JP2016117354A - Power supply management apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately manage an SOC while suppressing the frequent switching of a relay for connecting batteries.SOLUTION: A power supply management apparatus (100) comprises: detection means (20) detecting an SOC of each of two or more batteries mounted in a vehicle; priority setting means (20) setting a charge/discharge priority of each of the two or more batteries on the basis of the detected SOC; and control means (20) setting a demanded voltage related to the battery given the highest set priority as a power generation voltage of power supply means (11) of the vehicle. The priority setting means sets higher each priority as the detected SOC for each of the two or more batteries is closer to an upper limit value or a lower limit value of an appropriate range of the SOC set in advance for each of the two or more batteries.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a technical field of a power management device for a vehicle such as an automobile.

  As this type of device, for example, a lead storage battery and a lithium storage battery are connected in parallel, and a MOS-FET that switches between energization and shutoff between the generator and the lithium storage battery, and the MOS-FET and the lithium storage battery are disposed between the MOS-FET and the lithium storage battery. And a relay that switches between energization and interruption of the lithium storage battery, and when the remaining capacity of the lithium storage battery is higher than the appropriate range, the MOS-FET interrupts the energization between the generator and the lithium storage battery, and the relay Has been proposed (see Patent Document 1).

  Alternatively, the system includes a plurality of batteries, and distributes the charge / discharge power value of the entire system to each battery periodically or at an arbitrary timing, and is based on deterioration characteristics relating to SOC (State Of Charge) of each of the plurality of batteries. Thus, there has been proposed a system that prioritizes each of a plurality of batteries at each time point and distributes charge / discharge power values according to the priorities (see Patent Document 2).

JP 2011-176958 A JP 2014-171335 A

  According to the technology described in Patent Document 1, for example, when the remaining capacity of a lithium storage battery fluctuates in the vicinity of the boundary value of the appropriate range, switching of the relay opening / closing occurs relatively frequently, and the deterioration of the relay can proceed quickly. There is a technical problem that there is. The technique described in Patent Document 2 cannot solve this problem.

  The present invention has been made in view of the above-described problems, for example, and an object of the present invention is to provide a power management apparatus capable of appropriately managing the SOC of a battery while suppressing the switching frequency of relays.

  In order to solve the above-described problem, the power management device of the present invention corresponds to two or more batteries, a power generation unit, and the two or more batteries, and switches between energization and cutoff of the corresponding battery and the power generation unit. A power management apparatus for a vehicle, comprising: a plurality of relays; a detecting means for detecting an SOC related to each of the two or more batteries; and charging / discharging of each of the two or more batteries based on the detected SOC Priority setting means for setting the priority, and control means for setting, as a power generation voltage of the power generation means, a required voltage related to the battery having the highest priority set when the vehicle is not decelerated, The priority setting means, for each of the two or more batteries, the detected SOC approaches the upper limit value of the appropriate range of SOC predetermined for each of the two or more batteries, or the lower limit value. Zukuhodo, it sets higher the priority.

  According to the power management device of the present invention, the power management device corresponds to each of two or more batteries, a power generation unit, and the two or more batteries, and switches between energization and cutoff of the corresponding battery and the power generation unit. And a relay. That is, in the vehicle, a relay is disposed between each battery and the power generation means.

  The power management apparatus includes a detection unit, a priority setting unit, and a control unit.

  The detection means detects the SOC related to each of the two or more batteries. Since various known modes can be applied to the SOC detection method, a detailed description thereof will be omitted.

  For example, the priority setting means including a memory, a processor, etc. sets the charge / discharge priority of each of the two or more batteries based on the detected SOC. Here, in particular, the priority setting means, for each of the two or more batteries, as the detected SOC approaches the upper limit value of the appropriate range of the SOC determined in advance for each of the two or more batteries, or approaches the lower limit value. Set the priority higher.

  That is, in the present invention, the higher the priority is set for a battery that is more likely to be in an overcharged state or an overdischarged state.

  Note that various known modes can be applied to the method for setting the appropriate SOC range of each battery. For example, it may be set based on a characteristic curve indicating the relationship between the SOC of the battery and the open circuit voltage.

  For example, the control means including a memory, a processor, etc. sets the required voltage related to the set battery with the highest priority as the power generation voltage of the power generation means when the vehicle is not decelerated.

  Here, the “required voltage” is determined according to the SOC of the battery with the highest priority. Specifically, for example, when the SOC of the battery is a value in the vicinity of the upper limit value of the appropriate range, the required voltage is set to a voltage at which the battery is discharged. On the other hand, when the SOC of the battery is a value near the lower limit value of the appropriate range, the required voltage is set to a voltage that charges the battery.

  When the required voltage related to the battery with the highest priority is set as the power generation voltage of the power generation means, the other batteries are charged or discharged according to the relationship between the terminal voltage and the power generation voltage.

  According to the inventor's research, the following matters have been found. That is, when there is a high possibility that the battery will be in an overdischarged state or an overcharged state, the battery and the power generation means are often shut off by the relay (that is, the battery is disconnected). That is, the SOC of the battery is often managed by switching between energization and interruption of the battery by a relay. Then, the frequency of opening and closing of the relay becomes relatively high, and there is a possibility that deterioration of the relay progresses quickly.

  However, in the present invention, the priority is set for each battery by the priority setting means, and the required voltage for the battery with the highest priority set by the control means is set as the power generation voltage of the power generation means. As described above, the priority is set to be higher as the battery is more likely to be in an overcharged state or an overdischarged state.

  The required voltage related to the battery with the highest priority (in other words, a battery that is relatively likely to be in an overcharged state or an overdischarged state) is set as the generated voltage of the power generation means, thereby disconnecting the battery. In addition, the SOC of the battery can be appropriately controlled. As a result, since the switching frequency of the relay can be suppressed, the progress of the deterioration of the relay can be suppressed.

  As a result, according to the power management device of the present invention, it is possible to appropriately manage the SOC of the battery while suppressing the switching frequency of the relay.

  In one aspect of the power management device of the present invention, the two or more batteries include a lead storage battery and a nickel metal hydride battery or a lithium ion battery, and the priority setting means corresponds to the two or more batteries, An appropriate range of SOC of the nickel-metal hydride battery or lithium-ion battery in a map corresponding to the nickel-metal hydride battery or lithium-ion battery among the plurality of maps having a plurality of maps that define the relationship between the SOC and the priority The priority in the vicinity of the lower limit value is higher than the priority in the vicinity of the lower limit value of the appropriate SOC range of the lead storage battery in the map corresponding to the lead storage battery among the plurality of maps, and the nickel hydrogen battery or the lithium ion In the map corresponding to the battery, the priority in the vicinity of the upper limit value of the appropriate range of the SOC of the nickel metal hydride battery or the lithium ion battery is The nickel hydride battery or lithium ion battery in the map corresponding to the nickel hydride battery or lithium ion battery is higher than the priority in the vicinity of the upper limit value of the appropriate range of the SOC of the lead storage battery in the map corresponding to the lead acid battery. The priority of the central region of the appropriate range of the SOC is lower than the priority of the central region of the proper range of the SOC of the lead storage battery in the map corresponding to the lead storage battery.

  According to this aspect, the priority setting means has a map that defines the relationship between the SOC and the priority for each battery. If comprised in this way, it will be comparatively easy and the priority of each battery can be determined according to detected SOC, and it is very advantageous practically.

  In the present invention, in particular, the priority in the vicinity of the lower limit of the appropriate range of the SOC of the nickel metal hydride battery or lithium ion battery in the map corresponding to the nickel metal hydride battery or lithium ion battery is the priority of the lead acid battery in the map corresponding to the lead acid battery. It is higher than the priority in the vicinity of the lower limit value of the appropriate SOC range.

  If comprised in this way, when possibility that both a nickel metal hydride battery or a lithium ion battery and a lead acid battery will be in an overdischarge state increases, a comparatively expensive nickel metal hydride battery or a lithium ion battery is given priority. Since it is protected, it is very advantageous in practice.

  Moreover, the priority in the vicinity of the upper limit value of the SOC of the nickel metal hydride battery or the lithium ion battery in the map corresponding to the nickel metal hydride battery or the lithium ion battery is the upper limit of the appropriate range of the SOC of the lead acid battery in the map corresponding to the lead acid battery. It is higher than the priority in the vicinity of the value.

  If comprised in this way, when possibility that both a nickel metal hydride battery or a lithium ion battery and a lead acid battery will be in an overcharge state increases, a comparatively expensive nickel metal hydride battery or a lithium ion battery is given priority. Since it is protected, it is very advantageous in practice.

  Here, since the appropriate range of SOC differs for each battery, the SOC value corresponding to the lower limit value or upper limit value of the appropriate range of SOC of a nickel metal hydride battery or a lithium ion battery and the lower limit value of the proper range of SOC of a lead storage battery It should be noted that the SOC value corresponding to the upper limit value is different. In other words, it should be noted that the relationship is not a priority relationship when the SOC of the nickel metal hydride battery or the lithium ion battery is the same as the SOC of the lead storage battery.

  The “near the lower limit value” may mean a predetermined SOC range including the lower limit value, or may be lower than the center of the appropriate range (for example, the average value of the upper limit value and the lower limit value of the appropriate range). It may mean near SOC. Similarly, “near the upper limit value” may mean a predetermined SOC range including the upper limit value, or may mean an SOC closer to the upper limit value than the center of the appropriate range.

  On the other hand, in the map corresponding to the nickel metal hydride battery or lithium ion battery, the priority of the central area of the appropriate range of the SOC of the nickel metal hydride battery or lithium ion battery is the appropriateness of the SOC of the lead acid battery in the map corresponding to the lead acid battery. Lower than the priority of the center area of the range.

  If comprised in this way, in the SOC area | region where possibility of becoming an overcharge state or an overdischarge state is comparatively low, since the lead storage battery often used, for example as a main battery of a vehicle is protected preferentially, it is practical. Very advantageous.

  The “central area of the appropriate range” may mean a predetermined SOC range including the average value of the upper limit value and the lower limit value of the appropriate range, or the average value may be higher than the upper limit value or the lower limit value of the appropriate range. May mean an SOC close to.

  The effect | action and other gain of this invention are clarified from the form for implementing demonstrated below.

It is a schematic structure figure showing an outline of a power management device concerning an embodiment. It is a flowchart which shows the power management process which concerns on embodiment. It is a specific example of the map which prescribes | regulates the relationship between SOC and a priority.

  An embodiment according to a power management apparatus of the present invention will be described with reference to the drawings.

(Configuration of power management device)
The configuration of the power management apparatus according to the embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram illustrating an overview of a power management apparatus according to the embodiment. In addition, in FIG. 1, illustration is abbreviate | omitted suitably about the member which is not related to this embodiment.

  In FIG. 1, the vehicle on which the power management device 100 is mounted includes a generator 11, a first power system 12, a second power system 13, and a third power system 14.

  Here, the first power supply system 12 has almost no influence on the operation even if a large instantaneous fluctuation of power occurs, such as a voltage drop caused by the operation of a starter motor (not shown). This is a system that supplies power to a load that is not present (see “auxiliary load 1” in FIG. 1). The relay of the first power supply system 12 (see “1st relay” in FIG. 1) switches between energization and disconnection between the generator 11 and the battery 15.

  The second power supply system 13 is a system that supplies electric power to a load that is affected by a large fluctuation of electric power or a load that requires power supply backup (see “auxiliary load 2” in FIG. 1). . The relay of the second power supply system 13 (see “2nd relay” in FIG. 1) switches between energization and interruption of the generator 11 and the battery 16.

  The third power supply system 14 is a system including, for example, a battery 17 and a load (see “auxiliary load 3” in FIG. 1) used for improving the regeneration efficiency of electric power and improving fuel consumption. The relay of the third power supply system 14 (see “3rd relay” in FIG. 1) switches between energization and interruption of the generator 11 and the battery 17.

  Each relay is appropriately opened and closed according to the SOC of each of the batteries 15, 16 and 17 and the operating state of the auxiliary load. In addition, since various well-known aspects are applicable to control of each relay, the description about the detail is omitted.

  In the present embodiment, the battery 15 is, for example, a lead storage battery, and the battery 16 is, for example, a nickel metal hydride battery or a lithium ion battery. The power supply system may be only the first power supply system 12 and the second power supply system 13, or may include four or more power supply systems.

  The power management apparatus 100 according to the present embodiment includes an ECU (Electronic Control Unit) 20. That is, in the present embodiment, a part of the function of the ECU 20 used for various electronic controls of the vehicle is used as a part of the power management apparatus 100.

(Power management process)
Next, the power management process performed by the power management apparatus 100 while the vehicle is traveling will be described with reference to the flowchart of FIG.

  In FIG. 2, first, the ECU 20 as a part of the power management apparatus 100 calculates (detects) the SOC of each of the batteries 15, 16 and 17 (step S101). Since various known modes can be applied to the SOC calculation method, a detailed description thereof will be omitted.

  Next, ECU20 determines the priority which concerns on charging / discharging of each of batteries 15, 16, and 17 based on SOC of each of batteries 15, 16, and 17 (step S102).

  Here, the priority determination method will be described with reference to FIG. In FIG. 3, “upper limit” and “lower limit” mean “upper limit value” and “lower limit value” of an appropriate SOC range (hereinafter referred to as “appropriate SOC range” as appropriate). In FIG. 3, “center” means “center (that is, an average value of the upper limit value and the lower limit value of the appropriate SOC range)” of the appropriate SOC range. Also, the scale of the vertical axis (ie, “priority”) of each map in FIG. 3 is the same.

  The ECU 20 stores in advance a plurality of maps (see FIG. 3) that correspond to the batteries 15, 16 and 17, respectively, and define the relationship between the SOC and the priority. The relationship (that is, the map) between the SOC and the priority is determined by, for example, the type of battery and / or the power supply system to which the battery is electrically connected.

  Specifically, for example, in the case of a battery having a relatively wide SOC that can be used regularly, the priority does not change within a certain range from the center value of the appropriate SOC range, as shown in FIG. This is a map in which the priority increases in the vicinity of the upper limit value and the lower limit value of the appropriate SOC range. If comprised in this way, it can suppress at least that a battery will be in an overdischarge state and an overcharge state.

  Alternatively, in the case of a battery that needs to avoid low SOC in order to function as a backup power supply (that is, a battery used in the second power supply system 13) or a battery that is relatively vulnerable to overdischarge, FIG. As the SOC approaches the lower limit from the center value of the appropriate SOC range, the priority is rapidly increased. Note that the degree of increase in priority (that is, the slope) may be set depending on how much low SOC can be tolerated. If comprised in this way, it can prevent that a battery will be in low SOC or an overdischarge state.

  When measures such as gas generation countermeasures are taken on the vehicle side against overcharge of the battery, the SOC is slightly higher from the center value of the appropriate SOC range to the upper limit side as shown in FIG. Even if it changes, a map whose priority does not change may be applied.

  In this embodiment, the map shown in FIG. 3A is set to the map of the lead storage battery as the battery 15, and the map shown in FIG. 3B is a nickel metal hydride battery or a lithium ion battery as the battery 16. It is assumed that it is set in the map. In this case, the upper limit value and the lower limit value of the SOC in the map of FIG. 3A are, for example, 100% and 90%, respectively. The upper limit value and lower limit value of the SOC in the map of FIG. 3B are, for example, 70% and 30%, respectively.

  Based on the SOC of each of the batteries 15, 16 and 17, the ECU 20 determines the priority of each of the batteries 15, 16 and 17 from the map corresponding to each of the batteries 15, 16 and 17.

  Returning to FIG. 2 again, the ECU 20 sets a required voltage related to the battery having the highest priority among the batteries 15, 16 and 17 (step S103). The “required voltage” is determined by the characteristics of the battery having the highest priority (for example, a characteristic curve indicating the relationship between the SOC and the open circuit voltage, the SOC at the time when the priority is determined, etc.). Since various known modes can be applied to the method for setting the required voltage, a detailed description thereof is omitted.

  When the vehicle is not decelerating, it is desirable from the viewpoint of improving fuel efficiency that the required voltage is set lower than the terminal voltage of the battery. When the SOC of the battery with the highest priority is close to the lower limit value of the appropriate SOC range and the priority of the battery is high, the required voltage is a voltage that does not discharge the battery with the highest priority, The voltage may be lower than the terminal voltage of other batteries. If comprised in this way, both protection of the battery with the highest priority and improvement in fuel consumption can be achieved.

  Next, the ECU 20 determines whether or not the power supply system of the vehicle is normal, and whether or not the SOC of each of the batteries 15, 16 and 17 is within the corresponding appropriate SOC range (step S104). ).

  When it is determined that the power supply system of the vehicle is normal and the SOC of each of the batteries 15, 16 and 17 is within the corresponding appropriate SOC range (step S104: Yes), the ECU 20 is decelerating the vehicle. Whether or not (step S105).

  When it is determined that the vehicle is decelerating (step S105: Yes), the ECU 20 sets the power generation voltage of the generator 11 to the required voltage during regeneration (step S106). The “required voltage during regeneration” is a voltage higher than the terminal voltages of all the batteries that are electrically connected to the generator 11 via a relay.

  On the other hand, when it is determined that the vehicle is not decelerating (step S105: No), the ECU 20 sets the generated voltage of the generator 11 to the required voltage related to the battery with the highest priority set in the process of step S103. (Step S107).

  With this configuration, the power generation voltage is suitable for the battery having the highest priority (in other words, to be protected with the highest priority). Therefore, the battery is disconnected from the generator 11 by a relay, for example. It is possible to appropriately perform SOC management.

  Specifically, for example, when the SOC of the battery with the highest priority is near the lower limit value of the appropriate SOC range (that is, when there is a high possibility of being in an overdischarge state), the battery with the highest priority is Since the generated voltage is not discharged or charged, the relay connected to the battery can be prevented from being opened due to the battery being overdischarged.

  Alternatively, when the SOC of the battery with the highest priority is near the upper limit value of the appropriate SOC range (that is, when there is a high possibility of being in an overcharge state), the battery with the highest priority is not charged any more or Since the generated voltage is discharged, it is possible to prevent the relay connected to the battery from being opened due to the battery being overcharged.

  As a result, the frequency of opening and closing of the relay can be reduced, and the deterioration of the relay can be suppressed. In addition, since the frequency of opening and closing of the relay is relatively low, for example, a mechanical relay can be employed instead of a relatively expensive semiconductor relay, and the manufacturing cost can be reduced, for example.

  Particularly in the present embodiment, the priority of the lower limit value of the SOC of the map corresponding to the battery 16 (see FIG. 3B) is the lower limit value of the SOC of the map corresponding to the battery 15 (see FIG. 3A). Be higher than priority. For this reason, when the possibility that the nickel hydride battery or the lithium ion battery as the battery 16 is in an overdischarged state is relatively high, the possibility that the lead storage battery as the battery 15 is in an overdischarged state is relatively high Even so, it will be preferentially protected.

  Further, the priority of the upper limit value of the SOC in the map corresponding to the battery 16 (see FIG. 3B) is higher than the priority of the upper limit value of the SOC in the map corresponding to the battery 15 (see FIG. 3A). Get higher. For this reason, when the nickel hydride battery or the lithium ion battery as the battery 16 is relatively highly likely to be in an overcharged state, the lead storage battery as the battery 15 is relatively likely to be in an overcharged state. Even preferential protection.

  That is, in this embodiment, it is possible to reliably prevent a nickel-metal hydride battery or a lithium ion battery that is more expensive than a lead storage battery from being overdischarged or overcharged. For this reason, for example, deterioration of a nickel metal hydride battery or a lithium ion battery can be suppressed, which is very advantageous in practice.

  On the other hand, the priority of the central region of the SOC of the map corresponding to the battery 15 (see FIG. 3A) is higher than the priority of the central region of the SOC of the map corresponding to the battery 16 (see FIG. 3B). Is also expensive. For this reason, when all of the batteries 15, 16 and 17 are relatively unlikely to be in an overcharged state or an overdischarged state, the lead storage battery as the battery 15 is preferentially protected.

  In the process of step S104 described above, there is an abnormality in the power supply system of the vehicle, or the SOC of at least one of the batteries 15, 16, and 17 is out of the appropriate SOC range corresponding to the battery (ie, When it is determined that the battery is in an overcharged state or an overdischarged state (step S104: No), the ECU 20 sets the power generation voltage of the generator 11 to a predetermined voltage required when the power supply system is abnormal, or Then, the required voltage is set according to the battery in the overcharged state or the overdischarged state (step S108).

  It should be noted that various known modes can be applied to the required voltage when the power supply system is abnormal and the required voltage setting method according to the overcharged or overdischarged battery. Will be omitted.

  The “ECU 20” according to the embodiment is an example of the “detection unit”, the “priority setting unit”, and the “control unit” according to the present invention. “Batteries 15, 16 and 17” according to the embodiment are examples of “two or more batteries” according to the present invention. The “generator 11” according to the embodiment is an example of the “power generation means” according to the present invention.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. Is also included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 11 ... Generator, 12 ... 1st power supply system, 13 ... 2nd power supply system, 14 ... 3rd power supply system, 15, 16, 17 ... Battery, 20 ... ECU, 100 ... Power supply management apparatus

Claims (2)

A power management device for a vehicle comprising two or more batteries, power generation means, and a plurality of relays corresponding to the two or more batteries and switching between energization and interruption of the corresponding batteries and the power generation means,
Detecting means for detecting SOC relating to each of the two or more batteries;
Priority setting means for setting the priority of charge / discharge of each of the two or more batteries based on the detected SOC;
Control means for setting, as a power generation voltage of the power generation means, a required voltage related to the battery having the highest priority set when the vehicle is not decelerated;
With
The priority setting means, for each of the two or more batteries, as the detected SOC approaches the upper limit value of the appropriate range of SOC predetermined for each of the two or more batteries, or approaches the lower limit value, The power management apparatus characterized in that the priority is set high. The two or more batteries include a lead storage battery and a nickel metal hydride battery or a lithium ion battery,
The priority setting means corresponds to each of the two or more batteries, and has a plurality of maps that define the relationship between the SOC and the priority,
In the map corresponding to the nickel metal hydride battery or lithium ion battery among the plurality of maps, the priority in the vicinity of the lower limit value of the appropriate range of the SOC of the nickel metal hydride battery or lithium ion battery is the lead among the plurality of maps. Higher than the priority near the lower limit of the appropriate range of the SOC of the lead storage battery in the map corresponding to the storage battery,
In the map corresponding to the nickel metal hydride battery or lithium ion battery, the priority in the vicinity of the upper limit of the appropriate range of the SOC of the nickel metal hydride battery or lithium ion battery is the SOC of the lead acid battery in the map corresponding to the lead acid battery. Higher than the priority near the upper limit of the appropriate range of
In the map corresponding to the nickel metal hydride battery or lithium ion battery, the priority of the central region of the appropriate range of the SOC of the nickel metal hydride battery or lithium ion battery is the SOC of the lead acid battery in the map corresponding to the lead acid battery. The power management apparatus according to claim 1, wherein the power management apparatus is lower than the priority of the central area of the appropriate range.

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