JP2018186637A - System for detecting voltage abnormality of battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a determination unit to determine that a detection module has detected a voltage abnormality of a battery without having to provide a dedicated communication line between the detection module and the determination unit.SOLUTION: A high voltage power source +V produced by increasing a low voltage power source +B from a determination unit 16 is supplied to a high voltage power source line 26. A connection switch 42 is provided between the high voltage power source line 26 and a ground line. A switch control circuit 46 turns on the connection switch 42 upon detecting a voltage abnormality of a battery module 12a. Thus, a current flowing in the high voltage power source line 26 is increased. A current detection part 48 detects a current value flowing in a determination unit inner power source line 22a electrically connected with the high voltage power source line 26. A voltage abnormality determination part 50 determines that a detection module 14 has detected a voltage abnormality of the battery module 12a when a detection value of the current detection part 48 is equal to a current threshold value or greater.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a battery voltage abnormality detection system.

  Conventionally, a battery voltage abnormality detection system that detects a battery voltage abnormality by detecting a voltage value of the battery is known. The battery voltage abnormality may occur, for example, when the battery is overcharged or overdischarged. The battery voltage abnormality detection system may include a detection module that detects battery voltage abnormality and a determination unit that determines a detection result of the detection module. When the determination unit determines that the detection module has detected a battery voltage abnormality, the determination unit or other control unit can perform an appropriate process such as controlling the charge amount or discharge amount of the battery.

  For example, Patent Document 1 discloses a voltage abnormality detection system that detects a voltage of a battery composed of a plurality of assembled batteries, and a satellite substrate as a plurality of detection modules provided for each assembled battery, and a determination A voltage abnormality detection system including a host ECU as a unit is disclosed.

Japanese Patent Laying-Open No. 2015-079585

  Conventionally, in a battery voltage abnormality detection system including a detection module and a determination unit, a dedicated communication line is required for notifying the determination unit of a battery voltage abnormality detected by the detection module. By providing this communication line, there is a problem that a product incorporating the battery voltage abnormality detection system is increased in cost or size. In particular, as in Patent Document 1, for example, when a plurality of detection modules are provided corresponding to a plurality of assembled batteries, a plurality of dedicated communication lines are required, which further increases the cost of the product or increases the size. Become prominent.

  An object of the present invention is to make it possible for the determination unit to determine that the detection module has detected a battery voltage abnormality without providing a dedicated communication line between the detection module and the determination unit.

  The present invention is a battery voltage abnormality detection system including a detection module that detects battery voltage abnormality and a determination unit that determines a detection result of the detection module, and the detection module is supplied from the determination unit. A power line in the detection module for supplying the power to the circuit in the detection module, a connection switch that can be turned on and off provided between the power line in the detection module and the ground line, and a voltage value of the battery A switch control circuit that turns on the connection switch to connect the power line in the detection module and a ground line when the voltage abnormality of the battery is detected, and the determination unit includes the detection unit. Power is supplied to the detection module, which is electrically connected to the power line in the module. A power supply line in the determination unit for supplying a current, a power supply line in the determination unit through which a current supplied to the detection module flows, and a current detection unit that detects a current value of a current flowing in the power supply line in the determination unit; A voltage abnormality determination unit that determines that the detection module has detected the voltage abnormality of the battery when a current value measured by the current detection unit is equal to or greater than a threshold value. This is a voltage abnormality detection system.

  According to the above configuration, when the detection module detects a battery voltage abnormality, the power line in the detection module and the ground line are connected, so the value of the current flowing through the power line in the detection module increases. Since the detection module power supply line and the determination unit power supply line are electrically connected, the current value flowing through the determination unit power supply line increases as the current value flowing through the detection module power supply line increases. Therefore, the voltage abnormality determination unit can determine that the detection module has detected a battery voltage abnormality when the value of the current flowing through the power line in the determination unit detected by the current detection unit is equal to or greater than the threshold value.

  According to the present invention, it is not necessary to provide a dedicated communication line between the detection module and the determination unit, and the determination unit can determine that the detection module has detected a battery voltage abnormality.

1 is a schematic configuration diagram of a battery voltage abnormality detection system according to an embodiment. It is a figure which shows the difference in the electric current value of the electric current which flows through the power supply line in a determination unit at the time of normal time and voltage abnormality detection. It is a graph which shows the timing when the consumption current value of monitoring IC is reduced.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a schematic configuration diagram of a battery voltage abnormality detection system 10 according to the present embodiment. The voltage abnormality detection system 10 in this embodiment is incorporated in a battery pack that is mounted on an electric vehicle such as a hybrid car or an electric vehicle.

  The voltage abnormality detection system 10 includes a battery 12, a detection module 14, and a determination unit 16. In the present embodiment, each of the detection module 14 and the determination unit 16 is an electronic board, and the connector 14a provided in the detection module 14 and the connector 16a provided in the determination unit 16 are connected by the wire material 20, Both are connected. The wire 20 includes only the power line 20a and the ground line 20b.

  The battery 12 is a secondary battery, and is composed of, for example, a lithium ion battery or a nickel metal hydride battery. The battery 12 is configured by connecting a plurality of battery modules 12a each composed of a plurality of single cells (cells) in series. Thereby, the battery 12 can output a voltage of several hundred volts. One battery module 12a can output a voltage of several to several tens of volts. Further, the battery 12 is supplied with electric power from a motor generator mounted on an electric vehicle or electric power from a commercial power source, whereby the battery 12 is charged.

  The detection module 14 detects a voltage abnormality of the battery module 12a (hereinafter simply referred to as “voltage abnormality”). The voltage abnormality means that the voltage value of the battery module 12a is greater than or equal to a predetermined upper limit threshold or less than a predetermined lower limit threshold. In the present embodiment, a plurality of detection modules 14 are provided corresponding to the plurality of battery modules 12a. Each detection module 14 has the same configuration. In addition, as the voltage abnormality detection system 10, the aspect which has only one detection module 14 is also employable.

  The determination unit 16 determines the detection result of the detection module 14. The determination unit 16 is a battery ECU that controls the battery 12, for example. Specifically, the determination unit 16 determines whether any of the plurality of detection modules 14 has detected a voltage abnormality. The determination unit 16 can control charging / discharging of the battery 12 when determining that a voltage abnormality is detected. For example, the discharge amount of the battery 12 or the charge amount to the battery 12 can be limited, or charging of the battery 12 can be started.

  Power for operating the circuits in each detection module 14 is supplied from the determination unit 16. Specifically, the low voltage power source + B (for example, +5 V or +3.3 V, for example) generated in the determination unit 16 or supplied to the determination unit 16 is first provided in the determination unit 16 provided in the determination unit 16. It is supplied to the power supply line 22a. The determination unit power supply line 22 a is a supply path for supplying the low voltage power supply + B to the detection module 14. The determination unit power line 22 a is connected to the low voltage power line 22 b in the detection module 14 by the power line 20 a in the wire 20. As a result, the low-voltage power supply + B is supplied to the low-voltage power supply line 22b. In addition, a current supplied to the detection module 14 flows through the determination unit power line 22a.

  The low voltage power supply + B is supplied to the plurality of detection modules 14. In the present embodiment, the second and subsequent detection modules 14 are connected to the determination unit 16 via other detection modules 14 instead of being directly connected to the determination unit 16, as shown in FIG. The As a result, the low-voltage power supply + B is supplied to the second and subsequent detection modules 14 via the other detection modules 14.

  The low-voltage power supply + B supplied to the low-voltage power supply line 22b is boosted by an insulation power supply circuit 24 (described later) provided in the detection module 14, and the high-voltage power supply + V obtained thereby is within the detection module provided in the detection module 14. It is supplied to a high voltage power line 26 as a power line. The high-voltage power supply line 26 is connected to each circuit in the detection module 14 (in this embodiment, the monitoring IC 40 and the switch control circuit 46), whereby the high-voltage power supply + V is supplied to each circuit in the detection module 14.

  As described above, in this embodiment, the determination unit power line 22a, the power line 20a, the low-voltage power line 22b, and the high-voltage power line 26 are electrically connected to each circuit of the detection module 14. The power is supplied from the determination unit 16 via. The ground line 20b in the wire 20 connects the ground line of the detection module 14 and the ground line of the determination unit 16.

  Hereinafter, the detection module 14 will be described.

  The insulated power circuit 24 includes a low voltage power line 22b, a transformer 28 having a primary coil 28a and a secondary coil 28b, an N-type FET 30, a resistor 32, a control IC 34, a diode 36, a capacitor 38, and a high voltage power line 26. Consists of.

The low-voltage power line 22b is connected to the power terminal of the control IC 34. As a result, the control IC 34 is supplied with the low voltage power source + B. In this embodiment, the current consumption of the control IC 34 is assumed to be negligible compared to a current I ₁ (described later) flowing through the primary coil 28a of the transformer 28. Further, the low voltage power supply line 22 b is connected to one end of the primary coil 28 a of the transformer 28.

  The drain of the N-type FET 30 is connected to the other end of the primary coil 28 a, the source of the N-type FET 30 is connected to one end of the resistor 32, and the gate of the N-type FET 30 is connected to the control terminal of the control IC 34. The other end of the resistor 32 is connected to the ground line.

  One end of the secondary coil 28b of the transformer 28 is connected to the anode of the diode 36, and the other end is connected to the ground line. The cathode of the diode 36 and one end of the capacitor 38 are connected to the high voltage power supply line 26. The other end of the capacitor 38 is connected to the ground line.

In the circuit configuration as described above, when the “H (high)” signal is output from the control terminal of the control IC 34, the N-type FET 30 is turned on. That is, a current flows between the drain and source of the N-type FET 30. As a result, a current I ₁ flows through the primary coil 28 a of the transformer 28. Here, the resistor 32 serves the function of limiting the current I ₁ flowing through the primary coil 28a.

When the current _{I 1} flows through the primary coil 28a, the current _{I 2} flows through the secondary coil 28b by electromagnetic induction. As a result, a high voltage power supply + V is generated on the secondary coil 28b side. The diode 36 exhibits a function of preventing a reverse current flow. The capacitor 38 is a decoupling capacitor and exhibits a function of reducing noise of the high-voltage power supply + V.

It turns _{N 2} turns _{N 1} and the secondary coil 28b of the primary coil 28a, the low-voltage power supply + B and the high voltage source + V, and, following the current _{I 2} flowing in the current _{I 1} and the secondary coil 28b through the primary coil 28a The relationship holds. In this specification, the voltage drop of the diode 36 is not considered.

  Hereinafter, the primary coil 28a side of the transformer 28 is referred to as “low voltage side”, and the secondary coil 28b side is referred to as “high voltage side”. Since the primary coil 28a and the secondary coil 28b are insulated, the low voltage side and the high voltage side are insulated. Note that the low-voltage power supply line 22b and the high-voltage power supply line 26 are insulated, but are electrically connected by a transformer 28.

  The high voltage power supply line 26 is connected to the power supply terminals of the monitoring IC 40 and the switch control circuit 46. As a result, the high voltage power supply + V is supplied to the monitoring IC 40 and the switch control circuit 46. As described above, the high voltage power supply line 26 supplies the power supplied from the determination unit 16 and boosted by the insulated power supply circuit 24 to each circuit of the detection module 14.

  In the present embodiment, the insulated power supply circuit 24 is provided in the detection module 14, but the insulated power supply circuit 24 may be provided in the determination unit 16.

  The monitoring IC 40 detects the voltage value of the battery module 12a. The monitoring IC 40 may also detect the internal resistance value, capacity, temperature, etc. of the battery module 12a. These data detected by the monitoring IC 40 are stored in a memory included in the monitoring IC 40.

  The connection switch 42 is an electronic switch that can be turned on and off. In the present embodiment, the connection switch 42 is a P-type FET. The source of the connection switch 42 is connected to the high-voltage power supply line 26, the drain of the connection switch 42 is connected to one end of the resistor 44, and the gate of the connection switch 42 is connected to a control terminal provided in the switch control circuit 46. The other end of the resistor 44 is connected to the ground line. Thus, the connection switch 42 is provided between the high voltage power supply line 26 and the ground line.

  Similarly to the monitoring IC 40, the switch control circuit 46 detects the voltage value of the battery module 12a. Further, when the voltage value of the battery module 12a is an abnormal value, that is, when a voltage abnormality is detected (hereinafter referred to as “when voltage abnormality is detected”), the switch control circuit 46 reads “from the control terminal of the switch control circuit 46”. L (low) "signal is output. The abnormal value is a value that is greater than or equal to a predetermined upper threshold or less than a predetermined lower threshold. Information indicating the upper and lower thresholds may be stored in advance in a memory included in the switch control circuit 46. When the switch control circuit 46 does not detect a voltage abnormality (hereinafter referred to as “normal time”), an “H” signal is output from the control terminal of the switch control circuit 46.

  In normal times, since the “H” signal is output from the control terminal of the switch control circuit 46, the connection switch 42 is in an OFF state. However, when a voltage abnormality is detected, “L” is output from the control terminal of the switch control circuit 46. The connection switch 42 is turned on. That is, the high voltage power supply line 26 and the ground line are connected via the resistor 44. Thereby, a current flows between the source and drain of the connection switch 42. Here, the resistor 44 functions to adjust the current flowing between the source and drain of the connection switch 42.

  In this embodiment, the switch control circuit 46 performs on / off control of the connection switch 42. However, the monitoring IC 40 can output a signal for performing on / off control of the connection switch 42 (that is, the switch control circuit 46). The monitoring IC 40 may control the connection switch 42 on and off. In this case, the switch control circuit 46 is not necessary.

  Hereinafter, the configuration of the determination unit 16 will be described.

  The current detector 48 detects the current value of the current flowing through the determination unit power line 22a. The current detection unit 48 may be a current sensor or the like. As described above, since the current supplied to each detection module 14 flows through the determination unit power line 22a, the current detection unit 48 detects the current value of the current supplied to each detection module 14. is there. The current value detected by the current detection unit 48 is sent to the voltage abnormality determination unit 50.

  The voltage abnormality determination part 50 is comprised, for example from a microcontroller. The voltage abnormality determination unit 50 determines whether any of the detection modules 14 has detected a voltage abnormality based on the current value detected by the current detection unit 48. Moreover, the voltage abnormality determination part 50 can also control charging / discharging of the battery 12 according to the detection result of the detection module 14. Details of the function of the voltage abnormality determination unit 50 will be described below.

As described above, when the switch control circuit 46 detects a voltage abnormality, the connection switch 42 is turned on. As a result, since the high-voltage power supply line 26 and the ground line are connected, the current flowing through the high-voltage power supply line 26 increases as compared with the normal time. In particular, the value of the current I ₂ flowing through the secondary coil 28b of the transformer 28 increases.

Since the ratio of the number of turns N ₂ turns N ₁ and the secondary coil 28b of the primary coil 28a of the transformer 28 is fixed, as shown in Equation 1, the value of the current I ₂ is increased, the primary along with it current _{I 1} flowing through the coil 28a is also increased. As described above, since the current detection unit 48 detects the current value of the supply current to each detection module 14 including the current I ₁ in each detection module 14, a voltage abnormality is detected in any one of the detection modules 14 and the current is detected. When the value of I ₂ is increased, so that the detected current value of the current detector 48 also increases accordingly. Therefore, the voltage abnormality determination unit 50 can determine that any one of the detection modules 14 has detected a voltage abnormality based on the increase in the detected current value of the current detection unit 48.

  FIG. 2 shows the difference in the detected current value of the current detector 48 between the normal time (the connection switch 42 is off) and the voltage abnormality detection (the connection switch 42 is on). The vertical axis in FIG. 2 indicates the current value flowing through the determination unit power line 22a, that is, the current value detected by the current detector 48. FIG. 2 shows current values that can flow through the determination-unit power line 22a during normal time and when voltage abnormality is detected. In the present embodiment, since the current value flowing through the determination unit power line 22a varies depending on the operating state of each detection module 14, as shown in FIG. 2, the current value that can be taken at the normal time and when the voltage abnormality is detected. Has a certain width.

As described above, the current flowing through the connection switch 42 when voltage abnormality is detected can be adjusted by the resistance value of the resistor 44. That is, it is possible to adjust the value of the current I ₂ during voltage abnormality detection. This means that the value of the current I ₁ at the time of voltage abnormality detection, and thus the current value that can flow through the determination-unit power line 22a, can be adjusted by the resistance value of the resistor 44. The designer of the voltage abnormality detection system, as shown in FIG. 2, has a current value region that is a current value region that can flow through the determination-unit power line 22a in a normal state, and a determination-unit power line 22a when a voltage abnormality is detected The resistance value of the resistor 44 is adjusted so that it does not overlap with the current value region that is the current value region that can flow through the current.

  After adjusting in this way, a current threshold value is set between the upper limit value of the current value region at the normal time and the lower limit value of the current value region at the time of voltage abnormality detection, and information indicating the current threshold value is determined by the determination unit 16. Store in memory. As a result, the voltage abnormality determination unit 50 compares the detected current value detected by the current detection unit 48 with the current threshold value stored in the memory, and if any of the detected current values is greater than or equal to the current threshold value, It can be determined that the module 14 has detected a voltage abnormality.

  As described above, according to the voltage abnormality detection system 10 according to the present embodiment, the determination unit 16 determines that one of the detection modules 14 is detected when the value of the current flowing through the determination-unit power line 22a is equal to or greater than the current threshold. Determines that a voltage abnormality of the battery module 12a has been detected. Therefore, in the voltage abnormality detection system 10, it is not necessary to provide a dedicated communication line for notifying that a voltage abnormality has been detected between each detection module 14 and the determination unit 16. Thereby, the cost increase or enlargement of the battery pack incorporating the voltage abnormality detection system 10 can be prevented.

  In this embodiment, the monitoring IC 40 and the switch control circuit 46 are arranged on the high voltage side, and the microcomputer is arranged on the low voltage side. Therefore, if a dedicated communication line is provided, an insulation circuit for maintaining insulation between the high voltage side and the low voltage side is required in the middle of the communication line. According to the voltage abnormality detection system 10 according to the present embodiment, since a communication line is not necessary, it is not necessary to provide such an insulation circuit for the communication line.

In the present embodiment, in order for the voltage abnormality determination unit 50 to determine that the detection module 14 has detected a voltage abnormality, when the voltage abnormality is detected, a current value larger than the current value of the current I _{2 that} can be normally obtained is detected. it is necessary to flow the current _{I 2.} Therefore, it is necessary for the insulated power supply circuit 24 to be able to pass a current I ₂ having a larger current value than the current I ₂ required during normal operation. That is, it is necessary to increase the suppliable current value of the insulated power supply circuit 24. Thereby, the subject that the insulated power supply circuit 24 raises a cost may arise.

Therefore, in the present embodiment, for example, the current consumption of the monitoring IC 40 is temporarily reduced by temporarily stopping the operation of the monitoring IC 40 or temporarily setting it to the low power consumption mode. In other words, to temporarily reduce the current value of the current I _2. Even in this case, the switch control circuit 46 is always operated. The voltage abnormality determination unit 50 determines whether or not the detection module 14 has detected a voltage abnormality based on the current value detected by the current detection unit 48 when the current consumption of the monitoring IC 40 is reduced. Like that.

  FIG. 3 shows the timing at which the current consumption value of the monitoring IC 40 is reduced. In the graph shown in FIG. 3, the vertical axis indicates the current consumption value of the monitoring IC 40, and the horizontal axis indicates time. In the example of FIG. 3, the current consumption value of the monitoring IC 40 is reduced between time t1 and time t2. That is, the voltage abnormality determination unit 50 determines whether or not the detection module 14 has detected a voltage abnormality based on the current value detected by the current detection unit 48 between time t1 and time t2. In the present embodiment, the current consumption value of the monitoring IC 40 is periodically reduced for a certain period of time, and information indicating the timing at which the current consumption value of the monitoring IC 40 is reduced is stored in advance in the memory in the determination unit 16. Remember. Thereby, the detection module 14 does not need to notify the determination unit 16 that the consumption current value of the monitoring IC 40 has been reduced, and the voltage abnormality determination unit 50 detects the detection module 14 at the timing when the consumption current value of the monitoring IC 40 has been reduced. Can detect whether or not a voltage abnormality is detected.

In this way, in between times t1 to t2, since the current value of the current I ₂ flowing through the normal is reduced, the current value of the current I ₂ which is necessary when a voltage abnormality detection is also reduced. Therefore, the suppliable current value of the insulated power supply circuit 24 can be suppressed, and the cost increase of the insulated power supply circuit 24 can be suppressed.

  As mentioned above, although embodiment which concerns on this invention was described, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the meaning of this invention.

  DESCRIPTION OF SYMBOLS 10 Voltage abnormality detection system, 12 Battery, 12a Battery module, 14 Detection module, 16 Judgment unit, 20 Wire material, 20a Power line, 20b Ground line, 22a Judgment unit power line, 22b Low voltage power line, 24 Insulation power circuit, 26 High voltage power line, 28 transformer, 28a primary coil, 28b secondary coil, 30 N-type FET, 32, 44 resistor, 36 diode, 38 capacitor, 40 monitoring IC, 42 connection switch, 46 switch control circuit, 48 current detection Part, 50 voltage abnormality determination part.

Claims (1)

A battery voltage abnormality detection system including a detection module for detecting battery voltage abnormality and a determination unit for determining a detection result of the detection module,
The detection module includes:
A power line in the detection module for supplying the power supplied from the determination unit to the circuit in the detection module;
An on / off connection switch provided between the power line in the detection module and the ground line;
When the voltage value of the battery is detected and the voltage abnormality of the battery is detected, a switch control circuit that turns on the connection switch and connects the power line in the detection module and the ground line,
With
The determination unit is
A power supply line in the determination unit that is electrically connected to the power supply line in the detection module and that supplies power to the detection module, and a power supply line in the determination unit through which a current supplied to the detection module flows;
A current detection unit for detecting a current value of a current flowing through the power supply line in the determination unit;
A voltage abnormality determination unit that determines that the detection module has detected the voltage abnormality of the battery when the current value measured by the current detection unit is equal to or greater than a threshold;
Comprising
An abnormal voltage detection system for a battery.

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