Patent Description:
In recent years, research and development for secondary batteries have been actively conducted. Here, the secondary battery is a battery capable of recharging and discharging, and in its meaning, includes all of the existing Ni/Cd battery, the Ni/MH battery, and the like and a recent lithium-ion battery. Among secondary batteries, lithium-ion batteries have the advantage of having much higher energy density than the existing Ni/Cd batteries and Ni/MH batteries. In addition, lithium-ion batteries may be manufactured in a small size and light weight, and accordingly, may be used as power sources for mobile devices. In addition, the lithium-ion batteries have expanded their range of use to power sources for electric vehicles, making the batteries attract attention as a next-generation energy storage medium.

In addition, the secondary battery is generally used as a battery pack including a battery module in which a plurality of battery cells are connected in series and/or in parallel. The state and operation of the battery pack are managed and controlled by a battery management system.

The battery pack uses a pre-charge circuit that includes a pre-charge relay and a pre-charge resistor to protect a positive relay. However, in the parallel-connection battery pack structure, the pre-charge circuits are redundantly used, resulting in an increase in manufacturing cost and unnecessarily complex control logic to be applied.

On the other hand, in the parallel-connection battery pack structure in the related art, if a relay control used for one battery and a diagnostic logic are used, interference may occur between packs connected in parallel, which may lead to misdiagnosis.

Further background art is disclosed in the following documents.

<CIT> discloses a battery management system, which includes a first battery pack which supplies power to a load, a first ground unit which is connected between a first relay which is connected to the first battery pack to connect and disconnect power supply of the battery pack and the first battery pack, a second battery pack which supplies power to a load, a second ground unit which is connected between a second relay which is connected to the second battery pack to connect and disconnect power supply of the battery pack and the second battery pack and a voltage measuring unit which measures voltages of both ends of the first relay and voltages of both ends of the second relay.

<CIT> discloses a battery management system (BMS) and a method of controlling the BMS, which are capable of increasing reliability of determination of a defect of a relay by considering not only a voltage of a battery and a voltage of an inverter but also a current between the battery and the inverter and information regarding an operational state of the relay.

The present invention provides a battery system according to claim <NUM>, and a battery relay diagnostic method for diagnosing a battery system according to claim <NUM>.

The present disclosure has been made to solve the above-mentioned problems, and describes a battery relay diagnostic device and method capable of reducing cost and simplifying a control logic by minimizing a configuration of a pre-charge circuit of battery packs connected in parallel, and preventing misdiagnosis by performing diagnosis according to a state of each relay in consideration of the effect of interference from other battery packs connected in parallel.

There is described in the following, in accordance with a background example that is helpful for understanding the invention, a battery relay diagnostic device for diagnosing a battery system including a plurality of battery packs connected in parallel, and a charge and discharge controller connected between the plurality of battery packs and a load part and controlling charge and discharge of the plurality of battery packs, the battery pack includes a battery cell module including a plurality of battery cells, and a switching unit including a first switch provided between a positive ((+)) terminal of the battery cell module and a load part and a second switch provided a negative ((-)) terminal of the battery cell module and the load part, and the battery relay diagnostic device includes a switching controller controlling a current applied to the battery cell module by controlling on/off of the switching unit and a diagnostic unit performing diagnosis on the first switch and the second switch based on an on/off state of the first switch and the second switch.

There is also described herein, in accordance with a background example that is helpful for understanding the invention, a battery relay diagnostic method for a battery system including a plurality of battery packs, the battery system including a charge and discharge controller connected between the battery packs connected in parallel and a load part and controlling charge and discharge of battery cell modules included in the battery packs, and the battery packs including the battery cell module including a plurality of battery cells and a switching unit including a first switch provided between a positive ((+)) terminal of the battery cell module and the load part and a second switch provided between a negative ((-)) terminal of the battery cell module and the load part, and the method includes performing diagnosis on the first switch and the second switch based on an on/off state of the first switch and the second switch.

According to the battery relay diagnostic device and method set out above, it is possible to reduce cost and simplify control logic by minimizing the configuration of the pre-charge circuit of battery packs connected in parallel, and to prevent misdiagnosis by performing diagnosis according to a state of each relay in consideration of the effect of interference from other battery packs connected in parallel.

Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the present disclosure, the same reference numerals are used for the same elements in the drawings, and duplicate descriptions for the same elements are omitted.

In various embodiments of the present disclosure disclosed herein, specific structural or functional descriptions are merely exemplary for the purpose of describing embodiments of the present disclosure, and various embodiments of the present disclosure may be implemented in various forms and should not be construed as being limited to the embodiments described herein.

As used in various embodiments, the terms such as "first", "second", "the first", or "the second" may modify various components, regardless of order and/or importance, but do not limit the components. For example, without departing from the scope of the present disclosure, a first element could be termed a second element, and similarly, in reverse, a second element could be termed a first element.

The terms and phrases as used herein are merely provided to describe specific embodiments, and may not be intended to limit the scope of other embodiments. A singular form is intended to include a plural form, unless the context clearly indicates otherwise.

All terms, including technical or scientific terms, as used here, may have the same meaning as commonly understood by a person skilled in the art to which the present disclosure belongs. Terms such as those defined in commonly-used dictionaries should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined here. In some cases, even terms defined here cannot be interpreted to exclude embodiments of the present disclosure.

<FIG> is a block diagram illustrating a configuration of a single battery control system.

Referring to <FIG>, a battery control system including a battery pack <NUM> according to an embodiment of the present disclosure and an upper-level controller <NUM> included in an upper-level system is schematically illustrated.

As illustrated in <FIG>, the battery pack <NUM> may be made of one or more battery cells, and may include a rechargeable battery module <NUM>, a switching unit <NUM> connected to a (+) terminal or a (-) terminal of the battery module <NUM> in series to control a charge and discharge current flow of the battery module <NUM>, and a battery management system <NUM> for controlling and managing by monitoring voltage, current, temperature, or the like of the battery pack <NUM> to prevent over-charging, over-discharging, or the like.

Here, the switching unit <NUM> is a switching element for controlling a current flow for charging or discharging of the battery module <NUM>, and generally uses a relay, but may include a semiconductor switching element. For example, at least one relay or one metal-oxide-semiconductor field-effect transistor (MOSFET) may be used.

In addition, the battery management system (BMS) <NUM> may monitor the voltage, current, temperature, or the like, of the battery pack <NUM> in order to ensure the safety of the battery, and to this end, may directly receive the values or use a sensor <NUM> to measure the current, voltage, temperature, or the like, of the battery pack. The BMS <NUM> may be an interface for receiving values obtained by measuring the above-mentioned various parameters, and may include a plurality of terminals, a circuit connected to the terminals to process input values, or the like.

In addition, the BMS <NUM> may control ON/OFF of the switching element <NUM>, for example, a relay or a MOSFET, and may be connected to the battery module <NUM> to monitor the status of the battery module <NUM>.

The upper-level controller <NUM> may transmit a control signal for the battery module to the BMS <NUM>. Accordingly, the operation of the BMS <NUM> may be controlled based on the signal applied from the upper-level controller. The battery cell described in the present disclosure may be included in a battery pack used in an energy storage system (ESS), a vehicle, or the like. However, it is not limited to the above-mentioned uses.

The configuration of the battery pack <NUM> and the configuration of the BMS <NUM> are known, and thus a more detailed description will be omitted.

<FIG> is a block diagram illustrating a configuration of a battery system including a battery relay diagnostic device according to an embodiment of the present disclosure.

Referring to <FIG>, a battery system <NUM> according to an embodiment of the present disclosure includes a plurality of battery packs <NUM>, a charge and discharge controller <NUM>, and a battery relay diagnostic device <NUM>.

The plurality of battery packs <NUM> are connected in parallel, and each is connected to the charge and discharge controller <NUM>. Only one charge and discharge controller <NUM> may be provided regardless of the number of battery packs <NUM> connected in parallel. In this case, each of the battery packs <NUM> may include a battery cell module <NUM> and a switching unit <NUM>.

The battery cell module <NUM> includes a plurality of battery cells connected in series or in parallel.

The switching unit <NUM> includes a first switch provided between a (+) terminal of the battery cell module <NUM> and a load part and a second switch provided between a (-) terminal of the battery cell module and the load part.

The charge and discharge controller <NUM> may control charge and discharge of a plurality of battery packs <NUM> connected in parallel. In this case, the charge and discharge controller <NUM> may include a charge/discharge switching unit <NUM> and a pre-charge unit <NUM>. In addition, the charge and discharge controller <NUM> may include only one pre-charge circuit.

The charge/discharge switching unit <NUM> may include a positive relay connected to the (+) side of the battery pack <NUM> connected to others in parallel and a negative relay connected to the (-) side of the battery pack <NUM> connected to others in parallel. The charge/discharge switching unit <NUM> may control the positive relay and the negative relay to control a current flow applied between the battery pack <NUM> and a load part.

The pre-charge unit <NUM> may include a pre-charge circuit in which a pre-charge resistor and a pre-charge relay are connected in series, and may be connected in parallel to the positive relay of the charge/discharge switching unit <NUM>. The pre-charge unit <NUM> may protect the positive relay by controlling a speed during initial charging of the battery pack <NUM>.

The battery relay diagnostic device <NUM> may diagnose the battery pack <NUM> included in the battery pack <NUM> about whether it operates normally. In this case, the battery relay diagnostic device <NUM> may include a switching controller <NUM>, a diagnostic unit <NUM>, and an alarm unit <NUM>.

The switching controller <NUM> may control the current applied to the battery cell module <NUM> by controlling on/off of the switching unit <NUM> and the charge/discharge switching unit <NUM> of the battery pack <NUM>. That is, according to the present disclosure, by diagnosing the switching unit <NUM> of the battery pack <NUM>, the switching controller <NUM> may control on/off of the first switch provided between the (+) terminal of the battery cell module <NUM> and the load part and the second switch provided between the (-) terminal of the battery cell module and the load part, thereby controlling the current applied to the battery cell module <NUM>, and the diagnostic unit <NUM> may diagnose the first switch and the second switch about whether they operate normally.

The diagnostic unit <NUM> performs diagnosis on the first switch and the second switch based on the on/off states of the first switch and the second switch. The diagnostic unit <NUM> performs diagnosis on the first switch and the second switch in an order determined in consideration of interference between the plurality of battery packs <NUM> connected in parallel, as will be described later.

Specifically, the diagnostic unit <NUM> may perform diagnosis by simultaneously measuring a voltage across the first switch for the plurality of battery packs <NUM> when both the first switch and the second switch are in an off state, and may perform diagnosis by sequentially measuring a voltage across a terminal of the first switch close to a (+) side of the battery cell module <NUM> and a terminal of the second switch close to the load part for each of the plurality of battery packs <NUM>.

Furthermore, the diagnostic unit <NUM> may perform diagnosis by simultaneously measuring the voltage across the terminal of the first switch close to the (+) side of the battery cell module <NUM> and the terminal of the second switch close to the load part for the plurality of battery packs <NUM> when the first switch is in the off state and the second switch is in the on state. In addition, the diagnostic unit <NUM> may perform diagnosis by sequentially measuring the voltage across the first switch for each of the plurality of battery packs when both the first switch and the second switch are in the on state.

The alarm unit <NUM> may generate a warning notification when it is determined that an abnormality occurs in at least one of the first switch and the second switch of the plurality of battery packs <NUM> by the diagnostic unit <NUM>.

As described above, with the battery relay diagnostic device of the present disclosure, it is possible to reduce cost and simplify control logic by minimizing the configuration of the pre-charge circuit of battery packs connected in parallel, and to prevent misdiagnosis by performing diagnosis depending on a state of each relay in consideration of the effect of interference from other battery packs connected in parallel.

<FIG> is a diagram illustrating a relay configuration of a battery system in the related art, and <FIG> is a diagram illustrating a relay control method for the battery system in the related art.

As illustrated in <FIG>, the battery system in the related art generally includes a single pack structure and eliminates the pre-charge circuit to reduce costs. Therefore, as illustrated in <FIG>, the battery management system (BMS) performs diagnosis on relays by measuring the voltages at each of points A, B, and C after waking up, regardless of the on/off state of each relay.

However, when a plurality of single packs illustrated in <FIG> and <FIG> are connected in parallel, it is likely that misdiagnosis occurs since relays interfere with each other. Therefore, a new relay control and diagnosis method is required in battery packs having a parallel structure.

<FIG> is a diagram illustrating a relay configuration of a battery system according to an embodiment of the present disclosure and an interference when relays are off, and <FIG> is a diagram illustrating a relay control method for the battery system when the first switch and the second switch are off.

Referring to <FIG> and <FIG>, in the battery system according to an embodiment of the present disclosure, interference may occur between battery packs connected in parallel, and diagnosis is performed by classifying each battery pack according to the on/off state of the relay.

Specifically, referring to <FIG>, when both the first switch and the second switch of the battery pack are in the off state, the battery pack voltage is applied to points A of a first pack and a second pack of <FIG> and a B voltage is OV, which does not affect both battery packs, and thus the measurement of the B voltage may be simultaneously performed for a plurality of battery packs.

On the other hand, in the case of measuring a C voltage while both the first switch and the second switch of the battery pack are in the off state, diagnosis is performed by connecting points A and C, and in this case, as indicated by an arrow (solid line) in <FIG>, interference between the first pack and the second pack may occur. Therefore, as illustrated in <FIG>, the C voltage has to be sequentially measured for each battery pack.

<FIG> is a diagram illustrating a relay configuration of a battery system according to an embodiment of the present disclosure and an interference when relays are on, and <FIG> is a diagram illustrating a relay control method for the battery system when the first switch and the second switch are on.

Referring to <FIG>, when the first switch of the battery pack is in the off state and the second switch is in the on state, a C voltage and a D voltage of a first pack and a second pack of <FIG> are ground voltages and OV is applied, which does not affect the battery packs, and thus the measurement of the C voltage may be simultaneously performed for a plurality of battery packs.

On the other hand, in the case of measuring the B voltage while both the first switch and the second switch of the battery pack are in the on state, a battery pack voltage are applied to both the A voltage and the B voltage, and, in this case, as indicated by an arrow (solid line) in <FIG>, interference between the first pack and the second pack may occur. Therefore, as illustrated in <FIG>, the B voltage has to be sequentially measured for each battery pack.

As described above, with the battery relay diagnostic device according to an embodiment of the present disclosure, it is possible to solve the problem of misdiagnosis by the influence between battery packs by performing diagnosis simultaneously or sequentially in consideration of interference by the on/off states of the relays of each battery pack.

<FIG> is a flowchart illustrating a battery relay diagnostic method according to an embodiment of the present disclosure.

A battery relay diagnostic method according to an embodiment of the present disclosure, which is illustrated in <FIG>, is a diagnostic method for a battery system including a charge and discharge controller connected between a plurality of battery packs connected in parallel and a load part and controlling charge and discharge of battery cell modules included in the battery packs, and the battery packs including the battery cell module including a plurality of battery cells and a switching unit including a first switch provided between a positive (+) terminal of the battery cell module and the load part and a second switch provided between a negative (-) terminal of the battery cell module and the load part. In this case, the charge and discharge controller may include only one pre-charge circuit.

In addition, the battery relay diagnostic method may be a diagnostic method of performing diagnosis based on the on/off state of relays included in the battery pack (e.g., whether or not there is interference between the battery packs).

Referring to <FIG>, a voltage across the first switch are simultaneously measured for the plurality of battery packs when both the first switch and the second switch are open and are in the off state (S610).

Then, when the first switch and the second switch are in the off state, a voltage across a terminal of the first switch close to a (+) side of the battery cell module and a terminal of the second switch close to the load part is sequentially measured for each of the plurality of battery packs (S620).

Then, when the first switch is in the off state and the second switch is closed and is in the on state, the voltage across the terminal of the first switch close to the (+) side of the battery cell module and the terminal of the second switch close to the load part is simultaneously measured for the plurality of battery packs (S630).

Then, when both the first switch and the second switch are closed and are in the on state, the voltage across the first switch is sequentially measured for each of the plurality of battery packs (S640).

On the other hand, although not illustrated in <FIG>, the battery relay diagnostic method according to an embodiment of the present disclosure may include generating a warning notification when the diagnostic unit determines that an abnormality occurs in at least one of the first switch and the second switch in the plurality of battery packs.

As described above, with the battery relay diagnostic method of the present disclosure, it is possible to reduce cost and simplify control logic by minimizing the configuration of the pre-charge circuit of battery packs connected in parallel, and to prevent misdiagnosis by performing diagnosis according to a state of each relay in consideration of the effect of interference from other battery packs connected in parallel.

<FIG> is a diagram illustrating a hardware configuration of a battery relay diagnostic device according to an embodiment of the present disclosure.

Referring to <FIG>, a battery relay diagnostic device <NUM> may include a microcontroller (MCU) <NUM> controlling various processes and configurations, a memory <NUM> in which operating system programs and various programs (e.g., a battery relay diagnostic algorithm program capable of diagnosing the state of the first switch and the second switch, and a battery switching control program capable of controlling a switch in the battery pack) are recorded, an input/output interface <NUM> for providing an input interface and an output interface through which data of the battery cell module and/or the switching element, such as voltage, current, and temperature, can flow, and a communication interface <NUM> capable of communicating with the outside through a wired or wireless communication network. As described above, the computer program according to the present disclosure may be recorded in the memory <NUM> and processed by the microcontroller <NUM>, so that it may be implemented as a module that performs each functional block illustrated in <FIG>.

In the above, the present disclosure has been described as a structure without the pre-charge circuit in the battery pack; however, the principle applied to the present disclosure is to be applied in the same way even for a battery with a pre-charge.

In the description above, although all components constituting the aspects of the present disclosure have been described as being combined into one unit or operated in combination, the present disclosure is not necessarily limited to such aspects. That is, within the objective scope of the present disclosure, one or more components may be selectively and operatively combined in any number.

In addition, terms such as "include", "comprise", or "have" described above mean that the corresponding component can be present unless otherwise stated, and thus it should be construed that other components may be further included rather than excluding other components. All terms including technical or scientific terms have the same meaning as commonly understood by those of ordinary skill in the art to which the embodiments of the present disclosure belong, unless otherwise defined. Terms commonly used such as those defined in dictionaries should be interpreted as having a meaning that is consistent with their meaning in the context of the related art and will not be interpreted in an idealized or overly formal sense unless expressly so defined in the present disclosure.

Claim 1:
A battery system (<NUM>) comprising:
a plurality of battery packs (<NUM>) connected in parallel, wherein a battery pack of the battery packs (<NUM>) includes a battery cell module (<NUM>) including a plurality of battery cells and a switching unit (<NUM>) including a first switch provided between a positive terminal of the battery cell module (<NUM>) and a load part and a second switch provided between a negative terminal of the battery cell module (<NUM>) and the load part;
a charge and discharge controller (<NUM>) connected between the plurality of battery packs (<NUM>) and the load part, the charge and discharge controller (<NUM>) being configured to control charge and discharge of the plurality of battery packs (<NUM>); and
a battery relay diagnostic device (<NUM>) for diagnosing the battery system (<NUM>), the battery relay diagnostic device (<NUM>) comprising:
a switching controller (<NUM>) configured to control a current applied to the battery cell module (<NUM>) by controlling on/off of the switching unit (<NUM>); and
a diagnostic unit (<NUM>) configured to perform diagnosis on the first switch and the second switch based on an on/off state of the first switch and the second switch,
wherein the diagnostic unit (<NUM>) is configured to perform diagnosis simultaneously or sequentially on the first switch and the second switch in an order determined in consideration of interference between the plurality of battery packs (<NUM>).