TWI620392B - Battery control system and method for determining state of health without unnoticed battery shut down - Google Patents

Abstract

In one embodiment, a battery control system includes: a plurality of battery cells, the plurality of battery cells including a battery system; and a controller coupled to the plurality of battery cells, the controller Configuring a first voltage and a second voltage for each of the battery cells, the first voltage corresponding to an absolute value of a disconnected voltage, and the second voltage corresponding to a warning voltage, the first voltage being The second voltage is small, wherein in response to one of the battery cells reaching the second voltage, the controller is configured to provide a first alarm before any of the battery cells reaches the first voltage.

Description

Battery control system and method for determining health status without unnoticed battery shutdown

This disclosure is generally related to determining the health of the battery while avoiding unattended battery shutdown.

The health of the battery is important for electric bicycles, electric cars, electric vehicles, electric pushers, and energy storage systems that require a wide range of dynamic and dynamic battery energy sources. A suitable mechanism that does not include a determination of the health of the battery can result in an unattended shutdown (or failure) of the battery system during service. In general, unobstructed shutdown of battery systems results from the fact that one of the series connected batteries (or battery packs) has a smaller capacity or higher resistance. This problem is particularly acute in lithium-ion battery systems because an absolute cut-off voltage is typically set for each of the series connected batteries (or battery packs). A context in which shutdown of the battery system can be unnoticed is achieved when one of the series connected batteries (or battery packs) reaches a cut-off condition before reaching a lower cut-off voltage of the battery system. In this case, the battery system can be turned off without paying attention.

On the other hand, it is not easy without complicated and procrastinating processes. The decision to implement a state of health. For example, separately exploring individual battery or battery pack capacities involves cycling each battery. This is a long and complicated process that cannot be implemented daily, and thus increases the risk of unattended shutdown of the battery system during the user's daily operations.

In one embodiment, a battery control system includes: a plurality of battery cells, the plurality of battery cells including a battery system; and a controller coupled to the plurality of battery cells, the controller Configuring to monitor a first voltage and a second voltage for each of the battery cells, the first voltage corresponding to an absolute value of a shut-off voltage, and the second voltage corresponding to a warning voltage ( Warning voltage), the first voltage being smaller than the second voltage, wherein one of the battery cells that reaches the second voltage, the controller is configured to reach the first one of the battery cells A first alarm is provided before the voltage.

10, 10A‧‧‧ battery system

12, 14, 16, 18, 20, 22, 24, 26‧‧‧ battery cells

28, 34‧‧‧Multiple battery cells

30, 30A, 36, 44‧‧ ‧ controller

32, 38‧‧‧ load

40, 42‧‧‧ modules

10B, 10C‧‧‧ battery control method

46, 48, 50, 52, 54, 56, 60, 62, 64, 66, 68 ‧ ‧ steps

Many aspects of the systems and methods of the present disclosure may be better understood by reference to the following drawings. The elements in the figures are not necessarily to be Further, in the drawings, like element symbols indicate corresponding parts in several views.

1A is a block diagram showing an exemplary battery system implementing one embodiment of a battery control system.

1B is a block diagram showing another example battery system implementing one embodiment of a battery control system.

Figure 2 is a flow chart showing an implementation of the battery control method example.

Fig. 3 is a flow chart showing another embodiment of the battery control method.

Fig. 4 is a diagram showing an example of a battery control method for an electric golf cart.

Disclosed herein are certain embodiments of the invention relating to battery control systems and methods that are capable of determining battery health and preventing unintentional shutdown of the battery. In one embodiment, the battery control system includes one or more controllers to monitor a plurality of voltages of each battery of the battery system, including absolute cutoff voltages and warning voltages, and alerting the user to an imminent occurrence in the battery system shut down. In other words, certain embodiments of the battery control system alert the user (in some embodiments or to the device, such as when automatic control is required) to take certain actions in response to one or more batteries that reach the warning voltage, Therefore, one or more batteries are prevented or prevented from reaching an absolute cut-off voltage. In some embodiments, the battery control system also provides a health status decision, as described further below.

Briefly, traditional systems typically operate in a system-closed, unnoticed manner, as described above. In addition to the unnoticed shutdown of the battery system, the identification of the health status of a series connected battery or a plurality of batteries (or battery packs) having a smaller capacity is also important. For example, assume that an electric car typically travels 50 miles per charge. If the total number of miles is shorter than expected, it is important for the alerting user to prevent sudden, unnoticed battery shutdowns as a first priority and to inform the user if the battery system is healthy. Provide this level With lower charge capacity and battery (or battery pack) health status information, users can avoid unattended closure risks and, at the same time, urge users to implement appropriate actions such as battery maintenance. In certain embodiments of the present disclosure, the introduction of a simple and feasible method and apparatus (and system) for monitoring battery health can be implemented in everyday (regular) without unnoticed battery shutdown.

Summarizing certain features of the battery control system of the present disclosure, reference is now made to the details of the specification of the present disclosure, as illustrated in the drawings. The present disclosure is described in connection with the drawings, and is not intended to limit the invention to the embodiments disclosed herein. Further, although the specification identifies or describes a particular embodiment of one or more embodiments, such a particular embodiment is not an essential part of every embodiment, and is not necessarily all of the various stated advantages necessarily associated with a single embodiment. In addition, all the selections, modifications, and equivalents are intended to be included in the spirit and scope of the invention as defined by the appended claims. Further, it should be understood from the disclosure of the present disclosure that the scope of the patent application is not necessarily limited to the specific embodiments set forth in the specification.

Note that the reference to the battery here refers to a single battery cell, and the reference of the battery cell group (or battery pack) here refers to several battery cells connected in parallel. To facilitate the understanding of the following description, the battery cells used herein are considered to be battery cells or battery cell groups. Further, note that the reference to the modules herein refers to battery cells connected in series and/or in parallel (for example, a 13.3V 40Ah lithium iron battery includes one module consisting of four battery cell groups connected in series, each group consisting of four Parallel 10Ah battery cell composition). The battery system used here refers to a battery module connected in series and in parallel. All of the above terms will be used throughout this disclosure.

Referring now to Figure 1A, there is shown a diagram of implementing a battery control system. A block diagram of an exemplary battery system 10 of an embodiment. In the context of the present disclosure, it is understood that the battery system 10 described in the 1A (and 1B) diagrams is merely illustrative, and other battery systems having different component arrangements may be used and may be combined. Certain embodiments of battery control systems. Battery system 10 includes a plurality of battery cells, including battery cells 12-26, disposed in series as depicted in FIG. 1A. A plurality of battery cells 12-26 can be generally represented as component symbols 28. To facilitate an understanding of various embodiments of the battery control system, assuming battery unit 28 is embodied in a battery bay, it will be appreciated that in some embodiments battery unit 28 may be embodied in a battery pack. Further, in this example a plurality of battery cells 28 collectively define a single module. Battery system 10 further includes a controller 30 coupled to each of a plurality of battery cells 28. A plurality of battery cells 28 are also coupled in series with the load 32. In one embodiment, the battery control system includes a controller 30 and a plurality of battery cells 28, even though some embodiments may include fewer or additional components. In some embodiments, the module and controller 30 can be packaged as the same integrated device, and in some embodiments, the module and controller can be coupled but separated.

In the embodiment depicted in FIG. 1A, controller 30 is operative to monitor the voltage of each of battery cells 12-26 connected in series. For each of the battery cells 12-26, two voltages are monitored: the first voltage is an absolute cutoff voltage and the second voltage is a warning voltage, the second voltage being higher than the first voltage. Note that for battery cells configured as battery packs, monitoring the group can be performed with only a parallel arrangement of given battery packs. At the same time, the total voltage of all series connected battery cells 28 is also monitored as the system voltage. The use of a car is an example environment in which the battery system 10 can be used (it should be understood that other environments can use the battery system 10) in the battery During discharge of system 10, if the second voltage is reached, a first alarm (e.g., a signal) is transmitted to the user or the car via a buzzer, light, or any analog or digital mechanism. At this point, the user or car should reduce the load 32 (eg, reduce speed or motor revolutions per minute) to prevent the first alarm from being continuously generated. If the load reduction does not prevent the first alarm from being continuously generated, this condition is referred to as an "end" discharge. At this point, the system voltage (eg, monitored at the battery module) can be used to determine the health of the battery cells 28 connected in series. If the voltage is still higher than the system voltage, meaning that the system voltage has not been reached (eg, typically the system voltage is greater than the second voltage multiplied by the number of battery cells 28 connected in series), meaning that one of the battery cells 28 connected in series is The lower capacity, forcing the battery system 10 to end the duty cycle. In this case, a second alert is generated (or indicated) "need to be maintained" and transmitted to the user or car via any mechanism, such as a buzzer, a light, or any analog or digital form of sound. In contrast to the above, if the system voltage is reached before the first first alarm, or if the system voltage is reached or exceeded (ie, below the system voltage) when the first alarm is continuous, no "maintenance required" alarm will be generated. .

FIG. 1B is a block diagram showing another exemplary battery system 10A that implements an embodiment of a battery control system. Again assuming that each battery cell has a single battery cell (it is understood that in some embodiments the battery cell can also be a battery cell bank), the example battery system 10A includes some of the similar features as shown in Figure 1A. For example, a plurality of battery cells 28 are shown connected in series, and each battery cell 28 is monitored by controller 30A to detect the first and second voltages. Also shown in FIG. 1B is a plurality of battery cells 34 arranged in series, with the controller 36 monitoring the first and second voltages of each of the battery cells 34. Multiple battery sheets The elements 28 and 34 are coupled together in series, each of which is also coupled to the load 38. A plurality of battery cells 28 include a module 40, and a plurality of battery cells 34 include another module 42. In some embodiments, module 40 and controller 30A (and module 42 and controller 36) can be packaged in the same integrated device. In some embodiments, module 40 and controller 30A can be packaged as one integrated device, and module 42 and controller 36 can be packaged in the same integrated device as integrated device including module 40 and controller 30A. In some embodiments, the module and controller can be coupled but separate devices. Unlike controller 30 in the first example of FIG. 1A, controllers 30A and 36 in FIG. 1B are not configured to monitor health status and system voltage. Note that in some embodiments, controllers 30A and 36 can be configured to monitor health status and system voltage, but are not operated in this manner (eg, functional passivation or failure). Controller 44 is included in example battery system 10A and is configured to monitor load 38 and then system voltage to provide a determination of health status (eg, a problem of insufficient capacity). Controllers 30A, 36, and 44 communicate (e.g., via wired or wireless media) with one another (e.g., via a wired or wireless medium) when one or more of battery cells 28 and 34 reach a warning voltage to provide an alerting user or device ( For example, the function of a car, and this behavior is performed before the cut-off voltage is reached (if it occurs, which can lead to unattended shutdown or failure). In other words, using the battery control system as described in Figures 1A-1B, the first voltage is not expected to be externally achieved. The battery unit capacity information (capacity or capacity information between the second voltage and the first voltage, unlike the capacity used in the prior art portion of the present disclosure, with reference to a shortage of knowledge or indication) enables the user or device to The appropriate action is performed before the battery system 10 (or 10A) is turned off. For example, in the case of a series hybrid electric vehicle, the generator (usually powered by an internal combustion engine) can be powered Raised before pool system 10 or 10A is shut down.

Note that controllers 30, 30A, and 36 are used to each monitor (e.g., detect) the first and second voltages of each of a plurality of battery cells 28 and 34, and controllers 44 (and 30) are used The system voltage is monitored and the health status of each of the plurality of battery cells 28 and 34 connected in series is determined. In some embodiments, controllers 30A and 36 can be configured to monitor the module voltage for comparison with the system voltage monitored by controller 44. In some embodiments, the controller 44 can be coupled or integrated with a module of one or more battery cells, and the battery control system can monitor each battery cell (eg, battery bay or group) and include several Such battery module voltage comparisons (or in some embodiments, controller 44 does not include one or more battery modules) are implemented in each battery module.

In one embodiment, controllers 30, 30A, 36, and 44 (and in some embodiments one or more battery modules) may all be integrated into a single integrated device, such as an integrated circuit other than other packaged units ( IC), microprocessor unit (MCU), or programmable logic controller (PLC). In some embodiments, each of the controllers 30, 30A, 36, and 44 can be separate and separate package units. In other words, the overall voltage detection and decision of the health state (eg, implemented by controller 44) can be performed by a separate IC, MCU, or PLC (ie, separate from controllers 30A and 36). Any device or system for battery cell voltage monitoring and overall battery system monitoring to prevent unnoticed battery shutdown and health status determinations is considered to be within the scope of the present disclosure.

In view of the above description, several observations can be made, including the following: (a) During the above battery control process, the battery can be monitored and diagnosed during daily operation. (b) The above-described battery control system and method can be implemented locally in each battery module to avoid complex sensors, data transfer, and/or extension calculations required to monitor the state of charge of the battery; c) The simplicity of the battery control system described herein enables the automotive (or device) electrical control unit (ECU) to operate more reliably and efficiently than conventional systems. For example, in some embodiments, only the data to be transmitted may be specifically "slow down" (eg, related to the first alert) or "need to be maintained" (eg, related to the second alert); and (d The battery control system uses only voltage detection to achieve both "preventing unattended battery system shutdown" and "health status determination". In general, certain embodiments of battery control systems are simple and reliable, and can be applied to any application requiring a large and dynamic source of power.

It should be understood in the context of this disclosure that certain embodiments of battery control systems and methods can be implemented in each battery module that monitors each battery cell (eg, battery bay or group) and compared to the module voltage, Alternatively, it can be implemented in a battery system that includes a battery control system that monitors each battery module voltage and compares it to the battery system voltage. In some embodiments, the battery control system and method can monitor the voltage of each battery cell (eg, a battery well or group) and compare it to a battery system voltage comprising a plurality of such battery modules, in each battery mode. Implemented in the group.

In view of the above description, it should be understood that a battery control method 10B as described in FIG. 2 and implemented by one or more controllers includes monitoring each of a plurality of battery cells (eg, a battery bay or The battery pack (46), and determines whether any of the plurality of battery cells includes a voltage (48) that reaches a relevant warning voltage. If not, continue monitoring (for example, back to monitoring 46). in case If any of the plurality of battery cells is equal to the warning voltage ("Yes"), a first alarm (alarm #1) (50) is provided, which may include or be associated with an instruction to reduce the load (eg, reduce) Speed or car revolutions per minute). The battery control method 10B further determines whether the first alarm is removed in response to the load reduction (52). If YES, the process returns to the monitoring (46). If "No", the situation corresponds to the end of the discharge. The treatment continues until the overall system health is monitored (54). The decision of whether or not the system voltage is reached is made by control method 10B (56). For example, as previously described, flow (56) involves determining if the voltage falls below or below the system voltage. If YES, the battery control method 10B quits or inhibits the transmission of an alarm (62), otherwise, provides a second alarm (e.g., alarm #2) (60). In other words, if the system voltage is reached before the first first alarm, or if the system voltage is reached or exceeded (ie, below the system voltage) when the first alarm is continuous, then a "need to maintain" alarm will not be generated. Note that when this alert is issued, it may accompany or contain a message that requires maintenance.

Another method embodiment, represented as battery control method 10C and shown in FIG. 3, includes monitoring, in a controller, each battery cell (64) between a plurality of battery cells of a battery system, determining the battery cells Whether any of them is equal to a warning voltage, the warning voltage set for each battery unit is higher than the absolute cut-off voltage of each battery setting (66); and the battery unit that responds to the warning voltage And providing a first alarm to reduce a load (68) coupled to the plurality of battery cells before any one of the plurality of battery cells reaches the absolute cutoff voltage.

Some examples may be helpful in illustrating some example operations of using a battery control system as disclosed herein. It should be understood that the numerical values used in these examples are merely illustrative and other values may be obtained as appropriate. In one example, reference is made to Example 1, assuming a battery system implemented in a golf cart that is equipped with two modules in series. Each module contains 8 battery cells in series with a series of battery cells, and each battery cell group contains 8 8Ah batteries placed in parallel. This example uses a lithium iron battery. It is understood by those of ordinary skill in the art that a lithium iron battery refers to a LiFePO ₄ or a non-stoichiometric form of LiFePO ₄ as a positive electrode material, for example, as disclosed in: US 7,494,744 (B2), US 7,585,593 (B2), US 7,629,084 ( B2), and the battery of US 7,718,320 (B2). In each battery module, a controller is used to monitor the eight battery cell groups in series. For each battery pack, the second voltage (eg, the warning voltage) is set to 2.8V and the first voltage (eg, the cutoff voltage) is set to 2.0V. In this example the system voltage is monitored and set to 48V. Figure 4 shows the results of a test run for a continuous distance of 22 km (equivalent to 13.8 miles).

Note that in Figure 4, a continuous buzzer sound is observed during the test run to approximately the point marked "Minimum Voltage 45.59 during Discharge." At this time, because 45.59V is lower than the preset system voltage of 48V, no "maintenance required" alarm (for example, a message) will be generated. This means that the battery cells are substantially identical in capacity, so the overall voltage is lower than the preset system voltage of 48V. In other words, the voltage reading of 45.59 is achieved because one of the battery slots reaches 2.8V and the other battery slot group contributes 45.59-2.8 = 42.79V. If the remaining 15 battery packs averaged 42.79, each battery pack contributed 2.85V, which is very close to the value that triggered the 2.8V alert. If one of the slot groups reaches 2.8V when the system voltage is 50V (higher than the system preset voltage of 48V), the average of the remaining 15 battery packs (50-2.8=47.2V) is 47.2/15=3.15V. ,versus 2.8V is very different, so "maintenance required" should be generated. It is worth noting that the system voltage may not reflect the true individual battery voltage. It is more reliable to use the individual battery voltage (second voltage) as the basis for the first warning and to use the system voltage for the health of the battery.

As another example, the contents of the electric vehicle will be described with reference to Example 2, using the TOYOTA® COMS electric vehicle as an example. The battery system implemented in COMS consists of three modules connected in series. Each module contains 8 battery cells configured in a series group and each battery pack contains 5 parallel 10Ah batteries. The lithium iron battery was used again in this example. In each battery module, a controller is used to monitor eight battery packs connected in series. For each battery pack, the second voltage was set to 2.8 V and the first voltage (cutoff voltage) was set to 2.0V. In this example the system voltage is monitored and set to 72V. After 64.7km of driving, the buzzer began to make a sound. At this time, the driving speed was reduced to 20 km/hr, and no sound was generated. After a further 4km of driving, the car began to make a continuous sound. At this time, there is no "maintenance required" signal, and the battery module voltage is measured to be 21.3V, 24.16V, and 23.72V, which is lower than the preset system voltage of 72V.

It is believed that the same technique can be used to monitor the three module voltages and compare them to the system voltage. If one of the modules exhibits a lower voltage (eg, 20V) and a warning is generated, and the overall voltage is higher than 72V (eg, 75V), a significant imbalance between the modules can be identified because the other two modules should With an average voltage (75-20)/2 = 27.5V, a "need to be maintained" alarm (eg, a signal) should be generated to draw the user's attention.

In another example, reference is made to Example 3, using an uninterruptible power system (UPS) as an example environment for an embodiment of a battery control system. In this example, A 3 kW UPS was used as an example. The battery system implemented in the UPS consists of only one module. The module contains 16 battery packs in series, each battery pack containing four 10Ah parallel batteries (2kWh modules). The lithium iron battery is used again in this example. In the battery module, two controllers are used to monitor 16 battery packs connected in series (each having 8 channels). For each battery pack, the second voltage was set to 2.8 V and the first voltage (cutoff voltage) was set to 2.0V. In this example, the system voltage is monitored and set to 48V for warning. Observed that if one of the battery packs discharges 20% better than the other battery packs, and the second voltage (2.8V) warning is turned off, the 48V warning may be before the first voltage (2.0V, battery cut-off voltage) causes the system to shut down. Unable to make a sound. This demonstrates the failure of using the system voltage alone as a warning. Since the traditional UPS operating system: when the system voltage is lower than 48V, it will be turned off when the system voltage is lower than 45V; therefore, it is ideal to notify the user to combine other warnings generated by the second voltage before the system is turned off. If the second voltage warning continues to sound before the preset system voltage warning (48V) is reached, it is determined that the health status of the battery pack is NG and "maintenance required" should be generated to attract the user's attention.

It is noted that the scope of the present disclosure may include other embodiments, and the functions associated with the presentation or discussion of Figures 2 through 3 may be performed in other sequences, including substantially simultaneous or reverse order, depending on the functionality involved, the field to which the invention pertains. Those with ordinary knowledge can understand.

It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementation, and are merely illustrative of the principles of the battery control system and method embodiments. Many variations and modifications may be made to the above-described embodiments without departing from the spirit and principles. All such amendments and changes are intended to be included in this disclosure. It is protected by the scope of the following patent application.

Claims (16)

A battery control system includes: a plurality of battery cells, the plurality of battery cells including a battery system; and a controller coupled to the plurality of battery cells, the controller configured to The battery unit monitors a first voltage and a second voltage, the first voltage corresponds to an absolute value of a shut-off voltage, and the second voltage corresponds to a warning voltage. a voltage that is less than the second voltage, wherein one of the battery cells that reaches the second voltage, the controller is configured to provide a first time before any of the battery cells reaches the first voltage An alarm; wherein the controller is further configured to initiate an instruction to reduce a load in response to the first alarm, wherein the controller is further configured to monitor the battery system if the first alarm is not stopped by the reduction in the load One of the health conditions; wherein a system voltage is not reached in response to the battery system, the controller avoids issuing a second alarm, otherwise the controller is configured to provide a second alarm . The system of claim 1, wherein each of the battery cells comprises a battery cell. The system of claim 1, wherein each of the battery cells comprises a battery set. The system of claim 1, wherein the controller is configured to provide the first and second alerts in the form of: an audible, visual, or tactile event, or two of the auditory, visual, and tactile events or A combination of more. The system of claim 1, further comprising a second controller communicatively coupled to the controller and configured to monitor a system voltage, wherein the plurality of battery cells include one or In more modules, the plurality of battery cells are configured to be connected in parallel and in series, wherein the second controller and the first controller are packaged as a single integrated device. The system of claim 5, wherein the controller is further configured to generate an instruction to reduce a load in response to the first alarm, wherein the second controller cannot be stopped if the load is reduced, the second controller It is further configured to monitor the health of one of the battery systems. The system of claim 6, wherein the controller or the second controller avoids issuing a second alarm in response to the system voltage of the battery system, otherwise the controller or the second controller Configured to provide a second alert. The system of claim 7, wherein the controller or the second controller is configured to provide the first and second alerts in the form of: an auditory, visual, Or a tactile event, or a combination of two or more of the auditory, visual, and tactile events. The system of claim 7, wherein the second alert corresponds to a message that needs to be maintained. The system of claim 1, wherein each of the battery cells comprises a lithium ion based battery. A battery control method includes: in a controller: monitoring each battery unit between a plurality of battery units of a battery system; determining whether any of the battery units is equal to a warning voltage, for each battery The warning voltage set by the unit is higher than the absolute cut-off voltage of one of the battery settings; and one of the battery cells that reaches the warning voltage reaches one of the plurality of battery cells Providing a first alarm to reduce a load coupled to the plurality of battery cells before the absolute cutoff voltage; and providing an instruction to reduce the load in response to the first alarm, wherein if the load is reduced Stopping the first alarm, monitoring a health status of the battery system; wherein a system voltage in response to the battery system is not reached, avoiding issuing a second alarm, otherwise providing the second alarm. The method of claim 11, wherein the first and second alerts have the form of an audible, visual, or tactile event, or a combination of two or more of the auditory, visual, and tactile events. The method of claim 12, wherein the first alert includes an instruction to reduce a load in response to the first alert, wherein if the load is reduced, the first alert cannot be stopped, further comprising monitoring: A second controller coupled to the device monitors a health status of the battery system. The method of claim 13 wherein in response to the non-system voltage of the battery system, a second alarm is avoided, otherwise the second alarm is provided. The method of claim 14, wherein the first and second alarms have the form of: an audible, visual, or tactile event, or a combination of two or more of the auditory, visual, and tactile events, and The second alarm corresponds to a piece of information that needs to be maintained. A battery control system comprising: a plurality of battery modules, the plurality of battery modules being coupled to a load, each of the battery modules comprising battery cells arranged in series and in parallel, the batteries of a battery system a module portion; and a plurality of controllers in the battery system, each of the plurality of controls Individually coupled to the plurality of battery modules, the plurality of controllers configured to monitor a first voltage and a second voltage for each battery of each module, the first voltage corresponding to a disconnection An absolute value of the voltage, and the second voltage corresponds to a warning voltage, the first voltage being smaller than the second voltage, wherein one of the battery cells that reaches the second voltage is in the battery unit One or more of the plurality of controllers are configured to provide a first alert prior to the first voltage being reached, wherein the one or more of the plurality of controllers are further configured to cause a The command reduces the load in response to the first alarm, wherein if the first alarm is unable to stop the first alarm, the one or more of the plurality of controllers are accumulated in the plurality of battery modules The voltage is less than a predetermined system voltage of the battery system, and is further configured to avoid providing a second alarm corresponding to a message to be maintained, wherein the plurality of controllers are included in a single integrated device in