Diagnosis circuit of power battery, control method thereof and power battery

Abstract

The application discloses a diagnosis circuit of a power battery, a control method of the diagnosis circuit and the power battery. The diagnosis circuit of the power battery comprises an equalization module, an equalization diagnosis module, a sampling diagnosis module and a control module. The equalization module and the equalization diagnosis module are connected in parallel with an equalization switch in an equalization loop. The control module is connected with the equalization module, the equalization diagnosis module and the sampling diagnosis module respectively. The control module is used for controlling the equalization switch to be in a conduction state to make the equalization module discharge when line diagnosis is performed. The control module is used for controlling the equalization switch to be in a disconnection state after the equalization switch is continuously conducted for a first preset time. The control module is used for controlling the equalization diagnosis module and the sampling diagnosis module to perform line diagnosis on a sampling branch and the equalization loop. The diagnosis circuit of the embodiment of the application is stable in sampling, low in cost, short in sampling period, high in protection capability of a battery cell sampling board and high in diagnosis reliability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power batteries, in particular to a diagnosis circuit of a power battery, a control method of the diagnosis circuit of the power battery and a power battery. BACKGROUND

[0002] Currently, with the development trend of the 800V or even higher power voltage platform of electric vehicles and the power improvement of inductive load driving motors, the voltage surge interference on the power battery bus is obviously increased. These surge interferences on the bus are distributed to the cell sampling board of the BMS (Battery Management System, battery management system) through the cell sampling harness, causing unstable sampling of the sampling board; in addition, the over-high surge can pass through the low-impedance balancing loop first through the sampling line, easily causing the overvoltage damage of the built-in MOS (Metal Oxide Semiconductor, metal oxide semiconductor) tube on the balancing loop of the sampling board, further causing the over-discharge of the cell.

[0003] In order to prevent the surge impact on the power battery bus of the high-voltage platform from being transmitted to the cell sampling board of the BMS along the cell sampling line, further affecting the sampling error, the balancing function and the sampling line breakage diagnosis, there are few effective response schemes for the application of the high-voltage platform at present, and the solutions are mostly implemented from the source and the path. In the related art, considering the diversity of the power battery load and the working scene, it is costly to eliminate the surge based on the power battery load end and the charging pile from the source, and it is difficult to completely eliminate it in general engineering design; from the path, a TVS (Transient Voltage Suppressor, transient voltage suppression diode) protection tube is added to each sampling (balancing) channel to prevent the surge from damaging the low-impedance balancing loop, and the sampling filtering time is increased in the software, so that a more accurate cell sampling voltage value can be obtained, but these operations on the one hand bring a sharp rise in the cost of individual pieces, and on the other hand sacrifice the performance of the sampling function, prolong the sampling period and reduce the real-time data. SUMMARY

[0004] The present application aims to at least solve one of the technical problems in the related art. To this end, the first object of the present application is to provide a diagnosis circuit of a power battery, which can first discharge the balancing module through the balancing switch when performing line diagnosis, and then perform line diagnosis on the sampling branch and the balancing loop through the balancing diagnosis module and the sampling diagnosis module, so as to stabilize the sampling, reduce the cost, shorten the sampling period, and improve the protection capability and diagnosis reliability of the cell sampling board.

[0005] The second object of the present application is to provide a control method of the diagnosis circuit of the power battery.

[0006] The third object of the present application is to provide a power battery.

[0007] To achieve the above object, the first aspect of the present application provides a diagnosis circuit of a power battery, comprising: an equalization module, an equalization diagnosis module, a sampling diagnosis module and a control module, the equalization module and the equalization diagnosis module are connected in parallel with an equalization switch in an equalization loop, the control module is connected with the equalization switch, the equalization diagnosis module and the sampling diagnosis module respectively, wherein the control module is used to control the equalization switch to be in a conducting state to make the equalization module discharge when line diagnosis is performed, and control the equalization switch to be in a disconnecting state after the equalization switch is continuously conducted for a first preset time, and control the equalization diagnosis module and the sampling diagnosis module to perform line diagnosis on the sampling branch and the equalization loop.

[0008] The diagnosis circuit of the power battery according to the embodiment of the present application, when line diagnosis is performed, the control module controls the equalization switch to be in a conducting state to make the equalization module discharge, and controls the equalization switch to be in a disconnecting state after the equalization switch is continuously conducted for a first preset time, and then controls the equalization diagnosis module and the sampling diagnosis module to perform line diagnosis on the sampling branch and the equalization loop. Thus, when line diagnosis is performed, the circuit can first make the equalization module discharge through the equalization switch, and then perform line diagnosis on the sampling branch and the equalization loop through the equalization diagnosis module and the sampling diagnosis module, so that the sampling is stable, the cost is low, the sampling period can be shortened, and the protection ability of the cell sampling board and the diagnosis reliability can be improved.

[0009] In addition, the diagnosis circuit of the power battery according to the above embodiment of the present application can also have the following additional technical features:

[0010] According to an embodiment of the present application, the sampling diagnosis module comprises: a first switch and a first resistor, wherein one end of the first switch is connected with a first sampling point of the sampling branch, and the other end of the first switch is connected with a second sampling point of the sampling branch through the first resistor.

[0011] According to an embodiment of the present application, the equalization diagnosis module comprises: a second switch and a second resistor connected in series, wherein one end of the second switch is connected with one end of the equalization switch, and the other end of the second switch is connected with the other end of the equalization switch through the second resistor.

[0012] According to an embodiment of the present application, the control module is further used to control the first switch to be in a closed state, control the second switch to be in a disconnecting state, and perform line diagnosis according to the voltage value of the first resistor.

[0013] According to one embodiment of the present application, 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 to perform line diagnosis according to the voltage value of the second resistor.

[0014] According to one embodiment of the present application, the equalization module comprises an equalization capacitor connected in parallel with the equalization switch.

[0015] According to one embodiment of the present application, the capacitance of the equalization capacitor is determined by the surge voltage and the heat generated by the surge voltage on the equalization loop.

[0016] According to one embodiment of the present application, the first preset time is determined by the internal resistance of the equalization switch and the capacitance of the equalization capacitor.

[0017] According to one embodiment of the present application, the equalization switch is a MOS tube.

[0018] To achieve the above object, the second aspect of the present application provides a control method of the above-mentioned diagnosis circuit of the power battery, which comprises: when performing line diagnosis on the power battery, controlling the equalization switch in the equalization loop to be in a conducting state to make the equalization module discharge, and after the equalization switch is continuously conducting for a first preset time, controlling the equalization switch to be in an open state; controlling the equalization diagnosis module and the sampling diagnosis module to perform line diagnosis on the sampling branch and the equalization loop.

[0019] The control method of the diagnosis circuit of the power battery according to the embodiment of the present application, when performing line diagnosis on the sampling branch power battery, first controls the equalization switch in the equalization loop to be in a conducting state to make the equalization module discharge, and after the sampling branch equalization switch is continuously conducting for a first preset time, controls the sampling branch equalization switch to be in an open state, and then controls the equalization diagnosis module and the sampling diagnosis module to perform line diagnosis on the sampling branch and the sampling branch equalization loop. Thus, the method can, when performing line diagnosis, first discharge the equalization module through the equalization switch, and then perform line diagnosis on the sampling branch and the equalization loop through the equalization diagnosis module and the sampling diagnosis module, so that the sampling is stable, the cost is low, the sampling period can be shortened, and the protection ability and diagnosis reliability of the cell sampling board can be improved.

[0020] To achieve the above object, the third aspect of the present application provides a power battery, which comprises: at least one single cell, and the above-mentioned diagnosis circuit of the power battery arranged corresponding to each single cell.

[0021] The power battery according to the embodiment of the present application can discharge the equalization module through the equalization switch, and then perform line diagnosis on the sampling branch and the equalization loop through the equalization diagnosis module and the sampling diagnosis module when performing line diagnosis, so that the sampling is stable, the cost is low, the sampling period can be shortened, and the protection capability and the diagnosis reliability of the cell sampling board can be improved.

[0022] Additional aspects and advantages of the present application will be described in the following description, will become apparent from the following description, or will be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 A block schematic diagram of the diagnosis circuit of the power battery according to an embodiment of the present application is shown in FIG. 1.

[0024] Figure 2 A topological schematic diagram of the diagnosis circuit of the power battery according to an embodiment of the present application is shown in FIG. 2.

[0025] Figure 3 An equivalent circuit diagram of the equalization switch according to an embodiment of the present application when not conducting during line diagnosis is shown in FIG. 3.

[0026] Figure 4 A flow chart of the control method of the diagnosis circuit of the power battery according to an embodiment of the present application is shown in FIG. 4.

[0027] Figure 5 A block schematic diagram of the power battery according to an embodiment of the present application is shown in FIG. 5. DETAILED DESCRIPTION

[0028] The embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary, and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0029] The diagnosis circuit of the power battery, the control method of the diagnosis circuit of the power battery and the power battery according to the embodiments of the present application are described below with reference to the accompanying drawings.

[0030] Figure 1 A block schematic diagram of the diagnosis circuit of the power battery according to an embodiment of the present application is shown in FIG. 1.

[0031] As Figure 1As shown, the diagnosis circuit 100 of the power battery includes an equalization module 110, an equalization diagnosis module 120, a sampling diagnosis module 130, and a control module 140. The equalization module 110 and the equalization diagnosis module 120 are connected in parallel with an equalization switch 150 in an equalization loop. The control module 140 is connected with the equalization switch 150, the equalization diagnosis module 120, and the sampling diagnosis module 130, respectively. When performing line diagnosis, the control module 140 controls the equalization switch 150 to be in a conducting state, so that the equalization module 110 discharges, and after the equalization switch 150 is continuously conducting for a first preset time, the control module 140 controls the equalization switch 150 to be in a non-conducting state, and controls the equalization diagnosis module 120 and the sampling diagnosis module 130 to perform line diagnosis on the sampling branch and the equalization loop.

[0032] Specifically, as shown, Figure 1 The diagnosis circuit 100 of the power battery is connected to both ends of the nth single battery cell in the power battery through a sampling line A and a sampling line B. The sampling diagnosis module 130 can sample the voltage at both ends of the single battery cell through the sampling line A and the sampling line B, and transmit the sampling value to the BMS of the single battery. The BMS determines whether equalization is needed according to the voltage value of each single battery cell. When a surge on the power battery bus is coupled to the sampling line A and then transmitted to the sampling diagnosis module 130, the single battery cell is misreported as overvoltage or undervoltage failure. In addition, a large surge causes a large voltage difference between the sampling line A and the sampling line B, and the impedance of the equalization loop is relatively lower than the impedance of the sampling branch (the impedance of the equalization loop is tens of ohms, and the impedance of the sampling branch is thousands of ohms). Therefore, the surge preferentially flows through the equalization loop, and the equalization switch 150 is at a high risk of being broken down. The equalization module 110 can absorb a high surge voltage, thereby avoiding unstable sampling of the sampling diagnosis module 130 and avoiding breakdown of the equalization switch 150.

[0033] When performing line diagnosis to determine whether there is a broken line fault in the line, the control module 140 controls the equalization switch 150 to be in a conducting state, so that the electric quantity stored in the equalization module 110 is discharged through the equalization switch 150. After the equalization switch 150 is continuously conducting for a first preset time, the control module 140 controls the equalization switch 150 to be in a non-conducting state, and then controls the equalization diagnosis module 120 to perform line diagnosis on the equalization loop to determine whether there is a broken line fault in the equalization loop, and controls the sampling diagnosis module 130 to perform line diagnosis on the sampling branch to determine whether there is a broken line fault in the sampling branch.

[0034] Therefore, the diagnosis circuit of the power battery can discharge the equalization module through the equalization switch before line diagnosis, and then perform line diagnosis on the sampling branch and the equalization loop through the equalization diagnosis module and the sampling diagnosis module, so that the sampling is stable, the cost is low, the sampling period can be shortened, and the protection capability and diagnosis reliability of the cell sampling board are improved.

[0035] According to one embodiment of the present application, as shown in Figure 2 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 with the first sampling point of the sampling branch, and the other end of the first switch K1 is connected with the second sampling point of the sampling branch through the first resistor R1.

[0036] According to one embodiment of the present application, as shown in Figure 2 The equalization diagnosis 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 with one end of the equalization switch 150, and the other end of the second switch K2 is connected with the other end of the equalization switch 150 through the second resistor R2.

[0037] According to one embodiment of the present application, 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 line diagnosis according to the voltage value of the first resistor R1.

[0038] According to one embodiment of the present application, the control module 140 is further configured to control the first switch K1 to be in an open state, control the second switch K2 to be in a closed state, and perform line diagnosis according to the voltage value of the second resistor R2.

[0039] Specifically, when performing line diagnosis to determine whether there is a disconnection fault in the line, the control module 140 controls the equalization switch 150 to be conductive, so that the electric quantity stored in the equalization module 110 is discharged through the equalization switch 150. After the equalization switch 150 is continuously conductive for a first preset time, the control module 140 controls the equalization switch 150 to be non-conductive. When the sampling diagnosis module 130 performs line diagnosis on the sampling branch to determine whether there is a disconnection 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 acquires the voltage value of the first resistor R1, and compares the voltage value of the first resistor R1 with an under-voltage threshold value when the sampling line is disconnected. When the voltage value of the first resistor R1 is less than the under-voltage threshold value when the sampling line is disconnected, it can be determined that there is no disconnection fault in the sampling branch. When the voltage value of the first resistor R1 is greater than or equal to the under-voltage threshold value when the sampling line is disconnected, it can be determined that there is a disconnection fault in the sampling branch.

[0040] Further, when the equalization diagnosis module 120 performs line diagnosis on the equalization loop to determine whether there is a disconnection fault in the equalization loop, the control module 140 controls the first switch K1 to be open and controls the second switch K2 to be closed, the control module 140 acquires the voltage value of the second resistor R2, and compares the voltage value of the second resistor R2 with the under-voltage threshold value in the disconnection fault, when the voltage value of the second resistor R2 is less than the under-voltage threshold value in the disconnection fault, it can be determined that there is no disconnection fault in the equalization loop; when the voltage value of the second resistor R2 is greater than or equal to the under-voltage threshold value in the disconnection fault, it can be determined that there is a disconnection fault in the equalization loop. Thus, it can be quickly and accurately determined whether there is a disconnection fault in the sampling branch and the equalization loop.

[0041] According to one embodiment of the present application, as shown in Figure 2 The equalization module 110 includes an equalization capacitor C1 connected in parallel with the equalization switch 150.

[0042] According to one embodiment of the present application, the capacitance of the equalization capacitor C1 is determined by the surge voltage and the heat generated by the surge voltage applied to the equalization loop.

[0043] Specifically, assuming that the voltage value of the surge voltage is U, the heat generated by the surge voltage applied to the equalization loop is W, and the capacitance of the equalization capacitor C1 is C, wherein the voltage value U and the heat W can be obtained by detection, and the voltage value U and the heat W are substituted into the following formula:

[0044]

[0045] The specific value of the capacitance C of the equalization capacitor C1 can be obtained.

[0046] According to one embodiment of the present application, the first preset time is determined by the internal resistance of the equalization switch 150 and the capacitance of the equalization capacitor C1.

[0047] Specifically, assuming that the internal resistance of the equalization switch 150 is R and the first preset time is t, the internal resistance R of the equalization switch 150 and the capacitance C of the equalization capacitor C1 are substituted into the formula: t=5RC to obtain the specific value of the first preset time t.

[0048] According to one embodiment of the present application, as shown in Figure 2 The equalization switch 150 is a MOS tube.

[0049] Specifically, the on-resistance of the MOS tube is small, usually only a few ohms, so when the equalization switch 150 is turned on, the amount of electricity stored in the equalization module 110 can be quickly released through the equalization switch 150, the release time is short, the sampling and diagnosis period can be reduced, and thus major losses caused by low communication efficiency and untimely fault triggering can be avoided.

[0050] The following is combined with Figure 2 and Figure 3 The specific concept of this invention will be explained in detail.

[0051] like Figure 2 As shown, the diagnostic circuit 100 of the power battery is connected to the two ends of the nth single cell in the power battery through sampling lines A and B. When a surge on the power battery bus is coupled to sampling line A, the surge is then transmitted to the sampling diagnostic module 130, causing the single cell to falsely report overvoltage or undervoltage faults. In addition, a large surge causes a large voltage difference between sampling lines A and B, and the impedance of the equalization circuit is relatively lower than that of the sampling branch (the impedance of the equalization circuit is tens of ohms, while the impedance of the sampling branch is several thousand ohms). Therefore, the surge preferentially flows into the equalization circuit. However, the equalization switch 150 (MOSFET) has a low withstand voltage, and the equalization switch 150 is at high risk of breakdown. Therefore, an equalization capacitor C1 is usually added between the drain and source of the MOSFET. However, based on the chip ADC (Analog to Digital)... The sampling frequency and filtering requirements of the converter (analog-to-digital converter) dictate that the equalization capacitor C1 is typically chosen in the tens of nanofarads range. However, low capacitance values ​​offer limited protection against surges. Increasing the capacitance of C1 to a sufficiently large value will affect the disconnection diagnosis of subsequent sampling branches and equalization circuits. Specifically, the impact is as follows: Figure 3 The diagram shown is the equivalent circuit diagram of the equalization switch 150 (MOSFET) not conducting during line diagnosis. If sampling line A is broken, when the sampling diagnosis module 130 performs line diagnosis on the sampling branch, the first switch K1 is closed, the second switch K2 is open, and the voltage value of the first resistor R1 is read to determine the open circuit fault. The diagnostic circuit of the sampling branch is as follows: Figure 3 As shown by the dashed arrow loop, to improve surge protection and filtering requirements, a larger capacitance value is used for the balancing capacitor C1 based on the surge voltage U and heat W. This larger capacitance value means the balancing capacitor C1 stores more charge. Consequently, when the balancing capacitor C1 discharges through the first resistor R1, the voltage across R1 remains high even after a certain discharge time, exceeding the undervoltage threshold for a sampling line open circuit fault. This prevents the open circuit fault from being identified. Similarly, when the balancing diagnostic module 120 performs line diagnostics on the balancing circuit, the first switch K1 is open, the second switch K2 is closed, and the voltage values ​​of the two resistors are read to determine the open circuit fault. The diagnostic circuit of the balancing circuit is as follows: Figure 3As shown by the solid arrow loop in the figure, due to the large capacitance value of the equalization capacitor C1, the voltage value of the second resistor R2 is also high, which is higher than the under-voltage threshold value in the broken wire fault, thereby causing the broken wire fault to be unable to be identified. As can be seen, due to the large capacitance value of the equalization capacitor C1, the problems of device damage and unstable sampling caused by surge impact are solved, but the equalization capacitor C1 continuously discharges the first resistor R1 or the second resistor R2 during the open line diagnosis of the sampling branch and the equalization loop, which causes the voltage of the first resistor R1 or the second resistor R2 to be high and the discharge time to be long, thereby causing the diagnosis circuit to be unable to diagnose the broken wire fault in the required period, and further causing low communication efficiency, untimely fault triggering, and significant loss.

[0052] In the diagnosis circuit 100 of the power battery, a large-capacity equalization capacitor C1 is arranged, the capacitance value of the equalization capacitor C1 is determined by the surge voltage and the heat generated by the surge voltage applied to the equalization loop, and is much higher than the capacitance value of a normal filter capacitor, and the capacitance difference is in the order of tens to one hundred times. During line diagnosis of the power battery, the equalization switch 150 in the equalization loop is first controlled to be in a conducting state, so that the equalization module 110 discharges, so that the electric quantity in the equalization capacitor C1 is quickly discharged, and after the equalization switch 150 is continuously conducted for a first preset time, the equalization switch 150 is controlled to be in a disconnected state, wherein the first preset time is determined by the internal resistance of the equalization switch 150 and the capacitance value of the equalization capacitor C1, and then the equalization diagnosis module 120 and the sampling diagnosis module 130 are controlled to diagnose the line of the sampling branch and the equalization loop. Different from the technical solution of adding a TVS tube between the sampling ports in the prior art, the surge absorption can be met, the sampling is stable, and the cost is low; the sampling branch and the equalization loop broken wire diagnosis method is adjusted in strategy, the problem that the large capacitance value of the equalization capacitor C1 cannot be diagnosed in a short period is solved, and the protection capability and diagnosis reliability of the cell sampling board are improved.

[0053] In summary, according to the diagnosis circuit of the power battery in the embodiment of the present application, during line diagnosis, the control module controls the equalization switch to be in a conducting state, so that the equalization module discharges, and after the equalization switch is continuously conducted for a first preset time, the equalization switch is controlled to be in a disconnected state, and then the equalization diagnosis module and the sampling diagnosis module are controlled to diagnose the line of the sampling branch and the equalization loop. Thus, the circuit can first discharge the equalization module through the equalization switch during line diagnosis, and then diagnose the line of the sampling branch and the equalization loop through the equalization diagnosis module and the sampling diagnosis module, so that the sampling is stable, the cost is low, the sampling period is shortened, and the protection capability and diagnosis reliability of the cell sampling board are improved.

[0054] Corresponding to the above-mentioned embodiment, the present application also proposes a control method of a diagnosis circuit of a power battery.

[0055] Figure 4 A flow chart of a control method of a diagnosis circuit of a power battery according to an embodiment of the present application.

[0056] As shown in Figure 4 The control method of the diagnosis circuit of the power battery according to the embodiment of the present application can include the following steps:

[0057] S1, when performing line diagnosis on the power battery, controlling the equalization switch in the equalization loop to be in a conducting state to make the equalization module discharge, and after the equalization switch is continuously conducting for a first preset time, controlling the equalization switch to be in a disconnected state.

[0058] S2, controlling the equalization diagnosis module and the sampling diagnosis module to perform line diagnosis on the sampling branch and the equalization loop.

[0059] According to one embodiment of the present application, the above-mentioned method further includes: controlling the first switch to be in a closed state and controlling the second switch to be in a disconnected state, and performing line diagnosis according to the voltage value of the first resistor.

[0060] According to one embodiment of the present application, the above-mentioned method further includes: controlling the first switch to be in a disconnected state and controlling the second switch to be in a closed state to perform line diagnosis according to the voltage value of the second resistor.

[0061] It should be noted that the details not disclosed in the control method of the diagnosis circuit of the power battery according to the embodiment of the present application are referred to the details disclosed in the diagnosis circuit of the power battery according to the embodiment of the present application, which will not be described here.

[0062] The control method of the diagnosis circuit of the power battery according to the embodiment of the present application, when performing line diagnosis on the sampling branch power battery, first controls the equalization switch in the equalization loop to be in a conducting state to make the equalization module discharge, and after the equalization switch in the sampling branch is continuously conducting for a first preset time, controls the equalization switch in the sampling branch to be in a disconnected state, and then controls the equalization diagnosis module and the sampling diagnosis module to perform line diagnosis on the sampling branch and the equalization loop of the sampling branch. Therefore, when performing line diagnosis, the method can first discharge the equalization module through the equalization switch, and then perform line diagnosis on the sampling branch and the equalization loop through the equalization diagnosis module and the sampling diagnosis module. The sampling is stable, the cost is low, the sampling period can be shortened, and the protection ability and diagnosis reliability of the battery cell sampling board can be improved.

[0063] Corresponding to the above-mentioned embodiment, the present application further provides a power battery.

[0064] Figure 5 A block diagram of a power battery according to an embodiment of the present application.

[0065] As shown in Figure 5As shown, the power battery 200 of this embodiment includes: at least one single cell 210, and the above-mentioned power battery diagnostic circuit 100 provided corresponding to each single cell 210.

[0066] According to the power battery of the present invention, through the above-mentioned power battery diagnostic circuit, when performing line diagnosis, the equalization module is first discharged through the equalization switch, and then the sampling branch and equalization circuit are diagnosed through the equalization diagnostic module and the sampling diagnostic module. The sampling is stable and the cost is low, and the sampling cycle can be shortened, thereby improving the protection capability of the cell sampling board and the diagnostic reliability.

[0067] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing 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 (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0068] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0069] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0070] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0071] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and other terms should be understood in a broad sense, for example, can be fixedly connected, can also be detachably connected, or integrated; can be mechanically connected, can also be electrically connected; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0072] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A diagnostic circuit for a power cell, characterized in that The diagnostic circuit of the power battery comprises: a balancing module, a balancing diagnosis module, a sampling diagnosis module and a control module, the balancing module and the balancing diagnosis module are connected in parallel with a balancing switch in a balancing loop, and the control module is connected with the balancing switch, the balancing diagnosis module and the sampling diagnosis module respectively, wherein the control module is configured to control the balancing switch to be in a conducting state to make the balancing module discharge when line diagnosis is performed, control the balancing switch to be in a disconnecting state after the balancing switch is continuously conducted for a first preset time, and control the balancing diagnosis module and the sampling diagnosis module to perform line diagnosis on a sampling branch and the balancing loop.

2. The diagnostic circuit of a power cell according to claim 1, characterized in that The sampling diagnosis module comprises a first switch and a first resistor, wherein one end of the first switch is connected with a first sampling point of the sampling branch, and the other end of the first switch is connected with a second sampling point of the sampling branch through the first resistor.

3. The diagnostic circuit of a power cell according to claim 2, characterized in that The balancing diagnosis module comprises a second switch and a second resistor connected in series, wherein one end of the second switch is connected with one end of the balancing switch, and the other end of the second switch is connected with the other end of the balancing switch through the second resistor.

4. The diagnostic circuit of a power cell according to claim 3, characterized in that The control module is further configured to control the first switch to be in a closed state, control the second switch to be in a disconnecting state, and perform line diagnosis according to a voltage value of the first resistor.

5. The diagnostic circuit of a power cell according to claim 3, characterized in that, The control module is further configured to control the first switch to be in a disconnecting state, control the second switch to be in a closed state, and perform line diagnosis according to a voltage value of the second resistor.

6. The diagnostic circuit of a power cell according to any one of claims 1-5, characterized in that, The balancing module comprises a balancing capacitor connected in parallel with the balancing switch.

7. The diagnostic circuit of a power cell according to claim 6, characterized in that The capacitance of the balancing capacitor is determined by a surge voltage and heat generated by the surge voltage applied on the balancing loop.

8. The diagnostic circuit of a power cell according to claim 6, characterized in that, The first preset time is determined by an internal resistance of the balancing switch and the capacitance of the balancing capacitor.

9. The diagnostic circuit of a power cell according to claim 1, characterized in that, The balancing switch is a MOS tube.

10. A method of controlling a diagnostic circuit of a power cell according to any one of claims 1 to 9, characterized in that The method comprises: controlling a balancing switch in a balancing loop to be in a conducting state to make a balancing module discharge when line diagnosis is performed on the power battery, and controlling the balancing switch to be in a disconnecting state after the balancing switch is continuously conducted for a first preset time; controlling a balancing diagnosis module and a sampling diagnosis module to perform line diagnosis on a sampling branch and the balancing loop.

11. A power cell, characterized by The diagnostic circuit of the power battery comprises: at least one single cell and a diagnostic circuit of the power battery as claimed in any one of claims 1-9 arranged corresponding to each single cell.

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