Battery pack, battery management system and vehicle

Abstract

The present invention provides a battery pack, a battery management system and a vehicle, wherein the battery pack includes: a battery pack, a switch module, a current limiting module and a control module, wherein the battery pack is electrically connected to the switch module, the current limiting module is connected in parallel to the switch module, and the control module is electrically connected to the switch module and the current limiting module respectively; the battery pack is electrically connected to an external power supply through the switch module, or the battery pack is electrically connected to an external power supply through the current limiting module; the control module is used to disconnect the electrical connection between the switch module and the battery pack when the external power supply charges the battery pack, and control the electrical connection between the current limiting module and the battery pack to be connected when the fluctuation of the charging current exceeds a preset threshold. Through the current limiting effect of the current limiting module, the stability of the charging current is improved, the situation of overcharging current due to current fluctuation is reduced, the limitation of the output current can be released, the power consumption of the load end is improved, the situation of load undervoltage is reduced, and thus the safety of the battery pack is improved.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a battery pack, a battery management system and a vehicle. Background Art

[0002] Lithium-ion batteries have been widely used, but in low-temperature environments, such as temperatures below zero degrees Celsius, the charging capacity of lithium-ion batteries will drop rapidly. At this time, if a large current is used to charge the battery, lithium deposition will occur in the battery. Long-term lithium deposition may cause internal short circuits in the battery cell, causing thermal runaway of the battery and leading to safety accidents. At present, the battery pack generally actively sends a request to the on-board DC / DC converter charger to control the charging current and voltage.

[0003] However, when charging the battery, the on-board DC-DC (Direct Current, DC for short) charger also needs to supply power to other loads on the vehicle. During the battery charging process, load fluctuations may easily cause charging current fluctuations, resulting in a large charging current, which may lead to thermal runaway of the battery, especially in low temperature environments, which may easily cause safety accidents.

[0004] It can be seen that the battery pack in the prior art has the problem of poor safety. Summary of the invention

[0005] Embodiments of the present invention provide a battery pack, a battery management system and a vehicle to solve the problem of poor safety of battery packs in the prior art.

[0006] In a first aspect, an embodiment of the present invention provides a battery pack, comprising: a battery pack, a switch module, a current limiting module and a control module, wherein the battery pack is electrically connected to the switch module, the current limiting module is connected in parallel to the switch module, and the control module is electrically connected to the switch module and the current limiting module respectively;

[0007] The battery pack is electrically connected to the external power supply through the switch module, or the battery pack is electrically connected to the external power supply through the current limiting module;

[0008] The control module is used to disconnect the electrical connection between the switch module and the battery pack and control the electrical connection between the current limiting module and the battery pack to be connected when the battery pack is charged by an external power supply and the fluctuation of the charging current exceeds a preset threshold.

[0009] Optionally, a communication module is also included, and the control module is used to obtain status information of the battery pack. When the battery pack needs to be charged, a charging request is sent to an external power supply through the communication module, and the switch module or the current limiting module is controlled to charge the battery pack according to the status information.

[0010] Optionally, it further includes an information acquisition module, which is connected in series with the battery pack, and the control module obtains the status information of the battery pack through the information acquisition module.

[0011] Optionally, the information acquisition module includes a current information acquisition unit, a voltage information acquisition unit and a temperature information acquisition unit;

[0012] The current information acquisition unit is connected in series with the battery pack, and the control module obtains the current state information of the battery pack through the current information acquisition unit;

[0013] The voltage information acquisition unit is connected in series with the battery pack, and the control module obtains the voltage status information of the battery pack through the voltage information acquisition unit;

[0014] The temperature information acquisition unit is connected in series with the battery pack, and the control module obtains the temperature status information of the battery pack through the temperature information acquisition unit.

[0015] Optionally, the current limiting module is provided with a current limiting driving circuit, and the control module is electrically connected to the current limiting driving circuit;

[0016] The current limiting module includes an energy storage inductor, a first switch tube and a second switch tube, wherein the first end of the first switch tube is connected to the first end of the energy storage inductor, the second end of the first switch tube is connected to the first interface of the current limiting drive circuit, the first end of the second switch tube is connected to the first end of the energy storage inductor, the second end of the second switch tube is connected to the second interface of the current limiting drive circuit, and the second end of the energy storage inductor is connected to the battery pack;

[0017] The control module controls the on-time of the first switch tube and the second switch tube by adjusting the signals of the first interface and the second interface of the current limiting drive circuit, and when the first switch tube is turned on, the second switch tube is turned off, and the energy storage inductor stores energy; when the first switch tube is turned off, the second switch tube is turned on, and the energy storage inductor releases energy.

[0018] Optionally, the current limiting module further includes an input capacitor and an output capacitor, the input capacitor is used to filter the current input to the current limiting module, and the output capacitor is used to filter the current output by the current limiting module.

[0019] Optionally, the current limiting module also includes an anti-reverse switching tube, which is connected in series with the first switching tube. When the first switching tube is turned on, the current passes through the anti-reverse switching tube, the first switching tube and the energy storage inductor in sequence.

[0020] Optionally, the switch module is provided with a charging drive circuit and a discharging drive circuit, and the switch module includes a first charging switch tube, a second charging switch tube, a first discharging switch tube and a second discharging switch tube;

[0021] The first charging switch tube and the first discharging switch tube are connected in series and then connected in parallel with the second charging switch tube and the second discharging switch tube, and the first charging switch tube and the second charging switch tube are connected to the charging drive circuit, the first discharging switch tube and the second discharging switch tube are connected to the discharging drive circuit, and the discharging drive circuit and the charging drive circuit are respectively connected to the control module;

[0022] When the battery pack is charged, the control module controls the start and stop of the charging state through the charging drive circuit;

[0023] When the battery pack is discharging, the control module controls the start and stop of the discharging state through the discharge driving circuit.

[0024] In a second aspect, an embodiment of the present invention further provides a battery management system, comprising the above-mentioned battery pack, wherein the battery pack is connected to the circuit of an on-board charger and an on-board load of the battery management system.

[0025] In a third aspect, an embodiment of the present invention further provides a vehicle, comprising the above-mentioned battery management system.

[0026] In the embodiment of the present invention, a current limiting module is provided in the battery pack. When the external power source is charging the battery pack, and the fluctuation of the charging current exceeds the preset threshold value, the control module can control the disconnection of the electrical connection between the switch module and the battery pack, and control the electrical connection between the current limiting module and the battery pack to be connected, so that the charging current of the external power source passes through the current limiting module, and after the current limiting effect of the current limiting module, it flows through the battery pack to charge the battery pack. Thus, the stability of the charging current when charging the battery pack is improved, the overcharging current due to current fluctuation is reduced, the output current limitation of the vehicle-mounted DC / DC charger can be released, the power consumption of the load end is increased, and the load undervoltage is reduced, thereby improving the safety of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0028] Figure 1 is a structural diagram of a battery pack provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the structures used in this way can be interchanged where appropriate, so that the embodiments of the present invention can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0031] See also Figure 1 , Figure 1 is a schematic diagram of the design principle of the battery pack provided by an embodiment of the present invention, such as Figure 1 As shown, an embodiment of the present invention provides a battery pack 1, which includes: a battery pack 10, a switch module 20, a current limiting module 30 and a control module 40, the battery pack 10 is electrically connected to the switch module 20, the current limiting module 30 is connected in parallel with the switch module 20, and the control module 40 is electrically connected to the switch module 20 and the current limiting module 30 respectively;

[0032] The battery pack 10 is electrically connected to the external power supply through the switch module 20, or the battery pack 10 is electrically connected to the external power supply through the current limiting module 30;

[0033] The control module 40 is used to disconnect the electrical connection between the switch module 20 and the battery pack 10 and connect the electrical connection between the current limiting module 30 and the battery pack 10 when the battery pack 10 is charged by an external power supply and the fluctuation of the charging current exceeds a preset threshold.

[0034] Among them, the battery pack 10 can be composed of 4 lithium batteries connected in series, the battery pack 10 is connected in series with the switch module 20, and the switch module 20 is connected to the positive electrode side of the battery pack 10, and the current limiting module 30 is connected in parallel with the switch module 20; the battery pack 1 can discharge the on-board 12V load 2, and the external power supply can also charge the battery pack 1, the external power supply can be a vehicle-mounted DC / DC converter (DC / DC converter) charger 3, the charging and discharging of the battery pack 1 are controlled by the control module 40, and the control module 40 can be a battery management system (BMS for short). When the external power supply charges the battery pack 10, the BMS collects and manages the information of the battery pack 10. When it is detected that the fluctuation of the charging current exceeds the preset threshold, the control module 40 can disconnect the electrical connection between the switch module 20 and the battery pack 10, and control the electrical connection between the current limiting module 30 and the battery pack 10 to connect, so as to realize the current limiting charging of the battery pack 1.

[0035] In this embodiment, a current limiting module 30 is provided in the battery pack 1. When the external power source charges the battery pack 10 and the fluctuation of the charging current exceeds a preset threshold value, the control module 40 can control the disconnection of the electrical connection between the switch module 20 and the battery pack 10, and control the electrical connection between the current limiting module 30 and the battery pack 10 to be connected, so that the charging current of the external power source passes through the current limiting module 30, and after the current limiting effect of the current limiting module 30, it flows through the battery pack 10 to charge the battery pack 10. Thus, the stability of the charging current when charging the battery pack 10 is improved, the overcharging current due to current fluctuation is reduced, and further, the thermal runaway of the battery pack 10 is reduced, and the safety of the battery pack 1 is improved.

[0036] If the external power source charges the battery pack 10 under good charging conditions and the fluctuation of the charging current does not exceed the preset threshold, there is no need to start the current limiting module 30. The control module 40 can control the disconnection of the electrical connection between the current limiting module 30 and the battery pack 10 and control the connection of the electrical connection between the switch module 20 and the battery pack 10. At this time, the external power source can directly charge the battery pack 10 through the switch module 20. In this way, by setting the current limiting module 30, the stability of the charging current of the battery pack 1 is improved, and overcharging current will not occur due to the fluctuation of the current of the 12V load 2 of the whole vehicle. At the same time, the output current limitation of the vehicle-mounted DC / DC charger 3 can be released, ensuring that the load end has sufficient power consumption, improving the power consumption of the load end, and reducing the occurrence of undervoltage of the load 2.

[0037] Optionally, a communication module 50 is also included, and the control module 40 is used to obtain status information of the battery pack 10. When the battery pack 10 needs to be charged, a charging request is sent to an external power supply through the communication module 50, and the switch module 20 or the current limiting module 30 is controlled to charge the battery pack 10 according to the status information.

[0038] In this embodiment, the status information may include charging current information, voltage information, and battery cell temperature information of the battery pack 10. The battery pack 1 can discharge the on-board 12V load 2. After the battery pack 1 has been discharged for a period of time, the control module 40 detects that the battery pack 10 in the battery pack 1 is in a low-power state, and sends a charging request to the external power supply through the communication module 50. When the charging conditions are good, that is, the temperature is suitable and the current in the circuit is stable, there is no need to start the current limiting module 30. The control module 40 can control the disconnection of the electrical connection between the current limiting module 30 and the battery pack 10, and control the connection of the electrical connection between the switch module 20 and the battery pack 10. The external power supply can directly charge the battery pack 10 through the switch module 20;

[0039] The battery pack 10 may be composed of 4 lithium batteries connected in series. Lithium-ion batteries have begun to be used in 12V starting batteries for automobiles, gradually replacing traditional 12V lead-acid batteries. In actual application, if the ambient temperature is relatively low, the charging capacity of lithium-ion batteries will drop rapidly in a low temperature (less than 0°C) environment. At this time, if a large current is used to charge the battery, lithium deposition may occur in the battery, resulting in an irreversible decrease in the capacity of the battery cell. Long-term lithium deposition may cause internal short circuits in the battery cell, causing thermal runaway of the battery, and resulting in safety accidents such as battery fire. For example, the rated charging current of the on-board DC / DC direct current (DC) charger 3 when charging the battery pack 1 may be 2A. The on-board DC / DC charger 3 also supplies power to the on-board 12V load 2 while charging the battery pack 1. If the on-board 12V load 2 experiences load fluctuations during the charging process, the charging current will fluctuate. For example, if the on-board 12V load 2 is suddenly unloaded, the charging current may become 2.1A, resulting in the problem of excessive charging current. Usually, in this case, the control module 40 sends a request to reduce the charging current to the vehicle-mounted DC / DC charger 3 through the communication module 50. Due to the control cycle problem (generally tens to hundreds of milliseconds), the battery pack 1 may still be overcharged before the adjustment is completed.

[0040] If the control module 40 detects that the fluctuation of the charging current in the status information exceeds a preset threshold, especially in a low temperature environment, the control module 40 can disconnect the electrical connection between the control switch module 20 and the battery pack 10, and connect the electrical connection between the control current limiting module 30 and the battery pack 10. Charging the battery pack 10 through the current limiting module 30 can reduce the occurrence of lithium deposition in the battery pack 10 due to overcharging current, and reduce the possibility of internal short circuit of the battery cell due to long-term lithium deposition, thereby improving the safety of the battery pack 1.

[0041] The battery pack 1 may further include an information acquisition module 60 , which is connected in series with the battery pack 10 , and the control module 40 obtains status information of the battery pack 10 through the information acquisition module 60 .

[0042] The information acquisition module 60 can obtain the current information, voltage information and cell temperature information of the battery pack 10. The control module 40 can obtain the status information of the battery pack 10 through the information acquisition module 60 to reduce the situation of 12V bus power failure. For example: if the charging capacity requested by the battery pack 10 is small, and the battery pack 10 happens to be in a power-deficient state, if the on-board 12V load 2 suddenly increases at this time, the battery pack 10 cannot provide sufficient discharge capacity, and there may be a risk of the 12V bus voltage being too low, causing the 12V bus power failure. Based on the status information, when the on-board DC / DC charger 3 charges the battery pack 1, the control module 40 controls the current limiting module 30 to charge the battery pack 10 with a small current, thereby reducing the situation of overcharging the battery pack 10. At the same time, there is no need to limit the output current of the on-board DC / DC charger 3, which can reduce the problem of the on-board DC / DC charger 3 in the current limiting state due to the large fluctuation of the on-board 12V load 2.

[0043] Optionally, the information acquisition module 60 may include a current information acquisition unit, a voltage information acquisition unit, and a temperature information acquisition unit;

[0044] The current information acquisition unit is connected in series with the battery pack 10, and the control module 40 obtains the current state information of the battery pack 10 through the current information acquisition unit;

[0045] The voltage information acquisition unit is connected in series with the battery pack 10, and the control module 40 obtains the voltage status information of the battery pack 10 through the voltage information acquisition unit;

[0046] The temperature information acquisition unit is connected in series with the battery pack 10 , and the control module 40 obtains the temperature status information of the battery pack 10 through the temperature information acquisition unit.

[0047] The current information acquisition unit may be directly connected in series in the charging / discharging circuit, and is connected in series with the battery pack 10. The control module 40 obtains the current state information of the battery pack 10 through the current information acquisition unit to determine whether the fluctuation of the charging current exceeds a preset threshold value, as well as other state information of the current; the voltage information acquisition unit is provided in the information acquisition module 60, and the information acquisition module 60 is connected in series with the battery pack 10. The control module 40 obtains the total voltage and the cell voltage of the battery pack 10 through the voltage information acquisition unit to determine the capacity of the battery pack 10, thereby determining whether it is necessary to send a charging request to the external power supply through the communication module 50 to determine the time to charge the battery pack 10; The temperature information acquisition unit is arranged in the information acquisition module 60, and the information acquisition module 60 is connected in series with the battery pack 10. The control module 40 obtains the cell temperature of the battery pack 10 through the temperature information acquisition unit. In a low temperature environment (below zero degrees Celsius), the switch module 20 and the current limiting module 30 are controlled in advance through the control module 40, so that when the on-board DC / DC charger 3 charges the battery pack 1 in a low temperature environment, the charging current passes through the current limiting effect of the current limiting module 30, thereby improving the stability of the charging current when charging the battery pack 10, reducing the overcharging current due to current fluctuations, and further reducing the thermal runaway of the battery pack 10, thereby improving the safety of the battery pack 1.

[0048] The information collection module 60 may include a cell balancing unit to further monitor the status information of the battery pack 10 and improve the stability of the battery pack 10 .

[0049] Optionally, the current limiting module 30 is provided with a current limiting driving circuit, and the control module 40 is electrically connected to the current limiting driving circuit;

[0050] The current limiting module 30 includes an energy storage inductor 301, a first switch tube 302 and a second switch tube 303, wherein a first end of the first switch tube 302 is connected to a first end of the energy storage inductor 301, a second end of the first switch tube 302 is connected to a first interface of the current limiting drive circuit, a first end of the second switch tube 303 is connected to a first end of the energy storage inductor 301, a second end of the second switch tube 303 is connected to a second interface of the current limiting drive circuit, and a second end of the energy storage inductor 301 is connected to the battery pack 10;

[0051] The control module 40 controls the on-time of the first switch tube 302 and the second switch tube 303 by adjusting the signals of the first interface and the second interface of the current limiting drive circuit. When the first switch tube 302 is turned on, the second switch tube 303 is turned off, and the energy storage inductor 301 stores energy; when the first switch tube 302 is turned off, the second switch tube 303 is turned on, and the energy storage inductor 301 releases energy.

[0052] In this embodiment, if Figure 1As shown, a DC / DC current limiting module 30 may be connected in parallel with the switch module 20 on the high side of the positive electrode side of the 12V battery pack 1. When the battery pack 10 needs to be charged with current limiting, the charging current is limited by the current limiting module 30. The current limiting drive circuit in the current limiting module 30 may adopt a current closed-loop buck conversion circuit (BUCK control circuit). The first switch tube 302 and the second switch tube 303 may use a metal-oxide-semiconductor field-effect transistor (MOSFET for short). When the first switch tube 302 is turned on, the second switch tube 303 is turned off. When the first switch tube 302 is turned off, the second switch tube 303 is turned on, and its function is equivalent to a rectifier diode.

[0053] The second end of the first switch tube 302 can be connected to the high side (HS) of the first interface of the current limiting drive circuit, and the second end of the second switch tube 303 can be connected to the low side (LS) of the second interface of the current limiting drive circuit; the control module 40 is provided with a pulse width modulation (PWM) interface, and the current limiting drive circuit can be an integrated circuit (IC) of the BUCK power converter. The current limiting drive circuit of the current limiting module 30 is controlled by the PWM signal output by the control module 40;

[0054] The control module 40 adjusts the duty cycle of the PWM signal based on the current signal obtained by the information acquisition module 60, thereby changing the HS and LS control signals in the current limiting drive circuit of the DC / DC current limiting module 30, and further changing the on and off time of the first switch tube 302 to perform current limiting.

[0055] The current limiting module 30 may further include an input capacitor 304 and an output capacitor 305. The input capacitor 304 is used to filter the current input to the current limiting module 30, and the output capacitor 305 is used to filter the current output by the current limiting module 30. One end of the input capacitor 304 is grounded, and the other end is connected to one side of the circuit of the input current limiting module 30. One end of the output capacitor 305 is grounded, and the other end is connected to one side of the circuit output by the current limiting module 30 to filter the current and improve the stability of the current.

[0056] The current limiting module 30 may further include an anti-reverse connection switch tube 306, which is connected in series with the first switch tube 302. When the first switch tube 302 is turned on, the current passes through the anti-reverse connection switch tube 306, the first switch tube 302 and the energy storage inductor 301 in sequence, so as to reduce the damage to the battery pack 10 caused by the reverse connection of the positive and negative poles of the current limiting module 30 to the circuit, thereby improving the safety of the battery pack 1.

[0057] When the first switch tube 302 is turned on, the current flows from Figure 1 The 12V+ in the circuit passes through the anti-reverse connection switch tube 306, the first switch tube 302, the energy storage inductor 301, the battery pack 10, the information acquisition module 60 in sequence, and then returns to the 12V-;

[0058] When the first switch tube 302 is turned off, the energy stored in the energy storage inductor 301 is filtered by the output capacitor 305 and then charges the battery pack 10 through the second switch tube 303. That is, the charging current at this time flows out of the energy storage inductor 301, passes through the battery pack 10, the information acquisition module 60, 12V-, the second switch tube 303 in sequence, and returns to the energy storage inductor 301;

[0059] When the DC / DC current limiting charging is performed, the control module 40 monitors the status information of the battery pack 10 through the information acquisition module 60, and disconnects the electrical connection between the switch module 20 and the battery pack 10 when the fluctuation of the charging current exceeds the preset threshold, and controls the electrical connection between the current limiting module 30 and the battery pack 10 to be connected, and requests charging commands and data from the on-board DC / DC charger 3 through the communication module 50. The charging current of the battery pack 10 flows out from the positive electrode of the on-board DC / DC charger 3, passes through the 12V+ terminal of the battery pack 1, the DC / DC current limiting module 30, flows into the battery pack 10, and then passes through the information acquisition module 60 and the 12V- terminal of the battery pack 1, and finally flows back to the negative electrode of the on-board DC / DC charger 3. In this process, the control module 40 monitors the battery's single cell voltage, temperature, current and other information status in real time through the information acquisition module 60. If a fault occurs, the control module 40 can turn off the DC / DC current limiting module 30 to avoid battery overcharge thermal runaway or other safety faults. In this way, the charging current is limited by the current limiting module 30 , thereby improving the safety of the battery pack 1 .

[0060] Optionally, the switch module 20 is provided with a charging drive circuit and a discharging drive circuit, and the switch module 20 includes a first charging switch tube 201, a second charging switch tube 202, a first discharging switch tube 203 and a second discharging switch tube 204;

[0061] The first charging switch tube 201 and the first discharging switch tube 203 are connected in series and then connected in parallel with the second charging switch tube 202 and the second discharging switch tube 204. The first charging switch tube 201 and the second charging switch tube 202 are connected to the charging drive circuit, and the first discharging switch tube 203 and the second discharging switch tube 204 are connected to the discharging drive circuit. The discharging drive circuit and the charging drive circuit are respectively connected to the control module 40;

[0062] When charging the battery pack 10, the control module 40 controls the start and stop of the charging state through the charging drive circuit;

[0063] When the battery pack 10 is discharging, the control module 40 controls the start and stop of the discharging state through the discharge driving circuit.

[0064] In this embodiment, the first charging switch tube 201, the second charging switch tube 202, the first discharge switch tube 203 and the second discharge switch tube 204 can all be MOSFET switches, and a high-side connection method can be adopted, that is, the MOSFET switch is connected to the positive electrode of the battery pack 10. The MOSFET switch module 20 can be composed of two MOSFET switch branches connected in parallel and a drive circuit, wherein one MOSFET switch branch can be composed of the first charging switch tube 201 and the first discharge switch tube 203 connected in series, and the other MOSFET switch branch can be composed of the second charging switch tube 202 and the second discharge switch tube 204 connected in series;

[0065] The switch module 20 can reduce the technical difficulties of MOSFET on-load diagnosis by adopting two branches in parallel, and reduce the impact on the normal charging and discharging functions of the battery pack 1. During the discharge process of the battery pack 1, the voltage of the battery pack 1 is output to the 12V load terminal through the MOSFET switch module 20; during the charging process, if the battery pack 1 does not need to start the DC / DC current limiting function, the charging current also flows into the battery pack 1 through the MOSFET switch module 20.

[0066] Specifically, Figure 1As shown, during discharge, the control module 40 monitors the status information of the battery pack 10 through the information acquisition module 60, controls the DC / DC current limiting module 30 not to work, and closes the MOSFET switch module 20. The current of the battery pack 1 flows out from the positive electrode BAT+ of the battery pack 10, passes through the MOSFET switch module 20 and the 12V+ terminal of the battery pack 1, flows into the vehicle-mounted 12V load 2, and then returns to the 12V- terminal of the battery pack 1, passes through the information acquisition module 60, and finally flows back to the negative electrode BAT- of the battery pack 10. In this process, the control module 40 monitors the single cell voltage, temperature, current and other information status of the battery pack 10 in real time. If a fault occurs, the control module 40 can turn off the discharge drive circuit of the MOSFET switch module 20, thereby disconnecting the discharge MOSFET switch (the first discharge switch tube 203 and the second discharge switch tube 204), and then the battery pack 10 will be disconnected from the load 2 discharge circuit to avoid battery thermal runaway or other safety faults. During this discharge process, the control module 40 will also monitor the fault status of the MOSFET switch device in real time. When the current of load 2 is less than the set current value I, the control module 40 starts the MOSFET online diagnosis function. The control module 40 disconnects one of the MOSFET discharge MOS switch branches by controlling the MOSFET discharge drive circuit. The control module 40 detects the voltage of the branch and can easily obtain the MOSFET switch state of the branch. Similarly, the MOSFET switch state of another branch can be determined. In this diagnostic process, load 2 does not need to be disconnected, and the function of load diagnosis is realized. The convenience of the battery pack 1 is improved.

[0067] During charging, the control module 40 determines whether the battery pack 1 needs to start the DC / DC current limiting module 30 based on the current temperature, voltage and other information of the battery pack 1. If the current charging condition of the battery pack 10 is good and there is no need to start the current limiting module 30, the battery pack 1 will be charged directly through the MOSFET switch module 20, that is, the general charging process. This embodiment can be divided into a general charging process and a DC / DC current limiting charging process;

[0068] The general charging process control method is similar to the discharge process, which can be the reverse process of the discharge process. During charging, the control module 40 monitors the status information of the battery pack 10 through the information acquisition module 60, closes the MOSFET switch module 20, and requests commands and data from the on-board DC / DC charger 3 through the communication module 50. The current of the battery pack 1 flows out from the positive electrode of the on-board DC / DC charger 3, passes through the 12V+ terminal of the battery pack 1, the MOSFET switch module 20, flows into the battery pack 10, and then passes through the information acquisition module 60 and the 12V- terminal of the battery pack 1, and finally flows back to the negative electrode of the on-board DC / DC charger 3. In this process, the control module 40 can monitor the single cell voltage, temperature, current and other information status of the battery pack 10 in real time. If a fault occurs, the control module 40 can turn off the charging drive circuit of the MOSFET switch module 20, thereby disconnecting the charging MOSFET switch (the first charging switch tube 201, the second charging switch tube 202), and then the battery pack 10 will be disconnected from the charging circuit to avoid battery overcharge thermal runaway or other safety faults. During the charging process, the control module 40 can also monitor the fault status of the MOSFET switch device in real time. When the current of the load 2 is less than the set current value I, the control module 40 starts the MOSFET online diagnosis function. The control module 40 controls the MOSFET charging drive circuit to disconnect one of the MOSFET charging MOS switch branches, detects the voltage of the branch, and can easily obtain the MOSFET switch state of the branch. Similarly, the MOSFET switch state of another branch can be determined. In this diagnostic process, the charging circuit of the on-board DC / DC charger 3 does not need to be disconnected, and the function of on-load diagnosis is realized. The convenience of the battery pack 1 is improved.

[0069] During the current limiting charging process, the DC / DC current limiting module 30 can be a BUCK power converter, and a current closed-loop control method can be adopted. The current limiting drive circuit of the DC / DC current limiting module 30 includes: an energy storage inductor 301, an input capacitor 304, an output capacitor 305, a first switch tube 302 (MOSFET main switch tube), an anti-reverse connection switch tube 306, and a second switch tube 303 (synchronous rectification switch tube). When the first switch tube 302 is turned on, the second switch tube 303 is turned off, and when the first switch tube 302 is turned off, the second switch tube 303 is turned on, and its function is equivalent to a rectifier diode. The current limiting drive circuit can be a driver IC of a BUCK power converter, which can be controlled by a PWM signal output by the control module 40. The working principle of the DC / DC current limiting module 30 may be: the control module 40 adjusts the duty cycle of the PWM signal based on the current signal obtained by the information acquisition module 60, thereby changing the HS and LS control signals in the current limiting drive circuit of the DC / DC current limiting module 30, and then changing the on and off time of the first switch tube 302 (MOSFET main switch tube) to limit the current. Figure 1 The 12V+ in the circuit passes through the anti-reverse connection switch tube 306, the first switch tube 302, the energy storage inductor 301, the battery pack 10, and the information acquisition module 60 in sequence, and then returns to 12V-; when the first switch tube 302 is turned off, the energy stored in the energy storage inductor 301 is filtered by the output capacitor 305 and then charges the battery pack 10 through the second switch tube 303, that is, the charging current at this time flows out from the energy storage inductor 301, passes through the battery pack 10, the information acquisition module 60, 12V-, the second switch tube 303 in sequence, and returns to the energy storage inductor 301.

[0070] When performing DC / DC current limiting charging, the control module 40 monitors the status information of the battery pack 10 through the information acquisition module 60, disconnects the charging drive circuit of the MOSFET switch module 20, and requests commands and data from the on-board DC / DC charger 3 through the communication module 50. The current of the battery pack 1 flows out from the positive electrode of the on-board DC / DC charger 3, passes through the 12V+ terminal of the battery pack 1, the DC / DC current limiting module 30, flows into the battery pack 10, and then passes through the information acquisition module 60 and the 12V- terminal of the battery pack 1, and finally flows back to the negative electrode of the on-board DC / DC charger 3. In this process, the control module 40 can monitor the single cell voltage, temperature, current and other information status of the battery pack 10 in real time. If a fault occurs, the control module 40 can turn off the DC / DC current limiting module 30 to reduce the situation where the battery pack 1 is overcharged and overheated, resulting in loss of control or other safety faults.

[0071] The embodiment of the present invention also provides a battery management system, including: Figure 1The battery pack 1 shown is connected to the circuit of the on-board charger 3 and the on-board load 2 of the battery management system.

[0072] It should be noted that the implementation method of the above-mentioned battery pack embodiment is also applicable to the embodiment of the battery management system and can achieve the same technical effect, which will not be repeated here.

[0073] An embodiment of the present invention further provides a vehicle, comprising the above-mentioned battery management system.

[0074] It should be noted that the implementation method of the above-mentioned battery management system embodiment is also applicable to the embodiment of the vehicle and can achieve the same technical effect, which will not be repeated here.

[0075] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the method and device in the embodiment of the present invention is not limited to performing functions in the order discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0076] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A battery pack, characterized in that: include: A battery pack, a switch module, a current limiting module and a control module, wherein the battery pack is electrically connected to the switch module, the current limiting module is connected in parallel to the switch module, and the control module is electrically connected to the switch module and the current limiting module respectively; The battery pack is electrically connected to the external power supply through the switch module, or the battery pack is electrically connected to the external power supply through the current limiting module; The control module is used to disconnect the electrical connection between the switch module and the battery pack, and control the electrical connection between the current limiting module and the battery pack to be connected when the external power supply is charging the battery pack and the fluctuation of the charging current exceeds a preset threshold value; The switch module is provided with a charging drive circuit and a discharging drive circuit, and the switch module includes a first charging switch tube, a second charging switch tube, a first discharging switch tube and a second discharging switch tube; The first charging switch tube and the first discharging switch tube are connected in series and then connected in parallel with the second charging switch tube and the second discharging switch tube, and the first charging switch tube and the second charging switch tube are connected to the charging drive circuit, the first discharging switch tube and the second discharging switch tube are connected to the discharging drive circuit, and the discharging drive circuit and the charging drive circuit are respectively connected to the control module; When the battery pack is charged, the control module controls the start and stop of the charging state through the charging drive circuit, and when the load current is less than the set current value, the control module starts the online diagnosis function of the first charging switch tube and the second charging switch tube; When the battery pack is discharging, the control module controls the start and stop of the discharge state through the discharge drive circuit. When the load current is less than the set current value, the control module starts the online diagnosis function of the first discharge switch tube and the second discharge switch tube.

2. The battery pack according to claim 1, characterized in that: It also includes a communication module, and the control module is used to obtain status information of the battery pack. When the battery pack needs to be charged, a charging request is sent to an external power supply through the communication module, and the switch module or the current limiting module is controlled to charge the battery pack according to the status information.

3. The battery pack according to claim 2, characterized in that: It also includes an information acquisition module, which is connected in series with the battery pack, and the control module obtains the status information of the battery pack through the information acquisition module.

4. The battery pack according to claim 3, characterized in that: The information acquisition module includes a current information acquisition unit, a voltage information acquisition unit and a temperature information acquisition unit; The current information acquisition unit is connected in series with the battery pack, and the control module obtains the current state information of the battery pack through the current information acquisition unit; The voltage information acquisition unit is connected in series with the battery pack, and the control module obtains the voltage status information of the battery pack through the voltage information acquisition unit; The temperature information acquisition unit is connected in series with the battery pack, and the control module obtains the temperature status information of the battery pack through the temperature information acquisition unit.

5. The battery pack according to claim 1, characterized in that: The current limiting module is provided with a current limiting driving circuit, and the control module is electrically connected to the current limiting driving circuit; The current limiting module includes an energy storage inductor, a first switch tube and a second switch tube, wherein the first end of the first switch tube is connected to the first end of the energy storage inductor, the second end of the first switch tube is connected to the first interface of the current limiting drive circuit, the first end of the second switch tube is connected to the first end of the energy storage inductor, the second end of the second switch tube is connected to the second interface of the current limiting drive circuit, and the second end of the energy storage inductor is connected to the battery pack; The control module controls the on-time of the first switch tube and the second switch tube by adjusting the signals of the first interface and the second interface of the current limiting drive circuit, and when the first switch tube is turned on, the second switch tube is turned off, and the energy storage inductor stores energy; when the first switch tube is turned off, the second switch tube is turned on, and the energy storage inductor releases energy.

6. The battery pack according to claim 5, characterized in that: The current limiting module further includes an input capacitor and an output capacitor, wherein the input capacitor is used to filter the current input to the current limiting module, and the output capacitor is used to filter the current output by the current limiting module.

7. The battery pack according to claim 5, characterized in that: The current limiting module also includes an anti-reverse switching tube, which is connected in series with the first switching tube. When the first switching tube is turned on, the current passes through the anti-reverse switching tube, the first switching tube and the energy storage inductor in sequence.

8. A battery management system, characterized in that: Comprising a battery pack as claimed in any one of claims 1 to 7, wherein the battery pack is connected to the circuit of the on-board charger and the on-board load of the battery management system.

9. A vehicle, characterized in that: Comprising the battery management system as claimed in claim 8.

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