JP2011249167A - Power storage device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device in which information about a temperature history from manufacturing a battery to using it can be sufficiently obtained and if any trouble occurs, its cause can be smoothly investigated.SOLUTION: A power storage device 1 includes a unit cell 2 and a resin exterior 5 covering that unit cell 2. In both a surface of the unit cell 2 and the resin exterior 5, temperature indicating sections 11, 12 are provided, respectively. Each of the temperature indicating sections 11, 12 is comprised of a temperature indicating material of which the color is irreversibly changed by reaching a set temperature.

Description

  The present invention relates to an electricity storage device including a unit cell and a resin sheathing material that covers the unit cell, and a manufacturing method thereof.

  Conventionally, an electricity storage device represented by a cylindrical lithium battery is well known. In this type of battery, a battery (unit cell) in a state where a plain outer can also serving as a positive electrode can or a negative electrode can is exposed, and a battery outer film as a resin outer member is wound around the battery in the circumferential direction. It has a structure.

  In this type of battery, as a means for insulating the positive electrode and the negative electrode, a resin component called a gasket is disposed at the interface between the two. In such a resin component, a use temperature range is determined for each material, and a predetermined quality is guaranteed for the battery as long as it is used within the range. However, if the temperature at which the battery is used is higher than the operating temperature range, deterioration of the resin material is unavoidable depending on the temperature, and as a result, satisfactory discharge performance cannot be obtained, or the electrolyte inside the battery May cause problems such as leakage.

  However, it is generally difficult to determine whether or not a battery has been used at a temperature that exceeds the operating temperature range, except when it is used at an extremely high temperature with respect to the assumed temperature. This is the reason for hindering the investigation of the cause.

  Under such circumstances, a battery having a portion made of a thermal dye (temperature indicating material) whose color changes irreversibly when the battery surface temperature rises to a predetermined high temperature has been proposed. (For example, refer to Patent Document 1). And according to this, it is supposed that it can be grasped comparatively simply and visually whether the battery is used at a temperature exceeding the operating temperature range. In addition, although the technical field is different from that described in Patent Document 1, some conventional proposals have been made with a portion made of a temperature indicating material for the convenience of determining whether or not it has been used at a temperature exceeding the operating temperature range. (See, for example, Patent Document 2).

JP 2000-277061 A JP 2004-18620 A

  In the case of the above prior art, when a temperature exceeding the operating temperature range is encountered during use, an irreversible change occurs in the color of the temperature indicating material, so that information on the temperature history during use can be obtained to some extent. Yes.

  By the way, it is not only during use that the battery encounters high temperatures. In other words, depending on the type of battery, there may be a process that temporarily exceeds the operating temperature range at the time of manufacture. In this case, even if the color change of the temperature indicating material is observed, the operating temperature range is set at any stage. It is not possible to know if a temperature exceeding the limit is encountered. For this reason, it was impossible to accurately identify at which stage the malfunction occurred, and the cause investigation could not be carried out smoothly.

  The present invention has been made in view of the above-mentioned problems, and its purpose is to sufficiently obtain information on the temperature history from the time of manufacture of the battery to the time of use, and to smoothly investigate the cause when a problem occurs. It is providing the electrical storage device which can be advanced, and its manufacturing method.

Means for solving the above problems are listed below.
[1] An electricity storage device including a unit cell and a resin sheathing material that covers the unit cell, wherein a temperature indicating portion made of a temperature indicating material whose color changes irreversibly by reaching a set temperature is provided on the unit cell. An electricity storage device provided on both a surface and a resin sheathing material. Therefore, according to the means 1, the temperature indicating portion on the surface of the unit cell is provided in the middle of the battery manufacturing stage, whereas the temperature indicating portion of the resin sheathing material is provided after the battery is almost completed. is there. Based on the change in color of these two types of temperature indicating portions, it is possible to objectively and sufficiently obtain information related to the temperature history from the time of manufacturing the battery to the time of use. Therefore, it can be set as the electrical storage device which can advance the cause investigation when a malfunction arises smoothly.

  [2] The electricity storage device according to means 1, wherein the temperature indicating material is a temperature indicating ink, and the temperature indicating portion is a printed portion printed using the temperature indicating ink. Therefore, according to the means 2, since it is sufficient to perform printing using the temperature indicating ink instead of the normally used ink, it is not accompanied by an increase in the number of parts and the number of processes, thereby preventing an increase in cost. Can do.

  [3] The electricity storage device according to means 2, wherein the printing unit is a printing unit also serving as a manufacturing code. Therefore, according to the means 3, the production code is normally printed on the battery, and this is used as a printing portion printed using the temperature indicating ink, so that not only the product information related to the battery is presented but also the production of the battery. It is possible to obtain information on the temperature history from time to use. Moreover, according to this structure, the information regarding the said temperature history can be obtained, without affecting the external appearance of a battery so much.

  [4] A transparent window portion that allows the unit cell to be visually recognized is formed in the resin sheathing material, and a temperature indicating portion on the unit cell side is disposed corresponding to the transparent window portion, The electricity storage device according to any one of means 1 to 3, wherein a temperature indicating portion on the resin exterior material side is disposed at a position different from the transparent window portion. Therefore, according to the means 4, by providing the transparent window portion, both the temperature indicating portion on the unit cell side and the temperature indicating portion on the resin exterior material side can be visually recognized without bothering removing the resin exterior material. Therefore, the information regarding the temperature history from the time of battery manufacture to the time of use can be easily confirmed.

  [5] A method of manufacturing an electricity storage device according to any one of means 1 to 4, wherein a first temperature indicating portion disposing step of providing the temperature indicating portion on a surface of the unit cell, a short of discharging the unit cell. A power storage device comprising: a time discharge step, a covering step of covering the unit cell with the resin sheathing material, and a second temperature indicating portion disposing step of providing the temperature indicating portion on the resin sheathing material in this order. Manufacturing method. Therefore, according to the means 5, it is known that the short-time discharge process for discharging the battery is accompanied by heat generation, and the temperature indication portion on the resin exterior material side provided by the second temperature-display portion arranging step is The color changes due to heat generation. On the other hand, the color of the unit cell side temperature indicating portion provided in the first temperature indicating portion disposing process is changed by heat generation before the short time discharging step in addition to after the short time discharging step. Therefore, based on changes in the colors of these two types of temperature indicating portions, it is possible to objectively and sufficiently obtain information related to the temperature history from the time of battery manufacture to the time of use through vision.

  As described in detail above, according to the inventions described in the means 1 to 5, it is possible to sufficiently obtain information on the temperature history from the time of manufacture of the battery to the time of use, and smoothly investigate the cause when a problem occurs. It is possible to provide a power storage device that can be used and a method for manufacturing the same.

(A) is a schematic perspective view which shows the manufacturing process of the cylindrical lithium battery of one Embodiment which actualized this invention, (b) is a schematic perspective view which shows the completed cylindrical lithium battery, (c)-(f). Is an enlarged cross-sectional view of a main part showing two temperature indicating parts. The flowchart for demonstrating the manufacturing method of the said embodiment. (A) is a schematic perspective view which shows the cylindrical lithium battery of another embodiment which actualized this invention, (b) is a principal part expanded sectional view which shows two temperature display parts. The schematic perspective view which shows the cylindrical lithium battery of another embodiment which actualized this invention. (A) is a schematic perspective view which shows the manufacturing process of the assembled battery of one Embodiment which actualized this invention, (b) is a schematic perspective view which shows the completed assembled battery.

  Hereinafter, an embodiment in which a power storage device and a manufacturing method thereof according to the present invention are embodied in a cylindrical lithium battery and a manufacturing method thereof will be described in detail with reference to the drawings.

  As shown in FIGS. 1A and 1B, a unit cell 2 as a constituent element of the cylindrical lithium battery 1 includes a plain and metal outer can 3 that also serves as a positive electrode can. A disc-shaped negative electrode terminal plate 4 is attached to the opening of the outer can 3 via a resin gasket (not shown). A power generation element is accommodated in the space formed by the outer can 3 and the negative electrode terminal plate 4.

  The outer peripheral surface 3a of the outer can 3 is covered with a battery outer film 5 as a resin outer casing so as to be wound along the battery circumferential direction. The exterior film 5 of the present embodiment uses a heat-shrinkable resin film such as polyethylene terephthalate (PET) or polyvinyl chloride (PVC) as a base material. An image is printed. And in the case of this embodiment, the unit cell side printing part 11 (unit cell side temperature indicating part) printed using the temperature indicating ink is provided on the outer peripheral surface 3a of the outer can 3 in the unit cell 2. Here, the temperature indicating ink used in the present embodiment is a kind of temperature indicating material and is also called a thermal ink, and refers to an ink having a property that the color changes irreversibly when it reaches a set temperature. . The reason why the ink whose color change is irreversible is used is that it is suitable for checking the temperature history because the color does not recover even if the temperature drops after the color change. In addition, the unit cell side printing unit 11 of the present embodiment is a printing unit that also serves as a manufacturing code such as a product number, a manufacturing date, a recommended use date, and the like, and is expressed by a character string “AAABBB” for convenience of drawing drawing. Has been.

  In addition, a resin exterior material side printing portion 12 (resin exterior material side temperature indicating portion) printed using the temperature indicating ink is provided on the surface 5 a of the exterior film 5. The resin exterior material side printing portion 12 is also a printing portion that also serves as a production code such as a product number, a production date, a recommended use time limit, and the like, and is expressed by a character string “CCCDDD” for convenience of drawing drawing. . In addition, the description content by the unit cell side printing part 11 and the resin exterior material side printing part 12 may differ, and may be the same. Further, in the present embodiment, the resin exterior material side printing unit 12 is disposed so as to be overlapped at the position where the unit cell side printing unit 11 is disposed.

Next, the manufacturing method of the cylindrical lithium battery 1 of this embodiment is demonstrated according to the flowchart of FIG.
First, a unit cell 2 was produced as follows (see S1 in FIG. 2). As a basic material configuration, a positive electrode made of manganese dioxide, graphite, a binder (fluorine binder), a negative electrode made of lithium metal or an alloy thereof, a separator made of composite fiber using PP / PE resin, 1M LiClO ₄ A PC / DME electrolyte solution was used as the electrolyte. After these were accommodated in a metal outer can 3 as a positive electrode can, sealing was performed by placing a resin gasket in the opening of the outer can 3 and attaching a disk-shaped negative electrode terminal plate 4.

  Next, the 1st temperature-display part arrangement | positioning process was performed and the unit cell side printing part 11 was provided in the surface of the unit cell 2 (refer S2 of FIG. 2). Specifically, here, “WAX temperature ink: model number WL-85 (reaction temperature 85 ° C.)” manufactured by Asei Industry Co., Ltd. was used as the temperature ink. Note that a conventionally known method was used for printing. The unit cell side printing unit 11 is a printing unit that also serves as a manufacturing code.

  Next, a short-time discharge process for discharging the unit cell 2 was performed (see S3 in FIG. 2). This process is also a process accompanied by heat generation. However, in normal cases, the temperature does not reach the operating temperature range.

  Next, a covering step was performed to cover the unit cell 2 with the exterior film 5 (see S4 in FIG. 2). Specifically, the unit cell 2 was placed on the heat-shrinkable PET-made exterior film 5, and the exterior film 5 was wound so as to cover the entire outer peripheral surface 3 a of the exterior can 3. The upper end surface and the lower end surface of the unit cell 2 are not covered and are almost exposed. Then, the exterior film 5 was brought into close contact with the outer peripheral surface 3 a of the exterior can 3 by causing hot air to act on the exterior film 5 using a heat shrink furnace and causing the exterior film 5 to thermally contract. When hot air is applied, the battery surface temperature instantaneously reaches about 70 ° C to 80 ° C.

  Next, the 2nd temperature part arrangement | positioning process was performed and the resin exterior material side printing part 12 was provided in the surface of the exterior film 5 (refer S5 of FIG. 2). Here, as the temperature indicating ink, “WAX temperature indicating ink: model number WL-85 (reaction temperature 85 ° C.)” manufactured by Asei Industry Co., Ltd., that is, the same one used in the first temperature indicating portion disposing step was used. Note that a conventionally known method was used for printing. The resin exterior material side printing section 12 was a printing section that also served as a manufacturing code. The cylindrical lithium battery 1 having a diameter of 17 mmφ and a height of 45 mm was completed through the above steps.

  A method for investigating the cause when a defect occurs in the cylindrical lithium battery 1 manufactured in this way will be described.

  FIGS. 1C to 1F show two temperature indicating portions (unit cell side printing portion 11 and resin exterior material side printing portion 12) in the cylindrical lithium battery 1. In addition, regarding the unit cell side printing unit 11 and the resin exterior material side printing unit 12, those that are not hatched and expressed in white mean that no discoloration has occurred, while those that are expressed with hatching are discolored. It means that you are awake. In addition, the cylindrical lithium battery 1 of FIG.1 (c) shows the battery in which the malfunction has not generate | occur | produced, and in this battery, two temperature indicating parts are not discolored.

  On the other hand, the cylindrical lithium battery 1 shown in FIGS. 1 (d) to 1 (f) shows three types of batteries that have malfunctioned due to some cause. When investigating the cause of the defect, first, the resin exterior material-side printed portion 12 in the exterior film 5 is visually inspected, and further, a part or all of the exterior film 5 is peeled off to expose the surface of the unit cell 2. The battery side printing unit 11 may be visually inspected.

  In the battery shown in FIG. 1 (e), the resin exterior material side printing portion 12 of the two temperature indicating portions is not discolored, and only the unit cell side printing portion 11 is discolored. Therefore, in this case, it can be estimated that an unexpected temperature (in this case, a temperature exceeding 85 ° C.) was encountered at any stage in the battery manufacturing process (usually the coating process). I know that there is.

  In the battery of FIG. 1 (f), the resin exterior material side printing portion 12 is also discolored. Therefore, in this case, it can be estimated that an unexpected temperature (in this case, a temperature exceeding 85 ° C.) was encountered at the time of shipment or use after completion of the battery, and it can be understood that this is the cause of the malfunction.

  In the battery of FIG. 1 (d), the two temperature indicating portions are not discolored. Therefore, in this case, it is estimated that the encounter with the unexpected temperature is not the cause of the malfunction, and it is understood that there are other causes.

Therefore, according to the present embodiment, the following effects can be obtained.
(1) In the cylindrical lithium battery 1 according to this embodiment, the temperature indicating portions 11 and 12 made of temperature indicating ink whose color changes irreversibly when reaching a set temperature of 85 ° C. are used as the surface of the unit cell 2 and the exterior film. 5 on both surfaces. Here, the unit cell side temperature indicating portion 11 is provided in a process in the middle of the battery manufacturing stage, whereas the resin exterior material side temperature indicating portion 12 is provided after the battery is almost completed. Therefore, if it is the latter, it can react to the high temperature encountered in the stage after completion of battery manufacture, and if it is the former, it can react also to the high temperature encountered in the battery manufacturing stage. Therefore, if these two types of temperature indicating portions 11 and 12 are arranged in combination, and based on the change in color of these two temperature indicating portions 11 and 12, information regarding the temperature history from the time of manufacture of the battery to the time of use can be visually confirmed. It can be obtained objectively and sufficiently. Therefore, it can be set as the cylindrical lithium battery 1 which can investigate smoothly the cause when a malfunction arises. In particular, according to the cylindrical lithium battery 1 of the present embodiment, it is possible to estimate that the cause of the failure is one of the three patterns.

  (2) In the present embodiment, the temperature indicating ink is used as the temperature indicating material, and the printing units 11 and 12 are provided by printing using the temperature indicating ink. Therefore, when the printing units 11 and 12 are provided, it is sufficient to perform printing using the temperature indicating ink instead of the ink that is normally used. Therefore, there is no increase in the number of parts and the number of processes, and the cost is increased. It can be prevented in advance.

  (3) In this embodiment, the printing units 11 and 12 are printing units that also serve as manufacturing codes. The manufacturing code is normally printed on the battery. By using this as the print section printed with the temperature indicating ink, not only the product information related to the battery is presented, but also the temperature history from the time of battery manufacture to the time of use. It is possible to obtain information on Moreover, according to this structure, the information regarding the said temperature history can be obtained, without affecting the external appearance of a battery so much.

  In addition, you may change embodiment of this invention as follows.

  -In the cylindrical lithium battery 1 of the said embodiment, the resin exterior material side printing part 12 was piled up in the position right above the unit cell side printing part 11, and was arrange | positioned. Instead of this, for example, a cylindrical lithium battery 21 of another embodiment shown in FIG. 3 may be used. In the case of the cylindrical lithium battery 21, a rectangular transparent window portion 22 that allows the unit cell 2 to be partially visually recognized is formed on the exterior film 5. The transparent window portion 22 is formed, for example, by partially removing the printing layer on the exterior film 5. The unit cell side printing unit 11 is disposed at a position corresponding to the transparent window unit 22 on the surface of the unit cell 2. The size of the transparent window portion 22 is comparable to the size of the formation region of the unit cell side printing portion 11. In the exterior film 5, the resin exterior material side printing section 12 is disposed at a position different from the transparent window section 22, specifically at a position around the transparent window section 22.

  Therefore, according to this structure, by providing the transparent window part 22, the unit cell side printing part 11 can always be visually recognized. Therefore, when visually inspecting the unit cell-side printing unit 11, the unit cell-side printing unit 11 and the resin outer packaging material can be used without having to peel all or part of the exterior film 5 to expose the surface of the unit cell 2. Both side printing parts 12 can be visually recognized. Therefore, the information regarding the temperature history from the time of battery manufacture to the time of use can be easily confirmed.

  -In above-mentioned embodiment, although the unit cell side printing part 11 was provided in the outer peripheral surface 3a of the armored can 3, it is not limited to this, You may provide in another position. For example, in the cylindrical lithium battery 31 of another embodiment shown in FIG. 4, the unit cell is exposed to the portion exposed from the exterior film 5, that is, the outer peripheral portion of the upper end surface of the unit cell 2 (that is, the outer peripheral portion of the negative electrode terminal plate 4). A side printing unit 32 is provided. In addition, since the center part of the upper end surface of the unit cell 2 (that is, the center part of the negative electrode terminal plate 4) is a terminal contact part, it is not suitable for forming the unit cell side printing part 32. Therefore, even with this configuration, the unit cell-side printing unit 32 is always visible. Therefore, when visually inspecting the unit cell side printing part 32, it is not necessary to peel off part or all of the exterior film 5 to expose the surface of the unit cell 2 or to provide the transparent window part 22. In addition, both the unit cell side printing part 32 and the resin exterior material side printing part 12 are visible. Therefore, the information regarding the temperature history from the time of battery manufacture to the time of use can be easily confirmed.

  In the above embodiment, the electricity storage device of the present invention is embodied in a cylindrical lithium battery, but can be embodied in a cylindrical alkaline battery, and further embodied in a lithium ion battery, a lithium ion capacitor, or the like. be able to.

  -The electrical storage device of this invention may be embodied as an assembled battery produced by combining a plurality of batteries. For example, an assembled battery 41 is shown as another embodiment shown in FIG. The assembled battery 41 is basically configured by combining two cylindrical lithium batteries 1 manufactured by the method of the above embodiment. However, the unit cell-side printing unit 11 is disposed on the surface of the unit cell 2, whereas the resin exterior material-side printing unit 12 is not disposed on the surface of the exterior film 5. In addition, these two cylindrical lithium batteries 1 are covered with a heat-shrinkable exterior film 42 which is another resin exterior material in a state of being arranged in parallel. Furthermore, an exterior label 43, which is another resin exterior material, is stuck on the coated exterior film 42. On the surface of the exterior label 43, a resin exterior material side printing section 44 is provided which is printed with the temperature indicating ink described above. This resin exterior material side printing section 44 is a printing section that also serves as a manufacturing code, and is expressed by a character string “EEEEFFF” for the convenience of drawing creation.

  In the above embodiment, the printing unit that also serves as the manufacturing code is provided. However, a printing unit that is not related to the manufacturing code may be provided.

  In the above embodiment, the common temperature indicating ink is used in the first temperature indicating portion disposing step and the second temperature indicating portion disposing step, and the reaction temperature (set temperature) of the temperature indicating ink is 85 ° C. The reaction temperature may be changed. Further, by using different temperature indicating inks in the first temperature indicating portion disposing step and the second temperature indicating portion disposing step, the reaction temperature may be varied in both steps.

Next, the technical ideas grasped by the embodiment described above are listed below.
(1) An electricity storage device including a unit cell and a resin sheathing material that covers the unit cell, wherein the unit cell includes a temperature indicating portion made of a temperature indicating material whose color changes irreversibly when reaching a set temperature. An electricity storage device characterized by being provided on both the outer peripheral surface of the outer can and the surface of the resin outer casing.
(2) An electricity storage device including a unit cell and a resin sheathing material that covers the unit cell, wherein the unit cell includes a temperature indicating portion made of a temperature indicating material whose color changes irreversibly when reaching a set temperature. An electric storage device, characterized in that it is provided on both the outer peripheral surface of the resin and the surface of the resin sheathing material.

DESCRIPTION OF SYMBOLS 1, 21, 31 ... Cylindrical lithium battery as an electrical storage device 2 ... Unit cell 5, 42 ... Exterior film as resin exterior material 11 ... Unit cell side printing part 12, 44 ... Resin exterior as temperature indicating part on unit cell side Resin exterior material side printing part 22 as temperature indicating part on material side 22 ... Transparent window 41 ... Collective battery as electricity storage device 43 ... Exterior label as resin exterior material

Claims (5)

  An electricity storage device comprising a unit cell and a resin sheathing material that covers the unit cell, wherein a temperature indicating portion made of a temperature indicating material whose color changes irreversibly upon reaching a set temperature is provided on the surface of the unit cell and the resin. An electricity storage device characterized by being provided on both exterior materials.   The power storage device according to claim 1, wherein the temperature indicating material is temperature indicating ink, and the temperature indicating portion is a printed portion printed using the temperature indicating ink.   The power storage device according to claim 2, wherein the printing unit is a printing unit that also serves as a manufacturing code.   A transparent window portion that allows the unit cell to be visually recognized is formed in the resin sheathing material, and a temperature indicating portion on the unit cell side is disposed corresponding to the transparent window portion, and the transparent window portion is disposed in the resin sheathing material. 4. The electricity storage device according to claim 1, wherein a temperature indicating portion on the resin exterior material side is disposed at a position different from the portion. 5. It is a manufacturing method of the electrical storage device according to any one of claims 1 to 4,
A first temperature indicator arrangement step of providing the temperature indicator on the surface of the unit cell;
A short-time discharge step of discharging the unit cell,
A coating step of coating the unit cell with the resin sheathing; and
A method of manufacturing an electricity storage device, wherein the second temperature indicating portion disposing step of providing the temperature indicating portion on the resin sheathing material is performed in this order.

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