Detection circuit, battery pack and battery management system

Abstract

The invention provides a detection circuit, a battery pack and a battery management system. The detection circuit is used for detecting a connection circuit of a first battery in a plurality of batteries connected in series. The detection circuit comprises a self-checking resistor; the equalization circuit comprises an equalization switch, and the equalization circuit is connected in series with the first battery through a self-check resistor; the filter circuit comprises a filter capacitor, and the filter circuit is connected with the equalization circuit in parallel; the sampling chip is connected with the two ends of the filter capacitor, the sampling chip, the filter circuit and the self-checking resistor jointly form a sampling circuit of the first battery, the sampling chip is used for determining whether the sampling circuit of the first battery fails or not according to a first voltage and a second voltage, the first voltage is the voltage on the filter capacitor when the equalization switch is switched off, and the second voltage is the voltage on the filter capacitor when the equalization switch is switched off; and the second voltage is the voltage on the filter capacitor when the equalization switch is closed. The detection circuit reduces the diagnosis cost and the overall size.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and particularly to a detection circuit, a battery pack, and a battery management system. Background Art

[0002] In order to meet the requirements of various complex applications, such as providing a higher output voltage, a larger energy storage capacity, or a larger power, multiple single cells (or called battery cores) are usually connected in series to form a battery pack. In order to accurately control each single cell in the battery pack, a sampling circuit is usually added to sample each battery, and the state of the battery is monitored based on the sampled data, so as to ensure the safety of the battery pack.

[0003] However, the sampling circuit may fail due to hardware failures, design defects, improper operations, etc. The failure of the sampling circuit will lead to inaccurate collected data, and then affect the system reliability and safety. For example, some key safety signals may be missed, such as overcharging or over-discharging, which may cause the battery to catch fire or be damaged.

[0004] In order to diagnose whether the sampling circuit fails, it is usually necessary to backup the sampling, that is, two identical sampling circuits are used to sample the same battery, and the sampling results are compared with each other for self-check diagnosis of the sampling. However, this method is costly and occupies a large board area. Summary of the Invention

[0005] The present application provides a detection circuit, a battery pack, and a battery management system. The following aspects involved in the present application are introduced.

[0006] In a first aspect, a detection circuit is provided. The detection circuit is used to detect the connection circuit of a first battery among a plurality of serially connected batteries. The detection circuit includes: a self-check resistor; a balancing circuit including a balancing switch, and the balancing circuit is serially connected to the first battery through the self-check resistor; a filtering circuit including a filtering capacitor, and the filtering circuit is connected in parallel with the balancing circuit; a sampling chip connected to both ends of the filtering capacitor. The sampling chip, the filtering circuit, and the self-check resistor together form the sampling circuit of the first battery. The sampling chip is configured to: determine whether the sampling circuit of the first battery fails according to a first voltage and a second voltage, where the first voltage is the voltage on the filtering capacitor when the balancing switch is turned off, and the second voltage is the voltage on the filtering capacitor when the balancing switch is turned on.

[0007] Optionally, the sampling chip is configured to: determine whether the first voltage and the second voltage satisfy a first preset rule; in response to the first voltage and the second voltage satisfying the first preset rule, determine that the sampling circuit of the first battery is normal; in response to the first voltage and the second voltage not satisfying the first preset rule, determine that the sampling circuit of the first battery fails.

[0008] Optionally, the sampling chip is further configured to: before determining whether the sampling circuit of the first battery fails according to the first voltage and the second voltage, determine whether the balancing circuit fails according to the first voltage and the second voltage.

[0009] Optionally, the sampling chip is configured to: before determining whether the sampling circuit of the first battery fails according to the first voltage and the second voltage, determine whether the first voltage and the second voltage satisfy a second preset rule; in response to the first voltage and the second voltage satisfying the second preset rule, determine that the balancing circuit is normal; in response to the voltage and the second voltage not satisfying the second preset rule, determine that the balancing circuit fails.

[0010] Optionally, the second preset rule is that the absolute value of the difference between the first voltage and the second voltage is greater than a first preset value.

[0011] Optionally, the self-checking resistor includes a first self-checking resistor connected to the positive electrode of the first battery and a second self-checking resistor connected to the negative electrode of the first battery. The balancing circuit further includes a first balancing resistor and a second balancing resistor. One end of the first balancing resistor is connected in series with the first self-checking resistor, and the other end of the first balancing resistor is connected in series with one end of the balancing switch. One end of the second balancing resistor is connected in series with the second self-checking resistor, and the other end of the second balancing resistor is connected in series with the other end of the balancing switch. The first preset rule is: |Second voltage / (First balancing resistor + Second balancing resistor) * (First self-checking resistor + Second self-checking resistor + First balancing resistor + Second balancing resistor) - First voltage| < Second preset value.

[0012] Optionally, the sampling chip is configured to: control the acquisition of the first voltage on the filter capacitor when the balancing switch is off; control the balancing switch to switch from the off state to the on state and acquire the second voltage on the filter capacitor.

[0013] Optionally, the filtering circuit further includes a first filtering resistor and a second filtering resistor. One end of the first filtering resistor is connected to one end of the filtering capacitor, the other end of the first filtering resistor is connected to the connection point between the first self-checking resistor and the balancing circuit, one end of the second filtering resistor is connected to the other end of the filtering capacitor, and the other end of the second filtering resistor is connected to the connection point between the second self-checking resistor and the balancing circuit.

[0014] In a second aspect, a battery pack is provided, which includes a plurality of batteries connected in series and a plurality of detection circuits as described in the first aspect corresponding to the plurality of batteries one by one.

[0015] In a third aspect, a battery management system is provided, which includes the battery pack as described in the second aspect.

[0016] The detection circuit provided in the embodiment of the present application includes a sampling circuit and a balancing circuit of a first battery. By multiplexing the balancing circuit and adding a self-checking resistor to the sampling circuit of the first battery, it is possible to diagnose whether the sampling circuit of the first battery fails according to the voltage change of the filtering capacitor when the balancing circuit is turned off and on. This method avoids the problem in the prior art that an additional backup sampling circuit is required for failure diagnosis, thereby effectively reducing the diagnosis cost and the overall size of the detection circuit. Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of a battery pack provided by an embodiment of the present application.

[0018] Figure 2 It is a schematic structural diagram of a battery pack provided by another embodiment of the present application.

[0019] Figure 3 It is a schematic flow diagram of a method for detecting a connection circuit of a sampling chip to a first battery provided by an embodiment of the present application. Detailed Embodiments

[0020] For the convenience of understanding the present application, the present application will be described in more detail below based on exemplary embodiments and in combination with the drawings. The same or similar reference numerals are used in the drawings to represent the same or similar modules. It should be understood that the drawings are only schematic, and the protection scope of the present application is not limited thereto.

[0021] In order to accurately control each single battery in the battery pack, a sampling circuit is usually provided in the battery pack to sample each battery through the sampling circuit and monitor the state of the battery based on the sampling data, thereby ensuring the safety of the battery pack. For the convenience of understanding, the following will introduce a battery pack including a sampling circuit in combination with Figure 1 It should be noted that Figure 1In the figure, the battery pack 100 includes three batteries as an example for illustrative description, but the actual batteries included in the battery pack 100 are not limited and can be set as needed.

[0022] like Figure 1 As shown, the battery pack 100 includes a plurality of single cells and a sampling circuit connected to each cell. For example, Figure 1 The battery pack 100 in the embodiment includes a battery B1, a battery B2 and a battery B3, and a sampling circuit of the battery B1, a sampling circuit of the battery B2 and a sampling circuit of the battery B3. Among them, the battery B1, the battery B2 and the battery B3 are connected in series. The sampling chip and the first filter circuit form a sampling circuit of the battery B1. The battery B1 is connected in series with the first filter circuit including the resistor R8, the capacitor C3 and the resistor R14, and the sampling chip is connected to both ends of the capacitor C3 to sample the battery B1 by sampling the voltage or current on the capacitor C3. The sampling chip and the second filter circuit form a sampling circuit of the battery B2. The battery B2 is connected in series with the second filter circuit including the resistor R6, the capacitor C2 and the resistor R8, and the sampling chip is connected to both ends of the capacitor C2 to sample the battery B2 by sampling the voltage or current on the capacitor C2. The sampling chip and the third filter circuit form a sampling circuit of the battery B3. The battery B3 is connected in series with a third filter circuit including a resistor R5, a capacitor C1 and a resistor R6, and the sampling chip is connected to both ends of the capacitor C1 to sample the battery B3 by sampling the voltage or current on the capacitor C1.

[0023] The above sampling circuit may fail due to hardware failure, design defects or improper operation. Failure of the sampling circuit will lead to inaccurate collected data, which will affect the reliability and safety of the system. For example, some key safety signals may be missed, such as overcharging or over-discharging, which will cause the battery to catch fire or be damaged.

[0024] In order to diagnose whether the sampling circuit fails, a backup sampling circuit is usually required, that is, two identical sampling circuits are used to sample the same battery, and the sampling results are compared with each other to perform a self-diagnosis of the sampling. In other words, the sampling circuits of the above-mentioned battery B1, the sampling circuit of B2, and the sampling circuit of the battery B3 will be provided with two sets, and the sampling circuits will be self-checked by comparing the sampling results of the two sets of sampling circuits. However, this method is costly and occupies a large board area.

[0025] In view of this, an embodiment of the present application provides a detection circuit. The detection circuit includes a sampling circuit and an equalization circuit for a first battery. By multiplexing the equalization circuit and adding a self-checking resistor to the sampling circuit of the first battery, it is possible to diagnose whether the sampling circuit of the first battery fails according to the voltage change of the filter capacitor when the equalization circuit is disconnected and when it is turned on. This method avoids the problem in the prior art that an additional backup sampling circuit is required for failure diagnosis, thereby effectively reducing the diagnosis cost and the overall size of the detection circuit.

[0026] The following Figure 2 will introduce in detail the battery pack 200 and the detection circuit 210 provided by the embodiments of the present application. As Figure 2 shown, the battery pack 200 includes a plurality of batteries connected in series (for example, including battery B1, battery B2, and battery B3) and a plurality of detection circuits 210 corresponding to the plurality of batteries one by one. One of the plurality of detection circuits 210 is used to detect the connection circuit of the first battery among the plurality of batteries connected in series. The first battery can be any one of the plurality of batteries in the battery pack 200. For the convenience of description, the following takes the first battery as Figure 2 battery B1 in

[0027] For details, see Figure 2 , the detection circuit 210 includes a self-checking resistor, an equalization circuit, a filtering circuit, and a sampling chip.

[0028] The self-checking resistor can be understood as a resistor with a self-detection function. The self-checking resistor can include a first self-checking resistor R3 connected to the positive electrode of battery B1 and a second self-checking resistor R13 connected to the negative electrode of battery B1. The resistance values of the first self-checking resistor R3 and the second self-checking resistor R13 can be equal.

[0029] The equalization circuit is a circuit commonly provided in a battery pack 200 including a plurality of batteries. This is because the manufacturing levels and processes of the individual batteries in the battery pack 200 may vary slightly, and it is impossible to ensure the consistency of the batteries in the battery pack 200. The capacity individual differences and voltage differences caused by the self-discharge rate during the use of the batteries will result in significant differences in the parameters of the individual batteries in the battery pack 200. In view of this, after corresponding equalization circuits are provided for each battery in the battery pack 200, the equalization circuits can be used to discharge the corresponding batteries, thereby reducing the problem of charge / discharge imbalance between the individual batteries and improving the consistency of the individual batteries in the battery pack 200.

[0030] As Figure 2As shown in the figure, the equalization circuit includes an equalization switch and an equalization resistor. The equalization circuit can be connected in series with the first battery through a self-checking resistor. Specifically, the equalization circuit includes a first equalization resistor R11 and a second equalization resistor R12. Both ends of the equalization switch S3 are connected to the first equalization resistor R11 and the second equalization resistor R12 respectively. The other end of the first equalization resistor R11 is connected to the first self-checking resistor R3, and the other end of the second equalization circuit R12 is connected to the second self-checking resistor R13. When the equalization switch S3 is closed, the equalization circuit is in a conducting state, and the equalization circuit is used to transfer the supply current to discharge the battery B1. When the equalization switch S3 is opened, the equalization circuit is in an open state, and there is no current on the equalization circuit.

[0031] The filtering circuit is connected in parallel with the equalization circuit. Specifically, the filtering circuit includes a filtering capacitor C3, a first filtering resistor R8, and a second filtering resistor R14. The first filtering resistor R8 and the second filtering resistor R14 are respectively connected in series at both ends of the filtering capacitor. The other end of the first filtering resistor R8 is connected to the connection point between the first self-checking resistor R3 and the equalization circuit, and the other end of the second filtering resistor R14 is connected to the connection point between the second self-checking resistor R13 and the equalization circuit.

[0032] The sampling chip is connected to both ends of the filtering capacitor C3 in the filtering circuit. As mentioned above, the battery pack 200 may include multiple detection circuits 210. It should be noted that the sampling chips in each detection circuit 210 are the same sampling chip, that is to say, the same sampling chip can be used by multiple detection circuits 210. In the embodiment of the present application, the sampling chip, the filtering circuit, and the self-checking resistor jointly form the sampling circuit of the first battery, and the embodiment of the present application can utilize the equalization circuit to realize the self-detection of the sampling circuit of the first battery to determine whether the first sampling circuit fails. Specifically, the sampling chip can be used to determine whether the sampling circuit of the first battery fails according to the first voltage and the second voltage. Among them, the first voltage is the voltage on the filtering capacitor C3 when the equalization switch is opened, and the second voltage is the voltage on the filtering capacitor C3 when the equalization switch is closed. Taking the first battery as the battery B1 as an example, the first voltage can be marked as V 1-1 , and the second voltage can be marked as V 1-2 .

[0033] The detection circuit 210 provided by the embodiment of the present application includes the sampling circuit and the equalization circuit of the first battery. By multiplexing the equalization circuit and adding a self-checking resistor in the sampling circuit of the first battery, it is possible to diagnose whether the sampling circuit of the first battery fails according to the voltage change on the filtering capacitor C3 when the equalization circuit is opened and closed. This method avoids the problem in the prior art that an additional backup sampling circuit is required for failure diagnosis, thereby effectively reducing the diagnosis cost and the overall size of the detection circuit 210.

[0034] As described above, the first voltage and the second voltage are the voltages on the filter capacitor when the equalization is off and on, respectively. To obtain these voltages, in some embodiments, the sampling chip is further configured to: control the acquisition of the first voltage on the filter capacitor when the equalization switch is off; control the equalization switch to switch from the off state to the on state, and acquire the second voltage on the filter capacitor.

[0035] Embodiments of the present application do not specifically limit the manner in which the sampling chip determines whether the sampling circuit of the first battery fails according to the first voltage and the second voltage. As an example, the sampling chip is configured to determine whether the sampling circuit of the first battery according to the first voltage and the second voltage specifically includes: determining whether the first voltage and the second voltage satisfy a first preset rule; in response to the first voltage and the second voltage satisfying the first preset rule, determining that the sampling circuit of the first battery is normal; in response to the first voltage and the second voltage not satisfying the first preset rule, determining that the sampling circuit of the first battery fails.

[0036] The first preset rule may be a rule for defining (or judging) whether the sampling circuit of the first battery fails. Embodiments of the present application do not specifically limit the first preset rule, as long as the rule can judge the first voltage and the second voltage to determine whether the sampling circuit of the first battery fails. For example, the first preset rule may be that the absolute value of the difference between the equivalent voltage based on the second voltage and the first voltage is less than a second preset value VTH2. The equivalent voltage based on the second voltage is related to the self-checking resistor and the equalization resistor. For example, the equivalent voltage of the second voltage = the second voltage / (the first equalization resistor + the second equalization resistor) * (the first self-checking resistor + the second self-checking resistor + the first equalization resistor + the second equalization resistor). Taking Figure 2 the sampling circuit of battery B1 in 1-2 ’ = V 1-2 / (R11 + R12) * (R3 + R13 + R11 + R12) as an example. Based on this, the first preset rule may be |V 1-2 ’ - V 1-1 | < VTH2.

[0037] By determining whether the first voltage and the second voltage satisfy the first preset rule, it is possible to detect whether the sampling circuit of the first battery fails, which not only realizes self-detection but also ensures the accuracy of the failure detection of the sampling circuit of the first battery.

[0038] As described above, an equalization circuit is provided in the embodiment of the present application, and the self-detection of whether the sampling circuit of the first battery fails can be realized through the cooperation of the equalization circuit. However, in some cases, the equalization circuit may also fail. For example, the equalization switch in the equalization circuit fails or the equalization circuit is short-circuited. If the equalization circuit fails, a series of problems will also occur. For example, if the equalization switch does not work, it will cause the battery life and capacity to decay. Another example is that if the power switch tube in the equalization switch is broken down and fails, it will cause the battery to be discharged and damaged. Another example is that the failure of the equalization circuit will also cause the self-detection result of whether the sampling circuit of the first battery fails to be abnormal.

[0039] To avoid the above problems, the sampling chip in the embodiment of the present application is further configured to determine whether the equalization circuit fails according to the first voltage and the second voltage before determining whether the sampling circuit of the first battery fails according to the first voltage and the second voltage. The embodiment of the present application does not specifically limit the manner in which the sampling chip determines whether the equalization circuit fails according to the first voltage and the second voltage. For example, it may be determined whether the equalization circuit fails by determining whether the first voltage and the second voltage satisfy a second preset rule. Specifically, the sampling chip is configured to: before determining whether the sampling circuit of the first battery fails according to the first voltage and the second voltage, determine whether the first voltage and the second voltage satisfy a second preset rule; in response to the first voltage and the second voltage satisfying the second preset rule, determine that the equalization circuit is normal; in response to the voltage and the second voltage not satisfying the second preset rule, determine that the equalization circuit fails. In some embodiments, after determining that the equalization circuit is normal, the sampling chip is configured to perform the following operations: determine whether the sampling circuit of the first battery fails according to the first voltage and the second voltage. After determining that the equalization circuit fails, the sampling chip does not perform the following operations: determine whether the sampling circuit of the first battery fails according to the first voltage and the second voltage.

[0040] It should be noted that the second preset rule is different from the first preset rule described above. The second preset rule may be a rule for defining (or judging) whether the equalization circuit fails. The embodiment of the present application does not specifically limit the second preset rule, as long as the rule can judge the first voltage and the second voltage to determine whether the equalization circuit fails. For example, the second preset rule is that the absolute value of the difference between the first voltage and the second voltage is greater than a first preset value VTH1. Taking Figure 2 the sampling circuit of battery B1 in 1-1 as an example, the second preset rule is |V 1-2 −V

[0041] |>VTH1. By determining whether the first voltage and the second voltage satisfy the second preset rule, the detection of whether the equalization circuit fails can be performed, which not only realizes the self-detection of the equalization circuit but also avoids the poor detection accuracy and redundant operations caused by detecting whether the sampling circuit of the first battery fails when the equalization circuit is invalid.

[0042] It should be noted that the present application embodiment does not specifically limit the first preset value VTH1 and the second preset value VTH2, which can be set according to calculations, simulations, or designs.

[0043] As described above, the detection circuits 210 in the battery pack 200 can include multiple ones, and the multiple detection circuits 210 correspond to multiple batteries one by one. Each of the multiple detection circuits 210 has the same structure as the detection circuit 210 described above. The only thing to note is that the sampling chips used in the multiple detection circuits 210 can be the same one. The above mainly takes the battery B1 in the multiple batteries as an example to introduce its detection circuit 210. For the convenience of understanding, the detection circuits 210 corresponding to the battery B2 and the battery B3 will be briefly introduced below.

[0044] The detection circuit 210 corresponding to the battery B2 includes a self-checking resistor (including R2 (i.e., the first self-checking resistor) and R3 (i.e., the second self-checking resistor)), an equalization circuit (including the first equalization resistor R4, the equalization switch S2, and the second equalization resistor R7), a filtering circuit (including the first filtering resistor R6, the filtering capacitor C2, and the second filtering resistor R8), and a sampling chip. The self-checking resistor, the filtering circuit, and the sampling chip together form the sampling circuit of the battery B2. The sampling chip can perform self-detection on the effectiveness of the sampling circuit of the battery B2 and / or the effectiveness of the equalization circuit based on a similar method as described above.

[0045] The detection circuit 210 corresponding to the battery B3 includes a self-checking resistor (including R1 (i.e., the first self-checking resistor) and R2 (i.e., the second self-checking resistor)), an equalization circuit (including the first equalization resistor R9, the equalization switch S1, and the second equalization resistor R10), a filtering circuit (including the first filtering resistor R5, the filtering capacitor C1, and the second filtering resistor R5), and a sampling chip. The self-checking resistor, the filtering circuit, and the sampling chip together form the sampling circuit of the battery B3. The sampling chip can perform self-detection on the effectiveness of the sampling circuit of the battery B3 and / or the effectiveness of the equalization circuit based on a similar method as described above.

[0046] The present application embodiment does not specifically limit the types of the equalization switch S1, the equalization switch S2, or the equalization switch S3. For example, the equalization switch S1, the equalization switch S2, or the equalization switch S3 can be any one of the following switches: metal oxide semiconductor field effect transistor (MOSFET), insulated gate bipolar transistor (IGBT), gate turn-off thyristor (GTO), etc.

[0047] For the convenience of understanding the operations performed by the sampling chip in the present application embodiment, the following will be combined with Figure 3An exemplary explanation is given for the method executed by the sampling chip in the embodiments of the present application. It should be noted that Figure 3 The method in Figure 3 is a schematic flowchart of the sampling chip diagnosing the connection circuit of battery B1 among multiple batteries. For multiple batteries in a battery pack, the method in

[0048] can be repeated for different batteries Figure 3 to diagnose the connection circuits of each battery. See

[0049] The method 300 for the sampling chip to detect (or diagnose) the connection circuit of the first battery includes steps S310 - S390.

[0050] In step S310, start sampling and diagnosing the voltage of the first battery. 1-1 .

[0051] In step S320, the balancing switch of the balancing circuit is in the off state.

[0052] In step S330, close the balancing switch.

[0053] The balancing switches in steps S320 and S330 are the balancing switches corresponding to the first battery. For example, when the first battery is B1, the balancing switch is S3.

[0054] In step S340, collect the second voltage V 1-2 .

[0055] In step S350, perform the judgment: |V 1-1 - V 1-2 | > VTH1.

[0056] If yes, execute step S360.

[0057] If no, execute step S370.

[0058] In step S370, prompt that the balancing circuit fails.

[0059] In step S360, perform the judgment: |V 1-2 / (R11 + R12) * (R3 + R13 + R11 + R12) - V 1-1 | < VTH2.

[0060] If yes, execute step S380.

[0061] In step S380, prompt that both the balancing circuit and the sampling circuit are normal.

[0062] If no, execute step S390.

[0063] In step S390, a prompt indicates that the resampling circuit has failed.

[0064] An embodiment of the present application also provides a battery management system (BMS), which includes the battery pack as described above.

[0065] It should be understood that in various embodiments of the present application, the sequence numbers of the above processes do not imply the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0066] In several embodiments provided by the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections between each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be electrical, mechanical, or other forms.

[0067] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0068] In addition, in each embodiment of the present application, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0069] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website, computer, server, or data center to another website, computer, server, or data center by wire (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be read by a computer or a data storage device such as a server or data center that includes one or more integrated available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a digital video disc (DVD)), or a semiconductor medium (such as a solid state disk (SSD)), etc.

[0070] As described above, the above are only the specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A detection circuit, characterized in that, The detection circuit is used to detect the connection circuit of the first battery among a plurality of batteries connected in series. The detection circuit includes: A self-checking resistor; An equalization circuit including an equalization switch, and the equalization circuit is connected in series with the first battery through the self-checking resistor; A filtering circuit including a filtering capacitor, and the filtering circuit is connected in parallel with the equalization circuit; A sampling chip connected to both ends of the filtering capacitor. The sampling chip, the filtering circuit and the self-checking resistor together form the sampling circuit of the first battery. The sampling chip is used for: Determining whether the sampling circuit of the first battery fails according to a first voltage and a second voltage. The first voltage is the voltage on the filtering capacitor when the equalization switch is off, and the second voltage is the voltage on the filtering capacitor when the equalization switch is on.

2. The detection circuit according to claim 1, wherein The sampling chip is used for: Judging whether the first voltage and the second voltage satisfy a first preset rule; In response to the first voltage and the second voltage satisfying the first preset rule, determining that the sampling circuit of the first battery is normal; In response to the first voltage and the second voltage not satisfying the first preset rule, determining that the sampling circuit of the first battery fails.

3. The detection circuit according to claim 1, wherein The sampling chip is further used for: Before determining whether the sampling circuit of the first battery fails according to the first voltage and the second voltage, determining whether the equalization circuit fails according to the first voltage and the second voltage.

4. The detection circuit according to claim 3, wherein The sampling chip is used for: Before determining whether the sampling circuit of the first battery fails according to the first voltage and the second voltage, judging whether the first voltage and the second voltage satisfy a second preset rule; In response to the first voltage and the second voltage satisfying the second preset rule, determining that the equalization circuit is normal; In response to the voltage and the second voltage not satisfying the second preset rule, determining that the equalization circuit fails.

5. The detection circuit according to claim 4, wherein The second preset rule is that the absolute value of the difference between the first voltage and the second voltage is greater than a first preset value.

6. The detection circuit according to claim 2, wherein The self-checking resistor includes a first self-checking resistor connected to the positive electrode of the first battery and a second self-checking resistor connected to the negative electrode of the first battery. The equalization circuit further includes a first equalization resistor and a second equalization resistor. One end of the first equalization resistor is connected in series with the first self-checking resistor, and the other end of the first equalization resistor is connected in series with one end of the equalization switch. One end of the second equalization resistor is connected in series with the second self-checking resistor, and the other end of the second equalization resistor is connected in series with the other end of the equalization switch. The first preset rule is: |Second voltage / (First equalization resistor + Second equalization resistor) * (First self-checking resistor + Second self-checking resistor + First equalization resistor + Second equalization resistor) - First voltage| < Second preset value.

7. The detection circuit according to claim 1, characterized in that The sampling chip is used for: Controlling to collect the first voltage on the filtering capacitor when the equalization switch is off; Controlling the equalization switch to switch from the off state to the on state and collecting the second voltage on the filtering capacitor.

8. The detection circuit according to claim 6, wherein The filtering circuit further includes a first filtering resistor and a second filtering resistor. One end of the first filtering resistor is connected to one end of the filtering capacitor, the other end of the first filtering resistor is connected to the connection point between the first self-checking resistor and the equalization circuit, one end of the second filtering resistor is connected to the other end of the filtering capacitor, and the other end of the second filtering resistor is connected to the connection point between the second self-checking resistor and the equalization circuit.

9. A battery pack, characterized in that, Comprising a plurality of batteries connected in series and a plurality of detection circuits as claimed in any one of claims 1 to 8 corresponding to the plurality of batteries one by one.

10. A battery management system, characterized in that, Comprising a battery pack as claimed in claim 9.

Images