Post-overdischarge state confirmation method, control device, test equipment and medium

Abstract

The invention discloses a post-overdischarge state confirmation method, a control device, test equipment and a medium. The battery device comprises a single battery cell, and the state confirmation method comprises the following steps: acquiring the voltage of the single battery cell after overdischarge; under the condition that the voltage of the single battery cell is smaller than or equal to the deterioration voltage, determining that the state of the battery device is a scrapped state; under the condition that the voltage of the single battery cell is greater than the deterioration voltage, when the maximum charging voltage difference and the maximum discharging voltage difference of the battery device are both in corresponding set ranges, determining that the state of the battery device is a normal state; and when at least one of the maximum charging voltage difference and the maximum discharging voltage difference of the battery device exceeds the corresponding set range, determining that the state of the battery device is a scrapped state. According to the state confirmation method, on one hand, waste caused by scrapping of the normally used battery device can be avoided, and on the other hand, the problems of service life and safety caused by continuous use of the scrapped battery device are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage power supplies, and particularly relates to a method for confirming the state of a battery device after over-discharge, a control device, a test device, and a computer-readable storage medium. Background Art

[0002] In the related art, an energy storage power supply includes a battery pack for storing electric energy. When the battery pack supplies power outward, if the discharge exceeds the lower voltage limit of the battery pack, over-discharge of the battery pack occurs. If the battery pack is directly scrapped after over-discharge, it will cause great waste. If the over-discharged battery pack is directly charged and continued to be used, since the battery has been severely over-discharged, the life and safety of the product will be greatly reduced. Summary of the Invention

[0003] Embodiments of the present invention provide a method for confirming the state of a battery device after over-discharge, a control device, a test device, and a computer-readable storage medium to solve at least one of the above technical problems.

[0004] Embodiments of the present invention provide a method for confirming the state of a battery device after over-discharge. The battery device includes single-cell battery cores, and the state confirmation method includes:

[0005] Obtaining the voltage of the single-cell battery core after over-discharge;

[0006] When the voltage of the single-cell battery core is less than or equal to a deterioration voltage, confirming that the state of the battery device is a scrapped state;

[0007] When the voltage of the single-cell battery core is greater than the deterioration voltage, when both the maximum charge voltage difference and the maximum discharge voltage difference of the battery device are within corresponding set ranges, confirming that the state of the battery device is a normal state; when at least one of the maximum charge voltage difference and the maximum discharge voltage difference of the battery device exceeds the corresponding set range, confirming that the state of the battery device is a scrapped state.

[0008] In the above state confirmation method, the state of the battery device can be confirmed by the voltage of the single-cell battery core and the deterioration voltage, as well as the maximum charge voltage difference and the maximum discharge voltage difference of the battery device. Thus, on the one hand, it can avoid waste caused by scrapping a normally used battery device, and on the other hand, it can avoid problems of life and safety caused by continued use of a scrapped battery device.

[0009] In some embodiments, the state confirmation method includes:

[0010] Obtaining different discharge cut-off voltages;

[0011] Discharge the single battery cell before over-discharge until the voltage of the single battery cell reaches the discharge cut-off voltage, so that the single battery cell is in an over-discharged state;

[0012] After standing the single battery cell after over-discharge for a first set time period, obtain the over-discharge rebound voltage of the single battery cell;

[0013] Determine the deterioration voltage according to the multiple over-discharge rebound voltages corresponding to different discharge cut-off voltages and the performance of the single battery cell after over-discharge.

[0014] In some embodiments, discharging the single battery cell before over-discharge until the voltage of the single battery cell reaches the discharge cut-off voltage, so that the single battery cell is in an over-discharged state includes:

[0015] Perform over-discharge on the single battery cell before over-discharge with a milliamp-level current until the voltage of the single battery cell reaches the discharge cut-off voltage, so that the single battery cell is in an over-discharged state.

[0016] In some embodiments, the performance of the single battery cell after over-discharge includes at least one of the following:

[0017] Whether copper is deposited inside the single battery cell;

[0018] After charging and activating the single battery cell after over-discharge, the residual capacity and recovery capacity of the single battery cell;

[0019] The cycle performance of the single battery cell after charging and activation.

[0020] In some embodiments, the cycle performance of the single battery cell after charging and activation is obtained by testing in an environment of 25 degrees Celsius to 45 degrees Celsius.

[0021] In some embodiments, the state confirmation method includes:

[0022] Charge and activate the single battery cell after over-discharge;

[0023] After the single battery cell is charged and activated, charge and discharge the battery device and obtain the maximum charging pressure difference and the maximum discharging pressure difference of the battery device.

[0024] In some embodiments, the single battery cell is a lithium battery cell, and the deterioration voltage is greater than or equal to 1 volt.

[0025] A control device according to an embodiment of the present invention includes:

[0026] A processor, and;

[0027] A memory stores a computer program which, when executed by the processor, implements the steps of the state confirmation method according to any one of the above embodiments.

[0028] A test device according to an embodiment of the present invention includes the above control device.

[0029] An embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon which, when executed by the processor, implements the steps of the state confirmation method according to any one of the above embodiments.

[0030] The additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0032] Figures 1 to 4 is a flowchart of the state confirmation method according to an embodiment of the present invention;

[0033] Figure 5 is a block diagram of a battery device and a test device according to an embodiment of the present invention;

[0034] Figure 6 is another block diagram of a battery device and a test device according to an embodiment of the present invention.

[0035] MAIN ELEMENT SYMBOL DESCRIPTION:

[0036] Test device 1000, control device 200, memory 210, processor 220, battery device 300, single cell 301. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described by referring to the drawings are exemplary only for explaining the embodiments of the present invention and should not be construed as limiting the embodiments of the present invention.

[0038] Please refer to Figure 1 、 Figure 5 and Figure 6 , an embodiment of the present invention provides a method for confirming the state of a battery device 300 after over-discharge. The battery device 300 includes a single cell 301, and the state confirmation method includes:

[0039] Step S01, obtain the voltage of the single battery cell 301 after over-discharge;

[0040] Step S03, when the voltage of the single battery cell 301 is less than or equal to the deterioration voltage, confirm that the state of the battery device 300 is a scrapped state;

[0041] Step S05, when the voltage of the single battery cell 301 is greater than the deterioration voltage, when both the maximum charging voltage difference and the maximum discharging voltage difference of the battery device 300 are within the corresponding set ranges, confirm that the state of the battery device 300 is a normal state; when at least one of the maximum charging voltage difference and the maximum discharging voltage difference of the battery device 300 exceeds the corresponding set range, confirm that the state of the battery device 300 is a scrapped state.

[0042] In the above state confirmation method, the state of the battery device 300 can be confirmed by the voltage of the single battery cell 301 and the deterioration voltage, as well as the maximum charging voltage difference and the maximum discharging voltage difference of the battery device 300. Thus, on the one hand, it can avoid waste caused by scrapping a normally used battery device 300, and on the other hand, it can avoid the life and safety problems caused by continued use of a scrapped battery device 300.

[0043] Specifically, the battery device 300 may include one or more battery modules for providing voltage and capacity. The battery module may include a plurality of single battery cells 301, and the plurality of single battery cells 301 may be connected in series, parallel, or in a hybrid connection. A hybrid connection means that there are both series and parallel connections among the plurality of single battery cells 301.

[0044] The single battery cell 301 can be a secondary battery, which means that the single battery cell 301 can be activated by charging after discharging and can be used continuously. Optionally, the single battery cell 301 can be a lithium battery cell.

[0045] The deterioration voltage refers to the critical voltage value at which the single battery cell 301 reaches a scrapped state after over-discharge.

[0046] The maximum charging voltage difference refers to the difference between the highest voltage and the lowest voltage among the plurality of single battery cells 301 at each moment when the battery device 300 is charging, and the maximum difference is the maximum value among the plurality of differences.

[0047] The maximum discharging voltage difference refers to the difference between the highest voltage and the lowest voltage among the plurality of single battery cells 301 at each moment when the battery device 300 is discharging, and the maximum difference is the maximum value among the plurality of differences.

[0048] The set range corresponding to the maximum charging voltage difference refers to the difference range allowed between the highest voltage and the lowest voltage among multiple single cells 301 at each moment during the charging process of the battery device 300 to ensure the balance of the battery device 300.

[0049] The set range corresponding to the maximum discharging voltage difference refers to the difference range allowed between the highest voltage and the lowest voltage among multiple single cells 301 at each moment during the discharging process of the battery device 300 to ensure the balance of the battery device 300.

[0050] It can be understood that the battery device 300 may include multiple strings of batteries, and each string of batteries may include multiple single cells 301 connected in series. The upper limit value of the set range corresponding to the maximum charging voltage difference and the upper limit value of the set range corresponding to the maximum charging voltage difference are related to the number of battery strings of the battery device 300. In one example, the number of battery strings of the battery device 300 is less than 15. When charging and discharging with the rated capacity of the battery device 300, the set range corresponding to the maximum charging voltage difference is 0 to 80 millivolts (mV), and the set range corresponding to the maximum discharging voltage difference is 0 to 100 mV. In one example, the number of battery strings of the battery device 300 is greater than or equal to 15 and less than or equal to 30. When charging and discharging with the rated capacity of the battery device 300, the set range corresponding to the maximum charging voltage difference is 0 to 150 mV, and the set range corresponding to the maximum discharging voltage difference is 0 to 200 mV.

[0051] In the related art, an energy storage power supply includes a battery pack for storing electrical energy. When the battery pack supplies power outward, if the discharge exceeds the lower voltage limit of the battery pack, over-discharge of the battery pack occurs. If the battery pack is directly scrapped after over-discharge, it will cause great waste. If the over-discharged battery pack is directly charged and continued to be used, the life and safety of the product may be greatly reduced due to the severe over-discharge of the battery.

[0052] Optionally, in one embodiment, please refer to Figure 5 , the battery device 300 can be electrically connected to the test device 1000. Optionally, in one embodiment, please refer to Figure 6 , the test device 1000 may include the battery device 300, that is, the test device 1000 can be the battery device 300, and the battery device 300 includes a control device 200.

[0053] The test device 1000 may include a control device 200. The control device 200 can obtain the voltage of the single cell 301 and compare the voltage of the single cell 301 with the deteriorated voltage. When the voltage of the single cell 301 is less than or equal to the deteriorated voltage, it is confirmed that the state of the battery device 300 is a scrapped state. When the voltage of the single cell 301 is greater than the deteriorated voltage, the maximum charge voltage difference and the maximum discharge voltage difference of the battery device 300 are obtained. When both the maximum charge voltage difference and the maximum discharge voltage difference of the battery device 300 are within the corresponding set ranges, it is confirmed that the state of the battery device 300 is a normal state; when at least one of the maximum charge voltage difference and the maximum discharge voltage difference of the battery device 300 exceeds the corresponding set range, it is confirmed that the state of the battery device 300 is a scrapped state.

[0054] Optionally, in Figure 6 the embodiment of Figure 5 the test device 1000 includes, but is not limited to, the battery device 300. The control device 200 may include a battery management system (BMS, Battery Management System). In

[0055] In one embodiment, after the state of the battery device 300 is confirmed, the state information of the battery device 300 may be prompted.

[0056] Optionally, in one embodiment, the battery device 300 may include a user interface, and the user interface may display words or signs, or images of the state of the battery device 300.

[0057] Optionally, in one embodiment, the battery device 300 may include indicator lights of different colors, and the battery device 300 may light up the indicator lights corresponding to different states of the battery device 300.

[0058] Optionally, in one embodiment, the battery device 300 may include a buzzer or a voice broadcaster, and the buzzer or the voice broadcaster may prompt the user of the state of the battery device 300.

[0059] Optionally, in one embodiment, the battery device 300 may be communicatively connected to a terminal device, and the battery device 300 may send a prompt message to the terminal device so that the terminal device can prompt the state of the battery device 300. The terminal device may include, but is not limited to, a mobile phone, a tablet computer, a personal computer, a server, a wearable intelligent device (such as a smart helmet, smart glasses, a smart bracelet, a smart watch), etc.

[0060] In some embodiments, in combination with Figure 2 , the state confirmation method includes:

[0061] Step S07, obtain different discharge cut-off voltages;

[0062] Step S09, discharge the single cell 301 before over-discharge until the voltage of the single cell 301 reaches the discharge cut-off voltage, so that the single cell 301 is in an over-discharge state;

[0063] Step S11, after standing the single cell 301 after over-discharge for a first set duration, obtain the over-discharge rebound voltage of the single cell 301;

[0064] Step S13, determine the deterioration voltage according to the multiple over-discharge rebound voltages corresponding to different discharge cut-off voltages and the performance of the single cell 301 after over-discharge.

[0065] In the above embodiment, determining the deterioration voltage according to the multiple over-discharge rebound voltages corresponding to different discharge cut-off voltages and the performance of the single cell 301 after over-discharge can improve the accuracy of the deterioration voltage, so that the state of the battery device 300 can be confirmed more precisely by comparing the voltage of the single cell 301 with the deterioration voltage.

[0066] Specifically, the discharge cut-off voltage refers to the preset minimum voltage threshold during the discharge process of the single cell 301. When the voltage of the single cell 301 drops to the discharge cut-off voltage, the discharge operation is stopped.

[0067] It should be noted that after the discharge of the single cell 301 ends, the voltage will slightly rise due to the weakening of the internal polarization effect.

[0068] In one embodiment, discharging the single cell 301 before over-discharge until the voltage of the single cell 301 reaches the discharge cut-off voltage to make the single cell 301 in an over-discharge state can be carried out as follows: perform a first discharge on the single cell 301 before discharge until the voltage of the single cell 301 reaches the set voltage. After standing the single cell 301 after the first discharge for a second set duration, the voltage of the single cell 301 slightly rises. Then perform a second discharge on the single cell 301 until the voltage of the single cell 301 reaches the set voltage. After standing the single cell 301 after the second discharge for the second set duration, the voltage of the single cell 301 slightly rises. Then perform a third discharge on the single cell 301 again until the voltage of the single cell 301 reaches the set voltage. Repeat the above steps until the number of discharges on the single cell 301 reaches the preset number, so as to obtain the single cell 301 after over-discharge. Among them, the set voltage is equal to the discharge cut-off voltage. Optionally, the second set duration is 1 hour (h) to 3 h, and the preset number is 10 to 30 times.

[0069] The over-discharge rebound voltage refers to the voltage of the single cell 301 after over-discharge. After the single cell 301 after over-discharge is left standing for the first set duration, the voltage of the single cell 301 after over-discharge will slightly rise due to the weakening of the internal polarization effect. The voltage of the single cell 301 after the voltage rise is also the over-discharge rebound voltage. In one example, the discharge cut-off voltage is 0.5 volts (V). After the single cell 301 after over-discharge is left standing for the first set duration, the voltage of the single cell 301 is 1V. Then, the over-discharge rebound voltage of the single cell 301 is 1V.

[0070] It can be understood that by discharging the single cell 301 to different discharge cut-off voltages, multiple corresponding discharge rebound voltages can be obtained.

[0071] Optionally, the first set duration is 18h (hours) to 30h, which can enable the voltage of the over-discharged single cell 301 to rise more fully, so that the obtained deteriorated voltage is more accurate.

[0072] Perform performance tests on the single cells 301 corresponding to different discharge cut-off voltages. Determine the single cells 301 in the scrapped state according to the performance test results. The corresponding over-discharge rebound voltage is also the deteriorated voltage.

[0073] It should be noted that when determining the single cells 301 in the scrapped state according to the performance test results, those skilled in the art can select the corresponding single cells 301 based on different criteria and use the over-discharge rebound voltage of the selected single cells 301 as the deteriorated voltage.

[0074] In one embodiment, the single cell 301 is a lithium iron phosphate battery cell, the first set duration is 24h, and the different discharge cut-off voltages and the corresponding over-discharge rebound voltages are as follows:

[0075]

[0076] In some embodiments, please combine Figure 3 , step S09 includes:

[0077] Step S091, over-discharge the single cell 301 before over-discharge with a current in the milliampere range until the voltage of the single cell 301 reaches the discharge cut-off voltage, so that the single cell 301 is in an over-discharged state.

[0078] In the above embodiment, over-discharging the single cell 301 before over-discharge with a current in the milliampere range can improve the accuracy and reliability of simulating over-discharge, thereby improving the accuracy of the deteriorated voltage.

[0079] Specifically, the current in the milliampere range refers to the current measured in milliamperes (mA).

[0080] A milliamp-level current is used to over-discharge the single cell 301 before over-discharge, that is, a relatively small current is used to over-discharge the single cell 301 before over-discharge, which can make the active material react more fully, reduce the polarization phenomenon, make the discharge of the single cell 301 more sufficient, thereby increasing the over-discharge depth of the over-discharged single cell 301, and further improving the accuracy and reliability of the simulated over-discharge.

[0081] In some embodiments, the performance of the single cell 301 after over-discharge includes at least one of the following:

[0082] Whether copper is deposited inside the single cell 301;

[0083] After charging and activating the over-discharged single cell 301, the residual capacity and recovery capacity of the single cell 301;

[0084] The cycle performance of the single cell 301 after charging and activation.

[0085] In the above embodiments, the deterioration limiting voltage of the single cell 301 can be obtained according to whether copper is deposited inside the single cell 301, the residual capacity and recovery capacity of the single cell 301, and the cycle performance of the single cell 301, which is beneficial to confirming the state of the battery device 300 through the voltage of the single cell 301 and the deterioration voltage.

[0086] Specifically, after the single cell 301 is over-discharged, the copper foil at the negative electrode may be oxidized and dissolved into the electrolyte, and then copper ions may precipitate on the surface of the separator or pass through the separator and precipitate on the surface of the positive electrode.

[0087] After the single cell 301 is over-discharged, the separator and the positive electrode of the single cell 301 can be taken out and tested by an energy dispersive X-ray spectrometer (EDS, Energy Dispersive Spectrometer) to determine whether copper precipitates on the separator and the positive electrode.

[0088] After charging and activating the over-discharged single cell 301, the recovery capacity of the single cell 301 can be tested, that is, the state of charge (SOC, State Of Charge) of the single cell 301 is tested. After charging and activation, after the single cell 301 stands for a third set time period, the residual capacity of the single cell 301 is tested, that is, the state of charge of the single cell 301 is tested. The capacity loss of the single cell 301 can be obtained according to the recovery capacity and the residual capacity. The capacity loss is equal to the recovery capacity minus the residual capacity. Optionally, the third set time period is greater than or equal to 28 days.

[0089] After the single cell 301 after over-discharge is charged and activated, the cycle performance test of the single cell 301 can be carried out, that is, the single cell 301 after over-discharge is subjected to multiple charge and discharge cycles until the state of health (SOH) of the single cell 301 drops to a preset state of health, so as to obtain the corresponding number of cycles. The larger the number of cycles, the better the cycle performance. Optionally, the preset state of health SOH is 70%.

[0090] The cycle performance of the single cell 301 after charging and activation is obtained by testing in an environment at room temperature. Optionally, the temperature range of room temperature is 25 degrees Celsius (°C) to 45 °C.

[0091] In one embodiment, the single cell 301 is a lithium iron phosphate battery cell, the ambient temperature is 45 °C, the restored capacity SOC is 100%, and the preset state of health SOH is 70%. During the cycle test of the single cell 301 after over-discharge, the single cell 301 is charged and discharged at the rated capacity of the battery device 300, and the voltage range of the single cell 301 is 2.5V to 3.6V, that is, during the process of performing multiple charge and discharge cycles on the single cell 301 after over-discharge, the voltage range of the single cell 301 is 2.5V to 3.6V. The different discharge cut-off voltages and the corresponding performance of the single cell 301 after over-discharge are as follows:

[0092] Discharge cut-off voltage 0V 0.5V 1V 1.5V 2V 2.5V Whether copper deposition occurs Copper deposition No copper deposition No copper deposition No copper deposition No copper deposition No copper deposition Cycling performance 100 times 1000 times 1500 times 1500 times 1500 times 1500 times Capacity loss 5％ 3％ 2％ 2％ 2％ 2％

[0093] In one embodiment, the discharged single cell 301 can be charged and activated to repair the over-discharged single cell 301. Charging and activating the discharged single cell 301 includes the steps carried out in the following order:

[0094] 1) Using the first constant charging parameter, charge the single cell 301 to the lower limit voltage;

[0095] 2) Using the second constant charging parameter, charge the single cell 301 to the first voltage, and the first voltage is greater than the lower limit voltage;

[0096] 3) Using the third constant charging parameter, charge the single cell 301 to the second voltage, and the second voltage is greater than the first voltage;

[0097] Among them, the third constant charging parameter is greater than the second constant charging parameter, the second constant charging parameter is greater than the first constant charging parameter, and the third constant charging parameter is less than the normal charging parameter of the single cell 301.

[0098] Optionally, the first constant charging parameter is 0.01C to 0.05C, or 0.01P to 0.05P; the second constant charging parameter is 0.05C to 0.1C, or 0.05P to 0.1P; the third constant charging parameter is 0.1C to 0.2C, or 0.1P to 0.2P. The first voltage is the voltage corresponding to 10% to 30% of the full charge of the single cell 301, the second voltage is the full charge voltage of the single cell 301, and the lower limit voltage refers to the lowest allowable discharge voltage value set to avoid over-discharge under normal operating conditions of the single cell 301. Herein, C is the rated capacity of the battery device 300, and P is the rated power of the battery device 300. Different single cells 301 have different lower limit voltages. In one example, the lower limit voltage of the lithium iron phosphate battery cell is 2.5V; the lower limit voltage of the ternary lithium battery cell is 4.2V.

[0099] In some embodiments, the cycle performance of the single cell 301 after charging activation is obtained by testing in an environment of 25 degrees Celsius to 45 degrees Celsius.

[0100] In the above embodiments, the cycle performance of the single cell 301 after charging activation is obtained by testing in an environment of 25 degrees Celsius to 45 degrees Celsius, which can improve the accuracy of the deterioration voltage, so that the state of the battery device 300 confirmed according to the single cell 301 and the deterioration voltage is more accurate.

[0101] Specifically, the usage environment of the battery device 300 is usually 25 degrees Celsius to 45 degrees Celsius. Performing a cycle test on the single cell 301 after charging activation in an environment of 25 degrees Celsius to 45 degrees Celsius to obtain the cycle performance can improve the accuracy and reliability of the simulation, thereby improving the accuracy of the deterioration voltage.

[0102] The higher the ambient temperature, the faster the cycle speed of the single cell 301. In one embodiment, the cycle performance of the single cell 301 after charging activation is obtained by testing in an environment of 45 degrees Celsius, so as to accelerate the test speed of the cycle performance and obtain the cycle performance of the single cell 301 more quickly.

[0103] In some embodiments, please combine Figure 4 , step S05 includes:

[0104] Step S051, charging and activating the over-discharged single cell 301;

[0105] Step S053, after the single cell 301 is charged and activated, charge and discharge the battery device 300 and obtain the maximum charging voltage difference and the maximum discharging voltage difference of the battery device 300.

[0106] In the above embodiments, the maximum charging voltage difference and the maximum discharging voltage difference can be obtained, which is beneficial to confirm the state of the battery device 300 according to the maximum charging voltage difference and the maximum discharging voltage difference. Thus, on the one hand, it can avoid waste caused by scrapping the normally used battery device 300, and on the other hand, it can avoid the life and safety problems caused by the continued use of the scrapped battery device 300.

[0107] Specifically, in one embodiment, the discharged single cell 301 can be charged and activated to repair the over-discharged single cell 301. Charging and activating the discharged single cell 301 includes the steps carried out in the following order:

[0108] 1) Charge the single cell 301 to the lower limit voltage using the first constant charging parameter;

[0109] 2) Charge the single cell 301 to the first voltage using the second constant charging parameter, where the first voltage is greater than the lower limit voltage;

[0110] 3) Charge the single cell 301 to the second voltage using the third constant charging parameter, where the second voltage is greater than the first voltage;

[0111] Among them, the third constant charging parameter is greater than the second constant charging parameter, the second constant charging parameter is greater than the first constant charging parameter, and the third constant charging parameter is less than the normal charging parameter of the single cell 301.

[0112] Optionally, the first constant charging parameter is 0.01C to 0.05C, or 0.01P to 0.05P; the second constant charging parameter is 0.05C to 0.1C, or 0.05P to 0.1P; the third constant charging parameter is 0.1C to 0.2C, or 0.1P to 0.2P. The first voltage is the voltage corresponding to 10% to 30% of the full charge of the single cell 301, the second voltage is the full charge voltage of the single cell 301, and the lower limit voltage refers to the lowest allowable discharge voltage value set to avoid over-discharge under normal working conditions of the single cell 301. Among them, C is the rated capacity of the battery device 300, and P is the rated power of the battery device 300. Different single cells 301 have different lower limit voltages. In one example, the lower limit voltage of the lithium iron phosphate cell is 2.5V; the lower limit voltage of the ternary lithium cell is 4.2V.

[0113] In one embodiment, please refer to Figure 5 , the battery device 300 can be electrically connected to the test device 1000. The test device 1000 can include a control device 200 and a power supply. When the voltage of the single cell 301 is greater than the deterioration voltage, the control device 200 can control the power supply to charge the battery device 300 and obtain the maximum charging voltage difference. The control device 200 can control the battery device 300 to discharge and obtain the maximum discharging voltage difference.

[0114] In one embodiment, please refer to Figure 6 , the test device 1000 may include a battery device 300, that is, the battery device 300 includes a control device 200. The control device 200 can be electrically connected to the single cell 301. When the voltage of the single cell 301 is greater than the deterioration voltage, the control device 200 can obtain the maximum charging voltage difference and the maximum discharging voltage difference during the next charge and discharge of the battery device 300. Optionally, the control device 200 includes a battery management system.

[0115] In some embodiments, the single cell 301 is a lithium battery cell, and the deterioration voltage is greater than or equal to 1 volt.

[0116] In the above embodiment, the single cell 301 is a lithium battery cell, and the deterioration voltage is greater than or equal to 1 volt, which can ensure the safety and charge-discharge performance of the battery device 300 confirmed to be in a normal state according to the deterioration voltage to a certain extent.

[0117] Specifically, a lithium battery cell refers to a single cell 301 in which lithium ions are charge carriers and migrate between the positive and negative electrodes through an electrolyte to achieve electrical energy storage and release.

[0118] It should be noted that when the single cell 301 is a lithium battery cell, the lithium battery cell is overdischarged, and the performance of the overdischarged lithium battery cell is tested. The performance test results of the lithium battery cell with a discharge cut-off voltage greater than or equal to 0.5V are better, and the overdischarge rebound voltage corresponding to the performance of the lithium battery cell with a discharge cut-off voltage greater than or equal to 0.5V is greater than or equal to 1V. Thus, a deterioration voltage greater than or equal to 1V can enable the battery device 300 confirmed to be in a normal state according to the deterioration voltage to have better performance and lower safety risks during continued use.

[0119] Please refer to Figure 5 and Figure 6 , a control device 200 according to an embodiment of the present invention includes a processor 220 and a memory 210. When the computer program stored in the memory 210 is executed by the processor 220, the steps of the state confirmation method according to any of the above embodiments are implemented.

[0120] Please refer to Figure 5 and Figure 6 , a test device 1000 according to an embodiment of the present invention includes the control device 200 according to the above embodiment.

[0121] Specifically, in one embodiment, please refer to Figure 6, the test device 1000 may include a battery device 300, that is, the battery device 300 may include a control device 200. The control device 200 may be electrically connected to the single cell 301. The control device 200 may monitor the voltage of the single cell 301 in real time. When the voltage of the single cell 301 is less than or equal to the deterioration voltage, it is confirmed that the state of the battery device 300 is a scrapped state; when the voltage of the single cell 301 is greater than the deterioration voltage, the maximum charging voltage difference and the maximum discharging voltage difference during the next charging and discharging of the battery device 300 are detected. When both the maximum charging voltage difference and the maximum discharging voltage difference are within the corresponding set ranges, it is confirmed that the state of the battery device 300 is a normal state. When at least one of the maximum charging voltage difference and the maximum discharging voltage difference of the battery device 300 exceeds the corresponding set range, it is confirmed that the state of the battery device 300 is a scrapped state. Optionally, the control device 200 may be a battery management system or be communicatively connected to a battery management system.

[0122] In one embodiment, please refer to Figure 5 , the battery device 300 may be electrically connected to the test device 1000. The test device 1000 may include a power supply and a control device 200. The control device 200 may obtain the voltage of the single cell 301. When the voltage of the single cell 301 is less than or equal to the deterioration voltage, it is confirmed that the state of the battery device 300 is a scrapped state; when the voltage of the single cell 301 is greater than the deterioration voltage, the control device 200 may control the power supply to charge and activate the over-discharged single cell 301 to repair the single cell 301, and then control the power supply to charge the battery device 300 and control the battery device 300 to discharge and obtain the maximum charging voltage difference and the maximum discharging voltage difference of the battery device 300. When both the maximum charging voltage difference and the maximum discharging voltage difference are within the corresponding set ranges, it is confirmed that the state of the battery device 300 is a normal state. When at least one of the maximum charging voltage difference and the maximum discharging voltage difference of the battery device 300 exceeds the corresponding set range, it is confirmed that the state of the battery device 300 is a scrapped state.

[0123] An embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor 220, the steps of the state confirmation method in any of the above embodiments are implemented.

[0124] In some embodiments, when the computer program is executed by a processor 220, the implemented state confirmation method includes:

[0125] Step S01, obtaining the voltage of the over-discharged single cell 301;

[0126] Step S03, when the voltage of the single cell 301 is less than or equal to the deterioration voltage, confirming that the state of the battery device 300 is a scrapped state;

[0127] Step S05: When the voltage of the single cell 301 is greater than the deterioration voltage, if both the maximum charging voltage difference and the maximum discharging voltage difference of the battery device 300 are within the corresponding set ranges, confirm that the state of the battery device 300 is normal; if at least one of the maximum charging voltage difference and the maximum discharging voltage difference of the battery device 300 exceeds the corresponding set range, confirm that the state of the battery device 300 is scrapped.

[0128] In the description of this specification, the descriptions with reference to terms such as "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0129] Any process or method description shown in the flowchart or described in other ways herein can be understood to represent a module, segment, or part of code including one or more executable actions for implementing a specific logical function or process. The scope of the preferred embodiments of the present invention includes additional implementations, where the functions can be executed in a manner that is not shown or discussed, including in a substantially simultaneous manner according to the involved functions or in a reverse order, which should be understood by those skilled in the technical field of the embodiments of the present invention.

[0130] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, combinations, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for confirming the state of a battery device after overdischarge, characterized in that: The battery device includes a single battery cell, and the state confirmation method includes: Obtaining the voltage of the single battery cell after overdischarge; When the voltage of the single cell is less than or equal to the deterioration voltage, confirming that the battery device is in a scrapped state; When the voltage of the single cell is greater than the deterioration voltage, when the maximum charging voltage difference and the maximum discharging voltage difference of the battery device are both within the corresponding set ranges, it is confirmed that the state of the battery device is a normal state; when at least one of the maximum charging voltage difference and the maximum discharging voltage difference of the battery device exceeds the corresponding set range, it is confirmed that the state of the battery device is a scrapped state.

2. The status confirmation method according to claim 1, characterized in that: The state confirmation method comprises: Obtain different discharge cut-off voltages; Discharging the single cell before overdischarge until the voltage of the single cell reaches the discharge cut-off voltage, so that the single cell is in an overdischarge state; After the single cell after over-discharge is left to stand for a first set time, obtaining an over-discharge rebound voltage of the single cell; The deterioration voltage is determined according to a plurality of over-discharge rebound voltages corresponding to different discharge cut-off voltages and the performance of the single battery cell after over-discharge.

3. The state confirmation method according to claim 2, characterized in that: Discharging the single cell before over-discharge until the voltage of the single cell reaches the discharge cut-off voltage, so that the single cell is in an over-discharge state, comprises: The single cell before over-discharge is over-discharged by using a current of milliampere level until the voltage of the single cell reaches the discharge cut-off voltage, so that the single cell is in an over-discharge state.

4. The status confirmation method according to claim 2, characterized in that: The performance of the single cell after overdischarge includes at least one of the following: Whether copper is deposited inside the single cell; The residual capacity and the recovery capacity of the single cell after charging and activating the single cell after overdischarge; The cycle performance of the single cell after charging and activation.

5. The status confirmation method according to claim 4, characterized in that: The cycle performance of the single cell after charge activation is obtained by testing at an environment of 25 degrees Celsius to 45 degrees Celsius.

6. The status confirmation method according to claim 1, characterized in that: The state confirmation method comprises: Charging and activating the over-discharged single battery cell; After the single cell is charged and activated, the battery device is charged and discharged to obtain the maximum charging voltage difference and the maximum discharging voltage difference of the battery device.

7. The status confirmation method according to any one of claims 1 to 6, characterized in that: The single cell is a lithium cell, and the deterioration voltage is greater than or equal to 1 volt.

8. A control device, characterized in that: include: processor, and; A memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the status confirmation method according to any one of claims 1 to 7 are implemented.

9. A testing device, characterized in that: Comprising the control device as claimed in claim 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the status confirmation method according to any one of claims 1 to 7 are implemented.

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