A battery management system and its control method

Abstract

The present invention discloses a battery management system for managing a battery. The battery includes a plurality of serially connected cells. The battery management system includes a main control unit, an internal resistance detection unit, and a plurality of bridging units. The internal resistance detection unit is respectively connected to the main control unit and the cells. The internal resistance detection unit is configured to control the cells to discharge and detect the internal resistance values of the cells. The plurality of bridging units are provided in one-to-one correspondence with the plurality of cells. Each bridging unit is bridged across the positive and negative electrodes of the corresponding cell. The plurality of bridging units are all electrically connected to the main control unit, so that the main control unit can control the bridging units to be turned on or off. The battery management system provided by the present invention has a simple structure and is easy to implement. It can effectively improve the reliability of the battery and achieve balanced control of the battery. The present invention also discloses a control method for controlling the above-mentioned battery management system.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a battery management system and a control method thereof. Background Art

[0002] For the power supply environment of all important occasions, the industry has clear requirements for uninterrupted power supply. Especially in the subway industry, where there is a large gathering of people and a very high population density, once the power supply is interrupted, it is easy to cause personnel safety accidents and abnormal operation of the entire subway line. Therefore, the power supply system generally adds a storage battery as an important guarantee for uninterrupted power supply. After a power outage or abnormal operation of the power supply equipment, the storage battery can supply power. Existing storage batteries include multiple batteries connected in series, and each battery discharges or charges simultaneously. When one of the batteries is in a faulty state, the entire storage battery cannot be normally charged or discharged; in addition, the internal resistances of each battery are different, resulting in differences in the charging efficiency and discharging efficiency of each battery. Existing storage batteries cannot achieve balanced control of the batteries, and there is a risk of over-discharge or over-charging of the batteries. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: to provide a battery management system and a control method thereof to solve the problems of low reliability of existing storage batteries and inability to achieve balanced control of the batteries.

[0004] To solve the above technical problem, the technical solution adopted by the present invention is: a battery management system for managing a storage battery, the storage battery including multiple batteries connected in series, the battery management system including a main control unit, an internal resistance detection unit, and multiple cross-connection units. The internal resistance detection unit is respectively connected to the main control unit and the battery. The internal resistance detection unit is used to control the battery to discharge and detect the internal resistance value of the battery. The multiple cross-connection units are arranged in one-to-one correspondence with the multiple batteries. The cross-connection unit is cross-connected across the positive and negative electrodes of the corresponding battery. The multiple cross-connection units are all electrically connected to the main control unit, so that the main control unit controls the cross-connection unit to conduct or disconnect.

[0005] Further, the cross-connection unit includes a switch and an MOS transistor. The source electrode of the MOS transistor is connected to the negative electrode of the battery, and the drain electrode of the MOS transistor is connected to the positive electrode of the battery, so that the MOS transistor is cross-connected across the two ends of the battery. The gate electrode of the MOS transistor is connected to the switch, and the switch is connected to the main control unit, so that the main control unit controls the switch to conduct or disconnect.

[0006] Further, the MOS transistor is an N-type MOS transistor.

[0007] Further, it further includes a voltage detection unit and a current detection unit. Both the voltage detection unit and the current detection unit are communicatively connected to the main control unit. The voltage detection unit is used to obtain the voltage of the battery, and the current detection unit is used to obtain the current of the battery.

[0008] Further, the main control unit includes a controller and a plurality of driving modules. The plurality of driving modules are arranged in one-to-one correspondence with the plurality of bridging units. The output end of the driving module is electrically connected to its corresponding bridging unit, and the input end of the driving module is connected to the controller.

[0009] Another object of the present invention is to provide a control method for controlling the above-mentioned battery management system, including the following steps: obtaining the remaining capacity of the battery; when the remaining capacity is greater than the first preset remaining capacity, the battery discharges through the internal resistance detection unit according to the first preset period; when the remaining capacity is less than the second preset remaining capacity, the battery enters a sleep state according to the second preset period.

[0010] Further, when the battery enters a sleep state according to the second preset period, it includes: the bridging unit and the internal resistance detection unit corresponding to the battery stop working.

[0011] Further, when the battery discharges according to the first preset period, it includes: the internal resistance detection unit controls the battery to discharge according to the first preset period.

[0012] Further, it further includes the step: when the battery is in a fault state, the bridging unit corresponding to the battery is turned on.

[0013] Further, when the battery is in a fault state and the bridging unit corresponding to the battery is turned on, it includes: the voltage detection unit obtains the voltage of the battery. When the voltage of the battery is lower than the preset voltage threshold, the bridging unit corresponding to the battery is turned on.

[0014] The beneficial effects of the present invention are as follows: when one of the batteries of the storage battery is in a fault state, the battery management system provided by the present invention can control the bridging unit corresponding to the faulty battery to be turned on, so that a path is formed between the positive and negative electrodes of the battery in the fault state, so as to ensure that the storage battery can discharge and charge through other normal batteries; the battery management system can also control the battery to perform additional discharge through the internal resistance detection unit or control the battery to enter an intermittent sleep state through the bridging unit, so as to increase or decrease the loss of the battery, so that the batteries of the storage battery achieve the effect of balanced control. The battery management system provided by the present invention has a simple structure and is easy to implement. It can effectively improve the reliability of the storage battery and achieve balanced control of the storage battery. Description of the Drawings

[0015] Figure 1 The schematic block diagram of the battery management system according to the present invention in an embodiment;

[0016] Figure 2 The schematic diagram of the bridging unit of the battery management system according to the present invention in an embodiment;

[0017] Figure 3 The flowchart of steps of the control method according to the present invention in an embodiment.

[0018] Label description:

[0019] 1. Main control unit; 11. Controller; 12. Driver module;

[0020] 2. Internal resistance detection unit;

[0021] 3. Bridging unit; 31. Switch; 32. MOS transistor;

[0022] 4. Voltage detection unit;

[0023] 5. Current detection unit;

[0024] 6. Battery; 61. Cell. Specific embodiments

[0025] To describe in detail the technical content, achieved object and effect of the present invention, the following is described in conjunction with embodiments and with reference to the drawings.

[0026] Please refer to Figure 1 and Figure 2 , a battery management system, which is used to manage the battery 6. The battery 6 includes a plurality of serially connected cells 61. The battery management system includes a main control unit 1, an internal resistance detection unit 2 and a plurality of bridging units 3. The internal resistance detection unit 2 is respectively connected to the main control unit 1 and the cell 61. The internal resistance detection unit 2 is used to control the discharge of the cell 61 and detect the internal resistance value of the cell 61. The plurality of bridging units 3 are arranged in one-to-one correspondence with the plurality of cells 61. The bridging unit 3 is bridged across the positive and negative electrodes of the corresponding cell 61. The plurality of bridging units 3 are all electrically connected to the main control unit 1, so that the main control unit 1 controls the bridging unit 3 to conduct or disconnect.

[0027] As can be seen from the above description, the beneficial effects of the present invention are as follows: when one battery 61 of the storage battery 6 is in a fault state, the storage battery management system provided by the present invention can control the conduction of the bridging unit 3 corresponding to the battery in the fault state, so that a path is formed between the positive and negative electrodes of the battery in the fault state, so as to ensure that other batteries in the storage battery 6 can be normally discharged and charged; the storage battery management system can also control the battery 61 to perform additional discharge through the internal resistance detection unit 2 to increase the loss of the battery 61; or control the battery 61 to perform intermittent dormancy through the bridging unit 3 to reduce the loss of the battery 61, so as to achieve the effect of balanced control of each battery 61 of the storage battery 6. The storage battery management system provided by the present invention has a simple structure and is easy to implement. It can effectively improve the reliability of the storage battery 6 and achieve balanced control of the storage battery 6.

[0028] Further, the bridging unit 3 includes a switch 31 and an MOS transistor 32. The source electrode of the MOS transistor 32 is connected to the negative electrode of the battery 61, and the drain electrode of the MOS transistor 32 is connected to the positive electrode of the battery 61, so that the MOS transistor 32 is bridged across both ends of the battery 61. The gate electrode of the MOS transistor 32 is connected to the switch 31, and the switch 31 is connected to the main control unit 1, so that the main control unit 1 controls the switch 31 to conduct or disconnect.

[0029] As can be seen from the above description, the main control unit 1 can control the switch 31 to conduct or disconnect. When the switch 31 conducts, the gate electrode of the MOS transistor 32 is energized to control the conduction and cut-off between the drain electrode and the source electrode of the MOS transistor 32 by controlling the gate voltage of the MOS transistor 32.

[0030] Further, the MOS transistor 32 is an N-type MOS transistor 32.

[0031] Further, it further includes a voltage detection unit 4 and a current detection unit 5. The voltage detection unit 4 and the current detection unit 5 are both communicatively connected to the main control unit 1. The voltage detection unit 4 is used to obtain the voltage of the battery 61, and the current detection unit 5 is used to obtain the current of the battery 61.

[0032] As can be seen from the above description, the storage battery management system obtains the voltage of the battery 61 through the voltage detection unit 4 to monitor the state of the battery 61; the current detection unit 5 obtains the current of the battery 61 to calculate the remaining capacity of the battery 61, and performs balanced control on the battery 61 according to the remaining capacity of the battery 61.

[0033] Further, the main control unit 1 includes a controller 11 and a plurality of driving modules 12. The plurality of driving modules 12 are arranged in one-to-one correspondence with the plurality of bridging units 3. The output end of the driving module 12 is electrically connected to its corresponding bridging unit 3, and the input end of the driving module 12 is connected to the controller 11.

[0034] As can be seen from the above description, the controller 11 can provide a driving voltage to the bridging unit 3 through the driving module 12 to control the conduction and disconnection of the MOS transistor 32 of the bridging unit 3.

[0035] Please refer to Figure 3 , another object of the present invention is to provide a control method for controlling the above-mentioned battery management system, including the following steps: obtaining the remaining capacity of the battery 61; when the remaining capacity is greater than the first preset remaining capacity, the battery 61 discharges through the internal resistance detection unit 2 according to the first preset period; when the remaining capacity is less than the second preset remaining capacity, the battery 61 enters a sleep state according to the second preset period.

[0036] As can be seen from the above description, when the remaining capacity of the battery 61 is high, the battery 61 discharges additionally through the internal resistance detection unit 2 to increase the loss rate of the remaining capacity of the battery 61; when the remaining capacity of the battery 61 is low, the battery 61 enters an intermittent sleep state to reduce the discharge efficiency of the battery 61 and lower the loss rate of the remaining capacity of the battery 61.

[0037] Further, when the battery 61 enters a sleep state according to the second preset period, it includes: the bridging unit 3 and the internal resistance detection unit 2 corresponding to the battery 61 stop working.

[0038] As can be seen from the above description, the bridging unit 3 and the internal resistance detection unit 2 corresponding to the battery 61 stopping working can reduce the discharge efficiency of the battery 61, thereby reducing the loss rate of the remaining capacity of the battery 61.

[0039] Further, when the battery 61 discharges according to the first preset period, it includes: the internal resistance detection unit 2 controls the battery 61 to discharge according to the first preset period.

[0040] As can be seen from the above description, the internal resistance detection unit 2 obtains the internal resistance value of the battery 61 by controlling the discharge of the battery 61. When the remaining capacity of the battery 61 is high, the battery 61 discharges additionally through the internal resistance detection unit 2 according to the first preset period to increase the loss rate of the remaining capacity of the battery 61.

[0041] Further, it further includes the step: when the battery 61 is in a fault state, the bridging unit 3 corresponding to the battery 61 is turned on.

[0042] As can be seen from the above description, when the battery 61 fails, the bridging unit 3 conducts to form a path between the positive and negative electrodes of the battery 61 in the fault state, ensuring that the other batteries 61 of the storage battery 6 can work properly.

[0043] Further, when the battery 61 is in a fault state, the bridging unit 3 corresponding to the battery 61 conducts, including: the voltage detection unit 4 obtains the voltage of the battery 61, and when the voltage of the battery 61 is lower than a preset voltage threshold, the bridging unit 3 corresponding to the battery 61 conducts.

[0044] As can be seen from the above description, when one battery 61 in the storage battery 6 is in a power loss fault state, the bridging unit corresponding to the battery in the power loss state conducts, so that the other normal batteries in the storage battery can form a normal current path and supply power to the load normally.

[0045] Embodiment 1

[0046] As is well known, multiple batteries 61 are usually connected in series in the storage battery 6, and the damage or abnormality of one battery 61 will cause the entire storage battery 6 to be unable to charge and discharge normally. Therefore, how to avoid the impact of a single-point fault of the storage battery 6 on the overall power supply has become an important research topic. The existing storage battery 6 is prone to the following two abnormal phenomena:

[0047] The first abnormal phenomenon is that the internal resistance of the battery 61 will cause self-loss to the battery 61. The internal resistances of the batteries 61 are different. The self-loss of the battery 61 with a large internal resistance is large, and the self-loss of the battery 61 with a small internal resistance is small. Over time, the difference in the remaining capacity between the battery 61 with a large internal consumption and the battery 61 with a small internal consumption will become larger and larger. The battery with a small internal resistance is prone to overcharging, and there is a risk of explosion and fire after a long time.

[0048] The second abnormal phenomenon is that when one battery 61 in the storage battery 6 has a fault such as liquid leakage short circuit or foreign object short circuit, the energy of the battery in the fault state will be emptied in a short time. Since the batteries 61 in the storage battery 6 are connected in series, even if the other batteries in the storage battery 6 have sufficient capacity, the storage battery 6 cannot supply power normally.

[0049] To solve the above problems of the existing storage battery 6, please refer to Figures 1 to 2, an embodiment of the present invention provides a battery management system for managing a battery 6. The battery 6 includes a plurality of serially connected cells 61 to achieve balanced control of the plurality of cells 61 of the battery 6 and improve the power supply reliability of the battery 6. In this embodiment, the battery management system includes a main control unit 1, an internal resistance detection unit 2, and a plurality of bridging units 3. The internal resistance detection unit 2 is respectively connected to the cell 61 and the main control unit 1. The internal resistance detection unit 2 is used to control the discharge of the cell 61 and detect the internal resistance value of the cell 61. The plurality of bridging units 3 are arranged in one-to-one correspondence with the plurality of cells 61. The bridging unit 3 is bridged across the positive and negative terminals of the corresponding cell 61. The plurality of bridging units 3 are all electrically connected to the main control unit 1, so that the main control unit 1 controls the bridging unit 3 to conduct or disconnect.

[0050] In this embodiment, the internal resistance detection unit 2 uses the DC discharge method to calculate the internal resistance of the cell 61, that is, by directly measuring the voltage and current of the cell during discharge to calculate the internal resistance value of the cell 61. Therefore, in this embodiment, the internal resistance detection unit 2 will additionally perform a small current discharge on the cell 61 and simultaneously detect the voltage at the cell port. As an example: Assume that when the internal resistance detection unit 2 does not perform additional discharge on the cell 61, the current of the cell 61 is I1 and the voltage is U1, and when the internal resistance detection unit 2 performs additional discharge on the cell 61, the current of the cell 61 is I2 and the voltage is U2. Then the internal resistance of the cell is R = (U1 - U2) / (I2 - I1). Optionally, the battery management system can use the internal resistance detection unit 2 to detect the internal resistance of the cell 61 according to a period ranging from one week to one month as set.

[0051] The battery management system provided in this embodiment can perform balanced control on the cell 61:

[0052] When the remaining capacity of the cell 61 is large, the battery management system can discharge the cell 61 through the internal resistance detection unit 2 to improve the discharge efficiency of the cell with a large remaining capacity and increase the loss rate of the remaining capacity of the internal resistance detection unit 2, so that the remaining capacity of the cell with a large remaining capacity approaches the average value of the remaining capacities of other cells in the battery 6.

[0053] When the remaining capacity of battery 61 is low, the battery management system can control the bridging unit 3 and the internal resistance detection unit 2 corresponding to this battery 61 to enter the sleep mode, so as to reduce the discharge efficiency of the battery with low remaining capacity and reduce the loss rate of the remaining capacity of the battery with low remaining capacity. The other batteries 61 in battery 6 discharge normally. At this time, the loss rate of the remaining capacity of the battery with low remaining capacity will be smaller than that of the remaining capacity of other batteries; during the charging process, when battery 6 is charged as a whole, the battery with low remaining capacity replenishes more energy, so that the remaining capacity of the battery with low remaining capacity gradually approaches the average value of the remaining capacity of battery 6. Therefore, the battery management system provided in this embodiment can solve the above-mentioned first abnormal phenomenon.

[0054] When a fault such as liquid leakage short circuit or foreign object short circuit occurs in one battery 61 of battery 6, the battery management system can control the bridging unit 3 corresponding to the faulty battery to conduct, so as to short-circuit the faulty battery through the bridging unit 3, thereby ensuring that the other batteries 61 in battery 6 in a normal state can discharge normally, and further ensuring the power supply reliability of this battery 6. Therefore, the battery management system provided in this embodiment can solve the above-mentioned second abnormal phenomenon.

[0055] The battery management system designed in this embodiment has a simple structure, low manufacturing cost, and is easy to implement, and has excellent application prospects.

[0056] Specifically, please refer to Figure 2 , in this embodiment, the bridging unit 3 includes a switch 31 and an MOS transistor 32. The source electrode of the MOS transistor 32 is connected to the negative electrode of the battery 61, and the drain electrode of the MOS transistor 32 is connected to the positive electrode of the battery 61, so that the MOS transistor 32 is bridged across the two ends of the battery 61. The gate electrode of the MOS transistor 32 is connected to the switch 31, and the switch 31 is connected to the main control unit 1, so that the main control unit 1 controls the switch 31 to conduct or disconnect.

[0057] In this embodiment, the conduction or disconnection of the switch 31 is controlled to control the power-on or power-off of the gate electrode of the MOS transistor 32. When there is enough voltage at the gate electrode of the MOS transistor 32, the drain electrode and the source electrode of the MOS transistor 32 will conduct, so that the MOS transistor 32 is bridged across the two ends of the battery. At this time, the positive and negative electrodes of the faulty battery form a current path, ensuring that the other batteries 61 in battery 6 can discharge normally and ensuring the power supply reliability of battery 6.

[0058] In detail, in this embodiment, the above-mentioned MOS transistor 32 can specifically be an N-type MOS transistor 32. The input impedance of the N-type MOS transistor 32 is very high and basically does not need to absorb current. The on-resistance of the N-type MOS transistor 32 is very small. When the N-type MOS transistor 32 conducts, it can short-circuit the battery 61, so that the battery 61 is short-circuited.

[0059] In this embodiment, a voltage detection unit 4 and a current detection unit 5 are further included. Both the voltage detection unit 4 and the current detection unit 5 are communicatively connected to the main control unit 1. The voltage detection unit 4 is used to obtain the voltage of the battery 61, and the current detection unit 5 is used to obtain the current of the battery 61.

[0060] Specifically, in this embodiment, the voltage detection unit 4 is set to obtain the voltage of the battery 61, and the state of the battery 61 is judged according to the voltage of the battery 61. For example, the storage battery 6 includes a plurality of batteries 61 with a rated voltage of 12V. When the voltage detection unit 4 detects that the voltage of a battery 61 is higher than 6V, it can be judged that the battery 61 is in a normal state. At this time, the main control unit 1 can control the switch 31 of the bridging unit 3 corresponding to the battery 61 to be in an off state to ensure that the MOS transistor 32 of the bridging unit 3 corresponding to the battery 61 does not short-circuit the battery 61; when the voltage detection unit 4 detects that the voltage of a battery 61 is lower than 6V, it can be judged that the battery 61 is in a power-loss fault state. At this time, the main control unit 1 can control the switch 31 of the bridging unit 3 corresponding to the battery 61 in the fault state to change from the off state to the on state, so that the MOS transistor 32 short-circuits the battery 61, and a current path is formed through the MOS transistor 32 at both the positive and negative ends of the battery 61 to ensure the overall current path of the storage battery 6.

[0061] In the battery management system provided in this embodiment, a current detection unit 5 is also provided. Through the current detection unit 5, the current of each battery 61 in the storage battery 6 can be obtained, and the remaining capacity of the battery 61 can be calculated according to the current of the battery 61 to realize the function of detecting the remaining capacity of the battery 61.

[0062] As Figure 2 shown, in this embodiment, the main control unit 1 includes a controller 11 and a plurality of drive modules 12. The plurality of drive modules 12 are arranged in one-to-one correspondence with the plurality of bridging units 3. The output end of the drive module 12 is electrically connected to its corresponding bridging unit 3, and the input end of the drive module 12 is connected to the controller 11.

[0063] In this embodiment, the controller 11 can control each drive module 12 respectively to control the drive voltage of the gate of the MOS transistor 32 corresponding to the drive module 12, so as to improve the controllability and reliability of the bridging unit 3.

[0064] Please refer to Figure 3, the above battery management system in this embodiment can be controlled by the following control method, including the following steps: obtaining the remaining capacity of battery 61; when the remaining capacity is greater than the first preset remaining capacity, the battery discharges through the internal resistance detection unit according to the first preset period; when the remaining capacity is less than the second preset remaining capacity, the battery goes into sleep according to the second preset period.

[0065] Specifically, in this embodiment, during the discharge of battery 6, the current detection unit 5 obtains the current of battery 61 to calculate the remaining capacity of battery 61 based on the current. The main control unit 1 can calculate the capacity average value of battery 6 according to the remaining capacities of each battery 61, and set the first preset remaining capacity and the second preset remaining capacity according to the capacity average value. As an example: when the capacity average value of battery 6 is 100AH, the first trigger threshold for triggering the discharge of battery 61 can be set to 5AH, and the first preset remaining capacity of 105AH can be obtained based on the first trigger threshold and the capacity average value; the second trigger threshold for triggering the sleep of battery 61 can be set to 5AH, and the second preset remaining capacity of 95AH can be obtained based on the second trigger threshold and the capacity average value.

[0066] In this embodiment, the battery 61 goes into sleep according to the second preset period, including: the bridging unit 3 and the internal resistance detection unit 2 corresponding to the battery 61 stop working.

[0067] Since separately configuring a charging device for each battery will greatly increase the application cost of battery 6, it is relatively difficult to perform equalization control on the battery with a small remaining capacity. In this embodiment, the battery management system can intermittently control the bridging unit 3 and the drive module 12 corresponding to the battery with a small remaining capacity to go into sleep, so as to reduce the discharge efficiency of the battery with a small remaining capacity, so that the loss rate of the remaining capacity of the battery with a small remaining capacity is less than the loss rate of the remaining capacities of other batteries in battery 6, and during the charging process of battery 6, the battery with a small remaining capacity has a greater supplementary energy compared to other batteries in battery 6. During the application process, the remaining capacities of other batteries in battery 6 will gradually decrease, and the capacity average value of battery 6 will decrease, so that the remaining capacity of the originally battery with a small remaining capacity will gradually tend to the capacity average value of battery 6.

[0068] In this embodiment, the battery 61 discharges according to the first preset period, including: the internal resistance detection unit 2 controls the discharge of the battery 61 according to the first preset period.

[0069] In this embodiment, the battery management system uses the internal resistance detection unit 2 to additionally discharge the battery with a large remaining capacity in the battery 6. As an example: the first preset period can be set to 5 minutes, and the internal resistance detection unit 2 will control the battery with a large remaining capacity to discharge in a cycle every 5 minutes, so that the battery with a large remaining capacity discharges according to the first preset period, thereby increasing the discharge efficiency of the battery with a large remaining capacity and accelerating the loss rate of the remaining capacity of the battery with a large remaining capacity, so that the remaining capacity of the battery with a large remaining capacity gradually decreases to the capacity average value.

[0070] In this embodiment, the above control method further includes the step: when the battery 61 is in a fault state, the bridging unit 3 corresponding to the battery 61 is turned on, so that a path is formed through the bridging unit 3 at both ends of the battery 61.

[0071] This embodiment can prevent the battery 6 from being affected by the single-point failure of the battery 61 in terms of overall charge and discharge. Specifically, the voltage detection unit 4 obtains the voltage of the battery 61. When the voltage of the battery is lower than the preset voltage threshold, it is determined that the battery is in a power loss fault state. At this time, the bridging unit 3 corresponding to the battery in the fault state can be controlled to turn on, so that a path is formed at both the positive and negative ends of the battery in the fault state, thereby ensuring that the paths of other batteries in the battery 6 are not interrupted, so that other batteries in the battery can perform charge and discharge.

[0072] In summary, the battery management system provided by the present invention can control the bridging unit 3 corresponding to the battery in the fault state to turn on when one of the batteries 61 in the battery 6 is in the fault state, so that a path is formed at both the positive and negative ends of the battery in the fault state, thereby ensuring that other batteries in the battery 6 can normally discharge and charge; the battery management system can also control the battery 61 to perform additional discharge through the internal resistance detection unit 2 or control the bridging unit and the internal resistance detection unit corresponding to the battery 61 to intermittently sleep, so as to increase or decrease the loss efficiency of the remaining capacity of the battery 61, so that the effect of balanced control is achieved for each battery 61 of the battery 6. The battery management system provided by the present invention has a simple structure and is easy to implement. It can effectively improve the reliability of the battery 6 and achieve balanced control of the battery 6.

[0073] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent transformations made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in the relevant technical fields, are equally included in the patent protection scope of the present invention.

Claims

1. A control method for a battery management system for managing a battery, the battery comprising a plurality of serially connected cells, characterized in that, The battery management system includes a main control unit, an internal resistance detection unit, and a plurality of bridging units. The internal resistance detection unit is respectively connected to the main control unit and the battery. The internal resistance detection unit is used to control the battery to discharge and detect the internal resistance value of the battery. The plurality of bridging units are arranged in one-to-one correspondence with a plurality of batteries. The bridging unit is bridged across the positive and negative electrodes of the corresponding battery. The plurality of bridging units are all electrically connected to the main control unit, so that the main control unit controls the bridging unit to conduct or disconnect; It further includes a voltage detection unit and a current detection unit. The voltage detection unit and the current detection unit are both communicatively connected to the main control unit. The voltage detection unit is used to obtain the voltage of the battery, and the current detection unit is used to obtain the current of the battery; The control method includes the following steps: During the discharge of the battery, the current detection unit obtains the current of the battery to calculate the remaining capacity of the battery according to the current. The main control unit calculates the capacity average value of the battery according to the remaining capacity of each battery, and sets a first preset remaining capacity and a second preset remaining capacity according to the capacity average value; wherein, the first preset remaining capacity is greater than the second preset remaining capacity; Obtain the remaining capacity of the battery; when the remaining capacity is greater than the first preset remaining capacity, the battery discharges through the internal resistance detection unit according to the first preset period; when the remaining capacity is less than the second preset remaining capacity, the battery goes into sleep according to the second preset period.

2. The control method according to claim 1, characterized in that The bridging unit includes a switch and an MOS transistor. The source electrode of the MOS transistor is connected to the negative electrode of the battery, and the drain electrode of the MOS transistor is connected to the positive electrode of the battery, so that the MOS transistor is bridged across the two ends of the battery. The gate electrode of the MOS transistor is connected to the switch, and the switch is connected to the main control unit, so that the main control unit controls the switch to conduct or disconnect.

3. The control method according to claim 2, wherein The MOS transistor is an N-type MOS transistor.

4. The control method according to claim 1, characterized in that, The main control unit includes a controller and a plurality of driving modules. The plurality of driving modules are arranged in one-to-one correspondence with the plurality of bridging units. The output end of the driving module is electrically connected to the corresponding bridging unit, and the input end of the driving module is connected to the controller.

5. The control method according to claim 1, wherein The battery goes into sleep according to the second preset period, including: the bridging unit and the internal resistance detection unit corresponding to the battery stop working.

6. The control method according to claim 1, wherein The battery discharges according to the first preset period, including: the internal resistance detection unit controls the battery to discharge according to the first preset period.

7. The control method according to claim 1, wherein It further includes the step: when the battery is in a fault state, the bridging unit corresponding to the battery conducts.

8. The control method according to claim 7, wherein When the battery is in a fault state, the bridging unit corresponding to the battery conducts, including: the voltage detection unit obtains the voltage of the battery. When the voltage of the battery is lower than a preset voltage threshold, the bridging unit corresponding to the battery conducts.

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