JP2005340144A - Secondary battery and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous secondary battery long in service life and capable of preventing an increase in internal pressure, a decrease in output capacity and an increase in the amount of gas generation even if stored for a long period. <P>SOLUTION: When the amount of intrusion of water into the battery is extremely small, a film satisfactory in quality cannot be formed on a surface of an electrode. This may cause an increase in internal pressure of the battery, a decrease in capacity or an increase in the amount of gas generation due to acceleration of the decomposition of an electrolyte as the battery is stored for a long period. Accordingly, the amount of intrusion of water into the battery is controlled and adjusted to an appropriate range to thereby prolong the service life of the battery. The secondary battery according to the present invention comprises a nonaqueous power generating element and an accommodating member that accommodates the power generating element in a sealed manner. Under a specified environment, the amount of intrusion of water into the accommodating member is 80 to 800 μg/(year Wh). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a secondary battery in which a power generation element is encapsulated with an exterior member such as a laminate film, and more particularly to a non-hydrolytic secondary battery such as a lithium secondary battery and a method for manufacturing the same.

  2. Description of the Related Art Non-hydrolytic secondary batteries such as lithium ion batteries, in which a power generation element is accommodated and sealed inside an exterior member such as a laminate film, are widely known. Such secondary batteries have begun to be widely used in mobile phones, notebook computers, electric vehicles, etc., and are lightweight and have high output, that is, high output per weight and long life. It is requested.

However, in such a non-hydrolytic secondary battery, when moisture enters the battery from the sealing part (joint part) of the exterior member, moisture decomposition gas is generated, and the battery expands or the capacity deteriorates. In some cases, the battery life cannot be maintained sufficiently long. Therefore, various measures for preventing the intrusion of moisture from the joint portion of the exterior member, such as bending the seal portion (joint portion), have been conventionally performed (for example, see Patent Document 1).
JP 2002-141030 A

  However, in such a conventional secondary battery, there has been a problem that even if moisture intrusion into the battery is strictly prevented, the battery life cannot be maintained sufficiently long.

  The present invention has been made in view of such problems, and an object thereof is to provide a non-hydrolytic secondary battery capable of maintaining a sufficiently long life and a method for manufacturing the same.

  The inventor of the present application, when the amount of moisture entering the battery becomes extremely small, a good quality film is not formed on the electrode surface, and the internal resistance of the battery increases or the capacity decreases due to long-term storage. Or, it has been found that the amount of gas generated increases due to the accelerated decomposition of the electrolyte, and the battery life can be extended by controlling and adjusting the amount of moisture entering the battery within an appropriate range. I found.

  Therefore, the secondary battery according to the present invention has a non-water-decomposable power generation element and a housing member that hermetically accommodates the non-water-decomposable power generation element in the interior thereof. The moisture intrusion amount is 80 to 800 μg / (year · Wh).

  In another secondary battery according to the present invention, a non-water-decomposable power generation element, a housing member that encapsulates the non-water-decomposable power generation element, and the power generation element are hermetically housed in the housing member. A resin joint that joins the housing member, and the resin joint has a moisture penetration amount controlled to a desired penetration amount by changing the aspect of the resin joint. .

  Preferably, the housing member is a laminate film having a metal layer, the resin joint portion is a joint portion obtained by joining the laminate film with a predetermined width, and the resin joint portion is a joint of the laminate film. By cutting away the portion, the amount of moisture intrusion into the housing member is increased, and the amount of infiltration is adjusted to a desired amount.

  Further, in the method for manufacturing a secondary battery according to the present invention, the power generation element is covered with an exterior member, and the housing member is joined with a resin material interposed so that the power generation element is hermetically accommodated by the exterior member, The amount of moisture permeation into the housing member is adjusted by cutting out the resin joint.

  Preferably, the water intrusion amount is adjusted so that the water intrusion amount into the housing member is 80 to 800 μg / (year · Wh).

  According to the present invention, it is possible to suppress an increase in internal resistance, a decrease in output capacity, an increase in gas generation, and the like due to long-term storage in a non-hydrolytic secondary battery, and a long-life secondary battery and its A manufacturing method can be provided.

  The secondary battery according to the present invention will be described with reference to FIGS.

Configuration of Secondary Battery First, the basic configuration of the secondary battery will be described with reference to FIG. 1 and FIG.
FIG. 1 is a plan view showing the overall configuration of the secondary battery 100, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG.

  The secondary battery 100 is a laminated battery having a flat plate shape and a thin shape as a whole. As shown in FIGS. 1 and 2, the secondary battery 100 includes n positive plates 101 (n is an integer), 2n separators 102, n + 1 negative plates 103, positive tabs 104, negative tabs 105, upper portions A laminate film (upper exterior member) 106, a lower laminate film (lower exterior member) 107, and an electrolyte solution (liquid electrolyte) (not shown) are included.

As shown in FIG. 2, the secondary battery 100 includes the negative electrode plate 103 and the positive electrode plate 101 with the negative electrode plate 103 being the outermost part at both upper and lower ends, and the separator 102 interposed between the negative electrode plate 103 and the positive electrode plate 101. It has the structure which laminated | stacked alternately.
The positive electrode plate 101, the separator 102, the negative electrode plate 103, and the electrolytic solution are particularly referred to as a power generation element 108.
The number n of positive electrode stacks is set so that a predetermined battery capacity is obtained.

  As shown in FIG. 2, the positive electrode plate 101 includes a positive electrode current collector 101a extending to the positive electrode tab 104, and positive electrode layers 101b and 101c formed on both main surfaces of the positive electrode current collector 101a, respectively. . The positive electrode plate 101 is prepared by dispersing a powder (electrode mixture) in which spinel lithium manganese oxide is mixed with graphite as a conductive agent and polyvinylidene fluoride (PVDF) as a binder in N-methyl-2-pyrrolidone (NMP). Then, the slurry is uniformly applied as positive electrode layers 101b and 101c on both surfaces of the positive electrode side current collector 101a formed of aluminum foil, and compressed to a predetermined density by a roll press, It was cut out to the size of.

  The negative electrode plate 103 includes a negative electrode side current collector 103a extending to the negative electrode tab 105, and negative electrode layers 103b and 103c formed on both main surfaces of the negative electrode side current collector 103a, respectively. The negative electrode plate 103 is a slurry in which a powder (electrode mixture) obtained by mixing graphite as a conductive agent and polyvinylidene fluoride (PVDF) as a binder is dispersed in N-methyl-2-pyrrolidone (NMP). The slurry is uniformly applied as negative electrode layers 103b and 103c on both surfaces of the negative electrode side current collector 103a formed of copper foil, and is compressed to a predetermined density by a roll press, and has a predetermined size. It was cut out and formed.

  The separator 102 prevents a short circuit between the positive electrode plate 101 and the negative electrode plate 103 described above, and may have a function of holding an electrolytic solution. This separator 102 is a microporous film made of polyolefin such as polyethylene (PE) or polypropylene (PP), for example. When an overcurrent flows, the pores of the layer are blocked by the heat generation and the current is cut off. It also has a function to

  The positive electrode plate 101 is welded to a positive electrode tab (positive electrode terminal) 104 serving as a positive electrode lead. Similarly, the negative electrode plate 103 is welded to a negative electrode tab (negative electrode terminal) 105 serving as a negative electrode lead. For example, aluminum Al is suitable for the positive electrode tab 104, and nickel Ni or copper Cu is suitable for the negative electrode tab 105, for example. In addition, in order to improve the connection reliability with an electrode tab, the area | region for welding which does not apply | coat an electrode mixture previously is provided in the collector of each electrode plate.

The power generation element 108 to which the positive electrode tab 104 and the negative electrode tab 105 are connected is encapsulated in two laminate films 106 and 107 and enclosed in an inside thereof together with an electrolyte solution (not shown).
As the laminate films 106 and 107, an aluminum laminate film is used. The film has a three-layer structure, and is a nylon layer, an aluminum layer, and a polypropylene layer from the outside in a state where it is formed in a battery case. There may be a PET layer outside the nylon layer. Further, a polyethylene layer may be formed instead of the polypropylene layer.

  Also, a polypropylene sheet having a thickness of about 50 to 100 μm is thermally fused to the positive electrode tab 104 and the negative electrode tab 105 in order to avoid electrical contact (short circuit) with the metal layer (aluminum layer) of the laminate films 106 and 107. Has been.

  When the power generation element 108 is accommodated in the laminate films 106 and 107, first, a convex portion (cup part) for accommodating the power generation element 108 is formed on at least one of the laminate films 106 and 107. The power generation element 108 is accommodated in Next, the upper laminating film 106 and the lower laminating film 107 are combined to enclose the power generation element 108, and in this state, a total of 3 sides, that is, 2 sides on the short side and 1 side on the long side are heat-sealed. And after inject | pouring predetermined amount electrolyte solution from an opening part, the one side which remains in the pressure-reduced state is heat-seal | fused.

Note that the electrolytic solution, used Bro propylene carbonate, ethylene carbonate, a solution obtained by dissolving LiPF ₆ as a supporting electrolyte in a mixed solvent of diethyl carbonate.

Example 1 and Example 2 and Performance Evaluation for Moisture Infiltration A relationship between the amount of moisture infiltration and performance in the secondary battery having the basic configuration as described above will be described with reference to FIGS.
Here, for the secondary batteries of five types (Examples 1 and 2 and Comparative Examples 1 to 3) in which the sizes of the laminate films 106 and 107, the width of the seal portion, the type and thickness of the resin layer, and the like were changed, Each storage environment was set, and the amount of moisture permeated during the storage period and the performance evaluation after storage were performed.

First, specifications and storage conditions of five types of secondary batteries of Examples 1 and 2 and Comparative Examples 1 to 3 will be described with reference to FIGS. 3 and 4.
FIG. 3 is a diagram for explaining the specifications of each secondary battery, and FIG. 4 is a chart showing the specifications and storage conditions of each secondary battery.
In addition, all the batteries of Examples 1 and 2 and Comparative Examples 1 to 3 are secondary batteries manufactured to have an output capacity of 11 Wh.

  In Example 1, the outer dimension of the laminate film (the outer dimension of the packaging material, see FIG. 3A) is length (long side length L) 250 mm × width (short side length W) 155 mm. Both the short side and long side seal widths (see FIG. 3B) are 10 mm, the thickness of the heat-sealing resin layer (the distance between the aluminum layers in the two laminated films 106 and 107, FIG. B) is a secondary battery of 40 μm. A secondary battery having such a specification was manufactured at a temperature of 30 ° C. and a humidity of 55% R.D. H. Stored for 1 year.

  Example 2 is a secondary battery in which the outer dimensions of the laminate film are 236 mm long × 138 mm wide, both the short side and the long side have a seal width of 3 mm, and the thickness of the heat-sealing resin layer is 200 μm. is there. A secondary battery having such a specification was manufactured at a temperature of 30 ° C. and a humidity of 95% R.D. H. Stored for 1 year.

  In Comparative Example 1, the outer dimensions of the laminate film are 250 mm long × 155 mm wide as in Example 1, and both the short side and the long side have a seal width of 10 mm. This is a secondary battery of 40 μm, which is half that of the first embodiment. The secondary battery having such a specification was stored in a dry environment at a temperature of 30 ° C. and a dew point of −40 ° C. for one year.

  In Comparative Example 2, the outer dimensions of the laminate film are 236 mm long × 138 mm wide as in Example 2, the short side and long side seal widths are both 3 mm, and the thickness of the heat-sealing resin layer is The secondary battery is sealed to 200 μm. However, in Comparative Example 2, as a material of the heat-sealing resin layer, a material B having a higher water permeability than the material of Example 2 (Material A) (compared with the material A used in Example 2 alone) A secondary battery using a material having a water permeability of 2 to 3 times. This secondary battery was manufactured at a temperature of 30 ° C. and a humidity of 95% R.D. H. Stored for 1 year.

  In Comparative Example 3, the outer dimensions of the laminate film are 236 mm long × 138 mm wide as in Example 2, the short side and long side seal widths are both 3 mm, and the thickness of the heat-sealing resin layer is The secondary battery is sealed to 200 μm. However, in Comparative Example 3, as the laminate films 106 and 107, a secondary battery using a laminate film having extremely high moisture permeability using a hydrophilic resin adhesive for bonding the heat fusion resin layer and the aluminum layer. It is. In other words, as a material of the heat-sealing resin layer disposed between the aluminum layers in the two laminate films 106 and 107, a secondary material using a material C having higher moisture permeability than the material of Comparative Example 2 (material B). It is a battery. This secondary battery was manufactured at a temperature of 30 ° C. and a humidity of 95% R.D. H. Stored for 1 year.

The results of performance evaluation when the secondary batteries according to Example 1, Example 2, and Comparative Examples 1 to 3 are stored under the above-described conditions are shown in FIGS. The evaluation was performed with respect to the amount of moisture permeating into the battery after storage, the rate of increase in internal resistance, the capacity retention rate, and the amount of swelling.
The amount of moisture permeation was measured using a dummy battery manufactured by injecting only a solvent that does not dissolve LiPF ₆ as a supporting salt in the electrolyte. This is because if LiPF ₆ is present in the electrolyte solution, the moisture reacts with the LiPF ₆ and is consumed, so that the amount of moisture that has entered cannot be measured accurately.

  As shown in FIG. 5, the amount of moisture permeation (μg / year) per output capacity (Wh) increases in the order of Comparative Example 1 <Example 1 <Example 2 <Comparative Example 2 <Comparative Example 3.

  On the other hand, as shown in FIGS. 5 and 6, the increase rate of the internal resistance after storage is substantially the same in Comparative Example 1 and Example 1 in which the water intrusion amount is about 80 μg / year · Wh. As the moisture intrusion amount exceeds 80 μg / year · Wh, that is, in the order of Example 2, Comparative Example 2, and Comparative Example 3, there is a tendency to gradually decrease.

  As shown in FIG. 5 and FIG. 7, the retention rate of the battery capacity after storage is almost the same in Comparative Example 1 and Example 1 up to about 80 μg / year · Wh. Is higher than 80 μg / year · Wh, that is, in the order of Example 2, Comparative Example 2, and Comparative Example 3, there is a tendency to gradually increase.

  Further, the volume increase rate after storage (battery amount of the battery due to gas generation inside the battery) is as shown in FIG. 5 and FIG. In Example 3, it is rapidly increased. On the other hand, when the water intrusion amount is 80 μg / year · Wh or less, the volume gradually increases (the volume increase rate increases) in the order of Example 1 and Example 2 in which the water intrusion amount decreases. It is done.

  Summarizing the above evaluation results, as shown in FIG. 6 and FIG. 7, as the water intrusion amount increases from about 80 μg / year · Wh, the internal resistance increase rate decreases and the output capacity maintenance rate also increases. Therefore, it can be said that battery deterioration is suppressed. However, as shown in FIG. 8, when the water intrusion amount exceeds about 800 μg / year · Wh, the battery volume increases rapidly, which is not preferable.

  The reason why the capacity deterioration and the internal resistance increase rate are suppressed as the amount of moisture intrusion increases, as shown in FIGS. 9B and 9C, the self-discharge amount of the battery increases due to the decomposition of the intruded moisture. For this reason, an effect of lowering the charged state and voltage of the battery during storage can be considered.

Further, as shown in FIGS. 9B and 9C, a film that suppresses the decomposition of the electrolytic solution is formed on the electrode surface, and this film is locally destroyed during storage. Is re-formed by the reaction of the solvent of the electrolytic solution. If there is not enough moisture during the re-formation of the film, as shown in FIG. 9A, a thick film is formed and the internal resistance is increased, or a non-uniform film is formed and the electrolyte solution It is thought that it will be decomposed.
However, since the amount of moisture infiltrated is sufficient and sufficient moisture exists during film re-formation, a uniform thin film is formed, preventing the formation of such thick or non-uniform films, and internal resistance. And the decomposition of the electrolyte can be suppressed. This can also be considered as one of the reasons that the capacity deterioration and the internal resistance increase rate are suppressed as the amount of moisture intrusion increases.

The reason why the battery volume is increasing in a region where the amount of moisture permeation is small is that the film on the electrode surface becomes non-uniform as shown in FIG. It is considered that a decomposition gas of the electrolyte is generated in
In addition, as a reason why the battery volume increases in a region where the amount of moisture permeation is large, as shown in FIG. 9C, it is considered that excessive moisture decomposition gas that is not consumed in film formation is generated.

  From the above evaluation results, by adjusting the amount of moisture intrusion into the battery within an appropriate range, specifically, a thin uniform film that suppresses the decomposition of the electrolyte on the electrode surface as shown in FIG. By allowing an appropriate amount of moisture to enter the battery, it is possible to suppress the deterioration of the capacity of the secondary battery, the increase in internal resistance, and the expansion of the volume, thereby achieving a long battery life. From the results shown in FIGS. 5 to 8, it is preferable to adjust the moisture intrusion amount to a range of 80 to 800 μg / year per battery output capacity (Wh).

Method of adjusting the moisture penetration weight Next, a method of manufacturing a suitable moisture penetration amount of the secondary battery as described above, in other words, how to control the water penetration amount of the secondary battery to a desired amount, FIG. 10 A description will be given with reference to FIG.

  Laminate films 106 and 107 used as exterior members have a metal layer such as aluminum as described above. If the thickness of the aluminum layer is 20 μm or more after the laminate film is shaped into a cup, the aluminum layer It can be said that there is no water permeation through the water. Therefore, the moisture enters from the heat-sealing resin layer of the seal portion where the two laminate films 106 and 107 are bonded.

The amount of moisture intrusion from the seal portion varies mainly due to the following first to fourth factors.
The first factor is physical properties such as moisture permeability of the heat-sealing resin layer of the laminate film. In Example 2, Comparative Example 2 and Comparative Example 3 shown in FIG. 4, the material of the resin layer is changed. As shown in FIG. 5, the higher the moisture permeability, the greater the amount of moisture penetration. ing.
The second factor is the cross-sectional area of the moisture permeable surface defined by the thickness of the heat-sealing resin layer (distance between the aluminum metal layers after sealing) and the length of the seal portion (see FIG. 3B). . When the thickness of the resin layer is reduced and the length of the seal portion is shortened, the amount of moisture intrusion decreases.

The third factor is the seal width (moisture permeation distance) of the seal portion (see FIG. 3B). When the seal width is narrowed, the moisture penetration amount increases, and when the seal width is widened, the moisture penetration amount decreases.
The fourth factor is the usage environment of the battery. The lower the temperature and the lower the water vapor pressure, the lower the water intrusion amount.

  The amount of water intrusion into the secondary battery varies mainly due to such factors. Therefore, it is practically difficult to adjust the water intrusion amount to a certain range in any use environment having different temperatures and humidity in a secondary battery having a specific specification. Therefore, as a method of realistically adjusting the amount of water penetration of the secondary battery, a secondary battery that can easily change the specifications of the secondary battery according to the climate, environment, etc. of the region to be used is manufactured. It is effective to leave

  As the method, it is also possible to adjust the length of the seal portion around the laminate film or to adjust the thickness of the resin layer. However, in order to do so, it is necessary to use a laminate film with a different resin layer thickness depending on the battery usage environment, or to change the sealing conditions during battery manufacturing, and therefore, it is necessary to change the battery manufacturing process. It is difficult to use unless the resin layer thickness is measured.

Therefore, in the secondary battery according to the present invention, an appropriate thickness of the heat-sealing resin layer is selected according to the outer dimensions (the length of the seal portion) defined by the battery installation location, usage pattern, and the like. A secondary battery is manufactured in advance with a seal width such that the moisture intrusion amount is 800 μg / year · Wh or less in an assumed environment (high temperature, high humidity, etc.) with the largest amount of moisture intrusion.
For the battery thus manufactured, the seal portion is cut and the width thereof is adjusted so that the moisture intrusion amount is 80 μg / year · Wh or more according to the use environment of the battery.

This will be specifically described with reference to FIGS. 10 (A) and 10 (B).
For example, when used in an environment where the water vapor pressure is low at a relatively low temperature, and the moisture intrusion amount is not 80 μg / year · Wh or more in the production state, as shown in FIG. Cut off the seal and narrow the seal width. By doing so, the amount of moisture intrusion can be increased, and the appropriate range, that is, 80 μg / year · Wh or more can be easily achieved.

On the other hand, when used in an environment where the water vapor pressure is high at a relatively high temperature, the water intrusion amount is considered to be 80 μg / year · Wh or more in the state at the time of manufacture. In addition, the maximum amount of moisture intrusion should be suppressed to 800 μg / year · Wh or less due to manufacturing conditions. Therefore, as shown in FIG. 10B, the seal portion may be used as it is.
By adjusting the amount of water intrusion in this way, it is possible to easily manufacture a secondary battery with a desired amount of water intrusion without significantly changing the battery manufacturing process or sacrificing productivity. Can do.

A specific example in which the water intrusion amount of the secondary battery is adjusted by such a method, and an evaluation result of the water intrusion amount in each example will be described with reference to FIG.
First, specifications and storage conditions (use environment) of each embodiment will be described.

  In Example 3, the outer dimensions of the laminate film are 236 mm long × 145 mm wide, the seal width on the short side is 5 mm, the seal width on the long side is 3 mm, and the thickness of the heat-sealing resin layer is 120 μm. A secondary battery manufactured as described above. A secondary battery having such a specification was manufactured at a temperature of 15 ° C. and a humidity of 70% R.D. H. Stored for 1 year.

  In Example 4, a secondary battery having the same specifications as in Example 3 was obtained by using a temperature of 25 ° C. and a humidity of 90% R.D. H. Stored for 1 year.

  Example 5 is a secondary battery in which the outer dimension of the laminate film is 250 mm long × 145 mm wide and the seal width on the long side is 10 mm with respect to the secondary battery 100 of Example 3. The seal width 5 mm on the short side and the thickness 120 μm of the heat-sealing resin layer are the same as those in Example 3. Then, the manufactured secondary battery was subjected to a temperature of 20 ° C. and a humidity of 70% R.D. H. Stored for 1 year.

  In Example 6, a secondary battery having the same specifications as in Example 5 was obtained by using a temperature of 30 ° C. and a humidity of 90% R.D. H. Stored for 1 year.

  Example 7 is different from the secondary battery 100 of Example 1 in that the size of the positive electrode tab 104 is 522 mm long × 310 mm wide, the size of the negative electrode tab 105 is 524 mm long × 312 mm wide, and the outer dimensions of the laminate film. Is a secondary battery manufactured in such a manner that the seal width on the short side is 5 mm, the seal width on the long side is 5 mm, and the thickness of the heat-sealing resin layer is 80 μm. A secondary battery having such a specification was manufactured at a temperature of 15 ° C. and a humidity of 70% R.D. H. Stored for 1 year.

  Example 8 is a secondary battery 100 manufactured by setting the outer dimensions of the laminate film to a length of 550 mm × width of 330 mm and the long side seal width of 10 mm with respect to the secondary battery 100 of Example 7. The seal width of 5 mm on the short side and the thickness of the heat-sealing resin layer of 80 μm are the same as in Example 7. A secondary battery having such a specification was manufactured at a temperature of 15 ° C. and a humidity of 70% R.D. H. Stored for 1 year.

The water intrusion amounts after storage in Examples 3 to 8 are as shown in FIG.
In the secondary batteries of Examples 3 and 4, the seal width on the long side of the secondary batteries of Examples 5 and 6 is cut from 10 mm to 3 mm.
The batteries used in Examples 5 and 6 have a temperature of 20 degrees and a humidity of 70% R.D. H. And a temperature of 30 ° C. and a humidity of 90%. H. In this environment, the moisture intrusion amount is in the range of 80 to 800 μg / year · Wh. By cutting the long side seal portion of this battery to 7 mm by cutting 7 mm, as shown in Example 3 and Example 4, the temperature is 15 ° C. and the humidity is 70% R.D. H. And a temperature of 25 ° C. and a humidity of 90% H. The water intrusion amount is within the range of 80 to 800 μg / year · Wh in the environment of

  Example 7 and Example 8 have the same battery capacity as the batteries in Examples 3 to 6, but the size of the positive electrode tab 104 and the negative electrode tab 105 is increased, and the number of stacked electrodes is reduced to about 1/6. Thus, the outer dimensions of the battery are increased. In Example 7 and Example 8, since the seal length of the outer member outer week portion is longer than in Examples 3 to 6, the thickness of the resin layer is reduced from 120 μm to 80 μm. Also in this case, by changing the seal width of the long side from 10 mm to 5 mm, the temperature is 15 ° C. and the humidity is 70% R.D. H. And a temperature of 30 ° C. and a humidity of 90% R.D. H. In each environment, it was possible to adjust to an appropriate amount of moisture penetration.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment includes all design changes and equivalents belonging to the technical scope of the present invention.

FIG. 1 is a plan view showing an overall configuration of a secondary battery according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is a diagram for explaining the specifications of the secondary batteries of Examples and Comparative Examples. FIG. 4 is a diagram showing the specifications of the secondary batteries of Examples and Comparative Examples and the conditions of the storage experiment. FIG. 5 is a diagram showing results of storage experiments of secondary batteries of Examples and Comparative Examples. FIG. 6 is a diagram showing the relationship between the amount of moisture permeation and the rate of increase in internal resistance based on secondary battery storage experiments. FIG. 7 is a diagram showing the relationship between the amount of moisture permeation and the volume retention rate based on the secondary battery storage experiment. FIG. 8 is a diagram showing the relationship between the water intrusion amount and the volume increase rate based on the storage experiment of the secondary battery. FIG. 9 is a diagram schematically showing the state in the secondary battery into which moisture has entered, for each moisture that has entered. FIG. 10 is a diagram for explaining a method of adjusting the moisture intrusion amount. FIG. 11 is a diagram showing the specifications and experimental results of the secondary battery of each example of the experiment for adjusting the moisture intrusion amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Secondary battery 101 ... Positive electrode plate 102 ... Separator 103 ... Negative electrode plate 104 ... Positive electrode tab 105 ... Negative electrode tab 106 ... Upper laminate film 107 ... Lower laminate film 108 ... Electric power generation element

Claims (5)

Non-hydrolytic power generation elements,
A housing member for hermetically housing the non-water-decomposable power generation element inside,
A secondary battery characterized in that, under a predetermined environment, the amount of moisture permeating into the housing member is 80 to 800 μg / (year · Wh). Non-hydrolytic power generation elements,
A housing member encapsulating the non-hydrolyzable power generation element;
A resin joint that joins the housing member so that the power generating element is hermetically housed in the housing member, and the amount of moisture intrusion into the housing member is reduced by changing the aspect of the resin joint. A secondary battery having a resin bonding portion controlled to have a desired penetration amount. The housing member is a laminate film having a metal layer,
The resin joint is a joint obtained by joining the laminate film with a predetermined width,
The resin joint portion is formed so as to increase the moisture intrusion amount into the housing member by adjusting the laminate film film by cutting away the joint portion of the laminate film. The secondary battery according to claim 2. The power generation element is covered with an exterior member,
Joining the housing member with a resin material interposed so that the power generation element is hermetically housed by the exterior member,
A method for manufacturing a secondary battery, comprising: cutting out the resin joint portion to increase a water intrusion amount into the housing member and adjusting the water intrusion amount.   5. The method of manufacturing a secondary battery according to claim 4, wherein the moisture intrusion amount is adjusted so that the moisture intrusion amount into the housing member is 80 to 800 μg / (year · Wh). .

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