Method, device and equipment for testing SOC-OCV curve of battery and medium

Abstract

The invention discloses a battery SOC-OCV curve test method, which comprises the following steps: carrying out charging and discharging operation on a to-be-tested battery at room temperature until the to-be-tested battery reaches a current target battery SOC, obtaining a voltage value of the to-be-tested battery at a target temperature, continuously carrying out charging and discharging operation on the to-be-tested battery at room temperature until the to-be-tested battery reaches the current target battery SOC, and obtaining a voltage value of the to-be-tested battery at the target temperature. Enabling the to-be-tested battery to reach a target battery charge state different from the current target battery charge state until a plurality of voltage values corresponding to a plurality of different target battery charge states at the target temperature are obtained; the capacity required for charging and discharging the to-be-tested battery to reach the charge state of the target battery is determined according to the charge state of the target battery and the calibrated capacity of the to-be-tested battery at the room temperature; and determining a battery SOC-OCV curve at the target temperature according to the plurality of target battery states of charge and the plurality of voltage values corresponding to the target battery states of charge. The curve obtained by the method is more accurate. The invention further discloses a testing device, electronic equipment and a readable storage medium.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a method for testing a battery SOC-OCV curve, a device for testing a battery SOC-OCV curve, an electronic device, and a computer-readable storage medium. Background Art

[0002] As a core component of an automotive powertrain, the power battery is not only the source of power for new energy vehicles but also a key factor in determining vehicle range. In the field of battery management technology, accurately estimating a battery's state of charge (SOC) using scientific and rational methods is crucial. The open-circuit voltage method (OCV) is one of the current mainstream techniques for estimating battery SOC. This method constructs an SOC-OCV characteristic curve through multiple measurement tests, allowing the battery's SOC at that moment to be directly determined based on the measured open-circuit voltage value.

[0003] In the prior art, the SOC-OCV curve testing method typically determines the battery capacity at room temperature, and then determines the current rate available for charge and discharge. The battery is then charged and discharged at a specific target temperature at a specific rate and sampling interval to achieve a fixed SOC value. The battery is then allowed to rest at the target temperature for a period of time, and finally the corresponding OCV value is obtained, thereby obtaining a complete SOC-OCV curve. However, during the process of adjusting the battery SOC using this method, the chemical reaction rate within the battery is affected by temperature, and the heat generated by charge and discharge can cause the actual battery temperature to deviate from the target temperature. The actual capacity of the battery at the target temperature may be inconsistent with the capacity measured at room temperature, resulting in a distortion of the SOC calculation benchmark and an inaccurate SOC-OCV curve. Summary of the Invention

[0004] The present invention proposes a method for testing a battery SOC-OCV curve to solve the above problems.

[0005] In a first aspect, an embodiment of the present invention discloses a method for testing a battery SOC-OCV curve, comprising:

[0006] performing charge and discharge operations on the battery under test at room temperature until the battery under test reaches a current target battery state of charge, placing the battery under test at a target temperature, obtaining a voltage value corresponding to the current target battery state of charge of the battery under test at the target temperature, and continuing to perform charge and discharge operations on the battery under test at the current target battery state of charge at room temperature so that the battery under test reaches a target battery state of charge different from the current target battery state of charge, until a plurality of voltage values ​​corresponding to a plurality of different target battery states of charge at the target temperature are obtained;

[0007] The charge and discharge operation includes charging or discharging. The capacity required for the battery to be tested to achieve a target battery state of charge by performing the charge and discharge operation is determined based on the target battery state of charge and the calibrated capacity of the battery to be tested at room temperature. The calibrated capacity is the capacity of the battery to be tested when it reaches a stable state.

[0008] A battery SOC-OCV curve of the battery to be tested at a target temperature is determined according to a plurality of target battery states of charge and a plurality of corresponding voltage values.

[0009] By adopting the above technical solution, in the battery SOC-OCV curve testing method of the present invention, the calibrated capacity of the battery to be tested is determined at room temperature, and charging and discharging are performed at room temperature, which can ensure the accuracy of capacity calibration and the stability of the charging and discharging process, reduce the interference of polarization effect, and then measure the open circuit voltage of the battery to be tested at the target temperature, which can ensure that an accurate voltage value is obtained, reduce the influence of temperature fluctuations on the charging and discharging process, battery capacity and measurement voltage, effectively reduce the SOC estimation error of the battery to be tested at different temperatures, and obtain a more accurate battery SOC-OCV curve.

[0010] According to another specific embodiment of the present invention, the calibrated capacity is determined in the following manner:

[0011] Discharge step: at room temperature, discharge the fully charged battery under test at a constant current until the voltage of the battery under test reaches the discharge cut-off voltage; at the discharge cut-off voltage, discharge the battery under test at a constant voltage until the current of the battery under test reaches the cut-off current;

[0012] Charging step: charging the discharged battery under test at room temperature with a constant current until the voltage of the battery under test reaches the charging cut-off voltage, and charging the battery under test at a constant voltage under the charging cut-off voltage until the current of the battery under test reaches the cut-off current;

[0013] The charge cut-off voltage is the voltage corresponding to when the battery under test is fully charged, the discharge cut-off voltage is the voltage corresponding to when the battery under test is fully discharged, and the cut-off current is the current corresponding to when the battery under test is fully charged or fully discharged.

[0014] Capacity calibration step: The discharge step and the charge step are performed together multiple times until the discharge capacity of the battery under test in the discharge step and / or the charge capacity in the charge step reaches a stable state, and the calibration capacity is determined according to the discharge capacity during the last discharge step and / or the charge capacity during the last charge step.

[0015] According to another specific embodiment of the present invention, the rated capacity includes a rated capacity in a charging direction and a rated capacity in a discharging direction;

[0016] When the charge and discharge operation is charging, the capacity required to perform the charge and discharge operation on the battery to be tested to reach the target battery state of charge is determined according to the target battery state of charge and the calibrated capacity of the battery to be tested in the charging direction at room temperature, and the determined battery SOC-OCV curve is the battery SOC-OCV curve in the charging direction;

[0017] When the charge and discharge operation is discharge, the capacity required to perform charge and discharge operations on the battery to be tested to reach the target battery state of charge is determined based on the target battery state of charge and the calibrated capacity of the battery to be tested in the discharge direction at room temperature, and the determined battery SOC-OCV curve is the battery SOC-OCV curve in the discharge direction.

[0018] According to another specific embodiment of the present invention, the rated capacity is further determined by:

[0019] The discharged battery under test is charged with a constant current at the cut-off current until the voltage of the battery under test reaches the charge cut-off voltage, and the actual charging capacity is obtained;

[0020] Determine whether the difference between the actual charge capacity and the charge capacity at the last execution of the charging step is within the allowable charging error range; if so, determine the charge capacity at the last execution of the charging step as the calibration capacity in the charging direction, and the calibration capacity in the charging direction is used to determine the battery SOC-OCV curve in the charging direction; if not, re-execute the capacity determination step until the difference between the actual charge capacity and the charge capacity at the last execution of the charging step is within the allowable charging error range;

[0021] and / or, performing constant current discharge on the fully charged battery under test with a cut-off current until the voltage of the battery under test reaches the discharge cut-off voltage, thereby obtaining the actual discharge capacity;

[0022] Determine whether the difference between the actual discharge capacity and the discharge capacity when the discharge step was last executed is within the allowable discharge error range; if so, determine the discharge capacity when the discharge step was last executed as the calibrated capacity in the discharge direction, and the calibrated capacity in the discharge direction is used to determine the battery SOC-OCV curve in the discharge direction; if not, re-execute the constant capacity step until the difference between the actual discharge capacity and the discharge capacity when the discharge step was last executed is within the allowable discharge error range.

[0023] According to another specific embodiment of the present invention, the cut-off current is C / 150 to C / 50, wherein C is the rated capacity of the battery to be tested.

[0024] According to another specific embodiment of the present invention, charging and discharging operations are performed on the battery to be tested at room temperature until the battery to be tested reaches a current target battery state of charge, specifically including:

[0025] When the target battery state of charge of the battery under test has not reached the preset terminal battery state of charge, charging and discharging the battery under test in a constant current manner at room temperature until the battery under test reaches the current target battery state of charge;

[0026] When the target battery state of charge of the battery under test reaches a preset terminal battery state of charge, the battery under test is charged and discharged in a CCCV (constant current constant voltage) manner at room temperature until the battery under test reaches the current target battery state of charge;

[0027] Among them, when the charge and discharge operation is charging, the preset final battery state of charge is the battery state of charge corresponding to the end of charging; when the charge and discharge operation is discharging, the preset final battery state of charge is the battery state of charge corresponding to the end of discharging.

[0028] According to another specific embodiment of the present invention, when the battery to be tested is subjected to constant current charging and / or discharging at room temperature, the current used is C / 10 to C / 3, where C is the rated capacity of the battery to be tested.

[0029] According to another specific embodiment of the present invention, placing the battery under test at a target temperature and obtaining a voltage value corresponding to a current target battery state of charge of the battery under test at the target temperature specifically includes:

[0030] The battery to be tested is placed at a target temperature and left to stand for a preset time, and a voltage value corresponding to the current target battery state of charge of the battery to be tested at the target temperature is obtained;

[0031] The preset time is [|T-T0|*0.1+3] to [|T-T0|*0.1+9] hours, where T is the target temperature and T0 is the room temperature.

[0032] In a second aspect, an embodiment of the present invention discloses a battery SOC-OCV curve testing device, comprising:

[0033] a detection module configured to perform charge and discharge operations on a battery under test at room temperature until the battery under test reaches a current target battery state of charge, place the battery under test at a target temperature, obtain a voltage value corresponding to the current target battery state of charge of the battery under test at the target temperature, and continue to perform charge and discharge operations on the battery under test at the current target battery state of charge at room temperature so that the battery under test reaches a target battery state of charge different from the current target battery state of charge, until a plurality of voltage values ​​corresponding to a plurality of different target battery states of charge at the target temperature are obtained;

[0034] The charge and discharge operation includes charging or discharging. The capacity required for the battery to be tested to achieve a target battery state of charge by performing the charge and discharge operation is determined based on the target battery state of charge and the calibrated capacity of the battery to be tested at room temperature. The calibrated capacity is the capacity of the battery to be tested when it reaches a stable state.

[0035] The curve determination module is used to determine the battery SOC-OCV curve of the battery to be tested at a target temperature based on multiple target battery states of charge and their corresponding multiple voltage values.

[0036] By adopting the above technical solution, in the battery SOC-OCV curve testing device of the present invention, the calibrated capacity of the battery to be tested is determined at room temperature, and charging and discharging are performed at room temperature, which can ensure the accuracy of capacity calibration and the stability of the charging and discharging process, reduce the interference of polarization effect, and then measure the open circuit voltage of the battery to be tested at the target temperature, which can ensure that the accurate voltage value is obtained, reduce the influence of temperature fluctuations on the charging and discharging process, battery capacity and measurement voltage, and effectively reduce the SOC estimation error of the battery to be tested at different temperatures, and the obtained battery SOC-OCV curve is more accurate.

[0037] In a third aspect, an embodiment of the present invention discloses an electronic device comprising a processor and a memory, wherein the memory stores at least one instruction, and when the at least one instruction is executed by the processor, the method for testing the battery SOC-OCV curve in any embodiment of the first aspect is implemented.

[0038] By adopting the above technical solution, when the electronic device executes the battery SOC-OCV curve test method, it determines the calibrated capacity of the battery to be tested at room temperature and performs charging and discharging at room temperature, which can ensure the accuracy of capacity calibration and the stability of the charging and discharging process, reduce the interference of polarization effect, and then measure the open circuit voltage of the battery to be tested at the target temperature, which can ensure that the accurate voltage value is obtained, reduce the impact of temperature fluctuations on the charging and discharging process, battery capacity and measurement voltage, and effectively reduce the SOC estimation error of the battery to be tested at different temperatures, so that the obtained battery SOC-OCV curve is more accurate.

[0039] In a fourth aspect, an embodiment of the present invention discloses a computer-readable storage medium, in which at least one instruction is stored. When the at least one instruction is executed, it implements the battery SOC-OCV curve testing method in any embodiment of the first aspect.

[0040] By adopting the above technical solution, when executing the battery SOC-OCV curve test method, the computer-readable storage medium determines the calibrated capacity of the battery to be tested at room temperature, and performs charging and discharging at room temperature, which can ensure the accuracy of capacity calibration and the stability of the charging and discharging process, reduce the interference of polarization effect, and then measure the open circuit voltage of the battery to be tested at the target temperature, which can ensure that the accurate voltage value is obtained, reduce the impact of temperature fluctuations on the charging and discharging process, battery capacity and measurement voltage, and effectively reduce the SOC estimation error of the battery to be tested at different temperatures, so that the obtained battery SOC-OCV curve is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram showing the process of the battery SOC-OCV curve testing method in an embodiment of the present invention Figure 1 ;

[0042] Figure 2 Schematic diagram showing the process of the battery SOC-OCV curve testing method in an embodiment of the present invention Figure 2 ;

[0043] Figure 3 Schematic diagram showing the process of the battery SOC-OCV curve testing method in an embodiment of the present invention Figure 3 ;

[0044] Figure 4 Schematic diagram showing the process of the battery SOC-OCV curve testing method in an embodiment of the present invention Figure 4 ;

[0045] Figure 5 Schematic diagram showing the process of the battery SOC-OCV curve testing method in an embodiment of the present invention Figure 5 ;

[0046] Figure 6 A schematic diagram showing the structure of a test device for a battery SOC-OCV curve according to an embodiment of the present invention;

[0047] Figure 7 A schematic structural diagram of an electronic device according to an embodiment of the present invention is shown;

[0048] Figure 8 The SOC-OCV curves of the battery in the charging direction and the discharging direction in Example 1 of the present invention are shown;

[0049] Figure 9 The SOC-OCV curves of the battery in the charging direction and the discharging direction in Example 2 of the present invention are shown;

[0050] Figure 10 A schematic diagram showing a comparison of the battery SOC-OCV curves under discharge directions of Example 2 of the present invention and Comparative Example 1 is shown. DETAILED DESCRIPTION

[0051] The following is an explanation of the embodiments of the present invention by specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this embodiment. On the contrary, the purpose of introducing the invention in conjunction with the embodiment is to cover other options or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will contain many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0052] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0053] The terms “first”, “second”, etc. are only used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0054] In the description of this embodiment, it should be noted that, unless otherwise specified or limited, the terms "disposed," "connected," and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this embodiment based on specific circumstances.

[0055] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0056] First, reference Figure 1 The embodiment of the present invention discloses a method for testing a battery SOC-OCV curve, which specifically includes the following steps:

[0057] S1: performing charge and discharge operations on the battery to be tested at room temperature until the battery to be tested reaches a current target battery state of charge, placing the battery to be tested at a target temperature, obtaining a voltage value corresponding to the current target battery state of charge of the battery to be tested at the target temperature, and continuing to perform charge and discharge operations on the battery to be tested at the current target battery state of charge at room temperature so that the battery to be tested reaches a target battery state of charge different from the current target battery state of charge, until multiple voltage values ​​corresponding to multiple different target battery states of charge at the target temperature are obtained.

[0058] The charge-discharge operation includes charging or discharging. When measuring the battery SOC-OCV curve, if the curve is measured in the charging direction, the charge-discharge operation is charging; if the curve is measured in the discharging direction, the charge-discharge operation is discharging. When measuring the SOC-OCV curve of a single battery, the charge-discharge operation is always charging or always discharging, and not both charging and discharging. The room temperature is, for example, 25±2°C, or 23-27°C. The battery to be tested is, for example, a lithium-ion battery.

[0059] The capacity required to charge and discharge the battery under test to achieve a target battery state of charge (SOC) is determined based on the target battery state of charge (SOC) and the calibrated capacity of the battery under test at room temperature. The calibrated capacity is the capacity of the battery under test when it reaches a steady state. For example, in the charging direction, the product of the target battery state of charge (SOC) and the calibrated capacity is the capacity required to charge and discharge the battery under test to achieve the target battery state of charge (SOC). In the discharging direction, the product of the target battery state of charge (SOC) and the calibrated capacity is first calculated. The difference between the calibrated capacity and this product is the capacity required to charge and discharge the battery under test to achieve the target battery state of charge (SOC). In other embodiments, the charge and discharge operations may be continued with a fixed capacity each time for the battery to be tested. For example, when the voltage corresponding to the target battery state of charge is measured at every 2% SOC interval (for example, the first measurement is the voltage corresponding to the SOC of 6%, the second measurement may be the voltage corresponding to the SOC of 8%, and so on). Each time the charge and discharge operations are continued for the battery to be tested, the capacity that needs to be charged or discharged when the battery to be tested changes from the current target battery state of charge to the next target battery state of charge is 2% of the calibrated capacity.

[0060] S2: Determine a battery SOC-OCV curve of the battery to be tested at a target temperature according to the multiple target battery states of charge and the multiple corresponding voltage values.

[0061] Through the above technical solution, in the test method of the battery SOC-OCV curve of the present invention, the calibrated capacity of the battery to be tested is determined at room temperature, and charging and discharging are performed at room temperature, which can ensure the accuracy of the capacity calibration and the stability of the charging and discharging process, reduce the interference of the polarization effect, and help ensure that the capacity actually charged or discharged by the battery to be tested meets the predetermined capacity. Among them, since the capacity required for the battery to be tested to achieve the target battery state of charge is determined according to the target battery state of charge and the calibrated capacity of the battery to be tested at room temperature, when the battery to be tested is charged and discharged at room temperature according to the required capacity calculated above, it can also ensure that the battery to be tested can actually reach the target battery state of charge, reducing the error caused by the battery capacity change at the target temperature. Subsequently, the open circuit voltage (OCV) of the battery to be tested is measured at the target temperature, which can ensure that the voltage value corresponding to the accurate target battery state of charge (SOC) is obtained, which can reduce the influence of temperature fluctuations on the charging and discharging process, battery capacity and measured voltage, and can effectively reduce the SOC estimation error of the battery to be tested at different temperatures, and the obtained battery SOC-OCV curve is more accurate.

[0062] In the above embodiment, the calibrated capacity is specifically determined by the following method:

[0063] S3: Discharge step: At room temperature, the fully charged battery to be tested is discharged at a constant current until the voltage of the battery to be tested reaches the discharge cut-off voltage. At the discharge cut-off voltage, the battery to be tested is discharged at a constant voltage until the current of the battery to be tested reaches the cut-off current.

[0064] S4: Charging step: charging the discharged battery under test at room temperature at a constant current until the voltage of the battery under test reaches the charging cut-off voltage, and charging the battery under test at a constant voltage at the charging cut-off voltage until the current of the battery under test reaches the cut-off current.

[0065] The charge cutoff voltage is the voltage corresponding to when the battery under test is fully charged, and the discharge cutoff voltage is the voltage corresponding to when the battery under test is completely discharged. For example, for a lithium iron battery, the charge cutoff voltage may be 3.65V or 3.8V, and the discharge cutoff voltage may be 2.0V or 2.5V; for a ternary lithium battery, the charge cutoff voltage may be 4.2V or 4.3V, and the discharge cutoff voltage may be 2.5V or 2.7V. The cutoff current is the current corresponding to when the battery under test is fully charged or completely discharged.

[0066] Specifically, the battery to be tested in any state can be left to stand at room temperature for a period of time, such as 1 hour, to allow the battery to be tested to reach thermal equilibrium, and then the battery to be tested is discharged in a constant current constant voltage (CCCV) manner at a current of C / 3 (where C is the rated capacity of the battery to be tested) to the discharge cut-off voltage and cut-off current, that is, the battery to be tested is first discharged at a constant current of C / 3 until the voltage of the battery to be tested reaches the discharge cut-off voltage, and then the battery to be tested is discharged at a constant voltage at the discharge cut-off voltage until the current of the battery to be tested reaches the cut-off current, which can be considered to be completely discharged. Then, the battery to be tested is left to stand for 30 minutes to allow the battery to be tested to reach thermal equilibrium. Subsequently, the above steps S3 and S4 can be performed on the battery to be tested. Among them, thermal balance can mean that the difference between the temperature of the battery to be tested and the ambient temperature is kept within 2°C within a preset thermal balance time, and the preset thermal balance time is greater than 30 minutes, which can be further determined according to actual needs, for example, it can be 30 minutes to 1 hour. When the battery to be tested is at room temperature, the ambient temperature refers to the room temperature; when the battery to be tested is at the target temperature, the ambient temperature refers to the target temperature.

[0067] For example, in steps S3 and S4, when constant current charging or constant current discharging is performed, the current used may be C / 3. After step S3 or S4 is completed, the battery to be tested may be allowed to stand at room temperature for a period of time to achieve thermal equilibrium before proceeding to subsequent steps. This can reduce the impact of temperature changes during the battery charging and discharging process and help obtain a more accurate calibrated capacity.

[0068] S5: Capacity determination step: The discharge step and the charge step are performed together multiple times until the discharge capacity of the battery under test in the discharge step and / or the charge capacity in the charge step reaches a stable state, and the calibration capacity is determined according to the discharge capacity during the last discharge step and / or the charge capacity during the last charge step.

[0069] Among them, there is no limitation on the execution order of steps S3 and S4, and step S3 can be executed first, and then step S4, or step S4 can be executed first, and then step S3. In step S5, the discharge step and the charge step are executed together multiple times, specifically referring to performing multiple charge and discharge cycles on the battery to be tested. During the cycle, each time step S3 or S4 is executed, the battery to be tested must first be allowed to reach thermal equilibrium at room temperature, and then the subsequent steps are performed. For example, after executing step S3, the battery to be tested is allowed to stand at room temperature for 30 minutes to reach thermal equilibrium, and then step S4 is executed. When the number of charge and discharge cycles reaches the preset number, it can be considered that the discharge capacity of the battery to be tested in the discharge step and / or the charge capacity in the charge step has reached a stable state. The preset number can be, for example, 3-5 times, and more specifically, it can be three times, which helps to obtain accurate calibration capacity in a shorter time.

[0070] Furthermore, in each of the above embodiments, the calibrated capacity includes the calibrated capacity in the charging direction and the calibrated capacity in the discharging direction. When the charge-discharge operation in step S1 is charging, the capacity required for performing charge-discharge operations on the battery to be tested to reach the target battery state of charge is determined based on the target battery state of charge and the calibrated capacity of the battery to be tested in the charging direction at room temperature, and the determined battery SOC-OCV curve is the battery SOC-OCV curve in the charging direction. When the charge-discharge operation in step S1 is discharging, the capacity required for performing charge-discharge operations on the battery to be tested to reach the target battery state of charge is determined based on the target battery state of charge and the calibrated capacity of the battery to be tested in the discharging direction at room temperature, and the determined battery SOC-OCV curve is the battery SOC-OCV curve in the discharging direction.

[0071] Using different calibration capacities for battery SOC-OCV curves in different directions can reduce the impact of different charging and discharging efficiencies. When subsequently measuring the voltage corresponding to the target battery state of charge of the battery to be tested, the adjustment of the battery state of charge of the battery to be tested will be more precise and more in line with the target battery state of charge to be achieved, and the obtained battery SOC-OCV curve will be more accurate.

[0072] Furthermore, in the above embodiments, the calibrated capacity is also determined by the following method:

[0073] In the charging direction, refer to Figure 2 , the specific steps to determine the calibration capacity are as follows:

[0074] S01: The discharged battery to be tested is charged at a constant current with a cut-off current until the voltage of the battery to be tested reaches the charging cut-off voltage, thereby obtaining the actual charging capacity.

[0075] S02: Determine whether the difference between the actual charging capacity and the charging capacity when the charging step is last performed is within the charging allowable error range.

[0076] If yes, then S03: determine the charging capacity when the charging step is last executed as the calibrated capacity in the charging direction, and the calibrated capacity in the charging direction is used to determine the battery SOC-OCV curve in the charging direction.

[0077] If not, then S04: re-execute the constant capacity step until the difference between the actual charging capacity and the charging capacity when the charging step was last executed is within the charging allowable error range.

[0078] For example, the allowable charging error range may be a relative difference threshold range of the actual charge capacity between two adjacent constant current charges to the cut-off voltage. In this embodiment, the ratio of the difference between the actual charge capacity of two adjacent charges to the actual charge capacity of the previous charge may be compared to determine whether it is within the allowable charging error range. The allowable charging error range may be, for example, 0.1%-0.5%.

[0079] In the discharge direction, refer to Figure 3 , the specific steps to determine the calibration capacity are as follows:

[0080] S11: performing constant current discharge on the fully charged battery to be tested with a cut-off current until the voltage of the battery to be tested reaches the discharge cut-off voltage, thereby obtaining the actual discharge capacity.

[0081] S12: Determine whether the difference between the actual discharge capacity and the discharge capacity when the discharge step is last performed is within the discharge tolerance range.

[0082] If yes, then S13: determine the discharge capacity when the discharge step is last performed as the calibrated capacity in the discharge direction, and the calibrated capacity in the discharge direction is used to determine the battery SOC-OCV curve in the discharge direction.

[0083] If not, then S14: re-execute the constant capacity step until the difference between the actual discharge capacity and the discharge capacity when the discharge step was last executed is within the discharge tolerance range.

[0084] For example, the discharge tolerance range may be a relative difference threshold value between two adjacent constant current discharges to the cutoff voltage. In this embodiment, the ratio of the difference between the actual discharge capacities of the two adjacent discharges to the actual discharge capacity of the previous discharge may be compared to determine whether it is within the discharge tolerance range. The discharge tolerance range may be, for example, 0.1%-0.5%.

[0085] In step S01 and step S11, the cutoff current used is consistent with the cutoff current of the aforementioned steps S3 and S4, which helps to keep the capacity of the battery under test consistent during charging or discharging operations and unify the standards.

[0086] Through the above technical solution, when determining the calibrated capacity in the charging direction and the discharging direction, the calibrated capacity obtained in the aforementioned step S5 can also be verified, thereby ensuring the accuracy and stability of the obtained calibrated capacity, and further helping to improve the accuracy of the battery SOC-OCV curves obtained in different directions.

[0087] Furthermore, in each of the above embodiments, the cutoff current is C / 150 to C / 50, where C is the rated capacity of the battery under test. Using a cutoff current within this range can more accurately adjust the battery state of charge of the battery under test to the target battery state of charge, reduce the impact of battery polarization during the charge and discharge process of the battery under test, and improve the accuracy of the obtained battery SOC-OCV curve. For example, the cutoff current can be C / 100, which not only ensures the accuracy of adjusting the battery SOC, but also helps shorten the time it takes to test and obtain the battery SOC-OCV curve.

[0088] In each of the above embodiments, after the battery to be tested has been capped, the discharged battery to be tested can be subjected to constant current charging at room temperature with a cutoff current until the voltage of the battery to be tested reaches the charging cutoff voltage. The battery to be tested is then allowed to stand for a period of time to allow the battery to reach thermal equilibrium at room temperature, for example, for 6 hours. The battery to be tested is then subjected to constant current discharge with a cutoff current until the capacity previously charged during constant current charging is discharged. The battery to be tested is then allowed to stand at the target temperature for (t+6) hours, and the voltage of the battery to be tested at this time is measured to obtain the OCV of the battery to be tested. The OCV at this time is the OCV corresponding to a SOC of 0% for the battery to be tested in the discharge direction. By discharging the battery to release the capacity previously charged during constant current charging and then measuring the OCV, it helps to ensure that the battery to be tested is in a precise state of 0% SOC before being transferred to the target temperature, thereby obtaining the corresponding accurate OCV.

[0089] In other embodiments, after the battery to be tested is capacitated, the fully charged battery to be tested can be discharged at a cutoff current at room temperature until the voltage of the battery to be tested reaches the discharge cutoff voltage. The battery to be tested is allowed to stand for a period of time to allow the battery to reach thermal equilibrium at room temperature, for example, for 6 hours. The battery to be tested is then charged at a cutoff current until it reaches the capacity discharged during the previous constant current discharge. The battery to be tested is then placed at the target temperature and allowed to stand for (t+6) hours. The voltage of the battery to be tested at this time is measured to obtain the OCV of the battery to be tested. The OCV at this time is the OCV corresponding to the SOC of the battery to be tested being 100% in the charging direction. By charging the battery to the capacity discharged during the previous constant current discharge and then measuring the OCV, it helps to ensure that the battery to be tested is in an accurate state of 100% SOC before being transferred to the target temperature, thereby obtaining the corresponding accurate OCV.

[0090] Where t is [(T-T0)*0.1-3] to [(T-T0)*0.1+3] hours, T is the target temperature, and T0 is room temperature. This method can quickly determine the rest time required for the battery under test to reach thermal equilibrium after each charge or discharge operation at different temperatures. This avoids the time loss caused by repeated testing to determine whether the battery under test has reached thermal equilibrium, helping to improve curve testing efficiency.

[0091] Furthermore, in the above embodiments, referring to Figure 4 In the aforementioned step S1, charging and discharging operations are performed on the battery to be tested at room temperature until the battery to be tested reaches the current target battery state of charge, specifically including:

[0092] S101 : When the target battery state of charge of the battery under test has not reached a preset terminal battery state of charge, charging and discharging the battery under test in a constant current manner at room temperature until the battery under test reaches the current target battery state of charge.

[0093] Specifically, the battery to be tested may be allowed to stand at room temperature for t hours to allow the battery to reach thermal equilibrium at room temperature, and then the battery to be tested may be charged and discharged at room temperature in a constant current manner until the battery to be tested reaches the current target battery state of charge.

[0094] S102 : When the target battery state of charge of the battery under test reaches a preset terminal battery state of charge, the battery under test is charged and discharged in a CCCV (constant current constant voltage) manner at room temperature until the battery under test reaches the current target battery state of charge.

[0095] The CCCV (constant current constant voltage) method refers to first performing a constant current charge and discharge operation on the battery to be tested to make the battery to be tested reach a certain voltage, and then performing a constant current charge and discharge operation on the battery to be tested at a certain voltage.

[0096] When the charge / discharge operation is charging, the preset final battery state of charge is the battery state of charge corresponding to the end of charging. For example, when the SOC of the battery under test reaches 95%, it can be considered that the target battery state of charge of the battery under test has reached the preset final battery state of charge. When the SOC of the battery under test continues to rise from 95%, charging is switched to the CCCV (constant current constant voltage) method.

[0097] When the charge / discharge operation is discharge, the preset final battery state of charge is the battery state of charge corresponding to the end of discharge. For example, when the SOC of the battery under test reaches 5%, it can be considered that the target battery state of charge of the battery under test has reached the preset final battery state of charge. When the SOC of the battery under test continues to decrease from 5%, discharge is switched to CCCV (constant current constant voltage) mode.

[0098] Through the above technical solution, when the target battery state of charge of the battery to be tested reaches the preset terminal battery state of charge, continuing to perform charge and discharge operations in a constant current manner may cause the actual charge and discharge capacity of the battery to be tested to be difficult to reach the predetermined capacity, and then the battery to be tested will find it difficult to reach the target battery state of charge. At this time, switching to the CCCV (constant current constant voltage) method for charge and discharge operations will help ensure that the actual charge and discharge capacity of the battery to be tested is closer to the predetermined capacity, thereby ensuring that the battery to be tested can reach the target battery state of charge, and the obtained battery SOC-OCV curve is more accurate.

[0099] In the above embodiments, when the battery under test is charged and / or discharged at room temperature using a constant current, the current used is C / 10 to C / 3, where C is the rated capacity of the battery under test. The charge and discharge rate also has an impact on adjusting the SOC of the battery under test. By controlling the current during constant current charging and discharging, that is, controlling the charge and discharge rate to maintain a low charge and discharge rate, the SOC of the battery under test can be adjusted more accurately, ensuring that the SOC of the battery under test reaches the target battery state of charge. For example, the current used can be C / 5.

[0100] The curve testing method in the existing technology is easily affected by the charge and discharge rate and temperature during the adjustment of the battery SOC. In particular, the impedance of the iron-lithium battery will increase significantly at low temperatures, which is not conducive to the precise adjustment of the battery SOC. The actual battery SOC-OCV curve obtained is not accurate enough.

[0101] By combining the use of a small rate to charge and discharge the battery under test, and when the SOC of the battery under test reaches the preset final battery state of charge, the charge and discharge operation is changed from a constant current mode to a CCCV (constant current constant voltage) mode, the accuracy of adjusting the SOC of the battery under test during the test can be further guaranteed, and the SOC of the battery under test can be guaranteed to actually reach the target battery state of charge, thereby reducing the time wasted due to repeated testing caused by inadequate SOC adjustment due to capacity attenuation during the test, and the resulting battery SOC-OCV curve is more accurate.

[0102] Furthermore, in the above embodiments, referring to Figure 5 In the aforementioned step S1, placing the battery under test at the target temperature and obtaining the voltage value corresponding to the current target battery state of charge of the battery under test at the target temperature specifically includes:

[0103] S103: placing the battery to be tested at a target temperature and leaving it to stand for a preset time, and obtaining a voltage value corresponding to a current target battery state of charge of the battery to be tested at the target temperature.

[0104] The preset time is [|T-T0|*0.1+3] to [|T-T0|*0.1+9] hours, T is the target temperature, T0 is the room temperature, and |T-T0| represents the absolute value of the calculated target temperature and the room temperature.

[0105] When testing at different temperatures, by using the above method to calculate the preset time and adjust the temperature, the battery to be tested can be more accurately made to reach the required temperature, avoiding the time loss caused by repeated testing to determine whether the battery to be tested has reached a thermal equilibrium state, which helps to improve the efficiency of curve testing.

[0106] To facilitate understanding of the steps in the above-mentioned testing method, more specific embodiments are described below, but the protection scope of the present invention is not limited to these embodiments.

[0107] Example 1: The target temperature is 25° C., and the battery SOC-OCV curves of the battery under test in the charging direction and the discharging direction are measured at the target temperature. Wherein, the room temperature is not 25° C.

[0108] At room temperature, the battery to be tested was allowed to stand for 1 hour, and then the battery to be tested was discharged at a constant current and constant voltage at a current of C / 3, with a discharge cut-off voltage of 2.5V and a cut-off current of C / 100. The battery to be tested was then allowed to stand for 30 minutes at room temperature.

[0109] Charging steps: The battery to be tested is charged with constant current and constant voltage at a current of C / 3, with a charging cut-off voltage of 3.8V and a cut-off current of C / 100. The battery to be tested is then left to stand at room temperature for 30 minutes.

[0110] Discharge steps: The battery to be tested is discharged at a constant current and constant voltage with a current of C / 3, a discharge cut-off voltage of 2.5V, and a cut-off current of C / 100. The battery to be tested is then left to stand at room temperature for 30 minutes.

[0111] Constant capacity step: cycle the above charging and discharging steps for 3 times (i.e., the charging step is performed 3 times, and the discharging step is performed 3 times), and the discharge capacity in the third discharge step is taken as the calibration capacity C in the discharge direction. rpt1 , take the charging capacity in the third charging step as the calibration capacity C in the charging direction rpt2 .

[0112] When testing the battery SOC-OCV curve in the discharge direction, the battery under test is charged at a constant current of C / 100 at room temperature until the voltage of the battery under test reaches the charge cut-off voltage of 3.8V. The battery is then left to stand at room temperature for 6 hours. The battery under test is then discharged at a constant current of C / 100, and the charging capacity of the battery under test is released at a current of C / 100. The battery under test is left to stand at 25°C for 6 hours, and the OCV is recorded. The OCV at this time is the open circuit voltage (OCV) corresponding to the target battery state of charge of 0% in the discharge direction.

[0113] The first test step: let the battery under test stand for 30 minutes at room temperature until it reaches room temperature, and then discharge the battery under test at a constant current of C / 5 at room temperature until 2% C rpt1 The battery to be tested is placed at 25°C for 6 hours and the OCV is recorded. The first test step is repeated 46 times to obtain multiple target battery states of charge and their corresponding voltage values.

[0114] The second test step: let the battery under test stand for 30 minutes at room temperature until the battery under test reaches room temperature, and discharge the battery under test in a constant current constant voltage (CCCV) mode at room temperature with a current of C / 5 until 2% C is released. rpt1 The battery to be tested is placed at 25°C for 6 hours and the OCV is recorded. The second test step is repeated three times to obtain multiple target battery states of charge and their corresponding voltage values.

[0115] According to the multiple target battery states of charge and their corresponding voltage values ​​obtained in the first and second test steps, a battery SOC-OCV curve corresponding to the discharge direction of the battery to be tested at 25° C. can be obtained.

[0116] When testing the battery SOC-OCV curve under the charging direction, first let the battery under test stand at room temperature for 30 minutes to wait for the battery under test to reach room temperature. At room temperature, discharge the battery under test at a constant current of C / 100 until the voltage of the battery under test reaches the discharge cut-off voltage of 2.5V. Let it stand at room temperature for 6 hours, and then charge the battery under test at a constant current of C / 100 until the discharge capacity of the battery under test is reached by constant current discharge at a current of C / 100. Let the battery under test stand at 25°C for 6 hours, and record the OCV. The OCV at this time is the open circuit voltage (OCV) corresponding to the target battery state of charge of 100% under the charging direction.

[0117] The third test step: let the battery under test stand for 30 minutes at room temperature until it reaches room temperature, and then charge the battery under test at a constant current of C / 5 at room temperature until it reaches 2% C rpt2The battery to be tested is placed at 25°C for 6 hours and the OCV is recorded. The third test step is repeated 46 times to obtain multiple target battery states of charge and their corresponding voltage values.

[0118] The fourth test step: let the battery under test stand for 30 minutes at room temperature until the battery under test reaches room temperature, and then charge the battery under test in a constant current constant voltage (CCCV) mode at room temperature with a current of C / 5 until it reaches 2% C rpt2 The battery to be tested is placed at 25°C for 6 hours and the OCV is recorded. The fourth test step is repeated three times to obtain multiple target battery states of charge and their corresponding voltage values.

[0119] According to the multiple target battery SOCs and their corresponding voltage values ​​obtained in the third and fourth test steps, a battery SOC-OCV curve corresponding to the charging direction of the battery to be tested at 25° C. can be obtained.

[0120] In Example 1, the battery SOC-OCV curve corresponding to the charging direction and the battery SOC-OCV curve corresponding to the discharging direction of the battery under test at 25°C are as follows: Figure 8 As shown. Among them, Figure 8 The horizontal axis is the depth of discharge DOD. The battery's SOC can be converted using the formula SOC=1-DOD. Figure 8 The curve shown is one form of expression of the battery SOC-OCV curve.

[0121] Example 2: The target temperature is -20°C, and the battery SOC-OCV curves of the battery to be tested in the charging direction and the discharging direction are measured at the target temperature.

[0122] At room temperature, the battery to be tested was allowed to stand for 1 hour, and then the battery to be tested was discharged at a constant current and constant voltage at a current of C / 3, with a discharge cut-off voltage of 2.5V and a cut-off current of C / 100. The battery to be tested was then allowed to stand for 30 minutes at room temperature.

[0123] Charging steps: The battery to be tested is charged with constant current and constant voltage at a current of C / 3, with a charging cut-off voltage of 3.8V and a cut-off current of C / 100. The battery to be tested is then left to stand at room temperature for 30 minutes.

[0124] Discharge steps: The battery to be tested is discharged at a constant current and constant voltage with a current of C / 3, a discharge cut-off voltage of 2.5V, and a cut-off current of C / 100. The battery to be tested is then left to stand at room temperature for 30 minutes.

[0125] Constant capacity step: cycle the above charging and discharging steps for 3 times (i.e., the charging step is performed 3 times, and the discharging step is performed 3 times), and the discharge capacity in the third discharge step is taken as the calibration capacity C in the discharge direction. rpt1 , take the charging capacity in the third charging step as the calibration capacity C in the charging direction rpt2 .

[0126] When testing the battery SOC-OCV curve in the discharge direction, the battery under test is charged at a constant current of C / 100 at room temperature until the voltage of the battery under test reaches the charge cut-off voltage of 3.8V. The battery is then left to stand at room temperature for 6 hours. The battery under test is then discharged at a constant current of C / 100 to release the charging capacity of the battery under test when charged at a constant current of C / 100. The battery under test is left to stand at -20°C for 12 hours, and the OCV is recorded. The OCV at this time is the open circuit voltage (OCV) corresponding to the target battery state of charge of 0% in the discharge direction.

[0127] The fifth test step: let the battery under test stand for 6 hours at room temperature until it reaches room temperature, and then discharge the battery under test at a constant current of C / 5 at room temperature until 2% C rpt1 The battery to be tested is placed at -20°C for 12 hours and the OCV is recorded. The fifth test step is repeated 46 times to obtain multiple target battery states of charge and their corresponding voltage values.

[0128] The sixth test step: the battery to be tested is left at room temperature for 6 hours until the battery to be tested reaches room temperature, and the battery to be tested is discharged in a constant current constant voltage (CCCV) mode at room temperature with a current of C / 5 until 2% C is released. rpt1 The battery to be tested is placed at -20°C for 12 hours and the OCV is recorded. The sixth test step is repeated three times to obtain multiple target battery states of charge and their corresponding voltage values.

[0129] According to the multiple target battery SOCs and their corresponding voltage values ​​obtained in the fifth and sixth test steps, a battery SOC-OCV curve corresponding to the discharge direction of the battery to be tested at -20°C can be obtained.

[0130] When testing the battery SOC-OCV curve under the charging direction, first let the battery under test stand at room temperature for 6 hours to wait for the battery under test to reach room temperature. At room temperature, discharge the battery under test at a constant current of C / 100 until the voltage of the battery under test reaches the discharge cut-off voltage of 2.5V. Let it stand at room temperature for 6 hours, and then charge the battery under test at a constant current of C / 100 until the discharge capacity of the battery under test is reached by constant current discharge at a current of C / 100. Let the battery under test stand at -20℃ for 12 hours, and record the OCV. The OCV at this time is the open circuit voltage (OCV) corresponding to the target battery state of charge of 100% under the charging direction.

[0131] The seventh test step: let the battery under test stand for 30 minutes at room temperature until it reaches room temperature, and then charge the battery under test at a constant current of C / 5 at room temperature until it reaches 2% C rpt2 The battery to be tested is placed at -20°C for 12 hours and the OCV is recorded. The seventh test step is repeated 46 times to obtain multiple target battery states of charge and their corresponding voltage values.

[0132] The eighth test step: let the battery under test stand for 30 minutes at room temperature until the battery under test reaches room temperature, and then charge the battery under test in a constant current constant voltage (CCCV) mode at room temperature with a current of C / 5 until it reaches 2% C rpt2 The battery to be tested is placed at -20°C for 12 hours and the OCV is recorded. The eighth test step is repeated three times to obtain multiple target battery states of charge and their corresponding voltage values.

[0133] According to the multiple target battery SOCs and their corresponding voltage values ​​obtained in the seventh and eighth test steps, a battery SOC-OCV curve corresponding to the charging direction of the battery to be tested at -20°C can be obtained.

[0134] In Example 2, the battery SOC-OCV curve corresponding to the charging direction and the battery SOC-OCV curve corresponding to the discharging direction of the battery under test at -20°C are obtained as follows: Figure 9 As shown. Among them, Figure 9 The horizontal axis is the depth of discharge DOD. The battery's SOC can be converted using the formula SOC=1-DOD. Figure 9 The curve shown is one form of expression of the battery SOC-OCV curve.

[0135] Comparative Example 1: Taking the discharge direction as an example, the target temperature is -20°C, and the battery SOC-OCV curve of the battery to be tested in the discharge direction at the target temperature is measured. The only difference from the steps of obtaining the battery SOC-OCV curve in the discharge direction of the battery to be tested in Example 2 is that the charging step, the discharging step, and the constant capacity step in Comparative Example 1 are all performed at a target temperature of -20°C, that is, the calibrated capacity of the battery to be tested is obtained at the target temperature of -20°C. When the battery SOC-OCV curve is subsequently tested based on the calibrated capacity, the result obtained is Figure 10 The curve shown by the dashed line is the curve corresponding to the constant volume at -20°C. The SOC-OCV curve of the battery in the discharge direction in Example 2 corresponds to Figure 10 The black solid line in Figure 10 A schematic diagram comparing the SOC-OCV curves of the batteries in Example 2 and Comparative Example 1 under discharge directions shows significant deviations in the curve obtained in Comparative Example 1, particularly when the depth of discharge (DOD) of the battery under test approaches 100%, i.e., when the target state of charge (SOC) of the battery under test approaches 0%. This demonstrates that determining the rated capacity of the battery under test and performing charge and discharge at room temperature ensures the accuracy of the capacity calibration and the stability of the charge and discharge process. This results in a more accurate open-circuit voltage of the battery under test subsequently measured at the target temperature, and ultimately a more precise SOC-OCV curve.

[0136] Second, reference Figure 6 Embodiments of the present invention disclose a battery SOC-OCV curve testing device 1 capable of performing the battery SOC-OCV curve testing method described in any of the embodiments of the first aspect. The battery SOC-OCV curve testing device 1 includes a detection module 11 and a curve determination module 12. The detection module 11 and the curve determination module 12 are connected.

[0137] The detection module 11 is used to perform charge and discharge operations on the battery to be tested at room temperature until the battery to be tested reaches a current target battery state of charge, place the battery to be tested at a target temperature, obtain a voltage value corresponding to the current target battery state of charge of the battery to be tested at the target temperature, and continue to perform charge and discharge operations on the battery to be tested at the current target battery state of charge at room temperature so that the battery to be tested reaches a target battery state of charge different from the current target battery state of charge, until multiple voltage values ​​corresponding to multiple different target battery states of charge at the target temperature are obtained.

[0138] Among them, the charge and discharge operation includes charging or discharging. The capacity required for performing charge and discharge operations on the battery to be tested to reach the target battery state of charge is determined based on the target battery state of charge and the calibrated capacity of the battery to be tested at room temperature. The calibrated capacity is the capacity of the battery to be tested when it reaches a stable state.

[0139] The curve determination module 12 is used to determine a battery SOC-OCV curve of the battery to be tested at a target temperature according to a plurality of target battery states of charge and a plurality of corresponding voltage values.

[0140] By adopting the above technical solution, in the battery SOC-OCV curve testing device 1 of the present invention, the calibrated capacity of the battery to be tested is determined at room temperature, and charging and discharging are performed at room temperature, which can ensure the accuracy of capacity calibration and the stability of the charging and discharging process, reduce the interference of polarization effect, and then measure the open circuit voltage of the battery to be tested at the target temperature, which can ensure that an accurate voltage value is obtained, reduce the influence of temperature fluctuations on the charging and discharging process, battery capacity and measurement voltage, and effectively reduce the SOC estimation error of the battery to be tested at different temperatures, and the obtained battery SOC-OCV curve is more accurate.

[0141] Furthermore, the battery SOC-OCV curve testing device 1 also includes a capacity calibration module (not shown in the figure), which is used to perform steps S3, S4, S5, S01, S02, S03, S04, S11, S12, S13, S14 and related steps in any of the embodiments of the first aspect. The detection module 11 is also used to perform steps S101, S102, S103 and related steps in any of the embodiments of the first aspect.

[0142] Thirdly, reference Figure 7 An embodiment of the present invention discloses an electronic device 2, including a processor 22 and a memory 21. The memory 21 stores at least one instruction, which, when executed by the processor 22, implements the battery SOC-OCV curve testing method described in any of the aforementioned embodiments. The memory 21 may include, for example, a system memory, a fixed non-volatile storage medium, etc. The system memory may store, for example, an operating system, application programs, a boot loader, and other programs.

[0143] By adopting the above technical solution, when the electronic device 2 executes the battery SOC-OCV curve test method, it determines the calibrated capacity of the battery to be tested at room temperature and performs charging and discharging at room temperature, which can ensure the accuracy of capacity calibration and the stability of the charging and discharging process, reduce the interference of polarization effect, and then measure the open circuit voltage of the battery to be tested at the target temperature, which can ensure that the accurate voltage value is obtained, reduce the impact of temperature fluctuations on the charging and discharging process, battery capacity and measurement voltage, and effectively reduce the SOC estimation error of the battery to be tested at different temperatures, and the obtained battery SOC-OCV curve is more accurate.

[0144] In a fourth aspect, an embodiment of the present invention discloses a computer-readable storage medium, in which at least one instruction is stored. When the at least one instruction is executed, it implements the battery SOC-OCV curve testing method in any embodiment of the first aspect.

[0145] By adopting the above technical solution, when executing the battery SOC-OCV curve test method, the computer-readable storage medium determines the calibrated capacity of the battery to be tested at room temperature, and performs charging and discharging at room temperature, which can ensure the accuracy of capacity calibration and the stability of the charging and discharging process, reduce the interference of polarization effect, and then measure the open circuit voltage of the battery to be tested at the target temperature, which can ensure that the accurate voltage value is obtained, reduce the impact of temperature fluctuations on the charging and discharging process, battery capacity and measurement voltage, and effectively reduce the SOC estimation error of the battery to be tested at different temperatures, so that the obtained battery SOC-OCV curve is more accurate.

[0146] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable non-transitory storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0147] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0148] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0149] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0150] Although the present invention has been illustrated and described with reference to certain preferred embodiments thereof, it should be understood by those skilled in the art that the above description is provided as a further detailed description of the present invention in conjunction with specific embodiments thereof, and that the specific implementation of the present invention is not limited to these descriptions. Those skilled in the art may make various changes in form and details, including simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A method for testing a battery SOC-OCV curve, characterized in that: include: performing charge and discharge operations on a battery under test at room temperature until the battery under test reaches a current target battery state of charge, placing the battery under test at a target temperature, obtaining a voltage value of the battery under test corresponding to the current target battery state of charge at the target temperature, and continuing the charge and discharge operations on the battery under test at the current target battery state of charge at room temperature so that the battery under test reaches a target battery state of charge different from the current target battery state of charge, until a plurality of voltage values ​​corresponding to a plurality of different target battery states of charge at the target temperature are obtained; The charge and discharge operation includes charging or discharging, and the capacity required to perform the charge and discharge operation on the battery to be tested to reach the target battery state of charge is determined based on the target battery state of charge and the calibrated capacity of the battery to be tested at room temperature, where the calibrated capacity is the capacity of the battery to be tested when it reaches a stable state; A battery SOC-OCV curve of the battery to be tested at the target temperature is determined according to the multiple target battery states of charge and the multiple voltage values ​​corresponding thereto.

2. The method for testing the battery SOC-OCV curve according to claim 1, wherein: The rated capacity is specifically determined by the following method: Discharging step: discharging the fully charged battery under test at a constant current at room temperature until the voltage of the battery under test reaches a discharge cut-off voltage, and discharging the battery under test at a constant voltage at the discharge cut-off voltage until the current of the battery under test reaches a cut-off current; Charging step: charging the discharged battery under test at room temperature with a constant current until the voltage of the battery under test reaches a charging cut-off voltage, and charging the battery under test at a constant voltage at the charging cut-off voltage until the current of the battery under test reaches the cut-off current; The charge cut-off voltage is the voltage corresponding to when the battery under test is fully charged, the discharge cut-off voltage is the voltage corresponding to when the battery under test is fully discharged, and the cut-off current is the current corresponding to when the battery under test is fully charged or fully discharged. Capacity stabilization step: The discharging step and the charging step are performed together multiple times until the discharge capacity of the battery under test in the discharging step and / or the charging capacity in the charging step reaches a stable state, and the calibrated capacity is determined according to the discharge capacity when the discharging step is last performed and / or the charging capacity when the charging step is last performed.

3. The method for testing the battery SOC-OCV curve according to claim 2, wherein: The rated capacity includes the rated capacity in the charging direction and the rated capacity in the discharging direction; When the charge-discharge operation is charging, the capacity required to perform the charge-discharge operation on the battery to be tested to reach the target battery state of charge is determined according to the target battery state of charge and the calibrated capacity of the battery to be tested in the charging direction at room temperature, and the determined battery SOC-OCV curve is the battery SOC-OCV curve in the charging direction; When the charge and discharge operation is discharge, the capacity required to perform charge and discharge operations on the battery to be tested to achieve the target battery state of charge is determined based on the target battery state of charge and the calibrated capacity of the battery to be tested in the discharge direction at room temperature, and the determined battery SOC-OCV curve is the battery SOC-OCV curve in the discharge direction.

4. The method for testing the battery SOC-OCV curve according to claim 2, wherein: The nominal capacity is also determined by: performing constant current charging on the discharged battery under test with the cut-off current until the voltage of the battery under test reaches the charging cut-off voltage, and obtaining an actual charging capacity; Determine whether the difference between the actual charging capacity and the charging capacity when the charging step was last executed is within the charging tolerance range; if so, determine the charging capacity when the charging step was last executed as the calibration capacity in the charging direction, and the calibration capacity in the charging direction is used to determine the battery SOC-OCV curve in the charging direction; if not, re-execute the capacity determination step until the difference between the actual charging capacity and the charging capacity when the charging step was last executed is within the charging tolerance range; and / or, performing constant current discharge on the fully charged battery to be tested at the cut-off current until the voltage of the battery to be tested reaches the discharge cut-off voltage, thereby obtaining an actual discharge capacity; Determine whether the difference between the actual discharge capacity and the discharge capacity when the discharge step was last executed is within the allowable discharge error range; if so, determine the discharge capacity when the discharge step was last executed as the calibrated capacity in the discharge direction, and the calibrated capacity in the discharge direction is used to determine the battery SOC-OCV curve in the discharge direction; if not, re-execute the constant capacity step until the difference between the actual discharge capacity and the discharge capacity when the discharge step was last executed is within the allowable discharge error range.

5. The method for testing the battery SOC-OCV curve according to claim 2, wherein: The cut-off current is C / 150 to C / 50, where C is the rated capacity of the battery to be tested.

6. The method for testing the battery SOC-OCV curve according to claim 1, wherein: The charging and discharging operations are performed on the battery to be tested at room temperature until the battery to be tested reaches a current target battery state of charge, specifically comprising: When the target battery state of charge of the battery under test has not reached a preset terminal battery state of charge, performing the charge and discharge operations on the battery under test in a constant current manner at room temperature until the battery under test reaches the current target battery state of charge; When the target battery state of charge of the battery under test reaches a preset terminal battery state of charge, performing the charge and discharge operations on the battery under test in a CCCV (constant current constant voltage) manner at room temperature until the battery under test reaches the current target battery state of charge; Among them, when the charge and discharge operation is charging, the preset final battery state of charge is the battery state of charge corresponding to the end of charging; when the charge and discharge operation is discharging, the preset final battery state of charge is the battery state of charge corresponding to the end of discharging.

7. The method for testing the battery SOC-OCV curve according to claim 6, wherein: When the battery to be tested is charged and / or discharged at a constant current at room temperature, the current used is C / 10 to C / 3, where C is the rated capacity of the battery to be tested.

8. The method for testing the battery SOC-OCV curve according to claim 1, wherein: Placing the battery to be tested at a target temperature and obtaining a voltage value corresponding to the current target battery state of charge of the battery to be tested at the target temperature specifically includes: Placing the battery under test at a target temperature and allowing it to stand for a preset time, and obtaining a voltage value corresponding to the current target battery state of charge of the battery under test at the target temperature; The preset time is [|T-T0|*0.1+3] to [|T-T0|*0.1+9] hours, T is the target temperature, and T0 is room temperature.

9. A battery SOC-OCV curve testing device, characterized in that: include: a detection module, configured to perform charge and discharge operations on a battery under test at room temperature until the battery under test reaches a current target battery state of charge, place the battery under test at a target temperature, obtain a voltage value corresponding to the current target battery state of charge of the battery under test at the target temperature, and continue to perform the charge and discharge operations on the battery under test at the current target battery state of charge at room temperature so that the battery under test reaches a target battery state of charge different from the current target battery state of charge, until a plurality of voltage values ​​corresponding to a plurality of different target battery states of charge at the target temperature are obtained; The charge and discharge operation includes charging or discharging, and the capacity required to perform the charge and discharge operation on the battery to be tested to reach the target battery state of charge is determined based on the target battery state of charge and the calibrated capacity of the battery to be tested at room temperature, where the calibrated capacity is the capacity of the battery to be tested when it reaches a stable state; The curve determination module is used to determine the battery SOC-OCV curve of the battery to be tested at the target temperature according to the multiple target battery states of charge and the multiple voltage values ​​corresponding thereto.

10. An electronic device, characterized in that: The electronic device includes a processor and a memory, wherein the memory stores at least one instruction, and when the at least one instruction is executed by the processor, the method for testing the battery SOC-OCV curve according to any one of claims 1 to 8 is implemented.

11. A computer-readable storage medium, characterized in that The computer-readable storage medium stores at least one instruction, and when the at least one instruction is executed, the method for testing the battery SOC-OCV curve according to any one of claims 1 to 8 is implemented.

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