Testing Method and Device for Maximum Current of Battery

Abstract

An embodiment of the present invention discloses a method and device for testing the maximum current of a battery. The method for testing the maximum current of the battery includes: adjusting the state of charge of the battery to be tested to a preset state of charge threshold, and adjusting the temperature of the environment where the battery to be tested is located to a preset temperature; obtaining the charge and discharge cut-off voltages corresponding to different preset charge and discharge currents of the battery to be tested under a preset pulse time; and determining the maximum charge and discharge current of the battery to be tested under the preset pulse time according to the charge and discharge cut-off voltages. This solution can quickly and accurately determine the maximum charge and discharge current of the battery to be tested, so as to facilitate setting the battery management system to set safety limit conditions according to the maximum charge and discharge current of the battery to be tested, thereby ensuring that the battery can be charged and discharged efficiently and safely.

Description

Technical Field

[0001] The present invention relates to the technical field of battery detection, and in particular to a method and device for testing a maximum current of a battery. Background Art

[0002] In recent years, the production and sales of new energy vehicles have shown an explosive growth trend. Therefore, the development of new energy vehicles has become a consensus. Many countries have adjusted their development strategies and accelerated the layout of new energy industries, which has brought unprecedented opportunities for the vigorous development of new energy electric vehicles. Compared with traditional fuel vehicles, new energy vehicles do not emit any exhaust emissions and have a natural advantage in environmental protection. However, the convenience of new energy vehicles still needs to be improved. The more prominent problem is that it takes a long time to charge, which makes electric vehicles unsuitable for long-distance travel.

[0003] At present, the discharge capacity of lithium-ion batteries can basically meet the needs of people's daily life. During the driving of new energy vehicles, the greater the battery discharge current, the higher the engine power and the stronger the power. However, the discharge current of the battery is not the greater the better. Under high current discharge conditions, the saturation of the inorganic compound of nickel oxide, cobalt and manganese oxide formed at the solid-liquid junction of the positive electrode is too large, which will form more crystal precipitation and generate dendrites to damage the battery. At the same time, under high current discharge conditions, the battery temperature rise is higher, resulting in an increase in the internal side reactions of the battery cell, and the service life of the lithium-ion battery is accelerated. Therefore, it is necessary to know the maximum discharge current to better protect the lithium battery. In addition, the charging time of new energy vehicles is closely related to the charging current. The greater the charging current, the shorter the charging time. However, the consequence of rapid charging with excessive current is the precipitation of metallic lithium at the negative electrode. Especially at low temperatures, the kinetic conditions of the graphite negative electrode deteriorate, which makes it easier for metallic lithium to precipitate on the surface of the graphite negative electrode. In summary, in order to achieve rapid charging and discharging of electric vehicles without damaging the electrical properties of lithium-ion batteries, it is necessary to study the maximum acceptable charging current and maximum discharge current of power batteries. Summary of the invention

[0004] The embodiment of the present invention provides a method and device for testing the maximum current of a battery, so as to quickly and accurately determine the maximum charge and discharge current of a battery to be tested.

[0005] In a first aspect, an embodiment of the present invention provides a method for testing a maximum current of a battery, which includes:

[0006] Adjusting the state of charge of the battery to be tested to a preset state of charge threshold, and adjusting the temperature of the environment where the battery to be tested is located to a preset temperature;

[0007] Under the preset pulse time, obtaining the charge and discharge cut-off voltage corresponding to different preset charge and discharge currents of the battery to be tested;

[0008] Determine the maximum charge and discharge current of the battery under test at a preset pulse time according to the charge and discharge cut-off voltage.

[0009] Optionally, before adjusting the state of charge of the battery under test to a preset state of charge threshold, it further includes:

[0010] Discharge the fully charged battery under test at a first preset current at room temperature until the battery under test has zero power;

[0011] The battery under test after discharge is left to stand for a first preset time;

[0012] Repeat the steps of discharging the fully charged battery under test at the first preset current at room temperature to the step of leaving the battery under test after discharge to stand for the first preset time at least three times;

[0013] Obtain the total discharge capacity of the battery under test for the last time, and record the total discharge capacity as the capacitance calibration value of the battery under test.

[0014] Optionally, the method of adjusting the state of charge of the battery under test to a preset state of charge threshold includes:

[0015] Charge the battery under test after discharge at a second preset current until the state of charge of the battery under test is the preset state of charge threshold; the range of the second preset current is 0.2C to 1C;

[0016] After adjusting the temperature of the environment where the battery under test is located to a preset temperature, it further includes:

[0017] Leave the battery under test in the environment adjusted to the preset temperature for a second preset time; the range of the second preset time is 6h - 15h.

[0018] Optionally, the preset charge and discharge current includes a preset discharge current, and the charge and discharge cut-off voltage includes a discharge cut-off voltage;

[0019] The method for determining the discharge cut-off voltage includes:

[0020] At each preset pulse time, make the battery under test output different preset discharge currents, and detect the discharge cut-off voltage corresponding to each preset discharge current output by the battery under test.

[0021] Optionally, the preset charge and discharge current further includes a preset charge current, and the charge and discharge cut-off voltage further includes a charge cut-off voltage;

[0022] The method for determining the charge cut-off voltage includes:

[0023] At each preset pulse time, different preset charging currents are input to the battery to be tested, and the charging cut-off voltage corresponding to each preset charging current input to the battery to be tested is detected.

[0024] Optionally, the maximum charge and discharge current includes the maximum discharge current;

[0025] A method for determining the maximum discharge current of the battery to be tested at a preset pulse time includes:

[0026] Obtain the calibrated discharge cut-off voltage;

[0027] Screen out the discharge cut-off voltage with the smallest difference between the discharge cut-off voltage and the calibrated discharge cut-off voltage;

[0028] Determine the maximum discharge current of the battery to be tested according to the discharge cut-off voltage with the smallest difference between the discharge cut-off voltage and the calibrated discharge cut-off voltage.

[0029] Optionally, the maximum charge and discharge current further includes the maximum charging current;

[0030] A method for determining the maximum charging current of the battery to be tested at a preset pulse time includes:

[0031] Obtain the calibrated charging cut-off voltage;

[0032] Screen out the charging cut-off voltage with the smallest difference between the charging cut-off voltage and the calibrated charging cut-off voltage;

[0033] Determine the maximum charging current of the battery to be tested according to the charging cut-off voltage with the smallest difference between the charging cut-off voltage and the calibrated charging cut-off voltage.

[0034] Optionally, the range of the preset temperature is -30°C to 80°C.

[0035] Optionally, the range of the preset state of charge threshold is 0 to the capacitance calibration value;

[0036] The first preset current is 1C, and the range of the first preset time is 10 min to 30 min.

[0037] In a second aspect, an embodiment of the present invention further provides a test device for the maximum current of a battery, which includes:

[0038] An adjustment module for adjusting the state of charge of the battery to be tested to a preset state of charge threshold and adjusting the temperature of the environment where the battery to be tested is located to a preset temperature;

[0039] A charge and discharge cut-off voltage acquisition module, configured to acquire the charge and discharge cut-off voltages corresponding to different preset charge and discharge currents of the battery to be tested under a preset pulse time;

[0040] A maximum charge and discharge current determination module, configured to determine the maximum charge and discharge current of the battery to be tested under a preset pulse time according to the charge and discharge cut-off voltages.

[0041] In an embodiment of the present invention, by adjusting the state of charge of the battery to be tested to a preset state of charge threshold, and adjusting the temperature of the environment where the battery to be tested is located to a preset temperature, the state of charge of the battery to be tested is maintained at the preset state of charge threshold, and the temperature of the battery to be tested is maintained at the preset temperature, so as to subsequently detect the maximum charge and discharge current of the battery to be tested under the above conditions. At each preset pulse time, the battery to be tested outputs or inputs a preset charge and discharge current within the preset pulse time, so as to obtain the charge and discharge cut-off voltages corresponding to the battery to be tested when outputting or inputting different preset charge and discharge currents. Thus, the charge and discharge cut-off voltage corresponding to each preset charge and discharge current output by the battery to be tested can be compared with the calibrated cut-off voltage provided by the automobile manufacturer (customer), so as to determine that the preset charge and discharge current corresponding to the charge and discharge cut-off voltage closest to the calibrated cut-off voltage is the maximum charge and discharge current of the battery to be tested. In summary, the present solution can quickly and accurately determine the maximum charge and discharge current of the battery to be tested, so that the battery management system can set safety limit conditions according to the maximum charge and discharge current of the battery to be tested, thereby ensuring that the battery can be charged and discharged efficiently and safely. Description of the Drawings

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0043] Figure 1 It is a schematic flowchart of a method for testing the maximum current of a battery provided by an embodiment of the present invention;

[0044] Figure 2 It is a schematic flowchart of another method for testing the maximum current of a battery provided by an embodiment of the present invention;

[0045] Figure 3 It is a schematic flowchart of another method for testing the maximum current of a battery provided by an embodiment of the present invention;

[0046] Figure 4 It is a schematic flowchart of another method for testing the maximum current of a battery provided by an embodiment of the present invention;

[0047] Figure 5 Schematic flowchart of a method for determining the maximum discharge current of a battery under test at each preset pulse time provided by an embodiment of the present invention;

[0048] Figure 6 Schematic flowchart of a method for determining the maximum charge current of a battery under test at each preset pulse time provided by an embodiment of the present invention;

[0049] Figure 7 Schematic structural diagram of a test device for the maximum current of a battery provided by an embodiment of the present invention. Detailed implementation manners

[0050] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0051] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0052] Figure 1 Schematic flowchart of a test method for the maximum current of a battery provided by an embodiment of the present invention. This embodiment is applicable to the situation of batch determining the maximum charge and discharge currents of a battery under different test conditions. This method can be executed by a test device for the maximum current of a battery, and this device can be implemented in a hardware and / or software manner. The method specifically includes the following steps:

[0053] S110. Adjust the state of charge of the battery under test to a preset state of charge threshold, and adjust the temperature of the environment where the battery under test is located to a preset temperature.

[0054] Among them, the state of charge of the battery under test and the ambient temperature, etc. have a great influence on the maximum discharge current and maximum charge current of the battery under test. When the battery under test is in the charging condition, the higher the ambient temperature and the lower the state of charge of the battery under test, the larger the charging current that the battery under test can accept, and vice versa. When the battery under test is in the discharging condition, the higher the ambient temperature and the higher the state of charge of the battery under test, the larger the discharging current that the battery under test can accept, and vice versa. Therefore, it is necessary to determine the maximum charge current and maximum discharge current of the battery under test at different states of charge and different ambient temperatures.

[0055] Specifically, the preset state of charge threshold is the amount of electricity that the battery under test needs to maintain during the test. The preset temperature is the temperature that the environment where the battery under test is located needs to maintain during the test. The battery is placed in an environment with the preset temperature for a period of time so that the temperature of the battery is equal to the preset temperature to simulate the battery temperature in the working state of the battery under test, thereby facilitating the subsequent detection of the maximum charge and discharge currents when the battery temperature is the preset temperature. Among them, the automobile manufacturer will provide the temperature and state of charge when the battery is working according to the working requirements of the vehicle. That is, the preset state of charge threshold is the state of charge of the battery when the battery is working provided by the automobile manufacturer, and the preset temperature is the temperature when the battery is working provided by the automobile manufacturer.

[0056] Exemplarily, the range of the preset temperature is -30°C to 80°C. The range of the preset state of charge threshold is 0 to the total power of the battery under test.

[0057] Among them, the range of the preset temperature is determined according to the temperature range in which the battery under test can work safely, and the maximum value of the range of the preset state of charge threshold is determined according to the maximum amount of electricity that the battery under test can store.

[0058] S120. Obtain the charge and discharge cut-off voltages corresponding to different preset charge and discharge currents of the battery under test at the preset pulse time.

[0059] Among them, in the traditional battery maximum current test, a constant voltage charge and discharge maximum current test is adopted. The test result is the instantaneous maximum current that the battery can withstand, and the duration of this instantaneous maximum current is a few microseconds. In the actual working state, this instantaneous maximum current cannot work continuously and has no practical reference significance for the battery in the actual working state. In the actual working of the battery, the vehicle will require the battery to perform constant current charge and discharge under a fixed-time pulse. For example, when the vehicle starts, the battery needs a constant current discharge current pulse for 1 - 2 seconds, and when going uphill, the battery needs a constant current discharge current pulse for 30 - 60 seconds, etc. Therefore, the maximum charge and discharge currents of the battery at a given pulse time are required to facilitate the battery management system to limit the maximum charge and discharge currents of the battery while ensuring safe charge and discharge of the battery.

[0060] Specifically, the preset pulse time is the time for the battery under test to perform constant current discharge, and the automobile manufacturer will provide the preset pulse time according to the working requirements of the vehicle. Thus, through the current dotting test method, the battery under test can output or input a preset charge and discharge current within the preset pulse time, so as to obtain the charge and discharge cut-off voltages corresponding to different preset charge and discharge currents output or input by the battery under test.

[0061] S130. Determine the maximum charge and discharge current of the battery under test at the preset pulse time according to the charge and discharge cut-off voltage.

[0062] Among them, the charge and discharge cut-off voltage is the voltage of the battery under test when the test battery outputs or inputs different preset charge and discharge currents. The automobile manufacturer (customer) will provide the voltage of the battery under test when the battery under test outputs or inputs a current within the preset pulse time according to the working requirements of the vehicle. Thus, the charge and discharge cut-off voltage corresponding to each preset charge and discharge current output or input by the battery under test can be compared with the calibrated cut-off voltage provided by the automobile manufacturer (customer) to determine which preset charge and discharge current output or input by the battery under test has the charge and discharge cut-off voltage closest to the calibrated cut-off voltage. Among them, the preset charge and discharge current corresponding to the charge and discharge cut-off voltage closest to the calibrated cut-off voltage is the maximum charge and discharge current of the battery under test.

[0063] In the embodiment of the present invention, by adjusting the state of charge of the battery under test to the preset state of charge threshold and adjusting the temperature of the environment where the battery under test is located to the preset temperature, the state of charge of the battery under test is maintained at the preset state of charge threshold and the temperature of the battery under test is maintained at the preset temperature, so as to subsequently detect the maximum charge and discharge current of the battery under test under the above conditions. At each preset pulse time, the battery under test outputs or inputs a preset charge and discharge current within the preset pulse time, so as to obtain the charge and discharge cut-off voltages corresponding to different preset charge and discharge currents output or input by the battery under test. Thus, the charge and discharge cut-off voltage corresponding to each preset charge and discharge current output by the battery under test can be compared with the calibrated cut-off voltage provided by the automobile manufacturer (customer) to determine that the preset charge and discharge current corresponding to the charge and discharge cut-off voltage closest to the calibrated cut-off voltage is the maximum charge and discharge current of the battery under test. In summary, this solution can quickly and accurately determine the maximum charge and discharge current of the battery under test, so that the battery management system can set safety limit conditions according to the maximum charge and discharge current of the battery under test, thereby ensuring that the battery can be charged and discharged efficiently and safely.

[0064] Figure 2 FIG. is a schematic flow chart of another method for testing the maximum current of a battery provided by an embodiment of the present invention. The method specifically includes the following steps:

[0065] S210. Discharge the fully - charged battery to be tested at a first preset current at room temperature until the battery charge is zero.

[0066] Optionally, the first preset current is 1C.

[0067] Here, 1C means that the full capacity of the battery to be tested is discharged in 1 hour.

[0068] S220. Leave the discharged battery to be tested for a first preset time.

[0069] When there is current passing through the battery to be tested, due to the slowness of the electrochemical reaction, the charged state of the electrode is different from the reversible situation, which will lead to the deviation of the electrode potential. Exemplarily, excessive electrons accumulate on the electrode surface at the current outflow end of the battery to be tested, that is, the electrode potential tends to be negative, while the opposite is true at the current inflow end of the battery to be tested. Leaving the discharged battery to be tested for a first preset time can reduce the polarization voltage of the battery under test and balance the battery voltage to prevent battery damage.

[0070] Optionally, the range of the first preset time is 10 min - 30 min.

[0071] S230. Repeat at least three times the steps from discharging the fully - charged battery to be tested at a first preset current at room temperature to leaving the discharged battery to be tested for a first preset time.

[0072] S240. Obtain the total discharge capacity of the battery to be tested for the last time, and record the total discharge capacity as the capacitance calibration value of the battery to be tested.

[0073] When obtaining the total discharge capacity of the battery to be tested for the last time, the total discharge capacity of the battery under test has been stabilized, and the obtained total discharge capacity of the battery under test is representative.

[0074] S250. Adjust the state of charge of the battery to be tested to a preset state - of - charge threshold, and adjust the temperature of the environment where the battery to be tested is located to a preset temperature; where the range of the preset state - of - charge threshold is 0 - capacitance calibration value.

[0075] S260. At each preset pulse time, obtain the charge - discharge cut - off voltages corresponding to different preset charge - discharge currents of the battery to be tested.

[0076] S270. Determine the maximum charge - discharge current of the battery to be tested at each preset pulse time according to the charge - discharge cut - off voltages.

[0077] In summary, the purpose of the step of determining the capacitance calibration value of the battery under test before adjusting the state of charge of the battery under test to the preset state of charge threshold is: to prepare for adjusting the state of charge of the battery under test to the preset state of charge threshold. The preset state of charge threshold of the battery under test needs to be within the range of 0 to the capacitance calibration value. Otherwise, it is unreasonable and impossible to adjust the state of charge of the battery under test to the preset state of charge threshold.

[0078] Exemplarily, Figure 3 FIG. is a schematic flow chart of another method for testing the maximum current of a battery provided by an embodiment of the present invention. The method specifically includes the following steps:

[0079] S310. Charge the discharged battery under test with a second preset current until the state of charge of the battery under test reaches the preset state of charge threshold; the range of the second preset current is 0.2C to 1C.

[0080] Specifically, charging the discharged battery under test with a current of 0.2C to 1C means charging the battery under test at a rate that can fully charge the battery under test in half an hour to one hour. Charging the battery under test with a current of 0.2C to 1C will neither cause metallic lithium to precipitate at the negative electrode of the battery under test due to excessive current nor cause the charging time of the battery under test to be too long due to too small a current.

[0081] S320. Adjust the temperature of the environment where the battery under test is located to the preset temperature.

[0082] S330. Leave the battery under test in the environment adjusted to the preset temperature for a second preset time; the range of the second preset time is 6h - 15h.

[0083] Among them, leaving the battery under test in the environment adjusted to the preset temperature for the second preset time can make the temperature of the battery equal to the temperature of its environment, that is, the preset temperature, to simulate the battery temperature in the working state of the battery under test, so as to facilitate subsequent detection of the maximum charge and discharge current when the battery temperature is the preset temperature.

[0084] S340. At each preset pulse time, obtain the charge and discharge cut-off voltages corresponding to different preset charge and discharge currents of the battery under test.

[0085] S350. Determine the maximum charge and discharge current of the battery under test at each preset pulse time according to the charge and discharge cut-off voltages.

[0086] Optionally, the preset charge and discharge currents include a preset discharge current and a preset charge current, and the charge and discharge cut-off voltages include a discharge cut-off voltage and a charge cut-off voltage.

[0087] Specifically, the preset discharge current refers to the current output when the battery under test is discharging; the preset charge current refers to the current input when the battery under test is charging. The discharge cut-off voltage refers to the voltage of the battery under test when the battery under test outputs the preset discharge current; the charge cut-off voltage refers to the voltage of the battery under test when the battery under test inputs the preset charge current.

[0088] Optionally, the maximum charge and discharge current includes the maximum discharge current and the maximum charge current.

[0089] Among them, the maximum discharge current is determined according to the discharge cut-off voltage. Specifically, the preset discharge current corresponding to the discharge cut-off voltage closest to the calibrated cut-off voltage provided by the automobile manufacturer (customer) is the maximum discharge current of the battery under test. The maximum charge current is determined according to the charge cut-off voltage. Specifically, the preset charge current corresponding to the charge cut-off voltage closest to the calibrated cut-off voltage provided by the automobile manufacturer (customer) is the maximum charge current of the battery under test.

[0090] Exemplarily, Figure 4 is a schematic flowchart of another method for testing the maximum current of a battery provided by an embodiment of the present invention. The method specifically includes the following steps:

[0091] S410. Adjust the state of charge of the battery under test to a preset state of charge threshold, and adjust the temperature of the environment where the battery under test is located to a preset temperature.

[0092] S420. Make the battery under test output different preset discharge currents at each preset pulse time, and detect the discharge cut-off voltage corresponding to each preset discharge current output by the battery under test.

[0093] Exemplarily, at the preset pulse time t1, make the battery under test output the preset discharge current I 11 , and detect the discharge cut-off voltage V 11 corresponding to the output of the preset discharge current I 11 .

[0094] Adjust the state of charge of the battery under test to a preset state of charge threshold;

[0095] At the preset pulse time t1, make the battery under test output the preset discharge current I 12 , and detect the discharge cut-off voltage V 12 corresponding to the output of the preset discharge current I 12 .

[0096] Adjust the state of charge of the battery under test to a preset state of charge threshold;

[0097] And so on, until at the preset pulse time t1, make the battery under test output the preset discharge current I1n Detect the discharge cut-off voltage V corresponding to the output of the battery under test with a preset discharge current I 1n when discharging. 1n .

[0098] Under the preset pulse time t2, make the battery under test output a preset discharge current I 21 Detect the discharge cut-off voltage V corresponding to the output of the battery under test with a preset discharge current I 21 when discharging. 21 .

[0099] Adjust the state of charge of the battery under test to a preset state of charge threshold;

[0100] Under the preset pulse time t2, make the battery under test output a preset discharge current I 22 Detect the discharge cut-off voltage V corresponding to the output of the battery under test with a preset discharge current I 22 when discharging. 22 .

[0101] Adjust the state of charge of the battery under test to a preset state of charge threshold;

[0102] And so on, until under the preset pulse time t2, make the battery under test output a preset discharge current I 2n Detect the discharge cut-off voltage V corresponding to the output of the battery under test with a preset discharge current I 2n when discharging. 2n .

[0103] And so on, ……

[0104] Under the preset pulse time t m Make the battery under test output a preset discharge current I m1 Detect the discharge cut-off voltage V corresponding to the output of the battery under test with a preset discharge current I m1 when discharging. m1 .

[0105] Adjust the state of charge of the battery under test to a preset state of charge threshold;

[0106] Under the preset pulse time t m Make the battery under test output a preset discharge current I m2 Detect the discharge cut-off voltage V corresponding to the output of the battery under test with a preset discharge current I m2 when discharging. m2 .

[0107] Adjust the state of charge of the battery under test to a preset state of charge threshold;

[0108] And so on, until under the preset pulse time t m Make the battery under test output a preset discharge current Imn Detect the discharge cut-off voltage V corresponding to the output of the battery under test at the preset discharge current I mn when discharging. mn .

[0109] Among them, the number of preset pulse times is m, and the number of preset discharge currents is n.

[0110] S430. At each preset pulse time, make the battery under test input different preset charging currents, and detect the charging cut-off voltage corresponding to the battery under test when it inputs each preset charging current.

[0111] Exemplarily, at the preset pulse time t1', make the battery under test input the preset charging current I 11 ', and detect the charging cut-off voltage V 11 ' corresponding to the battery under test when it inputs the preset charging current I 11 '.

[0112] Adjust the state of charge of the battery under test to the preset state of charge threshold;

[0113] At the preset pulse time t1', make the battery under test input the preset charging current I 12 ', and detect the charging cut-off voltage V 12 ' corresponding to the battery under test when it inputs the preset charging current I 12 '.

[0114] Adjust the state of charge of the battery under test to the preset state of charge threshold;

[0115] And so on, until at the preset pulse time t1', make the battery under test input the preset charging current I 1W ', and detect the charging cut-off voltage V 1W ' corresponding to the battery under test when it inputs the preset charging current I 1W '.

[0116] At the preset pulse time t2', make the battery under test input the preset charging current I 21 ', and detect the charging cut-off voltage V 21 ' corresponding to the battery under test when it inputs the preset charging current I 21 '.

[0117] Adjust the state of charge of the battery under test to the preset state of charge threshold;

[0118] At the preset pulse time t2', make the battery under test input the preset charging current I 22 ', and detect the charging cut-off voltage V 22 ' corresponding to the battery under test when it inputs the preset charging current I 22 '.

[0119] Adjust the state of charge of the battery under test to a preset state of charge threshold;

[0120] And so on, until at a preset pulse time t2', the battery under test is input with a preset charging current I 2W ', and detect the charging cut-off voltage V 2W ' corresponding to when the battery under test is input with the preset charging current I 2W '.

[0121] And so on, ……

[0122] At a preset pulse time t Z ', the battery under test is input with a preset charging current I Z1 ', and detect the charging cut-off voltage V Z1 ' corresponding to when the battery under test is input with the preset charging current I Z1 '.

[0123] Adjust the state of charge of the battery under test to a preset state of charge threshold;

[0124] At a preset pulse time t Z ', the battery under test is input with a preset charging current I Z2 ', and detect the charging cut-off voltage V Z2 ' corresponding to when the battery under test is input with the preset charging current I Z2 '.

[0125] Adjust the state of charge of the battery under test to a preset state of charge threshold;

[0126] And so on, until at a preset pulse time t Z ', the battery under test is input with a preset charging current I ZW ', and detect the charging cut-off voltage V ZW ' corresponding to when the battery under test is input with the preset charging current I ZW '.

[0127] Wherein, the number of preset pulse times is Z, and the number of preset charging currents is w.

[0128] S440. Determine the maximum discharge current and the maximum charging current of the battery under test at each preset pulse time according to the charging cut-off voltage and the discharge cut-off voltage.

[0129] Exemplarily, according to the discharge cut-off voltage V 11 , the discharge cut-off voltage V 12 ... the discharge cut-off voltage V 1n , determine the maximum discharge current of the battery under test at the preset pulse time t1. According to the charging cut-off voltage V 11 ', the charging cut-off voltage V12 ’... charging cut-off voltage V 1W ’, and determine the maximum charging current of the battery under test at the preset pulse time t1’.

[0130] Exemplarily, Figure 5 FIG. is a schematic flow chart of a method for determining the maximum discharge current of a battery under test at each preset pulse time provided by an embodiment of the present invention. On the basis of the above embodiment, the method for determining the maximum discharge current of a battery under test at each preset pulse time is further described in detail:

[0131] S510. Obtain the calibrated discharge cut-off voltage.

[0132] The calibrated discharge cut-off voltage is the voltage of the battery under test when the battery under test outputs current at the preset pulse time provided by the automobile manufacturer (customer) according to the working requirements of the vehicle.

[0133] S520. Screen out the discharge cut-off voltage with the smallest difference from the calibrated discharge cut-off voltage.

[0134] Among them, the discharge cut-off voltage corresponding to each preset discharge current output by the battery under test is compared with the calibrated discharge cut-off voltage provided by the automobile manufacturer (customer), so as to determine which preset discharge current output by the battery under test has the discharge cut-off voltage closest to the calibrated discharge cut-off voltage, that is, screen out the discharge cut-off voltage with the smallest difference from the calibrated discharge cut-off voltage.

[0135] S530. Determine the maximum discharge current of the battery under test according to the discharge cut-off voltage with the smallest difference from the calibrated discharge cut-off voltage.

[0136] Among them, the preset discharge current output by the battery under test corresponding to the discharge cut-off voltage with the smallest difference from the calibrated discharge cut-off voltage is the maximum discharge current, that is, the preset discharge current corresponding to the discharge cut-off voltage closest to the calibrated discharge cut-off voltage is the maximum discharge current of the battery under test.

[0137] Exemplarily, Figure 6 FIG. is a schematic flow chart of a method for determining the maximum charging current of a battery under test at each preset pulse time provided by an embodiment of the present invention. On the basis of the above embodiment, the method for determining the maximum charging current of a battery under test at each preset pulse time is further described in detail:

[0138] S610. Obtain the calibrated charging cut-off voltage.

[0139] Among them, the calibrated charging cut-off voltage is the voltage of the battery under test provided by the automobile manufacturer (customer) according to the working requirements of the vehicle when a current is input during a preset pulse time.

[0140] S620. Screen out the charging cut-off voltage with the smallest difference from the calibrated charging cut-off voltage.

[0141] Among them, the charging cut-off voltage corresponding to each preset charging current output by the battery under test is compared with the calibrated charging cut-off voltage provided by the automobile manufacturer (customer), so as to determine which preset charging current input to the battery under test has the charging cut-off voltage closest to the calibrated charging cut-off voltage. That is, screen out the charging cut-off voltage with the smallest difference from the calibrated charging cut-off voltage.

[0142] S630. Determine the maximum charging current of the battery under test according to the charging cut-off voltage with the smallest difference from the calibrated charging cut-off voltage.

[0143] Among them, the preset charging current input to the battery under test corresponding to the charging cut-off voltage with the smallest difference from the calibrated charging cut-off voltage is the maximum charging current, that is, the preset charging current corresponding to the charging cut-off voltage closest to the calibrated charging cut-off voltage is the maximum charging current of the battery under test.

[0144] Figure 7 FIG. is a schematic structural diagram of a test device for the maximum current of a battery provided by an embodiment of the present invention. The test device for the maximum current of a battery includes:

[0145] An adjustment module 710, configured to adjust the state of charge of the battery under test to a preset state of charge threshold, and adjust the temperature of the environment where the battery under test is located to a preset temperature;

[0146] A charge and discharge cut-off voltage acquisition module 720, configured to acquire the charge and discharge cut-off voltages corresponding to different preset charge and discharge currents of the battery under test during a preset pulse time;

[0147] A maximum charge and discharge current determination module 730, configured to determine the maximum charge and discharge current of the battery under test during a preset pulse time according to the charge and discharge cut-off voltage.

[0148] In an embodiment of the present invention, an adjustment module 710 adjusts the state of charge of a battery under test to a preset state of charge threshold value, and adjusts the temperature of the environment where the battery under test is located to a preset temperature, so that the state of charge of the battery under test is maintained at the preset state of charge threshold value, and the temperature of the battery under test is maintained at the preset temperature, so as to subsequently detect the maximum charge and discharge current of the battery under test under the above conditions. A charge and discharge cut-off voltage acquisition module 720 causes the battery under test to output or input a preset charge and discharge current at each preset pulse time, so as to obtain the charge and discharge cut-off voltage corresponding to the battery under test when outputting or inputting different preset charge and discharge currents. Thus, a maximum charge and discharge current determination module 730 can compare the charge and discharge cut-off voltage corresponding to each preset charge and discharge current output by the battery under test with the calibrated cut-off voltage provided by an automobile manufacturer (customer), so as to determine that the preset charge and discharge current corresponding to the charge and discharge cut-off voltage closest to the calibrated cut-off voltage is the maximum charge and discharge current of the battery under test. In summary, the present solution can quickly and accurately determine the maximum charge and discharge current of the battery under test, so that a battery management system can set safety limit conditions according to the maximum charge and discharge current of the battery under test, thereby ensuring that the battery can be charged and discharged efficiently and safely.

[0149] The test device for the maximum current of the battery further includes: a capacitance calibration value acquisition module, specifically used for:

[0150] Discharge the fully charged battery under test at a first preset current at room temperature until the state of charge of the battery under test is zero;

[0151] Leave the discharged battery under test for a first preset time;

[0152] Repeat the steps of discharging the fully charged battery under test at a first preset current at room temperature to the step of leaving the discharged battery under test for a first preset time at least three times;

[0153] Obtain the total discharge capacity of the battery under test for the last time, and record the total discharge capacity as the capacitance calibration value of the battery under test.

[0154] The adjustment module includes:

[0155] A preset state of charge threshold value adjustment unit, configured to charge the discharged battery under test at a second preset current until the state of charge of the battery under test is the preset state of charge threshold value; the range of the second preset current is 0.2C to 1C;

[0156] The adjustment module further includes:

[0157] A DC blocking unit, configured to leave the battery under test in the environment adjusted to the preset temperature for a second preset time after adjusting the temperature of the environment where the battery under test is located to the preset temperature; the range of the second preset time is 6h - 15h.

[0158] Optionally, the preset charge and discharge current includes a preset discharge current, and the charge and discharge cut-off voltage includes a discharge cut-off voltage;

[0159] The charge and discharge cut-off voltage acquisition module includes:

[0160] A discharge cut-off voltage detection unit, configured to make the battery under test output different preset discharge currents at each preset pulse time, and detect the discharge cut-off voltage corresponding to each preset discharge current output by the battery under test.

[0161] Optionally, the preset charge and discharge current further includes a preset charge current, and the charge and discharge cut-off voltage further includes a charge cut-off voltage;

[0162] The charge and discharge cut-off voltage acquisition module further includes:

[0163] A charge cut-off voltage detection unit, configured to make the battery under test input different preset charge currents at each preset pulse time, and detect the charge cut-off voltage corresponding to each preset charge current input by the battery under test.

[0164] Optionally, the maximum charge and discharge current includes a maximum discharge current;

[0165] The maximum charge and discharge current determination module includes: a maximum discharge current unit, specifically configured to:

[0166] Obtain the maximum discharge cut-off voltage;

[0167] Screen out the discharge cut-off voltage with the smallest difference between the discharge cut-off voltage and the maximum discharge cut-off voltage;

[0168] The preset discharge current output by the battery under test corresponding to the discharge cut-off voltage with the smallest difference between the discharge cut-off voltage and the maximum discharge cut-off voltage is the maximum discharge current.

[0169] Optionally, the maximum charge and discharge current further includes a maximum charge current;

[0170] The maximum charge and discharge current determination module further includes: a maximum charge current unit, specifically configured to:

[0171] Obtain the maximum charge cut-off voltage;

[0172] Screen out the charge cut-off voltage with the smallest difference between the charge cut-off voltage and the maximum charge cut-off voltage;

[0173] The preset charge current input by the battery under test corresponding to the charge cut-off voltage with the smallest difference between the charge cut-off voltage and the maximum charge cut-off voltage is the maximum charge current.

[0174] The test device for the maximum current of the battery provided by the embodiment of the present invention can execute the test method for the maximum current of the battery provided by any embodiment of the present invention, and has corresponding functional modules and beneficial effects for executing this method.

[0175] It should be understood that various forms of the processes shown above can be used, and steps can be reordered, added or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is made herein.

[0176] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub - combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for testing the maximum current of a battery, characterized in that, Including: Adjust the state of charge of the battery under test to a preset state of charge threshold, and adjust the temperature of the environment where the battery under test is located to a preset temperature; At a preset pulse time, obtain the charge and discharge cut-off voltages corresponding to different preset charge and discharge currents of the battery under test; the charge and discharge cut-off voltages include the discharge cut-off voltage and the charge cut-off voltage; Determine the maximum charge and discharge current of the battery under test at the preset pulse time according to the charge and discharge cut-off voltages; The maximum charge and discharge current includes the maximum discharge current; The method for determining the maximum discharge current of the battery under test at the preset pulse time includes: Obtain the calibrated discharge cut-off voltage; Select the discharge cut-off voltage with the smallest difference between the discharge cut-off voltage and the calibrated discharge cut-off voltage; Determine the maximum discharge current of the battery under test according to the discharge cut-off voltage with the smallest difference between the discharge cut-off voltage and the calibrated discharge cut-off voltage; The maximum charge and discharge current also includes the maximum charge current; The method for determining the maximum charge current of the battery under test at the preset pulse time includes: Obtain the calibrated charge cut-off voltage; Select the charge cut-off voltage with the smallest difference between the charge cut-off voltage and the calibrated charge cut-off voltage; Determine the maximum charge current of the battery under test according to the charge cut-off voltage with the smallest difference between the charge cut-off voltage and the calibrated charge cut-off voltage.

2. The method for testing the maximum current of a battery according to claim 1, characterized in that, Before adjusting the state of charge of the battery under test to a preset state of charge threshold, it further includes: Discharge the fully charged battery under test at a first preset current at room temperature until the battery under test has zero charge; Let the battery under test after discharge stand for a first preset time; Repeat the steps of discharging the fully charged battery under test at the first preset current at room temperature to the step of letting the battery under test after discharge stand for the first preset time at least three times; Obtain the total discharge capacity of the battery under test for the last time, and record the total discharge capacity as the capacitance calibration value of the battery under test.

3. The method for testing the maximum current of a battery according to claim 1 or 2, characterized in that The method for adjusting the state of charge of the battery under test to a preset state of charge threshold includes: Charge the battery under test after discharge at a second preset current until the state of charge of the battery under test is the preset state of charge threshold; the range of the second preset current is 0.2C to 1C; After adjusting the temperature of the environment where the battery under test is located to a preset temperature, it further includes: Let the battery under test stand for a second preset time in the environment adjusted to the preset temperature; the range of the second preset time is 6h - 15h.

4. The method for testing the maximum current of a battery according to claim 1, wherein The preset charge and discharge current includes the preset discharge current; The method for determining the discharge cut-off voltage includes: At each preset pulse time, make the battery under test output different preset discharge currents, and detect the discharge cut-off voltage corresponding to each preset discharge current output by the battery under test.

5. The test method for the maximum current of the battery according to claim 1, wherein The preset charge and discharge current also includes the preset charge current; The method for determining the charge cut-off voltage includes: At each preset pulse time, input different preset charging currents to the battery under test, and detect the charging cut-off voltage corresponding to each preset charging current when the battery under test inputs the charging current.

6. The method for testing the maximum current of a battery according to claim 1, wherein The range of the preset temperature is -30°C to 80°C.

7. The method for testing the maximum current of a battery according to claim 2, wherein The range of the preset state of charge threshold is 0 to the capacitance calibration value; The first preset current is 1C, and the range of the first preset time is 10 min to 30 min.

8. A test device for the maximum current of a battery, characterized in that, Comprising: An adjustment module, configured to adjust the state of charge of the battery under test to a preset state of charge threshold, and adjust the temperature of the environment where the battery under test is located to a preset temperature; A charge and discharge cut-off voltage acquisition module, configured to obtain the charge and discharge cut-off voltages corresponding to different preset charge and discharge currents of the battery under test at a preset pulse time; the charge and discharge cut-off voltages include a discharge cut-off voltage and a charging cut-off voltage; A maximum charge and discharge current determination module, configured to determine the maximum charge and discharge current of the battery under test at a preset pulse time according to the charge and discharge cut-off voltage; The maximum charge and discharge current includes a maximum discharge current and a maximum charging current; The maximum charge and discharge current determination module includes a maximum discharge current unit and a maximum charging current unit; The maximum discharge current unit is configured to obtain a calibrated discharge cut-off voltage; screen out the discharge cut-off voltage with the smallest difference between the discharge cut-off voltage and the calibrated discharge cut-off voltage; determine the maximum discharge current of the battery under test according to the discharge cut-off voltage with the smallest difference between the discharge cut-off voltage and the calibrated discharge cut-off voltage; The maximum charging current unit is configured to obtain a calibrated charging cut-off voltage; screen out the charging cut-off voltage with the smallest difference between the charging cut-off voltage and the calibrated charging cut-off voltage; determine the maximum charging current of the battery under test according to the charging cut-off voltage with the smallest difference between the charging cut-off voltage and the calibrated charging cut-off voltage.

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