JP2009103706A - Testing method, testing circuit and battery module of cell voltage sensing line - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide testing method for accurately testing connection status of cell voltage sensing line. <P>SOLUTION: In this method, measure open voltage value of an electric cell (S102), measure voltage value, when the bypass resistance for capacity modulation is connected in parallel with the electric cell to apply current (S106, 116, 126), determine whether difference between the open voltage value and the voltage value is larger than a predefined value (S108, 118, 128), and then determine the connection status of cell voltage sensing lines L1-L4 derived from the electric cell is incorrect, when this difference is the predefined value or larger (steps 112, 122, 132). Thus the use of the voltage value, when resistance is connected in parallel with the electric cell to apply current enables accurate testing of connection status, even if minute disconnections are found on the cell voltage sensing line. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a battery voltage detection line inspection method, an inspection circuit, and a battery module.

  For example, an assembled battery in which a plurality of secondary batteries (hereinafter referred to as single cells) are connected in series corresponding to a required voltage is used for an electric vehicle or the like. Since such an assembled battery uses a plurality of single cells, it is important to ensure reliability. That is, when any of the single cells constituting the assembled battery has its function lowered due to overcharge or overdischarge, the function of the assembled battery as a whole is also lowered. Further, each unit cell constituting the assembled battery has variations at the time of manufacture, and furthermore, the charge acceptance and discharge capacity of each unit cell differ due to the non-uniform temperature distribution. When the assembled battery is used in this state, a unit cell that is overdischarged or overcharged is generated, and the life of the entire assembled battery is shortened.

  For this reason, the battery module is provided with a control circuit that controls each unit cell or battery pack, and detects the voltage of each unit cell by detecting the voltage of each unit cell through a battery voltage detection line derived from the unit cell. The capacity (for example, the product of the current value and time) to be adjusted for each secondary battery according to the battery voltage is calculated by the microcomputer, and the capacity adjustment resistor connected in parallel to the single battery and the capacity adjustment A switch connected in series with the resistor, and a switch of the capacity adjustment circuit composed of a switch is turned on for a predetermined time by calculating a closed circuit between the unit cell and the capacity adjustment circuit, The capacity between cells is adjusted uniformly. The switch of the capacity adjustment circuit is composed of, for example, a unipolar transistor such as an FET or a bipolar transistor, and outputs a high-level signal of binary control from a microcomputer to flow a minute current to the gate or base of the FET or transistor. As a result, a capacitance adjustment current is passed between the drain and source or between the collector and emitter, and the electric power corresponding to the adjustment capacitance is consumed by the resistor.

  By the way, the inspection about the connection state of such a battery voltage detection line conventionally measures the battery voltage for every single cell (for example, refer patent document 1), and the state of a connection state is detected by detecting the voltage of a single cell. The method of confirming was common.

JP 2000-92732 A

  As described above, it is desirable to detect the terminal voltage of each single cell via the battery voltage detection line and to detect the connection state of the battery voltage detection line with high accuracy. That is, it is desirable that the battery voltage detection line can be detected with high accuracy even when the battery voltage detection line is in a minute disconnection state. However, the above-mentioned patent document 1 does not mention detecting the connection state of the battery voltage detection line with high accuracy.

  An object of the present invention is to provide an inspection method, an inspection circuit, and a battery module including the inspection circuit that can inspect the connection state of the battery voltage detection line with high accuracy.

  In order to solve the above-mentioned problem, a first aspect of the present invention is a method for inspecting a battery voltage detection line, wherein a voltage value when a resistor is connected in parallel with a unit cell and a current is passed, and the unit cell When the difference from the open-circuit voltage value is equal to or greater than a predetermined value, it is determined that the connection state of the battery voltage detection line derived from the unit cell is abnormal. In this mode, if there is a minute disconnection in the battery voltage detection line, the voltage value when a current is passed by connecting a resistor in parallel with the cell is higher than when the battery detection line is normal (when there is no minute disconnection). Therefore, it is possible to determine that there is an abnormality in the connection state of the battery voltage detection line because the difference from the open-circuit voltage value of the unit cell is equal to or greater than a predetermined value. In this case, it is preferable to use a capacity adjusting resistor connected in parallel to the unit cell as the resistor.

  In order to solve the above-mentioned problem, the second aspect of the present invention is that each unit cell of an assembled battery constituted by connecting a plurality of unit cells connected in parallel through a switch with a capacity adjustment resistor. An inspection circuit for inspecting a connection state of a derived battery voltage detection line, an open voltage detection means for detecting an open voltage value of the unit cell, a switch control means for controlling on / off of the switch, and the switch Battery voltage detection means for detecting the voltage value of the unit cell in the ON state, and voltage difference calculation means for calculating the difference between the open voltage value and the voltage value detected by the open voltage detection means and the battery voltage detection means And an abnormality determination unit that determines whether or not the difference calculated by the voltage difference calculation unit is equal to or greater than a predetermined value, and determines that the connection state of the battery voltage detection line is abnormal when the difference is equal to or greater than the predetermined value. And comprisingIn this aspect, the open voltage value of the single cell is detected by the open voltage detection means, the switch is turned on by the switch control means, the single battery and the capacity adjusting resistor are connected in parallel, and the switch is turned on by the battery voltage detection means. The voltage value of the unit cell in the state, that is, the voltage value when a current flows when a resistor is connected in parallel with the unit cell is detected. Then, the voltage difference calculating means calculates the open circuit voltage value detected by the open voltage detecting means and the battery voltage detecting means and the difference between the voltage values, and the abnormality calculating means determines the difference calculated by the voltage difference calculating means in advance. It is determined whether or not the battery voltage detection line is greater than or equal to the predetermined value. According to this aspect, if there is a minute disconnection in the battery voltage detection line, the voltage value calculated by the voltage difference calculation means when the resistor is connected in parallel with the unit cell and the current is passed is normal for the battery detection line. Therefore, the abnormality determination means determines that the difference between the open circuit voltage value and the voltage value is greater than or equal to a predetermined value, and determines that the connection state of the battery voltage detection line is abnormal. .

  Furthermore, in order to solve the above-mentioned problem, a third aspect of the present invention is a battery pack configured by connecting a plurality of cells each having a capacity adjustment resistor connected in parallel via a switch, and the cell A battery module including an inspection circuit for inspecting a connection state of the battery voltage detection line derived from the open circuit voltage detecting means for detecting an open voltage value of the unit cell, and the switch. Switch control means for on / off control, battery voltage detection means for detecting the voltage value of the unit cell in the on state of the switch, open voltage value detected by the open voltage detection means and the battery voltage detection means And a voltage difference calculating means for calculating a difference between the voltage values, and determining whether or not the difference calculated by the voltage difference calculating means is equal to or greater than a predetermined value. Wire connection Comprising an abnormality judging means condition is determined to be abnormal, the.

  According to the present invention, the connection state of the battery voltage detection line can be detected with high accuracy.

  Hereinafter, embodiments of a battery module to which the present invention can be applied will be described with reference to the drawings.

(Constitution)
As shown in FIG. 1, the battery module 20 of the present embodiment includes an assembled battery 15 in which three lithium ion secondary batteries (hereinafter referred to as single cells) 1, 7, and 11 are connected in series. The unit cells 1, 7, and 11 are connected in parallel with capacity adjustment circuits 2, 8, and 12, respectively, for adjusting the unit cell capacity.

  That is, one end of capacity adjusting bypass resistors 3, 9, 13 is connected to the + terminals of the cells 1, 7, 11 through battery voltage detection lines L 1, L 2, L 3. , 13 are connected to the drains of FETs 4, 10, 14 functioning as switches, respectively. On the other hand, the sources of the FETs 4, 10, and 14 are connected to the negative terminals of the cells 1, 7, and 11 through battery voltage detection lines L2, L3, and L4, respectively, and the gates of the FETs 4, 10, and 14 will be described later. It is connected to an output port of a microcomputer (hereinafter referred to as a microcomputer) 5. Therefore, when a weak binary high level signal is input from the output port of the microcomputer 5 to the gate of the FET (when turned on), the drain side of the FETs 4, 10, 14 (the + terminal side of the unit cell) to the source side When the current flows through (the −terminal side of the unit cell), the current is thermally consumed by the bypass resistors 3, 9, and 13, and the capacity can be adjusted for each unit cell 1, 7, 11 (hereinafter, FET 4, 10, 14 is referred to as switches 4, 10, and 14 in view of their functions).

  In addition, the battery module 20 controls the open-circuit voltage detection means for measuring the voltage of the single cells 1, 7, and 11 for each single battery, and the voltage measurement circuit 6 as a part of the battery voltage detection means and the battery module 20 to control the open-circuit voltage. Detection means, switch control means, battery voltage detection means, voltage difference calculation means, abnormality determination means, microcomputer 5, charge / discharge of battery pack 15 and rest state are detected and the state of battery pack 15 is output to microcomputer 5 And a power supply unit (not shown) that supplies operating power to the microcomputer 5 and the voltage measurement circuit 6.

  The microcomputer 5 is a CPU that performs arithmetic processing, a ROM that stores programs executed by the CPU and various setting values, a RAM that serves as a work area for the CPU, and an A / D that digitizes an analog voltage from the voltage measurement circuit 6. A conversion unit is included. In addition to the output port that outputs a high level signal to each FET described above, the microcomputer 5 designates the voltage measurement circuit 6 from a single cell designation port for designating a single cell to be measured, and the voltage measurement circuit 6. An AD input port to which the voltage of the single cell is input, and a serial port (not shown) for communicating with a host system that controls the battery module 20 via an interface (I / F).

  The voltage measurement circuit 6 is a circuit that individually measures the voltage of each unit cell, and can be configured by a circuit including a differential amplification circuit having an amplification factor of 1, for example. The input side of the voltage measurement circuit 6 is connected to the battery voltage detection lines L 1, L 2, L 3 and L 4, and the output side of the voltage measurement circuit 6 is connected to the AD input port of the microcomputer 5. In addition, the voltage measurement circuit 6 is connected to a single cell designation port of the microcomputer 5 in order to receive designation of a single cell for voltage measurement from the microcomputer 5. Therefore, the microcomputer 5 designates the voltage measurement target cell from the cell designation port to the voltage measurement circuit 6, thereby taking in the voltage of the measurement target cell from the voltage measurement circuit 6 through the AD input port, and By performing A / D conversion, it is possible to acquire (measure) the voltage value of the designated cell.

  The charge / discharge determination unit (not shown) is inserted between the + terminal of the uppermost unit cell 1 and the + external output terminal of the assembled battery 15. The charge / discharge discriminating unit can be configured to detect the direction of current flowing through the assembled battery 15 using, for example, a shunt (shunt) resistor or a Hall element, and the assembled battery 15 can be in any state of charging, discharging, and resting. Whether or not there is is output to the microcomputer 5. Further, the negative terminal of the cell 11 is connected to the negative external output terminal of the battery module 20, and the positive external output terminal and negative external output terminal of the battery module 20 are connected to a charger or a load.

(Operation)
Next, with reference to a flowchart, operation | movement of the battery module 20 of this embodiment is demonstrated. When the microcomputer 5 is turned on in the initial state, various set values stored in the ROM are transferred to the RAM, and a battery voltage detection line inspection routine for inspecting the battery voltage detection lines L1 to L4 can be executed. When a predetermined signal is received from an inspection jig (not shown) or from a host system via the interface, the following battery voltage detection line inspection routine is executed.

  As shown in FIG. 2, in the battery voltage detection line inspection routine, first, in step 102, open voltage values Vb1, Vc1, and Vd1 of the single cells 1, 7, and 11 are acquired (measured) and stored in the RAM. That is, after specifying the unit cell 1 to be voltage measured from the unit cell designation port to the voltage measurement circuit 6 and acquiring the open voltage value Vb1 and storing it in the RAM, the unit cell 7 is specified and the open circuit voltage value Vc1 is acquired. Similarly, the unit cell 11 is designated and the open-circuit voltage value Vd1 is acquired and stored in the RAM.

  Next, in step 104, the switch 4 is turned on (hereinafter abbreviated as ON), and the switches 10 and 14 are turned off (signals to the gates of the FETs 10 and 14 are at a low level, hereinafter abbreviated as OFF). In the next step 106, the bypass resistor 3 is connected in parallel, and the voltage value Vb2 of the unit cell 1 when the current flows is acquired and stored in the RAM. Next, at step 108, it is determined whether or not the absolute value of (Vb2-Vb1) is smaller than a predetermined value. Such predetermined values include the lengths of the battery voltage detection lines L1 to L4, the joining method of the battery voltage detection lines L1 to L4 and the cells 1, 7, and 11, the values of the bypass resistors 3, 9, and 13 and the like. It is preferable to set an appropriate value in consideration of the influence of (0.8 V in this example). If the determination is affirmative, the fact that there is no abnormality in the battery voltage detection lines L1 and L2 (OK) is stored in the RAM in step 110. If the determination is negative, the battery voltage detection lines L1 and / or L2 are abnormal in step 112. (NG) is stored in the RAM that there is an abnormality (only battery voltage detection line L1 is abnormal, only battery voltage detection line L2 is abnormal, or both battery voltage detection lines L1 and L2 are abnormal).

  Next, in step 114, the switch 10 is turned on, the switches 4 and 14 are turned off, and in the next step 116, the bypass resistor 9 is connected in parallel to obtain the voltage value Vc2 of the unit cell 7 when the current flows. To remember. Next, at step 118, it is determined whether or not the absolute value of (Vc2-Vc1) is smaller than a predetermined value. If the determination is affirmative, the fact that there is no abnormality in the battery voltage detection lines L2 and L3 is stored in the RAM in step 120, and if the determination is negative, there is an abnormality in the battery voltage detection lines L2 and / or L3 in step 122. Is stored in the RAM.

  Next, in step 124, the switch 14 is turned on, the switches 4 and 10 are turned off, and in the next step 126, the bypass resistor 13 is connected in parallel to obtain the voltage value Vd2 of the unit cell 11 when a current is passed. To remember. Next, at step 128, it is determined whether or not the absolute value of (Vd2-Vd1) is smaller than a predetermined value. If the determination is affirmative, the battery voltage detection lines L3 and L4 are stored in the RAM in step 130, and if the determination is negative, the battery voltage detection lines L3 and / or L4 are abnormal in step 132. Is stored in the RAM.

  In the next step 134, it is determined whether or not all the battery voltage detection lines L1 to L4 are abnormal. If the determination is affirmative, the process proceeds to step 168 of FIG. 3, and if the determination is negative, the step of FIG. Go to 136.

  In step 168, since all of the battery voltage detection lines L1 to L4 are not abnormal (OK), a default value representing OK is selected and the process proceeds to step 170. On the other hand, in step 136, the switches 4 and 10 are turned on and the switch 14 is turned off. In the next step 138, the voltage values Vb3 and Vc3 of the single cells 1 and 7 are acquired and stored in the RAM. Next, at step 140, it is determined whether or not the absolute value of {(Vb3 + Vc3) − (Vb1 + Vc1)} is smaller than a predetermined value. If an affirmative decision is made, the fact that there is no abnormality in the battery voltage detection lines L1 and L3 is stored in the RAM in step 142, and if a negative decision is made, there is an abnormality in the battery voltage detection lines L1 and / or L3 in step 144. Is stored in the RAM.

  Next, in step 146, the switches 10 and 14 are turned on and the switch 4 is turned off. In the next step 148, the voltage values Vc4 and Vd3 of the single cells 7 and 11 are acquired and stored in the RAM. Next, at step 150, it is determined whether or not the absolute value of {(Vc4 + Vd3) − (Vc1 + Vd1)} is smaller than a predetermined value. If the determination is affirmative, the fact that there is no abnormality in the battery voltage detection lines L2 and L4 is stored in the RAM in step 152, and if the determination is negative, the battery voltage detection lines L2 and / or L4 are abnormal in step 154. Is stored in the RAM.

  Next, in step 156, the switches 4, 10, and 14 are turned ON, and in the next step 158, the voltage values Vb4, Vc5, and Vd4 of the single cells 1, 7, and 11 are acquired and stored in the RAM. Next, at step 160, it is determined whether or not the absolute value of {(Vb4 + Vc5 + Vd4) − (Vb1 + Vc1 + Vd1)} is smaller than a predetermined value. If an affirmative determination is made, the fact that there is no abnormality in the battery voltage detection lines L1 and L4 is stored in the RAM in step 162, and if a negative determination is made, there is an abnormality in the battery voltage detection lines L1 and / or L4 in step 164. Is stored in the RAM.

  In the next step 166, the battery voltage detection lines L1 to L4 stored in the RAM in steps 142, 144, 152, 154, 162, and 164 are identified as locations where the connection state is abnormal (NG locations), and the identified NG The default value of the location is selected and the process proceeds to step 170. In step 170, the selected default value is output from the interface, and the battery voltage detection line inspection routine is terminated. Thereby, the connection state of the battery voltage detection lines L1 to L4 is displayed on the display of the inspection jig (not shown) or the inspection jig connected to the host system.

(Action etc.)
In the battery module 20 of the present embodiment, by turning ON / OFF the switches 3, 9, and 12, a bypass resistor is connected to a specific unit cell constituting the assembled battery 15 one by one, or combined, The connection state of the battery voltage detection lines L1 to L4 derived from the single cells 1, 7, and 11 can be accurately inspected. That is, if there is a minute disconnection in the battery voltage detection lines L1 to L4, the voltage value when a resistor is connected in parallel with the unit cell and current flows is different from when the battery detection line is not OK. The difference from the open-circuit voltage value of the unit cell is equal to or greater than a predetermined value, and it can be determined for each of the battery voltage detection lines L1 to L4 that the connection state is abnormal. In addition, since the bypass resistors 3, 9, and 13 are connected in parallel to the single cells 1, 7, and 11, without using the resistors outside the battery module 20, these bypass resistors are used to connect the single cells. By measuring the voltage value at the time of discharging, it is possible to inspect the connection state of the battery voltage detection line with higher accuracy. Further, in the battery module 20 of the present embodiment, the battery voltage detection line is stored in the program microcomputer 5 capable of executing the battery voltage detection line inspection routine, and the hardware of the battery voltage detection line is used by using a circuit that the battery module 20 has. Since the connection state is inspected, the burden on the inspection jig (circuit configuration) can be reduced.

  In the present embodiment, an example of software that causes the microcomputer 5 in the battery module 20 to execute the battery voltage detection line inspection routine is shown, but the present invention is not limited to this, and hardware including an OP amplifier and the like You may make it comprise.

  Further, in the present embodiment, an example in which the voltage of the single cell is measured one by one with respect to the voltage measurement circuit 6 is shown, but a voltage measurement circuit that can measure the voltages of a plurality of single cells at a time may be used. .

  Furthermore, in the present embodiment, as shown in FIG. 4, when an abnormality is found in any one of the battery voltage detection lines L1 to L4, the battery voltage detection line that has been found to be normal is reexamined. 3 may be performed only for the battery voltage detection line in which the connection state may be abnormal. In this way, it is possible to quickly identify a battery voltage detection line with an abnormal connection state.

  The present invention provides an inspection method, an inspection circuit, and a battery module including the inspection circuit capable of accurately inspecting the connection state of the battery voltage detection line, and thus has industrial applicability.

It is a block circuit diagram of the battery module of an embodiment to which the present invention is applicable. It is a flowchart of the battery voltage detection line test | inspection routine 1 which CPU of a microcomputer performs. It is a flowchart of the battery voltage detection line test | inspection routine 2 which CPU of a microcomputer performs.

Explanation of symbols

1, 7, 11 Lithium ion secondary battery (single cell)
3, 9, 13 Bypass resistance (resistance, capacity adjustment resistance)
4, 10, 14 FET (switch)
5 Microcomputer (open voltage detection means, switch control means, battery voltage detection means, voltage difference calculation means, abnormality determination means)
15 Battery pack 20 Battery module L1, L2, L3, L4 Battery voltage detection line

Claims (4)

  A battery voltage detection derived from the unit cell when a difference between a voltage value when a resistor is connected in parallel with the unit cell and a current flows and an open voltage value of the unit cell is equal to or greater than a predetermined value. An inspection method for a battery voltage detection line, wherein the connection state of the line is determined to be abnormal.   The battery voltage detection line inspection method according to claim 1, wherein a capacity adjustment resistor connected in parallel to the single cell is used as the resistor. An inspection circuit for inspecting a connection state of a battery voltage detection line derived from each unit cell of an assembled battery configured by connecting a plurality of unit cells connected in parallel via a switch with a capacity adjustment resistor,
An open-circuit voltage detecting means for detecting an open-circuit voltage value of the unit cell;
Switch control means for controlling on and off of the switch;
Battery voltage detection means for detecting a voltage value of the unit cell in the ON state of the switch;
A voltage difference calculation means for calculating an open voltage value detected by the open voltage detection means and the battery voltage detection means and a difference between the voltage values;
Determining whether or not the difference calculated by the voltage difference calculation means is greater than or equal to a predetermined value, and determining whether or not the connection state of the battery voltage detection line is abnormal when the difference is greater than or equal to a predetermined value;
A detection circuit comprising: An assembled battery configured by connecting a plurality of cells connected in parallel via a switch with capacity adjusting resistors, and an inspection circuit for inspecting a connection state of a battery voltage detection line derived from the cells. A battery module, wherein the inspection circuit comprises:
An open-circuit voltage detecting means for detecting an open-circuit voltage value of the unit cell;
Switch control means for controlling on and off of the switch;
Battery voltage detection means for detecting a voltage value of the unit cell in the ON state of the switch;
A voltage difference calculation means for calculating an open voltage value detected by the open voltage detection means and the battery voltage detection means and a difference between the voltage values;
Determining whether or not the difference calculated by the voltage difference calculation means is greater than or equal to a predetermined value, and determining whether or not the connection state of the battery voltage detection line is abnormal when the difference is greater than or equal to a predetermined value;
Battery module with

Images