JP2023063123A - Battery protection device - Google Patents

Abstract

To provide a technology that can appropriately protect a battery even for an external charger having various performances and qualities.SOLUTION: There is provided a battery protection device to be installed in a vehicle. The battery protection device has a relay provided between the battery and a circuit on the vehicle side, and a control device capable of monitoring the battery voltage while the vehicle is parked and executing a protection process to open the relay when the battery voltage or a change thereof indicates a predetermined abnormality. The control device suspends the execution of the protection process when the daily change width of the voltage of the battery is equal to or less than a predetermined first upper limit value.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The technology disclosed in this specification relates to a battery protection device, and more particularly to a battery protection device mounted on a vehicle.

Patent Literature 1 discloses a protection device for a battery mounted on a vehicle. The battery is configured to be rechargeable by a solar cell, and the protection device is configured to stop charging when the voltage of the battery exceeds a reference value during charging by the solar cell.

JP 2005-287118 A

A user may use a so-called third-party charger to charge a battery mounted in a vehicle. The performance and quality of non-genuine chargers vary, and there are some that charge the battery harmfully. For such chargers, it is preferable that a battery protection device is activated to protect the battery from harmful charging. On the other hand, some of the chargers sold by other companies charge the battery in a harmless manner. For such chargers, it is preferable to allow charging of the battery without activation of the battery protection device. However, in the prior art, there is a problem that even a charger that performs harmless charging may be prohibited from charging due to activation of a battery protection device, which impairs convenience for the user. rice field.

In view of the above, this specification provides a technology that can appropriately protect the battery even for chargers that are non-genuine products with various performances and qualities.

This specification discloses a protection device for a battery mounted on a vehicle. The protection device monitors the voltage of the battery while the vehicle is parked, and opens the relay when the voltage of the battery or its change indicates a predetermined abnormality. and a control device capable of executing the protection process to prevent the loss of power, and the control device suspends the execution of the protection process when the variation of the battery voltage per day is equal to or less than a predetermined first upper limit value.

In the protection device described above, the voltage of the battery is monitored while the vehicle is parked, and when the voltage of the battery or its change indicates a predetermined abnormality (for example, overcharge or overdischarge), protective processing is executed to open the relay. be. Therefore, when the battery is overcharged or overdischarged, or when harmful charging is performed by a non-genuine charger, the battery can be protected by releasing the relay. On the other hand, this protective device also monitors the variation width of the battery voltage per day, and is configured to interrupt the execution of the protection process when the variation width is equal to or less than a predetermined first upper limit value. It is Normally, even in a parked vehicle, the power of the battery is consumed, which causes the voltage of the battery to drop. However, when no such change is observed in the battery voltage and the width of change in the battery voltage per day is equal to or less than the first upper limit value, the battery is being slowly charged by, for example, a non-genuine charger. can be determined to be Since such charging is harmless to the battery, it is possible to prevent the charging from being unintentionally prohibited by interrupting the execution of the protection process. As described above, according to the protection device described above, it is possible to appropriately protect the battery even from external chargers having various performances and qualities.

2 is a block diagram showing the configuration of a battery unit 20; FIG. 4 is a flow diagram for explaining protection processing of the protection device 10. FIG. 4 is a graph showing the relationship between the remaining battery charge and the voltage of the battery 12; A specific example of a charger that is harmful to battery 12 is shown. A specific example of a charger that is harmless to the battery 12 is shown.

In an embodiment of the present technology, the control device provides protection even when the hourly average voltage of the battery shows an upward trend and the hourly change width of the average voltage is equal to or less than a predetermined second upper limit value. Execution of processing may be interrupted. According to such a configuration, it is possible to more accurately identify charging that is harmless to the battery and to allow the charging by interrupting execution of the protection process.

(Embodiment) A battery unit 20 having a protective device 10 will be described with reference to the drawings. The battery unit 20 includes a battery 12 and a current sensor 18 in addition to the protection device 10 . The battery unit 20 is mounted on the vehicle. The battery unit 20 includes a positive terminal 20a and a negative terminal 20b. Each of the positive terminal 20a and the negative terminal 20b of the battery unit 20 is connected to a vehicle-side circuit (not shown). Current sensor 18 is provided between negative electrode 12 b of battery 12 and negative electrode terminal 20 b of battery unit 20 . Current sensor 18 detects the value of current flowing through battery unit 20 .

The battery 12 is, for example, a 12-volt auxiliary battery. Battery 12 is connected to and powers the various control systems and other accessories of the vehicle. The battery 12 is composed of a plurality of battery cells. The battery 12 can be charged by a main battery (not shown) of the vehicle, or by power supplied from a third-party charger or the like when the vehicle is parked. Although not particularly limited, the battery 12 of this embodiment is a lithium battery, such as a lithium iron phosphate (LFP) battery.

The protection device 10 is a device that protects the battery 12 . For example, the protection device 10 monitors the voltage of the battery 12 while the vehicle is parked, and when the battery 12 is in a state of overcharge or overdischarge, or when harmful charging is performed by a non-genuine charger. , is configured to protect the battery 12 . The protective device 10 includes a latch relay (also called a latching relay) 14 and an ECU (Electronic Control Unit) 16 . Here, the latch relay 14 is an example of a "relay" in the technology disclosed in this specification, and the ECU 16 is an example of a "control device" in the technology disclosed in this specification.

A latch relay 14 is provided between the battery 12 and a circuit on the vehicle side. One end of the latch relay 14 is connected to the positive electrode 12 a of the battery 12 . The other end of the latch relay 14 is connected to a positive terminal 20a connected to a circuit on the vehicle side. The circuit on the vehicle side and the battery 12 are disconnected/connected by opening/closing the latch relay 14 . Normally, the latching relay 14 is closed and the battery 12 and the vehicle side circuitry are connected to each other.

The ECU 16 is connected to the positive electrode 12 a and the negative electrode 12 b of the battery 12 . The ECU 16 measures and monitors the voltage of the battery 12 while the vehicle is parked. In addition, the voltage here means a closed circuit voltage (CCV). The relationship between voltage (ie CCV) and remaining battery charge (so-called SOC) is shown in FIG. Thereby, the ECU 16 can estimate the remaining battery capacity from the voltage. This estimation is hereinafter referred to as CCV-SOC estimation. The ECU 16 determines the state of the battery 12 based on the CCV-SOC estimation. When a non-genuine charger is connected to the battery 12, the voltage measured by the ECU 16 indicates the charging voltage applied to the battery 12 by the charger. Therefore, although the details will be described later, the execution of CCV-SOC estimation is suspended while the battery 12 is being charged, for example, by using a non-genuine charger.

The ECU 16 is connected to the latch relay 14 and controls the operation of the latch relay 14 . The ECU 16 executes protection processing of the battery 12 when the measured voltage of the battery 12 indicates a predetermined abnormality. In this protection process, the ECU 16 opens the latch relay 14 to electrically disconnect the battery 12 from the vehicle-side circuit. This avoids further discharging or charging of the battery 12 when the battery 12 exhibits an overcharged condition (i.e., (Z) in FIG. 3) or an over-discharged condition (i.e., (X) in FIG. 3). be. Also, for example, when a non-genuine charger is connected to the battery 12 and the measured voltage of the battery 12 changes suddenly, the ECU 16 determines that the charging is harmful to the battery 12 and removes the battery 12 from the vehicle side. It can be electrically disconnected from the circuit (ie the charger).

The ECU 16 also monitors the variation of the voltage of the battery 12 per day. The ECU 16 determines that the battery 12 is slowly being charged by, for example, a non-genuine charger (that is, (Y) in FIG. 3) when the width of change is equal to or less than a predetermined first upper limit value. At this time, the ECU 16 suspends execution of the protection process. The first upper limit is, for example, approximately 0.1 volts/day. The ECU 16 also suspends the execution of the protection process when the hourly average voltage of the battery 12 shows an upward trend and the hourly variation of the average voltage is equal to or less than the second upper limit value. . According to such a configuration, charging that is harmless to the battery 12 can be more accurately identified and allowed by interrupting execution of the protection process. The second upper limit is, for example, approximately 0.05 volts/hour. Note that while the battery 12 is being charged, the voltage measured by the ECU 16 indicates the charging voltage applied to the battery 12 and does not necessarily correspond to the SOC of the battery 12 . Accordingly, the ECU 16 suspends the CCV-SOC estimation at the same time as suspending the execution of the protection process.

The ECU 16 is communicably connected to the current sensor 18 . The ECU 16 receives detection data from the current sensor 18 and determines the state of the battery 12 based on the detected data.

A vehicle battery is sometimes charged by a user using a so-called aftermarket charger. The performance and quality of non-genuine chargers vary, and there are some that charge the battery harmfully. For such chargers, it is preferable that a battery protection device is activated to protect the battery from harmful charging. On the other hand, some of the chargers sold by other companies charge the battery in a harmless manner. For such chargers, it is preferable to allow charging of the battery without activation of the battery protection device. However, in the prior art, there is a problem that even a charger that performs harmless charging may be prohibited from charging due to activation of a battery protection device, which impairs convenience for the user. rice field.

In order to solve the above problem, the protective device 10 of the present embodiment monitors the voltage of the battery 12 while the vehicle is parked, and the voltage of the battery 12 or its change indicates a predetermined abnormality (eg, overcharge or overdischarge). When indicated, protective processing is executed to open the latch relay 14 . Therefore, when the battery 12 is overcharged or overdischarged, or when harmful charging is performed by an external charger, the battery 12 can be protected by releasing the latch relay 14.例文帳に追加On the other hand, the protective device 10 also monitors the variation width of the voltage of the battery 12 per day, and when the variation width is equal to or less than a predetermined first upper limit value, execution of the protection process is interrupted. is configured to Normally, even in a parked vehicle, the electric power of the battery 12 is consumed, and the voltage of the battery 12 decreases accordingly. However, when no such change is seen in the voltage of the battery 12 and the width of change in the voltage of the battery 12 per day is equal to or less than the first upper limit value, the battery 12 is slowly restored by, for example, a non-genuine charger. It can be determined that the battery is charged. Since such charging is harmless to the battery 12, it is possible to avoid unintentional prohibition of the charging due to interruption of the protection process. Thus, according to the protection device 10 described above, it is possible to appropriately protect the battery 12 from chargers that are external products with various performances and qualities.

A series of processes executed by the protective device 10 will be described with reference to FIGS. 2 and 3. FIG. First, in step S12, the protective device 10 determines whether the vehicle is in the Ready-OFF state and the current is a predetermined value, for example, about 0.1 ampere or less. Here, the Ready-OFF state means that the ignition switch is turned off and the vehicle is parked. Immediately after parking with the ignition switch turned off, various systems in the vehicle are in operation and consume power. After waiting for a certain period of time after the ignition switch is turned off, when the current becomes 0.1 ampere or less, the protective device 10 judges that the vehicle is completely parked, and proceeds to the processing of S14. It should be noted that the protection device 10 enables CCV-SOC estimation and protection processing at the same time it determines that the vehicle is fully parked.

Next, in step S14, protection device 10 determines whether the voltage of battery 12 has changed significantly. Specifically, when the protection device 10 detects that the voltage change width ΔVh per hour of the battery 12 is about 0.5 volts or less, or the voltage change width ΔVs per second of the battery 12 is about 0.3 volts or less. Determine whether or not When this condition is satisfied, the protective device 10 determines that the measured voltage of the battery 12 has not changed suddenly (Yes in S14), and proceeds to the process of S16. On the other hand, if this condition is also not satisfied (No in S14), the protective device 10 determines that there is a possibility of unintended over-discharging or over-charging of the battery 12 ((X) or (Z) in FIG. 3). , S24 to execute protection processing.

In step S16, the protection device 10 determines whether or not the daily change width ΔVd of the voltage of the battery 12 is gradually changing. Specifically, the protection device 10 determines whether the daily variation ΔVd is less than or equal to about 0.1 volts. When the variation width ΔVd per day is about 0.1 volt or less (Yes in S16), the protective device 10 determines that the battery 12 is being charged by a harmless charger, proceeds to the processing of S22, and performs protective processing. interrupt the execution of When the variation width ΔVd per day is greater than about 0.1 volt (No in S16), the process proceeds to S18.

In step S18, the protective device 10 determines whether or not the daily change width ΔVd tends to increase. When the variation width ΔVd per day tends to increase (Yes in S18), the process proceeds to S20. When the variation width ΔVd per day tends to decrease (No in S18), the protective device 10 determines that the battery 12 may be discharged normally, proceeds to the process of S24, and executes the protective process.

In step S20, the protective device 10 determines whether or not the width of change ΔVh per hour is moderate. Specifically, the protective device 10 determines whether or not the change width ΔVh per hour is 0.05 volts or less. When the change width ΔVh per hour is 0.05 volts or less (Yes in S20), the process proceeds to S22, the protective device 10 determines that the battery 12 is being charged by a harmless charger, and performs protective processing. interrupt the execution of When the change width ΔVh per hour is larger than 0.05 volts (No in S20), the process proceeds to S24, the protection device 10 determines that the battery 12 may be overcharged, and executes the protection process. do.

(Specific Example 1) With reference to FIG. 4, a specific example 1 will be described in which an unsuitable external charger is used for the battery 12 and the battery 12 is charged harmfully. At time T1, the ignition (IG) signal was turned off and the vehicle was parked. At this time, in the flow of FIG. 2, it progresses to Yes by S12. As soon as the vehicle was parked, the judgment of protective treatment was validated. After parking, the ΔV decrease flag is turned on due to the discharge normally occurring. At time T2, charging was started by a non-genuine charger. The voltage rapidly increased from time T2, and at time T3, the voltage measured by the ECU 16 increased from 13.5 volts to a maximum of 14.6 volts. At this time, the voltage increase flag is turned on, and the overvoltage determination is turned on by the ECU 16 . Therefore, according to the flow of FIG. 2, the protective device 10 determined that there is a possibility of overcharging, and proceeded to No in S14. Then, in S24, protection processing is executed, and at time T4, the latch relay 14 is opened. Therefore, when a charger that is harmful to the battery 12 is used, the battery 12 is protected.

(Concrete Example 2) Concrete Example 2 in which the battery 12 is charged using a charger harmless to the battery 12 will be described with reference to FIG. At time T5, the IG signal was turned off and the vehicle was parked. At this time, in the flow of FIG. 2, it progresses to Yes by S12. As soon as the vehicle was parked, the judgment of protective treatment was validated. After parking, the ΔV decrease flag was turned on due to discharge that normally occurs. At time T6, charging was started by a non-genuine charger. At this time, the measured voltage of the ECU 16 showed a constant value, and the short-term ΔV constant flag was turned on. At this time, in the flow of FIG. 2, the process proceeds from S14 to S18 via S16. Here, the short-term ΔV constant flag is turned on when the voltage change width ΔVm per minute is 0.1 volt or less. After time T7 and time T8, the voltage gradually increases (proceeding to S20), the long-term ΔV constant flag is turned on, and the process proceeds to Yes in S20. Here, the long-term constant ΔV flag is turned on when the voltage change width ΔVh per hour is about 0.05 volt or less. Then, in S22, execution of the protection process is interrupted, and the latch relay 14 remains closed. Therefore, when a charger harmless to the battery 12 was used, the execution of the battery 12 protection process was interrupted, and charging by a non-genuine charger was permitted.

Although specific examples of the technology disclosed in this specification have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims as filed. The techniques exemplified in this specification or drawings can achieve a plurality of purposes at the same time, and achieving one of them has technical utility in itself.

10: Protective Device 12: Battery 14: Latch Relay 16: ECU
18: Current sensor 20: Battery unit

Claims (2)

A protection device for a battery mounted on a vehicle,
a relay provided between the battery and a circuit on the vehicle side;
a control device capable of monitoring the voltage of the battery while the vehicle is parked and executing a protection process of opening the relay when the voltage of the battery or a change in the voltage of the battery indicates a predetermined abnormality;
The control device interrupts the execution of the protection process when the daily change width of the voltage of the battery is equal to or less than a predetermined first upper limit value.
protector. The control device also executes the protection process when the hourly average voltage of the battery shows an upward trend and when the hourly variation width of the average voltage is equal to or less than a predetermined second upper limit value. 2. The protective device of claim 1, interrupting.

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