JP2018064334A - Power supply management device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply management device capable of suppressing deterioration in a secondary battery in consideration of various conditions.SOLUTION: A power supply management device includes: a voltage detector 20 for detecting voltage between terminals of a secondary battery 13; a switch 18 for opening and closing a power supply line to the secondary battery 13; and a controller 22 for limiting input voltage to the secondary battery 13 on the basis of prescribed conditions in accordance with the voltage between terminals and a duration time of a state in which the voltage between terminals is equal to or larger than a threshold value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power management device that suppresses deterioration of a secondary battery mounted on, for example, a hybrid vehicle.

  2. Description of the Related Art Conventionally, secondary batteries that can be charged and discharged have been adopted in vehicles such as hybrid vehicles. Generally, in a hybrid vehicle, electric power regenerated during vehicle deceleration is charged to a secondary battery to improve fuel efficiency. A secondary battery deteriorates due to aging, and if the deterioration progresses and the battery life is reached, sufficient functions are not exhibited. Therefore, for example, Patent Document 1 discloses an apparatus that can achieve both improvement in fuel efficiency of a vehicle and extension of battery life.

JP 2010-115055 A

  Patent Document 1 aims to improve fuel efficiency and extend the life of the secondary battery. However, in order to extend the life of the secondary battery, it is necessary to consider conditions other than the fuel efficiency. . For example, it is desirable to suppress the deterioration of the secondary battery in consideration of various conditions such as the voltage between the terminals of the secondary battery and the temperature of the secondary battery.

  Accordingly, an object of the present invention made in view of the above problems is to provide a power management device capable of suppressing deterioration of a secondary battery in consideration of various conditions.

In order to solve the above problems, a power management device according to the first aspect of the present invention provides:
A power management device provided in a vehicle equipped with a secondary battery,
A voltage detector for detecting a voltage between terminals of the secondary battery;
Based on a predetermined condition according to the inter-terminal voltage and the duration of the state where the inter-terminal voltage is equal to or higher than a threshold, a control unit that limits the input voltage to the secondary battery,
Is provided.

The power management device according to the second aspect of the present invention further includes:
A switch for opening and closing a power supply line to the secondary battery;
The limitation is to turn off the switch.

A power management device according to the third aspect of the present invention provides:
The limitation is to reduce the input voltage to the secondary battery.

A power management device according to the fourth aspect of the present invention provides:
The predetermined condition includes a condition determined based on a function guarantee of the secondary battery and a condition determined based on a performance guarantee of the secondary battery.

Moreover, the power management device according to the fifth aspect of the present invention provides:
The function guarantee is based on at least preventing the cell from expanding.

A power management device according to the sixth aspect of the present invention provides:
The performance guarantee is based on at least the increase rate of the internal resistance of the secondary battery being less than a predetermined value.

A power management device according to the seventh aspect of the present invention provides:
A power management device provided in a vehicle equipped with a secondary battery,
A temperature detector for detecting the temperature of the secondary battery;
A control unit that limits the input voltage to the secondary battery based on a predetermined condition according to the temperature and a duration of a state where the temperature is equal to or higher than a temperature threshold;
Is provided.

  According to the power management device according to the first aspect of the present invention, it is possible to suppress deterioration of the secondary battery in consideration of the voltage between terminals of the secondary battery and the duration.

  According to the power management device according to the second aspect of the present invention, the power supply can be shut off by turning off the switch under a predetermined condition, and deterioration of the secondary battery can be suppressed.

  According to the power management device of the third aspect of the present invention, the deterioration of the secondary battery can be suppressed by lowering the input voltage under a predetermined condition.

  According to the power management device according to the fourth aspect of the present invention, since the conditions based on the function guarantee and the performance guarantee are taken into account, the charging performance of the battery can be sufficiently exhibited while sufficiently suppressing the deterioration.

  Since the power management device according to the fifth aspect of the present invention is based on at least preventing cell expansion as a function guarantee, it is possible to appropriately suppress deterioration of the secondary battery.

  According to the power management device according to the sixth aspect of the present invention, as a performance guarantee, since the increase rate of the internal resistance of the secondary battery is based on less than a predetermined value, the deterioration of the secondary battery is appropriately suppressed. can do.

  According to the power management device of the seventh aspect of the present invention, deterioration of the secondary battery can be suppressed in consideration of the temperature and duration of the secondary battery.

It is a block diagram which shows schematic structure of the storage battery system of Embodiment 1. FIG. 3 is a diagram illustrating a restriction region on the input voltage to the secondary battery in the first embodiment. 3 is a flowchart illustrating an operation of the power management apparatus according to the first embodiment. 3 is a block diagram illustrating a schematic configuration of a storage battery system according to Embodiment 2. FIG. FIG. 6 is a diagram showing a limited region of input voltage to the secondary battery in the second embodiment. 6 is a flowchart illustrating an operation of the power management apparatus according to the second embodiment.

  Embodiments of the present invention will be described below.

(Embodiment 1)
First, a storage battery system including the power management device 16 according to the embodiment of the present invention will be described. The storage battery system 10 is mounted on a vehicle such as a hybrid vehicle (HEV vehicle) having a regenerative power generation function, for example.

  As shown in FIG. 1, the storage battery system 10 includes an alternator 11, a starter 12, a first secondary battery 13, a second secondary battery 14, a load 15, and a power management device 16. . The alternator 11, the starter 12, the first secondary battery 13, the second secondary battery 14, and the load 15 are connected in parallel by the power management device 16.

  The alternator 11 is a generator and is mechanically connected to a vehicle engine. The alternator 11 can generate power by driving the engine. The power generated by the alternator 11 by driving the engine can be supplied to the first secondary battery 13, the second secondary battery 14, and the load 15 by adjusting the output voltage with a regulator. The alternator 11 can generate power by regeneration when the vehicle is decelerated. The electric power regenerated by the alternator 11 can be used for charging the first secondary battery 13 and the second secondary battery 14.

  Here, whether the first secondary battery 13 and the second secondary battery 14 are charged or discharged while the alternator 11 is being driven (during power generation) depends on the power consumption of the load 15 and the running state of the vehicle. It depends on etc. In general, charging and discharging of the first secondary battery 13 and the second secondary battery 14 are switched in a short time while the alternator 11 is being driven, that is, while the engine is being driven.

  Here, in the engine of the vehicle, for example, from the viewpoint of fuel saving or the like, the engine idling is stopped while the vehicle is temporarily stopped by the control of the ECU. Therefore, the alternator 11 stops power generation during the temporary stop of the traveling of the vehicle.

  The starter 12 includes a cell motor, for example, and receives power supply from at least one of the first secondary battery 13 and the second secondary battery 14 to start the vehicle engine. In the present embodiment, the starter 12 receives power supply from the second secondary battery 14 after the ignition of the vehicle is turned on, and starts the engine.

  The first secondary battery 13 is a secondary battery other than a lead storage battery, such as a lithium ion battery or a nickel metal hydride battery. In the present embodiment, the output voltage of the first secondary battery 13 is substantially the same as the output voltage of the second secondary battery 14 and is, for example, 12V. Alternatively, the output voltage of the first secondary battery 13 may be different from the output voltage of the second secondary battery 14. In such a case, the output voltage of the first secondary battery 13 is adjusted by the DC / DC converter so as to be substantially the same as the output voltage of the second secondary battery 14. The first secondary battery 13 supplies power to the starter 12, the load 15, the ECU, and the like when the engine drive is stopped (idling is stopped), that is, when the power generation by the alternator 11 is stopped. Is possible.

  The second secondary battery 14 is a lead storage battery having an output voltage of a nominal voltage of 12 V, for example, and can supply power to the load 15.

  The load 15 is a load 15 including, for example, an audio, an air conditioner, and a navigation system provided in the vehicle, and operates by consuming the supplied power. The load 15 operates by receiving power supply from the first secondary battery 13 and the second secondary battery 14 while the engine drive is stopped (when power generation by the alternator 11 is stopped), and the alternator is operated while the engine is driven. 11, receiving power supply from the first secondary battery 13 and the second secondary battery 14.

  The power management device 16 includes a first switch 17, a second switch 18, a third switch 19, a voltage detection unit 20, a communication unit 21, and a control unit 22.

  The first switch 17 includes a relay circuit, for example, and is a switch connected in series with the starter 12. The first switch 17 connects or disconnects the starter 12 in parallel with other components.

  The second switch 18 includes a relay circuit, for example, and is a switch connected in series with the first secondary battery 13. The second switch 18 connects or disconnects the first secondary battery 13 in parallel with other components. Hereinafter, the power line for supplying the output power of the first secondary battery 13 to the vehicle (other components) is referred to as a power supply line. That is, the second switch 18 is provided on the power supply line. The second switch 18 corresponds to the “switch” of the present invention.

  The third switch 19 includes a relay circuit, for example, and is a switch connected in series with the second secondary battery 14 and the load 15. The third switch 19 connects or disconnects the second secondary battery 14 and the load 15 in parallel with other components.

  The voltage detection unit 20 detects an inter-terminal voltage (CCV: Close Circuit Voltage) of the first secondary battery 13.

  The communication unit 21 is an interface that transmits and receives information via an in-vehicle network such as CAN. The communication unit 21 can acquire various control information of the vehicle via the in-vehicle network.

  The control unit 22 is, for example, a dedicated microprocessor or a general-purpose CPU that executes a specific process by reading a specific program. The control unit 22 controls the overall operation of the power management device 16.

  For example, the control unit 22 controls the operations of the first switch 17, the second switch 18, and the third switch 19, respectively, and the alternator 11, the first secondary battery 13, and the second secondary battery. Power supply by 14 and charging of the first secondary battery 13 and the second secondary battery 14 are performed.

  Here, as described above, the first secondary battery 13 is a high-density energy battery such as a lithium ion battery. The control unit 22 is based on a predetermined condition in accordance with the voltage between the terminals of the first secondary battery 13 and the time during which the voltage between the terminals is equal to or higher than the threshold (hereinafter referred to as duration). The input voltage to the first secondary battery 13 is limited. Thereby, deterioration of the first secondary battery 13 is suppressed.

  FIG. 2 is a diagram showing each predetermined condition as a region on a coordinate with the vertical axis representing the voltage between terminals and the horizontal axis representing the duration. When the condition of the region 31 or 32 in FIG. 2 is satisfied, the control unit 22 limits the input voltage to the first secondary battery 13. Hereinafter, each region will be described.

Region 31 is a terminal voltage threshold V ₁ or more, the duration of the state the terminal voltage is the threshold value V ₁ above is the area corresponding to the condition of the at t ₁ or more. When the condition of the region 31 is satisfied, the control unit 22 turns off the second switch 18 and stops the power supply to the first secondary battery 13. Here, the threshold values V ₁ and t ₁ are determined based on the function guarantee of the first secondary battery 13. The function guarantee is a standard for guaranteeing the minimum function of the first secondary battery 13. For example, the functional guarantee is determined based on the fact that the structural change (breaking, deformation, cell electrolyte leakage, safety valve operation, etc.) of the first secondary battery 13 does not occur.

Region 32, (i) terminal voltage threshold _{V 2} or more and less than _{V 1,} if the duration of the state the voltage between terminals is less than the threshold value _{V 2} or more and _{V 1} is at _{t 2} or more, and (ii ) in terminal voltage is less than the threshold V ₃ or more and V _2, in a region where the duration of the state the terminal voltage is lower than the threshold V ₃ or more and V ₂ corresponding to two patterns condition when at t ₃ or more is there. When the condition of the region 32 is satisfied, the control unit 22 decreases the input voltage to the first secondary battery 13. Specifically, the control unit 22 transmits a charge restriction request for lowering the input voltage to the first secondary battery 13 via the communication unit 21, and lowers the input voltage by the alternator 11. Here, the threshold values V ₂ and t ₂ and the threshold values V ₃ and t ₃ are determined based on the performance guarantee of the first secondary battery 13. The performance guarantee is a standard for guaranteeing a certain level of performance of the first secondary battery. For example, the performance guarantee is determined on the basis that the increase rate of the internal resistance of the first secondary battery 13 is less than a predetermined value. Or you may determine on the basis that the speed of the capacity | capacitance fall of the 1st secondary battery 13 shall be less than predetermined value. If the performance guarantee is satisfied, the function guarantee is satisfied.

  The region 33 is a region other than the region 31 and the region 32 and can be used normally. That is, when the condition of the area 33 is satisfied, the function guarantee and the performance guarantee are satisfied. When the condition of the region 33 is satisfied, the control unit 22 does not limit the input voltage to the first secondary battery 13.

  Next, the operation of the power management device 16 according to the first embodiment of the present invention will be described with reference to the flowchart shown in FIG.

First, the control unit 22 monitors the inter-terminal voltage during charging of the first secondary battery 13 (step S10). Next, the control unit 22 determines whether or not the monitored inter-terminal voltage is equal to or higher than a threshold value (V ₁ , V _2, or V ₃ ) (step S20). If the inter-terminal voltage is greater than or equal to the threshold value, the process proceeds to step S30. When the voltage between the terminals is less than the threshold value, the process returns to step S10.

When the voltage between the terminals is equal to or greater than the threshold, the control unit 22 determines whether or not the duration is equal to or greater than a predetermined time (t ₁ , t _2, or t ₃ ) corresponding to the duration (step S30). If the duration is longer than the predetermined time, the process proceeds to step S40. If the duration is not longer than the predetermined time, the process returns to step S10. The control unit 22 specifically, when the terminal voltage is determined to be V ₁ or more at step S20, the duration in step S30 is equal to or t ₁ or more. The control unit 22, when the terminal voltage is determined to be V ₂ or more in step S20, the duration in step S30 is equal to or t ₂ or more. In addition, when it is determined in step S20 that the voltage between the terminals is V ₃ or more, the control unit 22 determines whether or not the duration is t ₃ or more in step S30.

  When the duration is equal to or longer than the predetermined time, the control unit 22 limits the input voltage to the first secondary battery 13 (step S40). Specifically, the control unit 22 turns off the second switch 18 and stops the power supply to the first secondary battery 13. Alternatively, the control unit 22 decreases the input voltage to the first secondary battery 13. Then, the process ends.

  As described above, according to the power management device 16 according to the first embodiment, the input voltage is limited in consideration of the voltage between the terminals of the first secondary battery 13 and the duration, and thus the first secondary battery is appropriately set. Deterioration of the battery 13 can be suppressed.

  Further, since the second switch 18 is turned off under the conditions corresponding to the region 31 and the power supply to the first secondary battery 13 is stopped, deterioration of the first secondary battery 13 can be appropriately suppressed. . Here, since the condition corresponding to the region 31 is determined based on the function guarantee, it is possible to appropriately suppress the deterioration of the first secondary battery 13 within a range satisfying the function guarantee.

  Further, in order to lower the input voltage to the first secondary battery 13 under the conditions corresponding to the region 32, the charging performance of the first secondary battery 13 is appropriately suppressed while suppressing the deterioration of the first secondary battery 13. Can be demonstrated. Here, since the conditions corresponding to the region 32 are determined based on the performance guarantee, it is possible to appropriately suppress the deterioration of the first secondary battery 13 within a range satisfying the performance guarantee. As described above, in this embodiment, optimum conditions are provided according to the conditions of the voltage between terminals and the duration. Specifically, in this embodiment, since two conditions, a condition related to function guarantee and a condition related to performance guarantee, are provided, the deterioration of the first secondary battery 13 is appropriately suppressed according to each state. However, the charging performance of the first secondary battery can be exhibited.

  In the present embodiment, the control unit 22 reduces the input voltage to the first secondary battery 13 when the condition of the region 32 is satisfied, but the input voltage may be set to zero. In this case, the control unit 22 transmits a request (charging stop request) for setting the input voltage to the first secondary battery 13 to 0 through the communication unit 21 and stops charging by the alternator 11.

Incidentally, higher predetermined threshold value or the inter-terminal voltage is higher than the threshold V ₁ (hereinafter referred to as V _x.) Above there, and the duration of the state the inter-terminal voltage is equal to or more than the threshold V _x is t _x or more (t x _{<t In the case of 1} ), the control unit 22 may transmit a request to stop the engine. In the said area | region, the possibility that the 1st secondary battery 13 has failed is high. Therefore, by controlling in this way, it is possible to appropriately cope with the case where the first secondary battery 13 is out of order.

  In the present embodiment, the voltage between terminals and the duration time are individually determined. That is, the voltage between terminals is determined by comparing with a threshold value in step S20, and the duration is determined by comparing with a predetermined time in step S30. However, the determination method is not limited to this. For example, the input voltage may be limited by multiplying the inter-terminal voltage and the duration time as a threshold value and comparing the threshold value with a time integral value of the inter-terminal voltage. By doing so, for example, when the voltage between terminals is high, the input voltage can be more appropriately limited, such as satisfying a predetermined condition even if the duration is short.

(Embodiment 2)
The second embodiment of the present invention will be described below. FIG. 4 is a block diagram showing a schematic configuration of the storage battery system 10b according to the second embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. The power management device 16b according to the second embodiment is different from the configuration according to the first embodiment in that a temperature detection unit 23 is provided instead of the voltage detection unit 20.

  The temperature detector 23 detects the temperature of the first secondary battery 13 (hereinafter referred to as the battery temperature). Then, the control unit 22b according to the second embodiment supplies the first secondary battery 13 to the first secondary battery 13 based on a predetermined condition corresponding to the battery temperature and the duration of the state where the battery temperature is equal to or higher than the threshold (temperature threshold). Limit the input voltage.

  FIG. 5 is a diagram showing each predetermined condition in each region on the coordinates where the vertical axis is the battery temperature and the horizontal axis is the duration. When the condition of the region 34 or 35 in FIG. 5 is satisfied, the control unit 22b limits the input voltage to the secondary battery 13. Hereinafter, each region will be described.

Region 34, the battery temperature threshold value above T _1, a region where the duration of the state the battery temperature is the threshold value above T ₁ corresponds to the condition of the at t ₄ or more. In the case of the region 34, the control unit 22 b turns off the second switch 18 and stops the power supply to the first secondary battery 13. Here, the threshold values T ₁ and t ₁ are determined based on the function guarantee of the first secondary battery 13.

Region 35, in less than ₁ T and the battery temperature threshold value T ₂ or more, an area in which the duration of the state the battery temperature is the threshold value T ₂ or more and less than T ₁ corresponds to the condition of the at t ₄ or more. In the case of the region 35, the control unit 22 decreases the input voltage to the first secondary battery 13. Specifically, the control unit 22b transmits a charge restriction request for lowering the input voltage to the first secondary battery 13 via the communication unit 21, and lowers the input voltage by the alternator 11. Here, the threshold values T ₂ and t ₄ are determined based on the performance guarantee of the first secondary battery 13.

  The area 36 is an area other than the areas 34 and 35 and can be used normally. That is, when the condition corresponding to this area 36 is satisfied, the function guarantee and the performance guarantee are satisfied. When the condition of the region 36 is satisfied, the control unit 22b does not limit the input voltage to the first secondary battery 13.

  Next, the operation of the power management device 16b according to the second embodiment of the present invention will be described with reference to the flowchart shown in FIG.

First, the controller 22b monitors the battery temperature during charging of the first secondary battery 13 (step S10b). Next, the control unit 22 determines whether or not the monitored battery temperature is equal to or higher than the temperature threshold (T ₁ or T ₂ ) (step S20b). When the battery temperature is equal to or higher than the temperature threshold, the process proceeds to step S30b. When the battery temperature is lower than the temperature threshold, the process returns to step S10b.

If the temperature is above the threshold value, the control unit 22b, the duration is equal to or a predetermined time t ₄ or more (step S30b). If the duration is greater than or equal to the predetermined time, the process proceeds to step S40b. If the duration is not longer than the predetermined time, the process returns to step S10b.

  When the duration is equal to or longer than the predetermined time, the controller 22b limits the input voltage to the first secondary battery 13 (step S40b). Specifically, the control unit 22 turns off the second switch 18 and stops the power supply to the first secondary battery 13. Alternatively, the control unit 22 decreases the input voltage to the first secondary battery 13. Then, the process ends.

  As described above, according to the power management device 16b according to the second embodiment, the input voltage is limited in consideration of the battery temperature and the duration of the first secondary battery 13, and accordingly, the first secondary battery is appropriately provided. 13 deterioration can be suppressed.

  In the present embodiment, the control unit 22b reduces the input voltage to the first secondary battery 13 when the condition of the region 35 is satisfied, but the input voltage may be set to zero. In this case, the control unit 22b transmits a request (charging stop request) for setting the input voltage to the first secondary battery 13 to 0 through the communication unit 21, and stops charging by the alternator 11.

  In the present embodiment, the battery temperature and the duration time are individually determined. That is, the temperature is determined by comparing with a temperature threshold value in step S20b, and the duration is determined by comparing with a predetermined time in step S30b. However, the determination method is not limited to this. For example, the input voltage may be limited by comparing the threshold value with the time integral value of the battery temperature, using a multiplication value of the temperature threshold value and the duration time as a threshold value. By doing so, for example, when the battery temperature is high, the input voltage can be more appropriately limited such that the predetermined condition is satisfied even if the duration is short.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, the functions included in each means, each step, etc. can be rearranged so that there is no logical contradiction, and a plurality of means, steps, etc. can be combined or divided into one. .

DESCRIPTION OF SYMBOLS 10, 10b Storage battery system 11 Alternator 12 Starter 13 1st secondary battery 14 2nd secondary battery 15 Load 16, 16b Power supply management apparatus 17 1st switch 18 2nd switch 19 3rd switch 20 Voltage detection part 21 communication part 22, 22b control part 22b control part 23 temperature detection part 31-36 area | region

Claims (7)

A power management device provided in a vehicle equipped with a secondary battery,
A voltage detector for detecting a voltage between terminals of the secondary battery;
Based on a predetermined condition according to the inter-terminal voltage and the duration of the state where the inter-terminal voltage is equal to or higher than a threshold, a control unit that limits the input voltage to the secondary battery,
A power management device comprising: The power management device further includes
A switch for opening and closing a power supply line to the secondary battery;
The power management apparatus according to claim 1, wherein the restriction is to turn off the switch.   The power management apparatus according to claim 1, wherein the restriction is to lower an input voltage to the secondary battery.   4. The predetermined condition includes a condition determined based on a function guarantee of the secondary battery and a condition determined based on a performance guarantee of the secondary battery. 5. Power management device.   The power management device according to claim 4, wherein the function guarantee is based on a fact that a structural change of the secondary battery does not occur.   The power management device according to claim 4, wherein the performance guarantee is based on at least a rate of increase in internal resistance of the secondary battery being less than a predetermined value. A power management device provided in a vehicle equipped with a secondary battery,
A temperature detector for detecting the temperature of the secondary battery;
A control unit that limits the input voltage to the secondary battery based on a predetermined condition according to the temperature and a duration of a state where the temperature is equal to or higher than a temperature threshold;
A power management device comprising:

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