JPH04143568A - Cold accumulating type cooling device - Google Patents

Abstract

PURPOSE:To permit the determination of the life of batteries properly in accordance with the variation of the charging characteristics of respective batteries by a method therein the title device is provided with an amount of voltage drop detecting unit, detecting the reduced amount of terminal voltage of the battery after discharging for a predetermined period of time, and a battery life deciding unit, deciding the timing of replacement of the battery when the detected reduced amount of voltage has exceeded a predetermined threshold value. CONSTITUTION:A decision whether a difference between read terminal voltage V and an initial battery voltage VO or the amount of voltage drop V is higher than a predetermined threshold value Vb or not is repeated until the counting of a timer B is finished. However, when the amount of voltage drop V becomes higher than the threshold value Vb during this period, the life of the battery is decide to have expired and a lamp 54 is lighted. On the other hand, when the amount of voltage drop V has not become higher than the threshold valve Vb during a period until the counting of the timer B is finished, it is decided that the time of replacement of the battery has not arrived and the lamp 54 is not lighted. According to this method, the replacement of the battery can be effected correctly in spite of the variations of the initial voltage VO of the battery.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a regenerator type cooling device, and particularly to a battery life determination device thereof.

[Conventional technology] A cold storage container is known as a cold storage type cooling device.

This cold storage container is equipped with a cold storage agent, an electric fan that sends the cold heat of the cold storage agent to the cooled part, and a battery that drives the electric fan. After storing the cold and charging, the electric fan supplies the cold heat as appropriate.
The cooled part, that is, the inside of the refrigerator, is always kept within a constant temperature range.

In this type of device, when the battery reaches the end of its lifespan, the cold food etc. become defective due to a lack of cold heat supply.
In addition, there may be cases where battery fluid leaks.

Japanese Patent Application Laid-open No. 2'-40473 discloses that the operating time of an electric fan is accumulated, and the accumulated operating time reaches a predetermined threshold time.
And when the battery terminal voltage falls below a predetermined value,
It notifies you that it is time to replace the battery.

[Problems to be Solved by the Invention] However, there are variations in the terminal voltage of each battery when fully charged (see Fig. 8), and therefore,
The battery terminal voltage at the time of battery replacement also varies. That is, a battery with a high terminal voltage when fully charged will not be able to maintain the required discharge current value at a higher terminal voltage value than a battery with a lower terminal voltage when fully charged, and the battery will need to be replaced.

Therefore, as in the conventional battery replacement timing notification (battery life detection) method described above, when the battery terminal voltage falls below a predetermined threshold after a certain cumulative discharge time, it is determined that it is time to replace the battery (battery life). Then, a battery whose terminal voltage is high when fully charged has a problem that the preferred replacement period is exceeded (necessary discharge current cannot be obtained). Conversely, if a battery has a low terminal voltage when fully charged, it may be determined that it is time to replace it even though it has discharge capacity.

The present invention was made in view of such problems, and an object of the present invention is to provide a regenerator cooling device that can determine an appropriate battery life depending on variations in discharge characteristics of individual batteries.

[Means for Solving the Problems] The cold storage type cooling device of the present invention includes a cold storage agent, an electric fan that sends cold heat of the cold storage agent to a cooled part, a battery that drives the electric fan, and a lifespan of the battery. In the regenerator cooling device, the battery life determining means includes a voltage drop amount detection section that detects the amount of drop in battery terminal voltage after discharging for a predetermined time; The present invention is characterized by comprising a battery life determination section that determines that it is time to replace the battery when a predetermined threshold value is exceeded.

[Operation and Effects of the Invention] As explained above, in the regenerator cooling device of the present invention, since the electric fan has a constant load, if the amount of battery voltage drop exceeds a predetermined threshold after a predetermined discharge time has elapsed, It has been determined that it is time to replace the battery.

In this way, for a battery whose terminal voltage is originally high when fully charged, it is determined that it is time to replace the battery based on the high terminal voltage, so it is possible to prevent the battery from being used beyond the time for battery replacement. On the other hand, since a battery whose terminal voltage is originally low when fully charged is determined based on the low terminal voltage, it will not be determined that it is time to replace the battery even though it has discharge capacity.

As a result, it is possible to determine an appropriate battery life depending on variations in discharge characteristics of individual batteries.

[Example] An embodiment of the regenerator type cooling device of the present invention is shown in FIG.

This cold storage type cooling device is a cold storage container with casters, and includes a cold storage agent 1, an electric fan 3 that sends cold energy from the cold storage agent to a refrigerator compartment (cooled part) 2, and a battery 4 that drives the electric fan 3. and a control section 5 are built into the upper part.

As shown in FIG. 2, the control unit 5 includes a charge switching relay 51
, a charger 52, a thermostat 53, a microcomputer 50, and a battery replacement command lamp 54. here,
As shown in FIG. 1, the microcomputer 50 constitutes the battery life determination means (voltage drop detection section, battery life determination section) in the present invention.

The charger 52 includes a transformer that converts input AC voltage into a predetermined low voltage, a full-wave rectifier that performs full-wave rectification of the voltage-converted AC voltage, a smoothing circuit that smoothes the rectified voltage, and a smoothed DC voltage value. The battery charger has a built-in SCR current control circuit that controls the battery charger and charges the battery to a predetermined voltage with a constant current, but since such a battery charger is well known, further detailed explanation will be omitted.

When the input terminal pair 55 of the control unit 5 is connected to the commercial AC power supply 100, a current flows through the charge switching relay 51 and ACl 00V is applied to the charger 52. At this time, the switching contact 51a of the charging switching relay 51 falls to the charger 52 side,
Charger 52 charges battery 4 . After sufficient charging, when the input terminal pair 55 of the control unit 5 is connected to the commercial AC power supply 100, the switching contact 51a of the charging switching relay 51 falls to the electric fan 3 side, and the battery 4 is connected to the electric fan 3 via the thermostat 53. to drive the electric fan 3. Note that the thermostat 53 is installed in the refrigerator compartment 2, and is set to be conductive at, for example, 6°C and shut off at 3°C.

Further, the terminal voltage of the battery 4 is input to the microcomputer 50, and the microcomputer 50 drives the battery replacement command lamp 54.

Next, the operation of the microcomputer 50 will be explained with reference to the flowchart shown in FIG.

First, timer A built in the microcontroller is activated by inputting the battery voltage.
, starts B (SIO). Here, timer A is a timer for determining the time point at which terminal voltage drop rate measurement starts, that is, a timer for measuring the battery voltage value at the time point when battery 4 starts discharging, and the set time Ta is 15 minutes. The reason why the battery voltage after a time Ta after the start of discharging is used as the reference value for comparison is because the forced charging of the charger 52 does not cause much variation in the terminal voltage in the early stage of discharging. After approximately several minutes or more have elapsed from the start of discharge, the terminal voltage varies depending on the discharge characteristics of each battery and becomes stable. Timer B is a timer for setting the time (Tb-Ta) for measuring the terminal voltage drop rate, and the set time Tb of timer B is 3 hours.

Next, the process waits until timer A ends (S12), and when timer A ends, the battery terminal voltage at this point in time (referred to as initial battery voltage Vo) is read (314).

Next, reading the battery terminal voltage V (S16), and
The determination (318) of whether the difference between the read terminal voltage V and the initial battery voltage ■0 (voltage drop amount Δ■) is greater than or equal to a predetermined threshold value Δvb is repeated until timer B ends (S
20). However, during that time, the voltage drop amount ΔV becomes the threshold value Δ
If it is equal to or higher than vb (318), the lamp 54 is turned on, indicating that the battery has reached the end of its life (S24>).

In addition, during the period until timer B ends, the voltage drop amount ΔV
If it does not exceed the threshold value Δvb (S20>, it is assumed that the battery has not reached the time for replacement, and the lamp 54 does not light up.

In this way, despite variations in the initial battery voltage Vo, the terminal voltage drop rate of the battery at the end of its life is generally within a certain range, so that the battery can be replaced accurately.

Figure 4 shows the discharge voltage drop characteristics of the battery.

The battery in the early stage of service has a time Tb as shown in the characteristic line A1.
There is almost no voltage drop within the range of -Ta. In contrast, a battery that has reached the end of its life causes a large discharge voltage drop, as shown by the shaded area 3r in FIG.

In the above embodiment, the timer B is the thermostat 53.
Although it is configured to count regardless of whether the electric fan 3 is on or off, the time during which the electric fan 3 is actually operated may be counted instead.

The reason why the timer B counts regardless of whether the thermostat 53 is turned on or off will be explained below.

This point is an important feature of the regenerator type cooling device of this embodiment.

Figure 5 shows the change in outside air temperature and the above voltage drop ΔV=V=VO
Indicates the relationship between When the outside temperature rises, the reaction inside the battery 4 becomes more active, and even in a battery that has reached the end of its life, the voltage drop amount ΔV decreases.

However, the heat load on the refrigerated container increases as the outside air temperature rises, and as a result, the operating rate of the electric fan 3 increases almost in proportion to the rise in outside air temperature, as shown in FIG.

Therefore, when the outside temperature rises, the
The actual discharge time within Ta) is a certain time (Ta)
a>, the voltage drop amount V increases accordingly. Conversely, when the outside temperature decreases, the actual discharge time within a certain period of time (Tb-Ta) decreases
(N is a positive number less than or equal to 1) times the voltage drop Δ
V decreases.

In the end, the life has come to an end because the change in the voltage drop △V, which is linked to outside temperature fluctuations, and the change in the voltage drop Δ■, which is almost proportional to the operating rate of the electric fan 3, which is linked to outside temperature fluctuations, cancel each other out. Voltage drop amount ΔV of the battery in a predetermined time range
As shown in FIG. 7, is almost constant regardless of fluctuations in outside temperature.

Therefore, according to the regenerator type cooling device of this embodiment, the outside temperature can be detected and the battery voltage drop amount AV due to the outside temperature can be detected.
Even without performing correction, it is possible to determine the battery life more accurately.

Furthermore, in this embodiment, even if the charge at the start of discharge is not fully charged, the initial discharge voltage VO decreases, so the amount of voltage drop becomes small, and unlike the above-mentioned prior art, the absolute discharge voltage value does not change. Misjudgments are less likely to occur when compared.

In addition, in this embodiment, a predetermined period of time (15 minutes) is used at the initial stage of discharge.
Do not measure the voltage drop rate. Therefore, more accurate lifespan determination is possible.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view of a refrigerated container as an embodiment of the present invention, Fig. 2 is a block diagram of the control section, Fig. 3 is a flowchart of the microcomputer, Fig. 4 is a discharge characteristic diagram of the battery, and Fig. 5 is a diagram of the discharge characteristics of the battery. The figure is a characteristic line showing the relationship between outside air temperature and the amount of voltage drop at constant current of the battery, Figure 6 is a characteristic line showing the relationship between outside air temperature and electric fan voltage operation rate, and Figure 7 is outside air temperature. FIG. 8 is a characteristic diagram showing the relationship between temperature and voltage drop of the device of this embodiment, and FIG. 8 is a diagram showing variations in discharge voltage characteristics of the battery. FIG. 9 is a complaint correspondence diagram. 1...Cold storage agent 3...Electric fan 4...Battery 5...Control unit (battery life determination means) (Voltage drop amount detection unit) (Battery life determination unit)

Claims (1)

[Claims] A cold storage type comprising a cold storage agent, an electric fan that sends the cold heat of the cold storage agent to a cooled part, a battery that drives the electric fan, and a battery life determination means that detects the life of the battery. In the cooling device, the battery life determining means includes a voltage drop amount detection section that detects the amount of drop in battery terminal voltage after discharging for a predetermined time, and a voltage drop amount detection section that detects the amount of drop in battery terminal voltage after discharging for a predetermined time, and determines when it is time to replace the battery when the detected amount of voltage drop exceeds a predetermined threshold. A regenerator cooling device comprising: a battery life determination unit that determines the battery life.