WIRELESS COMMUNICATION SYSTEM

Abstract

A wireless communication system is provided, which is integrated into a vehicle's battery pack. The wireless communication system comprises: a battery management device, which includes an antenna and a cable, each emitting a first radio signal into space, with the antenna and cable each emitting a receive signal based on a second radio signal propagating through space; and several battery data devices, provided in a one-to-one correspondence to several battery modules contained in the battery pack, the battery data devices being able to communicate wirelessly with the battery management device via the antenna or the cable. The battery management device attenuates or interrupts the receive signal from the cable when wireless communication with the battery data device is taking place via the antenna.

Description

Technical area

[0001] The present invention relates to a wireless communication system that performs wireless communication in a battery pack mounted in a vehicle. Technical background

[0002] A battery pack used for electric vehicles, such as electric cars and hybrid cars, comprises multiple battery modules. Each battery module consists of several single battery cells, such as lithium-ion cells, connected in series or in series and parallel. Generally, an electric vehicle battery pack is equipped with a battery controller that performs charge / discharge control for each battery module. The battery controller measures the condition of the single battery cells contained in each battery module, estimates the capacity of each single cell based on the measurement results, and performs charge / discharge control for each battery module to prevent overcharging or overdischarging.

[0003] For the above-described battery pack for electric vehicles, a battery control device with a wireless configuration has been proposed to achieve weight reduction, cost reduction, greater freedom of layout of devices within the vehicle, and the like. A battery control device with a wireless configuration, i.e., a wireless battery control device, includes, for example, a plurality of battery data devices (slaves) each provided for each corresponding battery module and measuring a state of each individual battery cell of the battery module, a battery management device (master) that receives and analyzes information transmitted from the plurality of slaves and controls each battery module, and a plurality of wireless devices that perform wireless communication between each slave and the master.Such a wireless battery control device offers the advantages described above, but it raises the possibility that a zero point (a point where wireless performance drops sharply) may develop under the influence of multiple paths created by reflection from a metal or the like in the battery pack. The development of the zero point raises concerns that normal wireless communication between the slave and the master at the zero point may not be possible.

[0004] As a known technique in this technical field, PTL 1 discloses a method in which a leaky coaxial cable and an antenna are jointly used in wireless communication and the reception performance is improved by causing the leaky coaxial cable and the antenna to operate according to a space diversity method. Citation listPatent literature

[0005] PTL 1: JP 2011-146909 A Summary of the inventionTechnical problem

[0006] When the invention described in PTL 1 is applied to wireless communication in a battery pack, sufficient distance cannot be provided between the leaky coaxial cable and the antenna, so that the effects of the space diversity method may prove insufficient.

[0007] The present invention was conceived in view of the above-described problem encountered in the conventional technology. A primary object of the present invention is to establish stable wireless communication in a battery pack. Solution to the problem

[0008] A wireless communication system according to a first aspect of the present invention is installed in a battery pack of a vehicle. The wireless communication system includes: a battery management device having an antenna and a cable, each emitting a first radio signal into the space, the antenna and the cable each outputting a reception signal based on a second radio signal propagating through the space; and a plurality of battery data devices provided in one-to-one correspondence with a plurality of battery modules included in the battery pack, the battery data devices capable of wirelessly communicating with the battery management device via the antenna or the cable. The battery management device attenuates or interrupts the reception signal from the cable when wirelessly communicating with the battery data device via the antenna.

[0009] A wireless communication system according to a second aspect of the present invention is installed in a battery pack of a vehicle. The wireless communication system includes a battery management device having a cable acting as an antenna, and a plurality of battery data devices provided in one-to-one correspondence with a plurality of battery modules included in the battery pack, wherein the battery data devices can wirelessly communicate with the battery management device via the cable. Advantageous effects of the invention

[0010] According to the present invention, stable wireless communication can be performed in the battery pack. Brief description of the drawings

[0011] They show: Fig. 1 shows an example of an overall configuration of a wireless communication system according to a first embodiment of the present invention, Fig. 2 shows a modification of the wireless communication system according to the first embodiment of the present invention, Fig. 3 an example of the structure of a cable, Fig. 4 an example of the overall structure of a conventional wireless communication system, Fig. 5 shows an example of the communication timing during normal communication in the conventional wireless communication system, Fig. 6 shows an example of the communication timing during abnormal communication in the conventional wireless communication system, Fig. 7 shows an example of the communication timing in the wireless communication system according to the present invention, Fig. 8 is a diagram explaining radio signal interference occurring between an antenna and a cable, Fig. 9 is a flowchart of an example of a setting procedure for communication means used by a battery management device, Fig. 10 shows an example of reception levels of transmission signals transmitted by battery data devices, respectively, Fig. 11 shows a first arrangement example of the wireless communication system in the battery pack, Fig. 12 a second arrangement example of the wireless communication system in the battery pack, Fig. 13 shows an example of a configuration of a terminating resistor according to the first embodiment of the present invention, Fig. 14 shows an example of an overall configuration of a wireless communication system according to a second embodiment of the present invention, Fig. 15 shows an example of an overall configuration of a wireless communication system according to a third embodiment of the present invention, Fig. 16 shows a modification of the wireless communication system according to the third embodiment of the present invention, and Fig. 17 shows an example of a configuration of a termination resistor according to the third embodiment of the present invention. Description of embodiments

[0012] Embodiments of the present invention will be described below. The following embodiments of the present invention are described as examples in which a wireless communication system is incorporated into a battery control device that monitors a battery system used in a vehicle such as an electric vehicle (BEV). It should be noted that the present invention can be applied not only to a battery system used in a BEV, but also more generally to battery systems used in other vehicles such as plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs), and rail vehicles, and various power storage devices for applications other than those requiring vehicle battery systems.

[0013] The following embodiments are each described assuming that a power storage / discharge device treated as a minimum control unit in the battery system is a lithium-ion battery with an operating voltage ranging from, for example, 2.5 V to 4.5 V. However, a device other than a lithium-ion battery may be used to constitute the battery system, provided it can store and discharge electric charge. Any device may be used as long as its state can be monitored and controlled by using the battery control device according to the present invention, and its use can be restricted when its state of charge (SOC) is too high (overcharge) or too low (overdischarge). In the following description, such devices are generally referred to as a single battery or a single battery cell. (First embodiment)

[0014] A first embodiment of the present invention will be described below with reference to drawings.

[0015] Fig. 1 shows an example of an overall configuration of a wireless communication system according to the first embodiment of the present invention. Fig. 1 shown wireless communication system 1 is integrated in a battery pack 10 (see Fig. 11 and Fig. 12) which is incorporated in a vehicle, and has n (n denotes a positive natural number) battery data devices 200 and a battery management device 300. In Fig. 1, in order to distinguish the battery data device 200 from other components, additional characters from 1 to n are appended to the reference numerals for the respective battery data devices 200 (for example, battery data device 200-1).

[0016] The battery data devices 200 are each connected to n battery modules 101 contained in the battery pack 10. In other words, the battery data devices 200 are provided in the wireless communication system 1 in a one-to-one correspondence with the plurality of battery modules 101 contained in the battery pack 10. Each battery module 101 consists of a plurality of individual battery cells 100 connected in series or in series and parallel. Fig. 1, as in the case of the battery data devices 200, in order to distinguish the battery modules 101 from other components, additional characters from 1 to n are appended to the reference numbers of the respective battery modules 101 (for example, battery module 101-1).

[0017] Each battery data device 200 includes a single-cell state measuring device 201, a wireless device 202, and an antenna 210. The single-cell state measuring device 201 measures, for example, the states of a plurality of single-cell batteries 100 contained in the corresponding battery module 101, as well as voltages, temperatures, and the like of the single cells 100, and outputs the measurement results to the wireless device 202. The wireless device 202 modulates measurement data based on the measurement results output by the single-cell state measuring device 201 to generate a transmission signal at a radio frequency and outputs the transmission signal to the antenna 210. The antenna 210 emits a radio signal into the room based on the transmission signal output by the wireless device 202, thereby wirelessly transmitting the radio signal to the battery management device 300. Fig. 1, the single-cell condition measuring device 201, the wireless device 202, and the antenna 210 included in each battery data device 200 each have the same suffix as that appended to the battery data device 200 (e.g., single-cell condition measuring device 201-1, wireless device 202-1, and antenna 210-1).

[0018] The battery management device 300 includes a battery monitoring device 301, a wireless device 302, a distributor 303, a switch 304, an attenuator 305, an antenna 310, a cable 320, and a terminating resistor 330. The antenna 310 receives a radio signal transmitted from each battery data device 200, which propagates through the space to the antenna 310, and outputs a reception signal to the wireless device 302 based on the radio signal. The cable 320 receives a radio signal transmitted from each battery data device 200, which propagates through the space to the cable 320, and, like the antenna 310, outputs a reception signal to the wireless device 302 based on the radio signal. The cable 320 will be described in detail later.

[0019] The wireless device 302 demodulates the received signal output from the antenna 310 or the cable 320 to generate measurement data indicating a state measurement result for each single battery cell 100 included in the battery module 101, which corresponds one-to-one to the battery data device 200, and outputs the measurement data to the battery monitoring device 301. Based on the measurement data output from the wireless device 302, the battery monitoring device 301 detects a state of each single battery cell 100 of the battery module 101, which corresponds one-to-one to the battery data device 200. This enables the battery management device 300 to detect a state of each battery module 101 in the battery pack 10.

[0020] Once the status of each battery module 101 has been detected, the battery monitoring device 301 generates a control signal for one of the battery modules 101 as needed, the control signal controlling the charging and discharging performed by each individual battery cell contained in a battery module 101, and outputs the control signal to the wireless device 302. The wireless device 302 modulates the control signal output by the battery monitoring device 301 to generate a transmission signal at a radio frequency and outputs the transmission signal to the antenna 310 and the cable 320. The antenna 310 and the cable 320 each emit a radio signal into the room based on the transmission signal output by the wireless device 302 and wirelessly transmit the radio signals to the battery data device 200.Therefore, wireless communication between each battery data device 200 and the battery management device 300 occurs via the antenna 310 or the cable 320.

[0021] The antenna 310 and the cable 320 are connected to the wireless device 302 via the distributor 303. The distributor 303 transmits reception signals output from the antenna 310 and the cable 320, respectively, to the wireless device 302 and distributes transmission signals output from the wireless device 302 to the antenna 310 and the cable 320.

[0022] The cable 320 is connected to the distributor 303 via a switch 304 and an attenuator 305. The attenuator 305 is a bidirectional attenuator that attenuates a radio frequency signal by a given attenuation level (for example, several tens of dB). The switching action of the switch 304 is controlled by the wireless device 302. When the switch 304 is switched to an off state (open state), a received signal output from the cable 320 is attenuated by the attenuator 305 and then input to the wireless device 302 via the distributor 303. When the switch 304 is switched to an on state (conductive state), the received signal output from the cable 320 is not attenuated by the attenuator 305 and is input to the wireless device 302 via the switch 304 and the distributor 303. The switching control of the switch 304 by the wireless device 302 will be described later.

[0023] The terminating resistor 330 is connected to the front end of the cable 320. The impedance of the terminating resistor 330 is equal to the input impedance of a transmit signal and the output impedance of a receive signal at the wireless device 302. This terminating resistor 330, which is connected to the cable 320 on the opposite side to the wireless device 302, performs an impedance match between the cable 320 and the wireless device 302. Although the terminating resistor 330 in the Fig. 1, it is also possible that it is not included in the wireless communication system 1.

[0024] Fig. 3 shows an example of the structure of the cable 320. As in Fig. As shown in Figure 3, the cable 320 is generally constructed such that the periphery of a conductor 321 is covered with an insulator 322, the periphery of which is covered with a sheath 323. When a current flows through the conductor 321, the conductor 321 in the cable 320 emits a radio signal into the space around the conductor 321. This radio signal propagating through the space around the conductor 321 generates a current flow in the conductor 321. The cable 320 accordingly acts as an antenna.

[0025] The structure of the cable 320 is not limited to the Fig. 3 is limited. For example, a cable that acts as an antenna by allowing a radio signal to enter and exit a flexible plate-like conductor may also be provided as cable 320. In addition, a cable of any structure that acts as an antenna may be used as cable 320.

[0026] In the above example, a case was described in which the reception signal output from the cable 320 is attenuated by the attenuator 305 and input to the wireless device 302 when the switch 304 of the battery management device 300 is switched to the off state. Fig. 1, the output of the received signal from the cable 320 to the wireless device 302 may, however, be in a Fig. 2 shown configuration can be interrupted.

[0027] Fig. 2 shows a modification of the wireless communication system according to the first embodiment of the present invention. According to the Fig. In the modification shown in Figure 2, the cable 320 in the battery management device 300 is connected to the distributor 303 via the switch 304. Therefore, when the switch 304 is switched to the open state, the reception signal output from the cable 320 is cut off and does not enter the wireless device 302. The battery management device 300 can be configured in this way.

[0028] The operation of the wireless communication system according to this embodiment is then evaluated by comparison with a Fig. 4 is described. Fig. Figure 4 shows an example of the overall structure of the conventional wireless communication system. Fig. The wireless communication system 1Z shown in Figure 4 differs from the one shown in Fig. 1 and Fig. 2 according to the first embodiment of the present invention in that the battery management device 300, which does not have the cable 320, performs wireless communication with each battery data device 200 only via the antenna 310.

[0029] Fig. 5 shows an example of the communication timing during normal communication in Fig. 4. In the wireless communication system 1Z, the battery management device 300 requests a measurement of a state of the battery module 101 from each battery data device 200, and each battery data device 200 responsively measures the state of each battery module 101 and transmits the measurement results to the battery management device 300. Accordingly, in Fig. 5, the operation timing of the battery management device 300 is expressed as "Master 300" and the operation timings of the battery data devices 200 are expressed as "Slave200-1", "Slave200-2", ... and "Slave200-n", respectively.

[0030] The battery management device 300 sends a request command to each battery data device 200. After receiving the request command from the battery management device 300, each battery data device 200 measures a state (voltage, temperature, etc.) of each single battery cell 100 of the battery module 101 corresponding to the battery data device 200 at time t0. Thereafter, at time t1, a battery data device 200-1 transmits data of the result of measuring the state of each single battery cell 100 to the battery management device 300. When the data transmitted from the battery data device 200-1 is received normally, the battery management device 300 returns ACK to the battery data device 200-1.

[0031] In the same way, at time t2, a battery data device 200-2 transmits data of the result of measuring the state of each single battery cell 100 to the battery management device 300, and at time t3, a battery data device 200-3 does the same. In this way, communication between each of the battery data devices 200 and the battery management device 300 occurs in a sequence until the last battery data device 200-n transmits data of the result of measuring the state of each single battery cell 100 to the battery management device 300 at time tn.

[0032] Now, assume a case where the battery management device 300 does not normally receive the data transmitted from the battery data device 200-2 at time t2. In this case, the battery management device 300 returns NAK to the battery data device 200-2. After receiving the NAK signal, the battery data device 200-2 retransmits the data of the result of measuring the state of each single battery cell 100 to the battery management device 300. If the data retransmitted from the battery data device 200-2 is received normally, the battery management device 300 returns ACK to the battery data device 200-2.

[0033] Another case is assumed where a battery data device 200-3, which normally receives the data and returns ACK, transmits data to the battery management device 300 at time t3, but the battery data device 200-3 does not receive the ACK signal even after a given time has elapsed since the data transmission. In this case, the battery data device 200-3 retransmits the data of the result of measuring the state of each single battery cell 100 to the battery management device 300. When it normally receives the data retransmitted from the battery data device 200-3, the battery management device 300 returns ACK to the battery data device 200-3. When it normally receives the ACK signal from the battery management device 300, the battery data device 200-3 terminates the data transmission.

[0034] In this way, the battery management device 300 and each battery data device 200 repeat the above communication process during a communication period ranging from the time of transmission of the request command to time tn.

[0035] Fig. 6 shows an example of the communication timing during abnormal communication in Fig. 4 shown conventional wireless communication system 1Z. Fig. 6 shows an example of a case where data transmitted from the battery data device 200-3 to the battery management device 300 cannot be received normally by the battery management device 300. In such a case, the battery management device 300 cannot detect a state of a battery module 101-3 and therefore cannot perform normal charge / discharge control. If the battery data device 200-3 cannot receive a request command from the battery management device 300, the battery data device 200-3 does not transmit data to the battery management device 300. In this case, the battery management device 300 cannot detect the state of the battery module 101-3, as in the above case.

[0036] When a communication path between the battery management device 300 and the battery data device 200-3 is a zero point generated by multiple paths, the reception level of data transmitted from the battery data device 200-3 at the battery management device 300 drops sharply. Likewise, the reception level of a request command transmitted from the battery management device 300 at the battery data device 200-3 drops sharply. This may lead to the above-described case where normal communication cannot be consistently performed between the battery management device 300 and the battery data device 200-3.In general, the battery pack 10 includes a number of multiple arrangements of metal parts such as terminals of single battery cells 100 and various wires, and the electric waves reflected from these metal parts generate multiple paths, which inevitably leads to the development of a null point.

[0037] Fig. 7 shows an example of the communication timing in the wireless communication system according to the present invention. In Fig. 7, the battery management device 300 has the Fig. 1, the cable 320 of the battery management device 300 is arranged near the battery data device 200 corresponding to the zero point (in this example, the battery data device 200-3). For example, the distance between the cable 320 and the battery data device 200 is at most a few tens of centimeters.

[0038] The battery management device 300 transmits a first request command to each battery data device 200 except the battery data device 200-3 via the antenna 310. At this time, the wireless device 302 sets the switch 304 to the off state so that the attenuator 305 is located between the cable 320 and the wireless device 302, thereby reducing the level of the transmission signal output from the wireless device 302 to the cable 320.

[0039] Subsequently, the battery management device 300 transmits a second request command via the cable 320 to the battery data device 200-3, which is the device to be wirelessly communicated with using the cable 320. At this time, the wireless device 302 sets the switch 304 to the on state to bypass the attenuator 305, so that a transmission signal output from the wireless device 302 to the cable 320 is not attenuated.

[0040] Upon receiving the first or second request command from the battery management device 300, each battery data device 200 measures a state (voltage, temperature, etc.) of each single battery cell 100 of the battery module 101 corresponding to the battery data device 200 at time t0 after being in the standby state for a given time. Thereafter, at time t1, a battery data device 200-1 transmits data of the result of measuring the state of each single battery cell 100 to the battery management device 300. If the data transmitted from the battery data device 200-1 is received normally, the battery management device 300 returns ACK to the battery data device 200-1.

[0041] In the same way, at time t2, a battery data device 200-2 transmits data of the result of measuring the state of each single battery cell 100 to the battery management device 300, and at time t3, a battery data device 200-3 does the same. In this way, communication between each of the battery data devices 200 and the battery management device 300 occurs in a sequence until the last battery data device 200-n transmits data of the result of measuring the state of each single battery cell 100 to the battery management device 300 at time tn.

[0042] In this process, the battery management device 300 sets the switch 304 during a partial period for communication with each battery data device 200 communicated with via the antenna 310, that is, a partial period for communication with each of the battery data devices 200 except the battery data device 200-3 (in Fig. 7, each of the communication subperiods from time t1 to time tn, excluding time t3) is set to the off state to interpose the attenuator 305 between the cable 320 and the wireless device 302, thereby reducing the level of a reception signal output from the cable 320 to the wireless device 302. On the other hand, in a communication subperiod with the battery data device 200-3 (communication subperiod including time t3) communicated with via the cable 320, the switch 304 is set to the on state to bypass the attenuator 305, so that the reception signal output from the cable 320 to the wireless device 302 is not attenuated.

[0043] When the battery management device 300 in the wireless communication system 1 according to this embodiment communicates with each battery data device 200, the battery management device 300 sets the switch 304 to the on or off state depending on whether the antenna 310 or the cable 320 is used for communication, as described above. Accordingly, the attenuator 305 is located between the cable 320 and the wireless device 302 or not, depending on whether the switch 304 is in the on or off state. This is because, during communication via the antenna 310, radio signal interference occurring between the antenna 310 and the cable 320 must be suppressed. This will be explained below with reference to Fig. 8 described.

[0044] Fig. 8 is a diagram for explaining the radio signal interference occurring between the antenna 310 and the cable 320. Fig. 8(a) shows an example of the level of a reception signal input to the wireless device 302 in a case where the battery management device 300 sets the switch 304 to the on state so as not to leave the reception signal from the cable 320 attenuated during communication with the battery data device 200-1. Fig. 8(a) also shows an example of the level of a reception signal in a case where the switch 304 is set to the on state as in the communication with the battery data device 200-1, where the level of a reception signal is the level of a reception signal at the wireless device 302 during the communication between the battery management device 300 and the battery data device 200-3.

[0045] In the case of Fig. 8(a), during communication with the battery data device 200-1, the received signals from the antenna 310 and the cable 320 and entering the wireless device 302 interfere with each other, resulting in a lower signal-to-noise (S / N) ratio. As a result, the wireless device 302 is unable to normally receive the received signal from the antenna 310. On the other hand, during communication with the battery data device 200-3, the reception level of the received signal from the antenna 310 is low because a null point is generated by multiple paths. This allows the wireless device 302 to normally receive the received signal from the cable 320.

[0046] Fig. 8(b) shows an example of the level of a reception signal input to the wireless device 302 in a case where the battery management device 300 sets the switch 304 to the off state to attenuate the reception signal from the cable 320 during communication with the battery data device 200-1. As shown in Fig. 8(a) shows Fig. 8(b) also shows an example of the level of a reception signal in a case where the switch 304 is set to the on state, wherein the level of a reception signal is the level of a reception signal at the wireless device 302 during the communication between the battery management device 300 and the battery data device 200-3.

[0047] In the case of Fig. 8(b), the reception signal input from the cable 320 to the wireless device 302 is attenuated during communication with the battery data device 200-1, and therefore the reception signal-to-noise ratio is higher than the reception signal-to-noise ratio in the case of Fig. 8(a). As a result, the wireless device 302 is able to normally receive the reception signal from the antenna 310. When communicating with the battery data device 200-3, the level of the reception signal from the antenna 310 remains as in the case of Fig. 8(a) is low even when the switch 304 is set to the on state, and therefore the wireless device 302 can normally receive the reception signal from the cable 320.

[0048] As described above, during the communication sub-period for communicating with each battery data device 200 using the antenna 310, the battery management device 300 sets the switch 304 to the off state to attenuate signals input and output between the cable 320 and the wireless device 302. On the other hand, during the communication sub-period for communicating with each battery data device 200 using the cable 320, the battery management device 300 sets the switch 304 to the on state to prevent attenuation of signals input and output between the cable 320 and the wireless device 302. By controlling the switching operations of the switch 304 in this way, the battery management device 300 can suppress signal interference occurring between the antenna 310 and the cable 320.

[0049] In the wireless communication system 1 according to this embodiment, the battery management device 300 must be set in advance to determine whether the antenna 310 or the cable 320 is to be used for communication with each battery data device 200. A method for making this setting will be described below with reference to Fig. 9 described.

[0050] Fig. 9 is a flowchart of an example of a procedure for setting communication means used by the battery management device 300. In the wireless communication system 1 according to this embodiment, for example, in the manufacture of the battery pack 10 or prototypes thereof, the procedure according to the flowchart of Fig. 9 determines whether the antenna 310 or the cable 320 is used by the battery management device 300 when communicating with each battery data device 200.

[0051] The battery management device 300 sets the switch 304 to the off state to dispose the attenuator 305 between the cable 320 and the wireless device 302, thereby attenuating a transmission signal output from the wireless device 302 to the cable 320, and transmitting the attenuated transmission signal to each battery data device 200 (S100). Upon receiving the transmission signal transmitted from the battery management device 300 in step S100, each battery data device 200 performs data transmission in a given subperiod, as described with reference to Fig. 7 (S110). In step S110, the battery management device 300 receives data transmitted from each battery data device 200 and records the reception level of the data (S120).

[0052] After executing the processes from steps S100 to S120, a worker who manufactures the battery pack 10 and a developer who develops the battery pack 10 determine the arrangement of the cable 320 based on the reception level of the transmission signal from each battery data device, and the reception level is recorded in step S120 (S130). In this step, the arrangement of the cable 320 in the battery pack 10 is determined so that the cable 320 is located near a battery data device 200 whose transmission signal was not received in step S120 or has a reception level recorded as lower than a given value.

[0053] Subsequently, the battery management device 300 sets the switch 304 to the on state to bypass the attenuator 305 between the cable 320 and the wireless device 302, whereby a transmission signal output from the wireless device 302 to the cable 320 remains unattenuated and is transmitted to each battery data device 200 (S140). Upon receiving the transmission signal transmitted from the battery management device 300 in step S140, each battery data device 200 performs data transmission in a given subperiod, just as in step S110 (S150). In step S150, the battery management device 300 receives data transmitted from each battery data device 200 and records the reception level of the data (S160).

[0054] After executing the processes from steps S140 to S160, the worker and the developer determine a method for communication between the battery management device 300 and each battery data device 200 based on the reception level of the transmission signal from each battery data device 200, which is recorded in steps S120 and S160 (S170). In this step, the method for communication between the battery management device 300 and each battery data device 200 is set so that communication with a battery data device 200 whose transmission signal was received normally in step S120 is performed via the antenna 310, while communication with a battery data device 200 whose transmission signal was not received normally in step S120 but was received normally in step S160 is performed via the cable 320.Then, the setting according to the determined communication method is made on the battery management device 300 by making the setting on the wireless device 302 for the switching action of the switch 304 according to the determined communication method.

[0055] Fig. 10 shows an example of reception levels of respective transmission signals transmitted from the battery data device 200, wherein the reception levels in step S120 and step S160 are Fig. 9 were recorded. Fig. 10(a) shows an example of reception levels resulting from communication via the antenna 310, the reception levels being recorded in step S120, and Fig. 10(b) shows an example of reception levels resulting from communication via the cable 320, the reception levels being recorded in step S160.

[0056] In Fig. 10(a), the reception levels at the battery data devices 200-3 and 200-6 among the battery data devices 200-1 to 200-7 are not recorded. This indicates that the transmission signals from the battery data devices 200-3 and 200-6 were not received normally by the battery management device 300 under the influence of a multi-path generated zero point or the like.

[0057] In Fig. 10(b), on the other hand, the reception levels of the battery data devices 200-3 and 200-6 are recorded, as are the reception levels of other battery data devices 200. This indicates that the transmission signals from the battery data devices 200-3 and 200-6 were normally received by the battery management device 300 via the cable 320.

[0058] Based on the Fig. Based on the result of reception levels at the battery data device 200 shown in Fig. 10, the operator or the designer can set the communication means of the battery management device 300 such that the antenna 310 is used for communication with the battery data devices 200-1, 200-2, 200-4, 200-5, and 200-7, and the cable 320 is used for communication with the battery data devices 200-3 and 200-6.

[0059] It should be noted that the operation of the wireless communication system 1 is based on the Fig. 1 is similar to that which occurs when the battery management device 300 has the configuration shown in Fig. 2, although the operation of the wireless communication system 1 has been described above with reference to the Fig. 7 to 10. In this case, by setting switch 304 to the off state, wireless device 302 interrupts a signal input and output between wireless device 302 and cable 320, rather than attenuating the signal.

[0060] A method for securing the cable 320 in the battery pack 10 will then be described with reference to the Fig. 11 and Fig. 12 described.

[0061] Fig. 11 shows a first arrangement example of the wireless communication system 1 in the battery pack 10. Fig. 12 shows a second arrangement example of the wireless communication system 1 in the battery pack 10. In the Fig. 11 and Fig. 12 is (a) a perspective view of the battery pack 10, (b) a plan view of the battery pack 10, and (c) a front view of the battery pack 10.

[0062] As in the Fig. 11 and Fig. 12, the battery pack 10 has a housing 11 in the form of a large box. This housing 11 contains a plurality of battery modules 101, a plurality of battery data devices 200, each paired with the battery modules 101, and the battery management device 300. To clarify the layout within the battery pack 10, a portion of the housing 11 is shown in the plan views from FIGS. Fig. 11(b) and Fig. 12(b) and in the front views from the Fig. 11(c) and Fig. 12(c) not shown.

[0063] The battery modules 101 are connected to each other via a power supply line 12, and the cable 320 is located between parts of the power supply line 12. The Fig. 11 and Fig. 12 shows an example in which the battery pack 10 includes eight battery modules 101 (battery modules 101-1 to 101-8), and eight battery data devices 200 (battery data devices 200-1 to 200-8) are provided corresponding to the eight battery modules 101. However, the number of battery modules 101 and battery data devices 200 is not limited to eight.

[0064] A terminating resistor 330 is connected to the cable 320. In each of the arrangement examples from the Fig. 11 and Fig. 12, the terminating resistor 330 is arranged in the battery pack 10 such that the width of the terminating resistor 330 is greater than the arrangement interval of the battery modules 101 in the battery pack 10 and a connecting part connecting the cable 320 and the terminating resistor 330 is located between two adjacent battery modules 101. In particular, the terminating resistor 330 in the arrangement example of Fig. 11 is arranged so that the connecting part connecting the cable 320 and the terminating resistor 330 is located between the battery module 101-4 and the battery module 101-5 and the terminating resistor 330 is in the arrangement example from Fig. 12 is arranged such that the connecting part connecting the cable 320 and the terminating resistor 330 is located between the battery module 101-3 and the battery module 101-4. In these arrangements, wireless communication between the battery management device 300 and the battery data device 200-3 and the battery data device 200-6 can be performed via the cable 320.

[0065] The arrangement examples from the Fig. 11 and Fig. 12 does not show the antenna 210 that each battery data device 200 has, and the antenna 310 that the battery management device 310 has. These antennas can each be arranged at any position in the battery pack 10.

[0066] Fig. 13 shows an example of a configuration of the terminating resistor 330 according to the first embodiment of the present invention. According to this embodiment, the terminating resistor 330 is formed, for example, by connecting a conductor 321 of the cable 320 to a connecting part 332 of a printed circuit board 331 using a bonding material such as solder, as shown in FIG. Fig. 13. In addition to the connecting part 332, various electronic components for adjusting the input and output impedance can be mounted on the printed circuit board 331. As described above, the width w of the printed circuit board 331 corresponding to the width of the terminating resistor 330 is larger than the arrangement interval of the battery modules 101 in the battery pack 10. Therefore, the arrangement of the terminating resistor 330 in the battery pack 10 is consistent with the arrangement described above with reference to the Fig. 11 and Fig. 12, thereby enabling the cable 320 to be secured in a designated position.

[0067] The first embodiment of the present invention described above offers the following effects. (1) The wireless communication system 1 is formed in the battery pack 10 of a vehicle. The wireless communication system 1 includes the battery management device 300, which has the antenna 310 and the cable 320, each emitting a first radio signal into the space, the antenna 310 and the cable 320 each outputting a reception signal based on a second radio signal propagating through the space, and the plurality of battery data devices 200 provided in one-to-one correspondence with the plurality of battery modules 101 included in the battery pack 10. The battery data device 200 can wirelessly communicate with the battery management device 300 via the antenna 310 or the cable 320.The battery management device 300 attenuates or interrupts the reception signal from the cable 320 by setting the switch 304 to the off state when wirelessly communicating with the battery data device 200 via the antenna 310. This enables stable wireless communication in the battery pack 10. (2) The cable 320 includes at least the conductor 321 and emits the first radio signal based on a current flowing through the conductor 321 to an area around the conductor 321. Because of this configuration, wireless communication can be performed via the cable 320. (3) The battery management device 300 includes the terminating resistor 330 connected to the front end of the cable 320. The width w of the terminating resistor 330 is larger than the arrangement interval of the plurality of battery modules 101 in the battery pack 10, and the terminating resistor 330 is arranged in the battery pack 10 such that the connecting part of the cable 320 is located between two adjacent battery modules 101 among the plurality of battery modules 101. Due to this configuration, the cable 320 can be securely and easily attached to a designated position in the battery pack 10. (4) The terminating resistor 330 has the connecting part 332 electrically connected to the cable 320. Because of this structure, the cable 320 and the terminating resistor 330 can be easily electrically connected to enable the cable 320 to function as an antenna. (Second embodiment)

[0068] Fig. 14 shows an example of an overall configuration of a wireless communication system according to a second embodiment of the present invention. Fig. 14 is different from the wireless communication system 1 described in the first embodiment of FIGS. Fig. 1 and Fig. 2 in that the battery management device 300 does not have the antenna 310 and the battery management device 300 communicates with each battery data device 200 only via the cable 320.

[0069] According to this embodiment, the battery management device 300 includes the battery monitoring device 301, the wireless device 302, the antenna 310, the cable 320, and the terminating resistor 330. Unlike the first embodiment, the battery management device 300 according to this embodiment is not provided with the distributor 303, the switch 304, or the attenuator 305.

[0070] The cable 320 is located near the battery data device 200 corresponding to the zero point, and as in the first embodiment, the communication timing between the battery management device 300 and each battery data device 200 is similar to the communication timing according to the first embodiment, as shown in Fig. 5, that is, the communication timing during normal communication by the conventional wireless communication system 1Z.

[0071] According to the second embodiment of the present invention described above, the wireless communication system 1A is formed in the battery pack 10 of the vehicle, and includes the battery management device 300 having the cable 320 acting as an antenna, and the plurality of battery data devices 200 provided in one-to-one correspondence with the plurality of battery modules 101 included in the battery pack 10. The battery data devices 200 are capable of wirelessly communicating with the battery management device 300 via the cable 320. Due to this configuration, stable wireless communication can be performed in the battery pack 10 in the same manner as in the first embodiment. (Third embodiment)

[0072] Fig. 15 shows an example of an overall configuration of a wireless communication system according to a third embodiment of the present invention. Fig. The wireless communication system 1B shown in Fig. 15 differs from the wireless communication system 1 described in the first embodiment of Fig. 1 in that the battery management device 300 has two cables 320-1 and 320-2.

[0073] Similar to the cable 320 according to the first embodiment, the cable 320-1 is connected to the wireless device 302 via the switch 304, the attenuator 305, and the distributor 303. Therefore, when the switch 304 is set to the off state (open state), a reception signal output from the cable 320-1 is attenuated by the attenuator 305 and then input to the wireless device 302 via the distributor 303. When the switch 304 is set to the on state (conductive state), the reception signal output from the cable 320-1 is not attenuated by the attenuator 305 and is input to the wireless device 302 via the switch 304 and the distributor 303.

[0074] The grounded cable 320-2 is connected to a grounding point of the battery management device 300. This grounding point coincides with a grounding point of the wireless device 302. In other words, the cable 320-2 is electrically connected to the grounding point of the wireless device 302.

[0075] Fig. 16 shows a modification of the wireless communication system according to the third embodiment of the present invention. Fig. In the modification shown in Fig. 16, the cable 320-1 is connected to the distributor 303 via the switch 304 in the battery management device 300, just like the cable 320 in the modification of the first embodiment.

[0076] Fig. 17 shows an example of a configuration of the terminating resistor 330 according to the third embodiment of the present invention. According to this embodiment, the terminating resistor 330 is formed, for example, by connecting a conductor 321-1 of the cable 320-1 and a conductor 321-2 of the cable 320-2 using a bonding material such as solder to a connecting part 332-1 and a connecting part 332-2 of the printed circuit board 331, respectively, as shown in Fig. 17. The connecting part 332-1 and the connecting part 332-2 are connected to each other via a resistor 333, which is an impedance element. The impedance of the resistor 333 is equal to the input impedance of a transmit signal and the output impedance of a receive signal at the wireless device 302. This suppresses a standing wave in the cable 320-1, allowing it to reliably function as an antenna.

[0077] According to the third embodiment of the present invention described above, the terminating resistor 330 includes two connecting parts 332-1 and 332-2 connected to each other via the resistor 333, which is an impedance element whose impedance is as large as the input impedance of the received signal to the battery management device 300. The connecting part 332-1, which is one of the two connecting parts, is electrically connected to the cable 320-1, while the connecting part 332-2, which is the other of the two connecting parts, is electrically connected to the grounding point of the battery management device 300 via the cable 320-2, which is a grounding cable. Due to this configuration, the cable 320-1 can reliably function as an antenna.

[0078] The embodiments and modifications described above are examples. The present invention can be implemented in other forms as long as the features of the invention are not impaired, and is not limited to these embodiments and modifications. These embodiments and modifications have been described herein, but the present invention is not limited to the contents of the embodiments and modifications. Other modes conceivable within the scope of a technical concept of the present invention are also included within the scope of the present invention. List of reference symbols 1, 1A, 1B wireless communication system 10 battery pack 11 housings 12 Power supply line 100 single battery cells 101 Voltage module 200 Battery data device (slave) 201 Single cell condition measuring device 202 Wireless device 210 Antenna 300 Battery management device (master) 301 Battery monitoring device 302 Wireless device 303 distributors 304 switches 305 Attenuator 310 Antenna 320 cables 321 ladder 322 Insulator 323 Sheathing 330 terminating resistor QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2011-146909 A

[0005]

Claims

[1] A wireless communication system incorporated into a battery pack of a vehicle, the wireless communication system comprising: a battery management device having an antenna and a cable each emitting a first radio signal into the room, the antenna and the cable each outputting a receive signal based on a second radio signal propagating through the room, and a plurality of battery data devices provided in a one-to-one correspondence with a plurality of battery modules included in the battery pack, wherein the battery data devices can wirelessly communicate with the battery management device via the antenna or the cable, wherein the battery management device attenuates or interrupts the received signal from the cable when communicating wirelessly with each of the battery data devices via the antenna. [2] The wireless communication system of claim 1, wherein the cable includes at least one conductor and emits the first radio signal to an area around the conductor based on a current flowing through the conductor. [3] A wireless communication system according to claim 1, wherein the battery management device has a terminating resistor connected to the front end of the cable, wherein the width of the terminating resistor is greater than the arrangement interval of the multiple battery modules in the battery pack and the terminating resistor is arranged in the battery pack in such a way that a connecting part connected to the cable lies between two adjacent battery modules among the plurality of battery modules. [4] The wireless communication system according to claim 3, wherein the terminating resistor comprises a connecting part electrically connected to the cable. [5] A wireless communication system according to claim 3, wherein the terminating resistor comprises two connecting parts connected to each other via an impedance element whose impedance is equal to the input impedance of the received signal in the battery management device, one of the connecting parts is electrically connected to the cable and the other of the connecting parts is electrically connected to an earthing point of the battery management device via an earthing cable. [6] The wireless communication system of claim 5, wherein the cable and the ground wire each comprise a conductor, and the cable emits the first radio signal to the area around the conductor based on a current flowing through the conductor. [7] A wireless communication system incorporated into a battery pack of a vehicle, the wireless communication system comprising: a battery management device having a cable acting as an antenna, and a plurality of battery data devices provided in a one-to-one correspondence with a plurality of battery modules included in the battery pack, wherein the battery data devices wirelessly communicate with the battery management device via the cable.

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