JP2001128385A - Power supply system for motor vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply system for motor vehicle, capable of ensuring a prescribed charging capacity, even for a battery having accelerating deterioration. SOLUTION: This power supply system 21 for motor vehicle is provided with a charging battery 107, a charger 12 for charging the charging battery 102, and a battery control device 105 controlling battery conditions, including the remaining capacity of the battery, where the battery control device 105 changes charging stop conditions based on the battery conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric bicycle, an electric wheelchair, an electric scooter, and the like, which can secure a charging capacity of a rechargeable secondary battery such as Ni-Cd or Ni-MH used as an energy source. To a power supply system for an electric vehicle.

[0002]

2. Description of the Related Art When charging a secondary battery, a charging stop condition is set in advance as a fixed value regardless of whether the battery is new or old or in a deteriorated state, and charging is stopped when the battery reaches the set value during charging. This is the conventional general charge control. The charge stop conditions include dT / dt, -ΔV, Tco, a total timer value, a temperature rise absolute value, and the like. The above d
T / dt is the rate of change (temperature rise rate) of the battery temperature with respect to the charging time, -ΔV is the voltage drop from the maximum voltage of the battery,
Tco indicates the charging stop temperature of the battery, and when these values reach the values set as the charging stop conditions, the charging is stopped.

In a nickel-metal hydride battery, it is necessary to stop charging in a state where the depth of charge is shallow in order to secure the life performance.
/ Dt) is generally selected.

[0004]

However, when charging is an exothermic reaction as in the case of a nickel-metal hydride battery, there is no problem when the battery is in a new state, but when the battery is deteriorated and the internal resistance is increased, the charging depth is reduced. Irrespective of this, the temperature rise rate increases. Therefore, when the battery deteriorates, the temperature rise rate reaches the charge stop temperature rise rate set as the charge stop condition before the battery is sufficiently charged, and the charge is stopped. In order to avoid this premature stop of charging, it is sufficient to set the charge stop temperature rise rate to a large value. However, in such a case, a new battery is overcharged and adversely affects the battery life. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and has as its object to provide a power supply system for an electric vehicle that can secure a predetermined charge capacity even with a deteriorated battery. .

[0006]

According to a first aspect of the present invention, there is provided an electric motor comprising a rechargeable battery, charging means for charging the battery, and a battery management device for managing a battery state including a remaining capacity of the battery. In the vehicle power supply system, the battery management device changes a charging stop condition based on a battery state.

[0007] A second aspect of the present invention is characterized in that, in the first aspect, the battery management device changes the charging stop condition according to a change in the actual capacity of the battery.

A third aspect of the present invention is characterized in that, in the second aspect, the battery management device changes the charging stop condition such that the smaller the ratio of the actual capacity to the initial capacity becomes, the deeper the charging depth becomes.

According to a fourth aspect of the present invention, the battery management device according to the second or third aspect, wherein the battery management device discharges the battery during traveling until the battery voltage reaches a preset capability capacity determination voltage value, or The refresh discharge capacity discharged before the battery voltage reaches the set voltage value during the refresh discharge, or the sum of the running discharge capacity and the refresh discharge capacity is defined as the actual capacity, and the charge stop condition is determined based on the actual capacity. Is changed.

According to a fifth aspect of the present invention, in the first aspect, the battery management device determines a condition for stopping charging when the degree of battery deterioration obtained from the current I-voltage V characteristic curve of the battery is large. It is characterized in that the charging depth is changed so as to be deeper than the charging stop condition in the case of.

According to a sixth aspect of the present invention, in the second aspect, when the actual capacity or the battery deterioration degree after the change of the charging stop condition is restored to a predetermined threshold value or more, the charging stop condition is restored. It is characterized by:

According to a seventh aspect of the present invention, in the sixth aspect, if the actual capacity or the battery deterioration level falls below a predetermined threshold value again after the charging stop condition is restored, the charging stop condition is changed again, and It is characterized in that the changed charging stop condition is fixed.

According to an eighth aspect of the present invention, in the first aspect of the present invention, the battery management device includes a charging stop condition when the degree of battery deterioration obtained from the battery history (the number of times of charging, the number of times of discharging, the number of times of charging / discharging, etc.) Is changed so that the charging depth is deeper than the charging stop condition when the battery deterioration degree is small.

In the present invention, the state of the battery mainly means the degree of deterioration of the battery. The degree of deterioration of the battery is, for example, smaller as the actual capacity (refreshable starting discharge capacity, running starting actual capacity) is smaller. If the current I-voltage V characteristic of the battery is smaller than a threshold value set for each battery temperature for each remaining battery capacity, it is determined that the degree of deterioration is progressing. As the number of times of charging, the number of times of discharging, and the number of charging / discharging cycles are larger, it is determined that the degree of deterioration is advanced.

[0015] The "refreshing start-up capability" means that the vehicle ends running without sufficiently discharging the battery until the voltage drops to the discharge stop voltage (not running out).
It means the total discharge capacity when a predetermined voltage value is discharged (completely discharged) in the subsequent refresh discharge. Therefore, “starting out” is not necessarily limited to completely starting out. Further, the "starting-time running capacity" means the running-time discharging capacity discharged until the battery voltage reaches a predetermined capacity-capacity determination voltage value by running.

The term "charging stop condition" in the present invention mainly means a rate at which the temperature at which charging is stopped rises. Further, setting the condition at which charging is stopped so as to increase the depth of charge means, for example, setting a rate at which the temperature at which charging stops rises is set large. Is the meaning of

[0017]

According to the first aspect of the invention, the charging stop condition is changed based on the state of the battery, for example, by changing the actual capacity as in the second aspect of the invention.
The required charge capacity can be secured even if the battery state changes. Specifically, as in the third aspect of the present invention, the charging stop condition is changed so that the charging depth becomes deeper as the ratio of the actual capacity to the initial capacity becomes smaller. In the case of a used battery, the charging stop temperature rise rate is set to be large, and a required charging capacity can be secured. In the case of a new battery having a large capacity, that is, a battery that has not deteriorated, the charging stop temperature rise rate is set to be small, thereby preventing overcharging.

According to the fourth aspect of the present invention, the actual capacity is determined as a running discharge capacity or a refreshing discharge capacity.
Alternatively, since the running discharge capacity and the refreshing discharge capacity are summed, by changing the charging stop condition based on the actual capacity, it becomes possible to obtain a charging depth corresponding to the degree of deterioration of the battery. Even in the case of a battery that has advanced, a required charging capacity can be secured, and overcharging of a battery that has not progressed can be prevented.

According to the fifth aspect of the present invention, the charging is stopped when the degree of battery deterioration obtained from the IV characteristic curve of the battery is large, and according to the eighth aspect of the present invention, the charging is stopped when the degree of battery deterioration obtained from the battery history is large. Since the condition is changed so that the depth of charge is deeper than the condition for stopping charging when the degree of battery deterioration is small, a required charge capacity can be ensured even for a battery with a high degree of deterioration.

According to the sixth aspect of the present invention, the charge stop condition is restored when the actual capacity or the battery deterioration degree after the change of the charge stop condition is restored to a predetermined threshold value or more. For a battery that may become overcharged due to the change of the above, the original charge stop condition can be returned, and overcharge can be avoided.

According to the seventh aspect of the present invention, when the actual capacity or the degree of battery deterioration falls below the predetermined threshold value again after the charging stop condition is restored, the charging stop condition is changed and fixed again. In addition, it is possible to stabilize the charging condition by preventing hunting when the actual capacity is close to the threshold value, and to prevent fluctuation due to erroneous detection.

[0022]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 16 are views for explaining a power supply system for an electric assisted bicycle according to an embodiment of the present invention. FIG. 1 shows a case where the charging device is not mounted on the vehicle and the detachable battery case is mounted on the vehicle. FIG. 2 is a block diagram of the power supply system, and FIGS. 3 to 5 illustrate signal data transmitted and received between a battery management device and a charging device of the power supply system. 6 to 12 are flowcharts for explaining the operations of the battery management device and the charging device, and FIGS. 13 and 14 are characteristic diagrams for explaining the charging stop condition. FIGS. 15 and 16 are diagrams showing a method for obtaining another charging stop condition.

In the figure, reference numeral 1 denotes an electric assisted bicycle as an electric vehicle in which the charging device 112 is not mounted on the vehicle and a detachable battery case 100 is mounted on the vehicle in the power supply system according to the present embodiment. A down tube 4 extending obliquely downward from the head pipe 3 toward the rear of the vehicle body; a seat tube 5 extending substantially upright from a rear end of the down tube 4; A pair of left and right chain stays 6 extending to the left and right, a pair of left and right seat stays 7 connecting the rear ends of the two chain stays 6 and the upper end of the seat tube 5, the head pipe 3 and the seat tube 5 and a top tube 11 for connecting to the top tube 5.

A front fork 8 is pivotally supported on the head pipe 3 so as to be rotatable left and right. A front wheel 9 is pivotally supported at the lower end of the front fork 8, and a steering handle 10 is fixed at the upper end. A saddle 12 is attached to the upper end of the seat tube 5. Further, a rear wheel (wheel) 13 is supported at the rear end of the chain stay 6.

Although not shown, an instrument panel (not shown) provided with a speed meter and the like is provided at the center of the steering handle 10, and it is determined that refresh discharge is necessary in this panel portion. A display device may be provided for displaying the fact when the display is completed.

At the lower end of the vehicle body frame 2, a pedaling force (manpower) input to a pedal 16 b via a crank arm 16 a attached to a projecting portion of the crankshaft 16 at both ends, and a power from a built-in electric motor 17. A power unit 15 for outputting a resultant force with auxiliary power proportional to the magnitude of human power is mounted. That is, the magnitude of the pedal effort becomes the motor drive command 28. The output from the power unit 15 is transmitted to the rear wheel 13 via the chain 30.

The bicycle 1 of this embodiment also has a self-propelled lever 14 for inputting a motor drive command 28 from the outside. By operating the self-propelled lever 14, the bicycle 1 does not need to input to the pedal 16b. It is also possible to run only with the power from the electric motor 17.

The battery case 100 serving as a power source for the electric motor 17 and the like is detachably attached to the vehicle body along the rear surface of the seat tube 5 and sandwiched between the left and right seat stays 7,7. It is arranged. The battery case 100 houses a battery (rechargeable battery) 102 formed by connecting a number of unit cells 101 in series. The battery case 100 also includes a temperature sensor 103 for detecting the temperature of the battery 102, and a current of the battery 102. And an ammeter 104 for measuring a value. Furthermore, the battery case 100 includes the battery 1
And a battery management device 105 for performing management and the like of the storage device 02.

When mounted on the vehicle, the battery case 100 is automatically connected to the motor drive circuit 22 by the connectors 107 and 108 at the same time as the battery case 100 is mounted. Automatic connection is established via communication I / Fs 120a and 120b.

On the other hand, at the time of charging, the battery case 100 is connected to the output side of a non-vehicle completely independent charging device 112 by connectors 113 and 114 while being detached from the vehicle body or in a vehicle-mounted state. In addition, they are connected by the connectors 115 and 116 via the communication I / Fs 127 and 120c of the charging device 112. In FIG. 1, reference numeral 100a denotes a charging port provided in the battery case 100.
4, 115, 116 battery case side terminals are arranged.
Reference numeral 121 denotes a charging plug of the charging device 112,
The charging device side terminals of the connectors 113 to 116 are arranged therein, and can be freely inserted into the charging port 100a. The battery case 100 and the charging device 112
Thus, the power supply system 21 according to the present embodiment is configured. The connectors 107, 108 and 113, 11
4, and the connectors 110, 111 and 115, 116 may be common.

The battery management device 105 receives the battery temperature data T from the temperature sensor 103, the current value data I from the ammeter 104, and the voltage data V of the battery 102, and A battery management / control unit 117 for controlling refresh discharge and the like and an EEPROM 106 for storing predetermined data are provided. A display button 118 is provided when display is required based on a signal from the battery management / control unit 117. The display device 119 displays the remaining battery capacity and refresh information by pressing.
And communication I / Fs 120c and 120a for communicating with the charging device 112 and the travel control unit 109.
Note that the display device 119 may be provided on a display panel portion on the vehicle side where a speed meter or the like is installed.

The EEPROM 106 stores, as the predetermined data, the number of charges, the number of discharges, the number of charge / discharge cycles since the initial or previous refresh discharge, and the like.
The initial capacity of the battery 102, the actual capacity of the battery, the discharge capacity during running, the discharge capacity during refresh, the presence / absence of execution of refresh discharge after refresh display, and the like are stored.

The battery management / control section 117 controls the battery status of the rechargeable battery 102, for example, battery temperature, voltage, remaining capacity, etc., the number of times of charge, the number of times of discharge since the initial or previous refresh discharge, the number of times of charge and discharge. The necessity of the refresh discharge is determined based on the number of cycles, the difference between the actual capacity of the battery and the discharge capacity, the history of the battery such as whether or not the refresh discharge is performed after the refresh display, and the like. It functions to display on the display device 119.

Further, the battery management / control unit 117
In refresh discharge, the capacity of the battery 102 is determined based on the sum of the discharge capacity during running before refresh discharge and the discharge capacity during refresh by refresh discharge. The battery 102 functions as a capacity determining means for determining the running capacity of the battery 102 based on the set capacity capacity determination voltage value, for example, the running capacity discharged before the battery 102 drops to the discharge stop voltage. It also functions as a battery deterioration degree determining unit that compares the actual capacity and the initial capacity to determine the deterioration degree of the battery 102.

The above-mentioned actual capacity is obtained only when the following conditions are satisfied, whereby the actual capacity (actual capacity) of the battery is accurately obtained. That is, the charge / discharge cycle counter is 20 or less, the charge before discharge is completed normally, that is, the charge is stopped before the predetermined charge completion determination is made for some reason that occurred during the charge. No capacity, measured self-discharge capacity is equal to or less than a predetermined value, and battery temperature at the end of discharge is within a predetermined range. The decision on capacity is forgotten.

As the discharge capacity during refresh, the discharge capacity up to the end of the first-stage discharge in a two-stage refresh discharge described later is used.

In the present embodiment, the battery management / control unit 117 functions as a charge control unit to
As shown in FIG. 3, it is considered that the deterioration of the battery is progressing as the ratio (%) of the refresh start start ability capacity or the running start start ability capacity to the battery initial capacity becomes smaller, and the charge stop condition is set so as to increase the depth of charge. change. That is, as the ratio of the battery decreases, that is, as the degree of deterioration increases, the charge stop temperature rise rate (dT / d
Change t) to a larger value.

Specifically, as shown in FIG. 13, the method of changing the rate of increase of the charge stop temperature is as shown in FIG. Various methods can be adopted, such as changing the ratio continuously so as to increase the ratio (characteristic line A), switching to four stages (characteristic line B), or switching to two stages (characteristic line C). For example, when the characteristic line C is adopted, the charging stop temperature rise rate is:
When the above ratio is 25% or more, C1 is adopted, and when it is less than 25%, C2 is adopted.

The reason why the charging stop temperature rise rate is changed according to the degree of battery deterioration will be described with reference to FIG. FIG.
As shown in FIG. 4, in the case of a new battery (non-deteriorated battery), the temperature rise curve during charging is relatively gentle, and when the charging time has sufficiently passed, that is, when the charging capacity has been sufficiently ensured. The temperature rise rate dT / dt reaches the charge stop temperature rise rate. On the other hand, in the case of a long-life battery (deteriorated battery), the temperature rise curve during charging is relatively steep, so that the temperature rise rate dT / dt is the charging stop temperature rise rate. Therefore, the rate of increase in the temperature at which the charge of the deteriorated battery is stopped is set to be larger than the rate of increase of the temperature at which the non-deteriorated battery stops charging.

The charging device 112 includes an AC / DC converter 124 for converting AC power supplied by connecting the plug 123 to an outlet, and a voltage for measuring a voltage value and a current value of an output of the converter 124. Total 1
25, an ammeter 126, a discharger (discharging means) 135 for performing a refresh discharge of the rechargeable battery 102, measurement values from the voltmeter 125, the ammeter 126, and the communication I
/ F127 and a charge / discharge control unit 128 to which a predetermined signal or the like is input.

The charging device 112 includes a battery connection detecting unit 129 that outputs a connection signal indicating that the charging device 112 and the battery case 100 are connected to the charging / discharging control unit 128. ing.

Further, in the charging device 112, a display indicating that a refresh is being performed is displayed on a display device 133, which will be described later, and when a refresh discharge is started, the charge refresh cancel switch 131 cancels the refresh discharge and shifts to a charging mode. Is provided.

The output of the AC / DC converter 124 is supplied to the charge / discharge control unit 128 via the output control unit 132.
Is controlled by Also, the display device 133 or the discharger 1
35 is controlled by the charge / discharge control unit (discharge control means) 128. The display device 133 displays information such as charging standby, charging, charging completed, charging stopped, refreshing, refresh end, and the like.

Next, based on FIGS. 3 to 5, the battery management device 105 and the charging device 11 in the electric assist bicycle 1 will be described.
2 will be described.
3 to 5 show signal data numbers (No),
And the contents of the number.

FIG. 3 shows charge / discharge control data collectively transmitted from the battery management device 105 to the charging device 112.
2 is a “first-stage refresh discharge current value”, 3 is a “first-stage refresh pulse value”, 4 is a “first-stage refresh discharge stop voltage”, and 5 is a “second-stage refresh discharge current value”. , 6 is the “second-stage refresh discharge stop voltage”, 7 is the “refresh timer value”, 8 is the “charge start lower limit temperature”, 9 is the “charge start upper limit temperature”, and 10 is the “charge current value”. “I” further includes “battery temperature rise rate (dT / dt) as a charging stop condition” as 11. The “refresh discharge execution request” is specifically “Yes”
Alternatively, "absence" is indicated, and functions as a signal for notifying whether or not to execute the refresh discharge.

FIG. 4 shows the battery state data transmitted collectively from the battery management device 105 to the charging device 112, where 1 is "battery temperature (1)" and 2 is "battery temperature (2)". However, 3 includes “battery voltage”, 4 includes “current battery remaining capacity”, and 5 includes “battery capacity, that is, the maximum capacity learning value at the current time”. The maximum capacity learning value refers to the maximum capacity value at the current point in time as the battery gradually deteriorates as charging and discharging are repeated and the maximum capacity also changes (decreases) gradually. More specifically, as will be described later, it is obtained based on the sum of the running discharge capacity before the refresh discharge and the refresh discharge capacity by the refresh discharge. It includes the refresh start-up ability capacity and the run-out start ability capacity obtained from the running discharge capacity discharged before the battery voltage drops to the discharge stop voltage during running.

As shown in FIG. 2, the battery temperature (1) is the battery temperature of a configuration including one set of the rechargeable batteries 102, and the battery temperature (2) is the second temperature of a configuration including two rechargeable batteries. , Respectively. When a plurality of rechargeable batteries 102 are provided, the battery temperature (1) to
(N).

FIG. 5 shows the charger status data transmitted from the charging device 112 to the battery management device 105 collectively, where 1 is “charge / discharge control data request” and 2 is “battery status data request”. As 3, "1st stage refreshing" and 4 as "1st stage refresh end"
5 is “second stage refreshing”, 6 is “second stage refresh end”, 7 is “charging”
However, 8 is “charging standby” and 9 is “charging completed”
However, “10” includes “stop charging”. Note that "charging completed" means that the battery has been charged 100%, and "charging stopped" means that charging has been stopped because it is dangerous to continue charging further.

Next, based on the flowcharts of FIGS. 6 to 12, the battery management device 1 in the power supply system 21 will be described.
05 and the operation of the charging device 112 will be described. Figures 6 and 10
12 to 12 show the operation of the battery management device 105 in FIGS.
Indicates the operation of the charging device 112, respectively.

First, the refresh processing of the battery management device will be described with reference to FIG. The battery management device 105 is in the standby mode (step C1), and a charger connection signal is detected by interruption of a connection signal (D9) described later (step C2), and FIG.
When the "charge / discharge control data request" signal shown in No. 1 is received (step C3), the battery management device 105 determines whether or not the refresh discharge is necessary (step C4), and creates the charge / discharge control data (step C4). C5) The charge / discharge control data shown in FIG. 3 is transmitted from the battery management device 105 to the charging device 112 (step C6).

The necessity of the refresh discharge in step C4 is determined by the number of charges, the number of discharges, or the number of charge / discharge cycles from the initial or previous refresh discharge, or the refresh after the previous "refreshing" display. This is performed based on whether or not discharge has been performed. For example, when the number of charge / discharge cycles is 20 or more, and when the refresh release switch 131 is turned on after the previous “refreshing” display and the refresh discharge is not completed to the end, it is determined that the refresh discharge is necessary. You.

Next, the reception of the "charger status data" signal of FIG. 5 is awaited (step C7), and when this signal is normally received (step C8), "refreshing" is included in the charger status data. Is determined (step C9). If the battery is being refreshed, the battery temperature, voltage, and current are measured (step C10), and the remaining capacity of the battery is calculated (step C11). 4 is transmitted to the charging device 112 (step C12).

Then, the charging device 112 is connected to the battery management device 105 (step C13), and the current refresh discharge is not at the second stage (step C1).
4) When the first-stage refresh discharge is completed (Step C15), the running discharge capacity before the refresh discharge and 1
The total discharge capacity with the discharge capacity at the time of the refresh by the second-stage refresh discharge is temporarily adopted as the refresh start-out capability, and the provisional refresh start-up capability is further determined as shown in FIG. 11B (step C16). .

The refresh starting capacity is shown in FIG.
As shown in (b), when the cycle counter is 20 or less, the previous charge of the rechargeable battery 102 has been completed normally, the self-discharge amount is less than a predetermined set value, and the first stage If the battery temperature at the end of the discharge is within a predetermined range, it is determined as the refresh start starting capability (steps A1 'to A5'). Step A
If at least one of the determination conditions of 1 'to A4' is missing, the determination of the refresh start-out capability is postponed (step A6 ').

Either the refresh start-up capacity determined in FIG. 11B or the running start-up capacity determined in FIG. 11A is the battery capacity.

Then, in step C26 following step C16, the charging stop temperature rise rate (dT / dt) is set. This is performed based on the temperature rise rate setting flow shown in FIG. A case where the characteristic line C of FIG. 13 is employed will be described. It is determined whether or not the actual capacity is determined (step G10), and if it is determined, whether it is the refresh start actual capacity or the running start actual capacity (step G10 '), the determined actual capacity with respect to the initial capacity is determined. If the ratio is not less than the determination threshold (25%) and the number of temperature rise rate changes is not more than the set value (two in the case of the present embodiment),
The process ends with the temperature rise rate dT / dt remaining unchanged at the initial value (C1) (steps G11 to G14).

On the other hand, when the ratio of the actual capacity to the initial capacity is smaller than the threshold value in steps G11 and G12, or when the number of changes in the temperature rise rate is equal to or more than the set value (two times) in step G13. Is changed to a change value C2 larger than the initial value C1 and the number of changes is set to 1 (steps G15 and G16), and the process ends. It should be noted that it is of course possible to set the temperature rise rate based on the capacity of the refresh start only by the refresh discharge. If the actual capacity has not been determined, the process ends.

In the subsequent and subsequent flows, if for some reason the ratio of the refresh start actual capacity or the running start actual capacity to the initial capacity becomes larger than the threshold value in steps G11 and G12, the temperature rise rate change number is determined in step G3. Is 1 and is smaller than the set value 2, so that the charging stop temperature rise rate is returned to the initial value C1.

When the actual capacity or the like returns to the non-degraded state of the battery after the charging stop temperature rise rate is changed to the large value C2 as described above, the charge stop temperature rise rate is returned to the original value C1. Therefore, the problem of overcharging the non-deteriorated battery can be avoided.

On the other hand, the charging stop temperature rise rate is set to an initial value C
After returning to 1, if the ratio becomes smaller than the threshold value again in steps G11 and G12 in the subsequent flow, the charging stop temperature rise rate is changed again to the change value C2,
The number of changes in the temperature rise value is two (steps G15 and G1).
6). Even if the ratio becomes larger than the threshold value again in the subsequent flow, in step G13, the number of changes in the temperature increase rate is 2 and the set value is 2 or more. Fixed to

As described above, the rate of increase in the temperature at which the charging is stopped is calculated using the original value C.
If the discharge capacity falls below the threshold value again after returning to 1, the charge stop temperature rise rate is changed again to C2 and fixed, so that hunting when the discharge capacity is near the threshold value is prevented and the charging conditions are stabilized. And fluctuation due to erroneous detection can be prevented.

Here, as a method for setting the above-mentioned charging stop temperature rise rate, the methods shown in FIGS. 15 and 16 can be adopted. FIGS. 16A and 16B show that the remaining battery capacity is 90 to 10%.
It is a current I-voltage V characteristic diagram for each battery temperature in the case of 0% and 60-70%. For example, when the remaining battery capacity is 90 to 100% and the battery temperature is 40 ° C., the IV characteristic is 20 A to 26 V.
In the case of (point a), the battery is a non-deteriorated battery, and 20A-20V
In the case of (point b), it is determined that the battery is a deteriorated battery.

In FIG. 15, if the IV characteristic is not smaller than a predetermined threshold value (for example, a line at T = 40 ° C.) (point a in FIG. 16) and the number of temperature rise rate changes is not more than the set value 2, , The temperature rise rate remains at the initial value (C1 in FIG. 13) and is not changed (steps H1 to H3).

On the other hand, if the IV characteristic is smaller than the predetermined threshold value in step H1 (point b in FIG. 16), or if the number of temperature rise rate changes is equal to or larger than the set value in step H2, the charging stop temperature The rate of increase is changed to a change value (C2 in FIG. 13) larger than the initial value C1, and the number of changes is set to 1 (steps H4 and H5).

Here, if the IV characteristic becomes larger than a predetermined threshold value (non-degraded state) in the following flow due to the change of the charging stop temperature rise rate to a large value,
The process proceeds from step H1 to H2, where the number of temperature rise rate changes is 1, which is smaller than the set value 2, so that step H3
The charge stop temperature rise rate returns to the initial value C1.

As described above, when the IV characteristic returns to the non-degraded state due to the change of the charging stop temperature rise rate to the large value, the charge stop temperature rise rate is returned to the original value. The problem of overcharging the battery can be avoided.

On the other hand, after the charge stop temperature rise rate is returned to the initial value, if the IV characteristic again becomes smaller than the threshold value in the subsequent flow, the charge stop temperature rise rate is again changed to the changed value C2. And the number of temperature rise value changes becomes 2 (steps H1, H4, H5). Even if the IV characteristic becomes larger than the threshold value again in the subsequent flow, the number of changes in the temperature increase rate is 2 and the set value is 2 or more in step H2. Fixed to a value.

As described above, the rate of increase in the temperature at which charging is stopped is calculated using the original value C.
If the IV characteristic falls below the threshold value again after returning to 1, the charge stop temperature rise rate is changed again to C2 and fixed, so that hunting when the IV characteristic is near the threshold value is prevented. It is possible to stabilize charging conditions and prevent fluctuation due to erroneous detection.

In step C14, the current refresh discharge is the second stage, and when this second stage discharge is completed (step C17), the cycle counter is cleared (step C18), and the step C7 is completed.
The process returns to. If the second-stage discharge is not completed in step C17, it is determined whether or not the charge stop temperature rise rate (dT / dt) has been changed (step C27). Processing returns. If the dT / dt value has been changed, the process returns to step C5.

If it is determined in step C9 that the refresh discharge is not being performed, the battery temperature, the voltage,
The current is measured (Step C19), the remaining capacity of the battery is calculated (Step C20), and the battery state data shown in FIG. 5 is transmitted to the charging device 112 (Step C2).
1).

When the charging device 112 is connected to the battery management device 105 (step C22), and a charge completion signal is detected from the "charger state data" (step C23), the process proceeds to step C1. Processing shifts to the standby mode. In steps C13 and C22, when the connection between the battery management device 105 and the charging device 112 is not detected, the above-described steps C13 and C22 are not performed.
The processing shifts to the first standby mode.

If the "charger state data" signal is not normally received in step C8, it is determined that the communication is abnormal (step C24), and the display 133 is blinked alternately as the abnormal display 2 (step C24). C
25).

Next, the operation of the charging device 112 in the charging preparation stage after the AC plug is connected will be described with reference to FIG. When the plug 123 of the charging device 112 is connected to an outlet (step D1), the battery case 100
Is detected (step D2).

When the connection is detected (step D2) and the voltage V of the rechargeable battery 102 is detected to be less than 20 V (step D3), preliminary charging with a charging current of 0.5 A is started (step D4). ), The display device 13
3 indicates that charging is in progress (step D5), the timer is turned on, and the charging time is measured (step D5).
6).

When the voltage V of the rechargeable battery 102 becomes equal to or higher than 20 V (step D7), the charging output is stopped (step D8), and the charging device 112 sends the signal to the battery management device 105 at step C2. The received charger connection signal is transmitted (step D9), and
The transmission of the "charge / discharge control data request" signal shown in FIG. 5 received in step C3 is started (step D1).
0) If the charge / discharge control data transmitted in step C6 is normally received (step D11), the mode shifts to a refresh discharge mode described later.

If the charge / discharge control data is not normally received in step D11, it is determined that the communication is abnormal (step D12), and the abnormality display 2 is displayed on the display device 13.
3 (step D13), and this process ends.

If the state in which the voltage is not higher than 20 V is continued for 60 minutes in step D7 (step D14), an abnormal display 1 is displayed on the display device 133 (step D15), and this processing ends.

Next, based on FIG.
Will be described. The charging device 112 is in the refresh discharge mode (step E
1) If the charge / discharge control data created in the step C5 includes a “refresh discharge execution request” signal (step E2), for example, the LED of the display device 133 is turned on to refresh. Is displayed, and the charging device 112
Then, transmission of the charger state data including the "charge / discharge control data request" signal to the battery management device 105 is started (step E9), and the first-stage refresh discharge of the rechargeable battery is started (step E10).

If the battery state data shown in FIG. 4 transmitted in step C12 is normally received (step E11), and it is determined that the first-stage refresh discharge is to be terminated based on the data contents (step E11). Step E1
2) The second-stage refresh discharge is started (step E13). The first-stage refresh discharge is switched from the first-stage discharge to the second-stage discharge when the battery voltage reaches the first-stage discharge stop voltage V1.

Here, the discharge capacity from the start of the first-stage refresh discharge to the switching to the second-stage refresh discharge is employed as the discharge capacity at the time of refreshing to obtain the refresh start-up capability. The discharge capacity up to the end of the second-stage discharge can be used as the discharge capacity at the time of refresh for obtaining the refreshing start capability. If it is not determined in step E12 to end the first-stage refresh discharge, and if the refresh release switch is not turned on (step E12 '), the processing of steps E11 and E12 is repeated.

Next, the battery state data shown in FIG. 4 transmitted in step C12 is normally received (step E14), and it is determined based on the data contents that the second-stage refresh discharge is to be terminated. BA (Step E1
5) The refresh display is turned off (step E1)
6) The transmission of the “charger status data” signal started in step E9 is stopped (step E1).
7) The refresh discharge is completed (step E1)
8), the mode shifts to a charging mode described later. Step E
If it is not determined at 15 that the second stage refresh discharge is to be terminated, and if the refresh release switch is not turned on (step E15 '), steps E14 and E15 are performed.
Is repeated

If the battery status data is not received normally in steps E11 and E14, a communication error is detected (steps E19 and E21) and the error display 2 is displayed.
Is displayed on the display device 133 (steps E20 and E2).
2), this process ends.

In the two-stage refresh discharge in steps E10 and E13, the first-stage discharge is performed with a pulse waveform having a current value I ₁ higher than the second-stage current value I ₀ , and the second stage is constant. This is done with current or constant resistance. And
The power consumption in the discharge of the first stage and the second stage is performed so as to be substantially equal, and the switching between the first stage and the second stage is such that the battery voltage reaches the first stage refresh discharge stop voltage. Sometimes done.

Next, based on FIG.
Will be described. When the charging device 112 shifts to the charging mode (step F1), the charging device 11
From 2, transmission of the charger status data including the “battery status data request” signal shown in FIG. 5 to the battery management device 105 is started (step F <b> 2). When the battery status data shown in FIG. 4 transmitted from the battery management device 105 is normally received in step C21 (step F3), the battery temperature in the battery status data is set in the charge / discharge control data. It is determined whether or not the charging start temperature is between the charging start lower limit temperature and the charging start upper limit temperature (step F4). If the charging start temperature is not within the charging start temperature, charging is waited (step F4).
5) The LED of the display device 133 blinks as a charge standby display (step F6), and the process proceeds to step F3.

If it is determined in step F4 that the battery temperature is within the charging start temperature, charging is started (step F7), and measurement of elapsed time by a total timer is started (step F8). "Battery state data request" shown in FIG.
Charger state data including the signal is transmitted (step F)
9). In step C21, the battery management device 105
If the battery state data shown in FIG. 4 transmitted from the controller is normally received (step F10), the end of charging is determined (step F11). If the end of charging is not determined, the process returns to step F9. Steps F9 to F1
1 is repeated.

Here, in the charge termination determination, when the battery temperature rise rate reaches the charge stop condition dT / dt (No. 11 in FIG. 3) corresponding to the dischargeable voltage transmitted from the battery management device 105, the battery voltage is increased from the maximum voltage. When the battery voltage reaches -ΔV, and when the battery temperature reaches the charging stop temperature Tco, it is determined that the charging is completed.

When it is determined in step F11 that charging has been completed based on the received battery state data, the charging device 112 sends the battery management device 105 to the battery management device 105 in step C23 of No. 9 shown in FIG. Charger state data including either the “charging completion” signal or the “charge stop” signal of No. 10 is transmitted (step F12), and the measurement of the elapsed time by the auxiliary charging timer is started (step F13), and the auxiliary charging is performed. (For example, 0.5A × 2
h) is started (step F14), and after a lapse of a predetermined time, the auxiliary charging is stopped, and this processing ends.

In step F3 or F10, if the battery state data shown in FIG. 4 from the battery management device 105 is not normally received, it is determined that a communication error has occurred (steps F16 and F18), and the error display 2 is displayed on the display device 133. (Steps F17 and F19), and this process ends.

Next, based on FIG.
Will be described. When the battery management device 105 is connected to the vehicle in the standby mode, vehicle control data is transmitted from the battery management device 105 to the vehicle traveling control unit 109 (steps G1 to G3).
The battery temperature, voltage, and current are measured, and the remaining battery capacity is calculated (G4 to G5). When it is detected that the battery voltage has dropped to the discharge stop voltage during running (step G6),
A discharge stop signal is output to the vehicle running control unit 109 (Step G7). The running discharge capacity from when the vehicle is connected to when the discharge stop voltage is detected is temporarily adopted as the running start-up battery capacity (Step G8). .

In step G8, the temporary running start actual capacity is, as shown in FIG. 11A, the cycle counter indicating the number of charge / discharge cycles of the rechargeable battery 102 is 20 or less, and the rechargeable battery 102 is charged. If the previous charge of the battery 102 has been completed normally, the self-discharge amount is equal to or less than a predetermined set value, and if the battery temperature at the time of the discharge stop is within a predetermined range, it is determined as the running start-off capability. (Steps A1 to A5). The above counter is 20
Is not below, or the last charge was not completed successfully,
If the self-discharge amount is larger than a predetermined set value, or if the battery temperature at the end of discharge is not within a predetermined range, the determination of the running start-off ability capacity is postponed and this processing is performed. finish. The self-discharge amount in step A3 is the amount of electricity that naturally discharges with the passage of time.

Further, following the determination of the actual running start capacity, the setting operation of the charge stop temperature rise rate dT / dt is performed based on the flow shown in FIG. 12 as described above (step G9).

As described above, the power supply system 21 of the present embodiment
Then, it is considered that the battery is deteriorated when the ratio of the ability capacity (refresh start ability capacity or running start ability capacity) to the initial capacity is smaller than a predetermined threshold value or when the IV characteristic is smaller than the predetermined threshold value. , The charging stop temperature rise rate (dT / dt) when the battery is deteriorated
Value) is changed to a value larger than the charging stop temperature rise rate in the case where the battery has not deteriorated. Therefore, even if the battery is deteriorated, a required charge capacity can be secured, and as a result, the battery life can be extended.

Further, it is not necessary to set the charge stop temperature rise rate in consideration of the deterioration of the battery when it is new, so that the optimum charge stop condition according to the battery state can be set, and the battery life can be extended from this point as well.

In the above embodiment, the ability capacity (refreshing start ability capacity, running starting ability capacity),
Alternatively, the charge stop temperature rise rate is changed based on the IV characteristics, but the charge stop condition can be changed by other methods. For example, the degree of battery deterioration is obtained from the battery history (the number of times of charging, the number of times of discharging, the number of times of charging / discharging cycles, etc.). It can be changed to increase the depth. Specifically, as the number of times of charging and discharging or the number of cycles of charging and discharging increases, the rate of increase in the temperature at which the charge is stopped is increased.

[Brief description of the drawings]

FIG. 1 is a side view of an electric assist bicycle according to an embodiment of the present invention.

FIG. 2 is a block diagram of a power supply system according to the embodiment.

FIG. 3 is a diagram for explaining signal data transmitted and received between a battery management device and a charging device of the power supply system.

FIG. 4 is a diagram for explaining signal data transmitted and received between a battery management device and a charging device of the power supply system.

FIG. 5 is a diagram for explaining signal data transmitted and received between a battery management device and a charging device of the power supply system.

FIG. 6 is a flowchart illustrating the operation of the battery management device.

FIG. 7 is a flowchart for explaining the operation of the charging device.

FIG. 8 is a flowchart for explaining the operation of the charging device.

FIG. 9 is a flowchart for explaining the operation of the charging device.

FIG. 10 is a flowchart for explaining the operation of the battery management device.

FIG. 11 is a flowchart for explaining the operation of the battery management device.

FIG. 12 is a map diagram for setting the charging stop temperature rise rate.

FIG. 13 is a flowchart for setting the charging stop temperature rise rate.

FIG. 14 is a battery temperature rise characteristic diagram during charging for explaining the operation and effect of changing the charge stop temperature rise rate.

FIG. 15 is a flowchart for setting the charging stop temperature rise rate.

FIG. 16 shows an I for setting the charging stop temperature rise rate.
It is a -V characteristic view.

[Explanation of symbols]

 21 power supply system 102 rechargeable battery 112 charging device (charging means) 117 battery management / control unit (charging control means)

Continued on the front page F term (reference) 2G016 CA03 CB13 CB21 CB31 CC04 CC06 CC27 CC28 5G003 AA01 BA01 CA01 CA11 CB01 EA05 EA09 FA06 GC05 5H030 AA03 AA04 AA08 AS08 BB01 BB21 DD20 FF42 FF43 FF44 FF51

Claims (8)

[Claims] 1. A power supply system for an electric vehicle, comprising: a rechargeable battery; charging means for charging the battery; and a battery management device for managing a battery state including a remaining capacity of the battery.
The power management system for an electric vehicle, wherein the battery management device changes a charging stop condition based on a battery state. 2. The power supply system for an electric vehicle according to claim 1, wherein the battery management device changes a charging stop condition according to a change in the actual capacity of the battery. 3. The power supply system for an electric vehicle according to claim 2, wherein the battery management device changes the charging stop condition so that the charging depth increases as the ratio of the actual capacity to the initial capacity decreases. 4. The battery management device according to claim 2, wherein the battery management device is configured to discharge the battery during traveling until the battery voltage reaches a preset capability capacity determination voltage value by running the vehicle, or the battery voltage during refresh discharge. The discharge capacity at the time of refresh discharged until the voltage reaches the set voltage value, or the sum of the discharge capacity at the time of travel and the discharge capacity at the time of refresh is defined as the actual capacity, and the charge stop condition is changed based on the actual capacity. Characteristic power supply system for electric vehicles. 5. The battery management device according to claim 1, wherein the condition for stopping the charging when the degree of battery deterioration obtained by the current I-voltage V characteristic curve of the battery is large is the condition for stopping charging when the degree of battery deterioration is small. A power supply system for an electric vehicle, wherein the charge depth is changed to be deeper than a condition. 6. The charge stop condition according to claim 2, wherein the charge stop condition is restored when the actual capacity or the battery deterioration degree after changing the charge stop condition is restored to a predetermined threshold value or more. Power supply system for electric vehicles. 7. The charge stop condition according to claim 6, wherein the charge stop condition is changed again when the actual capacity or the battery deterioration degree falls below a predetermined threshold value after the charge stop condition is restored. A power supply system for an electric vehicle, which is fixed to a condition. 8. The battery management device according to claim 1, wherein the battery stop degree is determined based on the battery history (the number of times of charge, the number of times of discharge, the number of times of charge / discharge cycles, etc.). A power supply system for an electric vehicle, wherein a charge depth is changed to be deeper than a charge stop condition when the charge becomes small.