Battery management system, anomaly detection method, battery pack and electric equipment

Abstract

The invention discloses a battery management system, an anomaly detection method, a battery pack and electric equipment, the battery management system is arranged in the battery pack, and the battery management system comprises a plurality of first battery management units, a first sampling circuit, a second sampling circuit and a second battery management unit; optical communication links exist among the plurality of first battery management units, and signal interaction is carried out through the optical communication links; the first sampling circuit is used for sampling an optical signal transmitted by an optical communication link and converting the optical signal into an electric signal; the second sampling circuit is used for sampling a monitoring signal in the battery pack; the second battery management unit is used for outputting a state signal representing whether the battery pack is in an abnormal state or not based on the electric signal and the monitoring signal, and the abnormal state comprises at least one of a thermal runaway state and a liquid leakage state. In this way, the state signal representing the abnormity of the battery pack can be accurately output.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery management system, an abnormality detection method, a battery pack and an electrical device. Background Art

[0002] Batteries (such as power batteries) have the advantages of high energy density, rechargeable, safe and environmentally friendly, and are widely used in new energy vehicles, consumer electronics, energy storage systems, etc. However, when the electrochemical energy contained in the battery is in abnormal conditions such as thermal runaway and leakage, it will cause fires, explosions and other accidents that threaten people's life and property safety.

[0003] Therefore, in order to use batteries safely, it is necessary to strictly regulate the safe operating conditions of the battery status. How to accurately and effectively provide safety warnings for abnormal conditions such as battery thermal runaway and leakage has become an urgent problem to be solved. Summary of the invention

[0004] The present application at least provides a battery management system, an abnormality detection method, a battery pack and an electrical device.

[0005] According to a first aspect of the present application, there is provided a battery management system, which is arranged in a battery pack, and includes a plurality of first battery management units, a first sampling circuit, a second sampling circuit and a second battery management unit; an optical communication link exists between the plurality of first battery management units, and signal interaction is performed through the optical communication link; the first sampling circuit is used to sample the optical signal transmitted by the optical communication link and convert it into an electrical signal; the second sampling circuit is used to sample the monitoring signal in the battery pack; wherein the second sampling circuit includes a light intensity detection component, and the monitoring signal corresponds to a light intensity monitoring signal obtained by sampling the light intensity detection component; the second battery management unit is used to output a status signal indicating whether the battery pack is in an abnormal state based on the electrical signal and the monitoring signal, wherein a decreasing trend of the light intensity monitoring signal within a preset time period indicates that the battery pack is in an abnormal state, and the abnormal state includes at least one of a thermal runaway state and a leakage state.

[0006] Therefore, the second battery management unit determines whether the battery pack is in an abnormal state by combining the electrical signal fed back by the first sampling circuit and the monitoring signal fed back by the second sampling circuit, and uses the electrical signal and the monitoring signal as the condition for determining whether the battery pack is in an abnormal state. In other words, the electrical signal and the monitoring signal serve as each other's complementary judgment basis for whether the battery pack is in an abnormal state. This can accurately determine whether the battery pack is in an abnormal state, thereby accurately outputting a status signal characterizing whether the battery pack is in an abnormal state, reducing the possibility of false alarm of battery pack abnormality, and providing more accurate and effective safety warning for battery pack abnormality.

[0007] In addition, when the battery pack is in a state of thermal runaway or leakage, gas, smoke or liquid will be generated in the battery pack, causing light to be scattered, refracted, etc. during propagation, resulting in a reduction in the amount of light reaching the target location, thereby causing the light intensity at the target location to decrease, that is, causing the light intensity monitoring signal sampled by the light intensity detection component at the target location to decrease. If the light intensity monitoring signal sampled by the light intensity detection component at the target location continues to decrease within a preset time, it can be considered that the light intensity monitoring signal indicates that the battery pack is in an abnormal state.

[0008] The second battery management unit is used to output a status signal indicating that the battery pack is in an abnormal state in response to the signal value of the electrical signal sampled within the first time period being less than a preset threshold and the monitoring signal indicating that the battery pack is in an abnormal state.

[0009] Therefore, the battery pack can be considered to be in an abnormal state only when the results determined based on the electrical signal and the monitoring signal respectively point to the battery pack being in an abnormal state. It is possible to accurately determine whether the battery pack is in an abnormal state, thereby reducing the possibility of false alarm of battery pack abnormality and providing more accurate and effective safety warning for battery pack abnormality.

[0010] The second sampling circuit further includes at least one of a sensor and a third battery management unit, and the monitoring signal corresponds to at least one of an environmental monitoring signal sampled by the sensor and a circuit monitoring signal sampled by the third battery management unit.

[0011] Therefore, the second sampling circuit can be flexibly set.

[0012] Among them, the second battery management unit is used to respond to the signal value of the electrical signal sampled within the first time period being less than a preset threshold, the environmental monitoring signal indicating that the battery pack is in an abnormal state, and the existence of a battery cell-related monitoring signal indicating that the battery pack is in an abnormal state, and output a status signal characterizing that the battery pack is in an abnormal state, and the battery cell-related monitoring signal includes a circuit monitoring signal and / or a light intensity monitoring signal.

[0013] Therefore, the battery pack can be considered to be in an abnormal state only when the results determined based on the electrical signal, environmental monitoring signal, and battery cell-related monitoring signal respectively point to the battery pack being in an abnormal state. It can accurately determine whether the battery pack is in an abnormal state, thereby reducing the possibility of false alarm of battery pack abnormality and providing more accurate and effective safety warning for battery pack abnormalities.

[0014] Wherein, the environmental monitoring signal includes at least one of an air pressure signal sampled by an air pressure sensor and a smoke signal sampled by a smoke sensor; the second battery management unit is used to respond to the signal value of the electrical signal sampled within the first time period being less than a preset threshold, the air pressure signal or the smoke signal indicating that the battery pack is in an abnormal state, and the existence of a battery cell-related monitoring signal indicating that the battery pack is in an abnormal state, output a first state signal indicating that the battery pack is in a thermal runaway state; and / or, the environmental monitoring signal includes a leakage signal sampled by a leakage sensor; the second battery management unit is used to respond to the signal value of the electrical signal sampled within the first time period being less than a preset threshold, the leakage signal indicating that the battery pack is in an abnormal state, and the existence of a battery cell-related monitoring signal indicating that the battery pack is in an abnormal state, output a second state signal indicating that the battery pack is in a leakage state.

[0015] Therefore, the battery pack can be considered to be in an abnormal state only when the results determined based on the electrical signal, air pressure signal or smoke signal, and the battery cell-related monitoring signal indicate that the battery pack is in an abnormal state at the same time, and it can accurately determine whether the battery pack is in an abnormal state, thereby reducing the possibility of false alarms of battery pack abnormalities and providing more accurate and effective safety warnings for battery pack abnormalities. The air pressure signal sampled by the air pressure sensor and / or the smoke signal sampled by the smoke sensor indicate that the battery pack is in an abnormal state, which can further determine whether the battery pack is specifically in a thermal runaway abnormal state.

[0016] Among them, the battery cell related monitoring signal includes circuit monitoring data, and the circuit monitoring data includes at least one of the following: the voltage of the battery cell, the battery cell temperature of the battery cell; wherein, the voltage of the battery cell indicates that the battery pack is in an abnormal state, which is characterized by: the voltage is lower than the voltage threshold, and the battery cell temperature of the battery cell indicates that the battery pack is in an abnormal state, which is characterized by at least one of the following: the battery cell temperature is higher than the temperature threshold, and the rate of rise of the battery cell temperature is higher than the rate threshold.

[0017] Therefore, when the battery pack is in a thermal runaway state, the chemical reaction inside the battery cell is accelerated, resulting in a decrease in the impedance inside the battery cell, thereby causing the voltage of the battery cell to drop. When the battery pack is in a leaking state, it means that the electrolyte in the battery cell has leaked out, which will cause the ion conduction inside the battery cell to be blocked, resulting in a decrease in the voltage of the battery cell; in addition, the leaked electrolyte may corrode the positive and negative contacts of the battery cell. This corrosion may destroy the active substances on the surface of the electrode, reduce the reaction activity of the electrode, and thus reduce the voltage of the battery cell. Therefore, if the voltage of the battery cell is lower than the voltage threshold, it can be considered that the voltage of the battery cell indicates that the battery pack is in an abnormal state. When the battery pack is in a thermal runaway state, the temperature of the battery cell of the battery cell will gradually increase, accompanied by the acceleration of the chemical reaction inside the battery cell and the increase in heat generation. When the battery pack is in a leaking state, it means that the electrolyte in the battery cell has leaked out. If the electrolyte reacts with certain materials inside the battery cell of the battery cell, it may release heat, causing the battery cell temperature of the battery cell to rise. In addition, the leakage may cause the electrolyte inside the battery cell of the battery cell to be unevenly distributed, thereby causing an internal short circuit. The short circuit will generate a large amount of heat, causing the battery cell temperature of the battery cell to rise sharply. Therefore, if the battery cell temperature of the battery cell is higher than the temperature threshold and / or the rate of increase of the battery cell temperature of the battery cell is higher than the rate threshold, it can be considered that the battery cell temperature of the battery cell indicates that the battery pack is in an abnormal state.

[0018] Among them, the light intensity detection component includes a light source driving unit and a light intensity detection unit. The light source driving unit is used to emit light, and the light intensity detection unit is used to detect the intensity of the light and obtain a light intensity monitoring signal.

[0019] Therefore, when the battery pack is in a normal state, the light emitted by the light source driving unit will propagate to the light intensity detection unit, and the light intensity detected by the light intensity detection unit is relatively large. When the battery pack is in a thermal runaway or leaking state, gas smoke or liquid will be generated in the battery pack, causing the light to be scattered and refracted during propagation, resulting in a reduction in the light reaching the light intensity detection unit, thereby reducing the light intensity detected by the light intensity detection unit.

[0020] Among them, the light source driving unit and the corresponding light intensity detection unit are respectively arranged on opposite sides of the battery cell in the battery pack; and / or the number of the light intensity detection components is at least one, the detection paths of all the light intensity detection components cover all the battery cells in the battery pack, and the detection path of the light intensity detection component is a detection loop formed between the light source driving unit in the light intensity detection component and the light intensity detection unit; and / or the light source driving unit is a light emitting diode; and / or the light intensity detection unit includes a photoresistor.

[0021] Therefore, by setting the light source driving unit and the corresponding light intensity detection unit on opposite sides of the battery cell in the battery pack, it is possible to directly measure the internal state of the battery cell, accurately reflect the change in light transmittance of the battery cell under abnormal conditions, and improve the detection accuracy; in addition, it is possible to minimize the interference of external environmental factors on light intensity detection and improve the detection accuracy. By setting the detection path of all light intensity detection components to cover all battery cells in the battery pack, it can be ensured that each battery cell is monitored without omissions, which helps to promptly detect any potential abnormal signs and avoid safety hazards caused by incomplete monitoring. The light source driving unit and the light intensity detection unit can be flexibly set.

[0022] A second aspect of the present application provides an abnormality detection method, which includes: obtaining a first signal output by a first sampling circuit and a second signal output by a second sampling circuit; wherein the first signal is an electrical signal converted from an optical signal transmitted by an optical communication link, the optical communication link, the first sampling circuit and the second sampling circuit are all arranged in a battery pack, and the second signal is a monitoring signal in the battery pack; combining the first signal and the second signal, determining whether the battery pack is in an abnormal state; wherein the abnormal state includes at least one of a thermal runaway state and a liquid leakage state.

[0023] A third aspect of the present application provides a battery pack, which includes a battery cell and the above-mentioned battery management system.

[0024] The fourth method of the present application provides an electrical device, which includes a battery pack, which supplies power to the electrical device, and the battery pack is the battery pack mentioned above.

[0025] In the above technical solution, the second battery management unit is used to output a status signal representing whether the battery pack is in an abnormal state based on the electrical signal output by the first sampling circuit and the monitoring signal output by the second sampling circuit. Therefore, the second battery management unit determines whether the battery pack is in an abnormal state by combining the electrical signal fed back by the first sampling circuit and the monitoring signal fed back by the second sampling circuit, and uses the electrical signal and the monitoring signal as a condition for determining whether the battery pack is in an abnormal state. In other words, the electrical signal and the monitoring signal are each other's supplementary basis for determining whether the battery pack is in an abnormal state, which can accurately determine whether the battery pack is in an abnormal state, thereby accurately outputting a status signal representing whether the battery pack is in an abnormal state, reducing the possibility of false alarms of battery pack abnormalities, and providing more accurate and effective safety warnings for battery pack abnormalities.

[0026] In addition, when the battery pack is in a state of thermal runaway or leakage, gas, smoke or liquid will be generated in the battery pack, causing light to be scattered, refracted, etc. during propagation, resulting in a reduction in the amount of light reaching the target location, thereby causing the light intensity at the target location to decrease, that is, causing the light intensity monitoring signal sampled by the light intensity detection component at the target location to decrease. If the light intensity monitoring signal sampled by the light intensity detection component at the target location continues to decrease within a preset time, it can be considered that the light intensity monitoring signal indicates that the battery pack is in an abnormal state. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of an embodiment of a battery management system provided by the present application; Figure 2 It is a structural schematic diagram of an embodiment of a light intensity detection component provided by the present application; Figure 3 It is a flowchart of an embodiment of an abnormality detection method provided by the present application; Figure 4 is a structural schematic diagram of an embodiment of a battery pack provided by the present application; Figure 5 It is a structural schematic diagram of an embodiment of an electrical equipment provided by the present application. DETAILED DESCRIPTION

[0028] The scheme of the embodiment of the present application is described in detail below in conjunction with the drawings of the specification.

[0029] In the following description, for the purpose of explanation rather than limitation, specific details such as specific system structures, interfaces, and technologies are provided to facilitate a thorough understanding of the present application.

[0030] The term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the objects associated before and after are in an "or" relationship. In addition, "many" in this article means two or more than two. In addition, the term "at least one" in this article means any combination of at least two of any one or more of a plurality of, for example, including at least one of A, B, and C, can mean including any one or more elements selected from the set consisting of A, B, and C.

[0031] In order to better understand the present application, the battery management system provided by the present application is described in more detail below with reference to the accompanying drawings and specific embodiments.

[0032] Thermal runaway of a battery pack refers to a phenomenon in which, for some reason, the battery cells in the battery pack generate a large amount of heat in a short period of time, and this heat cannot be dissipated in time, causing the temperature inside the battery pack to rise sharply, and eventually causing the battery pack to overheat, catch fire, or even explode. When the battery pack is in a state of thermal runaway, the chemical reaction inside the battery cells will intensify, generating a large amount of heat and gas, which may include carbon dioxide, carbon monoxide, hydrogen, methane, and other flammable and toxic gases; in addition, the electrolyte and other materials in the battery pack will also decompose at high temperatures, releasing harmful gases and smoke.

[0033] A battery pack is usually composed of multiple battery cells, which contain electrolytes, which are an important component of electrochemical reactions. However, when the battery cells have problems such as poor sealing, cracked shells, and welding defects, the electrolyte will leak out from the battery cells, causing the battery pack to leak. When the battery pack is in a leaking state, the leaked electrolyte may corrode the electronic components and circuits inside the battery pack, causing a short circuit between battery cells or between battery cells and the shell. The short circuit will generate a lot of heat and current, which may cause the battery pack to overheat, swell, or even explode.

[0034] See also Figure 1 , Figure 1 The present application provides a battery management system 10, which is disposed in a battery pack and includes a plurality of first battery management units 11, a first sampling circuit 12, a second sampling circuit 13 and a second battery management unit 14.

[0035] There is an optical communication link 20 between the multiple first battery management units 11, and signal interaction is performed through the optical communication link 20. Optical communication has the advantages of high speed, high bandwidth, and low interference, so the multiple first battery management units 11 can perform real-time and efficient signal interaction through the optical communication link 20. Among them, the number of first battery management units 11 in the battery pack is not limited, and can be specifically set according to actual use needs.

[0036] In one embodiment, one of the first battery management units 11 is a main control unit, and at least one of the first battery management units 11 is a data monitoring module of a battery pack. The main control unit and the data monitoring module can perform real-time and efficient signal interaction through the optical communication link 20, which may involve battery status information interaction (e.g., the data monitoring module is responsible for monitoring the voltage and temperature of the battery cell, etc., and this information is transmitted to the main control unit in real time and efficiently for overall analysis and decision-making), control instruction interaction (e.g., the main control unit determines whether it is necessary to start the equalization circuit for voltage equalization based on the battery cell voltage information uploaded by the data monitoring module. If necessary, the main control unit will send an equalization instruction to the corresponding data monitoring module to adjust the voltage difference between the battery cells), and other information interaction (e.g., during the initialization or maintenance of the battery management system 10, the main control unit may need to send configuration and calibration information to the data monitoring module). The data monitoring modules can perform real-time and efficient signal interaction through the optical communication link 20, which may involve battery status information interaction (for example, the data monitoring modules will transmit the voltage and temperature information of the battery cells they monitor to each other, which helps the entire battery management system 10 to more comprehensively understand the status of each battery cell in the battery pack, thereby performing more precise management and control), control command interaction (for example, in order to maintain voltage balance between battery cells, a data monitoring module may send balancing instructions to other data monitoring modules), and other information interaction (for example, during the initialization or maintenance of the battery management system 10, configuration and calibration information may need to be transmitted between data monitoring modules).

[0037] Of course, in other implementations, all first battery management units 11 may be data monitoring modules of the battery pack, which is not limited here.

[0038] The first sampling circuit 12 is used to sample the optical signal transmitted by the optical communication link 20 and convert it into an electrical signal. When the battery pack is in a normal state, the optical signal can be transmitted according to the optical communication link 20. When the battery pack is in a thermal runaway state, gas or smoke will be generated in the battery pack. The gas or smoke generated in the battery pack will appear in the optical communication link 20, causing the propagation medium of the optical signal to change. Therefore, the optical signal will not be completely transmitted according to the optical communication link 20; then, the optical signal transmitted by the optical communication link 20 will change, so that the electrical signal converted based on the optical signal transmitted by the optical communication link 20 will change. When the battery pack is in a leaking state, the leaked electrolyte will flood multiple first battery management units 11, that is, it will flood the optical communication link 20 between multiple first battery management units 11, so that the propagation medium of the optical signal will change. Therefore, the optical signal will not be completely transmitted according to the optical communication link 20; then, the optical signal transmitted by the optical communication link 20 will change, so that the electrical signal converted based on the optical signal transmitted by the optical communication link 20 will change. Therefore, the optical signal transmitted by the optical communication link 20 is converted into an electrical signal to determine whether the battery pack is in an abnormal state. Therefore, the optical signal transmitted by the optical communication link 20 is sampled and converted into an electrical signal for the second battery management unit 14 to determine whether the battery pack is in an abnormal state.

[0039] The second sampling circuit 13 is used to sample the monitoring signal in the battery pack. When the battery pack is in a normal state, the monitoring signal in the battery pack must be normal. If the monitoring signal in the battery pack is abnormal, it means that the battery pack is in an abnormal state. Therefore, the monitoring signal in the battery pack can be used to determine whether the battery pack is in an abnormal state. Therefore, by sampling the monitoring signal in the battery pack, the second battery management unit 14 can determine whether the battery pack is in an abnormal state.

[0040] The second battery management unit 14 is used to output a status signal indicating whether the battery pack is in an abnormal state based on the electrical signal and the monitoring signal, wherein the abnormal state includes at least one of a thermal runaway state and a leakage state. Whether the battery pack is in an abnormal state is determined by combining the electrical signal fed back by the first sampling circuit 12 and the monitoring signal fed back by the second sampling circuit 13, and the electrical signal and the monitoring signal are used as a condition for determining whether the battery pack is in an abnormal state. In other words, the electrical signal and the monitoring signal are each other's supplementary basis for determining whether the battery pack is in an abnormal state, which can accurately determine whether the battery pack is in an abnormal state, thereby accurately outputting a status signal indicating whether the battery pack is in an abnormal state, reducing the possibility of false alarms of battery pack abnormalities, and providing more accurate and effective safety warnings for battery pack abnormalities.

[0041] Among them, Figure 2 As shown, Figure 2It is a structural diagram of an embodiment of a light intensity detection component provided by the present application. The second sampling circuit 13 includes a light intensity detection component 131. The monitoring signal corresponds to a light intensity monitoring signal sampled by the light intensity detection component 131. The light intensity monitoring signal is in a decreasing trend within a preset time period, indicating that the battery pack is in an abnormal state. In other words, within the preset time period, if the light intensity monitoring signal sampled by the light intensity detection component 131 continues to decrease, it can be considered that the result indicated by the light intensity monitoring signal is that the battery pack is in an abnormal state. Among them, the size of the preset time period is not limited, and can be specifically set according to actual use needs; for example, the preset time period is 5 minutes, 10 minutes, etc.

[0042] When the battery pack is in a state of thermal runaway or leakage, gas, smoke or liquid will be generated in the battery pack, causing light to be scattered, refracted, etc. during propagation, resulting in a reduction in the amount of light reaching the target position, thereby reducing the light intensity at the target position, that is, causing the light intensity monitoring signal sampled at the target position by the light intensity detection component 131 to decrease. If the light intensity monitoring signal sampled at the target position by the light intensity detection component 131 continues to decrease within a preset time, it can be considered that the light intensity monitoring signal indicates that the battery pack is in an abnormal state.

[0043] In one embodiment, the second battery management unit 14 is the main control unit of the battery management system 10. The main control unit plays a core role in the battery management system 10 and has functional characteristics such as data processing, fault alarm, SOC estimation, and charge and discharge management. Therefore, using the main control unit as the second battery management unit 14 can determine in real time and reliably whether the battery pack is in an abnormal state; in addition, the main control unit has high reliability and stability, and can ensure normal operation in harsh environments. Of course, in other embodiments, the second battery management unit 14 can also be an abnormality judgment unit additionally provided in addition to the main control unit, which is not limited here.

[0044] In one embodiment, the second battery management unit 14 is used to output a state signal indicating that the battery pack is in an abnormal state in response to the signal value of the electrical signal sampled within the first time period being less than a preset threshold value and the monitoring signal indicating that the battery pack is in an abnormal state. That is to say, the battery pack can be considered to be in an abnormal state only when the results determined based on the electrical signal and the monitoring signal respectively indicate that the battery pack is in an abnormal state, and it can be accurately determined whether the battery pack is in an abnormal state, thereby reducing the possibility of false alarms of battery pack abnormalities and providing more accurate and effective safety warnings for battery pack abnormalities.

[0045] It should be noted that when the battery pack is determined to be in an abnormal state through a single judgment condition of the signal value of the electrical signal or the monitoring signal sampled within the first time period, the determination result may be accidental and may be incorrect; and when the results determined based on all judgment conditions point to the battery pack being in an abnormal state, then the battery pack must be in an abnormal state.

[0046] In addition, when the battery pack is in a thermal runaway state, gas or smoke will be generated in the battery pack. The gas or smoke generated in the battery pack will appear in the optical communication link 20, causing the propagation medium of the optical signal to change. Therefore, the optical signal will not be completely transmitted according to the optical communication link 20; then, the optical signal transmitted by the optical communication link 20 will be weakened, so that the signal value of the electrical signal converted based on the optical signal transmitted by the optical communication link 20 will be reduced. When the battery pack is in a leaking state, the leaked electrolyte will flood the multiple first battery management units 11, that is, it will flood the optical communication links 20 between the multiple first battery management units 11, causing the propagation medium of the optical signal to change. Therefore, the optical signal will not be completely transmitted according to the optical communication link 20; then, the optical signal transmitted by the optical communication link 20 will be weakened, so that the signal value of the electrical signal converted based on the optical signal transmitted by the optical communication link 20 will be reduced. Therefore, when the signal value of the electrical signal sampled within the first time length is less than the preset threshold, it can be considered that the battery pack is in an abnormal state.

[0047] Furthermore, in special circumstances, the optical signal transmitted by the sampled optical communication link 20 is very weak and cannot be converted into an electrical signal, and the second battery management unit 14 cannot obtain the electrical signal from the first sampling circuit 12; when the second battery management unit 14 cannot obtain the electrical signal from the first sampling circuit 12, the signal value of the electrical signal at this time can be assumed to be 0.

[0048] The first duration and the preset threshold are not limited and can be set according to actual use needs. For example, the first duration is 1 minute, 5 minutes, 10 minutes, 15 minutes, etc.

[0049] In a specific embodiment, the second sampling circuit 13 also includes at least one of a sensor (not shown in the figure) and a third battery management unit (not shown in the figure), and the monitoring signal corresponds to at least one of an environmental monitoring signal sampled by the sensor and a circuit monitoring signal sampled by the third battery management unit.

[0050] When the battery pack is in a thermal runaway state, gas or smoke will be generated in the battery pack. Then, the environmental state in the battery pack will change, and the environmental monitoring signal of the battery pack sampled by the sensor will also change. Therefore, based on the environmental monitoring signal sampled by the sensor, it is possible to determine whether the battery pack is in an abnormal state. Therefore, the environmental monitoring signal sampled by the sampling sensor is used for the second battery management unit 14 to determine whether the battery pack is in an abnormal state. When the battery is in a leakage state, there will be leaked electrolyte in the battery pack. Then, the environmental state in the battery pack will change, and the environmental monitoring signal of the battery pack sampled by the sensor will change. Therefore, the environmental monitoring signal sampled by the sampling sensor is used for the second battery management unit 14 to determine whether the battery pack is in an abnormal state.

[0051] When the battery pack is in a normal state, the circuit monitoring signal in the battery pack must be normal. If the circuit monitoring signal in the battery pack is abnormal, it means that the battery pack is in an abnormal state. Therefore, the circuit monitoring signal in the battery pack can be used to determine whether the battery pack is in an abnormal state. Therefore, the circuit monitoring signal sampled by the third battery management unit is sampled so that the second battery management unit 14 can determine whether the battery pack is in an abnormal state.

[0052] In a specific implementation, the third battery management unit is a data monitoring module.

[0053] In a specific embodiment, the second battery management unit is used to respond to the signal value of the electrical signal sampled within the first time period being less than a preset threshold value, the environmental monitoring signal indicating that the battery pack is in an abnormal state, and the presence of a battery cell-related monitoring signal indicating that the battery pack is in an abnormal state, output a status signal characterizing that the battery pack is in an abnormal state, and the battery cell-related monitoring signal includes a circuit monitoring signal and / or a light intensity monitoring signal.

[0054] That is to say, the battery pack can be considered to be in an abnormal state only when the results determined based on the electrical signal, environmental monitoring signal, and battery cell-related monitoring signal respectively point to the battery pack being in an abnormal state. It can accurately determine whether the battery pack is in an abnormal state, thereby reducing the possibility of false alarm of battery pack abnormality and providing more accurate and effective safety warnings for battery pack abnormalities.

[0055] It should be noted that when one of the circuit monitoring signal and the light intensity monitoring signal indicates that the battery pack is in an abnormal state, it can be considered that there is a cell-related monitoring signal indicating that the battery pack is in an abnormal state. For example, when the battery pack is in an abnormal state, the light intensity monitoring signal sampled by the light intensity detection component 131 continues to decrease, and the result indicated by the light intensity monitoring signal is that the battery pack is in an abnormal state; but the current abnormal state of the battery pack does not temporarily affect the voltage of the battery cell, the cell temperature of the battery cell, etc., so the result indicated by the circuit monitoring signal is that the battery pack is in a normal state; and because the result indicated by the light intensity monitoring signal is that the battery pack is in an abnormal state, there is a cell-related monitoring signal indicating that the battery pack is in an abnormal state.

[0056] In a specific embodiment, the environmental monitoring signal includes at least one of an air pressure signal sampled by an air pressure sensor and a smoke signal sampled by a smoke sensor: the second battery management unit 14 is used to respond to the signal value of the electrical signal sampled within the first time period being less than a preset threshold, the air pressure signal or the smoke signal indicating that the battery pack is in an abnormal state, and there is a cell-related monitoring signal indicating that the battery pack is in an abnormal state, and output a first state signal indicating that the battery pack is in a thermal runaway state.

[0057] When the battery pack is in a state of thermal runaway, gas may be generated in the battery pack, and the air pressure in the battery pack will change; the air pressure signal sampled by the air pressure sensor can reflect the air pressure in the battery pack, so the air pressure signal sampled by the air pressure sensor can determine whether the battery pack is in a state of thermal runaway. When the battery pack is in a state of thermal runaway, smoke may also be generated in the battery pack; the smoke signal sampled by the smoke sensor can reflect the smoke in the battery pack, so the smoke signal sampled by the smoke sensor can determine whether the battery pack is in a state of thermal runaway.

[0058] The battery pack can be considered to be in an abnormal state only when the results determined based on the electrical signal, air pressure signal or smoke signal, and the battery cell-related monitoring signal all indicate that the battery pack is in an abnormal state. This can accurately determine whether the battery pack is in an abnormal state, thereby reducing the possibility of false alarms of battery pack abnormalities and providing more accurate and effective safety warnings for battery pack abnormalities. The air pressure signal sampled by the air pressure sensor and / or the smoke signal sampled by the smoke sensor indicate that the battery pack is in an abnormal state, which can further determine whether the battery pack is in a thermal runaway abnormal state.

[0059] In a specific embodiment, the air pressure signal sampled by the air pressure sensor is the air pressure magnitude, and when the air pressure rise rate in the battery pack is greater than or equal to the air pressure rate threshold, it indicates that the battery pack is in an abnormal state. The air pressure rate threshold is not limited and can be specifically set according to actual use needs.

[0060] In a specific embodiment, the smoke signal sampled by the smoke sensor is the smoke content, and when the smoke content in the battery pack is greater than or equal to the smoke threshold, it indicates that the battery pack is in an abnormal state. The smoke threshold is not limited and can be specifically set according to actual use needs.

[0061] In a specific embodiment, the environmental monitoring signal includes a leakage signal sampled by a leakage sensor; the second battery management unit 14 is used to respond to the signal value of the electrical signal sampled within the first time period being less than a preset threshold, the leakage signal indicating that the battery pack is in an abnormal state, and the presence of a cell-related monitoring signal indicating that the battery pack is in an abnormal state, outputting a second state signal indicating that the battery pack is in a leakage state.

[0062] When the battery pack is in a leakage state, there is leaked electrolyte in the battery pack; the leakage signal sampled by the leakage sensor can reflect the leakage situation in the battery pack. Therefore, the leakage signal sampled by the leakage sensor can determine whether the battery pack is in a leakage state.

[0063] The battery pack can only be considered to be in an abnormal state when the results determined based on the electrical signal, leakage signal, and battery cell-related monitoring signal all indicate that the battery pack is in an abnormal state. This can accurately determine whether the battery pack is in an abnormal state, thereby reducing the possibility of false alarms of battery pack abnormalities and providing more accurate and effective safety warnings for battery pack abnormalities. The leakage signal obtained by sampling the leakage sensor indicates that the battery pack is in an abnormal state, which can further determine whether the battery pack is in a specific abnormal leakage state.

[0064] In a specific embodiment, the leakage sensor includes two probes, and the leakage signal sampled by the leakage sensor is the impedance between the two probes. If there is no liquid between the two probes (completely air), then the impedance between the two probes is very large; if there is liquid between the two probes, then the impedance between the two probes becomes smaller; therefore, when the impedance between the two probes is less than or equal to the impedance threshold, it indicates that the battery pack is in an abnormal state. Among them, the size of the impedance threshold is not limited, and can be specifically set according to actual use needs.

[0065] In a specific embodiment, the cell-related monitoring signal includes circuit monitoring data, and the circuit monitoring data includes at least one of the following: the voltage of the battery cell, the cell temperature of the battery cell; wherein the voltage of the battery cell indicates that the battery pack is in an abnormal state, characterized by: the voltage is lower than the voltage threshold, and the cell temperature of the battery cell indicates that the battery pack is in an abnormal state, characterized by at least one of the following: the cell temperature is higher than the temperature threshold, and the rate of increase of the cell temperature is higher than the rate threshold. That is to say, if the voltage of the battery cell sampled by the third battery management unit is lower than the voltage threshold, it can be considered that the result of the voltage indication of the battery cell is that the battery pack is in an abnormal state. When the cell temperature of the battery cell sampled by the third battery management unit is higher than the temperature threshold or the rate of increase of the cell temperature is higher than the rate threshold, it can be considered that the result of the cell temperature indication of the battery cell is that the battery pack is in an abnormal state. Among them, the size of the temperature threshold, the temperature threshold, and the rate threshold is not performed, and can be specifically set according to actual use needs.

[0066] When the battery pack is in a normal state, the voltage of the battery cell usually remains unchanged at the platform voltage. When the battery pack is in a thermal runaway state, the chemical reaction inside the battery cell is accelerated, resulting in a decrease in the impedance inside the battery cell, which in turn causes the voltage of the battery cell to drop. When the battery pack is in a leaking state, it means that the electrolyte in the battery cell has leaked out, which will cause the ion conduction inside the battery cell to be blocked, resulting in a decrease in the voltage of the battery cell; in addition, the leaked electrolyte may corrode the positive and negative contacts of the battery cell. This corrosion may destroy the active substances on the surface of the electrode, reduce the reaction activity of the electrode, and thus reduce the voltage of the battery cell. Therefore, if the voltage of the battery cell is lower than the voltage threshold, it can be considered that the voltage of the battery cell indicates that the battery pack is in an abnormal state.

[0067] When the battery pack is in a state of thermal runaway, the cell temperature of the battery cell will gradually increase, accompanied by the acceleration of the chemical reaction inside the cell and the increase of heat generation. When the battery pack is in a state of leakage, it means that the electrolyte in the battery cell has leaked out. If the electrolyte reacts with certain materials inside the cell of the battery cell, it may release heat, causing the cell temperature of the battery cell to rise. In addition, leakage may cause uneven distribution of electrolyte inside the cell of the battery cell, thereby causing an internal short circuit. The short circuit will generate a large amount of heat, causing the cell temperature of the battery cell to rise sharply. Therefore, if the cell temperature of the battery cell is higher than the temperature threshold and / or the rate of increase of the cell temperature of the battery cell is higher than the rate threshold, it can be considered that the cell temperature of the battery cell indicates that the battery pack is in an abnormal state.

[0068] In a specific embodiment, the cell-related monitoring signal includes circuit monitoring data, and the circuit monitoring data also includes the disconnection status of the sampling line connected to the battery cell, wherein the disconnection status of the sampling line connected to the battery cell indicates that the battery pack is in an abnormal state, which is characterized as: the sampling line is in a disconnected state. It should be noted that when the circuit monitoring data sampled by the third battery management unit is 0 or the third battery management unit cannot sample the circuit monitoring data, it can be considered that the sampling line is in a disconnected state.

[0069] When the battery pack is in a thermal runaway state, the temperature inside the battery pack rises. When the temperature inside the battery pack reaches a certain level, the sampling line connecting the third battery management unit and the battery cell may be burned out, resulting in the third battery management unit being unable to sample circuit monitoring data or causing the circuit monitoring data sampled by the third battery management unit to be 0. Therefore, if the sampling line connected to the battery cell is in a disconnected state, it can be considered that the disconnected state of the sampling line connected to the battery cell indicates that the battery pack is in an abnormal state.

[0070] In a specific embodiment, the light intensity detection component 131 includes a light source driving unit 1311 and a light intensity detection unit 1312. The light source driving unit 1311 is used to emit light, and the light intensity detection unit 1312 is used to detect the intensity of the light to obtain a light intensity monitoring signal.

[0071] When the battery pack is in a normal state, the light emitted by the light source driving unit 1311 will propagate to the light intensity detection unit 1312, and the light intensity detected by the light intensity detection unit 1312 is relatively large. When the battery pack is in a thermal runaway or leaking state, gas smoke or liquid will be generated in the battery pack, causing the light to be scattered, refracted, etc. during propagation, resulting in a reduction in the light reaching the light intensity detection unit 1312, thereby reducing the light intensity detected by the light intensity detection unit 1312.

[0072] In a specific embodiment, the light source driving unit 1311 and the corresponding light intensity detection unit 1312 (such as Figure 2 As shown, the light source driving unit 1 and the light intensity detection unit 1 correspond to each other, and the light source driving unit 2 and the light intensity detection unit 2 are respectively arranged on opposite sides of the battery cell in the battery pack. The light source driving unit 1311 and the corresponding light intensity detection unit 1312 are respectively arranged on opposite sides of the battery cell in the battery pack, so as to realize direct measurement of the internal state of the battery cell, accurately reflect the change of light transmittance of the battery cell under abnormal state, and improve the detection accuracy; in addition, the interference of external environmental factors on light intensity detection can be minimized to improve the detection accuracy.

[0073] In other specific implementations, the light source driving unit 1311 and the corresponding light intensity detection unit 1312 may also be disposed on two adjacent sides of a battery cell in the battery pack, which is not limited here.

[0074] In a specific embodiment, the number of light intensity detection components 131 is at least one, and the detection paths of all light intensity detection components 131 cover all battery cells in the battery pack. The detection paths of the light intensity detection components 131 are detection loops formed between the light source driving unit 1311 and the light intensity detection unit 1312 in the light intensity detection components 131. By setting the detection paths of all light intensity detection components 131 to cover all battery cells in the battery pack, it can be ensured that each battery cell is monitored without omission, which helps to promptly discover any potential abnormal signs and avoid safety hazards caused by incomplete monitoring.

[0075] The number of the light intensity detection components 131 is not limited and can be set according to actual use requirements. For example, the number of the light intensity detection components 131 is 1, 2, 5, etc.

[0076] In a specific embodiment, the light source driving unit 1311 is a light emitting diode. A light emitting diode is a semiconductor electronic component that can convert electrical energy into light energy. Its core part is a chip composed of a P-type semiconductor and an N-type semiconductor, and there is a transition layer between the P-type semiconductor and the N-type semiconductor. When the light emitting diode is in a forward working state, the current flows from the anode of the light emitting diode to the cathode, and the semiconductor crystal will emit light of different colors from ultraviolet to infrared. In addition, the light emitting diode is a cold light source, which is more energy-saving. The light emitting diode is a solid cold light source, and there is no loose part in the lamp body, so there are no disadvantages such as easy burning of the filament light and light decay. The light emitting diode has a fast response speed and is suitable for high-speed optical communication.

[0077] In a specific implementation, the light intensity detection unit 1312 includes a photoresistor. The photoresistor can change its resistance value according to the intensity of the light it senses, that is, different light intensities can cause the resistance value to change.

[0078] In a specific embodiment, the light intensity detection unit 1312 also includes an ADC and a first resistor, the first end of the photoresistor is grounded, the second end of the photoresistor is connected to the input end of the ADC, and the third end of the photoresistor is the input end of the photoresistor, which is used to receive the light emitted by the light source driving unit; one end of the first resistor is connected to VCC, and the other end of the first resistor is connected to the input end of the ADC; the signal output from the output end of the ADC is used as a light intensity monitoring signal.

[0079] Please continue reading Figure 1In one embodiment, the first sampling circuit 12 includes an optical signal transmitting unit 121 and an optical signal receiving unit 122, wherein the optical signal transmitting unit 121 is used to transmit an optical signal and transmit it to the optical signal receiving unit 122 through the optical communication link 20, and the optical signal receiving unit 122 is used to receive the optical signal and convert it into an electrical signal.

[0080] When the battery pack is in a normal state, the optical signal emitted by the optical signal transmitting unit 121 will be transmitted through the optical communication link 20 to be received by the optical signal receiving unit 122. When the battery pack is in a thermal runaway state, gas or smoke will be generated in the battery pack. The gas or smoke generated in the battery pack will appear in the optical communication link 20, causing the propagation medium of the optical signal to change. Therefore, the optical signal emitted by the optical signal transmitting unit 121 will not be completely transmitted according to the optical communication link 20; then, the optical signal received by the optical signal receiving unit 122 will change, so that the electrical signal converted by the optical signal receiving unit 122 based on the received optical signal will change. When the battery is in a leaking state, the leaked electrolyte will flood multiple first battery management units 11, that is, it will flood the optical communication link 20 between multiple first battery management units 11, causing the propagation medium of the optical signal to change. Therefore, the optical signal emitted by the optical signal transmitting unit 121 will not be completely transmitted according to the optical communication link 20; then, the optical signal received by the optical signal receiving unit 122 will change, so that the electrical signal converted by the optical signal receiving unit 122 based on the received optical signal will change. Therefore, by the optical signal transmitting unit 121 transmitting an optical signal, the optical signal receiving unit 122 receiving the optical signal and converting the generated electrical signal based on the received optical signal, it is possible to determine whether the battery pack is in an abnormal state.

[0081] In a specific embodiment, the optical signal transmitting unit 121 and the optical signal receiving unit 122 are respectively arranged on different first battery management units 11. For example, the first battery management unit 11 is a data monitoring module, and the optical signal transmitting unit 121 and the optical signal receiving unit 122 are respectively arranged on different data monitoring modules.

[0082] In a specific embodiment, the number of optical communication links 20 is at least one, the number of first sampling circuits 12 corresponds to the number of optical communication links 20, and each first sampling circuit 12 is provided on a different first battery management unit 11. That is to say, there is a first sampling circuit 12 corresponding to the optical communication links 20 between different first battery management units 11, which is used to sample the optical signals transmitted by the optical communication links 20 between different first battery management units 11. If there are multiple optical communication links 20, then there are multiple electrical signals obtained by converting the optical signals transmitted by the optical communication links 20. Subsequently, it is possible to combine multiple electrical signals to determine whether the battery pack is in an abnormal state, thereby accurately determining whether the battery pack is in an abnormal state, thereby reducing the possibility of false alarms of battery pack abnormalities, and providing more accurate and effective safety warnings for battery pack abnormalities.

[0083] In a specific embodiment, the first sampling circuit 12 further includes at least one photoconductive element (not shown in the figure), and the at least one photoconductive element is used to transmit at least part of the optical signal emitted by the optical signal emitting unit 121 to the optical signal receiving unit 122. The setting of the photoconductive element can guide the transmission of the optical signal emitted by the optical signal emitting unit 121, so as to efficiently and stably transmit the optical signal emitted by the optical signal emitting unit 121 to the optical signal receiving unit 122 through the optical communication link 20.

[0084] The type of the optical waveguide element is not limited and can be specifically set according to actual needs. For example, the optical waveguide element is an optical waveguide, which is an optical waveguide element integrated on a chip and transmits optical signals in a waveguide layer by using the principle of light refraction and interference. For another example, the optical waveguide element is a grating, which is an optical waveguide element with a periodic structure and can decompose an optical signal into components of different wavelengths or realize diffraction and interference of an optical signal.

[0085] In addition, the number of the photoconductive elements is not limited and can be specifically set according to actual use needs. For example, the number of the photoelectric elements is 1 or 2.

[0086] In a specific embodiment, the optical signal transmitting unit 121 and the optical signal receiving unit 122 are located on the same horizontal plane. The optical signal transmitting unit 121 and the optical signal receiving unit 122 are located on the same horizontal plane, so that the transmission path of the optical signal is more direct, reducing the signal attenuation caused by angle deviation or too long path, which is conducive to the optical signal emitted by the optical signal transmitting unit 121 to be transmitted to the optical signal receiving unit 122 with the best intensity and clarity, thereby improving the efficiency and quality of optical signal transmission.

[0087] Of course, in other specific embodiments, the optical signal transmitting unit 121 and the optical signal receiving unit 122 may not be located on the same horizontal plane, but may be located on the same straight line. When the optical signal transmitting unit 121 and the optical signal receiving unit 122 are located on the same straight line, the optical signal emitted by the optical signal transmitting unit 121 can be transmitted to the optical signal receiving unit 122.

[0088] In a specific embodiment, the optical signal transmitting unit 121 is a light emitting diode. A light emitting diode is a semiconductor electronic component that can convert electrical energy into light energy. Its core part is a chip composed of a P-type semiconductor and an N-type semiconductor, and there is a transition layer between the P-type semiconductor and the N-type semiconductor. When the light emitting diode is in a forward working state, the current flows from the anode of the light emitting diode to the cathode, and the semiconductor crystal will emit light of different colors from ultraviolet to infrared. In addition, the light emitting diode is a cold light source, which is more energy-saving. The light emitting diode is a solid cold light source, and there is no loose part in the lamp body, so there are no disadvantages such as easy burning of the filament light and light decay. The light emitting diode has a fast response speed and is suitable for high-speed optical communication.

[0089] In a specific embodiment, the optical signal receiving unit 122 is a photodiode. A photodiode is an important semiconductor optoelectronic device, and its core part is a PN junction with photosensitive characteristics, which makes the photodiode extremely sensitive to changes in light. The photodiode is extremely sensitive to changes in light and can produce detectable current changes under weak light; the response time of the photodiode is very short and can quickly respond to changes in optical signals; the photodiode exhibits good stability during operation and can work stably for a long time without failure.

[0090] See also Figure 3 , Figure 3 is a flow chart of an embodiment of an abnormality detection method provided by the present application. It should be noted that if there are substantially the same results, this embodiment does not Figure 3 The process sequence shown is limited. Figure 3 As shown, this embodiment includes: Step S31: acquiring a first signal output by a first sampling circuit and a second signal output by a second sampling circuit.

[0091] In this embodiment, a first signal output by the first sampling circuit and a second signal output by the second sampling circuit are obtained; wherein the first signal is an electrical signal converted from an optical signal transmitted by an optical communication link, the optical communication link, the first sampling circuit and the second sampling circuit are all arranged in a battery pack, and the second signal is a monitoring signal in the battery pack.

[0092] Step S32: Determine whether the battery pack is in an abnormal state by combining the first signal and the second signal.

[0093] In this embodiment, the first signal and the second signal are combined to determine whether the battery pack is in an abnormal state. Whether the battery pack is in an abnormal state is determined by combining the electrical signal fed back by the first sampling circuit and the monitoring signal fed back by the second sampling circuit. The electrical signal and the monitoring signal are used as a condition for determining whether the battery pack is in an abnormal state. In other words, the electrical signal and the monitoring signal are each other's supplementary basis for determining whether the battery pack is in an abnormal state. This can accurately determine whether the battery pack is in an abnormal state, thereby reducing the possibility of false alarms of battery pack abnormalities and providing more accurate and effective safety warnings for battery pack abnormalities.

[0094] Among them, Figure 2 As shown, the second sampling circuit 13 includes a light intensity detection component 131, and the monitoring signal corresponds to a light intensity monitoring signal sampled by the light intensity detection component 131. The light intensity monitoring signal is in a decreasing trend within a preset time period, indicating that the battery pack is in an abnormal state. In other words, within the preset time period, if the light intensity monitoring signal sampled by the light intensity detection component 131 continues to decrease, it can be considered that the result indicated by the light intensity monitoring signal is that the battery pack is in an abnormal state.

[0095] When the battery pack is in a state of thermal runaway or leakage, gas, smoke or liquid will be generated in the battery pack, causing light to be scattered, refracted, etc. during propagation, resulting in a reduction in the amount of light reaching the target position, thereby reducing the light intensity at the target position, that is, causing the light intensity monitoring signal sampled at the target position by the light intensity detection component 131 to decrease. If the light intensity monitoring signal sampled at the target position by the light intensity detection component 131 continues to decrease within a preset time, it can be considered that the light intensity monitoring signal indicates that the battery pack is in an abnormal state.

[0096] See also Figure 4 , Figure 4 It is a structural schematic diagram of an embodiment of a battery pack provided by the present application. The present application also provides a battery pack, the battery pack 40 includes a battery cell 41 and a battery management system 10. The battery management system 10 is arranged in the battery pack 40, and the battery management system 10 includes a plurality of first battery management units 11, a first sampling circuit 12, a second sampling circuit 13 and a second battery management unit 14; there is an optical communication link 20 between the plurality of first battery management units 11, and signal interaction is performed through the optical communication link 20; the first sampling circuit 12 is used to sample the optical signal transmitted by the optical communication link 20 and convert it into an electrical signal; the second sampling circuit 13 is used to sample the monitoring signal in the battery pack 40; the second battery management unit 14 is used to output a status signal representing whether the battery pack 40 is in an abnormal state based on the electrical signal and the monitoring signal, wherein the abnormal state includes at least one of a thermal runaway state and a leakage state.

[0097] Therefore, the battery management system 10 determines whether the battery pack 40 is in an abnormal state by combining the electrical signal fed back by the first sampling circuit 12 and the monitoring signal fed back by the second sampling circuit 13, and uses the electrical signal and the monitoring signal together as a condition for determining whether the battery pack 40 is in an abnormal state. In other words, the electrical signal and the monitoring signal are each other's supplementary basis for judging whether the battery pack 40 is in an abnormal state. This can accurately determine whether the battery pack 40 is in an abnormal state, thereby accurately outputting a status signal representing whether the battery pack 40 is in an abnormal state, reducing the possibility of false alarm of the battery pack 40 abnormality, and providing a more accurate and effective safety warning for the battery pack 40 abnormality.

[0098] See also Figure 5 , Figure 5 It is a structural diagram of an embodiment of an electric device provided by the present application. The present application also provides an electric device 50, which includes a battery pack 40, and the battery pack 40 supplies power to the electric device 50. Since the battery pack 40 includes a battery management system 10, the battery management system 10 determines whether the battery pack 40 is in an abnormal state by combining the electrical signal fed back by the first sampling circuit 12 and the monitoring signal fed back by the second sampling circuit 13, and uses the electrical signal and the monitoring signal as a condition for determining whether the battery pack 40 is in an abnormal state. In other words, the electrical signal and the monitoring signal are each other's supplementary basis for determining whether the battery pack 40 is in an abnormal state, which can accurately determine whether the battery pack 40 is in an abnormal state, thereby accurately outputting a status signal representing whether the battery pack 40 is in an abnormal state, reducing the possibility of false alarms of abnormalities of the battery pack 40, and providing a more accurate and effective safety warning for abnormalities of the battery pack 40. Therefore, the battery pack 40 can stably and safely supply power to the electric device 50.

Claims

1. A battery management system, characterized in that: The battery management system is arranged in the battery pack, and includes: A plurality of first battery management units, wherein optical communication links are provided between the plurality of first battery management units, and signal interaction is performed through the optical communication links; A first sampling circuit, used for sampling the optical signal transmitted by the optical communication link and converting it into an electrical signal; A second sampling circuit is used to sample the monitoring signal in the battery pack; wherein the second sampling circuit includes a light intensity detection component, and the monitoring signal corresponds to a light intensity monitoring signal sampled by the light intensity detection component; The second battery management unit is used to output a status signal indicating whether the battery pack is in an abnormal state based on the electrical signal and the monitoring signal, wherein a decreasing trend of the light intensity monitoring signal within a preset time period indicates that the battery pack is in the abnormal state, and the abnormal state includes at least one of a thermal runaway state and a liquid leakage state.

2. The battery management system according to claim 1, characterized in that: The second battery management unit is used to output a status signal indicating that the battery pack is in an abnormal state in response to the signal value of the electrical signal sampled within the first time period being less than a preset threshold and the monitoring signal indicating that the battery pack is in an abnormal state.

3. The battery management system according to claim 2, characterized in that: The second sampling circuit also includes at least one of a sensor and a third battery management unit, and the monitoring signal corresponds to at least one of an environmental monitoring signal sampled by the sensor and a circuit monitoring signal sampled by the third battery management unit.

4. The battery management system according to claim 3, characterized in that: The second battery management unit is used to output a status signal representing that the battery pack is in an abnormal state in response to the signal value of the electrical signal sampled within the first time period being less than a preset threshold, the environmental monitoring signal indicating that the battery pack is in an abnormal state, and the presence of a battery cell-related monitoring signal indicating that the battery pack is in an abnormal state, wherein the battery cell-related monitoring signal includes the circuit monitoring signal and / or the light intensity monitoring signal.

5. The battery management system according to claim 4, characterized in that: The environmental monitoring signal includes at least one of an air pressure signal sampled by an air pressure sensor and a smoke signal sampled by a smoke sensor; the second battery management unit is used to output a first state signal indicating that the battery pack is in a thermal runaway state in response to the signal value of the electrical signal sampled within the first time period being less than a preset threshold, the air pressure signal or the smoke signal indicating that the battery pack is in an abnormal state, and the presence of the battery cell-related monitoring signal indicating that the battery pack is in an abnormal state; and / or, The environmental monitoring signal includes a leakage signal sampled by a leakage sensor; the second battery management unit is used to respond to the signal value of the electrical signal sampled within the first time period being less than a preset threshold, the leakage signal indicating that the battery pack is in an abnormal state, and the presence of the battery cell-related monitoring signal indicating that the battery pack is in an abnormal state, outputting a second status signal indicating that the battery pack is in a leakage state.

6. The battery management system according to claim 4, characterized in that: The battery cell related monitoring signal includes circuit monitoring data, and the circuit monitoring data includes at least one of the following: the voltage of the battery cell, and the battery cell temperature of the battery cell; wherein, the voltage of the battery cell indicates that the battery pack is in an abnormal state characterized by: the voltage is lower than the voltage threshold, and the battery cell temperature of the battery cell indicates that the battery pack is in an abnormal state characterized by at least one of the following: the battery cell temperature is higher than the temperature threshold, and the rate of increase of the battery cell temperature is higher than the rate threshold.

7. The battery management system according to claim 1, characterized in that: The light intensity detection component includes a light source driving unit and a light intensity detection unit. The light source driving unit is used to emit light, and the light intensity detection unit is used to detect the light intensity of the light to obtain the light intensity monitoring signal.

8. The battery management system according to claim 7, characterized in that: The light source driving unit and the corresponding light intensity detection unit are respectively arranged on opposite sides of the battery cell in the battery pack; And / or, the number of the light intensity detection components is at least one, the detection paths of all the light intensity detection components cover all battery cells in the battery pack, and the detection path of the light intensity detection component is a detection loop formed between the light source driving unit and the light intensity detection unit in the light intensity detection component; And / or, the light source driving unit is a light emitting diode; And / or, the light intensity detection unit includes a photoresistor.

9. The battery management system according to claim 1, characterized in that: The first sampling circuit includes an optical signal transmitting unit and an optical signal receiving unit; wherein the optical signal transmitting unit is used to emit the optical signal and transmit it to the optical signal receiving unit through the optical communication link, and the optical signal receiving unit is used to receive the optical signal and convert it into the electrical signal.

10. The battery management system according to claim 9, characterized in that: The optical signal transmitting unit and the optical signal receiving unit are respectively arranged on different first battery management units; And / or, the number of the optical communication links is at least one, the number of the first sampling circuits corresponds to the number of the optical communication links, and each of the first sampling circuits is arranged on a different first battery management unit.

11. The battery management system according to claim 9, characterized in that: The first sampling circuit further comprises at least one photoconductive element, and the at least one photoconductive element is used to conduct at least part of the optical signal emitted by the optical signal emitting unit to the optical signal receiving unit; And / or, the optical signal transmitting unit and the optical signal receiving unit are located on the same horizontal plane; And / or, the optical signal transmitting unit is a light emitting diode; And / or, the optical signal receiving unit is a photodiode.

12. The battery management system according to claim 1, characterized in that: The second battery management unit is the main control unit of the battery management system; And / or, one of the first battery management units is the main control unit, and at least one of the first battery management units is a data monitoring module of the battery pack.

13. An anomaly detection method, characterized in that: The method comprises: Acquire a first signal output by a first sampling circuit and a second signal output by a second sampling circuit; wherein the first signal is an electrical signal obtained by converting an optical signal transmitted by an optical communication link, the optical communication link, the first sampling circuit and the second sampling circuit are all arranged in a battery pack, and the second signal is a monitoring signal in the battery pack, wherein the second sampling circuit includes a light intensity detection component, and the monitoring signal corresponds to a light intensity monitoring signal obtained by sampling by the light intensity detection component; In combination with the first signal and the second signal, determine whether the battery pack is in an abnormal state; wherein, a decreasing trend of the light intensity monitoring signal within a preset time period indicates that the battery pack is in the abnormal state, and the abnormal state includes at least one of a thermal runaway state and a leakage state.

14. A battery pack, characterized in that: The battery pack comprises a battery cell and a battery management system as claimed in any one of claims 1 to 12.

15. An electrical equipment, characterized in that: The electrical device includes a battery pack, which supplies power to the electrical device. The battery pack is the battery pack according to claim 14.

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