Detection circuit and battery management system

Abstract

The embodiment of the utility model discloses a detection circuit and a battery management system, the circuit is used for carrying out disconnection detection on at least one battery cell, the circuit comprises at least one detection module, the detection module is provided with at least one first end, the first end is electrically connected with one end of the battery cell, and the first end is electrically connected with the other end of the battery cell; the acquisition module is used for acquiring voltage or current of the battery cell so as to detect the state of the battery cell; the at least one first switch is provided with a second end and a third end, the second end is electrically connected with the first end, and the third end is electrically connected with one end of the battery cell; wherein when the line between one end of the battery cell and the first end is broken, the second end and the third end are conducted, so that under the condition that the sampling line of the battery cell is broken, the first switch can be adopted to ensure that the detection module can normally sample the battery cell, thereby ensuring that the battery cell can be normally used; and the over-charging condition of the battery cell is avoided.

Description

Technical Field

[0001] This application relates to the technical field of batteries, and particularly to a detection circuit and a battery management system. Background Art

[0002] There are often multiple groups of battery cells in a battery pack, and a battery cell combination can be composed of one or more battery cells. In related technologies, the battery pack can use an AFE (Analog Front End) chip through a battery management system to monitor states such as overvoltage, undervoltage, and overcurrent, and perform protection actions when relevant states occur. However, using an AFE chip by the battery management system to monitor the battery cells still has certain limitations. Due to the influence of the installation and use scenarios of the battery pack, the sampling line between the battery cells and the AFE chip may be disconnected, resulting in the AFE chip being unable to timely monitor the states of the battery cells in real time. Summary of the Utility Model

[0003] Aiming at the deficiencies of the prior art, this application provides a detection circuit and a battery management system, aiming to solve the technical problem that the battery cells cannot be sampled in real time in a timely manner after the sampling line is disconnected in the prior art.

[0004] To solve the above problems, in a first aspect, this application provides a detection circuit, which is used to detect disconnection of at least one battery cell. The circuit includes:

[0005] At least one detection module, the detection module is provided with at least one first end, the first end is electrically connected to one end of the battery cell, and is used to collect the voltage or current of the battery cell to detect the state of the battery cell;

[0006] At least one first switch, the first switch is provided with a second end and a third end, the second end is electrically connected to the first end, and the third end is electrically connected to one end of the battery cell;

[0007] Wherein, when there is a disconnection between one end of the battery cell and the first end, the second end and the third end are conducted.

[0008] Further, in the detection circuit, the detection module includes an analog front-end chip and at least one sampling module;

[0009] Wherein, the sampling module is provided with the first end and the third end, the third end is electrically connected to the analog front-end chip, and the second end is electrically connected between the analog front-end and the third end.

[0010] Still further, in the detection circuit, the sampling module includes a first resistor and a first capacitor;

[0011] One end of the first resistor is electrically connected to one end of the battery cell, and the other end of the first resistor is electrically connected to the analog front-end chip. One end of the first capacitor is electrically connected between one end of the first resistor and one end of the battery cell, and the other end of the first capacitor is grounded.

[0012] Further, in the detection circuit, the first switch is further provided with a first control end;

[0013] Wherein, the first control end is electrically connected to the detection module to receive the signal sent by the detection module to control the on / off between the second end and the third end.

[0014] Further, in the detection circuit, a second resistor is provided between the second end and the first end; or / and,

[0015] The second resistor is provided between the third end and one end of the battery cell.

[0016] Further, in the detection circuit, a plurality of the battery cells are connected in series or / and in parallel to form at least one battery cluster or at least one battery pack or at least one battery module;

[0017] Wherein, at least one of the battery clusters or / and at least one of the battery packs or / and at least one of the battery modules corresponds to one detection module one by one, and the battery cells correspond to the first switches one by one.

[0018] Furthermore, in the detection circuit, a plurality of the battery cells are connected in series to form a plurality of the battery packs, and the battery packs correspond to the detection modules one by one.

[0019] Furthermore, in the detection circuit, daisy chain communication is adopted between at least two of the detection modules.

[0020] Further, in the detection circuit, the circuit further includes at least one second switch;

[0021] The second switch is arranged in the loop where the battery cell is located. When a short-circuit fault occurs in the battery cell, the second switch is turned off to cut off the loop of the battery cell.

[0022] Furthermore, in the detection circuit, the circuit further includes at least one third switch;

[0023] Among them, the second switch includes a fourth terminal and a fifth terminal, the third switch includes a sixth terminal and a seventh terminal, the fourth terminal is electrically connected to one end of the battery cell, the fifth terminal is electrically connected to the sixth terminal and one end of an adjacent battery cell of the battery cell respectively, and the seventh terminal is electrically connected to the other end of the battery cell; when a short - circuit fault occurs in the battery cell, the connection between the fourth terminal and the fifth terminal is disconnected, and the connection between the sixth terminal and the seventh terminal is conducted.

[0024] Furthermore, in the detection circuit, at least one of the second switch and the third switch includes a second control terminal;

[0025] Among them, the second control terminal is electrically connected to the detection module, and the detection module controls the on - off of the second switch or / and the third switch by receiving the signal sent by the detection module.

[0026] Further, in the detection circuit, the circuit further includes a main control module, the main control module communicates with the detection module using a daisy - chain communication, the main control module is used for open - circuit diagnosis between one end of the battery cell and the first end, or / and, the main control module is used for short - circuit diagnosis of the battery cell.

[0027] In a second aspect, the present application also provides a battery management system, which includes the detection circuit described in the first aspect.

[0028] The detection circuit provided by the present application is used for open - circuit detection of at least one battery cell. The circuit includes at least one detection module and at least one first switch. The detection module is provided with at least one first end. The first end of the detection module is electrically connected to one end of the battery cell and is used for collecting voltage or current of the battery cell to detect the state of the battery cell; the first switch is provided with a second end and a third end. The second end is electrically connected to the first end of the detection module, and the third end is electrically connected to one end of the battery cell. Furthermore, when there is no open - circuit between one end of the battery cell and the first end, the connection between the second end and the third end of the first switch is in an open state, and when there is an open - circuit between one end of the battery cell and the first end, the connection between the second end and the third end of the first switch is conducted. Thus, in the case of an open - circuit in the sampling line of the battery cell, the first switch can be used to ensure that the detection module can normally sample the battery cell, thereby ensuring that the battery cell can be used normally and avoiding over - charging of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 The first schematic block diagram of the detection circuit provided by the embodiment of the present application;

[0031] Figure 2 The second schematic block diagram of the detection circuit provided by the embodiment of the present application;

[0032] Figure 3 The third schematic block diagram of the detection circuit provided by the embodiment of the present application;

[0033] Figure 4 The circuit diagram of the detection circuit provided by the embodiment of the present application connected to the battery cell;

[0034] Figure 5 The flowchart of the battery cell disconnection detection method provided by the embodiment of the present application. Detailed implementation manners

[0035] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0036] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprise" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0037] It should also be understood that the terms used in this specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in this specification of the present application and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0038] It should be further understood that the term "and / or" used in this specification of the present application and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations. In addition, the terms "first" and "second" are used for descriptive distinction and have no special meaning.

[0039] Please refer to Figure 1 , Figure 1 which is the first schematic block diagram of the detection circuit provided by the embodiment of the present application. As Figure 1 shown, a detection circuit is used for detecting disconnection of at least one battery cell. The circuit includes:

[0040] At least one detection module 100, the detection module 100 is provided with at least one first end, the first end is electrically connected to one end of the battery cell, and is used to collect the voltage or current of the battery cell to detect the state of the battery cell;

[0041] At least one first switch 200, the first switch 200 is provided with a second end and a third end, the second end is electrically connected to the first end, and the third end is electrically connected to one end of the battery cell;

[0042] Wherein, when there is a disconnection between one end of the battery cell and the first end, the second end and the third end are conducted.

[0043] In this embodiment, the number of the first switches 200 can correspond one-to-one to the number of the battery cells, that is, one battery cell corresponds to one first switch 200. At the same time, the detection module 100 is used to collect the current or voltage of at least one battery cell, that is, the detection module 100 can collect the current or voltage of one battery cell, or can also collect the current or voltage of all or part of the battery cells in the battery pack 300 or the battery module.

[0044] Specifically, the first switch 200 in the present application is electrically connected to the detection module 100 and the battery cell respectively. It is equivalent to a backup line for the detection module 100 to collect the current or voltage of the battery cell. Only when the sampling line between the detection module 100 and the first switch 200 is disconnected, the first switch 200 is in the conducting state, so as to ensure that the detection module 100 can continuously collect the current or voltage of the battery cell, and thus ensure the normal use of the battery cell. At the same time, when the sampling line between the detection module 100 and the first switch 200 is not disconnected, the first switch 200 is in the cut-off state, and the detection module 100 can directly collect the current or voltage through the sampling line between it and the battery cell.

[0045] The detection circuit provided by the present application is used to detect open circuits of at least one battery cell. The circuit includes at least one detection module 100 and at least one first switch 200. The detection module 100 is provided with at least one first end. The first end of the detection module 100 is electrically connected to one end of the battery cell and is used to collect the voltage or current of the battery cell to detect the state of the battery cell. The first switch 200 is provided with a second end and a third end. The second end is electrically connected to the first end of the detection module 100, and the third end is electrically connected to one end of the battery cell. Furthermore, when there is no open circuit between one end of the battery cell and the first end, the second end and the third end of the first switch 200 are in an open state, and when there is an open circuit between one end of the battery cell and the first end, the second end and the third end of the first switch 200 are conducting. Thus, when an open circuit occurs in the sampling line of the battery cell, the first switch 200 can be used to ensure that the detection module 100 can normally sample the battery cell, thereby ensuring that the battery cell can be used normally and avoiding overcharging of the battery cell.

[0046] Please continue to refer to Figure 1 , in some embodiments, such as Figure 1 shown, the detection module 100 includes an analog front-end chip AFE and at least one sampling module 110. Among them, the sampling module 110 is provided with a first end and a third end. The third end is electrically connected to the analog front-end chip AFE, and the second end is electrically connected between the analog front-end and the third end.

[0047] In this embodiment, one first end of the detection module 100 can be used as one end of the sampling module 110, which can be electrically connected to one end of the battery cell. The other end of the sampling module 110 can be directly electrically connected to a pin of the analog front-end chip AFE. Thus, the sampling module 110 can sample the current or voltage of the battery cell. After the sampling module 110 samples the current or voltage of the battery cell, it can be input into the analog front-end chip AFE, and the analog front-end chip AFE can thereby know the current state of the battery cell.

[0048] Furthermore, in some embodiments, the sampling module 110 can be an RC sampling module 110, and the RC sampling module 110 is arranged on the sampling line between the battery cell and the detection module 100. Specifically, as Figure 1 shown, the sampling module 110 includes a first resistor and a first capacitor. Among them, one end of the first resistor is electrically connected to one end of the battery cell, the other end of the first resistor is electrically connected to the analog front-end chip AFE, one end of the first capacitor is electrically connected between one end of the first resistor and one end of the battery cell, and the other end of the first capacitor is grounded to GND.

[0049] In some embodiments, the first switch 200 is further provided with a first control end. Among them, the first control end is electrically connected to the detection module 100 to receive a signal sent by the detection module 100 to control the on / off between the second end and the third end.

[0050] In this embodiment, the on / off control of the first switch 200 can be controlled by the detection module 100. Furthermore, the detection module 100 can be electrically connected to the first control end of the first switch 200. Thus, when the sampling line between the detection module 100 and the battery cell is not broken, the detection module 100 can control the first switch 200 to turn off; when the sampling line between the detection module 100 and the battery cell is broken, the detection module 100 can control the first switch 200 to turn on.

[0051] It can be understood that the on / off of the first switch 200 of the present application can also be controlled by the main control module in the battery management system, which is not limited to the control by the detection module 100 mentioned above. The on / off control method of the first switch 200 can be selected according to actual applications, and the present application does not make specific limitations.

[0052] Furthermore, in some embodiments, a second resistor is provided between the second end and the first end; and / or, a second resistor is provided between the third end and one end of the battery cell.

[0053] Specifically, in order to ensure that after the sampling line between the battery cell and the detection module 100 is broken, the detection module 100 can continue to sample the current or voltage of the battery cell, the present application also needs to set a second resistor on the line where the first switch 200 is located. Among them, the second resistor can be provided between the first switch 200 and the battery cell, and at the same time, the second switch can also be provided between the first switch 200 and the detection module 100. Its specific setting method can be selected according to actual applications, and the present application does not make specific limitations.

[0054] Specifically, as Figure 1 shown, the second resistor can be provided between the first switch 200 and the battery cell. At the same time, the first switch 200 can be a MOS transistor. The source and drain of the MOS transistor (i.e., the second end and the third end) are electrically connected to the first end of the detection module 100 and one end of the second resistor respectively, and the gate of the MOS transistor (i.e., the first control end) is electrically connected to a pin of the detection module 100.

[0055] It should be noted that the first switch 200 can also be a switch device such as a triode or a relay. The selection type of the first switch 200 can be selected according to actual applications, and the present application does not make specific limitations.

[0056] In some embodiments, multiple battery cells are connected in series and / or in parallel to form at least one battery cluster or at least one battery pack 300 or at least one battery module; among them, at least one battery cluster and / or at least one battery pack 300 and / or at least one battery module correspond to one detection module 100 one by one, and the battery cells correspond to the first switch 200 one by one.

[0057] In this embodiment, a detection module 100 may correspond to a battery cluster, or a detection module 100 may correspond to a battery pack 300, or a detection module 100 may correspond to a battery module. At the same time, each battery cell in the battery cluster, battery pack 300 or battery module corresponds to a first switch 200. Thus, when the sampling line of any battery cell in the battery cluster, battery pack 300 or battery module is broken, it can be ensured that the detection module 100 can normally sample the broken battery cell.

[0058] In some embodiments, multiple battery cells are connected in series to form multiple battery packs 300, and the battery packs 300 correspond to the detection modules 100 one by one.

[0059] In this embodiment, the detection module 100 is used to sample the current or voltage of the battery cells in the battery pack 300 and detect the state of the battery cells in the battery pack 300. Specifically, each battery cell in the battery pack 300 may be electrically connected to a sampling module 110 in the detection module 100, and the sampling modules 110 corresponding to the battery pack 300 are all electrically connected to a new analog front-end chip.

[0060] Exemplarily, a detection module 100 is electrically connected to a battery pack 300, which can be referred to Figure 1 . As Figure 1 shown, battery cells B1, B2, B3 and B4 may be connected in series to form a battery pack 300. The detection module 100 includes four sampling modules 110 and an analog front-end chip AFE. The first resistors in the sampling modules 110 may be resistor R11, resistor R12, resistor R13 and resistor R14 respectively. The first capacitors in the sampling modules 110 may be capacitor C11, capacitor C12, capacitor C13 and capacitor C14 respectively. The analog front-end chip AFE includes pins VB1, VB2, VB3, VB4, pins CB11, CB12, CB13 and CB14. The first switches 200 may be MOS transistors Q11, MOS transistor Q12, MOS transistor Q13 and MOS transistor Q14 respectively. The second resistors may be resistor R21, resistor R22, resistor R23 and resistor R24 respectively.

[0061] Specifically, one end of the resistor R11 is electrically connected to one end of the capacitor C11 and the positive electrode of the battery cell B1 respectively, the other end of the resistor R11 is electrically connected to the pin VB1, one end of the capacitor C11 is grounded to GND, the drain of the MOS transistor Q11 is electrically connected to the positive electrode of the battery cell B1, the source of the MOS transistor Q11 is electrically connected to the pin VB1, and the gate of the MOS transistor Q11 is electrically connected to the pin CB11. Among them, regarding the resistors R12, R13, and R14 in the sampling module 110, the capacitors C12, C13, and C14 in the sampling module 110, the pins VB2, VB3, VB4, CB12, CB13, and CB14, the MOS transistors Q12, Q13, and Q14, and the resistors R22, R23, and R24, their connection methods can refer to the resistor R11, capacitor C11, pin VB1, pin CB11, and MOS transistor Q11 for connection, and will not be elaborated in detail here.

[0062] In some embodiments, as Figure 4 shown, daisy-chain communication is adopted between at least two detection modules 100. Specifically, the detection circuit of the present application includes a plurality of detection modules 100 and a plurality of first switches 200. Each detection module 100 corresponds to a battery pack 300. Daisy-chain communication can be adopted between at least two detection modules 100, so that all battery cells in the energy storage system can share one service, and at the same time, the wiring cost of the energy storage system can be reduced.

[0063] In some embodiments, as Figure 2 shown, the detection circuit further includes at least one second switch; the second switch is arranged in the loop where the battery cell is located. When a short-circuit fault occurs in the battery cell, the second switch is disconnected to cut off the loop of the battery cell.

[0064] In this embodiment, the detection circuit can also detect whether a short circuit occurs in the battery cell. When the detection circuit detects that a short circuit occurs in the battery cell, in order to avoid thermal runaway of the battery cell, the present application can also set a second switch at the loop of the battery cell, so that when a short-circuit fault occurs in the battery cell, the second switch can be used to cut off the loop where the battery cell is located.

[0065] Specifically, the second switch can be arranged between two adjacent battery cells, such as between the battery cell B1 and the battery cell B2, between the battery cell B2 and the battery cell B3, between the battery cell B3 and the battery cell B4, and between the battery cell B4 and the ground wire.

[0066] Furthermore, in some embodiments, as Figure 3As shown, the detection circuit further includes at least one third switch; wherein, the second switch includes a fourth terminal and a fifth terminal, the third switch includes a sixth terminal and a seventh terminal, the fourth terminal is electrically connected to one end of the battery cell, the fifth terminal is respectively electrically connected to the sixth terminal and one end of an adjacent battery cell of the battery cell, and the seventh terminal is electrically connected to the other end of the battery cell; when a short - circuit fault occurs in the battery cell, the connection between the fourth terminal and the fifth terminal is disconnected, and the connection between the sixth terminal and the seventh terminal is conducted.

[0067] In this embodiment, on the basis of providing the second switch for the battery cell, a third switch can also be provided at both ends of the battery cell. Then, when a short - circuit occurs in the battery cell, the circuit of the battery cell can be cut off in time, and at the same time, the third switch is conducted, so as to ensure that the energy storage system where the battery cell is located can be used normally, that is, when the energy storage system is used normally in this state, the short - circuited battery cell can be avoided.

[0068] In some embodiments, at least one of the second switch and the third switch includes a second control terminal; wherein, the second control terminal is electrically connected to the detection module 100, and the detection module 100 controls the on - off of the second switch or / and the third switch by receiving the signal sent by the detection module 100.

[0069] In this embodiment, the on - off control of the second switch and the on - off control of the third switch can both be controlled by the detection module 100. Then, the detection module 100 can be electrically connected to the control terminal of the second switch and the control terminal of the third switch respectively. Thus, when no short - circuit occurs in the battery cell, the detection module 100 can control the second switch to be conducted and control the third switch to be disconnected, and the energy storage system is used normally; when a short - circuit occurs in the battery cell, the detection module 100 can control the second switch to be disconnected and control the third switch to be conducted, so as to ensure that the energy storage system can still be used normally.

[0070] It can be understood that the on - off of the second switch and the third switch of the present application can also be controlled by the main control module in the battery management system, which is not limited to being controlled by the detection module 100 mentioned above. The on - off control mode of the second switch and the third switch can be selected according to actual applications, and the present application does not make specific limitations.

[0071] Exemplarily, such as Figure 3As shown, the battery cells B1, B2, B3, and B4 can be connected in series to form a battery pack 300. The detection module 100 includes four sampling modules 110 and an analog front-end chip AFE. The first resistors in the sampling modules 110 can be resistor R11, resistor R12, resistor R13, and resistor R14 respectively. The first capacitors in the sampling modules 110 can be capacitor C11, capacitor C12, capacitor C13, and capacitor C14 respectively. The analog front-end chip AFE includes pins VB1, VB2, VB3, VB4, pins CB11, CB12, CB13, CB14, pins CB21, CB22, CB23, CB24, pins CB31, CB32, CB33, CB44, and pin VB0. The first switches 200 can be MOS transistors Q11, MOS transistor Q12, MOS transistor Q13, and MOS transistor Q14 respectively. The second resistors can be resistor R21, resistor R22, resistor R23, and resistor R24 respectively. The second switches can be triodes Q21, triode Q22, triode Q23, and triode Q24 respectively. The third switches can be triodes Q31, triode Q32, triode Q33, and triode Q34 respectively. A capacitor C21 is provided between pin VB1 and pin VB2, a capacitor C22 is provided between pin VB2 and pin VB3, a capacitor C23 is provided between pin VB3 and pin VB4, and a capacitor C24 is provided between pin VB4 and pin VB0.

[0072] Specifically, one end of resistor R11 is electrically connected to one end of capacitor C11 and the positive electrode of battery cell B1 respectively. The other end of resistor R11 is electrically connected to pin VB1. One end of capacitor C11 is grounded to GND. The drain of MOS transistor Q11 is electrically connected to the positive electrode of battery cell B1. The source of MOS transistor Q11 is electrically connected to pin VB1. The gate of MOS transistor Q11 is electrically connected to pin CB11. The emitter of triode Q21 is electrically connected to the negative electrode of battery cell B1 respectively. The collector of triode Q21 is electrically connected to the positive electrode of battery cell B2 and the emitter of triode Q31 respectively. The base of triode Q21 is electrically connected to pin CB12. The collector of triode Q31 is electrically connected to the positive electrode of battery cell B1. The base of triode Q31 is electrically connected to pin CB31. Pin VB0 is sequentially electrically connected to the negative electrode of battery cell B4 through resistor R3 and triode Q24. The negative electrode of battery cell B4 is sequentially grounded to GND through triode Q24 and capacitor C3. Among them, for triodes Q22, Q23, Q24, Q32, Q33, and Q34, they can be set with reference to triodes Q21 and Q31, and will not be elaborated in detail here.

[0073] In some embodiments, such as Figure 4As shown, the detection circuit further includes a main control module, which communicates with the detection module 100 through daisy chain communication. The main control module is used for diagnosing the disconnection between one end of the battery cell and the first end, and / or, the main control module is used for diagnosing the short circuit of the battery cell.

[0074] In this embodiment, the main control module can be an MCU (Microcontroller Unit) chip in the battery management system, and it can communicate with the detection module 100 through daisy chain. After the detection module 100 transmits the information collected from the battery cell to the main control module, the main control module can then analyze whether the battery cell has a disconnection or a short circuit based on this.

[0075] Specifically, as Figure 5 shown, when the main control module detects whether the battery cell has a short circuit or a disconnection, it can specifically adopt the following steps S110 - S140.

[0076] S110. Obtain the current voltage of the battery cell; wherein, the energy storage object where the battery cell is located includes any one of a battery cluster, a battery pack 300, and a battery module;

[0077] S120. If the current voltage of the battery cell is lower than a preset first voltage, obtain the position information of the battery cell in the energy storage object;

[0078] S130. If the position information indicates that the battery cell is not at the first end of each battery cell in the energy storage object, determine that the battery cell is in a short - circuit state;

[0079] S140. If the position information indicates that the battery cell is at the head or tail end of the energy storage object, determine that the sampling line of the battery cell is in a disconnected state.

[0080] Specifically, the current voltage of the battery cell can be collected through the detection circuit in the battery management system. The energy storage object is an object including at least one battery cell, and the energy storage object can be any one of a battery cluster, a battery pack 300, and a battery module. An energy storage system includes at least one energy storage object.

[0081] Meanwhile, when the present application detects a broken wire of a battery cell, a preset first voltage is set according to the battery cell. The first voltage is the critical voltage for whether the battery cell will have a broken wire. After the detection circuit in the battery management system collects the current voltage of the battery cell, by judging whether the current voltage of the battery cell is lower than the first voltage, if it is lower than the first voltage, it can be determined that the battery cell is abnormal. At this time, it cannot be completely determined that the battery cell has a broken wire, and it may also be short-circuited. Therefore, it is also necessary to obtain the position information of the battery cell in its energy storage system, that is, whether the battery cell is at the head or tail end of the connection of each battery cell in its battery cluster, or whether it is at the head or tail end of the connection of each battery cell in the battery pack 300, or whether it is at the head or tail end of the connection of each battery cell in the battery module. When it is determined that the battery cell is at the head or tail end, it can be clearly determined that the battery cell is in a broken wire state. When it is determined that the battery cell is not at the head or tail end of the connection of each battery cell in the corresponding energy storage object, it can be determined that the battery cell is in a short-circuit state.

[0082] Among them, the position information of the battery cell in the energy storage system can be pre-stored in the battery management system of the energy storage system. Then, when the position information of the battery cell is needed, the position information can be directly parsed to obtain the position of the battery cell in the energy storage system. Then, it can be determined whether the battery cell is at the head or tail end of the connection of each battery cell in the corresponding energy storage object, and then it can be accurately determined whether the battery cell has a broken wire or a short circuit.

[0083] It should be noted that the head or tail end mentioned in the present application refers to the last battery cell arranged in sequence after multiple battery cells are connected in series, which can represent that the battery cell is at the head or tail end of the connection of each battery cell in the corresponding energy storage object.

[0084] The battery cell broken wire detection method provided by the present application obtains the current voltage of the battery cell, and then judges whether the current voltage of the battery cell is lower than the preset first voltage. If it is lower than the preset first voltage, there may be a short circuit of the battery cell. To avoid misjudgment, it is also necessary to further obtain the position of the battery cell in its energy storage system, that is, the position information. If the position information shows that the battery cell is not at the head or tail end of the connection of each battery cell in the battery cluster, battery pack 300, or battery module where the battery cell is located, it is determined that the battery cell is in a short-circuit state; if the position information shows that the battery cell is at the head or tail end of the connection of each battery cell in the battery cluster, battery pack 300, or battery module where the battery cell is located, it is determined that the sampling line of the battery cell is in a broken wire state, thereby greatly improving the accuracy of the battery management system for detecting the broken wire of the battery cell and enhancing the safety of the energy storage system.

[0085] In some embodiments, the battery cell broken wire detection method provided by the present application further includes the following steps:

[0086] Obtain the current voltage of the adjacent battery cell of the battery cell;

[0087] If the voltage difference between the current voltage of an adjacent battery cell and the current voltage of the battery cell exceeds a preset voltage, it is determined that the battery cell is in a disconnection state.

[0088] In this embodiment, when the present application detects the disconnection of a battery cell, the battery cell is usually connected in series or in parallel with other battery cells. At the same time, after excessive discharge of the battery cell, the voltage of the battery cell may be lower than a preset first voltage. Therefore, the voltage collected by the battery management system may also be lower than the preset first voltage. When the battery cell is at the head and tail ends of the connections of the battery cells in the corresponding energy storage object and the current voltage is lower than the preset first voltage, if it is directly determined that the battery cell is disconnected, there will also be a misjudgment situation. Therefore, after the current voltage of the battery cell is lower than the preset first voltage, the present application also needs to obtain the current voltage of the adjacent battery cell of the battery cell, and determine whether the battery cell is in a disconnection state by judging whether the voltage difference between the current voltage of the battery cell and the current voltage of its adjacent battery cell exceeds the preset voltage, that is, whether there is a situation of one being low and the other being high. If there is a situation of one being low and the other being high, it can be determined that the battery cell is in a disconnection state; if there is no situation of one being low and the other being high, it is necessary to judge whether the battery cell is at the head and tail ends of the connections of the battery cells in the corresponding energy storage object for further determination.

[0089] It should be noted that when the present application judges whether there is a situation of one being high and the other being low between the current voltage of the battery cell and the current voltage of its adjacent battery cell, it specifically refers to not exceeding the preset voltage. The preset voltage can be 0, or a value such as 0.001V, etc., and can be specifically selected according to actual applications. The present application does not make specific limitations.

[0090] In some embodiments, if the position information is that the battery cell is at the head and tail ends of the connections of the battery cells in the energy storage object, determining that the battery cell is in a disconnection state includes the following steps:

[0091] If the position information is that the battery cell is at the head and tail ends of the connections of the battery cells in the energy storage object, obtain the current total voltage of the energy storage object;

[0092] If the current total voltage is not lower than a preset second voltage, it is determined that the sampling line of the battery cell is in a disconnection state.

[0093] In this embodiment, since the voltage collected by the battery management system may also be lower than the preset first voltage when the battery cell is in a short - circuit state. Therefore, when it is judged that the collected voltage is lower than the preset first voltage, if it is directly determined that the battery cell is in a disconnection state, there will still be a misjudgment situation. To avoid this situation, the present application can also, when determining that the battery cell is at the head and tail ends of the connections of the battery cells in the corresponding energy storage object, determine whether the battery cell is in a disconnection state by obtaining the current total voltage of the energy storage object where the battery cell is located and judging whether the current total voltage is less than the preset second voltage.

[0094] It should be noted that the present application can also further determine whether the battery cell is in a disconnected state by directly judging the current total voltage of the energy storage system, which can be selected according to actual applications and is not specifically limited in the present application.

[0095] In some embodiments, after obtaining the current total voltage of the energy storage object, the method further includes the step of: if the current total voltage is lower than the second voltage, determining that the battery cell is in a short-circuit state.

[0096] In this embodiment, when the battery cell is in a disconnected state, the current total voltage of the energy storage object actually does not change. Only when it is short-circuited, the current total voltage of the energy storage object will be lower than the preset second voltage. Therefore, when the current total voltage of the energy storage object is lower than the preset second voltage, it can be determined that the battery cell is in a short-circuit state; when the current total voltage of the energy storage object is not lower than the preset second voltage, it can be determined that the battery cell is in a disconnected state.

[0097] In some embodiments, after obtaining the current voltage of the battery cell, the method further includes the step of: if the current voltage of the battery cell is not lower than the first voltage, determining that the sampling line of the battery cell is in a normal state.

[0098] Specifically, when the current voltage of the battery cell is not lower than the preset first voltage, it can be determined that the battery cell is neither in a disconnected state nor in a short-circuit state, and thus it can be clearly determined that the sampling of the battery cell by the detection circuit is in a normal sampling state.

[0099] In some embodiments, after determining that the sampling line of the battery cell is in a disconnected state, the method further includes the step of: controlling a preset first switch 200 to conduct to realize normal sampling of the battery cell; wherein, the first switch 200 is located on the standby sampling line, and the standby sampling line is connected in parallel with the sampling line of the battery cell.

[0100] In this embodiment, when the present application detects the disconnection of the battery cell, it specifically uses the detection circuit in the battery management system to implement. This detection circuit also has the function of collecting current or voltage of the battery cell. In order to avoid the situation that the detection circuit cannot continue to collect current or voltage of the battery cell after detecting the disconnection of the battery cell, the present application can also set a first switch 200 in the detection circuit. Then, after determining the disconnection of the battery cell, the preset first switch 200 can be controlled to conduct to realize normal sampling of the battery cell, thereby ensuring the normal operation of the battery management system.

[0101] In some embodiments, after determining that the battery cell is in a short-circuit state, the method further includes the step of: controlling a preset second switch to disconnect to disconnect the loop of the battery cell; wherein, the second switch is arranged on the loop that conducts the battery cell.

[0102] In this embodiment, when the present application detects a broken wire of the battery cell, it is specifically implemented by using a detection circuit in the battery management system. This detection circuit also has the function of collecting current or voltage of the battery cell. When a short circuit of the battery cell occurs during the detection of the broken wire of the battery cell, in order to ensure the safety of the battery cell and avoid thermal runaway, the present application can also set a second switch in the detection circuit. Furthermore, after determining the short circuit of the battery cell, the preset second switch can be controlled to disconnect, so as to ensure the safety of the battery cell and avoid thermal runaway of the battery cell.

[0103] Further, in some embodiments, after controlling the preset second switch to disconnect to break the circuit of the battery cell, the following steps are further included: controlling the preset third switch to conduct to conduct the circuit of the energy storage object; wherein, both ends of the third switch are electrically connected to both ends of the battery cell.

[0104] In this embodiment, when the present application detects a broken wire of the battery cell, it is specifically implemented by using a detection circuit in the battery management system. This detection circuit also has the function of collecting current or voltage of the battery cell. When a short circuit of the battery cell occurs during the detection of the broken wire of the battery cell, in order to ensure the safety of the battery cell and avoid thermal runaway, and at the same time to ensure the normal use of the energy storage system, the present application can further set a third switch in the detection circuit. Furthermore, after determining the short circuit of the battery cell, the preset second switch can be controlled to disconnect and the third switch can be controlled to conduct, so as to ensure the normal use of the energy storage system while avoiding thermal runaway of the battery cell.

[0105] In some embodiments, the present application also provides a battery management system, which includes the above-mentioned detection circuit.

[0106] The above is only the specific implementation manner 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 various equivalent modifications or substitutions, and these modifications or substitutions should be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A detection circuit, characterized in that: Used to detect disconnection of at least one battery cell, the circuit comprises: At least one detection module, wherein the detection module is provided with at least one first end, the first end is electrically connected to one end of the battery cell and is used to collect voltage or current of the battery cell to detect the state of the battery cell; at least one first switch, wherein the first switch is provided with a second end and a third end, the second end is electrically connected to the first end, and the third end is electrically connected to one end of the battery cell; When the connection between one end of the battery cell and the first end is disconnected, the connection between the second end and the third end is connected.

2. The detection circuit according to claim 1, characterized in that: The detection module includes an analog front-end chip and at least one sampling module; The sampling module is provided with the first end and the third end, the third end is electrically connected to the analog front-end chip, and the second end is electrically connected between the analog front-end and the third end.

3. The detection circuit according to claim 2, characterized in that: The sampling module includes a first resistor and a first capacitor; Among them, one end of the first resistor is electrically connected to one end of the battery cell, the other end of the first resistor is electrically connected to the analog front-end chip, one end of the first capacitor is electrically connected between one end of the first resistor and one end of the battery cell, and the other end of the first capacitor is grounded.

4. The detection circuit according to claim 1, characterized in that: The first switch is also provided with a first control terminal; The first control end is electrically connected to the detection module to receive a signal sent by the detection module to control the connection between the second end and the third end.

5. The detection circuit according to claim 1, characterized in that: A second resistor is provided between the second end and the first end; or / and, The second resistor is arranged between the third end and one end of the battery cell.

6. The detection circuit according to claim 1, characterized in that: A plurality of the battery cells are connected in series or / and in parallel to form at least one battery cluster or at least one battery pack or at least one battery module; Therein, at least one of the battery clusters or / and at least one of the battery packs or / and at least one of the battery modules corresponds one-to-one to one of the detection modules, and the battery cells correspond one-to-one to the first switches.

7. The detection circuit according to claim 6, characterized in that: A plurality of the battery cells are connected in series to form a plurality of the battery packs, and the battery packs correspond to the detection modules one by one.

8. The detection circuit according to claim 6, characterized in that: At least two of the detection modules communicate with each other in a daisy chain.

9. The detection circuit according to any one of claims 1 to 8, characterized in that: The circuit further comprises at least one second switch; The second switch is arranged in the circuit where the battery cell is located. When a short circuit fault occurs in the battery cell, the second switch is disconnected to cut off the circuit of the battery cell.

10. The detection circuit according to claim 9, characterized in that: The circuit further comprises at least one third switch; Among them, the second switch includes a fourth end and a fifth end, the third switch includes a sixth end and a seventh end, the fourth end is electrically connected to one end of the battery cell, the fifth end is respectively electrically connected to the sixth end and one end of an adjacent battery cell of the battery cell, and the seventh end is electrically connected to the other end of the battery cell; when a short circuit fault occurs in the battery cell, the fourth end is disconnected from the fifth end, and the sixth end is connected to the seventh end.

11. The detection circuit according to claim 10, characterized in that: At least one of the second switch and the third switch includes a second control terminal; The second control end is electrically connected to the detection module, and the detection module receives a signal sent by the detection module to control the on and off of the second switch and / or the third switch.

12. The detection circuit according to any one of claims 1 to 8, characterized in that: The circuit also includes a main control module, and daisy chain communication is adopted between the main control module and the detection module. The main control module is used for disconnection diagnosis between one end of the battery cell and the first end, or / and, the main control module is used for short circuit diagnosis of the battery cell.

13. A battery management system, characterized in that: The detection circuit comprises any one of claims 1 to 12.

Images