Patent Description:
The present invention relates to a battery management method and a battery system for providing the same, capable of extending cycle-life of a battery.

An electric vehicle (EV) is a vehicle that uses an electric battery and an electric motor without using petroleum fuel and an engine. Such electric vehicles include pure electric vehicles (EVs) that run only with batteries and electric motors, hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs).

The electric vehicle mainly uses a lithium ion battery as a battery, and a <NUM> V driving battery and a <NUM> V auxiliary battery may be installed. The electric vehicles that are recently mass-produced and distributed in the market may travel up to <NUM> on a single full charge (e.g., the Chevrolet Bolt EV), and this varies greatly depending on a vehicle type. Various modules/devices for user convenience in an electric vehicle consume power when driving, and thus may affect a mileage of the electric vehicle.

As a charging method for batteries, slow charging and rapid charging methods are selectively used. For such a charging time, it is known that slow charging takes <NUM> to <NUM> and rapid charging takes <NUM> to <NUM>, and with development of battery technology, slow charging or fast charging speed is being improved. A charger charges electrical energy by connecting a charging cable to a charging terminal of an electric vehicle, and typically supports a highspeed or low-speed charging type.

In the meanwhile, after a predetermined period of time elapses, for example, when a predetermined number of charge or discharge cycles is reached, a battery capable of charging and discharging rapidly deteriorates in performance and needs to be replaced. In particular, such a replacement period of the battery may be shortened or lengthened depending on a usage pattern of a user. For example, there are many research results showing that the cycle-life of the battery is shortened as a number of <NUM> % charging and discharging increases or as a number of times of charging by the rapid charging method rather than slow charging increases.

A ratio of a battery to the cost of an electric vehicle (EV) is about <NUM> %, which is very large. When the cycle-life of the battery is shortened as aging is accelerated as overcharge or over-discharge of the battery is repeated, a problem arises that a replacement cost of the battery increases. This may act as a burden when a user purchases an electric vehicle (EV), and may eventually become an obstacle to each country's policy of environmental protection by expanding a number of electric vehicles.

Accordingly, there is a need for a method capable of extending the cycle-life of the battery depending on an environment in which the electric vehicle is used, a user's tendency, and the like.

A Japanese patent application (<CIT>) provides a drive control device for a hybrid vehicle equipped with large auxiliaries to be able to meet the specific requirements of vehicles having large auxiliaries, such as prioritizing power supply to the loads of the large auxiliaries and prioritizing suppression of noise, heat generation, and exhaust gas generation. In <CIT>, the drive control device in a hybrid vehicle controls and switches different modes include a normal mode, a preparation mode, and an auxiliary use mode to meet the requirements of vehicles having large auxiliaries.

A European patent application (<CIT>) refers to a method and a system for improving cycle lifetimes for a lithium-ion battery pack, particularly for adapting to decreases in battery pack cell capacity as a function of age. In <CIT>, drive range modes are provided to the end user. Each of the modes may include its SOC window between a charge SOC and a discharge SOC. The second SOC window is less than the first SOC window.

A Japanese patent application (<CIT>) refers to a battery charging control system for a parallel hybrid electric vehicle, which allows the vehicle to run as much as possible using the motor rather than the engine during traffic jams due to high fuel consumption. Two control modes are provided, i.e. a normal SOC mode and a traffic congestion SOC mode. The upper limit SOC of the traffic congestion SOC mode is set higher than the upper limit SOC of the normal mode, while the lower limit SOC of the traffic congestion SOC mode is set lower than the lower limit SOC of the normal mode. Thus, it can run a considerable distance until the battery discharges to the lower limit SOC in the traffic congestion SOC mode.

A PCT application (<CIT>) refers to a method for improving the lifetime and the energy content of the battery pack assembly with an adjusted SOC window. The method at least includes determining an energy throughput or a current throughput of the battery pack assembly, determining a SOC window margin based on the said energy throughput or a current throughput.

A European patent application (<CIT>) provides a control apparatus for a hybrid vehicle, which is able to continue executing downhill control even if the controlled target section is updated when the hybrid vehicle is in the middle of traveling on a downhill section, which contributes to a reduction in fuel consumption. When the current location coincides with the downhill control start point Ds, SOCcntr-n is changed to SOCcntr-d.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

The present invention has been made in an effort to provide a battery management method and a battery system for provides the same, capable of reducing a usable battery capacity, and charging a battery with a slow charging method when an eco-friendly mode (ECO MODE) is on.

According to the present invention, it is possible to extend a cycle-life of a battery by reducing use of upper and lower limit SOCs of a usable battery capacity and a number of rapid charges, which accelerates aging of the battery.

According to the present invention, it is possible to reduce a number of charges by using a maximum available battery capacity, and to increase user satisfaction by enabling a user to select a normal mode, which provides convenience in using a battery with a short charging time, and an eco-friendly mode, which extends a cycle-life of the battery, depending on a situation.

In an embodiment, an electric vehicle indicates any vehicle that includes a battery and an electric motor for driving a wheel by using electricity charged in the battery. Such electric vehicles include electric vehicles (EVs) as well as plug-in hybrid electric vehicles (PHEVs). The electric vehicle may charge a battery with power supplied from a charging device that is electric vehicle supply equipment. The charging device may include a quick charger (or fast charger), a slow charging stand that supplies AC power in public places, and a home charger that is simply installed at home or at work to supply AC power.

Hereinafter, embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings. In the present specification, the same or similar components will be denoted by the same or similar reference numerals, and a repeated description thereof will be omitted. Terms "module" and/or "unit" for components used in the following description are used only in order to easily describe the specification. Therefore, these terms do not have meanings or roles that distinguish them from each other in and of themselves. In describing embodiments of the present specification, when it is determined that a detailed description of the well-known art associated with the present invention may obscure the gist of the present invention, it will be omitted. The accompanying drawings are provided only in order to allow embodiments disclosed in the present specification to be easily understood and are not to be interpreted as limiting the spirit disclosed in the present specification, and it is to be understood that the present invention includes all modifications, equivalents, and substitutions without departing from the scope of the appended claims.

Terms including ordinal numbers (e.g., natural numbers) such as first, second, and the like will be used only to describe various components, and are not to be interpreted as limiting these components. The terms are only used to differentiate one component from other components.

It is to be understood that when one component is referred to as being "connected" or "coupled" to another component, it may be connected or coupled directly to the other component or be connected or coupled to the other component with a further component intervening therebetween. On the other hand, it is to be understood that when one component is referred to as being "connected or coupled directly" to another component, it may be connected to or coupled to the other component without another component intervening therebetween.

It will be further understood that terms "comprises/includes" or "have" used in the present specification specify the presence of stated features, numerals, steps, operations, components, parts, or a combination thereof, but do not preclude the presence or addition of one or more other features, numerals, steps, operations, components, parts, or a combination thereof.

<FIG> illustrates a battery system according to an embodiment.

Referring to <FIG>, the battery system <NUM> includes a battery <NUM>, a relay <NUM>, a current sensor <NUM>, and a battery management system (BMS) <NUM>.

The battery <NUM> includes a plurality of battery cells Cell1 to Celln that are electrically connected. In some embodiments, the battery cells may be rechargeable batteries. A predetermined number of battery cells may be connected in series to constitute a battery module, and a predetermined number of battery modules may be connected in series and parallel to constitute the battery <NUM> to supply desired power. Each of the battery cells Cell1 to Celln is electrically connected to the BMS <NUM> through wires.

In <FIG>, the battery <NUM> includes the plurality of battery cells Cell1 to Celln connected in series, and is connected between two output terminals OUT1 and OUT2 of the battery system <NUM>. The relay <NUM> is connected between a positive electrode of the battery <NUM> and the output terminal OUT1, and the current sensor <NUM> is connected between a negative electrode of the battery <NUM> and the output terminal OUT2. The constituent elements illustrated in <FIG> and a connection relationship between the constituent elements are examples, and the present invention is not limited thereto.

The relay <NUM> controls electrical connection between the battery system <NUM> and an external device. When the relay <NUM> is turned on, the battery system <NUM> and the external device are electrically connected to perform charging or discharging, and when the relay <NUM> is turned off, the battery system <NUM> and the external device are electrically separated. In this case, the external device may serve as a charger in a charging mode in which the battery <NUM> is charged by supplying power, or a load in a discharge mode in which power stored in the battery <NUM> is discharged.

The current sensor <NUM> is connected in series to a current path between the battery <NUM> and the external device. The current sensor <NUM> may measure a current flowing through the battery <NUM>, i.e., a charging current and a discharging current, and may transmit a measurement result to the BMS <NUM>.

The BMS <NUM> may collect and analyze various information related to the battery cells Cell1 to Celln to control charging and discharging of the battery cells, cell balancing, a protection operation, and the like, and may control an operation of the relay <NUM>. For example, the BMS <NUM> may control charging of the battery <NUM> in a normal mode (NORMAL MODE) or an eco-friendly mode (ECO MODE) depending on user selection.

In the normal mode (NORMAL MODE), the battery <NUM> uses a maximum usable battery capacity (hereinafter, a first battery capacity) within a designed range, and uses a charging method selected by a user among a slow charging method or a rapid charging method to charge the battery <NUM>. For example, the normal mode (NORMAL MODE) is a method of using and managing the battery <NUM> in an initially designed state.

In the eco-friendly mode (ECO MODE), the battery <NUM> uses a narrower battery capacity (hereinafter, second battery capacity) than the maximum usable battery capacity in a designed range, and charges the battery <NUM> by a slow charging method. For example, the eco-friendly mode (ECO MODE) is a battery management method for extending the cycle-life of the battery <NUM>, and may be set by user selection. That is, the eco-friendly mode (ECO MODE) is a battery management method that slows down an aging rate of the battery <NUM> by limiting excessive use of the battery capacity and the rapid charging method.

A state of charge (SOC) is an amount of energy that is currently stored in the battery <NUM>, and a unit thereof is percent (%). When the battery <NUM> is fully charged, the state of charge SOC is <NUM> %. When the battery <NUM> is completely discharged, the state of charge (SOC) is <NUM> %. When the fully charged battery <NUM> starts to be discharged, the state of charge (SOC) decreases to <NUM> %, <NUM> %, <NUM> %, etc. as time elapses. In the meantime, the state of charge (SOC) cannot be directly measured, and the BMS <NUM> may estimate the state of charge (SOC) by an indirect method such as a conventionally known current integration method or a voltage measurement method. The BMS <NUM> may estimate the state of charge (SOC) in a predetermined period or in real time.

The battery capacity is a total amount of energy that the battery <NUM> can store, and the unit is ampere-hours (Ah) and represents how long a constant current can flow. For example, when a current of <NUM> A flows for <NUM> hour, the battery capacity is <NUM> AH, and when it flows for <NUM> hours, the battery capacity is <NUM> AH.

According to an embodiment, the first battery capacity may include a battery capacity having a range between a first lower limit SOC and a first upper limit SOC provided in a design and production process of the battery <NUM>. For example, the first battery capacity may include a battery capacity defined as <NUM> % to <NUM> %, or substantially in a range of <NUM> % to <NUM> % in consideration of a design margin, resistance, calculation error, and the like. The second battery capacity may include a battery capacity in a narrower region than the first battery capacity in order to slow the aging rate of the battery <NUM>. Specifically, the second battery capacity may include a battery capacity having a range between a second lower limit SOC that is a predetermined magnitude that is greater than the first lower limit SOC and a second upper limit SOC that is a predetermined magnitude that is smaller than the first upper limit SOC. For example, the second battery capacity may include a battery capacity defined as a range between <NUM> % and <NUM> %.

In the normal mode (NORMAL MODE), the BMS <NUM> enters a charging mode for supplying power to the battery <NUM> when the state of charge (SOC) reaches the first lower limit SOC (e.g., <NUM> %). When a real-time state of charge (SOC) reaches the first upper limit SOC (e.g., <NUM> %) by supplying power to battery <NUM>, the BMS <NUM> may end the charging mode. In addition, in the eco-friendly mode (ECO MODE), the BMS <NUM> enters a charging mode for supplying power to the battery <NUM> when the state of charge (SOC) reaches the second lower limit SOC (e.g., <NUM> %). When a real-time state of charge (SOC) reaches the second upper limit SOC (e.g., <NUM> %) by supplying power to battery <NUM>, the BMS <NUM> may end the charging mode.

Slow charging and rapid charging are battery charging methods that are divided depending on the charging speed. The slow charging is a slow charging method for completing the charging of the battery <NUM> after exceeding a predetermined reference time. The rapid charging is a fast charging method for completing the charging of the battery <NUM> within a predetermined reference time.

In the meantime, when using the battery at a maximum capacity, e.g., when the first lower limit SOC (e.g., <NUM> %) and the first upper limit SOC (e.g., <NUM> %) are repeatedly used, or when using an extended battery capacity (<NUM> % to <NUM> % or <NUM> % to <NUM> %), aging of the battery <NUM> may be accelerated. In addition, when the battery <NUM> is charged by the rapid charging method, the aging of the battery <NUM> may be accelerated compared to when the battery <NUM> is charged by the slow charging method.

As the battery <NUM> ages with use after being manufactured, a total amount of storable energy (battery capacity) also decreases. A state of health (SOH) is a performance index that is obtained by comparing an ideal battery state with a current battery state. For example, although the battery <NUM> initially had a battery capacity of <NUM> mAh, the battery capacity may decrease to <NUM> mAh after use for a predetermined period of time. Then, the battery state of health (SOH) becomes <NUM> %.

For reference, when the battery state of health (SOH) is <NUM> %, states of charge (SOC) at the time of full charge and full discharge of the battery <NUM> are <NUM> % and <NUM> %, respectively. In addition, when the battery state of health (SOH) is <NUM> %, the states of charge (SOC) at the time of full charge and full discharge of the battery <NUM> are <NUM> % and <NUM> %, respectively. That is, the state of charge (SOC) is <NUM> % when the energy that can be filled in the battery <NUM> is fully filled, and is <NUM> % when the energy is exhausted, regardless of the state of health (SOH) of the battery. However, the battery <NUM> with a battery state of health (SOH) of <NUM> % can supply a total of <NUM> mAh of energy after being fully charged, whereas the battery <NUM> with a battery state of health (SOH) of <NUM> % can only supply a total of <NUM> mAh energy after being fully charged.

That is, the battery capacity decreases in response to the battery state of health (SOH). For example, a time when the battery state of health (SOH) is decreased to a predetermined reference value, e.g., <NUM> %, may be regarded as a battery replacement time. When the battery state of health (SOH) falls below <NUM> %, the battery capacity is rapidly deteriorated and the battery <NUM> cannot perform its original role.

<FIG> illustrate views for describing a normal mode according to an embodiment, and <FIG> illustrate views for describing an eco-friendly mode according to an embodiment.

According to an embodiment, a first key Key_1 for executing the eco-friendly mode (ECO MODE) may be provided on a user interface (not illustrated). When a user selects (ON) or non-selects (OFF), the first key Key_1 that performs the eco-friendly mode (ECO MODE), the BMS <NUM> may control the charging of the battery <NUM> in the eco-friendly mode (ECO MODE) depending on user selection (ON) or the normal mode (NORMAL MODE) depending on non-selection (OFF). For example, the BMS <NUM> may receive a first key-on signal for selecting the first key Key_1 or a first key-off signal for not selecting the first key Key_1 from an electronic control unit (ECU).

According to another embodiment, the first key Key_1 for executing the eco-friendly mode (ECO MODE) and a second key Key_2 for executing the normal mode (NORMAL MODE), which can be manipulated by the user, may be provided in a user interface. When the user selects (ON) of the first key Key_1 for executing the eco-friendly mode (ECO MODE), the BMS <NUM> may control the charging of the battery <NUM> in the eco-friendly mode (ECO MODE). When the user selects (ON) of the second key Key_2 for executing the normal mode (NORMAL MODE), the BMS <NUM> may control the charging of the battery <NUM> in the normal mode (NORMAL MODE). For example, the BMS <NUM> may receive the first key-on signal for selecting the first key Key_1 or a second key-on signal for selecting the second key Key_2 of the normal mode (NORMAL MODE) from the electronic control unit (ECU).

Referring to <FIG>, in an ON state of the normal mode (NORMAL MODE), the first battery capacity is set to a usable battery capacity (hereinafter, the available battery capacity), and rapid charging is enabled. Accordingly, the BMS <NUM> may control the charging of the battery <NUM> in a first battery capacity range by the fast charging or slow charging method depending on the user selection.

Referring to <FIG>, when the battery <NUM> is used and managed in the normal mode (NORMAL MODE), an end of life (EOL) of the battery <NUM> may be determined as a time when the available battery capacity reaches a predetermined reference value (<NUM> %) compared to an initial state (<NUM> %). That is, when the battery state of health (SOH) reaches <NUM> %, the battery <NUM> should be discarded. In this case, the end of life (EOL) may be determined depending on a number of charge and discharge cycles. For example, a lithium-ion battery is determined to have reached the end of life (EOL) when <NUM> to <NUM> charge and discharge cycles have elapsed.

Referring to <FIG>, in the ON state of the eco-friendly mode (ECO MODE), the second battery capacity is set to an available battery capacity, and the fast charging method is disabled. Accordingly, the BMS <NUM> may control the charging of the battery <NUM> in a second battery capacity range by the slow charging method. In this case, the second battery capacity may be set to a battery capacity in a range that is smaller than the first battery capacity.

Referring to <FIG>, when the battery <NUM> is used and managed in the eco-friendly mode (ECO MODE), an end of life (EOL+α) of the battery <NUM> may be extended for a predetermined period of time α than when the battery <NUM> is used and managed in the normal mode (NORMAL MODE).

<FIG> illustrates a flowchart describing a method of extending cycle-life of a battery by charging the battery in a normal mode or an eco-friendly mode depending on user selection according to an embodiment.

Hereinafter, a battery management method and a battery system providing the method will be described with reference to <FIG>.

Referring to <FIG>, the BMS <NUM> determines whether the eco-friendly mode (ECO MODE) is in an on state by user selection (S10).

According to an embodiment, a first key Key_1 for executing the eco-friendly mode (ECO MODE) may be provided on a user interface (not illustrated). When a user selects the first key Key_1, the BMS <NUM> may determine the eco-friendly mode (ECO MODE), while when the user does not select the first key Key_1, the BMS <NUM> may determine the normal mode (NORMAL MODE). That is, when the user does not take any action, the BMS <NUM> may determine the normal mode (NORMAL MODE). For example, the BMS <NUM> may receive a first key-on signal for indicating selection of the first key Key_1 or a first key-off signal for indicating non-selection of the first key Key_1 from an electronic control unit (ECU).

According to another embodiment, the first key Key_1 for executing the eco-friendly mode (ECO MODE) and a second key Key_2 for executing the normal mode (NORMAL MODE) may be provided in a user interface. When the user selects the first key Key_1, the BMS <NUM> may determine the eco-friendly mode (ECO MODE), while when the user does not select the second key Key_2, the BMS <NUM> may determine the normal mode (NORMAL MODE). For example, the BMS <NUM> may receive the first key-on signal for selecting the first key Key_1 or a second key-on signal for selecting the second key Key_2 of the normal mode (NORMAL MODE) from the electronic control unit (ECU).

Next, when the eco-friendly mode (ECO MODE) is in an off state (S10, No), the BMS <NUM> controls the charging of the battery <NUM> in the normal mode (NORMAL MODE) (S20).

In step S20, first, the BMS <NUM> diagnoses whether a current state of charge (SOC) reaches a first lower limit SOC of the first battery capacity (S21).

The normal mode (NORMAL MODE) is a method of managing the battery <NUM> as designed. The normal mode (NORMAL MODE) uses the first battery capacity, which is a maximum battery capacity that is usable in the designed range. In this case, the first battery capacity may be a battery capacity having a range between a first lower limit SOC and a first upper limit SOC provided in a design and production process of the battery <NUM>. Assuming an ideal state, the first battery capacity may include a battery capacity defined in a range between <NUM> % and <NUM> %. The BMS <NUM> may calculate the current state of charge (SOC) by estimating the state of charge (SOC) in a predetermined period or in real time.

In step S20, when the state of charge SOC reaches the first lower limit SOC (S21, Yes), the BMS <NUM> enters a charging mode for supplying power to the battery <NUM> (S22).

The BMS <NUM> may control the charging of the battery <NUM> in a first battery capacity range by the fast charging or slow charging method depending on the user selection. For example, when the user selects the rapid charging, the BMS <NUM> may control power to be supplied to the battery <NUM> through rapid charging.

According to an embodiment, when there is no user selection of the charging method, the BMS <NUM> may request the user to select the charging method through the electronic control unit (ECU). The electronic control unit (ECU) may control a message requesting selection of one of the fast charging and the slow charging method to be displayed on a user interface.

In step S20, the BMS <NUM> diagnoses whether a current state of charge (SOC) reaches a first upper limit SOC of the first battery capacity (S23).

In the charging mode, the battery <NUM> receives power from an external device, and the state of charge (SOC) increases as time elapses. For example, in the case where charging is started when the state of charge (SOC) is <NUM> %, the state of charge (SOC) may gradually increase to <NUM> %, <NUM> %, or <NUM> % as time elapses.

Next, when the eco-friendly mode (ECO MODE) is in an on state (S10, Yes), the BMS <NUM> controls the charging of the battery <NUM> in the eco-friendly mode (ECO MODE) (S30).

In step S30, first, the BMS <NUM> diagnoses whether the state of charge (SOC) reaches a second lower limit SOC of the second battery capacity (S31).

The eco-friendly mode (ECO MODE) is a battery management method for extending the cycle-life of the battery <NUM>, and may be set by user selection. In the eco-friendly mode (ECO MODE), the second battery capacity, which is a battery capacity in a narrower region than that of the first battery capacity, is used. In this case, the second battery capacity may include a battery capacity having a range between a second lower limit SOC that is a predetermined magnitude that is greater than the first lower limit SOC and a second upper limit SOC that is a predetermined magnitude that is smaller than the first upper limit SOC. For example, the second battery capacity may include a battery capacity defined as a range between <NUM> % and <NUM> %.

Referring to <FIG>, the first lower limit SOC of the first battery capacity is smaller than the second lower limit SOC of the second battery capacity, and the first upper limit SOC is greater than the second upper limit SOC of the second battery capacity.

In step S30, when the state of charge SOC reaches the second lower limit SOC (S31, Yes), the BMS <NUM> enters a charging mode for supplying power to the battery <NUM> (S32).

Since the rapid charging method is disabled, the BMS <NUM> may control the charging of the battery <NUM> in the second battery capacity range by the slow charging method. When the state of charge (SOC) reaches the second lower limit SOC, e.g., <NUM> %, the BMS <NUM> may control the battery <NUM> to be charged without further discharging.

In step S30, the BMS <NUM> diagnoses whether the state of charge (SOC) reaches the second upper limit SOC of the second battery capacity (S33).

Next, when the current state of charge (SOC) reaches the first upper limit SOC or the second upper limit SOC (S23, Yes), the BMS <NUM> may end the charging mode S40.

When the battery <NUM> is fully charged up to the first upper limit SOC, the BMS <NUM> may end charging of the battery <NUM>(S40). For example, the BMS <NUM> may end the charging of the battery <NUM> when the state of charge (SOC) reaches <NUM> %.

When the battery <NUM> is fully charged up to the second upper limit SOC, the BMS <NUM> may end charging of the battery <NUM>(S40). For example, in the case where charging is started when the state of charge (SOC) is <NUM> %, the state of charge (SOC) may gradually increase to <NUM> % or <NUM> % as time elapses. When the state of charge (SOC) reaches the second upper limit SOC, e.g., <NUM>%, the BMS <NUM> may end the charging mode such that the battery <NUM> is no longer charged.

Claim 1:
A battery system, comprising:
a battery; and
a battery management system, BMS, configured to control charging of the battery depending on a normal mode where the battery is charged with a first battery capacity between a first lower limit state of charge, SOC, and a first upper limit SOC or an eco-friendly mode, ECO MODE, where the battery is charged with a second battery capacity between a second lower limit SOC and a second upper limit SOC,
wherein the first lower limit SOC is smaller than the second lower limit SOC, and
the first upper limit SOC is greater than the second upper limit SOC,
wherein the BMS is configured to, in an on state of the normal mode, calculate a current SOC by estimating a SOC of the battery every predetermined period, and start charging of the battery when the current SOC reaches the first lower limit SOC and end the charging of the battery when the current SOC reaches the first upper limit SOC,
wherein the BMS is configured to, in an on state of the normal mode, control charging of the battery by using a rapid charging method of charging the battery for completing the charging of the battery from when the current SOC reaches the first lower limit SOC until when the current SOC reaches the first upper limit SOC within a predetermined reference time or performing a slow charging method of charging the battery for completing the charging of the battery from when the current SOC reaches the first lower limit SOC until when the current SOC reaches the first upper limit SOC after exceeding the predetermined reference time,
wherein the BMS is configured to, in an on state of the normal mode, control the charging of the battery by the rapid charging method or the slow charging method depending on user selection.