JP5097189B2 - Capacity degradation storage battery cell group detection method and storage battery group capacity degradation suppression control device - Google Patents

Description

  The present invention relates to a driving battery mounted on an electric vehicle.

In recent years, electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in vehicles (PHEVs), and fuel cell vehicles (HEVs) have been developed for environmental measures and fuel efficiency improvements. FCEV (Fuel Cell Electric Vehicle) has attracted attention.
Among these, one of the important technical points is a driving battery mounted on a vehicle and a control method including charging thereof. The automobile requires a storage battery as a secondary battery that can be charged and discharged with a high voltage of several hundred volts and a large capacity, and is composed of an assembled battery that combines a plurality of storage battery cells. Since a large number of storage battery cells are mounted, characteristic variations occur between the storage battery cells. The characteristics of the assembled battery when a plurality of storage battery cells are connected in series are combined, and the characteristics of the storage battery cell with the worst or deteriorated characteristics are dominant. It becomes a problem.
In addition, cruising distance (electric cost) is regarded as important as the merchandise of the electric vehicle. In order to extend this cruising distance, it is possible to suppress variations in the storage capacity characteristics as well as the storage capacity characteristics of the assembled storage battery and the plurality of storage battery cells constituting the storage battery in various characteristics of the storage battery. It becomes important.
This characteristic variation of the storage capacity may be a variation at the time of manufacture or a variation of deterioration caused by a change over time due to use. Further, this deterioration may proceed due to overcharge, overdischarge, or temperature control. Therefore, it is important to manage the entire assembled battery and the SOC (State of charge), which is the power storage state of a plurality of storage battery cells constituting the battery, and to prevent the deterioration of the power storage capacity caused thereby. It becomes a problem.
Moreover, suppressing the variation in the storage capacity of the plurality of storage battery cells is an important factor not only from the viewpoint of improving the cruising distance (electricity cost) but also from the viewpoint of preventing early output limitation, power performance, and improving the service life.
There is Patent Document 1 as a conventional technique for detecting the deterioration state of the secondary battery. In Patent Document 1, the battery voltage during the charging process is continuously measured and stored, and on the basis of the characteristic of the measured value, a state in which the battery is charged 100% (may be expressed as SOC 100%) is estimated. I was taking the way.

JP 2007-166789 A

In a battery system in which the storage capacity-open voltage characteristics (SOC-OCV characteristics, OCV: Open Circuit Voltage) are flat, it is difficult to calculate the intermediate SOC by voltage. Even if SOC variation occurs, the vehicle (storage battery ECU) is difficult to recognize. Therefore, in Patent Document 1, which is the prior art, it is necessary to sample the voltage from the start of charging, and a large storage capacity must be ensured.
In particular, in an assembled battery combining a plurality of storage battery cells, when trying to detect a relatively deteriorated storage battery cell, the voltage transition must be sampled for each storage battery cell, and the storage capacity is enormous. become.

  Therefore, the present invention has been made to solve the above-described problems, and an object thereof is to derive a battery cell group whose capacity has deteriorated with a simple configuration.

In order to achieve the above object, each invention is configured as follows.
That is, the capacity degradation storage battery cell group detection method of the invention according to claim 1 is the capacity degradation of the assembled battery composed of a plurality of storage battery cells having voltage characteristics in which the voltage follows the increase in the storage capacity. A method of detecting a storage battery group, wherein charging is performed until any storage battery cell of the assembled storage battery reaches an upper limit voltage determined in a voltage region in which the voltage rises following an increase in storage capacity, The storage battery cell that has reached the upper limit voltage after charging is charged so as to maintain the upper limit voltage, and after charging until the charging current value becomes a predetermined current value or less, the voltage of all the storage battery cells is detected, Storage battery cell groups that are relatively deteriorated are detected by comparing voltage average values for each area where the storage battery cells are arranged .

With this configuration, without overcharging the storage cell with the most deteriorated capacity, it is charged to a capacity within an appropriate range, the voltage of all the storage battery cells is detected, and the voltage average value for each area is compared with each other relatively. A deteriorated battery cell group is detected.

  According to a second aspect of the present invention, there is provided a method for detecting a capacity deterioration storage battery cell group, wherein the capacity deterioration storage battery cell group is subjected to capacity deterioration suppression control in which cooling capacity is distributed with priority given to the capacity deterioration storage battery cell group.

  With this configuration, the progress of deterioration of the storage battery cell group having a low capacity is prevented.

  According to a third aspect of the present invention, there is provided a capacity deterioration storage battery cell group detection method including a rectifying plate having a variable angle in the capacity deterioration suppression control for distributing cooling air with priority given to the capacity deterioration storage battery cell group.

  With such a configuration, the progress of the deterioration of the low-capacity storage battery cell group is prevented by selectively cooling.

  According to a fourth aspect of the present invention, there is provided a capacity deterioration storage battery cell group detecting method comprising a slit that can be opened and closed or moved in capacity deterioration suppression control for distributing cooling air with priority given to the capacity deterioration storage battery cell group.

  With such a configuration, the progress of the deterioration of the low-capacity storage battery cell group is prevented by selectively cooling.

  According to the capacity deterioration storage battery cell group detection method of the invention according to claim 5, the charging is plug-in charging using a household power source.

  With this configuration, the charging is set at the time of plug-in charging using a household power source.

In addition, the capacity deterioration storage battery cell group detection method of the invention according to claim 6 is not performed when the quick charger is connected.

  Such a configuration does not hinder the operation of rapid charging.

Moreover, the capacity deterioration storage battery cell group detection method of the invention according to claim 7 is not performed when the temperature is lower than a predetermined temperature .

  With this configuration, problems due to an increase in the internal resistance of the battery at low temperatures are prevented.

In addition, the capacity deterioration storage battery cell group detection method according to the eighth aspect of the invention is not performed during a predetermined time period.

  With this configuration, troubles are prevented by timekeeping with a clock, not with a thermometer.

Further, the storage battery cell group capacity deterioration suppression control device of the invention according to claim 9 is an electric vehicle that performs plug-in charging using a household power source, and a charging device that charges electricity to an assembled battery composed of storage battery cells. A voltage detection device that detects a voltage of the storage battery cell group in the assembled battery, and a capacity deterioration suppression device that distributes cooling air; and the storage battery increases the storage capacity by the charging device and the voltage detection device. The battery is charged until any storage battery cell of the assembled battery reaches an upper limit voltage determined within a voltage region in which the voltage follows and rises, and the storage battery cell that has reached the upper limit voltage after the charging was charged to maintain the voltage, detects the voltage of all the battery cells after the charging current value was charged until equal to or less than a predetermined current value, the battery cell is disposed Detecting a battery cell group is relatively deteriorated by comparing the average voltage of each area together by said voltage detecting device and the capacity deterioration prevention device, to the storage battery cell group in said set battery, Capacity deterioration suppression control is performed to distribute cooling air with priority given to the capacity deterioration storage battery cell group.

With such a configuration, without overcharging the storage battery cells whose capacity has deteriorated, the storage battery cell group in the assembled battery is charged, the voltage of all the storage battery cells is detected, and the voltage average value for each area where the storage battery cells are arranged As a result, the storage battery cell group having a relatively deteriorated capacity is preferentially cooled, so that further deterioration of the capacity is prevented.

  According to the present invention, it is possible to derive a storage battery cell group whose capacity has deteriorated with a simple configuration.

It is a flowchart which shows the control flow of the plug-in charge of the storage battery which concerns on embodiment of this invention. It is a characteristic view which shows the relationship between the electrical storage capacity value of the storage battery cell which concerns on embodiment of this invention, and a battery voltage. It is a figure which shows the process of charge of the storage battery which concerns on embodiment of this invention. It is a figure which shows the temperature state for every area | region of the storage battery which concerns on embodiment of this invention. It is a figure which shows the temperature state for every area | region of the storage battery which concerns on embodiment of this invention. It is a figure which shows the 1st method of cooling for every area | region of the storage battery which concerns on embodiment of this invention. It is a figure which shows the 2nd method of cooling for every area | region of the storage battery which concerns on embodiment of this invention. It is a block diagram for every function of the electric system containing the storage battery which concerns on embodiment of this invention. It is a layout view in the electric vehicle of the main electric equipment when plug-in charging the storage battery according to the embodiment of the present invention. It is a circuit diagram which shows the general | schematic relationship of the charging device and storage battery cell when charging the storage battery cell which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a flowchart showing a control method when plug-in charging a storage battery according to an embodiment of the present invention. Note that plug-in charging using a household power source is charging performed using a power source with a low capacity of 100 V or 200 V, which is a general household power source.
In this flow chart, (1) charging characteristics and variation of storage battery (2) charging method for a plurality of storage battery cells with variation (3) temperature variation and characteristic variation of assembled battery (4) cooling wind and storage cell temperature (5 ) Cooling air control method (2 methods)
Since these are important points, these will be described first, and then the description will return to the flowchart again.

((1) Storage battery storage characteristics and variations)
FIG. 2 is a diagram showing characteristics when charging a storage battery, in which the horizontal axis indicates the storage capacity value in the battery storage process, and the vertical axis indicates the battery voltage of the battery. When the storage battery cell is charged, the storage capacity of the storage battery cell increases and the open circuit voltage increases. (In addition, in charging a storage battery, the charging voltage and the open-circuit voltage of the storage battery are generally not equal. The vertical axis of FIG. 3 to be described later is the charging voltage. Also, the amount of charge stored in the battery is However, it is customary to express this amount of charge by the storage capacity (Ah) of how many amperes (A) and how many hours (h) can flow. Then, the term “storage capacity” is used.)
The characteristics of the plurality of storage battery cells vary depending on variations during manufacture, usage conditions, and temperature conditions. What is indicated by the characteristic line 201 by the continuous line of the point ◎ is a characteristic when there is almost no deterioration in a new storage battery cell. The characteristic line 202 indicated by the continuous line of the symbol ○ point is the characteristic of the storage battery cell that has deteriorated to some extent. If a new storage battery cell having the characteristic line 201 deteriorates due to a change with time, the characteristic shifts to the characteristic line 202. The storage capacity value reaching the open-circuit voltage 210 of a predetermined voltage is lower than the characteristic line 201 of the new storage battery cell, and the characteristic line 202 of the deteriorated storage battery cell is reached with a smaller storage capacity value. In FIG. 2, there are almost two scales.

As the charging of the storage battery proceeds, the open circuit voltage (OCV) increases, and the open circuit voltage rapidly rises at a certain characteristic point in a state where the storage is almost 100%. In addition, since a storage battery cell having a certain degree of deterioration has a lower storage capacity value than a new storage battery cell having a large storage capacity value that can be stored, the open-circuit voltage is high, and it starts to rise rapidly. This is because the capacity value that can be stored has deteriorated and the storage capacity becomes full with a small storage capacity value, so that the open circuit voltage increases.
At the characteristic point where the open circuit voltage suddenly starts to rise, it may be considered that the storage (or charging) is 100% (SOC 100%). As described above, when the storage battery cell is deteriorated, this steep rise occurs at a characteristic point where the storage capacity value is small.

  Further, what is indicated by the characteristic line 203 by the broken line at the point of the symbol Δ is the characteristic during charging. As the storage battery cell, the characteristic line 203 indicated by △ and the characteristic line 202 indicated by ◯ are the same, but since there is an internal resistance of the storage battery cell, the product of the current value flowing through charging and the internal resistance is the product. The characteristic line 203 indicates a higher voltage by the amount (for example, the rising pressure portion 223). Further, for the same storage battery cell, the characteristic line 202 is an open-circuit voltage characteristic, and the characteristic line 203 is a charge voltage characteristic. Therefore, it is possible to grasp the characteristic point of the steep rise while charging. In any case, the characteristic point of this steep rise is captured and it is grasped that it has approached SOC 100%.

In order to capture the characteristics of this steep rise, it is more effective to use a storage battery that has a flat open voltage in the intermediate SOC region and a sharp open voltage rise in the high SOC region. For example, when LiFePO4 is used for the positive electrode and a graphite system is used for the negative electrode, this characteristic becomes remarkable.
However, if there is a steep rise in the open circuit voltage, it can be grasped that the SOC has approached 100%. Therefore, the characteristics of the open circuit voltage in the intermediate SOC region do not necessarily have to be flat.

((2) Charging method for a plurality of storage battery cells with variations)
FIGS. 3A and 3B are diagrams showing the relationship among a charging voltage, a charging current, a storage capacity, and a charging time in a step of charging a plurality of storage battery cells having variations at the same time.
FIG. 3A shows the relationship between the charging voltage of each storage battery cell, the storage capacity, and the elapsed time, and FIG. 3B shows the relationship between the charging current of the storage battery cell and the elapsed time.
3A and 3B, the battery cells 1011 to 1016 are connected in series as shown in FIG. 10, and a voltage is applied to both ends connected in series by the charging device 1001. Do it all at once. FIG. 10 schematically shows in what circuit configuration each characteristic of FIGS. 3A and 3B is measured. The number of storage battery cells 1011 to 1016 and voltmeters 1021 to 1021 are shown. The arrangement of 1026 does not necessarily match the embodiment of the present invention. Further, the charging device 1001 in FIG. 10 corresponds to a charger 813 (FIG. 8) and a joining board 814 (FIG. 8) described later in the embodiment of the present invention.

  In Fig.3 (a), the vertical axis | shaft represents the charging voltage added to a storage battery cell. The charging voltage is the sum of the open voltage of each storage battery cell and the voltage increase caused by the product of the internal resistance of each storage battery cell and the current flowing through the storage battery cell. Therefore, the charging voltage on the vertical axis is different from the open circuit voltage of each storage battery cell. Moreover, since the characteristic and state of each storage battery cell generally vary, the charging voltage applied to each storage battery cell is slightly different for each storage battery cell. Moreover, the horizontal axis represents both the storage capacity of each storage battery cell and the time since the start of charging.

  Moreover, the vertical axis | shaft of FIG.3 (b) represents the charging current when charging is performed. Since each storage battery cell is connected and charged in series, the charging currents of each storage battery cell are all equal. Moreover, the horizontal axis represents the time since the start of charging. In FIGS. 3A and 3B, the time from the start of charging on the horizontal axis corresponds as it is.

First, charging of the assembled battery in a state where the storage capacity is reduced by discharging is started via the charger 813 (FIG. 8) and the joining board 814 (FIG. 8) (charging device 1001 (FIG. 10)). As described above, charging is performed in a lump by applying voltage to both ends connected in series with each storage battery cell in series. This is t = 0 in FIGS. 3A and 3B, which is a point 331 in FIG.
Further, the voltage applied at this time is almost equal to a predetermined charging current value I _E (FIG. 3) by the charger 813 (FIG. 8) and the joining board 814 (FIG. 8) (charging device 1001 (FIG. 10)) including a uniformizing circuit. An appropriate voltage is adjusted and applied so as to satisfy (b)). While each storage battery cell does not satisfy the respective storage capacity, it is performed while being adjusted so as to be charged with a voltage sufficiently higher than the open circuit voltage of each storage battery cell, and preferably with a substantially constant current value _IE. . As described above, the charger 813 (FIG. 8) and the joining board 814 (FIG. 8) (charging device 1001 (FIG. 10)) connect each storage battery cell in series and apply a voltage to both ends connected in series. However, in FIG. 3A, the charging voltage per unit applied to each storage battery cell is shown.

  In this charging process, each storage battery cell is charged, the storage capacity value increases, and the open circuit voltage also increases. Accordingly, the charger 813 (FIG. 8) and the junction board 814 (FIG. 8) (charging device 1001 (FIG. 10)) increase the charging voltage. It should be noted that the characteristics vary due to manufacturing variations among the storage battery cells and deterioration. FIG. 3A illustrates the characteristics 316 of the storage battery cell with the highest deterioration and the highest charging voltage, and the characteristics (line) 311 of the storage battery cell with the least deterioration and a low charging voltage. Further, this section is represented as (E) region.

Eventually, the storage voltage of the storage battery cell with the characteristic line 316 having the smallest storage capacity and the highest charging voltage (V _MAX ) is predetermined due to manufacturing variation among the storage battery cells and deterioration. Reach the charging voltage. This means that the SOC of the storage battery cell with the smallest storage capacity has approached 100%. When the SOC is further charged from 100%, the battery further stores electricity, and when a certain limit is exceeded, reactions such as decomposition of the electrolyte solution and change in the crystal structure of the active material are induced, and heat is generated in a chain, further deterioration of the battery. Invite. When the joining board 814 (FIG. 8) (charging device 1001 (FIG. 10)) detects that this V _MAX has reached a predetermined charging voltage, the charger 813 is configured not to apply a voltage higher than the predetermined charging voltage to the storage battery cell. The charging voltage is adjusted by the function of the joining board 814 (FIG. 8) (charging device 1001 (FIG. 10)) including the uniforming circuit (FIG. 8). Here, the process proceeds to “constant voltage charging”. This transition point is the point 332 in FIG.

Further, the subsequent section is represented as (C) area. The area (C) is tentatively referred to as a section for performing “constant voltage charging”, and the meaning of this “constant voltage charging” is the charger 813 (FIG. 8) and the joining board 814 (FIG. 8) (charging device 1001 (FIG. 10)). ) Does not mean that a constant voltage is applied to the high-voltage assembled battery 811 (FIG. 8), “the storage battery cell having the characteristic line 326 (characteristic line 316) having the smallest storage capacity and the highest charging voltage (V _MAX ) This means that the applied voltage is adjusted so that the applied voltage keeps a predetermined charging voltage.

In the (C) region, which is the section of “constant voltage charging”, a voltage higher than a predetermined charging voltage is not applied. This also corresponds to the characteristic line 326 in FIG.
However, as described above, since the charging voltage of the storage battery cell is the sum of the open voltage and the voltage increase due to the product of the internal resistance and the storage current, there is a difference between the predetermined charging voltage and the open voltage. Even when the charging voltage shifts to “constant voltage charging”, the stored current decreases, but the current continues to flow. With this current, charging is continued while there is room in the storage capacity, and the storage capacity is gradually increased. Accordingly, the open circuit voltage further gradually increases, and the stored current further decreases by the amount that the difference from the predetermined charging voltage decreases. The above represents a situation where the time decreases with the time of Ic (t) in FIG. In FIG. 3A, the voltage represented by the characteristic line 326 is a charging voltage and does not represent an open circuit voltage.

The storage battery cell having the characteristic line 316 with the highest charging voltage (V _MAX ) is the storage battery cell having the most deteriorated storage capacity, but the storage battery cell having the characteristic line 311 with the lowest charging voltage (V _MIN ) It is a storage battery cell that is least deteriorated in terms of capacity. In this way, both relatively small and large storage capacities are mixed, but since all of these storage battery cells are connected in series, the storage current is the same, and as a result, the storage capacities are all The same amount increases in the storage battery cells. This is also true for the (E) region and (C) region in FIGS. 3 (a) and 3 (b). The variation in capacity characteristics due to the deterioration of each storage battery cell, when all the storage battery cells are connected in series, has the same stored capacity, and instead appears as a difference in open circuit voltage. As a result, the storage battery cell having the highest charging voltage (V _MAX ) characteristic line 316 in the (E) region of FIG. 3A shows the characteristic line 326 in the (C) region. In addition, in the (E) region, the storage battery cell having the characteristic line 311 having the lowest charging voltage (V _MIN ) exhibits the characteristic (line) 321 in the (C) region. Moreover, each characteristic of the storage battery cell which has the characteristic of those middle is represented to the characteristic line 322-325 and the low charging voltage in order.

  As described above, also in the region (C), each storage battery cell has the same amount of storage capacity due to the same storage current. The open circuit voltage of each storage battery cell increases as the storage capacity increases. However, in the (C) region, because of the above-described “constant voltage charging”, the increase of the open circuit voltage of each storage battery cell is due to the decrease of the storage current. There is almost no change in the charging voltage, offsetting the decrease in the internal voltage due to the product with the internal resistance. This situation is the same at the point 332 which is the start of the region (C) and also at the point 333 where the storage current decreases and hardly flows. Therefore, as shown in FIG. 3 (a), even if there is a variation in the characteristics of each storage battery cell in the (C) region, each storage battery cell gradually increases the storage capacity in the same way, The charging voltage keeps almost the voltage at the point 332 which is the start of the (C) region. As described above, the charging voltage-storage capacity characteristic or the charging voltage-storage time characteristic of each storage battery cell in the region (C) of FIG.

In the region (C) of FIG. 3 (a), the storage battery cell having the characteristic line 326 having the highest charging voltage (V _MAX ) continues to flow the storage current even if it is a little, gradually increasing the storage capacity, When the open circuit voltage rises and finally reaches a predetermined charging voltage, the voltage difference disappears, so that the stored current does not flow. Incidentally, it is determined that "power storage current does not flow" by equal to or less than a predetermined current value I _S. The section after this is defined as (S) area.
As a result, the storage current does not flow in all the storage battery cells connected in series. Each storage battery cell of the characteristic lines 321 to 325 in the region (C) of FIG. 3A has a surplus power storage capacity, but the power storage capacity no longer increases in “constant voltage charging”. The storage capacities of the storage battery cells having the characteristics of the characteristic lines 321 to 326 at this time are all substantially the same. That is, only the same storage capacity as that of the storage battery cell having the smallest storage capacity, that is, the most deteriorated battery capacity can be secured.

From the above, when a plurality of storage battery cells are connected in series and used as an assembled storage battery, the storage capacity characteristics of the most deteriorated storage battery cells become dominant. Important and further measures to prevent deterioration are required.
The assembled battery is configured by connecting a plurality of storage battery cells in series as described above, but by using a plurality of assembled batteries configured in this way, the number of storage battery cells is further increased. Many battery packs may be configured. In such a case, both will be referred to as assembled batteries.

By the way, if you continue to charge a storage battery cell that has deteriorated and has a low storage capacity value and a high open-circuit voltage or charge voltage, the storage battery cell has a low storage capacity value and a low open-circuit voltage or charge voltage. Compared with the case, the temperature rise is more likely to occur. Therefore, in order to prevent further deterioration of the storage battery cell that has been deteriorated, it is desirable to cool the battery cell and avoid an increase in temperature.
Further, in the state of the (S) region, even if the storage battery cell having a large storage capacity value and having not deteriorated is in the (S) region, the storage capacity is sufficient and the open circuit voltage is low. In the (S) region, there is a difference in open-circuit voltage between the unit cell battery that has deteriorated and the storage battery cell that has not progressed. Therefore, in order to find and deal with a battery cell that has deteriorated, voltage detection is performed for every battery cell.
In addition, storage battery cells that have not deteriorated are used with a margin in the storage capacity, but when the storage battery cells are used in series, the characteristics of the storage battery cells that are most deteriorated are dominant. Therefore, it is most effective to preferentially treat storage battery cells that have deteriorated.

((3) Temperature variation and characteristic variation of battery pack)
When a plurality of storage battery cells are arranged and used in the assembled storage battery, the temperature of the storage battery rises as the load increases. At this time, even when the cooling air is sent from the surroundings by a fan, there are places where the cooling air hits well and places where it is difficult to hit, and therefore, temperature variation occurs between the storage battery cells in the assembled battery. Therefore, when used in such a state, even storage battery cells having substantially the same characteristics in the initial stage have different degrees of deterioration over a long period of time, resulting in variations in characteristics such as storage capacity values. If the cooling method is not particularly devised, this variation gradually increases. As described above, when the storage battery cells are connected in series to form an assembled storage battery, the characteristics of the most deteriorated storage battery cells become dominant, and the characteristic variation has a great influence. In addition, although there are differences in the shape of the storage battery cell such as a round battery or a square battery, the situation in which the above-described temperature variation or characteristic variation occurs is the same in any case.

((4) Cooling air and battery cell temperature)
FIG. 4 shows the state of the cooling effect when cooling air is applied to the assembled battery 40 in a situation where a plurality of storage battery cells 46A and 46B are arranged in the assembled battery 40 and the SOC and deterioration state of each storage battery cell are different. It is shown as a schematic view seen from the upper surface of the assembled battery 40.
The assembled battery 40 is disposed in a duct 45, and cooling air 41 is supplied to the plurality of storage battery cells 46 </ b> A and 46 </ b> B from between the ducts 45 to be exhausted 42 and ventilated to the outside of the duct 45. The storage battery cells 46A and 46B are fixed by the support 47.
The plurality of storage battery cells 46A and 46B are electrically connected in series to form the assembled storage battery 40. When the characteristics and deterioration of each storage battery cell are substantially the same, a charging current (also a storage current). Are the same, the state of heat generation of each storage battery cell during charging is substantially the same.

In the above situation, in the arrangement of the storage battery cells shown in FIG. 4, the cooling air 41 is likely to hit the storage battery cell 46 </ b> A located at the center and is difficult to hit the storage battery cell 46 </ b> B located at the end. Therefore, since the storage battery cell 46A is “cooled well”, the characteristics of the storage battery cell are less deteriorated. Moreover, since the storage battery cell 46B is difficult to cool, the characteristics of the storage battery cell are likely to deteriorate.
FIG. 4 is a schematic diagram, and the number of storage battery cells 46A and 46B and the shape of the duct 45 can be various.

  FIG. 5 shows an example in which a region where a plurality of storage battery cells 46A and 46B are arranged in an assembled battery 40 having the same configuration as FIG. 4 is divided into area 1 (51), area 2 (52), and area 3 (53). Is shown. If the amount of cooling air hit varies depending on the location where each battery cell is installed, and the way of dealing with it changes, it is effective to detect and manage the location of each battery cell from the perspective of an area identified by a number, etc. Is.

5 and 4, the assembled battery 40, the storage battery cells 46 </ b> A and 46 </ b> B, the duct 45, the support body 47, the cooling air 41, and the exhaust 42 are the same, and further description is omitted. In FIG. 5, reference numerals 51, 52, and 53 represent area 1, area 2, and area 3, respectively. Thermometers 541, 542, and 543 measure the temperatures of area 1, area 2, and area 3 as necessary, and are used when detecting the temperature of each area.
As described later, when detecting storage battery voltage or applying cooling air, it is effective to divide into areas, average the voltage for each area, and intensively cool areas showing high voltage It is.

In some cases, a partition wall is provided between the areas 1, 2, and 3, and recognition as an area is performed separately, but a partition wall is not particularly provided.
Note that FIG. 5 is a schematic diagram, and the method of dividing areas, the number of areas, the number of thermometers, and installation positions can be variously taken.

((5-1) Cooling air first control method, variable rectifying plate method)
FIGS. 6A and 6B are diagrams showing a first control method of cooling air. 6 (a) and 6 (b), the assembled battery 40, the storage battery cells 46A and 46B, the duct 45, the support body 47, the cooling air 41, and the exhaust 42 are the same as those shown in FIGS. Further explanation is omitted.
6A and 6B show a system in which the cooling air 41 is controlled by the current plate 69 (69A, 69B) in the duct 45 in which the assembled battery 40 is housed.

  FIG. 6A shows a normal time when no control is performed, and the rectifying plate 69 (69 </ b> A) is oriented so as not to act on the cooling air 41. Therefore, the cooling air 41 is likely to hit the storage battery cell 46A located at the center and is difficult to hit the storage battery cell 46B located at the end. As a result, since the storage battery cell 46A “cools well”, the characteristics of the storage battery cell 46A are less deteriorated. Moreover, since the storage battery cell 46B is hardly cooled, the characteristics of the storage battery cell 46B are in a state where deterioration is likely to proceed.

In FIG. 6B, the current plate 69 (69B) is opened to some extent. As a result, the cooling air 41 is likely to hit the storage battery cell 46B located toward the end, and is less likely to hit the storage battery cell 46A located in the center. This is to detect the voltage of all the storage battery cells, and when it is determined that the deterioration of the storage battery cell 46B located toward the end is relatively advanced, the cooling battery 50B is likely to hit the storage battery cell 46B. Shows the case of control.
Note that the position where the cooling air can easily hit can be changed depending on the angle of the current plate 69 (69A, 69B). Further, the number and shape of the rectifying plates 69 (69A, 69B), or the installation positions can be variously taken.

((5-2) Cooling air second control method, slit opening / closing method)
FIG. 7 is a diagram showing a second control method of the cooling air 41. In FIG. 7, the assembled battery 40, the storage battery cells 46A and 46B, the duct 45, the support 47, the cooling air 41, and the exhaust 42 are the same as those shown in FIGS. To do.
In FIG. 7, a plurality of slits 79 are provided on the side surface of the assembled battery 40. Depending on whether the slit 79 is opened / closed or to which position the slit 79 is moved, the flow of the cooling air 41 changes, and a control system is selected to select a storage battery cell to be cooled preferentially.
It should be noted that the number and shape of the slits 79 and the installation position can be various.

(Flowchart of storage battery charging method in this embodiment)
Since the characteristics of the storage battery, the charging method, the cooling air control method, and the like necessary for the description of the flowchart of FIG. 1 have been individually outlined in the above (1) to (6), returning to FIG. The flowchart which shows the method of control when charging the battery of embodiment is demonstrated.
According to this flowchart, plug-in charging using a household power source is performed.
[0] First, it starts from connecting a charging device to the charging port of the car (step S0).

[1] When the charging device is connected, it is determined from the standard and shape of the connecting device whether it is plug-in charging using a household power source or rapid charging using a dedicated device (step S1).
As described above, plug-in charging using a household power source is charging performed using a low-capacity power source of 100 V or 200 V, which is a general household power source. On the other hand, rapid charging is performed using a dedicated device different from the home power supply. Compared to plug-in charging using a household power supply, the storage battery is a rapid charging method in which a high voltage is applied and charging is completed in a short time with a large current.
In step S1, when it is determined that rapid charging is performed (No), the following plug-in charging is not performed, and the flow process is terminated.
If it is determined in step S1 that a charging device for plug-in charging is connected to the charging port (Yes), the process proceeds to step S2.

[2] In step S2, charging of the battery pack 811 (FIG. 8) is started at an appropriate voltage by the charger 813 (FIG. 8) and the joining board 814 (FIG. 8). Therefore, charging is started for all the storage battery cells constituting the assembled storage battery all at once. As each storage battery cell is charged, the storage capacity increases and the open circuit voltage increases.

[3] Among the storage battery cells, the most deteriorated storage battery cell has the highest open-circuit voltage or charge voltage first. Then, it is determined whether or not the cell having the highest charging voltage V _MAX among the storage battery cells has reached a predetermined charging voltage (step S3). This determination is made by the charger 813 (FIG. 8) and the joining board 814 (FIG. 8).
If not reached (No), the above-described charging is continued. If it has reached (Yes), the process proceeds to step S4.

[4] accumulator cells of the highest charge voltage V _MAX among the battery cells, when reaching the predetermined charging voltage, battery capacity the battery cell already means that approached SOC 100%. If the charging is continued in the same manner, the temperature of the storage battery cell having the highest charging voltage V _MAX increases rapidly, and the deterioration of the storage battery cell is promoted.
Therefore, the charging voltage of the storage battery cell having the highest charging voltage V _MAX is switched to “constant voltage charging” that maintains the predetermined charging voltage (step S4).

[5] If "constant voltage charging" is maintained while maintaining a predetermined charging voltage, there is a difference between each open voltage of each storage battery cell and each charging voltage of each storage battery cell in "constant voltage charging". The charging current (storage current) continues to flow to some extent. Eventually, the open-circuit voltage of each storage battery cell increases and approaches each charging voltage applied to each storage battery cell in “constant voltage charging”, so that the charging current (storage current) decreases. When the storage battery cell that is most deteriorated and has the highest charging voltage V _MAX becomes approximately SOC 100%, the storage current (charging current) approaches approximately zero. Actually, as the determination criterion, the charging current is compared with a predetermined current value (step S5).
If the predetermined current value has not been reached (No), the above-described “constant voltage charging” is continued. If it has reached (Yes), it is determined that the SOC has reached 100%, and the process proceeds to step S6.

[6] Charging is terminated, and the temperature (T _BAT ) of each storage battery cell or each storage battery cell is detected by thermometers 541 to 543 (FIG. 5) or the like (step S6).

[7] The temperature of the battery cell having the lowest temperature among the storage battery cells or the storage battery cells in each area is _set as T _BATMIN , and T _BATMIN is compared with a predetermined temperature (step S7).
If T _BATMIN is compared with the predetermined temperature, and T _BATMIN is lower than the predetermined temperature (No), the temperature of the outside air is very low, and the internal resistance of the storage battery cell may be abnormally high Is expensive. Then, in the following flow processing after step S8, there is a high possibility of erroneous determination and erroneous processing thereby, so the flow after step S8 does not proceed and the entire flow processing ends.
If T _BATMIN is compared with a predetermined temperature and T _BATMIN is higher than the predetermined temperature (Yes), it is determined that there is little possibility of erroneous determination due to the temperature of the outside air, and the process proceeds to the next step S8.

[8] The voltage of all the storage battery cells is detected (step S8). In addition, this is for grasping | ascertaining the condition of the characteristic deterioration of all the storage battery cells. Then, the process proceeds to next Step S9.

[9] Each storage battery cell voltage detected in step S8 is averaged for each cooling area (step S9). Then, the process proceeds to the next step S10.

[10] A process of comparing the area minimum value of the storage battery cell voltage with the average value for each area is performed (step S10). Then, the process proceeds to the next step S11.

[11] In the comparison process between the area minimum value of the storage battery cell voltage obtained in step S10 and the average value for each area, it is determined whether or not there is a difference of a predetermined value or more (step S11).
If there is no difference equal to or greater than the predetermined value (No), it is determined that there is no need to newly adjust the capacity deterioration suppression control, and the entire flow process is terminated.
If there is a difference greater than or equal to the predetermined value (Yes), the process proceeds to the next step S12.

[12] By detecting an area that is greater than or equal to a predetermined difference, the flow path is such that a large amount of cooling air is supplied to an area (region) where the detection voltage is high and at least the supply is good to an area (region) where the detection voltage is low Is changed (step S12). This is to prevent or reduce further deterioration by preferentially cooling, assuming that the battery cell with a high voltage has been deteriorated.
This completes the overall flow process.

The above flowchart is a control method for detecting concentrated storage battery cells and cooling them in a concentrated manner with priority given to those that are progressing while dividing areas.
By performing the above, it is possible to equalize the characteristics and performance by simplifying the cooling of the remaining storage battery cells while preventing further deterioration of the deteriorated storage battery cells. Therefore, it is considered that the SOC variation of the storage battery cells is reduced in the process of using the electric vehicle.

When plug-in charging is performed, V _MAX or the like is not detected if the storage battery cannot be charged to near SOC 100% due to the rated conditions (voltage and current) of the charger. This is because the specification for charging to SOC 100% as a vehicle control is premised.

  In step S6 in the flowchart, the temperature of each storage battery cell or the storage battery cell temperature for each area is measured. In step S7, it is determined whether or not the lowest storage battery cell temperature is equal to or lower than a predetermined temperature. . The reason why steps S6 and S7 are necessary will be supplementarily described. Depending on the season, the battery temperature may be very low (for example, in a state of 0 ° C. or lower in winter) due to the influence of the outside air temperature, and the internal resistance of the storage battery may be abnormally high. In this case, the deterioration due to the voltage of the storage battery cell after step S8 may be determined by the difference in the internal resistance of the battery due to the current temperature of each storage battery cell rather than the characteristic difference due to the deterioration state of each storage battery cell. Yes, there is a high possibility of erroneous determination. Therefore, if it is determined in steps S6 and S7 that the battery cell temperature is lowest is lower than the predetermined temperature, it is determined that there is a high possibility of erroneous determination in the battery cell voltage, and the process proceeds to step S8 and subsequent steps. First, the whole flow process is complete | finished, without detecting a storage battery cell.

  In addition to the method of directly measuring the temperature described above, the condition that does not proceed to step S8 and thereafter and does not detect the storage battery cell is not only the method of directly measuring the temperature, but also the time zone when a low temperature is predicted in advance, such as the dawn at the time of cold. Depending on the situation, the battery cell voltage may not be detected.

(Electric system including high-voltage assembled battery in this embodiment)
FIG. 8 is a functional block diagram of an electric system including the high-voltage assembled battery 811 in the present embodiment. The high-voltage assembled battery 811 is an assembled battery in which a plurality of storage battery cells are connected in series and performs high-voltage input / output. The plug input device 812 receives a 100V or 200V AC power supply by inserting a power plug 902 (FIG. 9) from a household power supply 903 (FIG. 9) having a low storage capacity of 100V or 200V. The charger 813 receives AC power from the plug input device 812, determines whether it is 100V or 200V, plug input or quick charge, and converts it to a predetermined appropriate DC voltage (DC power) accordingly. A DC voltage (DC power) output from the charger 813 is supplied to a high-voltage assembled battery 811 through a junction board 814. The joining board 814 includes an equalization circuit so that a plurality of storage battery cells constituting the high-voltage assembled storage battery 811 have the same characteristics. The high-voltage DC power stored in the high-voltage assembled battery 811 serves as an energy source for various devices in the electric system of the electric vehicle 901 (FIG. 9).

A PDU (Power Drive Unit) 815 is provided between a traveling motor 816 such as a three-phase AC motor and a high voltage storage battery 811. The PDU 815 obtains DC power from the high-voltage assembled battery 811 and converts the DC power into three-phase AC power to drive the traveling motor 816. Further, the PDU 815 converts the regenerative power collected during the regenerative braking of the traveling motor 816 into DC power, and charges the high-voltage assembled battery 811. The PDU 815 controls input / output of electric power from the high voltage storage battery 811 in this way.
In addition, high-voltage direct current power is supplied from the high-voltage assembled battery 811 to various loads 817 such as air conditioner heaters and compressors (not shown).

  In addition, in an electric system that requires a low voltage (approximately 12V), a low-voltage DC power is supplied to a storage battery fan 819 (for cooling the high-voltage storage battery 811) via a step-down circuit (actually a DC / DC converter) 818, and a storage battery ECU ( Electronic control unit) 821. Further, the low-voltage DC power of the step-down circuit 818 is supplied to the 12V storage battery 820, and the ECU-related load (motor ECU, A / C (Air Conditioner) ECU, general ECU, etc. (not shown)) 822 passes through the 12V storage battery 820. A stable 12V low voltage DC power is supplied. In addition, since the apparatus which passed through these 12V storage batteries 820 is not directly related to the invention of this application, detailed description is abbreviate | omitted.

FIG. 9 shows an outline of how the main devices of the electric system shown in FIG. 8 are mounted and arranged in the electric vehicle 901 and charged from a household power source.
A high-voltage storage battery 811 is provided in the rear portion from the center of the electric vehicle 901, and a charger 813, a junction board 814, a plug input device 812, a step-down circuit 818, and a storage battery fan 819 are disposed around the high-voltage storage battery 811. In addition, a traveling motor 816 and a PDU 815 are disposed at the front of the vehicle body of the electric vehicle 901. Each of the above devices is connected and related by the electrical system shown in FIG.

  In FIG. 9, a power plug 902 drawn from an AC 100V or 200V household power supply 903 installed on the side wall 904 is inserted into a plug input device 812 of an automobile 901, electrically connected, and charged. Show.

As described above, according to the embodiment of the present invention, it is possible to derive a storage battery cell group having relatively simple capacity deterioration with a simple configuration.
For this reason, it is possible to prevent the output restriction from starting to be applied earlier than the restriction by the SOC calculated by the vehicle (electric vehicle) due to the storage battery cells in which the SOC varies.
Moreover, the consumption current (consumption energy) required for storage battery cell voltage equalization can be suppressed.
In addition, according to the present invention, early output limitation due to capacity variation suppression is prevented, leading to improved drivability (power performance), cruising distance (improves power consumption), and life.
In addition, since it is possible to deal with intensive cooling and the like for storage battery groups that have relatively deteriorated capacity, it is possible to prevent further progress and expansion of deterioration, and between each storage battery cell while using an electric vehicle. This has the effect of equalizing that the variation in
Further, since it is a method of knowing where the deterioration has occurred relatively, it is not necessary to store past history, and a large-capacity memory becomes unnecessary.
There are various effects as described above.

  The invention of this application is intended only for the case of plug-in charging from a household power source. There is a process of charging the high-voltage storage battery 811 at the time of quick charging or at the time of recovery of the regenerative power described above, but it is out of the scope of the present invention.

The invention of the present application focuses on electric vehicles, but it is effective from the viewpoint of preventing capacity variation of a storage battery and improving the life of a hybrid vehicle such as a PHEV vehicle (Plug-in Hybrid Electric Vehicle) or a fuel cell vehicle. It is a technique.
Moreover, it can be applied not only to automobiles but also to ships, airplanes, railway vehicles and the like.

40 battery pack 45 duct 46A, 46B, 1011, 1012, 1013, 1014, 1015, 1016, battery cell 47 support body 51, 52, 53 area 541, 542, 543 thermometer 69A, 69B rectifier plate 79 slit 811 set of high pressure Storage battery (assembled storage battery)
812 Plug input device 813, 1001 Charger, charging device 814 Bonding board (including voltage detection device)
815 PDU
816 Motor for driving 817 Load 818 Step-down circuit 819 Storage battery fan (capacity deterioration suppressing device)
820 12V storage battery 821 storage battery ECU
822 ECU-related load 901 Electric vehicle 902 Power plug 903 Household power supply 904 Side wall 1021, 1022, 1023, 1024, 1025, 1026 Voltmeter, (Voltage detection device)

Claims (9)

A method for detecting a capacity-degraded storage battery cell group of an assembled storage battery composed of a plurality of storage battery cells having a voltage characteristic in which the voltage rises following the increase in the storage capacity,
Charge until any storage battery cell of the assembled battery reaches the upper limit voltage determined in the voltage region where the voltage rises following the increase in the storage capacity,
The storage battery cell that has reached the upper limit voltage after the charge is charged so as to maintain the upper limit voltage,
After charging until the charging current value becomes a predetermined current value or less, the voltage of all the storage battery cells is detected,
A method for detecting a capacity-degraded storage battery cell group, comprising comparing a voltage average value for each area in which the storage battery cells are arranged with each other to detect a relatively degraded storage battery cell group.   The capacity deterioration storage battery cell group detection method according to claim 1, wherein capacity deterioration suppression control for preferentially distributing the cooling air to the storage battery cell group is performed.   The capacity deterioration storage battery cell group detection method according to claim 2, further comprising a rectifying plate having a variable angle in capacity deterioration suppression control for distributing cooling air with priority given to the capacity deterioration storage battery cell group.   The capacity deterioration storage battery cell group detection method according to claim 2, further comprising a slit that can be opened and closed or moved in capacity deterioration suppression control for distributing cooling air with priority given to the capacity deterioration storage battery cell group.   The method for detecting a capacity-degraded storage battery cell group according to any one of claims 1 to 4, wherein the charging is plug-in charging using a household power source. The detection method of the capacity deterioration storage battery cell group of the said assembled battery is not performed when a quick charger is connected, The detection method of the capacity deterioration storage battery cell group of any one of Claim 1 thru | or 5 characterized by the above-mentioned. Method. The method for detecting a capacity deteriorated storage battery cell group according to any one of claims 1 to 6 , wherein the method for detecting the capacity deteriorated storage battery cell group of the assembled battery is not performed when the temperature is lower than a predetermined temperature. The method for detecting a capacity-degraded storage battery cell group according to any one of claims 1 to 6 , wherein the method for detecting the capacity-deteriorated cell group of the battery pack is not performed during a predetermined time period. . In an electric vehicle that performs plug-in charging using a household power supply,
A charging device for charging electricity to an assembled battery composed of storage battery cells; and
A voltage detection device for detecting a voltage of the storage battery cell group in the assembled battery;
A capacity deterioration suppressing device that distributes cooling air, and
Until any storage battery cell of the assembled storage battery reaches the upper limit voltage determined in the voltage region where the voltage rises following the increase in the storage capacity of the assembled storage battery by the charging device and the voltage detection device Charge
The storage battery cell that has reached the upper limit voltage after the charge is charged so as to maintain the upper limit voltage,
After charging until the charging current value becomes a predetermined current value or less, the voltage of all the storage battery cells is detected,
Detecting a battery cell group that is relatively deteriorated by comparing voltage average values for each area where the battery cells are arranged,
Storage battery and performing by said voltage detecting device and the capacity deterioration prevention device, to the storage battery cell group in the set battery, the capacity deterioration suppression control of cooling wind distribution in favor of capacity deterioration battery cell group Cell group capacity deterioration suppression control device.

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