JP4874034B2 - Battery pack for electric vehicles - Google Patents

Description

The present invention detects a leakage of the battery pack to be mounted in an electric vehicle, in a state of being connected to a load, comprising a leakage detection circuit for determining whether leakage is in one of the battery set side and the load side The present invention relates to an assembled battery for an electric vehicle .

Since the assembled battery for an electric vehicle outputs a direct current having a high voltage, it is possible to reliably detect a leakage and effectively prevent harmful effects such as an electric shock. A method for detecting leakage of an assembled battery has been developed as shown in Patent Document 1 filed by the present applicant. (See Patent Document 1)
JP 2005-338010 A

The leakage detection method described in Patent Document 1 includes a leakage detection resistor R _a connected in series to two battery terminals on any high voltage side and low voltage side of a battery set in which a plurality of batteries are connected in series _. R _b is connected to each other _, and leakage detection switches SW _{1 and} SW ₂ are connected between the respective leakage detection resistors R _{a and} R _b , and one leakage detection switch SW ₁ is closed at the timing t _1. open the other leakage detection switch SW _2, the voltage _V l11 occurring leakage detection resistance _{R a} connected to the leakage detection switch SW ₁ a _{(t 1)} was measured, also open the SW ₁ at timing _{t 2,} SW ₂ to close, to measure the voltage _V l12 _{(t 2)} generated in the leakage detection resistance _{R a} connected to the leakage detection switch SW _2. Furthermore, the voltages V _g11 (t ₁ ) and V _g12 (t ₂ ) of _two battery terminals on the high voltage side and the low voltage side, which are parts where these leakage detection resistances _Ra are connected, are measured, and the leakage resistance is measured. _Is calculated based on the following equation.

  This leakage detection method can correctly detect the leakage of the assembled battery regardless of the leakage from any location. However, this leakage detection method has a drawback that it cannot be determined whether the leakage is on the load side or the battery assembly side. It is necessary to correctly detect the point of occurrence of electric leakage in order to identify the failure point and improve safety in the event of a failure.

  The present invention has been developed for the purpose of solving this drawback. An important object of the present invention is to provide an assembled battery leakage detection method for an electric vehicle that can accurately determine whether the leakage is on the battery assembly side or the load side and improve safety.

An assembled battery for an electric vehicle according to the present invention has the following configuration in order to achieve the above-described object.
A battery set formed by connecting a plurality of batteries, and an arbitrary battery terminal at two locations on the high voltage side and the low voltage side of the battery set and the ground, and the battery terminal on the high voltage side A leakage detection circuit in which a leakage detection resistor and a leakage detection switch are arranged in series between the ground and the battery terminal on the low voltage side and the ground, and a load is connected to the output side via a contactor. In the connected battery pack for an electric vehicle, the leakage detection switch on the high voltage side and the leakage detection switch on the low voltage side are configured to be openable and closable at individual timings, and the leakage detection circuit includes the leakage detection resistor A leakage detector that calculates a leakage resistance by using a voltage detection means for detecting a voltage of the leakage detection resistance and a voltage of the leakage detection resistance detected by the voltage detection means for a plurality of states in which the leakage detection switch is controlled to be turned on and off. And an arithmetic unit, the leakage calculation unit, said contactor calculates a leakage resistance of the battery set side while switching off the, leak resistance and the load side of the battery set side in a state of switched on the contactor And the leakage resistance on the load side is calculated from the combined resistance and the leakage resistance on the battery assembly side, and a preset resistance is set in advance, and the set resistance and each leakage resistance are When the leakage resistance on the battery set side is smaller than the set resistance, it is determined that the leakage is on the battery set side, and when the leakage resistance on the load side is smaller than the set resistance, the load side It is configured to determine an electrical leakage .

  The leakage detection method of the present invention can improve safety by accurately determining leakage on the battery assembly side and the load side. This is because the contactor connected to the output side of the battery group is switched off and the load is disconnected, the leakage on the battery group side is detected, and the contactor is switched on and the load is connected in parallel to each other. This is because the leakage resistance on the load side and the battery assembly side connected to the battery is detected. According to the leakage detection method of the present invention that can accurately detect the leakage on the load side and the battery assembly side, maintenance can be performed efficiently and safely with the assembled battery mounted on the vehicle. This is because the leakage portion can be clarified because the leakage portion is specified. The assembled battery mounted in the vehicle is connected to a vehicle load, that is, a converter that converts direct current into alternating current and supplies the motor to a motor via a long lead wire connected to the output side. The lead wire is connected to the converter via an output connector or the like. Even if leakage of the assembled battery is detected, if it is not possible to determine whether the leakage location is on the battery assembly side or on the load side of the vehicle, it is extremely troublesome to specify the leakage site, and maintenance becomes difficult. The leakage detection method of the present invention is a simple method for switching the contactor on and off, and can determine whether the leakage portion is on the battery assembly side or the load side, so that the leakage can be repaired easily and efficiently.

  Embodiments of the present invention will be described below with reference to the drawings. However, the following embodiment exemplifies a method for detecting a leakage of an assembled battery for an electric vehicle for embodying the technical idea of the present invention, and the present invention specifies the leakage detection method as the following method. do not do.

  Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  FIG. 1 shows a circuit diagram in which an assembled battery 1 for an electric vehicle is mounted on a vehicle. In this circuit diagram, an assembled battery 1 for an electric vehicle has a load 2 connected to an output side of a battery set 9 formed by connecting a plurality of batteries 10 in series via a contactor 3. The load 2 is a converter 4 in which a large capacity capacitor is connected in parallel. The converter 4 converts the high-voltage direct current supplied from the battery set 9 into a three-phase alternating current, boosts the voltage if necessary, and supplies it to the motor 5 that runs the vehicle.

  The contactor 3 is switched on and off by the control circuit 6. The contactor 3 switches on the ignition switch and is switched on when the vehicle is running, and outputs a direct current from the assembled battery 1 to the converter 4. When the ignition switch is switched off or when necessary, the contactor 3 is switched off to cut off the output of the assembled battery 1.

The leakage of the assembled battery 1 and the load 2 is detected as follows in the flowchart shown in FIG.
[Step of n = 1]
It is determined whether the contactor 3 is on or off.
[Step of n = 2]
When the contactor 3 is switched off, the load 2 is disconnected, so that the leakage resistance R1 on the battery assembly side is detected.
[Step n = 3]
When the contactor 3 is switched on, the assembled battery 1 and the load 2 are connected, so that the leakage resistance R1 on the battery assembly side and the leakage resistance R2 on the load side are connected in parallel. Therefore, in this state, the combined resistance Rt of the leakage resistance R1 on the battery set side and the leakage resistance R2 on the load side is detected.
[Steps n = 4, 5]
It is determined whether the leakage resistance R1 on the battery assembly side, the combined resistance Rt of the leakage resistance R1 on the battery assembly side and the leakage resistance R2 on the load side is detected, and the leakage resistance R1 and the combined resistance Rt are detected. Then, the leakage resistance R2 on the load side is calculated from the leakage resistance R1 and the combined resistance Rt.

The leakage resistance R2 is calculated by the following equation.
R2 = Rt * R1 / (R1-Rt)

  When the leakage resistance R1 is smaller than the set resistance, it is determined that the leakage is on the battery group side. On the other hand, if the leakage resistance R2 is smaller than the set resistance, it is determined that the load is leaking.

  As described in Japanese Patent Application Laid-Open No. 2005-338010 filed by the present applicant, the leakage resistance R1 and the combined resistance Rt are detected by the following method. In this detection method, the leakage resistance Rl is detected by the leakage detection circuit 11 shown in FIG.

  The leakage detection circuit 11 shown in FIG. 1 is a leakage detection circuit for detecting leakage of the assembled battery 1 for an electric vehicle, and includes an arbitrary high voltage side of the battery set 9 in which a plurality of batteries 10 are connected in series. The leakage detection resistors Ra and Rb connected in series between the battery terminals A and B at two locations on the low voltage side and the ground, the voltage at the battery terminal A on the high voltage side, and the battery on the low voltage side, respectively. Based on the voltage detection means 12 for measuring the voltage at the terminal B, the voltage detection circuits 13 and 14 for detecting the voltage generated in the leakage detection resistor Ra, and the measured values of the voltage detection means 12 and the voltage detection circuits 13 and 14 A leakage calculation unit 15 for calculating the leakage resistance Rl.

  The earth leakage detection resistors Ra and Rb are connected between arbitrary battery terminals A and B on the high voltage side and the low voltage side of the plurality of batteries 10 connected in series with each other and the ground. Electric leakage detection switch SW1 is connected in series to electric detection resistors Ra and Rb connected to the high voltage side, and electric leakage detection switch SW2 is connected in series to electric detection resistors Ra and Rb connected to the low voltage side. is doing. Here, the battery terminals A and B may be both terminals of the battery set. The resistance values of the leakage detection resistors Ra and Rb connected to the points A and B are the same, respectively, and the leakage detection switches SW1 and SW2 can be opened and closed at individual timings.

  The voltage detection means 12 measures the voltage at the battery terminal A on the high voltage side as Vg11 (t) and the voltage at the battery terminal B on the low voltage side as Vg12 (t) at time t.

  At time t, the voltage detection circuit 13 closes one leakage detection switch SW1 and opens the other leakage detection switch SW2. The voltage generated in the leakage detection resistor Ra on the high voltage side is Vl11 (t). Detect as. The voltage detection circuit 14 outputs the voltage generated in the leakage detection resistor Ra on the low voltage side in the state where one leakage detection switch SW1 is opened and the other leakage detection switch SW2 is closed at the timing of time t. Detect as.

  The earth leakage calculation unit 15 calculates the earth leakage resistance Rl based on the following equation 2 when different times t are t1 and t2. That is, at the timing t1, the voltage Vg11 (t1) at the battery terminal A on the high voltage side and the voltage Vg12 (t1) at the battery terminal B on the low voltage side are measured, and the leakage detection switch SW1 is closed to detect the leakage. The switch SW2 is opened to measure the voltage Vl11 (t1) generated in the leakage detection resistor Ra connected to the leakage detection switch SW1, and at the timing t2, the voltage Vg11 (t2) at the battery terminal A on the high voltage side is measured. The voltage at the battery terminal B on the low voltage side is measured as Vg12 (t2), and the leakage detection switch SW1 is opened and the leakage detection switch SW2 is closed, and is generated in the leakage detection resistor Ra connected to the leakage detection switch SW2. The voltage Vl12 (t2) is measured, and the leakage resistance Rl is calculated based on the following equation.

  The leakage detection circuit 11 detects the leakage resistance R1 on the battery assembly side in a state where the contactor 3 is switched off, and the leakage resistance R1 on the battery assembly side and the leakage resistance on the load side in a state where the contactor 3 is switched on. The combined resistance Rt of R2 is detected, and from these resistance values, it is determined whether the leakage site is on the battery assembly side or the load side.

The assembled battery for an electric vehicle of the present invention can be suitably used for an electric vehicle or a hybrid vehicle as an assembled battery provided with a leakage detection circuit .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram detailing a method for detecting leakage of an assembled battery for an electric vehicle according to an embodiment of the present invention, and is a block circuit diagram illustrating a state in which the assembled battery for the electric vehicle is mounted on the vehicle. It is a flowchart which shows the leakage detection method of the assembled battery for electric vehicles concerning one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Battery assembly 2 ... Load 3 ... Contactor 4 ... Converter 5 ... Motor 6 ... Control circuit 9 ... Battery assembly 10 ... Battery 11 ... Electric leakage detection circuit 12 ... Voltage detection means 13 ... Voltage detection circuit 14 ... Voltage detection circuit 15 ... Electric leakage Detector Ra ... Earth leakage detection resistor Rb ... Earth leakage detection resistor SW1 ... Earth leakage detection switch SW2 ... Earth leakage detection switch

Claims (1)

A battery set formed by connecting a plurality of batteries;
Two battery terminals on the high voltage side and low voltage side of the battery set are connected to the ground, the battery terminal on the high voltage side and the ground, and the battery terminal on the low voltage side In an assembled battery for an electric vehicle including a leakage detection circuit in which a leakage detection resistor and a leakage detection switch are arranged in series between the ground and the ground, and a load connected to the output side via a contactor,
The leakage detection switch on the high voltage side and the leakage detection switch on the low voltage side are configured to be openable and closable at individual timings,
The leakage detection circuit uses a voltage detection unit that detects a voltage of the leakage detection resistor, and a voltage of the leakage detection resistor that the voltage detection unit detects for a plurality of states in which the leakage detection switch is controlled to be turned on and off. A leakage calculation unit for calculating a leakage resistance;
The leakage calculation unit calculates a leakage resistance on the battery assembly side in a state where the contactor is turned off, and combines the leakage resistance on the battery assembly side and the leakage resistance on the load side in a state where the contactor is turned on. Calculate the resistance, calculate the load side leakage resistance from this combined resistance and the battery set side leakage resistance,
A preset resistance is set in advance, the set resistance is compared with each leakage resistance, and if the leakage resistance on the battery set side is smaller than the set resistance, it is determined that the leakage is on the battery set side, and the load side An assembled battery for an electric vehicle is configured to determine that the load-side leakage is present when the leakage resistance of the battery is smaller than the set resistance.

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