Power battery diagnosis circuit and control method therefor, and power battery

Abstract

A power battery diagnosis circuit and a control method therefor, and a power battery. The power battery diagnosis circuit comprises: an equalization module, an equalization diagnosis module, a sampling diagnosis module and a control module, wherein the equalization module and the equalization diagnosis module are both connected in parallel to an equalization switch in an equalization circuit, and the control module is separately connected to the equalization module, the equalization diagnosis module and the sampling diagnosis module. The control module is used for controlling the equalization switch to be in an on state during line diagnosis, such that the equalization module discharges, controlling the equalization switch to be in an off state after the equalization switch remains in the on state for a first preset time, and controlling the equalization diagnosis module and the sampling diagnosis module, so as to perform line diagnosis on a sampling branch and the equalization circuit.

Description

Power battery diagnostic circuit and control method thereof, and power battery

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application number 2024103112479, filed on March 18, 2024, entitled “Diagnostic circuit for power battery, control method thereof, and power battery”, the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the technical field of power batteries, and in particular to a diagnostic circuit of a power battery, a control method of the diagnostic circuit of a power battery, and a power battery. Background Art

[0004] With the current trend toward 800V and even higher power voltage platforms in electric vehicles, and the increased power of inductive load-driven motors, the voltage surge interference on the power battery busbar has also increased significantly. These surge interference on the busbar is distributed through the battery sampling harness to the battery sampling board of the BMS (Battery Management System), causing unstable sampling on the sampling board. In addition, excessive surges will preferentially pass through the low-impedance balancing circuit through the sampling line, which can easily cause overvoltage damage to the MOS (Metal Oxide Semiconductor) tubes built into the balancing circuit of the sampling board, further causing over-discharge of the battery cells.

[0005] In order to prevent the surge impact on the high-voltage platform power battery busbar from being transmitted along the cell sampling line to the cell sampling board of the BMS, further affecting the sampling error, balancing function, and sampling line break diagnosis, there are currently few effective response plans for the application of high-voltage platforms, and most solutions are implemented from the source and path. In related technologies, considering the diversity of power battery loads and working scenarios, the cost of eliminating surges at the source based on the power battery load end and charging pile is high, and it is difficult to completely eliminate it in general engineering design; from the path, a TVS (Transient Voltage Suppressor) protection tube is added to each sampling (balancing) channel to prevent surges from damaging the low-impedance balancing circuit, and the sampling filter time is increased in the software to obtain a more accurate cell sampling voltage value. However, these operations, on the one hand, lead to a sharp increase in the cost of each unit, and on the other hand, sacrifice the performance of the sampling function, extend the sampling cycle, and poor data real-time performance.

[0006] Public content

[0007] The present disclosure aims to at least partially address one of the technical issues in the related art. To this end, the first objective of the present disclosure is to provide a diagnostic circuit for a power battery that, when performing circuit diagnosis, first discharges the equalization module via an equalization switch, then performs circuit diagnosis on the sampling branch and equalization loop via the equalization diagnostic module and the sampling diagnostic module. This circuit achieves stable sampling at low cost, shortens the sampling cycle, and improves the protection capability of the battery cell sampling board and diagnostic reliability.

[0008] A second objective of the present disclosure is to provide a control method for a diagnostic circuit of a power battery.

[0009] The third objective of the present disclosure is to provide a power battery.

[0010] To achieve the above-mentioned objectives, an embodiment of the first aspect of the present disclosure proposes a diagnostic circuit for a power battery, comprising: a balancing module, a balancing diagnostic module, a sampling diagnostic module and a control module, wherein the balancing module and the balancing diagnostic module are both connected in parallel with the balancing switch in the balancing circuit, and the control module is respectively connected to the balancing switch, the balancing diagnostic module and the sampling diagnostic module, wherein the control module is configured to control the balancing switch to be in the on state when performing circuit diagnosis so as to discharge the balancing module, and to control the balancing switch to be in the off state after the balancing switch is continuously on for a first preset time, and to control the balancing diagnostic module and the sampling diagnostic module to perform circuit diagnosis on the sampling branch and the balancing circuit.

[0011] According to the diagnostic circuit of the power battery of the embodiment of the present disclosure, when performing circuit diagnosis, the control module controls the balancing switch to be in the conductive state to discharge the balancing module. After the balancing switch is continuously conductive for a first preset time, the control module controls the balancing switch to be in the disconnected state. The balancing diagnostic module and the sampling diagnostic module are then controlled to perform circuit diagnosis on the sampling branch and the balancing loop. As a result, when performing circuit diagnosis, the circuit can first discharge the balancing module through the balancing switch, and then perform circuit diagnosis on the sampling branch and the balancing loop through the balancing diagnostic module and the sampling diagnostic module. This ensures stable sampling and low cost. It can also shorten the sampling cycle, improve the protection capability of the battery cell sampling board, and enhance the diagnostic reliability.

[0012] In addition, the diagnostic circuit of the power battery according to the above embodiment of the present disclosure may also have the following additional technical features:

[0013] According to one embodiment of the present disclosure, the sampling diagnosis module includes: a first switch and a first resistor, wherein one end of the first switch is connected to the first sampling point of the sampling branch, and the other end of the first switch is connected to the second sampling point of the sampling branch through the first resistor.

[0014] According to one embodiment of the present disclosure, the balancing diagnostic module includes: a second switch and a second resistor connected in series, wherein one end of the second switch is connected to one end of the balancing switch, and the other end of the second switch is connected to the other end of the balancing switch through a second resistor.

[0015] According to one embodiment of the present disclosure, the control module is further configured to control the first switch to be in a closed state, control the second switch to be in an open state, and perform circuit diagnosis according to the voltage value of the first resistor.

[0016] According to one embodiment of the present disclosure, the control module is further configured to control the first switch to be in an open state and control the second switch to be in a closed state, so as to perform circuit diagnosis according to the voltage value of the second resistor.

[0017] According to an embodiment of the present disclosure, the balancing module includes: a balancing capacitor, wherein the balancing capacitor is connected in parallel with the balancing switch.

[0018] According to an embodiment of the present disclosure, the capacitance of the balancing capacitor is determined by the surge voltage and the heat generated by the surge voltage applied to the balancing circuit.

[0019] According to an embodiment of the present disclosure, the first preset time is determined by the internal resistance of the balancing switch and the capacitance of the balancing capacitor.

[0020] According to an embodiment of the present disclosure, the balancing switch is a MOS tube.

[0021] To achieve the above-mentioned objectives, an embodiment of the second aspect of the present disclosure proposes a control method for the diagnostic circuit of the above-mentioned power battery, the method comprising: when performing circuit diagnosis on the power battery, controlling the balancing switch in the balancing circuit to be in the on state so that the balancing module discharges, and after the balancing switch is continuously on for a first preset time, controlling the balancing switch to be in the off state; controlling the balancing diagnostic module and the sampling diagnostic module to perform circuit diagnosis on the sampling branch and the balancing circuit.

[0022] According to the control method for the diagnostic circuit of a power battery according to an embodiment of the present disclosure, when performing circuit diagnosis on a sampling branch power battery, the balancing switch in the balancing circuit is first controlled to be in the on state to enable the balancing module to discharge. After the sampling branch balancing switch is continuously on for a first preset time, the sampling branch balancing switch is controlled to be in the off state. Then, the balancing diagnostic module and the sampling diagnostic module are controlled to perform circuit diagnosis on the sampling branch and the sampling branch balancing circuit. As a result, when performing circuit diagnosis, the method can first discharge the balancing module through the balancing switch, and then perform circuit diagnosis on the sampling branch and the balancing circuit through the balancing diagnostic module and the sampling diagnostic module. The sampling is stable and low-cost, and the sampling cycle can be shortened, thereby improving the protection capability and diagnostic reliability of the battery cell sampling board.

[0023] To achieve the above objectives, a third embodiment of the present disclosure provides a power battery, comprising: at least one single cell, and the above-mentioned power battery diagnostic circuit arranged corresponding to each single cell.

[0024] According to the power battery of the embodiment of the present disclosure, through the above-mentioned diagnostic circuit of the power battery, when performing line diagnosis, the balancing module can be discharged through the balancing switch first, and then the sampling branch and the balancing loop can be diagnosed through the balancing diagnostic module and the sampling diagnostic module. The sampling is stable and low-cost, and the sampling cycle can be shortened, thereby improving the protection capability and diagnostic reliability of the battery cell sampling board.

[0025] Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a block diagram of a diagnostic circuit for a power battery according to an embodiment of the present disclosure;

[0027] FIG2 is a topological diagram of a diagnostic circuit for a power battery according to one embodiment of the present disclosure;

[0028] FIG3 is an equivalent circuit diagram of a balancing switch that is not conducting during line diagnosis according to an embodiment of the present disclosure;

[0029] FIG4 is a flow chart of a method for controlling a diagnostic circuit of a power battery according to an embodiment of the present disclosure;

[0030] FIG5 is a block diagram of a power battery according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0031] The following describes in detail embodiments of the present disclosure, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, and should not be construed as limiting the present disclosure.

[0032] The following describes a power battery diagnostic circuit, a power battery diagnostic circuit control method, and a power battery according to embodiments of the present disclosure with reference to the accompanying drawings.

[0033] FIG1 is a block diagram of a diagnostic circuit for a power battery according to an embodiment of the present disclosure.

[0034] As shown in FIG1 , a diagnostic circuit 100 for a power battery according to an embodiment of the present disclosure includes: a balancing module 110, a balancing diagnostic module 120, a sampling diagnostic module 130, and a control module 140. The balancing module 110 and the balancing diagnostic module 120 are both connected in parallel with a balancing switch 150 in a balancing circuit. The control module 140 is connected to the balancing switch 150, the balancing diagnostic module 120, and the sampling diagnostic module 130, respectively. The control module 140 is configured to control the balancing switch 150 to be in an on state during circuit diagnosis to discharge the balancing module 110, and to control the balancing switch 150 to be in an off state after the balancing switch 150 has been on for a first preset time, and to control the balancing diagnostic module 120 and the sampling diagnostic module 130 to perform circuit diagnosis on the sampling branch and the balancing circuit.

[0035] Specifically, as shown in FIG1 , the power battery diagnostic circuit 100 is connected to the ends of the nth single cell in the power battery via sampling lines A and B. The sampling diagnostic module 130 can sample the voltage across the single cell via sampling lines A and B and transmit the sampled value to the battery management system (BMS) of the single cell. The BMS determines whether balancing is required based on the voltage value of each single cell. When a surge on the power battery bus is coupled to sampling line A and then transmitted to the sampling diagnostic module 130, it can cause the single cell to falsely report an overvoltage or undervoltage fault. In addition, a large surge causes a large voltage difference between sampling lines A and B. Since the impedance of the balancing circuit is relatively lower than the impedance of the sampling branch (the impedance of the balancing circuit is tens of ohms, while the impedance of the sampling branch is several thousand ohms), the surge preferentially flows through the balancing circuit, increasing the risk of breakdown of the balancing switch 150. The balancing module 110 can absorb the higher surge voltage, thereby preventing sampling instability in the sampling diagnostic module 130 and breakdown of the balancing switch 150.

[0036] When performing line diagnosis to determine whether a line break fault exists, the control module 140 controls the balancing switch 150 to conduct, allowing the power stored in the balancing module 110 to be discharged through the balancing switch 150. After the balancing switch 150 remains on for a first preset time, the control module 140 controls the balancing switch 150 to be turned off. The control module 140 then controls the balancing diagnostic module 120 to perform line diagnosis on the balancing circuit to determine whether a line break fault exists in the balancing circuit, and controls the sampling diagnostic module 130 to perform line diagnosis on the sampling branch to determine whether a line break fault exists in the sampling branch.

[0037] Therefore, the diagnostic circuit of the power battery of the embodiment of the present disclosure can, when performing line diagnosis, first discharge the balancing module through the balancing switch, and then perform line diagnosis on the sampling branch and the balancing loop through the balancing diagnostic module and the sampling diagnostic module. The sampling is stable and low-cost, and the sampling cycle can be shortened, thereby improving the protection capability and diagnostic reliability of the battery cell sampling board.

[0038] According to one embodiment of the present disclosure, as shown in FIG2 , the sampling diagnosis module 130 includes: a first switch K1 and a first resistor R1 , wherein one end of the first switch K1 is connected to a first sampling point of a sampling branch, and the other end of the first switch K1 is connected to a second sampling point of the sampling branch via the first resistor R1 .

[0039] According to one embodiment of the present disclosure, as shown in FIG2 , the balancing diagnostic module 120 includes: a second switch K2 and a second resistor R2 connected in series, wherein one end of the second switch K2 is connected to one end of the balancing switch 150 , and the other end of the second switch K2 is connected to the other end of the balancing switch 150 via the second resistor R2 .

[0040] According to an embodiment of the present disclosure, the control module 140 is further configured to control the first switch K1 to be in a closed state, control the second switch K2 to be in an open state, and perform circuit diagnosis according to the voltage value of the first resistor R1.

[0041] According to an embodiment of the present disclosure, the control module 140 is further configured to control the first switch K1 to be in an open state and the second switch K2 to be in a closed state, so as to perform circuit diagnosis according to the voltage value of the second resistor R2.

[0042] Specifically, when performing line diagnosis to determine whether there is a line break fault in the line, the control module 140 controls the balancing switch 150 to be turned on, so that the power stored in the balancing module 110 is discharged through the balancing switch 150. After the balancing switch 150 is continuously turned on for a first preset time, the control module 140 controls the balancing switch 150 to be turned off. When the sampling diagnosis module 130 performs line diagnosis on the sampling branch to determine whether there is a line break fault in the sampling branch, the control module 140 controls the first switch K1 to be closed and the second switch K2 to be opened. The control module 140 obtains the voltage value of the first resistor R1 and compares the voltage value of the first resistor R1 with the undervoltage threshold value when the sampling line breaks. When the voltage value of the first resistor R1 is less than the undervoltage threshold value when the sampling line breaks, it can be determined that there is no line break fault in the sampling branch. When the voltage value of the first resistor R1 is greater than or equal to the undervoltage threshold value when the sampling line breaks, it can be determined that there is a line break fault in the sampling branch.

[0043] Furthermore, when the balancing diagnostic module 120 performs line diagnosis on the balancing circuit and determines whether a line break fault exists in the balancing circuit, the control module 140 controls the first switch K1 to open and the second switch K2 to close. The control module 140 obtains the voltage value of the second resistor R2 and compares the voltage value of the second resistor R2 with the undervoltage threshold value during a line break fault. When the voltage value of the second resistor R2 is less than the undervoltage threshold value during a line break fault, it can be determined that there is no line break fault in the balancing circuit; when the voltage value of the second resistor R2 is greater than or equal to the undervoltage threshold value during a line break fault, it can be determined that there is a line break fault in the balancing circuit. In this way, it is possible to quickly and accurately determine whether there is a line break fault in the sampling branch and the balancing circuit.

[0044] According to an embodiment of the present disclosure, as shown in FIG. 2 , the balancing module 110 includes a balancing capacitor C1 connected in parallel to a balancing switch 150 .

[0045] According to one embodiment of the present disclosure, the capacitance of the balancing capacitor C1 is determined by the surge voltage and the heat generated by the surge voltage applied to the balancing circuit.

[0046] Specifically, assuming that the surge voltage is U, the heat generated by the surge voltage on the balancing circuit is W, and the capacitance of the balancing capacitor C1 is C, the voltage U and the heat W can be obtained through detection. Substitute the voltage U and the heat W into the following formula:

[0047] The specific value of the capacitance C of the balancing capacitor C1 can be obtained.

[0048] According to one embodiment of the present disclosure, the first preset time is determined by the internal resistance of the balancing switch 150 and the capacitance of the balancing capacitor C1 .

[0049] Specifically, assuming that the internal resistance of the balancing switch 150 is R and the first preset time is t, the specific value of the first preset time t can be obtained by substituting the internal resistance R of the balancing switch 150 and the capacitance C of the balancing capacitor C1 into the formula: t=5RC.

[0050] According to an embodiment of the present disclosure, as shown in FIG2 , the balancing switch 150 is a MOS transistor.

[0051] Specifically, the on-state internal resistance of the MOS tube is relatively small, typically only a few ohms. Therefore, when the balancing switch 150 is turned on, the electricity stored in the balancing module 110 can be quickly released through the balancing switch 150. The release time is short, which can shorten the sampling and diagnosis cycle, thereby avoiding significant losses caused by low communication efficiency and untimely fault triggering.

[0052] The specific concept of the present disclosure is explained in detail below with reference to FIG. 2 and FIG. 3 .

[0053] As shown in FIG2 , the diagnostic circuit 100 of the power battery is connected to both ends of the nth single cell in the power battery through the sampling line A and the sampling line B. When the surge on the power battery bus is coupled to the sampling line A, the surge is further transmitted to the sampling diagnostic module 130, causing the single cell to falsely report an overvoltage or undervoltage fault. In addition, a large surge causes a large voltage difference between the sampling lines A and B, and the impedance of the balancing loop is relatively lower than the impedance of the sampling branch (the impedance of the balancing loop is tens of ohms, and the impedance of the sampling branch is several thousand ohms). Therefore, the surge preferentially flows through the balancing loop, and the withstand voltage of the balancing switch 150 (MOS tube) is low, and the risk of the balancing switch 150 being broken down is greater. Therefore, a balancing capacitor C1 is generally added between the drain and source of the MOS tube, but based on the chip ADC (Analog to Digital Converter, analog-to-digital converter) sampling frequency and filtering requirements, the balancing capacitor C1 is usually selected from tens of nanofarads, but the effect of low capacitance on surge protection is limited. If the capacitance of the balancing capacitor C1 is adjusted to be large enough, it will affect the subsequent line break diagnosis of the sampling branch and the balancing loop. The specific impact is as follows: FIG3 shows an equivalent circuit diagram of the balancing switch 150 (MOS tube) when it is not conducting during line diagnosis. If the sampling line A is broken, when the sampling diagnosis module 130 performs line diagnosis on the sampling branch, the first switch K1 is closed and the second switch K2 is opened, and the voltage value of the first resistor R1 is read to determine the line break fault. The diagnostic loop of the sampling branch is shown by the dotted arrow loop in FIG3. In order to improve the surge protection and filtering requirements, based on the surge voltage U and the heat W, the sampling diagnosis module 130 performs line diagnosis on the sampling branch. The balancing capacitor C1 has a larger capacitance value. Since the balancing capacitor C1 with a larger capacitance value will store more electricity, when the balancing capacitor C1 discharges the first resistor R1, after a certain period of time, the voltage of the first resistor R1 is still relatively high, higher than the undervoltage threshold value when the sampling line is disconnected, thereby making it impossible to identify the disconnection fault. Similarly, when the balancing diagnosis module 120 performs line diagnosis on the balancing loop, the first switch K1 is opened, the second switch K2 is closed, and the voltage values ​​of the two resistors are read to determine the disconnection fault. The diagnostic loop of the balancing loop is shown as the solid arrow loop in FIG3. Due to the large capacitance value of the balancing capacitor C1, the voltage value of the second resistor R2 is also relatively high, higher than the undervoltage threshold value when the disconnection fault occurs, thereby making it impossible to identify the disconnection fault. As can be seen from this, the large capacitance of the balancing capacitor C1 solves the problems of device damage and unstable sampling caused by surge impacts. However, it also causes the balancing capacitor C1 to continuously discharge the first resistor R1 or the second resistor R2 during the diagnosis of the sampling branch and the balancing loop open line. This causes the voltage of the first resistor R1 or the second resistor R2 to be relatively high and the discharge time to be long. As a result, the diagnostic circuit cannot diagnose the line break fault within the demand cycle, resulting in low communication efficiency and untimely fault triggering, causing significant losses.

[0054] In the power battery diagnostic circuit 100 disclosed herein, a large-capacity balancing capacitor C1 is provided. The capacitance of balancing capacitor C1 is determined by the surge voltage and the heat generated by the surge voltage applied to the balancing circuit. It is significantly higher than the capacitance of a normal filter capacitor, with a tolerance between the two on the order of tens to a hundred times greater. When performing circuit diagnosis on a power battery, the balancing switch 150 in the balancing circuit is first turned on to enable the balancing module 110 to discharge, thereby rapidly discharging the charge in balancing capacitor C1. After the balancing switch 150 remains on for a first preset time, the balancing switch 150 is then turned off. The first preset time is determined by the internal resistance of the balancing switch 150 and the capacitance of the balancing capacitor C1. The balancing diagnostic module 120 and the sampling diagnostic module 130 are then controlled to perform circuit diagnosis on the sampling branch and the balancing circuit. Different from the existing technical solution of adding TVS tubes between sampling ports, this solution can not only meet the requirements of surge absorption, but also has stable sampling and low cost. It strategically adjusts the sampling branch and balancing loop disconnection diagnosis method to solve the problem that the capacitance of the balancing capacitor C1 is large and the disconnection cannot be diagnosed in a short period of time, thereby improving the protection capability and diagnostic reliability of the battery sampling board.

[0055] In summary, according to the diagnostic circuit of the power battery of the embodiment of the present disclosure, when performing circuit diagnosis, the control module controls the balancing switch to be in the on state to discharge the balancing module. After the balancing switch is continuously on for a first preset time, the control module controls the balancing switch to be in the off state, and then controls the balancing diagnostic module and the sampling diagnostic module to perform circuit diagnosis on the sampling branch and the balancing loop. As a result, when performing circuit diagnosis, the circuit can first discharge the balancing module through the balancing switch, and then perform circuit diagnosis on the sampling branch and the balancing loop through the balancing diagnostic module and the sampling diagnostic module. The sampling is stable and low-cost, and the sampling cycle can be shortened, thereby improving the protection capability of the battery cell sampling board and the diagnostic reliability.

[0056] Corresponding to the above embodiment, the present disclosure also proposes a control method for a diagnostic circuit of a power battery.

[0057] FIG4 is a flowchart of a method for controlling a diagnostic circuit of a power battery according to an embodiment of the present disclosure.

[0058] As shown in FIG4 , the control method of the diagnostic circuit of the power battery according to the embodiment of the present disclosure may include the following steps:

[0059] S1, when performing circuit diagnosis on the power battery, controlling the balancing switch in the balancing circuit to be in the on state to enable the balancing module to discharge, and controlling the balancing switch to be in the off state after the balancing switch is continuously on for a first preset time.

[0060] S2, controls the balancing diagnosis module and the sampling diagnosis module to perform line diagnosis on the sampling branch and the balancing loop.

[0061] According to an embodiment of the present disclosure, the method further includes: controlling the first switch to be in a closed state, controlling the second switch to be in an open state, and performing line diagnosis according to the voltage value of the first resistor.

[0062] According to an embodiment of the present disclosure, the method further includes: controlling the first switch to be in an open state, and controlling the second switch to be in a closed state, so as to perform circuit diagnosis according to the voltage value of the second resistor.

[0063] It should be noted that for details not disclosed in the control method of the diagnostic circuit of the power battery in the embodiment of the present disclosure, please refer to the details disclosed in the diagnostic circuit of the power battery in the embodiment of the present disclosure, and the details will not be repeated here.

[0064] According to the control method for the diagnostic circuit of a power battery according to an embodiment of the present disclosure, when performing circuit diagnosis on a sampling branch power battery, the balancing switch in the balancing circuit is first controlled to be in the on state to enable the balancing module to discharge. After the sampling branch balancing switch is continuously on for a first preset time, the sampling branch balancing switch is controlled to be in the off state. Then, the balancing diagnostic module and the sampling diagnostic module are controlled to perform circuit diagnosis on the sampling branch and the sampling branch balancing circuit. As a result, when performing circuit diagnosis, the method can first discharge the balancing module through the balancing switch, and then perform circuit diagnosis on the sampling branch and the balancing circuit through the balancing diagnostic module and the sampling diagnostic module. The sampling is stable and low-cost, and the sampling cycle can be shortened, thereby improving the protection capability and diagnostic reliability of the battery cell sampling board.

[0065] Corresponding to the above embodiments, the present disclosure also proposes a power battery.

[0066] FIG5 is a block diagram of a power battery according to an embodiment of the present disclosure.

[0067] As shown in FIG. 5 , the power battery 200 according to the embodiment of the present disclosure includes: at least one single battery cell 210 , and the above-mentioned power battery diagnostic circuit 100 provided corresponding to each single battery cell 210 .

[0068] According to the power battery of the embodiment of the present disclosure, through the above-mentioned diagnostic circuit of the power battery, when performing line diagnosis, the balancing module can be discharged through the balancing switch first, and then the sampling branch and the balancing loop can be diagnosed through the balancing diagnostic module and the sampling diagnostic module. The sampling is stable and low-cost, and the sampling cycle can be shortened, thereby improving the protection capability and diagnostic reliability of the battery cell sampling board.

[0069] It should be noted that the logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0070] It should be understood that various parts of the present disclosure can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0071] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0072] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0073] In this disclosure, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components, unless otherwise expressly limited. Those skilled in the art will understand the specific meanings of the above terms in this disclosure based on specific circumstances.

[0074] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A diagnostic circuit for a power battery, comprising: A balancing module, a balancing diagnostic module, a sampling diagnostic module and a control module, wherein the balancing module and the balancing diagnostic module are connected in parallel with the balancing switch in the balancing circuit, and the control module is connected to the balancing switch, the balancing diagnostic module and the sampling diagnostic module respectively, wherein: The control module is configured to control the balancing switch to be in an on state during circuit diagnosis to discharge the balancing module, and to control the balancing switch to be in an off state after the balancing switch is continuously on for a first preset time, and to control the balancing diagnosis module and the sampling diagnosis module to perform circuit diagnosis on the sampling branch and the balancing loop.

2. The diagnostic circuit of the power battery according to claim 1, wherein: The sampling diagnosis module includes: a first switch and a first resistor, wherein: One end of the first switch is connected to the first sampling point of the sampling branch, and the other end of the first switch is connected to the second sampling point of the sampling branch via a first resistor.

3. The diagnostic circuit of the power battery according to claim 2, wherein: The balancing diagnosis module includes: a second switch and a second resistor connected in series, wherein: One end of the second switch is connected to one end of the balancing switch, and the other end of the second switch is connected to the other end of the balancing switch via a second resistor.

4. The diagnostic circuit of the power battery according to claim 3, wherein: The control module is further configured to control the first switch to be in a closed state, control the second switch to be in an open state, and perform circuit diagnosis according to the voltage value of the first resistor.

5. The diagnostic circuit of the power battery according to claim 3, wherein: The control module is further configured to control the first switch to be in an open state and control the second switch to be in a closed state, so as to perform circuit diagnosis according to the voltage value of the second resistor.

6. The diagnostic circuit of the power battery according to any one of claims 1 to 5, wherein: The balancing module includes a balancing capacitor connected in parallel with the balancing switch.

7. The diagnostic circuit for a power battery according to claim 6, wherein: The capacitance of the balancing capacitor is determined by the surge voltage and the heat generated by the surge voltage applied to the balancing circuit.

8. The diagnostic circuit for a power battery according to claim 6, wherein: The first preset time is determined by the internal resistance of the balancing switch and the capacitance of the balancing capacitor.

9. The diagnostic circuit for a power battery according to claim 1, wherein: The balancing switch is a MOS tube.

10. A method for controlling a diagnostic circuit of a power battery according to any one of claims 1 to 9, the method comprising: When performing circuit diagnosis on the power battery, controlling the balancing switch in the balancing circuit to be in an on state so that the balancing module can discharge, and controlling the balancing switch to be in an off state after the balancing switch is continuously on for a first preset time; The balancing diagnosis module and the sampling diagnosis module are controlled to perform line diagnosis on the sampling branch and the balancing loop.

11. A power battery comprising: At least one single battery cell, and a diagnostic circuit for the power battery according to any one of claims 1 to 9, arranged corresponding to each single battery cell.

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