Patent ID: 12243986

DETAILED DESCRIPTION OF THE EMBODIMENTS

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 an overlapped description thereof will be omitted. The terms “module” and “unit” for components used in the following description are used only in order to make the specification easier. Therefore, these terms do not have meanings or roles that distinguish them from each other by 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 and spirit of the present invention.

Terms including ordinal 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 others.

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 another component or be connected or coupled to another component with the other 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 or coupled to another component without the other component intervening therebetween.

It will be further understood that terms “comprises” 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.1shows a system for providing a wireless communication method in a battery pack according to an embodiment.

Referring toFIG.1, the system for providing a wireless communication method in a battery pack includes an external terminal1and a vehicle system2.

The external terminal1may be a portable terminal possessed by a driver who gets on the vehicle. For example, when the driver gets in the vehicle and turns on the vehicle system2, the external terminal1and the vehicle system2may perform a wireless communication with a predetermined communication module. The communication module may be a communication module such as Bluetooth, Wi-Fi, or Zigbee.

The external terminal1may scan a plurality of channels in a frequency bandwidth and may measure noise types and noise intensities of the channels to generate first channel scan information. For example, when the vehicle system2is turned on, the external terminal1may include an application for generating the first channel scan information and transmitting the same to the vehicle system2for respective predetermined periods or in real-time.

Depending on embodiments, the frequency bandwidth may include an industrial scientific medical (ISM) bandwidth. The ISM bandwidth is a frequency bandwidth that is allocated to the fields of the industry, science, and medical treatments, and is usable without additional allowance of usage. A common ISM bandwidth is globally established to the bandwidths of 900 MHZ, 2.4 GHZ, and 5.7 GHZ. For example, the Bluetooth and the Zigbee use one kind of the frequency bandwidth (2.4 GHZ), and the Wi-Fi uses two kinds of the frequency bandwidths (2.4 GHZ and 5 GHZ).

The ISM bandwidth is used by various wireless communication devices, so it has a trouble of deterioration of performance caused by communication interference. To prevent the communication interference, the communication protocol such as the Bluetooth, the Wi-Fi, or the Zigbee using the ISM bandwidth performs the communication according to a frequency hopping method. The frequency hopping method represents a communication method for dividing a frequency bandwidth in use into a plurality of channels with a predetermined bandwidth, quickly moving among the channels according to a specific pattern (hereinafter, a hopping sequence), dividing data, and transmitting the same.

The vehicle system2includes a control device10and a battery pack20.

The control device10generally controls the vehicle system2, and for example, it may be an electronic control unit (ECU) but is not limited thereto.

According to an embodiment, the control device10may include a first communication device for performing wireless communication with the external terminal1, and a second communication device for performing vehicle communication with the battery pack20. The first communication device may include a wireless communication module such as the Bluetooth, Wi-Fi, or Zigbee. The second communication device may include a vehicle communication module such as a controller area network (CAN), a local interconnect network (LIN), or a FlexRay used to communication in the vehicle.

The control device10may receive first channel scan information from the external terminal1through the first communication module and may transmit the first channel scan information to the battery pack20through the second communication module.

The battery pack20includes a master battery management system (BMS)100and a slave BMS200.

The battery pack includes a plurality of battery modules (not shown) in addition to the master BMS100and the slave BMS200. The respective battery modules include a plurality of battery cells electrically connected in series. For example, the battery pack may be mounted on the vehicle to supply power and drive a motor or may supply power so that various electronic devices, such as audio units or air conditioners, may be operated. Here, the vehicle may be an electric vehicle (EV), and a hybrid vehicle (HEV or PHEV) receiving driving power from the battery pack.

The battery pack20communicates with various external electronic devices according to the vehicle communication method such as the CAN, the LIN, or the FlexRay, and depending on embodiments, electronic devices in the battery pack20may perform communication according to the wireless communication method following the frequency hopping method. According to an embodiment, the master BMS100is installed in the battery pack20, it may communicate with the external control device10according to a vehicle communication method such as the CAN communication, and it may communicate with the internal slave BMS200according to a wireless communication method such as the frequency hopping method. The slave BMS200is installed in the battery pack20, it may not directly communicate with the outside, and it may communicate with the master BMS100according to the wireless communication method following the frequency hopping method.

Performance of the wireless communication is not determined by absolute signal intensity but may be determined by a ratio value of signal intensity to noise intensity, that is, relative signal intensity. Mean power (signal transmission power) of signals is changed by an amplifier or an attenuator, and noise is added thereto to degrade a transmission characteristic, so it is difficult to use the mean power as an index of performance of the wireless communication. That is, the performance of the wireless communication may be determined by a signal-to-noise ratio (SNR).

The SNR is a measure for quantitatively indicating an influencing force of noise to the signal carrying information, showing a degree of how high a power level a signal level has compared to a noise level. That is, signals generally coexist with noise. The influence of noise to the signal may be quantitatively found by the SNR.

SNR=10⁢log⁢PSPN(Equation⁢1)

Equation 1 calculates the SNR. PSis a mean signal transmission power, PNis a mean noise power, and a unit of the SNR may be decibels (dB). Referring to Equation 1, the SNR signifies that the influence of noise is less as the value becomes bigger.

For example, an excellent SNR level of audio may be equal to or greater than 40 dB (preferably 60 dB), and an excellent SNR level of video may be equal to or greater than 45 dB (preferably 55 dB). According to an embodiment, in the case of the data mutually transmitted and received between the master BMS100and the slave BMS200, the excellent SNR level may be set by an upper control device such as the control device10.

The master BMS100may integrally control a plurality of slave BMSs200_1,200_2, . . . ,200_N. For example, the master BMS100may perform wireless communication with the slave BMSs200to receive battery information and transmit instructions. The battery information may include information (e.g., a cell current, a cell voltage, a cell temperature, etc.,) measured by the slave BMS200and information (e.g., an SOC (State of Charge) and an SOH (State of Health)) estimated by the slave BMS200.

According to an embodiment, the master BMS100may generate a frequency hopping sequence and may perform wireless communication with the slave BMS200according to the frequency hopping sequence. For example, the master BMS100may select a plurality of hopping channels to be used in the frequency hopping method from among a plurality of channels CH_1to CH_N existing in the ISM bandwidth as frequency bandwidth used in the wireless communication, and may calculate signal intensities of the respective hopping channels to generate a frequency hopping sequence.

The frequency hopping method is a communication method for preventing deterioration of communication quality caused by signal interference with another communication device using the same frequency bandwidth, that is, the ISM bandwidth. That is, the frequency hopping method is a communication method for dividing the frequency bandwidth into frequencies with predetermined sizes to have a plurality of channels with different frequencies, and for dividing data and transmitting the divided data while changing the channels.

For example, when the ISM bandwidth is divided into ten channels of the first channel CH_1to the tenth channel CH_10, the master BMS100changes the channels to the first channel CH_1, the third channel CH_3, the eighth channel CH_8, etc., according to a predetermined pattern, divides the data, and transmits the divided data, thereby reducing or solving the mutual interference of the signal. The predetermined pattern may be a hopping sequence.

The master BMS100may select the channel having noise intensity that is equal to or less than a reference value as a hopping channel from among a plurality of channels belonging to the frequency bandwidth. For example, from among the ten divided channels of the first channel CH_1to the tenth channel CH_10in the ISM bandwidth, the master BMS100may discard the channel with high power density by noise and may select the channel with power density by noise that is equal to or less than a reference value as hopping channel. The noise in this instance includes all the signals excluding the data transmitted and received between the master BMS100and the slave BMS200, and for example, it may include signals transmitted through the channel by the Bluetooth, the Wi-Fi, or the Zigbee.

When a case of the battery pack20is made of a metal, some of the noise existing outside the battery pack20is blocked and is not transmitted into the battery pack20. That is, the inside of the battery pack20is influenced by the external noise, and it is difficult to clearly distinguish external noise types and noise intensities in the battery pack20. According to an embodiment, the master BMS100may select the hopping channel based on the first channel scan information generated by scanning the frequency bandwidth outside the battery pack20. Detailed descriptions will be provided below with reference toFIG.2andFIG.3.

The master BMS100may calculate the signal intensity when the hopping channel transmits and receives data, based on the noise intensity of the channel selected as the hopping channel and the predetermined SNR. The signal intensity may be power of the signal averaged with respect to time and may be determined by a data transmitting device. For example, when predetermined signal intensity is big, the slave BMS200must receive much power from the battery module so as to transmit data to the master BMS100.

According to an embodiment, the master BMS100may put the noise intensity and the SNR into Equation 1 to calculate the signal intensity. The noise intensity may be noise power, and the signal intensity may be signal transmission power. For example, when the hopping channels respectively have different noise power, the master BMS100may calculate the signal transmission power for the respective hopping channels.

The hopping channels are used in the wireless communication in the battery pack20, so according to an embodiment, the master BMS100may scan the frequency bandwidth in the battery pack20to generate second channel scan information and may calculate the signal transmission power based on the noise power of the hopping channel included in the second channel scan information. That is, the master BMS100may optimally calculate the signal transmission power based on the noise power measured in an environment in which the wireless communication is performed. Unnecessary power consumption may then be reduced. Detailed descriptions will be provided below with reference toFIG.2andFIG.3.

The slave BMS200is a system electrically connected to a battery module (not shown) and measuring a state of the battery module and managing the state thereof. For example, the slave BMS200may predict the state of charge (SOC) of the battery cell and may perform battery cell balancing. According to an embodiment, the slave BMS200may perform wireless communication with the master BMS100according to the frequency hopping sequence.

The slave BMS200receives power for transmitting data from the battery module. For example, when big signal transmission power is set, power for performing the wireless communication (for example, the slave BMS200transmits battery information to the master BMS100) also becomes bigger. The battery module may then be quickly discharged.

FIG.2shows a configuration of a master BMS shown inFIG.1.

Referring toFIG.2, the master BMS100includes a communicator110, a channel analyzer130, a storage unit150, and a control unit170.

The communicator110may include a first communication module communicating with the control device10, and a second communication module communicating with the slave BMS200.

The first communication module may communicate with the control device10by control of the control unit170to receive the first channel scan information and may store the first channel scan information in the storage unit150. For example, the first communication module may include a vehicle communication module such as a controller area network (CAN), a local interconnect network (LIN), or a FlexRay used to the communication in the vehicle.

The first channel scan information may be generated by an external terminal1positioned outside the battery pack20. For example, the first channel scan information may include a first noise type and first noise power of the respective ten channels of the first channel CH_1to the tenth channel CH_10included in the ISM bandwidth.

The second communication module may perform wireless communication with the slave BMS200according to the frequency hopping sequence by control of the control unit170. The frequency hopping sequence may be generated by the control unit170and may be stored in the storage unit150.

The channel analyzer130may scan a plurality of channels of a frequency bandwidth and may measure a second noise type and second noise power of the channels to generate second channel scan information. For example, when the vehicle system2is turned on, the channel analyzer130may generate second channel scan information and transmit the same to the control unit170for predetermined periods or in real-time. The frequency bandwidth may be the ISM bandwidth.

The second channel scan information may be generated by the channel analyzer130positioned inside the battery pack20. For example, the second channel scan information may include a second noise type and second noise power of the respective ten channels of the first channel CH_1to the tenth channel CH_10included in the ISM bandwidth. According to an embodiment, first channel scan information and second channel scan information are respectively generated outside and inside the battery pack20, so the first noise power and the second noise power of the respective first channel CH_1to the tenth channel CH_10may be different from each other.

The signal according to an embodiment may include the data transmitted and received between the master BMS100and the slave BMS200, and the noise may include the signals transmitted and received by other devices that are not the master BMS100and the slave BMS200. Therefore, measured signals for respective channels included in the first channel scan information and the second channel scan information may be noise.

The storage unit150may store a reference SNR value that becomes the reference to determine the performance of wireless communication performed in the battery pack20. The storage unit150may store the first channel scan information received from the control device10through the first communication module and the second channel scan information generated by the channel analyzer130.

According to an embodiment, the control device10may predetermine a minimum SNR on the data transmitted and received between the master BMS100and the slave BMS200, that is, the reference SNR value (e.g., 5 dB). For example, the control unit170may transmit the data to the slave BMS200with signal transmission power that allows the reference SNR value to be at least 5 dB.

The control unit170selects a plurality of hopping channels based on the first channel scan information and calculates signal intensities of the respective hopping channels based on the second channel scan information and the reference SNR value to generate a frequency hopping sequence.

The control unit170may select a plurality of hopping channels to be used in the frequency hopping method from among a plurality of channels CH_1to CH_N existing in the ISM bandwidth based on the first noise type and the first noise power measured outside the battery pack20.

For example, the channels that have the first noise power that is equal to or less than a reference value from among the first channel CH_1to the tenth channel CH_10existing in the ISM bandwidth may be the first channel CH_1, the third channel CH_3, and the eighth channel CH_8based on the first channel scan information. The control unit170may select the first channel CH_1, the third channel CH_3, and the eighth channel CH_8as hopping channels.

For another example, the control unit170may select the channels that have the first noise power that is equal to or less than a reference value and do not include a specific noise type from among the first channel CH_1to the tenth channel CH_10existing in the ISM bandwidth as hopping channels. That is, when the channel that has low power density by the first noise is used by noise (the Bluetooth, the Wi-Fi, the Zigbee, etc.), the control unit170may not select the corresponding channel as a hopping channel.

The control unit170may calculate signal transmission power of the respective hopping channels based on the second noise power measured in the battery pack20and the reference SNR value.

When the signal transmission power of the actually transmitted data is high, that is, when the SNR value that is a signal transmission power to noise power ratio increases, a receiving side may clearly understand the signal. However, the case in which the data are transmitted with more than appropriate signal transmission power provides wireless communication performance that is not much different from the case in which the data are transmitted with the optimal signal transmission power, but the slave BMS200has a drawback of using much power of the battery module to transmit the data. According to an embodiment, the control unit170may calculate the signal transmission power of the data transmitted and received in the battery pack20based not on the first noise power measured outside the battery pack20, but on the second noise power measured inside the battery pack20.

For example, the control unit170may extract second noise power of the hopping channel included in the second channel scan information and may calculate the signal transmission power of the hopping channel by substituting the extracted second noise power into Equation 1. When the first channel CH_1, the third channel CH_3, and the eighth channel CH_8are selected as hopping channels, the second noise power of the respective first channel CH_1, the third channel CH_3, and the eighth channel CH_8may be extracted from the second channel scan information, and the extracted second noise power may be substituted into Equation 1 to calculate the signal transmission power of the first channel CH_1, the third channel CH_3, and the eighth channel CH_8.

The control unit170may generate a frequency hopping sequence based on the selected hopping channels and the signal transmission power of the respective hopping channels. For example, the control unit170may configure the first channel CH_1, the third channel CH_3, the first channel CH_1, the eighth channel CH_8, and the third channel CH_3as one set. The frequency hopping sequence may be configured in order of repeating the channel set.

FIG.3shows a flowchart of a wireless communication method in a battery pack according to an embodiment.

A wireless communication method in a battery pack and a master BMS providing the method will now be described with reference toFIG.1toFIG.3.

The master BMS100may receive the first channel scan information generated by the external terminal1positioned outside the battery pack20through the control device10(S110).

The external terminal1may scan a plurality of channels belonging to the frequency bandwidth used to the wireless communication in the battery pack20to generate first channel scan information and may transmit the first channel scan information to the control device10. The control device10may transmit the first channel scan information to the master BMS100.

The external terminal1may be a portable terminal possessed by the driver getting in the vehicle. For example, when the driver gets in the vehicle to turn on the vehicle system2, the external terminal1and the vehicle system2may perform wireless communication with a predetermined communication module. The communication module may be a communication module such as the Bluetooth, the Wi-Fi, or the Zigbee.

The external terminal1may scan a plurality of channels of the frequency bandwidth and may measure a first noise type and first noise intensity of the respective channels to generate first channel scan information. The frequency bandwidth may include the industrial scientific medical (ISM) bandwidth. The ISM bandwidth is a frequency bandwidth that is allocated to the fields of the industry, science, and medical treatments, and is usable without additional allowance of usage.

For example, the first channel scan information may include a first noise type and first noise power of the respective ten channels of the first channel CH_1to the tenth channel CH_10included in the ISM bandwidth.

The master BMS100may select the hopping channel used to the frequency hopping method based on the first channel scan information (S130).

According to an embodiment, the master BMS100may compare a reference value and first noise intensities of the respective channels included in the first channel scan information, and may select the channel having first noise intensity that is less than the first reference value from among a plurality of channels as a hopping channel.

For example, the channels having first noise power that are equal to or less than a reference value from among the first channel CH_1to the tenth channel CH_10existing in the ISM bandwidth may be the first channel CH_1, the third channel CH_3, and the eighth channel CH_8based on the first channel scan information. The master BMS100may select the first channel CH_1, the third channel CH_3, and the eighth channel CH_8as hopping channels.

According to another embodiment, the master BMS100may compare a reference value and first noise intensities of the respective channels included in the first channel scan information, and may select the channels that have first noise intensity that is less than a first reference value from among the channels, and that do not include predetermined noise in the first noise type included in the first channel scan information as hopping channels.

For example, when based on the first channel scan information, the channels that have first noise power that is equal to or less than a reference value from among the first channel CH_1to the tenth channel CH_10existing in the ISM bandwidth may be the first channel CH_1, the third channel CH_3, and the eighth channel CH_8. The type of the predetermined noise is a Bluetooth protocol, and the Bluetooth protocol may use the third channel CH_3based on the first channel scan information. The master BMS100may select the first channel CH_1and the eighth channel CH_8as hopping channels.

The master BMS100may calculate signal intensity of the hopping channel based on the second channel scan information and the reference SNR value on the wireless communication (S150).

The master BMS100may scan a plurality of channels belonging to the frequency bandwidth in the battery pack20to generate second channel scan information. The second channel scan information may include second noise intensity of the channels.

The master BMS100may calculate the signal intensity satisfying the reference SNR value for the second noise intensity of the hopping channel included in the second channel scan information. The master BMS100may determine the calculated signal intensity to be signal intensity of the hopping channel.

For example, the master BMS100may substitute the second noise intensity of the first channel CH_1selected as a hopping channel and the reference SNR value into Equation 1, and may calculate signal intensity of the first channel CH_1. The master BMS100may substitute the second noise intensity of the third channel CH_3selected as a hopping channel and the reference SNR value into Equation 1, and may calculate signal intensity of the third channel CH_3. The master BMS100may substitute the second noise intensity of the eighth channel CH_8selected as a hopping channel and the reference SNR value into Equation 1, and may calculate the signal intensity of the eighth channel CH_8.

The master BMS100may generate a hopping sequence of the frequency hopping method based on the hopping channel and the signal intensity of the hopping channel (S170).

The master BMS100may set an order so that the first channel CH_1, the third channel CH_3, and the eighth channel CH_8that are hopping channels may have an arbitrary pattern. For example, the master BMS100may configure the first channel CH_1, the third channel CH_3, the first channel CH_1, the eighth channel CH_8, and the third channel CH_3as a channel set. The master BMS100may generate a hopping sequence in order of repeating the channel set. That is, hopping sequence may be repeated in like order of the first channel CH_1, the third channel CH_3, the first channel CH_1, the eighth channel CH_8, the third channel CH_3, the first channel CH_1, the third channel CH_3, the first channel CH_1, the eighth channel CH_8, the third channel CH_3, the first channel CH_1, the third channel CH_3, the first channel CH_1, the eighth channel CH_8, and the third channel CH_3, and may be set to transmit and receive the data according to the signal transmission power for the respective channels.

The master BMS100may perform synchronization with the slave BMS200based on the hopping sequence so that it may be positioned in the same hopping channel at the same time with the slave BMS200(S190).

To receive the data from the slave BMS200, the master BMS100must be tuned with a specific frequency at a specific time by using the same hopping sequence as the hopping sequence used when the slave BMS200transmits data. That is, the master BMS100may resort the data transmitted by the slave BMS200when synchronized with the slave BMS200based on the hopping sequence.

While this invention has been described in connection with what is presently considered to be practical embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.