JP2010170942A - Battery pack, method for manufacturing the same, battery pack, battery pack module, vehicle mounting the same, and battery mounting equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery pack and a method for manufacturing the same capable of suppressing generation of dispersion caused by high rate deterioration of each unit cell in the battery pack, and to provide a battery pack, a battery pack module, a vehicle mounting the same, and battery mounting equipment. <P>SOLUTION: In the battery pack formed by assembling a plurality of secondary batteries, the amount of an electrolyte of a secondary battery arranged in a region raising temperature during use out of the plurality of secondary batteries is increased than that of an electrolyte of a secondary battery arranged in a region lowering temperature during use out of the plurality of secondary batteries. In the battery pack module having a battery pack formed by assembling a plurality of secondary batteries and a charging state control part controlling the charging state of each secondary battery of the battery pack, the charging state control part lowers the charging state of a secondary battery arranged in a region raising temperature during use than that of a secondary battery arranged in a region lowering temperature during use. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention provides, for example, a battery pack and a method for manufacturing the battery pack, and a battery pack for charging the battery pack (unit battery) of a plurality of secondary batteries such as lithium ion secondary batteries and connecting them together. The present invention also relates to an assembled battery module having a charge state control unit that controls the state, and further to a battery pack, an assembled battery, or a vehicle or battery-equipped device equipped with the assembled battery module. More specifically, by forming a cooling medium flow path, an assembled battery having a slightly different temperature during use depending on the individual secondary battery, a method for manufacturing the assembled battery, a battery pack, an assembled battery module, a vehicle or battery mounted with the assembled battery It relates to on-board equipment.

  Conventionally, a plurality of unit cells are connected to each other and used as a high voltage / large capacity assembled battery. In such a case, normally, although the assembled battery is charged and discharged as a whole, there is some variation in the capacity of each unit cell. Continued use with variations may cause overdischarge or overcharge depending on the unit cell. For this reason, various systems for monitoring and equalizing the voltage value of each unit cell have been proposed.

  For example, the remaining capacity is detected, and a process of charging or discharging each cell so as to reduce the difference is performed. Furthermore, Patent Document 1 discloses a technique for detecting and controlling the voltage between terminals of each unit cell. According to this technique, it is said that the variation can be equalized only by discharging a high voltage value. Alternatively, Patent Document 2 discloses a technique for determining a target value of SOC (State Of Charge) of a battery pack based on the amount of voltage variation. And it is supposed that a capacity | capacitance adjustment suitable for the driving | running | working frequency of a vehicle can be performed.

JP 2001-218376 A JP 2007-87863 A

  However, each of the above-described conventional adjustment methods adjusts the assembled battery after the variation, and does not suppress the occurrence of the variation itself. In particular, depending on the driving mode, high-rate deterioration due to repeated high-rate charge / discharge is inevitable. Furthermore, it has been found that the progress of this high rate deterioration is slightly different depending on the usage environment of each unit cell. Due to variations in the degree of deterioration of each unit cell, there has been a problem that the voltage and remaining capacity further vary.

  The present invention has been made to solve the problems of the above-described conventional assembled battery. That is, the problem is that an assembled battery that can suppress the occurrence of variations due to high-rate deterioration of each battery cell, a manufacturing method thereof, a battery pack, an assembled battery module, a vehicle on which the battery is mounted, and a battery mounted To provide equipment.

  The assembled battery of the present invention, which has been made for the purpose of solving this problem, is an assembled battery in which a plurality of secondary batteries are combined, and is disposed in a region of the plurality of secondary batteries that becomes colder during use. Compared with the amount of electrolytic solution in the battery, the amount of electrolytic solution in the plurality of secondary batteries disposed in the region where the temperature is higher during use is larger.

  The inventor has found that the high rate deterioration of the unit cell is faster in the low temperature environment than in the high temperature environment, and faster in the case where the amount of the electrolyte solution is larger than that in which the amount of the electrolyte solution is small. In the assembled battery of the present invention, the amount of electrolyte used in a low temperature environment is smaller, and the amount of electrolyte used in a high temperature environment is larger. Variations in progress are canceled out each other. Therefore, the assembled battery can suppress the occurrence of variations due to the high rate deterioration of each unit cell.

  Alternatively, the assembled battery module of the present invention is an assembled battery module having an assembled battery obtained by combining a plurality of secondary batteries, and a charge state control unit that controls the charge state of each secondary battery of the assembled battery, The charge state control unit has a higher temperature among the plurality of secondary batteries when used, compared to a state of charge of the plurality of secondary batteries disposed in a region where the temperature is lower during use. This lowers the state of charge in those arranged in the region.

  The present inventor has also found that the progress of high-rate deterioration of the unit cell is faster when the cell is lower than when the state of charge is high. According to the assembled battery module of the present invention, it is possible to cancel the variation in the progress of the high-rate deterioration due to the temperature during use, depending on the state of charge. Therefore, the assembled battery module can suppress the occurrence of variation due to the high rate deterioration of each unit cell.

In addition, the present invention provides an assembled battery or an assembled battery module as an assembled battery pack having an inlet for taking in a cooling medium for cooling a plurality of secondary batteries and an outlet for discharging the cooling medium. Is a region including the battery closest to the inlet in the assembled battery, and the region that becomes hotter during use extends to other regions in the assembled battery.
In the case of a battery pack configured to take in the cooling medium from the inlet and discharge from the outlet, the battery in the region including the battery closest to the inlet in the assembled battery is well cooled by the cooling medium taken in from the inlet. As a result, it becomes cooler when used.

Furthermore, in the present invention, the charge state control unit performs control to equalize the voltage of each secondary battery by discharging a secondary battery having a high charge state, and is included in a region where the temperature becomes lower during use. It is desirable that the secondary battery is not discharged or only discharged to a higher charge state than the secondary battery included in a region that becomes hotter during use.
In this way, the state of charge of the secondary battery arranged in the region that becomes colder during use is higher than the state of charge in the battery that is arranged in the region that becomes hotter during use. It is easy to do.

Furthermore, in the present invention, with respect to the assembled battery in which a plurality of secondary batteries are arranged in two rows, a cooling medium is introduced from the opposite side of the second row in the secondary battery at one end of the first row, The cooling medium is allowed to flow from one end to the other end on the opposite side of the second row in each secondary battery of the first row, folded at the other end of the first row and the second row, and the second row Cooling medium that allows a cooling medium to flow from the other end toward one end on the opposite side of the first row in the secondary battery and discharges the cooling medium from the opposite side of the first row in the secondary battery at one end of the second row It is desirable that the path is formed as any one of (A) to (F) below.
In any of these configurations, it is possible to suppress the occurrence of variation due to the high rate deterioration of each unit cell.

(A) When the first row is divided into a section on one end side and a section on the other end side, the amount of the electrolyte of the secondary battery belonging to the section on one end side is small, and the other end side of the first row An assembled battery having a large amount of electrolyte solution of the secondary battery belonging to the secondary battery belonging to the second row.
(B) When the second row is divided into a section on one end side and a section on the other end side, the amount of the secondary battery belonging to the section on the other end side is large, and the secondary battery belonging to the first row A battery and a battery pack having a small amount of electrolyte solution of a secondary battery belonging to one end of the second row.
(C) The first row is divided into two sections, one end side section and the other end side section, and the second row is divided into a section on one end side at a position closer to one end side than the bisection portion of the first row; The amount of electrolyte in the secondary battery belonging to the section on the one end side of the first row and the secondary battery belonging to the section on the one end side of the second row is small when divided into the section on the other end side , A secondary battery belonging to a section on the other end side of the first row, and an assembled battery having a large amount of electrolyte solution of a secondary battery belonging to the other end side of the second row.

(D) The charge state of the secondary battery belonging to the one end side section when the first row is divided into the one end side section and the other end side section is high, and belongs to the other end side of the first row An assembled battery module that lowers the charge state of the secondary batteries and the secondary batteries belonging to the second row.
(E) The secondary battery belonging to the first column is low and the charge state of the secondary battery belonging to the segment on the other end side is low when the second column is divided into the segment on the one end side and the segment on the other end side. And the assembled battery module which makes high the charge condition of the secondary battery which belongs to the one end side of a 2nd row | line.
(F) The first row is divided into two sections, one end side section and the other end side section, and the second row is divided into a section on one end side at a position closer to one end side than the bisection portion of the first row; The charging state of the secondary battery belonging to the section on one end side of the first row and the secondary battery belonging to the section on one end side of the second row when divided into two sections to the other end side section is low, The assembled battery module which makes high the charge condition of the secondary battery which belongs to the area of the other end side of the 1st row, and the secondary battery which belongs to the other end side of the 2nd row.

  The present invention also relates to a method of manufacturing an assembled battery in which a plurality of secondary batteries are combined. The secondary batteries having different amounts of electrolyte contained therein are prepared, and a secondary battery having a large amount of electrolyte is prepared. The present invention extends to a method of manufacturing an assembled battery in which a secondary battery with a small amount of electrolyte is arranged in a region where the temperature is lower when used, and a secondary battery with a smaller amount of electrolyte is placed in a region where the temperature is higher when used.

  Furthermore, the present invention extends to a vehicle equipped with any one of the above assembled batteries, battery packs or assembled battery modules. Further, the present invention extends to battery-equipped devices equipped with any of the above assembled batteries, battery packs, or assembled battery modules.

  According to the assembled battery and the manufacturing method thereof, the battery pack, the assembled battery module, the vehicle equipped with the assembled battery, and the battery-equipped device according to the present invention, it is possible to suppress the variation due to the high rate deterioration of each unit cell in the assembled battery. .

It is explanatory drawing which shows the structure of an assembled battery. It is explanatory drawing which shows the temperature of each single battery at the time of use of an assembled battery. It is a graph which shows the example of a high rate pulse. It is a graph which shows the relationship between temperature and high-rate degradation. It is a graph which shows the relationship between electrolyte amount and high-rate deterioration. It is a graph which shows the relationship between SOC and high rate deterioration. It is explanatory drawing which shows the example of the division of an assembled battery. It is explanatory drawing which shows an assembled battery module. It is explanatory drawing which shows the example of the division of an assembled battery. It is explanatory drawing which shows the example of the division of an assembled battery. It is explanatory drawing which shows the vehicle which uses an assembled battery. It is explanatory drawing which shows the example of the battery mounting apparatus which uses an assembled battery.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best mode for embodying the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to an assembled battery in which a plurality of single cells are combined.

  The assembled battery 10 of this embodiment is an assembled battery 10 that is used by being mounted on, for example, an automobile. Here, as shown in FIG. 1, a total of 56 unit cells A-1 to A-56 are arranged in two rows of 28 cells. The flat cells of the cells in each row are opposed to each other, and the narrow surfaces of the cells are visible in the figure. Further, two rows of 28 unit cells are arranged with their side surfaces facing each other.

  Further, in this embodiment, as shown in FIG. 1, an air passage 12 that makes a round of the outer periphery of the assembled battery 10 is formed. Since the assembled battery 10 generates heat to some extent when used, it is cooled by flowing air through the air passage 12. During use of the battery pack 10, air is constantly flowing through the air passage 12 as indicated by a solid arrow W in the figure.

  In this embodiment, for the sake of explanation, numbers are given to the single cells along the direction of the air flow as shown in FIG. That is, the unit cell in the upper right corner in the figure is designated as A-1, and from there, it is designated as A-2, A-3,. Further, the left side of A-28 in the figure is A-29, and from there, it is A-30, A-31,. Further, the column including the single cells A-1 to A-28 on the right side in the drawing is referred to as column 1, and the column including the single cells A-29 to A-56 on the left side in the drawing is referred to as column 2. In each row, the upper side in the figure (the side where the cells A-1 and A-56 are arranged) is one end side, and the lower side in the figure (the side where the cells A-28 and A-29 are arranged). ) On the other end side.

  Each unit cell included in the assembled battery 10 of the present embodiment is a flat sealed lithium ion secondary battery. Furthermore, in this embodiment, all the single cells are used in series with each other. However, the battery numbers given here are for convenience and do not indicate the order of electrical connection.

  In the air passage 12 of the assembled battery 10 according to this embodiment, an inlet 13 is provided at a location in the upper right corner of the cell A-1 in the upper right corner of FIG. Moreover, the outlet 14 is provided in the upper left corner of the cell A-56 in the upper left corner of the drawing. That is, the inlet 13 is provided on the opposite side of the row 2 of the single cells A-1 on one end side of the row 1, and the outlet 14 is provided on the opposite side of the row 1 of the single cells A-56 on the one end side of the row 2. This is called a battery pack.

  Then, the air enters the air passage 12 from the inlet 13 and flows on the right side (opposite side of the column 2) in the row 1 toward the other end along the row 1 (downward in the drawing). The air passage 12 is folded along the outer periphery at the lower end portion of the assembled battery 10. Therefore, the air flows from right to left in the drawing along the lower side of the cells A-28 and A-29 arranged at the other end in the drawing. Further, the left side of the column 2 in the figure (the opposite side of the column 1) flows toward the one end along the column 2 (upward in the figure) and is discharged from the outlet 14.

  Note that a slight gap is provided between the flat surfaces of each unit cell by means of, for example, sandwiching a comb-shaped holding member. A part of the air in the air passage 12 flows from the row 1 side to the row 2 side through the gap. That is, as shown by the dotted arrow Y in FIG. 1, the air flows from the right to the left in the figure through each cell.

  The inventor measured the temperature distribution generated in each unit cell in use in the assembled battery 10 in which the air flow indicated by arrows W and Y in FIG. 1 flows. That is, in the monitoring vehicle equipped with the assembled battery 10, a thermistor was installed in each of the unit cells A-1 to A-56, and the temperature of each unit cell during traveling was measured. The result is shown in FIG. That is, the unit cell (with a small battery number) close to the inlet of the air passage 12 was relatively low temperature. Further, the middle one was hotter than the last battery number near the outlet 14 of the air passage 12.

  In addition, the inventor investigated the high rate deterioration of the unit cell incorporated in the assembled battery 10. High-rate degradation is degradation that proceeds by using a battery under high-rate conditions. For example, as shown in the example of FIG. 3, a use condition in which rapid discharge or rapid charge is performed is a high rate condition. In particular, a rapid discharge has a heavy load on each single cell included in the assembled battery 10. For this reason, it is known that the deterioration progresses greatly when the use under high-rate conditions is repeated. The high rate condition is inevitably generated depending on the driving condition of the vehicle, and the occurrence itself cannot be prevented.

Therefore, the present inventor investigated the degree of progress of the deterioration of the unit cell in use under such a high rate condition as a relationship with the use temperature, the amount of electrolyte, and SOC. That is, the following three types of tests were performed.
(1) Difference in progress of high rate deterioration due to difference in use temperature (2) Relationship between amount of electrolyte stored in battery and progress of high rate deterioration (3) Target SOC for controlling battery and progress of high rate deterioration connection of

  The SOC value is a parameter indicating the state of charge of the battery. Within the range of reversibly chargeable / dischargeable battery voltage, the state of charge in which the upper limit battery voltage is obtained is said to be 100% SOC, and the state of charge in which the lower limit battery voltage is obtained is said to be 0% SOC. Therefore, a large value indicates that the battery is more charged, for example, close to full charge. In addition, the small value indicates that the battery is not charged so much and the state of charge is close to complete discharge, for example.

  In this experiment, as an evaluation condition, first, the target value of the SOC of the battery was set to 60%, and the following measurement cycle was used. A set of 150A10s discharge and 40A120sCCCV (Constant Current Constant Voltage) charge was set as one cycle, and the battery was repeated a predetermined number of cycles. That is, it was discharged at 150 A for 10 seconds, and then charged at a constant current of 40 A for 120 seconds. Thereby, the SOC of the battery is about 60% after charging. This charge / discharge condition corresponds to a high rate condition.

(1) Operating temperature and high-rate degradation A single cell is placed in three environments of 25 ° C, 40 ° C, and 60 ° C, and the resistance of the single cell increases at the above measurement cycles of 2000, 5000, and 9000 times. The rate was measured. The result of experiment (1) was as shown in FIG. The resistance increased greatly with the lower number of cycles in the low temperature environment. This increase in resistance is due to the deterioration of the cell. In other words, in these temperature ranges, it was found that the deterioration progressed more slowly as it was used in a higher temperature environment. In the low-temperature environment, the deterioration progressed quickly.

(2) Electrolyte Volume and High Rate Degradation Three types were prepared: a single battery with a +6 g or +9 g amount of electrolyte stored in a single battery, and a standard quantity. In general, in an assembled battery mounted on a vehicle, +6 g is about +10 to 13% of the standard amount, and +9 g is about +15 to 20% of the standard amount. In the cell used in this embodiment, +6 g corresponds to about + 10% of the standard amount, and +9 g corresponds to about + 15% of the standard amount. These single cells were subjected to the above measurement cycle, and the 150A10s resistance was measured at 400 cycles and 1000 cycles, respectively. That is, the resistance immediately after discharging at 150 A for 10 seconds at each cycle number was measured.

  The result of experiment (2) was as shown in FIG. That is, as the amount of the electrolyte increased, the resistance value increased significantly between 400 and 1000 times. This indicates that the deterioration has greatly progressed during that time. From this, it was found that the higher the electrolyte amount, the faster the high rate degradation progressed.

(3) SOC and high-rate deterioration The same type of single cells were controlled with different target SOCs, and the SOC target values were compared between 60% and 40%. In other words, in addition to the measurement conditions described above, measurement was performed on the measurement conditions in which the SOC target value was changed to 40%. In order to set the SOC to 40%, the charge / discharge cycle is basically the same as the previous measurement condition, but the charge time is shorter than the previous condition. And the measurement cycle similar to the above was implemented to 1000 cycles, measuring 150A10s resistance suitably with respect to these single cells.

  The result of experiment (3) was as shown in FIG. In other words, the increase in resistance with respect to the number of cycles was not so great with the SOC of 60%, whereas the resistance increased considerably with the number of cycles when the SOC was 40%. As a result, it was found that the deterioration progressed considerably faster with SOC 40% than with 60%.

  From the above three types of experiments, it has been found that in this embodiment, the progress of high-rate deterioration is particularly fast under the following three conditions. (1) The temperature environment is low, (2) the amount of electrolyte is large, and (3) the SOC is low. Under these reverse conditions, the progress of high rate degradation is slow.

  Therefore, based on the above experimental results, in this embodiment, the high-rate deterioration progress states of the individual cells A-1 to A-56 included in the assembled battery 10 are substantially the same. In the assembled battery 10 of this embodiment, as described above, the temperature environment during use is slightly different depending on the arrangement of the single cells. For this reason, if all the conditions other than the temperature environment are made equal, a difference occurs in the progress of the high rate deterioration due to the arrangement of the single cells. It is not preferable that the deterioration of only a part of the single cells is greatly deteriorated because a large voltage variation is caused inside the assembled battery 10. Therefore, by combining the other conditions (2) or (3), variations in high rate deterioration due to temperature are canceled. As a result, the progress of the high rate deterioration of each unit cell is combined.

  High-rate degradation due to temperature conditions is likely to progress in single cells that tend to be in a low-temperature environment during use, and are placed near the air inlet. For example, it is a single cell indicated by a range P in FIG. This range P is a single cell belonging to a section on one end side by dividing row 1 into two, as indicated by hatching in FIG. In the assembled battery 10 of this embodiment, the cells A-1 to A-12. Therefore, the cells A-1 to A-12 belonging to this range P and the other cells (cells A-13 to A-56) are divided, and the conditions other than the temperature are different depending on which of them belongs. Yes.

  That is, in the present embodiment, the condition of (2) or (3) is used so that the high rate deterioration of the cells in this range P is the same as that of the other cells. That is, the amount of the electrolyte is reduced in the range P unit cell as compared with other cells (first embodiment). Alternatively, the SOC of the single cell in the range P is set higher than that of other cells (second embodiment).

(First form)
In the assembled battery 10 of the first embodiment, the amount of the electrolytic solution of the single cell corresponding to the range P in FIG. That is, two types of single cells having different amounts of electrolyte contained therein are prepared, and a small one is placed in this range P and a large one is placed in another region. Since the single cells arranged in the range P are in a low temperature environment, the high rate deterioration proceeds faster than the others. On the other hand, high-rate deterioration progresses more slowly with a small amount of electrolyte than with a large amount of electrolyte. Therefore, by disposing a single battery with a small amount of electrolyte in the range P, it is possible to match the degree of progress of the high rate deterioration in the entire assembled battery 10.

  However, the standard liquid volume is the optimal liquid volume for the unit cell, and it is usually difficult to make the liquid volume smaller than this. For this reason, the liquid amount of the cells outside the range P is slightly increased from the standard liquid amount. Even if it does in this way, it will become more desirable from a viewpoint of deterioration of the whole assembled battery. It should be noted that the amount of the electrolytic solution may be further increased, and the smaller the amount of the electrolytic solution, the smaller the amount may be arranged at a low temperature environment position. Here, preparing may mean that a single cell that satisfies the condition is manufactured in-house. Alternatively, it may be manufactured by subcontracting and obtained, or if a product with the applicable conditions exists in the market, it may be purchased.

(Second form)
As shown in FIG. 8, the assembled battery module 20 according to the second embodiment includes the assembled battery 10 and control units 21 and 22 for controlling the assembled battery 10. Both of these control units 21 and 22 perform so-called equalization control. The equalization control is control for equalizing the state of charge of each unit cell incorporated in the assembled battery. This control can be performed, for example, by discharging a single cell whose voltage has become too high compared to other batteries, as described in Japanese Patent Application Laid-Open No. 2001-218376. The control units 21 and 22 of this embodiment perform equalization control with different SOCs as targets.

  In the assembled battery 10 of this embodiment, the control unit 21 controls the cells A-1 to A-12 included in the range P that is a low temperature environment. The control unit 22 controls the cells A-13 to A-56 other than the range P. And the control part 21 is controlled so that SOC becomes high compared with the control part 22. FIG. Thereby, it is possible to control a single cell, which tends to be in a low temperature environment, to have a higher SOC than other cells.

  As a result, the single cells A-1 to A-12 arranged in the range P have a high rate of deterioration due to a low temperature environment and a high SOC compared to the other cells. High rate degradation is slow. Therefore, it is possible to match the progress of the high rate deterioration in the entire assembled battery 10. Note that the control unit 21 may not be provided as long as the high SOC state can be maintained without performing the equalization control.

  In the first and second embodiments described above, the way of dividing the low-temperature cell into other cells is not limited to the range P shown in FIG. As shown in FIG. 2, various patterns are possible by setting the boundary temperature for classification. For example, the high temperature range Q shown in FIG. 2 may be set, and other ranges may be used as the low temperature environment range. In this case, as indicated by hatching in FIG. 9, the cell 2 is divided into two and the cells belonging to the section on the other end side are included in the range Q. In this example, the single cells A-29 to A-43 included in the range Q are set to a region where the temperature becomes high when used, and the other single cells A-1 to A-28 and A-44 to A-56 are set to a low temperature when used. It becomes an area to become.

  Alternatively, the low temperature region and the high temperature region may be divided so as to be in a range extending over the rows 1 and 2. In this case, for example, the number of single cells belonging to the low temperature region and the number of single cells belonging to the high temperature region can be classified so as to be approximately the same. For example, the division is as shown by the low temperature range R1 and the high temperature range R2 in FIG. In this case, as shown in FIG. 10, column 1 and column 2 are each divided into two. However, the portion that divides row 1 into two is closer to the other end side, and the portion that divides row 2 into two is closer to the one end side than the portion that divides row 1 into two. 10, that is, the cells A-1 to A-26, A-55 belonging to the range in which the section on one end side from the bisected portion is combined in each of the columns 1 and 2. A-56 is included in the low temperature range R1. The remaining single cells A-27 to A-54 are set to the high temperature range R2.

  Furthermore, it is not limited to the one that divides into a region where the temperature is low and a region where the temperature is high. Alternatively, this division method may be variable depending on the outside air temperature.

  This assembled battery 10 or battery pack is used by being mounted on a vehicle 200 as shown in FIG. 11, for example. The vehicle 200 is a hybrid vehicle that is driven by using an engine 240, a front motor 220, and a rear motor 230 in combination. The vehicle 200 includes a vehicle body 290, an engine 240, a front motor 220, a rear motor 230, a cable 250, an inverter 260, and a plurality of secondary batteries (unit cells) attached thereto. have.

  The vehicle may be a vehicle that uses battery-generated electric energy for all or a part of its power source. For example, an electric vehicle, a hybrid vehicle, a plug-in hybrid vehicle, a hybrid railway vehicle, a forklift, an electric vehicle Wheelchairs, electric assist bicycles, electric scooters, etc. are listed.

  Alternatively, the assembled battery 10 or the battery pack can be used for a battery-equipped device as shown in FIG. Shown in this figure is a hammer drill 300 equipped with the assembled battery 10 of this embodiment. The hammer drill 300 is a battery-equipped device having the assembled battery 10 or the battery pack and the main body 320. The assembled battery 10 or the battery pack is detachably accommodated in the bottom 321 of the main body 320 of the hammer drill 300.

  The battery-equipped device may be any device equipped with a battery and using it as at least one energy source. For example, a personal computer, a mobile phone, a battery-powered electric tool, an uninterruptible power supply, etc. Various types of home appliances, office equipment, and industrial equipment driven by The assembled battery 10 or the battery pack mounted on the vehicle 200 or the battery-equipped device may be of the first form or the second form.

  As described above in detail, according to the assembled battery 10 of the present embodiment, even if the temperature differs for each unit cell depending on the use environment, the degree of progress of the high rate deterioration can be adjusted. That is, since the high-rate deterioration tends to proceed when the usage environment is low, the degree of deterioration can be matched with other batteries by reducing the amount of the electrolyte or increasing the SOC. Therefore, it is possible to suppress the variation in the high rate deterioration of each unit cell included in the assembled battery 10.

In addition, this form is only a mere illustration and does not limit this invention at all. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof.
For example, although the above embodiment shows an example in which air is used as the cooling medium, the cooling medium is not limited to air. For example, it can be cooled by water cooling with water or oil cooling with oil. In this embodiment, all the cells are connected in series, but the form of electrical connection is not limited to this. For example, a plurality of single cells connected in series may be connected in parallel. Any battery can be used as long as it is an assembled battery whose operating temperature differs slightly depending on the unit cell. Further, the unit cell incorporated in the assembled battery is not limited to the lithium ion secondary battery.

DESCRIPTION OF SYMBOLS 10 Assembly battery 12 Air path 13 Inlet 14 Outlet 21,22 Control part 200 Vehicle 300 Hammer drill A-1 to A-56 Single cell

Claims (16)

In an assembled battery combining a plurality of secondary batteries,
Compared with the amount of electrolyte in the plurality of secondary batteries disposed in the region where the temperature is lower during use,
Among the plurality of secondary batteries, an assembled battery having a large amount of electrolyte in a battery disposed in a region that becomes hot when used. In the battery pack having the assembled battery according to claim 1,
An inlet for taking in a cooling medium for cooling the plurality of secondary batteries;
An outlet for discharging the cooling medium,
The region where the temperature becomes lower during use is a region including the battery closest to the entrance in the assembled battery,
The battery pack, wherein the region that becomes hotter during use is a region other than that in the assembled battery. The assembled battery according to claim 1,
The plurality of secondary batteries are arranged in two rows;
A cooling medium is taken in from the opposite side of the second row of secondary batteries at one end of the first row, and the opposite end of the second row of each secondary battery of the first row is directed from the one end to the other end. The cooling medium is then flown, folded at the other ends of the first row and the second row, and from the other end to the one end on the opposite side of the first row in each secondary battery of the second row. A cooling medium path is formed for flowing the cooling medium and discharging the cooling medium from the opposite side of the first row in the secondary battery at the one end of the second row;
The amount of the electrolyte solution of the secondary battery belonging to the one end side section when the first row is divided into the one end side section and the other end side section is small,
An assembled battery, wherein the secondary battery belonging to the other end of the first row and the secondary battery belonging to the second row have a large amount of electrolyte. The assembled battery according to claim 1,
The plurality of secondary batteries are arranged in two rows;
A cooling medium is taken in from the opposite side of the second row of secondary batteries at one end of the first row, and the opposite end of the second row of each secondary battery of the first row is directed from the one end to the other end. The cooling medium is then flown, folded at the other ends of the first row and the second row, and from the other end to the one end on the opposite side of the first row in each secondary battery of the second row. A cooling medium path is formed for flowing the cooling medium and discharging the cooling medium from the opposite side of the first row in the secondary battery at the one end of the second row;
When the second row is divided into the one end side section and the other end side section, the amount of the electrolyte solution of the secondary battery belonging to the other end side section is large,
The assembled battery, wherein the secondary battery belonging to the first row and the secondary battery belonging to the one end side of the second row have a small amount of electrolyte. The assembled battery according to claim 1,
The plurality of secondary batteries are arranged in two rows;
A cooling medium is taken in from the opposite side of the second row of secondary batteries at one end of the first row, and the opposite end of the second row of each secondary battery of the first row is directed from the one end to the other end. The cooling medium is then flown, folded at the other ends of the first row and the second row, and from the other end to the one end on the opposite side of the first row in each secondary battery of the second row. A cooling medium path is formed for flowing the cooling medium and discharging the cooling medium from the opposite side of the first row in the secondary battery at the one end of the second row;
The first row is divided into a section on the one end side and a section on the other end side, and the second row is arranged on the one end side at a location closer to the one end side than a bisected portion of the first row. And the second battery belonging to the one end side section of the first row and the second battery belonging to the one end side section of the second row. The amount of electrolyte in the secondary battery is small,
A battery pack comprising: a secondary battery belonging to a section on the other end side of the first row; and a secondary battery belonging to the other end side of the second row having a large amount of electrolyte. In a method for manufacturing an assembled battery in which a plurality of secondary batteries are combined,
Prepare secondary batteries with different amounts of electrolyte stored inside,
Place a secondary battery with a large amount of electrolyte in an area where the temperature is lower when in use.
A method for producing an assembled battery, characterized in that a secondary battery having a small amount of electrolyte is disposed in a region where the temperature is higher when in use. In an assembled battery module having an assembled battery in which a plurality of secondary batteries are combined and a charging state control unit that controls a charging state of each secondary battery of the assembled battery, the charging state control unit includes:
Compared to the state of charge in the plurality of secondary batteries that are arranged in a region where the temperature is lower during use,
An assembled battery module, wherein a state of charge of a plurality of secondary batteries disposed in a region that becomes hotter during use is lowered. The assembled battery module according to claim 7,
The assembled battery is a battery in which the plurality of secondary batteries are arranged in two rows,
A cooling medium is taken in from the opposite side of the second row of secondary batteries at one end of the first row, and the opposite end of the second row of each secondary battery of the first row is directed from the one end to the other end. The cooling medium is then flown, folded at the other ends of the first row and the second row, and from the other end to the one end on the opposite side of the first row in each secondary battery of the second row. A cooling medium path is formed for flowing the cooling medium and discharging the cooling medium from the opposite side of the first row in the secondary battery at the one end of the second row;
The charge state of the secondary battery belonging to the section on the one end side when the first row is divided into the section on the one end side and the section on the other end side is increased,
The assembled battery module, wherein the state of charge of the secondary battery belonging to the other end of the first row and the secondary battery belonging to the second row is lowered. The assembled battery module according to claim 7,
The assembled battery is a battery in which the plurality of secondary batteries are arranged in two rows,
A cooling medium is taken in from the opposite side of the second row of secondary batteries at one end of the first row, and the opposite end of the second row of each secondary battery of the first row is directed from the one end to the other end. The cooling medium is then flown, folded at the other ends of the first row and the second row, and from the other end to the one end on the opposite side of the first row in each secondary battery of the second row. A cooling medium path is formed for flowing the cooling medium and discharging the cooling medium from the opposite side of the first row in the secondary battery at the one end of the second row;
The charge state of the secondary battery belonging to the section on the other end when the second row is divided into the section on the one end side and the section on the other end side is low,
A battery pack module comprising: a secondary battery belonging to the first row; and a secondary battery belonging to the one end side of the second row being charged. The assembled battery module according to claim 7,
The assembled battery is a battery in which the plurality of secondary batteries are arranged in two rows,
A cooling medium is taken in from the opposite side of the second row of secondary batteries at one end of the first row, and the opposite end of the second row of each secondary battery of the first row is directed from the one end to the other end. The cooling medium is then flown, folded at the other ends of the first row and the second row, and from the other end to the one end on the opposite side of the first row in each secondary battery of the second row. A cooling medium path is formed for flowing the cooling medium and discharging the cooling medium from the opposite side of the first row in the secondary battery at the one end of the second row;
The first row is divided into a section on the one end side and a section on the other end side, and the second row is arranged on the one end side at a location closer to the one end side than a bisected portion of the first row. And the second battery belonging to the one end side section of the first row and the second battery belonging to the one end side section of the second row. The secondary battery has a low charge
The assembled battery module, wherein the state of charge of the secondary battery belonging to the section on the other end side of the first row and the secondary battery belonging to the other end side of the second row is increased. The assembled battery module according to any one of claims 7 to 10,
The charge state control unit performs control to equalize the voltage of each secondary battery by discharging a secondary battery having a high charge state,
A secondary battery included in a region that becomes colder during use is not discharged or discharged only to a higher state of charge than a secondary battery included in a region that becomes hotter during use. Battery module. The assembled battery module according to claim 7,
The assembled battery is
An inlet for taking in a cooling medium for cooling the plurality of secondary batteries;
A battery pack having an outlet for discharging the cooling medium;
The region where the temperature becomes lower during use is a region including the battery closest to the entrance in the assembled battery,
The assembled battery module, wherein the region that becomes hotter during use is a region other than that in the assembled battery. A vehicle comprising the assembled battery or the battery pack according to any one of claims 1 to 5. A vehicle comprising the assembled battery module according to any one of claims 7 to 12. A battery-equipped device comprising the assembled battery or the battery pack according to any one of claims 1 to 5. A battery-mounted device comprising the assembled battery module according to any one of claims 7 to 12.

Images