Packing case for thin-film electronic device and method of packing

Abstract

To provide a packing case capable of preventing electrostatic breakdown due to electrification of a thin-film electronic device and a method of packing using the same.SOLUTION: A packing case 1 according to the present invention, for packing a thin-film electronic device 10 such as a solar cell element, comprises a case body 2 that defines an accommodation space 1S for one or a plurality of thin-film electronic devices 10. A case material making up at least part of the case body 2 has a volume resistivity equal to or smaller than 1×105 Ω cm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a packaging case and a packaging method for thin-film electronic devices such as solar cell elements. [Background technology]

[0002] Thin-film solar cells are known as one type of thin-film electronic device. Small thin-film solar cells are mounted in, for example, wristwatches and small electronic devices to continuously supply power to electronic circuits. When manufactured thin-film solar cells are shipped as products, the many thin-film solar cell elements on the collective substrate are separated into individual pieces and then packed in a packaging case. In this case, multiple solar cell elements are often stored stacked or individually laid flat.

[0003] Regarding packing cases for solar cell elements, for example, Patent Document 1 describes a packing case for solar cell elements that houses an element assembly in which a plurality of solar cell elements are stacked. This packing case includes a main body having an opening and a bottom and a recess formed therein capable of housing the element assembly, and a support part having a first part that can support the side of the element assembly facing the bottom side in a mounting state when the element assembly is housed in the recess, and a second part that can be fixed to the main body at a position closer to the opening than the first part. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-234654 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, insulating plastics are often used as the material for this type of packaging case. However, due to vibration during transportation, the solar cell elements may rub against each other or against the packaging case, which can cause the front and back surfaces of the solar cell elements to become charged. This increased charge can lead to electrostatic breakdown of the solar cell elements. This tendency is particularly pronounced in thin-film solar cell elements that use film substrates, but it is also a problem that can occur in thin-film electronic devices other than solar cell elements.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a packaging case and a packaging method that can prevent electrostatic damage to solar cell elements and other thin-film electronic devices. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a packaging case for a thin film electronic device, which comprises a case body that defines a storage space for one or more thin film electronic devices, and the volume resistivity of a case material that constitutes at least a part of the case body is 1×10 5 It is characterized by a resistance of Ω·cm or less.

[0008] According to the present invention, static electricity generated inside the case due to vibrations during transportation or the like can be released to the outside of the case, thereby reducing the charged voltage of thin-film electronic devices inside the packing case and preventing electrostatic breakdown.

[0009] The volume resistivity of the case material is preferably 10 Ω·cm or more. If the volume resistivity of the case material is 10 Ω·cm or more, damage to the solar cell element housed in the case can be prevented.

[0010] The case material is preferably a resin material containing a conductive material, in which case the conductive material is carbon, and the resin material is preferably any one of ABS resin, polybutylene terephthalate (PBT), polyethylene (PE), polycarbonate (PC), and fluororesin.

[0011] The thin-film electronic device is preferably a thin-film solar cell element, which preferably includes a flexible film substrate, a first electrode layer provided on the film substrate, a power generation layer provided on the first electrode layer, a second electrode layer provided on the power generation layer, and a protective layer provided on the second electrode layer.

[0012] The case body preferably has a sidewall portion surrounding the periphery of the storage space capable of storing a stack of the plurality of thin-film electronic devices, and at least the sidewall portion is made of the case material. Since the inner peripheral surface of the sidewall portion is the portion that comes into contact with the thin-film electronic devices, it is preferable that the volume resistivity of the sidewall portion be set to 1×10 5 By keeping the resistance at Ω·cm or less, it is possible to reduce the charging voltage of thin-film electronic devices inside the packing case and prevent electrostatic breakdown.

[0013] The packing case according to the present invention preferably further comprises cushioning materials provided at the top and bottom of the storage space, thereby making it possible to protect the solar cell elements stored in the case.

[0014] In the packing case according to the present invention, it is preferable that the plurality of storage spaces capable of individually storing each of the plurality of thin-film electronic devices are provided in a plane, and in this case too, the solar cell elements stored in the case can be protected.

[0015] The packing case according to the present invention preferably further comprises a cover member for closing the opening of the case body, the cover member being made of the case material, and the present invention can further reduce the probability of electrostatic breakdown of the thin-film electronic device.

[0016] In the present invention, the planar size of the storage space is 100 cm 2 It is preferable that the following conditions are satisfied: As described above, the packing case according to the present invention is suitable as a case for storing small thin-film electronic devices.

[0017] The method for packaging thin-film electronic devices according to the present invention is characterized in that one or more thin-film electronic devices are packaged in the above-described packaging case according to the present invention. According to the present invention, static electricity generated inside the case due to vibrations during transportation or the like can be released to the outside of the case, thereby reducing the charged voltage of the thin-film electronic devices inside the packaging case. Therefore, electrostatic damage to the thin-film electronic devices can be prevented. [Effects of the Invention]

[0018] As described above, the present invention can provide a packing case and a packing method that can prevent electrostatic damage to thin-film electronic devices. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic side cross-sectional view showing the configuration of a packing case for thin-film electronic devices according to a first embodiment of the present invention, particularly showing the state in which thin-film electronic devices are housed. [Figure 2] FIG. 2 is a schematic side cross-sectional view showing the configuration of a packing case for a thin-film electronic device according to the first embodiment of the present invention, particularly showing the state in which the thin-film electronic device has been removed. [Figure 3] FIG. 3 is a schematic cross-sectional view showing an example of the configuration of a thin-film electronic device. [Figure 4] FIG. 4 is a schematic cross-sectional plan view of the packing case shown in FIG. [Figure 5] FIG. 5 shows the configuration of a packaging case for thin-film electronic devices according to a second embodiment of the present invention, where (a) is a schematic plan view and (b) is a schematic side cross-sectional view. [Figure 6] FIG. 6 is a graph showing the charging voltage of the solar cell element for each material of the packing case. [Figure 7] FIG. 7 is a graph showing the results of Weibull analysis of electrostatic withstand voltage tests of thin-film solar cell elements according to the comparative example and the example. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0021] 1 and 2 are schematic side cross-sectional views showing the configuration of a packaging case for thin-film electronic devices according to a first embodiment of the present invention, with FIG. 1 showing the state in which a thin-film electronic device is housed and FIG. 2 showing the state in which the thin-film electronic device has been removed.

[0022] 1 and 2, the packing case 1 according to this embodiment is capable of storing a plurality of thin-film electronic devices 10 in a stacked state, and includes a case body 2 that defines a storage space 1S for the thin-film electronic devices 10, and a lid member 3 that closes an opening 2o of the case body 2. The case body 2 has side walls 2a and a bottom 2b, and forms a single storage space 1S. Cushioning materials 4a and 4b are provided at the top and bottom of the storage space 1S, respectively, and the stack of a plurality of thin-film electronic devices 10 is stored sandwiched between the cushioning materials 4a and 4b.

[0023] FIG. 3 is a schematic cross-sectional view showing an example of the structure of the thin-film electronic device 10. As shown in FIG.

[0024] 3, the thin-film electronic device 10 is, for example, a solar cell element, and has a structure in which a film substrate 11, a first electrode layer 12, a power generation layer 13, a second electrode layer 14, and a protective layer 15 are laminated in this order. The film substrate 11 and the first electrode layer 12 are transparent, and light incident on the film substrate 11 passes through the first electrode layer 12 to reach the power generation layer 13, where it is photoelectrically converted by the power generation layer 13. The power generation layer 13 is, for example, an amorphous silicon layer.

[0025] The solar cell element according to this embodiment is an extremely thin element with a thickness of about 200 μm, using a flexible film substrate. Thin-film solar cell elements are preferably used in small electronic devices such as wristwatches and mobile terminals, and have a relatively small planar size. For example, the planar shape of a thin-film solar cell element for a wristwatch is approximately circular, with a diameter of about 20 to 40 mm. The planar shape of the thin-film electronic device 10 is not limited to being approximately circular, and may be, for example, approximately rectangular.

[0026] The planar size of the storage space 1S of the packing case 1 in which such a thin-film electronic device 10 is stored is 100 cm 2 It is preferable that the depth (height) of the storage space 1S is 0.2 to 20 mm. As described above, the thin-film electronic device 10 such as a thin-film solar cell element to be stored in the packing case 1 is very small and thin, and therefore the packing case 1 is also very small.

[0027] The case body 2 of the packing case 1 is made of a resin containing a conductive material, and a conductive filler such as carbon black powder is mixed in, resulting in a volume resistivity of 1×10 5 Ω·cm or less (or sheet resistivity is 1×10 6 It is preferable that the resin material is a thermoplastic resin having a resistivity of Ω / sq or less. The resin material is preferably any one of ABS resin, polybutylene terephthalate (BPT), polyethylene (PE), polycarbonate (PC), and fluororesin (polytetrafluoroethylene).

[0028] The case body 2 is a member that comes into contact with the thin-film electronic device 10, but the lid member 3 is insulated and separated from the thin-film electronic device 10 by the cushion material 4a, and therefore the lid member 3 does not come into contact with the thin-film electronic device 10. Therefore, the lid member 3 does not need to be made of a resin containing a conductive material, but may be formed using a resin containing a conductive material.

[0029] The volume resistivity of the conductive resin is preferably 10 Ω·cm or more. If the volume resistivity is too low, there is a risk that the solar cell elements may be damaged by the impulse current flowing through the packing case 1. However, if the volume resistivity is 10 Ω·cm or more, damage to the solar cell elements can be prevented.

[0030] FIG. 4 is a schematic cross-sectional plan view of the packing case shown in FIG.

[0031] As shown in Fig. 4, it is preferable that the inner peripheral surface 2s of the side wall 2a of the case body 2 of the packing case 1 has protrusions 2p protruding perpendicularly from the inner peripheral surface 2s formed at at least three locations in the circumferential direction. The protrusions 2p are formed continuously (linearly) in the height direction of the side wall 2a. Multiple thin-film electronic devices 10 are stacked horizontally within the packing case 1, and except for the top and bottom thin-film electronic devices 10, the only surfaces that come into contact with the packing case 1 are the outer peripheral surfaces 10s (side surfaces). Therefore, when the protrusions 2p are provided on the inner peripheral surface 2s of the case body 2, the contact area between the case body 2 and the outer peripheral surfaces 10s of the thin-film electronic devices 10 can be reduced, thereby suppressing the generation of static electricity.

[0032] When a resin material with high volume resistivity is used in conventional packaging cases, vibrations during transportation can cause the electrostatic voltage on the front and back surfaces of the thin-film solar cell element to reach a high voltage of approximately 600 to 1200 V. However, when a packaging case using a resin material containing a conductive material as in this embodiment is used, the electrostatic voltage on the front and back surfaces of the thin-film solar cell element is kept to 400 V or less, thereby preventing electrostatic breakdown of the thin-film solar cell element.

[0033] While stacking multiple thin-film electronic devices 10 provides efficient packaging, it has the drawback of making it difficult to remove the devices one by one due to the effects of static electricity, which can cause the upper and lower devices to stick together. However, according to this embodiment, the effects of static electricity can be reduced, preventing electrostatic damage to the devices and making them easier to remove.

[0034] FIG. 5 shows the configuration of a packaging case for thin-film electronic devices according to a second embodiment of the present invention, where (a) is a schematic plan view and (b) is a schematic side cross-sectional view.

[0035] As shown in Figures 5(a) and 5(b), the packing case 1 according to this embodiment is characterized in that it includes a plurality of storage spaces 1S for individually storing a plurality of thin-film electronic devices 10. That is, the packing case 1 includes a case body 2 having a plurality of recesses 2d formed therein and a lid member 3 for covering the upper surface of the case body 2. The plurality of recesses 2d constituting the storage spaces 1S may be arranged two-dimensionally as shown in the figure, or may be arranged one-dimensionally. This packing case 1 is a stack-type case that can be transported stacked in multiple layers.

[0036] In the packing case 1 according to this embodiment, not only the case body 2 but also the lid member 3 can come into contact with the thin-film electronic device 10. Therefore, both the case body 2 and the lid member 3 are made of conductive resin, and a conductive filler such as carbon black powder is mixed in to form a packing case 1 having a volume resistivity of 1×10 5 It is preferable that the resin be a conductive thermoplastic resin with a resistance of Ω·cm or less. That is, the case body 2 and the cover member 3 are made of a resin containing a conductive material. As described above, the resin material is preferably any one of ABS resin, polybutylene terephthalate (BPT), polyethylene (PE), polycarbonate (PC), and fluororesin (polytetrafluoroethylene).

[0037] The packing case 1 according to this embodiment can achieve the same effects as the packing case 1 according to the first embodiment. That is, the packing case 1 is made of a resin containing a conductive material, and static electricity generated inside the case due to vibrations during transportation can be released to the outside, thereby reducing the charging voltage of the solar cell elements and preventing electrostatic breakdown of the solar cell elements.

[0038] The above describes a preferred embodiment of the present invention, but the present invention is not limited to the above embodiment, and various modifications are possible within the scope of the present invention, and it goes without saying that these modifications are also included within the scope of the present invention.

[0039] For example, in the first embodiment, the entire case body 2 is made of a resin material containing a conductive material, and the volume resistivity is 1×10 5 Although the example given above shows a case where the resistance is Ω·cm or less, the present invention is not limited to this configuration. For example, the case material constituting the side wall portion 2a may be made of a resin material containing a conductive material, and the bottom portion 2b may be made of a resin material that does not contain a conductive material.

[0040] In the first embodiment, the opening 2o is provided only on the upper side of the case body 2 and is closed by the lid member 3, but openings may be provided on both the upper and lower sides of the case body 2, with the upper opening closed by a top lid and the lower opening closed by a bottom lid. Also, a stack of a predetermined number of thin-film electronic devices 10 may be considered as one set, and multiple sets may be housed in the case body 2, with cushioning material separating the upper and lower sets.

[0041] The above-described form of the packing case is merely an example, and the packing case may take various forms. For example, it is possible to combine the first and second embodiments and accommodate a stack of multiple thin-film electronic devices 10 in each of multiple recesses 2d arranged one-dimensionally or two-dimensionally. [Example]

[0042] (Charge amount evaluation test) In order to reproduce the charged state of thin-film solar cell elements during packaging and transportation, measurement samples of multiple solar cell elements packed in the packing case shown in Figure 1 were placed flat on an aluminum plate, and after previously discharging the charge to below 10 V using an ionizer, they were vibrated up and down and left and right 500 times.

[0043] The materials used for the packing cases were six levels: aluminum, carbon-containing ABS, carbon-containing PBT, carbon-containing PC, PE, and PTFE (polytetrafluoroethylene). When the resistivity of each case material was checked, the volume resistivity of the carbon-containing ABS was 1 x 10 3 Ω·cm, and the volume resistivity of carbon-containing PBT and carbon-containing PC is 1×10 5 The volume resistivity of PE was 1×10 16 Ω·cm, and the volume resistivity of PTFE is 1×10 18 The resistance was Ω·cm.

[0044] Next, in order to measure the charged state of the thin-film solar cell element, the lid member (Al or black cushion material) of the packing case was removed, and a static electricity tester was placed directly above the sample to measure the amount of charge.

[0045] When it was time to measure the next sample, the top sample was removed using air tweezers. If the top and bottom samples were stuck together and could not be separated, the bottom sample was pressed down with plastic tweezers to remove the top sample. The potential of the newly topmost sample was then measured with an electrostatic tester. By repeating the above process, the charge amounts of all the thin-film solar cell elements in the packaging case were measured.

[0046] FIG. 6 is a graph showing the charging voltage of the thin-film solar cell element for each material of the packing case.

[0047] As shown in Figure 6, the charged voltage of the sample in the aluminum packing case was approximately 10 V, the charged voltage of the sample in the carbon-containing ABS packing case was approximately 150 V, the charged voltage of the sample in the carbon-containing PBT packing case was approximately 250 V, and the charged voltage of the sample in the carbon-containing PC packing case was 300 V. The charged voltage of the sample in the PE packing case was 550 to 1200 V, and the charged voltage of the sample in the PTFE packing case was 1200 to 1700 V.

[0048] (Electrostatic discharge test) A predetermined number of thin-film solar cell elements were packed in the packaging format shown in Fig. 1, and the packing case was vibrated up and down and left and right 500 times to simulate the electrostatic charge state during transportation. Two types of packing cases were used: a packing case made of PE that does not contain carbon (Comparative Example) and a packing case made of ABS that contains carbon (Example). Each packing case contained 30 thin-film solar cell elements.

[0049] After applying vibration to the packing case, the thin-film solar cell elements were removed one by one from the packing case, and a predetermined bias voltage was applied between the electrodes of the thin-film solar cell elements in the forward and reverse directions. The bias voltage started at 100 V and was increased in steps of 100 V to 200 V, 300 V, and so on.

[0050] Each time a specific bias voltage was applied, the open-circuit voltage (Voc) of the solar cell was measured to determine whether or not it had failed. That is, the bias voltage was varied from low to high, and the voltage level at which the solar cell failed was evaluated. A threshold value 5% lower than the initial value at each applied voltage was used to determine whether or not the solar cell had failed, and a measured voltage below the threshold was deemed to have failed. The failure rate for each bias voltage was then calculated and plotted on a Weibull analysis diagram (bias voltage-unreliability relationship diagram). An approximate line was then calculated from these plotted values, and the unreliability at a bias voltage of 150V was calculated from the approximate line (bias voltage-unreliability relationship equation).

[0051] FIG. 7 is a graph showing the Weibull analysis results of the electrostatic withstand voltage test of the thin-film solar cell elements according to the comparative example and the example, where the horizontal axis represents the bias voltage (V) applied to the thin-film solar cell element, and the vertical axis represents the unreliability (%) of the thin-film solar cell element.

[0052] As shown in Figure 7, in the case of the packing case of the comparative example using PE that does not contain carbon, failure first occurred when the bias voltage was 300 V, with an unreliability of 12.1% at this time, 41.8% at 400 V, and 97.7% at 500 V. Furthermore, the unreliability when the bias voltage was 150 V, calculated from the approximation line, was 0.121%.

[0053] In contrast, for the packing case of the example using carbon-containing ABS, the unreliability was 2.3% when the bias voltage was 300 V, 15.4% when it was 400 V, 41.8% when it was 500 V, and 97.7% when it was 600 V. Furthermore, the unreliability when the bias voltage was 150 V, calculated from the approximation line, was 0.015%, an order of magnitude lower than that of the comparative example. In other words, the reliability of the packing case of the example was more than 10 times higher than that of the comparative example. [Explanation of symbols]

[0054] 1 packing case 1S storage space 2 Case body 2a Side wall of the case body 2b Bottom of the case 2d Recessed part of the case body 2o Case body opening 2p Protrusion on the case body 2s Inner surface of the case body 3 Cover member 4a, 4b Cushioning material 10 Thin-film electronic devices 10s Outer surface of thin film electronic devices 11 Film substrate 12 1st electrode layer 13 Power generation layer 14 Second electrode layer 15 Protective layer

Claims

1. A packaging case for packaging one or more thin film electronic devices, comprising: a case body defining a space for accommodating the thin-film electronic device; The volume resistivity of the case material constituting at least a part of the case body is 1×10 ５ A packing case characterized by having a resistance of Ω·cm or less.

2. 2. The packing case according to claim 1, wherein the case material has a volume resistivity of 10 Ω·cm or more.

3. 2. The packaging case according to claim 1, wherein the case material is a resin material containing a conductive material.

4. the conductive material is carbon; 4. The packing case according to claim 3, wherein the resin material is any one of ABS resin, polybutylene terephthalate (PBT), polyethylene (PE), polycarbonate (PC), and fluororesin.

5. The packaging case according to claim 1 , wherein the thin-film electronic device is a thin-film solar cell element.

6. 6. The packing case according to claim 5, wherein the thin-film solar cell element has a flexible film substrate, a first electrode layer provided on the film substrate, a power generation layer provided on the first electrode layer, a second electrode layer provided on the power generation layer, and a protective layer provided on the second electrode layer.

7. the case body includes a sidewall portion surrounding the periphery of the storage space capable of storing a stack of the plurality of thin-film electronic devices; The packing case according to claim 1 , wherein at least the side wall portion is made of the case material.

8. The packing case according to claim 7, further comprising cushioning materials provided at the top and bottom of the storage space.

9. The packing case according to claim 1 , wherein a plurality of the storage spaces capable of individually storing each of the plurality of thin-film electronic devices are provided in a plane.

10. Further, a cover member is provided to close the opening of the case body, The packing case according to claim 1 , wherein the cover member is formed from the case material.

11. The planar size of the storage space is 100 cm ２ 2. The packing case according to claim 1, wherein:

12. A method for packaging thin-film electronic devices, comprising packaging one or more thin-film electronic devices using the packaging case according to any one of claims 1 to 11.

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