KR102592332B1 - Battery management system, battery pack and method for charging battery - Google Patents

Abstract

This disclosure relates to battery management systems, battery packs, and battery charging methods. A battery management system according to an embodiment of the present disclosure includes a sensing unit that measures the voltage of a battery module; and a control unit that determines whether the measured voltage is higher than the reference voltage for determining whether the battery module is overvoltage and continues for more than a reference time. The control unit estimates the SOH of the battery module and determines the reference voltage and the reference time based on the estimated SOH.

Description

Battery management system, battery pack and battery charging method {BATTERY MANAGEMENT SYSTEM, BATTERY PACK AND METHOD FOR CHARGING BATTERY}

The present invention relates to a battery management system, a battery pack, and a battery charging method. More specifically, it relates to a battery management system that protects a battery from overvoltage, a battery pack, and a battery charging method.

Recently, as the demand for portable electronic products such as laptops, video cameras, and portable phones has rapidly increased, and as the development of electric vehicles, energy storage batteries, robots, and satellites has begun, the need for high-performance batteries capable of repeated charging and discharging has increased. Research is actively underway.

Currently commercialized batteries include nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries, and lithium secondary batteries. Among these, lithium batteries have little memory effect compared to nickel-based batteries, so they can be freely charged and discharged, and have a low self-discharge rate. It is attracting attention due to its extremely low and high energy density.

SOH (State Of Health) is a parameter that quantitatively indicates the change in capacity that occurs as the battery is used. SOH can generally be expressed as a percentage of the full charge capacity to the design capacity. Full charge capacity represents the maximum amount of charge that the battery can actually accommodate, and is different from the fixed value design capacity in that it gradually decreases as the number of charge and discharge cycles of the battery increases.

There are many different ways to estimate SOH. For example, there are methods for estimating SOH using the internal resistance and temperature of the battery, methods for estimating SOH through a full discharge test, etc.

SOH can be used as an indicator of how much the battery capacity has decreased compared to the initial design capacity, that is, how much more the battery can be used in the future. For example, the user can check in advance when the battery should be replaced by referring to the SOH of the battery notified by an external device.

Meanwhile, the longer the battery is in an overvoltage state, the more gas is generated due to the decomposition of the electrolyte, and the generated gas increases the internal pressure and temperature of the case that seals the battery, causing swelling of the battery. If this condition continues for a long time, the risk of the battery exploding is quite high. Numerous prior technologies have been disclosed to protect batteries from such overvoltage.

Most conventional technologies simply use a method of determining whether the battery is in an overvoltage state based on the results of comparing the battery's voltage with a single, fixed reference value. If the battery is determined to be in an overvoltage state, problems caused by overcharging of the battery can be prevented to some extent by cutting off the power supplied to the battery.

However, as the SOH of the battery decreases, the full charge voltage, which is the voltage of the battery when fully charged, also decreases. However, in the prior art, the overvoltage of the battery is determined based on the above reference value unrelated to the SOH, so the determination of the overvoltage is difficult. Accuracy is bound to drop. Therefore, it is necessary to appropriately adjust the standard value for determining whether the battery is in an overvoltage state according to the SOH of the battery.

The present invention was made to solve the above problems, and includes a battery management system, a battery pack, and battery charging that determine a standard value for determining whether the battery is in an overvoltage state according to the SOH of the battery. The purpose is to provide a method.

Other objects and advantages of the present invention can be understood from the following description and will be more clearly understood by practicing the present invention. In addition, it will be readily apparent that the objects and advantages of the present invention can be realized by means and combinations thereof indicated in the claims.

A battery management system according to an aspect of the present invention includes a sensing unit that measures the voltage of a battery module; and a control unit that determines whether the measured voltage is higher than the reference voltage for determining whether the battery module is overvoltage and continues for more than a reference time. The control unit estimates the SOH of the battery module and determines the reference voltage and the reference time based on the estimated SOH.

Additionally, the control unit may decrease at least one of the reference voltage and the reference time as the estimated SOH decreases.

Additionally, the sensing unit may further measure the temperature of the battery module. The control unit may determine at least one of the reference voltage and the reference time based on the estimated SOH and the measured temperature.

Additionally, the control unit may decrease at least one of the reference voltage and the reference time as the measured temperature increases.

In addition, it may further include a memory that stores a first lookup table in which a plurality of predetermined SOH sections and a plurality of reference voltages associated with each SOH section are recorded. The control unit may select a reference voltage associated with an SOH section to which the estimated SOH belongs from among the plurality of reference voltages and determine the reference voltage based on the selected reference voltage.

Additionally, a plurality of reference times associated with each SOH section may be further recorded in the first lookup table. The control unit may select a reference time associated with an SOH section to which the estimated SOH belongs from among the plurality of reference times and determine the reference time based on the selected reference time.

Additionally, the memory may store a second lookup table in which a plurality of predetermined temperature sections and a plurality of weights associated with each temperature section are recorded. The control unit may select a weight associated with a temperature section to which the measured temperature belongs from among the plurality of weights, and determine the reference voltage based on the selected reference voltage and the selected weight.

Additionally, the control unit may determine the reference time based on the selected reference time and the selected weight.

Additionally, the control unit may perform a predetermined overvoltage prevention operation when the voltage of the battery module remains above the reference voltage for more than the reference time.

A battery pack according to another aspect of the present invention includes a battery module; a charge/discharge circuit configured to selectively perform charging and discharging operations for the battery module; and a battery management system electrically connected to the battery module and the charging/discharging circuit, and configured to monitor the state of the battery module and control the operation of the charging/discharging circuit. The battery management system estimates the SOH of the battery module, determines a reference voltage and a reference time for determining whether the battery module is overvoltage based on the estimated SOH, and determines whether the voltage of the battery module is the reference voltage. As described above, it is determined whether the voltage of the battery module continues for more than the reference time, and if the voltage of the battery module remains above the reference voltage for more than the reference time, a predetermined overvoltage prevention operation is performed. The charging/discharging circuit stops the charging operation when the overvoltage prevention operation is performed.

A battery charging method according to another aspect of the present invention includes estimating the SOH of a battery module; determining a reference voltage and a reference time for determining whether the battery module is overvoltage based on the estimated SOH; determining whether the voltage of the battery module remains above the reference voltage for more than the reference time; And when the voltage of the battery module remains above the reference voltage for more than the reference time, executing a predetermined overvoltage prevention operation.

In addition, the step of determining the reference voltage and the reference time includes accessing a first lookup table in which a plurality of predetermined SOH sections and a plurality of reference voltages associated with each SOH section are recorded, and the plurality of reference voltages selecting a reference voltage associated with an SOH section to which the estimated SOH belongs; and determining the reference voltage based on the selected reference voltage.

Additionally, a plurality of reference times associated with each SOH section may be further recorded in the first lookup table. In this case, determining the reference voltage and reference time may include selecting a reference time associated with an SOH section to which the estimated SOH belongs from among the plurality of reference times; and determining the reference time based on the selected reference time.

According to an embodiment of the present invention, a standard value for determining whether the battery is in an overvoltage state can be determined according to the SOH of the battery. Accordingly, compared to the above-mentioned conventional technologies, it is possible to further improve the charging efficiency of the battery, slow down the deterioration rate of the battery, and further reduce the risks of swelling and explosion due to overcharging.

Additionally, the accuracy of determining whether the battery is overvoltage can be improved.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the detailed description of the invention described later, so the present invention includes the matters described in such drawings. It should not be interpreted as limited to only .
1 is a diagram schematically showing the functional configuration of a battery management system and a battery pack including the same according to an embodiment of the present invention.
Figures 2a and 2b are graphs showing changes in limit voltage and limit time according to the SOH of the battery module.
3 to 6 are diagrams referenced to explain how the battery management system according to an embodiment of the present invention adjusts the reference voltage and reference time for overvoltage determination according to the SOH of the battery module.
7 and 8 are diagrams referenced to explain how a battery management system according to another embodiment of the present invention adjusts the reference voltage and reference time for overvoltage determination according to the SOH of the battery module.
Figure 9 is a flowchart showing a battery charging method according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, the terms or words used in this specification and claims should not be construed as limited to their usual or dictionary meanings, and the inventor should appropriately define the concept of terms in order to explain his or her invention in the best way. It should be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle of definability.

Accordingly, the embodiments described in this specification and the configurations shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent the entire technical idea of the present invention, so at the time of filing this application, various alternatives are available to replace them. It should be understood that equivalents and variations may exist.

Additionally, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description will be omitted.

Throughout the specification, when a part is said to “include” a certain element, this means that it does not exclude other elements, but may further include other elements, unless specifically stated to the contrary. Additionally, terms such as <control unit> used in the specification refer to a unit that processes at least one function or operation, and may be implemented as hardware, software, or a combination of hardware and software.

Additionally, throughout the specification, when a part is said to be "connected" to another part, this refers not only to the case where it is "directly connected" but also to the case where it is "indirectly connected" with another element in between. Includes.

Hereinafter, a battery management system and a battery pack according to an embodiment of the present invention will be described.

Figure 1 is a diagram schematically showing the functional configuration of a battery management system 100 and a battery pack 1 including the same according to an embodiment of the present invention. In Figure 1, communication lines for transmitting and receiving data are indicated with dotted lines, and power lines for charging and discharging are indicated with solid lines.

Referring to FIG. 1, the battery pack 1 includes a battery module 10, a charge/discharge circuit 20, and a battery management system 100.

The battery module 10 may include a plurality of batteries connected to each other in series or parallel. Of course, the battery module 10 may be composed of only a single battery. At this time, the type of battery is not particularly limited and can be composed of secondary batteries such as rechargeable lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel hydrogen batteries, and nickel zinc batteries. It is obvious that the number of batteries included in the battery module 10 can vary depending on the voltage and capacity required for the battery module 10.

The charging/discharging circuit 20 may include a charging unit 21 that performs a charging operation on the battery module 10 and a discharging unit 22 that performs a discharging operation on the battery module 10 . The charge/discharge circuit 20 may be configured to selectively perform charging and discharging operations for the battery module 10 . The charging unit 21 converts the power supplied from the external device 2 into a form required for the battery module 10 and then supplies it to the battery module 10. Conversely, the discharge unit 22 may convert the power supplied from the battery module 10 into a form required by the external device 2 and then supply it to the external device 2 . The external device 2 may be a charger or a load that consumes power.

For example, the charging unit 21 and the discharging unit 22 are configured to adjust the voltage and current supplied to or from the battery module 10 in response to the PWM signal output from the control unit 120, respectively. It may include a switching element (e.g., MOSFET).

The battery management system 100 is electrically connected to the battery module 10 and the charge/discharge circuit 20. For example, the battery management system 100 may be interconnected with the battery module 10 and the charge/discharge circuit 20 through CAN (Controller Area Network).

The battery management system 100 measures and manages the overall state of the battery module 10 to ensure the safety and reliability of the battery module 10. It is configured to control operations individually. Control operations performed by the battery management system 100 can be largely divided into thermal control operations for cooling the battery module 10 and charge state control operations.

Specifically, the battery management system 100 monitors the status (e.g., voltage, current, and temperature) of the battery module 10 in real time or periodically to maintain the battery module 10 in an optimal state, and maintains the battery module 10 in an optimal state. When an abnormality in (10) or other electronic components electrically coupled thereto is detected, a signal can be output to notify the external device (2) of this abnormality. Of course, it is obvious that signals for separately starting or stopping the charging operation and discharging operation of the battery module 10 can be output.

In particular, the battery management system 100 performs operations to prevent overcharging when charging the battery and to prevent overdischarging when discharging the battery.

This battery management system 100 may basically include a sensing unit 110 and a control unit 120. In some cases, the battery management system 100 may additionally include a cell balancing module.

The sensing unit 110 is configured to basically measure voltage and current of the battery. Depending on its implementation, the sensing unit 110 may be configured to additionally measure the temperature of the battery.

The sensing unit 110 includes a current sensor that measures the charging current supplied to the battery module 10, a voltage sensor that measures the terminal voltage between the positive and negative poles of the battery module 10, and a temperature sensor that measures the temperature of the battery module 10. It may include a temperature sensor.

The current sensor can measure the charging/discharging current of the battery module 10 while the charging process of the battery module 10 is in progress. Additionally, the current sensor may measure the current rate based on the charge/discharge current of the battery module 10. The charge/discharge rate, also called C-rate, is expressed by dividing the discharge current or charge current by the value of the design capacity minus the unit, and the unit of this charge/discharge rate is C. At this time, the design capacity may be a value determined in advance when manufacturing the battery module 10.

For example, if the full charge capacity of the battery module 10 is 1000 mAh (Apere-hour), if the charging current is 100 mA, the charge/discharge rate is 0.1C, if the charge current is 1000 mA, the charge/discharge rate is 1C, and the charge current is 5000 mA. If so, the charge/discharge rate can be measured at 5C.

The sensing unit 110 can repeatedly measure the current, voltage, and temperature of the battery module 10 at predetermined cycles, and the measurement cycle for any one of the current, voltage, and temperature is the same as or different from the measurement cycle for the others. can do.

The control unit 120 controls the overall operation of the battery management system 100. For example, the control unit 120 may execute software for at least one of measurement of voltage, current, and temperature of the battery module 10, SOC calculation, SOH estimation, cell balancing, temperature management, and overcharge and overdischarge determination. Meanwhile, the technology for the control unit 120 to estimate the SOH based on the battery's voltage, current, temperature, accumulated usage time, etc. is already widely known, and detailed description thereof will be omitted.

The above-described control units 120 and 150 are hardware-wise, including application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), and field programmable gate arrays (FPGAs). ), microprocessors, and other electrical units for performing functions.

The control unit 120 may include a memory 121. The memory 121 may store various data, commands, and software required for the overall operation of the battery management system 100. The control unit 120 may refer to data and commands stored in the memory 121 or drive software to output a signal to control the operation of the charge/discharge circuit 20.

These memories 121 include flash memory 121 type, hard disk type, solid state disk type, SDD type (Silicon Disk Drive type), and multimedia card micro type ( multimedia card micro type), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM) memory) may include at least one type of storage medium.

Meanwhile, in FIG. 1, one of the components of the battery pack 1 or the battery management system 100 is shown as being connected to the other through at least one connection line (i.e., a communication line or a power line). . However, this is an example, and the actual implementation between the components of the battery management system 100 should not be understood as limited by the connection lines shown in FIG. 1.

Additionally, the battery management system 100 may be configured to have fewer components than those listed above or to further include additional components not listed above.

Hereinafter, the maximum voltage and maximum time that the battery module 10 can withstand without causing irreversible damage to the battery module 10 will be referred to as 'limit voltage' and 'limit time', respectively. For example, if the voltage of the battery module 10, which has a specific SOH value, remains above the 'limit voltage' for more than a 'limit time', irreversible damage may occur in the battery module 10. If the voltage of the battery module 10, which is the same SOH as the specific value above, is less than the 'limit voltage', it can be trusted that there is no irreversible damage to the battery module 10 even if the voltage continues for more than the 'limit time'. .

These limit voltages and limit times change depending on the SOH, and may be predetermined for each SOH through prior experiments. For example, since the overall range of SOH is from 0% to 100%, the limit voltage and limit time may be predetermined for each of a total of 100 SOH in increments of 1%. At this time, if the SOH of the battery module 10 estimated at a specific point in time is located between two predetermined adjacent SOHs, the control unit 120 uses an interpolation method to determine the SOH of the battery module 10 at the specific point in time. Limit voltage and limit time can also be estimated. Additionally, the reference voltage may be determined to be no greater than the limit voltage over the entire range of SOH.

FIGS. 2A and 2B are graphs showing changes in threshold voltage and threshold time according to SOH of the battery module 10. For convenience of explanation, the limit voltage and limit time when the SOH of the battery module 10 is 100% are 5V and 4 minutes, respectively, and the limit voltage and limit time when the SOH of the battery module 10 is 0% are Let's assume that they are 4.5V and 3.6 minutes, respectively.

In the graphs shown in FIGS. 2A and 2B, the limit voltage and limit time of the battery module 10 gradually decrease in the order of BOL (Beginning Of Life) → MOL (Middle Of Life) → EOL (End Of Life). You can confirm that it will be done. At this time, BOL and MOL may be divided by the first classification value S1, and MOL and EOL may be divided by the second classification value S2. The first classification value S1 and the second classification value S2 may be predetermined. there is.

In the following, it is assumed that the limit voltage and limit time when SOH reaches S1 are 4.8V and 3.84 minutes, respectively, and the limit voltage and limit time when SOH reaches S2 are 4.6V and 3.68 minutes.

Data representing the correlation between SOH, threshold voltage, and threshold time, such as those shown in FIGS. 2A and 2B, may be stored in advance in the memory 121.

Meanwhile, in FIGS. 2A and 2B, the slope that the threshold voltage and threshold time follow according to SOH is shown as a straight line, but this is only schematically shown to facilitate understanding and does not limit the scope of the present invention. That is, as SOH decreases, the threshold voltage and threshold time also decrease, and the slope during decrease may not be constant.

Let us assume that the reference voltage and reference time for determining whether the battery module 10 is overvoltage are fixed to 4.7V and 3.7 minutes, respectively. In this case, various problems may occur in terms of charging efficiency and safety for the battery module 10.

For example, even though the minimum limit voltage of the BOL is 4.8V, which is greater than 4.7V, as long as the voltage of the battery module 10 lasts between 4.8V and 4.7V for more than 3.7 minutes, the battery management system 100 controls the battery module 10 ) may be mistakenly judged to be currently in an overcharged state. Accordingly, charging may suddenly end even though the battery module 10 is not fully charged.

As another example, even though the maximum limit voltage of EOL is 4.6V, which is less than 4.7V, the battery management system 100 may incorrectly determine that the battery module 10 is not currently in an overvoltage state. Accordingly, even though the battery module 10 is already fully charged, the battery module 10 is continuously charged, which not only shortens the lifespan of the battery module 10 but also increases the risk of explosion.

The battery management system 100 and the battery pack 1 including the same according to embodiments of the present disclosure appropriately adjust the reference voltage for overvoltage determination based on the SOH of the battery module 10, see FIG. 2. Thus, the existing technical problems mentioned above can be overcome.

3 to 6 are referenced to explain how the battery management system 100 according to an embodiment of the present invention adjusts the reference voltage and reference time for overvoltage determination according to the SOH of the battery module 10. It is a drawing.

First, referring to FIG. 3, the control unit 120 may decrease the reference voltage as SOH decreases. Specifically, the control unit 120 may adjust the reference voltage so that the difference between the limit voltage of the battery and the reference voltage is constant throughout the SOH. For example, the difference Δ1 between the limit voltage and the reference voltage when SOH is S1 may be equal to the difference Δ2 between the limit voltage and the reference voltage when SOH is S2. In this case, the value of Δ1 may be previously stored in the memory 121. Although not shown together, the reference time may also be adjusted in a similar manner to the reference voltage.

Next, referring to FIG. 4, the control unit 120 is similar to the method described above with reference to FIG. 3 in that it decreases the reference voltage as SOH decreases. However, the method according to FIG. 4 is different from the method of FIG. 3 in that as SOH decreases, the difference between the limit voltage and the reference voltage increases. For example, the difference Δ3 between the limit voltage and the reference voltage when SOH is S1 is smaller than the difference Δ4 between the limit voltage and the reference voltage when SOH is S2. If the SOH of the battery module 10 is low, the durability of the battery module 10 is correspondingly reduced. As the SOH decreases, the difference between the limit voltage and the reference voltage increases, thereby strengthening the protection function for the battery module 10 that has relatively advanced deterioration. Although not shown together, the reference time may also be adjusted in a similar manner to the reference voltage.

Next, referring to FIG. 5, in contrast to the method of FIGS. 3 and 4 in which the reference voltage is gradually decreased according to SOH, the method is different in that the reference voltage is decreased in a stepwise manner.

Specifically, the control unit 120 divides the entire range of SOC into at least two or more sections, maintains the reference voltage constant during one section, and then performs the process of reducing the reference voltage at least once from the point of transition to another section. It can be done. For example, if the entire range of SOH is divided into three sections of BOL, MOL, and EOL, the reference voltage is maintained at V _S1 in BOL, and the reference voltage is maintained at V _S2 , which is smaller than V _S1 in MOL. Afterwards, at EOL, the reference voltage is lowered further and maintained at V _S3 .

At this time, V _S1 is preferably 4.8V or less, which is the minimum limit voltage of BOL, V _S2 is 4.6V, which is the minimum limit voltage of MOL, and V _S3 is preferably 4.5V or less, which is the minimum limit voltage of EOL.

According to the method of FIG. 5, the reference voltage is maintained constant while the SOH of the battery module 10 belongs to one of the plurality of sections classified as above, so the reference voltage changes as the SOH changes within the same section. It is possible to implement a function to prevent overcharging while reducing the amount of calculations required for frequent changes.

Meanwhile, in Figure 5, the explanation is centered on an implementation example in which the entire range of SOH is classified into three sections: BOL, MOL, and EOL. However, it should be noted in advance that the number of classified sections and each width can be freely changed as needed. Let it be known. Additionally, although not shown, the reference time may also be adjusted in a similar manner to the reference voltage.

Next, referring to FIG. 6, the control unit 120 divides the entire range of SOH into at least two or more sections, and when switching from one section to the next section, the control unit 120 can change the reference voltage adjustment method. That is, the control unit 120 can adjust the reference voltage by combining the methods of FIGS. 4 and 5 and the method of FIG. 6.

For example, as shown in FIG. 6, the control unit 120 can classify the entire range of SOH into a section before the limit voltage reaches a specific value of 4.6V and a section after it.

At this time, in the section before reaching 4.6V, similar to the method described above with reference to FIG. 4 or 5, the control unit 120 may gradually reduce the reference voltage to correspond to the slope of the decreasing limit voltage. Thereafter, from the section after reaching 4.6V, similar to the method described above with reference to FIG. 6, the control unit 120 may decrease the size of the reference voltage in a stepwise manner. Additionally, although not shown, the reference time may also be adjusted in a similar manner to the reference voltage.

7 and 8 are referenced to explain how the battery management system 100 according to another embodiment of the present invention adjusts the reference voltage and reference time for overvoltage determination according to the SOH of the battery module 10. It is a drawing.

First, Figure 7 illustrates the first lookup table L1. This first lookup table L1 is stored in advance in the memory 121. Specifically, the first lookup table L1 is configured to record a plurality of predetermined SOH sections and a plurality of reference voltages associated with each SOH section.

Let us assume that the entire range of SOH is divided into a total of 20 sections of 5% each. In this case, a plurality of reference voltages associated with each of a total of 20 classified sections may be recorded in the first lookup table L1. In other words, the number of reference voltages recorded in the first look-up table L1 is also 20, and can correspond one-to-one with the 20 sections.

Additionally, the first lookup table L1 may further record a plurality of reference times associated with each of the 20 sections. The number of reference times recorded in the first lookup table L1 is also 20, and may correspond one-to-one with the 20 sections.

When the SOH of the battery module 10 is estimated, the control unit 120 accesses the first lookup table L1 to determine the reference voltage associated with one SOH section to which the SOH of the battery module 10 belongs among a plurality of reference voltages. At least one of and reference time can be selected. For example, when the SOH of the battery module is estimated to be 98%, the control unit 120 may select 5.00V and 150 seconds from a plurality of reference voltages and reference times recorded in the first lookup table L1. . Thereafter, when the aging of the battery progresses and the SOH of the battery module 10 is estimated to be 9%, the control unit 120 selects among a plurality of reference voltages and reference times recorded in the first lookup table L1, 4.60V and 75 seconds are selectable. At this time, the point to note is that the lower the section to which the SOH of the battery belongs, the lower the reference voltage and reference time selected by the control unit 120.

The control unit 120 may determine the reference voltage based on the selected reference voltage. Together or separately from this, the control unit 120 may determine the reference time based on the selected reference time.

Next, FIG. 8 illustrates the second lookup table L2. This second lookup table (L2) may be previously stored in the memory 121 together with the first lookup table (L1). Specifically, the second lookup table L2 is configured to record a plurality of predetermined temperature sections and a plurality of weights associated with each temperature section. The number of temperature sections and the number of weights recorded in the second lookup table L2 are the same and may correspond one-to-one. The control unit 120 may select a weight associated with the temperature range to which the temperature of the battery belongs from among the plurality of weights.

The control unit 120 may determine the reference voltage based on the selected reference voltage and weight. Together or separately from this, the control unit 120 may determine the reference time based on the selected reference time and weight.

Let us assume that other conditions except the temperature of the battery module 10 are common and constant. As the temperature of the battery increases, the chemical reactions that occur in the battery become more active. As a result, even if the amount of charge charged in the battery module 10 is the same, as the temperature of the battery module 10 increases beyond the dropping point range (e.g., below 30°C, above 20°C), the voltage of the battery module 10 increases. increases. Conversely, as the temperature of the battery module 10 falls beyond the dropping point range (e.g., below 30°C, above 20°C), the voltage of the battery module 10 decreases. Accordingly, the reference voltage and reference time selected from the first lookup table L1 may be corrected in consideration of the change in voltage according to the temperature of the battery module 10.

For example, if the temperature at a specific point in time when SOH is estimated to be 98% is 47°C, the reference voltage, reference time, and weight selected by the control unit 120 will be 5.00V, 150 seconds, and 0.80, respectively. In this case, the control unit 120 may determine values equal to 5.00V and 150 seconds as the reference voltage and reference time, respectively. Alternatively, the control unit 120 may determine 4.00V, which is 5.00V multiplied by 0.80, as the reference voltage. Together or separately, the control unit 120 may determine 120 seconds, which is 150 seconds multiplied by 0.80, as the reference time.

Figure 9 is a flowchart showing a battery charging method according to an embodiment of the present invention. The battery charging method shown in FIG. 9 may be performed by the battery management system 100 described above.

Referring to FIG. 9, in step S910, the SOH of the battery module 10 is estimated. The SOH of the battery is estimated based on voltage, current, or temperature for a predetermined period of time measured by the sensing unit 110 before step S910 is started. Step S910 may be repeated every predetermined period.

In step S920, a reference voltage and a reference time for determining whether the battery module 10 is overvoltage are determined based on the SOH estimated through step S910.

Specifically, the control unit 120 may access the first lookup table and select at least one of a reference voltage and a reference time associated with an SOH section to which the SOH of the battery belongs from among a plurality of reference voltages. Next, the control unit 120 may determine the reference voltage based on the selected reference voltage. As an example, the same value as the selected reference voltage may be determined as the reference voltage. Simultaneously or separately, the control unit 120 may determine the reference time based on the selected reference time. For example, a value that is the same as the selected reference time or corrected by a predetermined value may be determined as the reference time. When step S920 is completed, step S930 is performed.

In step S930, it is determined whether the voltage of the battery module 10 remains above the reference voltage determined through step S930 for more than a reference time. If the result of the determination in step S930 is “YES,” step S940 is started.

In step S940, the battery management system 100 performs a predetermined overvoltage prevention operation. Specifically, the overvoltage prevention operation includes at least one of outputting a charging interruption signal and outputting an alarm signal.

When the control unit 120 outputs a charging stop signal, the charge/discharge circuit 20 stops charging the battery module 10 in response to the charge stop signal. Afterwards, the charge/discharge circuit 20 may wait until it receives a charge resumption signal from the control unit 120. When the control unit 120 outputs an alarm signal, the alarm signal is transmitted to the external device 2 connected to the battery pack 1. The external device 2 may output at least one of visual feedback, auditory feedback, and tactile feedback in response to the alarm signal.

The embodiments of the present invention described above are not only implemented through devices and methods, but may also be implemented through a program that realizes the function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded. The implementation can be easily implemented by an expert in the technical field to which the present invention belongs based on the description of the embodiments described above.

Although the present invention has been described above with limited examples and drawings, the present invention is not limited thereto, and the technical idea of the present invention and the description below will be understood by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalence of the patent claims.

In addition, the present invention described above is capable of various substitutions, modifications and changes without departing from the technical spirit of the present invention to those of ordinary skill in the technical field to which the present invention pertains. It is not limited by the drawings, and all or part of each embodiment can be selectively combined so that various modifications can be made.

1: Battery pack
10: Battery module
20: Charge/discharge circuit
21: Charging part
22: Discharge unit
100: Battery management system
110: Sensing unit
120: control unit
121: memory

Claims (13)

A sensing unit that measures the voltage of the battery module;
a memory storing a first lookup table in which a plurality of reference voltages and a plurality of reference times associated with each of a plurality of predetermined SOH sections are recorded; and
A control unit that determines whether the measured voltage is greater than the reference voltage for determining whether the battery module is overvoltage and continues for more than a reference time,
The control unit,
Estimate the SOH of the battery module,
Selecting a reference voltage associated with an SOH section to which the estimated SOH belongs from among the plurality of reference voltages,
Select a reference time associated with the SOH section to which the estimated SOH belongs from among the plurality of reference times,
Determine the reference voltage based on the selected reference voltage,
A battery management system, determining the reference time based on the selected reference time.
According to paragraph 1,
The control unit,
A battery management system that reduces at least one of the reference voltage and the reference time as the estimated SOH decreases. According to paragraph 1,
The sensing unit,
Further measure the temperature of the battery module,
The control unit,
A battery management system that determines at least one of the reference voltage and the reference time based on the estimated SOH and the measured temperature. According to paragraph 3,
The control unit,
A battery management system that reduces at least one of the reference voltage and the reference time as the measured temperature increases. delete delete A sensing unit that measures the voltage of the battery module;
a memory storing a first lookup table in which a plurality of reference voltages associated with each of a plurality of predetermined SOH sections are recorded, and a second lookup table in which a plurality of weights associated with each of a plurality of predetermined temperature sections are recorded; and
A control unit that determines whether the measured voltage is higher than the reference voltage for determining whether the battery module is overvoltage and continues for more than a reference time, wherein the control unit includes,
Estimate the SOH of the battery module,
Selecting a reference voltage associated with an SOH section to which the estimated SOH belongs from among the plurality of reference voltages,
Selecting a weight associated with a temperature section to which the measured temperature belongs from among the plurality of weights,
A battery management system that determines the reference voltage based on the selected reference voltage and the selected weight.
In clause 7,
In the first look-up table, a plurality of reference times associated with each of the plurality of SOH sections are further recorded,
The control unit,
Select a reference time associated with the SOH section to which the estimated SOH belongs from among the plurality of reference times,
A battery management system that determines the reference time based on the selected reference time and the selected weight.
According to paragraph 1,
The control unit,
A battery management system that performs a predetermined overvoltage prevention operation when the voltage of the battery module remains above the reference voltage for more than the reference time. battery module;
a charge/discharge circuit configured to selectively perform charging and discharging operations for the battery module; and
The battery management system according to any one of claims 1 to 4 and 7 to 9,
The battery management system is,
If the voltage of the battery module remains above the reference voltage for more than the reference time, performing a predetermined overvoltage prevention operation,
The charge/discharge circuit is,
A battery pack that stops the charging operation when the overvoltage prevention operation is performed.
estimating the SOH of the battery module;
By accessing a first lookup table in which a plurality of reference voltages and a plurality of reference times associated with each of a plurality of predetermined SOH sections are recorded, a reference voltage associated with the SOH section to which the estimated SOH belongs among the plurality of reference voltages and selecting a reference time associated with an SOH section to which the estimated SOH belongs from among the plurality of reference times;
Based on the selected reference voltage, determining a reference voltage for determining whether the battery module is overvoltage;
Based on the selected reference time, determining a reference time for determining whether the battery module is overvoltage; and
determining whether the voltage of the battery module remains above the reference voltage for more than the reference time;
Including, a battery module charging method.
estimating the SOH of the battery module;
Accessing a first lookup table in which a plurality of reference voltages associated with each of a plurality of predetermined SOH sections are recorded, and selecting a reference voltage associated with an SOH section to which the estimated SOH belongs from among the plurality of reference voltages;
Accessing a second lookup table in which a plurality of weights associated with each of a plurality of predetermined temperature sections are recorded, and selecting a weight associated with a temperature section to which the measured temperature belongs from among the plurality of weights;
determining a reference voltage for determining whether the battery module is overvoltage based on the selected reference voltage and the selected weight; and
determining whether the voltage of the battery module remains above the reference voltage for more than a reference time;
Including, a battery module charging method.
According to clause 12,
In the first look-up table, a plurality of reference times associated with each of the plurality of SOH sections are further recorded,
selecting a reference time associated with an SOH section to which the estimated SOH belongs from among the plurality of reference times; and
determining the reference time based on the selected reference time and the selected weight;
A battery module charging method further comprising:

Images