JP4242998B2 - Battery temperature equalization control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a battery temperature equalization control device in an assembled battery used for an electric vehicle or the like.
[0002]
[Prior art]
In recent years, attention has been paid to global environmental countermeasure technology against the backdrop of global environmental problems such as ozone holes and global warming, and in the automobile industry, the development of electric vehicles that suppress carbon dioxide emissions has become active. As the energy source, a large-capacity assembled battery having a large energy has been used by connecting a large number of batteries typified by lithium ion batteries and nickel metal hydride batteries.
[0003]
On the other hand, in batteries typified by lithium ion batteries and nickel metal hydride batteries, there are upper and lower limits on the usable temperature. However, even if the battery temperature is within the usable range, the performance of the battery as described above is greatly different between a low temperature and a high temperature. For example, in a nickel metal hydride secondary battery, various battery characteristics such as battery voltage, discharge capacity, charge efficiency, and discharge efficiency vary depending on temperature. For this reason, in a battery pack in which a plurality of battery cells are connected, if a temperature difference occurs between the battery cells, there may be a difference in the discharge capacity or charge / discharge depth between the battery cells, or the life of the battery pack may be shortened. was there. In particular, a large-capacity assembled battery used for an electric vehicle or the like has a large volume of the assembled battery, and may be accompanied by an internal combustion engine such as a hybrid type. Therefore, a temperature difference is easily generated between the battery cells in the assembled battery, Many problems as described above occurred.
[0004]
In order to solve such a problem, Japanese Patent Application Laid-Open No. 11-213962 eliminates a temperature difference between batteries by attaching a single metal plate between battery cells.
[0005]
[Problems to be solved by the invention]
However, in this method, since it was not confirmed whether the temperature difference could be reduced, sometimes the assembled battery continued to be used while the temperature difference between the battery cells was not eliminated. .
[0006]
[Means for solving the problems]
The present invention includes an assembled battery 11, a plurality of battery temperature measuring means 121 to 12n for measuring the temperature of the assembled battery 11, a battery temperature adjusting means 13 for adjusting the temperature of the battery, a battery temperature measuring means 121 to 12n, and a battery. The assembled battery system including the control means 14 for controlling the temperature adjusting means 13 is characterized in that the battery temperature adjusting means 13 is controlled based on the battery temperature measured by the battery temperature measuring means 121 to 12n.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described.
[0008]
First, the principle of the present invention will be described. In FIG. 1, the assembled battery 11, a plurality of battery temperature measuring means 121 to 12n for measuring the temperature of the assembled battery 11, a battery temperature adjusting means 13 for adjusting the temperature of the battery, the battery temperature measuring means 121 to 12n, and the battery The assembled battery system provided with the control means 14 for controlling the temperature adjusting means 13 is characterized in that the battery temperature adjusting means 13 is controlled based on the battery temperature measured by the battery temperature measuring means 121 to 12n.
[0009]
Next, the example which implemented this invention to the assembled battery for electric vehicles is demonstrated.
[0010]
The battery used in the examples is an assembled battery for an electric vehicle in which 40 lithium ion secondary battery cells having an average discharge voltage of 3.6 V are connected in series. FIG. 2 is a configuration diagram of an assembled battery for an electric vehicle to which the battery temperature equalization control system according to the present invention is applied. In FIG. 2, reference numerals 200 to 209 denote battery blocks obtained by dividing 40 lithium ion secondary battery cells into 10 pieces each having four pieces, and 210 to 219 denote battery temperature measuring means for measuring the temperature of the battery blocks, which are composed of, for example, a thermistor. Has been. Reference numerals 220 to 229 denote partition walls for partitioning adjacent battery blocks, and 23 denotes a battery temperature adjusting means, which is constituted by, for example, a cooling fan indicated by 240 to 249 and a blower pipe indicated by 25. The cool air taken from outside air is guided to each battery block. Reference numeral 27 denotes control means for controlling the battery temperature measuring means 220 to 229 and controlling the cooling fans 240 to 249.
[0011]
In the battery temperature equalization control apparatus according to the present invention, the control unit 27 controls the cooling fans 240 to 249 so as to reduce the difference between the battery temperatures based on the battery temperatures measured by the battery temperature measurement units 210 to 219. It is characterized by doing. The control method according to the present invention is realized by software on a microcomputer, for example.
[0012]
Next, an example of the control method in the present invention will be described.
[0013]
In FIG. 3, in step 31, the voltages of the thermistors 210 to 219 are AD converted to obtain the temperature of each battery block.
[0014]
In step 32, | the temperature of each battery block−the minimum value of temperature | is compared with a preset threshold value,
| Temperature of each battery block−minimum value of temperature | ≧ The cooling fan of the battery block satisfying the threshold value is turned on, and the cooling fans corresponding to the other battery blocks are turned off. Here, the threshold is set to 5 ° C., for example.
[0015]
If the steps 31 and 32 are executed periodically, for example, by timer interruption every 10 seconds, the temperature difference between the batteries can be reduced.
[0016]
FIG. 4 shows the transition of the temperature of each battery block and the cooling fan when the control method described in FIG. 3 is applied. FIG. 4 shows the relationship between the elapsed time and the temperature of the battery block, and the operating state of the cooling fan is shown in parentheses. According to this, there was a maximum temperature difference of 12 ° C. between the battery block 1 and the battery block 10 in 41 steps, but after 700 msec indicated in 48 steps, the temperature difference was reduced to 4 ° C. Can be confirmed.
[0017]
In addition, when applied to a system having an internal combustion engine that is a large heat source, such as a hybrid vehicle, by adding a blow pipe switching valve 550 to 559 that can switch between cold air and hot air as shown in FIG.
If the temperature of each battery block-average value of temperature ≥ threshold value, set the cool air and turn the fan,
Average value of temperature-When the temperature of each battery block ≤ threshold, if the control is performed by turning the fan with warm air, the battery temperature is equalized around the average value, and only the cooling fan shown in Fig. 2 Can equalize faster.
[0018]
【The invention's effect】
Thus, the battery temperature in the assembled battery can be equalized accurately by using the method of the present invention that equalizes the temperature difference between the batteries based on the actual battery temperature.
[Brief description of the drawings]
FIG. 1 is a diagram showing the principle of a battery temperature equalization control device according to the present invention.
FIG. 2 is a configuration diagram of a battery temperature equalization control device according to an embodiment of the present invention.
FIG. 3 is a flowchart in the embodiment of the present invention.
FIG. 4 shows changes in battery temperature and cooling fan state in the embodiment of the present invention.
FIG. 5 is a configuration diagram of a battery temperature equalization control device according to an embodiment of the present invention.
[Explanation of symbols]
11: assembled batteries 121-12n: battery temperature measuring means 13: battery temperature adjusting means 14: control means 200-209: battery blocks 210-219: battery temperature measuring means 220-229: partition wall 23: battery temperature adjusting means 240-249 : Battery cooling fan 25: Blower pipe 26: Cooling air 27: Control means 500 to 509: Battery blocks 510 to 519: Battery temperature measuring means 520 to 529: Partition wall 53: Battery temperature adjusting means 540 to 549: Fan 550 to 559: Air blowing Pipe switching valve 560: Cold air pipe 561: Hot air pipe 57: Cold air 58: Hot air 59: Control means

Claims (2)

An apparatus for equalizing a temperature difference between batteries in an assembled battery to which a plurality of battery cells are connected,
The assembled battery;
A plurality of battery temperature measuring means for measuring the temperature of the battery;
Battery temperature adjusting means for adjusting the temperature of the battery;
In an assembled battery system comprising control means for controlling the battery temperature measuring means and the battery temperature adjusting means,
The assembled battery has a plurality of battery blocks,
The battery block is formed by dividing the plurality of battery cells,
The battery temperature measuring means measures the temperature of the battery block,
| Battery temperature equalization control apparatus for controlling the battery temperature adjusting means to equalize the battery temperature so as to cool the battery block that satisfies the temperature-minimum value of each battery block | ≧ threshold . An apparatus for equalizing a temperature difference between batteries in an assembled battery to which a plurality of battery cells are connected,
The assembled battery;
A plurality of battery temperature measuring means for measuring the temperature of the battery;
Battery temperature adjusting means for adjusting the temperature of the battery;
In an assembled battery system comprising control means for controlling the battery temperature measuring means and the battery temperature adjusting means,
The assembled battery has a plurality of battery blocks,
The battery block is formed by dividing the plurality of battery cells,
The battery temperature measuring means measures the temperature of the battery block,
The battery is configured such that cold air is blown to battery blocks satisfying the temperature-average temperature value of the battery block ≧ the threshold value, and hot air is blown to battery blocks satisfying the average temperature value−temperature of each battery block ≦ the threshold value. A battery temperature equalization control device that controls temperature adjustment means to equalize battery temperature.

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