JP6948567B2 - Battery abnormality detection system - Google Patents

Description

The present invention relates to a battery abnormality detection system.

A battery such as a lithium ion secondary battery is generally used as a battery stack including a plurality of batteries or a battery pack in which a plurality of the battery stacks are combined. Here, if the temperature of each battery varies in the same stack, the battery performance may vary between the batteries. If the battery performance varies, the possibility of overcharging in each battery increases. Here, as a technique for detecting a temperature change of a battery, for example, Patent Document 1 discloses a technique for utilizing cooling air flowing toward the battery during high-load traveling. Further, Patent Document 2 and Patent Document 3 are mentioned as control techniques based on the temperature of the battery.

Japanese Unexamined Patent Publication No. 2015-129677 Japanese Unexamined Patent Publication No. 2016-167420 Japanese Unexamined Patent Publication No. 2012-029491

By the way, in the technique described in Patent Document 1, the cooling air flows only during high-load traveling and does not flow during normal traveling. In addition, the cooling air does not flow even during parking, which is the most frequently used form in the market, and changes in battery temperature cannot be detected. That is, it is not possible to detect an abnormality in a battery pack having a plurality of batteries while parking.

The present invention has been made in view of such a point, and an object of the present invention is to provide a battery abnormality detection system capable of detecting an abnormality of a battery pack while parking.

The battery abnormality detection system according to the present invention is a battery abnormality detection system mounted on a vehicle including a battery pack having a plurality of vehicle drive batteries and a storage case for accommodating the plurality of vehicle drive batteries. The battery abnormality detection system measures the temperature TB of the plurality of vehicle driving batteries at the end of traveling and the temperature TBx of the plurality of vehicle driving batteries when a predetermined time has elapsed from the end of traveling. A detection device, a second temperature detection device that measures the atmospheric temperature TA in the storage case at the end of traveling, and a third that measures the outside air temperature TO of the vehicle when the predetermined time elapses from the end of traveling. It includes a temperature detection device and a control device. The control device includes a first estimation formula for obtaining an estimated atmospheric temperature TAy in the accommodation case when the predetermined time elapses from the end of traveling, and when the predetermined time elapses from the end of traveling. In the storage case, based on the storage unit for storing the second estimation formula for obtaining the estimated temperature TBy of each vehicle driving battery, the first estimation formula, the atmosphere temperature TA, and the outside temperature TO. The first calculation unit that calculates the estimated atmosphere temperature TAy, and the second calculation unit that calculates the estimated temperature TBy of each vehicle drive battery based on the second estimation formula, the estimated atmosphere temperature TAy, and the temperature TB. A third calculation unit that calculates ΔTBy, which is the difference between the maximum estimated temperature TBy (max) and the minimum estimated temperature TBy (min), among the estimated temperature TBy of the plurality of vehicle driving batteries, and the plurality of the above. Of the temperature TBx of the vehicle driving battery, the fourth calculation unit that calculates ΔTBx, which is the difference between the maximum measured temperature TBx (max) and the minimum measured temperature TBx (min), and when the ΔTBx is larger than the ΔTBy. Is determined to be abnormal, and when the ΔTBx is equal to or less than the ΔTBy, it is determined to be normal, and when the determination unit determines that the temperature is abnormal, the estimated temperature TBy and the temperature TBx are compared and the abnormality is found. It has a judgment unit to judge the type.

According to the battery abnormality detection system according to the present invention, the abnormality of the battery pack is determined by comparing ΔTBy calculated from the estimated estimated temperature TBy with ΔTBx calculated from the actually measured temperature TBx. be able to. That is, the determination unit determines that it is abnormal when ΔTBx is larger than ΔTBy, and determines that it is normal when ΔTBx is less than or equal to ΔTBy. In this way, even when the vehicle is parked, it is possible to accurately detect whether or not an abnormality has occurred in the battery pack. In addition, since it is possible to detect the presence or absence of an abnormality in the battery pack when the vehicle driving battery is not used, it is more excellent in safety. Further, the determination unit determines the type of abnormality of the battery pack by comparing the estimated temperature TBy and the temperature TBx. This makes it possible to identify the cause of the abnormality.

It is a top view which shows typically the battery abnormality detection system mounted on a vehicle. It is a flowchart which shows the procedure for confirming the state of the battery pack after parking. It is a graph which shows the temperature change after parking of a vehicle driving battery in a normal state. It is a graph which shows the temperature change after parking of a vehicle driving battery in an abnormal state.

Hereinafter, preferred embodiments of the present invention will be described. Matters other than those specifically mentioned in the present specification and necessary for carrying out the present invention can be grasped as design matters of those skilled in the art based on the prior art in the art. The present invention can be carried out based on the contents disclosed in the present specification and common general technical knowledge in the art. It should be noted that each drawing is drawn schematically and does not necessarily reflect the actual product. In addition, each drawing shows only one example, and each drawing does not limit the present invention unless otherwise specified. Further, the symbols F, Rr, L, and R in the drawing mean front, back, left, and right, respectively. However, these are directions for convenience of explanation, and do not limit the installation mode of the battery abnormality detection system at all.

As shown in FIG. 1, the vehicle 10 includes a battery pack 20 and a battery abnormality detection system 30. In the present embodiment, the battery pack 20 is arranged under the rear seat of the vehicle 10 and fixed to the floor panel. However, the battery pack 20 may be arranged on a position other than the lower side of the rear seat.

The battery pack 20 includes a battery stack 22, a storage case 23, and a filter 24. The battery stack 22 includes four vehicle driving batteries 21. Each of the four vehicle driving batteries 21 has a square outer shape, and is arranged in a row in the left-right direction of FIG. 1 so that a pair of flat surfaces face each other. The four vehicle drive batteries 21 are electrically connected to each other in series by a bus bar. The four vehicle drive batteries 21 are integrally held by a restraint band or the like. However, the shape, number, arrangement, etc. of the vehicle drive battery 21 may be changed as appropriate. The vehicle drive battery 21 is typically a rechargeable / dischargeable secondary battery, such as a lithium ion secondary battery. The vehicle drive battery 21 typically includes a positive electrode, a negative electrode, an electrolytic solution, and a cell cell case for accommodating them. The electrolytic solution contains, for example, a non-aqueous solvent such as carbonates and a supporting salt such as a lithium salt. The configuration of the cell is the same as the conventional one, and is not particularly limited.

The storage case 23 is a housing for storing the battery stack 22. The material of the storage case 23 is, for example, metal or resin. The shape and size of the storage case 23 may be appropriately changed according to, for example, the size and number of battery stacks 22. The filter 24 is detachably provided in the storage case 23. The inside of the storage case 23 and the outside of the storage case 23 communicate with each other via a filter 24. The filter 24 prevents dust from entering the storage case 23.

As shown in FIG. 1, the battery abnormality detection system 30 includes a first temperature detection device 31, a second temperature detection device 32, a third temperature detection device 33, and a control device 35.

The first temperature detection device 31 is a device that measures the temperature of the vehicle drive battery 21. Examples of the first temperature detection device 31 include a thermocouple. The first temperature detection device 31 is provided in each vehicle driving battery 21. The first temperature detecting device 31 is attached to, for example, the cell cell case of the vehicle driving battery 21. The first temperature detection device 31 is electrically connected to the control device 35. The temperature information measured by the first temperature detection device 31 is transmitted to the control device 35.

The first temperature detection device 31 measures the temperature TB of each vehicle drive battery 21 at the end of traveling. The first temperature detection device 31 measures the temperature TBx of each vehicle driving battery 21 when a predetermined time t has elapsed from the end of traveling (that is, when a predetermined time t has elapsed after parking). The predetermined time t can be arbitrarily set, for example, 10 minutes, 30 minutes, 1 hour, or the like.

The second temperature detection device 32 is a device that measures the ambient temperature inside the storage case 23. The second temperature detection device 32 measures the atmospheric temperature TA in the accommodation case 23 at the end of traveling. Examples of the second temperature detection device 32 include a thermocouple. The second temperature detection device 32 is arranged in the storage case 23. The second temperature detection device 32 is electrically connected to the control device 35. The temperature information measured by the second temperature detection device 32 is transmitted to the control device 35.

The third temperature detection device 33 is a device that measures the outside air temperature of the vehicle 10. The third temperature detection device 33 measures the outside air temperature TO of the vehicle 10 when a predetermined time t has elapsed from the end of traveling, that is, when a predetermined time t has elapsed after parking. Examples of the third temperature detection device 33 include a thermistor. The third temperature detection device 33 is provided, for example, on the back side of the front bumper of the vehicle 10. The third temperature detection device 33 is electrically connected to the control device 35. The temperature information measured by the third temperature detection device 33 is transmitted to the control device 35.

The control device 35 includes a central processing unit (CPU) that executes instructions of a control program, a ROM that stores a program executed by the CPU, a RAM that is used as a working area for developing the program, and the above program and various data. It is equipped with a storage device such as a memory for storing the data. The control device 35 includes a storage unit 37, a first calculation unit 39, a second calculation unit 41, a third calculation unit 43, a fourth calculation unit 45, a determination unit 47, a determination unit 49, and a notification unit. It is equipped with 51. Each of these parts is realized by a program. This program can be downloaded via the internet. Further, each of these parts may be feasible by a processor and / or a circuit or the like. The specific control of each part described above will be described later.

The storage unit 37 stores the first estimation formula and the second estimation formula. The first estimation formula is a formula for obtaining the estimated atmosphere temperature TAy in the accommodation case 23 when a predetermined time t has elapsed from the end of traveling, and is expressed by the following formula (1). In equation (1), β is a constant obtained by a preliminary experiment. The second estimation formula is a formula for obtaining the estimated temperature TBy of each vehicle driving battery 21 when a predetermined time t has elapsed from the end of traveling, and is expressed by the following formula (2). In equation (2), α is a constant obtained by a preliminary experiment. C is the heat capacity of the vehicle drive battery 21. t is a predetermined time elapsed from the end of traveling.

The first calculation unit 39 is based on the first estimation formula stored in the storage unit 37, the atmospheric temperature TA measured by the second temperature detection device 32, and the outside air temperature TO measured by the third temperature detection device 33. The estimated atmospheric temperature TAy in the storage case 23 is calculated.

The second calculation unit 41 is based on the second estimation formula stored in the storage unit 37, the estimated atmosphere temperature TAy calculated by the first calculation unit 39, and the temperature TB measured by the first temperature detection device 31. The estimated temperature TBy of the vehicle driving battery 21 is calculated.

The third calculation unit 43 is the difference between the maximum estimated temperature TBy (max) and the minimum estimated temperature TBy (min) among the estimated temperature TBy of the plurality of vehicle driving batteries 21 calculated by the second calculation unit 41. Calculate a certain ΔTBy. For example, the estimated temperature TBy of the first vehicle driving battery 21 is X1 ° C., the estimated temperature TBy of the second vehicle driving battery 21 is X2 ° C., the estimated temperature TBy of the third vehicle driving battery 21 is X3 ° C., When the estimated temperature TBy of the fourth vehicle driving battery 21 is X4 ° C. (X1> X2> X3> X4), X1 ° C. corresponds to the maximum estimated temperature TBy (max) and X4 ° C. is the minimum estimated temperature TBy (min). ) Corresponds.

The fourth calculation unit 45 sets the maximum measured temperature TBx (max) and the minimum measured temperature TBx (min) among the respective temperatures TBx of the plurality of vehicle driving batteries 21 actually measured by the first temperature detecting device 31. Calculate the difference ΔTBx. For example, the temperature TBx of the first vehicle drive battery 21 is Y1 ° C., the temperature TBx of the second vehicle drive battery 21 is Y2 ° C., the temperature TBx of the third vehicle drive battery 21 is Y3 ° C., and the fourth. When the temperature TBx of the vehicle drive battery 21 is Y4 ° C. (Y1> Y2> Y3> Y4), Y1 ° C. corresponds to the maximum measured temperature TBx (max) and Y4 ° C. corresponds to the minimum measured temperature TBx (min). ..

When the ΔTBx calculated by the fourth calculation unit 45 is larger than the ΔTBy calculated by the third calculation unit 43, the determination unit 47 determines that it is abnormal. That is, the determination unit 47 determines that an abnormality has occurred in the battery pack 20. The determination unit 47 determines that it is normal when ΔTBx is ΔTBy or less. That is, the determination unit 47 determines that the battery pack 20 is normal.

When the determination unit 47 determines that the abnormality is present, the determination unit 49 compares the estimated temperature TBy with the temperature TBx to determine the type of abnormality. That is, the determination unit 49 compares the estimated temperature TBy and the temperature TBx of each vehicle driving battery 21 and determines whether or not there is a vehicle driving battery 21 in which the estimated temperature TBy and the temperature TBx are substantially equal.

When there is a vehicle drive battery 21 in which the estimated temperature TBy and the temperature TBx are substantially equal, dust is accumulated on the vehicle drive battery 21 in which the estimated temperature TBy and the temperature TBx are not substantially equal. It can be confirmed that the heat is not sufficiently dissipated. That is, in the normal vehicle driving battery 21, the estimated temperature TBy and the temperature TBx are substantially equal because heat can be sufficiently dissipated.

When there is no vehicle driving battery 21 in which the estimated temperature TBy and the temperature TBx are substantially the same, it can be confirmed that the filter 24 provided in the accommodation case 23 is clogged. That is, due to the clogging of the filter 24, heat is trapped in the housing case 23, and the temperature of the plurality of vehicle driving batteries 21 as a whole is high.

The notification unit 51 notifies the user of the abnormality of the battery pack 20. The notification unit 51 notifies that the heat dissipation is insufficient due to the accumulation of dust on any of the vehicle driving batteries 21, or that the filter 24 is clogged. The notification method is not particularly limited, and examples thereof include visual display, voice notification, and the like. In the present embodiment, the operator is visually notified through a display panel (not shown) provided on the vehicle 10.

Next, a method of checking the state of the battery pack 20 after parking will be described. FIG. 2 is a flowchart according to an embodiment. At the time of shipment of the vehicle 10, the first estimation formula (1) and the second estimation formula (2) are stored in the storage unit 37. When the vehicle 10 is parked, the vehicle driving battery 21 is not charged or discharged.

First, when the traveling of the vehicle 10 is completed (that is, when the vehicle 10 is parked), in step S10, the first temperature detection device 31 measures the temperature TB of the vehicle driving battery 21 at the end of traveling. Further, the second temperature detection device 32 measures the atmospheric temperature TA in the accommodation case 23 at the end of traveling.

Next, when the predetermined time t elapses, in step S20, the third temperature detection device 33 measures the outside air temperature TO of the vehicle 10.

In step S30, the first calculation unit 39 is based on the first estimation formula (1) stored in the storage unit 37, the atmospheric temperature TA measured in step S10, and the outside air temperature TO measured in step S20. The estimated atmospheric temperature TAy in the storage case 23 is calculated.

In step S40, the second calculation unit 41 is based on the second estimation formula (2) stored in the storage unit 37, the estimated atmosphere temperature TAy calculated in step S30, and the temperature TB measured in step S10. The estimated temperature TBy of each vehicle driving battery 21 is calculated.

In step S50, the third calculation unit 43 calculates ΔTBy, which is the difference between the maximum estimated temperature TBy (max) and the minimum estimated temperature TBy (min) among the estimated temperature TBy calculated in step S40.

In step S60, the first temperature detecting device 31 measures the temperature TBx of each vehicle driving battery 21 when a predetermined time t has elapsed from the end of traveling.

In step S70, the fourth calculation unit 45 calculates ΔTBx, which is the difference between the maximum measured temperature TBx (max) and the minimum measured temperature TBx (min) among the respective temperature TBx calculated in step S60.

In step S80, the determination unit 47 determines whether or not ΔTBx calculated in step S70 is larger than ΔTBy calculated in step S50. If it is determined that ΔTBx is larger than ΔTBy, the process proceeds to step S90. On the other hand, when it is determined that ΔTBx is ΔTBy or less, the battery pack 20 is in a normal state, and the process ends.

In step S90, the determination unit 49 determines whether or not there is a vehicle drive battery 21 having an estimated temperature TBy equal to the temperature TBx among the plurality of vehicle drive batteries 21. If there is a vehicle drive battery 21 having an estimated temperature TBy equal to the temperature TBx, the process proceeds to step S100. On the other hand, if there is no vehicle driving battery 21 having an estimated temperature TBy equal to the temperature TBx, the process proceeds to step S110.

In step S100, the notification unit 51 notifies the user that dust is accumulated in a part of the plurality of vehicle driving batteries 21, and ends the process. As a result, the user can recognize that the inside of the battery pack 20 needs to be cleaned.

In step S110, the notification unit 51 notifies the user that the filter 24 is clogged, and ends the process. This allows the user to recognize that the filter 24 needs to be cleaned or replaced.

3 and 4 are graphs showing the temperature change of the vehicle driving battery 21 for 1 hour after parking. The broken lines in FIGS. 3 and 4 indicate the temperature change of the maximum estimated temperature TBy (max). The alternate long and short dash line in FIGS. 3 and 4 shows the temperature change of the maximum measured temperature TBx (max). The solid lines in FIGS. 3 and 4 show the temperature change of the minimum estimated temperature TBy (min). The alternate long and short dash line in FIGS. 3 and 4 shows the temperature change of the minimum measured temperature TBx (min). As shown in FIG. 3, when ΔTBx is ΔTBy or less, the determination unit 47 determines that the battery pack 20 is in a normal state. On the other hand, as shown in FIG. 4, when ΔTBx is larger than ΔTBy, the determination unit 47 determines that an abnormality has occurred in the battery pack 20. In the present embodiment, since ΔTBy is set in consideration of the environmental state, the state of the battery pack 20 can be detected more accurately than in the case where ΔTBy is set uniformly as in the conventional case.

As described above, according to the battery abnormality detection system 30 according to the present embodiment, by comparing ΔTBy calculated from the estimated estimated temperature TBy with ΔTBx calculated from the actually measured temperature TBx, It is possible to determine the abnormality of the battery pack 20. That is, the determination unit 47 determines that an abnormality has occurred in the battery pack 20 when ΔTBx is larger than ΔTBy, and determines that the battery pack 20 is in a normal state when ΔTBx is ΔTBy or less. In this way, even when the vehicle 10 is parked, it is possible to accurately detect whether or not an abnormality has occurred in the battery pack 20. Further, since it is possible to detect the presence or absence of an abnormality in the battery pack 20 when the vehicle driving battery 21 is not used, it is more excellent in safety. Further, the determination unit 49 determines the type of abnormality in the battery pack 20 by comparing the estimated temperature TBy and the temperature TBx. This makes it possible to identify the cause of the abnormality.

Although various battery abnormality detection systems proposed here have been described above, the embodiments and examples given here do not limit the present invention unless otherwise specified.

For example, in the above flowchart, the processes of steps S60 to S70 are performed after steps S20 to S50, but steps S60 to S70 may be processed before steps S20 to S50.

10 Vehicle 20 Battery pack 21 Vehicle drive battery 23 Storage case 24 Filter 30 Battery abnormality detection system 31 First temperature detection device 32 Second temperature detection device 33 Third temperature detection device 35 Control device 39 First calculation unit 41 Second calculation Unit 43 3rd calculation unit 45 4th calculation unit 47 Judgment unit 49 Judgment unit

Claims (1)

A battery abnormality detection system mounted on a vehicle including a battery pack having a plurality of vehicle drive batteries and a storage case for accommodating the plurality of vehicle drive batteries.
A first temperature detection device that measures the temperature TB of the plurality of vehicle drive batteries at the end of traveling and the temperature TBx of the plurality of vehicle drive batteries when a predetermined time has elapsed from the end of travel.
A second temperature detection device that measures the atmospheric temperature TA in the storage case at the end of traveling, and
A third temperature detection device that measures the outside air temperature TO of the vehicle when the predetermined time has elapsed from the end of traveling, and
Equipped with a control device,
The control device is
The first estimation formula for obtaining the estimated atmospheric temperature TAy in the accommodation case when the predetermined time elapses from the end of traveling, and the driving of each vehicle when the predetermined time elapses from the end of traveling. A storage unit that stores a second estimation formula for obtaining the estimated temperature TBy of the battery, and
A first calculation unit that calculates the estimated atmospheric temperature TAy in the storage case based on the first estimation formula, the atmospheric temperature TA, and the outside air temperature TO.
A second calculation unit that calculates the estimated temperature TBy of each vehicle drive battery based on the second estimation formula, the estimated atmosphere temperature TAy, and the temperature TB.
A third calculation unit that calculates ΔTBy, which is the difference between the maximum estimated temperature TBy (max) and the minimum estimated temperature TBy (min), among the estimated temperature TBy of the plurality of vehicle driving batteries.
A fourth calculation unit that calculates ΔTBx, which is the difference between the maximum measured temperature TBx (max) and the minimum measured temperature TBx (min), among the temperature TBx of the plurality of vehicle driving batteries.
When the ΔTBx is larger than the ΔTBy, it is determined to be abnormal, and when the ΔTBx is equal to or less than the ΔTBy, it is determined to be normal.
A battery abnormality detection system including a determination unit that determines the type of abnormality by comparing the estimated temperature TBy with the temperature TBx when the determination unit determines that the abnormality is abnormal.

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