A battery system with automatic charge and discharge balancing

Abstract

The application discloses a battery system with automatic charge-discharge balance, comprising a plurality of single batteries and control units, the single batteries are connected with the control units one by one, and the control units are connected through CAN bus; the control unit sends its ID signal to the system, receives the ID signal sent by other control units in the system, and establishes communication with each control unit in the system; the control unit obtains the voltage of the single battery corresponding to itself, periodically sends the voltage information of the single battery to the system, and listens to the voltage of the single battery sent by other control units in the system; the control unit obtains the charge-discharge state of the system based on the charge-discharge state of the single battery corresponding to itself, and adjusts the switch state of the discharge MOS tube and the charge MOS tube of the single battery corresponding to itself based on the voltage of the single battery corresponding to itself and the voltage of other single batteries in the system. The application reduces the difference between the actual endurance mileage and the theoretical endurance mileage of the vehicle.

Description

Technical Field

[0001] The present application relates to the field of battery control technology, and in particular to a battery system with automatic charge and discharge balancing. Background Art

[0002] As lithium batteries become increasingly common in automobiles and electric vehicles, the battery life and discharge current of a single battery pack can no longer meet the needs of some vehicle models. When batteries are required to have long battery life and large discharge current, the current main method to increase the battery life and discharge current of the battery system is to directly increase the number of single cells in series or increase the number of battery packs in parallel.

[0003] In a traditional battery system, each single cell is connected to a corresponding charging MOS tube and a discharging MOS tube. When charging the vehicle battery, the charging MOS tubes corresponding to each single cell are turned on and the discharging MOS tubes are turned off, so that the charging current of each single cell flows into the charging MOS tube and the discharging MOS tube through the body diodes of the charging MOS tube and the discharging MOS tube, and the charging operation is performed. When the vehicle battery needs to be discharged, the charging MOS tubes corresponding to each single cell are turned off and the discharging MOS tubes are turned on, so that the discharge current of each single cell flows out through the body diode of the charging MOS tube and the discharging MOS tube, and the discharge operation is performed.

[0004] However, as the number of single cells in the battery system increases, the performance of each single cell will vary during use. In the traditional battery system, the control of charging and discharging of each single cell may result in some single cells not being fully charged during charging, and some single cells being overcharged; or some single cells not being fully discharged during discharging, and some single cells being fully discharged. These situations will cause a large gap between the actual cruising range and the theoretical cruising range of the vehicle during use. Summary of the Invention

[0005] In order to reduce the gap between the actual cruising range and the theoretical cruising range of a vehicle, the present application provides a battery system with automatic charge and discharge balancing.

[0006] In a first aspect, the present application provides a battery system with automatic charge and discharge balancing, which adopts the following technical solutions:

[0007] The system includes multiple single cells and control units, wherein the single cells are connected to the control units in a one-to-one correspondence, and the control units are interconnected via a CAN bus;

[0008] The control unit is used to send its own ID signal to the system via the CAN bus, and receive ID signals sent by other control units in the system via the CAN bus. The control unit establishes communication with each control unit in the system;

[0009] The control unit is used to obtain the voltage information of the single cell corresponding to itself and periodically send the voltage information of the single cell corresponding to itself to the system, and is also used to monitor the voltage information of the single cell sent by other control units in the system;

[0010] The control unit is used to obtain the system charge and discharge status based on the charge and discharge status of its corresponding single battery; and adjust the switching status of the discharge MOS tube and the charge MOS tube of its corresponding single battery based on the voltage of its corresponding single battery and the voltages of other single batteries in the system.

[0011] By adopting the above technical solution and through communication between the control units in the system, the battery system can adjust the charging and discharging speed of the single battery by adjusting the switching states of the discharge MOS tube and the charging MOS tube according to the actual voltage of each single battery during the charging and discharging process, so as to make the voltage of each single battery tend to be balanced and consistent, thereby reducing the gap between the actual cruising range and the theoretical cruising range of the vehicle and ensuring the cruising range of the vehicle.

[0012] In a specific implementation scheme, the control unit adjusts the switching states of the discharge MOS tube and the charge MOS tube of the corresponding single cell based on the voltage of the single cell corresponding to the control unit and the voltage of other single cells in the system, specifically including:

[0013] When the system is in a discharging state, the control unit compares the voltage of the single cell corresponding to itself with the voltages of other single cells in the system to determine whether the voltage of the single cell corresponding to itself is the largest;

[0014] If so, the control unit turns on the charging MOS tube of the corresponding single battery, so that the discharge current of the single battery corresponding to the control unit flows out through the discharge MOS tube and the charging MOS tube;

[0015] If not, the control unit obtains the discharge current of the single cell corresponding to itself, and calculates the voltage difference ΔV based on the voltage of the single cell corresponding to itself and the voltage of other single cells in the system, and determines the magnitude of the discharge current of the single cell corresponding to itself and the first preset current threshold, as well as the magnitude of the voltage difference ΔV and the first preset pressure difference threshold; if the discharge current is greater than the first preset current threshold and the voltage difference ΔV is less than the first preset pressure difference threshold, the control unit turns on the charging MOS tube of the single cell corresponding to itself, so that the discharge current of the single cell corresponding to the control unit flows out through the discharge MOS tube and the charging MOS tube.

[0016] By adopting the above technical solution, when the charging MOS tube of the single battery is turned on, the discharging current of the single battery can flow out through the discharging MOS tube and the charging MOS tube, and the discharging current does not need to pass through the body diode of the charging MOS tube, thereby accelerating the discharging speed of the single battery, accelerating the discharging speed of the single battery with a larger battery voltage or a larger discharging current, and ensuring that the voltages of the single batteries in the system tend to be consistent.

[0017] In a specific implementation, the control unit adjusts the on-off state of the discharging MOS tube and the charging MOS tube of the single battery corresponding to the control unit based on the voltage of the single battery corresponding to the control unit and the voltages of the other single batteries in the system, and specifically further includes:

[0018] When the system is in a charging state, the control unit compares the voltage of the single battery corresponding to the control unit with the voltages of the other single batteries in the system to determine whether the voltage of the single battery corresponding to the control unit is the smallest.

[0019] If yes, the control unit turns on the discharging MOS tube of the single battery corresponding to the control unit, so that the charging current of the single battery corresponding to the control unit flows in through the charging MOS tube and the discharging MOS tube.

[0020] If no, the control unit acquires the charging current of the single battery corresponding to the control unit, calculates a pressure difference AV based on the voltage of the single battery corresponding to the control unit and the voltages of the other single batteries in the system, and determines the size of the charging current of the single battery corresponding to the control unit and the second preset current threshold value and the size of the pressure difference AV and the second preset pressure difference threshold value; if the charging current > the second preset current threshold value and the pressure difference AV < the second preset pressure difference threshold value, the control unit turns on the discharging MOS tube of the single battery corresponding to the control unit, so that the charging current of the single battery corresponding to the control unit flows in through the charging MOS tube and the discharging MOS tube.

[0021] By adopting the above technical solution, when the charging MOS tube of the single battery is turned on, the discharging current of the single battery can flow out through the discharging MOS tube and the charging MOS tube, and the discharging current does not need to pass through the body diode of the charging MOS tube, thereby accelerating the discharging speed of the single battery, accelerating the discharging speed of the single battery with a larger battery voltage or a larger discharging current, and ensuring that the voltages of the single batteries in the system tend to be consistent.

[0022] In a specific implementation, when the battery system is connected to a new single battery, the control unit corresponding to the new single battery is connected to the control units corresponding to the original single batteries in the battery system through a CAN bus.

[0023] The control unit corresponding to the new single battery is used to send its own ID signal to the system via the CAN bus, and receive ID signals sent by other control units in the system via the CAN bus. The control unit corresponding to the new single battery establishes communication with the control unit corresponding to the original single battery in the system;

[0024] The control unit corresponding to the new single cell and the control unit corresponding to the original single cell are both used to obtain the voltage information of the single cell corresponding to themselves, and periodically send the voltage information of the single cell corresponding to themselves to the system, and are also used to monitor the voltage information of the single cell sent by other control units in the system;

[0025] The control unit corresponding to the original single cell is used to obtain the system charge and discharge status based on the charge and discharge status of the original single cell corresponding to itself; and adjust the switch status of the discharge MOS tube and the charge MOS tube of the original single cell corresponding to itself based on the voltage of the original single cell corresponding to itself and the voltage of the new single cell;

[0026] The control unit corresponding to the new single cell is used to obtain the system charge and discharge status based on the charge and discharge status of the new single cell corresponding to itself; and adjust the switching status of the discharge MOS tube and the charge MOS tube of the new single cell corresponding to itself based on the voltage of the new single cell corresponding to itself and the voltage of the original single cell.

[0027] By adopting the above technical solution, when a new single cell battery is connected to the system, the same method is used to enable all control units in the system to communicate with each other, and the control unit corresponding to the original single cell battery and the control unit corresponding to the new single cell battery respectively perform corresponding adjustment actions according to the voltage conditions of each single cell battery in the system to adjust the charging and discharging speed of the single cell battery, so that when the new single cell battery is connected to the system, the voltage of each single cell battery is still guaranteed to be balanced and consistent.

[0028] In a specific possible implementation scheme, the control unit corresponding to the original single cell adjusts the switching states of the discharge MOS tube and the charge MOS tube of the corresponding original single cell based on the voltage of the corresponding original single cell and the voltage of the new single cell, specifically including:

[0029] When the system is in a discharging state, the control unit corresponding to the original single cell compares the voltage of the original single cell corresponding to itself with the voltage of the new single cell, and determines whether the voltage of the original single cell corresponding to itself is less than the voltage of the new single cell;

[0030] If so, the control unit corresponding to the original single battery disconnects the charging MOS tube and the discharging MOS tube of the original single battery corresponding to itself;

[0031] If not, the control unit corresponding to the original single cell turns on the charging MOS tube of the original single cell corresponding to itself, so that the discharge current of the original single cell flows out through the body diode of the discharge MOS tube and the charging MOS tube.

[0032] By adopting the above technical solution, when discharging, after a new single cell is connected, the control unit corresponding to the original single cell in the system performs comparison and control operations. By comparing the voltage of its own original single cell with the voltage of the new single cell, if the voltage of the original single cell is smaller, the discharge MOS tube and the charging MOS tube of the original single cell are disconnected to avoid mutual charging; if the voltage of the original single cell is larger, the discharge speed is automatically accelerated.

[0033] In a specific possible implementation scheme, the control unit corresponding to the original single cell adjusts the switching states of the discharge MOS tube and the charge MOS tube of the corresponding single cell based on the voltage of the single cell corresponding to the original cell and the voltage of the new single cell, which specifically further includes:

[0034] The control unit corresponding to the original single cell adjusts the switching states of the discharge MOS tube and the charge MOS tube of the corresponding original single cell based on the voltage of the corresponding original single cell and the voltage of the new single cell, and specifically further includes:

[0035] When the system is in a charging state, the control unit corresponding to the original single cell compares the voltage of the original single cell corresponding to itself with the voltage of the new single cell, and determines whether the voltage of the original single cell corresponding to itself is greater than the voltage of the new single cell;

[0036] If so, the control unit corresponding to the original single cell disconnects the discharge MOS tube of the original single cell corresponding to itself, so that the charging current of the original single cell flows into the body diode of the charging MOS tube and the discharge MOS tube;

[0037] If not, the control unit corresponding to the original single cell turns on the discharge MOS tube of the original single cell corresponding to itself, so that the charging current of the original single cell flows through the charging MOS tube and the charging MOS tube.

[0038] By adopting the above technical solution, when charging, after a new single cell battery is connected, the control unit corresponding to the original single cell battery in the system performs comparison and control operations. By comparing the voltage of its own original single cell battery with the voltage of the new single cell battery, the charging speed is automatically reduced when the voltage of the original single cell battery is larger; and the discharging speed is automatically accelerated when the voltage of the original single cell battery is smaller.

[0039] In a specific implementation scheme, the control unit corresponding to the new single cell adjusts the switching states of the discharge MOS tube and the charge MOS tube of the new single cell corresponding to itself based on the voltage of the new single cell corresponding to itself and the voltage of the original single cell, specifically including:

[0040] When the system is in a discharging state, the control unit corresponding to the new single cell compares the voltage of the new single cell corresponding to itself with the voltage of the original single cell, and determines whether the voltage of the new single cell corresponding to itself is greater than the voltage of the original single cell;

[0041] If yes, the control unit corresponding to the new single cell turns on the discharge MOS tube of the new single cell corresponding to itself, so that the discharge current of the new single cell flows out through the discharge MOS tube and the charge MOS tube;

[0042] If not, the control unit corresponding to the new single cell disconnects the discharge MOS tube and the charge MOS tube of the new single cell corresponding to itself.

[0043] By adopting the above technical solution, when discharging, after a new single cell battery is connected, the control unit corresponding to the new single cell battery in the system performs comparison and control operations. By comparing the voltage of the new single cell battery with the voltage of the original single cell battery, when the voltage of the new single cell battery is larger, the discharge speed is automatically increased. When the voltage of the new single cell battery is smaller, the discharge MOS tube and the charging MOS tube are automatically disconnected to avoid mutual charging.

[0044] In a specific implementation scheme, the control unit corresponding to the new single cell adjusts the switching states of the discharge MOS tube and the charge MOS tube of the new single cell corresponding to itself based on the voltage of the new single cell corresponding to itself and the voltage of the original single cell, specifically including:

[0045] When the system is in a charging state, the control unit corresponding to the new single cell compares the voltage of the new single cell corresponding to itself with the voltage of the original single cell, and determines whether the voltage of the new single cell corresponding to itself is less than the voltage of the original single cell;

[0046] If so, the control unit corresponding to the new single cell turns on the charging MOS tube of the new single cell corresponding to itself, so that the charging current of the new single cell flows out through the charging MOS tube and the discharging MOS tube;

[0047] If not, the control unit corresponding to the new single cell disconnects the discharge MOS tube of the corresponding new single cell, so that the charging current of the new single cell flows through the body diodes of the charging MOS tube and the discharge MOS tube.

[0048] By adopting the above technical solution, when charging, after a new single cell battery is connected, the control unit corresponding to the new single cell battery in the system performs comparison and control operations. By comparing the voltage of the new single cell battery itself with the voltage of the original single cell battery, the charging speed is automatically increased when the voltage of the new single cell battery is smaller; and the charging speed is reduced when the voltage of the new single cell battery is larger.

[0049] In summary, the technical solution of this application includes at least the following beneficial technical effects:

[0050] 1. Through communication between the control units within the system, the battery system can adjust the charging and discharging speed of the single battery by adjusting the switching state of the discharge MOS tube and the charge MOS tube according to the actual voltage of each single battery during the charging and discharging process, so that the voltage of each single battery tends to be balanced and consistent, thereby reducing the gap between the actual cruising range and the theoretical cruising range of the vehicle and ensuring the vehicle's cruising range;

[0051] 2. When a new single cell battery is connected to the system, all control units in the system communicate with each other, and the control units corresponding to the original single cell battery and the control units corresponding to the new single cell battery respectively perform corresponding adjustment actions according to the voltage conditions of each single cell battery in the system to adjust the charge and discharge speed of the single cell battery, so that when the new single cell battery is connected to the system, the voltage of each single cell battery is still balanced and consistent. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 is a structural diagram of a battery system in an embodiment of the present application;

[0053] Figure 2 (a) is a schematic diagram of the current flow in the discharge circuit of a single battery in an embodiment of the present application; Figure 2 (b) is a schematic diagram of current flow in a single battery charging circuit in an embodiment of the present application;

[0054] Figure 3 This is a flow chart of adjusting the switch state of a charging and discharging MOS tube in an embodiment of the present application;

[0055] Figure 4 This is a schematic diagram of the process of adjusting the charging and discharging MOS tube switch state of the original single battery in the embodiment of the present application;

[0056] Figure 5 This is a flow chart of adjusting the charging and discharging MOS tube switch state for a new single cell in an embodiment of the present application. DETAILED DESCRIPTION

[0057] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0058] The embodiment of the present application provides a battery system with automatic charge-discharge balance, referring to Figure 1 The system comprises a plurality of single batteries and control units, the single batteries are connected with the control units one by one, and the control units are connected with each other through CAN bus;

[0059] The control unit is used for sending an ID signal of itself to the system through the CAN bus, and receiving an ID signal sent by other control units in the system through the CAN bus, and the control unit establishes communication with each control unit in the system;

[0060] The control unit is used for obtaining single battery voltage information corresponding to the control unit, periodically sending the single battery voltage information corresponding to the control unit to the system, and listening to single battery voltage information sent by other control units in the system;

[0061] The control unit is used for obtaining a system charge-discharge state based on a charge-discharge state of the single battery corresponding to the control unit, and adjusting switch states of a discharge MOS tube and a charge MOS tube of the single battery corresponding to the control unit based on the single battery voltage corresponding to the control unit and other single battery voltages in the system, so as to adjust a charge-discharge speed of the single battery.

[0062] Specifically, each control unit carries out data interaction in the form of a data message.

[0063] Therefore, through communication between the control units in the system, the battery system can adjust the charge-discharge speed of the single battery by adjusting the switch states of the discharge MOS tube and the charge MOS tube during the charge-discharge process according to actual voltage conditions of the single batteries, so that the voltages of the single batteries tend to be balanced and consistent, thereby reducing a difference between an actual cruising range and a theoretical cruising range of the vehicle and ensuring the cruising range of the vehicle.

[0064] In a possible implementation, referring to Figure 3 The control unit adjusts the switch states of the discharge MOS tube and the charge MOS tube of the single battery corresponding to the control unit based on the single battery voltage corresponding to the control unit and other single battery voltages in the system, and specifically comprises the following steps:

[0065] When the system is in a discharge state, the control unit compares the single battery voltage corresponding to the control unit with other single battery voltages in the system, and judges whether the single battery voltage corresponding to the control unit is the largest;

[0066] If yes, the control unit turns on the charge MOS tube of the single battery corresponding to the control unit, so that a discharge current of the single battery corresponding to the control unit flows out through the discharge MOS tube and the charge MOS tube, thereby accelerating the discharge speed of the single battery;

[0067] If not, the control unit obtains the discharge current of the single cell corresponding to itself, and calculates the voltage difference ΔV based on the voltage of the single cell corresponding to itself and the voltage of other single cells in the system, and determines the magnitude of the discharge current of the single cell corresponding to itself and the first preset current threshold, as well as the magnitude of the voltage difference ΔV and the first preset voltage difference threshold; if the discharge current is greater than the first preset current threshold and the voltage difference ΔV is less than the first preset voltage difference threshold, indicating that the discharge speed of the single cell also needs to be accelerated, the control unit turns on the charging MOS tube of the single cell corresponding to itself, so that the discharge current of the single cell corresponding to the control unit flows out through the discharge MOS tube and the charging MOS tube, thereby accelerating the discharge speed of the single cell.

[0068] The voltage difference ΔV is the difference between the single cell voltage corresponding to the control unit itself and the single cell voltage corresponding to other control units in the system.

[0069] Specifically, refer to Figure 2 In (a), the single cell is connected to the discharge MOS transistor and the charge MOS transistor in sequence. When the system is in the discharge state, the discharge MOS transistor of the single cell is turned on by default, and the discharge current of the single cell flows out through the body diodes of the discharge MOS transistor and the charge MOS transistor. Through the above judgment and control process, when the charge MOS transistor of the single cell is turned on, the discharge current of the single cell can flow out through the discharge MOS transistor and the charge MOS transistor. The discharge current does not need to pass through the body diode of the charge MOS transistor, thereby accelerating the discharge speed of the single cell, so that the single cell with a larger battery voltage or a larger discharge current has a faster discharge speed, ensuring that the voltages of all single cells in the system tend to be consistent.

[0070] In a possible implementation, the control unit adjusts the switching states of the discharge MOS transistor and the charge MOS transistor of the corresponding single cell based on the voltage of the single cell corresponding to the control unit and the voltages of other single cells in the system, specifically including:

[0071] When the system is in a charging state, the control unit compares the voltage of the single cell corresponding to itself with the voltages of other single cells in the system to determine whether the voltage of the single cell corresponding to itself is the smallest;

[0072] If so, the control unit turns on the discharge MOS tube of the corresponding single battery, so that the charging current of the single battery corresponding to the control unit flows through the charging MOS tube and the discharge MOS tube, thereby accelerating the charging speed of the single battery;

[0073] If not, the control unit obtains the charging current of the single cell corresponding to itself, and calculates the voltage difference △V based on the voltage of the single cell corresponding to itself and the voltage of other single cells in the system, and determines the magnitude of the charging current of the single cell corresponding to itself and the second preset current threshold, as well as the magnitude of the voltage difference △V and the second preset voltage difference threshold; if the charging current is greater than the second preset current threshold and the voltage difference △V is less than the second preset voltage difference threshold, indicating that the charging speed of the single cell also needs to be accelerated, the control unit turns on the discharge MOS tube of the single cell corresponding to itself, so that the charging current of the single cell corresponding to the control unit flows through the charging MOS tube and the discharge MOS tube, thereby accelerating the charging speed of the single cell.

[0074] Therefore, refer to Figure 2 In (b), the single cell is connected to the discharge MOS tube and the charge MOS tube in sequence. When the system is in the charging state, the charge MOS tube of the single cell is turned on by default, and the charging current of the single cell flows in through the body diodes of the charge MOS tube and the discharge MOS tube. Through the above judgment and control process, when the discharge MOS tube of the single cell is turned on, the charging current of the single cell can flow in through the charge MOS tube and the discharge MOS tube. The charging current does not need to pass through the body diode of the discharge MOS tube, thereby accelerating the charging speed of the single cell, so that the single cell with a smaller battery voltage or a larger charging current is charged faster, ensuring that the voltages of each single cell in the system tend to be consistent.

[0075] In one possible embodiment, the values ​​of the first current threshold and the second current threshold are determined based on factors such as the current size and power size that the body diode of the charging MOS tube and the body diode of the discharging MOS tube can withstand; the sizes of the first preset pressure difference threshold and the second preset pressure difference threshold are determined based on the type and characteristics of the single battery; exemplarily, for iron-lithium batteries, the first preset pressure difference threshold and the second preset pressure difference threshold are relatively small, and for ternary batteries, the first preset pressure difference threshold and the second preset pressure difference threshold are relatively large.

[0076] In one possible implementation, refer to Figure 1 When a new single cell is connected to the battery system, the control unit corresponding to the new single cell is connected to the control unit corresponding to the original single cell in the battery system via the CAN bus, thereby forming a new battery system;

[0077] The same communication method as before the new single cell battery is connected is used. The control unit corresponding to the new single cell battery is used to send its own ID signal to the system via the CAN bus and receive ID signals sent by other control units in the system via the CAN bus. The control unit corresponding to the new single cell battery establishes communication with the control unit corresponding to the original single cell battery in the system.

[0078] The control unit corresponding to the new single cell and the control unit corresponding to the original single cell are both used to obtain the voltage information of the single cell corresponding to themselves, and periodically send the voltage information of the single cell corresponding to themselves to the system, and are also used to monitor the voltage information of the single cell sent by other control units in the system;

[0079] The control unit corresponding to the original single cell is used to obtain the system charge and discharge status based on the charge and discharge status of the original single cell corresponding to itself; and adjust the switch status of the discharge MOS tube and the charge MOS tube of the original single cell corresponding to itself based on the voltage of the original single cell corresponding to itself and the voltage of the new single cell;

[0080] The control unit corresponding to the new single cell is used to obtain the system charge and discharge status based on the charge and discharge status of the new single cell corresponding to itself; and adjust the switching status of the discharge MOS tube and the charge MOS tube of the new single cell corresponding to itself based on the voltage of the new single cell corresponding to itself and the voltage of the original single cell.

[0081] Therefore, when a new single cell battery is connected to the system, the same method is used to enable all control units in the system to communicate with each other, and the control unit corresponding to the original single cell battery and the control unit corresponding to the new single cell battery respectively perform corresponding adjustment actions according to the voltage conditions of each single cell battery in the system to adjust the charging and discharging speed of the single cell battery, so that when a new single cell battery is connected to the system, the voltage of each single cell battery is still guaranteed to be balanced and consistent.

[0082] In one possible implementation, refer to Figure 4 The control unit corresponding to the original single cell adjusts the switching states of the discharge MOS tube and the charge MOS tube of the corresponding original single cell based on the voltage of the corresponding original single cell and the voltage of the new single cell, specifically including:

[0083] When the system is in a discharging state, the control unit corresponding to the original single cell compares the voltage of the original single cell corresponding to itself with the voltage of the new single cell, and determines whether the voltage of the original single cell corresponding to itself is less than the voltage of the new single cell;

[0084] If so, the control unit corresponding to the original single cell disconnects the charging MOS tube and the discharging MOS tube of the original single cell corresponding to itself. In this case, since the voltage of the original single cell is relatively low and the system is in a discharging state, by disconnecting the discharging MOS tube and the charging MOS tube of the original single cell corresponding to itself, the phenomenon of mutual charging between the single cells in the system can be effectively avoided.

[0085] If not, the control unit corresponding to the original single battery turns on the charging MOS tube of the original single battery corresponding to itself, so that the discharging current of the original single battery flows out through the body diode of the discharging MOS tube and the charging MOS tube, thereby accelerating the discharging speed of the original single battery, and avoiding that the original single battery has a slow discharging speed in the case that the voltage of the original single battery is greater than the voltage of the newly connected single battery.

[0086] Therefore, through the above control process, when discharging, after the newly connected single battery, the control unit corresponding to the original single battery in the system performs comparison and control operations, compares the voltage of the original single battery with the voltage of the newly connected single battery, and in the case that the voltage of the original single battery is smaller, turns off the discharging MOS tube and the charging MOS tube of the original single battery, thereby avoiding mutual charging; in the case that the voltage of the original single battery is greater, automatically accelerates the discharging speed.

[0087] In a possible implementation, continuing to refer to Figure 4 , the control unit corresponding to the original single battery adjusts the on-off state of the discharging MOS tube and the charging MOS tube of the original single battery corresponding to itself based on the voltage of the original single battery corresponding to itself and the voltage of the newly connected single battery, and specifically further includes:

[0088] When the system is in the charging state, the control unit corresponding to the original single battery compares the voltage of the original single battery corresponding to itself with the voltage of the newly connected single battery, and judges whether the voltage of the original single battery corresponding to itself is greater than the voltage of the newly connected single battery.

[0089] If yes, the control unit corresponding to the original single battery turns off the discharging MOS tube of the original single battery corresponding to itself, so that the charging current of the original single battery flows in through the body diode of the charging MOS tube and the discharging MOS tube, thereby reducing the charging speed of the original single battery, and avoiding that the original single battery still has a fast charging speed in the case that the voltage of the original single battery is greater than the voltage of the newly connected single battery.

[0090] If not, the control unit corresponding to the original single battery turns on the discharging MOS tube of the original single battery corresponding to itself, so that the charging current of the original single battery flows in through the charging MOS tube and the charging MOS tube, thereby accelerating the charging speed of the original single battery, and avoiding that the original single battery has a slow charging speed in the case that the voltage of the original single battery is smaller than the voltage of the newly connected single battery.

[0091] Therefore, through the above control process, when charging, after the newly connected single battery, the control unit corresponding to the original single battery in the system performs comparison and control operations, compares the voltage of the original single battery with the voltage of the newly connected single battery, and in the case that the voltage of the original single battery is greater, automatically reduces the charging speed; in the case that the voltage of the original single battery is smaller, automatically accelerates the discharging speed.

[0092] In one possible implementation, refer to Figure 5 The control unit corresponding to the new single cell adjusts the switching states of the discharge MOS tube and the charge MOS tube of the new single cell corresponding to the new single cell based on the voltage of the new single cell corresponding to the new single cell and the voltage of the original single cell, specifically including:

[0093] When the system is in a discharging state, the control unit corresponding to the new single cell compares the voltage of the new single cell corresponding to itself with the voltage of the original single cell, and determines whether the voltage of the new single cell corresponding to itself is greater than the voltage of the original single cell;

[0094] If so, the control unit corresponding to the new single cell turns on the discharge MOS tube of the new single cell corresponding to itself, so that the discharge current of the new single cell flows out through the discharge MOS tube and the charge MOS tube, thereby increasing the discharge speed of the new single cell and preventing the new single cell from discharging more slowly when the voltage of the new single cell is higher than that of the original single cell.

[0095] If not, the control unit corresponding to the new single cell disconnects the discharge MOS tube and the charge MOS tube of the new single cell corresponding to itself; in this case, since the voltage of the new single cell is relatively small and the system is in a discharge state, by disconnecting the discharge MOS tube and the charge MOS tube of the new single cell corresponding to itself, the mutual charging phenomenon between the single cells in the system can be effectively avoided.

[0096] Therefore, through the above control process, when discharging, after a new single cell battery is connected, the control unit corresponding to the new single cell battery in the system performs comparison and control operations. By comparing the voltage of its own new single cell battery with the voltage of the original single cell battery, when the voltage of the new single cell battery is larger, the discharge speed is automatically increased. When the voltage of the new single cell battery is smaller, the discharge MOS tube and the charging MOS tube are automatically disconnected to avoid mutual charging.

[0097] In one possible implementation, continue to refer to Figure 5 The control unit corresponding to the new single cell adjusts the switching states of the discharge MOS tube and the charge MOS tube of the new single cell corresponding to the new single cell based on the voltage of the new single cell corresponding to the new single cell and the voltage of the original single cell, specifically including:

[0098] When the system is in a charging state, the control unit corresponding to the new single cell compares the voltage of the new single cell corresponding to itself with the voltage of the original single cell, and determines whether the voltage of the new single cell corresponding to itself is less than the voltage of the original single cell;

[0099] If so, the control unit corresponding to the new single cell turns on the charging MOS transistor of the new single cell corresponding to itself, so that the charging current of the new single cell flows out through the charging MOS transistor and the discharging MOS transistor, thereby increasing the charging speed of the new single cell and preventing the new single cell from charging more slowly when the voltage of the new single cell is lower than that of the original single cell.

[0100] If not, the control unit corresponding to the new single cell disconnects the discharge MOS tube of the corresponding new single cell, so that the charging current of the new single cell flows through the body diodes of the charging MOS tube and the discharge MOS tube, thereby reducing the charging speed of the new single cell and preventing the new single cell from maintaining a faster charging speed when the voltage of the new single cell is higher than that of the original single cell.

[0101] Therefore, through the above control process, when charging, after a new single cell battery is connected, the control unit corresponding to the new single cell battery in the system performs comparison and control operations. By comparing the voltage of the new single cell battery itself with the voltage of the original single cell battery, the charging speed is automatically increased when the voltage of the new single cell battery is smaller; and the charging speed is reduced when the voltage of the new single cell battery is larger.

[0102] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A battery system with automatic charge and discharge balancing, characterized in that: It includes multiple single cells and control units, wherein the single cells are connected to the control units in a one-to-one correspondence, and the control units are interconnected via a CAN bus; The control unit is used to send its own ID signal to the system via the CAN bus, and receive ID signals sent by other control units in the system via the CAN bus. The control unit establishes communication with each control unit in the system; The control unit is used to obtain the voltage information of the single cell corresponding to itself and periodically send the voltage information of the single cell corresponding to itself to the system, and is also used to monitor the voltage information of the single cell sent by other control units in the system; The control unit is configured to obtain the system charge and discharge status based on the charge and discharge status of its corresponding single cell; and based on the voltage of its corresponding single cell and the voltages of other single cells in the system, change the current path by adjusting the switching states of the discharge MOS transistor and the charge MOS transistor of its corresponding single cell, thereby adjusting the charge and discharge speed of its corresponding single cell. When the system is in a discharge state, the current path includes the discharge current of the single cell being discharged through the discharge MOS transistor and the charge MOS transistor, and also includes the discharge current of the single cell being discharged through the body diodes of the discharge MOS transistor and the charge MOS transistor. When the system is in a charge state, the current path includes the charging current of the single cell being charged through the body diodes of the charge MOS transistor and the discharge MOS transistor, and also includes the charging current of the single cell being charged through the charge MOS transistor and the discharge MOS transistor. When a new single cell is connected to the battery system, the control unit corresponding to the new single cell is interconnected with the control unit corresponding to the original single cell in the battery system via a CAN bus. The control unit corresponding to the new single battery is used to send its own ID signal to the system via the CAN bus, and receive ID signals sent by other control units in the system via the CAN bus. The control unit corresponding to the new single battery establishes communication with the control unit corresponding to the original single battery in the system; The control unit corresponding to the new single cell and the control unit corresponding to the original single cell are both used to obtain the voltage information of the single cell corresponding to themselves, and periodically send the voltage information of the single cell corresponding to themselves to the system, and are also used to monitor the voltage information of the single cell sent by other control units in the system; The control unit corresponding to the original single cell is used to obtain the system charge and discharge status based on the charge and discharge status of the corresponding original single cell; and based on the voltage of the corresponding original single cell and the voltage of the new single cell, by adjusting the switching states of the discharge MOS transistor and the charge MOS transistor of the corresponding original single cell, the current path is changed, thereby adjusting the charge and discharge speed of the corresponding original single cell; The control unit corresponding to the new single cell is used to obtain the system charge and discharge status based on the charge and discharge status of the new single cell corresponding to itself; and based on the voltage of the new single cell corresponding to itself and the voltage of the original single cell, by adjusting the switching states of the discharge MOS tube and the charge MOS tube of the new single cell corresponding to itself, the current path is changed, thereby adjusting the charge and discharge speed of the new single cell corresponding to itself.

2. The battery system with automatic charge and discharge balancing according to claim 1, characterized in that: The control unit adjusts the switching states of the discharge MOS tube and the charge MOS tube of the corresponding single cell based on the voltage of the single cell corresponding to the control unit and the voltages of other single cells in the system, specifically including: When the system is in a discharging state, the control unit compares the voltage of the single cell corresponding to itself with the voltages of other single cells in the system to determine whether the voltage of the single cell corresponding to itself is the largest; If so, the control unit turns on the charging MOS tube of the corresponding single battery, so that the discharge current of the single battery corresponding to the control unit flows out through the discharge MOS tube and the charging MOS tube; If not, the control unit obtains the discharge current of the single cell corresponding to itself, and calculates the voltage difference ΔV based on the voltage of the single cell corresponding to itself and the voltage of other single cells in the system, and determines the magnitude of the discharge current of the single cell corresponding to itself and the first preset current threshold, as well as the magnitude of the voltage difference ΔV and the first preset pressure difference threshold; if the discharge current is greater than the first preset current threshold and the voltage difference ΔV is less than the first preset pressure difference threshold, the control unit turns on the charging MOS tube of the single cell corresponding to itself, so that the discharge current of the single cell corresponding to the control unit flows out through the discharge MOS tube and the charging MOS tube.

3. The battery system with automatic charge and discharge balancing according to claim 1, characterized in that: The control unit adjusts the switching states of the discharge MOS transistor and the charge MOS transistor of the corresponding single cell based on the voltage of the single cell corresponding to the control unit and the voltages of other single cells in the system, and specifically includes: When the system is in a charging state, the control unit compares the voltage of the single cell corresponding to itself with the voltages of other single cells in the system to determine whether the voltage of the single cell corresponding to itself is the smallest; If so, the control unit turns on the discharge MOS tube of the corresponding single battery, so that the charging current of the single battery corresponding to the control unit flows through the charging MOS tube and the discharge MOS tube; If not, the control unit obtains the charging current of the single cell corresponding to itself, and calculates the voltage difference △V based on the voltage of the single cell corresponding to itself and the voltage of other single cells in the system, and determines the size of the charging current of the single cell corresponding to itself and the second preset current threshold, as well as the size of the voltage difference △V and the second preset pressure difference threshold; if the charging current is greater than the second preset current threshold and the voltage difference △V is less than the second preset pressure difference threshold, the control unit turns on the discharge MOS tube of the single cell corresponding to itself, so that the charging current of the single cell corresponding to the control unit flows through the charging MOS tube and the discharging MOS tube.

4. The battery system with automatic charge and discharge balancing according to claim 1, characterized in that: The control unit corresponding to the original single cell adjusts the switching states of the discharge MOS tube and the charge MOS tube of the corresponding original single cell based on the voltage of the corresponding original single cell and the voltage of the new single cell, specifically including: When the system is in a discharging state, the control unit corresponding to the original single cell compares the voltage of the original single cell corresponding to itself with the voltage of the new single cell, and determines whether the voltage of the original single cell corresponding to itself is less than the voltage of the new single cell; If so, the control unit corresponding to the original single battery disconnects the charging MOS tube and the discharging MOS tube of the original single battery corresponding to itself; If not, the control unit corresponding to the original single cell turns on the charging MOS tube of the original single cell corresponding to itself, so that the discharge current of the original single cell flows out through the body diode of the discharge MOS tube and the charging MOS tube.

5. The battery system with automatic charge and discharge balancing according to claim 1, characterized in that: The control unit corresponding to the original single cell adjusts the switching states of the discharge MOS tube and the charge MOS tube of the corresponding original single cell based on the voltage of the corresponding original single cell and the voltage of the new single cell, and specifically further includes: When the system is in a charging state, the control unit corresponding to the original single cell compares the voltage of the original single cell corresponding to itself with the voltage of the new single cell, and determines whether the voltage of the original single cell corresponding to itself is greater than the voltage of the new single cell; If so, the control unit corresponding to the original single cell disconnects the discharge MOS tube of the original single cell corresponding to itself, so that the charging current of the original single cell flows into the body diode of the charging MOS tube and the discharge MOS tube; If not, the control unit corresponding to the original single cell turns on the discharge MOS tube of the original single cell corresponding to itself, so that the charging current of the original single cell flows through the charging MOS tube and the charging MOS tube.

6. The battery system according to claim 1, wherein: The control unit corresponding to the new single cell adjusts the switching states of the discharge MOS tube and the charge MOS tube of the new single cell corresponding to the new single cell based on the voltage of the new single cell corresponding to the new single cell and the voltage of the original single cell, specifically including: When the system is in a discharging state, the control unit corresponding to the new single cell compares the voltage of the new single cell corresponding to itself with the voltage of the original single cell, and determines whether the voltage of the new single cell corresponding to itself is greater than the voltage of the original single cell; If yes, the control unit corresponding to the new single cell turns on the discharge MOS tube of the new single cell corresponding to itself, so that the discharge current of the new single cell flows out through the discharge MOS tube and the charge MOS tube; If not, the control unit corresponding to the new single cell disconnects the discharge MOS tube and the charge MOS tube of the new single cell corresponding to itself.

7. The battery system according to claim 1, characterized in that The control unit corresponding to the new single cell adjusts the switching states of the discharge MOS tube and the charge MOS tube of the new single cell corresponding to the new single cell based on the voltage of the new single cell corresponding to the new single cell and the voltage of the original single cell, specifically including: When the system is in a charging state, the control unit corresponding to the new single cell compares the voltage of the new single cell corresponding to itself with the voltage of the original single cell, and determines whether the voltage of the new single cell corresponding to itself is less than the voltage of the original single cell; If so, the control unit corresponding to the new single cell turns on the charging MOS tube of the new single cell corresponding to itself, so that the charging current of the new single cell flows out through the charging MOS tube and the discharging MOS tube; If not, the control unit corresponding to the new single cell disconnects the discharge MOS tube of the corresponding new single cell, so that the charging current of the new single cell flows through the body diodes of the charging MOS tube and the discharge MOS tube.

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