JP6930386B2 - How to handle the secondary battery - Google Patents

Description

The present invention relates to a method for processing a secondary battery.

An assembled battery including a plurality of secondary batteries is used as a power source for running a vehicle, for example, and an old one is replaced. However, some of the collected old assembled batteries are equipped with a secondary battery having good battery characteristics, and if such a secondary battery can be separated from the assembled battery, the secondary battery can be reused efficiently. can do.

On the other hand, as the secondary battery deteriorates, gas is generated inside and the internal pressure becomes high, so that the secondary battery may be deformed such as expansion. Therefore, the secondary battery used for the assembled battery may be arranged so that the deformation in the arrangement direction is restricted. In such an assembled battery, it cannot be determined from the appearance whether or not the 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 being separated from the assembled battery and become unusable.

Patent Document 1 discloses a method for inspecting a secondary battery when reusing an assembled battery in which secondary batteries are arranged so that deformation in at least the arrangement direction is restricted. In the method for inspecting a secondary battery according to Patent Document 1, it is determined that each secondary battery can be separated when the load applied to prevent the deformation of the secondary battery is equal to or less than the threshold value, and the deformation of the secondary battery is prevented. If the load applied to the battery exceeds the threshold value, it is judged that the respective secondary batteries should not be separated.

Japanese Unexamined Patent Publication No. 2016-1331076

In the method for inspecting a secondary battery according to Patent Document 1, since it is determined that the assembled battery including the secondary battery having a high internal pressure should not be separated, the assembled battery including the secondary battery having a high internal pressure is separated and reused. There was a problem that it could not be done.

The present invention has been made in view of such circumstances, and provides a method for processing a secondary battery capable of separating and reusing an assembled battery including a secondary battery having a high internal pressure.

The method for treating a secondary battery according to the present invention is a method for treating a secondary battery for reusing an assembled battery in which a plurality of secondary batteries are arranged and deformation of the secondary battery is restricted with respect to at least the arrangement direction. The characteristic value determination step for determining whether or not the battery characteristic value of the secondary battery is within a predetermined range, and the internal pressure of the secondary battery in a state where the deformation of the secondary battery is restricted. The secondary battery in which the internal pressure release step and the characteristic value determination step determine that the battery characteristic value is within a predetermined range and the internal pressure is released in the internal pressure release step is described. It is characterized by including a separation step for taking out from the assembled battery.

In the method for processing a secondary battery according to the present invention, a secondary battery having good battery characteristics is taken out from the assembled battery after releasing the internal pressure in a state where deformation is restricted. That is, for an assembled battery including a secondary battery having a reusable battery characteristic but a high internal pressure, the internal pressure of the corresponding secondary battery is released and then separated. Therefore, it is possible to prevent the secondary battery from expanding and becoming unusable after being separated from the assembled battery.
In this way, in the method for processing a secondary battery according to the present invention, the assembled battery including the secondary battery having a high internal pressure can be separated and reused.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a method for processing a secondary battery in which a secondary battery having a high internal pressure can be separated from the assembled battery and reused.

It is a top view of the assembled battery which concerns on this embodiment. It is a front view of the assembled battery which concerns on this embodiment. It is a perspective view of the secondary battery which concerns on this embodiment. It is a flow chart of the processing method of the secondary battery which concerns on this embodiment. In this embodiment, it is a figure which shows the example of measuring the load applied to the whole row of secondary batteries. In this embodiment, it is a graph which shows the relationship between the battery characteristic of the secondary battery after the internal pressure is released and the dew point of the external space when the internal pressure is released. It is a flow chart in the case which includes the step of measuring the battery characteristic value of the whole assembled 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. In addition, the following description and drawings have been simplified as appropriate to clarify the description.

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

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 arranged alternately between the two end plates 30 located at both ends while being in contact with each other.
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 a cooling fluid such as air to flow.

Further, as shown in FIG. 2, a restraint 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 via a metal bus bar 50. The bus bar 50 is fastened by a metal nut 60. In this way, all the secondary batteries 10 are electrically connected.

Here, the detailed configuration of the pressure release portion 13 will be described with reference to FIG. FIG. 3 is a perspective view of the secondary battery 10. As shown in FIG. 3, the pressure release portion 13 includes a pressure release hole 131 provided in the upper part of the case of the secondary battery 10, an O-ring 132, and a bolt 133.

The pressure opening hole 131 is a hole that communicates the external space and the internal space of the secondary battery 10, 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 hermetically sealed.
When the secondary battery 10 is continuously used, gas is accumulated in the case of the secondary battery 10 as it deteriorates, and the internal space of the secondary battery 10 becomes a positive pressure state. When the bolt 133 is loosened in this state, the gas in the case is discharged from the pressure opening hole 131 to the external space, and the internal pressure of the secondary battery 10 is released. If the bolt 133 is re-tightened after the internal pressure of the secondary battery 10 is released, the secondary battery 10 can be used again.

Next, the processing method of the secondary battery according to the present embodiment will be described with reference to the flow chart of FIG. The method for processing the secondary battery according to the present embodiment is a processing method for reusing each of the secondary batteries 10 with respect to the recovered used assembled battery 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, the battery capacity value and the internal resistance value are measured as the battery characteristic values.

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 the full electric capacity, the secondary battery 10 is completely discharged at a constant current value. The time-integrated value of the current discharged at this time can be measured as the battery capacity value of the secondary battery 10.

Further, 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 1C for 10 seconds in a constant temperature environment of 25 ° C., and the battery voltage value at the end of the discharge is set. The measurement is performed, and the secondary battery 10 is charged again until the amount of electricity before discharging is reached. This charge / discharge cycle is repeated while changing the current values to 3C, 5C, and 10C, and the battery voltage value at the end of discharge is measured according to each discharge current value. After that, 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 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 for each of the secondary batteries 10 constituting the assembled battery 1, the battery characteristic value measured in step S10 (characteristic value measurement step). However, it is determined whether or not it is within the predetermined allowable range.
If at least one of the secondary batteries 10 included in the assembled battery 1 has a battery characteristic value within the permissible range, it is determined that there is a secondary battery 10 that can be separated and reused, and step S30 (internal pressure measurement). Step). On the other hand, if all the secondary batteries 10 included in the assembled battery 1 are out of the permissible range, it is determined that there is no reusable secondary battery 10, and the process proceeds to step S65 (disposal step). If the process proceeds to step S65, the assembled battery 1 is discarded and the process ends.

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

First, the measuring plate 70 of the load measuring device is brought into contact with the outer surface of the end plate 30 of the assembled battery 1 without a gap and fixed. When all the restraint bands 40 of the assembled battery 1 are removed with the measuring plate 70 fixed, the reaction force of the load applied to the entire row of the secondary batteries 10 is applied to the inner surface of the measuring plate 70. Since the load measuring device is configured to be able to measure the load that presses the inner side surface of the measuring plate 70 outward, it is possible to measure the reaction force of the compressed load in the assembled battery 1. 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 batteries 10 is equal to or less than a predetermined threshold value. If the load applied to the entire row of the secondary batteries 10 exceeds the threshold value, the internal pressure of the secondary batteries 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 batteries 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 deformation such as expansion does not occur even if the secondary batteries 10 are separated, and step S60. 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 where the deformation of the secondary battery 10 is restricted. Specifically, as shown in FIG. 5, in a state where the measurement plate 70 is 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 substantially equal to the external air pressure, the bolt 133 of the secondary battery 10 is fastened again, and the process proceeds to step S60 (separation step).

In step S60 (separation step), the secondary battery 10 to be separated and reused is separated from the assembled battery 1, and the process is completed. The separated secondary battery 10 may be reused in a single form, or may be reused by forming a new assembled battery with another secondary battery 10.
When forming a new assembled battery by combining a plurality of the collected secondary batteries 10, it is advisable to combine them so that only a part of the secondary batteries 10 is not biased and deteriorated. For example, depending on the usage environment, among the secondary batteries included in the assembled battery, the outer one may deteriorate faster than the central one. In such a case, if the assembled battery is formed by arranging the secondary battery 10 having a good battery characteristic value on the outside and arranging the secondary battery 10 having a relatively low battery characteristic value on the inside, it deteriorates. However, the performance difference between the secondary batteries 10 is unlikely to occur, and the battery can be used for a long time.

The environment of the external space when the internal pressure is released in step S50 (internal pressure release step) of the above 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 the internal pressure is released and the dew point of the external space when the internal pressure is released.

The vertical axis of FIG. 6 shows the battery capacity after the battery capacity of the secondary battery 10 immediately after the internal pressure is released is set to 100% and the cycle of full charge and complete discharge is performed 200 times from there. It can be said that the higher the value on the vertical axis, the better the battery characteristics of the secondary battery 10. The horizontal axis of FIG. 6 indicates the dew point of the external space when the internal pressure is released.

As shown in FIG. 6, it can be seen that the lower the dew point of the external space when the internal pressure is released, the better the battery characteristics of the secondary battery 10. That is, it can be said that the dew point of the external space when the internal pressure is released is preferably 0 ° C. or lower, more preferably −30 ° C. or lower, and even more preferably −60 ° C. or lower.
This is because the water vapor pressure is low, especially in a dew point environment of 0 ° C. or lower, so that when the bolt 133 of the secondary battery 10 is loosened, the amount of water vapor flowing into the inside of the secondary battery 10 from the external space is reduced, and this is due to the water vapor. It is considered that this is because the decomposition of the electrolytic solution and the corrosion of the electrodes were suppressed.

Further, even if the internal pressure of the secondary battery 10 is released in the atmosphere of dry air or an inert gas, it is possible to suppress the inflow of water vapor into the secondary battery 10. 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 for processing the secondary battery according to the present embodiment, the secondary battery 10 having reusable battery characteristics and high internal pressure is separated after the internal pressure of the secondary battery 10 is released. do. Therefore, the expansion of the secondary battery 10 after separation can be suppressed and can be reused.

The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the spirit.

For example, in the above embodiment, the battery characteristic values of the individual secondary batteries 10 were first measured in step S10, but as another embodiment, as shown in FIG. 7, step S01 ( The assembled battery characteristic measurement step) and step S02 (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 assembled battery 1.
After that, in step S02 (assembling battery characteristic determination step), if the battery characteristic value of the assembled battery 1 is within a predetermined allowable range, the process proceeds to step S10 (characteristic value measuring step), and the entire assembled battery 1 is performed. If the battery characteristic value is out of the predetermined allowable range, the process proceeds to step S65 (disposal step).

When step S01 and step S02 are provided in this way, the assembled battery 1 to be discarded can be selected without inspecting the battery characteristic values of the secondary batteries 10 included in the assembled battery 1 one by one. Therefore, the efficiency for measuring the battery characteristic value can be increased.

Further, in the above embodiment, the processing method of the secondary battery including step S30 (load measurement step) and step S40 (load determination step) has been described, but in other embodiments, these may be omitted. .. That is, after determining the battery characteristic value of the secondary battery 10 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. You may.

When steps S30 and S40 are omitted in this way, the method for processing the secondary battery according to the present invention can be applied even when there is no load measuring device.
Further, the present invention also applies to an assembled battery in which it is structurally difficult to measure the internal pressure of the secondary battery, such as an assembled battery in which a secondary battery is incorporated one by one in a plurality of fixed frames. The processing method of the secondary battery can be applied.

Further, in the above embodiment, a method of first measuring the battery characteristic value of the secondary battery 10 and then releasing the internal pressure of the secondary battery 10 whose battery characteristic value is within the permissible range has been described. In this case, the operation of releasing the internal pressure of the secondary battery 10 can be suppressed to the minimum number of times.
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 the internal pressure of the secondary battery 10 is released, the secondary battery 10 can be handled in a safe state.

As described above, in the method for treating a secondary battery according to the present invention, an assembled battery including a secondary battery having a high internal pressure can be separated and reused.

1 set battery 10 secondary battery 11 positive electrode terminal 12 negative electrode terminal 13 pressure release 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)

A method for processing a secondary battery for reusing an assembled battery in which a plurality of secondary batteries are arranged and at least the deformation of the secondary battery is restricted with respect to the arrangement direction.
A characteristic value determination step for determining whether or not the battery characteristic value of the secondary battery is within a predetermined range, and a characteristic value determination step.
An internal pressure release step of releasing the internal pressure of the secondary battery in a state where the deformation of the secondary battery is restricted, and
A separation step in which the secondary battery, which is determined to be within a predetermined range in the characteristic value determination step and whose internal pressure is released in the internal pressure release step, is taken out from the assembled battery. With,
How to handle the secondary battery.

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