed batteries, or lithium-ion batteries.

[0049] According to an advantageous first design of the invention, a difference is formed between the measurement results of the first impedance test and the measurement results of the second impedance test, so as to deduce whether the difference is outside a predetermined range. Based on the difference, it can be determined whether an unacceptable deterioration in the battery state has occurred or is about to occur. For example, a faulty battery may have a deviation of 10% to 30%, particularly 20%, relative to a fault-free battery.

[0050] According to an advantageous further aspect of the invention, the high-current load test is performed for a duration of approximately 1 to 10 seconds, particularly 3 seconds. This time period helps ensure battery quality and can filter out multiple faulty batteries. As is known in the prior art, significantly longer test times lead to production delays and substantial energy losses in the manufacturing process.

[0051] In another advantageous variant of the invention, the measured values ​​of the various measurements can be freely configured to be correlated with each other. Because the measured values ​​of each method step are stored, these values ​​can be compared against different test curves and considered for further evaluation and statistical calculations. The user can set specific test parameters, such as current, voltage, test duration, interval time, and evaluation boundaries, based on the battery type and capacity. The current measured values ​​can then be statistically compared with previous measurement data. The average and standard deviation of the results can be derived from this and used, for example, to define the evaluation boundaries.

[0052] In an advantageous embodiment of the invention, multiple, particularly three to five, individual test methods are performed on a single battery, and the results of each measurement are correlated with each other to identify faulty batteries. For example, test methods such as constant current discharge, constant voltage discharge, constant power discharge, DC internal resistance measurement, and AC impedance measurement can be performed sequentially in a test sequence, and the corresponding measurement results are combined with each other.

[0053] According to a further aspect of the invention, the first impedance test and / or the second impedance test of the battery are performed at a fixed frequency, particularly at a frequency of approximately 1 kHz. This measurement is also known as a single-frequency measurement. The selected frequency is related to the battery type and the test time. For example, in the case of lead-acid batteries, the impedance value has a stable real part and a small imaginary part from approximately 100 Hz to approximately 1 kHz. Single-frequency measurement is advantageous compared to measurements at a frequency spectrum, as it shortens the test time and also provides an effective indication of the battery. The single-frequency method is also known as the ACR test, which displays the battery's internal resistance in ohms, also known as the electrolyte resistance. Here, the method can be performed in milliseconds. This allows for seamless application in so-called end-of-line testing machines on the production line during battery manufacturing.

[0054] In a further embodiment of the invention, the first impedance test and / or the second impedance test of the battery are performed at multiple frequencies, particularly at approximately 0.5 Hz, 50 Hz, and 500 Hz. This provides the possibility of obtaining an optimal frequency range, at which the measurement results are as efficient as possible.

[0055] Another advantageous design of the invention involves performing the first impedance test and / or the second impedance test of the battery in a certain frequency spectrum, particularly in the frequency spectrum between 0.1 Hz and 1 MHz.

[0056] Fourier series can be used when calculating impedance. This allows the parameters of the battery's equivalent circuit to be identified by using a defined frequency range of the spectrum, for example, 0.1 Hz to 7.5 kHz for lead-acid batteries. The impedance measurements can be expressed as real and imaginary numbers, for example, by using a so-called Nyquist plot, which can be transformed into complex numbers via Fourier transform. For this purpose, the battery must be excited with a spectrum of approximately 0.1 Hz to 7.5 kHz and the signal response measured. The parameters of the equivalent circuit diagram can be determined or read from the plot. This parameterization helps to better examine the battery's electrochemical characteristics. Faults in the battery can also be reflected through impedance analysis in this manner.

[0057] According to another variation of the invention, the discharge pulse for high-current load testing is maintained for a pulse duration of 1 to 10 seconds, preferably 2 to 4 seconds, and particularly 3 seconds. This increases production cycle time and reduces energy loss.

[0058] Within the range of lead-acid batteries, the test pulse or discharge pulse for high-current load testing can be set to have a current intensity of approximately 500 to 3000 amperes. The selected current intensity is related to the battery capacity and can be determined based on the battery manufacturer and the duration of the load. In principle, the battery's charge rate applies here; the battery can be loaded with a value between, for example, 1 to 20 times its rated capacity. As explained, the charge rate describes the charging or discharging current of a battery, particularly a refrigerated battery, relative to its capacity. The maximum permissible charging and discharging current can be given, for example, based on the rated capacity, using the charge rate. For example, a charge rate of 15 times for a 100 AH battery corresponds to a current intensity of 1500 A.

[0059] In an advantageous manner, the current intensity of the test pulse or discharge pulse in the high-current load test can be gradually increased. This allows for the determination of the optimal load factor for the corresponding battery structure, under which faults can be identified as effectively as possible. Furthermore, unnecessary loads on the battery are avoided.

[0060] It can also be configured to generate a discharge curve, i.e., voltage and current, during battery discharge during testing, in order to accurately check the battery's characteristics under load. The battery can be measured and the results stored under constant current, constant voltage, or constant power.

[0061] According to an independent concept of the present invention, an apparatus is provided for inspecting the state of a battery in at least one battery, particularly for implementing the aforementioned method. The apparatus has an impedance measuring device for performing at least one first impedance test and a second impedance test by determining the internal resistance of the battery, wherein a high current device is provided for performing a high current load test of the battery with a test pulse or a discharge pulse, and wherein the apparatus has an evaluation unit for evaluating the test.

[0062] According to an advantageous design of the invention, the evaluation unit is designed to detect and store the measurement results of the first impedance test and the second impedance test, and in particular, by means of the evaluation unit, to calculate the measurement results of the first impedance test and the second impedance test and / or the measurement results of the load current test in such a way that the battery status, in particular whether there is a faulty battery, can be deduced. Attached Figure Description

[0063] Further objects, advantages, features, and applications of the invention will become apparent from the following description of embodiments based on the accompanying drawings. Here, all features described and / or illustrated also constitute the subject matter of the invention individually or in any meaningful combination, regardless of their combination in the claims or in the backreferences of the claims.

[0064] This is shown schematically in part:

[0065] Figure 1 The flowchart of the method for determining battery state.

[0066] Figure 2 Devices used to determine battery status, and

[0067] Figure 3 An exemplary graph showing the measurement results.

[0068] Components that are identical or have the same function are given the same reference numerals in the views shown below in the accompanying drawings according to the embodiments, in order to improve readability. Detailed Implementation

[0069] For example, a battery 10 used in a motor vehicle may already have a so-called battery fault during production. Therefore, the aim is to identify the battery fault as early as possible and sort out the faulty battery 17.

[0070] As previously described, one of the typical battery failures is a damaged separator, also known as a "damaged separator" in English. In the case of a battery failure called a "short separator," there is a shortened separator, which fails to cover the contact surface, resulting in a complete contact surface in the geometry between the separator and the electrode plates.

[0071] In addition, undesirable mass lumps or material accumulations may occur. During manufacturing, these mass lumps or material accumulations accumulate as contaminants on the cathode or anode of the battery, thereby significantly degrading the battery's performance.

[0072] There may also be bent electrode plates, also known as "bent plates" in English, which can cause a short circuit in the battery.

[0073] Another common battery malfunction is reverse polarity. This occurs when the electrodes are mistakenly used during the manufacture of battery 10.

[0074] In order to determine the fault now during the manufacturing of battery 10, so that faulty batteries 17 can be directly sorted out, the present invention proposes a method and apparatus 11 for determining battery status.

[0075] exist Figure 1 The flowchart shown below illustrates a method for inspecting the state of at least one battery 10, the method being particularly for determining battery faults, the method comprising at least the following steps:

[0076] A first impedance test 1 is performed to determine the internal resistance of battery 10, wherein battery 10 is loaded with a current curve having a defined frequency, and the resulting voltage response of battery 10 is measured. The battery test may last for several seconds.

[0077] Here, the measurement result of the first impedance test 1 is detected and stored. This measurement value is used as a reference value for subsequent, additional impedance tests.

[0078] Then, a high-current load test 3 is performed on battery 10 using a test pulse or a discharge pulse. In the high-current load test 3, battery 10 is discharged at a relatively high current using a test pulse or discharge pulse, and the voltage is observed during and after the test. The electrochemical characteristics of battery 10 are altered by subjecting it to a load. These alterations can be fully utilized through impedance analysis, as they reflect the ratio of faulty to fault-free batteries 10.

[0079] Battery 10, for example, can discharge at a so-called charge rate greater than 10 times, where the charge rate describes the charging or discharging current of the battery, particularly a accumulator, relative to its capacity. For example, in the case of a 70 Ah capacity, a 10-fold increase in discharge current corresponds to a current intensity of 700 A. The battery can discharge at a constant current, constant voltage, or constant power.

[0080] In the high-current load test 3, the open-circuit voltage and the load voltage at the end of the discharge pulse can be used to determine the battery status.

[0081] The battery 10 being tested can be, for example, a so-called flooded lead-acid battery, or a sealed battery, or a lithium-ion battery.

[0082] Next, after loading the battery 10, a second impedance test 2 is performed, and the measurement result of the second impedance test 6 is also detected and stored. The second impedance test 2 is used as a comparison measurement with the first impedance test 1.

[0083] The first impedance test 1 and / or the second impedance test 2 of battery 10 can be performed at a fixed frequency, particularly at a frequency of approximately 1 kHz. This measurement is also known as a single-frequency measurement. The selected frequency is related to the battery type and the allowed test time. For example, in the case of lead-acid batteries, the impedance value has a stable real part and a small imaginary part from approximately 100 Hz to approximately 1 kHz. However, it is also possible to perform the first impedance test 1 and / or the second impedance test 2 of battery 10 at multiple frequencies, particularly at approximately 0.5 Hz, 50 Hz, and 500 Hz, or within a certain spectrum, particularly between 0.1 Hz and 1 MHz.

[0084] In this invention, it is important to evaluate the tests described in 7, namely impedance tests 1 and 2, and the high-current load test 3 performed between said tests. In the evaluation unit 16, the measurement results of the first impedance test 1 and the second impedance test 2 and / or the measurement results of the high-current load test 3 are calculated in such a way that the battery condition, in particular the presence or absence of a faulty battery 17, can be deduced.

[0085] In this example, a difference 8 is generated between the measurement results of the first impedance test 1 and the second impedance test 2, so as to deduce whether the difference 8 is outside a predetermined range 9. Based on the difference 8, it is determined whether an unacceptable deterioration in the battery state has occurred or is about to occur. A faulty battery 10 may, for example, have a deviation of 10% to 30%, particularly 20%, relative to a fault-free battery 10.

[0086] exist Figure 3 The results of the test are shown in the figure. The number 4 of the batteries 10 tested is marked on the x-axis, meaning each battery 10 tested is assigned a single number with a corresponding measurement point. Therefore, 26 batteries 10 were tested.

[0087] The difference 8 between the measured value of the first impedance measurement 1 and the measured value of the second impedance measurement 2 is shown on the y-axis. In this embodiment, the difference is in the range of 0.09 and 0.17.

[0088] as Figure 3 As can be further understood, for the purpose of evaluation, the boundary 9, namely 0.13, of the difference 8 between impedance measurements 1 and 2 is predetermined. A predetermined interval 9 can also be considered.

[0089] Batteries 10 with configured numbers 1 to 21 all have a difference of 8, which is below boundary 9. However, the difference of 8 in batteries 10 with numbers 22 to 26 is clearly above boundary 9. This battery 10 is a faulty battery 17, i.e., a battery with a battery malfunction.

[0090] Figure 2 An apparatus 11 is shown for inspecting the state 10 of at least one battery, particularly for implementing the aforementioned method, the apparatus having an impedance measuring device 12 for performing at least one first impedance test 1 and a second impedance test 2 by determining the internal resistance 10 of the battery.

[0091] Of course, in the context of this invention, it is also possible to implement more than two impedance tests 1, 2 and multiple high-current load tests 3 and combine the results of each measurement accordingly.

[0092] In addition, a high-current device 13 is provided for performing and measuring the load current test 3 of the battery 10 with a test pulse or discharge pulse.

[0093] The measuring contacts used for impedance measurement are indicated by reference numeral 15, particularly four-pole measuring contacts. Current terminals 14 are connected to the measuring contacts, and these current terminals can be designed as clamp-on current terminals, i.e., current clamps.

[0094] In addition, the device 11 has an evaluation unit 16 for evaluating the test described in 7. The evaluation unit 16 is designed to detect and store the measurement results 5 of the first impedance test 1, the measurement results of the second impedance test 2, and / or the measurement results of the high current test 3.

[0095] Evaluation unit 16 may be a programmable logic controller (SPS) for controlling or regulating device 11 and is digitally programmed. In its simplest form, the SPS has inputs, outputs, a running system (firmware), and an interface through which an application program can be loaded. The application program determines how the outputs should be switched based on the inputs. Furthermore, in this embodiment, evaluation unit 16 is designed to analyze impedance test measurements and output the measurement results.

[0096] In the context of this invention, it is also possible to implement multiple, particularly three to five, individual test methods on a single battery 10, and correlate the results of each measurement with each other in order to then identify faulty batteries 17. For example, test methods such as constant current discharge, constant voltage discharge, constant power discharge, DC internal resistance measurement, and AC impedance measurement of battery 10 can be performed sequentially in a test sequence, and the corresponding measurement results can be combined with each other.

[0097] List of reference numerals

[0098] 1. First Impedance Test

[0099] 2. Second Impedance Test

[0100] 3. High Current Load Test

[0101] 4. Number of batteries tested

[0102] 5. Detect and store measurement results

[0103] 6. Detect and store measurement results

[0104] 7. Evaluation Test

[0105] 8. Poor

[0106] 9. Pre-defined interval or predetermined boundary

[0107] 10 batteries

[0108] 11 devices

[0109] 12 Impedance measuring device

[0110] 13 High Current Devices

[0111] 14 Current terminals

[0112] 15 Measuring contacts for impedance measurement

[0113] 16 Evaluation Units

[0114] 17. Faulty battery.

Claims

1. A method for inspecting the state of a battery in at least one battery (10), the method comprising at least the following steps: First, a first impedance test (1) is performed to determine the internal resistance of the battery (10), wherein the battery (10) is excited with a current curve having a defined frequency, and the induced voltage response of the battery (10) is measured. The measurement results (5) of the first impedance test (1) are detected and stored. Next, a high-current load test (3) of the battery (10) is performed using a test pulse or a discharge pulse. Then the second impedance test (2) is performed. The measurement results (6) of the second impedance test (2) are detected and stored. The evaluation (7) of the first impedance test, the second impedance test, and the high-current load test is carried out by correlating the measurement results of the first impedance test (1) and the second impedance test (2) with each other so as to deduce the battery state. in, The difference (8) between the measurement result of the first impedance test (1) and the measurement result of the second impedance test (2) is formed so as to deduce whether the value of the difference (8) is outside a predetermined boundary (9) or a predetermined range.

2. The method according to claim 1, characterized in that, The high current load test (3) is performed for a duration of 1 to 10 seconds.

3. The method according to claim 1 or 2, characterized in that, The measured values ​​of each measurement can be freely configured and correlated with each other.

4. The method according to claim 1 or 2, characterized in that, Multiple individual test methods are performed on a battery (10), and the results of the individual measurements are correlated with each other in order to identify the faulty battery (10).

5. The method according to claim 4, characterized in that, The testing methods for the battery (10) are to discharge the battery (10) under constant current, discharge under constant voltage, discharge under constant power, measure the DC voltage internal resistance, or measure the AC resistance.

6. The method according to claim 1 or 2, characterized in that, The first impedance test (1) and / or the second impedance test (2) of the battery (10) are performed at a fixed frequency.

7. The method according to claim 1 or 2, characterized in that, The first impedance test (1) and / or the second impedance test (2) of the battery (10) are performed at multiple frequencies.

8. The method according to claim 1 or 2, characterized in that, The first impedance test (1) and / or the second impedance test (2) of the battery (10) are performed under a certain frequency spectrum.

9. The method according to claim 1 or 2, characterized in that, The test pulse of the load high current test (3) is maintained for a pulse duration of 1 to 10 seconds.

10. The method according to claim 1 or 2, characterized in that, The test pulse of the load current test (3) has a current intensity of 500 to 3000 amperes, or the test pulse of the load current test (3) has a current intensity corresponding to a value between 1 and 20 times the charging rate of the battery (10).

11. The method according to claim 1 or 2, characterized in that, The current intensity of the test pulse in the load high current test (3) is gradually increased.

12. The method according to claim 1 or 2, characterized in that, The battery (10) is measured to discharge under constant current, constant voltage, or constant power, and the measurement results are stored.

13. The method according to claim 1, characterized in that, The method is used to determine battery faults.

14. The method according to claim 2, characterized in that, The load high current test (3) is performed for a duration of 3 seconds.

15. The method according to claim 3, characterized in that, The measured values ​​of each measurement include the measured values ​​of the first impedance test (1) and the second impedance test (2) and / or the measured values ​​of the load current test (3).

16. The method according to claim 4, characterized in that, A single test method is implemented on a battery (10) with between 3 and 5 individual test samples.

17. The method according to claim 5, characterized in that, Some or all of the test methods described herein are performed sequentially in the test sequence, and the corresponding measurement results are combined with each other.

18. The method according to claim 6, characterized in that, The first impedance test (1) and / or the second impedance test (2) of the battery (10) are performed at a frequency of about 1 kHz.

19. The method according to claim 7, characterized in that, The first impedance test (1) and / or the second impedance test (2) of the battery (10) are performed at 0.5 Hz, 50 Hz and 500 Hz.

20. The method according to claim 8, characterized in that, The first impedance test (1) and / or the second impedance test (2) of the battery (10) are performed in the spectrum between 0.1 Hz and 1 MHz.

21. The method according to claim 9, characterized in that, The test pulse of the load high current test (3) is held for a pulse duration of 2 to 4 seconds.

22. The method according to claim 9, characterized in that, The test pulse of the load high current test (3) is held for a pulse duration of 3 seconds.

23. An apparatus (11) for inspecting the state of a battery in at least one battery (10), for implementing the method according to any one of the preceding claims, said apparatus having an impedance measuring device (12) for implementing at least one first impedance test (1) and a second impedance test (2) by determining the internal resistance of the battery (10), wherein, A high-current device (13) is provided for performing a load high-current test (3) on the battery (10) with a test pulse or discharge pulse, wherein the device (11) has an evaluation unit (16) for evaluating (7) the first impedance test, the second impedance test and the load high-current test, wherein the evaluation unit (16) is designed to detect and store the measurement results (5) of the first impedance test (1) and the measurement results of the second impedance test (2), wherein the measurement results of the first impedance test (1) and the measurement results of the second impedance test (2) are correlated with each other by means of the evaluation unit (16) so that the battery state is derived therefrom.

Images