JP2019087485A - Secondary battery disposal method - Google Patents

Abstract

To provide a secondary battery disposal method that can separate a battery pack including secondary batteries with high internal pressure and reuse it.SOLUTION: A secondary battery disposal method according to the present invention is a secondary battery disposal method for reusing a battery pack 1 in which a plurality of secondary batteries 10 are disposed and deformation of the secondary batteries 10 is regulated at least with respect to an arrangement direction. The method includes: a characteristic value determination step S10 for determining whether each of battery characteristic values of the secondary batteries 10 is within a predetermined range; an internal pressure releasing step S50 for releasing internal pressure of the secondary batteries 10 in a state in which deformation of the secondary batteries 10 is regulated; and a separation step S60 of taking out, from the battery pack 1, the secondary batteries 10 about which it is determined that the battery characteristic value is within the predetermined range in the characteristic value determination step S10 and the internal pressure is released in the internal pressure releasing step S50.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method of treating a secondary battery.

  An assembled battery including a plurality of secondary batteries is used, for example, as a power source for driving a vehicle, and old ones are replaced. However, some of the recovered old assembled batteries also have a secondary battery with good battery characteristics, and if such a secondary battery can be separated from the assembled battery, the secondary battery can be efficiently reused. can do.

  On the other hand, since the secondary battery generates gas inside with the deterioration and the internal pressure becomes high, deformation such as expansion may occur. Therefore, the secondary batteries used in the assembled battery may be arranged such that deformation in the arrangement direction is restricted. In such a battery pack, it can not be judged from the appearance whether a secondary battery to be separated and reused has a high internal pressure. Therefore, the secondary battery, which was reusable in the state of the assembled battery, may expand due to separation from the assembled battery, and may become unusable.

  Patent Document 1 discloses a method of inspecting a secondary battery when reusing the assembled battery in which the secondary battery is arranged such that deformation at least in the arrangement direction is regulated. In the inspection method of the secondary battery according to Patent Document 1, it is judged that each secondary battery can be separated if the applied weight is equal to or less than the threshold in order to prevent the deformation of the secondary battery, and the deformation of the secondary battery is prevented. It is determined that each secondary battery should not be separated if the weight applied for the purpose exceeds the threshold.

JP, 2016-131076, A

  In the inspection method of the secondary battery according to Patent Document 1, it is judged that the assembled battery including the secondary battery having a high internal pressure can not be separated, so the assembled battery including the secondary battery having a high internal pressure is separated and reused There was a problem that I could not do it.

  The present invention has been made in view of such circumstances, and provides a method of treating a secondary battery that can separate and reuse an assembled battery including a secondary battery with a high internal pressure.

  A method of treating a secondary battery according to the present invention is a method of treating a secondary battery, in which a plurality of secondary batteries are arranged, and at least a battery pack in which deformation of the secondary battery in the arrangement direction is restricted is reused. A characteristic value determining step of determining whether or not the battery characteristic value of the secondary battery is within a predetermined range; and an internal pressure of the secondary battery in a state in which the deformation of the secondary battery is regulated The secondary battery in which the battery characteristic value is determined to be within a predetermined range in the internal pressure releasing step of releasing the internal pressure and the characteristic value determining step, and the internal pressure is released in the internal pressure releasing step is And a separation step of taking out from the assembled battery.

In the method of treating a secondary battery according to the present invention, the secondary battery having good battery characteristics is taken out from the assembled battery after releasing the internal pressure in a state in which deformation is regulated. That is, with respect to the assembled battery including the secondary battery having a high internal pressure while having reusable battery characteristics, the internal pressure of the corresponding secondary battery is released and then separated. Therefore, the secondary battery can be prevented from expanding and becoming unusable after being separated from the assembled battery.
Thus, in the method of treating a secondary battery according to the present invention, a battery pack including a secondary battery with a high internal pressure can be separated and reused.

  According to the present invention, it is possible to provide a method of treating a secondary battery capable of separating and reusing the secondary battery having a high internal pressure from the assembled battery.

It is a top view of the assembled battery concerning this embodiment. It is a front view of the assembled battery concerning this embodiment. It is a perspective view of the secondary battery concerning this embodiment. It is a flowchart of the processing method of the secondary battery which concerns on this embodiment. In this embodiment, it is a figure which shows the example which measures the load concerning the whole row | line | column of a secondary battery. In this embodiment, it is a graph which shows the relationship between the battery characteristic of the secondary battery after internal pressure releasing, and the dew point of the external space at the time of internal pressure releasing. It is a flowchart in the case of including the step which measures the battery characteristic value of the whole group battery.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Further, in order to clarify the explanation, the following description and the drawings are simplified as appropriate.

First, the configuration of the battery assembly 1 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a top view of the battery assembly 1, and FIG. 2 is a front view of the battery assembly 1.
As shown in FIG. 1, the assembled battery 1 includes a secondary battery 10, a spacer 20, an end plate 30, a restraining band 40, a bus bar 50, and a nut 60. In addition, the secondary battery 10 includes a positive electrode terminal 11, a negative electrode terminal 12, and a pressure release portion 13.
The battery assembly 1 is, for example, a battery assembly used as a power supply for driving an automobile, and is usually covered with an insulating cover such as plastic during use.

The secondary battery 10, the spacer 20, and the end plate 30 all have a rectangular flat plate shape. As shown in FIG. 1, a plurality of secondary batteries 10 and spacers 20 are alternately arranged in contact with each other between two end plates 30 positioned at both ends.
The spacer 20 is a plate having an insulating property, and secures insulation between the secondary batteries 10. The spacer 20 may have a structure provided with a flow path for flowing a cooling fluid such as air.

  Further, as shown in FIG. 2, a restraining band 40 is attached so as to sandwich and connect the end plate 30. With such a configuration, the secondary battery 10, the spacer 20, and the end plate 30 are fixed, and deformation such as expansion of the secondary battery 10 is restricted at least in the arrangement direction.

  Further, as shown in FIG. 1, the positive electrode terminals 11 of the arranged secondary batteries 10 are electrically connected to the negative electrode terminals 12 of the adjacent secondary battery 10 through the metal bus bars 50. The bus bar 50 is fastened by a metal nut 60. Thus, all the secondary batteries 10 are electrically connected.

  Here, the detailed structure of the pressure release part 13 is demonstrated using FIG. FIG. 3 is a perspective view of the secondary battery 10. As shown in FIG. 3, the pressure release unit 13 includes a pressure release hole 131 provided in the upper portion of the case of the secondary battery 10, an O-ring 132, and a bolt 133.

The pressure release hole 131 is a hole communicating the external space of the secondary battery 10 with the internal space, and when the secondary battery 10 is used, the bolt 133 is usually fastened via the O-ring 132. It is blocked. That is, the secondary battery 10 is sealed.
When the use of the secondary battery 10 is continued, gas is accumulated in the case of the secondary battery 10 as it is deteriorated, and the internal space of the secondary battery 10 becomes in a positive pressure state. In this state, when the bolt 133 is loosened, the gas in the case is discharged from the pressure release hole 131 to the external space, and the internal pressure of the secondary battery 10 is released. If the internal pressure of the secondary battery 10 is released and the bolt 133 is tightened, the secondary battery 10 can be used again.

  Next, the processing method of the secondary battery according to the present embodiment will be described using the flowchart of FIG. 4. The processing method of the secondary battery according to the present embodiment is a processing method for reusing each secondary battery 10 with respect to the collected used battery pack 1.

  First, in step S10 (characteristic value measurement step), the battery characteristic values of the individual secondary batteries 10 constituting the assembled battery 1 are measured. In the present embodiment, a battery capacity value and an internal resistance value are measured as the battery characteristic value.

  The battery capacity value of the secondary battery 10 can be measured by a known method. Specifically, for example, after charging the secondary battery 10 to full capacity, it is completely discharged at a constant current value. The time integration value of the current discharged at this time can be measured as the battery capacity value of the secondary battery 10.

  In addition, the internal resistance value of the secondary battery 10 can also be measured by a known method. Specifically, for example, the secondary battery 10 charged to a certain amount of electricity is discharged at a constant current value of 1 C for 10 seconds in a constant temperature environment of 25 ° C., and the battery voltage value at the end of the discharge is The secondary battery 10 is measured and charged again to the amount of electricity before discharging. This charge and discharge cycle is repeated while changing the current value to 3 C, 5 C, and 10 C, and the battery voltage value at the end of the discharge is measured according to each discharge current value. Thereafter, the data obtained by the above discharge is plotted on a coordinate plane in which the horizontal axis is the discharge current value and the vertical axis is the battery voltage value at the end of the discharge. Then, based on these plot data, an approximate straight line can be calculated by the least squares method, and the slope thereof can be obtained as the internal resistance value of the secondary battery 10.

Next, as shown in FIG. 4, the process proceeds to step S20 (characteristic value determination step), and the battery characteristic value measured in step S10 (characteristic value measurement step) for each of the secondary batteries 10 constituting the assembled battery 1 Is determined to be within a predetermined tolerance.
If at least one of the secondary batteries 10 included in the assembled battery 1 has a battery characteristic value within the allowable range, it is determined that there is a secondary battery 10 that can be separated and reused, and step S30 (internal pressure measurement Go to step). On the other hand, when all the secondary batteries 10 included in the assembled battery 1 are out of the allowable range, it is determined that there is no reusable secondary battery 10, and the process proceeds to step S65 (discarding step). If the process proceeds to step S65, the battery pack 1 is discarded and the process is ended.

  In step S30 (load measurement step), the load in the column direction applied to the entire row of the secondary batteries 10 included in the battery assembly 1 is measured. The load applied to the entire row of secondary batteries 10 can be measured by a known load measuring device. FIG. 5 shows a state in which a load applied to the entire row of secondary batteries 10 is measured by a known load measuring device. The load measuring device shown in the example of FIG. 5 comprises two measuring plates 70.

  First, the measuring plate 70 of the load measuring device is brought into contact with and fixed to the outer surface of the end plate 30 of the battery assembly 1 without a gap. When all the restraint bands 40 of the battery assembly 1 are removed with the measurement plate 70 fixed, the reaction force of the load applied to the entire row of the secondary batteries 10 is applied to the inner side of the measurement plate 70. The load measuring device is configured to be able to measure the load that presses the inner side surface of the measurement plate 70 outward, so that the reaction force of the compressive load in the battery assembly 1 can be measured. By regarding this measured value as the load applied to the entire row of the secondary batteries 10, the load applied to the entire row of the secondary batteries 10 can be measured.

  Next, as shown in FIG. 4, the process proceeds to step S40 (load determination step), and it is determined whether or not the load applied to the entire row of the secondary battery 10 is equal to or less than a predetermined threshold. If the load applied to the entire row of the secondary battery 10 exceeds the threshold value, the internal pressure of the secondary battery 10 to be separated and reused may be high, so the process proceeds to step S50 (internal pressure release step). On the other hand, when the load applied to the entire row of the secondary battery 10 is equal to or less than the threshold value, it is determined that the internal pressure of each secondary battery 10 is sufficiently low and that no separation such as expansion occurs even if separated; Proceed to (Separation step).

  In step S50 (internal pressure release step), the internal pressure of the secondary battery 10 to be separated and reused is released in a state in which the deformation of the secondary battery 10 is restricted. Specifically, as shown in FIG. 5, with the measurement plate 70 fixed to the outer surface of the end plate 30 of the assembled battery 1, the bolt 133 of the secondary battery 10 to be separated and reused is loosened. By doing so, the internal pressure of the secondary battery 10 can be released while maintaining the shape of the secondary battery 10. After discharging the gas in the secondary battery 10 until the internal pressure of the secondary battery 10 becomes almost equal to the external pressure, the bolt 133 of the secondary battery 10 is tightened again, and the process proceeds to step S60 (separation step).

In step S60 (separation step), the secondary battery 10 desired to be separated and reused is separated from the assembled battery 1, and the process is ended. The separated secondary battery 10 may be reused in a single form, or may be reused by forming a new battery pack with another secondary battery 10.
In the case where a plurality of collected secondary batteries 10 are combined to form a new assembled battery, it is preferable to combine in consideration that only a part of the secondary batteries 10 do not deteriorate biased. For example, depending on the use environment, there are cases where the outer battery among the secondary batteries included in the assembled battery is deteriorated more quickly than the central battery. In such a case, when the battery pack is formed such that the secondary battery 10 having good battery characteristic values is disposed on the outside and the secondary battery 10 having relatively low battery characteristic values is disposed on the inside, deterioration occurs. Also, the performance difference between the secondary batteries 10 is less likely to occur, and can be made to last longer.

  The environment of the external space when releasing the internal pressure in step S50 (internal pressure releasing step) of the above-described embodiment correlates with the battery characteristics of the secondary battery 10 after the internal pressure is released. FIG. 6 is a graph showing the relationship between the battery characteristics of the secondary battery 10 after internal pressure release and the dew point of the external space at internal pressure release.

  The vertical axis in FIG. 6 shows the battery capacity after the battery capacity of the secondary battery 10 immediately after releasing the internal pressure is 100%, and after 200 cycles of full charge and full discharge from this. It can be said that the battery characteristic of the secondary battery 10 is better as the value on the vertical axis is higher. The horizontal axis in FIG. 6 indicates the dew point of the external space when releasing the internal pressure.

As shown in FIG. 6, it is understood that the battery characteristics of the secondary battery 10 are better as the dew point of the external space is lower when the internal pressure is released. That is, the dew point of the external space at the time of internal pressure release is preferably 0 ° C. or less, more preferably −30 ° C. or less, and still more preferably −60 ° C. or less.
This is because the water vapor pressure is low particularly in a dew point environment of 0 ° C. or less, so when the bolt 133 of the secondary battery 10 is loosened, the amount of water vapor flowing from the external space into the interior of the secondary battery 10 decreases. It is considered that the decomposition of the electrolyte and the corrosion of the electrode were suppressed.

  In addition, even if the internal pressure of the secondary battery 10 is released in an atmosphere of dry air or an inert gas, the flow of water vapor into the secondary battery 10 can be suppressed. Therefore, the operation of releasing the internal pressure of the secondary battery 10 is preferably performed in an atmosphere of dry air or an inert gas.

  As described above, in the method of processing a secondary battery according to the present embodiment, separation is performed after releasing the internal pressure of the secondary battery 10 to the secondary battery 10 having reusable battery characteristics and a high internal pressure. Do. For this reason, expansion of the secondary battery 10 after separation can be suppressed, and can be reused.

  In addition, this invention is not limited to said embodiment, It is possible to change suitably in the range which does not deviate from the meaning.

  For example, in the above embodiment, the battery characteristic value of each secondary battery 10 was first measured in step S10, but as another embodiment, as shown in FIG. 7, step S01 (step S01) An assembled battery characteristic measuring step) and a step S 02 (assembled battery characteristic determination step) may be provided.

In step S01 (assembled battery characteristic measurement step), the battery characteristic value of the entire assembled battery 1 is measured. Specifically, the battery capacity, the internal resistance value, and the like are measured using the external terminal provided in the battery pack 1.
Thereafter, when the battery characteristic value of the assembled battery 1 is within the predetermined allowable range in step S02 (the assembled battery characteristic determining step), the process proceeds to step S10 (the characteristic value measuring step). If the battery characteristic value as D is out of the predetermined allowable range, the process proceeds to step S65 (discarding step).

  As described above, when step S01 and step S02 are provided, the assembled battery 1 to be discarded can be sorted out without checking the battery characteristic values of the secondary battery 10 provided in the assembled battery 1 one by one. Therefore, the efficiency for measuring the battery characteristic value can be increased.

  Moreover, although said embodiment demonstrated the processing method of the secondary battery provided with step S30 (load measurement step) and step S40 (load determination step), these may be abbreviate | omitted in other embodiment. . That is, after the battery characteristic value of the secondary battery 10 is determined in step S20 (characteristic value determination step), the process directly proceeds to step S50 (internal pressure release step) to release the internal pressure of the secondary battery 10 to be separated and reused. May be

Thus, when step S30 and step S40 are omitted, the method of processing a secondary battery according to the present invention can be applied even if there is no load measuring device.
Further, the present invention is also applicable to a battery assembly in which it is difficult to measure the internal pressure of the secondary battery, such as a battery assembly in which the secondary battery is incorporated one by one in a plurality of fixed frames. The method of treating the secondary battery can be applied.

In the above embodiment, the method for measuring the battery characteristic value of the secondary battery 10 and then releasing the internal pressure of the secondary battery 10 within the allowable range was described. In this case, the operation of releasing the internal pressure of the secondary battery 10 can be minimized.
On the other hand, as another embodiment, the internal pressure of the secondary battery 10 may be released first, and then the battery characteristic value of the secondary battery 10 may be measured. In this case, since various operations are performed after releasing the internal pressure of the secondary battery 10, the secondary battery 10 can be handled in a safe state.

  As described above, the method of treating a secondary battery according to the present invention can separate and reuse an assembled battery including a secondary battery having a high internal pressure.

DESCRIPTION OF SYMBOLS 1 assembled battery 10 secondary battery 11 positive electrode terminal 12 negative electrode terminal 13 pressure relief part 20 spacer 30 end plate 40 restraint band 50 bus bar 60 nut 70 measurement plate 131 pressure release hole 132 O ring 133 bolt

Claims (1)

What is claimed is: 1. A method of processing a secondary battery, comprising: arranging a plurality of secondary batteries; and reusing a battery pack in which the deformation of the secondary battery is restricted at least in the arrangement direction,
A characteristic value determining step of determining whether the battery characteristic value of the secondary battery is within a predetermined range;
An internal pressure releasing step of releasing the internal pressure of the secondary battery in a state where the deformation of the secondary battery is regulated;
A separation step in which the battery characteristic value is determined to be within a predetermined range in the characteristic value determination step, and the secondary battery whose internal pressure is released in the internal pressure release step is taken out from the assembled battery; Equipped with
Processing method of secondary battery.

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