Patent Publication Number: US-2023163362-A1

Title: Battery Production Method, Battery Production Apparatus, and Battery

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This nonprovisional application claims priority to Japanese Patent Application No. 2021-189581 filed on Nov. 22, 2021, with the Japan Patent Office, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a battery production method, a battery production apparatus, and a battery. 
     Description of the Background Art 
     Japanese Patent Laying-Open No. 7-266420 discloses an ultrasonic welding apparatus including a second ultrasonic horn portion that outputs an ultrasonic wave having a frequency different from a vibration frequency of a first ultrasonic horn portion. 
     SUMMARY 
     A laminate film is used as a casing of a battery. Such a casing composed of a laminate film is referred to as a “laminated casing”. A battery including the laminated casing is referred to as a “laminate-type battery”. 
     For example, an electrode assembly (power generation element) is accommodated in the laminated casing. At the peripheral edge of the laminated casing, the laminated casing is welded, thereby forming a sealed portion. 
     Generally, the sealed portion is formed by heat sealing. That is, the sealed portion is formed by pressing a heat bar against the laminated casing. When ultrasonic welding is employed instead of the heat sealing, it is expected to improve productivity, for example. However, the ultrasonic welding tends to provide welding strength lower than that in the heat sealing. 
     It is an object of the present disclosure to improve welding strength in ultrasonic welding. 
     Hereinafter, the technical configurations, functions and effects of the present disclosure will be described. However, a mechanism of function in the present specification include presumption. The mechanism of function does not limit the technical scope of the present disclosure. 
     1. A battery production method includes the following (a) to (c). 
     (a) An electrode assembly is accommodated in a laminated casing. 
     (b) A pressure-applied portion is formed by sandwiching at least a portion of a peripheral edge of the laminated casing between a first horn and a second horn. 
     (c) A sealed portion is formed by applying ultrasonic vibration from each of the first horn and the second horn to the pressure-applied portion. 
     The first horn has a first vibration direction. The second horn has a second vibration direction. 
     The first vibration direction is parallel to a thickness direction of the laminated casing. The second vibration direction is non-parallel to the first vibration direction. 
     Generally, the vibration direction of a horn in ultrasonic welding is a direction perpendicular to a joining surface (processing target). When forming a sealed portion in a laminated casing, the vibration direction of the horn is parallel to the thickness direction of the laminated casing. 
     In the battery production method of the present disclosure, the first horn and the second horn are used. The first horn is vibrated in parallel with the thickness direction of the laminated casing. It is expected to melt a resin by the vibration of the first horn. The second horn is vibrated in a direction different from that of the first horn. With the vibration of the second horn, the molten resin can be stirred. Due to the vibrations in the two directions, it is expected to mix the resin in a wide range at the joining interface. With the mixing of the resin, it is expected to improve the welding strength. 
     2. The second vibration direction may be orthogonal to the first vibration direction. 
     Since the vibration direction of the second horn is orthogonal to the vibration direction of the first horn, it is expected to improve efficiency of stirring of the resin and the like, for example. 
     3. The first horn may have an amplitude twice or less as large as a thickness of the laminated casing. 
     Since the amplitude of the first horn is twice or less as large as the thickness of the laminated casing (laminate film), damage to the laminate film is expected to be reduced. 
     4. The second horn may be vibrated in synchronism with the first horn. 
     The expression “in synchronism” means that the position of the second horn is specified when the position of the first horn is specified during the vibration, because the second horn is vibrated in conjunction with the first horn. For example, when the first horn is located at the end of the vibration, the second horn may be vibrated to be located at the center of the vibration. Since the second horn is vibrated in synchronism with the first horn, welding strength is expected to be improved, for example. 
     5. At least one of the first horn and the second horn may include a knurled portion. The knurled portion may be in contact with the laminated casing. 
     The “knurled portion” represents a portion having been through a knurling process. By bringing the knurled portion into contact with the laminated casing, it is expected to improve efficiency of melting of the resin, efficiency of stirring of the resin, and the like, for example. 
     6. The sealed portion may include a first region and a second region. In the first region, portions of the laminated casing are welded to each other. In the second region, an electrode tab is sandwiched between the portions of the laminated casing. At least one of the first horn and the second horn may include a first portion and a second portion. The first portion forms the first region. The second portion forms the second region. The second portion is located backward with respect to the first portion in the thickness direction of the laminated casing. 
     The laminate-type battery can include the electrode tab. The electrode tab is joined to the electrode assembly. The electrode tab is led out from the inside to outside of the laminated casing. For example, it is required to perform ultrasonic welding with the electrode tab being sandwiched. When the ultrasonic welding is performed with the electrode tab sandwiched, a step is formed by the electrode tab, with the result that pressure applying force may become large locally. Since the portion of the horn corresponding to the electrode tab is located backward, it is expected to attain a small pressure difference between the region (second region) corresponding to the electrode tab and the other region (the first region). Thus, it is expected to reduce a difference in welding strength between the first region and the second region, for example. 
     7. A battery production apparatus forms a sealed portion at a peripheral edge of a laminated casing in which an electrode assembly is accommodated. The battery production apparatus includes a first horn, a second horn, a pressure applying apparatus, a first ultrasonic wave generating apparatus, and a second ultrasonic wave generating apparatus. The first horn and the second horn are configured to sandwich at least a portion of the peripheral edge of the laminated casing between the first horn and the second horn. The pressure applying apparatus is configured to apply pressure applying force to at least one of the first horn and the second horn. The first ultrasonic wave generating apparatus is configured to apply, to the first horn, ultrasonic vibration in a first vibration direction. The second ultrasonic wave generating apparatus is configured to apply, to the second horn, ultrasonic vibration in a second vibration direction. The first vibration direction is parallel to a thickness direction of the laminated casing. The second vibration direction is non-parallel to the first vibration direction. 
     In the battery production apparatus of “7”, the battery production method of “1” can be performed. 
     8. In the battery production apparatus, the second vibration direction may be orthogonal to the first vibration direction. 
     In the battery production apparatus of “8”, the battery production method of “2” can be performed. 
     9. In the battery production apparatus, at least one of the first horn and the second horn may include a knurled portion. The knurled portion may be configured to be in contact with the laminated casing. 
     In the battery production apparatus of “9”, the battery production method of “5” can be performed. 
     10. The sealed portion may include a first region and a second region. In the first region, portions of the laminated casing are welded to each other. In the second region, an electrode tab is sandwiched between the portions of the laminated casing. 
     In the battery production apparatus, at least one of the first horn and the second horn may include a first portion and a second portion. The first portion is configured to form the first region. The second portion is configured to form the second region. The second portion is located backward with respect to the first portion in the thickness direction of the laminated casing. 
     In the battery production apparatus of “10”, the battery production method of “6” can be performed. 
     11. The battery includes a laminated casing and an electrode assembly. The laminated casing accommodates the electrode assembly. The laminated casing includes a sealed portion at at least a portion of a peripheral edge of the laminated casing. The sealed portion includes a first surface and a second surface. The second surface is a surface opposite to the first surface. A processing mark is formed on the first surface or the second surface. The processing mark extends in a direction orthogonal to a thickness direction of the laminated casing. 
     It is considered that the vibration provided by the first horn (vibration in the thickness direction) is less likely to form a processing mark (scratch) on an outer surface of the laminated casing. The second horn is vibrated in non-parallel with the first horn. The vibration provided by the second horn can form a processing mark on the outer surface of the laminated casing. The processing mark can be formed along the second vibration direction (vibration direction of the second horn). 
     The foregoing and other objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of the present disclosure when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic flowchart of a battery production method according to the present embodiment. 
         FIG.  2    is a schematic top view of a battery according to the present embodiment. 
         FIG.  3    is a first conceptual diagram showing exemplary first horn and second horn according to the present embodiment. 
         FIG.  4    is a second conceptual diagram showing the exemplary first horn and second horn according to the present embodiment. 
         FIG.  5    is a conceptual diagram showing a battery production apparatus according to the present embodiment. 
         FIG.  6    is a conceptual diagram of the battery according to the present embodiment. 
         FIG.  7    is a conceptual diagram of a battery according to a reference embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     &lt;Definitions of Terms, etc.&gt; 
     Hereinafter, an embodiment (hereinafter, simply referred to as “the present embodiment”) of the present disclosure will be described. It should be noted that the present embodiment does not limit the technical scope of the present disclosure. 
     In the present specification, the terms “comprise”, “include”, and “have” as well as their variants (such as “be composed of”) are open-end expressions. Each of the open-end expressions may or may not further include additional element(s). The expression “consist of” is a closed expression. It should be noted that even the closed expression does not exclude impurit(ies) that are involved in normal cases, as well as additional element(s) irrelevant to the technology of the present disclosure. The expression “consist essentially of” is a semi-closed expression. The semi-closed expression permits addition of element(s) that do not essentially affect basic and novel characteristics of the technology of the present disclosure. 
     In the present specification, each of the words “may” and “can” is used in a permissible sense, i.e., “have a possibility to do”, rather than in a mandatory sense, i.e., “must do”. In the present specification, elements represented by singular forms may include plural forms as well, unless otherwise stated particularly. 
     In a method described in the present specification, an order of execution of a plurality of steps, operations, actions or the like is not limited to the described order unless otherwise stated particularly. For example, a plurality of steps may be performed simultaneously. For example, a plurality of steps may be performed earlier or later. 
     Geometric terms in the present specification (for example, the terms such as “parallel”, “perpendicular”, and “orthogonal”) should not be interpreted in a strict sense. For example, the term “parallel” may be deviated to some extent from the strict definition of the term “parallel”. The geometric terms in the present specification can include, for example, a tolerance, an error, and the like in terms of design, operation, manufacturing, and the like. A dimensional relation in each of the figures may not coincide with an actual dimensional relation. In order to facilitate understanding of the technology of the present disclosure, the dimensional relation (length, width, thickness, or the like) in each figure may be changed. Further, part of configurations may be omitted. 
     In the present specification, the expression “when viewed in a plan view” indicates to view an object (for example, a laminated casing, a battery, or the like) along a line of sight parallel to the thickness direction of the object. The plan view can be shown in the form of a top view or a bottom view, for example. 
     In the present specification, a numerical range such as “m to n %” includes the lower and upper limit values unless otherwise stated particularly. That is, “m to n %” indicates a numeric value range of “more than or equal to m % and less than or equal to n %”. Moreover, the expression “more than or equal to m % and less than or equal to n %” includes “more than m % and less than n %”. Further, a numerical value freely selected from the numerical range may be employed as a new lower or upper limit value. For example, a new numerical range may be set by freely combining a numerical value described in the numerical range with a numerical value described in another portion of the present specification, table or figure. 
     In the present specification, all the numerical values are modified by the term “about”. The term “about” can mean, for example, ±5%, ±3%, ±1%, or the like. All the numerical values can be approximate values that can be changed depending on a manner of use of the technology of the present disclosure. All the numerical values can be indicated as significant figures. A measurement value can be an average value in multiple measurements. The number of measurements may be more than or equal to 3, more than or equal to 5, or more than or equal to 10. In general, as the number of measurements is larger, the reliability of the average value is expected to become higher. The measurement value can be rounded off based on the number of digits of the significant figure. The measurement value can include an error resulting from a detection limit of a measurement apparatus or the like, for example. 
     The present embodiment can be applied to any battery system as long as a laminated casing is used. The present embodiment may be applied to, for example, a lithium ion battery or the like. The lithium ion battery may include a liquid electrolyte, a gel electrolyte, or a solid electrolyte. The present embodiment may be applied to, for example, a nickel-metal hydride battery or the like. The nickel-metal hydride battery may be of a bipolar type, for example. 
     &lt;Battery Production Method&gt; 
       FIG.  1    is a schematic flowchart of a battery production method according to the present embodiment. Hereinafter, the expression “battery production method according to the present embodiment” can be simply referred to as “the present production method”. The present production method includes “(a) accommodation”, “(b) application of pressure”, and “(c) ultrasonic vibration”. It should be noted that the order in  FIG.  1    is for the sake of convenience. For example, “(b) application of pressure” and “(c) ultrasonic vibration” may be performed substantially simultaneously. 
     &lt;&lt;(a) Accommodation&gt;&gt; 
       FIG.  2    is a schematic top view of a battery according to the present embodiment. Hereinafter, the expression “battery according to the present embodiment” can be simply referred to as “the present battery”. The present production method includes accommodating an electrode assembly  120  in a laminated casing  110 . 
     Laminated casing  110  includes a laminate film. Laminated casing  110  is in the form of a pouch. Laminated casing  110  may consist of one laminate film. Laminated casing  110  may include a plurality of laminate films. 
     Laminated casing  110  may include, for example, an accommodation portion  119 . Accommodation portion  119  may be, for example, a recess in the form of a tray. Accommodation portion  119  may extend along the outer shape of electrode assembly  120 . Electrode assembly  120  is accommodated in accommodation portion  119 . Further, for example, an electrolyte solution may be introduced into accommodation portion  119 . 
     Portions of the laminate film are stacked on each other at the periphery edge of accommodation portion  119 . The laminate film includes a resin layer. At the peripheral edge of accommodation portion  119 , a contact surface between portions of the resin layer are formed. 
     &lt;&lt;(b) Application of Pressure&gt;&gt; 
       FIG.  3    is a first conceptual view showing exemplary first horn and second horn according to the present embodiment. The present production method includes forming a pressure-applied portion by sandwiching at least a portion of the peripheral edge of laminated casing  110  between a first horn  211  and a second horn  212 . 
     The pressure-applied portion is formed on the contact surface between the portions of the resin layer. The pressure-applied portion represents a portion to which pressure is applied. The magnitude of the pressure may be appropriately adjusted to obtain a desired welding strength. 
     Each of first horn  211  and second horn  212  can transmit ultrasonic vibration to a workpiece. Each of first horn  211  and second horn  212  may be composed of, for example, an aluminum (Al) alloy, a titanium (Ti) alloy, or the like. At least one of first horn  211  and second horn  212  may include a knurled portion  3 . On a surface of knurled portion  3 , a fine recess/projection pattern is engraved. The recess/projection pattern may be, for example, straight or cross. During ultrasonic vibration, knurled portion  3  can be in contact with laminated casing  110 . Since the vibration is transmitted by knurled portion  3 , it is expected to improve efficiency of melting of the resin, efficiency of stirring of the resin, and the like, for example. 
     &lt;&lt;(c) Ultrasonic Vibration&gt;&gt; 
     The present production method includes forming a sealed portion  115  by applying ultrasonic vibration from each of first horn  211  and second horn  212  to the pressure-applied portion. With the formation of sealed portion  115 , the present battery  100  can be completed. 
     First horn  211  has a first vibration direction V 1  (see  FIG.  3   ). Second horn  212  has a second vibration direction V 2 . First vibration direction V 1  is parallel to the thickness direction (Z axis direction in  FIG.  2   ) of laminated casing  110 . Second vibration direction V 2  is non-parallel to first vibration direction V 1 . With the vibration of first horn  211 , the resin at the pressure-applied portion is melted. With the vibration of second horn  212 , the molten resin is stirred. Due to the vibrations in the two directions, it is expected to mix the resin in a wide range at the joining interface. With the mixing of the resin, it is expected to improve the welding strength. 
     The amplitude of the vibration of first horn  211  may be, for example, twice or less as large as the thickness of laminated casing  110 . Thus, damage to laminated casing  110  can be reduced, for example. For example, the amplitude of first horn  211  may be 0.5 to 1.8 times or 1 to 1.5 times as large as the thickness of laminated casing  110 . 
     Second vibration direction V 2  may be any direction as long as second vibration direction V 2  is non-parallel to first vibration direction V 1 . An angle formed by second vibration direction V 2  and first vibration direction V 1  may be, for example, 30 to 150°. Second vibration direction V 2  may be orthogonal to first vibration direction V 1 , for example. When second vibration direction V 2  is orthogonal to first vibration direction V 1 , it is expected to improve the efficiency of stirring of the resin and the like, for example. When second vibration direction V 2  is orthogonal to first vibration direction V 1 , second vibration direction V 2  may be any direction in a plane orthogonal to first vibration direction V 1 . Second vibration direction V 2  may be, for example, parallel to the Y axis direction in  FIG.  2   , or may be parallel to the X axis direction in  FIG.  2   . 
     For example, each of first horn  211  and second horn  212  may be vibrated independently. For example, second horn  212  may be vibrated in synchronism with first horn  211 . For example, when first horn  211  is located at the end of the vibration, second horn  212  may be vibrated to be located at the center of the vibration. For example, when first horn  211  is located at the center of the vibration, second horn  212  may be vibrated to be located at the end of the vibration. Since second horn  212  is vibrated in synchronism with first horn  211 , the welding strength is expected to be improved, for example. 
     Each of the tips of first horn  211  and second horn  212  may be in the form of a frame. During the ultrasonic vibration, the tips of first horn  211  and second horn  212  may surround electrode assembly  120  when viewed in a plan view. First horn  211  and second horn  212  may press sealed portion  115  uniformly, for example. For example, pressure applying force may be adjusted in accordance with the recesses/projections (steps) of sealed portion  115 . For example, at a portion corresponding to an electrode tab  130 , the pressure applying force tends to be locally large. Also, the welding strength may be varied due to the variation in the pressure applying force. 
       FIG.  4    is a second conceptual diagram showing the exemplary first horn and second horn according to the present embodiment. Sealed portion  115  may include a first region R 1  and a second region R 2 . In first region R 1 , portions of laminated casing  110  are welded to each other. In second region R 2 , electrode tab  130  is sandwiched between the portions of laminated casing  110 . A tab film  140  may be interposed between electrode tab  130  and laminated casing  110 . 
     First horn  211  may include, for example, a first portion P 1  and a second portion P 2 . First portion P 1  forms first region R 1 . Second portion P 2  forms second region R 2 . In the thickness direction (Z axis direction) of laminated casing  110 , second portion P 2  is located backward with respect to first portion P 1 . Since second portion P 2  is located backward, it is expected to attain a small pressure difference between first region R 1  and second region R 2 . Thus, for example, it is expected to reduce a difference in welding strength between first region R 1  and second region R 2 . As with first horn  211 , second horn  212  may also include a first portion and a second portion. 
     For example, a slit  5  (through hole) may be formed in at least one of first horn  211  and second horn  212 . By forming slit  5 , it is expected to attain a uniform amplitude of the horn within the contact surface. 
     &lt;Battery Production Apparatus&gt; 
       FIG.  5    is a conceptual diagram showing a battery production apparatus according to the present embodiment. Hereinafter, the “battery production apparatus according to the present embodiment” can be simply referred to as “the present production apparatus”. The present production apparatus  200  includes first horn  211 , second horn  212 , pressure applying apparatus  220 , first ultrasonic wave generating apparatus  231 , and second ultrasonic wave generating apparatus  232 . In the present production apparatus  200 , the present production method described above can be performed. That is, the present production apparatus  200  can form sealed portion  115  at the peripheral edge of laminated casing  110  in which electrode assembly  120  is accommodated. 
     &lt;&lt;First and Second Horns&gt;&gt; 
     First horn  211  and second horn  212  are configured to sandwich at least a portion of the peripheral edge of laminated casing  110  between first horn  211  and second horn  212 . First horn  211  is attached to first ultrasonic wave generating apparatus  231 . Second horn  212  is attached to second ultrasonic wave generating apparatus  232 . First horn  211  and second horn  212  may be replaceable. Details of first horn  211  and second horn  212  are as described above. 
     &lt;&lt;Pressure Applying Apparatus&gt;&gt; 
     Pressure applying apparatus  220  applies pressure applying force to at least one of first horn  211  and second horn  212 . In  FIG.  5   , the pressure applying force is applied to first horn  211  as an example. The pressure applying force may be applied to second horn  212 . The pressure applying force may be applied to both first horn  211  and second horn  212 . Pressure applying apparatus  220  can apply the pressure applying force by any method. Pressure applying apparatus  220  may include, for example, an air cylinder, an actuator, a servo motor, and the like. 
     &lt;&lt;First and Second Ultrasonic Wave Generating Apparatus&gt;&gt; 
     First ultrasonic wave generating apparatus  231  is configured to apply, to first horn  211 , ultrasonic vibration in first vibration direction V 1 . Second ultrasonic wave generating apparatus  232  is configured to apply, to second horn  212 , ultrasonic vibration in second vibration direction V 2 . First vibration direction V 1  is parallel to the thickness direction of laminated casing  110 . Second vibration direction V 2  is non-parallel to first vibration direction V 1 . 
     Second ultrasonic wave generating apparatus  232  generates ultrasonic vibration independently of first ultrasonic wave generating apparatus  231 . For example, it is considered to apply ultrasonic vibration from one ultrasonic wave generating apparatus to both first horn  211  and second horn  212 . In this case, the two horns are vibrated, so that the ultrasonic wave generating apparatus is required to attain a high output. Further, the vibration direction of first horn  211  or second horn  212  may be converted by a vibration direction converter. By the conversion of the vibration direction, vibration energy may be lost. Therefore, the output is required to be further increased. When two ultrasonic wave generating apparatuses are used and one horn is assigned to one ultrasonic wave generating apparatus, the output is expected to be reduced. The frequency of each of first ultrasonic wave generating apparatus  231  and second ultrasonic wave generating apparatus  232  may be, for example, 20 kHz or less, or 5 to 20 kHz. 
     Each of first ultrasonic wave generating apparatus  231  and second ultrasonic wave generating apparatus  232  may independently include an oscillator, a vibrator, a booster, or the like, for example. The oscillator can generate high-frequency power. The vibrator can convert the high-frequency power into ultrasonic vibration. The booster can adjust the amplitude of the ultrasonic vibration. The booster can transmit the ultrasonic vibration to the horn. Second ultrasonic wave generating apparatus  232  may generate ultrasonic vibration in synchronism with first ultrasonic wave generating apparatus  231 , or may generate ultrasonic vibration not in synchronism with first ultrasonic wave generating apparatus  231 . 
     &lt;&lt;Other Apparatuses etc.&gt;&gt; 
     The present production apparatus  200  may further include, for example, a stage (not shown), a driving apparatus (not shown), a controller (not shown) and the like. The stage can support a workpiece. The driving apparatus may drive first horn  211  in parallel with the thickness direction of the workpiece, for example. The controller may control individual operation, cooperation, and the like of each apparatus. 
     &lt;Battery&gt; 
     The present battery  100  is a laminate-type battery. The present battery  100  can be produced by the present production method. The present battery  100  can have, for example, a flat outer shape. The present battery  100  includes laminated casing  110  and electrode assembly  120  (see  FIG.  2   ). The present battery  100  may further include, for example, electrode tab  130 , tab film  140 , and the like. 
     &lt;&lt;Electrode Assembly&gt;&gt; 
     Electrode assembly  120  is a power generation element. Electrode assembly  120  includes a positive electrode and a negative electrode. Electrode assembly  120  may include a bipolar electrode. Each of the electrodes may be in the form of a sheet. Electrode assembly  120  may further include, for example, a separator, an electrolyte, and the like. Electrode assembly  120  can have any form. Electrode assembly  120  may be, for example, of a wound type or stacked type. 
     &lt;&lt;Laminated Casing&gt;&gt; 
     Laminated casing  110  accommodates electrode assembly  120 . When viewed in a plan view ( FIG.  2   ), laminated casing  110  includes sealed portion  115  at the peripheral edge of laminated casing  110 . Sealed portion  115  surrounds electrode assembly  120 . Sealed portion  115  includes first region R 1  and second region R 2 . In first region R 1 , the portions of laminated casing  110  are welded to each other. In second region R 2 , electrode tab  130  is sandwiched between the portions of laminated casing  110 . 
       FIG.  6    is a conceptual diagram of the battery according to the present embodiment. In a cross section parallel to the XZ plane, laminated casing  110  (sealed portion  115 ) includes a first metal layer  111 , a first resin layer  113 , and a second metal layer  112 . Laminated casing  110  may further include second resin layers  114 . Laminated casing  110  may have a thickness of, for example, 50 to 500 μm as a whole. 
     First resin layer  113  is interposed between first metal layer  111  and second metal layer  112 . First resin layer  113  is formed by welding two resin layers. First resin layer  113  includes a first joining interface B 1 . First joining interface B 1  may have, for example, recesses/projections (undulations) with relatively short intervals. It is considered that the recesses/projections with short intervals result from the ultrasonic vibrations in the two directions. An interval of the recesses/projections may be, for example, 1 to 30 μm. An interval of the recesses/projections represents a distance between adjacent projections. 
     Second resin layers  114  cover the surfaces of laminated casing  110 . Each of first resin layer  113  and second resin layers  114  may independently include polypropylene (PP), polyethylene terephthalate (PET), or the like, for example. Second resin layer  114  may have a composition that is the same as or different from that of first resin layer  113 . First resin layer  113  may have a thickness of, for example, 10 to 200 μm. Second resin layer  114  may have a thickness of, for example, 5 to 50 μm. 
     Sealed portion  115  includes a first surface S 1  and a second surface S 2 . Second surface S 2  is a surface opposite to first surface S 1 . In  FIG.  6   , as an example, a processing mark M is formed on second surface S 2 . Processing mark M is formed on first surface S 1  or second surface S 2 . That is, when processing mark M is formed on second surface S 2 , no processing mark M is formed on first surface S 1 . When processing mark M is formed on first surface S 1 , no processing mark M is formed on second surface S 2 . 
     Processing mark M extends in a direction orthogonal to the thickness direction of laminated casing  110 . Processing mark M can be a streak-shaped scratch. Processing mark M may be referred to as processing scratch, welding mark, vibration mark, or the like. Processing mark M results from vibration in a direction intersecting the thickness direction of sealed portion  115 . That is, it is considered that second horn  212  forms processing mark M. On the other hand, it is considered that processing mark M is less likely to be formed by vibration in the direction parallel to the thickness direction. In other words, it is considered that first horn  211  is less likely to form processing mark M. 
     The extending direction of processing mark M can include a component parallel to second vibration direction V 2 . The extending direction of processing mark M may be parallel to second vibration direction V 2 . For example, the amplitude of second horn  212  can determine the size of processing mark M. The size of processing mark M may be, for example, 10 to 40 μm. The size of processing mark M represents the maximum width thereof in the Y axis direction in  FIG.  6   . 
       FIG.  7    is a conceptual diagram of a battery according to a reference embodiment. Hereinafter, the “battery according to the reference embodiment” may be simply referred to as “reference battery”. In reference battery  101 , second horn  212  is vibrated in parallel with first horn  211 , thereby forming a second joining interface B 2 . That is, both the two horns are vibrated in parallel with the thickness direction of laminated casing  110 . In reference battery  101 , second joining interface B 2  may have undulations with intervals longer than those in first joining interface B 1  ( FIG.  6   ). In reference battery  101 , none of first surface S 1  and second surface S 2  has processing mark M. Since second horn  212  is vibrated in the same direction as first horn  211 , excessive damage may be provided to first metal layer  111  and second metal layer  112 . 
     It should be noted that in the case of performing welding using a heat bar (in the case of heat sealing), it is considered that no undulations are formed at the joining interface. 
     &lt;&lt;Electrode Tab&gt;&gt; 
     Electrode tabs  130  is connected to electrode assembly  120  (a positive electrode or a negative electrode). Electrode tab  130  is led to the outside of laminated casing  110 . Electrode tab  130  extends through second region R 2  of sealed portion  115 . Electrode tab  130  may function as, for example, an external terminal. An external terminal, a bus bar, or the like may be connected to electrode tab  130 . Electrode tab  130  may include, for example, a metal plate or the like. Electrode tab  130  may include, for example, Al, nickel (Ni), copper (Cu), or the like. 
     In  FIG.  2   , two electrode tabs  130  (a positive electrode tab and a negative electrode tab) are led out from laminated casing  110  in opposite directions. For example, two electrode tabs  130  (the positive electrode tab and the negative electrode tab) may be led out from one side in the same direction. 
     &lt;&lt;Tab Film&gt;&gt; 
     Tab film  140  is interposed between electrode tab  130  and laminated casing  110 . Tab film  140  may strengthen airtightness around electrode tab  130 . Tab film  140  may include, for example, PP, PET, or the like. 
     The present embodiment is illustrative in any respect. The present embodiment is not restrictive. The technical scope of the present disclosure includes any modifications within the scope and meaning equivalent to the terms of the claims. For example, it is initially expected to extract freely configurations from the present embodiment and combine them freely.