A battery health detection system, method and energy storage device

Abstract

This invention relates to the field of battery health status detection technology, and discloses a battery health status detection system, method, and energy storage device. The system includes at least one set of single-cell battery health status detection units, each consisting of a capacitor, a discharge resistor, an inductor, a first switch, a second switch, a voltage detection unit, and a current detection unit, as well as a controller. The capacitor and inductor are connected in series to form a charging branch, and the discharge resistor and the second switch are connected in series to form a discharging branch. Both the charging and discharging branches are connected in parallel with the corresponding single-cell battery being tested. A first switch is provided between the charging branch and the corresponding single-cell battery. The first and second switches are controlled by the controller, and the voltage detection unit and the current detection unit are connected to the controller. This battery health detection system can perform online health status detection of batteries in energy storage devices with lower implementation costs, smaller installation size, and greater safety.

Description

Technical Field

[0001] This invention relates to the field of battery health status detection technology, specifically to a battery health status detection system, method, and energy storage device. Background Technology

[0002] Assessing the health status of batteries has always been a challenge in the battery industry, as it is typically only possible to determine this through actual discharge capacity. Most existing online battery health monitoring solutions involve connecting resistors in series across each cell, monitoring the discharge voltage and current curves of the battery against these resistors, and calculating the battery's internal resistance (AC or DC) using either the AC or DC internal resistance method. The battery's health is then assessed based on changes in these internal resistances. However, the AC internal resistance method only represents polarization resistance and cannot fully reflect the battery's condition. It cannot detect aging issues with lead-acid battery plates, and the test current is generally small, inconsistent with actual operating conditions, and cannot detect corrosion at internal solder joints. While the DC current method addresses these shortcomings, with larger battery capacities, the high DC current discharged through the resistor results in a higher load power on the resistor, leading to a larger resistor size and increased overall energy storage cost. Furthermore, the high discharge current poses a higher safety risk, making it unsuitable as an online battery health monitoring solution. Therefore, a new battery health status detection solution that is low-cost, highly safe, compact, and fast needs to be designed. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a battery health status detection system, method and energy storage device, which can quickly detect the health status of the battery, has low implementation cost, small space occupation and higher safety, and is suitable for online battery health status detection of large-capacity energy storage devices.

[0004] To solve the above problems, the technical solution adopted by the present invention is as follows: A battery health status detection system includes at least one set of single-cell battery health status detection units composed of a capacitor, a discharge resistor, an inductor, a first switch, a second switch, a voltage detection unit, and a current detection unit, as well as a controller. The capacitor and the inductor are connected in series to form a charging branch, and the discharge resistor and the second switch are connected in series to form a discharging branch. Both the charging branch and the discharging branch are connected in parallel with the corresponding single-cell battery being detected. The first switch is provided between the charging branch and the corresponding single-cell battery. The voltage detection unit is used to detect the discharge voltage of the corresponding single-cell battery, and the current detection unit is used to detect the discharge current when the corresponding single-cell battery discharges to the corresponding capacitor. The first switch and the second switch are controlled by the controller. The voltage detection unit and the current detection unit are connected to the controller. The controller is used to control the single-cell battery to discharge to the corresponding capacitor when a battery health status detection request is received. The controller samples and records the change curves of discharge voltage and discharge current during the charging process through the voltage detection unit and the current detection unit until the discharge current becomes 0. The controller analyzes the health status of the battery based on the sampled change curves of discharge voltage and discharge current.

[0005] The aforementioned battery health status detection system includes the following controller: a sampling module, used to sample the voltage value of each voltage detection unit and the current value of each current detection unit according to a preset sampling period; a detection control module, used to control each first switch to close and control each second switch to open when a battery health status detection request is received, and to control the corresponding first switch to open and control the corresponding second switch to close when the current detection unit detects that the discharge current becomes 0; a data processing module, used to calculate the DC internal resistance of each battery, the DC internal resistance sample deviation, the voltage minimum point sample deviation, the time to reach the voltage minimum point sample deviation, and the coefficient of variation of the DC internal resistance of the entire battery pack based on the changes in discharge voltage and discharge current during the discharge process of each battery to the corresponding capacitor; and a health status judgment module, used to judge the health status of each battery and the entire battery pack based on the parameters calculated by the data processing module and a preset threshold.

[0006] The aforementioned battery health status detection system includes a data processing module comprising: a lookup module, used to analyze the discharge voltage variation curve and discharge current variation curve of each battery cell to determine the maximum current I of each battery cell. kmax Current I kmax The corresponding voltage V kimax The current I at half the maximum current khmax Current I khmax Half of the corresponding voltage Vkihmax Voltage V at the lowest voltage point kmin and the corresponding time T for reaching the lowest voltage point. kn The parameter calculation module is used to calculate the DC internal resistance of each battery, the DC internal resistance sample deviation, the voltage minimum point sample deviation, the voltage minimum point time sample deviation, and the coefficient of variation of the DC internal resistance of the entire battery pack based on the current and voltage parameters output by the search module. The health status judgment module is also used to compare the DC internal resistance, DC internal resistance sample deviation, voltage minimum point sample deviation, voltage minimum point time sample deviation, and the coefficient of variation of the DC internal resistance of the entire battery group output by the data processing module with their respective thresholds, and to give battery replacement suggestions based on the comparison results.

[0007] In the aforementioned battery health status detection system, the capacitor is an electrolytic capacitor. The positive terminal of the capacitor is connected to the positive terminal of the corresponding single battery cell through the inductor and the first switch, and the negative terminal of the capacitor is connected to the negative terminal of the corresponding single battery cell through the shunt of the current detection unit.

[0008] An energy storage device includes the aforementioned battery health status monitoring system.

[0009] A method for detecting the health status of a battery in the aforementioned battery health status detection system, characterized in that it includes: Has a battery health status check request been received? If so, disconnect the second switch. The control voltage detection unit and the current detection unit start sampling the discharge voltage and discharge current of each battery according to the preset sampling period; Wait for the preset waiting time, then close the first switch; If the discharge current becomes 0, then close the corresponding second switch and open the first switch; The health status of each battery cell and the entire battery pack is assessed based on the discharge voltage and discharge current variation curves of each cell.

[0010] The above-mentioned battery health status detection method includes the following steps: assessing the health status of each battery cell and the entire battery pack based on the discharge voltage and discharge current variation curves of each cell. Analyze the discharge voltage and discharge current curves of each battery cell to determine the maximum current I of each cell. kmax Current I kmax The corresponding voltage V kimax The current I at half the maximum current khmax Current I khmax Half of the corresponding voltage V kihmax Voltage V at the lowest voltage pointkmin and the corresponding time T for reaching the lowest voltage point. kn ; Calculate the DC internal resistance R of each battery cell. k直流内阻 =(V kimax –V kihmax ) / (I kmax –I khmax ); The sample deviation of the DC internal resistance of each cell is calculated based on the DC internal resistance of each cell. Calculate the coefficient of variation of the DC internal resistance of the entire battery pack based on the DC internal resistance of each battery cell. Based on the voltage V of each battery kmin Calculate the sample deviation of the lowest voltage point for each battery cell; Based on the time T when each battery reaches its lowest voltage point kn Calculate the sample deviation of the time when the voltage of each battery is lowest; Calculate the coefficient of variation of the DC internal resistance of the entire battery pack based on the DC internal resistance of the entire battery pack. The health status of the entire battery pack is determined by the coefficient of variation of the DC internal resistance of the entire battery pack, and the health status of each battery is determined by the DC internal resistance of each battery, the sample deviation of the DC internal resistance, the sample deviation of the lowest voltage point, the sample deviation of the lowest voltage time, and the sample deviation of the lowest voltage time.

[0011] In the above-mentioned battery health status detection method, in the step of judging the health status of the entire battery pack based on the coefficient of variation of the DC internal resistance of the entire battery pack, and judging the health status of each individual battery based on the DC internal resistance, sample deviation of DC internal resistance, sample deviation of the lowest voltage point, sample deviation of the lowest voltage time, and sample deviation of the lowest voltage time: if the value of the coefficient of variation of the entire battery pack exceeds a preset coefficient of variation threshold, the health status of the entire battery pack is judged to be poor, and an alarm for replacing the entire pack is issued; if the DC internal resistance of a certain battery exceeds a preset multiple of the DC resistance of the new battery, the sample deviation of the DC resistance exceeds a preset resistance deviation threshold, the sample deviation of the lowest voltage point exceeds a preset voltage deviation threshold, or the sample deviation of the lowest voltage time exceeds a preset time deviation threshold, the health status of that battery is judged to be poor, and an alarm for replacing that battery is issued.

[0012] Compared to existing technologies, the advantages of this invention are as follows: 1. By using a capacitor as the discharge load for battery health status detection, the current automatically drops to 0 after the capacitor is fully charged, preventing the battery from continuously discharging and depleting its stored energy. Furthermore, the discharge process is short-lived and the discharge current gradually decreases, avoiding the safety hazards associated with continuous high-current discharge, thus enhancing safety. 2. The detection unit for a single battery only requires one capacitor, one inductor, and several switches. There is no need to configure high-resistance resistors for the high-current discharge during the detection of large-capacity batteries, reducing system size and cost. 3. In addition to using DC internal resistance to determine the health status of a single battery, statistical data analysis is combined to analyze the deviation between the health status of a single battery and the overall battery pack. Through a series of statistical analyses, a more accurate assessment of battery health status is achieved.

[0013] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the battery health status detection system according to the first embodiment of the present invention.

[0015] Figure 2 This is a schematic diagram of a battery health status detection system according to a second embodiment of the present invention.

[0016] Figure 3 This is a flowchart of the detection action of the detection system according to an embodiment of the present invention. Detailed Implementation

[0017] The embodiments of the present invention are described in detail below, with reference to... Figure 1This invention provides a battery health status detection system, including at least one set of single-cell battery health status detection units composed of a capacitor, a discharge resistor, an inductor, a first switch S1, a second switch S2, a voltage detection unit, and a current detection unit, as well as a controller. The capacitor and inductor are connected in series to form a charging branch, and the discharge resistor and the second switch S2 are connected in series to form a discharging branch. Both the charging and discharging branches are connected in parallel with the corresponding single-cell battery being detected. A first switch S1 is provided between the charging branch and the corresponding single-cell battery. The current detection unit is used to detect the discharge current of the single-cell battery when discharging to the corresponding capacitor, and the voltage detection unit is used to detect the discharge voltage of the single-cell battery. The first switch S1, the second switch S2, the current detection unit, and the voltage detection unit are all controlled by the controller. The controller is used to close the first switch S1 and open the second switch S2 when performing battery health status detection, so that a single battery cell is connected to the corresponding capacitor and the capacitor is charged. The controller collects and records the changes in discharge voltage and discharge current during the battery charging process through the current detection unit and the voltage detection unit, and analyzes the health status of each battery cell and the entire battery pack based on the discharge voltage curve and the discharge current curve.

[0018] This testing system uses a capacitor as the discharge load during battery testing. Because the capacitor charges quickly, it rapidly assesses the battery's health. Once fully charged, the charging current is automatically cut off, preventing accidental depletion of the battery due to operational errors. This ensures the energy storage device remains powered even during health checks. During testing, the discharge current gradually decreases as the capacitor charges, avoiding the safety hazards of excessive discharge current in large-capacity batteries. This makes it more suitable for online health status monitoring of large-capacity energy storage devices. Furthermore, by using a capacitor instead of a resistor, the system eliminates the need for bulky and expensive high-resistance resistors for the high-current discharge of large-capacity batteries, reducing the overall system's implementation cost and size.

[0019] Understandably, referring to Figure 2 In some embodiments, if the energy storage device includes multiple batteries, the detection system also includes multiple sets of single-cell battery health status detection units, which are connected in parallel to the two ends of the multiple batteries.

[0020] It is understood that the controller may include a processor and a memory. The processor can control the first switch S1 and the second switch S2 by calling and executing computer programs in the memory to instantiate the sampling module, the detection control module, the data processing module, and the health status judgment module, and to collect and analyze the battery's discharge voltage and discharge current to detect the health status of each battery cell and the entire battery pack. Specifically, the sampling module is used to sample the voltage value of each voltage detection unit and the current value of each current detection unit according to a preset sampling period, such as 10ms, to obtain the change curves of discharge voltage and discharge current during the battery's charging process with the capacitor. The detection control module, upon receiving a battery health status detection request, controls each first switch S1 to close and controls each second switch S2 to open, so that each individual battery cell is connected to its corresponding capacitor for charging; and when the current detection unit detects that the discharge current becomes 0, it controls the corresponding first switch S1 to open and controls the corresponding second switch S2 to close, so that the capacitor is connected to the discharge resistor to release the electrical energy in the capacitor for the next detection. The data processing module calculates the DC internal resistance, DC internal resistance sample deviation, minimum voltage point sample deviation, minimum voltage point time sample deviation, and the coefficient of variation of the DC internal resistance of the entire battery pack based on the changes in discharge voltage and discharge current of each battery during the discharge process of its corresponding capacitor. This allows for statistical analysis of the deviation of each battery from the average condition of the entire battery pack, combining the DC internal resistance of each individual battery to analyze the health status of each battery and improve the accuracy of health status assessment. The health status assessment module determines the health status of each battery and the entire battery pack based on the parameters calculated by the data processing module and preset thresholds.

[0021] In this embodiment, the data processing module specifically includes a lookup module and a parameter calculation module. The lookup module analyzes the discharge voltage and discharge current variation curves of each battery cell to determine the maximum current I of each cell. kmax Current I kmax The corresponding voltage V kimax The current I at half the maximum current khmax Current I khmax Half of the corresponding voltage V kihmax Voltage V at the lowest voltage point kmin and the corresponding time T for reaching the lowest voltage point. kn The parameter calculation module is used to calculate the current I output by the lookup module. kmax I khmax and voltage V kimax and V kihmax Calculate the DC internal resistance of each battery cell, and based on the DC internal resistance, calculate the sample deviation of the DC internal resistance of each battery cell. Then, based on the voltage V... kmin and the time T to reach the lowest voltage pointkn The system calculates the voltage minimum point sample deviation and voltage minimum point time sample deviation for each battery cell, and calculates the coefficient of variation of the DC internal resistance of the entire battery pack based on the calculated DC internal resistance of each battery cell. The health status assessment module also compares the DC internal resistance of each battery cell, the DC internal resistance sample deviation, the voltage minimum point sample deviation, the voltage minimum point time sample deviation, and the coefficient of variation of the DC internal resistance of the entire battery pack output by the data processing module with their respective thresholds, and provides battery replacement recommendations based on the comparison results.

[0022] It is understandable that the voltage detection unit and the current detection unit can respectively use a voltmeter and an ammeter, or they can be composed of a voltage sensor or a current sensor combined with an AD conversion module. (Refer to...) Figure 1 In this embodiment, an electrolytic capacitor is used, which has a larger capacity for the same volume compared to a conventional capacitor, and can meet the capacitance requirements of the detection process in a smaller volume. The positive terminal of the capacitor is connected to the positive terminal of the corresponding single battery cell through an inductor and the first switch S1, and the negative terminal is connected to the negative terminal of the corresponding single battery cell through a shunt in the current detection unit.

[0023] Based on the same inventive concept, embodiments of the present invention also provide an energy storage device, including the aforementioned battery health status detection system. The energy storage device can be a UPS power supply or an energy storage cabinet, etc.

[0024] Based on the same inventive concept, referring to Figure 3 The present invention also provides a method for detecting the health status of a battery, which can be implemented by the above-described method for detecting the health status of a battery and the energy storage device, including: Has a battery health status check request been received? If so, disconnect the second switch. The control voltage detection unit and the current detection unit start sampling the discharge voltage and discharge current of each battery according to the preset sampling period; it can be understood that the discharge voltage and current of each battery need to be sampled synchronously. Wait for a preset waiting time, such as 10ms, until the voltage detection unit detects the initial voltage V when the battery current is 0. k0A Then close the first switch; If the discharge current becomes 0, then close the corresponding second switch and open the first switch; The health status of each battery cell and the entire battery pack is assessed based on the discharge voltage and discharge current variation curves of each cell.

[0025] In practice, the individual cells in an energy storage device's battery pack need to maintain a certain degree of consistency to achieve optimal energy storage and discharge performance. Therefore, the degree of deviation of an individual cell's indicators can be used to determine the degree of deviation between the health of an individual cell and the overall battery pack. Furthermore, the health of the entire battery pack can be evaluated based on the dispersion of its DC internal resistance. Poor battery discharge capacity also leads to an increased terminal voltage drop during discharge, a faster time to reach the lowest voltage point, and an increased DC internal resistance. These indicators can also be used to intuitively determine the health of an individual cell. Specifically, in this embodiment, the DC internal resistance, the sample deviation of the lowest voltage point, and the sample deviation of the lowest voltage time for each cell are calculated based on the discharge voltage and discharge current change curves of each cell. The sample deviation and coefficient of variation of the DC internal resistance of each cell are also calculated based on the DC internal resistance. These further parameters are used to determine the health status of individual cells and the entire battery pack.

[0026] Among them, the DC internal resistance R of the k-th battery k直流内阻 It can be obtained by calculation using the following formula: R k直流内阻 =(V kimax –V kihmax ) / (I kmax –I khmax (1); The sample deviation S of the DC internal resistance of the k-th battery k直流电阻 It can be obtained by calculation using the following formula: (2); in This represents the average DC internal resistance of the entire battery pack.

[0027] The coefficient of variation (CV) of the DC internal resistance of the entire battery pack can be calculated using the following formula: CV= (3); in This represents the standard deviation of the DC internal resistance of the entire battery pack.

[0028] The sample deviation S at the lowest point of the k-th battery kVmin It can be obtained by calculation using the following formula: (4); in This is the average voltage value of the lowest voltage point in the entire battery pack.

[0029] The sample deviation S of the time when the k-th battery reaches its lowest voltage kT It can be obtained by calculation using the following formula: (5); in This is the average time it takes for the entire battery pack to reach its lowest voltage point.

[0030] In this embodiment, when the coefficient of variation (CV) exceeds a preset threshold, it indicates that the overall health of the battery pack is poor, and the controller issues a warning to the maintenance personnel to replace the entire battery pack. Similarly, when the DC internal resistance of a single battery exceeds twice that of a new battery, the sample deviation of the lowest voltage point of that battery exceeds a preset voltage deviation threshold, or the sample deviation of the lowest voltage time of that battery exceeds a preset time deviation threshold, the health of that battery is determined to be poor, and the controller issues a warning to the maintenance personnel to replace that battery. In this embodiment, the voltage deviation threshold and the time deviation threshold can be set to 0.3.

[0031] It should be noted that in the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is mentioned, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0032] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations 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, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0033] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0034] These computer program instructions can also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0035] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0036] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A battery health status detection system, characterized in that, The system includes at least one single-cell battery health status detection unit consisting of a capacitor, a discharge resistor, an inductor, a first switch, a second switch, a voltage detection unit, and a current detection unit, as well as a controller. The capacitor and the inductor are connected in series to form a charging branch, and the discharge resistor and the second switch are connected in series to form a discharging branch. Both the charging branch and the discharging branch are connected in parallel with the corresponding single-cell battery being tested. The first switch is provided between the charging branch and the corresponding single-cell battery. The voltage detection unit is used to detect the discharge voltage of the corresponding single-cell battery, and the current detection unit is used to detect the discharge current when the corresponding single-cell battery discharges to the corresponding capacitor. The first switch and the second switch are controlled by the controller, and the voltage detection unit and the current detection unit are connected to the controller. The controller is used to control the single-cell battery to discharge to the corresponding capacitor when it receives a battery health status detection request. The controller samples and records the change curves of discharge voltage and discharge current during the charging process through the voltage detection unit and the current detection unit until the discharge current becomes 0. The controller analyzes the health status of the battery based on the sampled change curves of discharge voltage and discharge current.

2. The battery health status detection system according to claim 1, characterized in that, The controller includes: The sampling module is used to sample the voltage value of each voltage detection unit and the current value of each current detection unit according to a preset sampling period; The detection control module is used to control each of the first switches to close and control each of the second switches to open when a battery health status detection request is received, and to control the corresponding first switch to open and control the corresponding second switch to close when the current detection unit detects that the discharge current becomes 0. The data processing module is used to calculate the DC internal resistance of each battery, the DC internal resistance sample deviation, the sample deviation of the lowest voltage point, the sample deviation of the time to reach the lowest voltage point, and the coefficient of variation of the DC internal resistance of the entire battery pack based on the changes in discharge voltage and discharge current of each battery during the discharge process of the corresponding capacitor. The health status judgment module is used to judge the health status of each battery and the entire battery pack based on the parameters calculated by the data processing module and the preset threshold.

3. The battery health status detection system according to claim 2, characterized in that, The data processing module includes: The search module is used to analyze the discharge voltage and discharge current variation curves of each battery cell to determine the maximum current I of each battery cell. kmax Current I kmax The corresponding voltage V kimax The current I at half the maximum current khmax Current I khmax Half of the corresponding voltage V kihmax Voltage V at the lowest voltage point kmin and the corresponding time T for reaching the lowest voltage point. kn ; The parameter calculation module is used to calculate the DC internal resistance of each battery, the DC internal resistance sample deviation, the voltage minimum point sample deviation, the voltage minimum point time sample deviation, and the coefficient of variation of the DC internal resistance of the entire battery pack based on the current and voltage parameters output by the search module. The health status judgment module is also used to compare the DC internal resistance, DC internal resistance sample deviation, voltage minimum point sample deviation, voltage minimum point time sample deviation, and the coefficient of variation of the DC internal resistance of the entire battery group output by the data processing module with their respective thresholds, and to give battery replacement suggestions based on the comparison results.

4. The battery health status detection system according to claim 1, characterized in that, The capacitor is an electrolytic capacitor. The positive terminal of the capacitor is connected to the positive terminal of the corresponding single battery cell through the inductor and the first switch, and the negative terminal of the capacitor is connected to the negative terminal of the corresponding single battery cell through the shunt of the current detection unit.

5. An energy storage device, characterized in that, Includes the battery health status detection system according to any one of claims 1 to 4.

6. A method for detecting battery health status using a battery health status detection system according to any one of claims 1 to 4, characterized in that, include: Has a battery health status check request been received? If so, disconnect the second switch. The control voltage detection unit and the current detection unit start sampling the discharge voltage and discharge current of each battery according to the preset sampling period; Wait for the preset waiting time, then close the first switch; If the discharge current becomes 0, then close the corresponding second switch and open the first switch; The health status of each battery cell and the entire battery pack is assessed based on the discharge voltage and discharge current variation curves of each cell.

7. The battery health status detection method according to claim 6, characterized in that, The steps for assessing the health status of each battery cell and the entire battery pack based on the discharge voltage and discharge current variation curves of each cell include: Analyze the discharge voltage and discharge current curves of each battery cell to determine the maximum current I of each cell. kmax Current I kmax The corresponding voltage V kimax The current I at half the maximum current khmax Current I khmax Half of the corresponding voltage V kihmax Voltage V at the lowest voltage point kmin and the corresponding time T for reaching the lowest voltage point. kn ; Calculate the DC internal resistance R of each battery cell. k直流内阻 =(V kimax –V kihmax ) / (I kmax –I khmax ); The sample deviation of the DC internal resistance of each cell is calculated based on the DC internal resistance of each cell. Calculate the coefficient of variation of the DC internal resistance of the entire battery pack based on the DC internal resistance of each battery cell. Based on the voltage V of each battery kmin Calculate the sample deviation of the lowest voltage point for each battery cell; Based on the time T when each battery reaches its lowest voltage point kn Calculate the sample deviation of the time when the voltage of each battery is lowest; Calculate the coefficient of variation of the DC internal resistance of the entire battery pack based on the DC internal resistance of the entire battery pack. The health status of the entire battery pack is determined by the coefficient of variation of the DC internal resistance of the entire battery pack, and the health status of each battery is determined by the DC internal resistance of each battery, the sample deviation of the DC internal resistance, the sample deviation of the lowest voltage point, the sample deviation of the lowest voltage time, and the sample deviation of the lowest voltage time.

8. The battery health status detection method according to claim 7, characterized in that, In the step of determining the health status of the entire battery pack based on the coefficient of variation of the DC internal resistance of the entire battery pack, and determining the health status of each individual battery based on the DC internal resistance, sample deviation of DC internal resistance, sample deviation of the lowest voltage point, sample deviation of the lowest voltage time, and sample deviation of the lowest voltage time: if the value of the coefficient of variation of the entire battery pack exceeds a preset coefficient of variation threshold, the health status of the entire battery pack is determined to be poor, and an alarm for replacing the entire pack is issued; if the DC internal resistance of a certain battery exceeds a preset multiple of the DC resistance of the new battery, the sample deviation of the DC resistance exceeds a preset resistance deviation threshold, the sample deviation of the lowest voltage point exceeds a preset voltage deviation threshold, or the sample deviation of the lowest voltage time exceeds a preset time deviation threshold, the health status of that battery is determined to be poor, and an alarm for replacing that battery is issued.

Images