JP2009250615A - Voltage measuring device and electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a voltage measuring device which is capable of acquiring voltage information on at least some one of battery blocks even if a fault occurs in any of voltage measuring units. <P>SOLUTION: A voltage measuring part 22 is a group of voltage detecting parts which are connected in parallel with battery blocks constituting a combination battery and detect the inter-terminal voltage of the battery blocks and which are provided respectively for each battery block. The voltage measuring part is equipped with the voltage detecting parts 24 which are connected in series through relay signal lines different from each other, as to each of at least two groups divided beforehand based on the temperature characteristic of each voltage block, and relay the voltage information showing the inter-terminal voltage of the battery block, in sequence on a serial basis, through the relay signal line of each group, and with a voltage information collecting part 26 which collects, for each group, the voltage information that each voltage detecting part 24 relays on the serial basis through each relay signal line in each group. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a voltage measuring device for measuring a voltage between terminals of each battery block constituting an assembled battery.

  In a vehicle including a secondary battery including a plurality of battery blocks as a power source, an electrical state of each battery block is measured, and charging / discharging of the secondary battery is controlled based on the state. Are known.

  For example, in Patent Documents 1-3, a voltage detection unit is provided for each battery block, each voltage detection unit is connected in series to form one transmission path, and between each terminal detected by each voltage detection unit A voltage measuring device that transmits information indicating voltage (hereinafter referred to as “voltage information”) in a serial manner through the transmission path, and measures the voltage between terminals of the battery block in response to input of the transmitted voltage information. It is disclosed.

  Patent Document 4 discloses a system including a cell monitoring IC chip that monitors the voltage of a battery cell, a control IC chip that controls the battery cell, and a main controller that transmits and receives signals via the control IC and insulation. Yes. The cell monitoring IC chip monitors the abnormality of the control IC chip or the abnormality of the battery cell connected to the control IC by the first signal output from the main controller via the first insulation. When the abnormality is detected, the cell monitoring IC chip specifies the control IC chip by the second signal output from the main controller via the second insulation. Alternatively, the cell IC chip searches for abnormal contents of the control IC chip or the battery cell connected to the control IC by the second signal.

Japanese Patent Laid-Open No. 9-139237 JP 2003-70179 A JP 2006-29895 A JP 2005-318750 A

  By the way, as described above, when voltage information detected by each voltage detection means connected in series is serially transmitted through one transmission path, if any abnormality occurs in any voltage detection means or signal line. The transmission path is interrupted, and all voltage information may not be transmitted.

  In order to prevent voltage information from being transmitted even if an abnormality occurs in any of the voltage detection means, it is conceivable to duplicate each voltage detection means. However, duplication of each voltage detection means generally causes an increase in cost.

  On the other hand, for example, when controlling the charging / discharging of the secondary battery using the voltage information of each battery block as a parameter, the voltage information of several battery blocks is used even if the voltage information of all the battery blocks cannot be obtained. In some cases, it may be preferable to design the battery so that charging / discharging of the secondary battery can be controlled temporarily.

  The present invention provides a voltage measuring device that connects voltage detection units provided for each battery block in series to construct a relay path, and acquires voltage information detected by each voltage detection unit via the relay path. It is an object of the present invention to provide a voltage measuring device that can acquire voltage information of at least one battery block even if any voltage detection unit has a problem.

  The voltage measuring device according to the present invention is a voltage detection unit group that is connected to each battery block constituting the assembled battery and detects a voltage between terminals of the battery block, and is based on a temperature characteristic of each battery block in advance. Voltage that is connected in series via different relay signal lines for each of at least two assigned groups, and sequentially relays voltage information indicating the voltage between the terminals of the battery block via the relay signal lines of each group in a serial manner. And a voltage information collection unit that collects voltage information relayed by the voltage detection unit group in a serial manner via each relay signal line for each group.

  In one aspect of the voltage measuring device according to the present invention, the assembled battery is configured by stacking the battery blocks, and measures a voltage between terminals of each battery block disposed at both ends in the stacking direction. Each voltage detection part belongs to a mutually different group, It is characterized by the above-mentioned.

  In one aspect of the voltage measuring apparatus according to the present invention, the assembled battery is configured by stacking the battery blocks, and each voltage detection unit calculates a voltage between terminals of battery blocks adjacent to each other in the stacking direction. It belongs to the group different from the voltage detection part to detect.

  In one aspect of the voltage measuring apparatus according to the present invention, the assembled battery is configured by stacking the battery blocks, and the at least two groups correspond to the odd-numbered battery blocks in the stacking direction. A group to which the detection unit belongs and a group to which each voltage detection unit corresponding to an even-numbered battery block in the stacking direction belongs.

  The electric vehicle according to the present invention includes the voltage measuring device, and a control unit that controls charging / discharging of the assembled battery based on voltage information of at least one battery block measured by the voltage measuring device, An assembled battery is used as a drive source. This avoids the risk of acquiring biased voltage information in the assembled battery.

  According to the present invention, the voltage information collection unit sequentially collects voltage information indicating the voltage between the terminals of the battery block for each of at least two groups allocated in advance based on the temperature characteristics of each battery block. Even if a failure occurs in any one of the voltage detection units belonging to any group and the voltage information collecting unit cannot collect the voltage information, it has a temperature characteristic similar to the temperature characteristic of any one of the groups. Voltage information can be collected from each voltage detector of another group to which the battery block belongs.

  The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an electric vehicle (PEV) equipped with a secondary battery that supplies electric power to a drive source. In this embodiment, an electric vehicle (PEV) will be described as an example. However, if the system measures the battery voltage of a secondary battery, a hybrid electric vehicle (HEV) having an engine and a secondary battery, a fuel cell, and a battery The present invention can also be applied to an electric vehicle such as a hybrid vehicle having a secondary battery.

  The electric vehicle includes a secondary battery 10, a battery electronic control unit (hereinafter referred to as a battery ECU) 20, a relay 30, an inverter 40, a motor generator 50, and a vehicle electronic control unit (hereinafter referred to as a vehicle ECU) 60.

  The battery ECU 20 includes a voltage measurement unit 22 (voltage measurement device) therein, and measures the battery voltage V of the secondary battery 10. Further, the battery ECU 20 calculates the state of charge of the secondary battery 10 (hereinafter referred to as SOC (State Of Charge)) based on information such as the battery voltage V, the charge / discharge current I, and the battery temperature T. Transmits battery information such as the SOC and battery temperature of the secondary battery 10 to the vehicle ECU 60. Further, the battery ECU 20 controls the opening and closing of the switch element of the relay 30 based on the battery voltage V. The charging / discharging of the secondary battery 10 is controlled by controlling the inverter 40 based on the battery information.

  The electric vehicle configured as described above runs under the control of the battery ECU 20 and the vehicle ECU 60 by converting DC power from the secondary battery 10 into AC power via the inverter 40 and driving the motor generator 50.

  FIG. 2 is a diagram mainly showing a voltage measurement unit 22 used for measuring the battery voltage of the secondary battery 10 among the functional blocks provided in the battery ECU 20.

  In FIG. 2, the secondary battery 10 is configured by electrically connecting six battery blocks B <b> 1 to B <b> 6 (hereinafter simply referred to as “battery block B” when collectively referring to each battery block). Assembled battery. Each of the battery blocks B is configured by electrically connecting two battery modules in series, and each battery module is configured by electrically connecting six unit cells in series. As each single battery, a nickel metal hydride battery, a lithium ion battery, or the like can be used. In addition, the number of battery blocks, battery modules, and single cells is not particularly limited. The configuration of the secondary battery is not limited to the above example. In addition, the unit cell is not limited to a specific shape such as a square shape or a cylindrical shape.

  The voltage measurement unit 22 includes voltage detection units 24-1 to 24-6 (hereinafter referred to as “voltage detection unit 24” when collectively referred to as each voltage detection unit) provided for each battery block, and each voltage detection unit. And a voltage information collecting unit 26 that collects voltage information indicating the inter-terminal voltage measured by the unit 24.

  The voltage information collection unit 26 forms a closed circuit (loop circuit) with the voltage detection unit 24 through a signal line, and sequentially displays voltage information indicating the voltage across the terminals of the battery block B detected by the voltage detection unit 24 in a serial manner. get.

  In the present embodiment, the battery block B is divided into two groups, and the voltage information collection unit 26 forms a closed circuit with each voltage detection unit 24 for each group, and sequentially acquires voltage information for each group in a serial manner.

  In the present embodiment, grouping is performed so that at least one battery block B having similar temperature characteristics belongs to different groups.

  More specifically, the battery blocks having similar surface temperature characteristics of the battery blocks B are grouped so as to belong to different groups. In many cases, a secondary battery mounted on an electric vehicle such as an electric vehicle is stacked with battery blocks adjacent to each other. In the present embodiment, the two-dimensional or three-dimensional arrangement in the direction perpendicular to the length direction of the battery module is referred to as a stacked arrangement. When arranged in this way, the battery blocks on both ends in the stacking direction have a large heat dissipation surface, and thus easily radiate heat. On the other hand, the battery block near the center in the stacking direction has a narrow heat radiating surface and is unlikely to radiate heat. When charging / discharging is continued in such a state, the temperature of the battery block near the center in the stacking direction rises more than the battery blocks on both ends. Generally, a secondary battery is more likely to deteriorate at a high temperature, and a difference in battery characteristics is likely to occur between the battery block near the center and the battery blocks on both ends. Therefore, for example, the battery blocks on both ends in the stacking direction are grouped so as to belong to different groups. In addition, the battery blocks are distributed alternately in the stacking direction to perform grouping. By grouping in this way, battery blocks having similar temperature characteristics are distributed to different groups, and the risk of acquiring biased voltage information in the assembled battery can be avoided.

  According to the present embodiment, at least one battery block having similar temperature characteristics is divided into separate groups, so that the voltage information collecting unit 26 detects the battery block detected by the voltage detection unit 24 for each group. Voltage information can be collected. Therefore, for example, even if a failure occurs in any one of the voltage detection units 24 belonging to one group and the voltage information collection unit 26 cannot collect voltage information, it is similar to the temperature characteristics of the one group. Voltage information can be collected from each voltage detection unit 24 of the other group to which the battery block having temperature characteristics belongs. Therefore, for example, even if the voltage information collection unit 26 cannot collect voltage information from one of the groups, the battery ECU 20 can obtain the voltage information of the other group to which the battery block having at least similar temperature characteristics belongs. It can be used to temporarily control charging / discharging of the secondary battery.

  In the present embodiment, an example in which each battery block is divided into two groups will be described. However, as long as battery blocks having similar temperature characteristics are distributed to different groups, the groups to be distributed may be distributed to three or more groups.

  Here, the circuit configuration of the voltage detection unit 24 and the voltage information collection unit 26 will be further described with reference to FIG. The two groups to which the battery blocks are distributed based on the temperature characteristics are referred to as “group 1” and “group 2”, respectively.

  The voltage information collection unit 26 outputs a command signal for the voltage detection units 24-1, 24-3, 24-5 (hereinafter collectively referred to as “first voltage detection unit group”) belonging to the group 1. To output command signals to the first output signal line So1 and the voltage detection units 24-2, 24-4, and 24-6 (hereinafter collectively referred to as “second voltage detection unit group”) belonging to the group 2. Are connected to the second output signal line So2. In addition, the voltage information collection unit 26 receives a first input signal line Si1 for receiving a response signal input to the command signal from the first voltage detection unit group, and a response signal input to the command signal from the second voltage detection unit group. A second input signal line Si2 for receiving is connected.

  Each voltage detection part 24 is connected to the positive electrode side terminal and the negative electrode side terminal of each battery block B, and measures the voltage between terminals.

  The first voltage detection unit groups are connected in series with each other via the first relay signal line Sb1, and the voltage detection unit 24-1 on the highest potential side (frontmost stage side) in the group 1 is the first output signal line. The voltage information collection unit 26 is connected via So1. Further, the voltage detection unit 24-5 on the lowest potential side (last stage side) in the group 1 is connected to the voltage information collection unit 26 via the first input signal line Si1.

  On the other hand, the second voltage detection unit group is connected in series with each other via the second relay signal line Sb2, and the voltage detection unit 24-2 on the highest potential side in the group 2 is connected with the second output signal line So2. The voltage information collecting unit 26 is connected. Further, the voltage detection unit 24-6 on the lowest potential side in the group 2 is connected to the voltage information collection unit 26 via the second input signal line Si2.

  That is, the voltage information collection unit 26 and the first detection unit group are connected in series (in a ring shape) via the signal lines So1, Sb1, and Si1, and constitute one closed circuit (loop circuit). In addition, the voltage information collection unit 26 and the second detection unit group are connected in series via the signal lines So2, Sb2, and Si2 to form one closed circuit.

  The voltage information collection unit 26 acquires voltage information of each battery block B from each voltage detection unit via the signal lines So1, Sb1, Si1 or the signal lines So2, Sb2, Si2 for each group. Hereinafter, a procedure in which the voltage information collection unit 26 collects voltage information from the voltage detection units 24-1, 24-3, and 24-5 belonging to the group 1 will be described. The voltage detection units 24-2, 24-4, and 24-6 belonging to the group 2 may be performed in the same procedure.

  That is, the voltage information collection unit 26 outputs a start signal to the voltage detection unit 24-1 on the highest potential side in the group 1 via the first output signal line So1. The voltage detection unit 24-1 receives an activation signal and starts measuring the voltage across the terminals of the battery block B, and the voltage detection unit is connected to the activation signal at a lower potential side (rear stage side) than itself. 24-3 is output via the first relay signal line Sb1-1. The voltage detector 24-1 temporarily holds the measured voltage across the terminals of the battery block B in its own memory.

  When the voltage detection unit 24-3 receives an activation signal input via the first relay signal line Sb1-1, the voltage detection unit 24-3 performs the same operation as the voltage detection unit 24-1. As described above, each voltage detection unit 24 receives the activation signal from the higher potential side of itself, measures the terminal voltage of the battery block B, and transfers the activation signal to the lower potential side of itself.

  When the voltage detection unit 24-5 on the lowest potential side in the group 1 receives the activation signal, the voltage detection unit 24-5 transfers the activation signal to the voltage information collection unit 26 via the first input signal line Si1.

  The voltage information collection unit 26 outputs a start signal to the voltage detection unit 24-1 on the highest potential side of the group 1 via the first output signal line So1, and then the voltage detection unit 24-5 on the lowest potential side of the group 1 After waiting for the activation signal to be transferred from, the voltage request signal is output to the highest potential side voltage detector 24-1 via the first signal line So1 in a serial manner.

  The voltage detection unit 24-1 receives the input of the voltage request signal, adds the voltage information between the terminals measured by itself to the voltage request signal, and performs a first relay to the voltage detection unit 24-3 on the low potential side in a serial manner. The signal is output via the signal line Sb1.

  When receiving the input of the voltage request signal, the voltage detector 24-3 performs the same operation as the voltage detector 24-1. In this way, each voltage detection unit 24 receives a voltage request signal from the higher potential side than itself, adds the voltage information obtained by measuring itself to the voltage request signal, and sends a voltage request to the lower potential side in a serial manner. Transfer the signal.

  When the voltage information collection unit 26 receives a voltage request signal input in a serial manner from the voltage detection unit 24-5 on the lowest potential side, the voltage information collection unit 26 checks whether the voltage request signal is normal by a parity check or the like.

  With this configuration, the voltage information is transmitted from the high voltage side voltage detection unit 24 of each group to the low voltage side voltage detection unit 24 of each group, and the transmitted voltage information is the voltage information collection unit 26. It is aggregated with.

  As described above, in this embodiment, the voltage information collection unit 26 sorts battery blocks having similar temperature characteristics into different groups, and collects voltage information of the battery blocks for each group. Therefore, even if the voltage information of any group cannot be collected, the battery ECU 20 tentatively controls charging / discharging of the secondary battery 10 based on the voltage information of the group whose temperature characteristics are similar to that group. can do.

  In the above embodiment, the example in which the voltage detection units are alternately distributed in the stacking direction of the battery blocks has been described. That is, in the above-described embodiment, an example has been described in which each voltage detection unit corresponding to an odd-numbered battery block in the stacking direction and each voltage detection unit corresponding to an even-numbered battery block in the stacking direction are grouped. However, grouping is not limited to the above example. For example, as shown in FIG. 3, the battery block may be divided into two groups, a group on one end side and a group on the other end side from the approximate center in the stacking direction, and voltage information may be collected for each group. .

  In the above embodiment, the grouping is performed in consideration of the arrangement of the battery blocks. For example, in addition to the arrangement of the battery blocks, the members are arranged around the battery blocks and affect the temperature characteristics of the battery blocks. Grouping may be performed in consideration of the above. For example, in the case of a secondary battery mounted on a vehicle equipped with an engine (internal combustion engine), an exhaust pipe may be disposed at the bottom of the secondary battery. The exhaust pipe radiates heat because high-temperature exhaust gas discharged from the engine passes through it. Therefore, when a part of the battery block constituting the secondary battery is disposed in the vicinity of the exhaust pipe, the battery block disposed in the vicinity is less radiated than the other battery blocks. Therefore, the battery blocks arranged in the vicinity of the exhaust pipe may be allocated to different groups.

  In the above embodiment, the voltage information is transmitted from the high voltage side voltage detection unit 24 of each group to the low potential side voltage detection unit 24 of each group. However, the voltage information is transmitted from the low potential side to the high potential side. May be.

It is a figure which shows schematic structure of the electric vehicle carrying the secondary battery which supplies electric power to a drive source. It is the figure which showed centering on the voltage measurement part used in order to measure the battery voltage of a secondary battery among the functional blocks with which the inside of battery ECU is equipped. It is a figure which shows the modification of the voltage measurement part which concerns on this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Secondary battery, 20 Battery ECU, 22 Voltage measurement part, 24 Voltage detection part, 26 Voltage information collection part, 30 Relay, 40 Inverter, 50 Motor generator, 60 Vehicle ECU.

Claims (5)

A group of voltage detectors that are arranged in parallel for each battery block constituting the assembled battery and detect the voltage across the terminals of the battery block, and each of at least two groups allocated in advance based on the temperature characteristics of each battery block A voltage detection unit group connected in series via different relay signal lines, and sequentially relaying voltage information indicating the voltage between terminals of the battery block via the relay signal lines of each group in a serial manner;
A voltage information collecting unit that collects voltage information relayed in a serial manner by the voltage detection unit group for each group via each relay signal line; and
A voltage measuring device comprising: The voltage measurement device according to claim 1,
The assembled battery is configured by stacking the battery blocks,
Each voltage detector that measures the voltage between terminals of each battery block disposed at least at both ends in the stacking direction belongs to a different group.
A voltage measuring device characterized by that. The voltage measurement device according to claim 1,
The assembled battery is configured by stacking the battery blocks,
Each voltage detection unit belongs to a group different from the voltage detection unit that detects the voltage between the terminals of the battery blocks adjacent to each other in the stacking direction,
A voltage measuring device characterized by that. The voltage measurement device according to claim 1,
The assembled battery is configured by stacking the battery blocks,
The at least two groups are a group to which each voltage detection unit corresponding to an odd-numbered battery block in the stacking direction belongs, and a group to which each voltage detection unit corresponding to an even-numbered battery block in the stacking direction belongs.
A voltage measuring device characterized by that. A voltage measuring device according to any one of claims 1 to 4,
Control means for controlling charging / discharging of the assembled battery based on voltage information of at least one battery block measured by the voltage measuring device;
An electric vehicle using the assembled battery as a drive source.

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