JP2014082120A - System for reusing nonaqueous electrolyte secondary battery - Google Patents

Abstract

An object of the present invention is to accurately determine whether or not to reuse a non-aqueous electrolyte secondary battery.
A non-aqueous electrolyte secondary battery recycling system according to the present invention includes a first acquisition unit that acquires a first measurement value obtained by measuring a production amount of a lithium fluoride film generated on a positive electrode; A first storage unit that holds the first range of the obtained lithium fluoride film generated on the positive electrode, and a first determination unit that determines whether or not to reuse the target battery based on the first measurement value and the first range; Is provided. In addition, a second acquisition unit that acquires a second measurement value obtained by measuring the electrical resistance, a second storage unit that holds a second range relating to electrical resistance, which is obtained in advance, and the second measurement value are the second range. The second determination unit that causes the first determination unit to determine whether or not the target battery is to be reused.
[Selection] Figure 1

Description

  The present invention relates to a reuse system and a reuse method determination method for a non-aqueous electrolyte secondary battery, and more particularly to a method for determining whether a battery is reused.

Reuse of non-aqueous electrolyte secondary batteries has different resource costs depending on the method. In general, reusing (reusing) a nonaqueous electrolyte secondary battery to be reused has a lower resource cost than dismantling and recycling (recycling).
As a method for determining the suitability of reuse, a method based on the rate of change in electrical resistance of a secondary battery due to repeated use is known. For example, Patent Document 1 discloses a system for classifying and reusing a test battery from the rate of change in electrical resistance.

JP 2007-141464 A

The technique described in Patent Document 1 can smoothly reuse a secondary battery. However, if the change rate of the electrical resistance of the test battery is small, it may not be possible to appropriately determine whether or not to reuse.
The present invention has been made to solve such problems. That is, the present invention provides a reuse system and a reuse method determination method that can accurately determine whether or not a non-aqueous electrolyte secondary battery can be reused even under conditions where the change rate of the electrical resistance of the secondary battery is small. Objective.

  The non-aqueous electrolyte secondary battery recycling system of the present invention has a first acquisition unit that acquires a first measurement value obtained by measuring the amount of lithium fluoride coating produced on the positive electrode, A first storage unit that holds a first range of a lithium fluoride film generated on the positive electrode, and a first determination unit that determines whether or not to reuse the target battery based on the first measurement value and the first range. Prepare.

  The non-aqueous electrolyte secondary battery recycling system of the present invention maintains a second acquisition unit that acquires a second measurement value obtained by measuring electric resistance, and a second range relating to electric resistance that is obtained in advance. And a second determination unit that causes the first determination unit to determine whether or not to reuse the target battery when the second storage value and the second measurement value belong to the second range. .

  The production amount is a production amount of a lithium fluoride coating formed on a positive electrode of a test battery that is a non-aqueous electrolyte secondary battery, and the first range is determined in advance for a non-aqueous electrolyte secondary battery. A range relating to the amount of lithium fluoride coating produced on the positive electrode is preferred. The second measurement value is a measurement value obtained by measuring the electric resistance of the test battery, and the second range is a range relating to the electric resistance of the non-aqueous electrolyte secondary battery obtained in advance. It is preferable.

  The first range is obtained in advance from first correlation data relating to the amount of lithium fluoride coating formed on the positive electrode of the non-aqueous electrolyte secondary battery and the electrical resistance of the non-aqueous electrolyte secondary battery, and the first range. It is preferable to be obtained based on the third range relating to the electrical resistance of the non-aqueous electrolyte secondary battery. Moreover, it is preferable that the first correlation data is a regression line of the amount of the lithium fluoride film obtained in advance and the electric resistance of the nonaqueous electrolyte secondary battery obtained in advance.

  The non-aqueous electrolyte secondary battery recycling system of the present invention includes a predetermined use schedule of a non-aqueous electrolyte secondary battery and the amount of lithium fluoride coating produced on the positive electrode of the non-aqueous electrolyte secondary battery. And a second storage unit for storing the second correlation data, and the first determination unit, based on the first measurement value, the first range, and the second correlation data, It is preferable to further include an estimation unit that estimates a usable schedule, and an auxiliary determination unit that determines whether or not the target battery is to be reused based on the remaining usable schedule.

It is preferable that the use schedule is an elapsed period from the start of use of the nonaqueous electrolyte secondary battery, which is obtained in advance, and the usable schedule is a remaining usable period of the test battery.
Further, the non-aqueous electrolyte secondary battery recycling system of the present invention is obtained in advance, with a third acquisition unit for acquiring a third measurement value obtained by measuring the use environment temperature of the test battery, A fourth storage unit for holding third correlation data relating to a use environment temperature of the non-aqueous electrolyte secondary battery and a generation rate of the lithium fluoride coating on the positive electrode of the non-aqueous electrolyte secondary battery. The unit preferably further estimates the remaining usable period based on the third measurement value and the third correlation data.

  The target battery is preferably another battery belonging to the battery assembly to which the test battery belongs.

  The method for determining the reuse method of a non-aqueous electrolyte secondary battery according to the present invention includes a first acquisition step of acquiring a first measurement value obtained by measuring a production amount of a lithium fluoride coating produced on a positive electrode, and the first A first determination step of determining whether or not to reuse the target battery based on the measured value and a first range of the lithium fluoride film generated on the positive electrode, which is obtained in advance;

  The non-aqueous electrolyte secondary battery reuse method determination method includes a second acquisition step of acquiring a second measurement value obtained by measuring electric resistance, and a case where the second measurement value belongs to the second range. Preferably, the method further includes a second determination step that causes the first determination unit to determine whether or not the target battery is to be reused.

  It is possible to provide a reuse system and a reuse technique determination method capable of accurately determining whether or not a non-aqueous electrolyte secondary battery is reused.

It is a figure which shows the reuse system which concerns on embodiment. It is a graph which shows the relationship between the usage days of a secondary battery, and a resistance increase rate. It is a graph which shows typically the relation between the use days of a secondary battery, and a resistance increase rate. It is a graph which shows typically the relation between the use days of a secondary battery, and the amount of coat production. It is a graph which shows the remaining usable period typically. It is a figure which shows the flow of the determination process with respect to a to-be-tested cell. It is a figure which shows the flow of the determination process based on the amount of LiF film with respect to a test cell. It is a figure which shows the reuse system which concerns on a modification. It is a graph which shows the relationship between the remaining usable period and an electrical resistance. It is a graph which shows the relationship between the remaining usable period and the amount of film production. It is a graph which shows the relationship between an electrical resistance and a film production amount. It is a graph which shows the relationship between battery use environmental temperature and a film production | generation speed | rate.

Embodiments of the present invention will be described below with reference to the drawings.
<Outline of the embodiment>

  The non-aqueous electrolyte secondary battery reuse technique determination method according to the embodiment of the present invention is a method for determining a reuse technique of a collected used battery. The non-aqueous electrolyte secondary battery reuse system according to the embodiment of the present invention is mainly electronic means for carrying out the above-described method. In the following embodiments and examples, a lithium ion secondary battery will be described as a test object.

The reuse system and the reuse method determination method according to the present embodiment can be suitably used for non-aqueous electrolyte secondary batteries that produce a lithium fluoride coating on the positive electrode. Examples of such non-aqueous electrolyte secondary batteries include, but are not limited to, those having lithium hexafluorophosphate (LiPF ₆ ) in the electrolyte.

<Reuse system>
As shown in FIG. 1, the reuse system 1 includes a resistance determination module 20, an acquisition module 10, a storage module 30, and a cell determination unit 40. The resistance determination module 20 includes a resistance value acquisition unit 21, a latent resistance range storage unit 22, and a resistance determination unit 23. Details of each component will be described later.

  The acquisition module 10 includes a film value acquisition unit 11 that is a first acquisition unit. The coating value acquisition unit 11 acquires a measured coating value that is a first measurement value obtained by measuring the amount of lithium fluoride coating produced on the positive electrode. The acquisition module 10 may further include a temperature value acquisition unit 12. Details of each component will be described later.

  The storage module 30 includes a film range storage unit 31 that is a first storage unit. The film range storage unit 31 holds a film range, which is a first range of the lithium fluoride film generated on the positive electrode, which is obtained in advance. The storage module 30 may further include a film pair schedule data storage unit 32 and a temperature versus speed data storage unit 33. Details of each component will be described later.

  The cell determination unit 40 determines the suitability for reuse of the target battery, which is a judgment target for suitability for reuse, based on the measured coating value and the coating range. The cell determination unit 40 includes an estimation unit 41 and an auxiliary determination unit 42. When the reuse system has the above-described configuration, it is possible to predict whether or not the reuse is appropriate with little variation and high accuracy.

Each element will be described in more detail with reference to FIG.
The resistance value acquisition unit 21 (second acquisition unit) is an acquisition unit that acquires the measurement resistance value (second measurement value) of the test cell. The measured resistance value is a resistance value obtained by measuring the IV resistance between the positive electrode terminal and the negative electrode terminal of the cell. The resistance value acquisition unit 21 sends the measured resistance value to the resistance determination unit 23.

  The IV resistance is obtained by measuring each voltage value when a battery is charged or discharged at a plurality of current values for a fixed time, plotting each current value and voltage value, and calculating the slope of the voltage value with respect to the current value. It is the value of electrical resistance. The value of the IV resistance is an index for knowing how much current can flow through the battery.

  The latent resistance range storage unit 22 (second storage unit) is a storage unit that holds a latent resistance range (second range) obtained in advance. The latent resistance range is a predetermined range of the IV resistance of the battery obtained in advance. The predetermined range is preferably less than or equal to a resistance value at which an increase in the electric resistance of the battery with the repeated use of the battery becomes apparent.

By setting it as this range, the resistance determination part 23 can determine appropriately the battery in which degradation has progressed potentially. The calculation mode of the film range based on the latent resistance range will be described later.
The latent resistance range storage unit 22 sends the latent resistance range to the resistance determination unit 23 in response to a request from the resistance determination unit 23.

  The resistance determination unit 23 (second determination unit) causes the cell determination unit to determine whether or not to reuse the target battery when the measured resistance value belongs to the latent resistance range (second range) obtained in advance. It is. The resistance determination unit 23 receives the measured resistance value from the resistance value acquisition unit 21. The resistance determination unit 23 requests the latent resistance range storage unit 22 to transmit the latent resistance range and receives the latent resistance range.

When the measured resistance value is in the potential resistance range, the resistance determination unit 23 determines that it is necessary to determine whether or not the reuse is appropriate based on the LiF coating amount of the test cell. Further, the determination result is sent to a display unit (not shown), and the user is prompted to sample the test cell necessary for determining whether or not the cell can be reused based on the LiF coating amount. The resistance determination unit 23 further sends a redetermination command to the estimation unit 41 of the cell determination unit 40. The re-determination command is a command for determining whether or not to reuse the cell based on the LiF coating amount.
When the measured resistance value is not in the latent resistance range, the resistance determination unit 23 determines that it is possible to determine whether or not to reuse the resistance.

The coating value acquisition unit 11 (first acquisition unit) is an acquisition unit that acquires the measurement coating value (first measurement value) of the test cell. The measured coating value is obtained by measuring the amount of lithium fluoride coating produced on the test cell that is a nonaqueous electrolyte secondary battery, that is, the positive electrode of the test battery (hereinafter referred to as LiF coating amount). It is.
The battery referred to in this embodiment includes a positive electrode, a negative electrode, and an electrolyte, and supplies power. Unless otherwise specified, the battery refers to a nonaqueous electrolyte secondary battery. A cell is the smallest unit of a battery that cannot be divided, and includes a positive electrode, a negative electrode, and an electrolyte as constituent elements.

  As the amount of LiF film, the thickness, volume and weight of the positive electrode film containing LiF, the weight of LiF contained in the positive electrode film, the content (volume unit or weight unit), and the number of moles (area unit of the film, volume) Unit or weight unit) can be used. From the viewpoint of calculating the film threshold value with high accuracy, the number of moles of LiF per film area of the positive electrode is preferably used.

  From the viewpoint of improving the determination accuracy, the measured coating value is preferably an average value of the measured values of the LiF coating amount of a part of the electrode sampled from a plurality of locations in the test cell or the battery assembly to which it belongs. . A battery assembly is a battery that is assembled into a larger battery. An assembly (pack) of battery assemblies (stack) is also a battery assembly. The sampling method will be described later. The coating value acquisition unit 11 sends the measured coating value to the estimation unit 41 of the cell determination unit 40.

The temperature value acquisition unit 12 (third acquisition unit) is an acquisition unit that acquires the measured temperature value (third measurement value) of the test cell. The measured temperature value is a time average value of temperatures obtained by measuring the use environment temperature of the test cell. The time average value may be a time average related to an accumulated usage time or an elapsed period. The average time or period length may be the total accumulated usage time or the elapsed period, or may be divided into a predetermined length. When dividing into predetermined length, you may take an average in the time or period of the nearest predetermined length at the time of determination of the propriety of reuse.
The temperature value acquisition unit 12 sends the measured temperature value to the estimation unit 41 of the cell determination unit 40.

  The coating range storage unit 31 (first storage unit) is a storage unit that holds the coating range (first range). The coating range is a desirable range of the LiF coating amount determined in advance. The range of the LiF coating amount is preferably set to a predetermined coating threshold value or less.

  The film threshold is preferably determined based on LiF conversion data obtained in advance, that is, first correlation data, and an allowable resistance range obtained in advance, that is, the third range. The LiF conversion data is correlation data between the LiF coating amount and the electric resistance of the cell, obtained in advance. The LiF conversion data can be a regression line of the generation amount of the lithium fluoride coating obtained in advance and the electrical resistance of the non-aqueous electrolyte secondary battery obtained in advance.

The allowable resistance range is a desirable range of the IV resistance of the cell obtained in advance. The allowable resistance range is preferably set to be equal to or less than the resistance threshold of the cell in which cell reuse is allowed. By setting it as this range, the cell determination part 40 can calculate a desirable film range correctly. The calculation mode of the film range based on the allowable resistance range will be described later.
The coating range storage unit 31 sends the coating range to the estimation unit 41 in response to a request from the estimation unit 41 of the cell determination unit 40.

  The film pair schedule data storage unit 32 (third storage unit) is a storage unit that holds LiF transition data (second correlation data) obtained in advance. The LiF transition data is correlation data between the battery use schedule and the LiF coating amount, which is obtained in advance.

  The usage schedule starts from the start of battery use. The start of use may be when charging / discharging for the first time or when power is first supplied to an automobile, machine, or instrument that requires power. Further, it may be the first time an automobile or the like is used after the battery to be examined is mounted. Further, the batteries may be accumulated as long as they are reused once or more.

  The usage schedule can be an elapsed period from the start of use of the non-aqueous electrolyte secondary battery, which is obtained in advance. The elapsed period is the total time including the charging time, the discharging time, and the no discharging time or the spontaneous discharging time. The elapsed period may be in seconds, minutes, hours, days, weeks, or years.

The LiF transition data can be a regression line of the LiF coating amount obtained in advance and the square root of the elapsed period. The LiF transition data will be further described in the calculation mode of the film range described later.
The film pair schedule data storage unit 32 sends LiF transition data to the estimation unit 41 in response to a request from the estimation unit 41 of the cell determination unit 40.

  The temperature versus speed data storage unit 33 (fourth storage unit) is a storage unit that holds LiF generation rate data (third correlation data) that is obtained in advance. In particular, it is possible to prepare for a case where an elapsed period from the start of use of the nonaqueous electrolyte secondary battery, which is obtained in advance as a use schedule.

The LiF production rate data is correlation data between the use environment temperature of the non-aqueous electrolyte secondary battery and the production rate of the lithium fluoride film on the positive electrode of the non-aqueous electrolyte secondary battery, which are obtained in advance. The rate of formation of the lithium fluoride coating is the time change rate of the LiF coating amount. The LiF generation rate data will be described later in the calculation mode of the film range.
The temperature versus speed data storage unit 33 sends LiF generation rate data to the estimation unit 41 in response to a request from the estimation unit 41 of the cell determination unit 40.

  The cell determination unit 40 (first determination unit) is a determination unit that determines whether or not the non-aqueous electrolyte secondary battery (target cell) is reused based on the measured coating value and the coating range. The cell determination unit 40 includes an estimation unit 41 and an auxiliary determination unit 42.

The estimation unit 41 estimates the remaining usable schedule of the test battery based on the redetermination command, the measured coating value, the coating range, the LiF transition data, the measured temperature value, and the LiF generation rate data. The remaining usable schedule is based on the determination as to whether or not the non-aqueous electrolyte secondary battery can be reused.
The remaining usable schedule can be the remaining usable period of the test cell. The usable period is a total period including a charging time, a discharging time, and a no discharging time or a spontaneous discharging time. The usable period may be in seconds, minutes, hours, days, weeks, or years.

The estimation unit 41 receives the measured coating value sent from the coating value acquisition unit 11. The estimation unit 41 receives the measured temperature value sent from the temperature value acquisition unit 12. The estimation unit 41 requests the coating range storage unit 31 to transmit the coating range and receives the coating range. The estimation unit 41 requests the film pair schedule data storage unit 32 to transmit the LiF transition data, and receives the LiF transition data. The estimation unit 41 requests the temperature-to-speed data storage unit 33 to transmit LiF generation rate data, and receives the LiF generation rate data. The estimation unit 41 receives a re-determination command sent from the resistance determination unit 23.
The estimation unit 41 sends the remaining usable schedule to the auxiliary determination unit 42.

  The auxiliary determination unit 42 determines whether or not the target cell can be reused based on the remaining usable schedule. When the remaining usable schedule is within the predetermined range, the auxiliary determination unit 42 determines that the test cell is suitable for reuse. If the remaining usable schedule is outside the predetermined range, the auxiliary determination unit 42 determines that the subject cell needs to be recycled.

In the present embodiment, the recycling means that the constituent elements of the cell are separated and recycled as a material for a battery or other products.
In addition, the reuse according to the reuse system of the present embodiment includes methods such as reuse, reuse, and resource recycling. Recycling and use means that a part of the battery assembly is divided into small units of batteries and regenerated as a battery assembly. The reuse of the battery assembly means that the battery assembly is reused without being divided into small batteries. Reusing a battery means not to disassemble it but to use it again.

The predetermined range can be set to be equal to or greater than a predetermined threshold obtained from experiments or experience from the viewpoint of ensuring safety after reuse of the nonaqueous electrolyte secondary battery. For example, when the remaining usable schedule falls below a predetermined threshold, it can be determined that the period in which the remaining usable schedule can be safely used after reuse is shorter than the desired period.
In this case, the auxiliary determination unit 42 can determine that the measured resistance value is within the allowable resistance range and can be reused, but is not suitable for reuse.

  The auxiliary determination unit 42 receives the remaining usable schedule sent from the estimation unit 41. The auxiliary determination unit 42 sends the determination result to a display unit (not shown). Further, the auxiliary determination unit 42 may receive information of a predetermined range of the remaining usable schedule from a storage unit (not shown).

<Calculation mode of coating range>
The calculation mode of the coating range will be described with reference to FIGS. First, using FIGS. 2 to 4, the relationship between the deterioration of the battery, the electrical resistance, and the amount of the positive electrode coating will be described. Next, the calculation mode of the coating range of the present embodiment will be described with reference to FIG. 5.

  FIG. 2 shows a time transition of IV resistance in a 25 ° C. endurance test of a general lithium ion secondary battery. The vertical axis represents the electrical resistance at that time as a percentage of the initial resistance. The horizontal axis represents the square root of the number of days used. In addition, the example of the said endurance test was performed by using the cell under conditions of 25 ° C. and SOC 60% and measuring the IV resistance of the cell every 30 days.

  It is empirically known that within the range surrounded by the broken line in FIG. 2, the IV resistance decreasing period in the initial stage of use is over, potentially increasing the IV resistance, and the battery starts to deteriorate. However, since the rate of change in resistance is not stable, it is difficult to accurately calculate the tendency of resistance increase. For this reason, it is difficult to know the remaining usable period until the cell resistance threshold that allows cell reuse is reached, and it is difficult to determine the battery reuse technique.

  FIG. 3 schematically shows a change in the IV resistance of the battery as time elapses. The vertical and horizontal axes are the same as those in FIG. A range enclosed by a solid rectangle schematically represents the range of the graph of FIG. After the time when the IV resistance potentially increases, the tendency of increasing resistance becomes clear as in the range surrounded by the broken line.

FIG. 4 shows a time transition of the amount of the lithium fluoride coating film formed on the positive electrode, that is, the LiF coating amount in a 25 ° C. endurance test of a general lithium ion secondary battery. The vertical axis represents the LiF coating amount, and the horizontal axis represents the square root of the number of days used, as in FIG. In addition, the amount of LiF coating depends on the battery capacity.
A range enclosed by a solid rectangle schematically represents a range corresponding to the range of the resistance graph of FIG. The trend of increasing the amount of LiF coating is almost consistent from the beginning of use. Further, the portion indicated by the broken line in FIG. 4 shows a tendency equivalent to the tendency of increase in resistance in FIG.

  FIG. 5 shows a calculation mode of the film range. The graph in FIG. 5 represents the actual value of the electric resistance of the battery or the time transition of the amount of LiF coating on the positive electrode. The vertical axis represents the electric resistance or the LiF coating amount. The horizontal axis represents the elapsed time as the usage schedule, that is, the square root of the number of years used. The shaded range represents the usable range as a battery.

In a range where the degree of deterioration exceeds a predetermined threshold, it can be determined that recycling is necessary because the battery cannot be used safely. In a range where the degree of deterioration does not exceed the predetermined threshold, it can be determined that the battery can be used until the predetermined threshold is exceeded. A range in which the degree of deterioration does not exceed a predetermined threshold can be set as a coating range of the LiF coating amount or an allowable resistance range of electrical resistance.
The horizontal axis shows when the used batteries are collected. The period from the time of collection until it exceeds a predetermined threshold is the maximum value of the remaining usable period, and is represented as the usable years in this embodiment.

  The film range can be obtained in advance as a film threshold value from the time transition of the IV resistance obtained in advance. As shown in FIG. 3, the electrical resistance can be measured as a monotonically increasing value after a potential increase period. Moreover, the time transition of the LiF coating amount is monotonically increasing over the elapsed period. For this reason, the relationship between the electrical resistance and the amount of LiF coating can be derived by obtaining the time transition of the electrical resistance and the amount of LiF coating during the period when the increase in electrical resistance becomes apparent. Furthermore, the threshold value of the LiF film amount can be derived from the threshold value of electric resistance.

  Further, as described above, by determining whether or not reuse is appropriate based on the amount of LiF film, this can be accurately determined even when the increase rate of resistance is small. The thresholds or periods shown in the graph are theoretical, and they are reset to take into account the safety margin and the practical range of the remaining usable period, and the reuse system or reuse method judgment method It may be used.

<Method of judging reuse method of non-aqueous electrolyte secondary battery>
A method for determining the reuse method of the non-aqueous electrolyte secondary battery according to the present embodiment will be described with reference to FIGS. The determination of the reuse method is to select a desirable reuse method.

  Although the determination method using the above-described reuse system will be described, a part or all of the determination method may be performed by a method that is not automated regardless of the reuse system. In addition, the components of the reuse system described in FIG.

  FIG. 6 shows a flowchart of a reuse method determination method performed on the cells of the collected used battery assembly. Although not shown in FIG. 6, it is assumed that after an arbitrary determination result is obtained, the process returns to the first step S <b> 1 and the determination method of the reuse method for the next battery assembly is started.

  Step S1 is a resistance value acquisition step in which the resistance value acquisition unit 21 acquires the measured resistance value of the test cell, and is a second acquisition step of the reuse technique determination method. The measured resistance value is as described above. The resistance value acquiring unit 21 receives the measured resistance value from a resistance measuring device or the like, and sends the measured resistance value to the resistance determining unit 23. Next, the process proceeds to step S2.

As an example of a test cell selection method, that is, a sampling method, a case where a battery pack is targeted as a battery assembly to which the test cell belongs will be described below. First, the battery pack is disassembled, and the stack in the pack is divided into two groups, a high temperature side and a low temperature side.
Here, the stack is a collection of a plurality of cells. A pack is a collection of a plurality of stacks, and is mounted on and connected to an automobile, machine, or appliance that requires electric power.

  Next, each cell located in the stack is extracted from the high temperature side and the low temperature side. The cell is preferably located in the central part of the stack. By doing so, the influence of the variation in the temperature in the pack on the determination of whether or not to reuse is reduced, and the remaining usable period can be calculated with high accuracy.

  Step S2 is a resistance determination step in which the resistance determination unit 23 causes the estimation unit 41 of the cell determination unit 40 to determine whether or not to reuse the target battery based on the determination, and is a second determination step of the reuse technique determination method. .

  The resistance determination unit 23 determines whether or not the measured resistance value belongs to the latent resistance range. The latent resistance range is as described above. The resistance determination unit 23 receives the measured resistance value from the resistance value acquisition unit and the latent resistance range from the latent resistance range storage unit 22.

  If the measured resistance value is outside the range of the potential resistance range (step S2: N), as shown in step S3, the resistance determination unit 23 determines that the test cell can determine whether the reuse is appropriate or not based on the resistance. The result is sent to a display unit (not shown). Then, the suitability of reuse by resistance is determined for the test cell.

  At the time of reuse after determining the suitability of reuse by resistance, if there is a record of the remaining usable period in the previously performed reuse processing, it is preferable to retain this. As a result, the remaining usable period can be effectively utilized. Further, it is preferable to record the date and time of the current collection or determination and the measured resistance value so that they can be referred to when determining the suitability for the next reuse. By referring to these, when re-determination becomes necessary within a short period of time, it can be referred to as a reference value.

  If the measured resistance value is within the potential resistance range (step S2: Y), the resistance determination unit 23 further sends a redetermination command to the estimation unit 41 of the cell determination unit 40. In addition, the determination result is sent to a display unit (not shown) to prompt the user to sample the positive electrode body of the test cell, which is necessary for determining whether or not the cell can be reused based on the LiF coating amount. Accordingly, the process proceeds to step S4.

  Step S4 is a coating value acquisition step in which the coating value acquisition unit 11 acquires the measured coating value of the test cell, that is, the first measurement value, and is the first acquisition step of the reuse technique determination method. The coating value acquisition unit 11 receives the measured coating value from a coating measuring device or the like, and sends the measured coating value to the estimation unit 41. The coating value acquisition unit 11 acquires the measured coating value of the determined test cell that needs to be determined as to whether or not to reuse the LiF coating amount.

An example of a method for selecting a test cell, that is, a sampling method is shown below. In measuring the coating value, the cell is disassembled and a part of the positive electrode body in the cell is sampled. Sampling is preferably performed at about three locations in the cell.
For example, in the case of a wound electrode body, it is preferable to sample at three locations of the re-inner circumference, the central portion, and the re-perimeter. By doing so, the influence of the variation in deterioration within the cell on the determination of whether or not to reuse is reduced, and the remaining usable period can be calculated accurately. The average value of the LiF coating amount measured from each sampling location is obtained as the measured coating value.

  During sampling, a part of the electrode body may be cut out and used for measurement, or may be used for measurement without being cut out. Next, the LiF coating amount is measured. As a method for measuring the amount of LiF coating, for example, LiF in the positive electrode may be extracted with a polar solvent such as acetonitrile and measured by quantitative analysis using an ion chromatograph. The method for measuring the LiF coating amount is not particularly limited.

  Step S5 is a cell determination step in which the estimation unit 41 and the auxiliary determination unit 42 of the cell determination unit 40 cooperate to determine whether or not to reuse the target cell based on the measured coating value and the coating range. It is the 1st determination process of the method determination method. The coating range is as described above. Details of the cell determination step will be described later.

  Step S6 is a step showing branching based on the determination result of step S5. When the auxiliary determination unit 42 determines that the target cell is suitable for reuse (step S6: Y), as shown in step S7, these other cells are used for reuse. At this time, the auxiliary determination unit 42 sends a determination result to a display unit (not shown) to prompt the user to reuse these other cells.

  On the other hand, when it is determined that the target cell is not suitable for reuse (step S6: N), as shown in step S8, these other cells are used for recycling. At this time, the auxiliary determination unit 42 sends the determination result to a display unit (not shown) to prompt the user to recycle the test cell and the target cell.

  Next, details of the cell determination process in step S5 will be described with reference to FIG. Step S11 is a temperature value acquisition step in which the temperature value acquisition unit 12 acquires the measured temperature value of the test cell, and is a third acquisition step of the reuse technique determination method. The measured temperature value is as described above. The temperature value acquisition unit 12 receives the measured temperature value from a temperature measurement device or the like, and sends the measured temperature value to the estimation unit 41. Next, the process proceeds to step S2.

  In step S12, the estimation unit 41 receives the re-determination command, the measured film value, the film range, the LiF transition data, the measured temperature value, and the LiF generation rate data described above, and based on these information, the remaining use of the test battery This is an estimation process for estimating a possible schedule. In FIG. 7, the remaining usable period of the test cell is taken as the usable schedule.

As shown in FIG. 5, the remaining usable period is the difference between the LiF coating amount at the time of recovery, that is, the difference between the measured coating value and the threshold (coating range) of the LiF coating amount obtained in advance, based on the production rate of the lithium fluoride coating It is obtained by squaring the divided value. In FIG. 5, the usable period is represented as the usable years.
The production rate of the LiF film can be calculated by using an Arrhenius plot or the like from the battery use environment temperature, that is, the measured temperature value, and the correlation data of the temperature versus velocity obtained in advance, ie, the LiF production rate data.

  Step S13 is an auxiliary determination step in which the auxiliary determination unit 42 determines whether or not the target cell can be reused based on the remaining usable period. When the remaining usable period is included in the usable period range obtained in advance (step S13: Y), the auxiliary determination unit 42 determines that the test cell is suitable for reuse (step S14).

If the remaining usable period is not included in the usable period range obtained in advance (step S13: N), the auxiliary determination unit 42 determines that the target cell is not suitable for reuse (step S15). The usable period range can be set to be equal to or greater than a predetermined threshold obtained from experiments or experience from the viewpoint of ensuring safety after cell reuse.
In step S16, the determination process in step S5 ends, and the process proceeds to step S6 described above.

<Modification of Embodiment>
FIG. 8 shows a modified example of the non-aqueous electrolyte secondary battery reuse system according to the embodiment. The reuse system 100 includes a storage unit 120 and a processing unit 150. The processing unit 150 includes an acquisition unit 110, a determination unit 130, and an estimation unit 140. Outside the reuse system, a communication network 190 connected thereto is arranged. The communication network 190 is connected to various measuring devices.

The acquisition unit 110 functions as the above-described film value acquisition unit 11, resistance value acquisition unit 21, and temperature value acquisition unit 12. The acquisition unit 110 acquires the measurement film value from the film measurement unit 111, the measurement resistance value from the resistance measurement unit 112, and the measurement temperature value from the temperature measurement unit 113 via the communication network 190.
The acquisition unit 110 sends the measured film value and the measured temperature value to the estimation unit 140 and sends the measured resistance value to the determination unit 130.

  The storage unit 120 functions as the above-described film range storage unit 31, latent resistance range storage unit 22, film pair schedule data storage unit 32, and temperature versus speed data storage unit 33. The storage unit 120 sends the potential resistance range in response to the request of the determination unit 130. In addition, the storage unit 120 sends the coating range, LiF transition data, and LiF generation rate data in response to the request of the estimation unit 140. The storage unit is preferably constituted by a nonvolatile storage means.

  The determination unit 130 functions as the auxiliary determination unit 42 and the resistance determination unit 23 of the cell determination unit 40 described above. The determination unit 130 receives the measured resistance value from the acquisition unit 110 and the remaining usable schedule from the estimation unit 140. The determination unit 130 may receive information on a predetermined range of the remaining usable schedule from a storage unit (not shown).

  The determination unit 130 sends an estimation command to the estimation unit 150 when the measured resistance value belongs to the latent resistance range obtained in advance. The estimation instruction is the same instruction as the above-described re-determination instruction. Although not shown, the determination unit 130 sends the determination result to the terminal device via the communication network 190 and transmits the determination result to the user.

The estimation unit 150 functions as the estimation unit 41 described above. The estimation unit 150 receives the measurement film value and the measurement temperature value sent from the acquisition unit 110. Further, the estimation unit 150 requests the storage unit 120 to transmit the film range, LiF transition data, and LiF generation rate data, and receives them. Further, the estimation unit 150 receives the estimation command sent from the determination unit 130.
The estimation unit 150 sends the remaining available schedule to the determination unit 130.

  The processing unit 150 may include a central processing unit that executes various processes of the acquisition unit 110, the determination unit 130, and the estimation unit 150 based on a control program, and a volatile storage unit. The control program may be sequentially called from the storage unit 120 when the determination process is performed, or may be acquired from a server (not shown) via the communication network 190. The storage unit 120 may acquire the control program from a recording medium (not shown).

Note that the present invention is not limited to the above-described embodiment or its modifications, and can be appropriately changed without departing from the spirit of the present invention.
The reuse system of the nonaqueous electrolyte secondary battery may omit other elements as long as it includes a film value acquisition unit, a film range storage unit, and a cell determination unit. The non-aqueous electrolyte secondary battery reuse technique determination method may omit other elements as long as it includes a film value acquisition step and a cell determination step.

  In the present embodiment, any means may be used as the obtaining unit as long as it is a means or apparatus for obtaining specific information. The specific information includes a value such as a measured value of the amount of film formed, a measured value of the electrical resistance of the battery to be tested, and an average value of the battery operating environment temperature. In the present embodiment, the obtaining operation may include receiving and capturing a value measured mainly by another measuring device or the like. The storage unit can transmit or receive information by wire or wireless.

  Each acquisition unit may also include receiving and capturing a value measured by the reuse system itself if it has a measurement unit. Each acquisition unit may receive a value input by a user from an input unit of the system, may receive a value from a measurement device by wired or wireless, and indirectly from these via a communication network by wired or wireless. May be received automatically.

  Further, any information obtained by nondestructive measurement for a battery may be received from a measurement module provided in the battery. Each acquisition unit may not only acquire but also transfer the acquired information to other means or devices not specified in this embodiment. Each acquisition unit may temporarily hold the acquired information for the purpose of transmission.

In the present embodiment, any means may be used as the storage unit as long as it is a means or device for storing specific information. The specific information includes data or values such as a range of the film generation amount, correlation data between the film generation amount and the use schedule, correlation data between the use environment temperature and the film generation rate, and a range of electric resistance of the test battery.
The storing operation includes temporarily or permanently holding information received from another device. Each storage unit may erase information after a certain period of time, or may accumulate information without erasing. The storage unit can transmit or receive information by wire or wireless.

  In the present embodiment, any means may be used for the determination unit as long as it is a means or device for determining the suitability of battery reuse from specific information. The specific information includes information acquired by the acquisition unit and transmitted to the determination unit, and information stored by the storage unit and transmitted to the determination unit. The determination unit can transmit or receive information by wire or wireless.

  The determination unit may have an incidental function of transmitting the determination result as new information to a transmission device to a user such as a display device or a terminal device including these. Thus, the above information can be provided to the user of the reuse system. The determination unit may transmit the determination result to the storage unit and hold it.

  In the present embodiment, the information acquired in the acquisition step includes a measurement value of the amount of coating produced, a measurement value of the electrical resistance of the test battery, and an average value of the battery usage environment temperature, but other information is acquired. Further, the accuracy of determination may be improved.

  In the present embodiment, information to be determined in the determination step includes information acquired by the acquisition step and information downloaded and used from a specific storage unit as appropriate, but based on other information The accuracy of the determination may be improved. The determination result obtained by the determination step may be transmitted as new information to a transmission device to the user such as a display device or a terminal device including these, and provided to the user of the reuse system. The determination result may be stored in the storage unit.

In the embodiment, the measured value of the electric resistance of one battery in the battery assembly, that is, the test cell, is obtained and used for determination as the measured resistance value. However, the battery assembly or one battery assembly in the battery assembly, ie, the pack, is used. A measurement value obtained by measuring the electrical resistance of the stack with respect to may be obtained and used for determination.
In the embodiment, the LiF film amount was measured for the test cell whose electrical resistance was measured. However, the LiF film amount was measured in another cell belonging to the battery assembly to which the test cell belongs. You may go.

  In addition, the temperature value acquisition unit receives the time transition data of the operating environment temperature instead of the measurement temperature value and sends it to the estimation unit. The estimation unit obtains the measurement temperature value from the time transition data and based on this The remaining usable period may be estimated.

  In the present embodiment, the elapsed period from the start of use of the nonaqueous electrolyte secondary battery, which is obtained in advance as the use schedule, is used. Further, the remaining usable period of the test cell was used as the remaining usable schedule. The schedule relating to the use schedule and the remaining usable schedule may include the following.

The schedule may be the number of uses. The number of times of use may include a cumulative charge amount or a cumulative discharge amount. Further, the schedule may be a cumulative usage time including a cumulative discharge time, a cumulative charge time, a cumulative charge time, and a cumulative charge time. The charge rate and discharge rate may be taken into account for the cumulative usage time.
Further, the number of times of use of the automobile or the like mounted on the battery to be examined, the cumulative usage time, and the elapsed period after the start of use may be used. A cumulative charge amount or a cumulative discharge amount may be added to the elapsed period and the usable period.

  In the embodiment, the auxiliary determination unit determines whether or not the cell can be reused based on the remaining usable schedule calculated by the estimation unit, but whether or not the measured coverage value is included in the coverage range obtained in advance. On the basis of this, the suitability of reuse of other cells belonging to the battery assembly to which the test cell belongs may be determined. In this case, the estimation unit may be omitted.

In this embodiment, the reuse system exists separately from the reproduction use means or the resource recycling means. However, the reuse system is automatically reproduced after determination by being incorporated in these means or coupled via a communication network. Use or recycling may be performed.
In addition, although the recycling and recycling steps are performed separately by the user, they may be performed continuously by the above means.

  In this embodiment, it is assumed that the battery determined to be unsuitable for recycling or reuse is assumed to be recycled. However, if recycling is inappropriate from the viewpoint of efficient use of resources, the battery is discarded. You may make the judgment which should be processed appropriately as a thing.

An embodiment of the present invention will be described with reference to FIGS. An Example demonstrates centering on the part of the estimation process of the remaining implementation possible period in Embodiment.
FIG. 9 is a measurement result of the time transition of the electrical resistance of the cell according to LiF conversion data to be obtained in advance. The resistance value (mΩ) of the IV resistance of the cell was obtained as transition data regarding the square root of the number of days elapsed from the start of use. The battery was used at 75 ° C. so that the increase in electrical resistance started from the first day of use. Thus, even a method of promoting battery deterioration at a high temperature can simulate an increase in electrical resistance when used at a room temperature of about 28 ° C.

FIG. 10 shows the measurement results of the time transition of the LiF coating amount according to LiF conversion data to be obtained in advance. The LiF coating amount (μmol / cm ² ) of the cell was obtained as a regression line relating to the square root of the number of days elapsed from the date of battery pack collection. The battery was used at 75 ° C. as in FIG. 9 so that the increase in the LiF coating amount started from the first day of use.

FIG. 11 is a graph of LiF conversion data to be obtained in advance. The relationship between the resistance value (mΩ) of the IV resistance of the cell and the LiF coating amount (μmol / cm ² ) of the cell was derived from the transition data as a regression line. Assuming that the square root of the LiF coating amount is x and the resistance value is y, the following formula 1 is obtained as shown in FIG.

      y = 0.12x + 2.42 (1)

Here, the threshold value of the LiF coating amount is calculated from the allowable range of the resistance value in which the cell can be reused, that is, the resistance threshold value. For example, when the resistance threshold is 1.35 times the initial resistance of 2.49, the resistance threshold is 2.49 × 1.35 = 3.24 (mΩ). From the relational expression (1), the threshold value of the LiF coating amount is (3.24-2.42) /0.12=6.83 (μmol / cm ² ).

FIG. 12 is a graph in which the time average value T of the battery use environment temperature and the LiF production rate v (μmol / cm ² · day) are Arrhenius plotted. Then, the result of the Arrhenius plot is expressed by the following formula 2.

z = −4.5w + 12.1 (2)
w = 1000 / T, z = ln (v)

Since the LiF coating amount at the time of recovery was 3.5 μmol / cm ² and T = 28 ° C., the LiF production rate v was exp {−4.5 * (1000 / (273 + 28))} + 12.1. = 0.058 (μmol / cm ² ). As shown in FIG. 10, since the LiF coating amount and the square root of the elapsed period are represented as a regression line, the square of the value obtained by dividing the difference between the LiF coating amount threshold and the LiF coating amount at the time of recovery by the LiF generation rate v. Accordingly, the remaining usable period was determined to be {6.83-3.5} /0.058} ² /365=8.9 (years).

  As mentioned above, although this invention was demonstrated according to the said embodiment and Example, it is not limited only to the structure of the said embodiment and Example, In the scope of the invention of the claim of a claim of this application It goes without saying that various variations, modifications, and combinations that can be made by those skilled in the art are included.

11 Coating value acquisition unit (first acquisition unit)
12 Temperature value acquisition unit (third acquisition unit)
21 Resistance value acquisition unit (second acquisition unit)
22 Potential resistance range storage unit (second storage unit)
23 Resistance determination unit (second determination unit)
31 Coating range storage unit (first storage unit)
32 Film pair schedule data storage unit (third storage unit)
33 Temperature vs. speed data storage unit (fourth storage unit)
40 cell determination unit (first determination unit)
41 estimation part 42 auxiliary judgment part S1 resistance value acquisition process (2nd acquisition process)
S2 determination step (second determination step)
S4 Film value acquisition process (first acquisition process)
S5 Part of cell determination step (first determination step) S6 Part of cell determination step (first determination step)

Claims (12)

A first acquisition unit for acquiring a first measurement value obtained by measuring a production amount of a lithium fluoride film generated on the positive electrode;
A first storage unit that holds a first range of a lithium fluoride coating that is obtained in advance on the positive electrode,
A first determination unit that determines whether or not to reuse the target battery based on the first measurement value and the first range;
Non-aqueous electrolyte secondary battery reuse system. A second acquisition unit for acquiring a second measurement value obtained by measuring electric resistance;
A second storage unit that holds a second range relating to electrical resistance that is obtained in advance, and if the second measurement value belongs to the second range, the first determination unit determines whether or not the target battery is to be reused. A second determination unit for causing
The reuse system of the non-aqueous electrolyte secondary battery according to claim 1. The production amount is the production amount of a lithium fluoride coating produced on the positive electrode of a test battery that is a non-aqueous electrolyte secondary battery,
The first range is a range related to the amount of lithium fluoride coating produced on the positive electrode of the non-aqueous electrolyte secondary battery, obtained in advance.
The reuse system of the non-aqueous electrolyte secondary battery according to claim 2. The second measurement value is a measurement value obtained by measuring the electric resistance of the test battery,
The second range is a range relating to the electrical resistance of the non-aqueous electrolyte secondary battery obtained in advance.
The reuse system of the non-aqueous electrolyte secondary battery according to claim 3. The first range is:
First correlation data relating to the amount of lithium fluoride coating produced on the positive electrode of the nonaqueous electrolyte secondary battery and the electrical resistance of the nonaqueous electrolyte secondary battery, obtained in advance,
And calculated | required based on the 3rd range regarding the electrical resistance of the nonaqueous electrolyte secondary battery calculated | required previously,
The reuse system of the non-aqueous electrolyte secondary battery according to claim 3 or 4. The first correlation data is a regression line of the generation amount of the lithium fluoride film obtained in advance and the electric resistance of the non-aqueous electrolyte secondary battery obtained in advance.
The reuse system of the nonaqueous electrolyte secondary battery according to claim 5. A third storage unit that holds second correlation data regarding a use schedule of the non-aqueous electrolyte secondary battery and a generation amount of the lithium fluoride film on the positive electrode of the non-aqueous electrolyte secondary battery, which are obtained in advance; ,
The first determination unit is configured to estimate a remaining usable schedule of the test battery based on the first measurement value, the first range, and the second correlation data;
An auxiliary determination unit that determines whether or not the target battery can be reused based on the remaining usable schedule; and
The reuse system of the non-aqueous electrolyte secondary battery according to any one of claims 3 to 6. The use schedule is an elapsed period from the start of use of the non-aqueous electrolyte secondary battery obtained in advance,
The usable schedule is a remaining usable period of the test battery.
The reuse system of the nonaqueous electrolyte secondary battery according to claim 7. A third acquisition unit for acquiring a third measurement value obtained by measuring a use environment temperature of the test battery;
A fourth storage unit that holds third correlation data relating to the use environment temperature of the non-aqueous electrolyte secondary battery obtained in advance and the generation rate of the lithium fluoride coating on the positive electrode of the non-aqueous electrolyte secondary battery; With
The estimation unit further estimates the remaining usable period based on the third measurement value and the third correlation data.
The reuse system of the nonaqueous electrolyte secondary battery according to claim 8.   The reuse system for a nonaqueous electrolyte secondary battery according to any one of claims 3 to 9, wherein the target battery is another battery belonging to a battery assembly to which the test battery belongs. . A first acquisition step of acquiring a first measurement value obtained by measuring the amount of lithium fluoride coating produced on the positive electrode;
A first determination step of determining whether or not to reuse the target battery based on the first measurement value and the first range of the lithium fluoride film generated on the positive electrode determined in advance.
Non-aqueous electrolyte secondary battery reuse method determination method. A second acquisition step of acquiring a second measurement value obtained by measuring electric resistance;
A second determination step of determining whether or not the second measurement value belongs to a second range,
Performing the first determination step on the battery in which the second measurement value belongs to the second range;
The reuse method determination method of the non-aqueous electrolyte secondary battery according to claim 11.

Images