JP6011865B2 - Secondary battery short circuit inspection method - Google Patents

Description

  The present invention relates to a secondary battery short circuit inspection method for inspecting a short circuit of a secondary battery mounted on a vehicle.

  Conventionally, in secondary battery manufacturing processes, etc., the presence or absence of short-circuits (micro short-circuits) that cause an increase in the voltage drop of the secondary battery and a decrease in thermal stability and charge / discharge characteristics has been inspected. (For example, refer to Patent Document 1).

In the secondary battery inspection method disclosed in Patent Document 1, after charging the secondary battery to a first SOC (State Of Charge, for example, a state close to 100%), the secondary battery is kept in a constant temperature room for a certain period of time. Leave (for example, about 12 days). And in the secondary battery test | inspection method disclosed by patent document 1, a secondary battery is discharged and it falls to 2nd SOC (for example, about 0% state).
Thereafter, in the secondary battery inspection method disclosed in Patent Document 1, the temperature of the secondary battery is lowered to a temperature low enough to reduce the voltage drop due to self-discharge, and the secondary battery is kept for a certain period (for example, about Leave for 8 days. In the secondary battery inspection method disclosed in Patent Document 1, the voltage value of the secondary battery at the time of being left is measured to detect a voltage drop degree, and a micro short circuit is determined based on the voltage drop degree.

JP 2011-69775 A

  A secondary battery may be short-circuited after shipment due to, for example, an external impact or an internal chemical reaction during use.

  The secondary battery inspection method disclosed in Patent Document 1 assumes that the secondary battery is inspected for short circuit before shipping, such as measuring the voltage value when the secondary battery is left in a constant temperature room for a certain period of time. It is.

  A secondary battery mounted on a vehicle such as an automobile after shipment is connected in series (or connected in parallel) with a plurality of secondary batteries to form a battery pack. In such a battery pack, generally, the voltages of a plurality of secondary batteries are aligned, and more specifically, the voltage of one secondary battery having a low voltage is matched with the voltage of another secondary battery. An equalization circuit is provided.

  Therefore, as shown in FIG. 14, when a micro short circuit is determined based on the voltage drop degree, the voltage is aligned by the equalization circuit, and as a result, the voltage drop degree of the secondary battery may not be accurately calculated. (See the arrow shown in FIG. 14B).

  That is, in the secondary battery inspection method disclosed in Patent Document 1, a facility for acquiring information necessary for the inspection is required, or an equalization circuit is present, so that the vehicle can be inspected after shipment. It was difficult to accurately detect a short circuit of the mounted secondary battery.

  The present invention has been made in view of the above situation, and provides a secondary battery short-circuit inspection method capable of accurately detecting a short-circuit of a secondary battery mounted on a vehicle.

  A secondary battery short-circuit inspection method according to the present invention is a secondary battery short-circuit inspection method for inspecting a short-circuit of a secondary battery mounted on a vehicle, wherein the secondary battery in a single run of the vehicle. An average discharge current value, a cumulative discharge current value, a discharge time, and a travel distance of the vehicle, a step of calculating a determination index by dividing the cumulative discharge current value by the discharge time, and a past Creating a reference matrix that stores the determination index calculated in the inspection as past accumulated data according to the average discharge current value and the travel distance, and calculating a determination value in advance for each past accumulated data of the reference matrix And, based on a result of comparing the determination index calculated in the current inspection with the average discharge current value acquired in the current inspection and the determination value corresponding to the travel distance, Performing a step of determining short-circuiting of the next cell, and is intended.

  In the secondary battery short-circuit inspection method according to the present invention, the determination index calculated in the current inspection is added to the past accumulated data of the reference matrix corresponding to the average discharge current value and the travel distance acquired in the current inspection. An adding step; a step of calculating an average value of the past accumulated data including a judgment index calculated in the current examination; a calculation result of the average value of the past accumulated data; the average discharge current value; and the travel distance And a step of updating the determination value corresponding to the average discharge current value and the mileage acquired in the current inspection by adding a coefficient set in advance according to the above.

  The present invention has an effect that a short circuit of a secondary battery mounted on a vehicle can be accurately detected.

Explanatory drawing which shows the structure of a short circuit inspection apparatus. Explanatory drawing which shows the matrix produced previously by the short circuit inspection method. (A) The figure which shows a reference | standard matrix. (B) The figure which shows the judgment value matrix. (C) The figure which shows a coefficient matrix. The figure which shows the procedure of a short circuit inspection method. Explanatory drawing which shows a mode that the past accumulation data are frequency-distributed when the secondary battery is not short-circuited. Explanatory drawing which shows a mode that it is confirmed to which grade the judgment index was counted. Explanatory drawing which shows a mode that the average value of frequency distribution is calculated. Explanatory drawing which shows a mode that a judgment value is recalculated. Explanatory drawing which shows a mode that a determination value is updated. Explanatory drawing which shows a mode that past accumulation data are frequency-distributed when a secondary battery short-circuits. Explanatory drawing which shows the state by which the judgment index was counted twice high continuously. Explanatory drawing which shows the state by which the judgment index was counted by the high grade 3 times continuously. Explanatory drawing which shows a mode that a judgment parameter | index and a judgment value are compared. The figure which shows frequency distribution of the result of dividing the cumulative discharge current value by the discharge time. (A) The figure which shows frequency distribution before a secondary battery short-circuits. (B) The figure which shows frequency distribution after a secondary battery short-circuits. Explanatory drawing which shows the relationship between time and a voltage value when a secondary battery short-circuits. (A) The figure when the equalization circuit does not operate | move. (B) The figure when the equalization circuit operates.

  Hereinafter, a short circuit inspection method for secondary batteries (hereinafter simply referred to as “short circuit inspection method”) will be described.

  In the present embodiment, the secondary battery 21 for inspecting a short circuit is a lithium ion secondary battery, but is not limited thereto. That is, the secondary battery 21 to be inspected by the short-circuit inspection method may be another secondary battery such as a nickel hydride secondary battery.

  As shown in FIG. 1, the short circuit inspection method of this embodiment is for inspecting a short circuit of a secondary battery 21 configured as a battery pack 20.

The battery pack 20 is configured by stacking a plurality of secondary batteries 21 with a separator interposed therebetween, fastening a bus bar or the like to an external terminal of each secondary battery 21, and connecting the secondary batteries 21 in series. . The battery pack 20 is mounted on the vehicle and supplies power to the generator of the vehicle.
Each secondary battery 21 has a rectangular shape in which an electrode body configured by laminating a positive electrode, a negative electrode, and a separator is wound in a battery container, and the battery container is sealed after injecting an electrolytic solution. It is a sealed battery.

  In addition, although the secondary battery 21 of this embodiment is comprised in the square battery in which the battery container was formed in the bottomed square tube shape, it is not restricted to this, For example, a battery container is bottomed. It may be a cylindrical battery formed in a cylindrical shape.

  The frequency distribution shown in FIG. 13 is a distribution of the result of dividing the cumulative discharge current value B of the battery pack 20 in one run by the discharge time C when the vehicle is run with a fixed usage. Each of the grades T1 to T5 is configured by dividing the size of the division result into a certain range, and the grade becomes a larger value from the grade T1 toward the grade T5.

  Here, in the present embodiment, the usage refers to, for example, a short-distance travel using only the electric power of the battery pack 20, or a long-distance travel using the battery pack 20 and fuel such as gasoline in combination. This indicates how the battery pack 20 is used and how much distance the vehicle has traveled.

When the vehicle is driven in a fixed (fixed) usage, the battery pack 20 is used in the same state. For this reason, when each secondary battery 21 is not short-circuited, the accumulated discharge current value B when the vehicle is driven in a fixed manner becomes a close value. The same applies to the discharge time C.
Therefore, as shown in FIG. 13A, when each secondary battery 21 is not short-circuited, one peak is formed in the intermediate grades T2 to T4 in the frequency distribution.

Each secondary battery 21 of the battery pack 20 may be short-circuited (micro-short-circuited) when metal scraps mixed inside due to an impact from the outside penetrate the separator accommodated in the battery container.
In addition, each secondary battery 21 may be short-circuited due to crystals deposited on the electrode layer due to an internal chemical reaction during use, and the short-circuit may gradually progress with time.
That is, each secondary battery 21 may be short-circuited after shipment.

Each secondary battery 21 short-circuited consumes battery energy by discharging.
Therefore, when the secondary battery 21 is short-circuited, the cumulative discharge current value B becomes larger than that before the short-circuit. In particular, when the secondary battery 21 is short-circuited due to an external impact, the cumulative discharge current value B becomes larger.

  When the short circuit of the secondary battery 21 proceeds due to internal chemical reaction during use, the value obtained by dividing the cumulative discharge current value B by the discharge time C (that is, the amount of current per unit time) is compared with that before the short circuit. May become large.

Therefore, the result obtained by dividing the accumulated discharge current value B acquired after the secondary battery 21 is short-circuited by the discharge time C is a value that is large enough to exceed the maximum value of the division result assumed before the short-circuit.
That is, as shown in FIG. 13B, the frequency distribution is obtained by dividing the cumulative discharge current value B by the discharge time C when the vehicle travels in a fixed manner (the secondary battery 21 is used in the same state). In this case, after the secondary battery 21 is short-circuited, a second peak is formed in the frequency distribution (see the right peak shown in FIG. 13B).

In addition, since the frequency distribution shown in FIG. 13 is each graded by a quintic, the range of each grade T1-T5 becomes wide after a short circuit.
For this reason, the count numbers of the respective grades T1 to T5 of the frequency distribution shown in FIG. 13A are collected in the grades T1 to T3 shown in FIG.

  The short circuit inspection method of this embodiment calculates the result obtained by dividing the cumulative discharge current value B in one run by the discharge time C as a determination index F, and confirms the second peak formed after the short circuit. The presence or absence of a short circuit of the secondary battery 21 mounted on the vehicle is inspected.

Next, in this embodiment, the short circuit inspection apparatus 10 used in order to perform the short circuit inspection method is demonstrated.
As shown in FIG. 1, the short circuit inspection apparatus 10 is mounted on a vehicle and includes a battery information acquisition unit 11, a vehicle information acquisition unit 12, a storage unit 13, an output unit 14, a calculation unit 15, and the like.

  The battery information acquisition unit 11 is for acquiring the average discharge current value A, the cumulative discharge current value B, and the discharge time C of each secondary battery 21 in one run. The battery information acquisition unit 11 is configured by, for example, an ammeter that measures the current value of the battery pack 20, and based on the current value measured by the ammeter, the average discharge current value A, the cumulative discharge current value B, and The discharge time C is calculated.

  The vehicle information acquisition unit 12 is for acquiring a travel distance D and a travel time E in one travel. The vehicle information acquisition unit 12 is electrically connected to, for example, an ECU (Engine Control Unit) that controls an engine of the vehicle, and acquires a travel distance D and a travel time E by receiving a signal from the ECU.

In the present embodiment, one run includes a case where the travel distance is 0 (for example, when only an air conditioner mounted on a vehicle is used).
That is, in the present embodiment, the travel time E is not the time when the vehicle actually travels, but the time from when the vehicle is started until the vehicle is terminated.

  As shown in FIG. 2, the storage unit 13 stores a reference matrix M1, a determination value matrix M2, a coefficient matrix M3, and the like whose rows and columns are defined by the average discharge current value A and the travel distance D. That is, the average discharge current value A and the range of the travel distance D are set in the rows and columns of the respective matrices M1 to M3 (reference symbols A1 to A2 and A2 to A3 and A3 to A4 and reference symbols D1 to D1 shown in FIG. 2). D2, D2-D3, D3-D4). The storage unit 13 is configured by, for example, a commercially available HDD (Hard Disk Drive).

As shown in FIG. 2A, the reference matrix M1 stores past accumulated data L11, L12,... As elements (that is, matrix values corresponding to the average discharge current value A and the travel distance D).
That is, the reference matrix M1 stores past accumulated data L11, L12,... According to the average discharge current value A and the travel distance D.

  The past accumulated data L11, L12... Is a determination index F calculated in the past examination. That is, the past accumulated data L11, L12,...

The past inspection includes not only an inspection performed in the past with the vehicle of the present embodiment but also an inspection performed with another vehicle.
In other words, the past accumulated data L11, L12,... Are calculated, for example, by the judgment index calculated by the test conducted on the same vehicle type as the vehicle and by the test performed when actually traveling. It may be a judgment index or the like.

  As shown in FIG. 2B, the determination value matrix M2 stores determination values J11, J12... As elements.

  The determination values J11, J12,... Are values used when determining whether the secondary battery 21 is short-circuited. For example, the maximum value of the determination index F assumed before the short-circuit is set. The judgment values J11, J12,... Are set in advance before performing a short circuit inspection.

  As shown in FIG. 2C, the coefficient matrix M3 stores coefficients K11, K12,... As elements.

  The coefficients K11, K12,... Are values used when updating the determination values J11, J12,. The coefficients K11, K12,... Are set in advance before performing a short circuit inspection.

As shown in FIG. 2, the same average discharge current value A and the same travel distance D range are set in the rows and columns of the matrices M1 to M3.
Accordingly, when each of the matrices M1 to M3 is searched using the predetermined average discharge current value A and the travel distance D as keys, each element at the same position (for example, past accumulated data L32, determination value J32, coefficient K32) is applicable. Will be.

  In this way, the short-circuit inspection method creates the reference matrix M1 before performing the short-circuit inspection, and calculates the determination values J11, J12,... In advance for each past accumulated data L11, L12,. Doing the steps.

  As shown in FIG. 1, the output unit 14 is for notifying the driver that a short circuit of the secondary battery 21 has been detected. The output unit 14 is configured by, for example, lighting for notifying a short circuit of the secondary battery 21 or installing a buzzer in the vehicle.

  The calculation unit 15 performs a calculation process using the determination index F and the like to inspect for a short circuit of the secondary battery 21. The calculating part 15 is comprised by CPU (Central Processing Unit) etc., for example.

  The calculation unit 15 is electrically connected to the battery information acquisition unit 11 and the vehicle information acquisition unit 12, and based on the signals input from the battery information acquisition unit 11 and the vehicle information acquisition unit 12, the average discharge current value A, cumulative The discharge current value B, the discharge time C, the travel distance D, and the travel time E are acquired.

  The calculation unit 15 is electrically connected to the storage unit 13 and outputs a signal to the storage unit 13 to search each matrix M1 to M3 using the average discharge current value A and the travel distance D as keys, and corresponds to the key. Get the element to be.

  The computing unit 15 is electrically connected to the output unit 14 and operates the output unit 14 by outputting a signal to the output unit 14.

Next, the procedure of the short circuit inspection method will be described.
First, the procedure of the short circuit inspection method when the secondary battery 21 is not short-circuited will be described.

  In the short circuit inspection method, the short circuit inspection apparatus 10 is operated to inspect the short circuit of the secondary battery 21 after the vehicle travels.

  In addition, the timing which test | inspects a short circuit is not restricted to this embodiment. That is, the short circuit inspection method may inspect the short circuit of the secondary battery 21 before the vehicle starts to travel.

  As shown in FIG. 3, the short circuit inspection method includes the average discharge current value A, cumulative discharge current value B, and discharge time C of the battery pack 20 and the travel distance of the vehicle in one (current) travel of the vehicle. A step of acquiring D and travel time E is performed (step S10).

  At this time, as shown in FIG. 1, the short circuit inspection apparatus 10 inputs the average discharge current value A, the cumulative discharge current value B, and the discharge time C from the battery information acquisition unit 11 to the calculation unit 15 and acquires vehicle information. The travel distance D and travel time E are input to the calculation unit 15 from the unit 12.

  As shown in FIG. 3, after acquiring the average discharge current value A and the like, the short circuit inspection method acquires a determination value (step S20).

  At this time, as shown in FIG. 1 and FIG. 2B, the calculation unit 15 searches the determination value matrix M2 using the current average discharge current value A and travel distance D (obtained in step S10) as keys. . And the calculating part 15 acquires the determination value applicable to the said key (refer code | symbol J shown in FIG. 1).

Here, when traveling for a short distance using only the electric power of the battery pack 20, the average discharge current value A increases and the traveling distance D decreases.
On the other hand, when the battery pack 20 and a fuel such as gasoline are used for long distance travel, the average discharge current value A decreases and the travel distance D increases.

  In the rows and columns of the respective matrices M1 to M3, ranges of the average discharge current value A and the travel distance D are set in accordance with how the vehicle is used.

  That is, in step S20, the short circuit inspection method determines how to use the vehicle based on the current average discharge current value A and the travel distance D, and acquires a determination value corresponding to the determined usage of the vehicle.

  In the following, it is assumed that traveling is performed for a short distance using only the electric power of the battery pack 20 and the determination value J32 is acquired.

  As shown in FIG. 3, after acquiring the determination value J32, the short circuit inspection method confirms whether or not the current traveling time E is equal to or longer than a certain time (step S30).

  At this time, the calculation unit 15 compares the travel time E threshold value stored in the storage unit 13 in advance with the current travel time E to check whether the current travel time E is equal to or greater than the travel time E threshold value. To do.

  If the current travel time E is less than a certain time, the short circuit inspection method ends the short circuit inspection (No in step S30).

Two peaks of the frequency distribution as shown in FIG. 13B appear prominently by frequency distribution of the determination index F when the traveling time E is a certain time.
Therefore, the short-circuit inspection method of the present embodiment improves the inspection accuracy by excluding the acquired data A to E when the travel time E is a short time.

  On the other hand, when the current travel time E is equal to or longer than a certain time, the short circuit inspection method calculates the determination index F and stores the calculated determination index F in the reference matrix M1 (step S30: Yes, step S40).

At this time, the calculation unit 15 divides the current accumulated discharge current value B by the discharge time C to calculate the current determination index F.
Then, as shown in FIGS. 1 and 2A, the calculation unit 15 searches the reference matrix M1 using the current average discharge current value A and the travel distance D as keys, and the past accumulated data L32 corresponding to the key. In addition, the current determination index F is added.

As a result, the short-circuit inspection method adds the current determination index F to the past accumulated data L32 that has been used in the past.
That is, in the short circuit inspection method, the determination index F is accumulated in the reference matrix M1 according to how the vehicle is used.

Step S40 in this embodiment corresponds to a step of calculating the determination index F by dividing the cumulative discharge current value B by the discharge time C.
In step S40 in the present embodiment, the determination index F calculated in the current inspection is added to the past accumulated data L32 of the reference matrix M1 corresponding to the average discharge current value A and the travel distance D acquired in the current inspection. It corresponds to a step.

As shown in FIGS. 3 and 4, after the determination index F is calculated, the short circuit inspection method acquires the past accumulated data L32 and frequency-distributes the acquired determination index F with a certain number of grades (step S50). ).
That is, in the short circuit inspection method, the past accumulated data L32 including the current determination index F is frequency-distributed.

At this time, as shown in FIG. 1 and FIG. 4, the calculation unit 15 searches the reference matrix M1 using the current average discharge current value A and the travel distance D as keys, and acquires the past accumulated data L32 corresponding to the key. (Refer to symbol L shown in FIG. 1).
Then, the calculation unit 15 includes a fixed number (in this embodiment, five in the present embodiment) so that the maximum value of the past accumulated data L32 is included in the highest grade T5 and the minimum value of the past accumulated data L32 is included in the lowest grade T1. Grade). Thereafter, the calculation unit 15 counts the number of past accumulated data L32 corresponding to the respective grades T1 to T5 and creates a frequency distribution.

The past accumulated data L32 including the current determination index F is a determination index calculated from the accumulated discharge current value B and the discharge time C before the short circuit. Further, the past accumulated data L11, L12,... Are stored according to how the vehicle is used.
Therefore, when the secondary battery 21 is not short-circuited, the short-circuit inspection method creates a frequency distribution in which one peak is formed.

  As shown in FIGS. 3 and 5, after the determination index F is frequency-distributed, the short circuit inspection method confirms whether or not the current determination index F has been counted to a higher grade (step S <b> 60).

In the present embodiment, the higher grade is assumed to be a grade T4 · T5 that is higher than the grade (grade T2 · T3 in FIG. 5) that is the peak of the created frequency distribution.
However, a high grade is not restricted to this, For example, only the highest grade T5 may be sufficient. That is, the higher grade may be one grade of the highest grade or a plurality of grades that are consecutive from the highest grade. Such a high grade is appropriately set according to the number of grades of the frequency distribution.

The frequency distribution shown on the upper side of FIG. 5 is a frequency distribution of the past accumulated data L32 up to the previous examination. The frequency distribution shown on the lower side of FIG. 5 is obtained by frequency-distributing past accumulated data L32 including the current determination index F.
In the following description, it is assumed that the current determination index F is counted as the grade T3 (see the white dots in FIG. 5).

  As described above, when the secondary battery 21 is short-circuited, the result of dividing the cumulative discharge current value B by the discharge time C, that is, the determination index F becomes larger than that before the short-circuit. Therefore, when the secondary battery 21 is short-circuited, it is assumed that the determination index F is counted as a high grade T4 / T5.

  Therefore, as shown in FIG. 3 and FIG. 6, when the current determination index F is not counted in the high grade T4 / T5, the short circuit inspection method determines that the secondary battery 21 is not short-circuited, and this time An average value H of the frequency distribution of the past accumulated data L32 including the determination index F is calculated (step S60: No, step S70).

At this time, the calculation unit 15 includes the middle point of each of the grades T1 to T5 of the frequency distribution (that is, a value that is intermediate between the ranges of the respective grades T1 to T5) and the past accumulated data L32 counted in each of the grades T1 to T5. Accumulate the number of.
And the calculating part 15 adds up the integration result of each grade T1-T5, and divides the number of the whole past accumulation data L32 from the said addition result, and calculates the average value H of frequency distribution.

  Note that the short-circuit inspection method does not necessarily calculate the average value H of the frequency distribution. For example, the simple average value of the past accumulated data L32 (the sum of the values of the past accumulated data L32 is divided by the total number of the past accumulated data L32). The result may be calculated.

  As described above, the short-circuit inspection method performs step S70 of calculating the average value H (for example, the average value or simple average value of the frequency distribution) of the past accumulated data L32 including the determination index F calculated in the current inspection.

As shown in FIG. 3, after calculating the average value H of the frequency distribution, the short circuit inspection method updates the determination value J32 corresponding to the current average discharge current value A and the travel distance D using the coefficient K32. (Step S80).
That is, in the short circuit inspection method, the maximum value of the determination index F assumed before the short circuit is estimated from the average value H and the coefficient K32 of the frequency distribution, and the estimation result is set as the determination value J32.

At this time, as shown in FIG. 7, the calculation unit 15 searches the coefficient matrix M3 using the current average discharge current value A and the travel distance D as keys, and acquires the coefficient K32 corresponding to the key (see FIG. 1). (See reference sign K). Then, the calculation unit 15 integrates the average value H of the frequency distribution and the coefficient K32.
Thereafter, as shown in FIG. 8, the calculation unit 15 searches the determination value matrix M2 using the current average discharge current value A and the travel distance D as keys, and the determination value J32 corresponding to the key is the average of the frequency distribution. Update so that the result of integration of the value H and the coefficient K32 is obtained.

  As described above, the short-circuit inspection method integrates the calculation result of the average value H of the past accumulated data L32 and the coefficient K32 set in advance according to the average discharge current value A and the travel distance D, thereby performing the current inspection. Step S80 for updating the average discharge current value A and the determination value J32 corresponding to the travel distance D acquired in step S80 is performed.

  In the short-circuit inspection method, the determination value J32 may be updated before the current determination index F is added to the reference matrix M1.

  As shown in FIG. 3, the short circuit inspection method ends the short circuit inspection after updating the determination value J32.

The short-circuit inspection method of this embodiment repeatedly performs such inspection until the secondary battery 21 is short-circuited.
Thereby, the short circuit inspection method accumulates the judgment index F before the short circuit as the past accumulated data L11, L12,... According to the usage of the vehicle, and the frequency distribution of the past accumulated data L11, L12,. A peak is formed (see FIG. 4).

  Next, the procedure of the short circuit inspection method when the secondary battery 21 is short-circuited will be described.

  The procedure from obtaining the average discharge current value A and the like to calculating the determination index F (steps S10 to S40) is the same as the procedure when the secondary battery 21 is not short-circuited. For this reason, description of step S10-S40 is abbreviate | omitted below.

  In the following description, after the vehicle is driven in the same manner as the above-described inspection in the case where the secondary battery 21 is not short-circuited, that is, after the battery pack 20 is traveled only for a short distance, The short circuit of the battery 21 shall be inspected.

  As described above, when the secondary battery 21 is short-circuited, the determination index F increases. When the secondary battery 21 is not short-circuited in the previous inspection, the past accumulation data L32 up to the previous inspection does not include such a determination index F when short-circuited (shown on the upper side of FIG. 9). Frequency distribution).

  Therefore, as shown in FIGS. 3 and 9, in the short circuit inspection method, the past accumulated data L32 in which the current determination index F is the largest among the past accumulated data L32 is frequency-distributed (step S50).

At this time, the calculation unit 15 performs a certain number of grades so that the current determination index F is included in the highest grade T5.
Therefore, the current determination index F is counted as the highest grade T5 (see the white dots in the lower frequency distribution in FIG. 9).

  As described above, when the current determination index F is counted to the highest grade T5, the short-circuit inspection method confirms whether it has been counted to the higher grade T4 · T5 continuously for the designated number of times (step S60: Yes, step S90). ).

  At this time, the calculation unit 15 calculates the number of times that the determination index F is continuously counted to the higher grades T4 and T5, and confirms whether the calculation result is equal to or greater than the threshold value of the count stored in the storage unit 13 in advance. To do.

As shown in FIGS. 5 and 9, the number of times that the determination index F is continuously counted to the higher grades T4 and T5 is one.
In this case, as shown in FIG. 3, in the short circuit inspection method, the average value H of the frequency distribution is calculated and the determination value J32 is updated (step S90: No, step S70, step S80), similarly to the inspection before the short circuit. ).

  After the determination value J32 is updated, the short circuit inspection method ends the first inspection after the short circuit.

As shown in FIGS. 3, 10, and 11, even in the second and subsequent inspections after the short circuit, the determination index F is larger than that before the short circuit and is counted as a higher grade T4 / T5 (FIG. 10). Also, see the points shown in white in the frequency distribution on the lower side of FIG. 11).
For this reason, the short-circuit inspection method confirms whether or not the second and subsequent inspections after the short circuit have been counted in the higher grades T4 and T5 continuously after performing Steps S10 to S60 (Step S4). S90).

  In the short circuit inspection method of this embodiment, the designated number of times in step S90 is set to three. For this reason, in the short circuit inspection method, it is determined that the determination index F has been counted in the higher grades T4 and T5 for the designated number of times in the third inspection after the short circuit (step S90: Yes).

Even if the vehicle is run in a different usage after a short circuit and a short circuit is inspected, the judgment index F in the first to third inspections after the short circuit is the past accumulated data L11 and L12 corresponding to each usage. In the frequency distribution of..., It is counted as a high grade.
For this reason, in step S90, it is confirmed whether the determination index F in the immediately preceding inspection is continuously counted to a higher grade regardless of how the vehicle is used.

As shown in FIG. 3 and FIG. 12, when the determination index F is counted to the higher grades T4 and T5 for the designated number of times, the short circuit inspection method compares the determination index F with the determination value J32 (step S90: Yes, step S100).
As described above, the determination value J32 is a maximum value of the determination index F assumed before the short circuit, that is, a value between two peaks formed by the determination index F before and after the short circuit.

  Therefore, when the determination index F in the third inspection after the short circuit is larger than the determination value J32, the short circuit inspection method determines that the secondary battery 21 is short-circuited and notifies the driver of the fact (step). S100: Yes, Step S110, Step S120).

  At this time, the arithmetic unit 15 inputs a predetermined signal to the output unit 14 to operate the output unit 14.

On the other hand, when the determination index F in the third inspection after the short circuit is the determination value J32 or less, the short circuit inspection method determines that the secondary battery 21 is not short-circuited, and the frequency distribution is similar to the inspection before the short circuit. The average value H is calculated, and the determination value J32 is updated (step S100: No, step S70, step S80).
That is, in this case, the short-circuit inspection method determines that the determination index F is counted to the higher grades T4 and T5 for the designated number of times in a state where the secondary battery 21 is not short-circuited.

  In this way, the short-circuit inspection method uses the determination index F (current amount per unit time) calculated in the current inspection as the determination value J32 corresponding to the average discharge current value A and the travel distance D acquired in the current inspection. Based on the comparison result, step S100 is performed to determine whether the secondary battery 21 is short-circuited.

According to this, the short circuit test | inspection method can detect the short circuit of the secondary battery 21 based on the information when using a vehicle.
That is, the short circuit inspection method can inspect the short circuit of the secondary battery 21 without using equipment (for example, a temperature-controlled room or charging / discharging means) for acquiring information necessary for short circuit inspection. That is, the short-circuit inspection method does not require the secondary battery 21 to be left and constantly monitored, so that it is not necessary to separately use energy (external power source or spare battery) for the short-circuit inspection.

Thereby, the short circuit inspection method can reduce the cost required for the inspection of the short circuit and improve the merchantability of the vehicle.
Moreover, the short circuit inspection method can test | inspect the short circuit of the secondary battery 21 after shipment easily.

When the secondary battery 21 is short-circuited due to an internal chemical reaction or the like during use, the degree of voltage drop when the secondary battery 21 is left is gradually increased as the secondary battery 21 is short-circuited. Become.
Therefore, when such a secondary battery 21 is inspected based on the degree of voltage drop, there is a possibility that the short circuit cannot be detected unless the short circuit proceeds to some extent.

  On the other hand, the cumulative discharge current value B and the discharge time C, that is, the determination index F is a value that is large enough to exceed the determination index F assumed before the short circuit even when the short circuit of the secondary battery 21 has not progressed much. Become.

  Therefore, the short circuit inspection method can detect the short circuit of the secondary battery 21 accurately and promptly even when the short circuit of the secondary battery 21 proceeds due to an internal chemical reaction or the like during use.

The battery pack 20 mounted on the vehicle is generally provided with an equalization circuit for aligning the voltages of the secondary batteries 21.
Therefore, when a short circuit is inspected based on the voltage drop degree, the voltage drop degree cannot be calculated accurately, and as a result, there is a possibility that the short circuit cannot be detected accurately.

  On the other hand, since the short circuit inspection method can inspect the short circuit of the secondary battery 21 without acquiring the voltage value of the secondary battery 21, even when the equalization circuit is provided in the battery pack 20, the short circuit of the secondary battery 21 is performed. Can be detected accurately.

  As described above, the short circuit inspection method can accurately detect a short circuit of the secondary battery 21 mounted on the vehicle.

If each secondary battery 21 is connected in parallel, the short-circuit inspection method obtains the average discharge current value A, the cumulative discharge current value B, and the discharge time C of each secondary battery 21 to obtain each secondary battery 21. The short circuit inspection as described above is performed for each battery 21.
That is, when the secondary batteries 21 are connected in series as in the present embodiment, the average discharge current value A, the cumulative discharge current value B, and the discharge time C of the battery pack 20 are the secondary batteries according to the present invention. Correspond to the average discharge current value, the cumulative discharge current value, and the discharge time.

Here, even when the usage of the vehicle is the same, there is a possibility that the usage of the secondary battery 21 during traveling may change depending on the driver's bag and the driving area.
That is, even when the vehicle is driven with a fixed usage, the determination index F may vary depending on the driver and the driving area.

  Therefore, when the judgment value J32 is set as a fixed value using the past accumulated data L32 when a single driver travels in a certain area, the driving area changes. In addition, there is a possibility that the determination value J32 does not become a value between two peaks (see FIG. 12) formed before and after the short circuit.

Therefore, the short-circuit inspection method reflects the current determination index F in the determination value J32 in step S80.
Thereby, the short circuit inspection method can learn the fluctuation | variation of the judgment parameter | index F resulting from a driver | operator's bag and the area to drive. Therefore, the short-circuit inspection method can set the optimum determination values J11, J12,... According to the driver's habit and the driving area.

According to this, since the determination value J32 can always be set to an optimum value even when the driver or the driving region is different, the short circuit inspection method can accurately detect the short circuit of the secondary battery 21.
That is, the short-circuit inspection method can improve inspection accuracy by updating the determination values J11, J12.

In addition, the short circuit inspection method does not necessarily need to confirm whether it was counted to high grade T4 * T5. That is, in the short circuit inspection method, immediately after the determination index F is calculated, the determination index F may be compared with the determination value J32 to determine whether the secondary battery 21 is short-circuited.
However, it is possible to reduce the man-hours necessary for setting the coefficients K11, K12... And to prevent erroneous detection when the determination index F temporarily becomes higher than the determination value J32 due to a factor other than a short circuit. From the viewpoint, it is preferable to confirm whether the short-circuit inspection method has been counted as high grades T4 and T5.
Thereby, the short circuit inspection method can reduce the man-hours required for preparation and improve the inspection accuracy.

21 Secondary battery A Average discharge current value B Cumulative discharge current value C Discharge time D Traveling distance F Judgment index J32 Judgment value L32 Past accumulated data M1 Reference matrix

Claims (2)

A method for inspecting a short circuit of a secondary battery mounted on a vehicle, comprising:
Obtaining a mean discharge current value, a cumulative discharge current value, a discharge time, and a travel distance of the vehicle in a single run of the vehicle;
Dividing the cumulative discharge current value by the discharge time to calculate a determination index;
A reference matrix that is stored according to the average discharge current value and the travel distance is created using the determination index calculated in the past inspection as past accumulated data, and a determination value is calculated in advance for each past accumulated data of the reference matrix. Steps,
A step of determining a short circuit of the secondary battery based on a result of comparing the determination index calculated in the current inspection with the average discharge current value acquired in the current inspection and the determination value corresponding to the travel distance. When,
I do,
Secondary battery short-circuit inspection method. Adding the determination index calculated in the current inspection to the past accumulated data of the reference matrix corresponding to the average discharge current value and the travel distance acquired in the current inspection;
Calculating an average value of the past accumulated data including the judgment index calculated in the current examination;
The average discharge current value obtained in the current inspection and the travel are obtained by integrating the calculation result of the average value of the past accumulated data and the coefficient set in advance according to the average discharge current value and the travel distance. Updating the determination value corresponding to the distance;
Do further,
The short circuit inspection method of the secondary battery according to claim 1.

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