Battery system and method of protecting the same

Abstract

A battery system includes a plurality of unit battery groups, a total switch, a current measuring unit, a plurality of slave units and a master unit. Each unit battery group includes a plurality of battery cells connected in series, and the plurality of unit battery groups are connected in series with each other. The total switch and the current measuring unit are connected in series with the unit battery groups. The current measuring unit is adapted to measure a measured system current value of the unit battery groups. The slave units are respectively electrically connected to the unit battery groups, and each slave unit is adapted to measure a physical parameter value of each battery cell in a corresponding unit battery group. The master unit is communicatively connected to the slave units and is adapted to: control the total switch to be turned off when an abnormality judged according to the physical parameter value or the measured system current value is a system abnormality; and execute a detection abnormality processing program when the abnormality judged according to the physical parameter value or the measured system current value is a detection abnormality.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a battery system and a protection method thereof. BACKGROUND

[0002] Air pollution is increasingly valued, and the call to replace fossil energy has prompted the rapid development of hybrid or pure electric vehicle industries, in which battery systems are essential key components. During the process of providing current to the load, the battery system needs to continuously detect whether there is an abnormality. If an abnormality occurs, the battery system must perform a corresponding variation mechanism to avoid damage to the battery system and / or the load.

[0003] However, current battery system protection judgments mostly rely on a single abnormal signal to start protection immediately, and all protection judgments are usually calculated by the main control unit, resulting in a large calculation burden on the main control unit.

[0004] Therefore, it is one of the goals of those skilled in the art to propose a battery system and a protection method thereof that can improve the aforementioned known problems. SUMMARY

[0005] The present disclosure relates to a battery system and a protection method thereof.

[0006] According to one embodiment of the present disclosure, a battery system is proposed. The battery system includes a plurality of unit battery groups, a total switch, a current measurement unit, a plurality of slave control units, and a master control unit. Each unit battery group includes a plurality of battery cores connected in series with each other, and the unit battery groups are connected in series with each other. The total switch and the current measurement unit are also connected in series with the unit battery groups. The current measurement unit is adapted to measure a system current value of the unit battery groups. The slave control units are respectively electrically connected to the unit battery groups, and each slave control unit is adapted to measure a physical parameter value of each battery core in the corresponding unit battery group. The master control unit is communicatively connected to the slave control units and is adapted to: control the total switch to be turned off when an abnormality determined according to the physical parameter value or the measured system current value is a system abnormality; and execute a processing program of the detection abnormality when the abnormality determined according to the physical parameter value or the measured system current value is a detection abnormality.

[0007] According to another embodiment of the present disclosure, a protection method for a battery system is proposed. The battery system is as described above. The protection method includes the following steps: the current measurement unit measures a system current value of the unit battery groups; each battery core measures a physical parameter value of each battery core in each unit battery group; the master control unit controls the total switch to be turned off when an abnormality determined according to the physical parameter value or the measured system current value is a system abnormality; and the master control unit executes a processing program of the detection abnormality when the abnormality determined according to the physical parameter value or the measured system current value is a detection abnormality.

[0008] To provide a better understanding of the above and other aspects of this disclosure, specific embodiments are described below in conjunction with the accompanying drawings: Attached Figure Description

[0009] Figure 1A A schematic diagram of a battery system according to an embodiment of the present disclosure is shown.

[0010] Figure 1B Draw Figure 1A Flowchart of the battery system protection method.

[0011] Figure 2 Draw Figure 1A The physical parameter curves of the battery system when various abnormalities occur.

[0012] Figure 3 A schematic diagram illustrating a plurality of slave control units connected in series with a master control unit according to an embodiment of the present disclosure is shown.

[0013] Figure 4 A diagram illustrating the current variation of a charger supplying power to a battery system according to an embodiment of this disclosure is shown.

[0014] Figure 5 Draw Figure 1A A schematic diagram of the slave control unit and the connected battery cells. Detailed Implementation

[0015] Please refer to Figures 1A, 1B and 2. Figure 1A shows a schematic diagram of a battery system 100 according to an embodiment of the present disclosure. Figure 1B shows a flowchart of the protection method of the battery system 100 in Figure 1A. Figure 2 shows a graph of physical parameters of the battery system 100 in Figure 1A when various abnormalities occur.

[0016] The battery system 100 includes several unit battery packs 110, a main switch 120, a current measurement unit 130, several slave units 140, and a master unit 150. Each unit battery pack 110 includes several battery cells 111 connected in series with each other, and the unit battery packs 110 are also connected in series with each other to form a series battery pack to increase the operating voltage of the battery system 100. The main switch 120 is connected in series with the unit battery packs 110 to control the power output and input of the series battery pack. The current measurement unit 130 is connected in series with the unit battery packs 110 and is adapted to measure the measured system current value I of one of the unit battery packs 110 (or the series battery pack). SSThe slave units 140 are respectively electrically connected to the unit battery packs 110, and each slave unit 140 is adapted to obtain a physical parameter value of each battery cell 111 in the corresponding unit battery pack 110. The master unit 150 is communicatively connected to the slave units 140, and the master unit 150 is adapted to: (1) when the abnormality is determined according to the physical parameter value or the measured system current value I SS When the abnormality is determined to be a system abnormality, the master unit 150 controls the main switch 120 to be turned off; and (2) when the abnormality is determined according to the physical parameter value or the measured system current value I SS When the abnormality is determined to be a detection abnormality, the master unit 150 executes a processing program for the detection abnormality. In the embodiment, the result of determining the abnormality state according to the physical parameter value is provided by the slave units 140, so that the burden of the master unit 150 can be reduced. It is noted that the measured system current value I SS refers to the current value returned to the master unit 150 by the current measuring unit 130.

[0017] In detail, the battery system 100 of the embodiment of the present disclosure obtains the physical parameter values of the battery cells 111 by the slave units 140 respectively, and then determines the abnormality, which is a kind of distributed operation battery system.

[0018] The current measuring unit 130, the slave units 140 and the master unit 150 are formed by electronic components, for example, physical circuits, or integrated circuits after semiconductor process packaging, such as semiconductor chips, semiconductor packages, etc. The slave units 140 are arranged in a circuit board (not shown), and the master unit 150 is arranged in another circuit board (not shown). Alternatively, the slave units 140 and the master unit 150 can be arranged in the same circuit board (not shown).

[0019] The aforementioned "physical parameter values" include, for example, the measured voltage value Vt and / or the measured temperature value Tt of each battery cell 111 connected to the battery pack 110 detected by the slave control unit 140. The aforementioned "detection anomalies" include, for example, anomalies such as short circuits, open circuits, and noise that cause detection failure. These detection failures do not cause a substantial failure of the battery system 100 (e.g., burnout, overload, or other failure modes that can substantially damage the battery system 100). The aforementioned "system anomalies" include, for example, malfunctions of the battery cell, slave control unit 140, or master control unit 150 itself, which may cause a substantial failure of the battery system 100 (e.g., burnout, overload, or other substantial damage). In this embodiment, the slave control unit 140 mainly performs physical value measurements of voltage and temperature, and directly performs calculations and judgments based on the measurement data. The master control unit 150 receives the judgment results from the slave control unit 140, confirms them, and controls the switching of the main switch 120. A few functions that cannot be judged by the slave control unit 140, such as system abnormalities caused by abnormal current detection or excessive current, are judged by the master control unit 150. Therefore, the burden on the master control unit 150 can be greatly reduced. In other words, most of the measurement functions, data calculations, and judgments of the entire battery system 100 are shared by the majority of slave control units 140, while the master control unit 150 performs only a small portion of the judgments and switching of the main switch 120, which can greatly reduce its workload.

[0020] In this embodiment, the current measuring unit 130 measures the current value I of the system being measured. SS Then, the measured system current value I was recorded. SS The data is transmitted to the main control unit 150, which then processes the measured system current value I. SS The calculation and the calculation based on the measured system current value I SS Perform anomaly detection and simultaneously set the current value I. SS The signal is broadcast to the slave control unit 140 to assist the slave control unit 140 in calculating and judging voltage and temperature anomalies. However, in other embodiments, if the current measurement unit 130 itself has data processing capabilities, then the current measurement unit 130 will transmit the signal to the slave control unit 140 upon measuring the system current value I. SS Afterwards, data calculations and anomaly detection can be performed directly, and then the measured system current value I can be used. SS The result of the anomaly detection is transmitted to the main control unit 150. Specific implementation methods are not limited to those listed.

[0021] Although not shown, each battery cell 111 includes a voltage measuring device and a temperature measuring device, and the slave control unit 140 can obtain the measured voltage value V from the voltage measuring device. t And obtain the measured temperature values ​​T from the temperature measuring instrument. t The slave control unit 140 can determine the voltage value V of at least one of the coupled battery cells 111 based on the measured voltage value.t and / or the measured temperature value T t performing abnormality judgment.

[0022] In an embodiment, the slave unit 140 is adapted to: (1) acquire the measured system current value I SS broadcasted by the master unit 150; (2) judge whether the abnormality occurred in the battery system 100 is a system abnormality or a detection abnormality according to the measured voltage value V t , the measured temperature value T t and the measured system current value I SS . In addition, the measured system current value I SS is, for example, a detection value of the string current (e.g., system current I S ) of all the unit battery groups 110 connected in series in the battery system 100.

[0023] The master unit 150 and the slave units 140 are connected in communication series, and a common communication interface such as RS485, CANBus or wireless communication is adopted. In an embodiment, the master unit 150 can broadcast to all the slave units 140 and ask one or some of the slave units 140 to return the information detected thereby. When all the slave units 140 receive the request of the master unit 150, only the slave units 140 asked by the master unit 150 need to return. Any slave unit 140 can receive the information broadcasted by all the units (including the master unit 150 and the other slave units 140) on the communication transmission line, so that any slave unit 140 and the master unit 150 can acquire the information required for calculating and judging the detection abnormality and the system abnormality. In this way, any slave unit 140 can judge whether the battery cells 111 coupled thereto are abnormal in addition to judging whether the battery cells 111 coupled to any other slave unit 140 are abnormal.

[0024] As shown in FIG. 1B, the protection method of the battery system 100 includes: in step S110, the current measuring unit 130 measures the measured system current value I SS of the unit battery group 110; in step S120, the voltage measurer and the temperature measurer of each slave unit 140 measure the voltage and the temperature physical parameter values of each string battery cell 111 in the unit battery group 110 connected thereto; in step S130, when the abnormality judged according to the physical parameter values or the measured system current value I SS is a system abnormality, the master unit 150 controls the main switch 120 to be turned off; when the abnormality judged according to the physical parameter values or the measured system current value I SS is a detection abnormality, the master unit 150 executes the corresponding detection abnormality processing program.

[0025] The following further illustrates several different aspects of "system abnormality" and "detection abnormality". When a "detection abnormality" occurs, the slave unit 140 can execute a detection abnormality processing program, for example, ignoring the abnormal physical parameter value, i.e., not considering the abnormal physical parameter value.

[0026] The first case of "system abnormality" is

[0027] The slave unit 140 can determine a system abnormality according to the temperature change of the battery cell 111. For example, the slave unit 140 is adapted to: (1) determine whether the measured temperature value T t of the measured battery cell 111' increases sharply in a unit time; (2) when the measured temperature value T t of the measured battery cell 111' increases sharply in a unit time, determine whether the measured temperature value T t of the adjacent battery cell 111" increases sharply in a unit time; (3) when the measured temperature value T t of the adjacent battery cell 111" increases sharply in a unit time, determine that the abnormality of the battery system 100 belongs to "system abnormality".

[0028] In detail, as shown in FIG. 2, taking temperature as an example of a physical parameter value, curve C11 represents the temperature change of the measured battery cell 111', curves C12 and C13 respectively represent the temperature changes of the adjacent battery cells 111", and curves C14-C17 represent the temperature changes of normal battery cells 111. According to these curves C11-C17, it is determined that the temperature rise of the measured battery cell 111' due to internal short circuit or failure of the measured battery cell 111' itself is "system abnormality", and the temperature rise of the measured battery cell 111' will cause the adjacent battery cell 111" to also rise in temperature, so the slave unit 140 determines that the measured battery system 100 has "system abnormality" according to the detection of "simultaneous temperature rise of the measured battery cell 111' and the adjacent battery cell 111". At this time, the slave unit 140 informs the master unit 150 of the result of determining "system abnormality" through communication, and the master unit 150 controls the main switch 120 to be turned off and starts the protection measures of the system for the over-temperature situation, so as to achieve the protection effect.

[0029] In addition, the measured battery cell 111' in this case can be any or each of all battery cells, and is not limited by the reference numerals in FIG. 1A.

[0030] For example, the selection of the measured battery cell 111' can be the one with the highest temperature in the single battery pack 110. That is, when the slave unit 140 determines the abnormal state of the system according to the temperature change of the battery cell 111, the slave unit 140 will first determine the measured battery cell 111' with the highest measured temperature value Tt in the corresponding battery 110. In another embodiment, the selection of the measured battery cell 111' can be the one with the lowest temperature in the single battery pack 110, and when the slave unit 140 determines the result of "system abnormality", the master unit 150 can start the protection measures of the system for the low temperature condition. In other embodiments, the selection of the measured battery cell 111' can also be the two battery cells 111 with the largest temperature difference in the single battery pack 110 for determination. The specific embodiments are not limited to the listed ones.

[0031] The second case of "system abnormality" is

[0032] The slave unit 140 can determine the system abnormality according to the voltage change of the battery cell 111. For example, the slave unit 140 is adapted to: (1). determine the measured voltage value V t of the measured battery cell 111' in the unit time whether it exceeds a limit value; (2). when the measured voltage value V t of the measured battery cell 111' exceeds the limit value in the unit time, compare the measured system current value I SS broadcasted by the master unit 150; (3). determine whether the measured system current value I SS changes synchronously with the measured voltage value V t of the measured battery cell 111'; (4). when the measured system current value I SS changes synchronously with the measured voltage value V t of the measured battery cell 111', determine that the abnormality of the battery system 100 belongs to "system abnormality".

[0033] In detail, when the external device 10 (such as a motor) connected to the battery system 100 is short-circuited, the measured system current value I SS and the measured voltage value V t will change synchronously and sharply, for example, the measured system current value I SS rises sharply and the measured voltage value V t (or, the string voltage) drops sharply. In this case, the main switch 120 must be turned off immediately to avoid damage to the battery system 100 due to the short circuit, so the master unit 150 determines this case as "system abnormality" and directly starts the response mechanism to turn off the main switch 120.

[0034] In one embodiment, the aforementioned "limit value" may be, for example, a voltage value, including the voltage difference limit based on the series voltage change rate estimated according to the maximum current of the battery system 100, or the boundary value of the safe operating range declared by the specifications of each battery cell 111, such as the highest charging voltage and the lowest discharging voltage that the battery cell 111 can withstand as limit values. For example, a temperature value may include the boundary value of the safe operating range declared by the battery cell 111, such as the highest and lowest temperatures as limit values. For example, a current value may include the maximum charging current that can be withstood during the charging and discharging phases respectively as limit values. Furthermore, the battery cell 111' under test in this case may be any one or each of all battery cells 111.

[0035] In one embodiment, the selected battery cell 111' can be the one with the highest voltage in the single-cell battery pack 110. That is, when the slave control unit 140 determines the abnormal state of the system based on the voltage change of the battery cell 111, it will preferentially search for the cell with the highest measured voltage value V in the corresponding cell 110. t The selection is made by choosing the battery cell 111' under test. In another embodiment, the battery cell 111' under test can be the one with the lowest voltage in the single-cell battery pack 110. In other embodiments, the battery cell 111' under test can also be the two battery cells 111 with the largest voltage difference in the single-cell battery pack 110. The specific implementation is not limited to the examples listed.

[0036] In one embodiment, any anomaly that does not fall under the aforementioned "system anomaly" category can be classified as a "detection anomaly," but this is not intended to limit the embodiments of this disclosure. Several cases of "detection anomalies" are described below.

[0037] The first scenario of "abnormal detection" —

[0038] The main control unit 150 or the slave control unit 140 can determine and detect abnormalities based on the voltage changes of the battery cell 111. For example, the system current value I measured by the main control unit 150 or the current measurement unit 130... SS It can be used with the voltage value V of each battery cell 111 measured by the control unit 140. t With temperature value T t Based on the measured system current value I SS Measured voltage value V t With the measured temperature value T t The way these three values ​​change determines that the abnormality occurring in battery system 100 is a "detection abnormality".

[0039] In detail, if the battery system 100 is in a discharging state, the measured system current value I SS The voltage suddenly drops to zero, but the measured voltage V of each cell 111 within all cell packs 110 remains unchanged.t However, no corresponding bounce change was observed, indicating that the measured system current value I was being transmitted or detected. SS If the circuit or line (such as transmission line W1 in Figure 1) is abnormal (e.g., broken wire, poor contact, etc.), this is considered "current detection abnormality".

[0040] The second scenario of "abnormal detection" —

[0041] The slave control unit 140 can determine the temperature based on several measured temperature values ​​T of several battery cells 111. t Whether the change is synchronous determines whether the abnormality belongs to the detection abnormality. For example, the slave control unit 140 is suitable for: (1) determining the measured temperature value T of the tested battery cell 111'. t 'Whether the temperature rises sharply within a unit of time; (2). When the measured temperature value T of the tested battery cell 111' t When the temperature rises sharply within a unit of time, the measured temperature value T of the battery cell 111 adjacent to the tested battery cell 111 is determined. t "Whether it rises synchronously; (3). When the measured temperature value T of the adjacent battery cell 111" t "When the battery system 100 does not rise synchronously, the abnormality is judged to be a "detection abnormality".

[0042] In detail, if the measured temperature value T of the tested battery cell 111' per unit time... t The temperature rises sharply, but the measured temperature T of adjacent or other battery cells 111 per unit time is... t The failure to synchronize the temperature rise indicates that the measured temperature value T of the tested battery cell 111' is being transmitted or detected. t The circuit or wiring is abnormal (e.g., open wire, short circuit, poor contact, etc.), which falls under the category of "temperature detection abnormality".

[0043] The third scenario of "abnormal detection" —

[0044] The slave control unit 140 can determine the system current value I based on the measured value. SS The measured voltage value V corresponds to the other battery cells 111. t Whether the change is synchronous determines whether the abnormality belongs to the detected abnormality. For example, the slave control unit 140 is adapted to: when the measured voltage value V of the tested battery cell 111' is... t The change in ' and the measured voltage value V of the other of the battery cells 111 t The changes are inconsistent, and the measured system current value I SS The measured voltage value V corresponding to the other of the battery cells 111 t When synchronous changes occur, the abnormality that occurs in the battery system 100 is classified as a "detection abnormality".

[0045] In detail, when the measured voltage value V of the tested battery cell 111' is... t 'The measured voltage value V of other battery cells 111' t Inconsistent changes indicate that the measured voltage value V of the tested battery cell 111' is being transmitted or detected. t The circuit or wiring is abnormal (e.g., broken wire, poor contact, etc.), which falls under the category of "voltage detection abnormality".

[0046] The fourth type of "detection anomaly" —

[0047] The slave control unit 140 can determine whether an anomaly is a detection anomaly based on whether the physical parameter value curve of the tested battery cell 111' has an equal offset from the physical parameter value curves of other battery cells 111. For example, the slave control unit 140 is adapted to determine that the anomaly occurring in the battery system 100 is a "detection anomaly" when the change in the physical parameter value of the tested battery cell 111' has an equal offset from the change in the physical parameter value of other battery cells 111. For example, as shown in Figure 2, curves C21 and C22 have an equal offset from the physical parameter value curves C14 to C17 of normal battery cells 111 or the average physical parameter value curve. Specifically, curve C21 is offset upwards and curve C22 is offset downwards, both of which indicate a fault in the measuring instrument for this physical parameter. Therefore, the slave control unit 140 can determine this situation as a "detection anomaly".

[0048] The fifth type of "abnormal detection" —

[0049] As shown in Figure 2, the fluctuating physical parameter values ​​indicated by curve C3 are considered noise. The slave control unit 140 can adjust the values ​​based on the physical parameter values ​​or the measured system current value I. SS To determine the abnormal condition of the system, under normal conditions, changes in current will correspondingly cause changes in voltage. Therefore, voltage and current are linked. When the measured voltage value V of the tested battery cell 111' is... t 'and the measured system current value I SS There is no correlation; for example, when the system current Is is zero, the voltage should be a stable value, but if the measured system current value I... SS The measured voltage V of the tested battery cell 111' is zero. t If irregular jittering changes occur, similar to curve C3, this situation is judged as "detection anomaly".

[0050] The sixth type of "abnormal detection" —

[0051] The slave control unit 140 can determine system abnormalities based on the temperature changes of the battery cell 111. For example, the slave control unit 140 is adapted to: when the measured temperature value T of the tested battery cell 111' is... tIn the case of an instantaneous jump or drop, the abnormality of the battery system 100 is determined to be a "detection abnormality". As shown in FIG. 2, taking the temperature as an example of the physical parameter value, curves C4 and C5 represent the measured temperature value T t In curve C4, when the measured temperature value T t In the case of an instantaneous drop to 0, it indicates that the temperature measurer of the battery cell 111 has a detection abnormality, such as a detection short circuit or a temperature measurer abnormality. The control unit 140 determines this case to be a "detection abnormality". In curve C5, when the measured temperature value T t In the case of an instantaneous jump, it indicates that the temperature measurer of the battery cell 111 has a detection abnormality, such as a detection short circuit or a temperature measurer abnormality. The control unit 140 determines this case to be a "detection abnormality". In detail, the temperature change is usually slow, so if the measured temperature value T t In the case of an instantaneous jump or drop, the abnormality of the battery system 100 is determined to be a "detection abnormality". As shown in FIG. 2, taking the temperature as an example of the physical parameter value, curves C4 and C5 represent the measured temperature value T

[0052] In summary, any control unit 140 can determine whether any battery cell (e.g., the measured battery cell 111') has a detection abnormality or a system abnormality according to the measured temperature value T t and / or the measured voltage value V t and / or the measured system current value I SS broadcasted by the master control unit 150, and returns the determination result to the master control unit 150. The master control unit 150 determines whether to turn off the main switch 120 according to the determination result. When a "detection abnormality" occurs, the control unit 140 and / or the master control unit 150 can ignore the physical parameter value related to the measured battery cell 111'. When a "system abnormality" occurs, the master control unit 150 can turn off the main switch 120 to protect the battery system 100. In an embodiment, the master control unit 150 can also determine the type of protection measures to be activated according to the determination result, such as overvoltage protection, overtemperature protection, etc.

[0053] The seventh case of "detection abnormality" is

[0054] Please refer to FIG. 3, which shows a schematic diagram of a plurality of slave units 140 and a master unit 150 connected in series according to an embodiment of the present disclosure. The master unit 150 and the slave units 140 are connected in series in communication, and the slave units 140 include communication ports 140A and 140B, which are respectively arranged at opposite ends of the slave units 140 connected in series.

[0055] The master unit 150 further includes a first communication switch 151, a second communication switch 152, and a communication control unit 153. The communication port of the communication control unit 153 is coupled to one end of the first communication switch 151 and the second communication switch 152. In this embodiment, the communication structure is described by taking an example of one master unit 150 connected with three slave units 140, 140', and 140", but the present disclosure is not limited thereto. The first communication switch 151 is coupled to the communication port 140A of the first slave unit 140 at the other end opposite to the communication control unit 153, and the first communication switch 151 is adapted to turn on or turn off the communication with the first slave unit 140. The communication port 140A' of the second slave unit 140' is coupled to the communication port 140B of the first slave unit 140, and the communication port 140A' is adapted to transmit the information of the second slave unit 140' to the communication port 140A of the first slave unit 140 via the communication port 140B, and then transmit the information to the communication control unit 153 via the first communication switch 151 for information reception. Similarly, the communication port 140A" of the third slave unit 140" is coupled to the communication port 140B' of the second slave unit 140', and the communication port 140A" is adapted to transmit the information of the third slave unit 140" to the communication control unit 153 via the communication port 140A and the first communication switch 151 for information reception, and the communication port 140B" of the third slave unit 140" is directly connected to the second communication switch 152 for transmitting data to the communication control unit 153. The communication switches 151 and 152 are turned on at the same time, for example, only one switch is turned on, to avoid the communication signal interference on the communication control unit 153 caused by the simultaneous turn-on of the first communication switch 151 and the second communication switch 152. The first communication switch 151 and the second communication switch 152 are adapted to connect the communication control unit 153 and the communication of all the slave units 140, and the first communication switch 151 is the main communication switch (main switch), and the second communication switch 152 is the auxiliary communication switch (auxiliary switch). The communication control unit 153 is adapted to: (1) determine whether the return signals (e.g., the measured voltage value V t and / or the measured temperature value T t ) of all the slave units 140 are received; and (2) when the return signals of all the slave units 140 are not received, turn on the first communication switch 151 and the second communication switch 152 alternately to receive the return signals of all the slave units 140.

[0056] In detail, in the normal condition of the battery system 100, the communication control unit 153 can obtain all the feedback signals from the slave units 140 by turning on the first communication switch 151. However, when an abnormality occurs in the communication line, for example, the coupling between the communication port 140B' and the communication port 140A" is abnormal, the communication control unit 153 can only receive the feedback signals from the first slave unit 140 and the second slave unit 140' through the first communication switch 151, and cannot receive the feedback signal from the third slave unit 140". When this condition occurs, the master unit 153 will turn off the first communication switch 151 and turn on the second communication switch 152 in order to receive the feedback signal from the third slave unit 140". At this time, the communication control unit 153 can only receive the feedback signal from the third slave unit 140" through the second communication switch 152. Therefore, the communication control unit 153 can still receive all the feedback signals from the slave units 140 by repeatedly switching the first communication switch 151 and the second communication switch 152, and can determine the abnormal position of the communication line between the second slave unit 140' and the third slave unit 140' from the feedback information received from the first communication switch 151 and the second communication switch 152.

[0057] In an embodiment, if the feedback information from all the slave units 140 cannot be obtained when the first communication switch 151 is turned on, it is determined that an abnormality is detected, and this abnormality belongs to the "communication abnormality". If the communication abnormality occurs, the processing procedure for detecting the abnormality is that the master unit 150 turns on the second communication switch 152 to assist in receiving the feedback information from the slave units 140, and switches the communication circuits corresponding to the first communication switch 151 and the second communication switch 152 in turn to obtain the feedback information from all the slave units 140. In an embodiment, the communication control unit 153 can determine the position of the communication abnormality according to the feedback information from the first communication switch 151 and the second communication switch 152.

[0058] In the embodiment, the communication control unit 153 is coupled with all the slave units 140 through the first communication switch 151 and the second communication switch 152. However, in other embodiments, the communication control unit 153 can be coupled with the slave units 140 through a three-way switch. In detail, the three-way switch has three endpoints connected to the communication control unit 153, the communication port 140A and the communication port 140B. When the three-way switch is turned on, the communication control unit 153 can only be connected to the slave units 140 through the communication port 140A or the communication port 140B, and the functions of the above-mentioned embodiments can also be achieved.

[0059] The eighth case of "detecting abnormality"

[0060] Referring to FIG. 4, a graph of current variation of the external device 10 supplying power to the battery system 100 is shown according to an embodiment of the present disclosure. In this embodiment, the external device 10 is, for example, a charger. When the external device 10 is electrically connected to the battery system 100, the master control unit 150 is adapted to: (1) request the external device 10 to supply a test current to the battery system 100; (2) determine whether a first current difference absolute value ΔI1 between a first test current value I t1 measured by the external device 10 and a system current value I S1 measured by the battery system 100 is greater than a permissible current error; (3) when the first current difference absolute value ΔI1 is greater than the permissible current error, further determine whether the battery system 100 has an amount of power equal to or higher than a safety value, for example, a value higher than 20%; (4) when the battery system 100 has an amount of power lower than the safety value, control the general switch 120 to be turned on so that the external device 10 continues to charge the battery system 100 until the battery system 100 has an amount of power equal to the safety value; (5) when the first current difference absolute value ΔI1 is greater than the permissible current error and the battery system 100 has an amount of power equal to or higher than the safety value, control the general switch 120 to be turned off. Here, the first test current value I t1 measured by the external device 10, and the system current value I S1 measured by the current measurement unit 130 in the battery system 100. In addition, when the current difference absolute value ΔI1 is less than the permissible current error, the external device 10 normally charges the battery system 100, for example, the external device 10 supplies a charging current I C to the battery system 100. The current difference absolute value ΔI1 is expressed as ΔI1 = abs(I t1 -I S1 ), and the permissible error of ΔI1 is, for example, less than 3%.

[0061] In detail, when the absolute value of the current difference is greater than the allowable current error, it indicates that the battery system 100 has a "current detection abnormality", and the processing procedure for the current detection abnormality is that when the electric storage amount of the battery system 100 is equal to or higher than a safety value, the master control unit 150 controls the main switch 120 to be turned off to avoid the possible risk caused by the continuous charging of the battery system 100. In another embodiment, although the absolute value of the current difference is greater than the allowable current error, since the electric storage amount of the battery system 100 is lower than the safety value, the processing procedure for the current detection abnormality can be that the master control unit 150 controls the main switch 120 to be kept on so that the external device 10 continues to charge the battery system 100 until the electric storage amount of the battery system 100 reaches the safety value or the total voltage of the battery system 100 is higher than the safety value, thus avoiding the damage of the battery system 100 caused by the too low electric storage amount. The aforementioned "safety value" is, for example, an electric storage amount that allows the battery system 100 itself or its user to have sufficient time for emergency response.

[0062] The ninth case of "detection abnormality"

[0063] As shown in FIG. 4, the master control unit 150 is further adapted to: (1) request the external device 10 to provide a first test current to the battery system 100; (2) determine whether the absolute value of the first current difference between the first test current value I t1 of the first test current and the corresponding measured system current value I S1 is greater than an allowable current error; (3) request the external device 10 to provide a second test current to the battery system 100, wherein the second test current value I t2 of the second test current is substantially higher than the first test current value I t1 ; (4) determine whether the absolute value of the second current difference between the second test current value I t2 and the corresponding measured system current value I S2 is greater than the allowable current error; (5) when either the absolute value of the first current difference ΔI1 or the absolute value of the second current difference ΔI2 is greater than the allowable current error, further determine whether the electric storage amount of the battery system 100 is equal to or higher than a safety value, for example, a value higher than 20%; (6) when the electric storage amount of the battery system 100 is lower than the safety value, control the main switch 120 to be turned on so that the external device 10 continues to charge the battery system 100 until the electric storage amount of the battery system 100 reaches the safety value or the total voltage of the battery system 100 is higher than the safety value; (7) when either the absolute value of the first current difference ΔI1 or the absolute value of the second current difference ΔI2 is greater than the allowable current error, and the electric storage amount of the battery system 100 is equal to or higher than the safety value, control the main switch 120 to be turned off. Wherein, the first test current value I t1 is substantially lower than the second test current value I t2is the current value measured by the external device 10, while the measured system current value I S1 is the current value measured by the external device 10, while the measured system current value I S2 is the current value measured by the external device 10, while the measured system current value I C is the current value measured by the external device 10, while the measured system current value I C may be between the first test current value I t1 and the second test current value I t2 , but the embodiments of the present disclosure are not limited thereto.

[0064] In detail, when the first current difference absolute value ΔI1 and the second current difference absolute value ΔI2 are greater than the allowable current error, it indicates that the battery system 100 has a "current detection abnormality", and the processing procedure for the current detection abnormality is as follows: when the electric storage amount of the battery system 100 is equal to or higher than a safety value, the master control unit 150 controls the main switch 120 to be turned off, so as to avoid the possible risks caused by the battery system 100 continuing to use the distorted current value, such as the distorted current value possibly causing the current protection function of the battery system to malfunction in use. In another embodiment, although the first current difference absolute value ΔI1 and the second current difference absolute value ΔI2 are greater than the allowable current error, since the electric storage amount of the battery system 100 is lower than the safety value, the processing procedure for the current detection abnormality is as follows: the master control unit 150 controls the main switch 120 to remain on, so that the external device 10 continues to charge the battery system 100, until the electric storage amount of the battery system 100 reaches the safety storage amount range, or the total voltage of the battery system 100 is higher than the safety value, so as to avoid the battery system 100 being damaged due to the electric storage amount being too low. The aforementioned "safety value" is, for example, an electric storage amount that allows the battery system 100 itself or its user to have sufficient time for emergency response.

[0065] As known from the eighth and ninth "detection abnormality" cases described above, when the external device 10 is electrically connected to the battery system 100, the master control unit 150 can determine whether a "current detection abnormality" occurs. When a "current detection abnormality" occurs, the battery system 100 is continuously charged when the electric storage amount of the battery system 100 is lower than a safety value, until the electric storage amount reaches the safety value or the total voltage of the battery system 100 is higher than the safety value, and then the main switch 120 is turned off. In addition, when the current difference absolute value is lower than the allowable current error, it indicates that no "current detection abnormality" occurs, and the external device 10 can normally charge the battery system 100.

[0066] The tenth case of "detection abnormality" is as follows:

[0067] Referring to FIG. 5, a schematic diagram of the slave unit 140 and the connected battery cell 111 of FIG. 1A is shown. The slave unit 140 includes a first battery switch 141, a second battery switch 142, a slave voltage measurer 143, a comparison voltage measurer 144, and a slave controller 145. The first battery switch 141 and the second battery switch 142 are switchably connected to or disconnected from the two ends a and b of the measured battery cell 111' of the battery cell 111. The slave voltage measurer 143 is electrically connected to the measured battery cell 111' and is adapted to measure a first measured voltage VI of the measured battery cell 111'. The comparison voltage measurer 144 is electrically connected to the first battery switch 141 and the second battery switch 142 and is adapted to measure a second measured voltage V2 of the measured battery cell 111'. The first measured voltage VI is the voltage value of the measured battery cell 111' measured by the slave voltage measurer 143, and the second measured voltage V2 is the voltage value of the same measured battery cell 111' measured by the comparison voltage measurer 144. The slave controller 145 is coupled to the slave voltage measurer 143 and the comparison voltage measurer 144 and is adapted to: (1) control the first battery switch 141 and the second battery switch 142 to electrically connect the measured battery cell 111' to the comparison voltage measurer 144; (2) determine whether an absolute value of a voltage difference AV (AV = abs(V1-V2)) between the first measured voltage VI of the measured battery cell 111' and the second measured voltage V2 measured by the comparison voltage measurer 144 is greater than a permissible voltage error (e.g., 5mV); and (3) when the absolute value of the voltage difference AV is greater than the permissible voltage error, determine that a "series voltage measurement abnormality" occurs, and output a detection abnormality signal SI to the master unit 150 via the series transmission line W1.

[0068] The first measured voltage VI and the second measured voltage V2 are the voltage difference between the two ends a and b of the measured battery cell 111', for example. In addition, the measured battery cell 111' in this case can be any or each of all the battery cells.

[0069] In one embodiment, as shown in FIG. 5, each slave unit 140 includes a plurality of battery switch groups 146, each battery switch group 146 includes a first battery switch 141 and a second battery switch 142, and each battery cell 111 is electrically connected to a battery switch group 146. In detail, two ends a and b of each battery cell 111 are electrically connected to a first battery switch 141 and a second battery switch 142, respectively. The first battery switch 141 and the second battery switch 142 are switchable to be on or off at the two ends a and b of each battery cell 111. A slave voltage measurer 143 is electrically connected to the battery cell 111 and adapted to measure a first measured voltage VI of each battery cell 111. A comparison voltage measurer 144 is electrically connected to the first battery switch 141 and the second battery switch 142 and adapted to measure a second measured voltage V2 of each battery cell 111. The first measured voltage VI is the voltage value of each battery cell 111 measured by the slave voltage measurer 143, and the second measured voltage V2 is the voltage value of each battery cell 111 measured by the comparison voltage measurer 144. A slave controller 145 is coupled to the slave voltage measurer 143 and the comparison voltage measurer 144 and adapted to: (1) alternately control each battery switch group 146 so that each battery cell 111 is alternately electrically connected to the comparison voltage measurer 144; (2) determine whether the absolute value of the voltage difference ΔV between the first measured voltage VI and the second measured voltage V2 of each battery cell 111 is greater than a permissible voltage error; and (3) when the voltage difference ΔV is greater than the permissible voltage error, output a detection abnormality signal SI to the master unit 150 through the serial transmission line Wl.

[0070] In the embodiment, each battery switch group 146 is alternately switched so that each battery cell 111 is alternately electrically connected to the comparison voltage measurer 144, i.e., at one time point, only one battery switch group 146 in the battery switch groups 146 is on, and the remaining battery switch groups 146 are off, so that the corresponding battery cell 111 is electrically connected to the comparison voltage measurer 144, and thus at the same time point, only the voltage V of one battery cell 111 is transmitted to the comparison voltage measurer 144. In this way, the mutual interference of multiple voltages V transmitted to the comparison voltage measurer 144 at the same time can be avoided.

[0071] As shown in FIG. 5, each slave unit 140 further includes a first bus bar 147 and a second bus bar 148. The first bus bar 147 is connected to the first battery switch 141, which is equivalent to being connected to the positive electrode of the battery cell 111' to be measured, and the second bus bar 148 is connected to the second battery switch 142, which is equivalent to being connected to the negative electrode of the battery cell 111' to be measured. The first bus bar 147 and the second bus bar 148 are electrically connected to the comparison voltage measurer 144. In this way, when the first battery switch 141 and the second battery switch 142 of the battery switch group 146 are turned on, the battery cell 111, the turned-on first battery switch 141 and the second battery switch 142, the first bus bar 147, the second bus bar 148, and the comparison voltage measurer 144 form a loop, and the voltage V of the battery cell 111 can be transmitted to the comparison voltage measurer 144 through the loop.

[0072] The "determination of the abnormality of the series voltage measurement" of the tenth aspect described above can be performed once after the external device 10 is started. For example, when the external device 10 is a vehicle (e.g., an automobile), the determination of the abnormality of the series voltage measurement can be performed once when the vehicle is started (Key on). The external device 10 can also be a charging station, and the determination of the abnormality of the series voltage measurement can be performed before the vehicle is ready for charging.

[0073] In an embodiment, the battery system 100 further includes an indicator 160 (shown in FIG. 1A), and the indicator 160 is coupled to the master unit 150. When a detection abnormality occurs during use of the battery system 100, the master unit 150 can control the indicator 160 to output a detection abnormality alarm signal S2 (shown in FIG. 1A). The indicator 160 includes, for example, a display screen, a light emitter, and / or a loudspeaker, and the detection abnormality alarm signal S2 is, for example, text, colored light, a symbol, and / or an alarm sound. As long as the detection abnormality alarm signal S2 can alert a user of the occurrence of a detection abnormality, the embodiments of the present disclosure do not limit the embodiments of the indicator 160 and the detection abnormality alarm signal S2.

[0074] When a detection abnormality occurs during the use of the battery system 100, if the detection abnormality does not affect the safety and reliability of the use of the battery system 100 (for example, a temperature signal detection abnormality, but because there are many temperature signals, the safety can be determined by other temperature signals), the main control unit 150 can ignore the detection abnormality and allow the battery system 100 to continue to be used. However, if the detection abnormality affects the safety and reliability of the battery system 100 (for example: abnormality of voltage and current signals), different responses will be taken according to the following (1) and (2): (1). When the battery system 100 is in a non-use state, the main control unit 150 switches the switch to stop power supply until the power supply is restored after the maintenance is completed; (2). When the battery system 100 is in a use state, based on the battery system 100, the power supply is immediately suspended, which may cause safety risks, so the response of the main control unit 150 can be: (2-1). Load reduction (such as reducing the output of the system current value IS) use (for example, finding that the string voltage measurement signal is broken or offset during driving), or (2-2). Start the power-off countdown mode (for example: finding that the current is 0 during driving, which may be a broken current measurement signal), during the power-off countdown, the user can guide the system to a safe shutdown state, and then the battery system 100 enters the power-off mode.

[0075] According to the foregoing embodiments, the battery system 100 and the protection method of the battery system according to the present disclosure are designed by distributed operation, which transfers most of the abnormal state judgment functions to the slave control unit 140 to reduce the burden of the main control unit 150. At the same time, through the comparison of multiple measurements, the abnormal state is further divided into two categories: system abnormality and detection abnormality, and different processing procedures are given to the system abnormality and the detection abnormality to provide a reliable battery protection function.

[0076] In summary, although the present disclosure has been disclosed as above, it is not intended to limit the present disclosure. Those skilled in the art without departing from the spirit and scope of the present disclosure can make various changes and modifications. Therefore, the protection scope of the present disclosure is defined by the following appended patent claims.

Claims

1. A battery system, comprising: a plurality of unit battery packs, each of the unit battery packs comprising a plurality of battery cells connected in series with each other, and the unit battery packs connected in series with each other; a master switch connected in series with the unit battery packs; a current measuring unit connected in series with the unit battery packs, adapted to measure a measured system current value of the unit battery packs; a plurality of slave units respectively electrically connected to the unit battery packs, each of the slave units adapted to obtain a physical parameter value of each of the battery cells in the corresponding unit battery pack; a master control unit communicatively connected to the slave units and adapted to: control the master switch to be turned off when an abnormality judged from the physical parameter value or the measured system current value is a system abnormality; and execute a processing procedure of the abnormality when the abnormality judged from the physical parameter value or the measured system current value is a detection abnormality, while maintaining the master switch to be turned on, wherein the processing procedure excludes a procedure of controlling the master switch to be turned off.

2. The battery system of claim 1, wherein the master control unit and the slave units are communicatively connected in series, the slave units comprising a first slave unit and a second slave unit, the first slave unit and the second slave unit respectively disposed at opposite ends of the slave units connected in series; the master control unit further comprising: a first communication switch coupled to the first slave unit and adapted to turn on or turn off communication with the first slave unit; a second communication switch coupled to the second slave unit and adapted to turn on or turn off communication with the second slave unit; and a communication control unit coupled to the first communication switch and the second communication switch, the communication control unit adapted to turn on the first communication switch and the second communication switch alternately to obtain a return signal of all the slave units.

3. The battery system of claim 1, wherein the master control unit is further adapted to: request a charger to provide a first test current to the battery system; judge whether a first current difference absolute value between a first test current value of the first test current and the measured system current value is greater than a permissible current error; and when the first current difference absolute value is greater than the permissible current error, judge whether an electric storage amount of the battery system is equal to or higher than a safety value; when the electric storage amount of the battery system is lower than the safety value, control the master switch to be turned on so that the charger charges the battery system until the electric storage amount of the battery system reaches the safety value; and when the electric storage amount of the battery system is equal to or higher than the safety value, control the master switch to be turned off; the first test current value refers to a current value measured by the charger, and the measured system current value refers to a current value measured by the current measuring unit in the battery system.

4. The battery system of claim 3, wherein the master control unit is further adapted to: wherein request the charger to provide a second test current to the battery system, wherein the second test current is substantially higher than the first test current; judge whether a second current difference absolute value between a second test current value of the second test current and the measured system current value is greater than the permissible current error; and when the second current difference absolute value is greater than the permissible current error, judge whether the electric storage amount of the battery system is equal to or higher than the safety value. ​ determining whether the battery system has an electrical storage amount equal to or higher than the safety value when either of the first current difference absolute value and the second current difference absolute value is greater than the allowable current error; controlling the total switch to be turned on when the electrical storage amount of the battery system is lower than the safety value, so that the charger charges the battery system until the electrical storage amount of the battery system reaches the safety value; and controlling the total switch to be turned off when the electrical storage amount of the battery system is higher than the safety value. wherein, The second test current value is a current value measured by the charger.

5. The battery system of claim 1, wherein each of the slave units further comprises: a first battery switch and a second battery switch respectively switchably connected to or disconnected from two ends of a measured battery cell of the battery cells; a slave voltage measurer electrically connected to the measured battery cell and adapted to measure a first measured voltage of the measured battery cell; a comparison voltage measurer electrically connected to the first battery switch and the second battery switch and adapted to measure a second measured voltage of the measured battery cell; and a slave controller coupled to the slave voltage measurer and the comparison voltage measurer, the slave controller adapted to: control the first battery switch and the second battery switch to electrically connect the measured battery cell to the comparison voltage measurer; determine whether a voltage difference absolute value between the first measured voltage of the measured battery cell and the second measured voltage measured by the comparison voltage measurer is greater than an allowable voltage error; and output an abnormality detection signal to the master unit when the voltage difference absolute value is greater than the allowable voltage error. wherein the first measured voltage is a voltage value of the measured battery cell measured by the slave voltage measurer, and the second measured voltage is a voltage value of the measured battery cell measured by the comparison voltage measurer.

6. The battery system of claim 1, wherein each of the slave units further comprises: a plurality of battery switch groups, each of the battery switch groups comprising: a first battery switch; and a second battery switch, and each of the battery cells is electrically connected to the battery switch group, wherein the first battery switch and the second battery switch are respectively switchably connected to or disconnected from two ends of a corresponding battery cell; a slave voltage measurer electrically connected to the battery cells and adapted to measure a first measured voltage of each of the battery cells; a comparison voltage measurer electrically connected to the first battery switches and the second battery switches and adapted to measure a second measured voltage of each of the battery cells; and a slave controller coupled to the slave voltage measurer and the comparison voltage measurer, the slave controller adapted to: alternately control each of the battery switch groups to alternately electrically connect each of the battery cells to the comparison voltage measurer; determine whether a voltage difference absolute value between the first measured voltage of each of the battery cells and the second measured voltage is greater than an allowable voltage error; output an abnormality detection signal to the master unit when the voltage difference absolute value is greater than the allowable voltage error. wherein the first measured voltage is a voltage value of each of the battery cells measured by the slave voltage measurer, and the second measured voltage is a voltage value of each of the battery cells measured by the comparison voltage measurer.

7. The battery system of claim 6, wherein each of the slave units further comprises: a first bus bar connected to the first battery switches; and a second bus bar connected to the second battery switches; wherein the first bus bar and the second bus bar are electrically connected to the comparison voltage measurer.

8. The battery system of claim 1, further comprising: an indicator coupled to the master unit, the indicator adapted to output a detection abnormality alarm signal when a detection abnormality occurs.

9. A protection method for a battery system, the battery system being the battery system of claim 1, the protection method comprising: the current measurer measuring the measured system current value of the cell groups; each of the battery core measurers measuring the physical parameter value of each of the battery cores in each of the cell groups; when an abnormality judged from the physical parameter value or the measured system current value is the system abnormality, the master unit controlling the main switch to be turned off; and when an abnormality judged from the physical parameter value or the measured system current value is the detection abnormality, the master unit executing a processing procedure of the detection abnormality while maintaining the main switch to be turned on, wherein the processing procedure excludes a procedure of controlling the main switch to be turned off.

10. The protection method of claim 9, wherein the physical parameter value is a measured voltage value or a measured temperature value detected by each of the battery cores; the protection method further comprising: the slave unit obtaining the measured system current value; the slave unit judging whether an abnormality occurred in the battery system is the system abnormality or the detection abnormality according to the measured voltage value, the measured temperature value, and the measured system current value.

11. The protection method of claim 10, further comprising: the slave unit judging whether the measured temperature value of a measured battery core of the battery cores increases sharply within a unit time; when the measured temperature value of the measured battery core increases sharply within the unit time, the slave unit judging whether the measured temperature values of the battery cores adjacent to the measured battery core increase synchronously; and when the measured temperature values of the adjacent battery cores increase synchronously, the slave unit judging that the abnormality occurred in the battery system is the system abnormality.

12. The protection method of claim 10, further comprising: the slave unit judging whether a variation amplitude of the measured voltage value of a measured battery core of the battery cores within a unit time exceeds a limit value; when the variation amplitude of the measured voltage value of the measured battery core within the unit time exceeds the limit value, the slave unit judging whether the measured system current value changes synchronously with the measured voltage value of the measured battery core by comparing the measured system current value broadcasted by the master unit; and when the measured voltage value of the measured battery core changes synchronously with the measured system current value, the slave unit judging that the abnormality occurred in the battery system is the system abnormality.

13. The protection method of claim 10, further comprising: ​ When the battery system is in a discharging state, the measured system current value suddenly becomes zero without a corresponding change in the measured voltage value of each battery cell, the slave control unit determines that the abnormality occurring in the battery system belongs to the detection abnormality.

14. The protection method of claim 10, further comprising: the slave control unit determining whether the measured temperature value of the measured battery cell of the battery cells suddenly increases; when the measured temperature value of the measured battery cell suddenly increases, determining whether the measured temperature values of the battery cells adjacent to the measured battery cell simultaneously suddenly increase; and when the measured temperature values of the adjacent battery cells do not simultaneously suddenly increase, determining that the abnormality occurring in the battery system belongs to the detection abnormality.

15. The protection method of claim 10, further comprising: when the change in the measured voltage value of the measured battery cell of the battery cells is inconsistent with the change in the measured voltage value of another of the battery cells, and the measured system current value simultaneously changes corresponding to the measured voltage value of the another of the battery cells, the slave control unit determines that the abnormality occurring in the battery system belongs to the detection abnormality.

16. The protection method of claim 10, further comprising: when the change in the physical parameter value of the measured battery cell of the battery cells has an equal offset with the change in the physical parameter value of the other battery cells, the slave control unit determines that the abnormality occurring in the battery system belongs to the detection abnormality.

17. The protection method of claim 10, further comprising: when the physical parameter value of the measured battery cell of the battery cells or the measured system current value does not have a linkage and has an irregular jitter change, the slave control unit determines that the abnormality occurring in the battery system belongs to the detection abnormality.

18. The protection method of claim 10, further comprising: when the measured temperature value of the measured battery cell of the battery cells suddenly increases or decreases at a moment, the slave control unit determines that the abnormality occurring in the battery system belongs to the detection abnormality.

19. The protection method of claim 9, wherein the master control unit is communicatively connected in series with the slave control units, the slave control units include a first slave control unit and a second slave control unit, the first slave control unit and the second slave control unit are respectively disposed at opposite ends of the slave control units in series, the master control unit further includes a first communication switch, a second communication switch, and a communication control unit, the first communication switch is coupled to the first slave control unit, the second communication switch is coupled to the second slave control unit, and the communication control unit is coupled to the first communication switch and the second communication switch. The protection method further comprises: the first communication switch turns on or off the communication with the first slave control unit; the second communication switch turns on or off the communication with the second slave control unit; and the communication control unit turns on the first communication switch and the second communication switch alternately.

20. The protection method of claim 9, further comprising: the master control unit requiring a charger to provide a first test current to the battery system; determining whether a first current difference absolute value between a first test current value of the first test current and a corresponding measured system current value is greater than an allowable current error; and when the first current difference absolute value is greater than the allowable current error, the master control unit determines whether the electric storage amount of the battery system is equal to or higher than a safety value; when the electric storage amount of the battery system is lower than the safety value, the master control unit controls the total switch to turn on, so that the charger charges the battery system until the electric storage amount of the battery system reaches the safety value; and when the electric storage amount of the battery system is equal to or higher than the safety value, the master control unit controls the total switch to turn off. wherein the first test current value is a current value measured by the charger, and the measured system current value is a current value measured by the current measurement unit in the battery system.

21. The protection method of claim 20, further comprising: the master control unit requiring the charger to provide a second test current to the battery system, wherein the second test current is substantially higher than the first test current; determining whether a second current difference absolute value between a second test current value of the second test current and the measured system current value is greater than the allowable current error; when either the first current difference absolute value or the second current difference absolute value is greater than the allowable current error, the master control unit determining whether the state of charge of the battery system is equal to or higher than the safety value; when the state of charge of the battery system is lower than the safety value, the master control unit controlling the main switch to be on, so that the charger charges the battery system until the state of charge of the battery system reaches the safety value; and when the state of charge of the battery system is higher than the safety value, the master control unit controlling the main switch to be off. wherein the second test current value is a current value measured by the charger.

22. The protection method of claim 14, further comprising: when the detected abnormality does not affect the safety and reliability of the battery system, the master control unit ignoring the detected abnormality.

23. The protection method of any one of claims 13 and 15-18, further comprising: when the battery system is in a non-use state, the master control unit controlling the main switch to be off.

24. The protection method of any one of claims 13 and 15-18, further comprising: when the battery system is in a use state, the master control unit reducing the output of the system current value.

25. The protection method of any one of claims 13 and 15-18, further comprising: when the battery system is in a use state, the master control unit starting a power-off countdown mode.

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