Method for manufacturing a power storage module and power storage module

Abstract

To provide a manufacturing method of a power storage module which can secure that an inner pressure of each power storage cell is appropriate, and provide the power storage module.SOLUTION: A manufacturing method of a power storage module 1 comprises: a preparation step of preparing at least one power storage cell 10 each having a liquid injection port 16h; a fixing step of attaching and fixing a sealing member 20 of a liquid injection member; a measurement step of measuring a shape of the sealing member 20; a pressure reduction step of reducing a pressure in the power storage cell 10; a re-measurement step of measuring the shape of the sealing member 20 again after the pressure reduction step; and a determination step of calculating a displacement amount of the sealing member 20 on the basis of a measurement result in the measurement step and a measurement result in the re-measurement step, and determining that an internal pressure of the power storage cell 10 is appropriate when the displacement amount is equal to or greater than a reference value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a power storage module and a power storage module.

Background Art

[0002] For example, Patent Document 1 discloses a method for determining the generation of gas in a case based on the amount of deformation of the case of a secondary battery.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a secondary battery (cell) is used, gas may be generated inside the case of the cell. Therefore, it is required to guarantee the internal pressure of the cell during manufacturing.

[0005] An object of the present disclosure is to provide a method for manufacturing a power storage module and a power storage module capable of guaranteeing that the internal pressure of each power storage cell is appropriate.

Means for Solving the Problems

[0006] A method for manufacturing a power storage module according to an aspect of the present disclosure includes a preparation step of preparing at least one power storage cell including a liquid injection member having a liquid injection port for injecting an electrolytic solution, a fixing step of attaching and fixing the sealing member to the liquid injection member so that the liquid injection port is covered with the sealing member made of a flexible material capable of sealing the liquid injection port, a measuring step of measuring the shape of the sealing member fixed to the liquid injection member, a depressurization step of depressurizing the inside of the power storage cell after the measuring step, a sealing step of sealing the power storage cell after the depressurization step, a re-measuring step of measuring the shape of the sealing member again after the sealing step, a calculating step of calculating a displacement amount of the sealing member based on a measurement result in the measuring step and a measurement result in the re-measuring step, and a determination step of determining that the internal pressure of the power storage cell is appropriate when the displacement amount is equal to or greater than a reference value.

[0007] Further, a power storage module according to an aspect of the present disclosure includes at least one power storage cell each having a liquid injection port for injecting an electrolytic solution, and a sealing member having flexibility and sealing the liquid injection port of the at least one power storage cell. The at least one power storage cell includes a liquid injection member having the liquid injection port. The liquid injection member is formed in an annular shape and has a receiving surface for receiving the sealing member. The sealing member includes an annular contact portion in contact with the receiving surface and an inner portion located inside the annular contact portion. The inner portion is recessed from the annular contact portion, and the internal pressure of the power storage cell is below atmospheric pressure.

Advantages of the Invention

[0008] According to the present disclosure, it is possible to provide a method for manufacturing a power storage module and a power storage module that can ensure that the internal pressure of each power storage cell is appropriate.

Brief Description of the Drawings

[0009]

Figure 1

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Embodiments for Carrying Out the Invention

[0010] Embodiments of the present disclosure will be described with reference to the drawings. In the drawings referred to below, the same or corresponding members are denoted by the same numbers.

[0011] FIG. 1 is a perspective view schematically showing a power storage cell manufactured by the method for manufacturing a power storage module according to an embodiment of the present disclosure. FIG. 2 is a plan view of the power storage module shown in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. This power storage module 1 is mounted on a vehicle, for example.

[0012] As shown in FIGS. 1 to 3, the power storage module 1 of the present embodiment includes a plurality of power storage cells 10 and a sealing member 20.

[0013] A plurality of power storage cells 10 are arranged side by side in one direction (the left - right direction in FIG. 3). In this embodiment, the power storage module 1 includes 30 power storage cells 10 arranged side by side in the one direction. The internal pressure of each power storage cell 10 is maintained at an appropriate value below atmospheric pressure. As shown in FIG. 3, each power storage cell 10 is composed of a bipolar cell. That is, each power storage cell 10 has a current collector member 11, a positive electrode active material layer 12, a negative electrode active material layer 13, a separator 14, a fixing member 15, a liquid injection member 16, and an electrolytic solution (not shown). Although omitted in FIG. 3, actually 20 power storage cells 10 are arranged side by side in one direction.

[0014] The current collector member 11 is formed in a flat plate shape. In the case of the positive electrode, the current collector member 11 is composed of, for example, aluminum foil, and in the case of the negative electrode, the current collector member 11 is composed of, for example, copper foil. However, the current collector member 11 may be composed of nickel foil, stainless steel foil, a clad foil combining aluminum foil and copper foil, or the like.

[0015] The positive electrode active material layer 12 is provided on one surface of the current collector member 11. The negative electrode active material layer 13 is provided on the other surface of the current collector member 11.

[0016] The separator 14 is provided between the positive electrode active material layer 12 provided on one current collector member 11 and the negative electrode active material layer 13 provided on the current collector member 11 adjacent to the one current collector member 11.

[0017] A positive electrode tab (not shown) is connected to the current collector member 11 disposed at one end in the thickness direction of the current collector members 11 among the plurality of power storage cells 10 arranged in one direction. A negative electrode tab (not shown) is connected to the current collector member 11 disposed at the other end in the thickness direction among the plurality of power storage cells 10 arranged in one direction.

[0018] The fixing member 15 fixes the peripheral edges of the current collector members 11 to each other. The fixing member 15 is made of, for example, resin. The fixing member 15 is provided with a communication port 15h that communicates the inside of the power storage cell 10 with the outside.

[0019] The liquid injection member 16 is fixed to the fixing member 15. More specifically, the liquid injection member 16 is fixed to the fixing member 15 so as to surround the communication port 15h. The liquid injection member 16 is made of, for example, resin. As shown in FIGS. 1 and 3, the liquid injection member 16 has a liquid injection port 16h for injecting the electrolytic solution from outside the power storage cell 10 into the power storage cell 10. The liquid injection port 16h communicates with the communication port 15h. In the present embodiment, the liquid injection member 16 is formed in a cylindrical shape defining the liquid injection port 16h, and more specifically, in a rectangular tube shape. However, the liquid injection member 16 is not limited to the rectangular tube shape and may be formed in a cylindrical shape or the like. In FIG. 3, for the sake of clarity of the invention, a schematic view showing one liquid injection member 16 attached to a portion of the fixing member 15 surrounding one power storage cell 10 is shown, but the present invention is not limited thereto, and one liquid injection member 16 may be attached to a portion of the fixing member 15 surrounding a plurality of stacked power storage cells 10.

[0020] As shown in FIGS. 1 and 3, the liquid injection member 16 has a receiving surface 16a for receiving the sealing member 20. The receiving surface 16a is formed flat.

[0021] The sealing member 20 has flexibility and can seal the liquid injection port 16h. The sealing member 20 is made of resin formed in a sheet shape. As shown in FIGS. 2 and 3, the sealing member 20 has an annular contact portion 21 and an inner portion 22.

[0022] The annular contact portion 21 is in contact with the receiving surface 16a of the liquid injection member 16. The annular contact portion 21 is welded to the receiving surface 16a.

[0023] The inner portion 22 is located inside the annular contact portion 21. As shown in FIG. 3, the inner portion 22 is recessed from the annular contact portion 21.

[0024] Next, a method for manufacturing the power storage module 1 will be described with reference to FIGS. 4 to 8. This manufacturing method includes a preparation step, a fixing step, a measurement step, a depressurization step, a sealing step, a re-measurement step, and a determination step.

[0025] In the preparation process, the power storage module 1 including the above-described power storage cell 10 is prepared. FIG. 4 shows a state in which four power storage modules are sandwiched between a pair of pressing plates 50 from both sides in the one direction. Note that in FIG. 4, the illustration of one of the pair of pressing plates 50 is omitted. Further, FIG. 4 shows a schematic view of a state in which four power storage modules are arranged in one direction, and the number of the liquid injection members 16 in each power storage module is different from that in FIG. 1. In this state, the electrolytic solution is injected into the power storage cell 10 through each liquid injection port 16h and communication port 15h.

[0026] In the fixing process, the sealing member 20 is fixed to the liquid injection member 16. Specifically, the sealing member 20 is placed and fixed on the receiving surface 16a of the liquid injection member 16. For example, the sealing member 20 is fixed by being welded to the receiving surface 16a of the liquid injection member 16. At this time, a gap is formed without welding a part of the receiving surface 16a and a part of the sealing member 20.

[0027] In the measurement process, the shape of the sealing member 20 attached to the liquid injection member 16 so as to cover the liquid injection port 16h before depressurizing the inside of the power storage cell 10 is measured. As shown in FIG. 6, in the measurement process, the measuring device 100 is used, and the three-dimensional shape of the sealing member 20 is measured by a light cutting method, a pattern projection method, or the like.

[0028] In the depressurizing process, in the power storage module 1 after the measurement process, the inside of the power storage cell 10 is depressurized. In this process, for example, the power storage module 1 in a state where the sealing member 20 is fixed to the liquid injection member 16 is placed in the chamber, and the inside of the chamber is evacuated so that the inside of the power storage cell 10 is depressurized until it becomes below atmospheric pressure. At this time, the gas inside the power storage cell 10 is discharged to the outside of the power storage cell 10 through the gap between the receiving surface 16a of the liquid injection member 16 and the sealing member 20. Note that the sealing member 20 and the liquid injection member 16 may be provided with gas vent holes, and the gas inside the power storage cell 10 may be discharged to the outside of the power storage cell 10 through the gas vent holes.

[0029] The sealing process is performed after the depressurization process or while the evacuation of the chamber is continued. Specifically, the gap between the annular contact portion 21 of the sealing member 20 and the receiving surface 16a of the liquid injection member 16 is welded, thereby closing the liquid injection port 16h. As a result, the power storage cell 10 is sealed in a state where the inside of the power storage cell 10 is depressurized.

[0030] In the remeasurement process, the shape of the sealing member 20 after the depressurization process in the power storage module 1 in a state where the power storage cell 10 is sealed in the sealing process is measured again. Specifically, the power storage module 1 is taken out from the chamber, for example, under atmospheric pressure. At this time, as shown in FIG. 7, the inner portion 22 of the sealing member 20 is deformed so as to be recessed toward the inside of the power storage cell 10 with respect to the annular contact portion 21. Thereafter, in the same manner as in the measurement process, the three-dimensional shape of the sealing member 20 is measured by the measuring device 100. In FIG. 7, the sealing member 20 before deformation is shown by a two-dot chain line.

[0031] In the determination process, the displacement amount D (see FIG. 7) of the sealing member 20 is calculated based on the measurement result in the measurement process and the measurement result in the remeasurement process, and when the displacement amount D is equal to or greater than the reference value D1, it is determined that the internal pressure P of the power storage cell 10 is appropriate. The displacement amount D is preferably, for example, the displacement of the central portion of the inner portion 22 before and after the depressurization process.

[0032] FIG. 8 is a graph showing the relationship between the displacement amount D of the sealing member 20 and the degree of depressurization of the internal pressure P of the power storage cell 10 from atmospheric pressure. As shown in FIG. 8, it can be seen that the displacement amount D increases as the degree of depressurization of the power storage cell 10 increases. Through simulation and preliminary experiments, it has been confirmed that when the displacement amount D becomes D1 or more, the internal pressure P of the power storage cell 10 becomes equal to or less than the appropriate value P1 below atmospheric pressure. Therefore, in the determination process, when the displacement amount D is equal to or greater than the reference value D1, it is determined that the internal pressure P of the power storage cell 10 is appropriate. In FIG. 8, the range where the internal pressure of the power storage cell 10 is greater than the appropriate value P1 is hatched.

[0033] As described above, in the method for manufacturing the power storage module 1, in the determination step, the displacement amount D of the sealing member 20 is calculated based on the shape of the sealing member 20 before and after the depressurization step, and when the displacement amount D is equal to or greater than the reference value D1, it is determined that the internal pressure P of the power storage cell 10 is appropriate. Therefore, a power storage module 1 in which the internal pressure P of each power storage cell 10 is appropriate is manufactured.

[0034] In addition, in the above embodiment, a bipolar type power storage module is exemplified as the power storage module 1, but the power storage module 1 is not limited thereto. A bipolar type cell is a cell having a structure in which a positive electrode active material layer 12 is provided on one surface of a single current collector member 11 and a negative electrode active material layer 13 is provided on the other surface, and a plurality of such structures are laminated with a separator 14 interposed therebetween.

[0035] Also, as shown in FIG. 9, the three liquid injection members 16 arranged in the one direction (the lamination direction of the current collector member 11, the positive electrode active material layer 12, and the negative electrode active material layer 13) may be connected to each other. In this case, the liquid injection ports 16h of the three liquid injection members 16 connected to each other may be collectively closed by one sealing member 20.

[0036] Alternatively, as shown in FIG. 10, the ten liquid injection members 16 arranged in the direction orthogonal to the one direction may be connected to each other.

[0037] Alternatively, as shown in FIG. 11, all the liquid injection members 16 may be connected to each other.

[0038] Those skilled in the art will understand that the above-described exemplary embodiments are specific examples of the following aspects.

[0039] The manufacturing method of the power storage module in the above embodiment includes a preparation step of preparing at least one power storage cell including a liquid injection member having a liquid injection port for injecting an electrolytic solution, a fixing step of attaching and fixing the sealing member to the liquid injection member so that the liquid injection port is covered with the sealing member that is flexible and can seal the liquid injection port, a measuring step of measuring the shape of the sealing member fixed to the liquid injection member, a depressurizing step of depressurizing the inside of the power storage cell after the measuring step, a sealing step of sealing the power storage cell after the depressurizing step, a re-measuring step of measuring the shape of the sealing member again after the sealing step, and a determination step of calculating the displacement amount of the sealing member based on the measurement result in the measuring step and the measurement result in the re-measuring step, and determining that the internal pressure of the power storage cell is appropriate when the displacement amount is equal to or greater than a reference value.

[0040] In this manufacturing method of the power storage module, in the determination step, the displacement amount of the sealing member is calculated based on the shape of the sealing member before and after the depressurizing step, and it is determined that the internal pressure of the power storage cell is appropriate when the displacement amount is equal to or greater than a reference value. Therefore, a power storage module with an appropriate internal pressure for each power storage cell can be manufactured.

[0041] Also, in the fixing step, the sealing member is fixed to the liquid injection member so that a gap is formed between the liquid injection member and the sealing member. In the depressurizing step, the inside of the power storage cell is depressurized by discharging the gas inside the power storage cell through the gap. In the sealing step, it is preferable to seal the inside of the power storage cell by welding the sealing member to the liquid injection member so that the gap is blocked.

[0042] In this aspect, since the liquid injection port is also used for depressurization, the structure is simplified compared to the case where a dedicated opening for depressurization is provided in the power storage cell.

[0043] Further, the at least one power storage cell prepared in the preparation step includes a plurality of power storage cells, and two or more of the liquid injection members in each of the plurality of power storage cells may be connected to each other. In this case, in the fixing step, it is preferable that the liquid injection ports in the two or more liquid injection members connected to each other are collectively covered by one of the sealing members.

[0044] In this aspect, compared with the case where a sealing member corresponding to each liquid injection port is prepared, the number of sealing members is reduced, so that the management and handling of the sealing members are simplified. In addition, since the boundary frame portions between adjacent liquid injection members become common and the welding locations of the sealing members to the liquid injection members are reduced, production becomes easier.

[0045] Further, in the preparation step, it is preferable to prepare a bipolar type power storage cell as the power storage cell.

[0046] In a power storage module including a bipolar type cell as a power storage cell, for power storage cells other than the power storage cell disposed on the outermost side in the one direction among the plurality of power storage cells, it is difficult to determine the internal pressure of the power storage cell based on the appearance, so the above effects are particularly remarkable.

[0047] Further, a power storage module according to an aspect of the present disclosure includes at least one power storage cell each having a liquid injection port for injecting an electrolytic solution, and a sealing member having flexibility and sealing the liquid injection port of the at least one power storage cell. The at least one power storage cell includes a liquid injection member having the liquid injection port. The liquid injection member is formed in an annular shape and has a receiving surface for receiving the sealing member. The sealing member includes an annular contact portion in contact with the receiving surface and an inner portion located inside the annular contact portion. The inner portion is recessed from the annular contact portion, and the internal pressure of the power storage cell is below atmospheric pressure.

[0048] It should be noted that the embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the description of the above embodiments, and further includes all modifications within the meaning and scope equivalent to the scope of claims.

Explanation of Reference Numerals

[0049] 1 Power storage module, 10 Power storage cells, 11 Current collecting member, 12 Positive electrode active material layer, 13 Negative electrode active material layer, 14 Separator, 15 Fixing member, 15h Communication port, 16 Liquid injection member, 16a Receiving surface, 16h Liquid injection port, 20 Sealing member, 21 Annular contact portion, 21h Through hole, 22 Inner portion.

Claims

1. A preparation step of preparing at least one power storage cell including a liquid injection member having a liquid injection port for injecting an electrolytic solution; A fixing step of attaching and fixing the sealing member to the liquid injection member so that the liquid injection port is covered with the sealing member having flexibility and capable of sealing the liquid injection port; A measuring step of measuring the shape of the sealing member fixed to the liquid injection member; A depressurization step of depressurizing the inside of the power storage cell after the measuring step; A sealing step of sealing the power storage cell after the depressurization step; A re-measuring step of measuring the shape of the sealing member again after the sealing step; A determination step of calculating the displacement amount of the sealing member based on the measurement result in the measurement step and the measurement result in the re-measurement step, and determining that the internal pressure of the power storage cell is appropriate when the displacement amount is equal to or greater than a reference value. A method for manufacturing a power storage module comprising the steps of:

2. In the fixing step, the sealing member is fixed to the liquid injection member so that a gap is formed between the liquid injection member and the sealing member, In the depressurization step, the inside of the power storage cell is depressurized by discharging the gas inside the power storage cell through the gap, In the sealing step, the inside of the power storage cell is sealed by welding the sealing member to the liquid injection member so that the gap is closed. The method for manufacturing a power storage module according to claim 1.

3. The at least one power storage cell prepared in the preparation step includes a plurality of power storage cells, and two or more of the liquid injection members among the respective liquid injection members in the plurality of power storage cells are connected to each other, In the fixing step, the liquid injection ports in two or more of the liquid injection members connected to each other are collectively covered by one sealing member. The method for manufacturing a power storage module according to claim 1 or 2.

4. In the preparation step, a bipolar type power storage cell is prepared as the power storage cell. The method for manufacturing a power storage module according to any one of claims 1 to 3.

5. A plurality of power storage cells each having a liquid injection port for injecting an electrolytic solution; A sealing member having flexibility and sealing each of the liquid injection ports of the plurality of power storage cells, Each of the plurality of power storage cells, A plurality of current collecting members arranged side by side at intervals; A fixing member for fixing the peripheral edges of the current collecting members; And a liquid injection member fixed to the fixing member and having the liquid injection port. The fixing member is provided with a communication port that communicates the space inside the power storage cell with the liquid injection port. The liquid injection member is formed in an annular shape and has a receiving surface for receiving the sealing member. The sealing member includes an annular contact portion that contacts the receiving surface, and an inner portion located inside the annular contact portion. The inner portion is recessed from the receiving surface toward the fixing member. The power storage module has an internal pressure of the power storage cell that is equal to or lower than atmospheric pressure.

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